bluuebunny/crossref_metadata_2025_split huggingface dataset:
X‐ray Crystal Structure of a Metalled Double‐Helix Generated by Infinite and Consecutive C*‐AgI‐C* (C*:N1‐Hexylcytosine) Base Pairs through Argentophilic and Hydrogen Bond Interactions
Authors: Terrón Angel , Moreno‐Vachiano Blas , Bauzá Antonio , García‐Raso Angel , Fiol Juan Jesús , Barceló‐Oliver Miquel , Molins Elies , Frontera Antonio 
Published: December 2016

AbstractThe synthesis of a metalled double‐helix containing exclusively silver‐mediated C*−C* base pairs is reported herein (C*=N1hexylcytosine). Remarkably, it is the first crystal structure containing infinite and consecutive C*‐AgI‐C* base pairs that form a double helix. The AgI ion occupies the center between two C* residues with N(3)−Ag bond lengths of 2.1 Å and short AgI−AgI distances (3.1 Å) suggesting an interesting argentophilic attraction as a stabilization source of the helical disposition. The solid‐state structure is further stabilized by metal‐mediated base‐pairs, hydrogen bonding and π‐stacking interactions. Moreover, the angle N(3)−Ag‐N(3) is almost linear in the [Ag(N1hexylcytosine)2]+ motif and the bases are not coplanar, thus generating a double‐strand helical aggregate in the solid state. The noncovalent and argentophilic interactions have been rationalized based on DFT calculations.
NMR Hyperpolarization Techniques of Gases
Authors: Barskiy Danila A. , Coffey Aaron M. , Nikolaou Panayiotis , Mikhaylov Dmitry M. , Goodson Boyd M. , Branca Rosa T. , Lu George J. , Shapiro Mikhail G. , Telkki Ville‐Veikko , Zhivonitko Vladimir V. , Koptyug Igor V. , Salnikov Oleg G. , Kovtunov Kirill V. , Bukhtiyarov Valerii I. , Rosen Matthew S. , Barlow Michael J. , Safavi Shahideh , Hall Ian P. , Schröder Leif , Chekmenev Eduard Y. 
Published: December 2016

AbstractInvited for the cover of this issue is a group of researchers coordinated by E. Y. Chekmenev from Vanderbilt University. The image depicts hyperpolarized Xe‐129 and parahydrogen gases and their MRI applications. Read the full text of the article at 10.1002/chem.201603884.
Viral oncoprotein antibodies as a marker for recurrence of Merkel cell carcinoma: A prospective validation study
Authors: Paulson Kelly G. , Lewis Christopher W. , Redman Mary W. , Simonson William T. , Lisberg Aaron , Ritter Deborah , Morishima Chihiro , Hutchinson Kathleen , Mudgistratova Lola , Blom Astrid , Iyer Jayasri , Moshiri Ata S. , Tarabadkar Erica S. , Carter Joseph J. , Bhatia Shailender , Kawasumi Masaoki , Galloway Denise A. , Wener Mark H. , Nghiem Paul 
Published: December 2016

BACKGROUNDMerkel cell carcinoma (MCC) is an aggressive skin cancer with a recurrence rate of >40%. Of the 2000 MCC cases per year in the United States, most are caused by the Merkel cell polyomavirus (MCPyV). Antibodies to MCPyV oncoprotein (T‐antigens) have been correlated with MCC tumor burden. The present study assesses the clinical utility of MCPyV‐oncoprotein antibody titers for MCC prognostication and surveillance.METHODSMCPyV‐oncoprotein antibody detection was optimized in a clinical laboratory. A cohort of 219 patients with newly diagnosed MCC were followed prospectively (median follow‐up, 1.9 years). Among the seropositive patients, antibody titer and disease status were serially tracked.RESULTSAntibodies to MCPyV oncoproteins were rare among healthy individuals (1%) but were present in most patients with MCC (114 of 219 patients [52%]; P < .01). Seropositivity at diagnosis independently predicted decreased recurrence risk (hazard ratio, 0.58; P = .04) in multivariate analyses adjusted for age, sex, stage, and immunosuppression. After initial treatment, seropositive patients whose disease did not recur had rapidly falling titers that became negative by a median of 8.4 months. Among seropositive patients who underwent serial evaluation (71 patients; 282 time points), an increasing oncoprotein titer had a positive predictive value of 66% for clinically evident recurrence, whereas a decreasing titer had a negative predictive value of 97%.CONCLUSIONSDetermination of oncoprotein antibody titer assists in the clinical management of patients with newly diagnosed MCC by stratifying them into a higher risk seronegative cohort, in which radiologic imaging may play a more prominent role, and into a lower risk seropositive cohort, in which disease status can be tracked in part by oncoprotein antibody titer. Cancer 2017;123:1464–1474. © 2016 American Cancer Society.
Preoperative characteristics and cytological features of 136 histologically confirmed pancreatic mucinous cystic neoplasms
Authors: Scourtas Aristana , Dudley Jonathan C. , Brugge William R. , Kadayifci Abdurrahman , Mino‐Kenudson Mari , Pitman Martha B. 
Published: December 2016

BACKGROUNDMucinous cystic neoplasms (MCNs) of the pancreas present a management conundrum. The majority are benign but all are resected due to their malignant potential. Recent studies have recommended nonsurgical management. In the current study, the authors analyzed the preoperative imaging, cytology, and cyst fluid characteristics of 136 histologically confirmed MCNs to assess predictors of a high‐risk (HR) cyst for surgical triage.METHODSMCNs resected at the Massachusetts General Hospital between 1990 and 2014 formed the study cohort. Patient demographics, cyst size, and mural nodules (MNs) by endoscopic ultrasound, cytology, and cyst fluid carcinoembryonic antigen and amylase levels were correlated with histological grade. A HR cyst was defined as high‐grade dysplasia or invasive carcinoma on histology. Performance characteristics were assessed for each parameter, with a cyst size ≥3 cm or a MN on imaging and malignant cytology considered to be “true‐positive” results for predicting malignancy.RESULTSOnly 15 of the 136 cysts had HR histology (11%). On average, patients with HR cysts were older than those with low‐risk cysts (55 years vs 49 years, respectively). High‐grade cytology was the most accurate predictor of malignancy (95%) followed by MN and cyst size together (88%) and MN alone (83%). The average carcinoembryonic antigen level (in ng/mL) increased with the grade of dysplasia but the ranges overlapped between low risk and HR cysts.CONCLUSIONSTo the authors' knowledge, the current study is the largest series to date analyzing the cytological features of histologically confirmed MCN. Cytology is insensitive but very specific for detecting a HR MCN and outperformed imaging for the detection of HR MCN. Endoscopic ultrasound‐guided fine‐needle aspiration and cytology should be performed on any clinically suspected MCN that is being considered for conservative management. Cancer Cytopathol 2017;125:169–177. © 2016 American Cancer Society.
The Influence of Morphology and PbI2 on the Intrinsic Trap State Distribution in Perovskite Films Determined by Using Temperature‐Dependent Fluorescence Spectroscopy
Authors: Wang Yi , Wang Hao‐Yi , Yu Man , Fu Li‐Min , Qin Yujun , Zhang Jian‐Ping , Ai Xi‐Cheng 
Published: December 2016

AbstractPerovskite films with different particle sizes and PbI2 contents were prepared by using a controlled single or sequential method. By means of temperature‐dependent fluorescence spectroscopy, the energetic distribution of intrinsic intragap trap states in perovskite was quantitatively determined, and the radiative charge recombinations through the band edge and via trap states were studied. Furthermore, a series of thermodynamic parameters, such as the demarcation energy between radiative and nonradiative recombination regions, detrapping activation energy, and characteristic temperature, were extracted based on which of the possible radiative and nonradiative recombination mechanisms were proposed. In addition, the correlation between the morphology of the perovskite films, the PbI2 content, and the energetic distribution of the trap states was investigated. Finally, we discuss the structure–function relationship of perovskite films prepared by different methods.
Room‐Temperature Atomic Layer Deposition of Al2O3: Impact on Efficiency, Stability and Surface Properties in Perovskite Solar Cells
Authors: Kot Malgorzata , Das Chittaranjan , Wang Zhiping , Henkel Karsten , Rouissi Zied , Wojciechowski Konrad , Snaith Henry J. , Schmeisser Dieter 
Published: December 2016

AbstractIn this work, solar cells with a freshly made CH3NH3PbI3 perovskite film showed a power conversion efficiency (PCE) of 15.4 % whereas the one with 50 days aged perovskite film only 6.1 %. However, when the aged perovskite was covered with a layer of Al2O3 deposited by atomic layer deposition (ALD) at room temperature (RT), the PCE value was clearly enhanced. X‐ray photoelectron spectroscopy study showed that the ALD precursors are chemically active only at the perovskite surface and passivate it. Moreover, the RT‐ALD‐Al2O3‐covered perovskite films showed enhanced ambient air stability.
Iodide‐Photocatalyzed Reduction of Carbon Dioxide to Formic Acid with Thiols and Hydrogen Sulfide
Authors: Berton Mateo , Mello Rossella , González‐Núñez María Elena 
Published: December 2016

AbstractThe photolysis of iodide anions promotes the reaction of carbon dioxide with hydrogen sulfide or thiols to quantitatively yield formic acid and sulfur or disulfides. The reaction proceeds in acetonitrile and aqueous solutions, at atmospheric pressure and room temperature by irradiation using a low‐pressure mercury lamp. This transition‐metal‐free photocatalytic process for CO2 capture coupled with H2S removal may have been relevant as a prebiotic carbon dioxide fixation.
In Situ Raman Spectroscopic Studies on Concentration of Electrolyte Salt in Lithium‐Ion Batteries by Using Ultrafine Multifiber Probes
Authors: Yamanaka Toshiro , Nakagawa Hiroe , Tsubouchi Shigetaka , Domi Yasuhiro , Doi Takayuki , Abe Takeshi , Ogumi Zempachi 
Published: December 2016

AbstractLithium‐ion batteries have attracted considerable attention due to their high power density. The change in concentration of salt in the electrolyte solution in lithium‐ion batteries during operation causes serious degradation of battery performance. Herein, a new method of in situ Raman spectroscopy with ultrafine multifiber probes was developed to simultaneously study the concentrations of ions at several different positions in the electrolyte solution in deep narrow spaces between the electrodes in batteries. The total amount of ions in the electrolyte solution clearly changed during operation due to the low permeability of the solid–electrolyte interphase (SEI) at the anode for Li+ permeation. The permeability, which is a key factor to achieve high battery performance, was improved (enhanced) by adding film‐forming additives to the electrolyte solution to modify the properties of the SEI. The results provide important information for understanding and predicting phenomena occurring in a battery and for designing a superior battery. The present method is useful for analysis in deep narrow spaces in other electrochemical devices, such as capacitors.
Regional variation in streamflow drivers across a continental climatic gradient
Authors: Trancoso Ralph , Phinn Stuart , McVicar Tim R. , Larsen Joshua R. , McAlpine Clive A. 
Published: December 2016

AbstractStreamflow characteristics are driven by specific flow‐generation mechanisms, which are in turn determined by the biophysical properties of catchments. They provide important environmental services for society and ecosystems, regulating water supply and quality, flood mitigation, and the biological diversity of aquatic ecosystems. This study investigates how the drivers of streamflow characteristics vary at the level of regional management (regional [104 km2] and continental scales [107 km2]) in eastern Australia. Three hydrological signatures were used to represent streamflow characteristics: runoff coefficient, baseflow index, and zero flow ratio. Long‐term streamflow data and 24 spatially distributed biophysical properties from 354 catchments in eastern Australia were analysed with random forest and generalized additive beta regression models to determine the dominant drivers of streamflow characteristics. We found that the main drivers of streamflow characteristics cannot be generalized from region to region and that specific biophysical variables govern their spatial variability. However, some important drivers such as the dryness index and the fraction of photosynthetically active radiation from vegetation explain the variability of streamflow characteristics at both regional and continental scales with differing importance. Our findings also suggest that soil properties have a significant effect on streamflow characteristics at regional scales. However, the relative importance of these soil properties varies among regions depending on the streamflow characteristics. This paper demonstrates that the drivers of streamflow characteristics are scale and region dependent, and biogeographically different regions have specific mechanisms governing streamflow. It opens an avenue to better connect the management perspectives of ecology and hydrology.
A microfluidic device for the delivery of enzymes into cells by liposome fusion
Authors: Kuhn Phillip , Eyer Klaus , Dittrich Petra S. 
Published: December 2016

AbstractLiposomes are versatile carriers of drugs or biomolecules and are ideally suited to transport molecules into cells. However, mechanistic studies to understand and improve the fusion of liposomes with cell membranes and endosomes are difficult. Here, we report a method that allows for stable coimmobilization of liposomes and living cells, thereby bringing the membranes into close contact, which is essential for membrane fusion. The small unilamellar liposomes are tethered to the surface by a linker so that no modification of the liposome membrane for cell binding is required. The cells are positioned above the liposomes by posts that are integrated into the microfluidic device, and a pH drop induces the fusion of the cell‐liposome membranes. Both membrane fusion and release of molecules into the cytosol are visualized by fluorescence dequenching assays. Furthermore, we proved the efficient delivery of the enzyme β‐galactosidase into the cells when a fusogenic liposome composition was used. The device could be used for fusion studies but is also a versatile means for cell transfection.
Diagnostic accuracy between readers for identifying electrographic seizures in critically ill adults
Authors: Tu Bin , Young G. Bryan , Kokoszka Agnieszka , Rodriguez‐Ruiz Andres , Varma Jay , Eerikäinen Linda M. , Assassi Nadege , Mayer Stephan A. , Claassen Jan , Särkelä Mika O. K. 
Published: December 2016

SummaryObjectiveElectrographic seizures in critically ill patients are often equivocal. In this study, we sought to determine the diagnostic accuracy of electrographic seizure annotation in adult intensive care units (ICUs) and to identify affecting factors.MethodsTo investigate diagnostic accuracy, interreader agreement (IRA) measures were derived from 5,769 unequivocal and 6,263 equivocal seizure annotations by five experienced electroencephalogram (EEG) readers after reviewing 74 days of EEGs from 50 adult ICU patients. Factors including seizure equivocality (unequivocal vs. equivocal) and laterality (generalized, partial, or bilaterally independent), cyclicity (cyclic vs. noncyclic), persistency (occurrence of status epilepticus), and patient consciousness level (coma vs. noncoma) were further investigated for their influence on IRA measures.ResultsOn average, 70% of seizures marked by a reference reader overlapped, at least in part, with those marked by a test reader (any‐overlap sensitivity, AO‐Sn). Agreed seizure duration between reader pairs (overlap‐integral sensitivity, OI‐Sn) was 62%, while agreed nonseizure duration (overlap‐integral specificity, OI‐Sp) was 99%. A test reader would annotate one additional seizure not overlapping with a reference reader's annotation in every 11.7 h of EEG, that is, the false‐positive rate (FPR) was 0.0854/h. Classifying seizure patterns into unequivocal and equivocal improved specificity and FPR (unequivocal patterns) but compromised sensitivity only for equivocal patterns. Sensitivity of all and unequivocal annotations was higher for patients with status epilepticus. Specificity was higher for partial than for bilaterally independent unequivocal seizure patterns, and lower for cyclic all seizure patterns.SignificanceDiagnosing electrographic seizures in critically ill adults is highly specific and moderately sensitive. Improved criteria for diagnosing electrographic seizures in the ICU are needed.
Damage‐based seismic planar pounding analysis of adjacent symmetric buildings considering inelastic structure–soil–structure interaction
Authors: Ghandil Mehdi , Aldaikh Hesham 
Published: December 2016

SummaryIn cities and urban areas, building structures located at close proximities inevitably interact under dynamic loading by direct pounding and indirectly through the underlying soil. Majority of the previous adjacent building pounding studies that have taken the structure–soil–structure interaction (SSSI) problem into account have used simple lumped mass–spring–dashpot models under plane strain conditions. In this research, the problem of SSSI‐included pounding problem of two adjacent symmetric in plan buildings resting on a soft soil profile excited by uniaxial earthquake loadings is investigated. To this end, a series of SSSI models considering one‐directional nonlinear impact elements between adjacent co‐planar stories and using a method for direct finite element modeling of 3D inelastic underlying soil volume has been developed to accurately study the problem. An advanced inelastic structural behavior parameter, the seismic damage index, has been considered in this study as the key nonlinear structural response of adjacent buildings. Based on the results of SSSI and fixed base case analyses presented herein, two main problems are investigated, namely, the minimum building separation distance for pounding prevention and seismic pounding effects on structural damage in adjacent buildings. The final results show that at least three times, the International Building Code 2009 minimum distance for building separation recommended value is required as a clear distance for adjacent symmetric buildings to prevent the occurrence of seismic pounding. At the International Building Code‐recommended distance, adjacent buildings experienced severe seismic pounding and therefore significant variations in storey shear forces and damage indices. Copyright © 2016 John Wiley & Sons, Ltd.
Spatial seismic modeling of base‐isolated buildings pounding against moat walls: effects of ground motion directionality and mass eccentricity
Authors: Mavronicola Eftychia A. , Polycarpou Panayiotis C. , Komodromos Petros 
Published: December 2016

SummaryStructural impact between adjacent buildings may induce local and, in some extreme cases, severe damage, especially in the case of seismically isolated buildings. This study parametrically investigates in the three‐dimensional domain the effect of pounding on the peak response of base‐isolated buildings, which are simulated as nonlinear three‐dimensional multi‐degree‐of‐freedom systems. Firstly, it is shown that considering unidirectional, instead of bidirectional, excitations may lead to underestimation of the base drift demands. Subsequently, the peak responses of seismically isolated buildings utilizing lead rubber bearings are studied while varying important parameters, such as the incidence angle of seismic excitations, the available seismic clearance, and mass eccentricities, under the action of bidirectional horizontal excitations. A large number of numerical simulations are performed using a specially developed software that implements an efficient approach to model impacts, taking into account arbitrary locations of contact points. It is found that the peak interstory drift ratio is significantly influenced by the directionality of the ground motion. Therefore, the seismic performance of structures should ideally be assessed examining the peak structural response while bidirectional ground motions are imposed at various incident angles. Furthermore, it is also observed that the interstory drift ratios increase while decreasing the available gap size, up to a certain value. Finally, the parametric analyses indicate that the effects of impact are more severe for structures with mass eccentricities, and in which case, the estimation of the critical incidence angle becomes more laborious. Copyright © 2016 John Wiley & Sons, Ltd.
Biochemical response of the Africanized honeybee exposed to fipronil
Authors: Roat Thaisa C. , Carvalho Stephan M. , Palma Mário S. , Malaspina Osmar 
Published: December 2016

Abstract

Bees are recognized worldwide for their social, economic, and environmental value. In recent decades they have been seriously threatened by diseases and high levels of pesticide use. The susceptibility of bees to insecticides makes them an important terrestrial model for assessing environmental quality, and various biomarkers have been developed for such assessments. The present study aimed to evaluate the activity of the enzymes acetylcholinesterase (AChE), carboxylesterase (CaE), and glutathione-S-transferase (GST) in Africanized honeybees exposed to fipronil. The results showed that fipronil at a sublethal dose (0.01 ng/bee) modulates the activity of CaE in all isoforms analyzed (CaE-1, CaE-2, and CaE-3) in both newly emerged and aged bees, and does not affect the activity of AChE or GST. The recovery of the bees after fipronil exposure was also investigated, and these results demonstrated that even the cessation of fipronil ingestion might not lead to complete recovery of individual bees. Even at low doses, fipronil was shown to cause changes in the activity of key enzymes in bees. The possible consequences of these changes are discussed. Environ Toxicol Chem 2017;36:1652–1660. © 2016 SETAC
Identification of sources of metal in the agricultural soils of the Guanzhong Plain, northwest China
Authors: Deng Wenbo , Li Xuxiang , An Zhisheng , Yang Liu , Hou Kang , Zhang Yue 
Published: December 2016

Abstract

A comprehensive survey was conducted to assess the possible sources and distribution of metals in the agricultural soils of the Guanzhong Plain in northwest China. In total, 227 samples of agricultural soil were collected to determine the content of Pb, Cr, Co, V, Ni, Zn, Cu, As, and Mn by X-ray fluorescence spectrometry. The mean concentrations of metals were 26.2 ± 10.8 mg kg­–1, 71.5 ± 16.8 mg kg−1, 12.7 ± 1.81 mg kg−1, 85.1 ± 7.86 mg kg−1, 30.5 ± 6.17 mg kg−1, 71.1 ± 14.1 mg kg−1, 25.2 ± 5.58 mg kg−1, 12.5 ± 1.94 mg kg−1, and 635.4 ± 84.7 mg kg−1 for Pb, Cr, Co, V, Ni, Zn, Cu, As, and Mn, respectively—slightly higher than the regional background values. Multivariate analysis was used to identify the metal sources, and it was found that Ni and Cr in the agricultural soils were mainly derived from lithological materials, and Pb, Zn, and Cu were mainly from traffic emissions; however, Zn and Cu also originated from mineral fertilizers or pesticides. The other metals originated from industrial emissions. The Nemerow index coupled with geographic information system technology was applied to assess the degree and spatial distribution of metal contamination; the soils studied were classified as slightly polluted, and the most contaminated regions were concentrated in the area surrounding Xi'an city, as well as areas in the southeast and north of the Guanzhong Plain. Environ Toxicol Chem 2017;36:1510–1516. © 2016 SETAC