bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of novel bacteriophage phiC119 capable of lysing multidrug-resistant Shiga toxin-producingEscherichia coliO157:H7
Authors: Amarillas Luis , Chaidez Cristóbal , González-Robles Arturo , Lugo-Melchor Yadira , León-Félix Josefina
Published: September 2016

Background

Shiga toxin-producingEscherichia coli(STEC) is one of the most common and widely distributed foodborne pathogens that has been frequently implicated in gastrointestinal and urinary tract infections. Moreover, high rates of multiple antibiotic-resistantE. colistrains have been reported worldwide. Due to the emergence of antibiotic-resistant strains, bacteriophages are considered an attractive alternative to biocontrol pathogenic bacteria. Characterization is a preliminary step towards designing a phage for biocontrol.

Methods

In this study, we describe the characterization of a bacteriophage designated phiC119, which can infect and lyse several multidrug-resistant STEC strains and someSalmonellastrains. The phage genome was screened to detect thestx-genes using PCR, morphological analysis, host range was determined, and genome sequencing were carried out, as well as an analysis of the cohesive ends and identification of the type of genetic material through enzymatic digestion of the genome.

Results

Analysis of the bacteriophage particles by transmission electron microscopy showed that it had an icosahedral head and a long tail, characteristic of the familySiphoviridae. The phage exhibits broad host range against multidrug-resistant and highly virulentE. coliisolates. One-step growth experiments revealed that the phiC119 phage presented a large burst size (210 PFU/cell) and a latent period of 20 min. Based on genomic analysis, the phage contains a linear double-stranded DNA genome with a size of 47,319 bp. The phage encodes 75 putative proteins, but lysogeny and virulence genes were not found in the phiC119 genome.

Conclusion

These results suggest that phage phiC119 may be a good biological control agent. However, further studies are required to ensure its control of STEC and to confirm the safety of phage use.
Comparative cephalopod shell strength and the role of septum morphology on stress distribution
Authors: Lemanis Robert , Zachow Stefan , Hoffmann René
Published: September 2016

The evolution of complexly folded septa in ammonoids has long been a controversial topic. Explanations of the function of these folded septa can be divided into physiological and mechanical hypotheses with the mechanical functions tending to find widespread support. The complexity of the cephalopod shell has made it difficult to directly test the mechanical properties of these structures without oversimplification of the septal morphology or extraction of a small sub-domain. However, the power of modern finite element analysis now permits direct testing of mechanical hypothesis on complete, empirical models of the shells taken from computed tomographic data. Here we compare, for the first time using empirical models, the capability of the shells of extantNautilus pompilius,Spirula spirula, and the extinct ammoniteCadocerassp. to withstand hydrostatic pressure and point loads. Results show hydrostatic pressure imparts highest stress on the final septum with the rest of the shell showing minimal compression.S. spirulashows the lowest stress under hydrostatic pressure whileN. pompiliusshows the highest stress.Cadocerassp. shows the development of high stress along the attachment of the septal saddles with the shell wall. Stress due to point loads decreases when the point force is directed along the suture as opposed to the unsupported chamber wall.Cadocerassp. shows the greatest decrease in stress between the point loads compared to all other models. Greater amplitude of septal flutes corresponds with greater stress due to hydrostatic pressure; however, greater amplitude decreases the stress magnitude of point loads directed along the suture. In our models, sutural complexity does not predict greater resistance to hydrostatic pressure but it does seem to increase resistance to point loads, such as would be from predators. This result permits discussion of palaeoecological reconstructions on the basis of septal morphology. We further suggest that the ratio used to characterize septal morphology in the septal strength index and in calculations of tensile strength of nacre are likely insufficient. A better understanding of the material properties of cephalopod nacre may allow the estimation of maximum depth limits of shelled cephalopods through finite element analysis.
Understanding the regulation of vertebrate hematopoiesis and blood disorders – big lessons from a small fish
Authors: Robertson Anne L. , Avagyan Serine , Gansner John M. , Zon Leonard I.
Published: September 2016

Hematopoietic stem cells (HSCs) give rise to all differentiated blood cells. Understanding the mechanisms that regulate self‐renewal and lineage specification of HSCs is key for developing treatments for many human diseases. Zebrafish have emerged as an excellent model for studying vertebrate hematopoiesis. This review will highlight the unique strengths of zebrafish and important findings that have emerged from studies of blood development and disorders using this system. We discuss recent advances in our understanding of hematopoiesis, including the origin of HSCs, molecular control of their development, and key signaling pathways involved in their regulation. We highlight significant findings from zebrafish models of blood disorders and discuss their application for investigating stem cell dysfunction in disease and for the development of new therapeutics.
Crystal structure of the zinc‐bound HhoA protease from Synechocystis sp. PCC 6803
Authors: Dong Wei , Wang Jia , Niu Guoqi , Zhao Shun , Liu Lin
Published: September 2016

The high temperature requirement A (HtrA) proteases are oligomeric serine proteases essential for protein quality control. HtrA homolog A (HhoA) from the photosynthetic cyanobacterium Synechocystis sp. PCC 6803 assembles into a proteolytically active hexamer. Herein, we present the crystal structure of the hexameric HhoA in complex with the copurified peptide. Our data indicate the presence of three methionines in close proximity to the peptide‐binding site of the PDZ domain. Unexpectedly, we observed that a zinc ion is accommodated within the central channel formed by a HhoA trimer. However, neither calcium nor magnesium showed affinity for HhoA. The role of the zinc ion in HhoA was tested in an in vitro proteolytic assay against the nonspecific substrate β‐casein and was found to be inhibitory. Our findings provide insights into the regulation of HhoA by a redox‐related mechanism involving methionine residues and by zinc ion‐binding within the central channel.
Long‐lasting negative ionospheric storm effects in low and middle latitudes during the recovery phase of the 17 March 2013 geomagnetic storm
Authors: Yue Xinan , Wang Wenbin , Lei Jiuhou , Burns Alan , Zhang Yongliang , Wan Weixing , Liu Libo , Hu Lianhuan , Zhao Biqiang , Schreiner William S.
Published: September 2016

In this paper, an ionospheric electron density reanalysis algorithm was used to generate global optimized electron density during the 17–18 March 2013 geomagnetic storm by assimilating ~10 low Earth orbit satellites based and ~450 ground global navigation satellite system receiver‐based total electron content into a background ionospheric model. The reanalyzed electron density could identify the large‐scale ionospheric features quite well during storm time, including the storm‐enhanced density, the positive ionospheric storm effect during the initial and main phases, and the negative ionospheric storm effect during the recovery phase. The simulations from the Thermosphere Ionosphere Electrodynamics General Circulation Model can reproduce similar large‐scale ionospheric disturbances as seen in the reanalysis results. Both the reanalysis and simulations show long‐lasting (>17 h) daytime negative storm effect over the Asia sector as well as hemispheric asymmetry during the recovery phase. Detailed analysis of the Global Ultraviolet Imager‐derived O/N2 ratio and model simulations indicate that the polar ward meridional wind disturbance, the downward E × B drift disturbance and O/N2 depletion might be responsible for the negative storm effect. The hemispheric asymmetry is mainly caused by the geomagnetic field line configuration, which could cause hemispheric asymmetry in the O/N2 depletion.
Nonpolar organic compounds as PM2.5 source tracers: Investigation of their sources and degradation in the Pearl River Delta, China
Authors: Wang Qiongqiong , Feng Yongming , Huang X. H. Hilda , Griffith Stephen M. , Zhang Ting , Zhang Qingyan , Wu Dui , Yu Jian Zhen
Published: September 2016

A group of nonpolar organic compounds (NPOCs) in five compound classes including alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, and 1,3,5‐triphenylbenzene were quantified in samples of particulate matter of aerodynamic diameter less than 2.5 μm collected at four sites in the Pearl River Delta (PRD) region, China, over a 2 year period from 2011 to 2012. The four sites include industrial (Nanhai), urban (Guangzhou), urban outskirt (Dongguan), and suburban (Nansha) locations. Some NPOCs are uniquely emitted from particular combustion sources and thereby serving as markers in source apportionment. Based on this multiyear and multisite NPOC data set, spatial and seasonal variations, correlation analysis, and ratio‐ratio plots were used to investigate the source information and degradation of NPOC tracers. In summer, NPOCs showed distinct local emission characteristics, with urban sites having much higher concentrations than suburban sites. In winter, regional transport was an important influence on NPOC levels, driving up concentrations at all sampling sites and diminishing an urban‐suburban spatial gradient. The lighter NPOCs exhibited more prominent seasonal variations. Such spatiotemporal features suggest that their particle‐phase abundance is more influenced by temperature, which is a critical factor in controlling the extent of semivolatile organics partitioned into the aerosol phase. The heavier NPOCs, especially PAHs, showed negligible correlation among the four sites, suggesting more influence from local emissions. Ratio‐ratio plots indicate photodegradation and mixing of various sources for the NPOCs in the PRD. A positive matrix factorization (PMF) analysis of this large NPOC data set suggests that heavier NPOCs are more suitable source indicators than lighter NPOCs. Incorporating particle‐phase light NPOC concentrations in PMF produces a separate factor, which primarily contains those light NPOCs and likely is not a source factor. Total NPOC concentrations predicted using Pankow partitioning theory were explored as PMF inputs; however, the PMF solution is not able to fully explain the input total concentrations or to give reasonable source profiles, suggesting the need for reliable gas‐phase NPOC data before their use in source apportionment studies. In addition, degradation of NPOCs needs to be considered to avoid misinterpretation of PMF source apportionment results.
Diurnal timescale feedbacks in the tropical cumulus regime
Authors: Ruppert James H.
Published: September 2016

Although the importance of the diurnal cycle in modulating clouds and precipitation has long been recognized, its impact on the climate system at longer timescales has remained elusive. Mounting evidence indicates that the diurnal cycle may substantially affect leading climate modes through nonlinear rectification. In this study, an idealized cloud‐resolving model experiment is executed to isolate a diurnal timescale feedback in the shallow cumulus regime over the tropical warm pool. This feedback is isolated by modifying the period of the diurnal cycle (or removing it), which proportionally scales (or removes) the diurnal thermodynamic forcing that clouds respond to. This diurnal forcing is identified as covarying cycles of static stability and humidity in the lower troposphere, wherein the most unstable conditions coincide with greatest humidity each afternoon. This diurnal forcing yields deeper clouds and greater daily‐mean cumulus heating than would otherwise occur, in turn reducing large‐scale subsidence from day to day according to the “weak temperature gradient” approximation. This diurnal forcing therefore manifests as a timescale feedback by accelerating the onset of deep convection. The longwave cloud‐radiation effect is found to amplify this timescale feedback, since the resulting invigoration of clouds (increased upper‐cloud radiative cooling, with suppressed cooling below) scales with cloud depth (i.e., optical thickness), and hence with the magnitude of diurnal forcing. These findings highlight the pressing need to remedy longstanding problems related to the diurnal cycle in many climate models. Given the evident sensitivity of climate variability to diurnal processes, doing so may yield advances in climate prediction at longer timescales.
Quantifying and reducing leakage errors in the JPL RL05M GRACE mascon solution
Authors: Wiese David N. , Landerer Felix W. , Watkins Michael M.
Published: September 2016

Recent advances in processing data from the Gravity Recovery and Climate Experiment (GRACE) have led to a new generation of gravity solutions constrained within a Bayesian framework to remove correlated errors rather than relying on empirical filters. The JPL RL05M mascon solution is one such solution, solving for mass variations using spherical cap mass concentration elements (mascons), while relying on external information provided by near‐global geophysical models to constrain the solution. This new gravity solution is fundamentally different than the traditional spherical harmonic gravity solution, and as such, requires different care when postprocessing. Here we discuss two classes of postprocessing considerations for the JPL RL05M GRACE mascon solution: (1) reducing leakage errors across land/ocean boundaries, and (2) scaling the solutions to account for leakage errors introduced through parameterizing the gravity solution in terms of mascons. A Coastline Resolution Improvement (CRI) filter is developed to reduce leakage errors across coastlines. Synthetic simulations reveal a reduction in leakage errors of ∼50%, such that residual leakage errors are ∼1 cm equivalent water height (EWH) averaged globally. A set of gain factors is derived to reduce leakage errors for continental hydrology applications. The combined effect of the CRI filter coupled with application of the gain factors, is shown to reduce leakage errors when determining the mass balance of large (>160,000 km2) hydrological basins from 11% to 30% (0.6–1.5 mm EWH) averaged globally, with local improvements up to 38%–81% (9–19 mm EWH).
Near‐Infrared Saturable Absorption of Defective Bulk‐Structured WTe2 for Femtosecond Laser Mode‐Locking
Authors: Koo Joonhoi , Jhon Young In , Park June , Lee Junsu , Jhon Young Min , Lee Ju Han
Published: September 2016

Mono‐ and few‐layer transition metal dichalcogenides (TMDCs) have been widely used as saturable absorbers for ultrashort laser pulse generation, but their preparation is complicated and requires much expertise. The possible use of bulk‐structured TMDCs as saturable absorbers is therefore a very intriguing and technically important issue in laser technology. Here, for the first time, it is demonstrated that defective, bulk‐structured WTe2 microflakes can serve as a base saturable absorption material for fast mode‐lockers that can produce femtosecond pulses from fiber laser cavities. They have a modulation depth of 2.85%, from which stable laser pulses with a duration of 770 fs are readily obtained at a repetition rate of 13.98 MHz and a wavelength of 1556.2 nm, which is comparable to the performance achieved using mono‐ and few‐layer TMDCs. Density functional theory calculations show that the oxidative and defective surfaces of WTe2 microflakes do not degrade their saturable absorption performance in the near‐infrared range, allowing for a broad range of operative bandwidth. This study suggests that saturable absorption is an intrinsic property of TMDCs without relying on their structural dimensionality, providing a new direction for the development of TMDC‐based saturable absorbers.
Enhanced Water‐Splitting Performance of Perovskite SrTaO2N Photoanode Film through Ameliorating Interparticle Charge Transport
Authors: Zhong Yujiao , Li Zhaosheng , Zhao Xin , Fang Tao , Huang Huiting , Qian Qinfeng , Chang Xiaofeng , Wang Peng , Yan Shicheng , Yu Zhentao , Zou Zhigang
Published: September 2016

Here SrTaO2N has been found to exhibit photoelectrochemical water splitting, with a theoretical solar‐to‐hydrogen efficiency of 14.4%. Ameliorating the interparticle charge transport by H2 annealing, the solar photocurrent of the SrTaO2N(H) granular film at 1.23 V versus reversible hydrogen electrode (RHE) is increased by ≈250% in comparison with the SrTaO2N film. Using an aberration corrected scanning transmission electron microscope and super‐X energy dispersive spectroscopy, the atomic scale observation has proved a decrease of oxygen concentrations in the surface of SrTaO2N(H) particle, which may allow its electrical conductivity to be increased from 0.77 × 10−6 to 2.65 × 10−6 S cm−1 and therefore the charge separation efficiency has been greatly increased by ≈330%. After being modified by Co–Pi water oxidation catalyst, the SrTaO2N(H) photoanode shows a solar photocurrent of 1.1 mA cm−2 and an incident photo‐to‐current efficiency value of ≈20% at 400–460 nm and 1.23 V versus RHE, which suggests that it is a new promising photoanode material for solar water splitting.
Colloidal Synthesis and Applications of Plasmonic Metal Nanoparticles
Authors: Yang Peipei , Zheng Jianzhong , Xu Yong , Zhang Qiao , Jiang Lin
Published: September 2016

Plasmonic metal nanoparticles attract intense research attention because of their fascinating surface plasmon resonance properties and their potential applications in diverse fields. Here, some of the recent research efforts on the synthesis and applications of plasmonic metal nanoparticles are highlighted. Starting from the colloidal synthesis of metal nanoparticles, various shaped silver and gold nanostructures are discussed. The applications of plasmonic nanoparticles in photocatalysis, surface‐enhanced Raman spectroscopy (SERS), and devices are used as excellent examples showcasing the advantages of these nanoparticles. The report closes with a brief summary and discussion on the challenges and future direction in this research field.
Influence of Pt Nanoparticle Induced Defects and Surface Coverage in Determining Asymmetric Programming/Erasing Signatures for Nanocrystal Embedded Nonvolatile Memory Applications
Authors: Mukherjee Somik , Zheng Haisheng , Gangopadhyay Keshab , Gangopadhyay Shubhra
Published: September 2016

Metal nanocrystal embedded nonvolatile memory (NVM) devices have attracted significant attention over the past two decades as promising alternatives to conventional floating gate memory devices. This study explores the applicability of sub‐2 nm Pt nanoparticle (NP) embedded in ALD Al2O3 as charge storage nodes in Si‐based NVM devices. The influence of Pt NP‐induced border traps within Al2O3 near the Si surface and their surface coverage dependent pinning of Pt NP work function are explored as part of this study. The pinning of the nanocrystal memories induced by a high density of dangling bonds near the Pt NP/Al2O3 interface skews the expected charging/discharging characteristics with electron programming favored over holes. The degree of this pinning has been probed utilizing C–V measurements and has been dependent on the density of Al2O3 dangling bonds near the Pt NP surface. This density of dangling bonds acting as border traps has been observed as an increasing function of the Pt NP surface percent coverage. Gaining adequate understanding the location, energy, and positioning of the energy levels of these defects at the metal/high‐k interface relative to Si band gap can help overcome poor retention and leakage issues that typically compromise the performance of new generation memory devices.
Combined Biocatalytic and Chemical Transformations of Oleic Acid to ω‐Hydroxynonanoic Acid and α,ω‐Nonanedioic Acid
Authors: Koppireddi Satish , Seo Joo‐Hyun , Jeon Eun‐Yeong , Chowdhury Partha Sarathi , Jang Hyun‐Young , Park Jin‐Byung , Kwon Yong‐Uk
Published: September 2016

A practical chemoenzymatic method for the synthesis of 9‐hydroxynonanoic acid and 1,9‐nonanedioic acid (i.e., azelaic acid) from oleic acid [(9Z)‐octadec‐9‐enoic acid] was investigated. Biotransformation of oleic acid into 9‐(nonanoyloxy)nonanoic acid via 10‐hydroxyoctadecanoic acid and 10‐keto‐octadecanoic acid was driven by a C‐9 double bond hydratase from Stenotrophomonas maltophilia, an alcohol dehydrogenase from Micrococcus luteus, and a Baeyer–Villiger monooxygenase (BVMO) from Pseudomonas putida KT2440, which was expressed in recombinant Escherichia coli. After production of the ester (i.e., the BVMO reaction product), the compound was chemically hydrolyzed to n‐nonanoic acid and 9‐hydroxynonanoic acid because n‐nonanoic acid is toxic to E. coli. The ester was also converted into 9‐hydroxynonanoic acid and the n‐nonanoic acid methyl ester, which can be oxygenated into the 9‐hydroxynonanoic acid methyl ester by the AlkBGT from P. putida GPo1. Finally, 9‐hydroxynonanoic acid was chemically oxidized to azelaic acid with a high yield under fairly mild reaction conditions. For example, whole‐cell biotransformation at a high cell density (i.e., 10 g dry cells/L) allowed the final ester product concentration and volumetric productivity to reach 25 mM and 2.8 mM h−1, respectively. The overall molar yield of azelaic acid from oleic acid was 58%, based on the biotransformation and chemical transformation conversion yields of 84% and 68%, respectively.

magnified image
Rare Metal‐Free Photo‐Aerobic Intramolecular Dehydrogenative Cyclization Reaction towards Polycyclic Heteroarenes
Authors: Yamaguchi Eiji , Sudo Yusuke , Tada Norihiro , Itoh Akichika
Published: September 2016

We have achieved a rare‐metal‐free photo‐aerobic intramolecular dehydrogenative coupling reaction from two C—H bonds of indole with malonate. This catalytic system proceeded at room temperature under visible light irradiation with oxygen in the air as a terminal oxidant, and the cyclization products were obtained in good to excellent yields.

magnified image
Large‐Area Carbon Nanosheets Doped with Phosphorus: A High‐Performance Anode Material for Sodium‐Ion Batteries
Authors: Hou Hongshuai , Shao Lidong , Zhang Yan , Zou Guoqiang , Chen Jun , Ji Xiaobo
Published: September 2016

Large‐area phosphorus‐doped carbon nanosheets (P‐CNSs) are first obtained from carbon dots (CDs) through self‐assembly driving from thermal treatment with Na catalysis. This is the first time to realize the conversion from 0D CDs to 2D nanosheets doped with phosphorus. The sodium storage behavior of phosphorus‐doped carbon material is also investigated for the first time. As anode material for sodium‐ion batteries (SIBs), P‐CNSs exhibit superb performances for electrochemical storage of sodium. When cycled at 0.1 A g−1, the P‐CNSs electrode delivers a high reversible capacity of 328 mAh g−1, even at a high current density of 20 A g−1, a considerable capacity of 108 mAh g−1 can still be maintained. Besides, this material also shows excellent cycling stability, at a current density of 5 A g−1, the reversible capacity can still reach 149 mAh g−1 after 5000 cycles. This work will provide significant value for the development of both carbon materials and SIBs anode materials.
Nance–Horan syndrome—The oral perspective on a rare disease
Authors: Gjørup Hans , Haubek Dorte , Jacobsen Pernille , Ostergaard John R.
Published: September 2016

The present study describes seven patients with Nance–Horan syndrome, all referred to a specialized oral care unit in the Central Denmark Region. A literature search on “Nance Horan Syndrome” resulted in 53 publications among which 29 reported on dental findings. Findings reported in these papers have been systematized to obtain an overview of the reported findings and the terminology on dental morphology. All seven patients included in the present study showed deviations of crown morphology on incisors and/or molars. The only consistent and very clear dental aberration was alterations in the tooth morphology that is screwdriver‐shaped incisors and bud molars being most pronounced in the permanent dentition, but were also present in the primary dentition. In addition, three patients had supernumerary teeth, and three had dental agenesis. In conclusion, a dental examination as a part of the diagnostic process may reveal distinct characteristics of the dental morphology, which could be of diagnostic value and facilitate an early diagnosis. In the description of molar morphology in NHS patients, it is recommended to use the term “bud molar.” The combination of congenital cataract, screwdriwer‐shaped incisors and bud‐shaped molars is a strong clinical indication of Nance–Horan syndrome. © 2016 Wiley Periodicals, Inc.
Application of whole‐exome sequencing to unravel the molecular basis of undiagnosed syndromic congenital neutropenia with intellectual disability
Authors: Gauthier‐Vasserot Alexandra , Thauvin‐Robinet Christel , Bruel Ange‐Line , Duffourd Yannis , St‐Onge Judith , Jouan Thibaud , Rivière Jean‐Baptiste , Heron Delphine , Donadieu Jean , Bellanné‐Chantelot Christine , Briandet Claire , Huet Frédéric , Kuentz Paul , Lehalle Daphné , Duplomb‐Jego Laurence , Gautier Elodie , Maystadt Isabelle , Pinson Lucile , Amram Daniel , El Chehadeh Salima , Melki Judith , Julia Sophia , Faivre Laurence , Thevenon Julien
Published: September 2016

Neutropenia can be qualified as congenital when of neonatal onset or when associated with extra‐hematopoietic manifestations. Overall, 30% of patients with congenital neutropenia (CN) remain without a molecular diagnosis after a multidisciplinary consultation and tedious diagnostic strategy. In the rare situations when neutropenia is identified and associated with intellectual disability (ID), there are few diagnostic hypotheses to test. This retrospective multicenter study reports on a clinically heterogeneous cohort of 10 unrelated patients with CN associated with ID and no molecular diagnosis prior to whole‐exome sequencing (WES). WES provided a diagnostic yield of 40% (4/10). The results suggested that in many cases neutropenia and syndromic manifestations could not be assigned to the same molecular alteration. Three sub‐groups of patients were highlighted: (i) severe, symptomatic chronic neutropenia, detected early in life, and related to a known mutation in the CN spectrum (ELANE); (ii) mild to moderate benign intermittent neutropenia, detected later, and associated with mutations in genes implicated in neurodevelopmental disorders (CHD2, HUWE1); and (iii) moderate to severe intermittent neutropenia as a probably undiagnosed feature of a newly reported syndrome (KAT6A). Unlike KAT6A, which seems to be associated with a syndromic form of CN, the other reported mutations may not explain the entire clinical picture. Although targeted gene sequencing can be discussed for the primary diagnosis of severe CN, we suggest that performing WES for the diagnosis of disorders associating CN with ID will not only provide the etiological diagnosis but will also pave the way towards personalized care and follow‐up. © 2016 Wiley Periodicals, Inc.
Psychiatric disorders among women with the fragile X premutation without children affected by fragile X syndrome
Authors: Gossett Amy , Sansone Stephanie , Schneider Andrea , Johnston Cindy , Hagerman Randi , Tassone Flora , Rivera Susan M. , Seritan Andreea L. , Hessl David
Published: September 2016

Several studies have demonstrated increased rates of anxiety and depressive disorders among female carriers of the fragile X premutation. However, the majority of these studies focused on mothers of children with fragile X syndrome, who experience higher rates of parenting stress that may contribute to the emergence of these disorders. The present study compared psychiatric symptom presentation (utilizing measures of current symptoms and lifetime DSM‐IV Axis I disorders) in 24 female carriers without affected children (mean age = 32.1 years) to 26 non‐carrier women from the community (mean age = 30.5 years). We also examined the association between CGG repeat size (adjusted for X activation ratio) and mRNA, with severity of psychiatric symptoms. Women with the premutation reported significantly elevated symptoms of anxiety, depression, interpersonal sensitivity, obsessive‐compulsiveness, and somatization relative to controls during the past week. Carriers had significantly higher rates of lifetime social phobia (42.3%) compared to controls (12.5%); however, this comparison did not remain significant after multiple comparison adjustment. Rates of other psychiatric disorders were not significantly elevated relative to controls, though it should be noted that lifetime rates among controls were much higher than previously published population estimates. Although the sample is relatively small, the study of this unique cohort suggests the premutation confers risk for mood and anxiety disorders independent of the stress of parenting children with FXS. Screening for psychiatric disorders in women with the premutation, even before they become parents, is important and highly encouraged. © 2016 Wiley Periodicals, Inc.
Correlation between the performance of organic bulk‐heterojunction solar cells and the molecular structures of alcohol solvents
Authors: Liu Zhihai , Seo Soonmin , Lee Eun‐Cheol
Published: September 2016

Morphology control is an important issue for boosting the performance of organic bulk‐heterojunction (BHJ) solar cells. In this study, we investigated the correlation between alcohol solvents and the morphologies of poly({4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′] dithiophene‐2,6‐diyl}{3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl}) (PTB7) and [6,6]‐phenyl‐C70‐butyric acid methyl ester (PC70BM)‐based organic solar cells by spin‐casting the alcohol onto the active layers. We found that the morphologies strongly depended on the structure of the alcohol [alkyl chain length and hydroxyl (OH) group position]. Ethanol or 2‐propanol showed the highest performance among the alcohols considered here. Atomic force microscopy images and absorption spectra demonstrated that the alcohols affected the morphologies of PC70BM rather than those of PTB7. The morphologies of PC70BM were dependent on the solubilities of the alcohols to the active layers and the hydrogen‐bonding strengths between the PC70BM and alcohol molecules. Our results indicate that the use of alcohols for solvent annealing is a simple and efficient method for developing high‐performance organic BHJ solar cells. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44367.
Photo‐crosslinked poly(ethylene glycol) diacrylate (PEGDA) hydrogels from low molecular weight prepolymer: Swelling and permeation studies
Authors: Cavallo Anna , Madaghiele Marta , Masullo Ugo , Lionetto Maria Giulia , Sannino Alessandro
Published: September 2016

The aim of this work was to assess the diffusive properties of poly(ethylene glycol) diacrylate (PEGDA)‐based hydrogels, derived from low MW prepolymers, in view of potential biomedical applications. Several hydrogels were synthesized through UV irradiation of PEGDA solutions for different exposure times. Swelling measurements in distilled water were performed to estimate the yielded crosslink density, while swelling tests at 37 °C in selected media allowed to analyze the mesh size changes induced by various pH and ionic strength (IonS) conditions. The transport of glucose and insulin through thin hydrogel membranes was finally assessed in a modified Ussing chamber at physiological values of pH and IonS (7.4 and 150 mM, respectively). Results showed that the swelling was dependent on the IonS (with swelling reductions up to 20–30% for IonS increases in the range 0–300 mM) and, to a lesser extent, on the pH of the surrounding medium (with swelling increments of about 10% for increasing pH in the range 2.5–11). All hydrogels were also permeable to glucose and insulin, which displayed comparable diffusion coefficients (in the order of 10−6 cm2/s). Specific interactions between glucose and the polymer chains were evidenced by values of the partition coefficient higher than unity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44380.
Preparation of nano‐encapsulated polyethylene wax particles for color toner by in situ emulsion polymerization
Authors: Zang Yao , Ye Mingquan , Han Aijun , Ding Yongyue
Published: September 2016

Polystyrene‐acrylate resin coated polyethylene (PE) wax composite particles used for color toner were prepared by in situ emulsion polymerization. The laser particle analyzer and transmission electron microscope (TEM) were applied to show the size and morphology of composite particles, and thermogravimetric analysis (TGA) was used to characterize the thermal properties of the nanoparticles. With the increase of emulsifier triton x‐100 (TX‐100), the size of composite particles decreased at first and then increased and the shell thickness increased gradually. When the mass ratio of TX‐100 to monomers was 1:10, the core–shell structure of the latex particles was the clearest. The homopolymer of styrene (St) and copolymer of styrene‐butyl acrylate (St‐BA) showed few differences on the size of the composite particles, but a significant difference on the thermal performance. The FTIR spectra and dissolution experiments of PE wax/P(St‐BA) composite particles provided supporting evidence for encapsulation. With the increasing percentage of polyethylene wax, the particles size got larger and emulsion shelf stability became worse. The size and the shelf stability got optimized when the reaction temperature was 80 °C. The average size of the particles initiated by 2,2‐azobisisobutyronitrile (AIBN) was smaller and the size distribution was narrower than those of initiated by potassium persulfate (KPS). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44399.
The side effects of UV light stabilizer on properties of polypropylene based composite tape yarn
Authors: Petrulis Donatas , Petravicius Arturas , Petrulyte Salvinija
Published: September 2016

Initial consuming properties of polypropylene (PP) based composite tape yarns having different portions of ultraviolet (UV) light stabilizer are studied. In many cases, the samples with different portions of UV light stabilizer exhibit changes at level of initial properties, that is, the statistically significant side effects are obtained. When portion of the additive increases, the initial values of width, thickness and linear density of the modified samples are found to be reduced. The additions of UV light stabilizer also generate the statistically significant changes for the most tensile characteristics. The linear and second order polynomial equations are suggested to show the side effects on the properties. Some visual changes in morphology, that is, the differences in smoothness of the surfaces of the samples are also noticed. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44400.
Turn‐On Colorimetric Platform for Dual Activity Detection of Acid and Alkaline Phosphatase in Human Whole Blood
Authors: Hu Qiong , Zhou Baojing , Li Feng , Kong Jinming , Zhang Xueji
Published: September 2016

The activity detection of acid phosphatase (ACP) and alkaline phosphatase (ALP) is of great importance to the diagnosis and prognosis of related diseases. In this work, we report for the first time a turn‐on colorimetric platform for the activity detection of ACP and ALP, by exploiting Cu(BCDS)22− (BCDS=bathocuproinedisulfonate) as the probe. The presence of ACP or ALP dephosphorylates the substrate ascorbic acid 2‐phosphate to produce ascorbic acid, which then reduces Cu(BCDS)22− into Cu(BCDS)23−, leading to a turn‐on spectral absorption at 484 nm and a dramatic color change of the solution from colorless to orange‐red. The underlying metal‐to‐ligand charge‐transfer mechanism has been demonstrated by quantum mechanical computations. This platform allows a rapid, sensitive readout of ACP and ALP activities within the dynamic range from 0 to 220 mU ml−1. In addition, it is highly immune to false‐positive results and also highly selective. More importantly, it is applicable in the presence of human serum and even whole blood samples. These results demonstrate that our platform holds great potential in clinical practices and in the point‐of‐care analysis.
Reactions of Ruthenium Complexes Containing Pentatetraenylidene Ligand
Authors: Tsai Shih‐Hung , Lin Ying‐Chih , Liu Yi‐Hung
Published: September 2016

Two ruthenium acetylide complexes [Ru]−C≡C−C≡C−C(OR)(C3H5)2 (2, R=H and 2 a, R=CH3; [Ru]=Cp(PPh3)2Ru) each with two cyclopropyl rings were synthesized from TMS−C≡C−C≡C−C(OH)(C3H5)2 (1; TMS=trimethylsilyl). Treatments of 2 and 2 a with allyl halide in the presence of KPF6 afforded the vinylidene complexes 3 and 3 a, respectively. When NH4PF6 was used, instead of KPF6, additional ring‐opening reaction took place on one of the three‐membered ring. Treatment of [Ru]Cl with 1,3‐butadiyne (6), bearing an epoxide ring, afforded acetylide complex 7 with a furyl ring. Treatment of 2 a with Ph3CPF6 presumably afforded pentatetraenylidene complex {[Ru]=C=C=C=C=C(C3H5)2}[PF6] (10), which was not isolated. Additions of various alcohols in a solution of 10 generated a number of disubstituted allenylidene complexes {[Ru]=C=C=C(OR)−C=C(C3H5)2}[PF6] (11). Treatment of 11 with K2CO3 afforded the acetylide complex 12 bearing a carbonyl group, characterized by single X‐ray diffraction analysis. Addition of a primary amine to 10 caused cleavage of the farthermost C=C bond and several allenylidene complexes {[Ru]=C=C=C(Me)(NHR)}[PF6] (18) were isolated.
Asymmetric Mannich Reaction of Aryl Methyl Ketones with Cyclic Imines Benzo[e][1,2,3]oxathiazine 2,2‐Dioxides Catalyzed by Cinchona Alkaloid‐based Primary Amines
Authors: Cui Xiao‐Yu , Duan Hui‐Xin , Zhang Yongna , Wang You‐Qing
Published: September 2016

Aryl ketones represent problematic substrates for asymmetric Mannich reactions due to a large steric hindrance exhibited by such compound species. A highly enantioselective direct Mannich reaction of aryl methyl ketones with cyclic imine benzo[e][1,2,3]oxathiazine 2,2‐dioxides could be successfully carried out utilizing a combination of cinchona alkaloid‐derived primary amines with trifluoroacetic acid (TFA); the primary amines feature a superior catalytic efficacy over secondary amines with a variety of sterically hindered carbonyl compounds as substrates. The reaction proceeded well with various cyclic imines in 89–97 % ee and with various aryl methyl ketones in 85–98 % ee. Moreover, the aryl carbonyl of a Mannich product could be transformed to ketoxime, which further undergoes a Beckmann rearrangement to produce an amide compound while maintaining enantioselectivity.
Endo/exo‐synergism of cellulases increases with substrate conversion
Authors: Olsen Johan Pelck , Borch Kim , Westh Peter
Published: September 2016

Synergy between cellulolytic enzymes is important for their industrial utilization, and numerous studies have addressed the problem of how to optimize the composition of enzyme cocktails with respect to this. The degree of synergy (DS) may change with substrate conversion, and some studies have suggested a maximum in DS early in the process. Here, we systematically investigated interrelationships of DS and conversion in a model system covering a wide range of experimental conditions. The results did not reveal any correlation between DS and contact time, but when plotted against the degree of substrate conversion we saw a systematic increase in DS. We suggest that this is linked to a decreasing reactivity of the substrate. Hence, synergy became increasingly important as the recalcitrance of the remaining substrate grew. Such conversion dependent changes in DS appear to be important both in mechanistic studies and attempts to find industrial enzymes blends with optimal synergy. Biotechnol. Bioeng. 2017;114: 696–700. © 2016 Wiley Periodicals, Inc.
Nanoengineered thermoresponsive magnetic hydrogels for biomedical applications
Authors: Jalili Nima A. , Muscarello Madyson , Gaharwar Akhilesh K.
Published: September 2016

“Smart” hydrogels are part of an emerging class of biomaterials that respond to multiple external stimuli. A range of thermoresponsive magnetic hydrogels is currently being developed for on‐demand delivery of biomolecules for a range of biomedical applications, including therapeutic drug delivery, bioimaging, and regenerative engineering. In this review article, we explore different types of magnetic nanoparticles and thermoresponsive polymers used to fabricate these smart nanoengineered hydrogels. We highlight some of the emerging applications of these stimuli‐responsive hydrogels for biomedical applications. Finally, we capture the growing trend of these smart nanoengineered hydrogels and will identify promising new research directions.
Combination of Thiol‐Additive‐Free Native Chemical Ligation/Desulfurization and Intentional Replacement of Alanine with Cysteine
Authors: Tsuda Shugo , Mochizuki Masayoshi , Nishio Hideki , Yoshiya Taku
Published: September 2016

We report a novel strategy for native chemical ligation (NCL). Alanines not located at a ligation site are temporarily replaced with cysteines, and this enables efficient thiol‐additive‐free NCL, with subsequent desulfurization to regenerate the target peptide. We synthesized stresscopin‐related peptide and neuroendocrine regulatory peptide‐2 (NERP‐2) by this method. We confirmed that both conventional alkyl thioester and thioester‐equivalent N‐acyl‐N′‐methyl‐benzimidazolinone (MeNbz) can be adopted as thioester components for thiol‐additive‐free NCL of multi‐Cys‐containing peptides.
Percutaneous transapical pseudoaneurysm closure following transcatheter aortic valve replacement
Authors: Okuyama Kazuaki , Chakravarty Tarun , Makkar Raj R.
Published: September 2016

Left ventricular pseudoaneurysm (LVP) formation is a rare but potentially life‐threatening complication of transapical transcatheter aortic valve replacement (TAVR). Conventionally, a pseudoaneurysm has been treated surgically; however, improved transcatheter technique and device technology have made a percutaneous closure of LVP an increasingly viable option, especially in a patient unfavorable for surgery. A TAVR candidate is most likely at increased surgical‐risk or inoperable. Therefore a percutaneous closure can be a reasonable strategy for LVP, but its experience following this emerging aortic valve procedure remains limited. We describe a case of LVP formation after TAVR in which it was efficiently treated with a percutaneous closure using a transapical approach via LVP. The first attempt was performed with a transfemoral approach. Pre‐closure angiography revealed an eccentric shape of a LVP neck like a “chicken leg”. This shape caused serious difficulty to cross LVP with a wire and it was not accomplished. However, the LVP location was at the apex and we could access from a chest wall through the pseudoaneurysm in the second attempt. This approach allowed a close and coaxial wire manipulation and the neck of LVP was finally crossed. After that, a closure device was deployed and the second procedure was successfully completed. An approach selection often contributes to a procedural success. This is the first case of a percutaneous LVP closure following TAVR using a transapical access and may suggest this approach as a possible option for this catheter closure in TAVR candidates. © 2016 Wiley Periodicals, Inc.
Acute cardiac decompensation in a patient with beta‐thalassemia and diabetes mellitus following cessation of chelation therapy
Authors: Lioudaki Eirini , Whyte Martin
Published: September 2016

Key Clinical Message

Patients with higher liver iron stores are likely to have a worse cardiac outcome following noncompliance with chelation. Cardiovascular magnetic resonance identifies myocardial siderosis allowing optimization of iron chelation regimes. Diabetes puts thalassemic patients at increased risk of myocardial fibrosis. Dual chelation therapy with deferoxamine and deferiprone offers improved cardiac outcomes.
Enhanced Capacitive Desalination Performance of Porous Carbon Spheres@MnO2 Composite
Authors: Chen Bingwei , Wang Yanfang , Yu Feng , Zhu Yusong , Zhang Lixin , Wu Yuping
Published: September 2016

A porous carbon spheres@MnO2 composite is prepared and used as the electrosorption electrode. The MnO2 nanoparticles are evenly distributed on the porous carbon spheres. The as‐prepared composite possesses high specific surface area of 258.6 m2•g−1. Its electrochemical evaluations confirm that the composite has high specific capacitance of 175 F•g−1 at a current density of 1 A•g−1 in 0.5 mol•L−1 NaCl aqueous solution, and shows good conductivity and excellent cycling performance. Electrosorption capacity for the porous carbon spheres@MnO2 composite is 6.28 mg•g−1. Moreover, the composite electrode exhibits excellent recyclability with an efficient regeneration process.
One Step Fabrication of Co3O4‐PPy Cathode for Lithium‐O2 Batteries
Authors: Shao Xuan , Zhang Tao , Wen Zhaoyin
Published: September 2016

Conventional binders in the cathode of Li‐O2 batteries are insulated, and integrate with the catalyst and the conducting carbon‐support by physical mixing. This limits the transfer of electrons, degrades the cathode structure due to swelling, and finally leads to capacity fading and is deleterious to cycleability. In this study, we realized, for the first time, a one‐step fabricated Co3O4‐PPy cathode characterized by an in‐situ formed conductive polymer binder. The functional binder, polypyrrole (PPy), was synthesized through electrical method, which acted as both the binder and supporting material in the Li‐O2 battery. Based on the conductive property of PPy, we obtained the Co3O4‐PPy@Ni electrode via the process of CV electro‐deposition. This method results in uniform distribution of Co3O4 nanoparticles and can simplify the preparation process of the air cathodes. The Li‐O2 battery with the Co3O4‐PPy@Ni cathode can discharge/charge for over 30 cycles under the limited specific capacity of 1000 mAh/g. The cycleability and impedance spectra of the Li‐O2 battery with the functional binder of PPy are superior to the battery with conventional binders.
Spin Self‐Assembled Clay Nanocomposite Passivation Layers Made from a Photocrosslinkable Poly(vinyl alcohol) and Na+‐Montmorillonite Enhance the Environmental Stability of Organic Thin‐Film Transistors
Authors: Jeon Hayoung , Park Seonuk , Nam Sooji , Shin Kwonwoo , Kim Sung‐Ryong , Kim Se Hyun , Jang Jaeyoung , An Tae Kyu
Published: September 2016

We investigated the effects of the multilayer polymer‐clay nanohybrid passivation films on the stability of pentacene organic thin‐film transistors (OTFTs) exposed to air and UV irradiation. Well‐ordered multilayer films were deposited by the spin‐assisted layer‐by‐layer assembly method using photocrosslinkable poly(vinyl alcohol) with the N‐methyl‐4(4′‐formylstyryl)pyridinium methosulfate acetal group (SbQ‐PVA) and Na+‐montmorillonite in a water‐based solution process. When photocrosslinked, these SbQ‐PVA/clay multilayers were found to serve as excellent barriers to O2 and UV‐light. Moreover, when used as passivation layers, they enhanced the stability of pentacene OTFT devices exposed to air and UV radiation.