bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal‐Free Reductive Amination of Ketones with Amines Using Formic Acid as the Reductant under BF3 ⋅ Et2O Catalysis
Authors: Luo Zhenli , Wan Shanhong , Pan Yixiao , Yao Zhen , Zhang Xin , Li Bohan , Li Jiajie , Xu Lijin , Fan Qing‐Hua 
Published: January 2022

AbstractBF3 ⋅ Et2O has been found to effectively catalyze reductive amination of ketones with amines employing formic acid as the reductant under metal‐free conditions. This transformation tolerates a broad range of primary and secondary amines and differently decorated ketones, delivering N‐alkylated amines in good to excellent yields with high compatibility of functional groups. The synthetic potential of this protocol is demonstrated by its application in the preparation of biologically and pharmaceutically relevant compounds.
Interfacial Chemistry Triggers Ultrafast Radiative Recombination in Metal Halide Perovskites
Authors: Dong Haiyun , Zhang Chunhuan , Nie Weijie , Duan Shengkai , Saggau Christian N. , Tang Min , Zhu Minshen , Zhao Yong Sheng , Ma Libo , Schmidt Oliver G. 
Published: January 2022

AbstractEfficient radiative recombination is essential for perovskite luminescence, but the intrinsic radiative recombination rate as a basic material property is challenging to tailor. Here we report an interfacial chemistry strategy to dramatically increase the radiative recombination rate of perovskites. By coating aluminum oxide on the lead halide perovskite, lead–oxygen bonds are formed at the perovskite‐oxide interface, producing the perovskite surface states with a large exciton binding energy and a high localized density of electronic state. The oxide‐bonded perovskite exhibits a ≈500 fold enhanced photoluminescence with a ≈10 fold reduced lifetime, indicating an unprecedented ≈5000 fold increase in the radiative recombination rate. The enormously enhanced radiative recombination promises to significantly promote the perovskite optoelectronic performance.
Modulating Built‐In Electric Field via Variable Oxygen Affinity for Robust Hydrogen Evolution Reaction in Neutral Media
Authors: Zhai Lingling , She Xiaojie , Zhuang Lyuchao , Li Yanyong , Ding Ran , Guo Xuyun , Zhang Yongqi , Zhu Ye , Xu Kun , Fan Hong Jin , Lau Shu Ping 
Published: January 2022

AbstractWork function strongly impacts the surficial charge distribution, especially for metal‐support electrocatalysts when a built‐in electric field (BEF) is constructed. Therefore, studying the correlation between work function and BEF is crucial for understanding the intrinsic reaction mechanism. Herein, we present a Pt@CoOx electrocatalyst with a large work function difference (ΔΦ) and strong BEF, which shows outstanding hydrogen evolution activity in a neutral medium with a 4.5‐fold mass activity higher than 20 % Pt/C. Both experimental and theoretical results confirm the interfacial charge redistribution induced by the strong BEF, thus subtly optimizing hydrogen and hydroxide adsorption energy. This work not only provides fresh insights into the neutral hydrogen evolution mechanism but also proposes new design principles toward efficient electrocatalysts for hydrogen production in a neutral medium.
A Smart Theranostic Prodrug System Activated by Reactive Oxygen Species for Regional Chemotherapy of Metastatic Cancer
Authors: Liu Lingyan , Liu Feiyang , Liu Dongya , Yuan Wei , Zhang Mengfan , Wei Peng , Yi Tao 
Published: January 2022

AbstractMetastatic cancer is difficult to cure because of its uncontrollable nature and side effects during treatment. We constructed a reactive oxygen species (ROS)‐activated smart theranostic prodrug system based on an ROS active site linked with both a targeting group and an anticancer drug for efficient regional chemotherapy of metastatic cancers. The optimized prodrug (Bio‐(8)‐MB‐CPT) with biotin as the targeting group displayed high sensitivity towards ROS and selectively targeting ability towards cervical cancer cells, showing highly efficient drug release (up to 92 %) in vitro. Bio‐(8)‐MB‐CPT thus exerted strong toxicity towards cervical cancer cells, but unlike the parent drug (camptothecin), showed no toxicity towards normal cells. Moreover, the prodrug displayed significantly enhanced antitumor efficacy in vivo and eradicated the tumor with no obvious side effects (inhibition of the tumor reached up to 99.9 %).
Sample size determination for comparing accuracies between two diagnostic tests under a paired design
Authors: Hwang Yi‐Ting , Su Nan‐Cheng 
Published: January 2022

AbstractWith the progressive technology, many medical researches are aimed to develop diagnostic tests that can detect diseases faster and accurately. The assessment of the accuracy of the diagnostic test for classifying two groups is through the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC). When a paired design is considered, the sample size determination requires the information about two AUC estimates and the corresponding variance and covariance of two AUC estimators. This paper derives the nonparametric estimators of the variance and covariance of two AUC estimators. The result is used to derive the sample size formula when the paired sample is planned. Since most of the results do not have a closed form, numerical results are provided under various scenarios.
Simultaneous production of 2′‐fucosyllactose and difucosyllactose by engineered Escherichia coli with high secretion efficiency
Authors: Lee Hyun‐Jae , Shin Dong Joo , Han Kanghee , Chin Young‐Wook , Park Jong Pil , Park Kyeongsoon , Choi Chang‐Hyung , Park Bo‐Ram , Kim Soo‐Jung , Kim Sun‐Ki 
Published: January 2022

AbstractBackground and aimDifucosyllactose (Di‐FL) has strong antimicrobial activity against various pathogens, including group B Streptococcus, identified as the leading cause of neonatal sepsis. In this study, we sought to develop Escherichia coli as a microbial cell factory for efficiently producing Di‐FL as well as 2′‐fucosyllactose (2′‐FL), the most abundant fucosylated oligosaccharide in human milk, by utilizing the salvage guanosine 5′‐diphosphate (GDP)‐l‐fucose biosynthetic pathway.Main methods and major resultsThe biosynthetic pathway for producing fucosylated oligosaccharides via the salvage pathway requires two enzymes, l‐fucokinase/GDP‐l‐fucose phosphorylase (FKP) from Bacteroides fragilis and α‐1,2‐fucosyltransferase (FucT2) from Helicobacter pylori. To decrease the intracellular accumulation of 2′‐FL while increasing substrate accessibility to FKP and FucT2, we evaluated whether extracellular secretion of FKP and FucT2 would enhance the production of fucosylated oligosaccharides. Among various engineered strains constructed in this study, the ΔLFAR‐YA/FF+P‐PLA2 strain expressing phospholipase A2 (PLA2) from Streptomyces violaceoruber, whose native signal peptide was replaced with the PelB signal peptide (P‐PLA2), could secrete both FKP and FucT2 into the culture medium. Notably, it was observed that FKP and FucT2 present in the extracellular fraction could catalyze the synthesis of Di‐FL from lactose and fucose. As a result, a batch fermentation with the ΔLFAR‐YA/FF+P‐PLA2 strain resulted in the production of 1.22 ± 0.01 g L−1 Di‐FL and 0.47 ± 0.01 g L−1 2′‐FL, whereas the control strain could only produce 0.65 ± 0.01 g L−1 2′‐FL.Conclusions and implicationsThis study highlights the benefits of extracellular secretion of enzymes to improve biotransformation efficiency, as the transport of substrates and/or products across the cell membrane is limited.
Model‐driven design of synthetic N‐terminal coding sequences for regulating gene expression in yeast and bacteria
Authors: Wang Chenyun , Zhang Wei , Tian Rongzhen , Zhang Jianing , Zhang Linpei , Deng Zhaohong , Lv Xueqin , Li Jianghua , Liu Long , Du Guocheng , Liu Yanfeng 
Published: January 2022

AbstractN‐terminal coding sequences (NCSs) are key regulatory elements for fine‐tuning gene expression during translation initiation—the rate‐limiting step of translation. However, owing to the complex combinatory effects of NCS biophysical factors and endogenous regulation, designing NCSs remains challenging. In this study, a multi‐view learning strategy for model‐driven generation of synthetic NCSs for Saccharomyces cerevisiae and Bacillus subtilis are implemented, which are widely used in laboratories and industries. NCS libraries for S. cerevisiae and B. subtilis with nearly 150,000 cells were sorted. Next, model training was performed with NCS deep features extracted from DNA, codon, and amino acid sequences, as well as calculated features from the minimum free energy (MFE) and tRNA adaption index. Two models were separately developed for generating synthetic NCSs for both up‐ and down‐regulating gene expression with accuracies higher than 65% for S. cerevisiae and B. subtilis. Synthetic NCSs were then applied to enhance bioproduction, yielding 1.48‐ and 1.71‐fold production improvements of D‐limonene by S. cerevisiae and ovalbumin by B. subtilis, respectively. This work provides model‐driven design of synthetic NCSs as a toolbox for regulating gene expression in S. cerevisiae and B. subtilis. The machine learning‐based modeling approach can be used for NCS design in other microorganisms.
White matter microstructure alterations in frontotemporal dementia: Phenotype‐associated signatures and single‐subject interpretation
Authors: McKenna Mary Clare , Tahedl Marlene , Murad Aizuri , Lope Jasmin , Hardiman Orla , Hutchinson Siobhan , Bede Peter 
Published: January 2022

AbstractBackgroundFrontotemporal dementias (FTD) include a genetically heterogeneous group of conditions with distinctive molecular, radiological and clinical features. The majority of radiology studies in FTD compare FTD subgroups to healthy controls to describe phenotype‐ or genotype‐associated imaging signatures. While the characterization of group‐specific imaging traits is academically important, the priority of clinical imaging is the meaningful interpretation of individual datasets.MethodsTo demonstrate the feasibility of single‐subject magnetic resonance imaging (MRI) interpretation, we have evaluated the white matter profile of 60 patients across the clinical spectrum of FTD. A z‐score‐based approach was implemented, where the diffusivity metrics of individual patients were appraised with reference to demographically matched healthy controls. Fifty white matter tracts were systematically evaluated in each subject with reference to normative data.ResultsThe z‐score‐based approach successfully detected white matter pathology in single subjects, and group‐level inferences were analogous to the outputs of standard track‐based spatial statistics.ConclusionsOur findings suggest that it is possible to meaningfully evaluate the diffusion profile of single FTD patients if large normative datasets are available. In contrast to the visual review of FLAIR and T2‐weighted images, computational imaging offers objective, quantitative insights into white matter integrity changes even at single‐subject level.
A novel modified culture medium for enhancing redifferentiation of chondrocytes for cartilage tissue engineering applications
Authors: Sonthithai Pacharapan , Hankamonsiri Weerawan , Lertwimol Tareerat , Uppanan Paweena , Janvikul Wanida 
Published: January 2022

AbstractThe dedifferentiation of articular chondrocytes during in vitro expansion deteriorates the hyaline cartilage regeneration. Many approaches have been developed to enhance the redifferentiation of chondrocytes. In this study, a new and effective protocol to improve the redifferentiation of porcine chondrocytes in a pellet form was established. Pellets were initially treated in the modified culture media containing ternary mixtures, binary mixtures, or single reagents of sodium citrate (SCi), sodium chloride (SCh), and ethylenediaminetetraacetic acid (EDTA) at varied concentrations during the first 3 days of culture, followed by a normal culture medium until 21 days. Viability, proliferation, cartilaginous gene expression, extracellular matrix formation, and morphology of treated cell pellets were comparatively examined. Chondrocytes exposed to SCi, SCh, and EDTA individually or in combinations of two or three chemicals were non‐cytotoxic when the concentration ranges of the chemicals were 1.83–2.75, 5.00–7.50, and 1.00–1.50 mM, respectively. Cells treated with the modified media containing EDTA alone and EDTA‐containing mixtures enhanced glycosaminoglycan production as well as upregulated cartilaginous gene expression, despite their low proliferation rates. Overall, when all three reagents were in use, a pronounced synergistic effect on the activations of glycosaminoglycan accumulation and type II collagen production was explicitly observed at most, particularly when cells were cultured in the medium containing SCi, SCh, and EDTA at concentrations of 2.20, 6.00, and 1.20 mM, respectively. With a use of this protocol, the redifferentiation of articular chondrocytes for regeneration of hyaline cartilage for tissue engineering applications could be readily achieved.
Biochemical Characterization and Antimicrobial Activity against Some Human or Phyto‐Pathogens of New Diazonium Heterocyclic Metal Complexes
Authors: El‐Attar Mohamed S. , Elshafie Hazem S. , Sadeek Sadeek A. , El‐Farargy Ahmed F. , El‐Desoky Sameh I. , El‐Shwiniy Walaa H. , Camele Ippolito 
Published: January 2022

AbstractString of vanadium (IV), zirconium (IV), palladium (II), platinum (IV) and uranium (VI) chelates of 2‐cyano‐2‐[(2‐nitrophenyl)hydrazono]thioacetamide (Cnphta) were prepared and characterized by physicochemical, spectroscopic and thermal analyses. The formulae of the isolated solid complexes were assigned as [VO(Cnphta)2(H2O)]SO4 ⋅ 5H2O (1), [ZrO(Cnphta)2(H2O)]Cl2 ⋅ 4H2O (2), [Pd(Cnphta)2]Cl2 (3), [Pt(Cnphta)2Cl2]Cl2 (4) and [UO2(Cnphta)2](NO3)2 ⋅ 5H2O (5). The infrared assignments clearly showed that Cnphta ligand coordinated as a bidentate feature through the hydrazono nitrogen and the thioacetamide nitrogen for V(IV), Zr(IV) and U(VI) but displayed different behavior for Pd(II) and Pt(IV). Results of the molar conductivities measurements showed that the metal complexes were electrolytes in contrast with Cnphta ligand. The interpretation, mathematical analysis and evaluation of kinetic parameters were also carried out. In addition, the studied ligand and its new chelates were tested for their antimicrobial activity against some human or phytopathogenic microorganisms. The new metal complexes explicated promising antibacterial activity against all tested bacteria especially Staphylococcus aureus and Bacillus subtilis. Regarding the antifungal activity, all metal complexes were able to inhibit the mycelium growth of both tested pathogenic fungi. In particular Zr(IV) and Pt(IV) complexes showed the highest significant fungicidal effect against A. fumigatus similar to positive control.
Does the natural course of COVID‐19 infection include radiographic cystic changes?
Authors: Hirai Noriko , Kida Ryotaro , Yanada Hiraku 
Published: January 2022

AbstractA patient with late phase of COVID‐19 pneumonia presented peripheral cystic features on chest computed tomography, which were spontaneously resolved with no antibiotic therapy or surgery. Physicians should pay attention to follow up the late phase of COVID‐19 pneumonia for better understanding its progression and clinical course.
Chemo‐ and Enantioselective Photoenzymatic Ketone Reductions Using a Promiscuous Flavin‐dependent Nitroreductase
Authors: Prats Luján Alejandro , Bhat Mohammad Faizan , Saravanan Thangavelu , Poelarends Gerrit J. 
Published: January 2022

AbstractFlavoenzymes are oxidoreductases that catalyze an extensive range of different types of reactions. An advanced and powerful approach to achieving transformations that are normally outside the realm of flavoenzymes is the synergistic combination of photocatalysis and biocatalysis. Here we report the identification of a promiscuous flavin‐dependent nitroreductase, BaNTR1, that is able to promote enantioselective photobiocatalytic reductions of a broad range of structurally diverse ketones to yield the corresponding alcohols with high conversion (up to >99 %) and outstanding enantiopurity (up to >99 : 1 e.r). Noteworthy, BaNTR1 was able to promote the photoenzymatic reduction of various α,ß‐unsaturated ketones to give the corresponding optically pure alcohols without reducing the C=C or C≡C bond, illustrating its remarkably high chemoselectivity. Our results highlight the usefulness of photocatalysis for expanding the catalytic repertoire of nitroreductases to include highly enantio‐ and chemoselective reductions of non‐native ketone substrates to produce optically pure alcohols. This includes difficult to prepare allyl alcohols that are not accessible via photoenzymatic conversions using ene‐reductases.
Taguchi Optimization Studies for Abatement of 2‐Chlorophenol Using Neem Seed Activated Carbon
Authors: Mahapatra Manoj Kumar , Kumar Arvind 
Published: January 2022

AbstractThe abatement of 2‐chlorophenol (2CP) was carried out by an adsorption process using an economical, yet efficient activated carbon prepared from neem seeds activated carbon (NAC) as the adsorbent. The aim was to optimize the process parameters for 2CP adsorption onto NAC using Taguchi's optimization. An L9 orthogonal array was used for the optimization studies of the process parameters. The signal‐to‐noise ratio and F‐test values were the basis for selecting the significant parameters. The NAC was characterized using Brunauer‐Emmett‐Teller (BET), spectroscopic, microscopic, and X‐ray diffraction analysis. The BET surface area was found to be 246 m2g−1. Following the optimal conditions, an uptake capacity of 41 mg g−1 was observed. Finally, the regeneration studies revealed that the adsorption ability of NAC remained intact for up to three regeneration cycles.
Controlled, Sunlight‐Driven Reversible Cycloaddition of Multiple Singlet Oxygen Molecules to Anthracene‐Containing Trianglimine Macrocycles
Authors: Grajewski Jakub , Zgorzelak Mikołaj , Janiak Agnieszka , Taras‐Goślińska Katarzyna 
Published: January 2022

AbstractControlled release of singlet oxygen is of interest not only to chemists, but also to biologists and medics involved in cancer therapy. Two chiral polyaza macrocyclic compounds and their corresponding endoperoxides have been synthesized. These peroxides exhibit high temperature stability, up to 80 °C. Detailed studies on their structure, including X‐ray analysis as well as NMR, UV‐VIS ECD spectroscopy and theoretical calculations, combined with photochemical measurements indicate that their high stability is related to the arrangement of oxygen atoms in a conformationally stable macrocyclic ring. Despite the change of carbon hybridization from sp2 to sp3 at the 9 and 10 positions of the anthracene units, the macrocyclic skeleton of the obtained compounds does not change its conformation. The obtained endoperoxides can be formed and release singlet oxygen by irradiation with UV light of 365 and 275 nm, respectively. Release of the oxygen does not degrade the macrocyclic structure.
Confocal Imaging of Developing Leaves
Authors: Linh Nguyen Manh , Scarpella Enrico 
Published: January 2022

AbstractQuestions in developmental biology are most frequently addressed by using fluorescent markers of otherwise invisible cell states. In plants, such questions can be addressed most conveniently in leaves. Indeed, from the formation of stomata and trichomes within the leaf epidermis to that of vein networks deep into the leaf inner tissue, leaf cells and tissues differentiate anew during the development of each leaf. Moreover, leaves are produced in abundance and are easily accessible to visualization and perturbation. Yet a detailed procedure for the perturbation, dissection, mounting, and imaging of developing leaves has not been described. Here we address this limitation (1) by providing robust, step‐by‐step protocols for the local application of the plant hormone auxin to developing leaves and for the routine dissection and mounting of leaves and leaf primordia, and (2) by offering practical guidelines for the optimization of imaging parameters for confocal microscopy. We describe the procedure for the first leaves of Arabidopsis, but the same approach can be easily applied to other leaves of Arabidopsis or to leaves of other plants. © 2022 Wiley Periodicals LLC.Support Protocol 1: Preparation of plant growth mediumSupport Protocol 2: Preparation of growth medium platesBasic Protocol 1: Seed sterilization, sowing, and germination, and seedling growthSupport Protocol 3: Preparation of IAA–lanolin pasteBasic Protocol 2: Application of IAA–lanolin paste to 3.5‐DAG first leavesBasic Protocol 3: Dissection of 3‐ to 6‐DAG first leaves and leaf primordiaBasic Protocol 4: Dissection of 1‐ and 2‐DAG first‐leaf primordiaBasic Protocol 5: Mounting of dissected leaves and leaf primordiaSupport Protocol 4: Quality check of mounted leaves and leaf primordia by fluorescence microscopyBasic Protocol 6: Imaging of mounted leaves and leaf primordia by confocal microscopy
Ambient Processing Conditions and Their Effects on Perovskite Device Performance
Authors: Manspeaker Christopher , Merrion Garrett , Krouse Kevin , Zakhidov Alex 
Published: January 2022

AbstractPerovskite‐based solar devices have gained a worldwide development effort as they hold the potential of affordable solar power. This assumption is based on the inexpensive deposition and growth methods which are centered on ambient processing conditions. However, the data presented here indicate that the ambient conditions have a profound effect on the resulting device performance. Presented here are the effects of ambient conditions of temperature, pressure and solvent concentrations on device performance for devices grown using solvent engineering deposition methods. The results show that ambient conditions effect solvent evaporation rates which have a profound effect on device performance. Additionally, the Marangoni effect, described and observed here for the first time in perovskite solar devices, is also observed via its influence on the film parameters. Finally, the case is made that reliable and consistent perovskite devices will need a processing chamber to control the effects of temperature, pressure, and solvent conditions for perovskite devices to be truly commercializable.