bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical study of mechanism of extraction reaction between silylene carbene and its derivatives and ethylene oxide
Authors: Lu Xiu Hui , Che Xin , Han Jun Feng , Shi Le Yi , Lian Zhen Xia 
Published: May 2010

AbstractThe mechanism of the oxide extraction reaction between singlet silylene carbene and its derivatives [X2Si = C: (X = H, F, Cl, CH3)] and ethylene oxide has been investigated with density functional theory, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. The energies of the different conformations are calculated by B3LYP/6‐311G(d,p) method. From the potential energy profile, it can be predicted that the reaction pathway of this kind consists two steps, the first step is the two reactants firstly form an intermediate (INT) through a barrier‐free exothermic reaction; the second step is the INT then generates a product via a transition state (TS). This kind reaction has similar mechanism, when the silylene carbene and its derivatives [X2Si = C: (X = H, F, Cl, CH3)] and ethylene oxide close to each other, the shift of 2p lone electron pair of O in ethylene oxide to the 2p unoccupied orbital of C in X2Si = C: gives a p → p donor–acceptor bond, thereby leading to the formation of INT. As the p → p donor–acceptor bond continues to strengthen (that is, the CO bond continues to shorten), the INT generates product (P + C2H4) via TS. It is the substituent electronegativity, which mainly affects the extraction reactions. When the substituent electronegativity is greater, the energy barrier is lower, and the reaction rate is greater. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Sequence‐dependent proton‐transfer reaction in stacked GC pair III: The influence of proton transfer to conductivity
Authors: Nakanishi Yasuyuki , Matsui Toru , Shigeta Yasuteru , Kitagawa Yasutaka , Saito Toru , Kataoka Yusuke , Kawakami Takashi , Okumura Mitsutaka , Yamaguchi Kizashi 
Published: May 2010

AbstractWe have computed current–voltage character of natural DNA and its proton‐transferred structure by scattering theory based on density functional theory. The current is not observed if the electron path contains only hydrogen bonding such as one base pair. The current becomes larger if the electron path contains π–π stacking molecule such as two base pairs. We also found that the conductivity of pseudo‐ion pair (C+G−/G−C+), which is derived from proton‐transfer reaction in CG/GC, differs from that of the original structure. On the other hand, the current changes dramatically if the electrode connects to guanine or cytosine, which can be explained by the difference of electron affinities. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Is fullerene C60 large enough to host an aromatic molecule?
Authors: Mazurek Aleksander P. , Sadlej‐Sosnowska Nina 
Published: May 2010

AbstractThe endohedral complex of fullerene with benzene was studied with computational chemistry methods. The changes of structural parameters, such as bond lengths of host and guest and volume increments accompanying complex formation, were investigated, as well as the transfer of electron density between host and guest. The results obtained with three DFT functionals, which were recently designed for weak interactions, were compared. A three‐centered hydrogen bond between H atom of benzene and two atoms of fullerene was found. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A new property of atom energies
Authors: Pearson Ralph G. 
Published: May 2010

AbstractA proof is given that the total nuclear‐electron attraction energy should be constant for all the light atoms, when calculated by various trial wave functions. If hydrogenic wave functions for effective nuclear charges are picked as standards, it is easy to calculate the value of this energy. This constraint should be added to the usual constraints (minimum energy and the virial theorem) of the variation method. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Molecular frame photoelectron angular distributions for H2 ionization by single and trains of attosecond XUV laser pulses
Authors: Sanz‐Vicario J. L. , Pérez‐Torres J. F. , Morales F. , Plésiat E. , Martín F. 
Published: May 2010

AbstractThe delayed autoionization of H2 doubly excited states into channels of different inversion symmetry gerade and ungerade is investigated by using pulses of attosecond duration (isolated or packed in trains), linearly polarized along the molecular axis. It has been shown in previous work, by using XUV laser pulses with durations of 4 fs or longer, that the molecular frame photoelectron angular distributions (MFPAD) associated with the dissociative channel H+ + H(nℓ) are not symmetric with respect to the inversion center of the molecule. In contrast, the MFPADs become symmetric for shorter fs pulses. Here we show that, although this is still the case for pulses of attosecond duration, the combination of two of these pulses with a controlled time delay may still lead to asymmetric MFPADs. From the analysis of the time evolution of the calculated MFPADs, we propose a way to elucidate autoionization lifetimes of molecular resonant states. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2462–2471, 2010
Numerical evidence of two aligned conical intersections induced by the Renner effect in bent C2H cation
Authors: Halász G. J. , Vibók Á. 
Published: May 2010

AbstractCharacterizing and localizing conical intersections1 are important for the control of molecular processes. In an earlier work (see, e.g., Halász et al., J Chem Phys 2007 126, 154309), applying topological phase consideration, we showed, that the Renner effect in polyatomic molecules with more than three nuclei is necessarily accompanied by a so called symmetry‐allowed conical intersection. By using a perturbational approach Vértesi and Englman (J Phys B: At Mol Opt Phys 2008 41, 025102) pointed out that not only one as it was revealed by us, but also two aligned conical intersections will be created in the slightly bent Renner–Teller tetra‐atomic radical cation C2H. The aim of this present work is to support this finding both by symmetry arguments and by ab initio calculations. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
The subsystem functional scheme: The Armiento‐Mattsson 2005 (AM05) functional and beyond
Authors: Mattsson Ann E. , Armiento Rickard 
Published: May 2010

AbstractThe subsystem functional scheme (Kohn and Mattsson, Phys Rev Lett 1998, 81, 3487; Armiento and Mattsson Phys Rev B 2002, 66, 165117) is a recently proposed framework for constructing exchange‐correlation density‐functionals for use in density functional theory based calculations. The fundamental principle is to describe the physics in a real material by mapping onto model systems that exhibit the characteristic physics in each separate part of the real system. The local density approximately (LDA) functional can be seen as a subsystem functional: in all parts of the real material the assumption is that the needed physics is well described by the uniform electron gas model system. It is well known that this assumption is very accurate for surprisingly large classes of materials. The Armiento–Mattsson 2005 (AM05) (Armiento and Mattsson, Phys Rev B 2005, 72, 085108; Mattsson and Armiento, Phys Rev B 2009, 79, 155101) functional takes this a step further by distinguishing between two separate types of regions in a real material, one type that is assumed to be well described by the uniform electron gas, and the other type of region assumed to be well described by a surface model system. AM05 gives a consistent improvement over LDA. One important consequence of the subsystem functional scheme is that it is known what physics is included in a functional. Based on the performance of AM05 for a number of different systems, we discuss where the model systems included are enough and when additional physics need to be included in a new functional. Improvement of AM05 is possible by fine‐tuning the details in the construction. But a new major step in accuracy improvement is only expected if new physics is integrated in a functional via an additional model system. We discuss what type of physics would be needed and what model systems could be used for this next step beyond AM05. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
An examination of change profiles in reusable and non‐reusable software systems
Authors: Gupta Anita , Cruzes Daniela , Shull Forrest , Conradi Reidar , Rønneberg Harald , Landre Einar 
Published: May 2010

AbstractThis paper reports on an industrial case study in a large Norwegian Oil and Gas company (StatoilHydro ASA) involving a reusable Java‐class framework and two applications that use that framework. We analyzed software changes from three releases of the reusable framework, called Java Enterprise Framework (JEF), and two applications reusing the framework, called Digital Cargo File (DCF) and Shipment and Allocation (S&A). On the basis of our analysis, we found the following: (1) Profiles of change types for the reused framework and the applications are similar, specifically, perfective changes dominate significantly. (2) Although on observing the mean value adaptive changes are more frequent and are active longer in JEF and S&A, these systems went through less refactoring than DCF. For DCF, we saw that preventive changes were more frequent and were active longer. (3) Finally, we found that designing for reuse seems to lead to a long‐term payoff in relation to non‐reusable software systems. Copyright © 2010 John Wiley & Sons, Ltd.
A comparative investigation of the packing and flow properties of sweet potato (Ipomoea batatas) starches and their potential use in solid dosage formulations
Authors: Riley Cliff K. , Adebayo Sarafadeen A. 
Published: May 2010

AbstractA comparative evaluation of the flow and packing properties of starch products extracted from three sweet potato (Ipomoea batatas) cultivars grown in Jamaica was done with a view to assessing their suitability as excipients in solid dosage formulations. Significant differences were observed in the properties of the starches obtained from the different sweet potato cultivars (p<0.05). The mean granular diameter ranged from 13.4 ± 0.42 (Eustace) to 20 ± 0.85 µm (Clarendon). Clarendon starch was found to be the least cohesive and bulkiest with Compressibility Index (CI) of 32.69 ± 0.28%, angle of internal flow (θi) of 12.70 ± 0.12° and maximum volume reduction (a) of 35.65 ± 1.02%, while Eustace was the most cohesive and least bulky with CI values of 37.74 ± 1.06%, θi of 19.68 ± 0.22°, and a of 43.60 ± 0.95%. The starch powders had similar bulk densities and packing fraction (p>0.05). All other fundamental properties calculated from the projected mean diameter including surface mean diameter (dvs), Heywood equivalent diameter (de) and specific surface (Sw) varied significantly (p<0.05) in a cultivar‐dependent manner but with no consistent pattern of variation among cultivars. The results indicate intravarietal variations in the packing and cohesive properties of the starches studied which may be a result of variations in the fundamental properties of the granules. These differences in properties may prove significant when predicting the behaviour of starches during handling and pharmaceutical formulations.
Determination of the mass‐specific distribution of the substituents in cationic starch derivatives
Authors: Radosta Sylvia , Ulbrich Marco , Vorwerg Waltraud 
Published: May 2010

AbstractThe mass‐specific charge distribution in molar mass fractions of cationic starch derivatives was investigated. The molar mass fractions were produced by semi‐preparative SEC (SP‐SEC). The derivatives were cut into an amylopectin‐rich fraction F1, an intermediate fraction F2, containing low molar mass amylopectin and high molar mass amylose, and an amylose‐rich fraction F3. The weight‐average molar mass (Mw) and molar mass distribution (MMD) of the fractions were determined by SEC with multi‐angle laser light scattering (SEC‐MALLS). The mass‐specific charge of each fraction was calculated from the consumption of anionic titrant solution using polyelectrolyte titration (PET) in combination with particle charge detection (PCD). The difference in substituent distribution between the fractions was tested by the Student's t‐test. The weight‐average molar mass of the starch derivatives was not dependent on the degree of substitution (DS) or the derivatization process. Depending on the DS value or derivatization process, different substituent distributions were observed. The results for the mass‐specific charge distribution in different molar mass fractions of cationic starch derivatives with graded DS between 0.015 and 0.130 from the slurry process were discussed. The heterogeneity of substituent distribution decreased with increasing DS of the starch derivative. This was the case for samples from both the slurry and semi‐dry processes. The heterogeneity of derivatization was highest for low DS samples up to DS 0.03, with the amylopectin‐rich fraction incorporating more charges than the amylose‐rich fraction. This was more pronounced for the sample from the slurry process than from the semi‐dry process.
Rheological and functional properties of flours from banana pulp and peel
Authors: Bertolini Andréa C. , Bello‐Pérez Luis A. , Méndez‐Montealvo Guadalupe , Almeida Claudia A. S. , Lajolo Franco 
Published: May 2010

AbstractUnripe banana flour can be an alternative to minimize post‐harvest loss and to increase the aggregate value of banana fruit. Flour from unripe banana is rich in phytosterols and resistant starch, being proposed as health food. Flours from unripe banana peel and pulp were evaluated on their composition, phytosterols content, thermal and rheological properties, and pasting profiles. High amounts of β‐sitosterol, campesterol, and stigmasterol were found in flour from banana peel. These samples showed lower viscosity values of pasting profiles, lower energy enthalpy on gelatinization, and higher temperature of gelatinization than those ones from pulp. Anti‐oxidant treatment of fruits with citric acid does not change pasting profiles of flours from pulp, but resulted in slight increase in viscosity, suggesting that structure of starch could be modified by acidification.
Simplified Synthesis and Structural Study of { Ta6Br12} Clusters
Authors: Sokolov Maxim N. , Abramov Pavel A. , Mikhailov Maxim A. , Peresypkina Eugenia V. , Virovets Alexander V. , Fedin Vladimir P. 
Published: May 2010

AbstractDirect reaction of stoichiometric amounts of KBr, tantalum and bromine at 720 °C, followed by extraction and crystallization gives Ta6Br14·7H2O (1). This compound slowly aquates into [(Ta6Br12)(H2O)6]2+, which crystallized as mixed Cs+/Br– (2), Cl– (3) and SO42– (4) salts. In Bu4NBr melt, 1 undergoes oxidation into (Bu4N)2[(Ta6Br12)Br6] (5). Reaction of 1 with dimethylsulfoxide also induces oxidation of the { Ta6Br12} 2+ core into { Ta6Br12} 4+, and the corresponding complex [(Ta6Br12)(dmso)2Cl4]·iPrOH·4.8H2O (6) was isolated and structurally characterized. Molecular and crystal structures for 2–6 were determined.
Synthesis, Crystal Structures, and Vibrational Spectra of Novel Azidopalladates of the Alkali Metals Cs2[Pd(N3)4] and Rb2[Pd(N3)4]·2/3H2O
Authors: Afyon Semih , Höhn Peter , Somer Mehmet 
Published: May 2010

AbstractThe transparent dark orange compounds Cs2[Pd(N3)4] and Rb2[Pd(N3)4]·2/3H2O are synthesized by reaction of the respective binary alkali metal azides with K2PdCl4 in aqueous solutions. According to single‐crystal X‐ray diffraction investigations, the novel ternary azidopalladates(II) crystallize in the monoclinic space group P21/c (no. 14) with a = 705.7(2) pm, b = 717.3(2) pm, c = 1125.2(5) pm, β = 104.58(2)°, mP30 for Cs2[Pd(N3)4] and a = 1041.4(1) pm, b = 1292.9(2) pm, c = 1198.7(1) pm, β = 91.93(1)°, mP102 for Rb2[Pd(N3)4]·2/3H2O, respectively. Predominant structural features of both compounds are discrete [PdII(N3)4]2– anions with palladium in a planar coordination by nitrogen, but differing in point group symmetries., The vibrational spectra of the compounds are analyzed based on the idealized point group C4h of the spectroscopically relevant unit, [Pd(N3)4]2– taking into account the site symmetry splitting due to the symmetry reduction in the solid phase.
Paradoxes of dissipation‐induced destabilization or who opened Whitney's umbrella?
Authors: Kirillov O.N. , Verhulst F. 
Published: May 2010

AbstractThe paradox of destabilization of a conservative or non‐conservative system by small dissipation, or Ziegler's paradox (1952), has stimulated an ever growing interest in the sensitivity of reversible and Hamiltonian systems with respect to dissipative perturbations. Since the last decade it has been widely accepted that dissipation‐induced instabilities are closely related to singularities arising on the stability boundary. What is less known is that the first complete explanation of Ziegler's paradox by means of the Whitney umbrella singularity dates back to 1956. We revisit this undeservedly forgotten pioneering result by Oene Bottema that outstripped later findings for about half a century. We discuss subsequent developments of the perturbation analysis of dissipation‐induced instabilities and applications over this period, involving structural stability of matrices, Krein collision, Hamilton‐Hopf bifurcation, and related bifurcations.
Surgical management of pancreatic necrosis: towards lesser and later
Authors: Cheung Moon‐Tong , Li Wing‐Hong , Kwok Philip Chong‐Hei , Hong Jeffrey Kam‐Fai 
Published: May 2010

AbstractBackground/purposeOur aim was to determine the overall success rate and survival rate with respect to the timing of intervention in the management of pancreatic necrosis. The use of minimally invasive pancreatic necrosectomy was also examined.MethodsThis was a retrospective study carried out in a tertiary referral hospital. The subjects were all patients who suffered from acute pancreatic necrosis with emergency interventions from January 2001 to December 2007. For outcome measures, special emphasis was placed on the overall success rate and survival rate with respect to the timing of intervention. The success rate of percutaneous pancreatic necrosectomy (PCPN) was examined.ResultsA total of 26 patients with pancreatic necrosis were studied. The overall mortality rate was 26.9% and the rate was significantly higher in those patients who had earlier intervention (before 6 weeks). Eleven patients had PCPN. There were 2 failures due to PCPN in the early phase; 2 had partial success, while the procedure was completely successful to remove all the necrotic tissues in the other 7 patients.ConclusionsWith a multidisciplinary approach, particularly with sophisticated intensive care, most patients with pancreatic necrosis can survive the initial phase. Open surgery should be limited to simple drainage and laparostomy to relieve the abdominal tension. Active intervention preferably should be delayed until the necrosis has become walled off, when a variety of minimally invasive maneuvers, notably percutaneous necrosectomy, can be offered to remove the debris. The surgical management of pancreatic necrosis should change towards a strategy of “lesser and later”.
Sonographic demonstration of wall thickness of the gallbladder in pediatric patients with pancreatico‐biliary maljunction
Authors: Sugai Michihiro , Ishido Keinosuke , Endoh Masaaki , Hada Ryukichi , Munakata Hirohumi 
Published: May 2010

AbstractBackgroundSonographic demonstration of extramural and intrapancreatic junction of the pancreatic and bile ducts, pathognomonic for pancreatico‐biliary maljunction (PBM), is not easy in pediatric patients. We measured sonographic thickness of the gallbladder (GB) and retrospectively examined correlation of it with PBM.MethodsTwenty‐seven children with PBM were examined with conventional ultrasonography (US). All patients underwent hepaticojejunostomy, and resected GB were studied in histological examination. Preoperative extracorporeal US measured gallbladder wall thickness, and abnormal GB wall was defined 3 mm or more in thickness.ResultsThey consisted of 8 males and 19 females, ranging in age from 2 months to 11 years. The thickness of the GB wall was more than 3 mm in 18: 10 with smooth thickness and 8 with non‐uniform thickness. The thickness of GB wall was found in 16 (84.2%) of the 19 patients more than 1 year of age. The difference between sonographic and macroscopic measurements of the wall thickness was less than 1 mm in 24 (89%) of the 27 patients.ConclusionUS measurement of gallbladder wall thickness can be a screening test more than 1 year of age for PBM.
Comparison of the outcomes between anatomical resection and limited resection for single hepatocellular carcinomas no larger than 5 cm in diameter: a single‐center study
Authors: Yamazaki Osamu , Matsuyama Mitsuharu , Horii Katsuhiko , Kanazawa Akishige , Shimizu Sadatoshi , Uenishi Takahiro , Ogawa Masao , Tamamori Yutaka , Kawai Shuichi , Nakazawa Kazunori , Otani Hiroshi , Murase Junya , Mikami Shinichi , Higaki Ikko , Arimoto Yuichi , Hanba Hiroyuki 
Published: May 2010

AbstractBackground/PurposeLiver resection is a widely preferred treatment modality for hepatocellular carcinomas (HCCs). This study aimed to compare the survival impact of anatomical resection with that of limited resection, in patients with single HCCs no larger than 5 cm in diameter.MethodsA cohort study was carried out on 209 consecutive patients who underwent hepatic resection for a single HCC no larger than 5 cm in diameter between January 1994 and March 2007 at Osaka City General Hospital.ResultsThe cumulative 5‐year overall survival and disease‐free survival rates in the anatomical resection group (n = 111) were 71 and 40%, respectively, both of which were significantly better than the 48 and 25% seen in the limited resection group (n = 98) (P = 0.0043 andP = 0.0232, respectively). Better effects of the anatomical resection on both overall and disease‐free survival were seen in patients having HCC larger than 2 cm in diameter and in patients with moderately or poorly differentiated HCC. But no significant difference in either overall or disease‐free survival was seen between the groups in patients with a HCC 2 cm or less in diameter or in the patients with well‐differentiated HCC. Using Cox's regression model, anatomical resection was confirmed to be an independent favorable factor for both overall and disease‐free survival.ConclusionsAnatomical resection is therefore recommended for histologically advanced single HCCs ranging from 2 to 5 cm in diameter.