BPA in composites and plastic bottles Article Example | Topics and Well Written Essays - 1000 words

BPA in composites and plastic bottles - Article Example To systematically compile and critically evaluate the literature charac-terizing BPA content of dental materials; to assess BPA exposures from dental materials and potential health risks; and to develop evidence-based guidance for reducing BPA exposures while promoting oral health. The extant toxicological literature and material safety data sheets were used as data sources. BPA is released from dental resins through salivary enzymatic hydrolysis of BPA derivatives, and BPA is detectable in saliva for up to 3 hours after resin placement. The quantity and duration of systemic BPA absorption is not clear from the available data. Dental products containing bisphenol A derivative glycidyl dimethacrylate (bis-GMA) are less likely to be hydrolyzed to BPA and have less estrogenicity than those containing bisphenol A dimethacrylate (bis-DMA). Most other BPA derivatives used in dental materials have not been evaluated for estrogenicity. BPA exposure can be reduced by cleaning and rinsing surf aces of sealants and composites immediately after placement. On the basis of the proven benefits of resin-based dental materials and the brevity of BPA exposure, we recommend continued use with strict adherence to precautionary application techniques. Use of these materials should be minimized during pregnancy whenever possible. Manufacturers should be required to report complete information on the chemical composition of dental products and encouraged to develop materials with less estrogenic potential. Title: Doctors Warn Women Against Hot Drinks with Plastic Covers Proponents: China Post Writers Source: China Post 13 Feb. 2011. Health Reference Center Academic. Web. 24th March 2011. Abstract: The China Post news staff -- Doctors have warned people, women in particular, against sipping hot beverages through the small holes in plastic cup covers which, when heated, may release the harmful compound bisphenol A (BPA), a report said yesterday. Chien Chi-cheng from Taiwan's association of gynecologists and obstetricians, said BPA can be found in many plastic products and long-term intake of the toxic chemical may seriously harm one's health, the United Evening News reported. BPA can accumulate in the body and cause harm to women's hormone systems, menstruation, and pregnancy, he said. Like other environmental hormones, BPA can pass onto pregnant women's babies. Chien noted that examinations of babies' umbilical cord blood over the past few years have returned unexpected results. Their blood contains a few hundred chemicals, including many environmental hormones such as BPA. The association pointed out that of the recyclable plastic products, categories No. 3 and No. 6 will release BPA under high temperatures X 70 degrees Celsius and above. It noted that many major chain stores use No. 6 plastic covers for their hot coffee. Chien was cited by the paper as saying he is worried every time he sees a woman sipping hot coffee directly through the small hole in such pla stic covers. Although one cup of coffee may only produce a very small amount of environmental hormones, long-term exposure will accumulate to a frightening level, Chien reportedly said. Meanwhile, another doctor noted that environmental hormones found in automobile exhaust may cause male infertility. Chen Si-yuan, a professor from the gynecology

Assumptions and Design Essay Example | Topics and Well Written Essays - 500 words

Assumptions and Design - Essay Example The researcher’s basic beliefs or assumptions guide him/her about research methods, including the researcher’s ontological beliefs (beliefs about the nature of reality), epistemological beliefs (beliefs about what is possible to know), and axiological beliefs (beliefs about what is ethical and the role of values in research). Armour Peterson article employs qualitative design to study post homicide experience of family members of homicide victims (Armour, 2002). Qualitative research design, such as the one employed by Armour, is designed to riposte to questions regarding the intricate nature of occurrences with the aim of explaining, describing, and understanding the phenomena being researched (Creswell, 2003). The author beliefs that the relatives of homicide victims are an ignored lot and their post homicide experiences are molded by the social ambiance and the superiority of the government’s schema for justice. The choice of qualitative method is further supported by the author’s belief that attention to the needs of this population is limited, and hence the need for a qualitative method to generate knowledge and explain various aspects. Since only very few empirical researches exist about post homicide experiences of the family members of the homicide victims, the researcher had to record words and phrases and then look for meaning, concepts or theories. In addition, the post homicide experiences of each family vary greatl y; the researcher had to adopt a qualitative design since full and rich data is scarce and is not obtainable through quantitative studies. Data is best obtained through taking comprehensive notes, recording conversations and writing detailed observations. Mixed methods would combine both quantitative and qualitative approaches. In applying mixed methods, the philosophical assumption would be that findings about post homicide experiences could be generalized across all the families of the homicide victims. To