bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cerebral oxygen metabolic stress is increased in children with sickle cell anemia compared to anemic controls
Authors: Fields Melanie E. , Mirro Amy E. , Binkley Michael M. , Guilliams Kristin P. , Lewis Josiah B. , Fellah Slim , Chen Yasheng , Hulbert Monica L. , An Hongyu , Ford Andria L. , Lee Jin‐Moo 
Published: February 2022

AbstractPatients with sickle cell anemia (SCA) experience cerebral metabolic stress with an increase in oxygen extraction fraction (OEF) to compensate for reduced oxygen carrying capacity due to anemia. It remains unclear if anemia alone drives this metabolic stress. Using MRI, we collected voxel‐wise OEF measurements to test our hypothesis that OEF would be elevated in anemic controls without SCA (AC) compared to healthy controls (HC), but OEF would be even higher in SCA compared to AC. Brain MRIs (N = 159) were obtained in 120 participants (34 HC, 27 AC, 59 SCA). While hemoglobin was lower in AC versus HC (p < 0.001), hemoglobin was not different between AC and SCA cohorts (p = 0.459). Whole brain OEF was higher in AC compared to HC (p < 0.001), but lower compared to SCA (p = 0.001). Whole brain OEF remained significantly higher in SCA compared to HC (p = 0.001) while there was no longer a difference between AC versus HC (p = 0.935) in a multivariate model controlling for age and hemoglobin. OEF peaked within the border zone regions of the brain in both SCA and AC cohorts, but the volume of white matter with regionally elevated OEF in AC was smaller (1.8%) than SCA (58.0%). While infarcts colocalized within regions of elevated OEF, more SCA participants had infarcts than AC (p < 0.001). We conclude that children with SCA experience elevated OEF compared to AC and HC after controlling for the impact of anemia, suggesting that there are other pathophysiologic factors besides anemia contributing to cerebral metabolic stress in children with SCA.
Neanderthal child's occipital from Baume Moula‐Guercy (Soyons, Ardèche, France)
Authors: Richards Gary D. , Jabbour Rebecca S. , Guipert Gaspard , Defleur Alban 
Published: February 2022

AbstractObjectivesThis article provides an ontogenetically based comparative description of two immature occipital fragments from Baume Moula‐Guercy (MIS 5e) and examines their affinities to European and Middle Eastern Middle‐to‐Late Pleistocene (≈MIS 14–MIS ≈ 1) Homo.Materials and methodsDescription of the M‐S‐41 and M‐S‐61 occipital fragments (≈6–8 years) is based on observations of original fossils, casts, CT scans, literature descriptions, and virtual ectocranial and endocranial reconstructions. Our ontogenetically based sample represents a Preneanderthal‐Neanderthal group and a Homo sapiens group. These groups are subdivided into (1) Preneanderthals (≈MIS 14–9), Early Neanderthals (MIS 7–5e), and Late Neanderthals (MIS 5d‐3), and (2) Middle (MIS 5), Upper (MIS 3–1), and Late (MIS ≈ 1) Paleolithic H. sapiens. Measurements and developmental age determinations follow standard techniques.ResultsBased on the M‐S‐41/M‐S‐61 composite, the strongly convex upper occipital scale flattens into the vertical suprainiac fossa, as in immature Early Neanderthals. A doubled suprainiac fossa expressing a weakly developed bounding torus and pocking of the central region is typical of immature Neanderthals. The transverse torus is thickened medially, lacks significant lateral development, has a laterally placed protuberance, and is concave medially. A linear (triangular) tubercle, as opposed to an external occipital protuberance, is present. An occipital bun is absent.DiscussionThe occipital remains from Moula‐Guercy make a substantial contribution to the record of Neanderthal cranial evolution because immature Early Neanderthal occipitals are rare, fragmentary, and likely represent only two paleodemes (Krapina, La Chaise‐de‐Vouthon). The Moula‐Guercy occipital possesses characteristics well‐established in European Neanderthals by MIS 7, and it is most similar to the occipitals of other Early Neanderthals.
Remote C(sp3)−H Acylation of Amides and Cascade Cyclization via N‐Heterocyclic Carbene Organocatalysis
Authors: Li Qing‐Zhu , Zeng Rong , Fan Yang , Liu Yan‐Qing , Qi Ting , Zhang Xiang , Li Jun‐Long 
Published: February 2022

AbstractThe direct functionalization of inert C(sp3)−H bonds under environmentally benign catalytic conditions remains a challenging task in synthetic chemistry. Here, we report an organocatalytic remote C(sp3)−H acylation of amides and cascade cyclization through a radical‐mediated 1,5‐hydrogen atom transfer mechanism using N‐heterocyclic carbene as the catalyst. Notably, a diversity of nitrogen‐containing substrates, including simple linear aliphatic carbamates and ortho‐alkyl benzamides, can be successfully applied to this organocatalytic system. With the established protocol, over 120 examples of functionalized δ‐amino ketones and isoquinolinones with diverse substituents were easily synthesized in up to 99 % yield under mild conditions. The robustness and generality of the organocatalytic strategy were further highlighted by the successful acylation of unactivated C(sp3)−H bonds and late‐stage modification of pharmaceutical molecules. Then, the asymmetric control of the radical reaction was attempted and proven feasible by using a newly designed chiral thiazolium catalyst, and moderate enantioselectivity was obtained at the current stage. Preliminary mechanistic investigations including several control reactions, KIE experiments, and computational studies shed light on the organocatalytic radical reaction mechanism.
Palladium(II)‐Catalyzed Selective Arylation of Tertiary C−H Bonds of Cyclobutylmethyl Ketones Using Transient Directing Groups
Authors: Cheng Jin‐Tang , Xiao Li‐Jun , Qian Shao‐Qun , Zhuang Zhe , Liu An , Yu Jin‐Quan 
Published: February 2022

AbstractWe report the first example of selective PdII‐catalyzed tertiary C−H activation of cyclobutylmethyl ketones using a transient directing group. An electron‐deficient 2‐pyridone ligand was identified as the optimal external ligand to enable tertiary C−H activation. A variety of cyclobutylmethyl ketones bearing quaternary carbon centers was readily accessed without preinstalling internal directing groups in up to 81 % yield and >95 : 5 regioisomeric ratios of tertiary C−H arylation to β‐methylene (β‐methyl) or γ‐C−H arylation.
Reversible One‐ to Two‐ to Three‐Dimensional Transformation in CuII Coordination Polymer
Authors: Jing Yao , Yoshida Yukihiro , Huang Pingping , Kitagawa Hiroshi 
Published: February 2022

AbstractA reversible transformation between 1D, 2D, and 3D is demonstrated for the first time in coordination polymers comprising CuII ions and bidentate terephthalate (BDC2−). 1D uniform chains were reversibly transformed into 2D layers with the construction of Cu‐paddlewheels by eliminating water molecules. 2D/3D reversible transformation was achieved by removing/rebinding N,N‐dimethylformamide coordinated to the paddlewheels. These dimensional transformations significantly changed chemical and physical properties such as gas sorption and magnetism. Although the uptake in open‐framework 1D and 2D Cu‐BDC was insignificant, pronounced absorption was observed for 3D Cu‐BDC. Drastic difference in magnetic behavior is consistent with their coordination structures; uniform 1D chain of CuII in 1D Cu‐BDC and 2D sheet based on CuII‐paddlewheel dimers in 2D Cu‐BDC. Ferromagnetic behavior observed in air‐exposed 3D Cu‐BDC is attributed to the 3D structure formed by the connection of 2D sheets.
Enantioselective Synthesis of (−)‐10‐Hydroxyacutuminine
Authors: Grünenfelder Denise C. , Navarro Raul , Wang Haoxuan , Fastuca Nicholas J. , Butler John R. , Reisman Sarah E. 
Published: February 2022

AbstractAn enantioselective synthesis of (−)‐10‐hydroxyacutuminine is reported. Central to our strategy is a photochemical [2+2] cycloaddition that forges two of the quaternary stereocenters present in the acutumine alkaloids. A subsequent retro‐aldol/Dieckmann sequence furnishes the spirocyclic cyclopentenone. Efforts to chlorinate the acutumine scaffold at C10 under heterolytic or radical deoxychlorination conditions led to the synthesis of an unexpected cyclopropane‐containing pentacycle.
Tuning Bulk O2 and Nonbonding Oxygen State for Reversible Anionic Redox Chemistry in P2‐Layered Cathodes
Authors: Li Zhenrui , Kong Weijin , Yu Yang , Zhang Jicheng , Wong Deniz , Xu Zijian , Chen Zhenhua , Schulz Christian , Bartkowiak Maciej , Liu Xiangfeng 
Published: February 2022

AbstractImproving the reversibility of oxygen redox is quite significant for layered oxides cathodes in sodium‐ion batteries. Herein, we for the first time simultaneously tune bulk O2 and nonbonding oxygen state for reversible oxygen redox chemistry in P2‐Na0.67Mn0.5Fe0.5O2 through a synergy of Li2TiO3 coating and Li/Ti co‐doping. O2− is oxidized to molecular O2 and peroxide (O2)n− (n<2) during charging. Molecular O2 derived from transition metal (TM) migration is related to the superstructure ordering induced by Li doping. The synergy mechanism of Li2TiO3 coating and Li/Ti co‐doping on the two O‐redox modes is revealed. Firstly, Li2TiO3 coating restrains the surface O2 and inhibits O2 loss. Secondly, nonbonding Li−O−Na enhances the reversibility of O2−→(O2)n−. Thirdly, Ti doping strengthens the TM−O bond which fixes lattice oxygen. The cationic redox reversibility is also enhanced by Li/Ti co‐doping. The proposed insights into the oxygen redox reversibility are insightful for other oxide cathodes.
Record Aluminum Molecular Rings for Optical Limiting and Nonlinear Optics
Authors: Li Yuan , Zheng Chan , Wang San‐Tai , Liu Ya‐Jie , Fang Wei‐Hui , Zhang Jian 
Published: February 2022

AbstractCrystalline cluster materials, a class of functional motif aggregations, provide a great opportunity for tuning the properties stemming from the flexible and accurate variation of inorganic and organic compositions. In this study, we demonstrate the effects of functional ligand and ring size regulation on the structures and third‐order nonlinear optical (NLO) properties. Revealed by the single‐crystal X‐ray analysis results, aluminum molecular ring expansion is achieved by 2×9 and 3×6 strategies. In terms of the given organic shells, we further tuned the aluminum molecular ring sizes from 3.0 nm to 1.7 nm. The picosecond Z‐scan measurements results revealed that the third‐order NLO performances do not only depend on the general conjugate interactions but are also related to hydrogen bonding, polarizability, and ring sizes. The large nonlinear absorption coefficient and onset prove that the observed samples are promising candidates for the field of nonlinear optics.
Single‐Vesicle Electrochemistry Reveals Sex Difference in Vesicular Storage and Release of Catecholamine
Authors: Yue Qingwei , Wang Kai , Guan Ming , Zhao Zhenwen , Li Xianchan , Yu Ping , Mao Lanqun 
Published: February 2022

AbstractQuantitative measurements of sex difference in vesicle chemistry (i.e., chemical storage and release) at the single‐vesicle level are essential to understand sex differences in cognitive behaviors; however, such measurements are very challenging to conventional analytical methods. By using single‐vesicle electrochemistry, we find the duration of single exocytotic events of chromaffin cells prepared from male rats is statistically longer than that from female rats, leading to more neurotransmitter released in the male group. Further analysis reveals that a higher percentage of vesicles in the female group release part of the neurotransmitter, i.e., partial release, during exocytosis than that in male group. This sex dimorphism in neurotransmitter release in exocytosis might relate to the sex difference in the expression of voltage‐dependent calcium channels and membrane lipid composition. Our finding offers the first experimental evidence that sex dimorphism even exists in vesicle chemistry, providing a brand new viewpoint for understanding the sex dimorphism in exocytosis.
Anti‐cooperative Self‐Assembly with Maintained Emission Regulated by Conformational and Steric Effects
Authors: Helmers Ingo , Hossain Muhammad Saddam , Bäumer Nils , Wesarg Paul , Soberats Bartolome , Shimizu Linda S. , Fernández Gustavo 
Published: February 2022

AbstractHerein, we present a strategy to enable a maintained emissive behavior in the self‐assembled state by enforcing an anti‐cooperative self‐assembly involving weak intermolecular dye interactions. To achieve this goal, we designed a conformationally flexible monomer unit 1 with a central 1,3‐substituted (diphenyl)urea hydrogen bonding synthon that is tethered to two BODIPY dyes featuring sterically bulky trialkoxybenzene substituents at the meso‐position. The competition between attractive forces (H‐bonding and aromatic interactions) and destabilizing effects (steric and competing conformational effects) limits the assembly, halting the supramolecular growth at the stage of small oligomers. Given the presence of weak dye–dye interactions, the emission properties of molecularly dissolved 1 are negligibly affected upon aggregation. Our findings contribute to broadening the scope of emissive supramolecular assemblies and controlled supramolecular polymerization.
Computational analysis of cross‐flow of power‐law fluids through a periodic square array of circular cylinders
Authors: Bharti Ram Prakash , Ram Ram Pravesh , Dhiman Amit Kumar 
Published: February 2022

AbstractThe steady flow of non‐Newtonian power‐law fluids across a periodic square array of infinitely long circular cylinders is studied numerically using an unstructured finite volume method. The local and global flow characteristics have extensively been explored by the systematic variations of the pertinent dimensionless parameters as follows: fluid volume fraction (ϕf = .70–.99), Reynolds number (Re = 1–40), and power‐law index (n = .4–1.8). Qualitatively, the dense and curved streamlines are seen with the increasing inertial forces and shear‐thinning behavior across all the fluid volume fractions. Further, the pressure coefficient over the surface of periodic cylinders is significantly influenced by the governing parameters and found to be maximum and minimum for the upstream and downstream cylinders, respectively. The individual and total drag coefficients have shown complex dependence on n, ϕf, and Re. For shear‐thinning fluids (n < 1), the pressure drag coefficient dominates over the friction drag coefficient, whereas an opposite response is seen for the shear‐thickening fluids (n > 1) except at Re = 40. Further, both individual and total drag coefficients are observed to increase and decrease in the ranges of ϕf of .70–.90 and .92–.99, respectively, with increasing n. The strong interactions between the periodic cylinders, at smaller ϕf, diminish with a corresponding increase in ϕf. In addition, simple predictive correlations for the pressure, friction, and total drag coefficients have been developed to gain further physical insights into the detailed flow kinematics. Finally, the present findings display a good agreement with the available literature.
Influence of different mixing sequence on UHMW‐EPDM based thermoplastic vulcanizates: Mechanical, rheological and morphological characteristics
Authors: Bhattacharya Asit Baran , Das Mithun , Sreethu T. K. , Maji Purbasha , Naskar Kinsuk 
Published: February 2022

AbstractAn important factor for the preparation of thermoplastic vulcanizates (TPVs) is the mixing sequence or technique as it is controlling the product quality and production rate. The effect of different routes of mixing sequences on the mechanical properties and rheological properties have been studied. Four different types of mixing sequences have been pursued and ultra‐high molecular weight EPDM (UHMW‐EPDM) master batch technique has shown maximum prospect over the melt blending method. Co‐agent master‐batch sample showed optimum balance between TS and %EB over the other master‐batch samples. Melt blending technique shows moderate properties for all cases. Rheological data follows the same trend as observed for the mechanical properties. Crosslink density also found the highest for the co‐agent master‐batch sample and co‐agent/peroxide master‐batch sample over the other two samples. Cryo‐fractured and etched TPV samples were prepared and examined in FE‐SEM. Co‐agent master‐batch sample shows the droplet type morphology. This new type of UHMW‐EPDM based TPV with co‐agent/rubber master‐batch mixing technique leads to superior physico‐mechanical properties over the other mixing techniques. These newly established TPVs can be used as various injection molded parts, esthetic seals/strips and 2K‐molds for the automotive applications.
Differential N‐ and O‐glycosylation signatures of HIV‐1 Gag virus‐like particles and coproduced extracellular vesicles
Authors: Lavado‐García Jesús , Zhang Tao , Cervera Laura , Gòdia Francesc , Wuhrer Manfred 
Published: February 2022

AbstractHuman immunodeficiency virus 1 (HIV‐1) virus‐like particles (VLPs) are nanostructures derived from the self‐assembly and cell budding of Gag polyprotein. Mimicking the native structure of the virus and being noninfectious, they represent promising candidates for the development of new vaccines as they elicit a strong immune response. In addition to this, the bounding membrane can be functionalized with exogenous antigens to target different diseases. Protein glycosylation depends strictly on the production platform and expression system used and the displayed glycosylation patterns may influence downstream processing as well as the immune response. One of the main challenges for the development of Gag VLP production bioprocess is the separation of VLPs and coproduced extracellular vesicles (EVs). In this study, porous graphitized carbon separation method coupled with mass spectrometry was used to characterize the N‐ and O‐ glycosylation profiles of Gag VLPs produced in HEK293 cells. We identified differential glycan signatures between VLPs and EVs that could pave the way for further separation and purification strategies to optimize downstream processing and move forward in VLP‐based vaccine production technology.
Role of histidine decarboxylase gene in the pathogenesis of Tourette syndrome
Authors: Xu Lulu , Zhang Cheng , Zhong Meixiang , Che Fengyuan , Guan Chengcheng , Zheng Xueping , Liu Shiguo 
Published: February 2022

AbstractTourette syndrome (TS) is caused by complex genetic and environmental factors and is characterized by tics. Histidine decarboxylase (HDC) mutation is a rare genetic cause with high penetrance in patients with TS. HDC‐knockout (KO) mice have similar behavioral and neurochemical abnormalities as patients with TS. Therefore, HDC‐KO mice are considered a valuable TS pathophysiological model as it reveals the underlying pathological mechanisms that cannot be obtained from patients with TS, thus advancing the development of treatment strategies for TS and other tic disorders. This review summarizes some of the recent research hotspots and progress in HDC‐KO mice, aiming to deepen our understanding of brain mechanisms relevant to TS. Furthermore, we encapsulate the possible brain nerve cell changes in HDC‐KO mice and their potential roles in TS to provide multiple directions for the future research on tics.
Immobilization of the Aspartate Ammonia‐Lyase from Pseudomonas fluorescens R124 on Magnetic Nanoparticles: Characterization and Kinetics
Authors: Csuka Pál , Molnár Zsófia , Tóth Veronika , Imarah Ali Obaid , Balogh‐Weiser Diána , Vértessy Beáta G. , Poppe László 
Published: February 2022

AbstractAspartate ammonia‐lyases (AALs) catalyze the non‐oxidative elimination of ammonia from l‐aspartate to give fumarate and ammonia. In this work the AAL coding gene from Pseudomonas fluorescens R124 was identified, isolated, and cloned into the pET‐15b expression vector and expressed in E. coli. The purified enzyme (PfAAL) showed optimal activity at pH 8.8, Michaelis‐Menten kinetics in the ammonia elimination from l‐aspartate, and no strong dependence on divalent metal ions for its activity. The purified PfAAL was covalently immobilized on epoxy‐functionalized magnetic nanoparticles (MNP), and effective kinetics of the immobilized PfAAL‐MNP was compared to the native solution form. Glycerol addition significantly enhanced the storability of PfAAL‐MNP. Inhibiting effect of the growing viscosity (modulated by addition of glycerol or glucose) on the enzymatic activity was observed for the native and immobilized form of PfAAL, as previously described for other free enzymes. The storage stability and recyclability of PfAAL‐MNP is promising for further biocatalytic applications.
Mapping the Conformational Landscape of the Neutral Network of RNA Sequences That Connect Two Functional Distinctly Different Ribozymes
Authors: Knezic Bozana , Keyhani‐Goldau Sara , Schwalbe Harald 
Published: February 2022

AbstractDuring evolution of an RNA world, the development of enzymatic function was essential. Such enzymatic function was linked to RNA sequences capable of adopting specific RNA folds that possess catalytic pockets to promote catalysis. Within this primordial RNA world, initially evolved self‐replicating ribozymes presumably mutated to ribozymes with new functions. Schultes and Bartel (Science 2000, 289, 448–452) investigated such conversion from one ribozyme to a new ribozyme with distinctly different catalytic functions. Within a neutral network that linked these two prototype ribozymes, a single RNA chain could be identified that exhibited both enzymatic functions. As commented by Schultes and Bartel, this system possessing one sequence with two enzymatic functions serves as a paradigm for an evolutionary system that allows neutral drifts by stepwise mutation from one ribozyme into a different ribozyme without loss of intermittent function. Here, we investigated this complex functional diversification of ancestral ribozymes by analyzing several RNA sequences within this neutral network between two ribozymes with class III ligase activity and with self‐cleavage reactivity. We utilized rapid RNA sample preparation for NMR spectroscopic studies together with SHAPE analysis and in‐line probing to characterize secondary structure changes within the neutral network. Our investigations allowed delineation of the secondary structure space and by comparison with the previously determined catalytic function allowed correlation of the structure‐function relation of ribozyme function in this neutral network.