bluuebunny/crossref_metadata_2025_split huggingface dataset:
Base‐Promoted Tandem Cyclization for the Synthesis of Benzonitriles by C−C Bond Construction
Authors: Zhu Cheng‐Zhi , Wei Yin , Shi Min 
Published: December 2017

AbstractA facile synthesis of benzonitriles via a base‐promoted tandem cyclization reaction of α,β‐unsaturated enones having electron‐withdrawing group (EWG) and 2‐acyl‐acrylonitriles was developed. This new synthetic method to access benzonitriles is suitable for a wide range of substrates. A plausible reaction mechanism is proposed on the basis of previous literature and our own investigations.magnified image
Synthesis of 2‐(Trifluoromethyl)‐dibenzopyranones with Rhodium(III)‐catalyzed Formal anti‐Michael Addition as Key Step
Authors: Pan Ling , Dong Jinhuan , Xie Di , Li Yifei , Liu Qun 
Published: December 2017

AbstractA novel rhodium(III)‐catalyzed synthesis of 2‐(trifluoromethyl)‐dibenzopyranones from easily available 4‐(trifluoromethyl)‐p‐quinols and N‐methoxyarylamides is described. Rhodium(III)‐catalyzed formal anti‐Michael addition was proposed to be a crucial step in this [3+3] annulation with N‐methoxyarylamides as effective 1,3‐dipoles, providing a concise and efficient approach for the construction of trifluoromethyl‐containing dibenzopyranones under mild reaction conditions.magnified image
Tertiary‐Alcohol‐Directed Functionalization of Remote C(sp3)−H Bonds by Sequential Hydrogen Atom and Heteroaryl Migrations
Authors: Wu Xinxin , Wang Mingyang , Huan Leitao , Wang Dongping , Wang Jinwei , Zhu Chen 
Published: December 2017

AbstractReported for the first time is a tertiary‐alcohol‐guided heteroarylation of remote C(sp3)−H bonds. The mild and direct generation of alkoxyl radicals from alcohols is enabled by visible‐light photocatalysis. A remote hydrogen atom and heteroaryl migration sequence are involved in the reaction. Many sensitive groups remain intact in the reaction, thus illustrating wide functional‐group compatibility. This protocol provides a practical strategy for the late‐stage modification of alkyl ketones.
Engineering Multifunctional RNAi Nanomedicine To Concurrently Target Cancer Hallmarks for Combinatorial Therapy
Authors: Liu Yanlan , Ji Xiaoyuan , Tong Winnie W. L. , Askhatova Diana , Yang Tingyuan , Cheng Hongwei , Wang Yuzhuo , Shi Jinjun 
Published: December 2017

AbstractCancer hallmarks allow the complexity and heterogeneity of tumor biology to be better understood, leading to the discovery of various promising targets for cancer therapy. An amorphous iron oxide nanoparticle (NP)‐based RNAi strategy is developed to co‐target two cancer hallmarks. The NP technology can modulate the glycolysis pathway by silencing MCT4 to induce tumor cell acidosis, and concurrently exacerbate oxidative stress in tumor cells via the Fenton‐like reaction. This strategy has the following features for systemic siRNA delivery: 1) siRNA encapsulation within NPs for improving systemic stability; 2) effective endosomal escape through osmotic pressure and/or endosomal membrane oxidation; 3) small size for enhancing tumor tissue penetration; and 4) triple functions (RNAi, Fenton‐like reaction, and MRI) for combinatorial therapy and in vivo tracking.
Stereoselective Construction of Halogenated Quaternary Carbon Centers by Brønsted Base Catalyzed [4+2] Cycloaddition of α‐Haloaldehydes
Authors: Li Qiang , Zhou Liang , Shen Xu‐Dong , Yang Kai‐Chuan , Zhang Xiang , Dai Qing‐Song , Leng Hai‐Jun , Li Qing‐Zhu , Li Jun‐Long 
Published: December 2017

AbstractAsymmetric construction of halogenated quaternary carbon centers under mild reaction conditions remains challenging. Reported here is an unprecedented and highly stereoselective Brønsted base catalyzed [4+2] cycloaddition between either α‐chloro‐ or α‐bromoaldehydes and cyclic enones. The key intermediate, an α‐halogenated enolate, is susceptible to dehalogenation and can be stabilized and stereochemically controlled using bifunctional tertiary amines. This method provides facile access to a collection of optically pure bicyclic dihydropyrans having three contiguous stereocenters, including a halogen‐bearing quaternary carbon center. Of note, the product can be transformed in situ into densely functionalized spirocyclopropanes in a highly efficient and stereoselective manner.
Tandem Molecular Self‐Assembly in Liver Cancer Cells
Authors: Zhan Jie , Cai Yanbin , He Shuangshuang , Wang Ling , Yang Zhimou 
Published: December 2017

AbstractWe herein describe the tandem molecular self‐assembly of a peptide derivative (1) that is controlled by a combination of enzymatic and chemical reactions. In phosphate‐buffered saline (PBS), compound 1 self‐assembles first into nanoparticles by phosphatase and then into nanofibers by glutathione. Liver cancer cells exhibit higher concentrations of both phosphatase and GSH than normal cells. Therefore, the tandem self‐assembly of 1 also occurs in the liver cancer cell lines HepG2 and QGY7703; compound 1 first forms nanoparticles around the cells and then forms nanofibers inside the cells. Owing to this self‐assembly mechanism, compound 1 exhibits large ratios for cellular uptake and inhibition of cell viability between liver cancer cells and normal liver cells. We envision that using both extracellular and intracellular reactions to trigger tandem molecular self‐assembly could lead to the development of supramolecular nanomaterials with improved performance in cancer diagnostics and therapy.
Metalation Control of Open‐Shell Character in meso‐meso Linked Porphyrin meso‐Oxy Radical Dimers
Authors: Jun‐i Yuta , Fukui Norihito , Furukawa Ko , Osuka Atsuhiro 
Published: December 2017

AbstractControl of open‐shell character of meso‐meso linked porphyrin meso‐oxy radical dimers has been demonstrated by core metalation. Namely, NiII‐porphyrin dimer 6Ni exhibits a clear 1H NMR spectrum and a distorted but rather coplanar quinonoidal structure consisting of two ruffled porphyrin rings, in accordance with the previous report. Freebase dimer 6H2 shows a similar quinonoidal structure in the solid state but displays slightly broader and temperature‐dependent 1H NMR spectra, indicating a partial diradical character in solution that increases at high temperature. In sharp contrast, bis‐imidazole‐coordinated ZnII‐porphyrin dimer 6ZnIm2 exhibits a perpendicular structure consisting of two planar ZnII‐porphyrins and has been characterized as a distinct open‐shell diradical on the basis of its non‐observable 1H NMR signals, a clear ESR signal, and a characteristic absorption spectrum reaching about 1700 nm. Despite the distinct diradical character, 6ZnIm2 is an extremely stable molecule.
Mechanistic Insights into Hydrogen Activation by Frustrated N/Sn Lewis Pairs
Authors: Das Shubhajit , Mondal Sukanta , Pati Swapan K. 
Published: December 2017

AbstractThe mechanism of H2 activation by recently reported N/Sn Lewis pairs is unravelled using the representative iPr3SnOTf/DABCO combination. Computations provide evidence for weak intermolecular associations between Lewis acid and Lewis base (LA/LB) in which the counteranion to cationic LA fragment plays a critical role. Two frustrated Lewis pairs (FLPs) are observed; an unprecedented counteranion‐mediated noncovalent LA/LB association is characterised along with the usual FLP structure. Both the FLPs are shown to be capable of H2 activation through cooperative electron transfer processes involving the LA/LB centres. Overall, computed results are in good agreement with the experimental findings and account for the observed reactivity. Insights obtained in this study are fundamentally important for the rational design of Sn‐based alternative FLP LAs. The present findings could also provide a general mechanistic framework for H2 activation by FLPs having an ion pair LA component.
Nanographene Aerogels: Size Effect of the Precursor Graphene Oxide on Gelation Process and Electrochemical Properties
Authors: Kudo Akira , Campbell Patrick G. , Biener Juergen 
Published: December 2017

AbstractImproving the electrochemical properties of graphene aerogels (GAs) without doping or making composites is an attractive synthetic strategy. In this work we report some effects of graphene sheet dimensions on the properties of GAs. Nanographene aerogels (nG‐AGs) were synthesized using nanographene oxide (nGO) powder with a mean platelet diameter of 90 nm. In‐situ Fourier tranformation infrared (FTIR) spectroscopy during gelation revealed a longer fast‐gelation regime for nG‐AGs than for standard graphene aerogels (stdG‐AGs). The surface‐area‐normalized capacitance of nG‐AGs calculated from cyclic voltammetry is 16% higher than that of stdG‐AGs, and the onset of hydrogen evolution is observed at a lower over‐potential. These observations can be attributed to an increased density of edge sites and defects in nanographene sheets. Our results indicate that the diameter of the precursor graphene sheets can be used as a parameter to optimize the electrochemical properties of GAs depending on the application.
Low Circulating Levels of Neurotensin in Women with Nonalcoholic Fatty Liver Disease Associated with Severe Obesity
Authors: Auguet Teresa , Aragonès Gemma , Berlanga Alba , Martínez Salomé , Sabench Fàtima , Aguilar Carmen , Villar Beatriz , Sirvent Joan Josep , Del Castillo Daniel , Richart Cristóbal 
Published: December 2017

ObjectiveThis study was performed to investigate neurotensin plasma levels in patients with nonalcoholic fatty liver disease (NAFLD) associated with severe obesity.MethodsThe plasma levels of neurotensin in 20 women with normal weight and 51 women with morbid obesity (MO) were measured, and women were subclassified according to their hepatic histology as having MO without NAFLD (n = 18) or MO with NAFLD (n = 33). The NAFLD group included 15 women with simple steatosis (SS) and 18 women with nonalcoholic steatohepatitis (NASH). To quantify neurotensin in plasma, a multiplex sandwich immunoassay with a Luminex magnetic bead–based platform was used.ResultsNeurotensin levels were significantly decreased (P = 0.001) in women with MO and NAFLD (3.62 ± 0.85 ng/mL), compared with women with MO and normal liver function (11.65 ± 1.95 ng/mL; P = 0.001) and women with normal weight (13.68 ± 2.58 ng/mL; P = 0.001). There was no difference in levels between women with SS and women with NASH (P = 0.415).ConclusionsCirculating levels of neurotensin were decreased in women with NAFLD associated with MO.
High-resolution IR absorption spectroscopy of polycyclic aromatic hydrocarbons in the 3 μm region: role of hydrogenation and alkylation
Authors: Maltseva Elena , Mackie Cameron J. , Candian Alessandra , Petrignani Annemieke , Huang Xinchuan , Lee Timothy J. , Tielens Alexander G. G. M. , Oomens Jos , Buma Wybren Jan 
Published: December 2017

Aim. We aim to elucidate the spectral changes in the 3 μm region that result from chemical changes in the molecular periphery of polycyclic aromatic hydrocarbons (PAHs) with extra hydrogens (H-PAHs) and methyl groups (Me-PAHs).
Methods. Advanced laser spectroscopic techniques combined with mass spectrometry were applied on supersonically cooled 1,2,3,4-tetrahydronaphthalene, 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, 1,2,3,6,7,8-hexahydropyrene, 9-methylanthracene, and 9,10-dimethylanthracene, allowing us to record mass-selective and conformationally selective absorption spectra of the aromatic, aliphatic, and alkyl CH-stretches in the 3.175 − 3.636 µm region with laser-limited resolution. We compared the experimental absorption spectra with standard harmonic calculations and with second-order vibrational perturbation theory anharmonic calculations that use the SPECTRO program for treating resonances.
Results. We show that anharmonicity plays an important if not dominant role, affecting not only aromatic, but also aliphatic and alkyl CH-stretch vibrations. The experimental high-resolution data lead to the conclusion that the variation in Me- and H-PAHs composition might well account for the observed variations in the 3 μm emission spectra of carbon-rich and star-forming regions. Our laboratory studies also suggest that heavily hydrogenated PAHs form a significant fraction of the carriers of IR emission in regions in which an anomalously strong 3 μm plateau is observed.
Delayed Metallic Embolization of a Cor-Knot Fastener
Authors: Garrett H. 
Published: December 2017

Background The Cor-Knot device is a titanium fastener which is widely used in cardiac valve procedures. Adverse events associated with use of the device have been rare.
Case Description A patient underwent robotic mitral valve repair using the Cor-Knot fastener. Five years later, he suffered a cerebral vascular accident secondary to embolization of a metallic foreign body. He had had no other medical procedures which could account for a source of metallic embolization.
Conclusion Long-term surveillance after use of the Cor-Knot fastener is limited. Metallic embolization may be possible with this device and warrants awareness within the medical community.
Overutilization of Cross-Sectional Imaging in the Lower Extremity Trauma Setting
Authors: Protack Clinton , Wengerter Brian , Jean Raymond , Liu Shirley , Mojibian Hamid , Sumpio Bauer , Dardik Alan , Maung Adrian , Erben Young 
Published: December 2017

Objective In an era of managed care and cost savings, we are faced with the question of whether another test is necessary to confirm our clinical suspicion. We hypothesized that a few computed tomography angiographies (CTAs) are necessary to identify lower extremity vascular injuries (LEVIs). We reviewed our trauma center's experience in the management of LEVI.
Methods A retrospective review of all trauma patients between 2012 and 2016 was performed. Four-thousand nine-hundred fourteen trauma patients were evaluated with 46 suspected LEVIs (either with cross-sectional imaging and/or operative exploration). Our primary end point was the utility of CTA in the setting of LEVI. Receiver operating characteristic curves were performed to evaluate sensitivity and specificity for hard signs and CTA identification of LEVI.
Results Out of the initial 46 patients with suspected LEVI, 41 (89%) had a CTA as part of their initial evaluation. Sixteen patients (35%) with LEVI were due to penetrating injuries. Seventeen patients (41%) had a CTA with LEVI. Fourteen of the 17 patients (82%) with injury on CTA also had hard signs of LEVI. Twenty-two patients (48%) underwent operative exploration: three had no LEVI that was previously believed to be on CTA; operative exploration identified two missed injuries not observed on CTA. Seven of forty-one (17%) CTA studies provided a false assumption of the presence/absence of LEVI. One patient (2%) underwent operative exploration and was found to have LEVI in the absence of hard signs, but with a CTA identifying LEVI.
Conclusion The recognition of hard signs through physical examination is paramount to assessing need for operative intervention with suspicion of LEVI. CTA should be reserved as an adjunct for identification of LEVI in patients with high clinical suspicion and absence of hard signs, rather than utilizing CTA as an initial screening tool for the identification of LEVI.
Social Relations and Technology: Continuity, Context, and Change
Authors: Antonucci Toni C , Ajrouch Kristine J , Manalel Jasmine A 
Published: December 2017

Abstract
Social relations, although basic to human nature, health and well-being, have become increasingly complicated as a result of changing population demography and technology. In this essay, we provide a historical overview of social relations, especially as they affect older people. We briefly review the evolution of theory and measurement surrounding social relations as well as early empirical evidence. We consider how social relations have changed over time as well as continuity and change regarding basic characteristics of social relations. Of special interest is the emerging influence of technology on how people maintain contact, especially the changing ways people can use technology to increase, decrease, maintain, or avoid social relations. We consider both negative and positive aspects of these new technologies and their influence on health and well-being. Finally, we conclude that new and emerging technologies hold great promise for the future by overcoming traditional barriers to maintaining social contact, support exchange, and information acquisition. Nevertheless, we caution that these new technologies can have the dehumanizing effect of distance thus creating the potential for insensitivity and increased negativity. In sum, we are cautiously optimistic about the promise of technology to expand, but not replace, traditional forms of social contact.
Coadapted genomes and selection on hybrids: Fisher’s geometric model explains a variety of empirical patterns
Authors: Simon Alexis , Bierne Nicolas , Welch John J. 
Published: December 2017

AbstractNatural selection plays a variety of roles in hybridization, speciation and admixture. Most research has focused on two extreme cases: crosses between closely-related inbred lines, where hybrids are fitter than their parents, or crosses between effectively isolated species, where hybrids suffer severe breakdown. Many natural populations must fall into intermediate regimes, with multiple types of gene interaction, but these are more difficult to study. Here, we develop a simple fitness landscape model, and show that it naturally interpolates between previous modeling approaches, involving mildly deleterious recessives, or discrete hybrid incompatibilities. The model yields several new predictions, which we test with genomic data fromMytilusmussels, and published data from plants (Zea, PopulusandSenecio) and animals (Mus, TeleogryllusandDrosophila). The predictions are generally supported, and the model explains surprising empirical patterns that have been observed in both extreme regimes. Our approach enables novel and complementary uses of genome-wide datasets, which do not depend on identifying outlier loci, or “speciation genes” with anomalous effects. Given its simplicity and flexibility, and its predictive successes with a wide range of data, the approach should be readily extendable to other outstanding questions in the study of hybridization.
Upper Limit for Angular Compounding Speckle Reduction
Authors: Winetraub Yonatan , Wu Chris , Chu Steven , de la Zerda Adam 
Published: December 2017

AbstractPrevious studies of angular compounding for speckle reduction in optical coherence tomography may not have fully accounted for optical aberrations, which produce unintended spatial averaging and concomitant loss of spatial resolution. We accounted for such aberrations by aligning our system and measuring distortions in the images, and found that speckle reduction by angular compounding was limited. Our theoretical analysis using Monte Carlo simulations indicates that “pure” angular compounding over 13° (our full numerical aperture) can improve the signal-to-noise ratio by no more than a factor of 1.5, significantly lower than values reported in literature. Analysis suggests that illuminating only part of the lens to further reduce speckle also involves a trade-off with resolution roughly equivalent to spatial averaging. We conclude that angular compounding provides substantially less benefit than previously expected.
A complex performance landscape for suction-feeding reveals constraints and adaptations in a population of reef damselfish
Authors: Keren Tal , Kiflawi Moshe , Martin Christopher H , China Victor , Mann Ofri , Holzman Roi 
Published: December 2017

AbstractThe ability to predict how multiple traits interact in determining performance is key to understanding the evolution of complex functional systems. Similar to Simpson’s adaptive landscape, which describes the fitness consequences of varying morphological traits, performance landscapes depict the performance consequences of varying morphological traits. Mapping the population’s location with respect to the topographic features of the landscape could inform us on the selective forces operating on the traits that underlie performance. Here, we used a mechanistic model derived from first principles of hydrodynamics to construct a hypothetical performance landscape for zooplankton prey capture using suction feeding. We then used the landscape to test whether a population of Chromis viridis, a coral reef zooplanktivore, is located on a performance peak or ridge based on measurements of kinematic variables recorded in-situ during undisturbed foraging. Observed trait combinations in the wild population closely matched regions of high feeding performance in the landscape, however the population was not located on a local performance peak. This sub-optimal performance was not due to constraints stemming from the observed trait correlations. The predominant directions of variation of the phenotypic traits was tangent to the ‘path of steepest ascent’ that points towards the local peak, indicating that the population does not reside on a “performance ridge”. Rather, our analysis suggests that feeding performance is constrained by stabilizing selection, possibly reflecting a balance between selection on feeding performance and mechanical or genetic constraints.
Mechanisms of repetitive retrograde contractions in response to sustained esophageal distension: a study evaluating patients with postfundoplication dysphagia
Authors: Carlson Dustin A. , Kahrilas Peter J. , Ritter Katherine , Lin Zhiyue , Pandolfino John E. 
Published: December 2017

Repetitive retrograde contractions (RRCs) in response to sustained esophageal distension are a distinct contractility pattern observed with functional luminal imaging probe (FLIP) panometry that are common in type III (spastic) achalasia. RRCs are hypothesized to be indicative of either impaired inhibitory innervation or esophageal outflow obstruction. We aimed to apply FLIP panometry to patients with postfundoplication dysphagia (a model of esophageal obstruction) to explore mechanisms behind RRCs. Adult patients with dysphagia after Nissen fundoplication ( n = 32) or type III achalasia ( n = 25) were evaluated with high-resolution manometry (HRM) and upper endoscopy with FLIP. HRM studies were assessed for outflow obstruction and spastic features: premature contractility, hypercontractility, and impaired deglutitive inhibition during multiple-rapid swallows. FLIP studies were analyzed to determine the esophagogastric junction (EGJ)-distensibility index and contractility pattern, including RRCs. Barium esophagram was evaluated when available. RRCs were present in 8/32 (25%) fundoplication and 19/25 (76%) achalasia patients ( P < 0.001). EGJ outflow obstruction was detected in 21 (67%) fundoplication patients by HRM, FLIP, or esophagram [6 (29%) had RRCs]. On HRM, none of the fundoplication patients had premature contractility, whereas 3/4 with defective inhibition on multiple-rapid swallows and 2/4 with hypercontractility had RRCs. Regression analysis demonstrated HRM with spastic features, but not esophageal outflow obstruction, as a predictor for RRCs. RRCs in response to sustained esophageal distension appear to be a manifestation of spastic esophageal motility. Although future study to further clarify the significance of RRCs is needed, RRCs on FLIP panometry should prompt evaluation for a major motor disorder. NEW & NOTEWORTHY Repetitive retrograde contractions (RRCs) are a common response to sustained esophageal distension among spastic achalasia patients when evaluated with the functional luminal imaging probe. We evaluated patients with postfundoplication dysphagia, i.e., patients with suspected mechanical obstruction, and found that RRCs occasionally occurred among postfundoplication patients, but often in association with manometric features of esophageal neuromuscular imbalance. Thus, RRCs appear to be a manifestation of spastic esophageal dysmotility, likely from neural imbalance resulting in excess excitation.