Barbell back squat:How do resistance bands affect muscle activation and knee kinematics?

ObjectivesThis study aimed to determine whether looped resistance bands affect knee kinematics and lower body muscle activation during the barbell back squat.MethodsTwenty-six healthy participants (13 female, 13 male) calculated their one repetition maximum (RM) prior to data collection. Each participant performed three squats at both 80% and 40% 1RM wearing a light resistance band, an extra-heavy resistance band and no resistance band.Vicon 3D motion analysis cameras were used to collect the kinematic data, and Delsys Trigno Lab wireless electromyography (EMG) system was used to measure vastus medialis, vastus lateralis, gluteus maximus, gluteus medius and biceps femoris muscle activity. Peak knee flexion angle, peak knee valgus angle and maximum tibial rotation values were examined. Peak EMG values were also analysed after being normalised and expressed as a percentage of maximum voluntary contraction (MVC).ResultsGluteus maximus (GM) activity is significantly increased when a resistance band is used during squatting. However, squatting with a resistance band is detrimental to knee kinematics as it leads to an increase in knee valgus angle and maximum tibial rotation angle. A direct correlation is recorded between an increase in resistance and an increase in these two angles.ConclusionsSquatting with resistance bands is likely to increase the risk of knee injury. Coaches and clinicians who already implement this technique are advised to remove resistance band squats from training and rehabilitation programmes. Further research evaluating the long-term effects of using resistance bands during the barbell back squat should be considered

A retrospective study of antibiotic resistance patterns of bacterial pathogens isolated from patients in two Lebanese hospitals for two consecutive years (2018 and 2019)

Background: Misuse of antibiotics is the leading factor promoting emergence of bacterial resistance, a situation that has become a serious public health challenge. Among the leading bacteria that have developed resistance to antibiotics are Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, which have caused infections in patients, resulting in considerable mortality. The objective of this retrospective study was to assess antibiotic resistance rates of bacterial pathogens isolated from clinical specimens in two Lebanese hospitals between the years 2018 and 2019. Methodology: Bacteria isolated from routine clinical specimens collected from hospitalized patients in two hospitals, Haroun and Bekaa, in Lebanon for 2018 and 2019, were analyzed. Bacteria isolation and identification were carried out at the laboratory of each hospital using conventional microbiological methods. Antimicrobial susceptibility testings (AST) of each bacterial isolate to antibiotics were performed by the disc diffusion test and interpreted using EUCAST, CLSI or WHO/AST guidelines. Comparisons of the mean resistance rates of each isolate to individual antibiotics by year of isolation were done using the Z-test and p< 0.05 was considered statistically significant. Results: There were a total of 1698 bacteria isolates recovered from hospitalized patients in the two hospitals for 2018 and 2019, of which 87.5% were Gram-negative and 12.5% were Gram-positive bacteria. The most frequent among the Gram-negative isolates was E. coli (66.1%) followed by P. aeruginosa (13.3%), K. pneumoniae (7.7%), Proteus mirabilis (6.7%) and Enterobacter spp (6.3%), while coagulase positive staphylococci CoPS (68.4%) and E. faecalis (31.6%) were the two Gram positive isolates. Of the Gram-negative isolates over the two-year period, 72.2% of E. coli and 76.3% of K. pneumoniae were resistant to ceftazidime, 93% of P. mirabilis to colistin, and 98% of Enterobacter to cefoxitin, but low resistance rates were demonstrated by E. coli to imipenem (1%), K. pneumoniae to tigecycline and amikacin (0.9%), P. mirabilis to imipinem (2%), and Enterobacter to amikacin, ertapenem and tigecycline (3%). Resistance of P. aeruginosa varied between 2% to colistin and 24% to levofloxacin. For the Gram-positive bacteria, 79.1% of E. faecalis were resistant to erythromycin while 70% of CoPS were resistant to cefoxitin, but no isolate was resistant (0%) to linezolid, and only 1% to teicoplanin. Except for Enterobacter spp that showed significant increase in resistance rates (by 250%) to piperacillin/tazobactam in 2019 over 2018, resistance rates of other Gram-negative isolates significantly decreased in 2019 compared to 2018 (p<0.05). For the Gram-positive isolates, resistance rates to many antibiotics tested significantly increased (by a factor of 36.5 - 2569%) in 2019 compared to 2018 among E. faecalis isolates in contrast to the rates for CoPS which significantly decreased by 16.7 - 65.7%, except for penicillin G which increased by a factor of 123%. Conclusion: Overuse and misuse of antibiotics, which is possible because of the easy access of the populace to these drugs, is a leading factor contributing to the high antibiotic resistance rates in this study. There is need to promote awareness of antimicrobial resistance in Lebanon among students especially in non-health related majors and enactment of govermental policy that will limit access to antibiotics. Keywords: antibiotic resistance; changing pattern; hospitalized patients; retrospective   French title: Une étude rétrospective des profils de résistance aux antibiotiques de pathogènes bactériens isolés de patients dans deux hôpitaux libanais pendant deux années consécutives (2018 et 2019) Contexte: La mauvaise utilisation des antibiotiques est le principal facteur favorisant l'émergence de la résistance bactérienne, une situation qui est devenue un sérieux défi de santé publique. Parmi les principales bactéries qui ont développé une résistance aux antibiotiques figurent Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae et Pseudomonas aeruginosa, qui ont provoqué des infections chez les patients, entraînant une mortalité considérable. L'objectif de cette étude rétrospective est d'évaluer les taux de résistance aux antibiotiques des pathogènes bactériens isolés à partir d'échantillons cliniques dans deux hôpitaux Libanais entre les années 2018 et 2019. Méthodologie: Les isolats bactériens prélevés sur des patients hospitalisés dans deux hôpitaux, Haroun et Bekaa, au Liban pour 2018 et 2019, ont été analysés. L'isolement et l'identification des bactéries ont été réalisés au laboratoire de chaque hôpital en utilisant des méthodes microbiologiques conventionnelles. Les tests de sensibilité aux antimicrobiens (AST) de chaque isolat bactérien aux antibiotiques ont été réalisés par le test de diffusion sur disque et interprétés selon les directives EUCAST, CLSI ou WHO/AST. Des comparaisons des taux moyens de résistance de chaque isolat à des antibiotiques individuels par année d'isolement ont été effectuées à l'aide du test Z et p<0,05 a été considéré comme statistiquement significatif. Résultats: Il y a eu un total de 1698 isolats de bactéries récupérés de patients hospitalisés dans les deux hôpitaux durant 2018 et 2019, dont 87,5% étaient à Gram négatif et 12,5% étaient des bactéries à Gram positif. Les isolats à Gram négatif les plus fréquents étaient E. coli (66,1%), suivis de P. aeruginosa (13,3%), K. pneumoniae (7,7%), Proteus mirabilis (6,7%) et Enterobacter spp (6,3%), tandis que les staphylocoques à coagulase positive CoPS (68,4%) et E. faecalis (31,6%) étaient les deux isolats Gram positifs. Parmi les isolats à Gram négatif sur la période de deux ans, 72,2% d'E. coli et 76,3% de K. pneumoniae étaient résistants à la ceftazidime, 93% de P. mirabilis à la colistine et 98% d'Enterobacter à la céfoxitine, mais faible les taux de résistance ont été démontrés par E. coli à l'imipénem (1%), K. pneumoniae à la tigécycline et à l'amikacine (0,9%), P. mirabilis à l'imipinem (2%) et Enterobacter à l'amikacine, à l'ertapénem et à la tigécycline (3%). La résistance de P. aeruginosa variait entre 2% à la colistine et 24% à la lévofloxacine. Pour les bactéries Gram positif, 79,1% des E. faecalis étaient résistantes à l'érythromycine tandis que 70% des CoPS étaient résistantes au céfoxitin, mais aucun isolat n'était résistant (0%) au linézolide et seulement 1% à la teicoplanine. À l'exception d'Enterobacter spp qui ont montré une augmentation significative des taux de résistance (de 250%) à la  pipéracilline/tazobactam en 2019 par rapport à 2018, les taux de résistance des autres isolats à Gram négatif ont considérablement  diminué en 2019 par rapport à 2018 (p<0,05). Pour les isolats Gram-positifs, les taux de résistance à de nombreux antibiotiques testés ont augmenté de manière significative (d'un facteur de 36,5 à 2569%) en 2019 par rapport à 2018 parmi les isolats d'E. faecalis contrairement aux taux de CoPS qui ont significativement diminué de 16,7 à 65,7%, à l'exception de la pénicilline G qui a augmenté d'un facteur de 123%. Conclusion: la surutilisation et la mauvaise utilisation des antibiotiques, ce qui est possible en raison de l'accès facile de la population à ces médicaments, est l'un des principaux facteurs contribuant aux taux élevés de résistance aux antibiotiques dans cette étude. Il est nécessaire de promouvoir la sensibilisation à la résistance aux antimicrobiens au Liban parmi les étudiants, en particulier dans les spécialisations non liées à la santé, et la promulgation d'une politique gouvernementale qui limitera l'accès non contrôlé aux antibiotiques. Mots clés: résistance aux antibiotiques; changement de modèle; patients hospitalisés; rétrospectiv

System multilayered applied to the radiative cooling

In applied optics, the multilayered structures (MLS) take an important place in many instrumental and industrial devices. The aim of this work is to study the MLS in order to optimize the inverse greenhouse effect; it is made by a survey on theoretical formalism of the energy exchange phenomena. This optimization requires that the window materials (MLS) are good reflectors in the visible range and assuring a total transmission in the infrared zone (8-13 µm); One of the support elements, of the window, answering to these criterions is germanium, for which we have studied the thickness influence and have found that the equilibrium temperature reached by the absorber has a minimal value between 0.01 µm and 0.06 µm. However, only with germanium, the window can not products the inverse greenhouse effect. Indeed, the germanium must include other layers in order to increase the visible reflectance and the infrared transmittance (8-13µm); what forms a multilayered structure. Several system have been used, only 7 of them have been kept for this work: S1, S2, …, S7 systems. Only the following systems: S2/S1, S3/S2/S1 and MgO/S3/S2/S1 give a radiative cooling effect, with a very good result of 15 °C below ambient temperature in the case of the S6 system. To approach of the real conditions of this system realization (S6), we simulated the effects of such imperfections, as presence of air, that would be due to the quality of the layers deposition. This study is made in the case of the S7 system. As results, we found that, for zenithal angles ≤ 60°, the layers of air, for which the thickness is lower than 0.5 µm, don't present any influence on the absorber's equilibrium temperature.In applied optics, the multilayered structures (MLS) take an important place in many instrumental and industrial devices. The aim of this work is to study the MLS in order to optimize the inverse greenhouse effect; it is made by a survey on theoretical formalism of the energy exchange phenomena. This optimization requires that the window materials (MLS) are good reflectors in the visible range and assuring a total transmission in the infrared zone (8-13 µm); One of the support elements, of the window, answering to these criterions is germanium, for which we have studied the thickness influence and have found that the equilibrium temperature reached by the absorber has a minimal value between 0.01 µm and 0.06 µm. However, only with germanium, the window can not products the inverse greenhouse effect. Indeed, the germanium must include other layers in order to increase the visible reflectance and the infrared transmittance (8-13µm); what forms a multilayered structure. Several system have been used, only 7 of them have been kept for this work: S1, S2, …, S7 systems. Only the following systems: S2/S1, S3/S2/S1 and MgO/S3/S2/S1 give a radiative cooling effect, with a very good result of 15 °C below ambient temperature in the case of the S6 system. To approach of the real conditions of this system realization (S6), we simulated the effects of such imperfections, as presence of air, that would be due to the quality of the layers deposition. This study is made in the case of the S7 system. As results, we found that, for zenithal angles ≤ 60°, the layers of air, for which the thickness is lower than 0.5 µm, don't present any influence on the absorber's equilibrium temperature

Simulations of Ductile Fracture in an Idealized Ship Grounding Scenario Using Phenomenological Damage and Cohesive Zone Models

Two complementary simulation methodologies for ductile fracture in large sheet metal components are presented and evaluated in this paper. The first approach is based on the phenomenological dilatational plasticity-damage model developed by Woelke and Abboud [68], which accounts for pressure-dependent volumetric damage growth through a scalar damage variable. The damage function represents phenomenologically micromechanical changes the material undergoes during the process of necking. Secondly, the cohesive zone model with an opening mode traction-separation law is employed to simulate the same ductile fracture problems accounting for significant variation of the multiaxial stress state along the crack path. Both methods are examined as to their capabilities to reproduce and predict the outcome of large scale experimental fracture tests of welded and unwelded ductile plates subjected to large-scale penetration, simulating an idealized ship grounding (Alsos and Amdahl, [1, 2]). The results of the current study indicate that, with appropriate calibration, both approaches can be successfully employed to simulate ductile fracture in structural components under multiaxial stress. The advantages and shortcomings of each approach is discussed from the point of view of post-test numerical investigation as well as its predictive capabilities as an engineering tool.Engineering and Applied Science

Extraneural metastases from cranial meningioma: a case report

Extracranial metastases from brain meningiomas is a rare, but well-documented entity. Metastases occur mostly in the lungs, pleura and liver, but may also affect lymph nodes and bones. We report here on a patient who was treated for an atypical brain meningioma with multiple surgeries and multiple sessions of stereotactic radiosurgery with good control of his brain disease. Thirteen years after diagnosis, he developed bilateral large sacroiliac and abdominal metastases

Computational evidence for an early, amplified systemic inflammation program in polytrauma patients with severe extremity injuries

Extremity and soft tissue injuries contribute significantly to inflammation and adverse in-hospital outcomes for trauma survivors; accordingly, we examined the complex association between clinical outcomes inflammatory responses in this setting using in silico tools. Two stringently propensity-matched, moderately/severely injured (Injury Severity Score > 16) patient sub-cohorts of ~30 patients each were derived retrospectively from a cohort of 472 blunt trauma survivors and segregated based on their degree of extremity injury severity (above or below 3 on the Abbreviated Injury Scale). Serial blood samples were analyzed for 31 plasma inflammatory mediators. In addition to standard statistical analyses, Dynamic Network Analysis (DyNA) and Principal Component Analysis (PCA) were used to model systemic inflammation following trauma. Patients in the severe extremity injury sub-cohort experienced longer intensive care unit length of stay (LOS), total LOS, and days on a mechanical ventilator, with higher Marshall Multiple Organ Dysfunction (MOD) Scores over the first 7 days post-injury as compared to the mild/moderate extremity injury sub-cohort. The higher severity cohort had statistically significant elevated lactate, base deficit, and creatine phosphokinase on first blood draw, along with significant changes in multiple circulating inflammatory mediators. DyNA pointed to a sustained role for type 17 immunity in both sub-cohorts, along with IFN-γ in the severe extremity injury group. DyNA network complexity increased over 7 days post-injury in the severe injury group, while generally decreasing over this same time period in the mild/moderate injury group. PCA suggested a more robust activation of multiple pathways in the severe extremity injury group as compared to the mild/moderate injury group. These studies thus point to the possibility of self-sustaining inflammation following severe extremity injury vs. resolving inflammation following less severe extremity injury

Glenoid Dysplasia: Radiographic, Direct MR Arthrographic and Arthroscopic Appearances

AbstractGlenoid dysplasia is an uncommon developmental abnormality of the scapula that is frequently overlooked. We report a case of severe glenoid dysplasia in a 55 year old man and demonstrate its radiographic, direct MR arthrographic and arthroscopic appearances

Trunk proprioception adaptations to creep deformation

PURPOSE: This study aimed at identifying the short-term effect of creep deformation on the trunk repositioning sense. METHODS: Twenty healthy participants performed two different trunk-repositioning tasks (20° and 30° trunk extension) before and after a prolonged static full trunk flexion of 20 min in order to induce spinal tissue creep. Trunk repositioning error variables, trunk movement time and erector spinae muscle activity were computed and compared between the pre- and post-creep conditions. RESULTS: During the pre-creep condition, significant increases in trunk repositioning errors, as well as trunk movement time, were observed in 30° trunk extension in comparison to 20°. During the post-creep condition, trunk repositioning errors variables were significantly increased only when performing a 20° trunk extension. Erector spinae muscle activity increased in the post-creep condition, while it remained unchanged between trunk repositioning tasks. CONCLUSIONS: Trunk repositioning sense seems to be altered in the presence of creep deformation, especially in a small range of motion. Reduction of proprioception acuity may increase the risk of spinal instability, which is closely related to the risk of low back pain or injury

Novel control of lactate dehydrogenase from the freeze tolerant wood frog: Role of posttranslational modifications

Lactate dehydrogenase (LDH), the terminal enzyme of anaerobic glycolysis, plays a crucial role both in sustaining glycolytic ATP production under oxygen-limiting conditions and in facilitating the catabolism of accumulated lactate when stress conditions are relieved. In this study, the effects on LDH of in vivo freezing and dehydration stresses (both of which impose hypoxia/anoxia stress on tissues) were examined in skeletal muscle of the freeze-tolerant wood frog, Rana sylvatica. LDH from muscle of control, frozen and dehydrated wood frogs was purified to homogeneity in a two-step process. The kinetic properties and stability of purified LDH were analyzed, revealing no significant differences in Vmax, Km and I50 values between control and frozen LDH. However, control and dehydrated LDH differed significantly in Km values for pyruvate, lactate, and NAD, I50 urea, and in temperature, glucose, and urea effects on these parameters. The possibility that posttranslational modification of LDH was responsible for the stable differences in enzyme behavior between control and dehydrated states was assessed using ProQ diamond staining to detect phosphorylation and immunoblotting to detect acetylation, methylation, ubiquitination, SUMOylation and nitrosylation of the enzyme. LDH from muscle of dehydrated wood frogs showed significantly lower levels of acetylation, providing one of the first demonstrations of a potential role for protein acetylation in the stress-responsive control of a metabolic enzyme