bluuebunny/crossref_metadata_2025 huggingface dataset:
Does a telephone follow‐up intervention for patients discharged with acute myocardial infarction have long‐term effects on health‐related quality of life? A randomised controlled trial
Authors: Hanssen Tove Aminda , Nordrehaug Jan Erik , Eide Geir Egil , Hanestad Berit Rokne
Published: April 2009

Aims.  An earlier combined proactive and reactive telephone follow‐up intervention for acute myocardial infarction patients after discharge from hospital showed positive effects after six months. The aim of the present study was to assess whether the intervention has long‐term effects up to 18 months after discharge.

Design.  A prospective randomised controlled trial with 18 months follow‐up.

Method.  The trial was conducted with 288 patients allocated to a telephone follow‐up intervention group (n = 156) or control group (n = 132). The primary endpoint was health‐related quality of life using the SF‐36. Secondary endpoints included smoking and exercise habits, return to work and rehospitalisation due to chest pain.

Results.  There were significant improvements over time on most dimensions of health‐related quality of life in both the intervention and control group to US norm population levels on most SF‐36 dimensions and summary scores. The intervention group showed no overall significant improvement beyond six months in the physical or mental summary scores, but there was a significant effect for those aged 70 or above. Although there was a promising effect for rehospitalisation due to chest pain, no significant differences were found between the groups on the secondary endpoints after six months.

Conclusion.  This study demonstrated that despite positive short‐term effects at six months, the telephone follow‐up intervention had no long‐term effects on health‐related quality of life or secondary endpoints. However, the potential for improvement beyond six months was less than anticipated reflecting a reduced morbidity among acute myocardial infarction patients.

Relevance to clinical practice.  Telephone follow‐up after discharge from hospital is an easy implementable follow‐up intervention enabling individualised provision of information and support in a time often experienced as stressful by patients. Our study indicates that six months is an adequate support period. Despite positive results six months after discharge no significant added long‐term effects of telephone follow‐up, compared to usual care were found in this study.
The decision making of heart failure specialist nurses in clinical practice
Authors: Dowding Dawn , Spilsbury Karen , Thompson Carl , Brownlow Ros , Pattenden Jill
Published: April 2009

Aims and objectives.  To explore decision processes and types of decisions made by heart failure specialist nurses.

Background.  Heart failure specialist nurses are key to the management of patients with heart failure in the community. In previous studies heart failure specialist nurses have reported difficulty in developing decision making skills. Cognitive continuum theory can be used to examine the relationship between decision tasks and the processes used by heart failure specialist nurses to make decisions.

Design.  A qualitative study using non‐participant observation and semi‐structured interviews.

Methods.  Six heart failure specialist nurses were observed while they carried out consultations with three patients each (n = 18). Twelve heart failure specialist nurses were interviewed about their decision making in practice. Data were analysed using thematic content analysis.

Results.  Two areas of decision making were identified by heart failure specialist nurses as key; pharmacological management and managing patients in the palliative phase of their condition. Pharmacological management decisions involved the trading off of risks and benefits of titrating medication, with nurses using internalised guidelines to inform their practice. In contrast, nurses relied on support from other health care professionals when making decisions about a patient’s need for palliative care.

Conclusions.  Medication titration decisions have a mixture of intuition and analysis inducing features making them amenable to the use of decision tools. The timing of the need for palliative care is less predictable, suggesting an intuitive approach to decision making may be more appropriate.

Relevance to clinical practice.  There are several strategies that could be used to improve the match between the decisions that heart failure specialist nurses take and the decision processes they use. These include the development of more tailored decision support tools for medication titration decisions and the provision of structured decision aids for assessing patients’ need for palliative care.
Fatigue in multiple sclerosis patients
Authors: Mollaoğlu Mukadder , Üstün Emine
Published: April 2009

Aim.  This study aimed to describe fatigue and the factors that affect fatigue in people with multiple sclerosis.

Background.  Fatigue is the most common symptom and has the greatest effect on multiple sclerosis patients’ activities of daily living. There is limited understanding of the level of fatigue experienced by people with multiple sclerosis, with research currently limited to other symptoms and problems related to multiple sclerosis.

Design.  This research was conducted as a descriptive survey.

Methods.  The study involved 120 people with multiple sclerosis. The data were collected with a Patient Questionnaire and a Visual Analogue Scale for Fatigue (VAS‐F). Variance analysis, Mann–Whitney U‐test and Kruskal–Wallis test were used in the data analysis.

Results.  All of the individuals in the sample experienced fatigue. Their fatigue was also affected by factors such as age, gender, education, marital status, number of children, occupation and duration of illness. In addition, the situations with the greatest effect on their fatigue were taking a hot bath/shower, hot/humid weather, stress, infection and other illnesses causing fever, disturbance in sleep pattern, increase in daily activities and exercise.

Conclusions.  Fatigue is a symptom that has a significant effect on the daily lives of people with multiple sclerosis. Accordingly, it is recommended that factors affecting fatigue in people with multiple sclerosis be evaluated and that education programmes directed at how to control these factors.

Relevance to clinical practice.  The determination of factors affecting fatigue is important for multiple sclerosis individuals’ ability to cope with fatigue and keep it under control. To be able to accomplish this it is necessary for health care personnel, the family and friends to work together.
Molecules and beyond: assessing the distinctness of the Great Lakes wolf
Authors: SCHWARTZ MICHAEL K. , VUCETICH JOHN A.
Published: April 2009

The dog family, Canidae, is a widely distributed group of species that have evolved and radiated relatively recently into 16 genera and 36 recognized species (Nowak 1999). Specific taxonomic designations for some canid taxa can be unclear due to frequent interspecific hybridization among species in both historical and contemporary times, and our imperfect molecular genetic approaches for determining among a series of hypotheses regarding hybridization and evolution. In this issue of Molecular Ecology, Koblmüller et al. tackle the difficult topic of Great Lakes wolf taxonomy and present data that suggest this taxon is currently genetically distinct despite a long history of human persecution and hybridization with related taxa.
CsiA is a bacterial cell wall synthesis inhibitor contributing to DNA translocation through the cell envelope
Authors: Stentz Régis , Wegmann Udo , Parker Mary , Bongaerts Roy , Lesaint Laurie , Gasson Mike , Shearman Claire
Published: April 2009

Conjugation is a widely spread mechanism allowing bacteria to adapt and evolve by acquiring foreign DNA. The chromosome of Lactococcus lactis MG 1363 contains a 60 kb conjugative element called the sex factor capable of high‐frequency DNA transfer. Yet, little is known about the proteins involved in this process. Comparative genomics revealed a close relationship between the sex factor and elements found in Gram‐positive pathogenic cocci. Among the conserved gene products, CsiA is a large protein that contains a highly conserved domain (HCD) and a C‐terminal cysteine, histidine‐dependent amidohydrolases/peptidases (CHAP) domain in its C‐terminal moiety. Here, we show that CsiA is required for DNA transfer. Surprisingly, increased expression of CsiA affects cell viability and the cells become susceptible to lysis. Point mutagenesis of HCD reveals that this domain is responsible for the observed phenotypes. Growth studies and electron microscope observations suggest that CsiA is acting as a cell wall synthesis inhibitor. In vitro experiments reveal the capacity of CsiA to bind d‐Ala–d‐Ala analogues and to prevent the action of penicillin binding proteins. Our results strongly suggest that CsiA sequesters the peptidoglycan precursor and prevents the final stage of cell wall biosynthesis to enable the localized assembly of the DNA transfer machinery through the cell wall.
Impact of rRNA methylations on ribosome recycling and fidelity of initiation in Escherichia coli
Authors: Seshadri Anuradha , Dubey Badrinath , Weber Michael H. W. , Varshney Umesh
Published: April 2009

Ribosomal RNA (rRNA) contains a number of modified nucleosides in functionally important regions including the intersubunit bridge regions. As the activity of ribosome recycling factor (RRF) in separating the large and the small subunits of the ribosome involves disruption of intersubunit bridges, we investigated the impact of rRNA methylations on ribosome recycling. We show that deficiency of rRNA methylations, especially at positions 1518 and 1519 of 16S rRNA near the interface with the 50S subunit and in the vicinity of the IF3 binding site, adversely affects the efficiency of RRF‐mediated ribosome recycling. In addition, we show that a compromise in the RRF activity affords increased initiation with a mutant tRNAfMet wherein the three consecutive G‐C base pairs (29GGG31:39CCC41), a highly conserved feature of the initiator tRNAs, were mutated to those found in the elongator tRNAMet (29UCA31:39ψGA41). This observation has allowed us to uncover a new role of RRF as a factor that contributes to fidelity of initiator tRNA selection on the ribosome. We discuss these and earlier findings to propose that RRF plays a crucial role during all the steps of protein synthesis.
Parents of school students on childhood overweight: The Weight of Opinion Study
Authors: Booth Michael L , King Lesley A , Pagnini Deanna L , Wilkenfeld Rachel L , Booth Susan L
Published: April 2009

Aim: The perceptions of parents of school‐aged children regarding child and adolescent overweight and obesity were examined.

Method: Parents with children in primary and secondary schools in socio‐economically diverse areas across metropolitan Sydney and rural New South Wales, Australia, were recruited for focus group discussions. Content analysis was used to analyse the focus group transcripts.

Results: Participants were concerned about overweight among school‐aged children and young people, but were reluctant to address it with their own children. The parents wanted general practitioners to raise the issue, but not other professionals or friends/relations. The participants agreed that schools had an educational role to play in both healthy eating and physical activity, but disagreed about whether schools should regulate foods brought from home or supplied at school. Parents suggested various ways of restricting marketing to children, educating parents and children, increasing opportunities for physical activity and increasing access to healthier foods.

Conclusions: Parents are concerned about overweight among children and adolescents, but are reluctant to take action, and would find it difficult to be effective change agents. There are opportunities for intervention, but they must recognise the salient emotional issues associated with weight and food among parents.
The patterns of spontaneous Ca2+ signals generated by ventral spinal neurons in vitro show time‐dependent refinement
Authors: Sibilla Sara , Fabbro Alessandra , Grandolfo Micaela , D’Andrea Paola , Nistri Andrea , Ballerini Laura
Published: April 2009

Embryonic spinal neurons maintained in organotypic slice culture are known to mimic certain maturation‐dependent signalling changes. With such a model we investigated, in embryonic mouse spinal segments, the age‐dependent spatio‐temporal control of intracellular Ca2+ signalling generated by neuronal populations in ventral circuits and its relation with electrical activity. We used Ca2+ imaging to monitor areas located within the ventral spinal horn at 1 and 2 weeks of in vitro growth. Primitive patterns of spontaneous neuronal Ca2+ transients (detected at 1 week) were typically synchronous. Remarkably, such transients originated from widespread propagating waves that became organized into large‐scale rhythmic bursts. These activities were associated with the generation of synaptically mediated inward currents under whole‐cell patch‐clamp. Such patterns disappeared during longer culture of spinal segments: at 2 weeks in culture, only a subset of ventral neurons displayed spontaneous, asynchronous and repetitive Ca2+ oscillations dissociated from background synaptic activity. We observed that the emergence of oscillations was a restricted phenomenon arising together with the transformation of ventral network electrophysiological bursting into asynchronous synaptic discharges. This change was accompanied by the appearance of discrete calbindin immunoreactivity against an unchanged background of calretinin‐positive cells. It is attractive to assume that periodic oscillations of Ca2+ confer a summative ability to these cells to shape the plasticity of local circuits through different changes (phasic or tonic) in intracellular Ca2+.
Post‐training excitotoxic lesions of the dorsal hippocampus attenuate generalization in auditory delay fear conditioning
Authors: Quinn Jennifer J. , Wied Heather M. , Liu Dorothy , Fanselow Michael S.
Published: April 2009

An abundance of evidence indicates a role for the dorsal hippocampus (DH) in learning and memory. Pavlovian fear conditioning provides a useful model system in which to investigate DH function because conditioning to polymodal contextual cues, but generally not to discrete unimodal cues, depends upon the integrity of the DH. There is some suggestion that the hippocampus may be involved in generalization to discrete auditory stimuli following conditioning, but the available literature offers conflicting results regarding the nature of hippocampus involvement. The present experiments were designed to address a role for the DH in auditory generalization following delay fear conditioning. Rats were trained with two or 16 trials of delay fear conditioning and subsequently given a neurotoxic lesion of the DH or sham surgery. Upon recovery, they were tested for fear conditioned responding to the auditory stimulus they were trained with, as well as generalized responding to a novel auditory stimulus. Sham animals showed substantial generalization to the novel stimulus when trained with two or 16 trials. However, lesion animals showed much less generalization (better discriminative performance) to the novel stimulus following 16 conditioning trials while still showing substantial fear conditioned freezing to the trained stimulus. A second experiment showed that this effect was not the result of a non‐associative response to the novel stimulus. We conclude that, with extended training, animals become capable of discriminating between trained and novel stimuli but another hippocampus‐dependent process maintains generalized responding.
Immunological cost of chemical defence and the evolution of herbivore diet breadth
Authors: Smilanich Angela M. , Dyer Lee A. , Chambers Jeffrey Q. , Bowers M. Deane
Published: April 2009

Selective pressures from host plant chemistry and natural enemies may contribute independently to driving insect herbivores towards narrow diet breadths. We used the specialist caterpillar, Junonia coenia (Nymphalidae), which sequesters defensive compounds, iridoid glycosides, from its host plants to assess the effects of plant chemistry and sequestration on the larval immune response. A series of experiments using implanted glass beads to challenge immune function showed that larvae feeding on diets with high concentrations of iridoid glycosides are more likely to have their immune response compromised than those feeding on diets low in these compounds. These results indicate that larvae feeding on plants with high concentrations of toxins might be more poorly defended against parasitoids, while at the same time being better defended against predators, suggesting that predators and parasitoids can exert different selective pressures on the evolution of herbivore diet breadth.
When tolerance leads to intolerance: Accessibility effects on social judgment
Authors: ARAYA TADESSE , EKEHAMMAR BO
Published: April 2009

We investigated the effects of unobtrusively primed constructs that were evocative of tolerance (e.g., tolerant, nonprejudiced) on subsequent task performances and found, contrary to our expectation, contrast effects in the judgment of an ambiguous behavioral description (Study 1 and 2). Suspecting that these results might be the outcome of social‐comparison processes, in Study 3, we attempted to corroborate our findings by providing the participants with either an explicit or implicit comparison standard. The results showed that the participants who were provided with the implicit comparison standard evaluated the target behavior as more intolerant as compared to those with the explicit or no comparison standard. The results are discussed in relation to the moderating role of automatic social‐comparison processes in the incidence of assimilation and contrast effects and the reduction of prejudice.
The Behavior Problems Inventory: Reliability and Factor Validity in Institutionalized Adults with Intellectual Disabilities
Authors: González Melissa L. , Dixon Dennis R. , Rojahn Johannes , Esbensen Anna J. , Matson Johnny L. , Terlonge Cindy , Smith Kimberly R.
Published: April 2009

Background  The aim of this study was to reevaluate the reliability (internal consistency, inter‐rater and re‐test) and the factor structure of the Behavior Problems Inventory (BPI‐01) with adults with intellectual disabilities who resided in a state‐run developmental centre.

Methods  BPI‐01 was administered to informants who had known participants for a minimum of 6 months. For study 1, data were collected in two samples: 100 residents who were selected based on the challenging behaviour targeted in their behaviour treatment plan and 325 randomly selected residents.

Results  The internal consistencies of the BPI‐01 subscales were in the good to excellent range. Overall, the inter‐rater and test–re‐test reliability of the subscales and items were adequate with relatively lower reliability found for the Stereotypy subscale and items. For study 2, the data of the 425 participants from study 1 were used in a confirmatory factor analysis, which indicated that three a priori BPI‐01 subscales (Self‐Injurious Behavior, Stereotyped Behavior and Aggression/Destruction) were a reasonable fit.

Conclusions  The current study provides additional support to the reliability and factor structure of the BPI‐01 in adults with intellectual disabilities.
Transient high glycaemic intake in the last trimester of pregnancy increases offspring birthweight and postnatal growth rate in sheep: a randomised control trial
Authors: Smith NA , McAuliffe FM , Quinn K , Lonergan P , Evans ACO
Published: April 2009

Objective  Investigate the effect of transient hyperglycemic intake (analogous to snacking on high glycaemic foods) in the third trimester of pregnancy on offspring birthweight and subsequent growth in sheep.

Design  Randomised trial.

Setting  University research farm.

Sample  Third trimester pregnant ewes.

Methods  Ewes were blocked on weight, age and litter size and were randomly assigned to receive oral administration of 100 ml of propylene glycol (PG; n = 51) or 100 ml of water (control, C; n = 53) twice/day. Twice during treatment, 12 ewes from each group were selected and blood samples collected to determine the glucose and insulin response to treatment.

Main outcome measures  At birth, blood was collected from the lambs, their body dimensions measured and body weights recorded at 0, 6 and 12 weeks of age after which lambs were slaughtered when they reached 40 kg live weight.

Results  Administration of PG elevated (P < 0.05) plasma glucose and insulin concentrations for 2 hours post administration compared with control ewes. Lambs (C: n = 80; PG: n = 70) born to ewes fed high glycaemic meals had higher birthweights (C: 5.01 ± 0.18 kg; PG: 5.27 ± 0.22 kg, P = 0.032), plasma glucose concentrations (P = 0.001) and ponderal index (weight/height3, P = 0.043) and reached a similar (P > 0.05) slaughter carcass weight (C: 20.0 ± 0.51 kg; PG: 20.6 ± 0.55 kg) at an earlier age (PG: 166.0 ± 13.2; C: 183.4 ± 13.8 days, P = 0.039) compared with control lambs.

Conclusions  Transient high glycaemic intakes in the third trimester of pregnancy resulted in heavier offspring at birth that had faster growth rates in early postnatal life. This animal model is relevant for studying the relationship between maternal diet, fetal size and the risk of childhood obesity.
Use of agricultural by‐products to study the pH effects in an acid tea garden soil
Authors: Wang N. , Li J.‐Y. , Xu R.‐K.
Published: April 2009

The amelioration of an acid Alfisol from a tea garden was studied by incorporating various plant materials: canola straw, wheat straw, rice straw, corn straw, soybean straw, peanut straw, faba bean straw, Chinese milk vetch shoot and pea straw prior to incubation for a maximum of 65 days. Soil pH increased after incubation with all the incorporated materials with the legumes causing the largest increases. The final soil pH was correlated with ash alkalinity (r2 = 0.73), base cations (r2 = 0.74) and N content (r2 = 0.93) of the applied materials. It was assumed that the incubation released the base cations in plant materials as they decomposed which ultimately increased the base cation saturation of the soil. Similarly, soil exchangeable Al was also decreased with the incorporation of the legume plant materials and corn straw and rice straw. Our investigation demonstrated that legumes are the preferred choice for controlling the soil acidity and also for reducing the toxicity of Al in acid soils.
Diastolic Function Study with Conventional and Pulsed Tissue Doppler Echocardiography Imaging in Acromegalic Patients
Authors: Leães Carolina G. S. , Kramer Caroline K. , Pereira‐Lima Julia F. S. , Hatem Domingos M. , Castro Iran , Oliveira Miriam da C.
Published: April 2009

Acromegaly is associated with myocardial hypertrophy and it can progress to diastolic and systolic dysfunction. Purpose: To evaluate diastolic function in acromegalic patients through conventional echocardiography (CD) and tissue Doppler imaging (TDI). Methods: Seventeen acromegalic patients were submitted to CD and TDI, and early (E) and atriogenic (A) transmitral flow were evaluated in mitral, septal, and tricuspid regions. Results: In comparison with controls the means of conventional (1.06), septal (1.01), and tricuspid (0.98) E/A ratio were significantly lower in acromegalic patients. E/A ratio <1.0 was demonstrated in 41% and 49% of acromegalics by DC and TDI, respectively, with no statistical difference among the two methods. An inverse linear correlation was shown between mitral E/A ratio and acromegalic age (r =−0.7). Conclusion: In this study, DC and TDI were equally effective in demonstrating diastolic dysfunction, a common finding in acromegalic patients. (ECHOCARDIOGRAPHY, Volume 26, July 2009)
Explaining Incivility in the Workplace: The Effects of Personality and Culture
Authors: Liu Wu , Steve Chi Shu‐Cheng , Friedman Ray , Tsai Ming‐Hong
Published: April 2009

This study examines individual and cultural antecedents of incivility in the workplace, using a sample of MBAs and EMBAs from Taiwan and the United States. We predicted that individual achievement orientation would enhance incivility, based on Dollard’s frustration aggression hypothesis, and that those who were higher in direct conflict self‐efficacy (i.e., beliefs in one's skills in managing direct conflict) would be higher in incivility. These predictions were supported. We also predicted, and found, that collectivism orientation constrains these main effects, so that for those high in collectivism, the impact of achievement orientation and direct conflict self‐efficacy is weak or nonexistent. Implications for conflict management are discussed.
Empowering Individuals for Team Innovation in China: Conflict Management and Problem Solving
Authors: Tjosvold Dean , Yu Zi‐you , Wu Peiguan
Published: April 2009

Although emphases on teams and on individuals are often considered mutually exclusive, teams both rely upon individuals to perform their tasks skillfully and can support and encourage individuals to perform effectively. This study proposes that team capability to help individual team members overcome obstacles to performance facilitates the integration of individual’s ideas and efforts that results in team innovation. It further suggests that managing conflict cooperatively helps teams provide effective support so that individuals solve problems and contribute. Two hundred employees in 100 work teams in China completed measures of their team’s cooperative, competitive, and avoiding approaches to managing conflict and team support for problem solving by individuals, and 100 managers indicated the team’s innovation. Structural equation analysis suggests that a cooperative conflict management approach promotes group support for problem solving by individuals that in turn results in team innovation. These findings, coupled with previous research, suggest that cooperative conflict management and team assistance to help individuals solve problems provide a strong foundation for innovative teams.
Characterization of polymorphic microsatellite DNA markers in the black‐tailed godwit (Limosa limosa: Aves)
Authors: VERKUIL YVONNE I. , TRIMBOS KRIJN , HADDRATH OLIVER , BAKER ALLAN J. , PIERSMA THEUNIS
Published: April 2009

We isolated and tested 16 microsatellite loci in black‐tailed godwits from the Netherlands (Limosa limosa limosa), and from Australasia (subspecies melanuroides). One locus was monomorphic, two loci had null‐alleles and one was significantly heterozygote deficient. The remaining 12 polymorphic loci had on average 7.9 alleles (range 5–11) and the mean expected heterozygosity was 0.69. No significant linkage disequilibrium between the loci was observed and all loci were autosomal. Fourteen loci were successfully cross‐amplified in bar‐tailed godwit (Limosa lapponica).
Clinical features of type 1 autoimmune hepatitis in adolescence and early adulthood
Authors: Miyake Yasuhiro , Iwasaki Yoshiaki , Kobashi Haruhiko , Yasunaka Tetsuya , Ikeda Fusao , Takaki Akinobu , Okamoto Ryoichi , Takaguchi Kouichi , Ikeda Hiroshi , Makino Yasuhiro , Sakaguchi Kohsaku , Ando Masaharu , Yamamoto Kazuhide
Published: April 2009

Aim:  The peak age of the presentation of autoimmune hepatitis (AIH) is between 40 years and 50 years. Elderly patients have been reported to have higher frequencies of concurrent thyroid or rheumatic diseases and histological cirrhosis and a lower occurrence of treatment failure. In this study, we assessed the clinical features of Japanese type 1 AIH in adolescence and early adulthood.

Methods:  Fifteen patients aged ≤ 30 years (group 1) were compared with 79 patients aged between 40 years and 50 years (group 2).

Results:  At presentation, patients aged ≤ 30 years accounted for 9% of the study population. Although frequencies of extrahepatic concurrent autoimmune diseases were similar between groups 1 and 2, a tendency toward a lower frequency of concurrent autoimmune thyroiditis was shown in group 1 (0 vs. 18%, P = 0.08). Group 1 had a lower frequency of human leukocyte antigen DR4 (27 vs. 78%, P = 0.002), and histological acute hepatitis was shown more frequently in group 1 (27 vs. 4%, P = 0.002). However, there were no differences in frequencies of the normalization of serum transaminase levels after the introduction of corticosteroid treatment or relapse after the normalization of serum transaminase levels between the two groups.

Conclusions:  Japanese type 1 AIH patients in adolescence and early adulthood respond well to corticosteroid treatment. However, they may frequently show atypical features, and the diagnosis of type 1 AIH in adolescence and early adulthood may be difficult and should be made carefully.
In Situ Measurement of Water Temperature With a Sensor Using Interferometry
Authors: Tomita Eiji , Kawahara Nobuyuki , Toda Yasuji
Published: April 2009

It is very important to measure fluid temperature in research and industrial fields. However, there are no devices with high-response measurement. In this study, a sensor system is proposed to measure the temperature with very high response using interferometry. The sensor for temperature measurement utilizes the difference in measurement length between two laser beams. Both are the test beams, and there is no reference beam. The two beams pass mostly through closely arranged paths; therefore, the effect of mechanical vibration on the two test beams is expected to be very small. The laser beam was introduced through a selfoc micro lens (SML) into a polarization-maintaining fiber connected with a sensor part. The beam emitted from another SML was divided into two. Both beams enter a quartz block and are reflected at the corner to change direction by an angle of a quarter pai radian. They then pass through the test section although the lengths of the two beams are different in the measurement region. This sensor was installed on a side wall of a vessel. Water was poured into the vessel and stirred with a hot magnetic stirrer. The temperature near the sensor was also measured with a thermocouple as a reference. This paper focuses on the confirmation and evaluation of this system of temperature measurement. When the direction of the fringe shift with two photo-detectors was judged, the direction of the temperature could be distinguished. One feature of this sensor is that it minimizes the effect of the thermal boundary layer. If the condition of the fluid near the test section is uniform, both beams have almost the same boundary layers. Then, both thermal boundary layers are expected to be cancelled because the length of the test section is the difference between both beams. As a result, it was confirmed that this sensor system is useful for detecting changes in water temperature.
A Numerical Study of the Role of Interfacial Heat Transfer in Forced Convection Ice Melting Modeling
Authors: Ansari Naseem , Guetari Chokri , Martin Richard , Thompson Tim
Published: April 2009

In this paper, a numerical study of the role of interfacial heat transfer in the CFD modeling of forced convection ice melting is presented. Two different approaches are typically used in the simulation of ice melting phenomena. In the first approach, a single phase approximation is used, where ice and water phases are assumed to be in local thermodynamic equilibrium. A single temperature field is solved for the two components and phase change is assumed to occur very rapidly. In this approach, the heat transfer between ice and water is assumed infinite and ice and water mass fractions are determined from the ice-water phase diagram. In the second approach, a multiphase non-equilibrium approach is used where distinct velocity and temperature fields are solved for ice and water. The inherent assumption in the multiphase approach is that the rate of melting is not infinite and is controlled by the ice-water interface heat transfer coefficient. A correct estimation of the interfacial heat transfer coefficient is crucial in setting up a proper model for ice melting. A correlation for the interfacial heat transfer coefficient is derived numerically in this paper as a function of local turbulence intensity. It is shown that the equilibrium methodology is essentially a limiting form of the non-equilibrium approach and one could recover the equilibrium approach results by making the interfacial heat transfer coefficient large, i.e. infinite, in the multiphase simulation.
Critical Heat Flux Enhancement Through Improved Surface Wettability With Surface Oxides and Nanofluids
Authors: Coursey Johnathan S. , Kim Jungho
Published: April 2009

Surface wetting characteristics have been shown to affect the critical heat flux (CHF) observed during boiling. Surface oxidation is known to improve the ability of the fluid to wet the surface thus enhancing CHF. Nanofluids have also shown potential to enhance CHF, but the mechanisms are poorly understood. This study is targeted towards investigating whether or not nanofluids improve CHF by altering the surface energy. The surface energy of a heater was altered by oxidizing the surface to varying degrees or depositing metal onto the surface, and was characterized by measuring the advancing three-phase contact angle. Boiling curves were determined for water and ethanol based nanofluids with aluminum oxide nanoparticle concentrations from 0.001 g/l to 0.5 g/l as well as pure fluids on surfaces of varying surface energy. A 2.7 cm2 copper heater (polished or oxidized) was used for the water-based measurements. A 1.1 cm2 thick-film heater coated with glass and/or gold was used for the ethanol-based measurements. Boiling curves obtained using these fluid/surface combinations are discussed.
Topics of Heat Transfer Related to Single-Walled Carbon Nanotubes
Authors: Maruyama Shigeo
Published: April 2009

Using an alcohol catalytic CVD method shown to produce high-quality single-walled carbon nanotubes (SWNTs), films of vertically aligned (VA-)SWNTs were synthesized on quartz substrates. The VA-SWNTs can be removed from the substrate and transferred onto an arbitrary surface—without disturbing the vertical alignment—using a hot-water assisted technique. This ability makes experimental measurements of the anisotropic properties of SWNTs considerably less challenging. A series of molecular dynamics simulations have been performed to investigate a variety of heat conduction characteristics of SWNTs. Investigations of stationary heat conduction identifies diffusive-ballistic heat conduction regime in a wide range of nanotube-lengths. Furthermore, studies on non-stationary heat conduction show that the extensive ballistic phonon transport gives rise to wave-like non-Fourier heat conduction. Finally, several case studies are presented for SWNT heat transfer in more practical situations.
Modeling Heat Transfer Effects During Free-Form Fabrication: Multi-Dimensional Effects
Authors: Langerman Michael A.
Published: April 2009

Laser Powder Deposition (LPD) for additive fabrication is a relatively new technology that is currently being qualified for use in the manufacturing industry. Although this technology has significant advantages over conventional manufacturing processes, such as the reduced need for post-production part machining, the resulting component material properties (strength, ductility, etc.) are affected by process operating parameters such as laser power, head (manipulator) speed, and powder flow rate. Set points for these parameters are often based upon trial and error with process control requiring the oversight of a system operator. Additionally, thermal stresses that build up in the part and the substrate can lead to warping and separation of the part from the substrate. Although this latter effect has been investigated, no robust process control has been identified that will solve the problem. Therefore, to assure component part quality and to minimize residual stresses and attendant deformation, an intelligent laser deposition path planning control algorithm needs to be developed. Such control requires knowledge of the part thermal history. The process, however, is not amenable to direct experimental measurement, which has led to the need to develop accurate and reliable thermal models. Preliminary multi-dimensional results from one such model, discussed herein, show the need for process control and how such a model is central to developing an intelligent laser powder deposition path planning strategy.
Spine Fin Efficiency – A Three Sided Pyramidal Fin of Isosceles Triangular Cross-Sectional Area
Authors: Carranza Richard G.
Published: April 2009

An analytical, closed form, solution is presented for determining the fin efficiency of a spine fin with the geometry of a three sided pyramid with isosceles triangular cross-sectional area (from here on referred to as TSPICA). The solution is presented purely in terms of Bessel functions. The TSPICA is modeled using fundamental formulas of geometry. The governing equation is derived from a heat balance around the fin.
Molecular Dynamics Prediction of the Thermal Conductivity of Si/Ge Superlattices
Authors: Landry E. S. , McGaughey A. J. H. , Hussein M. I.
Published: April 2009

Molecular dynamics simulations and the non-equilibrium direct method are used to predict the thermal conductivity of a Si/Ge superlattice modeled by the Stillinger-Weber potential at a temperature of 300 K. We focus on the methodology of making the thermal conductivity prediction (limited effort has been made to model Si/Ge nanocomposites in the literature) and find that proper selection of the size and composition of the thermal reservoirs is important.
Generalized Two-Phase Pressure Drop and Heat Transfer Correlations in Evaporative Micro/Mini-Channels
Authors: Lee Hee Joon , Liu Dongyao , Yao Shi-Chune , Alyousef Y.
Published: April 2009

Existing data base and correlations in literature on the micro-channel pressure drop and heat transfer are reviewed. None of the existing correlations can cover the wide range of working fluids, operational conditions and different microchannel dimensions. The importance of the Bond number, which relates the nominal bubble dimension or capillary parameter with the channel size, is revealed. Using the Bond number, improved correlations of pressure drop and heat transfer are established. The new correlations predict the existing data well over wide ranges of working fluids, operational conditions and dimensions of micro-channels. Furthermore, Bond number could be used as a criterion to classify a flow path as a micro-channel or conventional macro-channel.
Experimental Measurement of Multiple Thermal Properties by Error Minimization
Authors: Smith Brian , Amon Cristina
Published: April 2009

Common thin film thermometry techniques are usually based on transient heat diffusion within a sample and its surroundings and are therefore sensitive to the film’s thermal conductivity (k) and heat capacity (C). This presents a problem of under-constraint in the numerical fitting models when both k and C of a given film are unknown. A number of approaches and assumptions have been studied to eliminate this dual dependence or estimate C analytically. However, they often amount to little more than fitting parameters, experimental assumptions, and rough estimates for many composite and polymer films that are emerging in the microelectronics and MEMS industries. The effect that the uncertainty in one property has on the prediction of the other is discussed in the framework of the polymer film PVDF used in many microsensor and actuator applications. An error surface analysis is used to describe the link between assumption and prediction for thermoreflectance and temperature phase measurement techniques. A methodology is presented that combines the results of two thermal tests through an error minimization algorithm to solve for both k and C with no analytical assumptions or approximations. This approach is demonstrated with an experimental test case, validated with synthesized data, and generalized to any system variable and a multitude of thin film thermometry variable or thin film thermometry technique.
Models for Gaseous Slip Flow in Non-Circular Microchannels
Authors: Duan Zhipeng , Muzychka Y. S.
Published: April 2009

Micro-scale fluid dynamics has received intensive interest due to the emergence of Micro-Electro-Mechanical Systems (MEMS) technology. Non-circular cross sections are common channel shapes that can be produced through a variety of micro-fabrication techniques. Non-circular microchannels have extensive practical applications in MEMS. Slip flow in noncircular microchannels has been examined by the authors and a review of several new models obtained by the authors is presented. These models are general and robust, and can be used by the research community for practical engineering design of microchannel flow systems. The reviewed models address: (i) fully developed slip flow in non-circular microchannels, (ii) hydrodynamically developing slip flow in non-circular microchannels, (iii) compressibility effects, and (iv) roughness effects. A model is proposed to predict the friction factor and Reynolds product fRe for fully developed and developing slip flow in most non-circular micro-channels. Compressibility effects on slip flow in non-circular microchannels have been examined and simple models are proposed to predict the pressure distribution and mass flow rate for slip flow in most non-circular microchannels. Finally, the effect of corrugated surface roughness on fully developed laminar flow in microtubes is examined. Simple analytical models are developed to predict friction factor and pressure drop in corrugated rough microtubes for continuum flow and slip flow.
Electron-Phonon Interaction Model and Thermal Transport Simulation During ESD Event in NMOS Transistor
Authors: Jin Jae Sik , Lee Joon Sik
Published: April 2009

An electron-phonon interaction model is proposed and applied to the transient thermal transport simulation during electrostatic discharge (ESD) event in the NMOS transistor. The high electron energy induced by the ESD in the transistor is transferred to the lattice phonons through electron-phonon interaction in the local region of the transistor. Due to this fact, a hot spot turns up, the size of which is much smaller than the phonon mean free path in the silicon layer. The full phonon dispersion model based on the Boltzmann transport equation (BTE) with the relaxation time approximation is applied to describe the interactions among different phonon branches and different phonon frequencies. The Joule heating by the electronphonon scattering is modeled through the intervalley and intravalley processes by introducing the average electron energy. In the simulation, the electron-phonon interaction model is used in the hot spot region, and then after a quasi-equilibrium state is achieved there, the temperature of lattice phonons in the silicon is calculated by using the phonon-phonon interaction model. The revolution of peak temperature in the hot spot during the ESD event is simulated and compared to that obtained by the previous full phonon dispersion model which treats the electron-phonon scattering as a volumetric heat source. The results show that the lower group velocity phonon modes (i.e. higher frequency) and optical mode of negligible group velocity obtain the highest energy density from electrons during the ESD event, which induces the devices melting phenomenon. The thermal response of phonon is also investigated, and it is found that the ratio of the phonon group velocity to the phonon specific heat can account for the phonon thermal response. If the ratio is higher than 2, the phonon have a good response to the heat input changes.
Optimization of Labyrinth Seal for Screw Compressor
Authors: Selvaraji M. , Joseph Sam P. , Nirmal N.
Published: April 2009

There is a growing demand for compressed air in the industry for various applications. Majority of industrial requirements is in line with screw compressor operating range. Design and construction of screw compressors are demanding tasks that require advanced calculations and theoretical knowledge. Clearances play a major role in the performance and reliability aspects of a screw compressor. Seals are provided in compressors to fit around rotor shafts in order to prevent the leakage of lubricating oil and working medium. However there is a small clearance between the seal and rotor shaft, which can cause potential leakage of the working medium. The performance of the compressor is directly related to the leakage rate through the seals. The labyrinth seal is a special type of seal, used in screw compressors and turbo-machinery for sealing purpose. Labyrinth seal is a non-contacting type seal that uses a tortuous path to minimize the gas leakage. The pressure drop occurs at each labyrinth tooth as the medium is squeezed between the labyrinth tooth and the rotor. The leakage through the seal is directly related to the labyrinth profile and also the clearance between the rotor and the labyrinth tooth. The present work is carried out to reduce the leakage through the labyrinth seal by optimising the tooth profile and operating clearances. Heat transfer analysis is carried out on the housing of the labyrinth seal to find out the boundary temperature of the seal. Also the heat transfer analysis on the labyrinth seal followed by Thermo-structural analysis is carried out to find out the accurate operating clearance of the seal. By using CFD as a tool, the optimisation is carried out on different design configurations of labyrinth seal by comparing the deviation in leakage rates. Effect of rotor speed, width of seal and pressure ratio on air leakage rate is also investigated. A set of labyrinth seals has been designed based on the above optimisation and tested in the compressor. The results have been compared with the CFD prediction.
Non-Intrusive Temperature Measurements Beneath Water Surface During Natural Convection
Authors: Bukhari Syed J. K. , Siddiqui Kamran
Published: April 2009

The waterside temperature field in a plane perpendicular to the air-water interface plays a dominant role during natural convection process. In the present study non-intrusive laser induced fluorescence technique has been used to investigate the temperature field of turbulent thermal convection in horizontal water layers during natural convection. Spatial distribution of the temperature field in a plane perpendicular to the surface shows the presence of the dark and bright regions that correspond to the falling cold and rising warm water, respectively. The horizontally averaged temperature profiles show a characteristic boundary layer distribution in the near surface region.
Prediction of the Saturation Pressure of Water From Non-Equilibrium Measurements
Authors: Duan Fei , Ward C. A.
Published: April 2009

Statistical rate theory (SRT) was applied to predict the saturation pressure of H2O based on the measurements of interfacial liquid-phase temperature, interfacial vapor-phase temperature, vapor-phase pressure, and average evaporation flux in non-equilibrium evaporation experiments. It is found that the predicted saturation pressure agrees with the Smithsonian Tables and Table given in the Handbook of Chemistry and Physics for water, H2O. SRT provides a new efficient method to determine the saturation-vapor pressure from a non-equilibrium precess.
Optimal Design of Coldplates for CPU Coolers
Authors: Rasmussen C. N. , Terp C. B.
Published: April 2009

We here present the results of an effort to determine the influence of the parameters affecting cold-plate performance and to minimize the total thermal resistance of a CPU cold-plate. An analysis based on analytical calculations and CFD simulations shows that spreading resistance is affected not only by the heat source area, cold-plate thickness and thermal conductivity of the cold-plate material, but also by the effective heat transfer coefficient of the interface between cold-plate and cooling liquid. Different options for optimizing heat transfer through the cold-plate are discussed.