779 research outputs found
Determination and distribution of polycyclic aromatic hydrocarbons in rivers, surface runoff, and sediments in and around Thohoyandou, Limpopo Province, South Africa
Water quality in rural areas is affected adversely by build-up of traffic-generated organic compounds on road surfaces, leading to their presence in water runoff and sediments. Characterising these compounds is a first step in developing measures for the removal of such pollutants from water courses. In this study, liquid-liquid extraction of water samples from several rivers and surface run-off enabled quantification of major PAHs. Soxhlet extraction of sediment samples was followed by clean-up of samples using column chromatography. The PAHs were quantified by gas chromatography. In water and sediment samples, 6 PAHs were identified and quantified. In river water samples, individual PAH levels ranged between 0.1 µg/. and 137 µg/., while in sediment samples levels ranged between 17.9 µg/kg and 9870 µg/kg. For surface run-off, levels ranged between 0.6 µg/. and 2 500 µg/. for water samples and between 112 µg/kg and 34 400 µg/kg for sediment samples. Total levels of PAHs in sediment samples were relatively high (111.6 to 61 764 µg/kg) compared to those in water from both river and surface run-off (29.2 to 3 064.8 µg/.), and PAH levels in surface runoff were much higher than in river waters, implicating tarred roads and parking lots as main point sources of PAHs. PAH ratios also indicate that the PAH content of runoff and sediment is more likely due to pyrogenic sources, i.e. vehicle emissions, although petrogenic sources (mainly oil spills) also play an important role. Toxic Equivalence Quotient (TEQ) values in river and runoff waters ranged from 0.10 to 4.03 µg/. and for sediments the TEQ ranged from 0.50 to 272.23 µg/kg. These results are of concern, as the calculated TEQ is likely to be an underestimate of the actual TEQ, since only 6 PAHs with relatively low toxicities were analysed. Long droughts and low rainfall, and washing of automobiles in and near the rivers are important factors which may have contributed to the observed levels of PAHs in both river water and sediments.Keywords: Polycyclic aromatic hydrocarbon, river water, runoff, sedimen
A New Flavonol from Athrixia phylicoides (Bush Tea)
Athrixia phylicoides (bush tea), belonging to the Asteraceae family, is a popular beverage used as a herbal tea and for medicinal purposes. The processed leaves of bush tea contain 5-hydroxy-6,7,8,3’,4’,5’-hexamethoxyflavon-3-ol as major flavonoid.KEYWORDS: Athrixia philicoides, bush tea, flavonoids, health beverage, phenols
Play is indispensable for an adequate development of coping with social challenges in the rat
In this study, young rats were deprived of early social interactions during weeks 4 and 5 of life. Different behavior al tests were conducted in adulthood to study the behavioral responses of rats lacking ear ly social experiences. Juvenile deprivation resulted in decreased social activity and an altered sexual pattern, but did not affect locomotor activity or the performance in the elevated plus maze. Furthermore, behavioral and neuroendocrine responses of juvenile isolated rats were dramatically altered when they were confronted with territorial aggression. Juvenile deprived rats did not readily display a submissive posture in response to the resident and showed no immobility behavior after being returned to the resident's territory, while their plasma corticosterone and adrenaline concentrations;were significantly increased compared to nonisolated controls. In contrast, behavioral responses in the shock prod test were not affected by previous isolation. The results suggest that early social experiences are vital for interactions with conspecifics later in life, i.e., aggression, sexual, and social interactions; (C) 1999 John Wiley & Sons, Inc
Burden of illness of hip fractures in elderly Dutch patients
Summary: Patients with hip fractures experience reduced health-related quality of life and have a reduced life expectancy. Patients’ utilization of healthcare leads to costs to society. The results of the study can be used in future economic evaluations of treatments for hip fractures. Purpose: Hip fractures are associated with high mortality, reduced quality of life, and increased healthcare utilization, leading to an economic burden to society. The purpose of this study is to determine the burden of illness of hip fractures in elderly Dutch patients for specific time periods after surgery. Methods: Patients with a hip fracture above the age of 65 were included in the study. In the 1-year period after surgery, patients were asked to complete a set of questionnaires pre-injury (retrospectively), and 1 week, 1 month, 3 months, 6 months and 12 months after surgery. The set of questionnaires included the Euroqol 5D (EQ-5D-3L), the iMTA Medical Consumption Questionnaire (iMCQ) and iMTA Productivity Cost Questionnaire (iPCQ). Health-related quality of life was calculated using Dutch tariffs. Costs were calculated using the methodology described in the Dutch costing manual. Results: Approximately 20% of patients with a hip fracture died within 1 year. Health-related quality of life was significantly reduced compared to pre-injury values, and patients did not recover to their pre-injury values within 1 year. Total costs in the first year after injury were €27,573, of which 10% were due to costs of the procedure (€2706). Total follow-up costs (€24,876) were predominantly consisting of healthcare costs. Monthly costs decreased over time. Conclusions: Hip fractures lead to a burden to patients, resulting from mortality and health-related quality of life reductions, and to society, due to (healthcare) costs. The results of this study can be used in future economic evaluations
Status of road ecology research in Africa : do we understand the impacts of roads, and how to successfully mitigate them?
Across Africa, transport infrastructure, including roads, is being built in over 30 planned
development corridors that are likely to have major impacts on remaining natural habitats
and associated biodiversity. Linked to this is the projected increase in human population
size, which is predicted to grow by 1.3 billion people by 2050. Road ecology is the study
of the ecological effects (both positive and negative) of roads and traffic but is perceived
to be under-researched in Africa. In this context, we undertook a systematic review of
road ecology research in Africa to understand the geographic and taxonomic scope
of work undertaken to date, as well as recommendations for reducing the impacts of
roads. We discovered 210 road ecology publications from Africa (published between
1954 and 2016), with most publications from the more affluent and politically stable
regions (e.g., southern and East Africa). We found more publications than expected,
with relevant research concealed within studies whose primary focus was on other
topics. Most publications (1) focused on single species, and in particular on mammals
(where chimpanzees and forest elephants were most studied); (2) were from southern
Africa; and 3) were conducted in the grassland and savannah biome and the tropical
and subtropical forest biome. Most publications examined the direct impacts of roads,
in particular wildlife-vehicle collisions. Only one-third of the publications provided some
form of recommendation for intervention to reduce or mitigate the impacts of roads,
based on evidence from the publication. Most recommended interventions related to
ecosystem or natural process recreation, as well as site and area stewardship. Gaps
and future directions for research include rigorous testing of measures to mitigate the
impacts of roads, inclusion of traffic monitoring in studies, understanding the impacts of
upgrading roads, and exploring livelihood, economic and moral incentives and education
and training as potential interventions for reducing the impacts of roads. Our review
has highlighted the need for accelerating the study of the impacts of roads on natural
habitats and biodiversity, in light of planned large-scale infrastructure development, and especially the study of appropriate mitigation measures that can be rigorously assessed
and implemented before and during construction and upgrading of roads in Africa.http://www.frontiersin.org/Ecology_and_Evolutionam2020Mammal Research Institut
Phase Separation in Ge-Rich GeSbTe at Different Length Scales: Melt-Quenched Bulk versus Annealed Thin Films
Integration of the prototypical GeSbTe (GST) ternary alloys, especially on the GeTe-Sb2Te3 tie-line, into non-volatile memory and nanophotonic devices is a relatively mature field of study. Nevertheless, the search for the next best active material with outstanding properties is still ongoing. This search is relatively crucial for embedded memory applications where the crystallization temperature of the active material has to be higher to surpass the soldering threshold. Increasing the Ge content in the GST alloys seems promising due to the associated higher crystallization temperatures. However, homogeneous Ge-rich GST in the as-deposited condition is thermodynamically unstable, and phase separation upon annealing is unavoidable. This phase separation reduces endurance and is detrimental in fully integrating the alloys into active memory devices. This work investigated the phase separation of Ge-rich GST alloys, specifically Ge5Sb2Te3 or GST523, into multiple (meta)stable phases at different length scales in melt-quenched bulk and annealed thin film. Electron microscopy-based techniques were used in our work for chemical mapping and elemental composition analysis to show the formation of multiple phases. Our results show the formation of alloys such as GST213 and GST324 in all length scales. Furthermore, the alloy compositions and the observed phase separation pathways agree to a large extent with theoretical results from density functional theory calculations
School performance and behavioral functioning in children after intrauterine transfusions for hemolytic disease of the fetus and newborn
Developmen
Endodontic management of traumatized permanent teeth : a comprehensive review
The pulp plays a key role in the treatment of traumatic dental injuries (TDIs) and is strongly associated with the outcome, particularly in severe cases. A correct pulp diagnosis is essential as it forms the basis for developing the appropriate management strategy. However, many TDIs are complex, and their treatment requires a profound knowledge of the physiological and pathological responses of the affected tissues. This comprehensive review will look at the dentine-pulp complex and its interaction with the surrounding tissues following TDIs. The literature up to 2020 was reviewed based on several searches on PubMed and the Cochrane Library using relevant terms. In addition to the recently revised guidelines of the International Association of Dental Traumatology, this article aims to provide background information with a focus on endodontic aspects and to gather evidence on which a clinician can make decisions on the choice of the appropriate endodontic approach for traumatized permanent teeth.Peer reviewe
European Society of Endodontology position statement : endodontic management of traumatized permanent teeth
This position statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the endodontic management of traumatized permanent teeth. A recent comprehensive review with detailed background information provides the basis for this position statement (Krastl et al. 2021, International Endodontic Journal, ). The statement is based on current scienti?c evidence as well as the expertise of the committee. Complementing the recently revised guidelines of the International Association of Dental Traumatology, this position statement aims to provide clinical guidance for the choice of the appropriate endodontic approach for traumatized permanent teeth. Given the dynamic nature of research in this area, this position statement will be updated at appropriate intervals.Peer reviewe
European Society of Endodontology position statement : endodontic management of traumatized permanent teeth
This position statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the endodontic management of traumatized permanent teeth. A recent comprehensive review with detailed background information provides the basis for this position statement (Krastl et al. 2021, International Endodontic Journal, ). The statement is based on current scienti?c evidence as well as the expertise of the committee. Complementing the recently revised guidelines of the International Association of Dental Traumatology, this position statement aims to provide clinical guidance for the choice of the appropriate endodontic approach for traumatized permanent teeth. Given the dynamic nature of research in this area, this position statement will be updated at appropriate intervals.Peer reviewe
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