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Search Results: 1 - 10 of 223799 matches for " R. Sellem "
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Characterization of a detector chain using a FPGA-based Time-to-Digital Converter to reconstruct the three-dimensional coordinates of single particles at high flux
F. Nogrette,D. Heurteau,R. Chang,Q. Bouton,C. I. Westbrook,R. Sellem,D. Clément
Physics , 2015, DOI: 10.1063/1.4935474
Abstract: We report on the development of a novel FPGA-based Time-to-Digital Converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of Micro-Channel Plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1x10^6 per second and three-dimensional reconstruction of the coordinates up to 3.2x10^6 particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) um. In addition we analyze a method to measure the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work directly apply to the detection of other kinds of particles.
G$^0$ Electronics and Data Acquisition (Forward-Angle Measurements)
D. Marchand,J. Arvieux,L. Bimbot,A. Biselli,J. Bouvier,H. Breuer,R. Clark,J. -C. Cuzon,M. Engrand,R. Foglio,C. Furget,X. Grave,B. Guillon,H. Guler,P. M. King,S. Kox,J. Kuhn,Y. Ky,J. Lachniet,J. Lenoble,E. Liatard,J. Liu,E. Munoz,J. Pouxe,G. Quéméner,B. Quinn,J. -S. Réal,O. Rossetto,R. Sellem
Physics , 2007, DOI: 10.1016/j.nima.2007.11.028
Abstract: The G$^0$ parity-violation experiment at Jefferson Lab (Newport News, VA) is designed to determine the contribution of strange/anti-strange quark pairs to the intrinsic properties of the proton. In the forward-angle part of the experiment, the asymmetry in the cross section was measured for $\vec{e}p$ elastic scattering by counting the recoil protons corresponding to the two beam-helicity states. Due to the high accuracy required on the asymmetry, the G$^0$ experiment was based on a custom experimental setup with its own associated electronics and data acquisition (DAQ) system. Highly specialized time-encoding electronics provided time-of-flight spectra for each detector for each helicity state. More conventional electronics was used for monitoring (mainly FastBus). The time-encoding electronics and the DAQ system have been designed to handle events at a mean rate of 2 MHz per detector with low deadtime and to minimize helicity-correlated systematic errors. In this paper, we outline the general architecture and the main features of the electronics and the DAQ system dedicated to G$^0$ forward-angle measurements.
Predictors of additional intraocular pressure reduction in patients changed to latanoprost/timolol fixed combination
Eric Sellem, Jean Rouland, Christophe Baudouin, Alain Bron, Philippe Denis, Jean-Philippe Nordmann, Jean Renard
BMC Ophthalmology , 2010, DOI: 10.1186/1471-2415-10-10
Abstract: This multicenter, open-label, prospective, phase IIIb study included subjects ≥18 years of age with open-angle glaucoma (OAG) or ocular hypertension (OHT). Eligible subjects had baseline IOP ≥21 mmHg and insufficient response to current beta-blocker monotherapy. The primary efficacy analysis (logistic regression) identified predictors of a positive response after 12 weeks of latanoprost/timolol FC.The intent-to-treat (ITT) population included 383 subjects treated with ≥1 drop of FC and having ≥1 follow-up IOP assessment. Mean IOP was 22.19 ± 2.16 mmHg at baseline and was reduced by 5.42 ± 2.71 mmHg at study end. In all, 325 (84.9%) subjects had a positive response to latanoprost/timolol FC; the response rate was similar across groups: OAG (n = 208; 82.7%); OHT (n = 161; 87.6%); OAG+OHT (n = 14; 85.7%). Higher baseline IOP (odds ratio: 1.284; 95% confidence interval [CI]: 1.101, 1.497; p = 0.0014) and absence of adverse events (odds ratio: 0.318; 95% CI: 0.161, 0.629; p = 0.0010) were significant predictors of positive response. Age, gender, ethnic origin, diagnosis, family history of OAG/OHT, corneal thickness, and concomitant systemic beta-blocker were not significant predictors of a positive response in the ITT analysis. The FC was well tolerated. The most common adverse events were related to the eye and were consistent with known adverse events associated with latanoprost and timolol.These results support the use of latanoprost/timolol FC in patients whose IOP is insufficiently controlled on beta-blocker monotherapy. Patients with higher baseline IOP levels and who do not experience adverse events while on therapy are most likely to achieve a positive response to latanoprost/timolol FC.Study registration number: NCT00230763Disease progression in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT) can be slowed or stopped by reducing intraocular pressure (IOP) levels though the use of ocular hypotensive agents [1-5]. First-choice options for medi
Desmoplastic small round cell tumor: impact of 18F-FDG PET induced treatment strategy in a patient with long-term outcome
Dorra Ben-Sellem,Kun-Lun Liu,Sébastien Cimarelli,André Constantinesco
Rare Tumors , 2009, DOI: 10.4081/rt.2009.e19
Abstract: The desmoplastic small round cell tumor (DSRCT) is an uncommon and highly aggressive cancer. The role of 18F-FDG PET in management of DSRCT is little reported. We report a case of metastasized abdominal DSRCT detected in a 43-year old patient whose diagnostic and therapeutic approaches were influenced by 18F-FDG PET-CT. The patient is still alive ten years after diagnosis. 18F-FDG PET-CT seems to be a useful method for assessing therapeutic efficiency and detecting early recurrences even in rare malignancies such as DSRCT.
First-line latanoprost therapy in ocular hypertension or open-angle glaucoma patients: a 3-month efficacy analysis stratified by initial intraocular pressure
Philippe Denis, Christophe Baudouin, Alain Bron, Jean-Philippe Nordmann, Jean Renard, Jean Rouland, Eric Sellem, Mourad Amrane
BMC Ophthalmology , 2010, DOI: 10.1186/1471-2415-10-4
Abstract: This prospective, open-label, multicenter, uncontrolled, phase IV study included treatment-naive ocular hypertension or open-angle glaucoma subjects initiating latanoprost once daily (evening). IOP levels were measured at baseline and after 1 and 3 months. The primary efficacy outcome was mean change in IOP from baseline to month 3. Analyses were stratified by baseline IOP: ≥ 20 and <24 mmHg vs ≥ 24 mmHg.Efficacy analyses (intent to treat) included 572 subjects: 20 to <24 mmHg group, N = 252; ≥ 24 mmHg group, N = 320. Mean baseline IOP levels were 22.2 ± 0.9 mmHg and 26.7 ± 2.8 mmHg, respectively. At month 3, significant IOP reductions were seen in both groups (p < 0.0001, within-group differences); reductions were smaller in the 20 to <24 mmHg group (-6.3 ± 2.4 vs -9.2 ± 3.7 mmHg, respectively; -28.0 ± 10.6% vs -34.1 ± 11.9%, respectively). An IOP reduction of ≥ 30% from baseline to month 3 was noted in 48.4% and 65.6% of subjects, respectively (p < 0.0001). At month 3, targets IOPs of ≤ 18 mmHg were achieved by ≥ 70% of subjects in both groups. Latanoprost was well tolerated with an adverse event profile similar to that reported in the literature.This "real world" study found once-daily latanoprost to be effective and safe in treatment-naive ocular hypertension or open-angle glaucoma patients. Patients with baseline IOP levels of 20 to <24 mmHg as well as ≥ 24 mmHg benefitted from initial latanoprost therapy.Trial Registration Number: NCT00647101Glaucoma is among the leading causes of blindness worldwide [1], and elevated intraocular pressure (IOP) is a major risk factor for progression of both ocular hypertension and glaucoma [2]. Reducing IOP prevents or delays the onset of open-angle glaucoma in patients with ocular hypertension [3] and slows progression among those with open-angle glaucoma [4-8].Treatment to reduce IOP levels commonly begins with topical ocular hypotensive agents. Among these, latanoprost, which became available in 1996 and was approved by the
Metabolomic Characterization of Ovarian Epithelial Carcinomas by HRMAS-NMR Spectroscopy
D. Ben Sellem,K. Elbayed,A. Neuville,F.-M. Moussallieh,G. Lang-Averous,M. Piotto,J.-P. Bellocq,I. J. Namer
Journal of Oncology , 2011, DOI: 10.1155/2011/174019
Abstract: Objectives. The objectives of the present study are to determine if a metabolomic study by HRMAS-NMR can (i) discriminate between different histological types of epithelial ovarian carcinomas and healthy ovarian tissue, (ii) generate statistical models capable of classifying borderline tumors and (iii) establish a potential relationship with patient's survival or response to chemotherapy. Methods. 36 human epithelial ovarian tumor biopsies and 3 healthy ovarian tissues were studied using 1H HRMAS NMR spectroscopy and multivariate statistical analysis. Results. The results presented in this study demonstrate that the three histological types of epithelial ovarian carcinomas present an effective metabolic pattern difference. Furthermore, a metabolic signature specific of serous (N-acetyl-aspartate) and mucinous (N-acetyl-lysine) carcinomas was found. The statistical models generated in this study are able to predict borderline tumors characterized by an intermediate metabolic pattern similar to the normal ovarian tissue. Finally and importantly, the statistical model of serous carcinomas provided good predictions of both patient's survival rates and the patient's response to chemotherapy. Conclusions. Despite the small number of samples used in this study, the results indicate that metabolomic analysis of intact tissues by HRMAS-NMR is a promising technique which might be applicable to the therapeutic management of patients. 1. Introduction Epithelial ovarian carcinoma is one of the most frequent malignancies of the female genital tract and represents the leading cause of death among women with gynecologic cancer. The overall 5-year survival still remains at about 44% [1]. Clinicians face two key problems: late diagnosis at advanced stages which is more difficult to treat and resistance to treatment of the majority of recurrences. Thus, there is a need for improved imaging methods to predict treatment response and detect tumor recurrence not invasively [2, 3]. The unfavorable statistics in ovarian cancer patients reflect, in part, a poor understanding of the molecular pathogenesis of this heterogeneous malignancy [4]. Several studies have been performed for the metabolic characterization of ovarian carcinomas using ex vivo?1H nuclear magnetic resonance (NMR) spectroscopy in tumor tissues [5, 6], cyst fluid [7–9], or cell lines [10] and by in vivo?1H MR spectroscopy [9, 11–14]. So far, no studies have yet been performed using 1H high-resolution magic angle spinning (HRMAS) NMR spectroscopy. This technique affords a detailed and accurate analysis of the
Biological Roles of the Podospora anserina Mitochondrial Lon Protease and the Importance of Its N-Domain
Céline Adam, Marguerite Picard, Michelle Déquard-Chablat, Carole H. Sellem, Sylvie Hermann-Le Denmat, Véronique Contamine
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038138
Abstract: Mitochondria have their own ATP-dependent proteases that maintain the functional state of the organelle. All multicellular eukaryotes, including filamentous fungi, possess the same set of mitochondrial proteases, unlike in unicellular yeasts, where ClpXP, one of the two matricial proteases, is absent. Despite the presence of ClpXP in the filamentous fungus Podospora anserina, deletion of the gene encoding the other matricial protease, PaLon1, leads to lethality at high and low temperatures, indicating that PaLON1 plays a main role in protein quality control. Under normal physiological conditions, the PaLon1 deletion is viable but decreases life span. PaLon1 deletion also leads to defects in two steps during development, ascospore germination and sexual reproduction, which suggests that PaLON1 ensures important regulatory functions during fungal development. Mitochondrial Lon proteases are composed of a central ATPase domain flanked by a large non-catalytic N-domain and a C-terminal protease domain. We found that three mutations in the N-domain of PaLON1 affected fungal life cycle, PaLON1 protein expression and mitochondrial proteolytic activity, which reveals the functional importance of the N-domain of the mitochondrial Lon protease. All PaLon1 mutations affected the C-terminal part of the N-domain. Considering that the C-terminal part is predicted to have an α helical arrangement in which the number, length and position of the helices are conserved with the solved structure of its bacterial homologs, we propose that this all-helical structure participates in Lon substrate interaction.
Experimental Relocation of the Mitochondrial ATP9 Gene to the Nucleus Reveals Forces Underlying Mitochondrial Genome Evolution
Ma?lis Bietenhader equal contributor,Alexandre Martos equal contributor,Emmanuel Tetaud equal contributor,Raeka S. Aiyar equal contributor,Carole H. Sellem,Roza Kucharczyk,Sandra Clauder-Münster,Marie-France Giraud,Fran?ois Godard,Bénédicte Salin,Isabelle Sagot,Julien Gagneur,Michelle Déquard-Chablat,Véronique Contamine,Sylvie Hermann-Le Denmat,Annie Sainsard-Chanet,Lars M. Steinmetz ,Jean-Paul di Rago
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002876
Abstract: Only a few genes remain in the mitochondrial genome retained by every eukaryotic organism that carry out essential functions and are implicated in severe diseases. Experimentally relocating these few genes to the nucleus therefore has both therapeutic and evolutionary implications. Numerous unproductive attempts have been made to do so, with a total of only 5 successes across all organisms. We have taken a novel approach to relocating mitochondrial genes that utilizes naturally nuclear versions from other organisms. We demonstrate this approach on subunit 9/c of ATP synthase, successfully relocating this gene for the first time in any organism by expressing the ATP9 genes from Podospora anserina in Saccharomyces cerevisiae. This study substantiates the role of protein structure in mitochondrial gene transfer: expression of chimeric constructs reveals that the P. anserina proteins can be correctly imported into mitochondria due to reduced hydrophobicity of the first transmembrane segment. Nuclear expression of ATP9, while permitting almost fully functional oxidative phosphorylation, perturbs many cellular properties, including cellular morphology, and activates the heat shock response. Altogether, our study establishes a novel strategy for allotopic expression of mitochondrial genes, demonstrates the complex adaptations required to relocate ATP9, and indicates a reason that this gene was only transferred to the nucleus during the evolution of multicellular organisms.
The genome sequence of the model ascomycete fungus Podospora anserina
Eric Espagne, Olivier Lespinet, Fabienne Malagnac, Corinne Da Silva, Olivier Jaillon, Betina M Porcel, Arnaud Couloux, Jean-Marc Aury, Béatrice Ségurens, Julie Poulain, Véronique Anthouard, Sandrine Grossetete, Hamid Khalili, Evelyne Coppin, Michelle Déquard-Chablat, Marguerite Picard, Véronique Contamine, Sylvie Arnaise, Anne Bourdais, Véronique Berteaux-Lecellier, Daniel Gautheret, Ronald P de Vries, Evy Battaglia, Pedro M Coutinho, Etienne GJ Danchin, Bernard Henrissat, Riyad EL Khoury, Annie Sainsard-Chanet, Antoine Boivin, Bérangère Pinan-Lucarré, Carole H Sellem, Robert Debuchy, Patrick Wincker, Jean Weissenbach, Philippe Silar
Genome Biology , 2008, DOI: 10.1186/gb-2008-9-5-r77
Abstract: We present a 10X draft sequence of P. anserina genome, linked to the sequences of a large expressed sequence tag collection. Similar to higher eukaryotes, the P. anserina transcription/splicing machinery generates numerous non-conventional transcripts. Comparison of the P. anserina genome and orthologous gene set with the one of its close relatives, Neurospora crassa, shows that synteny is poorly conserved, the main result of evolution being gene shuffling in the same chromosome. The P. anserina genome contains fewer repeated sequences and has evolved new genes by duplication since its separation from N. crassa, despite the presence of the repeat induced point mutation mechanism that mutates duplicated sequences. We also provide evidence that frequent gene loss took place in the lineages leading to P. anserina and N. crassa. P. anserina contains a large and highly specialized set of genes involved in utilization of natural carbon sources commonly found in its natural biotope. It includes genes potentially involved in lignin degradation and efficient cellulose breakdown.The features of the P. anserina genome indicate a highly dynamic evolution since the divergence of P. anserina and N. crassa, leading to the ability of the former to use specific complex carbon sources that match its needs in its natural biotope.With one billion years of evolution [1], probably more than one million species [2] and a biomass that may exceed that of animals [3,4], eumycete fungi form one of the most successful groups of eukaryotes. Not surprisingly, they have developed numerous adaptations allowing them to cope with highly diverse environmental conditions. Presently, virtually all biotopes, with the exception of extreme biotopes (that is, hyperthermophilic areas), contain some representative eumycetes. They feed by osmotrophy and import through very efficient transporters the nutrients they take up from the environment, often by degrading complex material, such as plant cell walls, tha
Power Aware Routing Protocol (PARP) for Wireless Sensor Networks  [PDF]
R. Prema, R. Rangarajan
Wireless Sensor Network (WSN) , 2012, DOI: 10.4236/wsn.2012.45019
Abstract: Several wireless sensor network applications ought to decide the intrinsic variance between energy efficient communication and the requirement to attain preferred quality of service (QoS) such as packet delivery ratio, delay and to reduce the power consumption of wireless sensor nodes. In order to address this challenge, we propose the Power Aware Routing Protocol (PARP), which attains application-specified communication delays at low energy cost by dynamically adapting transmission power and routing decisions. Extensive simulation results prove that the proposed PARP attains better QoS and reduced power consumption.
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