988 research outputs found

    Sound transmission across a rectangular duct section with a thin micro-perforated wall backed by a sidebranch cavity

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    An experimental investigation was carried out in the present study for deeper understanding on the sound transmission across a rectangular duct section installed with a thin micro-perforated panel (as a duct wall) backed by a sidebranch cavity. The contributions of the panel configuration and the cavity depth on reducing sound transmission are examined in detail. Results indicate a complicated relationship between sound power transmission, micro-perforation configuration and backing cavity depth. For panels with strong sound absorption capacity, sound power transmission efficiency is reduced as the panels become less absorptive, but there exists a frequency or frequency band above which the opposite is observed. It appears that there is also a certain level of panel sound absorption below which the sound transmission is strengthened over the whole frequency range of present study when the panel becomes less absorptive to sound

    Sympathetic nervous system activity and anti-lipolytic response to iv-glucose load in subcutaneous adipose tissue of obese and obese type 2 diabetic subjects

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    The study aim was to investigate the effect of endogenous insulin release on lipolysis in subcutaneous adipose tissue after adrenergic stimulation in obese subjects diagnosed with type 2 diabetes (T2D). In 14 obese female T2D subjects, or 14 obese non-T2D controls, glycerol concentration was measured in response to the α1,2,ß-agonist norepinephrine, the α1-agonist norfenefrine and the ß2-agonist terbutaline (each 10-4 M), using the microdialysis technique. After 60 minutes of stimulation, an intravenous glucose load (0.5 g/kg lean body mass) was given. Local blood flow was monitored by means of the ethanol technique. Norepinephrine and norfenefrine induced a four and three fold rise in glycerol dialysate concentration (p\u3c0.001, each), with a similar pattern in adipose tissue. Following agonist stimulation and glucose infusion, endogenous insulin release inhibited lipolysis in the presence of norepinephrine, which was more rapid and pronounced in healthy obese controls than in T2D subjects (p = 0.024 obese vs T2D subjects). Insulin-induced inhibition of lipolysis in the presence of norfenefrine was similar in all study participants. In the presence of terbutaline the lipolysis rate increased two fold until the effect of endogenous insulin (p\u3c0.001). A similar insulin-induced decrease in lipolysis was observed for each of the norfenefrine groups and the terbutaline groups, respectively. Adipose tissue blood flow remained unchanged after the iv-glucose load. Both norepinephrine and norfenefrine diminished blood flow slightly, but insulin reversed this response (p\u3c0.001 over the entire time). Terbutaline alone and terbutaline plus increased endogenous insulin augmented local blood flow (p\u3c0.001 over the entire time). In conclusion, a difference in insulin-induced inhibition of lipolysis was observed in obese T2D subjects compared to obese healthy controls following modulation of sympathetic nervous system activity and is assumed to be due to ß1-adrenoceptor mediated stimulation by norepinephrine

    A large population-based investigation into the genetics of susceptibility to gastrointestinal infections and the link between gastrointestinal infections and mental illness.

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    Gastrointestinal infections can be life threatening, but not much is known about the host's genetic contribution to susceptibility to gastrointestinal infections or the latter's association with psychiatric disorders. We utilized iPSYCH, a genotyped population-based sample of individuals born between 1981 and 2005 comprising 65,534 unrelated Danish individuals (45,889 diagnosed with mental disorders and 19,645 controls from a random population sample) in which all individuals were linked utilizing nationwide population-based registers to estimate the genetic contribution to susceptibility to gastrointestinal infections, identify genetic variants associated with gastrointestinal infections, and examine the link between gastrointestinal infections and psychiatric and neurodevelopmental disorders. The SNP heritability of susceptibility to gastrointestinal infections ranged from 3.7% to 6.4% on the liability scale. Significant correlations were found between gastrointestinal infections and the combined group of mental disorders (OR = 2.09; 95% CI: 1.82-2.4, P = 1.87 × 10-25). Correlations with autism spectrum disorder, attention deficit hyperactivity disorder, and depression were also significant. We identified a genome-wide significant locus associated with susceptibility to gastrointestinal infections (OR = 1.13; 95% CI: 1.08-1.18, P = 2.9 × 10-8), where the top SNP was an eQTL for the ABO gene. The risk allele was associated with reduced ABO expression, providing, for the first time, genetic evidence to support previous studies linking the O blood group to gastrointestinal infections. This study also highlights the importance of integrative work in genetics, psychiatry, infection, and epidemiology on the road to translational medicine

    How cat-behavior advisors can improve clients’ willingness to adopt their advice: an investigation of advice severity, advisor credibility, and clients’ self-identity

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    Feline behavioral problems can be treated successfully by good advice from cat-behavior advisors, but guardians often do not comply with their advice. An experimental survey under 703 cat guardians was used to investigate what advisors can do to increase their clients’ compliance with environmental enrichment advice. By systematically varying the credibility of the advisor and the severity of their advice, the hypothesis was confirmed that highly credible advisors elicit more positive attitudes and compliance intentions than less credible advisors. Also as expected, mild advice resulted in stronger compliance intentions than severe advice because guardians believed they were better able to incorporate the required actions. Finally, guardians who more strongly thought of themselves as cat guardians were more likely to adopt the advice because they believed that other cat guardians would do the same. The investigation of factors that can increase cat guardians’ compliance with advisors’ recommendations for the treatment of behavioral problems is crucial because the wellbeing of domestic cats lies in the hands of their guardians. Several practical recommendations for cat-behavior advisors are offered.Social decision makin

    Hypomethylation of FAM63B in bipolar disorder patients

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    Bipolar disorder (BD) and schizophrenia (SZ) are known to share common genetic and psychosocial risk factors. A recent epigenome-wide association study performed on blood samples from SZ patients found significant hypomethylation of FAM63B in exon 9. Here, we used iPLEX-based methylation analysis to investigate two CpG sites in FAM63B in blood samples from 459 BD cases and 268 controls. Both sites were significantly hypomethylated in BD cases (lowest p value = 3.94 × 10−8). The methylation levels at the two sites were correlated, and no strong correlation was found with nearby single nucleotide polymorphisms (SNPs), suggesting that methylation differences at these sites are not readably picked up by genome-wide association studies. Overall, FAM63B hypomethylation was found in BD patients, thus replicating the initial finding in SZ patients. This study suggests that FAM63B is a shared epigenetic risk gene for the two disorders

    Risk of schizophrenia in relation to parental origin and genome-wide divergence

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    Background. Second-generation immigrants have an increased risk of schizophrenia, a finding that still lacks a satisfactory explanation. Various operational definitions of second-generation immigrants have been used, including foreign parental country of birth. However, with increasing global migration, it is not clear that parental country of birth necessarily is informative with regard to ethnicity. We compare two independently collected measures of parental foreign ethnicity, parental foreign country of birth versus genetic divergence, based on genome-wide genotypic data, to access which measure most efficiently captures the increased risk of schizophrenia among second-generation immigrants residing in Denmark. Method. A case-control study covering all children born in Denmark since 1981 included 892 cases of schizophrenia and 883 matched controls. Genetic divergence was assessed using principal component analyses of the genotypic data. Independently, parental foreign country of birth was assessed using information recorded prospectively in the Danish Civil Registration System. We compared incidence rate ratios of schizophrenia associated with these two independently collected measures of parental foreign ethnicity. Results. People with foreign-born parents had a significantly increased risk of schizophrenia [relative risk (RR) 1.94 (95% confidence intervals (CI) 1.41-2.65)]. Genetically divergent persons also had a significant increased risk [RR 2.43 ( 95% CI 1.55-3.82)]. Mutual adjustment of parental foreign country of birth and genetic divergence showed no difference between these measures with regard to their potential impact on the results. Conclusions. In terms of RR of schizophrenia, genetic divergence and parental foreign country of birth are interchangeable entities, and both entities have validity with regard to identifying second-generation immigrants
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