bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Rationalisation of Co‐crystals Formed between Trithiocyanuric Acid and Molecules Containing Hydrogen Bonding Functionality
Authors: Ahn Shinbyoung , PrakashaReddy J. , Kariuki Benson M. , Chatterjee Swati , Ranganathan Anupama , Pedireddi V. R. , Rao C. N. R. , Harris Kenneth D. M.
Published: February 2005

Crystallisation of trithiocyanuric acid (TTCA) from various organic solvents that have hydrogen bonding capability (acetone, 2‐butanone, dimethylformamide, dimethyl sulfoxide, methanol and acetonitrile) leads to the formation of co‐crystals in which the solvent molecules are incorporated together with TTCA in the crystal structure. Structure determination by single‐crystal X‐ray diffraction reveals that these co‐crystals can be classified into different groups depending upon the topological arrangement of the TTCA molecules in the crystal structure. Thus, three different types of single‐tape arrangements of TTCA molecules and one type of double‐tape arrangement of TTCA molecules are identified. In all co‐crystals, hydrogen‐bonding interactions are formed through the involvement of NH bonds of TTCA molecules in these tapes and the other molecule in the co‐crystal. Detailed rationalisation of the structural properties of these co‐crystals is presented.
Syntheses and Structures of the First Heavy‐Alkali‐Metal Tris(trimethylsilyl)germanides
Authors: Teng Weijie , Ruhlandt‐Senge Karin
Published: February 2005

The first heavy‐alkali‐metal tris(trimethylsilyl)germanides were obtained in high yield and purity by a simple one‐pot reaction involving the treatment of tetrakis(trimethylsilyl)germane, Ge(SiMe3)4, with various alkali metal tert‐butoxides. The addition of different sizes of crown ethers or the bidentate TMEDA (TMEDA=N,N,N′,N′‐tetramethylethylenediamine) provided either contact or separated species in the solid state, whereas in aromatic solvents the germanides dissociate into separated ions, as shown by 29Si NMR spectroscopic studies. Here we report on two series of germanides, one displaying MGe bonds in the solid state with the general formula [M(donor)nGe(SiMe3)3] (M=K, donor=[18]crown‐6, n=1, 1; Rb, donor=[18]crown‐6, n=1, 4; and M=K, donor=TMEDA, n=2, 6). The silicon analogue of 6, [K(tmeda)2Si(SiMe3)3] (7) is also included to provide a point of reference. The second group of compounds consists of separated ions with the general formula [M(donor)2][Ge(SiMe3)3] (M=K, donor=[15]crown‐5, 2; M=K, donor=[12]crown‐4, 3; and M=Cs, donor=[18]crown‐6, 5). While all target compounds are highly sensitive towards hydrolysis, use of the tridentate nitrogen donor PMDTA (PMDTA=N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine) afforded even more reactive species of the composition [K(pmdta)2Ge(SiMe3)3] (8). We also include the silanide analogue [K(pmdta)2Si(SiMe3)3] (9) for sake of comparison. The compounds were typically characterized by X‐ray crystallography, and 1H, 13C, and 29Si NMR and IR spectroscopy, unless extremely high reactivity, as observed for the PMDTA adducts 8 and 9, prevented a more detailed characterization.
Tin‐Free Radical Alkoxyamine Addition and Isomerization Reactions by Using the Persistent Radical Effect: Variation of the Alkoxyamine Structure
Authors: Molawi Kian , Schulte Tobias , Siegenthaler Kai Oliver , Wetter Christian , Studer Armido
Published: February 2005

Various C‐centered radicals can efficiently be generated through thermal CO‐bond homolysis of alkoxyamines. This method is used to perform environmentally benign radical cyclization and intermolecular addition reactions. These alkoxyamine isomerizations and intermolecular carboaminoxylations are mediated by the persistent radical effect (PRE). In the paper, the effect of the variation of the alkoxyamine structure—in particular steric effects in the nitroxide moiety—on the outcome of the PRE mediated radical reactions will be discussed. Fourteen different nitroxides were used in the studies. It will be shown that reaction times can be shortened about 100 times upon careful tuning of the alkoxyamine structure. Activation energies for the CO‐bond homolysis of the various alkoxyamines are provided. The kinetic data are used to explain the reaction outcome of the PRE‐mediated processes.
Interactions between Brushlike Polyacrylic Acid Side Chains on a Polyacrylate Backbone in Dioxane–Water
Authors: Hua Fengjun , Kita Rio , Wegner Gerhard , Meyer Wolfgang
Published: February 2005

Densely grafted polyacrylic acids (d‐PAAs) with overcrowded PAA side chains on the polyacrylate main chains were synthesized and characterized. Acryloyl poly(tert‐butyl acrylate) macromonomer [M‐P(tert‐BA)] was prepared with a definite chain length (n=29) by atom‐transfer radical polymerization (ATRP), then homopolymerization was carried out to produce densely grafted P(tert‐BA)s with polyacrylate main chains of two different lengths (m=27 and 161). The two d‐PAAs were obtained by hydrolyzing d‐P(tert‐BA)s in the presence of trifluoroacetic acid (TFA). The d‐PAAs exhibit intermolecular and intramolecular hydrogen bonding between the carboxylic groups of PAA side chains in dioxane and pyridine; both were investigated using proton nuclear magnetic resonance (1H NMR) spectroscopy. The intermolecular hydrogen bonding was found to be dependent on polymer concentration, temperature, and water content. The intramolecular association between the PAA side chains was found to produce a contraction of the hydrodynamic volume of the d‐PAA. Intermolecular hydrogen bonding produces aggregates, as demonstrated by dynamic light scattering (DLS). The clusters were found to shrink as the overall water concentration decreased, and this effect is tentatively explained by considering the gradient in chemical potential of water inside the clusters in comparison with the solvent phase.
Selective Fluorescence Recovery after Bleaching of Single E2GFP Proteins Induced by Two‐Photon Excitation
Authors: Chirico G. , Diaspro A. , Cannone F. , Collini M. , Bologna S. , Pellegrini V. , Beltram F.
Published: February 2005

We report the two‐photon excitation and emission of a recently developed green fluorescent protein (GFP) mutant, E2GFP. Two main excitation bands are found at 780 and 870 nm. Blinking and irreversible and reversible bleaching were observed. Fluorescence blinking occurs in the millisecond range and has been ascribed to conversions between the neutral, anionic and dark zwitterionic states. Bleaching is observed after approximately 10 to 4000 ms depending on the excitation power, and it is probably due to a conversion to a dark state. The striking feature of this GFP mutant is that the fluorescence can be recovered with very high efficiency only upon irradiation at 720±10 nm. This GFP mutant therefore seems promising as an almost permanent chromophore for two‐photon excitation (TPE) microscopy or for applications in single‐molecule memory arrays.
The Kinetics of Z/E Isomerization of Methyl Oleate Catalyzed by Photogenerated Thiyl Radicals
Authors: Chatgilialoglu Chryssostomos , Samadi Abdelouahid , Guerra Maurizio , Fischer Hanns
Published: February 2005

The reaction of β‐mercaptoethanol with methyl oleate in tert‐butyl alcohol was investigated under photochemical conditions. The time‐dependent Z/E isomerization of the unsaturated moiety as well as the thiol‐adduct formation were analyzed on the basis of radical generation rates and established rate constants. This provides precise room‐temperature rate constants for the reversible thiyl radical addition to both Z and E isomers. The rate constants for HOCH2CH2S. addition to the Z and E forms were found to be 1.6×105 and 2.9×105 M−1 s−1, respectively. For the β‐elimination of the thiyl radical from the alkyl radical adduct, the rate constants were 1.7×107 and 1.6×108 s−1, the faster associated with the formation of the E isomer. DFT‐BB1K calculations on 2‐butene assign this large preference of fragmentation for the E isomer to a lower activation barrier for the formation of the E transition state from the equilibrium radical adduct structure.
Molecular Adsorption‐Mediated Control over the Electrical Characteristics of Polycrystalline CdTe/CdS Solar Cells
Authors: Visoly‐Fisher Iris , Sitt Amit , Wahab Melina , Cahen David
Published: February 2005

The effect of surface treatments on p‐CdTe/n‐CdS solar cell performance was examined. Adsorption of organic molecules with various magnitudes and directions of the dipole moment on p‐CdTe resulted in controlled changes in electron affinity and surface band bending. Similar adsorption on CdTe in state‐of‐the‐art p‐CdTe/n‐CdS solar cells changes the cell performance, and we explain this by a combination of increased series resistance and changes in light absorption and in cell photovoltage. While at this stage no improvement in performance has been found with these cell structures, which are the result of years of empirical optimization, the molecular effect on the photovoltage shows that it is possible in this way to control the photovoltaic effect at this junction. Separate optimization may well lead to improvement by inserting a dipole layer near the photovoltaic interface. Our results also show that this is even possible when dipole adsorption is performed on the complete polycrystalline thin‐film cell.
One‐ and Two‐Photon Photochemistry and Photophysics of Poly(arylenevinylene)s Containing a Biphenyl Moiety
Authors: Strehmel Veronika , Sarker Ananda M. , Lahti Paul M. , Karasz Frank E. , Heydenreich Matthias , Wetzel Hendrik , Haebel Sophie , Strehmel Bernd
Published: February 2005

Photochemical and photophysical properties were investigated for poly(arylenevinylene)s containing a flexible biphenyl “hinge” unit by applying one‐photon (OP) and two‐photon (TP) excitation to explore excited‐state properties. The poly(arylenevinylene)s were poly[(2,5‐dihexyloxy‐p‐phenylenevinylene)‐alt‐(4,4′‐dihexyloxy‐3,3′‐biphenylenevinylene)] (1), poly[(2,5‐dihexyloxy‐p‐phenylenevinylene)‐alt‐(2,2′‐dihexyloxy‐3,3′‐biphenylenevinylene)] (2), and poly[(2,5‐dihexyloxy‐p‐phenylenevinylene)‐alt‐(2,2′‐biphenylenevinylene)] (3). Effective emission quantum yields and related photonic properties were evaluated on a realistic per‐chromophore basis using effective conjugation lengths based on the Strickler–Berg relationship. Intramolecular photocyclization was deduced to occur in the one case where the biphenyl molecular connectivity permitted the reaction, based on matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF), heteronuclear multiple‐quantum coherence (HMQC)‐NMR, and gel‐permeation chromatography (GPC) results. The various photoprocesses could be induced by either OP or TP excitation, though the first excited singlet state is the photoactive state. The higher excitation energy of the TP excited state favors indirect population of the S1 state by electronic coupling between the TP and OP excited states [λ${{{TPE\hfill \atop max\hfill}}}$ (nm): 726; δ (GM)9: 1=229, 2=215, 3=109). Photochemical processes occurring from the lowest OP excited state (S1) could therefore also be indirectly induced by TP excitation.
Femtosecond Time‐Resolved Geometry Relaxation and Ultrafast Intramolecular Energy Redistribution in Ag2Au
Authors: Bernhardt Thorsten M. , Hagen Jan , Socaciu Liana D. , Mitrić Roland , Heidenreich Andreas , Le Roux Jérôme , Popolan Denisia , Vaida Mihai , Wöste Ludger , Bonačić‐Koutecký Vlasta , Jortner Joshua
Published: February 2005

The ultrafast dynamics of the bimetallic cluster Ag2Au is investigated by pump–probe negative ion‐to‐neutral‐to‐positive ion (NeNePo) spectroscopy. Preparation of the neutral cluster in a highly nonequilibrium state by electron detachment from the mass‐selected anion, and subsequent probing of the neutral nuclear dynamics through two‐photon ionization to the cationic state, leads to strongly probe‐energy‐dependent transient cation‐abundance signals. The origin of this pronounced time and wavelength dependence of the ionization probability on the femtosecond scale is revealed by ab initio theoretical simulations of the transient spectra. Based on the analysis of underlying dynamics, two fundamental processes involving geometry relaxation from linear to triangular structure followed by ultrafast intramolecular vibrational energy redistribution (IVR) have been identified and for the first time experimentally observed in the frame of NeNePo spectroscopy under conditions close to zero electron kinetic energy.
Cover Picture: Femtosecond Time‐Resolved Geometry Relaxation and Ultrafast Intramolecular Energy Redistribution in Ag2Au (ChemPhysChem 2/2005)
Authors: Bernhardt Thorsten M. , Hagen Jan , Socaciu Liana D. , Mitrić Roland , Heidenreich Andreas , Le Roux Jérôme , Popolan Denisia , Vaida Mihai , Wöste Ludger , Bonačić‐Koutecký Vlasta , Jortner Joshua
Published: February 2005

The cover picture shows an artist's view of the dynamical evolution of the bimetallic cluster Ag2Au in the neutral electronic ground state after photodetachment of the anion. Femtosecond negative ion–to‐neutral–to‐positive ion (NeNePo) pump‐probe spectroscopy (open circles) at two different probe wavelengths (blue: 350 nm; red: 406 nm) and theoretical simulations (solid lines) are employed to monitor the dynamical processes of geometry relaxation followed by intramolecular vibrational energy redistribution (IVR) to the probe‐wavelength dependent NeNePo signals. In their Article on page 243 Bernhardt et al. provide detailed insight into the ultrafast nuclear dynamics in this model‐type cluster system.
New lattice structure of M‐channel paraunitary filterbanks
Authors: Kobayashi Yuhiro , Ikehara Masaaki
Published: February 2005

This paper proposes a new lattice structure for the M‐channel paraunitary filterbank. When a filterbank is realized by using a lattice structure, there is an advantage that properties such as phase linearity and the paraunitarity can be retained if the coefficients are quantized. A large number of lattice structures have been proposed, but there remains the problem that the proposed structures contain redundancy. This paper first eliminates the redundancy from the lattice structure and presents a new lattice structure for the generalized filterbank without restrictions such as phase linearity. Based on the proposed structure and restricting the parameters, a pairwise mirror image filterbank structure is presented. Finally, the usefulness of the approach is demonstrated by simulation. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(6): 12–19, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20125
Estimation of soil cracking and the effect on surface runoff in a Texas Blackland Prairie watershed
Authors: Arnold J. G. , Potter K. N. , King K. W. , Allen P. M.
Published: February 2005

Seasonal cracking of the soil matrix results in poor estimates of runoff and infiltration by simulation models due to the changing soil storage conditions. In this study, soil surface elevation changes were measured every two weeks and soil crack volume was calculated for a two‐year period at the USDA‐Agricultural Research Service, Riesel Y‐2 watershed in central Texas. Soil anchors were placed in triplicate at depths of 0·15, 0·45, 0·90, 1·50 and 2·5 m and relative movement from a monument at 4·5 m was measured. Soil movement was translated into crack volume assuming isotrophic shrinkage. A crack flow model was developed for this study that computes crack volume from crack potential, soil depth and soil moisture. Simulated crack volume followed the seasonal trends found in the measured crack volume and was in general agreement with a regression R2 = 0·84. The crack model was incorporated into SWAT (Soil and Water Assessment Tool), a comprehensive hydrologic model. Regression analysis was performed on measured and simulated daily surface runoff with an R2 = 0·87 indicating good agreement. The model was able to simulate surface runoff accurately in winter months when cracks were swelled closed and in the fall recharge events of 1998 when crack volume went from 70 to 10 mm. The relationships between measured crack volume and hydrologic variables simulated by the model were also examined and discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Application and evaluation of ESWAT on the Dender basin and the Wister Lake basin
Authors: Van Griensven A. , Bauwens W.
Published: February 2005

A computer program (ESWAT) was developed to perform integrated water quality modelling for river basins in order to assist water quality management planning and decision‐making. To describe the variabilities in water quality due to the climate, seasonalities and sub‐daily fluctuations, such a model should be able to generate long‐time output series on a sub‐daily basis. This is established by extending the existing program codes of SWAT. While SWAT enables long‐time simulations of agricultural pollution on a daily time step, ESWAT uses a time step of a user‐defined fraction of an hour and an hourly time step to calculate the rainfall/runoff and the in‐stream river routing processes, respectively. The hydrology part was further improved by including a convolution module and modifications of the evapotranspiration module of SWAT. A new module based on the QUAL2E concept was included to simulate the in‐stream water quality processes.

Also, an autocalibration module has been incorporated for the optimization of the process parameters. The method is based on a new approach for multi‐objective calibration and incorporates the shuffled complex evolution (SCE) alogrithm. The optimization uses a global optimization criterion, whereby several output variables can be taken into account simultaneously. A new statistical method enables the aggregation of the objective functions for individual variables, hereby avoiding the weighting problem.

ESWAT is applied on the Dender basin and the Wister Lake basin in Oklahoma, USA. These basins have different characteristics regarding pollution sources, hydrometeorology and scale, and thus provide a wide evaluation of the performance of ESWAT. Copyright © 2005 John Wiley & Sons, Ltd.
Application of SWAT in the evaluation of salmon habitat remediation policy
Authors: Whittaker Gerald
Published: February 2005

Agricultural non‐point source water pollutants such as sediment, pesticides and nutrients have been identified as contributing to the environmental distress of salmon runs in the Pacific Northwest. Policies to control non‐point pollution from agricultural production can be classified as command and control or economic incentive policies. In application of a command and control policy, a regulator (usually a government agency) mandates a reduction in emissions or limits an agricultural production activity. Examples are a mandated reduction in nutrient application, or a reduction in emission of a nutrient to streams. Economic incentive policies are designed to achieve the same level of pollution control, while allowing some flexibility in maximizing profit.

A tax on inputs is one frequently cited incentive measure. In this study, alternative policies to reduce non‐point emissions from agriculture on the Columbia Plateau of Washington, Oregon and Idaho are evaluated. The environmental efficiency and effects on profits by reduction of nitrogen from fertilizer under command and control regulation and tax incentives are compared. Copyright © 2005 John Wiley & Sons, Ltd.
Considering spatial distribution and deposition of sediment in lumped and semi‐distributed models
Authors: Lenhart Thomas , Van Rompaey Anton , Steegen An , Fohrer Nicola , Frede Hans‐Georg , Govers Gerard
Published: February 2005

The goal of this paper is to test a new semi‐lumped sediment delivery concept to consider deposition. With this method, the distance between sediment source and river channel is taken into account. It is based on the assumption that sediment delivery rates (SDR‐values) are related to the length of the flow path of the sediment from source area to channel. For each subwatershed an average weighted distance to the river channel can be calculated whereby cells with little or no soil erosion have a high weight.

The procedure was implemented in SWAT‐G (Soil and Water Assessment Tool) and calibrated and validated for two watersheds in Belgium and Germany. The results point out that the proposed method is a significant improvement of the sediment routine compared to existing lumped equations such as the MUSLE. Copyright © 2005 John Wiley & Sons, Ltd.
Modelling the water balance with SWAT as part of the land use impact evaluation in a life cycle study of CO2 emission reduction scenarios
Authors: Heuvelmans Griet , Garcia‐Qujano Juan F. , Muys Bart , Feyen Jan , Coppin Pol
Published: February 2005

Life cycle assessment (LCA) is an ISO standardized method designed to evaluate the impact of human activities on the environment using objective and measurable indicators. To be effective an LCA analysis should be cost‐efficient in data gathering and the methods used for calculating the impact categories ought to be universally applicable. The land use impact category of an LCA deals with impacts of land occupation and land use change on water balance, soil and vegetation. This paper proposes to use a modelling approach to generate indicators for the land use impact of CO2 emission reduction projects on the ecosystem water balance. The rate variables of the water balance selected to describe the land use impacts are evapotranspiration, surface runoff, discharge, groundwater recharge and soil loss through water erosion. They are simulated making use of the SWAT model.

The paper describes the application of the proposed methodology for two locations with different site characteristics and land use patterns. Special attention was paid to aspects of data availability and reliability. Comparison of the simulation results with literature data revealed that SWAT provides reasonable results, which can be used for assessing the land use impact in LCA. The sensitivity analysis indicated low dependency of the model output to minor and moderate changes in model input, with the exception of changes in precipitation and leaf area index (LAI). The study also indicated that the land use library in SWAT needs further development to become universally applicable for LCA purposes. A scenario analysis allowed us to predict the impact of land occupation on the hydrology and erosion of both study areas. Finally, the LCA indicators giving the impact on the water balance per functional unit were calculated by expressing the SWAT outputs per kilogram of CO2 emission reduction. Copyright © 2005 John Wiley & Sons, Ltd.
Modelling streamflow from two small South African experimental catchments using the SWAT model
Authors: Govender M. , Everson C. S.
Published: February 2005

Increasing demand for timber products results in the expansion of commercial afforestation in South Africa. The conversion of indigenous seasonally dormant grassland to evergreen forests results in increased transpiration and ultimately a reduction in catchment runoff, creating a negative impact on the country's scarce water supplies. In order to assist managers in the decision‐making processes it is important to be able to accurately assess and predict hydrological processes, and the impact that land use change will have on water resources. The Soil and Water Assessment Tool (SWAT) provides a means of performing these assessments. One of the key strengths of the SWAT model lies in its ability to model the relative impacts of changes in management practices, climate and vegetation on water quantity and quality.

The aim of this study was to determine if the SWAT model could reasonably simulate hydrological processes in daily time steps from two small South African catchments. To verify the SWAT model a grassland (C VIgrass) and Pinus patula afforested catchment (C IIpine) were selected from the Cathedral Peak hydrological research station in the KwaZulu Natal Drakensberg mountains. These catchments were chosen because of the availability of detailed hydrological records and suitable land use.

Observed and simulated streamflow for C VIgrass and C IIpine were compared. When model fits of observed and simulated streamflow for C VIgrass were acceptable, this parameter set was then used in the configuration of C IIpine. Results show that the model performs well for C VIgrass with reasonable agreement between modelled and observed data (R2 = 0·68). Comparisons for C IIpine show a total oversimulation of streamflow for the period 1950 to 1965, with deviations between observed and modelled data increasing from 1959 to 1965, due to the model not accounting for the increase in ET brought about by the maturing pine plantation. Copyright © 2005 John Wiley & Sons, Ltd.
Advances in the application of the SWAT model for water resources management
Authors: Jayakrishnan R. , Srinivasan R. , Santhi C. , Arnold J. G.
Published: February 2005

Developments in computer technology have revolutionized the study of hydrologic systems and water resources management. Several computer‐based hydrologic/water quality models have been developed for applications in hydrologic modelling and water resources studies. Distributed parameter models, necessary for basin‐scale studies, have large input data requirements. Geographic information systems (GIS) and model–GIS interfaces aid the efficient creation of input data files required by such models. One such model available for the water resources professional is the Soil and Water Assessment Tool (SWAT), a distributed parameter model developed by the United States Department of Agriculture. This paper describes some recent advances made in the application of SWAT and the SWAT–GIS interface for water resources management. Four case studies are presented. The Hydrologic Unit Model for the United States (HUMUS) project used SWAT to conduct a national‐scale analysis of the effect of management scenarios on water quantity and quality. Integration of the SWAT model with rainfall data available from the WSR‐88D radar network helps us to incorporate the spatial variability of rainfall into the modelling process. This study demonstrates the usefulness of radar rainfall data in distributed hydrologic studies and the potential of SWAT for application in flood analysis and prediction. A hydrologic modelling study of the Sondu river basin in Kenya using SWAT indicates the potential for application of the model in African watersheds and points to the need for development of better model input data sets in Africa, which are critical for detailed water resources studies. The application of SWAT for water quality analysis in the Bosque river basin, Texas demonstrates the strength of the model for analysing different management scenarios to minimize point and non‐point pollution, and its potential for application in total maximum daily load (TMDL) studies. Copyright © 2005 John Wiley & Sons, Ltd.
Transactivation of hsp70‐1/2 in geldanamycin‐treated human non‐small cell lung cancer H460 cells: Involvement of intracellular calcium and protein kinase C
Authors: Shu Chih‐Wen , Cheng Nai‐Lin , Chang Whei‐meih , Tseng Tzu‐Ling , Lai Yiu‐Kay
Published: February 2005

Geldanamycin is an antitumor drug that binds HSP90 and induces a wide range of heat shock proteins, including HSP70s. In this study we report that the induction of HSP70s is dose‐dependent in geldanamycin‐treated human non‐small cell lung cancer H460 cells. Analysis of the induction of HSP70s specific isoform using LC‐ESI‐MS/MS analysis and Northern blotting showed that HSP70‐1/2 are the major inducible forms under geldanamycin treatment. Transactivation of hsp70‐1/2 was determined by electrophoretic mobility‐shift assay using heat shock element (HSE) as a probe. The signaling pathway mediators involved in hsp70‐1/2 transactivation were screened by the kinase inhibitor scanning technique. Pretreatment with serine/threonine protein kinase inhibitors H7 or H8 blocked geldanamycin‐induced HSP70‐1/2, whereas protein kinase A inhibitor HA1004, protein kinase G inhibitor KT5823, and myosin light chain kinase inhibitor ML‐7 had no effect. Furthermore, the protein kinase C (PKC)‐specific inhibitor Ro‐31‐8425 and the Ca2+‐dependent PKC inhibitor Gö‐6976 diminished geldanamycin‐induced HSP70‐1/2, suggesting an involvement of the PKC in the process. In addition, geldanamycin treatment causes a transient increase of intracellular Ca2+. Chelating intracellular Ca2+ with BAPTA‐AM or depletion of intracellular Ca2+ store with A23187 or thapsigargin significantly decreased geldanamycin‐transactivated HSP70‐1/2 expression. Taken together, our results demonstrate that geldanamycin‐induced specific HSP70‐1/2 isoforms expression in H460 cells through signaling pathway mediated by Ca2+ and PKC. © 2005 Wiley‐Liss, Inc.
Replication‐coupled modulation of early replicating chromatin domains detected by anti‐actin antibody
Authors: Fidlerová Helena , Mašata Martin , Malínský Jan , Fialová Markéta , Cvac̆ková Zuzana , Louz̆ecká Alena , Koberna Karel , Berezney Ronald , Ras̆ka Ivan
Published: February 2005

Evidence is presented for the reversible, cold‐dependent immunofluorescence detection of the epitope (hereafter referred to as epiC), recognized by a monoclonal anti‐actin antibody in diploid human fibroblast cell nuclei and mitotic chromosomes. The nuclear/chromosomal epiC was detected in a cell cycle window beginning in early S phase and extending through S phase, G2 phase, mitosis until early G1 phase of the subsequent daughter cells. A small but significant level of co‐localization was measured between the nuclear epiC and active sites of DNA replication in early S phase. The level of co‐localization was strikingly enhanced beginning approximately 1 h after the initial labeling of early S phase replicating chromatin domains. In contrast, epiC did not co‐localize with late S phase replicated chromatin either during DNA replication or at any other time in the cell cycle. We propose a replication‐coupled modulation of early S phase replicated chromatin domains that is detected by the chromatin epiC positivity, persists on the chromatin domains from early S until early G1 of the next cell generation, and may be involved in the regulation and/or coordination of replicational and transcriptional processes during the cell cycle. Further studies will be required to resolve the possible role of nuclear actin in this modulation process. J. Cell. Biochem. 94: 899–916, 2005. © 2005 Wiley‐Liss, Inc.
1α,25‐dihydroxyvitamin D3 stimulates steroid sulphatase activity in HL60 and NB4 acute myeloid leukaemia cell lines by different receptor‐mediated mechanisms
Authors: Hughes Philip J. , Steinmeyer Andreas , Chandraratna Roshantha A.S. , Brown Geoffrey
Published: February 2005

Steroid sulphatase is a key enzyme in the biosynthesis of bioactive estrogens and androgens from highly abundant inactive circulating sulphated steroid precursors. Little is known about how the expression/activity of this enzyme is regulated. In this article, we show that of 1α,25(OH)2D3 stimulates an increase steroid sulphatase activity in the HL60 myeloid leukaemic cell line that is inhibited by a specific nuclear VDR (VDRnuc) antagonist and unaffected by plasma membrane‐associated vitamin D receptor (VDRmem) agonists and antagonists. 1α,25(OH)2D3‐mediated up‐regulation of steroid sulphatase activity in HL60 cells was augmented by RXR agonists, blocked by RXR‐specific antagonists, and RAR specific agonists and antagonists had no effect. In contrast, the 1α,25(OH)2D3‐mediated up‐regulation of steroid sulphatase activity in the NB4 myeloid leukaemic cell line was unaffected by the specific VDRnuc and RXR antagonists, but was blocked by a VDRmem‐specific antagonist and was increased by VDRmem‐specific agonists. The findings reveal that VDRnuc‐RXR‐heterodimers play a key role in the 1α,25(OH)2D3‐mediated up‐regulation of steroid sulphatase activity in HL60 cells. However, in NB4 cells, VDRnuc‐derived signals do not play an obligatory role, and non‐genomic VDRmem‐derived signals are important. © 2005 Wiley‐Liss, Inc.
Phosphorylated osteopontin promotes migration of human choriocarcinoma cells via a p70 S6 kinase‐dependent pathway
Authors: Al‐Shami Rania , Sorensen Esben S. , Ek‐Rylander Barbro , Andersson Göran , Carson Daniel D. , Farach‐Carson Mary C.
Published: February 2005

This study examined the role of osteopontin (OPN), a phosphorylated secreted glycoprotein, in the promotion of trophoblastic cell migration, an early event in the embryo implantation process. Three human choriocarcinoma cell lines, namely JAR, BeWo, and JEG‐3, were treated with variants of OPN differing in the extent of phosphorylation following sequential dephosphorylation with tartrate‐resistant acid phosphatase (TRAP), and their migratory response was measured. The highly phosphorylated human milk form of OPN (OPN‐1) strongly triggered migration in all three cell lines, whereas the less phosphorylated variants, OPN‐2a and OPN‐2b, failed to stimulate migration. JAR cell migration in response to OPN‐1 was accompanied by a rapid rearrangement of actin filaments to the cellular membrane. Using broad spectrum protein kinase profiling, we identified p70 S6 kinase as a major signal transduction pathway activated by OPN‐1 during the migratory response in JAR cells. Activation was blocked completely by rapamycin and LY294002, thus demonstrating that OPN‐1‐stimulated migration occurs through mTOR and PI3K pathways, respectively. Conversely, PD98059 did not affect the activation of p70 S6 kinase by OPN‐1, therefore, this response does not involve the Ras/ MAPK signaling cascade. Together, these data show that the highly phosphorylated human OPN‐1 can stimulate trophoblastic cell migration and provides evidence for the involvement of the PI3K/mTOR/p70 S6 kinase pathway in the JAR cells response. Because both OPN and TRAP are expressed in the uterus during early pregnancy, it is conceivable that extracellular phosphatases such as TRAP may modify OPN charge state and thus modulate cell migration. © 2005 Wiley‐Liss, Inc.
C‐terminal region of Bfl‐1 induces cell death that accompanies caspase activation when fused with GFP
Authors: Yang Wan Seok , Ko Jae‐Kyun , Park Sue‐O , Choi Hye‐Young , Kim Yong‐Nyun , Kim Chul‐Woo
Published: February 2005

Previously, we reported that anti‐apoptotic Bfl‐1 is converted to a pro‐apoptotic protein following fusion at its N‐terminus with green fluorescent protein (GFP) (GFP‐Bfl‐1). In this study, we performed a Bfl‐1 deletion study in order to elucidate the underlying mechanism of GFP‐Bfl‐1‐induced cell death. We found that the Bcl‐2 homology (BH) domains in Bfl‐1 are dispensable with respect to cell death and that GFP fusion with the 29 amino acids of the C‐terminal region of Bfl‐1 (GFP‐BC) is sufficient to induce cell death. Moreover, when BC was fused with other tagging partners like GST or MBP, little cell death was observed, implying that the GFP region is as important as the BC region for GFP‐BC‐induced cell death. Further deletion analysis defined a region of GFP as a determinant of GFP‐BC‐induced cell death. Confocal microscopic analysis showed that GFP‐chimeras containing the BC region of Bfl‐1 are located mainly in mitochondria. The GFP‐BC‐induced cell death accompanied cellular caspase activation, and treatment with the pan‐caspase inhibitor, Boc‐D‐FMK, partially inhibited GFP‐BC‐induced cell death. However, the over‐expression of anti‐apoptotic molecules, such as Bcl‐xL and CrmA, did not block GFP‐BC‐induced cell death. In summary, GFP‐BC induces cell death with caspase activation through mitochondria dependent process. © 2005 Wiley‐Liss, Inc.
Inhibition of prolidase activity by nickel causes decreased growth of proline auxotrophic CHO cells
Authors: Miltyk Wojciech , Surazynski Arkadiusz , Kasprzak Kazimierz S. , Fivash Matthew J. , Buzard Gregory S. , Phang James M.
Published: February 2005

Occupational exposure to nickel has been epidemiologically linked to increased cancer risk in the respiratory tract. Nickel‐induced cell transformation is associated with both genotoxic and epigenetic mechanisms that are poorly understood. Prolidase [E.C.3.4.13.9] is a cytosolic Mn(II)‐activated metalloproteinase that specifically hydrolyzes imidodipeptides with C‐terminal proline or hydroxyproline and plays an important role in the recycling of proline for protein synthesis and cell growth. Prolidase also provides free proline as substrate for proline oxidase, whose gene is activated by p53 during apoptosis. The inhibition of prolidase activity by nickel has not yet been studied. We first showed that Ni(II) chloride specifically inhibited prolidase activity in CHO‐K1 cells in situ. This interpretation was possible because CHO‐K1 cells are proline auxotrophs requiring added free proline or proline released from added Gly‐Pro by prolidase. In a dose‐dependent fashion, Ni(II) inhibited growth on Gly‐Pro but did not inhibit growth on proline, thereby showing inhibition of prolidase in situ in the absence of nonspecific toxicity. Studies using cell‐free extracts showed that Ni(II) inhibited prolidase activity when present during prolidase activation with Mn(II) or during incubation with Gly‐Pro. In kinetic studies, we found that Ni(II) inhibition of prolidase varied with respect to Mn(II) concentration. Analysis of these data suggested that increasing concentrations of Mn(II) stabilized the enzyme protein against Ni(II) inhibition. Because prolidase is an important enzyme in collagen metabolism, inhibition of the enzyme activity by nickel could alter the metabolism of collagen and other matrix proteins, and thereby alter cell–matrix and cell–cell interactions involved in gene expression, genomic stability, cellular differentiation, and cell proliferation. Published 2005 Wiley‐Liss, Inc.
Establishment of an immortalized PARP‐1−/− murine endothelial cell line: A new tool to study PARP‐1 mediated endothelial cell dysfunction
Authors: Carrillo Ana , Monreal Yolanda , Ramirez Pablo , Suarez Eduardo , Parrilla Pascual , Menissier‐de Murcia Josiane , de Murcia Gilbert , Alvarez‐Vallina Luis , Yélamos José
Published: February 2005

Poly(ADP‐ribose) polymerase‐1 (PARP‐1) plays a critical role in endothelial cell dysfunction associated with various pathophysiological conditions. To elucidate PARP‐1 pathways involved in endothelial cell dysfunction, it is essential to establish “in vitro” experimental models using isolated endothelial cells. So far, two approaches have been used: primary endothelial cells from PARP‐1−/− mice which have a limited life‐span, being a major handicap if large quantities of cells are required; and pharmacological inhibition of PARP in PARP‐1+/+ endothelial cell lines, which is not specific for PARP‐1 and would have biological effects different that genetic inhibition. To overcome these limitations, we have established an immortalized PARP‐1−/− endothelial cell line (HYKO6) by transfection of primary cells with a plasmid containing the SV40 genome and selected on the basis of morphological and phenotypical features. The HYKO6 cell line exhibited endothelial characteristics, such as constitutive expression of CD105, CD31, ICAM‐2, VCAM‐1, and von Willebrand factor and formation of capillary‐like structures (CLS) on Matrigel surface. However, expression of ICAM‐1 antigen is lost in the HYKO6 cells. After TNF‐α treatment, HYKO6 cells exhibited increased expression of E‐selectin and VCAM‐1. Likewise, NF‐κB‐dependent transcriptional activation was increased in the HYKO6 cell line in response to TNF‐α at a level similar to that found for primary PARP‐1−/− cells. This cell line should provide, for the first time, a valuable tool to study PARP‐1 pathways in endothelial cell dysfunction. © 2005 Wiley‐Liss, Inc.
mRNA expression of AMPA receptors and AMPA receptor binding proteins in the cerebral cortex of elderly schizophrenics
Authors: Dracheva Stella , McGurk Susan R. , Haroutunian Vahram
Published: February 2005

L‐α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) receptors (AMPARs) mediate the majority of the fast excitatory transmission in the CNS. To determine whether gene expression of AMPARs and/or AMPAR binding proteins, which control response/sensitivity of AMPAR‐bearing neurons to glutamate, are altered in schizophrenia, mRNA expression and abundance of AMPAR subunits (GluR1–4) and several AMPAR binding proteins (SAP97, PICK1, GRIP, ABP) were measured in the dorsolateral prefrontal cortex (DLPFC) and the occipital cortex of elderly schizophrenia patients (n = 36) and matched normal controls (n = 26) by quantitative real‐time PCR. The mRNA expression of GluR1, GluR4, and GRIP in the DLPFC and expression of the GluR4, GRIP, and ABP in the occipital cortex were significantly elevated in schizophrenics. GluR1 and ABP mRNA expression in the occipital cortex and GluR2, GluR3, SAP97, and PICK1 expression in either cortical area were not significantly altered. The data also demonstrated significant differences in the abundances of mRNAs encoding GluR1–4 subunits (GluR2 > GluR3 > GluR1 > GluR4) and of AMPAR binding proteins (SAP97 > PICK1 > GRIP > ABP) in both diagnostic groups. GluR2 (58–64%) and GluR3 (24–29%) were the major components of the AMPAR mRNA in both cortical areas, implying that the major AMPAR complexes in the human cortex are probably those containing GluR2 and GluR3 subunits. Small but significant differences in the amounts of GluR2, GluR3, and GRIP mRNAs were detected between the two cortical areas: more GluR3 and GRIP but less GluR2 were detected in the DLPFC than in the occipital cortex. © 2005 Wiley‐Liss, Inc.
2‐Naphthol‐containing β‐cyclodextrin–epichlorohydrin copolymers: synthesis, characterization and fluorescence studies
Authors: Zohrehvand Shiva , Evans Christopher H
Published: February 2005

Fluorescent 2‐naphthol (NOH)‐containing β‐cyclodextrin (β‐CD)–epichlorohydrin (EP) copolymers were synthesized. Polymerization was confirmed through viscosity and FT‐IR spectroscopic measurements. Under certain conditions, the copolymers were water‐soluble (molar ratio of EP/β‐CD <22:1), while under other conditions water‐insoluble gels were formed (EP/β‐CD ≥ 22:1). Increase of the EP content to EP/β‐CD ≤ 39:1 increased the fluorescence intensity of the copolymer and shifted the emission maximum from 422 nm toward 352 nm (measured at pH ≥ 12). Further increases in the EP content resulted in a slight decrease in the fluorescence intensity. The fluorescence properties of our system at EP/β‐CD < 22 were sensitive to pH variation, while at EP/β‐CD ≥ 22 no pH effect was observed. These variations can be explained in terms of the exposure of the fluorophore to solvent in soluble versus insoluble polymers, as well as changes in the mode of association (host–guest complexation, trapping within the polymer network, covalent bonding, etc) of NOH with the polymers. Crystallographic studies on a single crystal grown in the absence of EP, but under basic conditions, suggest that host–guest complexation is not an important mode for NOH incorporation. Copyright © 2005 Society of Chemical Industry
Fast crystallization of poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) with talc and boron nitride as nucleating agents
Authors: Kai Weihua , He Yong , Inoue Yoshio
Published: February 2005

The crystallization behavior of poly(3‐hydroxybutyrate) (PHB) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) induced by two kinds of nucleating agents, boron nitride (BN) and talc, was investigated by differential scanning calorimetry, polarized optical microscopy and X‐ray diffraction. Both BN and talc have good nucleating ability in the crystallization of PHB and PHBV. From these results, combined with molecular weight measurement by gel permeation chromatography, the mechanism of nucleation by BN and talc in the crystallization of PHB and PHBV has been proposed. BN acts as a nucleating agent itself and initiates nucleation in the crystallization of PHB and PHBV. Talc acts in a different way. It reacts as a chemical reagent with the molten chains of PHB/PHBV, while the reaction product acts as the true nucleating agent, which lowers the crystallization barriers of PHB and PHBV. 1H NMR spectroscopy provides evidence for the reaction between PHB and talc and supports the proposed nucleation mechanism. Copyright © 2005 Society of Chemical Industry
Immobilization and activation of vanadium(III) and titanium(III) single‐site catalysts for ethylene polymerization using MgCl2‐based supports
Authors: Severn John R , Duchateau Robbert , Chadwick John C
Published: February 2005

Significant increases in the activity of vanadium(III) amidinate catalysts for ethylene polymerization have been obtained by immobilization on a MgCl2‐based support prepared by reaction of AlEt3 with a MgCl2/ethanol adduct. Catalyst immobilization and activation on this type of support prevents the rapid decay in activity observed under homogeneous polymerization conditions with unsupported catalysts. Stable polymerization activity is also observed with analogous titanium(III) complexes. Polyethylene with narrow molecular weight distribution and spherical particle morphology is obtained without reactor fouling. Copyright © 2005 Society of Chemical Industry
Synthesis and monomer reactivity ratio of cobalt‐containing hybrid polysilanes
Authors: Si Tae Sung , Koo Sang Man
Published: February 2005

Dichloromethylsilylcobaltcarbonyl (DCMSC) was synthesized by the reaction of dichloromethylsilane (DCMS) with dicobaltoctacarbonyl (DCOC) and used to prepare metal‐containing polysilanes. Copolymers of DCMSC with dichlorodimethyl‐ (DCDMS), dichlorodiethyl‐ (DCDES), dichloromethylphenyl‐ (DCMPS) silane were obtained using reductive coupling polymerization. The molecular weight of the copolymers increased regularly in the initial stage of the reaction but approached equilibrium values as the reaction proceeded. Depending on the monomer reactivity ratios, copolymers 2, 3 and 4 could have either alternating or block‐like copolymer structures. Increasing amounts of carbons in the side‐chain of the copolymers leads to block‐like composition. Copyright © 2005 Society of Chemical Industry
Molecular orientation behavior of poly(vinyl chloride) as influenced by the nanoparticles and plasticizer during uniaxial film stretching in the rubbery stage
Authors: Yalcin Baris , Cakmak Miko
Published: February 2005

The structural evolution during uniaxial stretching of poly(vinyl chloride) films was studied using our real time spectral birefringence stretching machine. The effect of clay loading and the amount of plasticizer as well as the rate effects on the birefringence development and true mechanical response are presented with a final model summarizing the molecular phenomena during stretching. Mechano‐optical studies revealed that birefringence correlated with mechanical response (stress, strain, work) nonlinearly. This was primarily attributed to the preexisting strong network of largely amorphous chains connected via small crystallites that act as physical crosslinking points. These crystallites are not easily destroyed during the high‐speed stretching process as evidenced from the birefringence–true strain curves along with the X‐ray crystallinity measurements. At high speeds, the amorphous chains do not have enough time to relax and hence attain higher orientation levels. The crystallites, however, orient more efficiently when stretched at slow speeds. Apparently, some relaxation of the surrounding amorphous chains helps rotate the crystallites in the stretching direction. Overall birefringence is higher at high stretching speeds for a given true strain value. When the nanoparticles are incorporated, the orientation levels are increased significantly for both the crystalline and amorphous phases. Nanoplatelets increase the continuity of the network because they have strong interaction with the amorphous chains and/or crystallites. This in turn helps transfer the local stresses to the attached chains and increase the orientation levels of the chains. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 724–742, 2005