bluuebunny/crossref_metadata_2025 huggingface dataset:
Geomorphic and sediment volume responses of a coastal dune complex following invasive vegetation removal
Authors: Eamer Jordan B. R. , Darke Ian B. , Walker Ian J.
Published: March 2013

This paper documents application of an established geostatistical methodology to detect significant changes in a foredune–transgressive dune complex where Parks Canada Agency (PCA) implemented a dynamic restoration program to remove invasive marram grasses (Ammophila spp.) and enhance dynamic dune habitat for an endangered species. Detailed topographic surveys of a 10 320 m2 site in the Wickaninnish Dunes in Pacific Rim National Park, British Columbia, Canada for the first year post‐treatment are compared to a pre‐restoration LiDAR baseline survey. The method incorporates inherent spatial structure in measured elevation datasets at the sub‐landscape scale and models statistically significant change surfaces within distinct, linked geomorphic units (beach, foredune, transgressive dune complex). Seasonal and annual responses within the complex are discussed and interpreted.

All geomorphic units experienced positive sediment budgets following restoration treatment. The beach experienced the highest differential volumetric change (+1656 m3) and net sediment influx (+834 m3, 0 · 19 m3 m–2) mostly from supply to the supratidal beach and incipient dune. This sediment influx occurred independent of the restoration effort and was available as a buffer against wave erosion and as supply to the landward dunes. The foredune received +200 m3 (0 · 13 m3 m‐2) and its seaward profile returned to a similar pre‐restoration form following erosion at the crest from vegetation removal and scarping by high water events. Sediment bypassing and minimal change was evident at the mid‐stoss slope with appreciable extension of depositional lobes in the lee. The transgressive dune complex experienced high accretion following restoration activity (+201 m3) and over the year (+284 m3, 0 · 07 m3 m–2) mostly from depositional lobes from the foredune, precipitation ridge growth along the downwind boundary, and growth of existing lobes within the complex. Further integration of this methodology to detect significant geomorphic changes is recommended, particularly for applications where sampling densities are limited or logistically defined. Copyright © 2013 John Wiley & Sons, Ltd.
Measurement and modeling of moisture content above an oscillating water table: implications for beach surface moisture dynamics
Authors: Schmutz Phillip P. , Namikas Steven L.
Published: March 2013

This study examined the influence of tidally‐induced oscillations of the beach water table in regulating beach surface moisture dynamics. A series of laboratory experiments were conducted to assess the influence of hysteresis and transient flow effects on surface moisture variability. The experimental apparatus utilized a column of well‐sorted fine sand partially immersed in a reservoir of water. The water level in the reservoir was raised and lowered via a diaphragm‐metering pump to simulate tidally induced fluctuations of the water table, and the moisture content profile within the column was monitored using an array of Delta‐T probes. Moisture contents at specific elevations within the column were utilized as proxies to represent various ‘surface’ elevations (relative to the high water table). Results indicate that surface moisture content behaves in a distinctly hysteretic manner. Examination of water flow scanning curves illustrated that for all surface elevations considered, higher moisture contents for a given pressure head occurred during the drying cycle than during the wetting cycle. This observation is particularly evident with shallow surface elevations (i.e. water table close to the surface) where the Haines Jump phenomenon was found to have a significant influence on moisture content dynamics. Additionally, an assessment of the accuracy of hysteretic and non‐hysteretic models to predict the measured moisture contents demonstrated that hysteretic simulations consistently provide a better representation of the observed moisture contents than non‐hysteretic simulations. A time lag was found between the respective maxima and minima in water table elevation surface moisture content. At the near surface water table positions the time lag ranged between 30 and 100 minutes, and it increased to 240 minutes (four hours) with the high water table at 60 cm below the surface. Copyright © 2013 John Wiley & Sons, Ltd.
Differential nuclear organization of translocation‐prone genes in nonmalignant B cells from patients with t(14;16) as compared with t(4;14) or t(11;14) myeloma
Authors: Martin Lorri D. , Harizanova Jana , Righolt Christiaan H. , Zhu George , Mai Sabine , Belch Andrew R. , Pilarski Linda M.
Published: March 2013

Gene organization in nonmalignant B cells from t(4;14) and t(11;14) multiple myeloma (MM) patients differs from that of healthy donors. Among recurrent IGH translocations in MM, the frequency of t(4;14) (IGH and FGFR3) or t(11;14) (IGH and CCND1) is greater than the frequency of t(14;16) (IGH and MAF). Gene organization in t(14;16) patients may influence translocation potential of MAF with IGH. In patients, three‐dimensional FISH revealed the positions of IGH, CCND1, FGFR3, and MAF in nonmalignant B cells that are likely similar to those when MM first arose, compared with B cells from healthy donors. Overall, IGH occupies a more central nuclear position while MAF is more peripherally located. However, for B cells from t(4;14) and t(11;14) patients, IGH and FGFR3, or IGH and CCND1 are found in spatial proximity: IGH and MAF are not. This differs in B cells from t(14;16) patients and healthy donors where IGH is approximately equidistant to FGFR3, CCND1, and MAF, suggesting that gene organization in t(14;16) patients is different from that in t(4;14) or t(11;14) patients. Translocations between IGH and MAF may arise only in the absence of close proximity to the more frequent partners, as appears to be the case for individuals who develop t(14;16) MM. © 2013 Wiley Periodicals, Inc.
Potential consequences of healthcare recommendations: A focus on the U.S. Preventive Services Task Force
Authors: Satoskar Rohit , Reau Nancy
Published: March 2013

Healthcare guidelines and recommendations have broad-reaching impact. They serve as the evidence to enforce medical testing by establishing a bar for standard of care through their intrinsic credibility but also by affecting reimbursement. In this article, we discuss the various organizations in the United States that develop healthcare policy and guidelines. We focus on the recent recommendations for hepatitis C virus (HCV) screening put forward by these agencies and the potential effect of these documents. Additional discussion is provided on the recent draft HCV screening recommendations provided by the United States Preventive Services Task Force (USPSTF), comparison of these to the Centers for Disease Control and Prevention (CDC) guidelines, and professional societies' response to these. Conclusion: As written, the USPSTF recommendations may reduce physician adoption of HCV screening in the 1945-1965 birth cohort as advocated by the CDC. Conflicting guidelines may further confuse providers and the public. This will ultimately hinder recognition of chronic HCV in an otherwise easily identifiable, high prevalence group, allowing progression of disease at a time when therapeutic advances make cure a realistic opportunity for many. (HEPATOLOGY 2013 )
Short‐term environmental enrichment, in the absence of exercise, improves memory, and increases NGF concentration, early neuronal survival, and synaptogenesis in the dentate gyrus in a time‐dependent manner
Authors: Birch Amy M. , McGarry Niamh B. , Kelly Áine M.
Published: March 2013

Environmental manipulations can enhance neuroplasticity in the brain, with enrichment‐induced cognitive improvements being linked to increased expression of growth factors, such as neurotrophins, and enhanced hippocampal neurogenesis. There is, however, a great deal of variation in environmental enrichment protocols used in the literature, making it difficult to assess the role of particular aspects of enrichment upon memory and the underlying associated mechanisms. This study sought to evaluate the efficacy of environmental enrichment, in the absence of exercise, as a cognitive enhancer and assess the role of Nerve Growth Factor (NGF), neurogenesis and synaptogenesis in this process. We report that rats housed in an enriched environment for 3 and 6 weeks (wk) displayed improved recognition memory, while rats enriched for 6 wk also displayed improved spatial and working memory. Neurochemical analyses revealed significant increases in NGF concentration and subgranular progenitor cell survival (as measured by BrdU+ nuclei) in the dentate gyrus of rats enriched for 6 wk, suggesting that these cellular changes may mediate the enrichment‐induced memory improvements. Further analysis revealed a significant positive correlation between recognition task performance and BrdU+ nuclei. In addition, rats enriched for 6 wk showed a significant increase in expression of synaptophysin and synapsin I in the dentate gyrus, indicating that environmental enrichment can increase synaptogenesis. These data indicate a time‐dependent cognitive‐enhancing effect of environmental enrichment that is independent of physical activity. These data also support a role for increased concentration of NGF in dentate gyrus, synaptogenesis, and neurogenesis in mediating this effect. © 2013 Wiley Periodicals, Inc.
Counseling and Guided Self‐Help Outcomes for Clients With Bulimia Nervosa: A Meta‐Analysis of Clinical Trials From 1980 to 2010
Authors: Erford Bradley T. , Richards Taryn , Peacock Elizabeth , Voith Karen , McGair Heather , Muller Brooke , Duncan Kelly , Chang Catherine Y.
Published: March 2013

This meta‐analysis included 111 clinical trials exploring the effectiveness of counseling/psychotherapy and guided self‐help approaches in the treatment of bulimia nervosa. In general, single‐group studies supported higher efficacy of counseling/psychotherapy, whereas wait‐list, treatment‐as‐usual, and placebo studies indicated both approaches were equally effective at termination (posttest) and follow‐up in altering binging, purging, laxative use, and self‐reported bulimia or body dissatisfaction perceptions in nearly all comparisons.
Jane E. Myers: The Evolution of an Advocate
Authors: Nichols Lindsey M. , Carney JoLynn V.
Published: March 2013

This profile highlights Jane E. Myers's journey to becoming a leader in the counseling profession through her roles as a rehabilitation counselor, counselor educator, supervisor, mentor, and advocate. Her legacy is explored through her narrative of the evolution of her distinguished career, from early pivotal childhood experiences to her current professional passions. No matter how well the reader knows Dr. Myers, the authors believe that additional insight will be gained about this inspiring woman through this profile.
International students' experiences of integrating into the workforce
Authors: Nunes Sarah , Arthur Nancy
Published: March 2013

This study explored the integration experiences of 16 international students entering the Canadian workforce using a semistructured interview and constant comparison method. The international students were pursuing immigration to Canada, despite unmet job prospects. Students recommended that employers refrain from discriminating against students because of their international status and recognize the value of a diverse labor force. Students recommended that career services personnel help students build networks and employment contacts through pregraduation work experience. Incoming international students were advised to educate themselves about cultural norms for social and work interactions, research potential job opportunities, and create a professional network prior to degree completion.
Borderline Personality Features and Harmful Dysregulated Behavior: The Mediational Effect of Mindfulness
Authors: Wupperman Peggilee , Fickling Melissa , Klemanski David H. , Berking Matthias , Whitman Jeannie B.
Published: March 2013

Objectives

The current preliminary study investigated whether deficits in mindfulness (awareness, attentiveness, and acceptance of the present experience) may underlie the relationship of borderline personality disorder (BPD) features to self‐injury and overall acts of harmful dysregulated behavior.

Method

Nonparametric bootstrapping procedures were used to examine theoretical relationships among variables in a psychiatric sample of adults (N = 70). Participants were asked to imagine themselves in distress‐inducing situations and then write what they would actually do to decrease distress in such situations.

Results

As hypothesized, mindfulness statistically mediated the relationship of BPD features to reported acts of (a) self‐injury and (b) overall harmful dysregulated behaviors.

Conclusions

Difficulties in the ability to be aware, attentive, and accepting of ongoing experience may play a role in the relationship of BPD features to harmful dysregulated behaviors. Future research should clarify potential reciprocal effects between BPD features and mindfulness with prospective, multioccasion designs.
Recent Advances Using Immunomodulators for Inflammatory Bowel Disease
Authors: Nielsen Ole Haagen , Bjerrum Jacob Tveiten , Herfarth Hans , Rogler Gerhard
Published: March 2013

Use of the immunomodulators thiopurines and methotrexate (MTX) in the treatment of inflammatory bowel disease (IBD), i.e., Crohn's disease and ulcerative colitis (UC), is considered to be good clinical practice. However, despite being administered to a considerable number of IBD patients over the years, questions remain about the most rational treatment regimens of azathioprine (AZA), 6‐mercaptopurine (6‐MP), and MTX, and results from a range of recent studies necessitate increased attention to how to optimize the use of these immunomodulators. First and foremost, it is of utmost importance to define the subgroup of IBD patients in need of immunomodulators, including those in need of combination therapy with biologic agents, especially because some side effects may be rather severe. Second, colorectal cancer is observed more often in IBD patients than in the background population. However, a recent nationwide Dutch study pointed to a preventive effect of thiopurines. Finally, the need for an appropriate approach to the discontinuation of immunomodulators is emphasized. Since controversy continues regarding the most appropriate use of immunomodulators, this paper is focusing on pharmacokinetics, pharmacogenetics, and therapeutic blood testing, as well as the occurrence of adverse events, when using AZA, 6‐MP, and MTX in an attempt to determine a more up‐to‐date and rational treatment regimen in IBD.
Xylitol fermentation using hemicellulose hydrolysate prepared by acid pre‐impregnated steam explosion of corncob
Authors: Wang Le , Fan Xiaoguang , Tang Pingwah , Yuan Qipeng
Published: March 2013

BACKGROUND

Steam explosion is widely used on a variety of plant biomass for the hydrolysis of hemicellulose. However, hydrolysis by steam explosion suffers from low xylose yield, long hydrolysis time and high energy consumption, which impede the xylitol fermentation step. This study used a dilute sulfuric acid pre‐impregnation prior to the steam explosion to prepare corncob hemicellulose hydrolysate which offers high xylose yield for xylitol fermentation by Candida tropicalis.

RESULTS

After pre‐impregnation with 0.3% (wt) dilute sulfuric acid at a liquid to corncob ratio of 3 for 6 h, corncobs were steamed at 200 °C for 5 min to obtain a maximum xylose yield of 23.5% in the hydrolysate. The hydrolysate was detoxified by concentrating with vacuum evaporation followed by adsorption using activated carbon. The detoxified hydrolysate was then used for xylitol fermentation. Maximum xylitol yield of 75.1%, volumetric productivity of 2.01 g L‐1 h and biomass of 20.9 g L‐1 were obtained from the detoxified hydrolysate.

CONCLUSION

Findings suggested that this acid pre‐impregnated steam explosion strategy provides a highly effective way to prepare hemicellulose hydrolysate with high xylose yield, and could be potentially applied to industrial xylitol fermentation. © 2013 Society of Chemical Industry
In vitro ischemia suppresses hypoxic induction of hypoxia‐inducible factor‐1α by inhibition of synthesis and not enhanced degradation
Authors: Karuppagounder Saravanan S. , Basso Manuela , Sleiman Sama F. , Ma Thong C. , Speer Rachel E. , Smirnova Natalya A. , Gazaryan Irina G. , Ratan Rajiv R.
Published: March 2013

Hypoxia‐inducible factor (HIF) mediates a broad, conserved adaptive response to hypoxia, and the HIF pathway is a potential therapeutic target in cerebral ischemia. This study investigated the mechanism by which in vitro ischemia (oxygen‐glucose deprivation; OGD) affects canonical hypoxic HIF‐1α stabilization. We validated the use of a reporter containing the oxygen‐dependent degradation domain of HIF‐1α fused to firefly luciferase (ODD‐luc) to monitor quantitatively distinct biochemical events leading to hypoxic HIF‐1α expression or stabilization in a human neuroblastoma cell line (SH‐SY5Y). When OGD was imposed following a 2‐hr hypoxic stabilization of ODD‐luc, the levels of the reporter were reduced, consistent with prior models proposing that OGD enhances HIF prolylhydroxylase (PHD) activity. Surprisingly, PHD inhibitors and proteasome inhibitors do not stabilize ODD‐luc in OGD. Furthermore, OGD does not affect the half‐life of ODD‐luc protein following hypoxia, suggesting that OGD abrogates hypoxic HIF‐1α induction by reducing HIF‐1α synthesis rather than by enhancing its degradation. We observed ATP depletion under OGD vs. hypoxia and propose that ATP depletion enhances translational suppression, overcoming the selective synthesis of HIF concurrent with global decreases in protein synthesis in hypoxia. Taken together, these findings biochemically characterize a practical reporter for monitoring HIF‐1α levels and support a novel model for HIF regulation in an in vitro model of human ischemia. © 2013 Wiley Periodicals, Inc.
Effects of anthropogenic intermixing on the genetic structure of Dybowski's frog populations in northeast China
Authors: Zhang Ming , Wang Weisheng , Xu Yanchun , Jia Xueyuan , Zheng Xin , Ma Jianzhang
Published: March 2013

The Dybowski's frog (Rana dybowskii) is mainly distributed in northeast China and the Russian Far East. Its dried oviduct, or frog oil, has been used in traditional Chinese medicine for thousands of years. Frogs from different geographic regions exhibit variations in their body mass and oil productivity. As a result, farmers usually import high quality breeding stock from different areas to increase oviduct productivity. This practice could alter the genetic structure of the frog populations. We used 10 microsatellite loci to investigate the level of genetic variation for 10 frog populations in the context of human‐mediated disturbance. The study populations comprised the following: the Hebei, Tieli, and Jiamusi populations from the Lesser Khingan Mountains; the Mudanjiang, Jilin, Jiaohe, and Huadian populations from the north central Changbai Mountains; and the Tonghua, Benxi, and Xiuyan populations from the southern Changbai Mountains. Our results showed that the 3 Lesser Khingan Mountain populations exhibited highly significant differentiation values (FST = 0.047–0.071, P < 0.001). In addition, the Tonghua population differentiated significantly from the other 6 populations of the Changbai Mountains (P < 0.001). The genetic differentiation coefficient (FST) and gene flow (Nem) estimates showed that the Benxi and Jiaohe populations had a high degree of genetic similarity despite being geographically separated by mountains and river systems. We obtained similar results for the Xiuyan and Tieli populations. Furthermore, the degree of gene flow between the Jiamusi and the north central Changbai Mountain populations was greater than that observed between the Jiamusi and the other Lesser Khingan Mountain populations. These results therefore suggest that the Benxi, Xiuyan, and Jiamusi populations have undergone substantial intermixing because of human‐mediated relocation. Economic demands make completely stopping the geographical relocation of Dybowski's frog in northeast China virtually impossible. Consequently, effective management strategies are now a high priority to ensure that conservationists and local economies can work together to guarantee the long‐term survival of this species. © 2013 The Wildlife Society.
Harvest mortality in North American mallards: A reply to Sedinger and Herzog
Authors: Pöysä Hannu , Dessborn Lisa , Elmberg Johan , Gunnarsson Gunnar , Nummi Petri , Sjöberg Kjell , Suhonen Sari , Söderquist Pär
Published: March 2013

Sedinger and Herzog (2012) evaluated the evidence for the impact harvest mortality may have on North American duck populations. While doing that, they questioned our review (Pöysä et al. 2004) and conclusion that harvest mortality in North American mallards (Anas platyrhynchos) may have shifted from compensatory to additive over the period from the 1960s to the 1980s. In this reply, we correct Sedinger and Herzog's misrepresentations of our 2004 paper and argue that our interpretations of the results published at that time have not been invalidated. © 2013 The Wildlife Society.
Parenchymal alterations in cirrhotic livers in patients with hepatopulmonary syndrome or portopulmonary hypertension
Authors: Ma Changqing , Crippin Jeffrey S. , Chapman William C. , Korenblat Kevin , Vachharajani Neeta , Gunter Kristen L. , Brunt Elizabeth M.
Published: March 2013

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPH) are distinct pulmonary vascular complications of cirrhosis. Little is known about possible associated hepatic histopathological features. Explanted livers from patients clinically diagnosed with HPS (n = 8) or PPH (n = 7) and cirrhotic explants from controls (n = 30) without HPS or PPH were evaluated with trichrome histochemistry, anti–glutamine synthetase (anti-GS), and anti-CD34 immunohistochemistry (IHC). Trichrome stains were characterized by cirrhotic nodules (CNs) of various sizes, including incomplete septal cirrhosis (ISC). ISC was overrepresented in the HPS (4/8 or 50%) and PPH livers (3/7 or 43%); in addition, neither group had micronodular cirrhosis. The control explants showed the entire spectrum of nodules: micronodular, macronodular, mixed CNs, and ISC (P = 0.04). The variability of cirrhosis severity was shown with the Laennec grading system (0-6). The cirrhosis of the majority of the HPS (6/8) and PPH livers (6/7) was scored as mild, whereas the control explants were more evenly distributed across the mild (14/30) and moderate/severe grades (16/30). GS positivity was retained in a perivenular location as the dominant pattern in each explant group. CD34 staining detected capillarized sinusoids of CNs as well as vascular channels within septa, but no significant differences were found between the groups. None of the observed light microscopy or histochemistry and IHC patterns showed a correlation with the underlying liver disease. Although our results demonstrate variable architectural and vascular remodeling within and between explant livers regardless of the presence or types of pulmonary complications, there were differences in explants with HPS or PPH versus controls that correlated with less severe cirrhosis. Liver Transpl 19:741–750, 2013. © 2013 AASLD.
Kinetic Modeling from Early Product Development to Polymerization Process Optimization
Authors: Tracht Ursula , Richter Frank U.
Published: March 2013

Summary: This contribution illustrates how kinetic modeling supports early product development stages under industrial constraints also for smaller scale products. Diisocyanate oligomerization is selected as an example. Data for model parameterization and validation are acquired in kinetic experiments with on‐line IR monitoring. Based on these measured data and a proposed reaction scheme for the cyclo‐oligomerization of diisocyanates with equal reactivity of both isocyanate groups, two kinetic models differing in level of detail are developed. All experimental trends are described correctly with these kinetic models. A functional group based model is used for parameterization and prediction of conversion profiles. This model version is also applied for assessing working hypotheses on the details of the catalytic cycle and for developing strategies for catalyst and process optimization. A second model takes into account full molecular weight distribution and thus enables prediction of individual oligomer concentrations. Fast assessment of process alternatives is possible with both models.
Comprehensive Characterization of Chain End Groups of Vinylidene Fluoride Based Polymers
Authors: Albano Margherita , Barchiesi Emma , Biancardi Roberto , Dossi Marco , Geniram Giuliana , Vaccarono Paola
Published: March 2013

Summary: In this work an investigation of the chain end groups produced in the free radical copolymerization of vinilydene fluoride (VDF) and hexafluoropropylene (HFP) is performed. Type and amount of chain end groups are evaluated by a meticulous analytical characterization of VDF/HFP copolymer. At first pulsed gradient spin‐echo nuclear magnetic resonance (spin‐echo NMR) is used to identify all the chain end groups also at very low concentration (equal to 0.1 mmol · Kg−1). The instrument sensitivity is increased of an order of magnitude in comparison with the traditional NMR. Moreover potentiometric titration and ion chromatography (IC) are also used to study the chain end groups and, as a consequence, the nature and the amount of the acidity showed by the polymer chains. In details two intensity of acidity are detected by potentiometric titration, namely strong and weak. The strong acidity is associated to the presence of residual surfactant and can be removed washing the polymer, while the weak acidity is due to free molecules of fluoride acid (HF). The standard ion chromatography facility is properly modified to quantify the fluoride in the polymer matrix without any pre extraction in water. Thanks to this the HF concentration in the polymer is evaluated with high accuracy. A detailed kinetic scheme for the VDF/HFP polymerization is also proposed taking into account all the findings obtained studying the chain end groups.
The Effect of Polymer Microstructure and Thermal Post‐Treatment on Latex‐Based Pressure Sensitive Adhesive Performance
Authors: Dubé Marc A. , Qie Lili
Published: March 2013

Summary: Butyl acrylate/acrylic acid/2‐hydroxyl methacrylate (BA/AA/HEMA, weight ratio: 96/2/2) latexes were produced via starved seeded semi‐batch emulsion polymerization. The microstructure of the latex polymers was controlled by varying the amount of chain transfer agent (1‐dodecanethiol). The latexes were characterized for gel content, Mc (molecular weight between two adjacent cross‐linking points), Mw (molecular weight of sol polymers) and Me (molecular weight between entanglements). From these latexes, PSA films were cast, dried, conditioned and then thermally post‐treated at 120 °C to react the carboxyl and hydroxyl groups from the AA and HEMA units. Tack, peel strength and shear strength of the PSA films were then measured. The thermal post‐treatment was shown to be an effective way to improve latex‐based PSA performance. The effectiveness of the post‐treatment was observed to depend on the polymer microstructure (Mc relative to Me relative to Mw) of the untreated latex‐based PSAs and on the gel content.
Coupling Deterministic and Stochastic Simulation to Model the Polymeric Microstructure of LDPE
Authors: Neuhaus Eric , Busch Markus , Gonioukh Andrei , Herrmann Thomas , Lilge Dieter , Mannebach Gerd , Vittorias Iakovos
Published: March 2013

Summary:Simulation based process development of new LDPE grades often requires a deep insight into the exact microstructure of individual macromolecules. Therefore, we developed an approach, which combines the advantages of the deterministic (low computational time and high accuracy) and stochastic simulation (individual macromolecules with distinct microstructure). The approach can be used for the modeling of continuously driven autoclave and tubular reactors. First results visualize the random conformation of a distinct macromolecule as well as the resulting contraction factor.
Modeling Free Radical Ethylene Polymerization with Multifunctional Comonomers in Tubular Reactors: Influence on Microstructural LDPE Properties
Authors: Kadel Isabel , Herrmann Thomas , Busch Markus
Published: March 2013

Summary: A kinetic model is developed to predict the effect of multi‐functional comonomers in the high‐pressure polymerization of ethylene in industrial tubular reactors. Two different modified acrylate based comonomers were tested in the simulation for their influence on molecular‐weight distribution and branching densities. A comparison of both methods shows their potential to be used in an industrial process.
Cytotoxicity of PMMA‐Based Nanoparticles Synthesized Adopting SDS and Tween 80
Authors: Colombo Claudio , Lupi Monica , Ubezio Paolo , Moscatelli Davide
Published: March 2013

Summary: in this work the cytotoxicity of PMMA‐based nanoparticles against mouse mammary cancer cells (4T1) has been investigated. NPs have been synthesized using either monomer starved semi‐batch emulsion polymerization (MSSEP) or standard batch emulsion polymerization (BEP) processes adopting potassium persulfate (KPS) as initiator and two different emulsifiers: sodium dodecyl sulfate (SDS) and Tween 80. The toxicity of NPs produced using SDS has been confirmed in in vitro experiments while it has been found that NPs stabilized with Tween 80 show a good biocompatibility. Moreover, the absence of toxicity of NPs in which the SDS is substituted with Tween 80 adopting ion exchange resins (IER) has been proved. Finally the biocompatibility of the sulfate chain end groups coming from the adopted initiator has been assessed.
Modeling Crosslinking Polymerization in Batch and Continuous Reactors
Authors: Kryven Ivan , Berkenbos Arjen , Melo Priamo , Kim Dong‐Min , Iedema Piet D.
Published: March 2013

A new pseudo‐distribution approach is applied to the modeling of crosslinking copolymerization of vinyl and divinyl monomer and compared to Monte Carlo (MC) simulations. With the number of free pending double bonds as the main distribution variable, a rigorous solution of the three leading moments of the molecular size distribution becomes possible. Validation takes place with data of methyl methacrylate with ethylene glycol dimethacrylate. Well within the sol regime perfect agreement is found, but near the gelpoint larger discrepancies do appear. This is probably due to the existence of multiradicals that are not taken into account in the population balance approaches.

magnified image
Analysis of an exact algorithm for the vessel speed optimization problem
Authors: Hvattum Lars Magnus , Norstad Inge , Fagerholt Kjetil , Laporte Gilbert
Published: March 2013

Increased fuel costs together with environmental concerns have led shipping companies to consider the optimization of vessel speeds. Given a fixed sequence of port calls, each with a time window, and fuel cost as a convex function of vessel speed, we show that optimal speeds can be found in quadratic time. © 2013 Wiley Periodicals, Inc. NETWORKS, 2013
Kinetic and equilibrium modeling for adsorption of textile dyes in aqueous solutions by carboxymethyl cellulose/poly(acrylamide‐co‐hydroxyethyl methacrylate) semi‐interpenetrating network hydrogel
Authors: Bhattacharyya Ruma , Ray Samit Kumar
Published: March 2013

Semi‐interpenetrating network (IPN) hydrogels were synthesized by free radical copolymerization of acrylamide (AM) and hydroxyethyl methacrylate (HEMA) in aqueous solution of sodium carboxy methyl cellulose (CMC). The hydrogels were crosslinked with N,N′‐methylene bisacrylamide (NMBA). Hydrogel was also synthesized from copolymerisation of AM and HEMA. This was designated as PAMHEMA. All of these hydrogels were characterized by Fourier transforms infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X‐ray diffraction (XRD), mechanical properties, and equilibrium swelling in deionized water. These hydrogels were used for adsorption of two important textile dyes, i.e., basic fuchsin and methyl violet from water at different experimental conditions. These hydrogels were found to show high removal% and adsorption of these two dyes from water for both low and high feed concentration range. Experimental dye adsorption data were fitted to five kinetic and seven adsorption model equations with non‐linear fittings. The experimental data were observed to fit well to most of these model equations because of non‐linear fitting. POLYM. ENG. SCI., 53:2439–2453, 2013. ©2013 Society of Plastics Engineers
Label‐free quantitative analysis of the membrane proteome of Bace1 protease knock‐out zebrafish brains
Authors: Hogl Sebastian , van Bebber Frauke , Dislich Bastian , Kuhn Peer‐Hendrik , Haass Christian , Schmid Bettina , Lichtenthaler Stefan F.
Published: March 2013

The aspartyl protease BACE1 cleaves neuregulin 1 and is involved in myelination and is a candidate drug target for Alzheimer's disease, where it acts as the β‐secretase cleaving the amyloid precursor protein. However, little is known about other substrates in vivo. Here, we provide a proteomic workflow for BACE1 substrate identification from whole brains, combining filter‐aided sample preparation, strong‐anion exchange fractionation, and label‐free quantification. We used bace1‐deficient zebrafish and quantified differences in protein levels between wild‐type and bace1 −/− zebrafish brains. Over 4500 proteins were identified with at least two unique peptides and quantified in both wild‐type and bace1 −/− zebrafish brains. The majority of zebrafish membrane proteins did not show altered protein levels, indicating that Bace1 has a restricted substrate specificity. Twenty‐four membrane proteins accumulated in the bace1 −/− brains and thus represent candidate Bace1 substrates. They include several known BACE1 substrates, such as the zebrafish homologs of amyloid precursor protein and the cell adhesion protein L1, which validate the proteomic workflow. Additionally, several candidate substrates with a function in neurite outgrowth and axon guidance, such as plexin A3 and glypican‐1 were identified, pointing to a function of Bace1 in neurodevelopment. Taken together, our study provides the first proteomic analysis of knock‐out zebrafish tissue and demonstrates that combining gene knock‐out models in zebrafish with quantitative proteomics is a powerful approach to address biomedical questions.
A mass weighted chemical elastic network model elucidates closed form domain motions in proteins
Authors: Kim Min Hyeok , Seo Sangjae , Jeong Jay Il , Kim Bum Joon , Liu Wing Kam , Lim Byeong Soo , Choi Jae Boong , Kim Moon Ki
Published: March 2013

An elastic network model (ENM), usually Cα coarse‐grained one, has been widely used to study protein dynamics as an alternative to classical molecular dynamics simulation. This simple approach dramatically saves the computational cost, but sometimes fails to describe a feasible conformational change due to unrealistically excessive spring connections. To overcome this limitation, we propose a mass‐weighted chemical elastic network model (MWCENM) in which the total mass of each residue is assumed to be concentrated on the representative alpha carbon atom and various stiffness values are precisely assigned according to the types of chemical interactions. We test MWCENM on several well‐known proteins of which both closed and open conformations are available as well as three α‐helix rich proteins. Their normal mode analysis reveals that MWCENM not only generates more plausible conformational changes, especially for closed forms of proteins, but also preserves protein secondary structures thus distinguishing MWCENM from traditional ENMs. In addition, MWCENM also reduces computational burden by using a more sparse stiffness matrix.
Bimolecular nature of boron trifluoride catalyzed glycosylation of a galactosyl donor: The role of the acceptor
Authors: Li Haichen , Qiao Yuanyuan
Published: March 2013

Density functional theory (DFT) computations disclose the mechanism of a crucial neighboring participation step in BF3 catalyzed stereoselective glycosylation of 1,2‐cyclopropaneacetylated galactosyl donor. Two tandem SN2 displacements comprise this step: first, the glycosyl acceptor attacks the BF3‐activated donor to break the donor's 1,2‐cyclopropane ring; then, the donor's 2‐acetyl oxygen substitutes the acceptor to accomplish the neighboring participation. A donor–acceptor hydrogen bond has been found to lower the overall activation free energy. This mechanism is preferred over a 2‐acetyl oxygen coface SN2 displacement mechanism, in which no glycosyl acceptor is involved. © 2013 Wiley Periodicals, Inc.
The thresholds for diameter 2 in random Cayley graphs
Authors: Christofides Demetres , Markström Klas
Published: March 2013

Given a group G, the model denotes the probability space of all Cayley graphs of G where each element of the generating set is chosen independently at random with probability p.

In this article we show that for any and any family of groups Gk of order nk for which , a graph with high probability has diameter at most 2 if and with high probability has diameter greater than 2 if .

We also provide examples of families of graphs which show that both of these results are best possible.

Of particular interest is that for some families of groups, the corresponding random Cayley graphs achieve Diameter 2 significantly faster than the Erdős‐Renyi random graphs. © 2014 Wiley Periodicals, Inc. Random Struct. Alg., 45, 218–235, 2014
Neue Technologie für die Hängebrücke über die Saar in Mettlach – Brückenfahrbahn aus Sandwich Plate System (SPS)
Authors: Stihl Thomas , Chassard Carsten , Feldmann Markus , Bild Stefan
Published: March 2013

Die 1951 gebaute Hängebrücke über die Saar in Mettlach musste wegen Schäden am Seiltragwerk und an der Verbundfahrbahntafel für Fahrzeuge über 12 t gesperrt werden. Damit die denkmalgeschützte innerstädtische Brücke den vorhandenen Verkehrsverhältnissen wieder gerecht wird, musste die Fahrbahn durch eine wesentlich leichtere Konstruktion ersetzt werden. Durch den Einbau einer Stahlleichtfahrbahn in SPS‐Bauweise ist es möglich, den Verkehr über die Brücke wieder ohne Beschränkungen freizugeben. Der Beitrag beschreibt die Vorteile der neuen Technologie der eingebauten Sandwich Plate‐Fahrbahn im Vergleich zu klassischen Bauweisen. Die Entscheidungsfindung zur Vergabe der Bauleistung sowie Inhalte der Zustimmung im Einzelfall werden aufgezeigt. Der Vorgang und die Besonderheiten beim Einsatz der in Deutschland noch nicht eingeführten Technologie werden dargestellt.

Der Weg des von der Baufirma vorgeschlagenen Konzeptes ist ein innovatives Beispiel für aktuelle Entwicklungen im Stahlbau. Das Konzept basiert auf der 2010 im kanadischen Edmonton durchgeführten Fahrbahnsanierung der Dawson Bridge, die 2012 mit dem Nachhaltigkeitspreis der CISC (Canadian Institute of Steel Construction) ausgezeichnet wurde. Für den Einsatz in Mettlach wurde der Entwurf weiterentwickelt, um den Regularien der DIN‐Fachberichte 101 und 103 mit den Ansprüchen an Ermüdung gerecht zu werden.

New technology for the suspension bridge near Mettlach, Germany – A Sandwich Plate System made bridge deck. The 1951‐built suspension bridge spanning the river Saar at Mettlach, Germany needed to be closed for vehicles more than 12 t because of defects in the cable structure and damage of the composite bridge deck. So that the preservation listed urban bridge will meet again the existing traffic conditions, the bridge deck had to be replaced and lightened. Through the installation of a light steel roadway in SPS design it is possible to allow the traffic over the bridge without restrictions again. The paper describes the advantages of the new technology built Sandwich Plate bridge deck compared to traditional construction methods. The decision to award the construction works and contents of the individual approval are presented. The procedure and features in the use of this technology not yet introduced in Germany are given.

The realization concept proposed by the construction company is an innovative example of current development in steel construction. The concept is based on the 2010 roadway rehabilitation of the Dawson Bridge in Canadian Edmonton which won the Sustainability Award 2012 of CISC. For application in Mettlach additional development was required to meet the regulations of the DIN Fb 101 and 103 in accordance to the standards of fatigue.
Zur Grenztragfähigkeit von Verbunddübeln mit Klothoidenform
Authors: Lorenc Wojciech , Kożuch Maciej , Seidl Günter
Published: March 2013

Verbunddübel sind ein robustes und wirtschaftliches Tragelement zur Einleitung von Schubkräften zwischen Beton in Stahl, dessen Tragverhalten in der letzten Zeit Thema verschiedener Forschungsprojekte ist. Ausgehend vom Stand der Technik werden Untersuchungen zur plastischen Tragfähigkeit des Stahldübels erläutert. Neben Versuchen zur Stahldübeltragfähigkeit werden auch neue numerische Modelle vorgestellt und ein erweiterter Bemessungsansatz bewertet.

The ultimate load bearing capacity of composite dowels with clothoid form. Composite dowels are acting as a ductile and economic member to transfer shear forces from concrete to steel. Their load bearing behavior is highlighted in recent research projects. To complete the state‐of‐the‐art investigations in the plastic load bearing behavior of the steel dowel are presented. Beside experimental tests new numerical models of composite dowels will be discussed and a design recommendation will be validated.
Schrägseilbrücke mit Litzenbündelseilen: Elbebrücke Schönebeck – Konstruktion und Ausführung (Teil 1)
Authors: Brand Werner , Puls Joachim , Langer Stephan
Published: March 2013

Am 01. 11. 2012 wurde das letzte Stahlsegment des Stromfeldes der neuen Elbebrücke Schönebeck erfolgreich eingehoben. Mit einer Länge von 1128,5 m stellt das Bauwerk im Zuge der Ortsumgehung Schönebeck, B246a, eine der längsten und anspruchsvollsten Brückenbauwerke Sachsen‐Anhalts dar. Kernstück der neuen Elbquerung ist eine einhüftige Schrägseilbrücke mit der Hauptspannweite von 185 m. Der vorliegende Aufsatz behandelt die Konstruktion und Ausführung der Schrägseilbrücke.

A cable‐stayed bridge with parallel strand cables: Elbe Bridge Schönebeck (Germany) – construction and execution (part 1). On the first of November was the last steel segment of the main span of the new bridge over the Elbe near Schönebeck successfully lifted. The new bridge has a total length of 1128.50 m and a mainspan of 185 m built as a single tower cable‐stayed Bridge.
Hierarchical approaches for systems modeling in cardiac development
Authors: Gould Russell A. , Aboulmouna Lina M. , Varner Jeffrey D. , Butcher Jonathan T.
Published: March 2013

Ordered cardiac morphogenesis and function are essential for all vertebrate life. The heart begins as a simple contractile tube, but quickly grows and morphs into a multichambered pumping organ complete with valves, while maintaining regulation of blood flow and nutrient distribution. Though not identical, cardiac morphogenesis shares many molecular and morphological processes across vertebrate species. Quantitative data across multiple time and length scales have been gathered through decades of reductionist single variable analyses. These range from detailed molecular signaling pathways at the cellular levels to cardiac function at the tissue/organ levels. However, none of these components act in true isolation from others, and each, in turn, exhibits short‐ and long‐range effects in both time and space. With the absence of a gene, entire signaling cascades and genetic profiles may be shifted, resulting in complex feedback mechanisms. Also taking into account local microenvironmental changes throughout development, it is apparent that a systems level approach is an essential resource to accelerate information generation concerning the functional relationships across multiple length scales (molecular data vs physiological function) and structural development. In this review, we discuss relevant in vivo and in vitro experimental approaches, compare different computational frameworks for systems modeling, and the latest information about systems modeling of cardiac development. Finally, we conclude with some important future directions for cardiac systems modeling. WIREs Syst Biol Med 2013, 5:289–305. doi: 10.1002/wsbm.1217

This article is categorized under:

Models of Systems Properties and Processes > Cellular Models

Developmental Biology > Developmental Processes in Health and Disease

Biological Mechanisms > Regulatory Biology
Raman Spectroscopic Study of Rare Earth Chlorides in Alkali Chloride Eutectic Melts
Authors: Uda Takeshi , Fujii Toshiyuki , Iwadate Yasuhiko , Uehara Akihiro , Yamana Hajimu
Published: March 2013

Raman spectra of rare earth (REE: rare earth elements) trichloride (REE = Y, La, Ce, Pr, Sm, Gd, Dy, or Yb) dissolved in alkali chloride eutectic melts (LiCl‐KCl, LiCl‐RbCl, and LiCl‐CsCl) were measured at 793 K. The spectra showed polarized peaks centered around 240–270 cm–1, which were identified as the totally symmetric stretching vibration (ν1) of the octahedral REECl63–. The ν1 frequency increased with the polarizing power of the trivalent REE ions. The change in the ν1 frequency was found to be larger for lighter lanthanides. This was attributable to the distortion of the Oh symmetry of REECl63–.
Syntheses, Crystal Structures, and Magnetic Properties of Three Metal‐Nitroxide Complexes with the V‐shaped 4, 4′‐Oxybis(benzoate)
Authors: Chen Yi‐Wen , Li Hong‐Dao , Gao Dong‐Zhao , Wang Xiu‐Guang , Liu Zhong‐Yi , Sun Ya‐Qiu , Zhang Guo‐Ying , Xu Yan‐Yan
Published: March 2013

Three new metal–nitroxide complexes {[Ni(NIT4Py)2(obb)(H2O)2]·1.5H2O}n (1), {[Co(NIT4Py)2(obb)(H2O)2]·2H2O}n (2), and [Co(IM4Py)2(obb)2(H2O)2][Co(IM4Py)2(H2O)4]·10H2O (3) with the V‐shaped 4,4′‐oxybis(benzoate) [NIT4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, IM4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxide, and obb = 4, 4′‐oxybis(benzoate) anion] were synthesized and structurally characterized. Single‐crystal X‐ray analyses indicate that complexes 1 and 2 crystallize in neutral one‐dimensional (1D) zigzag chains, in which the nitroxide–metal–nitroxide units are linked by the V‐shaped 4,4′‐oxybis(benzoate) anions, whereas complex 3 consists of isolated mononuclear [Co(IM4Py)2(obb)2(H2O)2]2– anions and [Co(IM4Py)2(H2O)4]2+ ions. Magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the metal ions and the nitroxides.
String constraints on discrete symmetries in MSSM type II quivers
Authors: Anastasopoulos Pascal , Cvetič Mirjam , Richter Robert , Vaudrevange Patrick K. S.
Published: March 2013

Abstract

We study the presence of discrete gauge symmetries in D-brane semi-realistic compactifications. After establishing the constraints on the transformation behaviour of the chiral matter for the presence of a discrete gauge symmetry we perform a systematic search for discrete gauge symmetries within local semi-realistic D-brane realizations, based on four D-brane stacks, of the MSSM and the MSSM with three right-handed neutrinos. The systematic search reveals that Proton hexality, a discrete symmetry which ensures the absence of R-parity violating terms as well as the absence of dangerous dimension 5 proton decay operators, is only rarely realized. Moreover, none of the semi-realistic local D-brane configurations exhibit any family dependent discrete gauge symmetry.