Investigation and comparison of pristine/doped BN,AlN, and CN nanotubes as drug delivery systems for Tegafur drug: a theoretical study

Structural Chemistry - In this work, the potential of BN, AlN, and CN nanotubes as the drug delivery systems of Tegafur (TG) was investigated by the density functional theory (DFT). The doping...     

ZnBr2 catalyzed domino Knoevenagel-hetero-Diels–Alder reaction: An efficient route to polycyclic thiopyranoindol annulated [3,4-c]quinolone derivatives

Various novel polycyclic thiopyranoindol annulated [3,4-c]quinolone derivatives were synthesized via domino Knoevenagel-hetero-Diels–Alder reactions of indoline-2-thions and novel N-acrylated anthranilaldehydes in refluxing ethanol as a solvent in the presence of 20 mol% ZnBr₂ as a Lewis acid catalyst. All reactions proceed with high yields with excellent regio- and stereoselectivity.     

Synthesis and crystal structure of some 3,5-pyrazolidinediones

Syntheses of various derivatives of 3,5-pyrazolidenedione are reported. This includes 4-arylidene (alkylidene or aralkylidene)-3,5-pyrazolidinediones, which on epoxidation gave unreported oxiranes. The syntheses of these derivatives were based on either the Knoevenagel reaction of carbonyl derivatives with 3,4-pyrazolidinedione or cyclization of arylidene (alkylidene) malonic acid hydrazide with glacial acetic acid. 4-Arylazo-3,5-pyrazolidinedione derivatives were also prepared by coupling of aryldiazonium salts with 3,5-pyrazolidinedione or cyclization of arylazomalonic acid hydrazide. Reduction of 4-benzylidene derivatives gave the corresponding benzyl derivatives. The structure of the new products was confirmed by elemental and spectral analyses and X-ray crystallography.     

Complexity theory and collaboration: An agent-based simulator for a space mission design team

In this paper, we investigate how complexity theory can benefit collaboration by applying an agent-based computer simulation approach to a new form of synchronous real-time collaborative engineering design. Fieldwork was conducted with a space mission design team during their actual design sessions, to collect data on their group conversations, team interdependencies, and error monitoring and recovery practices. Based on the fieldwork analysis, an agent-based simulator was constructed. The simulation shows how error recovery and monitoring is affected by the number of small group, or sidebar, conversations, and consequent noise in the room environment. This simulation shows that it is possible to create a virtual environment with cooperating agents interacting in a dynamic environment. This simulation approach is useful for identifying the best scenarios and eliminating potential catastrophic combinations of parameters and values, where error recovery and workload in collaborative engineering design could be significantly impacted. This approach is also useful for defining strategies for integrating solutions into organizations. Narjès Bellamine-Ben Saoud is an Associate Professor at the University of Tunis and Researcher at RIADI-GDL Laboratory, Tunisia. After Computer Science engineering diploma (1993) of the ENSEEIHT of Toulouse, France, she received her PhD (1996), on groupware design applied to the study of cooperation within a space project, from the University of Toulouse I, France. Her main research interests concern studying complex systems particularly by modeling and simulating collaborative and socio-technical systems; developing Computer Supported Collaborative Learning in tunisian primary schools; and Software Engineering. Her current reserach projects include modeling and simulation of emergency rescue activities for large-scale accidents, modeling of epidemics and study of malaria, simulation of collabration artifacts. Gloria Mark is an Associate Professor in the Department of Informatics, University of California, Irvine. Dr. Mark received her Ph.D. in Psychology from Columbia University in 1991. Prior to UCI, she was a Research Scientist at the GMD, in Bonn, Germany, a visiting research scientist at the Boeing Company, and a research scientist at the Electronic Data Systems Center for Advanced Research. Dr. Mark’s research focuses on the design and evaluation of collaborative systems. Her current projects include studying worklife in the network-centric organization, multi-tasking of information workers, nomad workers, and a work in a large-scale medical collaboratory. Dr. Mark is widely published in the fields of CSCW and HCI, is currently the program co-chair for the ACM CSCW’06 conference and is on the editorial board of Computer Supported Cooperative Work: The Journal of Collaborative Computing, and e-Service Qu@rterly.     

Electrospun metal‐organic framework/polyacrylonitrile composite nanofibrous mat as a microsorbent for the extraction of tetracycline residue in human blood plasma

A new composite nanofiber of polyacrylonitrile doped with copper benzene‐1,3,5‐tricarboxylate metal‐organic framework was fabricated by electrospinning and used as a microsorbent in the solid‐phase extraction of trace tetracycline. The chemical structure of the adsorbent was studied by X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area analysis, and Barrett‐Joyner‐Halenda pore size and volume analysis techniques. The significant parameters of the method including desorption solvent kind and volume, adsorbent mass, pH, and salt percentage were investigated. At the optimized conditions, the linear range was 8–1000 μg/L with a determination coefficient (R²) of 0.9954. The limits of detection and quantification were 2.40 and 8.00 μg/L, respectively. The inter‐ and intraday precisions were 4.7 and 3.4%, respectively. The developed extraction method was followed by high‐performance liquid chromatography and applied for the determination of tetracycline in human blood plasma, and good relative recoveries (97.3‐104.5%) were obtained.     

Reactions of 4-alkylidene (arylidene)-1-phenylpyrazolidine-3,5-dione

Reactions of 4-alkylidene(arylidene)-1-phenylpyrazolidine-3,5-dione with oxidizing (chromium trioxide/acetic acid) as well as with reducing (sodium borohydride/methanol) agents were carried out. Phenylhydrazine reacted with 4-arylidene-1-phenylpyrazolidine-3,5-diones via fission of exo C=C bond to give 1-phenylpyrazolidine-3,5-dione and the corresponding aryl hydrazones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1335–1341, September, 2007.     

Redox isomerisation of allylic alcohols catalysed by water-soluble ruthenium complexes in aqueous systems

The process of catalytic isomerisation of various allylic alcohols (alk-1-en-3-ols) into saturated ketones under mild conditions is reported. The water-soluble Na₄[{RuCl₂(mtppms)₂}₂] complex, previously reported by us as a precursor to very active hydrogenation catalysts was also found an active catalyst of the redox isomerisation of allylic alcohols in aqueous media. The new Na[Ru(CO)Cp(mtppms)₂] as well as Na₄[{RuCl(μ-Cl)(CCCPh₂)(mtppms)₂}₂] and Na₂[RuClCp(mtppms)₂] also showed good to excellent catalytic activities for redox isomerisations in aqueous systems at 50-80 °C under inert atmosphere.