bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ab initio study on mechanisms of singlet oxygen reaction with ethylene
Authors: Chen De‐Zhan , Chen Bao‐Ji , Ning Shi‐Guang 
Published: September 2010

AbstractThe reaction of singlet oxygen with ethylene has been studied at the ab initio level with both HF/3–21G and HF/6–31G* basis sets, fully optimizing the geometries of the critical points. The transition state leading to the intermediate peroxirane from the initial reactants is found, located at 81.71 kJ/mol above the dissociation limit The vibrational analysis is done with two basis sets. From the results it can be seen that the frequencies have not been made an improvement obviously with augmented 6–31G* compared to 3–21G basis; it follows that main reason for too high HF/3–21G frequency could mainly be the vibrational anharmonicity. The eigenvector corresponding to the single imaginary vibrational frequency is dominated by the larger O—O distance. The finding of the transition state confirms that the peroxirane minimum can be reachable passing through a peroxirane‐like saddle point. In addition, the mechanisms of the reaction forming oxirane are discussed as well.
Preparation and spectroscopic properties of 2′,5′‐dideoxynucleosidylcobalamins
Authors: Yan Hong , Chen Hui‐Lan , Sun Hong‐Zhe , Xie De‐Ping , Tang Wen‐Xia 
Published: September 2010

AbstractTwo new coenzyme B12 analogues, 2′,5′‐dideoxycytidylcobalamin (2a) and 2′,5′‐dideoxyuridinylcobalamin (2b), and two others, 2′,5′‐dideoxyadenosylcobalamin (2c), and 5′‐deoxythymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV‐vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.
Synthesis of adamantane on zeolite catalysts
Authors: Gao Zi , Yang Xiao‐Bo 
Published: September 2010

AbstractThe synthesis of adamantane from tetrahydrodicyclopentadiene on zeolites with different framework structures was studied. The adamantane yield on HY zeolites is higher than on HM and HZSM‐5 zeolites. Among various types of dealuminated HY zeolites the HEY and HUSY zeolites give higher adamantane yields than conventional HY zeolite. The changes in activity and selectivity of the main and side reactions are correlated with the acidity and the pore structure of the zeolites. To ion‐exchange the HY and HUSY zeolites with Ni2+ and La3+ cations may further improve the activity and selectivity of the zeolite catalysts.
A study of vitamin A radical cation generated by chemical and radiolytic oxidation
Authors: Guo Qing‐Xiang , Ren Tan , Li Bin , Wang Jun , Liu You‐Cheng , Tu Tie‐Cheng , Dong Ji‐Rong 
Published: September 2010

AbstractElectron transfer reaction between vitamin A (1) and tris(p‐bromophenyl)aminium bexachloroantimonate (2) in dichloromethane (DCM) has been investigated by means of UV‐VIS absorption and ESR spectroscopy. The title radical cation formed in the reaction was characterized by a new absorption band around 600 nm and a singlet unresolved ESR spectrum with g factor of 2.0038–2.0039 and line width of 20 G. Further studies indicated that ESR pattern and parameters of the radical cation generated by γ‐irradiation of 1 in CFCl3 matrix at 77 K are consistent with that resulted in the chemical oxidation in DCM at ambient temperature.
A study on the reaction of 2′‐hydroxychalcones with I2‐H2SO4‐DMSO system
Authors: Zhang Fang‐Jie , Li Yu‐Lin 
Published: September 2010

AbstractThe reaction of 2′‐hydroxychalcones with I2‐H2SO4‐DMSO system has been studied. The results obtained by us are entirely different from those reported in the literature. The mechanism of this reaction has also been investigated.
Study on the alkylation reaction of guanine and N‐acetylguanine and the synthesis of 1′‐C alkylated carba‐DHPG analogues
Authors: Liu Yu‐Gang , Fei Chang‐Pei , Chan Tak‐Hang 
Published: September 2010

AbstractThe alkylation reaction of guanine and N‐acetylguanine with model compounds such as isopropyl bromide or 4‐heptyl tosylate were studied. The reaction conditions such as temperature, solvent, base, and catalyst were examined for their effects on the reaction rate, and the yield and regioselectivity of the coupling reaction. The highest yield was obtained by using DMSO as the solvent. The reaction proceeded in a homogenous manner to give higher yield of 9‐N and 7‐N substituted product in a mole ratio of 1:1. The ratio could be raised to 2:1 if dibenzo‐18‐crown‐6 was used as a catalyst. Using the above procedure, three carba‐DHPG analogues bearing different 1′‐C alkyl side chains were synthesized.
Electrochemical behavior of C60 modified electrode in aqueous solutions
Authors: Shi Zhan‐Ling , Mao Yi‐Ping , Tong Wei , Jin Li‐Tong 
Published: September 2010

AbstractThe construction of adsorptive type Ceo modified electrode and its electrochemical reduction and oxidation behavior in aqueous solutions are described in this report. Four pairs of one‐electron transfer reduction and oxidation cyclic voltammetry is obtained in aqueous solution containing 30% CH3CN and 2% (C3H5)4NOH. It is reported in this paper that the Ceo modified electrode also catalyzes the electrochemical reduction of dissolved oxygen in 40% DMF and 2% (C2H5)4NOH aqueous solution and this might open a new field for the potential applications of C60 in electrochemistry and electroanalytical chemistry.
Study on polymerization and structure of polydiphenylamine
Authors: Jin Wen , Song Fa‐Yi , Dong Shao‐Jun 
Published: September 2010

AbstractThe electrochemical oxidation of diphenylamine in acetonitrile produces an adherent uniform polymer film which exhibits mutiple colour variation(yellow‐green‐blue) in a wide range of potential scan. The polymerization mechanism and the structure of the polymer were studied by cyclic voltammetry, FT‐IR and in situ ESR. The results indicate that the electrochemical polymerization of diphenylamine belongs to a cationic radical polymerization process. During electrolysis, only oligomers were initialy produced, then polymer film was formed on the electrode surface. The electropolymerization performs via the 4,4′ C‐C phenyl‐phenyl coupling mechanism.
The synthesis and phase transition of 4′‐methylphenyl 4″‐[(4‐alkoxy‐2,3,5,6‐tetrafluorophenyl)ethynyl]benzoates
Authors: Xu Yu‐Lian , Wang Wei‐Li , Chen Qi , Wen Jian‐Xun 
Published: September 2010

AbstractA homologous aeries of 4′‐methylphenyl 4″‐[(4‐alkoxy‐2,3,5,6‐tetrafluorophenyl)ethynyl]‐benzoates have been synthesized. Polarizing microscopic textural observation shows that such compounds exhibit enantiotropic nematic phase.
Synthesis of 1,4,6‐tri‐O‐benzyl myo‐inositol—A key intermediate to myo‐inositol‐1,2,5‐O‐trisphosphate
Authors: Yuan Cheng‐Ye , Zhai Hai‐Xiao , Weng Guan‐Hong 
Published: September 2010

AbstractA new synthetic approach to 1,4,6‐tri‐O‐benzyl myo‐inositol was described on the basis of the regioselective benzylation of 1,2‐O‐iaopropylidene‐4,6‐di‐O‐benzyl myo‐inositol, subsequent acid hydrolysis, phosphorylation with tetrabenazylpyrophosphate and appropriate deprotection.
Temperature effect on the ease of aggregation
Authors: Zhang Jin‐Tao , Nie Jin , Sun Si‐Xun , Ji Guo‐Zhen , Jiang Xi‐Kui 
Published: September 2010

AbstractThe effect of temperature on the critical aggregate concentration (CAgC) has been investigated for the first time, by measurement of the hydrolytic rate constants of p‐nitrophenyl dodecanoate (C12) and hexadecanoate (C16) at different temperatures in the 30:70 V/V (θ·=0.30) and 40:60 V/V (θ = 0.40) dioxane (DX)‐H2O systems. The CAgC values of C12 and C16 increase with the increase of the temperature, i.e., high temperatures disfavor aggregation. Activation energies for the hydrolysis of C12 in the monomeric and aggregated concentration domains have also been discussed.
The further crystallographic refinement of trichosanthin at 2.7 A resolution and the comparison among the three molecular structures in two crystal forms
Authors: Zhang Lei , Xia Zong‐Xiang , Wu Shen , Dong Yi‐Cheng 
Published: September 2010

AbstractThe three‐dimensional structure of trichosanthin at 2.7Å resolution has been improved further, by refitting one of the C‐terminal tails, adjusting 16 residues in the molecular surface regions, discarding some water molecules with high B values, and adjusting weights during the further refinement. The R‐factor has been reduced to 18.5% and the r.m.s deviations from ideal geometry are also improved. The structures of the two molecules in the monoclinic asymmetric unit and the only molecule in the orthorhombic asymmetric unit are compared with one another. The main‐chain structures for most of the residues in the three molecules are substantially the same. However, the courses of the three C‐terminal tails are completely different, and the intermolecular interactions resulting from the particular packing of the molecules in the crystals account for the differences. The strand βe‐2 and the preceding β‐turn in small domain show large r.m.s. deviations among the three molecules and they are also involved in intermolecular interactions.
Synthesis and magnetic properties of binuclear cobalt(II), nickel(II) and copper (II) complexes bridged by oxamidate group
Authors: Jiang Zong‐Hui , Deng Chao‐Li , Liao Dai‐Zheng , Yan Shi‐Ping , Wang Geng‐Lin 
Published: September 2010

AbstractFour binuclear Co(II), Ni(II) and Cu(II) complexes bridged by oxamidate (oxd) group have been synthesized, namely Co2(byp)2(oxd)(C104)2 (1), Co2(Me2bpy)2(oxd)(ClO4)2·H2O (2), Ni2(bpy)2(oxd)(ClO4)2·2H2O (3) and Cu2(Me2bpy)2(oxd)(NO3)2 (4). (bpy=2,2′‐bipyridyl, Me2‐bpy=4,4′‐dimethylbipyridyl, oxd=oxamidate) The complexes are characterized by IR, UV spectra, EPR and variable‐temperature magnetic susceptibility (4–300 K). The susceptibility data for complexes 1 and 3 were least‐squares fit to the susceptibility equation derived from the spin Hamiltonian Ȟ=‐2J · Š1·2. The exchange integral, J, was found to be equal to −3.62 cm−1 in 1 and −1.82 cm−1 in 3. This indicates a weak antiferromagnetic spin exchange interaction between the metal ions.
Synthesis, spectroscopic properties, and tautomerism of mono‐meso‐substituted octamethylporphyrins
Authors: Li Ming , Yao Yi‐Ming , Zou Jian‐Zhong , Xu Zheng , You Xiao‐Zeng 
Published: September 2010

AbstractThe synthesis spectroscopic properties and tautomerism of four novel mono‐mesosubstituted(R)‐octamethylporphyrins (R=o‐hydroxybenzyl, p‐aminobenzyl, 4‐pyridinyl, and ferrocenyl) were investigated. It was found that the porphyrins2, 3 could be directly prepared in good yields via the coupling reaction of salicylaldehyde and p‐aminobenzyl aldehyde with octamethyl‐1′,8′‐dideoxy‐ac‐biladiene dihydrobromide, respectively. The free energy of activation (ΔG≠) of the tautomerism of the porphyrins was calculated and interpreted in terms of electronic and steric nature. In contrast with 2‐substituted‐5,10,15,20‐tetraphenylporphyrins, the substituents in meso position do not change the relative amount of two tautomers a and b.
Syntheses, properties and structures of copper and nickel complexes of 6,7‐dihydro‐5H‐1,4‐dithiepin‐2,3‐dithiolate
Authors: Yao Tian‐Ming , You Xiao‐Zeng , Yang Qing‐Chuan 
Published: September 2010

AbstractThe reaction of CuCl2·2H2O or NiCl2·6H2O with K2(C5H6S4) [potassium salt of 6,7‐dihydro‐5H‐1,4‐dithiepin‐2,3‐dithiolate] under nitrogen atmosphere resulted in the isolation of [Cu(C5H6S4)2]− or [Ni(C5H6S4)2]− as the tetrabutylammonium salt. Both complexes show characteristic IR and UV −Vis absorptions of transition metal dithiolenes. Cyclic voltammograms contain two waves indicating a two step electrochemical procedure [M(C5H6S4)2]0 = [M(C5H6S4)2]1‐= [M(C5H6S4)2]2‐ Single crystal structure study has been carried out on the nickel complex. Crystal of [Bu4N][Ni(C5H6S4)2] belongs to monoclinic space group P21/c with a=17.576(5), b=10.883(2), c=17.773(4) A, β=91.07(2)°, Z=4, and ρ(calcd.)=1.348 g/cm3. Final result is R=0.059 for 2959 reflections. The NiS4 core exhibits square planar coordination with average Ni—S bond length of 2.134(5) Å. There are not anion pairs in crystal. The anions stack along a and c axes while the cations intercalate in them. The nearest S—S contact is 4.429 Å. The solid powder ESR spectrum of the nickel complex shows three broadening signals at g1 =2.097, g2=2.042, g3=2.022. Magnetic susceptibility data for [Bu4N][Ni(C5H6S4)2] reveal enhanced anti‐ferromagnetic interaction.
An open chain product in the reaction of benzil with thiocarbohydrazide
Authors: Deng Shui‐Quan , Huang Xiao‐Yin , Zhuang Hong‐Hui , Huang Jin‐Ling , Lin Zhen‐Guang 
Published: September 2010

AbstractAn open chain compound was obtained by reaction of benzil with thiocarbohydrazide in acidic condition. Its derivative, namely, benzil bis‐(5‐isopropylidene‐3‐thiocarbohydrazone) has been structurally characterized by X‐ray single crystal diffraction method. Crystallographic data. C22H26N8S2, Mr=466.62, monoclinic, space group C2/c,a=12.215(3), b=11.473(2), c=17.032 (3)Å, β=98.96(2)°, V=2357.7(9)Å3, Z=4, Dc=1.32 g/cm3, F(000)=1040, μ(Mo Kα)=2.43 cm−1. Final R=0.050, Rw=0.061 for 1103 unique and observed reflections with I ≥ 3σ(I). The effect of the structures on the formation of the open‐chain intermediates during the cyclization of (2:2) Schiff base macrocyclic compound has been discussed and a possible mechanism for the ring closure has been suggested.
Fluorescence study on the coaggregating tendencies of the cholesterols—the culprits of arteriosclerosis
Authors: Zhang Jin‐Tao , Ji Guo‐Zhen , Jiang Xi‐Kui 
Published: September 2010

AbstractThe coaggregating tendencies of the culprits of arteriosclerosis, the cholesteryl esters (CE‐n's), have been investigated in the 40:60 V/V (Φ = 0.40) dioxane (DX)‐H2O system, by using decyl pyrenyl ketone (Py‐11) as the fluorescence probe. The fluorescence intensity of Py‐11 decreases when coaggregation occurs between CE‐n and Py‐11, because of the low polarity of the microenviroment of the coaggregates. The order of the coaggregating tendencies obtained from the fluorescence data is in full agreement with that from the kinetic method, i.e., CE‐ol, CE‐ln > CE‐12 > CE‐8 > CE‐18 > CE‐0.
Synthesis of Imidazothiazole–Chalcone Derivatives as Anticancer and Apoptosis Inducing Agents
Authors: Kamal Ahmed , Dastagiri D. , Ramaiah M. Janaki , Reddy J. Surendranadha , Bharathi E. Vijaya , Srinivas Chatla , Pushpavalli S. N. C. V. L. , Pal Dhananjaya , Pal‐Bhadra Manika 
Published: September 2010

AbstractA new class of imidazo[2,1‐b]thiazole chalcone derivatives were synthesized and evaluated for their anticancer activity. These chalcone derivatives show promising activity, with log GI50 values ranging from −7.51 to −4.00. The detailed biological aspects of these derivatives toward the MCF‐7 cell line were studied. Interestingly, these chalcone derivatives induced G0/G1‐phase cell‐cycle arrest, down‐regulation of G1‐phase cell‐cycle regulatory proteins such as cyclin D1 and cyclin E1, and up‐regulation of CDK4. Moreover, these compounds elicit the characteristic features of apoptosis such as enhancement in the levels of p53, p21, and p27, suppression of NF‐κB, and up‐regulation of caspase‐9. One of these chalcone derivatives, 3 d, is potentially well suited for detailed biological studies, either alone or in combination with existing therapies.
Applying weak equivalence of categories between partial map and pointed set against changing the condition of 2‐arms bandit problem
Authors: Niizato Takayuki , Gunji Yukio‐Pegio 
Published: September 2010

AbstractThe main interest of the organizational learning is that the agent balances between exploring and exploiting. When the agent decides the answer in finite time, it gives rise to the problem that is trade‐off between exploring and exploiting. This problem never arises in the given enough time. The agent must decide answer from his imperfect information, when the time is given finite for the task. 2‐arms bandit problem is often taken into consideration in this problem. In previous article, we proposed the model for weak identity that is dynamically changing the hierarchy of his knowledge. Recently, the method of the heuristic model is attracted to approach this problem. In this article, we proposed different approaches for 2‐arms bandit problem, and the model we proposed can adapt to the environment when the condition of the problem is changed and shows another approach to the organizational learning. © 2010 Wiley Periodicals, Inc. Complexity 16: 10‐21, 2011
How corporate social responsibility information influences stakeholders' intentions
Authors: Alniacik Umit , Alniacik Esra , Genc Nurullah 
Published: September 2010

AbstractThe study shows how positive and negative information on corporate social and environmental responsibility influences purchase, employment, and investment intentions of various stakeholders. We manipulated the information on corporate social responsibility (CSR) activities of a hypothetical firm in a between‐subjects experimental design. The design had two treatments. In the ‘positive CSR’ treatment, the company's social and environmental performance was described in a positive perspective (depicting a strong social performance), whereas in the ‘negative CSR’ treatment it was described in a negative perspective (depicting a weak social performance). In both treatments, information about other key characteristics of the focal company were kept constant. Respondents' intentions to purchase products from, seek employment with, and invest in the company were evaluated by multi‐item scales. The results demonstrate that positive CSR information about a firm enhances consumers' intentions to purchase products from, potential employees' intentions to seek employment with, and potential investors' intentions to invest in the company. Theoretical and managerial implications of the findings are discussed. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
A linear, ultra wideband, low‐power, 2.1–5 GHz, VCO
Authors: Tsitouras Athanasios , Plessas Fotis , Kalivas Grigorios 
Published: September 2010

AbstractA linear, Ultra Wideband, low‐power VCO, suitable for UWB‐FM applications is proposed, forming the main part of a UWB‐FM transmitter. The VCO is designed in TSMC 90thinspacenm digital CMOS process and includes a Source‐Coupled Multivibrator, used as current‐controlled oscillator (CCO) which generates output frequencies between 2.1 and 5 GHz and a voltage‐to‐current (V‐to‐I) converter which translates the VCO input voltage modulation signal to current. Two single‐ended inverter buffers are employed to drive either a differential or a single‐ended UWB antenna. The presented VCO is designed for 1 V power supply and exhibits a linear tuning range of 2.1–5 GHz, a differential output power of −7.83 dBm±0.78 dB and low power consumption of 8.26 mW, including the output buffers, at the maximum oscillation frequency. It is optimized for a very high ratio of tuning range (81.69%) over power consumption equal to 9.95 dB. The desired frequency band of 3.1–5 GHz for UWB‐FM applications is covered for the entire industrial temperature range (−40 to 125∘C). Copyright © 2010 John Wiley & Sons, Ltd.
Historical perspective on mitochondrial medicine
Authors: DiMauro Salvatore , Garone Caterina 
Published: September 2010

AbstractIn this review, we trace the origins and follow the development of mitochondrial medicine from the premolecular era (1962–1988) based on clinical clues, muscle morphology, and biochemistry into the molecular era that started in 1988 and is still advancing at a brisk pace. We have tried to stress conceptual advances, such as endosymbiosis, uniparental inheritance, intergenomic signaling and its defects, and mitochondrial dynamics. We hope that this historical review also provides an update on mitochondrial medicine, although we fully realize that the speed of progress in this area makes any such endeavor akin to writing on water. © 2010 Wiley‐Liss, Inc. Dev Disabil Res Rev 2010;16:106–113.
The use of neuroimaging in the diagnosis of mitochondrial disease
Authors: Friedman Seth D. , Shaw Dennis W. W. , Ishak Gisele , Gropman Andrea L. , Saneto Russell P. 
Published: September 2010

AbstractMutations in nuclear and mitochondrial DNA impacting mitochondrial function result in disease manifestations ranging from early death to abnormalities in all major organ systems and to symptoms that can be largely confined to muscle fatigue. The definitive diagnosis of a mitochondrial disorder can be difficult to establish. When the constellation of symptoms is suggestive of mitochondrial disease, neuroimaging features may be diagnostic and suggestive, can help direct further workup, and can help to further characterize the underlying brain abnormalities. Magnetic resonance imaging changes may be nonspecific, such as atrophy (both general and involving specific structures, such as cerebellum), more suggestive of particular disorders such as focal and often bilateral lesions confined to deep brain nuclei, or clearly characteristic of a given disorder such as stroke‐like lesions that do not respect vascular boundaries in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke‐like episode (MELAS). White matter hyperintensities with or without associated gray matter involvement may also be observed. Across patients and discrete disease subtypes (e.g., MELAS, Leigh syndrome, etc.), patterns of these features are helpful for diagnosis. However, it is also true that marked variability in expression occurs in all mitochondrial disease subtypes, illustrative of the complexity of the disease process. The present review summarizes the role of neuroimaging in the diagnosis and characterization of patients with suspected mitochondrial disease. © 2010 Wiley‐Liss, Inc. Dev Disabil Res Rev 2010;16:129–135.
Molecular genetics of mitochondrial disorders
Authors: Wong Lee‐Jun C. 
Published: September 2010

AbstractMitochondrial respiratory chain (RC) disorders (RCDs) are a group of genetically and clinically heterogeneous diseases because of the fact that protein components of the RC are encoded by both mitochondrial and nuclear genomes and are essential in all cells. In addition, the biogenesis, structure, and function of mitochondria, including DNA replication, transcription, and translation, all require nuclear‐encoded genes. In this review, primary molecular defects in the mitochondrial genome and major classes of nuclear genes causing mitochondrial RCDs, including genes underlying mitochondrial DNA (mtDNA) depletion syndrome, as well as genes encoding RC subunits, complex assembly genes, and translation factors, are described. Diagnostic methodologies used to detect common point mutations, large deletions, and unknown point mutations in the mtDNA and to quantify mutation heteroplasmy are also discussed. Finally, the selection of nuclear genes for gold standard sequence analysis, application of novel technologies including oligonucleotide array comparative genomic hybridization, and massive parallel sequencing of target genes are reviewed. © © 2010 Wiley‐Liss, Inc. Dev Disabil Res Rev 2010;16:154–162.