bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological variation of asymmetric dimethylarginine and related arginine metabolites and analytical performance goals for their measurement in human plasma
Authors: Blackwell S. , O’Reilly D. St. J. , Talwar D. 
Published: May 2007

AbstractBackground  Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of nitric oxide synthase which is believed to be a cause of endothelial dysfunction and has been shown to predict the occurrence of acute coronary events. Data regarding the biological variation of arginine and its methylated derivatives are conspicuously absent from the literature. Such data are important in setting analytical quality specifications, assessing the utility of population reference intervals and assessing the significance of changes in serial results from an individual.Materials and methods  Arginine, homoarginine, ADMA and symmetric dimethylarginine (SDMA) are measured in plasma by high performance liquid chromatography. Twelve healthy volunteers underwent weekly blood sampling for 20 weeks in order to determine the intra‐ and inter‐individual biological variation of these analytes, from which analytical quality specifications, indices of individuality (II) and reference change values (RCV) are derived. Plasma samples from 100 healthy individuals were obtained in order to determine population reference intervals.Results  ADMA and symmetric dimethylarginine (SDMA) exhibit low intra‐individual biological variation of 7·4% and 5·8%, respectively, imposing desirable imprecision goals (CVA) of ≤ 3·7% and 2·9% for these analytes. The described methodology achieves these goals, with analytical CVs of < 3·5% for all analytes. Goals for bias and total error were 3·1–10·1% and 7·2–16·0%, respectively. Reference intervals for ADMA and SDMA were 0·29–0·63 µmol L−1 and 0·24–0·55 µmol L−1, but have IIs < 1. RCVs were at least 20% for all analytes studied.Conclusions  Dimethylarginine concentrations are tightly controlled in health, with the result that imprecision goals for laboratory methods require to be low. Relatively large differences are required between serial results to denote a significant change. Population reference intervals for dimethylarginines are likely to be of limited value in detecting ‘abnormality’ in an individual from a single result.
Low‐cycle fatigue of NiTi rotary instruments of various cross‐sectional shapes
Authors: Cheung G. S. P. , Darvell B. W. 
Published: May 2007

AbstractAim  To compare the low‐cycle fatigue (LCF) behaviour of some commercial NiTi instruments subjected to rotational bending, a deformation mode similar to an engine‐file rotating in a curved root canal, using a strain‐life analysis, in water.Methodology  A total of 286 NiTi rotary instruments from four manufacturers were constrained into a curvature by three rigid, stainless steel pins whilst rotating at a rate of 250 rpm in deionized water until broken. The number of revolutions was recorded using an optical counter and an electronic break‐detection circuit. The surface strain amplitude, calculated from the curvature (from a photograph) and diameter of the fracture cross‐section (from a scanning electron micrograph), was plotted against the number of cycles to fracture for each instrument. A regression line was fitted to the LCF lives for each brand; the value was compared with that of others using one‐way analysis of variance (anova). The number of crack origins observed on the fractographic view was examined with chi‐square for differences amongst various groups.Results  A linear strain‐life relationship, on logarithmic scales, was obtained for the LCF region with an apparent fatigue‐ductility exponent ranging from −0.40 to −0.56. The number of crack‐initiation sites, as observed on the fracture cross‐section, differed between brands (χ2, P < 0.05), but not LCF life (one‐way anova, P > 0.05).Conclusions  The LCF life of NiTi instruments declines with an inverse power function dependence on surface strain amplitude, but is not affected by the cross‐sectional shape of the instrument.
Bond strength between fibre posts and composite resin cores: effect of post surface silanization
Authors: Wrbas K. T. , Schirrmeister J. F. , Altenburger M. J. , Agrafioti A. , Hellwig E. 
Published: May 2007

AbstractAim  To evaluate the tensile bond strength between two different composite resin cores and (ClearfilTMCore, MultiCore® Flow) and fibre posts (DT Light Post®), with and without silanization of the post surface.Methodology  Forty fibre posts were shortened to a length of 15 mm. Specimens were then produced by covering the upper 3 mm of the posts with standardized composite core build‐ups. The bonding surfaces of twenty posts were treated with silane coupling agent (Monobond‐S). Four experimental groups were formed: G1: ClearfilTMCore; G2: Monobond‐S + ClearfilTMCore; G3: MultiCore® Flow; G4: Monobond‐S + MultiCore® Flow. Each post was positioned upright in a post centric device with moulds to ensure standardized shapes of the abutments. After tensile bond strength testing, the type of failure at the interface was determined. The results obtained were compared using an unpaired sample t‐test.Results  The mean tensile bond strengths and standard deviations were [MPa] 10.08 ± 0.92 for ClearfilTMCore, 10.47 ± 1.05 for ClearfilTMCore + silane; 6.65 ± 0.79 for MultiCore® Flow and 6.91 ± 0.83 for MultiCore® Flow + silane. Statistical analysis revealed that ClearfilTMCore achieved significantly higher bond strengths than MultiCore® Flow (P < 0.0001). Post silanization had no significant effect. All tested specimens had an adhesive failure mode.Conclusion  Type of composite had a significant effect on tensile bond strength. Silanization of fibre post surfaces had no effect on core retention.
A collagen ‘bio‐molecular film’ex vivo model to evaluate the efficacy of dynamic irrigation using the RinsEndo® system
Authors: McGill S. , Gulabivala K. , Ng Y.‐L. 
Published: May 2007

Aim  To evaluate the efficacy of three irrigation protocols using a model consisting of a standard collagen film coating the root canal walls of extracted teeth.Methodology  Thirty human teeth with single straight canals were randomly allocated to three groups for static (n = 10), manual dynamic (n = 20) or automated dynamic (n = 10) irrigation. The root canals were prepared to apical size 40 with a 0.08 taper. The teeth were split longitudinally to give two halves and stained collagen was applied to the canal surfaces in a standard manner. The re‐assembled teeth were irrigated using one of the protocols. Digital images were taken of the canal surfaces before and after irrigation with 18 mL of NaOCl. Static irrigation consisted of simple placement of an irrigation needle (gauge 30) in a fixed orientation 4 mm or 10 mm short of the working length. Manual dynamic irrigation consisted of push–pull agitation of the placed irrigant with a well‐fitting, tapered gutta‐percha point. Automated dynamic irrigation was carried out using the RinsEndo® system. The percentage canal surface coverage with stained collagen was calculated using a software package (ipWin4®). The data were analyzed using paired‐t tests and GEE linear regression models.Results  The area of canal covered with stained collagen was significantly (P < 0.001) less (21% or 16%, respectively) after manual or automated dynamic irrigation compared with static irrigation. However, the RinsEndo® system was significantly (P = 0.037) less effective (5%) than manual dynamic irrigation. The ‘corono‐apical level of canal’ and the ‘depth of needle tip penetration’ emerged as significant factors influencing outcome of irrigation. Residual collagen was least evident in the middle third, followed by apical and then coronal thirds. Deeper penetration of the needle tip resulted in 7.5% (P < 0.001) more effective collagen removal. The orientation of the side‐port of the irrigation needle was not a significant factor (P = 0.051).Conclusions  Automated dynamic irrigation using RinsEndo® system was significantly more effective (16%) in removing stained collagen from the root canal than static irrigation. However, it was significantly less effective (5%) than manual dynamic irrigation. Irrigation was more effective (7%) when the needle was placed closer to the apex.
Testosterone decreased urinary‐frequency in nNOS‐deficient mice
Authors: Muto Satoru , Yasuda Mitsuko , Kamiyama Yutaka , Ide Hisamitsu , Horie Shigeo 
Published: May 2007

SummaryTo observe the effect of testosterone on the frequency of urination in mice lacking neuronal nitric oxide synthase (nNOS−/−), we compared the urination patterns between unanaesthetized male wild‐type (n = 27) and nNOS−/− mice (n = 50) with or without testosterone treatment. Compared with wild‐type mice, nNOS−/− mice showed a greater frequency of urination during a 24‐h observation period (3.0 vs. 5.4 times/day, p < 0.0001) without any significant difference in the total voided volume or the functional voiding capacity. While testosterone treatment did not affect the urination patterns in wild‐type, it decreased the daytime frequency of urination (5.4 vs. 3.7 times, p = 0.0198) and the nighttime urination (4.4 vs. 2.9 times, p = 0.039) in nNOS−/− mice. The nNOS−/− mice can be a useful animal model for urinary frequency. Testosterone improved the functional abnormalities in the voiding of nNOS−/− mice.
Occupational health nurses’ perceptions of their current and future roles
Authors: Mellor Gary , St John Winsome 
Published: May 2007

Abstract Title. Occupational health nurses’ perceptions of their current and future roles Aim.  This paper is a report of an investigation of Australian occupational health nurses’ perceptions of their current and future roles.Background.  Occupational health nurses are expected to engage in a variety of traditional curative activities as well as emergent role activities focusing on injury prevention, health promotion, wellness, management and research. However, little is known about the importance they place on traditional and emergent activities in both current and future practice.Method.  The 416 members of the Australian College of Occupational Health Nurses were asked in 2002–03 to complete a questionnaire with items based on the College's areas of practice. The items related to perceived importance and time dedicated to traditional and contemporary role activities. One hundred completed questionnaires were returned, but only 93 were suitable for analysis (response rate 22%).Findings.  Currently, Australian occupational health nurses engage in traditional curative and emergent wellness, management and research activities, but traditional activities dominate their work. Participants perceived that in the future activities related to wellness, management and research will be more important to their practice and that they will need to devote more time to them.Conclusion.  Education programmes will need to address specifically the knowledge and skills required for wellness‐based models of practice in occupational health nursing, as well as research and negotiating skills for working with others in the workplace.
Does obesity prevent the needle from reaching muscle in intramuscular injections?
Authors: Zaybak Ayten , Güneş Ülkü Yapucu , Tamsel Sadık , Khorshid Leyla , Eşer İsmet 
Published: May 2007

Abstract Title. Does obesity prevent the needle from reaching muscle in intramuscular injections? Aim.  This paper is a report of a study to measure subcutaneous tissue thickness at the dorsogluteal and ventrogluteal sites and to determine optimal needle length for dorsogluteal and ventrogluteal intramuscular injections in adults with a body mass index of more than 24·9 kg/m2.Background.  Problems can arise if drugs designed to be absorbed from muscle are only delivered into subcutaneous tissue. Increasing obesity in all developed and many developing countries makes this an increasing concern.Method.  Ultrasound measurements were made of the subcutaneous tissue of overweight, obese and extremely obese people at the dorsogluteal and ventrogluteal sites with the probe held at a 90° angle to the plane of the injection site. Subcutaneous tissue thickness was measured in 119 adults whose body mass index was ≥25 kg/m2. The data were collected in 2005–2006.Results.  Mean subcutaneous tissue thickness at the dorsogluteal site was 34·5 mm for overweight adults, 40·2 mm for obese adults and 51·4 mm for extremely obese adults, and at the ventrogluteal site was 38·2 mm for overweight adults, 43·1 mm for obese adults and 53·8 mm for extremely obese adults.Conclusion.  Intramuscular injections administered at the dorsogluteal site in 98% of women and 37% of men, and at the ventrogluteal site in 97% of women and 57% of men, would not reach the muscles of the buttock. A needle longer that 1·5 inches should be used in women whose body mass index is more than 24·9 kg/m2, the dorsogluteal site may be used in all overweight and obese men, and the ventrogluteal site may be used in overweight men only.
Using the Care Dependency Scale for fall risk screening
Authors: Mertens Elke I. , Halfens Ruud J.G. , Dassen Theo 
Published: May 2007

Abstract Title. Using the Care Dependency Scale for fall risk screening Aim.  This paper is a report of a study conducted to estimate the sensitivity and specificity of the Care Dependency Scale as a measure of risk of falling for individuals in hospital and nursing home settings.Background.  Falls and their consequences are common problems in hospitals and nursing homes and nurses should assess the potential risks of their patients. Items in fall risk scales resemble a general nursing assessment, which leads to redundant assessment procedures. It would be beneficial to have a single generic instrument for general assessment and fall risk screening.Methods.  Standardized questionnaires were used in a cross‐sectional study in 2004 and data were gathered from 9943 German nursing home residents and hospital patients (response rate 77·1%). Sensitivity and specificity of all Care Dependency Scale scores were calculated for fall risk. Relationships between the 15 scale items and falls were described using odds ratios and logistic regression analysis.Findings.  Patients with falls in hospitals were more care dependent than those without falls. Sensitivity and specificity values showed that with the Care Dependency Scale a differentiation is possible between the falls group and the no‐falls group. High odds ratios and logistic regression analysis suggest that the Care Dependency Scale item ‘Avoidance of danger’ indicated fall risk. Nursing home residents with and without falls had similar care dependency scores.Conclusion.  Nursing assessment in hospitals could be simplified by using the Care Dependency Scale for fall risk screening. Its value in fall risk screening in nursing homes requires further testing.
Spheres of influence or autonomy? A discourse analysis of the introduction of Nurse Practitioners in rural and remote Australia
Authors: Turner Clare , Keyzer Dirk , Rudge Trudy 
Published: May 2007

Abstract Title. Spheres of influence or autonomy? A discourse analysis of the introduction of Nurse Practitioners in rural and remote Australia Aim.  This paper is a report of a study to examine the social discourses of nursing within health care as these produce understandings about autonomy for Nurse Practitioners, where autonomy refers to the ability of Nurse Practitioners to practise as professionals in their own right.Background.  Nurse Practitioners were recently introduced to the nursing career pathways in Australia. Despite a plethora of international information, the role implementation in rural and remote Australia is slow with a number of influences emerging to hinder progress.Method.  Critical discourse analysis was used to examine the differences between policy and the reality of implementation. The notion of autonomy was used to explore texts in policy documents relating to Nurse Practitioner authorization and published between 1995 and 2006, and these were compared with the experiences of nurses working in Nurse Practitioner positions.Findings.  Policy texts indicate support for advanced practice and the autonomy of Nurse Practitioners. The process for authorization; however, has constraints which support nurses’ progress but also hinder it. Subsequent acceptance of Nurse Practitioners has also been problematic as colleagues struggle to understand the role within the current healthcare system.Conclusions.  There is a significant gap between the rhetoric of policy and the implementation of Nurse Practitioner roles in rural and remote Australia. Whilst policy supports the notion of autonomy, the experiences of nurses indicate a mere shift in the traditionally‐accepted boundaries of nurses’ roles. Evidence from the United Kingdom and United States of America suggests that the findings in this study are relevant internationally as well as nationally.
Effects of ecogeographic variables on genetic variation in montane mammals: implications for conservation in a global warming scenario
Authors: Ditto Amy M. , Frey Jennifer K. 
Published: May 2007

AbstractAim  Evolutionary theory predicts that levels of genetic variation in island populations will be positively correlated with island area and negatively correlated with island isolation. These patterns have been empirically established for oceanic islands, but little is known about the determinants of variation on habitat islands. The goals of this study were twofold. Our first aim was to test whether published patterns of genetic variation in mammals occurring on montane habitat islands in the American Southwest conformed to expectations based on evolutionary theory. The second aim of this research was to develop simple heuristic models to predict changes in genetic variation that may occur in these populations as a result of reductions in available mountaintop habitat in response to global warming.Location  Habitat islands of conifer forest on mountaintops in the American Southwest.Methods  Relationships between island area and isolation with measures of allozyme variation in four species of small mammal, namely the least chipmunk (Tamias minimus), Colorado chipmunk (Tamias quadrivittatus), red squirrel (Tamiasciurus hudsonicus), and Mexican woodrat (Neotoma mexicana), were determined using correlation and regression techniques. Significant relationships between island area and genetic variation were used to develop three distinct statistical models with which to predict changes in genetic variation following reduction in insular habitat area arising from global warming.Results  Patterns of genetic variation in each species conformed to evolutionary predictions. In general, island area was the most important determinant of heterozygosity, while island isolation was the most important determinant of polymorphism and allelic diversity. The heuristic models predicted widespread reductions in genetic variation, the extent of which depended on the population and model considered.Main conclusions  The results support a generalized pattern of genetic variation for any species with an insular distribution, with reduced variation in smaller, more isolated populations. We predict widespread reductions in genetic variation in isolated populations of montane small mammals in the American Southwest as a result of global warming. We conclude that climate‐induced reductions in the various dimensions of genetic variation may increase the probability of population extinction in both the short and long term.
The phylogeography of palm cockatoos, Probosciger aterrimus, in the dynamic Australo‐Papuan region
Authors: Murphy Stephen A. , Double Michael C. , Legge Sarah M. 
Published: May 2007

AbstractAims  We aimed to investigate the effects of historical land–sea boundary and vegetation dynamics in the Australo‐Papuan region on the genetic structure of palm cockatoo populations. In doing so, we also sought to clarify the intraspecific taxonomic status of palm cockatoos, and to examine the potential conservation implications of our results.Location  New Guinea and northern Australia.Methods  We examined mtDNA (domain III, control region) genetic structure in 71 palm cockatoos from 17 locations across their Australo‐Papuan range.Results  Twenty polymorphic sites over 242‐base pairs defined 12 haplotypes that were arranged in a 95% confidence parsimony network of six one‐step clades. Half of these were linked in one clade that included birds from eastern New Guinea–Australia, and the other half included birds from western New Guinea. Nested clade analyses revealed strong and significant genetic structure between these two clades. The average nucleotide divergence between eastern and western birds is c. 3.3%. Within the western clade there was a non‐random distribution of haplotypes according to sampling location alone, but the locations did not cluster significantly, probably due to low sample sizes. A non‐random distribution of haplotypes emerged within one of the one‐step clades from the east of the range (once rare haplotypes were removed), although the historic mechanism that may have created this pattern is unclear. The underlying low nucleotide divergence (0.39%) among haplotypes within the eastern clade suggests relatively recent common ancestry.Main conclusions  Our results suggest genetic isolation of the eastern and western clades sometime during the Pleistocene. The continual reappearance of land bridges associated with Pleistocene glacio‐eustatic cycles within the eastern part of the range provides an explanation for our results. We suggest that the occurrence of two deep marine troughs maintained a narrow mountainous barrier between eastern and western birds throughout much of the Pleistocene at a time when extensive land bridges formed elsewhere in the species’ range, and that this has maintained their genetic distinctiveness. Our results provide little support for the current accepted subspecies; the western clade is roughly congruent with Probosciger aterrimus goliath (with caveats), but the otherwise unstructured small genetic distances cast considerable doubt on the remaining subspecies. The eastern and western lineages are endemic to each area and should therefore be considered for independent conservation status and management.
Well‐being of institutionalized elders after Yang‐style Tai Chi practice
Authors: Chen Kuei‐Min , Hsu Ya‐Chuan , Chen Wen‐Ting , Tseng Hung‐Fu 
Published: May 2007

Aims and objectives.  The purpose of this study was to examine the effects of Tai Chi on the physical and psychological well‐being of elders who resided in long‐term care facilities.Background.  The beneficial effects of Tai Chi on elders’ well‐being have been well‐documented; however, most of the studies focused on community‐dwelling or healthier elders.Design and methods.  In this longitudinal, time‐series, quasi‐experimental study, a convenience sample of 28 institutionalized elders was recruited. A six‐month Yang‐style Tai Chi intervention was administered twice a week for 60 minutes per practice. The well‐being outcome variables, including physical and mental health status, blood pressure, quality of sleep, occurrence of falls and fear of falling, were measured before the intervention and then at one‐month, two‐month, three‐month and six‐month intervals.Results.  Results indicated that the physical health status and social functioning of frail elders were significantly improved after Tai Chi practice [F(4,24) = 3·42, p = 0·038; F(4,24) = 9·66, p = 0·001 respectively].Conclusions.  Tai Chi practice is beneficial for frail older people.Relevance to clinical practice.  The findings provide a basis for using Yang‐style Tai Chi as a floor activity in long‐term care facilities to promote the well‐being of the older residents.