bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative characterization of kaolinite dispersibility in styrene–butadiene rubber composites by fractal dimension
Authors: Zhang Yude , Liu Qinfu , Frost Ray L.
Published: April 2014

A fractal method was introduced to quantitatively characterize the dispersibility of modified kaolinite (MK) and precipitated silica (PS) in styrene–butadiene rubber (SBR) matrix based on the lower magnification transmission electron microscopic images. The fractal dimension (FD) is greater, and the dispersion is worse. The fractal results showed that the dispersibility of MK in the latex blending sample is better than that in the mill blending samples. With the increase of kaolinite content, the FD increases from 1.713 to 1.800, and the dispersibility of kaolinite gradually decreases. There is a negative correlation between the dispersibility and loading content. With the decrease of MK and increase of PS, the FD significantly decreases from 1.735 to 1.496 and the dipersibility of kaolinite remarkably increases. The hybridization can improve the dispersibility of fillers in polymer matrix. The FD can be used to quantitatively characterize the aggregation and dispersion of kaolinite sheets in rubber matrix. POLYM. COMPOS., 36:1486–1493, 2015. © 2014 Society of Plastics Engineers
Synthesis of polyacrylamide hydrogels as p–n‐junction with ionic charge carriers
Authors: Alveroglu Esra , Yilmaz Yasar
Published: April 2014

Three different designs for p–n junctions were formed with p‐and n‐type polyacrylamide hydrogels (PAAm) doped with positive (Na+) and negative (Br−) ions as charge carriers. First, previously synthesized p‐and n‐type gels in slab forms were contacted physically with together. Second, having synthesized p‐type gel, n‐type pregel solution was poured onto p‐type slab gel for synthesis. Thus, p‐and n‐type gels were synthesized as to be contacted chemically together. Third, first p‐type and n‐type pregel solutions were mixed together, then the mixing was poured into a pot to form a layer, and then the reaction was performed under an electric field for directing the dopants on the opposite sides. The rectification efficiencies of all these junctions were discussed in detail. POLYM. ENG. SCI., 54:2799–2805, 2014. © 2013 Society of Plastics Engineers
Patterns of Antibacterial Use and Impact of Age, Race/Ethnicity, and Geographic Region on Antibacterial Use in an Outpatient Medicaid Cohort
Authors: Gahbauer Alice M. , Gonzales Marco L. , Guglielmo B. Joseph
Published: April 2014

Study Objectives

To describe patterns of outpatient antibacterial use among California Medicaid (Medi‐Cal) fee‐for‐service system beneficiaries, and to investigate the influence of demographic factors—age, race/ethnicity, state county, and population density—on those patterns.

Design

Retrospective analysis of administrative claims data.

Data Source

Medi‐Cal fee‐for‐service system claims database.

Patients

All outpatient Medi‐Cal fee‐for‐service system beneficiaries enrolled between 2006 and 2011 who had at least one systemic antibacterial claim.

Measurements and Main Results

Rates of antibacterial prescribing and the proportion of broad‐spectrum antibacterial use were measured over the study period and among age, racial/ethnic, and geographic (county) groups. Of the 10,018,066 systemic antibacterial claims selected for analysis, antibacterial prescribing rates decreased from 542 claims/1000 beneficiaries in 2006 to 461 claims/1000 beneficiaries in 2011 (r = −0.971, p=0.0012; τ‐b = −1.00, p=0.009). Among age groups, children had the highest rate of use (605 claims/1000 beneficiaries, χ2 (2) = 320,000, p<0.001); among racial/ethnic groups, Alaskan Natives and Native Americans had the highest rate of use (1086/1000 beneficiaries, χ2 (5) = 197,000, p<0.001). Broad‐spectrum antibacterial prescribing increased from 28.1% (95% confidence interval [CI] 28.1–28.2%) to 32.7% (95% CI 32.6–32.8%) over the study period. Senior age groups and whites received the highest proportions of broad‐spectrum agents (53.4% [95% CI 52.5–54.3%] and 36.6% [95% CI 36.6–36.7%], respectively). Population density was inversely related to both overall antibacterial use (ρ = −0.432, p=0.0018) and broad‐spectrum antibacterial prescribing (ρ = −0.359, p<0.001). The rate of prescribing decreased over the study period for all antibacterial classes with the exception of macrolides and sulfonamides. Amoxicillin was the most frequently prescribed agent.

Conclusion

Overall and broad‐spectrum antibacterial use in the Medi‐Cal fee‐for‐service program are less than that observed nationally. Significant variations in prescribing exist between age and racial/ethnic groups, and heavily populated areas are associated with both less antibacterial use and less broad‐spectrum antibacterial prescribing. Studies are needed to determine the reasons for the observed differences in antibacterial use among demographic groups.
Antibody‐Mediated Rejection in Kidney Transplantation: A Review of Pathophysiology, Diagnosis, and Treatment Options
Authors: Kim Miae , Martin Spencer T. , Townsend Keri R. , Gabardi Steven
Published: April 2014

Antibody‐mediated rejection (AMR), also known as B‐cell–mediated or humoral rejection, is a significant complication after kidney transplantation that carries a poor prognosis. Although fewer than 10% of kidney transplant patients experience AMR, as many as 30% of these patients experience graft loss as a consequence. Although AMR is mediated by antibodies against an allograft and results in histologic changes in allograft vasculature that differ from cellular rejection, it has not been recognized as a separate disease process until recently. With an improved understanding about the importance of the development of antibodies against allografts as well as complement activation, significant advances have occurred in the treatment of AMR. The standard of care for AMR includes plasmapheresis and intravenous immunoglobulin that remove and neutralize antibodies, respectively. Agents targeting B cells (rituximab and alemtuzumab), plasma cells (bortezomib), and the complement system (eculizumab) have also been used successfully to treat AMR in kidney transplant recipients. However, the high cost of these medications, their use for unlabeled indications, and a lack of prospective studies evaluating their efficacy and safety limit the routine use of these agents in the treatment of AMR in kidney transplant recipients.
Comparison of Acute Kidney Injury During Treatment with Vancomycin in Combination with Piperacillin‐Tazobactam or Cefepime
Authors: Gomes Diane M. , Smotherman Carmen , Birch Amy , Dupree Lori , Della Vecchia Bethany J. , Kraemer Dale F. , Jankowski Christopher A.
Published: April 2014

Study Objective

To evaluate the observed incidence of acute kidney injury (AKI) in adult patients receiving either piperacillin‐tazobactam and vancomycin or cefepime‐vancomycin for more than 48 hours.

Design

Retrospective matched cohort.

Setting

Large academic medical center.

Patients

Adult patients without preexisting renal dysfunction admitted over an 8‐month time period who received either the combination of piperacillin‐tazobactam and vancomycin or cefepime‐vancomycin for more than 48 hours were evaluated forAKI, defined by the Acute Kidney Injury Network criteria.

Measurements and Main Results

A total of 224 patients receiving either antimicrobial combination were evaluated forAKI. The incidence ofAKIwas significantly higher in the piperacillin‐tazobactam and vancomycin group (34.8%) compared with the cefepime‐vancomycin group (12.5%) in the unmatched analysis (p<0.0001). After adjusting for potential sources of bias through propensity score matched pairs and conditional logistic regression, piperacillin‐tazobactam and vancomycin combination therapy (p=0.003) was an independent predictor ofAKI. There were no significant differences in time toAKIor hospital length of stay between groups.

Conclusions

The results of this study suggest that there may be an association between piperacillin‐tazobactam and vancomycin combination therapy and increased incidence ofAKI.
Efficacy and Safety of Analgosedation with Fentanyl Compared with Traditional Sedation with Propofol
Authors: Tedders Kristen M. , McNorton Kelly N. , Edwin Stephanie B.
Published: April 2014

Objectives

To compare the efficacy and safety of analgosedation with fentanyl versus traditional sedation with propofol in critically ill patients receiving mechanical ventilation.

Methods

Retrospective, observational study evaluating adult critically ill patients on mechanical ventilation at a community teaching hospital who received continuous infusion fentanyl (n=50) or propofol (n=50) from September 2011–March 2013.

Results

Median duration of mechanical ventilation was similar between patients receiving propofol and fentanyl infusions (46.7 hr vs 46.0 hr, p=0.19). No difference was noted in median intensive care unit length of stay between groups (p=0.42). A larger percentage of patients receiving propofol required rescue opioids compared with patients receiving fentanyl (56% vs 34%, p=0.04). Furthermore, patients receiving propofol required significantly more rescue opioid therapy during the course of mechanical ventilation as calculated by fentanyl equivalents (150 μg vs 100 μg, p=0.03). No difference in the rate of intensive care unit delirium was noted between groups (fentanyl 23% vs propofol 27%, p=0.80).

Conclusion

Analgosedation with fentanyl appears to be a safe and effective strategy to facilitate mechanical ventilation. This regimen does not appear to affect duration of mechanical ventilation when compared with propofol, but may allow for more optimal pain management in critically ill patients.
The Need forPGY2‐Trained Clinical Pharmacy Specialists
Authors: Ragucci Kelly R. , O'Bryant Cindy L. , Campbell Kristin Bova , Buck Marcia L. , Dager William E. , Donovan Jennifer L. , Emerson Kayleigh , Gubbins Paul O. , Haight Robert J. , Jackevicius Cynthia , Murphy John E. , Prohaska Emily
Published: April 2014

The American College of Clinical Pharmacy and other stakeholder organizations seek to advance clinical pharmacist practitioners, educators, and researchers. Unfortunately, there remains an inadequate supply of residency‐trained clinical specialists to meet the needs of our health care system, and nonspecialists often are called on to fill open specialist positions. The impact of clinical pharmacy specialists on pharmacotherapy outcomes in both acute care and primary care settings demonstrates the value of these specialists. This commentary articulates the need for postgraduate year two (PGY2)‐trained clinical specialists within the health care system by discussing various clinical and policy rationales, interprofessional support, economic justifications, and their impact on quality of care and drug safety. The integrated practice model that has grown out of the American Society of Health‐System Pharmacists Pharmacy Practice Model Initiative (PPMI) could threaten the growth and development of future clinical specialists. Therefore, the ways in whichPGY2‐trained clinical pharmacist specialists are deployed in thePPMIrequire further consideration.PGY2 residencies provide education and training opportunities that cannot be achieved in traditional professional degree programs or postgraduate year one residencies. These specialists are needed to provide direct patient care to complex patient populations and to educate and train pharmacy students and postgraduate residents. Limitations to training and hiringPGY2‐trained clinical pharmacy specialists include site capacity limitations and lack of funding. A gap analysis is needed to define the extent of the mismatch between the demand for specialists by health care systems and educational institutions versus the capacity to train clinical pharmacists at the specialty level.
Halogeno‐modified polystyrene: monomer reactivity ratios, thermal behaviour and flammability
Authors: Wiacek Malgorzata , Wesolek Dorota , Rojewski Szymon , Bujnowicz Krzysztof , Schab‐Balcerzak Ewa
Published: April 2014

Chemical modification based on incorporation of flame retardants into polymer backbones was used in order to reduce flammability of polystyrene (PSt). The halogeno‐substituted styrenes: 4‐chlorostyrene (ClSt), 4‐bromostyrene (BrSt) and 2,3,4,5,6‐pentafluorostyrene (5FSt) were applied as reactive flame retardants. Homo‐ and copolymers of these halogeno‐substituted styrenes and styrene (St) were synthesized with various feed ratios using free radical bulk polymerization with azobisisobutyronitrile as a initiator. This yielded series of (co)polymers with various amounts of included ClSt, BrSt and 5FSt (5–50 mol% of modified St). Copolymer compositions were determined using 1H NMR spectroscopy. The relative reactivity ratios of the used comonomers were determined by applying conventional linearization methods. The Jaacks (J) method was used for systems including BrSt and ClSt monomers whereas the Fineman–Ross method was additionally used to confirm the values of reactivity ratios of St–5FSt. The reactivity ratios of comonomer pairs obtained from J plots were 0.75 and 0.38 (St–ClSt), 1.65 and 0.46 (St–BrSt), 0.44 and 0.42 (St–5FSt). Glass transition temperature and thermal stability of obtained (co)polymers were determined using differential scanning calorimetry and thermogravimetric analysis (TGA), respectively. The thermal degradation kinetic of PSt, PClSt, PBrSt and P5FSt was studied applying TGA. Kinetic parameters such as thermal decomposition activation energy (E) and frequency factor (A) were estimated using Ozawa and Kissinger models. The resulting activation energies estimated using these two methods were quite close. The values of activation energy (kJ mol−1) increased in the following order: PClSt (E(O) = 216.1) < PSt (E(O) = 219.9) < PBrSt (E(O) = 224.7) < P5FSt (E(O) = 330.9). A pyrolysis combustion flow calorimeter was applied as a tool for assessing the flammability of the synthesized (co)polymers. © 2014 Society of Chemical Industry
Insulin‐like growth factor 1 receptor signaling induced by supraphysiological doses of IGF‐1 in human peripheral blood lymphocytes
Authors: Spaziani Sara , Imperlini Esther , Mancini Annamaria , Caterino Marianna , Buono Pasqualina , Orrù Stefania
Published: April 2014

Insulin‐like growth factor‐1 (IGF‐1) mediates some of growth hormone anabolic functions through its receptor, IGF‐1R. Following ligand binding, intracellular signaling pathways are activated favouring proliferation, cell survival, tissue growth, development, and differentiation. IGF‐1 is included in the World Anti‐Doping Agency Prohibited List. While the evidence for IGF‐1 as performance‐enhancing substrate in healthy humans is still weak, clinical studies demonstrated that the endogenous growth hormone/IGF‐1 excess is associated with cardiovascular implications. Previously, we demonstrated that human peripheral blood lymphocytes represent a suitable system to identify a gene signature, related to dihydrotestosterone or IGF‐1 abuse, independent from the type of sport. In addition, in a proteomic study, we demonstrated that dihydrotestosterone hyperdosage affects cell motility and apoptosis. Here, we investigate the doping action of IGF‐1 by means of a differential proteomic approach and specific protein arrays, revealing an active cytoskeletal reorganization mediated by Stat‐1; moreover, IGF‐1 stimulation produces a sustained activation of different signaling pathways as well as an overproduction of cytokines positively related to immune response and inflammation. In conclusion, these data indicate that, following IGF‐1 hyperdosage, circulating peripheral blood lymphocytes could be more prone to transendothelial migration.
Binding of insecticidal lectin Colocasia esculenta tuber agglutinin (CEA) to midgut receptors of Bemisia tabaci and Lipaphis erysimi provides clues to its insecticidal potential
Authors: Roy Amit , Gupta Sumanti , Hess Daniel , Das Kali Pada , Das Sampa
Published: April 2014

The insecticidal potential of Galanthus nivalis agglutinin‐related lectins against hemipterans has been experimentally proven. However, the basis behind the toxicity of these lectins against hemipterans remains elusive. The present study elucidates the molecular basis behind insecticidal efficacy of Colocasia esculenta tuber agglutinin (CEA) against Bemisia tabaci and Lipaphis erysimi. Confocal microscopic analyses highlighted the binding of 25 kDa stable homodimeric lectin to insect midgut. Ligand blots followed by LC MS/MS analyses identified binding partners of CEA as vacuolar ATP synthase and sarcoplasmic endoplasmic reticulum type Ca2+ ATPase from B. tabaci, and ATP synthase, heat shock protein 70 and clathrin heavy chain assembly protein from L. erysimi. Internalization of CEA into hemolymph was confirmed by Western blotting. Glycoprotein nature of the receptors was identified through glycospecific staining. Deglycosylation assay indicated the interaction of CEA with its receptors to be probably glycan mediated. Surface plasmon resonance analysis revealed the interaction kinetics between ATP synthase of B. tabaci with CEA. Pathway prediction study based on Drosophila homologs suggested the interaction of CEA with insect receptors that probably led to disruption of cellular processes causing growth retardation and loss of fecundity of target insects. Thus, the present findings strengthen our current understanding of the entomotoxic potentiality of CEA, which will facilitate its future biotechnological applications.
Cellulose nanocrystals and related nanocomposites: Review of some properties and challenges
Authors: Mariano Marcos , El Kissi Nadia , Dufresne Alain
Published: April 2014

Cellulosic nanoparticles with high Young's modulus, crystallinity, specific surface area, and aspect ratio can be found in the natural structure of plant fibers. Indeed, lignocellulosic fibers consist of semicrystalline cellulose nanofibrils embedded in an amorphous matrix mainly composed of lignin and hemicelluloses. These nanostructures give the mechanical strength to higher plant cells, and are biodegradable, renewable, resistant, and widely available to produce nanocomposites with low density, and improved and controlled mechanical, optical, and barrier properties. Nanoparticles can be extracted from cellulose using a top‐down mechanically or chemically assisted deconstructing strategy, and owing to their highly reactive surface ensuing nanomaterials can be chemically modified to tailor their properties for a wide range of applications. This review is limited to cellulose chemically extracted nanocrystals and aims to provide an overview about several aspects that involve this material, including sources, properties, challenges, and perspectives. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 791–806
Enhancing the PLA crystallization rate by incorporating a polystyrene‐block‐poly(methyl methacrylate) block copolymer: Synergy of polystyrene and poly(methyl methacrylate) segments
Authors: Wu Chien‐Pang , Wang Cheng‐Chien , Chen Chuh‐Yung
Published: April 2014

A polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) exhibiting a well‐defined structure was prepared combining anionic polymerization and mercaptan/ε‐caprolactam living polymerization. To evaluate how this block copolymer affected the crystallization of polylactide (PLA), 0.5 wt % thiol‐terminated PS homopolymer (PSSH), PMMA, and PS‐b‐PMMA was melt‐blended with PLA. The calorimetric characterization of the nonisothermal and isothermal crystallization behavior was analyzed according to Avrami's theory, indicating that PS‐b‐PMMA more effectively increased the crystallization kinetics of the PLA matrix than did PSSH or PMMA. The results revealed that the synergistic effect of the PS and PMMA blocks appeared only when they were simultaneously presented in the PLA matrix. The PS block increased the number of nucleation sites and decreased the spherulite size, whereas the PMMA block facilitated the excellent dispersion of PS‐b‐PMMA in the PLA matrix as shown in polarizing optical microscope experiments. Incorporating PS‐b‐PMMA improved the PLA crystallization rate by promoting heterogeneous nucleation. In addition, incorporating 0.5 wt % PS‐b‐PMMA increased the relative crystallinity of PLA to 43.5%, and decreased the crystallization half‐time to 2.4 min when the blend was isothermal at 105 °C. The PLA crystal structure was unchanged by the presence of PS‐b‐PMMA; however, the crystallization rate was enhanced as probed by SEM and X‐ray diffraction. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 823–832
Formation of a polycrystalline film of donor material on PEDOT:PSS buffer induced by crystal nucleation
Authors: Harano Koji , Okada Satoshi , Furukawa Shunsuke , Tanaka Hideyuki , Nakamura Eiichi
Published: April 2014

Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most popular anode buffer coated on indium tin oxide. It is thought to improve the inorganic–organic contact, but little is known about its role in organic–organic contact. This study addresses the latter issue by examining how the PEDOT:PSS layer affects the crystallization process of the neighboring layer composed of p‐type organic semiconductors in an organic photovoltaic device. Low landing voltage scanning electron microscopic analysis of crystals and aggregates of two donor compounds, tetrabenzoporphyrin (BP) and poly(3‐hexylthiophene) (P3HT), showed that PEDOT:PSS effectively nucleates the crystallization or aggregation of the donor material on its surface to form a uniformly thick film of polycrystalline BP or aggregated P3HT molecules. By contrast, a graphitic surface cannot induce structural order of the donor molecules on it. This result implies that pinning of the donor molecules to the acidic PEDOT:PSS surface promotes the heterogeneous nucleation at the organic–organic interface. © 2014 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014, 52, 833–841
Crystal structure of the Campylobacter jejuni CmeC outer membrane channel
Authors: Su Chih‐Chia , Radhakrishnan Abhijith , Kumar Nitin , Long Feng , Bolla Jani Reddy , Lei Hsiang‐Ting , Delmar Jared A. , Do Sylvia V. , Chou Tsung‐Han , Rajashankar Kanagalaghatta R. , Zhang Qijing , Yu Edward W.
Published: April 2014

As one of the world's most prevalent enteric pathogens, Campylobacter jejuni is a major causative agent of human enterocolitis and is responsible for more than 400 million cases of diarrhea each year. The impact of this pathogen on children is of particular significance. Campylobacter has developed resistance to many antimicrobial agents via multidrug efflux machinery. The CmeABC tripartite multidrug efflux pump, belonging to the resistance‐nodulation‐cell division (RND) superfamily, plays a major role in drug resistant phenotypes of C. jejuni. This efflux complex spans the entire cell envelop of C. jejuni and mediates resistance to various antibiotics and toxic compounds. We here report the crystal structure of C. jejuni CmeC, the outer membrane component of the CmeABC tripartite multidrug efflux system. The structure reveals a possible mechanism for substrate export.
Structural evolution and membrane interactions of Alzheimer's amyloid‐beta peptide oligomers: New knowledge from single‐molecule fluorescence studies
Authors: Johnson Robin D. , Steel Duncan G. , Gafni Ari
Published: April 2014

Amyloid‐β peptide (Aβ) oligomers may represent the proximal neurotoxin in Alzheimer's disease. Single‐molecule microscopy (SMM) techniques have recently emerged as a method for overcoming the innate difficulties of working with amyloid‐β, including the peptide's low endogenous concentrations, the dynamic nature of its oligomeric states, and its heterogeneous and complex membrane interactions. SMM techniques have revealed that small oligomers of the peptide bind to model membranes and cells at low nanomolar‐to‐picomolar concentrations and diffuse at rates dependent on the membrane characteristics. These methods have also shown that oligomers grow or dissociate based on the presence of specific inhibitors or promoters and on the ratio of Aβ40 to Aβ42. Here, we discuss several types of single‐molecule imaging that have been applied to the study of Aβ oligomers and their membrane interactions. We also summarize some of the recent insights SMM has provided into oligomer behavior in solution, on planar lipid membranes, and on living cell membranes. A brief overview of the current limitations of the technique, including the lack of sensitive assays for Aβ‐induced toxicity, is included in hopes of inspiring future development in this area of research.
The mechanism of binding of the KIX domain to the mixed lineage leukemia protein and its allosteric role in the recognition of c‐Myb
Authors: Toto Angelo , Giri Rajanish , Brunori Maurizio , Gianni Stefano
Published: April 2014

The KIX domain is a mediator of the interaction between different transcription factors. This complex function is carried out via two distinct binding sites located on opposite sides of the protein; namely, the ‘c‐Myb site’ and the ‘MLL site’, named after their characteristic ligands—the transactivation domain of c‐Myb and the mixed lineage leukemia protein (MLL). Both these ligands are unstructured in isolation and fold only upon binding, posing the KIX domain as an ideal candidate to explore the binding induced folding reaction of intrinsically unstructured proteins. Here, we complement the recent kinetic description on the interaction between KIX and c‐Myb, by characterizing the binding kinetics between KIX and MLL, at different pH and ionic strength conditions. Furthermore, we analyze quantitatively the mechanism of allosteric communication between the topologically distinct c‐Myb and MLL sites. The implications of our results are discussed in the light of previous work on other intrinsically unstructured systems.
Measuring membrane protein bond orientations in nanodiscs via residual dipolar couplings
Authors: Bibow Stefan , Carneiro Marta G. , Sabo T. Michael , Schwiegk Claudia , Becker Stefan , Riek Roland , Lee Donghan
Published: April 2014

Membrane proteins are involved in numerous vital biological processes. To understand membrane protein functionality, accurate structural information is required. Usually, structure determination and dynamics of membrane proteins are studied in micelles using either solution state NMR or X‐ray crystallography. Even though invaluable information has been obtained by this approach, micelles are known to be far from ideal mimics of biological membranes often causing the loss or decrease of membrane protein activity. Recently, nanodiscs, which are composed of a lipid bilayer surrounded by apolipoproteins, have been introduced as a more physiological alternative than micelles for NMR investigations on membrane proteins. Here, we show that membrane protein bond orientations in nanodiscs can be obtained by measuring residual dipolar couplings (RDCs) with the outer membrane protein OmpX embedded in nanodiscs using Pf1 phage as an alignment medium. The presented collection of membrane protein RDCs in nanodiscs represents an important step toward more comprehensive structural and dynamical NMR‐based investigations of membrane proteins in a natural bilayer environment.
Aligned carbon nanotube‐liquid silicone rubber conductors and electrode surfaces for stimulating medical implants
Authors: Tegtmeier Katharina , Aliuos Pooyan , Stieghorst Jan , Schickedanz Malte , Golly Felix , Zernetsch Holger , Glasmacher Birgit , Doll Theodor
Published: April 2014

Cochlear implants restore the inner ear hearing using electrical stimulation of the auditory nerve. However, there is potential to improve the implant's function in terms of stimulation selectivity by increasing the number of electrode contacts. Meanwhile, the electrode stiffness shall not be elevated, because this would enhance insertion trauma and fibrous tissue encapsulation of the implant. Since the increase in the number of electrode contacts results in an increase of electrode stiffness, novel materials are needed for manufacturing electrode shafts. Carbon nanotubes (CNTs) as electrode contacts offer new perspectives concerning mechanical properties and electrode‐nerve interfacing. However, by using CNTs immersed in liquid silicone rubber (LSR) as electrode material, the electrical conductivity of the bulk needs to be improved. The aim of this study was to investigate the potential of using CNT–LSR as electrode material by increasing the conductivity of such materials and confirming their biocompatibility. First results show, that the electrode material can be printed in isolated layers, while the conductivity of the bulk can be improved. Fibroblasts growth tests indicated biocompatible properties of CNT–LSR samples. In conclusion CNT–LSR materials can be considered as promising candidates for use in neural implants possessing proper mechanical, electrical as well as biocompatible properties.
Spin switching: From quantum to quasiclassical approach
Authors: Chudnovskiy A. , Hübner Ch. , Baxevanis B. , Pfannkuche D.
Published: April 2014

In this paper, we review the theory of spin switching for systems of different sizes, from a quantum mechanical master equation approach for small atomic clusters to the quasiclassical description of spin dynamics by a stochastic Landau–Lifshits–Gilbert equation in metallic nanoscale magnetic systems. We present characteristic results emphasizing the role of the quantum character of spin at different scales. Comparing the quantum mechanical and the quasiclassical approach to spin switching, we draw analogies between the factors affecting quantum and classical spin dynamics. We analyze assumptions used in each approach and emphasize the limits of applicability of the quantum mechanical and of the quasiclassical descriptions.
Electron waveguide interferometers for spin‐dependent transport experiments
Authors: Chiatti Olivio , Buchholz Sven S. , Kunze Ulrich , Reuter Dirk , Wieck Andreas D. , Fischer Saskia F.
Published: April 2014

Semiconductor nanostructures are of interest in the field of spintronics, because they allow us to employ special features of low‐dimensional transport for spin polarization, manipulation, and detection. Proposals for spintronic devices are based on coherent transport and interference effects in extended electron waveguide (EWG) structures. We present the state‐of‐the‐art of low‐dimensional EWGs and Aharonov–Bohm (AB) interferometers, fabricated in GaAs/AlGaAs heterostructures. Low‐temperature measurements in etched quantum point contacts (QPCs) show large subband spacing and, in the presence of a source–drain DC bias, the differential conductance is resonantly enhanced due to a many‐body modification of the barrier potential because of spin fluctuations. Multiterminal asymmetric quantum wire rings (QRs) have been fabricated and AB conductance oscillations are used to detect electrostatically induced continuous phase shifts and‐phase jumps, due to resonances and reflections at cross‐junctions. The effects of measurement configuration and non‐equilibrium in QR structures are also studied. By embedding a QPC into the leads of a QR, coherent mode‐filtered injection of electrons into a few‐mode AB interferometer is demonstrated. Single‐ and few‐mode spin transport in EWG interferometers is discussed and the opportunities offered by embedding quantum dots for studying interaction and spin effects are presented. The results encourage the investigation of spin‐dependent quantum transport in extended EWG interferometers.
Magnetoelastic coupling and the formation of adaptive martensite in magnetic shape memory alloys
Authors: Gruner Markus Ernst , Fähler Sebastian , Entel Peter
Published: April 2014

Reviewing the results of recent first‐principles calculations, we work out a close analogy between the two paradigmatic classes of magnetic shape memory materials, the ordered Ni2MnGa Heusler compound and the disordered Fe70Pd30alloy. Despite fundamental differences between both systems, we can demonstrate that in both cases the very low formation energy for tetragonal twins on the smallest length scale opens an alternative transformation path into an adaptive hierarchical microstructure which is important for the functional behavior. The low energy of the (101) twin boundary corresponds to a shear instability which is associated to the soft transversal acoustic phonon in both systems. In turn, changes of the energy landscape upon magnetic disorder are responsible for the stability of austenite. This points out the strong influence of magnetoelastic coupling on the transformation process.

Nanotwinned adaptive microstructures in Ni2MnGa and Fe68Pd32magnetic shape memory alloys obtained from first‐principles calculations.
Hohenberg–Kohn theorems in the presence of magnetic field
Authors: Laestadius Andre , Benedicks Michael
Published: April 2014

In this article, we examine Hohenberg–Kohn theorems for Current Density Functional Theory, that is, generalizations of the classical Hohenberg–Kohn theorem that includes both electric and magnetic fields. In the Vignale and Rasolt formulation (Vignale and Rasolt, Phys. Rev. Lett. 1987, 59, 2360), which uses the paramagnetic current density, we address the issue of degenerate ground states and prove that the ensemble‐representable particle and paramagnetic current density determine the degenerate ground states. For the formulation that uses the total current density, we note that the proof suggested by Diener (Diener, J. Phys.: Condens. Matter. 1991, 3, 9417) is unfortunately not correct. Furthermore, we give a proof that the magnetic field and the ensemble‐representable particle density determine the scalar and vector potentials up to a gauge transformation. This generalizes the result of Grayce and Harris (Grayce and Harris, Phys. Rev. A 1994, 50, 3089) to the case of degenerate ground states. We moreover prove the existence of a positive wavefunction that is the ground state of infinitely many different Hamiltonians. © 2014 Wiley Periodicals, Inc.
On handling negative transfer and imbalanced distributions in multiple source transfer learning
Authors: Ge Liang , Gao Jing , Ngo Hung , Li Kang , Zhang Aidong
Published: April 2014

Transfer learning has benefited many real‐world applications where labeled data are abundant in source domains but scarce in the target domain. As there are usually multiple relevant domains where knowledge can be transferred, multiple source transfer learning (MSTL) has recently attracted much attention. However, we are facing two major challenges when applying MSTL. First, without knowledge about the difference between source and target domains, negative transfer occurs when knowledge is transferred from highly irrelevant sources. Second, existence of imbalanced distributions in classes, where examples in one class dominate, can lead to improper judgement on the source domains' relevance to the target task. Since existing MSTL methods are usually designed to transfer from relevant sources with balanced distributions, they will fail in applications where these two challenges persist. In this article, we propose a novel two‐phase framework to effectively transfer knowledge from multiple sources even when there exists irrelevant sources and imbalanced class distributions. First, an effective supervised local weight scheme is proposed to assign a proper weight to each source domain's classifier based on its ability of predicting accurately on each local region of the target domain. The second phase then learns a classifier for the target domain by solving an optimization problem which concerns both training error minimization and consistency with weighted predictions gained from source domains. A theoretical analysis shows that as the number of source domains increases, the probability that the proposed approach has an error greater than a bound is becoming exponentially small. We further extend the proposed approach to an online processing scenario to conduct transfer learning on continuously arriving data. Extensive experiments on disease prediction, spam filtering and intrusion detection datasets demonstrate that: (i) the proposed two‐phase approach outperforms existing MSTL approaches due to its ability of tackling negative transfer and imbalanced distribution challenges, and (ii) the proposed online approach achieves comparable performance to the offline scheme.
Causal inference of interaction effects with inverse propensity weighting, G‐computation and tree‐based standardization
Authors: Kang Joseph , Su Xiaogang , Liu Lei , Daviglus Martha L.
Published: April 2014

Given the recent interest of subgroup‐level studies and personalized medicine, health research with causal inference has been developed for interaction effects of measured confounders. In estimating interaction effects, the inverse of the propensity weighting (IPW) method has been widely advocated despite the immediate availability of other competing methods such as G‐computation estimates. This paper compares the advocatedIPWmethod, the G‐computation method, and our new Tree‐based standardization method, which we call the Interaction effect Tree (IT). TheITprocedure uses a likelihood‐based decision rule to divide the subgroups into homogeneous groups where the G‐computation can be applied. Our simulation studies indicate that theIT‐based method along with the G‐computation works robustly while the advocatedIPWmethod needs some caution in its weighting. We applied theIT‐based method to assess the effect of being overweight or obese on coronary artery calcification (CAC) in the Chicago Healthy Aging Study cohort.
How do Corporate Venture Capitalists do Deals? An Exploration of Corporate Investment Practices
Authors: Souitaris Vangelis , Zerbinati Stefania
Published: April 2014

How do corporate venture capitalists (CVCs) do deals? Conversations with CVCs suggest that the putative view of venture capital investing is incomplete. We draw on 13 cases of CVC programs to document eight ‘corporate investment practices’ that are unique to CVCs. These practices reflect pressure on the CVC units for strategic fit and engagement with the corporation and also an opportunity to utilize parental resources. We then show that CVCs vary their emphasis on corporate investment practices, diverging into two distinct investment logics, ‘integrated’ versus ‘arm's‐length.’ Focus of isomorphism on internal versus external stakeholders explains the emergence of the two logics. Copyright © 2014 Strategic Management Society.
Multifunctional Yolk‐in‐Shell Nanoparticles for pH‐triggered Drug Release and Imaging
Authors: Chen Hongyu , Qi Bin , Moore Thomas , Wang Fenglin , Colvin Daniel C. , Sanjeewa Liurukara D. , Gore John C. , Hwu Shiou‐Jyh , Mefford O. Thompson , Alexis Frank , Anker Jeffrey N.
Published: April 2014

Multifunctional nanoparticles are synthesized for both pH‐triggered drug release and imaging with radioluminescence, upconversion luminescent, and magnetic resonance imaging (MRI). The particles have a yolk‐in‐shell morphology, with a radioluminescent core, an upconverting shell, and a hollow region between the core and shell for loading drugs. They are synthesized by controlled encapsulation of a radioluminescent nanophosphor yolk in a silica shell, partial etching of the yolk in acid, and encapsulation of the silica with an upconverting luminescent shell. Metroxantrone, a chemotherapy drug, was loaded into the hollow space between X‐ray phosphor yolk and up‐conversion phosphor shell through pores in the shell. To encapsulate the drug and control the release rate, the nanoparticles are coated with pH‐responsive biocompatible polyelectrolyte layers of charged hyaluronic acid sodium salt and chitosan. The nanophosphors display bright luminescence under X‐ray, blue light (480 nm), and near infrared light (980 nm). They also served as T1 and T2 MRI contrast agents with relaxivities of 3.5 mM−1 s−1 (r1) and 64 mM−1s−1 (r2). These multifunctional nanocapsules have applications in controlled drug delivery and multimodal imaging.
Silicon Decorated Cone Shaped Carbon Nanotube Clusters for Lithium Ion Battery Anodes
Authors: Wang Wei , Ruiz Isaac , Ahmed Kazi , Bay Hamed Hosseini , George Aaron S. , Wang Johnny , Butler John , Ozkan Mihrimah , Ozkan Cengiz S.
Published: April 2014

In this work, we report the synthesis of an three‐dimensional (3D) cone‐shape CNT clusters (CCC) via chemical vapor deposition (CVD) with subsequent inductively coupled plasma (ICP) treatment. An innovative silicon decorated cone‐shape CNT clusters (SCCC) is prepared by simply depositing amorphous silicon onto CCC via magnetron sputtering. The seamless connection between silicon decorated CNT cones and graphene facilitates the charge transfer in the system and suggests a binder‐free technique of preparing lithium ion battery (LIB) anodes. Lithium ion batteries based on this novel 3D SCCC architecture demonstrates high reversible capacity of 1954 mAh g−1 and excellent cycling stability (>1200 mAh g−1 capacity with ≈100% coulombic efficiency after 230 cycles).
Analysis of Spalling in Roughing Mill Backup Rolls of Wide and Thin Strip Hot Rolling Process
Authors: Dong Qiang , Cao Jian‐guo , Li Hong‐bo , Zhou Yun‐song , Yan Tan‐li , Wang Wu‐zhou
Published: April 2014

In this paper, the spalling causes of backup rolls in a roughing mill of a hot strip rolling mill were investigated. The roughing mill withstood extreme service conditions with long service cycles for backup and work rolls, a large variety of the same width rolling campaigns, severe and non‐uniform wear contours of backup and work rolls. Analysis of cyclic stress applied on backup rolls indicated that contact stress played a dominant role in rolling contact fatigue which led to spalling on the backup roll surface. A 3D finite element model of roll system was established and contact stresses between rolls in whole service periods of backup and work rolls were calculated. The simulation results showed that roll wear had significant impact on contact stress distribution. In particular, the severe and non‐uniform U‐typed wear contours of work rolls led to produce huge contact stress peak in two sides of the rolls, where existed large cracks by eddy current inspection of post‐service backup rolls. Backup rolls stood thousands of times stress cycle in a service period, they were liable to fatigue damage in these areas. A new backup roll contour was developed to improve contact stress distribution and no spalling accidents were happened any longer after applied to the roughing mill.
Asymmetrical expression of BDNF and NTRK3 genes in frontoparietal cortex of stress‐resilient rats in an animal model of depression
Authors: Farhang Sara , Barar Jaleh , Fakhari Ali , Mesgariabbasi Mehran , Khani Sajjad , Omidi Yadollah , Farnam Alireza
Published: April 2014

The current study is based on the “approach–withdrawal” theory of emotional regulation and lateralization of brain function in rodents, which has little been studied. The aim was to indentify asymmetry in hemispheric genes expression during depression. Depressive‐like symptoms were induced in rats using chronic mild stress protocol. The sucrose consumption test was performed to identify the anhedonic and stress‐resilient rats. After decapitation, RNA was extracted from frontotemporal cortex of both hemispheres of anhedonic and stress‐resilient rats. The pattern of gene expression in these samples was compared with controls by real‐time polymerase chain reaction. A linear mixed model analysis of variance was fitted to the data to estimate the effect of rat line. From the total of 30 rats in the experimental group, five rats were identified to be anhedonic and five were stress‐resilient, according to the result of sucrose‐consumption test. BDNF and NTRK‐3 were expressed at significantly lower levels in the right hemisphere of anhedonic rats compared with stress‐resilient rats. No significant difference was found between left hemispheres. Hemispheric asymmetry in the level of gene expression was only observed for the BDNF gene in stress‐resilient rats, upregulated in right hemisphere compared with the left. Expression of NTRK3, HTR2A, COMT, and SERT was not lateralized. There was no significant asymmetry between hemispheres of anhedonic rats. This study supports the evidence for the role of genes responsible for neural plasticity in pathophysiology of depression, emphasizing probable hemispheric asymmetry at level of gene expression. Synapse, 2014. © 2014 Wiley Periodicals, Inc.
Empty Names and Pragmatic Millianism
Authors: Mousavian Seyed N. ,   Philosophy Documentation Center
Published: April 2014

Millianism is the view that the semantic content of a proper name is its semantic referent. Empty names, names with no semantic referents, raise various problems for Millianism. To solve these problems, many have appealed to pragmatics, thus ‘Pragmatic Millianism’. Pragmatic Millianism employs the relation of association between names and descriptions as well as some pragmatic processes to substitute empty names with descriptions associated with. The resultant content should account for the intuitions raised by utterances of sentences containing empty names. Here, I will try to argue against this picture: Names are associated with descriptions of different kinds in a number of ways. The complex nature of this relation is overlooked by Pragmatic Millianism. Neither the relation of association nor the pragmatic processes responsible for substituting a description or a cluster of descriptions for an empty name guarantee the fullness of what is pragmatically imparted. The moral is this: Regarding empty names, Pragmatic Millianism should be avoided.
Hypothyroxinemia induced by maternal mild iodine deficiency impairs hippocampal myelinated growth in lactational rats
Authors: Wei Wei , Wang Yi , Dong Jing , Wang Yuan , Min Hui , Song Binbin , Shan Zhongyan , Teng Weiping , Xi Qi , Chen Jie
Published: April 2014

Hypothyroxinemia induced by maternal mild iodine deficiency causes neurological deficits and impairments of brain function in offspring. Hypothyroxinemia is prevalent in developing and developed countries alike. However, the mechanism underlying these deficits remains less well known. Given that the myelin plays an important role in learning and memory function, we hypothesize that hippocampal myelinated growth may be impaired in rat offspring exposed to hypothyroxinemia induced by maternal mild iodine deficiency. To test this hypothesis, the female Wistar rats were used and four experimental groups were prepared: (1) control; (2) maternal mild iodine deficiency diet inducing hypothyroxinemia; (3) hypothyroidism induced by maternal severe iodine deficiency diet; (4) hypothyroidism induced by maternal methimazole water. The rats were fed the diet from 3 months before pregnancy to the end of lactation. Our results showed that the physiological changes occuring in the hippocampal myelin were altered in the mild iodine deficiency group as indicated by the results of immunofluorescence of myelin basic proteins on postnatal day 14 and postnatal day 21. Moreover, hypothyroxinemia reduced the expressions of oligodendrocyte lineage transcription factor 2 and myelin‐related proteins in the treatments on postnatal day 14 and postnatal day 21. Our data suggested that hypothyroxinemia induced by maternal mild iodine deficiency may impair myelinated growth of the offspring. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1264–1274, 2015.