bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydration of Lanthanoids(III) and Actinoids(III): An Experimental/Theoretical Saga
Authors: D'Angelo Paola , Spezia Riccardo 
Published: August 2012

AbstractThe latest experimental and theoretical studies on structural and dynamical properties of lanthanoid(III) and actinoid(III) ions in water have been reviewed. In the last years, most of the issues about lanthanoid(III) hydration have been resolved combining X‐ray absorption experiments and different theoretical methods. Since 2008 an effort has been made to treat the entire series thus obtaining coherent sets of experimental and theoretical results that were lately put together in such a way that it was possible to derive new basic properties, such as effective ionic radii, across the series. While for the hydration of lanthanoids(III) many experiments and simulations have been reported, the hydration of actinoids(III) was less investigated. There are some experiments performed by different research groups and few simulations that we discuss in this review. Currently, there are enough results that it is possible to gain some understanding of the hydration behavior of lanthanoids(III) and actinoids(III). The ultimate goal of this review is to provide clues on the analogies and differences between the two series. These aspects are connected to several issues: 1) technological: the separation of these elements that is necessary for recycling and stocking of nuclear waste, 2) practical: because experiments on actinoids need particular care, the definition of possible analogies will give the possibility to use the correct lanthanoid when the information on a specific actinoid is needed, 3) fundamental: related to chemical similarities between the two series.
Synthesis and Photovoltaic Properties of Two‐Dimensional Low‐Bandgap Copolymers Based on New Benzothiadiazole Derivatives with Different Conjugated Arylvinylene Side Chains
Authors: Peng Qiang , Lim Siew‐Lay , Wong Ivy Hoi‐Ka , Xu Jun , Chen Zhi‐Kuan 
Published: August 2012

AbstractA new series of 2,1,3‐benzothiadiazole (BT) acceptors with different conjugated aryl‐vinylene side chains have been designed and used to build efficient low‐bandgap (LBG) photovoltaic copolymers. Based on benzo[1,2‐b:3,4‐b′]dithiophene and the resulting new BT derivatives, three two‐dimensional (2D)‐like donor (D)–acceptor (A) conjugated copolymers have been synthesised by Stille coupling polymerisation. These copolymers were characterised by NMR spectroscopy, gel‐permeation chromatography, thermogravimetric analysis and differential scanning calorimetry. UV/Vis absorption and cyclic voltammetry measurements indicated that their optical and electrochemical properties can be facilely modified by changing the structures of the conjugated aryl‐vinylene side chains. The copolymer with phenyl‐vinylene side chains exhibited the best light harvesting and smallest bandgap of the three copolymers. The basic electronic structures of D–A model compounds of these copolymers were also studied by DFT calculations at the B3LYP/6‐31G* level of theory. Polymer solar cells (PSCs) with a typical structure of indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS)/copolymer:[6,6]‐phenyl‐C61(C71)‐butyric acid‐methyl ester (PCBM)/calcium (Ca)/aluminum (Al) were fabricated and measured under the illumination of AM1.5G at 100 mW cm−2. The results showed that the device based on the copolymer with phenyl‐vinylene side chains had the highest efficiency of 2.17 % with PC71BM as acceptor. The results presented herein indicate that all the prepared copolymers are promising candidates for roll‐to‐roll manufacturing of efficient PSCs. Suitable electronic, optical and photovoltaic properties of BT‐based copolymers can also be achieved by fine‐tuning the structures of the aryl‐vinylene side chains for photovoltaic application.
Hapticity Uncovered: Real‐Space Bonding Indicators for Zincocene Chemistry
Authors: Mebs Stefan , Chilleck Maren A. , Grabowsky Simon , Braun Thomas 
Published: August 2012

AbstractThe connectivities (hapticities) of asymmetric cyclopentadienyl zinc compounds are determined by theoretically obtained real‐space bonding descriptors. The methods employed herein include the determination of the number of virial paths and electron localizability indicator (ELI‐D) basins exhibited between the central Zn atom and the atoms of the ring system. Metal–ring interactions are characterized by flat electron densities and small density gradients, which are related to the high fluxionality of the rings. Due to this, the structures are topologically unstable and the conventional bond‐path analysis within the atoms in molecules (AIM) scheme, which in principle can also be applied for experimental electron densities reconstructed from high‐resolution X‐ray diffraction data, is not a reliable tool for the determination of the hapticity. As a consequence, the theoretical investigation of other real‐space bonding descriptors is the necessary primary step for discovering bonding modes that can be applied to molecular geometries obtained by subsequent experiments. By this procedure the common geometrical interpretation of connectivities, which is based on rather arbitrary decisions, is complemented by a self‐consistent method using electronic descriptors. Moreover, the two‐center σ contributions of all possible bonding scenarios (η1–η5) were quantified by analyzing the electron populations of the ZnC σ‐bonding basins from the ELI‐D analysis inside the AIM Zn atom in relation to the corresponding populations of the CC π basins of the unsaturated rings. The investigation of the Zn–ring interactions is extended to the delocalization index, the source function, and a new type of electron‐density‐based surfaces, which we introduce here (ASF=aspherical stockholder fragments). They can be used for visualization of single atoms, fragments (e.g., functional groups), and whole molecules and are based on Hirshfeld’s idea of stockholder partitioning, but apply aspherical electron densities. With these surfaces the charge accumulation between the chosen fragments and the steric accessibility of the central Zn atoms become visible, which is a useful tool for explaining and predicting chemical reactivity.
Electrochemical Preparation of Luminescent Graphene Quantum Dots from Multiwalled Carbon Nanotubes
Authors: Shinde Dhanraj B. , Pillai Vijayamohanan K. 
Published: August 2012

AbstractGreen luminescent, graphene quantum dots (GQDs) with a uniform size of 3, 5, and 8.2(±0.3) nm in diameter were prepared electrochemically from MWCNTs in propylene carbonate by using LiClO4 at 90 °C, whereas similar particles of 23(±2) nm were obtained at 30 °C under identical conditions. Both these sets of GQDs displayed a remarkable quantum efficiency of 6.3 and 5.1 %, respectively. This method offers a novel strategy to synthesise size‐tunable GQDs as evidenced by multiple characterisation techniques like transmission and scanning electron microscopy, atomic force microscopy, Raman spectroscopy and X‐ray diffraction (XRD). Photoluminescence of these GQDs can be tailored by size variation through a systematic change in key process parameters, like diameter of carbon nanotube, electric field, concentration of supporting electrolyte and temperature. GQDs are promising candidates for a variety of applications, such as biomarkers, nanoelectronic devices and chemosensors due to their unique features, like high photostability, biocompatibility, nontoxicity and tunable solubility in water.
Selective Functionalization of Fullerenes with N,N‐Dihalosulfonamides as an N1 Unit: Versatile Syntheses of Aza[60]fulleroids and Aziridino[60]fullerenes and their Application to Photovoltaic Cells
Authors: Nagamachi Toshiki , Takeda Youhei , Nakayama Kazuhisa , Minakata Satoshi 
Published: August 2012

AbstractHighly selective and versatile methods for the synthesis of aza[60]fulleroids and aziridino[60]fullerenes from C60 have been developed. The reactions utilized N,N‐dihalosulfonamides as an N1 source. The photophysical, electrochemical, and thermal properties of the iminofullerenes were investigated by means of UV/Vis spectroscopy, cyclic voltammetry, and thermogravimetry, respectively. Furthermore, photovoltaic cells based on the synthesized iminofullerenes were fabricated. The power conversion efficiencies (PCEs) of the devices showed moderate values ranging from 1.33 to 2.35 %.
Continuous Fermentation with Animal Cells. Part 1. Aspects of the Continuous Process
Authors: Henzler Hans‐Jürgen 
Published: August 2012

AbstractDie kontinuierliche Fermentation verspricht im Vergleich zur diskontinuierlichen Prozessführung eine Reihe von Vorteilen. Dazu zählen der Langzeitbetrieb bei weitgehend konstanter Substrat‐, Zellmasse und Produktkonzentration sowie eine hohe Anlagen‐Produktivität. Demgegenüber stehen eine komplexere Fermentationstechnik und die Notwendigkeit, die Langzeitsterilität bei sterilen Prozessen zu sichern. Einführend werden die Grundlagen der kontinuierlichen Fermentation zum Anfahrvorgang und stationären Betrieb behandelt. Eine konsequent angewendete dimensionslose Formulierung der maßgebenden Zusammenhänge ermöglicht eine kompakte und besonders übersichtliche Darstellung der grundlegenden Gesetzmäßigkeiten zur Zellmasse‐ und Produktbildung. Es werden die Besonderheiten der kontinuierlichen Fermentation mit und ohne Zellrückhaltung gegenübergestellt und grundlegende Aspekte der kontinuierlichen Fermentation mit Zellrückhaltung besprochen.
Preparation of Multi‐Metal Oxide Hollow Sphere Using Layered Double Hydroxide Precursors
Authors: Yang Miaosen , Zhang Guoxin , Wu Caiying , Chang Zheng , Sun Xiaoming , Duan Xue 
Published: August 2012

AbstractA simple and versatile synthesis method was developed to prepare inorganic multi‐metal oxide hollow spheres with tunable compositions. The colloidal nanosheets of layered double hydroxides (LDH) with pre‐determined compositions were used as precursors for multi‐metal oxides and carbon spheres (CSs) prepared by hydrothermal carbonization of glucose were used as hard templates. Electrostatic force drove the positively charged LDH nanosheets to be anchored by the negatively charged CSs once they were mixed, leading to the formation of core‐shell structures. Finally, multi‐metal oxides with hollow spherical structures were obtained by calcination. These hollow spheres were characterized by X‐ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and inductively coupled plasma (ICP). Results revealed that the as‐prepared oxide hollow spheres could exactly inherit the metal‐to‐metal ratios of initial LDH precursors, which provided an effective way to control the compositions of oxide shells. This strategy was suitable for preparation of a series of oxide hollow spheres from binary to multi‐component ones, including MgO/Al2O3, MgO/Fe3O4, NiO/Al2O3, and ZnO/NiO/Al2O3.
Stereoselective Synthesis of Optically Active Hydrobenzoins via Asymmetric Hydrogenation of Benzils with Ru(OTf)(TsDPEN)(η6‐cymene) as the Pre‐catalyst
Authors: Huang Xiaofei , Li Naikai , Geng Zhicong , Pan Fengfeng , Wang Xingwang 
Published: August 2012

AbstractOptically active hydrobenzoins are very important building blocks for further derivation of biologically active complexes, natural products, and pharmaceutical compounds. In this paper, A practical approach has been developed for asymmetric hydrogenation of benzils with Ru(OTf)(TsDPEN)(η6‐cymene) as a pre‐catalyst in methanol. Therefore, a series of chiral hydrobenzoins was synthesized in good yields with good to moderate diastereoselectivities and good to excellent enantioselectivities.
Palladium‐Catalyzed N‐Alkylation of Amides and Amines with Alcohols Employing the Aerobic Relay Race Methodology
Authors: Yu Xiaochun , Jiang Lan , Li Qiang , Xie Yuanyuan , Xu Qing 
Published: August 2012

AbstractPossibly because homogeneous palladium catalysts are not typical borrowing hydrogen catalysts and ligands are thus ineffective in catalyst activation under conventional anaerobic conditions, they had not been used in the N‐alkylation reactions of amines/amides with alcohols in the past. By employing the aerobic relay race methodology with Pd‐catalyzed aerobic alcohol oxidation being a more effective protocol for alcohol activation, ligand‐free homogeneous palladiums are successfully used as active catalysts in the dehydrative N‐alkylation reactions, giving high yields and selectivities of the alkylated amides and amines. Mechanistic studies implied that the reaction most probably proceeds via the novel relay race mechanism we recently discovered and proposed.
Highly Efficient Synthesis of Unsymmetrical 3,3′‐Bis(1H‐indol‐3‐yl)methanes in Water
Authors: Lin Hua , Zang Yang , Sun Xingwen , Lin Guoqiang 
Published: August 2012

AbstractA simple and practical approach for the preparation of unsymmetric bis(indolyl)methanes (BIMs) was realized by Lewis acid InBr3‐catalyzed Friedel‐Crafts reaction of indoles with 3‐indolyl‐substituted phthalides in water.
Catalytic, Conjugate Reduction‐Aldol Addition Reaction of β′‐Oxoalkyl α,β‐Unsaturated Carboxylates
Authors: Zheng Aijun , Jiang Lan , Li Zhengning 
Published: August 2012

AbstractIntramolecular conjugate reduction‐aldol addition reactions of β′‐oxoalkyl α,β‐unsaturated carboxylates were performed in the presence of copper catalysts generated in situ from copper salts, phosphine ligands and silanes. Moderate to good yields and high diastereoselectivities were obtained in 15 min to 3 h using bis[(2‐diphenylphosphino)phenyl] ether as the ligand.
Incidence and predictors of venous thromboembolism (VTE) among ambulatory high‐risk cancer patients undergoing chemotherapy in the United States
Authors: Khorana Alok A. , Dalal Mehul , Lin Jay , Connolly Gregory C. 
Published: August 2012

AbstractBACKGROUND:Recent studies suggest that thromboprophylaxis is beneficial in preventing venous thromboembolism (VTE) in cancer outpatients, but this is not widely adopted because of incomplete understanding of the contemporary incidence of VTE and concerns about bleeding. Therefore, the authors examined the incidence and predictors of VTE in ambulatory patients with bladder, colorectal, lung, ovary, pancreas, or gastric cancers.METHODS:Data were extracted from a large health care claims database of commercially insured patients in the United States between 2004 and 2009. Demographic and clinical characteristics of the cancer cohort (N = 17,284) and an age/sex‐matched, noncancer control cohort were evaluated. VTE incidence was recorded during a 3‐month to 12‐month follow‐up period after the initiation of chemotherapy. Multivariate analyses were conducted to identify independent predictors of VTE and bleeding.RESULTS:The mean age of the study population was 64 years, and 51% of patients were women. VTE occurred in 12.6% of the cancer cohort (n = 2170) over 12 months after the initiation of chemotherapy versus 1.4% of controls (n = 237; P < .0001); incidence ranged by cancer type from 19.2% (pancreatic cancer) to 8.2% (bladder cancer). Predictors of VTE included type of cancer, comorbidities (Charlson Comorbidity Index score or obesity), and commonly used specific antineoplastic or supportive care agents (cisplatin, bevacizumab, and erythropoietin).CONCLUSIONS:This large, contemporary, real‐world analysis confirmed high rates of VTE in select patients with solid tumors and suggested that the incidence of VTE is high in the real‐world setting. Awareness of the benefits of targeted thromboprophylaxis may result in a clinically significant reduction in the burden of VTE in this population. Cancer 2013. © 2012 American Cancer Society.
The addition of low‐dose‐rate brachytherapy and androgen‐deprivation therapy decreases biochemical failure and prostate cancer death compared with dose‐escalated external‐beam radiation therapy for high‐risk prostate cancer
Authors: Shilkrut Mark , Merrick Gregory S. , McLaughlin P. William , Stenmark Matthew H. , Abu‐Isa Eyad , Vance Sean M. , Sandler Howard M. , Feng Felix Y. , Hamstra Daniel A. 
Published: August 2012

AbstractBACKGROUND:The objective of this study was to determine whether the addition of low‐dose‐rate brachytherapy or androgen‐deprivation therapy (ADT) improves clinical outcome in patients with high‐risk prostate cancer (HiRPCa) who received dose‐escalated radiotherapy (RT).METHODS:Between 1995 and 2010, 958 patients with HiRPCa were treated at Schiffler Cancer Center (n = 484) or at the University of Michigan (n = 474) by receiving either dose‐escalated external‐beam RT (EBRT) (n = 510; minimum prescription dose, 75 grays [Gy]; median dose, 78 Gy) or combined‐modality RT (CMRT) consisting of 103Pd implants (n = 369) or 125I implants (n = 79) both with pelvic irradiation (median prescription dose, 45 Gy). The cumulative incidences of biochemical failure (BF) and prostate cancer‐specific mortality (PCSM) were estimated by using the Kaplan‐Meier method and Fine and Gray regression analysis.RESULTS:The median follow‐up was 63.2 months (interquartile range, 35.4‐99.0 months), and 250 patients were followed for >8 years. Compared with CMRT, patients who received EBRT had higher prostate‐specific antigen levels, higher tumor classification, lower Gleason sum, and more frequent receipt of ADT for a longer duration. The 8‐year incidence BF and PCSM among patients who received EBRT was 40% (standard error, 38%‐44%) and 13% (standard error, 11%‐15%) compared with 14% (standard error, 12%‐16%; P < .0001) and 7% (standard error 6%‐9%; P = .003) among patients who received CMRT. On multivariate analysis, the hazard ratios (HRs) for BF and PCSM were 0.35 (95% confidence interval [CI], 0.23‐0.52; P < .0001) and 0.41 (95% CI, 0.23‐0.75; P < .003), favoring CMRT. Increasing duration of ADT predicted decreased BF (P = .04) and PCSM (P = .001), which was greatest with long‐term ADT (BF: HR, 0.33; P < .0001; 95% CI, 0.21‐0.52; PCSM: HR, 0.30; P = .001; 95% CI, 0.15‐0.6) even in the subgroup that received CMRT.CONCLUSIONS:In this retrospective comparison, both low‐dose‐rate brachytherapy boost and ADT were associated with decreased risks of BF and PCSM compared with EBRT. Cancer 2013. © 2012 American Cancer Society.
Randomized study of 2 reduced‐intensity conditioning strategies for human leukocyte antigen‐matched, related allogeneic peripheral blood stem cell transplantation
Authors: Blaise Didier , Tabrizi Reza , Boher Jean‐Marie , Le Corroller‐Soriano Anne‐Gaëlle , Bay Jacques‐Olivier , Fegueux Nathalie , Boiron Jean‐Michel , Fürst Sabine , Castagna Luca , Chabannon Christian , Boyer‐Chammard Agnes , Milpied Noël , Labussière‐Wallet Hélène , Faucher Catherine , Bardou Valerie‐Jeanne , Mohty Mohamad , Michallet Mauricette 
Published: August 2012

AbstractBACKGROUND:The optimal intensity of reduced‐intensity conditioning (RIC) before allogeneic hematopoietic stem cell transplantation (allo‐HSCT) remains uncertain.METHODS:In this centrally randomized phase 2 study, the authors compared 2 different strategies of RIC. In total, 139 patients (median age, 54 years; range, 21‐65 years) with hematologic malignancies underwent allo‐HSCT from a human leukocyte antigen‐identical sibling after conditioning combining fludarabine with either busulfan and rabbit antithymocyte‐globulin (BU‐rATG) (n = 69) or total body irradiation (TBI) (n = 70). Postgraft immunosuppression consisted of cyclosporin A in all patients with the addition of mycophenolate‐mophetil after TBI.RESULTS:The median follow‐up was 54 months (range, 26‐88 months). One‐year overall survival rate was identical in both groups. Four patients experienced graft‐failure after TBI. The incidence of grade 2 through 4 acute graft‐versus‐host‐disease was greater after BU‐rATG than after TBI (47% vs 27%; P = .01), whereas no difference was observed with chronic graft‐versus‐host‐disease. The BU‐rATG group had a higher objective response rate (65% vs 46%; P = .05) and a lower relapse rate (27% vs 54%; P < .01). However, the nonrelapse mortality rate was higher after BU‐rATG than after TBI (38% vs 22%; P = .027). At 5 years, the overall and progression‐free survival rates were 41% and 29%, respectively, and did not differ statistically between groups. A detrimental effect on some parameters of quality of life was more pronounced after BU‐rATG, but recovery was identical in both groups. The mean total cost per patient, including the cost to treat disease progression post‐transplantation, did not differ statistically between groups.CONCLUSIONS:Five years after transplantation, the BU‐rATG regimen was associated with greater disease control. However, because of the higher nonrelapse mortality rate, this did not translate into better overall or progression‐free survival. Cancer 2013. © 2012 American Cancer Society.
Enhanced Van der Waals calculations in genetic algorithms for protein structure prediction
Authors: Bonetti Daniel R.F. , Delbem Alexandre C.B. , Travieso Gonzalo , de Souza Paulo Sergio L. 
Published: August 2012

SUMMARYSeveral ab initio computational methods for protein structure prediction have been designed using full‐atom models and force field potentials to describe interactions among atoms. Those methods involve the solution of a combinatorial problem with a huge search space. Genetic algorithms (GAs) have shown significant performance increases for such methods. However, even a small protein may require hundreds of thousands of energy function evaluations making GAs suitable only for the prediction of very small proteins. We propose an efficient technique to compute the van der Waals energy (the greatest contributor to protein stability) speeding up the whole GA. First, we developed a Cell‐List Reconstruction procedure that divides the tridimensional space into a cell grid for each new structure that the GA generates. The cells restrict the calculations of van der Waals potentials to ranges in which they are significant, reducing the complexity of such calculations from quadratic to linear. Moreover, the proposal also uses the structure of the cell grid to parallelize the computation of the van der Waals energy, achieving additional speedup. The results have shown a significant reduction in the run time required by a GA. For example, the run time for the prediction of a protein with 147,980 atoms can be reduced from 217 days to 7 h. Copyright © 2012 John Wiley & Sons, Ltd.
Solar Hydrogen Generation with Wide‐Band‐Gap Semiconductors: GaP(100) Photoelectrodes and Surface Modification
Authors: Kaiser Bernhard , Fertig Dominic , Ziegler Jürgen , Klett Joachim , Hoch Sascha , Jaegermann Wolfram 
Published: August 2012

AbstractGaP, with its large band gap of 2.26 eV (indirect) and 2.78 eV (direct), is a very promising candidate for direct photoelectrochemical water splitting. Herein, p‐GaP(100) is investigated as a photocathode for hydrogen generation. The samples are characterized after each preparation step regarding how their photoelectrochemical behavior is influenced by surface composition and structure using a combination of electrochemical and surface‐science preparation and characterization techniques. The formation of an Ohmic back contact employing an annealed gold layer and the removal of the native oxides using various etchants are studied. It turns out that the latter has a pronounced effect on the surface composition and structure and therefore also on the electronic properties of the interface. The formation of a thin Ga2O3 buffer layer on the p‐GaP(100) surface does not lead to a clear improvement in the photoelectrochemical efficiency, neither do Pt nanocatalyst particles deposited on top of the buffer layer. This behavior can be understood by the electronic structure of these layers, which is not well suited for an efficient charge transfer from the absorber to the electrolyte. First experiments show that the efficiency can be considerably improved by employing a thin GaN layer as a buffer layer on top of the p‐GaP(100) surface.