bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions between Keggin Anions in Water: The Higher Their Charge, the Higher Their Condensation? A Simulation Study
Authors: Chaumont Alain , Wipff Georges 
Published: October 2012

AbstractWe report molecular dynamics (MD) simulations of aqueous solutions of Keggin heteropolyacids XWn– nH3O+ (XWn– = [PW12O40]3–, [SiW12O40]4–, and [AlW12O40]5–), the aim of which was to investigate whether the anions increasingly repulse each other in water when their charge increases from –3 to –5. The MD and PMF (potential of mean force) results indicate that this is not the case. All three anions are found to display short XWn–···XWn– contacts (“dimers”), the amount of which increases at increasing concentrations. However, the proportion of dimers follows the sequence SiW4– < PW3– < AlW5–, which is unexpected from interanionic Coulomb forces. The least‐charged anions are mainly attracted by hydrophobic forces, whereas the most charged AlW5– anions afford the highest proportion of dimers through specific interactions with H3O+ counterions. Similar features are observed in two series of fictitious analogues of XWn– (n = 3 to 5): the Sn– spherical anions, and the XWn+ cations (with all atomic charges of XWn– inverted and “H3O–” as counterions). The key role of counterion condensation on the stabilization of the most negatively charged dimers is further demonstrated by comparing Li+ salts to Na+ and Cs+ salts of the different XWn– anions: anion–anion dimerization is found to be highest between AlW5– anions and in the presence of the “hardest” counterions (Li+). Likewise, with Eu3+ multivalent AlW5– counterions condense into a concentrated ionic domain in water. Finally, all three types of XWn– anions are found to adsorb at the aqueous interface with graphite. These findings are important for understanding processes like dimerization, condensation, third phase formation, and the assembly of polyoxometalates and macroions in water or at aqueous interfaces.
Various radical polymerizations of glycerol‐based monomers
Authors: Pham Phuoc Dien , Monge Sophie , Lapinte Vincent , Raoul Yann , Robin Jean Jacques 
Published: October 2012

AbstractThis paper aims at making the state of the art of the radical polymerizations of glycerol‐based monomers, especially (meth)acrylate and vinylic/allylic derivatives. Acrylate and methacrylate derivatives bearing numerous secondary groups like ester, cyclocarbonate, acetal, and urethane were involved in free radical polymerization and radical controlled polymerizations as well as in the photopolymerization. Glycerol‐based monomers bearing a vinylic or an allylic polymerizable group polymerize by acceptor–donor process and produce alternating copolymers. From all these monomers, the synthesis of functionalized polymers was possible, leading to various valuable applications.
Configurational Assignment of Cyclic Bisbibenzyls by HPLC‐CD and Quantum‐Chemical CD Calculations
Authors: Schaumlöffel Anu , Groh Matthias , Knauer Michael , Speicher Andreas , Bringmann Gerhard 
Published: October 2012

AbstractMacrocyclic bisbibenzyls are intriguing natural products that are obtained from liverworts. Recently, they have received growing interest due to the discovery of novel representatives and because of their antitumoral and antifungal activities. Depending on the individual coupling type, these structures can possess one or two biaryl axes, which, with larger ortho substituents or increased ring strain within the macrocycle, leads to the occurrence of configurationally stable atropisomers. Within this work, representatives of the plagiochin and riccardin types, both containing one biaryl unit and one biaryl ether moiety, have been investigated for their stereochemical stabilities and electronic circular dichroism (ECD) by means of HPLC‐UV and HPLC‐CD in combination with quantum‐chemical DFT and ab initio RICC2 calculations. We demonstrate that the computation of the chiroptical properties of such macrocycles is a nontrivial task, because of the presence of charge‐transfer (CT) excitations especially in the riccardin‐type structures, which leads to a failure of DFT methods in the excited‐states calculations, thus necessitating the use of the coupled‐cluster approach for a reliable attribution of the absolute configurations of the enantiomers. In the course of this study, the previous assignments of the absolute configurations of the atropisomers of plagiochin E and riccardin D are revised.
Construction of Chiral Multi‐Functionalized Polyheterocyclic Benzopyran Derivatives by Using an Asymmetric Organocatalytic Domino Reaction
Authors: Guo Zhi‐Wei , Li Xin‐Sheng , Zhu Wei‐Dong , Xie Jian‐Wu 
Published: October 2012

AbstractThe asymmetric domino reaction of various α,α‐dicyano olefins to 3‐nitro‐2H‐chromenes was studied employing readily available cinchona‐derived bifunctional thioureas as organocatalysts. These new transformations were highly regio‐, chemo‐, diastereo‐, and enantioselective simultaneously giving chiral multi‐functionalized polyheterocyclic benzopyran derivatives with multi‐chiral carbon centers.
Mechanism and Scope of the MnIII‐Initiated Oxidation of β‐Ketocarbonyl Compounds: Furan Synthesis
Authors: Wang Chao , Li Zhilong , Ju Yeming , Koo Sangho 
Published: October 2012

AbstractUnless the MnIII‐produced carbon‐radical from β‐ketocarbonyl compounds undergoes smooth intramolecular addition to alkenes, it traps molecular oxygen in the reaction medium to produce a peroxy radical, which reacts with the neighbouring carbonyl group to form 1,2‐dioxetane. Thermal decomposition of 1,2‐dioxetane completes the oxidation to produce α‐oxo ester. This oxidation seems to be general at 50 °C under aerobic conditions, and can be catalytic for MnIII in AcOH with ultrasonic irradiation. Thus, the development of a new synthetic method for diversely substituted furans has been accomplished based on a couple of the MnIII‐initiated domino oxidation of β‐ketocarbonyl compounds with a suitable α‐allylic substitution.
Impact of channel estimation error on fixed‐gain two‐way relay network with user/antenna selection
Authors: Fan Lisheng , Lei Xianfu , Chen Hongbin , Zhou Wen 
Published: October 2012

ABSTRACTThis letter considers a multiuser two‐way relay network with a single fixed‐gain amplify‐and‐forward relay, where there areMantennas at the base station (BS) andNmobile stations. Depending on the channel conditions, one best antenna from BS and one best user are selected to communicate with each other. We study the impact of channel estimation error to the system over Rayleigh fading environments. In particular, a closed‐form expression is obtained for system outage probability. It is found that an error floor appears in the outage probability as long as the channel estimation is imperfect. We further study the power allocation (PA) among the network nodes to minimise the outage probability. Numerical results are presented to evaluate the effects of both channel estimation error and PA on the system performance. Copyright © 2012 John Wiley & Sons, Ltd.
The human sulfatase 2 inhibitor 2,4‐disulfonylphenyl‐tert‐butylnitrone (OKN‐007) has an antitumor effect in hepatocellular carcinoma mediated via suppression of TGFB1/SMAD2 and Hedgehog/GLI1 signaling
Authors: Zheng Xin , Gai Xiaohong , Han Shaoshan , Moser Catherine D. , Hu Chunling , Shire Abdirashid M. , Floyd Robert A. , Roberts Lewis R. 
Published: October 2012

AbstractHuman sulfatase 2 (SULF2) functions as an oncoprotein in hepatocellular carcinoma (HCC) development by promoting tumor growth and metastasis via enhancement of fibroblast growth factor‐2/extracellular signal‐regulated kinase and WNT/β‐catenin signaling. Recent results implicate that SULF2 activates the transforming growth factor beta (TGFB) and Hedgehog/GLI1 pathways in HCC. OKN‐007 is a novel phenyl–sulfonyl compound that inhibits the enzymatic activity of SULF2. To investigate the antitumor effect of OKN‐007 in HCC, we treated Huh7 cells, which express high levels of SULF2, with OKN‐007 and found that it significantly promoted tumor cell apoptosis and inhibited cell proliferation, viability, and migration. To understand the action of OKN‐007 on SULF2, we used Huh7 cells which normally express SULF2 and Hep3B cells that do not normally express SULF2. Utilizing Huh7 cells transfected with short hairpin RNA targeting SULF2 and transfection of Hep3B cells with a SULF2 plasmid to enhance SULF2 expression, we showed that the antitumor activity of OKN‐007 was more pronounced in cells expressing SULF2. Furthermore, in vivo experiments verified that OKN‐007 repressed tumor growth significantly. These results identify SULF2 as an important target of the antitumor effect of OKN‐007. To determine the molecular mechanism of the antitumor effect of OKN‐007, both TGFB1/SMAD and Hedgehog/GLI1 signaling pathway activity were measured by Western blot and SMAD‐ or GLI‐reporter luciferase assays. We found that both signaling pathways were inhibited by OKN‐007. Together, these results show that OKN‐007 can suppress TGFB1/SMAD and Hedgehog/GLI1 signaling via its inhibition of SULF2 enzymatic activity. We conclude that OKN‐007 or more potent derivatives may be promising agents for the treatment of HCC. © 2012 Wiley‐Periodicals, Inc.
PARENTAL INCOME AND THE DYNAMICS OF HEALTH INEQUALITY IN EARLY CHILDHOOD—EVIDENCE FROM THE UK
Authors: Kruk Kai Eberhard 
Published: October 2012

ABSTRACTRecent research documents that socioeconomic health inequality has its origins in early childhood, that is, children from high‐income families have better health than their peers from low‐income families. In this article, we investigate the determinants of the evolution of socioeconomic health inequality in the UK. We analyze the relation between household income and both the prevalence and the consequences of adverse health conditions by following up infants throughout early childhood. We find evidence for the hypothesis that parental income operates through two different channels: it reduces the likelihood of incurring certain illnesses and it cushions the consequences of health conditions. Our results also indicate that a higher household income increases the probability that children fully recover from some diseases within a given period. Copyright © 2012 John Wiley & Sons, Ltd.
Direct effect of dasatinib on proliferation and cytotoxicity of natural killer cells in in vitro study
Authors: Uchiyama Takayoshi , Sato Naoya , Narita Miwako , Yamahira Akie , Iwabuchi Minami , Furukawa Tatsuo , Sone Hirohito , Takahashi Masuhiro 
Published: October 2012

AbstractLymphocytosis predominantly due to natural killer (NK) cells has been reported in nearly a half of chronic myelogenous leukemia (CML) patients who were being treated with dasatinib. Besides, dasatinib‐treated patients with lymphocytosis have a better prognosis than patients without lymphocytosis. In order to elucidate the effects of dasatinib on the proliferation of lymphocyte subset, dasatinib was added to the culture of peripheral blood mononuclear cells with IL‐2 (lymphokine‐activated killer culture) or a low dose of IL‐2 with zoledronate (γδ T‐cell culture). In both culture conditions, NK cells were increased in both percentage and absolute number in the culture with dasatinib compared with control culture without dasatinib. The increase of NK cells was dose dependent of dasatinib in the range of 2–25 nM. NK cell cytotoxicity of cultured cells with dasatinib was demonstrated to be superior to control cells without dasatinib in cytotoxicity assay using EGFP‐transfected K562 cells as target cells. The present study suggested that lymphocytosis in dasatinib‐treated CML patients is at least partly associated with a direct effect of dasatinib to stimulate the proliferation of NK cells. Favourable prognosis in patients with dasatinib‐induced lymphocytosis might be associated with the effects of dasatinib to potentiate NK cytotoxicity in vivo. Copyright © 2012 John Wiley & Sons, Ltd.
A mixed‐methods assessment of sexual and gender‐based violence in eastern Democratic Republic of Congo to inform national and international strategy implementation
Authors: Scott Jennifer , Polak Suzanne , Kisielewski Michael , McGraw‐Gross Mary , Johnson Kirsten , Hendrickson Miel , Lawry Lynn 
Published: October 2012

SUMMARYContextNational and international strategies were implemented in eastern Democratic Republic of Congo (DRC) to address sexual and gender‐based violence (SGBV).ObjectivesThe objective was to assess community attitudes of SGBV and health facility capacity to address SGBV in eastern DRC.Design and settingThe design and setting are as follows: a cross‐sectional, population‐based cluster survey of 998 adults in eastern DRC territories, a convenience sample of 27 adults using semi‐structured directed interviews, qualitative data from 37 focus groups conducted in three health zones, assessment of 64 health facilities and a comparative analysis of SGBV strategies.Main outcome measuresThe main outcome measures opinions regarding SGBV prevention and justice and health facility capacity to address SGBV.ResultsThe majority of respondents favored the legal system over community mediation to obtain justice for SGBV. However, 61.1% (95% CI, 51.8–70.5%) of SGBV survivors reported being forced to accept community mediation. Among SGBV survivors, 81.2% (95% CI, 74.5–87.8%) reported no available mental health care. Less than half of all respondents reported access to a hospital, clinic or pharmacy. The analyses and facility assessment reinforce the need to improve SGBV care.ConclusionsMixed methodologies point to the complexities of addressing SGBV, assess key elements of SGBV prevention, justice and response, and may ultimately inform national and international strategies. Copyright © 2012 John Wiley & Sons, Ltd.
Biodistribution of intact fluorescent CdSe/CdS/ZnS quantum dots coated by mercaptopropionic acid after intravenous injection into mice
Authors: Loginova Yana F. , Kazachkina Natalia I. , Zherdeva Victoria V. , Rusanov Alexander L. , Shirmanova Marina V. , Zagaynova Elena V. , Sergeeva Ekaterina A. , Dezhurov Sergey V. , Wakstein Maxim S. , Savitsky Alexander P. 
Published: October 2012

AbstractSemiconductor quantum dots (QD) have been widely used for fluorescent bioimaging. However their biosafety has attracted increasing attention, since the data about their in vivo behavior in biological systems are still limited. In this paper we have investigated the short‐ and long‐term biodistribution of intact fluorescent CdSe/CdS/ZnS QD coated by 3‐mercaptopropionic acid in mice. The results showed that intravenously injected QD accumulated mainly in the lungs, liver and spleen and were retained in these tissues for over 22 days. QD caused signs of acute toxicity in mice including death. The investigated QD possibly caused vascular thrombosis. The results of a toxicological assay indicated that some histopathological changes occurred in the lung tissue after the injection of QD. Our study highlights the need for careful evaluation of QD safety before their use in biological applications. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discontinuation of denosumab and associated fracture incidence: Analysis from the Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) Trial
Authors: Brown Jacques P , Roux Christian , Törring Ove , Ho Pei-Ran , Beck Jensen Jens-Erik , Gilchrist Nigel , Recknor Christopher , Austin Matt , Wang Andrea , Grauer Andreas , Wagman Rachel B 
Published: October 2012

Abstract
Osteoporosis is a chronic disease and requires long-term treatment with pharmacologic therapy to ensure sustained antifracture benefit. Denosumab reduced the risk for new vertebral, nonvertebral, and hip fractures over 36 months in the Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) trial. Whereas discontinuation of denosumab has been associated with transient increases in bone remodeling and declines in bone mineral density (BMD), the effect on fracture risk during treatment cessation is not as well characterized. To understand the fracture incidence between treatment groups after cessation of investigational product, we evaluated subjects in FREEDOM who discontinued treatment after receiving two to five doses of denosumab or placebo, and continued study participation for ≥7 months. The off-treatment observation period for each individual subject began 7 months after the last dose and lasted until the end of the study. This subgroup of 797 subjects (470 placebo, 327 denosumab), who were evaluable during the off-treatment period, showed similar baseline characteristics for age, prevalent fracture, and lumbar spine and total hip BMD T-scores. During treatment, more placebo-treated subjects as compared with denosumab-treated subjects sustained a fracture and had significant decreases in BMD. During the off-treatment period (median 0.8 years per subject), 42% versus 28% of placebo- and denosumab-treated subjects, respectively, initiated other therapy. Following discontinuation, similar percentages of subjects in both groups sustained a new fracture (9% placebo, 7% denosumab), resulting in a fracture rate per 100 subject-years of 13.5 for placebo and 9.7 for denosumab (hazard ratio [HR] 0.82; 95% confidence interval [CI], 0.49–1.38), adjusted for age and total hip BMD T-score at baseline. There was no apparent difference in fracture occurrence pattern between the groups during the off-treatment period. In summary, there does not appear to be an excess in fracture risk after treatment cessation with denosumab compared with placebo during the off-treatment period for up to 24 months. © 2013 American Society for Bone and Mineral Research.
Binding structures of tri‐N‐acetyl‐β‐glucosamine in hen egg white lysozyme using molecular dynamics with a polarizable force field
Authors: Zhong Yang , Patel Sandeep 
Published: October 2012

AbstractLysozyme is a well‐studied enzyme that hydrolyzes the β‐(1,4)‐glycosidic linkage of N‐acetyl‐β‐glucosamine (NAG)n oligomers. The active site of hen egg‐white lysozyme (HEWL) is believed to consist of six subsites, A‐F that can accommodate six sugar residues. We present studies exploring the use of polarizable force fields in conjunction with all‐atom molecular dynamics (MD) simulations to analyze binding structures of complexes of lysozyme and NAG trisaccharide, (NAG)3. MD trajectories are applied to analyze structures and conformation of the complex as well as protein–ligand interactions, including the hydrogen‐bonding network in the binding pocket. Two binding modes (ABC and BCD) of (NAG)3 are investigated independently based on a fixed‐charge model and a polarizable model. We also apply molecular mechanics with generalized born and surface area (MM‐GBSA) methods based on MD using both nonpolarizable and polarizable force fields to compute binding free energies. We also study the correlation between root‐mean‐squared deviation and binding free energies of the wildtype and W62Y mutant; we find that for this prototypical system, approaches using the MD trajectories coupled with implicit solvent models are equivalent for polarizable and fixed‐charge models. © 2012 Wiley Periodicals, Inc.
Solvent‐driven symmetry of self‐assembled nanocrystal superlattices—A computational study
Authors: Kaushik Ananth P. , Clancy Paulette 
Published: October 2012

AbstractThe preference of experimentally realistic sized 4‐nm facetted nanocrystals (NCs), emulating Pb chalcogenide quantum dots, to spontaneously choose a crystal habit for NC superlattices (Face Centered Cubic (FCC) vs. Body Centered Cubic (BCC)) is investigated using molecular simulation approaches. Molecular dynamics simulations, using united atom force fields, are conducted to simulate systems comprised of cube‐octahedral‐shaped NCs covered by alkyl ligands, in the absence and presence of experimentally used solvents, toluene and hexane. System sizes in the 400,000–500,000‐atom scale followed for nanoseconds are required for this computationally intensive study. The key questions addressed here concern the thermodynamic stability of the superlattice and its preference of symmetry, as we vary the ligand length of the chains, from 9 to 24 CH2 groups, and the choice of solvent. We find that hexane and toluene are “good” solvents for the NCs, which penetrate the ligand corona all the way to the NC surfaces. We determine the free energy difference between FCC and BCC NC superlattice symmetries to determine the system's preference for either geometry, as the ratio of the length of the ligand to the diameter of the NC is varied. We explain these preferences in terms of different mechanisms in play, whose relative strength determines the overall choice of geometry. © 2012 Wiley Periodicals, Inc.
A detailed investigation on the global minimum structures of mixed rare‐gas clusters: Geometry, energetics, and site occupancy
Authors: Marques Jorge M. C. , Pereira Francisco B. 
Published: October 2012

AbstractWe performed a global minimum search of mixed rare‐gas clusters by applying an evolutionary algorithm (EA), which was recently proposed for binary atomic systems (Marques and Pereira, Chem. Phys. Lett. 2010, 485, 211). Before being applied to the potentials used in this work, the EA was further tested against results previously reported for the ArNXe38−N clusters and several new putative global minima were discovered. We employed either simple Lennard‐Jones (LJ) potentials or more realistic functions to describe pair interactions in ArNKr38−N, ArNXe38−N, and KrNXe38−N clusters. The long‐range tail of the pair‐potentials shows some influence on the energetic features and shape of the structure of clusters. In turn, core–shell type structures are mostly observed for global minima of the binary rare‐gas clusters, for both accurate and LJ potentials. However, the long‐range tail of the potential may have influence on the type of atoms that segregate on the surface or form the core of the cluster. While relevant differences for the preferential site occupancy occur between the two potentials for ArNKr38−N (for N > 21), the type of atoms that segregate on the surface for ArNXe38−N and KrNXe38−N clusters is unaffected by the accuracy of the long‐range part of the interaction in almost all cases. Moreover, the global minimum search for model‐potentials in binary systems reveals that the surface‐site occupancy is mainly determined by the combination of two parameters: the size ratio of the two types of particles forming the cluster and the minimum‐energy ratio corresponding to the pair‐interactions between unlike atoms. © 2012 Wiley Periodicals, Inc.
Insights into the dynamics of evaporation and proton migration in protonated water clusters from Large‐scale Born–Oppenheimer direct dynamics
Authors: Rybkin Vladimir V. , Simakov Anton O. , Bakken Vebjørn , Reine Simen , Kjærgaard Thomas , Helgaker Trygve , Uggerud Einar 
Published: October 2012

AbstractLarge‐scale on‐the‐fly Born–Oppenheimer molecular dynamics simulations using recent advances in linear scaling electronic structure theory and trajectory integration techniques have been performed for protonated water clusters around the magic number (H2O)nH+, for n = 20 and 21. Besides demonstrating the feasibility and efficiency of the computational approach, the calculations reveal interesting dynamical details. Elimination of water molecules is found to be fast for both cluster sizes but rather insensitive to the initial geometry. The water molecules released acquire velocities compatible with thermal energies. The proton solvation shell changes between the well‐known Eigen and Zundel motifs and is characterized by specific low‐frequency vibrational modes, which have been quantified. The proton transfer mechanism largely resembles that of bulk water but one interesting variation was observed. © 2012 Wiley Periodicals, Inc.