bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal analysis and FT‐IR studies of adsorbed poly(ethylene‐stat‐vinyl acetate) on silica
Authors: Maddumaarachchi Madhubhashini , Blum Frank D.
Published: March 2014

Adsorbed poly(ethylene‐stat‐vinyl acetate) (PEVAc) on fumed silica was studied using temperature‐modulated differential scanning calorimetry (TMDSC) and FT‐IR spectroscopy. The properties of the copolymers were compared with poly(vinyl acetate) (PVAc) and low density polyethylene (LDPE) as references. TMDSC analysis of the copolymer‐silica samples in the glass transition region was complicated for the copolymers because of the ethylene crystallinity. Nevertheless, examination of the glass transition region for small adsorbed amounts of these copolymers indicated the presence of tightly‐ and loosely‐bound polymer segments, similar to other polymers which have an attraction to silica. Compared with bulk polymers with the same composition, the tightly‐bound polymers showed an increased glass transition temperature (Tg) and a loosely‐bound fraction with a lower Tg than bulk. FT‐IR spectra of the surface copolymers indicated that the fraction of bound carbonyls (p) increased as the fraction of vinyl acetate in the copolymers decreased, consistent with the notion that the carbonyls from vinyl acetate preferentially find their way to the silica surface. Spectra from samples with different adsorbed amounts of polymer were used to obtain the amount of bound polymer (Mb) and the ratio of molar absorption coefficients of bound carbonyls to free carbonyls (X). The copolymers had very large p values (up to 0.8) at small adsorbed amounts and dependent on the composition of the polymer. However, an analysis of the bound fractions, based on only the vinyl acetate groups, superimposed the data, suggesting that the ethylene units simply dilute the vinyl acetate groups in the surface polymer. The sample with the smallest fraction of vinyl acetate did not show this behavior and may be considered to be “carbonyl poor.” © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 727–736
The dynamic duo: Combining NMR and small angle scattering in structural biology
Authors: Hennig Janosch , Sattler Michael
Published: March 2014

Structural biology provides essential information for elucidating molecular mechanisms that underlie biological function. Advances in hardware, sample preparation, experimental methods, and computational approaches now enable structural analysis of protein complexes with increasing complexity that more closely represent biologically entities in the cellular environment. Integrated multidisciplinary approaches are required to overcome limitations of individual methods and take advantage of complementary aspects provided by different structural biology techniques. Although X‐ray crystallography remains the method of choice for structural analysis of large complexes, crystallization of flexible systems is often difficult and does typically not provide insights into conformational dynamics present in solution. Nuclear magnetic resonance spectroscopy (NMR) is well‐suited to study dynamics at picosecond to second time scales, and to map binding interfaces even of large systems at residue resolution but suffers from poor sensitivity with increasing molecular weight. Small angle scattering (SAS) methods provide low resolution information in solution and can characterize dynamics and conformational equilibria complementary to crystallography and NMR. The combination of NMR, crystallography, and SAS is, thus, very useful for analysis of the structure and conformational dynamics of (large) protein complexes in solution. In high molecular weight systems, where NMR data are often sparse, SAS provides additional structural information and can differentiate between NMR‐derived models. Scattering data can also validate the solution conformation of a crystal structure and indicate the presence of conformational equilibria. Here, we review current state‐of‐the‐art approaches for combining NMR, crystallography, and SAS data to characterize protein complexes in solution.
Ramachandran analysis of conserved glycyl residues in homologous proteins of known structure
Authors: Lakshmi Balasubramanian , Sinduja Chandrasekaran , Archunan Govind , Srinivasan Narayanaswamy
Published: March 2014

High conservation of glycyl residues in homologous proteins is fairly frequent. It is commonly understood that glycine tends to be highly conserved either because of its unique Ramachandran angles or to avoid steric clash that would arise with a larger side chain. Using a database of aligned 3D structures of homologous proteins we identified conserved Gly in 288 alignment positions from 85 families. Ninety‐six of these alignment positions correspond to conserved Gly residue with (φ, ψ) values allowed for non‐glycyl residues. Reasons for this observation were investigated by in‐silico mutation of these glycyl residues to Ala. We found in 94% of the cases a short contact exists between the Cβ atom of the introduced Ala with the atoms which are often distant in the primary structure. This suggests the lack of space even for a short side chain thereby explaining high conservation of glycyl residues even when they adopt (φ, ψ) values allowed for Ala. In 189 alignment positions, the conserved glycyl residues adopt (φ, ψ) values which are disallowed for Ala. In‐silico mutation of these Gly residues to Ala almost always results in steric hindrance involving Cβ atom of Ala as one would expect by comparing Ramachandran maps for Ala and Gly. Rare occurrence of the disallowed glycyl conformations even in ultrahigh resolution protein structures are accompanied by short contacts in the crystal structures and such disallowed conformations are not conserved in the homologues. These observations raise the doubt on the accuracy of such glycyl conformations in proteins.
Inhibition of the dorsomedial hypothalamus, but not the medullary raphe pallidus, decreases hyperthermia and mortality from MDMA given in a warm environment
Authors: Zaretsky Dmitry V. , Zaretskaia Maria V. , Durant Pamela J. , Rusyniak Daniel E.
Published: April 2014

The central mechanisms through which 3,4‐methylenedioxymethamphetamine (MDMA) mediates life‐threatening hyperthermia when taken in a warm environment are not well described. It is assumed that MDMA alters normal thermoregulatory circuits resulting in increased heat production through interscapular brown adipose tissue (iBAT) and decreased heat dissipation through cutaneous vasoconstriction. We studied the role of the dorsomedial hypothalamus (DMH) and medullary raphe pallidus (mRPa) in mediating iBAT, tail blood flow, and locomotor effects produced by MDMA. Rats were instrumented with guide cannulas targeting either the DMH or the mRPa brain regions involved in regulating iBAT and cutaneous vascular beds. In all animals, core temperature and locomotion were recorded with surgically implanted telemetric transmitters; additionally, either iBAT temperature (via telemetric transmitter) or tail artery blood flow (via tail artery Doppler cuff) were also recorded. Animals were placed in an environmental chamber at 32°C and microinjected with either control or the gamma‐aminobutyric acid (GABA) agonist muscimol (80 pmol) followed by an intravenous injection of saline or MDMA (7.5 mg kg−1). To prevent undue suffering, a core temperature of 41°C was chosen as the surrogate marker of mortality. Inhibition of the DMH, but not the mRPa, prevented mortality and attenuated hyperthermia and locomotion. Inhibition of either the DMH or the mRPa did not affect iBAT temperature increases or tail blood flow decreases. While MDMA increases iBAT thermogenesis and decreases heat dissipation through cutaneous vasoconstriction, thermoregulatory brain regions known to mediate these effects are not involved. Rather, the finding that inhibiting the DMH decreases both locomotion and body temperature suggests that locomotion may be a key central contributor to MDMA‐evoked hyperthermia.
Zonal mean circulations for two conserved meridional coordinates
Authors: Egger Joseph , Hoinka Klaus‐Peter
Published: March 2014

While many investigations of the atmospheric zonal mean circulation have been published using various vertical coordinates, this article concentrates on meridional coordinates other than latitude. Potential vorticity q and potential temperature θ are selected, with height as the vertical coordinate. Both q and θ are conserved in adiabatic frictionless flow. Although this helps in the interpretation of the results, both choices are problematic because of contortions in the contours. The related problems are solved by integrating over suitable zonal tubes.

The isertelic mean circulation exhibits global cells in the upper troposphere and separate shallow hemispheric cells near the ground. Mean q fluxes are derived from the mass circulation. The mean circulation in (θ,z) coordinates is similar to that in (ϕ,θ) coordinates and has hemispheric direct cells. Mean θ fluxes follow from that. Both circulations are forced, in the sense that they can be derived and understood if the zonal mean heating is known. This is demonstrated by explaining, for example, the equatorward surface flow in (θ,z) coordinates and the shallow boundary‐layer circulation in the isertelic system.
Clinical and molecular aspects of the live attenuated Oka varicella vaccine
Authors: Quinlivan Mark , Breuer Judy
Published: March 2014

VZV is a ubiquitous member of the Herpesviridae family that causes varicella (chicken pox) and herpes zoster (shingles). Both manifestations can cause great morbidity and mortality and are therefore of significant economic burden. The introduction of varicella vaccination as part of childhood immunization programs has resulted in a remarkable decline in varicella incidence, and associated hospitalizations and deaths, particularly in the USA. The vaccine preparation, vOka, is a live attenuated virus produced by serial passage of a wild‐type clinical isolate termed pOka in human and guinea pig cell lines. Although vOka is clinically attenuated, it can cause mild varicella, establish latency, and reactivate to cause herpes zoster. Sequence analysis has shown that vOka differs from pOka by at least 42 loci; however, not all genomes possess the novel vOka change at all positions, creating a heterogeneous population of genetically distinct haplotypes. This, together with the extreme cell‐associated nature of VZV replication in cell culture and the lack of an animal model, in which the complete VZV life cycle can be replicated, has limited studies into the molecular basis for vOka attenuation. Comparative studies of vOka with pOka replication in T cells, dorsal root ganglia, and skin indicate that attenuation likely involves multiple mutations within ORF 62 and several other genes. This article presents an overview of the clinical aspects of the vaccine and current progress on understanding the molecular mechanisms that account for the clinical phenotype of reduced virulence. Copyright © 2014 John Wiley & Sons, Ltd.
Surface characterization of polyvinylamine/SBA‐15 hybrid material
Authors: Wach Anna , Drozdek Marek , Dudek Barbara , Kuśtrowski Piotr
Published: March 2014

The surface of mesoporous silica (SBA‐15) was functionalized by an introduction of polymer containing amine groups. The proposed, novel modification route consisted of three main stages including: (i) grafting of vinyltriethoxysilane (VTS) on the surface silanols, (ii) radical copolymerization of grafted VTS with N‐vinylformamide and (iii) acid hydrolysis of poly(N‐vinylformamide) (PNVF) to poly(vinylamine). The SBA‐15 structure remained stable during all the modification steps as confirmed by X‐ray powder diffraction and low‐temperature N2 adsorption. Changes in the surface composition were studied by elemental analysis and thermogravimetry, whereas the nature of surface species was identified by diffuse reflectance infrared Fourier transform and X‐ray photoelectron spectroscopy. The optimal amount of introduced PNVF, which allowed to obtain the highest dispersion of amine functionalities and protect the pore system of mesoporous support against total blocking by the formed polymer, was determined. Copyright © 2014 John Wiley & Sons, Ltd.
Structural studies on Si‐N gradient thin layers by grazing incidence X‐ray diffraction
Authors: Karolus Malgorzata
Published: March 2014

In this paper, the application of combined method – the powerful tool for structure analysis – used for the structure determination of non‐ordered gradient Si‐N thin films is presented. The method is based on the combination of well‐known methods, like radial distribution function (RDF), pair distribution function (PDF) analyses and the Rietveld refinement. The values of radii and number of coordination spheres, obtained from RDF and PDF analyses, were compared to the theoretical values calculated for typical crystalline structures. Then, the most probable model of the hypothetical ‘unit cell’ of the analysed material might be chosen for the Rietveld refinement. In case of the gradient materials and thin films, the structure analysis is more complicated because the experiment has to be prepared in grazing incident X‐ray diffraction geometry. The X‐ray diffraction patterns collected for different angles of the incident beam show different shape, what indicate different kind of order in layers. Finally, it was stated that the Si‐N layers are nonhomogenous, and their structure depends on the penetration depth. Moreover, there was a possibility to create the complete structure model of whole gradient Si‐N thin film. Copyright © 2014 John Wiley & Sons, Ltd.
The effect of the substrate on thermal stability of CeOx and Rh–Ce–O thin films
Authors: Ševčíková Klára , Nehasil Václav , Zahoranová Tatiana , Vorokhta Mykhaylo , Tsud Nataliya , Yoshikawa Hideki , Kobata Masaaki , Kobayashi Keisuke , Matolín Vladimír
Published: March 2014

Cerium oxide doped by a noble metal has been researched intensively for its high catalytic activity. In the presented study, Rh–Ce–O and CeOx thin films were deposited onto SiO2 and Cu substrates by radio‐frequency magnetron sputtering. Thermal stability of the films was investigated by photoelectron spectroscopy techniques. Our results show that the substrate has a great influence on the stability of the overlayers. Rh–Ce–O deposited on Cu decomposes into rhodium and cerium oxide separate phases above 600 K. In contrary, the Rh–Ce–O film on SiO2 remains stable up to 800 K, but silicon migrates from the substrate into the film, forming cerium silicate. We suggest that a strong interaction between SiO2 substrate and Rh–Ce–O, or CeOx films, could be responsible for higher thermal stability compared to films deposited onto Cu. Copyright © 2014 John Wiley & Sons, Ltd.
Public engagement with offshore renewable energy: a critical review
Authors: Wiersma Bouke , Devine‐Wright Patrick
Published: March 2014

Offshore renewable energy, including offshore wind, tidal and wave energy, has sometimes been represented as opposition‐free alternatives to controversial technologies such as onshore wind turbines, and has received increasing attention from social scientists in recent years. A fragmented literature has emerged investigating public engagement with these technologies and the determinants of public acceptance, comprising 59 key studies—the majority investigating offshore wind energy (59%). This literature review argues that while the ways in which public actors engage with offshore renewable energy are to some extent similar to onshore energy infrastructure, there are also important differences. These include the generally lower levels of public knowledge about the technologies, a changing role for visual impacts, a fundamentally different, marine, spatial context, and different sets of stakeholders in different decision‐making arenas. There is a need to explore as yet unasked and unanswered questions—going beyond ‘established’ variables identified in the onshore wind‐based ‘beyond NIMBY’ literature—especially regarding the role of the marine location of these technologies, and the cross‐technology and cross‐disciplinary applicability of findings. In order to more fully understand public responses to energy infrastructures, future research needs to move beyond case studies of onshore wind developments, adopting more diverse and ambitious research designs and methodologies.

This article is categorized under:

Perceptions, Behavior, and Communication of Climate Change > Behavior Change and Responses
The Revised World Medical Association's Declaration of Helsinki 2013: Enhancing the Protection of Human Research Subjects and Empowering Ethics Review Committees
Authors: Nicogossian Arnauld , Kloiber Otmar , Stabile Bonnie
Published: March 2014

A reflection on the World Medical Association's recent revision of the Declaration of Helsinki.
Haitian Attitudes Toward Acute Febrile Illness: Public Health Insights From a Narrative Perspective
Authors: Chan Carolyn A.
Published: March 2014

This is the tale of a Haitian woman's attitudes towards acute febrile illness in post‐earthquake Haiti and a medical student's insights into public health gained by viewing a data set within a narrative.
Promoting to Everyone, Focusing on No One: The Illogical Promotion of the Influenza Vaccine
Authors: Richards Carly Noel , Tran Christine , Fugh‐Berman Adriane
Published: March 2014

In 2010, the Centers for Disease Control and Prevention (CDC) expanded guidelines for annual influenza vaccine to recommend universal vaccination of everyone over the age of 6 months. In 2007, the CDC partnered with Families Fighting Flu, an industry‐funded group, to create public service announcements promoting vaccination of healthy children, the segment of the population at the least risk of dying. The “everyone is at risk” message associated with universal influenza vaccination could undermine effective influenza prevention efforts. Most influenza‐related deaths and hospitalizations occur in those aged 85 and older—a population in which influenza vaccine is not very effective. Herd immunity, integral to the effectiveness of other vaccines, is difficult to achieve with influenza vaccine, which is less effective than other vaccines, and must be given annually. Controlling pandemic or non‐pandemic influenza may depend not only on vaccination but also on social distancing, handwashing, and wearing masks. Non‐vaccine infection control techniques may work against influenza and other respiratory infections. Comparative effectiveness research is needed to determine the best methods for reducing deaths and hospitalizations for influenza and pneumonia. Discussion is needed about the extent to which public health recommendations are distorted by industry relationships. Public health messaging must be evidence‐based.
MicroRNAs as therapeutic targets in human cancers
Authors: Shah Maitri Y. , Calin George A.
Published: March 2014

MicroRNAs (miRNAs) are evolutionarily conserved, small, regulatory RNAs that negatively regulate gene expression. Extensive research in the last decade has implicated miRNAs as master regulators of cellular processes with essential role in cancer initiation, progression, and metastasis, making them promising therapeutic tools for cancer management. In this article, we will briefly review the structure, biogenesis, functions, and mechanism of action of these miRNAs, followed by a detailed analysis of the therapeutic potential of these miRNAs. We will focus on the strategies presently used for miRNA therapy; discuss their use and drawbacks; and the challenges and future directions for the development of miRNA‐based therapy for human cancers. WIREs RNA 2014, 5:537–548. doi: 10.1002/wrna.1229

This article is categorized under:

RNA in Disease and Development > RNA in Disease

RNA in Disease and Development > RNA in Development
Physiological networks and disease functions of RNA‐binding protein AUF1
Authors: Moore Ashleigh E. , Chenette Devon M. , Larkin Lauren C. , Schneider Robert J.
Published: March 2014

Regulated messenger RNA (mRNA) decay is an essential mechanism that governs proper control of gene expression. In fact, many of the most physiologically potent proteins are encoded by short‐lived mRNAs, many of which contain AU‐rich elements (AREs) in their 3′‐untranslated region (3′‐UTR). AREs target mRNAs for post‐transcriptional regulation, generally rapid decay, but also stabilization and translation inhibition. AREs control mRNA turnover and translation activities through association with trans‐acting RNA‐binding proteins that display high affinity for these AU‐rich regulatory elements. AU‐rich element RNA‐binding protein (AUF1), also known as heterogeneous nuclear ribonucleoprotein D (HNRNPD), is an extensively studied AU‐rich binding protein (AUBP). AUF1 has been shown to regulate ARE‐mRNA turnover, primarily functioning to promote rapid ARE‐mRNA degradation. In certain cellular contexts, AUF1 has also been shown to regulate gene expression at the translational and even the transcriptional level. AUF1 comprises a family of four related protein isoforms derived from a common pre‐mRNA by differential exon splicing. AUF1 isoforms have been shown to display multiple and distinct functions that include the ability to target ARE‐mRNA stability or decay, and transcriptional activation of certain genes that is controlled by their differential subcellular locations, expression levels, and post‐translational modifications. AUF1 has been implicated in controlling a variety of physiological functions through its ability to regulate the expression of numerous mRNAs containing 3′‐UTR AREs, thereby coordinating functionally related pathways. This review highlights the physiological functions of AUF1‐mediated regulation of mRNA and gene expression, and the consequences of deficient AUF1 levels in different physiological settings. WIREs RNA 2014, 5:549–564. doi: 10.1002/wrna.1230

This article is categorized under:

RNA Interactions with Proteins and Other Molecules > RNA–Protein Complexes

RNA Turnover and Surveillance > Regulation of RNA Stability

RNA in Disease and Development > RNA in Disease
High-level production of Fc-fused kringle domain in Pichia pastoris
Authors: Jeong Gu Min , Lee Yong Jae , Kim Yong Sung , Jeong Ki Jun
Published: March 2014

Recently, as a new non-immunoglobulin-based protein scaffold, a human kringle domain was successfully engineered toward biologically functional agonists and antagonists. In this study, the fed-batch cultivation conditions were optimized for enhanced production of an Fc-fused kringle domain (KD548-Fc) in Pichia pastoris. Fed-batch cultivations were performed in 5-l laboratory-scale bioreactors, and in order to find the optimal conditions for high-level production of KD548-Fc, several parameters including the initial carbon source (glycerol) concentration, temperature, and pH were investigated. When cells were cultivated at pH 4.0 and 25 °C with 9.5 % glycerol in the initial medium, the highest production yield (635 mg/l) was achieved with high productivity (7.2 mg/l/h). Furthermore, functional KD548-Fc was successfully purified from the culture broth using a simple purification procedure with high purity and recovery yield.
Partial Likelihood Estimation of IRT Models with Censored Lifetime Data: An Application to Mental Disorders in the ESEMeD Surveys
Authors: Forero Carlos G. , Almansa Josué , Adroher Núria D. , Vermunt Jeroen K. , Vilagut Gemma , De Graaf Ron , Haro Josep-Maria , Alonso Caballero Jordi
Published: March 2014

Developmental studies of mental disorders based on epidemiological data are often based on cross-sectional retrospective surveys. Under such designs, observations are right-censored, causing underestimation of lifetime prevalences and correlations, and inducing bias in latent trait models on the observations. In this paper we propose a Partial Likelihood (PL) method to estimate unbiased IRT models of lifetime predisposition to develop a certain outcome. A two-step estimation procedure corrects the IRT likelihood of outcome appearance with a function depending on (a) projected outcome frequencies at the end of the risk period, and (b) outcome censoring status at the time of the observation. Simulation results showed that the PL method yielded good recovery of true frequencies and intercepts. Slopes were best estimated when events were sufficiently correlated. When PL is applied to lifetime mental health disorders (assessed in the ESEMeD project surveys), estimated univariate prevalences were, on average, 1.4 times above raw estimates, and 2.06 higher in the case of bivariate prevalences.
Evaluando las intervenciones cambiarias en Colombia: 2004-2012
Authors: Lopera Mauricio , Mesa Ramón Javier , Londoño Charle
Published: March 2014

Esta investigación tiene como propósito evaluar la efectividad de las intervenciones en el mercado cambiariocolombiano, utilizando el modelo teórico canal de coordinación bajo la metodología red neuronalde regresión cuantil. Con este objetivo se estima el efecto de los inversionistas no informados, informadosy el emisor en diferentes cuantiles de la distribución del retorno de la tasa de cambio en el largoplazo. Se encuentra que la autoridad cambiaria tiene una mayor influencia en los cuantiles inferiores dela distribución, como son los de 5 y 25%, que recogen efectos asociados con la revaluación del peso.
The Clouston syndrome mutation connexin30 A88V leads to hyperproliferation of sebaceous glands and hearing impairments in mice
Authors: Bosen Felicitas , Schütz Melanie , Beinhauer Anna , Strenzke Nicola , Franz Thomas , Willecke Klaus
Published: March 2014

Distinct mutations in the gap junction protein connexin30 (Cx30) can cause the ectodermal dysplasia Clouston syndrome in humans. We have generated a new mouse line expressing the Clouston syndrome mutation Cx30A88V under the control of the endogenous Cx30 promoter. Our results show that the mutated Cx30A88V protein is incorporated in gap junctional plaques of the epidermis. Homozygous Cx30A88V mice reveal hyperproliferative and enlarged sebaceous glands as well as a mild palmoplantar hyperkeratosis. Additionally, homozygous mutant mice show an altered hearing profile compared to control mice. We conclude that the Cx30A88V mutation triggers hyperproliferation in the skin and changes the cochlear homeostasis in mice.
Interaction of Sesbania mosaic virus (SeMV) RNA‐dependent RNA polymerase (RdRp) with the p10 domain of polyprotein 2a and its implications in SeMV replication
Authors: Govind Kunduri , Bakshi Arindam , Savithri Handanahal S.
Published: March 2014

Identification of viral encoded proteins that interact with RNA‐dependent RNA polymerase (RdRp) is an important step towards unraveling the mechanism of replication. Sesbania mosaic virus (SeMV) RdRp was shown to interact strongly with p10 domain of polyprotein 2a and moderately with the protease domain. Mutational analysis suggested that the C‐terminal disordered domain of RdRp is involved in the interaction with p10. Coexpression of full length RdRp and p10 resulted in formation of RdRp–p10 complex which showed significantly higher polymerase activity than RdRp alone. Interestingly, CΔ43 RdRp also showed a similar increase in activity. Thus, p10 acts as a positive regulator of RdRp by interacting with the C‐terminal disordered domain of RdRp.
Long‐term effect of cardiac pacing on sleep‐disordered breathing in patients with conventional indications for a permanent pacemaker
Authors: Matsushita Kohei , Ishikawa Toshiyuki , Toda Noritaka , Sumita Shinnichi , Matsumoto Katsumi , Hosoda Junya , Kimura Yuuichirou , Ogino Yutaka , Taguchi Yuka , Ishigami Tomoaki , Sugano Teruyasu , Umemura Satoshi
Published: March 2014

Background

The effect of cardiac pacing on sleep‐disordered breathing is controversial. We investigated the long‐term effect of cardiac pacing on sleep disordered breathing in patients with conventional indications for permanent pacemakers

Methods

Subjects comprised 40 patients (29 men; mean age 69±9 years, mean left ventricle ejection fraction 69±8%, and body mass index 23.6±3.5 kg/m2) who were diagnosed with indications for permanent pacemakers (sick sinus syndrome in 23 patients, atrioventricular block in 15, and brady atrial fibrillation in 2). All patients received polysomnographic evaluations before implantation of permanent pacemakers. After implantation of permanent pacemakers, all patients received polysomnographic evaluations during use of the pacemaker settings (AAI/DDD/VVI at 70 beats per minute).

Results

The mean follow‐up period was 35±13 months. Before implantation, the distribution of sleep‐disordered breathing was as follows: 93% had apnea hypopnea index >5, 58% had apnea hypopnea index >15, and 20% had apnea hypopnea index >30. The mean apnea hypopnea index for all patients was 20±15, for those with obstructive type apnea was 4.9±5.3, and for those with central type apnea was 3.0±4.5. The mean Epworth Sleepiness Score was 5.9±4.0. No patient received continuous positive airway pressure therapy or any other therapy for sleep‐disordered breathing during the follow up period. The mean apnea hypopnea index at 1 week after implantation of permanent pacemakers was 21±14 (P=0.8) and the mean apnea hypopnea index at end of follow‐up was 11±7 (P<0.0001).

Conclusion

Long term cardiac pacing significantly reduces the number of episodes of sleep apnea in patients with conventional permanent pacemaker indications.
A late Holocene paleoenvironmental reconstruction from Agua Caliente, southern Belize, linked to regional climate variability and cultural change at the Maya polity of Uxbenká
Authors: Walsh Megan K. , Prufer Keith M. , Culleton Brendan J. , Kennett Douglas J.
Published: March 2014

We report high-resolution macroscopic charcoal, pollen and sedimentological data for Agua Caliente, a freshwater lagoon located in southern Belize, and infer a late Holocene record of human land-use/climate interactions for the nearby prehistoric Maya center of Uxbenká. Land-use activities spanning the initial clearance of forests for agriculture through the drought-linked Maya collapse and continuing into the historic recolonization of the region are all reflected in the record. Human land alteration in association with swidden agriculture is evident early in the record during the Middle Preclassic starting ca. 2600 cal yr BP. Fire slowly tapered off during the Late and Terminal Classic, consistent with the gradual political demise and depopulation of the Uxbenká polity sometime between ca. 1150 and 950 cal yr BP, during a period of multiple droughts evident in a nearby speleothem record. Fire activity was at its lowest during the Maya Postclassic ca. 950–430 cal yr BP, but rose consistent with increasing recolonization of the region between ca. 430 cal yr BP and present. These data suggest that this environmental record provides both a proxy for 2800 years of cultural change, including colonization, growth, decline, and reorganization of regional populations, and an independent confirmation of recent paleoclimate reconstructions from the same region.
Non-existence of three-dimensional travelling water waves with constant non-zero vorticity
Authors: Wahlén E.
Published: April 2014

We prove that there are no three-dimensional bounded travelling gravity waves with constant non-zero vorticity on water of finite depth. The result also holds for gravity–capillary waves under a certain condition on the pressure at the surface, which is satisfied by sufficiently small waves. The proof relies on unique continuation arguments and Liouville-type results for elliptic equations.
Metal–organic frameworks as heterogeneous photocatalysts: advantages and challenges
Authors: Nasalevich M. A. , van der Veen M. , Kapteijn F. , Gascon J.
Published: April 2014

The use of metal organic frameworks as photocatalysts is critically reviewed and their main advantages and challenges are evaluated.
Catalytic nanomotors for environmental monitoring and water remediation
Authors: Soler Lluís , Sánchez Samuel
Published: April 2014

Self-propelled nanomotors hold considerable promise for developing innovative environmental applications.
Synthesis of alkynyl/alkenyl-substituted pyridine derivatives via heterocyclization and Pd-mediated Sonogashira/Heck coupling process in one-pot: a new MCR strategy
Authors: Bodireddy Mohan Reddy , Reddy N. C. Gangi , Kumar Sangita D.
Published: March 2014

The present MCR strategy opens new avenues in the development of i) a diversity-oriented new cyanopyridine based compound library and ii) new chemical entities other than the present reported molecules.
Solid state structural transformation of bromide coordination polymer to chloride by anion replacement; new precursors for preparation of PbBr2 and PbCl2 nanoparticles
Authors: Hashemi Lida , Morsali Ali
Published: March 2014

Reversible anion-exchange of 2D lead(ii) coordination polymers from [Pb(4-bpdb)Br2]n (1) to [Pb(4-bpdb)Cl2]n (2) by solid state anion-replacement has been studied.
Development of anticorrosive two pack polyurethane coatings based on modified fatty amide of Azadirachta indica Juss oil cured at room temperature – a sustainable resource
Authors: Chaudhari Ashok , Kuwar Anil , Mahulikar Pramod , Hundiwale Dilip , Kulkarni Ravindra , Gite Vikas
Published: March 2014

We report the modification ofAzadirachta indicaJuss oil (renewable source) fatty amide by the piperazine molecule to develop a new polyol.
A high-performance polyurethane sponge for the detection, adsorption and separation of Cu2+ ions
Authors: Yu Yun , Wang Jianrui , Lian Jiansheng , Cheng Xinjian
Published: March 2014

A small chemosensor, 2-(2-hydroxy-ethyl)-6-(quinolin-8-ylamino)-benzo[de]isoquinoline-1,3-dione was firstly synthesized and then was introduced into a PU sponge. The as-prepared sponge showed excellent ability to detect and remove Cu2+ ions.
A novel structured catalyst: gold supported on thin bimetallic (Ni, Co) carbonate hydroxide nanosheet arrays
Authors: Liu Wenxian , Weng Xiwen , Yang Qiu , Li Tian , Liu Junfeng , Sun Xiaoming
Published: April 2014

A novel structured catalyst, Au/bimetallic (Ni, Co) carbonate hydroxide nanosheet arrays, supported on a three-dimensional substrate were prepared, which exhibited excellent catalytic activity for the reduction of 4-nitrophenol (4-NP).
Exceeding the filling fraction limit in CoSb3 skutterudite: multi-role chemistry of praseodymium leading to promising thermoelectric performance
Authors: Graff J. W. , Zeng X. , Dehkordi A. M. , He J. , Tritt T. M.
Published: April 2014

Purposefully exceeding the FFL of the previously uninvestigated Pr-filled Co4Sb12 system resulting in state-of-the-art thermoelectric properties for the single-filled skutterudite.
Toward fully organic rechargeable charge storage devices based on carbon electrodes grafted with redox molecules
Authors: Lebègue Estelle , Brousse Thierry , Gaubicher Joël , Retoux Richard , Cougnon Charles
Published: April 2014

We present a fully organic rechargeable charge storage device based on carbon electrodes grafted with redox molecules providing combined performance of electrochemical capacitors and batteries.
Abinitio thermodynamic model of Cu2ZnSnS4
Authors: Jackson Adam J. , Walsh Aron
Published: April 2014

The formation and decomposition of Cu2ZnSnS4 (CZTS), a quaternary semiconductor and promising photovoltaic absorber, is modelled as a function of temperature and pressure by ab initio methods.
An electrochemiluminescence biosensor for sensitive and selective detection of Hg2+based on π–π interaction between nucleotides and ferrocene–graphene nanosheets
Authors: Zhuo Bangrong , Li Yuqin , Zhang An , Lu Fushen , Chen Yaowen , Gao Wenhua
Published: April 2014

An electrochemiluminescence biosensor with the quenching pattern of ferrocene–graphene to Ru(bpy)32+workingviaπ–π interaction between nucleotides and ferrocene–graphene, and the detection limit of Hg2+is 18 pM.
High-performance ZnO/Ag Nanowire/ZnO composite film UV photodetectors with large area and low operating voltage
Authors: Yang Zhi , Wang Minqiang , Song Xiaohui , Yan Guodong , Ding Yucheng , Bai Jinbo
Published: April 2014

We have demonstrated that the embedded Ag nanowire network plays the important role of greatly improving responsivity and shortening response time in ZnO/Ag nanowires/ZnO composite uv photodetector.
Two-dimensional Fourier transform electronic spectroscopy at a conical intersection
Authors: Kitney-Hayes Katherine A. , Ferro Allison A. , Tiwari Vivek , Jonas David M.
Published: March 2014

We report measurement and modeling of two-dimensional (2D) electronic spectra of a silicon naphthalocyanine (SiNc) in benzonitrile, a system for which the polarization anisotropy reveals passage through a square-symmetric Jahn-Teller conical intersection in ∼100 fs [D. A. Farrow, W. Qian, E. R. Smith, A. A. Ferro, and D. M. Jonas, J. Chem. Phys. 128, 144510 (2008)]. The measured 2D Fourier transform (FT) spectra indicate loss of electronic coherence on a similar timescale. The 2D spectra arising from femtosecond vibronic dynamics through the conical funnel are modeled by full non-adiabatic treatment of the coupled electronic and vibrational dynamics for a pair of un-damped Jahn-Teller active vibrations responsible for both electronic decoherence and population transfer. Additional damped Jahn-Teller active modes that can cause only decoherence or population transfer are treated with analytical response functions that can be incorporated into the numerical non-adiabatic calculation by exploiting symmetry assignment of degenerate vibronic eigenstates to one of two electronic states. Franck-Condon active totally symmetric modes are incorporated analytically. The calculations reveal that these conical intersection dynamics alone are incapable of destroying the coherence of the initially prepared wavepacket on the experimentally observed timescale and predict an unobserved recurrence in the photon echo slice at ∼200 fs. Agreement with the experimental two-dimensional electronic spectra necessitates a role for totally symmetric vibrational dynamics in causing the echo slice to decay on a ∼100 fs timescale. This extended model also reproduces the ∼100 fs ultrafast electronic anisotropy decay in SiNc when an “asymmetric solvation mode” with a small stabilization energy of ∼2 cm−1 is included. Although calculations show that inhomogeneities in the energy gap between excited states can broaden the anti-diagonal 2D lineshape, the anti-diagonal width is dominated by totally symmetric vibrational motions in SiNc. For this shallow conical intersection, the non-adiabatic dynamics destroy electronic coherence more slowly than they destroy electronic alignment.
Specific heat mechanism of molten salt nanofluids
Authors: Shin D. , Tiznobaik H. , Banerjee D.
Published: March 2014

Controversial results have been reported for specific heat of conventional nanofluids and molten salt nanofluids. Some water-based and organic-based nanofluids showed decreases in specific heat, while molten salt-based nanofluids showed highly enhanced specific heat. In this study, we propose a distinct heat storage mechanism to explain enhanced specific heat of molten salt nanofluids and compare with the specific heat mechanism of conventional nanofluids.
Electrochemical deposition of iron sulfide thin films and heterojunction diodes with zinc oxide
Authors: Kawai Shoichi , Yamazaki Ryuta , Sobue Susumu , Okuno Eiichi , Ichimura Masaya
Published: March 2014

Iron sulfide thin films were fabricated by the electrochemical deposition method from an aqueous solution containing FeSO4 and Na2S2O3. The composition ratio obtained was Fe:S:O = 36:56:8. In the photoelectrochemical measurement, a weak negative photo-current was observed for the iron sulfide films, which indicates that its conduction type is p-type. No peaks were observed in X-ray diffraction pattern, and thus the deposited films were considered to be amorphous. For a heterojunction with ZnO, rectification properties were confirmed in the current-voltage characteristics. Moreover, the current was clearly enhanced under AM1.5 illumination.
Cluster formation in fluids with competing short-range and long-range interactions
Authors: Sweatman Martin B. , Fartaria Rui , Lue Leo
Published: March 2014

We investigate the low density behaviour of fluids that interact through a short-ranged attraction together with a long-ranged repulsion (SALR potential) by developing a molecular thermodynamic model. The SALR potential is a model of effective solute interactions where the solvent degrees of freedom are integrated-out. For this system, we find that clusters form for a range of interaction parameters where attractive and repulsive interactions nearly balance, similar to micelle formation in aqueous surfactant solutions. We focus on systems for which equilibrium behaviour and liquid-like clusters (i.e., droplets) are expected, and find in addition a novel coexistence between a low density cluster phase and a high density cluster phase within a very narrow range of parameters. Moreover, a simple formula for the average cluster size is developed. Based on this formula, we propose a non-classical crystal nucleation pathway whereby macroscopic crystals are formed via crystal nucleation within microscopic precursor droplets. We also perform large-scale Monte Carlo simulations, which demonstrate that the cluster fluid phase is thermodynamically stable for this system.
Optimization of the post-sintering annealing condition for the high Cu content Nd-Fe-B sintered magnet
Authors: Kim Tae-Hoon , Lee Seong-Rae , Woo Kim Jin , Do Kim Young , Kim Hyo-Jun , Lee Min-Woo , Jang Tae-Suk
Published: March 2014

We investigated the changes in microstructure and magnetic properties of Nd–Fe–B magnets as a function of Cu content (Cu addition in the range of 0.2–0.5 at. %). We have focused on the phase-transformation temperature of the Nd-rich phases in dependence of the Cu content. The coercivity of the magnets decreased (from 28.7 kOe to 27.1 kOe) on increasing Cu content under identical post-sintering annealing (PSA) conditions. The Cu-enriched C-Nd2O3 triple junction phase (TJP) and grain boundary phase (GBP) were observed in the 0.2 at. % Cu-containing magnet. However, in the 0.5 at. % Cu-containing magnet, the Cu-enriched TJP and GBP appeared in the form of the h-Nd2O3 phase that could be transformed into the C-Nd2O3 phase by a modified 1st-PSA temperature. The coercivity of the 0.5 at. % Cu-containing magnet was noticeably enhanced (from 27.1 kOe to 29.4 kOe).
Electronic quantum effects mapped onto non-Born-Oppenheimer nuclear paths: Nonclassical surmounting over potential barriers and trapping above the transition states due to nonadiabatic path-branching
Authors: Yamamoto Kentaro , Takatsuka Kazuo
Published: March 2014

We develop the path-branching representation for nonadiabatic electron wavepacket dynamics [T. Yonehara and K. Takatsuka, J. Chem. Phys. 132, 244102 (2010)] so as to treat dynamics in an energy range comparable to the barrier height of adiabatic potential energy curves. With this representation two characteristic chemical reaction dynamics are studied, in which an incident nuclear wavepacket encounters a potential barrier, on top of which lies another nonadiabatically coupled adiabatic potential curve: (1) Dynamics of initial paths coming into the nonadiabatic interaction region with energy lower than the barrier height. They branch into two pieces (and repeat branching subsequently), the upper counterparts of which can penetrate into a classically inaccessible high energy region and eventually branch back to the product region on the ground state curve. This is so to say surmounting the potential barrier via nonadiabatically coupled excited state, and phenomenologically looks like the so-called deep tunneling. (2) Dynamics of classical paths whose initial energies are a little higher than the barrier but may be lower than the bottom of the excited state. They can undergo branching and some of those components are trapped on top of the potential barrier, being followed by the population decay down to the lower state flowing both to product and reactant sites. Such expectations arising from the path-branching representation are numerically confirmed with full quantum mechanical wavepacket dynamics. This phenomenon may be experimentally observed as time-delayed pulses of wavepacket trains.
Stretching of single poly-ubiquitin molecules revisited: Dynamic disorder in the non-exponential unfolding kinetics
Authors: Zheng Yue , Bian Yukun , Zhao Nanrong , Hou Zhonghuai
Published: March 2014

A theoretical framework based on a generalized Langevin equation (GLE) with fractional Gaussian noise (fGn) and a power-law memory kernel is presented to describe the non-exponential kinetics of the unfolding of a single poly-ubiquitin molecule under a constant force [T.-L. Kuo, S. Garcia-Manyes, J. Li, I. Barel, H. Lu, B. J. Berne, M. Urbakh, J. Klafter, and J. M. Fernández, Proc. Natl. Acad. Sci. U.S.A. 107, 11336 (2010)]. Such a GLE-fGn strategy is made on the basis that the pulling coordinate variable x undergoes subdiffusion, usually resulting from conformational fluctuations, over a one-dimensional force-modified free-energy surface U(x, F). By using the Kramers’ rate theory, we have obtained analytical formulae for the time-dependent rate coefficient k(t, F), the survival probability S(t, F) as well as the waiting time distribution function f(t, F) as functions of time t and force F. We find that our results can fit the experimental data of f(t, F) perfectly in the whole time range with a power-law exponent γ = 1/2, the characteristic of typical anomalous subdiffusion. In addition, the fitting of the survival probabilities for different forces facilitates us to reach rather reasonable estimations for intrinsic properties of the system, such as the free-energy barrier and the distance between the native conformation and the transition state conformation along the reaction coordinate, which are in good agreements with molecular dynamics simulations in the literatures. Although static disorder has been implicated in the original work of Kuo et al., our work suggests a sound and plausible alternative interpretation for the non-exponential kinetics in the stretching of poly-ubiquitin molecules, associated with dynamic disorder.
Electrical activity of the Hartmann layers relative to surface viscous shearing in an annular magnetohydrodynamic flow
Authors: Delacroix Jules , Davoust Laurent
Published: March 2014

As a first step towards two-phase magnetohydrodynamics (MHD), this paper addresses an original analytical coupling between surface rheology, e.g., a gradually oxidizing liquid metal surface, ruled by the Boussinesq number Bo, and a supporting annular MHD flow, ruled by the Hartmann number Ha, in the general layout of a classical annular deep-channel viscometer, as developed by Mannheimer and Schechter [J. Colloid Interface Sci. 32, 195–211 (1970)]. Using a matched asymptotic expansion based on the small parameter 1/Ha, we can express the surface velocity as a coupling variable in the jump momentum balance at the liquid surface. By solving the latter through the determination of the Green's function, the whole flow can be analytically calculated. A modified Boussinesq number, \documentclass[12pt]{minimal}\begin{document}$\tilde{B_o}$\end{document}Bõ, is produced as a new non-dimensional parameter that provides the balance between surface viscous shearing and the Lorentz force. It is shown that the \documentclass[12pt]{minimal}\begin{document}$\tilde{B_o}$\end{document}Bõ number drives the electrical activation of the Hartmann layers, heavily modifying the MHD flow topology and leading to the emergence of the Lorentz force, for which interaction with the flow is not classical. Finally, the evolution laws given in this study allow the determination of scaling laws for an original experimental protocol, which would make it possible to accurately determine the surface shear viscosity of a liquid metal with respect to the quality of the ambient atmosphere.