bluuebunny/crossref_metadata_2025 huggingface dataset:
A biobehavioral theoretical framework based on the mechanism of cellular aging for nursing interventions to promote autonomic balance
Authors: Kim Nahyun , Park Jooyeon
Published: May 2024

Purpose: This study reviewed the pathophysiological mechanisms of cellular aging caused by psychological stress and aimed to establish a biobehavioral theoretical framework for nursing interventions to promote autonomic balance based on these mechanisms.Methods: A comprehensive literature review was conducted.Results: A review of the literature showed that the stress response increases the secretion of catecholamines and glucocorticoids, resulting in a greater allostatic load. This load induces inflammatory reactions and oxidative stress, shortening telomere length and damaging mitochondrial DNA, which can lead to cellular aging. Based on this mechanism, a biobehavioral theoretical framework for nursing interventions was established. This framework focuses on delaying or inhibiting the cellular aging process by acting on the stress response stage and improving autonomic balance.Conclusion: According to the proposed biobehavioral theoretical framework, stress-relieving nursing interventions may act on the mechanism of cellular aging caused by stress responses. We believe that this framework could expand our understanding of the biobehavioral aspects of stress and would facilitate efforts to use biomarkers to evaluate the effectiveness of stress-related nursing interventions at the cellular level.
Influence of the coexistence of visual impairment, hearing impairment, and masticatory discomfort on the quality of life of middle-aged adults: an analysis based on the 2019 and 2020 Korea National Health and Nutrition Examination Survey
Authors: Kim Jeong-Eun , Kim Yun-Hee
Published: May 2024

Purpose: Visual impairment, hearing impairment, and masticatory discomfort each influence quality of life (QoL). However, little is known regarding the impact of their coexistence on QoL. Therefore, we aimed to investigate the influence of the coexistence of visual impairment, hearing impairment, and masticatory discomfort on QoL among middle-aged adults aged 40-64.Methods: This study involved a secondary data analysis utilizing the data from years 1 and 2 of the eighth Korea National Health and Nutrition Examination Survey. To evaluate the influence of the coexistence of visual impairment, hearing impairment, and masticatory discomfort on QoL, we conducted a complex sample hierarchical multiple regression analysis.Results: When visual impairment, hearing impairment, and masticatory discomfort coexisted, the QoL was significantly lower than in individuals without any of these conditions.Conclusion: The coexistence of visual impairment, hearing impairment, and masticatory discomfort was negatively correlated with QoL. Therefore, it is important to prepare for old age through appropriate health management during middle age.
Factors influencing the level of performance of patient safety nursing activities among hospital nurses
Authors: Beak Hyun-Ju , Shin Gisoo
Published: May 2024

Purpose: This study investigated the performance of patient safety activities among hospital nurses and aimed to identify the factors influencing their performance of these activities.Methods: It employed a descriptive survey design, targeting 131 nurses currently working in hospitals. The data collection involved posting a guide to the study on an online social network for nurses (NURSECAPE) and recruiting nurses who understood the content and agreed to participate in the survey. The survey was conducted through a self-reporting method via a URL provided to research participants, and the data collection period was from August 11 to September 11, 2019.Results: The results revealed that 46.6% of the participants had experienced patient safety incidents, with falls being the most common. The factors influencing the performance of patient safety nursing activities among the participants were found to be the type of medical institution, community orientation, and environmental suitability in organizational health. These factors explained 38.5% of the variance.Conclusion: Based on these findings, it appears crucial to explore strategies for improving organizational health tailored to the characteristics of each hospital to facilitate better performance of patient safety activities among hospital nurses. Furthermore, subsequent studies are needed to objectively evaluate the adequacy of patient safety activity performance according to the size of the hospital.
A new species of Vallisneria L. for Western Australia and recircumscription of V. triptera S.W.L.Jacobs & K.Frank
Authors: Jobson Richard W , Dunning Luke
Published: May 2024

Vallisneria kristinae R.W.Jobson & Dunning (Hydrocharitaceae) is described as a new species endemic to North Kimberley, Western Australia. It was previously included within the Northern Territory species V. triptera S.W.L.Jacobs & K.A.Frank. Here it is distinguished from that species based on its overall smaller size and weakly-winged fruit capsules. We also find strong genetic differentiation with accessions sampled from across the entire distribution of both taxa. We present a phylogeny based on nuclear ITS and plastid trnK 5′ intron data that also includes all Australian species of Vallisneria. Along with a redescription of V. triptera s. str., diagnostic features are illustrated, a taxonomic key containing all Australian species is provided, and distribution, habitat, and conservation status are discussed.
Cultivating Resilience: Multiple Case Study of School Heads’ Leadership in Integrated Senior High Schools
Authors: Galorio Ian Jake N. , Bauyot Marleonie M.
Published: May 2024

School leaders must be resilient in order to navigate the always shifting challenges in the field of education. This study employed a qualitative multiple case study, having three (3) distinct cases aimed to explore the perspectives of the school heads on resilient leadership in integrated senior high schools of Division of Davao de Oro. There were three (3) participants and six (6) informants underwent in-depth interviews. Participants were chosen through a purposive sampling technique. Each data was analyzed through thematic analysis and cross-case analysis. Case 1’s unique characteristics were resource management and optimization, hierarchical communication and strategic delegation, and crisis management and contingency planning. Participant experiences were complex stakeholder management, innovative problem-solving, and resilience amidst bureaucratic challenges. In times of challenges, the coping mechanism was structured decision-making processes delegation and team empowerment professional support networks. The policy recommendations were promotion of interpersonal communication skills, development of community engagement strategies, and investment in staff well-being programs. Further, Case 3’s unique characteristics were the following: strategic financial management and sustainability, stakeholder engagement and partnerships, brand differentiation and market positioning. The experiences were cultivating philanthropic relationships, navigating parental expectations, and ensuring financial sustainability. The coping mechanisms were strategic partnerships and fundraising initiatives, ethical leadership and values integration, and self-care and well-being practices while the policy recommendations were introduction of ethics and values integration policies, creation of leadership succession plans, and investment in infrastructure and technology. Moreover, cross-case analysis shows each case about distinct characteristics and commonalities such as strategic vision and planning, effective communication and collaboration, and resource management and optimization. Each case has distinct experiences, the common themes were resourcefulness and creativity, and community engagement and collaboration. Their coping mechanisms were effective leadership practices and ethical leadership and well-being. Their policy recommendations were leadership development policies and data-informed policies. This suggests that resilient leadership was crucial for school heads in managing and leading integrated senior high schools, despite the challenges and circumstances they faced in their workplace. Both teachers and learners benefit from the leadership styles promoted by the school heads.
Inclination effects on wave characteristics in annular gas–liquid flows
Authors: Al‐Sarkhi A. , Sarica C. , Magrini K.
Published: April 2011

Measurements of wave characteristics have been conducted in a 0.0762 m internal diameter (ID) pipe at inclinations of 0°, 10°, 20°, 45°, 60°, 75°, and 90° from horizontal. Wave celerity and frequency are very strongly dependent on modified Lockhart–Martinelli parameter, X*, and the inclination angle. Wave amplitude increases with increasing liquid film thickness at the bottom of the pipe. Wave amplitude depends on liquid film thickness for any pipe diameter, surface tension, and viscosity. Strouhal number (dimensionless wave frequency) decreases with increasing X*. Effect of pipe diameter, surface tension, and liquid viscosity on the liquid film Reynolds number, ReLF, was studied. ReLF variation with X* is not sensitive to the surface tension and less sensitive to the pipe diameter. However, ReLF is very sensitive to the viscosity of the flowing liquid. Correlations for wave celerity, amplitude, frequency, and liquid film Reynolds number are proposed. © 2011 American Institute of Chemical Engineers AIChE J, 2012
A particle‐scale index in the quantification of mixing of particles
Authors: Chandratilleke G. R. , Yu A. B. , Bridgwater J. , Shinohara K.
Published: April 2011

Discrete element method (DEM) is a useful tool for obtaining details of mixing processes at a particle scale. It has been shown to satisfactorily describe the flow structure developed in bladed mixers. Here, the advantage is taken of the microstructure gained from DEM to evaluate how best to quantify the microstructure created by mixing. A particle‐scale mixing index (PSMI) is defined based on coordination numbers to represent the structure of a particle mixture. The mixture quality is then analyzed qualitatively and quantitatively in three different ways: a macroscopic mixing index based on the conventional approach, coordination number, and PSMI. Their effectiveness is examined based on DEM data generated for different particle loading arrangements and binary mixtures of particles with various volume fractions, size ratios, and density ratios. Unlike the two other methods, PSMI reveals in a straightforward manner whether a binary mixture of different particles is mixing or segregating over time, while being able to detect particle‐scale structural changes accompanying the mixing or segregation processes in all the mixtures investigated. Moreover, PSMI is promising in that it is not influenced by the size and number of samples, which afflict conventional mixing indexes. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Enhanced lipid and biodiesel production from glucose‐fed activated sludge: Kinetics and microbial community analysis
Authors: Mondala Andro H. , Hernandez Rafael , French Todd , McFarland Linda , Santo Domingo Jorge W. , Meckes Mark , Ryu Hodon , Iker Brandon
Published: April 2011

An innovative approach to increase biofuel feedstock lipid yields from municipal sewage sludge via manipulation of carbon‐to‐nitrogen (C:N) ratio and glucose loading in activated sludge bioreactors was investigated. Sludge lipid and fatty acid methyl ester (biodiesel) yields (% cell dry weight, CDW) were enhanced via cultivation in activated sludge bioreactors operated at high initial C:N ratio (≥40:1) and glucose loading (≥40 g L−1). Under C:N 70, 60 g L−1 glucose loading, a maximum of 17.5 ± 3.9 and 10.2 ± 2.0% CDW lipid and biodiesel yields, respectively, were achieved after 7 d of cultivation. The cultured sludge lipids contained mostly C16C18 fatty acids, with oleic acid consistently accounting for 40–50% of the total fatty acids. Microbial composition in activated sludge exposed to C:N 70 shifted toward specific gammaproteobacteria, suggesting their relevance in lipid production in wastewater microbiota and potential value in biofuel synthesis applications. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Cancer in Noonan, Costello, cardiofaciocutaneous and LEOPARD syndromes
Authors: Kratz Christian P. , Rapisuwon Suthee , Reed Helen , Hasle Henrik , Rosenberg Philip S.
Published: April 2011

Noonan syndrome (NS), Costello syndrome (CS), cardiofaciocutaneous syndrome (CFCS), and LEOPARD syndrome (now also referred to as Noonan syndrome with multiple lentigines or NSML) are clinically overlapping dominant disorders that are caused by mutations in RAS signaling pathway genes. The spectrum of cancer susceptibility in this group of disorders has not been studied in detail. We identified more than 1900 cases of NS, CS, CFCS, or NSML reported in the literature between 1937 and 2010; 88 cancers were reported. The most common cancers reported in 1051 NS subjects were neuroblastoma (n = 8), acute lymphoblastic leukemia (n = 8), low grade glioma (n = 6), and rhabdomyosarcoma (n = 6). These associations are biologically plausible, given that somatic RAS pathway mutations are known to occur in these specific cancers. In addition, 40 childhood cases of myeloproliferative disease were described in individuals with NS, several of whom experienced a benign course of this hematologic condition. We confirmed the previously described association between CS and cancer in 268 reported individuals: 19 had rhabdomyosarcoma, 4 had bladder cancer, and 5 had neuroblastoma. By age 20, the cumulative incidence of cancer was approximately 4% for NS and 15% for CS; both syndromes had a cancer incidence peak in childhood. The cancers described in CFCS and NSML overlapped with those reported in NS and CS. Future epidemiologic studies will be required to confirm the described cancer spectrum and to estimate precise cancer risks. Published 2011 Wiley‐Liss, Inc.
Stability of genetic regulatory networks with interval time‐varying delays and stochastic perturbation
Authors: He Yong , Fu Ling‐Yun , Zeng Jin , Wu Min
Published: April 2011

This paper studies the delay‐dependent stability for genetic regulatory networks with both interval time‐varying delays and stochastic perturbation. By considering the relationship among the time‐varying delays, its upper bound and their difference, and introducing an improved‐free‐weighting matrix (IFWM) approach, some less conservative stability criteria are proposed without ignoring any useful terms in the weak infinitesimal operator of the Lyapunov‐Krasovskii functional. Two numerical examples are given to illustrate the effectiveness and the reduced conservativeness of the obtained results.

© 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Fifty hertz magnetic fields individually affect chromatin conformation in human lymphocytes: Dependence on amplitude, temperature, and initial chromatin state
Authors: Sarimov Ruslan , Alipov Eugene D. , Belyaev Igor Y.
Published: April 2011

Effects of magnetic field (MF) at 50 Hz on chromatin conformation were studied by the method of anomalous viscosity time dependence (AVTD) in human lymphocytes from two healthy donors. MF within the peak amplitude range of 5–20 µT affected chromatin conformation. These MF effects differed significantly between studied donors, and depended on magnetic flux density and initial condensation of chromatin. While the initial state of chromatin was rather stable in one donor during one calendar year of measurements, the initial condensation varied significantly in cells from another donor. Both this variation and the MF effect depended on temperature during exposure. Despite these variations, the general rule was that MF condensed the relaxed chromatin and relaxed the condensed chromatin. Thus, in this study we show that individual effects of 50 Hz MF exposure at peak amplitudes within the range of 5–20 µT may be observed in human lymphocytes in dependence on the initial state of chromatin and temperature. Bioelectromagnetics 32:570–579, 2011. © 2011 Wiley‐Liss, Inc.
Cleavage of Phosphodiesters and of DNA by a Bis(guanidinium)naphthol Acting as a Metal‐Free Anion Receptor
Authors: Ullrich Stefan , Nazir Zarghun , Büsing Arne , Scheffer Ute , Wirth Daniela , Bats Jan W. , Dürner Gerd , Göbel Michael W.
Published: April 2011

Phosphoric acid diesters form anions at neutral pH. As a result of charge repulsion they are notoriously resistant to hydrolysis. Nucleophilic attack, however, can be promoted by different types of electrophilic catalysts that bind to the anions and reduce their negative charge density. Although in most cases phosphodiester‐cleaving enzymes and synthetic catalysts rely on Lewis acidic metal ions, some exploit the guanidinium residues of arginine as metal‐free electrophiles. Here we report that a combination of two guanidines and a hydroxy group yields highly reactive receptor molecules that can attack a broad range of phosphodiester substrates by nucleophilic displacement at phosphorus in a single‐turnover mode. Some stable O‐phosphates were isolated and characterized further by NMR spectroscopy. The bis(guanidinium)naphthols also cleave plasmid DNA, presumably by a transphosphorylation mechanism.
Model choice and squared prediction errors in PLS regression
Authors: Ergon Rolf , Halstensen Maths , Esbensen Kim H.
Published: April 2011

Squared prediction errors (SPE) in are discussed in relation to the conventional PLSR versus bidiagonalization model and algorithm issue concerning residual and prediction consistency, with focus on process monitoring and fault detection. Our analysis leads to the conclusion that conventional PLSR based on the NIPALS algorithm is ambiguous in SPE values caused by process faults. The basic reason for this is that the sample residuals are not found as projections onto the orthogonal complement of the space where the scores and regression solution are located, and where also the statistical limit is defined. The alternative non‐orthogonalized PLSR and bidiagonalization (Bidiag2) algorithms, as well as a simple re‐formulation of the NIPALS algorithm (RE‐PLSR), give unambiguous SPE values, and the last two of these also retain orthogonal score vectors. While prediction results from all of these methods in theory are identical, our conclusion is that methods where the and SPE values for process faults are uncorrelated should be preferred. Tests with added errors on real data do not indicate that this conclusion should be altered because of such errors. Copyright © 2011 John Wiley & Sons, Ltd.
High‐Temperature Experimental and Theoretical Study of Magnetic Interactions in Diamond and Pseudo‐Diamond Frameworks Built up from Hexanuclear Tantalum Clusters
Authors: Perić Berislav , Cordier Stéphane , Cuny Jérôme , Gautier Régis , Guizouarn Thierry , Planinić Pavica
Published: April 2011

Magnetic interactions in solid‐state tantalum cluster compounds have been evidenced by using magnetic susceptibility measurements and corroborated by broken‐symmetry DFT calculations. The three selected compounds are based on [Ta6X12(H2O)6]3+ (X=Cl or/and Br) units with edge‐bridged Ta6 octahedral clusters. Although two of them crystallise in the tetragonal space group I41/a, all compounds exhibit a similar arrangement of paramagnetic clusters related to the diamond structural framework (Fdm space group). Magnetic parameters were fitted by using the [5,4] Padé approximant of high‐temperature series expansion of susceptibility for the Heisenberg model (S=1/2) in the diamond framework, assuming only nearest‐neighbouring interactions. Such a model appropriately describes magnetic‐susceptibility measurements at temperatures T>0.7|J|/k. The magnetic interaction parameter J between two [Ta6Cl12(H2O)6]3+ clusters is estimated to be −64.28(7) cm−1; it has been enhanced by replacing several chlorine inner ligands with bromine ones (J=−123(3) cm−1 for two [Ta6Br7.7(1)Cl4.3(1) (H2O)6]3+ clusters) and is strongest between two bromine [Ta6Br12(H2O)6]3+ clusters with a value of −155(1) cm−1. Broken‐symmetry DFT calculations within spin–dimer analysis confirmed this trend. Those interactions can be explained on the basis of the overlap between singly occupied a2u orbitals localised on neighbouring clusters.
Enantioselective Conjugate Addition of Nitro Compounds to α,β‐Unsaturated Ketones: An Experimental and Computational Study
Authors: Manzano Rubén , Andrés José M. , Álvarez Rosana , Muruzábal María D. , de Lera Ángel R. , Pedrosa Rafael
Published: April 2011

A series of chiral thioureas derived from easily available diamines, prepared from α‐amino acids, have been tested as catalysts in the enantioselective Michael additions of nitroalkanes to α,β‐unsaturated ketones. The best results are obtained with the bifunctional catalyst prepared from L‐valine. This thiourea promotes the reaction with high enantioselectivities and chemical yields for aryl/vinyl ketones, but the enantiomeric ratio for alkyl/vinyl derivatives is very modest. The addition of substituted nitromethanes led to the corresponding adducts with excellent enantioselectivity but very poor diastereoselectivity. Evidence for the isomerization of the addition products has been obtained from the reaction of chalcone with [D3]nitromethane, which shows that the final addition products epimerize under the reaction conditions. The epimerization explains the low diastereoselectivity observed in the formation of adducts with two adjacent tertiary stereocenters. Density functional studies of the transition structures corresponding to two alternative activation modes of the nitroalkanes and α,β‐unsaturated ketones by the bifunctional organocatalyst have been carried out at the B3LYP/3‐21G* level. The computations are consistent with a reaction model involving the Michael addition of the thiourea‐activated nitronate to the ketone activated by the protonated amine of the organocatalyst. The enantioselectivities predicted by the computations are consistent with the experimental values obtained for aryl‐ and alkyl‐substituted α,β‐unsaturated ketones.
Exploration on asymmetric synthesis of flavanone catalyzed by (S)‐pyrrolidinyl tetrazole
Authors: Zhou Shubao , Zhou Yuqiang , Xing Yalan , Wang Naixing , Cao Linghua
Published: April 2011

An improved method of the synthesis of flavanones catalyzed by pyrrolidine and BF3·Et2O has been developed and a lot of flavanones could be easily synthesized via this method. The asymmetric synthesis of flavanone from benzaldehyde and 5‐fluoro‐2‐hydroxyacetophenone has been studied and flavanone with moderate enantioselectivity was obtained in one step. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Practical access to the proline analogs (S,S,S)‐ and (R,R,R)‐2‐methyloctahydroindole‐2‐carboxylic acids by HPLC enantioseparation
Authors: Sayago Francisco J. , Pueyo María J. , Calaza M. Isabel , Jiménez Ana I. , Cativiela Carlos
Published: April 2011

An efficient methodology for the preparation of the α‐tetrasubstituted proline analog (S,S,S)‐2‐methyloctahydroindole‐2‐carboxylic acid, (S,S,S)‐(αMe)Oic, and its enantiomer, (R,R,R)‐(αMe)Oic, has been developed. Starting from easily available substrates and through simple transformations, a racemic precursor has been synthesized in excellent yield and further subjected to HPLC resolution using a cellulose‐derived chiral stationary phase. Specifically, a semipreparative (250 mm × 20 mm ID) Chiralpak® IC column has allowed the efficient resolution of more than 4 g of racemate using a mixture of n‐hexane/tert‐butyl methyl ether/2‐propanol as the eluent. Multigram quantities of the target amino acids have been isolated in enantiomerically pure form and suitably protected for incorporation into peptides. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Chirality responsive helical poly(phenylacetylene) bearing L‐proline pendants
Authors: Kawamura Hiroaki , Takeyama Yoshihisa , Yamamoto Miho , Kurihara Hiroyuki , Morino Kazuhide , Yashima Eiji
Published: April 2011

A novel, optically active, cis‐transoidal poly(phenylacetylene) bearing an L‐proline residue as the pendant group (poly‐1) was prepared by the polymerization of the corresponding monomer using a rhodium catalyst in water, and its chiroptical property was investigated using circular dichroism spectroscopy. poly‐1 showed intense Cotton effects in the UV–visible region of the polymer backbone in water, resulting from the prevailing one‐handed helical conformation induced by the covalent‐bonded chiral L‐proline pendants and exhibited a unique helix‐sense inversion in response to external, achiral, and chiral stimuli, such as the solvent and interactions with chiral small molecules. We found that poly‐1 could enantioselectively trap 1,1′‐2‐binaphthol within its hydrophobic helical cavity inside the polymer in aqueous media and underwent an inversion of its helical sense in the presence of one of the enantiomers. The effect of the optical purity of 1,1′‐2‐binaphthol on the chiroptical properties of poly‐1 was also investigated. Chirality 23:35–42, 2011 © 2011 Wiley Periodicals, Inc.
A DV‐Xα study on the electronic structures of cubane‐like iron‐sulfur cluster compounds
Authors: Tang Huang , Liu Chun‐Wan
Published: April 2011

The electronic structures of six cubane‐like cluster compounds of the type [Fe4S4L4]n (L = SH, OH, and Cl, n=‐2 and −3; L=NO, n = 0 and −1) have been calculated by using DV‐Xα method, and the bonding properties are discussed with emphasis on the ligand effect on cluster bonding. The comparisons of MO energies and cluster charge distributions with the experimental data are made, and the differences between the early studies and the present one are also briefly commented.
Quantum‐chemical investigation on hydrogen bonding interaction of hydrogen fluoride dimer at various mutual orientations
Authors: Ji‐Min (J. M. Yan) Yan , Williams D. E.
Published: April 2011

Hydrogen bonding interaction in hydrogen fluoride dimer has been investigated by quantum‐chemical calculation with 6‐311G** basis set at various mutual orientations. Atomic charges and charge transfer have been calculated by means of potential‐derived method, and decomposition of hydrogen bonding interaction has been executed. The calculation results show that there is a variation range for the energy‐stable orientations, the charge transfer in the range presents maximum value, and the charge transfer interaction plays a decisive role in the hydrogen bonding.
The ion transfer of the basic dye rhodamine B across the liquid‐liquid interface of two immiscible solvents
Authors: Sun Zhi‐Sheng , Wang Er‐Kang
Published: April 2011

The ion transfer of the basic dye rhodamine B at the interface between water and nitrobenzene, water and 1, 2‐dichloroethane, as well as water and nitrobenzene ‐ chlorobenzene mixtures has been studied by cyclic voltammetry and chronopotentiometry with linear current scanning. A transfer mechanism of rhodamine B is proposed in terms of its electrochemical behavior, dissociation and distribution equilibria, and is ascribed as diffusion‐controlled reversible process of rhodamine B. The experimental data obtained for the relationship between interracial half‐wave potential ΔWoφ° and pH are in agreement with the theoretical equation based on the mechanism, and the standard interfacial potential differences ΔWoφ° and standard Gibbs energies ΔWoG° are calculated by extrapolation. The effect of the nature of solvent on the transfer behavior and the stability of the interface have been discussed.
The synthesis and structural studies of mixed ligand complex, tris(1‐phenyl‐3‐methyl‐4‐trifluoroacetyl‐pyrazol‐5‐one)mono(1‐phenyl‐3‐methyl‐pyrazol‐5‐one)neodymium(III) monohydrate
Authors: Huang Chun‐Hui , Zhang Shi‐Wei , Deng An‐Ping , Tang Hui‐Tong , Xu Guang‐Xian
Published: April 2011

A mixed ligand neodymium complex containing 1‐phenyl‐3‐methyl‐4‐trifluoroacetyl‐pyrazol‐5‐one (HPMTFP) and 1‐phenyl‐3‐methyl‐pyrazol‐5‐one (PMP), with molecular formula Nd (PMTFP)3·PMP·H2O was synthesized. Its crystal and molecular structure has been determined by single crystal X‐ray diffraction method. The complex crystallizes in monoclinic system with space group C52‐P21/n. There are four formula units in a cell of dimensions a = 12.837(3), b = 23.763(5), c = 16.810(4) Å, β = 109.58(2)°. The structure has been refined by full‐matrix least‐squares techniques to a final R value of 0.0487 and Rw value of 0.432. The neodymium atom is coordinated to eight oxygen atoms with the average Nd—O bond length 2.439Å. Its thermostability, and mass spectrum have been discussed.
Crystal and molecular structure of guanidinium hexatungsto‐bis(p‐aminophenylarsonate) tetrahydrate,[C(NH2)3]4[p‐NH3C6H4As)2W6O25]·4H2O
Authors: Liu Ben‐Yao , Ku (Gu Yi‐Dong) Yih‐Tong , Gu Yi‐Dong , Wang Xin
Published: April 2011

The crystal structure of a new type arylarsonic polytungstate [C(NH2)3]4[p‐NH3C6H4As)2W6O25]·4H2O was determined by single‐crystal X‐ray diffraction analysis. It belongs to triclinic, space group \documentclass{article}\pagestyle{empty}\begin{document} \[ P\bar 1 \] \end{document}, with cell dimensions a = 12.863(3), b = 18.912(3), c = 21.383(4) Å α = 91.14(2)°, β = 93.65(3)°, γ = 92.25(3)°, V = 5185.9 Å3, Z = 4, Dc = 2.753 g/cm3. The intensity data were collected on an Enraf‐Nonius CAD4 diffractometer with Mo Kα radiation. The positions of all tungsten and arsenic atoms were determined by direct method. The other non‐hydrogen atoms were revealed by difference Fourier synthesis. The structure was refined by fullmatrix least‐squares procedure to a final R value of 0.070. The crystal structure contains two similar but nonidentical molecules. Two similar anions consist of a ring of six WO6 octahedra, which are connected with one face‐sharing, two corner‐sharings and three edge‐sharings, and two p‐aminophenylarsonic tetrahedra capped above and below the ring. In each WO6 ring, four tungsten atoms, which are joined with edge‐sharing oxygen atoms, are almost coplanar, while the two others, which are joined with face‐sharing oxygen atoms, protrude out of the ring towards the same side. The two arsenic atoms in each anion are not equivalent in their bonding manner. In each anion, all non‐hydrogen atoms of each organic group are in the same plane. Each molecule contains one anion, four C(NH2)3+ cations and four water molecules. There are many hydrogen bonds between cations and anions throughout the whole crystal. The amino groups can accept protons, so that the charge of the resulting anion decreases and [(RAs)2W6O25]4‐ type complexes are formed.
The improvement of Cα atom positions of trichosanthin—–An application of phase filtering procedure to three‐dimensional structure determination of protein
Authors: Xia Zong‐Xiang , Zhang Zhi‐Ming
Published: April 2011

Wang's phase filtering procedure has been applied to the structure study of trichosanthin crystals belonging to space group C2. The MIR phases at 3Å resolution have been improved with the accumulative phase shift of 31.8° and the figure of merit has been improved from 0.54 to 0.84. The resulted electron density map at 3Å resolution has been much improved with a higher ratio of the electron density of the protein to the noise in the solvent region. The minimap has been interpreted more reasonably than the previous maps, giving the overall course of the polypeptide chain substantially the same as previously reported except for containing more secondary structure and a few short segments traced differently. The first 85 Cα atoms of the polypeptide chain are located in about the same positions as determined previously with an exception of a short segment but the amino acid residues after that shift along the chain with a maximum shift of about 15 residues. The electron density of side chains agrees better with the primary structure. The conformation and the three‐dimensional structure as well as the major heavy‐atom binding sites for the two molecules in an asymmetric unit are substantially the same. The structure of trichosanthin shows more similarity to ricin A chain than that reported previously.
Photochemical properties of hypocrellin A, B and their oxides
Authors: Zhao Kai‐Hong , Jiang Li‐Jin
Published: April 2011

Hypocrellin A and B in methanol were autosensitized and photooxygenated to 1, 4, 6, 7 and 2, 5, 8, 9 respectively. 1 in methanol was photooxygenated to 6 and 7 under the sensitization by HB. 1 in methanol was photooxygenated to 7 under the sensitization by Rose bengal. 1 in benzene irradiated with medium‐pressure‐mercury lamp was photolyzed to 3 in the presence of iodine.
Intramolecular energy transfer between chromophores separated by a rigid steroid bridge: II. Energy transfer as a probe to determine the ratio of two epimers
Authors: Tong Zhen‐He , Yang Guo‐Qiang , Wu Shi‐Kang
Published: April 2011

The singlet‐singlet intramolecular energy transfer between naphthalene moiety and dansy! group held apart by a rigid steroid bridge was investigated for two molecules: β‐(1‐naphthyl) acetoxy‐17α‐dansyl‐Δ5androstene (3a) and 3β‐(1‐naphthyl)acetoxy‐17 β‐dansyl‐Δ5androstene (3b). The rates of energy transfer for 3a and 3b in cyclohexane are 6.9 × 106 and 1.1 × 108 s−1 respectively. The difference in energy transfer rate between 3a and 3b is attributed to the different donor‐acceptor separation and orientation. The ratio of the two epimers in the synthesized product mixture was obtained from the fluorescence decay measurements.
Studies on sulfinato‐dehalogenation: XII. Sodium dithionite‐initiated addition of N, N‐diethyliododifluoroacetamide to multiple bonds
Authors: Huang Wei‐Yuan , Lü Long , Zhang Yuan‐Fa
Published: April 2011

N, N‐deithyl‐iododifluoroacetamide 1 reacted with alkenes, alkynes in aqueous acetonitrile solutions of sodium dithionite and sodium hydrogen carbonate at room temperature to give the corresponding adducts, thus constituting a new method for introducing the CF2 group into organic molecules. Compound 1 reacted with conjugated olefins 2b, c to afford the iodine‐free adducts 7b, c. The adducts 3d—f, from addition of 1 to alkenes 2d—f, could be converted into α,α‐difluoro‐γ‐lactones 5d—f by treatment with silica gel. Compound 1 reacted with ethyl vinyl ether 2i to give aldehyde 8, and perfluoroalkyl or polyfluoroalkyl iodides reacted similarly. A radical mechanism was proposed for the addition reaction. Under the same condition, N,N‐diethyl‐bromodifluoroacetamide produced only the corresponding sulfinate Et2NC(O)CF2SO2Na.
Total synthesis of cis‐shisool
Authors: Wang Zhi‐Qin , Lai Chun‐Qiu
Published: April 2011

This paper describes the total synthesis of cis‐shisool through intermediate 3, which was derived from the Diels‐Alder adduct 4 (or 5). The structure of the isomers produced by the Diels‐Alder reaction of cyclohexadiene and crotonate has been elucidated by means of GC and NMR. Methylenation of 12 with Zn‐CH2Br2‐TiCl4 or Ph3P=CH2 retains the stereochemistry of the carbon atom adjacent to the carbonyl group.
Asymmetric epoxidation of gibberellates by the modified Sharpless reagent
Authors: Wang Zhi‐Min , Zhou Wei‐Shan
Published: April 2011

Asymmetric epoxidation of methyl gibberellate by the modified Sharpless reagent at various temperature is described. Compound 8 and 9 can be used as the key intermediates for the syntheses of the polyhydroxygibberellins.
Organic reactions in chiral micelles: 7. The structural effects on the asymmetric oxidation of prochiral sulfides in chiral micelles
Authors: Zhang Yong‐Min , Fu Chun‐Ling , Fan Wei‐Qiang
Published: April 2011

A variety of phenyl alkyl sulfides were oxidized enantioselectively with NaIO4 in chiral micellar systems formed from eight chiral surfactants, to give optical active sulfoxides. The enantiomer excesses ranged from 1.6 to 15.0%. To understand the mechanistic detail of this asymmetric oxidation in chiral micelle, the effects of structure both in substrates and surfactants on the optical yield of the oxidation were studied and discussed. Generally, increasing the alkyl chain length both in surfactants and in substrates enhances the optical yield, also the surfactant with hydroxy group at its appropriate position gives better enantioselectivity, suggesting the enzymic characteristics of the chiral micelle.
Structures and isomerizations of carbenoids H2CCCLiX (X  F, Cl)
Authors: Bing‐Ze Wang , Cong‐Hao Deng
Published: April 2011

Novel structures of H2CCCLiX (X  F, Cl) were determined using HF/STO‐3G gradient method. Both of the carbenoids have two equilibrium structures, askew and linear forms, at the level of calculation. In the case XF, the former is more stable, but in the case X=Cl, the latter is more stable. The frontier MOs are given and analyzed.
Mechanisms of ring contraction, C—H insertion and 1,2‐hydrogen migration of cyclobutylidene
Authors: Bing‐Ze Wang , Cong‐Hao Deng
Published: April 2011

Isomerizations of cyclobutylidene 1 to methylenecyclopropane 2, cyclobutene 3 and bicyclobutane 4 have been studied using ab initio method. Equilibrium and transition structures are fully optimized with 3–21G basis set. The reaction barriers are 78, 75 and 110 kJ/mol at 6–31 G**, respectively, 1→2 occurs via the outward disrotation of two end C‐C bonds, 1→3 via the attack of an exo hydrogen to the carbene p AO before the transition state, and 1→4 is unable to compete with 1→2 and 1→3 for its higher barrier.
Theoretical calculation of the singlet‐triplet electronic transition and photochemical reactivity in carbonyl fluoride, trifluoroacetyl fluoride and perfluoromethyl perfluoroacetate
Authors: Ottavianelli E. , Castro E. A. , Jubert A. H.
Published: April 2011

Molecular properties following electronic excitation were studied and calculations were performed for the singlet‐triplet electronic transitions of carbonyl fluoride, perfluoroacetyl fluoride and perfluoromethyl perfluoroacetate by means of the CNDO/S‐CI method. Various approximations were used to evaluate the core Hamiltonian matrix elements.
Further results on systematic regularities of molecular SCF energies
Authors: Castro E. A.
Published: April 2011

Two new approximate formulas to compute molecular electronic energy are tested with regard to a set of 55 molecules of nearly double‐zeta quality in order to complement previous work. Although qualitative results are in line with recent findings, the numerical data shows a potentially significant disagreement.
Studies on organo‐phosphorus, ‐arsonic, and ‐antimony polytungstates and polymolybdates: VI. A new guanidinium hexamolybdobisphenylarsonate monohydrate (CN3H6)5 [(C6H5As)2Mo6O25H]·H2O
Authors: Ben‐Yao Liu , Yih‐Tong (Gu, Yi‐Dong) Ku , Ming Wang , Pei‐Ju Zheng
Published: April 2011

A new guanidinium hexamolybdobisphenylarsonate which is quite different from that reported in literature has been synthesized and characterized. This new salt which is isostructural with its tungsten congener crystallized as monoclinic, space group P21/a with cell dimensions of a=15.005 (1), b = 17.559(1), c = 18.008(2) Å, β = 97.24(1)°. Its elemental analyses, IR and UV spectra have been reported and discussed. Its thermal properties and electrochemical behavior have also been reported.
Stability of ternary amino acid complexes and its computer simulation under physiological conditions
Authors: Zhong‐Xian Huang , Xiao‐Yin Dai , Xiao Hua , Xu Chang
Published: April 2011

The binary and ternary formation constants of mixed amino acid complexes with Zn(II), Cu(II), Ni(II) and Cd(II) have been potentiometrically determined under physiological conditions. The symbiosis of HSAB does play a role in the formation of ternary amino acid complexes. Comparing with Zn(II), as a softer Lewis acid Ni(II) shows its preference to softer Lewis bases cysteinate and histidinate. These soft Lewis bases more likely gather together in the mixed amino acid complexes. It is expected that the ternary amino acid complexes are overwhelming in the distribution of complex species especially at biological conditions. In the case of zinc, differring from previous study the alaninate‐containing mixed complexes become the predominant species formed in the region of pH 7.4.
The formation and properties of glass in the ZrF4‐BaF2‐ThF4 system
Authors: Ke‐Li Zhang , You‐Lan Xia , Zhen‐Duo Li , Qi‐Hua Yuan
Published: April 2011

The formation and properties of fluoride glasses in the ZrF4‐BaF2‐ThF4 system were examined. The limits of the glassforming region were defined. A series of new quaternary glasses ZrF4‐BaF2‐ThF4‐MFx (x = 1, 2, 3, and M = Li, Na, Ca, Sr, Zn, Cd, Pb, Al, Y, La, Gd) were obtained. The ultraviolet‐visible and infrared transmission spectra, characteristic temperatures, refractive indices and densities for the fluoride glasses were determined. Glass in the quaternary systems was more stable than that in ternary system. These glasses were promising materials for infrared transmission, because of their good optical qualities and stability against devitrification.
Preparation and photochromism of piperidine decatungstate
Authors: Song Yuan , Huang Qin , Yih‐Tong (Gu, Yi‐Dong) Ku
Published: April 2011

A new photochromic compound, piperidine decatungstate (PiPdDT), (C5H10NH2)4W10O32 was prepared; its TG curve, UV and IR spectra were studied. On exposure to UV light, both its crystal and aqueous solution turn blue with absorption spectra appearing at 756 and 720–742 nm. The ESR signal, recorded at 100 K on a frozen solution of PiPdDT in water after exposure to UV light, centered around g = 1.839. The fading rate constant after exposure to UV light, is k = 7.9 × 10−4s−1, and its quantum yield was determined as ϕw(v) = 22.2, which is higher than the values yet reported for polytungstates in literature.
Synthesis, crystal structure of Z‐1,2‐dimethyl‐1,2‐bis‐(m‐ferrocenyl‐phenyl)ethene
Authors: Xiu‐Ren Bu , Xiao‐Zeng You , Qing‐Jin Meng , Man‐Fang Wang
Published: April 2011

The binuclear ferrocene derivative, Z‐1, 2‐dimethyl‐1, 2‐bis (m‐ferrocenylphenyl)e hene (Z‐DDFP) has been isolated from the mixture of the coupling reaction of m‐ferrocenylacetophenone (m‐FAP) by the low‐valent titanium salts obtained from zinc/titanium tetrachloride in THF. The single crystal X‐ray structure of the complex as benzene solvate has been determined and found to be triclinic with cell constants a=7.748(5), b=10.600(7), c=18.550(4)Å, α=97.565(5)°, β=98.551(8)°, γ=90.318(8)° and V=1494.2Å3. The structure was refined by [least‐squares method for 5151 independent reflections with I>3σ(I) to a final R=0.0363 and Rw=0.0523. The two cyclopentadienyl rings in each ferrocenyl unit are approximately parallel. The two phenyl rings are significantly twisted by 66.80° from each other in the stable configuration. Both the ferrocenyl units on the same side of the C=C double bond are not co‐planar with a mean dihedral angle of 96.28°. The structural analysis shows that the chain linking two central iron atoms is about 18Å, significantly close to those found in some biological models.
The chemical characterization of the cephalic secretion of the Australian colletid bee, Hylaeus albonitens (Gnathoprosop's Cockerell)
Authors: Zheng‐Ming Li , Batra S. W. T. , Plimmer J. R.
Published: April 2011

The cephalic extract of Australian colletid bee, Hylaeus albonitens, comprises 10 components: linalool, citronellal, neral, geranial, nerolic acid, geranic acid, heptadecane, pentacosane, Z,Z‐ and E,E‐9,12‐octadecadienoic acid. Quantification of these major components suggested it to be an aggregation pheromone composition. The fairly large amounts of 9,12‐octadecadienoic acids have not been reported before in the cephalic extract of bees. The chromatographic pattern is quite different from the previous reports on the constituents of mandibular glands of American Hylaeus modestus and the related European and North American Colletes bees.
Product distribution of the reaction of unsymmetrical β‐diketones with hydroxylamine hydrochloride
Authors: Ben‐Li Zhang , Jin‐Cong Zhuo , Zhen‐Heng Gao
Published: April 2011

Two series of unsymmetrical β‐diketones (1‐aryl‐3‐tolylpropane‐1, 3‐diones and 1‐alkylbutane‐1, 3‐diones) were synthesized and treated with hydroxylamine hydrochloride. The product distributions of the reactions were studied based on 1H NMR data. The systematical influence of the substituents on the structures of the products is discussed.
Studies on sulfinato‐dehalogenation: XI. Sodium dithionite‐initiated perfluoroalkylation of electron‐rich aromatic
Authors: Wei‐Yuan Huang , Wu‐Ping Ma , Wei Wang
Published: April 2011

The intermediary perfluoroalkyl radical generated from the reaction of perfluoroalkyl iodide with sodium dithionite was shown to be reactive toward phenols and aromatic amines, and resulted in the formation of a mixture of ortho‐ and para‐substituted products. Thus, the reaction provides a new method for the synthesis of ortho‐ and para‐perfluoroalkyl substituted phenols and anilines.
Sensitized photooxygenation: IV. Synthesis and singlet oxygenation of ethyl 6‐ethyl‐3, 4‐dihydro‐2H‐pyran‐5‐carboxylate and ethyl 6‐isopropyl‐3, 4‐dihydro‐2H‐pyran‐5‐carboxylate
Authors: Ze‐En Huang , Xiao‐Guang (Hiu‐Kwong Leung) Liang , Leung Hiu‐Kwong , Yuk‐Yee Chan
Published: April 2011

Title compound 2b and 2c were synthesized via the condensation of 1, 3‐dibromopropane with the appropriate β‐keto ester under mildly basic condition. Photooxygenation of them under singlet oxygenation condition gives two kinds of product, namely, dioxetane‐product and ene‐product, with polar solvents, favoring the formation of the former. Comparison of the present study with that of the 6‐methyl substrate 2a indicates that the effect of steric hindrance at the 6‐position is significant, but not in a simple linear relationship to the reaction.
Theoretical study on the isomerization reaction of fluorine substituted disilene
Authors: Ju Guan‐Zhi , Ma Wan‐Yong , Christoffel Kurt
Published: April 2011

For the isomerization reaction of monofluoro‐disilene, the geometrical structures of reactant, product and transition state have been optimized and energy constant, vibrational frequency calculated. By means of the statistical thermodynamics and Eyring's transition state theory, the equilibrium constant, rate constant and heat of isomerization have also been computed. Hence, this reaction has been analysed completely.
INDO/GIAO calculations of 13C, 15N and 17O NMR chemical shifts in some organo‐iron complexes
Authors: Wu Wei‐Xiong , Cao Yang , You Xiao‐Zeng , Dai An‐Bang
Published: April 2011

In this paper, INDO perturbation theory has been extended to calculate the NMR chemical shifts of transition metal compounds. The nitrogen and oxygen INDO parameters have been refined by using a set of nitrogen and oxygen containing compounds to minimize the differences between calculated and experimental 13C, 15N, and 17O shielding constants. These refined parameters, together with optimally selected iron INDO parameters, were used to evaluate the 13C chemical shifts of three iron complexes (C5H5)Fe(CO)2CN, (C5H4CHO)2Fe2, and (C5H4CH2OH)2Fe. The calculated 13C, 15N and 17O shielding constants were fairly in agreement with experimental results. In addition, a good linear relationship between the calculated [diamagnetic shielding constants σd(M) of 13C, 15N and 17O nuclei and the net charge ρ (M) of these atoms was noticed.
Catalyt properties of tungsten oxycarbide and carbide in hydrocarbon conversion
Authors: Gao Zi , Qin Dai‐Yi
Published: April 2011

Tungsten oxycarbide with specific surface area ⋍ 24 m2/g was prepared from white tungstic acid by reduction and carburization with CO and H2. XRD and EXAFS measurements confirmed that the WOC obtained has a simple hexagonal structure isotypic with α‐WC and the oxygen is inserted into the trigonal prismatic interstices of the crystal lattice. The reactions of n‐hexane, n‐heptane and cyclohexane on WOC were studied and compared with WC prepared by direct synthesis at high temperature. WOC and WC are active for the hydrogenolysis, isomerization and dehydrocyclization of alkanes and dehydrogenation of cyclohexane and their catalytic properties are in many ways similar to Pt catalysts. Oxygen insertion inhibits the catalytic activities of tungsten carbide for hydrocarbon conversion reactions probably due to electronic effect.