bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and Bait Preference of Black Rat (Rattus rattus) in the University Community in Nigeria: Obafemi Awolowo University as a Case Study
Authors: Bamidele A. O. , Kowobari E. D.
Published: December 2019

Aims: This study assessed the morphology and the bait preference of black rat (Rattus rattus) in Obafemi Awolowo University student hostel with the aim of controlling the population of black rat in the students’ hostels.

Place and Duration of the Study: The study was carried out at Obafemi Awolowo University which is situated in Ile-Ife, an ancient city in the Southwestern Nigeria and lies between latitudes 7°28′N and 7.467°N and longitudes 4°34′E and 4.567°Ewith a landmass of 5,506 hectares between December 2017 and February 2018

Methodology: Locally made metal traps (cage traps) (Plate 1) contains baits were placed fortnightly in various sampling locations (Awolowo, Fajuyi, Angola, Akintola, Mozambique and Moremi halls of residence) for a period of 3 months between the months of December 2017 to February 2018. The traps were set around the dark corners of the sites in the evening and collected the following morning (6.00am).

Results: A total of 236 black rats (Rattus rattus) were caught (81 male & 155 female), with the female having the highest weight (238.30 g). Among the baits used, fried fish caught the highest number of the black rat (58%) followed by beans cake (akara) (28%) and the locust bean (14%). There was a positive correlation in the morphology of the black rat caught in all the hostels.

Conclusion: The black rats in the University student hall of residence were of the same family and genus, and fried fish is the best-preferred bait.
A New Generalization of Jacobsthal Lucas Numbers (Bi-Periodic Jacobsthal Lucas Sequence)
Authors: Uygun Sukran , Owusu Evans
Published: January 2020

In this study, we bring into light a new generalization of the Jacobsthal Lucas numbers, which shall also be called the bi-periodic Jacobsthal Lucas sequence as

 

with initial conditions $$\ \hat{c}_{0}=2,\ \hat{c}_{1}=a.$$

The Binet formula as well as the generating function for this sequence are given. The convergence property of the consecutive terms of this sequence is examined after which the well known Cassini, Catalan and the D'ocagne identities as well as some related summation formulas are also given.
Dimerization of small integral membrane protein 1 promotes cell surface presentation of the Vel blood group epitope
Authors: Kelley Liam P. , Nylander Anja , Arnaud Lionel , Schmoker Anna M. , St. Clair Riley M. , Gleason Lindsey A. , Souza Jessica M. , Storry Jill R. , Olsson Martin L. , Ballif Bryan A.
Published: December 2019

The Vel blood group antigen is carried on the short extracellular segment of the 78‐amino‐acid‐long, type II transmembrane protein SMIM1 of unknown function. Here, using biochemical analysis and flow cytometry of cells expressing wild‐type and mutant alleles of SMIM1, we demonstrate that dimerization of SMIM1 promotes cell surface display of the Vel epitope. We show that SMIM1 dimerization is mediated both by an extracellular Cys77‐dependent, homomeric disulfide linkage and via a GxxxG helix–helix interaction motif in the transmembrane domain. These results provide important context for the observed variability in reactivity patterns of clinically important anti‐Vel identified in patient sera.
A Single Noninterleaved Metasurface for High‐Capacity and Flexible Mode Multiplexing of Higher‐Order Poincaré Sphere Beams
Authors: Jiang Zhi Hao , Kang Lei , Yue Taiwei , Xu He‐Xiu , Yang Yuanjie , Jin Zhongwei , Yu Changyuan , Hong Wei , Werner Douglas H. , Qiu Cheng‐Wei
Published: December 2019

Cylindrical vector vortex beams, a particular class of higher‐order Poincaré sphere beams, are generalized forms of waves carrying orbital angular momentum with inhomogeneous states‐of‐polarization on their wavefronts. Conventional methods as well as the more recently proposed segmented/interleaved shared‐aperture metasurfaces for vortex beam generation are either severely limited by bulky optical setups or by restricted channel capacity with low efficiency and mode number. Here, a noninterleaved vortex multiplexing approach is proposed, which utilizes superimposed scattered waves with opposite spin states emanating from all meta‐atoms in a coherent manner, counter‐intuitively enabling ultrahigh‐capacity, high‐efficiency, and flexible generation of massive vortex beams with structured state‐of‐polarization. A series of exemplary prototypes, implemented by sub‐wavelength‐thick metasurfaces, are demonstrated experimentally, achieving kaleidoscopic vector vortex beams. This methodology holds great promise for structured wavefront shaping, vortex generation, and high information‐capacity planar photonics, which may have a profound impact on transformative technological advances in fields including spin‐Hall photonics, optical holography, compressive imaging, electromagnetic communication, and so on.
Suppressing Vacancy Defects and Grain Boundaries via Ostwald Ripening for High‐Performance and Stable Perovskite Solar Cells
Authors: Yang Yuqian , Wu Jihuai , Wang Xiaobing , Guo Qiyao , Liu Xuping , Sun Weihai , Wei Yuelin , Huang Yunfang , Lan Zhang , Huang Miaoliang , Lin Jianming , Chen Hongwei , Wei Zhanhua
Published: December 2019

As one kind of promising next‐generation photovoltaic devices, perovskite solar cells (PVSCs) have experienced unprecedented rapid growth in device performance over the past few years. However, the practical applications of PVSCs require much improved device long‐term stability and performance, and internal defects and external humidity sensitivity are two key limitation need to be overcome. Here, gadolinium fluoride (GdF3) is added into perovskite precursor as a redox shuttle and growth‐assist; meanwhile, aminobutanol vapor is used for Ostwald ripening in the formation of the perovskite layer. Consequently, a high‐quality perovskite film with large grain size and few grain boundaries is obtained, resulting in the reduction of trap state density and carrier recombination. As a result, a power conversion efficiency of 21.21% is achieved with superior stability and negligible hysteresis.
Tailoring and Modifying an Organic Electron Acceptor toward the Cathode Interlayer for Highly Efficient Organic Solar Cells
Authors: Liao Qing , Kang Qian , Yang Yi , An Cunbin , Xu Bowei , Hou Jianhui
Published: December 2019

With the rapid advance of organic photovoltaic materials, the energy level structure, active layer morphology, and fabrication procedure of organic solar cells (OSCs) are changed significantly. Thus, the photoelectronic properties of many traditional electrode interlayers have become unsuitable for modifying new active layers; this limits the further enhancement in OSC efficiencies. Herein, a new design strategy of tailoring the end‐capping unit, ITIC, to develop a cathode interlayer (CIL) material for achieving high power conversion efficiency (PCE) in OSCs is demonstrated. The excellent electron accepting capacity, suitable energy level, and good film‐forming ability endow the S‐3 molecule with an outstanding electron extraction property. A device with S‐3 shows a PCE of 16.6%, which is among the top values in the field of OSCs. More importantly, it is demonstrated that the electrostatic potential difference between the CIL molecule and the polymer donor plays a crucial role in promoting exciton dissociation at the CIL/active layer interface, contributing to additional charge generation; this is crucial for enhancement of the current density. The results of this work not only develop a new design strategy for high‐performance CIL, but also demonstrate a reliable approach of density functional theory (DFT) calculation to predict the effect of the CIL chemical structure on exciton dissociation in OSCs.
Highly Porous, Biocompatible Tough Hydrogels, Processable via Gel Fiber Spinning and 3D Gel Printing
Authors: Naficy Sina , Le Thi Yen Loan , Oveissi Farshad , Lee Aeryne , Hung Jui Chien , Wise Steven G. , Winlaw David S. , Dehghani Fariba
Published: December 2019

Conventional tough hydrogels offer enhanced mechanical properties and high toughness. Their application scope however is limited by their lack of processability. Here, a new porous tough hydrogel system is introduced which is processable via gel fiber spinning and 3D printing. The tough hydrogels are produced by rehydrating processable organogels developed by induced phase separation between two linear polymer chains capable of intermolecular hydrogen bonding. Through a slow sol–gel phase separation, highly porous gel networks made of hydrogen bonded polymer chains is formed. These organogels can be easily transformed to 3D printed multimaterial constructs or gel fibers, and after rehydration produce highly robust hydrogel structures. Although such hydrogels are highly porous and contain large amount of water, their strength can reach as high as 2000 kPa, with high elongation at break (≈900%), and tunable moduli ranging from 250 to 2000 kPa. The hydrogels have fracture energies larger than cartilage and demonstrate excellent load recovery because of their renewable hydrogen bond crosslinks. Furthermore, the hydrogels exhibit excellent hemocompatibility and in vitro biocompatibility. Such hydrogels can further expand the application of tough hydrogels and may serve as a model to explore the toughening mechanism of hydrogen bonded hybrid, tough hydrogel systems.
Continuous fluidized bed drying: Residence time distribution characterization and effluent moisture content prediction
Authors: Chen Hao , Diep Emily , Langrish Timothy A. G. , Glasser Benjamin J.
Published: December 2019

The mixing and drying behavior in a continuous fluidized bed dryer were investigated experimentally by characterizing the residence time distribution (RTD) and incorporating a micromixing model together with the drying kinetics obtained from batch drying. The RTD of the dryer was modeled using a tank‐in‐series model. It was found that a high initial material loading and a low material flow rate resulted in a reduced peak height and broaded peak width of the RTD curve. To predict the continuous dryer effluent moisture content, we combined: (a) the drying kinetics as determined in a batch fluidized bed dryer, (b) the RTD model, and (c) micromixing models—segregation and maximum mixedness models. It was found that the segregation model overpredicted the effluent moisture content by up to 5% for the cases we have studied while the maximum mixedness model gave a good prediction of the effluent moisture content.
Carbene‐Catalyzed Dynamic Kinetic Resolution and Asymmetric Acylation of Hydroxyphthalides and Related Natural Products
Authors: Liu Yingguo , Majhi Pankaj Kumar , Song Runjiang , Mou Chengli , Hao Lin , Chai Huifang , Jin Zhichao , Chi Yonggui Robin
Published: December 2019

A catalytic dynamic kinetic resolution and asymmetric acylation reaction of hydroxyphthalides is developed. The reaction involves formation of a carbene catalyst derived chiral acyl azolium intermediate that effectively differentiates the two enantiomers of racemic hydroxyphthalides. The method allows quick access to enantiomerically enriched phthalidyl esters with proven applications in medicine. It also enables asymmetric modification of natural products and other functional molecules that contain acetal/ketal groups, such as corollosporine and fimbricalyxlactone C.
Branching Regulation in Olefin Polymerization via Lewis Acid Triggered Isomerization of Monomers
Authors: Basbug Alhan Hatice E. , Jones Glen R. , Harth Eva
Published: December 2019

We present a new strategy to regulate branching in chain‐walking olefin polymerization by triggering a rapid isomerization of 1‐alkene monomers into internal olefins by adding a Lewis acid. Polymerization of internal alkenes proceeds via chain‐walking to give polymers with much higher branching than 1‐alkene analogues. The utility of this approach is exemplified by synthesis of well‐defined block copolymers with distinct branching characteristics per block by addition of Lewis acid midway through a reaction. We propose a novel mechanism whereby Lewis acid undergoes a counterion swap with the complex which favors isomerization as well as forming adducts with ancillary ligands, freeing coordination sites for internal alkene coordination polymerization.
Photocontrolled Iodine‐Mediated Reversible‐Deactivation Radical Polymerization: Solution Polymerization of Methacrylates by Irradiation with NIR LED Light
Authors: Tian Chun , Wang Peng , Ni Yuanyuan , Zhang Lifen , Cheng Zhenping , Zhu Xiulin
Published: December 2019

Herein, near‐infrared (NIR) photocontrolled iodide‐mediated reversible‐deactivation radical polymerization (RDRP) of methacrylates, without an external photocatalyst, was developed using an alkyl iodide (e.g., 2‐iodo‐2‐methylpropionitrile) as the initiator at room temperature. This example is the first use of a series of special solvents containing carbonyl groups (e.g., 1,3‐dimethyl‐2‐imidazolidinone) as both solvent and catalyst for photocontrolled RDRP using long‐wavelength (λmax=730 nm) irradiation. The polymerization system comprises monomer, alkyl iodide initiator, and solvent. Well‐defined polymers were synthesized with excellent control over the molecular weights and molecular weight distributions (Mw/Mn<1.21). The living features of this system were confirmed by polymerization kinetics, multiple controlled “on‐off” light switching cycles, and chain extension experiments. Importantly, the polymerizations proceeded successfully with various barriers (pork skin and A4 paper), demonstrating the advantage of high‐penetration NIR light.
Chiral Overpass Induction in Dynamic Helical Polymers Bearing Pendant Groups with Two Chiral Centers
Authors: Suárez‐Picado Esteban , Quiñoá Emilio , Riguera Ricardo , Freire Félix
Published: December 2019

The dynamic behavior of helical polymers bearing pendant groups with two chiral centers was studied. Controlled conformational changes at the chiral units placed either closer to or further away from the main chain promote different helical structures. Although the first residue is usually responsible for determining a specific helicity (P or M), we now found that the second chiral center is also able to induce a preferred helical sense when it is located closer in space to the main chain, thereby cancelling the order from the first chiral moiety. This result was achieved through proper coordination with a metal cation. As proof of concept, poly(phenylacetylene)s (PPAs) that bear one and two chiral amino acid units of different sizes and configuration combinations (l/d‐alanine and l/d‐phenylalanine) as pendants were evaluated. In total, ten polymers were studied. This constitutes the first report of axial control from a remote stereocenter in polymers bearing complex chiral pendants.
Highly Mesoporous Metal‐Organic Frameworks as Synergistic Multimodal Catalytic Platforms for Divergent Cascade Reactions
Authors: Dutta Soumen , Kumari Nitee , Dubbu Sateesh , Jang Sun Woo , Kumar Amit , Ohtsu Hiroyoshi , Kim Junghoon , Cho Seung Hwan , Kawano Masaki , Lee In Su
Published: December 2019

Rational engineering and assimilation of diverse chemo‐ and biocatalytic functionalities in a single nanostructure is highly desired for efficient multistep chemical reactions but has so far remained elusive. Here, we design and synthesize multimodal catalytic nanoreactors (MCNRs) based on a mesoporous metal‐organic framework (MOF). The MCNRs consist of customizable metal nanocrystals and stably anchored enzymes in the mesopores, as well as coordinatively unsaturated cationic metal MOF nodes, all within a single nanoreactor space. The highly intimate and diverse catalytic mesoporous microenvironments and facile accessibility to the active site in the MCNR enables the cooperative and synergistic participation from different chemo‐ and biocatalytic components. This was shown by one‐pot multistep cascade reactions involving a heterogeneous catalytic nitroaldol reaction followed by a [Pd/lipase]‐catalyzed chemoenzymatic dynamic kinetic resolution to yield optically pure (>99 % ee) nitroalcohol derivatives in quantitative yields.
Redox‐Active Ligand Assisted Catalytic Water Oxidation by a RuIV=O Intermediate
Authors: Shi Jing , Guo Yu‐Hua , Xie Fei , Chen Qi‐Fa , Zhang Ming‐Tian
Published: December 2019

Water splitting is one of the most promising solutions for storing solar energy in a chemical bond. Water oxidation is still the bottleneck step because of its inherent difficulty and the limited understanding of the O−O bond formation mechanism. Molecular catalysts provide a platform for understanding this process in depth and have received wide attention since the first Ru‐based catalyst was reported in 1982. RuV=O is considered a key intermediate to initiate the O−O bond formation through either a water nucleophilic attack (WNA) pathway or a bimolecular coupling (I2M) pathway. Herein, we report a Ru‐based catalyst that displays water oxidation reactivity with RuIV=(O) with the help of a redox‐active ligand at pH 7.0. The results of electrochemical studies and DFT calculations disclose that ligand oxidation could significantly improve the reactivity of RuIV=O toward water oxidation. Under these conditions, sustained water oxidation catalysis occurs at reasonable rates with low overpotential (ca. 183 mV).
Enabling High‐Voltage Lithium Metal Batteries by Manipulating Solvation Structure in Ester Electrolyte
Authors: Jie Yulin , Liu Xiaojing , Lei Zhanwu , Wang Shiyang , Chen Yawei , Huang Fanyang , Cao Ruiguo , Zhang Genqiang , Jiao Shuhong
Published: December 2019

Lithium metal is an ideal electrode material for future rechargeable lithium metal batteries. However, the widespread deployment of metallic lithium anode is significantly hindered by its dendritic growth and low Coulombic efficiency, especially in ester solvents. Herein, by rationally manipulating the electrolyte solvation structure with a high donor number solvent, enhancement of the solubility of lithium nitrate in an ester‐based electrolyte is successfully demonstrated, which enables high‐voltage lithium metal batteries. Remarkably, the electrolyte with a high concentration of LiNO3 additive presents an excellent Coulombic efficiency up to 98.8 % during stable galvanostatic lithium plating/stripping cycles. A full‐cell lithium metal battery with a lithium nickel manganese cobalt oxide cathode exhibits a stable cycling performance showing limited capacity decay. This approach provides an effective electrolyte manipulation strategy to develop high‐voltage lithium metal batteries.
Photoinduced Proton‐Transfer Reactions for Mild O‐H Functionalization of Unreactive Alcohols
Authors: Jana Sripati , Yang Zhen , Li Fang , Empel Claire , Ho Junming , Koenigs Rene M.
Published: December 2019

Hexafluoroisopropanol is typically considered as an unreactive solvent and not as a reagent in organic synthesis. Herein, we report on a mild and efficient photochemical reaction of aryl diazoacetates with hexafluoroisopropanol that enables, under stoichiometric reaction conditions, the synthesis of fluorinated ethers in excellent yield. Mechanistic studies indicate there is a preorganization of hexafluoroisopropanol and the diazoalkane acts as an unreactive hydrogen‐bonding complex. Only after photoexcitation does this complex undergo a protonation‐substitution reaction to the reaction product. Investigations on the applicability of this photochemical transformation show that a broad variety of acidic alcohols can be subjected to this transformation and thus demonstrate the feasibility of this concept for O‐H functionalization reactions (54 examples, up to 98 % yield).
Esterified PVA‐lignin resin by maleic acid applicable for natural fiber reinforced composites
Authors: Ko Hyun‐U , Kim Jung W. , Kim Hyun C. , Zhai Lindong , Kim Jaehwan
Published: December 2019

This article reports an esterified polyvinyl alcohol (PVA)‐lignin resin that is applicable for natural fiber reinforced polymer composites. To meet the requirement for the composites, a biopolymer‐based resin is necessary, which should well interact with the natural fiber with good waterproof behavior. By mimicking the relationship between cellulose, lignin and hemicellulose in wood, the esterified PVA‐lignin resin with maleic acid is provided. The preparation and characterization of the environment‐friendly resin are illustrated in this article. 180 °C of esterification reaction temperature and 40% of maleic acid contents are shown to be an optimum condition for the preparation of the resin. The esterified PVA‐lignin resin exhibits 13, 31, and 55% increase of its tensile strength, toughness, and failure strength, respectively. The water contact angle of the esterified PVA‐lignin resin is improved from 0 to 57°. The prepared resin is originally thermoplastic composite and it turned to be a thermoset resin by the esterification reaction at 180 °C, which is beneficial for composite processing. The developed resin is applicable for environment‐friendly and high strength‐natural fiber reinforced polymer composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48836.
Flexible and transparent polymer/cellulose nanocrystal nanocomposites with high thermal conductivity for thermal management application
Authors: Wu Xinfeng , Gao Yuan , Yao Hang , Sun Kai , Fan Runhua , Li Xiaofeng , An Yan , Lei Yanhua , Zhang Yuliang
Published: December 2019

Polymeric materials play important roles in semiconductor technology and modern electronic devices. However, the weak thermal management capability of polymer seriously restricts the service life, reliability, and efficiency of devices. Consequently, inorganic or metallic thermally conductive fillers are added into polymers to make up the low thermal conductivity, but the optical transparency and flexibility always decrease or even disappear. Herein, we report transparent polymer nanocomposites comprising poly(vinyl alcohol) (PVA) and cellulose nanocrystal (CNC) with highly lateral thermal conductivity [about 5.7 W/(m·K)]. Such a high thermal conductivity is attributed to the aligned structure of CNC in PVA matrix and hydrogen‐bond interaction between CNC and PVA. All the organic nanocomposites also present excellent electrical insulating performance and tensile properties. The transparent and flexible nanocomposites are promising in the thermal management applications of displays, next‐generation wearable devices, sensors, and LEDs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48864.
Metagenomic insights into bioaugmentation and biovalorization of oily industrial wastes by lipolytic oleaginous yeast Yarrowia lipolytica during successive batch fermentation
Authors: Louhasakul Yasmi , Cheirsilp Benjamas , Treu Laura , Kougias Panagiotis G. , Angelidaki Irini
Published: December 2019

The lipolytic oleaginous yeast Yarrowia lipolytica was used in the bioaugmentation and biovalorization of oily industrial wastes during successive‐batch fermentation. Five cycles of nonsterile successive batch fermentation with 70% medium replacement achieved the highest oil removal of 68.1 ± 5.60% and produced biomass and lipid yields of 0.213 ± 0.07 g/g‐COD and 146.2 ± 46.5 mg/g‐COD, respectively. The cell‐bound lipase activity observed in the system was 170.74 ± 32 U/L. The auto‐flocculation efficiency of the biomass was >90% within 60 Min. The microbial community changes between Y. lipolytica and indigenous microorganisms were monitored by metagenomic next‐generation sequencing of internal transcribed spacer rDNA regions for yeasts and 16S rRNA gene for bacteria. Ylipolytica lipolytica was retained in the consortium together with other indigenous strains until the fifth cycle. Other minor oleaginous yeasts such as Kodamaea ohmeri and Candida tropicalis as well as polyhydroxyalkanoate‐accumulating bacteria were found and are likely to have participated in lipid production. This study has shown the robustness of Y. lipolytica in nonsterile successive batch fermentation and its use could contribute greatly to the practical valorization of industrial wastes for lipids and lipases.
Electrodeposited Manganese Oxide on Carbon Paper for Zinc‐Ion Battery Cathodes
Authors: Dhiman Arjun , Ivey Douglas G.
Published: December 2019

Nano‐crystalline, flake‐like Mn oxide was electrodeposited onto carbon paper (CP) using a pulsed electrodeposition technique. The electrodeposited Mn oxide was identified as Mn3O4 through a combination of X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), and Raman spectroscopy. The Mn3O4 on CP was used as a cathode for Zn‐ion batteries (ZIBs) and showed excellent cyclability at a current density of 1 A g−1 with a capacity retention of 139 % after 200 cycles. Electron microscopy was used to characterize the microstructural changes of the cathode at various stages during discharge/charge cycling. This work in combination with the electrochemical results suggests a two‐step reaction mechanism involving both intercalation and conversion reactions. The results demonstrate that electrodeposition of the cathode material is a simple, quick, and potentially scalable electrode synthesis method for producing high performing Zn‐ion electrodes without the use of binders or other additives.
Adaptation and validation of a scale of self‐efficacy and social support for physical activity in Spanish patients with severe mental disorders
Authors: Perez‐Cruzado David , Vera‐Garcia Elisa , Mayoral‐Cleries Fermin , Luciano Juan Vicente , Cuesta‐Vargas Antonio
Published: December 2019

Background

People with severe mental disorders (SMDs) suffer problems of obesity, a sedentary life, and poor physical condition, mainly due to low levels of physical activity. Self‐efficacy (SE) and social support (SS) are important components that influence participation in physical activity.

Methods

This study adapted a scale to assess SE and SS in promoting physical activity in Spanish people with SMDs, as well as provide preliminary evidence of its validity. One hundred Spanish patients (23% female) with SMDs, between 26 and 61 years old, completed the SE/SS assessment for SMD (SE/SS‐ASMD).

Results

The instrument seemed to capture a four‐factor structure in people with SMDs. Due to the lack of a gold standard, the scale was related to other instruments with which it might be expected to show a correlation, such as those for physical activity and its quality; however, the levels of correlation found were low (≈0.3). The Internal consistency (Cronbach's α) for the SE‐ASMD, SS‐ASMD staff, SS‐ASMD peers, and SS‐ASMD family scales were 0.76, 0.76, 0.80, and 0.80, respectively.

Conclusions

The psychometric analysis of the SE/SS‐ASMD supported its suitability as a new tool for researchers in the area of physical activity among people with SMDs.
Influence of multimedia and seating location in academic engagement and grade performance of students
Authors: Joshi Gyanendra Prasad , Jha Sudan , Cho Seongsoo , Seo Changho , Son Le Hoang , Thong Pham Huy
Published: December 2019

Many universities around the world use multimedia resources in large classrooms. The purpose of this study is to determine if there is any significant influence on student academic performance due to the use of multimedia (environment and tools) and seating location. This study analyses student data on grade performance and seating location for an undergraduate course at a multimedia classroom over eight semesters. This study also analyses whether short multimedia materials attract student attention in class using a computer vision experimental setup. It has been found that there is similar performance and distraction rate of students who sit at a similar proximity to the multimedia screen. The findings of this study are valuable for academic institutions and educators to design multimedia lectures and classrooms to enhance student performance.
Examining the impact of social commerce dimensions on customers' value cocreation: The mediating effect of social trust
Authors: Alalwan Ali Abdallah , Algharabat Raed Salah , Baabdullah Abdullah M. , Rana Nripendra P. , Raman Ramakrishnan , Dwivedi Rohita , Aljafari Abdullah
Published: December 2019

One of the main aspects of the Web 2.0 revolution has been social commerce that has resulted in many people across the world increasingly engaging with commercial activities over social media platforms. However, the academic and research interest in social commerce is still low, and more studies are required to accelerate awareness of the most important issues relating to social commerce, in particular, social trust and value cocreation. Thus, the present study aims to propose a conceptual model that is intended to enable greater understanding of the causal interactions between social commerce constructs, social trust, and customer value cocreation. We collected data using a sample of 300 followers and fans of online Facebook communities, and we analysed them by using a structural equation model. The results show that social commerce constructs positively impact on social trust. Furthermore, we found that social trust positively impacts on the three dimensions of customer value cocreation. We found that social trust mediates the relationship between the social commerce and customer value cocreation dimensions. The paper presents a considerable theoretical contribution for being the first study that links social commerce constructs with social trust. The linkage between social commerce constructs, social trust, and customer value cocreation dimensions will also be beneficial for social media marketing strategists and managers.
The First Organosilver(III) Fluoride, [PPh4][(CF3)3AgF]
Authors: Joven‐Sancho Daniel , Baya Miguel , Martín Antonio , Orduna Jesús , Menjón Babil
Published: December 2019

Organosilver(III) fluoride complexes have been assigned a key role in different fluorination processes. To the best of our knowledge, however, none of them seem to have been isolated or even detected thus far. Here we report on the successful synthesis of the trifluoromethyl derivative [PPh4][(CF3)3AgF], which has been isolated in high yield. The thermodynamic stability of the Ag−F bond is shown by calculation and demonstrated by multistage mass spectrometry (MSn) under collision‐induced dissociation (CID) conditions. Nevertheless, the substantial elongation found in the Ag−F bond (X‐ray) is correlated with a marked nucleophilic character of the terminal F ligand. This Ag−F bond is, in fact, quite reactive: it suffers hydrolysis and is also solvolyzed by thiols.
Cycloaddition of Dialkylalumanyl Anion toward Unsaturated Hydrocarbons in (1+2) and (1+4) Modes
Authors: Sugita Kengo , Nakano Ryo , Yamashita Makoto
Published: December 2019

The reactivity of dialkylalumanyl anion (1) towards naphthalene, anthracene, diphenylacetylene, and (E)/(Z)‐stilbenes was investigated. The compound 1reacts with naphthalene and anthracene through (1+4) cyclization, giving Al‐containing norbornadiene derivatives. In the reaction of1with diphenylacetylene and (E)/(Z)‐stilbenes, (1+2) cyclization proceeded to form Al‐C‐C three‐membered rings. Cyclization toward (E)‐ or (Z)‐stilbenes solely gave atrans‐cycloadduct. DFT calculations revealed that the cycloaddition of1with (Z)‐stilbene proceeds via a single transition state with a carbanion character, which results in the selectivity towards thetrans‐cycloadduct.
Noninvasive follicular neoplasm with papillary like nuclear features: A comprehensive analysis with a diagnostic algorithm
Authors: Rana Chanchal , Manjunath Shreyamsa , Ramakant Pooja , Singh Kulranjan , Babu Suresh , Mishra Anand
Published: December 2019

Background

Noninvasive follicular thyroid neoplasm with papillary‐like nuclear features (NIFTP) lacks the carcinoma label, avoiding aggressive therapy, physiological, social and financial impact of cancer diagnosis. Unfortunately, the preoperative diagnosis is still a challenge. Varied incidence of NIFTP has been document with limited data on preoperative cytological, radiological characteristics and the impact on risk of malignancy in each category of the Bethesda system of reporting thyroid cytopathology.

Method

Retrospective analysis of 20 NIFTPs with an attempt to provide a preoperative diagnostic algorithm based on the cytological and ultrasound features along with incidence and implication on risk of malignancy in various Bethesda categories with its impact on patient management.

Result

Incidence of NIFTP in our study was higher in comparison to that documented from other Asian countries. TIRADS 3 was the most common sonographic diagnosis. NIFTP was commonly preceded by indeterminate or benign Bethesda category. Major impact of excluding NIFTP form malignant category was seen on Bethesda categories II and IV with 20% and 27% reduction in risk of malignancy, respectively.

Conclusion

Retrospective analysis should not be confined only to follicular variant of papillary thyroid carcinoma but cases of follicular adenoma and adenomatous colloid nodule should always be included in review to ascertain the true incidence of NIFTP. NIFTPs are less likely to have malignant preoperative cytology. NIFTP shares major cytological and ultrasound features with follicular adenoma, adenomatous colloid nodule and minimally invasive follicular papillary carcinoma. When analyzed together, taking minor findings in consideration, can favor a diagnosis.
Auditory frequency discrimination in developmental dyslexia: A meta‐analysis
Authors: Witton Caroline , Swoboda Katy , Shapiro Laura R. , Talcott Joel B.
Published: December 2019

Auditory frequency discrimination has been used as an index of sensory processing in developmental language disorders such as dyslexia, where group differences have often been interpreted as evidence for a basic deficit in auditory processing that underpins and constrains individual variability in the development of phonological skills. Here, we conducted a meta‐analysis to evaluate the cumulative evidence for group differences in frequency discrimination and to explore the impact of some potential moderator variables that could contribute to variability in effect‐size estimations across studies. Our analyses revealed mean effect sizes for group differences on frequency discrimination tasks on the order of three‐quarters of a standard deviation, but in the presence of substantial inter‐study variability in their magnitude. Moderator variable analyses indicated that factors related both to participant variability on behavioural and cognitive variables associated with the dyslexia phenotype, and to variability in the task design, contributed to differences in the magnitude of effect size across studies. The apparently complex pattern of results was compounded by the lack of concurrent, standardised metrics of cognitive and reading component skills across the constituent studies. Differences on sensory processing tasks are often reported in studies of developmental disorders, but these need to be more carefully interpreted in the context of non‐sensory factors, which may explain significant inter‐ and intra‐group variance in the dependent measure of interest.
Grazing effects on intraspecific trait variability vary with changing precipitation patterns in Mongolian rangelands
Authors: Lang Birgit , Ahlborn Julian , Oyunbileg Munkhzuul , Geiger Anna , von Wehrden Henrik , Wesche Karsten , Oyuntsetseg Batlai , Römermann Christine
Published: December 2019

Functional traits are proxies for plant physiology and performance, which do not only differ between species but also within species. In this work, we hypothesized that (a) with increasing precipitation, the percentage of focal species which significantly respond to changes in grazing intensity increases, while under dry conditions, climate‐induced stress is so high that plant species hardly respond to any changes in grazing intensity and that (b) the magnitude with which species change their trait values in response to grazing, reflected by coefficients of variation (CVs), increases with increasing precipitation. Chosen plant traits were canopy height, plant width, specific leaf area (SLA), chlorophyll fluorescence, performance index, stomatal pore area index (SPI), and individual aboveground biomass of 15 species along a precipitation gradient with different grazing intensities in Mongolian rangelands. We used linear models for each trait to assess whether the percentage of species that respond to grazing changes along the precipitation gradient. To test the second hypothesis, we assessed the magnitude of intraspecific trait variability (ITV) response to grazing, per species, trait, and precipitation level by calculating CVs across the different grazing intensities. ITV was most prominent for SLA and SPI under highest precipitation, confirming our first hypothesis. Accordingly, CVs of canopy height, SPI, and SLA increased with increasing precipitation, partly confirming our second hypothesis. CVs of the species over all traits increased with increasing precipitation only for three species. This study shows that it remains challenging to predict how plant performance will shift under changing environmental conditions based on their traits alone. In this context, the implications for the use of community‐weighted mean trait values are discussed, as not only species abundances change in response to changing environmental conditions, but also values of traits considerably change. Including this aspect in further studies will improve our understanding of processes acting within and among communities.
Quality of chronic pain interventional treatment guidelines from pain societies: Assessment with the AGREE II instrument
Authors: Hoydonckx Yasmine , Kumar Pranab , Flamer David , Costanzi Matteo , Raja Srinivasa N. , Peng Philip , Bhatia Anuj
Published: December 2019

Background and Objective

Procedures to relieve pain are performed frequently but there are concerns about patient selection, appropriate image guidance, frequency and training for physicians. Patients, healthcare providers, policymakers and licensing bodies seek evidence‐based recommendations to use these interventions judiciously. In this review we appraised the methodological quality of recent clinical practice guidelines (CPGs) for interventional pain procedures.

Database and Data Treatment

A systematic search of the medical literature was performed. Three trained appraisers independently evaluated the methodological quality of the CPGs using a validated instrument, the Appraisal of Guidelines in Research and Evaluation II (AGREE II). Six domains were considered: 1) score and purpose; 2) stakeholder involvement; 3) rigour of development; 4) clarity of presentation; 5) applicability and 6) editorial independence. A total of 23 items were scored. CPGs were deemed ‘high quality’ if a mean scaled score above 60% for rigour of development and for two other domains was obtained.

Results

Mean scaled domain quality scores ranged from 61.72% to 69.99%. Despite being based on modest levels of evidence, two of the four included CPGs were considered to be of high methodological quality. The AGREE II scores across the four guidelines exhibited good inter‐rater reliability. None of the guidelines involved key stakeholders such as patients, other healthcare providers, and payers.

Conclusions

All four CPGs were limited by a weak execution of the guideline development process. There is a need to develop methodologically sound evidence‐based guidelines for the use of interventional pain procedures using a rigorous process that involves all relevant stakeholders.

Significance

This systematic review appraises the methodological quality of existing CPGs on interventional procedures using a validated epidemiological tool (AGREE II). The aims of this review were to identify methodological and knowledge gaps in existing CPGs. Findings of this study will help in development of a high‐quality CPG that can assist healthcare providers and patients in making informed decisions while ensuring that the right intervention is performed for the right patient at the right time. The quality of the evidence provided by the CPGs provided in support of their recommendations was also evaluated.
Bayesian estimation and model selection of a multivariate smooth transition autoregressive model
Authors: Livingston Jr Glen , Nur Darfiana
Published: December 2019

The multivariate smooth transition autoregressive model with order k (M‐STAR)(k) is a nonlinear multivariate time series model able to capture regime changes in the conditional mean. The main aim of this paper is to develop a Bayesian estimation scheme for the M‐STAR(k) model that includes the coefficient parameter matrix, transition function parameters, covariance parameter matrix, and the model order k as parameters to estimate. To achieve this aim, the joint posterior distribution of the parameters for the M‐STAR(k) model is derived. The conditional posterior distributions are then shown, followed by the design of a posterior simulator using a combination of Markov chain Monte Carlo (MCMC) algorithms that includes the Metropolis‐Hastings, Gibbs sampler, and reversible jump MCMC algorithms. Following this, extensive simulation studies, as well as case studies, are detailed at the end.
Metal Bioavailability Models: Current Status, Lessons Learned, Considerations for Regulatory Use, and the Path Forward
Authors: Mebane Christopher A. , Chowdhury M. Jasim , De Schamphelaere Karel A.C. , Lofts Stephen , Paquin Paul R. , Santore Robert C. , Wood Chris M.
Published: December 2019

Since the early 2000s, biotic ligand models and related constructs have been a dominant paradigm for risk assessment of aqueous metals in the environment. We critically review 1) the evidence for the mechanistic approach underlying metal bioavailability models; 2) considerations for the use and refinement of bioavailability-based toxicity models; 3) considerations for the incorporation of metal bioavailability models into environmental quality standards; and 4) some consensus recommendations for developing or applying metal bioavailability models. We note that models developed to date have been particularly challenged to accurately incorporate pH effects because they are unique with multiple possible mechanisms. As such, we doubt it is ever appropriate to lump algae/plant and animal bioavailability models; however, it is often reasonable to lump bioavailability models for animals, although aquatic insects may be an exception. Other recommendations include that data generated for model development should consider equilibrium conditions in exposure designs, including food items in combined waterborne–dietary matched chronic exposures. Some potentially important toxicity-modifying factors are currently not represented in bioavailability models and have received insufficient attention in toxicity testing. Temperature is probably of foremost importance; phosphate is likely important in plant and algae models. Acclimation may result in predictions that err on the side of protection. Striking a balance between comprehensive, mechanistically sound models and simplified approaches is a challenge. If empirical bioavailability tools such as multiple-linear regression models and look-up tables are employed in criteria, they should always be informed qualitatively and quantitatively by mechanistic models. If bioavailability models are to be used in environmental regulation, ongoing support and availability for use of the models in the public domain are essential. Environ Toxicol Chem 2019;39:60–84. © 2019 SETAC
State of the Science on Metal Bioavailability Modeling: Introduction to the Outcome of a Society of Environmental Toxicology and Chemistry Technical Workshop
Authors: Schlekat Christian , Stubblefield William , Gallagher Kathryn
Published: December 2019

A Society of Environmental Toxicology and Chemistry technical workshop was held in December 2017 to critically evaluate the current state of the science of metal bioavailability modeling. The availability of mechanistic models such as the biotic ligand model and the rapid development of empirical models such as multiple linear regressions means that choices are available in terms of bioavailability normalization approaches that can be used in metal risk assessments and the development of risk-based protective values for aquatic life. A key goal of the workshop was to provide potential users of metal bioavailability models with the information required to make appropriate decisions when choosing among mechanistic and empirical models. Workshop participants focused on the state of the science of metal bioavailability modeling, mechanistic and empirical model frameworks, validation of bioavailability models, and application of bioavailability models in risk-based decision-making approaches. The output of this workshop provides the necessary scientific information to incorporate bioavailability normalization in regulations pertaining to metals in freshwater systems. Environ Toxicol Chem 2019;39:42–47. © 2019 SETAC
The effect of wheat germ on the chemical properties and fatty acids of white cheese during the storage time
Authors: Çetinkaya Asya , Öz Fatih
Published: December 2019

In the present study, it was aimed to support the white cheese structure produced from cow's milk by adding wheat germ and to determine the changes in fatty acids and chemical composition of this additive storage time. The samples were taken on the 1st, 15th, and 30th days of storage, and some chemical properties and fatty acids were analyzed. The use of wheat germ in the production of white cheese had a significant effect (p < .05) on the fat, protein, salt, total acidity (% l.a) and dry matter properties of the cheese. It was determined that the most common fatty acids in the cheese samples were palmitic, oleic, stearic, and myristic acids. Wheat germ is a significant source due to its high protein content. Therefore, it can be expressed as an auxiliary raw material for the development of nutritional and functional properties in cheese production.
Classification of buried soils, cultural, and colluvial deposits in the Viking town Hedeby
Authors: Khamnueva‐Wendt Svetlana , Mitusov Andrey V. , Wendt Jann , Bork Hans‐Rudolf
Published: December 2019

Objective classification of settlement deposits is a prerequisite for understanding human‐environment interactions at habitation sites. This paper presents a novel approach combining a relatively fine‐scale sampling strategy, a multimethod geoarchaeological investigation of cores and multivariate statistics to aid in the classification and interpretation of complex and intricately stratified archaeological deposits. Heterogeneous settlement deposits, buried soils, colluvial, fluvial, and fluvioglacial sediments from cores retrieved in the Viking settlement Hedeby were investigated using six cost‐effectively measurable geoecological parameters: loss on ignition at 550°C, magnetic susceptibility, contents of stones, artifacts, bones, and charcoal with wood. Principal component analysis allowed identifying variables that would sufficiently describe data and cluster analysis enabled the classification of the materials. As a result, 13 classes were distinguished with a detailed and reliable differentiation of materials of natural and cultural genesis. Based on spatial distribution patterns of the classes, hypotheses regarding land use in the adjacent areas were made: Waste disposal in the valley of Hedeby‐brook and metallurgic activities north of it. This approach is valuable for coring‐based research at settlements, in particular at tightly managed heritage sites, and for surveys to identify potential excavation sites, whereas the set of variables must be adjusted according to local conditions.