bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel 1,2,3‐triazolo phosphonate derivatives as potential antibacterial agents
Authors: Telu Jhonsee Rani , Kuntala Naveen , Kankanala Kavitha , Banothu Venkanna , Pal Sarbani , Anireddy Jaya Shree 
Published: January 2021

AbstractWe describe the synthesis, characterization, and in vitro antibacterial evaluation of a library of novel compounds based on 1,2,3‐triazolo phosphonate framework along with the evaluation of DNA gyrase inhibitory potential of a promising molecule in silico. Preparation of these compounds was carried out via a multistep sequence comprising of the Abramov reaction followed by the Cu(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) as the key steps. Various α‐hydroxyphosphonate derivatives containing either a secondary or tertiary alcohol at the α position were prepared. When screened for their antibacterial activities in vitro using a Gram‐positive (Staphylococcus aureus) and three Gram‐negative (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) strains, majority of these derivatives exhibited reasonable to good effects with the analogue 5k being active against all the strains. The SAR analysis indicated that the activity was influenced by the position of the α‐hydroxyphosphonate moiety as well as the substituent present on the benzene ring attached to the 1,2,3‐triazole ring. Moreover, the compound 5k showed strong interactions with the DNA active site when docked into the DNA gyrase in silico. Thus, the 1,2,3‐triazolo phosphonate derivative 5k appeared to be a novel and promising hit molecule that deserves further study as a potential antibacterial agent.
A rapid and cost‐effective multiplex ARMS‐PCR method for the simultaneous genotyping of the circulating SARS‐CoV‐2 phylogenetic clades
Authors: Islam Mohammad Tanvir , Alam ASM Rubayet Ul , Sakib Najmuj , Hasan Mohammad Shazid , Chakrovarty Tanay , Tawyabur Mohammad , Islam Ovinu Kibria , Al‐Emran Hassan M. , Jahid Mohammad Iqbal Kabir , Anwar Hossain Mohammad 
Published: January 2021

AbstractTracing the globally circulating severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) phylogenetic clades by high‐throughput sequencing is costly, time‐consuming, and labor‐intensive. We here propose a rapid, simple, and cost‐effective amplification refractory mutation system (ARMS)‐based multiplex reverse‐transcription polymerase chain reaction (PCR) assay to identify six distinct phylogenetic clades: S, L, V, G, GH, and GR. Our multiplex PCR is designed in a mutually exclusive way to identify V–S and G–GH–GR clade variants separately. The pentaplex assay included all five variants and the quadruplex comprised of the triplex variants alongside either V or S clade mutations that created two separate subsets. The procedure was optimized with 0.2–0.6 µM primer concentration, 56–60°C annealing temperature, and 3–5 ng/µl complementary DNA to validate on 24 COVID‐19‐positive samples. Targeted Sanger sequencing further confirmed the presence of the clade‐featured mutations with another set of primers. This multiplex ARMS‐PCR assay is a fast, low‐cost alternative and convenient to discriminate the circulating phylogenetic clades of SARS‐CoV‐2.
Purified anthocyanins from Zea mays L. cob ameliorates chronic liver injury in mice via modulating of oxidative stress and apoptosis
Authors: Cui Hong‐Xin , Luo Yang , Mao Yue‐Yue , Yuan Ke , Jin Song‐Heng , Zhu Xiang‐Tao , Zhong Bing‐Wei 
Published: January 2021

AbstractBACKGROUNDPurple corn (Zea mays L.) is one of the main economic crops in China and has been used in the treatment of cystitis, urinary infections and obesity. However, purple corncobs, the by‐product remaining after processing and having an intense purple‐black color, are normally disposed of as waste or used as animal feed. Therefore, to further expand the medicinal value of purple corncob, its content was analyzed and, after purification, the effect and mechanism of purified purple corncob anthocyanins (PPCCA) on CCl4‐induced chronic liver injury in mice were investigated.RESULTSIt was observed that the total anthocyanin content (TAC) from PPCCA (317.51 ± 9.30 mg cyanidin 3‐O‐glucoside (C‐3‐G) g−1 dry weight) was significantly higher than that from the purified purple corn seed anthocyanin (266.73 ± 3.67 mg C‐3‐G g−1 dry weight), of which C‐3‐G accounted for 90.6% and 90.4% of the TAC, respectively. Furthermore, compared with the CCl4 group, PPCCA treatment significantly reduced liver index, serum total bilirubin, alanine transaminase, aspartate transaminase and liver malondialdehyde levels, but increased liver superoxide dismutase activity. The pathological changes were also improved, such as more regular arrangement of hepatocytes, less swelling, and fewer vacuoles and apoptotic cells. Additionally, mechanistic studies showed that PPCCA downregulated the expression of Caspase‐3, Bax and cytochrome P450 2E1 proteins in the liver and upregulated the expression of Bcl‐2.CONCLUSIONThese results demonstrated that PPCCA could ameliorate CCl4‐induced chronic liver injury by regulating oxidative stress and hepatocyte apoptosis pathways. © 2021 Society of Chemical Industry
Synovitis and Tenosynovitis on Ultrasound as Predictors of DMARD Tapering Failure in Patients with Long‐Standing Rheumatoid Arthritis in Clinical Remission or Low Disease Activity
Authors: Massignan Ângela , Mendonça da Silva Chakr Rafael , Pamplona Bueno de Andrade Nicole , Brenol Claiton Viegas 
Published: January 2021

ObjectivesThis study aimed to investigate the predictive value of synovitis and tenosynovitis detected by grayscale (GS) and by power Doppler (PD) ultrasound (US) in relation to failure of tapering disease‐modifying antirheumatic drugs (DMARD) in rheumatoid arthritis (RA) patients.MethodsLong‐standing RA patients who de‐escalated treatment were included in this prospective cohort study. All patients underwent 3 ultrasonographic and clinical assessments, at baseline and every 3 or 4 months, over a period of 6–8 months. US investigation of 32 joints was performed. Synovitis was assessed by GS and PD semiquantitative scoring (0–3) and a global score was calculated for each individual by summing single joint scores. The presence of tenosynovitis was recorded whenever detected during ultrasound assessment.ResultsThirty‐three patients completed the follow‐up period (29 women; 4 men). Eight patients (25%) relapsed. Using the optimal cutoff values determined by receiver operating characteristic curve, patients with a PD synovitis ≥1 at baseline had significantly greater chances to relapse than those without PD activity. During follow‐up, GS tenosynovitis was detected in 6 patients (5 with PD) who failed and in 3 patients (1 with PD) who succeeded in tapering therapy. Having at least 1 joint with PD synovitis resulted in a relative risk of 3.14 and having GS tenosynovitis resulted in a relative risk of 11.4 (95% CI: 1.03–9.60 and 2.82–45.9, respectively) for relapse in the multivariate Poisson model.ConclusionsPD synovitis and GS tenosynovitis may be useful to identify RA patients in risk of relapse after DMARD tapering.
Grazing exclusion regulates bacterial community in highly degraded semiarid soils from the Brazilian Caatinga biome
Authors: de Araujo Pereira Arthur Prudêncio , Lima Lara Andrade Lucena , Bezerra Walderly Melgaço , Pereira Mirella Leite , Normando Leonardo Ribeiro Oliveira , Mendes Lucas William , de Oliveira Jose Gerardo Beserra , Araújo Ademir Sérgio Ferreira , Melo Vânia Maria Maciel 
Published: January 2021

AbstractGrazing exclusion has been applied as a suitable strategy for soil conservation worldwide, mainly on semiarid soils. However, it is unclear how grazing exclusion reduces the negative effects of overgrazing on the microbial community in the Caatinga biome. In our study, we assessed the bacterial community under three different soil managements in a semiarid region of the Brazilian Caatinga biome, as follows: (a) Native Caatinga vegetation (natural); (b) grazing exclusion (exclusion); and (c) overgrazing (grazed). The bacterial community was assessed through the sequencing of the V4 region of the 16S rRNA gene and analyzed soil chemical and physical properties were correlated with the bacterial community structure. Our results demonstrate that exclusion increases the content of soil carbon and nitrogen, and bacterial diversity, while grazed showed a reduction of ~31 and ~43% in organic C, compared to exclusion and natural, respectively. However, the changes in bacterial diversity were more expressive in a specific site (No. 1), suggesting that exclusion strategy could be a context‐dependent and complex approach to protecting or improving Caatinga soils. Moreover, grazed areas might restrain the potential of bacterial diversity to sustain ecosystem functions since nonbeneficial elements increased in grazed treatments, which presented a negative correlation with the bacterial community. Our study provides novel evidence that high‐intensity disturbance by overgrazing could not only reduce soil fertility but it may also restrain bacterial composition, with implications on ecosystem functioning. The Caatinga soil microbiome may be unable to maintain ecosystem services such as plant and animals' development under overgrazing management.
A Toughening and Anti‐Counterfeiting Benzotriazole‐Based High‐Performance Polymer Film Driven by Appropriate Intermolecular Coordination Force
Authors: Cao Liang , Yang Li , Xu Yewei , Yin Qiang , Huang Ying , Chang Guanjun 
Published: January 2021

AbstractIt is of great significance to circumvent the inherent trade‐off between strength and extensibility for epoxy resins. Herein dynamic Cu‐benzotriazole cross‐links are incorporated, as the appropriate intermolecular coordination interaction, into high performance epoxy networks, and the resulting epoxy resins exhibits outstanding thermal stability and mechanical properties, their strength and extensibility are simultaneously improved. Additionally, local manipulation of coordination crosslinking confers the film with anti‐counterfeiting function.
A free intercostal artery perforator flap as a salvage operation for a planned lumbar artery perforator flap with aberrant anatomy in breast reconstruction: A case report
Authors: Sharp Olivia L. , Köhler Guido , Masud Dhalia , Haywood Richard M. 
Published: January 2021

AbstractWhen autologous breast reconstruction is planned but abdominal tissue is not available, the lumbar artery perforator flap provides an alternative choice with minimal donor site morbidity. The lumbar and posterior intercostal arteries supply adjacent perforasomes on the posterolateral flank. The purpose of this report is to highlight the salvage of an autologous breast reconstruction free flap using a dorsal perforator of the posterior intercostal artery, when the planned lumbar artery perforators were not suitable. The patient was a 74‐year‐old with recurrent left‐sided breast cancer requiring immediate breast reconstruction. A lumbar perforator flap was planned as an oblique ellipse 19 × 10 cm. Intraoperatively, the two identified perforators traveled superiorly up to the 12th rib and therefore originated from the intercostal rather than lumbar arteries. The internal mammary artery and the vena comitants were used as recipient vessels, anastomosed to an interposition graft. Postoperatively, the patient was discharged home after 7 days without complication. Six months later, the patient was pleased with the reconstruction and had negligible donor site morbidity. The dorsal intercostal artery perforator flap therefore provides a salvage option when presumed lumbar artery perforators are dissected and found to be intercostal in origin.
A 21.5 ~ 25 GHz 7‐bit phase shifter with passive vector‐sum topology
Authors: Wu Tianjun , Zhang Xiaoning , Xing Zhao , Zhao Chenxi , Yu Yiming , Liu Huihua 
Published: January 2021

AbstractA 7‐bit passive phase shifter with low‐phase error is presented in 65 nm CMOS technology. The vector‐sum topology is implemented to enable passive phase shifter the ability of flexible phase calibration. Therefore, the passive phase shifter with high resolution and low‐phase error is achieved. In order to achieve high linearity, attenuator based on resistor is implemented to scale the I/Q signals, and a vector synthesizer based on balun is utilized to sum the quadrature vectors. Measurement results show that the phase shifter achieves 7‐bit resolution. The measured root mean square (RMS) phase error is <2.1°, and the RMS gain error is <1.2 dB over 21.5 ~ 25 GHz. The measured input‐referred P1dB is >10 dBm. The measured peak gain is about −14.3 dB, and the return loss is >8 dB. The chip has no DC power consumption and occupies an area of 880 × 500 um. The measurement results demonstrate the proposed phase shifter is very suitable for high linearity and high‐angular resolution phased arrays in K‐band.
Accurate and efficient algorithms with unconditional energy stability for the time fractional Cahn–Hilliard and Allen–Cahn equations
Authors: Liu Zhengguang , Li Xiaoli , Huang Jian 
Published: January 2021

AbstractComparing with the classic phase filed models, the fractional models such as time fractional Allen–Cahn and Cahn–Hilliard equations are equipped with Caputo fractional derivative and can describe more practical phenomena for modeling phase transitions. In this paper, we construct two accurate and efficient linear algorithms for the time fractional Cahn–Hilliard and Allen–Cahn equations with general nonlinear bulk potential. The main contribution is that we have proved the unconditional energy stability for the time fractional Cahn–Hilliard and Allen–Cahn models and their semi‐discrete schemes carefully and rigorously. Several numerical simulations in 2D and 3D are demonstrated to verify the accuracy and efficiency of our proposed schemes.
Learning‐Based Model Predictive Control for Multi‐Agent Systems using Gaussian Processes
Authors: Eschmann Hannes , Eberhard Peter 
Published: January 2021

AbstractModel Predictive Control (MPC), also referred to as Moving Horizon Control (MHC), experienced a massive growth of interest over the last decades due to increasing computing power and the ability to naturally incorporate state and input constraints. As a model‐based controller, the performance of Model Predictive Control heavily relies upon the quality of the model used. One can leverage measurement data to improve upon a nominal model, e.g., based on first principles, using Gaussian Processes, or other regression techniques. We instead opt for the introduction of (nonlinear) rate constraints to force the system to stay within regions of the state space where a simple, possibly linear, model describes the underlying dynamics well, while still robustly accounting for small model mismatches introduced with the simple model. These rate constraints can again be learned using any parametric or non‐parametric regression method, making the approach very flexible. As an exemplary system, we choose an omnidirectional mobile robot moving in an environment with changing friction coefficients, putting state‐dependent limits on the maximal rate of change of its speed.
Free‐edge delamination in composite laminates under tensile loading: An analytical closed‐form approach
Authors: Frey Christopher , Dölling Sebastian , Becker Wilfried 
Published: January 2021

AbstractIn the present study, interlaminar crack initiation in symmetric angle‐ply laminates under tensile loading is investigated using the coupled stress and energy criterion, whereby the required stress and energy quantities are determined by means of a new analytical closed‐form model. The identification of unknown interface fracture toughnesses is addressed by a parameter fit within physical reasonable limits. The resulting effective failure loads are compared to experimental data and show the high potential of the coupled criterion on the one hand and of the proposed analytical model on the other hand.
Application of a reduced basis method for an efficient treatment of structural mechanics problems
Authors: Bremm Sophia , Rosendahl Philipp L. , Becker Wilfried 
Published: January 2021

AbstractFor numerous problems in structural mechanics, a repeated solution of partial differential equations (PDEs), varying certain input parameters, is necessary. Solving the PDE for a large number of different input parameter sets using a full‐dimensional finite element method, requires repeated solving of large systems of equations and, thus, leads to a high computational effort. The aim of model order reduction techniques is to reduce the computational complexity in such calculations. In order to achieve this, the idea of the reduced basis method [1–3] is to replace the high‐dimensional model with a lower dimensional model, which is realized by forming a basis of solutions of the full problem for selected parameter sets. Key to determining suitable parameter sets is an appropriate error estimator.
Numerical treatment of the spike formation stage in marginally separated flows
Authors: Kuzdas Dominik , Braun Stefan 
Published: January 2021

AbstractThe method of matched asymptotic expansions is used to describe the so‐called ’by‐pass' transition in marginally separated boundary layer flows. Such flows may typically be observed e.g. on the suction side of a slender airfoil if the angle of attack is raised above a critical value. As a consequence, transition to turbulent flow is triggered by the repeated bursting of a laminar separation bubble. For asymptotically large Reynolds numbers the bursting of a laminar separation bubble can be described by various consecutive stages. The present work addresses the numerical solution of the triple deck stage succeeding a finite‐time blow‐up of the marginal separation stage. Although the corresponding evolution equations of the triple deck stage have been studied extensively by Elliott and Smith, a reliable numerical solution has not yet been presented. Special emphasis is placed on the formulation of the matching condition to the terminal structure of the preceding marginal separation stage.
Study of stochastic aspects in the modeling of the strain‐induced crystallization in unfilled polymers
Authors: Aygün Serhat , Klinge Sandra 
Published: January 2021

AbstractThe present contribution deals with the mechanical modeling of the crystallization of unfilled polymers under consideration of stochastic aspects of the process. The framework applied is thermodynamically consistent. The model involves the diameter of crystalline regions and the distance between these regions as internal variables. The necessary evolution equations are based on the assumptions for the effective free energy and the dissipation potential of a control volume. A distribution function is introduced to express the expectation value of relevant quantities. Furthermore, the numerical implementation of probability integrals is shown. The proposed concepts are of general nature and can be taken as a basis for the modeling of similar stochastic processes involving the evolution of the internal microstructure.
An RVE‐based investigation of thermoplastic vulcanizates exemplified by EPDM/PP
Authors: Sun Wanrong , Juhre Daniel 
Published: January 2021

AbstractIn this contribution, the material behaviour of thermoplastic vulcanizate is investigated using the example of ethylene‐propylene‐diene monomer rubber (EPDM) and polypropylene (PP). For modelling of viscoelastic effects, the generalized Maxwell element is applied, whereby the isochoric stresses of parallel Maxwell elements are determined via evolution equations. In order to take the morphological composition of TPV into account, a representative volume element (RVE) consisting of PP as matrix and EPDM as included material is considered. In a following numerical example, a cyclic shear test is presented, where the resulting force and stress distribution is evaluated. Thus, the results show the macroscopic material behaviour under the consideration of microstructure.
Implicit Analysis of Reissner–Mindlin shells with the Trace FEM
Authors: Schöllhammer Daniel , Fries Thomas-Peter 
Published: January 2021

AbstractThe linear Reissner–Mindlin shell is discretized with the Trace FEM. The geometry of the shell is implicitly defined by means of (multiple) level‐set functions. The implementational aspects of the Trace FEM, i.e., integration, stabilization and essential boundary conditions, are considered in detail resulting in a higher‐order accurate Trace FEM.
An Efficient Adjoint Sensitivity Analysis of Flexible Multibody Systems for a Level‐set‐based Topology Optimization
Authors: Azari Nejat Ali , Held Alexander , Seifried Robert 
Published: January 2021

AbstractFor large‐scale topology optimization of flexible multibody systems, only little results exist. This is due to the complexity of the modeling of the flexible bodies and the big effort to provide exact gradients. The considered flexible multibody systems can undergo both large nonlinear motions as well as small elastic deformations. Here, the flexible components are modeled by the floating frame of reference approach. For gradient calculation, the fully coupled adjoint sensitivity analysis is used, which is a semi‐analytical approach based on variational calculus. The computational effort strongly corresponds to the number of design variables. In this work, a design space reduction using radial basis functions is performed and the gradient of flexible components is constructed based on its exact value on a subset of selected design elements. In order to show the substantial gain in computation time, the exact and approximated gradient of a flexible crank in a slider‐crank mechanism are computed and applied for a level‐set‐based topology optimization.
Parametric FEM for computational homogenization of heterogeneous materials with random voids
Authors: Pivovarov Dmytro , Mergheim Julia , Willner Kai , Steinmann Paul 
Published: January 2021

AbstractComputational homogenization is a powerful tool which allows to obtain homogenized properties of materials on the macroscale from the simulation of the underlying microstructure. The response of the microstructure is, however, strongly affected by variations in the microstructure geometry. The effect of geometry variations is even stronger in cases when the material exhibits plastic deformations. In this work we study a model of a steel alloy with arbitrary distributed elliptic voids. We model one single unit cell of the material containing one single void. The geometry of the void is not precisely known and is modeled as a variable orientation of an ellipse. Large deformations applied to the unit cell necessitate a finite elasto‐plastic material model. Since the geometry variation is parameterized, we can utilize the method recently developed for stochastic problems but also applicable to all types of parametric problems — the isoparametric stochastic local FEM (SL‐FEM). It is an ideal tool for problems with only a few parameters but strongly nonlinear dependency of the displacement fields on parameters. Simulations demonstrate a strong effect of parameter variation on the plastic strains and, thus, substantiate the use of the parametric computational homogenization approach.