bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cross‐linked poly(benzoxazole‐co‐siloxane) networks with high thermal stability and low dielectric constant based on a new ortho‐amide functional benzoxazine
Authors: Yang Rui , Hao Boran , Sun Lin , Zhang Kan 
Published: August 2020

AbstractIn this study, an amide functionalized bis‐benzoxazine (AI‐al) has been synthesized using allylamine, ortho‐amide functional bis‐phenol and paraformaldehyde as raw materials via Mannich condensation. This newly obtained benzoxazine has been used to react with polydimethylsiloxane (PDMS) through hydrosilylation to form poly(benzoxazine‐co‐amide‐co‐siloxane) (AI‐al‐PDMS) featuring siloxane, amide and benzoxazine as repeating units. The chemical structures of both oxazine ring‐containing monomer and copolymer are confirmed by NMR and FT‐IR spectroscopies. Besides, the thermally activated polymerization behaviors of AI‐al and AI‐al‐PDMS are investigated by DSC, and the subsequent conversion of benzoxazole formation is studied by in situ FT‐IR. Moreover, dynamic mechanical analysis and thermogravimetric analysis are used to determine the thermal properties of the cross‐linked polymers. The resulting cross‐linked poly(benzoxazole‐co‐siloxane) derived from AI‐al‐PDMS shows excellent thermal stability (no Tg can be observed before 400°C; Td5 of 393°C) and low dielectric constants (2.52–2.13 in the frequency range of 1 Hz to 1 MHz), evidencing its great potential applications in electronic packing, aerospace, and other high‐performance fields.
Movements, diving behaviour and diet of type‐C killer whales (Orcinus orca) in the Ross Sea, Antarctica
Authors: Lauriano Giancarlo , Pirotta Enrico , Joyce Trevor , Pitman Robert L. , Borrell Asunción , Panigada Simone 
Published: August 2020

Abstract

The fish‐eating, type‐C ecotype, killer whale is a top predator in the Ross Sea, Antarctica. Increasing knowledge of this animal's foraging habitats, diet and movement patterns is listed amongst the research priorities adopted under the framework of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).
To contribute to this goal, satellite transmitters were deployed on 10 type‐C killer whales and skin biopsies were obtained from seven individuals in Terra Nova Bay (Ross Sea) during austral summer (January–February) 2015. Hierarchical switching state–space models (hSSSM) were applied to Argos satellite tracking data to describe the movements of tagged whales, which were then paired with available diving data. Stable isotopes analyses were performed on the biopsy samples to describe the diet.
A total of 8,803 Argos locations were available to fit the hSSSM. All whales engaged in potential foraging activity in localized areas along the Ross Sea coastline, followed by uninterrupted travel (i.e. migration) outside Antarctic waters, with no evidence of foraging activity. The pattern of deeper dives matched the occurrence of encamped behaviour indicated by the hSSSM results. The stable isotopes analysis indicated that Antarctic toothfish comprised the largest component (35%) of the prey biomass, raising concerns since this species is targeted by commercial fishery in the Ross Sea Region.
These results provide new insights into the ecology of type‐C killer whales in the Ross Sea Region, underlining a potential threat from commercial fishing in the area. Considering the recent establishment of the Ross Sea Region Marine Protected Area, these findings will contribute to the required Research and Monitoring Programme of the Marine Protected Area and provide new empirical evidence to inform conservation measures in the existing Terra Nova Bay Antarctic Special Protected Area.
The antimalarial activity of indole alkaloids and hybrids
Authors: Li Jue‐Ying , Sun Xiao‐Feng , Li Jing‐Jing , Yu Fen , Zhang Yi , Huang Xiu‐Juan , Jiang Feng‐Xia 
Published: August 2020

AbstractMalaria, caused by the genus Plasmodium, remains a global public health concern. It is estimated by the World Health Organization that over 40% of the world's population lives in areas at risk for malarial transmission, and around half a million people succumb to this infectious disease annually, which is related to the rapid spread of drug‐resistant parasite strains. Indole derivatives, which possess broad‐spectrum pharmacological properties, play a crucial role in the discovery of new drugs. Many indole derivatives exhibited potential in vitro and in vivo activity against both drug‐sensitive and drug‐resistant malaria, suggesting that the indole moiety is a useful template for the development of novel antimalarial agents. This review outlines the advances in indole alkaloids and hybrids with antimalarial potential in the recent decade.
Cell death‐inducing properties of selected dendrimers against different breast cancer and leukemia cell lines
Authors: Baecker Daniel , Kapp Timo , Schumacher Petra , Gust Ronald , Kircher Brigitte 
Published: August 2020

AbstractDendrimers represent an opportunity for targeted drug delivery into tumor cells. This is facilitated, for example, by loading of dendrimers with anticancer compounds. However, to assess the effects caused by such conjugates, knowledge of the cytotoxicity of the dendrimers themselves is necessary. The poly(amido amine)‐derived dendrimers G1(Phe)6, G1(Dan)3, and G2 were selected due to their different numbers of free amino groups and the poly(propylene imine) (PPI) dendrimer PPI‐G3 served as a reference. The compounds were evaluated for cell‐death induction using breast cancer (MCF‐7, MDA‐MB‐231) and leukemia (LAMA‐84, K562, SD‐1, SUP‐B15) cell lines. The compounds exhibited concentration‐dependent effects in the low micromolar range against the mammary carcinoma cells. A dependency on the generation, and particularly on the type of dendrimer, was deduced while the quantity of the free amino groups was subsidiary. G2 revealed to be most cytotoxic, also against all tested leukemia cell lines. The cell line SD‐1, however, was susceptible to all dendrimers. The mode of cell death was mainly determined by necrosis, especially at higher concentrations, while apoptosis played a subordinate role. The other dendrimers exerted no antimetabolic effects against LAMA‐84, K562, and SUP‐B15 cells. Therefore, these dendrimers are generally suitable as nontoxic drug carriers for leukemia cells.
Role of Substituents at 3‐position of Thienylethynyl Spacer on Electronic Properties in Diruthenium(II) Organometallic Wire‐like Complexes
Authors: Roy Sourav Saha , Chowdhury Sabyasachi Roy , Mishra Sabyashachi , Patra Sanjib K. 
Published: August 2020

AbstractA series of organometallic complexes [Cl(dppe)2Ru−C≡C‐(3‐R−C4H2S)‐C≡C−Ru(dppe)2Cl] (3‐R‐C4H2S=3‐substituted thienyl moiety; R=−H, −C2H5, −C3H7, −C4H9, −C6H13, −OMe, −CN in5 a–5 grespectively) have been synthesized by systematic variation of 3‐substituents at the thienylethynyl bridging unit. The diruthenum(II) wire‐like complexes (5 a–5 g) have been achieved by the reaction of thienylethynyl bridging units, HC≡C‐(3‐R‐C4H2S)‐C≡CH (4 a–4 g) withcis‐[Ru(dppe)2Cl2]. The wire‐like diruthenium(II) complexes undergo two consecutive electrochemical oxidation processes in the potential range of 0.0 ‐ 0.8 V. Interestingly, the wave separation between the two redox waves is greatly influenced by the substituents at the 3‐position of the thienylethynyl. Thus, the substitution on 3‐position of the thienylethynyl bridging unit plays a pivotal role for tuning the electronic properties. To understand the electronic behavior, density functional theory (DFT) calculations of the selected diruthenium wire‐like complexes (5 a–5 e) with different alkyl appendages are performed. The theoretical data demonstrate that incorporation of alkyl groups to the thienylethynyl entity leaves unsymmetrical spin densities, thus affecting the electronic properties. The voltammetric features of the other two Ru(II) alkynyl complexes5 fand5 g(with −OMe and −CN group respectively) show an apparent dependence on the electronic properties. The electronic properties in the redox conjugate, (5 a+) with Kcof 3.9×106are further examined by UV‐Vis‐NIR and FTIR studies, showing optical responses in NIR region along with changes in “−Ru−C≡C−“ vibrational stretching frequency. The origin of the observed electronic transition has been assigned based on time‐dependent DFT (TDDFT) calculations.
Consistency in probability processing as a function of affective context and numeracy
Authors: Traczyk Jakub , Fulawka Kamil , Lenda Dominik , Zaleskiewicz Tomasz 
Published: August 2020

AbstractProcessing information about probabilities is an integral part of decision making under risk. Even when objective probabilities are explicitly provided, people tend to distort them, which is reflected by an inverted S‐shaped probability weighting function. Such distortions depend on different factors such as numeracy and affect. The present study contributes to the understanding of how people use probabilities in risky decision making by introducing the concept of consistency in probability processing―a measure of how coherent people are in using objective probabilities. We hypothesized that consistency would depend on factors similar to those that influence the shape of the probability weighting function. Moreover, we predicted that probability processing consistency would be related to better decision outcomes in an experimental betting task. In three experiments, participants were presented with the probability of a potential gain/loss and had to place a bet on a given chance to maximize their total earnings. We defined probability processing consistency as the variance of bets placed on the same probability value, with higher variance indicating lower consistency. We found that consistency in probability processing was lower in relatively affect‐rich conditions and greater for people with higher numeracy. Additionally, people who exhibited more consistent processing of probabilities gained higher earnings from the experimental task irrespective of whether their betting strategy was optimal and of their risk preference. Our findings imply that consistency in processing probabilities may be an important factor in understanding betting strategies and the quality of decisions.
Might SARS‐CoV‐2 Have Arisen via Serial Passage through an Animal Host or Cell Culture?
Authors: Sirotkin Karl , Sirotkin Dan 
Published: August 2020

AbstractDespite claims from prominent scientists that SARS‐CoV‐2 indubitably emerged naturally, the etiology of this novel coronavirus remains a pressing and open question: Without knowing the true nature of a disease, it is impossible for clinicians to appropriately shape their care, for policy‐makers to correctly gauge the nature and extent of the threat, and for the public to appropriately modify their behavior. Unless the intermediate host necessary for completing a natural zoonotic jump is identified, the dual‐use gain‐of‐function research practice of viral serial passage should be considered a viable route by which the novel coronavirus arose. The practice of serial passage mimics a natural zoonotic jump, and offers explanations for SARS‐CoV‐2's distinctive spike‐protein region and its unexpectedly high affinity for angiotensin converting enzyme (ACE2), as well as the notable polybasic furin cleavage site within it. Additional molecular clues raise further questions, all of which warrant full investigation into the novel coronavirus's origins and a re‐examination of the risks and rewards of dual‐use gain‐of‐function research.
Understanding the binding interaction between phenyl boronic acid P1 and sugars: determination of association and dissociation constants using S–V plots, steady‐state spectroscopic methods and molecular docking
Authors: Melavanki Raveendra , Sharma Kalpana , Yallur Basappa Chanabasapa , Kusanur Raviraj , Sadasivuni Kishor Kumar , Singh Diksha , Mane Smita , Katagi Kariyappa , Pattar Shridhar V. 
Published: August 2020

AbstractContinuous monitoring of glucose and sugar sensing plays a vital role in diabetes control. The drawbacks of the present enzyme‐based sugar sensors have encouraged the investigation into alternate approaches to design new sensors. The popularity of fluorescence sensors is due to their ability to bind reversibly to compounds containing diol. In this study we investigated the binding ability of phenyl boronic acid P1 for monosaccharides and disaccharides (sugars) in aqueous medium at physiological pH 7.4 using steady‐state fluorescence and absorbance. P1 fluorescence was quenched due to formation of esters with sugars. Absorbance and fluorescence measurements led to results that indicated that the sugars studied could be ordered in terms of their affinity to P1, as stated: sucrose > lactose > galactose > xylose > ribose > arabinose. In each case, the slope of modified Stern–Volmer plots was nearly 1, indicating the presence of only a single binding site in boronic acids for sugars. Docking studies were carried out using Schrodinger Maestro v.11.2 software. The binding affinity of phenyl boronic acid P1 with periplasmic protein (PDB ID 2IPM and 2IPL) was estimated using GlideScore.
Genome‐wide analysis of single nucleotide variants allows for robust and accurate assessment of clonal derivation in cell lines used to produce biologics
Authors: Kuhn Alexandre , Le Fourn Valérie , Fisch Igor , Mermod Nicolas 
Published: August 2020

AbstractA clonally derived (or “monoclonal”) cell line is a cell population derived from a single progenitor cell. Clonally derived cell lines are required for many biotechnological applications. For instance, recombinant mammalian cells used to produce therapeutic proteins are expected by regulatory authorities to be clonally derived. Assurance of clonal derivation (or “clonality”) is usually obtained from the characterization of the procedure used for cell cloning, for instance by assessing the success rate of single‐cell sorting but not by assessing the cell line itself. We have developed a method to assess clonal derivation directly from the genetic makeup of cells. The genomic test of clonality is based on whole‐genome sequencing and statistical analysis of single nucleotide variants. This approach quantifies the clonal fractions present in nonclonal samples and it provides a measure of the probability that a cell line is derived from a single cell. Upon experimental validation of the test, we show that it is highly accurate and that it can robustly detect minor clonal fractions of as little as 1% of the cell population. Moreover, we find that it is applicable to various cell line development protocols. This approach can simplify development protocols and shorten timelines while ensuring clonal derivation with high confidence.
Professional science education videos improve student performance in nonmajor and intermediate biology laboratory courses
Authors: Mutch‐Jones Karen , Sengupta Namrata , Minor V. Christine , Goudsouzian Lara K. 
Published: August 2020

AbstractUndergraduate biology laboratories emphasize hands‐on skills. Typically, descriptions of manual techniques are delivered via written instruction. Custom‐produced prelab instructional videos, which augment prelab instruction, have come into wider use in recent years. However, institutional and economic barriers can interfere with video production at all colleges and universities. In such cases, professionally produced laboratory instructional videos provide an attractive alternative. We hypothesized that students who watch short, professionally produced instructional videos before performing a laboratory would feel more confident and achieve greater learning gains than students whose prelab instruction was limited to handouts. For this proof of concept study, we investigated the value added when students watched a brief video, twice per lab, in an intermediate molecular biology course at a small, liberal arts university, and in a nonmajors biology course at a large, public research university. Both video and nonvideo comparison groups were administered a pre‐ and postlab exams. A postlab self‐efficacy survey was also administered to video groups. Our results reveal that in three out of the four laboratory classes, students who watched professional instruction videos performed significantly better in both pre‐ and postlab exams. For these students, we observed up to a two‐fold increase in test scores on scientific concepts and techniques. For all classes, most of the video group students reported that the video contributed to their confidence, comprehension of concepts, and understanding of how to conduct the lab. We conclude that professional instructional videos may address production barriers and have the potential to effectively enhance undergraduate science curricula and significantly improve students' performance.
Exploring the determinants of green bond issuance: Going beyond the long‐lasting debate on performance consequences
Authors: Russo Angeloantonio , Mariani Massimo , Caragnano Alessandra 
Published: August 2020

AbstractIn recent years, the need to create new financial tools to mobilize private capital and generate suitable resources to face both social and environmental challenges led to the development of new tools and ideas. In this context, green bonds have emerged as a new financial tool to better respond to sustainability themes. This study is the first attempt to explore in depth the determinants of green bond performance. We focused on three perspectives: the specific characteristics of projects financed through a green bond, the broader firm‐specific corporate sustainability‐oriented strategy of the firm, and a country‐level perspective analyzing the country‐specific determinants of green bond performance. To test the hypotheses a sample of 306 corporate green bonds issued by 85 companies and referring to 1,788 green projects between 2013 and 2016, were retrieved from the Bloomberg database. The results provide interesting theoretical and practical implications for green bond issuers as well as investors and governments interested in green bonds.
Advances and Opportunities in Epigenetic Chemical Biology
Authors: Beyer Jenna N. , Raniszewski Nicole R. , Burslem George M. 
Published: August 2020

AbstractThe study of epigenetics has greatly benefited from the development and application of various chemical biology approaches. In this review, we highlight the key targets for modulation and recent methods developed to enact such modulation. We discuss various chemical biology techniques to study DNA methylation and the post‐translational modification of histones as well as their effect on gene expression. Additionally, we address the wealth of protein synthesis approaches to yield histones and nucleosomes bearing epigenetic modifications. Throughout, we highlight targets that present opportunities for the chemical biology community, as well as exciting new approaches that will provide additional insight into the roles of epigenetic marks.
Genetic Incorporation of Selenotyrosine Significantly Improves Enzymatic Activity of Agrobacterium radiobacter Phosphotriesterase
Authors: An Xiaojing , Chen Chao , Wang Tianyuan , Huang Aiping , Zhang Dawei , Han Ming‐Jie , Wang Jiangyun 
Published: August 2020

AbstractTyrosine plays important roles in many enzymes. To facilitate enzyme design, mechanistic studies and minimize structural perturbation in the active site, here we report the genetic incorporation of a novel unnatural amino acid selenotyrosine (SeHF), which has single‐atom replacement in comparison to tyrosine. The arPTE‐(Agrobacterium radiobacter Phosphotriesterase) Tyr309SeHF mutant exhibits a significant 12‐fold increase in kcat and 3.2‐fold enhancement in kcat/KM at pH 7.0. Molecular dynamics simulations show that the SeHF309 mutation results in a conformational switch which opens up the product release pocket and increases the product release rate, thereby elevating the overall enzyme activity. Significant improvement of the catalytic efficiency at neutral pH by single unnatural amino acid (UAA) mutation broadens the application of this enzyme, and provides valuable insights to the mechanism. Our method represents a new approach for designing enzymes with enhanced activity.
Selenoimidazolium Salts as Supramolecular Reagents for Protein Alkylation
Authors: Lim David , Wen Xiaojin , Seebeck Florian P. 
Published: August 2020

AbstractSe‐benzyl selenoimidazolium salts are characterized by remarkable alkyl‐transfer potential under physiological conditions. Structure‐activity relationship studies show that selective monoalkylation of primary amines depends on supramolecular interactions between the selenoimidazole leaving group and the target nucleophile. We demonstrate that these reagents can be used for site‐selective and nearly quantitative modification of the model protein lysozyme on Lys13, bypassing the higher intrinsic reactivities of Lys1 and Lys33. These observations introduce selenoimidazolium salts as novel class of electrophiles for selective N‐alkylation of native proteins.
A review of glioblastoma tumors with primitive neuronal component and a case report of a patient with this uncommon tumor at a rare location
Authors: Shayganfar Azin , Ebrahimian Shadi , Mahzouni Parvin , Shirani Fattane , Aalinezhad Marzieh 
Published: August 2020

AbstractGlioblastoma with primitive neuronal component should be considered as a differential diagnosis of infratentorial tumors.
Three‐Dimensional Hierarchical Framework Loaded with Lithiophilic Nanorod Arrays for High‐Performance Lithium‐Metal Anodes
Authors: Qi Yanyuan , Lin Lin , Jian Zelang , Qin Kaiyan , Tan Yuxuan , Zou Yujie , Chen Wen , Li Fujun 
Published: August 2020

AbstractAlthough the highest theoretical specific capacity and lowest redox potential make lithium metal anodes essential for next‐generation high‐energy batteries, the infinite volume changes and uncontrollable Li dendrites severely restrict their application. Herein, the 3D hierarchical framework (3DHF) loaded with lithiophilic nanorod arrays on interwoven carbon fibers is constructed as a host to stabilize the Li metal anode. With cooperation of the lithiophilicity and the capillary force of the nanorod arrays, molten Li easily wraps the surface of the nanorods to form 3DHF−Li composite anodes. The void spaces and channels among the nanorods may provide a buffer space for Li stripping/plating to relieve the volume changes. In addition, the enlarged specific surface area reduces the local current density to homogenize Li deposition and suppress Li dendrites. The 3DHF−Li anodes exhibit improved cycle stability and rate capability in both symmetric cells and full cells, providing references for the development of Li composite anodes.
Comparison of Chemical and Interpretative Methods: the Carbon–Boron π‐Bond as a Test Case**
Authors: Gupta Radhika , Rezabal Elixabete , Hasrack Golshid , Frison Gilles 
Published: August 2020

AbstractQuantum chemical calculations and NBO, ETS‐NOCV, QTAIM and ELF interpretative approaches have been carried out on C‐donor ligand‐stabilized dihydrido borenium cations. Numerous descriptors of the C−B π‐bond strength obtained from orbital localization, energy partitioning or topological methods as well as from structural and chemical parameters have been calculated for 39 C‐donor ligands includingN‐heterocyclic carbenes and carbones. Comparison of the results allows the identification ofrelativeandabsolutedescriptors of the π interaction. For both families of descriptors excellent correlations are obtained. This enables the establishment of a π‐donation capability scale and shows that the interpretative methods, despite their conceptual differences, describe the same chemical properties. These results also reveal noticeable shortcomings in these popular methods, and some precautions that need to be taken to interpret their results adequately.