bluuebunny/crossref_metadata_2025 huggingface dataset:
Mining opinions from instructor evaluation reviews: A deep learning approach
Authors: Onan Aytuğ
Published: November 2019

Student evaluations of teaching (SET) provides potentially essential source of information to achieve educational quality objectives of higher educational institutions. The findings can be utilized as a measure of teaching effectiveness and they may aid the administrative decision‐making process. The purpose of our research is to establish an efficient sentiment classification scheme on instructor evaluation reviews by pursuing the paradigm of deep learning. Deep learning is a recent research direction of machine learning, which seeks to identify a classification scheme with higher predictive performance based on multiple layers of nonlinear information processing. In this study, we present a recurrent neural network (RNN) based model for opinion mining on instructor evaluation reviews. We analyze a corpus containing 154,000 such reviews, with the use of conventional machine learning algorithms, ensemble learning methods, and deep learning architectures. In the empirical analysis, three conventional text representation schemes (namely, term‐presence, term‐frequency [TF], and TF‐inverse document frequency schemes) and four word embedding schemes (namely, word2vec, global vector [GloVe], fastText, and LDA2Vec) have been taken into consideration. The predictive performance of supervised machine learning methods (such as, Naïve Bayes, support vector machines, logistic regression, K‐nearest neighbor, and random forest) and three ensemble learning methods have been examined on word embedding schemes. The extensive empirical analysis indicates that deep learning‐based architectures outperform the conventional machine learning classifiers for the task of sentiment classification on instructor reviews. For the RNN with attention mechanism in conjunction with GloVe word embedding scheme‐based representation a classification accuracy of 98.29% has been obtained.
Long non‐coding small nucleolar RNA host genes in digestive cancers
Authors: Yang Huan , Jiang Zheng , Wang Shuang , Zhao Yongbing , Song Xiaomei , Xiao Yufeng , Yang Shiming
Published: November 2019

Although long noncoding RNAs (lncRNAs) do not have protein coding capacities, they are involved in the pathogenesis of many types of cancers, including hepatocellular carcinoma, cervical cancer, and gastric cancer. Notably, the roles of lncRNAs are vital in nearly every aspect of tumor biology. Long non‐coding small nucleolar RNA host genes (lnc‐SNHGs) are abnormally expressed in multiple cancers, including urologic neoplasms, respiratory tumors, and digestive cancers, and play vital roles in these cancers. These host genes could participate in tumorigenesis by regulating proliferation, migration, invasion and apoptosis of tumor cells. This review focuses on the overview of the roles that lnc‐SNHGs play in the formation and progression of digestive cancers.
How prisoners and their partners experience the maintenance of their relationship during a prison sentence
Authors: De Claire Karen , Dixon Louise , Larkin Michael
Published: November 2019

Research shows that intimate relationships, and their maintenance via prison visits, have a positive impact on factors associated with prisoner well‐being and reduced likelihood of recidivism. It is therefore in the interest of corrections, government, and wider society to enable prisoners to maintain healthy relationships with their family and intimate partners throughout their prison sentence. Despite this evidence, little is known about how prisoners experience the maintenance of a significant intimate relationship in prison. This study aims to explore heterosexual couples' experiences in maintaining their well‐established intimate relationships, while the male partner is incarcerated. Four main themes were identified: how they experienced “having a special connection” that they were motivated to maintain; “coping with challenges and threats” to that connection; “developing reciprocal behaviours” to meet those challenges; and “maintaining a belief in the future.” Implications for how the relational context of rehabilitation can best be supported is considered.
The color–flavor incongruency effect in product evaluation and brand perception
Authors: Huang Jianping , Wan Xiaoang
Published: November 2019

Crossmodal correspondences refer to the tendency to associate a pair of features across different senses; specifically, consumers can associate the color of packaging with a certain flavor label for packaged foods after repeated exposure to the packaging of mainstream, everyday products. We conducted two studies to examine how the incongruency between packaging color and flavor labeling influences consumers' evaluations of a food product and their perceptions of a brand. The results revealed that the participants liked a food product less when its packaging color was incongruent with its flavor label, but the magnitude of this color–flavor incongruency effect decreased after participants repeatedly searched for these products on the shelves of a virtual supermarket. Participants also considered the brand of packaged foods to be more innovative when the products' packaging colors were incongruent with flavor labels, and the magnitude of this color–flavor incongruency effect on brand perception was not influenced by their experience of searching for a product in virtual reality. Together, these results suggested that crossmodal congruency is an important factor to consider in packaging design and can be used as a marketing tool to increase product likability and attract consumers' attention.
Asymmetric Reduction of (R)‐Carvone through a Thermostable and Organic‐Solvent‐Tolerant Ene‐Reductase
Authors: Tischler Dirk , Gädke Eric , Eggerichs Daniel , Gomez Baraibar Alvaro , Mügge Carolin , Scholtissek Anika , Paul Caroline E.
Published: November 2019

Ene‐reductases allow regio‐ and stereoselective reduction of activated C=C double bonds at the expense of nicotinamide adenine dinucleotide cofactors [NAD(P)H]. Biological NAD(P)H can be replaced by synthetic mimics to facilitate enzyme screening and process optimization. The ene‐reductase FOYE‐1, originating from an acidophilic iron oxidizer, has been described as a promising candidate and is now being explored for applied biocatalysis. Biological and synthetic nicotinamide cofactors were evaluated to fuel FOYE‐1 to produce valuable compounds. A maximum activity of (319.7±3.2) U mg−1 with NADPH or of (206.7±3.4) U mg−1 with 1‐benzyl‐1,4‐dihydronicotinamide (BNAH) for the reduction of N‐methylmaleimide was observed at 30 °C. Notably, BNAH was found to be a promising reductant but exhibits poor solubility in water. Different organic solvents were therefore assayed: FOYE‐1 showed excellent performance in most systems with up to 20 vol% solvent and at temperatures up to 40 °C. Purification and application strategies were evaluated on a small scale to optimize the process. Finally, a 200 mL biotransformation of 750 mg (R)‐carvone afforded 495 mg of (2R,5R)‐dihydrocarvone (>95 % ee), demonstrating the simplicity of handling and application of FOYE‐1.
Structure and Activity of the Thermophilic Tryptophan‐6 Halogenase BorH
Authors: Lingkon Kazi , Bellizzi John J.
Published: November 2019

Flavin‐dependent halogenases carry out regioselective aryl halide synthesis in aqueous solution at ambient temperature and neutral pH using benign halide salts, making them attractive catalysts for green chemistry. BorH and BorF, two proteins encoded by the biosynthetic gene cluster for the chlorinated bisindole alkaloid borregomycin A, are the halogenase and flavin reductase subunits of a tryptophan‐6‐halogenase. Quantitative conversion ofl‐tryptophan (Trp) to 6‐chlorotryptophan could be achieved using 1.2 mol % BorH and 2 mol % BorF. The optimal reaction temperature for Trp chlorination is 45 °C, and the melting temperatures of BorH and BorF are 48 and 50 °C respectively, which are higher than the thermal parameters for most other halogenases previously studied. Steady‐state kinetic analysis of Trp chlorination by BorH determined parameters ofkcat=4.42 min−1, andKMof 9.78 μmat 45 °C. BorH exhibits a broad substrate scope, chlorinating and brominating a variety of aromatic substrates with and without indole groups. Chlorination of Trp at a 100 mg scale with 52 % crude yield, using 0.2 mol % BorH indicates that industrial scale biotransformations using BorH/BorF are feasible. The X‐ray crystal structure of BorH with bound Trp provides additional evidence for the model that regioselectivity is determined by substrate positioning in the active site, showing C6 of Trp juxtaposed with the catalytic Lys79 in the same binding pose previously observed in the structure of Thal.
Improvement in left ventricular function following higher‐risk percutaneous coronary intervention in patients with ischemic cardiomyopathy
Authors: Russo Juan J. , Prasad Megha , Doshi Darshan , Karmpaliotis Dimitrios , Parikh Manish A. , Ali Ziad A. , Popma Jeffrey J. , Pershad Ashish , Ohman E. Magnus , Douglas Pamela S. , O'Neill William W. , Leon Martin B. , Moses Jeffrey W. , Kirtane Ajay J.
Published: November 2019

Background

Surgical revascularization is associated with improved ventricular function and clinical outcomes among patients with ischemic cardiomyopathy. There are less extensive data on changes in ventricular function among patients with ischemic cardiomyopathy undergoing percutaneous coronary intervention (PCI). Accordingly, we sought to assess the extent and predictors of change in left ventricular ejection fraction (ΔLVEF) among patients undergoing hemodynamically‐supported PCI.

Methods

We assessed ΔLVEF following hemodynamically‐supported PCI (with Impella or intra‐aortic balloon counterpulsation) among patients enrolled in the PROTECT II trial and cVAD registry. The ΔLVEF was compared among patients with paired echocardiography at baseline and at least 30 days of follow‐up. Independent correlates of ΔLVEF (modeled continuously and with an absolute ΔLVEF≥5%) were assessed using multivariable models.

Results

Among the 689 patients with paired echocardiographic data included in the analysis, the mean LVEF improved from 24.8 ± 9.9% to 31.4 ± 13.3% after PCI, for a net increase of 6.5 ± 10.8% (p < .001). A total of 395 (57%) patients had ΔLVEF ≥ 5% following hemodynamically‐supported PCI. The number of vessels treated was associated with ΔLVEF (ΔLVEF 5.5% with 1 vessel, 6.6% with 2 vessels, and 8.3% with 3 vessels, p for trend = .046). A lower baseline LVEF, absence of a history of congestive heart failure or aldosterone receptor antagonist use, and a greater number of vessels treated were independent correlates of LVEF improvement.

Conclusions

Among patients with severe left ventricular systolic dysfunction and paired echocardiographic assessments, an improvement in LVEF was observed following hemodynamically‐supported PCI.
New Role of Pd Hydride as a Sensor of Surface Pd Distributions in Pd−Au Catalysts
Authors: Guan Erjia , Foucher Alexandre C. , Marcella Nicholas , Shirman Tanya , Luneau Mathilde , Head Ashley R. , Verbart David M. A. , Aizenberg Joanna , Friend Cynthia M. , Stacchiola Dario , Stach Eric A. , Frenkel Anatoly I.
Published: November 2019

Isolated or contiguous, the surface distributions of Pd atoms in the Pd−Au bimetallic nanoparticle (NP) catalysts often influence activity and selectivity towards specific reactions. In this study, we used a concomitant Pd hydride formation upon H2 exposure as a probe of presence of contiguous Pd regions in bimetallic NPs. For demonstrating this method, we prepared silica supported monometallic Pd and bimetallic Pd−Au NPs with a Pd/Au ratio of 25/75 (Pd25Au75) and used X‐ray absorption spectroscopy, scanning transmission electron microscopy and infrared spectroscopy to detect and quantitatively analyze the Pd hydride regions. This work provides a new approach to characterizing intra‐particle heterogeneities within the bimetallic NPs at ambient temperature and pressure.
Carbon Layer Coated Ni3S2/MoS2 Nanohybrids as Efficient Bifunctional Electrocatalysts for Overall Water Splitting
Authors: Wang Chao‐Peng , Kong Ling‐Jun , Sun Hao , Zhong Ming , Cui Hui‐Juan , Zhang Ying‐Hui , Wang Dan‐Hong , Zhu Jian , Bu Xian‐He
Published: November 2019

Developing active, stable, and cost‐effective water splitting catalysts is a critical step towards a sustainable energy future. Heterostructures of transition metal chalcogenides have emerged as important candidates for catalyzing oxygen evolution reaction (OER) or hydrogen evolution reaction (HER), due to the synergistic effects originating from the increased active sites or accelerated electron transfer. Current limitation to this strategy lies in the complication of synthesis often resorting to the direct growth of hybrid structures on a conductive current collector. Here, a simple approach is selected to synthesize graphitic carbon layer coated Ni3S2/MoS2 heterostructures (denoted as NMC) with a facile scaffold‐free solvothermal method followed by controlled pyrolysis. The NMC obtained at 600 °C behave as durable, efficient oxygen and hydrogen evolution electrodes with overpotentials of 350 mV and 233 mV respectively at 10 mA cm−2 in 1.0 M KOH. In addition, the catalysts demonstrate a high efficiency for overall water splitting. Such architected catalyst designs may shed light on the development of more efficient bifunctional electrocatalysts.
ZnO‐Templated Selenized and Phosphorized Cobalt‐Nickel Oxide Microcubes as Rapid Alkaline Water Oxidation Electrocatalysts
Authors: Riaz Muhammad Sohail , Zhao Siwei , Dong Chenlong , Nong Shuying , Zhao Yantao , Iqbal Muhammad Javed , Huang Fuqiang
Published: November 2019

Oxygen electrocatalysis is of remarkable significance for electrochemical energy storage and conversion technologies, together with fuel cells, metal‐air batteries, and water splitting devices. Substituting noble metal‐based electrocatalysts by decidedly effective and low‐cost metal‐based oxygen electrocatalysts is imperative for the commercial application of these technologies. Herein, a novel strategy is presented to fabricate selenized and phosphorized porous cobalt‐nickel oxide microcubes by using a sacrificial ZnO spherical template and the resulting microcubes are employed as an oxygen evolution reaction (OER) electrocatalyst. The selenized samples manifest desirable and robust OER performance, with comparable overpotential at 10 mA cm−2 (312 mV) as RuO2 (308 mV) and better activity when the current reaches 13.7 mA cm−2. The phosphorized samples exhibit core–shell structure with low‐crystalline oxides inside amorphous phosphides, which ensures superior activity than RuO2 with the same overpotential (at 10 mA cm−2) yet lower Tafel slope. Such a surface doping method possibly will provide inspiration for engineering electrocatalysts applied in water oxidation.
Micro/Nanoengineered α‐Fe2O3 Nanoaggregate Conformably Enclosed by Ultrathin N‐Doped Carbon Shell for Ultrastable Lithium Storage and Insight into Phase Evolution Mechanism
Authors: Xie Dan , Li Huan‐Huan , Shi Yan‐Hong , Diao Wan‐Yue , Jiang Ru , Sun Hai‐Zhu , Wu Xing‐Long , Li Wenliang , Fan Chao‐Ying , Zhang Jing‐Ping
Published: November 2019

The Fe‐based transition metal oxides are promising anode candidates for lithium storage considering their high specific capacity, low cost, and environmental compatibility. However, the poor electron/ion conductivity and significant volume stress limit their cycle and rate performances. Furthermore, the phenomena of capacity rise and sudden decay for α‐Fe2O3 have appeared in most reports. Here, a uniform micro/nano α‐Fe2O3 nanoaggregate conformably enclosed in an ultrathin N‐doped carbon network (denoted as M/N‐α‐Fe2O3@NC) is designed. The M/N porous balls combine the merits of secondary nanoparticles to shorten the Li+ transportation pathways as well as alleviating volume expansion, and primary microballs to stabilize the electrode/electrolyte interface. Furthermore, the ultrathin carbon shell favors fast electron transfer and protects the electrode from electrolyte corrosion. Therefore, the M/N‐α‐Fe2O3@NC electrode delivers an excellent reversible capacity of 901 mA h g−1 with capacity retention up to 94.0 % after 200 cycles at 0.2 A g−1. Notably, the capacity rise does not happen during cycling. Moreover, the lithium storage mechanism is elucidated by ex situ XRD and HRTEM experiments. It is verified that the reversible phase transformation of α↔γ occurs during the first cycle, whereas only the α‐Fe2O3 phase is reversibly transformed during subsequent cycles. This study offers a simple and scalable strategy for the practical application of high‐performance Fe2O3 electrodes.
Porous Molecular Capsules as Non‐Polymeric Transducers of Mechanical Forces to Mechanophores
Authors: Jędrzejewska Hanna , Wielgus Ewelina , Kaźmierski Sławomir , Rogala Halina , Wierzbicki Michał , Wróblewska Aneta , Pawlak Tomasz , Potrzebowski Marek J. , Szumna Agnieszka
Published: November 2019

Mechanical grinding/milling can be regarded as historically the first technology for changing the properties of matter. Mechanically activated molecular units (mechanophores) can be present in various structures: polymers, macromolecules, or small molecules. However, only polymers have been reported to effectively transduce energy to mechanophores, which induces breakage of covalent bonds. In this paper, a second possibility is presented—molecular capsules as stress‐sensitive units. Mechanochemical encapsulation of fullerenes in cystine‐based covalent capsules indicates that complexation takes place in the solid state, despite the fact that the capsules do not possess large enough entrance portals. By using a set of solvent‐free MALDI (sf‐MALDI) and solid‐state NMR (ss‐NMR) experiments, it has been proven that encapsulation proceeds during milling and in this process hydrazones and disulfides get activated for breakage, exchange, and re‐forming. The capsules are porous and therefore prone to collapse under solvent‐free conditions and their conformational rigidity promotes the collapse by the breaking of covalent bonds.
Ultrathin Films of Porous Metal–Organic Polyhedra for Gas Separation
Authors: Andrés Miguel A. , Carné‐Sánchez Arnau , Sánchez‐Laínez Javier , Roubeau Olivier , Coronas Joaquín , Maspoch Daniel , Gascón Ignacio
Published: November 2019

Ultrathin films of a robust RhII‐based porous metal–organic polyhedra (MOP) have been obtained. Homogeneous and compact monolayer films (ca. 2.5 nm thick) were first formed at the air–water interface, deposited onto different substrates and characterized using spectroscopic methods, scanning transmission electron microscopy and atomic force microscopy. As a proof of concept, the gas separation performance of MOP‐supported membranes has also been evaluated. Selective MOP ultrathin films (thickness ca. 60 nm) exhibit remarkable CO2 permeance and CO2/N2 selectivity, demonstrating the great combined potential of MOP and Langmuir‐based techniques in separation technologies.
Singly and Doubly Quinoxaline‐Fused BIII Subporphyrins
Authors: Kise Koki , Osuka Atsuhiro
Published: November 2019

B‐Phenyl BIII subporphyrin‐α‐diones prepared in a three‐step reaction sequence from the parent subporphyrin were condensed with 1,2‐diaminobenzenes to give the corresponding quinoxaline‐fused subporphyrins in variable yields. Quinoxaline‐fused B‐phenyl‐5,10,15‐triphenyl BIII subporphyrin was transformed to the corresponding subporphyrin‐α‐dione in the same three‐step reaction sequence, which was then condensed with 1,2‐diaminobenzene to give doubly quinoxaline‐fused subporphyrin. These quinoxaline‐fused subporphyrins exhibit redshifted absorption and fluorescence spectra compared with the parent one. A singly quinoxaline‐fused subporphyrin bearing three meso‐bis(4‐dimethylaminophenyl)aminophenyl substituents shows blueshifted fluorescence in less polar solvent, which has been ascribed to emission associated with charge recombination of intramolecular charge transfer (CT) state.
Molecular Acceptors Based on a Triarylborane Core Unit for Organic Solar Cells
Authors: Yu Yingjian , Meng Bin , Jäkle Frieder , Liu Jun , Wang Lixiang
Published: November 2019

Triarylboranes that exhibit p–π* conjugation serve as versatile building blocks to design n‐type organic/polymer semiconductors. A series of new molecular acceptors based on triarylborane is reported here. These molecules are designed with a boron atom that bears a bulky 2,4,6‐tri‐tert‐butylphenyl (Mes*) substituent at the core and strong electron‐withdrawing 2‐(3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (IC) units as the end‐capping groups that are linked to the core by bithiophene bridges. Butyl or butoxy groups are introduced to the bithiophene units to tune the optoelectronic properties. These molecules show nearly planar backbones with highly localized steric hindrance at the core, low LUMO/HOMO energy levels, and broad absorption bands spanning the visible region, which are all very desirable characteristics for use as electron acceptors in organic solar cell (OSC) applications. The attachment of butyl groups to the bithiophene bridges brings about a slightly twisted backbone, which in turn promotes good solubility and homogeneous donor/acceptor blend morphology, whereas the introduction of butoxy groups leads to improved planarity, favorable stacking in the film state, and a greatly reduced band gap. OSC devices based on these molecules exhibit encouraging photovoltaic performances with power conversion efficiencies reaching up to 4.07 %. These results further substantiate the strong potential of triarylboranes as the core unit of small molecule acceptors for OSC applications.
Strategies for Tumor Hypoxia Imaging Based on Aggregation‐Induced Emission Fluorogens
Authors: Xue Tianhao , Shen Jiajia , Shao Kuanchun , Wang Wei , Wu Bing , He Yaning
Published: November 2019

Hypoxia, as a crucial characteristic of cancer, has become an extremely significant direction for researchers to construct fluorescent probes for early diagnosis of tumors. Aggregation‐induced emission fluorogens (AIEgens) possess many superior properties to those of conventional fluorophores due to aggregation‐induced emission (AIE) features, such as a linear concentration‐dependent increase in brightness, remarkable resistance to photobleaching, and the long‐term tracking and imaging of cells. Constructing hypoxic response AIEgen‐based probes will be very useful for the early diagnosis of tumors. Herein, several hypoxia‐responsive probes based on AIEgens reported in the last three years are reported; these examples may lead to the construction of hypoxia‐responsive AIE probes used for tumor hypoxia imaging in the future. In addition, typical, conventional hypoxia‐responsive bioprobes are presented to further understand hypoxia‐responsive fluorescent probes based on AIEgens.
Using Peptide Arrays to Profile Phosphatase Activity in Cell Lysates
Authors: Szymczak Lindsey C. , Sykora Daniel J. , Mrksich Milan
Published: November 2019

Phosphorylation is an important post‐translational modification on proteins involved in many cellular processes; however, understanding of the regulation and mechanisms of global phosphorylation remains limited. Herein, we utilize self‐assembled monolayers on gold for matrix‐assisted laser desorption/ionization mass spectrometry (SAMDI‐MS) with three phosphorylated peptide arrays to profile global phosphatase activity in cell lysates derived from five mammalian cell lines. Our results reveal significant differences in the activities of protein phosphatases on phospho‐ serine, threonine, and tyrosine substrates and suggest that phosphatases play a much larger role in the regulation of global phosphorylation on proteins than previously understood.
Structural Characterization of a Series of N5‐Ligated MnIV‐Oxo Species
Authors: Massie Allyssa A. , Denler Melissa C. , Singh Reena , Sinha Arup , Nordlander Ebbe , Jackson Timothy A.
Published: November 2019

Analysis of extended X‐ray absorption fine structure (EXAFS) data for the MnIV‐oxo complexes [MnIV(O)(DMMN4py)]2+, [MnIV(O)(2pyN2B)]2+, and [MnIV(O)(2pyN2Q)]2+ (DMMN4py=N,N‐bis(4‐methoxy‐3,5‐dimethyl‐2‐pyridylmethyl)‐N‐bis(2‐pyridyl)methylamine; 2pyN2B=(N‐bis(1‐methyl‐2‐benzimidazolyl)methyl‐N‐(bis‐2‐pyridylmethyl)amine, and 2pyN2Q=N,N‐bis(2‐pyridyl)‐N,N‐bis(2‐quinolylmethyl)methanamine) afforded Mn=O and Mn−N bond lengths. The Mn=O distances for [MnIV(O)(DMMN4py)]2+ and [MnIV(O)(2pyN2B)]2+ are 1.72 and 1.70 Å, respectively. In contrast, the Mn=O distance for [MnIV(O)(2pyN2Q)]2+ was significantly longer (1.76 Å). We attribute this long distance to sample heterogeneity, which is reasonable given the reduced stability of [MnIV(O)(2pyN2Q)]2+. The Mn=O distances for [MnIV(O)(DMMN4py)]2+ and [MnIV(O)(2pyN2B)]2+ could only be well‐reproduced using DFT‐derived models that included strong hydrogen‐bonds between second‐sphere solvent 2,2,2‐trifluoroethanol molecules and the oxo ligand. These results suggest an important role for the 2,2,2‐trifluoroethanol solvent in stabilizing MnIV‐oxo adducts. The DFT methods were extended to investigate the structure of the putative [MnIV(O)(N4py)]2+⋅(HOTf)2 adduct. These computations suggest that a MnIV‐hydroxo species is most consistent with the available experimental data.
The “Inverted Bonds” Revisited: Analysis of “In Silico” Models and of [1.1.1]Propellane by Using Orbital Forces
Authors: Laplaza Rubén , Contreras‐Garcia Julia , Fuster Franck , Volatron François , Chaquin Patrick
Published: November 2019

This article dwells on the nature of “inverted bonds”, which refer to the σ interaction between two sp hybrids by their smaller lobes, and their presence in [1.1.1]propellane. Firstly, we study H3C−C models of C−C bonds with frozen H‐C‐C angles reproducing the constraints of various degrees of “inversion”. Secondly, the molecular orbital (MO) properties of [1.1.1]propellane and [1.1.1]bicyclopentane are analyzed with the help of orbital forces as a criterion of bonding/antibonding character and as a basis to evaluate bond energies. Triplet and cationic states of [1.1.1]propellane species are also considered to confirm the bonding/antibonding character of MOs in the parent molecule. These approaches show an essentially non‐bonding character of the σ central C−C interaction in propellane. Within the MO theory, this bonding is thus only due to π‐type MOs (also called “banana” MOs or “bridge” MOs) and its total energy is evaluated to approximately 50 kcal mol−1. In bicyclopentane, despite a strong σ‐type repulsion, a weak bonding (15–20 kcal mol−1) exists between both central C−C bonds, also due to π‐type interactions, though no bond is present in the Lewis structure. Overall, the so‐called “inverted” bond, as resulting from a σ overlap of the two sp hybrids by their smaller lobes, appears highly questionable.
Development and validation of an experimental and theoretical method for the chiral discrimination of dinotefuran
Authors: Silva Camilla Fonseca , Guimarães Luciana , Borges Keyller Bastos , Nascimento Clebio Soares
Published: November 2019

Dinotefuran is a low‐cost agrochemical considered a highly toxic product. In this sense, there is a need for its constant environmental, biological, and food control, aiming to ensure its use to humans as well as to preserve biodiversity and ecosystems. In the present work, we developed an experimental and theoretical method for dinotefuran chiral discrimination. According to the main results, the dinotefuran enantioselective separation was efficiently optimized by high‐performance liquid chromatography evaluating the influence of different percentage compositions in the mobile phase to improve the resolution of the peaks in the chromatogram. The novelty of this work was the proposition of a reduced molecular model for the chiral selector amylose‐Tris‐(3,5‐dimethylphenylcarbamate) polysaccharide that was able to adequately describe at the molecular level its interaction with the dinotefuran enantiomers. Besides, the thermodynamic and structural parameters obtained via density functional theory calculations pointed out the chiral discrimination as well as the enantiomeric elution order of the analyte studied, confirming the experimental data, thus validating our proposed method. Finally, hydrogen bonds and repulsive interactions played a key role in the discrimination between the diastereomeric complexes, and consequently, for the dinotefuran enantioselective separation.
Investigation of the chiral recognition ability of human carboxylesterase 1 using indomethacin esters
Authors: Takahashi Masato , Takani Daisuke , Haba Masami , Hosokawa Masakiyo
Published: November 2019

Human carboxylesterase 1 (hCES1) is an enzyme that plays an important role in hydrolysis of pharmaceuticals in the human liver. In this study, elucidation of the chiral recognition ability of hCES1 was attempted using indomethacin esters in which various chiral alcohols were introduced. Indomethacin was condensed with various chiral alcohols to synthesize indomethacin esters. The synthesized esters were hydrolyzed with a human liver microsome (HLM) solution and a human intestine microsome (HIM) solution. High hydrolytic rate and high stereoselectivity were confirmed in the hydrolysis reaction in the HLM solution but not in the HIM solution, and these indomethacin esters were thought to be hydrolyzed by hCES1. Next, these indomethacin esters were hydrolyzed in recombinant hCES1 solution and the hydrolysis rates of the esters were calculated. The stereoselectivity confirmed in HLM solution was also confirmed in the hCES1 solution. In the hydrolysis reaction of esters in which a phenyl group is bonded next to the ester, the Vmax value of the (R) form was 10 times larger than that of the (S) form.
Clinical, cytologic, and immunohistochemical features of sarcomas involving body cavity fluids
Authors: Chen Athena L. , Janko Elizabeth , Pitman Martha B. , Chebib Ivan
Published: November 2019

Background

Sarcomas are uncommon findings in body cavity fluids. Diagnosis may be challenging because sarcoma cells in fluids can round up and lose their characteristic appearance seen on smears and histologic sections. This study characterizes the cytologic features of sarcomas involving body cavity fluids.

Methods

Effusion fluids and cerebrospinal fluids diagnosed as positive for sarcoma were reviewed.

Results

Forty‐three fluids from 28 patients (median age, 47 years) were positive for sarcoma. Four patients who presented with positive fluids were alive at 1 to 10.7 years' follow‐up (median, 22.5 months). Twenty‐four patients died 2 days to 2 years (median, 19 days) after their positive fluid diagnoses. Twenty‐eight specimens from 20 patients had slides available for review. Although 18 of the 28 positive fluids had a morphology comparable to that of their primary, 4 small round blue cell tumors (SRBCTs) and 4 spindle cell tumors showed epithelioid morphology, 1 SRBCT had pleomorphic morphology, and 1 epithelioid primary had SRBCT morphology. Nine fluids had tumor cells in large, cohesive clusters mimicking carcinoma; workup was performed for 10, predominantly to rule out carcinoma and mesothelioma.

Conclusions

Sarcoma morphology may be altered in exfoliated cytology specimens. Workup on cell blocks aids in the differential diagnosis, especially for carcinoma and mesothelioma. Unsurprisingly, fluid cytology positive for sarcoma portends poor survival.
Modeling the hepatic arterial flow in living liver donor after left hepatectomy and postoperative boundary condition exploration
Authors: Ma Renfei , Hunter Peter , Cousins Will , Ho Harvey , Bartlett Adam , Safaei Soroush
Published: November 2019

Preoperative and postoperative hepatic perfusion is modeled with one‐dimensional (1‐D) Navier‐Stokes equations. Flow rates obtained from ultrasound (US) data and impedance resulted from structured trees are the inflow and outflow boundary condition (BC), respectively. Structured trees terminate at the size of the arterioles, which can enlarge their size after hepatectomy. In clinical studies, the resistance to pulsatile arterial flow caused by the microvascular bed can be reflected by the resistive index (RI), a frequently used index in assessing arterial resistance. This study uses the RI in a novel manner to conveniently obtain the postoperative outflow impedance from the preoperative impedance. The major emphasis of this study is to devise a model to capture the postoperative hepatic hemodynamics after left hepatectomy. To study this, we build a hepatic network model and analyze its behavior under four different outflow impedance: (a) the same as preoperative impedance; (b) evaluated using the RI and preoperative impedance; (c) computed from structured tree BC with increased radius of terminal vessels; and (d) evaluated using structured tree with both increased radius of root vessel, ie, the outlets of the postoperative hepatic artery, and increased radius of terminal vessels. Our results show that both impedance from (b) and (d) give a physiologically reasonable postoperative hepatic pressure range, while the RI in (b) allows for a fast approximation of postoperative impedance. Since hemodynamics after hepatectomy are not fully understood, the methods used in this study to explore postoperative outflow BC are informative for future models exploring hemodynamic effects of partial hepatectomy.
Population‐specific modelling of between/within‐subject flow variability in the carotid arteries of the elderly
Authors: Lassila Toni , Sarrami‐Foroushani Ali , Hejazi SeyedMostafa , Frangi Alejandro F.
Published: November 2019

Computational fluid dynamics models are increasingly proposed for assisting the diagnosis and management of vascular diseases. Ideally, patient‐specific flow measurements are used to impose flow boundary conditions. When patient‐specific flow measurements are unavailable, mean values of flow measurements across small cohorts are used as normative values. In reality, both the between‐subjects and within‐subject flow variabilities are large. Consequently, neither one‐shot flow measurements nor mean values across a cohort are truly indicative of the flow regime in a given person. We develop models for both the between‐subjects and within‐subject variability of internal carotid flow. A log‐linear mixed effects model is combined with a Gaussian process to model the between‐subjects flow variability, while a lumped parameter model of cerebral autoregulation is used to model the within‐subject flow variability in response to heart rate and blood pressure changes. The model parameters are identified from carotid ultrasound measurements in a cohort of 103 elderly volunteers. We use the models to study intracranial aneurysm flow in 54 subjects under rest and exercise and conclude that OSI, a common wall shear‐stress derived quantity in vascular CFD studies, may be too sensitive to flow fluctuations to be a reliable biomarker.
Precise Control of Molecular Self‐Diffusion in Isoreticular and Multivariate Metal‐Organic Frameworks
Authors: Osborn Popp Thomas M. , Plantz Ariel Z. , Yaghi Omar M. , Reimer Jeffrey A.
Published: November 2019

Understanding the factors that affect self‐diffusion in isoreticular and multivariate (MTV) MOFs is key to their application in drug delivery, separations, and heterogeneous catalysis. Here, we measure the apparent self‐diffusion of solvents saturated within the pores of large single crystals of MOF‐5, IRMOF‐3 (amino‐functionalized MOF‐5), and 17 MTV‐MOF‐5/IRMOF‐3 materials at various mole fractions. We find that the apparent self‐diffusion coefficient of N,N‐dimethylformamide (DMF) may be tuned linearly between the diffusion coefficients of MOF‐5 and IRMOF‐3 as a function of the linker mole fraction. We compare a series of solvents at saturation in MOF‐5 and IRMOF‐3 to elucidate the mechanism by which the linker amino groups tune molecular diffusion. The ratio of the self‐diffusion coefficients for solvents in MOF‐5 to those in IRMOF‐3 is similar across all solvents tested, regardless of solvent polarity. We conclude that average pore aperture, not solvent‐linker chemical interactions, is the primary factor responsible for the different diffusion dynamics upon introduction of an amino group to the linker.
A differentiation program induced by bone morphogenetic proteins 4 and 7 in endodermal epithelial cells provides the molecular basis for efficient nutrient transport by the chicken yolk sac
Authors: Bauer Raimund , Tondl Philipp , Schneider Wolfgang J.
Published: November 2019

Background

The mammalian yolk sac provides nutrients for the growing fetus during critical early developmental processes such as neural tube closure, which precedes the functional maturation of the placenta. In contrast, oviparous species such as the chicken rely solely on the yolk sac for transfer of nutrients from the yolk to the developing embryo. However, the molecular mechanisms that provide the yolk sac with nutrient transfer competence remain poorly understood.

Results

We demonstrate that the chicken endodermal epithelial cells (EEC), which are in close contact with the yolk, gain their nutrient‐transport competence by a paracrine crosstalk with the blood‐vessel forming mesodermal cell layer. Bone morphogenetic proteins (BMP) 4 and 7 produced by ectodermal and mesodermal cell layers likely initiate a differentiation program of EECs during the transition from the area vitellina to the area vasculosa. BMPs, by inducing SMAD signaling, promote the up‐regulation of endocytic receptor expression and thereby provide the EECs with the molecular machinery to produce triglyceride‐rich lipoprotein particles.

Conclusion

This paracrine signaling cascade may constitute the basis for the EEC‐mediated mechanism underlying the efficient uptake, degradation, resynthesis, and transfer of yolk‐derived nutrients into the embryonic circulation, which assures proper energy supply and development of the growing fetus.
Microsatellite‐based analysis of genetic structure and gene flow ofMythimna separata(Walker) (Lepidoptera: Noctuidae) in China
Authors: Li Mei‐Mei , Li Bo‐Liao , Jiang Shi‐Xiong , Zhao Yu‐Wan , Xu Xiang‐Li , Wu Jun‐Xiang
Published: November 2019

The oriental armyworm,Mythimna separata, is a serious agricultural pest in China. Seasonal and roundtrip migration has recently led to sudden, localized outbreaks and crop losses. To evaluate genetic differentiation between populations in eastern and western China and elucidate gene flow, the genetic structure of 20 natural populations from nine provinces was examined using seven microsatellite markers. The results indicated high genetic diversity. However, little to moderate (0 < FST < 0.15) genetic differentiation was detected, and there was no correlation between genetic distance and geographical distance. Bayesian clustering analysis identified three groups whereas discriminant analysis of principal components identified ten clusters that were considered as two clear‐cut clusters and one admixed group. Gene flow occurred frequently in most population pairs, and an asymmetrical migration rate was detected in several pairwise population comparisons. The bottleneck test showed that few populations had experienced recent bottlenecks. Correspondingly, large‐scale and long‐distance migration ofM. separatahas caused low genetic differentiation and frequent gene exchange. Our findings are important for studying genetic evolution and help to improve predictions ofM. separataoutbreaks in China.
External disturbances impact helminth–host interactions by affecting dynamics of infection, parasite traits, and host immune responses
Authors: Cattadori Isabella M. , Pathak Ashutosh K. , Ferrari Matthew J.
Published: November 2019

External perturbations, such as multispecies infections or anthelmintic treatments, can alter host–parasite interactions with consequences on the dynamics of infection. While the overall profile of infection might appear fundamentally conserved at the host population level, perturbations can disproportionately affect components of parasite demography or host responses, and ultimately impact parasite fitness and long‐term persistence.

We took an immuno‐epidemiological approach to this reasoning and examined a rabbit–helminth system where animals were trickle‐dosed with either one or two helminth species, treated halfway through the experiment with an anthelmintic and reinfected one month later following the same initial regime. Parasite traits (body length and fecundity) and host immune responses (cytokines, transcription factors, antibodies) were quantified at fixed time points and compared before and after drug treatment, and between single and dual infections.

Findings indicated a resistant host phenotype toTrichostrongylus retortaeformiswhere abundance, body length, and fecundity were regulated by a protective immune response. In contrast,Graphidium strigosumaccumulated in the host and, while it stimulated a clear immune reaction, many genes were downregulated both following reinfection and in dual infection, suggestive of a low host resistance.

External perturbations affected parasite fecundity, including body length and number of eggs in utero, more significantly than abundance; however, there was no consistency in the parasite‐immune relationships.

Disentangling the processes affecting parasite life history, and how they relate to host responses, can provide a better understanding of how external disturbances impact disease severity and transmission, and how parasites strategies adjust to secure persistence at the host and the population level.
Resource selection of mule deer in a shrub‐steppe ecosystem: influence of woodland distribution and animal behavior
Authors: Morano Sabrina , Stewart Kelley M. , Dilts Thomas , Ellsworth Alisa , Bleich Vernon C.
Published: November 2019

Ungulates inhabiting arid ecosystems are reliant on productive forb and shrub communities during summer months to meet nutritional demands for survival and reproduction. In the western United States, expansion of woodland vegetation into shrub‐dominated communities and the potential loss of habitat are of concern with regard to animal populations reliant on robust sagebrush shrub and forb vegetation. We used mixed‐effects logistic regression to model resource selection of female mule deer (Odocoileus hemionus) during the summers of 2005–2008. We considered selection at two spatial scales, and during three daily activity periods (night, crepuscular, and mid‐day) corresponding to resting and foraging. We evaluated habitat variables related to vegetation type, site productivity, terrain attributes, and fine‐scale abundance of pinyon–juniper cover. Those attributes allowed us to account for variation in site productivity and animal behaviors that could obscure the true relationship between density of pinyon–juniper woodland and habitat use by mule deer. We detected observable differences in habitat use by mule deer among the three activity periods with significant differences in movement rates. Deer were most active during crepuscular periods corresponding with foraging activity, and least active mid‐day when temperatures were highest. Summer habitat consisted of sites with high potential productivity, greater shrub abundance, and greater proximity to riparian areas. Deer avoided high levels of tree cover (>40% coverage) at all spatial and temporal scales, and in general selection declined with increasing pinyon–juniper cover, particularly during foraging periods. Nonetheless, mule deer selected areas with low to intermediate tree cover (10% to 40%) during resting periods and avoided areas of productive shrub and forb vegetation and riparian areas, when surrounded by denser stands of pinyon–juniper cover. These results emphasize the importance of productive shrub and forb vegetation to mule deer inhabiting semi‐arid regions and suggest that low levels of tree cover are beneficial, especially during resting periods. Nevertheless, dense pinyon–juniper cover was generally avoided even in areas of high site productivity. These relationships lend support to the concern that increases in large, dense stands of pinyon–juniper reduce availability of summer habitat and alter patterns of resource selection for mule deer, a shrub‐dependent ungulate.
Web of interactions among diversity approaches to identify ecosystem essential variables: Negev Highlands case study
Authors: Dor‐Haim Shayli , Orenstein Daniel E. , Shachak Moshe
Published: November 2019

The concept of ecosystem diversity essential variables (EEVs) offers a foundation for ecosystem studies. Identification of EEVs continues to be a challenge in the field of ecology, due to the lack of a conceptual and applied framework. This paper develops a conceptual framework, offering theoretical foundation and a methodology for identifying EEVs, reflecting essential biodiversity and geodiversity variables. We start with a conceptual model of ecosystem essential variables linking biodiversity and geodiversity processes into ecosystem diversity as a web of interactions (WoI). The WoI components and interactions enable the identification of EEVs and their essentiality by relating interactions among diversities to variables that identify them. We tested our conceptual pass way by analyzing drivers and feedbacks of ecosystem processes in the Negev Highlands. Based on the general models and research of the Negev Highlands, we present four steps for EEVs: (1) developing a general conceptual model of the abiotic and biotic components of the ecosystem that links both biodiversity and geodiversity and their interactions; (2) testing the validity of the general model for a specific ecosystem to find out the hydro‐geo‐ecological drivers and feedbacks controlling ecosystem diversity; (3) constructing a WoI that adds to the regular analysis of an ecosystem as an interaction among geodiversity and biodiversity by breaking down the two components of diversities into subcomponent and their interactions; and (4) translating of the WoI components and interactions to EEVs. We suggest that EEVs should be related not only to the components but also to the interactions among diversities. These steps are essential for developing a scientific framework that allows for systematic identification of EEVs and justification regarding the final selection of the essential variables. We suggest that the approach can potentially be applied to all global terrestrial system.
Stream network geometry and the spatial influence of aquatic insect subsidies across the contiguous United States
Authors: Kopp Darin A. , Allen Daniel C.
Published: November 2019

Emergent aquatic insects transport aquatic‐derived resources into terrestrial ecosystems but are rarely studied at landscape or regional scales. Here, we investigate how stream network geometry constrains the spatial influence of aquatic insect subsidies in terrestrial ecosystems. We also explore potential factors (i.e., climate, topography, soils, and vegetation) that could produce variation in stream network geometry and thus change the extent of aquatic insect subsidies from one region to another. The stream signature is the percentage of aquatic insect subsidies traveling a given distance into the terrestrial ecosystem, relative to what comes out of the stream. We use this concept to model the spatial extent (area) and distribution (spatial patterning) of aquatic subsidies in terrestrial ecosystems across the contiguous United States. Our findings suggest that at least 8% of the subsidies measured at the aquatic–terrestrial boundary (i.e., the 8% stream signature) are typically transferred throughout the entire watershed and that variation in this spatial extent is largely influenced by the drainage density of the stream network. Moreover, we found stream signatures from individual stream reaches overlap such that the spatial extent of the 8% stream signature often includes inputs from multiple stream reaches. Landscape‐scale stream network characteristics increased the area of overlapping stream signatures more than reach‐scale channel properties. Finally, we found runoff was an important factor influencing stream network geometry suggesting a potential effect of climate on aquatic‐to‐terrestrial linkages that have been understudied.