644 research outputs found

    Magnetic tension and gravitational collapse

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    The gravitational collapse of a magnetised medium is investigated by studying qualitatively the convergence of a timelike family of non-geodesic worldlines in the presence of a magnetic field. Focusing on the field's tension we illustrate how the winding of the magnetic forcelines due to the fluid's rotation assists the collapse, while shear-like distortions in the distribution of the field's gradients resist contraction. We also show that the relativistic coupling between magnetism and geometry, together with the tension properties of the field, lead to a magneto-curvature stress that opposes the collapse. This tension stress grows stronger with increasing curvature distortion, which means that it could potentially dominate over the gravitational pull of the matter. If this happens, a converging family of non-geodesic lines can be prevented from focusing without violating the standard energy conditions.Comment: Typos corrected. Published versio

    Survey of Valinokkam Bay and adjoining area to assess its suitability for integrated sea farming — A report

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    The Valinokkam Bay and the adjoining area, east of the Bay surveyed, lie between Lat. 9°9' N and 9° 12' N and Long. 78°30'E and 78°42'E . The available information indicates that the bay and the adjoining grounds in the sea are highly productive and suitable for sea farming activities

    Novel mutations in human and mouse SCN4A implicate AMPK in myotonia and periodic paralysis

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    Mutations in the skeletal muscle channel (SCN4A), encoding the Nav1.4 voltage-gated sodium channel, are causative of a variety of muscle channelopathies, including non-dystrophic myotonias and periodic paralysis. The effects of many of these mutations on channel function have been characterized both in vitro and in vivo. However, little is known about the consequences of SCN4A mutations downstream from their impact on the electrophysiology of the Nav1.4 channel. Here we report the discovery of a novel SCN4A mutation (c.1762A>G; p.I588V) in a patient with myotonia and periodic paralysis, located within the S1 segment of the second domain of the Nav1.4 channel. Using N-ethyl-N-nitrosourea mutagenesis, we generated and characterized a mouse model (named draggen), carrying the equivalent point mutation (c.1744A>G; p.I582V) to that found in the patient with periodic paralysis and myotonia. Draggen mice have myotonia and suffer from intermittent hind-limb immobility attacks. In-depth characterization of draggen mice uncovered novel systemic metabolic abnormalities in Scn4a mouse models and provided novel insights into disease mechanisms. We discovered metabolic alterations leading to lean mice, as well as abnormal AMP-activated protein kinase activation, which were associated with the immobility attacks and may provide a novel potential therapeutic target

    Ion-Sensitive Field-Effect Transistors With Micropillared Gates for Measuring Cell Ion Exchange at Molecular Levels

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    The detection of small concentrations of cancer cells before cancer takes over the primary organ completely, or metastasizes to other areas of the body is important for early screening of cancer. One approach to address cancer early screening is through cell ion exchange bioelectricity, which characterizes voltage potential in non-neuronal cells to regulate shape changing, proliferation, differentiation, migration, and cancer formation. Herein, novel ion-sensitive field-effective transistor (ISFET) modality is shown to measure cell behavior during the change of cell properties at molecular levels. ISFETs produce low resistance signals and consume low power. The small size of ISFETs enables miniature diagnosis devices that can be affordably fabricated in a massive array format. A large number of cells can be measured in parallel. Therefore, ISFET allows the combination of low sample requirements and prompt response. ISFETs have the ability to measure the effect of ions from complex biological samples and can be used as affordable point of care devices

    If current inhibitor ivabradine in patients with idiopathic dilated cardiomyopathy: Impact on the exercise tolerance and quality of life

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    Background: Evidence supported a beneficial effect of ivabradine on clinical outcome of patients with systolic heart failure, and a sinus heart rate (HR) ≥ 70 bpm. We explored the effect of ivabradine, vs. placebo, added to evidence-based treatment on exercise tolerance and quality of life in patients with idiopathic dilated cardiomyopathy. Methods: We enrolled 43 consecutive patients with dilated cardiomyopathy of no apparent cause, a left ventricular ejection fraction (LVEF) < 40%, New York Heart Association class ≥ II, sinus HR ≥ 70 bpm, and background evidence-based anti-failure medications. Ischemic heart disease was ruled out. Patients were randomized (1:1) to receive ivabradine or placebo. Ivabradine was titrated up gradually till 7.5 mg twice daily, or a HR < 60 bpm, and continued for 3 months. Symptom-limited exercise tolerance test was performed, and quality of life was assessed by the Minnesota Living With Heart Failure Questionnaire at 0, and 3 months. Results: Forty-three patients were randomized to ivabradine (n = 20), or placebo (n = 23). Mean age was 50.8 ± 14.5 years (53.5% males). Mean HR was 85 ± 12 bpm, and mean LVEF was 32 ± 6%. Mean dose of carvedilol was 31.2% of the target dose. Baseline HR, blood pressure, exercise tolerance, Minnesota questionnaire score, and left ventricular systolic function were comparable between the two groups (p > 0.05 for all). At 3 months, mean dose of ivabradine was 6.8 mg bid. Ivabradine-treated patients had a lower HR, and improved left ventricular dimensions and systolic function, versus placebo-treated ones (p < 0.05 for all). HR dropped by a mean of 14 bpm in the ivabradine group, corrected for placebo. Both exercise tolerance, and Minnesota questionnaire score were better in the ivabradine group (p < 0.05 both). Ivabradine was well-tolerated. Conclusions: In symptomatic patients with idiopathic dilated cardiomyopathy, the addition of ivabradine, vs. placebo, to evidence-based treatment, reduced HR, and improved functional capacity, at short-term follow-up

    Ecology of Aquatic Plant Myriophyllum spicatum L. New record to Kurdistan, Erbil, Iraq

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    This work deals with the study of aquatic plant Eurasian watermilfoil, Myriophyllum spicatum L. new record to Kurdistan, It is submersed aquatic weed that can easily become excessive in growth and maybe a completely choked small shallow pond. The ecological habitats, distribution, growth characteristic, species description, taxonomical status, economically important and other information, including their control in the aquatic ecosystem, are given in the text. In Kurdistan this plant found in several small and shallow ponds, at the edge of the Greater Zab River behind Kapran village near Gwer sub-district, this area is free from ecological and biological studies.  Ecologically the waters are natural, hard, alkaline, rich in nutrients and Cl-1 ions. And contain a certain amount of heavy metal such as (Mg+², Zn+², Cu+², Fe+², Cr+², Cd) but lead (Pb) was not detected

    THE PREVALENCE OF MALOCCLUSION AND ORTHODONTIC TREATMENT NEED IN A SAMPLE OF SYRIAN CHILDREN

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    Knowledge of a population’s epidemiological situation is vital in planning and provision of dental health services. The present study was undertaken to determine the prevalence of malocclusion and orthodontic treatment need in Syrian children. A randomly selected sample of 200 Syrian children aged between 8 and 13 years was collected from three different public schools in Damascus. For each participant, the records were a pair of dental study casts and a frontal intra-oral photograph. Firstly, Angle’s classification was used to classify malocclusion and the treatment need was assessed utilizing the Aesthetic Component (AC) and the Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN). The treatment demand was also evaluated in association with gender and the connection between the two components of IOTN was statistically ascertained. The results of the study showed that more than one third of the subjects in the sample were in moderate to great need for orthodontic treatment. No significant difference in treatment need was found between genders and a statistically significant association was expressed between the two components of IOTN
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