bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organisch‐anorganische Perowskit‐Dünnfilme für hocheffiziente Solarzellen
Authors: Stranks Samuel D. , Nayak Pabitra K. , Zhang Wei , Stergiopoulos Thomas , Snaith Henry J. 
Published: February 2015

AbstractOrganisch‐anorganische Perowskite sind ein hochaktuelles Thema in der Photovoltaikforschung. Die Wirkungsgrade von Laborzellen auf Perowskit‐Basis konkurrieren mittlerweile mit etablierten Dünnfilmtechnologien. Die größten Fortschritte wurden bislang durch Verbesserungen der Filmqualitäten erreicht, und man kann vermuten, dass die Optimierung von Schichtbildung und Kristallisation der Perowskitfilme von höchster Bedeutung für weitere Effizienzsteigerungen sind. Hier fassen wir die verschiedenen Schichtbildungstechniken zusammen und diskutieren den Einfluss von Lösungsmittel und Ausgangsprodukten im Prozess. Wir besprechen, welche Rolle Chlorid in der Schichtbildung von gemischten Halogenid‐Perowskiten spielt – eine der zentralen Fragen auf dem Gebiet. Des Weiteren betrachten wir die Materialeigenschaften, die für die Funktion von Hochleistungssolarzellen essenziell sind, und identifizieren Wege für die weitere Verbesserung der Morphologien.
Steigerung der Interkombinationseffizienz in Phenothiazinfarbstoffen durch Einlagerung in DNA
Authors: Nogueira Juan J. , Oppel Markus , González Leticia 
Published: February 2015

AbstractPhenothiazinfarbstoffe werden als Photosensibilisatoren in der photodynamischen Therapie eingesetzt. Ihr Wirkmodus ist eng an die Erzeugung von angeregten Triplettzuständen durch Interkombination geknüpft. Das Verständnis der Faktoren, welche die Interkombination beeinflussen, ist daher essenziell zur Verbesserung der Wirksamkeit der photodynamischen Therapie. Wir setzen eine Kombination aus quantenmechanischen und molekülmechanischen Rechenverfahren ein, um die Effekte einer wässrigen und einer DNA‐Umgebung auf den Mechanismus der Interkombination in Methylenblau zu untersuchen. Dabei stellt sich heraus, dass die Erzeugung von Triplettzuständen stark von der Umgebung beeinflusst wird. Während die Interkombination in Wasser ausschließlich durch vibronische Spin‐Bahn‐Kopplungen ausgelöst wird, findet sich in DNA‐Umgebung ein weiterer, durch elektronische Spin‐Bahn‐Kopplung vermittelter Weg. Konkurrierende, in DNA‐Umgebungen ebenfalls mögliche Ladungstransferprozesse können daher unterdrückt werden, um die Wirksamkeit der photodynamischen Therapie zu erhöhen.
Elektroneninduzierte Hydratisierung eines Alkens: alternative Reaktionswege
Authors: Warneke Jonas , Wang Ziyan , Swiderek Petra , Bredehöft Jan Hendrik 
Published: February 2015

AbstractElektroneninduzierte Reaktionen in kondensierten Mischungen aus Ethen und Wasser führen zur Synthese von Ethanol, wie sich anhand von thermischer Desorptionsspektrometrie (TDS) nach Bestrahlung zeigen lässt. Diese Reaktion wird nicht nur durch Elektronenstoß‐Ionisation nahe der Ionisationsschwelle ausgelöst, sondern auch durch Elektronenanlagerung an Ethen und eine nachfolgende Säure‐Base‐Reaktion mit Wasser.
Unexpected Luminescence Behavior of Coinage Metal π‐Diborene Complexes
Authors: Bissinger Philipp , Steffen Andreas , Vargas Alfredo , Dewhurst Rian D. , Damme Alexander , Braunschweig Holger 
Published: February 2015

AbstractA number of unprecedented photophysical phenomena were observed in the study of luminescent π‐diborene complexes of Cu and Ag. These observations included unusually high fluorescence quantum yields (up to 100%) in solution for complexes of these metals. This result indicates that very little or no intersystem crossing between S1 and Tn occurs in the complexes, despite the strong spin–orbit coupling of the metal atoms. The replacement of carbon with boron thus yields luminescent isolobal analogues of otherwise non‐emissive olefin complexes of Cu and Ag.
Building of a sulfonyl‐group‐functionalized monomer whose polymer is able to catalyze biodiesel formation
Authors: Gomez Cesar G. , Anníbali German N. , Strumia Miriam C. 
Published: February 2015

ABSTRACTA linear polymer containing sulfonyl groups was synthesized from a vinyl monomer to use its acid group as a catalyst of the esterification of oleic acid to form biodiesel. First, synthesis optimization of the monomer was carried out in an aqueous system. This molecule was obtained in an excellent yield, where the pH and reaction time were decisive factors in the synthesis performance. The vinyl monomer was then polymerized, and the catalytic activity of the sulfonic acid could be demonstrated in the esterification of oleic acid with short‐chain alcohols. The increase in the catalyst content resulted in a higher concentration of the carbonyl group activated, and this was followed by faster esterification kinetics. The highest yield (98 mol %) was reached after 20 min when a 10 mol‐% of catalyst was used. A larger size alcohol led to slower esterification kinetics because its ability as a nucleophile was decreased by steric impediment. The sulfonyl group in polymer 4, an aryl sulfonic acid polymer, proved to be an acid almost as efficient as sulfuric acid, although the former worked in a heterogeneous system. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41957.
Preparation and application of aluminum‐doped zinc oxide powders via precipitation and plasma processing method
Authors: Wang Xianjun , Zhang Ping , Hong Ruoyu 
Published: February 2015

ABSTRACTAluminum‐doped zinc oxide (AZO) conductive powders were successfully obtained through an attractive method based on the pyrolysis of coprecipitated precursors in arc plasma processing. The as‐prepared powders were characterized by the x‐ray diffraction (XRD), transmission electron microscopy (TEM), and UV‐vis spectrum. The results reveal that Al atoms are doped into ZnO lattice successfully and all the samples are polycrystalline with a hexagonal wurtzite structure. Moreover, the particle size of aluminum doped zinc oxide prepared from the plasma pyrolysis was smaller than conventional thermal calcination. Afterward, the synthesized powders were reinforced into polypropylene (PP) matrix and the dispersion of the AZO filler in the PP matrix was observed by SEM. In addition, the effect of AZO concentrations on the electrical and mechanical properties of PP composites was investigated via resistance measurement, tensile and impact tests, respectively. The results show that the electrical and mechanical properties depend on the concentration and dispersion of AZO nanoparticles in the matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41990.
A Facile and Universal Method to Prepare Hydrophilic Molecularly Imprinted Microspheres by Encapsulating a Polymer in Hollow Mesoporous Silica Microspheres
Authors: Yang Shun , Li Najun , Xing Qingjian , Chen Dongyun , Xu Qingfeng , Li Hua , Lu Jianmei 
Published: February 2015

AbstractHydrophilic molecularly imprinted microspheres (MIP@SiO2) for the adsorption of water‐soluble molecules in real aqueous samples were successfully synthesized. In this strategy, a molecular imprinted polymer (MIP) was encapsulated in the hollow core of hollow mesoporous silica (HMS) particles via a ‘ship‐in‐a‐bottle’ process. As the HMS shell contains plenty of Si‐OH groups, the as‐prepared microspheres proved to be hydrophilic and could be well dispersed in water. On the other hand, the MIP encapsulated in the HMS could specifically recognize small molecules with good binding efficiency through the mesoporous silica shell. Binding experiments in real aqueous solutions showed that the MIP@SiO2 composites have excellent recognition ability for specific molecules. Thus, MIP@SiO2 are highly promising alternatives to biological receptors with great potential for many analytical applications, such as environmental, food, and clinical analyses and other areas.
Photofunctional Platinum Complexes Featuring N‐heterocyclic Carbene‐Based Pincer Ligands
Authors: Lin Wan‐Jung , Naziruddin Abbas Raja , Chen Yu‐Hsuan , Sun Bian‐Jian , Chang A. Hsiu Hwa , Wang Wen‐Jwu , Hwang Wen‐Shu 
Published: February 2015

AbstractPhotoactive platinum complexes of stoichiometry [Pt(RCCCR)L]0/+ (R=Me, nBu and L=CN, C≡CPh, N≡CCH3, Py, CO) featuring pincer‐type bis N‐heterocyclic carbene (NHC) ligands (RCCCR) were synthesized. Organometallic syntheses of these complexes are facile and achievable through standard laboratory procedures. Control of intermolecular Pt⋅⋅⋅Pt interaction, π–π stacking, and emission tuning is achieved through suitable choice of the NHC‐wingtip substituent (R) and the auxiliary ligand (L). Exposure to specific volatile organic compounds (VOCs) or mechanical grinding triggers changes in emission colors, which render these complexes photofunctional. Solid‐state structures and photoluminescence results are described herein.
Synthesis of Indole Terpenoid Mimics through a Functionality‐Tolerated Eu(fod)3‐Catalyzed Conjugate Addition
Authors: Xiong Xiaochun , Zhang Deliang , Li Jian , Sun Yu , Zhou Shupeng , Yang Ming , Shao Huawu , Li Ang 
Published: February 2015

AbstractThe chemical synthesis of indole terpenoids of structural and biological interests has attracted remarkable attention. Here we report an Eu(fod)3‐catalyzed indole conjugate addition reaction, which tolerates various acid‐sensitive functional groups. A collection of indole terpenoid mimics have been prepared from natural product‐derived α,β‐unsaturated enones on the basis of this reaction. The further conversion of the indole adducts into more complex natural product‐like molecules has also been demonstrated.
Moisture sources of an extreme precipitation event in Sichuan, China, based on the Lagrangian method
Authors: Huang Yongjie , Cui Xiaopeng 
Published: February 2015

AbstractIn July 2013, an extreme precipitation event occurred in Sichuan, China, causing severe flooding, debris flows, and substantial losses. Moisture sources and transport of this event and quantification of the contribution from moisture sources were studied using the Lagrangian method. The results show that the vast majority of particles influencing this event originated from the relatively lower troposphere south of the precipitation region and can be traced back to the Arabian Sea. Moreover, the total moisture from the source regions accounts for more than 80% of the precipitation; moisture originating from the India Peninsula–Bay of Bengal–Indo‐China Peninsula region had the highest contribution.
CRISPR genome engineering and viral gene delivery: A case of mutual attraction
Authors: Schmidt Florian , Grimm Dirk 
Published: February 2015

AbstractThe adaptation of the CRISPR/Cas9 DNA engineering machinery for mammalian cells has revolutionized our approaches to low‐ or high‐throughput genome annotation and paved the way for conceptually novel therapeutic strategies. A large part of the attraction of CRISPR stems from the small size of its two core components – Cas9 and gRNA – and hence its compatibility with virtually any available viral vector delivery system. As a result, over the past two years, four major classes of viral vectors have already been engineered and applied as CRISPR delivery tools – retroviruses, lentiviruses, adenoviruses, and adeno‐associated viruses (AAVs). The juxtaposition of these two technologies reflects a case of tremendous mutual attraction and holds unprecedented promises for biology and medicine. Here, we provide an overview of the state‐of‐the‐art of this rapidly emerging field, from a comparative description of the principal vector designs, to a synopsis of some of the most exciting applications that were reported to date, including the use of viral CRISPR vectors for genome‐wide loss‐of‐function screens, multiplexed gene editing or disease modeling in animals. Once specificity and safety have been improved further, viral vector‐mediated in vitro/in vivo CRISPR delivery and expression promise to radically transform basic and applied biomedical research.
A Peptide‐Functionalized Polymer as a Minimal Scaffold Protein To Enhance Cluster Formation in Early T Cell Signal Transduction
Authors: Witsenburg J. Joris , Sinzinger Michael D. , Stoevesandt Oda , Ruttekolk Ivo R. , Roth Günter , Adjobo‐Hermans Merel J. W. , Brock Roland 
Published: February 2015

AbstractIn cellular signal transduction, scaffold proteins provide binding sites to organize signaling proteins into supramolecular complexes and act as nodes in the signaling network. Furthermore, multivalent interactions between the scaffold and other signaling proteins contribute to the formation of protein microclusters. Such microclusters are prominent in early T cell signaling. Here, we explored the minimal structural requirement for a scaffold protein by coupling multiple copies of a proline‐rich peptide corresponding to an interaction motif for the SH3 domain of the adaptor protein GADS to an N‐(2‐hydroxypropyl)methacrylamide polymer backbone. When added to GADS‐containing cell lysates, these scaffolds (but not individual peptides) promoted the binding of GADS to peptide microarrays. This can be explained by the cross‐linking of GADS into larger complexes. Furthermore, following import into Jurkat T cell leukemia cells, this synthetic scaffold enhanced the formation of microclusters of signaling proteins.
Rapid Parallel Synthesis of Bioactive Folded Cyclotides by Using a Tea‐Bag Approach
Authors: Aboye Teshome , Kuang Yuting , Neamati Nouri , Camarero Julio A. 
Published: February 2015

AbstractWe report here the first rapid parallel production of bioactive folded cyclotides by using Fmoc‐based solid‐phase peptide synthesis in combination with a “tea‐bag” approach. Using this approach, we efficiently synthesized 15 analogues of the CXCR4 antagonist cyclotide MCo‐CVX‐5c. Cyclotides were synthesized in a single‐pot, cyclization/folding reaction in the presence of reduced glutathione. Natively folded cyclotides were quickly purified from the cyclization/folding crude mixture by activated thiol Sepharose‐based chromatography. The different folded cyclotide analogues were then tested for their ability to inhibit the CXCR4 receptor in a cell‐based assay. The results indicated that this approach can be used for the efficient chemical synthesis of libraries of cyclotides with improved biological properties that can be easily interfaced with solution or cell‐based assays for rapid screening.
Bioorthogonal Probes for Imaging Sterols in Cells
Authors: Jao Cindy Y. , Nedelcu Daniel , Lopez Lyle V. , Samarakoon Thilani N. , Welti Ruth , Salic Adrian 
Published: February 2015

AbstractCholesterol is a fundamental lipid component of eukaryotic membranes and a precursor of potent signaling molecules, such as oxysterols and steroid hormones. Cholesterol and oxysterols are also essential for Hedgehog signaling, a pathway critical in embryogenesis and cancer. Despite their importance, the use of imaging sterols in cells is currently very limited. We introduce a robust and versatile method for sterol microscopy based on C19 alkyne cholesterol and oxysterol analogues. These sterol analogues are fully functional; they rescue growth of cholesterol auxotrophic cells and faithfully recapitulate the multiple roles that sterols play in Hedgehog signal transduction. Alkyne sterol analogues incorporate efficiently into cellular membranes and can be imaged with high resolution after copper(I)‐catalyzed azide–alkyne cycloaddition reaction with fluorescent azides. We demonstrate the use of alkyne sterol probes for visualizing the subcellular distribution of cholesterol and for two‐color imaging of sterols and choline phospholipids. Our imaging strategy should be broadly applicable to studying the role of sterols in normal physiology and disease.
Hydrophobic Mesoporous Poly(ionic liquid)s towards Highly Efficient and Contamination‐Resistant Solid‐Base Catalysts
Authors: Wang Xiaochen , Li Jing , Chen Guojian , Guo Zengjing , Zhou Yu , Wang Jun 
Published: February 2015

AbstractMesoporous poly(ionic liquid)s were synthesized by radical copolymerization of the ionic liquid 1‐aminoethyl‐3‐vinylimidazolium bromide with divinylbenzene plus the ion exchange of bromide anions with hydroxyls. Characterizations revealed the high ionic liquid content, large surface area, and hydrophobicity for the sample prepared with equimolar amounts of ionic liquid and divinylbenzene, with good accessibility to organic compounds and resistance to CO2/H2O contamination. The mesoporous copolymer behaved as a superior and recyclable solid‐base catalyst for solvent‐free Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate, giving the much higher turnover frequency of 304 h−1 (yield 99 %, 0.5 h) than those of the nonporous analogues, commercial strong basic resins, and even homogeneous NaOH. The high activity was confirmed by Knoevenagel condensation with various substrates and Claisen–Schmidt condensation. A possible synergistic Lewis–Brønsted dual‐base‐center mechanism is proposed for understanding the catalytic behavior.
Synthesis, Crystal Structure, and Colloidal Dispersions of Vanadium Tetrasulfide (VS4)
Authors: Kozlova Mariia N. , Mironov Yuri V. , Grayfer Ekaterina D. , Smolentsev Anton I. , Zaikovskii Vladimir I. , Nebogatikova Nadezhda A. , Podlipskaya Tatyana Yu. , Fedorov Vladimir E. 
Published: February 2015

AbstractAlthough many of the layered metal chalcogenides, such as MoS2, are well‐studied, some other chalcogenides have received less attention by comparison. In particular, there has been an emerging interest in vanadium tetrasulfide (VS4), which displays useful properties as a component of hybrids. However, the synthetic methods and characteristics of individual VS4 are not yet well defined, and there is no report on its solution processability. Here we have synthesized VS4 by a simple and fast direct reaction between elements. Reinvestigation of the VS4 crystal structure yielded more precise atomic coordinates and interatomic distances, thereby confirming the crystallization of VS4 in the monoclinic C2/c group and its quasi‐1D chainlike structure. As the chains in VS4 are only bonded by weak van der Waals forces, we further demonstrate that bulk VS4 may be ultrasonically dispersed in appropriate solvents to form colloids, similarly to the layered chalcogenides. VS4 particles in colloids retain their phase identity and rod‐shaped morphology with lengths in the range of hundreds of nanometers. Isopropanol dispersion exhibited the highest concentration and stability, which was achieved owing to the repulsion caused by high negative charges on the edges of the particles.
Hydrogen Production on a Hybrid Photocatalytic System Composed of Ultrathin CdS Nanosheets and a Molecular Nickel Complex
Authors: Xu You , Yin Xuguang , Huang Yi , Du Pingwu , Zhang Bin 
Published: February 2015

AbstractThe production of clean and renewable hydrogen through water splitting by using solar energy has received much attention due to the increasing global energy demand. We report an economic and artificial photosynthetic system free of noble metals, consisting of ultrathin CdS nanosheets as a photosensitizer and nickel‐based complex as a molecular catalyst. Emission quenching and flash photolysis studies reveal that this hybrid system allows for effective electron transfer from the excited CdS nanosheets to the nickel‐based complex to generate reduced intermediate species for efficient hydrogen evolution. Notably, the unique morphological and structural features of the ultrathin CdS nanosheets contribute to the highly efficient photocatalytic performance. As a consequence, the resulting system shows exceptional activity and stability for photocatalytic hydrogen evolution in aqueous solution with a turnover number (TON) of about 28 000 versus catalyst and a lifetime of over 90 h under visible light irradiation.
Catalytic Asymmetric Crotylation of Aldehydes: Application in Total Synthesis of (−)‐Elisabethadione
Authors: O'Hora Paul S. , Incerti‐Pradillos Celia A. , Kabeshov Mikhail A. , Shipilovskikh Sergei A. , Rubtsov Aleksandr E. , Elsegood Mark R. J. , Malkov Andrei V. 
Published: February 2015

AbstractA new, highly efficient Lewis base catalyst for a practical enantio‐ and diastereoselective crotylation of unsaturated aldehydes with E‐ and Z‐crotyltrichlorosilanes has been developed. The method was employed as a key step in a novel asymmetric synthesis of bioactive serrulatane diterpene (−)‐elisabethadione. Other strategic reactions for setting up the stereogenic centers included anionic oxy‐Cope rearrangement and cationic cyclization. The synthetic route relies on simple, high yielding reactions and avoids use of protecting groups or chiral auxiliaries.
A Potent Anticancer Agent of Shikonin Derivative Targeting Tubulin
Authors: Baloch Shahla Karim , Ma Lin , Xu Guo‐Hua , Bai Li‐Fei , Zhao Hua , Tang Cheng‐Yi , Pang Yan‐Jun , Yang Rong‐Wu , Wang Xiao‐Ming , Lu Gui‐Hua , Yang Yong‐Hua 
Published: February 2015

AbstractIn this study, a shikonin ester derivative, compound 3g, was selected to evaluate its anticancer activities and we found that compound 3g exhibited better antitubulin activities against the human HepG2 cell line with an IC50 value of 1.097 μM. Furthermore, the inhibition of tubulin polymerization results indicated that compound 3g demonstrated the most potent antitubulin activity (IC50 = 13.88), which was compared with shikonin and colchicine as positive controls (IC50 = 25.28 μM and 22.56 μM), respectively. Compound 3g was simulated to have good binding site with tubulin and arrested the cell cycle at G2/M phase, which also induces apoptosis in HepG2 cells, in which P53 and members of Bcl‐2 protein family were both involved in the progress of apoptosis revealed by western blot. Confocal microscopy observations revealed compound 3g targeted tubulin and altered its polymerization by interfering with microtubule organization. Based on these results, compound 3g functions as a potent anticancer agent targeting tubulin. Chirality 27:274–280, 2015.. © 2015 Wiley Periodicals, Inc.
Rational macromodeling of 1D blood flow in the human cardiovascular system
Authors: Ferranti Francesco , Tamburrelli Vincenzopio , Antonini Giulio 
Published: February 2015

SummaryIn this paper, we present a novel rational macromodeling approach for the description of 1D blood flow in the human cardiovascular system, which is suitable for time‐domain simulations. Using the analogy of the blood flow propagation problem with transmission lines and considering the hypothesis of linearized Navier–Stokes equations, a frequency‐domain rational macromodel for each arterial segment has been built. The poles and the residues of each arterial segment macromodel have been calculated by means of the Vector Fitting technique. Finally, the rational macromodel of the whole cardiovascular system is obtained by properly combining the macromodels of the single arterial segments using an interconnect matrix. The rational form of the proposed cardiovascular model leads to a state‐space or electrical circuit model suitable for time‐domain analysis. The stability and passivity properties of the global cardiovascular model are discussed to guarantee stable time‐domain simulations. The proposed macromodeling approach has been validated by pertinent numerical results. Copyright © 2015 John Wiley & Sons, Ltd.