bluuebunny/crossref_metadata_2025_split huggingface dataset:
Problems of Nepalese hydropower projects due to suspended sediments
Authors: Thapa Bhola , Shrestha Raju , Dhakal Projjwal , Thapa Biraj Singh 
Published: June 2007

Nepal has high potential for hydropower due to glaciers in the Himalayas, regular monsoon rain and local topography. Himalayan Rivers contain large quantities of sediment with hard abrasive particles, which is a hurdle for the economic exploitation of hydropower resources. Erosion of the earth's surface takes place because of influence of climatic, tectonic and human activities. Almost all the power plants in the Himalayan region are affected by excessive sediment in rivers that reduce the life of plants either by filling reservoirs or by erosion of turbine components. The design and operation of headwork components in hydropower plants can only manipulate sediment particle size and hence only sediment concentration in the water. The erosion of hydraulic machinery depends on eroding particles, that is, their size, shape and hardness; on substrates, their chemistry, elastic properties, surface hardness and surface morphology; and on operating conditions, velocity, impingement angle and concentration. The shape, size and mineral content of sediment vary at different locations of the same river system depending on distance traversed by particles, gradient of the river and the geological formation of the river course and catchment areas.
The Khimti hydropower project in Nepal represents a typical high head power plant in the Himalayan River that is affected by river sediment. Erosion tests of turbine material carried out at Kathmandu University revealed the dependence of erosion rate on mineral content. The erosion tests have shown trends relative to the quartz content present in samples from river basins in different parts of the country. There was some indication that the shape of particles had some effect. Sediments in the hydropower projects are normally considered as a burden, but there is scope for industrial use of these sediments.
Students' Experiences of Ability Grouping—disaffection, polarisation and the construction of failure1
Authors: Boaler Jo , Wiliam Dylan , Brown Margaret 
Published: June 2007

ABSTRACTThis paper reports findings from the first two years of a four‐year longitudinal study into the ways that students' attitudes towards, and achievement in, mathematics are influenced by ability‐grouping practices in six schools. Through the use of questionnaires administered to the whole cohort of 943 students, interviews with 72 students and approximately 120 hours of classroom observation, the relative achievement in, and the changes in attitudes towards, mathematics are traced as the students move from year 8 to year 9, with students in four of the six schools moving from mixed‐ability grouping to homogenous ability groups or ‘sets’. Ability‐grouping was associated with curriculum polarisation. This was enacted through restriction of opportunity to learn for students in lower sets, and students in top sets being required to learn at a pace which was, for many students, incompatible with understanding. The same teachers employed a more restricted range of teaching approaches with ‘homogeneous’ groups than with mixed‐ability groups which impacted upon the students' experiences in profound and largely negative ways. Almost all of the students interviewed from ‘setted groups’ were unhappy with their placement.
Infringement versus conviction: the social impact of a minor cannabis offence in South Australia and Western Australia
Authors: Lenton Simon , Humeniuk Rachel , Heale Penny , Christie Paul 
Published: June 2007

AbstractQuantitative data is reported from a study of 68 South Australians who had received an infringement notice or ‘cannabis expiation notice’ (CEN) and 68 West Australians who received a criminal conviction for a minor cannabis offence not more than 10 years ago to compare impact of the infringement notice and the conviction on their lives. The majority of both groups saw themselves as largely law‐abiding, had respect for the law in general and had positive views regarding cannabis. However, more of the convicted group, compared to the infringement notice group, reported negative employment consequences (32% vs. 2%), further problems with the law (32% vs. 0%), negative relationship consequences (20% vs. 5%)and accommodation consequences (16%vs. 0%)as a result of their apprehension. While neither conviction nor infringement deterred subsequent cannabis use for the vast majority, the negative social impacts of conviction were far greater than those resulting from an infringement notice. The findings have implications for the legislative options for regulation of cannabis possesssion and use.
Independent Regulation of ABCB1 and ABCC Activities in Thymocytes and Bone Marrow Mononuclear Cells during Aging
Authors: Kyle‐Cezar F. , Echevarria‐Lima J. , Rumjanek V. M. 
Published: June 2007

AbstractAging modifies a number of functional and phenotypic parameters of cells from the immune system. In this study, the activities of two members of the superfamily of ATP‐binding cassette (ABC) transport proteins, ABCB1 and ABCC (measured by rhodamine 123 efflux and Fluo‐3 efflux respectively), were compared in murine bone marrow cells and thymocytes of young (3–4 weeks old), adult (2–3 months old) and old (18 months old) mice. ABCB1 activity was shown to be age regulated in murine bone marrow mononuclear cells and thymocytes. In the bone marrow, the increased amount of cells with ABCB1 activity observed in old mice was restricted to the c‐kit−Sca‐1+ and c‐kit+Sca‐1+ subpopulations. Only a small percentage of c‐kit+ cells in the thymus had ABCB1 activity, and this subpopulation increased with age. In the thymus, old age augmented this activity in the CD4− CD8− double‐negative cells and in the CD4+ and CD8+ single‐positive populations. The activity of another ABC transporter, the ABCC‐related activity, was also modified by age in the bone marrow. However, the age‐related increase was observed in the subpopulations were ABCB1 was not modified, namely the non‐progenitor population (c‐kit−Sca‐1−cells) and c‐kit+Sca‐1− cells. Nearly, all thymocytes expressed the ABCC1 molecule in an active form and aging did not affect this pattern. This study demonstrates an independent upregulation of ABCB1 and ABCC activities during the aging process. The increases were observed in different subsets of cells but followed a developmentally regulated pattern. The functions played by these transporters and alterations in aging are discussed.
Universal Optimization of Flight Initiation Distance and Habitat‐Driven Variation in Escape Tactics in a Namibian Lizard Assemblage
Authors: Cooper William E. , Whiting Martin J. 
Published: June 2007

AbstractSome aspects of escape predicted by theoretical models are intended to apply universally. For example, flight initiation distance (distance between an approaching predator and prey when escape begins) is predicted from predation risk and the costs of escaping. Escape tactics and refuge selection are not currently predicted by theoretical models, but are expected to vary with structural features of the habitat. One way of studying such variation is to compare aspects of antipredatory behavior among sympatric species that differ in habitat or microhabitat use. In an assemblage of lizards in northwestern Namibia, we conducted experiments to test predictions of escape theory for three risk factors in representatives of three families and observed escape tactics in additional species. As predicted by escape theory, flight initiation distance increased with directness of a predator's approach and predator speed in Agama planiceps, Mabuya acutilabris, and Rhotropus boultoni, and with distance from refuge in M. acutilabris. As predicted by theory, the probability of entering refuge increased with risk in R. boultoni. All available data indicate that flight initiation distance and refuge entry by lizards conform to theoretical predictions. Escape tactics varied greatly as a function of habitat type: (1) arboreal species fled up and around trees and sometimes entered tree holes; (2) saxicolous species used rock crevices as refuges, but differed in tactics prior to entering refuges; and (3) terrestrial species fled into bushes or other vegetation, often to the far sides of them. Some M. acutilabris entered small animal burrows or buried themselves in sand beneath bushes. Escape tactics varied even among congeners in Mabuya, highlighting the important effect of habitat structure on them. Although habitat partitioning has traditionally been viewed as favoring species coexistence, an interesting by‐product appears to be structuring of escape tactics in lizard communities.
The influence of exercise on foot perfusion in diabetes
Authors: Williams D. T. , Harding K. G. , Price P. E. 
Published: June 2007

AbstractAims  Diabetic foot disease is associated with both macro‐ and microvascular disease. Exercise has both positive and negative effects on the perfusion of lower limbs with peripheral arterial occlusive disease (PAOD). We aimed to measure changes in foot perfusion following a brief period of lower‐limb exercise in individuals with and without Type 2 diabetes and non‐critical PAOD.Methods  Subjects were allocated to groups according to the presence or absence of diabetes, PAOD on colour duplex imaging and clinically detectable peripheral neuropaÍthy. Transcutaneous oxygen tension (TcPO2), transcutaneous carbon dioxide tension (TcPCO2), ankle‐brachial pressure indices, toe pressures and toe‐brachial pressure indices (TBI) were measured.Results  One hundred and sixteen limbs were studied in 61 subjects. Post‐exercise, toe pressure and TBI increased in the non‐diabetic group with arterial disease, but not in the groups with diabetes. Foot TcPO2 values increased in groups with diabetes and TcPCO2 decreased in all groups with arterial disease. Increased chest TcPO2 and decreased TcPCO2 were demonstrated in the groups with diabetes.Conclusions  Elevations in foot TcPO2 and reductions in TcPCO2 indicate improved cutaneous perfusion response to local heating post‐exercise. Elevated toe pressures in the non‐diabetes group suggest that improved perfusion may be associated with enhanced lower limb macrovascular haemodynamics. However, improvements in TcPO2 and TcPCO2 at foot and chest sites in diabetes imply a global change in cutaneous perfusion. The results suggest that brief exercise results in an improvement in cutaneous perfusion in non‐critical PAOD, particularly in individuals with diabetes.
Oral and general health behaviours among Chinese urban adolescents
Authors: Petersen Poul Erik , Jiang Han , Peng Bin , Tai Bao Jun , Bian Zhuan 
Published: June 2007

Abstract –  Objectives:  The objectives of this study were to measure the association of general and oral health‐related behaviours with living conditions and to explore the interrelationships between general and oral health‐related behaviours in Chinese urban adolescents.Methods:  A cross‐sectional survey of 2662 adolescents was conducted in eight Chinese provincial capitals. The response rate was 92%. The study population was selected through multistage cluster sampling and comprised three age groups: 11, 13 and 15 years. Data on oral and general health, lifestyles as well as living conditions were collected by means of self‐administered structured questionnaires. Several additive indices were constructed from answers to the questions on specific behaviour, and participants were categorized according to scores on each component of health‐related behaviour for statistical analyses by frequency distributions, regression analyses and factor analyses.Results:  Oral health‐related behaviours among adolescents were associated with socioeconomic status of parents, school performance and peer relationships. The odds of a dental visit was 0.63 in adolescents of poorly educated parents and the corresponding figure for regular oral hygiene practices was 0.62. Odds of tobacco use was 3 for adolescents with poor performance in school while odds of consuming sugary foods/drinks was 1.3. Adolescents with high levels of preventive oral health practices also demonstrated general health‐promoting behaviours. In factor analysis of general and oral health‐related behaviours, three factors were isolated: (a) risk behaviours (loadings 0.48–0.66), (b) health‐promoting behaviours (loadings 0.60–0.64) and (c) help‐seeking behaviours (loadings 0.56–0.67).Conclusion:  The findings support a multidimensional model of health behaviour. Several approaches and multiple methods should be applied in oral health education in order to modify behaviours that affect oral health.
Children's Expectations of Pain, Perceptions of Analgesic Efficacy, and Experiences With Nonpharmacologic Pain Management Strategies at Home Following Tonsillectomy
Authors: Sutters Kimberly A. , Savedra Marilyn C. , Miaskowski Christine , Holdridge‐Zeuner Danielle , Waite Steven , Paul Steven M. , Lanier Brent 
Published: June 2007

PURPOSE.  To document children's (ages 6–15 years) descriptions of their pain management at home following tonsillectomy. DESIGN AND METHODS.  Audio‐taped interviews of 80 children were transcribed and coded. Data for each response category were tabulated. RESULTS.  Children reported they had more pain after surgery than expected, the pain medicine helped to take their pain away, taking the pain medicine was associated with a negative response by some children, and cold liquids/food by mouth provided pain relief. PRACTICE IMPLICATIONS.  Findings provide insight into children's perspective of pain management at home following tonsillectomy and methods for relieving their pain.
Totalsynthese komplexer Cyclotryptaminalkaloide: stereokontrollierter Aufbau quartärer Kohlenstoffstereozentren
Authors: Steven Alan , Overman Larry E. 
Published: June 2007

AbstractDie Cyclotryptamine sind eine Familie von Alkaloiden mit sehr unterschiedlichen biologischen Aktivitäten. Die komplexeren Mitglieder dieser Naturstoffklasse sind durch benachbarte quartäre Kohlenstoffzentren charakterisiert und wegen der schwierig aufzubauenden, oligomeren Polyindolinstruktur schwer zugänglich. In den letzten Jahren konnten wir eine Reihe von Methoden entwickeln, die einen einfachen Zugang zu Polyindolinen ermöglichen; einige dieser Methoden nutzen Palladiumkatalysatoren zum Aufbau von Kohlenstoff‐Kohlenstoff‐Bindungen mit beeindruckenden Regio‐ und Stereoselektivitäten. In diesem Aufsatz schildern wir die Entwicklung eines Repertoires an Synthesemethoden und deren Anwendung in den Totalsynthesen einiger strukturell komplexer Cyclotryptamine. Insbesondere zeigen wir auf, wie es gelingen kann, mithilfe asymmetrischer Katalysen komplexe, hochfunktionalisierte Moleküle aufzubauen.
Quantitative Separation of As(III) and As(V) from a Synthetic Water Solution Using Ion Exchange Columns in the Presence of Fe and Mn Ions
Authors: Mondal Prasenjit , Balomajumder Chandrajit , Mohanty Bikash 
Published: June 2007

AbstractThe quantitative separation of As(III) from a water sample containing As(III) and As(V) in the presence of Fe and Mn in an ion exchange resin (AG1 X8) column for the speciation of arsenic is described. Individual and combined effects of Fe and Mn on the separation of As(III) from the solution have been studied separately. In absence of Fe and Mn, the ratio between the As(T) concentration in the eluent and the As(III) concentration in the original sample has been found to be 0.9717 under optimum process conditions. The presence of Fe(II) in the water sample increased the As(T) concentration in the eluent whereas Mn(II) decreased it. Combined effects of Fe and Mn on the percentage increment in the eluent arsenic concentration have been expressed by additive and interactive models. The interactive model has been developed by a statistical software with a 95 % confidence level. In most of the cases the error on the determination of the As(III) concentration had a minimum when using the interactive model.
Cost‐effectiveness of switching to exemestane versus continued tamoxifen as adjuvant therapy for postmenopausal women with primary breast cancer
Authors: Risebrough Nancy A. , Verma Shailendra , Trudeau Maureen , Mittmann Nicole 
Published: June 2007

AbstractBACKGROUND.Sequential tamoxifen/exemestane therapy reportedly improves disease‐free survival in women with primary breast cancer compared with continued tamoxifen therapy. The objective of the current study was to assess the cost‐effectiveness of switching to exemestane after 2 to 3 years of tamoxifen versus continued tamoxifen in postmenopausal women with primary breast cancer for a total of 5 years of adjuvant therapy.METHODS.A Markov model based on the Intergroup Exemestane Study (IES) population compared switching to exemestane versus continued tamoxifen for 2.5 years of therapy and 5 years of postadjuvant therapy follow‐up. Disease progression and hazards ratios (HR) for recurrence and survival were determined from datasets (IES and the Surveillance, Epidemiology, and End Results program of the National Cancer Institute) and from the published literature. An expert panel validated treatment patterns, outcomes, and resource utilization. Direct medical costs were included based on published sources. Cost‐effectiveness ratios were determined, and extensive sensitivity analyses were conducted.RESULTS.Exemestane was found to be more effective than tamoxifen alone with regard to disease‐free survival (2.6% absolute improvement), life‐years gained (0.1028 LY), and quality‐adjusted life‐years gained (0.1195 QALY), at an additional cost of Can$2889 per person over 7.5 years. Incremental cost‐effectiveness ratios were Can$28,119/LY gained and Can$24,185/QALY gained. The model was most sensitive to distant recurrence HR but was robust to variations in clinical, cost, and utility parameters.CONCLUSIONS.Switching to adjuvant exemestane after 2 to 3 years of tamoxifen is cost‐effective in postmenopausal women with primary breast cancer. Cancer 2007. © 2007 American Cancer Society.
Influence of buffer substances and urea on the β‐cyclodextrin‐mediated chiral separation of dipeptides in CE
Authors: Hammitzsch‐Wiedemann Manuela , Scriba Gerhard K. E. 
Published: June 2007

AbstractThe influence of buffering substances and urea on the β‐CD‐mediated chiral separations of the dipeptides Ala–Phe and Ala–Tyr was studied in the pH range of 2.5–3.8. Only minor effects of the buffer substances on the chiral separation selectivity α were observed at a β‐CD concentration of 15 mg/mL. In contrast, the selectivity improved at pH 2.5 but decreased at pH 3.8 upon the addition of 2 M urea. Complexation by β‐CD resulted in a shift of the pKa values toward higher values which was more pronounced for the DD‐enantiomers of both dipeptides than for the LL‐enantiomers. Addition of urea further increased the pKa shift. The consequence of this pKa shift is an increase of the fraction of the protonated, positively charged form of the peptides which explained the improved chiral separation at pH 2.5 and the reduced selectivity at pH 3.8. A pKa shift by the addition of urea was also observed for N‐tert‐butyloxycarbonyl phenylalanine (BOC‐Phe) as a model compound that is strongly complexed by β‐CD. This effect was not stereospecific. Addition of urea resulted in a decrease of the apparent complexation constants between β‐CD and the BOC‐Phe enantiomers to the same extent but this did not affect the separation selectivity α. For chiral separations that display strong pH dependence such as peptide enantioseparations close to the pKa values of the compounds, urea may not solely be regarded as a solubility enhancer for β‐CD but may also influence the separation.
Cytoprotective effects of anthocyanins and other phenolic fractions of Boysenberry and blackcurrant on dopamine and amyloid β‐induced oxidative stress in transfected COS‐7 cells
Authors: Ghosh Dilip , McGhie Tony K , Fisher Derek R , Joseph James A 
Published: June 2007

AbstractThere is growing interest both from consumers and researchers in the role that berries play in human health. In the experiments reported here, we assessed the ability of anthocyanins and phenolic fractions of Boysenberry and blackcurrant to ameliorate the deleterious effect of the amyloid β25–35 (100 µmol L−1, 24 h) and dopamine (1 mmol L−1, 4 h) on calcium buffering (recovery) of M1 muscarinic receptor‐transfected COS‐7 cells. Cell viability was also studied. Our results demonstrate that extracts of Boysenberry and blackcurrant showed significant protective effect and restored the calcium buffering ability of cells that had been subjected to oxidative stress induced by dopamine and the amyloid β25–35. Blackcurrant polyphenolics showed slightly higher protective effect against dopamine, whereas Boysenberry polyphenolics had a higher effect against the amyloid β25–35. In viability studies, all extracts showed significant protective effects against dopamine and amyloid β25–35‐induced cytotoxicity. Our results provide further evidence for the protective effects of berries against the neurotoxic effect of dopamine and amyloid β25–35 in brain cells. Copyright © 2007 Society of Chemical Industry
The influence of medication beliefs and other psychosocial factors on early discontinuation of disease‐modifying anti‐rheumatic drugs
Authors: Wong M. , Mulherin D. 
Published: June 2007

AbstractObjective: Although drug survival time might be a better measure of clinical effectiveness than drug adherence, there is little research literature in this area, in particular about the influence of medication beliefs and psychosocial factors. This study aimed to investigate the above relationships using patients who were newly diagnosed with rheumatoid arthritis (RA).Methods: Sixty‐eight RA patients starting their first disease‐modifying anti‐rheumatic drug (DMARD) were interviewed shortly after initiating therapy, and then one year later. Before each meeting, patients were asked to complete a set of questionnaires, including Beliefs about Medication, Spielberger State‐Trait Anxiety Inventory – Short Form, the modified Stanford Health Assessment Questionnaire, Beck Depression Inventory‐1 and the Significant Others Scale. Relevant sociodemographic background, disease activity and drug history were obtained. Clinical measures such as grip strength and joint count were assessed.Results: A stepwise logistic regression analysis was applied to two patient groups: those who continued taking their DMARD one year later, and those who did not. No significant difference between the groups for levels of disability and disease activity were found. Only age and anxiety emerged as significant predictors of drug discontinuation at 52 weeks.Conclusions: Contrary to expectation, this study demonstrated that older and less anxious patients were more likely to discontinue taking their initial DMARD within the first year. The study may have implications for counselling older and less anxious patients prior to DMARD therapy. However, there are limitations in generalizing the results because of the small population sample. It also did not take into account drug intolerance as a pertinent factor for early drug discontinuation. Copyright © 2007 John Wiley & Sons, Ltd.