bluuebunny/crossref_metadata_2025 huggingface dataset:
Bone resorption and renal calcium reabsorption in renal cell carcinoma‐bearing mice: the effects of bisphosphonate
Authors: Weissglas Max , Löwik Clemens , Schamhart Denis , Theuns Harry , Kurth Karl‐Heinz , Papapoulos Socrates
Published: April 2007

OBJECTIVE

To examine the contribution of the skeleton and the kidney to the development of humoral hypercalcaemia of malignancy (HHM) in a mouse model of HHM treated with a potent bisphosphonate.

MATERIALS AND METHODS

Mice bearing the human RCC cell line RC‐9 were treated with bisphosphonate (subcutaneous, 0.25 mg/kg body weight olpadronate) or saline solution. Treatment was initiated at a tumour volume (TV) of ≈100 mm3 and 500 mm3, and the mice were monitored for ≈4 weeks. Serum calcium and phosphate concentrations and trabecular bone volume (TBV) were assessed during and/or after treatment.

RESULTS

Athymic mice implanted with the RCC RC‐9, developed severe hypercalcaemia and bone resorption. During tumour growth the mean (sd) serum calcium concentration increased to 4.1 (0.3) mmol/L, and phosphate decreased to 1.6 (0.3) mmol/L, vs 2.3 (0.1) and 2.9 (0.4) mmol/L in controls, respectively. TBV decreased from 8.7 (1.8)% in mice with no tumour, to 5.3 (2.7)% in RC‐9‐bearing mice. Olpadronate initiated at a Tv of 100 mm3 prevented the loss of bone induced by RCC RC‐9 cells, with a TBV of 12.8 (2.1)%, but the development of hypercalcaemia was unaffected. Olpadronate treatment at a TV of 500 mm3 did not influence the development of hypercalcaemia and did not protect against bone resorption. Kinetic monitoring showed an identical rate of tumour growth in the presence or absence of bisphosphonate, while under both conditions there was a tumour load‐dependent increase in calcium concentration.

CONCLUSIONS

Bisphosphonate can prevent parathyroid hormone‐related peptide (PTHrP)‐mediated bone resorption when administered during the early phase of renal tumour growth, but has no effect on the tumour‐induced development of hypercalcaemia, indicating a primary role for renal tubular reabsorption of calcium in the kidney by PTHrP in HHM.
Characteristics and response to antiretroviral therapy of HIV‐1‐infected patients born in Africa and living in France
Authors: Breton G , Lewden C , Spire B , Salmon D , Brun‐Vézinet F , Duong M , Allavena C , Leport C , Salamon R ,   the APROCO COPILOTE ANRS CO8 Study Group
Published: April 2007

Background

The world‐wide AIDS epidemic is reflected in Western Europe in an increasing number of HIV‐infected persons who originate from Africa. We describe the characteristics and response to antiretroviral therapy (ART) of HIV‐infected patients born in Africa and living in France.

Methods

Analysis of data from the (Anti PROtéase COhorte APROCO) cohort study of HIV‐infected patients initiating ART was carried out. Included in the study were 90 patients born in sub‐Saharan Africa, 53 in North Africa and 771 in metropolitan France.

Results

At baseline, there was a higher proportion of women and of the heterosexual transmission route of infection among patients born in sub‐Saharan Africa, a higher proportion of injecting drug users among patients born in North Africa and a higher frequency of unemployment and of unstable housing conditions among patients born in both sub‐Saharan and North Africa as compared with patients born in France. The median CD4 cell count was lower in patients born in both sub‐Saharan and North Africa (sub‐Saharan Africa: 197 cells/μL; North Africa: 222 cells/μL) than in patients born in France (307 cells/μL). Median HIV‐1 viral loads were similar. After a median follow‐up time of 36 months (2506 patient‐years), the Kaplan–Meier estimations of probability of survival without new AIDS‐defining events were not different. After 36 months of ART, in multivariate analysis, median CD4 cell count, CD4/CD8 ratio and viral load were not statistically different according to birthplace, but the median CD4 percentage was lower in patients born in both sub‐Saharan and North Africa. The adherence profiles were similar.

Conclusions

Although clinical response and adherence to ART did not appear to differ in patients according to their birthplace, the reasons for the more advanced HIV infection observed at ART initiation among patients born in Africa should be further investigated.
National review of first treatment change after starting highly active antiretroviral therapy in antiretroviral‐naïve patients
Authors: Hart E , Curtis H , Wilkins E , Johnson M
Published: April 2007

Objectives

The aim of the study was to explore the factors surrounding modification of the first antiretroviral (ARV) regimen where drug switch occurred 3 months or more after initiation. Reference was made to the British HIV Association (BHIVA) guidelines on HIV management.

Methods

A case note and questionnaire‐based audit was carried out.

Results

Toxicity was the single most important reason for ARV change and was the only, or a contributory, cause in over half the patients. Virological failure, adherence issues, requirement for treatment simplification, and patient request were other significant reasons cited. In one‐third of those with virological failure, six or more months had elapsed between first detection and the time of switching to a new ARV regimen.

Conclusions

This audit demonstrated broad adherence to the BHIVA guidelines, although the long time before switching ARVs in the setting of virological failure was of some concern, particularly given the continuing and significant occurrence of primary ARV resistance in the UK.
Cognitive function, mood and health‐related quality of life in hepatitis C virus (HCV)‐monoinfected and HIV/HCV‐coinfected individuals commencing HCV treatment*
Authors: Thein HH , Maruff P , Krahn M , Kaldor JM , Koorey DJ , Brew BJ , Dore GJ
Published: April 2007

Objectives

The aim of the study was to examine cognitive function, mood and health‐related quality of life (HRQOL), and their interrelationships, among hepatitis C virus (HCV)‐monoinfected and HIV/HCV‐coinfected individuals.

Methods

Baseline neuropsychological and HRQOL measures of HCV‐monoinfected and HIV/HCV‐coinfected individuals commencing HCV treatment were examined from a prospective cohort study conducted between April 2003 and August 2005 in Sydney, Australia. Participants' neuropsychological performance and HRQOL were measured using computer‐based battery, Trail Making Tests (TMT), Depression Anxiety Stress Scales (DASS), the Hepatitis Quality of Life Questionnaire (HQLQ), and the Visual Analogue Scale (VAS). Neuropsychological measures of HCV‐infected patient groups were compared with those of two control groups consisting of HIV‐monoinfected and uninfected individuals.

Results

Similar cognitive function, mood and HRQOL were found in HCV‐monoinfected (n=19) and HIV/HCV‐coinfected (n=15) individuals. When compared with the HIV‐monoinfected (n=30) and uninfected control (n=30) groups, subtle cognitive impairment in attention was found in the HIV/HCV‐coinfected group (P<0.05). Twenty‐one percent of the HCV‐monoinfected group were classified as having cognitive impairment compared with 10% or less in the other groups. Sociodemographic characteristics, mood, HRQOL and HCV indices did not correlate with cognitive function.

Conclusions

Our findings indicate no statistically significant difference in neuropsychological and HRQOL impairments between HIV/HCV‐coinfected individuals with nonadvanced HIV disease and HCV‐monoinfected individuals. This lack of significant difference may relate to the relatively small study population.
Multivitamin supplementation in HIV‐positive pregnant women: impact on depression and quality of life in a resource‐poor setting
Authors: Smith Fawzi MC , Kaaya SF , Mbwambo J , Msamanga GI , Antelman G , Wei R , Hunter DJ , Fawzi WW
Published: April 2007

Objectives

The primary objective of this study was to examine the effect of vitamin supplementation on health‐related quality of life and the risk of elevated depressive symptoms comparable to major depressive disorder (MDD) in HIV‐positive pregnant women in Dar es Salaam, Tanzania.

Methods

From April 1995 to July 1997, 1078 HIV‐positive pregnant women were enrolled in a randomized controlled trial. We examined the effects of vitamin supplementation on quality of life and the risk of elevated depressive symptoms, assessed longitudinally every 6–12 months.

Results

A substantial prevalence of elevated depressive symptoms (42%) was observed in HIV‐positive pregnant women. Multivitamin supplementation (B‐complex, C and E) demonstrated a protective effect on depression [relative risk (RR)=0.78; P=0.005] and quality of life [RR=0.72 for social functioning (P=0.001) and vitality (P=0.0001); RR=0.70 for role‐physical (P=0.002)]; however, vitamin A showed no effect on these outcomes.

Conclusions

Multivitamin supplementation (B‐complex, C and E) resulted in a reduction in risk of elevated depressive symptoms comparable to MDD and improvement in quality of life in HIV‐positive pregnant women in Tanzania.
Seroprevalence of HIV infection in hospitalized paediatric patients at a tertiary care centre in western India
Authors: Shah I , Katira B
Published: April 2007

The prevalence of HIV infection in children in India is not known. In this study, a total of 270 children admitted to paediatric wards in Mumbai were screened for HIV infection by enzyme‐linked immunosorbent assay (ELISA). Eight patients (2.96%) had a positive HIV ELISA. Of these two patients (25%) were less than 15 months of old and hence HIV infection in them could not be confirmed. The prevalence of HIV was 2.3%. Three out of 11 patients with tuberculosis (27.3%) and four out of 15 patients with nutritional anaemia (26.7%) had HIV infection (P<0.0001 in each case). Vertical transmission was the cause in all children, suggesting that implementation of Prevention of Parent to Child Transmission of HIV (PPTCT) is required to reduce the rate of paediatric HIV infection.
Inhibitory quotient as a prognostic factor of response to a salvage antiretroviral therapy containing ritonavir‐boosted saquinavir. The CIVSA Study*
Authors: Mallolas J , Blanco JL , Labarga P , Vergara A , Ocampo A , Sarasa M , Arnedo M , López‐Púa Y , García J , Juega J , Guelar A , Terrón A , Dalmau D , García I , Zárraga M , Martínez E , Carné X , Pumarola T , Escayola R , Gatell JM
Published: April 2007

Background

The addition of a low dose of ritonavir to protease inhibitors (PIs) has become a widespread strategy to improve PI pharmacokinetics. As resistance is a major barrier to long‐term suppression, in salvage therapy genotype and/or phenotype scoring is currently used to predict the response. We evaluated the relationship between the saquinavir (SQV) inhibitory quotient (IQ) (virtual and genotypic) and virological response.

Methods

Eligible patients were on a PI‐containing highly active antiretroviral therapy (HAART) regimen excluding SQV and had a viral load >5000 HIV‐1 RNA copies/mL. The PI was switched to SQV/ritonavir (RTV) 1000/100 mg twice a day (bid) and the same two backbone nucleoside reverse transcriptase inhibitors (NRTIs) were maintained at least until week 4, when the resistance test results became available. Genotype and virtual phenotype were determined at baseline, while the SQV trough plasma concentration was determined at week 4.

Results

Fifty‐three patients were included in the study. Mean baseline viral load and CD4 count were 137 693 copies/mL and 263 cells/μL, respectively, the mean number of previous PIs was 2.3 and the mean number of protease gene mutations (PGMs) was 4.1. Using an on‐treatment analysis, at week 16 the mean increase in CD4 count was 70.9 cells/μL, viral load was <200 copies/mL in 17 out of 37 patients (45.9%), and 30 out of 45 patients (66.7%) were considered virological responders (VRs) (viral load <200 copies/mL or viral load declined ≥1 log10 at week 16). Median virtual phenotype was 1.3 (0.6–6.9). Baseline differences were detected between VR and non‐VR populations: the mean numbers of PGMs were 3.2 and 5.8 (P<0.05), the mean numbers of SQV‐associated mutations were 2 and 3.8 (P<0.05), and the mean CD4 counts were 365.9 and 184.3 cells/μL (P<0.05), respectively. Mean SQV trough concentrations at week 4 were 1.1 and 1.0 μg/mL (not significant), and mean virtual IQs were 0.7 and 0.1 (P<0.01), respectively. Multivariate analysis showed that baseline PGMs >5 or SQV‐associated mutations>5, virtual phenotype, baseline viral load >50 000 copies/mL, and virtual IQ <0.5, but not genotypic IQ, were the variables independently associated with non‐VR.

Conclusion

In heavily pretreated patients, the use of SQV virtual IQ or alternatively virtual phenotype, as well as PGMs, is a useful tool for the prediction of virological response.
Prediction of clinical benefits of ritonavir‐boosted TMC114 from treatment effects on CD4 counts and HIV RNA
Authors: Hill A , Montaner J , Smith C
Published: April 2007

Objective

The aim of the study was to predict reductions in progression to AIDS/death associated with the treatment benefit of antiretrovirals on CD4 counts and HIV RNA in the era of highly active antiretroviral therapy (HAART).

Design

The study design was a pooled analysis of two trials (POWER 1 and POWER 2) of optimized background treatment plus either TMC114/ritonavir (TMC114/r) or control protease inhibitor (CPI).

Methods

Across the two randomized trials (mean baseline CD4 count 114 cells/μL and HIV RNA 4.6 log10 HIV‐1 RNA copies/mL), CD4 counts rose by a mean of 98 cells/μL for TMC114/r 600/100 mg twice a day (bid) vs. 17 cells/μL for CPI at week 24; HIV RNA fell by a median of 1.90 and 0.49 log10 copies/mL in the two groups, respectively. For the CD4 categorization method, cohort data on rates of progression to AIDS/death during HAART within preset CD4 ranges were used to predict rates of progression during TMC114/r and CPI treatment. For the regression method, data from clinical endpoint trials were used to correlate historical treatment effects on HIV RNA and CD4 with clinical benefits.

Results

The CD4 categorization method predicted a 48% reduction in clinical progression to AIDS/death for TMC114/r vs. CPI. The regression method predicted a 55% reduction [95% confidence interval (CI) 45–66%] in the hazard of progression to AIDS/death based on CD4 counts, with a 47% reduction (95% CI 38–53%) predicted from effects on HIV RNA.

Conclusions

Independent methods generated similar predictions of a 47–55% reduction in progression to AIDS/death for TMC114/r vs. CPI treatment, based on the changes in CD4 counts and HIV RNA from the POWER 1 and POWER 2 trials. These methods could be used to estimate clinical benefits of other antiretrovirals.
A double‐blind, parallel‐group, placebo‐controlled, multicentre study of acetyl l‐carnitine in the symptomatic treatment of antiretroviral toxic neuropathy in patients with HIV‐1 infection
Authors: Youle M , Osio M ,   on behalf of the ALCAR Study Group
Published: April 2007

Background

Nucleoside reverse transcriptase inhibitors (NRTIs) disrupt neuronal mitochondrial DNA synthesis, resulting in antiretroviral toxic neuropathy (ATN). Acetyl‐l‐carnitine (ALCAR) enhances neurotrophic support of sensory neurones, potentially providing symptom relief and nerve regeneration.

Objective

The objective of the study was to assess the safety and efficacy compared to placebo of intramuscular ALCAR in HIV‐positive patients with symptomatic distal symmetrical polyneuropathy.

Methods

Ninety patients were enrolled and randomized to receive ALCAR [500 mg twice a day (bid); n=43] or placebo (n=47) intramuscularly twice daily for 14 days followed by 42 days of oral ALCAR 1000 mg bid. Assessment of pain was obtained using the Visual Analogue Scale (VAS), Total Symptom Score (TSS), Clinical Global Impression of Change, McGill Pain Questionnaire (MPQ), and the need for rescue analgesics.

Results

There was no statistically significant difference in changes in VAS over 14 days between groups for the intent‐to‐treat (ITT) population, but for the efficacy‐evaluable (EE) population ALCAR treatment produced a significantly greater reduction in pain compared with placebo (P=0.022). The proportion of patients with an improvement in TSS over 14 days was greater in the ALCAR group compared with the placebo group, but the differences were not statistically significant. During the open‐label phase, patients experienced an improvement in pain, as measured by the VAS, TSS and McGill Pain Questionnaire.

Conclusion

ALCAR, administered twice a day intramuscularly to HIV‐1‐infected patients with symptomatic ATN, significantly reduced weekly mean pain ratings on the VAS compared with placebo. Treatment with oral ALCAR improved symptoms for the patient group as a whole. Intramuscular and oral ALCAR was generally safe and well tolerated.
Untangling syntactic and sensory processing: An ERP study of music perception
Authors: Koelsch Stefan , Jentschke Sebastian , Sammler Daniela , Mietchen Daniel
Published: April 2007

The present study investigated music‐syntactic processing with chord sequences that ended on either regular or irregular chord functions. Sequences were composed such that perceived differences in the cognitive processing between syntactically regular and irregular chords could not be due to the sensory processing of acoustic factors like pitch repetition, pitch commonality (the major component of “sensory dissonance”), or roughness. Three experiments with independent groups of subjects were conducted: a behavioral experiment and two experiments using electroencephalography. Irregular chords elicited an early right anterior negativity (ERAN) in the event‐related brain potentials (ERPs) under both task‐relevant and task‐irrelevant conditions. Behaviorally, participants detected around 75% of the irregular chords, indicating that these chords were only moderately salient. Nevertheless, the irregular chords reliably elicited clear ERP effects. Amateur musicians were slightly more sensitive to musical irregularities than nonmusicians, supporting previous studies demonstrating effects of musical training on music‐syntactic processing. The findings indicate that the ERAN is an index of music‐syntactic processing and that the ERAN can be elicited even when irregular chords are not detectable based on acoustical factors such as pitch repetition, sensory dissonance, or roughness.
Psychomotor speed in hypertension: Effects of reaction time components, stimulus modality, and phase of the cardiac cycle
Authors: Edwards Louisa , Ring Christopher , McIntyre David , Carroll Douglas , Martin Una
Published: April 2007

Hypertension is characterized by cognitive deficits. As evidence for impaired psychomotor speed, including slower reaction times, is mixed, we aimed to provide a detailed investigation of simple reaction time in hypertension. Pre‐motor and motor reaction times were measured across the cardiac cycle in 30 hypertensives and 29 normotensives to determine the effects of phasic and tonic blood pressure on performance. Auditory, visual, and tactile simple reaction time tasks were completed with stimuli presented 0, 300, and 600 ms after the R‐wave of the electrocardiogram. Reaction times did not differ between hypertensives and normotensives. Although pre‐motor reaction times were faster during the late phase than the early phase of the cardiac cycle whereas motor reaction times were unchanged, this effect was similar for hypertensives and normotensives. No sensory‐motor deficits were evident in these hypertensives regardless of baroreceptor activity.
Ehlers–Danlos Syndrome and Anorexia Nervosa: A Dangerous Combination?
Authors: Miles Stacia C. , Robinson D. Paul , Miles Judith L.
Published: April 2007

Abstract:  A 16‐year‐old boy with anorexia nervosa and Ehlers–Danlos syndrome presented with spontaneous pneumomediastinum and bradycardia. Although prior occurrences of pneumomediastinum and visceral perforations have been reported in adolescents with isolated anorexia nervosa or Ehlers–Danlos syndrome, to our knowledge this is the first instance to be noted in a patient with both conditions. We explore several possibilities regarding the etiology of his mediastinal air, but ultimately conclude that it was the existence of Ehlers–Danlos syndrome in the presence of anorexia nervosa that led to the development of this dangerous condition.
Autosomal Recessive Cutis Laxa in Two Siblings Associated with Blue Sclera
Authors: Girisgen Ilknur , Mungan Ilke , Cakir Murat , Ersoz Safak , Okten Ayşenur
Published: April 2007

Abstract:  Cutis laxa is a clinical entity found in a heterogeneous group of genetic and acquired disorders characterized by premature aging of the skin with normal wound healing. We report two siblings born of consanguineous parents who presented with growth retardation, delayed developmental milestones, and the classical phenotypic manifestations of type 2 recessive cutis laxa. They showed remarkable blue sclera, which to our knowledge has not been reported previously in cutis laxa.
Café au Lait Macules and Juvénile Polyps
Authors: Pacheco Theresa R. , Scatena Lisa S. , Hoffenberg Edward J. , Gralla Jane , Lee Lela A.
Published: April 2007

Abstract:  Several hereditary and nonhereditary gastrointestinal tract polyposis syndromes exhibit extra‐intestinal manifestations, including cutaneous findings. However, a lack of information exists regarding cutaneous features of juvenile polyposis. Our objective was to document the prevalence of cutaneous hyperpigmented lesions in children with juvenile polyposis coli or juvenile polyposis coli and their first degree relatives. Children seen in the gastroenterology practice at The Children's Hospital in Denver, Colorado with polyps (juvenile polyposis coli, sporadic juvenile polyps, and familial adenomatous polyposis coli) and their first degree relatives were invited to participate in the study. A comprehensive skin examination was performed on those who consented to participate. We found that 8 of 14 patients (eight with juvenile polyposis coli, four with juvenile polyposis, and two with familial adenomatous polyposis coli) had at least one café‐au‐lait macule, compared with three of 27 relatives (p = 0.003). The prevalence of at least one café‐au‐lait macule in our patients (8/14 or 57.1%, CI: 28.9–82.3%) was significantly higher than the general population prevalence of 28.5% (p = 0.023). However, if the two patients with familial adenomatous polyposis coli were excluded, the comparison with the general population prevalence did not reach statistical significance (p = 0.095). The prevalence of multiple café‐au‐lait macules in our patients (4/14 or 28.6%; CI: 8.4–58.1%) was significantly higher than the general population prevalence of 5.2% (p = 0.005). A notable finding was the presence of multiple café‐au‐lait macules in 4 of 12 juvenile polyposis coli/juvenile polyposis patients. Two patients with juvenile polyposis coli also had lentigines. In this selected case series, we observed single or multiple café‐au‐lait macules in a high proportion of children with the three types of polyps. Further studies are needed to assess a possible common pathway for hamartomatous polyps and café‐au‐lait macules.
A Follow–Up of Mathematics Interventions for Secondary Students with Learning Disabilities
Authors: Maccini Paula , Mulcahy Candace A. , Wilson Michael G.
Published: April 2007

This article extends a previous review of the literature ( Maccini & Hughes, 1997 ) on mathematics interventions for secondary school students with learning disabilities (LD). A systematic review of the literature from 1995 to 2006 yielded 23 articles that met the criteria for inclusion. It was determined that a number of practices demonstrated significant gains for secondary school students with LD in math, including mnemonic strategy instruction, graduated instructional approach, cognitive strategy instruction involving planning, schema–based instruction, and contextualized videodisc instruction. We also discuss the nature and focus of math interventions and implications for both research and practice based on the findings.
Self–Regulation and Mathematics Instruction
Authors: Montague Marjorie
Published: April 2007

The purpose of this article is to provide an overview of research–based interventions that incorporate self–regulation strategies to improve mathematics performance of students with learning disabilities (LD). Self–regulation is a metacognitive function essential to academic success. Students with LD are notoriously poor at self–regulation and must be taught explicitly to monitor and control their cognitive activities as they engage in academic tasks such as mathematical problem solving. This article describes intervention studies that use self–regulation strategies to improve mathematics performance of students with LD at the elementary, middle, and secondary school levels. Several techniques to facilitate effective implementation of self–regulation instruction in the classroom are presented.
Dynamics of water use in Scotland
Authors: Moran Dominic , MacLeod Michael , McVittie Alistair , Lago Manuel , Oglethorpe David
Published: April 2007

This paper uses a variety of data sources and methodologies to construct business as usual (BAU) water‐use scenarios for the Water Framework Directive (WFD) characterisation report, a key preliminary benchmarking requirement for member states. The paper addresses the most significant water‐use sectors in Scotland over the period 2001–2015. In terms of volumetric use, our figures are dominated by the demands of electricity generation. The next highest demands come from fish farming/aquaculture, which is mostly direct abstraction. Various industrial uses are estimated to be associated with significant volumetric uses (specifically electrical and engineering, fibres and food and drink). Because of structural changes in farm support, agriculture is the only sector showing a decline. Household demand is also a highly significant use and we are able to specify the public/private breakdown of demand.
Three Concepts of Causation
Authors: Hitchcock Christopher
Published: April 2007

I distinguish three different concepts of causation: Thescientificconcept, or causal structure, is the subject of recent work in causal modeling. Thefolk attributiveconcept has been studied by philosophers of law and social psychologists. Themetaphysicalconcept is the one that metaphysicians have attempted to analyze. I explore the relationships between these three concepts, and suggest that the metaphysical concept is an untenable and dispensable mixture of the other two.
Amphibian chytridiomycosis: strategies for captive management and conservation
Authors: YOUNG S. , BERGER L. , SPEARE R.
Published: April 2007

Dramatic declines and extinctions of amphibian species have occurred worldwide over the last three decades owing to the introduction of chytridiomycosis. This emerging infectious disease is caused by the chytrid fungus Batrachochytrium dendrobatidis, a virulent water‐borne pathogen of many amphibian species. It has caused epidemic waves of high mortality as it spread through susceptible wild populations in Australia, North, Central and South America, and New Zealand, and is now endemic in surviving populations in these continents and in Europe and Africa. The prevalence of chytridiomycosis in the international amphibian trade is high and import of infected frogs into zoos has caused disease epidemics in established amphibian collections. Management of disease spread requires effective national and international quarantine and control strategies. Although B. dendrobatidis is susceptible to a range of commonly used disinfectants, there is no universally effective treatment regime for infected amphibians. Zoological institutions can play a key role in preventing pathogen spread between captive facilities, and in disease surveillance, captive‐breeding and reintroduction programmes, to limit the impact of this formidable disease on wild amphibian populations.
Reduced tear production in three canine endocrinopathies*
Authors: Williams D. L. , Pierce V. , Mellor P. , Heath M. F.
Published: April 2007

Objectives:Previous reports have suggested that hypothyroid and diabetic patients can be predisposed to keratoconjunctivitis sicca. This study aimed to measure tear production in dogs with diabetes, hypothyroidism and hyperadrenocorticism using the Schirmer tear test and to compare these results with Schirmer tear test values for a group of normal dogs.

Methods:Schirmer tear tests were performed on 16 dogs with hyperadrenocorticism, 18 with diabetes and 12 with hypothyroidism together with 100 control dogs. Corneal sensitivity was also measured in 12 of the 18 diabetic dogs with a Cochet Bonnet aesthesiometer and compared with age‐ and breed‐matched normal dogs.

Results:Schirmer tear test values in dogs with hypothyroidism, hyperadrenocorticism and diabetes were 12·3±3·2, 14·0±4·0 and 12·3±5·3 mm/minutes, respectively. Schirmer tear test values were significantly lower than that for the control group (19·6±4·2 mm/minutes) in all dogs with an endocrinopathy. Only in two hypothyroid dogs and three diabetics, this was manifested as profound keratoconjunctivitis sicca with Schirmer tear test value lower than 5 mm/minutes. Diabetic dogs had significantly reduced corneal sensitivity compared with a matched set of control dogs.

ClinicalSignificance:This study shows a significant reduction in tear production in animals with diabetes mellitus, hypothyroidism and hyperadrenocorticism. Further research is needed to elucidate the mechanisms by which this reduction in tear production occurs. Assessment of tear production should be undertaken in animals diagnosed with these endocrinopathies, as these animals may progress to clinical keratoconjunctivitis sicca.
Turbulent
Heat Transfer in Ribbed Coolant Passages of Different Aspect Ratios: Parametric
Effects
Authors: Saha Arun
K. , Acharya Sumanta
Published: April 2007

Turbulent flow and heat transfer in rotating ribbed ducts of different aspect ratios (AR) are studied numerically using an unsteady Reynolds averaged Navier–Stokes procedure. Results for three ARs (1:1, 1:4, and 4:1) and staggered ribs with constant pitch (P∕e=10) in the periodically developed region are presented and compared. To achieve periodic flow behavior in successive inter-rib modules calculations are performed in a computational domain that extends to two or three inter-rib modules. The computations are carried out for an extended parameter set with a Reynolds number range of 25,000–150,000, density ratio range of 0–0.5, and rotation number range of 0–0.50. Under rotational conditions, the highest heat transfer along the leading and side walls are obtained with the 4:1 AR, while the 1:4 AR has the highest trailing wall Nu ratio and the lowest leading wall Nu ratio. The 1:4 AR duct shows flow reversal near the leading wall (leading to low Nu) at high rotation numbers and density ratios. For certain critical parameter values (low Re, high Ro, and/or DR), the leading wall flow is expected to become nearly stagnant, due to the action of centrifugal buoyancy, leading to conduction-limited heat transfer. The 4:1 AR duct shows evidence of multiple rolls in the secondary flow that direct the core flow to both the leading and trailing surfaces which reduces the difference between the leading and trailing wall heat transfer relative to the other two AR ducts.
Simulation of Interfacial Phonon Transport in Si–Ge Heterostructures Using an Atomistic Green’s Function Method
Authors: Zhang W. , Fisher T. S. , Mingo N.
Published: April 2007

An atomistic Green’s function method is developed to simulate phonon transport across a strained germanium (or silicon) thin film between two semi-infinite silicon (or germanium) contacts. A plane-wave formulation is employed to handle the translational symmetry in directions parallel to the interfaces. The phonon transmission function and thermal conductance across the thin film are evaluated for various atomic configurations. The contributions from lattice straining and material heterogeneity are evaluated separately, and their relative magnitudes are characterized. The dependence of thermal conductance on film thickness is also calculated, verifying that the thermal conductance reaches an asymptotic value for very thick films. The thermal boundary resistance of a single Si∕Ge interface is computed and agrees well with analytical model predictions. Multiple-interface effects on thermal resistance are investigated, and the results indicate that the first few interfaces have the most significant effect on the overall thermal resistance.
Heat and Mass Transfer Evaluation in the Channels of an Automotive Catalytic Converter by Detailed Fluid-Dynamic and Chemical Simulation
Authors: Arrighetti Cinzio , Cordiner Stefano , Mulone Vincenzo
Published: April 2007

The role of numerical simulation to drive the catalytic converter development becomes more important as more efficient spark ignition engines after-treatment devices are required. The use of simplified approaches using rather simple correlations for heat and mass transfer in a channel has been widely used to obtain computational simplicity and sufficient accuracy. However, these approaches always require specific experimental tuning so reducing their predictive capabilities. The feasibility of a computational fluid dynamics three-dimensional (3D) model coupled to a surface chemistry solver is evaluated in this paper as a tool to increase model predictivity then allowing the detailed study of the performance of a catalytic converter under widely varying operating conditions. The model is based on FLUENT to solve the steady-state 3D transport of mass, momentum and energy for a gas mixture channel flow, and it is coupled to a powerful surface chemistry tool (CANTERA). Checked with respect to literature available experimental data, this approach has proved its predictive capabilities not requiring an ad hoc tuning of the parameter set. Heat and mass transfer characteristics of channels with different section shapes (sinusoidal, hexagonal, and squared) have then been analyzed. Results mainly indicate that a significant influence of operating temperature can be observed on Nusselt and Sherwood profiles and that traditional correlations, as well as the use of heat/mass transfer analogy, may give remarkable errors (up to 30% along one-third of the whole channel during light-off conditions) in the evaluation of the converter performance. The proposed approach represents an appropriate tool to generate local heat and mass transfer correlations for less accurate, but more comprehensive, 1D models, either directly during the calculation or off-line, to build a proper data base.
Numerical Studies on Channel Formation and Growth During Solidification: Effect of Process Parameters
Authors: Jain Jayesh , Kumar Arvind , Dutta Pradip
Published: April 2007

In the present work, solidification of a hyper-eutectic ammonium chloride solution in a bottom-cooled cavity (i.e. with stable thermal gradient) is numerically studied. A Rayleigh number based criterion is developed, which determines the conditions favorable for freckles formation. This criterion, when expressed in terms of physical properties and process parameters, yields the condition for plume formation as a function of concentration, liquid fraction, permeability, growth rate of a mushy layer, and thermophysical properties. Subsequently, numerical simulations are performed for cases with initial and boundary conditions favoring freckle formation. The effects of parameters, such as cooling rate and initial concentration, on the formation and growth of freckles are investigated. It was found that a high cooling rate produced larger and more defined channels which are retained for a longer durations. Similarly, a lower initial concentration of solute resulted in fewer but more pronounced channels. The number and size of channels are also found to be related to the mushy zone thickness. The trends predicted with regard to the variation of number of channels with time under different process conditions are in accordance with the experimental observations reported in the literature.
A New Low Reynolds Stress Transport Model for Heat Transfer and Fluid in Engineering Applications
Authors: Jia Rongguang , Sundén Bengt , Faghri Mohammad
Published: April 2007

A new Reynolds stress transport model (RSTM) aimed for engineering applications is proposed with consideration of near-wall turbulence. This model employs the Speziale, Sarkar, and Gatski (SSG) pressure strain term, the ω equation, and the shear stress transport (SST) model for the shear stresses at the near-wall region (say, y+<30). The models are selected based on the following merits: The SSG RSTM model performs well in the fully turbulent region and does not need the wall normal vectors; the ω equation can be integrated down to the wall without damping functions. The SST model is a proper two-equation model that performs well for flows with adverse pressure gradient, while most two-equation models can have a good prediction of the shear stresses. A function is selected for the blending of the RSTM and SST. Three cases are presented to show the performance of the present model: (i) fully developed channel flow with Reτ=395, (ii) backward-facing step with an expansion ratio of 1.2 and Re=5200 base on the step height, and (iii) circular impingement with the nozzle-to-wall distance H=4D and Re=20,000. It is believed that the new model has good applicability for complex flow fields.
An
Explicit Algebraic Model for Turbulent Heat Transfer in Wall-Bounded Flow With Streamline
Curvature
Authors: Younis B.
A. , Weigand B. , Spring S.
Published: April 2007

Fourier’s law, which forms the basis of most engineering prediction methods for the turbulent heat fluxes, is known to fail badly in capturing the effects of streamline curvature on the rate of heat transfer in turbulent shear flows. In this paper, an alternative model, which is both algebraic and explicit in the turbulent heat fluxes and which has been formulated from tensor-representation theory, is presented, and its applicability is extended by incorporating the effects of a wall on the turbulent heat transfer processes in its vicinity. The model’s equations for flows with curvature in the plane of the mean shear are derived and calculations are performed for a heated turbulent boundary layer, which develops over a flat plate before encountering a short region of high convex curvature. The results show that the new model accurately predicts the significant reduction in the wall heat transfer rates wrought by the stabilizing-curvature effects, in sharp contrast to the conventional model predictions, which are shown to seriously underestimate the same effects. Comparisons are also made with results from a complete heat-flux transport model, which involves the solution of differential transport equations for each component of the heat-flux tensor. Downstream of the bend, where the perturbed boundary layer recovers on a flat wall, the comparisons show that the algebraic model yields indistinguishable predictions from those obtained with the differential model in regions where the mean-strain field is in rapid evolution and the turbulence processes are far removed from local equilibrium.
Numerical and Experimental Investigation of Melting in the Presence of a Magnetic Field: Simulation of Low-Gravity Environment
Authors: Zhang H. , Charmchi M. , Veilleux D. , Faghri M.
Published: April 2007

In this paper, numerical and experimental studies are presented on melting behavior of a pure metal in the presence of a static magnetic field. When a transverse magnetic field is present and the working fluid is electrically conductive, the fluid motion in the magnetic field results in a force field (Lorentz forces) that will dampen the convective flows. Buoyancy driven flows are the focus of this study to simulate low-gravity conditions. Hartmann (Ha) number, a dimensionless parameter proportional to the strength of the magnetic field, dominates the convection flow suppression. The effects of the magnetic strength on melting rate and on the profile of the solid/melt interface are studied. The experiments are conducted with pure gallium as phase change material inside a rectangular test cell. The solid thickness at its side center position is measured by an ultrasound device and the solid/melt interface profile is captured via reflection florescent-light photography. Temperature measurements and volume expansion/contraction tracking are used to provide further details and to verify the numerical results. Magnetically induced low-gravity environments were extensively studied numerically, where the details of the flow field were obtained. The experimental and numerical results compare very well especially, at larger Hartmann numbers. The results showed that a magnetic filed could be used to simulate key melting characteristics found in actual low-gravity environments. However, under strong magnetic field, numerical simulations revealed a different three-dimensional flow structure in the melt region compared to the actual low-gravity flow fields where the flow circulations are smoothly curved.
Modeling of Thermoelectric Properties of Semi-Conductor Thin Films With Quantum and Scattering Effects
Authors: Bulusu A. , Walker D. G.
Published: April 2007

Several new reduced-scale structures have been proposed to improve thermoelectric properties of materials. In particular, superlattice thin films and wires should decrease the thermal conductivity, due to increased phonon boundary scattering, while increasing the local electron density of states for improved thermopower. The net effect should be increased ZT, the performance metric for thermoelectric structures. Modeling these structures is challenging because quantum effects often have to be combined with noncontinuum effects and because electronic and thermal systems are tightly coupled. The nonequilibrium Green’s function (NEGF) approach, which provides a platform to address both of these difficulties, is used to predict the thermoelectric properties of thin-film structures based on a limited number of fundamental parameters. The model includes quantum effects and electron-phonon scattering. Results indicate a 26–90 % decrease in channel current for the case of near-elastic, phase-breaking, electron-phonon scattering for single phonon energies ranging from 0.2 meV to 60 meV. In addition, the NEGF model is used to assess the effect of temperature on device characteristics of thin-film heterojunctions whose applications include thermoelectric cooling of electronic and optoelectronic systems. Results show the predicted Seebeck coefficient to be similar to measured trends. Although superlattices have been known to show reduced thermal conductivity, results show that the inclusion of scattering effects reduces the electrical conductivity leading to a significant reduction in the power factor (S2σ).
Increasing Adiabatic Film-Cooling Effectiveness by Using an Upstream Ramp
Authors: Na Sangkwon , Shih Tom I-P.
Published: April 2007

A new design concept is presented to increase the adiabatic effectiveness of film cooling from a row of film-cooling holes. Instead of shaping the geometry of each hole; placing tabs, struts, or vortex generators in each hole; or creating a trench about a row of holes, this study proposes a geometry modification upstream of the holes to modify the approaching boundary-layer flow and its interaction with the film-cooling jets. Computations, based on the ensemble-averaged Navier–Stokes equations closed by the realizable k‐ε turbulence model, were used to examine the usefulness of making the surface just upstream of a row of film-cooling holes into a ramp with a backward-facing step. The effects of the following parameters were investigated: angle of the ramp (8.5deg, 10deg, 14deg), distance between the backward-facing step and the row of film-cooling holes (0.5D,D), blowing ratio (0.36, 0.49, 0.56, 0.98), and “sharpness” of the ramp at the corners. Results obtained show that an upstream ramp with a backward-facing step can greatly increase surface adiabatic effectiveness. The laterally averaged adiabatic effectiveness with a ramp can be two or more times higher than without the ramp by increasing upstream and lateral spreading of the coolant.
Numerical Simulation of Transport in Optical Fiber Drawing with Core–Cladding Structure
Authors: Chen Chunming , Jaluria Yogesh
Published: April 2007

Optical fibers are typically drawn from silica preforms, which usually consist of two concentric cylinders called the core and the cladding, heated in a high-temperature furnace. For optical communication purposes, the core always has a higher refractive index than the cladding to obtain total internal reflection. In order to investigate the effect of this core–cladding structure on optical fiber drawing, a numerical model has been developed in this work. Axisymmetric flows of a double-layer glass and aiding purge gas in a concentric cylindrical furnace are considered. The thermal and momentum transport in both glass layers and gas are coupled at the interface boundaries. The neck-down profile is generated using an iterative numerical scheme. The zonal method is applied to model the radiation transfer in the glass preform. The gas is taken as nonparticipating. Coordinate transformations are used to convert the resulting complex domains into cylindrical regions. The stream function, vorticity, and energy equations for the core, the cladding, and the purge gas are solved by finite difference methods, using a false transient approach coupled with the alternating direction implicit method. A second-order differencing scheme is used for discretization. The numerical results are validated by comparing with results available in the literature. The effects of changes in the refractive index and absorption coefficient due to doping on fiber drawing are investigated. This problem has received very little attention in the literature, particularly with respect to modeling, and this paper presents an initial study of the underlying transport.
Numerical Prediction of Fluid Flow and Heat Transfer in the Target System of an Axisymmetric Accelerator-Driven Subcritical System
Authors: Prakash K. Arul , Biswas G. , Kumar B. V. Rathish
Published: April 2007

Thermal hydraulics related to the design of the spallation target module of an accelerator-driven subcritical system (ADSS) was investigated numerically using a streamline upwind Petrov-Galerkin (SUPG) finite element (FE) method. A large amount of heat is deposited on the window and in the target during the course of nuclear reaction between the proton beam and the molten lead-bismuth eutectic (LBE) target. Simulations were carried out to predict the characteristics of the flow and temperature fields in the target module with a funnel-shaped flow guide and spherical bottom of the container. The beam window was kept under various thermal conditions. The analysis was extended to the case of heat generation in the LBE. The principal purpose of the analysis was to trace the temperature distribution on the beam window and in the LBE. In the case of turbulent flows, the number of recirculation regions is decreased and the maximum heat transfer was found to take place downstream of the stagnation zone on the window.