bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro Degradation of 2,4,6‐Trinitrotoluene Using Plant Tissue Cultures of Solanum aviculare and Rheum palmatum
Authors: Nepovím A. , Hubálek M. , Podlipná R. , Zeman S. , Vanek T. 
Published: February 2004

AbstractThe degradation of TNT was tested in suspension cultures (Rheum palmatum and Solanum aviculare) and was followed by the identification of degradation products and the determination of the phytotoxicity of TNT to both cultures. The concentration of TNT inhibited the growth of cell cultures by 50 %, i.e., 37.8 mg/ and 38.1 mg/L for Rheum palmatum and Solanum aviculare, respectively. The TNT uptake was studied by determining the concentration of TNT and its degradation products, such as aminodinitrotoluenes and diaminonitrotoluenes, in the cultivation medium as well as in plant cells. The kinetics of the degradation showed that TNT was mostly taken up within 10 hours and 6 hours for S. aviculare and R. palmatum, respectively. Aminodinitrotoluenes were preferentially produced by cultures of S. aviculare, whereas diaminonitrotoluenes and aminodinitrotoluenes were revealed in cultures of R. palmatum. The final concentrations of identified degradation products did not stoichiometrically correspond to the decreased concentration of TNT in the medium. The different concentrations of degradation products in each culture were an indication that the metabolism of TNT is controlled by different enzymatic systems. Therefore, it was concluded that studying different species for TNT degradation is necessary for the search of most suitable candidates for TNT phytoremediation.
Comparison of the Heavy Metal Biosorption Capacity of Active, Heat‐Inactivated and NaOH‐Treated Phanerochaete chrysosporium Biosorbents
Authors: Gürişik E. , Arica M.Y. , Bektaş S. , Genç Ö. 
Published: February 2004

AbstractThree different kinds of Phanerochaete chrysosporium (NaOH‐treated, heat‐inactivated and active) biosorbent were used for the removal of Cd(II) and Hg(II) ions from aquatic systems. The biosorption of Cd(II) and Hg(II) ions on three different forms of Phanerochaete chrysosporium was studied in aqueous solutions in the concentration range of 50–700 mg/L. Maximum biosorption capacities of NaOH‐treated, heat‐inactivated and active Phanerochaete chrysosporium biomass were found to be 148.37 mg/g, 78.68 mg/g and 68.56 mg/g for Cd(II) as well as 224.67 mg/g, 122.37 mg/g and 88.26 mg/g for Hg(II), respectively. For Cd(II) and Hg(II) ions, the order of affinity of the biosorbents was arranged as NaOH‐treated > heat‐inactivated > active. The order of the amount of metal ions adsorbed was established as Hg(II) > Cd(II) on a weight basis, and as Cd(II) > Hg(II) on a molar basis. Biosorption equilibriums were established in about 60 min. The effect of the pH was also investigated, and maximum rates of biosorption of metal ions on the three different forms of Phanerochaete chrysosporium were observed at pH 6.0. The reusability experiments and synthetic wastewater studies were carried out with the most effective form, i.e., the NaOH‐treated Phanerochaete chrysosporium biomass. It was observed that the biosorbent could be regenerated using 10 mM HCl solution, with a recovery of up to 98%, and it could be reused in five biosorption‐desorption cycles without any considerable loss in biosorption capacity. The alkali‐treated Phanerochaete chrysosporium removed 73% of Cd(II) and 81% of Hg(II) ions from synthetic wastewater.
On frequency domain equalization for MC‐CDMA in Nakagami fading channels
Authors: Abdel‐Hafez Mohammed , Li Zexian , Latva‐aho Matti 
Published: February 2004

AbstractIn this letter, we evaluate the performance of multicarrier code division multiple access (MC‐CDMA) in terms of average bit error probability (BEP) in Nakagami fading channels. The results are applicable to MC‐CDMA systems employing coherent demodulation with maximal‐ratio combining (MRC) or equal gain combining (EGC) reception. The effects of fading parameters and number of users are presented. The accuracy of the proposed analysis is demonstrated by computer simulations. The BEP performance of the EGC receiver in the uplink is highly influenced by the fading parameter compared with that of the MRC receiver. The EGC receiver outperforms the MRC receiver in the downlink, but the MRC receiver gives almost the same performance as the EGC in the uplink. Copyright © 2004 AEI
Effects of user distribution on the delay performance of downlink packet access in 3GPP WCDMA networks
Authors: Fu Hua , Thompson John S. 
Published: February 2004

AbstractThis paper is concerned with the effects of user distribution on the delay performance of packet access in wideband code division multiple access (WCDMA) downlink networks. The characteristics of a packet‐switched data traffic model which mimics internet web browsing is presented. The cellular system model is based on the release 4 configuration of the third Generation Partnership Project (3GPP) technical specification. The investigation incorporates traffic channel power allocation, fast power control, data traffic characteristics, data activity factor, different user distributions, hot‐spot scenarios, base station sectorization schemes and antenna beam patterns. Two types of system level Monte‐Carlo simulations are proposed and a performance comparison is given. The results include the overall delay performance and their sensitivities to a diverse set of parameters. Copyright © 2004 AEI
Impact of local coding efficiency on the modelling of flows derived from VBR MPEG2 video coding
Authors: Corlay Patrick , Gazalet Marc Georges , Coudoux François‐Xavier , Grimbert Laurent 
Published: February 2004

AbstractThis Letter proposes a cell generation model based on a MMPP(2) process which aims to simulate the unsmoothed data output from a variable bit rate (VBR) MPEG‐2 video encoder. By taking into account the coding efficiency in some image zones, we have improved the modelling. This coding efficiency is directly related to the properties of the compression methods used and may lead to a periodic phenomena given the inter‐arrival times between data. The developed model integrates this periodicity in order to refine the modelling. Experimental simulations of VBR MPEG video transmission over ATM were performed to validate this approach. The results expressed in terms of the inter‐arrival time characteristics show the improvement brought by accounting for local coding efficiency. Copyright © 2004 AEI
Focal astrocyte loss is followed by microvascular damage, with subsequent repair of the blood‐brain barrier in the apparent absence of direct astrocytic contact
Authors: Willis Colin L. , Nolan Christopher C. , Reith Sharon N. , Lister Timothy , Prior Malcolm J.W. , Guerin Christopher J. , Mavroudis George , Ray David E. 
Published: February 2004

AbstractBlood‐brain barrier (BBB) breakdown is a feature of cerebral ischaemia, multiple sclerosis, and other neurodegenerative diseases, yet the relationship between astrocytes and the BBB integrity remains unclear. We present a simple in vivo model in which primary astrocyte loss is followed by microvascular damage, using the metabolic toxin 3‐chloropropanediol (S‐α‐chlorohydrin). This model is uncomplicated by trauma, ischaemia, or primary immune involvement, permitting the study of the role of astrocytes in vascular endothelium integrity, maintenance of the BBB, and neuronal function. Male Fisher F344 rats given 3‐chloropropanediol show astrocytic damage and death at 4–24 h in symmetrical brainstem and midbrain nuclear lesions, while neurons show morphological changes at 24–48 h. Fluorescent 10 kDa dextran tracers show the BBB leaking from 24 h, progressing to petechial haemorrhage after 48–72 h, with apparent repair after 6 days. BBB breakdown, but not the earlier astrocytic death, is accompanied by a delayed increase in blood flow in the inferior colliculus. An ED1 inflammatory response develops well after astrocyte loss, suggesting that inflammation may not be a factor in starting BBB breakdown. This model demonstrates that the BBB can self‐repair despite the apparent absence of direct astrocytic‐endothelial contact. The temporal separation of pathological events allows pharmacological intervention, and the mild reversible ataxia permits long‐term survival studies of repair mechanisms. © 2003 Wiley‐Liss, Inc.
Regulation of MHC class II expression in glioma cells by class II transactivator (CIITA)
Authors: Takamura Yukio , Ikeda Hideyuki , Kanaseki Takayuki , Toyota Minoru , Tokino Takashi , Imai Kohzoh , Houkin Kiyohiro , Sato Noriyuki 
Published: February 2004

AbstractWe first classified 12 malignant glioma cell lines into three different groups (types 1–3) with respect to major histocompatibility complex (MHC) class II expression and analyzed each group based on the different expression status of the class II transactivator (CIITA) gene. Glioma type 1 (2 of 12) showed constitutive expression of all class II molecules that might be mediated by activation of B cell‐specific CIITA promoter III. Glioma type 2 represented the major phenotype (66.7 %) of malignant glioma cell lines, and MHC class II expression was induced by interferon‐γ (IFN‐γ) in this phenotype. Analysis of glioma tissue samples revealed that CIITA promoter IV was detected in 9 of 11 patients (81.8%); however, promoter III was only in two (18.2%). Moreover, cultured glioma cells obtained from a fresh tumor sample upregulated expression of CIITA and class II molecules in the presence of IFN‐γ, strongly suggesting that glioma type 2 might be predominant in glioma tissues. Glioma type 3 (2 of 12) showed CIITA transcripts but loss of MHC class II expression even in the presence of IFN‐γ. In addition, we determined that the constitutive MHC class II expression in the glioma cell lines (type 1) was the result of transcriptional activation of the CIITA gene. This phenomenon was mediated by global histone acetylation over 6 kb upstream from the transcriptional start site of CIITA promoter III. Moreover, stable transfection of CIITA promoter IV as well as promoter III into MHC class II inducible cell lines restored the constitutive expression of all class II molecules. These studies lay the foundation to understand the molecular basis for the expression of class II molecules in gliomas. © 2003 Wiley‐Liss, Inc.
Different uptake of cobalamin (vitamin B12) by astrocytes and oligodendrocytes isolated from rat spinal cord
Authors: Buccellato Francesca R. , Foi Laura , Veber Daniela , Pravettoni Giulio , Scalabrino Giuseppe 
Published: February 2004

AbstractIn the present study, we hypothesized that cobalamin (Cbl) deficiency might affect astrocytes and oligodendrocytes of rat spinal cord (SC) differently. Radiolabeled Cbl ([Cyano‐14C]cyano‐Cbl) was used to investigate whether the in vitro uptake of Cbl is different in primary cultures of oligodendrocytes and astrocytes. In culture medium supplemented with serum that naturally contains Cbl, the time course of labeled Cbl uptake by neonatal oligodendrocytes had two peaks, at 8 h and 24 h. No uptake was observed when the same cells were cultured in a serum‐free medium and consequently in the absence of Cbl. Oligodendrocytes isolated from adult rat SC showed no uptake under any of the tested conditions. Astrocytes isolated from adult Cbl‐deficient and newborn rat SC, both cultured in a medium supplemented with serum, showed peak Cbl uptake at 8 h and 12 h, respectively, whereas those isolated from the SC of an adult normal rat cultured under the same conditions showed no uptake throughout the experimental period. Astrocytes isolated from normal, Cbl‐deficient adult rats and newborns cultured in a serum‐free medium not containing Cbl, showed a similar trend of Cbl uptake with a peak at 24 h. Oligodendrocytes isolated from Cbl‐deficient rats showed no uptake when cultured in medium with or without serum. This study provides evidence for a difference in the uptake of labeled Cbl between rat SC astrocytes and oligodendrocytes in relation to (1) age of the donor SC, (2) Cbl status of the donor SC, and (3) Cbl deficiency in the incubation medium that facilitates Cbl uptake in neonatal and adult astrocytes. © 2003 Wiley‐Liss, Inc.
Ink‐jet Printing Polymers and Polymer Libraries Using Micropipettes
Authors: de Gans Berend‐Jan , Kazancioglu Emine , Meyer Wilhelm , Schubert Ulrich S. 
Published: February 2004

AbstractSummary: A study is presented on ink‐jet printing polymers, aiming at library generation for combinatorial material science applications, using (optimized) micropipettes. Solvents were successfully ink‐jet printed, up to 160 mPa s viscosity. Printability of polymer solutions decreases strongly with $\overline M _{\rm w}$ and polymer concentration, due to elastic stresses originating from elongational flow in the pipette nozzle. The feasibility of ink‐jet printing to generate arrays of polymer dots and films was demonstrated.An array of square films is shown that was created by printing a solution containing polydisperse polystyrene in acetophenone and 0.1% disperse red 1 to improve the contrast.magnified imageAn array of square films is shown that was created by printing a solution containing polydisperse polystyrene in acetophenone and 0.1% disperse red 1 to improve the contrast.
Linear Combinatorial Synthesis with Fourier Transform Library Analysis
Authors: Schwabacher Alan W. , Johnson Christopher W. , Geissinger Peter 
Published: February 2004

AbstractFeature Article:Combinatorial synthesis procedures that fit a restrictively defined “fully parallel” criterion tend to be extremely efficient methods. We describe how linear library organization allows such synthesis, without loss of synthetic history information, with an example of a peptide library. Fluorescence measurements of several types are used to measure activities. A novel Fourier Transform approach to library data analysis allows robust evaluation of trends. The use of the cladding of optical fibers as linear supports for combinatorial libraries significantly extends the potential applications of the technique, allowing for spatially resolved optical evaluation of library activity using laser pulses propagating through the fiber core. Moreover, by using different fiber cladding materials, the range of chemistries amenable to one‐dimensional combinatorial synthesis is significantly increased. It is noteworthy that the procedure is particularly applicable to the fabrication and evaluation of real‐time sensor arrays.Schematic representation of a fully parallel synthesis on a linear solid support. The result is a sequence of regions on the thread, each bearing a library member.magnified imageSchematic representation of a fully parallel synthesis on a linear solid support. The result is a sequence of regions on the thread, each bearing a library member.
High‐Throughput Experimentation: A Powerful Enabling Technology for the Chemicals and Materials Industry
Authors: Dar Yadunandan L. 
Published: February 2004

AbstractSummary: High‐throughput experimentation (HTE) and combinatorial techniques have become an active area of interest for the materials and chemicals industry. These techniques could lead to faster, safer, and more efficient processes in virtually all industrial areas. This review briefly describes related aspects of the history of HTE and combinatorial methods in the materials and chemicals industry. It further describes the recent interest by the industry in this area in light of filed and granted patent applications, which represent the efforts of various industrial groups. Many aspects of hte, including material synthesis, screening, informatics, and application testing, have been addressed. A survey of these efforts suggests that such methods are recognized as a powerful enabling technology by industry and are potentially game changing. An effort has been made to keep the discussion focused on materials and techniques relevant to chemicals and materials technology, with an emphasis on polymer and synthetic organic chemistry and the analysis of related products. In‐line with this effort, it has been attempted to exclude aspects mostly relevant to biological, genetic, and pharmaceutical technologies.High level of interest from high‐throughput experimentation focused companies, as well as chemical companies in general, in this area of research and development.magnified imageHigh level of interest from high‐throughput experimentation focused companies, as well as chemical companies in general, in this area of research and development.
Evaluation of Process Degradation of Polymer Formulations Utilizing High‐Throughput Preparation and Analysis Methods
Authors: Wroczynski Ronald J. , Rubinsztajn Malgorzata , Potyrailo Radislav A. 
Published: February 2004

AbstractSummary: Polymers exhibit complex degradation mechanisms during their processing and end use. High‐throughput development of new polymer formulations requires new methods for material preparation and measurement of properties. We explore various approaches to increase the throughput and decrease the sample size for evaluating the relative effectiveness of process stabilizers for poly(propylene). Our several measurement methods for rank ordering stabilizer effectiveness are attractive for rapid identification of high performance stabilizers.Combinatorial polymer microextrusion system.magnified imageCombinatorial polymer microextrusion system.
Rapid Screening of New Polymer‐Supported Palladium (II) Bis(3,4,5,6‐tetrahydropyrimidin‐2‐ylidenes)
Authors: Mayr Monika , Buchmeiser Michael R. 
Published: February 2004

AbstractSummary: The synthesis of two 1,3‐diaryl‐3,4,5,6‐tetrahydropyrimidin‐2‐ylidene‐based N‐heterocyclic carbene‐ (NHC) derived palladium complexes, Pd(5‐hydroxy‐1,3‐bis‐(2,4,6‐trimethylphenyl)‐3,4,5,6‐tetrahydropyrimidin‐2‐ylidene) (Ag2Br2Cl4) (10) and Pd(5‐(bicyclo[2.2.1]hept‐5‐ene‐2‐carbonyloxy)‐1,3‐bis‐(2,4,6‐trimethylphenyl)‐3,4,5,6‐tetrahydropyrimidin‐2‐ylidene) (Ag2Br2Cl4) (11) is described. 10 was supported on a PS‐DVB and a Wang resin, respectively, to yield catalysts 12 and 13, while 11 was used for the synthesis of a ring‐opening metathesis precipitation polymerization‐derived support 14. All supports were tested for their activity in Heck‐type reactions using a combinatorial approach.Structure of polymer supported Pd‐catalysts.magnified imageStructure of polymer supported Pd‐catalysts.
Combinatorial Development of Pressure‐Sensitive Adhesives
Authors: Grunlan Jaime C. , Holguin Daniel L. , Chuang Hsiao‐Ken , Perez Isidro , Chavira Aaron , Quilatan Ryan , Akhave Jay , Mehrabi Ali R. 
Published: February 2004

AbstractSummary: Combinatorial libraries of pressure‐sensitive adhesives were prepared and characterized using a spherical probe tester. Force‐displacement profiles generated for each adhesive provided information related to tack, peel, and shear behavior. These data were used to find the best adhesive, which was then used to generate a combinatorial library of varying thickness. These data demonstrate the utility of high‐throughput screening in pressure‐sensitive‐adhesive development.Adhesive daughter plate arranged in 48‐spot array.magnified imageAdhesive daughter plate arranged in 48‐spot array.
Mapping Surface Chemistry and Molecular Orientation with Combinatorial Near‐Edge X‐Ray Absorption Fine Structure Spectroscopy
Authors: Fischer Daniel A. , Efimenko Kirill , Bhat Rajendra R. , Sambasivan Sharadha , Genzer Jan 
Published: February 2004

AbstractSummary: Mapping the bond chemistry and molecular orientation of self‐assembled monolayer gradients on flat surfaces and reaction intermediates in catalyst arrays is made possible using combinatorial near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy. These spatially resolved NEXAFS maps have been made by utilizing synchrotron‐based NEXAFS spectroscopy in conjunction with a computer controlled precision sample manipulator. The NEXAFS maps reveal bond concentration, rehybridization, and orientation of the surface‐bound molecules with sub‐millimeter planar spatial resolution and sub‐monolayer molecular sensitivity. The wide applicability of the combinatorial NEXAFS method is illustrated by mapping: (1) the concentration and molecular orientation of semifluorinated molecules in molecular gradients; (2) the concentration of amino groups in molecular gradients used for nanoparticle templating, and (3) the rehybridization of propylene intermediates on zeolite catalyst arrays used for measuring solid‐state acidity and catalyst activity.The principle of “combinatorial” NEXAFS. The molecular gradient is indicated pictorially by the shading on the specimen.magnified imageThe principle of “combinatorial” NEXAFS. The molecular gradient is indicated pictorially by the shading on the specimen.
Parallel Synthesis and Testing of Catalysts for the Polymerization of Ethylene
Authors: Kolb Peter , Demuth Dirk , Newsam John M. , Smith Michael A. , Sundermann Andreas , Schunk Stephan Andreas , Bettonville Serge , Breulet Jacques , Francois Philippe 
Published: February 2004

AbstractSummary: High throughput methodologies were applied for the synthesis and testing of late transition metal complexes of Fe with bidentate diazabutadiene or tridentate diiminopyridine ligands in the polymerization of ethylene. Fe DIP complexes with ligands derived from amines with two or three annealed aromatic rings were found to be highly active catalysts when activated with methylaluminoxane. This finding can be rationalized based on models previously developed.magnified image
Combinatorial Electrochemical Synthesis and Screening of Mesoporous ZnO for Photocatalysis
Authors: Jaramillo Thomas F. , Baeck Sung‐Hyeon , Kleiman‐Shwarsctein Alan , McFarland Eric W. 
Published: February 2004

AbstractSummary: Automated electrochemical synthesis was used to create combinatorial libraries of mesoporous materials using tri‐block copolymers as structure directing agents (SDA). An example library of 56 ZnO samples was synthesized, varying concentrations (0–15 wt.‐%) of poly(ethylene oxide)‐block‐poly(propylene oxide)‐block‐poly(ethylene oxide) – EO20PO70EO20. High‐throughput photoelectrochemical screening for the measurement of water‐splitting photocatalysis identified peak performance at 3 wt.‐% of the SDA. Lamellar structures and disordered mesopores were observed by TEM and XRD.magnified image