bluuebunny/crossref_metadata_2025_split huggingface dataset:
In‐Memory Realization of Eligibility Traces Based on Conductance Drift of Phase Change Memory for Energy‐Efficient Reinforcement Learning
Authors: Lu Yingming , Li Xi , Yan Bonan , Yan Longhao , Zhang Teng , Song Zhitang , Huang Ru , Yang Yuchao 
Published: November 2021

AbstractReinforcement learning (RL) has shown outstanding performance in handling complex tasks in recent years. Eligibility trace (ET), a fundamental and important mechanism in reinforcement learning, records critical states with attenuation and guides the update of policy, which plays a crucial role in accelerating the convergence of RL training. However, ET implementation on conventional digital computing hardware is energy hungry and restricted by the memory wall due to massive calculation of exponential decay functions. Here, in‐memory realization of ET for energy‐efficient reinforcement learning with outstanding performance in discrete‐ and continuous‐state RL tasks is demonstrated. For the first time, the inherent conductance drift of phase change memory is exploited as physical decay function to realize in‐memory eligibility trace, demonstrating excellent performance during RL training in various tasks. The spontaneous in‐memory decay computing and storage of policy in the same phase change memory give rise to significantly enhanced energy efficiency compared with traditional graphics processing unit platforms. This work therefore provides a holistic energy and hardware efficient method for both training and inference of reinforcement learning.
Contract farming and the adoption of sustainable farm practices: Empirical evidence from cashew farmers in Ghana
Authors: Dubbert Caroline , Abdulai Awudu , Mohammed Sadick 
Published: November 2021

AbstractContract farming has been shown to increase agricultural productivity and thus welfare of farmers in developing countries. However, studies that look at the potential environmental effects of contract farming remain quite scanty. This is however crucial, since contract farming may contribute to intensification in cultivation of the contracted crops, in terms of area and the intensity of inputs used. This study investigates the impact of participation in contract farming on sustainable farm practices, using a marginal treatment effects (MTEs) approach to account for potential selection bias and heterogeneity across households. The empirical results show significant heterogeneity in the effects of contract farming on the intensity of sustainable farm practice use. In particular, farmers with high propensity to participate in contract farming tend to have low probabilities of using sustainable farm practices. The findings of this study not only provide new insights into the heterogeneous effects of contract farming, but also entry points for further research to address the dual challenge of agriculture to produce sufficient food, while reducing the adverse impact on the environment.
Organic fertigation system in saline‐sodic soils: A new paradigm for the restoration of soil health
Authors: Kumar Chitranjan , Ramawat Naleeni , Verma Aditya Kumar 
Published: November 2021

AbstractA continuous decline in soil organic C (SOC) and an increase in salt‐affected areas are a challenge to future sustainability. We searched on the scientific databases of Web of Science, Scopus (Elsevier) database, and Google. We reviewed 101 studies of the last 25 yr with the following keywords: drip irrigation, fertigation system, liquid biochar, liquid organic, organic fertigation, saline‐sodic soils, and salinization. Our objectives were to identify knowledge gaps to direct future organic research and assess the effect of organic amendments on meeting the plant's N, P, and K requirements in saline‐sodic soils. The review showed that organic fertigation systems reduce salt concentration in irrigation water and inhibit glutamine synthetase by N‐fixing diazotrophs. The system increases photosynthetic activities in plants, microbial biomass C, bacterial colonization, plant–mycorrhizal association, and phospholipid‐derived fatty acids from microbes. It increases essential soil nutrients, including SOC; increases salt/water stress tolerance; and reduces Na+ ion toxicity in plants by regulating abscisic acid pathways in saline‐sodic soils. It creates a conducive environment for phosphatase, dehydrogenase, urease, protease, α‐amylase, and gibberellins. This review sketches the role of silicic acid, salicylic acid, and liquid organics in plant growth mechanisms: enhanced photosynthesis, increased salt/water tolerance, and reduced Na+ toxicity. It suggests novel strategies to develop a task force to promote a community–corporate farming system to adopt cost‐effective green technologies for bioresource regeneration, diverse market production, and social capital generation. We develop a synergy between organic fertigation system and community–corporate farming to bring much‐needed agricultural sustainability.
Additivity of the mechanical properties for acrylonitrile‐butadiene‐styrene resins
Authors: Zhang Huan , Ding Fang , Liu Tingli , Liu Lunyang , Li Yunqi 
Published: November 2021

AbstractAcrylonitrile‐butadiene‐styrene (ABS) resins have broad applications in automotive, transportation, and electronic industry attributed from their steadily tunable mechanical properties though varying compositions. It arises a question whether the additivity principle is applicable in their composition‐mechanical properties relationship. Here, we evaluated the applicability of the additivity principle for Young's modulus (YM), tensile strength (TS), and elongation at break (EB), based on a collection of 360 ABS resins from literatures and commercial products. We found that more than 90% of resins satisfy the additivity principle for YM and TS. While for EB, it varied from 14% to 100% depending on the combinations (A + B + S, AB + S, A + BS, or AS + B) and the contributed weights by mass, molar, or volume fractions. The majority of nonadditive resins have EB less than 20%, where the presence of the agglomeration of rubber phases, incompatible internal phases, cracks for those less ductile ABS resins are widely used qualitative and apparent reasons for the non‐predictable EB and the failure for the additivity principle. We then construct a classification model to distinguish the additive from nonadditive resins for EB, the area under the receiver operating characteristic curve (AUC) only achieves a fair value of 0.84. It further reveals that the fraction of acrylonitrile and butadiene, processing temperature, the length of spline, and the strain rate in the tensile test are important factors responsible for the failure of the additivity for EB. This study provides a quantitative reference to manipulate the mechanical properties for ABS resins beyond empirical evaluations.
Degeneracy in the nervous system: from neuronal excitability to neural coding
Authors: Kamaleddin Mohammad Amin 
Published: November 2021

AbstractDegeneracy is ubiquitous across biological systems where structurally different elements can yield a similar outcome. Degeneracy is of particular interest in neuroscience too. On the one hand, degeneracy confers robustness to the nervous system and facilitates evolvability: Different elements provide a backup plan for the system in response to any perturbation or disturbance. On the other, a difficulty in the treatment of some neurological disorders such as chronic pain is explained in light of different elements all of which contribute to the pathological behavior of the system. Under these circumstances, targeting a specific element is ineffective because other elements can compensate for this modulation. Understanding degeneracy in the physiological context explains its beneficial role in the robustness of neural circuits. Likewise, understanding degeneracy in the pathological context opens new avenues of discovery to find more effective therapies.
Synthesis and Antimicrobial Activity of Ursolic Acid Ester Derivatives
Authors: Pereira Vinicius Viana , Pereira Nara Rúbia , Pereira Rafael César Gonçalves , Duarte Lucienir Pains , Takahashi Jacqueline Aparecida , Silva Roqueline Rodrigues 
Published: November 2021

AbstractInfections caused by microorganisms are a major cause of morbidity and mortality worldwide, and natural products continue to be important sources for the discovery of new antimicrobial agents. Ursolic acid is a triterpene with known antibacterial action, being naturally found in plants, such as Jaracanda oxyphylla and Jacaranda caroba (Bignoniaceae). Ursolic acid derivative esters have revealed potential biological activities, such as antitumor, antiviral, and antibacterial activity. In this study, sixteen esters (1‐16) were synthesized from ursolic acid using DIC/DMAP and characterized by infrared (IR), nuclear magnetic resonance (1H‐ and 13C‐NMR) and mass spectrometry. All ursolic acid esters were evaluated against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and the yeast Candida albicans. Six compounds are herein described for the first time (3, 9, 11, 13, 14 and 16) with yields up to 91.6 %. Compounds 11 (3β‐(3,4‐dimethoxybenzoyl)ursolic acid) and 15 (3β‐nicotinoylursolic acid) displayed promising antifungal activity, with inhibition of C. albicans growth of 93.1 and 95.9 %, respectively.
Crown Ether Host‐Guest Molecular Ferroelectrics
Authors: Zhang Yun‐Fang , Di Fang‐Fang , Li Peng‐Fei , Xiong Ren‐Gen 
Published: November 2021

AbstractIn recent years, molecular ferroelectrics have received great attention due to their low weight, mechanical flexibility, easy preparation and excellent ferroelectric properties. Among them, crown‐ether‐based molecular ferroelectrics, which are typically composed of the host crown ethers, the guest cations anchored in the crown ethers, and the counterions, are of great interest because of the host‐guest structure. Such a structure allows the components to occur order‐disorder transition easily, which is beneficial for inducing ferroelectric phase transition. Herein, we summarized the research progress of crown ether host‐guest molecular ferroelectrics, focusing on their crystal structure, phase transition, ferroelectric‐related properties. In view of the small spontaneous polarization and uniaxial nature, we outlook the chemical design strategies for obtaining high‐performance crown‐ether‐based molecular ferroelectrics. This minireview will be of guiding significance for the future exploration of crown ether host‐guest molecular ferroelectrics.
A Series of Polyoxometalate‐Viologen Photochromic Materials for UV Probing, Amine Detecting and Inkless and Erasable Printing
Authors: Ying Jun , Jin Liang , Sun Chen‐Xi , Tian Ai‐Xiang , Wang Xiu‐Li 
Published: November 2021

AbstractIn this work, by using two kinds of viologen ligands three POM‐based Compounds were obtained under hydrothermal conditions, namely [AgI(bmypd)0.5(β‐Mo8O26)0.5] (1) (bmypd ⋅ 2Cl=1,1′‐[Biphenyl‐4,4′‐bis(methylene)]bis(4,4′‐bipyridyinium)dichloride), [AgI2(bypy)4(HSiW12O40)2] ⋅ 14H2O (2) and [AgI(bypy)(γ‐Mo8O26)0.5] (3) (bypy⋅Cl=1‐Benzyl‐4,4′‐bipyridyinium chloride). The structures were characterized by Fourier transform infrared spectroscopy (FT–IR), Powder X‐ray diffraction (PXRD), X‐ray photoelectron spectroscopy (XPS) and single crystal X‐ray diffraction. Compounds 1–3 show excellent photochromic ability with fast photoresponse under the irradiation of ultraviolet light with different degrees of color changes. So compounds 1–3 can be used as visible ultraviolet detectors. Compounds 1–3 also possess photoluminescence properties with fast and excellent fluorescence quenching effect. Compounds 1–3 also can be used as inkless and erasable printing materials with suspensions of 1–3 applied to filter paper. Compounds 1–3 can also produce color changes in amine vapor environment, especially in an NH3 atmosphere. Compounds 1–3 can be used as organic amine detectors.
Enantiomeric separation of racemic amlodipine by sequential fractional crystallization through formation of diastereomeric salt solvates and co‐crystals of solvate‐like compounds with specific structure — A tandem resolution
Authors: Bánhegyi Dorottya Fruzsina , Szolcsányi Dóra , Madarász János , Pálovics Emese 
Published: November 2021

AbstractA new resolution method of racemic amlodipine has been developed. The racemic compound is reacted in a suitable solvent with 0.25‐mol equivalent of (R,R)‐tartaric acid. After the decomposition of the diastereomeric salt, the remaining racemic fraction is precipitated with half‐equivalent of fumaric acid, and the pure amlodipine enantiomer is obtained. A quarter equivalent of the same resolving agent, (R,R)‐tartaric acid has been also added to the mother liquor to obtain the other enantiomer. The advantage of this method is that both of the enantiomers of amlodipine could be obtained with high enantiomeric excess with the same resolving agent. The racemic excess can also be isolated and re‐resolved. Achiral reagents (urea and thiourea) have been added to the resolving agent. These neutral additives are incorporated as co‐crystals in the structure of the diastereomeric salts. The used solvate‐former solvents and achiral additives are structurally similar, and their presence can enable the fractional separation of the diastereomers. In addition, the racemate, the enantiomers, and some intermediate salts with high diastereomeric excess obtained in the resolution process of amlodipine have been also subjected to thermal (DSC, TG/DTA‐EGA‐MS, and ‐FTIR), analytical (FTIR spectroscopic), and structural (XRD) comparisons, which indicate that the key‐intermediate crystalline diastereomeric salts—as solvates and co‐crystals—inherit a kind of structural similarity from their related additives—solvents (DMF, DMAA, and DMSO) or (thio)ureas, respectively.
Efficient preparation of stereopure amphiphilic 1,2‐amino alcohols by using preparative enantioselective HPLC
Authors: Kanai Hayato , Yamada Kuniyo , Kodama Koichi , Ishida Yasuhiro 
Published: November 2021

AbstractChiral amphiphiles are useful for controlling the structures and properties of supramolecular assemblies, but their stereocontrolled synthesis is generally difficult, because their long alkyl chains tend to bring unfavorable effects on the solubility, reactivity, and crystallinity of molecules. Typical examples are amphiphilic 1,2‐amino alcohols (S)‐1 and (1S,2S)‐2 developed by our group, which were known to serve as chiral reaction media for controlling the stereochemistry of asymmetric photoreactions. We previously developed synthetic schemes for these 1,2‐amino alcohols, but their synthetic efficiencies were unsatisfactory (13 steps with 2% overall yield for (S)‐1; eight steps with 8% yield for (1S,2S)‐2). As the main reason of such low efficiencies, the stereocontrolling methods we previously employed (diastereomer‐salt crystallization for (S)‐1; stereoselective reactions for (1S,2S)‐2) were not ideal. Here, we report highly improved synthetic schemes for (S)‐1 and (1S,2S)‐2 based on the enantioselective high performance liquid chromatography (HPLC) separation of intermediates in preparative scales. Compared with the previous schemes, the new schemes are advantageous in fewer number of steps, higher overall yield, and lower risk of racemization (seven steps with 15% overall yield for (S)‐1; seven steps with 26% overall yield for (1S,2S)‐2).
The Photoinduced Electrocyclization Reaction of Triphenylamine (TPA) in Sustainable and Confined Micellar Solutions: A Steady‐State and Laser Flash Photolysis Approach
Authors: Sanmartín Rocío A. , Salum María L. , Protti Stefano , Mella Mariella , Bonesi Sergio M. 
Published: November 2021

AbstractThe irradiation of triphenylamine (TPA) under homogeneous (cyclohexane, acetonitrile and methanol) and micellar [sodium dodecyl sulfate (SDS), cetyltrimethylammonium chloride (CTAC) and polyethylene glycol monododecyl ether (Brij‐P35)] conditions has been investigated through a combined steady‐state and time‐resolved spectroscopic approach. Photolysis of TPA at 254 nm in different media afforded N‐phenylcarbazole (N−PhCA) as the main photoproduct, and when the photoreaction of TPA was carried out in micellar solution the relative rate of formation of N−PhCA was found to be faster than in homogeneous media due to the environmental confined and hydrophobic micellar core. On the other hand, the transient N‐phenyl‐4a,4b‐dihydrocarbazole (DHC0) was detected and fully characterized via laser flash photolysis. Finally, the location of TPA within the hydrophobic core of the micelle was investigated by 1D and 2D NMR spectroscopic analyses.
Identification of the designer steroid 17β‐hydroxy 5α‐androst‐1‐en‐3‐one cypionate in an injectable liquid
Authors: Griffin Kelsey M. , Lorenz Lisa M. , Flurer Rick A. 
Published: November 2021

AbstractIn the screening of an injectable liquid marketed for body building, a steroid resembling 1‐testosterone was found. The compound of interest was isolated using HPLC‐UV detection coupled to an analytical scale fraction collector and subsequently characterized using HRAM‐MS, NMR spectrometry, and GC‐MS. The designer steroid was identified as 17β‐hydroxy 5α‐androst‐1‐en‐3‐one cypionate, an analog of 1‐testosterone that had not been reported.
Carbon and nitrogen isotopic analysis of morphine from opium and heroin samples originating in the four major heroin producing regions
Authors: Thompson Robert A. , Morello David R. , Panicker Sini , Toske Steven G. , Li Li 
Published: November 2021

AbstractThe forensic analysis of stable isotopes is a valuable tool to geo‐source natural or semisynthetic drugs such as cocaine and heroin. The present study describes a novel methodology to isolate morphine from opium for isotopic analysis. Furthermore, this isotopic data from regional sources is corroborated with morphine data obtained from seized heroin (deacetylated to morphine) from the same regions. All five primary alkaloids of opium, namely, morphine, codeine, thebaine, noscapine, and papaverine, were quantified using high performance liquid chromatography with photodiode array (PDA) detector before the preparative experiment to gather a complete major alkaloidal profile. Morphine fractions of authentic opium submissions from Mexico, South America, Southwest Asia, and Southeast Asia were isolated and collected using preparative high performance liquid chromatography, and the collected morphine samples were subsequently analyzed by isotope ratio mass spectrometry. Carbon and nitrogen isotope data are presented. The data demonstrate that nitrogen ratios are capable of differentiating samples from Mexico and South America while carbon ratios are able to distinguish Southwest Asian samples from other source regions. Analogous results have routinely been observed (as part of Heroin Signature Program analysis) for morphine obtained from deacetylated authentic heroin samples from the same source regions. The results suggest that the poppy growing region has a greater influence on the carbon and nitrogen isotope values than the heroin manufacturing processes employed. When utilized in conjunction with existing signature methodologies, carbon and nitrogen isotope ratio data can enhance the ability to geo‐source heroin.
Trade‐off between flight capability and reproduction in Acridoidea (Insecta: Orthoptera)
Authors: Chang Huihui , Guo Xiaoqiang , Guo Shuli , Yang Nan , Huang Yuan 
Published: November 2021

AbstractIn many insect taxa, there is a well‐established trade‐off between flight capability and reproduction. The wing types of Acridoidea exhibit extremely variability from full length to complete loss in many groups, thus, provide a good model for studying the trade‐off between flight and reproduction. In this study, we completed the sampling of 63 Acridoidea species, measured the body length, wing length, body weight, flight muscle weight, testis and ovary weight, and the relative wing length (RWL), relative flight muscle weight (RFW), and gonadosomatic index (GSI) of different species were statistically analyzed. The results showed that there were significant differences in RWL, RFW, and GSI among Acridoidea species with different wing types. RFW of long‐winged species was significantly higher than that of short‐winged and wingless species (p < .01), while GSI of wingless species was higher than that of long‐winged and short‐winged species. The RWL and RFW had a strong positive correlation in species with different wing types (correlation coefficient r = .8344 for male and .7269 for female, and p < .05), while RFW was strong negatively correlated with GSI (r = −.2649 for male and −.5024 for female, and p < .05). For Acridoidea species with wing dimorphism, males with relatively long wings had higher RFW than that of females with relatively short wings, while females had higher GSI. Phylogenetic comparative analysis showed that RWL, RFW, and GSI all had phylogenetic signals and phylogenetic dependence. These results revealed that long‐winged individuals are flight capable at the expense of reproduction, while short‐winged and wingless individuals cannot fly, but has greater reproductive output. The results support the trade‐off between flight and reproduction in Acridoidea.
Functional diversity and habitat preferences of native grassland plants and ground‐dwelling invertebrates in private gardens along an urbanization gradient
Authors: Braschler Brigitte , Gilgado José D. , Rusterholz Hans‐Peter , Buchholz Sascha , Zwahlen Valerie , Baur Bruno 
Published: November 2021

AbstractUrbanization is occurring around the globe, changing environmental conditions and influencing biodiversity and ecosystem functions. Urban domestic gardens represent a small‐grained mosaic of diverse habitats for numerous species. The challenging conditions in urban gardens support species possessing certain traits, and exclude other species. Functional diversity is therefore often altered in urban gardens. By using a multi‐taxa approach focused on native grassland plants and ground‐dwelling invertebrates with overall low mobility (snails, slugs, spiders, millipedes, woodlice, ants, rove beetles), we examined the effects of urbanization (distance to city center, percentage of sealed area) and garden characteristics on functional dispersion, functional evenness, habitat preferences and body size. We conducted a field survey in 35 domestic gardens along a rural–urban gradient in Basel, Switzerland. The various groups showed different responses to urbanization. Functional dispersion of native grassland plants decreased with increasing distance to the city center, while functional dispersion of ants decreased with increasing percentage of sealed area. Functional evenness of ants increased with increasing distance to the city center and that of rove beetles decreased with increasing percentage of sealed area. Contrary to our expectation, in rove beetles, the proportion of generalists decreased with increasing percentage of sealed area in the surroundings, and the proportion of species preferring dry conditions increased with increasing distance to the city center. Body size of species increased with distance to city center for slugs, spiders, millipedes, ants, and rove beetles. Local garden characteristics had few effects on functional diversity and habitat preferences of the groups examined. Our study supports the importance of using multi‐taxa approaches when examining effects of environmental change on biodiversity. Considering only a single group may result in misleading findings for overall biodiversity. The ground‐dwelling invertebrates investigated may be affected in different ways from the more often‐studied flying pollinators or birds.