bluuebunny/crossref_metadata_2025_split huggingface dataset:
A CASSCF/MRCI study of the low‐lying electronic states of the BeS molecule
Authors: De Oliveira‐Filho Antonio G. S. , Alves Tiago V. , Ribas Vladir W. , Ferrão Luiz F. A. , Roberto‐Neto Orlando , Machado Francisco B. C. , Ornellas Fernando R. 
Published: August 2010

AbstractAccurate potential energy curves, dipole moment functions, dissociation energies, and molecular constants for several low‐lying singlet and triplet electronic states of BeS were investigated using the CASSCF/MRCI methodology, and the cc‐pV5Z basis set for beryllium, and the aug‐cc‐pV(5+d)Z set for sulfur. Besides presenting improved results for the three lowest lying states, this study presents the first theoretical characterization of another set of nine excited states so far unknown experimentally. Our results are sufficiently accurate to reliably guide the experimental search and characterization of these states, and also to confirm the experimental assignment of the B
1Σ+ excited state. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Heat transport through a biological membrane—An asymmetric property? Technical issues of nonequilibrium molecular dynamics methods
Authors: Müller Thomas J. , Müller‐Plathe Florian 
Published: August 2010

AbstractTo investigate heat transport across a biological membrane, we performed a series of reverse nonequilibrium molecular dynamics (RNEMD) simulations on a model dipalmitoylphosphatidylcholine (DPPC) bilayer system at the atomistic level. In a detailed analysis of the initially irritating results, we show how and to which extent the RNEMD method (in the special case of an ordered, heterogeneous system, like a bilayer in water) is influenced by simulation conditions. We prove that the interplay between the description of the long range forces and the nonequilibrium algorithm can lead to significant changes in the apparent local thermal conductivity profile across the membrane. As this is the first case reported where the otherwise robust RNEMD results are not directly interpretable, we discuss not only the reasons but also several concepts to handle this effect. Note that this is not a flaw of the RNEMD method but of the simulation framework it is performed in. Therefore, the considerations apply to other equilibrium and nonequilibrium molecular dynamics simulations of the thermal conductivities, too, and care must be taken when heterogeneous systems or interfaces appear in simulations. The complete understanding of the directly obtained results finally allows us to describe the heat flow across the membrane qualitatively. On this basis, we show that the tail–tail interface of the bilayer is the most hindering region for the heat flow, and thus, dominates the overall thermal conductivity of the membrane. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Directional tendencies of halogen and hydrogen bonds
Authors: Shields Zenaida P. , Murray Jane S. , Politzer Peter 
Published: August 2010

AbstractHalogen bonding, RX···B, and hydrogen bonding, RH···B, are electrostatically‐driven noncovalent interactions of covalently‐bonded halogens RX and hydrogens RH with negative sites B. A significant difference between halogen and hydrogen bonding is that the former is typically near‐linear (the R‐X‐B angles are close to 180°), whereas the latter is more likely to be nonlinear (R‐H‐B angles sometimes considerably less than 180°). In this work, we have looked at the properties of several RBr···B and RH···B complexes as functions of these angles. The differences in the directional tendencies in these interactions can be attributed to the presence of nonbonding valence electrons on the bromines, and their absence on hydrogen. We also found that for a given negative site, the halogen and hydrogen bonding interaction energies correlate very well with the positive electrostatic potentials created at it by RX and RH. This attests to the electrostatically‐driven nature of these interactions. Overall, this study provides support for regarding both halogen and hydrogen bonding as subsets of σ‐hole interactions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Energy and density analysis on the H2 molecule from the united atom to dissociation: The Σ, Π, Δ, ϕ, and Γ manifolds
Authors: Corongiu Giorgina , Clementi Enrico 
Published: August 2010

AbstractWe present 140 accurate potential energy curves, PECs, for the Σ, Π, Δ, ϕ, and Γ manifolds for the H2 molecule, mapping all the states with energy below the H ground state. The full configuration interaction, nonrelativistic Born–Oppenheimer computations are performed with large and optimized basis sets of Slater‐type and spherical Gaussian functions; these new basis sets are somewhat larger than those used in recent published studies on the 60 Σ state PECs. The full CI computations are performed twice, with Hartree–Fock and with Heitler–London‐type functions, allowing the identification of the ionic component in the total energy. The computed energies are within 10−5 hartree from the most accurate PECs in literature. We aim (a) at the evaluation of the PECs starting at very short and unexplored internuclear distances (0.01 bohrs) and ending at full dissociation, (b) at the systematic prediction of high excited state PECs dissociating as 1s + 4l and 1s + 5l, and (c) at the characterization of the evolution of the 140 PEC electronic densities from united atom to dissociation. With this work we fill a gap in today literature, which has dealt mainly with low excited states, generally excluding short internuclear distances. The electronic configuration at the united atom persists as dominant configuration well beyond the equilibrium separation, and it switches to that at dissociation often with energy patterns seemingly irregular, in particular when the values of the principal quantum number at dissociation and at the united atom differ by one or more unit. The Hund's singlet‐triplet splitting, which propagates from the united atom to the molecule, is discussed. The singlet and triplet states are rather close in energy in the Π manifolds, and approach degeneracy in the Δ and ϕ manifolds, to become fully degenerate in the Γ manifolds. Discussions on the correlation energy correction, adiabatic correction, spectroscopic constants and on general features of the H2 excited states are presented. The H2 molecule is a system, which—to be understood—needs consideration of both the very short internuclear distances in approaching the united atom and of the very high excited states below H. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Reactivity of polynuclear zinc‐thiolate sites
Authors: Ohanessian Gilles , Picot Delphine , Frison Gilles 
Published: August 2010

AbstractThe proton affinities of a series of mono‐ and polynuclear zinc‐thiolate compounds, mimicking zing finger protein and metallothioneins (MTs) sites, have been investigated by density functional theory calculations. This allows to evaluate the intrinsic nucleophilicity of synthetic and natural zinc‐bound thiolates and to compare their relative reactivities. The site specificity of the experimental thiolate alkylation for the Zn4Cys11clusters in MTs is well reproduced, as well as the relative reactivities of ZnHis2Cys2, ZnHisCys3, and ZnCys4zinc finger sites. Our results also show that terminal thiolates, bound to only one Lewis acid, are more reactive than bridging thiolates. Synthetic inorganic clusters and the Zn4Cys9His2cluster found in a cyanobacterial MT are less reactive than Zn4Cys11and Zn3Cys9clusters in MTs. These results allow discussing the influence of the protein backbone and residues on the reactivity of these natural clusters. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Guanine in water solution: Comprehensive study of hydration cage versus continuum solvation model
Authors: Shukla Manoj K. , Leszczynski Jerzy 
Published: August 2010

AbstractWe report the results of computational investigation of structures and properties of deoxyribonucleic acid base guanine in the isolated and under heavily hydrated conditions. Heavily hydrated condition involves guanine inside the hydrated cage of 65 water molecules. For comparison, results of hydration of guanine with smaller water shells and that in bulk water solution are also presented. Ground state geometries were optimized at the Hartree–Fock and density functional theory (DFT) level using the B3LYP functional. Vertical electronic singlet transitions were computed at the time‐dependent DFT level using the B3LYP optimized geometries. Geometries in the electronic lowest singlet ππ* excited state were optimized at the CIS level of the theory. Effect of bulk water solution was considered using the PCM approach. The standard 6‐311G(d,p) basis set was used in all calculations. The similarity and differences between these two models (bulk water solvation and hydration) in describing the aqueous environment on guanine are also reported. It has been found that hydration with 65 water molecule and PCM solvation both produce similar ground and excited state geometry of guanine. In addition, the possible effect of selective hydration on the excited state dynamics is also discussed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Three‐dimensional localization for the MagneBike inspection robot
Authors: Tâche Fabien , Pomerleau François , Caprari Gilles , Siegwart Roland , Bosse Michael , Moser Roland 
Published: August 2010

AbstractThe MagneBike inspection robot is a climbing robot equipped with magnetic wheels. The robot is designed to drive on three‐dimensional (3D) complexly shaped pipe structures; therefore it is necessary to provide 3D visualization tools for the user, who remotely controls the robot out of sight. The localization system is required to provide a 3D map of the unknown environment and the 3D location of the robot in the environment's map. The localization strategy proposed in this paper consists of combining 3D odometry with 3D scan registration. The odometry model is based on wheel encoders and a three‐axis accelerometer. Odometry enables the tracking of the robot trajectory between consecutive 3D scans and is used as a prior for the scan matching algorithm. The 3D scan registration facilitates the construction of a 3D map of the environment and refines the robot position computed with odometry. This paper describes in detail the implementation of the localization concept. It presents the lightweight, small‐sized 3D range finder that has been developed for the MagneBike. It also proposes an innovative 3D odometry model that estimates the local surface curvature to compensate for the absence of angular velocity inputs. The different tools are characterized in detail based on laboratory and field experiments. They show that the localization concepts reliably track the robot moving in the specific application environment. We also describe various techniques to optimize the 3D scanning process, which is time consuming, and to compensate for the identified limitations. These techniques are useful inputs for the future automatization of the robot's control and optimization of its localization process. © 2010 Wiley Periodicals, Inc.
It was 60 years ago today! Reflections on change in China: A decade framed by two parades
Authors: Lipsher Laurence E. 
Published: August 2010

AbstractThe lyrics below are mine but the tune is “Sgt. Pepper's Lonely Hearts Club Band.” Though you may have been born after this song hit the airwaves, this Beatles standard should be one of those melodies that is indelibly etched in your mind … so sing, and sing it loud:
It was 60 years ago today Chairman Mao, he had his Beijing day So quickly were the viewing stands made To watch the first ever National Day parade! Here comes the People's Army red flag marching band We hope you do enjoy the show! The KMT they've fled to Taiwan isle No war, let's make the country grow! Chairman Mao's red party, unifying China Chairman Mao's red party, watch us grow! © 2010 Wiley Periodicals, Inc.
Physiological responses to temperature and haeme synthesis modifiers in earthworm Lumbricus terrestris (Annelida: Oligochaeta)
Authors: Khan M. A. Q. , Khan Munawwar Ali , Hurlock Peter , Ahmed S. A. 
Published: August 2010

AbstractEarthworms (Lumbricus terrestris) acclimated at 2° and 6°C above their average habitat temperature (10°C) had respectively 15 and 40% higher rate of respiration than those at habitat temperature. At 14°C, the rate of respiration and blood hemoglobin (Hb) concentration both increased by ∼60 and 50%, respectively, of the values at habitat temperature. At higher temperatures the rate of respiration and Hb synthesis started decreasing. At 20–23°C, the respiration and Hb concentration decreased respectively by about 85% and 35% of that at 14°C. Decrease in blood Hb concentration at higher temperatures appeared to be due to the lowering of the activity of blood enzyme δ‐aminolaevulinic acid dehydratase (ALAD). Exposure of 20–23°C‐acclimated pale worms to ALAD inhibitor (lead), lowered the already compromised rate of respiration and blood Hb concentration; while exposure to hexachlorobenzene (HCB, inducer of haeme synthesis) and ferric chloride (enhancer of haeme synthesis) did not overcome the inhibitory effect of high temperature on Hb synthesis. At 20–23°C the affinity of Hb for oxygen also decreased as indicated by the lowering of oxy‐Hb (HbO) concentration in blood. The lowering of concentration of blood Hb and its affinity for oxygen may lower the amount of oxygen delivered to cells, which may limit the level of aerobic metabolism (glycolysis, oxidative phosphorylation), as indicated by an increase in blood glucose concentration and a decrease in in vitro activities of mitochondrial electron transport system components (ETS) namely NADH‐cytochrome c reductase, succinate dehydrogenase, cytochrome c oxidase, and ATPases. Although the oxygen concentration in air, at sea level, does not decrease significantly from 6° to 20–23°C (lack of hypoxia), lowering of both Hb and HbO concentrations by high temperature may cause significant hypoxemia. The latter may lead to inhibition of the activity of muscle mitochondrial respiratory enzymes (ETS). The resulting inhibition of ATP synthesis and hydrolysis may cause deficit of energy needed for peristalsis/fictive locomotion of body and heart muscles (as indicated by a decrease in heart rate) to facilitate diffusion and transport of gases. The upper critical temperature (20–23°C) also slows down the heart rate and causes hyperosmotic stress (hypovolemia). Thus, a rise in soil temperature above 18°C, which inhibits Hb synthesis, Hb oxygenation, and mitochondrial ETS activity, and slows down the heart rate and causes hyperosmotic stress, can make this and higher temperatures lethal to populations of these earthworms, especially in the presence of metabolic inhibitors and respiratory poisons. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Effects of streptomycin on growth of algae Chlorella vulgaris and Microcystis aeruginosa
Authors: Qian Haifeng , Li Jingjing , Pan Xiangjie , Sun Zhengqi , Ye Chengbin , Jin Gongqin , Fu Zhengwei 
Published: August 2010

AbstractStreptomycin is a common contaminant in a variety of industrial and agricultural wastewaters. The available information on the potential toxicity of streptomycin of fresh algae implicated in the treatment of biological wastewater is extremely limited. The objective of this study was to evaluate the effects of streptomycin on physiological indices and photosynthesis‐related gene transcription. The results of short‐term batch bioassays indicated that streptomycin was more sensitive to cyanobacteria than to green algae. The EC50 of streptomycin in Microcystis aeruginosa and Chlorella vulgaris were 0.28 and 20.08 mg L−1, respectively. These selected streptomycin concentrations inhibited algal cell growth and decreased chlorophyll or phycocyanobilin content. Streptomycin also destroyed the overall membrane system, which was speculated from malondialdehyde (MDA) content and electrolyte leakage increasing after streptomycin exposure. Two algae were induced to increase their antioxidant enzyme activities to withstand streptomycin. However, the balance between oxidant substance and antioxidant enzyme was broken, because reactive oxygen species (ROS) content simultaneously increased. Streptomycin inhibited photosynthesis‐related gene transcription in C. vulgaris and M. aeruginosa. Transcript levels of psaB, psbA, and rbcL in C. vulgaris decreased to only 14.5%, 32.2%, and 9.3% of the control, respectively. Similarly, the transcript levels of psaB, psbD, and rbcL in M. aeruginosa decreased markedly in the present of streptomycin. The transcription of these genes was 12.4%, 26.1%, and 28.4% of the control after 0.1 mg L−1 streptomycin exposure, respectively. Our results demonstrate that streptomycin is toxic to fresh algae, affects photosynthesis‐related gene transcription, and blocks electron transport and ROS overproduction. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Assessment of genotoxic effects induced by selected pesticides on RTG‐2 fish cells by means of a modified fast micromethod assay
Authors: Parra Juan Manuel , Sánchez‐Fortún Sebastián , Castaño Argelia 
Published: August 2010

AbstractThe cytotoxic and genotoxic effects induced by alachlor and dichlorvos, two pesticides broadly used, were studied on RTG‐2 fish cell line. As measure of cytotoxicity, neutral red assay was used to determine the cellular viability. Toxicity ranking based on IC50values found that alachlor was more cytotoxic than dichlorvos. DNA damage has been evaluated on RTG‐2 cultures by means of anin vitroassay based on the ability of PicoGreen® fluorochrome to interact preferentially with double‐stranded DNA (dsDNA), and the results indicated that alachlor induced DNA strand breaks at concentrations above 1.52 μg/mL, equivalent to 1/50‐EC50(48), whereas exposures to dichlorvos induced DNA damage only at the maximal concentrations tested 25 μg/mL (1/10‐EC50(48)). These results confirm the suitability of this method for the screening of genotoxic effects of this type of aquatic pollutants, and we suggest their use in hazard assessment for environmental risk procedures. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Bioaccumulation and biochemical markers in feral crab (Carcinus maenas) exposed to moderate environmental contamination—The impact of non‐contamination‐related variables
Authors: Pereira Patrícia , Pablo Hilda de , Subida Maria Dulce , Vale Carlos , Pacheco Mário 
Published: August 2010

AbstractModerate contamination is a challenging scenario for ecotoxicologists because of the occurrence of subtle biomarker responses and the increased relevance of non‐contamination related variables. This investigative biomonitoring study was performed in a moderately contaminated coastal system (Óbidos lagoon, Portugal) to examine winter–summer variations on biochemical responses and accumulated metals inCarcinus maenas, searching for associations with environmental and biological factors. Males and females were collected in three sites: Barrosa (BB) and Bom‐Sucesso (BS) in upper lagoon, and the middle lagoon (ML), closer to the lagoon inlet. Water and sediment were monitored for metals (Cu, Mn, Ni, Cr, Cd). Catalase (CAT), glutathione peroxidase (GPx), glutathioneS‐transferase (GST), total glutathione content (GSHt), lipid peroxidation (LPO), and ethoxyresorufin‐O‐deethylase (EROD), as well as Cu, Mn, Ni, Cr and Cd were measured in the crabs' hepatopancreas. Inter‐site differences, though infrequent, pointed to the presence of crab stressors at BB. This was particularly obvious in summer when higher GST as well as lower GSHtand EROD were found in females, and accompanied by higher Ni accumulation. Seasonal differences of biochemical responses superimposed spatial variations in line with the contrasting winter–summer conditions regarding water quality and, to a lesser extent, with metal bioaccumulation. CAT, GSHt, and LPO were higher in summer, whereas enhancements of GPx and GST were recorded in winter. Winter increases were in agreement with higher availability of metals in water and enhancement of accumulated levels, particularly in females as emphasized by a bioaccumulation index. On the other hand, increases in summer were mainly driven by non‐contamination related factors. Males and females exhibited different patterns of metal accumulation and biochemical responses, with females being more responsive, as confirmed by a general stress index (IBR). Results recommend gender separation in biomonitoring programs using crabs. The integration of biochemical responses into IBR substantiated data interpretation. This is particularly relevant under moderate contamination allowing for better site‐distinction rather than biochemical responses considered individually. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.
Interaction of Water-Soluble CdTe Quantum Dots with Bovine Serum Albumin
Authors: Poderys Vilius , Matulionyte Marija , Selskis Algirdas , Rotomskis Ricardas 
Published: August 2010

AbstractSemiconductor nanoparticles (quantum dots) are promising fluorescent markers, but it is very little known about interaction of quantum dots with biological molecules. In this study, interaction of CdTe quantum dots coated with thioglycolic acid (TGA) with bovine serum albumin was investigated. Steady state spectroscopy, atomic force microscopy, electron microscopy and dynamic light scattering methods were used. It was explored how bovine serum albumin affects stability and spectral properties of quantum dots in aqueous media. CdTe–TGA quantum dots in aqueous solution appeared to be not stable and precipitated. Interaction with bovine serum albumin significantly enhanced stability and photoluminescence quantum yield of quantum dots and prevented quantum dots from aggregating.
Sodium butyrate induces differentiation of gastric cancer cells to intestinal cells via the PTEN/phosphoinositide 3‐kinase pathway
Authors: Bai Zhigang , Zhang Zhongtao , Ye Yingjiang , Wang Shan 
Published: August 2010

AbstractNaB (sodium butyrate) inhibits cell proliferation and induces differentiation in a variety of tumour cells. In this study, we aimed to determine whether NaB induced differentiation and regulated the expression of the mucosal factor MUC2 through the PTEN/PI3K (phosphoinositide 3‐kinase) pathway. BGC823 cells treated with NaB for 24–72 h showed marked inhibition of cell proliferation and alteration in cellular morphology. NaB treatment markedly increased the expression of PTEN and MUC2, but it decreased the expression of PI3K. These effects were enhanced by intervention with PI3K inhibitors and were reduced by intervention with PTEN siRNA. Hence, we conclude that NaB increased PTEN expression, promoted the expression of MUC2 and induced the differentiation of gastric cancer cells through the PTEN/PI3K signalling pathway.