bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constructing Nanocaged Enzymes for Synergistic Catalysis of CO2 Reduction
Authors: Jia Zhichao , Dang Jianan , Wen Guobin , Zhang Yanxing , Chen Zhongwei , Bai Zhengyu , Yang Lin 
Published: May 2023

AbstractPromoting the activity of biological enzymes under in vitro environment is a promising technique for bioelectrocatalytic reactions, such as the conversion of carbon dioxide (CO2) into valuable chemicals, which is a promising strategy to address the environmental issue of CO2 in the atmosphere; however, this technique remains challenging. Herein, a nanocage structure for enzyme confinement is synthesized to enable the in situ encapsulation of formate dehydrogenase (FDH) in a porous metal–organic framework, which acts as a coenzyme and boosts the hybrid synergistic catalysis using enzymes. This study reveals that the synthesized FDH@ZIF‐8 nanocage‐structured hybrid (CSH) catalyst exhibits an improved catalytic ability of the enzymes and increases the hydrophobicity of the electrode and its affinity to CO2. Thus, CSH can trap CO2 and control its microenvironments. The CSH catalyst boosts the conversion rate of CO2 to formic acid (HCOOH) to 28 times higher than that when using pure FDH. The in situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) spectra indicates that OCHO* is the key intermediate. Density functional theory (DFT) calculations show that CSH has extremely low overpotential and is particularly effective for producing formate. This protection architecture for enzymes considerably promotes their biological application under in vitro environments.
Calcium plus vitamin D supplementation during pregnancy reduces postpartum fat mass in adolescents: A randomized trial
Authors: Rached Verônica , Diogenes Maria Eduarda Leão , Donangelo Carmen Marino , Bezerra Flávia Fioruci 
Published: May 2023

AbstractBackgroundPregnancy during adolescence may increase the risk of overweight/obesity. There is evidence that increasing calcium intake, alone or vitamin D‐combined, may favor loss of weight and/or fat mass.ObjectivesWe hypothesized that calcium supplementation during pregnancy reduces excessive fat accumulation during postpartum period. We aimed to investigate the effect of calcium plus vitamin D supplementation during pregnancy on body composition measurements throughout 1 year postpartum in Brazilian adolescents with habitually low calcium intake (~600 mg/day).MethodsAdolescents (14–19 years) were randomly assigned to receive a daily supplement (600 mg of calcium plus 200 UI of cholecalciferol, n = 30) or a placebo (n = 26) from 26 weeks of gestation until parturition. Body composition was determined at 5, 20, and 56 weeks postpartum by dual‐energy x‐ray absorptiometry. The effects of intervention group, time point, as well as their interaction were assessed using repeated measures mixed‐effects models.ResultsIn the adjusted analysis, those supplemented showed lower total body mass [mean difference = −3.32 kg; confidence interval (CI) 95% −6.12 to −0.52 kg], trunk (−1.25 kg; CI 95% −2.34 to −0.15 kg), android (−0.29 kg; CI 95% −0.53 to −0.04 kg) and subcutaneous (−0.23 kg; CI 95% −0.43 to −0.03 kg) fat masses. In the supplemented group, BMI and postpartum weight retention significantly decreased from 5 to 20 weeks (−0.90 kg/m2 and −1.76 kg, respectively; p < .05). At 56 weeks, BMI was still lower (−1.22 kg/m2; p < .05) than 5 weeks.ConclusionsOur findings suggest that increasing calcium intake through supplementation in combination with vitamin D contributes to a more pronounced reduction in total body mass overtime, mostly as a consequence of fat mass reductions in central body regions. This trial was registered at clinicaltrials.gov as NCT01732328.
Abnormal NHC Palladium(II) Complex Containing CNN Pincer Skeleton and Its Application to Suzuki‐Miyaura Coupling of Aryl Chlorides in Water
Authors: Saini Vaishali , Madduluri Vimal Kumar , Pragya  , Rangan Krishnan , Khungar Bharti 
Published: May 2023

AbstractThe excellent catalytic activities of abnormal NHC carbene complexes, where the C2 position remains unaffected, and coordination occurs at the C4 or C5 position of the imidazolium ring, is still a fascinating but scarce area of research. This present work reports a palladium complex (LPdBr) bearing abnormal NHC with CNN pincer architecture. It is synthesized from imidazolium‐based quinoline ligand (LH) with Pd(OAc)2 via ‐NH and carbene deprotonation. The complex was fully characterized by NMR spectroscopy (1D and 2D) and high‐resolution mass spectrometry (HRMS). The structure and abnormal coordination modes of the complex are further confirmed with the help of single‐crystal X‐ray diffraction. The studies revealed the abnormal coordination mode in LPdBr where C5 carbon of the imidazolium ring participates in bonding, leaving the C2 position unaffected. The catalytic potential of complex LPdBr was investigated in the Pd‐catalyzed Suzuki‐Miyaura coupling of various aryl/heteroaryl chlorides with different aryl/naphthyl/phenanthryl boronic acids. The catalyst LPdBr successfully activated various less‐activated aryl chloride substrates. LPdBr also exhibited good catalytic activity at 1 mol% Pd loading under microwave irradiation and in green solvent water. The mechanism of the catalytic cycle is investigated and proposed by HRMS.
Facile Construction of Functionalized 4H‐Chromene Scaffolds via Sn(OTf)2‐Catalyzed C−H Functionalization/Cyclization Reaction and Ir‐Catalyzed Direct C−H Amidation
Authors: Qi Hongbo , He Junxia , Yuan Xingyu , Chen Shufeng 
Published: May 2023

AbstractAn efficient strategy for the construction of 4H‐chromene scaffolds from naphthols and conjugated diketones through a sequential Sn(OTf)2‐catalyzed Friedel–Crafts type C−H functionalization/cyclization process has been described. The Ir‐catalyzed C−H amination of these products could also be performed with the assistance of the carbonyl as a weak directing group, which produced a series of amino‐modified 4H‐chromene compounds in good yields.
Ultrasound evaluation of normal rhesus macaque fetal biometry and uteroplacental hemodynamics
Authors: D'Mello Rahul J. , Lo Jamie O. , Hagen Olivia L. , Castro Jenna N. , Graham Jason A. , Frias Antonio E. , Roberts Victoria H. J. 
Published: May 2023

AbstractNonhuman primates are important preclinical models for translational, reproductive, and developmental science. Clinical evaluation of human fetal development is performed using standard sonographic‐derived fetal biometry, assessments of amniotic fluid, and uteroplacental hemodynamics. These noninvasive in utero measurements provide important information regarding fetal growth and pregnancy well‐being. Abnormalities in fetal growth, amniotic fluid volume, or placental vascular function are associated with placental insufficiency and adverse perinatal outcomes including stillbirth. The fetal biometric parameters most commonly assessed are biparietal diameter, head circumference, abdominal circumference, and femur diaphysis length. Evaluation of amniotic fluid volume includes measuring the fluid in four quadrants of the uterus to generate an Amniotic Fluid Index. Measures of uteroplacental hemodynamics typically include doppler assessment of the umbilical artery and ductus venosus, but can also include interrogation of the uterine artery and umbilical vein. In this study, we compile prenatal ultrasound data of fetal biometry, amniotic fluid measurements, and uteroplacental hemodynamics obtained from pregnancy studies conducted at the Oregon National Primate Research Center. The data included are from control unperturbed pregnant animals who have not undergone in utero experimental manipulations. This is the first report of comprehensive sonographic measurements following standardized clinical obstetric protocols utilized in rhesus macaques. The outcome is a large, prenatal ultrasound resource to be used by laboratory animal researchers in future nonhuman primate pregnancy studies for antenatal assessment.
Rearrangements of Internally‐bridged Octaphyrin(1.1.1.1.1.1.1.1)s to Porphyrin Dimers
Authors: Nakai Akito , Tanaka Takayuki , Osuka Atsuhiro 
Published: May 2023

AbstractInternally‐bridged octaphyrin(1.1.1.1.1.1.1.1) underwent a rearrangement to meso‐meso linked porphyrin dimer as a new metamorphosis. Extensive examination suggests that hydride‐addition is a key step for the rearrangements to afford thermodynamically more stable porphyrin framework. Further, β‐tetrabromo[36]octaphyrin was transformed to meso‐meso, β‐β, β‐β triply linked porphyrin dimer via a similar mechanism combined with Pd‐mediated reductive homocoupling.
Noncovalent Modulation of Chemoselectivity in the Gas Phase Leads to a Switchover in Reaction Type from Heterolytic to Homolytic to Electrocyclic Cleavage
Authors: Moorthy Suresh , Lambert Hugues , Mohan Neetha , Schwarzlose Thomas , Nau Werner M. , Kalenius Elina , Lee Tung‐Chun 
Published: May 2023

AbstractIn the gas phase, thermal activation of supramolecular assemblies such as host–guest complexes leads commonly to noncovalent dissociation into the individual components. Chemical reactions, for example of encapsulated guest molecules, are only found in exceptional cases. As observed by mass spectrometry, when 1‐amino‐methyl‐2,3‐diazabicyclo[2.2.2]oct‐2‐ene (DBOA) is complexed by the macrocycle β‐cyclodextrin, its protonated complex undergoes collision‐induced dissociation into its components, the conventional reaction pathway. Inside the macrocyclic cavity of cucurbit[7]uril (CB7), a competitive chemical reaction of monoprotonated DBOA takes place upon thermal activation, namely a stepwise homolytic covalent bond cleavage with the elimination of N2, while the doubly protonated CB7⋅DBOA complex undergoes an inner‐phase elimination of ethylene, a concerted, electrocyclic ring‐opening reaction. These chemical reaction pathways stand in contrast to the gas‐phase chemistry of uncomplexed monoprotonated DBOA, for which an elimination of NH3 predominates upon collision‐induced activation, as a heterolytic bond cleavage reaction. The combined results, which can be rationalized in terms of organic‐chemical reaction mechanisms and density‐function theoretical calculations, demonstrate that chemical reactions in the gas phase can be steered chemoselectively through noncovalent interactions.
Appealing sheath‐core spun high‐performance composite carbon molecular sieve membranes
Authors: Cao Yuhe , Liu Zhongyun , Qiu Wulin , Koros William J. 
Published: May 2023

AbstractCarbon molecular sieve (CMS) membranes are attractive candidates to meet requirements for challenging gas separations. The added ability to maintain such intrinsic properties in an asymmetric morphology with a structure that we term a “Pseudo Wheel+Hub & Spoke” asymmetric form offers new opportunities. For CMS membrane, specifically, the structure provides both selective layer support and low flow resistance even for high feed pressures and fluxes in CO2 removal from natural gas. This capability is unavailable to even rigid glassy polymers due to the much higher modulus of CMS materials. Combining precursor asymmetric hollow fiber formation and optimized pyrolysis creates a defect free CMS proof‐of‐concept membrane for this application. Facile formation of the sheath‐core spun precursor with a 6FDA‐DAM sheath and Matrimid® core also avoids the need to seal defects before or after the carbonization of the precursors. The composite CMS membrane shows CO2/CH4 (50 : 50) mixed gas feed with an attractive CO2/CH4 selectivity of 64.3 and CO2 permeance of 232 GPU at 35 °C. A key additional benefit of the approach is reduction in use of the more costly high performance 6FDA‐DAM in a composite sheath‐core CMS membrane with the “Pseudo Wheel+Hub & Spoke” structure.
Lewis‐Säure‐katalysierte formale (3+2)‐Cycloaddition von Bicyclo[1.1.0]butanen mit Ketenen
Authors: Radhoff Niklas , Daniliuc Constantin G. , Studer Armido 
Published: May 2023

AbstractDesign, Synthese und Anwendung von Benzolbioisosteren haben in den letzten 20 Jahren viel Aufmerksamkeit erfahren. In jüngster Zeit haben sich Bicyclo[2.1.1]hexane als äußerst attraktive Bioisostere für ortho‐ und meta‐substituierte Benzole erwiesen. In diesem Artikel beschreiben wir eine milde, skalierbare und übergangsmetallfreie Methode zur Herstellung von hochsubstituierten Bicyclo[2.1.1]hexanen über eine Lewis‐Säure‐katalysierte (3+2)‐Cycloaddition von Bicyclo[1.1.0]butanketonen mit disubstituierten Ketenen. Die Reaktion zeigt eine hohe Toleranz gegenüber funktionellen Gruppen, wie die erfolgreiche Herstellung verschiedener 3‐Alkyl‐3‐Aryl‐ sowie 3,3‐Bisalkyl‐Bicyclo[2.1.1]hexan‐2‐onen belegt (26 Beispiele, bis zu 89 % Ausbeute). Die Folgechemie an der exozyklischen Ketonfunktion wird ebenfalls demonstriert.
Ru(bpy)32+‐Enabled Cell‐Surface Photocatalytic Proximity Labeling toward More Efficient Capture of Physically Interacting Cells
Authors: Qiu Shuang , Li Wannan , Deng Tao , Bi Angzhi , Yang Yang , Jiang Xi , Li Jie P. 
Published: May 2023

AbstractIntercellular proximity labeling has emerged as a promising approach to enable the study of cell‐cell interactions (CCIs), but the efficiency of current platforms is limited. Here, we use Ru(bpy)32+ to construct an efficient photocatalytic proximity labeling (PPL) system on the cell surface that allows the highly discriminative CCI detection with spatiotemporal resolution. Through the mechanism study and quantitative characterization on living cells, we demonstrate that the singlet‐oxygen (1O2) mechanism is more efficient and specific than the single electron transfer (SET) mechanism in Ru‐mediated PPL. Ru(bpy)32+ catalysts with different cell‐anchoring moieties are prepared to facilitate the catalyst loading on primary cells. Finally, based on this system, we develop a “live” T cell receptor (TCR) multimer with TCR‐T cells that could sensitively identify and discriminate cells presenting antigens of different affinity, providing a powerful tool to better understand the heterogeneity of antigen presenting cells.
Palladium‐Catalyzed Hydrosilylation of Unactivated Alkenes and Conjugated Dienes with Tertiary Silanes Controlled by Hemilabile Hybrid P,O Ligand
Authors: Seo Sanghyup , Jung Joonho , Kim Hyunwoo 
Published: May 2023

AbstractNovel P,O‐type ligands, N‐disulfonyl bicyclic bridgehead phosphorus triamides, were synthesized and utilized in Pd‐catalyzed hydrosilylation involving tertiary silanes, unactivated alkenes, and conjugated dienes. The ligand displayed a remarkable level of reactivity for alkene hydrosilylation with tertiary silanes and its use resulted in a significant improvement in the regioselectivity of diene hydrosilylation towards 1,2‐hydrosilylation. X‐ray crystallographic analysis confirmed the bidentate nature of the ligand, with coordination of phosphorus and oxygen. Control experiments provided evidence for the formation of Pd0 species and the reversibility of Pd−H insertion in the reaction mechanism. Density functional theory (DFT) computations supported the importance of the hemilabile P,O ligand in stabilizing both the rate‐determining transition state of Pd−H insertion and the transition state of reductive elimination that determines the regioselectivity.
Lewis Acid Catalyzed Formal (3+2)‐Cycloaddition of Bicyclo[1.1.0]butanes with Ketenes
Authors: Radhoff Niklas , Daniliuc Constantin G. , Studer Armido 
Published: May 2023

AbstractDesign, synthesis and application of benzene bioisosteres have attracted a lot of attention in the past 20 years. Recently, bicyclo[2.1.1]hexanes have emerged as highly attractive bioisosteres for ortho‐ and meta‐substituted benzenes. Herein we report a mild, scalable and transition‐metal‐free protocol for the construction of highly substituted bicyclo[2.1.1]hexan‐2‐ones through Lewis acid catalyzed (3+2)‐cycloaddition of bicyclo[1.1.0]‐butane ketones with disubstituted ketenes. The reaction shows high functional group tolerance as documented by the successful preparation of various 3‐alkyl‐3‐aryl as well as 3,3‐bisalkyl bicyclo[2.1.1]hexan‐2‐ones (26 examples, up to 89 % yield). Postfunctionalization of the exocyclic ketone moiety is also demonstrated.
Gold‐Catalyzed Amine Cascade Addition to Diyne‐Ene: Enantioselective Synthesis of 1,2‐Dihydropyridines
Authors: Wei Jingwen , Xing Yangyang , Ye Xiaohan , Nguyen Bao , Wojtas Lukasz , Hong Xin , Shi Xiaodong 
Published: May 2023

AbstractWith the well‐documented chemical and biological applications, piperidine and pyridine are among the most important N‐heterocycles, and a new synthetic strategy, especially one with an alternative bond‐forming design, is of general interest. Using the gold‐catalyzed intermolecular condensation of amine and diyne‐ene, we report herein the first example of enantioselective 1,2‐dihydropyridine synthesis through a formal [3+2+1] fashion (up to 95 % yield, up to 99 % e.e.).
Isothermal curing analysis and properties of ultra heat‐resistant polyimide composites by DMA method
Authors: Xiong Xuhai , Li Wenqiang , Ren Rong , Wang Jing 
Published: May 2023

AbstractThe isothermal curing process of T700 carbon fiber/P450 polyimide prepreg is characterized by dynamic mechanical analysis method and the gelation points are analyzed by torsional braid analysis theory. The growth mechanisms of the mechanical property at different constant temperatures are investigated by the relative mechanical growth rate of storage modulus and the curing kinetics models are established. The theories of Flory and Hsich are used to calculate the activation energy during the curing reaction of prepreg. The results indicates that the gelation times which are detected by the method of torsional braid analysis at 300, 310, 330, and 350°C were 293.7, 213.8, 104.1, and 45.4 min, respectively. The activation energies of curing reaction are calculated by Flory theory and Hsich theory, they are 112.35 and 119.96 kJ/mol, respectively. The feasibly of curing system 300°C × 4 h + 330°C × 2 h + 350°C × 2 h + 370°C × 2 h is verified by the mechanical properties and the heat resistance of polyimide composite.
Experimental study of the topological flow transformations in an aerial vortex bioreactor with a floating washer
Authors: Naumov Igor V. , Gevorgiz Ruslan G. , Skripkin Sergey G. , Tintulova Maria V. , Tsoi Mikhail A. , Sharifullin Bulat R. 
Published: May 2023

AbstractBackgroundResearch into the flow structure in an aerial vortex bioreactor is relevant for developing the methods for growing cell cultures. Determining the optimal cultivation condition for a certain process is especially important in the case when such parameters of the medium as density and viscosity significantly change with the culture growth in the bioreactor.Methods and resultsThe research of the flow dynamic was carried out in an 8.5 L universal aerial vortex bioreactor, with a washer freely floating on its surface and stabilizing the motion of the working fluid. The regularities of the vortex motion of the culture medium have been determined by Particle Image Velocimetry depending on its volume and the intensity of rotation of the activator, generating vortex motion in the air.ConclusionThe observed vortex structure and its dynamics at increasing flow swirl intensity are established to coincide with the structure of a confined vortex flow in a cylindrical container with no washer for both single and two‐fluid configurations. This novel methodology of the flow optimization shows that an ascending swirling jet forms in the vicinity of the bioreactor axis, and a bubble‐like vortex breakdown forms in the axial region.
Establishment and application of a survival rate graph model based on biomarkers and imaging indexes after primary hepatocellular carcinoma resection
Authors: Xu Yue , Yao Xiaoqin , Li Jinmei , Zhang Guoyuan , Luo Guangcheng , Wang Qiang 
Published: May 2023

AbstractBackgroundPrimary liver cancer (PLC) is a highly malignant disease. This study developed an effective and convenient tool to evaluate survival times of patients after hepatectomy, which can provide a reference point for clinical decisions.MethodsClinical and laboratory data of 243 patients with PLC after hepatectomy were collected. Univariate cox regression analysis, Lasso regression analysis and multivariate cox regression analysis were used to determine the best prediction index. Multivariate cox regression analysis was used to construct a survival prediction model. A receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis (DCA) were used to verify the model. The patients in this model were divided into was divided into high‐risk and low‐risk groups according to the optimal cut‐off value of the ROC curve for different prognostic years. Kaplan–Meier survival analysis and log‐rank test were used to analyse the survival differences between the two groups.ResultsTumour size, portal vein thrombosis, distant metastasis, alpha‐fetoprotein and protein induced by vitamin K absence or antagonist‐II levels were independent risk factors for overall survival (OS) after PLC surgery. The area under the concentration‐time curve for 2‐, 3‐ and 4‐year survival of patients was 0.710, 0.825 and 0.919, respectively, with a good calibration of the Hosmer–Lemeshow test (p > 0.05) and net benefit. The mortality rates in patients with 2, 3 and 4 years of survival were 70.59%, 67.83% and 66.67% for the high‐risk group and 21.84%, 22.50% and 22.67% for the low‐risk group, respectively. The mortality rate of the high‐risk group was significantly higher than that of the low‐risk group (p < 0.05).ConclusionThe OS model of prognosis after PLC surgery constructed in this study can be used to predict the 2‐, 3‐ and 4‐year survival prognoses of patients, and patients with different prognosis years can be re‐stratified so that they achieve more accurate and personalised assessment, thereby providing a reference point for clinical decision‐making.
Extended Scope and Understanding of Zinc‐Dependent Alcohol Dehydrogenases for Reduction of Cyclic α‐Diketones
Authors: Stark Frances , Hoffmann Aaron , Ihle Nadine , Loderer Christoph , Ansorge‐Schumacher Marion B. 
Published: May 2023

AbstractAlcohol dehydrogenases (ADH) are important tools for generating chiral α‐hydroxyketones. Previously, only the ADH of Thauera aromatica was known to convert cyclic α‐diketones with appropriate preference. Here, we extend the spectrum of suitable enzymes by three alcohol dehydrogenases from Citrifermentans bemidjiense (CibADH), Deferrisoma camini (DecADH), and Thauera phenylacetica (ThpADH). Of these, DecADH is characterized by very high thermostability; CibADH and ThpADH convert α‐halogenated cyclohexanones with increased activity. Otherwise, however, the substrate spectrum of all four ADHs is highly conserved. Structural considerations led to the conclusion that conversion of diketones requires not only the expansion of the active site into a large binding pocket, but also the circumferential modification of almost all amino acid residues that form the first shell of the binding pocket. The constellation appears to be overall highly specific for the relative positioning of the carbonyl functions and the size of the C‐ring.
[2+4] Cycloaddition Product of an Amidinate Substituted Dialumene with Toluene
Authors: Kumar Arun , Yadav Komal , Graw Nico , Pandey Madhusudan K. , Herbst‐Irmer Regine , Lourderaj Upakarasamy , Stalke Dietmar , Roesky Herbert W. 
Published: May 2023

AbstractReduction of LAlI2(L=PhC(NiPr2C6H3)2) with two equivalents of KC8in toluene affords the [2+4]cycloaddition product of a dialumene with toluene. The mechanism for the formation of product complex was investigated using density functional theory (DFT) methods.