185 research outputs found

    Copper-Catalyzed Regiospecific Synthesis of <i>N</i>-Alkylbenzimidazoles

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    A copper-catalyzed method is described for the preparation of N-alkylbenzimidazoles in regioisomerically pure form starting from o-haloanilines. The method utilizing CuI and trans-N,N‘-dimethyl-1,2-cyclohexanediamine allows the preparation of N-alkylbenzimidazoles in good to excellent yields

    Data_Sheet_1_How Learners’ Corrective Feedback Beliefs Modulate Their Oral Accuracy: A Comparative Study on High- and Low-Accuracy Learners of Chinese as a Second Language.pdf

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    This paper explores the differences in high-accuracy and low-accuracy learners’ beliefs about corrective feedback when learning Chinese as a second language (henceforth, CSL). In this study, we collected data through a questionnaire survey and an oral test with 76 CSL learners in a Chinese university. The analysis revealed that both high- and low-accuracy CSL learners shared the same beliefs in whether and how the learner errors should be corrected but differed in their beliefs about when is the best time to correct, which error should be corrected, and who the corrector should be. Specifically, the discrepancy between high- and low-accuracy groups’ beliefs about corrective feedback was found to be related to the participants’ oral accuracy. Our results confirm that learners’ CF beliefs can modulate their language accuracy. The corrective feedback beliefs held by high-accuracy groups have implications for improving low-accuracy groups’ oral accuracy. Through comparison with findings on corrective feedback beliefs of English as a foreign/second language (henceforth, EFL/ESL) learners, this study suggested that language pedagogies developed from the research of EFL/ESL learners’ CF beliefs should be able to shed light on this area and have significance for CSL learners. Implications for correcting learner errors in teaching CSL are also provided in the paper.</p

    A Photocatalyzed Cascade Approach Toward the Tetracyclic Core of Akuammiline Alkaloids

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    A cascade approach toward the tetracyclic core of akuammiline alkaloids which features high modularity and convergence is reported. Distinct substitution pattern can be readily introduced to the tetracyclic core by varying three building blocks with similar complexity. The critical event in the cascade is a regio- and stereoselective 1,2-shift enabled by a carbocation that sets up the core

    Tetraphenylsilane-Cored Star-Shaped Polymer Micelles with pH/Redox Dual Response and Active Targeting Function for Drug-Controlled Release

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    This paper presents the design and synthesis of star-shaped copolymers with two poly­[2-(diethylamino)­ethyl methacrylate] and poly­(ethylene glycol) blocks linked via a disulfide bond and each end of the four arms capped by folic acid (FA), from which the prepared nanodrug carriers simultaneously possess pH/redox dual response and active targeting functions. The polymer micelles exhibit excellent stability as reflected by their low critical micelle concentration values of 1.03–2.51 mg/L. The doxorubicin (DOX)-loaded polymer micelles are in the range of 108 to 143 nm, and the DOX-loading capacities are found to be up to 32.3%. The sensitive pH and redox responses are demonstrated by examining the drug release behaviors under the varied acidic condition from pH 7.4 to 5.0 and the glutathione concentrations from 0 to 10 mM, respectively. Moreover, the observation of confocal laser scanning microscopy confirms that the functionalization of arm ends by FA indeed enhances the internalization of DOX-loaded micelle particles in HeLa cells. As a result, the DOX-loaded nanocarriers can deliver therapeutic drugs to target HeLa cells, and the viability of HeLa cells (10.1%) approaches the value of the pristine DOX (9.98%), showing promising application as drug delivery nanocarriers for safe and highly efficient cancer therapy

    Formal Total Synthesis of (±)-Lycojaponicumin C

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    The formal total synthesis of (±)-lycojaponicumin C has been accomplished. Key transformations include a Rh-catalyzed formal [3 + 2] cycloaddition reaction to construct the bicyclic [3.3.0] scaffold bearing two vicinal quaternary carbon centers, a stereoselective γ-hydroxyl directed Michael addition to introduce the vinyl group at a bulky position, and a late-stage ring-closing metathesis reaction to form the cyclohexanone ring

    Table_1_Isolation and pan-genome analysis of Enterobacter hormaechei Z129, a ureolytic bacterium, from the rumen of dairy cow.XLSX

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    IntroductionUrea is an important non-protein nitrogen source for ruminants. In the rumen, ureolytic bacteria play critical roles in urea-nitrogen metabolism, however, a few ureolytic strains have been isolated and genomically sequenced. The purpose of this study was to isolate a novel ureolytic bacterial strain from cattle rumen and characterize its genome and function.MethodsThe ureolytic bacterium was isolated using an anaerobic medium with urea and phenol red as a screening indicator from the rumen fluid of dairy cattle. The genome of isolates was sequenced, assembled, annotated, and comparatively analyzed. The pan-genome analysis was performed using IPGA and the biochemical activity was also analyzed by test kits.ResultsA gram-positive ureolytic strain was isolated. Its genome had a length of 4.52 Mbp and predicted genes of 4223. The 16S rRNA gene and genome GTDB-Tk taxonomic annotation showed that it was a novel strain of Enterobacter hormaechei, and it was named E. hormaechei Z129. The pan-genome analysis showed that Z129 had the highest identity to E. hormaechei ATCC 49162 with a genome average nucleotide identity of 98.69% and possessed 238 unique genes. Strain Z129 was the first E. hormaechei strain isolated from the rumen as we know. The functional annotation of the Z129 genome showed genes related to urea metabolism, including urea transport (urtA-urtE), nickel ion transport (ureJ, tonB, nixA, exbB, exbD, and rcnA), urease activation (ureA-ureG) and ammonia assimilation (gdhA, glnA, glnB, glnE, glnL, glsA, gltB, and gltD) were present. Genes involved in carbohydrate metabolism were also present, including starch hydrolysis (amyE), cellulose hydrolysis (celB and bglX), xylose transport (xylF-xylH) and glycolysis (pgi, pgk, fbaA, eno, pfkA, gap, pyk, gpmL). Biochemical activity analysis showed that Z129 was positive for alkaline phosphatase, leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, α-glucosidase, β-glucosidase, and pyrrolidone arylaminase, and had the ability to use D-ribose, L-arabinose, and D-lactose. Urea-nitrogen hydrolysis rate of Z129 reached 55.37% at 48 h of incubation.DiscussionTherefore, the isolated novel ureolytic strain E. hormaechei Z129 had diverse nitrogen and carbon metabolisms, and is a preferred model to study the urea hydrolysis mechanism in the rumen.</p

    Datasheet1_Guidance on left bundle branch pacing using continuous pacing technique and changes in lead V1 characteristics under real-time monitoring.docx

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    BackgroundThe changes in the morphology and characteristics of the V1 leads during left bundle branch capturing still need to be fully understood.ObjectiveThis study aims to provide some suggestions about the LBB capture process through the morphology and characteristics of the V1 lead.MethodLBBP using the continuous pacing and morphology monitoring technique during screw-in using a revolving connector (John Jiang's connecting cable). The morphology and features of V1 leads are recorded by continuous monitoring technology.ResultsThe most common morphology in the LVSP stage is QR, while in the NS-LBBP (low output) stage and the NS-LBBP (lower output) stage, it is rSR. In the S-LBBP stage, it is rsR. The predominant morphology is with r/R waves in S-LBBP, which includes variations like rSR, rsR, rSr, rsr, rR, rs, rS, and R type, making up 96.7% of the total. The r waves in lead V1 are associated with agitated myocardium conducted from the left bundle branch.ConclusionThe initial r-wave in lead V1 may be a marker during the follow-up of patients with selective LBB capture.</p
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