bluuebunny/crossref_metadata_2025 huggingface dataset:
Information Fusion Embrittlement Models for U.S. Power Reactor Pressure Vessel Steels
Authors: Wang J. A. , Rao N. S. V. , Konduri S.
Published: August 2007

A new approach of utilizing information fusion technique is developed to predict the radiation embrittlement of reactor pressure vessel steels. The Charpy transition temperature shift data contained in the Power Reactor Embrittlement Database is used in this study. Six parameters—Cu, Ni, P, neutron fluence, irradiation time, and irradiation temperature—are used in the embrittlement prediction models. The results indicate that this new embrittlement predictor achieved reductions of about 49.5 % and 52 % in the uncertainties for plate and weld data, respectively, for pressurized water reactor and boiling water reactor data, compared with the Nuclear Regulatory Commission Regulatory Guide 1.99, Rev. 2. The implications of dose-rate effect and irradiation temperature effects for the development of radiation embrittlement models are also discussed.
Sustainability in Building Construction—International Standards in Progress
Authors: Trinius Wolfram , Sjöström Christer
Published: August 2007

The development of ISO 15392 on general principles of sustainability in building construction took more time than expected. The most significant reason for this was the need to identify a common basis for the conceptual content of the document. With this basis now being identified, the work has taken up momentum and the general principles document presents principles to be considered when addressing the thematic field of sustainable development in relation to building and civil engineering. A key problem to be tackled in international standardization is finding the balance between the necessary level of detail to actually provide something to the user of the standard, and at the same time not to be too specific in order to allow different nations and their specific perspectives to still agree to the standard. While the challenge of sustainable development is global, the strategies for addressing sustainability in building construction are local and differ in context and content from region to region. Such strategies will reflect the context not only in the building environment, but also very much the social environment. This social environment includes cultural issues, legislation and regulation, as well as the needs and concerns of all the users and interested parties involved. Applying the concept of sustainability to specific buildings or other construction works includes a holistic approach, bringing together the global concerns and goals of sustainable development and the demands and requirements in terms of product functionality, efficiency, and economy. Different target audiences will have a different perspective on these challenges and the preferred solutions. The standards must hence put the topic onto a common playing field, still allowing different perspectives to be applied and priorities to be set, as well as recognizing that many aspects of sustainable development lie without the possible content of international technical standardization. ISO 15392 is related to and set into the context of other international standards and widely applied concepts, such as the performance-based building concept and the ISO 15686 series. This paper illustrates the set of related international standards and discusses the modular application. We want to discuss key factors needing consideration in order to bring the set of standards to successful application.
Pressure Effects on Oxygen Concentration Flammability Thresholds of Polymeric Materials for Aerospace Applications
Authors: Hirsch David , Williams Jim , Beeson Harold
Published: August 2007

Spacecraft materials selection is based on an upward flammability test conducted in a quiescent environment at the highest expected oxygen concentration. However, NASA’s advanced space exploration program is anticipating using various habitable environments. Because limited data are available to support current program requirements, a different test logic is suggested to address the expanded atmospheric environments through the determination of materials self-extinguishment limits. This paper provides additional pressure effects data on oxygen concentration and partial pressure self-extinguishment limits under quiescent conditions. For the range of total pressures tested, the oxygen concentration and oxygen partial pressure flammability thresholds show a near linear dependence on total pressure, and appear to increase with increasing oxygen concentration (and oxygen partial pressure) thresholds. For the Constellation Program, the flammability threshold information will allow NASA to identify materials with increased flammability risk from oxygen concentration and total pressure changes, minimize potential impacts, and allow for development of sound requirements for new spacecraft and extraterrestrial landers and habitats.
Mobile Agenten für den Fernzugriff auf eingebettete Systeme (Mobile Agents for Remote Access to Embedded Systems)
Authors: Renner Josef , Protzel Peter
Published: August 2007

In der Automatisierungstechnik sind Fernzugriffe auf Geräte und Anlagen bereits heute eine wesentliche Anwendung der Teleautomation. Zum Einsatz kommen dabei Teleservice-Systeme unter Nutzung analoger und digitaler Wählleitungen oder Internet-Verbindungen. Mobile Agenten können zukünftig die Technologie der Fernzugriffe innerhalb der Automatisierungstechnik deutlich verbessern. Ein sehr großer Teil der Automatisierungsgeräte und Systeme ist dem Bereich der eingebetteten Systeme zuzurechnen. Diese Systeme benötigen zur “Agenten-Fähigkeit” eine Netzwerkanbindung und eine integrierte Agenten-Plattform. Dieser Artikel beschreibt die dazu erforderlichen Anpassungen und erläutert vier mögliche Anwendungsszenarien eines Fernzugriff-Agenten für die Automatisierungstechnik.
Sinnvolle sozio-ökonomische Weiterentwicklung der globalisierten Gesellschaft (Sustainable Further Socio-economic Evolution of the Globalized Society)
Authors: Welfonder Ernst
Published: August 2007

Ausgehend von der immer schnelleren technisch-wirtschaftlichen Entwicklung werden die Hintergründe dieser Eigendynamik sowie die resultierenden Auswirkungen bezüglich der ständigen Zunahme von Ressourcenverbrauch und Umweltbelastung sowie der Bevölkerungsentwicklung aufgezeigt.

Die bestehenden interdisziplinären Zusammenhänge werden anhand analytischer Betrachtungen, statistischer Zeitreihen und simulationstechnischer Untersuchungen erläutert. Dabei kommt der Rückwirkung der Automatisierung auf die Gesellschaft besondere Bedeutung zu. Darauf aufbauend werden notwendige Gegenmaßnahmen zur Ermöglichung einer nachhaltigen Weiterentwicklung der globalisierten Gesellschaft hergeleitet.

Diese Aussagen decken sich in wesentlichen Punkten mit den Zielsetzungen der Global Marshallplan Initiative.
Thirteen‐week Inhalation Toxicity of Carbon Tetrachloride in Rats and Mice
Authors: Nagano Kasuke , Umeda Yumi , Saito Misae , Nishizawa Tomoshi , Ikawa Naoki , Arito Heihachiro , Yamamoto Seigo , Fukushima Shoji
Published: August 2007

Thirteen‐week Inhalation Toxicity of Carbon Tetrachloride in Rats and Mice: Kasuke Nagano, et al. Japan Bioassay Research Center, Japan Industrial Safety and Health Association—Subchronic toxicity of carbon tetrachloride (CCl4) was examined by inhalation exposure of F344 rats and BDF1 mice of both sexes to 0, 10, 30, 90, 270 or 810 ppm (v/ v) CCl4 vapor for 13 wk (6 h/d and 5 d/wk). In the high exposure levels at 270 and 810 ppm, altered cell foci in the livers of both rats and mice, and fibrosis and cirrhosis in the rat liver were observed. Hematoxylin and eosin‐stained altered cell foci of rats were recognized as glutathione‐S‐transferase placental form (GST‐P) positive foci, which are preneoplastic lesions of hepatocarcinogenesis. The most sensitive endpoint of CCl4‐induced toxicity was fatty change with large droplets in rats of both sexes and male mice, and cytoplasmic globules in male mice, as well as increased relative liver weight in male rats. Those endpoints were manifested at 10 ppm and the LOAEL was determined as 10 ppm for the hepatic endpoints in rats and mice. Enhanced cytolytic release of liver transaminases into plasma in rats and mice and its close association with hepatic collapse in mice were observed at medium and high levels of inhalation exposure. Both CCl4‐induced hematotoxicity and nephrotoxicity were observed in both rats and mice, but those toxicities were manifested at higher exposure concentrations than hepatotoxicity. The LOAEL for the hepatic endpoint and the GST‐P‐stained altered cell foci provide relevant animal data for reconsidering the occupational exposure limit value of 5 ppm for CCl4 and strengthen the evidence of CCl4induced hepatocarcinogenicity which is used in its carcinogenicity classification.
Detection of Mutant p53 Protein in Workers Occupationally Exposed to Benzidine
Authors: Xiang Cui‐Qin , Shen Chun‐Lin , Wu Zi‐Rong , Qin Yi‐Qiu , Zhang Yun‐Ying , Liu Cha‐Zhen , Chen Ji‐Gang , Zhang Sheng‐Nian
Published: August 2007

Detection of Mutant p53 Protein in Workers Occupationally Exposed to Benzidine: Cui‐Qin Xiang, et al. Shanghai Municipal Center for Disease Control & Prevention, China—To investigate the expression of mutant p53 protein in workers occupationally exposed to benzidine, we detected mutant p53 protein by immuno‐PCR assay in the serum of 331 benzidine‐exposed healthy workers, while we classified exfoliated urothelial cells in urine samples with Papanicoloau's grading (PG). The Papanicoloau's grading classified exfoliated urothelial cells of the subjects from grade I (normal cells) to grade III (suspicious malignant cells). The subjects were also divided into high, medium and low exposure groups according to the exposure intensity index. The results revealed that mutant p53 protein in the medium and high exposure groups were significantly higher than the in low exposure group (p<0.05), and in PG II and III were significantly higher than in the PG I (p<0.05). There was no significant differences among Papanicoloau's gradings strata in the low exposure group on the incidence and quantity of mutant p53 protein. In the medium and high exposure groups, the incidence and/or quantity of mutant p53 protein in the stratum of PG II and/or III were significantly higher than that of PG I (p<0.05). Detection of mutant p53 protein in conjunction with benzidine exposure level and Papanicoloau's gradings of exfoliated urothelial cells could provide more information to help us elevate surveillance efficiency and diagnose bladder cancer in the early period.
Evaluation of Zebrafish Danio rerio as a Model for Enteric Septicemia of Catfish (ESC)
Authors: Petrie-Hanson L. , Romano C. L. , Mackey R. B. , Khosravi P. , Hohn C. M. , Boyle C. R.
Published: August 2007

Zebrafish (also known as zebra danio) Danio rerio were injected intramuscularly with Edwardsiella ictaluri at doses of 6 × 103, 6 × 104, or 6 × 105 colony-forming units per gram (CFU/g) or sterile phosphate-buffered saline (sham) or were not injected. Mortality occurred from 2 to 5 d postinjection (dpi) at rates of 0, 76.6, and 81.3% for the low, medium, and high doses, respectively, and E. ictaluri was isolated from dead fish. Survivors were sampled at 10 dpi and E. ictaluri was not isolated. Sham-injected and noninjected controls did not suffer mortality. Histopathology trials were performed in which zebrafish were injected with 1 × 104 CFU/g or sham-injected and sampled at 12, 24, 48, 72, and 96 h postinjection for histological interpretation. Collectively, these zebrafish demonstrated increasing severity of splenic, hepatic, cardiac, and renal interstitial necrosis over time. To evaluate the progression of chronic infection, zebrafish were injected with 1 × 102 CFU/g and held for 1 month postinjection. Beginning at 12 dpi and continuing for an additional 2 weeks, zebrafish demonstrated abnormal spiraling and circling swimming behaviors. Histopathology demonstrated necrotizing encephalitis. In immersion trials, zebrafish were exposed to low, medium, and high doses (averaging 1.16 × 105, 1.16 × 106, and 1.16 × 107 CFU/mL of tank water) of E. ictaluri for 2 h. Mortality occurred from 5 to 9 d postexposure at rates of 0, 3.3, and 13.3% for the low, medium, and high doses, respectively; E. ictaluri was isolated from dead fish. Channel catfish Ictalurus punctatus exposed to the medium doses suffered 100% mortality, and E. ictaluri was isolated from these fish. This study demonstrates the potential use of zebrafish as a model for E. ictaluri pathogenesis.
Isolation of thymus gland fractions and the determination of their biological activity
Authors: Radeta Milena , Novakovic Jasna , Vico-Stevanovic Milanka , Simic Slobodanka , Pirozkov Aleksandar
Published: August 2007

A calf thymus extract was prepared and fractionated into lipid and non-lipid fractions. The non-lipid fraction was isolated from the calf thymus extract using the Folch method. The components isolated from the non-lipid fraction were characterized by IR, NMR, biuret and HPLC method. The results of the analyses indicated the presence of peptides. The lipid fraction contained phospholipids, glycolipids and neutral lipids. The biological activity of both the isolated lipid and peptide fractions was determined by the in vivo hemolytic plaques method in Wistar rats with an involuted thymus. The peptide and phospholipid fractions of the thymus extract showed a significant increase of hemolytic plaques. The glycolipid and neutral lipid fraction failed to express a significant immunological response.
A marginal contribution of selected carotenoids to the supression of UV-irradiation-induced lecithin peroxidation in hexane solution
Authors: Cvetkovic Dragan , Markovic Dejan
Published: August 2007

The aim of this work was to study the anticipated antioxidant role of four selected carotenoids in mixtures with lecithin lipoidal compounds in hexane solution, under continuous UV-irradiation in three different ranges (UV-A, UV-B and UV-C). Two carotenes (b-carotene and licopene) and two xantophylls (lutein and neoxanthin) were employed to control the lipid peroxidation process generated by UV-irradiation, by scavenging the involved free radicals. The results show that while carotenoids undergo a substantial, structural dependent destruction (bleaching), which is highly dependent on energy of the UV-photons, their contribution to the expected suppression of lecithin peroxidation is of marginal importance, not exceeding a maximum of 20%. The marginal antioxidant behaviour has been attributed to a highly unordered hexane solution, where the scavenging action of the carotenoids becomes less competitive.
The template synthesis, spectral characterization and thermal behavior of new binuclear Schiff base complexes derived from N-aminopyrimidine with 2,3-butandion
Authors: Sönmez Mehmet , Şekerci Memet
Published: August 2007

Anew series of two types of acyclic binuclear Schiff base complexes, prepared by the template condensation of N-aminopyrimidine and 2,3-butandion in the presence of Cu(II), Ni(II), Co(II) and Zn(II) in n-BuOH solution, were analyzed and characterized by elemental analyses, IR and electronic spectroscopy, conductivity and magnetic measurements. From the conductivity measurements, it is concluded that the complex of NiII is a 1:1 type of electrolyte. All the complexes have sub-normal magnetic moments in accordance with their binuclear nature. The thermal behaviour of the complexes was studied by thermogravimetry.
Electronic structure of planar-quasicycled organic molecules with intramolecular hydrogen bond
Authors: Pankratov Alexei , Shalabay Alexei
Published: August 2007

By means of the HF/6-311G(d,p) method, the electronic structure of the series of organic molecules, among which are malonaldehyde, acetylacetone, thiomalonaldehyde,?the derivatives of aniline 2-XC6H4NH2, phenol 2-XC6H4OH, benzenethiol 2-XC6H4SH (X = CHO, COOH, COO-, NO, NO2, OH, OCH3, SH, SCH3, F, Cl, Br), 8-hydroxyquinoline, 8-mercaptoquinoline, tropolone, has been studied. The intramolecular hydrogen bond (IHB) has been established to lead to a local electron redistribution in quasicycle, and primarily to the electron density transfer between the direct IHB participants - from the hydrogen atom toward the proton-aceptor atom. On forming the IHB of the S-H???O type, the electron density in general decreases on the sulphohydryl hydrogen atom and increases on the sulphur atom.
Cytotoxic and antimicrobial activities of two new synthetic 2'-oxygenated flavones reported from andrographis viscosula
Authors: Mostahar Sohel , Alam Sayed , Islam Azizul
Published: August 2007

Two new 2'-oxygenated flavones have been synthesized via chalcone precursors and the biocidal activity of these two flavones, along with the corresponding chalcones against microbes (bacteria and fungi) and brine shrimp nauplii were investigated. Both the flavones (compounds 6 and 7) and their corresponding chalcones (compounds 4 and 5) showed good activity against all the tested bacterial and fungal strains. The LC50 values of compounds 4-7 were found to be 2.31, 0.94, 1.39 and 0.58 ?gmL -1, respectively. The synthesized compounds were characterized using UV-Vis, IR, 1H-NMR and 13C-NMR spectral data, together with elemental analysis. .
Determination of nitrate by the IE-HPLC-UV method in the brain tissues of Wistar rats poisoned with paraquat
Authors: Curcic-Jovanovic Marijana , Djukic Mirjana , Vasiljevic Ivana , Ninkovic Milica , Jovanovic Marina
Published: August 2007

This work was a part of an initial study regarding the involvement of reactive nitrogen species (RNS) in paraquat (PQ) neurotoxicity. The nitrate concentration in the vulnerable regions of the brain (cortex, striatum and hippocampus) of Wistar rats was used as a measure of nitric oxide (NO) production or catabolism of the formed RNS. The tissue homogenates were deproteinized with acetonitrile and then centrifuged. Nitrate was measured in filtrated supernatants by simple and rapid isocratic ion-exchange high performance liquid chromatography with UV detection (IE-HPLC-UV) at 214 nm. The mobile phase (pH 8.5) consisted of borate buffer/gluconate concentrate, methanol, acetonitrile and deionized water (2:12:12:74, v/v/v/v), and the flow rate was 1.3 mL/min. Physiological nitrate levels (18.8 ? 6.1 nmol/mg of proteins), as well as a diverse range of nitrate concentrations could be determined with good precision (CV = 2.2 %) and accuracy (recovery of spiked samples was 99 ? 4%) in the brain tissue homogenates. Linearity was achieved in the range of nitrate from 0-80 ?M. The retention time of nitrate anion was 5.3 ? 0.3 min. .
Asymmetric Meerwein-Ponndorf-Verley reduction of long chain keto alkanoic acid methyl esters
Authors: Onar Çelik , Hasdemir Belma , Yusufoğlu Ayse
Published: August 2007

3-, 7- and 13-Monoketo tetradecanoic acid methyl esters carrying a keto group at the ends and at the middle of the chain with 14 carbon atoms were reduced by a Meerwein-Ponndorf-Verley reaction in the presence of R-(+)-1,1'-binaphthalene- 2,2'-diol, 1,2:5,6-D-di-O-isopropylidene-D-mannitol and L-(-)-menthol. The highest enantiomeric purity of 65% ee was found for 13-hydroxy ester isomer. The enantiomeric excess was determined by 1H-NMR shift with Eu(tfc)3 and by optical rotation.
Volumetric, viscometric and refractive index behavior of amino acids in aqueous glycerol at different temperatures
Authors: Ali A. , Khan S. , Nabi F.
Published: August 2007

Densities, ?, viscosities, ? and refractive indices, n D, of solutions of some amino acids (glycine, DL-alanine, DL-? -amino- n-butyric acid, L-valine and L-leucine) in the concentration range 0.02 to 0.10 m in 5 % (v/v) aqueous glycerol were determined at 298.15, 303.15, 308.15 and 313.15 K. These experimental data were used to calculate the apparent molar volumes, ? v, the infinite dilution apparent molar volumes, ? v 0, the partial molar volumes of transfer, ? v 0 (tr), of the amino acids from aqueous to aqueous glycerol solution, as well as the viscosity A and B coefficients of the Jones-Dole equation of the amino acids. The free energies of activation of viscous flow, ??1 0# and ?? 2 0# per mole of solvent and solute, respectively, were obtained by application of the transition-state theory to the B coefficient data and the corresponding activation enthalpy, ?H*, and entropy, ?S*, were also determined. The ? v 0, B coefficients and ?? 2 0# were found to vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids, and they were split into contributions from the zwitterionic end groups (NH3 +, COO-) and methylene (CH2) groups of the amino acids. The experimental values of the refractive indices, n D, were used to calculate the molar refractive indices, R D, of the amino acids + aqueous glycerol ternary mixtures. The results were interpreted in the light of the solute-solvent and solute-solute interactions in the mixed solvents.
Low temperature crystal structure, experimental atomic charges and electrostatic potential of ammonium decavanadate hexahydrate (NH4)V10O28·6H2O
Authors: Bogdanovic Goran , Bosnjakovic-Pavlovic Nada , Spasojevic-De Bire , Ghermanic Eddine , Mioc Ubavka
Published: August 2007

The X-ray structure of ammonium decavanadate hexahydrate was redetermined at a low temperature (100 K) in order to locate the hydrogen sites and to study the hydrogen bonds. The hydrogen atoms were assigned to the appropriate atomic group, NH4 + cations, and water molecules, missing to the best of our knowledge in the literature. A kappa refinement was performed to estimate the experimental atomic charges. These charges were used to generale the electrostatic potential on the molecular surfaces of decavanadate polyanions isolated from the influence of the crystal lattice. Comparisons with previous theoretical (ab initio) calculations were made and are also discussed. .
Hydration study of mechanically activated mixtures of Portland cement and fly ash
Authors: Stefanovic Gordana , Cojbasic Ljubica , Sekulic Zivko , Matijasevic Srdjan
Published: August 2007

Fly ash (FA) can be used in cement mixtures with certain limitations. The problem of the mentioned mixtures lies in the insufficient activity of the particles of FA in the reactions which are important for the establishment of the mechanical characteristics of cement. This is particularly true for the hydration reactions. As a result of this, cement pastes formed by mixing ash and clinker have worse characteristics compared to those of pure Portland cement (PC), especially in the early period of setting. As is well known, FA can be a good solution for the neutralization of the negative effects generated due to the creation of free Ca(OH)2 during the hydration of PC, provided that the problems with the low activity of FAare overcome. For the experiments in this study, a mixture of Portland cement and fly ash was used, the content of ash in the mixture being 30 % and 50 %. Mechanical activation was performed in a vibrating ring mill. The goal of this study was to demonstrate, through experimental results, that during the mechanical activation of a PC and FA mixture, the components in the mixture which mostly affect the direction, rate and range of hydration reactions occurring in the mixture had been activated. The values of the compressive strength of the activated and non-activated mixtures and the changes of their specific surface area proved that during the grinding process, the mixture PC+FA had been mechanically activated. The highest increase of compressive strength was achieved in the early period of setting, which indicates an improvement in the early hydration of the mixture. XRD, DTA and TG analyses showed that the alite (C3S) and belite (C2S) from the PC and a part of the fly ash were activated. .
Removal of metal cations from wastewater using recycled wool-based non-woven material
Authors: Radetic Maja , Radojevic Darinka , Ilic Vesna , Jocic Dragan , Povrenovic Dragan , Potkonjak Branislav , Puac Nevena , Jovancic Petar
Published: August 2007

In this study, the effect of low-temperature air plasma, biopolymer chitosan and hydrogen peroxide treatment of recycled wool-based non-woven material on metal cation uptake was investigated. Recycled wool-based material either as an untreated or modified material showed ability to bind all investigated metal cations in the following order: Pb2+>Cu2+>Zn2+>Co2+. Material performed good selectivity due to distinct sorption rates of studied metal cations. .
Location of the hydrophobic pocket in the binding site of fentanyl analogs in the µ-opioid receptor
Authors: Dosen-Micovic Ljiljana , Ivanovic Milovan , Micovic Vuk
Published: August 2007

Fentanyl is a highly potent and clinically widely used narcotic analgesic. The synthesis of its analogs remains a challenge in an attempt to develop highly selective ?-opioid receptor agonists with specific pharmacological properties. In this paper, the use of flexible molecular docking of several specific fentanyl analogs to the ?-opioid receptor model, in order to test the hypothesis that the hydrophobic pocket accommodates alkyl groups at position 3 of the fentanyl skeleton, is described. The stereoisomers of the following compounds were studied: cis- and trans-3-methylfentanyl, 3,3-dimethylfentanyl, cis- and trans-3-ethylfentanyl, cis- and trans-3-propylfentanyl, cis-3-isopropylfentanyl and cis-3-benzylfentanyl. The optimal position and orientation of these fentanyl analogs in the binding pocket of the ?-receptor, explaining their enantiospecific potency, were determined. It was found that the 3-alkyl group of cis-3R,4S and trans-3S,4S stereoisomers of all the active compounds occupies the hydrophobic pocket between TM5, TM6 and TM7, made up of the amino acids Trp318 (TM7), Ile322 (TM7), Ile301 (TM6) and Phe237 (TM5). However, the fact that this hydrophobic pocket can also accommodate the bulky 3-alkyl substituents of the two inactive compounds: cis-3-isopropylfentanyl, and cis-3-benzylfentanyl, indicates that this hydrophobic pocket in the employed receptor model is probably too large. .
Relating resonance energy with the Zhang-Zhang polynomial
Authors: Gojak Sabina , Gutman Ivan , Radenkovic Slavko , Vodopivec Andrej
Published: August 2007

The Zhang-Zhang polynomial ?(x) is a recently conceived tool in the mathematical apparatus of theoretical chemistry. It combines (in a quantitative manner) the Kekul?- and Clar-structure-based features of benzenoid molecules. It is shown that the topological resonance energy (TRE) can be accurately approximated as TRE ? a??(x)+ b where x?0.5, by which fact a significant insight is gained into the structure-dependence of TRE of benzenoid molecules.
Oxygen reduction at platinum nanoparticles supported on carbon cryogel in alkaline solution
Authors: Elezovic N.R. , Babic B.M. , Vracar LJ.M. , Krstajic N.V.
Published: August 2007

The oxygen reduction reaction was investigated in 0.1 M NaOH solution, on a porous coated electrode formed of Pt particles supported on carbon cryogel. The Pt/C catalyst was characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry techniques. The results demonstrated a successful reduction of Pt to metallic form and homogenous Pt particle size distribution with a mean particle size of about 2.7 nm. The ORR kinetics was investigated by linear sweep polarization at a rotating disc electrode. The results showed the existence of two E - log j regions, usually referred to polycrystalline Pt in acid and alkaline solution. At low current densities (lcd), the Tafel slope was found to be close to -2.3RT/F, while at high current densities (hcd) it was found to be close to -2?2.3RT/F. It is proposed that the main path in the ORR mechanism on Pt particles was the direct four-electron process, with the transfer of the first electron as the rate determining step. If the activities are expressed through the specific current densities, a small enhancement of the catalytic activity for Pt/C was observed compared to that of polycrystalline Pt. The effect of the Pt particle size on the electrocatalysis of oxygen reduction was ascribed to the predominant (111) facets of the platinum crystallites. .
Thermo-oxidative stability of waterborne polyurethanes with catalysts of different selectivity evaluated by non-isothermal thermogravimetry
Authors: Cakic Suzana , Nikolic Goran , Stamenkovic Jakov
Published: August 2007

Thermogravimetry was used for the evaluation of the thermo-oxidative stability of waterborne polyurethanes (wbPUR) containing catalysts of different selectivity. From Arrhenius plots, activation energies of between 50 and 120 kJ mol-1 for wbPUR were determined, depending on the temperature interval, selectivity of the catalyst and degree of degradation. Waterborne polyurethanes without catalyst showed lower thermal stability than waterborne polyurethanes with catalysts of different selectivity. Non-isothermal thermogravimetry indicated the presence of different degradation processes and enabled the kinetics parameters at higher degrees of degradation to be evaluated. .
Basic and mixed models for computer simulation of liquid phase sintering of a porous structure
Authors: Nikolic Z.S.
Published: August 2007

A two-dimensional method based on basic and mixed models for simulation of liquid phase sintering of a porous structure will be developed. These models will be tested in order to conduct a study of diffusion phenomena and gravitational effects on microstructural evolution during liquid phase sintering of a W-Ni system.
Study on densification of laser ignited reaction sintering of Ni-Al-Cu powder
Authors: Liu Y.H. , Guo Z.X. , Shen P. , Wang H.Y. , Hu J.D.
Published: August 2007

The mechanisms of densification during laser ignited reaction sintering of Ni-Al-Cu powder materials were studied. With the addition of Cu, densification of Ni-Al-Cu specimens made of big particles was realized under laser rapid ignition and sintering without signification change of the final products. Filling of the mixture of liquid and disintegrated small grains or particles was regarded as the dominant mechanism for the final densification.
Influence of mechanical activation on synthesis and properties of the MgO-TiO2 system
Authors: Petrovic Vera , Maricic A. , Labus N. , Ristic M.M.
Published: August 2007

Materials applied in electronics such as multilayer capacitors are an important field of ceramic materials. Magnesium titanate based dielectric materials are used for producing type-I capacitors. A common way of obtaining this material is a solid-state reaction during reaction sintering. The process of sintering can be enhanced if mechanical activation precedes. In this work starting powders of magnesium carbonate (MgCO3) and titanium dioxide (TiO2) with a rutile crystal modification were weighed to attain a 1:1 molar MgCO3:TiO2 ratio. Mechanical activation of the starting mixture was performed by high energy ball milling using ZrO balls and vessels with a ball to powder mass ratio of 40:1. The observed grinding times were 15, 30, 60 and 120 minutes. Powder characterization was conducted using X ray powder diffraction, DTA analysis up to 1000 o C and particle morphology changes were observed with Scanning Electron Microscopy. Isothermal sintering of compacted powders was conducted at 1100?C during 30, 60 and 180 minutes. For specimens synthesized in such a manner, microwave dielectric properties were measured, quality factor Q, specific electrical resistivity (?) and the dielectric constant (?r). In this work we explain the influence of mechanical activation on the MgCO3-TiO2 system leading to titanate formation during sintering, as well as induced changes in microwave dielectric properties.
Introduction
Authors: Jansen Stef , Löfving Staffan
Published: August 2007

By giving an extensive literature review and presenting the central objectives of this theme section, this introductory article develops a programmatic call for a critical anthropology of 'home' in relation to violence and place. Challenging assumptions that territoriality, rootedness, and memories of violence are necessarily the primary determinants of identification among people on the move, it proposes conceptual tools to investigate how and when such discourses may provide or prohibit the making of 'home'. In particular, it draws attention to issues of political and economic transformation and the changing forms of violence and movement produced by them.
Indigenous resurgence, anthropological theory, and the cunning of history
Authors: Turner Terence
Published: August 2007

Why has the recent period of global centralization of capital, from the 1970s to the present, also been a period of resurgence of indigenous movements and of forms of global civil society that have supported indigenous rights? This article argues that tackling this question can only be done by using concepts that emphasize what Hegel called the 'cunning' of history: the fact that the same historical process can on the one hand bring devastation to indigenous habitats and on the other hand create opportunities for political leverage by indigenous societies to gain recognition of the legitimacy of their different social, cultural, and economic systems within their ambient nation-states. Politically engaged anthropological theory, it seems, needs concepts that emphasize these contradictions—which in a nutshell means more Marx and less Foucault.
In vitro Release Kinetics Study of Diclofenac Sodium from Acrylic Polymer Coated Pellets
Authors: Kibria Golam , Jalil Reza-ul
Published: August 2007

The aim of the present study is to investigate the effect of Ammonio Methacrylate Copolymer Type B (Eudragit RS 30 D) on the release kinetics study of diclofenac sodium form coated pellets. The effect of the incorporation of xanthan gum into the coating formulation was also the goal of this study. Eudragit RS 30 D and xanthan gum was added into the formulation at 5:1 ratio. Different percent of this polymeric combination was loaded on to the drug-loaded pellets. It was found that the cumulative % release of drug decreased with the increase of polymer load in all cases. From all formulations it was observed that the release of diclofenac sodium in 0.1N HCl media was very low (maximum 3.5%) at first 2 hours. Better sustaining effect was found from Eudragit RS 30 D and xanthan gum combinations. Drug was released linearly along with time throughout the whole dissolution process in phosphate buffer (pH 6.8) and it was also revealed that, in all cases the release of diclofenac sodium followed mixed release kinetics but zero order release kinetics predominates.

Key words: Diclofenac sodium, pellets, sustained release, in vitro, kinetic analysis.

Dhaka Univ. J. Pharm. Sci. 6(1): 1-7, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
Novel Floating Pulsatile Approach for Chronotherapeutic Release of Indomethacin
Authors: Jessy Shaji , Vishal Patole
Published: August 2007

The main objective of the present study was to develop a multiple-unit, floating-pulsatile drug delivery system for obtaining no drug release during floating and in the proximal small intestine followed by pulsed, rapid drug release in distal small intestine to achieve chronotherapeutic release of indomethacin. The system developed consists of drug containing core pellets prepared by extrusion-spheronization process, which were coated with an inner pH-dependent layer of Eudragit S100 and outer effervescent layer of sodium bicarbonate and HPMC K100M. Pellets showed instantaneous floating with no drug release in acidic medium followed by pulsed drug release in basic medium. Concentration of HPMC K100M and layering level of effervescent agent significantly affected performance of pellets. The system showed excellent lag phase followed by burst release in the distal small intestine which gives site and time specific delivery of indomethacin acting as per chronotherapy of rheumatoid arthritis.

Key words: Floating-pulsatile drug delivery, Chronotherapeutic release, Indomethacin, Pellets, Rheumatoid arthritis.

Dhaka Univ. J. Pharm. Sci. 6(1): 37-41, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
Central Nervous System Depressant Activity of Wedelia trilobata Leaves
Authors: Tambe VD , Nirmal SA , Jadhav RS
Published: August 2007

Dhaka Univ. J. Pharm. Sci. 6(1): 59-60, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
Preliminary Antimicrobial Activity and Cytotoxicity of Brunfelsia latifolia
Authors: Begum Rokeya , Rahman Mohammad S , Chowdhury AM Sarwaruddin , Rashid Mohammad A
Published: August 2007

Dhaka Univ. J. Pharm. Sci. 6(1): 65-67, 2007 (June)

The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website
A novel discrete‐time sliding mode technique and its application to a HDD dual‐stage track‐seek and track‐following servo system
Authors: Herrmann G. , Edwards C. , Hredzak B. , Venkataramanan V. , Spurgeon S. K.
Published: August 2007

A novel approach for the design of a discrete‐time sliding mode controller is presented showing that the dynamics of a sliding‐mode state‐feedback controller can be designed using a singular LQR approach. The weighting of the control signal is set to zero and dead‐beat behaviour for the sliding mode reaching dynamics is achieved. The reaching dynamics are modified when the states are a significant distance away from the sliding surface to avoid any high magnitude control action due to the partial dead‐beat approach. The control law also takes into account the constraints on the actuator amplitudes and a stability analysis is presented using a discrete‐time version of the Popov criterion.

The control approach is demonstrated in conjunction with a recently developed large‐span track‐seeking and track‐following method for dual‐stage actuator systems in a hard disk drive (HDD). It is shown how the discrete‐time sliding mode control scheme can be incorporated into the observer‐based control system for the secondary actuator. Superior performance for the track‐seeking and track‐settling process is demonstrated using an existing practical set‐up of a dual‐stage HDD servo system. Copyright © 2007 John Wiley & Sons, Ltd.
Multifunctional Micelles for Cancer Cell Targeting, Distribution Imaging, and Anticancer Drug Delivery
Authors: Huang C.‐K. , Lo C.‐L. , Chen H.‐H. , Hsiue G.‐H.
Published: August 2007

Multifunctional micelles for cancer cell targeting, distribution imaging, and anticancer drug delivery were prepared from an environmentally‐sensitive graft copolymer, poly(N‐isopropyl acrylamide‐co‐methacryl acid)‐g‐poly(D,L‐lactide) (P(NIPAAm‐co‐MAAc)‐g‐PLA), a diblock copolymer, methoxy poly(ethylene glycol)‐b‐poly(D,L‐lactide) (mPEG‐PLA) and two functionalized diblock copolymers, galactosamine‐PEG‐PLA (Gal‐PEG‐PLA) and fluorescein isothiocyanate‐PEG‐PLA (FITC‐PEG‐PLA). Anticancer drug, free base doxorubicin (Dox) was incorporated into the inner core of multifunctional micelles by dialysis. From the drug release study, a change in pH (from pH 7.4 to 5.0) deformed the structure of the inner core from that of aggregated P(NIPAAm‐co‐MAAc), causing the release of a significant quantity of doxorubicin (Dox) from multifunctional micelles. Multifunctional micelles target specific tumors by an asialoglycoprotein (HepG2 cells)‐Gal (multifunctional micelle) receptor‐mediated tumor targeting mechanism. This mechanism then causes intracellular pH changes which induce Dox release from multifunctional micelles and that micelles have strong effects on the viability of HepG2 cells and are abolished by galactose. Confocal laser scanning microscopy (CLSM) reveals a clear distribution of multifunctional micelles. With careful design and sophisticated manipulation, polymeric micelles can be widely used in cancer diagnosis, cancer targeting, and cancer therapy simultaneously.
Novel Digital Nonvolatile Memory Devices Based on Semiconducting Polymer Thin Films
Authors: Baek S. , Lee D. , Kim J. , Hong S.‐H. , Kim O. , Ree M.
Published: August 2007

Recent increases in the demand for mobile devices have stimulated the development of nonvolatile memory devices with high performance. In this Communication, we describe the fabrication of low‐cost, high‐performance, digital nonvolatile memory devices based on semiconducting polymers, poly(o‐anthranilic acid) and poly(o‐anthranilic acid‐co‐aniline). These memory devices have ground‐breaking and novel current–voltage switching characteristics. The devices are switchable in a very low voltage range (which is much less than those of all other devices reported so far) with a very high ON/OFF current ratio (which is on the order of 105). The low critical voltages have the advantage for nonvolatile memory device applications of low operation voltages and hence low power consumption. With this very low power consumption, the devices demonstrate in air ambient to have very stable ON‐ and OFF‐states without any degradation for a very long time (which has been confirmed up to one year so far) and to be repeatedly written, read and erased. Our study proposes that the ON/OFF switching of the devices is mainly governed by a filament mechanism. The high ON/OFF switching ratio and stability of these devices, as well as their repeatable writing, reading and erasing capability with low power consumption, opens up the possibility of the mass production of high performance digital nonvolatile polymer memory devices with low cost. Further, these devices promise to revolutionize microelectronics by providing extremely inexpensive, lightweight, and versatile components that can be printed onto plastics, glasses or metal foils.
Janus Nanoparticles by Interfacial Engineering
Authors: Pradhan S. , Xu L. , Chen S.
Published: August 2007

Nanosized Janus particles were prepared by ligand exchange reactions of a Langmuir monolayer of hydrophobic alkanethiolate‐passivated gold nanoparticles at relatively high surface pressures with hydrophilic thiol derivatives injected into the water subphase. The ligand intercalation between adjacent particles led to impeded interfacial mobility of the particles. Consequently, ligand place‐exchange reactions were limited only to the side of the particles facing the water phase, leading to the formation of amphiphilic nanoparticles which exhibited hydrophobic characters on one side and hydrophilic on the other, analogous to the dual‐face Roman god, Janus. The unique amphiphilic characters of the Janus particles were confirmed by a variety of experimental measurements, including contact angle measurements, FTIR, UV‐visible, and NMR spectroscopies. Interestingly, the Janus particles might be dispersed in water, forming micelle‐like aggregates, as revealed in dynamic light scattering and AFM measurements.
Mesostructured Silica Supports for Functional Materials and Molecular Machines
Authors: Angelos S. , Johansson E. , Stoddart J. F. , Zink J. I.
Published: August 2007

Mesostructured silica thin films and particles prepared by surfactant‐templated sol–gel techniques are highly versatile substrates for the formation of functional materials. The ability to deliberately place molecules possessing desired activities in specific spatially separated regions of the nanostructure is an important feature of these materials. Such placement utilizes strategies that exploit the physical and chemical differences between the silica framework and the templated pores. As an example of placement of pairs of molecules, donor and acceptor molecules can be targeted to different regions of mesostructured thin films and energy transfer between them can be measured. The results not only demonstrate the spatial separation but also are used as a molecular ruler to measure the average distance between them. Mesostructured silica is also an excellent support for molecular machines. Molecules that undergo large amplitude motion, when attached to the silica, can function as impellers and nanovalves when activated by light, electrical (redox) and chemical (pH, competitive binding) energy. Derivatized azobenzene molecules, attached to pore walls by using one of the placement strategies, function as impellers that can move other molecules through the pores. Rotaxanes and pseudorotaxanes, placed at pore entrances, function as gatekeepers that can trap and release molecules from the pores when stimulated. Deliberately placed functional molecules on and in mesostructured silica offer many possibilities for both fundamental studies on the nanoscale and for applications in fields as diverse as fluidics, biological drug delivery and controlled release.
Extremely Low‐Threshold Amplified Spontaneous Emission of 9,9′‐Spirobifluorene Derivatives and Electroluminescence from Field‐Effect Transistor Structure
Authors: Nakanotani H. , Akiyama S. , Ohnishi D. , Moriwake M. , Yahiro M. , Yoshihara T. , Tobita S. , Adachi C.
Published: August 2007

By doping 2,7‐bis[4‐(N‐carbazole)phenylvinyl]‐9,9′‐spirobifluorene (spiro‐SBCz) into a wide energy gap 4,4′‐bis(9‐carbazole)‐2,2′‐biphenyl (CBP) host, we demonstrate an extremely low ASE threshold of Eth = (0.11 ± 0.05) μJ cm–2 (220 W cm–2) which is the lowest ASE threshold ever reported. In addition, we confirmed that the spiro‐SBCz thin film functions as an active light emitting layer in organic light‐emitting diode (OLED) and a field‐effect transistor (FET). In particular, we succeeded to obtain linear electroluminescence in the FET structure which will be useful for future organic laser diodes.
Synthesis and characteristics of aqueous reactive urethane oligomer containing sulfoisophthalate sodium salt
Authors: Yen Meng‐Shung , Huang Ching‐Nan , Hong Po‐Da
Published: August 2007

This research studied urethane oligomers, which contains the sulfonic acid group and different reactive groups. First, the transesterification of dimethyl 5‐sulfoisophthalate sodium salt were performed with ethylene glycol or polyethylene glycol of different molecular weights to produce PEG soft chains possessing sulfonic acid group. Subsequently, isophorone diisocyanate used as a hard chain was connected to the two terminals of the sulfonated diols, which finally were blocked by methyl ethyl ketoxime or hydroxyethyl methacrylate or 2, 3‐Epoxy‐1‐propanol to form three kinds of aqueous reactive urethane oligomers (MSE, HSE, and OSE). The MSE oligomer had the greatest particle diameter, particle variance, and streaming current readings; the HSE oligomer, and the OSE oligomer had the second large and the smallest readings of the aforementioned measurements, respectively; whereas the contact angle and surface tension appeared with an opposite trend. Within the thermal properties of oligomer, the Tg of oligomer followed the trend: OSE < HSE < MSE; however, Tm and ΔH show an opposite tendency. With regard to the reactivity of the oligomers toward PET fabric, the add‐on for the variety of oligomers was in the quantity order of MSE > HSE > OSE series, and the washing durability was rated in the order of HSE > MSE > OSE series. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007