bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homeobox genes for embryo implantation: From mouse to human
Authors: He Bo , Ni Zhang‐li , Kong Shuang‐bo , Lu Jin‐hua , Wang Hai‐bin 
Published: April 2018

AbstractThe proper development of uterus to a state of receptivity and the attainment of implantation competency for blastocyst are 2 indispensable aspects for implantation, which is considered to be a critical event for successful pregnancy. Like many developmental processes, a large number of transcription factors, such as homeobox genes, have been shown to orchestrate this complicated but highly organized physiological process during implantation. In this review, we focus on progress in studies of the role of homeobox genes, especially the Hox and Msx gene families, during implantation, together with subsequent development of post‐implantation uterus and related reproductive defects in both mouse models and humans, that have led to better understanding of how implantation is precisely regulated and provide new insights into infertility.
Dhcr24 activates the PI3K/Akt/HKII pathway and protects against dilated cardiomyopathy in mice
Authors: Dong Wei , Guan Fei‐fei , Zhang Xu , Gao Shan , Liu Ning , Chen Wei , Zhang Lian‐feng , Lu Dan 
Published: April 2018

AbstractBackground24‐dehydrocholesterol reductase (Dhcr24) catalyzes the last step of cholesterol biosynthesis, which is required for normal development and anti‐apoptotic activities of tissues. We found that Dhcr24 expression decreased in the cTnTR141W dilated cardiomyopathy (DCM) transgenic mice. Therefore, we tested whether rescued expression of Dhcr24 could prevent the development of DCM and its possible mechanism.MethodsHeart tissue specific transgenic overexpression mice of Dhcr24 was generated, then was crossed to cTnTR141W mouse to obtain the double transgenic mouse (DTG). The phenotypes were demonstrated by the survival, cardiac geometry and function analysis, as well as microstructural and ultrastructural observations based on echocardiography and histology examination. The pathway and apoptosis were analysed by western blotting and TUNEL assay in vivo and in vitro.ResultsWe find that Dhcr24 decreased in hearts tissues of cTnTR141W and LMNAE82K DCM mice. The transgenic overexpression of Dhcr24 significantly improves DCM phenotypes in cTnTR141W mice, and activates PI3K/Akt/HKII pathway, followed by a reduction of the translocation of Bax and release of cytochrome c, caspase‐9 and caspase‐3 activation and myocyte apoptosis. Knockdown the expression of Dhcr24 reduces the activation of PI3K/Akt/HKII pathway and inhibition of the mitochondrial‐dependent apoptosis. The anti‐apoptotic effect of Dhcr24 could be completely removed by the inhibition of PI3K pathway and partly removed by the HKII inhibitor in H9c2 cell line.ConclusionCompensatory expression of Dhcr24 protect against DCM through activated PI3K/Akt/HKII pathway and reduce Bax translocation. This is the first investigation for the molecular mechanism of Dhcr24 participate in development of DCM.
Mouse models of porcine circovirus 2 infection
Authors: Ouyang Ting , Liu Xiao‐hui , Ouyang Hong‐sheng , Ren Lin‐zhu 
Published: April 2018

AbstractPCV2 is considered the main pathogen of porcine circovirus diseases and porcine circovirus‐associated diseases (PCVD/PCVAD). However, the exact mechanism underlying PCVD/PCVAD is currently unknown. Mouse models of PCV2 are valuable experimental tools that can shed light on the pathogenesis of infection and will enable the evaluation of antiviral agents and vaccine candidates. In this review, we discuss the current state of knowledge of mouse models used in PCV2 research that has been performed to date, highlighting their strengths and limitations, as well as prospects for future PCV2 studies.
Instant Locking of Molecular Ordering in Liquid Crystal Elastomers by Oxygen‐Mediated Thiol–Acrylate Click Reactions
Authors: Xia Yu , Zhang Xinyue , Yang Shu 
Published: April 2018

AbstractLiquid crystal elastomers (LCEs) with intrinsic anisotropic strains are reversible shape‐memory polymers of interest in sensor, actuator, and soft robotics applications. Rapid gelation of LCEs is required to fix molecular ordering within the elastomer network, which is essential for directed shape transformation. A highly efficient photo‐cross‐linking chemistry, based on two‐step oxygen‐mediated thiol–acrylate click reactions, allows for nearly instant gelation of the main‐chain LCE network upon exposure to UV light. Molecular orientation from the pre‐aligned liquid crystal oligomers can be faithfully transferred to the LCE films, allowing for preprogrammed shape morphing from two to three dimensions by origami‐ (folding‐only) and kirigami‐like (folding with cutting) mechanisms. The new LCE chemistry also enables widely tunable physical properties, including nematic‐to‐ isotropic phase‐transition temperatures (TN‐I), glassy transition temperatures (Tg), and mechanical strains, without disrupting the LC ordering.
A Desulfurative Strategy for the Generation of Alkyl Radicals Enabled by Visible‐Light Photoredox Catalysis
Authors: Xue Fei , Wang Falu , Liu Jiazhen , Di Jiamei , Liao Qi , Lu Huifang , Zhu Min , He Liping , He Huan , Zhang Dan , Song Hao , Liu Xiao‐Yu , Qin Yong 
Published: April 2018

AbstractHerein, we present a new desulfurative method for generating primary, secondary, and tertiary alkyl radicals through visible‐light photoredox catalysis. A process that involves the generation of N‐centered radicals from sulfinamide intermediates, followed by subsequent fragmentation, is critical to forming the corresponding alkyl radical species. This strategy has been successfully applied to conjugate addition reactions that features mild reaction conditions, broad substrate scope (>60 examples), and good functional‐group tolerance.
Stereoretentive Reactions at the Anomeric Position: Synthesis of Selenoglycosides
Authors: Zhu Feng , O'Neill Sloane , Rodriguez Jacob , Walczak Maciej A. 
Published: April 2018

AbstractReported is the stereospecific cross‐coupling of anomeric stannanes with symmetrical diselenides, resulting in the synthesis of selenoglycosides with exclusive anomeric control. The reaction proceeds without the need for directing groups and is compatible with free hydroxy groups as demonstrated in the preparation of glycoconjugates derived from mono‐, di‐, and trisaccharides and peptides (35 examples). Given its generality and broad substrate scope, the glycosyl cross‐coupling method presented herein can find use in the synthesis of selenium‐containing glycomimetics and glycoconjugates.
A Nanohelicoidal Nematic Liquid Crystal Formed by a Non‐Linear Duplexed Hexamer
Authors: Mandle Richard J. , Goodby John W. 
Published: April 2018

AbstractThe twist‐bend modulated nematic liquid‐crystal phase exhibits formation of a nanometre‐scale helical pitch in a fluid and spontaneous breaking of mirror symmetry, leading to a quasi‐fluid state composed of chiral domains despite being composed of achiral materials. This phase was only observed for materials with two or more mesogenic units, the manner of attachment between which is always linear. Non‐linear oligomers with a H‐shaped hexamesogen are now found to exhibit both nematic and twist‐bend modulated nematic phases. This shatters the assumption that a linear sequence of mesogenic units is a prerequisite for this phase, and points to this state of matter being exhibited by a wider range of self‐assembling structures than was previously envisaged. These results support the double helix model of the TB phase as opposed to the simple heliconical model. This new class of materials could act as low‐molecular‐weight surrogates for cross‐linked liquid‐crystalline elastomers.
Enantioselective Rhodium‐Catalyzed Dimerization of ω‐Allenyl Carboxylic Acids: Straightforward Synthesis of C2‐Symmetric Macrodiolides
Authors: Steib Philip , Breit Bernhard 
Published: April 2018

AbstractHerein, we report on the first enantioselective and atom‐efficient catalytic one‐step dimerization method to selectively transform ω‐allenyl carboxylic acids into C2‐symmetric 14‐ to 28‐membered bismacrolactones (macrodiolides). This convenient asymmetric access serves as an attractive route towards multiple naturally occuring homodimeric macrocyclic scaffolds and demonstrates excellent efficiency to construct the complex, symmetric core structures. By utilizing a rhodium catalyst with a modified chiral cyclopentylidene‐diop ligand, the desired diolides were obtained in good to high yields, high diastereoselectivity, and excellent enantioselectivity.
Trifluoromethanesulfonic Anhydride as a Low‐Cost and Versatile Trifluoromethylation Reagent
Authors: Ouyang Yao , Xu Xiu‐Hua , Qing Feng‐Ling 
Published: April 2018

AbstractA large number of reagents have been developed for the synthesis of trifluoromethylated compounds. However, an ongoing challenge in trifluoromethylation reaction is the use of less expensive and practical trifluoromethyl sources. We report herein the unprecedented direct trifluoromethylation of (hetero)arenes using trifluoromethanesulfonic anhydride as a radical trifluoromethylation reagent by merging photoredox catalysis and pyridine activation. Furthermore, introduction of both the CF3 and OTf groups of the trifluoromethanesulfonic anhydride into internal alkynes to access tetrasubstituted trifluoromethylated alkenes was achieved. Since trifluoromethanesulfonic anhydride is a low‐cost and abundant chemical, this method provides a cost‐efficient and practical route to trifluoromethylated compounds.
Polycyclic Indoline‐Benzodiazepines through Electrophilic Additions of α‐Imino Carbenes to Tröger Bases
Authors: Bosmani Alessandro , Guarnieri‐Ibáñez Alejandro , Goudedranche Sébastien , Besnard Céline , Lacour Jérôme 
Published: April 2018

AbstractPolycyclic indoline‐benzodiazepines can be accessed through the intermolecular reaction of Tröger bases with N‐sulfonyl‐1,2,3‐triazoles. Under RhII catalysis, α‐imino carbenes are generated and a subsequent cascade of [1,2]‐Stevens, Friedel–Crafts, Grob, and aminal formation reactions yield the polycyclic heterocycles as single isomers (d.r.>49:1, four stereocenters including two bridgehead N atoms). Further ring expansion by insertion of a second α‐imino carbene leads to elaborated polycyclic 9‐membered‐ring triazonanes.
Bottom‐up Synthesis and Self‐Assembly of Copper Clusters into Permanent Excimer Supramolecular Nanostructures
Authors: Santiago‐Gonzalez Beatriz , Monguzzi Angelo , Capitani Chiara , Prato Mirko , Santambrogio Carlo , Meinardi Francesco , Brovelli Sergio 
Published: April 2018

AbstractMetal clusters with appropriate molecular ligands have been shown to be suitable subnanometer building blocks for supramolecular architectures with controlled secondary interactions, providing access to physical regimes not achievable with conventional intermolecular motifs. An example is the excimer photophysics exhibited by individual cluster‐based superstructures produced by top‐down etching of gold nanoparticles. Now, a supramolecular architecture of copper clusters is presented with controlled optical properties and efficient non‐resonant luminescence produced via a novel bottom‐up synthesis using mild green reductants followed by a ligand exchange reaction and spontaneous supramolecular assembly. Spectroscopic experiments confirm the formation of the intercluster network and reveal the permanent nature of their excimer‐like behavior, thus extending the potential impact and applicability of metal cluster superstructures as efficient and stable non‐resonant single‐particle emitters.
Interfacial interactions and properties of natural rubber–silica composites with liquid natural rubber as a compatibilizer and prepared by a wet‐compounding method
Authors: He Fan , Yuan Tianyuan , Li Chaoqun , Sun Long , Liao Shuangquan 
Published: April 2018

ABSTRACTNatural rubber–silica [W(NR–SiO2)] composites were prepared by wet‐compounding technology with liquid natural rubber (LNR) as a compatibilizer. The effects of the LNR content and wet‐compounding technology on the filler dispersion, Payne effect, curing characteristics, mechanical properties, and interfacial interactions were investigated. The results show that the incorporation of LNR promoted vulcanization and decreased the Payne effect of the W(NR–SiO2) composites. With the addition of 5 phr LNR, the remarkable improvements in the mechanical properties of the W(NR–SiO2) vulcanizates were correlated with the improved silica dispersion and strengthened interfacial bonding. Furthermore, the W(NR–SiO2) vulcanizates containing LNR exhibited improvements in both the wet‐skid resistance and rolling‐resistance performance. The interfacial interactions, quantitatively evaluated by the Mooney–Rivlin equation and Lorenz–Park equation on the basis of the rubber elasticity and reinforcement theory, were strengthened in the presence of LNR. Accordingly, an interfacial structural model was proposed to illustrate the improvements in the mechanical properties of the W(NR–SiO2) composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46457.
Formation of G‐wires, bimolecular and tetramolecular quadruplex: Cation‐induced structural polymorphs of G‐rich DNA sequence of human SYTX gene
Authors: Ahmed Saami , Kaushik Mahima , Chaudhary Swati , Kukreti Shrikant 
Published: April 2018

AbstractAn exceptional property of auto‐folding into a range of intra‐ as well as intermolecular quadruplexes by guanine‐rich oligomers (GROs) of promoters, telomeres and various other genomic locations is still one of the most attractive areas of research at present times. The main reason for this attention is due to their established in vivo existence and biological relevance. Herein, the structural status of a 20‐nt long G‐rich sequence with two G5 stretches (SG20) is investigated using various biophysical and biochemical techniques. Bioinformatics analysis suggested the presence of a 17‐nt stretch of this SG20 sequence in the intronic region of human SYTX (Synaptotagmin 10) gene. The SYTX gene helps in sensing out the Ca2+ ion, causing its intake in the pre‐synaptic neuron. A range of various topologies like bimolecular, tetramolecular and guanine‐wires (nano‐wires) was exhibited by the studied sequence, as a function of cations (Na+/K+) concentration. UV‐thermal denaturation, gel electrophoresis, and circular dichroism (CD) spectroscopy showed correlations and established a cation‐dependent structural switch. The G‐wire formation, in the presence of K+, may further be explored for its possible relevance in nano‐biotechnological applications.
Overexpression of HACE1 in gastric cancer inhibits tumor aggressiveness by impeding cell proliferation and migration
Authors: Chen Ying‐ling , Li Dong‐ping , Jiang Hong‐yue , Yang Yang , Xu Li‐li , Zhang Shun‐cai , Gao Hong 
Published: April 2018

AbstractHACE1 E3 ligase was discovered to be down‐regulated in several cancers while its role in regulating tumors was merely understood. This study aimed to explore the specific effect of HACE1 played in gastric tumorigenesis and its potential mechanism. HACE1's expression was found significantly lower in gastric cancer tissues compared with the adjacent normal tissues (P < 0.001). Its protein level in gastric cancer negatively correlated to tumor pathological differentiation (P = 0.019). And in gastric cancer patients with TNM I‐IIIa, those with lower HACE1 protein level had poorer overall survival (P = 0.025). Studies, in vivo and in vitro, showed that overexpressing HACE1 inhibited tumor proliferation and migration, and enhanced cell apoptosis. Besides, ectopic expression of HACE1 down‐regulated the protein level of β‐catenin and inhibited the activity of the Wnt/β‐catenin signaling pathway. All the cellular functions were abolished when we overexpressed inactive HACE1‐deltaHECT. Above all, we demonstrated that HACE1 E3 ligase played a suppressive role in gastric tumorigenesis and inhibited the activity of the Wnt/β‐catenin signaling pathway. Circumventing the decline of HACE1 in early stage of carcinoma may impede the tumorigenesis and malignant process of gastric cancer.
Optogenetics: A Primer for Chemists
Authors: O'Banion Colin P. , Lawrence David S. 
Published: April 2018

AbstractThe field of optogenetics uses genetically encoded, lightresponsive proteins to control physiological processes. This technology has been hailed as the one of the ten big ideas in brain science in the past decade, the breakthrough of the decade, and the method of the year in 2010 and again in 2014. The excitement evidenced by these proclamations is confirmed by a couple of impressive numbers. The term “optogenetics” was coined in 2006. As of December 2017, “optogenetics” is found in the title or abstract of almost 1600 currently funded National Institutes of Health grants. In addition, nearly 600 reviews on optogenetics have appeared since 2006, which averages out to approximately one review per week! However, in spite of these impressive numbers, the potential applications and implications of optogenetics are not even close to being fully realized. This is due, in large part, to the challenges associated with the design of optogenetic analogues of endogenous proteins. This review is written from a chemist's perspective, with a focus on the molecular strategies that have been developed for the construction of optogenetic proteins.
Phase Behavior and Aggregation in a Catanionic System Dominated by an Anionic Surfactant Containing a Large Rigid Group
Authors: Zhai Zhaolan , Yan Xinyan , Xu Ji , Song Zhanqian , Shang Shibin , Rao Xiaoping 
Published: April 2018

AbstractThe phase behavior and aggregates of a catanionic system have been investigated. The anionic surfactants in the mixed systems were sodium N‐alkylmaleimidepimaric carboxylate (Cn‐MPA‐Na, n=12, 14, 16), which were prepared from rosin and contain a large rigid skeleton and a flexible alkane chain, and the cationic surfactant was cetyltrimethylammonium bromide (CTAB). The phase behavior of the C14‐MPA‐Na/CTAB system transformed sequentially from a viscoelastic solution to an aqueous surfactant two‐phase system (ASTP), an aqueous surfactant three‐phase system (AS3P), and an anisotropic homogeneous phase as the concentration of C14‐MPA‐Na was continuously increased from 10 to 35 mm. The C16‐MPA‐Na/CTAB system showed similar phase behavior, whereas the C12‐MPA‐Na/CTAB system did not form the AS3P system. The corresponding microstructures in the different phases were investigated by using rheology and cryogenic transmission electron microscopy (Cryo‐TEM). The aggregates in the viscoelastic solutions are thread‐like, annular, and worm‐like micelles. The microstructures in the upper phase of the ASTP are worm‐like micelles, and in the lower phase are spherical and rod‐like micelles. The aggregates in the upper and lower phases of the AS3P are worm‐like micelles and spherical and rod‐like micelles, respectively. The aggregates in the middle phase of the AS3P and the anisotropic homogeneous phase are sponge‐like micelles. The clear Cryo‐TEM images of the sponge‐like micelles are presented.
Potent 3‐Hydroxy‐2‐Pyridine Aldoxime Reactivators of Organophosphate‐Inhibited Cholinesterases with Predicted Blood–Brain Barrier Penetration
Authors: Zorbaz Tamara , Braïki Anissa , Maraković Nikola , Renou Julien , de la Mora Eugenio , Maček Hrvat Nikolina , Katalinić Maja , Silman Israel , Sussman Joel L. , Mercey Guillaume , Gomez Catherine , Mougeot Romain , Pérez Belén , Baati Rachid , Nachon Florian , Weik Martin , Jean Ludovic , Kovarik Zrinka , Renard Pierre‐Yves 
Published: April 2018

AbstractA new series of 3‐hydroxy‐2‐pyridine aldoxime compounds have been designed, synthesised and tested in vitro, in silico, and ex vivo as reactivators of human acetylcholinesterase (hAChE) and butyrylcholinesterase (hBChE) inhibited by organophosphates (OPs), for example, VX, sarin, cyclosarin, tabun, and paraoxon. The reactivation rates of three oximes (16–18) were determined to be greater than that of 2‐PAM and comparable to that of HI‐6, two pyridinium aldoximes currently used by the armies of several countries. The interactions important for a productive orientation of the oxime group within the OP‐inhibited enzyme have been clarified by molecular‐modelling studies, and by the resolution of the crystal structure of the complex of oxime 17 with Torpedo californica AChE. Blood–brain barrier penetration was predicted for oximes 15–18 based on their physicochemical properties and an in vitro brain membrane permeation assay. Among the evaluated compounds, two morpholine‐3‐hydroxypyridine aldoxime conjugates proved to be promising reactivators of OP‐inhibited cholinesterases. Moreover, efficient ex vivo reactivation of phosphylated native cholinesterases by selected oximes enabled significant hydrolysis of VX, sarin, paraoxon, and cyclosarin in whole human blood, which indicates that the oximes have scavenging potential.
Hexakis(3,6‐di‐tert‐butyl‐4‐oxo‐2,5‐cyclohexadien‐1‐ylidene)cyclohexane: Closed‐Shell [6]Radialene or Open‐Shell Hexa‐Radicaloid?
Authors: Feng Jiaqi , Gopalakrishna Tullimilli Y. , Phan Hoa , Wu Jishan 
Published: April 2018

AbstractA star‐shaped hexaquinocyclohexane molecule 4 c is reported, which turns out to be a closed‐shell extended [6]radialene with a twisted‐boat conformation according to X‐ray crystallographic analysis. It was formed by an unusually slow decay of its in situ generated open‐shell valence isomer, the hexa‐radicaloid 4 o, with a half‐life time of about 156 min at room temperature. Reaction progress kinetic analysis revealed a large energy barrier of about 95.5±4.3 kJ mol−1 at room temperature from the hexa‐radical form 4 o to the contorted [6]radialene form 4 c, because the transformation needs to overcome large steric repulsion between the neighboring phenoxyl units. Compound 4 c can be chemically reduced to radical anion and dianion, and the dianion is actually a diradical dianion, with a calculated diradical character of 71.9 %. This study demonstrates the unique chemical bonding nature of contorted quinoidal π‐conjugated molecules and a very unusual valence isomerization process.
Construction of Polycyclic π‐Conjugated Systems Incorporating an Azulene Unit Following the Oxidation of 1,8‐Diphenyl‐9,10‐bis(phenylethynyl)phenanthrene
Authors: Konishi Akihito , Morinaga Atsushi , Yasuda Makoto 
Published: April 2018

AbstractPolycyclic aromatic hydrocarbons (PAHs) that incorporate either heptagons or pentagons consist of non‐planar molecular structures with unusual optoelectronic properties, and the design of a relatively simple and efficient method to construct these highly fused π‐conjugated systems with odd‐membered rings is in high demand. This work describes the use of silver(I) cations to promote the efficient synthesis of azulene‐embedded PAH 2, which is a structural isomer of tribenzo[fg,ij,rst]pentaphene 3, via tandem oxidative transannulation between the phenyl and arylethynyl moieties. This method involves a carbophilic interaction of the silver(I) cation with the acetylene units, which facilitates an electron transfer in the initial step. The synthesized PAH 2 and the protonated cation 2 H⋅BF4 were fully characterized by X‐ray crystallographic analysis, electronic absorption, electrochemical measurement, and quantum chemical calculation. The azulene‐embedded PAH 2 exhibited a low‐energy absorption band and amphoteric redox events, which were characterized as non‐alternant characteristics originating from the azulene unit.
Redox‐Flow‐Batterien im Unterricht
Authors: Quarthal Dominik , Novotny Jana , Oetken Marco 
Published: April 2018

ZusammenfassungDer Beitrag stellt Redox‐Flow‐Batterien vor, welche den didaktischen Vorteil besitzen, dass man ihren Ladezustand anhand ihrer Farbigkeit erkennen kann.