bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multidetector Thermal Field‐Flow Fractionation as a Novel Tool for the Microstructure Separation of Polyisoprene and Polybutadiene
Authors: Greyling Guilaume , Pasch Harald 
Published: September 2014

For the first time, it is demonstrated that thermal field‐flow fractionation (ThFFF) is an efficient tool for the fractionation of polyisoprene (PI) and polybutadiene (PB) with regard to molecular microstructure. ThFFF analysis of 1,4‐ and 3,4‐PI as well as 1,4‐ and 1,2‐PB samples in tetrahydrofuran (THF), THF/cyclohexane, and cyclohexane reveals that isomers of the same polymer family having similar molar masses exhibit different Soret coefficients depending on microstructure for each solvent. The separation according to microstructure is found to be based on the cooperative influence of the normal and the thermal diffusion coefficient. Of the three solvents, cyclohexane has the greatest influence on the fractionation of the isomers. In order to determine the distribution of isomeric structures in the PI and PB samples, the samples are fractionated by ThFFF in cyclohexane and subsequently analyzed by 1H NMR. The isomeric distributions determined from NMR data correlate well with ThFFF retention data of the samples and thus further highlight the unique fractionating capabilities of ThFFF. The interplay of the normal and thermal diffusion coefficients that are influenced by temperature and the mobile phase opens the way to highly selective fractionations without the drawbacks of column‐based separation methods.
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Identification and characterization of genes differentially expressed in X and Y sperm using suppression subtractive hybridization and cDNA microarray
Authors: Chen Xiaoli , Yue Yang , He Yanan , Zhu Huabin , Hao Haisheng , Zhao Xueming , Qin Tong , Wang Dong 
Published: September 2014

SUMMARYDifferential expression of genes leads to variations in the phenotypes of X and Y sperm, although some differentially expressed gene products are shared through intercellular bridges. Genes differentially expressed in bovine X and Y sperm were identified by a combination of suppression subtractive hybridization (SSH), cDNA microarray, and sequence‐homology analysis. Microarray data and Significance Analysis of Microarrays software were used to identify 31 differentially expressed genes, only four of which were previously identified. These genes are involved in fundamental life processes of mature sperm, and may be associated with the differences between X and Y sperm since 27 versus 4 were upregulated in X versus Y sperm, respectively. The levels of expression of seven genes—including the known genes UTY, DPH3, CYTB, and ISCU, and the unknown genes X + Y contig 41, X + Y contig 18, and Y + X contig 16—were validated by quantitative real‐time PCR, and some genes were clearly differentially expressed by X and Y sperm, despite the presence of intercellular bridges among spermatids. These results provide a theoretical basis for research on gene expression during sperm development, as well as on sex control at the level of sperm. Mol. Reprod. Dev. 81: 908–917, 2014. © 2014 Wiley Periodicals, Inc.
Simultaneous exposure to MRI‐related static and low‐frequency movement‐induced time‐varying magnetic fields affects neurocognitive performance: A double‐blind randomized crossover study
Authors: van Nierop Lotte E. , Slottje Pauline , van Zandvoort Martine , Kromhout Hans 
Published: September 2014

PurposeThis experimental study aims to separate neurocognitive effects resulting from exposure to static magnetic stray fields (SMF) alone and the combination of SMF and low‐frequency movement‐induced time‐varying magnetic fields (TVMF) using a 7 Tesla (T) MRI scanner in stand‐by mode.MethodsIn a double‐blind randomized crossover experiment, 36 healthy volunteers underwent four sessions, two exposed conditions, and two corresponding sham conditions. The exposure conditions were in front of the scanner bore and consisted of 1.0 T SMF with or without 2.4 T/s TVMF, induced by standardized head movements before each of the five neurocognitive tasks. These specific tasks were selected because previous experiments showed negative effects of SMF + TVMF exposure on test performance.ResultsExposure to SMF in combination with TVMF decreased verbal memory performance significantly and changed visual acuity. Similarly, attention and concentration were negatively affected with borderline significance. Exposure to SMF only did not have significant effects on the performance on any of the tasks.ConclusionNeurocognitive effects were only observed when simultaneously exposed to SMF and TVMF from a 7 T MRI scanner. Therefore, exposure to TVMF seems essential in eliciting the neurocognitive effects in our present study and, presumably, previous experiments. Magn Reson Med 74:840–849, 2015. © 2014 Wiley Periodicals, Inc.
In vitro study to simulate the intracardiac magnetohydrodynamic effect
Authors: Buchenberg Waltraud B. , Mader Wolfgang , Hoppe Georg , Lorenz Ramona , Menza Marius , Büchert Martin , Timmer Jens , Jung Bernd 
Published: September 2014

PurposeBlood flow causes induced voltages via the magnetohydrodynamic (MHD) effect distorting electrograms (EGMs) made during magnetic resonance imaging. To investigate the MHD effect in this context MHD voltages occurring inside the human heart were simulated in an in vitro model system inside a 1.5 T MR system.MethodsThe model was developed to produce MHD signals similar to those produced by intracardiac flow and to acquire them using standard clinical equipment. Additionally, a new approach to estimate MHD distortions on intracardiac electrograms is proposed based on the analytical calculation of the MHD signal from MR phase contrast data.ResultsThe recorded MHD signals were similar in magnitude to intracardiac signals that would be measured by an electrogram of the left ventricle. The dependency of MHD signals on magnetic field strength and electrode separation was well reflected by an analytical model. MHD signals reconstructed from MR flow data were in excellent agreement with the MHD signal measured by clinical equipment.ConclusionThe in vitro model allows investigation of MHD effects on intracardiac electrograms. A phase contrast MR scan was successfully applied to characterize and estimate the MHD distortion on intracardiac signals allowing correction of these effects. Magn Reson Med 74:850–857, 2015. © 2014 Wiley Periodicals, Inc.
Maternal Behavior and Infant Physiology During Feeding in Premature and Term Infants Over the First Year of Life
Authors: Weber Ashley M. , Harrison Tondi M. 
Published: September 2014

AbstractLittle is known about the relationship between maternal behavior and the stability of premature infants' physiologic responses during feeding. In a secondary data analysis, we examined relationships between quality of maternal behavior and cardiorespiratory physiology during feeding in 61 premature and 53 term infants at four times over the first year of life. Measures included heart rate (HR), respiratory rate (RR), and oxygen saturation; Child Feeding Skills Checklist; and Parent‐Child Early Relational Assessment. Birthweight, gestational age, and neurodevelopmental risk were covariates. Quality of maternal behavior did not predict infants' physiologic response to feeding. However, birthweight was related to infant feeding physiology among all infants over the first year of life. Stress during fetal life, which may lead to impaired intrauterine growth and low birthweight, may have longitudinal effects on cardiorespiratory functioning of premature infants. Research is needed to further investigate the biological pathways by which maternal–infant interaction supports behavioral and physiologic feeding outcomes of premature infants. © 2014 Wiley Periodicals, Inc.
Empirical valence bond simulations of the hydride transfer step in the monoamine oxidase B catalyzed metabolism of dopamine
Authors: Repič Matej , Vianello Robert , Purg Miha , Duarte Fernanda , Bauer Paul , Kamerlin Shina C. L. , Mavri Janez 
Published: September 2014

ABSTRACTMonoamine oxidases (MAOs) A and B are flavoenzymes responsible for the metabolism of biogenic amines such as dopamine, serotonin and noradrenaline. In this work, we present a comprehensive study of the rate‐limiting step of dopamine degradation by MAO B, which consists in the hydride transfer from the methylene group of the substrate to the flavin moiety of the FAD prosthetic group. This article builds on our previous quantum chemical study of the same reaction using a cluster model (Vianello et al., Eur J Org Chem 2012; 7057), but now considering the full dimensionality of the hydrated enzyme with extensive configurational sampling. We show that MAO B is specifically tuned to catalyze the hydride transfer step from the substrate to the flavin moiety of the FAD prosthetic group and that it lowers the activation barrier by 12.3 kcal mol−1 compared to the same reaction in aqueous solution, a rate enhancement of more than nine orders of magnitude. Taking into account the deprotonation of the substrate prior to the hydride transfer reaction, the activation barrier in the enzyme is calculated to be 16.1 kcal mol−1, in excellent agreement with the experimental value of 16.5 kcal mol−1. Additionally, we demonstrate that the protonation state of the active site residue Lys296 does not have an influence on the hydride transfer reaction. Proteins 2014; 82:3347–3355. © 2014 Wiley Periodicals, Inc.
Polyanion binding accelerates the formation of stable and low‐toxic aggregates of ALS‐linked SOD1 mutant A4V
Authors: Zhao Dan , Zhang Shibing , Meng Yan , Xiongwei Dong , Zhang Dan , Liang Yi , Wang Li , Liu Changlin 
Published: September 2014

ABSTRACTThe toxic property thus far shared by both ALS‐linked SOD1 variants and wild‐type SOD1 is an increased propensity to aggregation. However, whether SOD1 oligomers or aggregates are toxic to cells remains to be well defined. Moreover, how the toxic SOD1 species are removed from intra‐ and extracellular environments also needs to be further explored. The DNA binding has been shown to be capable of accelerating the aggregatio\n of wild‐type and oxidized SOD1 forms under acidic and neutral conditions. In this study, we explore the binding of DNA and heparin, two types of essential life polyanions, to A4V, an ALS‐linked SOD1 mutant, under acidic conditions, and its consequences. The polyanion binding alters the A4V conformation, neutralizes its local positive charges, and increases its local concentrations along the polyanion chain, which are sufficient to lead to acceleration of the pH‐dependent A4V aggregation. The accelerated aggregation, which is ascribed to the polyanion binding‐mediated removal or shortening of the lag phase in aggregation, contributes to the formation of amorphous A4V nanoparticles. The prolonged incubation with polyanions not only results in the complete conversion of likely soluble toxic A4V oligomers into non‐ and low‐toxic SDS‐resistant aggregates, but also increases their stability. Although this is only an initial step toward reducing the toxicity of SOD1 mutants, the accelerating role of polyanions in protein aggregation might become one of the rapid pathways that remove toxic forms of SOD1 mutants from intra‐ and extracellular environments. Proteins 2014; 82:3356–3372. © 2014 Wiley Periodicals, Inc.
Hints for the metallic phase in Rb4C60 under pressure
Authors: Francis E. A. , Kuntscher C. A. 
Published: September 2014

The alkali fulleride Rb4C60 was investigated by infrared spectroscopy under high pressure, to study the vibrational and electronic excitations. The material exhibits a bad metal behavior in the measured pressure range (0.8–8 GPa). With increasing pressure the Drude term in the far‐infrared region increases, which signals an increasing metallic character. By following the optical excitations under pressure, we could attribute the underlying mechanism of the pressure‐induced insulator‐to‐metal transition in Rb4C60 to the closing of the charge gap, and the nanoscale phase separation scenario discussed in the literature seems to be unlikely.
p‐Times differentiable unbounded functions for robust control of uncertain switched nonlinear systems with tracking constraints
Authors: Niu Ben , Zhao Xudong , Zhang Lixian , Li Hongyi 
Published: September 2014

SummaryThis paper investigates the problem of robust controller design for output‐constrained and state‐constrained uncertain switched nonlinear systems. By using the idea of p‐times differentiable unbounded functions and the backstepping technique, a constructive method is proposed to design effective controllers such that the output of a class of uncertain switched nonlinear systems in lower triangular form can asymptotically track a constant reference signal without violation of the output tracking error constraint. Furthermore, the explored method is applied to the state‐constrained robust stabilization problem for a class of general uncertain switched nonlinear systems. Finally, a simulation example is provided to demonstrate the effectiveness of the developed results. Copyright © 2014 John Wiley & Sons, Ltd.
Water ethics on a human‐dominated planet: rationality, context and values in global governance
Authors: Schmidt Jeremy J. , Peppard Christiana Z. 
Published: September 2014

A discourse on water ethics has emerged as a field linking practical water demands, social practices, and hydrological constraints to philosophic norms. The field arose parallel to growing, global understandings of the interconnected nature of water management and governance challenges. As such, it has been inflected with issues and contests across a range of policy concerns—from holistic and integrated water management to economics, justice, and human rights. The emerging water ethics discourse challenges both traditional environmental ethics and conventional approaches to resource management on issues of gender, power relations, and ecological concerns. It suggests an alternate, place‐specific approach for linking shared water concerns to normative contests.WIREs Water2014, 1:533–547. doi: 10.1002/wat2.1043This article is categorized under:Human Water > Rights to WaterHuman Water > Value of WaterHuman Water > Water Governance
The Significance of Atrial Fibrillation in Patients Aged ≥55 years Undergoing Abdominal Surgery
Authors: Kazaure Hadiza S. , Roman Sanziana A. , Tyler Douglas , Sosa Julie A. 
Published: September 2014

AbstractBackgroundThe Institute of Medicine has identified atrial fibrillation (AF) among national priorities for research. We examine the incidence of AF and its association with outcomes of patients undergoing abdominal surgery.MethodsPatients ≥55 years who underwent abdominal surgery captured in a State Inpatient Database, 2008–2010. Three patient groups were created: (1) No diagnosis of AF (No‐AF), (2) Pre‐existing AF (Hx‐AF), and (3) New‐onset AF (New‐AF). Outcomes were analysed using bivariate and multivariate methods.ResultsAF incidence among 116,477 patients was 8.6 %; approximately one in four patients aged ≥85 years had AF. 26.6 % of patients with AF experienced New‐AF; the latter was more likely after pancreas resection (43.0 %) and least common after cholecystectomy (20.2 %). Complications (71.1, 47.3 vs. 26.5 %), mortality (8.0, 5.7 vs. 2.0 %), longer hospital stays (8.8, 5.6 vs. 3.8 days), and higher hospitalization cost ($41,427, $26,312 vs. $18,310) were more likely in patients with AF (New‐AF, Hx‐AF vs. No‐AF respectively) (all p < 0.001). After adjustment, New‐AF was among factors independently associated with mortality (OR 2.0, 95 % CI 1.7–2.4, p < 0.001); each case of New‐AF increased cost of care by $4,482. Factors independently associated with New‐AF included ≥1 complication, electrolyte imbalance, and procedure‐type. Whereas 2.0 % of patients who developed New‐AF were admitted from a long‐term care facility, 23.8 % of patients with New‐AF were discharged to a long‐term care facility.ConclusionsAF is common among abdominal surgery patients, particularly the elderly; New‐AF is a serious, potentially avoidable adverse event that could serve as an important quality of care indicator for abdominal surgery patients.
Transforming Individual Civic Engagement into Community Collective Efficacy: The Role of Bonding Social Capital
Authors: Collins Charles R. , Neal Jennifer Watling , Neal Zachary P. 
Published: September 2014

AbstractCollective efficacy is defined as residents’ perceived collective capacity to take coordinated and interdependent action on issues that affect their lives. This study explored factors associated with neighborhood collective efficacy among residents. Utilizing a national sample of 4,120 urban households provided by Annie E. Casey Foundation's Making Connection Initiative, we investigated the mediating role of residents’ perceptions of bonding social capital (i.e. reciprocity, trust, and shared norms) in the association between civic engagement and collective efficacy. Multiple regression analyses revealed that civic engagement and bonding social capital were both directly related to collective efficacy. Additionally, bonding social capital partially mediated the relationship between civic engagement and collective efficacy. Specifically, residents who reported greater levels of civic engagement also reported higher levels of bonding social capital. In turn, residents who reported higher levels of bonding social capital also reported higher levels of neighborhood collective efficacy. We discuss implications of these findings for researchers and practitioners interested in associations of neighborhood collective efficacy.
Mitochondrial disease associated with complex I (NADH‐CoQ oxidoreductase) deficiency
Authors: Scheffler Immo E. 
Published: September 2014

AbstractMitochondrial diseases due to a reduced capacity for oxidative phosphorylation were first identified more than 20 years ago, and their incidence is now recognized to be quite significant. In a large proportion of cases the problem can be traced to a complex I (NADH‐CoQ oxidoreductase) deficiency (Phenotype MIM #252010). Because the complex consists of 44 subunits, there are many potential targets for pathogenic mutations, both on the nuclear and mitochondrial genomes. Surprisingly, however, almost half of the complex I deficiencies are due to defects in as yet unidentified genes that encode proteins other than the structural proteins of the complex. This review attempts to summarize what we know about the molecular basis of complex I deficiencies: mutations in the known structural genes, and mutations in an increasing number of genes encoding “assembly factors”, that is, proteins required for the biogenesis of a functional complex I that are not found in the final complex I. More such genes must be identified before definitive genetic counselling can be applied in all cases of affected families.
Biomechanical Evaluation of Metacarpal Fracture Fixation: Application of a 90° Internal Fixation Model
Authors: Watt Andrew J. , Ching Randal P. , Huang Jerry I. 
Published: September 2014

Purpose Complications in metacarpal fracture treatment increase in proportion to the severity of the initial injury and the invasiveness of the surgical fixation technique. This manuscript evaluates the feasibility of minimizing internal fixation construct size and soft tissue dissection, while preserving the advantages of stable internal fixation in a biomechanical model. We hypothesized that comparable construct stability could be achieved with mini-plates in an orthogonal (90/90) configuration compared with a standard dorsal plating technique. Methods This hypothesis was evaluated in a transverse metacarpal fracture model. Twelve metacarpals were subject to either placement of a 2.0-mm six-hole dorsal plate or two 1.5-mm four-hole mini-plates in a 90/90 configuration. These constructs were tested to failure in a three-point bending apparatus, attaining failure force, displacement, and stiffness. Results Mean failure force was 353.5±121.1 N for the dorsal plating construct and 358.8±77.1 N for the orthogonal construct. Mean failure displacement was 3.3±1.2 mm for the dorsal plating construct and 4.1±0.9 mm for the orthogonal construct. Mean stiffness was 161.3±50.0 N/mm for the dorsal plating construct and 122.1±46.6 N/mm for the orthogonal construct. Mean failure moment was 3.09±1.06 Nm for the dorsal plating construct and 3.14±0.67 Nm for the orthogonal construct. The dorsal plating group failed via screw pullout, whereas the orthogonal failed either by screw pullout or breakage of the plate. Conclusions When subject to apex dorsal bending, the orthogonal construct and the standard dorsal plate construct behaved comparably. These data suggest that despite its shorter length, lower profile, and less substantial screws, the orthogonal construct provides sufficient rigidity. Clinical Relevance This study represents a “proof of concept” regarding the applicability of orthogonal plating in the metacarpal and provides the foundation for minimizing construct size and profile.
Effectiveness of Coping Strategies at Alleviating Cue-Induced Craving: a Pilot Study
Authors: Dicker Michelle , Frandsen Mai , Palmer Matthew A. , Ferguson Stuart G. 
Published: September 2014

Introduction:Results from observational studies suggest that smoking-related cues play a role in triggering relapse. Coping strategies are among the most commonly used cessation strategies, but little is known about how they aid quitting.Aims:The aim of this pilot study was to evaluate the effect of a suite of selected coping techniques on alleviating cue-induced cravings.Methods:Thirty-seven daily smokers (Intervention: 20; Control: 17) participated in two laboratory cue-reactivity sessions, separated by approximately one week, during which craving was assessed before and after exposure to smoking-related cues. Following the first session, participants in the Intervention Group were taught a suite of coping strategies. During the second session, participants in the Intervention Group were encouraged to use these strategies.Results:Participants in the Intervention Group reported a slight decrease in craving following the acute exposure manipulation at the second session, compared to an increase in craving among participants in the Control Group. Intervention Group participants also reported a decrease in craving following prolonged exposure to the smoking cues (compared to an increase in craving among Control Group participants). In both cases, the difference between groups was more pronounced among smokers who responded to the cue-reactivity manipulation. The observed differences were not significant.Conclusions:The results of this pilot study suggest that coping techniques may be beneficial in alleviating both the initial spike in craving observed following acute cue exposure, and aid recovery during prolonged exposure. These findings need to be replicated in a larger study.