73 research outputs found

    Release angle for attaining maximum distance in the soccer throw-in

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    We investigated the release angle that maximises the distance attained in a long soccer throw-in. One male soccer player performed maximum-effort throws using release angles of between 10 and 60º, and the throws were analysed using two-dimensional videography. The player’s optimum release angle was calculated by substituting mathematical expressions for the measured relationships between release speed, release height and release angle into the equations for the flight of a spherical projectile. We found that the musculoskeletal structure of the player’s body had a strong influence on the optimum release angle. When using low release angles the player released the ball with a greater release speed and, because the range of a projectile is strongly dependent on the release speed, this bias toward low release angles reduced the optimum release angle to about 30°. Calculations showed that the distance of a throw may be increased by a few metres by launching the ball with a fast backspin, but the ball must be launched at a slightly lower release angle

    Photographed Rapid HIV Test Results Pilot Novel Quality Assessment and Training Schemes

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    HIV rapid diagnostic tests (RDTs) are now used widely in non-laboratory settings by non-laboratory-trained operators. Quality assurance programmes are essential in ensuring the quality of HIV RDT outcomes. However, there is no cost-effective means of supplying the many operators of RDTs with suitable quality assurance schemes. Therefore, it was examined whether photograph-based RDT results could be used and correctly interpreted in the non-laboratory setting. Further it was investigated if a single training session improved the interpretation skills of RDT operators. The photographs were interpreted, a 10-minute tutorial given and then a second interpretation session was held. It was established that the results could be read with accuracy. The participants (n = 75) with a range of skills interpreted results (>80% concordance with reference results) from a panel of 10 samples (three negative and seven positive) using four RDTs. Differences in accuracy of interpretation before and after the tutorial were marked in some cases. Training was more effective for improving the accurate interpretation of more complex results, e.g. results with faint test lines or for multiple test lines, and especially for improving interpretation skills of inexperienced participants. It was demonstrated that interpretation of RDTs was improved using photographed results allied to a 10-minute training session. It is anticipated that this method could be used for training but also for quality assessment of RDT operators without access to conventional quality assurance or training schemes requiring wet samples

    Determination of nitric oxide metabolites, nitrate and nitrite, in Anopheles culicifacies mosquito midgut and haemolymph by anion exchange high-performance liquid chromatography: plausible mechanism of refractoriness

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    <p>Abstract</p> <p>Background</p> <p>The diverse physiological and pathological role of nitric oxide in innate immune defenses against many intra and extracellular pathogens, have led to the development of various methods for determining nitric oxide (NO) synthesis. NO metabolites, nitrite (NO<sub>2</sub><sup>-</sup>) and nitrate (NO<sub>3</sub><sup>-</sup>) are produced by the action of an inducible <it>Anopheles culicifacies </it>NO synthase (AcNOS) in mosquito mid-guts and may be central to anti-parasitic arsenal of these mosquitoes.</p> <p>Method</p> <p>While exploring a plausible mechanism of refractoriness based on nitric oxide synthase physiology among the sibling species of <it>An. culicifacies</it>, a sensitive, specific and cost effective high performance liquid chromatography (HPLC) method was developed, which is not influenced by the presence of biogenic amines, for the determination of NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>from mosquito mid-guts and haemolymph.</p> <p>Results</p> <p>This method is based on extraction, efficiency, assay reproducibility and contaminant minimization. It entails de-proteinization by centrifugal ultra filtration through ultracel 3 K filter and analysis by high performance anion exchange liquid chromatography (Sphereclone, 5 μ SAX column) with UV detection at 214 nm. The lower detection limit of the assay procedure is 50 pmoles in all midgut and haemolymph samples. Retention times for NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>in standards and in mid-gut samples were 3.42 and 4.53 min. respectively. Assay linearity for standards ranged between 50 n<it>M </it>and 1 m<it>M</it>. Recoveries of NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>from spiked samples (1–100 μ<it>M</it>) and from the extracted standards (1–100 μ<it>M</it>) were calculated to be 100%. Intra-assay and inter assay variations and relative standard deviations (RSDs) for NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>in spiked and un-spiked midgut samples were 5.7% or less. Increased levels NO<sub>2</sub><sup>- </sup>and NO<sub>3</sub><sup>- </sup>in midguts and haemolymph of <it>An. culicifacies </it>sibling species B in comparison to species A reflect towards a mechanism of refractoriness based on AcNOS physiology.</p> <p>Conclusion</p> <p>HPLC is a sensitive and accurate technique for identification and quantifying pmole levels of NO metabolites in mosquito midguts and haemolymph samples that can be useful for clinical investigations of NO biochemistry, physiology and pharmacology in various biological samples.</p

    The Herpes Simplex Virus-1 Transactivator Infected Cell Protein-4 Drives VEGF-A Dependent Neovascularization

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    Herpes simplex virus-1 (HSV-1) causes lifelong infection affecting between 50 and 90% of the global population. In addition to causing dermal lesions, HSV-1 is a leading cause of blindness resulting from recurrent corneal infection. Corneal disease is characterized by loss of corneal immunologic privilege and extensive neovascularization driven by vascular endothelial growth factor-A (VEGF-A). In the current study, we identify HSV-1 infected cells as the dominant source of VEGF-A during acute infection, and VEGF-A transcription did not require TLR signaling or MAP kinase activation. Rather than being an innate response to the pathogen, VEGF-A transcription was directly activated by the HSV-1 encoded immediate early transcription factor, ICP4. ICP4 bound the proximal human VEGF-A promoter and was sufficient to promote transcription. Transcriptional activation also required cis GC-box elements common to the VEGF-A promoter and HSV-1 early genes. Our results suggest that the neovascularization characteristic of ocular HSV-1 disease is a direct result of HSV-1's major transcriptional regulator, ICP4, and similarities between the VEGF-A promoter and those of HSV-1 early genes

    Regulated acid-base transport in the collecting duct

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    The renal collecting system serves the fine-tuning of renal acid-base secretion. Acid-secretory type-A intercalated cells secrete protons via a luminally expressed V-type H(+)-ATPase and generate new bicarbonate released by basolateral chloride/bicarbonate exchangers including the AE1 anion exchanger. Efficient proton secretion depends both on the presence of titratable acids (mainly phosphate) and the concomitant secretion of ammonia being titrated to ammonium. Collecting duct ammonium excretion requires the Rhesus protein RhCG as indicated by recent KO studies. Urinary acid secretion by type-A intercalated cells is strongly regulated by various factors among them acid-base status, angiotensin II and aldosterone, and the Calcium-sensing receptor. Moreover, urinary acidification by H(+)-ATPases is modulated indirectly by the activity of the epithelial sodium channel ENaC. Bicarbonate secretion is achieved by non-type-A intercalated cells characterized by the luminal expression of the chloride/bicarbonate exchanger pendrin. Pendrin activity is driven by H(+)-ATPases and may serve both bicarbonate excretion and chloride reabsorption. The activity and expression of pendrin is regulated by different factors including acid-base status, chloride delivery, and angiotensin II and may play a role in NaCl retention and blood pressure regulation. Finally, the relative abundance of type-A and non-type-A intercalated cells may be tightly regulated. Dysregulation of intercalated cell function or abundance causes various syndromes of distal renal tubular acidosis underlining the importance of these processes for acid-base homeostasis

    Quinolone-resistant Salmonella typhi in Viet Nam: molecular basis of resistance and clinical response to treatment.

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    Nalidixic acid-resistant Salmonella typhi (NARST) was first isolated in Viet Nam in 1993. Analysis of the quinolone resistance-determining region of gyrA in 20 NARST isolates by polymerase chain reaction and single-stranded conformational polymorphism yielded two novel patterns: pattern II corresponding to a point mutation at nucleotide 87 Asp-->Gly (n = 17), and pattern III corresponding to a point mutation at nucleotide 83 Ser-->Phe (n = 3). In trials of short-course ofloxacin therapy for uncomplicated typhoid, 117 (78%) of 150 patients were infected with multidrug-resistant S. typhi, 18 (15%) of which were NARST. The median time to fever clearance was 156 hours (range, 30-366 hours) for patients infected with NARST and 84 hours (range, 12-378 hours) for those infected with nalidixic acid-susceptible strains (P < .001). Six (33.3%) of 18 NARST infections required retreatment, whereas 1 (0.8%) of 132 infections due to susceptible strains required retreatment (relative risk = 44; 95% confidence interval = 5.6-345; P < .0001). We recommend that short courses of quinolones not be used in patients infected with NARST

    Adiposity in relation to age as predictor of severity of sleep apnea in children with snoring

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    Correlation between obesity and obstructive sleep apnea has been documented in both adults and children. This investigation evaluated importance of body mass index (BMI) in relation to age as predictor of severity of obstructive sleep-disordered breathing (SDB). Children with habitual snoring referred for polysomnography were recruited. BMI Z score (>= 1.036 vs five vs 6 years). Two hundered eighty-four participants were recruited: 75 young children (4.6 +/- 1 years) with high BMI (1.9 +/- 0.7); 95 young subjects (4.5 +/- 1.1 years) with low BMI (-0.2 +/- 1.3); 55 older children (9.2 +/- 1.8 years) with high BMI (1.8 +/- 0.5); and 59 older participants (9.7 +/- 2.2 years) with low BMI (-0.2 +/- 1.1). Odds ratios for AHI > 5 in young/high BMI children, young/low BMI subjects, and older/high BMI subjects relative to older/low BMI participants were: 6.5 (95% confidence interval 2.1-19.9), 7.3 (2.4-22) and 2 (0.6-7.3), respectively. Large tonsil size was associated with young age (odds ratio 1.97; 1.2-3.3). Among children with habitual snoring, adiposity does not predict severity of obstructive SDB in early childhood probably due to the prominent role of adenotonsillar hypertrophy. However, it may have a more important contribution to severity of SDB in older children
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