bluuebunny/crossref_metadata_2025 huggingface dataset:
The challenge of accurately quantifying future megadrought risk in the American Southwest
Authors: Coats Sloan , Mankin Justin S.
Published: August 2016

American Southwest (ASW) megadroughts represent decadal‐scale periods of dry conditions the near‐term risks of which arise from natural low‐frequency hydroclimate variability and anthropogenic forcing. A large single‐climate‐model ensemble indicates that anthropogenic forcing increases near‐term ASW megadrought risk by a factor of 100; however, accurate risk assessment remains a challenge. At the global‐scale we find that anthropogenic forcing may alter the variability driving megadroughts over 55% of land areas, undermining accurate assessments of their risk. For the remaining areas, current ensembles are too small to characterize megadroughts' driving variability. For example, constraining uncertainty in near‐term ASW megadrought risk to 5 percentage points with high confidence requires 287 simulations. Such ensemble sizes are beyond current computational and storage resources, and these limitations suggest that constraining errors in near‐term megadrought risk projections with high confidence—even in places where underlying variability is stationary—is not currently possible.
Nature of turbulence, dissipation, and heating in space plasmas: From Alfvén waves to kinetic Alfvén waves
Authors: Wu D. J. , Feng H. Q. , Li B. , He J. S.
Published: August 2016

The nature of turbulence, dissipation, and heating in plasma media has been an attractive and challenge problem in space physics as well as in basic plasma physics. A wide continuous spectrum of Alfvénic turbulence from large MHD‐scale Alfvén waves (AWs) in the inertial turbulence regime to small kinetic‐scale kinetic AWs (KAWs) in the dissipation turbulence regime is a typical paradigm of plasma turbulence. The incorporation of current remote observations of AWs in the solar atmosphere, in situ satellite measurements of Alfvénic turbulence in the solar wind, and experimental investigations of KAWs on large plasma devices in laboratory provides a chance synthetically to study the physics nature of plasma turbulence, dissipation, and heating. A session entitled “Nature of Turbulence, Dissipation, and Heating in Space Plasmas: From Alfvén Waves to Kinetic Alfvén Waves” was held as a part of the twelfth Asia Oceania Geosciences Society Annual Meeting, which took place in Singapore between 2 and 7 August 2015. This special section is organized based on the session.
Saltier sea surface water conditions recorded by multiple mid‐Holocene corals in the northern South China Sea
Authors: Guo Yangrui , Deng Wenfeng , Chen Xuefei , Wei Gangjian , Yu Kefu , Zhao Jian‐xin
Published: August 2016

The typical features of the mid‐Holocene can be used to better understand present‐day climate conditions and the potential trends of future climate change. The surface conditions, including sea surface temperature (SST) and sea surface salinity (SSS), of the South China Sea (SCS) are largely controlled by the East Asian monsoon system. Surface water conditions reconstructed from coral proxies can be used to study the evolution of the East Asian monsoon during the mid‐Holocene. However, there are some discrepancies among existing coral‐based studies regarding whether the mid‐Holocene sea surface water was much saltier than the present day surface waters. Based on paired Sr/Ca and δ18O of modern and three fossil corals, this paper reconstructs the patterns of seasonal variation in SSS during the mid‐Holocene in the northern SCS. The Δδ18O records (a proxy for SSS) derived from the three fossil corals were all heavier than that from the modern coral, which suggests the presence of more saline surface waters during the mid‐Holocene in the northern SCS. These results are consistent with previous studies based on records reconstructed from coral and foraminifera, as well as from numerical simulations. Reduced rainfall caused by the strengthened Asian Monsoon and/or the northward shift of the intertropical convergence zone during the mid‐Holocene would explain the increased salinity of the surface waters of the northern SCS. The findings presented here clarify the discrepancies among previous studies and confirm the existence of saltier surface waters in the northern SCS during the mid‐Holocene.
Seeking reasons for the differences in size spectra of electrified storms over land and ocean
Authors: Bang Sarah D. , Zipser Edward J.
Published: August 2016

This study expands upon the results of Bang and Zipser (2015), which demonstrated that oceanic precipitation features with lightning tended to be over 10 times larger and more stratiform than those over continents and suggested the hypothesis that some form of external forcing is acting in ways that lead to both larger features and stronger updrafts over tropical oceans. In this work, we evaluate this hypothesis by using reanalysis data to compare large‐scale vertical motion and thermodynamic data for radar precipitation features in archetypal land and ocean regimes in the Congo and Central Pacific. We then expand our study to the entire Tropical Rainfall Measuring Mission (TRMM) domain (35°S to 35°N) over all seasons. Over the ocean, there is a tendency for stronger large‐scale upward motion, linear organization of the convective region, and larger precipitation areas in systems with lightning. By comparison, over land, features with lightning tend to be smaller, in environments of higher instability, with little difference in large‐scale vertical motion. Expanding our analysis to 21 different regions, we highlight those in which seasonal synoptic patterns and water temperature gradients lead to distributions that are exceptions to the findings that ocean storms with lightning tend to be larger and more mature than land storms with lightning. These findings support the hypothesis that most land storms have updrafts sufficiently strong to develop lightning in their early growth stages, while ocean storms require large‐scale ascent and growth into mesoscale convective systems before convective scale updrafts become strong enough to provide the necessary conditions for lightning.
Interface Effect on Efficiency Loss in Organic Light Emitting Diodes with Solution Processed Emitting Layers
Authors: Ho Szuheng , Chen Ying , Liu Shuyi , Peng Cheng , Zhao Dewei , So Franky
Published: August 2016

The performance of multilayered OLEDs with a solution processed emitting layer (EML) is compared to that of counterparts with an evaporated EML and it is found that the interfacial energy changes at the EML and electron transport layer (ETL) interface is a key factor determining the device efficiency. From the results of exciplex photoluminescence emission at the EML/ETL interface and energetic disorder measurements, it is revealed that there is an energy shift in the solution processed EML along with a band tail broadening compared with the device with an evaporated EML, resulting in inefficient hole blocking at the EML/ETL interface and a decrease in device efficiency. Using an ETL with a deep highest occupied molecular orbital (HOMO) level can ameliorate this problem, resulting in a solution processed OLED with a high external quantum efficiency of 29%.
Highly Stretchable Label‐like Random Laser on Universal Substrates
Authors: Liao Yu‐Ming , Lai Ying‐Chih , Perumal Packiyaraj , Liao Wei‐Cheng , Chang Chi‐Yuan , Liao Chi‐Shiun , Lin Shih‐Yao , Chen Yang‐Fang
Published: August 2016

Random lasers have abundant inherent advantages compared to conventional laser, such as flexibility, size, cost, simple design, and mass production. It has been the hot research topic in recent decades. An integrated random laser label with transferability, flexibility, and temperature sensing is created and demonstrated in this work. The highly stretchable label‐type random laser (HSRL) can not only function stably under 100% strain with at least 500 times test but can also be easily transferred on arbitrary substrates irrespective of the material being rigid, flexible, nonplanar, or rough. In addition to features mentioned above, random laser signals can be stimulated and controlled repetitively within human body temperature. This shows great potential that the HSRL can serve as photonics modules for further advanced developments of a variety of applications covering many different fields, such as wearable systems, robotic sensors, and stretchable information communications.
Aerosol analysis of residual and nanoparticle fractions from spray pyrolysis of poorly volatile precursors
Authors: Harra Juha , Kujanpää Sonja , Haapanen Janne , Juuti Paxton , Mäkelä Jyrki M. , Hyvärinen Leo , Honkanen Mari
Published: August 2016

The quality of aerosol‐produced nanopowders can be impaired by micron‐sized particles formed due to non‐uniform process conditions. Methods to evaluate the quality reliably and fast, preferably on‐line, are important at industrial scales. Here, aerosol analysis methods are used to determine the fractions of nanoparticles and micron‐sized residuals from poorly volatile precursors. This is accomplished using aerosol instruments to measure the number and mass size distributions of Liquid Flame Spray‐generated alumina and silver particles produced from metal nitrates dissolved in ethanol and 2‐ethylhexanoic acid (EHA). The addition of EHA had no effect on silver, whereas, 5% EHA concentration was enough to shift the alumina mass from the residuals to nanoparticles. The size‐resolved aerosol analysis proved to be an effective method for determining the product quality. Moreover, the used on‐line techniques alone can be used to evaluate the process output when producing nanopowders, reducing the need for tedious off‐line analyses. © 2016 American Institute of Chemical Engineers AIChE J, 63: 881–892, 2017
A positron emission particle tracking investigation of the scaling law governing free surface flows in tumbling mills
Authors: Govender Indresan , Richter Max C. , Mainza Aubrey N. , De Klerk David N.
Published: August 2016

Positron Emission Particle Tracking (PEPT) measurements are used to track the flow of
glass beads within a rotating drum fitted with (and without) lifter bars and operated in the cascading and cataracting Froude regimes. After converting the Lagrangian trajectories of a representative radio‐labeled glass bead (the tracer) into Eulerian fields under the ergodic assumption, the bed shape and kinematics are extracted for steady, fully developed flow conditions. Notwithstanding the azimuthal wall effects introduced by the lifter bars, we show a linear scaling
of the local flowing layer thickness (h) with local depth‐averaged velocity
and a constant average shear
for direct measurements spanning the entire flowing layer (not just the central region), and high Froude regimes (cascading and cataracting) not previously investigated by scaling analysis in the literature. © 2016 American Institute of Chemical Engineers AIChE J, 63: 903–913, 2017
Tumor screening in Beckwith–Wiedemann syndrome—To screen or not to screen?
Authors: Kalish Jennifer M. , Deardorff Matthew A.
Published: August 2016

Beckwith–Wiedemann syndrome (BWS) is the most common imprinting disorder and consequently, one of the most common cancer predisposition disorders. Over the past 20 years, our understanding of the genetics and epigenetics leading to BWS has evolved and genotype/phenotype correlations have become readily apparent. Clinical management of these patients is focused on omphaloceles, hypoglycemia, macroglossia, hemihypertrophy, and tumor screening. Until recently, the need for tumor screening has been thought to be largely uniform across all genetic and epigenetic causes of BWS. As tumor risk correlates with genetic and epigenetic causes of BWS, several groups have proposed alterations to tumor screening protocols based on the etiology of BWS. However, there are many challenges inherent in adapting screening protocols. Such protocols must accommodate not only the risk based on genetic and epigenetic causes but also the medical cost‐benefit of screening, the psychological impact on families, and the social‐legal implications of missing a treatable tumor. © 2016 Wiley Periodicals, Inc.
A High‐Energy Charge‐Separated State of 1.70 eV from a High‐Potential Donor–Acceptor Dyad: A Catalyst for Energy‐Demanding Photochemical Reactions
Authors: Lim Gary N. , Obondi Christopher O. , D'Souza Francis
Published: August 2016

A high potential donor–acceptor dyad composed of zinc porphyrin bearing three meso‐pentafluorophenyl substituents covalently linked to C60, as a novel dyad capable of generating charge‐separated states of high energy (potential) has been developed. The calculated energy of the charge‐separated state was found to be 1.70 eV, the highest reported for a covalently linked porphyrin–fullerene dyad. Intramolecular photoinduced electron transfer leading to charge‐separated states of appreciable lifetimes in polar and nonpolar solvents has been established from studies involving femto‐ to nanosecond transient absorption techniques. The high energy stored in the form of charge‐separated states along with its persistence of about 50–60 ns makes this dyad a potential electron‐transporting catalyst to carry out energy‐demanding photochemical reactions. This type of high‐energy harvesting dyad is expected to open new research in the areas of artificial photosynthesis especially producing energy (potential) demanding light‐to‐fuel products.
Complete Transmetalation in a Metal–Organic Framework by Metal Ion Metathesis in a Single Crystal for Selective Sensing of Phosphate Ions in Aqueous Media
Authors: Asha K S , Bhattacharjee Rameswar , Mandal Sukhendu
Published: August 2016

A complete transmetalation has been achieved on a barium metal–organic framework (MOF), leading to the isolation of a new Tb‐MOF in a single‐crystal (SC) to single‐crystal (SC) fashion. It leads to the transformation of an anionic framework with cations in the pore to one that is neutral. The mechanistic studies proposed a core–shell metal exchange through dissociation of metal–ligand bonds. This Tb‐MOF exhibits enhanced photoluminescence and acts as a selective sensor for phosphate anion in aqueous medium. Thus, this work not only provides a method to functionalize a MOF that can have potential application in sensing but also elucidates the formation mechanism of the resulting MOF.
Carbocatalysis in Liquid‐Phase Reactions
Authors: Su Dang Sheng , Wen Guodong , Wu Shuchang , Peng Feng , Schlögl Robert
Published: August 2016

There is broad interest in metal‐free catalysis for sustainable chemistry. Carbocatalysis is a “green” option for catalytic transformations in the gas phase as well as in the liquid phase. This is evident by the numerous reports on gas‐phase dehydrogenation and selective oxidation where carbon can be used as a successful alternative to metal oxide systems. Carbocatalysis for liquid‐phase reactions, especially for organic synthesis, is an emerging research discipline and has undergone rapid development in recent years. This Review provides a critical analysis on the state‐of‐the‐art of carbocatalysts for liquid‐phase reactions, with a focus on the underlying mechanisms as well as the advantages and limitations of metal‐free carbocatalysts.
Electrospun poly(hydroxybutyrate)/chitosan blend fibrous scaffolds for cartilage tissue engineering
Authors: Sadeghi Davoud , Karbasi Saeed , Razavi Shahnaz , Mohammadi Sajjad , Shokrgozar Mohammad Ali , Bonakdar Shahin
Published: August 2016

In this study, polyhydroxybutyrate (PHB) was blended with chitosan (CTS), and electrospun in order to produce more hydrophilic fibrous scaffolds with higher mass loss rates for cartilage tissue engineering application. First, the effects of diverse factors on the average and distribution of fiber's diameter of PHB scaffolds were systematically evaluated by experimental design. Then, PHB 9 wt % solutions were blended with various ratios of CTS (5%, 10%, 15%, and 20%) using trifluoroacetic acid as a co‐solvent, and electrospun. The addition of CTS could decrease both water droplet contact angle from ∼74° to ∼67° and tensile strength from, ∼87 MPa to ∼31 MPa. According to the results, the scaffolds containing 15% and 20% CTS were selected as optimized scaffolds for further investigations. Mass loss percentage of these scaffolds was directly proportional to the amount of CTS. Chondrocytes attached well to the surfaces of these scaffolds. The findings suggested that PHB/CTS blend fibrous scaffolds have tremendous potentials for further investigations for the intended application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44171.
Controlling micro‐ and nanofibrillar morphology of polymer blends in low‐speed melt spinning process. Part I. Profiles ofPLA/PVA‐filament parameters along the spinline
Authors: Tran Nguyen Hoai An , Brünig Harald , Heinrich Gert
Published: August 2016

The profiles of PLA/PVA filament parameters (e.g., temperature, velocity, tensile stress, and apparent elongational viscosity) along the spinline in the low‐speed melt spinning process under various spinning conditions were investigated. Owing to the combination of the filament velocity and filament temperature measurements using laser doppler velocimetry (LDV) and infrared thermography, respectively, the fiber formation zone was determined. The length of the fiber formation zone obtained from filament velocity profilesis always shorter than that obtained from the filament temperature profiles(. Obviously, this unexpected phenomenon occurs for low spinning speeds due to the axial heat conduction effect of the filament along the spinline and the nonuniform radial temperature distribution through the cross‐sectional thick filament. Another remarkable finding is related to the Nusselt number which has been found as nearly constant along the spinline in the low‐speed melt spinning process. Thus, mathematical simulations of the filament temperature profiles will be simplified drastically. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2016,133, 44258.
Cyp3a11‐mediated testosterone‐6β‐hydroxylation decreased, while UGT1a9‐mediated propofol O‐glucuronidation increased, in mice with diabetes mellitus
Authors: Shi Rong , Wu Jiasheng , Meng Cong , Ma Bingliang , Wang Tianming , Li Yuanyuan , Ma Yueming
Published: August 2016

The db/db mouse is one of the most popular animal models for type 2 diabetes mellitus, but changes in the activities of important P450s and UGTs are still not completely clear. This study was designed to investigate the alterations of major hepatic cytochrome P450s and UDP‐glucuronyltransferase enzymes in db/db mice. Mouse liver microsomes (MLMs) were obtained from male db/db mice and their wild type littermates. After incubation of the substrates separately with MLMs, the samples were pooled and analysed by high‐throughput liquid chromatography–tandem mass spectrometry system for the simultaneous study of nine phase I metabolic reactions and three glucuronidation conjugation reactions to determine the activity of the metabolic enzymes. Compared with normal controls, the Clint estimate for testosterone‐6β‐hydroxylation was lower (46%) (p < 0.05), while the Vmax and Clint estimates for propofol O‐glucuronidation were 5‐fold higher (p < 0.01) in the liver microsomes from db/db mice. There was no significant difference in phase I metabolic reactions of phenacetin‐O‐deethylation, coumarin‐7‐hydroxylation, bupropion‐hydroxylation, omeprazole‐5‐hydroxylation, dextromethorphan‐O‐demethylation, tolbutamide‐4‐hydroxylation, chlorzoxazone‐6‐hydroxylation and midazolam‐1‐hydroxylation and in glucuronidation reactions of estradiol 3‐O‐glucuronidation, and 3‐azido‐3‐deoxythymidine glucuronidation. The data suggest that, in db/db mice, the activity of Cyp3a11, catalysing testosterone‐6β‐hydroxylation, decreased, while the activity of UGT1a9, catalysing propofol O‐glucuronidation, increased. Copyright © 2016 John Wiley & Sons, Ltd.
In search of a periodic table of the neurons: Axonal‐dendritic circuitry as the organizing principle
Authors: Ascoli Giorgio A. , Wheeler Diek W.
Published: August 2016

No one knows yet how to organize, in a simple yet predictive form, the knowledge concerning the anatomical, biophysical, and molecular properties of neurons that are accumulating in thousands of publications every year. The situation is not dissimilar to the state of Chemistry prior to Mendeleev's tabulation of the elements. We propose that the patterns of presence or absence of axons and dendrites within known anatomical parcels may serve as the key principle to define neuron types. Just as the positions of the elements in the periodic table indicate their potential to combine into molecules, axonal and dendritic distributions provide the blueprint for network connectivity. Furthermore, among the features commonly employed to describe neurons, morphology is considerably robust to experimental conditions. At the same time, this core classification scheme is suitable for aggregating biochemical, physiological, and synaptic information.
The excitation mechanism of btp2Ir(acac) in CBP host
Authors: Xiao‐Bo Zhang , Fu‐Xiang Wei
Published: August 2016

Whether bis(2‐(2′‐benzo[4,5‐α]thienyl)pyridinato‐N,C3′)iridium(acetylacetonate) (btp2Ir(acac)) emission comes from carrier trapping and/or energy transfer, when doped in the 4,4′‐bis(N‐carbazolyl)biphenyl (CBP) host in organic light‐emitting devices, is not clear; therefore, the btp2Ir(acac) emission in CBP hosts was studied. In the red‐doped device, both N,N′‐bis(1‐naphthyl)‐N,N′‐diphenyl‐1.1′‐bipheny1–4‐4′‐diamine (NPB) and (1,1′‐biphenyl‐4′‐oxy)bis(8‐hydroxy‐2‐methylquinolinato)‐aluminum (BAlq) emission appeared, which illustrated that CBP excitons cannot be formed at two emissive layer (EML) interfaces in the device. In the co‐doped devices, NPB and BAlq emissions disappear and 1,4‐bis[2‐(3‐N‐ethylcarbazoryl)vinyl]benzene (BCzVB) emission appears, illustrating the formation of CBP excitons at two EML interfaces in these devices. The reason for this difference was analyzed and it was found that holes in the NPB layer could be made directly into the CBP host in the EML interface of the red‐doped device. In contrast, holes were injected into CBP host via the btp2Ir(acac)/BCzVB dopants in the co‐doped devices, which facilitated hole injection from the NPB layer to the EML, leading to the formation of CBP excitons at two EML interfaces in the co‐doped devices. Therefore, btp2Ir(acac) emission was caused by carrier trapping in the red‐doped device, while, in the co‐doped devices, it resulted from both carrier trapping and energy transfer from the CBP. Furthermore, it was revealed that the carrier trapping mechanism is less efficient than the energy transfer mechanism for btp2Ir(acac) excitation in co‐doped devices. In summary, our results clarified the excitation mechanism of btp2Ir(acac) in the CBP host.
Cohort study of mesenteric panniculitis and its relationship to malignancy
Authors: Buchwald P , Diesing L , Dixon L , Wakeman C , Eglinton T , Dobbs B , Frizelle F
Published: August 2016

Background

Mesenteric panniculitis (MP) is a rare condition that historically has been associated with the presence of malignancy. Paraneoplastic phenomena in general regress with cure and in most cases with treatment of the cancer. This study was undertaken to determine whether MP regressed with cancer treatment and cure.

Methods

This was a retrospective review of a database of all patients with MP confirmed on CT between 2003 and August 2015 at Christchurch Hospital. Patients were categorized as having malignant or non-malignant disease, and follow-up scans were assessed for remission of MP. Patients with malignancy were further categorized as having malignancy cured or not cured.

Results

A total of 308 patients were identified with possible MP; 135 were excluded as radiological appearances were not typical of MP (43 patients) or there was no follow-up CT (92). Of 173 patients (131 men) included, 75 (43·4 per cent) were diagnosed with malignancy. Follow-up imaging showed that 33 patients (19·1 per cent) had remission of MP, whereas 140 (80·9 per cent) had no remission. There was no difference in the rates of MP remission in the malignancy versus no malignancy groups (P = 1·000), or between groups in which malignancy was cured or not cured (P = 0·572). Nor was there any difference in the rates of MP remission in malignancy cured versus no malignancy groups (P = 0·524).

Conclusion

MP does not behave like a paraneoplastic phenomenon. The association with malignancy is most likely an epiphenomenon of the many CT images acquired for staging of cancer.
Retrospective analysis of 30-day mortality for emergency general surgery admissions evaluating the weekend effect
Authors: McCallum I J D , McLean R C , Dixon S , O'Loughlin P
Published: August 2016

Background

The weekend effect describes excess mortality associated with hospital admission on Saturday or Sunday. This study assessed whether a weekend effect exists for patients admitted for emergency general surgery.

Methods

Data for emergency general surgical admissions to National Health Service hospitals in the Northern Deanery in England between 2000 and 2014 were collected, including demographics, co-morbidities, diagnoses, operations undertaken and outcomes. The primary outcome of interest was in-hospital death within 30 days of admission. Cox regression analysis was undertaken with adjustment for co-variables.

Results

There were 12 100 in-hospital deaths within 30 days of admission (3·3 per cent). The overall 30-day mortality rate reduced significantly during the 15-year interval studied, from 5·4 per cent (2000–2004) to 4·0 per cent (2005–2009) and 2·9 per cent during 2010–2014 (P < 0·001). There was no significant mortality difference for patients admitted at the weekend in adjusted Cox models (hazard ratio (HR) 1·00 for Saturday and 0·90 for Sunday, versus Wednesday). There was a significantly higher mortality for operations undertaken at the weekend (HR 1·15 for Saturday and 1·40 for Sunday; P = 0·021 and P < 0·001 respectively). The significantly increased mortality that was evident for emergency surgery at the weekend compared with weekdays in 2000–2004 (HR 1·46 for Saturday and 1·55 for Sunday; both P < 0·001); had reduced by 2010–2014, when the adjusted mortality risk was not significant (HR 1·18 for Saturday and 1·12 for Sunday).

Conclusion

During the past 15 years there has been a weekend effect in patients undergoing emergency general surgery based on day of operation, but not day of admission. Overall mortality for emergency general surgery has improved significantly, and in the past 5 years the increased mortality risk of weekend surgery has reduced.
Method validation and determination of lisdexamfetamine and amphetamine in oral fluid, plasma and urine by LC–MS/MS
Authors: Comiran Eloisa , Barreto Fabiano , Meneghini Leonardo Z. , Carlos Graciela , Fröehlich Pedro E. , Limberger Renata Pereira
Published: August 2016

Lisdexamfetamine (LDX) is a long‐acting prodrug stimulant indicated for the treatment of attention‐deficit/hyperactivity disorder and binge‐eating disorder symptoms. In vivo hydrolysis of LDX amide bond releases the therapeutically active d‐amphetamine (d‐AMPH). Since toxicological tests in biological samples can detect AMPH from the use of some legal medications, efficient methods are needed in order to correctly interpret the results. The aim of this study was to develop and validate an LC–MS/MS method for the simultaneous quantification of LDX and its main biotransformation product AMPH in human oral fluid, plasma and urine. Calibration curve range for both analytes was 1–128 ng/mL in oral fluid and plasma and 4–256 ng/mL in urine, being the lowest concentration the limit of quantification. Accuracy of the determined values of the target analytes for the five control levels ranged from 94.8 to 111.7% for oral fluid, from 91.3 to 100.2% for plasma and from 94.8 to 109.8% for urine. Imprecision for the five control levels did not exceeded 12.8% for oral fluid, 16.2% for plasma and 17.1% for urine. The method developed for the three matrices was validated and was also successfully applied to assess real samples, showing for the first time the detection of LDX in oral fluid.
Detection of Macromolecular Fractions in HCN Polymers Using Electrophoretic and Ultrafiltration Techniques
Authors: Marín‐Yaseli Margarita R. , Cid Cristina , Yagüe Ana I. , Ruiz‐Bermejo Marta
Published: August 2016

Elucidating the origin of life involves synthetic as well as analytical challenges. Herein, for the first time, we describe the use of gel electrophoresis and ultrafiltration to fractionate HCN polymers. Since the first prebiotic synthesis of adenine by Oró, HCN polymers have gained much interest in studies on the origins of life due to the identification of biomonomers and related compounds within them. Here, we demonstrate that macromolecular fractions with electrophoretic mobility can also be detected within HCN polymers. The migration of polymers under the influence of an electric field depends not only on their sizes (one‐dimensional electrophoresis) but also their different isoelectric points (two‐dimensional electrophoresis, 2‐DE). The same behaviour was observed for several macromolecular fractions detected in HCN polymers. Macromolecular fractions with apparent molecular weights as high as 250 kDa were detected by tricine‐SDS gel electrophoresis. Cationic macromolecular fractions with apparent molecular weights as high as 140 kDa were also detected by 2‐DE. The HCN polymers synthesized were fractionated by ultrafiltration. As a result, the molecular weight distributions of the macromolecular fractions detected in the HCN polymers directly depended on the synthetic conditions used to produce these polymers. The implications of these results for prebiotic chemistry will be discussed.
Initial Molecular Recognition Steps of McjA Precursor during Microcin J25 Lasso Peptide Maturation
Authors: Assrir Nadine , Pavelkova Anna , Dazzoni Régine , Ducasse Rémi , Morellet Nelly , Guittet Eric , Rebuffat Sylvie , Zirah Séverine , Li Yanyan , Lescop Ewen
Published: August 2016

Microcin J25 (MccJ25) has emerged as an excellent model to understand the maturation of ribosomal precursor peptides into the entangled lasso fold. MccJ25 biosynthesis relies on the post‐translational modification of the precursor McjA by the ATP‐dependent protease McjB and the lactam synthetase McjC. Here, using NMR spectroscopy, we showed that McjA is an intrinsically disordered protein without detectable conformational preference, which emphasizes the active role of the maturation machinery on the three‐dimensional folding of MccJ25. We further showed that the N‐terminal region of the leader peptide is involved in interaction with both maturation enzymes and identified a predominant interaction of V43–S55 in the core McjA sequence with McjC. Moreover, we demonstrated that residues K23–Q34 in the N‐terminal McjA leader peptide tend to adopt a helical conformation in the presence of membrane mimics, implying a role in directing McjA to the membrane in the vicinity of the lasso synthetase/export machinery. These data provide valuable insights into the initial molecular recognition steps in the MccJ25 maturation process.
In vitro differentiation potential of human haematopoietic CD34+ cells towards pancreatic β‐cells
Authors: Sunitha Manne Mudhu , Srikanth Lokanathan , Santhosh Kumar Pasupuleti , Chandrasekhar Chodimella , Sarma Potukuchi Venkata Gurunadha Krishna
Published: August 2016

Haematopoietic stem cells (HSCs) possess multipotent ability to differentiate into various types of cells on providing appropriate niche. In the present study, the differentiating potential of human HSCs into β‐cells of islets of langerhans was explored. Human HSCs were apheretically isolated from a donor and cultured. Phenotypic characterization of CD34 glycoprotein in the growing monolayer HSCs was confirmed by immunocytochemistry and flow cytometry techniques. HSCs were induced by selection with beta cell differentiating medium (BDM), which consists of epidermal growth factor (EGF), fibroblast growth factor (FGF), transferrin, Triiodo‐l‐Tyronine, nicotinamide and activin A. Distinct morphological changes of differentiated cells were observed on staining with dithizone (DTZ) and expression of PDX1, insulin and synaptophysin was confirmed by immunocytochemistry. Quantitative real‐time polymerase chain reaction (qRT‐PCR) analysis revealed distinct expression of specific β‐cell markers, pancreatic and duodenal homeobox‐1 (PDX1), glucose transporter‐2 (GLUT‐2), synaptophysin (SYP) and insulin (INS) in these differentiated cells compared to HSCs. Further, these cells exhibited elevated expression of INS gene at 10 mM glucose upon inducing with different glucose concentrations. The prominent feature of the obtained β‐cells was the presence of glucose sensors, which was determined by glucokinase activity and high glucokinase activity compared with CD34+ stem cells. These findings illustrate the differentiation of CD34+ HSCs into β‐cells of islets of langerhans.
Impact of analysis interval size on the quality of optical frequency domain imaging assessments of stent implantation for lesions of the superficial femoral artery
Authors: Miki Kojiro , Fujii Kenichi , Kawasaki Daizo , Shibuya Masahiko , Fukunaga Masashi , Imanaka Takahiro , Tamaru Hiroto , Sumiyoshi Akinori , Nishimura Machiko , Horimatsu Tetsuo , Saita Ten , Kobayashi Yuhei , Honda Yasuhiro , Fitzgerald Peter J. , Masuyama Tohru , Ishihara Masaharu
Published: August 2016

Objectives

This study aimed to investigate the influence of analysis interval size on optical frequency domain imaging (OFDI) assessment of stent therapy for lesions of the superficial femoral artery (SFA). Background. No consensus or validating data are available with respect to the methodology of intravascular imaging analysis for the peripheral arteries. Methods. OFDI was performed for 30 SFA lesions, during endovascular therapy and at the 6‐month follow‐up. Initially, lumen and stent borders were traced at 1‐mm axial intervals. Volumes were calculated using a PC‐based software, and the volume index (VI) was defined as the volume divided by the stent length. Two additional OFDI analyses were performed using 2‐mm and 5‐mm intervals, thereby reducing the number of cross‐sectional image frames analyzed. Results. The mean stent length was 89.7 ± 35.2 mm. The mean difference in baseline minimum lumen area (MLA) was 0.4 mm2 between MLA values from the 1‐mm and 2‐mm interval analyses, and 2.2 mm2 between MLA values from the 1‐mm and 5‐mm interval analyses. In volumetric analysis, there were excellent correlations and good agreements for stent, lumen, and neointimal VI measurements obtained on the basis of different analysis intervals. Conclusions. Using large intervals in OFDI analyses of SFA lesions resulted in few differences in measurement variability of volumetric parameters. However, planar analysis for MLA assessment can be susceptible to high variability when large intervals are applied. © 2016 Wiley Periodicals, Inc.
PFO “angioplasty”: The preparation of a very stiff and long tunnel for device closure
Authors: Butera Gianfranco , Piazza Luciane , Heles Mohamed
Published: August 2016

Introduction

Patent foramen ovale (PFO) closure is a widely performed procedure. Understanding the anatomy is mandatory in order to perform the procedure successfully. The degree of overlap between the septum primum and secundum is called the tunnel. In particular, long and stiff tunnels may prevent the correct positioning of devices that have a fixed distance between the right and left atrial discs.

Patients and Methods

We evaluated retrospectively 361 patients with PFO closure between January 2012 and June 2014 in our institution and were treated due to previous history of ischemic stroke. By TEE, the overlap between septum primum and secundum is usually better seen on the bicaval view that is obtained at 75–90° midesophageal views. Tunnel length and PFO opening were measured. Twelve subjects (median age 35 years; range 30–58 years; three females) showed a long (median 22 mm; range 15–32 mm) and rigid tunnel (median opening 2 mm; range 1–4 mm).

Results

Angioplasty of the tunnel was performed by using peripheral angioplasty balloons with a length ranging from 4 to 8 cm and a diameter between 8 and 12 mm. After angioplasty, the tunnel appeared shorter (12 mm; range 8–16 mm) and less rigid (median opening 8 mm; range 7–12 mm). The following devices were implanted: 25 mm Amplatzer PFO occluder in three patients; 25 mm Gore septal occluder in nine subjects. Median fluoroscopy time was 8 min (range 6–10 min). No complications occurred. At a median follow‐up of 12 months (range 2–18 months), no problems occurred and all subjects but one (trivial residual shunting) showed a complete closure.

Conclusions

Angioplasty of a PFO rigid and stiff tunnel is a feasible and safe option. © 2016 Wiley Periodicals, Inc.
Routine invasive versus selective invasive strategies for Non‐ST‐elevation acute coronary syndromes: An Updated meta‐analysis of randomized trials
Authors: Elgendy Islam Y. , Kumbhani Dharam J. , Mahmoud Ahmed N. , Wen Xuerong , Bhatt Deepak L. , Bavry Anthony A.
Published: August 2016

Objectives

To perform an updated systematic review comparing a routine invasive strategy with a selective invasive strategy for patients with non‐ST‐elevation acute coronary syndromes (NSTE‐ACS) in the era of stents and antiplatelet therapy.

Background

Recent meta‐analyses comparing both strategies have shown conflicting results.

Methods

Electronic databases were searched for randomized trials that compared a routine invasive strategy (i.e., routine coronary angiography +/− revascularization) versus a selective invasive strategy (i.e., medical stabilization and coronary angiography +/− revascularization if objective evidence of ischemia or refractory ischemia) in patients with NSTE‐ACS. Summary odds ratios (OR) were primarily constructed using Peto's model.

Results

Twelve trials with 9,650 patients were included. Compared with a selective invasive strategy, a routine invasive strategy was associated with a reduction in the composite of all‐cause mortality or myocardial infarction (MI) [OR: 0.86, 95% confidence interval (CI) 0.77‐0.96] at a mean follow‐up of 39 months, primarily due to a reduction in the risk of MI (OR: 0.78, 95% CI: 0.68‐0.88). The risk of all‐cause mortality was non‐significantly reduced with a routine invasive strategy (OR: 0.88, 95% CI: 0.77‐1.01). The risk of recurrent angina was reduced with a routine invasive strategy (OR: 0.55, 95% CI: 0.49‐0.62), as well as the risk of future revascularization procedures (OR: 0.35, 95% CI: 0.30‐0.39).

Conclusion

In patients with NSTE‐ACS, a routine invasive strategy reduced the risk of ischemic events, including the risk of mortality or MI. Routine invasive therapy reduced the risk of recurrent angina and future revascularization procedures. © 2016 Wiley Periodicals, Inc.
Not that atretic: Use of an atretic femoral vein for transcatheter pulmonary valve implantation
Authors: Ligon R. Allen , Petit Christopher J.
Published: August 2016

We report a case of a child with congenital heart disease who presented with critical right ventricular outflow tract obstruction and a history of bilateral femoral vein occlusion. He underwent successful right ventricular outflow tract intervention, culminating in transcatheter pulmonary valve implantation, after recanalization of a completely obstructed femoral vein. © 2016 Wiley Periodicals, Inc.
Prognostic value of renal function in patients with aortic stenosis treated with transcatheter aortic valve replacement
Authors: Meneguz‐Moreno Rafael A. , Ramos Auristela IO , Siqueira Dimytri , de Castro‐Filho Antonio , Jatene Tannas , Dias Jeronimo Andreia , Le Bihan David , Moreira Adriana , Arrais Magaly , Abizaid Alexandre , Sousa Amanda , Eduardo Sousa J.
Published: August 2016

Objectives

The objectives of the present study were to analyze the variation of renal function after transcatheter aortic valve replacement (TAVR) focused on acute kidney injury (AKI) and its impact on short‐ and mid‐term mortality.

Background

Changes on renal function after TAVR and their impact on clinical outcomes are incompletely understood until now.

Methods

At two tertiary centers 221 consecutive patients were submitted to TAVR. Kidney injury was defined according to VARC‐2 criteria. Patients were classified according to the presence (group 1) or absence (group 2) of AKI. Creatinine values were collected daily until seventh day after procedure, 1 month, 6 months, and then 1 year after TAVR.

Results

At baseline, groups were similar, except for EuroSCORE II (8.66% vs. 7.34%, P = 0.02) and glomerular filtration rate (GFR) (39.59 vs. 48.49 mL/min.1.73 m2, P = 0.002). Overall 30 day‐mortality and 1‐year mortality were 6.3% and 14.0%, respectively. Both 30‐day mortality (23.1% vs. 1.2%, P < 0.001) and 1‐year mortality (44.2% vs. 4.7%, P < 0.001) were higher in group 1. After multivariable‐adjusted models, the only independent predictor for AKI after TAVR was baseline GFR (HR: 1.37, 95% CI: 1.08–1.77, P = 0.01). The independent risk factors for 1‐year mortality were AKI (HR: 15.66, 95% CI: 6.07–44.63, P < 0.001), COPD (HR: 3.14, 95% CI: 1.05–9.40, P = 0.04) and aortic regurgitation grade postprocedure ≥ 2 (P = 0.05) also after multivariate analysis.

Conclusions

In this TAVR cohort, baseline GFR was the only independent predictor of AKI, which negatively impacted on 30‐day and 1‐year mortality. © 2016 Wiley Periodicals, Inc.
Development and validation of a simple risk score to predict 30‐day readmission after percutaneous coronary intervention in a cohort of medicare patients
Authors: Minges Karl E. , Herrin Jeph , Fiorilli Paul N. , Curtis Jeptha P.
Published: August 2016

Objectives

To develop a risk model that can be used to identify PCI patients at higher risk of readmission who may benefit from additional resources at the time of discharge.

Background

A high proportion of patients undergoing PCI are readmitted within 30 days of discharge.

Methods

The sample comprised patients aged ≥65 years who underwent PCI at a CathPCI Registry®‐participating hospital and could be linked with 100% Medicare fee‐for‐service claims between 01/2007 and 12/2009. The sample (n = 388,078) was randomly divided into risk score development (n = 193,899) and validation (n = 194,179) cohorts. We did not count as readmissions those associated with staged revascularization procedures. Multivariable logistic regression models using stepwise selection models were estimated to identify variables independently associated with all‐cause 30‐day readmission.

Results

The mean 30‐day readmission rates for the development (11.36%) and validation (11.35%) cohorts were similar. In total, 19 variables were significantly associated with risk of 30‐day readmission (P < 0.05), and model c‐statistics were similar in the development (0.67) and validation (0.66) cohorts. The simple risk score based on 14 variables identified patients at high and low risk of readmission. Patients with a score of ≥13 (15.4% of sample) had more than an 18.5% risk of readmission, while patients with a score ≤6 (41.9% of sample) had less than an 8% risk of readmission.

Conclusion

Among PCI patients, risk of readmission can be estimated using clinical factors present at the time of the procedure. This risk score may guide clinical decision‐making and resource allocation for PCI patients at the time of hospital discharge. © 2016 Wiley Periodicals, Inc.
Mechanistic Insights into the Oxygen Reduction Reaction on Metal–N–C Electrocatalysts under Fuel Cell Conditions
Authors: Lopes Thiago , Kucernak Anthony , Malko Daniel , Ticianelli Edson A.
Published: August 2016

Three different transition metal‐C‐N catalysts are tested under a range of fuel cell conditions. It is found that common features of the polarisation curve can be explained by a change in electrocatalytic mechanism. Utilising a simple model to quantify the change in mechanisms, iR‐free results of the fuel cell experiments are fit and found to be represented by a common set of parameters. The change in mechanism is assumed to be a switch from four‐electron reduction of oxygen to water to a two‐electron reduction to hydrogen peroxide followed by disproportionation of the hydrogen peroxide to water and oxygen. The data is used to estimate a mass specific exchange current density towards the oxygen reduction reaction (ORR) to water in the range 10−11–10−13 A g−1 depending on the catalyst. For the reduction of oxygen to hydrogen peroxide, the mass specific exchange current density is estimated to be in the range 10−2–10−3 A g−1. Utilising the electrokinetic model, it is shown how the mass transport losses can be extracted from the polarisation curve. For all three catalyst layers studied, these mass transport losses reach about 100 mV at a current density of 1 A cm−2. Finally a discussion of the performance and site density requirements of the non‐precious metal catalysts are provided, and it is estimated that the activity towards the ORR needs to be increased by an order of magnitude, and the site density by two/three orders of magnitude to compete with platinum as an ORR electrocatalyst.
Intracellular Hydrogen Peroxide Detection with Functionalised Nanoelectrodes
Authors: Marquitan Miriam , Clausmeyer Jan , Actis Paolo , Córdoba Ainara López , Korchev Yuri , Mark Melanie D. , Herlitze Stefan , Schuhmann Wolfgang
Published: August 2016

Hydrogen peroxide (H2O2) is one of the most important reactive oxygen species, and it is involved in a number of cellular processes ranging from signal transduction to immune defence and oxidative stress. It is of great interest to intracellularly quantify H2O2 to improve the understanding of its role in disease processes. In this study, we present an amperometric nanosensor for the quantification of H2O2 at the single‐cell level. Deposition of the electrocatalyst Prussian Blue on carbon nanoelectrodes enables selective H2O2 reduction at mild potentials. Owing to their small size and needle‐type shape, these nanoelectrodes can penetrate the membrane of single living cells, causing only minimal perturbation. The nanosensors allow for the monitoring of penetration‐induced oxidative outbursts as well as the uptake of H2O2 from the extracellular environment in single murine macrophages.
Metal Complexes with Azolate‐Functionalized Multidentate Ligands: Tactical Designs and Optoelectronic Applications
Authors: Lu Chin‐Wei , Wang Yang , Chi Yun
Published: August 2016

This review is aimed at updating the recent development on the metal complexes bearing azolate‐containing chelates that have received a growing attention from both the industrial and academic sectors. Particular emphasis is given to the luminescent metal complexes, for which tridentate and multidentate bonding interactions give rise to both higher ligand field strength and better rigidity versus their bidentate counterparts—consequently, this is beneficial to the chemical stability and emission efficiency needed for applications such as organic light‐emitting diodes and bio‐imaging. Their basic designs involve chelates, such as monoanionic 6‐azolyl 2,2′‐bipyridine, dianionic 2,6‐diazolylpyridine, and 2‐azolyl‐6‐phenylpyridine, and the core metal ion spanning from main group elements, such as GaIII and InIII, to the late transition metal ions such as RuII, OsII, IrIII, and PtII and even the lanthanides. Furthermore, the great versatility of these azolate chelates for assembling the robust and emissive metal complexes, provides bright prospect in future optoelectronic investigations.