bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactive oxygen species and uncoupling protein 2 in pancreatic β‐cell function
Authors: Pi J. , Collins S.
Published: October 2010

Growing evidence indicates that reactive oxygen species (ROS) are not just deleterious by‐products of respiratory metabolism in mitochondria, but can be essential elements for many biological responses, including in pancreatic β‐cells. ROS can be a ‘second‐messenger signal’ in response to hormone/receptor activation that serves as part of the ‘code’ to trigger the ultimate biological response, or it can be a ‘protective signal’ to increase the levels of antioxidant enzymes and small molecules to scavenge ROS, thus restoring cellular redox homeostasis. In pancreatic β‐cells evidence is emerging that acute and transient glucose‐dependent ROS contributes to normal glucose‐stimulated insulin secretion (GSIS). However, chronic and persistent elevation of ROS, resulting from inflammation or excessive metabolic fuels such as glucose and fatty acids, may elevate antioxidant enzymes such that they blunt ROS and redox signalling, thus impairing β‐cell function. An interesting mitochondrial protein whose main function appears to be the control of ROS is uncoupling protein 2 (UCP2). Despite continuing investigation of the exact mechanism by which UCP2 is ‘activated’, it is clear that UCP2 levels and/or activity impact the efficacy of GSIS in pancreatic islets. This review will focus on the paradoxical roles of ROS in pancreatic β‐cell function and the regulatory role of UCP2 in ROS signalling and GSIS.
The hypoxia response pathway and β‐cell function
Authors: Cantley J. , Grey S. T. , Maxwell P. H. , Withers D. J.
Published: October 2010

β‐cells sense glucose and secrete appropriate amounts of insulin by coupling glucose uptake and glycolysis with quantitative ATP production via mitochondrial oxidative pathways. Therefore, oxidative phosphorylation is essential for normal β‐cell function. Multiple cell types adapt to hypoxia by inducing a transcriptional programme coordinated by the transcription factor hypoxia‐inducible factor (HIF). HIF activity is regulated by the von Hippel–Lindau (Vhl) protein, which targets the HIFα subunit for proteasomal degradation in the presence of oxygen. Several recent studies have shown that Vhl deletion in β‐cells results in Hif1α activation, impaired glucose‐stimulated insulin secretion (GSIS) and glucose intolerance. This was found to be because of alterations in β‐cell gene expression inducing a switch from aerobic glucose metabolism to anaerobic glycolysis, thus disrupting the GSIS triggering pathway. Situations in which islets may become hypoxic are discussed, in particular islet transplantation which has been reported to cause islet hypoxia because of an inadequate blood supply post‐transplant. Aside from this principal role for HIF in negatively regulating β‐cell glucose sensing, other aspects of hypoxia signalling are discussed including β‐cell differentiation, development and vascularization. In conclusion, recent studies clearly show that hypoxia response mechanisms can negatively impact on glucose sensing mechanisms in the β‐cell and this has the potential to impair β‐cell function in a number of physiological and clinical situations.
Causes and cures for endoplasmic reticulum stress in lipotoxic β‐cell dysfunction
Authors: Cnop M. , Ladrière L. , Igoillo‐Esteve M. , Moura R. F. , Cunha D. A.
Published: October 2010

Pancreatic β‐cell dysfunction is central to the pathogenesis of type 2 diabetes, and the loss of functional β‐cell mass in type 2 diabetes is at least in part secondary to increased β‐cell apoptosis. Accumulating evidence suggests that endoplasmic reticulum (ER) stress is present in β‐cells in type 2 diabetes. Free fatty acids (FFAs) cause ER stress and are putative mediators of β‐cell dysfunction and death. In this review, we discuss the molecular mechanisms underlying ER stress induced by saturated and unsaturated FFAs. Oleate and palmitate trigger ER stress through ER Ca2+ depletion and build‐up of unfolded proteins in the secretory pathway. Saturated and unsaturated FFAs elicit a differential signal transduction in the three branches of the ER stress response, resulting in different survival/apoptosis outcomes. The protection of β‐cells against FFAs through the interference with ER stress signalling has opened novel therapeutic perspectives for type 2 diabetes. Chemical chaperones, salubrinal and glucagon‐like peptide‐1 (GLP‐1) analogues have been used to protect β‐cells from lipotoxic ER stress. Importantly, the pro‐ and antiapoptotic effects of these compounds are cell and context dependent.
Restoring endoplasmic reticulum function by chemical chaperones: an emerging therapeutic approach for metabolic diseases
Authors: Engin F. , Hotamisligil G. S.
Published: October 2010

The endoplasmic reticulum (ER) is a eukaryotic organelle that plays important roles in protein synthesis, folding and trafficking, calcium homoeostasis and lipid and steroid synthesis. It is the major protein synthesis compartment for secreted, plasma membrane and organelle proteins. Perturbations of ER homeostasis such as the accumulation of unfolded or misfolded proteins cause ER stress. To alleviate this stress, ER triggers an evolutionarily conserved signalling cascade called the unfolded protein response (UPR). As an initial response, the UPR aims at adapting and restoring ER function by translational attenuation, upregulation of ER chaperones and degradation of unfolded proteins. However, if the ER function is severely impaired because of excessive or prolonged exposure to stress, then the inflicted cells may undergo programmed cell death. During ER stress, unstable or partially folded mutant proteins are prevented from trafficking to their proper subcellular localizations and usually rapidly degraded. The small molecules named chemical chaperones help to stabilize these mutant proteins and facilitate their folding and proper trafficking from the ER to their final destinations. Because increasing number of studies suggest that ER stress is involved in a number of disease pathogenesis including neurodegenerative diseases, cancer, obesity, diabetes and atherosclerosis, promoting ER folding capacity through chemical chaperones emerges as a novel therapeutic approach. In this review, we provide insight into the many important functions of chemical chaperones during ER stress, their impact on the ER‐stress‐related pathologies and their potential as a new drug targets, especially in the context of metabolic disorders.
Reexamining the Workplace Justice to Outcome Relationship: Does Frame of Reference Matter?
Authors: Bernerth Jeremy , Walker H. Jack
Published: October 2010

abstract

Using a combination of self‐interest and deontological theories as justification, we propose a demarcated view of workplace justice that separates justice for an individual (personal justice) and inferred assessments of justice for organizational members (third party justice). Results of two studies confirmed the appropriateness of separate justice measures and demonstrated differential effects on key criteria based on the relevancy (personal or joint) of the outcome in question. Specifically, Studies 1 and 2 found that personal justice was a better predictor of organizational commitment and turnover intentions while third party justice was more closely related to workplace cohesion (Study 1), citizenship behaviours (Study 2), and deviance behaviours (Study 2). Implications of these findings and future research needs are discussed.
Anatomy in ancient India: a focus on the Susruta Samhita
Authors: Loukas Marios , Lanteri Alexis , Ferrauiola Julie , Tubbs R. Shane , Maharaja Goppi , Shoja Mohammadali Mohajel , Yadav Abhishek , Rao Vishnu Chellapilla
Published: October 2010

This review focuses on how the study of anatomy in India has evolved through the centuries. Anatomical knowledge in ancient India was derived principally from animal sacrifice, chance observations of improperly buried human bodies, and examinations of patients made by doctors during treatment. The Vedic philosophies form the basis of the Ayurvedic tradition, which is considered to be one of the oldest known systems of medicine. Two sets of texts form the foundation of Ayurvedic medicine, the Susruta Samhita and the Charaka Samhita. The Susruta Samhita provided important surgical and anatomical information of the understanding of anatomy by Indians in the 6th century BCE. Here we review the anatomical knowledge known to this society.
Episodic growth of zircon in UHP orthogneisses from the North Dabie Terrane of east‐central China: implications for crustal architecture of a collisional orogen
Authors: XIE Z. , CHEN J.‐F. , CUI Y.‐R.
Published: October 2010

Zircon U‐Pb dating of three orthogneiss samples from the North Dabie terrane (NDT) is undertaken in order to reconstruct their formation and evolutionary histories, and also the crustal architecture of the Dabie orogen after Triassic subduction and exhumation. SHRIMP zircon U‐Pb dating, in combination with back scattered electron (BSE) imaging and Laser Raman spectrometry, provides accurate identification of the core, mantle and rim structure for zircon growth during protolith formation and overgrowth during subduction/exhumation and post‐collisional metamorphism. Concordant U‐Pb ages of 760–730 Ma and high Th/U ratios of >0.4 are obtained for relict oscillatory zoning fields of inherited cores that were not metamictized. These features suggest that these ages represent the time of magmatic protolith formation during the breakup of Rodinia. The overgrown mantle domains around the metamictized cores are clean with few mineral inclusions (e.g. quartz, garnet and apatite). Mantle domains have low Th/U ratios of <0.1 and yielded U‐Pb ages of 215–205 Ma, which are slightly younger than the known ages of peak ultrahigh‐pressure (UHP) metamorphism, suggesting that overgrowth took place during initial exhumation. The ages are similar to the time of retrograde metamorphism of the UHP orthogneisses in the Central Dabie terrane (CDT). Overgrown rims are also clean, with a few mineral inclusions of apatite and quartz. They yield two groups of U‐Pb ages, 138–137 Ma and 124–120 Ma. The former is considered to be the time of onset of orogenic extension and tectonic collapse, whereas the latter falls into the age range of widespread magmatism in the Dabie orogen, and is regarded as the time of extension climax that resulted in intensive anatexis of the crust. Whole‐rock Sr‐Nd isotope analyses of four orthogneisses show εNd(t) values of −1.2 to −15 and ISr values >0.719, similar to the values obtained from UHP orthogneisses in the CDT. It is concluded that, as with the CDT, the orthogneisses with episodic zircon growths from the NDT should also be a part of the exhumed slice following the continental deep subduction. However, the orthogneisses in this study were buried at a lower level in the orogenic crust compared with those of the CDT prior to the Cretaceous magmatism. Therefore, the orthogneisses from the NDT were affected by the Cretaceous magmatism whereas the CDT orthogneisses were not affected.
State‐of‐the‐Art in Longitudinal Studies on Aging: An Overview of the Supplement
Authors: Tappen Ruth M. , Ouslander Joseph G.
Published: October 2010

The articles in this supplement are based on a conference held in January 2008 sponsored by a grant from the Robert Wood Johnson Foundation. The purpose of the conference was to summarize major findings and methodological issues in previous and ongoing longitudinal studies on aging and to identify potentially fruitful areas for future research. This article is a review and synthesis of the articles in this supplement. Each of the articles makes important contributions to summarizing existing research, identifying challenging methodological issues, or proposing areas that should be explored in future research. Three themes were identified: general improvement in the health status of the population aged 65 and older in the United States, a shift in longitudinal research on aging from a focus on the endpoints of disease to a focus on the preclinical stage and underlying mechanisms of these diseases, and contemporary developments in longitudinal research methodology. A number of practical suggestions were also drawn from the articles reviewed.
Translating Research to Promote Healthy Aging: The Complementary Role of Longitudinal Studies and Clinical Trials
Authors: Guralnik Jack M. , Kritchevsky Stephen B.
Published: October 2010

An important challenge in epidemiology is the difficulty in inferring causality from observational studies. Even the best longitudinal studies have limitations in this regard, and when clinical trials are feasible, they will provide more‐definite evidence of causality, but even when clinical trials are feasible, a large amount can be learned about the disease process, assessment techniques, subject selection criteria, and the effect of potential interventions from longitudinal studies. This review covers the theoretical issues supporting the value and limitations of longitudinal studies, the practical utilization in clinical trials of different aspects of knowledge that can be gained from longitudinal studies, critical issues in the translation of longitudinal observational studies into clinical trials, and the value of observational studies in broadening the applicability of specific trials. Relevant issues are illustrated with examples of unsuccessful and successful trials, with a major emphasis on clinical trials of physical activity in older persons.
Screening in Frail Older People: An Ounce of Prevention or a Pound of Trouble?
Authors: Clarfield A. Mark
Published: October 2010

Screening for subclinical disease has provided benefit to many asymptomatic patients, especially those who are relatively young and otherwise healthy. However, frail older people do not always profit from such maneuvers, for several reasons. First, older individuals usually have less physiological reserve and greater comorbidity and resultant polypharmacy than their younger counterparts. As such, they may tolerate the invasive interventions called for after a positive screening test less easily. In addition, shorter natural life expectancy shifts the focus to quality of life improvement after screening tests rather than simply offering a promise of “more years.” Lack of education and cognitive decline may also interfere with the older person's ability to give truly informed consent to these maneuvers. Thus, on the whole, in this rapidly growing subpopulation, screening programs may tilt the balance toward the likelihood of causing more harm than good. For many frail older patients, an individualized approach to screening is recommended, adjusted to comorbidity, life expectancy, and patient preference. One size does not fit all.
Predictive Health: The Imminent Revolution in Health Care
Authors: Brigham Kenneth L.
Published: October 2010

Increasing social, economic, and political pressures to reform the U.S. approach to medical care makes change likely. A fundamental premise of predictive health is that it should be cheaper (at least per person life‐year) and more efficient and have a greater return on the investment of keeping people healthy as opposed to waiting for disease to intervene. The Emory Predictive Health and Society Strategic Initiative and its Center for Health Discovery and Well Being have embarked on a program to define health to the extent that modern science permits in the context of the entire human experience, to identify measurable variables that describe and predict a healthy state, and to use that knowledge to design health‐focused interventions that are affordable and effective. Initial results from a study of a randomly selected “essentially healthy” cohort, using extensive assessments and a health partner, are promising. Studies of healthy aging over the entire life spectrum promise valuable normative data for age‐specific assessments of health and the setting of realistic health goals.
Towards Evidence‐based Management: Creating an Informative Database of Nursing‐Sensitive Indicators
Authors: Patrician Patricia A. , Loan Lori , McCarthy Mary , Brosch Laura R. , Davey Kimberly S.
Published: October 2010

Purpose: The purpose of this paper is to describe the creation, evolution, and implementation of a database of nursing‐sensitive and potentially nursing‐sensitive indicators, the Military Nursing Outcomes Database (MilNOD). It discusses data quality, utility, and lessons learned.

Design/Methods: Prospective data collected each shift include direct staff hours by levels (i.e., registered nurse, other licensed and unlicensed providers), staff categories (i.e., military, civilian, contract, and reservist), patient census, acuity, and admissions, discharges, and transfers. Retrospective adverse event data (falls, medication errors, and needle‐stick injuries) were collected from existing records. Annual patient satisfaction, nurse work environment, and pressure ulcer and restraint prevalence surveys were conducted.

Findings and Conclusions: The MilNOD contains shift level data from 56 units in 13 military hospitals and is used to target areas for managerial and clinical performance improvement. This methodology can be modified for use in other healthcare systems.

Clinical Relevance: As standard tools for evidence‐based management, databases such as MilNOD allow nurse leaders to track the status of nursing and adverse events in their facilities.
Vitamin K2 modulates differentiation and apoptosis of both myeloid and erythroid lineages
Authors: Sada Eriko , Abe Yasunobu , Ohba Rie , Tachikawa Yoshimichi , Nagasawa Eriko , Shiratsuchi Motoaki , Takayanagi Ryoichi
Published: October 2010

Vitamin K2 (VK2) can improve cytopenia in some patients with myelodysplastic syndrome (MDS). Although it is well known that VK2 induces differentiation and apoptosis in acute myeloid leukemia (AML) cell lines, little is known about its effect on normal hematopoietic progenitors. The effects of VK2 on primary myeloid and erythroid progenitors were examined. Mobilized CD34‐positive cells from peripheral blood were used for the examination of myeloid lineage cells, and erythroid progenitors purified from peripheral blood were used for erythroid lineage cells. VK2 upregulated the expressions of myeloid markers CD11b and CD14, and increased the mRNA expression levels of CCAAT/enhancer binding protein‐α (C/EBPα) and PU.1 in myeloid progenitors. In erythroid progenitors, VK2 did not show a significant effect on differentiation. However, VK2 exhibited an anti‐apoptotic effect on erythroid progenitors under erythropoietin depletion. This anti‐apoptotic effect was restricted to normal erythroid progenitors and was not shown in erythroleukemic cell line AS‐E2. Steroid and xenobiotic receptor (SXR), which was recently identified as a receptor of VK2, was expressed on myeloid progenitors, and the SXR agonist rifampicin (RIF) also upregulated CD11b and CD14 expressions on myeloid progenitors. These results indicate that SXR is involved in the effect of VK2 on myeloid progenitors. The major effect of VK2 on myeloid progenitors was promoting differentiation, whereas its anti‐apoptotic effect seemed to be dominant in erythroid progenitors. Although the detailed mechanism of VK2’s effect on differentiation or apoptosis of hematopoietic progenitors remains unknown, the effect of VK2 therapy in patients with MDS could be partly explained by these mechanisms.
CXCR7: a new SDF‐1‐binding receptor in contrast to normal CD34+ progenitors is functional and is expressed at higher level in human malignant hematopoietic cells
Authors: Tarnowski Maciej , Liu Rui , Wysoczynski Marcin , Ratajczak Janina , Kucia Magda , Ratajczak Mariusz Z.
Published: October 2010

CXCR7 was identified as another stromal‐derived factor‐1 (SDF‐1)‐binding receptor that also binds the interferon‐inducible T‐cell chemoattractant (I‐TAC), and we became interested in its potential role in migration/adhesion of normal hematopoietic stem/progenitor cells (HSPCs) as well as selected leukemia cell lines. To address this normal human bone marrow‐, umbilical cord blood‐, and mobilized peripheral blood‐derived cells as well as 16 selected human leukemic cell lines were phenotyped for CXCR7 expression. The expression of CXCR7 in hematopoietic cell lines was analyzed at transcriptional level. The biologic significance of CXCR7 expression was subsequently tested in signal transduction studies as well as in in vitro proliferation and chemotactic assays. We noted that CXCR7 is expressed at very low levels (approximately 3–6%) in normal human CD34+ cells isolated from bone marrow, umbilical cord blood, and mobilized peripheral blood. More importantly, when we employed I‐TAC, which activates CXCR7, but not CXCR4, we did not observe any chemotactic responsiveness in human clonogenic progenitors. As expected, I‐TAC also did not affect clonogenic growth of human CD34+ cells. In contrast, functional CXCR7, whose expression is regulated in an NF‐κΒ‐dependent manner, as we report here, is highly expressed in several human myeloid malignant cell lines. I‐TAC‐induced activation of CXCR7 in human hematopoietic cell lines leads to phosphorylation of MAPKp42/44 and AKT, and enhanced cell adhesion and slightly cell migration. In conclusion, CXCR7 is expressed at very low level on normal human HSPCs and does not play a direct role in their proliferation or slightly cell migration; however, in contrast, it is involved in trafficking/adhesion of human leukemic cells.
The Multiple Facets of Ubiquitination in the Regulation of Notch Signaling Pathway
Authors: Le Bras Stéphanie , Loyer Nicolas , Le Borgne Roland
Published: October 2010

The Notch signaling pathway regulates numerous aspects of metazoan development and tissue renewal. Deregulation or loss of Notch signaling is associated with a wide range of human disorders from developmental syndromes to cancer. Notch receptors and their ligands are widely expressed throughout development, yet Notch activation is robustly controlled in a spatio‐temporal manner. Within the past decades, genetic screens and biochemical approaches led to the identification of more than 10 E3 ubiquitin ligases and deubiquitinating enzymes implicated in the regulation of the Notch pathway. In this review, we highlight the recent studies in Notch signaling that reveal how ubiquitination of components of the Notch pathway, ranging from degradation to regulation of membrane trafficking, impacts on the developmental control of the signaling activities of both Notch receptors and their ligands.
Parental support for newborn screening for cystic fibrosis
Authors: de Monestrol Isabelle , Brucefors Agneta Bergsten , Sjöberg Birgitta , Hjelte Lena
Published: October 2010

Aim:  To describe the attitudes among parents towards including cystic fibrosis (CF) in the newborn screening programme and towards the potential knowledge of their own carrier status.

Methods:  A questionnaire with three to five response categories and an information leaflet was posted to 143 CF parents, 3 matched diabetes and 3 matched population parents, the response rate being 85%, 74% and 70%, respectively. Comparisons between groups were made with statistical tests for independent groups.

Results:  Eighty‐six percent of CF, 70% of diabetes and 77% of population parents were in favour of newborn screening for CF, 47%, 45% and 50%, respectively, wished to know their CF carrier status. The parental attitude was independent of the age of the child, as well as delay of diagnosis and well‐being of the CF child at the time of diagnosis. Sixty percent of the CF parents experienced the diagnosis as delayed.

Conclusion:  Parents in Sweden support CF newborn screening. Half of the parents wanted to know their CF carrier status.
Parental perception of overweight and underweight in children and adolescents
Authors: Júlíusson Pétur B , Roelants Mathieu , Markestad Trond , Bjerknes Robert
Published: October 2010

Aims:  To compare the parental perception of overweight and underweight in their children to objective criteria, based on body mass index (BMI), waist circumference and triceps skinfold thickness, and to explore the effects of potential determinants.

Methods:  Logistic regression of anthropometric measurements, socio‐demographic characteristics and self‐reported parental height and weight on the parental perception of their child’s weight status in 3770 children aged 2–19.

Results:  Seventy per cent of overweight/obese children and 40.8% of underweight children were perceived having normal weight by parents. In 2‐ to 5‐year‐old overweight children, 91.2% were considered to have normal weight. For a given BMI, primary school age children, adolescents and girls had a higher probability to be assigned as overweight, whereas adolescents and girls had a lower probability to be assigned as underweight. Overweight parents more readily assigned their children as underweight, but there was no effect of parental educational level or parental underweight.

Conclusion:  Parental ability to recognize overweight or underweight in their offspring was generally poor. The findings emphasize the need for objective criteria based on physical measurements in the routine follow up of children, as parental ability to recognize weight problems in their children is nonreliable.
Insights into Strata Use of Forest Animals Using the ‘Canopy Effect’
Authors: Voigt Christian C.
Published: October 2010

Stable carbon isotope ratios (δ13C) of plants increase linearly from ground to canopy. Accordingly, I used δ13C for estimating strata use of fig‐eating bats. Data suggest that, overall, bats commuted at lower but fed at higher forest strata, and that small bats foraged at lower forest strata than large bats.
Low‐Dose Statin Therapy Improves Endothelial Function in Type 2 Diabetic Patients With Normal Serum Total Cholesterol: A Randomized Placebo‐Controlled Study
Authors: Adel Amr , Abdel‐Salam Zainab , Nammas Wail
Published: October 2010

J Clin Hypertens (Greenwich). 2010;12:820‐825. © 2010 Wiley Periodicals, Inc.

The authors sought to explore the effect of low‐dose atorvastatin on endothelial function in normocholesterolemic patients with type 2 diabetes mellitus without evidence of coronary disease. Sixty patients with type 2 diabetes mellitus, normal serum cholesterol, and normal exercise test results were enrolled. Initial assessment was performed by measurement of the brachial artery diameter and flow velocity both at baseline and after induced hyperemia. Patients were randomly assigned to receive either atorvastatin 10 mg daily for 4 weeks (atorvastatin group=30 patients) or matched placebo for the same period (placebo group=30 patients). Follow‐up assessment of the brachial artery diameter and flow velocity (both baseline and hyperemic) was performed after 4 weeks. Initially, no significant difference was found between the two groups regarding brachial artery diameter or flow velocity, both at baseline and at peak hyperemia (P>.05 for all). At follow‐up, there was a significantly higher flow velocity at baseline (P<.05) and a significantly higher percent increase of brachial artery diameter (from baseline to peak hyperemia) in the atorvastatin group (P<.05). In patients with type 2 diabetes mellitus and normal serum cholesterol without evidence of coronary disease, low‐dose atorvastatin improves endothelial function.
Proline metabolism in the moderately halophilic bacterium Halobacillus halophilus: differential regulation of isogenes in proline utilization
Authors: Köcher Saskia , Tausendschön Michaela , Thompson Melanie , Saum Stephan H. , Müller Volker
Published: October 2010

The amino acid proline is not only synthesized as a compatible solute but also used as a carbon and energy source by the moderately halophilic bacterium Halobacillus halophilus. Growth on proline was not affected by the salinity of the medium. Proline was degraded by proline dehydrogenase (ProDH) and Δ1‐pyrroline‐5‐carboxylate dehydrogenase (P5CDH) to glutamate via Δ1‐pyrroline‐5‐carboxylate. The basic biochemical parameters for ProDH and P5CDH activities were obtained for both in cell free extracts. The encoding genes were identified. H. halophilus has two isogenes each for prodh and p5cdh. prodh2 and p5cdh2 form an operon (put operon) whose mRNA is highly abundant in proline‐grown cells. Expression of the put operon was also upregulated by salinity and late growth phase in glucose‐grown cells. Similarly, ProDH and P5CDH activities increased in late exponential growth phase. This observation is in line with the previous notion that the compatible solute proline is degraded in stationary phase (in glucose grown cultures).
Hyperchloremic acidosis during plasma expansion
Authors: TAVERNIER BENOÎT , FAIVRE SÉBASTIEN , BOURDON CAROLINE
Published: October 2010

Many crystalloid and colloid plasma expanders can induce ‘hyperchloremic’ metabolic acidosis. This finding, first reported over 50 years ago, has received renewed interest following the recent availability of ‘balanced’ solutions. Several questions must be addressed and answered before making recommendations with regard to the use of these solutions. Do acidosis and hyperchloremia always go hand in hand? What is the clinical impact of hyperchloremic acidosis? Are all ‘balanced’ plasma expanders equivalent? Should isotonic saline‐based plasma expanders be abandoned? Several elements of reflection are summarized in this brief review. On the basis on the currently available literature, it is not objectively possible to propose clear‐cut guidelines.
Effect of Geometrical Assumptions on Numerical Modeling of Coronary Blood Flow Under Normal and Disease Conditions
Authors: Shanmugavelayudam Saravan Kumar , Rubenstein David A. , Yin Wei
Published: October 2010

Shear stress plays a pivotal role in pathogenesis of coronary heart disease. The spatial and temporal variation in hemodynamics of blood flow, especially shear stress, is dominated by the vessel geometry. The goal of the present study was to investigate the effect of 2D and 3D geometries on the numerical modeling of coronary blood flow and shear stress distribution. We developed physiologically realistic 2D and 3D models (with similar geometries) of the human left coronary artery under normal and stenosis conditions (30%, 60%, and 80%) using PROE (WF 3). Transient blood flows in these models were solved using laminar and turbulent (k-ω) models using a computational fluid dynamics solver, FLUENT (v6.3.26). As the stenosis severity increased, both models predicted a similar pattern of increased shear stress at the stenosis throat, and in recirculation zones formed downstream of the stenosis. The 2D model estimated a peak shear stress value of 0.91, 2.58, 5.21, and 10.09 Pa at the throat location under normal, 30%, 60%, and 80% stenosis severity. The peak shear stress values at the same location estimated by the 3D model were 1.41, 2.56, 3.15, and 13.31 Pa, respectively. The 2D model underestimated the shear stress distribution inside the recirculation zone compared with that of 3D model. The shear stress estimation between the models diverged as the stenosis severity increased. Hence, the 2D model could be sufficient for analyzing coronary blood flow under normal conditions, but under disease conditions (especially 80% stenosis) the 3D model was more suitable.
Finite Element Algorithm for Frictionless Contact of Porous Permeable
Media Under Finite Deformation and Sliding
Authors: Ateshian Gerard A. , Maas Steve , Weiss Jeffrey A.
Published: October 2010

This study formulates and implements a finite element contact algorithm for solid-fluid (biphasic) mixtures, accommodating both finite deformation and sliding. The finite element source code is made available to the general public. The algorithm uses a penalty method regularized with an augmented Lagrangian method to enforce the continuity of contact traction and normal component of fluid flux across the contact interface. The formulation addresses the need to automatically enforce free-draining conditions outside of the contact interface. The accuracy of the implementation is verified using contact problems, for which exact solutions are obtained by alternative analyses. Illustrations are also provided that demonstrate large deformations and sliding under configurations relevant to biomechanical applications such as articular contact. This study addresses an important computational need in the biomechanics of porous-permeable soft tissues. Placing the source code in the public domain provides a useful resource to the biomechanics community.
Interactions Between Flip Chip Underfill and Solder Alloy
Authors: Blass D. , Borgesen P.
Published: October 2010

The effects of underfill selection on flip chip reliability were always a complex issue. Mechanical optimization of the underfill performance, achieved by the addition of appropriate fillers, is invariably a tradeoff between the adhesion and the coefficient of thermal expansion (CTE) and, thus, also between in-plane and out-of-plane stresses. Another critical concern is the degradation of the underfill in processing and/or long term exposure to operating temperatures and ambient humidity. This is strongly affected by the chemical compatibility with combinations of solder mask, chip passivation, and flux residues. The latter is believed to be responsible for our observation of interactions with the solder alloy, too. As for the effects of glass transition temperatures and CTE, we find materials that were close to optimum for eutectic SnPb to be very far from the best options for lead free joints. We report on two sets of systematic experiments. The first addressed the performance of combinations of underfills, no-clean fluxes, and solder alloys in a JEDEC level 3 moisture sensitivity test. The second one involved thermal shock testing of flip chip assemblies underfilled with one of five different materials after soldering with SnCu, SAC305, and SnPb.
Reliability of High-Power Light Emitting Diode Attached With Different Thermal Interface Materials
Authors: Li Xin , Chen Xu , Lu Guo-Quan
Published: October 2010

As a solid electroluminescent source, white light emitting diode (LED) has entered a practical stage and become an alternative to replace incandescent and fluorescent light sources. However, due to the increasing integration and miniaturization of LED chips, heat flux inside the chip is also increasing, which puts the packaging into the position to meet higher requirements of heat dissipation. In this study, a new interconnection material—nanosilver paste is used for the LED chip packaging to pursue a better optical performance, since high thermal conductivity of this material can help improve the efficiency of heat dissipation for the LED chip. The bonding ability of this new die-attach material is evaluated by their bonding strength. Moreover, high-power LED modules connected with nanosilver paste, Sn3Ag0.5Cu solder, and silver epoxy are aged under hygrothermal aging and temperature cycling tests. The performances of these LED modules are tested at different aging time. The results show that LED modules sintered with nanosilver paste have the best performance and stability.
Comparative study on the nonperiodic and periodic gratings for scanning probe microscopy drift measurements
Authors: Niu Dun , Li Jiawen , Chen Yuhang , Huang Wenhao
Published: October 2010

Performances of a special nonperiodic grating (NPG) and a conventional periodic grating (PG) for scanning probe microscopy (SPM) drift measurements are compared. Experimental results verify that the NPG has the advantages of robust measurements and large measurable range. The correlation peak contrast of the SPM image of the fabricated NPG reaches 17.8, which enables enough stable drift measurement by correlation analysis of sequentially scanned images. The measurable drift range relies on the grating size of the NPG, while it is limited by the grating pitch of the PG. For SPM drift characterization, the NPG prevails against the ordinary PG since both the peak contrast and the measurable range can be easily improved by more than one order of magnitude.
Fossil Evidence for Evolution of the Shape and Color of Penguin Feathers
Authors: Clarke Julia A. , Ksepka Daniel T. , Salas-Gismondi Rodolfo , Altamirano Ali J. , Shawkey Matthew D. , D’Alba Liliana , Vinther Jakob , DeVries Thomas J. , Baby Patrice
Published: October 2010

Feather of the Penguin

Penguins are highly adapted for their cold, aquatic environment. Changes in their wings and feathers have allowed rapid swimming and protection from the near-freezing water.

Clarke
et al.

(p.
954
, published online 30 September; see the cover) describe an early penguin, dating to about 35 million years ago, that includes well-preserved feathers. The melanosomes in the feathers, which influence their strength, as well as their color, are like those of many other aquatic birds and unlike those of present-day penguins, even though the morphology of the wings and feathers had already been modified. Thus, in penguins, the shape and form of the feather evolved before microstructural changes occurred. The melanosome arrangement also suggests that the penguin was mostly gray-brown.
Structure of a Eukaryotic CLC Transporter Defines an Intermediate State in the Transport Cycle
Authors: Feng Liang , Campbell Ernest B. , Hsiung Yichun , MacKinnon Roderick
Published: October 2010

Controlling Chloride Channels

The CLC proteins are a large family of channels and transporters that transfer chloride ions across cell membranes. While structures of two prokaryotic CLCs have been determined, these do not include the cytoplasmic regulatory domains found in eukaryotic transporters, and the structures do not reveal the mechanism of Cl
−
/H
+
–coupled transport.

L. Feng
et al.

(p.
635
, published online 30 September; see the Perspective by

Mindell

) describe the structure of a eukaryotic CLC protein and found that the regulatory domains interacted closely with the transmembrane domain so that conformational changes are transmitted to the ion pathway. A gating glutamate in the eukaryote transporter is in a different conformation to prokaryotic structures, explaining the 2:1 stoichiometry of Cl
−
/H
+
exchange in eukaryotes.
REVIEW OF LINAC–RING-TYPE COLLIDER PROPOSALS
Authors: AKAY A. N. , KARADENIZ H. , SULTANSOY S.
Published: October 2010

There are three possible types of particle colliders schemes: familiar (well-known) ring–ring colliders, less familiar but sufficiently advanced linear colliders, and less familiar and less advanced linac–ring-type colliders. The aim of this paper is twofold: to present a possibly complete list of papers on linac–ring-type collider proposals and to emphasize the role of linac–ring-type machines for future HEP research.
TRANSPORT IN JOSEPHSON JUNCTION WITH TIME DELAY AND COUPLING BETWEEN NOISE TERMS
Authors: WU DAN , ZHU SHIQUN
Published: October 2010

The transport of a spatially periodic system with time delayed feedback driven by coupled noise terms is investigated. A general approximate equation of the current is derived. For the superconduction Josephson junction, it is found that suitable time delay can enhance the current in the system. In the presence of the coupling between noise terms, the current direction is determined by the sign of the coupling. The negative coupling can induce positive current, while the positive coupling can induce negative current. The absolute value of the current is a peaked function of the additive noise but a monotonically increasing function of the multiplicative noise. Numerical simulations are in good agreement with the approximate theoretical results.
OPTICAL AND ELECTRONIC PROPERTIES OF M2Si (M = Mg, Ca, Sr) GROWN BY REACTIVE DEPOSITION TECHNIQUE
Authors: HU JUNHUA , KATO AKIHIKO , SADOH TAIZOH , MAEDA YOSHUHITO , GALKIN K. N. , TURCHIN T. V. , TATSUOKA HIROKAZU
Published: October 2010

Single phase M 2 Si ( M = Mg , Ca , Sr ) silicides were grown using Si substrates, by thermal treatment of the substrates in the vapors of the metallic sources, M , and the electronic structures and optical property of the silicides were investigated. The electronic band structures of the silicides were calculated using the first-principles total-energy calculation program in pseudopotential schemes with plane-wave basis functions. The calculated optical reflectance spectra were also deduced from the theoretical band structures, and roughly agreed with the experimental results except for the low reflectance intensity around 2 eV. This suggests that the energy band gap of the silicides roughly agree with the calculated values of 0.15, 0.31 and 0.35 eV for Mg 2 Si , Ca 2 Si and Sr 2 Si , respectively, within the underestimation of the band gap by the density functional calculation. The optical property of the silicides is also discussed in relation to the morphological structures of the silicides.
CALCULATION OF VOLUME AS FUNCTIONS OF TEMPERATURE AND PRESSURE IN ICE I CLOSE TO THE MELTING POINT
Authors: KILIT E. , YURTSEVEN H.
Published: October 2010

We calculate in this study the volume of ice I as functions of temperature and pressure close to the melting point by analyzing the experimental data for the thermal expansivity. Using an approximate relation, the temperature dependence of the volume is calculated at 202.4 MPa from the thermal expansivity of ice I. The pressure dependence of the volume is also calculated at 252.3 K from the isothermal compressibility of ice I close to the melting point.

The volume calculated here as functions of temperature and pressure shows critical behavior close to the melting point in ice I, which can be tested by the experimental measurements.
THE ROLE OF INTERNAL NOISE FOR OPTIMAL INTRACELLULAR CALCIUM SIGNALING IN COUPLED BIOLOGICAL CELL SYSTEM
Authors: LI HONGYING , BI JIANHONG
Published: October 2010

We have studied the role of internal noise for intracellular calcium signaling in coupled biological cell system. It is found that internal noise can induce calcium oscillations and the performance of such oscillations shows two peaks with the variation of the cell size-Ω for any cell chain length-N, indicating the occurrence of system size bi-resonance or internal noise stochastic bi-resonance, which may be very relevant to the canard explosion. We also find that there exists an optimal cell chain length-N for the first peak at which the collective calcium oscillations show the best performance, it is also a phenomenon of "system size resonance". It is interesting to note that one of the optimal cell sizes is present at Ω ~ 103μm3, which is close to a real living cell size in vivo.
RCRT
Authors: Paek Jeongyeup , Govindan Ramesh
Published: October 2010

Emerging high-rate applications (imaging, structural monitoring, acoustic localization) will need to transport large volumes of data concurrently from several sensors. These applications are also loss-intolerant. A key requirement for such applications, then, is a protocol that reliably transports sensor data from many sources to one or more sinks without incurring congestion collapse. In this article, we discuss RCRT, a rate-controlled reliable transport protocol suitable for constrained sensor nodes. RCRT uses end-to-end explicit loss recovery, but places all the congestion detection and rate adaptation functionality in the sinks. This has two important advantages: efficiency and flexibility. Because sinks make rate allocation decisions, they are able to achieve greater efficiency since they have a more comprehensive view of network behavior. For the same reason, it is possible to alter the rate allocation decisions (for example, from one that ensures that all nodes get the same rate, to one that ensures that nodes get rates in proportion to their demands), without modifying sensor code at all. We evaluate RCRT extensively on a 40-node wireless sensor network testbed and show that RCRT achieves 1.7 times the rate achieved by IFRC and 1.4 times that of WRCP, two recently proposed interference-aware distributed rate-control protocols. We also present results from a 3-month-long 19-node real world deployment of RCRT in an imaging application and show that RCRT works well in real long-term deployments.
On the interaction of clocks, power, and synchronization in duty-cycled embedded sensor nodes
Authors: Schmid Thomas , Shea Roy , Charbiwala Zainul , Friedman Jonathan , Srivastava Mani B. , Cho Young H.
Published: October 2010

The efficiency of the time synchronization service in wireless sensor networks is tightly connected to the design of the radio, the quality of the clocking hardware, and the synchronization algorithm employed. While improvements can be made on all levels of the system, over the last few years most work has focused on the algorithmic level to minimize message exchange and in radio architectures to provide accurate time-stamping mechanisms. Surprisingly, the influences of the underlying clock system and its impact on the overall synchronization accuracy has largely been unstudied.

In this work, we investigate the impact of the clocking subsystem on the time synchronization service and address, in particular, the influence of changes in environmental temperature on clock drift in highly duty-cycled wireless sensor nodes. We also develop formulas that help the system architect choose the optimal resynchronization period to achieve a given synchronization accuracy. We find that the synchronization accuracy has a two region behavior. In the first region, the synchronization accuracy is limited by quantization error, while int he second region changes in environmental temperature impact the achievable accuracy. We verify our analytic results in simulation and real hardware experiments.
Should code be released?
Authors: McCafferty Dennis
Published: October 2010

Software code can provide important insights into the results of research, but it's up to individual scientists whether their code is released---and many opt not to.
Nonparametric belief propagation
Authors: Sudderth Erik B. , Ihler Alexander T. , Isard Michael , Freeman William T. , Willsky Alan S.
Published: October 2010

Continuous quantities are ubiquitous in models of real-world phenomena, but are surprisingly difficult to reason about automatically. Probabilistic graphical models such as Bayesian networks and Markov random fields, and algorithms for approximate inference such as belief propagation (BP), have proven to be powerful tools in a wide range of applications in statistics and artificial intelligence. However, applying these methods to models with continuous variables remains a challenging task. In this work we describe an extension of BP to continuous variable models, generalizing particle filtering, and Gaussian mixture filtering techniques for time series to more complex models. We illustrate the power of the resulting nonparametric BP algorithm via two applications: kinematic tracking of visual motion and distributed localization in sensor networks.
Cheating in Computer Science
Authors: Murray William Hugh
Published: October 2010

Many computer science teachers are very concerned about students cheating in their courses. Surveys report that almost three-quarters of high school students admit to cheating within the past year. John Barrie, founder of the plagiarism-detecting Web site Turnitin.com, says that about a third of the papers submitted to the site have significant levels of plagiarism. Many people say that the Internet has made cheating easier and harder to detect and they wonder if the moral fabric of our youth is fraying. In the trenchant analysis below, Bill Murray approaches the teaching-learning system as a game in which students, teachers, and others play various roles. He wonders whether the game itself encourages cheating, and suggests that teachers could restructure the game so that cheating is less rewarding and less likely.
--Peter J. Denning