HAL Portal usj Université Saint-Joseph de Beyrouth-Liban
Not a member yet
1220 research outputs found
Sort by
Weak trunk extensors in adult spinal deformity patients are related to sagittal malalignment and kinematic limitations
No full textInternational audienceBackground: Adult spinal deformity (ASD) is associated with muscles' degeneration that affects postural control and outcomes of an eventual corrective surgery. Evaluation of ASD is usually based on static radiographs and more recently on functional assessment. However, there has been limited exploration of muscle strength weakness in ASD. The aim was to investigate the relationship between trunk muscles' strength in ASD and its relationship with radiographic and kinematic alterations and quality-of-life decline.Methods: 28 ASD and 18 asymptomatic subjects underwent biplanar radiographs with 3D calculation of spino-pelvic and global postural parameters. 3D movement analysis of gait, sitting to standing and stair ascent, was studied allowing the calculation of head, trunk and lower limbs 3D kinematics. Participants filled out health related quality of life questionnaires. A single operator measured 4 times the strength of the trunk muscles, using a hand-held dynamometer, to assess measurements' reliability. ASD population was divided into two groups based on the strength of trunk extensors: ASD-weak extensors (N = 11 patients having trunk extensors strength0.94). On standing radiographs, the ASD-weak extensors group showed an increased positive sagittal malalignment compared to the other groups (SVA=61 mm vs ASD-normal extensors: 18 mm, controls: -4 mm, p < 0.001). This sagittal malalignment remained during movement (kinematic-SVA=223 mm vs ASD-normal extensors:178 mm, controls:138 mm, p < 0.001). Muscle strength weakness was correlated to the decline of quality-of-life scores (PCS-SF36: r = 0.48, VAS for pain: ρ=-0.39).Conclusions: This study showed that weak trunk extensors are associated with sagittal malalignment in static position, kinematic limitations during daily life activities and reduced quality of life scores. Future studies will investigate the effect of muscle strengthening on both static and dynamic alignment in ASD and their quality of life
Genetic profiling of a hidden grapevine germplasm from the ancient terraces of Hadchit village, North Lebanon
No full textInternational audienceGiven the position of the Lebanese vineyards in the eastern Mediterranean and its long history of viticulture in various agroclimatic conditions, it is likely that this local germplasm holds a large substantial diversity. Nevertheless, it has not been adequately addressed yet. In this study, we shed light on the unnoticed high altitude Lebanese vineyards of Hadchit village (1500 m a.s.l.) in North Lebanon were examined. Based on interviews with local farmers,18 grapevine accessions were selected for the study and information on their traditional and present use, as well as the origin of genetic material was obtained. Genetic analysis was performed with 22 nuclear microsatellite markers widely used in other studies. The average allelic diversity was 6.18 alleles per marker. Genetic profiling yielded 13 different genetic profiles and comparison to international grapevine databases revealed cases of synonymy, duplication, and misnaming, and also showed that nine genetic profiles had no correspondence in these databases. The studied accessions are of interest because of their long history, and diverse modes of utilization. The study highlights the interest of exploring the traditional grapevine germplasm preserved on farm and how it contributes to the genotypic richness held in Lebanon
Chlordecone reduces hyperpolarization-activated-current (Ih) conductance in honeybee
No full textInternational audienceThe pacemaker channel (HCN) is responsible for electrical activity in a wide range of excitable cells, including those of invertebrates. Using Xenopus oocytes and HEK cell, we show here that HCN-channel from Apis mellifera is activated by hyperpolarization, modulated by cAMP, and blocked by cesium. Its PNa/PK relative permeability is 1:3, and its unitary conductance is 1.5 pS, which is similar to that of the mammalian HCN2 channel. Moreover, bee h-current is blocked by high concentrations of ZD7288, and organochlorine pesticide chlordecone reduces Ih amplitude in a dose-dependent manner (IC50 value was 9.37 µM) and diminishes HCN conductance, while preserving voltage dependence. In contrast, Deltamethrin exhibits no discernible impact. Molecular docking of Chlordecone in a homology model of bee HCN generated by AlphaFold3 suggests a binding site located at the end of the S6 helix that could explain the conductance inhibition caused by Chlordecone
Molecularly imprinted electrochemical sensor for fast and direct determination of caffeic acid in wine
No full textInternational audienceCaffeic acid (CA) is widely distributed in the plant kingdom. As an antioxidant, it helps protect food and provides health benefits. Therefore, the determination of this compound in many food and beverage matrices is of particular interest. This study aimed to develop an electrochemical sensor based on a molecularly imprinted polymer (MIP) as a sensitive material for the quantitative determination of caffeic acid in wine. The functional monomer was selected based on molecular simulation. The MIP was polymerized on the surface of a screen-printed carbon electrode (SPCE) using 4-aminobenzoic acid (4-ABA) as a functional monomer and CA as a template. The electropolymerization was performed by cyclic voltammetry (CV) and was optimised to enhance the sensor's selectivity. CA detection by differential pulse voltammetry (DPV) showed a linear response between 0 and 40 μM (R2 = 0.9992), with a limit of detection of 0.68 μM (approximatively 1 mg⋅L−1). The MIP sensor demonstrated selectivity for CA over other interferents, as well as good repeatability and stability. It was successfully applied to wine samples, and its response was compared to that of the HPLC-UV quantification method. Beyond its application in the complex wine matrix, this new MIP-SPCE sensor could also be used to detect CA in various other food matrices
Brewer's spent grain and crude glycerol: Sustainable substrates for 2-phenylethanol production by Yarrowia lipolytica.
No full textInternational audienceThe development of natural, efficient, and cost-effective methods for producing the aromatic alcohol 2-phenylethanol (2-PE) is necessary. 2-PE, characterized by a rosy scent, is widely used in the cosmetic, pharmaceutical, and food industries. It is commonly utilized as a flavoring agent in desserts, baked goods, and beverages, enhancing the overall flavor with fruity, honeyed, creamy, and caramelized notes. In this study, the optimization of 2-PE production through fermentation of the yeast Yarrowia lipolytica on brewer's spent grain (BSG) was examined using a central composite design. The impact of crude glycerol (CG) and yeast extract (YE) on 2-PE production were investigated. A prerequisite for utilizing BSG as a substrate is the hydrolysis of its complex components, primarily starch. This was achieved by transforming the amyloglucosidase (AMG) gene into the genome of Y. lipolytica. Fermentations were carried out in 500 mL baffled Erlenmeyer flasks with a working volume of 100 mL. Optimally, 1.52 g/L of 2-PE was produced after 168 h fermentation in a medium containing 2.87 g/L yeast extract and 45.9 g/L crude glycerol in BSG
Evaluation de la Taille Optimale d'un Micro-réseau Isolé en Fonction de Différentes Stratégies de Gestion de l'Énergie (EMS)
No full textInternational audienc
Unlocking financial peaks: board and audit roles in the GCC
No full textInternational audienceThis research explores the intricate relationship between the board of directors and audit committees, and the subsequent financial performances of companies listed within the Gulf Cooperation Council (GCC). The study unveils a pivotal correlation between the characteristics of a companys board of directors and its financial prosperity. A noteworthy finding is the negative correlation between board size and financial performance, while board independence is positively associated with financial outcomes. Furthermore, the investigation sheds light on a complex interaction between audit committees and boards of directors. Enhanced board independence positively impacts the dimensions of audit committees, whereas an increased board size appears to diminish audit committee autonomy. Additionally, the research emphasises the critical role of audit committee composition in financial performance, revealing that an audit committee with greater autonomy is congruent with enhanced financial results. This study not only contributes to the existing body of knowledge regarding corporate governance and financial performance but also provides practical insights for GCC-listed companies in structuring their boards and audit committees to optimise financial performance
The Evolution of Entrepreneurship Research: A Comprehensive Bibliometric Analysis of IJESB (2004-2024)
No full textInternational audienceThe International Journal of Entrepreneurship and Small Business (IJESB) has grown significantly from 29 articles in 2004 to 78 articles in 2023. During this tenure, the journal has covered a wide range of entrepreneurship aspects including ethnicity, gender bias, and challenges faced by small and medium enterprises (SMEs). As a part of the study bibliometric analysis of 1,508 documents was carried out from 2004 to 2014 from Scopus. Findings show the journal's contributions include wide research from 2,767 authors including 23.67% international collaborations, 4,964 unique keywords, and 70,619 citations. The journal has wide coverage of studies compromising of qualitative as well as quantitative studies indicating a rich knowledgebase in the discipline
AMOEBA Polarizable Molecular Dynamics Simulations of Guanine Quadruplexes: from the c-Kit Proto-oncogene to HIV-1
No full textInternational audienceLong oligomer sequences, rich in guanine and cytosine, such as c-kit1 and the HIV-1 LTR-III sequence, are prevalent in oncogenes and retroviruses and play crucial roles in cancer. Understanding the conformational dynamics of such guanine quadruplexes and identifying druggable regions are therefore essential for developing new inhibition strategies. In this study, we used extensive AMOEBA polarizable force field molecular dynamics simulations combined with data-driven adaptive sampling and clustering algorithms, reaching a cumulative simulation time of 7.5 μs for c-kit1. Such simulations identified novel structural motives and showcased the flexible loop dynamics, as well as the role of polarizable water in transient stabilization of the G-quadruplex. They also identified two druggable pockets in c-kit1. The 400 ns simulation of the HIV-1 LTR-III sequence confirmed its quadruplex stability and uncovered a potentially druggable cryptic pocket
Phase transformation temperatures influence the reduction ratio of fatigue resistance of nickel-titanium reciprocating files at body temperature: an in vitro experimental study
No full textInternational audienceObjectives:The objective of this study was to evaluate the effects of transformational temperatures on the cyclic fatigue resistance at body temperature of reciprocating file systems: R motion (RM), Procodile Q (PQ), and Reciproc Blue. Methods: Resistance test was done in a custom-made device at room (20°C ± 1°C) and body (37°C ± 1°C) temperatures within a 60° angle of curvature and 5 mm radius of the artificial canal. The time to fracture (TTF) was recorded. The scanning electron microscope observation and differential scanning calorimetry analyses were performed. Two-way analysis of variance and Tukey post-hoc comparison were applied at a significance level of 0.05. Results:The results showed a significant influence of temperature on instrumental breakage, regardless of the file systems (p < 0.05). The TTF is significantly decreased at body temperature (p < 0.05). PQ showed the longest TTF in both temperature conditions (p < 0.05). RM demonstrated a significantly higher TTF reduction ratio compared to the other files (p < 0.05). Conclusions: Within the limitations of this study, the heat-treated files with reciprocating kinetics may have different reduction ratios of the fatigue resistance of the file systems under different temperature conditions. This characteristic is an important point of consideration when clinicians select the file system to reduce potential file fracture.</div