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On the electrical conductivity of alginate hydrogels

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Regenerative Biomaterials 2018年第5期5卷 293-301页

作者： Georgia Kaklamani Diana Kazaryan James Bowen fabrice Iacovella Spiros H.Anastasiadis George Deligeorgis Institute of Electronic Structure&Laser Foundation for Research&Technology HellasP.O.Box 138571110 HeraklionCreteGreece School of Engineering and Innovation The Open UniversityMilton Keynes MK76AAUK Department of Chemistry University of CreteP.O.Box 220871003 HeraklionCreteGreece

Hydrogels have been extensively used in the field of biomedical applications,offering customizable natural,synthetic or hybrid materials,particularly relevant in the field of tissue *** the bioelectronics discipline,hydrogels are promising mainly as sensing platforms with or without encapsulated cells,showing great potential in healthcare and ***,to date there is little data in the literature which characterizes the electrical properties of tissue engineering materials which are relevant to *** this work,we present electrical characterization of alginate hydrogels,a natural polysaccharide,using a four-probe method similar to electrical impedance *** acquired conductance data show distinct frequency-dependent features that change as a function of alginate and crosslinker concentration reflecting ion kinetics inside the measured ***,the presence of NIH 3T3 fibroblasts encapsulated in the hydrogels matrix was found to alter the artificial tissue’s electrical *** method used provides valuable insight to the frequency-dependent electrical response of the resulting *** is hoped that the outcome of this research will be of use in the development of cell/electronic interfaces,possibly toward diagnostic biosensors and therapeutic bioelectronics.

关键词： alginate bioelectronics conductivity hydrogel polysaccharide resistance fibroblasts

Functional Accumulation of Antenna Proteins in Chlorophyll b-Less Mutants of Chlamydomonas reinhardtii

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Molecular Plant 2017年第1期10卷 115-130页

作者： Sandrine Bujaldon Natsumi Kodama fabrice Rappaport Rajagopal Subramanyam Catherine de Vitry Yuichiro Takahashi FrancisAndre Wollman Institut de Biologie Physico-Chimique UMR7141 CNRS-UPMC Paris 75005 France Research Institute for Interdisciplinary Science Okayama University Okayama 700-8530 Japan JST-CREST Okayama University Okayama 700-8530 Japan Department of Plant Sciences School of Life Sciences University of Hyderabad Hyderabad 500046 India These authors contributed equally to this article Deceased while manuscript was in progress

The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes （LHC）- four major LHCIIs, two minor LHClIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to assess the effect of chlorophyll b deficiency on the function, assembly, and stability of these chlorophyll a/b binding proteins. We identified point mutations in two mutants that inactivate the CAO gene responsible for chlorophyll a to chlorophyll b conversion. All LHClIs accumulated to wild-type levels in a CAO mutant but their light-harvesting function for photosystem II was impaired. In contrast, most LHCIs accumulated to wild-type levels in the mutant and their light-harvesting capability for photosystem I remained unaltered. Unexpectedly, LHCl accumulation and the photosystem I functional antenna size increased in the mutant compared with in the wild type when grown in dim light. When the CAO mutation was placed in a yellow-in-the-dark background （yid-BF3）, in which chlorophyll a synthesis remains limited in dim light, accumulation of the major LHClIs and of most LHCls was markedly reduced, indicating that sustained synthesis of chlorophyll a is required to preserve the proteolytic resistance of antenna pro- teins. Indeed, after crossing yid-BF3 with a mutant defective for the thylakoid FtsH protease activity, yid- BF3-ftshl restored wild-type levels of LHCI, which defines LHCI as a new substrate for the FtsH protease.

关键词： Chlamydomonas reinhardtii chlorophyll b-less mutant antenna protein CAO gene

Nonlinear gallium phosphide nanoscale photonics[Invited]

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Photonics Research 2018年第5期6卷 I0068-I0074页

作者： AUDE MARTIN SYLVAIN COMBRIE ALFREDO DE ROSSI GREGOIRE BEAUDOIN ISABELLE SAGNES fabrice RAINERI Centre de Nanosciences et de Nanotechnologies CNRSUniversite Paris-SudUniversite Pans-SaclayC2N Marcoussis91460 MarcoussisFrance Thales Research and Technology France 1 avenue Augustin Fresnel91120 PalaiseauFrance Universite Paris Diderot Sorbone Paris Cite75013 ParisFrance

We introduce a nanoscale photonic platform based on gallium phosphide. Owing to the favorable material properties, peak power intensity levels of 50 GW∕cm^2 are safely reached in a suspended membrane. Consequently,the field enhancement is exploited to a far greater extent to achieve efficient and strong light–matter *** an example, parametric interactions are shown to reach a deeply nonlinear regime, revealing cascaded fourwave mixing leading to comb generation and high-order soliton dynamics.

关键词： Invited Nonlinear gallium phosphide nanoscale photonics

Oleic Acid (OA), A Potential Dual Contrast Agent for Postmortem MR Angiography (PMMRA): A Pilot Study

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Current Medical Science 2020年第4期40卷 786-794页

作者： Zhi-yuan XIA Christine BRUGUIER fabrice DEDOUIT Silke GRABHERR Marc AUGSBURGER Bei-bei LIU Institute of Evidence Law and Forensic Science China University of Political Science and Law(CUPL)Key Laboratory of Evidence Law and Forensic ScienceMinistry of EducationBeijing 100088China University Center of Legal Medicine Lausanne-Geneva(CURML)Lausanne CH1000Switzerland Service de Mede cine Legale Hopital de RangueilToulouse 50032France Dian Research Center for Postmortem Imaging&Angiography Beijing 100192China

Summary:Choosing proper perfusates as contrast agents is an important aspect for postmortem magnetic resonance angiography(PMMRA).However,in this emerging field,the number of suitable kinds of liquid is still very *** objective of this research is to compare MR images of oleic acid(OA)with paraffin oil(PO)in vitro and in ex situ animal hearts,in order to evaluate the feasibility to use OA as a novel contrast agent for *** vitro,OA,PO and water(control)were introduced into three tubes separately and T,weighted-spin echo(Tw SE)and T2w-SE images were acquired on a 1.5T MR *** the second experiment,0A and PO were injected into left coronary artery(LCA)and left ventricle(LV)of ex situ bovine hearts and their Tw-SE,Tzw-SE,Tw-multipoint Dixon(Tjw-mDixon)and 3DT2w-mDixon images were *** overall results indicate that OA may have a potential to be used as a dual(T and T2 based)contrast agent for PMMRA when proper sequence parameters are ***,as the pilot study was based on limited number of animal hearts,more researches using OA in cadavers are needed to validate our findings.

关键词： postmortem magnetic resonance angiography perfusate contrast agent oleic acid paraffin oil heart

PETO Interacts with Other Effectors of Cyclic Electron Flow in Chlamydomonas

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Molecular Plant 2016年第4期9卷 558-568页

作者： Hiroko Takahashi Stefan Schmollinger Jae-Hyeok Lee Michael Schroda fabrice Rappaport Francis-Andre Wollman Olivier Vallon Institut de Biologie Physice-Chimique UMR 7141 CNRS-UPMC 13 rue Pet M Curie Paris 75005 France Molecular Biotechnology and Systems Biology University of Kaiserslautem Kaiserlautem 67663 Germany Department of Botany University of British Columbia Vancouver BC V6T1Z4 Canada Present address: Graduate School of Science and Engineering Saitama University 255 Shimo-Okubo Sakura-ku Saitama 33808570 Japan present address: Department of Chemistry and Biochemistry University of California Los Angeles CA 90095 USA

While photosynthetic linear electron flow produces both ATP and NADPH, cyclic electron flow （CEF） around photosystem I （PSI） and cytochrome bef generates only ATP. CEF is thus essential to balance the supply of ATP and NADPH for carbon fixation; however, it remains unclear how the system tunes the relative levels of linear and cyclic flow. Here, we show that PETO, a transmembrane thylakoid phosphoprotein specific of green algae, contributes to the stimulation of CEF when cells are placed in anoxia. In oxic conditions, PETO co-fractionates with other thylakoid proteins involved in CEF （ANR1, PGRL1, FNR）. In PETO-knock- down strains, interactions between these CEF proteins are affected. Anoxia triggers a reorganization of the membrane, so that a subpopulation of PSi and cytochrome bsf now co-fractionates with the CEF effectors in sucrose gradients. The absence of PETO impairs this reorganization. Affinity purification identifies ANR1 as a major interactant of PETO. ANR1 contains two ANR domains, which are also found in the N-terminal region of NdhS, the ferredoxin-binding subunit of the plant ferredoxin-plastoquinone oxidoreductase （NDH）. We propose that the ANR domain was co-opted by two unrelated CEF systems （PGR and NDH）, possibly as a sensor of the redox state of the membrane.

关键词： time-resolved spectroscopy chlorophyll fluorescence tridecyl-maltoside sucrose gradient ultracen-trifugation state transition STT7

Is Fish Domestication Going Too Fast?

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Natural Resources 2016年第6期7卷 399-404页

作者： fabrice Teletchea Research Unit Animal and Functionalities of Animal Products (URAFPA) University of Lorraine Nancy France

Domestication is a very strong process that has enabled humans to produce both plants and animals with desired traits. For land animals, this process started about 12,000 years ago and resulted in that today hundreds of well-defined breeds are available for the five most important farmed mammal species (cattle, pig, horse, sheep and goat). For aquatic animals, this process started much earlier, and the bulk of domestication of new species dated back only to the early 1980s. Nevertheless, there are now numerous fish species for which the life cycle is already closed in captivity and some domesticated fish have been genetically improved. This implies that what probably took hundreds of years in mammals (i.e., to control the life cycle in captivity and then to improve captive individuals) has been accomplished in only tens of years for some fish species. Based on the main problems observed today in farmed mammals, the possible consequences of this fast domestication of fish are discussed.

关键词： Domestication Farmed Animals Mammals Fish Global Change

How Perceived Benefits and Barriers Affect Millennial Professionals’ Online Security Behaviors

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Journal of Information Security 2019年第4期10卷 278-301页

作者： fabrice Djatsa Research and Development Department Caelid Technology Triangle USA

Over the past decade, there has been an increase in cybersecurity breaches through identity theft, hacking, phishing attacks, and the use of malware such as viruses, worms, or trojans. The breaches have triggered an increase in investment in information security in organizations. As technology continues to improve, the risks of having cybersecurity incidents also increase. Cybersecurity firms reported that in 2016, there were 1209 total breaches with 1.1 billion identities exposed. Most experts agree that human vulnerability is a significant factor in cybersecurity. Most issues related to advanced threats come from human nature and ignorance. For the study, the researcher examined the relationship between Millennial professionals’ perceptions of cybersecurity risks and users’ online security behaviors. The study focused on two elements of perception which are perceived benefits and perceived barriers. The researcher administered a survey to 109 participants randomly selected among Survey Monkey audience members. The Spearman’s correlation test performed supported the analysis of the strength of the relationship and the level of significance between each of the independent variables and the dependent variable. The results from the statistical test provided enough evidence to reject each of the null hypothesis tested in this study. There were significant correlations between each of the independent variables, Perceived Benefits (PBE) and Perceived Barriers (PBA) and the dependent variable Online Security Behaviors (OSB).

关键词： Perceptions Barriers Benefits Online Security Behaviors Millennial

Helicobacter pylori Infection and Gastroduodenal Lesions: Prevalence and Associated Factors in Cote d’Ivoire

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Open Journal of Gastroenterology 2022年第2期12卷 27-35页

作者： Mamadou Diakité Amadou Koné Akoun fabrice Aké Kouassi Olivier Claver Koffi Anassi Jean Baptiste Okon Kadidiatou Diallo Department of Medicine and Hepato-Gastroenterology Teaching Hospital of Bouaké Bouaké Cote d’Ivoire Faculty of Medical Sciences Alassane Ouattara University Bouaké Cote d’Ivoire

Objective: The objective is to determine the prevalence of Helicobacter pylori (Hp) infection and highlight the determinants of the infection as well as the gastric histopathological lesions associated with this infection. Methods: This is a retrospective study carried out from August 01, 2015 to December 31, 2020 in Bouaké. It included all patients with gastric and/or duodenal lesion on upper gastrointestinal endoscopy in whom gastric biopsies and histopathology results are available. Results: The study involved 510 patients (301 men and 209 women). The prevalence of Hp was 66.47% (339/510 patients). The presence of Hp was not significantly related to age and gender. Epigastralgia was the most common indication with no significant difference between the positive and negative Hp groups (65.37% vs 34.63%, p = 0.35). A significant difference was only observed for duodenal ulcers (84.31% Hp+ vs 15.69% Hp-, p = 0.004). Regarding histological lesions: Chronic and active gastritis was strongly related to the presence of Hp (p < 0.05). Intestinal metaplasia and gastric atrophy were not significantly associated with the presence of Hp. These precursor lesions of gastric cancer (metaplasia and atrophy) were, however, significantly related to chronic gastric disease with p = 0.02 and p Conclusion: The prevalence of Hp is high in Bouaké. Our study confirms the link between Hp infection and chronic and active gastritis.

关键词： Helicobacter Pylori Gastritis Atrophy Intestinal Metaplasia

Threat Perceptions, Avoidance Motivation and Security Behaviors Correlations

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Journal of Information Security 2020年第1期11卷 19-45页

作者： fabrice Djatsa Research and Development Department Caelid Technology Triangle USA

As the economy increases its dependence on the internet to increase efficiency and productivity in all aspects of society, close attention has been directed to solve the challenges related to internet security. Despite the large amount of resource invested so far in this area, cybersecurity challenges are still great as the media frequently report new cyber breaches. Although researchers acknowledge that great progress has been made in protecting digital assets, cybercriminals are still successful in their operations which are no longer limited to government entities and corporations but also individual computer users. To improve users’ security posture, the researcher examined the relationship between Millennials’ perceptions of cybersecurity threat, users’ online security behaviors and avoidance motivation. The study focused on three constructs which are Perceived Threat (PTH), Online Security Behaviors (OSB) and Avoidance Motivation (AMO). The researcher administered a survey to 109 participants randomly selected in the United States. The Spearman’s correlation test performed supported the analysis of the strength of the relationship and the level of significance between the independent variable and the dependent variables. The results from the statistical test provided enough evidence to fail to reject the null hypothesis related to relationships between PTH and OSB and to reject the null hypothesis regarding the relationship between PTH and AMO.

关键词： Millennial Perceptions Threat Avoidance Motivation Online Security Behaviors