bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isomers of B←N‐Fused Dibenzo‐azaacenes: How B←N Affects Opto‐electronic Properties and Device Behaviors?
Authors: Min Yang , Dou Chuandong , Tian Hongkun , Liu Jun , Wang Lixiang 
Published: November 2020

AbstractThe B←N unit has a large dipole and it is isoelectronic to C−C moiety with no dipole. Incorporating B←N units into π‐conjugated system is a powerful strategy to design organic small molecules and polymers with intriguing opto‐electronic properties and excellent opto‐electronic device performance. However, it is unclear how the B←N unit affects electronic structures and opto‐electronic properties of large π‐conjugated molecules. In this work, to address this question, we developed three dibenzo‐azaacene molecules in which two B←N units were introduced at different positions. Although the dibenzo‐azaacene skeleton is fully π‐conjugated, the effect of B←N unit on the electronic structures of the adjacent rings is much stronger than that of the distant rings. As a result, the three molecules with isomerized B←N incorporation patterns possess different electronic structures and exhibit tunable opto‐electronic properties. Among the three molecules, the centrosymmetrical molecule exhibits higher LUMO/HOMO energy levels than those of the two axisymmetrical molecules. When used as the active layer in organic field‐effect transistors (OFETs), while the two axisymmetrical molecules show unipolar electron transporting property, the centrosymmetrical molecule exhibits ambipolar hole and electron transporting behavior. This work not only deepens our understanding on organoboron π‐conjugated molecules, but also indicates a new strategy to tune opto‐electronic properties of organic semiconductors for excellent device performance.
Tris(pentafluoroethyl)difluorophosphorane: A Versatile Fluoride Acceptor for Transition Metal Chemistry
Authors: Föhrenbacher Steffen A. , Krahfuss Mirjam J. , Zapf Ludwig , Friedrich Alexandra , Ignat'ev Nikolai V. , Finze Maik , Radius Udo 
Published: November 2020

AbstractFluoride abstraction from different types of transition metal fluoride complexes [LnMF] (M=Ti, Ni, Cu) by the Lewis acid tris(pentafluoroethyl)difluorophosphorane (C2F5)3PF2 to yield cationic transition metal complexes with the tris(pentafluoroethyl)trifluorophosphate counterion (FAP anion, [(C2F5)3PF3]−) is reported. (C2F5)3PF2 reacted with trans‐[Ni(iPr2Im)2(ArF)F] (iPr2Im=1,3‐diisopropylimidazolin‐2‐ylidene; ArF=C6F5, 1 a; 4‐CF3‐C6F4, 1 b; 4‐C6F5‐C6F4, 1 c) through fluoride transfer to form the complex salts trans‐[Ni(iPr2Im)2(solv)(ArF)]FAP (2 a‐c[solv]; solv=Et2O, CH2Cl2, THF) depending on the reaction medium. In the presence of stronger Lewis bases such as carbenes or PPh3, solvent coordination was suppressed and the complexes trans‐[Ni(iPr2Im)2(PPh3)(C6F5)]FAP (trans‐2 a[PPh3]) and cis‐[Ni(iPr2Im)2(Dipp2Im)(C6F5)]FAP (cis‐2 a[Dipp2Im]) (Dipp2Im=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) were isolated. Fluoride abstraction from [(Dipp2Im)CuF] (3) in CH2Cl2 or 1,2‐difluorobenzene led to the isolation of [{(Dipp2Im)Cu}2]2+2 FAP− (4). Subsequent reaction of 4 with PPh3 and different carbenes resulted in the complexes [(Dipp2Im)Cu(LB)]FAP (5 a–e, LB=Lewis base). In the presence of C6Me6, fluoride transfer afforded [(Dipp2Im)Cu(C6Me6)]FAP (5 f), which serves as a source of [(Dipp2Im)Cu)]+. Fluoride abstraction of [Cp2TiF2] (7) resulted in the formation of dinuclear [FCp2Ti(μ‐F)TiCp2F]FAP (8) (Cp=η5‐C5H5) with one terminal fluoride ligand at each titanium atom and an additional bridging fluoride ligand.
Application of transesophageal echocardiography for localization in totally implantable venous access port implantation through subclavian approach in children
Authors: Yang Shujun , Kong Xiangru , Liu Lifei , Xu Ying , Zhang Jun 
Published: November 2020

AbstractA totally implantable venous access port (TIVAP) is important in children who need intravenous infusion for a long time. A number of studies have shown methods for locating the tip of the TIVAP catheter. To explore whether transesophageal echocardiography (TEE) can be used to accurately locate the TIVAP catheter tip through a subclavian approach and to improve the rate of correct TIVAP catheter placement and reduce complications of TIVAP placement. In 36 children who needed TIVAP implantation surgery, we used real‐time TEE guidance to place the catheter tip around the crista terminalis. In all children, chest X‐rays were used to figure out whether the catheter tip as localized by TEE was within the T5‐T7 segment. Then, we compared the length of the catheter calculated by the height formula and the actual catheter length applied under TEE guidance. The medical records, surgical details, nursing records, and recorded complications were collected during the follow‐up. The success rate of TIVAP implantation was 100% in all enrolled patients and no hemopneumothorax or pinch‐off syndrome occurred. Compared with TEE, chest X‐ray showed a coincidence rate of 80.56% in correctly detecting the TIVAP catheter tip locate. The height‐derived catheter length (11.0 [9.6, 11.8]) cm and the TEE‐derived catheter length (10.0 [9.3, 10.8]) cm were significantly different (p < .001). TEE can be used to guide TIVAP catheter positioning through a left subclavian approach in children accurately and successfully and more accurate than chest X‐ray and height calculation formula.
Design and Synthesis of Fused Pyridine Building Blocks for Automated Library Generation
Authors: Mora‐Radó Helena , Czechtizky Werngard , Méndez María , Harrity Joseph P. A. 
Published: November 2020

AbstractWe demonstrate that a diboration‐electrocyclization sequence provides access to a range of pyridine‐fused, small‐molecule boronic ester building blocks, and that these are amenable to high‐throughput synthesis leading to biaryl and ether‐linked compound libraries. Moreover, the implementation of an integrated physicochemical and ADME profiling workflow allows accelerated design of novel lead compounds for application in drug‐discovery projects.
Substituent effects on the photophysical properties of 2,9‐substituted phenanthroline copper(I) complexes: a theoretical investigation
Authors: Gourlaouen Christophe , Hamano Ai , Takano Keiko , Daniel Chantal 
Published: November 2020

AbstractThe electronic and nuclear structures of a series of [Cu(2,9‐(X)2‐phen)2]+ copper(I) complexes (phen=1,10‐phenanthroline; X=H, F, Cl, Br, I, Me, CN) in their ground and excited states are investigated by means of density functional theory (DFT) and time‐dependent (TD‐DFT) methods. Subsequent Born‐Oppenheimer molecular dynamics is used for exploring the T1 potential energy surface (PES). The T1 and S1 energy profiles, which connect the degenerate minima induced by ligand flattening and Cu−N bond symmetry breaking when exciting the molecule are calculated as well as transition state (TS) structures and related energy barriers. Three nuclear motions drive the photophysics, namely the coordination sphere asymmetric breathing, the well‐documented pseudo Jahn‐Teller (PJT) distortion and the bending of the phen ligands. This theoretical study reveals the limit of the static picture based on potential energy surfaces minima and transition states for interpreting the luminescent and TADF properties of this class of molecules. Whereas minor asymmetric Cu−N bonds breathing accompanies the metal‐to‐ligand‐charge‐transfer re‐localization over one or the other phen ligand, the three nuclear movements participate to the flattening of the electronically excited complexes. This leads to negligible energy barriers whatever the ligand X for the first process and significant ligand dependent energy barriers for the formation of the flattened conformers. Born‐Oppenheimer (BO) dynamics simulation of the structural evolution on the T1 PES over 11 ps at 300 K confirms the fast backwards and forwards motion of the phenanthroline within 200–300 fs period and corroborates the presence of metastable C2 structures.
Human‐engineered Treg‐like cells suppress FOXP3‐deficient T cells but preserve adaptive immune responses in vivo
Authors: Sato Yohei , Passerini Laura , Piening Brian D , Uyeda Molly Javier , Goodwin Marianne , Gregori Silvia , Snyder Michael P , Bertaina Alice , Roncarolo Maria‐Grazia , Bacchetta Rosa 
Published: November 2020

AbstractObjectivesGenetic or acquired defects in FOXP3+ regulatory T cells (Tregs) play a key role in many immune‐mediated diseases including immune dysregulation polyendocrinopathy, enteropathy, X‐linked (IPEX) syndrome. Previously, we demonstrated CD4+ T cells from healthy donors and IPEX patients can be converted into functional Treg‐like cells by lentiviral transfer of FOXP3 (CD4LVFOXP3). These CD4LVFOXP3 cells have potent regulatory function, suggesting their potential as an innovative therapeutic. Here, we present molecular and preclinical in vivo data supporting CD4LVFOXP3 cell clinical progression.MethodsThe molecular characterisation of CD4LVFOXP3 cells included flow cytometry, qPCR, RNA‐seq and TCR‐seq. The in vivo suppressive function of CD4LVFOXP3 cells was assessed in xenograft‐versus‐host disease (xeno‐GvHD) and FOXP3‐deficient IPEX‐like humanised mouse models. The safety of CD4LVFOXP3 cells was evaluated using peripheral blood (PB) humanised (hu)‐ mice testing their impact on immune response against pathogens, and immune surveillance against tumor antigens.ResultsWe demonstrate that the conversion of CD4+ T cells to CD4LVFOXP3 cells leads to specific transcriptional changes as compared to CD4+ T‐cell transduction in the absence of FOXP3, including upregulation of Treg‐related genes. Furthermore, we observe specific preservation of a polyclonal TCR repertoire during in vitro cell production. Both allogeneic and autologous CD4LVFOXP3 cells protect from xeno‐GvHD after two sequential infusions of effector T cells. CD4LVFOXP3 cells prevent hyper‐proliferation of CD4+ memory T cells in the FOXP3‐deficient IPEX‐like hu‐mice. CD4LVFOXP3 cells do not impede in vivo expansion of antigen‐primed T cells or tumor clearance in the PB hu‐mice.ConclusionThese data support the clinical readiness of CD4LVFOXP3 cells to treat IPEX syndrome and other immune‐mediated diseases caused by insufficient or dysfunctional FOXP3+ Tregs.
Chitosan‐based fluorescein isothiocyanate film as a highly efficient metal‐free photocatalyst for solar‐light‐mediated direct CH arylation
Authors: Singh Pooja , Yadav Rajesh K. , Kim Tae Wu , Kumar Abhishek , Dwivedi D. K. 
Published: November 2020

SummaryDevelopment of ecofriendly and low‐cost highly efficient photocatalysis is of importance in the field of chemical synthesis. Currently, various metals‐based organic materials, metal oxide nanoparticles, and metal nanomaterials have been urbanized as light harvesting photocatalysts for direct carbon (C)‐hydrogen (H) arylation of aryl diazonium salts and heteroarenes. These light harvesting photocatalysts, however, still suffer from poor stability, reusability problem, high cost, or less selectivity. Herein, we report the fabrication of a novel chitosan‐based fluorescein isothiocyanate (CBFITC) film photocatalyst and demonstrate its tremendous photocatalytic activity, high yields (97 ± 0.015%), selectivity (99%), and reusability to catalyze the metal free solar‐light‐mediated direct CH arylation of aryl diazonium salts and heteroarenes at ambient temperature. Moreover, CBFITC film photocatalyst can be recycled more than five times without loss of activity, verifying this photocatalyst excellent light harvesting ability and stability. The present approach to fabricate a metal‐free film photocatalyst with the suitable band gap will be a new platform for efficient photocatalytic reaction and provide a new insight into the solar chemical synthesis.
Combining design of experiments, machine learning, and principal component analysis for predicting energy consumption and product quality of a natural gas processing plant
Authors: Khoshnevisan Ladan , Hourfar Farzad , Alhameli Falah , Elkamel Ali 
Published: November 2020

SummaryProcessing natural gas, as a widely used source of energy in our life, is imperative to eliminate the impurities in order to make it consumable. So, appropriate modeling of different units in a real gas processing plant (GPP) is an essential research field. Moreover, high‐dimensional data, with probably unnecessary information, gathered from a real application may lead to complicated models. As a result, the original dataset, obtained through a three‐level design of experiments, should be refined to achieve the most effective observations in a lower dimension vector space. On the other hand, the original dataset needs to be normalized to a standard normal distribution in order to tune the effects of all the variables on the system operation. In this study a radial basis function‐neural network (RBF‐NN) is designed to model the total consumed energy in separation, sweetening, and dehydration units and also the water content in the refined gas in a typical GPP, using a reduced dimension dataset achieved by applying principal component analysis (PCA) on the normalized data. The proposed procedure is evaluated through some well‐known and standard criteria such as error relative deviation, root mean square error, the percentage of the average absolute relative deviation %AARD, sum of squared error, standard deviation, and correlation factor (R2). Simulation and analytical results demonstrate that the designed PCA‐RBF‐NN procedure can precisely model the dynamics of energy consumption and the final water content in a typical GPP with the confidence level of 98.6% through six principal components achieved by PCA technique. Furthermore, small values of the error measurements are obtained while using the developed RBF‐NN model.
Metal‐organic framework‐derived carbon‐cobalt oxysulfide nanocage heterostructure electrode for efficient hybrid supercapacitors
Authors: Ranjith Kugalur Shanmugam , Raju Ganji Seeta Rama , Kwak Cheol Hwan , Ghoreishian Seyed Majid , Huh Yun Suk , Im Ji Sun , Han Young‐Kyu 
Published: November 2020

SummaryConstruction of hybrid supercapacitors (HSCs) with defect engineered electrodes derived from single metal‐organic frameworks (zeolitic imidazolate frameworks, ZIF‐67) via control of the thermal influences showed unique structural features and rich electrochemical properties. Designing the three‐dimensional Co oxysulfide nanograins with carbon frame (CoOS‐C)‐based positive electrode surfaces through sulfidation with tunable defect states along with N‐ and S‐doping states improved the electrical energy storage; further, the possibility of having a carbon‐based skeleton surface influenced the effective rate capability during the charge‐discharge process. This unique nanostructural feature with encapsulation of porous N‐ and S‐doped graphitic carbon enabled improved rate performance by enhancing the stability of the electrode material and shortening the ion‐diffusion paths by the synergistic effect. Owing to the tunable defect functionality, the CoOS‐C based electrode exhibited a high storage capacity of 708.8 C g−1 at 1 A g−1 and an excellent rate capability with long‐term cyclic stability, with more than 93% capacity retention after 3000 cycles. Furthermore, the fabricated HSCs operated within a wide potential window of 1 to 1.6 V, which allowed excellent rate capability with a high‐energy density of 31.7 W h kg−1 at a specific power density of 800 W kg−1 with long‐term cyclic stability up to 10 000 cycles.
Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies
Authors: Gataullin Rail R. 
Published: November 2020

AbstractThe review covers the results of studies published in the literature on the synthesis of spiro‐linked heterocycles of the indole, quinoline, benzoxazine, benzothiazine, indenoquinoxaline, pyridopyrimidine, and acridine series. Possible approaches to the synthesis of spirocycles through a sequence of well‐known Knoevenagel, Michael reactions, deamination cyclization of 1,2‐dicarbonyl, CH‐acid compounds, direct cycloaddition of activated olefins to isatins, 3‐alkylideneindoles, 2‐oxindoles, in situ generated azomethine ylides, indenoquinoxalines are analyzed. Attention is drawn to approaches to the preparation of spiro‐fused compounds using reactions of intra‐ and intermolecular dearomatization of indoles. Recent advances in the synthesis of spiro‐linked benzo heterocycles from derivatives of 2‐olefin substituted anilines are summarized. The examples of the synthesis of spiro‐fused heterocycles by means of metal complexes catalyzed decomposition of diazo compounds are given. Some syntheses of biologically active representatives are shown, as well as the use of transformations of spiroheterocycles in the preparation of other heterocycles.
Synthesis of 3‐(trifluoromethyl)‐1‐(perfluorophenyl)‐1H‐pyrazol‐5(4H)‐one derivatives via Knoevenagel condensation and their biological evaluation
Authors: Dengale Sujata G. , Akolkar Hemantkumar N. , Karale Bhausaheb K. , Darekar Nirmala R. , Mhaske Sadhana D. , Shaikh Mubarak H. , Raut Dipak N. , Deshmukh Keshav K. 
Published: November 2020

AbstractIn search of new active molecules, a small focused library of the synthesis of 3‐(trifluoromethyl)‐1‐(perfluorophenyl)‐1H‐pyrazol‐5(4H)‐one derivatives (4a‐d, 5a‐f, and 6a‐e) has been efficiently prepared via the Knoevenagel condensation approach. All the derivatives were synthesized by conventional and nonconventional methods like ultrasonication and microwave irradiation, respectively. Several derivatives exhibited excellent anti‐inflammatory activity compared to the standard drug. Furthermore, the synthesized compounds were found to have potential antioxidant activity. In addition, to rationalize the observed biological activity data, an in silico absorption, distribution, metabolism, and excretion (ADME) prediction study also been carried out. The results of the in vitro and in silico studies suggest that the 3‐(trifluoromethyl)‐1‐(perfluorophenyl)‐1H‐pyrazol‐5(4H)‐one derivatives (4a‐d, 5a‐f, and 6a‐e) may possess the ideal structural requirements for the further development of novel therapeutic agents.
Endoplasmic reticulum stress and oxidative stress drive endothelial dysfunction induced by high selenium
Authors: Zachariah Matshediso , Maamoun Hatem , Milano Larissa , Rayman Margaret P. , Meira Lisiane B. , Agouni Abdelali 
Published: November 2020

AbstractSelenium is an essential trace element important for human health. A balanced intake is, however, crucial to maximize the health benefits of selenium. At physiological concentrations, selenium mediates antioxidant, anti‐inflammatory, and pro‐survival actions. However, supra‐nutritional selenium intake was associated with increased diabetes risk leading potentially to endothelial dysfunction, the initiating step in atherosclerosis. High selenium causes apoptosis in cancer cells via endoplasmic reticulum (ER) stress, a mechanism also implicated in endothelial dysfunction. Nonetheless, whether ER stress drives selenium‐induced endothelial dysfunction, remains unknown. Here, we investigated the effects of increasing concentrations of selenium on endothelial cells. High selenite reduced nitric oxide bioavailability and impaired angiogenesis. High selenite also induced ER stress, increased reactive oxygen species (ROS) production, and apoptosis. Pretreatment with the chemical chaperone, 4‐phenylbutyrate, prevented the toxic effects of selenium. Our findings support a model where high selenite leads to endothelial dysfunction through activation of ER stress and increased ROS production. These results highlight the importance of tailoring selenium supplementation to achieve maximal health benefits and suggest that prophylactic use of selenium supplements as antioxidants may entail risk.
Automated magnetic resonance image segmentation of the anterior cruciate ligament
Authors: Flannery Sean W. , Kiapour Ata M. , Edgar David J. , Murray Martha M. , Fleming Braden C. 
Published: November 2020

AbstractThe objective of this study was to develop an automated segmentation method for the anterior cruciate ligament that is capable of facilitating quantitative assessments of the ligament in clinical and research settings. A modified U‐Net fully convolutional network model was trained, validated, and tested on 246 Constructive Interference in Steady State magnetic resonance images of intact anterior cruciate ligaments. Overall model performance was assessed on the image set relative to an experienced (>5 years) “ground truth” segmenter in two domains: anatomical similarity and the accuracy of quantitative measurements (i.e., signal intensity and volume) obtained from the automated segmentation. To establish model reliability relative to manual segmentation, a subset of the imaging data was resegmented by the ground truth segmenter and two additional segmenters (A, 6 months and B, 2 years of experience), with their performance evaluated relative to the ground truth. The final model scored well on anatomical performance metrics (Dice coefficient = 0.84, precision = 0.82, and sensitivity = 0.85). The median signal intensities and volumes of the automated segmentations were not significantly different from ground truth (0.3% difference, p = .9; 2.3% difference, p = .08, respectively). When the model results were compared with the independent segmenters, the model predictions demonstrated greater median Dice coefficient (A = 0.73, p = .001; B = 0.77, p = NS) and sensitivity (A = 0.68, p = .001; B = 0.72, p = .003). The model performed equivalently well to retest segmentation by the ground truth segmenter on all measures. The quantitative measures extracted from the automated segmentation model did not differ from those of manual segmentation, enabling their use in quantitative magnetic resonance imaging pipelines to evaluate the anterior cruciate ligament.
Tetrachloroethene respiration in Sulfurospirillum species is regulated by a two‐component system as unraveled by comparative genomics, transcriptomics, and regulator binding studies
Authors: Esken Jens , Goris Tobias , Gadkari Jennifer , Bischler Thorsten , Förstner Konrad U. , Sharma Cynthia M. , Diekert Gabriele , Schubert Torsten 
Published: November 2020

AbstractEnergy conservation via organohalide respiration (OHR) in dehalogenating Sulfurospirillum species is an inducible process. However, the gene products involved in tetrachloroethene (PCE) sensing and signal transduction have not been unambiguously identified. Here, genome sequencing of Sulfurospirillum strains defective in PCE respiration and comparative genomics, which included the PCE‐respiring representatives of the genus, uncovered the genetic inactivation of a two‐component system (TCS) in the OHR gene region of the natural mutants. The assumption that the TCS gene products serve as a PCE sensor that initiates gene transcription was supported by the constitutive low‐level expression of the TCS operon in fumarate‐adapted cells of Sulfurospirillum multivorans. Via RNA sequencing, eight transcriptional units were identified in the OHR gene region, which includes the TCS operon, the PCE reductive dehalogenase operon, the gene cluster for norcobamide biosynthesis, and putative accessory genes with unknown functions. The OmpR‐family response regulator (RR) encoded in the TCS operon was functionally characterized by promoter‐binding assays. The RR bound a cis‐regulatory element that contained a consensus sequence of a direct repeat (CTATW) separated by 17 bp. Its location either overlapping the −35 box or 50 bp further upstream indicated different regulatory mechanisms. Sequence variations in the regulator binding sites identified in the OHR gene region were in accordance with differences in the transcript levels of the respective gene clusters forming the PCE regulon. The results indicate the presence of a fine‐tuned regulatory network controlling PCE metabolism in dehalogenating Sulfurospirillum species, a group of metabolically versatile organohalide‐respiring bacteria.