bluuebunny/crossref_metadata_2025 huggingface dataset:
The wound/burn guidelines – 6: Guidelines for the management of burns
Authors: Yoshino Yuichiro , Ohtsuka Mikio , Kawaguchi Masakazu , Sakai Keisuke , Hashimoto Akira , Hayashi Masahiro , Madokoro Naoki , Asano Yoshihide , Abe Masatoshi , Ishii Takayuki , Isei Taiki , Ito Takaaki , Inoue Yuji , Imafuku Shinichi , Irisawa Ryokichi , Ohtsuka Masaki , Ogawa Fumihide , Kadono Takafumi , Kawakami Tamihiro , Kukino Ryuichi , Kono Takeshi , Kodera Masanari , Takahara Masakazu , Tanioka Miki , Nakanishi Takeshi , Nakamura Yasuhiro , Hasegawa Minoru , Fujimoto Manabu , Fujiwara Hiroshi , Maekawa Takeo , Matsuo Koma , Yamasaki Osamu , Le Pavoux Andres , Tachibana Takao , Ihn Hironobu ,   The Wound/Burn Guidelines Committee
Published: March 2016

Burns are a common type of skin injury encountered at all levels of medical facilities from private clinics to core hospitals. Minor burns heal by topical treatment alone, but moderate to severe burns require systemic management, and skin grafting is often necessary also for topical treatment. Inappropriate initial treatment or delay of initial treatment may exert adverse effects on the subsequent treatment and course. Therefore, accurate evaluation of the severity and initiation of appropriate treatment are necessary. The Guidelines for the Management of Burn Injuries were issued in March 2009 from the Japanese Society for Burn Injuries as guidelines concerning burns, but they were focused on the treatment for extensive and severe burns in the acute period. Therefore, we prepared guidelines intended to support the appropriate diagnosis and initial treatment for patients with burns that are commonly encountered including minor as well as moderate and severe cases. Because of this intention of the present guidelines, there is no recommendation of individual surgical procedures.
Associations Between Alcohol Consumption and Leukocyte Telomere Length Modified by a Common Polymorphism of ALDH2
Authors: Shin Chol , Baik Inkyung
Published: March 2016

Background

Data on the association between alcohol consumption and telomere length, a marker of biological aging, are inconsistent. Moreover, the genetic modification of this association has been reported only rarely. To evaluate the association between alcohol consumption and leukocyte telomere length (LTL), and the effect modification of this association by a common polymorphism of the aldehyde dehydrogenase 2 (ALDH2) gene, we conducted a cross‐sectional study in a general population including 1,771 middle‐aged and elderly Koreans, aged 49 to 79 years.

Methods

Study participants provided blood samples between 2011 and 2012 for the LTL assay, and between 2001 and 2002 for genomewide genotyping. Between 2011 and 2012, they also completed a questionnaire‐based interview regarding their alcohol consumption. We examined effect modification by rs2074356, a surrogate marker of the ALDH2 polymorphism.

Results

Heavy alcohol consumption (average daily alcohol consumption of >30 g) was inversely associated with LTL only among carriers of the mutant alleles (CT and TT) of rs2074356 (p < 0.01). Among these subjects, elderly drinkers in particular showed the strongest association (p < 0.001). Light‐to‐moderate alcohol consumption on an almost daily basis was positively associated with LTL (p < 0.001), and this association was significant among carriers of the wild‐type allele (CC) of rs2074356 (p < 0.01) but not among those with the mutant alleles.

Conclusions

Our findings suggest that the potential benefit of light‐to‐moderate alcohol consumption and the detriment of heavy alcohol consumption on biological aging may depend on ALDH2 polymorphism.
Deconstructing the nature of episodic foresight deficits associated with chronic opiate use
Authors: Mercuri Kimberly , Terrett Gill , Bailey Phoebe E. , Henry Julie D. , Curran Helen Valerie , Rendell Peter G.
Published: March 2016

Objectives

Episodic foresight refers to the capacity to mentally travel forward in time and has been linked to a wide variety of important functional behaviours. Evidence has recently emerged that chronic opiate use is associated with deficits in this critical capacity and that these difficulties are not simply a secondary consequence of broader cognitive dysfunction. The current study aimed to better understand the circumstances in which chronic opiate users might be expected to have problems with episodic foresight, by addressing whether deficits reflect compromised scene construction, self‐projection, or narrative ability.

Methods

Thirty‐five chronic opiate users and 35 demographically matched controls completed an imagination task in which they were instructed to imagine and provide descriptions of an atemporal event, a plausible, self‐relevant future event, as well as complete a narrative task. These three imagination conditions systematically varied in their demands on scene construction, self‐projection, and narrative ability.

Results

Consistent with prior literature, chronic opiate users exhibited reduced capacity for episodic foresight relative to controls. However, this study was the first to show that these difficulties were independent of capacity for scene construction and narration. Instead, a specific impairment in self‐projection into the future appears to contribute to the problems with episodic foresight seen in this clinical group.

Conclusions

Deficits in self‐projection into the future may have important implications in therapeutic environments given that many relapse prevention strategies rely heavily on the ability to project oneself into an unfamiliar future, free of problem substance use.

Practitioner points

A reduced capacity for episodic foresight highlights the importance of refining current relapse prevention protocols that place significant demands for mental time travel into the future.

Psychosocial treatments should focus on the attainment of more immediate or short‐term goals.

It is difficult to delineate the effects of specific substances given long‐standing drug use history common to chronic opiate users.

Conclusions relating to neurological functioning are speculative given the absence of neuroimaging data.
Treatment of erosive oral lichen planus with methotrexate
Authors: Lajevardi Vahideh , Ghodsi Seyedeh Zahra , Hallaji Zahra , Shafiei Zahra , Aghazadeh Nessa , Akbari Zahra
Published: March 2016

Background and objectives

Erosive oral lichen planus (EOLP) is a chronic inflammatory disease of the oral mucosa causing significant pain and impairment of the quality of life. No immediate and definitive cure is available, especially in its chronic and most recalcitrant forms. The objective of this study was to evaluate the efficacy of methotrexate treatment in EOLP.

Patients and methods

A prospective open trial of oral methotrexate 15 mg QWK in 18 patients with EOLP (clinically and histopathologically confirmed) unresponsive to at least one previous topical or systemic medication. Duration: Twelve weeks followed by twelve weeks of follow‐up.

Results

Partial response or better was achieved in 15 (83.3 %) patients. A statistically significant reduction in Thongprasom scale score was observed (mean value 5 at baseline, 3.08 ± 1.11 at week 12, 2.94 ± 0.97 at week 24, P value < 0.001). A statistically significant reduction was noted in the pain visual analogue scale (mean value 6.55 ± 2.33 at baseline, 2.46 ± 2.18 at week 12, 2.29 ± 1.93 at week 24, P value < 0.001). Adverse events occurred in four (22.2 %) patients, requiring discontinuation of treatment in one patient.

Conclusion

Methotrexate is a valuable therapeutic option in longstanding recalcitrant EOLP, particularly with respect to the improvement of subjective symptoms. Randomized controlled trials are required.
Guidelines on dermatomyositis – excerpt from the interdisciplinary S2k guidelines on myositis syndromes by the German Society of Neurology
Authors: Sunderkötter Cord , Nast Alexander , Worm Margitta , Dengler Reinhard , Dörner Thomas , Ganter Horst , Hohlfeld Reinhard , Melms Arthur , Melzer Nico , Rösler Kai , Schmidt Jens , Sinnreich Michael , Walter Maggi C. , Wanschitz Julia , Wiendl Heinz
Published: March 2016

The present guidelines on dermatomyositis (DM) represent an excerpt from the interdisciplinary S2k guidelines on myositis syndromes of the German Society of Neurology (available at www.awmf.org). The cardinal symptom of myositis in DM is symmetrical proximal muscle weakness. Elevated creatine kinase, CRP or ESR as well as electromyography and muscle biopsy also provide important diagnostic clues. Pharyngeal, respiratory, cardiac, and neck muscles may also be affected. Given that approximately 30 % of patients also develop interstitial lung disease, pulmonary function tests should be part of the diagnostic workup. Although the cutaneous manifestations in DM are variable, taken together, they represent a characteristic and crucial diagnostic criterion for DM. Approximately 5–20 % of individuals exhibit typical skin lesions without any clinically manifest muscle involvement (amyopathic DM). About 30 % of adult DM cases are associated with a malignancy. This fact, however, should not delay the treatment of severe myositis.

Corticosteroids are the therapy of choice in myositis (1–2 mg/kg). Additional immunosuppressive therapy is frequently required (azathioprine, for children methotrexate). In case of insufficient therapeutic response, the use of intravenous immunoglobulins is justified. The benefit of rituximab has not been conclusively ascertained yet. Acute therapeutic management is usually followed by low‐dose maintenance therapy for one to three years. Skin lesions do not always respond sufficiently to myositis therapy. Effective treatment for such cases consists of topical corticosteroids and sometimes also calcineurin inhibitors. Systemic therapies shown to be effective include antimalarial agents (also in combination), methotrexate, and corticosteroids. Intravenous immunoglobulins or rituximab may also be helpful. UV protection is an important prophylactic measure.
Identification of candidate genes in atopic dermatitis based on bioinformatic methods
Authors: Ding Yingguo , Shao Xia , Li Xiaomin , Zhai You , Zhang Yu , Wang Su , Fang Hong
Published: March 2016

Background

Atopic dermatitis (AD) is a chronic or relapsing inflammatory disorder of the skin that frequently precedes asthma and allergic disorders. This study aimed to identify candidate genes related to AD using bioinformatic methods.

Methods

The microarray data of GSE32924, including 12 nonlesional AD (ANL) and 13 lesional AD (AL) skin samples obtained from 14 patients with AD as well as eight other normal human skin samples, was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened in ANL and AL skin samples compared with normal controls, followed by gene ontology (GO) and pathway enrichment analyses. Furthermore, the selected overlapping DEGs were analyzed to identify co‐expressed genes, and a co‐expression network was established. GeneCodis database was selected for functional annotation of the differentially co‐expressed genes and a regulatory network was constructed.

Results

Compared with normal controls, 438 DEGs were identified in ANL skin samples and were mainly enriched in two pathways and the GO terms associated with epidermis development. Besides, 779 DEGs were identified in AL skin samples and were mainly enriched in four pathways and GO terms associated with immune response. Stimulated by retinoic acid 13 (STRA13), presenilin enhancer gamma secretase subunit (PSENEN), and nucleosome assembly protein 1‐like 2 (NAP1L2) were significantly enriched by integration analysis of the co‐expression and regulatory network.

Conclusion

Genes STRA13, PSENEN, and NAP1L2 were presumed to play critical roles in AD and they may serve as potential targets for the treatment of AD.
Reconstructing ancient Mediterranean crossroads in Deronectes diving beetles
Authors: García‐Vázquez David , Bilton David T. , Alonso Rocío , Benetti Cesar J. , Garrido Josefina , Valladares Luis F. , Ribera Ignacio
Published: March 2016

Aim

To reconstruct the evolutionary history of a genus of freshwater beetle with a pan‐Mediterranean distribution, to test classic hypotheses which proposed a Miocene origin for groups with high biodiversity in the Iberian and Anatolian peninsulas.

Location

Mediterranean basin.

Methods

We sequenced four mitochondrial and one nuclear gene from 51 specimens of 30 of the c. 60 extant species of Deronectes (Dytiscidae), all typical of mid‐mountain streams from North Africa and Iberia over most of Europe to the Middle East. We used maximum likelihood, Bayesian probabilities with an a priori evolutionary rate and a dispersal–extinction–cladogenesis model to reconstruct their biogeographical history.

Results

Deronectes has two major lineages which originated in the mid Miocene; one including mostly eastern and another mainly western and central Mediterranean species. From these two areas, range expansions, mainly at the end of the Miocene and beginning of the Pliocene, resulted in the many species groups and some of the extant species of the genus. Most of the current diversity and distributions are, however, of Plio‐Pleistocene origin, particularly in widespread European species.

Main conclusions

In line with traditional hypotheses, we found an ancient division between eastern and western Mediterranean lineages of Deronectes, likely resulting from the isolation of Europe west of the Alps from the Balkans and Anatolia during the early‐middle Miocene. The history of the genus was strongly influenced by major geological and climatic events, with successive cycles of fragmentation and subsequent eastward and westward range expansions, resulting in a steady accumulation of species across the basin. Most of these range movements took place through the north side of the Mediterranean, with only local displacements in the south during the Messinian salinity crisis and a recent (Pleistocene) colonization of the Italian Peninsula, which remained largely submerged through most of the genus’ evolutionary history.
The effect of area and isolation on insular dwarf proboscideans
Authors: van der Geer Alexandra A. E. , van den Bergh Gerrit D. , Lyras George A. , Prasetyo Unggul W. , Due Rokus Awe , Setiyabudi Erick , Drinia Hara
Published: March 2016

Aim

We investigated the hypothesis that insular body size of fossil elephants is directly related to isolation and surface area of the focal islands.

Location

Palaeo‐islands worldwide.

Methods

We assembled data on the geographical characteristics (area and isolation) of islands and body size evolution of palaeo‐insular species for 22 insular species of fossil elephants across 17 islands.

Results

Our results support the generality of the island rule in the sense that all but one of the elephants experienced dwarfism on islands. The smallest islands generally harbour the smallest elephants. We found no support for the hypothesis that body size of elephants declines with island isolation. Body size is weakly and positively correlated with island area for proboscideans as a whole, but more strongly correlated for Stegodontidae when considered separately. Average body size decrease is much higher when competitors are present.

Main conclusions

Body size in insular elephants is not significantly correlated with the isolation of an island. Surface area, however, is a significant predictor of body size. The correlation is positive but relatively weak; c. 23% of the variation is explained by surface area. Body size variation seems most strongly influenced by ecological interactions with competitors, possibly followed by time in isolation. Elephants exhibited far more extreme cases of dwarfism than extant insular mammals, which is consistent with the substantially more extended period of deep geological time that the selective pressures could act on these insular populations.
Understanding MOOC students: motivations and behaviours indicative of MOOC completion
Authors: Pursel B.K. , Zhang L. , Jablokow K.W. , Choi G.W. , Velegol D.
Published: March 2016

Massive open online courses (MOOCs) continue to appear across the higher education landscape, originating from many institutions in the USA and around the world. MOOCs typically have low completion rates, at least when compared with traditional courses, as this course delivery model is very different from traditional, fee‐based models, such as college courses. This research examined MOOC student demographic data, intended behaviours and course interactions to better understand variables that are indicative of MOOC completion. The results lead to ideas regarding how these variables can be used to support MOOC students through the application of learning analytics tools and systems.
The Lived Experience of Childbearing From Survivors of Sexual Abuse: “It Was the Best of Times, It Was the Worst of Times”
Authors: LoGiudice Jenna A. , Beck Cheryl T.
Published: March 2016

Introduction

In the United States, one in every 5 women will experience sexual violence. Survivors are at risk for difficult pregnancies, substance abuse, stress, fear, and preterm births. A history of sexual abuse can impact several aspects of a woman's childbirth, thereby affecting her long‐term physical and emotional well‐being. The adverse pregnancy outcomes, combined with the prevalence of sexual abuse, underscore the need for research to understand survivors’ experiences.

Methods

This study's purpose was to understand the lived experience of pregnancy, labor, and birth from survivors. A qualitative, descriptive phenomenological research design was utilized. The purposeful sample included 8 female, self‐identifying survivors of sexual abuse with at least one childbearing experience.

Results

Analysis identified 302 significant statements that formed 7 overarching themes: 1) No one asked me. Just ask me!; 2) An emotional roller coaster: From excitement to grief for what could have been a better experience; 3) All of a sudden I was that little girl again and/or I compartmentalized it: The all‐or‐nothing experience; 4) Am I even here?: Nothing was explained and I had no voice; 5) All too familiar: No support, nowhere to turn; 6) Holding on to the choices I can make: Who my doctor is and how I feed my baby; and 7) Overprotection: Keeping my child safe.

Discussion

The final result was the essence of childbearing for survivors in this study. They were not screened for a history of sexual abuse. Enjoyment and excitement were juxtaposed with guilt and fear. They had no voice, lacked support, and overwhelmingly desired control. They overprotected their children, from infancy into adulthood. The childbearing experience was a complex, emotional roller coaster permeated by the past. Women's health care providers can utilize the results to provide therapeutic care to survivors to prevent revictimization. The results elucidate the importance of screening for a history of sexual abuse and discussing the implications such a history can have on the childbearing experience.
Reducing Complexity by Creating Complexity: A Systems Theory Perspective on How Organizations Respond to Their Environments
Authors: Schneider Anselm , Wickert Christopher , Marti Emilio
Published: March 2016

Organizations have to cope with the complexity of their environment in order to survive. A considerable body of research has shown that organizations may respond to environmental complexity by creatinginternal complexity– for example, by expanding internal structures and processes. However, researchers know less about how organizations createcollaborative complexitycollectively – for example, by establishing alliances or developing common standards. This paper uses social systems theory to explore how organizations collaborate in response to complexity and to analyse the conditions under which they create either internal or collaborative complexity (or both) to address environmental complexity. It also examines how these types of complexity feed back into environmental complexity. To illustrate our conceptual model, we use corporate social responsibility (CSR).
The Impact of Core/Veneer Thickness Ratio and Cyclic Loading on Fracture Resistance of Lithium Disilicate Crown
Authors: Nawafleh Noor , Hatamleh Muhanad M. , Öchsner Andreas , Mack Florian
Published: March 2016

Purpose

To investigate the effect of core/veneer thickness ratio on the fracture strength of lithium disilicate crowns subjected to cyclic loading in a simulated oral environment.

Materials and Methods

A typodont molar tooth received a standard complete crown preparation according to the manufacturer's instructions. Sixty lithium disilicate crowns were prepared and assigned to three groups with the following core/veneer thickness ratios A: 0.7 (0.6/0.9), B: 1.1 (0.8/0.7), and C: 2 (1.0/0.5). The cores were milled from lithium disilicate e.max CAD blocks and hand‐layered using e.max Ceram. Ten specimens from each group acted as control, while the remaining ten specimens were subjected to thermal mechanical loading in a chewing simulator. All specimens were then subjected to the single load to fracture test at 1 mm/min crosshead speed. Data were analyzed using two‐way ANOVA, Tukey multiple comparison test, Pearson correlation test, and quadratic regression (p < 0.05).

Results

All crowns survived fatigue testing with no signs of fractures or chipping, resulting in a 100% survival rate. The mean fracture load values for control and corresponding fatigued specimens (N) were 1075 and 987 for group A, 1548 and 1482 for group B, and 1455 and 1163 for group C. Increasing the core/veneer thickness ratio from 0.7 to 1.1 significantly increased the fracture load of the crowns; however, a further increase in the ratio up to 2 did not affect the fracture load compared to the 1.1 ratio (p > 0.05). The increase in core thickness significantly positively correlated with the fracture force for control specimens (r = 0.76; p < 0.05). After single load to fracture, crowns predominantly failed by bulk fracture, including the whole thickness of the crowns. Fracture modes were categorized according to fracture path and number of fractured pieces.

Conclusions

Crowns with a 1.1 (0.8/0.7) core/veneer thickness ratio showed the optimum fracture load among control and fatigued groups. Reducing the core thickness from 0.8 mm to 0.6 mm decreased the fracture load significantly, while increasing it to 1.0 mm showed no statistical effect. Cyclic loading in a simulated oral environment did not significantly affect fracture strength of veneered lithium disilicate crowns in any of the tested groups.
A guide through a family of phylogenetic dissimilarity measures among sites
Authors: Pavoine Sandrine
Published: March 2016

Ecological studies have now gone beyond measures of species turnover towards measures of phylogenetic and functional dissimilarity. This change of perspective has a main objective: disentangling the processes that drive species distributions from local to broad scales. A fundamental difference between phylogenetic and functional analyses is that phylogeny is intrinsically dependent on a tree‐like structure whereas functional data can, most of time, only be forced to adhere a tree structure, not without some loss of information. When the branches of a phylogenetic tree have lengths, then each evolutionary unit on these branches can be considered as a basic entity on which dissimilarities among sites should be measured. Several of the recent measures of phylogenetic dissimilarities among sites thus are traditional dissimilarity indices where species are replaced by evolutionary units. The resulting indices were named PD‐dissimilarity indices, in reference to early work on the phylogenetic diversity (PD) measure. Here I review and compare indices and ordination approaches that, although first developed to analyse the differences in the species compositions of sites, can be adapted to describe PD‐dissimilarities among sites. Using simulations of species distributions along environmental gradients, I compare indices, associated with permutation tests and null models, in their ability to reveal existing phylogenetic patterns along the gradients. As an illustration, I show that the amount of bat PD‐dissimilarities along a disturbance gradient in Selva Lacandona of Chiapas, Mexico is dependent on whether species' abundance is considered, and on the PD‐dissimilarity index used. Overall, the family of PD‐dissimilarity indices has a critical potential for future analyses of phylogenetic diversity as it benefits from decades of research on the measure of species dissimilarity. I provide clues to help to choose among many potential indices, identifying which indices satisfy minimal basic properties, and analysing their sensitivity to abundance, size, diversity and joint absences.
Modulation of IL‐12 and IFNγ by probiotic supplementation promotes protection against Toxocara canis infection in mice
Authors: de Avila L. F. d. C. , de Leon P. M. M. , de Moura M. Q. , Berne M. E. A. , Scaini C. J. , Leivas Leite F. P.
Published: March 2016

In this study, supplementation with the probiotic Saccharomyces boulardii promoted a reduction in intensity of infection by Toxocara canis and modulates cytokines mRNA expression in experimentally infected mice. IL‐12 gene transcription had 40‐fold increase in S. boulardii supplemented uninfected mice and sevenfold increase in supplemented infected mice comparing with not supplemented group. Regarding IFNγ, similar results were observed, since probiotic supplementation induced approximately 43‐fold increase, but only in uninfected mice (P < 0·05). T. canis infection upregulated IL‐10 expression while S. boulardii downregulated it and no change was observed for IL‐4. Thus, based in these findings; we suggest that one possible mechanism responsible for S. boulardii protection effect against T. canis infection is by the modulation of cytokines expression, especially IL‐12.
Managing Demand Uncertainty through Core Acquisition in Remanufacturing
Authors: Mutha Akshay , Bansal Saurabh , Guide V. Daniel R.
Published: March 2016

We discuss the optimal raw material acquisition strategy for a third party remanufacturer (3PR). We specifically investigate whether a 3PR should acquire used products or cores in bulk with uncertain quality levels, or in sorted grades with known quality levels; and whether to acquire and remanufacture cores before the demand is realized (planned acquisition), or after the demand is realized (reactive acquisition), or on both occasions (sequential acquisition). When only sorted cores are acquired, we find that, (i) it is optimal to acquire cores in multiple grades to balance acquisition and remanufacturing costs; (ii) if reactive acquisition is possible, it reduces the assortment size (number of grades in which cores are acquired) and the total inventory acquired in the planned acquisition; and (iii) the optimal portfolio of grades to acquire and the optimal acquisition and remanufacturing quantities of these grades can be determined analytically. When bulk cores are acquired in addition to sorted cores, the property of reduction in assortment size of the planned acquisition is preserved. We also show that the 3PR should acquire only a fraction of the demand in planned acquisition, and leave the rest for reactive acquisition. This fraction changes during the lifecycle of a remanufactured product. Using a combination of empirical and realistic data from a smartphone remanufacturer we show that sequential acquisition increases expected profit by up to 8% and 27% over only planned and only reactive acquisitions respectively, and reduces the inventory acquired by up to 21% over only planned acquisition.
Optical Analysis of a Two Stage XX Concentrator for Parametric Trough Primary and Tubular Absorber With Application in Solar Thermal Energy Trough Power Plants
Authors: Núnez Bootello Juan Pablo , Price Henry , Silva Pérez Manuel , Doblaré Castellano Manuel
Published: March 2016

A new symmetric nonimaging parametric trough collector (PmTC) for an evacuated circular receiver is proposed having an absorber diameter of 70 mm similar to the LS3/Eurotrough absorber one, and a circular secondary. The optical design method is explained and a sensitivity analysis is conducted with respect to the diameter of the secondary and to the acceptance angle. In the design process, transmission, absorption, and reflection losses are neglected. A secondary mirror radius of 145 mm and an acceptance angle of ±14 mrad were chosen as realistic values. For these values a concentrator geometry having 8.7 m gross aperture and 100% intercept factor for rays impinging on the primary within the referred acceptance angle is obtained producing a net concentration ratio relative to the thermodynamic ideal limit of 0.52 compared to 0.31 for traditional parabolic trough collectors. The new concentrator is composed of a primary discontinuous reflector with two symmetrical portions with parametric geometry, and a central parabolic portion located between the other two. The ensemble secondary receiver can be dressed up with the secondary concentrator manufactured by partially mirroring a diameter adapted glass tube—either internally or externally—or alternatively by means of a commercial evacuated receiver and an independent 145 mm radius arc of circumference external secondary reflector. Monte Carlo ray-tracing results show that only 15% of the rays undergo secondary reflection before arriving to the absorber and a sharp angle transmission curve. The new concentrator is proposed for application in solar thermal energy (STE) trough power plants.
Identification of the Thermophysical Properties of the Soil by Inverse Problem
Authors: Mansour Salwa , Canot Édouard , Muhieddine Mohamad
Published: March 2016

This paper introduces a numerical strategy to estimate the thermophysical properties of a saturated porous medium (volumetric heat capacity (ρC)s, thermal conductivity λs, and porosity ϕ), where a phase change problem (liquid/vapor) appears due to strong heating. The estimation of these properties is done by inverse problem knowing the heating curves at selected points of the medium. To solve the inverse problem, we use both the damped Gauss Newton (DGN) and the Levenberg Marquardt methods to deal with high nonlinearity of the system and to tackle the problem with large residuals. We use the method of lines where time and space discretizations are considered separately. Special attention has been paid to the choice of the regularization parameter of the apparent heat capacity (AHC) method which may prevent the convergence of the inverse problem.
Computation of Mixed Convection and Volumetric Radiation in Vertical Channel Based on Hybrid Thermal Lattice Boltzmann Method
Authors: Derfoufi Soufiane , Moufekkir Fayçal , Mezrhab Ahmed
Published: March 2016

The present paper presents a numerical study of mixed convection coupled with volumetric radiation in a vertical channel. The geometry of the physical model consists of two isothermal plates. The governing equations of the problem are solved using a hybrid scheme of the lattice Boltzmann method (LBM) and finite-difference method (FDM). The main objective of this study is to evaluate the influence of the Richardson number (Ri) and the emissivity of the walls (εi) on the heat transfer, on the flow, and on the temperature distribution. Results show that Richardson number and emissivity have a significant effect on heat transfer and air flow.
Three-Dimensional Steady and Oscillatory Natural Convection in a Rectangular Enclosure With Heat Sources
Authors: Bouraoui Amin , Bessaïh Rachid
Published: March 2016

In this paper, a numerical study of three-dimensional (3D) natural convection air-cooling of two identical heat sources, simulating electronic components, mounted in a rectangular enclosure was carried out. The governing equations were solved by using the finite-volume method based on the SIMPLER algorithm. The effects of Rayleigh number Ra, spacing between heat sources d, and aspect ratios Ax in x-direction (horizontal) and Az in z-direction (transversal) of the enclosure on heat transfer were investigated. In steady state, when d is increased, the heat transfer is more important than when the aspect ratios Ax and Az are reduced. In oscillatory state, the critical Rayleigh numbers Racr for different values of spacing between heat sources and their aspect ratios, at which the flow becomes time dependent, were obtained. Results show a strong relation between heat transfers, buoyant flow, and boundary layer. In addition, the heat transfer is more important at the edge of each face of heat sources than at the center region.
Effective Thermal Conductivity of a Wet Porous Medium—Presence of Hysteresis When Modeling the Spatial Water Distribution for the Pendular Regime
Authors: Canot Édouard , Delannay Renaud , Mansour Salwa , Muhieddine Mohamad , March Ramiro
Published: March 2016

This paper deals with the heat transfer between two spherical grains separated by a small gap; dry air is located around the grains and a liquid water meniscus is supposed to be present between them. This problem can be seen as a microscale cell of an assembly of solid grains, for which we are looking for the effective thermal conductivity. For a fixed contact angle and according to the volume of the liquid meniscus, two different shapes are possible for the meniscus, giving a “contacting” state (when the liquid makes a true bridge between the two spheres) and a “noncontacting” one (when the liquid is split in two different drops, separated by a thin air layer); the transition between these two states occurs at different times when increasing or decreasing the liquid volume, thus leading to a hysteresis behavior when computing the thermal flux across the domain.
Experimental and Numerical Investigation of Inlet Dimple in Point and Elliptical Contact Elastohydrodynamic Lubrication Films
Authors: Wang Xuefeng , Hu Rufu , Wang Mingjun , Yao Huanxin
Published: March 2016

The experimental observation of the inlet dimple of the elastohydrodynamic lubrication (EHL) film was carried out in point and elliptical contacts, respectively, and then, the numerical analysis under point contacts was conducted. The inlet dimple appears and then moves upstream toward the inlet and finally disappears with the increase of the entrainment speed. In the meantime, the dimple depth increases at the beginning and then decreases. The high load leads to a wide entrainment speed range where dimple exists. The varying range of the entrainment speed corresponding to the dimple appearance is smaller at a smaller included angle between the minor axis of elliptical contact and the entrainment direction.
Estimating the Thermal Radiative Properties of Shading Nets Under Natural Outdoor Conditions
Authors: Abdel-Ghany Ahmed M. , Al-Helal Ibrahim M. , Shady M. R.
Published: March 2016

The perforated nature of nets makes it impossible to measure the thermal radiative properties (emittance, εn, transmittance, τn, and reflectance, ρn) correctly by using any measuring device under natural conditions. In this study, a theoretical model was developed and validated to predict εn, τn, and ρn precisely by solving the model equations simultaneously. The net was tacked onto a wooden frame; thermal radiation balance was applied below and above the net surfaces and above a black substrate underneath the frame. The downward and upward thermal radiation fluxes were measured below and above the net to be used as input parameters to the simulation. Nets with different porosities (ϕ) and colors were used for the study. The results showed that the estimated εn ranged from 0.41 to 0.82 and τn ranged from 0.16 to 0.55 for the nets tested, whereas the reflectances were very low (ρn≤0.08). The color and porosity together affect the properties of the net. Even though under equilibrium conditions of a net with the surrounding environment, the emittance of the net is equal to its absorptance. However, the absorbed thermal radiation by the net dose not equal to the emitted radiation and the difference is a convected heat.
Droplet Departure Characteristics and Dropwise Condensation Heat Transfer at Low Steam Pressure
Authors: Wen Rongfu , Lan Zhong , Peng Benli , Xu Wei , Ma Xuehu , Cheng Yaqi
Published: March 2016

Dropwise condensation has received significant attention due to its great potential to enhance heat transfer by the rapid droplet removal. In this work, droplet departure characteristics on a vertical surface, especially the droplet departure retention at low steam pressure and its effect on the heat transfer performance are investigated experimentally. The energy dissipation increases during droplet movement due to the increased viscosity at low pressure. Droplet oscillation caused by excess kinetic energy weakens and the dynamic contact angle (CA) hysteresis becomes apparent, which is not beneficial to droplet departure. Condensed droplets grow larger and fall more slowly at low pressure compared to that at atmospheric pressure. The droplet moves smoothly downward once it grows to departure size at atmospheric pressure while the droplet exhibits an intermittent motion at low pressure. Based on the droplet departure characteristics, a unified heat transfer model for dropwise condensation is developed by introducing the pressure-dependent departure velocity. The modified model very well predicts heat transfer performances at various pressures and the nonlinearity of heat flux varying with surface subcooling is quantitatively explained. This work provides insights into the heat transfer mechanism of dropwise condensation and offers a new avenue to further enhance heat transfer at low steam pressure.
Transient Modeling of a Capillary Pumped Loop for Terrestrial Applications
Authors: Blet Nicolas , Platel Vincent , Ayel Vincent , Bertin Yves , Romestant Cyril
Published: March 2016

Improvement of a new design for a capillary pumped loop (CPL) ensuring high-dissipation electronics cooling in ground transportation has been carried out over recent years. Experimental studies on the hybrid loop, which share some characteristics with the standard CPL and loop heat pipe (LHP), have underlined the sizable potential of this new system, particularly with regard to its upcoming industrial applications. In order to obtain a reliable tool for sizing and design of this CPL for terrestrial applications (CPLTA), the present transient thermohydraulic modeling has been developed. Based on the nodal method, the model's originality consists of transcribing balance equations under electrical networks by analogy. The model's validation is provided by experimental results from a new CPLTA bench with three parallel evaporators. Large-scale numerical evaluation of loop behavior in a gravity field with a single evaporator shall facilitate understanding of the different couplings between loop parts. In addition, modeling of a multi-evaporator loop is introduced and compared with recent experimental results.
Numerical Solution of Mixed Thermal Elastohydrodynamic Lubrication in Point Contacts With Three-Dimensional Surface Roughness
Authors: Wang Xiaopeng , Liu Yuchuan , Zhu Dong
Published: March 2016

Elastohydrodynamic lubrication (EHL) is a common mode of fluid-film lubrication in which many machine elements operate. Its thermal behavior is an important concern especially for components working under extreme conditions such as high speeds, heavy loads, and surfaces with significant roughness. Previous thermal EHL (TEHL) studies focused only on the cases with smooth surfaces under the full-film lubrication condition. The present study intends to develop a more realistic unified TEHL model for point contact problems that is capable of simulating the entire transition of lubrication status from the full-film and mixed lubrication all the way down to boundary lubrication with real machined roughness. The model consists of the generalized Reynolds equation, elasticity equation, film thickness equation, and those for lubricant rheology in combination with the energy equation for the lubricant film and the surface temperature equations. The solution algorithms based on the improved semi-system approach have demonstrated a good ability to achieve stable solutions with fast convergence under severe operating conditions. Lubricant film thickness variation and temperature rises in the lubricant film and on the surfaces during the entire transition have been investigated. It appears that this model can be used to predict mixed TEHL characteristics in a wide range of operating conditions with or without three-dimensional (3D) surface roughness involved. Therefore, it can be employed as a useful tool in engineering analyses.
Improvement of Tribological Behaviors by Optimizing Concave Texture Shape Under Reciprocating Sliding Motion
Authors: Zhang Hui , Dong Guang-neng , Hua Meng , Chin Kwai-Sang
Published: March 2016

An analytical numerical model to optimize the shape of concave surface texture for the achievement of low friction in reciprocating sliding motion has been developed. The model uses: (i) average Reynolds equation to evaluate friction coefficient and (ii) genetic algorithm (GA) to optimize and obtain several preferable texture shapes. Analysis of distribution contour maps of hydrodynamic pressure gives the possible mechanisms involved. Moreover, experimental comparisons of tribological performances between the optimized and the circular textures were conducted to verify the simulation results. It is shown that surface textures of the elliptical and fusiform shapes can effectively enhance the load bearing capacity and reduce the friction coefficient compared with circular textures. The increase in hydrodynamic pressure for these optimized texture shapes is considered to be the major mechanism responsible for improving their tribological performance. Experimental results confirm that the elliptical-shaped textures have preferable tribological behaviors of low friction coefficient under the operating condition of light load.
Low-Constraint Toughness Testing of Two Single-Edge Notched Tension Methods in a Single Specimen
Authors: Park Dong-Yeob , Gravel Jean-Philippe , Hari Manoj Simha C. , Liang Jie , Duan Da-Ming
Published: March 2016

Single-edge notched tension (SE(T) or SENT) specimens have been increasingly proposed as a low-constraint toughness test to measure toughness of line pipe materials, as the crack tip constraint approximates a circumferential surface flaw in a pipe under loading. The clamped SE(T) single-specimen procedures recently developed by Shen and Tyson (2008, “Fracture Toughness Evaluation of High Strength Steel Pipe,” ASME Paper No. PVP2008-61100; 2008, “Development of Procedure for Low-Constraint Toughness Testing Using a Single-Specimen Technique,” CANMET Materials Technology Laboratory, Technical Report No. 2008-18 (TR)) and Tang et al. (2010, “Development of the SENT Test of Strain-Based Design of Welded Pipelines,” 8th International Pipeline Conference, IPC 2010, Calgary, AB, Canada) have both used in common the use of a clamped single-specimen of similar geometry and relied on the unloading compliance technique for crack size estimation. In the former case, a single clip gauge is attached to the integral knife edge and the crack-tip opening displacement (CTOD) is estimated by means of a J-integral-to-CTOD conversion, similar to the procedure of ASTM E1820-11. The latter uses a pair of clip gauges mounted on an attachable raised set of knife edges to estimate CTOD at the original crack tip position by a triangulation rule. Consolidating these two sets of clip gauges in a specimen makes direct comparisons of two SE(T) methods under identical test conditions: material, specimen geometry, equipment, test temperature, and operator (Weeks et al., 2013, “Fracture Toughness Instrumentation Techniques for Single-Specimen Clamped SE(T) Tests on X100 Linepipe Steel: Experimental Setup,” 6th Pipeline Technology Conference, Ostend, Belgium). In this study, SE(T) testing employing these two SE(T) methods on a single specimen was conducted on B × B shallow-cracked (a/W ∼ 0.35) specimens of two X70 pipeline girth welds. This paper discusses details of the two SE(T) methods and techniques on the same specimen.
Adaptive Microslip Projection for Reduction of Frictional and Contact Nonlinearities in Shrouded Blisks
Authors: Mitra Mainak , Zucca Stefano , Epureanu Bogdan I.
Published: March 2016

Reduced order models (ROMs) of turbine bladed disks (blisks) are essential to quickly yet accurately characterize vibration characteristics and effectively design for high cycle fatigue. Modeling blisks with contacting shrouds at adjacent blades is especially challenging due to friction damping and localized nonlinearities at the contact interfaces which can lead to complex stick–slip behavior. While well-known techniques such as the harmonic balance method (HBM) and Craig–Bampton component mode synthesis (CB-CMS) have generally been employed to generate ROMs in the past, they do not reduce degrees-of-freedom (DoFs) at the interfaces themselves. In this paper, we propose a novel method to obtain a set of reduction basis functions for the contact interface DoFs as well as the remaining DoFs called “adaptive microslip projection” (AMP). The method is based on analyzing a set of linear systems with specifically chosen boundary conditions on the contact interface. Simulated responses of full order baseline models and the novel ROMs under various conditions are studied. Results obtained from the ROMs compare very favorably with the baseline model. This study addresses the case of a shrouded blisk in microslip close to stick. The AMP procedure may be possibly applied to other systems with Coulomb friction contacts, but its accuracy and effectiveness will need to be evaluated separately.
Skeletal Muscle and Physical Activity in Portuguese Community-Dwelling Older Adults
Authors: Gouveia Élvio R. , Gouveia Bruna R. , Maia José A. , Blimkie Cameron. J. , Freitas Duarte L.
Published: March 2016

The aims of this study were to describe age- and sex-related differences in total body skeletal muscle (TB-SM) mass and to determine the variance explained by physical activity (PA). This cross-sectional study included 401 males and 402 females, aged 60–79 years. TB-SM was determined by dual-energy x-ray absorptiometry (DXA) and PA by Baecke questionnaire. Statistical analysis included t test, ANOVAs, Pearson correlations, and multiple regression analysis. TB-SM mass was higher in the youngest age group when compared with the oldest in males and females. Males had greater TB-SM values than females. PA made a significant and positive contribution to the variation in TB-SM, β = 0.071; p = .016. Sex, height, fat mass, and PA explained 77% of the variance in TB-SM. The oldest cohorts and females had lower TB-SM than the younger cohorts and males. This study suggests that PA exerts a significant role in the explanation of TB-SM.
Sensorimotor Peripheral Nerve Function and Physical Activity in Older Men
Authors: Lange-Maia Brittney S. , Cauley Jane A. , Newman Anne B. , Boudreau Robert M. , Jakicic John M. , Glynn Nancy W. , Zivkovic Sasa , Dam Thuy-Tien L. , Caserotti Paolo , Cawthon Peggy M. , Orwoll Eric S. , Strotmeyer Elsa S. , _ _
Published: March 2016

We determined whether sensorimotor peripheral nerve (PN) function was associated with physical activity (PA) in older men. The Osteoporotic Fractures in Men Study Pittsburgh, PA, site (n = 328, age 78.8 ± 4.7 years) conducted PN testing, including: peroneal motor and sural sensory nerve conduction (latencies, amplitudes: CMAP and SNAP for motor and sensory amplitude, respectively), 1.4g/10g monofilament (dorsum of the great toe), and neuropathy symptoms. ANOVA and multivariate linear regression modeled PN associations with PA (Physical Activity Scale for the Elderly [PASE] and SenseWear Armband). After multivariable adjustment, better motor latency was associated with higher PASE scores (160.5 ± 4.8 vs. 135.6 ± 6.7, p < .01). Those without versus with neuropathy symptoms had higher PASE scores (157.6 ± 5.3 vs. 132.9 ± 7.1, p < .01). Better versus worse SNAP was associated with slightly more daily vigorous activity (9.5 ± 0.8 vs. 7.3 ± 0.7, p = .05). Other PN measures were not associated with PA. Certain PN measures were associated with lower PA, suggesting a potential pathway for disability.