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Hyperpolarization (physics)

Hyperpolarization is the nuclear spin polarization of a material in a magnetic field far beyond thermal equilibrium conditions determined by the Boltzmann distribution. It can be applied to gases such as 129Xe and 3He, and small molecules where the polarization levels can be enhanced by a factor of 104-105 above thermal equilibrium levels. Hyperpolarized noble gases are typically used in magnetic resonance imaging (MRI) of the lungs. Hyperpolarized small molecules are typically used for in vivo metabolic imaging. For example, a hyperpolarized metabolite can be injected into animals or patients and the metabolic conversion can be tracked in real-time. Other applications include determining the function of the neutron spin-structures by scattering polarized electrons from a very polarized target (3He), surface interaction studies, and neutron polarizing experiments.

Introduction
Spin exchange optical pumping (SEOP) is one of several hyperpolarization techniques discussed on this page. This technique specializes in creating hyperpolarized (HP) noble gases, such as 3He, 129Xe, and quadrupolar 131Xe, 83Kr, and 21Ne. Noble gases are required because SEOP is performed in the gas phase, they are chemically inert, non-reactive, chemically stable with respect to alkali metals, and their T1 is long enough to build up polarization. Spin 1/2 noble gases meet all these requirements, and spin 3/2 noble gases do to an extent, although some spin 3/2 do not have a sufficient T1. Each of these noble gases has their own specific application, such as characterizing lung space and tissue via in vivo molecular imaging and functional imaging of lungs, to study changes in metabolism of healthy versus cancer cells, or use as targets for nuclear physics experiments. During this process, circularly polarized infrared laser light, tuned to the appropriate wavelength, is used to excite electrons in an alkali metal, such as caesium or rubidium inside a sealed glass vessel. Infrared light is necessary because it contains the wavelengths necessary to excite the alkali metal electrons, although the wavelength necessary to excite sodium electrons is below this region (Table 1). The angular momentum is transferred from the alkali metal electrons to the noble gas nuclei through collisions. Nitrogen is used as a quenching gas, which prevents the fluorescence of the polarized alkali metal, which would lead to de-polarization of the noble gas. If fluorescence was not quenched, the light emitted during relaxation would be randomly polarized, working against the circularly polarized laser light. While different sizes of glass vessels (also called cells), and therefore different pressures, are used depending on the application, one amagat of total pressure of noble gas and nitrogen is sufficient for SEOP and 0.1 amagat of nitrogen density is needed to quench fluorescence. Great improvements in 129Xe hyperpolarization technology have achieved > 50% level at flow rates of 1–2 L/min, which enables human clinical applications.

History
The discovery of SEOP took decades for all the pieces to fall into place to create a complete technique. First, in 1897, Zeeman's studies of sodium vapor led to the first result of optical pumping. The next piece was found in 1950 when Kastler determined a method to electronically spin-polarize rubidium alkali metal vapor using an applied magnetic field and illuminating the vapor with resonant circularly polarized light. Ten years later, Marie-Anne Bouchiat, T. M. Carver, and C. M. Varnum performed spin exchange, in which the electronic spin polarization was transferred to nuclear spins of a noble gas (3He and 129Xe) through gas-phased collisions. Since then, this method has been greatly improved and expanded to use with other noble gases and alkali metals.

Theory
To explain the processes of excitation, optical pumping, and spin exchange easier, the most common alkali metal used for this process, rubidium, will be used as an example. Rubidium has an odd number of electrons, with only one in the outermost shell that can be excited under the right conditions. There are two transitions that can occur, one referred to as the D1 line where the transition occurs from the 52S1/2 state to the 52P1/2 state and another referred to the D2 line where the transition occurs from the 52S1/2 to the 52P3/2 state. The D1 and D2 transitions can occur if the rubidium atoms are illuminated with light at a wavelength of 794.7 nm and 780 nm, respectively (Figure 1). While it is possible to cause either excitation, laser technology is well-developed for causing the D1 transition to occur. Those lasers are said to be tuned to the D1 wavelength (794.7 nm) of rubidium. In order to increase the polarization level above thermal equilibrium, the populations of the spin states must be altered. In the absence of magnetic field, the two spin states of a spin I = $1⁄2$ nuclei are in the same energy level, but in the presence of a magnetic field, the energy levels split into ms = ±1/2 energy levels (Figure 2). Here, ms is the spin angular momentum with possible values of +1/2 (spin up) or -1/2 (spin down), often drawn as vectors pointing up or down, respectively. The difference in population between these two energy levels is what produces an NMR signal. For example, the two electrons in the spin down state cancel two of the electrons in the spin up state, leaving only one spin up nucleus to be detected with NMR. However, the populations of these states can be altered via hyperpolarization, allowing the spin up energy level to be more populated and therefore increase the NMR signal. This is done by first optically pumping alkali metal, then transferring the polarization to a noble gas nucleus to increase the population of the spin up state. The absorption of laser light by the alkali metal is the first process in SEOP. Left-circularly polarized light tuned to the D1 wavelength of the alkali metal excites the electrons from the spin down 2S1/2 (ms=-1/2) state into the spin up 2P1/2 (ms=+1/2) state, where collisional mixing then occurs as the noble gas atoms collide with the alkali metal atoms and the ms=-1/2 state is partially populated (Figure 3). Circularly polarized light is necessary at low magnetic fields because it allows only one type of angular momentum to be absorbed, allowing the spins to be polarized. Relaxation then occurs from the excited states (ms=±1/2) to the ground states (ms=±1/2) as the atoms collide with nitrogen, thus quenching any chance of fluorescence and causing the electrons to return to the two ground states in equal populations. Once the spins are depolarized (return to the ms=-1/2 state), they are excited again by the continuous wave laser light and the process repeats itself. In this way, a larger population of electron spins in the ms=+1/2 state accumulates. The polarization of the rubidium, PRb, can be calculated by using the formula below:

 * $${P_{Rb}}={{\mathrm{n}_\uparrow-\mathrm{n}_\downarrow}\over{\mathrm{n}_\uparrow+\mathrm{n}_\downarrow}}$$

Where n↑ and n↓ and  are the number of atoms in the spin up (mS=+1/2) and spin down (mS=-1/2) 2S1/2 states. Next, the optically pumped alkali metal collides with the noble gas, allowing for spin exchange to occur where the alkali metal electron polarization is transferred to the noble gas nuclei (Figure 4). There are two mechanisms in which this can occur. The angular momentum can be transferred via binary collisions (Figure 4A, also called two-body collisions) or while the noble gas, N2 buffer gas, and vapor phase alkali metal are held in close proximity via van der Waals forces (Figure 4B, also called three body collisions). In cases where van der Waals forces are very small compared to binary collisions (such is the case for 3He), the noble gas and alkali metal collide and polarization is transferred from the AM to the noble gas. Binary collisions are also possible for 129Xe. At high pressures, van der Waals forces dominate, but at low pressures binary collisions dominate.

Buildup of polarization
This cycle of excitation, polarization, depolarization, and re-polarization, etc. takes time before a net polarization is achieved. The buildup of nuclear polarization, PN(t), is given by:

 * $$\mathrm{P}_N(\mathrm{t})=\left \langle\mathrm{P}_A\right \rangle \left ( \frac{\gamma_{SE}}{\gamma_{SE}+\Gamma} \right ) [1-e^{(\gamma_{SE}+\Gamma)\mathrm{t}}]$$

Where ⟨PA⟩ is the alkali metal polarization, γSE is the spin exchange rate, and Γ is the longitudinal relaxation rate of the noble gas. Relaxation of the nuclear polarization can occur via several mechanisms and is written as a sum of these contributions:

 * $$\Gamma=\Gamma_t+\Gamma_p+\Gamma_g+\Gamma_w$$

Where Γt, Γp, Γg, and Γw represent the relaxation from the transient Xe2 dimer, the persistent Xe2 dimer, diffusion through gradients in the applied magnetic field, and wall relaxation, respectively. In most cases, the largest contributors to the total relaxation are persistent dimers and wall relaxations. A Xe2 dimer can occur when two Xe atoms collide and are held together via van der Waals forces, and it can be broken when a third atom collides with it. It is similar to Xe-Rb during spin exchange (spin transfer) where they are held in close proximity to each other via van der Waals forces. Wall relaxation is when the hyperpolarized Xe collides with the walls of the cell and is de-polarized due to paramagnetic impurities in the glass.

The buildup time constant, ΓB, can be measured by collecting NMR spectra at time intervals falling within the time it takes to reach steady-state polarization (i.e. the maximum polarization that can be achieved, seen by the maximum signal output). The signal integrals are then plotted over time and can be fit to obtain the buildup time constant. Collecting a buildup curve at several different temperatures and plotting the values as a function of alkali metal vapor density (since vapor density increases with an increase in cell temperature) can be used to determine the spin destruction rate and the per-atom spin exchange rate using:

 * $$\Gamma_B=\gamma'\times[AM]+\Gamma_{SD}$$

Where γ' is the per-atom spin exchange rate, [AM] is the alkali metal vapor density, and ΓSD is the spin destruction rate. This plot should be linear, where γ' is the slope and ΓSD is the y-intercept.

Relaxation: T1
Spin exchange optical pumping can continue indefinitely with continuous illumination, but there are several factors that cause relaxation of polarization and thus a return to the thermal equilibrium populations when illumination is stopped. In order to use hyperpolarized noble gases in applications such as lung imaging, the gas must be transferred from the experimental setup to a patient. As soon as the gas is no longer actively being optically pumped, the degree of hyperpolarization begins to decrease until thermal equilibrium is reached. However, the hyperpolarization must last long enough to transfer the gas to the patient and obtain an image. The longitudinal spin relaxation time, denoted as T1, can be measured easily by collecting NMR spectra as the polarization decreases over time once illumination is stopped. This relaxation rate is governed by several depolarization mechanisms and is written as:

 * $$\frac{1}{\mathrm{T}_1}=\left ( \frac{1}{T_1} \right )_{CR}+\left ( \frac{1}{T_1} \right )_{MFI}+\left ( \frac{1}{T_1} \right )_{O2}$$

Where the three contributing terms are for collisional relaxation (CR), magnetic field inhomogeneity (MFI) relaxation, and relaxation caused by the presence of paramagnetic oxygen (O2). The T1 duration could be anywhere from minutes to several hours, depending on how much care is put into lessening the effects of CR, MFI, and O2. The last term has been quantified to be 0.360 s−1 amagat−1, but the first and second terms are hard to quantify since the degree of their contribution to the overall T1 is dependent on how well the experimental setup and cell are optimized and prepared.

Experimental setup in SEOP
In order to perform SEOP, it is first necessary to prepare the optical cell. Optical cells (Figure 5) are designed for the particular system in mind and glass blown using a transparent material, typically pyrex glass (borosilicate). This cell must then be cleaned to eliminate all contaminants, particularly paramagnetic materials which decrease polarization and the T1. The inner surface of the cell is then coated to (a) serve as a protective layer for the glass in order to lessen the chance of corrosion by the alkali metal, and (b) minimize depolarization caused by the collisions of polarized gas molecules with the walls of the cell. Decreasing wall relaxation leads to longer and higher polarization of the noble gas. While several coatings have been tested over the years, SurfaSil (Figure 6, now referred to as hydrocarbon soluble siliconizing fluid) is the most common coating used in a ratio of 1:10 SurfaSil: hexane because it provides long T1 values. The thickness of the SurfaSil layer is about 0.3-0.4 μm. Once evenly coated and dried, the cell is then placed in an inert environment and a droplet of alkali metal (≈200 mg) is placed in the cell, which is then dispersed to create an even coating on the walls of the cells. One method for transferring the alkali metal into the cell is by distillation. In the distillation method, the cell is connected to a glass manifold equipped to hold both pressurized gas and vacuum, where an ampoule of alkali metal is connected. The manifold and cell are vacuumed, then the ampoule seal is broken and the alkali metal is moved into the cell using the flame of a gas torch. The cell is then filled with the desired gas mixture of nitrogen and noble gas. Care must be taken not to poison the cell at any stage of cell preparation (expose the cell to atmospheric air).

Several cell sizes and designs have been used over the years. The application desired is what governs the design of the optical pumping cell and is dependent on laser diameter, optimization needs, and clinical use considerations. The specific alkali metal(s) and gases are also chosen based on the desired applications. Once the cell is complete, a surface coil (or coils, depending on the desired coil type) is taped to the outside of the cell, which a) allows RF pulses to be produced in order to tip the polarized spins into the detection field (x,y plane) and b) detects the signal produced by the polarized nuclear spins. The cell is placed in an oven which allows for the cell and its contents to be heated so the alkali metal enters the vapor phase, and the cell is centered in a coil system which generates an applied magnetic field (along the z-axis). A laser, tuned to the D1 line (electric-dipole transition ) of the alkali metal and with a beam diameter matching the diameter of the optical cell, is then aligned with the optical flats of the cell in such a way where the entirety of the cell is illuminated by laser light to provide the largest polarization possible (Figure 7). The laser can be anywhere between tens of watts to hundreds of watts, where higher the power yields larger polarization but is more costly. In order to further increase polarization, a retro-reflective mirror is placed behind the cell in order to pass the laser light through the cell twice. Additionally, an IR iris is placed behind the mirror, providing information of laser light absorption by the alkali metal atoms. When the laser is illuminating the cell, but the cell is at room temperature, the IR iris is used to measure the percent transmittance of laser light through the cell. As the cell is heated, the rubidium enters the vapor phase and starts to absorb laser light, causing the percent transmittance to decrease. The difference in the IR spectrum between a room temperature spectrum and a spectrum taken while the cell is heated can be used to calculate an estimated rubidium polarization value, PRb.

As SEOP continues to develop and improve, there are several types of NMR coils, ovens, magnetic field generating coils, and lasers that have been and are being used to generate hyperpolarized gases. Generally, the NMR coils are hand made for the specific purpose, either by turning copper wire by hand in the desired shape, or by 3D printing the coil. Commonly, the oven is a forced-air oven, with two faces made of glass for the laser light to pass through the cell, a removable lid, and a hole through which a hot air line is connected, which allows the cell to be heated via conduction. The magnetic field generating coils can be a pair of Helmholtz coils, used to generate the desired magnetic field strength, whose desired field is governed by:

 * $$\omega=\gamma\mathrm{B}_0$$

Where ω is the Larmour frequency, or desired detection frequency, γ is the gyromagnetic ratio of the nuclei of interest, and B0 is the magnetic field required to detect the nuclei at the desired frequency. A set of four electromagnetic coils can also be used (i.e. from Acutran) and other coil designs are being tested.

In the past, laser technology was a limiting factor for SEOP, where only a couple alkali metals could be used due to the lack of, for example, cesium lasers. However, there have been several new developments, including better cesium lasers, higher power, narrower spectral width, etc. which are allowing the reaches of SEOP to increase. Nevertheless, there are several key features required. Ideally, the laser should be continuous wave to ensure the alkali metal and noble gas remains polarized at all times. In order to induce this polarization, the laser light must be circularly polarized in the direction which allows the electrons to become spin polarized. This is done by passing the laser light through a polarizing beam splitter to separate the s and  p components, then through a quarter wave plate, which converts the linearly polarized light into circularly polarized light.

Noble gases and alkali metals
SEOP has successfully been used and is fairly well developed for 3He, 129Xe, and 83Kr for biomedical applications. Additionally, several improvements are under way to get enhanced and interpretable imaging of cancer cells in biomedical science. Studies involving hyperpolarization of 131Xe are underway, piquing the interest of physicists. There are also improvements being made to allow not only rubidium to be utilized in the spin transfer, but also cesium. In principle, any alkali metal can be used for SEOP, but rubidium is usually preferred due to its high vapor pressure, allowing experiments to be carried out at relatively low temperatures (80 °C-130 °C), decreasing the chance of damaging the glass cell. Additionally, laser technology for the alkali metal of choice has to exist and be developed enough get substantial polarization. Previously, the lasers available to excite the D1 cesium transition were not well-developed, but they are now becoming more powerful and less expensive. Preliminary studies even show that cesium may provide better results than rubidium, even though rubidium has been the go-to alkali metal of choice for SEOP.

The hyperpolarization method called spin-exchange optical pumping (SEOP) is being used to hyperpolarize noble gases such as Xenon-129 and Helium-3. When an inhaled hyperpolarized gas like 3He or 129Xe is imaged, there is a higher magnetization density of NMR-active molecules in the lung compared to traditional 1H imaging, which improves the MRI images that can be obtained. Unlike proton MRI which reports on anatomical features of lung tissues, XenonMRI reports lung function including gas ventilation, diffusion, and perfusion.

Rationale
Our target is to identify the infection or disease (cancer, for example) anywhere in our body like cerebral, brain, blood, and fluid, and tissues. This infectious cell is called collectively biomarker. According to the World Health Organization (WHO) and collaborating with United Nations and International Labor organization have convincingly defined the Biomarker as "any substance, structure, or process that can be measured in the body or its products and influence or predict the incidence of outcome or disease". Biomarker has to be quantifiable up-to certain level in biological process in well-being.

One specific example of biomarker is blood cholesterol that is commonly acquainted with us reliable for coronary heart disease; another biomarker is PSA (Prostate-Specific Antigen) and has been contributing to prostate cancer. There are a lot of biomarkers are considering as being cancer: Hepatitis C virus ribonucleic acid (HCV-RNA), International Normalized Ratio (INR), Prothrombin Time (PT), Monoclonal Protein (M protein), Cancer Antigen-125 (CA-125), Human Immunodeficiency Virus -Ribonucleic Acid (HIV RNA), B-type Natriuretic Peptide (BNP).27and Lymphoma cell (Ramos cell lines and Jurkat cell lines) a form of cancer.

Other common biomarkers are breast cancer, Ovarian cancer, Colorectal cancer, Lung cancer and brain tumor.

This disease-causing verdict agent is the biomarker is existing extremely trace amount especially initial state of the disease. Therefore, identifying or getting images of biomarker is tricky and, in few circumstances, uncertain by NMR tech. Hence, we must use the contrasting agent to enhance the images at least to visualize level to Physicians. As molecules of biomarker is less abundant in vivo system. The NMR or MRI experiment provides a very small signal even in some cases, the analyzer can miss the signal peak in data due to the lack in abundance of biomarkers. Therefore, to make sure, to reach the true conclusion about the existence of trouble-causing biomarkers, we need to enhance the probe (contrasting mechanisms) to get the clear peak at the most visible level of peak height as well as the position of the peak in data. If it is possible to gather the acceptable and clearly interpretable data from NMR or MRI experiment by using the contrasting agent, then experts can take a right initial step to recover the patients who already have been suffering from cancer. Among the various technique to get the enhanced data in MRI experiment, SEOP is one of them.

Researchers in SEOP are interested to use the 129Xe. Because 129Xe has a number of favorable facts in NMR Tech. for working as a contrasting agent even over the other novel gases:

 * Inert xenon does not show chemical reaction like other metals and non-metals because Xenon's electronic configuration is fully occupied as well as it is not radioactive also.
 * To get the solid, liquid state from naturally occurring gaseous state is easy going (figure-8). The solid and liquid state of 129Xe are existing experimentally doable temperature and pressure ranges.Xenontriple_state.jpg
 * Xenon possesses highly polarizable electron cloud surrounding the nucleus. Therefore, easily prone to be soluble with lipid or organic compounds especially in vivo environment in biological respect. (table-2)
 * Xenon does not alter the structurally or chemically (similarly other noble gases) when interacting with other molecules.
 * According to the scientist Ostwald, solubility is defined as the partition coefficient of the gas absorbed to the volume of the absorbing liquid. The solubility of Xenon, SXe(g) = V absorbed amount of Xe(g) /V absorbing liquid at standard temperature and pressure (STP).

Solubility of Xenon in water medium 11% means at 25 °C 11 mL Xenon gas could be absorbed by 100 mL of water.

 * Xenon atomic size is large and outer shell electrons are far from the nuclei, outermost electron is highly prone to be polarized specially lipid environment. Table 2 shows Xenon solubility in water medium at 37 °C is 8% but fat tissue in vivo environment the solubility value is 130%. Solubility leads the Xenon using in biological system as a contrasting agent.
 * Solvent effect of xenon is very large for of 129Xenon by the fact of solubility (table 2). Chemical shift value range for Xenon is more than 7500 ppm. However solvent effect is limited range for 1H & 13C (MRI active nuclei)  because of low chemical shift value range for 1H is 20 ppm and for 13C is 300 ppm.  Therefore, using the 129Xe is preferred.

Figure-9 below, In NMR experimental data, there are different chemical shift values for different tissues in in vivo environment. All peaks are positioned through such a big range of chemical shift values for 129Xe is viable. Because 129Xe has long range up-to 1700ppm chemical shift value range in NMR data. Other important spectral information includes:

Figure 9. NMR data for Xe-129 biosensor in in vivo biological system.

 * Naturally 129Xe NMR peak has been counted as reference at 0.0ppm.
 * When 129Xe incorporated and bind with the Cryptophane-A molecule, then the chemical shift value in NMR acquisition shifted to around 70ppm.
 * If hyperpolarized 129Xe gas is dissolved into the brain, then five NMR spectral peaks can be observed.
 * Among them top sharp peak at 194.7ppm. In addition, at 189 ppm peak come out from the non-brain tissues.
 * Another two peaks are still unknown at 191.6 ppm and 197.8 ppm. At 209.5 ppm smaller but broad peak has been found in NMR data when 129Xe was dissolved in the blood stream.
 * Hyperpolarized 129Xe is very sensitive detector of biomarker (form of cancer in living system).
 * The nuclear spin polarization of 129Xe or in generally for noble gases we can increase up to fivefold via SEOP technique.
 * Using SEOP hyperpolarization technique, we can get images of uptake of xenon in the human brain tissue.

[[File:Figure-10.png|thumb|Figure 10. Measurements of the Polarization of 129Xe(g) in presence of low and intermediate magnetic fields. All (A-D) figures are NMR signal amplitude in μV/KHz vs Larmor Frequency in KHz. (A) Enhanced 129Xe(g) NMR signal at 62 kHz Larmor Frequency from the SEOP cell;

Xenon(g) has 1545 torr and Nitrogen(g) has 455 torr pressure and NMR data was collected in presence of 5.26mT magnetic field. (B) Reference NMR signal for water Proton Spin (111M), doping with CuSO4. 5H2O(s), 5.0mM and polarization has been created thermally in presence of 1.46 mT magnetic fields (number of scans was 170,000 times). (C) NMR data for Hyperpolarized 129Xe was collected in presence of 47.5mT magnetic fields.(129Xe was 300 torr and N2 was 1700 torr).(D) Reference NMR signal for 13C was collected from 170.0mM CH3COONa(l) in presence of 47.5mT magnetic field.32]] (Figure-10) 129Xe(g) shows satisfactory enhancement in polarization during SEOP compared to the thermal enhancement in polarization. This is demonstrated by the experimental data values when NMR spectra are acquired at different magnetic field strengths. A couple of important points from experimental data are:

 * The 129Xe polarization has increased about 144,000-fold in SEOP tech. over thermally enhanced for 1H polarization in NMR experiment. Both experiments that showed this have been done in identical conditions and using same radio frequency during NMR experiment.
 * A similar value of 140,000-fold signal enhancement for 129Xe hyperpolarization in SEOP compare to the reference thermally enhanced 13C NMR signal is also seen in experimental NMR data. Both data have been collected in identical Larmor frequency and other experimental conditions and same radio frequency during NMR data collection.

(Figure 11) Longitudinal spin relaxation time (T1) is very sensitive with an increase of magnetic field and hence enhance the NMR signals is noticeable in SEOP in case of 129Xe. As T1 is higher for blue marking conditioning NMR experiment shows more enhanced peak compare to other. For hyperpolarized 129Xe in tedlar bags, the T1 is 38±12 minutes when data collected in presence of 1.5 mT magnetic field. However, satisfactory increment in T1delay time (354±24 minutes) when data was collected in presence of 3000 mT magnetic field.

Use of Rb vs. Cs in SEOP NMR experiments
In general, we can use the either 87Rb or 133Cs alkali metal atoms with inert nitrogen gas. However, we are using 133Cs atoms with nitrogen to make the spin exchange with 129Xe for number of advantages:

 * 133Cs has natural perfect abundance while rubidium has two (85Rb and 87Rb) isotopes. Abstraction of one isotope separately from these two (85Rb and 87Rb) is difficult compare to collect the 133Cs isotope. Abstraction of 133Cs is convenient.
 * Optical pumping cell normally is operated at lower temperature to avoid chemically breakdown issue. SEOP is using 133Cs at low temperature and hence it has fewer chemical corrosion with SEOP cell wall glass.
 * 133Cs-129Xe couple have spin exchange rate about 10% that is more compare to the 87Rb-129Xe couple have.

Although 129Xe has a bunch of preferable characteristic applications in NMR technique, 83Kr can also be used since it has a lot of advantages in NMR techniques in different ways than 129Xe.

 * 83Kr stable isotope has spin I=9/2 and has larger Van der Waals size 2.02A0. It has quadrupolar effect can be diffuse to nearby environment shortly & distinctively (polar to nonpolar media in vivo system).
 * Chemical composition of materials can influence the longitudinal relaxation of hyperpolarized 83Kr.
 * The relaxation can distinguish among the hydrophobic and hydrophilic substrate. Although 3He and 129Xe have spin half but they are not quadrupolar active.
 * However, the 21Ne (I=3/2), 83Kr(I=9/2) and 131Xe (I=3/2) have Quadrupolar moment.34 Quadrupolar interactions make these isotopes having spin relaxation.
 * Due to this spin relaxation and evolution, these isotopes can be used as contrasting agents to say about the probe can determine the structural feature and chemical compositions of the surfaces for a permeable media.
 * SEOP can calculate the relaxation of spin T1 by using the equation nonlinear least-squares fitting for 83Kr signal as a function of time as well as experimental number of media flip angle (≈12°) for NMR experimenting radio frequency pulses.
 * Hyperpolarized 83Kr is being separated from 87Rb gases after spin exchanging in the optical pumping process and then used in variety of in vivo system to get MRI signal. This is the first isotope showed lots of applicability for MRI technique even though has the spin is $9 1⁄2$.
 * During experiment of canine lung tissue, the using magnet was 9.4 T, media was porous and similar porosity to alveolar dimensions which is disseminated at atmospheric pressure. Spin lattice relaxation was reasonably long enough so it is applicable in vivo system although the oxygen level could be 20%.
 * As 83Kr contrasting agent is promising to develop pristine in vivo MRI methodology to identify the lung diseases epically those effect have been caused in parenchyma surface due to the surfactant concentration.
 * Boyed the boundary this particular contrasting agent can work to figure out the size of pour of porous media in materials science.
 * In addition, this technique can take us about to prepare the surface coating, spatial fluctuations of surfaces. Eventually, never ending the good sign of this contrasting agent like natural abundance (11.5% of 83Kr) makes it easy to get with reasonable price $5/L.

Imaging applications of SEOP
Steps are also being taken in academia and industry to use this hyperpolarized gas for lung imaging. Once the gas (129Xe) is hyperpolarized through the SEOP process and the alkali metal is removed, a patient (either healthy or suffering from a lung disease), can breathe in the gas and an MRI can be taken. This results in an image of the spaces in the lungs filled with the gas. While the process to get to the point of imaging the patient may require knowledge from scientists very familiar with this technique and the equipment, steps are being taken to eliminate the need for this knowledge so that a hospital technician would be able to produce the hyperpolarized gas using a polarizer.

Hyperpolarization machines are currently being used to develop hyperpolarized xenon gas that is used as a visualization agent for the lungs. Xenon-129 is a safe inert noble gas that can be used to quantify lung function. With a single 10-second breath hold, hyperpolarized Xenon-129 is used with MRI to enable 3-dimensional lung imaging. Xenon MRI is being used to monitor patients with pulmonary-vascular, obstructive, or fibrotic lung disease.

Temperature-ramped 129Xe SEOP in an automated high-output batch model hyperpolarized 129Xe can utilize three prime temperature range to put certain conditions: First, 129Xe hyperpolarization rate is superlative high at hot condition. Second, in warm condition the hyperpolarization of 129Xe is unity. Third, at cold condition, the level of hyperpolarization of 129Xe gas at least can get the (at human body's temperature) imaging although during the transferring into the Tedlar bag having poor percentage of 87Rb (less than 5 ng/L dose).

Multiparameter analysis of 87Rb/129Xe SEOP at high xenon pressure and photon flux could be used as 3D-printing and stopped flow contrasting agent in clinical scale. In situ technique, the NMR machine was run for tracking the dynamics of 129Xe polarization as a function of SEOP-cell conditioning with different operating parameters such as data collecting temperature, photon flux, and 129Xe partial pressure to enhance the 129Xe polarization (PXe). All of those polarization values of 129Xe has been approved by pushing the hyperpolarized 129Xe gas and all MRI experiment also done at lower magnetic field 47.5 mT. Finally demonstrations indicated that such a high pressure region, polarization of 129Xe gases could be increment even more that the limit that already has been shown. Better SEOP thermal management and optimizing the polarizing kinetics has been further improved with good efficacy.

SEOP on solids
Not only can SEOP be used to hyperpolarize noble gases, but a more recent development is SEOP on solids. It was first performed in 2007 and was used to polarize nuclei in a solid, allowing for nuclei that cannot be polarized by other methods to become hyperpolarized. For example, nuclear polarization of 133Cs in the form of a solid film of CsH can be increased above the Boltzmann limit. This is done by first optically pumping cesium vapor, then transferring the spin polarization to CsH salt, yielding an enhancement of 4.0.

The cells are made as previously described using distillation, then filled with hydrogen gas and heated to allow for the Cs metal to react with the gaseous hydrogen to form the CsH salt. Unreacted hydrogen was removed, and the process was repeated several times to increase the thickness of the CsH film, then pressurized with nitrogen gas. Usually, SEOP experiments are done with the cell centered in Helmholtz or electromagnetic coils, as previously described, but these experiments were done in a superconducting 9.4 T magnet by shining the laser through the magnet and electrically heating the cell. In the future, it may be possible to use this technique to transfer polarization to 6Li or 7Li, leading to even more applications since the T1 is expected to be longer. Since the discovery of this technique that allows solids to be characterized, it has been improved in such a way where polarized light is not necessary to polarize the solid; instead, unpolarized light in a magnetic field can be used. In this method, glass wool is coated with CsH salt, increasing the surface area of the CsH and therefore increasing the chances of spin transfer, yielding 80-fold enhancements at low field (0.56 T). Like in hyperpolarizing CsH film, the cesium metal in this glass wool method was allowed to react with hydrogen gas, but in this case the CsH formed on the glass fibers instead of the glass cell.

Metastability exchange optical pumping
3He can also be hyperpolarized using metastability exchange optical pumping (MEOP). This process is able to polarize 3He nuclei in the ground state with optically pumped 3He nuclei in the metastable state. MEOP only involves 3He nuclei at room temperature and at low pressure (≈a few mbars). The process of MEOP is very efficient (high polarization rate), however, compression of the gas up to atmospheric pressure is needed.

Dynamic nuclear polarization
Compounds containing NMR-sensitive nuclei, such as 1H, 13C or 15N, can be hyperpolarized using Dynamic nuclear polarization (DNP). DNP is typically performed at low temperature (≈1 K) and high magnetic field (≈3 T). The compound is subsequently thawed and dissolved to yield a room temperature solution containing hyperpolarized nuclei. This liquid can be used in in vivo metabolic imaging for oncology and other applications. The 13C polarization levels in solid compounds can reach up to ≈64% and the losses during dissolution and transfer of the sample for NMR measurements can be minimized to a few percent. Compounds containing NMR-active nuclei can also be hyperpolarized using chemical reactions with para-hydrogen, see Para-Hydrogen Induced Polarization (PHIP).

Parahydrogen induced polarization
Molecular hydrogen, H2, contains two different spin isomers, para-hydrogen and ortho-hydrogen, with a ratio of 25:75 at room temperature. Creating para-hydrogen induced polarization (PHIP) means that this ratio is increased, in other words that para-hydrogen is enriched. This can be accomplished by cooling hydrogen gas and then inducing ortho-to-para conversion via an iron-oxide or charcoal catalyst. When performing this procedure at ≈70 K (i.e. with liquid nitrogen), para-hydrogen is enriched from 25% to ca. 50%. When cooling to below 20 K and then inducing the ortho-to-para conversion, close to 100% parahydrogen can be obtained.

For practical applications, the PHIP is most commonly transferred to organic molecules by reacting the hyperpolarized hydrogen with precursor molecules in the presence of a transition metal catalyst. Proton NMR signals with ca. 10,000-fold increased intensity can be obtained compared to NMR signals of the same organic molecule without PHIP and thus only "thermal" polarization at room temperature.

Signal amplification by reversible exchange (SABRE)
Signal amplification by reversible exchange (SABRE) is a technique to hyperpolarize samples without chemically modifying them. Compared to orthohydrogen or organic molecules, a much greater fraction of the hydrogen nuclei in parahydrogen align with an applied magnetic field. In SABRE, a metal center reversibly binds to both the test molecule and a parahydrogen molecule facilitating the target molecule to pick up the polarization of the parahydrogen. This technique can be improved and utilized for a wide range of organic molecules by using an intermediate "relay" molecule like ammonia. The ammonia efficiently binds to the metal center and picks up the polarization from the parahydrogen. The ammonia then transfers it other molecules that don't bind as well to the metal catalyst. This enhanced NMR signal allows the rapid analysis of very small amounts of material.

title: Hyperpolarization (physics)


text:
Samuel Maverick Jr.

Samuel Augustus Maverick Jr. (1837–1936) was a Texas soldier and businessman, born May 14, 1837, at Montpelier Plantation, near Pendleton, South Carolina, the first-born of Samuel Augustus Maverick and Mary Ann Adams. His parents brought him to Texas in June 1838 and he grew up in San Antonio during the Republic. In two volumes of memoirs, he recounted his memories of the Council House Fight in 1840 (in which the family's cook saved his life), the evacuation of the city during the incursion by Gen. Rafael Vásquez in 1842, and his father's return from the prison at Perote, Veracruz, in 1843.

Maverick's early education was provided by tutors, and he later attended several local private schools. In 1856, he traveled to Scotland to attend the University of Edinburgh, from which he graduated, probably in 1859.

At the outbreak of the Civil War in 1861, Maverick enlisted in Company B of the First Texas Mounted Rifles under Col. Henry E. McCulloch, but the unit saw insufficient action to satisfy him. In May 1862, he joined Company G of the 8th Texas Infantry, commanded by Col. Benjamin F. Terry and known as Terry's Texas Rangers, with whom he saw action throughout the South. At Fort Donelson, Tennessee, he swam the Cumberland River and set fire to a Union gunboat, for which feat he was commissioned a Second Lieutenant.

After the war, Maverick returned to San Antonio, where he farmed on the land that now makes up Brackenridge Park, north of downtown. In 1867, he passed the state bar examination. He subsequently ran a series of businesses, including a lumberyard and several stores. In 1884 he built the Maverick Bank at the corner of East Houston Street and Alamo Plaza, but the bank failed in 1892. He retired from active business in 1906.

He was long involved in preservation efforts at the Alamo, and in 1888, he contributed $10,000 toward the construction of the Alamo Monument. In 1889, he escorted the Belknap Rifles, a local volunteer military company, to New York to participate in the centennial of the founding of Manhattan. He also donated land to San Antonio which was named Maverick Park in his honor.

Samuel Maverick married Sallie Frost on May 14, 1871 in San Antonio and they had several children. He died in Austin February 27, 1936, at the age of ninety-eight, the last survivor of Terry's Texas Rangers, and was buried at Mission Burial Park in San Antonio.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Samuel Maverick Jr.


text:
Guillotine (game)

Guillotine is a card game created by Wizards of the Coast and designed by Paul Peterson. The game is set during the French Revolution, and was released on Bastille Day in 1998. The goal is to collect the heads of Nobles, accumulating points. Despite the grim topic of the game, the artwork is comical and the tone light.

Overview
Game play, for two to five players, takes approximately 30 minutes. Game equipment consists of two decks of cards, "Nobles" and "Actions", and a small cardboard structure representing the guillotine itself. This is mostly symbolic, though it can serve as a convenient indicator of the direction of the "line" of face-up Noble cards played on the game table representing condemned persons waiting to be beheaded. The Nobles cards carry points values and are collected by players after execution, while Action cards allow the player to perform various acts including rearranging the order of Nobles approaching the guillotine, stealing Nobles or Action cards from other players, enhancing the point values of certain categories of Nobles (see "Noble Types" below) and so forth.

Gameplay
The game is divided into three rounds or "days". Each day, twelve noble cards are dealt face-up in a row to be executed. A player's turn consists of:

 * 1) Playing an Action card. This is optional.
 * 2) Collecting the Noble card at the front of the line.
 * 3) Drawing an Action card from the deck.

Noble types
The Nobles come in five categories, each with its own color border:
 * Church (blue)
 * Military (red)
 * Royal (purple)
 * Negative (grey)
 * Civic (green)

Grey nobles, typically martyrs that have public sympathy, are worth negative points so the player's goal is to avoid collecting them if possible. Palace guards, in the red category, have a special value in that each guard is worth the total number of guards collected. Thus one guard is worth one point, two guards are worth four points, three guards are worth nine points and so forth. The other Nobles have values ranging from 1 to 5 points.

A typical turn example is a player using an Action card to move a Noble two places forward in the line, i.e. advance a high-point Noble from third position to first, collecting that Noble, then drawing another Action card to end the turn. Other Action cards allow the player to move a Noble one or more places backward, useful for moving a low- or negative-value card off the front of the line to collect a higher-value second-position Noble.

Certain Noble cards affect the game, including a "Fast Noble" requiring the player who collects it to also take the next Noble in line. A card symbolizing Maximilien Robespierre (beheaded in 1794) causes the "day" to instantly end upon his decapitation. At the end of a "day" of gameplay (either by the collection of the Robespierre card or the exhaustion of the line), a new line of Nobles is dealt face-up and play resumes. After three "days", the player with the highest point total wins.

Strategy
The key to winning the game is to manage which Nobles one collects through careful use of action cards while forcing other players to collect low- or negative-scoring Nobles. Some Action cards allow a player to prolong the "day" (by adding new Nobles to the line), shorten it by allowing Nobles to "escape," or end it, by playing the "Scarlet Pimpernel" action card.

Availability
After several years of Guillotine being out of print, Wizards re-released the game in 2005 alongside The Great Dalmuti, another Wizards card game.

In addition to being reprinted, Guillotine was featured as one of the playable games in Gleemax Games Alpha on the Gleemax website.

Reception
The reviewer from the online second volume of Pyramid stated that "Take France in the late 1700s. Add a large helping of various and sundry mostly useless nobility. Stir in a group of disaffected common citizens with no real political power. Then toss in a pinch of Professor Guillotine and agitate vigorously. Garnish with extremely amusing art and you have Guillotine, the hilarious new card game from Wizards of the Coast about trying to get a head." A review from Lautapeliopas praised the entertainment value, ease of play, and theme while criticising the components and omissions in the game's rules.

Guillotine won the 1998 Origins Award for Best Traditional Card Game.

Reviews

 * Family Games: The 100 Best
 * Backstab #51

title: Guillotine (game)


text:
Thromboxane

Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring.

Thromboxane is named for its role in blood clot formation (thrombosis).

Production
Thromboxane-A synthase, an enzyme found in platelets, converts the arachidonic acid derivative prostaglandin H2 to thromboxane.

People with asthma tend to have increased thromboxane production, and analogs of thromboxane act as bronchoconstrictors in patients with asthma.

Mechanism
Thromboxane acts by binding to any of the thromboxane receptors, G-protein-coupled receptors coupled to the G protein Gq.

Functions
Thromboxane is a vasoconstrictor and a potent hypertensive agent, and it facilitates platelet aggregation.

It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. The mechanism of secretion of thromboxanes from platelets is still unclear. They act in the formation of blood clots and reduce blood flow to the site of a clot.

If the cap of a vulnerable plaque erodes or ruptures, as in myocardial infarction, platelets stick to the damaged lining of the vessel and to each other within seconds and form a plug. These "Sticky platelets" secrete several chemicals, including thromboxane A2 that stimulate vasoconstriction, reducing blood flow at the site.

Role of A2 in platelet aggregation
Thromboxane A2 (TXA2), produced by activated platelets, has prothrombotic properties, stimulating activation of new platelets as well as increasing platelet aggregation.

Platelet aggregation is achieved by mediating expression of the glycoprotein complex GP IIb/IIIa in the cell membrane of platelets. Circulating fibrinogen binds these receptors on adjacent platelets, further strengthening the clot.

Pathology
It is believed that the vasoconstriction caused by thromboxanes plays a role in Prinzmetal's angina. Omega-3 fatty acids are metabolized to produce higher levels of TxA3, which is relatively less potent than TxA2 and PGI3; therefore, there is a balance shift toward inhibition of vasoconstriction and platelet aggregation. It is believed that this shift in balance lowers the incidence of myocardial infarction (heart attack) and stroke. Vasoconstriction and, perhaps, various proinflammatory effects exerted by TxA on tissue microvasculature, is probable reason why the TxA is pathogenic in various diseases, such as ischemia-reperfusion injury., hepatic inflammatory processes, acute hepatotoxicity etc. TxB2, a stable degradation product of TxA2, plays a role in acute hepatoxicity induced by acetaminophen.

Thromboxane inhibitors
Thromboxane inhibitors are broadly classified as either those that inhibit the synthesis of thromboxane, or those that inhibit the target effect of it.

Thromboxane synthesis inhibitors, in turn, can be classified regarding which step in the synthesis they inhibit:
 * The widely used drug aspirin acts by inhibiting the ability of the COX enzyme to synthesize the precursors of thromboxane within platelets. Low-dose, long-term aspirin use irreversibly blocks the formation of thromboxane A2 in platelets, producing an inhibitory effect on platelet aggregation. This anticoagulant property makes aspirin useful for reducing the incidence of heart attacks. 40 mg of aspirin a day is able to inhibit a large proportion of maximum thromboxane A2 release provoked acutely, with the prostaglandin I2 synthesis being little affected; however, higher doses of aspirin are required to attain further inhibition.
 * Thromboxane synthase inhibitors inhibit the final enzyme (thromboxane synthase) in the synthesis of thromboxane. Ifetroban is a potent and selective thromboxane receptor antagonist. Dipyridamole antagonizes this receptor too, but has various other mechanisms of antiplatelet activity as well.
 * High-dose naproxen can induce near-complete suppression of platelet thromboxane throughout the dosing interval and appears not to increase cardiovascular disease (CVD) risk, whereas other high-dose NSAID (non-steroidal-anti-inflammatory) regimens have only transient effects on platelet COX-1 and have been found to be associated "with a small but definite vascular hazard".

The inhibitors of the target effects of thromboxane are the thromboxane receptor antagonist, including terutroban.

Picotamide has activity both as a thromboxane synthase inhibitor and as a thromboxane receptor antagonist.

Ridogrel is another example.

title: Thromboxane


text:
Plasma oscillation

Plasma oscillations, also known as Langmuir waves (after Irving Langmuir), are rapid oscillations of the electron density in conducting media such as plasmas or metals in the ultraviolet region. The oscillations can be described as an instability in the dielectric function of a free electron gas. The frequency depends only weakly on the wavelength of the oscillation. The quasiparticle resulting from the quantization of these oscillations is the plasmon.

Langmuir waves were discovered by American physicists Irving Langmuir and Lewi Tonks in the 1920s. They are parallel in form to Jeans instability waves, which are caused by gravitational instabilities in a static medium.

Mechanism
Consider an electrically neutral plasma in equilibrium, consisting of a gas of positively charged ions and negatively charged electrons. If one displaces by a tiny amount an electron or a group of electrons with respect to the ions, the Coulomb force pulls the electrons back, acting as a restoring force.

'Cold' electrons
If the thermal motion of the electrons is ignored, it is possible to show that the charge density oscillates at the plasma frequency
 * $$\omega_{\mathrm{pe}} = \sqrt{\frac{n_\mathrm{e} e^{2}}{m^*\varepsilon_0}}, \left[\mathrm{rad/s}\right]$$ (SI units),
 * $$\omega_{\mathrm{pe}} = \sqrt{\frac{4 \pi n_\mathrm{e} e^{2}}{m^*}}, \left[\mathrm{rad/s}\right]$$ (cgs units),

where $$n_\mathrm{e}$$ is the number density of electrons, $$e$$ is the electric charge, $$m^*$$  is the effective mass of the electron, and $$\varepsilon_0$$ is the permittivity of free space. Note that the above formula is derived under the approximation that the ion mass is infinite. This is generally a good approximation, as the electrons are so much lighter than ions.

Proof using Maxwell equations. Assuming charge density oscillations $$\rho(\omega)=\rho_0 e^{-i\omega t}$$ the continuity equation: $$\nabla \cdot \mathbf{j} = - \frac{\partial \rho}{\partial t} = i \omega \rho(\omega) $$ the Gauss law $$\nabla \cdot \mathbf{E}(\omega) = 4 \pi \rho(\omega)$$ and the conductivity $$\mathbf{j}(\omega) = \sigma(\omega) \mathbf{E}(\omega)$$ taking the divergence on both sides and substituting the above relations: $$i \omega \rho(\omega) = 4 \pi \sigma(\omega) \rho(\omega)$$ which is always true only if $$1+ \frac {4 \pi i \sigma(\omega)}{\omega} = 0$$ But this is also the dielectric constant (see Drude Model) $$\epsilon(\omega) = 1+ \frac {4 \pi i \sigma(\omega)}{\omega} $$ and the condition of transparency (i.e. $$\epsilon \ge 0$$ from a certain plasma frequency $$\omega_{\rm p}$$ and above), the same condition here $$\epsilon = 0$$ apply to make possible also the propagation of density waves in the charge density.

This expression must be modified in the case of electron-positron plasmas, often encountered in astrophysics. Since the frequency is independent of the wavelength, these oscillations have an infinite phase velocity and zero group velocity.

Note that, when $$m^*=m_\mathrm{e}$$, the plasma frequency, $$\omega_{\mathrm{pe}}$$, depends only on physical constants and electron density $$n_\mathrm{e}$$. The numeric expression for angular plasma frequency is $$f_\text{pe} = \frac{\omega_\text{pe}}{2\pi}~\left[\text{Hz}\right]$$

Metals are only transparent to light with a frequency higher than the metal's plasma frequency. For typical metals such as aluminium or silver, $$n_\mathrm{e}$$ is approximately 1023 cm−3, which brings the plasma frequency into the ultraviolet region. This is why most metals reflect visible light and appear shiny.

'Warm' electrons
When the effects of the electron thermal speed $v_{\mathrm{e,th}} = \sqrt{k_\mathrm{B} T_{\mathrm{e}} / m_\mathrm{e}}$ are taken into account, the electron pressure acts as a restoring force as well as the electric field and the oscillations propagate with frequency and wavenumber related by the longitudinal Langmuir wave: $$ \omega^2 =\omega_{\mathrm{pe}}^2 +\frac{3k_\mathrm{B}T_{\mathrm{e}}}{m_\mathrm{e}}k^2=\omega_{\mathrm{pe}}^2 + 3 k^2 v_{\mathrm{e,th}}^2, $$ called the Bohm–Gross dispersion relation. If the spatial scale is large compared to the Debye length, the oscillations are only weakly modified by the pressure term, but at small scales the pressure term dominates and the waves become dispersionless with a speed of $$\sqrt{3} \cdot v_{\mathrm{e,th}}$$. For such waves, however, the electron thermal speed is comparable to the phase velocity, i.e., $$ v \sim v_{\mathrm{ph}} \ \stackrel{\mathrm{def}}{=}\ \frac{\omega}{k}, $$ so the plasma waves can accelerate electrons that are moving with speed nearly equal to the phase velocity of the wave. This process often leads to a form of collisionless damping, called Landau damping. Consequently, the large-k portion in the dispersion relation is difficult to observe and seldom of consequence.

In a bounded plasma, fringing electric fields can result in propagation of plasma oscillations, even when the electrons are cold.

In a metal or semiconductor, the effect of the ions' periodic potential must be taken into account. This is usually done by using the electrons' effective mass in place of m.

Plasma oscillations and the effect of the negative mass
Plasma oscillations may give rise to the effect of the “negative mass”. The mechanical model giving rise to the negative effective mass effect is depicted in Figure 1. A core with mass $$m_2$$ is connected internally through the spring with constant $$k_2$$ to a shell with mass $$m_1$$. The system is subjected to the external sinusoidal force $$F(t)=\widehat{F}\sin\omega t$$. If we solve the equations of motion for the masses $$m_1$$ and $$m_2$$ and replace the entire system with a single effective mass $$m_{\rm eff}$$ we obtain: $$m_{\rm eff}=m_1+{m_2\omega_0^2\over \omega_0^2-\omega^2},$$ where $\omega_0=\sqrt{k_2 / m_2}$. When the frequency $$\omega$$ approaches $$\omega_0$$ from above the effective mass $$m_{\rm eff}$$ will be negative. The negative effective mass (density) becomes also possible based on the electro-mechanical coupling exploiting plasma oscillations of a free electron gas (see Figure 2). The negative mass appears as a result of vibration of a metallic particle with a frequency of $$\omega$$ which is close the frequency of the plasma oscillations of the electron gas $$m_2$$ relatively to the ionic lattice $$m_1$$. The plasma oscillations are represented with the elastic spring $$k_2 = \omega_{\rm p}^2m_2$$, where $$\omega_{\rm p}$$ is the plasma frequency. Thus, the metallic particle vibrated with the external frequency ω is described by the effective mass $$m_{\rm eff}=m_1+{m_2\omega_{\rm p}^2\over \omega_{\rm p}^2-\omega^2},$$ which is negative when the frequency $$\omega$$ approaches $$\omega_{\rm p}$$ from above. Metamaterials exploiting the effect of the negative mass in the vicinity of the plasma frequency were reported.

title: Plasma oscillation


text:
Mediterranean fever

Mediterranean fever may refer to:

 * Boutonneuse fever (also called Mediterranean spotted fever, fièvre boutonneuse, Kenya tick typhus, Marseilles fever or African tick-bite fever), a fever as a result of a Rickettsia infection caused by the bacterium Rickettsia conorii and transmitted by the dog tick Rhipicephalus sanguineus
 * Brucellosis, a highly contagious zoonosis caused by ingestion of unpasteurized milk or undercooked meat from infected animals or close contact with their secretions
 * Familial Mediterranean fever, a hereditary inflammatory disorder and an autoinflammatory disease caused by mutations in MEFV gene
 * Mediterranean Fever (film), a 2022 film

title: Mediterranean fever


text:
Tabuk, Saudi Arabia

Tabuk (تَبُوْك Tabūk, ) is the capital city of the Tabuk Region in northwestern Saudi Arabia. It has a population of 594,350 (as of 2022). It is close to the Jordan–Saudi Arabia border and houses the largest air force base in Saudi Arabia.

History
Ptolemy mentioned a place by the name 'Tabawa', at the northwestern corner of Arabia. This name may be a reference to 'Tabuka' or 'Tabuk'. If this is true, the town may be as old as Ptolemy's time. Pre-Islamic Arab poets such as Antra and Nabiqa mention its mountain 'Hasmi' in their poems.

Tabouk became famous for the Expedition of Tabuk in 630 CE, during the period of the Islamic prophet Muhammad. Since then, it remained a gateway of North Arabia. It was visited by Charles Montagu Doughty in 1877.

Tabuk was captured by the Arab forces in 1918, three weeks after the British capture of Damascus. Tabuk became a centre of military activity during the 1991 Gulf War as the city faced threats from Iraqi scuds and air attacks.

Archaeology
The region is rich in antiquities and archaeological sites such as petroglyphs, inscriptions, forts, palaces, walls, Syrian-Egyptian pilgrimage route, and the remains of the Hejaz railway, the main station of which is located in Tabuk.

Hundreds of localities with rock art and inscriptions dating to different chronological periods and ranging from Paleolithic to the Islamic period were recorded at Wadi Dam and the region west of Tabuk. Study of the art revealed rich stylistic variability and both human and animal figures were represented in it. Numerous sites in the area with Thamudic, Greek and Nabataean inscriptions have been found. Tabuk Castle, known as the castle of Aṣ-ḥāb al-Aykah (أَصْـحَـاب الْأَيْـكَـة, "Companions of the Wood"), is mentioned in the Quran. The castle dates back to about 3500 BCE and has been restored many times; the last was in 1652. Several forts and stations were built along the Syrian pilgrimage route, from the Jordanian border to Medina to welcome the pilgrims. The fort consists of two floors built around an open courtyard with a mosque, a well, and a stairway leading to the watch towers used by the guards. Tabuk Castle is considered an archaeological landmark of the region and is open to visitors.

Ain Sukkrah is an ancient ‘spring (عـيـن, 'ayn') dating back to Iron Age times (جَـاهـلـيّـة, 'Ignorance'). There is a legend that during the expedition of Tabuk, Muhammad camped more than ten days near the spring and drank from its water.

The Prophet's Mosque is also known as the Repentance Mosque. It was originally built with mud and roofed with palm trunk trees. It was restored in 1652. Eventually, its complete renewal was ordered by the late King Faisal ibn Abdul-Aziz, along the pattern of the Prophet's Mosque in Medina.

Demographics
In 1950, Tabuk had a population of 12,000. By 2022, this number had grown to 594,350.

Education

Universities include:
 * University of Tabuk
 * Fahad bin Sultan University

Private schools include:
 * British International School of Tabuk
 * International Indian School Tabuk
 * Pakistan International School of Tabuk
 * Philippine International School
 * King Abdulaziz Model schools
 * Tabuk International School
 * Bangladesh International School, Tabuk

Transportation
Tabuk Regional Airport is served by Saudia and other airlines, with both domestic and international destinations.

title: Tabuk, Saudi Arabia


text:
Maturity-onset diabetes of the young

Maturity-onset diabetes of the young (MODY) refers to any of several hereditary forms of diabetes mellitus caused by mutations in an autosomal dominant gene disrupting insulin production. Along with neonatal diabetes, MODY is a form of the conditions known as monogenic diabetes. While the more common types of diabetes (especially type 1 and type 2) involve more complex combinations of causes involving multiple genes and environmental factors, each forms of MODY are caused by changes to a single gene (monogenic). GCK-MODY (MODY 2) and HNF1A-MODY (MODY 3) are the most common forms.

Robert Tattersall and Stefan Fajans initially identified the phenomenon known as maturity onset diabetes of the young in a classic study published in the journal Diabetes in 1975.

Signs and symptoms
MODY is the final diagnosis in 1%–2% of people initially diagnosed with diabetes. The prevalence is 70–110 per million people. 50% of first-degree relatives will inherit the same mutation, giving them a greater than 95% lifetime risk of developing MODY themselves. For this reason, correct diagnosis of this condition is important. Typically patients present with a strong family history of diabetes (any type) and the onset of symptoms is in the second to fifth decade.

There are two general types of clinical presentation.
 * Some forms of MODY produce significant hyperglycemia and the typical signs and symptoms of diabetes: increased thirst and urination (polydipsia and polyuria).
 * In contrast, many people with MODY have no signs or symptoms and are diagnosed either by accident, when a high glucose is discovered during testing for other reasons, or screening of relatives of a person discovered to have diabetes. Discovery of mild hyperglycemia during a routine glucose tolerance test for pregnancy is particularly characteristic.

MODY cases may make up as many as 5% of presumed type 1 and type 2 diabetes cases in a large clinic population. While the goals of diabetes management are the same no matter what type, there are two primary advantages of confirming a diagnosis of MODY.
 * Insulin may not be necessary and it may be possible to switch a person from insulin injections to oral agents without loss of glycemic control.
 * It may prompt screening of relatives and so help identify other cases in family members.

As it occurs infrequently, many cases of MODY are initially assumed to be more common forms of diabetes: type 1 if the patient is young and not overweight, type 2 if the patient is overweight, or gestational diabetes if the patient is pregnant. Standard diabetes treatments (insulin for type 1 and gestational diabetes, and oral hypoglycemic agents for type 2) are often initiated before the doctor suspects a more unusual form of diabetes.

Pathophysiology
The recognised forms of MODY are all due to ineffective insulin production or release by pancreatic beta cells. Several of the defects are mutations of transcription factor genes. One form is due to mutations of the glucokinase gene. For each form of MODY, multiple specific mutations involving different amino acid substitutions have been discovered. In some cases, there are significant differences in the activity of the mutant gene product that contribute to variations in the clinical features of the diabetes (such as degree of insulin deficiency or age of onset).

Diagnosis
The following characteristics suggest the possibility of a diagnosis of MODY in hyperglycemic and diabetic patients:
 * Mild to moderate hyperglycemia (typically 130–250 mg/dL, or 7–14 mmol/L) discovered before 25 years of age. However, anyone under 50 can develop MODY.
 * A first-degree relative with a similar degree of diabetes.
 * Absence of positive antibodies or other autoimmunity (e.g., thyroiditis) in patient and family. However, Urbanova et al. found that about one quarter of Central European MODY patients are positive for islet cell autoantibodies (GABA and IA2A). Their expression is transient but highly prevalent. The autoantibodies were found in patients with delayed diabetes onset, and in times of insufficient diabetes control. The islet cell autoantibodies are absent in MODY in at least some populations (Japanese, Britons).
 * Persistence of a low insulin requirement (e.g., less than 0.5 u/kg/day) past the usual "honeymoon" period.
 * Normal insulin levels (e.g. 2.6-24.9)
 * Absence of obesity (although overweight or obese people can get MODY) or other problems associated with type 2 diabetes or metabolic syndrome (e.g., hypertension, hyperlipidemia, polycystic ovary syndrome).
 * Insulin resistance very rarely happens.
 * Cystic kidney disease in patient or close relatives.
 * Non-transient neonatal diabetes, or apparent type 1 diabetes with onset before six months of age.
 * Liver adenoma or hepatocellular carcinoma in MODY type 3
 * Renal cysts, rudimentary or bicornuate uterus, vaginal aplasia, absence of the vas deferens, epidymal cysts in MODY type 5

The diagnosis of MODY is confirmed by specific gene testing available through commercial laboratories.

Heterozygous
MODY is inherited in an autosomal dominant fashion, and most patients therefore have other members of the family with diabetes; penetrance differs between the types (from 40% to 90%).

Homozygous
By definition, the forms of MODY are autosomal dominant, requiring only one abnormal gene to produce the disease; the severity of the disease is moderated by the presence of a second, normal allele which presumably functions normally. However, conditions involving people carrying two abnormal alleles have been identified. Unsurprisingly, combined (homozygous) defects of these genes are much rarer and much more severe in their effects.
 * MODY2: Homozygous glucokinase deficiency causes severe congenital insulin deficiency resulting in persistent neonatal diabetes mellitus. About 6 cases have been reported worldwide. All have required insulin treatment from shortly after birth. The condition does not seem to improve with age.
 * MODY4: Homozygous IPF1 results in failure of the pancreas to form. Congenital absence of the pancreas, termed pancreatic agenesis, involves deficiency of both endocrine and exocrine functions of the pancreas.

Homozygous mutations in the other forms have not yet been described. Those mutations for which a homozygous form has not been described may be extremely rare, may result in clinical problems not yet recognized as connected to the monogenic disorder, or may be lethal for a fetus and not result in a viable child.

Treatment
In some forms of MODY, standard treatment is appropriate, though exceptions occur:
 * In MODY2, oral agents are relatively ineffective, however most patients are managed conservatively through diet and exercise.
 * In MODY1 and MODY3, sulfonylureas are usually very effective, delaying the need for insulin treatment.
 * Sulfonylureas are effective in the KATP channel forms of neonatal-onset diabetes. The mouse model of MODY diabetes suggested that the reduced clearance of sulfonylureas stands behind their therapeutic success in human MODY patients, but Urbanova et al. found that human MODY patients respond differently to the mouse model and that there was no consistent decrease in the clearance of sulfonylureas in randomly selected HNF1A-MODY and HNF4A-MODY patients.

Chronic hyperglycemia due to any cause can eventually cause blood vessel damage and the microvascular complications of diabetes. The principal treatment goals for people with MODY — keeping the blood sugars as close to normal as possible ("good glycemic control"), while minimizing other vascular risk factors — are the same for all known forms of diabetes.

The tools for management are similar for all forms of diabetes: blood testing, changes in diet, physical exercise, oral hypoglycemic agents, and insulin injections. In many cases these goals can be achieved more easily with MODY than with ordinary types 1 and 2 diabetes. Some people with MODY may require insulin injections to achieve the same glycemic control that another person may attain with careful eating or an oral medication.

When oral hypoglycemic agents are used in MODY, the sulfonylureas remain the oral medication of first resort. When compared to patients with type 2 diabetes, MODY patients are often more sensitive to sulphonylureas, such that a lower dose should be used to initiate treatment to avoid hypoglycaemia. Patients with MODY less often suffer from obesity and insulin resistance than those with ordinary type 2 diabetes (for whom insulin sensitizers like metformin or the thiazolidinediones are often preferred over the sulfonylureas).

Epidemiology
According to data from Saxony, Germany, MODY was responsible for 2.4% of diabetes incidence in children younger than 15 years.

History
The term MODY dates back to 1964, when diabetes mellitus was considered to have two main forms: juvenile-onset and maturity-onset, which roughly corresponded to what we now call type 1 and type 2. MODY was originally applied to any child or young adult who had persistent, asymptomatic hyperglycemia without progression to diabetic ketosis or ketoacidosis. In retrospect we can now recognize that this category covered a heterogeneous collection of disorders which included cases of dominantly inherited diabetes (the topic of this article, still called MODY today), as well as cases of what we would now call type 2 diabetes occurring in childhood or adolescence, and a few even rarer types of hyperglycemia (e.g., mitochondrial diabetes or mutant insulin). Many of these patients were treated with sulfonylureas with varying degrees of success.

The current usage of the term MODY dates from a case report published in 1974.

Since the 1990s, as the understanding of the pathophysiology of diabetes has improved, the concept and usage of MODY have become refined and narrower. It is now used as a synonym for dominantly inherited, monogenic defects of insulin secretion occurring at any age, and no longer includes any forms of type 2 diabetes.

title: Maturity-onset diabetes of the young


text:
Talk:Sidney Morgenbesser

Untitled
From the article:

In 1975, he was named the John Dewey Professor Emeritus of Philosophy.

Why would a 54 year-old be named Professor Emeritus?  21:54, 14 Aug 2004 (UTC)

 * It's incorrect. The title was copied wholesale from the beginning of the Columbia article. Fixed. --Ian 22:55, 14 Aug 2004 (UTC)

 * lists him as Emeritus John Dewey Professor of Philosophy

 * Yes, but that's at the time of his death, having retired from teaching at some point but still holding the Dewey department chair.--Ian 03:51, 15 Aug 2004 (UTC)

 * I see. anthony (see warning) 05:00, 15 Aug 2004 (UTC)

Glad to see this is back after the whole VFD "vanity" fiasco. anthony (see warning) 01:26, 15 Aug 2004 (UTC)

Recreation of deleted content
It was not deleted for vanity, Anthony. It was deleted for copyvio. And, when it comes to that, it still has/had copyvio. We don't get to quote paragraphs from published sources to illustrate our articles. I know you dislike deletion of anything, but the deletion logs show why this article was deleted, and it wasn't due to vanity. Geogre 15:18, 5 Sep 2004 (UTC)
 * I never said it was deleted due to vanity. I'm the one who listed it on the possible copyright infringements page, so I would know why it was deleted.  It was deleted for copyvio (inappropriately since the copyvio was a small part of the article added later, the purpose of my listing was to remove the copyvio not everything) while the VFD vote was still running.  It was listed on VFD for being vanity and I believe it had a majority of votes for deletion at the time it was deleted (see the votes below).  As for it now being copyvio, quoting paragraphs generally falls under fair use. anthony (see warning) 16:08, 5 Sep 2004 (UTC)

Delete Votes
Note that the full discussion appears to have been lost. It was moved to this talk page, which was deleted at some point. http://www.yourencyclopedia.net/Talk:Sidney_Morgenbesser.html has a copy which may or may not be complete.

 * Listed by User:RadicalBender 23 Jan 2004, reason "Looks to be a personal page? A few returns on Google, but the article itself is of no value."
 * Delete. Looks like avanity page. Bmills
 * delete. vanity page bursting with its own importance  LadyPuffball
 * Delete for above reasons. Anjouli
 * Delete. - UtherSRG
 * Delete, vanity --Jia
 * Delete - vanity - (Are Jack and Anthony voting to keep any and all especially vanity pages?) - Texture
 * Delete - Wikipedia is not for vanity pages - Unknown user

Reverted re-insertion of circular reference
152.163.252.167, you restored the circular reference that I had deleted. Before you do that again, please go to the Wikinfo page in question and scroll down to where it says "References: Adapted from the Wikipedia article, "Sidney_Morgenbesser" http://en.wikipedia.org/wiki/Sidney_Morgenbesser, used under the GNU Free Documentation License". See? Our article is the reference for theirs. Therefore, theirs can't be the reference for ours. I'm reverting to my version. Bishonen 14:40, 6 Sep 2004 (UTC)

Actually it's perfectly possible that they both reference each other. The wikinfo version was copied from an old Wikipedia version which has since been deleted. anthony (see warning) 00:14, 7 Sep 2004 (UTC)

01:25, 7 Sep 2004 Bishonen (Reverting to last version by Bishonen, please see Talk page again.)

I don't see anything here. anthony (see warning) 01:28, 7 Sep 2004 (UTC)

Oh, wow, no, I forgot to save what I'd typed here. :-( Thanks, Anthony. This is a short version: I said I couldn't understand what you said about their both referencing each other, which isn't possible. I don't know any more ways to explain it, but I do know it's a bad reference, and I wish you'd take my word for it. Also I don't understand your edit subject line, "I used the Wikinfo article in my edits to this one", because the only edit I see is your reinsertion of the circular reference. Please correct me if I'm wrong, but isn't that all? Isn't it just the same as if you'd reverted to last version  by 152.163.252.167? Bishonen 01:52, 7 Sep 2004 (UTC)

You seem to be assuming that these articles are static. They aren't. Technically each of these articles references an old version of the other one, but this is assumed within the category of references. As for the only edit you see, you seem to be using the history function incorrectly. I have made 7 edits to this article. Have you looked at them all? anthony (see warning) 11:21, 7 Sep 2004 (UTC)

Yes, of course. I can see that you have edited this article seven separate times. The edit title for the seventh and last time was "I used the Wikinfo article in my edits to this one", and I assumed that meant "I used the Wikinfo article in my edits this time". I understand now that you meant you used the Wikipedia mirror article all the time (right? or wrong again?), for all your editing, but I still don't think the edit title made that very clear. I wonder, btw, if that means you were using a mirror of the originally deleted Wikipedia article from January? I mean, you do realize that Wikinfo doesn't add any independent information, I hope. So you had to be either using the deleted article, or the very article you were working on, as a "source". Considering that, do you now see that it's not a good reference ? Bishonen 13:43, 7 Sep 2004 (UTC)

By "this one" I meant "this article". Wikinfo is not a Wikipedia mirror. They do add independent information. In fact, I have an account at Wikinfo where I've added independent information. It is a perfectly good reference. I'm going to re-add it. anthony (see warning) 14:12, 7 Sep 2004 (UTC)

 * Say, that's an interesting system you've got there, Anthony: when you do revert, you keep really quiet about it, and then when you say you'll revert, it doesn't happen. Anyway, I think you definitely should re-add the reference, if it means that much to you. I was only doing the reverting and explaining because I thought it might be helpful (referencing is kind of my field), but I just reached my minimum waste of time limit. Be my guest, go right ahead, I won't revert you. Bishonen 19:19, 7 Sep 2004 (UTC)

I don't revert any article more than once in a day, that's why I hadn't reverted yet. As for my "system", I don't always use the talk page on the first revert, because I assume I am just reverting an honest mistake. Looking at the times, I did use the talk page right after making my revert this time. So I'm not even sure what you're referring to. anthony (see warning) 19:30, 7 Sep 2004 (UTC)

 * You're not. OK, then, your use of the Talk page right after that revert is an example of the system: you spoke, but made no mention that you were making a revert. The example that I had in mind in particular, of course, is when you spoke on VfD/Reverse sexism at 03:25 6 Sept, giving no hint that you were planning to revert the article, and then did revert it very drastically at 03:26. I wish Wikipedia even worked that fast from here. Bishonen 21:07, 7 Sep 2004 (UTC)

When I spoke on VfD/Reverse sexism I specifically said that your addition was POV and original research. How does that give you a hint that I'm going to revert it? Wikipedia doesn't allow POV or original research. anthony (see warning) 19:13, 10 Sep 2004 (UTC)

19:05, 10 Sep 2004 Snowspinner blocked "Anthony DiPierro" with an expiry time of 24 hours (Provocative edit in violation of standing order from arbcom - citing of material on Sidney Morgenbesser that is from a Wikipedia fork that does not reflect material's deletion via VfD.)

 * What is wrong with citing material from a Wikipedia fork? anthony (see warning) 19:16, 10 Sep 2004 (UTC)

Yeah, Yeah, Yeah ...
I do believe it is well-documented (to the extent that the MSM can be called documentation) that Morgenbesser said "Yeah, yeah." In a Usenet thread in 1994, I responded to a similar statement with "Yeah, right," without having known about Morgenbesser. Ever since, I've read variants of both stories, mixing the actors and responses (my favorite one has me as a student in Morgenbesser's class). Jym 10:14, 5 December 2006 (UTC)

Original research banner
I added the original research banner on the top of the page. I have a strong suspicion that a lot of the quotations on this page are from student's own experiences. These really need to have citations, otherwise the unverifiable ones must be removed. JEN9841 (talk) 01:10, 24 September 2009 (UTC)

Delete the article
Unfortunatley, the stated sources does not work, (for the uninitiated; try clicking the first two links; one is dead and the other redirects to the Times main page; e.g., most all of what is written is unverified), and some of the "stories" (i.e. the one about Kant) is a known old joke and "philosopher folk-tale" of dubious truth at the very best. Besides, since when did Wikipedia turn into a repository of "funny stories"? The entire article should be deleted. — Preceding unsigned comment added by 81.227.85.45 (talk) 00:13, 3 November 2011 (UTC)

title: Talk:Sidney Morgenbesser


text:
User talk:Solipsist/archive1

Welcome
Hello, welcome to Wikipedia.

You might find these links helpful in creating new pages or helping with the above tasks: How to edit a page, How to write a great article, Naming conventions, Manual of Style. You should read our policies at some point too.

If you have any questions, see the help pages, add a question to the village pump or ask me on my talk page. I hope you enjoy editing here and being a Wikipedian!

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Again, welcome! - UtherSRG 16:45, 13 Mar 2004 (UTC)

Henry Moore
The trouble with your image placement edit on Henry Moore is that it now looks terrible on a large monitor - say 1600.1200. The second image is inset from the first. The purpose of the DIV arrangement you removed was to ensure the two images are always right justified and one above another. Do you fancy reconsidering your edit? --Tagishsimon

 * You are right, sorry about that: hopefully fixed again now — Actually I fancy rewriting and expanding the article, which would give more space to allow the images to float. And ideally add and image or (replace the Westminster image) to show a pierced reclining figure. -- Solipsist 13:52, 31 May 2004 (UTC)

 * Thanks. Agreed, all we need is for someone with Henry Moore knowledge to come along and provide some more text. And if you're that person, go for it. BTW, I see you are adding Category:Sculptors ... could I suggest you think about the format which has the effect of ordering the links in the categry list in familyname order rather than firstname order. (Or not - your choice, except for Enzo, who is already in that format.) --Tagishsimon

 * No problem. could I suggest you think about the format  - Indeed, unfortunately I only found out about that trick around about the G's, and I'm also now placing the category tags at the bottom of the page. With luck I will go back and fix the earlier tags, but I am out of time today. By the way, theEnzo page is suffering from a bug in the category system which puts white space at the end of the first line. When a picture is right aligned against the first para everything gets rather squished. The work around is to move the picture down to the second para (not good in this case), or put two   at the top of the page (also not brilliant). -- Solipsist 14:10, 31 May 2004 (UTC)

image names
better to not include pixel info in image names, this data is easily obtainable with any image library even webbrowsers...and it makes it more annoying when people will change your image. also, learn about the image syntax, eg thumb|200px

by the way
did you know you can get the names in order in a category by putting tags like this: which specify how they'll be alphabetized? -- Nunh-huh 11:51, 31 May 2004 (UTC)

 * No I didn't - that's useful -- Solipsist 12:02, 31 May 2004 (UTC)

categories
Its a new one on me. It seems we're going to need technical ways to have synonymous categories (Poet and Poets, for example). I can try to delete the page with the superfluous category (I'm not sure if it's possible, but I'll try) and then you can creat a page without a capitalization problem...you'll still have to change it in each individual article till a technical soluntion is forthcoming. - Nunh-huh 11:26, 31 May 2004 (UTC)

 * well, that seems to have gone ok....let me know if I'm wrong! -- Nunh-huh 11:30, 31 May 2004 (UTC)

 * That seems to have done the trick - Thanks. Fortunately I haven't created any tagged articles with the capitalisation. There is a second minor capitalisation issue in that doesn't get automatically promoted to  with the first letter capitalised -- Solipsist 12:02, 31 May 2004 (UTC)
 * I really think we should dispense with case sensitivity for these categories, but that will probably be a refinement at some later time. Meanwhile I'd try to use lowercase except where Uppercase is for some reason essential (Proper Name), etc. -- Nunh-huh 12:05, 31 May 2004 (UTC)
 * Actually I think I was wrong. Capitalisation promotion could be working normally, so it was probably a cache issue that got me before -- Solipsist 12:59, 31 May 2004 (UTC)

Artesian
I regret to inform you that I have listed artesian as a possible copyright infringement. (I know you didn't post the text, of course.) Your diagram is very good, so I thought it would be courteous to let you know of its companion article's demise. It's a shame; but a new, clean version can be posted in a /Temp subpage as per the instructions (and I may do this myself if nobody else gets around to it). In any event, your diagram will not be deleted. Cheers, -- Hadal 09:52, 10 Jun 2004 (UTC)

 * I'd noticed. My drawing was just a reworking of a diagram I saw elsewhere. I thought you had done rather well to spot the text was a copyvio. Rewriting a stub is one solution, but now I look into it more, I have mild doubts as to whether the article should be under the title Artesian in the first place — as your first link makes clear, in a more general sense it should really means 'from Artois'.
 * One solution is to amalgamate the article (and diagram) into Well which is what the 1911 EB does. I could then update the diagram to include a water table well. Trouble is there are also Artesian springs to explain. So alternatively we could move Artesian to Artesian well, explain Artesian springs under the same article and include redirects for Artesian spring and a (one line?) disambig for Artesian.
 * Another interesting wrinkle that your second link implies is that the water table is not a perpendicular surface (as my diagram naively implies), but is probably a sloping or curved potentiometric surface. -- Solipsist 19:23, 10 Jun 2004 (UTC)

Hello
I chuckled when I saw your name -- hadn't noticed you around before. I decided (I have a notably absurd and whimsical sense of humor) to drop by and ask if I was a figment of your imagination, or if you were a figment of mine. ;-) Either way, I think the response will be worth reading.  Happy editing, Jwrosenzweig 23:50, 21 Jun 2004 (UTC)

 * I'm happy to have brightened your day. Smile and the whole world smiles with you - which of course doesn't surprise the solipsist. As to your question, logically I can only give one answer, but I refuse to do so on the grounds that I might incriminate myself :-) -- Solipsist 14:29, 22 Jun 2004 (UTC)
 * Delightful. I hope to see you around more often (or perhaps I will merely will it). :-) Jwrosenzweig 15:52, 22 Jun 2004 (UTC)

Thanks for the flowers
Thanks for the compliments on the Bobby Sands rebalancing. I've just did a brief-ish page on the 1981_Irish_Hunger_Strike, which seemed to me to be sorely missing, and had to edit the links in the Bobby Sands entry afterwards anyway. Thanks for the point on minor editing vs. major editing. I'm new to this so all tips appreciated. Gerry Lynch 23:16, 15 Jul 2004 (UTC)

from carptrash
Hello Solipsist:

I have been including some sources, but most of it is coming from research that I have done over the past 25 years. Much of what I'm posting was done building by building, sculpture by sculpture. Hence the freqent reference to Unpublished Manuscripts  The books that I use are all ones that i have in my own library, seeing as I sort of in an out of the way spot in New Mexico [USA].

But thanks for the feed back. I, sort of like the DJs that you sometimes hear at 3 AM who muse, "I wonder if there is anyone out there hearing this?'" find myself wondering the same. Not that it matters too much. At some point someone will want to know about Charles Keck, and here it will be.

PS
Your line, "Thanks for your stirling work in bolstering the information on American sculptors" has given me my next sculptor, A Stirling Calder ! thanks Carptrash 20:05, 1 Aug 2004 (UTC)

carptrash - again
okay, I did the math [a weak area] and it has only been 22 years. great i just got 3 years younger.

But, seriously, Solipsist, I need your help. i did an entry for Alexander Stirling Calder [and one for his dad, Alexander Milne Clader too] but I spelled Stirling as "StErling" and now i can't chane it.

By the by, I saw you in the history section of Alexander Calder, so you doing sculpture, or was that an accident? Carptrash 03:49, 2 Aug 2004 (UTC)

 * No problem, I've moved the page to Alexander Stirling Calder and updated the two links that point there. 'Alexander Sterling Calder' is still kept as a redirect. Actually it looks like an easy mistake, I found quite a few web sites who use the 'E' spelling, but 500:35 use the 'I'. I've also put some links to the dynasty in the Alexander Calder page. Mind you with three generations of Alexander Calders, they were just asking for trouble.
 * Since you are adding quite a few sculptors, you might be interested in Manual of Style (biographies) which contains various tips for biographical articles. But it is more useful to get the original information in, there are plenty of other people who will come along and fix the Wikilinks later.
 * And yes I've been active in contributing to various sculptor related articles including Alexander Calder (it would be nice to find a Public Domain image of one of his mobiles though).
 * You can find out a little about a person's interests by visiting their user page and following the 'User contributions' link on the left hand panel. -- Solipsist 07:24, 2 Aug 2004 (UTC)

and again
thanks for repairing my stirling error and for saving grandpa from that merger attempt. i am about to try doing some photo stuff when I get my scanner up and running - it arrived by UPS today, but my computer can't find it - and so will probably need close watching. I am printing off ALL the photo tips and suggestions pages, so i really will try.

Carptrash 03:14, 3 Aug 2004 (UTC).

Very Rich Hours
I would go with either Très Riches Heures du duc de Berry or Très Riches Heures, but probally the former, as there may be other manuscripts known as the Très Riches Heures. I would argue that NO medievalist would ever call it "The Very Rich Hours", and so translating the title would be wrong. Thanks for creating the article, by the way, the Très Riches Heures is on of the two most important illuminated manuscripts and we sorely needed an article on it. (The other is the Book of Kells ) Dsmdgold 16:08, 4 Aug 2004 (UTC)
 * OK, I've moved the article and updated most of the links. I'm sure there is a lot more could be said about the book, but the stub is a start. As it happens I was in Dublin a couple of weeks ago and almost saw the Book of Kells, but the queues were rather long and I ran out of time (and at €12 for entry, seeing the Lindisfarne Gospels for free at the British Library looks like better value ;-) -- Solipsist 17:04, 4 Aug 2004 (UTC)

art & stuff
Yes, I can easily be convinced - but right now my wife is jingling the car keys at me - we are off to a Fire Ceremony -a hot night to be sure. Later. . . . Einar

DNA repair
Thanks for the clarification. I am all for criticism which is why I wanted to draw attention to the article. The feedback I received from one objector however bordered on insult.

Cheers prometheus1 08:42, 7 Aug 2004 (UTC)

 * Yes, User:Shibboleth's initial comments were maybe too harsh, but he has appologised several times (often quite diplomatically). I'm sure his comments were well intentioned, and as I've mentioned on your talk pages the FAC objection on writing style is very common, and quite probably correct with respect to the specific requirements of featured article status. -- Solipsist 09:13, 7 Aug 2004 (UTC)

 * Thanks for the mediation, Solipsist. Yes, I approve of clearing up the debate on WP:FAC.  Actually you can delete my objections too, or alternatively reduce the first to just "Dislike writing style.", since if they have validity others should make the same points.  I will be more careful with my objections in the future. --Shibboleth 18:38, 7 Aug 2004 (UTC)

 * I would be delighted to have some genuine constructive criticism in the spirit of making the article more accessible to a wider audience providing that the integrity of the informational content is retained and that it is acknowledge that a certain prerequisite knowledge of biology and genetics is required to make full use of it. prometheus1 04:29, 8 Aug 2004 (UTC)

yes
Thanks - you are doing Audrey proud. And the Wikiholic thing is way toooooo deep for me right now. i need/want to get a couple more pictures out elsewhere yet this morning. then worry about my addictions

title: User talk:Solipsist/archive1