bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Developments in Cyclic Polymers: Synthesis, Applications, and Perspectives
Authors: Zhu Yinghuai , Hosmane Narayan S. 
Published: May 2015

AbstractDue to the topological effect, cyclic polymers demonstrate different and unique physical and biological properties in comparison with linear counterparts having the same molecular‐weight range. With advanced synthetic and analytic technologies, cyclic polymers with different topologies, e.g. multicyclic polymers, have been reported and well characterized. For example, various cyclic DNA and related structures, such as cyclic duplexes, have been prepared conveniently by click chemistry. These types of DNA have increased resistance to enzymatic degradation and have high thermodynamic stability, and thus, have potential therapeutic applications. In addition, cyclic polymers have also been used to prepare organic–inorganic hybrids for applications in catalysis, e.g. catalyst supports. Due to developments in synthetic technology, highly pure cyclic polymers could now be produced in large scale. Therefore, we anticipate discovering more applications in the near future. Despite their promise, cyclic polymers are still less explored than linear polymers like polyolefins and polycarbonates, which are widely used in daily life. Some critical issues, including controlling the molecular weight and finding suitable applications, remain big challenges in the cyclic‐polymer field. This review briefly summarizes the commonly used synthetic methodologies and focuses more on the attractive functional materials and their biological properties and potential applications.
Molecular dynamics study on folding and allostery in RfaH
Authors: Xiong Liqin , Liu Zhenxing 
Published: May 2015

ABSTRACTUpon being released from the N‐terminal domain (NTD), the C‐terminal domain (CTD) switches from α‐helix conformation to β‐barrel conformation, which converts RfaH from a transcription factor into an activator of translation. The
conformational change may be viewed as allosteric transition. We use molecular dynamics simulations of coarse‐grained off‐lattice model to study the thermal folding of NTD, CTD, RfaH and the allosteric transition in CTD. The melting temperatures from the specific heat profiles indicate that the β‐barrel conformation is much more stable than the α‐helix conformation. Two helices in α‐helix conformation have similar thermodynamic stabilities and the melting temperatures for β sheets show slight dispersion. Under the interaction with NTD, CTD is greatly stabilized and the cooperativity for thermal folding is also significantly improved. The
allosteric transition can be approximately described by a two‐state model and three parallel pathways are identified. The transition state ensemble, quantified by a Tanford β‐like parameter, resembles the α‐helix and β‐barrel conformations almost to the same extent. Proteins 2015; 83:1582–1592. © 2015 Wiley Periodicals, Inc.
Topological surface states of infinitely adaptive series (BiSe)(Bi): A first‐principles study
Authors: Zhang JunJie , Liu Xia , Huang GuiQin 
Published: May 2015

AbstractThe surface electron structures of infinitely adaptive series (BiSe)(Bi) films with various thicknesses and different terminated terraces are calculated from density‐functional theory by including spin–orbit coupling. Our calculations show that the evolution of the surface states from hybridization gaps for thin films to robust topological surface states for thicker films. However, the topological surface states show different Kramers point energies and dispersions for different terminations and different ratio of m:n, suggesting that the topological surface state in infinitely adaptive series (BiSe)(Bi) can be tuned by changing the ratio of m:n or by changing termination.
Serial clustering of extratropical cyclones in a multi‐model ensemble of historical and future simulations
Authors: Economou T. , Stephenson D. B. , Pinto J. G. , Shaffrey L. C. , Zappa G. 
Published: May 2015

This study has investigated serial (temporal) clustering of extratropical cyclones simulated by 17 climate models participating in CMIP5. Clustering was estimated by calculating the dispersion (ratio of variance to mean) of 30 December–February counts of Atlantic storm tracks passing near each grid point. Results from single historical simulations of 1975–2005 were compared to those from historical ERA40 reanalyses from 1958 to 2001 and single future model projections of 2069–2099 under the RCP4.5 climate change scenario.Models were generally able to capture the broad features in reanalyses reported previously: underdispersion/regularity (i.e. variance less than mean) in the western core of the Atlantic storm track surrounded by overdispersion/clustering (i.e. variance greater than mean) to the north and south and over Western Europe. Regression of counts onto North Atlantic Oscillation (NAO) indices revealed that much of the overdispersion in the historical reanalyses and model simulations can be accounted for by NAO variability.Future changes in dispersion were generally found to be small and not consistent across models. The overdispersion statistic, for any 30‐year sample, is prone to large amounts of sampling uncertainty which obscures the climate change signal. For example, the projected increase in dispersion for storm counts near London in the CNRMCM5 model is 0.1 compared to a standard deviation of 0.25. Projected changes in the mean and variance of NAO are insufficient to create changes in overdispersion that are discernible above natural sampling variations.
The Effects of Improved Water Quality on Fish Assemblages in a Heavily Modified Large River System
Authors: Parker J. , Epifanio J. , Casper A. , Cao Y. 
Published: May 2015

AbstractA long history of human alterations has affected the hydrology, physical habitat and water quality of most large river ecosystems. For more than a century, the Illinois River Waterway has been subject to channelization, damming, dredging, agricultural runoff and industrial and municipal effluents. This study evaluates how subsequent improvements in water quality have influenced long‐term changes in fish assemblages (1983–2010). We used five metrics to characterize the changes in fish assemblages. These metrics depicted shifts in the abundance and biomass of predatory and native fishes and species richness. Random forests (RF) and multiple linear regressions (MLRs) were used to relate the fish metrics to individual water quality and weather variables, with weather primarily used to account for inter‐annual variation. Model performances varied spatially and among fish metrics (0 ≤ pseudo‐R2 ≤ 0.73 for RF; 0.10 ≤ adjR2 ≤ 0.88 for MLR), but dissolved oxygen, un‐ionized ammonia and water clarity were often the best predictors. As the distance downstream of major pollutant sources increased, water quality became less important for explaining the changes in fish metrics and weather more important. These results indicate that water quality improvement largely accounts for fish assemblage recovery in the river system, although within some reaches we examined, weather had substantial compounding effects. The results could be used to prioritize water quality variables for long‐term monitoring and aid in predicting fish assemblage responses to future changes in water quality and climate. Copyright © 2015 John Wiley & Sons, Ltd.
Numerical Modelling of Braided Rivers with Structure‐from‐Motion‐Derived Terrain Models
Authors: Javernick L. , Hicks D. M. , Measures R. , Caruso B. , Brasington J. 
Published: May 2015

AbstractThe development of three‐dimensional reconstructions of channel morphology has historically been limited by the high costs of geospatial data collection and software modelling. Advances in image processing, sensor technology and portable remote‐sensing platforms, however, now offer the opportunity to derive survey quality terrain models at significantly reduced cost and without traditional deployment and logistical constraints. There is a pressing need to establish whether new geospatial technologies such as structure‐from‐motion photogrammetry can be used to deliver topographic data products that are suitable for higher‐dimensional hydrodynamic modelling. To address this question, we evaluate the results of simulations using Delft3D that were designed to model distributed, depth‐averaged flows in a wide, shallow, gravel‐bed braided river. The topography for these simulations was derived from digital elevation models (DEMs) generated using structure‐from‐motion and optical bathymetric mapping of two linked reaches of the Ahuriri River, New Zealand. The DEM quality achieved vertical surface errors of 0.10 m in non‐vegetated areas and 0.20 m in inundated areas. Simulations with 1.5 m and 2.5 m resolution grids for low‐flow, medium‐flow and high‐flow conditions were calibrated and tested against field real‐time kinematic‐global navigation satellite system observations. Results revealed that modelled depth errors were comparable to the DEM uncertainty, while simulated and observed inundation patterns achieve a maximum of 81% agreement. Given the complexity of the braided network and shallow flow depths, these simulations provide a powerful demonstration of the suitability of these terrain models for hydrodynamic applications. Copyright © 2015 John Wiley & Sons, Ltd.
How exploitation impedes and impels exploration: Theory and evidence
Authors: Piao Ming , Zajac Edward J. 
Published: May 2015

Research summary: This study suggests that strategy and organizational scholars seeking to analyze the impact of exploitation on exploration would benefit by moving away from the generally assumed unitary perspective on exploitation. Specifically, we propose a multifaceted perspective on exploitation by theoretically and empirically distinguishing between repetitive exploitation versus incremental exploitation. We argue that repetitive exploitation can impede exploration and delay firms' responses to environmental changes, while incremental exploitation can impel exploration and accelerate firms' responses to environmental changes. We test our arguments using extensive longitudinal data from the hard disk drive (HDD) industry, and our supportive empirical findings highlight the relevance of our distinction between the two types of exploitation and their very different effects on exploration.Managerial summary: This study offers a solution to the puzzle of why many believe firms cannot excel at advancing existing practices and developing new initiatives, typically described as the trade‐off between exploitation and exploration. We introduce the distinction between repetitive and incremental exploitation and show that only the former type of innovation generates rigidity toward exploration, whereas the latter actually promotes exploration. More specifically, our evidence from the hard disk drive industry shows that those firms emphasizing incremental innovation (as opposed to repetition of their existing practices) were most likely to remain explorative over time, whereas firms emphasizing more repetitive innovation proved less open to changes. We discuss the implications of our findings as suggesting that firms seeking to optimize their innovativeness over the long term should strive to remain active in incrementally innovating their existing practices. Copyright © 2015 John Wiley & Sons, Ltd.
Detection of fetal copy number variants by non‐invasive prenatal testing for common aneuploidies
Authors: Li R. , Wan J. , Zhang Y. , Fu F. , Ou Y. , Jing X. , Li J. , Li D. , Liao C. 
Published: May 2015

AbstractObjectiveTo evaluate the clinical performance of non‐invasive prenatal testing (NIPT) in detecting fetal copy number variants (CNVs).MethodsNIPT of cell‐free fetal DNA was performed retrospectively, using stored maternal plasma, at an average gestational age of 21.1 weeks in 117 pregnant women who had previously undergone invasive prenatal testing for chromosome microarray analysis (CMA). Among the fetal samples tested by CMA, 18 had positive results (CNVs > 1 megabase (Mb)) and 99 had negative results (CNVs < 1 Mb or without CNVs detected). The results of NIPT and CMA were then compared.ResultsIn the 11 CMA‐positive samples with CNVs > 5 Mb, the detection rate of CNVs was 90.9%; the one case missed by NIPT had a fetal fraction of 4.7%. For the other seven CMA‐positive samples with CNVs < 5 Mb, the detection rate was 14.3%; only one case with a 2.82‐Mb duplication was detected, with a fetal fraction of 26.7%. For 35.7% (5/14) of CNVs detected by both NIPT and CMA, the differences in fragment length were within ± 1 Mb. In this study, the overall sensitivity and specificity of NIPT for detecting CNVs > 1 Mb were 61.1% and 95.0%, respectively, with a false‐positive rate of 5.0%.ConclusionsOur results demonstrate that NIPT for common aneuploidies can detect fetal CNVs > 5 Mb with high sensitivity, provided that fetal fraction is high enough, without increasing sequencing depth. The detection power of NIPT is determined mostly by fetal fraction and CNV size. A positive NIPT screening result for CNVs must be interpreted with caution and validated by additional diagnostic study. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Does anemia–polycythemia complicating twin–twin transfusion syndrome affect outcome after fetoscopic laser surgery?
Authors: Donepudi R. , Papanna R. , Snowise S. , Johnson A. , Bebbington M. , Moise K. J. 
Published: May 2015

AbstractObjectiveTwin anemia–polycythemia sequence (TAPS) can occur as a unique disease or as a complication of twin–twin transfusion syndrome (TTTS). Middle cerebral artery (MCA) Doppler studies are not currently part of the routine evaluation of monochorionic twins since they are not used in the Quintero staging system. As such, the true incidence of TAPS is unknown. We aimed to compare the characteristics and outcomes of twin pregnancies with TTTS complicated by spontaneous anemia–polycythemia vs those with TTTS alone.MethodsThis was a secondary analysis of data collected prospectively from a cohort of 156 consecutive patients undergoing fetoscopic laser surgery for TTTS, between October 2011 and August 2014. TAPS was defined as discordance in the preoperative MCA peak systolic velocity (PSV), with one twin fetus having MCA‐PSV ≤ 1.0 multiples of the median (MoM) and the other having MCA‐PSV ≥ 1.5 MoM. Maternal demographics as well as preoperative, operative and postoperative variables were analyzed.ResultsIncluded in the final analysis were 133 patients with complete records: 11 cases with TTTS with anemia–polycythemia and 122 cases with TTTS alone. There was no difference in maternal body mass index, gestational age (GA) at procedure, rate of preterm prelabor rupture of membranes or GA at delivery between the two groups. Patients with TTTS and anemia–polycythemia were more likely to be older (P = 0.03) and parous (P = 0.04) and had a significantly lower number of placental anastomoses (P = 0.01). The dual live‐birth rate was similar for both groups (P = 0.76).ConclusionCases of TTTS with anemia–polycythemia were more likely to be found in parous and older women and were characterized by fewer vascular anastomoses. TTTS with anemia–polycythemia was not associated with worse perinatal outcome after laser therapy. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Clinical pattern, mutations and in vitro residual activity in 33 patients with severe 5, 10 methylenetetrahydrofolate reductase (MTHFR) deficiency
Authors: Huemer Martina , Mulder‐Bleile Regina , Burda Patricie , Froese D. Sean , Suormala Terttu , Zeev Bruria Ben , Chinnery Patrick F. , Dionisi‐Vici Carlo , Dobbelaere Dries , Gökcay Gülden , Demirkol Mübeccel , Häberle Johannes , Lossos Alexander , Mengel Eugen , Morris Andrew A. , Niezen‐Koning Klary E. , Plecko Barbara , Parini Rossella , Rokicki Dariusz , Schiff Manuel , Schimmel Mareike , Sewell Adrian C. , Sperl Wolfgang , Spiekerkoetter Ute , Steinmann Beat , Taddeucci Grazia , Trejo‐Gabriel‐Galán Jose M. , Trefz Friedrich , Tsuji Megumi , Vilaseca María Antònia , von Kleist‐Retzow Jürgen‐Christoph , Walker Valerie , Zeman Jiri , Baumgartner Matthias R. , Fowler Brian 
Published: May 2015

AbstractBackgroundSevere methylenetetrahydrofolate reductase (MTHFR) deficiency is a rare inborn defect disturbing the remethylation of homocysteine to methionine (<200 reported cases). This retrospective study evaluates clinical, biochemical genetic and in vitro enzymatic data in a cohort of 33 patients.MethodsClinical, biochemical and treatment data was obtained from physicians by using a questionnaire. MTHFR activity was measured in primary fibroblasts; genomic DNA was extracted from cultured fibroblasts.ResultsThirty‐three patients (mean age at follow‐up 11.4 years; four deceased; median age at first presentation 5 weeks; 17 females) were included. Patients with very low (<1.5 %) mean control values of enzyme activity (n = 14) presented earlier and with a pattern of feeding problems, encephalopathy, muscular hypotonia, neurocognitive impairment, apnoea, hydrocephalus, microcephaly and epilepsy. Patients with higher (>1.7–34.8 %) residual enzyme activity had mainly psychiatric symptoms, mental retardation, myelopathy, ataxia and spasticity. Treatment with various combinations of betaine, methionine, folate and cobalamin improved the biochemical and clinical phenotype. During the disease course, patients with very low enzyme activity showed a progression of feeding problems, neurological symptoms, mental retardation, and psychiatric disease while in patients with higher residual enzyme activity, myelopathy, ataxia and spasticity increased. All other symptoms remained stable or improved in both groups upon treatment as did brain imaging in some cases. No clear genotype‐phenotype correlation was obvious.DiscussionMTHFR deficiency is a severe disease primarily affecting the central nervous system. Age at presentation and clinical pattern are correlated with residual enzyme activity. Treatment alleviates biochemical abnormalities and clinical symptoms partially.
Redox signalling and mitochondrial stress responses; lessons from inborn errors of metabolism
Authors: Olsen Rikke K. J. , Cornelius Nanna , Gregersen Niels 
Published: May 2015

AbstractMitochondria play a key role in overall cell physiology and health by integrating cellular metabolism with cellular defense and repair mechanisms in response to physiological or environmental changes or stresses. In fact, dysregulation of mitochondrial stress responses and its consequences in the form of oxidative stress, has been linked to a wide variety of diseases including inborn errors of metabolism. In this review we will summarize how the functional state of mitochondria — and especially the concentration of reactive oxygen species (ROS), produced in connection with the respiratory chain — regulates cellular stress responses by redox regulation of nuclear gene networks involved in repair systems to maintain cellular homeostasis and health. Based on our own and other's studies we re‐introduce the ROS triangle model and discuss how inborn errors of mitochondrial metabolism, by production of pathological amounts of ROS, may cause disturbed redox signalling and induce chronic cell stress with non‐resolving or compromised cell repair responses and increased susceptibility to cell stress induced cell death. We suggest that this model may have important implications for those inborn errors of metabolism, where mitochondrial dysfunction plays a major role, as it allows the explanation of oxidative stress, metabolic reprogramming and altered signalling growth pathways that have been reported in many of the diseases. It is our hope that the model may facilitate novel ideas and directions that can be tested experimentally and used in the design of future new approaches for pre‐symptomatic diagnosis and prognosis and perhaps more effective treatments of inborn errors of metabolism.
Identification of quantitative trait loci for yield and yield related traits in groundnut (Arachis hypogaea L.) under different water regimes in Niger and Senegal
Authors: Faye Issa , Pandey Manish K. , Hamidou Falalou , Rathore Abhishek , Ndoye Ousmane , Vadez Vincent , Varshney Rajeev K. 
Published: May 2015

AbstractYield under drought stress is a highly complex trait with large influence to even a minor fluctuation in the environmental conditions. Genomics-assisted breeding holds great promise for improving such complex traits more efficiently in less time, but requires markers associated with the trait of interest. In this context, a recombinant inbred line mapping population (TAG 24 × ICGV 86031) was used to identify markers associated with quantitative trait loci (QTLs) for yield and yield related traits at two important locations of West Africa under well watered and water stress conditions. Among the traits analyzed under WS condition, the harvest index (HI) and the haulm yield (HYLD) were positively correlated with the pod yield (PYLD) and showed intermediate broad sense heritability. QTL analysis using phenotyping and genotyping data resulted in identification of 52 QTLs. These QTLs had low phenotypic variance (<12 %) for all the nine traits namely plant height, primary branching, SPAD chlorophyll meter reading, percentage of sound mature kernels, 100 kernel weight, shelling percentage, HI, HYLD and PYLD. Interestingly, few QTLs identified in this study were also overlapped with previously reported QTLs detected for drought tolerance related traits identified earlier in Indian environmental conditions using the same mapping population. Accumulating these many small-effect QTLs into a single genetic background is nearly impossible through marker-assisted backcrossing and even marker-assisted recurrent selection. Under such circumstances, the deployment of genomic selection is the most appropriate approach for improving such complex traits with more precision and in less time.
Cell surface engineering with polyelectrolyte-stabilized magnetic nanoparticles: A facile approach for fabrication of artificial multicellular tissue-mimicking clusters
Authors: Dzamukova Maria R. , Naumenko Ekaterina A. , Rozhina Elvira V. , Trifonov Alexander A. , Fakhrullin Rawil F. 
Published: May 2015

Abstract
Regenerative medicine requires new ways to assemble and manipulate cells for fabrication of tissue-like constructs. Here we report a novel approach for cell surface engineering of human cells using polymer-stabilized magnetic nanoparticles (MNPs). Cationic polyelectrolyte-coated MNPs are directly deposited onto cellular membranes, producing a mesoporous semi-permeable layer and rendering cells magnetically responsive. Deposition of MNPs can be completed within minutes, under cell-friendly conditions (room temperature and physiologic media). Microscopy (TEM, SEM, AFM, and enhanced dark-field imaging) revealed the intercalation of nanoparticles into the cellular microvilli network. A detailed viability investigation was performed and suggested that MNPs do not inhibit membrane integrity, enzymatic activity, adhesion, proliferation, or cytoskeleton formation, and do not induce apoptosis in either cancer or primary cells. Finally, magnetically functionalized cells were employed to fabricate viable layered planar (two-cell layers) cell sheets and 3D multicellular spheroids.