bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concerning the preparation and use of substances with a magnetic susceptibility equal to the magnetic susceptibility of air
Authors: Bakker Chris J.G. , de Roos Remmert 
Published: October 2006

AbstractIn this work it is demonstrated that the susceptibility of diamagnetic substances, such as water and agarose gel, can easily be tuned to the susceptibility of air by the addition of a proper amount of strongly paramagnetic ions, in this case 16.6 ± 0.1 mM holmium(III). The resultant air‐equivalent substances are shown to allow the creation of objects that do not disturb the static magnetic field of the scanner and hence do not invoke susceptibility artifacts, regardless of the objects' shape, size, and orientation with respect to B0, and regardless of the pulse sequence being used. The addition of the proper amount of holmium(III) to aqueous solutions and gels is further shown to exert a negligible influence on the chemical shift and to cause a moderate increase of the relaxation rates 1/T1 and 1/T2. The results indicate the potential of air‐equivalent substances for many purposes, including construction of artifact‐free test objects; experimental setups and accessory devices; investigation of systems that contain air cavities, gas bubbles, etc.; and monitoring of system‐related and object‐induced field disturbances. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Bullatencin, 4‐deoxyasimicin, and the uvariamicins: Additional bioactive annonaceous acetogenins from Annona bullata rich. (Annonaceae)
Authors: Hui Yu‐Hua , Wood Karl V. , McLaughlin Jerry L. 
Published: October 2006

AbstractAdditional bioactive Annonaceous acetogenins have been isolated from the EtOH extract of the bark of Annona bullata Rich. by bioactivity‐directed fractionation using lethality to brine shrimp. These acetogenins include bullatencin, a new single tetrahydrofuran acetogenin having a double bond in the hydrocarbon chain; 4‐deoxyasimicin, a new adjacent bis‐tetrahydrofuran acetogenin; and the uvariamicins, an isomeric mixture of four single tetrahydrofuran acetogenins. These acetogenins showed selective cytotoxicities for certain human solid tumor cell lines comparable to or better than adriamycin. © 1992 Wiley‐Liss, Inc.
Kinetics of Alexandrium minutum halim toxin accumulation in mussels and clams
Authors: Lassus P. , Ledoux M. , Bardouil M. , Bohec M. , Erard E. 
Published: October 2006

AbstractMussels (Mytilus edulis) and clams (Ruditapes philippinarum) were contaminated experimentally using cultures of Alexandrium minutum, a toxic dinoflagellate isolated from French coastal waters. Experiments were carried out in continually flushed and open‐circuit systems using Alexandrium densities of 100 to 700 cells/ml delivered to tanks containins the shellfish. All experiments indicated an inversion of the relative proportions of sonyautoxins (GTX2 and GTX3) in shellfish meat during decontamination, whereas saxitoxin (SIX) only accumulated during mussel depuration. However, in mussels a density as low as 100 cells/ml led within 10 days to bioaccumulation of paralytic shellfish poisoning (PSP) toxins above the public health threshold. Similar results were observed in clams subjected to fivefold higher cell densities, indicating a less effective assimilation of the dinoflagellate than by mussel. Decontamination experiments on PSP toxin‐contaminated mussels (360 μs STX eq./100 g or lower uptake) fed two nontoxic diets (1,000 and 10,000 cells/ml of Tetraselmis suesica) showed an appreciable reduction in the time needed to decrease toxin concentration below the accepted threshold for human consumption. We suggest that a simple relation can be established between initial toxicity, the concentration of nontoxic alga available, and the time required for depuration once decontamination kinetics becomes linear and corresponds to the inverse of contamination kinetics. © 1994 wiley‐Liss, Inc.
A specific and sensitive method for the determination of linamarin in urine
Authors: Carisson Lena , Mlingi Nicholas , Ronquist Gunnar , Rosling Hans 
Published: October 2006

AbstractA method is described for the quantitative determination of the cyanogenic glycoside linamarin. A preseparation procedure for urine samples was necessary to remove interfering substances. This was done by solid‐phase extraction on a silica column containing cyclohexyl functional groups, which retained linamarin but allowed thiocyanate to pass unrestricted through the column. After elution of linamarin from the column by 35% (v/v) aqueous methanol, the glycoside was quantified following enzymatic hydrolysis, using the specific enzyme linamarase, and the free cyanide thus liberated was estimated spectrophotometrically. This method allowed quantification of linamarin in urine down to 10 μmol/l, with an estimated recovery of 91%. In 75 Tanzanian subjects consuming insufficiently processed cassava, the mean (± SD) urinary linamarin concentration was 104 (± 104) μmol/l (range 0‐644 n,mol/L), while that for thiocyanate was 486 (μ 451) μmol/l (range 10‐2,940 μmol/l), giving an approximate 15 molar concentration ratio between urinary linamarin and thiocyanate. © 1995 Wiley‐Liss, inc.
Hautdurchdringung ätherischer Öle. Pharmakokinetische Untersuchungen
Authors: Weyers Wolfgang , Brodbeck Rudolf 
Published: October 2006

AbstractVolatile oils are frequently employed in the local treatment of pain. 1,8‐Cineole, the principal component of eucalyptus oil, was used as a model substance to determine whether this active component can be detected in effective amounts at the target area in the skeletal muscles after at the target area in the skeletal muscles after dermal application. The investigation showed surprisingly large differences depending on the manner of application. The relative bioavailability of the model substance 1,8‐cineole obtained by using an applicator was 320% as compared with that obtained by using an occlusive dressing. This has practical effects on the dosage and on the frequency of application.
Benzomorphananaloge Tricyclen: Synthese und Pharmakologische Eigenschaften
Authors: Wünsch Bernhard 
Published: October 2006

AbstractProf. Dr. B. Wünsch wurde 1995 von der Deutschen Pharmazeutischen Gesellschaft auf seiner Jahrestagung in Jena mit dem Johann‐Wolfgang‐Döbereiner‐Preis ausgezeichnet. Diesen Preis vergibt die DPhG zur Förderung des wissenschaftlichen Nachwuchses speziell zur Anerkennung überdurchschnittlicher Habilitationen. Er ist verbunden mit einer materiellen Anerkennung von 10.000 DM, die zur Förderung der weiteren wissenschaftlichen Arbeit bestimmt ist. Mit der Annahme des Preises verpflichtet sich der Preisträger, seine Forschungsergebnisse in einer allgemein verständlichen Form der Wissenschaftlichen Öffentlichkeit vorzustellen.
Diacid architecture effect on the synthesis and microstructure of rigid‐rod poly(benzobisthiazole)s
Authors: Chen Chien‐Fan , Juang Lih‐Jeng , Hsu Tzu‐Chien , Wang Jeh‐Jeng , Wang Li‐Fang 
Published: October 2006

AbstractSix poly(benzobisthiazole)s (PBTs) have been synthesized by the solution polycondensation of 2,5‐diamino‐1,4‐benzenedithiol in poly(phosphoric acid) (PPA) with systematically varied diacids to demonstrate the diacid architecture effect of the aromatic heterocyclic rigid‐rod polymers. The role of PPA is identified and the effects of phosphorus pentoxide and water on PBT during polycondensation are discussed. Polymer properties such as the inherent viscosity and decomposition temperature are correlated to the diacid chemistry. The effect of diacid architecture on the synthesis and microstructure of PBT is studied. The results are discussed in terms of resonance, symmetry, and solubilization of the diacids. Copyright © 2006 Society of Chemical Industry
Biodegradable polymers applied in tissue engineering research: a review
Authors: Martina Monique , Hutmacher Dietmar W 
Published: October 2006

AbstractTypical applications and research areas of polymeric biomaterials include tissue replacement, tissue augmentation, tissue support, and drug delivery. In many cases the body needs only the temporary presence of a device/biomaterial, in which instance biodegradable and certain partially biodegradable polymeric materials are better alternatives than biostable ones. Recent treatment concepts based on scaffold‐based tissue engineering principles differ from standard tissue replacement and drug therapies as the engineered tissue aims not only to repair but also regenerate the target tissue. Cells have been cultured outside the body for many years; however, it has only recently become possible for scientists and engineers to grow complex three‐dimensional tissue grafts to meet clinical needs. New generations of scaffolds based on synthetic and natural polymers are being developed and evaluated at a rapid pace, aimed at mimicking the structural characteristics of natural extracellular matrix. This review focuses on scaffolds made of more recently developed synthetic polymers for tissue engineering applications. Currently, the design and fabrication of biodegradable synthetic scaffolds is driven by four material categories: (i) common clinically established polymers, including polyglycolide, polylactides, polycaprolactone; (ii) novel di‐ and tri‐block polymers; (iii) newly synthesized or studied polymeric biomaterials, such as polyorthoester, polyanhydrides, polyhydroxyalkanoate, polypyrroles, poly(ether ester amide)s, elastic shape‐memory polymers; and (iv) biomimetic materials, supramolecular polymers formed by self‐assembly, and matrices presenting distinctive or a variety of biochemical cues. This paper aims to review the latest developments from a scaffold material perspective, mainly pertaining to categories (ii) and (iii) listed above. Copyright © 2006 Society of Chemical Industry
Surface characterization and barrier properties of plasma‐modified polyethersulfone/layered silicate nanocomposites
Authors: Wu Tzong‐Ming , Yang Shih‐Hsien 
Published: October 2006

AbstractThis study describes the preparation of polyethersulfone (PES)/layered silicate nanocomposites (PLSNs) by mixing PES polymer chain into organically‐modified layered silicate in 1‐methyl‐2‐pyrrolidinone (NMP) solution. Both X‐ray diffraction data and transmission electron microscopy images of PLSNs indicate that the silicate layers were almost exfoliated and randomly distributed into the PES matrix. The mechanical and barrier properties of PLSNs show remarkable enhancement in the storage modulus and water/oxygen permeability when compared with that of neat PES matrix. Surfaces modification of PES and PLSN films with various treated times, system pressures, and radio frequency (RF) powers were performed using a mixture of oxygen (O2) and nitrogen (N2) plasmas. The topographical and physical properties of plasma‐modified PES and PLSN surfaces were investigated using scanning probe microscopy (SPM), contact‐angle measurements, and X‐ray photoelectron spectroscopy (XPS). These results indicate that the surface roughness of PLSNs with the same condition of plasma modification is lower than that of neat PES matrix and is probably due to the increase of stiffness with the presence of inorganic layered silicates in PES matrix. The surface properties of the PES and PLSNs are also changed from hydrophobic to hydrophilic. The XPS spectra suggest that the exposure of the PES and PLSNs to the plasmas led to the combination of etching reactions of polymer surface initiated by plasma and the following addition reactions of new oxygen‐ and nitrogen‐containing functional groups onto polymer surfaces to change their surface properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3185–3194, 2006
Evaluation of piezoelectric PVDF polymers for use in space environments. III. Comparison of the effects of vacuum UV and gamma radiation
Authors: Dargaville Tim R. , Elliott Julie M. , Celina Mathew 
Published: October 2006

AbstractFilms of piezoelectric PVDF and P(VDF‐TrFE) were exposed to vacuum UV (115–300 nm VUV) and γ‐radiation to investigate how these two forms of radiation affect the chemical, morphological, and piezoelectric properties of the polymers. The extent of crosslinking was almost identical in both polymers after γ‐irradiation, but surprisingly, was significantly higher for the TrFE copolymer after VUV‐irradiation. Changes in the melting behavior were also more significant in the TrFE copolymer after VUV‐irradiation due to both surface and bulk crosslinking, compared with only surface crosslinking for the PVDF films. The piezoelectric properties (measured using d33 piezoelectric coefficients and D‐E hysteresis loops) were unchanged in the PVDF homopolymer, while the TrFE copolymer exhibited more narrow D‐E loops after exposure to either γ‐ or VUV‐radiation. The more severe damage to the TrFE copolymer in comparison with the PVDF homopolymer after VUV‐irradiation is explained by different energy deposition characteristics. The short wavelength, highly energetic photons are undoubtedly absorbed in the surface layers of both polymers, and we propose that while the longer wavelength components of the VUV‐radiation are absorbed by the bulk of the TrFE copolymer causing crosslinking, they are transmitted harmlessly in the PVDF homopolymer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3253–3264, 2006
The study of local dual‐peak vibratory properties in ferroelectric P(VDF‐TrFE) films
Authors: Zhu Guodong , Zeng Zhigang , Zhang Li , Yan Xuejian , Li Jie 
Published: October 2006

AbstractIn this article, we reported the studies on the local dual‐peak vibrations in ferroelectric P(VDF‐TrFE) films, induced by an alternating voltage with its amplitude high enough to cause polarization reversal. A further study showed that this dual‐peak vibration was caused by ferroelectric switching process. The buildup of these dual‐peak vibrations had been detected, and the asymmetrical evolution of local butterfly loops was observed. It was believed that the observed time delay during the developments of dual‐peak vibrations and butterfly loops should be attributed to the electrode effect. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3282–3287, 2006
Glow Discharges Observed in Capacitive Radio‐Frequency Atmospheric‐Pressure Plasma Jets
Authors: Laimer Johann , Störi Herbert 
Published: October 2006

AbstractSummary: The APPJ is the subject of intensive recent research. Basically, the APPJ consists of an atmospheric‐pressure RF discharge between two bare metallic electrodes and of a superimposed gas flow consisting predominantly of a rare gas. In its usual operating regime, a uniform glow discharge, which was identified as the α mode of a RF discharge, can be sustained over a wide range of gap spacings and RF powers. Maximum electron densities of 0.22 × 1012 cm−3 were assessed for helium and of 2.75 × 1012 cm−3 for argon by evaluation of electric measurements using a simple equivalent circuit model. At low RF powers, only partial coverage of the electrodes was observed. At high RF powers, a breakdown of the α sheath occurred, and a transition to either a pure γ mode or a coexisting α and γ mode took place. The γ mode covers only a small fraction of the electrode surface. In helium, it was easy to ignite directly a pure α discharge, but not in argon. Due to the high over‐voltage needed, the ignition in argon mostly led to a coexisting α and γ mode. However, through RF power reduction a transition to a pure α discharge can be initiated.Photograph of the APPJ in operation.magnified imagePhotograph of the APPJ in operation.
A First Principles Density Functional Study of Crystalline FOX‐7 Chemical Decomposition Process under External Pressure
Authors: Hu Anguang , Larade Brian , Abou‐Rachid Hakima , Lussier Louis‐Simon , Guo Hong 
Published: October 2006

AbstractWe report on a first principles analysis of chemical decomposition reaction in a crystalline FOX‐7 (1,1‐diamino‐2,2‐dinitroethylene) molecule, which is a good candidate for insensitive energetic materials. Our calculations are based on variable‐cell shape methods under pressure, density functional theory with localized numerical orbital and pseudopotential, together with ab initio biasing molecular dynamics. The calculated crystal structure and equation of state (pressure vs. volume) up to 8 GPa agrees well with the corresponding experimental data. A chemical decomposition by intermolecular hydrogen transfer is found at higher pressure. This decomposition appears to be driven by a weakening in the chemical hardness. This suggests that the molecular HOMO and LUMO orbital energy difference is decreased when intermolecular hydrogen transfers occur, and for the FOX‐7 crystal the band gap is narrowed with increasing external pressure.
Patterning High Explosives at the Nanoscale
Authors: Nafday Omkar A. , Pitchimani Rajasekar , Weeks Brandon L. , Haaheim Jason 
Published: October 2006

AbstractFor the first time, we have shown that spin coating and Dip pen nanolithography (DPNTM) are simple methods of preparing energetic materials such as PETN and HMX on the nanoscale, requiring no heating of the energetic material. Nanoscale patterning has been demonstrated by the DPN method while continuous thin films were produced using the spin coating method. Results are presented for preparing continuous PETN thin films of nanometer thickness by the spin coating method and for controlling the architecture of arbitrary nanoscale patterns of PETN and HMX by the DPN method. These methods are simple for patterning energetic materials and can be extended beyond PETN and HMX, opening the door for fundamental studies at the nanoscale.
Preparation and Characterization of Nano‐TATB Explosive
Authors: Yang Guangcheng , Nie Fude , Huang Hui , Zhao Lin , Pang Wanting 
Published: October 2006

AbstractNano‐TATB was prepared by solvent/nonsolvent recrystallization with concentrated sulfuric acid as solvent and water as nonsolvent. Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) were used to characterize the appearance and the size of the particles. The results revealed that nano‐TATB particles have the shape of spheres or ellipsoids with a size of about 60 nm. Due to their small diameter and high surface energy, the particles tended to agglomerate. By using X‐ray powder diffraction (XRD), broadening of diffraction peaks and decreasing intensity were observed, when the particle sizes decreases to the nanometer size range. The corrected average particle size of nano‐TATB was estimated using the Scherrer equation and the size ranged from 27 nm to 41 nm. Furthermore, the specific surface area and pore diameter of nano‐TATB were determined by BET method. The values were 22 m2/g and 1.7 nm respectively. Thermogravimetric (TG) and Differential Scanning Calorimetric (DSC) curves revealed that thermal decomposition of nano‐TATB occurs in the range of 356.5 °C–376.5 °C and its weight loss takes place at about 230 °C. Furthermore, a slight increase in the weight loss was observed for nano‐TATB in comparison with micro‐TATB.
MIR/NIR/FIR Characterization of Poly‐AMMO and Poly‐BAMO and their Precursors as Energetic Binders to be Used in Solid Propellants
Authors: de Oliveira José Irineu S. , Diniz Milton F. , Kawamoto Aparecida M. , Dutra Rita C. L. , Keicher Thomas 
Published: October 2006

AbstractTo establish the relation between structure and properties of composite solid propellants it is important to know the structure of the elastomeric binder that has been used in the system. Therefore this study is focused on the characterization of polymers containing energetic groups that has been synthesized at ICT. The characterization uses the wide spectral band of infrared, NIR/MIR/FIR. This gives an identification of the analytical bands and allows quantitative and kinetic studies of these compounds.
Characterization and safe handling of reactive initiator solutions
Authors: Klein James A. , Mros Gordon R. 
Published: October 2006

AbstractThe thermal stability of initiators used in free radical polymerizations has been well documented. Initiators are often used in solutions, with relatively long feed periods to help control the heat of polymerization. In some cases, the stability of the initiator solutions is limited, especially at higher concentrations, and runaway reactions can potentially be severe. This article reviews the chemical reactivity of concentrated initiator solutions and considers PHA studies and feed tank design to help ensure safe handling and manufacture. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2006
Evaluation of khat (Catha edulis Forssk) for antifertility activity in rats
Authors: Tariq M. , Parmar N. S. , Islamr M. W. , Ai‐Meshal I. A. 
Published: October 2006

AbstractThe effect of the methanolic extract of khat (Catha edulis Forssk) was studied on female fertility in rats. The parameters included the effect on oestrus cycle, implantation, foetal loss, abortion, inhibition of uterotrophic activity and teratogenicity. The extract, in the doses of 250 and 500 mg/kg, produced dose dependent and significant anti‐implantation activity. However, it failed to produce complete infertility in this dose range. Treatment of animals during day 8 to day 12 of pregnancy produced significant abortifacient activity. There was significant decrease in the weight and length of foetuses delivered by rats treated with the extract but there were no gross abnormalities in the organs of the offsprings. It also produced significant anti‐oestrogenic activity as assessed by the mean weight of the uteri of rats treated with oestradiol and its combination with the khat extract.
Bioactive furanocoumarins from the berries of Zanthoxylum americanum
Authors: Saqib Q. N. , Hui Y.‐H. , Anderson J. E. , McLaughlin J. L. 
Published: October 2006

AbstractCrude extracts of the berries of Zanthoxylum americanum showed significant lethality to brine shrimp larvae and exhibited cytotoxicity to human tumor cells. Activity‐directed fractionation led to 5 furanocoumarins (cnidilin, imperatorin, isoimperatorin, psoralen, and xanthotoxin), the last three of which are bioactive in these bioassays. All were previously known as natural compounds but are new to this plant species.
Inhibition of clastogenic effects of nicotine by chlorophyllin in mice bone marrow cells in vivo
Authors: Sen Soumitra , Sharma Archana , Talukder Geeta 
Published: October 2006

AbstractThe effect of chlorophyllin in modifying the clastogenic action of nicotine was tested in vivo on mice bone marrow cells. Nicotine, when administered by gavage, induced chromosomal aberrations in frequencies directly proportional to the dose. Maximum effects were recorded at 6 h after exposure. Chlorophyllin, when given alone, was not clastogenic even at the highest concentration (1.50 mg/kg body wt). Simultaneous administration of nicotine and chlorophyllin with even lower doses (1.25 and 0.77 mg/kg body wt) reduced the frequency of chromosomal aberrations to the normal level. Chlorophyllin alone, given 2 h before nicotine, however, did not counteract the effects of nicotine. The use of green plant parts in modifying the genotoxicity of different agents may be related to the protective action of chlorophyllin.
Studies on plant resources, pharmacology and clinical treatment with berbamine
Authors: Liu Chang‐Xiao , Xiao Pei‐Gen , Liu Guo‐Sheng 
Published: October 2006

AbstractIn the present paper, the plant resources, chemistry, pharmacology and clinical therapy of berbamine are reported. From a botanical survey it was found that there are 32 species of Berberis plants containing berbamine utilized in China. Pharmacological studies demonstrated that berbamine possesses significant leukogenic effects in rats and dogs injured by an anticancer agent, and clinical observations demonstrated a therapeutic effect in 405 patients with leukopenia. It is suggested that berbamine may not only be useful as a leukogenic drug but is also useful as an adjuvant in cancer chemotherapy and radiotherapy.