Determination of polar and dispersive contributions of surface tensions of some macromolecular solutions

The determination of the surface tension of some liquids or solutions has been carried out using a tensiometer. The determination of the contact angle between the liquids and a planar surface has also been carried out using photography. Polar and dispersive contributions of the surface tension were obtained by calculation while the polarities of the liquids and solutions were determined applying Wu equations. This method gave the different results for solutions prepared from macromolecular compounds (acroleineethanolamine macromolecular solution 1 g/l, acroleine-diethanolamine macromolecular solution 1 g/l, acroleine-urea macromolecular solution 0.7 g/l and polyglutaraldehyde-ethanolamine macromolecular solution 1 g/) synthesized by Malonda from glutaraldehyde and acroleine. The dispersive and polar contributions of the surface tension were computed and used to calculate the surface tensions of solutions by the simple measurement of the contact angle. The results have revealed that the polarities were weak: 2% for all solutions except for the acroleine-diethanolamine macromolecular whose polarity was 6%. The surface tensions for all solutions varied from 67 to 59 dynes/cm.Keywords: Surface tension, interfacial tension, contact angle, polarity, dispersive and polar contribution

CALCULATION OF INTERFACIAL TENSIONS BETWEEN MACROMOLECULAR SOLUTIONS AND SOLTROL-130 FROM CONTACT ANGLES MEASUREMENTS

ABSTRACT The determination of the surface tension of some liquids or solutions has been carried out using a tensiometer. The determination of the contact angle between the liquids and a planar surface has also been carried out using photography. Polar and dispersive contributions of the surface tension were obtained by calculation while the polarities of the liquids and solutions were determined applying Wu equations. This method gave the different results for solutions prepared from macromolecular compounds (acroleine -ethanolamine macromolecular solution 1g/l, acroleinediethanolamine macromolecular solution 1g/l, polyglutaraldehyde-ethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde -diethanolamine macromolecular solution 1 g/l) synthesized by Malonda from glutaraldehyde and acroleine. The dispersive and polar contributions of the surface tension were computed and used to calculate the interfacial tensions of solutions by the simple measurement of the contact angle. The results have revealed that the computed interfacial tensions were comparable to the values measured directly by the tensiometer for polyglutaraldehydeethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde -diethanolamine macromolecular solution 1 g/l) making an interface with Soltrol-130 of 17.1 and 16.9 dynes/cm compared to direct measured values of 17.2 and 17.7 dynes/cm respectively representing 1% and 5% error, respectively

Size Reduction Of Food Commodities And Food Safety In Some Accra Markets

The objective of this paper is to investigate the food safety and hygienic status after size reduction in some Accra markets, using questionnaire and bacterial samples to validate the questionnaire findings. The primary research was done in the Kaneshie, Makola and Nima markets in Accra. The work involved more than 55 milling machines in these different and affluent markets. The audit form used consisted of a number of questions for each of the 21 respondents chosen at random with a range of one to three machines, some owning up to 5 machines. In addition to the audit, 36 samples of tomatoes were taken before and after milling to assess their microbiological safety and the microbial total load by evaluating the platecount agar (PCA), and Violet Red Bile Glucose (VRBG) for the detection and enumeration of Enterobacteriaceae such as Escherichia coli indicating the presence of potential faecal contamination. All 36 samples from the three markets were relatively microbiologically contaminated. The contamination load increased with the milling time. After size reduction of the foods they came out of the machine more contaminated than they entered. Some foods are subjected to adulteration in the size reduction machine. The results of this study suggest that even though most of the foods are cooked before consumption it is necessary to put in place good manufacturing practice (GMP) which must be followed starting with Hazard Analysis and Critical Control Points (HACCP) principles. If this is not done, consumption of such products could lead to serious health hazards especially where they are not cooked enough to eliminate the microbial loads. Disinfection of the machine and the environment will be necessary after each milling session. The products to be milled should be of better microbial quality as well so that the milled product can be safe for consumption. The enforcing agencies and other stakeholders also have a big role to play in terms of awareness and education for the good of the consumer

The fermentation characteristics of single and mixed yeast cultures during pito wort fermentation

Abstract Pito is an alcoholic beverage obtained through yeast fermentation of the wort extracted from sorghum malt. The production methods are largely artisanal and the product quality varies from batch to batch even for the same brewer. The use of starter culture is a plausible approach to minimizing the variability in product quality. This work compared the fermentation profile of single yeast and mixed yeast cultures in sorghum wort fermentation during pito production. A 2 x 3 factorial design was used to study the quality characteristics of wort pitched with single and mixed Culture yeast strains during 24, 48 and 72 hours alcoholic fermentation. The physicochemical properties, microbial load and sensory characteristics of samples were determined. Fermentation time had significant effects (p<0.05) on the pito characteristics. Pito color (of 12.5 and 16.5 EBC units) was different for single and mixed cultures respectively. Panelists perceived the colours of pito obtained from single yeast culture fermentation to be different from that obtained from mixed culture fermentation. Volatile aroma compounds identified during the fermentation period included esters (4), aldehydes (3), organic acids (2), alcohols (3) and a diacetyl. Both single and mixed cultures showed similar characteristics during wort fermentation

Social contexts as mediator of risk behaviors in Rwandan men who have sex with men (MSM): Implications for HIV and STI transmission.

IntroductionMen who have sex with men (MSM) are disproportionately impacted by HIV/AIDS resulting from risky sexual behaviors. Social and contextual factors are known to mediate risk behaviors, but there is limited information about the prevalence of risky sexual practices of Rwandan MSM and the concomitant socio-contextual determinants making it difficult to assess implications for preventing HIV/STI transmission in this key population.MethodsUsing exploratory qualitative design, we obtained socio-contextual information regarding prevalence of risky sexual behavior and assessed implications for HIV/ STIs transmission and preventive measures taken by MSM to improve sexual health and wellbeing. Thirty MSM were recruited to participate in in-depth interviews using respondent-driven sampling from LGBT associations in Kigali. Data were analyzed using standard qualitative data analysis procedures.ResultsRespondents' were between 18-40 years old; all completed primary education and are mostly low-socioeconomic status. Risky sexual practices were common, but differed by peculiar individual and contextual factors. Older MSM often reported occasional sexual relations with women to avoid suspicion and social stigma. Younger MSM's risky sexual practices are mostly transactional and mediated by the need for social acceptance and support. Knowledge of STIs was poor, but prevalence, especially of HPV was high. The options for improving sexual wellbeing are limited and mostly clandestine.ConclusionRisky sexual behavior of Rwandan MSM has major implications for HIV/STI transmission. An environment of intense social stigma and social isolation makes it difficult to obtain information or services to improve sexual health. Effective interventions that address individual and contextual determinants of risk and access to health services are urgently needed to limit the consequence of MSM as a bridge for HIV transmission to the general population

Social contexts as mediator of risk behaviors in Rwandan men who have sex with men (MSM): Implications for HIV and STI transmission.

IntroductionMen who have sex with men (MSM) are disproportionately impacted by HIV/AIDS resulting from risky sexual behaviors. Social and contextual factors are known to mediate risk behaviors, but there is limited information about the prevalence of risky sexual practices of Rwandan MSM and the concomitant socio-contextual determinants making it difficult to assess implications for preventing HIV/STI transmission in this key population.MethodsUsing exploratory qualitative design, we obtained socio-contextual information regarding prevalence of risky sexual behavior and assessed implications for HIV/ STIs transmission and preventive measures taken by MSM to improve sexual health and wellbeing. Thirty MSM were recruited to participate in in-depth interviews using respondent-driven sampling from LGBT associations in Kigali. Data were analyzed using standard qualitative data analysis procedures.ResultsRespondents' were between 18-40 years old; all completed primary education and are mostly low-socioeconomic status. Risky sexual practices were common, but differed by peculiar individual and contextual factors. Older MSM often reported occasional sexual relations with women to avoid suspicion and social stigma. Younger MSM's risky sexual practices are mostly transactional and mediated by the need for social acceptance and support. Knowledge of STIs was poor, but prevalence, especially of HPV was high. The options for improving sexual wellbeing are limited and mostly clandestine.ConclusionRisky sexual behavior of Rwandan MSM has major implications for HIV/STI transmission. An environment of intense social stigma and social isolation makes it difficult to obtain information or services to improve sexual health. Effective interventions that address individual and contextual determinants of risk and access to health services are urgently needed to limit the consequence of MSM as a bridge for HIV transmission to the general population

Retention and mortality on antiretroviral therapy in sub-Saharan Africa: Collaborative analyses of HIV treatment programmes: Collaborative

Introduction: By 2020, 90% of all people diagnosed with HIV should receive long-term combination antiretroviral therapy (ART). In sub-Saharan Africa, this target is threatened by loss to follow-up in ART programmes. The proportion of people retained on ART long-term cannot be easily determined, because individuals classified as lost to follow-up, may have self-transferred to another HIV treatment programme, or may have died. We describe retention on ART in sub-Saharan Africa, first based on observed data as recorded in the clinic databases, and second adjusted for undocumented deaths and self-transfers. Methods: We analysed data from HIV-infected adults and children initiating ART between 2009 and 2014 at a sub-Saharan African HIV treatment programme participating in the International epidemiology Databases to Evaluate AIDS (IeDEA). We used the Kaplan-Meier method to calculate the cumulative incidence of retention on ART and the Aalen-Johansen method to calculate the cumulative incidences of death, loss to follow-up, and stopping ART. We used inverse probability weighting to adjust clinic data for undocumented mortality and self-transfer, based on estimates from a recent systematic review and meta-analysis. Results: We included 505,634 patients: 12,848 (2.5%) from Central Africa, 109,233 (21.6%) from East Africa, 347,343 (68.7%) from Southern Africa and 36,210 (7.2%) from West Africa. In crude analyses of observed clinic data, 52.1% of patients were retained on ART, 41.8% were lost to follow-up and 6.0% had died 5 years after ART initiation. After accounting for undocumented deaths and self-transfers, we estimated that 66.6% of patients were retained on ART, 18.8% had stopped ART and 14.7% had died at 5 years. Conclusions: Improving long-term retention on ART will be crucial to attaining the 90% on ART target. Naïve analyses of HIV cohort studies, which do not account for undocumented mortality and self-transfer of patients, may severely underestimate both mortality and retention on ART

J Int AIDS Soc

INTRODUCTION: By 2020, 90% of all people diagnosed with HIV should receive long-term combination antiretroviral therapy (ART). In sub-Saharan Africa, this target is threatened by loss to follow-up in ART programmes. The proportion of people retained on ART long-term cannot be easily determined, because individuals classified as lost to follow-up, may have self-transferred to another HIV treatment programme, or may have died. We describe retention on ART in sub-Saharan Africa, first based on observed data as recorded in the clinic databases, and second adjusted for undocumented deaths and self-transfers. METHODS: We analysed data from HIV-infected adults and children initiating ART between 2009 and 2014 at a sub-Saharan African HIV treatment programme participating in the International epidemiology Databases to Evaluate AIDS (IeDEA). We used the Kaplan-Meier method to calculate the cumulative incidence of retention on ART and the Aalen-Johansen method to calculate the cumulative incidences of death, loss to follow-up, and stopping ART. We used inverse probability weighting to adjust clinic data for undocumented mortality and self-transfer, based on estimates from a recent systematic review and meta-analysis. RESULTS: We included 505,634 patients: 12,848 (2.5%) from Central Africa, 109,233 (21.6%) from East Africa, 347,343 (68.7%) from Southern Africa and 36,210 (7.2%) from West Africa. In crude analyses of observed clinic data, 52.1% of patients were retained on ART, 41.8% were lost to follow-up and 6.0% had died 5 years after ART initiation. After accounting for undocumented deaths and self-transfers, we estimated that 66.6% of patients were retained on ART, 18.8% had stopped ART and 14.7% had died at 5 years. CONCLUSIONS: Improving long-term retention on ART will be crucial to attaining the 90% on ART target. Naive analyses of HIV cohort studies, which do not account for undocumented mortality and self-transfer of patients, may severely underestimate both mortality and retention on ART

J Int AIDS Soc

INTRODUCTION: "Treat All" - the treatment of all people with HIV, irrespective of disease stage or CD4 cell count - represents a paradigm shift in HIV care that has the potential to end AIDS as a public health threat. With accelerating implementation of Treat All in sub-Saharan Africa (SSA), there is a need for a focused agenda and research to identify and inform strategies for promoting timely uptake of HIV treatment, retention in care, and sustained viral suppression and addressing bottlenecks impeding implementation. METHODS: The Delphi approach was used to develop consensus around research priorities for Treat All implementation in SSA. Through an iterative process (June 2017 to March 2018), a set of research priorities was collectively formulated and refined by a technical working group and shared for review, deliberation and prioritization by more than 200 researchers, implementation experts, policy/decision-makers, and HIV community representatives in East, Central, Southern and West Africa. RESULTS AND DISCUSSION: The process resulted in a list of nine research priorities for generating evidence to guide Treat All policies, implementation strategies and monitoring efforts. These priorities highlight the need for increased focus on adolescents, men, and those with mental health and substance use disorders - groups that remain underserved in SSA and for whom more effective testing, linkage and care strategies need to be identified. The priorities also reflect consensus on the need to: (1) generate accurate national and sub-national estimates of the size of key populations and describe those who remain underserved along the HIV-care continuum; (2) characterize the timeliness of HIV care and short- and long-term HIV care continuum outcomes, as well as factors influencing timely achievement of these outcomes; (3) estimate the incidence and prevalence of HIV-drug resistance and regimen switching; and (4) identify cost-effective and affordable service delivery models and strategies to optimize uptake and minimize gaps, disparities, and losses along the HIV-care continuum, particularly among underserved populations. CONCLUSIONS: Reflecting consensus among a broad group of experts, researchers, policy- and decision-makers, PLWH, and other stakeholders, the resulting research priorities highlight important evidence gaps that are relevant for ministries of health, funders, normative bodies and research networks