Stability control of nonlinear micromechanical resonators under simultaneous primary and superharmonic resonances

Fast effects of a slow excitation on the main resonance of a nonlinear micromechanical resonator are analytically and experimentally investigated. We show, in particular, how the bifurcation topology of an undesirable unstable behavior is modified when the resonator is simultaneously actuated at its primary and superharmonic resonances. A stabilization mechanism is proposed and demonstrated by increasing the superharmonic excitation

Is proton radiation more effective than photon radiation at inducing senescence?

https://openworks.mdanderson.org/sumexp21/1158/thumbnail.jp

Appendagite épiploïque primitive: à propos de cinq cas

La torsion de frange épiploïque (ou appendagite) est une pathologie rare qui survient principalement chez les adultes entre 20 et 50 ans.L'incidence de cette pathologie n'est pas réellement connue et elle varie de 2 à 7% chez les patients hospitalisés pour suspicion d'appendicite oude sigmoïdite. Nous rapportons cinq cas d'appendagites dont nous précisons les particularités cliniques, radiologiques et thérapeutiques. Il s'agit de 5 patients dont l'âge moyen est de 34.6 ans (24-55). Le sexe ratio est de 1.5. Le principal motif de consultation était un syndrome douloureux de l'abdomen principalement au niveau de la fosse iliaque droite. L'examen abdominal montrait toujours une sensibilité localisée. La fièvre était présente chez 3 patients. Le bilan biologique révèle un syndrome inflammatoire biologique chez trois patients. Les examens complémentaires radiologiques en particulier échographie abdominale et TDM abdominale ont éliminé formellement une urgence chirurgicale et ont évoqué le diagnostic d'appendagite dans trois cas. Trois patients ont bénéficié d'une coelioscopie diagnostique confirmant le diagnostic  d'appendagite. L'évolution était favorable chez tous les patients. Les appendagites épiploïques primitives sont des étiologies rares et  sous-estimées de syndrome abdominal aigu. Le diagnostic peut être affirmé par imagerie notamment avec le scanner hélicoïdal injecté,  permettant d'instaurer ainsi un traitement médical premier et d'éviter un traitement chirurgical et des hospitalisations excessives

Conductance statistics from a large array of sub-10 nm molecular junctions

Devices made of few molecules constitute the miniaturization limit that both inorganic and organic-based electronics aspire to reach. However, integration of millions of molecular junctions with less than 100 molecules each has been a long technological challenge requiring well controlled nanometric electrodes. Here we report molecular junctions fabricated on a large array of sub-10 nm single crystal Au nanodots electrodes, a new approach that allows us to measure the conductance of up to a million of junctions in a single conducting Atomic Force Microscope (C-AFM) image. We observe two peaks of conductance for alkylthiol molecules. Tunneling decay constant (beta) for alkanethiols, is in the same range as previous studies. Energy position of molecular orbitals, obtained by transient voltage spectroscopy, varies from peak to peak, in correlation with conductance values.Comment: ACS Nano (in press

Prevalence of Mood Disorders and Associated Factors at the Time of the COVID-19 Pandemic: Potocol for a Community Survey in La Manouba Governorate, Tunisia

Aims: The present survey aims to assess the overall mood disorder prevalence and identify associated socio-demographic and clinical factors in a Tunisian community sample, with special attention to the COVID-19 pandemic. Background: Mood disorders are one of the leading causes of all non-fatal burdens of disease, with depression being at the top of the list. The COVID-19 pandemic may have increased the prevalence of mood disorders, especially in Low and Middle-income countries (LMICs) and in vulnerable populations. Objective: 1/ Assess point and lifetime prevalence of depressive and bipolar disorders as well as subthreshold bipolarity in a representative population sample of La Manouba governorate and assess treatment patterns for these disorders; 2/Study socio-demographic and clinical correlates of mood disorders 3/ Assess the association between mood disorders and quality of life 4/ Study the impact of the COVID-pandemic on the prevalence of mood disorders 5/ Assess coping mechanisms to the COVID-pandemic and whether these mechanisms moderate the appearance of mood disorders or symptoms since the beginning of the pandemic Methods: This is a household cross-sectional observational survey to be conducted in La Manouba Governorate in a sample of 4540 randomly selected individuals aged ≥ 15 years. Data collection will be carried out by trained interviewers with clinical experience, through face-to-face interviews and the use of the computer assisted personal interviewing approach (CAPI). The following assessment tools are administered: Results: Structured clinical Interview for DSM IV-TR (Mood disorder section and Screening questions on Anxiety), Mood Disorder Questionnaire (MDQ), Suicide Behaviors Questionnaire-Revised (SBQ), 12-item Short Form Survey (SF-12), the Brief-COPE, and a questionnaire about a headache. In addition, socio-demographic and clinical data will be collected. Conclusion: This will be one of the very few household surveys in a general population sample to assess mental health problems and COVID-19-related variables since the beginning of the pandemic. Through this research, we aim to obtain an epidemiological profile of mood disorders in Tunisia and an estimation of the impact of the COVID-19 pandemic on their prevalence. Results should contribute to improving mental health care in Tunisia

Acute left ventricular dysfunction secondary to right ventricular septal pacing in a woman with initial preserved contractility: a case report

<p>Abstract</p> <p>Introduction</p> <p>Right ventricular apical pacing-related heart failure is reported in some patients after long-term pacing. The exact mechanism is not yet clear but may be related to left ventricular dyssynchrony induced by right ventricular apical pacing. Right ventricular septal pacing is thought to deteriorate left ventricular function less frequently because of a more normal left ventricular activation pattern.</p> <p>Case presentation</p> <p>We report the case of a 55-year-old Tunisian woman with preserved ventricular function, implanted with a dual-chamber pacemaker for complete atrioventricular block. Right ventricular septal pacing induced a major ventricular dyssynchrony, severe left ventricular ejection fraction deterioration and symptoms of congestive heart failure. Upgrading to a biventricular device was associated with a decrease in the symptoms and the ventricular dyssynchrony, and an increase of left ventricular ejection fraction.</p> <p>Conclusion</p> <p>Right ventricular septal pacing can induce reversible left ventricular dysfunction and heart failure secondary to left ventricular dyssynchrony. This complication remains an unpredictable complication of right ventricular septal pacing.</p

Formability analysis of pre-strained AA5754-O sheet metal using Yld96 plasticity theory: Role of amount and direction of uni-axial pre-strain

Automotive industries are very much interested in formability of different pre-strained aluminum alloy sheets in the context of multistage stamping to fabricate complex components. In the present work, different uni-axial pre-strains of 6.4% and 12.2% were induced in AA5754-O aluminum alloy both along rolling direction (RD) and transverse direction (TD). The true stress-strain response, limiting dome height (LDH) and strain based forming limit diagram (ε-FLD) of as received and all pre-strained materials were evaluated experimentally. The anisotropy constitutive material model was developed using the Yld96 plasticity theory in-conjunction with the Hollomon isotropic hardening law to predict the yield strength evolution of the pre-strained materials. Also, it was found that the limiting strains in ε-FLD shifted significantly depending on the amount and direction of uni-axial pre-strain. Hence, the limiting strains of the as-received materials were transposed into stress space to estimate the stress based forming limit diagram (σ-FLD) using the anisotropy constitutive material model. Further, the dynamic shifts of ε-FLDs of four different pre-strained materials were predicted by successfully decoupling the σ-FLD of as-received materials within root mean square error of 0.008. Finite element models of both uni-axial pre-straining and subsequent LDH tests were developed, and the forming behavior of the pre-strained materials were predicted implementing the Yld96 plasticity model and estimated σ-FLD. It was found that LDH was significantly influenced by the amount of pre-strain, and the maximum thinning location shifted close to pole in the case of 12.2% pre-strained materials. However, the effect of uni-axial pre-strain direction on both LDH and maximum thinning location in AA5754-O material was very negligible

Contribution of type 2 diabetes associated loci in the Arabic population from Tunisia: a case-control study

<p>Abstract</p> <p>Background</p> <p>Candidate gene and genome-wide association studies have both reproducibly identified several common Single Nucleotide Polymorphisms (SNPs) that confer type 2 diabetes (T2D) risk in European populations. Our aim was to evaluate the contribution to T2D of five of these established T2D-associated loci in the Arabic population from Tunisia.</p> <p>Methods</p> <p>A case-control design comprising 884 type 2 diabetic patients and 513 control subjects living in the East-Center of Tunisia was used to analyze the contribution to T2D of the following SNPs: E23K in <it>KCNJ11/Kir6.2</it>, K121Q in <it>ENPP1</it>, the -30G/A variant in the pancreatic β-cell specific promoter of Glucokinase, rs7903146 in <it>TCF7L2 </it>encoding transcription factor 7-like2, and rs7923837 in <it>HHEX </it>encoding the homeobox, hematopoietically expressed transcription factor.</p> <p>Results</p> <p><it>TCF7L2</it>-rs7903146 T allele increased susceptibility to T2D (OR = 1.25 [1.06–1.47], <it>P </it>= 0.006) in our study population. This risk was 56% higher among subjects carrying the TT genotype in comparison to those carrying the CC genotype (OR = 1.56 [1.13–2.16], <it>P </it>= 0.002). No allelic or genotypic association with T2D was detected for the other studied polymorphisms.</p> <p>Conclusion</p> <p>In the Tunisian population, <it>TCF7L2</it>-rs7903146 T allele confers an increased risk of developing T2D as previously reported in the European population and many other ethnic groups. In contrast, none of the other tested SNPs that influence T2D risk in the European population was associated with T2D in the Tunisian Arabic population. An insufficient power to detect minor allelic contributions or genetic heterogeneity of T2D between different ethnic groups can explain these findings.</p

Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation

<p>Abstract</p> <p>Background</p> <p>Thymoquinone is an active principle of <it>Nigella sativa </it>seed known as "Habbah Al-Sauda" in Arabic countries and "Sinouj" in Tunisia. Bacterial biofilms tend to exhibit significant tolerance to antimicrobials drugs during infections.</p> <p>Methods</p> <p>The antibacterial activity of Thymoquinone (TQ) and its biofilm inhibition potencies were investigated on 11 human pathogenic bacteria. The growth and development of the biofilm were assessed using the crystal violet (CV) and the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay.</p> <p>Results</p> <p>TQ exhibited a significant bactericidal activity against the majority of the tested bacteria (MICs values ranged from 8 to 32 μg/ml) especially Gram positive cocci (<it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510). Crystal violet assay demonstrated that the minimum biofilm inhibition concentration (BIC50) was reached with 22 and 60 μg/ml for <it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510 respectively. In addition our data revealed that cells oxidative activity was influenced by TQ supplementation. In the same way, TQ prevented cell adhesion to glass slides surface.</p> <p>Conclusion</p> <p>The ability of TQ to prevent biofilm formation warrants further investigation to explore its use as bioactive substances with antibiofilm potential.</p

Assessing the performance of a serological point-of-care test in measuring detectable antibodies against SARS-CoV-2

This study investigated the performance of a rapid point-of-care antibody test, the BioMedomics COVID-19 IgM/IgG Rapid Test, in comparison with a high-quality, validated, laboratory-based platform, the Roche Elecsys Anti-SARS-CoV-2 assay. Serological testing was conducted on 709 individuals. Concordance metrics were estimated. Logistic regression was used to assess associations with seropositivity. SARS-CoV-2 seroprevalence was 63.5% (450/709; 95% CI 59.8%-67.0%) using the BioMedomics assay and 71.9% (510/709; 95% CI 68.5%-75.2%) using the Elecsys assay. There were 60 discordant results between the two assays, all of which were seropositive in the Elecsys assay, but seronegative in the BioMedomics assay. Overall, positive, and negative percent agreements between the two assays were 91.5% (95% CI 89.2%-93.5%), 88.2% (95% CI 85.1%-90.9%), and 100% (95% CI 98.2%-100%), respectively, with a Cohen’s kappa of 0.81 (95% CI 0.78–0.84). Excluding specimens with lower (Elecsys) antibody titers, the agreement improved with overall, positive, and negative percent concordance of 94.4% (95% CI 92.3%-96.1%), 91.8% (95% CI 88.8%-94.3%), and 100% (95% CI 98.2%-100%), respectively, and a Cohen’s kappa of 0.88 (95% CI 0.85–0.90). Logistic regression confirmed better agreement with higher antibody titers. The BioMedomics COVID-19 IgM/IgG Rapid Test demonstrated good performance in measuring detectable antibodies against SARS-CoV-2, supporting the utility of such rapid point-of-care serological testing to guide the public health responses and vaccine prioritization. © 2022 Coyle et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited