bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the Thoracodorsal Artery: Morphology and Reactivity
Authors: BILLAUD MARIE , LOHMAN ALEXANDER W , STRAUB ADAM C , PARPAITE THIBAUD , JOHNSTONE SCOTT R , ISAKSON BRANT E
Published: February 2012

Please cite this paper as: Billaud M, Lohman AW, Straub AC, Parpaite T, Johnstone SR, Isakson BE. Characterization of the thoracodorsal artery: morphology and reactivity. Microcirculation 19: 360–372, 2012.

Objectives:  In this paper, we describe the histological and contractile properties of the thoracodorsal artery (TDA), which indirectly feeds the spinotrapezius muscle.

Methods:  We used immunolabelling techniques to histologically characterize the TDA while the contractile properties were assessed using pressure arteriography.

Results:  Our results demonstrate that the TDA is composed of approximately one to two layers of smooth muscle cells, is highly innervated with adrenergic nerves, and develops spontaneous tone at intraluminal pressures above 80 mmHg. The reactivity of the TDA in response to various contractile agonists such as phenylephrine, noradrenaline, angiotensin II, serotonin, endothelin 1, and ATP, as well as vasodilators, shows that the TDA exhibits a remarkably comparable reactivity to what has been observed in mesenteric arteries. We further studied the different components of the TDA response to acetylcholine, and found that the TDA was sensitive to TRAM 34, a blocker of the intermediate conductance potassium channel, which is highly suggestive of an endothelium‐dependent hyperpolarization.

Conclusions:  We conclude that the TDA exhibits comparable characteristics to other current vascular models, with the additional advantage of being easily manipulated for molecular and ex vivo vasoreactivity studies.
Reliability of Paper Brightness in Authenticating Documents
Authors: Green James A.
Published: February 2012

Abstract:  Evaluation of paper brightness in multipage documents is a practice of forensic document examiners when there is a question of a page insertion or substitution. This article demonstrates that occasional errors occur in the manufacturing process that affects the consistency of paper brightness. The inconsistency of paper brightness may therefore influence conclusions reached in authenticating documents. Reams of multipurpose paper, from 21 manufacturers, were examined. When assessing the individual pages of each package with an ultraviolet light, approximately 30% of the reams revealed differences in paper brightness. A study of the paper‐manufacturing process was conducted to determine where variations originate. It is concluded that brightness differences occur when one incompatible roll of paper is mistakenly placed with others used for one production run. It was also determined that brightness variations (when present) are patterned throughout individual reams. When the authenticity of a document is in question, consideration of these findings is essential to assure an accurate assessment.
Spontaneously formed nanostructures on titanium surfaces
Authors: Wennerberg Ann , Svanborg Lory Melin , Berner Simon , Andersson Martin
Published: February 2012

Objectives

The aim was to investigate the evolution of nanostructures on the SLActive surface, as a function of time, storage conditions, material dependence and to identify the step in which the reorganization of the outermost titanium oxide layer into well defined nanostructures takes place.

Material and methods

Titanium grade 2 discs were surface modified in seven different modes; (1) SLA (sand blasted, large grit, acid etched) protocol. (2) SLActive protocol (SLA stored in 0.9% NaCl solution), (3) SLActive, but stored in water instead of 0.9% NaCl solution, (4) pmod SLA: SLA discs subjected to oxygen plasma cleaning and stored in 0.9% NaCl solution, (5) SLAnano: SLActive discs aged for several months and then dried, (6) Mod A: same etching procedure and storage as for SLActive, but no sand blasting prior to etching, (7) pmod P: the discs were polished, oxygen plasma cleaned and stored in 0.9% NaCl solution. In addition TiZr alloy discs were prepared like the Ti SLActive samples. The surfaces were evaluated with SEM, interferometry, contact angle measurements and XPS.

Results

The samples stored dry were hydrophobic whereas the discs stored in liquid were hydrophilic. The evolution of nanostructures took 2 weeks, thereafter they were stable over time. The nanostructures occured after storage both in water and NaCl solution. Nanostructures were formed on Ti and TiZr although the morphology and distribution was quite different between the two materials.

Conclusions

Acid etching in conjunction with storage in aqueous solution is responsible for the reorganization of the outermost titanium oxide layer into well defined nanostructures.
Hematological: Low all‐cause mortality and low occurrence of antimicrobial resistance in hematological patients with bacteremia receiving no antibacterial prophylaxis: a single‐center study
Authors: Kjellander Christian , Björkholm Magnus , Cherif Honar , Kalin Mats , Giske Christian G.
Published: February 2012

Background:  Bacteremia is a major cause of morbidity and mortality in patients with hematological malignancies.

Objectives:  The aim of this study was to define temporal trends in species distribution, antimicrobial susceptibility, and all‐cause mortality in bacteremic hospitalized patients receiving no antibacterial prophylaxis during chemotherapy‐induced neutropenia.

Methods:  A total of 677 clinical episodes of bacteremia were identified in 463 patients during 2002–2008, and the results were compared with those published from the same institution during 1980–86 and 1988–2001. No major changes in patient selection were introduced during this period.

Results:  Between 2002 and 2008, the dominating pathogens were Escherichia coli (18%), coagulase‐negative staphylococci (15%), viridans streptococci (14%), Klebsiella spp. (10%), and Enterococcus faecium (8%). The 7‐d crude mortality rate was 5.2%. Polymicrobial bacteremia was seen in 25.7% of the patients who died within 7 d and in 13.1% of the survivors (P = 0.04). Acquired resistance was rarely observed, but a statistically significant increase in ciprofloxacin resistance in E. coli was observed. Comparing 2002–2008 with historical data from the same institution, the proportion of Gram‐positive isolates remained stable at 53–55% from 1988.

Conclusions:  The avoidance of fluoroquinolone prophylaxis may have contributed to a stable proportion of Gram‐positive bacteremia. The crude mortality was low in an international perspective. Acquired resistance was uncommon, but ciprofloxacin resistance in E. coli increased significantly. We believe that an indiscriminate use of antibacterial prophylaxis could be avoided in neutropenic patients without a negative impact on mortality.
Vegetation discontinuities and altitudinal indicator species in mountains ofWestGreenland: finding the best positions and traits to observe the impact of climate warming in theArctic
Authors: Jedrzejek Birgit , Drees Birgit , Daniëls Fred J. A. , Hölzel Norbert
Published: February 2012

Aims

To delineate boundaries of vegetation belts, characterize these belts by indicator species, plant functional types and plant distribution types, and explore options for climate change monitoring.

Location

Three research sites in the continental inland of West Greenland.

Methods

Based on spatially constrained clustering of 147 vegetation relevés and 145 transect plots of plant communities, boundaries of altitudinal vegetation belts were assessed. Indicators for altitudinal sections were identified from 664 vegetation relevés among vascular plants, bryophytes, lichens and plant functional types usingindicator species analysis. The performance of different plant groups along the altitudinal gradient was visualized with response curves.

Results

Boundaries of altitudinal vegetation belts were detected at 400, 800 and 1175 m a.s.l. on north‐facing slopes and at 450, 900 and 1250 m a.s.l. on south‐facing slopes. The resulting four vegetation belts were well defined by 99 indicator species and nine indicator plant functional types. Species, plant functional types and vascular plant distribution types showed clear sequences along the altitudinal gradient, which partly resemble their distribution along the latitudinal gradient.

Conclusions

As an easily observable expansion of shrubs and a decline of mosses and lichens is expected, the boundary at 400/450 m a.s.l. is particularly promising for climate change monitoring. The anticipated replacement of numerous cryophilous by thermophilous indicator species, as well as an obvious shift of plant functional types suggest several monitoring options at 800/900 m a.s.l. The summit areas above 1175/1250 m a.s.l., having a discontinuous plant cover, are considered to be especially vulnerable to fast invasion by species of lower altitudes such as woody plants and sedges. Due to steep gradients and short migration distances in mountains, it can be assumed that these anticipated changes in the study area will be stronger and faster than the already observed changes along the latitudinal gradient in lowland areas of the Arctic.
Inpatient Stroke Rehabilitation in Ontario: Are Dedicated Units Better?
Authors: Foley Norine , Meyer Matthew , Salter Katherine , Bayley Mark , Hall Ruth , Liu Ying , Willems Deborah , McClure J. Andrew , Teasell Robert
Published: February 2012

Background

The superiority of dedicated stroke rehabilitation over generalized rehabilitation services has been suggested by the literature; however, these models of service delivery have not been evaluated in terms of their relative effectiveness in situ.

Aims

A comparison of the process indicators associated with these two models of service provision was undertaken within the Ontario healthcare system.

Methods

All adults admitted with a diagnosis of stroke for inpatient rehabilitation in Ontario, Canada during the years 2006–2008 were identified from the National Rehabilitation Reporting System database. Each of the admitting institutions was classified as providing rehabilitation services on either a stroke dedicated or nondedicated unit. A dedicated unit was identified by the presence of a collection of geographically distinct, stroke-dedicated beds and dedicated therapists. Selected process indicators from the National Rehabilitation Reporting System database were compared between the two facility types.

Results

Sixty-seven facilities provided stroke rehabilitation services to 6709 adult stroke patients during the years 2006–2008. Of the total number of patients who entered inpatient rehabilitation, 1725 (25.7%) received care in eight facilities that met basic criteria for a dedicated stroke rehabilitation unit. On average, these patients took significantly longer to arrive for inpatient rehabilitation (37.2 ± 155.5 vs. 22.8 ± 95.0 days, P < 0.001), were admitted with higher Functional Independence Measure scores (77.5 ± 22.5 vs. 74.8 ± 24.5, P < 0.001), had significantly longer lengths of stay (42.1 ± 25.9 vs. 35.4 ± 27.2 days, P < 0.001), and demonstrated significantly lower Functional Independence Measure efficiency scores (0.62 ± 0.47 vs. 0.88 ± 1.03, P > 0.001) compared with patients who were admitted to nondedicated units. The proportion of patients admitted to a dedicated unit and subsequently discharged home was similar to that of patients discharged from nondedicated units (70.5% vs. 68.8%, P = 0.206).

Conclusions

In Ontario, patients admitted to dedicated stroke rehabilitation units fared no better on commonly-used process metrics compared with patients admitted to nondedicated rehabilitation units.
Intracranial Vessel Localization with Power Motion Doppler (PMD-TCD) Compared with CT Angiography in Patients with Acute Ischaemic Stroke
Authors: Barlinn Kristian , Zivanovic Zeljko , Zhao Limin , Kesani Maruthi , Balucani Clotilde , Tsivgoulis Georgios , Alexandrov Andrei V.
Published: February 2012

Introduction

With a view to develop an operator-independent monitoring system for sonothrombolysis, we aimed to evaluate the per cent agreement of power motion transcranial Doppler vessel tracks compared with computed tomography angiography in identification of the anterior and posterior circulation vessels in patients with acute ischaemic stroke.

Methods

Consecutive acute ischaemic stroke patients who underwent emergent brain computed tomography angiography and bedside power motion transcranial Doppler were studied. Depth ranges for detecting anterior and posterior circulation vessels were derived from power motion transcranial Doppler flow tracks and computed tomography angiography images of the circle of Willis. We calculated percent agreement of power motion transcranial Doppler with computed tomography angiography for the anterior and posterior circulation vessel localization using computed tomography angiography as reference.

Results

Samples were obtained from 34 acute ischaemic stroke patients (mean age 61 ± 16 years, 62% men, median National Institutes of Health Stroke Scale (NIHSS) score 5, interquartile range 2–8). A total of 229 Power motion Doppler computed tomography angiography vessel pairs were analysed. Power motion transcranial Doppler tracks for M1 and proximal M2 middle cerebral artery (MCA) were located at 24–68 mm (M1 MCA: 36–68 mm; M2 MCA: 24–53 mm); anterior cerebral artery (ACA): 50–78 mm; P1 posterior cerebral artery (PCA): 50–74 mm; left vertebral artery: 30–74 mm; right vertebral artery: 30–78 mm; basilar artery: 76–106 mm. The per cent agreement of power motion Doppler-transcranial Doppler for identifying proximal intracranial arteries compared to computed tomography angiography was: M1 and M2 MCA: 100% (95% confidence interval: 96–100%); M1 MCA: 98% (95% confidence interval: 86–100%); M2 MCA: 94% (95% confidence interval: 79–99%); A1 ACA: 82% (95% confidence interval: 68–91%); P1 PCA: 70% (95% confidence interval: 53–83%); left vertebral artery: 96% (95% confidence interval: 80–100%); right vertebral artery: 96% (95% confidence interval: 79–100%); basilar artery: 100% (95% confidence interval: 89–100%).

Conclusions

Power motion transcranial Doppler intercepts proximal vessels with good-to-excellent agreement with computed tomography angiography. Depth ranges (as opposed to average depths) can be used to target intracranial arterial segments for sonothrombolysis.
Exceptionally high mortality rate of the 1918 influenza pandemic in the Brazilian naval fleet
Authors: Schuck‐Paim Cynthia , Shanks G. Dennis , Almeida Francisco E. A. , Alonso Wladimir J.
Published: February 2012

Please cite this paper as: Schuck‐Paim et al. (2012) Exceptionally high mortality rate of the 1918 influenza pandemic in the Brazilian naval fleet. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2012.00341.x.

Background  The naval experience with the 1918 pandemic during World War I remains underexplored despite its key role on the pandemic’s global diffusion and the epidemiological interest of isolated and relatively homogeneous populations. The pandemic outbreak in the Brazilian naval fleet is of particular interest both because of its severity and the fact that it was the only Latin American military force deployed to war.

Objectives  To study the mortality patterns of the pandemic in the Brazilian fleet sent to patrol the West African coast in 1918.

Method  We investigated mortality across vessels, ranks, and occupations based on official population and mortality records from the Brazilian Navy Archives.

Results  The outbreak that swept this fleet included the highest influenza mortality rate on any naval ship reported to date. Nearly 10% of the crews died, with death rates reaching 13–14% on two destroyers. While overall mortality was lower for officers, stokers and engineer officers were significantly more likely to die from the pandemic, possibly due to the pulmonary damage from constant exposure to the smoke and coal dust from the boilers.

Conclusions  The fatality patterns observed provide valuable data on the conditions that can exacerbate the impact of a pandemic. While the putative lack of exposure to a first pandemic wave may have played a role in the excessive mortality observed in this fleet, our results indicate that strenuous labor conditions, dehydration, and exposure to coal dust were major risk factors. The unequal death rates among vessels remain an open question.
Molecular study and genotype/phenotype correlation of β thalassemia in Malaysia
Authors: SIVALINGAM M. , LOOI M. L. , ZAKARIA S. Z. S. , HAMIDAH N. H. , ALIAS H. , LATIFF Z. A. , IBRAHIM H. , JAMAL R.
Published: February 2012

Introduction:  To study the ß‐gene mutations spectrum, the genotype/phenotype correlation, the modulatory effect of co‐inherited factors such as α‐gene mutations and of Xmn1 polymorphism in a large cohort of Malaysian patients.

Methods:  A total of 264 cases clinically diagnosed as Thalassemia major (TM) (111), Thalassemia intermedia (21), HbE‐β Thalassemia (131), and 1 HbE homozygous were studied. The detection of α and ß gene mutations and characterization of Xmn1 polymorphism were performed by multiplex PCR, amplification refractory mutation system (ARMS), DNA sequencing, and restriction fragment length polymorphism (RFLP)‐PCR.

Results:  A total of 19 ß Thalassemia mutations were characterized. CD26 and CD41/42 were the most common found in the Malay and Chinese population, respectively. The sensitivity of the clinical diagnosis for β TM, thalassemia intermedia, and HbE/β thalassemia was 94.0%, 15.2%, and 89.2%, respectively. Patients with Xmn1 heterozygosity [+/−] required less frequent transfusion compared with those without the polymorphism. Co‐inheritance of α‐thalassemia alleviates the severity of HbE‐β thalassemia in our cohort.

Conclusion:  Molecular analysis should be used for a better diagnosis and management of β thalassemia.
Modelling the hydraulic impact of reintroducing large woody debris into watercourses
Authors: Thomas H. , Nisbet T.
Published: February 2012

Very little large woody debris (LWD) is present in UK river systems due to its removal from watercourses mainly for flood defence and angling purposes. Some researchers now believe that restoring LWD dams in rivers can aid in flood retention, improve habitat and biodiversity, and help improve water quality and reduce sediment transport. This study was carried out to model the potential impact of restoring five LWD dams into a small Welsh tributary within an existing area of flood plain woodland on flood flows. The model results suggest that the dams could increase water levels sufficiently during the design 1‐in‐100 year flow to reconnect the channel with its flood plain. The model predicts as much as a 2.1 m/s reduction in flow velocities behind the dams. Both factors contribute to the delaying of the flood peak by up to 15 min over a 0.5‐km reach. The results support the use of LWD dams as a viable soft engineering technique for complementing existing flood defences and aiding in downstream flood mitigation, although to be effective at a larger scale would require an extensive series of dams across the upper and middle reaches of a catchment.
Analysis of diabetic vitreopathy with dynamic light scattering spectroscopy – problems and solutions related to photon correlation
Authors: Fankhauser II Franz
Published: February 2012

Purpose:  To explore the molecular alterations of the vitreous by dynamic light scattering (DLS) spectroscopy (quasi‐elastic light scattering spectroscopy, photon‐correlation spectroscopy) in normals and in patients afflicted with various degrees of non‐proliferative and with proliferative diabetic retinopathy.

Methods:  Dynamic light scattering spectroscopy was employed to analyze the vitreous of normals and of patients with diabetes non‐invasively to estimate both the sizes and diffusion coefficients of mobile macromolecules and/or microparticles.

Results:  Abnormal molecular behaviour of vitreous molecules was observed in patients with diabetes afflicted with various degrees of diabetic vitreo‐retinopathy. In the non‐proliferative (background) retinopathy, both the diameters of the microparticles increase and the diffusion constants decrease significantly and progressively as the diabetic disease progresses. In the proliferative phase, a significant trend in the direction of smaller particles and greater diffusion constants is evident. These behaviours could also be interpreted as an increase in the viscosity of the intermolecular substance in the first case and as a decrease in the second.

Conclusions:  The vitreous in normals and even more so in diabetics with diabetic vitreo‐retinopathy is optically a highly non‐isotropic, multidispersive structure, making an optical analysis difficult. Advanced, but available models and technology, however, permits a major step forward in the optical analysis of the normal and the diseased vitreous.
Scleral buckling versus primary vitrectomy in rhegmatogenous retinal detachment study (SPR study): Risk assessment of anatomical outcome. SPR study report no. 7
Authors: Feltgen Nicolas , Heimann Heinrich , Hoerauf Hans , Walter Peter , Hilgers Ralf‐Dieter , Heussen Nicole ,   On behalf of Writing group for the SPR study investigators*
Published: February 2012

Purpose:  The ‘Scleral buckling versus primary vitrectomy in rhegmatogenous retinal detachment study’ (SPR study) is a randomized multicentre trial comparing primary vitrectomy (PV) and scleral buckling surgery (SB) for rhegmatogenous retinal detachment (RRD). This subanalysis was conducted to identify risk factors associated with anatomical outcomes.

Methods:  Relating the anatomical success results at the 1‐year follow‐up visit to pre‐ and intraoperative findings using multivariate statistical methods.

Results:  In the phakic subtrial, anatomical success was negatively associated with the number of breaks (p < 0.0001), break extension > 1 clock hour (p = 0.0005) and intraoperative use of cryotherapy (p = 0.0484). It was positively associated with retinal breaks with irregular edges (p = 0.0353) and subretinal fluid drainage (p = 0.0155). In the pseudophakic/aphakic subtrial, anatomical success was negatively associated with the number of retinal breaks (p = 0.0004) and previous YAG capsulotomy (p = 0.0256), and the combined effect of the surgical procedure and intraoperative use of laser (p = 0.0229).

Conclusion:  Primary anatomical success is an important result for patients undergoing RRD surgery. Our data demonstrate that the final anatomical outcome is related to a higher preoperative number of breaks and cryotherapy in phakic eyes. Additional risk factors varied between phakic and pseudophakic subgroups. Our findings may be used to facilitate the prognosis of future patients with RRD.
Antibiotic Use and Resistance in Animal Farming: A Quantitative and Qualitative Study on Knowledge and Practices among Farmers in Khartoum, Sudan
Authors: Eltayb A. , Barakat S. , Marrone G. , Shaddad S. , Stålsby Lundborg C.
Published: February 2012

Antibiotic resistance is a major emerging global public health threat. Farmers in the Khartoum state are believed to misuse antibiotics in animal farming leading to daily exposure to resistant bacteria and antibiotic residues. Hence, farmers are at potential risk exposure to bacteria, zoonotic infection and toxicity. We hypothesized that farmers’ misuse of antibiotics could be due to their ignorance of the importance of optimal use of antibiotics, the potential health hazards and the economical waste associated with antibiotic misuse practices. In the present study, we investigated knowledge and practices among farmers regarding antibiotic use and resistance. For this purpose, a cross‐sectional study was conducted in Khartoum state where data were collected from 81 farmers using structured interviews. Data were analysed both quantitatively and qualitatively. Fifty‐two per cent of farmers were uneducated or had studied for <6 years. The majority reported antibiotic use for treatment and prevention while only 5% stated use for growth promotion. Antibiotic group treatment for both sick and healthy animals was commonly practiced among most farmers. The most commonly used group of antibiotics was the quinolones, which was reported by one‐third. Only 30% of the farmers had heard of antibiotic resistance and provided their definition. Almost half were not aware of the commonly transferred zoonotic infections between humans and animals. The farmers consume 1–2 meals/day from their own farm products. A significant association between low education, poor knowledge of farmers on antibiotic use, antibiotic resistance and zoonotic infections was found. This association may play a vital role in the present practiced misuse of antibiotics. Our findings on farmers’ practices could be used as baseline information in defining the gaps related to antibiotic use and resistance in animal farming in Sudan. It can thus serve as a foundation for future interventions.
Discontinuities and Earnings Management: Evidence from Restatements Related to Securities Litigation*
Authors: Donelson Dain C. , Mcinnis John M. , Mergenthaler Richard D.
Published: February 2012

A heated debate exists as to whether discontinuities in earnings distributions are indicative of earnings management. While many studies attribute discontinuities in earnings distributions to earnings management, other studies argue that earnings discontinuities are artifacts of sample selection and research design. Overall, there is limited direct evidence of a connection between earnings discontinuities and earnings management. In this study, we provide direct evidence linking earnings management to earnings discontinuities for a sample of firms that settle securities class action lawsuits and restate earnings from the alleged GAAP violation period. We compare the distribution of restated (“unmanaged”) earnings to originally reported (“managed”) earnings. We find that discontinuities are not present in the distribution of analyst forecast errors and earnings changes using unmanaged earnings but are present using managed earnings. The discontinuity in the earnings level distribution is attenuated, but not eliminated, on an unmanaged basis. These shifts among our sample of firms are caused by earnings management and cannot be explained by sample selection or research design issues. Our findings are important because many studies use earnings discontinuities as a proxy for intentional earnings manipulations and we provide the first direct evidence of a link between these two phenomena.
Imaging findings of a haemangiosarcoma in a cervical vertebra of a horse
Authors: Raes E. V. , Durie I. , Wegge B. , Gielen I. , Vanderperren K. , Saunders J. H.
Published: February 2012

An 18‐year‐old Warmblood gelding was presented with a recent, abrupt onset of ataxia. Transcranial magnetic stimulation (TMS) was performed and revealed a delayed response in both thoracic and pelvic limbs. Radiographic examination of the cervical region demonstrated osteolytic lesions in the vertebral body and arch of the third cervical vertebra (C3). A cervical myelogram revealed spinal cord swelling in this region on the lateral projection. Computed tomographic (CT) myelography was performed, which showed osteolytic lesions and circumferential thinning of the contrast column due to extra‐dural compression at the cranial cervical region. These findings were compatible with an aggressive bone lesion compressing the spinal cord. Primary or secondary neoplasia and osteomyelitis were considered in the differential diagnosis. Because of the severity of the findings and poor prognosis, the horse underwent euthanasia. Post mortem histopathological diagnosis was a haemangiosarcoma involving the cranial cervical vertebrae and epidural space. This report demonstrates the additional value of CT myelography on the extent and exact location of cervical vertebral compressive lesions in the horse. This information can be useful for prognosis, biopsy and/or planned surgery of these lesions.
Equine peripheral blood‐derived mesenchymal stem cells: Isolation, identification, trilineage differentiation and effect of hyperbaric oxygen treatment
Authors: DHAR M. , NEILSEN N. , BEATTY K. , EAKER S. , ADAIR H. , GEISER D.
Published: February 2012

Reasons for performing study: Two studies report variability in proliferation and limited adipocyte differentiation of equine peripheral blood‐derived adult mesenchymal stem cells, thus casting doubt on their adipogenic potential. Peripheral blood can be a valuable source of adult mesenchymal stem cells if cell culture conditions permissive for their adherence, proliferation and differentiation are defined. Hyperbaric oxygen treatment has been reported to mobilise haematopoietic progenitor stem cells into the peripheral blood in humans and mice, but similar experiments have not been done in horses.

Objectives: To optimise cell culture conditions for isolation, propagation and differentiation of adult stem cells from peripheral blood and to assess the effect of hyperbaric oxygen treatment on adult stem cell concentrations.

Methods: Peripheral blood was collected from the jugular vein of 6 research mares, and mononuclear cells were isolated. They were subjected to cell culture conditions that promote the adherence and proliferation of adult stem cells. The cells were characterised by their adherence, expression of cellular antigen markers, and trans‐differentiation. Each horse was subjected to 3 hyperbaric oxygen treatments, and stem cells were compared before and after treatments. Stem cells derived from adipose tissue were used as controls.

Results: One‐third of the horses yielded viable stem cells from peripheral blood, positive for CD51, CD90 and CD105, and demonstrated osteocyte, chondrocyte and adipocyte differentiation. Hyperbaric oxygen treatment resulted in a significant increase in CD90‐positive cells. Horses that did not yield any cells pretreatment did so only after 3 hyperbaric oxygen treatments.

Conclusions and potential relevance: Peripheral blood can be a valuable source of adult stem cells, if one can identify reliable equine‐specific markers, provide methods to increase the number of circulating progenitor cells and optimise cell culture conditions for growth and viability. Our findings are important for further studies towards technological advances in basic and clinical equine regenerative medicine.
Optimization of Free Convection Heat Transfer From Vertical Plates Using Nanofluids
Authors: Corcione Massimo , Cianfrini Marta , Habib Emanuele , Quintino Alessandro
Published: February 2012

Free convection heat transfer in nanofluids from vertical flat plates at uniform temperature is investigated theoretically. The main idea upon which the present work is based is that nanofluids behave more like single-phase fluids rather than like conventional solid–liquid mixtures. This assumption implies that all the convective heat transfer correlations available in the literature for single-phase flows can be extended to nanoparticle suspensions, provided that the thermophysical properties appearing in them are the nanofluid effective properties calculated at the reference temperature. In this connection, two empirical equations, based on a wide variety of experimental data reported in the literature, are used for the evaluation of the nanofluid effective thermal conductivity and dynamic viscosity. Conversely, the other effective properties are computed by the traditional mixing theory. The heat transfer enhancement that derives from the dispersion of nanosized solid particles into the base liquid is calculated for different operating conditions, nanoparticle diameters, and combinations of solid and liquid phases. The fundamental result obtained is the existence of an optimal particle loading for maximum heat transfer. In particular, for any assigned combination of suspended nanoparticles and base liquid, it is found that the optimal volume fraction increases as the nanofluid average temperature increases, the nanoparticle size decreases, and the Rayleigh number of the base fluid decreases.
Numerical Analysis of Depollution of Smoke Produced by Household Wastes Incineration
Authors: N’Wuitcha K. , Banna M. , Igo S. W. , Zeghmati B. , Palm K. , Chesneau X.
Published: February 2012

This study reports the results on a numerical investigation of the depollution of smokes produced by the incineration of household wastes in a cylindrical furnace. Transfers are described by double-diffusive mixed convection equations, associated to radiative transfer equation, and a global kinetics model. The governing equations are discretized using finite volume method and the resulting algebraic equations are solved by THOMAS algorithm. The linkage between the pressure and velocity fields is assumed by SIMPLE algorithm. Results are presented as streamlines, isotherms, isoconcentrations for different Reynolds number (300 ≤ Re ≤ 1800). Effects of Reynolds number, relative height opening, aspect ratio, excess air ratio, and radiative transfers on gas pollutants (CO, CH4, C2H4…) destruction are investigated in detail.
Application of Pseudo-Poincaré Maps to Assess Gas Turbine System Health
Authors: Bassily Hany , Daqaq Mohammed F. , Wagner John
Published: February 2012

The transition between two operational modes in a dynamic system often occurs under strict measures such that repeatability is more a target than a metric for performance evaluations. The concept of Poincaré maps may be applied to health monitoring systems. In this paper, a diagnosis strategy based on Poincaré maps will be presented to evaluate dynamic systems’ behavior with application to power generating gas turbines based on the repeatability of the transition trajectories. Using this approach, extensive operating data for three 85 MW simple cycle power generating gas turbines were evaluated to assess and analyze their performance. The proposed strategy was capable of isolating failed starts; automatic unloads and load rejection events as major events during the test period. Results and conclusions drawn in this study regarding the health condition of the rotating equipment demonstrate the opportunity for system monitoring.
Evaluation of a Data Center Recirculation Non-Uniformity Metric Using Computational Fluid Dynamics
Authors: Demetriou Dustin W. , Khalifa H. Ezzat
Published: February 2012

The work presented in this paper is an extension of the companion work by the authors on a simplified thermodynamic model for data center optimization, in which a recirculation non-uniformity metric, θ, was introduced and used in a parametric analysis to highlight the deleterious effect of recirculation non-uniformity at the inlet of racks on the data center cooling infrastructure power consumption. In this work, several studies are done using a commercial computational fluid dynamics (CFD) package to verify many of the assumptions necessary in the development of the simplified model and to understand the degree of recirculation non-uniformity present in typical data center configurations. A number of CFD simulations are used to quantify the ability of the simple model at predicting θ. The results show that the simple model provides a fairly accurate estimate of θ, with a standard deviation in the prediction error of ∼10–15%. The CFD analysis are also to understand the effect of row length and server temperature rise (ΔTs) temperature non-uniformity. The simulations show that reasonable values of θ range from 2–6 for open aisle data centers depending on operating strategy and data center layout. As a means to understand the effect of buoyancy, a data center Archimedes number (Ar), the ratio of buoyancy to inertia forces, is introduced as a function of tile flow rate and server temperature rise. For servers with modest temperature rise (∼ 10.0°C), Ar is ∼0.1; however, for racks with large temperature rise (∼20°C), Ar > 1.0, meaning buoyancy needs to be considered important. Through CFD analysis the significant effect buoyancy has on the inlet rack temperature patterns is highlighted. The Capture Index (ψ), the ratio of cold air ingested by the racks to the required rack flow, is used to investigate its relationship to the ratio of server flow to tile flow (Y), as the inlet rack temperature patterns are changed by increased Ar. The results show that although the rack inlet temperature patterns are extremely different, ψ does not change significantly as a function of Ar. Lastly, the effect of buoyancy on the assumption of linearity of the temperature field is considered for a range of Ar. The results show the emergence of a stratified temperature pattern at the inlet of the racks as Ar increases and buoyancy becomes more important. It is concluded that under these conditions, a δT change in tile temperature does not produce a δT change in temperature everywhere in the field.
Development of a Compliant Nanothermal Interface Material
Authors: Shaddock David , Weaver Stanton , Chasiotis Ioannis , Shah Binoy , Zhong Dalong
Published: February 2012

The power density requirements continue to increase and the ability of thermal interface materials has not kept pace. Increasing effective thermal conductivity and reducing bondline thickness reduce thermal resistance. High thermal conductivity materials, such as solders, have been used as thermal interface materials. However, there is a limit to minimum bondline thickness in reducing resistance due to increased fatigue stress. A compliant thermal interface material is proposed that allows for thin solder bondlines using a compliant structure within the bondline to achieve thermal resistance <0.01 cm2C/W. The structure uses an array of nanosprings sandwiched between two plates of materials to match thermal expansion of their respective interface materials (ex. silicon and copper). Thin solder bondlines between these mating surfaces and high thermal conductivity of the nanospring layer results in thermal resistance of 0.01 cm2C/W. The compliance of the nanospring layer is two orders of magnitude more compliant than the solder layers so thermal stresses are carried by the nanosprings rather than the solder layers. The fabrication process and performance testing performed on the material is presented.
Cooling Performance Comparisons of Five Different Plate-Pin Compound Heat Sinks Based on Two Different Length Scale
Authors: Zhou Feng , Geb David , Catton Ivan
Published: February 2012

Plate fin heat sinks (PFHS) are widely used to remove heat from the microelectronic devices. In the present study, a new type of compound heat sink, named as plate-pin fin heat sink (PPFHS), is employed to improve the air cooling performance. With CFD numerical method, PPFHSs with five forms of pin cross-section profiles (square, circular, elliptic, NACA 0050, and dropform) and PFHS were simulated. Two different length scales were adopted to evaluate the performance of six types of heat sinks, including PFHS. One of the length scales is commonly used by many investigators, which is two times of the channel spacing. The other length scale is suggested by volume averaging theory (VAT), which is four times of average porosity divided by specific interface. The influence of pin fin cross-section profile on the flow and heat transfer characteristics was presented by means of Nusselt number, pressure drop and overall efficiency. It is found that the Nu number of a PPFHS is at least 35% higher than that of a PFHS used to construct the PPFHS at the same Reynolds number no matter which length scale was used. It is also revealed that the heat transfer enhancement of square PPFHS is offset by its excessively high pressure drop, which makes it not as efficient as the other types of PPFHS. Circular PPFHS performs similar to the streamline shaped PPFHS when the Reynolds number is not too high. However, with the increase in Re the advantage of the circular cross-section diminishes. Using the streamline shaped pins, not only the pressure drop of the compound heat sinks could be decreased considerably, the heat transfer enhancement also makes a step forward. However, evaluating the performance of heat sinks by using the commonly used length scale, the benefit of streamline shaped types of PPFHSs is a little bit overstated. The VAT suggested length scale is more reasonable to do the performance comparison of different heat sinks, especially when it is difficult to provide a fair and physically meaningful basis for the comparison. In short, the present numerical simulation provides original information of the influence of different pin-fin cross-section profiles on the thermal and hydraulic performance of the new type compound heat sink and emphasizes the importance of choosing a proper length scale when evaluating heat transfer enhancement, which is helpful in the design of heat sinks.
An Experimentally Validated Model for Transport in Thin, High Thermal Conductivity, Low CTE Heat Spreaders
Authors: Ranjan Ram , Murthy Jayathi Y. , Garimella Suresh V. , Altman David H.
Published: February 2012

Passive phase-change thermal spreaders such as vapor chambers have been widely employed to spread the heat from small-scale high-flux heat sources to larger areas. In the present work, a numerical model for ultra-thin vapor chambers has been developed which is suitable for reliable predictions of the operation at high heat fluxes and small scales. The effects of boiling in the wick structure on the thermal performance are modeled and the model predictions are compared with experiments on custom-fabricated devices. The model predictions agree reasonably well with experimental measurements and reveal the input parameters to which thermal resistance and vapor chamber capillary limit are most sensitive.
Submerged Jet Impingement Boiling on a Polished Silicon Surface
Authors: Mani Preeti , Cardenas Ruander , Narayanan Vinod
Published: February 2012

Submerged jet impingement boiling has the potential to enhance pool boiling heat transfer rates. In most practical situations, the surface could consist of multiple heat sources that dissipate heat at different rates resulting in a surface heat flux that is non-uniform. This paper discusses the effect of submerged jet impingement on the wall temperature characteristics and heat transfer for a non-uniform heat flux. A mini-jet is caused to impinge on a polished silicon surface from a nozzle having an inner diameter of 1.16 mm. A 25.4 mm diameter thin-film circular serpentine heater, deposited on the bottom of the silicon wafer, is used to heat the surface. Deionized degassed water is used as the working fluid and the jet and pool are subcooled by 20°C. Voltage drop between sensors leads drawn from the serpentine heater are used to identify boiling events. Heater surface temperatures are determined using infrared thermography. High-speed movies of the boiling front are recorded and used to interpret the surface temperature contours. Local heat transfer coefficients indicate significant enhancement upto radial locations of 2.6 jet diameters for a Reynolds number of 2580 and upto 6 jet diameters for a Reynolds number of 5161.
Single-Step Fabrication and Characterization of Ultrahydrophobic Surfaces With Hierarchical Roughness
Authors: Dash Susmita , Kumari Niru , Dicuangco Mercy , Garimella Suresh V.
Published: February 2012

Hydrophobic surfaces with microscale roughness can be rendered ultrahydrophobic by the addition of sub-micron scale roughness. A simple yet highly effective concept of fabricating hierarchical structured surfaces using a single-step deep reactive ion etch process is proposed. Using this method the complexities generally associated with fabrication of two-tier roughness structures are eliminated. Experiments are conducted on two double-roughness surfaces with different surface roughness, achieved by varying the size of the microscale roughness features. The surfaces are characterized in terms of static contact angle and roll-off angle and compared with surfaces consisting of only single-tier microscale roughness. The robustness of the new hierarchical roughness surfaces is verified through droplet impingement tests. The hierarchical surfaces are more resistant to wetting than the single roughness surfaces and show higher coefficients of restitution for droplets bouncing off the surface. The droplet dynamics upon impingement are explored.
Stress-Induced and Electro-Migration of Electroplated Copper Thin Film Interconnections Used for 3D Integration
Authors: Saito Naoki , Murata Naokazu , Tamakawa Kinji , Suzuki Ken , Miura Hideo
Published: February 2012

Electroplated copper thin films have started to be applied to not only interconnections in printed wiring boards, but also thin film interconnections and TSV (Through Silicon Via) in semiconductor devices because of its low electric resistivity and high thermal conductivity. Thus, the electrical reliability of the electroplated copper interconnections was investigated experimentally. Self-made electroplated copper thin film interconnections were used for the evaluation. Electroplating conditions are as follows. The thin film interconnections were made by damascene process for electromigration tests. The applied current density during the test was varied from 1 MA/cm2 to 10 MA/cm2. Abrupt fracture caused by the local fusion was often observed in the as-electroplated interconnections within a few hours during the test. Since there were a lot of porous grain boundaries in the as-electroplated thin films, the local high Joule heating should have caused the fusion at one of the porous grain boundaries. Actually, it was confirmed that the failure rate increased linearly with the square of the amplitude of the applied current density. However, the diffusion of copper atoms caused by electromigration was enhanced significantly when the film was annealed at 400°C. Many voids and hillocks were observed on their surfaces. This change of the fracture mode clearly indicates the improvement of the crystallographic quality of the annealed film. It was also observed that the stress-induced migration was activated substantially in the annealed film. Large voids and hillocks grew during the custody of the film even at room temperature without any application of current. This stress-induced migration was caused by the increase of residual tensile stress of about 200 MPa in the annealed film. It was also found that sulfur atoms segregated in the grown hillocks, though no sulfur atoms were found by EDX in the initial as-electroplated interconnections or other area in the annealed thin film interconnections. Thus, the hillock formation in the annealed interconnections was enhanced by the segregation of sulfur atoms. These sulfur atoms should have been introduced into the electroplated films during electroplating. Therefore, it is very important to control the micro texture, the residual stress and the concentration of sulfur in the electroplated copper thin film interconnections to assure the stable life, in other words, to eliminate their sudden brittle fracture and time-dependent degradation caused by the residual stress in the thin film interconnections.