141 research outputs found
A comparison of the results from intra-pleural and intra-peritoneal studies with those from inhalation and intratracheal tests for the assessment of pulmonary responses to inhalable dusts and fibres.
The aim of this paper is to compare results from inhalation studies with those from intraperitoneal and intrapleural tests, where available, for a number of fibrous and particulate test materials. The objective is to determine how well intraperitoneal/intrapleural studies predict the pathological responses observed in more standard in vivo studies of pulmonary toxicity, with a particular focus on carcinogenicity. Published toxicity data was obtained for a number of materials including asbestos, wollastonite, MMVFs (including glass fibres, stone wools and RCF), silicon carbide whiskers, potassium octatitanate, quartz, kevlar, polypropylene and titanium dioxide. For some of the fibrous material reviewed, there is conformity between the results of intraperitoneal and inhalation tests such that they are either consistently positive or consistently negative. For the remaining fibrous materials reviewed, intraperitoneal and inhalation tests give different results, with positive results in the intraperitoneal test not being reflected by positive inhalation results. It is suggested that the intraperitoneal test can be used to exonerate a dust or fibre (because if negative in the intraperitoneal test it is extremely unlikely to be positive in either inhalation or intratracheal tests) but should not be used to positively determine that a dust or fibre is carcinogenic by inhalation. We would argue against the use of intraperitoneal tests for human health risk assessment except perhaps for the purpose of exoneration of a material from classification as a carcinogen.Peer reviewedFinal Accepted Versio
The New Globalism:Reflections on the EU and the USA in Asia
The basic thesis of this paper is that Southeast Asia will be the crucible and the testing ground for a new Euro-American partnership. Both the United States and the European Union have vital interests in Southeast Asia. These interests certainly involve economics. They definitely concern security issues. And, for both the United States and the European Union, though for similar reasons differently nuanced, these interests aspire to the realm of ideals and idealism, of norms and normativism
Synthesis and antibacterial activities of enamine derivatives of dehydroacetic acid
Dehydroacetic acid is a common pyrone derivative used commercially as an antibacterial and antifungal agent. Based on the synthesis of dehydroacetic acid (1) from N-hydroxysuccinimdyl acetoacetate, a novel series of enamine-based derivatives were synthesised in order to improve the antibacterial activity of dehydroacetic acid. The antibacterial activities of the synthesised analogues were evaluated against Escherichia coli and Staphylococcus aureus. Derivative 4d (N-Ph) was identified as the most potent inhibitor of S. aureus growth. Overall, derivative 4b (N-Me) showed the best broad-spectrum activity with five-fold greater minimum inhibitory concentration and 11-fold greater minimum biocidal concentration against E. coli when compared to dehydroacetic acid, in addition to improved antibacterial activity against S. aureus
Biomonitoring for workplace exposure to copper and its compounds is currently not interpretable
This paper sets out to explore the requirements needed to recommend a useable and reliable biomonitoring system for occupational exposure to copper and its inorganic compounds. Whilst workplace environmental monitoring of copper is used to measure ambient air concentrations for comparison against occupational exposure limits, biological monitoring could provide complementary information about the internal dose of workers, taking into account intra-individual variability and exposure from all routes. For biomonitoring to be of reliable use for copper, a biomarker and the analytical ability to measure it with sufficient sensitivity must be identified and this is discussed in a range of matrices. In addition, there needs to be a clear understanding of the dose-response relationship of the biomarker with any health-effect (clinical or sub-clinical) or, between the level of external exposure (by any route) and the level of the copper biomarker in the biological matrix being sampled, together with a knowledge of the half-life in the body to determine accurate sampling times. For many biologically non-essential metals the requirements for reliable biomarkers can be met, however, for ‘essential’ metals such as copper that are under homeostatic control, the relationship between exposure (short- or long-term) and the level of any copper biomarker in the blood or urine is complex, which may limit the use and interpretation of measured levels. There are a number of types of biomarker guidance values currently in use which are discussed in this paper, but no values have yet been determined for copper (or its inorganic compounds) due to the complexity of its essential nature; the US The American Conference of Governmental Industrial Hygienists (ACGIH) has however indicated that it is considering the development of a biological exposure index for copper and its compounds. In light of this, we present a review of the reliability of current copper biomarkers and their potential use in the occupational context to evaluate whether there is value in carrying out human biomonitoring for copper exposure. Based on the available evidence we have concluded that the reliable use of biomonitoring of occupational exposure to copper and its application in risk assessment is not possible at the present time
THE EFFICACY OF FEEDBACK IN THE FIRST YEAR PROGRAMME: A COMPARISON OF THE VIEWS OF STUDENTS AND STAFF
Feedback has been defined as "information about the gap between actual performance level and the reference level, which is subsequently used to alter that gap". It is now widely acknowledged that feedback forms an essential part of the learning cycle, allowing students to assess their performance and make improvements to future work. However, despite acceptance of the importance of feedback by academics, results from the recent National Student Survey (2005) have highlighted students' general dissatisfaction with the feedback they receive. The purpose of this study was to examine the efficacy of feedback on the first year of the Biological Sciences degree at the University of Leicester, by comparison of the perceptions of students and staff on a number of aspects of the current feedback process. Although a structured approach to giving feedback is encouraged within the School of Biological Sciences, there will be remaining differences in the way staff and students conceptualise the roles of feedback and its format. The views of students studying on the 1st and 2nd years of the Biological Sciences degree were ascertained using a questionnaire addressing various aspects of feedback including, quantity, timing, use and quality. The response rates to the questionnaire were high for both years and the views of students with a range of academic abilities were represented; statistical analysis showed the data obtained to be reliable. In addition, focus groups were used to further explore the views of 1st year students. Semi-structured discussions were led by non-teaching staff, allowing for an informal environment to encourage full participation from students with a range of academic abilities. Staff views on the feedback process were sought during semi-structured one-on-one interviews, again allowing an informal environment for discussion. The staff cohort comprised the majority of 1st year module course convenors, a group of 1st year personal tutors, representative of most departments within the School of Biological Sciences and staff from the Student Learning Centre
Setting evidence-based occupational exposure limits for manganese
In 2004, a review by the Institute of Environment and Health (IEH) made recommendations on occupational exposure limits (OELs) for manganese and its inorganic compounds for inhalable and respirable fractions respectively. These OELs were based on a detailed comprehensive evaluation of all the scientific data available at that time. Since then, more published studies have become available and a number of occupational standard-setting committees (EU SCOEL, US ACGIH-TLV, and German MAK) have proposed OEL’s for manganese and its inorganic compounds that are somewhat lower that those proposed in the 2004 review.
Based on current understanding, the key toxicological and human health issues that are likely to influence a health-based recommendation relate to: neurotoxicology; reproductive and developmental toxicology; and mutagenicity/carcinogenicity. Of these, it is generally considered that neurotoxicity presents the most sensitive endpoint. As such, many of the studies that have been reported since the IEH review have sought to use those neurofunctional tests that appear to be particularly sensitive at identifying the subtle neurological changes thought to associate with manganese toxicity. These recent studies have, however, continued to be limited to a significant extent by reliance on cross-sectional designs and also by use of unreliable exposure estimation methods. Consequently the strength of the potential association between manganese exposure and these subtle subclinical cognitive or neuromotor changes is still poorly characterised and the relevance of these minor differences in terms of either their clinical or quality of life consequences remains unknown.
Based upon the overall evidence, it is concluded that the 8-h time weighted averages (TWA) for respirable (0.05 mg/m3 as Mn) and inhalable (0.2 mg/m3 as Mn) fractions as recommended by the SCOEL in 2011 are the most methodologically-sound, as they are based on the best available studies, most suited to the development of health-based OELs for both respirable and inhalable fractions. The dose-response characterisation informed by the examined studies used can be considered to establish a true human NOAEL for all the neurofunctional endpoints examined within the selected studies
Disclosures about important life events on Facebook: Relationship with stress and quality of life
a b s t r a c t The current study examined the relationship between general perceived levels of stress, quality of life, social networking usage, and disclosing important life events on Facebook in order to better understand the complex relationship between online disclosure and individual well-being. An online survey was completed by adult Facebook users aged 18-70. Results indicate that the more time spent on and the more social network memberships, the higher stress and lower quality of life; Facebook-specific usage was unrelated to either well-being variable. Together, these findings suggest that the current increase in social media variety and usage may be detrimental to user well-being. Users who shared important, bad health news on Facebook had higher stress and lower quality of life than those who did not, with no significant differences for sharing good health news. The more that users did not share important news on Facebook for self-protection and friend unresponsiveness reasons, the greater their stress. The self-protection reason was also negatively related to quality of life. These inconsistent findings can likely be partially explained by the nature of the information that is shared. These findings are discussed in light of disclosure and relationship patterns on social networks
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