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The effort for combating the COVID-19 pandemic around the world has resulted in a huge amount of data, e.g., from testing, contact tracing, modelling, treatment, vaccine trials, and more. In addition to numerous challenges in epidemiology, healthcare, biosciences, and social sciences, there has been an urgent need to develop and provide visualisation and visual analytics (VIS) capacities to support emergency responses under difficult operational conditions. In this paper, we report the experience of a group of VIS volunteers who have been working in a large research and development consortium and providing VIS support to various observational, analytical, model-developmental, and disseminative tasks. In particular, we describe our approaches to the challenges that we have encountered in requirements analysis, data acquisition, visual design, software design, system development, team organisation, and resource planning. By reflecting on our experience, we propose a set of recommendations as the first step towards a methodology for developing and providing rapid VIS capacities to support emergency responses.
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COVID-19 , COVID-19/epidemiologia , Busca de Comunicante , Humanos , PandemiasRESUMO
Cardiac stroke volume (SV) is compromised in Atlantic cod and rainbow trout following acclimation to hypoxia (i.e., 40% air saturation; ~8 kPa O2) at 10-12°C, and this is not due to changes in heart morphometrics or maximum achievable in vitro end-diastolic volume. To examine if this diminished SV may be related to compromised myocardial contractility, we used the work-loop method to measure work and power in spongy myocardial strips from normoxic- and hypoxic-acclimated steelhead trout when exposed to decreasing Po2 levels (21 to 1.5 kPa) at several frequencies (30-90 contractions/min) at 14°C (their acclimation temperature). Work required to lengthen the muscle, as during filling of the heart, was strongly frequency dependent (i.e., increased with contraction rate) but was not affected by hypoxic acclimation or test Po2. In contrast, although shortening work was less frequency dependent, this parameter and network (and power) 1) were consistently lower (by ~30-50 and ~15%, respectively) in strips from hypoxic-acclimated fish and 2) fell by ~40-50% in both groups from 20 to 1.5 kPa Po2, despite the already-reduced myocardial performance in the hypoxic-acclimated group. In addition, strips from hypoxic-acclimated trout showed a poorer recovery of net power (by ~15%) when returned to normoxia. These results strongly suggest that hypoxic acclimation reduces myocardial contractility, and in turn, may limit SV (possibly by increasing end-systolic volume), but that this diminished performance does not improve the capacity to maintain myocardial performance under oxygen limiting conditions.
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Aclimatação , Cardiopatias/etiologia , Hipóxia/complicações , Contração Miocárdica , Oncorhynchus mykiss/sangue , Oxigênio/sangue , Volume Sistólico , Animais , Biomarcadores/sangue , Feminino , Cardiopatias/sangue , Cardiopatias/fisiopatologia , Hipóxia/sangue , Hipóxia/fisiopatologia , Técnicas In Vitro , Fatores de TempoRESUMO
Pork bellies (nâ¯=â¯198) were scanned with dual energy X-ray absorptiometry (DXA). Visible and near-infrared reflectance (Vis-NIR) spectra were collected from the lean (latissimus dorsi), subcutaneous fat and intermuscular fat layers. Belly-flop angle and subjective belly scores were collected as measures of pork belly softness. Vis-NIR spectra from a single fat layer could explain between 72.7 and 81.1% of the variation in pork belly softness (43.6-72.4% in validation set). The combination of the lean and subcutaneous layers improved the calibration model fit to 79.7-99.9% (66.3-71.5% in validation set). The DXA estimates explained 62.3% of variation in pork belly softness (65.2% in validation set). Results indicated that DXA and NIR technologies could potentially be utilized for pork belly softness sorting in the pork industry.
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Absorciometria de Fóton/métodos , Carne Vermelha/análise , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Animais , Feminino , Masculino , Gordura Subcutânea , Músculos Superficiais do Dorso , Sus scrofaRESUMO
INTRODUCTION: To address the need for a patient-reported outcome that can measure clinically and personally meaningful change in people with haemophilia (PwH) on prophylaxis, an approach based on Goal Attainment Scaling (GAS) was developed: the GAS-Hem. AIM: To establish real-world feasibility of GAS-Hem in PwH. METHODS: Patients aged 5-65 years were enroled from four North American centres for a 12-week study. The primary outcome was the proportion of participants who completed GAS-Hem interviews at baseline, 6 and 12 weeks. GAS-Hem scores were obtained by subject- and clinician-rated goal attainment at Weeks 6 and 12, and compared with quality of life (QoL) measures and annualized bleed rate (ABR) for construct validity. Goals were evaluated qualitatively for content validity. Responsiveness was calculated using standardized response means (SRM). RESULTS: Forty-two participants set 63 goals. Participants preferred to define (37/63) their own goals or further individualize (23/63) from the GAS-Hem menu. Thirty of the 37 self-defined goals were matched to goals on the GAS-Hem menu. The most common goal areas were: weight, exercise and nutrition (n = 17); leisure activities (n = 8); and joint problems (n = 7). Both participant- and clinician-rated GAS-Hem scores at 6 weeks (n = 40) and 12 weeks (n = 41) demonstrated satisfactory goal attainment (SRM [subject-rated] at 12 weeks for adult and paediatric groups was 1.25 and 1.16, respectively). Correlations of GAS-Hem scores with QoL measures and ABR were uniformly small. CONCLUSION: GAS-Hem was feasible and tapped constructs not captured by ABR or QoL measures.
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Objetivos , Hemofilia A/diagnóstico , Avaliação de Resultados em Cuidados de Saúde/métodos , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Qualidade de Vida , Fatores de Tempo , Adulto JovemRESUMO
Consumption of central nervous system tissue (CNST) from cattle with bovine spongiform encephalopathy (BSE) is thought to cause the human neurological disease, variant Creutzfeldt-Jacob disease. To identify points of cross-contamination of beef carcasses with CNST, 55 young beef cattle were slaughtered and processed through a federally inspected multispecies abattoir. The objectives of this study were to evaluate CNST spread following the placement of a plug in the penetration site of the skull after captive bolt stunning, to evaluate cross-contamination of carcasses before and after splitting, to compare the effects of hot water pasteurization (84°C for 10 s) versus cold water wash (10°C for 30 s) for reducing CNST on the carcass, and to examine other possible sources of cross-contamination in the abattoir. Results indicated that the use of a plastic plug reduced CNST contamination near the bolt penetration site. This study also confirmed that carcass splitting resulted in an increase in CNST contamination at various areas of the carcass. Hot water pasteurization appeared to be an effective means of removing CNST contamination from carcasses in most of the areas sampled.
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Contaminação de Alimentos , Carne Vermelha , Matadouros , Animais , Bovinos , Sistema Nervoso Central , Encefalopatia Espongiforme Bovina , Humanos , CarneRESUMO
INTRODUCTION: A recombinant porcine factor VIII B-domain-deleted product (rpFVIII; OBIZUR, Baxalta Incorporated, Deerfield, IL 60015, USA) was recently approved for treatment of bleeding episodes in adults with acquired haemophilia A (AHA) in the United States. To date, no clinical experience outside the registration study has been reported. AIM: To describe early clinical experience using rpFVIII for AHA. METHODS: A retrospective chart review of seven patients with AHA treated with rpFVIII at four institutions from November 2014 to October 2015. RESULTS: The time to diagnosis of AHA ranged from 5 days to 6 weeks. Six major and one other bleed were treated with rpFVIII following unsatisfactory bypassing agent (BPA) therapy. Good haemostatic efficacy was seen in five of seven cases. rpFVIII loading doses of 100 (n = 6) or 200 U kg-1 (n = 1) increased FVIII activity from <1 to 9% at baseline to 109-650% within 0.25-7 h in six of seven cases. Subsequent median doses ranged from 30 to 100 U kg-1 for 3-26 days. No rpFVIII-related adverse events were reported. Three patients survived with inhibitor eradication, one with persistent inhibitor, two died with inhibitors present and one was discharged and later died from unrelated causes. CONCLUSIONS: rpFVIII showed good haemostatic efficacy with no recurrences in most cases, with consumption substantially less than in the registration study. Treatment decisions were based on FVIII activity levels and clinical assessment. The ability to titrate rpFVIII dose using FVIII activity was considered advantageous compared with BPA therapy. Notable delays in diagnosis were observed.
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Hemofilia A/terapia , Proteínas Recombinantes/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Animais , Feminino , Hemofilia A/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Suínos , Resultado do Tratamento , Adulto JovemRESUMO
Von Willebrand disease (VWD) is considered the most common inherited bleeding disorder and may also be the most difficult to diagnose. Clinical symptoms of VWD include predominantly mild mucosal bleeding; surgical bleeding may occur with specific challenges and joint bleeding can occur in the most severe forms. A family history either of diagnosed VWD or of bleeding symptoms is typically present. Laboratory diagnosis requires a series of assays of von Willebrand factor (VWF) quantity and function, and factor VIII activity, with no single straightforward diagnostic test available to either confirm or exclude the diagnosis. Newer assays of VWF function are becoming more available and useful in determining the laboratory diagnosis of VWD.
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Técnicas de Laboratório Clínico/métodos , Fator VIII/metabolismo , Doenças de von Willebrand/diagnóstico , Fator de von Willebrand/metabolismo , Humanos , Reprodutibilidade dos Testes , Ristocetina/metabolismo , Sensibilidade e Especificidade , Doenças de von Willebrand/sangue , Doenças de von Willebrand/classificaçãoRESUMO
The skull-brain complex is typically modeled as an integrated structure, similar to a fluid-filled shell. Under dynamic loads, the interaction of the skull and the underlying brain, cerebrospinal fluid, and other tissue produces the pressure and strain histories that are the basis for many theories meant to describe the genesis of traumatic brain injury. In addition, local bone strains are of interest for predicting skull fracture in blunt trauma. However, the role of skull flexure in the intracranial pressure response to blunt trauma is complex. Since the relative time scales for pressure and flexural wave transmission across the skull are not easily separated, it is difficult to separate out the relative roles of the mechanical components in this system. This study uses a finite element model of the head, which is validated for pressure transmission to the brain, to assess the influence of skull table flexural stiffness on pressure in the brain and on strain within the skull. In a Human Head Finite Element Model, the skull component was modified by attaching shell elements to the inner and outer surfaces of the existing solid elements that modeled the skull. The shell elements were given the properties of bone, and the existing solid elements were decreased so that the overall stiffness along the surface of the skull was unchanged, but the skull table bending stiffness increased by a factor of 2.4. Blunt impact loads were applied to the frontal bone centrally, using LS-Dyna. The intracranial pressure predictions and the strain predictions in the skull were compared for models with and without surface shell elements, showing that the pressures in the mid-anterior and mid-posterior of the brain were very similar, but the strains in the skull under the loads and adjacent to the loads were decreased 15% with stiffer flexural properties. Pressure equilibration to nearly hydrostatic distributions occurred, indicating that the important frequency components for typical impact loading are lower than frequencies based on pressure wave propagation across the skull. This indicates that skull flexure has a local effect on intracranial pressures but that the integrated effect of a dome-like structure under load is a significant part of load transfer in the skull in blunt trauma.
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Since 2000, the Department of Defense has documented more than 253,000 cases of Traumatic Brain Injury (TBI). A significant portion of these injuries were attributed to explosive events, yet ninety-eight percent were non-penetrating. Understanding the response of the brain to blast events is critical, yet the mechanisms of brain injury from explosive trauma are poorly understood. This knowledge gap has led to an increased research focus on devices capable of investigating human brain response to non-penetrating, blast-induced loading. Furthermore, traumatic brain injury is a major issue for the civilian population as well with over 1.7 million cases of TBI per year in the US, primarily from falls and motor vehicle accidents. Current head surrogates and instrumentation are incapable of directly measuring critical parameters associated with TBI, such as brain motion, during dynamic loading. To this end, a novel sensor system for measuring brain motion inside of a human head surrogate was conceptualized and developed. The positioning system is comprised of a set of three fixed generator coils and a plurality of mobile, miniaturized receiver coil triads. Each generator coil transmits a sinusoidal electromagnetic signal at a unique frequency, and groups of three orthogonally arranged receiver coils detect these signals. Because of the oscillatory nature of these signals, the magnetic flux through the coil is always changing, allowing the application of Faradays Law of Induction and the point dipole model of an electric field to model the strength and direction of the field vector at any given point. Thus, the strength of the signal measured by a particular receiver coil depends on its position and orientation relative to the fixed position of the generators. These predictable changes are used to determine the six degrees of freedom (6-DOF) motion of the receiver. To calibrate and validate the system, a receiver coil was moved about in a controlled manner, and its actual position recorded by optical methods. Comparing the known position to the computed position at each time instance, a set of calibration constants were developed for each receiver triad. These constants were then utilized to convert receiver signal data into actual receiver position and orientation. Comparing this test case and several others like it, mean error was determined to be almost always less than 1.0 mm, and less than 0.5 mm >85% of the time. Additionally, high rate validation was conducted to confirm operation of the system in the impact domain. A coil was accelerated to approximately 15 m/sec along a fixed axis by ballistic impact and tracked by high speed video. The computed position was within 1 mm of the actual position 93% of the time and within 0.5 mm 83% of the time. The successful development and calibration of this sensing system now enables the direct measurements of brain displacement due to mechanical insults applied to a human head surrogate.
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A human head finite element model (HHFEM) was developed to study the effects of a blast to the head. To study both the kinetic and kinematic effects of a blast wave, the HHFEM was attached to a finite element model of a Hybrid III ATD neck. A physical human head surrogate model (HSHM) was developed from solid model files of the HHFEM, which was then attached to a physical Hybrid III ATD neck and exposed to shock tube overpressures. This allowed direct comparison between the HSHM and HHFEM. To develop the temporal and spatial pressures on the HHFEM that would simulate loading to the HSHM, a computational fluid dynamics (CFD) model of the HHFEM in front of a shock tube was generated. CFD simulations were made using loads equivalent to those seen in experimental studies of the HSHM for shock tube driver pressures of 517, 690 and 862 kPa. Using the selected brain material properties, the peak intracranial pressures, temporal and spatial histories of relative brain-skull displacements and the peak relative brain-skull displacements in the brain of the HHFEM compared favorably with results from the HSHM. The HSHM sensors measured the rotations of local areas of the brain as well as displacements, and the rotations of the sensors in the sagittal plane of the HSHM were, in general, correctly predicted from the HHFEM. Peak intracranial pressures were between 70 and 120 kPa, while the peak relative brain-skull displacements were between 0.5 and 3.0mm.
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Traumatismos por Explosões/fisiopatologia , Cabeça/fisiopatologia , Modelos Biológicos , Pescoço/fisiopatologia , Fenômenos Biomecânicos , Simulação por Computador , Elasticidade , Análise de Elementos Finitos , Humanos , Hidrodinâmica , Pressão , ViscosidadeAssuntos
Antagonistas dos Receptores H2 da Histamina/uso terapêutico , Úlcera Péptica/prevenção & controle , Inibidores da Bomba de Prótons/uso terapêutico , Estresse Psicológico/complicações , Antagonistas dos Receptores H2 da Histamina/administração & dosagem , Antagonistas dos Receptores H2 da Histamina/efeitos adversos , Humanos , Úlcera Péptica/tratamento farmacológico , Úlcera Péptica/etiologia , Inibidores da Bomba de Prótons/administração & dosagem , Inibidores da Bomba de Prótons/efeitos adversos , Fatores de RiscoRESUMO
Modeling human body response to dynamic loading events and developing biofidelic human surrogate systems require accurate material properties over a range of loading rates for various human organ tissues. This work describes a technique for measuring the shear properties of soft biomaterials at high rates of strain (100-1000 s(-1)) using a modified split Hopkinson pressure bar (SHPB). Establishing a uniform state of stress in the sample is a fundamental requirement for this type of high-rate testing. Input pulse shaping was utilized to tailor and control the ramping of the incident loading pulse such that a uniform stress state could be maintained within the specimen from the start of the test. Direct experimental verification of the stress uniformity in the sample was obtained via comparison of the force measured by piezoelectric quartz force gages on both the input and the output sides of the shear specimen. The technique was demonstrated for shear loading of silicone gel biosimulant materials and porcine brain tissue. Finite element simulations were utilized to further investigate the effect of pulse shaping on the loading rate and rise time. Simulations also provided a means for visualization of the degree of shear stress and strain uniformity in the specimen during an experiment. The presented technique can be applied to verify stress uniformity and ensure high quality data when measuring the dynamic shear modulus of soft biological simulants and tissue.
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Materiais Biomiméticos , Análise de Elementos Finitos , Teste de Materiais/instrumentação , Pressão , Animais , Encéfalo/citologia , Resistência ao Cisalhamento , Estresse MecânicoRESUMO
BACKGROUND AND PURPOSE: Histamine H3 receptor antagonists are currently being evaluated in clinical trials for a number of central nervous system disorders including narcolepsy. These agents can increase wakefulness (W) in cats and rodents following acute administration, but their effects after repeat dosing have not been reported previously. EXPERIMENTAL APPROACH: EEG and EMG recordings were used to investigate the effects of acute and repeat administration of the novel H3 antagonist GSK189254 on the sleep-wake cycle in wild-type (Ox+/+) and orexin knockout (Ox-/-) mice, the latter being genetically susceptible to narcoleptic episodes. In addition, we investigated H3 and H1 receptor expression in this model using radioligand binding and autoradiography. KEY RESULTS: In Ox+/+ and Ox-/- mice, acute administration of GSK189254 (3 and 10 mg x kg(-1) p.o.) increased W and decreased slow wave and paradoxical sleep to a similar degree to modafinil (64 mg x kg(-1)), while it reduced narcoleptic episodes in Ox-/- mice. After twice daily dosing for 8 days, the effect of GSK189254 (10 mg x kg(-1)) on W in both Ox+/+ and Ox-/- mice was significantly reduced, while the effect on narcoleptic episodes in Ox-/- mice was significantly increased. Binding studies revealed no significant differences in H3 or H1 receptor expression between Ox+/+ and Ox-/- mice. CONCLUSIONS AND IMPLICATIONS: These studies provide further evidence to support the potential use of H3 antagonists in the treatment of narcolepsy and excessive daytime sleepiness. Moreover, the differential effects observed on W and narcoleptic episodes following repeat dosing could have important implications in clinical studies.
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Benzazepinas/farmacologia , Antagonistas dos Receptores Histamínicos H3/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Narcolepsia/tratamento farmacológico , Neuropeptídeos/genética , Niacinamida/análogos & derivados , Sono/efeitos dos fármacos , Vigília/efeitos dos fármacos , Animais , Autorradiografia , Benzazepinas/administração & dosagem , Benzazepinas/uso terapêutico , Compostos Benzidrílicos/farmacologia , Encéfalo/metabolismo , Relação Dose-Resposta a Droga , Eletroencefalografia , Eletromiografia , Antagonistas dos Receptores Histamínicos H3/administração & dosagem , Antagonistas dos Receptores Histamínicos H3/uso terapêutico , Camundongos , Camundongos Knockout , Modafinila , Narcolepsia/genética , Niacinamida/administração & dosagem , Niacinamida/farmacologia , Niacinamida/uso terapêutico , Orexinas , Ensaio Radioligante , Receptores Histamínicos H3/metabolismoRESUMO
BACKGROUND AND PURPOSE: Histamine H3 receptor antagonists are currently being evaluated for their potential use in a number of central nervous system disorders including Alzheimer's Disease (AD). To date, little is known about the state of H3 receptors in AD. EXPERIMENTAL APPROACH: In the present study we used the radiolabelled H3 receptor antagonist [3H]GSK189254 to investigate H3 receptor binding in the amyloid over-expressing double mutant APPswe x PSI.MI46V (TASTPM) transgenic mouse model of AD and in post-mortem human AD brain samples. KEY RESULTS: No significant differences in specific H3 receptor binding were observed between wild type and TASTPM mice in the cortex, hippocampus or hypothalamus. Specific [3H]GSK189254 binding was detected in sections of human medial frontal cortex from AD brains of varying disease severity (Braak stages I-VI). With more quantitative analysis in a larger cohort, we observed that H3 receptor densities were not significantly different between AD and age-matched control brains in both frontal and temporal cortical regions. However, within the AD group, [3H]GSK189254 binding density in frontal cortex was higher in individuals with more severe dementia prior to death. CONCLUSIONS AND IMPLICATIONS: The maintenance of H3 receptor integrity observed in the various stages of AD in this study is important, given the potential use of H3 antagonists as a novel therapeutic approach for the symptomatic treatment of AD.
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Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/biossíntese , Encéfalo/metabolismo , Receptores Histamínicos H3/metabolismo , Idoso , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Autorradiografia , Benzazepinas/farmacologia , Encéfalo/patologia , Feminino , Antagonistas dos Receptores Histamínicos H3/farmacologia , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Mutação , Neocórtex/metabolismo , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Ensaio Radioligante , Índice de Gravidade de DoençaRESUMO
The dynamic response of soft human tissues in hydrostatic compression and simple shear is studied using the Kolsky bar technique. We have made modifications to the technique that allow loading of a soft tissue specimen in hydrostatic compression or simple shear. The dynamic response of human tissues (from stomach, heart, liver, and lung of cadavers) is obtained, and analyzed to provide measures of dynamic bulk modulus and shear response for each tissue type. The dynamic bulk response of these tissues is easily described by a linear fit for the bulk modulus in this pressure range, whereas the dynamic shearing response of these tissues is strongly non-linear, showing a near exponential growth of the shear stress.
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Fenômenos Biomecânicos , Fígado , Pulmão , Miocárdio , Estômago , Adolescente , Adulto , Força Compressiva , Humanos , Resistência ao Cisalhamento , Estresse MecânicoRESUMO
Both computational finite element and experimental models of the human torso have been developed for ballistic impact testing. The human torso finite element model (HTFEM), including the thoracic skeletal structure and organs, was created in the finite element code LS-DYNA. The skeletal structure was assumed to be linear-elastic while all internal organs were modeled as viscoelastic. A physical human surrogate torso model (HSTM) was developed using biosimulant materials and the same anthropometry as the HTFEM. The HSTM response to impact was recorded with piezoresistive pressure sensors molded into the heart, liver and stomach and an accelerometer attached to the sternum. For experimentation, the HSTM was outfitted with National Institute of Justice (NIJ) Level I, IIa, II and IIIa soft armor vests. Twenty-six ballistic tests targeting the HSTM heart and liver were conducted with 22 caliber ammunition at a velocity of 329 m/s and 9 mm ammunition at velocities of 332, 358 and 430 m/s. The HSTM pressure response repeatability was found to vary by less than 10% for similar impact conditions. A comparison of the HSTM and HTFEM response showed similar pressure profiles and less than 35% peak pressure difference for organs near the ballistic impact point. Furthermore, the peak sternum accelerations of the HSTM and HTFEM varied by less than 10% for impacts over the sternum. These models provide comparative tools for determining the thoracic response to ballistic impact and could be used to evaluate soft body armor design and efficacy, determine thoracic injury mechanisms and assist with injury prevention.
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Balística Forense , Fenômenos Biomecânicos , Análise de Elementos Finitos , Balística Forense/estatística & dados numéricos , Humanos , Modelos Anatômicos , Modelos Biológicos , Modelos Estatísticos , Traumatismos Torácicos/etiologia , Traumatismos Torácicos/fisiopatologia , Tórax/anatomia & histologiaRESUMO
AIMS: The aims of this study were to identify analogues of L-proline which inhibit the growth of Escherichia coli in both laboratory culture media and normal human urine and to study their mechanisms of uptake. METHODS AND RESULTS: The susceptibility of E. coli to L-proline analogues was studied by radial streak assays on agar plates and by minimal inhibitory concentration determinations in liquid media. Only L-selenaproline (SCA) inhibited growth in Mueller-Hinton medium and human urine as well as in glucose minimal medium. L-Proline did not prevent the inhibition of growth by SCA and strains defective in L-proline transport were as susceptible to SCA as wild-type strains. However, E. coli was resistant to SCA in the presence of L-cysteine and L-cystine. Spontaneous mutants selected for resistance to SCA or L-selenocystine were resistant to the other compound and had reduced growth in minimal medium containing L-cysteine or L-cystine as the sole sulfur source. CONCLUSIONS: L-selenaproline inhibited the growth of E. coli under conditions that may occur in the urinary tract and appeared to be taken up by the L-cystine transport system. SIGNIFICANCE AND IMPACT OF THE STUDY: Although urinary tract infections caused by E. coli can be treated with sulfamethoxazole/trimethoprim and quinolones, resistance to these antibiotics has been increasing. These results suggest that L-selenaproline may represent a new class of compounds that could be used to treat these infections.
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Escherichia coli/efeitos dos fármacos , Compostos Organosselênicos/farmacologia , Prolina/análogos & derivados , Técnicas Bacteriológicas/métodos , Meios de Cultura/metabolismo , Meios de Cultura/farmacologia , Cisteína/metabolismo , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Humanos , Testes de Sensibilidade Microbiana , Compostos Organosselênicos/química , Compostos Organosselênicos/urina , Prolina/química , Prolina/farmacologia , Prolina/urinaRESUMO
The dependence of optical modal gain and loss on GaN:Eu growth temperature is reported. GaN:Eu thin films were grown on Si substrates with AlGaN transition and cladding layers at temperatures ranging from 600 degrees C to 850 degrees C. The modal gain and loss in the GaN:Eu layer were a strong function of the optically active Eu atomic concentration and of the interface quality between the active layer and the top cladding layer, which in turn depended on the growth temperature. Optimum optical properties of maximum modal gain of ~ 100 cm(-1) and minimum loss of ~ 46 cm(-1) were obtained for growth at 800 degrees C.
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We are carrying out studies aimed at reducing the mutagenic effects of high-LET 56Fe ions and 12C ions (56Fe ions, 143 keV/microm; 12C ions, 100 keV/microm) with certain drugs, including RibCys [2-(R,S)-D-ribo-(1',2',3',4'-tetrahydroxybutyl)-thiazolidine-4(R)-carboxylic acid]. RibCys, formed by condensation of L-cysteine with D-ribose, is designed so that the sulfhydryl amino acid L-cysteine is released intracellularly through nonenzymatic ring opening and hydrolysis leading to increased levels of glutathione (GSH). RibCys (4 or 10 mM), which was present during irradiation and for a few hours after, significantly decreased the yield of CD59- mutants induced by radiation in AL human-hamster hybrid cells. RibCys did not affect the clonogenic survival of irradiated cells, nor was it mutagenic itself. These results, together with the minimal side effects reported in mice and pigs, indicate that RibCys may be useful, perhaps even when used prophylactically, in reducing the mutation load created by high-LET radiation in astronauts or other exposed individuals.
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Radioisótopos de Carbono , Radioisótopos de Ferro , Transferência Linear de Energia , Mutação/efeitos dos fármacos , Tolerância a Radiação/efeitos dos fármacos , Tiazóis/farmacologia , Animais , Células CHO , Contagem de Células , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Cricetinae , Cricetulus , Cisteína/análogos & derivados , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Humanos , Células Híbridas/citologia , Células Híbridas/efeitos dos fármacos , Células Híbridas/efeitos da radiação , Linfócitos/citologia , Linfócitos/efeitos dos fármacos , Linfócitos/efeitos da radiação , Pró-Fármacos/farmacologia , Doses de Radiação , Protetores contra Radiação/farmacologia , TiazolidinasRESUMO
BACKGROUND: High resistance training enhances muscular strength, and recent work has suggested an important role for metabolite accumulation in this process. OBJECTIVE: To investigate the role of fatigue and metabolite accumulation in strength gains by comparing highly fatiguing and non-fatiguing isotonic training protocols. METHODS: Twenty three healthy adults (18-29 years of age; eight women) were assigned to either a high fatigue protocol (HF: four sets of 10 repetitions with 30 seconds rest between sets) to maximise metabolic stress or a low fatigue protocol (LF: 40 repetitions with 30 seconds between each repetition) to minimise changes. Subjects lifted on average 73% of their 1 repetition maximum through the full range of knee extension with both legs, three times a week. Quadriceps isometric strength of each leg was measured at a knee joint angle of 1.57 rad (90 degrees ), and a Cybex 340 isokinetic dynamometer was used to measure the angle-torque and torque-velocity relations of the non-dominant leg. RESULTS: At the mid-point of the training, the HF group had 50% greater gains in isometric strength, although this was not significant (4.5 weeks: HF, 13.3 (4.4)%; LF, 8.9 (3.6)%). This rate of increase was not sustained by the HF group, and after nine weeks of training all the strength measurements showed similar improvements for both groups (isometric strength: HF, 18.2 (3.9)%; LF, 14.5 (4.0)%). The strength gains were limited to the longer muscle lengths despite training over the full range of movement. CONCLUSIONS: Fatigue and metabolite accumulation do not appear to be critical stimuli for strength gain, and resistance training can be effective without the severe discomfort and acute physical effort associated with fatiguing contractions.