Methamphetamine and Viagra Use: Relationship to Sexual Risk Behaviors

Recent studies show that Viagra and methamphetamine use are associated with unprotected anal intercourse among men who have sex with men (MSM). In Long Beach, California, we have reported on an association between Viagra use and the use of amphetamines during sex. The current research investigated the use of both Viagra and amphetamine in men in Long Beach, California. Data on 1,839 men recruited into HIV prevention and testing programs were collected using the Risk Behavior Assessment. A generalized logit model was constructed comparing ever having used both amphetamine and Viagra together and separately, as compared to never having used either (referent). Men who used both methamphetamine and Viagra showed a significantly higher prevalence of hepatitis B, syphilis, and HIV compared to those who used only one or neither drug. Of the 1,794 complete cases, 11.1% (199/1794) had used both amphetamine and Viagra. Of 20 potential risk and protective factors for use of amphetamine and Viagra, 12 were significant predictors: ever used gamma-hydroxybutyrate (GHB), ever used cocaine, ever used ecstasy, being infected with HIV, race = White compared to other, ever having hepatitis B, ever using crack, ever given money to have sex, living in a hotel, ever been in drug treatment, and ever using heroin. The protective factor was being heterosexual. Viagra use was associated with insertive, and methamphetamine was associated with receptive, anal intercourse. GHB use appears to play a more important role than previously thought

Using a Modified Intervention Mapping Approach to Develop and Refine a Single-Session Motivational Intervention for Methamphetamine-Using Men Who Have Sex With Men

There is an ongoing need for the development and adaptation of behavioral interventions to address behaviors related to acquisition and transmission of infectious diseases and for preventing the onset of chronic diseases. This paper describes the application of an established systematic approach to the development of a behavioral intervention to reduce sexual risk behaviors for HIV among men who have sex with men and who use methamphetamine. The approach includes six steps: (1) a needs assessment; (2) preparing matrices of proximal program objectives; (3) selecting theory-based methods and practical strategies; (4) producing program components and materials; (5) planning for program adoption, implementation, and sustainability; and (6) planning for evaluation. The focus of this article is on the intervention development process; therefore the article does not describe steps 5 and 6. Overall the process worked well, although it had to be adapted to fit the sequence of events associated with a funded research project. This project demonstrates that systematic approaches to intervention development can be applied even in research projects where some of the steps occur during the proposal writing process rather than during the actual project. However, intervention developers must remain flexible and be prepared to adapt the process to the situation. This includes being ready to make choices regarding intervention efficacy versus feasibility and being willing to select the best intervention that is likely to be delivered with available resources rather than an ideal intervention that may not be practical

Polydrug Use among IDUs in Tijuana, Mexico: Correlates of Methamphetamine Use and Route of Administration by Gender

Tijuana is situated on the Mexico–USA border adjacent to San Diego, CA, on a major drug trafficking route. Increased methamphetamine trafficking in recent years has created a local consumption market. We examined factors associated with methamphetamine use and routes of administration by gender among injection drug users (IDUs). From 2006–2007, IDUs ≥18 years old in Tijuana were recruited using respondent-driven sampling, interviewed, and tested for HIV, syphilis, and TB. Logistic regression was used to assess associations with methamphetamine use (past 6 months), stratified by gender. Among 1,056 participants, methamphetamine use was more commonly reported among females compared to males (80% vs. 68%, p < 0.01), particularly, methamphetamine smoking (57% vs. 34%; p < 0.01). Among females (N = 158), being aged >35 years (AOR, 0.2; 95% CI, 0.1–0.6) was associated with methamphetamine use. Among males (N = 898), being aged >35 years (AOR, 0.5; 95% CI, 0.3–0.6), homeless (AOR, 1.4 (0.9–2.2)), and ever reporting sex with another male (MSM; AOR, 1.9; 95% CI, 1.4–2.7) were associated with methamphetamine use. Among males, a history of MSM was associated with injection, while sex trade and >2 casual sex partners were associated with multiple routes of administration. HIV was higher among both males and females reporting injection as the only route of methamphetamine administration. Methamphetamine use is highly prevalent among IDUs in Tijuana, especially among females. Routes of administration differed by gender and subgroup which has important implications for tailoring harm reduction interventions and drug abuse treatment

Properties of Graphene: A Theoretical Perspective

In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect, and optical properties. Confinement of electrons in graphene is nontrivial due to Klein tunneling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane -- gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic

Methamphetamine Use, Transmission Risk Behavior and Internet Use Among HIV-Infected Patients in Medical Care, San Francisco, 2008

Methamphetamine use is associated with adverse health outcomes and HIV incidence. Few studies have assessed methamphetamine use, sexual behavior and Internet use among HIV-infected patients. Surveys were administered to a sample of HIV-infected patients seeking medical care in a San Francisco county hospital and university-based clinic. In 2008, 35% of homosexual participants, 26% of heterosexual participants and 11% of female participants reported methamphetamine use in the past year. Of participants, 29% reported using the Internet to find sex partners; Internet-users versus non-Internet-users reported a higher median number of sex partners in 6 months (4 vs. 1), were more likely to report unprotected sex (32 vs. 10%), and higher rates of methamphetamine use in the past 12 months (48 vs. 24%). Given the association among methamphetamine use, increased sex partners and Internet use, the Internet may present a new and effective medium for interventions to reduce methamphetamine-associated sexual risk behavior

Oxidative discolouration in whole-head and cut lettuce: biochemical and environmental influences on a complex phenotype and potential breeding strategies to improve shelf-life

Lettuce discolouration is a key post-harvest trait. The major enzyme controlling oxidative discolouration has long been considered to be polyphenol oxidase (PPO) however, levels of PPO and subsequent development of discolouration symptoms have not always correlated. The predominance of a latent state of the enzyme in plant tissues combined with substrate activation and contemporaneous suicide inactivation mechanisms are considered as potential explanations for this phenomenon. Leaf tissue physical properties have been associated with subsequent discolouration and these may be influenced by variation in nutrient availability, especially excess nitrogen and head maturity at harvest. Mild calcium and irrigation stress has also been associated with a reduction in subsequent discolouration, although excess irrigation has been linked to increased discolouration potentially through leaf physical properties. These environmental factors, including high temperature and UV light intensities, often have impacts on levels of phenolic compounds linking the environmental responses to the biochemistry of the PPO pathway. Breeding strategies targeting the PALand PPOpathway biochemistry and environmental response genes are discussed as a more cost-effective method of mitigating oxidative discolouration then either modified atmosphere packaging or post-harvest treatments, although current understanding of the biochemistry means that such programs are likely to be limited in nature and it is likely that they will need to be deployed alongside other methods for the foreseeable future

Peer Victimization and Poor Academic Outcomes in Adolescents With ADHD: What Individual Factors Predict Risk?

Objective: Examine individual factors associated with peer victimization (PV) in adolescents with attention-deficit/hyperactivity disorder (ADHD) and to examine the association between PV and educational outcomes. Method: Participants were 121 adolescents ( Mage = 13.62, SD = 1.03; 89% boys) with diagnosed ADHD. Using path analysis, we tested whether general adolescent factors (ADHD symptoms, comorbid autism spectrum disorder, cognitive and social functioning, and age) were associated with experiences of PV, and associations between PV and academic outcomes. Results: Deficits in working memory (WM) and peer relationship problems were weakly and moderately associated with PV, respectively. PV was in turn was associated with adolescents’ attitudes about school, academic competence, and academic achievement. Conclusion: Adolescents with poor social skills and/or WM difficulties who have ADHD may be particularly vulnerable to being victimized by peers. Failure to identify and manage PV during early adolescence may be connected to poor educational outcomes. </jats:p

Methamphetamine Use Trends among Street-Recruited Gay and Bisexual Males, from 1999 to 2007

Street outreach encounters were used to collect data of reported alcohol and other drug use among gay and bisexual males (N = 11,375) in Hollywood and West Hollywood, California over a 9-year period from January 1999 to December 2007. Analyses were conducted to assess demographic data, self-reported HIV status, and frequency of alcohol and other drug use. Participants averaged 32.3 (SD = 7.7) years, slightly over half were Caucasian/white (53%), and most were identified as gay (85.8%). Self-reported HIV seroprevalence was 20.7%. Observations began January to June 1999, with 46.0% reporting recent methamphetamine use, and ended July to December 2007, with 24.8% reporting recent use of methamphetamine. Percent reporting methamphetamine use peaked in the first half of 2002 at 53% and dipped to a low of 11.1% in the second half of 2006. Findings demonstrate the common use of methamphetamine over the observation period in this high-risk group even in the face of a recent decline in reported use. These data also indicate the need for ongoing methamphetamine abuse and HIV-prevention interventions in this particular high-risk population

Sexual and Injection Risk among Women who Inject Methamphetamine in San Francisco

Methamphetamine (MA) use is on the rise in the United States, with many cities reporting increases of 100% or more in MA-related Emergency Department (ED) mentions. Women are keeping pace with this trend: in 2003, 40% of ED mentions and 45% of MA-related treatment admissions were female. Although there have been extensive examinations of MA use and HIV/STI risk among gay men in recent years, literature regarding female MA users is scarce. This paper examines female methamphetamine injectors in San Francisco, CA, from 2003–2005. We assessed sexual and injection related risk behaviors, comparing female MA injectors to female injectors of other drugs. We also examined whether MA use was independently associated with specific sexual and injection risk behaviors. We found that female MA injectors were significantly more likely than non-MA injectors to report unprotected anal intercourse, multiple sexual partners, receptive syringe sharing and sharing of syringes with more than one person in the past six months. In multivariate analysis, MA use among female injectors was significantly associated with anal sex, more than five sexual partners, receptive syringe sharing, and more than one syringe-sharing partner in the past six months. Deeper exploration of the relationship between MA use and sexual risk among women would benefit HIV/STI prevention efforts. In addition, existing interventions for drug-injecting women may need to be adapted to better meet the risks of female MA injectors