bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioselective Dihydroxylation of Alkenes Catalyzed by 1,4‐Bis(9‐O‐dihydroquinidinyl)phthalazine‐Modified Binaphthyl–Osmium Nanoparticles
Authors: Zhu Jie , Sun Xiao‐Tao , Wang Xiao‐Dong , Wu Lei 
Published: October 2017

AbstractA series of unprecedented binaphthyl–osmium nanoparticles (OsNPs) with chiral modifiers were applied in the heterogeneous asymmetric dihydroxylation of alkenes. A remarkable size effect of the OsNPs, depending on the density of the covalent organic shells, on the reactivity and enantioselectivity of the dihydroxylation reaction was revealed. Successful recycling of the OsNPs was also demonstrated and high reaction efficiency and enantioselectivity were maintained.
Chiral Ferrocenyl N,N Ligands with Intramolecular Hydrogen Bonds for Highly Enantioselective Allylic Alkylations
Authors: Yao Lin , Nie Huifang , Zhang Dongxu , Wang Libin , Zhang Yuhao , Chen Weiping , Li Zhenhua , Liu Xueying , Zhang Shengyong 
Published: October 2017

AbstractSeveral new ferrocene‐derived bidentate N ligands, which contain multiple chiral factors, have been designed and synthesized by a rational combination of oxazoline and pyridine. Their catalytic performances were investigated preliminarily in Pd‐catalyzed asymmetric allylic alkylation, and excellent reactivities and enantioselectivities (up to 99 % yield and 98 % ee) were realized if we used the ligand with a matched chirality. DFT calculations were used to illustrate that an intramolecular hydrogen bond formed between the hydroxyl group and the oxazoline fragment of the ligand contributed to the optimal conformation of the ligand‐Pd‐allyl complex.
Achieving High 1H Nuclear Hyperpolarization Levels with Long Lifetimes in a Range of Tuberculosis Drug Scaffolds
Authors: Norcott Philip , Rayner Peter J. , Green Gary G. R. , Duckett Simon B. 
Published: October 2017

AbstractDespite the successful use of isoniazid, rifampicin, pyrazinamide and ethambutol in the treatment of tuberculosis (TB), it is a disease of growing global concern. We illustrate here a series of methods that will dramatically improve the magnetic resonance imaging (MRI) detectability of nineteen TB‐relevant agents. We note that the future probing of their uptake and distribution in vivo would be expected to significantly enhance their efficacy in disease treatment. This improvement in detectability is achieved by use of the parahydrogen based SABRE protocol in conjunction with the 2H‐labelling of key sites within their molecular structures and the 2H‐labelling of the magnetization transfer catalyst. The T1 relaxation times and polarization levels of these agents are quantified under test conditions to produce a protocol to identify structurally optimized motifs for future detection. For example, deuteration of the 6‐position of a pyrazinamide analogue leads to a structural form that exhibits T1 values of 144.5 s for 5‐H with up to 20 % polarization. This represents a >7‐fold extension in relaxation time and almost 10‐fold improvement in polarization level when compared to its unoptimized structure.
Synthesis of Mono‐ and Bis(fluoroalkyl)pyrimidines from FARs, Fluorinated Acetoacetates, and Malononitrile Provides Easy Access to Novel High‐Value Pyrimidine Scaffolds
Authors: Schmitt Etienne , Commare Bruno , Panossian Armen , Vors Jean‐Pierre , Pazenok Sergiy , Leroux Frédéric R. 
Published: October 2017

AbstractA new strategy was developed using fluorinated acetoacetates, malononitrile, and fluoroalkyl amino reagents (FARs) to access unprecedented 4,6‐bis(fluoroalkyl)pyrimidine‐5‐carboxylates, their carboxylic acid analogues, and 4‐amino‐6‐(fluoroalkyl)pyrimidine‐5‐carbonitriles. An efficient cyclization step using suitable amidines was developed under microwave irradiation, providing the desired pyrimidines rapidly and efficiently. Standard saponification conditions were applied from carboxylate derivatives to access to the corresponding carboxylic acids. These new valuable building blocks, bearing either a single or two emergent fluorinated substituents, hold strong potential for medicinal and agrochemical research.
Ambireactive (R3P)2BH2 Groups Facilitating Temperature‐Switchable Bond Activation by an Iron Complex
Authors: Vondung Lisa , Sattler Lars E. , Langer Robert 
Published: October 2017

AbstractAn iron pincer complex containing a hemi‐labile (R3P)2BH2 group exhibits temperature‐switchable reactivity patterns: a reversible B−H activation concomitant with a P−B bond cleavage is observed at room temperature. Below 4 °C, intra‐ and intermolecular C−H activation pathways are becoming faster and more dominant. Mechanistic investigations reveal that the lability of the (R3P)2BH2 group in combination with the exothermic formation of σ‐bonded complexes are responsible for the switchable bond activation. Finally, a protocol for an iron‐catalyzed H/D‐exchange of organic solvents in the absence of oxidants has been developed.
Specific optical rotation is a versatile tool for the identification of critical micelle concentration and micellar growth of tartaric acid–based diastereomeric amphiphiles
Authors: Raghavan Vijay , Polavarapu Prasad L. 
Published: October 2017

AbstractFour novel tartaric acid–based diastereomeric chiral amphiphiles, two being enantiomers of the other two, have been synthesized and investigated using chiroptical spectroscopic methods, along with tensiometry and dynamic light scattering experiments. We found that an inflection point in specific optical rotation (SOR) values at ~0.32 mM corresponds to the critical micelle concentration (CMC). The increase in magnitude of SOR values beyond CMC corresponds to the growth of aggregates. For enantiomers, oppositely signed SOR values were observed, ruling out the possibility for the presence of aggregation size mediated artefacts. SOR values did not exhibit concentration dependence for a chiral tartaric acid based non‐aggregating analogue further establishing the absence of artefacts or anomalous interaction of tartaric acid based head group with solvent. Electronic circular dichroism spectra showed no significant changes in band positions or intensities with concentration. Due to the requirement for higher concentrations (~200 mM) needed to obtain vibrational circular dichroism spectra, these measurements are not found to be useful for studying concentration dependent properties of chiral amphiphiles.
Treatment decisions and employment of breast cancer patients: Results of a population‐based survey
Authors: Jagsi Reshma , Abrahamse Paul H. , Lee Kamaria L. , Wallner Lauren P. , Janz Nancy K. , Hamilton Ann S. , Ward Kevin C. , Morrow Monica , Kurian Allison W. , Friese Christopher R. , Hawley Sarah T. , Katz Steven J. 
Published: October 2017

BACKGROUNDMany patients with breast cancer work for pay at the time of their diagnosis, and the treatment plan may threaten their livelihood. Understanding work experiences in a contemporary population‐based sample is necessary to inform initiatives to reduce the burden of cancer care.METHODSWomen who were 20 to 79 years old and had been diagnosed with stage 0 to II breast cancer, as reported to the Georgia and Los Angeles Surveillance, Epidemiology, and End Results registries in 2014‐2015, were surveyed. Of the 3672 eligible women, 2502 responded (68%); 1006 who reported working before their diagnosis were analyzed. Multivariate models evaluated correlates of missing work for >1 month and stopping work altogether versus missing work for ≤1 month.RESULTSIn this diverse sample, most patients (62%) underwent lumpectomy; 16% underwent unilateral mastectomy (8% with reconstruction); and 23% underwent bilateral mastectomy (19% with reconstruction). One‐third (33%) received chemotherapy. Most (84%) worked full‐time before their diagnosis; however, only 50% had paid sick leave, 39% had disability benefits, and 38% had flexible work schedules. Surgical treatment was strongly correlated with missing >1 month of work (odds ratio [OR] for bilateral mastectomy with reconstruction vs lumpectomy, 7.8) and with stopping work altogether (OR for bilateral mastectomy with reconstruction vs lumpectomy, 3.1). Chemotherapy receipt (OR for missing >1 month, 1.3; OR for stopping work altogether, 3.9) and race (OR for missing >1 month for blacks vs whites, 2.0; OR for stopping work altogether for blacks vs whites, 1.7) also correlated. Those with paid sick leave were less likely to stop working (OR, 0.5), as were those with flexible schedules (OR, 0.3).CONCLUSIONSWorking patients who received more aggressive treatments were more likely to experience substantial employment disruptions. Cancer 2017;123:4791‐9. © 2017 American Cancer Society.
Influence of atrial contraction dynamics on cardiac function
Authors: Land  Sander , Niederer Steven Alexander 
Published: October 2017

AbstractIn recent years, there has been a move from monoventricular or biventricular models of the heart, to more complex models that incorporate the electromechanical function in all 4 chambers. However, the biophysical foundation is still underdeveloped, with most work in atrial cellular models having focused on electrophysiological properties. Here, we present a biophysical model of human atrial contraction at body temperature and use it to study the effects of atrial contraction on whole organ function and a study of the effects of remodelling due to atrial fibrillation on atrial and ventricular function.
Nitrogen‐Doped Porous Carbon Nanospheres from Natural Sepia Ink: Easy Preparation and Extraordinary Capacitive Performance
Authors: Hao Xiaodong , Wang Jie , Ding Bing , Chang Zhi , Wang Ya , Dou Hui , Zhang Xiaogang 
Published: October 2017

AbstractHeteroatom‐doped nanostructured porous carbons have attracted intensive attention for electrical‐double layer capacitors (EDLCs) because of their large surface area and surface functionalization. Here we use biowaste sepia ink as a sustainable source to synthesize nitrogen‐doped highly porous carbon nanospheres by a simple molten salt‐based activation strategy. The introduction of molten salt is not only beneficial for repairing the carbon conjugate network, but can also further improve the activation effect of porogen. The as‐obtained carbon nanospheres (MA‐NCS) displayed a large surface area of 1760 m2 g−1, optimized pore architecture, and high nitrogen content (8.6 wt %). With this design, the MA‐NCS as EDLCs electrode exhibited a remarkable specific capacitance of 320 F g−1 at the current density of 0.5 A g−1 and high rate capability in 6 m KOH electrolyte. Furthermore, the assembled EDLCs demonstrated a high specific capacitance of 130 F g−1 at 0.5 A g−1 in an organic electrolyte (1 m TEABF4/AN), obtaining a maximum energy density of 28.2 Wh kg−1 at a power density of 625 W kg−1. This novel biowaste precursor‐synthesis route presents great potential for facile large‐scale production of high‐performance porous carbons for green and long‐term energy storage.
HPCG and HPGMG benchmark tests on multiple program, multiple data (MPMD) mode on Blue Waters—A Cray XE6/XK7 hybrid system
Authors: Kwack JaeHyuk , Bauer Gregory H. 
Published: October 2017

SummaryThe high‐performance conjugate gradients (HPCG) and high‐performance geometric multi‐grid (HPGMG) benchmarks are alternatives to the traditional LINPACK benchmark (HPL) in measuring the performance of modern HPC platforms. We performed HPCG and HPGMG benchmark tests on a Cray XE6/XK7 hybrid supercomputer, Blue Waters at National Center for Supercomputing Applications (NCSA). The benchmarks were tested on CPU‐based and GPU‐enabled nodes separately, and then we analyzed characteristic parameters that affect their performance. Based on our analyses, we performed HPCG and HPGMG runs in multiple program, multiple data (MPMD) mode in Cray Linux Environment in order to measure their hybrid performance on both CPU‐based and GPU‐enabled nodes. We observed and analyzed several performance issues during those tests. Based on lessons learned from this study, we provide recommendations about how to optimize science applications on modern hybrid HPC platforms.
Ransomware prevention technique using key backup
Authors: Lee Kyungroul , Yim Kangbin , Seo Jung Taek 
Published: October 2017

SummaryIn this paper, a key backup technique for the recovery of files encrypted by ransomware is proposed. Ransomware interferes with the victim's system through abnormal behavior such as locking of the victim's system or encryption of the system or files. Ransomware writers demand money from the victims as a condition for the recovery of the encrypted files and systems that have been seized; systems infected by ransomware cannot be repaired without a decryption key, making the employment of detection and recovery methods urgent. This paper proposes a prevention technique for backing up encryption keys in a secure repository which enables the recovery of ransomware‐infected systems and ransomware‐encrypted files. The proposed technique can be used to repair systems infected by ransomware, thereby ensuring safety against such malicious codes.
Light‐Harvesting Organic Nanocrystals Capable of Photon Upconversion
Authors: Li Li , Zeng Yi , Yu Tianjun , Chen Jinping , Yang Guoqiang , Li Yi 
Published: October 2017

AbstractHarvesting and converting low energy photons into higher ones through upconversion have great potential in solar energy conversion. A light‐harvesting nanocrystal assembled from 9,10‐distyrylanthracene and palladium(II) meso‐tetraphenyltetrabenzoporphyrin as the acceptor and the sensitizer, respectively effects red‐to‐green upconversion under incoherent excitation of low power density. An upconversion quantum yield of 0.29±0.02 % is obtained upon excitation with 640 nm laser of 120 mW cm−2. The well‐organized packing of acceptor molecules with aggregation‐induced emission in the nanocrystals dramatically reduces the nonradiative decay of the excited acceptor, benefits the triplet–triplet annihilation (TTA) upconversion and guides the consequent upconverted emission. This work provides a straightforward strategy to develop light‐harvesting nanocrystals based on TTA upconversion, which is attractive for energy conversion and photonic applications.
Sample preparation method for the combined extraction of ethyl glucuronide and drugs of abuse in hair
Authors: Meier Ulf , Briellmann Thomas , Scheurer Eva , Dussy Franz 
Published: October 2017

AbstractOften in hair analysis, a small hair sample is available while the analysis of a multitude of structurally diverse substances with different concentration ranges is demanded. The analysis of the different substances often requires different sample preparation methods, increasing the amount of required hair sample. When segmental hair analysis is necessary, the amount of hair sample needed is further increased. Therefore, the required sample amount for a full analysis can quickly exceed what is available. To combat this problem, a method for the combined hair sample preparation using a single extraction procedure for analysis of ethyl glucuronide with liquid chromatography‐multistage fragmentation mass spectrometry/multiple reaction monitoring (LC–MS3/MRM) and common drugs of abuse with LC–MRM was developed. The combined sample preparation is achieved by separating ethyl glucuronide from the drugs of abuse into separate extracts by fractionation in the solid‐phase extraction step during sample clean‐up. A full validation for all substances for the parameters selectivity, linearity, limit of detection, limit of quantification, accuracy, precision, matrix effects, and recovery was successfully completed. The following drugs of abuse were included in the method: Amphetamine; methamphetamine; 3,4‐methylenedioxy‐N‐methylamphetamine (MDMA); 3,4‐methylenedioxyamphetamine (MDA); 3,4‐methylenedioxy‐N‐ethylamphetamine (MDE); morphine; 6‐monoacetylmorphine; codeine; acetylcodeine; cocaine; benzoylecgonine; norcocaine; cocaethylene; methadone; 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine (EDDP) and methylphenidate. In conclusion, as only 1 sample preparation is needed with 1 aliquot of hair, the presented sample preparation allows an optimal analysis of both ethyl glucuronide and of the drugs of abuse, even when the sample amount is a limiting factor.
Child maltreatment and eating disorders among men and women in adulthood: Results from a nationally representative United States sample
Authors: Afifi Tracie O. , Sareen Jitender , Fortier Janique , Taillieu Tamara , Turner Sarah , Cheung Kristene , Henriksen Christine A. 
Published: October 2017

AbstractObjectiveChild maltreatment is associated with an increased likelihood of having mood disorders, anxiety disorders, post‐traumatic stress disorder, substance use disorders, and personality disorders, but far less is known about eating disorders. The objective of the current study was to examine the associations between child maltreatment, including harsh physical punishment, physical abuse, sexual abuse, emotional abuse, emotional neglect, physical neglect, and exposure to intimate partner violence, and eating disorders in adulthood among men and women.MethodData were from the National Epidemiologic Survey on Alcohol and Related Conditions wave 3 (NESARC‐III) collected in 2012–2013. The sample was nationally representative of the United States adult population (N = 36,309). Lifetime eating disorders (anorexia nervosa [AN], bulimia nervosa [BN], and binge‐eating disorder [BED]) were assessed using diagnostic and statistical manual of mental disorders, fifth edition (DSM‐5) criteria and the alcohol use disorder and associated disabilities interview schedule‐5 (AUDADIS‐5).ResultsThe prevalence of any lifetime eating disorder was 1.7% (0.8% among men and 2.7% among women). All child maltreatment types were associated with AN, BN, and BED with notable differences among men and women. Overall, the types of child maltreatment with the strongest relationships with any eating disorder were sexual abuse and physical neglect among men and sexual abuse and emotional abuse among women.DiscussionClinicians should be mindful that child maltreatment experiences are associated with increased odds of eating disorders including AN, BED, and BN. Such relationships are significant among men and women although notable gender differences in these relationships exist. Abstract word count = 248.
Overstory‐derived surface fuels mediate plant species diversity in frequently burned longleaf pine forests
Authors: Dell Jane E. , Richards Lora A. , O'Brien Joseph J. , Loudermilk E. Louise , Hudak Andrew T. , Pokswinski Scott M. , Bright Benjamin C. , Hiers J. Kevin , Williams Brett W. , Dyer Lee A. 
Published: October 2017

AbstractFrequently burned low‐latitude coniferous forests maintain a high‐diversity understory. Longleaf pine (Pinus palustrisMill.) forests and woodlands have exceptionally high diversity at fine scales and very frequent fire return intervals (1–3 yr). Furthermore, the positive association between high‐frequency, low‐intensity surface fires and high species richness in longleaf pine ecosystems is well documented but poorly understood. Recent studies have demonstrated additional linkages between specific fuel assemblages and fire intensity at small spatial scales. In this study, we build upon both patterns by using long‐term datasets to examine the relationship between fire and specific fuel types, and how the combination of these two elements contributes to ground cover species diversity. We used 11 yr of monitoring data from longleaf pine forests at Eglin Air Force Base, Florida (USA), to parameterize a structural equation model that examines causal relationships between fuels and fire history on ground cover plant diversity. Overstory‐derived fuels, including pine needle litter, pine cones, and other 10 and 100‐h woody fuels, had the greatest positive impact on diversity in relatively open‐canopied, frequently burned reference stands. A second model examined surface fuel components originating from the forest overstory as characterized by airborne light detection and ranging and found that pine needle litter was positively associated with canopy density. Our parameter estimates for causal relationships between easily measured variables and plant diversity will allow for the development of management models at the stand scale while being informed by fuels measured at the plot scale.
Swarms of brown planthopper migrate into the lower Yangtze River Valley under strong western Pacific subtropical highs
Authors: Lu Ming‐Hong , Chen Xiao , Liu Wan‐Cai , Zhu Feng , Lim Ka‐Sing , McInerney Caitríona E. , Hu Gao 
Published: October 2017

AbstractWindborne migration of insects is significantly influenced by meteorological factors and phenomena, such as seasonal atmospheric circulation. Large‐scale movement of air provides the background for all weather and climate events. Hence, population abundances of migratory insects may fluctuate due to variations in seasonal atmospheric circulation, but little is known about this process. The western Pacific subtropical high pressure (WPSH) is the major circulation system that affects weather and climate in eastern Asia. Annual migration of the brown planthopper (BPH, Nilaparvata lugens [Stål]) in East Asia and the WPSH was investigated. Based on almost three decades of data (1977–2003), it was determined that swarms of BPH migrate into the lower Yangtze Valley in July and form an outbreak population under strong WPSH conditions. An intense WPSH enhanced southwesterly airstreams in southern China to provide a high‐speed vehicle promoting BPH long‐distance migration. In addition, increased precipitation in the Yangtze and Huai valleys formed a rain‐belt barrier that forced BPH landing in the lower Yangtze Valley. Results herein demonstrate that the population abundance of a migratory insect fluctuated in response to climatic conditions caused by seasonal atmospheric circulations.
Testing the keystone community concept: effects of landscape, patch removal, and environment on metacommunity structure
Authors: Resetarits Emlyn J. , Cathey Sara E. , Leibold Mathew A. 
Published: October 2017

AbstractAlthough the influence of regional processes on local patches is well studied, the influence of local patches and their spatial arrangement on regional processes is likely to be complex. One interesting idea is the keystone community concept (KCC); this posits that there may be some patches that have a disproportionately large effect on the metacommunity compared to other patches. We experimentally test theKCCby using replicate protist microcosm metacommunities with single‐patch removals. Removing single patches had no effect on average community richness, evenness and biomass of our metacommunities, but did cause metacommunities to be assembled significantly less by local environmental conditions and more by spatial effects related to stochastic factors. Overall our results show that local patch removal can have large regional effects on structural processes, but indicate that more experiments are needed to find evidence of keystone communities.