57 research outputs found
The Central Correlations of Hypercharge, Isospin, Colour and Chirality in the Standard Model
The correlation of the fractionally represented hypercharge group with the
isospin and colour group in the standard model determines as faithfully
represented internal group the quotient group
{\U(1)\x\SU(2)\x\SU(3)\over\Z_2\x\Z_3}. The discrete cyclic central
abelian-nonabelian internal correlation involved is considered with respect to
its consequences for the representations by the standard model fields, the
electroweak mixing angle and the symmetry breakdown. There exists a further
discrete -correlation between chirality and Lorentz properties and also a
continuous \U(1)-external-internal one between hyperisospin and chirality.Comment: 18 pages, latex, macros include
Explanation at the opioid receptor level for differing toxicity of morphine and morphine 6-glucuronide.
The radiolabelled opioid receptor binding affinities of morphine and its active metabolite morphine 6-glucuronide at the total mu, mu 1, mu 2 and delta receptors were determined. Morphine 6-glucuronide was found to have a 4-fold lower affinity for the mu 2 receptor (IC50 17 nM and 82 nM for morphine and morphine 6-glucuronide respectively, P = 0.01), the receptor postulated to be responsible for mediating the respiratory depression and gastrointestinal effects after morphine. This provides a possible explanation for the reduced respiratory depression and vomiting seen following morphine 6-glucuronide in man. A similar reduction in affinity of morphine 6-glucuronide was seen at the total mu receptor whilst there was no significant difference seen at the mu 1 or delta receptor. Hence the increased analgesic potency of morphine 6-glucuronide over morphine remains unexplained
A Note on Charge Quantization Through Anomaly Cancellation
In a minimal extension of the Standard Model, in which new neutral fermions
have been introduced, we show that the requirement of vanishing anomalies fixes
the hypercharges of all fermions uniquely. This naturally leads to electric
charge quantization in this minimal scenario which has features similar to the
Standard Model: invariance under the gauge group ,
conservation of the total lepton number and masslessness for the ordinary
neutrinos. Such minimal models might arise as low-energy realizations of some
heterotic superstring models or grand unified theories.Comment: 14p., TeX, (final version
Posttraumatic Stress Disorder Symptoms and Incarceration: The Impact on Sexual Risk-Taking, Sexually Transmitted Infections, and Depression Among Black Sexual Minority Men in HIV Prevention Trials Network (HPTN) 061
Black men and people belonging to sexual minority groups are disproportionately impacted by criminal legal involvement and sexually transmitted infections (STIs). Traumatic experiences are often associated with later criminal legal involvement, depression symptoms, sexual risk behavior, and STIs. Research on the joint influence of trauma and incarceration on STI risk among racial and/or sexual minority people is limited. This study tested the association between post-traumatic stress disorder (PTSD) symptoms and incarceration on sexual risk behavior and STI among Black sexual minority men, a population that may be at higher risk for contracting STIs. Using data from the HIV Prevention Trials Network 061 Study, a longitudinal study of adult Black sexual minority men in six U.S. cities (N = 855), we tested associations between past six-month incarceration and subsequent sexual risk behavior, STI, and depression symptoms, for those with and without pre-incarceration PTSD symptoms. PTSD symptoms were elevated among participants who reported Hispanic ethnicity, having sex with both men and women, and previous incarceration. Although there were not significant differences between recent incarceration and sexual risk for those with and without PTSD, incarceration was linked to some sexual risk behaviors regardless of PTSD symptoms. Among people with PTSD symptoms, there was a higher prevalence of sexual risk and depression symptoms, regardless of incarceration. These findings suggest a potentially compounding influence of PTSD symptoms and incarceration on sexual risk and infection among Black sexual minority men
Associations between police harassment and distrust in and reduced access to healthcare among Black sexual minority men: A longitudinal analysis of HPTN 061
Objective: Evaluate associations between racialized and homophobia-based police harassment (RHBPH) and healthcare distrust and utilization among Black Sexual Minority Men (BSMM). Methods: We utilized data from a longitudinal cohort study from HIV Prevention Trials Network (HPTN) 061 with baseline, six and 12 month follow-up assessments. Using multivariable analysis, we evaluated associations between RHBPH and healthcare distrust and utilization reported at the 6 and 12 month visits. Results: Of 1553 BSMM present at baseline, 1160 were available at six-month follow-up. In multivariable analysis, increasing frequency of RHBPH was associated with increasing levels of distrust in healthcare providers (aOR 1.31, 95% CI: 1.00, 1.74) and missing 50% or more of healthcare visits at six-month follow-up (aOR 1.93, 95% CI: 1.09, 3.43). Conclusions: Recent experiences of RHBPH are associated with reduced trust in and access to healthcare among BSMM, with more frequent RHBPH associated with greater vulnerability.</p
Age Differences in the Associations Between Incarceration and Subsequent Substance Use, Sexual Risk-Taking, and Incident STI Among Black Sexual Minority Men and Black Transgender Women in the HIV Prevention Trials 061 Cohort
Incarceration can lead to different risk behaviors often due to increased distress and disruption of social networks. It is not well known, however, how these associations may differ by age. In this study, we measure age differences in longitudinal associations between incarceration and substance use, sex risk, and sexually transmitted infection (STI) among Black sexual minority men and Black transgender women (BSMM/BTW). We recruited BSMM/BTW from 2009 to 2011 that were part of the HIV Prevention Trials Network 061 study. We compared those less than 30 years old (n = 375) to those 30 years old or greater (n = 794) examining substance use, sex risk, and STI infection stratified by age. Logistic regression with inverse probability weighting was used for the statistical analysis. Approximately 59% of the sample reported incarceration history. In adjusted analysis, incarceration was more strongly associated with alcohol use and stimulant use among older individuals as was sexual risk behaviors including buying and selling sex. Concurrent partnerships were associated with the younger age groups. STI incidence was associated with younger individuals while associations with HIV infection were similar for the two age groups. Understanding differences in substance use and STI risk among age cohorts is imperative to the design and implementation of re-entry programs. Younger BSMM/BTW participating in re-entry support programs may benefit in particular from HIV/STI prevention and care efforts, while post-release substance abuse treatment and harm reduction programs should target older individuals with continued substance abuse
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Pre-exposure prophylaxis initiation and adherence among Black men who have sex with men (MSM) in three US cities: results from the HPTN 073 study
Abstract : Introduction: Randomized clinical trials have demonstrated the efficacy of antiretroviral pre-exposure prophylaxis (PrEP) in preventing HIV acquisition among men who have sex with men (MSM). However, limited research has examined initiation and adherence to PrEP among Black MSM (BMSM) in the United States (US) who are disproportionately represented among newly HIV infected and late to care individuals. This research reports on the HIV Prevention Trials Network 073 (HPTN 073) study aimed to examine PrEP initiation, utilization and adherence among Black MSM utilizing the theoretically principled, cul- turally informed and client-centered care coordination (C4) model. Methods: The HPTN 073 study enrolled and followed 226 HIV-uninfected Black MSM in three US cities (Los Angeles, CA; Washington DC; and Chapel Hill, NC) from February 2013 through September 2015. Study participants were offered once daily oral emtricitabine/tenofovir (FTC/TDF) PrEP combined with C4 and followed up for 52 weeks. Participants received HIV testing, risk reduction education and clinical monitoring. Results: Of the 226 men enrolled, 178 participants initiated PrEP (79%), and of these 64% demonstrated PrEP utilization at week 26 (mid-point of the study) based on pharmacokinetic testing. Condomless anal sex with an HIV-infected or unknown status casual male partner was statistically significantly associated with a greater likelihood of PrEP initiation (adjusted odds ratio (OR) 4.4, 95% confidence interval (CI) 1.7, 11.7). Greater age (≥25 vs. <25, OR 2.95, 95% CI 1.37 –6.37), perception of having enough money (OR 3.6, 95% CI 1.7 to 7.7) and knowledge of male partner taking PrEP before sex (OR 2.22, 95% CI 1.03 to 4.79) were statistically significantly associated with increased likelihood of PrEP adherence at week 26. Annualized HIV incidence was 2.9 (95% CI 1.2 to 7.9) among those who initiated PrEP, compared to 7.7 (95% CI 2.5 to 24.1) among those who did not initiate PrEP (p = 0.18). Conclusions: Results suggest a high level of PrEP initiation among at-risk Black MSM, a group historically characterized as hard to reach. The data support the importance of addressing contextual factors that affect PrEP initiation and adherence, and of additional research on the ultimate benefit of PrEP in HIV prevention among Black MSM
Meta-analyses of genome-wide association studies for postpartum depression
Objective:
Postpartum depression (PPD) is a common subtype of major depressive disorder (MDD) that is more heritable, yet is understudied in psychiatric genetics. The authors conducted meta-analyses of genome-wide association studies (GWASs) to investigate the genetic architecture of PPD.
Method:
Meta-analyses were conducted on 18 cohorts of European ancestry (17,339 PPD cases and 53,426 controls), one cohort of East Asian ancestry (975 cases and 3,780 controls), and one cohort of African ancestry (456 cases and 1,255 controls), totaling 18,770 PPD cases and 58,461 controls. Post-GWAS analyses included 1) single-nucleotide polymorphism (SNP)–based heritability (), 2) genetic correlations between PPD and other phenotypes, and 3) enrichment of the PPD GWAS findings in 27 human tissues and 265 cell types from the mouse central and peripheral nervous system.
Results:
No SNP achieved genome-wide significance in the European or the trans-ancestry meta-analyses. The of PPD was 0.14 (SE=0.02). Significant genetic correlations were estimated for PPD with MDD, bipolar disorder, anxiety disorders, posttraumatic stress disorder, insomnia, age at menarche, and polycystic ovary syndrome. Cell-type enrichment analyses implicate inhibitory neurons in the thalamus and cholinergic neurons within septal nuclei of the hypothalamus, a pattern that differs from MDD.
Conclusions:
While more samples are needed to reach genome-wide levels of significance, the results presented confirm PPD as a polygenic and heritable phenotype. There is also evidence that despite a high correlation with MDD, PPD may have unique genetic components. Cell enrichment results suggest GABAergic neurons, which converge on a common mechanism with the only medication approved by the U.S. Food and Drug Administration for PPD (brexanolone)
Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals
Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice
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