bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimum Conditions for Formation of Aflatoxin Mj-Trifiuoroacetic Acid Derivative
Authors: Stubblefield Robert D 
Published: February 2020

Abstract
Because thin-layer chromatographic (TLC) confirmation of identity and reverse-phase liquid chromatographic (LC) determination with fluorescence detection of aflatoxin M1 both require the derivative formed in the reaction of M1 and trifluoroacetic acid (TFA), various reaction conditions were studied to obtain complete derivative formation. Of the various organic solvents tested, the reaction between M1 and TFA proceeded best in the nonpolar solvents hexane and isooctane. Other parameters investigated were reaction temperature and time, aflatoxin M1 concentration, and solvent volume. The following procedure is considered optimum: 200 μL each of hexane and trifluoroacetic acid are mixed with M1 standard in a silylated glass vial or with milk residue in a regular glass vial with a Teflon-lined screw cap and heated 10 min at 40°C. The mixture is evaporated to dryness under N2, and the derivative is saved for TLC or LC. No unreacted aflatoxin M1 was detected by reverse-phase LC after this procedure was incorporated for analysis of milk samples.
Optimization of Chick Embryotoxicity Bioassay for Testing Toxicity Potential of Fungal Metabolites
Authors: Prelusky Dan B , Hamilton Robert M G , Foster Brian C , Trenholm Locksley H , Thompson Brian K 
Published: February 2020

Abstract
The optimization of a simple, sensitive procedure using a chick embryotoxicity screening test (CHEST) bioassay for detection of toxic compounds is presented. Dosing protocols of eggs, using several mycotoxins (aflatoxin B„ deoxynivalenol, T-2 toxin) and appropriate controls, were evaluated for embryonic sensitivity, overall practicality of the procedure, and consistency of results. It was found that both type of carrier solvent and volume injected could significantly affect overall embryonic mortality. The chick embryo was most sensitive to the effects of toxins and solvents after 1 or 2 days of incubation; a rapid decrease in response was observed as the age of the embryo at dosing increased. Following administration of the toxins just below the shell membrane by way of a small hole (&lt;0.5 mm diameter) punched in the shell, a good dose-response (°/o mortality) could be obtained regardless of the site of injection (except directly into the yolk), although dosing via the air sac position resulted in a slightly better statistical outcome. Although some variations in calculated LD50 values were found among repeated assays, statistical analyses showed that the differences were not due to dosing protocol but to the variations in embryo sensitivities among batches of eggs. Thus, if standard reference toxins for comparison are run concurrently, the CHEST assay can prove to be a very satisfactory model, as well as having considerable flexibility to be adapted to the needs and resources of many laboratories.
Fecal bacterial community of finishing beef steers fed ruminally protected and non-protected active dried yeast
Authors: Ran Tao , Jiao Peixin , AlZahal Ousama , Xie Xiaolai , Beauchemin Karen A , Niu Dongyan , Yang Wenzhu 
Published: February 2020

Abstract
Our previous study suggested that supplementation of high-grain diets with ruminally protected and non-protected active dried yeast (ADY) may potentially reduce manure pathogen excretion by feedlot cattle. We hypothesized that feeding ruminally protected ADY might change the fecal bacterial community of finishing cattle. The objective of this study was to investigate the effects of feeding ruminally protected and non-protected ADY to finishing beef steers on their fecal bacterial community. Fresh fecal samples were collected on day 56 from 50 steers fed one of five treatments: 1) control (no monensin, tylosin, or ADY), 2) antibiotics (ANT, 330 mg monensin + 110 mg tylosin·steer−1d−1), 3) ADY (1.5 g·steer−1d−1), 4) encapsulated ADY (EDY; 3 g·steer−1d−1), and 5) a mixture of ADY and EDY (MDY; 1.5 g ADY + 3 g EDY·steer−1d−1). Bacterial DNA was extracted from fecal samples and sequenced using a MiSeq high-throughput sequencing platform. A total number of 2,128,772 high-quality V4 16S rRNA sequences from 50 fecal samples were analyzed, and 1,424 operational taxonomic units (OTU) were detected based on 97% nucleotide sequence identity among reads, with 769 OTU shared across the five treatments. Alpha diversity indices, including species observed, Chao estimate, abundance-based coverage estimator, Shannon, Simpson, and coverage, did not differ among treatments, and principal coordinate analysis revealed a high similarity among treatments without independent distribution. Bacteroidetes and Firmicutes were dominant phyla in the fecal bacterial community for all treatments, with a tendency (P &lt; 0.10) for greater relative abundance of Bacteroidetes but lesser Firmicutes with ANT, EDY, and MDY compared with control steers. Prevotella was the dominant genus in all treatments and steers supplemented with ANT, EDY, and MDY had greater (P &lt; 0.05) relative abundance of Prevotella than control steers, but lesser (P &lt; 0.03) relative abundance of Oscillospira. No differences between ADY and control were observed for the aforementioned variables. Fecal starch contents were not different among treatments, but the relative abundance of Bacteroidetes, as well as Prevotella at genera level, tended (P &lt; 0.06) to be positively correlated to fecal starch content. We conclude that supplementing ruminally protected or non-protected ADY or ANT had no effect on diversity and richness of fecal bacteria of finishing beef cattle, whereas feeding protected ADY or ANT to finishing beef steers altered the dominant fecal bacteria at phylum and genus levels. Therefore, supplementation of ruminally protected ADY may potentially improve intestinal health by stimulating the relative abundance of Prevotella.
Characterization of a caffeoyl-CoA O-methyltransferase-like enzyme involved in biosynthesis of polymethoxylated flavones in Citrus reticulata
Authors: Liu Xiaojuan , Zhao Chenning , Gong Qin , Wang Yue , Cao Jinping , Li Xian , Grierson Donald , Sun Chongde 
Published: February 2020

Abstract
Polymethoxylated flavones (PMFs), which accumulate exclusively in fruit peel of citrus, play important physiological and pharmacological roles but the genetic basis for the methylation of flavonoids has not been fully elucidated in citrus. Here we characterize a caffeoyl-CoA O-methyltransferase-like enzyme, designated CrOMT1. The expression pattern of CrOMT1 was highly correlated with the concentration of the three major PMFs in two different citrus fruit tissues during fruit maturation. Exposure of fruit to UV-B radiation sharply increased the level of CrOMT1 transcripts and also led to the accumulation of three PMFs. The potential role of CrOMT1 was studied by testing the catalytic activity of recombinant CrOMT1 with numerous possible substrates in vitro. The enzyme could most efficiently methylate flavones with neighboring hydroxy moieties, with high catalytic efficiencies found with 6-OH- and 8-OH-containing compounds, preferences that correspond precisely with the essential methylation sites involved in the synthesis of the three naturally occurring PMFs in Citrus reticulata. This indicates that CrOMT1 is capable of in vitro methylation reactions required to synthesize PMFs in vivo. Furthermore, transient overexpression of CrOMT1 increased levels of the three major PMFs in fruit, indicating that CrOMT1 is likely to play an essential role in the biosynthesis of PMFs in citrus.
The Structure of Bias
Authors: Johnson Gabbrielle M 
Published: February 2020

Abstract
What is a bias? Standard philosophical views of both implicit and explicit bias focus this question on the representations one harbours, for example, stereotypes or implicit attitudes, rather than the ways in which those representations (or other mental states) are manipulated. I call this approach representationalism. In this paper, I argue that representationalism taken as a general theory of psychological social bias is a mistake, because it conceptualizes bias in ways that do not fully capture the phenomenon. Crucially, this view fails to capture a heretofore neglected possibility of bias, one that influences an individual’s beliefs about or actions toward others, but is, nevertheless, nowhere represented in that individual’s cognitive repertoire. In place of representationalism, I develop a functional account of psychological social bias which characterizes it as a mental entity that takes propositional mental states as inputs and returns propositional mental states as outputs in a way that instantiates social-kind inductions. This functional characterization leaves open which mental states and processes bridge the gap between the inputs and outputs, ultimately highlighting the diversity of candidates that can serve this role.
From Essence to Necessity via Identity
Authors: Leech Jessica 
Published: February 2020

AbstractAn essentialist theory of modality claims that the source of possibility and necessity lies in essence, where essence is (obviously) then not to be defined in terms of necessity. Hence such theories owe us an account of why it is that the essences of things give rise to necessities in the way required. A new approach to understanding essence in terms of the notion of generalized identity promises to answer this challenge by appeal to the necessity of identity. I explore the prospects for this approach, and argue that it fails. If one favours an account of essence in terms of generalized identity, then one will not, I argue, be able to satisfactorily defend an essentialist theory of modality against the challenge; if one wishes to defend an essentialist theory of modality, and thereby to give an explanation of how necessity arises from essence, one should not understand essence in terms of generalized identity.
LECX: a cubesat experiment to detect and localize cosmic explosions in hard X-rays
Authors: Braga J , Durão O S C , Castro M , D’Amico F , Stecchini P E , Amirábile S , Gonzalez Blanco F , Strauss C , Silva W , Schad V R , Reitano L A 
Published: February 2020

ABSTRACT
With the advent of the nanosat/cubesat revolution, new opportunities have appeared to develop and launch small (∼1000 cm3), low-cost (∼US$ 1M) experiments in space in very short time frames (∼2  yr). In the field of high-energy astrophysics, in particular, it is a considerable challenge to design instruments with compelling science and competitive capabilities that can fit in very small satellite buses, such as a cubesat platform, and operate them with very limited resources. Here, we describe a hard X-ray (30–200 keV) experiment, LECX (‘Localizador de Explosões Cósmicas de Raios X’ – Locator of X-Ray Cosmic Explosions), that is capable of detecting and localizing within a few degrees events like gamma-ray bursts and other explosive phenomena in a 2U-cubesat platform, at a rate of ∼5 events per year. In the current gravitational wave era of astronomy, a constellation or swarm of small spacecraft carrying instruments such as LECX can be a very cost-effective way to search for electromagnetic counterparts of gravitational wave events produced by the coalescence of compact objects.
Unprecedented and highly stable lithium storage capacity of (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture for high-performance Li-ion batteries
Authors: Yu Wen-Bei , Hu Zhi-Yi , Jin Jun , Yi Min , Yan Min , Li Yu , Wang Hong-En , Gao Huan-Xin , Mai Li-Qiang , Hasan Tawfique , Xu Bai-Xiang , Peng Dong-Liang , Van Tendeloo Gustaaf , Su Bao-Lian 
Published: February 2020

Abstract
Active crystal facets can generate special properties for various applications. Herein, we report a (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture with unprecedented and highly stable lithium storage performance. Density functional theory calculations show that the (001) faceted TiO2 nanosheets enable enhanced reaction kinetics by reinforcing their contact with the electrolyte and shortening the path length of Li+ diffusion and insertion-extraction. The reduced graphene oxide (rGO) nanosheets in this TiO2/rGO hybrid largely improve charge transport, while the porous hierarchy at different length scales favors continuous electrolyte permeation and accommodates volume change. This hierarchically porous TiO2/rGO hybrid anode material demonstrates an excellent reversible capacity of 250 mAh g–1 at 1 C (1 C = 335 mA g–1) at a voltage window of 1.0–3.0 V. Even after 1000 cycles at 5 C and 500 cycles at 10 C, the anode retains exceptional and stable capacities of 176 and 160 mAh g–1, respectively. Moreover, the formed Li2Ti2O4 nanodots facilitate reversed Li+ insertion-extraction during the cycling process. The above results indicate the best performance of TiO2-based materials as anodes for lithium-ion batteries reported in the literature.
A self-consistent leptonic–hadronic interpretation of the electromagnetic and neutrino emissions from blazar TXS 0506+056
Authors: Cao Gang , Yang Chuyuan , Yang Jianping , Wang Jiancheng 
Published: February 2020

Abstract
The potential association between the blazar TXS 0506+056 and the neutrino event IceCube-170922A provides a unique opportunity to study the possible physical connection between high-energy photons and neutrinos. We explore the correlated electromagnetic and neutrino emissions of blazar TXS 0506+056 by a self-consistent leptonic–hadronic model, taking into account particle stochastic acceleration and all relevant radiative processes self-consistently. The electromagnetic and neutrino spectra of blazar TXS 0506+056 are reproduced by the proton synchrotron and hybrid leptonic–hadronic models based on the proton–photon interactions. It is found that the hybrid leptonic–hadronic model can be used to better explain the observed X-ray and $\gamma$-ray spectra of blazar TXS 0506+056 than the proton synchrotron model. Moreover, the predicted neutrino spectrum of the hybrid leptonic–hadronic model is closer to the observed one compared to the proton synchrotron model. We suggest that the hybrid leptonic–hadronic model is more favored if the neutrino event IceCube-170922A is associated with the blazar TXS 0506+056.
Untangling the Value Premium with Labor Shares
Authors: Donangelo Andres 
Published: February 2020

Abstract
This paper quantifies the relative importance of labor-induced operating leverage at explaining the value premium. I extend a traditional variance decomposition methodology using labor shares to disentangle labor leverage from the value premium and from the value spread and from the variation in profitability levels and growth. My extended decomposition shows that labor leverage explains approximately 50% of the value premium, whereas profitability and growth-based mechanisms explain the other 50%. I propose a tractable production-based asset-pricing model that qualitatively and quantitatively explains this finding, as well as the relation between book-to-market ratios, discount rates, profitability, and future growth.
‘My Master and Friend’: Social Networks and Professional Identity in American Medicine, 1789–1815
Authors: Naramore Sarah E. 
Published: February 2020

Summary
Between 1789 and 1813, over 3,000 men received medical instruction in Philadelphia from physician and educator Benjamin Rush. Despite the fact that on average students remained for only 1.4 years of formal education, this cohort of American doctors formulated a national and professional identity grounded in shared experiences and fostered through interpersonal networks. This essay argues that a networked approach to studying early American doctors will provide more robust information about the development of a distinctive American medical profession in the nineteenth century. Using large data sets gleaned from manuscript sources this project uncovers patterns of migration and communication for otherwise invisible American medical men.
A Survey of Systematic Evidence Mapping Practice and the Case for Knowledge Graphs in Environmental Health and Toxicology
Authors: Wolffe Taylor A M , Vidler John , Halsall Crispin , Hunt Neil , Whaley Paul 
Published: February 2020

Abstract
Systematic evidence mapping offers a robust and transparent methodology for facilitating evidence-based approaches to decision-making in chemicals policy and wider environmental health (EH). Interest in the methodology is growing; however, its application in EH is still novel. To facilitate the production of effective systematic evidence maps for EH use cases, we survey the successful application of evidence mapping in other fields where the methodology is more established. Focusing on issues of “data storage technology,” “data integrity,” “data accessibility,” and “transparency,” we characterize current evidence mapping practice and critically review its potential value for EH contexts. We note that rigid, flat data tables and schema-first approaches dominate current mapping methods and highlight how this practice is ill-suited to the highly connected, heterogeneous, and complex nature of EH data. We propose this challenge is overcome by storing and structuring data as “knowledge graphs.” Knowledge graphs offer a flexible, schemaless, and scalable model for systematically mapping the EH literature. Associated technologies, such as ontologies, are well-suited to the long-term goals of systematic mapping methodology in promoting resource-efficient access to the wider EH evidence base. Several graph storage implementations are readily available, with a variety of proven use cases in other fields. Thus, developing and adapting systematic evidence mapping for EH should utilize these graph-based resources to ensure the production of scalable, interoperable, and robust maps to aid decision-making processes in chemicals policy and wider EH.
A stranger among us: the occurrence of Cantellius (Balnoidea: Pyrgomatidae) an epibiont of scleractinias in stylasterids (Hydrozoa)
Authors: Zweifler Adi , Simon-Blecher Noa , Pica Daniela , Chan Benny K K , Roth Jonathan , Achituv Yair 
Published: February 2020

Abstract
Barnacles that fit morphologically into the description of the pyrgomatid genus Cantellius were retrieved from hydrozoan Stylasteridae. The use of molecular markers also confirmed the assignment of these barnacles to the genus Cantellius. Hitherto, stylasterids have not been recorded as hosts of pyrgomatids. This finding conflicts with and refutes the statement that scleractinans (Hexacorallia) are obligatory hosts of pyrgomatids. These are the first unequivocal records of living pyrgomatids in stylasterids, thus documenting a new type of habitat for this group of barnacles. Further inspections of stylasterids will probably reveal more new host records and, possibly, new pyrgomatids.
Cryo-EM Structure of the 2019-nCoV Spike in the Prefusion Conformation
Authors: Wrapp Daniel , Wang Nianshuang , Corbett Kizzmekia S. , Goldsmith Jory A. , Hsieh Ching-Lin , Abiona Olubukola , Graham Barney S. , McLellan Jason S. 
Published: February 2020

AbstractThe outbreak of a novel betacoronavirus (2019-nCov) represents a pandemic threat that has been declared a public health emergency of international concern. The CoV spike (S) glycoprotein is a key target for urgently needed vaccines, therapeutic antibodies, and diagnostics. To facilitate medical countermeasure (MCM) development we determined a 3.5 Å-resolution cryo-EM structure of the 2019-nCoV S trimer in the prefusion conformation. The predominant state of the trimer has one of the three receptor-binding domains (RBDs) rotated up in a receptor-accessible conformation. We also show biophysical and structural evidence that the 2019-nCoV S binds ACE2 with higher affinity than SARS-CoV S. Additionally we tested several published SARS-CoV RBD-specific monoclonal antibodies and found that they do not have appreciable binding to nCoV-2019 S, suggesting antibody cross-reactivity may be limited between the two virus RBDs. The atomic-resolution structure of 2019-nCoV S should enable rapid development and evaluation of MCMs to address the ongoing public health crisis.
Glycation and Serum Albumin Infiltration Contribute to the Structural Degeneration of Bioprosthetic Heart Valves
Authors: Frasca Antonio , Xue Yingfei , Kossar Alexander P. , Keeney Samuel , Rock Christopher , Zakharchenko Andrey , Streeter Matthew , Gorman Robert C. , Grau Juan B. , George Isaac , Bavaria Joseph E. , Krieger Abba , Spiegel David A. , Levy Robert J. , Ferrari Giovanni 
Published: February 2020

AbstractBackgroundBioprosthetic heart valves (BHV) are widely used to treat heart valve disease but are fundamentally limited by structural valve degeneration (SVD). Non-calcific mechanisms of SVD entirely account for approximately 30% of SVD cases and contribute to calcific SVD but remain understudied. Glycation mechanisms have not been previously associated with SVD, despite being established as degenerative in collagenous native tissues.ObjectivesTo determine whether blood component infiltration-based glycation and concomitant human serum albumin (HSA) deposition contribute mechanistically to SVD.MethodsImmunohistochemistry (IHC) was used to identify advanced glycation end-products (AGEs) and serum albumin accumulation in 45 aortic valve BHV explanted due to SVD, glutaraldehyde-treated bovine pericardium (BP) incubatedin vitroin glyoxal and HSA, and rat subcutaneous BP implants. Structural impacts of glycation-related mechanisms were evaluated by second harmonic generation (SHG) collagen imaging. Hydrodynamic effects of valve glycation and concomitant HSA exposure were studied with an ISO-5840-compliant pulse duplicator system using surgical grade BHV.ResultsAll 45 clinical explants and in vitro-incubated BP demonstrated accumulated AGE and HSA compared to un-implanted, un-exposed BHV. SHG revealed instigation of collagen malalignment similar to that in SVD explants by glycation and HSA infiltration. Rat subdermal explants also showed AGE and serum albumin accumulation. Pulse duplication demonstrated significantly reduced orifice area and increased pressure gradient and peak fluid velocity following glyoxal and HSA incubations.ConclusionsGlycation and concomitant HSA infiltration occur in clinical BHV and contribute to structural and functional degeneration of leaflet tissue, thus representing novel, interacting mechanisms of BHV SVD.