bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Situ Silication of Polymer Nanofibers to Engineer Multi‐Biofunctional Composites
Authors: Meka Sai Rama Krishna , Kumar Verma Shailendra , Agarwal Vipul , Chatterjee Kaushik 
Published: April 2018

AbstractThe critical role of silica in bone homeostasis has motivated the development of silica‐based biomaterials for orthopedic applications. Whereas polymer nanofibers have emerged as promising substrates for orthopedic applications, nanoparticle agglomeration precludes the preparation of silica containing composite nanofibers by electrospinning. This work presents a facile sol‐gel process to fabricate electrospun nanocomposite fibers by in situ silica gelation in poly (ϵ‐caprolactone) (PCL) solution. Citric acid is shown to be more effective than acetic acid as the pH catalyst for gelation by rapidly yielding near uniform nanoparticles (150+50 nm). The composite nanofibers exhibited increased water wettability than neat PCL with sustained release of silicon ions. The composite fibers induced early apatite formation in simulated body fluid. Quantitative characterization of the tubular networks formed by human umbilical cord vascular endothelial cells revealed that the eluted silicon ions and citric acid in fibers synergistically promoted angiogenic activity, which was corroborated by increased gene and protein expressions of several known angiogenic markers. Furthermore, silicate fibers augmented osteogenesis of human mesenchymal stem cells as measured by the increased mineral deposition and increased gene and protein expression of osteogenic markers. Thus, the in situ silicated fibers are promising multi‐biofunctional materials for orthopedic applications.
Magnesium Bonds: From Divalent Mg Centres to Trigonal and Tetrahedral Coordination
Authors: Grabowski Sławomir J. 
Published: April 2018

AbstractωB97XD/aug‐cc‐pVTZ calculations were performed for MgXY complexes (X=Cl, Br; Y=Cl, Br, CH3, C2H5, C6H5) with one or two H2O or (CH3)2O ligands to mimic interactions of Grignard reagents in solvents. The magnesium Lewis acid centre interacts in these complexes with the Lewis base O‐centre and the corresponding Mg…O link may be classified as the magnesium bond (Mg‐bond). This interaction is characterized by properties similar to those of the hydrogen bond; however it also possesses few unique features. The Mg‐centres of isolated MgXY species are characterized by ring regions of a positive electrostatic potential (EP) that determines their acidic properties. The linear geometry of the MgXY unit is disturbed in complexes with H2O or (CH3)2O species where the Mg‐centres are closer to trigonal and to tetrahedral configurations in complexes with one and two ligands, respectively; such centres also possess regions of positive EP.
High Catalytic Behavior of Activated Carbon‐Supported K‐Fe‐Ni Based Catalysts for 1,6‐Hexanedinitrile Hydrogenation under Mild Conditions
Authors: Lv Yang , Liu Pingle , Hao Fang , Xiong Wei , Luo He'an 
Published: April 2018

AbstractActivated carbon supported potassium and iron doped nickel‐based catalysts were prepared and characterized by XRD, chemisorption of H2, H2‐TPR, XPS, N2 adsorption‐desorption analysis, NH3‐TPD, SEM, TEM, HRTEM and HAADF‐STEM. The catalytic behaviors were conducted on the hydrogenation of 1,6‐Hexanedinitrile to 6‐aminohexanenitrile and 1,6‐hexanediamine under 338 K‐358 K and 2 MPa hydrogen pressure. It can be deduced that the reducibility of the nickel oxide, the surface of the Ni0+ content and the dispersibility of nickel nanoparticles can be significantly enhanced by doping a certain amount of iron as the results of the synergetic effect between nickel and iron. Moreover, the introduction of potassium not only can effectively increase the alkaline site of the catalyst so as to inhibit the formation of by‐products, but also improve the dispersion of nickel nanoparticles by suppressing the sintering effect. However, the addition of excessive potassium is unfavorable to the nickel oxide reduction. It can be seen that activated carbon supported potassium and iron doped nickel‐based catalyst gives better catalytic performance of 91.32% conversion of 1,6‐Hexanedinitrile and 91.82% selectivity to 6‐aminohexanenitrile and 1,6‐hexanediamine under mild conditions of 348 K and 2 MPa.
One‐Pot Cascade Synthesis of 2‐Cyanoacrylamides via Sn‐Catalyzed Acetic Acid Free Selective Monohydration of Dinitrile
Authors: Shaikh Taufeekaslam M. Y. , Mulla Shafeek A. R. 
Published: April 2018

AbstractThe simple, mild, novel and an efficient new protocol has been developed for the straightforward synthesis of 2‐cyanoacrylamides. This is the first report in which Sn‐catalyzed acetic acid free selective monohydration of dinitrile was achieved for a one pot cascade synthesis of 2‐cyanoacrylamides in good to excellent yield via condensation of various aldehydes, heterocyclic aldehydes with malononitrile.
Silica‐Impregnated Polyphosphoric Acid Catalyzed an Eco‐Friendly Rapid Synthesis of Functionalized Tetrahydroquinolines and Quinazolin‐4‐ones in Water
Authors: Ansari Mohd. Imran , Hussain Mohd. Kamil , Hajela K. 
Published: April 2018

AbstractA metal‐free, mild, eco‐friendly and efficient method has been developed for the synthesis of functionalized tetrahydroquinolines, quinazolin‐4(1H)‐ones and quinazolin‐4(3H)‐ones using metal‐free and economically viable heterogeneous catalyst PPA‐SiO2 in water preferentially forming cis‐isomer. Both electron withdrawing and electron donating groups were found to be well tolerated and isolated products were obtained in good yields. Cis‐isomer was predominant in case of electron donating substrate in water.
Methanol Oxidation Reaction Performance on Graphene‐Supported PtAg Alloy Nanocatalyst: Contrastive Study of Electronic and Geometric Effects Induced from Ag Doping
Authors: Zhang Rui , Xia Wenfang , Kang Wenjun , Li Rui , Qu Konggang , Zhang Yingtian , Chen Baoli , Wang Huaisheng , Sun Yongfu , Li Haibo 
Published: April 2018

AbstractIn Pt‐based alloy catalyst, the electrocatalytic performance is highly related to the Pt d‐band center, whose position can be modulated by the synergetic interaction of electronic and geometric effects. In this study, graphene‐supported PtAg (PtAg/graphene) alloy nanocatalyst was prepared by a facile galvanic replacement reaction. Due to the introduction of Ag component, the PtAg/graphene exhibits a higher specific/mass activity (1.48 mA cm–2, 580 mA mgPt–1) and better CO tolerance (CO stripping potential: 0.45 V vs. Ag/AgCl) than those of commercial Pt/C catalyst (0.86 mA cm–2, 270 mA mgPt–1, 0.50 V vs. Ag/AgCl) when being applied for catalyzing methanol oxidation reaction (MOR). On the basis of component and structure characterization, the PtAg alloy catalyst model was constructed, and first‐principles density function theory calculation was applied to study the relative influence of electronic and geometric effects on the Pt d‐band center and CO binding energy, respectively. It is found that the electronic effect, i. e. the charge transfer from Ag to Pt, is the decisive factor to enhance the electrocatalytic performance of PtAg alloy towards MOR.
KCC‐1 Supported Cu(II)‐β‐Cyclodextrin Complex as a Reusable Catalyst for the Synthesis of 3‐Aryl‐2‐oxazolidinones from Carbon Dioxide, Epoxide, Anilines
Authors: Sadeghzadeh Seyed Mohsen , Zhiani Rahele , Moradi Marjan 
Published: April 2018

AbstractThis study investigated the potential application of an efficient, easily recoverable, and reusable KCC‐1 nanoparticle catalyst, which supported Cu (II)‐β‐cyclodextrin complex for 3‐aryl‐2‐oxazolidinones synthesis from CO2, ethylene oxide, and anilines. KCC‐1/β‐CD/Cu (II) NPs were thoroughly characterized by using TEM, SEM, TGA, FT‐IR, ICP‐MS, and BET. The observations were exploited in the direct and selective chemical fixation of CO2 to afford high degrees of CO2 capture and conversion. Analysis of the recycled catalyst by ICP‐MS revealed only minor changes in its morphology after the reaction and thus confirmed the robustness of the catalyst.
Exploring Solvent Effects on the Dialysis‐Induced Self‐Assembly of Nanostructured Tetra(aniline)
Authors: Lyu Wei , Yu Mengting , Feng Jiangtao , Yan Wei 
Published: April 2018

AbstractOne‐pot simple dialysis process was employed to explore the self‐assembly behavior of Ph/NH2‐capped tetra(aniline) (TANI) in five different solely organic solvents. Multi‐morphologies of supramolecular were assembled including nanoparticles, nanocapsules, hierarchical nanoflowers and nanowires. The solvent effects on the self‐assembly behavior were studied by differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), FT‐IR and UV‐Vis spectroscopies, 1H NMR and powder X‐ray diffraction (PXRD), as well as density functional theory (DFT) calculations. Investigations suggested that the increase of solvent polarity facilitated the formation of hydrogen bonding between solute‐solvate. Moreover, dialysis process was found to have a profound effect on forming intermolecular π‐π stacking interaction. Such results provided not only an insight into the formation mechanism and design rule of self‐assembly behavior of nanostructured oligo(aniline)s in organic solvent‐containing complex system, but also further understanding of dialysis‐induced self‐assembly system for other nanomaterials.
Biodiesel Production from Recycled Grease Trap Waste: A Case Study in South Australia. Part 2: Optimization of The Transesterification Process
Authors: Tran Nghiep N. , McMurchie Edward J. , Ngothai Yung 
Published: April 2018

AbstractThis study aimed to investigate the conversion of the pre‐treated oil, which was originally extracted from grease trap waste (GTW), to biodiesel via a transesterification reaction. The pre‐treated oil, which consists of approximately 80% free fatty acid ethyl esters (FAEEs) and 18% of glycerides, was obtained through the esterification of GTW reported in a previous study. Response Surface Methodology (RSM) based on Central Composite Design (CCD) was applied to determine the optimum conditions for the transesterification reaction through four process variables, these being: the molar ratio of ethanol to oil, reaction time, reaction temperature, and base catalyst loading. A set of 30 experiments were conducted in duplicate to study the interactive effects of the above parameters on the ester yield. A maximum ester yield of 96.7% was obtained at the optimum conditions, which were: 4:1 ethanol to oil molar ratio, 1 hr reaction time, 65 °C reaction temperature, and 1 wt% KOH loading per oil weight. In order to reduce the excess ethanol used, a modification was applied to the experimental design of the transesterification reaction, resulting in a 30% reduction in ethanol used, while the same ester yield could be obtained.
Insight of Diversified Reactivity and Theoretical Study of Mixed‐Phase Titanium Dioxide for the Photoactivation of Small Molecules
Authors: Olowoyo Joshua O. , Hernández Norge Cruz , Kumar Manoj , Jain Suman L. , Babalola Jonathan O. , Kumar Umesh 
Published: April 2018

AbstractThe mixed‐phase titanium dioxide (TiO2) nanoparticles were prepared by two different methods; sonothermal (S) and sonothermal followed by hydrothermal (SH). The TiO2 prepared by SH has shown a superior hydrogen (H2) generation via photocatalytic splitting of water (H2O) and formic acid (FA) as well as photocatalytic reduction of carbon dioxide (CO2) to methanol (MeOH). The H2 production rate under UVA from H2O and FA was 0.02 and 3.91 mmol g−1 h−1 respectively while MeOH formation rate was 1.97 mmol g−1 h−1 from CO2. The DFT calculations of the reactants and products were also investigated.
Experimental Analysis on the Probability Density Distribution of Methane Hydrate Induction Times in Porous Media
Authors: Wang Shanrong , Yang Mingjun , Li Kehan 
Published: April 2018

AbstractHydrate‐based natural‐gas transport and storage have been proposed and developed because of the high safety and low cost, and hydrate reformation is a serious barrier for high‐efficiency natural‐gas hydrate exploitation. The hydrate formation induction time is a crucial kinetic parameter for both of the two fields. To clarify the hydrate formation and/or reformation induction characteristics, the effects of sub‐cooling, particle size, initial water saturation and memory effect on the stochastic induction time patterns are experimentally investigated. In total, 22 cases were performed, and each case was repeated in 20–30 runs under identical conditions. The experimental results show that the distribution of CH4 hydrate induction times can be properly fitted to a lognormal distribution function. Larger sub‐cooling leads to shorter induction time and more repeatable experimental results. It is also found that shorter induction time and repeatable results can be obtained with bigger particle size. The experimental results show that 70% water saturation can be considered a critical value for hydrate formation. Memory effect of water is existed in the experiments, which can help reducing the induction time and its stochastic nature. It can be considered that the memory effect on the induction time is dominant compared with the other factors (sub‐cooling, particle size and initial water saturation).
Environmentally Benign Deep Eutectic Solvent for Synthesis of 1,3‐Thiazolidin‐4‐ones
Authors: Yedage Dattatray B. , Patil Dattatray V. 
Published: April 2018

AbstractThis paper explores the versatility and effectiveness of Deep Eutectic Solvent (DES) as an efficient catalyst cum reaction media for the preparation of biologically important 1,3‐ thiazolidin‐4‐one derivatives. This methodology was objected to overcome the limitations of the previously reported methods such as the use of expensive and toxic solvents, long reaction time and low yield. This protocol is rapid, environmentally benign, with good to high yield of products. The DES media could be reused up to five times without any appreciable decrease in the yield.
Synthesis and Structure of Ru(II) Complexes of Thiosemicarbazone: Highly Selective Catalysts for Oxidative Scission of Olefins to Aldehydes
Authors: Muthumari Subramanian , Ramesh Rengan 
Published: April 2018

AbstractNew Ru(II)‐TSC complexes of the type [RuH(TSC)(CO)(PPh3)2] (where TSC= monobasic bidentate anthracenealdehyde thiosemicarbazone ligands) were synthesized and characterized by means of elemental analysis, IR, UV−vis, and NMR spectral methods. Molecular structures of the complexes were determined by single crystal X‐ray crystallography, which prove the coordination mode of the ligands and reveal the presence of a distorted octahedral geometry around the Ru ion. The synthesized complexes were developed as catalysts for selective oxidative cleavage of a wide range of alkenes as well as alkynes to the corresponding aldehydes/ diketones in acetonitrile/ water in the presence of NaIO4 at room temperature. The maximum yield was obtained up to 99% using 0.5 mol% of catalyst loading without any over oxidation byproducts. The effect of substituents of the ligand, solvents, reaction temperature and catalyst loading on the catalytic activity of the complexes is also investigated.
2,4‐Disubstituted Phenylhydrazonopyrazolone and Isoxazolone Derivatives as Antibacterial Agents: Synthesis, Preliminary Biological Evaluation and Docking Studies
Authors: Oraby Ahmed K. , Abdellatif Khaled R. A. , Abdelgawad Mohamed A. , Attia Khadiga M. , Dawe Louise N. , Georghiou Paris E. 
Published: April 2018

AbstractA series of new 2,4‐ disubstituted phenylhydrazonopyrazolone and isoxazolones have been synthesized and evaluated for antibacterial activity. These compounds incorporated the bioactive moieties 3‐methyl isoxazolone and 3‐methyl pyrazolone. Based on the preliminary results, evaluation of these new compounds as potential antimicrobial agents revelead that four of them which incorporate the isoxazolone moiety exhibited selective antimicrobial activity against Gram‐positive bacteria with MICs for S. aureus in the 50–100 μgmL−1 range. Additionally, docking studies were performed in order to explore the possible binding poses in the MurB protein of S. aureus and the results were correlated to the antimicrobial results reported herein.
Copper Catalyzed Regioselective N – Alkynylation of Pyrazoles and Evaluation of the Anticancer Activity of Ethynyl‐ Pyrazoles
Authors: Sau Mohan Chandra , Rajesh Y. , Mandal Mahitosh , Bhattacharjee Manish 
Published: April 2018

AbstractA copper‐catalyzed regioselective N‐alkynylation of unsymmetrically substituted pyrazoles from the reactions of pyrazoles with aromatic and aliphatic terminal alkynes under aerobic condition is reported here. The single crystal XRD structures of the N‐substituted pyrazoles confirm the regioselectivity. The cytotoxicity towards MDA‐MB 231 breast cancer cells of three of the alkynyl pyrazoles has been investigated.
Studies towards the Total Synthesis of Aspergillide‐B
Authors: Bhavani Kanugula , GyanChander Eppa , Das Saibal , Yadav Jhillu Singh 
Published: April 2018

AbstractA formal, stereoselective synthesis of Aspergillide‐B is described. A highly diastereoselective Pd(0)‐B(OPh)3 mediated syn‐vic‐diol formation from epoxy unsaturated ester used for the creation of C3‐C4 centres. Iodine catalyzed allylation used for synthesis of trans‐2,6‐disubstitutedtetrahydro‐2H‐Pyran. Cross‐ metathesis, Yamaguchi macrolactonization are the other key features of the synthesis.
Methane Dissociation on Bimetallic AuNi3, Au2Ni2 and Au3Ni Clusters‐A DFT Study
Authors: Roy Ghanashyam , Chattopadhyay Asoke Prasun 
Published: April 2018

AbstractThe effect of gold atom for the dissociation of methane on tetrahedral bimetallic AuxNiy (x+y=4; x,y=1‐3) clusters are introduced using density functional theory method. The binding energy and HOMO‐LUMO gap fluctuate with odd‐even number of gold atoms. The clusters, AuNi3 and Au3Ni, containing odd number of doped gold atoms, which causes open shell configuration, are exceptionally stable and highly resistance to carbon deposition, whereas closed shell Au2Ni2 cluster is less stable. As the number of doped Au atom increases in the clusters, adsorption or binding energy of methane increases. The dissociation of methane is a four elementary steps process, and first step of dissociation, CH4→CH3, is not the rate determining step, and thermodynamically favorable at room temperature and pressure for the clusters due to adsorption. Whereas, the dissociation of CH→C, coke formation step 4, is the rate determining step due to highest energy barrier for all the clusters. The calculated activation energies for the rate determining step are 0.92 eV, 0.41 eV and 1.64 eV for AuNi3, Au2Ni2 and Au3Ni clusters, respectively. In addition, the dissociation temperature for all the intermediates, e. g., CH3, CH2 and CH are 450 K(CH3 and CH2) and 650 K(CH) on AuNi3 cluster; 450 K(CH3) and 550 K(CH2 and CH) on Au2Ni2 cluster; and 650 K(CH3), 750 K(CH2) and 950 K(CH) on Au3Ni cluster. Thus, the coke resistivity decreases as Au3Ni >AuNi3>Au2Ni2 and corresponding coke resistance temperatures are 950 K, 650 K and 550 K, respectively. The charge tranfer to the clusters during adsorption is negative, and is positive in the dissociation steps. Thus, the number of doped gold atom not only influences the stability of bimetallic Au−Ni clusters, but also their reactivity towards methane, which can provide some new insight for the design of coke resistant catalysts for methane reforming.
The Elaboration of a General Approach to the Asymmetric Synthesis of 1,4‐Substituted 1,2,3‐Triazole Containing Amino Acids via Ni(II) Complexes
Authors: Larionov Vladimir A. , Adonts Hovhannes V. , Gugkaeva Zalina T. , Smol'yakov Alexander F. , Saghyan Ashot S. , Miftakhov Mansur S. , Kuznetsova Svetlana A. , Maleev Victor I. , Belokon Yuri N. 
Published: April 2018

AbstractHerein we report a general method of the asymmetric synthesis of 1,4‐substituted 1,2,3‐triazole containing amino acids via copper(I) iodide catalyzed “click reaction” between azides and chiral Ni(II) complexes of Schiff bases of (S)‐ or (R)‐BPB with alkyne side chain derivatised amino acids. The final Ni(II) complexes were decomposed with aqueous HCl and the 1,4‐substituted 1,2,3‐triazole containing amino acids isolated with excellent enantioselectivities (>99% ee). The chiral auxiliary ligand (BPB=N‐benzyl proline benzophenone) can be recycled and reused for the synthesis of starting Ni(II) complexes.
Adsorption and Decomposition of DMMP on Size‐Selected (WO3)3 Clusters
Authors: Tang Xin , Hicks Zachary , Ganteför Gerd , Eichhorn Bryan W. , Bowen Kit H. 
Published: April 2018

AbstractThe adsorption and decomposition behaviors of dimethyl methylphosphate (DMMP) on size‐selected (WO3)3 clusters were studied by a combination of X‐ray Photoelectron Spectroscopy (XPS) and Temperature Programmed Reaction (TPR). The fate of DMMP adsorbed on (WO3)3 clusters was found to be very similar to its fate on (MoO3)3. In contrast to DMMP on (MoO3)3, however, dimethyl ether was observed as a product in the reaction of DMMP with (WO3)3, in addition to methanol, due to the higher Lewis acidity of (WO3)3 clusters as compared to (MoO3)3.
Structural Related Effects of Natural Steroid Molecules on Cholesterol Crystallization in Model Bile and Ethanol
Authors: Jing Jie , Wei Tongxin , Su Wenqiang , Liu Yonghai , Yao Weiwei , Zhu Huaxu , Fu Tingming 
Published: April 2018

AbstractThe purpose of the present experiment is to study the different effects of natural steroid molecules (NSM) on the crystallization of cholesterol in model bile and ethanol. Three natural steroids (stigmasterol, β‐sitosterol, and ergosterol) were selected as model molecules. The supernatant and precipitated crystals collected from 95% ethanol and model bile were quantitatively analyzed by high‐performance liquid chromatography‐evaporative light scattering detection (HPLC‐ELSD), powder X‐ray diffraction, and differential scanning calorimetry, as well as scanning electron microscope, were conducted to understand the crystalline properties of a substance. Results show that Stigmasterol and β‐sitosterol can increase the solubility of cholesterol in specific mass ratios under 95% ethanol system, and lower the solubility of cholesterol in model bile. Ergosterol, on the other hand, has no significant effect on cholesterol crystallization. The reason for this phenomenon is that phytosterols are more similar in molecular structure to cholesterol and act as co‐precipitates with cholesterol in both systems.
A High‐Performance Flexible Supercapacitor Anode Based On Polyaniline/Fe3O4 Composite@Carbon Cloth
Authors: Kumar Meenu P. , Lathika Lekshmi M. , Mohanachandran Anjana P. , Rakhi Raghavan Baby 
Published: April 2018

AbstractHerein, we report for the first time, the synthesis of a binder‐free flexible Polyaniline (PANI) and Iron Oxide (Fe3O4) nanocomposite (PANI/Fe3O4) electrode by the direct growth of active materials over carbon cloth. The carbon cloth substrate, with its three‐dimensional porous structure, provides more electrolyte accessibility and acts as an effective conductive pathway for efficient electrical transport between the active materials and the current collector. The PANI/Fe3O4 nanocomposite electrode exhibits a maximum specific capacitance of 365 F g−1 in a stable potential window ranging from −1 V to 0 V. Also it retains a cycling stability of 91% even after 4000 charge‐discharge cycles at a constant current density of 5 A g−1. These results indicate that PANI/Fe3O4 nanocomposite electrode has a significant potential as an inexpensive anode for future electrochemical energy storage systems.