bluuebunny/crossref_metadata_2025 huggingface dataset:
Applied Linguistics in“dialogue”with hermeneutics in discoursing “the intercultural” in educationalpraxis
Authors: Papademetre Leo
Published: May 2008

Ever since the Socratic-Platonic inquiry on the nature of language, linguistic and socio-cultural thinking in Eurocentric academic cultures about human communication has been discoursed from various philosophical perspectives based on diverse conceptualisations, perceptions, understandings, notions, theories, descriptions and explanations of the variable phenomena observed in intra- and intercultural interaction and communication. In the variable research areas of applied linguistics ‘scholars from a variety of disciplines have applied themselves to defining what the nature of intercultural communication might be and how it might be taught’ (Kramsch, 2002, p. 277). However, in the concerted effort to apply our understanding of “the intercultural” in our research and educationalpraxis, we ‘have no other recourse but discourse itself – the discourse of [our] discipline, laid out on the page as disciplinary truth. And that, as James Clifford (Clifford, 1988) would say, is the “predicament of culture”’ (Kramsch, 2002, p. 282). In the following essay, this “predicament” is examined in the contexts of the discourse tradition which centres on “dialogue” as a valued means of understanding self-and-otherintra-and-inter-culturally. Discussion will focus on how “dialogue” can impose “situated/positioned” ways of interpreting and understanding “the intercultural” in languages education, especially when it defers engaging with variable-linguisticalityand variable-traditionalityin its discourse tradition.
Fractal Analysis of Pore Roughness in Images of Soil Using the Slit Island Method
Authors: Papadopoulos Apostolos , Bird Nigel R. A. , Mooney Sacha J. , Whitmore Andrew P.
Published: May 2008

A description and quantification of the surface of soil pores is important to promote our understanding of soil function because these surfaces provide sites for biological, chemical, and physical processes within the soil. Previous attempts to characterize the geometry of pore surfaces have included the slit island method, which is used to extract a fractal dimension to describe the roughness of the pore perimeters in two dimensions. Our objective in this study was to assess how this approach might be robustly applied to images of soil pore structure. Critical to the success of the technique is constancy of shape in the set of pores analyzed. We applied additional analysis to test whether this criterion is met, using the convex cover and the convexity of a two‐dimensional object. This additional analysis coupled with the slit island method was applied to a soil image. In this instance, we were unable to detect a set of pores of common shape and concluded that the fractal dimension of value 1.4 derived from the image reflects not a fractal pore perimeter but rather an increasing complexity of pore shape with increasing pore size. We concluded that the analysis of pore shape proposed here, in addition to scaling of pore perimeter, is critical to sensibly describe the geometry of soil pore perimeters.
Spatial Scaling Analyses of Soil Physical Properties: A Review of Spectral and Wavelet Methods
Authors: Si Bing Cheng
Published: May 2008

Understanding the scaling properties of soil spatial variability is important for managing natural resources and protecting our environment. Our objective was to present methodology that has been used or has the potential to be used in spatial scaling of soil properties. The spectral and wavelet analyses were presented and illustrated using the soil hydraulic conductivity and other basic soil physical properties collected along a transect in Saskatchewan, Canada. We introduced periodogram, spectral analysis, simple squared coherency, and multiple coherency analyses as the frequency domain tools. For the wavelet analysis, the wavelet transform, cross wavelet spectrum, and simple wavelet coherency analysis were introduced. Detailed procedures and precautions for these analyses were also presented. The significance tests for different analyses were discussed and multiple testing for the wavelet analysis was introduced.
Leaching with Subsurface Drip Irrigation under Saline, Shallow Groundwater Conditions
Authors: Hanson Blaine , Hopmans Jan W. , Šimůnek Jirka
Published: May 2008

One option for coping with the high soil salinity levels caused by saline, shallow groundwater conditions along the west side of the San Joaquin Valley is to convert from sprinkler or surface irrigation methods to drip irrigation. Experiments in commercial fields revealed that subsurface drip irrigation of processing tomato (Lycopersicon esculentum Mill. var. esculentum) is highly profitable under these conditions compared with other irrigation methods. The experiments also showed that little or no field‐wide leaching occurred, based on the conventional or water balance approach to estimating the leaching fraction (LF), yet soil salinity measurements showed considerable leaching around the drip lines. Actual LFs could not be calculated because LF, soil salinity, soil water content, and root density all varied with distance and depth around the drip lines. Therefore, we conducted a numerical modeling study using the HYDRUS‐2D computer simulation model to evaluate leaching with drip irrigation under saline, shallow groundwater conditions for different amounts of applied water, water table depths, and irrigation water salinity, described by the electrical conductivity of the irrigation water (ECiw). Results showed that LF values ranged from 7.7 to 30.9% as applied water amounts increased from 60 to 115% of the potential evapotranspiration (ETpot) for the ECiw = 0.3 dS m−1 irrigation water, even though the water balance method showed no leaching for applied water amounts equal to or smaller than ETpot The spatially varying soil wetting patterns that occur under drip irrigation caused the localized leaching, which was concentrated near the drip line.
Sequential Coupling of Models for Contaminant Spreading in the Vadose Zone
Authors: Class Holger , Helmig Rainer , Neuweiler Insa
Published: May 2008

The numerical simulation of contaminant spreading in the vadose zone as well as the modeling of remediation scenarios requires, in general, very sophisticated model concepts. Particularly, compositional and nonisothermal effects increase the complexity of a model significantly. This makes the solution of large systems computationally costly. To save computation time, it is reasonable to adjust the required model complexity to the complexity of the relevant physical processes. The relevant physical processes governing the system's behavior can change for distinct time scales. This can be taken into account by models that are adapted to the respective processes, which can be coupled sequentially.
Spatially Distributed Water Fluxes in an Andisol under Banana Plants: Experiments and Three‐Dimensional Modeling
Authors: Sansoulet Julie , Cabidoche Yves‐Marie , Cattan Philippe , Ruy Stéphane , Šimůnek Jirka
Published: May 2008

Water fluxes in the subsurface of forested and agricultural ecosystems vary spatially across wide ranges because of several interconnected phenomena. On the one hand, subsurface environments are often highly heterogeneous. On the other hand, infiltration water is often distributed unevenly due to aboveground interception and redistribution of rainfall by the plant canopy. These phenomena have important hydro‐ecological consequences because they significantly affect groundwater recharge and nutrient leaching. Field experiments involving subsurface lysimeters and tensiometers were performed to quantify the spatial distribution of fluxes in an Andisol under a banana plant (Musa acuminata Colla). Wick lysimeters were installed at a depth of 70 cm at several locations with respect to the banana stem to measure the spatial distribution of subsurface water fluxes. Collected experimental data were simulated using the HYDRUS software package, which numerically solves the Richards equation describing three‐dimensional variably saturated water flow in the subsurface. Spatially distributed drainage fluxes were well reproduced with the numerical model. Due to the impact of stemflow, drainage volumes under the banana stem were up to six times higher than in the row downstream from the stem, as well as between rows, as these areas were sheltered from direct rainfall by the banana leaves and received only throughfall.
Simulating Water, Solute, and Heat Transport in the Subsurface with the VS2DI Software Package
Authors: Healy Richard W.
Published: May 2008

The software package VS2DI was developed by the U.S. Geological Survey for simulating water, solute, and heat transport in variably saturated porous media. The package consists of a graphical preprocessor to facilitate construction of a simulation, a postprocessor for visualizing simulation results, and two numerical models that solve for flow and solute transport (VS2DT) and flow and heat transport (VS2DH). The finite‐difference method is used to solve the Richards equation for flow and the advection–dispersion equation for solute or heat transport. This study presents a brief description of the VS2DI package, an overview of the various types of problems that have been addressed with the package, and an analysis of the advantages and limitations of the package. A review of other models and modeling approaches for studying water, solute, and heat transport also is provided.
Impact of Soil Micromorphological Features on Water Flow and Herbicide Transport in Soils
Authors: Kodešová Radka , Kočárek Martin , Kodeš Vít , Šimůnek Jirí , Kozák Josef
Published: May 2008

The impact of varying soil micromorphology on soil hydraulic properties and, consequently, on water flow and herbicide transport observed in the field is demonstrated on three soil types. The micromorphological image of a humic horizon of Haplic Luvisol showed higher‐order aggregates. The majority of detectable pores corresponding to the pressure head interval between −2 and −70 cm were highly connected, separating higher‐order peds with small intrapores that possibly formed zones with immobile water. Herbicide was regularly distributed in this soil. The majority of detectable large capillary pores in a humic horizon of Greyic Phaeozem were separated and affected by clay coatings and fillings. The herbicide transport in this soil was highly affected by preferential flow. Macropores corresponding to pressure heads higher than −2 cm were detected in a humic horizon of Haplic Cambisol. However, preferential flow only slightly influenced the herbicide transport in this soil. Single‐porosity and either dual‐porosity or dual‐permeability flow and transport models in HYDRUS‐1D were used to estimate the soil hydraulic parameters from laboratory multistep outflow and ponded infiltration experiments via numerical inversion and to simulate the herbicide transport experimentally studied in the field. Appropriate models were selected on the basis of the soil micromorphological study.
Modeling Coupled Hydrologic and Chemical Processes: Long‐Term Uranium Transport following Phosphorus Fertilization
Authors: Jacques D. , Šimůnek J. , Mallants D. , van Genuchten M.Th.
Published: May 2008

Coupling physical and geochemical processes within one integrated numerical simulator provides a process‐based tool for investigating the mobility of contaminants as affected by changing hydrologic regimes and geochemical conditions. We review interactions between physical and biogeochemical processes in the vadose zone, and then present a case study demonstrating these complex interactions. A hypothetical application is presented of the HP1 multicomponent transport simulator to predict the transport of two major elements (Ca and P) and one trace element (U) applied annually for 200 yr to a field soil in the form of an inorganic P fertilizer. Interactions of Ca, P, and U with the solid phase are described using cation exchange and surface complexation reactions. Simulations assuming steady‐state or transient flow conditions were analyzed in terms of temporal variations of the linear distribution coefficient, Kd, which depends strongly on pH and the composition of the aqueous phase. If the composition of the aqueous phase is constant, adsorption of Ca and U increases with increasing pH. Due to the annual addition of Ca, P, and U, and competition between P and U for sorption sites, the Kd of these elements decreased with time near the soil surface. Deeper in the soil, the Kd of U followed the pH increase because of a lack of competition from P. Because of the combined effects of changing hydrologic and geochemical conditions, the Ca and U distribution coefficients and solute fluxes during the transient simulation exhibited large short‐time variations of up to three orders of magnitude.
Vertical Confinement of Injected Steam in the Vadose Zone Using Cold Air Injection
Authors: Hodges Rex A. , Falta Ronald W.
Published: May 2008

Steam flooding is used for removal of volatile organic contaminants (VOCs) from concentrated source zones. The application of steam flooding to shallow vadose zone sites can be problematic if the steam or contaminants vent to the ground surface. Cold air injection holds promise as a technique for controlling the vertical movement of the injected steam. A series of two‐dimensional numerical simulations using a radially symmetric grid show the sensitivity of this process to geological and operational parameters. Air control of vertical steam movement appears to be a useful technique, using approximately equal air and steam volumetric flow rates. Air injection is shown to be more effective than a low‐permeability cap at the ground surface for keeping high temperatures away from the surface. The most effective design appears to be a combination of a low‐permeability surface cap and air injection above the steam injector. The cap mainly serves to direct the air flow, preventing it from exiting at the ground surface near the air injection point.
Single‐ and Multiscale Remote Sensing Techniques, Multifractals, and MODIS‐Derived Vegetation and Soil Moisture
Authors: Lovejoy S. , Tarquis A. M. , Gaonac'h H. , Schertzer D.
Published: May 2008

Scaling processes are increasingly understood to be the result of nonlinear dynamic mechanisms repeating scale after scale from large to small scales leading to nonclassical resolution dependencies. This means that the statistical properties systematically vary in strong, power‐law ways with the resolution. When present in geophysical and remotely sensed fields, it implies that when classical (single‐scale) remote sensing algorithms are used to determine surrogates of various geophysical fields, they can at most be correct at the unique (and subjective) calibration resolution. Scaling analysis and modeling techniques were applied to MODIS TERRA Bands 1 through 7 and to the standard derived vegetation and soil moisture indices in order to quantitatively characterize the wide range of scaling of these fields. The scaling exponents we found are not so large; however, they act across wide scale ranges and imply large effects. For example, for the statistics near the mean, the MODIS (500‐m) resolution would be biased by a factor of ∼1.52 when compared with similar results from an “ideal” sensor at 1‐mm resolution. Applying the standard index algorithms on lower and lower resolution satellite data, we obtained indices with significantly different statistical properties than if the same algorithm was used at the finest resolution and then degraded to an intermediate value (a difference of a factor ∼1.54). This shows that the algorithms can, at best, be accurate at the unique calibration scale and this points to the need to develop resolution‐independent algorithms based on the scaling exponents.
Seasonal Effect on Tree Species Classification in an Urban Environment Using Hyperspectral Data, LiDAR, and an Object- Oriented Approach
Authors: Voss Matthew , Sugumaran Ramanathan
Published: May 2008

The objective of the current study was to analyze the seasonal effect on differentiating tree species in an urban environment using multi-temporal hyperspectral data, Light Detection And Ranging (LiDAR) data, and a tree species database collected from the field. Two Airborne Imaging Spectrometer for Applications (AISA) hyperspectral images were collected, covering the Summer and Fall seasons. In order to make both datasets spatially and spectrally compatible, several preprocessing steps, including band reduction and a spatial degradation, were performed. An object-oriented classification was performed on both images using training data collected randomly from the tree species database. The seven dominant tree species (Gleditsia triacanthos, Acer saccharum, Tilia Americana, Quercus palustris, Pinus strobus and Picea glauca) were used in the classification. The results from this analysis did not show any major difference in overall accuracy between the two seasons. Overall accuracy was approximately 57% for the Summer dataset and 56% for the Fall dataset. However, the Fall dataset provided more consistent results for all tree species while the Summer dataset had a few higher individual class accuracies. Further, adding LiDAR into the classification improved the results by 19% for both fall and summer. This is mainly due to the removal of shadow effect and the addition of elevation data to separate low and high vegetation.
The Very‐Low Shear Modulus of Multi‐Walled Carbon Nanotubes Determined Simultaneously with the Axial Young's Modulus via in situ Experiments
Authors: Wei Xian‐Long , Liu Yang , Chen Qing , Wang Ming‐Sheng , Peng Lian‐Mao
Published: May 2008

The natural frequencies (f) as a function of the length (L) of single, multi‐walled carbon nanotubes (CNTs) are measured using the electric‐field‐induced resonance method together with the “nanoknife” technique for cutting nanotubes to the desired length. The experimental f‐L data for short CNTs are found to be adequately described by the Timoshenko beam model, but not by the widely‐used Euler‐Bernouilli beam model. The failure of the Euler‐Bernouilli beam model is due to its neglect of the significant effect of shear deformation caused by the extremely‐anisotropic mechanical properties of CNTs. The axial Young's modulus and radial shear modulus of CNTs are obtained simultaneously through fitting the experimental f‐L data with the Timoshenko beam model.
Functionalized Asymmetric Linear Acenes for High‐Performance Organic Semiconductors
Authors: Tang Ming L. , Reichardt Anna D. , Okamoto Toshihiro , Miyaki Nobuyuki , Bao Zhenan
Published: May 2008

A series of compounds from the tetraceno[2,3‐b]thiophene and the anthra[2,3‐b]thiophene family of semiconducting molecules has been made. Specifically, synthetic routes to functionalize the parent molecules with bromo and then hexyl groups are shown. The bromo‐ and hexyl‐functionalized tetraceno[2,3‐b]thiophene and anthra[2,3‐b]thiophene were characterized in the top‐contact thin‐film transistor (TFT) geometry. They give high mobilities, ranging from 0.12 cm2 V−1 s−1 for α‐n‐hexylanthra[2,3‐ b]thiophene to as high as 0.85 cm2 V−1 s−1 for α‐bromotetraceno[2,3‐b]thiophene. Notably, grain size increases, going from the shorter anthra[2,3‐b]thiophene core to the longer tetraceno[2,3‐b]thiophene core, with a corresponding increase in mobility. The transition from undesirable 3D to desirable 2D thin‐film growth is explained by the increase in length of the molecule, in this case by one benzene ring, which results in an increase in intralayer interactions relative to interlayer interactions.
Developments in Nanostructured Cathode Materials for High‐Performance Lithium‐Ion Batteries
Authors: Wang Ying , Cao Guozhong
Published: May 2008

Nanostructured materials lie at the heart of fundamental advances in efficient energy storage and/or conversion, in which surface processes and transport kinetics play determining roles. This Review describes some recent developments in the synthesis and characterization of nanostructured cathode materials, including lithium transition metal oxides, vanadium oxides, manganese oxides, lithium phosphates, and various nanostructured composites. The major goal of this Review is to highlight some new progress in using these nanostructured materials as cathodes to develop lithium batteries with high energy density, high rate capability, and excellent cycling stability resulting from their huge surface area, short distance for mass and charge transport, and freedom for volume change in nanostructured materials.
Relatedness in wild chimpanzees: Influence of paternity, male philopatry, and demographic factors
Authors: Inoue Eiji , Inoue‐Murayama Miho , Vigilant Linda , Takenaka Osamu , Nishida Toshisada
Published: May 2008

In chimpanzees (Pan troglodytes), high‐ranking males are expected to have high reproductive success and females typically emigrate upon reaching maturity. Although high average relatedness among males in the same social groups has been assumed, previous reports have indicated that relatedness among males is not necessarily significantly higher than that among females. The paternity of 11 offspring and the relatedness of 50 individuals in the M group of chimpanzees at Mahale Mountains National Park, Tanzania, were investigated using DNA analyses. We determined the fathers of 10 offspring. Two different alpha males sired a total of five offspring, whereas the other males had low reproductive success. The proportion of paternal half‐sibling pairs among the 10 offspring was 15.6%. The average relatedness among mature males was significantly higher than that among mature females. The existence of an old male and the long tenure of one alpha male may have contributed to this significant difference. The average dyadic relatedness among mature natal individuals was significantly higher than that in natal‐immigrant pairs in which the individuals came from different groups. The average relatedness among immigrant females was similar to that in pairs of natal and immigrant females, suggesting that the immigrants came from various groups. Thus, female transfer acts to maintain low average relatedness within the group. A comparison of our results to those from other study sites suggests that although the average relatedness among adult males does not reach the level of half‐siblings, under some circumstances it can exceed the relatedness of females. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Adsorption of Cu2+ ions with poly(N‐isopropylacrylamide‐co‐methacrylic acid) micro/nanoparticles
Authors: Wu Qinglin , Tian Peng
Published: May 2008

Chelation efficiency of stimuli‐responsive poly(N‐iospropylacrylamide‐co‐methyacrylic acid) (PNIPAAm‐MAA) nanoparticles with Cu2+ ions from CuSO4·5H2O solution and from wood treated with copper‐based preservatives was studied. It was shown that particle size played a very important role in the adsorption process. The nano‐scale particles showed much improved Cu ion adsorption efficiency, compared with the micro hydrogels. The amount of Cu ion adsorption increased with increase of MAA ratio in copolymers and adsorption efficiency decreased with increased particle size. Furthermore, the adsorption amount varied with adsorption temperature at temperatures both below and above the corresponding low critical solution temperature (LCST). The high adsorption efficiency of Cu ions by PNIPAAm‐MAA polymer particles provides an effective technique for recovering metal ions (e.g., Cu2+) from wood treated with metal‐based preservatives. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of DC conductivity of PPy anode on Li/PPy secondary batteries
Authors: Ren Li , Su Liwei , Chen Xiaofeng
Published: May 2008

Polypyrrole(PPy) was first synthesized by chemical oxidative polymerization. Then the assembling of cells was made by using PPy as anode and the lithium cathode. Its electrochemical properties were tested using galvanostatic system. The influences of DC conductivity of PPy anode on Li/PPy secondary batteries were mainly studied. The results showed when using high conductivity PPy as anode active material, the doping–undoping of the anions was easy and the discharge capacity of the cell was high, after fifty cycles the coulombic efficiency was 99.2%, the electrochemical stability and cycling property were still good. From condensed matter physics, the doping manner of conducting PPy was explained. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Findings of extensive variation in the types of outcome measures used in hip and knee replacement clinical trials: A systematic review
Authors: Riddle Daniel L. , Stratford Paul W. , Bowman Dixie H.
Published: May 2008

Objective

To describe the extent of variation in outcome measure usage in hip and knee replacement randomized trial literature, and to summarize this variation in the context of the International Classification of Functioning, Disability, and Health (ICF) conceptual model created by the World Health Organization (WHO).

Methods

We used a defined search strategy in Medline and EMBase databases to identify articles published from January 2000 to February 2007. Studies were reviewed if they were randomized trials with a ≥6‐week followup and if they used noninvasive outcome measures of impaired joint function or whole‐person limitations in daily activities or functional status. The WHO ICF model was used to categorize outcome measures.

Results

Of 972 studies, 160 were included for review. Of these, 82 were conducted on patients with hip replacements, 75 on patients with knee replacements, and 3 on patients with both. The most common outcome measure in knee trials was the American Knee Society score (used in 48% of reviewed studies), and in hip trials was the Harris hip score (52.4%). At least 20 different outcome measures were used in the hip trials, and at least 14 different measures were used in knee trials. The primary outcome was identified in only 24% of trials.

Conclusion

We found extensive variation in outcome measures across trials and saw inconsistency across the components of the WHO ICF model. To improve interpretability, future work should determine whether consensus can be developed for a standardized set of outcome measures for hip and knee replacement trials.
α,α‐Diarylprolinol Ethers: New Tools for Functionalization of Carbonyl Compounds
Authors: Mielgo Antonia , Palomo Claudio
Published: May 2008

α,α‐Diaryl(dialkyl)prolinol ethers constitute a potent organocatalyst family which has been shown to be very general for a broad range of reactions involving enamine and iminium ion activation or a combination of both. The reactions are characterized by an efficient steric control approach and can lead to a variety of α‐, β‐, γ‐, and α,β‐functionalized carbonyl compounds with excellent stereocontrol. As a full expression of their catalytic activity, these compounds are also excellent promoters of elegant cascade processes and valuable catalysts in water‐compatible systems.
The effect of high strength static magnetic fields and ionizing radiation on gene expression and DNA damage in Caenorhabditis elegans
Authors: Kimura Takafumi , Takahashi Kohki , Suzuki Yoko , Konishi Yukinaga , Ota Yuta , Mori Chihiro , Ikenaga Takahiko , Takanami Takako , Saito Rumiko , Ichiishi Eiichiro , Awaji Satoshi , Watanabe Kazuo , Higashitani Atsushi
Published: May 2008

Magnetic resonance imaging with high static magnetic fields (SMFs) has become widely used for medical imaging purposes because SMFs cause fewer genotoxic side effects than ionizing radiation (IR). However, the effect of exposure to high SMFs on global transcription is little understood. We demonstrate that genes involved in motor activity, actin binding, cell adhesion, and cuticles are transiently and specifically induced following exposure to 3 or 5 T SMF in the experimental model metazoan Caenorhabditis elegans. In addition, transient induction of hsp12 family genes was observed after SMF exposure. The small‐heat shock protein gene hsp16 was also induced but to a much lesser extent, and the LacZ‐stained population of hsp‐16.1::lacZ transgenic worms did not significantly increase after exposure to SMFs with or without a second stressor, mild heat shock. Several genes encoding apoptotic cell‐death activators and secreted surface proteins were upregulated after IR, but were not induced by SMFs. Real‐time quantitative RT‐PCR analyses for 12 of these genes confirmed these expression differences between worms exposed to SMFs and IR. In contrast to IR, exposure to high SMFs did not induce DNA double‐strand breaks or germline cell apoptosis during meiosis. These results suggest that the response of C. elegans to high SMFs is unique and capable of adjustment during long exposure, and that this treatment may be less hazardous than other therapeutic tools. Bioelectromagnetics 29:605–614, 2008. © 2008 Wiley‐Liss, Inc.
Exposure of seeds to static magnetic field enhances germination and early growth characteristics in chickpea (Cicer arietinum L.)
Authors: Vashisth Ananta , Nagarajan Shantha
Published: May 2008

Seeds of chickpea (Cicer arietinum L.) were exposed in batches to static magnetic fields of strength from 0 to 250 mT in steps of 50 mT for 1–4 h in steps of 1 h for all fields. Results showed that magnetic field application enhanced seed performance in terms of laboratory germination, speed of germination, seedling length and seedling dry weight significantly compared to unexposed control. However, the response varied with field strength and duration of exposure without any particular trend. Among the various combinations of field strength and duration, 50 mT for 2 h, 100 mT for 1 h and 150 mT for 2 h exposures gave best results. Exposure of seeds to these three magnetic fields improved seed coat membrane integrity as it reduced the electrical conductivity of seed leachate. In soil, seeds exposed to these three treatments produced significantly increased seedling dry weights of 1‐month‐old plants. The root characteristics of the plants showed dramatic increase in root length, root surface area and root volume. The improved functional root parameters suggest that magnetically treated chickpea seeds may perform better under rainfed (un‐irrigated) conditions where there is a restrictive soil moisture regime. Bioelectromagnetics 29:571–578, 2008. © 2008 Wiley‐Liss, Inc.
Electrochemically Protected Copper(I)‐Catalyzed Azide–Alkyne Cycloaddition
Authors: Hong Vu , Udit Andrew K. , Evans Richard A. , Finn M. G.
Published: May 2008

The copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction has found broad application in myriad fields. For the most demanding applications that require high yields at low substrate concentrations, highly active but air‐sensitive copper complexes must be used. We describe here the use of an electrochemical potential to maintain catalysts in the active CuI oxidation state in the presence of air. This simple procedure efficiently achieves excellent yields of CuAAC products from both small‐molecule and protein substrates without the use of potentially damaging chemical reducing agents. A new water‐soluble carboxylated version of the popular tris(benzyltriazolylmethyl)amine (TBTA) ligand is also described. Cyclic voltammetry revealed reversible or quasi‐reversible electrochemical redox behavior of copper complexes of the TBTA derivative (2; E1/2=60 mV vs. Ag/AgCl), sulfonated bathophenanthroline (3; E1/2=−60 mV), and sulfonated tris(benzimidazoylmethyl)amine (4; E1/2≈−70 mV), and showed catalytic turnover to be rapid relative to the voltammetry time scale. Under the influence of a −200 mV potential that was established by using a reticulated vitreous carbon working electrode, CuSO4 and 3 formed a superior catalyst. Electrochemically protected bioconjugations in air were performed by using bacteriophage Qβ that was derivatized with azide moieties at surface lysine residues. Complete derivatization of more than 600 reactive sites per particle was demonstrated within 12 h of electrolysis with substoichiometric quantities of Cu⋅3.
Edge‐to‐Face CH/π Aromatic Interaction and Molecular Self‐Recognition in epi‐Cinchona‐Based Bifunctional Thiourea Organocatalysis
Authors: Tárkányi Gábor , Király Péter , Varga Szilárd , Vakulya Benedek , Soós Tibor
Published: May 2008

The impact of cooperativity between intermolecular interactions is demonstrated by the molecular self‐recognition properties of highly enantioselective epi‐cinchona bifunctional thiourea organocatalysts. Low‐temperature NMR experiments in inert solvents have revealed two sets of nonequivalent resonances in equal population for thiourea‐modified members of the epi‐quinine and epi‐quinidine families. In solution, the predominance of an asymmetric (C1) dimeric self‐assembly with noteworthy structural motifs became evident: simultaneous intra‐ and intermolecular thiourea hydrogen bonding and a CH/π interaction were observed. Both the stereochemical and the diverse conformational features of the system favor the observed quinoline T‐shaped aromatic π–π stacking interaction. The structure findings are supported by quantitative proton–proton distance data that were available from NOE buildup curves. The 3D structure of the dimeric assembly has been modeled in agreement with the H–H distance restraints. Owing to the geometrical preference associated with the dimerization process, the self‐assembled bifunctional system is interpreted as a charge‐transfer complex with the potential for catalyst self‐activation.
PGSE NMR Diffusion Overhauser Studies on [Ru(Cp*)(η6‐arene)][PF6], Plus a Variety of Transition‐Metal, Inorganic, and Organic Salts: An Overview of Ion Pairing in Dichloromethane
Authors: Moreno Aitor , Pregosin Paul S. , Veiros Luis F. , Albinati Alberto , Rizzato Silvia
Published: May 2008

PGSE diffusion, 19F, 1H HOESY and 13C NMR studies for a series of [Ru(Cp*)(η6‐arene)][PF6] (1) salts are presented. The solid‐state structure of [Ru(Cp*)(η6‐fluorobenzene)][PF6] (1 c) is reported. The extent of the ion pairing and the relative positions of the ions are shown to depend on the arene. For the solvent dichloromethane, new and literature PGSE data for PF6− salts of transition‐metal, inorganic, and organic salts are compared. Taken together, these new results show that the charge distribution and the ability of the anion to approach the positively charged positions (steric effects due to molecular shape) are the determining factors in deciding the amount of ion pairing. DFT calculations of the charges in four salts of type 1, as well as in a variety of other salts, using a natural population analysis (NPA), support this view. This represents the first attempt, using experimental data, to understand, correlate, and partially explain the various degrees of ion pairing in a widely different collection of salts.
Reactions of Nitroheteroarenes with Carbanions: Bridging Aromatic, Heteroaromatic, and Vinylic Electrophilicity
Authors: Seeliger Florian , Błażej Sylwia , Bernhardt Sebastian , Mąkosza Mieczysław , Mayr Herbert
Published: May 2008

The relative rate constants for the vicarious nucleophilic substitution (VNS) of the anion of chloromethyl phenyl sulfone (1−) with a variety of nitroheteroarenes, for example, nitropyridines, nitropyrroles, nitroimidazoles, 2‐nitrothiophene, and 4‐nitropyrazole, have been determined by competition experiments. It was shown that nitropyridines are approximately four orders of magnitude more reactive than nitrobenzene. Among the five‐membered heterocycles 2‐nitrothiophene is the most active followed by nitroimidazoles and 4‐nitropyrazole. Nitropyrroles are the least electrophilic nitroheteroarenes with reactivities comparable to nitrobenzene. Quantum chemically calculated methyl anion affinities (B3LYP/6–311G(d,p)//B3LYP/6–31G(d)) of the nitroarenes correlated only moderately with the partial relative rate constants. The correlation of these activities with the LUMO energies of nitroarenes is even worse. By measuring the second‐order rate constants of the addition of 1− to nitroarenes and to diethyl arylidenemalonates 10, it was possible to link the electrophilic reactivities of nitroheteroarenes with the comprehensive electrophilicity scale based on the linear‐free‐energy‐relationship log k(20 °C)=s(N + E).
The First Silicon‐Based Cationic Clathrate III with High Thermal Stability: Si172−xPxTey (x=2y, y>20)
Authors: Zaikina Julia V. , Kovnir Kirill A. , Haarmann Frank , Schnelle Walter , Burkhardt Ulrich , Borrmann Horst , Schwarz Ulrich , Grin Yuri , Shevelkov Andrei V.
Published: May 2008

A new representative of a very rare clathrate III family, Si130P42Te21, has been synthesized from the elements. It crystallizes in the tetragonal space group P42/mnm (no. 136) with the unit cell parameters a=19.2632(3) Å, c=10.0706(2) Å. Single crystal X‐ray diffraction and solid state 31P NMR revealed a non‐random distribution of phosphorus atoms over the framework positions. The crystal structure features a peculiar packing of large polyhedra Te@(Si/P)n never observed before for cationic clathrates. Despite the structural complexity, the composition of the novel clathrate Is in accordance with the Zintl rule, which was confirmed by a combination of optical metallography, scanning electron microscopy (SEM) and wavelength dispersive X‐ray spectroscopy (WDXS), as well as by diamagnetic and semiconducting behavior of the synthesized phase. Clathrate Si130P42Te21 exhibits the highest reported thermal stability for this class of materials, it decomposes at 1510 K. This opens new perspectives for the creation of clathrate‐based materials for high‐temperature applications.
Supramolecular Synthons on Surfaces: Controlling Dimensionality and Periodicity of Tetraarylporphyrin Assemblies by the Interplay of Cyano and Alkoxy Substituents
Authors: Wintjes Nikolai , Hornung Jens , Lobo‐Checa Jorge , Voigt Tobias , Samuely Tomáš , Thilgen Carlo , Stöhr Meike , Diederich François , Jung Thomas A.
Published: May 2008

The self‐assembly of three porphyrin derivatives was studied in detail on a Cu(111) substrate by means of scanning tunneling microscopy (STM). All derivatives have two 4‐cyanophenyl substituents in diagonally opposed meso‐positions of the porphyrin core, but differ in the nature of the other two meso‐alkoxyphenyl substituents. At coverages below 0.8 monolayers, two derivatives form molecular chains, which evolve into nanoporous networks at higher coverages. The third derivative self‐assembles directly into a nanoporous network without showing a one‐dimensional phase. The pore‐to‐pore distances for the three networks depend on the size and shape of the alkoxy substituents. All observed effects are explained by 1) different steric demands of the alkoxy residues, 2) apolar (mainly dispersion) interactions between the alkoxy chains, 3) polar bonding involving both cyanophenyl and alkoxyphenyl substituents, and 4) the entropy/enthalpy balance of the network formation.
Antidepressant drug‐induced stimulation of mouse hippocampal neurogenesis is age‐dependent and altered by early life stress
Authors: Navailles Sylvia , Hof Patrick R. , Schmauss Claudia
Published: May 2008

The continuous generation of new neurons in the adult hippocampus exhibits remarkable plasticity. Decreased neurogenesis is thought to underlie depression‐like behaviors, and increased neurogenesis is thought to occur following antidepressant drug treatment. Studies on different strains of mice, however, yielded contrasting results with regard to the link between behavioral modifications induced by antidepressant drugs or environmental enrichment and changes in adult hippocampal neurogenesis. Therefore, we conducted a comparative study on the inbred strains Balb/c and C57Bl/6 that differ substantially in emotionality, stress reactivity, and behavioral responses to chronic antidepressant drugs. Quantitative assessments of progenitor cell proliferation and immature neuronal differentiation in the dentate gyrus revealed that, despite significantly different basal proliferation rates between both strains, neither strain exhibited changes in adult neurogenesis after exposure to early life stress or adult chronic fluoxetine treatment. A stimulatory effect of fluoxetine on adult hippocampal neurogenesis was only detected when treatment was initiated during adolescence, and this effect was abolished in mice exposed to early life stress, a prominent risk factor for developing adult‐onset depression‐like behaviors. Thus, in both strains of mice neither adult fluoxetine treatment nor adolescent fluoxetine treatment following early life stress exposure increased the proliferation and early differentiation of adult neural progenitor cells. J. Comp. Neurol. 509:372–381, 2008. © 2008 Wiley‐Liss, Inc.
Dielectric and microhardness studies on L‐citrulline and L‐ascorbic acid admixture TGS crystals
Authors: Linet J. Mary , Priya S. Mary Navis , Dinakaran S. , Das S. Jerome
Published: May 2008

Single crystals of amino acid doped (L–citrulline, L‐ascorbic acid) triglycine sulphate were grown by slow evaporation technique. The lattice parameters and crystalline quality were confirmed by powder X‐ray diffraction studies. The presence of functional groups in the grown crystals was confirmed by Fourier transform infrared spectrum analysis. The dielectric studies were carried out to identify the phase transition temperature and the dielectric constant was found to be less for both the doped crystals than pure triglycine sulphate crystal. Micro hardness studies were carried out using Vickers pyramidal indentation technique at room temperature showed a decrease in hardness due to doping. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Controlled synthesis of selenium of different morphologies at room temperature
Authors: Ma Jianmin , Liu Xiaodi , Wu Yong , Peng Peng , Zheng Wenjun
Published: May 2008

A facile and convenient chemical precipitation route has been developed for the controlled growth of selenium nanowires and hierarchical microspheres at room temperature, with Na2SeO3 and hydrazine hydrate as starting materials in the presence of 1,2,3‐trimethylimidazolium tetrafluoroborate (tmimBF4). The surface morphology of microspheres can be tuned by adjusting the reaction media. The products were characterized by X‐ray powder diffraction (XRD) and scanning electron microscope (SEM). Possible formation mechanisms of selenium nanowires and microspheres are proposed, respectively. The influences of the nature of reaction media, agitation and tmimBF4 on the morphologies development were experimentally investigated and it was found that these factors were of great importance for the formation of Se morphologies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, characterization and crystal structure of a 2D Cd(II) complex with a 4,4'‐diazenediyldiphthalic acid ligand
Authors: Lu Lu , Wang Jun , Bai Jian‐Wei , Hou Yang , Yang Bin , Zhao Bao‐Zhong
Published: May 2008

An exploration of the cadmium‐L system under hydrothermal condition, has led to the isolation of a novel framework {[Cd(L)0.5(H2O)3]}n (1) (H4L = 4,4'‐diazenediyldiphthalic acid). Single‐crystal X‐ray analysis reveals that it crystallizes in the triclinic space group P‐1. a = 5.746(3) Å, b =6.526(4) Å, c = 14.701(8) Å, α=92.348(8), β = 99.622(6), γ=106.877(7)°. The CdII ions are linked into an extended 2‐D rectangle‐like structure via L ligands, which exhibits an attractive three‐connected honeycomb topological network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calorimetric and phase equilibria studies of the Ni–Sn–Bi system
Authors: Vassilev G. P. , Lilova K. I. , Gachon J.‐C.
Published: May 2008

The phase equilibria at 1273 K were investigated and an isothermal section of the Ni‐Sn‐Bi phase diagram was constructed. The phase boundaries are inclined to the Bi‐rich region that is agreement with phase equilibria at lower temperatures. The molar enthalpies of formation of liquid ternary Ni–Sn–Bi alloys have been determined at 833, 873 and 933 K by direct reaction calorimetry using pellets of 325 mesh powders of pure Ni, Sn and Bi. Measurements were performed with alloys containing from 0.05 to 0.10 mole fractions of nickel, and at ratios of tin and bismuth mole fractions XSn/XBi = 2.8, 1.2 and 0.43. The experimental calorimetric data were used to calculate a regular solutions parameter of the ternary liquid phase by means of two different thermodynamic data files. It was found that the Ni–Sn–Bi ternary liquid phase could be described as temperature independent ternary regular solution. The assessed values of the ternary interaction parameter are ‐280 J·mol–1 and 56 000 J·mol–1, depending on the binary parameters used. Enthalpies of formation of solid binary phases were measured, too. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomistic simulation of the self‐diffusion in Mg (001) surface
Authors: Zhang Jian‐Min , Yu Hua‐Zhi , Xu Ke‐Wei
Published: May 2008

Both the formation energies and the intra‐ and inter‐layer diffuse activation energies of a vacancy in the first six lattice planes of Mg (001) surface have been calculated by combining the modified analytical embedded‐atom method (MAEAM) with molecular dynamics (MD). The results show that the effect of the surface on the formation and migration of the vacancy is only down to the third‐layer. It is easer for a single vacancy to form and to migrate in the first layer. Furthermore, the vacancy in the second layer is favorable to migrate to the first layer. This is in agreement with the experimental results that the first layer has the highest concentration of the vacancy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A facile method to synthesize spherical PbS and their shape evolution process
Authors: Zhang Li , Yang Liangbao
Published: May 2008

PbS microspheres have been synthesized in large scale by a hydrothermal route, in which tungstosilicate acid (TSA) is used. The obtained PbS microspheres have been characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and X‐ray photoemission spectroscopy (XPS). Experiments show that Tungstosilicate acid plays an important role for the control of the morphology of PbS microstructures. An evolution process is described based on experimental facts. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and characterization of doped lithium aluminate nanocrystalline particles by sol‐gel method
Authors: Raj C. Justin , Lincoln M. B. , Das S. Jerome
Published: May 2008

Nanocrystalline particles of Co2+doped lithium aluminate (Co2+:LAO) and Ni2+‐doped lithium aluminate (Ni2+:LAO) were synthesized by sol–gel method. The crystalline nature and particle size of the samples were characterized by X‐ray diffraction analysis (XRD). The morphology and the presence Co2+ and Ni2+ in the synthesized samples were analyzed by scanning electron microscope (SEM) and energy dispersive X‐ray analysis (EDAX). The presences of functional groups in the samples were analyzed using FT‐IR analysis. The optical absorbance of the synthesized samples were observed using UV absorption spectral analysis. The frequency dependent dielectric behaviour of the synthesized nano materials was analyzed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Topology of Spin‐Crossover Polymers and Mutual Influence of Ligands
Authors: Le Guennic Boris , Matouzenko Galina S. , Borshch Serguei A.
Published: May 2008

Density functional quantum‐chemical calculations for mononuclear fragments, [FeII(pyim)2(bpy)]2+ [pyim = 2‐(2‐pyridyl)imidazole] and [FeII(aqin)2(bpy)]2+ (aqin = 8‐aminoquinoline), of two recently synthesized spin‐crossover compounds forming zigzag and linear coordination polymers, respectively, have been performed. The calculations suggest that the overall structure of the polymers is defined by the preference of the bidentate ligands for the cis or trans coordination mode, which in turn is determined by the character and efficiency of metal–ligand π‐interactions. This hypothesis is used to predict the structures of two other spin‐transition compounds, which have not been studied by X‐ray crystallography.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)