bluuebunny/crossref_metadata_2025 huggingface dataset:
Rho Inhibition Induces Migration of Mesenchymal Stromal Cells
Authors: Jaganathan Bithiah Grace , Ruester Brigitte , Dressel Lars , Stein Stefan , Grez Manuel , Seifried Erhard , Henschler Reinhard
Published: May 2007

Although mesenchymal stromal cells (MSCs) are being increasingly used as cell therapeutics in clinical trials, the mechanisms that regulate their chemotactic migration behavior are incompletely understood. We aimed to better define the ability of the GTPase regulator of cytoskeletal activation, Rho, to modulate migration induction in MSCs in a transwell chemotaxis assay. We found that culture-expanded MSCs migrate poorly toward exogenous phospholipids lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) in transwell assays. Moreover, plasma-induced chemotactic migration of MSCs was even inhibited after pretreatment with LPA. LPA treatment activated intracellular Rho and increased actin stress fibers in resident MSCs. Very similar cytoskeletal changes were observed after microinjection of a cDNA encoding constitutively active RhoA (RhoAV14) in MSCs. In contrast, microinjection of cDNA encoding Rho inhibitor C3 transferase led to resolution of actin stress fibers, appearance of a looser actin meshwork, and increased numbers of cytoplasmic extensions in the MSCs. Surprisingly, in LPA-pretreated MSCs migrating toward plasma, simultaneous addition of Rho inhibitor C2I-C3 reversed LPA-induced migration suppression and led to improved migration. Moreover, addition of Rho inhibitor C2I-C3 resulted in an approximately 3- to 10-fold enhancement of chemotactic migration toward LPA, S1P, as well as platelet-derived growth factor or hepatocyte growth factor. Thus, inhibition of Rho induces rearrangement of actin cytoskeleton in MSCs and renders them susceptible to induction of migration by physiological stimuli.

Disclosure of potential conflicts of interest is found at the end of this article.
Simulating Tritium Fluxes in the Vadose Zone under Transient Saturated Conditions
Authors: Rebel Karin T. , Riha Susan J. , Karssenberg Derek , Stedinger Jery R.
Published: May 2007

A phytoremediation project was established at the U.S. Department of Energy's Savannah River Site (South Carolina) to reduce fluxes of tritium‐contaminated groundwater to surface waters. Contaminated groundwater was collected in a pond and applied by spray irrigation to a catchment of mixed forest on Atlantic Coastal Plain soils. The objectives of this research project were to simulate tritium uptake by the vegetation and to determine if subsurface lateral flow at the sand‐clay interface impacts tritium uptake by forest vegetation. To simulate water and tritium fluxes within the catchment, we developed a spatially explicit water and solute transport model. Vertical water flow was simulated within a grid using a layered capacitance model with lateral flow between cells dependent on head development and the local slope of the impeding clay layer. Tritium movement was simulated on a daily basis assuming complete mixing within a cell. The model was evaluated by comparing biweekly measurements of soil tritium activity and soil water content in 18 measurement clusters distributed across the irrigated portion of the catchment. Although lateral flow was predicted to occur locally, after 3 yr of tritium irrigation, the model predicted that lateral transfer of tritium was <70 m downslope of the irrigation area. Transient saturated conditions were observed and simulated to occur within parts of the catchment. Including the simulation of subsurface lateral flow of water and tritium under transient saturated conditions, however, did not significantly alter average tritium uptake predictions for the catchment.
Soil Vapor Extraction Performance in Layered Vadose Zone Materials
Authors: Switzer Christine , Kosson David S.
Published: May 2007

A pilot soil vapor extraction (SVE) system was installed at a small landfill within the Savannah River Site to address trichloroethylene (TCE) contamination present in the vadose zone. The SVE system has been operating since September 1999 and numerous tests have been performed on the system. A model was developed to simulate SVE at this site, incorporating the effects of contaminant behavior in a layered subsurface as well as the effects of contaminant diffusion into and out of soil aggregates. The objectives of this study were to: (i) compare the field data from the site with predictions from this mechanistic model; and (ii) establish the case for closure based on field observations and model predictions. A dense non‐aqueous‐phase liquid TCE source was discovered at the site during the course of operation. Location of this source compares well with the predicted residual source from the application of the diffusion components of the SVE model to soil gas TCE concentration rebound observations. Collectively, the field observations and the model predictions strongly support the observations that a substantial portion of the source contamination at the site has been removed by the SVE system and that the criteria for site closure have been met.
Modeling Long‐Term Plutonium Transport in the Savannah River Site Vadose Zone
Authors: Demirkanli Deniz I. , Molz Fred J. , Kaplan Daniel I. , Fjeld Robert A. , Serkiz Steven M.
Published: May 2007

Improved understanding of flow and radionuclide transport in vadose zone sediments is fundamental to future planning involving radioactive materials. To that end, long‐term experiments were conducted at the Savannah River Site (SRS), where a series of lysimeters containing sources of different Pu oxidation states were placed in the shallow subsurface and exposed to the environment for 2 to 11 yr. After the experiments, Pu activity concentrations were measured along vertical cores from the lysimeters. Plutonium distributions were anomalous in nature—transport from oxidized Pu sources was less than expected, and a small fraction of Pu from reduced sources moved more. Studies conducted with these lysimeter sediments indicated that surface‐mediated, oxidation–reduction (redox) reactions may be responsible for the anomalies. This hypothesis is tested by performing transient Pu transport simulations that include retardation and first‐order redox reactions on mineral surfaces within a steady‐state flow field. These simulations affirm the consistency of the surface‐mediated, redox hypothesis with observed Pu activity profiles below the source. Such profiles are captured well by a steady‐state, net downward flow model. The redox model explains how Pu(V/VI) sources release activity that moves downward more slowly than expected, and how Pu(III/IV) sources result in a small fraction of activity that moves downward farther than expected. The calibrated parameter values were robust and well defined throughout all simulations. Approximate retardation factors for Pu(V/VI) were 15, and for Pu(III/IV) were 10,000. For these values, ko averaged 2.4 × 10−7 h−1; kr averaged 7.1 × 10−4 h−1 (standard deviations are 1.6 × 10−7 h−1 and 1.6 × 10−4 h−1 respectively).
An Unsteady Dual Porosity Representation of Tritium Leaching from Buried Concrete Rubble
Authors: Flach G. P. , Crapse K. P. , Phifer M. A. , Collard L. B. , Koffman L. D.
Published: May 2007

Decontamination and decommissioning at the Savannah River Site near Aiken, SC, have produced on‐site disposals of low‐level solid radioactive waste in the form of concrete rubble. In the case of a former tritium extraction facility, building demolition produced a significant volume of rubble containing tritium. The contaminated debris comprises a heterogeneous mixture of coarse aggregate sizes, shapes, and internal tritium distributions. The rubble was disposed in unlined earthen trenches that were subsequently backfilled and exposed to normal infiltration. To forecast tritium flux to the water table, an unsteady dual‐porosity model was developed to describe vadose zone leaching and transport. Tritium release was assumed to be controlled by diffusion within concrete, while advective and diffusive transport occur in the surrounding backfill. Rubble size and shape variations were characterized through a combination of physical measurement and photographic image analysis. For simplicity, the characterization data were reduced to an approximately equivalent distribution of one‐dimensional slab thicknesses for representation in the dual‐porosity formulation. Tritium flux to the water table from concrete rubble was predicted to be roughly 40% of that from uniformly contaminated soil. The lower flux is a result of slow release to soil pore water and a reduced effective trench conductivity from the presence of impervious concrete. At early times, tritium release from concrete in the lower trench is depressed by downward migration of tritium from overlying material. The pattern reverses at later times, when tritium is largely exhausted in the upper trench but higher residuals occupy the lower trench.
Mycorrhizal Fungi: Highways for Water and Nutrients in Arid Soils
Authors: Allen Michael F.
Published: May 2007

Mycorrhizal fungi are well known for increasing nutrient uptake but their effects on soil physical structure and water flow are less well understood. Here I explore what we know about the physical structure of mycorrhizal external mycelia and examine how that physical structure affects plant water uptake and reverse hydraulic lift in unsaturated soils. Mycorrhizal fungi are structured such that there are linear cytoplasmic units that can extend for a meter or more. Cell membranes may be only located in hyphal tips within the plant and externally several centimeters to meters distant from the plant root. Individual hyphae form a linear surface that goes across soil pores increasing the tortuosity factor (Γ) of the pathway for water flow, thereby increasing conductivity. But hyphae are small in diameter, providing only a small surface area for that transport. Little about the reverse flows (hydraulic redistribution from plant to fungus) is known other than that they occur and could play a critical role in sustaining hyphae through drought. The ultimate importance of mycorrhizae in plant–water relations depends on the drying patterns, the soil pore structure, and the number of hyphal connections extending from the root into the soil. New technologies are needed to adequately parameterize models of water horizontal flow patterns to: (i) observe and monitor the growth of roots and mycorrhizal fungi in situ; and (ii) describe the localized environment at high temporal and spatial resolution.
Horizontal Gene Transfer on Surfaces in Natural Porous Media: Conjugation and Kinetics
Authors: Massoudieh A. , Mathew A. , Lambertini E. , Nelson K. E. , Ginn T. R.
Published: May 2007

The transfer of genetic material among bacteria in the environment has been linked to a range of important phenomena related to bacterial adaptation and evolution, including bioremediation capability, metal tolerance, antibiotic resistance by pathogens in the environment, and gene flow from genetically modified microorganisms. Transfer of genetic material can occur among microorganisms present in both the planktonic and attached states. Given the propensity of organisms to exist in sessile communities under oligotrophic conditions, and that such conditions typify the subsurface, study of subsurface gene transfer phenomena should include processes and kinetics for a range of sessile community structures, from reversibly attached single cells to mature biofilms, as well as planktonic communities. This study very briefly reviewed horizontal, primarily conjugative, gene transfer in natural porous media, and the kinetics used to date to describe conjugative gene transfer in both planktonic (aqueous suspension) and sessile (surface associated) communities. The mathematics so far used to describe the kinetics of conjugation have developed largely from experimental observations of planktonic gene transfer, and are absent of time lags that occur between gene transfer events or plasmid stability that appear experimentally. We develop a novel formulation of delay‐difference equations for gene transfer for attached‐state microbes using an exposure‐time approach to account for lags.
Neutron Moisture Meter Calibration in Six Soils of Uzbekistan Affected by Carbonate Accumulation
Authors: Evett Steven , Ibragimov Nazirbay , Kamilov Bakhtiyor , Esanbekov Yusupbek , Sarimsakov Makhsud , Shadmanov Jamaliddin , Mirhashimov Rahmonkul , Musaev Ruzibay , Radjabov Tilak , Muhammadiev Bahram
Published: May 2007

Improvements in water use efficiency of the irrigated agriculture of Uzbekistan begin with determination of crop water use under its different climates, soils, and management practices. The neutron moisture meter (NMM) is a key tool for determination of crop water use, which we define here as being equal to transpiration and evaporation from the soil surface, i.e., the evapotranspiration. We accurately field calibrated NMMs at six locations in Uzbekistan, in soils ranging from deep, uniform silt loams of loessial origin to highly stratified alluvial soils near the Amu Darya River. In all soils, separate calibrations were found for the 10‐cm depth due to closeness to the soil–air interface. Near Tashkent and at the Syrdarya Branch Station, the soil below 10 cm was divided into two layers based on the increased CaCO3 content in the lower of the two layers. Distinctly different calibration equation slopes were found for these layers. At the Kashkadarya Branch Station, a single calibration was sufficient for the soil below 10 cm. At the Khorezm Branch Station, an abrupt change in soil texture at the 90‐cm depth required separate calibration equations for the 30‐ to 70‐cm depth range (silt loam) and the 110‐ to 170‐cm depth range (fine sand). Overall, the root mean square errors (RMSEs) of calibration ranged from 0.009 to 0.025 m3 m−3 and r2 values ranged from 0.91 to 0.99. Data gathered provide an excellent illustration of why calibration efforts should organize soil water content data by depth range. Two examples of profile water content measurement for crop water use studies are given.
Soil Micropore Development and Contributions to Soluble Carbon Transport within Macroaggregates
Authors: Smucker Alvin J.M. , Park Eun‐Jin , Dorner Jose , Horn Rainer
Published: May 2007

Soil biophysical transport mechanisms promoting biogeochemical sorption of soluble organic carbon (SOC) compounds within macroaggregates control the retention and release of most soil nutrients, C‐ and N‐based polysaccharides, and contaminants. Ecosystems containing continuous supplies of soluble root exudates and particulate organic matter (POM) provide a constant supply of mobile SOC compounds to surfaces and internal pore networks of soil aggregates. Intra‐aggregate pores, especially the ultrafine pores, appear to be developed, interconnected, and blocked or disconnected by repeated drying and wetting (DW) cycling with direct but unknown contributions to movement and retention of SOC compounds. There is evidence that the severity (e.g., range of soil water potential) and frequency of severe DW cycles control intra‐aggregate micro‐ and nanopore formation and function. Heterogeneously distributed microsites within aggregates contain microbial communities that readily mineralize available C and N compounds, producing mobile SOC that can be tightly sorbed to additional mineral surfaces made available within micro‐ and nanosized fissures during repeated DW cycling. Mechanical removal of concentric soil layers of aggregates, synchrotron imaging and computer microtomographic (CMT) image processing software of three‐dimensional pore networks and connectivities, coupled with synchrotron X‐ray small angle scattering to measure pore sizes. Natural isotopes of 13C and 15N to quantify C and N sorption and CO2 respiration provide new and integrated approaches for quantifying spatially heterogeneous changes of pore diameters, connectivities, and organo‐ion‐mineral sorption within intra‐aggregate pore networks. Net C and N alterations at surfaces and within aggregates appear to modify both the microbial activities and bacterial community structures, producing integrated feedback and feed‐forward processes between the soil biological and physical components of soil aggregates.
Preface: Soil Biophysical Contributions to Hydrological Processes in the Vadose Zone
Authors: Smucker Alvin J.M. , Hopmans Jan W.
Published: May 2007

Although significant progress has been made in our ability to characterize and quantify the soil physical environment and processes, there remains a critical gap in our understanding of interactions between the soil physical and biological realms. This was the impetus for the special symposium entitled “Soil Biophysics: A Challenging Interface” we organized for the 2005 SSSA Annual Meeting to increase awareness for the need to improve understanding of interactions between the soil physical environment, soil microorganisms, and plant roots. The symposium included research on the fate and transport of microorganisms (microbes and viruses), control and optimization of bioremediation and phytoremediation, physical controls on microbial ecology, improved descriptions of water and nutrient uptake by roots, and rhizosphere processes. This special section includes five selected articles derived from presentations at the soil biophysics symposium.
Application of Computational Fluid Dynamics to Closed‐Loop Bioreactors: I. Characterization and Simulation of Fluid‐Flow Pattern and Oxygen Transfer
Authors: Littleton Helen X. , Daigger Glen T. , Strom Peter F.
Published: May 2007

A full‐scale, closed‐loop bioreactor (Orbal oxidation ditch, Envirex brand technologies, Siemens, Waukesha, Wisconsin), previously examined for simultaneous biological nutrient removal (SBNR), was further evaluated using computational fluid dynamics (CFD). A CFD model was developed first by imparting the known momentum (calculated by tank fluid velocity and mass flowrate) to the fluid at the aeration disc region. Oxygen source (aeration) and sink (consumption) terms were introduced, and statistical analysis was applied to the CFD simulation results. The CFD model was validated with field data obtained from a test tank and a full‐scale tank. The results indicated that CFD could predict the mixing pattern in closed‐loop bioreactors. This enables visualization of the flow pattern, both with regard to flow velocity and dissolved‐oxygen‐distribution profiles. The velocity and oxygen‐distribution gradients suggested that the flow patterns produced by directional aeration in closed‐loop bioreactors created a heterogeneous environment that can result in dissolved oxygen variations throughout the bioreactor. Distinct anaerobic zones on a macroenvironment scale were not observed, but it is clear that, when flow passed around curves, a secondary spiral flow was generated. This second current, along with the main recirculation flow, could create alternating anaerobic and aerobic conditions vertically and horizontally, which would allow SBNR to occur. Reliable SBNR performance in Orbal oxidation ditches may be a result, at least in part, of such a spatially varying environment.
Improvements in Mixing Operations of Water Treatment Plants by Use of a Stable Finite Element Model
Authors: Vellando P. , Fe J. , Juncosa R. , Padilla F.
Published: May 2007

This work shows improvements made in mixing operations at water treatment plants, as a result of the hydrodynamic analysis of the mixing processes carried out by the use of a Finite Element Model. The code, developed in the Civil Engineering Department of the University of La Coruña, Spain, solves the Navier‐Stokes equations that rule viscous incompressible flow by using a Streamline Upwind/Petrov‐Galerkin (SUPG) stabilization technique. The incorporation of the SUPG formulation leads to obtaining stable solutions for Reynolds numbers of a moderate order in connection with meshes that are not very refined. Some water treatment units present significant deficiencies in their design. The numerical evaluation of the flow avoids the high expenses of the trial‐and‐error processes involved in installing and removing the mixing mechanisms and those derived from the need to halt the water treatment processes. As a result, an optimum design of the treatment plant is obtained at a low cost.
Effect of Copper(II) on Natural Organic Matter Removal During Drinking Water Coagulation Using Aluminum‐Based Coagulants
Authors: Liu Guojing , Zhang Xiangru , Talley Jeffrey W.
Published: May 2007

Coagulation has been proposed as a best available technology for controlling natural organic matter (NOM) during drinking water treatment. The presence of heavy metals such as copper(II) in source water, which may form copper–NOM complexes and/or interact with a coagulant, may pose a potential challenge on the coagulation of NOM. In this work, the effect of copper(II) on NOM removal by coagulation using alum or PAX‐18 (a commercial polymerized aluminum chloride from Kemiron Inc., Bartow, Florida) was examined. The results show that the presence of 1 to 10 mg/L of copper(II) in the simulated waters improved the total organic carbon (TOC) removal by up to 25% for alum coagulation and by up to 22% for PAX‐18 coagulation. The increased NOM removal with the presence of copper(II) in the waters can most likely be ascribed to the formation copper–NOM complexes that may be more adsorbable on aluminum precipitates and to the formation of copper(II) co‐precipitates that may also adsorb NOM. The presence of 1 to 5 mg/L of copper(II) in the waters containing 3 mg/L NOM as carbon was reduced below the maximum contaminant level goal (1.3 mg/L as copper) using either coagulant. The results suggest that the presence of copper(II) in source water may not adversely affect the NOM removal by coagulation. A good linear correlation was observed between the TOC removal efficiency and the log‐total moles of the precipitated metals, which include the metal ion from a coagulant and the divalent metal ion(s) in source water.
Quantification of Steroid Sex Hormones Using Solid‐Phase Extraction Followed by Liquid Chromatography–Mass Spectrometry
Authors: Filali‐Meknassi Youssef , Auriol Muriel , Adams Craig D. , Surampalli Rao Y.
Published: May 2007

In this study, the occurrence of trace amounts of natural and synthetic steroid estrogens in the aquatic environment was studied using liquid chromatography coupled with electrospray mass spectrometry, following solid‐phase extraction (SPE). The SPE was performed with C18 and NH2 cartridges. The first objective was to develop a reliable method for analyzing steroid estrogens (resulting from human and animal excretions) in different matrices. The method developed was then applied to quantify the occurrence of natural and synthetic hormones (estrone [E1], 17β‐estradiol [βE2], 17α‐estradiol [αE2], estriol [E3], and 17α‐ethinylestradiol [EE2]) in environmental samples in surface water and wastewater treatment plant (WWTP) influent and effluent. In the WWTP influents, βE2, αE2, and E3 were identified as ranging up to 72.6 ng/L in WWTP influent and to 16 ng/L in WWTP effluent. Analysis of surface water sampled upstream from the WWTP revealed the presence of all five estrogens, at levels up to 19.8 ng/L. These concentrations of estrogens pose an issue for large and small communities, because they are higher than the recommended guidelines for estrogen‐active compounds and because a lot of communities use surface water as drinking‐water sources.
Toward a High‐Rate Enhanced Biological Phosphorus Removal Process in a Membrane‐Assisted Bioreactor
Authors: Monti Alessandro , Hall Eric R. , Koch Fred A. , Dawson Robert N. , Husain Hadi , Kelly Harlan G.
Published: May 2007

A membrane enhanced biological phosphorus removal (MEBPR) process was studied to determine the impact of hydraulic retention time (HRT) and solids retention time (SRT) on the removal of chemical oxygen demand (COD), nitrogen, and phosphorus from municipal wastewater. The MEBPR process was capable of delivering complete nitrification independent of the prevailing operating conditions, whereas a significant improvement in COD removal efficiency was observed at longer SRTs. In the absence of carbon‐limiting conditions, the MEBPR process was able to achieve low phosphorus concentrations in the effluent at increasingly higher hydraulic loads, with the lowest HRT being 5 hours. The MEBPR process was also able to maintain optimal phosphorus removal when the SRT was increased from 12 to 20 days. However, at higher suspended solids concentrations, a substantial increase was observed in carbon utilization per unit mass of phosphorus removed from the influent. These results offer critical insights to the application of membrane technology for biological nutrient removal systems.
Functional Biodiversity of Microbial Communities in Aerobic Selector Slaughterhouse Wastewater
Authors: Al‐Mutairi Nayef Z.
Published: May 2007

The biodiversity of the microbial communities of an aerobic selector and a conventional system treating slaughterhouse wastewater were evaluated using the Biolog technique (Biolog Inc., Hayward, California). Principal components analysis of patterns and level of microbial activity indicate that microbial communities statistically differentiate between the selector and conventional system. Biolog data indicated that there was seasonal variation in the structure and function of the microbial community in conventional samples, which may be a useful indicator of wastewater community disturbance and unsteadiness, while, for the selector system, there were no recognizable statistical differences between winter and summer data communities.    Biodiversity indices indicated that the selector system maintained a high functional diversity (Shannon–Weaver diversity index [H′] from 3.8 to 4.6) than the conventional system (H′ from 1.8 to 2.8). The high values in the selector system were a reflection of the fact that most of the carbon sources were used, contributing to the very high Shannon indices. In addition, the high substrate equitability values (J) obtained for the selector samples indicated that the microbial communities between the summer and winter samples used the carbon sources in the same proportion. In contrast, differences in the equitability of the microbial communities within the conventional system were observed. This indicated a pattern representing unevenness.
Effect of Potassium Inhibition on the Thermophilic Anaerobic Digestion of Swine Waste
Authors: Chen Ye , Cheng Jay J.
Published: May 2007

The inhibition effects of high potassium concentration on thermophilic anaerobic digestion of swine waste were studied. A continuous stirred tank reactor (CSTR), operated at a hydraulic retention time of 10 days and chemical oxygen demand loading of 7.2 to 7.5 g/L/d, was used to digest swine waste and cultivate thermophilic anaerobic microorganisms. To evaluate the toxicity of potassium, batch inhibition tests were also conducted. Without acclimation to potassium, the inhibition threshold beyond which methane production decreased significantly was 3 g K +/L. Volatile fatty acids accumulation was observed during the decline of methane production. Propionic acid was the dominant fatty acid, indicating that propionic acid utilizers were more sensitive to potassium inhibition than acetoclastic methanogens. To test the effect of acclimation on potassium inhibition, the potassium concentration in the CSTR was increased to 6 and 9 g K +/L. Acclimation to 6 g K +/L increased the tolerance of anaerobic inocula to potassium inhibition without significantly reducing the methanogenic activity. The inhibition threshold was increased from 3 g K +/L for unacclimated inocula, to 6 g K +/L for inocula acclimated to 6 g/L of potassium. Acclimation of inocula to 9 g/L potassium further increased the inhibition threshold to 7.5 g K +/L. However, the overall methanogenic activity in the last case was lower than that of unacclimated and 6 g K +/L acclimated inocula.
Application of Non‐Linear Automatic Optimization Techniques for Calibration of HSPF
Authors: Iskra Igor , Droste Ronald
Published: May 2007

Development of TMDLs (total maximum daily loads) is often facilitated by using the software system BASINS (Better Assessment Science Integrating point and Nonpoint Sources). One of the key elements of BASINS is the watershed model HSPF (Hydrological Simulation Program Fortran) developed by USEPA. Calibration of HSPF is a very tedious and time consuming task, more than 100 parameters are involved in the calibration process. In the current research, three non‐linear automatic optimization techniques are applied and compared, as well an efficient way to calibrate HSPF is suggested. Parameter optimization using local and global optimization techniques for the watershed model is discussed. Approaches to automatic calibration of HSPF using the nonlinear parameter estimator PEST (Parameter Estimation Tool) with its Gauss‐Marquardt‐Levenberg (GML) method, Random multiple Search Method (RSM), and Shuffled Complex Evolution method developed at the University of Arizona (SCE‐UA) are presented.    Sensitivity analysis was conducted and the most and the least sensitive parameters were identified. It was noted that sensitivity depends on number of adjustable parameters. As more parameters were optimized simultaneously − a wider range of parameter values can maintain the model in the calibrated state. Impact of GML, RSM, and SCE‐UA variables on ability to find the global minimum of the objective function (OF) was studied and the best variables are suggested. All three methods proved to be more efficient than manual HSPF calibration. Optimization results obtained by these methods are very similar, although in most cases RSM outperforms GML and SCE‐UA outperforms RSM. GML is a very fast method, it can perform as well as SCE‐UA when the variables are properly adjusted, initial guess is good and insensitive parameters are eliminated from the optimization process. SCE‐UA is very robust and convenient to use. Logical definition of key variables in most cases leads to the global minimum.
An Expedient Variant of Heck Reaction of Alkenyl Nonaflates: Homogeneous Ligand‐Free Palladium Catalysis at Room Temperature
Authors: Vogel Michael A. K. , Stark Christian B. W. , Lyapkalo Ilya M.
Published: May 2007

A mechanistic study on the ligand‐free room‐temperature Heck reaction of alkenyl nonafluorobutanesulfonates (nonaflates) is described. Kinetic data obtained from poisoning experiments, centrifugation and variation of catalyst loading consistently provide evidence for a homogeneous palladium catalysis unprecedented in Heck chemistry. The Heck reaction of alkenyl perfluorobutanesulfonates represents a remarkably robust, active and efficient catalytic system generally applicable to the coupling with a broad range of terminal olefins including non‐activated ones under ambient conditions. It features insensitivity towards atmospheric oxygen and moisture, furnishing uniformly high yields of the anticipated coupling products without the necessity to purify commercial reagents and solvents.
Mesocellular Foam‐Supported Catalysts: Enhanced Activity and Recyclability for Ring‐Closing Metathesis
Authors: Lim Jaehong , Lee Su Seong , Riduan Siti Nurhanna , Ying Jackie Y.
Published: May 2007

Although ring‐closing metathesis (RCM) has been one of the most powerful methodologies for creating cyclic compounds, the pharmaceutical industry has not yet widely adopted this process commercially due to the high costs and leaching problems of homogeneous ruthenium catalysts. To circumvent these problems, we have immobilized the second‐generation Hoveyda–Grubbs catalyst effectively onto siliceous mesocellular foam (MCF). The open and interconnected pores of MCF facilitated ligand immobilization and substrate diffusion. We have observed that the ligand and metal loadings significantly affected the catalytic activity and recyclability. Enhanced recyclability by suppression of ruthenium leaching was achieved by using excess immobilized ligands. The resulting novel heterogenized catalysts demonstrated excellent activity and reusability for the RCM of various types of substrates.
Alkylation of Ammonium Salts Catalyzed by Imidazolium‐Based Ionic Liquid Catalysts
Authors: Zheng Zhuo Qun , Wang Jie , Wu Ting Hua , Zhou Xiao Ping
Published: May 2007

Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over imidazolium ionic liquid catalysts. The reaction gave almost stoichiometric amounts of the quaternary ammonium salts for halides and nitrates. It was found that the electron‐donating property of the alkyl moieties of ammonium cations, the electrophilic nature of the alkyl group of the carbonate, the acidity of the acid that the anion of the ammonium salt corresponds to, and the steric hindrance of the ammonium salts and the dialkyl carbonates are the key factors that influence the yields of quaternary ammonium salts. Strong electron‐donating alkyl groups on the nitrogen atom of the ammonium salt, electron‐withdrawing groups on the methylene carbon of dialkyl carbonate, and weaker steric hindrance of the starting ammonium salts and dialkyl carbonates favor the alkylation reaction of ammonium salts.
Development of Efficient and Reusable Diarylphosphinopolystyrene‐Supported Palladium Catalysts for CC Bond Forming Cross‐Coupling Reactions
Authors: Schweizer Stéphane , Becht Jean‐Michel , Le Drian Claude
Published: May 2007

Short and versatile syntheses of reusable diarylphosphinopolystyrene‐supported palladium catalysts 3a–j are described. The bis(o‐tolyl)phosphino catalyst 3b is particularly efficient for the Suzuki and Sonogashira cross‐couplings, whereas the bis(m‐tolyl)phosphino catalyst 3c is the most active catalyst for Heck reactions. The couplings are performed under non‐anhydrous reaction conditions and require only low amounts of supported palladium (0.5 mequivs. for Suzuki–Miyaura, 1.0 mequiv. for Sonogashira and 0.5 mequivs. for Heck reactions could be sufficient). Catalysts 3a–j are recovered by filtration and can be reused more than four times with no loss of efficiency.
TEMPO‐Copper(II) Diimine‐Catalysed Oxidation of Benzylic Alcohols in Aqueous Media
Authors: Figiel Paweł J. , Leskelä Markku , Repo Timo
Published: May 2007

In situ generated copper(II)‐diimine complexes combined with TEMPO (2,2,6,6‐tetramethylpiperidinyl‐1‐oxyl radical) were studied in the oxidation of benzylic alcohols, the focus being on enviromentally benign reaction conditions. In this respect, reactions were studied in aqueous alkaline solutions and dioxygen was used as an end oxidant. This simple catalytic system turned out to be highly efficient and selective in the oxidation of primary and secondary benzylic alcohols to their corresponding carbonyl compounds. Under optimised reaction conditions [5 mol % of TEMPO, 3 mol % of copper(II) diimine, pH 12.6–13.5, 80 °C, 10 bar O2] benzyl alcohol was quantitatively and selectively oxidised to benzaldehyde. According to ESI‐MS studies, coordination of TEMPO, as well as deprotonated benzyl alcohol to the parent copper‐diimine complex in aqueous solutions is feasible. Supported by these observations a plausible reaction mechanism is proposed for the oxidation reaction.
A Microwave‐Enhanced, Lewis Acid‐Catalyzed Synthesis of 1,3‐Dioxolanes and Oxazolines from Epoxides
Authors: Benfatti Fides , Cardillo Giuliana , Gentilucci Luca , Tolomelli Alessandra , Monari Magda , Piccinelli Fabio
Published: May 2007

A fast and highly regio‐ and stereoselective transformation of non‐conventional β‐lactam‐containing epoxides into the corresponding cyclic 1,3‐dioxolanes and oxazolines is herein reported, using microwave irradiation as an efficient source of energy, in the presence of stoichiometric or catalytic amounts of Lewis acids, without an additional solvent. These cyclic compounds are the protected forms of diols and amino alcohols.
Friedländer Synthesis of Quinolines Using a Lewis Acid‐Surfactant‐Combined Catalyst in Water
Authors: Zhang Liang , Wu Jie
Published: May 2007

In water, Friedländer annulation using Lewis acid‐surfactant‐combined catalyst provides a mild and efficient route for the synthesis of quinolines. Employing a catalytic amount of scandium tris(dodecyl sulfate) [Sc(O3SOC12H25)3], various polysubstituted and polycyclic quinolines were obtained in exellent yields.
Highly Regio‐ and Stereoselective Copper(I) Chloride‐Mediated Carbometallation of 2,3‐Allenols with Grignard Reagents
Authors: Lu Zhan , Ma Shengming
Published: May 2007

An efficient highly regio‐ and stereoselective copper(I) chloride‐mediated carbometallation of differently substituted 2,3‐allenols with primary or secondary alkyl or aromatic Grignard reagents followed by iodination to synthesize fully‐substituted allylic alcohols has been developed. This protocol introduces the R4 group from the Grignard reagent to the terminal position of the 2,3‐allenols.
Direct Catalytic Asymmetric Aldol Reactions Assisted by Zinc Complex in the Presence of Water
Authors: Paradowska Joanna , Stodulski Maciej , Mlynarski Jacek
Published: May 2007

A combination of zinc triflate and chiral C2‐symmetrical prolinamide ligand leads to high enantioselectivities in direct aldol reactions essentially assisted by water. The presence of 5 mol % of the catalyst affords an asymmetric intermolecular aldol reaction between unmodified ketones and aldehydes to give anti‐products with excellent enantioselectivities ranging from 86–98 % ee. The same bis(prolinamide) ligand is found to catalyze the direct aldol reactions in the presence of water (or in water) with excellent stereocontrol and furnish the corresponding aldols in up to 99 % ee. For the demonstrated catalytic systems organic solvent‐free conditions are applied.
A Simple Organocatalytic Enantioselective Cyclopropanation of α,β‐Unsaturated Aldehydes
Authors: Rios Ramon , Sundén Henrik , Vesely Jan , Zhao Gui‐Ling , Dziedzic Pawel , Córdova Armando
Published: May 2007

A highly chemo‐ and enantioselective organocatalytic cyclopropanation of α,β‐unsaturated aldehydes with bromomalonate and 2‐bromoacetoacetate esters is presented. The reaction is catalyzed by chiral amines and gives access to 2‐formylcyclopropanes in high yields and up to 99 % ee.
Cornelia de Lange syndrome: Clinical review, diagnostic and scoring systems, and anticipatory guidance
Authors: Kline Antonie D. , Krantz Ian D. , Sommer Annemarie , Kliewer Mark , Jackson Laird G. , FitzPatrick David R. , Levin Alex V. , Selicorni Angelo
Published: May 2007

Cornelia de Lange syndrome (CdLS), also known as Brachmann‐de Lange syndrome, is a well‐described multiple malformation syndrome typically involving proportionate small stature, developmental delay, specific facial features, major malformations (particularly the cardiac, gastrointestinal and musculoskeletal systems), and behavioral abnormalities. There is a broad spectrum of clinical involvement, with increasing recognition of a much milder phenotype than previously recognized. Significant progress has been made in recent years in the clinical and molecular delineation of CdLS, necessitating a revision of the diagnostic criteria, more inclusive of the milder cases. In addition, a scoring system of severity has been found to correlate with specific brain changes. Thus, a clinical overview and recommendations for anticipatory guidance are timely in aiding caretakers and professionals to individualize care decisions and maximize developmental potential for individuals with CdLS. These guidelines are derived from consensus based on collective experience of over 500 patients with CdLS, observations of the natural history in children, adolescents, and adults, a review of the literature, and contacts with national support organizations in North America and Europe. © 2007 Wiley‐Liss, Inc.
The Val66Met polymorphism of the brain‐derived neurotrophic factor gene is associated with psychotic feature and suicidal behavior in Japanese major depressive patients
Authors: Iga Jun‐Ichi , Ueno Shu‐Ichi , Yamauchi Ken , Numata Shusuke , Tayoshi‐Shibuya Sumiko , Kinouchi Sawako , Nakataki Masahito , Song Hongwei , Hokoishi Kazuhiko , Tanabe Hirotaka , Sano Akira , Ohmori Tetsuro
Published: May 2007

Recent researches have suggested that brain‐derived neurotrophic factor (BDNF) may be implicated in the pathophysiology of mood disorder. This study examined the association between the BDNF Val66Met polymorphism and major depressive disorder (MDD) in a Japanese population. We genotyped the BDNF Val66Met polymorphism in 154 major depressive patients and 154 age‐ and sex‐matched control subjects. The genotypic distributions and allele frequencies were similar among the patients and control subjects. When the relationships of the polymorphism with several clinical variables (i.e., age, sex, age of onset, number of episode, presence of psychotic features, suicidal behavior, and family history) were examined, the dose of Met allele had significant effects on psychotic feature and suicidal behavior and family history. These results suggest that the BDNF Val66Met polymorphism is not related to the development of MDD but related to clinical features of MDD in a Japanese population. © 2007 Wiley‐Liss, Inc.
A novel intronic polymorphism of ABCA1 gene reveals risk for sporadic Alzheimer's disease in Chinese
Authors: Chu Leung Wing , Li Yan , Li Zhong , Tang Alan YB , Cheung Bernard MY , Leung Raymond YH , Yik Ping‐Yiu , Jin Dong‐Yan , Song You‐Qiang
Published: May 2007

Recent genetic studies have shown that variants of the ATP‐binding cassette transporter A1, ABCA1, may be implicated in the pathogenesis of Alzheimer's disease (AD). In this case‐control study, a panel of 19 single nucleotide polymorphisms (SNP) (including three amino‐acid‐coding SNPs used for replication of previous work, and 16 newly selected intronic tag SNPs) was genotyped. Nominally significant single marker P‐values were observed in four SNPs, with the highest score of 0.003 for rs2297404 (OR = 1.88, 95%CI 1.23–2.87). In addition, six distinct linkage disequilibrium (LD) blocks were detected. LD block1 harbored three nominally significant SNPs (rs2297404, rs2230808, and rs2020927), and showed a different haplotype structure in the affected and unaffected groups. Of the four haplotypes identified, haplotype2 (CAC) was more prevalent in the disease group (0.323 in AD vs. 0.202 in control); while haplotype1 (TGG) was over‐represented in the healthy controls (0.595 in control vs. 0.493 in AD), indicating disease risk conferring possibility of haplotype2. After doubling the sample size, the three nominally significant SNPs were still significantly associated with AD. Although coding SNP (rs2230808) was confirmed to have a significant association with AD, prediction of the effects of an amino acid substitution SNP rs2230808 (R1587K) on the three‐dimensional structure and function of the ABCA1 protein using PolyPhen program revealed that it is unlikely to be functionally significant. However, the adjacent rs2297404 in the same LD block is potentially functionally significant because of its position in the immediate vicinity of a splicing branch site. Further functional analysis of this polymorphism should be a high priority. © 2007 Wiley‐Liss, Inc.
Effect of interleukin‐1β gene functional polymorphism on dorsolateral prefrontal cortex activity in schizophrenic patients
Authors: Papiol Sergi , Molina Vicente , Rosa Araceli , Sanz Javier , Palomo Tomás , Fañanás Lourdes
Published: May 2007

Hypoactivity of the dorsolateral prefrontal cortex (DLPFC) during cognitive tasks is among the most consistent findings in schizophrenia. The biological factors contributing to this hypofrontality are only partially known. Previous reports have shown the influence of genes mapped to IL‐1 cluster (i) in the risk to develop schizophrenia and (ii) on brain morphological abnormalities in these patients. Moreover, Interleukin‐1β (IL‐1β), encoded by IL‐1B gene (IL‐1 cluster, chromosome 2q13) has a key role in dopaminergic differentiation and dendrite growth in developing cortical neurons. The authors explored the role of a genetic functional polymorphism at IL‐1B gene in relation to DLPFC activity. DLPFC (left and right) metabolic activity was measured in a sample of 19 DSM‐IV diagnosed schizophrenic patients of Spanish origin using a procedure based on MRI/PET image fusion. During PET studies, subjects performed a contingent Continuous Performance Test aiming to activate DLPFC. Functional promoter polymorphism −511 C/T (rs16944) of IL‐1B gene was genotyped in these patients. Those patients who were allele 2 (−511 T) carriers showed a lower metabolic activity in the left DLPFC with respect to patients homozygous for allele 1 (−511 C) (U = 16, z = −2.32, P = 0.02). Our results suggest that hypofrontality reported in some schizophrenic patients might be explained, at least in part, by this functional polymorphism at IL‐1B gene. Genetic variants with influence on brain functionality may account for the neurocognitive heterogeneity observed in schizophrenic patients. © 2007 Wiley‐Liss, Inc.
Photoelektrische Erscheinungen am feuchten Jodsilber
Authors: Scholl Hermann
Published: May 2007

Verfahren zur Isolierung der spezifischen Violettwirkung p. 417. 16. Spektralbereich, in welchem wesentlich nur die spezifische Violettwirkung auftritt p. 421. 17. Einfluß von freiem Jod bei violetter Bestrahlung p. 422. 18. Verhalten des Dunkelwiderstandes nach violetter Belichtung p. 423. 19. Δ V und Δ W im Violett; Abhängigkeit von Lichtstärke etc. p. 427. 20. Die im violetten Lichte entstehenden Elektrizitätsträger dringen in weit größere Tiefen ein als das Licht selbst p. 429. 21. Leitfähigkeitszunahme der violett bestrahlten Oberflächenschicht feuchten Jodsilbers p. 434. 22. Zerfall des belichteten Jodsilbers in seine Ionen gibt nicht ausreichende Erklärung, weil die Löslichkeitszunahme nicht entfernt parallel der Leitfähigkeitserhöhung steigt p. 437. 23. Ebenso andere elektrolytische Ionen auszuschließen p. 441. 24 und 25. Berechnung einer unteren Grenze für die Beweglichkeit der Lichtionen im festen Jodsilber p. 443 u. 448. 26. Lichtionen sind wahrscheinlich freie Elektronen p. 456. 27. Auffassung aller weiteren Vorgänge als Wirkungen der durch Belichtung entstehenden Kathodenstrahlen p. 459. 28. Lichtionen in dem durch violette Vorbelichtung entstandenen Stoffe p. 461.
Über die Wiederholung des Harressschen Versuches
Authors: Pogány Béla
Published: May 2007

Der von der Firma Carl Zeiss freundlichst Überlassene Apparat wurde in Budapest mit Unterstützung der Elizabeth Thompson Science Fund aufgebaut. Beiden Körperschaften gebührt mein innigster Dank.
Über Normalmaterialien für Ausdehnungsmessungen an festen Körpern bis zu 1400°C
Authors: Cohn Willi M.
Published: May 2007

über die Ergebnisse früherer Messungen an verschiedenen Materialien gegeben, welche als Normalmaterialien für Ausdehnungsmessungen an festen Körpern nach der Vergleichsmethode Verwendung finden können. Dann wird über Untersuchungen berichtet, welche mit Hilfe neuer, hier kurz beschriebener Apparaturen durchgeführt wurden und welche die Eignung verschiedener Substanzen zur Verwendung als Normalmaterialien für Ausdehnungsmessungen bis zu 1400°C festzustellen bezweckten. – Untersucht wurden Kieselglas, Zirkondioxyd, sowie verschiedene keramische Materialien. Es zeigte sich, daß Kieselglas und Zirkondioxyd bis zu 1000°C etwa Verwendung finden können, neuartige Steinzeugmassen bis zu Temperaturen von etwa 1200°C und feuerfeste Marquardtsche Masse bis zu 1400°C. – Schließlich wird auf eine neue Apparatur hingewiesen, welche auf Grund dieser Ergebnisse entwickelt worden ist.
Über interferometrische Abstandsmessungen in Benzol‐ und Tetrabromkohlenstoff‐Molekülen mittels Röntgenstrahlen
Authors: Rumpf E.
Published: May 2007

Es werden interferometrische Untersuchungen an flüssigem Benzol und gelöstem CBr4 beschrieben und die Dimensionen der Moleküle angegeben.