41 research outputs found

    Inelastic Neutron scattering in CeSi_{2-x}Ga_x ferromagnetic Kondo lattice compounds

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    Inelastic neutron scattering investigation on ferromagnetic Kondo lattice compounds belonging to CeSi_{2-x}Ga_{x}, x = 0.7, 1.0 and 1.3, system is reported. The thermal evolution of the quasielastic response shows that the Kondo interactions dominate over the RKKY interactions with increase in Ga concentration from 0.7 to 1.3. This is related to the increase in k-f hybridization with increasing Ga concentration. The high energy response indicates the ground state to be split by crystal field in all three compounds. Using the experimental results we have calculated the crystal field parameters in all three compounds studied here.Comment: 12 Pages Revtex, 2 eps figures

    Assessment of brain injury biomechanics in soccer heading using finite element analysis

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    This study presents an in silico finite element (FE) model-based biomechanical analysis of brain injury metrics and associated risks of a soccer ball impact to the head for aware and unaware athletes, considering ball impact velocity and direction. The analysis presented herein implements a validated soccer ball and 50th percentile human head computational FE model for quantifying traumatic brain injury (TBI) metrics. The brain's mechanical properties are designated using a viscoelastic-viscoplastic constitutive material model for the white and gray matter within the human head FE model. FE results show a dynamic human head-soccer ball peak contact area of approximately seven times greater than those documented for helmet-to-helmet hits in American Football. Due to the deformable nature of the soccer ball, the impact dynamics are unique depending on the location and velocity of impact. TBI injury risks also depend on the location of impact and the impact velocity. Impacts to the rear (BrIC:0.48, HIC15:180.7), side (BrIC:0.52, HIC15:176.5), and front (BrIC:0.37, HIC15:129.0) are associated with the highest injury risks. Furthermore, the FE results indicate when an athlete is aware of an incoming ball, HIC15-based Abbreviated Injury Scale 1 (AIS 1) injury risks for the front, side, and rear impacts decrease from 10.5%, 18.5%, and 19.3%, respectively, to approximately 1% in front and side impacts and under 6% in a rear impact. Lastly, the unique contact area between the head and soccer ball produces pressure gradients in the ball that translate into distinguishable stress waves in the skull and the cerebral cortex

    Sequence Analysis of Novel Staphylococcus aureus Lineages from Wild and Captive Macaques

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    Staphylococcus aureus is a widespread and common opportunistic bacterium that can colonise or infect humans as well as a wide range of animals. There are a few studies of both methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolated from monkeys, apes, and lemurs, indicating a presence of a number of poorly or unknown lineages of the pathogen. In order to obtain insight into staphylococcal diversity, we sequenced strains from wild and captive individuals of three macaque species (Macaca mulatta, M. assamensis, and M. sylvanus) using Nanopore and Illumina technologies. These strains were previously identified by microarray as poorly or unknown strains. Isolates of novel lineages ST4168, ST7687, ST7688, ST7689, ST7690, ST7691, ST7692, ST7693, ST7694, ST7695, ST7745, ST7746, ST7747, ST7748, ST7749, ST7750, ST7751, ST7752, ST7753, and ST7754 were sequenced and characterised for the first time. In addition, isolates belonging to ST2990, a lineage also observed in humans, and ST3268, a MRSA strain already known from macaques, were also included into the study. Mobile genetic elements, genomic islands, and carriage of prophages were analysed. There was no evidence for novel host-specific virulence factors. However, a conspicuously high rate of carriage of a pathogenicity island harbouring edinB and etD2/etE as well as a higher number of repeat units within the gene sasG (encoding an adhesion factor) than in human isolates were observed. None of the strains harboured the genes encoding Panton–Valentine leukocidin. In conclusion, wildlife including macaques may harbour an unappreciated diversity of S. aureus lineages that may be of clinical relevance for humans, livestock, or for wildlife conservation, given the declining state of many wildlife populations

    Sequential herbicide application coupled with mulch enhances the productivity and quality of winter onion (Allium cepa L.) while effectively controlling the mixed weed flora

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    Weed control poses substantial difficulties for winter season onion (Allium cepa L.) cultivation in the north-western Indo-Gangetic Plains, primarily due to the constrained efficacy of the existing herbicides. To address this issue, a 2-year field study was conducted to assess the efficacy of pre- and post-emergence herbicides (pendimethalin, ethoxysulfuron, imazethapyr, and quizalofop-p-ethyl) individually and in combination with crop residue mulch for weed control in winter onion. The results revealed that using herbicides or mulches in isolation did not provide satisfactory weed control. However, the integration of natural mulch with pendimethalin followed by quizalofop-p-ethyl application proved to be the most effective weed control strategy, resulting in the least reduction in bulb yield (10.3%) compared to other treatments. On the contrary, combinations of pendimethalin with ethoxysulfuron or imazethapyr showed adverse effects on the onion crop and inflicted the highest yield losses among all treatments (78.6 and 83.4%, respectively). However, the combination of pendimethalin with quizalofop-p-ethyl coupled with crop mulch resulted in season-long weed control and over 80% bulb yield (36.58 t/ha) gains compared to the weed-free condition. These findings emphasize the efficacy of combining herbicides and mulches as an integrated weed management strategy for onions. By adopting such integrated approaches, farmers could improve weed control while maintaining bulb yield and quality, reducing the risks associated with herbicide resistance, and promoting sustainable onion production in the north-western Indo-Gangetic Plains

    Weed dynamics, wheat (Triticum aestivum) yield and irrigation water-use efficiency under conservation agriculture

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    A field experiment was conducted to evaluate the impacts of a 12-year old conservation agriculture (CA)- based pigeon pea-wheat system on weeds, wheat crop, and resource use during winter (rabi) 2021–22. Results indicated that surface retention of residue irrespective of ZT permanent bed and N dose led to significant reduction in weed interference at 60 DAS. CA-based systems reduced weed density and dry weight considerably than CT. CA- based systems led to significantly higher wheat grain yield (by 11.6–14.9%) and net B:C (by 24.0 –28.0%) than CT, and PFBR100N and PBBR100N were slightly superior to others. PBBR100N and PBBR75N had lower irrigation water use and significantly higher irrigation water productivity than CT. Contrast analysis showed that wheat yield and water productivity were comparable between 75% N and 100% N in CA, indicating a saving of 25% N under CA

    Extensive Gene-Specific Translational Reprogramming in a Model of B Cell Differentiation and Abl-Dependent Transformation

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    To what extent might the regulation of translation contribute to differentiation programs, or to the molecular pathogenesis of cancer? Pre-B cells transformed with the viral oncogene v-Abl are suspended in an immortalized, cycling state that mimics leukemias with a BCR-ABL1 translocation, such as Chronic Myelogenous Leukemia (CML) and Acute Lymphoblastic Leukemia (ALL). Inhibition of the oncogenic Abl kinase with imatinib reverses transformation, allowing progression to the next stage of B cell development. We employed a genome-wide polysome profiling assay called Gradient Encoding to investigate the extent and potential contribution of translational regulation to transformation and differentiation in v-Abl-transformed pre-B cells. Over half of the significantly translationally regulated genes did not change significantly at the level of mRNA abundance, revealing biology that might have been missed by measuring changes in transcript abundance alone. We found extensive, gene-specific changes in translation affecting genes with known roles in B cell signaling and differentiation, cancerous transformation, and cytoskeletal reorganization potentially affecting adhesion. These results highlight a major role for gene-specific translational regulation in remodeling the gene expression program in differentiation and malignant transformation

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Chapter 11 - Development of a coupled physical–computational methodology for the investigation of infant head injury

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    Establishing whether an infant’s traumatic head injury results from an accidental or nonaccidental, abusive cause is a fundamental question in forensic investigations. Often practitioners are provided with either “no explanation” of the cause of the presenting injuries or only a brief description of a causal event, and therefore, struggle to establish a sufficiently detailed understanding of a cause-and-effect relationship with which to make a differential diagnosis. The head may be injured by many different mechanisms. Therefore, developing a necessary knowledge of the cause from practical experience and epidemiology alone is a significant challenge since there are very many biomechanical variables that require consideration. Experimentation with living infants is impossible, and infant cadaver availability is limited and problematic, and hence, modeling is an obvious path. Presented is the development of a coupled physical–computational modeling methodology for the investigation of infant head injury. A physical surrogate infant head was created from high-resolution computer tomography scans with tissue material properties closely matched to tissue response data. An infant skull was 3D-printed from co-polymer materials and the brain, represented as a lumped mass, comprised of an injected gelatin/water mix. Experimental head impact responses were validated against Postmortem human surrogate (PMHS) head impact acceleration data. High speed digital image correlation optically measured linear and angular velocities and accelerations, strains, and strain rates. The “global approximation,” derived from the PMHS head impact acceleration data, was challenged by comparing regional and local acceleration data. The validated physical infant head surrogate, producing “real world” global, regional, and localized impact response data, was used to inform a computational finite element-head copy of the physical head model that was validated against the PMHS and physical model global impact response data. Experimental impact simulations were performed to investigate regional and localized injury vulnerability. Different regions of the head produced accelerations significantly greater than those calculated using the currently available method of measuring the “global” physical whole head response. The majority of material strain was produced within the relatively elastic suture and fontanelle regions rather than the skull bones. A subsequent parametric analysis was conducted to provide a correlation between fall height and areas of the maximum stress response. The coupled methodology shows significant potential for the study of infant head injury and is anticipated to be a motivating tool for the improvement of head injury understanding across a range of potentially injurious head loading scenarios. The methodology has proven a significant new step in characterizing and understanding infant head injury mechanics
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