Global awareness of material sustainability has increased the demand for bio-based polymers like poly(lactic acid) (PLA), which are seen as a desirable alternative to fossil-based polymers because they have less environmental impact. PLA is an aliphatic polyester, primarily produced by industrial polycondensation of lactic acid and/or ring-opening polymerization of lactide. Melt processing is the main technique used for mass production of PLA products for the medical, textile, plasticulture, and packaging industries. To fulfill additional desirable product properties and extend product use, PLA has been blended with other resins or compounded with different fillers such as fibers, and micro- and nanoparticles. This paper presents a review of the current status of PLA mass production, processing techniques and current applications, and also covers the methods to tailor PLA properties, the main PLA degradation reactions, PLA products' end-of-life scenarios and the environmental footprint of this unique polymer.

The concept of social capital has drawn much attention in social and behavioral epidemiology and health education research. The purpose of this study is to develop the 'Personal Social Capital Scale' for quantitative survey studies of social factors that are related to health and behavior. The instrument contained 10 composite items based on 42 items for assessing personally owned social capital, including bonding and bridging capitals. The instrument was assessed using cross-sectional survey data collected among 128 participants (64 women) with a participation rate of 95%. Results from correlation and confirmatory factor analysis indicated adequate reliability and internal consistency. The mean score of the scale was 25.9 (SD = 5.2) for total social capital, 15.2 (SD = 3.0) for bonding social capital and 10.8 (SD = 3.4) for bridging social capital. The scale scores significantly predicted a number of theoretically related factors, including people skills, being sociable, social capital investment, informational support, instrumental support, emotional support and collective efficacy. This instrument provides a new tool for cross-cultural research to assess personally owned social capital.

Data from 2,153 sexually active rural-to-urban migrants in China were analyzed to examine the relationship between the movement of rural-to-urban migration and increased HIV/STD (sexually transmitted disease) risk and the applicability of constructs of a Western-based theory of behavioral change to the study population. Measurements included migrant mobility, sexual risk, and the seven constructs of the protection motivation theory (PMT). Data in the current study suggest that high mobility among rural-to-urban migrants was associated with increased sexual risk. The PMT constructs are applicable in identifying perceptions and attitudes associated with sexual risk behaviors in this culturally distinct population. Increased sexual risk was associated with increased perceptions of extrinsic rewards, intrinsic rewards, and response cost. Also consistent with PMT, increased sexual risk was associated with perceptions of decreased severity, vulnerability, response efficacy, and self-efficacy. After controlling for a number of key confounding factors, all seven PMT constructs were associated with sexual risk in the manner posited by the theory. The association between mobility and sexual risk underscores the importance of effective HIV/STD prevention efforts among this vulnerable population. The social cognitive theories including the PMT may form a logical base for prevention intervention programs targeting rural-to-urban migrants in China.

Factors such as high rates of FSW patronage, low rates of condom use during commercial sex, having sex with both commercial and noncommercial sexual partners, and high rates of STD infection may promote a heterosexual epidemic in China.

There are over 100 million individuals in China who have migrated from rural villages to urban areas for jobs or better lives without permanent urban residency (i.e., "rural-to-urban migrants"). Our preliminary data from ongoing research among rural-to-urban migrants in China suggest that the migrant population is strongly stigmatized. Moreover, it appears that substantial numbers of these migrants experience mental health symptoms (e.g., depression, anxiety, hostility, social isolation). While the population potentially affected is substantial (more than 9% of the entire population or about one-quarter of the rural labour force in mainland China) and our data seem to indicate that the issue is pervasive in this population, there is limited literature on the topic in China or elsewhere. Therefore, in the current article, we utilize secondary data from public resources (i.e., scientific literature, governmental publications, public media) and our own qualitative data to explore the issues of stigmatization and mental health, to propose a conceptual model for studying the association between the stigmatization and mental health among this population, and to identify some future needs of research in this area.

Previous studies suggested a rapid increase of HIV prevalence among MSM in China in recent years, from 0.4% in 2004 to 5.8% in 2008. However, some MSM had never been tested for HIV. In order to expand the accessibility to HIV testing, understanding HIV testing behavior and barriers among MSM is important. Using data collected from 307 young migrant MSM (aged 18-29 years) in 2009 in Beijing, we aimed to identify psychological and structural barriers to HIV testing. MSM were recruited through peer outreach, informal social networks, internet outreach, and venue-based outreach. Participants completed a confidential self-administered questionnaire.Results show that about 72% of MSM had ever had HIV testing. Logistic regression analysis indicated that the HIV testing behavior was associated with sexual risk behaviors (e.g., multiple sexual partners, inconsistent condom use for anal sex) and history of STDs. Eighty four MSM (28%) who had never had HIV testing reported that the psychological barriers mainly were perceived low risk of HIV infection and fears of being stigmatized. The structural barriers reported included inconvenience of doing test and lack of confidentiality. Future HIV prevention programs should be strengthened among MSM to increase their awareness of HIV risk. Efforts are needed to increase access to quality and confidential HIV testing among MSM and reduce stigma against MSM.

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Status-based discrimination and inequity have been associated with the process of migration, especially with economics-driven internal migration. However, their association with mental health among economy-driven internal migrants in developing countries is rarely assessed. This study examines discriminatory experiences and perceived social inequity in relation to mental health status among rural-to-urban migrants in China. Cross-sectional data were collected from 1,006 rural-to-urban migrants in 2004–2005 in Beijing, China. Participants reported their perceptions and experiences of being discriminated in daily life in urban destination and perceived social inequity. Mental health was measured using the symptom checklist-90 (SCL-90). Multivariate analyses using general linear model were performed to test the effect of discriminatory experience and perceived social inequity on mental health. Experience of discrimination was positively associated with male gender, being married at least once, poorer health status, shorter duration of migration, and middle range of personal income. Likewise, perceived social inequity was associated with poorer health status, higher education attainment, and lower personal income. Multivariate analyses indicate that both experience of discrimination and perceived social inequity were strongly associated with mental health problems of rural-to-urban migrants. Experience of discrimination in daily life and perceived social inequity have a significant influence on mental health among rural-to-urban migrants. The findings underscore the needs to reduce public or societal discrimination against rural-to-urban migrants, to eliminate structural barriers (i.e., dual household registrations) for migrants to fully benefit from the urban economic development, and to create a positive atmosphere to improve migrant's psychological well-being.