Optimisation of a GMT-based cold pressing technique for low cost textile reinforced thermoplastic composites

Much potential and interest exists for the fast processing of lightweight, inexpensive composite preforms in automotive and other transport applications. As a thermoplastic matrix is more suitable for mass production with short cycle times, a novel cost-effective glass fibre reinforced thermoplastic textile preform is developed. Weft-inserted warp knitting is used to produce this textile preform containing both the reinforcing fibres and the thermoplastic matrix material as split-film ribbons. The aim of the work is to establish a useful processing technique and to control those parameters which lead to the production of good quality composite parts. The current study is specifically directed at determining the feasibility of the GMT-based cold pressing technique for the manufacturing of this new type of thermoplastic composite. An experimental design method is used to develop a statistical model which gives response surfaces of the effects of the processing parameters on the mechanical performance of the final composite part. Processing variables are ranked in order of importance to determine the optimal processing window. An economical comparison with the use of long fibre reinforced GMT mats proves the cost-efficiency of this new continuous reinforced thermoplastic composite. (C) 1999 Elsevier Science Ltd. All rights reserved.status: publishe

The effects of different standard setting methods and the composition of borderline groups: a study within a law curriculum

The aim of this study was to examine the effect of different standard setting methods on the size and composition of the borderline group, on the discrimination between different types of students and on the types of students passing with one method but failing with another. A total of 107 university students were classified into 4 different types of students and completed two examinations. Nine different methods to determine cut scores were applied. Results show that size and composition of the borderline group differed for the different standard setting methods. Results also indicate that it is difficult or even impossible to point out one method across tests as the most appropriate one in terms of discriminating between different students. Situation characteristics such as type and level of difficulty of the test are important determinants when a particular standard setting method has to be chosen.status: publishe

Lessons from PrEP: a qualitative study investigating how clinical and policy experts weigh ethics and evidence when evaluating preventive medications for use in pregnant and breastfeeding women

This study explored how multinational HIV experts weigh clinical, evidential, and ethical considerations regarding preexposure prophylaxis in pregnant/breastfeeding women. Semi-structured interviews were conducted with experts in HIV policy, research, treatment, and implementation from three global regions. A constant comparative approach identifed major themes. Experts noted that exclusion of pregnant women from research limits evidence regarding risks/benefts, emphasizing that underinclusion of pregnant women in RCTs shifts the onus of evidence-building to clinical care. Experts discussed approaches for weighing evidence to make decisions, including triangulating evidence from sources other than RCTs. Likelihood and severity of disease strongly infuenced decisions. Less efective interventions with limited fetal risk were preferred over interventions of uncertain safety, unless the disease was serious. Experts resisted the dichotomous choice between protecting maternal and fetal interests, arguing that these interests are intertwined and that more holistic approaches to maternal–fetal balance support greater inclusion of pregnant women in research

Lessons from PrEP: a qualitative study investigating how clinical and policy experts weigh ethics and evidence when evaluating preventive medications for use in pregnant and breastfeeding women

This study explored how multinational HIV experts weigh clinical, evidential, and ethical considerations regarding preexposure prophylaxis in pregnant/breastfeeding women. Semi-structured interviews were conducted with experts in HIV policy, research, treatment, and implementation from three global regions. A constant comparative approach identifed major themes. Experts noted that exclusion of pregnant women from research limits evidence regarding risks/benefts, emphasizing that underinclusion of pregnant women in RCTs shifts the onus of evidence-building to clinical care. Experts discussed approaches for weighing evidence to make decisions, including triangulating evidence from sources other than RCTs. Likelihood and severity of disease strongly infuenced decisions. Less efective interventions with limited fetal risk were preferred over interventions of uncertain safety, unless the disease was serious. Experts resisted the dichotomous choice between protecting maternal and fetal interests, arguing that these interests are intertwined and that more holistic approaches to maternal–fetal balance support greater inclusion of pregnant women in research

New thermoplastic composite preforms based on split-film warp-knitting

A newly developed type of dry thermoplastic textile preform incorporating non-crimp glass fibre reinforcements and matrix material in the form of split-film is presented. Weft-inserted warp knitting has been chosen as a textile production technique for its low cost. A specialized glass fibre/polypropylene matrix system has been proven to perform favourably in melt impregnation and to provide good composite properties. Some of the processing techniques to be applied to the new textile preform are presented, one of which is the QUIKTEMP concept for fast heating and cooling of tools for thermoplastic moulding. Composite plates produced from preliminary split-warpknit structures reveal a good potential for cost-saving while reasonable mechanical properties can be maintained. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.status: publishe

The role of male partners in women's participation in research during pregnancy: a case study from the partners demonstration project.

The exclusion of pregnant women from health research remains a significant challenge globally. In settings where cultural traditions and gender norms support a more restricted decision-making role for women in general, little is known about the attitudes of male partners toward the inclusion of women in research during pregnancy. Understanding the expectations of both men and women in such cultural settings offers an opportunity to engage and address local ethical concerns to improve women’s access to research during pregnancy and enhance intervention development. In this paper, we present a qualitative research ethics case study, drawn from the Partners Demonstration Project of pre-exposure prophylaxis (PrEP) in Kenya, regarding the role of male partners in decision-making to continue PrEP during pregnancy. PrEP is an effective HIV prevention tool; however, since pregnant women were excluded from early PrEP clinical trials, safety and efficacy data during pregnancy are limited. Given continued high rates of HIV infection for women, some pregnant women are now being provided with PrEP or are involved in PrEP research. Men and women in our study were equally concerned about the health risks of PrEP to the fetus and depended on healthcare provider guidance to understand these risks. Because the demonstration project enrolled couples, an implicit social expectation for many women’s continuation of PrEP during pregnancy was consultation with male partners. Some women reported that consenting to participate was exclusively a woman’s decision; however, many reported that they deferred to their male partner’s opinion and support during the decision-making process. Most male partners believed women should not participate in research studies without their partner’s permission, while a few men believed participation was ultimately a woman’s decision. We suggest that relational autonomy can support a middle ground for informed consent that promotes women’s autonomy while accommodating partner engagement

The role of male partners in women’s participation in research during pregnancy: a case study from the partners demonstration project

Abstract The exclusion of pregnant women from health research remains a significant challenge globally. In settings where cultural traditions and gender norms support a more restricted decision-making role for women in general, little is known about the attitudes of male partners toward the inclusion of women in research during pregnancy. Understanding the expectations of both men and women in such cultural settings offers an opportunity to engage and address local ethical concerns to improve women’s access to research during pregnancy and enhance intervention development. In this paper, we present a qualitative research ethics case study, drawn from the Partners Demonstration Project of pre-exposure prophylaxis (PrEP) in Kenya, regarding the role of male partners in decision-making to continue PrEP during pregnancy. PrEP is an effective HIV prevention tool; however, since pregnant women were excluded from early PrEP clinical trials, safety and efficacy data during pregnancy are limited. Given continued high rates of HIV infection for women, some pregnant women are now being provided with PrEP or are involved in PrEP research. Men and women in our study were equally concerned about the health risks of PrEP to the fetus and depended on healthcare provider guidance to understand these risks. Because the demonstration project enrolled couples, an implicit social expectation for many women’s continuation of PrEP during pregnancy was consultation with male partners. Some women reported that consenting to participate was exclusively a woman’s decision; however, many reported that they deferred to their male partner’s opinion and support during the decision-making process. Most male partners believed women should not participate in research studies without their partner’s permission, while a few men believed participation was ultimately a woman’s decision. We suggest that relational autonomy can support a middle ground for informed consent that promotes women’s autonomy while accommodating partner engagement

HIV-uninfected Kenyan adolescent and young women share perspectives on using pre-exposure prophylaxis during pregnancy

To optimize scale-up of pre-exposure prophylaxis (PrEP) for pregnant women at risk of HIV in high HIV burden settings, implementation strategies must be developed that account for perceptions of PrEP in this unique population. Semistructured focus group discussions were conducted with 68 HIV-uninfected Kenyan pregnant and postpartum women without prior PrEP knowledge or experience. A qualitative descriptive analysis was performed, using a constant comparison approach, to identify key themes related to the values and rationale impacting potential PrEP use in pregnancy. Median age was 19.5 years and participants were either pregnant or had 1–2 children. Almost all (96%) were married or had a steady partner. Women felt pregnancy was a time of high HIV risk because they desired sex less frequently, which may lead their partners to have outside partnerships. This made PrEP an attractive HIV prevention option for themselves and their infants. Although women believed male partner behaviors influenced their HIV risk, many women perceived that male partners would react negatively, including becoming physically violent, if they discovered that women used PrEP. Clinicians were identified as potential facilitators of PrEP use who could explain PrEP to male partners on behalf of pregnant women. Women said that community-level stigma against HIV and potential for conflating PrEP with antiretroviral therapy (ART) would necessitate that PrEP use be discreet. Our results indicate the importance of addressing risk perception of women, concerns of male partners, HIV stigma, and benefits of PrEP for HIV prevention as programs are developed for pregnant women