HAL Portal usj Université Saint-Joseph de Beyrouth-Liban
Not a member yet
1220 research outputs found
Sort by
A Geant4-DNA Evaluation of Radiation-Induced DNA Damage on a Human Fibroblast
No full textInternational audienceAccurately modeling the radiobiological mechanisms responsible for the induction of DNA damage remains a major scientific challenge, particularly for understanding the effects of low doses of ionizing radiation on living beings, such as the induction of carcinogenesis. A computational approach based on the Monte Carlo technique to simulate track structures in a biological medium is currently the most reliable method for calculating the early effects induced by ionizing radiation on DNA, the primary cellular target of such effects. The Geant4-DNA Monte Carlo toolkit can simulate not only the physical, but also the physico-chemical and chemical stages of water radiolysis. These stages can be combined with simplified geometric models of biological targets, such as DNA, to assess direct and indirect early DNA damage. In this study, DNA damage induced in a human fibroblast cell was evaluated using Geant4-DNA as a function of incident particle type (gammas, protons, and alphas) and energy. The resulting double-strand break yields as a function of linear energy transfer closely reproduced recent experimental data. Other quantities, such as fragment length distribution, scavengeable damage fraction, and time evolution of damage within an analytical repair model also supported the plausibility of predicting DNA damage using Geant4-DNA.The complete simulation chain application “molecularDNA”, an example for users of Geant4-DNA, will soon be distributed through Geant4
Identification of genetically diverse landscapes for conservation and use of plant, animal, and forest genetic resources
No full textInternational audienc
Performance of Narrowband IoT Link Adaptation with Rate and Energy Objectives
No full textInternational audienceThis paper provides a detailed investigation on the performance of Narrowband IoT link adaptation under different approaches: Max-Rate approach, Min-Energy approach and the Max-Energy-Efficiency approach while considering realistic channel estimation. Simulation results study the impact of the received power on the performance of the link adaptation in terms of the achieved consumed energy, data rate, energy efficiency, and spectral efficiency. Particularly, we show that maximizing data rate in NB-IoT leads to maximizing the spectral efficiency except at extremely low received powers. Also, results focus on the impact of the data size on the performance of the link adaptation in NB-IoT. We show that larger data sizes lead to higher energy consumption, lower data rate and lower energy efficiency.</div
Mechanical Cell Disruption Technologies for the Extraction of Dyes and Pigments from Microorganisms: A Review
No full textInternational audienceThe production of pigments using single cell microorganisms is gaining traction as a sustainable alternative to conventional syntheses, which rely, in no negligible proportions, on petrochemicals. In addition to depending on petroleum, these syntheses involved the use of toxic organic solvents, which may be inadequately disposed of across a range of industries, thus compounding the deleterious effects of fossil fuel exploitation. Literature suggests that notable research efforts in the area of sustainable pigment production using single cell microorganisms are focused on the production of pigments coveted for their interesting qualities, which transcend their mere capacity to dye various fabrics both natural and synthetic. As interest in sustainable pigment biosynthesis grows, the need to devise effective and efficient cell disruption processes becomes more pressing given that the viability of pigment biosynthesis is not only dependent on microorganisms’ yield in terms of production, but also on researchers’ ability to recover them. This review chiefly reports findings as to mechanical cell disruption methods, used individually or in various combinations, and their aptitude to recover biosynthetic pigments
EBT3 Gafchromic® film as a new substrate for in vitro evaluation of sun protection factor
No full textInternational audienceBackgroundThere exist different methods for the determination of sun protection factor (SPF) values for sunscreens.ObjectivesWe aimed to develop a new in vitro method using EBT3 Gafchromic® film as a substrate.Materials & MethodsThe colour of EBT3 Gafchromic® film changes when exposed to UV light. Films were covered by sunscreen preparations of different SPF values ranging from 0 to 50. Uncovered and covered films were exposed to different solar light energies and their colour change was compared. Absorbance spectra of films was measured at 633 nm using a UV-VIS spectrophotometer apparatus.ResultsThe colour of the film darkens when ultraviolet energy increases, which means that absorbance increases with exposure time. However, when films are covered by sunscreens, the colour change is less visible and the absorbance significantly decreases with increasing SPF value.ConclusionThere is a linear correlation between the absorbance of EBT3 Gafchromic® film and SPF value of sunscreens covering the film. Statistical analysis demonstrated that the SPF value of a sunscreen can be predicted using EBT3 Gafchromic® film as a substrate. This is the first report of an in vitro method based on colour change of a substrate which takes into consideration exposure time, and relates more closely to conditions of real-life. Based on these parameters, this is a reliable in vitro method for SPF testing
Fluoroless endourological surgery for high burden renal and proximal ureteric stones: A safe technique for experienced surgeons
No full textInternational audienceObjective: To describe the feasibility of treating proximal ureteric and renal stones using flexible ureteroscopy (fURS) or a double approach (mini-percutaneous nephrolithotomy [PCNL] + fURS) without any use of radiation. Patients and methods: We retrospectively reviewed the data of all patients operated by one surgeon for retrograde endoscopic removal of renal and ureteric lithiasis performed between June 2015 and January 2019 in our institution. Patients with anatomical complexities, highburden stone disease (diameter >20 mm), and medical comorbidities (anti-platelet drug administration) were included in our study. Outcomes analysed included complication rate, stone-free rate (SFR, defined as no residual stone >1 mm), and repeat procedure rate. Results: In all, 183 consecutive URS for proximal ureteric and renal lithiasis were conducted. C-arm fluoroscope guidance was not required, not even in the complex cases. Simultaneous ultrasonography and fURS guidance was used in patients where the mini-PCNL approach was indicated. Lead aprons were not needed by the operating room staff in any of the operations. The SFR was 91.8% after the first procedure, with no Clavien-Dindo Grade III or IV complications. Conclusion: Our present series shows clearly that the fURS and mini-PCNL approach under fURS control is a feasible and safe technique for experienced surgeons. Patients had a high SFR and no technique-related complications, with no additional risk of X-ray exposure. However, a prospective study is required to test the reproducibility of this technique
Change tolerance, group focus and students' entrepreneurial intentions: does gender matter?
No full textInternational audiencePurpose This study examines the impact of cultural dimensions on entrepreneurial intentions (EIs) and the mediating role of planned behavior (TPB) determinants between change tolerance (CT), group focus (GF), and EIs for both men and women in the context of international business schools. Design/methodology/approach Using a quantitative research design, data were collected in France through anonymous questionnaires. The data consisted of responses from 480 business students. Structural equation modeling (SEM) and the bootstrap method with PROCESS macro were used to determine the significance of the mediation effects. Findings Results reveal the strong impact of CT on the EIs of both men and women through TPB antecedents. They also indicate that GF has an indirect effect on EIs through TPB antecedents for men and an indirect multiple mediation effect on EIs through CT and TPB antecedents for both men and women. Originality/value The extended TPB model is original in that it supports both the determinants of planned behavior and cultural dimensions and provides a valuable perspective through its findings on cultural and gender diversity in entrepreneurship
Occurence of the mobile colistin resistance gene mcr-1 in extended-βlactamase-and pAmpC-β-lactamase-producing Escherichia coli from broilers in Lebanon
No full textsession : Bacterial susceptibility and resistancesous-session : Resistance surveillance and epidemiology: Gram-negativesInternational audienc
Quantitative analysis of lower limb and pelvic deformities in children with X-linked hypophosphatemic rickets
No full textInternational audienceIntroductionX-linked hypophosphatemia (XLH) rickets mainly causes leg deformities in children that can get worse as they grow. We hypothesized that quantifying the bone parameters will help to document and monitor these deformities in children with XLH.MethodsThirty-five growing children affected by XLH were included in this cross-sectional study. Biplanar radiographs were taken with an EOS system allowing 3D reconstructions of the pelvis and legs. Sixteen geometric parameters were calculated for the legs and pelvis. A control group of 40 age-matched patients was used to define the reference values for these geometric parameters.Results For the legs, significant differences (p < 0.05) appeared between the XLH patients and the control group in the neck-shaft angle, femur/tibia length ratio and HKS. Among the 70 legs in the XLH group, 23 were in genu varum, 25 were in genu valgum and 22 were straight. There were significant differences between the genu varum and genu valgum subgroups in the femoral mechanical angle and the HKS. A strong correlation was found between the femoral mechanical angle and tibiofemoral angle (r² = 0.73) and between the femoral mechanical angle and HKS (r²=0.69) The sacral slope and acetabular anteversion were significant different from the reference values. DiscussionQuantitative radiological parameters derived from 3D reconstructions show that the deformities in XLH patients are 1) mainly in but not limited to the femoral shaft; 2) highly variable from one person to another. Some of these radiological parameters may be useful for the diagnosis and monitoring of XLH patients
Negative symptoms in schizophrenia: correlation with clinical and genetic factors
No full textInternational audienceAim: Explore the possible association between clinical factors and genetic variants of the dopamine pathways and negative symptoms. Materials & methods: Negative symptoms were assessed in 206 patients with schizophrenia using the Arabic version of the self-evaluation of negative symptoms scale and the Positive and Negative Syndrome Scale. Genotyping for COMT, DRD2, MTHFR and OPRM1 genes was performed. Results: Multivariable analysis showed that higher self-evaluation of negative symptoms scale scores were significantly associated with higher age, higher chlorpromazine-equivalent daily dose for typical antipsychotics and in married patients. Higher negative Positive and Negative Syndrome Scale scores were significantly associated with women and having the CT genotype for MTHFR c.677C>T (β = 4.25; p = 0.008) compared with CC patients. Conclusion: Understanding both clinical/genetic factors could help improve the treatment of patients