bluuebunny/crossref_metadata_2025 huggingface dataset:
Alterations in local thyroid hormone signaling in the hippocampus of the SAMP8 mouse at younger ages: Association with delayed myelination and behavioral abnormalities
Authors: Sawano Erika , Negishi Takayuki , Aoki Tomoyuki , Murakami Masami , Tashiro Tomoko
Published: December 2012

The senescence‐accelerated mouse (SAM) strains were established through selective inbreeding of the AKR/J strain based on phenotypic variations of aging and consist of senescence‐prone (SAMP) and senescence‐resistant (SAMR) strains. Among them, SAMP8 is considered as a model of neurodegeneration displaying age‐associated learning and memory impairment and altered emotional status. Because adult hypothyroidism is one of the common causes of cognitive impairment and various psychiatric disorders, we examined the possible involvement of thyroid hormone (TH) signaling in the pathological aging of SAMP8 using the senescence‐resistant SAMR1 as control. Although plasma TH levels were similar in both strains, a significant decrease in type 2 deiodinase (D2) gene expression was observed in the SAMP8 hippocampus from 1 to 8 months of age, which led to a 35–50% reductions at the protein level and 20% reduction of its enzyme activity at 1, 3, and 5 months. D2 is responsible for local conversion of thyroxine into transcriptionally active 3,5,3′‐triiodothyronine (T3), so the results suggest a reduction in T3 level in the SAMP8 hippocampus. Attenuation of local TH signaling was confirmed by downregulation of TH‐dependent genes and by immunohistochemical demonstration of delayed and reduced accumulation of myelin basic protein, the expression of which is highly dependent on TH. Furthermore, we found that hyperactivity and reduced anxiety were not age‐associated but were characteristic of young SAMP8 before they start showing impairments in learning and memory. Early alterations in local TH signaling may thus underlie behavioral abnormalities as well as the pathological aging of SAMP8. © 2012 Wiley Periodicals, Inc.
Sleep Quality Among U.S. Military Veterans With PTSD: A Factor Analysis and Structural Model of Symptoms
Authors: Babson Kimberly A. , Blonigen Daniel M. , Boden Matthew Tyler , Drescher Kent D. , Bonn‐Miller Marcel O.
Published: December 2012

Poor sleep quality among individuals with posttraumatic stress disorder (PTSD) is associated with poorer prognosis and outcomes. The factor structure of the most commonly employed measure of self‐reported sleep quality, the Pittsburgh Sleep Quality Index (PSQI), has yet to be evaluated among individuals with PTSD. The current study sought to fill this gap among a sample of 226 U.S. military veterans with PTSD (90% with co‐occurring mood disorders, 73.5% with substance use disorders). We evaluated the factor structure of the PSQI by conducting an exploratory factor analysis (EFA) in approximately half of the sample (n = 111). We then conducted a second EFA in the other split half (n = 115). Lastly, we conducted a path analysis to investigate the relations between sleep factors and PTSD symptom severity, after accounting for the relation with depression. Results suggested sleep quality can best be conceptualized, among those with PTSD, as a multidimensional construct consisting of 2 factors, Perceived Sleep Quality and Efficiency/Duration. After accounting for the association between both factors and depression, only the Perceived Sleep Quality factor was associated with PTSD (β = .51). The results provide a recommended structure that improves precision in measuring sleep quality among veterans with PTSD.
Attachment, Personality Characteristics, and Posttraumatic Stress Disorder in U.S. Veterans of Iraq and Afghanistan
Authors: Clark Allison A. , Owens Gina P.
Published: December 2012

U.S. veterans of Iraq and/or Afghanistan (N = 116) completed an Internet survey with questions related to attachment style in intimate relationships, personality factors, and posttraumatic stress disorder (PTSD). Participants completed the PTSD Checklist‐Military, Experiences in Close Relationships Scale‐Short Form, and the International Personality Item Pool Big Five Short Form Questionnaire. Most participants were male and Caucasian. Hierarchical linear regression analysis results indicated that emotional stability (β = −.46, p < .001) and attachment avoidance (β = .20, p < .05) were associated with PTSD symptom severity (adjusted R2 = .63). An interaction between conscientiousness and attachment anxiety was found (β = −.26, p < .001; ΔR2 = .06), with secure attachment moderating the relationship between conscientiousness and PTSD symptom severity. Results of this study indicate that emotional stability, conscientiousness, and secure relationship attachment styles (low attachment anxiety and avoidance) are important for postcombat mental health.
Heterozygote deficiencies caused by a Wahlund effect: Dispelling unfounded expectations
Authors: Dharmarajan Guha , Beatty William S. , Rhodes Olin E.
Published: December 2012

Population genetic tools can facilitate successful conservation and management of wildlife populations. However, the ability of such approaches to inform wildlife management and conservation programs depends upon assumptions linking genetic patterns to ecological processes, one implicit assumption usually being that genetic parameters (e.g., population genetic differentiation) estimated using a set of loci accurately reflect underlying demographic and microevolutionary forces affecting the population(s) under study. This is an important assumption because it also implies that we have acknowledged that genetic parameters estimated by a set of target loci inherently are associated with a sampling variance. Specifically, a perception exists that heterozygote deficits caused by biological mechanisms (e.g., a Wahlund effect) and null alleles can be differentiated by the expectation that the former leads to a concordant pattern across all loci, whereas the latter leads to locus‐specific effects. We use Monte‐Carlo simulation to demonstrate that these expectations do not always hold under biologically realistic conditions. Our analyses indicate that the conservative approach of discarding loci deviating from Hardy‐Weinberg equilibrium expectations could rob us of our most informative markers, weakening our ability to interpret biological phenomena. © 2012 The Wildlife Society.
Design Strategies and Applications of Tissue Bioadhesives
Authors: Mehdizadeh Mohammadreza , Yang Jian
Published: December 2012

In the past two decades tissue adhesives and sealants have revolutionized bleeding control and wound healing. This paper focuses on existing tissue adhesive design, their structure, functioning mechanism, and their pros and cons in wound management. It also includes the latest advances in the development of new tissue adhesives as well as the emerging applications in regenerative medicine. We expect that this paper will provide insightful discussion on tissue bioadhesive design and lead to innovations for the development of the next generation of tissue bioadhesives and their related biomedical applications.

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Music to Your Brain: Background Music Changes Are Processed First, Reducing Ad Message Recall
Authors: Fraser Cynthia , Bradford J. Andrew
Published: December 2012

Background music captures attention, evokes images, and creates ambience, but may interfere with processing of advertised messages, reducing recall. Brains are hardwired to process unexpected background sound changes first, automatically preempting processing of brand message elements and reducing recall. The degree of this recall reduction depends on the structural characteristics of the music, as well as the advertised brand. Backgrounds with more frequent harmonic and textural changes create more frequent distraction, reducing message recall. Faster tempos increase the frequency of those distractions. However, faster tempos also enable streaming of like distractions, improving message recall. In Experiment 1, backgrounds, varying in harmonic, textural, and temporal characteristics, were compared across ads for six brands. Message recall was higher for ads with backgrounds with less‐frequent change. Message recall from ads for new, unfamiliar brands suffered more from background music interference than from ads for established brands. In Experiment 2, background change frequency was reduced in two ads, holding all else constant, which improved message recall.
Carbon Nanotube‐Directed Polytetrafluoroethylene Crystal Growth via Initiated Chemical Vapor Deposition
Authors: Laird Eric D. , Bose Ranjita K. , Wang Wenda , Lau Kenneth K. S. , Li Christopher Y.
Published: December 2012

Initiated chemical vapor deposition (iCVD) has been shown to be suitable for blanketing surfaces with thin polymer coatings of ≈1–2 nm and greater. In this work, iCVD coatings of polytetrafluoroethylene (PTFE) deposited on carbon nanotube (CNT)‐based surfaces show CNT‐templated PTFE single crystal growth. While the coating forms disoriented agglomerates when deposited on an amorphous carbon background, “shish‐kebab” structures are observed when grown on single‐walled carbon nanotubes (SWCNT) as well as CNT buckypaper. It is shown that the shish‐kebab structure is composed of PTFE lamellae arranged with the chain backbones running parallel to the SWCNT axis. This result allows one to control not only the surface chemistry using PTFE but also the coating surface topology.
β‐amyloid in lewy body disease is related to Alzheimer's disease‐like atrophy
Authors: Shimada Hitoshi , Shinotoh Hitoshi , Hirano Shigeki , Miyoshi Michie , Sato Koichi , Tanaka Noriko , Ota Tsuneyoshi , Fukushi Kiyoshi , Irie Toshiaki , Ito Hiroshi , Higuchi Makoto , Kuwabara Satoshi , Suhara Tetsuya
Published: December 2012

The aim of this study was to investigate whether amyloid deposition is associated with Alzheimer's disease (AD)‐like cortical atrophy in Lewy body (LB) disease (LBD). Participants included 15 LBD with dementia patients (8 with dementia with Lewy bodies [DLB] and 7 with Parkinson's disease [PD] with dementia [PDD]), 13 AD patients, and 17 healthy controls. Age, gender, and Mini–Mental State Examination scores were matched between patient groups. All subjects underwent PET scans with [11C]Pittsburgh Compound B to measure brain amyloid deposition as well as three‐dimensional T1‐weighted MRI. Gray‐matter volumes (GMVs) were estimated by voxel‐based morphometry. Volumes‐of‐interest analyses were also performed. Forty percent of the 15 DLB/PDD patients were amyloid positive, whereas all AD patients and none of the healthy controls were amyloid positive. Amyloid‐positive DLB/PDD and AD patients showed very similar patterns of cortical atrophy in the parahippocampal area and lateral temporal and parietal cortices, with 95.2% of cortical atrophy distribution being overlapped. In contrast, amyloid‐negative DLB/PDD patients had no significant cortical atrophy. Compared to healthy controls, parahippocampal GMVs were reduced by 26% in both the amyloid‐positive DLB/PDD and AD groups and by 10% in the amyloid‐negative DLB/PDD group. The results suggest that amyloid deposition is associated with AD‐like atrophy in DLB/PDD patients. Early intervention against amyloid may prevent or delay AD‐like atrophy in DLB/PDD patients with amyloid deposition. © 2012 Movement Disorder Society
Analysis of the fractional Kawahara equation using an implicit fully discrete local discontinuous Galerkin method
Authors: Wei Leilei , He Yinnian , Tang Bo
Published: December 2012

In this article, an implicit fully discrete local discontinuous Galerkin (LDG) finite element method, on the basis of finite difference method in time and LDG method in space, is applied to solve the time‐fractional Kawahara equation, which is introduced by replacing the integer‐order time derivatives with fractional derivatives. We prove that our scheme is unconditional stable and convergent through analysis. Extensive numerical results are provided to demonstrate the performance of the present method. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
Entheseal Changes and Functional Implications of the Humeral Medial Epicondyle
Authors: Ibáñez‐Gimeno P. , Galtés I. , Jordana X. , Fiorin E. , Manyosa J. , Malgosa A.
Published: December 2012

Longitudinal rotation of the forearm (pronosupination) is an essential component of human manipulative tasks. The efficiency of this movement is dependent not only on the rotatory muscles but also on several morphological and structural features of the upper limb. In a recent study, we observed that the size and orientation of the humeral medial epicondyle played an important role in forearm rotatory ability. We further observed that the forearm muscular activity, specifically the motion of pronation, promotes radial curvature, which, in turn, enhances rotational efficiency. In this study, we aim to test whether the orientation of the medial epicondyle is an activity‐dependent parameter or whether it is an invariable morphological feature characteristic of the human skeleton. We analysed the upper limb entheseal changes in 30 human skeletons and assessed the role of several functional groups in the anteroposterior and proximo‐distal orientation of the medial epicondyle. Our results indicate that the orientation of the medial epicondyle is partially an activity‐dependent feature basically determined by elbow flexor‐extensors and hand and wrist flexors. The orientation of the medial epicondyle towards more posterior and proximal positions causes a gain of efficiency in the pronation range when the elbow is extended and in the supination range when the elbow is flexed. Therefore, we suggest that the medial epicondyle of the humerus is a structure involved in the manipulative capacities of the human upper limb, and its orientation presents a range of variation that may be associated with the functional enhancement of these abilities. Copyright © 2012 John Wiley & Sons, Ltd.
Effects of modified attapulgite on the properties of attapulgite/epoxy nanocomposites
Authors: Wang Rongguo , Li Zheng , Wang Yumei , Liu Wenbo , Deng Libo , Jiao Weicheng , Yang Fan
Published: December 2012

The aim of this work is to figure out the true effects of filler modification in attapulgite (ATP)/epoxy (EP) nanocomposites through comparing the properties of composites containing pristine or modified ATP clay. ATP particles were first pretreated by a silane coupling agent KH550 and cationic surfactant cetyl trimethyl ammonium bromide (CTAB) separately, and then a series of nanocomposites were prepared with varied clay loadings. Fourier transform infrared spectroscopy and thermogravimetric analysis were used to confirm the modification. The wicking experiment showed the compatibility of ATP with EP increased after modification, especially for CTAB‐ATP, which was discovered to exhibit the highest affinitive ratio. Mechanical and thermal properties of the composites were enhanced on the introduction of ATP. Regarding the efficiency of mechanical reinforcement, KH550 was superior to CTAB at lower ATP loadings (<2 wt%), whereas CTAB became relatively more effective at higher loadings. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers
Studies on synthesis and characterization of poly(methyl methacrylate)‐bentonite clay composite by emulsion polymerization and simultaneous in situ clay incorporation
Authors: Modak Sadhan Kumar , Mandal Arup , Chakrabarty Debabrata
Published: December 2012

Well‐dispersed poly(methyl methacrylate) (PMMA)–bentonite clay composite was synthesized by emulsion polymerization using methyl methacrylate (MMA) monomer and 3% sodium carbonate treated bentonite clay. The composite lost its transparency normally encountered with the neat PMMA. The composite was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), vicat softening point (VSP), dynamic mechanical thermal analysis (DMTA), and tensile studies. The morphology was investigated by scanning electron microscopy (SEM) and atomic forced microscopy (AFM) as well. The crystallography was studied to estimate the changes in crystallographic planes by X‐ray diffraction (XRD) analysis. The particle size distribution was compared amongst neat bentonite clay, neat PMMA and the composite. The FTIR spectra reveal the fact that no new primary valence bond is formed between the clay and PMMA. The thermal stability of the composite is significantly improved, as indicated by the TGA and VSP studies. A substantial increase in glass transition temperature (Tg) approximately, 10°C was recorded from the DMTA as both the storage modulus and tan δ values underwent inflexion at higher temperatures in case of the composite compared with the pristine PMMA. The XRD pattern indicates increase in basal “d” spacing for the composite. The morphology from both the SEM and AFM is quite supportive to well‐dispersed exfoliation. The incorporation of nanosized activated clay particles in PMMA during its in situ polymerization from MMA led to the formation of nanocomposites. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers
Optical percolation and oxygen diffusion in poly(divinylbenzene) doped poly(methyl methacrylate) latex flms
Authors: Yargı Ö.
Published: December 2012

A simple fluorescence technique is proposed for the measurement of the diffusion coefficient of oxygen into poly(methyl methacrylate) (PMMA) latex‐poly(divinylbenzene) (PDVB) composite films. Percolation model was used by using photon transmission (PT) technique to interpret the distribution of PDVB particles in PMMA lattice. Optical results were interpreted according to site percolation theory. The optical percolation threshold value and critical exponent were calculated as, Rc = 0.03 and, β = 0.34, respectively. PT measurements were performed for eight different PDVB content (0, 1.5, 3, 5, 10, 20, 40, and 60) wt%. Pyrene (P) functionalized PDVB cross‐linked spherical microspheres with diameters of 2.5 μm were synthesized by using precipitation polymerization technique followed by click coupling reaction. The diameter of the PMMA particles prepared by emulsion polymerization was in the range of 0.5–0.7 μm. PMMA/PDVB composite films were then prepared by physically blending of PMMA latex with PDVB microspheres at various compositions. The steady‐state fluorescence method was used to monitor oxygen diffusion into these (0, 5, 10, 20, and 40 wt%) latex films. Diffusion coefficients, D, of oxygen were determined by the fluorescence quenching method by assuming Fickian transport and were found to be increased from 1.8 × 10−11 to 36.6 × 10−11 cm2 s−1 with increasing PDVB content. This increase in D values was explained with formation of microvoids in the film by using PT technique. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers
Ammonium‐assisted green fabrication of graphene/natural rubber latex composite
Authors: Li Chengpeng , Feng Chunfang , Peng Zheng , Gong Wei , Kong Lingxue
Published: December 2012

Direct incorporation of nano reinforcement fillers has been a challenge for composite design because of strong aggregation. In this article, a stabilizer‐free method is developed to prepare new graphene/natural rubber latex (NRL) composite as the stabilizer ammonium was diffused completely in the final heat vulcanization. The as‐prepared composite was investigated by scanning electron microscopy, static mechanical analysis, dynamic thermal mechanical analysis, swelling analysis, and positron annihilation analysis. The results demonstrated that because of good dispersion and special two‐dimensional structure of the graphene, there is strong interfacial interaction originated from the π–π interactions and hydrogen bonds between graphene and NRL matrix even at a low loading. After the introduction of graphene, the glass transition temperature (Tg) and the crosslink density are improved to 6°C and 7%, respectively, with a slight decrease in overall free‐volume number (3.5%) and fraction (1%). It is also surprising to notice that the tensile strength of NRL is improved to 8% without compromising the elongation at break, which actually increases 3%. Therefore, ammonium‐assisted dispersion of graphene is feasible for graphene/NRL fabrication. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers
Fetal neural tube defects in pregnant women previously submitted to bariatric surgery: more attention to a new emerging entity
Authors: Pelizzo Gloria , Nakib Ghassan , Alfei Alessandro , Iasci Angela , Cena Hellas , Locatelli Davide , Mosconi Mario , Zappoli Federico , Calcaterra Valeria
Published: December 2012

What's already known about this topic?

The pathogenesis of neural tube defects is multifactorial.

What does this study add?

Although the pathogenesis of neural tube defects is certainly multifactorial, malnutrition after bariatric surgery has to be considered a major risk factor. Women who have undergone bariatric procedure must receive nutritional counselling before and after conception.
Playing Hard–To–Get: Manipulating One'S Perceived Availability as A Mate
Authors: Jonason Peter K. , Li Norman P.
Published: December 2012

‘Playing hard–to–get’ is a mating tactic in which people give the impression that they are ostensibly uninterested to get others to desire them more. This topic has received little attention because of theoretical and methodological limitations of prior work. We present four studies drawn from four different American universities that examined playing hard–to–get as part of a supply–side economics model of dating. In Studies 1a (N = 100) and 1b (N = 491), we identified the tactics that characterize playing hard–to–get and how often men and women enact them. In Study 2 (N = 290), we assessed reasons why men and women play hard–to–get along with the personality traits associated with these reasons. In Studies 3 (N = 270) and 4 (N = 425), we manipulated the rate per week prospective mates went out with people they had just met and assessed participants’ willingness to engage in casual sex and serious romantic relationships with prospective mates (Study 3) and the money and time they were willing to invest in prospective mates (Study 4). We frame our results using a sexual economics model to understand the role of perceived availability in mating dynamics. Copyright © 2012 European Association of Personality Psychology
Habitual Self–Control: A Brief Measure of Persistent Goal Pursuit
Authors: Schroder Kerstin Elisabeth Elfriede , Ollis Cindy L. , Davies Sydney
Published: December 2012

Habitual self–control is defined as a trait–like personal resource factor that facilitates the enactment of difficult intentions. A 14–item Habitual Self–Control Questionnaire (HSCQ) was developed to assess this trait. Reliability, factorial validity, and criterion validity were assessed in five undergraduate student subsamples with an overall N of 2224. Internal consistency was .81 across the entire sample, and test–retest reliability was .83 over a one–month interval. The HSCQ showed a theoretically meaningful pattern in terms of convergent and discriminant validity and criterion validity in predicting a variety of health behaviours that relate to self–control, including exercise, dieting behaviour, binge eating and weight loss success. Further, the HSCQ contributed uniquely to the prediction of health behaviours beyond alternative self–control scales. In a longitudinal part of the study, the HSCQ added to the prediction of action plan completion and satisfaction beyond motivation and moderated the relationship between motivation and enactment of action plans as theoretically expected. In sum, the results provided strong evidence for the reliability and validity of the HSCQ and highlighted some theoretically meaningful differences to already existing measures of self–control. Theoretical implications are discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Crystallization behavior and crystallite morphology control of poly(L‐lactic acid) through N, N′‐bis(benzoyl)sebacic acid dihydrazide
Authors: Fan Yinqing , Yu Zhuyi , Cai Yanhua , Hu Dingding , Yan Shifeng , Chen Xuesi , Yin Jingbo
Published: December 2012

Adding a nucleating agent is one of the best ways to accelerate the crystallization rate of poly(L‐lactic acid) (PLLA) so as to obtain a high degree of crystallinity during the process, which will improve the heat distortion temperature of final products. In the work reported, N, N′‐bis(benzoyl)sebacic acid dihydrazide (BSAD) was synthesized and used as a nucleating agent for PLLA. Isothermal and non‐isothermal crystallization behaviors were investigated using differential scanning calorimetry (DSC). The addition of BSAD successfully enhances the crystallization rate of PLLA. A unique phase separation behavior of PLLA/BSAD blends is found from DSC as well as from polarized optical microscopy, which explains the difference of optimal BSAD concentration between isothermal and non‐isothermal crystallization. This is the first recording of a phase separation peak in PLLA/nucleating agent blends using DSC. In thermogravimetric analysis, the enhanced thermal stability indicates that there are strong hydrogen bonds between BSAD and PLLA matrix. BSAD can dissolve in PLLA melt below its melting point through intermolecular hydrogen bonding with PLLA and self‐assemble upon cooling, leading to the surface being capable of nucleating PLLA. Different phase separation temperatures can be used to control the morphology of BSAD, which finally determines the crystallite morphology of PLLA. © 2012 Society of Chemical Industry
Insoluble porous conjugated polymer films via phase separation and photo‐crosslinking for the trace detection of 2,4‐dinitrotoluene
Authors: Leng Hongfei , Niu Qingyuan , Wu Wenhui
Published: December 2012

A novel conjugated polymer film with microscale/submicroscale porous morphology fabricated from crosslinked poly(fluorene‐co‐carbazole) (PFC1) was developed for the detection of 2,4‐dinitrotoluene (DNT). The fluorescent conjugated polymer PFC1 with pendant photo‐crosslinkable coumarin groups was synthesized by Suzuki coupling polymerization. Taking advantage of the phase separation of PFC1/polystyrene (PS) blends in the film and the solvent‐resistant network, porous structured films were prepared by removal of PS. Films with porous morphologies exhibited marked responsive sensitivity to trace DNT vapor due to the unique porous structure favoring the diffusion of and association with DNT molecules. The formation of a crosslinked network by dimerization of the coumarin moieties may be beneficial for isolating the polymeric backbones, thus to some extent preventing chain aggregation. This facile fabrication method enabled the crosslinked porous films to be efficient fluorescence chemosensors towards the detection of trace amounts of DNT vapor.© 2012 Society of Chemical Industry
The Internal Migration of Immigrants: Differences between One‐Time and Multiple Movers in Spain
Authors: Silvestre Javier , Reher David S.
Published: December 2012

Research on the mobility and residential patterns of immigrants within receiving countries is abundant. The selective nature of movers and the location of immigrants are issues that have received special attention. Most studies are premised on the supposition that immigrants move only once. However, for a number of immigrants, internal migration is a dynamic process in which more than one movement is involved. This article extends the literature by disaggregating immigrants according to their number of internal migrations. We use data from a new and rich retrospective survey to examine the determinants of migration trajectories and the effects of the location choices of immigrants. We elaborate a set of indicators to assess the importance of the spatial assimilation theory and other main theoretical frameworks. This article concentrates on Spain, a recent main migratory destination in Europe and worldwide. Results reveal the existence of significant differences between one‐time and multiple movers. The selective nature of multiple movers is explained in part by the spatial assimilation paradigm. Further results show that both one‐time and multiple movers tend to reside outside ethnic concentrations as a result of their mobility experience within Spain. Copyright © 2012 John Wiley & Sons, Ltd.
Structural and electronic properties of highly doped topological insulator Bi2Se3 crystals
Authors: Cao Helin , Xu Suyang , Miotkowski Ireneusz , Tian Jifa , Pandey Deepak , Hasan M. Zahid , Chen Yong P.
Published: December 2012

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We present a study of the structural and electronic properties of highly doped topological insulator Bi2Se3 single crystals synthesized by the Bridgman method. Lattice structural characterizations by X‐ray diffraction, scanning tunneling microscopy, and Raman spectroscopy confirmed the high quality of the as‐grown single crystals. The topological surface states in the electronic band structure were directly re‐ vealed by angle‐resolved photoemission spectroscopy. Transport measurements showed that the conduction was dominated by the bulk carriers and confirmed a previously observed bulk quantum Hall effect in such highly doped Bi2Se3 samples. We briefly discuss several possible strategies of reducing bulk conductance. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tests of different flavours of EnKF on a simple model
Authors: Bowler Neill E. , Flowerdew Jonathan , Pring Stephen R.
Published: December 2012

The Met Office is currently developing an ensemble‐based data‐assimilation system for use in numerical weather prediction (NWP). In an effort to inform those developments, a simple model has been used to compare a number of different flavours of ensemble Kalman filter (EnKF). As in many previous studies, deterministic (square‐root) filters are seen to perform better than stochastic (perturbed‐observations) filters. Two previously proposed methods for mitigating the effects of perturbing the observations were tested. These modified stochastic filters improved performance, but were still worse than the deterministic filters. Very little difference was seen between the performance of the various deterministic filters tested.

The typical approach to localization in the Local Ensemble Transform Kalman Filter (LETKF) is based solely on the distance between each observation and the model point being updated. It takes no account of the inter‐observation distance and we argue that this is incorrect. However, the difference between covariance localization and observation localization is only relevant when the assimilation is not weak and hence it did not affect performance in these tests. If a hybrid covariance matrix is used to update the ‘deterministic’ forecast around which the ensemble is centred, then using the same covariance matrix when updating the perturbations is seen to be beneficial in a stochastic filter. This is not the case in the square‐root filter, due to restrictions imposed by its formulation. Tests with a nonlinear observation operator indicate better behaviour when observations are assimilated simultaneously rather than sequentially. An ensemble of variational minimizations has some advantages in this situation. These results, along with other considerations, have led the Met Office to develop a 4‐dimensional ensemble‐variational (4D‐En‐Var) system for data assimilation and ensemble generation.
Generalized loop‐erased random walks and approximate reachability
Authors: Gorodezky Igor , Pak Igor
Published: December 2012

In this paper we extend the loop‐erased random walk (LERW) to the directed hypergraph setting. We then generalize Wilson's algorithm for uniform sampling of spanning trees to directed hypergraphs. In several special cases, this algorithm perfectly samples spanning hypertrees in expected polynomial time. Our main application is to the reachability problem, also known as the directed all‐terminal network reliability problem. This classical problem is known to be # P‐complete, hence is most likely intractable (Ball and Provan, SIAM J Comput 12 (1983) 777–788). We show that in the case of bi‐directed graphs, a conjectured polynomial bound for the expected running time of the generalized Wilson algorithm implies a FPRAS for approximating reachability. Copyright © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 44, 201‐223, 2014
Measurement errors and scaling relations in astrophysics: a review
Authors: Andreon Stefano , Hurn Merilee
Published: December 2012

This review article considers some of the most common methods used in astronomy for regressing one quantity against another in order to estimate the model parameters or to predict an observationally expensive quantity using trends between object values. These methods have to tackle some of the awkward features prevalent in astronomical data, namely heteroscedastic (point‐dependent) errors, intrinsic scatter, non‐ignorable data collection and selection effects, data structure and non‐uniform population (often called Malmquist bias), non‐Gaussian data, outliers, and mixtures of regressions. We outline how least square fits, weighted least squares methods, Maximum Likelihood, survival analysis, and Bayesian methods have been applied in the astrophysics literature when one or more of these features is present. In particular we concentrate on errors‐in‐variables regression and we advocate Bayesian techniques. © 2013 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 6: 15–33, 2013
The trend odds model for ordinal data
Authors: Capuano Ana W. , Dawson Jeffrey D.
Published: December 2012

Ordinal data appear in a wide variety of scientific fields. These data are often analyzed using ordinal logistic regression models that assume proportional odds. When this assumption is not met, it may be possible to capture the lack of proportionality using a constrained structural relationship between the odds and the cut‐points of the ordinal values. We consider a trend odds version of this constrained model, wherein the odds parameter increases or decreases in a monotonic manner across the cut‐points. We demonstrate algebraically and graphically how this model is related to latent logistic, normal, and exponential distributions. In particular, we find that scale changes in these potential latent distributions are consistent with the trend odds assumption, with the logistic and exponential distributions having odds that increase in a linear or nearly linear fashion. We show how to fit this model using SAS Proc NLMIXED and perform simulations under proportional odds and trend odds processes. We find that the added complexity of the trend odds model gives improved power over the proportional odds model when there are moderate to severe departures from proportionality. A hypothetical data set is used to illustrate the interpretation of the trend odds model, and we apply this model to a swine influenza example wherein the proportional odds assumption appears to be violated. Copyright © 2012 John Wiley & Sons, Ltd.
Non‐ionic Dendronized Multiamphiphilic Polymers as Nanocarriers for Biomedical Applications
Authors: Gupta Shilpi , Schade Boris , Kumar Sumit , Böttcher Christoph , Sharma Sunil K. , Haag Rainer
Published: December 2012

A new class of non‐ionic dendronized multiamphiphilic polymers is prepared from a biodegradable (AB)n‐type diblock polymer synthesized from 2‐azido‐1,3‐propanediol (azido glycerol) and polyethylene glycol (PEG)‐600 diethylester using Novozym‐435 (Candida antarctica lipase) as a biocatalyst, following a well‐established biocatalytic route. These polymers are functionalized with dendritic polyglycerols (G1 and G2) and octadecyl chains in different functionalization levels via click chemistry to generate dendronized multiamphiphilic polymers. Surface tension measurements and dynamic light scattering studies reveal that all of the multiamphiphilic polymers spontaneously self‐assemble in aqueous solution. Cryogenic transmission electron microscopy further proves the formation of multiamphiphiles towards monodisperse spherical micelles of about 7–9 nm in diameter. The evidence from UV–vis and fluorescence spectroscopy suggests the effective solubilization of hydrophobic guests like pyrene and 1‐anilinonaphthalene‐8‐sulfonic acid within the hydrophobic core of the micelles. These results demonstrate the potential of these dendronized multiamphiphilic polymers for the development of prospective drug delivery systems for the solubilization of poorly water soluble drugs.
A Peptide Nanofibrous Indicator for Eye‐Detectable Cancer Cell Identification
Authors: Chen Chang‐Sheng , Xu Xiao‐Ding , Wang Ya , Yang Juan , Jia Hui‐Zhen , Cheng Han , Chu Chih‐Chang , Zhuo Ren‐Xi , Zhang Xian‐Zheng
Published: December 2012

A unique peptide nanofibrous indicator (NFI) is fabricated by mixing a borono‐peptide with alizarin red S, followed by subsequent binding and self‐assembly. The NFI thus obtained exhibits an intense response to sialyl Lewis X tetrasaccharide, which is overexpressed in human hepatocellular carcinoma cell lines. Importantly, this NFI has the capability of specifically recognizing human hepatocellular liver carcinoma (HepG2) cells through the eye‐detectable color change resulting from strong binding‐induced displacement. This novel technique for cancer cell identification through direct unaided eye judgment will open up an innovative platform for cancer cell detection.
Estimating optimal treatment regimes from a classification perspective
Authors: Zhang Baqun , Tsiatis Anastasios A. , Davidian Marie , Zhang Min , Laber Eric
Published: December 2012

A treatment regime maps observed patient characteristics to a recommended treatment. Recent technological advances have increased the quality, accessibility, and volume of patient‐level data; consequently, there is a growing need for powerful and flexible estimators of an optimal treatment regime that can be used with either observational or randomized clinical trial data. We propose a novel and general framework that transforms the problem of estimating an optimal treatment regime into a classification problem wherein the optimal classifier corresponds to the optimal treatment regime. We show that commonly employed parametric and semi‐parametric regression estimators, as well as recently proposed robust estimators of an optimal treatment regime can be represented as special cases within our framework. Furthermore, our approach allows any classification procedure that can accommodate case weights to be used without modification to estimate an optimal treatment regime. This introduces a wealth of new and powerful learning algorithms for use in estimating treatment regimes. We illustrate our approach using data from a breast cancer clinical trial. Copyright © 2012 John Wiley & Sons, Ltd.
“life's first need is for us to be realistic” and other reasons for examining the sociocultural construction of race in the science performance of African American students
Authors: Mutegi Jomo W.
Published: December 2012

The body of research aimed at explaining the science teaching and learning of African Americans has identified myriad factors that correlate with African American's science career choices and science performance generally. It has not, however, offered any satisfactory explanations as to why those factors are disproportionately racially determined. This article argues that the sociocultural construction of race, which has roots in antebellum Western society, has endured to the present day; and that there is sufficient historical tradition and empirical evidence to warrant a research agenda that accounts for the sociocultural construction of race in explaining African American science education. The article concludes by suggesting a set of research questions and theoretical perspectives that considers the sociocultural construction of race to guide future research. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 50:82–103, 2013
Risk‐invoked self‐scheduling of a Genco in a day‐ahead energy and spinning reserve market
Authors: Somasundaram Periasamy , Ramesh Babu Muthu
Published: December 2012

This paper proposes a solution methodology for risk‐invoked self‐scheduling of a price taker power producer in day‐ahead correlated energy and spinning reserve markets to accomplish a trade‐off between expected profit and risk levels based on Markowitz portfolio selection. In the self‐scheduling problem, a certain risk is invoked because of the uncertainty in the forecast electricity prices. To tackle the forecasting errors, variances of energy and spinning reserve along with their covariance are taken into account using the available data. This risk‐invoked self‐scheduling framework is therefore formulated as a mixed‐integer nonlinear problem. This paper proposes a solution methodology based on a novel Cauchy mutated memetic particle swarm optimization (CMMPSO) algorithm. The effectiveness of the proposed CMMPSO algorithm is demonstrated with two test cases, and the numerical results are discussed. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Epidemiology of dentin hypersensitivity
Authors: Splieth Christian H. , Tachou Aikaterini
Published: December 2012

Objective

In contrast to the well-established caries epidemiology, data on dentin hypersensitivity seem to be scarce and contradictory. This review evaluates the available literature on dentin hypersensitivity and assesses its prevalence, distribution, and potential changes.

Materials and methods

The systematic search was performed to identify and select relevant publications with several key words in electronic databases. In addition, the articles’ bibliographies were consulted.

Results

Prevalence rates range from 3 to 98 %. This vast range can be explained partly by the differences in the selection criteria for the study sample and also the variety in diagnostic approaches or time frames. Women are slightly more affected than men and an age peak of 30–40 years has been reported. Still, the prevalence of erosions with dentin exposure seems to increase in younger adults, often resulting in hypersensitivity. In older patients, root surfaces are frequently exposed due to periodontal disease which is associated with a high rate of dentin hypersensitivity, especially after periodontal treatment and intensified brushing activity. On the other hand, the number of affected seniors with tooth loss or even edentulism is reduced. About 25–30 % of the adult population report dentin hypersensitivity. Most dentists also consider it to be a relevant problem in their practice, but they request more information on this topic. Maxillary teeth are affected to a higher extent, but the different teeth show very similar rates. Buccal surfaces clearly show the highest prevalence rates.

Conclusion

In spite of the advances regarding management of dentin hypersensitivity, it still remains an epidemiologically understudied field.

Clinical relevance

Although great variations have been observed in the prevalence of dentin hypersensitivity, this issue is often observed by dentists and related by patients. However, further studies are necessary to find the cause of this condition and refine its management.
Identification of leech embryonic neurons that express a Hox gene required for the differentiation of a paired, segment‐specific motor neuron
Authors: Gharbaran Rajendra , Aisemberg Gabriel O.
Published: December 2012

This study investigated the embryonic expression and function of the Hox gene Lox1 in the simple, well‐characterized central nervous system (CNS) of the medicinal leech Hirudo medicinalis. Lox1 was expressed in an anterior–posterior domain, extending from the posterior aspect of the fourth segment (rostral neuromere 4, R4) to the seventeenth segment (midbody ganglion 13, M13). Lox1 expression was also found in both sex organ primordia (male and female). Lox1 expression was not detected in every cell of the ganglia included in its domain. It was detected in a specific subset that included several segmentally iterated neurons and segment‐specific neurons. Several central neurons (neurons located in the central nervous system – CNS) that coexpressed both Lox1 and FMRFamide‐like peptides were identified using antibody staining of leech embryos and epifluorescence and confocal microscopy. RNA interference was used to block the expression of Lox1. The expression pattern and the effect of RNA interference indicate that Lox1 is required for the differentiation of a segment‐specific pair of motor neurons, the RPE (rostral penile evertor) neurons, which appear only in midbody ganglion 6 (M6) and innervate the male sex organ.
Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on attitudes towards dietary change
Authors: Anderson Annie S. , Cox David N. , McKellar Susan , Reynolds Joanna , Lean M. E. J. , Mela David J.
Published: December 2012

To assess the response of low consumers of fruit and vegetables to a nutrition education intervention programme, data were collected from 104 adults on attitudinal variables related to ‘eating more fruit, vegetables and vegetable dishes’. Questionnaires (based on the theory of planned behaviour) assessing perceived barriers to increasing fruit and vegetable consumption were administered before an action-orientated intervention programme and at the end of the intervention period (8 weeks). Questionnaire scores for belief-evaluations in the intervention groups pre- and post-study indicated that support of family and friends, food costs, time constraints and shopping practicalities (in order to increase intake of fruit, vegetable and vegetable dishes) were barriers to greater consumption of these foodstuffs. Perceived situational barriers to increasing intakes of fruits and vegetables were: limited availability of vegetables, salads and fruit at work canteens, take-aways, friends' houses and at work generally. Following the intervention the number of visits to the shops was perceived as a greater barrier for increasing intakes of fruit and vegetables. Perceived practical opportunities for increasing intakes highlighted drinking fruit juice, taking fruit as a dessert, having fruit as a between-meal snack and eating two portions of vegetables with a meal. About two-thirds of intervention subjects achieved the recommended fruit and vegetable target, but it is concluded that practical issues and situational barriers need to be addressed for the success of future public health campaigns.