bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chiral Discrimination by Vibrational Spectroscopy Utilizing Local Modes
Authors: Kraka Elfi , Freindorf Marek , Cremer Dieter 
Published: January 2013

ABSTRACTChiral discrimination of homochiral and heterochiral H‐bonded complexes is a challenge for both experimentalists and computational chemists. It is demonstrated that a two‐pronged approach based on far‐infrared vibrational spectroscopy and the calculation of local mode frequencies facilitates the chiral discrimination of H‐bonded dimers. The local H‐bond stretching frequencies identify the strongest H‐bonds and by this the dominating chiral diastereomer. This is shown in the case of peroxide, trioxide, hydrazine, glycidol, and butan‐2‐ol dimers as well as propylene oxide…glycidol complexes investigated with the help of second‐order Møller–Plesset perturbation, coupled cluster, and density functional theory calculations where, in the latter case, the ωB97X‐D functional was used for an improved description of H‐bonding. In some cases, additional intermolecular interactions overrule the important role of H‐bonding, which is found by calculating chirodiastaltic energies. Chirality 25:185–196, 2013. © 2013 Wiley Periodicals, Inc.
Spatiotemporal analysis of climate variability (1971–2010) in spring and summer on the Loess Plateau, China
Authors: Zhang Baoqing , Wu Pute , Zhao Xining , Gao Xiaodong 
Published: January 2013

AbstractBy using the Variable Infiltration Capacity model with Palmer Drought Severity Index (VIC‐PDSI) model and Standardized Precipitation Index (SPI), spatiotemporal trends of climate variation during the main growing seasons for plants of Loess Plateau between 1971 and 2010 were detected and characterized. The VIC‐PDSI model is established by combining the VIC model with PDSI. The simulation results and the grids system of VIC were applied to substitute for the two‐layer bucket‐type model to do the hydrological accounting, which could improve the physical mechanism of PDSI and expand its application range. Our results suggest that the climate of the study area has experienced a drying and warming trend during the past four decades. Apart from some individual years and regions, there was a perpetuation of water deficit over the Plateau both in spring and summer. The drought frequency increased from southeast to northwest in spring, while the drought frequency decreased from southeast to northwest in summer. The climate in the southern part of the Loess Plateau, accounting for 23.3% of the study region, showed a significant drying and warming trend in spring over the past four decades. The climate variability detected by VIC‐PDSI model shows good agreement with that monitored by SPI. Since a large part of the study region frequently suffered from water shortage during the main growing seasons for plants, people living in such drought‐prone areas should take measures to prevent the negative effects on agricultural production, reforestation, and regional food security caused by drought. Copyright © 2013 John Wiley & Sons, Ltd.
Electronic structure of the S1 state in methylcobalamin: Insight from CASSCF/MC‐XQDPT2, EOM‐CCSD, and TD‐DFT calculations
Authors: Kornobis Karina , Kumar Neeraj , Lodowski Piotr , Jaworska Maria , Piecuch Piotr , Lutz Jesse J. , Wong Bryan M. , Kozlowski Pawel M. 
Published: January 2013

AbstractThe methylcobalamin cofactor (MeCbl), which is one of the biologically active forms of vitamin B12, has been the subject of many spectroscopic and theoretical investigations. Traditionally, the lowest‐energy part of the photoabsorption spectrum of MeCbl (the so‐called α/β band) has been interpreted as an S0→S1 electronic transition dominated by π→π* excitations associated with the CC stretching of the corrin ring. However, a more quantitative band‐shape analysis of the α/β spectral region, along with circular dichroism (CD), magnetic CD, and resonance Raman data, has revealed the presence of a second electronic transition that involves the CoCMe bond weakening. Conversely, the lowest‐energy excitations based on transient absorption spectroscopy measurements have been interpreted as metal‐to‐ligand charge transfer (MLCT) transitions. To resolve the existing controversy about the interpretation of the S1 state of MeCbl, calculations have been performed using two independent ab initio wavefunction‐based methods. These include the modified variant of the second‐order multiconfigurational quasi‐degenerate perturbation theory (MC‐XQDPT2), using complete active space self‐consistent field orbitals, and the equation‐of‐motion coupled‐cluster singles and doubles (EOM‐CCSD) approach using restricted Hartree–Fock orbitals. It is shown that both ab initio methods provide a consistent description of the S1 state as having an MLCT character. In addition, the performance of different types of functionals, including hybrid (B3LYP, MPW1PW91, TPSSh), generalized‐gradient‐approximation‐type (GGA‐type) (BP86, BLYP, MPWPW91), meta‐GGA (TPSS), and range‐separated (CAM‐B3LYP, LC‐BLYP) approaches, has been examined and the results of the corresponding time‐dependent density functional theory calculations have been benchmarked against the MC‐XQDPT2 and EOM‐CCSD data. The hybrid functionals support the interpretation in which the S1 state represents a π→π* transition localized on corrin, while pure GGA, meta‐GGA, and LC‐BLYP functionals produce results consistent with the MLCT assignment. © 2013 Wiley Periodicals, Inc.
Monte Carlo configuration interaction applied to multipole moments, ionization energies, and electron affinities
Authors: Coe Jeremy P. , Taylor Daniel J. , Paterson Martin J. 
Published: January 2013

AbstractThe method of Monte Carlo configuration interaction (MCCI) (Greer, J. Chem. Phys. 1995a, 103, 1821; Tong, Nolan, Cheng, and Greer, Comp. Phys. Comm. 2000, 142, 132) is applied to the calculation of multipole moments. We look at the ground and excited state dipole moments in carbon monoxide. We then consider the dipole of NO, the quadrupole of N2 and of BH. An octupole of methane is also calculated. We consider experimental geometries and also stretched bonds. We show that these nonvariational quantities may be found to relatively good accuracy when compared with full configuration interaction results, yet using only a small fraction of the full configuration interaction space. MCCI results in the aug‐cc‐pVDZ basis are seen to generally have reasonably good agreement with experiment. We also investigate the performance of MCCI when applied to ionisation energies and electron affinities of atoms in an aug‐cc‐pVQZ basis. We compare the MCCI results with full configuration interaction quantum Monte Carlo (Booth and Alavi, J. Chem. Phys. 2010, 132, 174104; Cleland, Booth, and Alavi, J. Chem. Phys. 2011, 134, 024112) and “exact” nonrelativistic results (Booth and Alavi, J. Chem. Phys. 2010, 132, 174104; Cleland, Booth, and Alavi, J. Chem. Phys. 2011, 134, 024112). We show that MCCI could be a useful alternative for the calculation of atomic ionisation energies however electron affinities appear much more challenging for MCCI. Due to the small magnitude of the electron affinities their percentage errors can be high, but with regards to absolute errors MCCI performs similarly for ionisation energies and electron affinities. © 2013 Wiley Periodicals, Inc.
NMR shielding constants of CuX, AgX, and AuX (X = F, Cl, Br, and I) investigated by density functional theory based on the Douglas–Kroll–Hess Hamiltonian
Authors: Yoshizawa Terutaka , Sakaki Shigeyoshi 
Published: January 2013

AbstractTwo‐component relativistic density functional theory (DFT) with the second‐order Douglas–Kroll–Hess (DKH2) one‐electron Hamiltonian was applied to the calculation of nuclear magnetic resonance (NMR) shielding constant. Large basis set dependence was observed in the shielding constant of Xe atom. The DKH2‐DFT‐calculated shielding constants of I and Xe in HI, I2, CuI, AgI, and XeF2 agree well with those obtained by the four‐component relativistic theory and experiments. The Au NMR shielding constant in AuF is extremely more positive than in AuCl, AuBr, and AuI, as reported recently. This extremely positive shielding constant arises from the much larger Fermi contact (FC) term of AuF than in others. Interestingly, the absolute values of the paramagnetic and the FC terms are considerably larger in CuF and AuF than in others. The large paramagnetic term of AuF arises from the large d‐components in the Au dπ –F pπ and Au sdσ–F pσ molecular orbitals (MOs). The large FC term in AuF arises from the small energy difference between the Au sdσ + F pσ and Au sdσ–F pσ MOs. The second‐order magnetically relativistic effect, which is the effect of DKH2 magnetic operator, is important even in CuF. This effect considerably improves the overestimation of the spin‐orbit effect calculated by the Breit–Pauli magnetic operator. © 2013 Wiley Periodicals, Inc.
Theoretical study of ionization and one‐electron oxidation potentials of N‐heterocyclic compounds
Authors: Sviatenko Liudmyla K. , Gorb Leonid , Hill Frances C. , Leszczynski Jerzy 
Published: January 2013

AbstractA number of density functionals was utilized to predict gas‐phase adiabatic ionization potentials (IPs) for nitrogen‐rich heterocyclic compounds. Various solvation models were applied to the calculation of difference in free energies of solvation of oxidized and reduced forms of heterocyclic compounds in acetonitrile (AN) for correct reproduction of their standard oxidation potentials. We developed generally applicable protocols that could successfully predict the gas‐phase adiabatic ionization potentials of nitrogen‐rich heterocyclic compounds and their standard oxidation potentials in AN. This approach is supported by a MPW1K/6‐31+G(d) level of theory which uses SMD(UA0) approximation for estimation of solvation energy of neutral molecules and PCM(UA0) model for ionized ones. The mean absolute derivation (MAD) and root mean square error (RMSE) of the current theoretical models for IP are equal to 0.22 V and 0.26, respectively, and for oxidation potentials MAD = 0.13 V and RMSE = 0.17. © 2013 Wiley Periodicals, Inc.
Comparison of thermodynamic integration and Bennett acceptance ratio for calculating relative protein‐ligand binding free energies
Authors: de Ruiter Anita , Boresch Stefan , Oostenbrink Chris 
Published: January 2013

AbstractThe performances of Bennett's acceptance ratio method and thermodynamic integration (TI) for the calculation of free energy differences in protein simulations are compared. For the latter, the standard trapezoidal rule, Simpson's rule, and Clenshaw‐Curtis integration are used as numerical integration methods. We evaluate the influence of the number and definition of intermediate states on the precision, accuracy, and efficiency of the free energy calculations. Our results show that non‐equidistantly spaced intermediate states are in some cases beneficial for the TI methods. Using several combinations of softness parameters and the λ power dependence, it is shown that these benefits are strongly dependent on the shape of the integrand. Although TI is more user‐friendly due to its simplicity, it was found that Bennett's acceptance ratio method is the more efficient method. It is also the least dependent on the choice of the intermediate states, making it more robust than TI. © 2013 Wiley Periodicals, Inc.
Efficient production of polymalic acid from raw sweet potato hydrolysate with immobilized cells of Aureobasidium pullulans CCTCC M2012223 in aerobic fibrous bed bioreactor
Authors: Zan Zhanquan , Zou Xiang 
Published: January 2013

AbstractBACKGROUNDPolymalic acid (PMA) is a water‐soluble polyester with many attractive properties for biomedical application. Its monomer L‐malic acid is widely used in the food industry and is also a potential C4 platform chemical. Hydrolysate of raw sweet potato as a low‐cost renewable feedstock was applied for the production of PMA by immobilized Aureobasidium pullulans cells in an aerobic fibrous bed bioreactor system (AFBB).RESULTSUnder the initial hydrolysate sugar concentration 120 g L‐1, yeast extract 5 g L‐1, and citrate 7.5 g L‐1, PMA production in a shake flask was improved. Comparison of the kinetics of fed‐batch immobilized‐cell fermentation using the AFBB with those of batch or fed‐batch free‐cell fermentation in a 5 L fermentor showed that immobilized‐cell fermentation gave much higher PMA production and productivity. The maximum PMA production and productivity in AFBB were 57.5 g L‐1 and 0.34 g L‐1 h, which was 30.6% and 21.4% higher than that in free‐cell mode.CONCLUSIONRaw sweet potato is an efficient renewable feedstock for PMA fermentation. This present work demonstrated the great potential of AFBB and renewable feedstocks for the economical production of PMA and malic acid at industrial scale. © 2013 Society of Chemical Industry
Extraction and separation of thorium and rare earths from nitrate medium with p‐phosphorylated calixarene
Authors: Lu Youcai , Bi Yanfeng , Bai Yan , Liao Wuping 
Published: January 2013

AbstractBackgroundThorium is a natural radioactive element which is often associated in different minerals with rare earth elements (REs). In order to satisfy application for nuclear fuel, thorium should be separated from REs and other elements. Calixarene derivatives have been proved to be excellent extractants towards thorium and REs. In this study, a p‐phosphorylated calixarene derivative was applied for extraction and separation of thorium and REs.Resultsp‐phosphorylated calix[4]arene, 5,11,17,23‐tetra(diethoxyphosphoryl)‐ 25,26,27,28‐tetrapropyloxy‐calix[4]arene (L), exhibits good selectivity towards thorium which is extracted into the organic phase as Th(NO3)4·3 L. The thermodynamic functions, ΔH, ΔG, and ΔS have been calculated as 5.55 kJ mol−1, −57.28 kJ mol−1 and 210.84 J mol−1 K−1, respectively. The salting‐out agents (NaNO3 and KNO3) can weaken the separation of Th and Yb but barely affects the separation of Th and La or Gd.ConclusionThe extraction of thorium with the calixarene derivative occurs with a neutral extraction mechanism and the extraction reaction of thorium is an endothermic process. This ligand exhibits high extraction ability towards thorium over a wide range of acidity while the extraction of REs changes more with the solution acidity. Added salts can affect the separation of thorium and REs. This ligand may be used to separate thorium from REs under appropriate conditions. © 2013 Society of Chemical Industry
Sustainability analysis and benchmarking of olive mill wastewater treatment methods
Authors: Zagklis Dimitris P. , Arvaniti Eleni C. , Papadakis Vagelis G. , Paraskeva Christakis A. 
Published: January 2013

AbstractA large number of publications are available in the literature regarding olive mill wastewater treatment methods. However, none of the proposed methods can be considered as a best available method in terms of its effectiveness, and its environmental and economic impact. Using a literature survey, data were collected and evaluated in order for a sustainability and benchmarking analysis to be developed. Physicochemical, biological and advanced oxidation methods were evaluated and judged in terms of their effectiveness, environmental impact and cost. Effectiveness of each method was estimated in terms of COD and phenolic compounds reduction, environmental impact in terms of CO2 production, while for the economic impact the operational costs were taken into account. Finally, a procedure is suggested for selection of the most appropriate method based on user preferences (in terms of effectiveness, environmental impact and cost). The present analysis showed that the most effective processes in terms of organics reduction are membrane filtration, electrolysis, supercritical water oxidation and photo‐Fenton. Lower environmental impact was found with anaerobic digestion, coagulation and lime processes, while the lowest cost category involves biocomposting and membrane filtration, thanks to the exploitation of byproducts (biocompost and phenolic compounds, respectively). © 2013 Society of Chemical Industry
Effect of sub‐ and super‐critical CO2 pretreatment on conformation and catalytic properties evaluation of two commercial enzymes of CALB and Lipase PS
Authors: Liu Yun , Chen Dawei , Wang Shihui 
Published: January 2013

AbstractBACKGROUNDIt is vitally important to understand the effect of sub‐/super‐critical CO2 pretreatment on enzyme conformation and its activity, which should improve the understanding of enzymatic biotransformation applications in nonaqueous media. This study evaluated the effect of sub‐/super‐critical CO2 treatment, including pressure (6 and 10 MPa), exposure time (20, 30 and 150 min) and temperature (35 and 40 °C), on the conformation (e.g. 1D, 2D and 3D structures) and catalytic properties (e.g. residual activity, kinetics constants (Km and Vmax), activation energies (Eα), thermo‐stability and organic solvent tolerance) of two commercial enzymes, CALB and lipase PS in their solution forms.RESULTSCompared with the blank control, the 1D structure of both treated lipases was unchanged, whereas their 2D and 3D structures were altered to some extent. The highest relative activities were 105% and 116% for CALB and lipase PS, respectively. For CALB, Vmax/Km value significantly increased, while for lipase PS, Vmax/Km value was almost constant. Both treated enzymes showed high thermo‐stability with recovery of enzyme activity up to 76% and 80%, respectively. Also, both treated enzymes presented high organic solvent tolerance.CONCLUSIONSIt was speculated that 2D, 3D structure alterations were probably responsible for the satisfactory catalytic properties of enzymes treated with sub‐/super‐critical CO2. © 2013 Society of Chemical Industry
Quantitative analysis of LED effects on edible mushroom Pleurotus eryngii in solid and submerged cultures
Authors: Wu Jiun‐Yan , Chen Hua‐Bing , Chen Mei‐Jheng , Kan Shu‐Chen , Shieh Chwen‐Jen , Liu Yung‐Chuan 
Published: January 2013

AbstractBackgroundExopolysaccharides (EPS) from mushrooms have many health properties such as anti‐tumor effect and immunoenhancing activity. Light‐emitting diodes (LEDs) with various light wavelengths (red, yellow, green, blue and white) were applied to study the effects on mycelial growth and EPS production of Pleurotus eryngii.ResultsIn solid‐state culture, red and yellow light showed stimulatory effects on P. eryngii hyphal growth. In submerged culture, darkness was the best condition for biomass production. The highest EPS production was obtained when using blue light, where the EPS production and specific EPS production rates were 455 mg L‐1 and 79.8 mg g‐1 dry‐cell‐weight day‐1, respectively.ConclusionThe results indicate that a decreasing biomass and an increasing EPS yield in P. eryngii culture were obtained with decreased light wavelength. © 2013 Society of Chemical Industry
Dislocations in nanostructured two‐phase Fe30Ni20Mn20Al30
Authors: Wu X. , Baker I. 
Published: January 2013

ABSTRACTIn a previous study, the dislocations in Fe30Ni20Mn25Al25 (at. %), which consist of 50 nm wide alternating b.c.c. and B2 phases, were shown to have a/2<111> Burgers vectors after room temperature deformation. The dislocations were found to glide in pairs on both {110} and {112} slip planes and were relatively widely separated in the b.c.c. phase, where the dislocations were uncoupled, and closely spaced in the B2 phase, where the dislocations were connected by an anti‐phase boundary. In this article, we analyze the dislocations in the two ∼5 nm‐wide B2 phases in a related two‐phase alloy Fe30Ni20Mn20Al30, with compositions Fe‐23Ni‐21Mn‐24Al and Fe‐39Ni‐12Mn‐34Al, compressed to ∼3% strain at a strain rate 5 × 10−4 s−1 at 873 K (the lowest temperature at which substantial plastic flow was observed). It is shown that slip occursby the glide of a<100> dislocations. A review of the literature suggests that the differences in the observed slip vector between these B2 phases could be due to the differences in composition, differences in deformation temperature, or possibly both. Microsc. Res. Tech. 76:263–267, 2013. © 2013 Wiley Periodicals, Inc.
Response of mice connective tissue to three different endodontic materials
Authors: Kurita Lucio Mitsuo , Cavalcante Roberta Barroso , Gurgel‐Filho Eduardo Diogo , De‐Deus Gustavo André , Ximenes Ana Beatriz , Da Silva Emmanuel João Nogueira Leal 
Published: January 2013

ABSTRACTThe aim of this study was to evaluate the biocompatibility of mineral trioxide aggregate (MTA) Bio and Portland cement (PC) and compare with those of ProRoot MTA. Polyethylene tubes were filled with materials and placed into dorsal subcutaneous connective tissue of Wistar albino rats. After 7, 30, and 60 days after the surgical procedure, the implants with the surrounding tissue were removed. Tissue samples were subjected to histological processing, and sections were stained with hematoxylin and eosin. Sections were evaluated for the intensity of inflammation, predominant cell type, presence of fibrous capsule and granulation tissue. Data were submitted to Kruskal‐Wallis test at a significant level of P ≤ 0.05. No statistical differences were observed at any evaluated condition among tested materials (P > 0.05). Statistically significant differences were observed between mean inflammatory scores, cell types and granulation tissue of the same material in different experimental periods (P < 0.05). Can be concluded that biocompatibility of MTA bio and PC were comparable with that of ProRoot MTA. Microsc. Res. Tech. 76:311–315, 2013. © 2013 Wiley Periodicals, Inc.
Diaphragm morphology of Guinea pig (Cavia porcellus)
Authors: Lessa Thais Borges , da Fonseca Erika T. , de Abreu Dilayla Kelly , Rodrigues Marcio Nogueira , Bertassoli Bruno Machado , de Oliveira e Silva Fernanda Menezes , Ambrósio Carlos Eduardo 
Published: January 2013

ABSTRACTThe diaphragm is the main respiratory muscle. Along with other respiratory muscles, the diaphragm is responsible for the muscular contraction that generates the respiratory cycle and, as a consequence, the gaseous interchanges in the lungs. Guinea pigs (Cavia porcellus Linnaeus 1758) are largely used as experimental animals in many biology applications due to their easy management, low cost, and docile behavior. As the diaphragm exerts important effects on lung physiology and function, this study aimed at investigating the morphological characteristics of the muscle, through macroscopic, microscopic, and scanning electron microscopy to add reference data for future studies. We observed a “U”‐shaped tendineous center and its morphology was similar to other mammals. These results cooperate with the descriptive and comparative anatomy of mammals, besides can be used as control data for areas of surgery and stem cells. Microsc. Res. Tech. 76:316–320, 2013. © 2013 Wiley Periodicals, Inc.
Skeletal ontogeny in basal scleractinian micrabaciid corals
Authors: Janiszewska Katarzyna , Jaroszewicz Jakub , Stolarski Jarosław 
Published: January 2013

AbstractCover illustration. Skeleton of extant micrabaciid scleractinian coral Letepsammia franki Owens, 1994 (holotype USNM75638, Indian Ocean, Durban, 138 m). In this issue of the Journal of Morphology Janiszewska et al. study the skeletal ontogeny of Micrabaciidae, one of two modern basal scleractinian lineages using serial microcomputed tomography sections and scanning electron micrographs. See pp. 243–257 for a new interpretation of the septal development of this group of screactinian corals.