Lamb Wave Scattering from Rivets

For structures with large surface areas, a full integrity evaluation can be a time-consuming operation. Lamb wave techniques allow this evaluation to be performed with waves propagating along one dimension of the inspection area while the probing transducers are moved in the perpendicular dimension, giving information about the presence of flaws within the entire scanned area. For riveted structures the scattering of the Lamb waves from the rivets is often the dominant feature in the measured response, masking the more subtle effects of Lamb wave interactions with the flaws of interest [1]. In this paper we consider the scattering of lowest mode symmetric and antisymmetric Lamb waves from model rivets, and derive analytic expressions for the scattered fields. With solutions of this type the disruptive effects of the rivets can be “processed out” of measured data in order to expose the signals which are due to the flaws in the structure

Fluvoxamine for aripiprazole-associated akathisia in patients with schizophrenia: a potential role of sigma-1 receptors

<p>Abstract</p> <p>Background</p> <p>Second-generation antipsychotic drugs have been reported to cause fewer incidences of extrapyramidal side effects (EPSs) than typical antipsychotic drugs, but adverse events such as akathisia have been observed even with atypical antipsychotic drugs. Although understanding of the pathophysiology of akathisia remains limited, it seems that a complex interplay of several neurotransmitter systems might play a role in its pathophysiology. The endoplasmic reticulum protein sigma-1 receptors are shown to regulate a number of neurotransmitter systems in the brain.</p> <p>Methods</p> <p>We report on two cases in which monotherapy of the selective serotonin reuptake inhibitor and sigma-1 receptor agonist fluvoxamine was effective in ameliorating the akathisia of patients with schizophrenia treated with the antipsychotic drug aripiprazole.</p> <p>Results</p> <p>The global score on the Barnes Akathisia Scale in the two patients with schizophrenia treated with aripiprazole decreased after fluvoxamine monotherapy.</p> <p>Conclusion</p> <p>Doctors may wish to consider fluvoxamine as an alternative approach in treating akathisia associated with antipsychotic drugs such as aripiprazole.</p

Hepatitis B Sero-Prevalence and Risk Behaviors Among Immigrant Men in a Population-Based Household Survey in Low-Income Neighborhoods of Northern California

Background Despite an effective vaccine, 60,000 new HBV infections were reported in the US in 2004; 95% in adults. We evaluate HBV sero-prevalence, risk behaviors and self-reported vaccination among Latino immigrant, Asian immigrant and US born low income men in five northern California counties. Methods Population based, cross sectional survey of HBV sero-prevalence and risk behaviors in men aged 18 to 35 years. Results Among 1,512 men screened, Asian immigrants were most likely to have had prior HBV infection (15.1%) and chronic infection (3.8%) compared to US born (prior 5.1%, chronic 0.6%) and Latino immigrant men (prior 2.0%, chronic 0.3%.) Reported HBV vaccination was lowest for Latino immigrants (12%) compared to Asian immigrants and US born men (35% in both.) Latino immigrants reported less educational attainment, medical insurance coverage and access to a physician in the last six months. Discussion Healthcare providers should routinely screen Asian immigrants for HBV regardless of their self reported vaccination status. Latino immigrants may comprise an important group of under-vaccinated, at risk persons in California. HBV testing and vaccination of immigrants soon after US arrival should be encouraged

Genome-wide enhancer maps link risk variants to disease genes

Genome-wide association studies (GWAS) have identified thousands of noncoding loci that are associated with human diseases and complextraits, each of which could reveal insights into the mechanisms of disease(1). Many ofthe underlying causal variants may affect enhancers(2,3), but we lack accurate maps of enhancers and their target genes to interpret such variants. We recently developed the activity-by-contact (ABC) model to predict which enhancers regulate which genes and validated the model using CRISPR perturbations in several cell types(4). Here we apply this ABC model to create enhancer-gene maps in 131 human cell types and tissues, and use these maps to interpret the functions of GWAS variants. Across 72 diseases and complex traits, ABC links 5,036 GWAS signals to 2,249 unique genes, including a class of 577genesthat appear to influence multiple phenotypes through variants in enhancers that act in different cell types. In inflammatory bowel disease (IBD), causal variants are enriched in predicted enhancers by more than 20-fold in particular cell types such as dendritic cells, and ABC achieves higher precision than other regulatory methods at connecting noncoding variants to target genes. These variant-to-function maps reveal an enhancer that contains an IBD risk variant and that regulates the expression of PPIF to alter the membrane potential of mitochondria in macrophages. Our study reveals principles of genome regulation, identifies genes that affect IBD and provides a resource and generalizable strategy to connect risk variants of common diseases to their molecular and cellular functions.Peer reviewe

Application of Equilibrium Models of Solution Hybridization to Microarray Design and Analysis

Background: The probe percent bound value, calculated using multi-state equilibrium models of solution hybridization, is shown to be useful in understanding the hybridization behavior of microarray probes having 50 nucleotides, with and without mismatches. These longer oligonucleotides are in widespread use on microarrays, but there are few controlled studies of their interactions with mismatched targets compared to 25-mer based platforms. Principal Findings: 50-mer oligonucleotides with centrally placed single, double and triple mismatches were spotted on an array. Over a range of target concentrations it was possible to discriminate binding to perfect matches and mismatches, and the type of mismatch could be predicted accurately in the concentration midrange (100 pM to 200 pM) using solution hybridization modeling methods. These results have implications for microarray design, optimization and analysis methods. Conclusions: Our results highlight the importance of incorporating biophysical factors in both the design and the analysis of microarrays. Use of the probe ‘‘percent bound’ ’ value predicted by equilibrium models of hybridization is confirmed to be important for predicting and interpreting the behavior of long oligonucleotide arrays, as has been shown for shor

The instantaneous helical axis of the subtalar and talocrural joints: a non-invasive in vivo dynamic study

<p>Abstract</p> <p>Background</p> <p>An understanding of rear-foot (talocrural and subtalar joints) kinematics is critical for diagnosing foot pathologies, designing total ankle implants, treating rear-foot injuries and quantifying gait abnormalities. The majority of kinematic data available have been acquired through static cadaver work or passive <it>in vivo </it>studies. The applicability of these data to dynamic <it>in vivo </it>situations remains unknown. Thus, the purpose of this study was to fully quantify subtalar, talocrural and calcaneal-tibial <it>in vivo </it>kinematics in terms of the instantaneous helical axis (IHA) in twenty-five healthy ankles during a volitional activity that simulated single-leg toe-raises with partial-weight support, requiring active muscle control.</p> <p>Methods</p> <p>Subjects were each placed supine in a 1.5 T MRI and asked to repeat this simulated toe-raise while a full sagittal-cine-phase contrast (dynamic) MRI dataset was acquired. From the cine-phase contrast velocity a full kinematic description for each joint was derived.</p> <p>Results</p> <p>Nearly all motion quantified at the calcaneal-tibial joint was attributable to the talocrural joint. The subtalar IHA orientation and position were highly variable; whereas, the talocrural IHA orientation and position were extremely consistent.</p> <p>Conclusion</p> <p>The talocrural was well described by the IHA and could be modeled as a fixed-hinge joint, whereas the subtalar could not be.</p