Exploiting the Symmetry of the Resonator Mode to Enhance PELDOR Sensitivity.

Pulsed electron paramagnetic resonance (EPR) spectroscopy using microwaves at two frequencies can be employed to measure distances between pairs of paramagnets separated by up to 10 nm. The method, combined with site-directed mutagenesis, has become increasingly popular in structural biology for both its selectivity and capability of providing information not accessible through more standard methods such as nuclear magnetic resonance and X-ray crystallography. Despite these advantages, EPR distance measurements suffer from poor sensitivity. One contributing factor is technical: since 65 MHz typically separates the pump and detection frequencies, they cannot both be located at the center of the pseudo-Lorentzian microwave resonance of a single-mode resonator. To maximize the inversion efficiency, the pump pulse is usually placed at the center of the resonance, while the observer frequency is placed in the wing, with consequent reduction in sensitivity. Here, we consider an alternative configuration: by spacing pump and observer frequencies symmetrically with respect to the microwave resonance and by increasing the quality factor, valuable improvement in the signal-to-noise ratio can be obtained

Gene panel analysis for nonsyndromic cryptogenic neonatal/infantile epileptic encephalopathy

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A diagrammatic approach to search for minimum sampling frequency and quantization resolution for digital control of power converters

A diagrammatic approach to find out the minimum sampling frequency and quantization resolution for digital control of power converters is proposed. The proposed solution algorithm combines consideration on both time sampling and quantization resolution axes to search for the minimum required digital controller settings. Experiments results are presented to justify the proposed algorithm. © 2007 IEEE.published_or_final_versio

Analysis of mutations in 7 genes associated with neuronal excitability and synaptic transmission in a cohort of children with non-syndromic Infantile Epileptic Encephalopathy

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Identification of SCN1A and PCDH19 mutations in Chinese children with Dravet syndrome

Background: Dravet syndrome is a severe form of epilepsy. Majority of patients have a mutation in SCN1A gene, which encodes a voltage-gated sodium channel. A recent study has demonstrated that 16% of SCN1A-negative patients have a mutation in PCDH19, the gene encoding protocadherin-19. Mutations in other genes account for only a very small proportion of families. TSPYL4 is a novel candidate gene within the locus 6q16.3-q22.31 identified by linkage study. Objective: The present study examined the mutations in epileptic Chinese children with emphasis on Dravet syndrome. Methods: A hundred children with severe epilepsy were divided into Dravet syndrome and non-Dravet syndrome groups and screened for SCN1A mutations by direct sequencing. SCN1A-negative Dravet syndrome patients and patients with phenotypes resembling Dravet syndrome were checked for PCDH19 and TSPYL4 mutations. Results: Eighteen patients (9 males, 9 females) were diagnosed to have Dravet syndrome. Among them, 83% (15/18) had SCN1A mutations including truncating (7), splice site (2) and missense mutations (6). The truncating/splice site mutations were associated with moderate to severe degree of intellectual disability (p<0.05). During the progression of disease, 73% (11/15) had features fitting into the diagnostic criteria of autism spectrum disorder and 53% (8/15) had history of vaccination-induced seizures. A novel PCDH19 p.D377N mutation was identified in one SCN1A-negative female patient with Dravet syndrome and a known PCDH19 p.N340S mutation in a female non-Dravet syndrome patient. The former also inherited a TSPYL4 p.G60R variant. Conclusion: A high percentage of SCN1A mutations was identified in our Chinese cohort of Dravet syndrome patients but none in the rest of patients. We demonstrated that truncating/splice site mutations were linked to moderate to severe intellectual disability in these patients. A de novo PCDH19 missense mutation together with an inherited TSPYL4 missense variant were identified in a patient with Dravet syndrome. © 2012 Kwong et al.published_or_final_versio

Entanglement transformation between sets of bipartite pure quantum states using local operations

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Ginkgo biloba extract (EGb761) inhibits mitochondria-dependent caspase pathway and prevents apoptosis in hypoxia-reoxygenated cardiomyocytes

Background: EGb761 is a standard extract from the leaves of Ginkgo biloba (Yinxing) containing ginkgo-flavone glycosides and terpenoid. The flavonoid components of EGb761 scavenge free radicals and protect myocardia from ischemia-reperfusion injury. The present study aims to determine the effects of the active compounds of EGb761 on mitochondria-dependent caspase pathway.Methods: Cardiomyocytes were exposed to 24 hours of hypoxia and four hours of reoxygenation, and pretreated with EGb761, bilobalide and quertcetin. By using immunoblot, immunofluorescent, biochemical and flow cytometry techniques, we compared the effects of EGb761 and its representative constituents including quercetin and bilobalides on regulating mitochondria-dependent caspases signal pathway and apoptotic cell death in the hypoxia-reoxygenated cardiomyocytes.Results: Pretreatment with EGb761 significantly inhibited the release of cytochrome c from mitochondria, the expression of caspase-3, cleavage activities of caspases and attenuated apoptotic cell death. The effects of quercetin on the release of cytochrome c, the cleavage activities of caspases and cell death were similar to those of EGb761 but better than those of bilobalide.Conclusion: The antioxidant constituents of EGb761 such as quercetin contribute to the cardioprotective effects of EGb761 and inhibit the mitochondria-dependent caspase pathway. It is possible that the mitochondria-dependent caspase pathway may be one of the molecular targets of EGb761 against myocardial ischemia-reperfusion injury. © 2011 Shen et al; licensee BioMed Central Ltd.published_or_final_versio

Hepatic cancer stem cell marker granulin-epithelin precursor and β-catenin expression associate with recurrence in hepatocellular carcinoma

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Anti-NMDA-R encephalitis: an encephalitis lerthargica-like illness

Posters: no. P14A girl of 3 years and 9 months with a 3-day history of fever and upper respiratory tract infection (URTI) was admitted with a generalised tonic-clonic convulsion, and delirium with screaming, non-sense talking, and agitation. For the first week after admission, she was lethargic with fluctuating awareness and mutism during the day but poor sleep at night. Workup for acute encephalopathy including autoimmune, infective, toxicology, metabolic and vasculitic screening showed negative findings. Erythrocyte sedimentation rate was markedly elevated and ...published_or_final_versionThe 1st Hong Kong Neurological Congress cum 22nd Annual Scientific Meeting of the Hong Kong Neurological Society, Hong Kong, 6-8 November 2009. In Hong Kong Medical Journal, 2009, v. 15 n. 6, suppl. 7, p. 47, abstract P1

Fluctuating Hemiparesis Secondary to Moyamoya Phenomenon in a Child with Down Syndrome: a case report

Moyamoya phenomenon is a term used to describe extensive collateralization of the circle of Willis arteries associated with severe unilateral or bilateral internal carotid artery stenosis or occlusion in the presence of certain conditions. Down syndrome is among these conditions. A case is reported of a young girl with Down syndrome who presented with fluctuating right-sided weakness and facial droop found to have cerebral ischemia. Subsequent investigations disclosed characteristic "puff of smoke" patterns on angiographic studies consistent with moyamoya phenomenon. The patient was initially treated with aspirin and eventually underwent an encephalomyosynangiosis. This young patient with Down syndrome and moyamoya phenomenon serves as a reminder of the association between these two conditions