bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehension of Simple Quantifiers: Empirical Evaluation of a Computational Model
Authors: Szymanik Jakub , Zajenkowski Marcin
Published: March 2010

We examine the verification of simple quantifiers in natural language from a computational model perspective. We refer to previous neuropsychological investigations of the same problem and suggest extending their experimental setting. Moreover, we give some direct empirical evidence linking computational complexity predictions with cognitive reality. In the empirical study we compare time needed for understanding different types of quantifiers. We show that the computational distinction between quantifiers recognized by finite‐automata and push‐down automata is psychologically relevant. Our research improves upon, the hypotheses and explanatory power of recent neuroimaging studies as well as provides evidence for the claim that human linguistic abilities are constrained by computational complexity.
Cross‐National Comparisons of Complex Problem‐Solving Strategies in Two Microworlds
Authors: Güss C. Dominik , Tuason Ma. Teresa , Gerhard Christiane
Published: March 2010

Research in the fields of complex problem solving (CPS) and dynamic decision making using microworlds has been mainly conducted in Western industrialized countries. This study analyzes the CPS process by investigating thinking‐aloud protocols in five countries. Participants were 511 students from Brazil, Germany, India, the Philippines, and the United States who worked on two microworlds. On the basis of cultural‐psychological theories, specific cross‐national differences in CPS strategies were hypothesized. Following theories of situatedness of cognition, hypotheses about the specific frequency of problem‐solving strategies in the two microworlds were developed. Results of the verbal protocols showed (a) modification of the theoretical CPS model, (b) task dependence of CPS strategies, and (c) cross‐national differences in CPS strategies. Participants’ CPS processes were particularly influenced by country‐specific problem‐solving strategies.
The Interactive Evolution of Human Communication Systems
Authors: Fay Nicolas , Garrod Simon , Roberts Leo , Swoboda Nik
Published: March 2010

This paper compares two explanations of the process by which human communication systems evolve: iterated learning and social collaboration. It then reports an experiment testing the social collaboration account. Participants engaged in a graphical communication task either as a member of a community, where they interacted with seven different partners drawn from the same pool, or as a member of an isolated pair, where they interacted with the same partner across the same number of games. Participants’ horizontal, pair‐wise interactions led “bottom up” to the creation of an effective and efficient shared sign system in the community condition. Furthermore, the community‐evolved sign systems were as effective and efficient as the local sign systems developed by isolated pairs. Finally, and as predicted by a social collaboration account, and not by an iterated learning account, interaction was critical to the creation of shared sign systems, with different isolated pairs establishing different local sign systems and different communities establishing different global sign systems.
Children’s Production of Unfamiliar Word Sequences Is Predicted by Positional Variability and Latent Classes in a Large Sample of Child‐Directed Speech
Authors: Matthews Danielle , Bannard Colin
Published: March 2010

We explore whether children’s willingness to produce unfamiliar sequences of words reflects their experience with similar lexical patterns. We asked children to repeat unfamiliar sequences that were identical to familiar phrases (e.g.,A piece of toast) but for one word (e.g., a novel instantiation ofA piece ofX, likeA piece of brick). We explore two predictions—motivated by findings in the statistical learning literature—that children are likely to have detected an opportunity to substitute alternative words into the final position of a four‐word sequence if (a) it is difficult to predict the fourth word given the first three words and (b) the words observed in the final position are distributionally similar. Twenty‐eight 2‐year‐olds and thirty‐one 3‐year‐olds were significantly more likely to correctly repeat unfamiliar variants of patterns for which these properties held. The results illustrate how children’s developing language is shaped by linguistic experience.
Subjective intensity of pain during supportive periodontal treatment using a sonic scaler or an Er:YAG laser
Authors: Braun Andreas , Jepsen Søren , Deimling Daniela , Ratka‐Krüger Petra
Published: March 2010

Braun A, Jepsen S, Deimling D, Ratka‐Krüger P. Subjective intensity of pain during supportive periodontal treatment using a sonic scaler or an Er:YAG laser. J Clin Periodontol 2010; 37: 340–345. doi: 10.1111/j.1600‐051X.2010.01536.x

Objective: To assess the subjective intensities of pain during supportive periodontal treatment using a sonic scaler or an Er:YAG laser.

Material and Methods: Forty patients with two residual periodontal pockets following conventional periodontal therapy were treated using a sonic scaler and an Er:YAG laser in a split‐mouth design. A visual analogue scale was used for pain assessment directly after each treatment procedure. Additionally, pain was recorded during the treatment of 11 patients at intervals of 0.5 s using an inter‐modal intensity comparison.

Results: Pain assessment during treatment showed that laser treatment (median pain score: 0.71 U, maximum: 9.94 U, minimum: 0 U) caused less pain than the sonic device (median pain score: 2.17 U, maximum: 11.26 U, minimum: 0 U) (p<0.05) with no difference in the treatment time (p>0.05). These results could be confirmed by the visual analogue scale: pain scores assessed after laser treatment (median: 1 U, maximum: 7 U, minimum: 0 U) were lower than those after sonic instrumentation (median: 3.5 U, maximum: 7.5 U, minimum: 0 U) (p<0.05).

Conclusions: Using an Er:YAG laser during supportive periodontal treatment, painful sensations can be reduced compared with sonic scaler instrumentation.
Periodontal wound healing/regeneration following implantation of recombinant human growth/differentiation factor‐5 in a β‐tricalcium phosphate carrier into one‐wall intrabony defects in dogs
Authors: Lee Jung‐Seok , Wikesjö Ulf M. E. , Jung Ui‐Won , Choi Seong‐Ho , Pippig Susanne , Siedler Michael , Kim Chong‐Kwan
Published: March 2010

Lee J‐S, Wikesjö UME, Jung U‐W, Choi S‐H, Pippig S, Siedler M, Kim C‐K. Periodontal wound healing/regeneration following implantation of recombinant human growth/differentiation factor‐5 in a β‐tricalcium phosphate carrier into one‐wall intrabony defects in dogs. J Clin Periodontol 2010; 37: 382–389. doi: 10.1111/j.1600‐051X.2010.01544.x

Objective: Recombinant human growth/differentiation factor‐5 (rhGDF‐5) is being evaluated as a candidate therapy in support of periodontal regeneration. The objective of this study was to evaluate periodontal wound healing/regeneration following the application of rhGDF‐5 on a particulate β‐tricalcium phosphate (β‐TCP) carrier using an established defect model.

Materials and Methods: Bilateral 4 × 5 mm (width × depth), one‐wall, critical‐size, intrabony periodontal defects were surgically created at the mandibular second and fourth pre‐molar teeth in 15 Beagle dogs. Unilateral defects in five animals received rhGDF‐5/β‐TCP (Scil Technology GmbH); five animals received β‐TCP solo; and five animals served as sham‐surgery controls. Contralateral sites received treatments reported elsewhere. The animals were sacrificed following an 8‐week healing interval for histological examination.

Results: Clinical healing was generally uneventful. Sites implanted with rhGDF‐5/β‐TCP exhibited greater enhanced cementum and bone formation compared with β‐TCP and sham‐surgery controls; cementum regeneration averaged (± SD) 3.83 ± 0.73 versus 1.65 ± 0.82 and 2.48 ± 1.28 mm for the controls (p<0.05). Corresponding values for bone regeneration height averaged 3.26 ± 0.30 versus 1.70 ± 0.66 and 1.68 ± 0.49 mm (p<0.05), and bone area 10.45 ± 2.26 versus 6.31 ± 2.41 and 3.00 ± 1.97 mm2 (p<0.05). Cementum regeneration included cellular/acellular cementum with or without a functionally oriented periodontal ligament. A non‐specific connective tissue attachment was evident in the sham‐surgery control. Controls exhibited mostly woven bone with primary osteons, whereas rhGDF‐5/β‐TCP sites showed a noticeable extent of lamellar bone. Sites receiving rhGDF‐5/β‐TCP or β‐TCP showed some residual β‐TCP granules apparently undergoing biodegradation without obvious differences between the sites. Sites receiving β‐TCP alone commonly showed residual β‐TCP granules sequestered in the connective tissue or fibrovascular marrow.

Conclusion: rhGDF‐5/β‐TCP has a greater potential to support the regeneration of the periodontal attachment. Long‐term studies are necessary to confirm the uneventful maturation of the regenerated tissues.
Perch production in forest lakes: the contribution of abiotic and biotic factors
Authors: Horppila J. , Olin M. , Vinni M. , Estlander S. , Nurminen L. , Rask M. , Ruuhijärvi J. , Lehtonen H.
Published: March 2010

Horppila J, Olin M, Vinni M, Estlander S, Nurminen L, Rask M, Ruuhijärvi J, Lehtonen H. Perch production in forest lakes: the contribution of abiotic and biotic factors. Ecology of Freshwater Fish 2010: 19: 257–266. © 2010 John Wiley & Sons A/S

Abstract –  The biomass, growth and production of perch (Perca fluviatilis (L.)) in five humic forest lakes in southern Finland were estimated and the abiotic and biotic factors contributing to the between‐lake differences were explored. The average perch biomass in the study lakes varied from 13.1 to 45.6 kg·ha−1 and annual production from 6.0 to 16.5 kg·ha−1. The highest biomass and production were found in Lake Majajärvi with highest water colour and nutrient concentration. Variability in fish density rather than in individual growth rate seemed to be the main factor behind the between‐lake differences in perch production. No dependence of perch production on water transparency was found, because transparency had a stronger effect on individual growth than on fish density. The length increment of perch in their second year increased significantly with water transparency but at older ages no such dependence was found. At age of 4 years, the growth rate of perch decreased with perch density, indicating intraspecific competition for benthic food resources. At age of 7 years, the growth rate increased with increasing roach (Rutilus rutilus (L.)) abundance, suggesting that roach served as a resource for piscivorous perch. The effects of predatory top‐down control on perch populations were probably obscured due to the variable size and water quality of the study lakes.
REVIEW ARTICLE: Governing the Invasive Trophoblast: Current Aspects on Intra‐ and Extracellular Regulation
Authors: Fitzgerald Justine S. , Germeyer Ariane , Huppertz Berthold , Jeschke Udo , Knöfler Martin , Moser Gerit , Scholz Christoph , Sonderegger Stefan , Toth Bettina , Markert Udo R.
Published: March 2010

Citation Fitzgerald JS, Germeyer A, Huppertz B, Jeschke U, Knöfler M, Moser G, Scholz C, Sonderegger S, Toth B, Markert UR. Governing the invasive trophoblast: current aspects on intra‐ and extracellular regulation. Am J Reprod Immunol 2010

This review summarizes several aspects especially of regulating factors governing trophoblast invasion. Those include the composition of the extracellular matrix containing a variety of matrix metalloproeinases and their inhibitors, but also intracellular signals. Furthermore, a newly described trophoblast subtype, the endoglandular trophoblast, is presented. Its presence may provide a possible mechanism for opening and connecting uterine glands into the intervillous space. Amongst others, two intracellular signalling pathways are crucial for regulation of trophoblast functions and development: Wnt‐ and signal transducer and activator of transcription (STAT)3 signalling. Wnt signalling promotes implantation, placentation and trophoblast differentiation. Several Wnt‐dependent cascades and regulatory mechanisms display different functions in trophoblast cells. The STAT3 signalling system is fundamental for induction and regulation of invasiveness in physiological trophoblastic cells, but also in tumours. The role of galectins (Gal) in trophoblast regulation and placenta development comes increasingly into focus. The Gal‐ 1–4, 7–10 and 12–14 have been detected in humans. Detailed information is only available for Gal‐1, ‐2, ‐3, ‐4, ‐9 and ‐12 in endometrium and decidua. Gal‐1, ‐3 and ‐13 (‐14) have been detected and studied in trophoblast cells.
Elevated NK Cell Cytotoxicity, CD158a Expression in NK Cells and Activated T Lymphocytes in Peripheral Blood of Women with IVF Failures
Authors: Chernyshov Viktor P. , Sudoma Iryna O. , Dons’koi Boris V. , Kostyuchyk Anton A. , Masliy Yulia V.
Published: March 2010

Citation Chernyshov VP, Sudoma IO, Dons’koi BV, Kostyuchyk AA, Masliy YV. Elevated NK cell cytotoxicity, CD158a expression in NK cells and activated T lymphocytes in peripheral blood of women with IVF failures. Am J Reprod Immunol 2010; 64: 58–67

Problem  The aim of this study was to evaluate the role of elevated natural killer cytotoxicity (NKc) in women with multiple implantation failures (IF) in vitro fertilization–embryo transfer (IVF–ET) cycles.

Methods of study  Seventy‐nine antiphospholipid antibodies‐negative women with IF including 33 women with elevated NKc were selected for investigation. K‐562 cell line was used to evaluate NKc. Lymphocyte subsets, intracellular cytokines [interferon (IFN)‐γ, interleukin (IL)‐4, tumour necrosis factor, IL‐10], expression of activating markers [CD69, human leukocyte antigen (HLA)‐DR], CD8, KIR (CD158a), CD95, and chemokine receptors (CXCR3, CCR4) were estimated by flow cytometry.

Results  In women with IF, levels of NKc were higher than in IVF successful women. IF was associated with higher expression of CD8, CD158a, and HLA‐DR in NK cells, activating markers in T lymphocytes, and lower levels of CCR4+ and IL‐4+ T lymphocyte subsets. Predictive value of single elevated NKc for IVF success was 0.85, but addition of two other abnormal parameters resulted in its decrease to <0.39.

Conclusions  Elevated NKc is negative factor, though not critical for implantation in IVF cycles. Immune mechanism of IVF failure includes not only elevated NKc but also some other factors, such as elevated expression of CD8 and CD158a on NK cells, T lymphocyte activation, and diminished T helper 2 parameters.
First Successful Pregnancy after Addition of Enoxaparin to Sildenafil and Etanercept Immunotherapy in Woman with Fifteen Failed IVF Cycles – Case Report
Authors: Jerzak Małgorzata , Niemiec Tomasz , Nowakowska Anna , Klochowicz Monika , Górski Andrzej , Baranowski Włodzimierz
Published: March 2010

Citation Jerzak M, Niemiec T, Nowakowska A, Klochowicz M, Górski A, Baranowski W. First successful pregnancy after addition of enoxaparin to sildenafil and etanercept immunotherapy in woman with fifteen failed in vitro fertilization (IVF) cycles – case report. Am J Reprod Immunol 2010; 64: 93–96

Problem  Does addition of enoxaparin to sildenafil and etanercept immunotherapy improve IVF outcome?

Methods  Report of a striking case with 15 IVF failures.

Result  When enoxaparin was added, the 16th IVF cycle generated a healthy male baby.

Conclusions  Combination therapy that includes a heparin may allow successful IVF outcome and this issue merits further study.
Evaluation of thyroglobulin expression in murine reproductive organs during pregnancy
Authors: Moravej Ali , Jeddi‐Tehrani Mahmood , Salek‐Moghaddam Ali R. , Dokouhaki Pouneh , Ghods Roya , Rabbani Hodjatallah , Kazemi‐Sefat Golnaz E. , Shahbazi Mehdi , Zarnani Amir H.
Published: March 2010

Citation Moravej A, Jeddi‐Tehrani M, Salek‐Moghaddam AR, Dokouhaki P, Ghods R, Rabbani H, Kazemi‐Sefat GE, Shahbazi M, Zarnani AH. Evaluation of thyroglobulin expression in murine reproductive organs during pregnancy. Am J Reprod Immunol 2010; 64: 97–103

Problem  In pregnant women with antithyroglobulin antibody, prevalence of abortion is 2–4 fold higher compared to normal controls. Direct effect of such harmful autoantibodies on female reproductive organs may serve a role in pregnancy loss.

Method of study  Expression of thyroglobulin in decidua, placenta, and ovary of pregnant Balb/c mice ((Balb/c×Balb/c and Balb/c×C57BL/6) during early, middle, and late stages of pregnancy was evaluated. Expression of thyroglobulin was investigated in these tissues by semi‐quantitative RT‐PCR. In addition, polyclonal antithyroglobulin antibody was produced, and expression of thyroglobulin protein in aforesaid tissues was evaluated by immunohistochemistry and dot‐blot analysis.

Results  The results showed that thyroglobulin message is not expressed in placenta, decidua, or ovary in any stages of pregnancy. The same results were obtained at the protein level.

Conclusion  It is likely that antithyroglobulin antibodies have no direct detrimental effect on such organs in patients with thyroid autoimmunity suffering from recurrent abortion.
Problem Department
Authors: Willerding Margaret F.
Published: March 2010

This department aims to provide problems of varying degrees of difficulty which will interest anyone engaged in the study of mathematics.

All readers are invited to propose problems and to solve problems here proposed. Drawings to illustrate the problems should be well done in India ink. Problems and solutions will be credited to their authors. Each solution or proposed problem sent the Editor should have the author's name introducing the problem or solution as on the following pages.

The Editor of the Department desires to serve her readers by making it interesting and helpful to them. Address suggestions and problems to Margaret F. Willerding, San Diego State College, San Diego, Calif.
Problem Department
Authors: Willerding Margaret F.
Published: March 2010

This department aims to provide problems of varying degrees of difficulty which will interest anyone engaged in the study of mathematics.

All readers are invited to propose problems and to solve problems here proposed. Drawings to illustrate the problems should be well done in India ink. Problems and solutions will be credited to their authors. Each solution or proposed problem sent the Editor should have the author's name introducing the problem or solution as on the following pages.

The editor of the Department desires to serve her readers by making it interesting and helpful to them. Address suggestions and problems to Margaret F. Willerding, San Diego State College, San Diego, Calif., 92115.
Problem Department
Authors: Willerding Margaret F.
Published: March 2010

This department aims to provide problems of varying degrees of difficulty which will interest anyone engaged in the study of mathematics.

All readers are invited to propose problems and to solve problems here proposed. Drawings to illustrate the problems should be well done in India ink. Problems and solutions will be credited to their authors. Each solution or proposed problem sent the Editor should have the author's name introducing the problem or solution as on the following pages.

The Editor of the Department desires to serve her readers by making it interesting and helpful to them. Address suggestions and problems to Margaret F. Willerding, Mathematics Dept., San Diego State University; San Diego Calif., 92115.
Prevalence and serum protein values of strangles (Streptococcus equi) affected mules at Remount Depot, Sargodha (Pakistan)
Authors: Ijaz M. , Khan M. S. , Khan M. A. , Avais M. , Maqbool A. , Ali M. M. , Shahzad W.
Published: March 2010

The prevalence ofStreptococcus equi serovar equi(S.equi) in nasal discharge and pus samples from sub‐mandibular lymph nodes in mules at the Remount Depot, Sargodha was examined and total serum proteins, serum albumin, serum globulin and fibrinogen measured. A total of 250 nasal swabs and pus samples were collected from mules and examined microbiologically: 99 (39.6%) were positive forS. equi. A higher occurrence ofS. equiwas recorded in foals as compared to adults. The concentrations of total serum protein, serum globulin and fibrinogen were significantly increased (P<0.05), while the concentration of serum albumin significantly decreased (P<0.05) in strangles‐affected mules. It was concluded that increased total serum proteins, serum globulin and fibrinogen along with decreased serum albumin were important indicators of infection byS. equiin mules.
Relationships between race earnings and horse age, sex, gait, track surface and number of race starts for Thoroughbred and Standardbred racehorses in North America
Authors: CHEETHAM J. , RIORDAN A. S. , MOHAMMED H. O. , McILWRAITH C. W. , FORTIER L. A.
Published: March 2010

Reasons for performing study:There is no consensus on objective outcome measures that can be used to determine if a medical or surgical treatment affects race performance.

Objective:To determine the association between 2 commonly used outcome measures (total starts and total earnings) and age, sex, gait and race surface.

Methods:A cross‐sectional study was performed using the race performance data for all Thoroughbred horses age 2, 3, 4 and 5 years racing in the United States, and Standardbred horses of the same ages racing in the United States and Canada during the year 2006. Median earnings and starts were determined for each combination of age, sex and track surface (for Thoroughbred) or gait (for Standardbred). The effect these variables had on starts on race earnings ($) was determined using linear regression.

Results:Race records for 68,649 Thoroughbreds and 25,830 Standardbreds were obtained. All independent variables (age, breed, sex, gait, track surface and total number of starts) had a significant impact on total earnings (P<0.0001).

Conclusions:The data show considerable variation across age groups and track surfaces for Thoroughbreds and across age groups for Standardbreds. They also show that the decision to use earnings or starts as outcome measures could have a marked effect on reported success for a particular treatment.

Potential relevance:Both earning and start data should be reported in studies evaluating outcome following surgery or other intervention. Considerations of age, breed, sex, track surface and gait should be included in the design of these studies.
Elevating the uterus (uteropexy) of five mares by laparoscopically imbricating the mesometrium
Authors: BRINK P. , SCHUMACHER J. , SCHUMACHER J.
Published: March 2010

Reasons for performing study:There is a need for study of a method for restoring a ventrally positioned uterus to a horizontal position involving fertility of mares with delayed uterine clearance.

Hypothesis:A ventrally‐angled uterus can be elevated to a horizontal position using a laparoscopic technique.

Objective:To develop a laparoscopic technique of imbricating the mesometria to elevate the uterus to a horizontal position.

Methods:The right and left mesometria of 5 pluriparous mares, all barren for 1–8 years (mean 3.8 years), with a pendulous, ventrally‐angled uterus were shortened laparoscopically, by imbrication, with the mares standing, to raise the uterine body and horns to a horizontal position. Sutures were placed through the dorsal aspect of the uterine body and uterine horn and the adjacent region of the mesometrium using a simple continuous suture pattern.

Results:The uterus of all 5 mares was elevated successfully to a horizontal position. Three of the mares became pregnant the same year, without other treatment, after the procedure.

Conclusions:A pendulous, ventrally‐angled uterus can be returned to a normal, horizontal position by imbricating the mesometria, using a laparoscopic technique.

Potential relevance:Elevating a ventrally‐angled uterus to a horizontal position may improve egress of uterine debris, thereby improving fertility.
Particle Image Velocimetry and Computational Fluid Dynamics Analysis of Fuel Cell Manifold
Authors: Lebæk Jesper , Andreasen Marcin Blazniak , Andresen Henrik Assenholm , Bang Mads , Kær Søren Knudsen
Published: March 2010

The inlet effect on the manifold flow in a fuel cell stack was investigated by means of numerical methods (computational fluid dynamics) and experimental methods (particle image velocimetry). At a simulated high current density situation the flow field was mapped on a 70 cell simulated cathode manifold. Three different inlet configurations were tested: plug flow, circular inlet, and a diffuser inlet. A very distinct jet was formed in the manifold, when using the circular inlet configuration, which was confirmed both experimentally and numerically. This jet was found to be an asymmetric confined jet, known as the symmetry-breaking bifurcation phenomenon, and it is believed to cause a significant maldistribution of the stack flow distribution. The investigated diffuser design proved to generate a much smoother transition from the pipe flow to the manifold flow with a subsequent better flow distribution. A method was found in the literature to probe if there is a risk of jet asymmetry; it is however recommended by the author to implement a diffuser design, as this will generate better stack flow distribution and less head loss. Generally, the numerical and experimental results were found in to be good agreement, however, a detailed investigation revealed some difference in the results.
Modeling and Simulations of Polymer Electrolyte Membrane Fuel Cells With Poroelastic Approach for Coupled Liquid Water Transport and Deformation in the Membrane
Authors: Yesilyurt Serhat
Published: March 2010

Performance degradation and durability of polymer electrolyte membrane (PEM) fuel cells depend strongly on transport and deformation characteristics of their components especially the polymer membrane. Physical properties of membranes, such as ionic conductivity and Young’s modulus, depend on the water content that varies significantly with operating conditions and during transients. Recent studies indicate that cyclic transients may induce hygrothermal fatigue that leads to the ultimate failure of the membrane shortening its lifetime and, thus, hindering the reliable use of PEM fuel cells for automotive applications. In this work, we present two-dimensional simulations and analysis of coupled deformation and transport in PEM fuel cells to improve the understanding of membrane deformation under steady-state and transient conditions. A two-dimensional cross section of anode and cathode gas diffusion layers, and the membrane sandwiched between them is modeled using Maxwell–Stefan equations for species transport in gas diffusion layers, Biot’s poroelasticity, Darcy’s law for deformation and water transport in the membrane, and Ohm’s law for ionic currents in the membrane and electric currents in the gas diffusion layers. Steady-state deformation and transport of water in the membrane, transient responses to step changes in load, and relative humidity of the anode and cathode are obtained from simulation experiments, which are conducted by means of a commercial finite-element package, COMSOL MULTIPHYSICS.
Fabrication of Metallic Bipolar Plates for Proton Exchange Membrane Fuel Cell by Flexible Forming Process-Numerical Simulations and Experiments
Authors: Peng Linfa , Liu Dong’an , Hu Peng , Lai Xinmin , Ni Jun
Published: March 2010

PEM fuel cell nowadays is expensive for widespread commercialization, though it has obvious advantages, such as high efficiency, high power density, fast startup and high system robustness. As one of the most important and costliest components in the PEM fuel cell stack, bipolar plates (BPPs) account for more than 80% of the weight and 30% of the cost of the whole stack. By replacing the conventional graphitic or machined thick metal plates with the lightweight and low-cost thin metallic sheet BPP with sustainable coating, PEM fuel cell will become an attractive choice for manufacturers. In this study, the fabrication of micro-channel features by flexible forming process (FFP) are studied first, which demonstrates the feasibility of using FFP to manufacture thin metallic BPPs. Then, the obtained knowledge is applied onto the fabrication of real thin metallic BPPs with some process amendment. The first investigation of this study focuses on the forming of micro-channel features with 100 μm thickness stainless steel sheet. A finite element analysis (FEA) model is built and key process parameters (hardness of soft tools used in FFP, friction coefficients between contact surfaces) associated with the formability of BPPs are studied. The FEA is partly validated by the experiments. In the second investigation, finite element analysis method is adopted in the design of the BPP forming process. Based on the numerical simulation results, the die setup is prepared and some process amendments are made to improve the formability of BPPs. As a result, high quality metallic BPPs are obtained in the latter experiments, which demonstrates the feasibility to manufacture the metallic bipolar plate by FFP.
Water Removal From Hydrophilic Fuel Cell Channels
Authors: Caulk D. A.
Published: March 2010

This paper describes an approximate method for analyzing two-phase flow of gas and liquid water in fuel cell channels, whose surfaces are sufficiently hydrophilic for liquid water to wick spontaneously into the channel corners. This analysis is used to address the important question of whether the gas flow at typical stoichiometries in such channels is sufficient to remove all the liquid water generated in a proton exchange membrane fuel cell. Since fuel channels are usually much narrower than they are long, it is possible to adopt the usual approximations of lubrication theory and to decompose the general solution for the liquid motion into two parts: (1) that driven by the channel pressure gradient and (2) that driven by surface shear stress from the faster moving gas. When both parts of the solution are combined with the mass balance equations, it is possible to derive a pair of partial differential equations for the water depth and gas flow rate that depend on distance down the channel and time. Steady solutions of these equations are explored to determine the amount of liquid water that accumulates in the channel over a broad range of fuel cell operating conditions.
Mutations in Fibrillin-1 Cause Congenital Scleroderma: Stiff Skin Syndrome
Authors: Loeys B. L. , Gerber E. E. , Riegert-Johnson D. , Iqbal S. , Whiteman P. , McConnell V. , Chillakuri C. R. , Macaya D. , Coucke P. J. , De Paepe A. , Judge D. P. , Wigley F. , Davis E. C. , Mardon H. J. , Handford P. , Keene D. R. , Sakai L. Y. , Dietz H. C.
Published: March 2010

Stiff skin syndrome, an autosomal dominant congenital form of scleroderma, is caused by mutations in the domain of fibrillin-1 that mediates integrin binding.
Targeting Robo4-Dependent Slit Signaling to Survive the Cytokine Storm in Sepsis and Influenza
Authors: London Nyall R. , Zhu Weiquan , Bozza Fernando A. , Smith Matthew C. P. , Greif Daniel M. , Sorensen Lise K. , Chen Luming , Kaminoh Yuuki , Chan Aubrey C. , Passi Samuel F. , Day Craig W. , Barnard Dale L. , Zimmerman Guy A. , Krasnow Mark A. , Li Dean Y.
Published: March 2010

Blunting increased vascular permeability caused by an infection-induced cytokine storm with a Slit ligand increased survival in rodent models of sepsis and viral infection.
The SigF Regulon in
Mycobacterium smegmatis
Reveals Roles in Adaptation to Stationary Phase, Heat, and Oxidative Stress
Authors: Hümpel Anja , Gebhard Susanne , Cook Gregory M. , Berney Michael
Published: March 2010

SigF is an alternative sigma factor that is highly conserved among species of the genus
Mycobacterium
. In this study we identified the SigF regulon in
Mycobacterium smegmatis
using whole-genome microarray and promoter consensus analyses. In total, 64 genes in exponential phase and 124 genes in stationary phase are SigF dependent (
P
< 0.01, >2-fold expression change). Our experimental data reveal the SigF-dependent promoter consensus GTTT-N
(15-17)
-GGGTA for
M. smegmatis
, and we propose 130 potential genes under direct control of SigF, of which more than 50% exhibited reduced expression in a Δ
sigF
strain. We previously reported an increased susceptibility of the Δ
sigF
strain to heat and oxidative stress, and our expression data indicate a molecular basis for these phenotypes. We observed SigF-dependent expression of several genes purportedly involved in oxidative stress defense, namely, a heme-containing catalase, a manganese-containing catalase, a superoxide dismutase, the starvation-induced DNA-protecting protein MsDps1, and the biosynthesis genes for the carotenoid isorenieratene. Our data suggest that SigF regulates the biosynthesis of the thermoprotectant trehalose, as well as an uptake system for osmoregulatory compounds, and this may explain the increased heat susceptibility of the Δ
sigF
strain. We identified the regulatory proteins SigH3, PhoP, WhiB1, and WhiB4 as possible genes under direct control of SigF and propose four novel anti-sigma factor antagonists that could be involved in the posttranslational regulation of SigF in
M. smegmatis
. This study emphasizes the importance of this sigma factor for stationary-phase adaptation and stress response in mycobacteria.
Improving end of life care for nursing home residents: an analysis of hospital mortality and readmission rates
Authors: Ahearn D J , Jackson T B , McIlmoyle J , Weatherburn A J
Published: March 2010

Introduction

Despite concern that many nursing home residents who become acutely unwell are admitted to hospital for often futile and distressing treatment, no previous studies analysing survival and readmission rates of this cohort were found in the literature.

Objective

To study survival and readmission rates of nursing home patients admitted acutely to general medicine.

Method

Analysis of all admissions to the acute medical unit of a busy district general hospital over a 94 day period, comparing nursing home residents with all admitted patients aged over 70 years.

Results

Nursing home residents were significantly less likely to survive the admission than elderly people living in the community. 33.9% of nursing home residents did not survive the admission and 51.6% died within 6 weeks of admission. Of those discharged alive, 41.5% were readmitted or died within 6 weeks. Patients with a higher level of comorbidity were less likely to survive the admission or live to 6 weeks.

Discussion

These findings raise the need for careful ‘advance care planning’. This should become commonplace for nursing home residents to improve end of life care and reduce hospital admissions in patients unlikely to survive. The judicious use of ‘Preferred Priorities for Care’ documents, ‘do-not-hospitalise’ orders, and the establishment of a dedicated multidisciplinary team involving primary and secondary care is proposed to help achieve these aims.

Conclusion

Survival rates in nursing home residents admitted to an acute medical unit are low, and measures are suggested to reduce inappropriate admissions and facilitate improved end of life care.
Epigenetic chromatin modifications inBrassicagenomes
Authors: Braszewska-Zalewska Agnieszka , Bernas Tytus , Maluszynska Jolanta
Published: March 2010

Epigenetic modifications such as histone and DNA methylation are highly conserved among eukaryotes, although the nuclear patterns of these modifications vary between different species. Brassica species represent a very attractive model for analysis of epigenetic changes because of their differences in genome size, ploidy level, and the organization of heterochromatin blocks. Brassica rapa and B. oleracea are diploid species, and B. napus is an allotetraploid species that arose from the hybridization of these two diploids. We found that patterns of DNA and histone H3 methylation differ between Brassica species. The most prominent differences concern the two diploids. DNA methylation was present exclusively in the heterochromatin only in B. rapa. In B. oleracea and B. napus this modification was detected in both euchromatin and heterochromatin. A similar pattern was observed for dimethylation of lysine 9. Dimethylation of lysine 4 is a typical marker of euchromatin in Brassica species, like it is in other plant species. We conclude that the diploid species differ in patterns of analyzed epigenetic modifications and the allotetraploid B. napus has combined patterns from both diploids. Differences in patterns of DNA and histone H3 methylation between Brassica species can be attributed mainly to the genome structure and heterochromatin localization rather than ploidy level.
Analysis of chromosomal structural polymorphisms in the St, P, and Y genomes of Triticeae (Poaceae)
Authors: Wang Qiuxia , Xiang Jishan , Gao Ainong , Yang Xinming , Liu Weihua , Li Xiuquan , Li Lihui
Published: March 2010

The St, P, and Y genomes are three important genomes in the tribe Triticeae, which includes many perennial species. To study polymorphisms within the chromosomes of the St, P, and Y genomes, a GISH–FISH method was developed that allowed them to be clearly distinguished. The karyotypes of five individuals from population Z1925 of Kengyilia grandiglumis (Keng) J.L. Yang et al. (2n = 6x = 42, StStPPYY) were analyzed. The results showed that there were structural polymorphisms in all of the chromosomes from the three individual genomes. The polymorphisms were found mainly in the terminal regions of chromosomes and infrequently near the centromeric region. Of all the chromosomes, 1P, 1St, 1Y, 2Y, 3St, and 3Y showed the most polymorphisms. The polymorphisms within the individual chromosomes suggested that more extensive and scientific conclusions regarding the origin and evolution of genomes in wild species of Triticeae would be achieved by studying a population as a sampling and analysis unit.
A candidate gene for choanal atresia in alpaca
Authors: Reed Kent M. , Bauer Miranda M. , Mendoza Kristelle M. , Armién Aníbal G.
Published: March 2010

Choanal atresia (CA) is a common nasal craniofacial malformation in New World domestic camelids (alpaca and llama). CA results from abnormal development of the nasal passages and is especially debilitating to newborn crias. CA in camelids shares many of the clinical manifestations of a similar condition in humans (CHARGE syndrome). Herein we report on the regulatory gene CHD7 of alpaca, whose homologue in humans is most frequently associated with CHARGE. Sequence of the CHD7 coding region was obtained from a non-affected cria. The complete coding region was 9003 bp, corresponding to a translated amino acid sequence of 3000 aa. Additional genomic sequences corresponding to a significant portion of the CHD7 gene were identified and assembled from the 2× alpaca whole genome sequence, providing confirmatory sequence for much of the CHD7 coding region. The alpaca CHD7 mRNA sequence was 97.9% similar to the human sequence, with the greatest sequence difference being an insertion in exon 38 that results in a polyalanine repeat (A12). Polymorphism in this repeat was tested for association with CA in alpaca by cloning and sequencing the repeat from both affected and non-affected individuals. Variation in length of the poly-A repeat was not associated with CA. Complete sequencing of the CHD7 gene will be necessary to determine whether other mutations in CHD7 are the cause of CA in camelids.
Segmental chromosomal duplications harbouring group IV CONSTANS-like genes in cereals
Authors: Cockram James , Howells Rhian M. , O’Sullivan Donal M.
Published: March 2010

Comparative mapping is an important component of map-based cloning in large-genome cereal species. We describe evidence of a segmental chromosomal duplication harbouring CONSTANS-like genes in barley that predates the divergence of the Oryzoideae (rice) and Pooideae (brachypodium, barley, wheat) clades, and discuss the implications of such events for comparative mapping and QTL cloning in temperate cereal crops.
Integration of carbon sequestration into curing process of precast concrete
Authors: Monkman Sean , Shao Yixin
Published: March 2010

The feasibility of integrating carbon sequestration into the curing of precast concrete products was investigated. Research assessed the CO2 uptake capacities of carbonation-cured concrete masonry units (CMU), concrete pavers, fibreglass-mesh reinforced cement board, cellulose-fibre board, and ladle slag fines. Three curing systems were used: (i) an open-inlet system using pressurized recovered CO2; (ii) a closed system using pressurized flue gas with 14% CO2; and (iii) a closed system using dilute CO2 under atmospheric pressure. The amount of carbon dioxide that could be sequestered in the annual North American output of the various precast concrete products was estimated. The net efficiency was calculated accounting for CO2 emissions penalty resulting from the capture, compression, and potential transport of the curing gases. Carbonation curing of the considered products could result in a net annual CO2 sequestration in US and Canada of approximately 1.8 million tonnes if recovered CO2 is used and one million tonnes if flue gas is used.
Influence of spatial inhomogeneity of tornado occurrence on estimated tornado hazard
Authors: Tan L. , Hong H. P.
Published: March 2010

Tornado hazard assessment is often based on the consideration that the spatial distribution of tornado occurrence is homogeneous in a region. Although this assumption simplifies the analysis, it could overestimate and underestimate tornado hazard for regions with lower and higher tornadic activity if an average rate of tornado occurrence is employed. The degree of overestimation and underestimation is unknown. This study is focused on the assessment of the impact of spatial inhomogeneity of tornado occurrence on the estimated tornado hazard and the development of tornado hazard maps for southern Ontario. The results indicate that at the factored design wind speed the exceedance probability for tornadic winds is much smaller than that for synoptic winds, even if the spatial inhomogeneity of tornado occurrence is considered. Furthermore, the results show that the spatial inhomogeneity of tornado occurrence has significant impact on the spatial tornado hazard level, that the return period values of tornado wind speed vary significantly over the considered region, and that the inhomogeneity must be considered in developing probabilistic quantitative tornado hazard maps.
In-plane seismic behaviour of historic stone masonry
Authors: Elmenshawi Abdelsamie , Sorour Mohamed , Mufti Aftab , Jaeger Leslie G , Shrive Nigel
Published: March 2010

Since the advent of the latest National building code of Canada, the level of intervention required to meet seismic requirements for the rehabilitation of heritage buildings has increased significantly. An example of this type of project is the rehabilitation of the West Block on Parliament Hill in Ottawa. Eight walls representative of the stone masonry in the West Block building were constructed, some with different rehabilitation schemes, and tested to investigate their in-plane seismic behaviour. The walls were double wythes of sandstone and limestone connected by a rubble core. The walls were 2750 mm high by 2000 mm wide by 540 mm thick. The rehabilitation schemes represented different ways of tying the stone wythes together, since the outer sandstone wythe has separated from the rubble core in some locations in the existing structure. The results reveal that the suggested strengthening schemes neither benefit nor degrade the in-plane seismic behaviour compared to that of a plain wall.
Using the nitro group to induce π-stacking in terthiophenes
Authors: Sears Wendy A. , MacKinnon Craig D. , Mawhinney Robert C. , Sinnemaki Lauren C. , Johnson Matthew J. , Winter A. John , Robertson Craig M.
Published: March 2010

A new synthetic route to mononitrated oligothiophenes is described, as well as the preparation of halogenated derivatives (Br, I) thereof. An unusual deep red colour is observed and explained, with the aid of DFT calculations, as arising from a significant quinoidal contribution to the molecular structure. The crystal structures of two compounds, H(C4H2S)3NO2 and Br(C4H2S)3NO2, are presented. Both compounds have planar sheets held together by intermolecular short contacts (hydrogen bonds and, for the latter, NO2···Br interactions); the sheets do not directly superimpose, so the effect of the π-stacking is not maximized. Solid-state fluorescence and extended-Hückel band-structure calculations are also presented for these materials.
Electrochemical and in situ spectroelectrochemical investigations into the redox and aggregation behaviours of phthalocyanines bearing octyl 4-phenyloxyacetate moieties
Authors: Koç İmran , Çamur Meryem , Bulut Mustafa , Özkaya A. Riza
Published: March 2010

Electrochemical and spectroelectrochemical properties of phthalocyanines (H2Pc, ZnPc, NiPc, CuPc, and CoPc) involving octyl 4-phenyloxyacetate moieties have been investigated by cyclic voltammetry and differential pulse voltammetry on Pt in dimethylsulfoxide – tetrabutylammonium perchlorate. These measurements showed that the complexes undergo subsequent one-electron reduction and oxidation processes. In situ UV–vis spectroelectrochemical measurements enabled us to identify the ligand- and metal-based redox processes, and evaluate the effect of aggregation phenomena on these processes. The cobalt complex showed both metal-based and ring-based one-electron redox processes, while the other complexes displayed only ring-based one-electron couples. It was observed that the redox processes of H2Pc, NiPc, and CuPc are coupled by aggregation phenomenon, whereas those of ZnPc and especially CoPc are not, probably owing to the difference in their axial coordinating properties.
Methicillin-resistantStaphylococcus aureusin Canada: a historical perspective and lessons learned
Authors: Cimolai Nevio
Published: March 2010

The history of methicillin-resistant Staphylococcus aureus (MRSA) in Canada has many similarities to MRSA evolution worldwide, but especially to that in the United States and United Kingdom. Reports of MRSA occurred as early as 1964, and community isolates were cited in the 1970s. Nosocomial outbreaks were becoming common by 1978 and flourished gradually thereafter. Endemic institutional MRSA became predominant in the 1990s, threatening large teaching hospitals in particular. In the last decade, both hospital-acquired and community-acquired MRSA have created major medical problems in Canada. More recently, an epidemic of Canadian community-acquired MRSA-10, has led to heightened public health concerns. Canadian contributions to MRSA science are numerous, with organized surveillance continuing to mature across the nation. A typing system for epidemic clones is now available and is being judiciously applied. Estimated costs for MRSA surveillance, treatment, and control are extraordinary, paralleling the dramatic rise in the number of MRSA isolations. Whereas surveillance continues to form an essential aspect of MRSA management, control, eradication, and overall diminution, MRSA reservoirs deserve much greater attention. Such efforts, however, must be as widely publicized in the community and in patient homes as they are in medical institutions responsible for both acute and long-term care.