621 research outputs found

    Arrested States formed on Quenching Spin Chains with Competing Interactions and Conserved Dynamics

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    We study the effects of rapidly cooling to T = 0 a spin chain with conserved dynamics and competing interactions. Depending on the degree of competition, the system is found to get arrested in different kinds of metastable states. The most interesting of these has an inhomogeneous mixture of interspersed active and quiescent regions. In this state, the steady-state autocorrelation function decays as a stretched exponential exp((t/τo)13)\sim \exp(-{(t/\tau_{o})}^{{1}\over{3}}), and there is a two-step relaxation to equilibrium when the temperature is raised slightly.Comment: 4 pages, Latex, 3 postscript figures. Phys. Rev. E to appear (1999

    Measurement of strain evolution in overloaded roller bearings using time-of-flight neutron diffraction

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    Neutron diffraction is an established method for non-destructively characterising residual stress or observing in situ strain during external stimuli. Neutron based stroboscopic techniques have previously been introduced for measuring strains undergoing cyclic processes but have not been used for tribological applications. This work presents a novel approach for measuring the evolution of radial strain in a rotating bearing through part of the component's lifetime. A cylindrical roller bearing was pre-overloaded to increase the probability of damage within a reasonable experimental time and to help develop further understanding of the influence such events have on bearing life, notably for the application of wind turbine gearbox bearing failure. The stroboscopic neutron diffraction technique was successful in measuring time-resolved contact strain, with a significant increase in compressive radial strain being observed after a suspected failure had been detected using condition monitoring techniques, implemented for validating damage propagation. Cyclic contact strains associated with rolling contact fatigue were also evaluated using neutron diffraction

    Respiratory parameters for the classification of dysfunctional insulin secretion in pancreatic islets

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    The development of obesity and type 2 diabetes (T2D) has been associated with impaired mitochondrial function. In pancreatic beta (β) cells, mitochondrial energy metabolism plays a central role in triggering and controlling glucose-stimulated insulin secretion (GSIS). Here, we have explored whether mitochondrial bioenergetic parameters assessed with Seahorse extracellular flux technology can quantitatively predict insulin secretion. We metabolically stressed male C57BL/6 mice by high-fat feeding (HFD) and measured the glucose sensitivity of islet respiration and insulin secretion. The diet-induced obese (DIO) mice developed hyperinsulinemia, but no pathological secretory differences were apparent between isolated DIO and chow islets. Real-time extracellular flux analysis, however, revealed a lower respiratory sensitivity to glucose in DIO islets. Correlation of insulin secretion with respiratory parameters uncovers compromised insulin secretion in DIO islets by oxidative power. Normalization to increased insulin contents during DIO improves the quantitative relation between GSIS and respiration, allowing to classify dysfunctional properties of pancreatic insulin secretion, and thereby serving as valuable biomarker for pancreatic islet glucose responsiveness and health

    RESEARCH ON FORMULATION AND EVALUATION OF INSITU MUCOADHESIVE NASAL GELS OF METOCLOPRAMIDE HYDROCHLORIDE

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    ABSTRACT The prolonged residence of drug formulation in the nasal cavity is of utmost importance for intranasal drug delivery. The objective of the present investigation was to develop a mucoadhesive in situ gel with reduced nasal mucocilliary clearance in order to improve the bioavailability of the antiemetic drug, Metoclopramide Hydrochloride. The in situ gelation upon contact with nasal mucosa was conferred via the use of the thermogelling Methyl cellulose whereas mucoadhesion and drug release enhancement were modulated via the use of sodium alginate and polyethylene glycol polymers respectively. The results revealed that the mucoadhesive polymer increased the gel viscosity but reduced its sol gel transition temperatures and the drug release. The inclusion of polyethylene glycol polymer counteracted the effect of mucoadhesive polymer where by it decreased the gel consistency and increased the sol gel transition as well as in vitro drug diffusion. The in vitro tests performed for mucoadhesive strength and drug diffusion showed that nasal in situ gelling formulations prepared are having good mucoadhesive strength with nearly100percente drug diffusion within four hours. So this study points to the potential of mucoadhesive in situ nasal gel in terms of ease of administration, accuracy of dosing, prolonged nasal residence and improved nasal bioavailability.  Keywords: Nasal Gel, Metoclopramide Hydrochloride, Methyl Cellulose, Mucocilliary Clearance

    Two measures of systemic inflammation are positively associated with haemoglobin levels in adolescent girls living in rural India: A cross‐sectional study

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    ObjectiveThis study tested the hypothesis that systemic inflammation is inversely associated with haemoglobin levels in adolescent girls in India.MethodsThe study population consisted of adolescent girls aged between 10 and 19 years living in a remote rural region in Maharashtra State, India. Data were collected on anthropometric measures, and a venous blood sample taken and tested for Complete Blood Count and C‐reactive Protein (CRP).ResultsOf 679 individuals who were invited to the research site to participate, data were available from 401 participants giving a response rate of 59%. Median blood CRP was 1.26 mg/L (Range 0.00 to 26.33), and 167 (41.6%) participants had CRP level [less than] 1.0 mg/L. The mean haemoglobin was 12.24 g/dL (Standard deviation [SD] 1.51), and the mean total White Blood Cells (WBC) count was 9.02 x103/μL (SD 2.00). With each g/dL increase in blood haemoglobin, the risk of having an elevated CRP of ≥1 mg/L increased with an odds ratio of 1.16 (95% CI 1.01 to 1.33, p=0.03). Total WBC count was also positively associated with blood haemoglobin, increasing by 0.24 x103/μL (95% CI 0.11 to 0.37, p [less than] 0.001) per g/dL increase in haemoglobin. Both analyses were adjusted for age. ConclusionsIn this population, blood haemoglobin levels were positively associated with two measures of systemic inflammation, contrary to the primary hypothesis being tested. Other unmeasured environmental exposures may modify haemoglobin levels in this population. Understanding this observation may help design better public health interventions to improve the wellbeing of adolescent girls in India

    Direct Substrate Delivery into Mitochondrial-Fission Deficient Pancreatic Islets Rescues Insulin Secretion

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    In pancreatic beta cells, mitochondrial bioenergetics control glucose-stimulated insulin secretion (GSIS). Mitochondrial dynamics are generally associated with quality control, maintaining the functionality of bioenergetics. By acute pharmacological inhibition of mitochondrial fission protein Drp1, we here demonstrate that mitochondrial fission is necessary for GSIS in mouse and human islets. We confirm that genetic silencing of Drp1 increases mitochondrial proton leak in MIN6 cells. However, our comprehensive analysis of pancreatic islet bioenergetics reveals that Drp1 does not control insulin secretion via its effect on proton leak but instead via modulation of glucose-fuelled respiration. Notably, pyruvate fully rescues the impaired insulin secretion of fission-deficient beta cells, demonstrating that defective mitochondrial dynamics solely impact substrate supply upstream of oxidative phosphorylation. The present findings provide novel insights in how mitochondrial dysfunction may cause pancreatic beta cell failure. In addition, the results will stimulate new thinking in the intersecting fields of mitochondrial dynamics and bioenergetics, as treatment of defective dynamics in mitochondrial diseases appears to be possible by improving metabolism upstream of mitochondria

    Respiratory viral infections detected by multiplex PCR among pediatric patients with lower respiratory tract infections seen at an urban hospital in Delhi from 2005 to 2007

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    <p>Abstract</p> <p>Background</p> <p>Acute lower respiratory tract infections (ALRI) are the major cause of morbidity and mortality in young children worldwide. Information on viral etiology in ALRI from India is limited. The aim of the present study was to develop a simple, sensitive, specific and cost effective multiplex PCR (mPCR) assay without post PCR hybridization or nested PCR steps for the detection of respiratory syncytial virus (RSV), influenza viruses, parainfluenza viruses (PIV1–3) and human metapneumovirus (hMPV). Nasopharyngeal aspirates (NPAs) were collected from children with ALRI ≤ 5 years of age. The sensitivity and specificity of mPCR was compared to virus isolation by centrifugation enhanced culture (CEC) followed by indirect immunofluorescence (IIF).</p> <p>Results</p> <p>From April 2005–March 2007, 301 NPAs were collected from children attending the outpatient department or admitted to the ward of All India Institute of Medical Sciences hospital at New Delhi, India. Multiplex PCR detected respiratory viruses in 106 (35.2%) of 301 samples with 130 viruses of which RSV was detected in 61, PIV3 in 22, PIV2 in 17, hMPV in 11, PIV1 in 10 and influenza A in 9 children. CEC-IIF detected 79 viruses only. The sensitivity of mPCR was 0.1TCID<sub>50 </sub>for RSV and influenza A and 1TCID<sub>50 </sub>for hMPV, PIV1, PIV2, PIV3 and Influenza B. Mixed infections were detected in 18.8% of the children with viral infections, none detected by CEC-IIF. Bronchiolitis was significantly associated with both total viral infections and RSV infection (p < 0.05). History of ARI in family predisposed children to acquire viral infection (p > 0.05).</p> <p>Conclusion</p> <p>Multiplex PCR offers a rapid, sensitive and reasonably priced diagnostic method for common respiratory viruses.</p

    Cystic fibrosis presenting as recurrent pancreatitis in a young child with a normal sweat test and pancreas divisum: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Pancreatitis is a rare manifestation of cystic fibrosis (CF) and may rarely be the presenting symptom in adolescent or adult patients with CF. We report a case of a 4 year-old female who initially presented with recurrent pancreatitis, a normal sweat test, and a diagnosis of pancreas divisum. She was subsequently diagnosed with cystic fibrosis at the age of 6 years, despite normal growth and no pulmonary symptoms, after nasal potential difference measurements suggested possible CF and two known CF-causing mutations (ΔF508 and L997F) were detected.</p> <p>Case Presentation</p> <p>An otherwise healthy 4 year-old female developed chronic pancreatitis and was diagnosed with pancreas divisum. Sphincterotomy was performed without resolution of her pancreatitis. Sweat test was negative for cystic fibrosis, but measurement of nasal potential differences suggested possible cystic fibrosis. These results prompted extended Cystic Fibrosis Transmembrane Regulator Conductance (CFTR) mutational analysis that revealed a compound heterozygous mutation: ΔF508 and L997F.</p> <p>Conclusion</p> <p>CFTR mutations should be considered in cases of chronic or recurrent pancreatitis despite a negative sweat test and the presence of pancreas divisum. Children with CFTR mutations may present with recurrent pancreatitis, lacking any other signs or symptoms of cystic fibrosis. It is possible that the combination of pancreas divisum and abnormal CFTR function may contribute to the severity and frequency of recurrent pancreatitis.</p
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