Liqin Zhao

Fazia Derridj

Saffia Djebbar

Christian Bruneau

Henri Doucet
email: henri.doucet@univ-rennes1.fr

sp3-sp3 carbon-carbon bonds formation using 2-alkylazoles and a bromoacrylate as the reaction partners

published or not. The documents may come

Introduction

Several bioactive compounds contain a 2-alkylheteroaryl motif. For example, Isavuconazole is an antifungal, Oxaprozin is a non-steroidal anti-inflammatory drug, Phenoxan is a HIV-1 inhibitor, Bendamustine is used in the treatment of lymphocytic leukemia, and Mipitroban has antithrombotic properties (Fig. 1). Therefore, the discovery of general simple routes to functionalize 2-alkyl-substituted azoles has potential for medicinal chemistry. The palladium-catalysed direct functionalization of several (hetero)aromatics via direct sp 2 and sp [START_REF] Kalyani | For selected examples of formation of sp 2 -sp 3 C-C bonds via intermolecular palladium-catalysed heteroatom-directed direct sp 3 C-H arylations of unactivated C-H bonds with diaryliodoniums or aryl halides[END_REF] C-H bond activation using aryl halides has brought a synthesis revolution in recent years (Scheme 1, top). [1][START_REF] Giri | For reviews on sp 3 C-H bond functionalization[END_REF][START_REF] Kalyani | For selected examples of formation of sp 2 -sp 3 C-C bonds via intermolecular palladium-catalysed heteroatom-directed direct sp 3 C-H arylations of unactivated C-H bonds with diaryliodoniums or aryl halides[END_REF][START_REF] Trost | For the palladium-catalysed activation of alkyl substituents on azole or picoline derivatives[END_REF][START_REF]For palladium-catalysed arylations of 2-methylazoles[END_REF][START_REF] Obora | For the formation of sp 3 -sp 3 carbon-carbon bonds from 2methylbenzoxazole with an iridium catalyst[END_REF] Keeping in mind the results previously obtained for the direct arylation of heteroaromatics, 7 we envisioned the assistance of a palladium catalyst for the functionalization of 2-alkylazoles with a 2-bromomethylacrylate as the coupling partner.

The arylations of 2benzylbenzimidazole, 2-benzylbenzothiazole or 2benzylbenzoxazole using aryl iodides 5a or aryl chlorides 5b as the coupling partners, assisted by Pd-catalysts has been reported by Oshima and co-workers (Scheme 1, top). Recently, Obora et al. reported the iridium-catalysed coupling of 2-methylbenzoxazole with benzyl alcohol for formation of sp 3 -sp 3 carbon-carbon bonds. [START_REF] Obora | For the formation of sp 3 -sp 3 carbon-carbon bonds from 2methylbenzoxazole with an iridium catalyst[END_REF] The functionalization of a 2-methylbenzimidazole, deprotonated with a zinc-pivalate derivative, with ethyl 2bromomethylacrylate as the coupling partner, catalysed by CuCN to afford the 2- [2-(benziimidazol-2-yl)-ethyl]-acrylate derivative has also been described by Knochel et al. (Scheme 1, middle). 8 Catalyst-free reactions have attracted less attention for the functionalization of 2-alkylazoles. The reactivity of 2alkylpyridines with 2-bromomethylacrylate in the presence of K 2 CO 3 as base, but without catalyst has also been described by Kim and co-workers (Scheme 1, bottom). 9a On the other hand, to our knowledge, for 2-alkylazoles, only activated methylene

A R T I C L E I N F O A B S T R A C T

A carbonate base was found to promote the formation of sp 3 -sp 3 carbon-carbon bonds of 2alkylazoles with a bromoacrylate. The reaction tolerates various alkyl substituents and a variety of heteroarenes such as thiazoles, oxazoles or imidazoles.

Keywords:

Thiazoles Oxazole Imidazoles Bromoacrylate Aza-Cope rearrangement groups, such as a 2-benzylbenzoxazole, have been functionalised without catalyst. 9b,9c As the methods for the construction of sp 3 -sp 3 carbon-carbon bonds from unactivated sp 3 C-H bonds of 2-alkylazoles remain scarce, the reactivity of such alkyl groups needed to be investigated. We now report conditions for the functionalization of a 2-ethyl substituent on a thiazole derivative with ethyl 2bromomethylacrylate as the reaction partner, and show the scope of the sp 3 functionalization of 2-alkyl-substituted thiazoles, imidazoles, oxazoles and pyridines.

Scheme 1

Reported examples of sp 3 functionalization of 2alkylazoles or 2-alkylpyridines.

Results and discussion

We initially compared the reaction of 2-ethyl-4methylthiazole and ethyl 2-bromomethylacrylate with and without Pd-catalyst in DMA at 150 °C (Table 1). The presence of PdCl(C 3 H 5 )(dppb) complex in the reaction mixture had no influence both on yield and selectivity of this reaction (Table 1, entries 1 and2). The use of such conditions resulted in the formation of mixtures of the target coupling products 1a and 1b in a 90:10 and 92:8 ratios, respectively. It should be noted that in both cases, no sp 3 C-H bond functionalization at position C4-Me of the thiazole was observed. Lower selectivities in product 1a were obtained using NMP and DMF as the solvents, in absence of palladium catalyst (Table 1, entries 3 and 4); whereas CPME, o-xylene, ethylbenzene and 1,4-dioxane were completely ineffective for this reaction (Table 1, entries 5-7, 9). No reaction also occurred in ethylbenzene or 1,4-dioxane in the presence of 1 mol% PdCl(C 3 H 5 )(dppb) (Table 1, entries 8 and 10). The nature of the carbonate cation has an important influence on this reaction, as both Cs 2 CO 3 and Na 2 CO 3 gave low yields of 1a (Table 1, entries 11 and 12). The low yield obtained with Na 2 CO 3 might be due to its poor solubility in DMA; whereas the higher basicity of Cs 2 CO 3 might be harmful for the reaction. (3 mmol).

The first step of the reaction is certainly the addition of the bromomethylacrylate to the nitrogen atom of the azole derivative to form the N-alkylated species A (Scheme 2). Deprotonation of A in the presence of K 2 CO 3 affords intermediate B. Then, an aza-Cope rearrangement leads to the final product a. [START_REF] Holtgrewe | For mechanism of aza-Cope rearrangement[END_REF][START_REF] Majumdar | For a review on thermal and palladium-catalysed aza-Cope rearrangement[END_REF][12] Br

N Y H R H EtO 2 C N Y CO 2 Et + B EtO 2 C N Y R H K 2 CO 3 a N + Y H R H CO 2 Et Br - + KBr A Scheme 2 Proposed mechanism
Using K 2 CO 3 as base in DMA, (Table 1, entry 1), the scope of the sp 3 C-H bond functionalization using various 2-alkylthiazole derivatives was examined (Scheme 3). From 1.5 equiv. of 2,4dimethylthiazole and 1 equiv. of ethyl 2-bromomethylacrylate, a mixture of 2a and 2b was obtained in a 19:81 ratio. The use of a larger excess of 2,4-dimethylthiazole (3 equiv.) did not allowed to obtain 2a in good selectivity. Again, no sp 3 C-H bond functionalization at position C4-Me thiazole was observed. On the other hand, the reaction of 2-ibutylthiazole or 2ipropylthiazole (1.5 equiv.) with ethyl 2-bromomethylacrylate (1 equiv.) led exclusively to mono-coupling products 3a and 4a in moderate to high yields. Then, we studied the influence of benzene substituents of 2-ibutyl-5-arylthiazoles for such couplings (Scheme 3). Nitro-, chloro-or cyano-substituents are tolerated to afford 5a, 6a and 8a in 51-66% yields. The highest yield was obtained from 2-ibutyl-5-p-tolylthiazole to give 7a in 77% yield. Scheme 3 Scope of the sp 3 functionalization of 2alkylthiazoles. [START_REF]General procedure for the synthesis of 1a-22a: As a typical experiment, reaction of the heteroarene (1.5 mmol), ethyl 2-bromomethylacrylate (0.193 g, 1 mmol), K2CO3 (0.207 g, 1.5 mmol) at 150 o C during 16 h in DMA (4 mL) under argon afforded the corresponding products after extraction with dichloromethane, evaporation and filtration on silica gel. All compounds gave satisfactory 1[END_REF]14 We then studied the reactivity of a set of 2-alkylheteroarenes which do not contain a nitrogen atom at 3-position with and without PdCl(C 3 H 5 )(dppb) catalyst (Scheme 4). As expected, both 2-methylthiophene and 2-n-butylfuran gave no trace of coupling products 9a and 10a. The reactions in the presence of 1,2,5-trimethylpyrrole and 2,4-dimethylisoxazole were also unsuccessful as 11a and 12a were not detected by GC/MS analysis of the crude mixtures. The reaction of 2-ethyl-4methylthiazole with allyl bromide or allyl acetate in order to produce 13a was also unsuccessful (Scheme 4, bottom). Scheme 4 Limitations of the sp 3 functionalization of 2alkylheteroarenes. [START_REF]General procedure for the synthesis of 1a-22a: As a typical experiment, reaction of the heteroarene (1.5 mmol), ethyl 2-bromomethylacrylate (0.193 g, 1 mmol), K2CO3 (0.207 g, 1.5 mmol) at 150 o C during 16 h in DMA (4 mL) under argon afforded the corresponding products after extraction with dichloromethane, evaporation and filtration on silica gel. All compounds gave satisfactory 1[END_REF]14 The influence of the nature of the heteroatom at position 1 of the heteroarene was also examined (Scheme 5). The reaction of 1.5 equiv. of 1,2-dimethylimidazole with 1 equiv. of ethyl 2bromomethylacrylate only gave mono-coupling product 14a in 71% yield. Similarly, 1-benzyl-2-methylimidazole only afforded the mono-coupling product 15a in 65% yield. On the other hand, a mixture was obtained from 1-decyl-2-methylimidazole with the formation of 16a and 16b in a 82:18 ratio. However, the use of a larger excess of 1-decyl-2-methylimidazole gave 16a in 99% selectivity and 78% yield.

From both 2,4,5trimethyloxazole and 2-ethyl-4,5-dimethyloxazole (3 equiv.), again the formation of mixtures of mono-and di-alkylation products 17a:17b and 18a:18b in 47:53 and 45:55 ratios was observed. Scheme 5 Scope of the direct sp 3 functionalization of 2methylimidazoles, 2-methyloxazoles or 2-alkylpyridines. [START_REF]General procedure for the synthesis of 1a-22a: As a typical experiment, reaction of the heteroarene (1.5 mmol), ethyl 2-bromomethylacrylate (0.193 g, 1 mmol), K2CO3 (0.207 g, 1.5 mmol) at 150 o C during 16 h in DMA (4 mL) under argon afforded the corresponding products after extraction with dichloromethane, evaporation and filtration on silica gel. All compounds gave satisfactory 1[END_REF]14 The reactivity of a few 2-alkylpyridine derivatives using K 2 CO 3 /DMA as reaction conditions was also studied (Scheme 6). A mixture of 1 equiv. of ethyl 2-bromomethylacrylate and 1.5 equiv. of 2-methylpyridine gave the products 19a and 19b in a 84:16 ratio. Under similar conditions, the coupling with 2,3dimethylpyridine only gave 20a in a very high yield. A high selectivity in favour of the formation on mono-coupling product 21a was also observed with 2,4-dimethylpyridine.

+ K 2 CO 3 , DMA, 16h, 150 °C a + Br b N Y EtO 2 C N Y R CO 2 Et N Y R CO 2 Et EtO 2 C R' R' R' R 14a
Scheme 6 Scope of the direct sp 3 functionalization of 2methylpyridines. [START_REF]General procedure for the synthesis of 1a-22a: As a typical experiment, reaction of the heteroarene (1.5 mmol), ethyl 2-bromomethylacrylate (0.193 g, 1 mmol), K2CO3 (0.207 g, 1.5 mmol) at 150 o C during 16 h in DMA (4 mL) under argon afforded the corresponding products after extraction with dichloromethane, evaporation and filtration on silica gel. All compounds gave satisfactory 1[END_REF]14 In summary, we have demonstrated that the sp 3 functionalisation of 2-alkyl substituents of azoles with a 2bromomethylacrylate to form sp 3 -sp 3 carbon-carbon bonds proceeds using only K 2 CO 3 as base without catalyst. The reaction selectively promotes the functionalization at C2-alkyl of thiazoles, oxazoles or imidazoles even in the presence of other alkyl substituents. These conditions offer routes for fast access to functionalised alkyl chains at C2 of these heteroarenes.

Figure 1

 1 Figure 1 Examples of bioactive 2-Alkylazoles derivatives.

Table 1 .

 1 Acetates are not suitable bases for this reaction due the side reaction of acetate anion with ethyl 2-bromomethylacrylate which affords ethyl 2-(acetoxymethyl)acrylate (Table1, entry 13). The relatively strong base NaOtBu in o-xylene, with or without palladium catalyst, was also ineffective (Table1, entries 14 and 15). The use of 2.5 equiv. of 2-bromomethylacrylate allowed to obtained 1b in 48% selectivity and in 33% yield (Table1, entry 16). Finally, a lower reaction temperature of 110 °C affords 1a in high selectivity but in very low yield (Table1, entry 17). Influence of the reaction conditions for the coupling of 2-ethyl-4-methylthiazole with ethyl 2bromomethylacrylate.

	Entry Base (equiv.)	Solvent	Ratio	Yield in 1a
				1a:1b	(%)
	1 2	K 2 CO 3 (1.5) K 2 CO 3 (1.5)	DMA DMA	92:8 90:10	80 79 a
	3	K 2 CO 3 (1.5)	DMF	76:24	nd
	4 5 6 7 8 9 10	NMP CPME b o-xylene K 2 CO 3 (1.5) ethylbenzene K 2 CO 3 (1.5) K 2 CO 3 (1.5) K 2 CO 3 (1.5) K 2 CO 3 (1.5) ethylbenzene K 2 CO 3 (1.5) 1,4-dioxane K 2 CO 3 (1.5) 1,4-dioxane	87:13 ------	61 0 c 0 d 0 d 0 a,d 0 c 0 a,c
	11	Cs 2 CO 3 (1.5)	DMA	100:0	trace
	12	Na 2 CO 3 (1.5)	DMA	100:0	12
	13	KOAc (1.5)	DMA	-	0
	14	NaOtBu (1.5)	o-xylene	-	0 d
	15	NaOtBu (1.5)	o-xylene	-	0 a,d
	16 17	K 2 CO 3 (3) K 2 CO 3 (1.5)	DMA DMA	52:48 97:3	33 of 1b e <10 c
	Conditions: 2-ethyl-4-methylthiazole (1.5 mmol), ethyl 2-
	bromomethylacrylate (1 mmol), under argon, 16 h, 150 °C, isolated yields. a 1 mol% PdCl(C 3 H 5 )(dppb). b CPME: cyclopentyl methyl ether. c 110 °C. d 130 °C. e 2-ethyl-4-
	methylthiazole (1 mmol), ethyl 2-bromomethylacrylate (2.5
	mmol), K 2 CO 3

Acknowledgments

We are grateful to the "Chinese Scholarship Council" for a grant to Z. L.


est destinée au dépôt

TRACKING FATAL DROWNINGS IN PUBLIC SWIMMING POOLS : A RETROSPECTIVE MULTISCALE INVESTIGATION WITHIN FRANCE

IntroducMon :

In France, currently we do not have sufficiently precise and comprehensive data to make a valid and reliable diagnosis on the prevelance of fatal drownings. The goal of this study is to clarify the situa>on by tracking the fatal drownings occurring in a sample of French public swimming pools (psp). The existence of fatal pool drownings seriously challenges the chain of supervision that is supposed to neutralize risk of drownings in these facili>es (Soulé & Vignac, 2012). Knowledge about the number of accidents such as drownings occurring in a sports ac>vity is the basis for preven>ng them (Bahr & Krosshaug, 2005). Based on an analysis of secondary sources, this study aims to provide a more accurate and reliable es>ma>on of fatal drownings occurring in French psp.

Method :

The main goal of this study was to explore the current means of repor>ng drowning accidents occuring in French psp. We chose the WHO defini>on of drowning to address the ques>on of drowning without ambiguity and to avoid confusing terminology. Eight unique sources capable of providing informa>on on the number of fatal drownings in French psp were iden>fied and explored over a 10 year period using three geographic scales: (a) the country of France as a whole, (b) the département of Calvados (France being administra>vely divided in 101 départements), and (c) the "agglomera>on community" of Caen la mer (metropolitan government structure grouping a commune-here, Caen and its suburbs). In--depth understanding of the accident repor>ng mechanisms was facilitated by carrying out nine interviews who comprised fire and rescue services department ; Caen Teaching Hospital ; urgent medical aid service ; Department Directorate for Social Cohesion.

Results analysis :

To clarify the analysis, we have modelled the different channels of accident repor>ng. The X--axis is >me--related, while the Y--axis relates to the geographical dimension (see figure below).

We summarize the results of our inves>ga>on into five categories of shortcomings leading to substan>al approxima>on as to the actual number of fatal drownings that may occur each year in French psp. a) Availability of some data (e.g., Caen la mer) mostly depend on stakeholders' good will, since the corresponding procedures are not mandatory, but only discre>onal. b) The CépiDC and SDIS data set suffered from subjec>ve and/or poorly described categories. Because such codes entail quite a bit of interpreta>on, they are not reliable. c) Some data (like those of SAMU 14) were not computerized. Despite its poten>al relevance, lack of digi>za>on and computeriza>on makes this informa>on impossible to exploit especially since the number of reports is considerable. d) Some sources (e.g., InVS, press, Urqual) clearly lack comprehensiveness. e) Noncompliance with the requirements to report serious accidents (e.g., in the case of the DDCS) creates a serious problem with data gathering, availability, and accuracy.

Results :

The various mobilised sources unveiled an intricate complexity. The table below offers a global overview of our gathered data. It discloses important gaps and shortcomings, resul>ng in an es>ma>on of fatal drownings in psp.

PracMcal applicaMon :

Taking into account these analysis, we have made several recommenda>ons. We limited ourselves to the most feasable possibili>es. Out of the eight sources, six were par>cularly likely to benefit from this analysis.

Conclusion :

The collec>on of quan>ta>ve data on fatal drowning in psp was held back by a number of methodological barriers. The rela>ve rarity of fatal drownings in psp, the existence of mul>ple defini>ons of the accident known as "drowning," the diversity of the available emergency services, and the underuse of the sta>s>cal sonware and nomenclatures made available to the emergency services make it impossible, to evaluate precisely, how many people have drowned in french psp. The absences of such a registry prevents learning from experience that has clearly proved effec>ve in other areas of risk preven>on and management. The ul>mate aim of gathering informa>on to be contributed to a na>onal database or clearinghouse on drowning that would include local branches.

Glossary :

CépiDc: Center for epidemiology on the causes of death; DDCS: Departmental directorate of social cohesion (and sport); InVS: French Ins>tute for public health surveillance; SAMU/SMUR 14: Calvados Mobile medical emergency service and resuscita>on; SDIS14: Calvados fire and rescue service; UrQual: Caen teaching hospital (CHU) database.

TRACKING

  Elie Vignac, P Lebihain, B. Soulé To cite this version: Elie Vignac, P Lebihain, B. Soulé. TRACKING FATAL DROWNINGS IN PUBLIC SWIMMING POOLS : A RETROSPECTIVE MULTISCALE INVESTIGATION WITHIN FRANCE. World conference on drowning prevention, Nov 2015, Penang, Malaysia. , pp.58, 2015, World conference on drowning prevention : Program and proceeding. 10.13140/RG.2.1.4463.5609. hal-01228060

1

  Centre de Recherche et d'Innova>on sur le Sport (CRIS EA--647) --Université Claude Bernard Lyon 1 Direc>on des sports --Communauté d'aggloméra>on Caen la mer (France) --elie.vignac@universite--lyon.fr 2 Centre de Recherche en Ges>on (EA--1722) --Faculté des sciences du sport de Poi>ers (France) 3 Centre de Recherche et d'Innova>on sur le Sport (CRIS EA--647) --Université Claude Bernard Lyon 1 (France)


Martine Mazel

William Jacot

Klaus Pantel

Kai Bartkowiak

Delphine Topart

Laure Cayrefourcq

Delphine Rossille

Thierry Maudelonde

Thierry Fest

Catherine Alix-Panabières
email: c-panabieres@chu-montpellier.fr

Frequent expression of PD-L1 on circulating breast cancer cells

Keywords: Circulating tumor cells, PD-L1 expression, Breast Cancer

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

The prognosis of cancer patients, even with localized primary tumors, is mainly determined by the circulation of tumor cells in the peripheral blood from the primary site to distant organs such as bone marrow, liver, lungs, or brain, and the subsequent outgrowth of a largely unknown subset of these cells into metastases in their new microenvironment (Eccles and Welch, 2007). The colonization of distant organs by disseminated tumor cells, resulting in the appearance of clinically detectable metastases, can take many years in breast cancer (Braun et al., 2005) and the mechanisms behind this "cancer dormancy" are largely unknown (Chambers et al., 2002;Goss and Chambers, 2010;Uhr and Pantel, 2011). This stringent selection process together with a potential independent genomic progression of disseminated tumor cells may explain why overt metastases can harbor unique genomic alterations differing from the bulk of the original primary tumor cells (Flatmark et al., 2002;Kang and Pantel, 2013;Riethdorf et al., 2010). Thus, the direct analysis of metastatic cells could reveal important information for systemic cancer therapy targeting metastatic disease (Alix-Panabieres et al., 2012;Pantel et al., 2008). However, biopsy of overt metastases is an invasive procedure limited to certain locations and not easily acceptable in the clinic. Moreover, a recent work has shown that different metastatic sites harbour different genomic aberrations (Gerlinger et al., 2012) and biopsy of one or two accessible metastases may not be representative of the whole metastatic disease biology.

An alternative approach is the analysis of blood samples for circulating tumor et al., 2014). However, the predictive value of PDL1 expression measurements of primary carcinomas seems to be limited. Moreover, there is only a weak correlation in staining between the matched primary tumor and distant metastasis, suggesting that the primary tumor is not an adequate surrogate for determining PD-L1 expression in metastatic sites (Jilaveanu et al., 2014). Tissue heterogeneity in PD-L1 expression in both primary and metastatic sites for a given patient indicates that a single core biopsy might be not sufficient to determine tumor PD-L1 expression (Jilaveanu et al., 2014).

CTCs are currently investigated as predictive biomarker for HER2-targeting therapies (Bidard et al., 2013) et al., 2011). This study belongs to the BMS_PD-L1_onco clinical trial (NCT10660776), which assesses PD-L1 as a biomarker in oncology and hematology.

Cell culture

Mammary cancer cell lines SKBR3 (ATCC® HTB-30™), MCF7

M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT
cm2 flasks at 37°C in a humidified atmosphere conta ining 5% CO2.

CTC enumeration

Seven and half milliliters of blood collected in the CellSave tube were used for CTC detection using the FDA-cleared CellSearch ® system (Janssen, Beerse, Belgium).

Blood samples were processed on the CellTracks Autoprep within 72h. The Briefly, fixed CTCs were first positively enriched via the epithelial cell adhesion molecule (EpCAM) expression and defined as EpCAM isolated intact cells stained positive for cytokeratins (CK8, 18, 19), positive or negative for B7H1 (PD-L1) and negative for CD45 (the exclusion marker specific of normal hematopoietic cells):

CTCs were identified as EpCAM (+) DAPI (+) CK (+) CD45 (-) .

As control group, we analysed in parallel blood samples from 15 healthy controls provided by the regional centre of blood transfusion (Etablissement Français du Sang of Montpellier, France). Tris, followed by a cell disruption step by ultrasonic treatment. Insoluble compounds were removed by centrifugation and the supernatant was collected. The protein concentration was determined using the Pierce BCA Protein Assay Kit (Pierce, Rockford, USA) using BSA as the standard. Proteins were separated by SDS-PAGE using either the Novex XCell Sure-Lock mini system (Invitrogen, Groningen, Netherlands) or the Protean II xi cell (Bio-Rad, Hercules, USA). A Laemmli buffer system and 10% polyacrylamide separation gels were used. The molecular size standard was the peqGOLD protein-marker V (Peqlab, Erlangen, Germany). The proteins were transferred to Immobilon-PSQ membranes (Millipore GmbH, Schwalbach, Germany) using the mini VE vertical electrophoresis system equipped with tank blot transfer units (GE Healthcare, Uppsala, Sweden). The primary antibodies were applied to the membranes at 4 °C wi th gentle agitation over night.

Protein bands were detected using the SignalFire ECL Reagent (Cell Signaling Technology) and X-ray films (GE Healthcare). X-ray films were digitized using the GS-700 imaging densitometer (Bio-Rad). cells. Next, SKBR3 (PD-L1 (+) ) and SU-DHL-4 (PD-L1 (-) ) were analyzed for PD-L1 using the CellSearch ® system with PD-L1 implemented in the 4th channel (Fig. 2D). (high PD-L1 expression) (Figure 3).

Spiking experiments of SKBR3 in control blood

We performed spiking experiments by adding 200 SKBR3 cells in 7.5 mL of blood from healthy donors and detected the breast cancer cells using the CellSearch ® system with the CellSearch ® CXC Kit. These results demonstrated the feasibility to detect PD-L1 (+) tumor cells in blood samples with this technology dedicated for CTC detection. SKBR3 cells could be detected with a recovery rate of 79.5%, which is consistent with the results obtained the standard CTC kit (Riethdorf et al., 2007).

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PD-L1 (+) CTC from metastatic breast cancer patients

Peripheral blood samples from HR (+) , HER2 (-) metastatic breast cancer patients (one male, fifteen females) were analyzed by the CellSearch ® system implemented with the PD-L1 detection by using the optimized conditions described above. For our study, we selected sixteen patients with a CTC count ≥1 using the CellSearch ® system (mean, 254.5; median, 18.5; Range, 1-3146) and 13 of 16 (81.3%) patients with a CTC count ≥5 (mean, 312.5; median, 27; Range, 7-3146), the prognostic cutoff for patients with metastatic breast cancer (Cristofanilli et al., 2004) (Table 2).

Eleven patients out of 16 showed a subpopulation of CTCs expressing PD-L1 (68.8%) scored 1 or 2 (Table 2; Figure 4A). The fraction of PD-L1 (+) CTCs varied from 0.2 to 100% (Table 2). However, this information may also depend on the number of detected CTCs. If only patients with more or equal than 10 CTCs are considered, the fraction of PD-L1 (+) CTCs varied from 0.2 to 50% (Table 2). The intensity of PD-L1 staining varied between patients and within the same blood sample. Analyzing samples with multiple CTCs showed that six patients had CTCs with mixed PDL1 phenotypes (immunoscores 1 and 2), whereas homogeneous PDL1 immunoscores were only found in one patient (Table 2).

As shown in the Figure 4B, we could also easily observe and distinguish PD-L1 (+) leucocytes next to CTCs positive or not for the expression of PD-L1. Leucocytes express CD45, while CTCs are defined in the CellSearch ® system as CD45 (-) .

As negative controls, we tested blood samples from 15 healthy controls and confirmed that none of the samples were positive for CTCs (Data not shown).

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Discussion

In the present paper, we provide evidence that PD-L1 is frequently expressed on metastatic cells circulating in the blood of HR (+) , HER2 (-) breast cancer patients. To our best knowledge, this is the first report demonstrating the expression of PD-L1 on CTCs in any cancer entity. Detection of CTCs expressing PD-L1 means that the patients harbor metastatic tumor cells that may have the capacity to block the immune system. These cells are potential targets for anti-PDL1 therapies. This information is fundamentally different from the detection of shed PD-L1 in the blood serum or plasma, which provides no information on the cellular source of PD-L1.

The sensitivity, specificity and the dynamic range of the PD-L1 MAb that we chose in our study was determined by Western Blot, flow cytometry and immunocytochemical analyses. We tested different mammary cancer cell lines (i.e., MDA-MB-231, MCF-7 & SKBR3) and as PD-L1 was expressed at variable degrees on SKBR3, we selected it as our positive control for the establishment of our novel assay detecting CTCs expressing PD-L1. We could thus established immunoscores for PD-L1 expression on single SKBR3 cells with this anti-human B7-H1 MAb and then validated these scores on blood samples from patients with a HR (+) , HER2 (-) metastatic breast cancer. This strategy has been adapted from previous reports using the CellSearch ® system for immunophenotyping of CTCs (Ignatiadis et al., 2011;Riethdorf et al., 2010).

Despite the fact that we only analyzed a limited number of patients, our results clearly showed that PD-L1 is frequently expressed on CTCs. However, the percentage of PD-L1 (+) CTCs in individual patients varied considerably. In particular, patients with a high percentage of PD-L1 (+) CTCs should be potential candidate for anti-PD-L1 therapy. The established CTC/PD-L1 assay can be used in further trials

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for stratification and monitoring of cancer patients. It should be noted that only EpCAM (+) CTCs were analysed, so the real number of PDL1 (+) CTCs might be even higher. However, we decided to implement the PD-L1 staining into the EpCAMdependent CellSearch ® system because it is still the only automated technical platform cleared by the FDA-USA with a remarkable reproducibility.

The present finding has obvious clinical implications. Immune checkpoint regulators such as PD-L1 have become exciting new therapeutic targets leading to long lasting remissions in patients with advanced malignancies (Shin and Ribas, 2015). However, in view of the remarkable costs and the toxicity profiles (in particular during combination therapy) of these therapies, predictive biomarkers that are able to discriminate responders from non-responders are urgently needed. The development of metastasis in breast cancer (and other solid tumors) can take many years and the metastatic cells may differ from the original cells in the operated primary lesion (Goss and Chambers, 2010). Thus, re-staging of metastatic lesion is required to get realtime information on the molecular characteristics of the actual metastatic cells that are the targets of antibody therapy (not the primary tumor). However, biopsies of metastatic lesions are an invasive procedure with considerable side effects depending on the site of metastasis and, moreover, different metastatic sites can have different molecular characteristics (Gerlinger et al., 2012).

As an alternative, we previously introduced a new diagnostic concept called "liquid

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  cells (CTCs) detection and characterization as a liquid biopsy of the cancer (Alix-Panabieres and Pantel, 2014). It can be performed frequently and might allow real-cancer therapies in individual patients (Alix-Panabieres et al., 2012). Recent reports indicated that CTCs give important complementary information on therapeutic targets and drug resistance mechanisms in carcinoma patients (Alix-Panabieres and Pantel, 2014). CTCs isolated in the peripheral blood are a pool of cells derived from the primary tumor and different metastatic sites and may, therefore, provide a comprehensive real-time picture of the whole tumor burden in an individual patient (Pantel and Alix-Panabieres, 2013). Characterization of tumor cells is of utmost importance. More specifically, PD-L1 expressed in tumors has been recently highlighted to function as a key component of the cancer-immunity cycle by preventing the immune system from destroying cancer cells (Butt and Mills, 2014). PD-1 receptor (CD279) is expressed on the surface of activated T cells and its ligands, PD-L1 (B7-H1; CD274) and PD-L2 (B7-DC; CD273), are expressed on the surface of antigen-presenting cells such as macrophages or dendritic cells. When PD-L1 binds to PD-1, a strong inhibitory signal is transmitted into the T cell, which induces a reduction of cytokine production and a suppression of T-cell proliferation (Brahmer et al., 2012; Chen et al., 2012; Topalian et al., 2012): the immune system is misled by the surrounding cancer cells expressing PD-L1 and does not destroy them. Efforts to restore latent anti-tumor immunity have focused on antibody-based interventions targeting CTL antigen 4 (CTLA-4) and programmed cell death protein 1(PD-1) on T lymphocytes and its principal ligand (PD-L1) on tumor cells(Shin and Ribas, 2015). Ipilimumab, an antibody targeting CTLA-4, appears to restore tumor immunity at the priming phase, whereas anti-PD-1/PD-L1 antibodies restore immune function in the tumor microenvironment. Although ipilimumab can produce durable long-term responses in patients with advanced melanoma, it is associated with related toxicities(Shin and Ribas, 2015). By contrast, antibodies targeting either PD-1 or PD-L1 have produced significant anti-tumor activity with considerably less toxicity(Shin and Ribas, 2015) and are being actively investigated for the treatment of multiple cancers including lung, breast, bladder and renal cancers(Philips and Atkins, 2015). Current efforts focus on registration trials of single agents and combinations in various diseases and settings, as well as on identifying predictive biomarkers of response. Ever since the earliest reports of the effects of PD-1 blockade, PD-L1 expression by tumor cells has been used as potential biomarker to predict a therapeutic response. We recently showed that the level of soluble PD-L1 present in the blood could predict patient's outcome in aggressive Bcell lymphomas (Rossille

  CellSearch ® CXC Kit (Janssen) was used for these specific experiments. It includes a cytokeratin-fluorescein/CD45-allophycocyanin (APC) reagent, leaving the phycoerythrin (PE) channel of the Celltracks Analyzer II® open to incorporate a userdefined PE-conjugate for further characterization of the CTCs. In our project, we improved the CTC detection by using the 4 th channel of the CellSearch ® for PD-L1 expression: we used the anti-human B7-H1/PD-L1 PE-conjugated monoclonal antibody (MAb, Cat N° FAB1561P, R&D Systems, Minnea polis, USA) at a final concentration of 20 µg/mL. The corresponding isotypic control (Mouse IgG1 PE, Cat N° IC002P, R&D Systems, Minneapolis, USA) was used at the same final concentration (20 µg/mL).

  permeabilization kit (Beckman Coulter, Brea, USA) was used to prepare the cells before the addition of the anti-human B7H1 Ab or Mouse IgG1 PE at a final concentration of 20 µg/mL on 0.2 million SKBR3 cells and 0.2 SU-DHL-4. Briefly, cells and both Abs were incubated for 60 min at room temperature in the dark. Cells were then washed with PBS supplemented with 2% fetal bovine serum, centrifuged (600g -5 min) and the cell pellet was recovered with 400µL PBS. Labelled cancer cells were detected by using the Cyan cytometer (Beckman Coulter) and the data analysis was performed using the Kaluza software (Beckman Coulter).Other anti-human B7H1 Abs have been tested: (1) clone 3.1 anti-CD274-PE Ab (ref IM99509, Beckman Coulter), (2) anti-CD274-FITC (ref 558065, Becton Dickinson), and (3) B7-H1-A488 (ref FAB1561G, R&D Systems). As shown by the Figure 1, a direct ELISA on different proteins showed the specificity of the anti-human B7H1 MAb, (Cat N° FAB1561P, R&D Systems; data given by R &D systems). 2.5. Immunocytochemical analyses SKBR3 cancer cells were labelled as described above using the concentration of the anti-human B7-H1 MAb required for the CellSearch ® system (20 µg/mL) and centrifuged gently in a Cytospin™ 4 Cytocentrifuge (Thermo Scientific) on standard glass slides. A drop of the ProLong® Gold antifade reagent with DAPI (Invitrogen, Ref-P36931) was added on the preparation to stain nuclei in blue and slides were mounted. Stained cancer cells were finally observed under a fluorescent microscope (Axio Imager.M1, Zeiss) and automatically analyzed with the software AxioVision Release 4.6.3. The primary anti-PD-L1 B7-H1/PD-L1 MAb (IgG1 Clone #130021, Cat N° MAB1561, R&D Systems) was analyzed versus the Mouse IgG1 Isotype Control (mouse monoclonal, Clone #11711, Cat N° MAB002, R&D System s). As a loading control, anti-alpha-Tubulin (11H10) antibody, from Cell Signaling Technology (Danvers, USA) was used. Protein samples from the cell lines MDA-MB-468, MDA-MB-231, BT-20, PC-3, LNCAP, Du145, SCC25, Cal27, MDA-MB-231-SA, BC-M1, PC-E1 and SU-DHL-4 were analyzed. Cells were harvested in 9.8 M urea, 15 mM EDTA, 30 mM

  For the establishment of a novel assay detecting CTCs expressing PD-L1, the sensitivity, specificity and the dynamic range of the PD-L1 R&D antibody was determined by Western Blot in an array of experiments and cell lines. The PD-L1 R&D antibody was found to detect very low levels of PD-L1, provided only one strong signal at approx. 55 kDa and exhibited a linear increase of the signal intensity proportional to the applied protein amount. For the isotype control very weak or no signal at all was detected in the analyzed cell lines (Figure2A). MDA-MB-231 served as a useful positive control for the establishment of the Western Blot. However, the extraordinary high signal intensity of the PD-L1 R&D antibody frequently resulted in oversaturation of the signals in the Western Blots. To circumvent oversaturation of the signals in subsequent immunofluorescent assays, we therefore focused on the cell line SKBR3, because these cells show a range of levels of PD-L1 expression, which enabled us to develop immunoscores for various degrees of PDL1 on single tumor cells. Next, we analyzed the different breast cancer cell lines SKBR3, MCF-7 and MDA-MB-231 by flow cytometry. All these cell lines were positive for PD-L1 (data not shown). The presence of PD-L1 on SKBR3 cells was confirmed by flow cytometry (Figure 2B) and immunofluorescent staining of cytospins (Figure 2C). The specificity of the staining was demonstrated by the fact that no signals were detected for the cell line SU-DHL-4 (established negative control) and for the isotype control on SKBR3

  anti-human B7-H1/PD-L1 PE-conjugated monoclonal antibody (MAb) from R&D. Other anti-human B7H1 Abs have been also tested at different concentrations with the CellSearch ® system: (1) clone 3.1 anti-CD274-PE Ab (ref IM99509, Beckman Coulter), (2) anti-CD274-FITC (ref 558065, Becton Dickinson), and (3) B7-H1-A488 (ref FAB1561G, R&D Systems). However, a concentration of only 20 µg/mL of the PE-conjugated monoclonal antibody (MAb) from R&D was needed to get an optimal staining, whereas a concentration of 40 µg/mL was necessary for all the other antibodies (data not shown). When we performed additional experiments with the CellSearch ® system dedicated for CTC detection on pure SKBR3, we could observe single PD-L1 (+) SKBR3 tumor cells (Figure 3A) as well as clusters (Figure 3B) of PD-L1 (+) SKBR3 tumor cells. Moreover, we defined a "PD-L1 immunoscore" with three different scores for the intensity of PD-L1 expression by single SKBR3 tumor cells and SKBR3 tumor cell clusters: score 0 (no PD-L1 expression), score 1 (low PD-L1 expression) and score 2

  biopsy"(Alix-Panabieres and Pantel, 2013; Pantel and Alix-Panabieres, 2010).Standardized automated analysis of CTCs for PD-L1 is feasible, as demonstrated in the present investigation. This protocol can be easily expanded to other immune checkpoint molecules and other carcinoma entities. Implementing these liquid biopsy analyses into future clinical trials of checkpoint blockade might not only be useful for CTC analyses performed in real-time before and during the course of the therapy will provide, in addition, important information on the development of resistance.

Figure 1 -

 1 Figure 1 -Human B7H1 Detection in direct ELISA with monoclonal anti-human

Figure 2 -

 2 Figure 2 -Specificity and sensitivity of the anti-human B7H1 MAb (R&D

Figure 3 -

 3 Figure 3 -Detection of PD-L1 expression on SKBR3 cells with the CellSearch ®

Figure 4 -

 4 Figure 4 -CTCs expressing various degrees of PD-L1 detected in blood of HR (+) HER2 (-) metastatic breast cancer patients with the CellSearch ® system.

  characteristics, CTC detection and PD-L1 expression on CTCs. CTCs were detected using the CellSearch ® CXC Kit and stained for PD-L1 in the 4 th channel. PDL1 (+) CTCs were immunoscored for PD-L1 expression: score 1 (low PD-L1 expression) and score 2 (high PD-L1 expression).

Materials and methods 2.1. Patient samples and blood collection

	ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT
	breast cancer before any treatment. Interestingly, we detected a subset of CTCs
	expressing PD-L1 in the blood of patients with metastatic breast cancer using a non-2.
	invasive liquid biopsy. This specific subset represents metastatic cells with a high
	potential to escape T cell-mediated lysis and these cells are therefore the actual After informed consent was given, peripheral blood from patients with hormone
	M A N U S C R I P T receptor-positive (HR + ), HER2-negative (HER2 -) metastatic breast cancer was targets of anti-PDL1 antibody therapy. collected before the start of treatment (CPP number 2011-AOI163-38). Patients were recruited at the University Medical Centre of Montpellier (Department of Medical Oncology) and at the Montpellier Cancer Institute (ICM). Blood was drawn from the arm vein of each cancer patient in specific CellSave® tubes (Janssen, 10mL) for CTC detection. Tubes were then conserved at room temperature and sent to the Laboratory "Detection of Rare Human Circulating Cells -LCCRH" at the University Medical Center of Montpellier where blood samples were processed immediately on A N U S C R I P T M the CellSearch ® system. The BRISQ criteria have been listed in the Table 1 (Moore
	and the same strategy could be used for immune checkpoint blockade therapies such as antibodies to PD-L1. Jilaveanu et al. reported A C C E P T E D A C C E P T E D
	that distant sites have greater PD-L1 expression than the primary tumor (Jilaveanu et
	al., 2014). However, there is, to date, no report on the expression of PD-L1 on CTCs
	in breast cancer or other tumor entities. To investigate whether CTCs express PD-L1,
	we applied the CellSearch ® system to blood samples from patients with metastatic

Acknowledgements

The authors thank Delphine Gueroult for her excellent technical assistance for the CTC detection using the CellSearch ® system. This work was supported by the University Medical Centre of Rennes, an ANR-Roche SA grant (TF), the FEDER and the Region Languedoc-Roussillon (GEPETOS project) (CAP), the Kastner Foundation (KP) and the European Research Council Advanced Investigator grant 269081 DISSECT (KP).


Fidelia Ibekwe-Sanjuan
email: fidelia.ibekwe-sanjuan@univ-amu.fr.

Elaine Ménard

bibliothèques et musées à l'ère du web social et participatif

The term web 2.0 refers to a set of tools that enhance and support user-generated content. Web 2.0 has made possible -and intensified global collaborative mechanisms for the production of content. Since two decades, it has been gradually transforming the traditional web, through a dissemination model mainly structured by service and content providers. In some areas, the participatory and collaborative nature of web 2.0 are blurring old boundaries and hierarchies between professionals and amateurs. Professions related to the creation and dissemination of content and knowledge seem to be particularly affected (publishers, artists, graphic designers, journalists, authors, singers, actors, ...). A massive adoption of participatory web technologies by the general public has led to a reconfiguration and repositioning of professionals and of the stakeholders in many sectors. This special issue (vol 39, n° 3/4) investigates the changes under way in cultural heritage institutions such as libraries, archives, museums, confronted with the widespread use of web 2.0 platforms and practices. The specific questions addressed by the accepted papers are the following:  How do web 2.0 applications transform (or not) the relationship that libraries, museums, and archives have with their public and vice versa?  What socio-professional changes or epistemological repositioning under way among stakeholders of libraries, archives, museums and media are caused by these new digital devices?  How do patrons of libraries, archives and museums view the web 2.0 applications developed by these institutions to enhance their online presence?  Are the concepts of participatory libraries or museums becoming a reality? Are we moving away from past non-participatory practices to new practices that are now participatory?  How will physical institutions (museums, libraries, archives) coexist in the long term, alongside their virtual sites?  Is the institutional and historical distinction between archives, libraries and museums still valid? Is it being challenged by digital phenomena and are the boundaries between them becoming porous due to new needs generated by the public social Web (e.g., "museolibraries")?

The eight papers accepted for publication cover a wide spectrum of institution types and of collections (museum objects, archival documents, library and herbaria collections).

Altogether, they analyse the changes wrought by web 2.0 practices and platforms from a wide range of perspectives: epistemological, historical, sociological, technological and political.

The first paper by Isola Ajiferuke, Jamie Goodfellow, and Adeola Opesade carried out an empirical assessment of the effectiveness of user-generated-contents (UGC) for retrieving documents in library OPACs. The authors compared the performance of user-attributed tags on the Bibliocommons platform to that of controlled vocabulary (keywords and subject terms) to retrieve documents from the OPACs of three different libraries in North America and New Zealand. Their results showed that a large number of items in public libraries were not tagged. Those items that were tagged exhibited a high level of lexical variations (acronyms, abbreviations, slangs, one letter words, spelling variants, language variants). The authors also found that user-tags exhibited a higher level of inconsistency while some tags were promotional in nature, thereby casting doubts about their real authors (users or librarians?). Their findings point to the fact that UGC is too idiosyncratic to be of real use in indexing and retrieving public collections of knowledge and cultural artifacts in any professional capacity. Aggregation of the user tags across more than fifty libraries using the Bibliocommons platform did not seem to produce the saturating effect found in Wikipedia where aggregated opinions (the wisdom of the crowds principle) have helped to resolve conflicting narratives about the object under study.

The paper by Lorri Mon and Jisue Lee also takes an empirical and quantitative approach to assessing social media presence of cultural heritage institutions. Using statistical data analysis techniques, the author analysed the activities of 400 public libraries on Twitter, in the United States, in order to examine how libraries engage with users on social media. The metrics produced calculated several Twitter-related indicators: library profile (how the library presented itself on its twitter account); audience (number of followers); reciprocity (number of users followed back by the library); number of tweets; joining date; authority and influence (presence on lists created by other twitter users).

In a third study, Bérengère Stassin offered an insight into French librarians' perceptions of the importance of library 2.0 for their profession. Through a survey of 37 non institutional blogs maintained by academic and public librarians in France, she analysed major topics found in these blogs. Her results showed that, although library 2.0 was a recurrent topic, it was far from being the most important one in terms of number of dedicated posts. Other issues such as the library itself and copyright were more predominant. She also found that librarians employed different discursive genres to write about library 2.0: opinion posts on what role social media should have for libraries as institutions; accounts of initiatives or experimentations; book reviews and descriptions of tools were among the discourse genres found. Globally, she found that librarians were pessimistic about the inertia gripping French libraries which makes them very slow to adapt professional training and culture to the rapidly changing digital environment and social practices of their patrons.

The fourth paper by Manuel Zacklad and Lisa Chupin shed and interesting and pertinent light on the participatory practices induced by digital platforms of herbaria (collections of dried plants). To characterise the forms of cooperation between institutional curators and amateurs on these platforms, the authors observed the modalities of the participation deployed on these platforms and evaluated possible epistemological and socio-professional repositionings of the professional curators. The authors observed that even for herbaria sites that strongly encourage participation, users participation is overseen by curators and biodiversity specialists. The most active contributors do not have the rights to arbitrate divergent opinions and solve litigious cases based on their experience. This prerogative still lies in the hands of the institution that owns the herbarium collection and digital platform. This form of supervised participation is largely predominant and does not engender the emancipation and liberating properties attributed to web 2.0 platforms nor does it satisfy the epistemic drive of the contributors. The objectives of the professional curators and the collection owners seem to be to avoid interpersonal cooperation amongst contributors in order to resort to a regulated coordination. The authors conclude that the digitisation of natural history collections has not been accompanied by leveraging the digital to facilitate the emergence of new and heterogeneous actors that can renew the old forms of authoritative mediation. The result could be disillusion and loss of some of the most active contributors of these participatory platforms since the emancipating and liberating promises of online participation are not met.

The fifth study by Florence Andreacola, Marie-Sylvie Poli and Eric SanJuan shed further light on how museums are grappling with the injunction to « participate » that lies at the heart of the web 2.0 paradigm. Based on a case study of a French museum, the authors developed both quantitative and qualitative techniques (surveys, semi-structured interviews) to analyse the perception that virtual and physical visitors had of museums and their activities and how museum visitors used digital technologies to share their museum experiences with others. Their results showed that visitors used digital technologies mostly to prepare their visit but that during the visit, they respected the solemnity of the physical museum. They also preferred to share impressions of their visit orally, in face to face communications, rather than using digital media. Their study concluded that museums may be at a turning point where they cannot afford not to have an online presence since this has become mediation spaces for prolonging museum experiences. However, the online presence and use of digital media by museums need to be negotiated carefully if they are to continue fulfilling all their missions.

The sixth paper by Cheryl Klimazewski addresses another question raised by the special issue concerning the solidity of the historical boundaries between archives, libraries and museums faced with the technological advancements of the last decades. Backed by an international literature review, the author was able to demonstrate that historically, there was more convergence and collaboration between libraries, archives and museums (LAMs). However, changes in institutional culture and societal needs for increased literacy rather than technological advancement have led to a "split", with each institution drifting apart and becoming a "type". Currently, LAMs are being "lumped" together in the literature due more to policies and strategic vision of an "integrated cultural web" rather than to a real convergence of professional practices. Nevertheless, increased digitisation of knowledge and cultural heritage artifacts has been a strong advocate for an integrated curriculum for training LAM professionals which should lead to more collaboration and convergence. The level to which practices across domains can or should converge is still a matter of current debate. Finally, the author reminds us that technological advancement is not neutral and that digitisation can lead to loss of memory of the original objects that have been transformed into bytes, subsequently leading to a depreciation of the social function and value of LAM institutions, given that more and more of their "objects" are available on the Internet and can be viewed from anywhere.

The seventh paper by Amy Williams brings some practical answers to the issue of lumping or split of LAMs raised by Cherly Klimazewski. Amy Williams explored how archival practices are evolving in the web 2.0 era with the emergence of the concept of "archives 2.0" and how the culture of collaboration and participation have spread to other cultural heritage institutions such as libraries and museums, hence to three institutions types that were hitherto held to be separate. She examined the processes and modalities through which various bodies -be they professional heritage institutions like archives or museums or simply associations and foundations, preserve cultural heritage artifacts. Like in Klimazewski's paper, Williams observed that the digital phenomenon is an enabler of collaboration and participation. It boosts collaboration between information professionals (archivists, librarians) but also between professionals and the general public as well as helping to create communities around the preservation and sharing of specific historical collections. Digitisation has also brought about the blurring of many frontiers in the archival field. For instance, when describing a historical object, the creator of the archival description is at the same time the "provenance" (source) and "custodian" of the digital collection, this rarely happened when archives were mainly in physical form. Current institutional policies in the United States augur for an increase in collaboration and convergence between archivists and other cultural heritage institutions.

Finally, Chern Li Liew, Shannon Wellington, and Gillian Oliver's study address how web 2.0 platforms and practices affect the relationship between libraries, museums and archives, and their patrons. They address one specific question raised by the special issue concerning to what extent the concepts of participatory libraries or museums are becoming a reality and whether we are moving away from non-participatory past practices toward new practices that are more participatory. Their study goes a long way in debunking the myth of the power of social media and web 2.0 practices in transforming social and professional practices in cultural heritage institutions. Chern Li et al. began their study by a much needed literature review of the origins of the "2.0" ideology within the cultural heritage and preservation institutions. They showed how a user-centric approach to archives, promoted in the 1980s, predated the actual web 2.0 technologies that can enable it, and hence predated the emergence of the concept of archive 2.0. They also recalled that the post-modernist criticisms of traditional archival practices as being steeped in a positivist-objectivist stance serving only the interests of dominant groups who claim to portray the « Truth » is a more powerful argument for advocating a more pluralistic approach to cultural heritage preservation that incorporates the viewpoints of diverse stakeholders including the public. How this is to be achieved practically, whether with web 2.0 platforms or not, remains an open question. Likewise, their literature review of the concept of library 2.0 confronted different viewpoints about how libraries should embrace the web 2.0 phenomena and underscored the fact that, although a lot has been written about the need for libraries to move to a more participatory approach, implementing this and crowning it with success is far from straightforward. Moreover, the use of web 2.0 platforms like blogs and wikis has not led to a real epistemological or sociological shift in the realm of library work and the way librarians relate with their patrons. Furthermore, backed by empirical evidence in the form of a survey of cultural heritage institutions's use of social media (SM), Chern Li et al. analysed hundreds of responses from a varied group of institutions (libraries, archives) across the world. They were thus able to analyse the reasons why professionals adopted or not social media (SM), the difficulties they encountered in trying to use them. One of the reasons given by librarians for not developing SM policy is very revealing: the non-hierarchical nature of social media "does not sit well within the very hierarchical structure" of these institutions imbued with a "command and control" philosophy. Transitioning to a SM platform will then entail an epistemological repositioning of the senior management "hierarchy" who will have to let go of some of its commands. This could have both positive and negative consequences for the institution. On the positive side: social media can be used in libraries and archives to « engage new communities of users, provide powerful tools for advocacy and outreach and democratize institutional management of cultural memory". On the negative side « the affordances of social media may impact negatively on institutional branding, alienate users and compromise information dissemination ». Currently, the main motivations for libraries and archives to be present on SM seem to be more of an expectation: to appear tech-savvy and to be aligned with the technological practices of their patrons, to be present "where the users are". The real participatory practice which will be transformational will be when libraries and archives accept to integrate UGC into their collections. Their findings indicate that cultural heritage institutions (libraries, archives and museums) are still stuck in the classical "one way broadcast model of the early world wide web » and that « although there has been enthusiastic uptake of social media tools, there is little evidence of the current use being transformative. »

The eight papers published in this special issue arrive at converging conclusions: that the oft-proclaimed liberating and empowering capacity of web 2.0 for the general public has not yet taken professional practices in the cultural heritage institutions by storm whereas it has caused a blurring of frontiers between amateurs and professionals in e-commerce, politics or journalism where UGC, user feedback and the entry of new players have upset old hierarchies, strongholds and professional practices. Web 2.0 is yet to challenge the authoritative role of librarians, archivists and museum curators as the main custodians and authors of the narrative on world cultural heritage. Although some cultural heritage institutions have experimented successfully with some form of participation and collaboration with the public (cf. Library of Congress Flickr experience1 , the Normandy archives crowdsourcing of the tagging of 3000 photos of the first world war on Flickr2 ), it is still the professionals that have the final word on which UGC is integrated into the official narrative of knowledge and cultural heritage artifacts. Hence, the authoritative role of controlled vocabularies and of librarians, archivists and museum curators appears to resist in front of the participatory ideology of web 2.0.

French version

Le terme « web 2.0 » renvoie à un ensemble d'outils web, ayant comme dénominateur commun la création de contenus par les utilisateurs. Le web 2.0 a intensifié et rendu possible, à une échelle planétaire, des mécanismes collaboratifs pour la production de contenus. Il s'agit d'une transformation progressive du web traditionnel qui, pendant près de vingt ans, reposait sur un modèle de diffusion, principalement structuré par les prestataires de services et de contenus.

Cette capacité participative et collaborative du web 2.0 peut dans certains cas gommer d'anciennes frontières ou hiérarchies entre professionnels et amateurs dans différents secteurs d'activité. Les métiers liés à la création et à la diffusion de contenus et des savoirs semblent être particulièrement concernés (éditeurs, artistes, graphistes, journalistes, documentalistes, veilleurs, bibliothécaires, archivistes, infos-managers, etc.). L'adoption massive de la technologie du web participatif par le grand public conduit à une reconfiguration et à un repositionnement des acteurs dans ces secteurs. Ce numéro thématique (vol. 39, n° 3/4) vise à sonder des mutations ou transformations en cours au sein des institutions et acteurs des bibliothèques, archives et musées du fait de la généralisation des pratiques numériques du type web 2.0. Les contributions tentent de répondre aux questions suivantes :  Comment les dispositifs numériques du web 2.0 transforment-ils (ou non) la relation que les bibliothèques, les musées, et les archives entretiennent avec leurs publics et viceversa ? Jusqu'à quel point les concepts et phénomènes de bibliothèques ou muséologie participatives sont-ils devenus des réalités ?  Sommes-nous dans un cadre de rupture avec des pratiques anciennes qui ne seraient pas participatives et de nouvelles pratiques qui le seraient devenues ?  Quelles modalités sont trouvées pour faire coexister à la fois des lieux physiques (musées, bibliothèques, archives) et leurs formes virtuelles ?  La distinction institutionnelle et historique entre archives, bibliothèques et musées est-elle mise au défi par le numérique ? Les frontières entre eux sont-elles en train de devenir poreuses du fait de nouveaux besoins de publics engendrés par le web social (des « museo-bibliothèques ») ?  Quelles évolutions socioprofessionnelles ou repositionnements épistémologiques sont en cours au sein des acteurs des bibliothèques, archives et musées et sont-elles provoquées par ces nouveaux dispositifs numériques ?  Quelle réception le public réserve-t-il à ces applications innovantes de technologies de web 2.0 en bibliothèques, archives et musées ?

Les huit contributions acceptées portent sur différents aspects de ces changements : épistémologique, technologique, sociologique et politique.

Le premier article par Isola Ajiferuke, Jamie Goodfellow et Adeola Opesade étudie les caractéristiques et l'efficacité des étiquettes (tags) dans le contexte des catalogues de bibliothèques d'accès public en ligne (OPAC). Les résultats de leur étude démontrent qu'un grand nombre d'oeuvres ne reçoivent aucune étiquette, sinon un ou deux mots en guise d'étiquettes, relativement au sujet de l'oeuvre. Les auteurs concluent leur article avec quelques recommandations à Bibliocommons afin d'améliorer le repérage.

La deuxième étude par Lorri Mon et Jisue Lee évalue les profils et les activités de 400 bibliothèques publiques sur Twitter, de manière à explorer la nature changeante de la présence de la bibliothèque en ligne, de même que les nouvelles tendances du web 2.0 et les modèles émergeants de mesure et d'évaluation. Les résultats de cette étude présentent les activités, l'influence et les pratiques d'autoprésentation des bibliothèques dans Twitter et donnent un aperçu de la manière dont les bibliothèques interagissent avec les utilisateurs dans les environnements de micro-blogues en ligne.

Bérengère Stassin présente les résultats d'une étude consacrée aux blogues de bibliothécaires français tenus de manière non institutionnelle, qui sont aujourd'hui reconnus comme un moyen de diffusion de l'information professionnelle. Son analyse montre que l'information professionnelle est traitée selon différents aspects : la présence en ligne des bibliothèques, l'interaction avec les usagers, le développement de nouveaux services et la formation du personnel. Cette étude met aussi en lumière que les publications (posts) appartiennent à différents genres discursifs tels que le billet de point de vue, le compte-rendu d'expérience, la note de lecture ou encore le descriptif d'outils.

Manuel Zacklad et Lisa Chupin nous livre une étude fine et un décryptage pertinent des modalités de participation de la « foule », induites par les plateformes numériques des sites des herbiers (collections de plantes séchées). Les auteurs ont observé l'activité des internautes invités à participer sur plusieurs sites des herbiers numériques en France et à l'étranger. Ils analysent ensuite les implications de ces formes de participation sur le positionnement épistémologique et socio-professionnel des conservateurs des herbiers. Les auteurs constatent que même si les sites des herbiers qui s'inscrivent davantage dans le modèle participatif du crowdsourcing encouragent une plus grand participation des internautes, cette participation reste encadrée, les contributeurs les plus actifs qui ont la capacité d'animer la communauté ne disposant pas davantage de pouvoir pour valider les contenus en cas d'avis divergents ou de litiges. Cette compétence d'arbitrage demeure aux mains de l'autorité institutionnelle détentrice de la collection et du site. Ainsi, cette forme de participation encadrée n'offre pas des propriétés émancipatrices vantées du web 2.0 et ne satisfait pas les pulsions épistémiques des contributeurs. L'objectif des concepteurs de ces sites semble être d'éviter la coopération interpersonnelle et de recourir le plus possible à la coordination réglée. Les auteurs concluent ainsi que la numérisation des collections d'histoire naturelle ne s'est pas encore accompagnée par l'utilisation du numérique pour faciliter la mise à contribution d'acteurs hétérogènes qui permettront de renouveler les modes de médiation traditionnels. Faute de pouvoir satisfaire pleinement leur pulsion épistémique, certains sites « participatifs » risquent simplement de perdre leurs contributeurs les plus actifs.

L'article de Florence Andreacola, Marie-Sylvie Poli et Eric SanJuan s'attache à l'étude des usages des TICs par les visiteurs d'un musée. Pour étendre sa présence et inviter le public à participer, les collections des musées nourrissent différents artefacts museaux (exposition, catalogues, animations culturelles). Avec le numérique, le site Internet et les plateformes du web participatif deviennent d'autres supports et lieux de médiation muséale. Les auteurs étudient comment l'infrastructure informatique déployée par les musées facilite ou freine ces formes numériques d'expériences muséales. A l'aide de méthodes d'enquêtes quantitatives et qualitatives (questionnaires, entretiens semidirigés), les auteurs analysent, auprès des visiteurs physique et virtuel d'un musée de société en France, la perception qu'ils ont du musée et de ses activités et les quels moyens par lesquels ils partagent leurs impressions (site web, réseaux sociaux tel Facebook). L'analyse des entretiens a montré que les gens se servent des technologies numériques pour prendre connaissance des activités du musée -Internet servant pour s'informer et pour préparer la visite et les réseaux sociaux servant pour décider d'aller à l'exposition. Durant la visite, les visiteurs respectent l'aspect solennel des lieux et préfèrent partager leurs expériences de visite oralement, par des échanges humains plutôt que par des dispositifs de médiation technique. Leurs résultats tendent à montrer que si les musées peuvent résister à l'injonction à participer du web 2.0 qui pourrait être passagère, ils ne peuvent écarter les plateformes numériques dans leur stratégie de rencontre avec le public car celles-ci sont devenues des espaces de médiation et de médiatisation des expériences muséales. Les auteurs concluent que les musées pourraient être à un tournant qu'ils doivent négocier avec habileté, s'ils veulent continuer à remplir au mieux toutes leurs missions. L'étude de Cheryl Klimaszewski explore les tendances de la convergence dans le contexte des archives, bibliothèques et musées. Une revue de littérature exhaustive a été menée afin de relever les influences des pratiques institutionnelles et professionnelles relatives à la convergence, la divergence et l'amalgame des archives, bibliothèques et musées. L'auteure présente les nombreuses lacunes avérées, dont la sélection pour la numérisation documentaire, la déconnexion entre les décideurs, les bailleurs de fonds et les praticiens, l'absence d'études exhaustives des usagers des collections numériques et le manque de vision au sujet du rôle des technologies émergentes. Amy Williams examine le monde des dépôts numériques et la manière dont l'avènement du web 2.0 a encouragé la hausse de la participation, la collaboration et le développement communautaire. Les trois types de dépôts numériques abordés comprennent les projets d'histoire numériques, les archives communautaires et les collections numériques. L'auteure conclut que ce changement vers l'expérience communautaire dans les dépôts numériques dépasse le seul domaine des archives et des bibliothèques.

Enfin, Chern Li Liew, Shannon Wellington et Gillian Oliver présentent les résultats d'une revue de littérature menée au sujet de la nature transformatrice des technologies en général et plus spécifiquement, de celle des médias sociaux. Les résultats de leur étude mettent en lumière l'écart qui existe entre la vision de l'utilisation des médias sociaux par les institutions du patrimoine culturel et la réalité de leur mise en oeuvre.

http://blogs.loc.gov/loc/2008/01/my-friend-flickr-a-match-made-in-photo-heaven/

https://www.flickr.com/photos/photosnormandie/


Armando Martinez
email: armando.martinez.rios@univ-poitiers.fr

Noël Richard
email: noel.richard@univ-poitiers.fr

Christine Fernandez-Maloigne

Colour Contrast Occurrence matrix: a vector and perceptual texture feature

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

Colour and texture are two visual characteristics highly important in low level image processing applications. However the definition of texture is linked to a human semantic meaning. [START_REF] Vácha | Colour and rotation invariant textural features based on markov random fields[END_REF] Researches from the point of view of human perception by Julesz, [START_REF] Julesz | Visual pattern discrimination[END_REF] Caelli 3 and Landy [START_REF] Landy | Visual perception of texture[END_REF] have shown that texture assessment can be approached from local, structural approach or a combination of both. So, there is no formal mathematical definition for texture; [START_REF] Aptoula | Extending morphological covariance[END_REF] while the color rendering can be define mathematically. [START_REF]Foundations of Vision[END_REF] Haralick establishes the bridge between the physical and the computer point of view using statistical analysis between two pixels through the cooccurrence notion. [START_REF] Haralick | Textural features for image clasification[END_REF] Later Ojala extends the study to the neighborhood using local binary patterns. [START_REF] Ojala | A comparative study of texture measures with classification based on feature distributions[END_REF] The initial idea, expressed for intensity images, was extended to colour by different researchers, which have tried to mix the color and texture separately, 910 or in parallel, [START_REF] Arvis | Generalization of the co-occurrence matrix for colour images: Application to colour texture segmentation[END_REF] . [START_REF] Porebski | Lbp histogram selection for supervised color texture classification[END_REF] Many approaches are evaluated in databases where lighting conditions are controlled and therefore there is no significant changes in the appearance of texture. The invariance conditions of acquisition of an image are important since the appearance of natural textures vary significantly with changes in lighting. [START_REF] Burghouts | Material-specific adaptation of color invariant features[END_REF] Industrial or artificial textures have periodic structures that hard to change even if not, they can be seen from the same angle. The natural textures may not have any detectable periodic structure. However they are random, but repeated resulting in an apparent texture. [START_REF] Backes | Color texture analysis based on fractal descriptors[END_REF] Inside this work, we propose a new vector processing for colour texture characterization, the color contrast occurrence matrix C 2 O. This new texture feature is based on the colour difference assessment. To be link to the human perception, the colour difference is expressed using a perceptual distance expressed in CIEL * a * b * and two angles characterizing the chromaticity and darker or lighter direction. [START_REF] Martinez Rios | Alternative to colour feature classification using colour contrast ocurrence matrix[END_REF] Our paper presents the results of evaluating the vector C 2 O to changes in lighting, orientation and intensity of the light source. Varying spectrum and texture rotation, simulates different day light or artificial illumination 1 and allow to explore the impact on our 3D representation of the texture variations. In a second time, we show the results of the classification of C 2 O against other approaches as cooccurrence matrices and local binary patterns adapted to colour domain.

METHOD

Colour Contrast Occurrence Matrix definition

Our feature express the probability to have a specific colour difference between 2 pixels separated by a spatial vector. This spatial vector is defined classically by a spatial distance and orientation. The colour difference is expressed in CIEL * a * b * through a perceptual distance ∆E and two angles. The first angle is defined on the ab plane characterizing the chromatic orientation of the colour difference. The second angle is defined between the colour difference vector and the ab plane characterizing if the difference vector expresses a darker or lighter difference. So the Colour Contrast Occurrence (C 2 O) is defined by:

• be two pixels location: p ci and p cj .

associated to their colour coordinates

(C i , C j ), expressed in CIEL * a * b * , -with || ----→ p ci , p cj || = d and ( -→ Ox, ----→ p Ci p Cj ) = θ. • Then the Colour Contrast Occurence Value ------→ Λ(C i , C j ) is: -----→ Λ(c i , c j ) : prob -----→ Λ(c i , c j ) = -→ Λ χ , (1) with||
-----→ Λ(c i , c j )|| = ∆E χ and ( -→ Oa, --→ c i c j ) = (α, β) = -→ Λ χ .

Feature from the Colour Contrast Occurrence Matrix

Albuz et al. carried out a quantization from CIEL * a * b * space making a book of codes in order to reduce the information contained in a database. [START_REF] Albuz | Quantized cielab* space and encoded spatial structure for scalable indexing of large color image archives[END_REF] Following this direction, we propose to construct the texture feature directly from the Colour Contrast Occurrence matrix. As the C 2 O matrix creates a cloud of occurrences centered around the origin, the proposed features is the spherical quantization from center to the border of the C 2 O cloud.

Sig C2O (I) = h ∆iαj β k = prob ∆ i ≤ -----→ Λ(c i , c j ) < ∆ j + ∆E step , (2)
with π 2n α (j) ≤ α < π 2n α (j + 1) and 0 ≤ β < π n β (k + 1),
where ∆E step , n α and n β are contrast norm, chromatic and lightning steps respectively.

RESULTS AND DISCUSSION

C2O Stability on illumination, rotation and view point changes for ALOT database

ALOT is an impressive colour image collection of 250 distinct rough textures, acquired by 4 different colour camera (c = 1, . . . , 4). For each image and camera, six illuminations are considered (I = (1, 2, 3, 4, 5, 8)) and 4 rotations (r = 0 o , 60 o , 120 o , 180 o ). [START_REF] Hossain | Texture databases -a comprenhensive survey[END_REF] Three image sizes are proposed: full resolution (1536×1024), half resolution (768 × 512) and quarter resolution (384 × 256) pixels. The colour resolution is expressed on 24 bits.

Images in the figure 1 show natural texture of grass in which only the illumination has changed (same camera (c = 1), the same viewpoint (r = 0 o )). Firstly, if we approximate the C 2 O shape as an ellipsoid, few shape differences appear. The main ellipsoid orientation is organized around the L axis. Among the illuminant nature, the lightning difference varies from important (Illumination 1, due to a large range of contrast) to less important (Illumination 4). This fact is in adequation with our perception. In a more accurate observation, the illuminant variations induce change in the assessment of the chromatic difference observed on the ab plane, that is also in adequation with the physical construction of the observed scene as a multiplication of the illuminant spectrum by the reflectance spectrum. Inside this first study, we can take interest also to the bounding-box volume of the ellipsoid as a measure of the lightning impact on the scene. The second experiment assess the impact of the orientation changes on the C 2 O feature. We select the same image than previously, selecting the illumination I = 1. The selected orientation to compare are (r = 0 o , 60 o , 120 o , 180 o ). The results in figure 2 show that the C 2 O shape is slightly modified, even if the volume measure is well preserved. The main ellipsoid axis keep the orientation among the L axis. A more accurate observation indicate that some problems appear in the ALOT process for the rotation change, The transform is not limited to a simple rotation but include also a translation. This problem is visible for the rotation r = 120 o , where the background appear and is not present on the others images. Consequently the C 2 O shape is impacted by this texture part, that is not present in the other images.

C2O Stability on illumination and view point changes for OUTEX database

To assess the impact of lightning change in the OUTEX case, we use the TC0014 suite including 68 colour texture images of size 746 × 538 pixels of 24 bits acquired under three types of illumination: 2300K horizon sunlight denoted as "horizon", 2856K incandescent CIE A denoted as "inca" and 4000K fluorescent TL84 denoted as "TL84". [START_REF] Oulu | Outex texture database[END_REF] Figure 3 show the used illuminant.

In figure 4 we show the important variations on the content perception induced by the lightning changes. Among the illuminant, the canvas appear violet, blue or close to a brown in function of the spectral multiplication between the light spectrum and the reflectance spectrum of the canvas. These differences are explained by the variations in the red part of the spectra. In a first approximation, we expect that the C 2 O matrix rotates around the L axis. This fact is obtained between the INCA and TL84 cases. As the HORIZON illuminant present a relative spectral power close to 550nm, as the INCA illuminant, the two ellipsoid have the same orientation. The difference are due to the differences in the spectrum shapes. For a more complex texture, as in the case of CANVAS 20 (fig. 5), the same interactions between the lightning changes and the texture generate the same C 2 O modifications, even if the colour content is more complex. Such result induces the ability to identify the light modifications between two textures. In a second level of observation, the C 2 O matrix are sufficiently different to allow the discrimination between the two CANVAS textures.

inca TL84 horizon

Inside the new extended OUTEX, the set TC0030 provides 68 images of colour texture of 128 × 128 pixels with different rotation angles (0 o , 5 o , 10 o , 15 o , 30 o , 45 o , 60 o , 75 o and 90 o ). The illumination conditions are the same for the 12240 images. [START_REF] Lille1 | Extended outex texture classification test suites[END_REF] The graphic 6 shows the texture CANVAS 0 with rotations of 0 o , 5 o , 10 o , 15 o . As in the ALOT case, the transformation applied to the image is not a pure rotation, and a translation appears also. Unfortunately the texton size is close from the image size so the translation induces some texture feature modifications. Nevertheless the C 2 O shapes are similar and the obtained volumes are in the same range(outside the second case (5 o )).

Illumination and viewpoint direction performance

After this subjective comparison, we develop an objective test to assess the feature stability among different variations. To do it, we use the classification schema suggested by Arvis. 11 The table 1 shows the correct classification percentage between C 2 O and approaches invariants to lighting changes as cooccurrence (GLCM) and local binary pattern (LBP). These approaches including the colour and texture information in parallel (Cross-Channel Marginal Approach). [START_REF] Martinez Rios | Alternative to colour feature classification using colour contrast ocurrence matrix[END_REF] C 2 O obtain the better score with a gain of 2% on the LBP approach. The second test is processed on the OUTEX extended database, the 12440 images were divided in 50% for train set and 50% for test. We mixed all angles variations.

Illumination spectrum and rotation performance

Using the TC00014 from the OUTEX database, we obtained 1380 sub-images with 3 different lighting therefore 4080 sub-images forming 68 class of 60 samples each. The classification scheme was driven using 50% of the sample for the training and 50% for the classification. [START_REF] Negri | Color texture classification under varying illumination[END_REF]

CONCLUSIONS

In this paper we presented a new way to include the texture and colour informations, based on the Julesz's and Haralick's contributions in the computational sense and on the results of Drimbarean and Palm in colour and texture. The Colour Contrast Occurrence matrix C 2 O is processed in CIEL * a * b * to obtain a correct behavior in front of the human vision and kept the idea of the occurrence but translated into a normalized colour difference.

The results have shown that with the limits induced by the two selected databases, ALOT and OUTEX, the C 2 0 features shows good performance of stability in the recognition of texture under various viewing point or illumination changes. Local Binary Pattern obtains close scores due to a similar construction based on the local difference assessment.

An important aspect of this feature lies in the fact that the C 2 O feature construction produces a dense feature, by opposition to the cooccurrence. As we have shown, the relationship between the color and the texture is directly understandable. At this step, the used feature is a spherical quantization of the three-dimensional clouds. In current works, a modelization is developed to reduce the feature size and improve the classification rate.

Figure 1 .

 1 Figure 1. Impact on C2O of illumination changes (image 110, ALOT database).

Figure 2 .

 2 Figure 2. Viewpoint changes for image 110 ALOT database.

Figure 3 .

 3 Figure 3. Spectra of the illuminant for OUTEX database (from OUTEX website)

Figure 4 .

 4 Figure 4. Variations in the illumination spectrum in the image canvas 2 outex.

Figure 5 .

 5 Figure 5. Variations in the illumination spectrum in the image canvas 20 outex.

Figure 6 .

 6 Figure 6. Viewpoint changes for image canvas 0 OUTEX database.

Table 1

 1 show that other time C 2 O has the best correct classification percentage in front of LBP and the cooccurrence.

		Coocurrence LBP	C 2 O	difference
	alot	48.22	63.72 65.8	2.08%
	outex 70.4	85.3	87.87 2.57%

Table 1 .

 1 Comparison of correct classification score in front of viewpoint modification.

  Table shows that the C 2 O feature obtains the better performance in face of the LBP, the two features presenting larger score than the cooccurrence.

	Coocurrence LBP	C 2 O	difference
	outex 54.01	86.37 85.4	0.9%

Table 2 .

 2 Comparison of correct classification score in front of illumination changes.