bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sowing ratio determines forage yields and economic benefits of oat and common vetch intercropping
Authors: Wang Shang , Chen Gong , Yang Yadong , Zeng Zhaohai , Hu Yuegao , Zang Huadong 
Published: March 2021

AbstractMixtures of annual legumes with cereal grasses in forage production are considered to have great advantages and are extensively used in the agro–pastoral region of China. However, the effect of sowing ratio on forage yields and economic benefits of oat (Avena sativa L.) and common vetch (Vicia sativa L.) intercropping remains largely unknown. A 2 yr field experiment was conducted with seven sowing ratios (sowing ratio of oat as 0, 25, 33, 50, 67, 75, and 100%) for oat and common vetch intercropping in northeastern China. Intercropping showed significant advantages in forage yield, land equivalent ratio (LER), and net income in the 2 yr. Oat was the dominant partner in the mixtures, strongly outcompeting common vetch. A sowing ratio of oat at 50% produced the highest forage yields of 10.8–11.1 t ha‐1 in spring seeding and 4.9–7.7 t ha‐1 in summer seeding, which were 28.7–66.4% and 12.6–166.9% higher than those in monocultures, respectively, if we considered two years together. In any case, oat forage yield just slightly decreased with a decreasing share in the intercrops, whereas common vetch forage yields strongly decreased. The highest LERs were detected in a sowing ratio of oat at 50%, which was 11–57% higher than other sowing ratios. Similarly, the highest annual net incomes of US$1,336 and $1,088 ha‐1 were also obtained in a sowing ratio of oat at 50% in the 2 yr. In conclusion, oat and common vetch intercropping have greater forage yields and economic benefits compared with the corresponding monocultures in the agro–pastoral region of China, and a sowing ratio of oat at 50% is recommended.
Magnetization Transfer to Enhance NOE Cross‐Peaks among Labile Protons: Applications to Imino–Imino Sequential Walks in SARS‐CoV‐2‐Derived RNAs
Authors: Novakovic Mihajlo , Kupče Ēriks , Scherf Tali , Oxenfarth Andreas , Schnieders Robbin , Grün J. Tassilo , Wirmer‐Bartoschek Julia , Richter Christian , Schwalbe Harald , Frydman Lucio 
Published: March 2021

Abstract2D NOESY plays a central role in structural NMR spectroscopy. We have recently discussed methods that rely on solvent‐driven exchanges to enhance NOE correlations between exchangeable and non‐exchangeable protons in nucleic acids. Such methods, however, fail when trying to establish connectivities within pools of labile protons. This study introduces an alternative that also enhances NOEs between such labile sites, based on encoding a priori selected peaks by selective saturations. The resulting selective magnetization transfer (SMT) experiment proves particularly useful for enhancing the imino–imino cross‐peaks in RNAs, which is a first step in the NMR resolution of these structures. The origins of these enhancements are discussed, and their potential is demonstrated on RNA fragments derived from the genome of SARS‐CoV‐2, recorded with better sensitivity and an order of magnitude faster than conventional 2D counterparts.
Asymmetric Cobalt‐Catalyzed Regioselective Hydrosilylation/Cyclization of 1,6‐Enynes
Authors: You Yang'en , Ge Shaozhong 
Published: March 2021

AbstractWe report an enantioselective cobalt‐catalyzed hydrosilylation/cyclization reaction of 1,6‐enynes with secondary and tertiary hydrosilanes employing a catalyst generated in situ from the combination of Co(acac)2 and (R,Sp)‐Josiphos. A wide range of oxygen‐, nitrogen‐, and carbon‐tethered 1,6‐enynes reacted with Ph2SiH2, (EtO)3SiH, or (RO)2MeSiH to afford the corresponding chiral organosilane products in high yields and up to >99 % ee. This cobalt‐catalyzed hydrosilylation/cyclization also occurred with prochiral secondary hydrosilane PhMeSiH2 to yield chiral alkylsilanes containing both carbon‐ and silicon‐stereogenic centers with excellent enantioselectivity, albeit with modest diastereoselectivity. The chiral organosilane products from this cobalt‐catalyzed asymmetric hydrosilylation/cyclization could be converted to a variety of chiral five‐membered heterocyclic compounds by stereospecific conversion of their C−Si and Si−H bonds without loss of enantiopurity.
Structural and Molecular Dynamics Analysis of Plant Serotonin N‐Acetyltransferase Reveal an Acid/Base‐Assisted Catalysis in Melatonin Biosynthesis
Authors: Liao Lijing , Zhou Yuanze , Xu Youdong , Zhang Yuhao , Liu Xikai , Liu Biao , Chen Xinxin , Guo Yan , Zeng Zhixiong , Zhao Yucheng 
Published: March 2021

AbstractSerotonin N‐acetyltransferase (SNAT) is the key rate‐limiting enzyme in melatonin biosynthesis. It mediates melatonin biosynthesis in plants by using serotonin and 5‐methoxytryptamine (5‐MT), but little is known of its underlying mechanisms. Herein, we present a detailed reaction mechanism of a SNAT from Oryza sativa through combined structural and molecular dynamics (MD) analysis. We report the crystal structures of plant SNAT in the apo and binary/ternary complex forms with acetyl‐CoA (AcCoA), serotonin, and 5‐MT. OsSNAT exhibits a unique enzymatically active dimeric fold not found in the known structures of arylalkylamine N‐acetyltransferase (AANAT) family. The key residues W188, D189, D226, N220, and Y233 located around the active pocket are important in catalysis, confirmed by site‐directed mutagenesis. Combined with MD simulations, we hypothesize a novel plausible catalytic mechanism in which D226 and Y233 function as catalytic base and acid during the acetyl‐transfer reaction.
pH Feedback Lifecycles Programmed by Enzymatic Logic Gates Using Common Foods as Fuels
Authors: Fan Xinlong , Walther Andreas 
Published: March 2021

AbstractArtificial temporal signaling systems, which mimic living out‐of‐equilibrium conditions, have made large progress. However, systems programmed by enzymatic reaction networks in multicomponent and unknown environments, and using biocompatible components remain a challenge. Herein, we demonstrate an approach to program temporal pH signals by enzymatic logic gates. They are realized by an enzymatic disaccharide‐to‐monosaccharide‐to‐sugar acid reaction cascade catalyzed by two metabolic chains: invertase‐glucose oxidase and β‐galactosidase‐glucose oxidase, respectively. Lifetimes of the transient pH signal can be programmed from less than 15 min to more than 1 day. We study enzymatic kinetics of the reaction cascades and reveal the underlying regulatory mechanisms. Operating with all‐food grade chemicals and coupling to self‐regulating hydrogel, our system is quite robust to work in a complicated medium with unknown components and in a biocompatible fashion.
High‐Throughput Quality Control Assay for the Solid‐Phase Synthesis of DNA‐Encoded Libraries of Macrocycles**
Authors: Roy Animesh , Koesema Eric , Kodadek Thomas 
Published: March 2021

AbstractThere is considerable interest in the development of libraries of scaffold‐diverse macrocycles as a source of ligands for difficult targets, such as protein–protein interaction surfaces. A classic problem in the synthesis of high‐quality macrocyclic libraries is that some linear precursors will cyclize efficiently while some will not, depending on their conformational preferences. We report here a powerful quality control method that can be employed to readily distinguish between scaffolds that do and do not cyclize efficiently during solid‐phase synthesis of thioether macrocycles without the need for tedious liquid chromatography/mass spectrometry analysis. We demonstrate that this assay can be employed to identify linear impurities in a DNA‐encoded library of macrocycles. We also use the method to establish a useful quality control protocol for re‐synthesis of putative macrocyclic screening hits.
Residual Chlorine Induced Cationic Active Species on a Porous Copper Electrocatalyst for Highly Stable Electrochemical CO2 Reduction to C2+
Authors: Li Minhan , Ma Yuanyuan , Chen Jun , Lawrence Robert , Luo Wei , Sacchi Marco , Jiang Wan , Yang Jianping 
Published: March 2021

AbstractElectrochemical carbon dioxide (CO2) reduction reaction (CO2RR) is an attractive approach to deal with the emission of CO2 and to produce valuable fuels and chemicals in a carbon‐neutral way. Many efforts have been devoted to boost the activity and selectivity of high‐value multicarbon products (C2+) on Cu‐based electrocatalysts. However, Cu‐based CO2RR electrocatalysts suffer from poor catalytic stability mainly due to the structural degradation and loss of active species under CO2RR condition. To date, most reported Cu‐based electrocatalysts present stabilities over dozens of hours, which limits the advance of Cu‐based electrocatalysts for CO2RR. Herein, a porous chlorine‐doped Cu electrocatalyst exhibits high C2+ Faradaic efficiency (FE) of 53.8 % at −1.00 V versus reversible hydrogen electrode (VRHE). Importantly, the catalyst exhibited an outstanding catalytic stability in long‐term electrocatalysis over 240 h. Experimental results show that the chlorine‐induced stable cationic Cu0/Cu+ species and the well‐preserved structure with abundant active sites are critical to the high FE of C2+ in the long‐term run of electrochemical CO2 reduction.
Correlations in rheological behavior between large amplitude oscillatory shear and steady shear flow of silica‐filled star‐shaped styrene‐butadiene rubber compounds: Experiment and simulation
Authors: Pole Sandeep S. , Isayev Avraam I. 
Published: March 2021

AbstractThe large amplitude oscillatory shear (LAOS) and steady shear behavior of star‐shaped SSBR/silica 60 phr (21 vol%) compounds with various filler surface areas was measured and simulated. An SBR gum and SBR compounds containing four different silicas with surface areas of 55, 135, 160, and 195 m2/g were utilized. Rheological behavior indicated clear correlation with surface area. LAOS tests showed an increase in dynamic moduli, shear stress, and higher order harmonic contributions with surface area. Elastic and viscous Lissajous figures showed significant distortion at intermediate and higher strain amplitudes. Additionally, ratios of third and fifth order stress harmonics to the first stress harmonic (I3/1 and I5/1, respectively) showed a ''bump'' at intermediate strain amplitudes for the three highest surface area compounds. With regards to steady shear, all materials showed strong shear thinning behavior, and an increase in shear viscosity with surface area. The Cox‐Merz rule was shown to be valid for the SBR gum but not for the filled compounds. However, the complex viscosity as a function of shear rate amplitude at various frequencies at high strain amplitudes and the steady shear viscosity as a function of shear rate coincided. This correlation, referred to as the Philippoff approach, has important ramifications for the rubber industry, providing quick data for predicting processing behavior. The Simhambhatla‐Leonov model was successfully employed to simulate rheological behavior for the SBR gum and the lowest surface area silica compound, but the model yielded mixed results for the higher surface area silica compounds.
Sustained Remission in Patients With Rheumatoid Arthritis Receiving Triple Therapy Compared to Biologic Therapy: A Swedish Nationwide Register Study
Authors: Källmark Hanna , Einarsson Jon T. , Nilsson Jan‐Åke , Olofsson Tor , Saxne Tore , Geborek Pierre , C. Kapetanovic Meliha 
Published: March 2021

ObjectiveTo compare the real‐life effectiveness of biologic therapy (a biologic disease‐modifying antirheumatic drug plus methotrexate [MTX]) versus triple therapy (MTX plus sulfasalazine plus hydroxychloroquine/chloroquine) for sustained remission of rheumatoid arthritis (RA).MethodsRA patients who were registered in the nationwide Swedish Rheumatology Quality Register between 2000 and 2012 and were receiving biologic or triple therapy as a first treatment strategy after MTX monotherapy were included. Sustained remission was defined as a Disease Activity Score in 28 joints (DAS28) of <2.6 for ≥6 months (short‐term sustained remission) or for ≥24 months (long‐term sustained remission). Treatment groups were compared during treatment, at 1 year, and at 2 years for 1) all patients starting therapy and 2) patients continuing to receive therapy, using propensity score–adjusted regression analyses. In addition, survival analyses were used to compare treatment groups at any time during follow‐up irrespective of therapy retention.ResultsA total of 1,502 patients were included (1,155 receiving biologic therapy and 347 receiving triple therapy). For patients starting therapy, the adjusted odds ratios (ORs) of achieving short‐term and long‐term remission, respectively, at 1 year after start of biologic therapy versus triple therapy were 1.79 (95% confidence interval [95% CI] 1.18–2.71) and 1.86 (95% CI 1.00–3.48). At 2 years, the ORs were 1.92 (95% CI 1.21–3.06) and 1.62 (95% CI 0.94–2.79), respectively. For patients continuing to receive therapy, corresponding results at 1 year were 1.12 (95% CI 0.72–1.75) and 1.1 (95% CI 0.59–2.16); at 2 years, 0.85 (95% CI 0.49–1.47) and 0.76 (95% CI 0.41–1.39). Hazard ratios for short‐term and long‐term sustained remission at any time during follow‐up were 1.15 (95% CI 0.91–1.46) and 1.09 (95% CI 0.77–1.54), respectively.ConclusionAmong patients starting biologic or triple therapy, biologic therapy was more effective for remaining on therapy and achieving sustained remission. However, similar probabilities were found for achieving sustained remission among patients remaining on therapy and at any time during follow‐up irrespective of therapy retention. Although the likelihood of reaching sustained remission is higher with biologic therapy, for certain RA patients triple therapy may still be an alternative to biologic therapy without hampering future chances of obtaining sustained remission.
Leucht‐ und lautstark
Authors: Kaufmann Susanne 
Published: March 2021

AbstractFür den Hafen von Kenia hat der belgische Maschinen‐ und Anlagenbauer Meyland drei mobile Wiegetrichter gebaut, die zum Wiegen von Schüttgütern eingesetzt werden. Das Besondere an diesen Wiegetrichtern ist ihre enorme Größe: Sie sind jeweils 13 Meter hoch
Sprung in eine neue ära
Authors: Kraftschik Florian , Claus Jan‐Marten , Dietrich Peter 
Published: March 2021

AbstractDas Innovationstempo in der Stahlindustrie zieht kräftig an. Auch die Salzgitter Flachstahl GmbH setzt in der Produktion auf modernste Anlagentechnik. Jetzt hält das Industrial Internet of Things (IIoT) Einzug in die Kontibeize 2.
The Resting Oxidized State of Small Laccase Analyzed with Paramagnetic NMR Spectroscopy
Authors: Dasgupta Rubin , Gupta Karthick B. S. S. , de Groot Huub J. M. , Ubbink Marcellus 
Published: March 2021

AbstractThe enzyme laccase catalyzes the reduction of dioxygen to water at the trinuclear copper center (TNC). The TNC comprises a type‐3 (T3) and a type‐2 (T2) copper site. The paramagnetic NMR spectrum of the small laccase from Streptomyces coelicolor (SLAC) without the substrate shows a mixture of two catalytic states, the resting oxidized (RO) state and the native intermediate (NI) state. An analysis of the resonances of the RO state is reported. In this state, hydrogen resonances only of the T3 copper ligands can be found, in the region of 12–22 ppm. Signals from all six histidine ligands are found and can be attributed to Hδ1, Hβ or backbone amide HN nuclei. Two sequence‐specific assignments are proposed on the basis of a second‐coordination shell variant that also lacks the copper ion at the T1 site, SLAC−T1D/Q291E. This double mutant is found to be exclusively in the RO state, revealing a subtle balance between the RO and the NI states.
Diameter limits impede restoration of historical conditions in dry mixed‐conifer forests of eastern Oregon, USA
Authors: Johnston James D. , Greenler Skye M. , Miller Becky A. , Reilly Matthew J. , Lindsay Amanda A. , Dunn Christopher J. 
Published: March 2021

AbstractThe U.S. Forest Service is reconsidering policies that limit the size of trees that can be removed in the course of restoration treatments in dry forests of eastern Oregon. To evaluate the effects of diameter limits on the ability of managers to meet restoration objectives, we used an existing network of long‐term research plots to summarize historical and contemporary structure and composition of mixed‐conifer forests within a one million‐ha study area in eastern Oregon. Then, we used a novel thinning simulation procedure to quantify the degree to which thinning using different diameter limits restored stands to historical conditions. Contemporary mixed‐conifer forests within the study area are significantly denser, have more basal area, and have a greater proportion of shade‐tolerant species than historical conditions. Our simulations of thinning under current policy that prohibits cutting of trees ≥53 cm show that a quarter of mixed‐conifer stands cannot be restored to within the historical range of basal area or density. Those stands that could be restored to within historical basal area ranges still had a substantially higher component of shade‐tolerant trees than historical stands. Permitting larger shade‐tolerant trees to be removed allowed restoration of all or most of stands to within historical structural and compositional ranges. Forest conditions in the late 1800s may not necessarily provide the best template for management because climate and disturbance projections suggest that eastern Oregon forests will be less well suited to shade‐tolerant species in the future. Adapting stands to future conditions will require robust monitoring of forest structural and compositional response to restoration treatments.
A DFT Study on the Mechanism and Origin of Regioselectivity in the Rhodium/Diene‐Catalyzed Ring‐Opening Reactions of C1‐Substituted Oxabenzonorbornadienes with Arylboronic Acids
Authors: Pounder Austin , Bishop Fiona , Chen Leanne D. , Tam William 
Published: March 2021

AbstractThe mechanism and the origin of the regioselectivity of the rhodium/diene‐catalyzed ring‐opening reactions of C1‐substituted oxabenzonorbornadienes with arylboronic acids has been examined using hybrid density functional theory (DFT). The overall mechanism for the reaction is considered as a four‐step reaction including transmetalation, carborhodation, β‐oxygen elimination, and protonolysis. The free energy profiles show that the rate‐determining step is involved in the protonolysis step which differs from previous mechanistic studies on metal‐catalyzed ring‐opening reactions of oxabenzonorbornadienes. Additionally, it is theorized the β‐oxygen elimination step is the origin of regioselectivity. DFT calculations predict the formation of the 1,2,4‐trisubstituted naphthalene framework is selective over the 1,1,2‐trisubstituted product, in agreement with experimental observations.
Development of an Innovative Nitrite Sensing Platform Based on the Construction of an Electrochemical Composite Sensor of Polymer Coated CNTs and Decorated with Magnetite Nanoparticles
Authors: Atta Nada F. , Galal Ahmed , Ahmed Yousef M. , Abdelkader Mohamed G. 
Published: March 2021

AbstractElectrochemical determination of nitrite in real water samples is achieved using simple and efficient electrochemical sensor. The sensor is fabricated by electrodeposition of a thin layer of poly(3,4‐ethylenedioxythiophene) sandwiched by drop‐casting two thin layers of CNTs and iron oxide nanoparticles (Fe3O4) over a GC electrode surface. Voltammetry determination of nitrite in tap water and wastewater samples in the concentration range (0.5–150 μM) is successfully achieved with detection limits of 22 and 24 nM, respectively. Practical application of the GC/CNT/PEDOT/Fe3O4 sensor is efficiently assessed in real water samples for nitrite determination with acceptable recoveries, excellent anti‐interference ability and long‐term stability.
Do pharmaceutical prices rise anticipating branded competition?
Authors: Ellyson Alice M. , Basu Anirban 
Published: March 2021

AbstractGrowth in pharmaceutical prices is a major policy issue in the United States. Competition is encouraged to counteract such growth, yet less is known about the effect of brand competition on prices. We discover a unique feature of this market by studying the pricing strategies of incumbent drug manufacturers under tiered‐insurance anticipating branded competition. Using the insulin market as a natural experiment, we exploit exogenous variation in several potential entrants' completion of clinical trials to identify the effect of drug pipeline pressure on the prices of incumbent drugs. We find that pipeline pressure exerts cumulative and significant upward pressure on prices of incumbent drugs. In the insulin market such pressure explained 10.5% of the growth of prices. We were able to replicate these findings among incumbents with other emerging biosimilars. Insurance designs that fail to promote price competition through negotiations and value‐based principles may contribute to such price increases.
Novel thiazolidin‐4‐one clubbed thiophene derivatives via Gewald synthesis as anti‐tubercular and anti‐inflammatory agents
Authors: Nayak Soukhyarani Gopal , Poojary Boja , Kamat Vinuta , Puthran Divyaraj 
Published: March 2021

AbstractIn aim of obtaining novel bio‐active compounds, a new series of 5‐(3,5‐difluorophenyl)‐2‐(2‐imino‐5‐arylidene)‐4‐oxothiazolidin‐3‐yl)thiophene‐3‐carbonitrile (6a–d) and N‐(3‐cyano‐5‐(3,5‐difluorophenyl)thiophen‐2‐yl)‐2‐(substitutedamino)acetamide (7a–f) were synthesized via Gewald's method and characterized by 1H/13C nuclear magnetic resonance, Fourier‐transform infrared, mass spectrometry, and elemental analyses. All the newly prepared compounds were screened for their in vitro anti‐tubercular activity against virulent strain M. tuberculosis (H37Rv) at different concentrations ranging from 0.2 to 100 μg/ml. Most of the compounds were potent showing better inhibition at concentrations 6.25, 12.5, 25, 50, and 100 μg/ml. The anti‐inflammatory activity of the compounds was studied using inhibition of albumin denaturation technique. Tested compounds exhibited remarkable anti‐inflammatory activity. Hemolytic assay also confirmed that compounds are non‐toxic with a percentage hemolysis ranging from 1.81 to 14.94 at a concentration of 1 mg/ml. The results suggest that amino‐substituted acetamide and thiazolidin‐4‐one moiety, as well as the substitution pattern on the heterocyclic ring, have an effect on bioactivity.
High Tm Poly(l‐lactide)s by Means of Bismuth Catalysts?
Authors: Kricheldorf Hans R. , Meyer Andreas , Weidner Steffen M. 
Published: March 2021

AbstractOne series of BiSub‐catalyzed ring‐opening polymerizations (ROPs) is performed at 160 °C for 3 days with addition of difunctional cocatalysts to find out, if poly(l‐lactide) crystallizes directly from the reaction mixture. An analogous series is performed with monofunctional cocatalysts. High Tm crystallites (Tm > 190 °C) are obtained from all bifunctional cocatalysts, but not from all monofunctional ones. It is shown by means of SAXS measurements that the high Tm values are mainly a consequence of a transesterification–homogenization process across the lamellar surfaces resulting in thickness and smoothing of the surfaces. An unusual enthalpy‐driven modification of the molecular weight distribution is found for samples that have crystallized during the polymerization. A third series of ROPs is performed at 170 °C for 2 h followed by annealing at 120 °C (2 h) to induce crystallization. Complete transformation of the resulting low Tm crystallites (Tm < 180 °C) into the high Tm crystallites by annealing at 170 °C for 1 d is not achieved, despite variation of the cocatalyst.