Search tips
Search criteria

Results 1-25 (127)

Clipboard (0)

Select a Filter Below

more »
more »
Year of Publication
Document Types
2.  Dyadic effects of gender minority stressors in substance use behaviors among transgender women and their non-transgender male partners 
Despite evidence that interpersonal processes shape health behaviors, research concerning the dyadic effects of gender minority stressors on substance use behaviors of transgender people is scarce. The objective of this study was to use dyadic analysis to examine whether transgender discrimination was associated with substance use among transgender women and their male partners.
Transgender women and their male partners (N=191 couples; N=382 individuals) completed questionnaires. Participants’ mean age was 37.1; 79.1% were racial/ethnic minority; 61.3% earned <$500 per-month. The mean relationship duration was 37.9 months. Actor-Partner Interdependence Models were used to examine the associations between transgender-related discrimination and past 30-day non-marijuana illicit drug use adjusting for age, relationship length, financial hardship, and depressive distress among partners in these dyads.
Illicit drug use was reported by 31.4% of transgender women and 25.1% of their male partners. Perceived transgender discrimination was independently associated with increased odds of illicit drug use for transgender women (actor effect) but not for their male partners. Financial hardship statistically predicted drug use for both partners (actor effects). There were no partner effects for financial hardship on drug use. Overall, 34.5% of dyads had discrepant substance use. Discrimination scores of male partners differentiated dyads who reported discrepant substance use.
Gender minority stressors are critical to understanding substance use among transgender women and their male partners. Integrating socioeconomic status into gender minority stress frameworks is essential. Results have implications for substance use prevention and treatment, including the need to incorporate gender minority stressors into interventions.
PMCID: PMC4311402  PMID: 25642440
transgender women; substance use; couples; discrimination; financial hardship
3.  Thrombin induces ischemic LTP (iLTP): implications for synaptic plasticity in the acute phase of ischemic stroke 
Scientific Reports  2015;5:7912.
Acute brain ischemia modifies synaptic plasticity by inducing ischemic long-term potentiation (iLTP) of synaptic transmission through the activation of N-Methyl-D-aspartate receptors (NMDAR). Thrombin, a blood coagulation factor, affects synaptic plasticity in an NMDAR dependent manner. Since its activity and concentration is increased in brain tissue upon acute stroke, we sought to clarify whether thrombin could mediate iLTP through the activation of its receptor Protease-Activated receptor 1 (PAR1). Extracellular recordings were obtained in CA1 region of hippocampal slices from C57BL/6 mice. In vitro ischemia was induced by acute (3 minutes) oxygen and glucose deprivation (OGD). A specific ex vivo enzymatic assay was employed to assess thrombin activity in hippocampal slices, while OGD-induced changes in prothrombin mRNA levels were assessed by (RT)qPCR. Upon OGD, thrombin activity increased in hippocampal slices. A robust potentiation of excitatory synaptic strength was detected, which occluded the ability to induce further LTP. Inhibition of either thrombin or its receptor PAR1 blocked iLTP and restored the physiological, stimulus induced LTP. Our study provides important insights on the early changes occurring at excitatory synapses after ischemia and indicates the thrombin/PAR1 pathway as a novel target for developing therapeutic strategies to restore synaptic function in the acute phase of ischemic stroke.
PMCID: PMC4300504  PMID: 25604482
4.  Potential Impact and Acceptability of Internet Partner Notification for Men Who Have Sex with Men and Transgender Women Recently Diagnosed with STD in Lima, Peru 
Sexually transmitted diseases  2014;41(1):43-45.
We assessed the potential impact of internet partner notification (PN) among MSM and transgender women in Peru recently diagnosed with STD. Use of internet PN was anticipated for 55.9% of recent partners, including 43.0% of partners not currently expected to be notified, a 20.6% increase in anticipated notification outcomes.
PMCID: PMC3932828  PMID: 24326581
Men Who Have Sex With Men; Transgender Women; Partner Notification; Sexually Transmitted Disease; Peru
5.  Transgender Health Disparities: Comparing Full Cohort and Nested Matched-Pair Study Designs in a Community Health Center 
LGBT health  2014;1(3):177-184.
U.S. health surveillance systems infrequently include measures to identify transgender respondents or monitor the health of this underserved and marginalized population.
From 2001–2002, transgender and non-transgender adults were sampled at a Massachusetts clinic. Health differences were formatively examined by transgender identity using a cross-sectional, clinic-based sample (n=2,653); and a nested matched-pair subsample (n=155).
Both designs produced virtually identical findings: (1) the prevalence of HIV, substance abuse, and smoking did not differ significantly for transgender and non-transgender patients; (2) transgender patients were more likely to endorse a lifetime suicide attempt and ideation compared to non-transgender patients (p<0.05); (3) transgender patients disproportionately reported social stressors (violence, discrimination, childhood abuse) relative to non-transgender patients (p<0.05).
Findings suggest that a nested design may provide an effective methodology for using clinical data to study transgender health, and underscore the need for routine collection of gender identity in clinical settings.
PMCID: PMC4219512  PMID: 25379511
Health disparity; transgender; gender identity; methods; study design
6.  Progressive Degeneration of Dopaminergic Neurons through TRP Channel-Induced Cell Death 
The Journal of Neuroscience  2014;34(17):5738-5746.
Progressive neurodegenerative diseases are among the most frequently occurring aging-associated human pathologies. In a screen for Caenorhabditis elegans mutant animals that lack their normal complement of dopaminergic neurons, we identified two strains with progressive loss of dopaminergic neurons during postembryonic life. Through whole-genome sequencing we show that both strains harbor dominant (d), gain-of-function mutations in the Transient Receptor Potential (TRP) mechanosensory channel trp-4, a member of the invertebrate and vertebrate TRPN-type of the TRP family channels. Gain-of-function mutations in TRP channels have not been previously implicated in dopaminergic neuronal degeneration. We show that trp-4(d) induces cell death in dopamine neurons through a defined, calcium-related downstream pathway.
PMCID: PMC3996206  PMID: 24760834
C. elegans; calcium; cell death; dopaminergic neurons; neurodegeneration; TRP channels
7.  Commentary 
PMCID: PMC4173242  PMID: 25288847
8.  Distance dependent charge separation and recombination in semiconductor/molecular catalyst systems for water splitting† †Electronic supplementary information (ESI) available: Experimental details, DFT calculations and additional transient absorption measurements. See DOI: 10.1039/c4cc05143b Click here for additional data file.  
The molecular structure of the catalyst strongly influences the kinetics of charge separation and recombination.
The photoinduced reduction of three Co electrocatalysts immobilised on TiO2 is 104 times faster than the reverse charge recombination. Both processes show an exponential dependence on the distance between the semiconductor and the catalytic core.
PMCID: PMC4183993  PMID: 25207748
9.  Type 1 Fimbriae Contribute to Catheter-Associated Urinary Tract Infections Caused by Escherichia coli 
Journal of Bacteriology  2014;196(5):931-939.
Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI), which represent the most frequent nosocomial infections. Knowledge of genetic factors for catheter colonization is limited, since their role has not been assessed using physicochemical conditions prevailing in a catheterized human bladder. The current study aimed to combine data from a dynamic catheterized bladder model in vitro with in vivo expression analysis for understanding molecular factors relevant for CAUTI caused by Escherichia coli. By application of the in vitro model that mirrors the physicochemical environment during human infection, we found that an E. coli K-12 mutant defective in type 1 fimbriae, but not isogenic mutants lacking flagella or antigen 43, was outcompeted by the wild-type strain during prolonged catheter colonization. The importance of type 1 fimbriae for catheter colonization was verified using a fimA mutant of uropathogenic E. coli strain CFT073 with human and artificial urine. Orientation of the invertible element (IE) controlling type 1 fimbrial expression in bacterial populations harvested from the colonized catheterized bladder in vitro suggested that the vast majority of catheter-colonizing cells (up to 88%) express type 1 fimbriae. Analysis of IE orientation in E. coli populations harvested from patient catheters revealed that a median level of ∼73% of cells from nine samples have switched on type 1 fimbrial expression. This study supports the utility of the dynamic catheterized bladder model for analyzing catheter colonization factors and highlights a role for type 1 fimbriae during CAUTI.
PMCID: PMC3957706  PMID: 24336940
10.  Development and Validation of a Portable Platform for Deploying Decision-Support Algorithms in Prehospital Settings 
Applied Clinical Informatics  2013;4(3):392-402.
Advanced decision-support capabilities for prehospital trauma care may prove effective at improving patient care. Such functionality would be possible if an analysis platform were connected to a transport vital-signs monitor. In practice, there are technical challenges to implementing such a system. Not only must each individual component be reliable, but, in addition, the connectivity between components must be reliable.
We describe the development, validation, and deployment of the Automated Processing of Physiologic Registry for Assessment of Injury Severity (APPRAISE) platform, intended to serve as a test bed to help evaluate the performance of decision-support algorithms in a prehospital environment.
We describe the hardware selected and the software implemented, and the procedures used for laboratory and field testing.
The APPRAISE platform met performance goals in both laboratory testing (using a vital-sign data simulator) and initial field testing. After its field testing, the platform has been in use on Boston MedFlight air ambulances since February of 2010.
These experiences may prove informative to other technology developers and to healthcare stakeholders seeking to invest in connected electronic systems for prehospital as well as in-hospital use. Our experiences illustrate two sets of important questions: are the individual components reliable (e.g., physical integrity, power, core functionality, and end-user interaction) and is the connectivity between components reliable (e.g., communication protocols and the metadata necessary for data interpretation)? While all potential operational issues cannot be fully anticipated and eliminated during development, thoughtful design and phased testing steps can reduce, if not eliminate, technical surprises.
PMCID: PMC3799209  PMID: 24155791
Decision-support algorithms; prehospital care; device connectivity; vital-sign data; combat casualty care
11.  Gender minority stress, mental health, and relationship quality: A dyadic investigation of transgender women and their cisgender male partners 
Research has demonstrated associations between experiences of discrimination, relationship quality, and mental health. However, critical questions remain unanswered with regard to how stigma enacted and experienced at the dyadic-level influences relationship quality and mental health for transgender women and their cisgender (non-transgender) male partners. The present study sought to examine how experiences of transgender-related discrimination (i.e., unfair treatment, harassment) and relationship stigma (i.e., the real or anticipated fear of rejection based on one’s romantic affiliation), were associated with both partners relationship quality and mental health. Couples (N=191) were recruited to participate in cross-sectional survey. Actor-partner interdependence models (APIM) were fit to examine the influence of minority stressors on clinically significant depressive distress and relationship quality. For both partners, financial hardship, discrimination, and relationship stigma were associated with an increased odds of depressive distress. For both partners, financial hardship was associated with lower relationship quality. Among transgender women, their own and their partner’s higher relationship stigma scores were associated with lower relationship quality; however, among male partners, only their partner’s greater relationship stigma scores were associated with lower relationship quality. Findings provide preliminary support for dyadic crossover effects of relationship stigma on the health of partners. Findings illustrate the importance of minority stress and dyadic stress frameworks in understanding and intervening upon mental health disparities among transgender women and their male partners. Couples-based interventions and treatment approaches to help transgender women and their male partners cope with minority stressors are warranted to improve the health and well-being of both partners.
PMCID: PMC4122619  PMID: 24932942
Transgender; couples; relationship stigma; mental health; relationship quality
12.  Substance Use Among HIV-Infected Patients Engaged in Primary Care in the United States: Findings From the Centers for AIDS Research Network of Integrated Clinical Systems Cohort 
American journal of public health  2013;103(8):1457-1467.
The purpose of this study was to better understand substance use behaviors and deleterious health consequences among individuals with HIV.
We examined a multicenter cohort of HIV-infected patients (n = 3413) receiving care in 4 US cities (Seattle, Birmingham, San Diego, Boston) between December 2005 and April 2010 in the Centers for AIDS Research Network of Integrated Clinical Systems (CNICS). We used generalized estimating equations to model specific substance use outcomes.
Overall, 24% of patients reported recent use of marijuana; 9% reported amphetamine use, 9% reported crack–cocaine use, 2% reported opiate use, 3.8% reported injection drug use, and 10.3% reported polydrug use. In adjusted multivariable models, those who reported unprotected anal sex had higher odds of marijuana, amphetamine, injection drug, and polydrug use. An increased number of distinct vaginal sexual partners was associated with polydrug and crack–cocaine use. Nonadherence to antiretroviral therapy was associated with the use of all substances other than marijuana.
The co-occurrence of substance use, unprotected intercourse, and medication nonadherence could attenuate the public health benefits of test, treat, and link to care strategies. Prevention programs are needed that address these coprevalent conditions.
PMCID: PMC3752382  PMID: 23763417
13.  Global Burden of HIV among Men Who Engage in Transactional Sex: A Systematic Review and Meta-Analysis 
PLoS ONE  2014;9(7):e103549.
Men who engage in transactional sex, the exchange of sex for money, goods, or other items of value, are thought to be at increased risk of HIV, but there have been no systematic attempts to characterize HIV burden in this population. We undertook a systematic review and meta-analysis to quantify the burden in this population compared with that of men in the general population to better inform future HIV prevention efforts.
We searched seven electronic databases, national surveillance reports, and conference abstracts for studies of men who engage in transactional sex published between 2004–2013. Random effects meta-analysis was used to determine pooled HIV prevalence and prevalence ratios (PR) for the difference in HIV prevalence among men who engage in transactional sex as compared to general population men.
Of 66 studies included representing 31,924 men who had engaged in transactional sex in 28 countries, pooled biological assay-confirmed HIV prevalence was 10.5% (95% CI = 9.4 to 11.5%). The highest pooled HIV prevalence was in Sub-Saharan Africa (31.5%, 95% CI = 21.6 to 41.5%), followed by Latin America (19.3%, 95% CI = 15.5 to 23.1%), North America (16.6%, 95% CI = 3.7 to 29.5%), and Europe (12.2%, 95% CI = 6.0 to 17.2%). Men who engaged in transactional sex had an elevated burden of HIV compared to the general male population (PR = 20.7, 95% CI = 16.8 to 25.5).
The global burden of HIV is disproportionately high among men who engage in transactional sex compared with the general male population. There is an urgent need to include this population in systematic surveillance as well as to scale-up access to quality HIV prevention programs.
PMCID: PMC4113434  PMID: 25068720
14.  Randomized study of the safety, pharmacokinetics, and bronchodilatory efficacy of a proprietary glycopyrronium metered-dose inhaler in study patients with chronic obstructive pulmonary disease 
BMC Pulmonary Medicine  2014;14:118.
Bronchodilator medications are central to the symptomatic management of chronic obstructive pulmonary disease (COPD). Metered-dose inhalers (MDIs) are the most commonly used devices to deliver treatment to patients with COPD and asthma, comprising approximately 70% of bronchodilator prescriptions. Proprietary porous-particle technology permits the formulation of long-acting muscarinic antagonists, long-acting β2-agonists, and a combination of both in hydrofluoroalkane (HFA) MDIs, providing a solution to formulation challenges inherent to the development of HFA MDIs, which have contributed to the development of dry-powder inhalers.
In this randomized, double-blind, 4-period, 6-treatment, placebo- and active-controlled, multicenter, crossover study, 4 ascending single doses of a proprietary glycopyrronium (GP) MDI were evaluated compared with Placebo MDI and open-label tiotropium (TIO) in study patients with COPD. Thirty-three study patients were enrolled and received single-dose administration of 4 of the 6 treatments (Placebo MDI, TIO 18 μg, or GP MDI at 14.4, 28.8, 57.6, and 115.2 μg ex-actuator) with an interval of 1 to 3 weeks between doses. The primary efficacy endpoint was peak change in forced expiratory volume in 1 second (FEV1).
All 4 doses of GP MDI showed statistically superior efficacy compared with Placebo MDI for peak FEV1 (differences of 146 to 248 mL; P < .001), with a clear dose ordering of the response. Statistically significant differences compared with Placebo MDI were noted at almost all doses for the secondary FEV1 parameters (P ≤ .049) except 24-hour trough FEV1 at 28.8 μg. All doses were safe and well tolerated in this study; the most frequently reported adverse event was dry mouth (0–14.3% across doses; 9.5% for Placebo MDI, and 9.1% for TIO).
This study demonstrated superior bronchodilatory efficacy of GP MDI compared with Placebo MDI at all doses tested, and no serious adverse events were reported. This study supports the further evaluation of GP MDI in study patients with COPD. In addition, these findings indicate that the correct dosage of glycopyrronium is no more than 115.2 μg total daily dose, or 57.6 μg twice daily based on comparisons with the active comparator.
Trial registration
This clinical trial was registered on, Identifier: NCT00871182.
PMCID: PMC4124171  PMID: 25027304
Chronic obstructive pulmonary disease; Glycopyrronium; Porous particle technology; Long-acting anticholinergic; Long-acting muscarinic antagonist
15.  HIV Sexual Risk Behavior among Black Men Who Meet Other Men on the Internet for Sex 
Using the Internet to meet sexual partners is associated with increased HIV risk behavior, including substance use, sex with multiple or anonymous partners, and unprotected anal sex (UAS), among diverse samples of MSM, yet little is known about Internet use and HIV risk among Black MSM specifically. In 2008, a sample of 197 Black MSM completed an interviewer-administered assessment and voluntary HIV counseling and testing. One fifth of the sample (20 %) reported meeting a sexual partner via the Internet in the past 12 months. Men who met sexual partners over the Internet had significantly more male sex partners (M = 13.44, SD = 20.01) than men who did not meet partners in this manner (M = 4.11, SD = 4.14, p < 0.001) and reported significantly higher rates of UAS (p < 0.05). Adjusting for sociodemographic and other HIV-related covariates, factors significantly associated with the increased odds of engaging in at least one episode of UAS with a male partner in the past 12 months included: meeting sexual partners on the Internet, identifying as gay, and lower knowledge about HIV transmission. These findings highlight the unique HIV risk behaviors among Black MSM meeting sexual partners via the Internet and warrant tailoring of prevention activities to address the specific behaviors and social influences that may contribute to increased HIV spread among this population.
PMCID: PMC3665969  PMID: 22689294
MSM; Internet; African American/Black; HIV; Sexual risk
16.  Common Requirement for the Relaxosome of Plasmid R1 in Multiple Activities of the Conjugative Type IV Secretion System 
Journal of Bacteriology  2014;196(11):2108-2121.
Macromolecular transport by bacterial type IV secretion systems involves regulated uptake of (nucleo)protein complexes by the cell envelope-spanning transport channel. A coupling protein receptor is believed to recognize the specific proteins destined for transfer, but the steps initiating their translocation remain unknown. Here, we investigate the contribution of a complex of transfer initiation proteins, the relaxosome, of plasmid R1 to translocation of competing transferable substrates from mobilizable plasmids ColE1 and CloDF13 or the bacteriophage R17. We found that not only does the R1 translocation machinery engage the R1 relaxosome during conjugative self-transfer and during infection by R17 phage but it is also activated by its cognate relaxosome to mediate the export of an alternative plasmid. Transporter activity was optimized by the R1 relaxosome even when this complex itself could not be transferred, i.e., when the N-terminal activation domain (amino acids 1 to 992 [N1-992]) of TraI was present without the C-terminal conjugative helicase domain. We propose that the functional dependence of the transfer machinery on the R1 relaxosome for initiating translocation ensures that dissemination of heterologous plasmids does not occur at the expense of self-transfer.
PMCID: PMC4010989  PMID: 24682328
17.  Fetal Pancreas as a Source for Islet Transplantation 
Diabetes  2013;62(5):1382-1383.
PMCID: PMC3636611  PMID: 23613558
19.  Repeated Changes in Reported Sexual Orientation Identity Linked to Substance Use Behaviors in Youth 
Previous studies have found that sexual minority (e.g., lesbian, gay, bisexual) adolescents are at higher risk of substance use than heterosexuals, but few have examined how changes in sexual orientation over time may relate to substance use. We examined the associations between change in sexual orientation identity and marijuana use, tobacco use, and binge drinking in U.S. youth.
Prospective data from 10,515 U.S. youth ages 12-27 years in a longitudinal cohort study were analyzed using sexual orientation identity mobility measure M (frequency of change from 0 [no change] to 1 [change at every wave]) in up to five waves of data. Generalized estimating equations were used to estimate substance use risk ratios and 95% confidence intervals; interactions by sex and age group were assessed.
All substance use behaviors varied significantly by sexual orientation. Sexual minorities were at higher risk for all outcomes, excluding binge drinking in males, and mobility score was positively associated with substance use in most cases (p<.05). The association between mobility and substance use remained significant after adjusting for current sexual orientation and varied by sex and age for selected substance use behaviors. This association had a higher positive magnitude in females than males and in adolescents than young adults.
In both clinical and research settings it is important to assess history of sexual orientation changes. Changes in reported sexual orientation over time may be as important as current sexual orientation for understanding adolescent substance use risk.
PMCID: PMC3608814  PMID: 23298999
Substance use; tobacco; alcohol; marijuana; sexual orientation; lesbian; gay; bisexual
20.  Walking the line: Stimulant use during sex and HIV risk behavior among Black urban MSM 
Drug and alcohol dependence  2010;110(0):30-37.
Although the association of stimulant use to sexual risk taking and HIV transmission has been well documented among white gay men, stimulant use during sex continues to be under-explored among Black men who have sex with men (MSM).
Black MSM (n = 197) recruited via modified respondent-driven sampling between January and July 2008 completed an interviewer-administered quantitative assessment and optional HIV counseling and testing. Bivariate logistic regression procedures were employed to examine the association of demographics, sexual risk, and other psychosocial factors with stimulant use (at least monthly during sex in the past 12 months). Variable elimination using the backward selection process was used to fit two separate final multivariable logistic regression models examining stimulant use as the outcome and HIV sexual risk in the past 12 months by gender as the primary predictor: (1) Model 1: HIV sexual risk behavior with a casual male sex partner as a primary, forced predictor; (2) Model 2: HIV sexual risk behavior with a female sex partner as primary, forced predictor.
One-third (34%) of Black MSM reported using stimulants monthly or more frequently during sex in the past 12 months. The following factors were independently associated with stimulant use during sex: (1) Model 1: unprotected anal sex with a casual male sex partner in the past 12 months (AOR = 2.61; 95% CI = 1.06–6.42; p = 0.01), older age (AOR = 1.09; 95% CI = 1.05–1.15; p < 0.001), erectile dysfunction (ED) medication use monthly or more during sex in the past 12 months (AOR = 7.81; 95% CI = 1.46–41.68; p = 0.02), problematic alcohol use (AOR = 3.31; 95% CI = 1.312–8.38; p = 0.005), and higher HIV treatment optimism (AOR = 0.86; 95% CI = 0.76–0.97; p = 0.01). (2) Model 2: unprotected vaginal or anal sex with a female partner in the past 12 months (AOR = 3.54; 95% CI = 1.66–7.56; p = 0.001), older age (AOR = 1.10; 95% CI = 1.05–1.14; p < 0.001), ED use monthly or more during sex in the past 12 months (AOR = 3.70; 95% CI = 1.13–12.13; p = 0.03), clinically significant depressive symptoms (CES-D) at the time of study enrollment (AOR = 3.11; 95% CI = 1.45–6.66; p = 0.004), and supportive condom use norms (AOR = 0.69; 95% CI = 0.49–0.97; p = 0.03).
Frequent stimulant use is an important factor in HIV and STD sexual risk among Black MSM, particularly for older men and those with co-occurring psychosocial morbidities. HIV and STD prevention interventions in this population may benefit from addressing the precipitants of stimulant use and sexual risk taking.
PMCID: PMC3947405  PMID: 20334986
Stimulant use; Black; MSM; HIV; Sexual risk behavior
21.  Clinically Significant Depressive Symptoms as a Risk Factor for HIV Infection Among Black MSM in Massachusetts 
AIDS and behavior  2009;13(4):798-810.
High rates of depression have been observed among men who have sex with men (MSM) relative to the general adult male population; however, a dearth of research has explored depression among Black MSM. Black MSM (n = 197) recruited via modified respondent-driven sampling between January and July 2008 completed an interviewer-administered quantitative assessment and voluntary HIV counseling and testing. Bivariate and multivariable logistic regression procedures examined the associations of demographics, behavioral HIV risk factors, and psychosocial variables with depressive symptoms by severity, using the 20-item Center for Epidemiologic Studies Depression Scale (CES-D). Adjusting for demographic and behavioral variables, significant factors associated with (1) clinically significant depressive symptoms (33%; CES-D score ≥ 16): being publicly insured by Medicaid, having serodiscordant anal sex with a casual male partner, and being diagnosed with an STD in the prior 12 months; (2) moderate depressive symptoms (19%; CES-D score 16–26): having serodiscordant unprotected anal sex with a casual male partner and being diagnosed with an STD in the prior 12 months; (3) severe depressive symptoms (14%; CES-D score 27+): being publicly insured by Medicaid and reporting difficulty accessing healthcare in the past 12 months. Moderately depressed Black MSM may be more likely to engage in behaviors that place them at increased risk for HIV and other STDs. HIV prevention interventions for Black MSM may benefit from incorporating screening and/or treatment for depression, allowing MSM who are depressed to respond more effectively to behavioral change approaches.
PMCID: PMC3947411  PMID: 19462228
MSM; Depression; African American; HIV; STD
22.  Sexual Orientation Disparities in Substance Misuse: The Role of Childhood Abuse and Intimate Partner Violence Among Patients in Care at an Urban Community Health Center 
Substance use & misuse  2013;48(3):274-289.
This study examined disparities in lifetime substance misuse by sexual orientation among 2,653 patients engaged in care at an urban community health center in Boston, MA, as well as the potential mediating roles of childhood abuse
PMCID: PMC3918899  PMID: 23368669
Substance abuse; violence; sexual orientation; health disparities
The generation of renewable H2 through an efficient photochemical route requires photoinduced electron transfer (ET) from a light harvester to an efficient electrocatalyst in water. Here, we report on a molecular H2 evolution catalyst (NiP) with a DuBois-type [Ni(P2R′N2R″)2]2+ core (P2R′N2R″ = bis(1,5-R′-diphospha-3,7-R″-diazacyclooctane), which contains an outer coordination sphere with phosphonic acid groups. The latter functionality allows for good solubility in water and immobilization on metal oxide semiconductors. Electrochemical studies confirm that NiP is a highly active electrocatalyst in aqueous electrolyte solution (overpotential of approximately 200 mV at pH 4.5 with a Faradaic yield of 85 ± 4%). Photocatalytic experiments and investigations on the ET kinetics were carried out in combination with a phosphonated Ru(II) tris(bipyridine) dye (RuP) in homogeneous and heterogeneous environments. Time-resolved luminescence and transient absorption spectroscopy studies confirmed that directed ET from RuP to NiP occurs efficiently in all systems on the nano- to microsecond time scale, through three distinct routes: reductive quenching of RuP in solution or on the surface of ZrO2 (“on particle” system) or oxidative quenching of RuP when the compounds were immobilized on TiO2 (“through particle” system). Our studies show that NiP can be used in a purely aqueous solution and on a semiconductor surface with a high degree of versatility. A high TOF of 460 ± 60 h–1 with a TON of 723 ± 171 for photocatalytic H2 generation with a molecular Ni catalyst in water and a photon-to-H2 quantum yield of approximately 10% were achieved for the homogeneous system.
PMCID: PMC3901378  PMID: 24320740
AIDS Patient Care and STDs  2012;26(11):681-693.
Crystal methamphetamine use is a major driver behind high-risk sexual behavior among men who have sex with men (MSM). Prior work suggests a cycle of continued crystal methamphetamine use and high-risk sex due to loss of the ability to enjoy other activities, which appears to be a side effect of this drug. Behavioral activation (BA) is a treatment for depression that involves learning to reengage in life's activities. We evaluated a novel intervention for crystal methamphetamine abuse and high-risk sex in MSM, incorporating 10 sessions of BA with integrated HIV risk reduction counseling (RR). Forty-four subjects were screened, of whom 21 met initial entry criteria. A total of 19 participants enrolled; 16 completed an open-phase study of the intervention. Behavioral assessments were conducted at baseline, 3 months postbaseline, and 6 months postbaseline. Linear mixed effects regression models were fit to assess change over time. Mean unprotected anal intercourse (UAI) episodes decreased significantly from baseline to acute postintervention (β=−4.86; 95% confidence interval [CI]=−7.48, −2.24; p=0.0015) and from baseline to 6 months postbaseline (β=−5.07; 95% CI=−7.85, −2.29; p=0.0017; test of fixed effects χ2=16.59; df=2,13; p=0.0002). On average, there was a significant decrease over time in the number of crystal methamphetamine episodes in the past 3 months (χ2=22.43; df=2,15; p<0.0001), and the number of days of crystal methamphetamine use in the past 30 days (χ2=9.21; df=2,15; p=0.010). Statistically significant reductions in depressive symptoms and poly-substance use were also maintained. Adding behavioral activation to risk reduction counseling for MSM with problematic crystal methamphetamine use may augment the potency of a risk reduction intervention for this population. Due to the small sample size and time intensive intervention, future testing in a randomized design is necessary to determine efficacy, with subsequent effectiveness testing.
PMCID: PMC3495110  PMID: 23030605
Journal of the American Chemical Society  2013;135(29):10610-10613.
Photosystem II (PSII) offers a biological and sustainable route of photochemical water oxidation to O2 and can provide protons and electrons for the generation of solar fuels, such as H2. We present a rational strategy to electrostatically improve the orientation of PSII from a thermophilic cyanobacterium, Thermosynechococcus elongatus, on a nanostructured indium tin oxide (ITO) electrode and to covalently immobilize PSII on the electrode. The ITO electrode was modified with a self-assembled monolayer (SAM) of phosphonic acid ITO linkers with a dangling carboxylate moiety. The negatively charged carboxylate attracts the positive dipole on the electron acceptor side of PSII via Coulomb interactions. Covalent attachment of PSII in its electrostatically improved orientation to the SAM-modified ITO electrode was accomplished via an amide bond to further enhance red-light-driven, direct electron transfer and stability of the PSII hybrid photoelectrode.
PMCID: PMC3795471  PMID: 23829513

Results 1-25 (127)