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Background: American Indian/Alaska Native (AI/AN) men who have sex with men (MSM) are at high risk of human immunodeficiency virus (HIV) acquisition and transmission.Purpose: This study aimed to investigate a potential area of focus for HIV prevention interventions by assessing the impact of sexual risk cognitions on sexual risk-taking among AI/AN MSM.Methods: AI/AN MSM (N = 173) from a national cross-sectional survey were analyzed.Results: Reporting more frequent sexual risk cognitions overall (high sexual risk cognitions) was associated with multiple HIV risk factors including unprotected anal intercourse and serodiscordant unprotected anal intercourse. Participants with high sexual risk cognitions had a 2.3 (95% Confidence Interval: 1.1, 4.7) times greater odds of engaging in unprotected anal intercourse regardless of childhood sexual abuse, depression, and alcohol dependence. Most individual sexual risk cognitions were associated with unprotected anal intercourse, serodiscordant unprotected anal intercourse, or both.Conclusions: Results suggest that sexual risk cognitions may be a productive area for further work on HIV prevention among AI/AN MSM. [ABSTRACT FROM AUTHOR]

Mathematical models are increasingly used in social and behavioral studies of HIV transmission; however, model structures must be chosen carefully to best answer the question at hand and conclusions must be interpreted cautiously. In Pearson et al. (2007), we presented a simple analytically tractable deterministic model to estimate the number of secondary HIV infections stemming from a population of HIV-positive Mozambicans and to evaluate how the estimate would change under different treatment and behavioral scenarios. In a subsequent application of the model with a different data set, we observed that the model produced an unduly conservative estimate of the number of new HIV-1 infections. In this brief report, our first aim is to describe a revision of the model to correct for this underestimation. Specifically, we recommend adjusting the population-level sexually transmitted infection (STI) parameters to be applicable to the individual-level model specification by accounting for the proportion of individuals uninfected with an STI. In applying the revised model to the original data, we noted an estimated 40 infections/1000 HIV-positive persons per year (versus the original 23 infections/1000 HIV-positive persons per year). In addition, the revised model estimated that highly active antiretroviral therapy (HAART) along with syphilis and herpes simplex virus type 2 (HSV-2) treatments combined could reduce HIV-1 transmission by 72% (versus 86% according to the original model). The second aim of this report is to discuss the advantages and disadvantages of mathematical models in the field and the implications of model interpretation. We caution that simple models should be used for heuristic purposes only. Since these models do not account for heterogeneity in the population and significantly simplify HIV transmission dynamics, they should be used to describe general characteristics of the epidemic and demonstrate the importance or sensitivity of parameters in the model. [ABSTRACT FROM AUTHOR]

The persistence of extreme suicide disparities in American Indian and Alaska Native (AI/AN) youth signals a severe health inequity with distinct associations to a colonial experience of historical and on-going cultural, social, economic, and political oppression. To address this complex issue, we describe three AI/AN suicide prevention efforts that illustrate how strengths-based community interventions across the prevention spectrum can buffer suicide risk factors associated with structural racism. Developed and implemented in collaboration with tribal partners using participatory methods, the strategies include universal, selective, and indicated prevention elements. Their aim is to enhance systems within communities, institutions, and families by emphasizing supportive relationships, cultural values and practices, and community priorities and preferences. These efforts deploy collaborative, local approaches, that center on the importance of tribal sovereignty and self-determination, disrupting the unequal power distribution inherent in mainstream approaches to suicide prevention. The examples emphasize the centrality of Indigenous intellectual traditions in the co-creation of healthy developmental pathways for AI/AN young people. A central component across all three programs is a deep commitment to an interdependent or collective orientation, in contrast to an individual-based mental health suicide prevention model. This commitment offers novel directions for the entire field of suicide prevention and responds to calls for multilevel, community-driven public health strategies to address the complexity of suicide. Although our focus is on the social determinants of health in AI/AN communities, strategies to address the structural violence of racism as a risk factor in suicide have broad implications for all suicide prevention programming.

Abstract: Research regarding the impact of racism on stress among young men who have sex with men (YMSM) is sparse. Secondary data were assessed from a 2018-2020 national mHealth prevention trial for YMSM aged 13-18 years (N = 542). Linear regression models examined associations between perceived stress and interpersonal and vicarious racism, adjusting for covariates. Stratified models by race/ethnicity were included. A subanalysis (n = 288) examined associations between nine interpersonal racial discriminatory events and perceived stress. Over 50% of participants experienced racial discrimination. In the multivariable models, exposure to interpersonal (β = 1.43, p-value: .038) and vicarious (β = 1.77, p-value: .008) racism was associated with perceived stress because there were four interpersonal racial discriminatory events. Stratified analysis by race/ethnicity found significant associations between interpersonal and vicarious racism and perceived stress among some racial/ethnic groups. Racial discrimination was common among YMSM, making them susceptible to the possible effects of vicarious and interpersonal racism on stress., (Copyright © 2023 Association of Nurses in AIDS Care.)

The COVID-19 pandemic has disrupted sexual health services among those most vulnerable to HIV acquisition, such as adolescent men who have sex with men (AMSM). We sought to characterize the changes in sexual-risk behaviors, HIV and other STI testing, and pre-exposure prophylaxis (PrEP) use among a longitudinal cohort of AMSM aged 13 to 18 years before and during the COVID-19 pandemic. We observed a significant decline in HIV testing and a marginal decrease in other STI testing since the pandemic began in March 2020. Outreach efforts and innovative remote delivery of sexual health services are needed to support access to healthcare services among AMSM as the pandemic persists., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Aims: Heart failure with preserved ejection fraction (HFpEF) accounts for 50% of all heart failure cases; yet remains poorly understood, diagnosed, and managed, which adds complexity to the carer role. No study to date has investigated the experiences of informal carers of people with HFpEF. The aim of this study was to explore the role and experiences of informal carers of people with HFpEF., Methods and Results: A qualitative study using semi-structured interviews involving carers alone, patients alone, or carer/patient dyads. The interviews were part of a larger programme of research in HFpEF. Participants were recruited from three regions of England. Interviews were recorded, transcribed verbatim, and analysed thematically. Twenty-two interviews were conducted with 38 participants, 17 were informal carers. Three inter-related themes were identified: Theme 1, the complex nature of informal caregiving ('spinning plates'); Theme 2, the barriers to caregiving ('the spinning falters'); and Theme 3, the facilitators of caregiving ('keeping the plates spinning')., Conclusions: Informal carers play an important role in supporting people with HFpEF. The experience of caregiving in HFpEF is similar to that described for Heart Failure with reduced Ejection Fraction, but complicated by challenges of limited information and support specific to HFpEF, and high burden of multi-morbidity. Healthcare providers should assess the needs of informal carers as part of patient care in HFpEF. Carers and patients would benefit from improved information and co-ordinated management of HFpEF and multi-morbidities. Helping carers 'keep the plates spinning' will require innovative approaches and co-ordination across the care continuum., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Purpose: This study examined factors associated with past-year health care utilization among young gay, bisexual, and other men who have sex with men (YMSM) using Andersen's behavioral model of health service use. Methods: From 2018 to 2020, 751 YMSM (aged 13-18) recruited online and offline for the MyPEEPS mHealth HIV prevention study completed an online survey. Hierarchical logistic regression models assessed associations between past-year health care utilization (i.e., routine checkup) and predisposing (parental education, race/ethnicity, age, and internalized homonegativity), enabling (health literacy, health care facility type, U.S. Census Divisions), and need factors (ever testing for HIV). Results: The sample included 31.8% Hispanic, 23.9% White, and 14.6% Black YMSM; median age was 16. Most (75%) reported past-year health care utilization, often from private doctor's offices (29.1%); 6% reported no regular source of care. In the final regression model, higher odds of past-year health care utilization were found for younger participants (age 13-14, adjusted odds ratio [AOR] = 1.91; 95% confidence interval [CI]: 1.07-3.43; age 15-16 AOR = 1.55; 95% CI: 1.04-2.30; reference: 17-18) and those with increasing health literacy (AOR = 1.71; 95% CI: 1.36-2.16). YMSM with lower parental education had lower odds of past-year health care utilization (AOR = 0.56; 95% CI: 0.38-0.84), as did those relying on urgent care facilities (AOR = 0.60; 95% CI: 0.41-0.87; reference: routine care facilities) and those who identified as Mixed/Other race (AOR = 0.50; 95% CI: 0.28-0.91; reference: White). Conclusions: Findings highlight opportunities to intervene in YMSM's health risk trajectory before age 17 to reduce drop-off in routine health care utilization. Interventions to improve routine health care utilization among YMSM may be strengthened by building resilience (e.g., health literacy) while removing barriers maintained through structural disadvantage, including equity in education. Clinical Trial Registration Number: NCT03167606.

Toxoplasma gondii is an intracellular parasite that generates amylopectin granules (AGs), a polysaccharide associated with bradyzoites that define chronic T. gondii infection. AGs are postulated to act as an essential energy storage molecule that enable bradyzoite persistence, transmission, and reactivation. Importantly, reactivation can result in the life-threatening symptoms of toxoplasmosis. T. gondii encodes glucan dikinase and glucan phosphatase enzymes that are homologous to the plant and animal enzymes involved in reversible glucan phosphorylation and which are required for efficient polysaccharide degradation and utilization. However, the structural determinants that regulate reversible glucan phosphorylation in T. gondii are unclear. Herein, we define key functional aspects of the T. gondii glucan phosphatase TgLaforin (TGME49_205290). We demonstrate that TgLaforin possesses an atypical split carbohydrate-binding-module domain. AlphaFold2 modeling combined with hydrogen-deuterium exchange mass spectrometry and differential scanning fluorimetry also demonstrate the unique structural dynamics of TgLaforin with regard to glucan binding. Moreover, we show that TgLaforin forms a dual specificity phosphatase domain-mediated dimer. Finally, the distinct properties of the glucan phosphatase catalytic domain were exploited to identify a small molecule inhibitor of TgLaforin catalytic activity. Together, these studies define a distinct mechanism of TgLaforin activity, opening up a new avenue of T. gondii bradyzoite biology as a therapeutic target., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

This article examined the psychometric properties and validity of a new self-report instrument for assessing the social norms that coordinate social relations and define self-worth within three normative systems. A survey that assesses endorsement of honor, face, and dignity norms was evaluated in ethnically diverse adolescent samples in the U.S. (Study 1a) and Canada (Study 2). The internal structure of the survey was consistent with the conceptual framework, but only the honor and face scales were reliable. Honor endorsement was linked to self-reported retaliation, less conciliatory behavior, and high perceived threat. Face endorsement was related to anger suppression, more conciliatory behavior, and, in the U.S., low perceived threat. Study 1b examined identity-relevant emotions and appraisals experienced after retaliation and after calming a victimized peer. Honor norm endorsement predicted pride following revenge, while face endorsement predicted high shame. Adolescents who endorsed honor norms thought that only avenging their peer had been helpful and consistent with the role of good friend, while those who endorsed face norms thought only calming a victimized peer was helpful and indicative of a good friend. Implications for adolescent welfare are discussed.

Community-based participatory research (CBPR) has been embraced by diverse populations to address health inequities within their communities. CBPR has been shown to produce favorable health outcomes, but little is known about personal outcomes (e.g., individual growth and capacities) resulting from the direct involvement in a CBPR partnership. We empirically examine which CBPR partnerships' processes and practices are associated with personal outcomes. We hypothesize that higher levels of collaborative approaches and adherence to CBPR principles and practices would be associated with personal outcomes. Based on a national cross-site CBPR study, Research for Improved Health, we utilized mixed-method data from a comprehensive community-engagement survey (N = 450) and seven in-depth case studies to explore the hypothesized relationships. Our multivariate mixed-effects model revealed the importance of various partnering practices. Relationship dynamics emerged as key predictors including the following: respect in the partnership, voice and influence in decision-making among partners, and stewardship. Qualitative findings highlighted individual, partnership, and community-level impacts, within and beyond the partnership. Our findings have implications for CBPR best practices and highlight the potential role of personal outcomes for partnerships' sustainability, long-term outcomes, and health equity research., (© 2020 Society for Community Research and Action.)

African American, European American, Mexican American, and Native American adolescents (N = 270) described how they felt and appraised their own actions in response to a peer's victimization. Analyses compared times they had calmed victim emotions, amplified anger, avenged, and resolved conflicts peacefully. Adolescents felt prouder, more helpful, more like a good friend, and expected more peer approval after calming and resolving than after amplifying anger or avenging peers. They also felt less guilt and shame after calming and resolving. Avenging elicited more positive self-evaluation than amplifying. Epistemic network analyses explored links between self-evaluative and other emotions. Pride was linked to relief after efforts to calm or resolve. Third-party revenge reflected its antisocial and prosocial nature with connections between pride, relief, anger, and guilt., (© 2020 Society for Research on Adolescence.)

Membrane bound acyltransferase-3 (AT3) domain-containing proteins are implicated in a wide range of carbohydrate O-acyl modifications, but their mechanism of action is largely unknown. O-antigen acetylation by AT3 domain-containing acetyltransferases of Salmonella spp. can generate a specific immune response upon infection and can influence bacteriophage interactions. This study integrates in situ and in vitro functional analyses of two of these proteins, OafA and OafB (formerly F2GtrC), which display an "AT3-SGNH fused" domain architecture, where an integral membrane AT3 domain is fused to an extracytoplasmic SGNH domain. An in silico -inspired mutagenesis approach of the AT3 domain identified seven residues which are fundamental for the mechanism of action of OafA, with a particularly conserved motif in TMH1 indicating a potential acyl donor interaction site. Genetic and in vitro evidence demonstrate that the SGNH domain is both necessary and sufficient for lipopolysaccharide acetylation. The structure of the periplasmic SGNH domain of OafB identified features not previously reported for SGNH proteins. In particular, the periplasmic portion of the interdomain linking region is structured. Significantly, this region constrains acceptor substrate specificity, apparently by limiting access to the active site. Coevolution analysis of the two domains suggests possible interdomain interactions. Combining these data, we propose a refined model of the AT3-SGNH proteins, with structurally constrained orientations of the two domains. These findings enhance our understanding of how cells can transfer acyl groups from the cytoplasm to specific extracellular carbohydrates. IMPORTANCE Acyltransferase-3 (AT3) domain-containing membrane proteins are involved in O -acetylation of a diverse range of carbohydrates across all domains of life. In bacteria they are essential in processes including symbiosis, resistance to antimicrobials, and biosynthesis of antibiotics. Their mechanism of action, however, is poorly characterized. We analyzed two acetyltransferases as models for this important family of membrane proteins, which modify carbohydrates on the surface of the pathogen Salmonella enterica , affecting immunogenicity, virulence, and bacteriophage resistance. We show that when these AT3 domains are fused to a periplasmic partner domain, both domains are required for substrate acetylation. The data show conserved elements in the AT3 domain and unique structural features of the periplasmic domain. Our data provide a working model to probe the mechanism and function of the diverse and important members of the widespread AT3 protein family, which are required for biologically significant modifications of cell-surface carbohydrates., (Copyright © 2020 Pearson et al.)

Native Americans (NA) experience interrelated risks of trauma exposure, substance use, and HIV risk behaviors that put them at increased risk for HIV infection. Despite these known risk factors, there are very few published randomized trials testing interventions to reduce trauma-related symptoms and substance misuse among NA., Methods: The Healing Seasons study is a randomized comparsion trial of two counseling strategies, Narrative Exposure Therapy (NET) addressing PTSD or Motivational interviewing with cognitive behavioral therapy skills training (MIST) addressing substance misuse as a means to prevent HIV among NA. Using a community-based participatory research approach, we adapted both evidence-based interventions to be specific to the risk contexts and realities of NA and to include psychoeducational and skill-building components that include cultural-specific stories, virtues, and traditional treatment strategies. Participants, 16 years and older, were recruited from a Pacific Northwest tribal community, screened over the phone, enrolled in person, and randomized in equal numbers to NET or MIST. We stratified by age (16-29 years and 30 or older) and gender (male or female identified) to ensure balance between treatment arms. The primary outcomes were number of sex partners and frequency of sexual acts (with and without condoms), sex under the influence of substances, frequency of substance use, and PTSD severity., Discussion: Behavioral interventions for NA are needed to prevent HIV risk behaviors when faced with trauma symptoms and substance misuse. This study will provide evidence to determine feasibility and efficacy of addressing related risk factors as part of counseling-based HIV prevention intervention to reduce sexual risk among this population., Trial Registration: ClinicalTrials.gov number, NCT03112369, registered April 12, 2017., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Community-based participatory research (CBPR) has captured public health attention and support because it is positioned as an approach that involves researchers and communities as equitable partners in addressing health disparities. However, it is unknown the extent to which CBPR creates a participatory space in the scientific discourse to signal "community voice," which we define as textual expression of community-centered perspectives on collective roles, interests, and worldviews. In this study, we utilized the culture-centered approach to examine the expression of community voice in the abstracts and public health relevance statements of 253 extramural CBPR projects in the U.S. that received funding from the National Institute of Health and Centers for Disease Control and Prevention in 2009. We found that project abstracts and public health relevance statements contain four textual domains, or potential sites of contest to signal the articulation of community agency and voice within the CBPR projects. These domains include: 1) the rationale for the community health issue, 2) the roles of community partners, 3) community-centered outcomes of the partnership, and 4) elements of participatory research process. The degree of culture-centeredness of the texts is suggested in the extent to which articulations of community agency and voice are signaled across the four domains. We conclude that the dynamics of CBPR may shape culture-centered expressions of problem identification, solution configuration, structural transformations, reflexivity, values, and agency in the project abstracts and public health relevance statements.

An overlooked sequela of HIV risk is trauma exposure, yet few HIV interventions address trauma exposure, mental health, and substance misuse. In a two-arm randomized controlled trial 73 Native American women were randomized to a culturally-adapted Cognitive Processing Therapy (CPT) or 6-weeks waitlist. Outcomes assessed: PTSD symptom severity, alcohol use frequency, substance abuse or dependence diagnosis, and high-risk sexual behavior defined as vaginal/anal intercourse (a) under the influence of alcohol and/or illicit substances, (b) with a partner who was concurrently sexually active with someone else, and/or (c) with more than one partner in the past 6 weeks. Among immediate intervention participants, compared to waitlist participants, there were large reductions in PTSD symptom severity, high-risk sexual behavior, and a medium-to-large reduction in the frequency of alcohol use. CPT appears to improve mental health and risk behaviors, suggesting that addressing PTSD may be one way of improving HIV-risk related outcomes.

Objectives: To describe our partnership and research infrastructure development strategies and discuss steps in developing a culturally grounded framework to obtain data and identify a trauma-informed evidence-based intervention., Method: We present funding strategies that develop and maintain the partnership and tools that guided research development. We share how a community research committee was formed and the steps taken to clarify the health concern and develop a culturally tailored framework. We present results from our needs/assets assessment that led to the selection of a trauma-informed intervention. Finally, we describe the agreements and protocols developed., Results: We produced a strong sustainable research team that brought program and research funding to the community. We created a framework and matrix of program objectives grounded in community knowledge. We produced preliminary data and research and publication guidelines that have facilitated program and research funding to address community-driven concerns., Conclusions: This study highlights the importance of bidirectional collaboration with American Indian communities, as well as the time and funding needed to maintain these relationships. A long-term approach is necessary to build a sustainable research infrastructure. Developing effective and efficient ways to build culturally based community research portfolios provides a critical step toward improving individual and community health outcomes.

The primary aim of this study was to develop an American Indian and Alaska Native (AIAN) tailored research with human subjects curriculum that would increase the participation of AIAN members in research affecting their communities. We used a community-engaged research approach to co-design and evaluate a culturally tailored online human subjects curriculum among a national sample of AIAN community members ( n = 244) with a standard nationally used online curriculum ( n = 246). We evaluated pre-and post-test measures to assess group differences in ethics knowledge, perceived self-efficacy to apply such knowledge to protocol review, and trust in research. Analysis of regional tribal differences assessed curriculum generalizability. Using an 80% correct item cut-off at first attempt as passing criterion, the tailored curriculum achieved a 59.3% passing rate versus 28.1% in the standard curriculum ( p < .001). For both arms, participants reported a significant increase in trust in research and in research review efficacy. Participants took less time to complete the training and reported significantly higher acceptability, satisfaction, and understandability of the curriculum for the tailored curriculum. This culturally tailored research ethics curriculum has the potential to increase participation in AIAN communities in research affecting tribal members. The AIAN curriculum achieved significantly higher levels of participants' research ethics knowledge, self-efficacy in reviewing research protocols, trust in research, and completion of the training requirements. Culturally grounded training curricula may help remedy the impact of historical research ethics abuses involving AIAN communities that have contributed to mistrust of research and lack of community engagement in research., Competing Interests: Disclosure statement The authors report no conflicts of interest.

The majority of literature on mentoring focuses on mentee training needs, with significantly less guidance for the mentors. Moreover, many mentoring the mentor models assume generic (i.e. White) mentees with little attention to the concerns of underrepresented racial/ethnic minorities (UREM). This has led to calls for increased attention to diversity in research training programs, especially in the field of HIV where racial/ethnic disparities are striking. Diversity training tends to address the mentees' cultural competency in conducting research with diverse populations, and often neglects the training needs of mentors in working with diverse mentees. In this article, we critique the framing of diversity as the problem (rather than the lack of mentor consciousness and skills), highlight the need to extend mentor training beyond aspirations of cultural competency toward cultural humility and cultural safety, and consider challenges to effective mentoring of UREM, both for White and UREM mentors.

Introduction: Noise-induced hearing loss is a significant cause of morbidity among serving soldiers despite provision of a range of personal hearing protection (PHP) and education and training. It appears that soldiers are choosing to forego PHP. This audit aimed to evaluate the effect of health promotion activity on the use of hearing protection in hostile territory., Method: 46 dismounted infantry soldiers operating out of a forward operating base in Afghanistan during Op HERRICK 17 were directly observed in order to determine the rate of wearing PHP before and after health promotion activity., Results: In the initial phase, 39% of soldiers (range 16-74%) wore PHP in at least one ear, but following health promotion activity the rate fell to 12% (range 9-14%)., Conclusions: The reduction in the wearing of PHP appears to have been because the perceived diminished threat of enemy contact was outweighed by any benefit of health promotion activity. Reasons for poor compliance were not investigated, but it appears that behavioural factors, and specifically, leadership at the smallest unit level, are important. These should be investigated and considered in the development of future PHP., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Background: Although there is strong scientific, policy, and community support for community-engaged research (CEnR)-including community-based participatory research (CBPR)-the science of CEnR is still developing., Objective: To describe structural differences in federally funded CEnR projects by type of research (i.e., descriptive, intervention, or dissemination/policy change) and race/ethnicity of the population served., Methods: We identified 333 federally funded projects in 2009 that potentially involved CEnR, 294 principal investigators/project directors (PI/PD) were eligible to participate in a key informant (KI) survey from late 2011 to early 2012 that asked about partnership structure (68% response rate)., Results: The National Institute on Minority Health & Health Disparities (19.1%), National Cancer Institute (NCI; 13.3%), and the Centers for Disease Control and Prevention (CDC; 12.6%) funded the most CEnR projects. Most were intervention projects (66.0%). Projects serving American Indian or Alaskan Native (AIAN) populations (compared with other community of color or multiple-race/unspecified) were likely to be descriptive projects (p<.01), receive less funding (p<.05), and have higher rates of written partnership agreements (p<.05), research integrity training (p<.05), approval of publications (p<.01), and data ownership (p<.01). AIAN-serving projects also reported similar rates of research productivity and greater levels of resource sharing compared with those serving multiple-race/unspecified groups., Conclusions: There is clear variability in the structure of CEnR projects with future research needed to determine the impact of this variability on partnering processes and outcomes. In addition, projects in AIAN communities receive lower levels of funding yet still have comparable research productivity to those projects in other racial/ethnic communities.

We assessed the relationship between post-traumatic stress disorder (PTSD), binge drinking, and HIV sexual risk behavior by examining number of unprotected sex acts and number of sexual partners in the past 6 months among 129 sexually active American Indian women. A total of 51 (39.5%) young women met PTSD criteria. Among women who met the PTSD criteria, binge drinking was associated with a 35% increased rate of unprotected sex (IRR 1.35, p < .05), and there was a stronger association between increased binge drinking and risk of more sexual partners (IRR 1.21, p < .001) than among women who did not meet PTSD criteria (IRR 1.08, p < .01) with a difference of 13% (p < .05). HIV intervention and prevention interventions in this population likely would benefit from the inclusion of efforts to reduce binge drinking and increase treatment of PTSD symptoms.

This study examined associations between alcohol misuse and childhood maltreatment and out-of-home placement among urban lesbian, gay, and bisexual (referred to as two-spirit) American Indian and Alaska Native adults. In a multi-site study, data were obtained from 294 individuals who consumed alcohol during the past year. The results indicated that 72.3% of men and 62.4% of women engaged in hazardous and harmful alcohol use and 50.8% of men and 48.7% of women met criteria for past-year alcohol dependence. The most common types of childhood maltreatment were physical abuse among male drinkers (62.7%) and emotional abuse (71.8%) among female drinkers. Men and women reported high percentages of out-of-home placement (39% and 47%, respectively). Logistic multiple regressions found that for male drinkers boarding school attendance and foster care placement were significant predictors of past-year alcohol dependence. For female drinkers, being adopted was significantly associated with a decreased risk of past-year drinking binge or spree. Dose-response relationships, using number of childhood exposures as a predictor, were not significant. The results highlight the need for alcohol and violence prevention and intervention strategies among urban two-spirit individuals.

Lumpy skin disease is of significant economic impact for the cattle industry in Africa. The disease is currently spreading aggressively in the Near East, posing a threat of incursion to Europe and Asia. Due to cross-protection within the Capripoxvirus genus, sheep pox virus (SPPV) vaccines have been widely used for cattle against lumpy skin disease virus (LSDV). In the Middle East and the Horn of Africa these vaccines have been associated with incomplete protection and adverse reactions in cattle post-vaccination. The present study confirms that the real identity of the commonly used Kenyan sheep and goat pox vaccine virus (KSGP) O-240 is not SPPV but is actually LSDV. The low level attenuation of this virus is likely to be not sufficient for safe use in cattle, causing clinical disease in vaccinated animals. In addition, Isiolo and Kedong goat pox strains, capable of infecting sheep, goats and cattle are identified for potential use as broad-spectrum vaccine candidates against all capripox diseases., (Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.)

Multiple challenges expose American Indian and Alaska Native (AIAN) women to high-risk sexual partnerships and increased risk for HIV/STI. Using a unique sample of sexually-active young AIAN women (n = 129), we examined characteristics of last three partners and whether transitional partnerships were associated with different risk profiles, including where partners met, lived, and had sex. Respondents were more likely to have met their previous or current secondary partner (P2) at a friend's or family setting (versus work or social setting) (AOR = 3.92; 95 % CI 1.31, 11.70). Condom use was less likely when meeting a partner at friend's or family settings (AOR = 0.17; 95 % CI 0.05, 0.59). Sexual intercourse with P2 (compared to P1) usually took place in "riskier" settings such as a car, bar, or outside (AOR = 4.15; 95 % CI 1.59, 10.68). Perceived "safe" places, e.g., friend's or family's house, were identified with risky behaviors; thus, homogeneous messaging campaigns may promote a false sense of safety.

Current human subject research training modules fail to capture ethically relevant cultural aspects of research involving American Indian and Alaska Native (AI/AN) community members. Applying a Community Engaged Research (CEnR) approach, we adapted the Collaborative IRB Training Initiative training module "assessing risk and benefits." In a two-arm randomized controlled trial, followed by debriefing interviews, we evaluated module acceptability and understandability (test scores) among 40 reservation-based community members. Participants who took the adapted module, compared to those who took the standard module, reported higher scores on relevance of the material overall satisfaction, module quiz scores, and a trend toward higher self-efficacy. Implications of the efficacy of this approach for enhancing ethics training and community participation in research within AI/AN and other cultural populations within and outside the United States are discussed.

Contemporary HIV prevention efforts are increasingly focused on those already living with HIV/AIDS (i.e., "prevention with positives"). Key to these initiatives is research identifying the most risky behavioral targets. Using a longitudinal design, we examined socio-demographic and psychosocial factors that prospectively predicted unprotected anal intercourse (UAI) in a sample of 134 HIV-seropositive men who have sex with men (MSM) initiating, changing, or re-starting an antiretroviral therapy regimen as part of a behavioral intervention study. Computer-based questionnaires were given at baseline and 6 months. In a sequential logistic regression, baseline measures of UAI (step 1), socio-demographic factors such as Latino ethnicity (step 2), and psychosocial factors such as crystal methamphetamine use, greater life stress, and lower trait anxiety (step 3) were predictors of UAI at 6 months. Problem drinking was not a significant predictor. Prevention efforts among MSM living with HIV/AIDS might focus on multiple psychosocial targets, like decreasing their crystal methamphetamine use and teaching coping skills to deal with life stress.

American Indian and Alaska Native (AIAN) men who have sex with men (MSM) are considered particularly high risk for HIV transmission and acquisition. In a multi-site cross-sectional survey, 174 AIAN men reported having sex with a man in the past 12 months. We describe harm reduction strategies and sexual behavior by HIV serostatus and seroconcordant partnerships. About half (51.3%) of the respondents reported no anal sex or 100% condom use and 8% were in seroconcordant monogamous partnership. Of the 65 men who reported any sero-adaptive strategy (e.g., 100% seroconcordant partnership, strategic positioning or engaging in any strategy half or most of the time), only 35 (54.7%) disclosed their serostatus to their partners and 27 (41.5%) tested for HIV in the past 3 months. Public health messages directed towards AIAN MSM should continue to encourage risk reduction practices, including condom use and sero-adaptive behaviors. However, messages should emphasize the importance of HIV testing and HIV serostatus disclosure when relying solely on sero-adaptive practices.

Background: Systematic efforts of assimilation removed many Native children from their tribal communities and placed in non-Indian-run residential schools., Objectives: To explore substance use and mental health concerns among a community-based sample of 447 urban two-spirit American Indian/Alaska Native adults who had attended boarding school as children and/or who were raised by someone who attended boarding school., Method: Eighty-two respondents who had attended Indian boarding school as children were compared to respondents with no history of boarding school with respect to mental health and substance use., Results: Former boarding school attendees reported higher rates of current illicit drug use and living with alcohol use disorder, and were significantly more likely to have attempted suicide and experienced suicidal thoughts in their lifetime compared to non-attendees. About 39% of the sample had been raised by someone who attended boarding school. People raised by boarding school attendees were significantly more likely to have a general anxiety disorder, experience posttraumatic stress disorder symptoms, and have suicidal thoughts in their lifetime compared to others.

Stigma towards people living with HIV is pervasive in China and related to poor service utilization, psychosocial distress and diminished quality of life (QOL). In an effort to identify mechanisms to reduce HIV stigma and its negative consequences, we examined whether social support mediates the relation between enacted stigma and both depressive symptoms and QOL among 120 HIV outpatients in Beijing, China. Generally, perceived social support was associated with less stigma, less depressive symptomatology and better QOL. Using multivariable regression models, we found that social support was a full mediator of the impact of stigma on both depressive symptomatology and QOL. The findings suggest social support may be an important target of interventions to reduce the impact of stigma on poor psychosocial health outcomes.

We assessed sexual behaviors before and 12-months after ART initiation among 277 Mozambicans attending an HIV clinic. Measured behaviors included the number of sexual partners, condom use, concurrent relationships, disclosure of HIV status, alcohol use, and partners' serostatus. Compared to before ART initiation, increases were seen 12 months after ART in the proportion of participants who were sexually active (48% vs. 64% respondents, P < 0.001) and the proportion of participants with HIV-negative or unknown serostatus partners (45% vs. 80%, P < 0.001). Almost all (96%) concurrent partnerships reported at 12 months formed after ART initiation. Although reported correct and consist condom use increased, the number of unprotected sexual relationships remained the same (n = 45). Non-disclosure of HIV-serostatus to sexual partners was the only significant predictor of practicing unprotected sex with partners of HIV-negative or unknown serostatus. Sexual activity among HIV-positive persons on ART increased 12 months after ART initiation. Ongoing secondary transmission prevention programs addressing sexual activity with multiple partners, disclosure to partners and consistent condom use with serodisconcordant partners must be incorporated throughout HIV care programs.

Objectives: To describe the pattern of ear injuries sustained by all British servicemen serving in Iraq and Afghanistan between 2006 and 2009; to identify all servicemen evacuated to the Royal Centre for Defence Medicine following blast injury; to ascertain how many underwent otological assessment; and to calculate the incidence of hearing loss., Design and Setting: A retrospective analysis of data obtained from the Joint Theatre Trauma Registry and the Defence Analytical and Statistics Agency, together with audiometry records from the University Hospitals Birmingham National Health Service Trust., Results: Ear damage was present in 5 per cent of all British servicemen sustaining battle injuries. Tympanic membrane rupture occurred in 8 per cent of personnel evacuated with blast injuries. In 2006, 1 per cent of servicemen sustaining blast injury underwent audiography; this figure rose to 13 per cent in 2009. Fifty-three per cent of these audiograms were abnormal., Conclusion: The incidence of tympanic membrane rupture was higher than that found in previous conflicts. Otological assessment prior to and following military deployment is required to determine the incidence of ear injury amongst British servicemen following blast trauma.

Objectives: Risk factors for human immunodeficiency virus (HIV) disease progression among American Indians (AIs) have been poorly characterized. We assessed the impact of socioeconomic factors and use of traditional healing on HIV disease progression in a rural AI community., Methods: From January 2004 through December 2006, we interviewed 36 HIV-positive AIs regarding their socioeconomic status, incarceration, and use of traditional healing. We also collected chart-abstracted adherence and substance-abuse data. Through bivariate analysis, we compared these factors with the CD4-cell counts and log HIV-1 viral loads (VLs). Using a simple regression model, we assessed interactions between the significant associations and the outcome., Results: Participant characteristics included being male (58.3%), being transgender (13.9%), having ever been incarcerated (63.9%), having a household income of < $1,000/month (41.7%), being unemployed (61.1%), being diagnosed with alcohol abuse (50.0%), and using traditional medicine (27.8%) in the last 12 months. Higher VLs were associated with recent incarceration (p < 0.05), household income of < $1,000/month (p < 0.05), and provider-assessed alcohol abuse (p < 0.05). We found an interaction between incarceration and alcohol abuse, and alcohol abuse was the factor more strongly associated with higher VLs. A lower CD4 count was associated with recent incarceration (p < 0.05) and use of traditional medicine (p < 0.05)., Conclusions: Alcohol abuse is an important contributor to HIV disease progression, and participants with lower CD4 counts were more likely to use traditional medicine. HIV care among this rural AI population should focus on addressing alcohol abuse and other socioeconomic risk factors and promote collaboration between Western medical and Navajo traditional practitioners.

Background: American Indian and Alaska Natives suffer pervasive health disparities, including disproportionately high rates of HIV. Sexual network dynamics, including concurrency and sexual mixing patterns, are key determinants of HIV disparities., Methods: We analyzed data from the first national study of gay, lesbian, bisexual, and transgender American Indian and Alaska Natives to examine the prevalence of concurrency, sex and race of partners, and level of risk across different partnership patterns. Egocentric network data were analyzed at the level of the respondents, who were grouped according to the sex of their last 3 partners., Results: Overall rates of HIV and concurrency were high in this population. HIV prevalence (34%) and cumulative prevalence of concurrency (55%) were highest among men who had sex with only men, while women who had sex with only women reported lower concurrency and HIV. Women who had sex with women and men also had high HIV prevalence (15%) and reported slightly higher concurrency risk and low condom use, making them effective bridge populations., Conclusions: The uniformly high rates of Native partner selection creates the potential for amplification of disease spread within this small community, while the high rates of selecting partners of other races creates the potential for bridging to other groups in the transmission network. These findings provide some of the first insights into sexual networks and concurrency among Native gay, lesbian, bisexual, and transgender populations and suggest that both men and women deserve attention in HIV prevention efforts at individual, dyadic and population levels.

Objective: To determine the relative efficacy of peer support and pager messaging strategies versus usual care to improve medication adherence and clinical outcomes among HIV-positive outpatients initiating or switching to a new highly active antiretroviral therapy regimen., Design: A 2 3 2 factorial randomized controlled trial of a 3-month intervention with computer-assisted self-interviews and blood draws administered at baseline, 3, 6, and 9 months., Methods: HIV-positive patients at a public HIV specialty clinic in Seattle,WA (N = 224) were randomly assigned to peer support, pager messaging, both strategies, or usual care. The main outcomes were adherence according to self-report and electronic drug monitoring, CD4 count, and HIV-1 RNA viral load., Results: Intent-to-treat analyses suggested the peer intervention was associated with greater self-reported adherence at immediate postintervention. However, these effects were not maintained at follow-up assessment; nor were there significant differences in biological outcomes. The pager intervention, on the other hand, was not associated with greater adherence but was associated with improved biological outcomes at postintervention that were sustained at follow-up., Conclusions: Analyses indicate the potential efficacy of peer support and pager messaging to promote antiretroviral adherence and biological outcomes, respectively. More potent strategies still are needed.

The pathways through which stigma is associated with psychological distress remains understudied in Africa. This study evaluates stigma among 277 Mozambicans who were on an antiretroviral therapy (ART) regimens for a full year. Using bivariate and multiple regression analyses, we examine psychosocial factors (disclosure decisions, perceived social support, and depression) associated with stigma, at ART initiation and 1 year later. We found 1 year after initiating ART, participants reported no change in stigma, a decrease in perceived social support, and an increase in depressive symptomology. Disclosing HIV status to friends (versus family or partner) was associated with lower levels of stigma. These findings suggest that HIV care in comparable settings should include counselling, support groups, and peer support, that includes stigma and disclosure concerns prior to and during the first year following diagnosis. Most importantly, assessment and treatment of depression should be incorporated into ongoing HIV care.

The success of antiretroviral therapy (ART) for HIV infection, though widespread and resounding, has been limited by inadequate adherence to its unforgiving regimens, especially over the long term. This article summarizes the literature on behavioral interventions to promote ART adherence and highlights some of the most recent and innovative research on patient education and case management, modified directly observed therapy, contingency management, interventions emphasizing social support, and novel technologies to promote awareness. Research in the area of adherence in pediatric HIV infection and in resource-constrained international settings also is considered. Although adherence interventions have been successful in experimental trials, they may not be feasible or adaptable given the constraints of real-world clinics and community-based settings. Implementation and dissemination of adherence interventions needs increased attention as ART adherence research moves beyond its first decade. We conclude with suggestions for incorporating research findings into clinical practice.

Halogenated disinfection byproducts (DBPs) may undergo reduction reactions at the corroded pipe wall in drinking water distribution systems consisting of cast or ductile iron pipe. Iron pipe corrosion products were obtained from several locations within two drinking water distribution systems. Crystalline-phase composition of freeze-dried corrosion solids was analyzed using X-ray diffraction, and ferrous and ferric iron contents were determined via multiple extraction methods. Batch experiments demonstrated that trichloronitromethane (TCNM), a non-regulated DBP, is rapidly reduced in the presence of pipe corrosion solids and that dissolved oxygen (DO) slows the reaction. The water-soluble iron content of the pipe solids is the best predictor of TCNM reaction rate constant. These results indicate that highly reactive DBPs that are able to compete with oxygen and residual disinfectant for ferrous iron may be attenuated via abiotic reduction in drinking water distribution systems.

Maximizing our economic investment in HIV prevention requires balancing the costs of candidate interventions against their effects and selecting the most cost-effective interventions for implementation. However, many HIV prevention intervention trials do not collect cost information, and those that do use a variety of cost data collection methods and analysis techniques. Standardized cost data collection procedures, instrumentation, and analysis techniques are needed to facilitate the task of assessing intervention costs and to ensure comparability across intervention trials. This article describes the basic elements of a standardized cost data collection and analysis protocol and outlines a computer-based approach to implementing this protocol. Ultimately, the development of such a protocol would require contributions and "buy-in" from a diverse range of stakeholders, including HIV prevention researchers, cost-effectiveness analysts, community collaborators, public health decision makers, and funding agencies.

Objective: To assess the efficacy of a peer-delivered intervention to promote short-term (6-month) and long-term (12-month) adherence to HAART in a Mozambican clinic population., Design: A 2-arm randomized controlled trial was conducted between October 2004 and June 2006., Participants: Of 350 men and women (> or = 18 years) initiating HAART, 53.7% were female, and 97% were on 1 fixed-dose combination pill twice a day., Intervention: Participants were randomly assigned to receive 6 weeks (Monday through Friday; 30 daily visits) of peer-delivered, modified directly observed therapy (mDOT) or standard care. Peers provided education about treatment and adherence and sought to identify and mitigate adherence barriers., Outcome: Participants' self-reported medication adherence was assessed 6 months and 12 months after starting HAART. Adherence was defined as the proportion of prescribed doses taken over the previous 7 days. Statistical analyses were performed using intention-to-treat (missing = failure)., Results: Intervention participants, compared to those in standard care, showed significantly higher mean medication adherence at 6 months (92.7% vs. 84.9%, difference 7.8, 95% confidence interval [CI]: 0.0.02, 13.0) and 12 months (94.4% vs. 87.7%, difference 6.8, 95% CI: 0.9, 12.9). There were no between-arm differences in chart-abstracted CD4 counts., Conclusions: A peer-delivered mDOT program may be an effective strategy to promote long-term adherence among persons initiating HAART in resource-poor settings.

Understanding sexual behavior and assessing transmission risk among people living with HIV-1 is crucial for effective HIV-1 prevention. We describe sexual behavior among HIV-positive persons initiating highly active antiretroviral therapy (HAART) in Beira, Mozambique. We present a Bernoulli process model (tool available online) to estimate the number of sexual partners who would acquire HIV-1 as a consequence of sexual contact with study participants within the prior three months. Baseline data were collected on 350 HAART-naive individuals 18-70 years of age from October 2004 to February 2005. In the three months prior to initiating HAART, 45% (n = 157) of participants had sexual relationships with 191 partners. Unprotected sex occurred in 70% of partnerships, with evidence suggesting unprotected sex was less likely with partners believed to be HIV-negative. Only 26% of the participants disclosed their serostatus to partners with a negative or unknown serostatus. Women were less likely to report concurrent relationships than were men (21 versus 66%; OR 0.13; 95%CI: 0.06, 0.26). Given baseline behaviors, the model estimated 23.2 infections/1,000 HIV-positive persons per year. The model demonstrated HAART along with syphilis and herpes simplex virus type 2 (HSV-2) treatment combined could reduce HIV-1 transmission by 87%; increasing condom use could reduce HIV-1 transmission by 67%.

We explored methodological issues related to antiretroviral adherence assessment, using 6 months of data collected in a completed intervention trial involving 136 low-income HIV-positive outpatients in the Bronx, NY. Findings suggest that operationalizing adherence as a continuous (versus dichotomous) variable and averaging adherence estimates over multiple assessment points (versus using only one) explains greater variance in HIV-1 RNA viral load (VL). Self-reported estimates provided during a phone interview accounted for similar variance in VL as EDM estimates (R (2) = .17 phone versus .18 EDM). Self-reported adherence was not associated with a standard social desirability measure, and no difference in the accuracy of self-report adherence was observed for assessment periods of 1-3 days. Self-reported poor adherence was more closely associated with EDM adherence estimates than self-reported moderate and high adherence. On average across assessment points, fewer than 4% of participants who reported taking a dose of an incorrect amount of medication.

Adherence to highly active antiretroviral therapy (HAART) is generally suboptimal, limiting the effectiveness of HAART. This meta-analytic review examined whether behavioral interventions addressing HAART adherence are successful in increasing the likelihood of a patient attaining 95% adherence or an undetectable HIV-1 RNA viral load (VL). We searched electronic databases from January 1996 to September 2005, consulted with experts in the field, and hand searched reference sections from relevant articles. Nineteen studies (with a total of 1839 participants) met the selection criteria of describing a randomized controlled trial among adults evaluating a behavioral intervention with HAART adherence or VL as an outcome. Random-effects models indicated that across studies, participants in the intervention arm were more likely than those in the control arm to achieve 95% adherence (odds ratio [OR] = 1.50, 95% confidence interval [CI]: 1.16 to 1.94); the effect was nearly significant for undetectable VL (OR = 1.25; 95% CI: 0.99 to 1.59). The intervention effect for 95% adherence was significantly stronger in studies that used recall periods of 2 weeks or 1 month (vs.

As resource-limited countries expand access to highly active antiretroviral therapy (HAART) treatment, innovative programs are needed to support adherence in the context of significant health system barriers. Modified directly observed therapy (mDOT) is one such strategy, but little is known about the process of designing and implementing mDOT programs for HAART in resource-limited settings. In this descriptive study, we used a mixed-methods approach to describe the process of implementing mDOT for an ongoing randomized control trial (RCT) in Beira, Mozambique. Interviews with clinic staff, mDOT peers, and participants provided information on design elements, problems with implementation, satisfaction, and benefits. Acceptability and feasibility measures were obtained from the RCT. Most (81%, N = 350) eligible persons agreed to participate, and of those randomized to mDOT (n = 174), 95% reported that their time with peers was beneficial. On average, participants kept 93% of the 30 required daily mDOT visits. Key components of the intervention's success included using peers who were well accepted by clinic staff, adequate training and retention of peers, adapting daily visit requirements to participants' work schedules and physical conditions, and reimbursing costs of transportation. This study identified aspects of mDOT that are effective and can be adopted by other clinics treating HIV patients.

A review of 77 studies employing self-report measures of antiretroviral adherence published 1/1996 through 8/2004 revealed great variety in adherence assessment item content, format, and response options. Recall periods ranged from 2 to 365 days (mode = 7 days). The most common cutoff for optimal adherence was 100% (21/48 studies, or 44%). In 27 of 34 recall periods (79%), self-reported adherence was associated with adherence as assessed with other indirect measures. Data from 57 of 67 recall periods (84%) indicated self-reported adherence was significantly associated with HIV-1 RNA viral load; in 16 of 26 (62%), it was associated with CD4 count. Clearly, the field would benefit from item standardization and a priori definitions and operationalizations of adherence. We conclude that even brief self-report measures of antiretroviral adherence can be robust, and recommend items and strategies for HIV research and clinical management.

Halonitromethanes (HNMs) are a class of halogenated disinfection byproducts formed upon the addition of chlorine to water containing organic matter. Batch experiments were performed to investigate the reaction pathways and kinetics of three HNMs (chloropicrin or trichloronitromethane [TCNM], dichloronitromethane [DCNM], and chloronitromethane [CNM]) with zero-valent iron (Fe0). All three compounds reacted rapidly in the presence of Fe0 (1.8-4.4 g/L) with methylamine (MA) as the final product. The geometric surface area-normalized rate constants decreased with decreasing halogenation: TCNM (301 L/[h-m2]) > DCNM (153 L/(h-m2)) > CNM (45.9 L/[h-m2]). Nitromethane, an intermediate species, rapidly reacted to form MA (302 L/[h-m2]). These reactions all experienced some degree of mass transfer limitation (9-73%). The average carbon and chlorine mass balances for TCNM were >85%, indicating that the major reaction products were recovered. The degradation of TCNM and DCNM proceeded via the parallel reaction pathways of hydrogenolysis and alpha-elimination. For TCNM, 60.7 +/- 8.7% of reaction proceeded via hydrogenolysis and 39.3 +/- 6.4% via alpha-elimination. Knowledge of HNM reaction pathways and kinetics in the presence of Fe0 may be useful for predicting the fate of these compounds in drinking water distribution systems containing cast or ductile iron pipe and for developing treatment systems for HNM removal from water.

Association of extracellular protein product with flocculated cells reduces product yield. Here, partitioning of the enzyme subtilisin between the liquid and polyelectrolyte-flocculated and sedimented Bacillus increased as the polymer dosage was increased beyond that necessary to obtain optimum floc character (brain floc) for cell removal by centrifugation. Partitioning to the cell floc is partly physical entrapment at all polymer dosages; however, at higher levels there is also direct interaction between the polyelectrolyte and enzyme. Enzyme loss was not likely due to pH denaturation during the flocculation process because conditions were within the stable pH range of the enzyme. The direct interaction between polyelectrolyte and enzyme was characterized through turbidimetric titrations and partitioning studies. Neither changes in the polymer feed concentration nor the method of polymer addition reduced the enzyme loss at dosages optimal for cell removal., (Copyright 2004 Wiley Periodicals, Inc.)

Characterization of flocculation for cell removal from fermentation broth via polyelectrolyte addition is commonly based on qualitative methods such as physical appearance of the floc. The use of zeta potential as a quantitative measure of floc character was evaluated as an indicator of optimal polymer addition. Zeta potential was found to increase with increasing cationic polyelectrolyte dosage, but never reached zero regardless of the total amount of polymer added, indicating flocculation occurs at least partially through a bridging type mechanism. Experiments were conducted using various polymer concentrations (25-75 g/L) and dosing methods (batch, incremental and continuous addition) that resulted in variable overall polymer requirements to achieve optimum flocculation. Zeta potential was found to be constant at optimal floc character regardless of the total amount of polymer added, polymer concentration, or method of polymer addition. Experiments with two additional types of fermentation broth also showed characteristic zeta potentials at optimal flocculation. Polymer requirements to achieve a particular floc character can vary greatly, depending on polymer dosing conditions and fermentation batch. The effect of polymer dosing conditions on the polymer requirement to obtain optimal floc character was evaluated. Polymer dosing method and calcium concentration were both found to have a significant effect (P < 0.0001) with continuous polymer addition and high calcium concentration requiring less polymer than did batch polymer addition and low calcium concentration, respectively. Polymer dosing concentration did not significantly affect polymer requirement for optimal flocculation., (Copyright 2004 Wiley Periodicals, Inc.)