bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nucleobase Oxidation of DNA by (Terpyridyl)chromium(III) Derivatives
Authors: Vaidyanathan Vaidyanathan Ganesan , Nair Balachandran Unni 
Published: March 2004

AbstractThe chromium(III) complexes [Cr(ttpy)2](ClO4)3 (1) and [Cr(Brphtpy)2](ClO4)3 (2), containing the terpyridyl derivatives ttpy and Brphtpy [ttpy = p‐tolylterpyridine; Brphtpy = (p‐bromophenyl)terpyridine] have been synthesized and characterized by ESI‐MS, electronic spectroscopy, and cyclic voltammetry. Absorption titration and thermal denaturation studies reveal that both complexes are moderate binders of calf thymus DNA (CT DNA), while viscosity measurements show that they bind with partial intercalation. Binding of the two chromium complexes to DNA and mononucleotides dGMP, dAMP, dCMP, and dTMP decreases the emission intensity of complex 2. However, the emission intensity of complex 1 is quenched only by DNA and the nucleotides dGMP and dAMP. Excited state potentials of both 1 and 2 have been estimated to be 1.65 and 1.85 V vs. NHE. These results demonstrate that 2 is a stronger photooxidant than 1, and other (diimine)chromium complexes, and that it can oxidize nucleobases. The photonuclease activity of 1 and 2 has been confirmed by gel electrophoresis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Theoretical Investigation of Group 4 Constrained‐Geometry Complexes Featuring Phosphazene and Phosphinimido Arms
Authors: Truflandier Lionel , Marsden Colin J. , Freund Christelle , Martin‐Vaca Blanca , Bourissou Didier 
Published: March 2004

AbstractDensity functional calculations are reported for the neutral and cationic forms of the “CpPN” zirconium complexes E and F featuring a phosphazene and phosphinimido pendant arm, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Activation of H2 and CO by Sulfur‐Rich Nickel Model Complexes for [NiFe] Hydrogenases and CO Dehydrogenases
Authors: Sellmann Dieter , Prakash Raju , Heinemann Frank W. 
Published: March 2004

AbstractReactions of the trinuclear complexes [Ni(RS3)]3 [HS32− = bis(2‐mercaptophenyl)sulfide(2−) (1a) or siS32− = bis(2‐mercapto‐3‐trimethylsilylphenyl)sulfide(2−) (1b)] with nucleophiles L (L = NHPnPr3, NHPCy3, NHSPh2, PnPr3) afforded the corresponding mononuclear complexes [Ni(L)(RS3)] [R = si = SiMe3; L = NHPnPr3 (2b); L = NHPCy3 (3a,b); L = NHSPh2 (4a,b); L = PnPr3 (5a)]. X‐ray structural determinations showed that 2b, 3a, 3b, 4a, and 5a exhibit tetrahedrally distorted planar [Ni(L)(RS3)] fragments. Complex 2b dimerizes through intermolecular N−H···N hydrogen bonding. In contrast to 2b, complexes 3a and 4a exhibit intramolecular hydrogen bonds between thiol groups and NH protons. Complexes 2−4 possess weakly acidic NH protons and undergo D+/NH exchange reactions with D2O or CD3OD. Complexes 2−4 and [Ni(StBu)(RS3)]− (9a,b) also catalyze D2/H+ exchange in [D8]THF/H2O under an elevated pressure of D2 (18 bar), as confirmed by 1H NMR spectroscopy. It is proposed that D2 heterolysis is achieved through attack of the Lewis‐acidic nickel centers and the Brönsted‐basic sulfur atoms at an η2‐D2 ligand. Complexes 9a and 9b are the first sulfur‐only nickel complexes that enable the modeling of the [NiFe] hydrogenase catalyzed D2/H+ exchange reaction. Evidence for labile five‐coordinate [Ni(CO)(L)(RS3)] has been found in the reaction between [Ni(L)(RS3)] complexes and CO. The CO adducts of complexes with nitrogenous ligands L such as N3−, NHPR3 (R = nPr3, Cy3), or NHSPh2 showed rapid consecutive reactions. The reaction between Et4N[Ni(N3)(siS3)] (8b) and CO gave Et4N[Ni(NCO)(siS3)] (10b), whereas reactions between 2−4 and CO afforded only 1a or 1b. Mechanisms are suggested which have the formation of reactive five‐coordinated [Ni(CO)(L)(RS3)] intermediates in common. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Switch of the Lowest Excited‐States of Terpyridylplatinum(II) Acetylide Complexes Bearing Amino or Azacrown Moieties by Proton and Cations
Authors: Yang Qing‐Zheng , Tong Qing‐Xiao , Wu Li‐Zhu , Wu Zi‐Xin , Zhang Li‐Ping , Tung Chen‐Ho 
Published: March 2004

AbstractThe investigation of the synthesis and unique photophysical properties of two terpyridylplatinum(II) acetylide complexes [Pt(terpy)(C≡CC6H4‐4‐R)] where terpy is 2,2′:6′,2′′‐terpyridyl and R = N(CH3)2(1) orN‐15‐monoazacrown‐5 (2) has been carried out. These complexes exhibit an absorption band in the region of 460−650 nm in neutral or basic solution that corresponds to a ligand‐to‐ligand charge transfer (LLCT) transition from the amino‐substituted acetylide to the terpyridyl acceptor. In acidic solutions the complexes show the lowest‐energy absorption band at 380−500 nm, which is assignable to a dπ(Pt)→π*(terpy) metal‐to‐ligand charge transfer (MLCT) transition. In acidic media the complexes are emissive with quantum yields of 1 × 10−3to 2 × 10−3, and lifetimes of 20−50 ns. Compound2may complex metal cations through its azacrown ether moiety. For Na+, Ba2+, Ca2+and Mg2+, a 1:1 binding mode with logKs of 2.52 to 4.18 was observed. As in the case of acidic solution, the cation‐bound complex also features the lowest‐lying MLCT excited state. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Differential mutagen sensitivity of peripheral blood lymphocytes from smokers and nonsmokers: Effect of human cytomegalovirus infection
Authors: Albrecht Thomas , Deng Cheng Zong , Abdel‐Rahman Sherif Z. , Fons Michael , Cinciripini Paul , El‐Zein Randa A. 
Published: March 2004

AbstractWe used the mutagen sensitivity assay to test the hypothesis that human cytomegalovirus (HCMV) infection modifies the sensitivity of cells to genetic damage from genotoxic agents. Chromosome aberration (CA) frequency in peripheral blood lymphocytes (PBLs) from 20 smokers who were matched with 20 nonsmokers by age (± 5 years), sex, and ethnicity was evaluated following in vitro exposure to bleomycin and/or HCMV infection. Bleomycin induced significant (P < 0.05) concentration‐dependent increases in the frequency of aberrant cells, chromatid‐type damage (breaks), and chromosome‐type aberrations (deletions, rearrangements) in PBLs. The baseline (background) CA frequency was similar in both smokers and nonsmokers. Significantly higher frequencies of aberrant cells (P < 0.05) were observed in PBLs from smokers compared to nonsmokers at all bleomycin concentrations tested (10, 30 and 100 μg/ml). Infection of PBLs with HCMV induced a significant (P < 0.05) twofold increase in the frequency of CA (primarily chromatid breaks) in PBLs, regardless of the smoking status. PBLs from smokers and nonsmokers infected with HCMV prior to challenge with bleomycin demonstrated significant (P < 0.05) concentration‐dependent increases in the levels of aberrant cells, chromatid‐type damage (breaks), and chromosome‐type aberrations (deletions, rearrangements) compared to noninfected cells challenged with bleomycin. The frequency of induced CA was consistently higher for PBLs derived from smokers relative to nonsmokers (P = 0.06 and 0.002). These data indicate that, individually, both smoking and HCMV infection significantly enhance the sensitivity of PBLs to bleomycin‐induced genetic damage. More importantly, the data also suggest that smoking and HCMV infection interact synergistically to enhance the sensitivity of PBLs to such damage. Environ. Mol. Mutagen. 43:169–178, 2004. © 2004 Wiley‐Liss, Inc.
DNA adducts and mutagenic specificity of the ubiquitous environmental pollutant 3‐nitrobenzanthrone in Muta Mouse
Authors: Arlt Volker M. , Zhan Li , Schmeiser Heinz H. , Honma Masamitsu , Hayashi Makoto , Phillips David H. , Suzuki Takayoshi 
Published: March 2004

Abstract3‐nitrobenzanthrone (3‐NBA) is an extremely potent mutagen in the Salmonella reversion assay and a suspected human carcinogen identified in diesel exhaust and in ambient airborne particulate matter. To evaluate the in vivo mutagenicity of 3‐NBA, we analyzed the mutant frequency (MF) in the cII gene of various organs (lung, liver, kidney, bladder, colon, spleen, and testis) in lambda/lacZ transgenic mice (Muta Mouse) after intraperitoneal treatment with 3‐NBA (25 mg/kg body weight injected once a week for 4 weeks). Increases in MF were found in colon, liver, and bladder, with 7.0‐, 4.8‐, and 4.1‐fold increases above the control value, respectively, whereas no increase in MF was found in lung, kidney, spleen, and testis. Simultaneously, induction of micronuclei in peripheral blood reticulocytes was observed. The sequence alterations in the cII gene recovered from 41 liver mutants from 3‐NBA‐treated mice were compared with 32 spontaneous mutants from untreated mice. Base substitution mutations predominated for both the 3‐NBA‐treated (80%) and the untreated (81%) groups. However, the proportion of G:C→T:A transversions in the mutants from 3‐NBA‐treated mice was higher (49% vs. 6%) and the proportion of G:C→A:T transitions was lower than those from untreated mice (10% vs. 66%). The increase in MF in the liver was associated with strong DNA binding by 3‐NBA, whereas in lung, in which there was no increase in MF, a low level of DNA binding was observed (268.0–282.7 vs. 8.8–15.9 adducts per 108 nucleotides). DNA adduct patterns with multiple adduct spots, qualitatively similar to those formed in vitro after activation of 3‐NBA with nitroreductases and in vivo in rats, were observed in all tissues examined. Using high‐pressure liquid cochromatographic analysis, we confirmed that all major 3‐NBA‐DNA adducts produced in vivo in mice are derived from reductive metabolites bound to purine bases (70–80% with deoxyguanosine and 20–30% with deoxyadenosine in liver). These results suggest that G:C→T:A transversions induced by 3‐NBA are caused by misreplication of adducted guanine residues through incorporation of adenine opposite the adduct (A‐rule). Environ. Mol. Mutagen. 43:186–195, 2004. © 2004 Wiley‐Liss, Inc.
Nitrogen oxides emissions reduction technologies in the petrochemical and refining industries
Authors: Baukal Charles E. , Hayes Robert , Grant Mike , Singh Prem , Foote Darin 
Published: March 2004

AbstractIn the petrochemical and refining industries, increasingly stringent regulatory requirements have prompted the development and use of new technologies to minimize nitrogen oxides (NOx) emissions from fired process heaters. Stricter regulations and an increasingly competitive market present significant challenges for petrochemical and refining plants in meeting NOx emissions regulations. The capability of a chosen technology to meet the desired NOx emissions requirements is fundamental to the selection process. Additional factors to consider when evaluating these new technologies include capital and operating costs, downtime, increased complexity of operation and maintenance, safety, and the effects on process heater variables.This paper considers the problem of economically meeting stricter emissions regulations, presents a general discussion of potential options to meet those requirements, compares the advantages and disadvantages of each with respect to the previously mentioned factors, and presents a case study showing the implementation of a new low NOx burner design which proved much more cost effective and retrofittable than the implementation of a catalytic posttreatment control strategy in a refinery. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 19–28, 2004
Evaluation of industrial biotrickling filter at the flexographic printing facility
Authors: Popov Vladimir O. , Bezborodov Alexey M. , Cavanagh Mary , Cross Phillip 
Published: March 2004

AbstractWhile biofiltration and bioscrubbing have already established themselves as standard methods of volatile organic compound (VOC) and odor control, trickling bed biofilter applications are mainly confined to laboratory studies, with only a few installed systems reported in industrial operation. An example of successful industrial biotrickling filter application, controlling highly variable loads of water soluble VOCs at a flexographic printing facility, is presented. The biotrickling filter operates at 14 s contact time and removes on average 7 kg of mixed water‐soluble solvents per hour (280 g per m3 of carrier per hour). The plant is fully compliant with the EC Council Directive 1999/13/EC on the limitation of emissions of VOCs. The operating costs of a biotrickling filter are discussed. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 39–44, 2004
A model for estimating process emissions from gas sweep operations in batch and continuous chemical operations
Authors: Hatfield J. Allen 
Published: March 2004

AbstractA nitrogen gas sweep is commonly applied to the headspace of a vessel to provide an inert atmosphere. A positive pressure of nitrogen also helps to prevent moisture from entering the vessel and having an adverse impact on the process chemistry. In other processing situations air may sweep through the vessel headspace and leave through the process vent. Evaporation of the volatile solvent takes place within the vessel as contact is made between the fresh supply of nitrogen or air and the liquid contents. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 45–51, 2004
Optimal control of material concentration using Fourier series
Authors: Fujii Hiroyuki , Kawahara Mutsuto 
Published: March 2004

Abstract This paper presents an optimal control of the material concentration using Fourier series and finite element method. It is assumed that the optimal control value can be expanded into a Fourier series. The Fourier coefficient is identified to minimize the performance function and the optimal control value is determined. The Sakawa–Shindo algorithm is used for the minimization algorithm. The advection–diffusion equation and shallow water equation are used for the analysis of material concentration and water flow. The Crank–Nicolson scheme and finite element method using bubble function element with stabilized control parameter are employed as temporal and special discretization. Copyright © 2004 John Wiley & Sons, Ltd.
A parallel cell‐based DSMC method on unstructured adaptive meshes
Authors: Kim Min Gyu , Kim Hyoung Soon , Kwon Oh Joon 
Published: March 2004

AbstractA parallel DSMC method based on a cell‐based data structure is developed for the efficient simulation of rarefied gas flows on PC‐clusters. Parallel computation is made by decomposing the computational domain into several subdomains. Dynamic load balancing between processors is achieved based on the number of simulation particles and the number of cells allocated in each subdomain. Adjustment of cell size is also made through mesh adaptation for the improvement of solution accuracy and the efficient usage of meshes. Applications were made for a two‐dimensional supersonic leading‐edge flow, the axi‐symmetric Rothe's nozzle, and the open hollow cylinder flare flow for validation. It was found that the present method is an efficient tool for the simulation of rarefied gas flows on PC‐based parallel machines. Copyright © 2004 John Wiley & Sons, Ltd.
Neuropathological consequences of delivering an adenoviral vector in the rat brain
Authors: McMenamin M. Mary , Lantos Tibor , Carter Emma E. , Hamilton Louise , Charlton Harry M. , Gonzalez S. Charlotte , Wood Matthew J. A. 
Published: March 2004

AbstractBackgroundAdenoviruses have many advantages as vehicles for gene delivery to the central nervous system (CNS) and retrograde transport of vectors to axonally linked sites has been postulated as a method for targeting neurons in remote brain regions. To investigate optimisation of this we injected different doses of vector and have documented the neuropathological side effects.MethodsIncreasing doses of a first‐generation adenoviral vector, expressing the lacZ gene, were inoculated in the rat striatum and β‐galactosidase expression was examined at the primary and secondary sites. Subsequently, at the highest dose of vector, transgene expression, the inflammatory response, tyrosine hydroxylase (TH) expression and the rotational behaviour of animals were studied over time.ResultsWhen a high dose of an adenoviral vector was delivered to the rat striatum, high levels of transgene expression were seen at 5 days in the injection site and in the substantia nigra. Smaller doses gave lower levels of expression with little expression detectable in the substantia nigra. At later time points, with the high dose, a marked reduction in transgene expression was detected and was accompanied by cytopathic damage, a strong inflammatory response and animal weight loss. This was associated with depletion in TH levels and abnormal motor behaviour in animals.ConclusionsNeuropathological damage in the dopaminergic system, caused by high doses of adenoviral vectors, has not previously been documented. To minimise damage and prolong transgene expression, it is important that the dose of vectors to be delivered is carefully optimised. Copyright © 2004 John Wiley & Sons, Ltd.
Hydrodynamics‐based transfection of the liver: entrance into hepatocytes of DNA that causes expression takes place very early after injection
Authors: Andrianaivo Fanjam , Lecocq Michèle , Wattiaux‐De Coninck Simone , Wattiaux Robert , Jadot Michel 
Published: March 2004

AbstractBackgroundThe mechanism of gene transfer into hepatocytes by the hydrodynamics‐based transfection procedure is not clearly understood. It has been shown that, after a hydrodynamic injection, a large proportion of plasmid DNA remains intact in the liver where it is bound to plasma membrane and suggested that this DNA could be responsible for the efficiency of the transfection.MethodsWe have investigated the problem by giving mice a hydrodynamic injection of isotonic NaCl, followed at different time intervals by a conventional injection of DNA, cold or labelled with 35S, with cDNA of luciferase as a reporter gene. Then, we determined the consequences of that dual injection on luciferase expression and on DNA uptake by the liver and its intracellular fate. By such experiments, it is possible to establish the time dependency of the induction of liver changes caused by a hydrodynamic injection on the one hand and the expression and DNA uptake and fate on the other. Moreover, some experiments have been performed on primary cultures of hepatocytes isolated after a hydrodynamic injection of DNA.ResultsWhen DNA is given to mice by a conventional injection a few seconds after an hydrodynamic injection of isotonic NaCl, luciferase expression in the liver is considerably lower than that observed after a single hydrodynamic injection of the plasmid. On the other hand, as assessed by the rate of DNA degradation and by centrifugation results obtained after injection of 35S‐DNA, the uptake and the intracellular fate of the bulk of DNA are similar whether DNA is administered by a single hydrodynamic injection or by a conventional injection given up to at least 2 h after a hydrodynamic injection of isotonic NaCl. Hepatocytes isolated a few minutes after a hydrodynamic injection exhibit a maximal expression that does not depend on the large amount of DNA that remains bound to the plasma membrane for a relatively long time.ConclusionsOur results show that the efficiency of hydrodynamics‐based transfection depends on a process that takes place very quickly after injection and is not linked to a delay of DNA degradation and the persistence of a large proportion of DNA bound to hepatocytes of the plasma membrane, strongly suggesting that expression after a hydrodynamic injection is caused by a small proportion of DNA molecules that rapidly enter the cytosol probably by plasma membrane pores generated by the hydrodynamic pressure. Copyright © 2004 John Wiley & Sons, Ltd.
Insights into the mechanism of magnetofection using PEI‐based magnetofectins for gene transfer
Authors: Huth Stephanie , Lausier James , Gersting Soeren W. , Rudolph Carsten , Plank Christian , Welsch Ulrich , Rosenecker Joseph 
Published: March 2004

AbstractBackgroundGene delivery by the use of magnetic forces, so‐called magnetofection, has been shown to enhance transfection efficiency of viral and non‐viral systems up to several‐hundred‐fold. For this purpose gene carriers, such as polyethylenimine (PEI), are associated with superparamagnetic nanoparticles and complexed with plasmid DNA. Gene delivery is targeted by the application of a magnetic field.MethodsTo investigate the underlying mechanism, we studied the impact of the applied magnetic field on the transfection process of PEI‐coated superparamagnetic iron oxide gene vectors (magnetofectins) using various cell lines. In particular, we addressed the question whether accelerated sedimentation of magnetofectins is the driving force or if the magnetic field itself directly influences the endocytic processing of the magnetofectins. The cellular uptake mechanism of magnetofectins was studied by electron microscopy and transfection experiments in the presence of various inhibitors that operate at different steps of endocytosis.ResultsIn this study we could show that cellular uptake of magnetofectins proceeds obviously by endocytosis. Cellular uptake of magnetofectins behaves almost analogously as compared with PEI polyplexes. Besides unspecific endocytosis, apparently clathrin‐dependent as well as caveolae‐mediated endocytic uptake is involved.ConclusionsThe magnetic field itself does not alter the uptake mechanism of magnetofectins. Obviously, the magnetic forces lead to an accelerated sedimentation of magnetofectins on the cell surface and do not directly affect the endocytic uptake mechanism. So further improvement of magnetic field application could lead to efficient targeting of gene expression into the desired organ and tissuein vivo. Copyright © 2004 John Wiley & Sons, Ltd.
An efficient targeted radiotherapy/gene therapy strategy utilising human telomerase promoters and radioastatine and harnessing radiation‐mediated bystander effects
Authors: Boyd Marie , Mairs Robert J. , Keith W. Nicol , Ross Susan C. , Welsh Philip , Akabani Gamal , Owens Jonathan , Vaidyanathan Ganesan , Carruthers Ross , Dorrens Jennifer , Zalutsky Michael R. 
Published: March 2004

AbstractBackgroundTargeted radiotherapy achieves malignant cell‐specific concentration of radiation dosage by tumour‐affinic molecules conjugated to radioactive atoms. Combining gene therapy with targeted radiotherapy is attractive because the associated cross‐fire irradiation of the latter induces biological bystander effects upon neighbouring cells overcoming low gene transfer efficiency.MethodsWe sought to maximise the tumour specificity and efficacy of noradrenaline transporter (NAT) gene transfer combined with treatment using the radiopharmaceutical meta‐[131I]iodobenzylguanidine ([131I]MIBG). Cell‐kill was achieved by treatment with the β‐decay particle emitter [131I]MIBG or the α‐particle emitter [211At]MABG. We utilised our novel transfected mosaic spheroid model (TMS) to determine whether this treatment strategy could result in sterilisation of spheroids containing only a small proportion of NAT‐expressing cells.ResultsThe concentrations of [131I]MIBG and [211At]MABG required to reduce to 0.1% the survival of clonogens derived from the TMS composed of 100% of NAT gene‐transfected cells were 1.5 and 0.004 MBq/ml (RSV promoter), 8.5 and 0.0075 MBq/ml (hTR promoter), and 9.0 and 0.008 MBq/ml (hTERT promoter), respectively. The concentrations of radiopharmaceutical required to reduce to 0.1% the survival of clonogens derived from 5% RSV/NAT and 5% hTERT/NAT TMS were 14 and 23 MBq/ml, respectively, for treatment with [131I]MIBG and 0.018 and 0.028 MBq/ml, respectively, for treatment with [211At]MABG.ConclusionsThese results indicate that the telomerase promoters have the capacity to drive the expression of the NAT. The potency of [211At]MABG is approximately three orders of magnitude greater than that of [131I]MIBG. Spheroids composed of only 5% of cells expressing NAT under the control of the RSV or hTERT promoter were sterilised by radiopharmaceutical treatment. This observation is indicative of bystander cell‐kill. Copyright © 2004 John Wiley & Sons, Ltd.