bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photohomolysis and Photoheterolysis in Aryl Sulfonates and Aryl Phosphates
Authors: Bonesi Sergio , Protti Stefano , Fagnoni Maurizio 
Published: January 2021

AbstractThe photochemical behaviour of selected aryl sulfonates and phosphates (ArOX) in polar and nonpolar media has been investigated by laser flash photolysis (LFP) experiments. Two main pathways have been identified, namely the photohomolysis of the ArO−X bond or the photoheterolysis of the Ar−OX bond depending on the nature of the leaving group (OX) and on the nature of the substituents on the aromatic ring. In nonpolar solvents the esters are quite photostable due to an efficient triplet deactivation. In polar solvents, the homolytic fragmentation of the ArO−S bond from the exited singlets was found in aryl sulfonates bearing moderately electron‐donating groups as well as electron‐withdrawing groups. In electron‐rich aryl phosphates and sulfonates photoheterolysis of the Ar−OP/Ar−OS bond took place as the exclusive pathway.
Intermolecular Hydroaminoalkylation of Alkynes
Authors: Kaper Tobias , Fischer Malte , Thye Hermann , Geik Dennis , Schmidtmann Marc , Beckhaus Ruediger , Doye Sven 
Published: January 2021

AbstractIntermolecular hydroaminoalkylation reactions of alkynes with secondary amines, which selectively give access to allylic amines with E configuration of the alkene unit, are achieved in the presence of titanium catalysts. Successful reactions of symmetrically substituted diaryl‐ and dialkylalkynes as well as a terminal alkyne take place with N‐benzylanilines, N‐alkylanilines, and N‐alkylbenzylamines.
Automated segmentation algorithm with deep learning framework for early detection of glaucoma
Authors: Natarajan Deepa , Sankaralingam Esakkirajan , Balraj Keerthiveena , Thangaraj Veerakumar 
Published: January 2021

AbstractEarly stage of diagnosis of eye diseases through automatic analysis in the retinal image is the emerging technology in the area of retinopathy. Glaucoma is the primary reason for the loss of visibility in people around the world. The separation of the disc and the cup in the optic region is the technique used to identify glaucoma in the human retinal image. In this paper, superpixel segmentation, followed by Modified Kernel Fuzzy C‐Means (MKFCM) algorithm is used to segment the optic disc and optic cup. The proposed segmentation method achieves a maximum average of F‐score as 0.979, an average boundary distance as 10.016 pixels, and an average correlation coefficient of 0.949. To train convolutional neural networks (CNN), the segmented images obtained by the MKFCM segmentation algorithm is given as the input for the identification of glaucoma. This CNN uses the gray level co‐occurrence matrix features calculated from the segmented image. The experiment used for this study demonstrates that CNN gives superior categorization correctness and requires fewer figures of knowledge iterations than the original CNN. The accuracy obtained by this proposed method is 94.2%. The model will help to identify the proper class of severity of glaucoma in retinal images.
An Androsterone‐H2@C60hybrid: Synthesis, Properties and Molecular Docking Simulations with SARS‐Cov‐2
Authors: Suárez Margarita , Makowski Kamil , Lemos Reinier , Almagro Luis , Rodríguez Hortensia , Herranz María Ángeles , Molero Dolores , Ortiz Orlando , Maroto Enrique , Albericio Fernando , Murata Yasujiro , Martín Nazario 
Published: January 2021

AbstractWe report the synthesis and characterization of a fullerene‐steroid hybrid that contains H2@C60and a dehydroepiandrosterone moiety synthesized by a cyclopropanation reaction with 76 % yield. Theoretical calculations at the DFT‐D3(BJ)/PBE 6‐311G(d,p) level predict the most stable conformation and that the saturation of a double bond is the main factor causing the upfield shielding of the signal appearing at −3.13 ppm, which corresponds to the H2located inside the fullerene cage. Relevant stereoelectronic parameters were also investigated and reinforce the idea that electronic interactions must be considered to develop studies on chemical‐biological interactions. A molecular docking simulation predicted that the binding energy values for the protease‐hybrid complexes were −9.9 kcal/mol and −13.5 kcal/mol for PLproand 3CLprorespectively, indicating the potential use of the synthesized steroid‐H2@C60as anti‐SARS‐Cov‐2 agent.
A Novel AKR1C3 Specific Prodrug TH3424 With Potent Antitumor Activity in Liver Cancer
Authors: He Ping , Wang Chunnian , Wang Yanlan , Wang Caiyan , Zhou Changhua , Cao Donglin , Li Jiang , Bushnell David A. , Li Qing , Kornberg Roger D. , Xie Wei , Wang Zhong 
Published: January 2021

Overexpression of AKR1C3, an aldo‐keto reductase, was recently discovered in liver cancers. In this study, an inverse correlation between AKR1C3 expression and survival of patients with liver cancer was observed. AKR1C3 inhibitors, however, failed to suppress liver cancer cell growth. The prodrug TH3424, which releases a DNA alkylating reagent upon reduction by AKR1C3, was developed to target tumors with overexpression of AKR1C3. TH3424 showed specific killing of liver cancer cells with AKR1C3 overexpression both in vitro and in vivo. In patient‐derived mouse xenograft models, TH3424 at doses as low as 1.5 mg/kg eliminated liver tumors with no apparent toxicity. Therefore, TH3424 is a promising drug candidate for liver cancer and other types of cancers overexpressing AKR1C3.
Interface Engineering of Needle‐Like P‐Doped MoS2/CoP Arrays as Highly Active and Durable Bifunctional Electrocatalyst for Overall Water Splitting
Authors: Hu Yan , Yu Hongbo , Qi Luoluo , Dong Jiaxin , Yan Puxuan , Taylor Isimjan Tayirjan , Yang Xiulin 
Published: January 2021

AbstractDeveloping a bifunctional water splitting catalyst with high efficiency and low cost are crucial in the electrolysis water industry. Here, we report a rational design and simple preparation method of MoS2‐based bifunctional electrocatalyst on carbon cloth (CC). The optimized P‐doped MoS2@CoP/CC catalyst presents low overpotentials for the hydrogen (HER) and oxygen evolution reactions (OER) of 64 and 282 mV in alkaline solution as well as 72 mV HER overpotential in H2SO4 at a current density of 10 mA cm−2. Furthermore, P‐MoS2@CoP/CC as a bifunctional catalyst delivered relatively low cell voltages of 1.83 and 1.97 V at high current densities of 500 and mA cm−2 in 30 % KOH. The two‐electrode system showed a remarkable stability for 30 h, even outperformed the benchmark RuO2||Pt/C catalyst. The excellent electrochemical performance can be credited to the unique microstructure, high surface area, and the synergy between metal species. This study presents a possible alternative for noble metal‐based catalysts to overcome the challenges of industrial applications.
Electron transfer in proton‐hydrogen collisions in dense semi‐classical hydrogen plasma
Authors: Das Kamalika , Das Biswajit , Rej Pramit , Ghoshal Arijit 
Published: January 2021

AbstractQuantum mechanical calculations have been accomplished to study the dynamics of the reaction: p + H(1s) → H(nlm) + p in dense semi‐classical hydrogen plasma. Interactions among the charged particles in plasma are represented by a pseudopotential which takes care of the collective effects at large distances and quantum effect of diffraction at small distances. Various capture cross sections are computed for the incident proton energy lying within 10 to 500 keV by applying a distorted wave method which uses a variationally determined closed‐form wave function of hydrogen atom. Moreover, an inclusive study is made to explore the effects of screening of plasma and quantum diffraction on various capture cross sections for a wide range of thermal Debye length and de Broglie wave length. It has been found that various cross sections suffer considerable changes due to varying Debye length and de Broglie wave length.
Not a cakewalk: Insights into movement of large carnivores in human‐dominated landscapes in India
Authors: Habib Bilal , Ghaskadbi Pallavi , Khan Shaheer , Hussain Zehidul , Nigam Parag 
Published: January 2021

AbstractLarge carnivores play an important role in the functioning of ecosystems, yet their conservation remains a massive challenge across the world. Owing to wide‐ranging habits, they encounter various anthropogenic pressures, affecting their movement in different landscape. Therefore, studying how large carnivores adapt their movement to dynamic landscape conditions is vital for management and conservation policy.A total of 26 individuals across 4 species of large carnivores of different sex and age classes (14 Panthera tigris, 3 Panthera pardus, 5 Cuon alpinus, and 4 Canis lupus pallipes) were GPS collared and monitored from 2014–19. We quantified movement parameters (step length and net squared displacement) of four large carnivores in and outside protected areas in India. We tested the effects of human pressures such as human density, road network, and landuse types on the movement of the species. We also examined the configuration of core areas as a strategy to subsist in a human‐dominated landscape using BBMM.Mean displacement of large carnivores varied from 99.35 m/hr for leopards to 637.7 m/hr for wolves. Tigers outside PAs exhibited higher displacement than tigers inside PAs. Moreover, displacement during day–night was significantly different for tigers inside and outside PAs. Similarly, wolf also showed significant difference between day‐night movement. However, no difference in day–night movement was found for leopard and dholes. Anthropogenic factors such as road length and proportion of agriculture within the home range of tigers outside PAs were found to be significantly different. All the habitat variables in the home range showed significant difference between the social canids. The core area size for tiger outside PA and wolf was found greater than PAs.The study on movement of large carnivore species across landscapes is crucial for conservation planning. Our findings can be a starting point for interlinking animal movement and landscape management of large carnivore conservation in the current Anthropocene.
Positive early‐late life‐history trait correlations in elephant seals
Authors: Oosthuizen W. Chris , Péron Guillaume , Pradel Roger , Bester Marthán N. , de Bruyn P. J. Nico 
Published: January 2021

AbstractCorrelations between early‐ and late‐life performance are a major prediction of life‐history theory. Negative early–late correlations can emerge because biological processes are optimized for early but not late life (e.g., rapid development may accelerate the onset of senescence; “developmental theory of aging”) or because allocation to early‐life performance comes at a cost in terms of late‐life performance (as in the disposable soma theory). But variation in genetic and environmental challenges that each individual has to cope with during early life may also lead to positive early–late life‐history trait correlations (the “fixed heterogeneity” or “individual quality” hypothesis). We analyzed individual life‐history trajectories of 7,420 known‐age female southern elephant seals (Mirounga leonina) monitored over 36 yr to determine how actuarial senescence (a proxy for late‐life performance) correlate with age at first reproduction (a proxy for early‐life performance). As some breeding events may not be detected in this field study, we used a custom “multievent” hierarchical model to estimate the age at first reproduction and correlate it to other life‐history traits. The probability of first reproduction was 0.34 at age 3, with most females breeding for the first time at age 4, and comparatively few at older ages. Females with an early age of first reproduction outperformed delayed breeders in all aspects we considered (survival, rate of senescence, net reproductive output) but one: early breeders appeared to have an onset of actuarial senescence 1 yr earlier compared to late breeders. Genetics and environmental conditions during early life likely explain the positive correlation between early‐ and late‐life performance. Our results provide the first evidence of actuarial senescence in female southern elephant seals.
Can we use a functional trait to construct a generalized model for ungulate populations?
Authors: Traill Lochran W. , Plard Floriane , Gaillard Jean‐Michel , Coulson Tim 
Published: January 2021

AbstractEcologists have long desired predictive models that allow inference on population dynamics, where detailed demographic data are unavailable. Integral projection models (IPMs) allow both demographic and phenotypic outcomes at the level of the population to be predicted from the distribution of a functional trait, like body mass. In species where body mass markedly influences demographic rates, as is the rule among mammals, then IPMs provide not only opportunity to assess the population responses to a given environment, but also improve our understanding of the complex interplay between traits and demographic outcomes. Here, we develop a body‐mass‐based approach to constructing generalized, predictive IPMs for species of ungulates covering a broad range of body size (25–400 kg). Despite our best efforts, we found that a reliable and general, functional, trait‐based model for ungulates was unattainable even after accounting for among‐species variation in both age at first reproduction and litter size. We attribute this to the diversity of reproductive tactics among similar‐sized species of ungulates, and to the interplay between density‐dependent and environmental factors that shape demographic parameters independent of mass at the local scale. These processes thus drive population dynamics and cannot be ignored. Environmental context generally matters in population ecology, and our study shows this may be the case for functional traits in vertebrate populations.
Seismic evaluation of reinforced concrete bridges using capacity‐based inelastic displacement spectra
Authors: Wang Ping‐Hsiung , Chang Kuo‐Chun , Dzeng Dzong‐Chwang , Lin Tzu‐Kang , Hung Hsiao‐Hui , Cheng Wei‐Chung 
Published: January 2021

AbstractA simplified seismic evaluation method using capacity‐based inelastic displacement spectra is proposed for reinforced concrete (RC) bridges. The proposed method can not only estimate the maximum displacements of bridges, but can also discriminate the damage indices between the bridge columns, where the Park and Ang's damage index () is considered a promising performance indicator due to its good relationship with the strength capacity state and actual visual damage condition of the bridge column regardless of the imposed loading history. To realize the accuracy and reliability of the proposed method, a hypothetical case study bridge was constructed and analyzed using various structural analysis programs and seismic evaluation methods. It was found that the proposed method can receive satisfactory estimates of the maximum displacement and for both far‐field and near‐fault ground motions when compared to the nonlinear time history analysis results of the bridge. In contrast, the AASHTO's and Caltrans’ methods cannot reflect the response amplification effects caused by the frequency‐content characteristics of near‐fault ground motions and would therefore significantly underestimate the inelastic responses of bridges. When applying the proposed method to bridges having unequal‐height columns and subjected to longitudinal seismic actions, it was found that for the short column of the bridge, the AASHTO's regularity criteria (maximum bent/pier stiffness ratio of 4 for the three‐span case study bridge) would lead to a of approximately 3.5 times that of the tall column, resulting in significant damage localization and, hence, decreasing the overall lateral deformation capacity of the bridge.
The use of Stick‐IT model for the prediction of direct economic losses
Authors: Gaetani d'Aragona Marco , Polese Maria , Di Ludovico Marco , Prota Andrea 
Published: January 2021

AbstractThe Stick‐IT model (Stick for Infilled frames Typologies), that is a MDOF system consisting of a series of lumped masses connected by nonlinear shear link elements, was introduced to predict the response, in terms of interstory drift ratio (IDR) and peak floor acceleration (PFA), for infilled RC building typologies. Stick model parameters can be defined starting from low level building geometrical features, easily retrievable at the large scale, such as in plan dimensions, number of stories or the percentage of infills openings and considering the infills consistency. This paper investigates the applicability of Stick‐IT to predict the performance and direct economic losses for existing RC infilled frame type buildings. In the framework of a performance‐based assessment, the comparison of seismic‐loss outcomes provided by using either a detailed finite element model (FEM) (L1) or simplified Stick‐IT structural models (L2) are illustrated and discussed. The potential of Stick‐IT model is investigated referring to a real building damaged and repaired after the 2009 L'Aquila earthquake and adopting as earthquake input records registered in the proximity of the building. Story‐level building damage simulated by L1 and L2 models is compared to real damage, showing satisfactory prediction. The comparison of the real repair costs with those evaluated using L1 and L2 models provides encouraging validation. The application suggests that simplified models such as Stick‐IT, despite the low level of information required for its application, can be usefully applied to perform damage and loss scenarios at the large scale. Matlab code to generate the Stick‐IT, as well as the example code for the present study, are openly shared through the repository https://github.com/marcogaetanidaragona/Stick-IT.
Deformation and damage of cement sheath in gas storage wells under cyclic loading
Authors: Li Juan , Su Donghua , Tang Shizhong , Li Zaoyuan , Wu Hua , Huang Sheng , Sun Jinfei 
Published: January 2021

AbstractThe mechanical damage and failure of cement sheaths in gas storage wells under cyclic loading have been studied extensively. However, because the test device cannot restore the wellbore condition, most studies have been theoretical or regular experimental. If the load‐bearing mode and stress environment in a test device differ from those in a wellbore, then the damage and failure modes will deviate from what occurs in the actual wellbore. Therefore, it is necessary to explore a method that restores the wellbore condition and design a wellbore simulation device that reveals the deformation and damage of the cement sheath. In this study, the development laws of microannulus and microcracks in the cement sheath were studied by triaxial cyclic loading, low‐field nuclear magnetic resonance imaging, and scanning electron microscopy. A device to evaluate cement sheath integrity was then developed. A stress equivalence method was proposed, based on the principle that the stresses at the first and second interfaces of the device are equal to those of the wellbore cement sheath. This method was used to design material, size, and experimental conditions to simulate the load‐deformation law of a cement sheath in a gas storage well. The damage failure mechanism was investigated using the simulation results and computed tomography. Micropores and microcracks in the cement sheath increased continuously under cyclic loading. Damage accumulated, causing strength failure as the period of the cyclic loading increased. Plastic deformation of the cement sheath occurred under cyclic loading, but interfacial peeling did not. The reason is that the cement sheath is under compressive stress during loading and unloading, and the interface between the cement sheath and the outer wall is not damaged. This study provides a new method for studying the mechanical failure of a cement sheath under complex wellbore conditions.
Effects of different modified atmosphere treatments on lipid oxidation in spiced beef at different storage temperatures
Authors: Hai Dan , Huang Xianqing , Song Lianjun 
Published: January 2021

AbstractThe high moisture and nutrient contents of spiced beef make it popular with consumers but present challenges for its storage, as spoilage is a common phenomenon. Therefore, for identifying packaging methods to reduce spoilage during storage, this study investigated the effects of 5% O2 (low oxygen), 70% CO2 (high carbon dioxide), and 5% O2/70% CO2/25% N2 (compound group) on lipid oxidation in spiced beef in the test groups and a vacuum‐packed group (control) at storage temperatures of 4, 25, and 60°C. The pH, thiobarbituric acid (TBA), anisidine value (AV), and peroxide value (POV) of the spiced beef were determined. Results indicated that 70% CO2 and storage at 4 and 25°C showed the strongest ability to inhibit the rancidity in spiced beef. The 5% O2 group delayed both initial oxidation and secondary oxidation of lipids. Although the compound group significantly inhibited the rancidity in spiced beef at 60°C, it could not maintain such inhibition for long. Among all the groups, the 70% CO2 group demonstrated maximum inhibition of initial lipid oxidation and suppressed the secondary oxidation of lipids for the longest time. Thus, the modified atmosphere packaging with O2 and CO2 can regulate the fat oxidation in meat products and effectively improve their flavor maintenance.
Occurrence of antibiotic‐resistant bacteria on hydroponically grown butterhead lettuce (Lactuca sativa var. capitata)
Authors: Srichamnong Warangkana , Kalambaheti Natcha , Woskie Susan , Kongtip Pornpimol , Sirivarasai Jintana , Matthews Karl R. 
Published: January 2021

AbstractAntibiotics used during production of food crops to control plant diseases may result in selection of antibiotic‐resistant bacteria and occurrence of antibiotic residues. The aim of this research was to evaluate the effect of antibiotics used in butterhead lettuce production on persistence of commensal microbiota. Butterhead lettuce were treated with antibiotics (oxytetracycline, gentamicin, and streptomycin) at different concentrations (100, 200, 300, 400 and 500 ppm) starting at 5 weeks’ growth by spraying once daily for 4 weeks and harvesting 7 days after the final spray application. The population of total aerobic bacteria and antibiotic‐resistant bacteria were determined. The results showed antibiotic usage significantly decreased bacterial populations on lettuce. Moreover, increased concentration of antibiotics resulted in significantly greater decrease in bacterial populations. At a concentration of 500 ppm, all antibiotics achieved an approximate 2 log CFU/g decrease in bacterial populations. A stable population (4 log CFU/g) of potentially antibiotic‐resistant commensal microbiota were maintained throughout production. Screening for level of susceptibility indicated that bacteria exhibited greater resistance to oxytetracycline than gentamicin. In conclusion, application of antibiotics failed to eliminate commensal microbiota, demonstrating large populations of antibiotic‐resistant bacteria reside on lettuce grown under conditions used in the present study. This is the first study focused on antibiotic usage on hydroponic systems. Results of this study suggest regulations directed at antibiotic use on food crops must be developed and implemented to control the selection and spread of antibiotic‐resistant bacteria that present a global health concern.