bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ex‐Situ Kinetic Investigations of the Formation of the Poly‐Oxo Cluster U38
Authors: Falaise Clément , Volkringer Christophe , Hennig Christoph , Loiseau Thierry 
Published: September 2015

AbstractThe ex‐situ qualitative study of the kinetic formation of the poly‐oxo cluster U38, has been investigated after the solvothermal reaction. The resulting products have been characterized by means of powder XRD and scanning electron microscopy (SEM) for the solid phase and UV/Vis, X‐ray absorption near edge structure (XANES), extended X‐ray absorption fine structure (EXAFS), and NMR spectroscopies for the supernatant liquid phase. The analysis of the different synthesis batches, stopped at different reaction times, revealed the formation of spherical crystallites of UO2 from t=3 h, after the formation of unknown solid phases at an early stage. The crystallization of U38 occurred from t=4 h at the expense of UO2, and is completed after t=8 h. Starting from pure uranium(IV) species in solution (t=0–1 h), oxidation reactions are observed with a UIV/UVI ratio of 70:30 for t=1–3 h. Then, the ratio is inversed with a UIV/UVI ratio of 25/75, when the precipitation of UO2 occurs. Thorough SEM observations of the U38 crystallites showed that the UO2 aggregates are embedded within. This may indicate that UO2 acts as reservoir of uranium(IV), for the formation of U38, stabilized by benzoate and THF ligands. During the early stages of the U38 crystallization, a transient crystallized phase appeared at t=4 h. Its crystal structure revealed a new dodecanuclear moiety (U12), based on the inner hexanuclear core of {U6O8} type, decorated by three additional pairs of dinuclear U2 units. The U12 motif is stabilized by benzoate, oxalates, and glycolate ligands.
A Cationic MOF with High Uptake and Selectivity for CO2 due to Multiple CO2‐Philic Sites
Authors: Wang Hai‐Hua , Shi Wen‐Juan , Hou Lei , Li Gao‐Peng , Zhu Zhonghua , Wang Yao‐Yu 
Published: September 2015

AbstractThe reaction of N‐rich pyrazinyl triazolyl carboxyl ligand 3‐(4‐carboxylbenzene)‐5‐(2‐pyrazinyl)‐1H‐1,2,4‐triazole (H2cbptz) with MnCl2 afforded 3D cationic metal–organic framework (MOF) [Mn2(Hcbptz)2(Cl)(H2O)]Cl⋅DMF⋅0.5 CH3CN (1), which has an unusual (3,4)‐connected 3,4T1 topology and 1D channels composed of cavities. MOF 1 has a very polar framework that contains exposed metal sites, uncoordinated N atoms, narrow channels, and Cl− basic sites, which lead to not only high CO2 uptake, but also remarkably selective adsorption of CO2 over N2 and CH4 at 298–333 K. The multiple CO2‐philic sites were identified by grand canonical Monte Carlo simulations. Moreover, 1 shows excellent stability in natural air environment. These advantages make 1 a very promising candidate in post‐combustion CO2 capture, natural‐gas upgrading, and landfill gas‐purification processes.
Thermochromism of CuI Tetrakisguanidine Complexes: Reversible Activation of Metal‐to‐Ligand Charge‐Transfer Bands
Authors: Wiesner Sven , Wagner Arne , Hübner Olaf , Kaifer Elisabeth , Himmel Hans‐Jörg 
Published: September 2015

AbstractTetranuclear, intensely blue‐coloured CuI complexes were synthesised in which two Cu2X3− units (X=Br or I) are bridged by a dicationic GFA (guanidino‐functionalised aromatic) ligand. The UV/Vis spectra show a large metal‐to‐ligand charge‐transfer (MLCT) band around 638 nm. The tetranuclear “low‐temperature” complexes are in a temperature‐dependent equilibrium with dinuclear CuI “high‐temperature” complexes, which result from the reversible elimination of two CuX groups. A massive thermochromism effect results from the extinction of the strong MLCT band upon CuX elimination with increasing temperature. For all complexes, quantum chemical calculations predict a small and method‐dependent energy difference between the possible electronic structures, namely CuI and dicationic GFA ligand (closed‐shell singlet) versus CuII and neutral GFA ligand (triplet or broken‐symmetry state). The closed‐shell singlet state is disfavoured by hybrid‐DFT functionals, which mix in exact Hartree–Fock exchange, and is favoured by larger basis sets and consideration of a polar medium.
Light‐Controlled Histone Deacetylase (HDAC) Inhibitors: Towards Photopharmacological Chemotherapy
Authors: Szymanski Wiktor , Ourailidou Maria E. , Velema Willem A. , Dekker Frank J. , Feringa Ben L. 
Published: September 2015

AbstractCancer treatment suffers from limitations that have a major impact on the patient’s quality of life and survival. In the case of chemotherapy, the systemic distribution of cytotoxic drugs reduces their efficacy and causes severe side effects due to nonselective toxicity. Photopharmacology allows a novel approach to address these problems because it employs external, local activation of chemotherapeutic agents by using light. The development of photoswitchable histone deacetylase (HDAC) inhibitors as potential antitumor agents is reported herein. Analogues of the clinically used chemotherapeutic agents vorinostat, panobinostat, and belinostat were designed with a photoswitchable azobenzene moiety incorporated into their structure. The most promising compound exhibits high inhibitory potency in the thermodynamically less stable cis form and a significantly lower activity for the trans form, both in terms of HDAC activity and proliferation of HeLa cells. This approach offers a clear prospect towards local photoactivation of HDAC inhibition to avoid severe side effects in chemotherapy.
Glyconanomaterials for Combating Bacterial Infections
Authors: Ramström Olof , Yan Mingdi 
Published: September 2015

AbstractBacterial infections constitute an increasing problem to human health in response to build‐up of resistance to present antibiotics and sluggish development of new pharmaceuticals. However, a means to address this problem is to pinpoint the drug delivery to—and into—the bacteria. This results in a high local concentration of the drug, circumventing the increasingly high doses otherwise necessary. Combined with other effectors, such as covalent attachment to carriers, rendering the drugs less degradable, and the combination with efflux inhibitors, old drugs can be revived. In this context, glyconanomaterials offer exceptional potential, since these materials can be tailored to accommodate different effectors. In this Concept article, we describe the different advantages of glyconanomaterials, and point to their potential in antibiotic “revitalization”.
A Programmed DNA Marker Based on Bis(4‐ethynyl‐1,8‐naphthalimide) and Three‐Methane‐Bridged Thiazole Orange
Authors: Mao Yueyuan , Liu Keyin , Chen Liang , Cao Xinhua , Yi Tao 
Published: September 2015

AbstractTwo large conjugated naphthalimide derivatives with or without three‐methane‐bridged thiazole orange (TO3; i.e., compounds 1 a and 2 a, respectively) were designed and synthesized. The fluorescence of the naphthalimide group in compound 1 a at λ=532 nm initially decreased and that for the TO3 group at λ=655 nm increased sequentially upon adding Salmon testes (St) DNA. In contrast, without the TO3 group, the fluorescence intensity of compound 2 a monotonously decreased in response to the addition of DNA. The non‐monotonic change in the fluorescence for compound 1 a could be divided into two linear sections with two different wavelengths in the range of 0<Rb/1 a<1.2 and 1.2 <Rb/1 a<6.0 (Rb/1 a=[base pair]/[1 a]). Thus, compound 1 a can be regarded as a programmed responding molecule for DNA, which can semi‐quantitatively determine the concentration of DNA over a large concentration range from the standard fluorescence curve of compound 1 a at different wavelengths when bound with DNA. Furthermore, the binding modes of compounds 1 a and 2 a with StDNA were studied by using CD spectroscopy and melting temperature (Tm) testing. The results showed that compound 1 a interacts with StDNA through multi‐interactions including weak intercalation, weak minor groove binding, and inter‐dye interactions, whereas compound 2 a bound with DNA through simultaneous intercalation and minor groove binding.
New Aggregation‐Induced Emitters: Tetraphenyldistyrylbenzenes
Authors: Freudenberg Jan , Rominger Frank , Bunz Uwe H. F. 
Published: September 2015

AbstractThe synthesis of five novel distyrylbenzene (DSB) derivatives, featuring a central tetraphenylbenzene core, is reported. The targets show aggregation‐induced emission (AIE), which, however, is substituent‐dependent. For the pure hydrocarbon and derivatives that do not carry (+M) or (−M) substituents, classic AIE behavior is observed, that is, the DSBs are non‐fluorescent in solution, but are highly fluorescent in cold matrices, upon aggregate formation in poor solvents and in the solid, crystalline state. If aldehyde or dibutylamino groups are attached in the para‐position of the DSB unit, non‐classic AIE‐phores result. These are fluorescent both in dilute solution as well as in the solid state. Prolonged irradiation of the targets leads to benzotetraphene derivatives by a double cyclization.
Design, Synthesis, and Conformational Analysis of Proposed β‐Turn Mimics from Isoxazoline‐Cyclopentane Aminols
Authors: Memeo Misal Giuseppe , Mella Mariella , Montagna Valentina , Quadrelli Paolo 
Published: September 2015

AbstractConstrained aminols from oxazanorbornene derivatives have the geometrical features to be used as β‐turn inducers. Four different stereoisomers were prepared and spectroscopically characterized (MD calculations, NMR‐titration and VT‐NMR experiments). Temperature coefficients in DMSO are indicative for the existence of an intramolecular hydrogen bond. Chirooptical properties revealed a β‐turn arrangement of all the synthesized compounds, where, depending on the absolute configuration of the cyclopentane spacer, they can be labeled as left‐ or right‐handed turns.
Highly Regioselective Palladium‐Catalyzed Carboxylation of Allylic Alcohols with CO2
Authors: Mita Tsuyoshi , Higuchi Yuki , Sato Yoshihiro 
Published: September 2015

AbstractVarious allylic alcohols were carboxylated in the presence of a catalytic amount of PdCl2 and PPh3 using ZnEt2 as a stoichiometric transmetalation agent under a CO2 atmosphere (1 atm). This carboxylation proceeded in a highly regioselective manner to afford branched carboxylic acids predominantly. The β,γ‐unsaturated carboxylic acid thus obtained was successfully converted into an optically active γ‐butyrolactone, a known intermediate of (R)‐baclofen.
Cationic Cobalt(III)‐Catalyzed Aryl and Alkenyl CH Amidation: A Mild Protocol for the Modification of Purine Derivatives
Authors: Liang Yujie , Liang Yu‐Feng , Tang Conghui , Yuan Yizhi , Jiao Ning 
Published: September 2015

AbstractA cationic cobalt(III)‐catalyzed direct CH amidation of unactivated (hetero)arenes and alkenes by using 1,4,2‐dioxazol‐5‐ones as the amidating reagent has been developed. This transformation proceeds efficiently under external oxidant‐free conditions with a broad substrate scope. Moreover, 6‐arylpurine compounds, which often exhibit high potency in antimycobacterial, cytostatic, and anti‐HCV activities, can be smoothly amidated, thus offering a mild protocol for their late stage functionalization.
Synthesis and Characterization of Fluorinated Polyimide Derived from 3,3′‐Diisopropyl‐4,4′‐diaminodiphenyl‐3′′,4′′‐difluorophenylmethane
Authors: Huang Xiaohua , Mei Mei , Liu Chanjuan , Pei Xianglin , Wei Chun 
Published: September 2015

AbstractA novel aromatic diamine monomer, 3,3′‐diisopropyl‐4,4′‐diaminodiphenyl‐3′′,4′′‐difluorophenylmethane (PAFM), was successfully synthesized by coupling of 2‐isopropylaniline and 3,4‐difluorobenzaldehyde. The aromatic diamine was adopted to synthesize a series of fluorinated polyimides by polycondensation with various dianhydrides: pyromellitic dianhydride (PMDA), 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), 4,4′‐oxydiphthalic anhydride (ODPA) and 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) via the conventional one‐step method. These polyimides presented excellent solubility in common organic solvents, such as N,N‐dimethylformamide (DMF), N,N‐dimethyl acetamide (DMAc), dimethyl sulfoxide (DMSO), N‐methyl‐2‐pyrrolidone (NMP), chloroform (CHCl3), tetrahydrofuran (THF) and so on. The glass transition temperatures (Tg) of fluorinated polyimides were in the range of 260–306°C and the temperature at 10% weight loss in the range of 474–502°C. Their films showed the cut‐off wavelengths of 330–361 nm and higher than 80% transparency in a wavelength range of 385–463 nm. Moreover, polymer films exhibited low dielectric properties in the range of 2.76–2.96 at 1 MHz, as well as prominent mechanical properties with tensile strengths of 66.7–97.4 MPa, a tensile modulus of 1.7–2.1 GPa and elongation at break of 7.2%–12.9%. The polymer films also showed outstanding hydrophobicity with the contact angle in the range of 91.2°–97.9°.
Synthesis, Structural Characterization and Reactivity of a Bis(phosphine)(silyl) Platinum(II) Complex
Authors: Li Yonghua , Zeng Wenjin , Lai Wenyong , Shimada Shigeru , Wang Shi , Wang Lianhui , Huang Wei 
Published: September 2015

AbstractTreatment of 1,2‐C6H4(SiH3)(SiH3) (1) with Pt(dmpe)(PEt3)2 (dmpe=Me2PCH2CH2PMe2) in the ratio of 1:1 leads to the complex {1,2‐C6H4(SiH2)(SiH2)}PtII (dmpe) (2), which can react with proton organic reagent bearing hydroxy group with low steric hindrance to form a tetra‐alkoxy substituted silyl platinum(II) compound (3). Compounds 2 and 3 are the very rare examples of silyl transition‐metal complexes derived from this chelating hydrosilane ligand. To the best of our knowledge, there are only 6 examples of silyl metal complexes prepared from this ligand with such structural features registered in the Cambridge Structural Database, among them, only one silyl platinum(II) compound is presented. The structures of complexes 2 and 3 were unambiguously determined by multinuclear NMR spectroscopic studies and single crystal X‐ray analysis.
A Highly Efficient ZrO2 Nanoparticle Based Electrochemical Sensor for the Detection of Organophosphorus Pesticides
Authors: Wang Haibo , Su Yingchun , Kim Hojong , Yong Daming , Wang Lei , Han Xiaojun 
Published: September 2015

AbstractA sensitive electrochemical method for square‐wave voltammetric detection of organophosphate (OP) compounds was developed based on zirconia (ZrO2) nanoparticles modified electrode. The electrode was fabricated using electrochemical deposition and characterized by scanning electron microscopy (SEM), which confirmed the successful formation of nanoparticles. Due to the strong affinity of ZrO2 with the phosphoric group, nitroaromatic OPs can strongly bind to the surface of ZrO2 nanoparticles (ZrO2NPs). Under optimized operational conditions, SWV was employed for Omethoate (a model of OP compounds) detection with 5 min absorption, which showed a wide detection range from 98.5 pmol·L−1 to 985 nmol·L−1, with a detection limit as low as 52.5 pmol·L−1. This electrochemical sensor has good selectivity, stability and reproducibility, and great potential in the detection of OP compounds in agriculture area.
Highly Enantioselective Intramolecular Morita‐Baylis‐Hillman Reaction Catalyzed by Mannose‐Based Thiourea‐phosphine
Authors: Yang Weihong , Yuan Kui , Song Hongliang , Sha Feng , Wu Xinyan 
Published: September 2015

AbstractThe saccharide‐based chiral bifunctional thiourea‐phosphines were developed as chiral organocatalysts for the intramolecular Morita‐Baylis‐Hillman reaction of ω‐formyl‐enones. With only 2 mol% of thiourea‐phosphine catalyst 3c, chiral functionalized cyclohexenes were achieved under mild reaction conditions with excellent yields and enantioselectivities.
The HAS‐BLED Score for Predicting Major Bleeding Risk in Anticoagulated Patients With Atrial Fibrillation: A Systematic Review and Meta‐analysis
Authors: Zhu Wengen , He Wenfeng , Guo Linjuan , Wang Xixing , Hong Kui 
Published: September 2015

ABSTRACTOur objective was to compare the diagnostic accuracy between the HAS‐BLED score and any of HEMORR2HAGES, ATRIA, CHADS2, or CHA2DS2‐VASc scores in anticoagulated patients with atrial fibrillation. We systematically searched the Cochrane Library, MEDLINE, PubMed, and Embase databases for relevant studies. Data were extracted and analyzed according to predefined clinical endpoints. Eleven studies were identified. Discrimination analysis demonstrates that HAS‐BLED has no significant C‐statistic differences for bleeding risk prediction compared with ATRIA or HEMORR2HAGES, but it has significant differences compared with CHADS2 or CHA2DS2‐VASc. The significant positive net reclassification improvement and integrated discrimination improvement values also show that HAS‐BLED is superior to that of any of HEMORR2HAGES, ATRIA, CHADS2, or CHA2DS2‐VASc scores. According to calibration analysis of HAS‐BLED, it overpredicts the risk of bleeding in the low (risk ratio [RR]: 1.16, 95% confidence interval [CI]: 0.63‐2.13, P = 0.64) risk stratification but underpredicts that in the moderate (RR: 0.66, 95% CI: 0.51‐0.86, P = 0.002) and high (RR: 0.88, 95% CI: 0.70‐1.10, P = 0.27) risk stratifications. The HAS‐BLED score not only performs better than the HEMORR2HAGES and ATRIA bleeding scores, but it also is superior to the CHADS2 and CHA2DS2‐VASc stroke scores for bleeding prediction. The HAS‐BLED score should be the optimal choice to assess major bleeding risk in clinical practice.
Vitamin D Supplementation in the Treatment of Chronic Heart Failure: A Meta‐analysis of Randomized Controlled Trials
Authors: Jiang Wei‐Long , Gu Hai‐Bo , Zhang Yu‐Feng , Xia Qing‐Qing , Qi Jia , Chen Jian‐Chang 
Published: September 2015

ABSTRACTBackgroundIn recent years, there has been growing evidence that vitamin D deficiency is associated with the development and progression of chronic heart failure (CHF).HypothesisAdditional supplementation of vitamin D may have protective effects in patients with CHF.MethodsWe searched PubMed, Embase, and Cochrane databases through June 2015 and included 7 randomized controlled trials that investigated the effects of vitamin D on cardiovascular outcomes in patients with CHF. Then, we performed a meta‐analysis of clinical trials to confirm whether vitamin D supplementation is beneficial in CHF patients. The weighted mean difference (WMD) and 95% confidence interval (CI) were calculated using fixed‐ or random‐effects models.ResultsOur pooled results indicated that additional supplementation of vitamin D was not superior to conventional treatment in terms of left ventricular ejection fraction, N‐terminal pro‐B‐type natriuretic peptide, and 6‐minute walk distance. Moreover, vitamin D supplementation was associated with significant decreases in the levels of tumor necrosis factor‐α (WMD: −2.42 pg/mL, 95% CI: −4.26 to −0.57, P < 0.05), C‐reactive protein (WMD: −0.72 mg/L, 95% CI: −1.42 to −0.02, P < 0.05), and parathyroid hormone (WMD: −13.44 pg/mL, 95% CI: −21.22 to −5.67, P < 0.05).ConclusionsVitamin D supplementation may decrease serum levels of parathyroid hormone and inflammatory mediators in CHF patients, whereas it has no beneficial effects on improvement of left ventricular function and exercise tolerance.
Brain size and limits to adult neurogenesis
Authors: Paredes Mercedes F. , Sorrells Shawn F. , Garcia‐Verdugo Jose M. , Alvarez‐Buylla Arturo 
Published: September 2015

ABSTRACTThe walls of the cerebral ventricles in the developing embryo harbor the primary neural stem cells from which most neurons and glia derive. In many vertebrates, neurogenesis continues postnatally and into adulthood in this region. Adult neurogenesis at the ventricle has been most extensively studied in organisms with small brains, such as reptiles, birds, and rodents. In reptiles and birds, these progenitor cells give rise to young neurons that migrate into many regions of the forebrain. Neurogenesis in adult rodents is also relatively widespread along the lateral ventricles, but migration is largely restricted to the rostral migratory stream into the olfactory bulb. Recent work indicates that the wall of the lateral ventricle is highly regionalized, with progenitor cells giving rise to different types of neurons depending on their location. In species with larger brains, young neurons born in these spatially specified domains become dramatically separated from potential final destinations. Here we hypothesize that the increase in size and topographical complexity (e.g., intervening white matter tracts) in larger brains may severely limit the long‐term contribution of new neurons born close to, or in, the ventricular wall. We compare the process of adult neuronal birth, migration, and integration across species with different brain sizes, and discuss how early regional specification of progenitor cells may interact with brain size and affect where and when new neurons are added. J. Comp. Neurol. 524:646–664, 2016. © 2015 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.
A New Scheme for High‐Intensity Laser‐Driven Electron Acceleration in a Plasma
Authors: Sadykova S. P. , Rukhadze A. A. , Samkharadze T. G. 
Published: September 2015

AbstractWe propose a new approach to high‐intensity relativistic laser‐driven electron acceleration in a plasma. Here, we demonstrate that a plasma wave generated by a stimulated forward‐scattering of an incident laser pulse can be in the longest acceleration phase with injected relativistic beam electrons. This is why the plasma wave has the maximum amplification coefficient which is determined by the acceleration time and the breakdown (overturn) electric field in which the acceleration of the injected beam electrons occurs. We must note that for the longest acceleration phase the relativity of the injected beam electrons plays a crucial role in our scheme. We estimate qualitatively the acceleration parameters of relativistic electrons in the field of a plasma wave generated at the stimulated forward‐scattering of a high‐intensity laser pulse in a plasma. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Orbital‐Free Quantum Hypernetted Chain Model Based Perturbation Theory for Equation of State of Hydrogen and Helium in Warm Dense Regime
Authors: Sai Venkata Ramana A. 
Published: September 2015

AbstractWe present in this work, a thermodynamic perturbation theory for equation of state of hydrogen and helium in the warm dense regime. The system is modeled as a mixture of classical point ions and quantum electrons. A perturbation series for Helmholtz free energy and correlation functions of the ions and electrons as a function of density and temperature is proposed. Combining the classical thermodynamic perturbation theory and the orbitial‐free quantum hyper‐netted chain theory, a systematic procedure to obtain the terms of the perturbation series is developed. The ion‐ion correlations are treated within the hyper‐netted chain approximation and the ion‐electron correlations are treated within the Thomas‐Fermi‐Dirac‐Weizsäcker approximation. The method has been applied to obtain isotherms of hydrogen and helium in the warm dense regime. The isotherms are compared with available ab‐initio data and the results are analyzed. A good agreement with ab‐initio data has been observed for pressures greater than one Mbar. Advantages and limitations of the present method are discussed along with possible future improvements. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)