bluuebunny/crossref_metadata_2025 huggingface dataset:
A CONFORMING POINT INTERPOLATION METHOD (CPIM) BY SHAPE FUNCTION RECONSTRUCTION FOR ELASTICITY PROBLEMS
Authors: XU X. , LIU G. R. , GU Y. T. , ZHANG G. Y.
Published: November 2010

A conforming point interpolation method (CPIM) is proposed based on the Galerkin formulation for 2D mechanics problems using triangular background cells. A technique for reconstructing the PIM shape functions is proposed to create a continuous displacement field over the whole problem domain, which guarantees the CPIM passing the standard patch test. We prove theoretically the existence and uniqueness of the CPIM solution, and conduct detailed analyses on the convergence rate; computational efficiency and band width of the stiffness matrix of CPIM. The CPIM does not introduce any additional degrees of freedoms compared to the linear FEM and original PIM; while convergence rate of quadratic CPIM is in between that of linear FEM and quadratic FEM which results in the high computational efficiency. Intensive numerical studies verify the properties of the CPIM.
MEDIAPOD: A POCKET-SIZED AND PERSONALIZED MULTIMEDIA DESKTOP
Authors: POTTER SHAYA , LAADAN OREN , BARATTO RICARDO , KIM LEONARD , NIEH JASON
Published: November 2010

We present MediaPod, a portable system that allows mobile users to maintain the same persistent, personalized multimedia desktop environment on any available computer. Regardless of which computer is being used, MediaPod provides a consistent multimedia desktop session, maintaining all of a user's applications, documents and configuration settings. This is achieved by leveraging rapid improvements in capacity, cost, and size of portable storage devices. MediaPod provides a virtualization and checkpoint-restart mechanism that decouples a desktop environment and its applications from the host, enabling multimedia desktop sessions to be suspended to portable storage, carried around, and resumed from the storage device on another computer. MediaPod virtualization also isolates desktop sessions from the host, protecting the privacy of the user and preventing malicious applications from damaging the host. We have implemented a Linux MediaPod prototype and demonstrate its ability to quickly suspend and resume multimedia desktop sessions, enabling a seamless computing experience for mobile users as they move among computers.
Constant Final Yield
Authors: Weiner Jacob , Freckleton Robert P.
Published: November 2010

Constant final yield is an empirical generalization concerning the total biomass production of plant stands growing at different densities after a period of growth. Total standing biomass initially increases in proportion to density, levels off, and then remains constant as density increases further. We review the empirical basis for and mathematical formulations of this pattern, and we clarify the relationship of constant final yield to density-dependent mortality (self-thinning). There are several mechanisms that can explain the pattern, and it has a clear evolutionary basis. Constant final yield is a key to understanding population- and community-level phenomena. Establishing whether or not a plant community is at or close to constant final yield is important for understanding and predicting its behavior. It represents the maximum biomass for a genotype in an environment after a period of growth and, as such, can serve as a baseline for the measurement of disturbance in plant communities.
Ecosystem Consequences of Biological Invasions
Authors: Ehrenfeld Joan G.
Published: November 2010

Exotic species affect the biogeochemical pools and fluxes of materials and energy, thereby altering the fundamental structure and function of their ecosystems. Rapidly accumulating evidence from many species of both animal and plant invaders suggests that invasive species often increase pool sizes, particularly of biomass, and promote accelerated flux rates, but many exceptions can be found. Ecosystem dynamics are altered through a variety of interacting, mutually reinforcing mechanistic pathways, including species' resource acquisition traits; population densities; ability to engineer changes to physical environmental conditions; effects on disturbance, especially fire; regimes; the ability to structure habitat for other species; and their impact on food webs. Local factors of landscape setting, history, and other sources of disturbance constrain ecosystem responses to invasions. New research directions are suggested, including the need for whole-system budgets, the quantification of abundance-impact relationships for particular ecosystem processes, and a better exploration of food web impacts on ecosystem processes.
The Ecological Impact of Biofuels
Authors: Fargione Joseph E. , Plevin Richard J. , Hill Jason D.
Published: November 2010

The ecological impact of biofuels is mediated through their effects on land, air, and water. In 2008, about 33.3 million ha were used to produce food-based biofuels and their coproducts. Biofuel production from food crops is expected to increase 170% by 2020. Economic model estimates for land-use change (LUC) associated with food-based biofuels are 67–365 ha 10−6 l−1, leading to increased greenhouse gas emissions for decades compared to business as usual. Biodiversity is reduced by about 60% in U.S. corn and soybean fields and by about 85% in Southeast Asian oil palm plantations compared to unconverted habitat. Consequently, the largest ecological impact of biofuel production may well come from market-mediated LUC. Mitigating this impact requires targeting biofuel production to degraded and abandoned cropland and rangeland; increasing crop yields and livestock production efficiency; use of wastes, residues, and wildlife-friendly crops; and compensatory offsite mitigation for residual direct and indirect impacts.
The Ecological and Evolutionary Consequences of Clonality for Plant Mating
Authors: Vallejo-Marín Mario , Dorken Marcel E. , Barrett Spencer C.H.
Published: November 2010

Many flowering plants exhibit dual reproductive modes, producing both sexual and asexual offspring. The commonest form of asexual reproduction is clonal growth, in which vegetative modules (ramets) are produced by the parental genotype (genet). In plants, sexual and asexual reproduction usually occur simultaneously, and this can lead to allocation trade-offs and antagonism between reproductive modes. Our review considers the ecological and evolutionary consequences of functional interactions between clonal reproduction and pollination and mating. Clonal reproduction is commonly associated with mass flowering, restricted pollen dispersal, and geitonogamous self-pollination, processes that can result in inbreeding depression and pollen discounting. We review evidence for the correlated evolution of clonality and sexual systems, particularly self-incompatibility, and identify several floral mechanisms that function to reduce mating costs by limiting selfing and pollen discounting. We conclude by discussing the loss of sexuality in clonal plants and consider the genetic and environmental basis of sexual dysfunction.
Nectar Robbing: Ecological and Evolutionary Perspectives
Authors: Irwin Rebecca E. , Bronstein Judith L. , Manson Jessamyn S. , Richardson Leif
Published: November 2010

Not all floral visitors attracted to flowers are pollinators. Instead, some visitors circumvent the floral opening, usually removing nectar without contacting the anthers and/or stigma. Here we review the evolutionary ecology of nectar robbing from both the plant and animal perspective. Effects of robbing on female and male components of plant reproduction range from negative to positive. Their underlying mechanisms are diverse, including direct effects and indirect effects mediated through changes in pollination. We detail how plants may be able to deter robbers through morphological and chemical traits. For the evolutionary ecology of robbing to move beyond a phytocentric perspective, studies must also address the causes of robbing and the consequences for both robbers and pollinators. We use an energetics approach to evaluate these causes and consequences. Finally, we highlight unanswered questions in need of further research.
Phylogenetic Insights on Adaptive Radiation
Authors: Glor Richard E.
Published: November 2010

Adaptive radiation is a response to natural selection and ecological opportunity involving diversification of species and associated adaptations. Although evolutionary biologists have long speculated that adaptive radiation is responsible for most of life's diversity, persistent confusion and disagreement over some of its most fundamental questions have prevented it from assuming a central role in explaining the evolution of biological diversity. Today, answers to many of these questions are emerging from a new wave of integrative research that combines phylogenetic trees with a variety of other data and perspectives. In this review, I discuss how modern phylogenetic analyses are central to (a) defining and diagnosing adaptive radiation, (b)identifying the factors underlying the occurrence and scope of adaptive radiation, (c)diagnosing predictable patterns of ecological diversification during adaptive radiation, and (d) reconstructing the history of adaptive radiations.
Relationships between hepatic stearoyl-CoA desaturase-1 activity and mRNA expression with liver fat content in humans
Authors: Peter Andreas , Cegan Alexander , Wagner Silvia , Elcnerova Michaela , Königsrainer Alfred , Königsrainer Ingmar , Häring Hans-Ulrich , Schleicher Erwin D. , Stefan Norbert
Published: November 2010

Stearoyl-CoA desaturase-1 (SCD1) has gained much interest as a future drug target to treat fatty liver and its consequences. However, there are few and inconsistent human data about expression and activity of this important enzyme. We investigated activity and expression of SCD1 and their relationships with liver fat (LF) content in human liver samples. Fifty subjects undergoing liver surgery were studied. SCD1 activity was estimated from the ratio of oleate (C18:1) to stearate (C18:0) within lipid subfractions. Furthermore, SCD1 mRNA expression and LF content were measured. Similarly to previous studies, we observed a strong positive correlation between LF content and the C18:1/C18:0 ratio in the combined fatty acid (FA) fractions ( r = 0.96, P < 0.0001), which could be interpreted as higher SCD1 activity with increasing LF. However, hepatic SCD1 mRNA expression did not correlate with LF ( r = 0.16, P = 0.13). To solve these conflicting data, we analyzed the FA composition of hepatic lipid subfractions. With increasing LF content the amount of FAs from the triglyceride (TG) fraction increased ( r = 0.96, P < 0.0001), whereas the FAs from the phospholipid (PL) fraction remained unchanged ( r = −0.17, P = 0.19). Of these two major lipid fractions, the C18:1/C18:0 ratio in TG was 16-fold higher than in PL. Supporting the SCD1 mRNA expression data, the C18:1/C18:0 ratio of the TG or PL fraction did not correlate with LF ( r = 0.26, P = 0.12 and r = 0.08, P = 0.29). We provide novel information that SCD1 activity and mRNA expression appear not to be elevated in subjects with high LF content. We suggest that the FA composition of lipid subclasses, rather than of mixed lipids, should be analyzed to estimate SCD1 activity.
Vascular smooth muscle cell glycocalyx modulates shear-induced proliferation, migration, and NO production responses
Authors: Kang Hongyan , Fan Yubo , Deng Xiaoyan
Published: October 2010

The endothelial cell glycocalyx, a structure coating the luminal surface of the vascular endothelium, and its related mechanotransduction have been studied by many over the last decade. However, the role of vascular smooth muscle cells (SMCs) glycocalyx in cell mechanotransduction has triggered little attention. This study addressed the role of heparan sulfate proteoglycans (HSPGs), a major component of the glycocalyx, in the shear-induced proliferation, migration, and nitric oxide (NO) production of the rat aortic smooth muscle cells (RASMCs). A parallel plate flow chamber and a peristaltic pump were employed to expose RASMC monolayers to a physiological level of shear stress (12 dyn/cm2). Heparinase III (Hep.III) was applied to selectively degrade heparan sulfate on the SMC surface. Cell proliferation, migration, and NO production rates were determined and compared among the following four groups of cells: 1) untreated with no flow, 2) Hep.III treatment with no flow, 3) untreated with flow of 12 dyn/cm2exposure, and 4) Hep.III treatment with flow of 12 dyn/cm2exposure. It was observed that flow-induced shear stress significantly suppressed SMC proliferation and migration, whereas cells preferred to aligning along the direction of flow and NO production were enhanced substantially. However, those responses were not found in the cells with Hep.III treatment. Under flow condition, the heparinase III-treated cells remained randomly oriented and proliferated as if there were no flow presence. Disruption of HSPG also enhanced wound closure and inhibited shear-induced NO production significantly. This study suggests that HSPG may play a pivotal role in mechanotransduction of SMCs.
Linear Versus Nonlinear Signal Transmission in Neuron Models With Adaptation Currents or Dynamic Thresholds
Authors: Benda Jan , Maler Leonard , Longtin André
Published: November 2010

Spike-frequency adaptation is a prominent aspect of neuronal dynamics that shapes a neuron's signal processing properties on timescales ranging from about 10 ms to >1 s. For integrate-and-fire model neurons spike-frequency adaptation is incorporated either as an adaptation current or as a dynamic firing threshold. Whether a physiologically observed adaptation mechanism should be modeled as an adaptation current or a dynamic threshold, however, is not known. Here we show that a dynamic threshold has a divisive effect on the onset f–I curve (the initial maximal firing rate following a step increase in an input current) measured at increasing mean threshold levels, i.e., adaptation states. In contrast, an adaptation current subtractively shifts this f–I curve to higher inputs without affecting its slope. As a consequence, an adaptation current acts essentially linearly, resulting in a high-pass filter component of the neuron's transfer function for current stimuli. With a dynamic threshold, however, the transfer function strongly depends on the input range because of the multiplicative effect on the f–I curves. Simulations of conductance-based spiking models with adaptation currents, such as afterhyperpolarization (AHP)-type, M-type, and sodium-activated potassium currents, do not show the divisive effects of a dynamic threshold, but agree with the properties of integrate-and-fire neurons with adaptation current. Notably, the effects of slow inactivation of sodium currents cannot be reproduced by either model. Our results suggest that, when lateral shifts of the onset f–I curve are seen in response to adapting inputs, adaptation should be modeled with adaptation currents and not with a dynamic threshold. In contrast, when the slope of onset f–I curves depends on the adaptation state, then adaptation should be modeled with a dynamic threshold. Further, the observation of divisively altered onset f–I curves in adapted neurons with notable variability of their spike threshold could hint to yet known biophysical mechanisms directly affecting the threshold.
Spectral Responses in Zebrafish Horizontal Cells Include a Tetraphasic Response and a Novel UV-Dominated Triphasic Response
Authors: Connaughton Victoria P. , Nelson Ralph
Published: November 2010

Zebrafish are tetrachromats with red (R, 570 nm), green (G, 480 nm), blue (B, 415 nm), and UV (U, 362 nm) cones. Although neurons in other cyprinid retinas are rich in color processing neural circuitry, spectral responses of individual neurons in zebrafish retina, a genetic model for vertebrate color vision, are yet to be studied. Using dye-filled sharp microelectrodes, horizontal cell voltage responses to light stimuli of different wavelengths and irradiances were recorded in a superfused eyecup. Spectral properties were assessed both qualitatively and quantitatively. Six spectral classes of horizontal cell were distinguished. Two monophasic response types (L1 and L2) hyperpolarized at all wavelengths. L1 sensitivities peaked at 493 nm, near the G cone absorbance maximum. Modeled spectra suggest equally weighted inputs from both R and G cones and, in addition, a “hidden opponency” from blue cones. These were classified as R−/G−/(b+). L2 sensitivities were maximal at 563 nm near the R cone absorbance peak; modeled spectra were dominated by R cones, with lesser G cone contributions. B and UV cone signals were small or absent. These are R−/g−. Four chromatic (C-type) horizontal cells were either depolarized (+) or hyperpolarized (−) depending on stimulus wavelength. These types are biphasic (R+/G−/B−) with peak excitation at 467 nm, between G and B cone absorbance peaks, UV triphasic (r−/G+/U−) with peak excitation at 362 nm similar to UV cones, and blue triphasic (r−/G+/B−/u−) and blue tetraphasic (r−/G+/B−/u+), with peak excitation at 409 and 411 nm, respectively, similar to B cones. UV triphasic and blue tetraphasic horizontal cell spectral responses are unique and were not anticipated in previous models of distal color circuitry in cyprinids.
Positive Solutions of a Singular Positone and Semipositone Boundary Value Problems for Fourth‐Order Difference Equations
Authors: Yuan Chengjun
Published: November 2010

This paper studies the boundary value problems for the fourth‐order nonlinear singular difference equations Δ4u(i − 2) = λα(i)f(i, u(i)), i ∈ [2, T + 2], u(0) = u(1) = 0, u(T + 3) = u(T + 4) = 0. We show the existence of positive solutions for positone and semipositone type. The nonlinear term may be singular. Two examples are also given to illustrate the main results. The arguments are based upon fixed point theorems in a cone.
A Note on Periodic Solutions of Second Order Nonautonomous Singular Coupled Systems
Authors: Cao Zhongwei , Yuan Chengjun , Jiang Daqing , Wang Xiaowei
Published: November 2010

We establish the existence of periodic solutions
of the second order nonautonomous singular coupled systems x′′ + a1(t)x = f1(t, y(t)) + e1(t) for a.e. t ∈ [0, T], y′′ + a2(t)y = f2(t, x(t)) + e2(t) for a.e. t ∈ [0, T]. The proof relies on Schauder′s fixed point theorem.
The Possible Role of Epigenetics in Gestational Diabetes: Cause, Consequence, or Both
Authors: Fernández-Morera J. L. , Rodríguez-Rodero S. , Menéndez-Torre E. , Fraga M. F.
Published: October 2010

Gestational diabetes mellitus (GDM) is defined as the glucose intolerance that is not present or recognized prior to pregnancy. Several risk factors of GDM depend on environmental factors that are thought to regulate the genome through epigenetic mechanisms. Thus, epigenetic regulation could be involved in the development of GDM. In addition, the adverse intrauterine environment in patients with GDM could also have a negative impact on the establishment of the epigenomes of the offspring.
Analysis of Crack Propagation Path on the Anisotropic Bi‐Material Rock
Authors: Chen Chao-Shi , Tu Chia-Huei , Yang Chen-Cheng
Published: November 2010

This paper presents a single‐domain boundary element method (SDBEM) for linear elastic fracture mechanics analysis in the 2D anisotropic bimaterial. In this formulation, the displacement integral equation is collocated on the uncracked boundary only, and the traction integral equation is collocated on one side of the crack surface only. The complete fundamental solution (Green′s function) for anisotropic bi‐materials was also derived and implemented into the boundary integral formulation so the discretization along the interface can be avoided except for the interfacial crack part. A special crack‐tip element was introduced to capture exactly the crack‐tip behavior. A computer program with the FORTRAN code has been developed to effectively calculate the stress intensity factors, crack initiation angle, and propagation path of an anisotropic bi‐material. This SDBEM program has been verified having a good accuracy with the previous researches. In addition, a rock of type (1)/(2) disk specimen with a central crack was made to conduct the Brazilian test under diametrical loading. The result shows that the numerical analysis can predict relatively well the direction of crack initiation and the path of crack propagation.
Resveratrol: Challenges in Translation to the Clinic — A Critical Discussion
Authors: Subramanian Lalita , Youssef Sherry , Bhattacharya Saswati , Kenealey Jason , Polans Arthur S. , van Ginkel Paul R.
Published: November 2010

Low cancer survival rates and the serious side effects often associated with current chemotherapeutics highlight the need for new and effective nontoxic anticancer agents. Since 1997 when Jang and colleagues first described resveratrol's ability to inhibit carcinogenesis, it has consistently proven effective at tumor inhibition in diverse human cancer models. This finding has raised the hope that resveratrol would pioneer a novel class of nontoxic chemotherapeutics. As a consequence of initial basic and preclinical studies, resveratrol is now being extensively promoted in the unregulated nutraceutical sector. However, some fundamental aspects of resveratrol's action need to be understood before it can be developed into a clinically viable anticancer drug. These areas pertain to the key mechanism(s) by which resveratrol potentiates its antitumor effects. Current research suggests that these mechanisms might be through novel pathways, requiring an understanding of cellular uptake, sentinel targets, and in vivo biological networks. The metabolism of resveratrol and its bioavailablity also warrant further consideration in light of recent in vitro and in vivo studies. Finally, we need to appreciate the sorts of information about resveratrol that may translate between different disease entities. We present a critical discussion of these issues and suggest important experiments that could pave the way to the successful translation of resveratrol to the clinic.Clin Cancer Res; 16(24); 5942–8. ©2010 AACR.
MS-275 Sensitizes TRAIL-Resistant Breast Cancer Cells, Inhibits Angiogenesis and Metastasis, and Reverses Epithelial-Mesenchymal Transition In vivo
Authors: Srivastava Rakesh K. , Kurzrock Razelle , Shankar Sharmila
Published: November 2010

Histone deacetylase (HDAC) inhibitors and tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) show promise for the treatment of cancers. The purpose of this study was to examine the molecular mechanisms by which HDAC inhibitor MS-275 sensitizes TRAIL-resistant breast cancer cells in vivo, inhibits angiogenesis and metastasis, and reverses epithelial-mesenchymal transition (EMT). BALB/c nude mice were orthotopically implanted with TRAIL-resistant invasive breast cancer MDA-MB-468 cells and treated intravenously with MS-275, TRAIL, or MS-275 followed by TRAIL, 4 times during first 3 weeks. Treatment of mice with TRAIL alone had no effect on tumor growth, metastasis, angiogenesis, and EMT. In comparison, MS-275 sensitized TRAIL-resistant xenografts by inducing apoptosis, inhibiting tumor cell proliferation, angiogenesis, metastasis, and reversing EMT. Treatment of nude mice with MS-275 resulted in downregulation of NF-κB and its gene products (cyclin D1, Bcl-2, Bcl-XL, VEGF, HIF-1α, IL-6, IL-8, MMP-2, and MMP-9) and upregulation of DR4, DR5, Bax, Bak, and p21/CIP1 in tumor cells. Furthermore, MS-275-treated mice showed significantly reduced tumor growth and decreased circulating vascular VEGFR2-positive endothelial cells, CD31-positive or von Willebrand factor–positive blood vessels, and lung metastasis compared with control mice. Interestingly, MS-275 caused “cadherin switch” and reversed EMT as shown by the upregulation of E-cadherin and downregulation of N-cadherin and transcription factors Snail, Slug, and ZEB1. In conclusion, sequential treatments of mice with MS-275 followed by TRAIL may target multiple pathways to reverse EMT and inhibit tumor progression, angiogenesis, and metastasis and represent a novel therapeutic approach to treat cancer. Mol Cancer Ther; 9(12); 3254–66. ©2010 AACR.
Low Bone Mineral Density and High Incidences of Fractures and Vitamin D Deficiency in 52 Pediatric Cancer Survivors
Authors: Bilariki Kalliopi , Anagnostou Elli , Masse Virginie , Elie Caroline , Grill Jacques , Valteau-Couanet Dominique , Kalifa Chantal , Doz François , Sainte-Rose Christian , Zerah Michel , Mascard Eric , Mosser Françoise , Ruiz Jean-Charles , Souberbielle Jean-Claude , Eladari Dominique , Brugières Laurence , Polak Michel
Published: November 2010

Objective: To evaluate bone mineral density (BMD), fractures, and vitamin D deficiency in pediatric patients in complete remission of solid tumor; and to identify risk factors for these three abnormalities. Study Design: Data were collected prospectively after completion of cancer treatment. Hormonal and vitamin D deficiencies were treated. The patients were evaluated again 1 year later. Patients: 52 consecutive patients, 30 boys and 22 girls. Among them, 21 completed the second evaluation. Measurements: A clinical examination, nutritional assessment, and laboratory workup were performed. BMD was measured by absorptiometry. Results: Calcium intake was inadequate in 75% of patients and vitamin D reserves were low in 61.5%. BMD was low at the spine in 32.7%, and at the femur in 24% of patients. Spinal and femoral BMD Z-scores correlated significantly with each other. Femoral BMD Z-score showed significant positive correlations with changes in body mass index, urinary calcium/creatinine ratio, and time since treatment completion, and a significant negative correlation with treatment duration. Fractures were noted in 10 patients but were not correlated with BMD. In the 21 re-evaluated patients, no significant improvements were found in calcium intake, vitamin D status, or BMD Z-score. Conclusions: Survivors of childhood solid cancer have high rates of insufficient calcium intake, vitamin D deficiency, low bone mass and fractures.
Should Blood Gas Analysis Be Part of the Diagnostic Workup of Short Children? Auxological Data and Blood Gas Analysis in Children with Renal Tubular Acidosis
Authors: Mul D. , Grote F.K. , Goudriaan J.R. , de Muinck Keizer-Schrama S.M.P.F. , Wit J.M. , Oostdijk W.
Published: November 2010

Background: Renal tubular acidosis (RTA) is a rare cause of growth failure, therefore it is uncertain whether routine screening with blood gas analysis of short infants and children is cost-effective. Objective: To investigate the clinical, growth and laboratory parameters in children with RTA to estimate the possible value of laboratory screening for this disorder in infants and children referred for short stature according to a recent guideline. Method: Retrospective chart analysis of 30 children diagnosed between 1978 and 2005 in The Netherlands and 3 centers in Belgium. Results: The current guideline for short stature detected 33% of children with RTA. Assuming a pre-test probability of RTA of 0.6 per 100,000 births, the likelihood ratio of poor growth was 58 and 17 below and above 3 years, respectively. Sensitivity was 17/30 and 12/24 for a –2.0 SDS cutoff for weight and body mass index, respectively. In infants and toddlers diagnosed before 3 years of age, the mean weight loss was 1.5 SD, and 0.8 SDS in older children. In short children >3 years RTA was extremely rare, always associated with clinical symptoms, and rarely detected by blood gas analysis. Conclusion: According to our data a decreasing weight SDS for age is a sufficient indication to perform blood gas analysis in children <3 years of age, particularly in the presence of additional clinical features, whereas it can be omitted in short children >3 years of age.
Normal-Weight 14-Year-Old Girl with Acanthosis Nigricans and Markedly Increased Hepatic Steatosis: Evidence for the Important Role of Ectopic Fat Deposition in the Pathogenesis of Insulin Resistance in Childhood and Adolescence
Authors: Springer Fabian , Nguyen Huu Phuc , Machann Jürgen , Schweizer Roland , Ranke Michael B. , Binder Gerhard , Schick Fritz , Ehehalt Stefan ,   for the DISKUS Study Group
Published: November 2010

Background: A major factor in the development of insulin resistance is obesity. While the contribution of intrahepatic lipids to insulin resistance is well established in adults, there are only few reports in childhood and adolescence. Aim: To investigate the correlation between ectopic fat deposition and insulin sensitivity in a normal-weight girl with acanthosis nigricans before and after lifestyle intervention. Methods: Variations in body fat composition and intrahepatic lipids were monitored by means of anthropometric measures and by means of methods based on magnetic resonance imaging and magnetic resonance spectroscopy. Results: We present the case of a normal-weight 14-year-old Caucasian girl with pronounced hepatic steatosis together with acanthosis nigricans, increased waist-circumference and increased visceral fat. During a 7-month period of lifestyle intervention, the girl lost 7.1 kg in weight. Acanthosis nigricans, whole-body insulin sensitivity index (WBISI) and homeostasis model assessment (HOMA) improved significantly (before intervention: WBISI 0.42, HOMA 22.2; after intervention: WBISI 1.35, HOMA 6.9). Even though all lipid compartments were decreased in size, the intrahepatic lipids showed an extraordinarily great reduction. Conclusion: This case presentation of a normal-weight girl with acanthosis nigricans and markedly increased hepatic steatosis provides support for the association between intrahepatic fat deposition and insulin resistance in adolescence.
Serum Adipocytokine and Vascular Inflammation Marker Levels in Beta-Thalassaemia Major Patients
Authors: Chaliasos Nikolaos , Challa Anna , Hatzimichael Eleftheria , Koutsouka Freideriki , Bourantas Dimitrios K. , Vlahos Antonios P. , Siamopoulou Antigone , Bourantas Konstantinos L. , Makis Alexandros
Published: November 2010

Background/Aim: The adipocytokines leptin and adiponectin represent a critical link between metabolism, immunity and chronic inflammation. A chronic vascular inflammatory state plays an important role in the pathophysiology of thalassaemia. We aimed to analyze the levels of these adipocytokines and determine any possible correlations with disease severity or vascular inflammation markers in beta-thalassaemia. Methods: Serum leptin, adiponectin, high-sensitivity C-reactive protein, endothelins, vascular adhesion molecule-1, intracellular adhesion molecule-1 and L- and E-selectin were measured in 28 beta-thalassaemia patients and compared with levels in healthy controls. Results: Leptin was significantly lower in patients compared to controls (2.23 ± 1.8 vs. 10.24 ± 5.78 µg/l; p = 0.0018), whereas adiponectin was elevated (11.75 ± 5.67 vs. 6.83 ± 2.75 µg/l; p = 0.009). For both adipocytokines, no correlations were found with characteristics such as age, gender, type of chelation, body mass index z score or haemoglobin. Leptin, but not adiponectin, was negatively correlated with ferritin (p = 0.032, r = –0.61). No correlations were found between leptin and the inflammation markers. However, adiponectin was positively correlated with endothelin-1 (p = 0.022, r = 0.63). Conclusions: Serum leptin is low in beta-thalassaemia, perhaps due to the toxic effect of iron overload on adipose tissue. Paradoxically, adiponectin levels are high and positively correlated with endothelin-1, raising questions about the pro- or anti-inflammatory role of this adipocytokine in beta-thalassaemia.
Management of Polycystic Ovary Syndrome in Childhood and Adolescence
Authors: Ojaniemi M. , Tapanainen P. , Morin-Papunen L.
Published: November 2010

Introduction: Polycystic ovary syndrome (PCOS) is a common endocrinopathy in women. It may manifest as early as in the first decade of life. Most often it becomes clinically apparent during adolescence with maturation of the hypothalamic-pituitary-ovarian axis. Clinical Features: Typical features in adolescence include irregular menstrual cycles, acne, hirsutism, obesity and signs of insulin resistance such as acanthosis nigricans. Biochemical hyperandrogenism and polycystic ovaries are often present. However, some adolescents have no evidence of clinical and biochemical hyperandrogenism despite dysfunctional polycystic ovaries. Pathogenesis: The pathogenesis of PCOS is uncertain, however, both genetic and environmental factors play a role, resulting in key features of the syndrome; disordered gonadotropin release, dysregulated steroidogenesis, ovarian and adrenal hyperandrogenism and hyperinsulinism. PCOS is often accompanied by metabolic syndrome, with abnormalities in lipid and glucose metabolism. Treatment: Treatment of PCOS is symptomatic. Lifestyle changes are a first-line intervention, however, increasing evidence suggests that metformin and estrogen-progestin combination pill may be beneficial. Conclusions: PCOS is a lifelong condition that carries long-term health risks. Several risk factors for PCOS have been identified and clinicians should be alert for this condition already in childhood and adolescence. Early intervention and counseling might be the key for prevention of co-morbidities of PCOS.
Hemianopia and Neglect Influence on Straight-Ahead Perception
Authors: Saj A. , Honoré J. , Richard C. , Bernati T. , Rousseaux M.
Published: November 2010

In spatial neglect, the pathological ipsilesional deviation of the subjective straight ahead (SSA) received both ‘translational’ and ‘rotational’ interpretations. Furthermore, hemianopia per se could also influence straight-ahead (SA) perception. Here, we aimed at disentangling the relative effects of neglect and hemianopia on the SSA by using a method analyzing translation and rotation in parallel. We included patients with a right hemisphere stroke. Ten had neglect and hemianopia, 6 neglect only, 3 hemianopia only, and 12 neither one nor the other. 15 were controls. Participants had to adjust a bar, movable in translation and rotation, SA of the navel, in darkness. Patients with spatial neglect showed systematic rightward translation, greater when hemianoptic. The rotation component appeared more variable and was influenced by the presence of a visual field defect, as most of the patients with hemianopia showed an anticlockwise rotation and most of the patients without hemianopia a clockwise rotation. Non-neglect patients and control subjects demonstrated a fair performance level. In conclusion, both neglect and hemianopia resulted in a translation error of the SSA to the ipsilesional side. In neglect patients, additional hemianopia resulted in a counterclockwise rotation. Furthermore, rotation and translation errors appeared dissociated, suggesting a different coding of these dimensions by the right posterior hemisphere.
Magnetic Resonance Imaging of Carotid Atherosclerotic Plaque in Clinically Suspected Acute Transient Ischemic Attack and Acute Ischemic Stroke
Authors: Parmar Jaywant P. , Rogers Walter J. , Mugler John P. , Baskurt Erol , Altes Talissa A. , Nandalur Kiran R. , Stukenborg George J. , Phillips C. Douglas , Hagspiel Klaus D. , Matsumoto Alan H. , Dake Michael D. , Kramer Christopher M.
Published: November 2010

Background—

Carotid atherosclerotic plaque rupture is thought to cause transient ischemic attack (TIA) and ischemic stroke (IS). Pathological hallmarks of these plaques have been identified through observational studies. Although generally accepted, the relationship between cerebral thromboembolism and in situ atherosclerotic plaque morphology has never been directly observed noninvasively in the acute setting.

Methods and Results—

Consecutive acutely symptomatic patients referred for stroke protocol magnetic resonance imaging/angiography underwent additional T1- and T2-weighted carotid bifurcation imaging with the use of a 3-dimensional technique with blood signal suppression. Two blinded reviewers performed plaque gradings according to the American Heart Association classification system. Discharge outcomes and brain magnetic resonance imaging results were obtained. Image quality for plaque characterization was adequate in 86 of 106 patients (81%). Eight TIA/IS patients with noncarotid pathogenesis were excluded, yielding 78 study patients (38 men and 40 women with a mean age of 64.3 years, SD 14.7) with 156 paired watershed vessel/cerebral hemisphere observations. Thirty-seven patients had 40 TIA/IS events. There was a significant association between type VI plaque (demonstrating cap rupture, hemorrhage, and/or thrombosis) and ipsilateral TIA/IS (
P
<0.001). A multiple logistic regression model including standard Framingham risk factors and type VI plaque was constructed. Type VI plaque was the dominant outcome-associated observation achieving significance (
P
<0.0001; odds ratio, 11.66; 95% confidence interval, 5.31 to 25.60).

Conclusions—

In situ type VI carotid bifurcation region plaque identified by magnetic resonance imaging is associated with ipsilateral acute TIA/IS as an independent identifier of events, thereby supporting the dominant disease pathophysiology.
Identification of Genomic Predictors of Atrioventricular Conduction
Authors: Denny Joshua C. , Ritchie Marylyn D. , Crawford Dana C. , Schildcrout Jonathan S. , Ramirez Andrea H. , Pulley Jill M. , Basford Melissa A. , Masys Daniel R. , Haines Jonathan L. , Roden Dan M.
Published: November 2010

Background—

Recent genome-wide association studies in which selected community populations are used have identified genomic signals in
SCN10A
influencing PR duration. The extent to which this can be demonstrated in cohorts derived from electronic medical records is unknown.

Methods and Results—

We performed a genome-wide association study on 2334 European American patients with normal ECGs without evidence of prior heart disease from the Vanderbilt DNA databank, BioVU, which accrues subjects from routine patient care. Subjects were identified by combinations of natural language processing, laboratory queries, and billing code queries of deidentified medical record data. Subjects were 58% female, of mean (±SD) age 54±15 years, and had mean PR intervals of 158±18 ms. Genotyping was performed with the use of the Illumina Human660W-Quad platform. Our results identify 4 single nucleotide polymorphisms (rs6800541, rs6795970, rs6798015, rs7430477) linked to
SCN10A
associated with PR interval (
P
=5.73×10
−7
to 1.78×10
−6
).

Conclusions—

This genome-wide association study confirms a gene heretofore not implicated in cardiac pathophysiology as a modulator of PR interval in humans. This study is one of the first replication genome-wide association studies performed with the use of an electronic medical records–derived cohort, supporting their further use for genotype-phenotype analyses.
Proteomic Analysis of Lung Tissues From Patients With Pulmonary Arterial Hypertension
Authors: Abdul-Salam Vahitha B. , Wharton John , Cupitt John , Berryman Mark , Edwards Robert J. , Wilkins Martin R.
Published: November 2010

Background—

Pulmonary arterial hypertension is a disorder of vascular remodeling causing increased resistance to pulmonary blood flow. The expression of proteins in lungs from pulmonary arterial hypertension patients was investigated in an unbiased approach to further understand the pathobiology of this disease.

Methods and Results—

Label-free liquid chromatography tandem mass spectrometry was used to compare protein profiles in surgical samples of lungs from 8 patients with pulmonary arterial hypertension and 8 control subjects. More than 300 proteins were detected. On the basis of robust criteria, the levels of 25 proteins varied between the 2 groups. The majority of upregulated proteins were associated with cell growth, proliferation, and cell metabolism. Novel findings included an increased expression of chloride intracellular channel 4, receptor for advanced glycation end products, and periostin. Increased expression of chloride intracellular channel 4, a multifunctional protein involved in angiogenesis, and several signaling pathways implicated in pulmonary arterial hypertension—transforming growth factor-β, vascular endothelial growth factor, and bone morphogenetic protein—was confirmed by Western blotting and localized predominantly to endothelial cells in occlusive and plexiform vascular lesions.

Conclusions—

Label-free proteomics identified differences in the expression of several proteins in the pulmonary arterial hypertension lung, many of which are relevant to the disease process. Increased expression of chloride intracellular channel 4 may be pertinent to the disorganized angiogenesis of plexiform lesions.
Diagnostic Study of the Effects of a Large City on Heavy Rainfall as Revealed by an Ensemble Simulation: A Case Study of Central Tokyo, Japan
Authors: Inamura Tomohiko , Izumi Takeki , Matsuyama Hiroshi
Published: November 2010

This study was undertaken to investigate the effects of a large city on heavy rainfall in Tokyo, Japan, based on an ensemble simulation with a large number of members. An ensemble simulation (24 members) of eight brief heavy rainfall events that occurred from 1999 to 2007 was performed. The ensemble simulation was performed using five objective analysis datasets [Japanese 25-yr Reanalysis (JRA-25), Regional Analysis (RANAL), NCEP Final Operational Global Analysis (NCEP-FNL), NCEP–Department of Energy Global Reanalysis 2 (NCEP/DOE-R2), and Global Analysis (GANAL)]. Land-use distributions of two types were prepared for numerical simulations: actual land use and virtual land use, in which all urban land use was converted to vegetation. Each member was simulated using actual land use and virtual land use. The effects of the urban area were then assessed by comparing the results of these simulations. Results indicate no large differences in the wind systems of the Kanto plain (roughly 100 km × 100 km), where Tokyo is located, even if cities were converted entirely to vegetation. The influence of cities on wind systems of this scale was negligible. However, changes of wind convergence were found leeward of the urban area, which increased the horizontal vapor flux there. The precipitation also increased there due to the urban effects, despite the decrease in vertical vapor flux from the land surface. It is concluded that urban effects for Tokyo alter the wind characteristics leeward of the urban area and develop wind convergence and rainfall there.
The Effect of Signal-to-Noise Ratio on the Study of Sea Level Trends
Authors: Hamlington B. D. , Leben R. R. , Nerem R. S. , Kim K.-Y.
Published: November 2010

Extracting secular sea level trends from the background ocean variability is limited by how well one can correct for the time-varying and oscillating signals in the record. Many geophysical processes contribute time-dependent signals to the data, making the sea level trend difficult to detect. In this paper, cyclostationary empirical orthogonal functions (CSEOFs) are used to quantify and improve the signal-to-noise ratio (SNR) between the secular trend and the background variability, obscuring this trend in the altimetric sea level record by identifying and removing signals that are physically interpretable. Over the 16-yr altimetric record the SNR arising from the traditional least squares method for estimating trends can be improved from 4.0% of the ocean having an SNR greater than one to 9.9% when using a more sophisticated statistical method based on CSEOFs. From a standpoint of signal detection, this implies that the secular trend in a greater portion of the ocean can be estimated with a higher degree of confidence. Furthermore, the CSEOF method improves the standard error on the least squares estimates of the secular trend in 97% of the ocean. The convergence of the SNR as the record length is increased is used to estimate the SNR of sea level trends in the near future as more measurements become available from near-global altimetric sampling.
Discourses of Remediation: Low-Income Students and Academic Identities
Authors: Colyar Julia E. , Stich Amy E.
Published: November 2010

This article draws on the framework of new literacy studies (Gee, 1996, 2005) to explore remedial students’ academic identities. The authors use discourse analysis to examine students’ written assignments from one remedial summer bridge course. Student-written assignments include themes and rhetorical devices that suggest the complexities of negotiating academic identities. In particular, low-income student participants express uncertainty about their academic selves. The authors offer this framework as one means of further exploring remedial student experiences.
A modeling and simulation-based methodology to support dynamic negotiation for web service applications
Authors: Jarrah Moath , Zeigler Bernard
Published: November 2010

Different negotiation engineering domains require the system designer to tailor the negotiation framework according to the domain under which it will be used. This process of system design is timely consuming when supporting different geographically distributed and dynamic environments. Here we show a methodology to design negotiation systems by integrating domain-dependent message structure ontology with domain-independent marketplace architecture. The methodology gives the system designers a powerful modeling tool that can be used to tailor the framework in order to support different negotiation behaviors under different domains. The system entity structure formalism is used to build the domain-dependent ontology while the finite deterministic discrete event system formalism is used to build the marketplace model. The discrete event system with service oriented architecture simulation environment was employed to demonstrate a proof of concept of applicability to web service domains.
Hobbes contra Liberty of Conscience
Authors: Tralau Johan
Published: November 2010

It has often been argued that, notwithstanding his commitment to the authoritarian state, Thomas Hobbes is a champion of the “minimal” version of liberty of conscience: namely, the freedom of citizens to think whatever they like as long as they obey the law. Such an interpretation renders Hobbes’s philosophy more palatable to contemporary society. Yet the claim is incorrect. Alongside his notion of “private” conscience, namely, Hobbes develops a conception of conscience as a public phenomenon. In the following, it is argued that this inconsistency serves the purpose of deception: it holds out the possibility of dissent while making it impossible to utilise. Arguably, moreover, this is the proper hermeneutical approach to take to Hobbes’s inconsistencies in general. Indeed, said inconsistencies ought to alert contemporary normative theorists to the instability of the “minimal” version of liberty of conscience attributed to Hobbes: Hobbes himself, namely, shows that it is insufficient.
Linearization of switched non-linear systems
Authors: Yanyan Yuan  , Yupeng Qiao  , Daizhan Cheng
Published: November 2010

The problem of static state feedback linearization of switched non-linear systems is investigated. First, we consider the regular state feedback linearization. In this case, the single-input switched system is considered first. A necessary and sufficient condition is provided, which contains an uncertain single variable function. Then the result is extended to a multiple input case. Secondly, the problem of non-regular static state feedback linearization is considered. Using semi-tensor product, some easily verifiable sufficient conditions are obtained. Then some examples are presented to illustrate the linearization process.