bluuebunny/crossref_metadata_2025 huggingface dataset:
The Discovery of Novel Protein Kinase Inhibitors by Using Fragment‐Based High‐Throughput X‐ray Crystallography
Authors: Gill Adrian , Cleasby Anne , Jhoti Harren
Published: February 2005

This article describes the application of a high‐throughput X‐ray crystallographic fragment‐based screening methodology to identify low‐molecular‐weight leads for structure‐based optimisation into protein kinase inhibitors. The identification of two novel p38α MAP kinase inhibitors (with IC50=65 and 150 nM) starting from low‐molecular‐weight fragments is described.
Octyl‐Decorated Fréchet‐Type Dendrons: A General Motif for Visualisation of Static and Dynamic Behaviour Using Scanning Tunnelling Microscopy?
Authors: Merz Leo , Güntherodt H.‐J. , Scherer Lukas J. , Constable Edwin C. , Housecroft Catherine E. , Neuburger Markus , Hermann B. A.
Published: February 2005

A detailed STM study of monolayers of 3,5‐bis[(3,5‐bisoctyloxyphenyl)methyloxy]benzaldehyde and 3,5‐bis[(3,5‐bisoctyloxyphenyl)methyloxy]benzyl alcohol adsorbed on graphite is presented. Very highly resolved scanning tunnelling microscopy images are observed at room temperature in air allowing the analysis of the conformation of the adsorbed molecules. These long‐chain alkyl‐decorated Fréchet‐type dendrons are a powerful assembly motif and initially form a pattern based on trimeric units, assembled into hexagonal host structures with a pseudo‐unit cell of seven molecules, one of which remains highly mobile. Over time, the supramolecular ordering changes from a trimeric into a dimeric pattern. The chirality arising from the adsorption onto a surface of the dendrons is discussed.
N‐Fused Pentaphyrins and Their Rhodium Complexes: Oxidation‐Induced Rhodium Rearrangement
Authors: Mori Shigeki , Shin Ji‐Young , Shimizu Soji , Ishikawa Fumiaki , Furuta Hiroyuki , Osuka Atsuhiro
Published: February 2005

meso‐Aryl‐substituted pentaphyrins were isolated in the modified Rothemund–Lindsey porphyrin synthesis as a 22‐π‐electron N‐fused pentaphyrin ([22]NFP5) and a 24‐π‐electron N‐fused pentaphyrin ([24]NFP5), which were reversibly interconvertible by means of two‐electron reduction with NaBH4 or two‐electron oxidation with dichlorodicyanobenzoquinone (DDQ). Judging from 1H NMR data, [22]NFP5 is aromatic and possesses a diatropic ring current, while [24]NFP5 exhibits partial anti‐aromatic character. Metalation of [22]NFP5 1 with a rhodium(I) salt led to isolation of rhodium complexes 9 and 10, whose structures were unambiguously characterized by X‐ray diffraction analyses and were assigned as conjugated 24‐π and 22‐π electronic systems, respectively. In the rhodium(I) metalation of 1, the complex 9 was a major product at 20 °C, but the complex 10 became preferential at 55 °C. Upon treatment with DDQ, compound 9 was converted to 10 with an unprecedented rearrangement of the rhodium atom.
Bile acid derivatives as enantiodifferentiating host molecules in inclusion processes
Authors: Bortolini Olga , Fantin Giancarlo , Fogagnolo Marco
Published: February 2005

A review on the use of bile acids as hosts for molecular recognition and enantioresolution is presented. The optical resolution of different classes of organic derivatives, i.e., lactones, aliphatic alcohols, sulfoxides, epoxides, ketones, cyclic amides, cyclic carbonates, and sulfites, may be obtained by host–guest enantioselective inclusion complexation. The salient aspects of the enclathration process, including X‐ray diffraction results, are discussed. Chirality 17:121–130, 2005. © 2005 Wiley‐Liss, Inc.
On the Low‐Lying Excited States of sym‐Triazine‐Based Herbicides
Authors: Oliva Josep M. , Azenha M. Emilia D. G. , Burrows Hugh D. , Coimbra Rita , Seixas de Melo J. Serxio , Canle L. Moisés , Fernández M. Isabel , Santaballa J. Arturo , Serrano‐Andrés Luis
Published: February 2005

We report a joint computational and luminescence study on the low‐lying excited states of sym‐triazines, namely, 1,3,5‐triazine (1) and the ubiquitous herbicides atrazine [6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine (2)] and ametryn [6‐methylthio‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine (3)]. Geometrical structures, energetics, and transition and state properties of 1 and 2 were computed at the TD‐DFT, CASSCF, and CASPT2 levels of theory. The fluorescence and phosphorescence emission spectra, lifetimes, and fluorescence quantum yields were measured for the three compounds, and from these, the energies of the lowest excited states and their corresponding radiative rates were determined. The predictions from CASPT2 calculations are in good agreement with the experimental results obtained from the luminescence studies and allow the interpretation of different absorption and emission features.
Phase Separation of LaI3 inside Single‐Walled Carbon Nanotubes
Authors: Friedrichs Steffi , Falke Uwe , Green Malcolm L. H.
Published: February 2005

Simple binary solids can be found to adopt unprecedented structures when confined into nanometre‐sized cavities, such as the inner cylindrical bore of single‐walled carbon nanotubes (SWNT). In the case of the discussed LaIx@SWNT encapsulation composite, the LaI2 “crystal” fragment adopts the structure of bulk LaI3, with one third of the iodine positions unoccupied. A complete characterisation of the encapsulation composite was achieved using an enhanced digital restoration approach of high‐resolution transmission electron microscopy (HRTEM) images. The resulting complex exit surface wave provides information about the precise structural data of both filling material and host SWNT, establishing the SWNT's chirality and thus enabling a prediction of the composite's overall electron‐transport properties.
Probing the N(5)H Bond of the Isoalloxazine Moiety of Flavin Radicals by X‐ and W‐Band Pulsed Electron–Nuclear Double Resonance
Authors: Weber Stefan , Kay Christopher W. M. , Bacher Adelbert , Richter Gerald , Bittl Robert
Published: February 2005

An X‐ (9.7 GHz) and W‐band (94 GHz) pulsed electron–nuclear double resonance (ENDOR) study of the flavin cofactor of Escherichia coli DNA photolyase in its neutral radical form is presented. Through proton and deuteron ENDOR measurements at T=80 K, we detect and characterize the full anisotropy of the hyperfine coupling (hfc) tensor of the proton or deuteron bound to N(5) of the isoalloxazine ring. Scaling of the anisotropic proton hfc components by multiplication with the quotient of the magnetogyric ratio of a deuteron and a proton, χD/χH, reveals subtle differences compared to the respective deuteron couplings obtained by 95‐GHz deuterium ENDOR spectroscopy on an H→D buffer‐exchanged sample. These differences can be attributed to the different lengths of N(5)H and N(5)D bonds arising from the different masses of protons and deuterons. From the R−3 dependence of the dipolar hyperfine splitting, we estimated that the N(5)D bond is about 2.5 % shorter than the respective N(5)H bond. That such subtle bond‐length differences can be resolved by pulsed ENDOR spectroscopy suggests that this method may be favorably used to probe the geometry of hydrogen bonds between the H(5) of the paramagnetic flavin and the protein backbone. Such information is only obtained with difficulty by other types of spectroscopy.
Geometry Optimization and Conformational Analysis of (C60)N Clusters Using a Dynamic Lattice‐Searching Method
Authors: Cheng Longjiu , Cai Wensheng , Shao Xueguang
Published: February 2005

A newly developed unbiased global optimization method, named dynamic lattice searching (DLS), is used to locate putative global minima for all (C60)N clusters with Girifalco potential up to N=150. A simple greedy strategy is adopted for the basic frame, so DLS has a very high convergence speed and may converge at various configurations. As most structures are packed by basic tetrahedra, some sequences are defined by both configurations and the size of the basic tetrahedra. A sequence‐based conformational analysis is carried out with the defined sequences by counting the hit number over 10 000 independent DLS runs for all the cases up to N=150. It was found that the hit rate of a sequence is related to the size of the basic tetrahedra. Use of this method proved that the Leary tetrahedral sequence is dominant in a certain range of cluster sizes, although the sequence has no potential energy advantage. The calculation results are also consistent with those of annealing experiments at high temperature, both in magic numbers and height of the peaks in the mass spectrum.
A DFT Study of the Adsorption and Dissociation of CO on Fe(100): Influence of Surface Coverage on the Nature of Accessible Adsorption States
Authors: Bromfield Tracy C. , Curulla Ferré Daniel , Niemantsverdriet J. W.
Published: February 2005

In the present article, we report adsorption energies, structures, and vibrational frequencies of CO on Fe(100) for several adsorption states and at three surface coverages. We have performed a full analysis of the vibrational frequencies of CO, thus determining what structures are stable adsorption states and characterizing the transition‐state structure for CO dissociation. We have calculated the activation energy of dissociation of CO at 0.25 ML (ML=monolayers) as well as at 0.5 ML; we have studied the dissociation at 0.5 ML to quantify the destabilization effect on the CO(α3) molecules when a neighboring CO molecule dissociates. In addition, it is shown that the number and nature of likely adsorption states is coverage dependent. Evidence is presented that shows that the CO molecule adsorbs on Fe(100) at fourfold hollow sites with the molecular axis tilted away from the surface normal by 51.0°. The adsorption energy of the CO molecule is −2.54 eV and the CO stretching frequency is 1156 cm−1. This adsorption state corresponds to the α3 molecular desorption state reported in temperature programmed desorption (TPD) experiments. However, the activation energy of dissociation of CO(α3) molecules at 0.25 ML is only 1.11 eV (≈25.60 kcal mol−1) and the gain in energy is −1.17 eV; thus, the dissociation of CO is largely favored at low coverages. The activation energy of dissociation of CO at 0.5 ML is 1.18 eV (≈27.21 kcal mol−1), very similar to that calculated at 0.25 ML. However, the dissociation reaction at 0.5 ML is slightly endothermic, with a total change in energy of 0.10 eV. Consequently, molecular adsorption is stabilized with respect to CO dissociation when the CO coverage is increased from 0.25 to 0.5 ML.
Effect of DEM data resolution on SWAT output uncertainty
Authors: Chaubey I. , Cotter A. S. , Costello T. A. , Soerens T. S.
Published: February 2005

This paper describes the effect of DEM data resolution on predictions from the SWAT model. Measured hydrologic, meteorological, watershed characteristics and water quality data from Moores Creek watershed (near Lincoln, AR, USA) were used in the simulation. The effect of input data resolution was evaluated by running seven scenarios at increasing DEM grid sizes (30 × 30 m, 100 × 100 m, 150 × 150 m, 200 × 200 m, 300 × 300 m, 500 × 500 m, 1000 × 1000 m). The model was calibrated on an annual basis for flow, NO3‐N and total P using 30 × 30 m DEM data. The predicted output at the calibrated scale was used to evaluate output accuracy for the remaining input resolutions. Results of this study showed that DEM resolution affects the watershed delineation, stream network and sub‐basin classification in the SWAT model. A decrease in DEM resolution resulted in decreased stream flow and NO3‐N load predictions. However, model predicted total P did not always decrease with DEM resolution. Results of this study indicate that the choice of input DEM resolution depends on the watershed response of interest. Minimum DEM data resolution ranged from 100 to 200 m to achieve less than 10% error in SWAT output for flow, NO3‐N and TP predictions. Copyright © 2005 John Wiley & Sons, Ltd.
An analysis of high‐flow sediment event data for evaluating model performance
Authors: Benaman J. , Shoemaker C. A.
Published: February 2005

A methodology for utilizing high‐flow event data in model evaluation is presented. The methodology was applied to the Soil and Water Assessment Tool, version 2000 (SWAT) for the Cannonsville watershed, a rural, hilly watershed in northeastern USA, with a substantial winter snow pack. Thirty‐five high‐flow events that contained intensive total suspended solid sampling were selected in order to evaluate SWAT strengths and limitations. A comparison of calibrated model results to total sediment load data over 34 of the 35 events shows that the model underestimated the observed load by 29% (observed = 61 414 MT, predicted = 43 491 MT). In general, high sediment loading events (over 2000 metric tons) were underestimated. Most winter events were underestimated, likely due to limitations in SWAT for simulating erosion caused by snowmelt. In general, the model fit measured TSS concentrations better in the late summer/early fall than in other seasons. In addition, the model does not model erosion caused by flood waters eroding the flood plain. Additional analysis was performed for nine high‐flow events during the validation, but little conclusion could be drawn from so few events. The methodology can be used to evaluate the relative performance of the model's simulation of different processes and seasons (e.g., summer runoff events versus winter snowmelt events), provide guidance for expanding the model, and focus future calibration efforts towards controlling equations and/or parameters. Copyright © 2005 John Wiley & Sons, Ltd.
Modelling the hydrology of a catchment using a distributed and a semi‐distributed model
Authors: El‐Nasr Ahmed Abu , Arnold Jeffrey G. , Feyen Jan , Berlamont Jean
Published: February 2005

Various hydrological models exist that describe the phases in the hydrologic cycle either in an empirical, semi‐mechanistic or fully mechanistic way. The way and level of detail for the different processes of the hydrologic cycle that needs to be described depends on the objective, the application and the availability of data. In this study the performance of two different models, the fully distributed MIKE SHE model and the semi‐distributed SWAT model, was assessed. The aim of the comparative study was to examine if both models are equally able to describe the different phases in the hydrologic cycle of a catchment, given the availability of hydrologic data in the catchment. For the comparison, historic data of the Jeker river basin, situated in the loamy belt region of Belgium, was used. The size of the catchment is 465 km2. The landscape is rolling, the dominant land use is farmland, and the soils vary from sandy‐loam to clay‐loam. The daily data of a continuous period of 6 years were used for the calibration and validation of both models. The results were obtained by comparing the performance of the two models using a qualitative (graphical) and quantitative (statistical) assessment, such as graphical representation of the observed and simulated river discharge, performance indices, the hydrograph maxima, the baseflow minima, the total accumulated volumes and the extreme value distribution of river flow data. The analysis revealed that both models are able to simulate the hydrology of the catchment in an acceptable way. The calibration results of the two tested models, although they differ in concept and spatial distribution, are quite similar. However, the MIKE SHE model predicts slightly better the overall variation of the river flow. Copyright © 2005 John Wiley & Sons, Ltd.
SWAT2000: current capabilities and research opportunities in applied watershed modelling
Authors: Arnold J. G. , Fohrer N.
Published: February 2005

SWAT (Soil and Water Assessment Tool) is a conceptual, continuous time model that was developed in the early 1990s to assist water resource managers in assessing the impact of management and climate on water supplies and non‐point source pollution in watersheds and large river basins. SWAT is the continuation of over 30 years of model development within the US Department of Agriculture's Agricultural Research Service and was developed to ‘scale up’ past field‐scale models to large river basins. Model components include weather, hydrology, erosion/sedimentation, plant growth, nutrients, pesticides, agricultural management, stream routing and pond/reservoir routing. The latest version, SWAT2000, has several significant enhancements that include: bacteria transport routines; urban routines; Green and Ampt infiltration equation; improved weather generator; ability to read in daily solar radiation, relative humidity, wind speed and potential ET; Muskingum channel routing; and modified dormancy calculations for tropical areas. A complete set of model documentation for equations and algorithms, a user manual describing model inputs and outputs, and an ArcView interface manual are now complete for SWAT2000. The model has been recoded into Fortran 90 with a complete data dictionary, dynamic allocation of arrays and modular subroutines. Current research is focusing on bacteria, riparian zones, pothole topography, forest growth, channel downcutting and widening, and input uncertainty analysis.

The model SWAT is meanwhile used in many countries all over the world. Recent developments in European Environmental Policy, such as the adoption of the European Water Framework directive in December 2000, demand tools for integrative river basin management. The model SWAT is applicable for this purpose. It is a flexible model that can be used under a wide range of different environmental conditions, as this special issue will show. The papers compiled here are the result of the first International SWAT Conference held in August 2001 in Rauischholzhausen, Germany. More than 50 participants from 14 countries discussed their modelling experiences with the model development team from the USA. Nineteen selected papers with issues reaching from the newest developments, the evaluation of river basin management, interdisciplinary approaches for river basin management, the impact of land use change, methodical aspects and models derived from SWAT are published in this special issue. Copyright © 2005 John Wiley & Sons, Ltd.
Effect of GIS data quality on small watershed stream flow and sediment simulations
Authors: Di Luzio Mauro , Arnold Jeffrey G. , Srinivasan Raghavan
Published: February 2005

Simulations of total runoff and fine sediment yield in Goodwin Creek watershed, which covers 21·3 km2 in Mississippi, were carried out using a hydrological model‐GIS system. The system includes the recently released Soil and Water Assessment Tool (SWAT) model version 2000 and AVSWAT version 1·0, the supporting interface with ArcView GIS. Among the required GIS input, some are commonly available in the United States with multiple options and characteristics. In our study, two available digital elevation models, three land use–land cover maps and two soil maps were grouped in all possible ways to obtain 12 applied input combinations.

The objective of this study was to assess the impact of GIS input variation on the uncalibrated water runoff and sediment yield outputs and compare them with the respective observed data. The implicated issues are significant wherever multiple choices of GIS input are available. In the United States, agencies are developing TMDL (total maximum daily load) programmes at the watershed scale and are also using supporting tools along with the available GIS data. In addition, the involved water quality appraisals often include assessment of limited size watersheds, i.e. draining into a specific stream segment. This watershed, operated by the United States Department of Agriculture, Agriculture Research Service, is highly instrumented, thereby representing a severe test and a primary verification of the new system.

The GIS data had a varying impact on model results. DEM choice was critical for a realistic definition of the watershed and subwatershed boundaries and topographic input, and consequently simulated outputs. Land use–land cover maps had a significant effect on both runoff and sediment yield prediction. Soil maps showed a limited influence on model results.

While evidences and basic justifications of the results are provided, further investigations are needed to determine the influence of the input GIS data distribution on watersheds with various sizes, geomorphological and spatial settings. Copyright © 2005 John Wiley & Sons, Ltd.
Automatic model calibration
Authors: Eckhardt Klaus , Fohrer Nicola , Frede Hans‐Georg
Published: February 2005

Model calibration allows reducing parameter uncertainty and, therefore, uncertainty in simulation results. In the present study, automatic model calibration with the shuffled complex evolution algorithm is demonstrated using the example of the distributed conceptual model SWAT‐G, a derivative of the Soil and Water Assessment Tool (SWAT). The special challenge in calibrating SWAT is that it describes many physical processes and therefore is highly parameterized. Moreover, as SWAT or SWAT‐G, respectively, is a distributed model, the parameters may take on different values in different spatial subunits of a catchment model. A strategy of imposing constraints on the parameters to limit the number of independently calibrated values is outlined and applied to the model of a mesoscale low mountain range catchment. Copyright © 2005 John Wiley & Sons, Ltd.
Estimating shallow groundwater recharge in the headwaters of the Liverpool Plains using SWAT
Authors: Sun H. , Cornish P. S.
Published: February 2005

A physically based catchment model (SWAT) was used for recharge estimation in the headwaters of the Liverpool Plains in NSW, Australia. The study used water balance modelling at the catchment scale to derive parameters for long‐term recharge estimation. The derived parameters were further assessed at a subcatchment scale. Modelling results suggest that recharge occurs only in wet years, and is dominated by a few significant years or periods. The results were matched by independently observed bore data across the study area in the past 30 years. The study suggests that variations in recharge can be primarily explained by the climatic factor rather than land‐use changes. The study estimated less recharge than previous studies where point scale modelling results have been scaled up to the catchment scale. It suggests that a catchment‐based approach is needed for recharge estimation at the catchment scale. The study indicates that the current model may overestimate runoff on cracking vertosols under dry conditions where improvement is likely needed. The need for long‐term runoff and bore monitoring data to confidently establish the relationships among water balance/recharge estimation and groundwater level variation is discussed. SWAT provides an alternative to point scale modelling for evaluating recharge and its response to changes in land use and land management. Copyright © 2005 John Wiley & Sons, Ltd.
Development of effective management plan for critical subwatersheds using SWAT model
Authors: Tripathi M. P. , Panda R. K. , Raghuwanshi N. S.
Published: February 2005

The present investigation is an effort to develop an effective management plan for the identified critical subwatersheds of Nagwan watershed located in the eastern part of India using a precalibrated and validated Soil and Water Assessment Tool (SWAT) model. In all 60 combinations of various management treatments including crops (rice, maize, peanut and soybean), tillage (zero, conservation, field cultivator, mould board plough and conventional practices) and levels of fertilizer (existing, half of recommended and recommended) have been studied.

This study revealed that crops like maize, peanut and soybean could not replace rice since they resulted in higher sediment yield compared to rice. The tillage practice with mould board plough has been found to have a more appreciable impact on the sediment and nutrient losses than conventional tillage practices for the existing level of fertilizer. Sediment yield decreased in case of zero tillage, conservation tillage and field cultivator compared to conventional tillage. On the other hand, nutrient losses increased in case of zero and conservation tillage for all levels of fertilizer compared to the other tillage treatments.

In conclusion it can be stated that the sediment yield is highest in case of mould board plough followed by conventional tillage field cultivator, conservation tillage and least in zero tillage practices, whereas the nutrient losses were found to be just in the reverse order with tillage practices, indicating highest nutrient losses in mould board plough tillage practices. In view of the sediment yield and nutrient losses, the conventional tillage practice was considered to be the best as the sediment yield is less than the average soil loss and nutrient loss is within the permissible limit. Copyright © 2005 John Wiley & Sons, Ltd.
Development of the ecohydrological model SWIM for regional impact studies and vulnerability assessment
Authors: Krysanova Valentina , Hattermann Fred , Wechsung Frank
Published: February 2005

In this paper the ecohydrological model SWIM developed for regional impact assessment is presented, and examples of approaches to climate and land use change impact studies are described. SWIM is a continuous‐time semi‐distributed ecohydrological model, integrating hydrological processes, vegetation, nutrients (nitrogen and phosphorus) and sediment transport at the river basin scale. Its spatial disaggregation scheme has three levels: (1) basin, (2) sub‐basins and (3) hydrotopes within sub‐basins. The model was extensively tested and validated for hydrological processes, nitrogen dynamics, crop yield and erosion (mainly in mesoscale sub‐basins of the German part of the Elbe River basin). After appropriate validation in representative sub‐basins, the model can be applied at the regional scale for impact studies. Particular interest in the global change impact studies is given to effects of expected changes in climate and land use on hydrological processes and agro‐ecosystems, including water balance components, water quality and crop yield. This paper (a) introduces the reader to the class of process‐based ecohydrological catchment scale models, (b) introduces SWIM as one such model, and (c) presents two examples of impact studies performed with SWIM for the federal state of Brandenburg (Germany), which overlaps with the lowland part of the Elbe drainage area. The impact studies provide a better understanding of the complex interactions between climate, hydrological processes and vegetation, and improve our potential adaptation to the expected changes. Copyright © 2005 John Wiley & Sons, Ltd.
Return‐flow assessment for irrigation command in the Palleru river basin using SWAT model
Authors: Gosain A. K. , Rao Sandhya , Srinivasan R. , Reddy N. Gopal
Published: February 2005

Due to the ever‐increasing demand for water resources, the pressure on their judicious utilization is also increasing. Besides being precious, water is also a very complex commodity. The dynamic nature of weather as well as the spatial variability of landmass contribute to the dynamic behaviour of the response of the watersheds to the natural and artificial inputs of water. This requirement has led to the formulation of continuous, distributed parameter, water balance simulation models capable of providing insight into the distribution and utilization of water in a watershed. Since they mimic the natural processes prevalent in the area, they are capable of providing many answers that are normally not easily available otherwise. In the present paper one such situation has been tackled using the SWAT (Soil and Water Assessment Tool) model. The target question was to assess the return flow on account of introducing canal irrigation in a basin (Palleru river basin in the southern state of Andhra Pradesh, India). Since the return flow is dependent on many aspects such as soil characteristics, method of irrigation, etc., it is not appropriate to put a rule‐of‐thumb value on such quantities. Through modelling, the return flow has been assessed and validated. The temporal variation of such return flows has also been captured. The virgin flows from the basin, before the manmade changes in construction of reservoir and importing water for irrigation were introduced, were also computed as per the requirement of the department. In fact this has been an exercise in demonstrating the usefulness of creating such a base framework capable of helping water managers in planning and management of this very vital resource. Copyright © 2005 John Wiley & Sons, Ltd.
Assessment of the effects of land use patterns on hydrologic landscape functions: development of sustainable land use concepts for low mountain range areas
Authors: Fohrer N. , Haverkamp S. , Frede H.‐G.
Published: February 2005

Risk assessment of future land use changes with respect to their ecological impact is still an unsolved problem. The implementation of sustainable land use concepts for mesoscale catchments requires a methodology that is able to quantify the effects on the water balance of this ecosystem. Paired catchment experiments on this scale are either not feasible or too time‐consuming and expensive, and the results are usually not transferable to other regions. Thus the application of hydrological models can clarify the processes involved and support well‐balanced management decisions.

The GIS‐linked software package IOSWAT consisting of the pre‐processing tools TOPAZ, SUSAT and SWATGRASS, the ecohydrologic model SWAT‐G and the post‐processing program OUTGRASS were tested in the German Aar watershed (60 km2), which is located in a low mountain range area in the federal state of Hessen. The aim of this modelling exercise is the development of a method for land use change analysis in order to derive sustainable land use options. The impact of different average field sizes on the spatial distribution of agricultural production systems was analysed by the economic model ProLand. Spatially distributed land use scenarios for an average field size of 0·5, 0·75, 1, 2, 5, 10 and 20 ha have been provided in the form of raster maps with a resolution of 25 m × 25 m and were analysed with the IOSWAT modelling system with regard to their hydrological effect. In general, the model predicts reasonable annual trends for the water balance components of the scenarios under investigation. However, the absolute changes due to deforestation, augmentation of grassland and field crops remain much smaller than expected. The peak flow rate is especially affected by the changes in land use. The strongest impact can be observed in the spatial pattern of water balance components within the catchment. Copyright © 2005 John Wiley & Sons, Ltd.
Runoff simulations on the macroscale with the ecohydrological model SWIM in the Elbe catchment–validation and uncertainty analysis
Authors: Hattermann F. F. , Wattenbach M. , Krysanova V. , Wechsung F.
Published: February 2005

This study presents an example where the hydrological processes of the ecohydrological model SWIM (Soil and Water Integrated Model) are thoroughly analysed. The model integrates hydrology, vegetation, erosion and nutrient dynamics. It is process‐based and has to be calibrated. The hydrological validation of the model is of prime importance, because all other ecological processes are related to the water cycle. On the other hand, these ecological processes influence the water cycle in turn, and therefore they were considered in the modelling process and in the sensitivity and uncertainty analysis.

The validation was multi‐scale, multi‐site and multi‐criteria: the validation strategy followed a bottom‐up approach in which the model was firstly calibrated for 12 mesoscale sub‐basins, covering the main subregions of the German part of the Elbe basin, and the information gained from the mesoscale was then used to validate the model for the entire macroscale basin. Special attention was paid to the use of spatial information (maps of water table) to validate the model in addition to commonly used observations of water discharge at the basin outlet. One main result was that investigations in smaller catchments have to accompany macroscale model applications in order to understand the dominant hydrological processes in the different areas of the entire basin and at different scales.

The validation was carried out in the German part of the Elbe river basin (∼80 258 km2). It is representative of semi‐humid landscapes in Central Europe, where water availability during the summer season is a limiting factor for plant growth and crop yield. Copyright © 2005 John Wiley & Sons, Ltd.
Assessment of the effect of land use patterns on hydrologic landscape functions: a comprehensive GIS‐based tool to minimize model uncertainty resulting from spatial aggregation
Authors: Haverkamp S. , Fohrer N. , Frede H.‐G.
Published: February 2005

It is a common technique to predict hydrologic effects of land use changes by simulation models. On the scale of watersheds, hydrologic models comprise different approaches for many hydrologic components. One important source of model uncertainty results from errors of measured input data and their spatial aggregation. Whereas simulations on the basis of measured land use can be validated by measuring resulting hydrologic components, model uncertainty on land use scenarios cannot be quantified because of their virtuality. An entropy‐based algorithm is proposed and validated, which should serve for the identification of an appropriate level of spatial aggregation. This technique is statistically based and applicable for common methods of subwatershed and hydrologic response unit (HRU) delineation. The main criterion of this algorithm is the heterogeneity of data distribution within the investigated watershed, which might vary for different land use scenarios.

For spatial output analysis of a long‐term hydrologic model, a reassignment technique of statistically distributed output values to certain grids was developed. It combines efficient model calculations for aggregated spatial areas without losing spatial output heterogeneity. This procedure enables model validation on a grid‐based resolution and serves for the identification of spatial differences of uncertainty. Besides these new approaches for spatial analysis, different common tools for data pre‐ and post‐processing were integrated into the comprising software package IOSWAT, linked to a GIS. The results of the new approaches prove them to be valid for different watersheds and hydrologic conditions. The application of the comprehensive software package is presented in Fohrer et al. (this issue). Copyright © 2005 John Wiley & Sons, Ltd.
Regulation of metastasis‐suppressive gene Nm23‐H1 on glycosyl‐transferases involved in the synthesis of sialyl Lewis antigens
Authors: Duan Ling‐Ling , Guo Peng , Zhang Ying , Chen Hui‐Li
Published: February 2005

By using reverse transcriptase‐polymerase chain reaction (RT‐PCR), the mRNA expressions of three families of glycosyltransferases involved in the synthesis of sialyl Lewis antigens were determined in H7721 human hepatocarcinoma cell line before and after the transfection of metastasis‐suppressive gene nm23‐H1. These glycosyltransferases included α1,3fucosyltransferase (α1,3FucT)‐III, ‐IV, ‐VI, ‐VII, and ‐IX, α2,3‐sialyltransferase (ST3Gal)‐I, ‐II, ‐III, and ‐IV as well as O‐glycan core 2 β1,6 N‐acetylglucosaminyltransferase (C2GnT)‐I and ‐II. In mock cells transfected with the vector, the expression‐order of α1,3FucTs was IV > VI > III > VII > IX, that of ST3Gals was IV > I > II > III, and that of C2GnT was I > II. Nm23‐H1 downregulated the mRNA expressions of all five subtypes of α1,3FucT and ‐I, ‐III, ‐IV subtypes of ST3Gal, but not ST3Gal‐II and C2GnT‐I, II. On the other hand, the expressions of cell surface sialyl Lewis X (SLex) and α2,3 sialyl residues were decreased on nm23‐H1 transfected cells as detected with monoclonal antibody of SLex and enzyme‐labeled lectins, respectively. Since SLex was reported to be a metastasis‐associated glycan structure, the reduced expressions of SLex and some enzymes related to its synthesis may be one of the mechanisms to explain the metastasis‐suppressive effect of nm23‐H1. J. Cell. Biochem. 94: 1248–1257, 2005. © 2005 Wiley‐Liss, Inc.
Transcriptional enhancers: Intelligent enhanceosomes or flexible billboards?
Authors: Arnosti David N. , Kulkarni Meghana M.
Published: February 2005

In higher eukaryotes, transcriptional enhancers play critical roles in the integration of cellular signaling information, but apart from a few well‐studied model enhancers, we lack a general picture of transcriptional information processing by most enhancers. Here we discuss recent studies that have provided fresh insights on information processing that occurs on enhancers, and propose that in addition to the highly cooperative and coordinate action of “enhanceosomes”, a less integrative, but more flexible form of information processing is mediated by information display or “billboard” enhancers. Application of these models has important ramifications not only for the biochemical analysis of transcription, but also for the wider fields of bioinformatics and evolutionary biology. J. Cell. Biochem. 94: 890–898, 2005. © 2005 Wiley‐Liss, Inc.
Modulation of Elk‐dependent‐transcription by Gene33
Authors: Keeton Adam B. , Messina Joseph L.
Published: February 2005

Gene33 is a cytoplasmic protein expressed in many cell types, including those of renal and hepatic origin. Its expression is regulated by a large number of mitogenic and stressful stimuli, both in cultured cells and in vivo. Gene33 protein possesses binding domains for ErbB receptors, 14‐3‐3 proteins, SH‐3 domains, and GTP bound Cdc42, suggesting that it may play a role in signal transduction. Indeed, these regions of Gene33 have been reported to modulate signaling through the ERK, JNK, and NFκB pathways. In the present work, epitope‐tagged full‐length and truncation mutants, as well as wild‐type Gene33, were overexpressed in 293 cells. The expression of these proteins was compared to the level of endogenous Gene33 by Western blot using a newly developed polyclonal antibody. As proxies for activity of the ERK and JNK pathways, Elk‐ and c‐Jun‐dependent transcription were measured by a luciferase reporter gene. Moderate expression levels of full‐length Gene33 caused a twofold increase in Elk‐dependent transcription, while at higher levels, c‐Jun‐dependent transcription was partially inhibited. The C‐terminal half of Gene33 significantly increased both Elk‐ and c‐Jun‐dependent transcription when expressed at approximately threefold above control levels. This effect on Elk‐dependent transcription was lost at higher levels of Gene33 expression. In contrast, higher levels of the C‐terminal half of Gene33 caused a progressively greater effect on c‐Jun‐dependent transcription. These findings suggest that Gene33 may increase ERK activity, and that the C‐terminal half of Gene33 may act less specifically in the absence of the N‐terminal half, inducing JNK activity. © 2005 Wiley‐Liss, Inc.
Preparation and characterization of spongy cryogels of poly(vinyl alcohol)–casein system: water sorption and blood compatibility study
Authors: Bajpai Anil , Saini Rajesh
Published: February 2005

Polyvinyl alcohol (PVA) and casein are biocompatible and biodegradable macromolecules, which have been widely applied in biomedical fields. In this paper, novel physically crosslinked hydrogels composed of PVA and casein were prepared by repeated freezing–thawing treatment of aqueous solutions of PVA and casein and characterized by IR, differential scanning calorimetry and scanning electron microscopy techniques. The prepared so‐called ‘cryogels’ were evaluated for their water uptake, and the influences of various factors, such as their chemical architecture and the pH and temperature of the swelling bath, were investigated in terms of water sorption. The effect of salt and various simulated biological fluids on the swelling of cryogels was investigated. The in vitro biocompatibility of the prepared cryogels was also judged by methods such as protein (bovine serum albumin) adsorption, blood clot formation and percentage haemolysis measurements. Copyright © 2005 Society of Chemical Industry
Polymerization of propylene using MgCl2 (ethoxide type)/TiCl4/diether heterogeneous Ziegler–Natta catalyst
Authors: Zohuri Gholam Hossein , Kasaeian Ali Bakhash , Torabi Angagi Mahmoud , Jamjah Roghieh , Mousavian Mohammad Ali , Emami Mehersal , Ahmadjo Saied
Published: February 2005

Heterogeneous Ziegler–Natta catalyst of MgCl2 (ethoxide type)/TiCl4/diether was prepared. 2,2‐Diisobutyl‐1,3‐dimethoxy propane (DiBDMP), diether, was used as internal donor. Slurry polymerization of propylene was carried out using the catalyst in dry heptane while triethylaluminium (TEA) was used as co‐catalyst. The co‐catalyst effects, such as catalyst molar ratio, polymerization temperature, H2 pressure, external donor, triisobutylaluminium (TiBA) and monomer pressure, on the activity of the catalyst and isotacticity index (II) of the polymers obtained were studied. Rate of polymerization versus polymerization time is of a decay type with no acceleration period. There are an optimum Al/Ti molar ratio and temperature to obtain the highest activity of the catalyst. The maximum activity was obtained at 60 °C. Increasing the monomer pressure to 1 010 000 Pa linearly increased the activity of the catalyst. Addition of hydrogen to 151 500 Pa pressure increased activity of the catalyst from 2.25 to 5.45 kg polypropylene (PP) (g cat)−1 h−1 using 505 000 Pa pressure of monomer. The II decreased with increasing Al/Ti ratio, monomer pressure, hydrogen pressure and increased with increasing temperature to 60 °C, following with decrease as the temperature increases. Productivity of 11.55 kg (PP) (g cat)−1 h−1 was obtained at 1 010 000 Pa pressure of monomer and temperature of 60 °C. Addition of methyl p‐toluate (MPT) and dimethoxymethyl cyclohexyl silane (DMMCHS) as external donors decreased the activity of the catalyst sharply, while the II slightly increased. Some studies of the catalyst structure and morphology of the polymer were carried out using FTIR, X‐ray fluorescence, scanning electron microscopy and Brunauer–Emmett–Teller techniques. Copyright © 2005 Society of Chemical Industry
Rheological and mechanical properties of DGEBA‐S epoxy copolymer initiated by N‐benzylquinoxalinium hexafluoroantimonate
Authors: Park Soo‐Jin , Kang Jun‐Gil , Kwon Soo‐Han
Published: February 2005

The rheological and mechanical properties of the DGEBA‐S epoxy copolymer initiated by N‐benzylquinoxalinium hexafluoroantimonate (BQH) as a cationic latent thermal catalyst were investigated. The rheological properties of the DGEBA‐S/BQH system were investigated using a rheometer under isothermal conditions, and the mechanical properties of the casting specimens, involving flexure and impact tests, were also performed. The crosslinking activation energy and mechanical properties of the DGEBA‐S/BQH system were higher than those of the DGEBA/BQH system. This could be attributed to the introduction of sulfone groups with a polar nature to the main chain of the epoxy resins which led to a decrease of molecular motion and an improvement in the toughness of the cured epoxy copolymers. Copyright © 2005 Society of Chemical Industry
Li1.3Al0.3Ti1.7(PO4)3 filler effect on (PEO)LiClO4 solid polymer electrolyte
Authors: Wang Yan‐Jie , Pan Yi
Published: February 2005

Composite polymer electrolyte (CPE) films consisting of PEO, LiClO4, and Li1.3Al0.3Ti1.7(PO4)3 with fixed EO/Li = 8 but different relative compositions of the two lithium salts were prepared by the solution casting method. The CPE films were characterized using SEM, DSC, electrical impedance spectroscopy (EIS), and ion transference number measurement. It was found that the incorporation of LiClO4 and Li1.3Al0.3Ti1.7(PO4)3 into PEO by keeping EO/Li = 8 reduced the crystallinity of PEO from 50.34% to the range of 3.57–15.63% depending upon the relative composition of the two salts. The room temperature impedance spectra of the CPE films all exhibited a shape of depressed semicircle in the high frequency range and inclined line in the low frequency range, but the high temperature ones were mainly inclined lines. The Li+ ionic conductivity of the CPE films mildly increased and then decreased with increasing Li1.3Al0.3Ti1.7(PO4)3 content, and the maximum conductivities were obtained at Li1.3Al0.3Ti1.7(PO4)3 content of 15 wt % for all measuring temperatures, for example, 1.378 × 10−3 S/cm at 100 °C and 1.387 × 10−5 S/cm at 25 °C. The temperature dependence of the ionic conductivity of the CPE films follows the Vogel–Tamman–Fulcher (VTF) equation

The pseudo activation energies (Ea) were rather low, 0.053–0.062 eV, indicating an easy migration of Li+ in the amorphous phase dominant PEO. The pre‐exponent constant A and ion transference number tLi+ were found to have a similar variation tendency with increasing Li1.3Al0.3Ti1.7(PO4)3 content and reached their maximums also at Li1.3Al0.3Ti1.7(PO4)3 content of 15 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 743–751, 2005
Molecular dynamics simulations of human butyrylcholinesterase
Authors: Suárez Dimas , Field Martin J.
Published: February 2005

Herein, we present results from molecular dynamics (MD) simulations of the human butyrylcholinesterase (BuChE) enzyme in aqueous solution. Two configurations of the unbound form of BuChE differing in the presence or absence of a sodium ion inside the protein gorge were simulated for 10 and 5 ns, respectively. Besides complementing the structural information provided by X‐ray data, the MD simulations give insight into the structure of the native BuChE enzyme. For example, it is shown that: the nucleophilic Ser198 residue and the various binding subsites in the BuChE catalytic cavity are readily accessible from the exterior of the protein; the presence of the sodium ion dynamically explores two different binding sites in the gorge leading to the active site and stabilizes the productive conformation of the Glu325/His438/Ser198 catalytic triad; several long‐lived water bridges are fully integrated into the architecture of the active site; the positions of the residues at the rim of the gorge region display large deviations with respect to the crystal structure; and two side doors, constituted by residues situated at the tip of the acyl‐ and Ω‐loops, respectively, open wide enough to allow the passage of water molecules. In conclusion, we compare our theoretical results with those from previous work on mouse acetylcholinesterase and discuss their implications for substrate binding and catalysis in BuChE. Proteins 2005. © 2005 Wiley‐Liss, Inc.