bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Bacteria‐Virus Interaction on Mechanism of Virus Removal Using Microfiltration Membranes
Authors: Madaeni S. S. , Khodadadi B. 
Published: May 2015

AbstractIn this study, 0.22 μm hydrophobic GVHP membrane was challenged with host bacteria, Escherichia coli (ED 8656) and bacteriophage (λ wild type).For investigation of filtration mechanism, we employed blocking laws, which are based on the profiles of t/v versus time (t) and t/v versus volume (v). For prominent demonstrating the linearity, the profiles were reconstructed.When feed contained bacteriophage or a mixture of bacteriophages and host bacteria, the profiles indicated that at the beginning of the filtration, standard blocking (pore plugging) was the dominant mechanism. Over time the bacteriophages filled the pores and formed a cake layer on the membrane surface. The presence of bacteria facilitated the cake layer build up. Nevertheless the filtration mechanism started with pore blockage and ended with cake formation.The comparison of the present study with another research project carried out by the authors indicates that the removal mechanisms do not rely upon the interactions between microorganisms. However the details of cake layer specifications depend on the nature of the microorganisms and operating conditions.
Reduction of Aromatic Nitro Compounds under Solvent‐Free Conditions Using Alumina‐Supported Hydrazine/FeNH4(SO4)2·12H2O
Authors: Zhang Chang‐Rui , Wang Yu‐Lu , Wang Jin‐Ye 
Published: May 2015

AbstractAromatic nitro compounds were easily reduced to the corresponding amino compounds with hydrazine hydrate supported on alumina in the presence of FeNH4(SO)2·12H2O.
Experiments and Calculations on Photoionization and Dissociative Photoionization of CH2CO
Authors: Chiang Su‐Yu , Fang Yung‐Sheng , Bahou Mohammed , Sankaran K. 
Published: May 2015

AbstractThe dissociative photoionization of molecular‐beam cooled CH2CO in a region of ˜10–20 eV was investigated with photoionization mass spectrometry using a synchrotron radiation as the light source. Photoionization efficiency curves of CH2CO+ and of observed fragment ions CH2+, CHCO+, HCO+, C2O+, CO+, and C2H2+ were measured to determine their appearance energies. Relative branching ratios as a function of photon energy were determined. Energies for formation of these observed fragment ions and their neutral counterparts upon ionization of CH2CO are computed with the Gaussian‐3 method. Dissociative photoionization channels associated with six observed fragment ions are proposed based on comparison of determined appearance energies and predicted energies. The principal dissociative processes are direct breaking of C=C and C‐H bonds to form CH2+ + CO and CHCO+ + H, respectively; at greater energies, dissociation involving H migration takes place.
Geometry Optimization of Ba2+(H2O)n Clusters Using a Fast Hybrid Global Optimization Algorithm
Authors: Cao Yi‐Lin , Wang Yan‐Song 
Published: May 2015

AbstractA global optimization called fast hybrid global optimization algorithm was proposed based on genetic algorithm, fast simulated algorithm and conjugated gradient algorithm. We employ it to search the global minimum energy structures of Ba2+(H2O)n clusters for n = 1–30 within the TIP4P model. The results show that Ba2+(H2O)n clusters have the n+0 structure while n = 1–8. When n is in the range 9 ≤ n ≤ 18, the number of water molecules in the first shell around the barium ion is 8 and the other water molecules arrange in the outer shell. In the global minimum structure of Ba2+(H2O)19, the number of the first shell water molecules adds up to 9, and the value is kept until n = 30. According to the computational results, a conclusion that hydration numbers for Ba2+ is 9 can be drawn, which is in agreement with the result by a Monte Carlo simulation.
Assembly and Photophysics of Ternary Luminescent Lanthanide Molecular Complex Systems
Authors: Yan B. , Xie Q. Y. 
Published: May 2015

AbstractIn this paper, according to the molecular fragment principle, a series of eight ternary luminescent lanthanide complex systems were assembled, and whose compositions were determined with elemental analysis and infrared spectrum: Ln(MA)3(L)·H2O, where Ln = Sm, Eu, Tb, Dy; HMA = α‐methylacrylic acid; L = 1,10‐phenanthroline (phen), 2,2′‐bipyridine (bipy). The photophysical properties of these functional molecular systems were studied with ultraviolet‐visible absorption spectrum, and fluorescence excitation and emission spectrum. It was found that the heterocylic compounds (phen and bipy) act as the main energy donor and luminescence sensitizer for their suitable energy match and effective energy transfer to the emission energy level of Ln3+ ions. MMA ligand was only used as the terminal structural ligand to influence the luminescence. Especially terbium complex systems show the strongest luminescence for the optimum energy match and transfer between phen (bipy) and Tb3+ ion.
Separation of Iron(III) with Ammonium Thiocyanate‐H2O‐n‐Propyl Alcohol Extraction System in the Presence of Sodium Chloride
Authors: Wang Shaomei , Li Quanmin , Bai Haixin , Liu Guoguang 
Published: May 2015

AbstractThe behavior and conditions of liquid‐liquid extraction‐separation of Fe(III) by ammonium thiocyanate‐H2O‐n‐propyl alcohol system in the presence of NaCl were studied, and the possible reactive mechanism of extraction of Fe(III) was deduced. The study showed that, in the presence of a given amount of NaCl, phases were separated thoroughly between n‐propyl alcohol and water. In the process of phase separation, the complex [Fe(SCN)n](3‐n) formed by NH4SCN and Fe(III) was quantitatively extracted into the n‐propyl alcohol phase. The extracted Fe(III) exists in the n‐propyl alcohol phase mainly as the forms of Fe(SCN)2+ and Fe(SCN)3. Also, the relationship between extraction yield of Fe(III) and the amount of NH4SCN agreed well with the quadratic equation E = 0.54 + 58.14x − 8.39x2 (E and x represent the recovery rate of Fe(III) and the volume (mL) of 0.1 M NH4SCN respectively). The quadratic R‐Square is 0.9990. With this method, Fe(III) can be completely separated from Co(II), Ni(II), Mn(II), Al(III), Bi(III) and Cd(II) at pH 1.0˜2.0. The present method was applied in determining Fe(III) in samples with satisfactory results such as relative standard deviation from 2.06% to 2.89% and recovery rate in the range of 98.4˜101.4%.
Synthesis and Characterizations of Ti(O‐i‐Pr)Cl3(THF)(PhCOR) (R = H, Me, Ph) and Ti(O‐i‐Pr)Cl3(PhCOR)2 (R = Me, Ph). The Molecular Structure of Ti(O‐i‐Pr)Cl3(PhCOPh)2
Authors: Sheen Wen‐Shoei , Kuo Chun‐Nan , Hsieh Sheng‐Hsiang , Gau Han‐Mou 
Published: May 2015

AbstractA series of titanium(IV) complexes Ti(O‐i‐Pr)Cl3(THF)(PhCOR) (R = H (1), CH3 (2), or Ph (3)) is prepared quantitatively from reactions of [Ti(O‐i‐Pr)Cl2(THF)(μ‐Cl)]2 with 2 molar equiv. PhCOR. Treatment of Ti(O‐i‐Pr)Cl3 with 2 molar equiv. of PhCOR affords the disubstituted complexes Ti(O‐i‐Pr)Cl3(PhCOR)2 (R = CH3 (4) or Ph (5)). The 13C NMR study of these complexes shows that the relative bonding abilities are in the order of PhCOCH3 > PhCHO > PhCOPh. The molecular structure of 5 reveals that one of the benzophenone ligands is trans to the strongest 2‐propoxide ligand with a long Ti‐O(carbonyl) distance of 2.193(5) Å which is much longer than the other Ti‐O(carbonyl) distance of 2.097(4) Å by ˜0.1 Å. All ligands cis to the alkoxide ligand are bending away from the alkoxide ligand with the RO‐Ti‐L angles ranging from 93.6(2) to 99.0(2)°.
Depolymerization Study of Pakistani Coal in a Hydrogen Atmosphere. Effect of Operating Conditions
Authors: Ahmad Imtiaz , Khan Mohammad Arsala , Shakirullah Mohammad , Ishaq Mohammad , Ahmad Rashid , Habib‐ur‐Rehman  
Published: May 2015

AbstractA Pakistani coal was de‐polymerized/liquefied in toluene in a 1000 mL micro autoclave. Experiments have been performed in a pool of hydrogen under varying operating conditions of temperature, residence time, hydrogen pressure (cold), coal/solvent ratio and coal particle size. A pronounced effect of all these process variables has been noted on the yields of liquefied products, i.e., THF solubles, n‐pentane solubles, and n‐pentane insolubles. Extraction temperature of 450 °C, residence time of 1 hour, hydrogen pressure of 30 kgf/cm2, coal/solvent ratio of 1:2 and coal particle size of 53–45 μm were found optimum for maximum conversion of Pakistani coal into liquefied products.
Depolymerization Study of Pakistani Lignite Coal Influence of Pre‐treatments on Product Slate
Authors: Ahmad Imtiaz , Khan M. Arsala , Shakirullah M. , Ishaq M. , Iqbal Yousaf , ur Rehman Saeed 
Published: May 2015

AbstractInfluence of pretreatments, i.e., demineralization and pre‐soaking in some solvents on the yields of liquefied products obtained from hydro‐depolymerization of Pakistani coal in a pool of hydrogen has been discussed. Results of hydrogenation experiments demonstrated that demineralizing the coal sample prior to liquefaction caused the yields to decrease compared with the virgin coal samples. The contribution of mineral matter of coal has been evaluated by comparing the yields of liquid products of virgin and leached samples. Increase in the yields obtained from the hydrogenation experiments of swollen coal samples was not satisfactorily significant.
Separation and Kinetic‐Spectrophotometric Determination of Ketoconazole from Formulations Using SDS‐Coated Al2O3and KMnO4 in Alkaline‐SDS Micellar Medium
Authors: Farhadi Khalil , Bonab Hossein Sheikhloei 
Published: May 2015

AbstractA kinetic method for the accurate and sensitive determination of Ketoconazole (KC) has been described. The method is based on the alkaline oxidation of KC with KMnO4 in micellar SDS medium. At a fixed time of 8 min, the formed manganate ion is spectrophotometrically measured at 610 nm. The determination of KC by the fixed‐concentration and rate constant methods is feasible with the calibration equation obtained, but the fixed time method proves to be more applicable. The proposed method was successfully used for the quantitative determination of KC in formulations after the complete separation of KC using SDS‐coated Al2O3 as a suitable solid‐phase extraction system in comparison to liquid‐liquid extraction using poisonous organic solvents. Beer's law was obeyed from 0.4 to 28 μg mL−1 and the RSD% values for tablet, cream and shampoo samples were 1.8, 1.4 and 2.3, respectively. The results obtained agreed with those obtained by the USP method.
Synthesis and Characterization of Base‐catalyzed Phenyl Modified PDMS/PHMS Copolymers
Authors: Yang Mei‐Hui , Liu Hsin‐Wang , Lin Hsin‐Tso 
Published: May 2015

AbstractA series of phenyl modified polydimethylsiloxane (PDMS) / polyhydrogenmethylsiloxane (PHMS) random copolymers containing both internal Si‐H and terminal SiH2 and T (MeSiO3/2) units was synthesized in one step through n‐BuLi‐catalyzed ring‐opening polymerization of cyclic comonomers and characterized by GPC, IR and 1H and 29Si NMR. Sequential microstructures of these copolymers were determined by 29Si‐NMR spectroscopy. Epoxy‐modified polysiloxanes were prepared and used as comparable standards for the assignment of the NMR spectra. A hydride‐transfer mechanism has been proposed to account for the formation of terminal Si‐H and T group. Detailed sequential analyses and chemical shifts of 29Si‐NMR for various siloxane units are reported for the first time.
Solvent Effect of Dimethyl Sulfoxide on the Chemical Shifts of Phenyl Vinyl Ketones
Authors: Lien Jin‐Cherng , Chen Sheng‐Chih , Huang Li‐Jiau , Kuo Sheng‐Chu 
Published: May 2015

AbstractIn our study on the 1D and 2D NMR spectra of synthetic chalcones in DMSO‐d6, we found that, contrary to our expectation, the signals of α‐carbon correlated to the olefinic protons resonating at lower field whereas the signals of β‐carbon correlated to the olefinic protons resonating at higher field in the spectra of chalcones. To further investigate such solvent effect, four α,β‐unsaturated ketones were prepared and studied separately in CDCl3 and DMSO‐d6. The result indicated that the α,β‐unsaturated ketones that possess benzoyl moiety experienced solvent effect in DMSO‐d6 to result in an anomalous chemical shift. The shift arose from the complexation of solute molecule with DMSO that fixed the steric conformation of solute molecule so that Hβ was kept apart from its benzene ring whereas its Hα became more accessible by its benzene ring. Thus, these two olefinic protons would experience a different extent of anisotropic effect exerted by the neighboring benzene ring.
A Facile Access to Polysubstituted Bipyrazoles and Pyrazolylpyrimidines
Authors: Dawood Kamal M. , Farag Ahmad M. , Ragab Eman A. 
Published: May 2015

Abstract3‐(Pyrazol‐3‐yl)‐3‐oxo‐propanenitrile derivative reacts with several nitrogen nucleophiles to give bipyrazole, pyrazolyloxazole, and pyrazolylpyrimidine derivatives. The structures of the products were confirmed on the basis of their elemental and spectral analyses.
Phenylpropanoid Glycosides from the Parasitic Plant, Aeginetia Indica
Authors: Ho Jiau‐Ching , Chen Chiu‐Ming , Li Zhi‐Qiang , Row Lie‐Ching 
Published: May 2015

AbstractTwo new phenylpropanoid glycosides, α‐L‐rhamnopyranosyl‐(1→3)‐1‐O‐caffeoyl‐β‐D‐glucopyrano‐side and 2″,3″′‐diacetyl acteoside, together with seven known compounds have been isolated from the parasitic plant, Aeginetia indica Linn. Their structures were established by spectroscopic and chemical methods.
Discovery of Recurrent Structural Motifs for Approximating Three‐Dimensional Protein Structures
Authors: Soong Ta‐Tsen , Hwang Ming‐Jing , Chen Chung‐Ming 
Published: May 2015

AbstractThe scope of conformation space that protein molecules can adopt is a problem of significant interest. Previous studies by other groups have shown that there are stereochemical constraints that confine local protein structures to a limited range of conformations. Furthermore, the results of many groups have demonstrated that the sequence‐to‐structure relationship remains detectable to some extent on a local level. By studying the conformational space of local protein structures, we may obtain more information concerning the constraints on local structural space and the sequence‐to‐structure mapping, hence facilitate ab initio structure prediction. In this study, we propose a novel algorithm that automatically discovers recurrent pentamer structures in proteins.The algorithm starts by applying Expectation‐Maximization (EM) clustering to the distances between non‐adjacent backbone Cα atoms in a large set of pentamer fragments. A rough partition of the conformation space can thus be derived. In the second stage, by applying a split‐and‐merge algorithm, we can obtain a finite number of clusters and guarantee the homogeneity and distinctiveness of each one. Each cluster of protein structures is represented by a centroid structure. The results show that, with 40 major representative structures, we can approximate most of the protein fragments with an error of 0.378 Å. With only 20 types of structures, the fragment structures can still be modeled at 0.44 Å, which is comparable to or better than the performance of previous methods. We term the representatives “building blocks.” On the global level, we demonstrate that by concatenating different combinations of building blocks, we can model whole protein structures at high resolution: a resolution of 2.54 Å can be achieved simply by using 10 types of building blocks. This finding suggests that the study of molecular structures can be hugely simplified using this reduced representation.
Ligand Binding Subsequent to NO Photolyses of Partially Unfolded Cytochrome c
Authors: Mikšovská Jaroslava , Larsen Randy W. 
Published: May 2015

AbstractHere we report folding studies of horse heart ferricytochrome c in the presence of NO (NO‐cyt c). The midpoint concentration of guanidine hydrochloride (GuHCl) for unfolding was measured to be 2.8 M in the presence of NO and is only moderately altered relative to native cyt c under similar conditions (i.e., 2.6 M GuHCl). Recombination of NO to cyt c in the presence of 2.8 M GuHCl subsequent to photolysis is biphasic with rate constants of (4.24 ± 0.15) × 103 s−1 and 197.7 ± 3.3 s−1 with the fast and slow phase representing ˜60% and 40% relative amplitudes, respectively. NO rebinding to unfolded cyt c (in the presence of 4 M GuHCl) exhibits two phases with rate constants similar to those observed in the presence of 2.8 M GuHCl with the relative amplitude of the fast phase increasing to roughly 90%. These data suggest that NO rebinds to two populations of cyt c with one population containing a five coordinate heme and the other having a six‐coordinate heme with bis‐His axial ligation. These results suggest that the mis‐ligated bis‐His conformation forms rapidly during the refolding of cyt. c3+, although a population exists that can refold down a native pathway.
Competition Between Transcription Factors and Histones, and the Role of the Histone H3 Amino Terminus, During Gene Regulation in Budding Yeast
Authors: Yu Liuning , Yu Cailin , Stafford Grace , Morse Randall H. 
Published: May 2015

AbstractDNA in eukaryotes is packaged into chromatin by association with the four histone proteins, H2A, H2B, H3, and H4, to form nucleosomes. Transcription factors must recognize particular DNA sequences to activate genes and so must compete with the histones for occupancy of their cognate binding sites. Beyond this repressive role, the histones have also adopted regulatory roles, both positive and negative, which are largely mediated by amino terminal “tails” that do not contribute to the basic structure of the nucleosome. Here, we describe some of our recent progress in understanding how transcription factors compete with histones for binding site occupancy and also discuss recent results on the global role of the histone H3 amino terminus in regulating gene expression in the budding yeast Saccharomyces cerevisiae.
Experimental and Computational Studies of the Isomerization between Z and E Isomers of Benzaldoximes
Authors: Xu Weiren , Wang Jianwu , Liu Chengbu , Chen Cheng‐Lung 
Published: May 2015

AbstractThe isomerization between Z and E isomers of benzaldoximes in different solvents were measured by TLC method. The experimental results show that acid solvents catalyze this inter‐conversion process dramatically. Solution state NMR measurements also show very different spectra for Z and E isomers of benzaldoximes in different solvents. All this suggests that the acidity of solvent is a very important factor to affect the inter‐conversion process.Theoretical investigations of Z to E inter‐conversion of benzaldoximes in different solvents were carried out by DFT calculations at B3LYP/6–3 11+G** level. The calculations show that the barrier from Z to E in the presence of acid is much lower than that without acid. This agrees with the experimental data very well. The calculated structure in the transition state is helpful for the understanding of the inter‐conversion mechanism.
A New Synthesis of Benzofurans from Phenols via Claisen Rearrangement and Ring‐Closing Metathesis
Authors: Tsai Tzu‐Wei , Wang Eng‐Chi , Li Sie‐Rong , Chen Yung‐Hua , Lin Yu‐Li , Wang You‐Feng , Huang Keng‐Shiang 
Published: May 2015

AbstractBased on Claisen rearrangement, the double bond isomerization of O‐allyl function together with the formation of O‐vinyl function in one pot, and ring‐closing metathesis (RCM), various phenols were transformed into various benzofurans in good yields.
A Convenient Synthesis and Pharmacological Activity of Novel Annelated Pyrimidine Derivatives
Authors: Aly A. A. 
Published: May 2015

AbstractSimple and convenient synthesis for a series of 2,3‐diglycosylpyrimidine 4, pyrazolo[3,4‐d]pyrimidine 8, ditetrazolo[1,5‐a;1′,5′‐c]pyrimidine 9, 2,9a,10‐triazaanthracene 12, thieno[2,3‐d]pyrimidine 14, 1,3,5,7‐tetraazafluorene‐8‐one 15, 1,3,5‐triazafluorene‐8‐one 16, 1,3‐diazafluorene 21a,b derivatives have been synthesized via a sequence of heterocyclization reactions of suitably functionalized 6‐[5‐(4‐bromophenyl)ox‐azol‐4‐yl]‐4‐oxo‐2‐thioxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carbonitrile (2) with different electrophiles and nucleophiles. The new compounds were prepared with the objective to study their pharmacological properties.
Clavulazols A and B, Two New Pyrazine Derivatives from Clavularia Viridis
Authors: Shen Ya‐Ching , Wang Li‐Tang , Cheng Yuan‐Bin , Khalil Ashraf Taha , Chen Meng‐Hsien , Lin Yu‐Chi 
Published: May 2015

AbstractTwo new marine pyrazine derivatives, clavulazols A (4) and B (5), were isolated from ethyl acetate extract of the soft coral Clavularia viridis collected in Taiwan. The structures were determined on the basis of spectral analysis, especially 2D NMR as well as chemical conversion.
Cerebrosides from the Rhizomes of Gynura Japonica
Authors: Lin Wei‐Yu , Yen Ming‐Hong , Teng Che‐Ming , Tsai Ian‐Lih , Chen Ih‐Sheng 
Published: May 2015

AbstractFour new cerebrosides, gynuramides I˜IV (1‐4), together with 37 known compounds were isolated from the rhizome of Gynura japonica. The structures of cerebrosides 1‐4 were determined by chemical and spectroscopic examination to be: (2S,3S,4R,8E)‐2‐[(R)‐2‐hydroxypentacosanoylamino]‐8‐en‐1,3,4‐octadecanetriol, (2S,3S,4R,8E)‐2‐[(R)‐2‐hydroxytetracosanoylamino]‐8‐en‐1,3,4‐octadecanetriol, (2S,3S,4R,8E)‐2‐[(R)‐2‐hydroxytricosanoylamino]‐8‐en‐1,3,4‐octadecanetriol, and (2S,3S,4R,8E)‐2‐[(R)‐2‐hydroxydocosanoylamino]‐8‐en‐1,3,4‐octadecanetriol.
External Electric Field Effects on Emission of a Mixture of Tetraphenylporphyrin and Fullerene Doped in a Polymer Film
Authors: Wahadoszamen MD. , Nakabayashi Takakazu , Ohta Nobuhiro 
Published: May 2015

AbstractIn a mixture of tetraphenylporphyrin (TPP) and fullerene (C60) doped in a PMMA film, fluorescence of TPP is enhanced and de‐enhanced by an electric field in zinc and free‐base compounds, respectively, indicating that the electron transfer from the excited state of TPP to C60 is decelerated in zinc compounds and accelerated in free‐base compounds by an electric field. TPP was found to form complex upon mixing with C60 which exhibits a broad emission in the wavelength region longer than that of the TPP emission. The complex emission is significantly quenched by an external electric field in both zinc and free base compounds, suggesting that the nonradiative decay of the excited complex is accelerated by an electric field in both cases.
Theoretical Treatments of Radiationless Transitions
Authors: Chin C. H. , Shiu H.Y.‐J. , Wang H.‐W. , Chen Y.‐L. , Wang C.‐C. , Lin S. H. , Hayashi M. 
Published: May 2015

AbstractIn this review, we present a microscopic theory for describing photo‐induced radiationless transitions. For this purpose, we state that introducing the density matrix method can not only treat the dynamics due to the radiationless transitions but also deal with the population and coherence dynamics. We briefly review several rate constants of the radiationless transitions and the analytic estimation methods of those rate constants. Finally, we present the applications of the theoretical treatment to the rapid electron transfer and energy transfer taking place in the photosynthetic reaction centers.
Aggregation‐Induced Emission of 4‐Dicyanomethylene‐2,6‐Distyryl‐4H‐pyran
Authors: Tong Hui , Häußler Matthias , Dong Yong‐Qiang , Li Zhen , Mi Bao‐Xiu , Kwok Hoi‐Sing , Tang Ben‐Zhong 
Published: May 2015

AbstractA new pyran (1) is synthesized. When molecularly dissolved in acetone, 1 is practically nonemissive. Addition of water induces it to cluster into nanoaggregates, which turns its emission “on” and boosts its luminescence efficiency dramatically. The color of its emission changes from green to red upon aggregation.