bluuebunny/crossref_metadata_2025 huggingface dataset:
Suicidality and Associated Risk Factors Among Lesbian, Gay, and Bisexual Compared to Heterosexual Austrian Adults
Authors: Plöderl Martin , Fartacek Reinhold
Published: January 2006

This is the first study in German‐speaking countries to compare the suicidality of lesbian, gay, and bisexual adults (n = 358) with matched heterosexual adults (n = 267). The former had significantly elevated incidences of current suicide ideation (28% vs. 13%) and lifetime suicide attempts defined in three ways (14% vs. 1% to 10% vs. 2%), including higher incidences for most suicidality‐related risk factors. Increased psychosocial stress and vulnerability is indicated, especially with respect to a lack of family support. Controlling for risk factors in multivariate analysis diminished the association of sexual orientation with current suicide ideation.
Siblings After Suicide—“The Forgotten Bereaved”
Authors: Dyregrov Kari , Dyregrov Atle
Published: January 2006

There is scarce research on “the forgotten bereaved”—the children and adolescents who lose a sibling by suicide. In this paper we explore their psychosocial situation and needs for assistance through a Norwegian nationwide study. The results show that particularly younger bereaved siblings are suffering from posttraumatic and grief reactions, depression, and anxiety. Most of the difficulties are not individual, but rather relational and social in nature, and largely contextually dependent. Necessary help is impeded due to the extraordinary experience leaving the siblings outside the circle of friends and parental grief community. A systematic outreach help program is presented.
A study on the metal binding of humic acid by multitracer technique
Authors: Chang Zheng , Ambe Shizuko , Takahashi Kazuya , Ambe Fumitoshi
Published: January 2006

A method combining radioactive ‘multitracer’ and dialysis techniques was developed to study the binding of multiple metal ions to humic acid (HA). Technical problems such as the leakage of small-molecule HA segment and the slow diffusion of metal ions through the dialysis membranes were examined. Under the condition of pH = 4.0,I= 0.100 M NaNO3, [MgII] = 0 M, or [MgII] = 0.500×10-3M, the interactions between Inogashira humic acid and metal ions (BeII, ScIII, ZnII, CoII, MnIIand SrII) were investigated by varying the metal concentrations in a wide range. It was found that as the concentrations of the trace metals are significantly smaller than that of HA, there are abundant binding sites available and there are no competition interactions between the trace metal ions of interest. Therefore, the stability constants for multiple metal ions binding onto humic substances can be obtained readily using the present method. The method is useful for quickly determining trace metal binding onto humic substances in environmental chemistry.
The structure of O-phospho-DL-threonine in potassium, sodium and ammonium environments
Authors: Bryndal Iwona , Lis Tadeusz
Published: January 2006

Interactions of O-phospho-DL-threonine (DL-PThr) in the different ionization states with potassium, sodium and ammonium cations have been studied on five crystals (denoted as I-V). In semipotassium salt of DL-PThr (I), the phosphate group adopts the nearly trans conformation, whereas in mono- and disodium salts (II and III) and in mono- and diammonium salts of DL-PThr (IV and V) the phosphate group is situated anticlinal to the rest of the molecule, showing its conformational flexibility depending on the crystal environment, where significant differences are observed in interactions of K+, Na+ and NH4
+ cations with PThr. The crystal packing in each of I-V is dominated by interactions between PThr moieties and the cations and hydrogen bond networks involving the phosphate, carboxyl, and amino groups of PThr moieties and water molecules. In crystal I, water molecules are not involved in potassium cation complexation. In crystals II and III, sodium cations show a preference for water molecules over PThr anions as ligands in coordination spheres. Especially in crystals I-III, water molecules are involved in very extensive networks of hydrogen-bond interactions.
Slip Calculation and Analysis for Four-wheel Drive Tractors
Authors: Szente Márk
Published: January 2006

The objective of the research of tires was to determine the dynamic rolling radius and to apply it to wheel slip calculations with special respect to vertical wheel load and to tire inflation pressure. It is typical of mechanical four-wheel drive tractors that there is a definite additional power in the tractor power chain. This additional power is dependent on the difference between the front wheel and rear wheel peripheral speeds. Further-more, the purpose was to determine the effect of additional slip on four-wheel drive tractors operated without drawbar pull. Experiments were performed on asphalt surfaces and fields. A new measurement method was developed, and a device was constructed for the implementation of three tractor wheel drive operational modes (four-wheel drive, rear-wheel drive and front-wheel drive). As the result of the experiments, a relationship was found to describe the dynamic rolling radius for low-profile radial tires tested on rigid road surfaces. On this basis, the classical slip calculation method was modified. This phenomenon appears only on hard roads and soil surfaces with high adhesion coefficients and only within the low drawbar pull range.
Prediction of Dry Matter and Crude Protein Content in Fresh Grass Silage by Near Infrared Spectroscopy
Authors: Vranić Marina , Knežević Mladen , Seregély Zsolt , Bošnjak Krešimir , Leto Josip , Perčulija Goran
Published: January 2006

Intensive livestock feeding requires constant monitoring of diet composition to ensure a consistent level of milk or meat production. A rapid analysis of fresh grass silage samples for dry matter (DM) and crude protein (CP) content would provide basic, rapid information what would permit decision to be made regarding the need to supplement the diet. The aim of the present study was to determine dry matter (DM) and crude protein (CP) content in fresh grass silage samples by NIR spectroscopy. Crude protein content can be expressed as g per kg dry matter (g kg-1 DM) or as per cent of fresh weight (% FW). Near-infrared reflectance spectra were recorded for 103 fresh grass silage samples. Laboratory analysis of DM and CP were determined for these samples. MLR, PCR and PLS techniques were used for data modelling to determine the optimum models for predicting each of the chemical constituents. It was concluded that the PLS method was superior to the PCR and MLR methods for DM and CP prediction in fresh grass silage samples, while MLR showed a promising possibility to determine the CP content using only two spectral values measured at two “characteristic”wavelengths.
Effects of Non-uniform Kernel Moisture Content on Moisture Measurement of Corn
Authors: Gillay Bíborka , B. Funk David
Published: January 2006

The price paid for corn is usually based on 15.0 or 15.5 percent moisture content. However, corn must be dried below 13 percent moisture to ensure safe storage for a year or more. In the U.S., such stored corn cannot be directly remoistened before selling it, but it can be mixed with moist new-crop corn. Accurate moisture measurement of mixtures of dry and moist corn is important to permit adjustment of blending ratios to maximize profitability, but grain moisture meters are less accurate for mixtures of wet and dry grain. This research evaluated the differences between dielectric-type moisture meter results for mixed and equilibrated corn samples at different moisture levels and different measurement frequencies. Equilibrated grain samples tended to give lower moisture results than recently mixed grain samples - especially in the 1 to 10 MHz region. These differences permitted detection of mixtures by using moisture measurements at two frequencies.
Predators impairing the natural biological control of parasitoids
Authors: Reis Jr Ronaldo , Souza Og De , Vilela Evaldo F.
Published: January 2006

A well known case of ineffective natural biological control: the puzzling coexistence of the coffee leaf miner, Leucoptera coffeellum (Guérin-Mèneville), and its natural enemies was analyzed. Despite being a suitable prey to eight parasitoid species and three wasp species, all occurring simultaneously, the coffee leaf miner too often presents populations far above the damaging level for the coffee plantation. It is demonstrated that predatory wasps and parasitoids interact negatively, possibly because predatory wasps kill parasitized miner's larvae. In doing so, predatory wasps indirectly kill parasitoids, thereby impairing the efficacy of the natural biological control. It is warned that biological control programs should be based on knowledge of food web interactions, rather than simply on strategies involving introduction of exotic natural enemies.
Temporal variability and progression of Neozygites sp. (Zygomycetes: Entomophthorales) in populations of Mononychellus tanajoa (Bondar) (Acari: Tetranychidae)
Authors: Delalibera Jr. Italo , Moraes Gilberto J. de , Lapointe Stephen L. , Silva Carlos A. D. da , Tamai Marco A.
Published: January 2006

The objective of this study was to characterize epizootics of Neozygites sp. by investigating the relationship between the pathogen, the host, Mononychellus tanajoa (Bondar) (Cassava green mite = CGM), and climatic factors. Epizootics were studied from March through October 1994 in nine cassava fields at Piritiba, state of Bahia, Brazil. In all fields the pathogen appeared when CGM density was moderate to high. Infected CGM were first detected in northwestern fields, with an apparent progression to the southeast. The onset of the epizootic in the earliest field was observed 23 days prior to the onset of the epizootic in the latest field. During the epizootic phase of most fields (late May to late June), daily mean RH ranged from 70% to 79% and daily mean temperature ranged between 21.1°C and 24.3°C. Disease progression within CGM populations was documented in two of the nine fields. In the field where the slower spread of the pathogen was observed, the proportion of area with infected CGM increased from 14% to 100% in 14 days. Neozygites sp. was detected in higher proportions in plots with the highest levels of CGM and in greater abundance on mites collected from apical leaves as compared with median leaves. Resting spores of Neozygites sp. were recovered during June and July, but during the remaining period, infected mites contained only hyphal bodies.
Antibiosis effects of wild bean lines containing arcelin on Bemisia tabaci (Genn.) biotype B (Homoptera: Aleyrodidae)
Authors: Oriani Maria A. de G. , Lara Fernando M.
Published: January 2006

The biology of Bemisia tabaci biotype B (Genn.) on bean (Phaseolus vulgaris L.) genotypes containing arcelin in the seeds was evaluated. Also, biochemical screening of seeds and leaves material of these genotypes were carried out in order to verify if traces of arcelin could be found in its leaves. The tests were conducted under greenhouse conditions, in the dry and wet seasons, with the following genotypes: ARC 3s, ARC 5s (wild genotypes containing arcelin in the seeds); ARC 1, ARC 2, ARC 3, ARC 4 (near isogenic lines containing arcelin in the seeds - EMBRAPA) and Porrillo 70, Bolinha, IAPAR MD 808 (commercial genotypes without arcelin). The wild genotypes, ARC 3s and ARC 5s, showed high levels of antibiosis resistance type, mainly for ARC 5s which presented the highest nymphs mortality rates, approximately 90%. Also, the longest development time for nymphs fed on ARC 5s genotype suggest antibiosis and/or feeding nonpreference resistance type. The wild genotype resistance is not related with arcelin presence in the seeds, since no trace of this protein was found in its leaves.
Oligosaccharides in the honeydew of Coccoidea scale insects: Coccus hesperidum L. and a new Stigmacoccus sp. in Brazil
Authors: Bogo Amauri , Mantle Peter
Published: January 2006

Analysis of the honeydew from an as yet undescribed, though distinctive, Brazilian Stigmacoccus sp. (near S. asper Hempel) by paper chromatography, Fast atom bombardment (FAB-MS) and Gas chromatography-mass spectrometry (GC-MS) identified fructose and glucose as monosaccharides and sucrose, maltose, trehalulose, trehalose and a hexose-hexitol as disaccharides. Erlose and glucosyl erlose have been identified as the tri- and tetra-saccharides in Stigmacoccus sp. and characterised for the first time in scale insects by modern techniques of linkage analysis. The same erlose oligosaccharides were recognised in honeydew of the common scale insect Coccus hesperidum L., together with the pentamer of this series, maltosyl erlose, therefore recognising that specific metabolic transformations of sugars into this oligomeric series occur rather widely in Coccoidea scale insects.
Na+/H+ Exchanger Regulatory Factor-1 Is a Hematopoietic Ligand for a Subset of the CD34 Family of Stem Cell Surface Proteins
Authors: Tan Poh C. , Furness Sebastian G.B. , Merkens Helen , Lin Shujun , McCoy Marcia L. , Roskelley Calvin D. , Kast Jürgen , McNagny Kelly M.
Published: January 2006

CD34 and its relatives, podocalyxin and endoglycan, comprise a family of surface sialomucins expressed by hematopoietic stem/progenitor cells and vascular endothelia. Recent data suggest that they serve as either pro- or antiadhesion molecules depending on their cellular context and their post-translational modifications. In addition, their ability to function as blockers of adhesion may be further regulated by their subcellular localization in membrane microdomains via activation-dependent linkage with the actin cytoskeleton. To gain further insights into the function and regulation of CD34-type molecules, we sought to identify the intracellular ligands that govern their localization. Using both genetic and biochemical approaches, we have identified the Na+/H+ exchanger regulatory factor-1 (NHERF-1) as a selective ligand for podocalyxin and endoglycan but not for the closely related CD34. Furthermore, we show that NHERF-1 is expressed by all c-kit+ /lineage marker− /Sca-1+ cells, which are known to express podocalyxin and have long-term repopulating abilities. Finally, we show that these proteins relocalize and colocalize in response to cytokine signaling. The results suggest that this cytosolic adaptor protein may be important for mobilization of CD34-type proteins in the plasma membrane and may thereby regulate their ability to block or enhance hematopoietic cell adhesion.
Properties of Nanocrystalline CuCr50 Contact Material
Authors: Zhang C. , Yang Z. , Wang Y. , Ding B.
Published: January 2006

The CuCr50 alloy with grain size less than 50nm was prepared by mechanical alloy and hot pressing technique. The cathode erosion rate of nanocrystalline CuCr50 is much lower than that of microcrystalline CuCr50 and the breakdown strength of nanocrystalline CuCr50 is slightly higher than that of microcrystalline CuCr50. The main reason is that the melting on the surface of nanocrystaline cathode is slighter than that on the surface of microcrystalline cathode.
Experimental Studies of Phase Transformations in a Carbon Containing Ti‐45Al‐7.5Nb Alloy and Related Thermodynamic Simulations
Authors: Chladil H. F. , Clemens H. , Leitner H. , Bartels A. , Gerling R. , Marketz W. T.
Published: January 2006

Phase transformations and phase transition temperatures in several Nb‐rich γ‐TiAl based alloys were investigated experimentally and compared to thermodynamic simulations. The present study combines scanning electron microscopy and differential‐scanning‐calorimetry for the characterisation of the prevailing phases and phase transformations. Thermodynamic simulation based on the CALPHAD method was used for predict phase stabilities. The results from experiments on a variety of γ‐TiAl based alloys are compared to thermodynamic calculations. Finally, the influence of carbon on the transition temperatures is presented.
Self‐Organized Nanostructures in Hard Ceramic Coatings
Authors: Mayrhofer P. H. , Mitterer C. , Clemens H.
Published: January 2006

Nanostructures have attracted increasing interest in modern development of hard coatings for wear‐resistant applications. In plasma‐assisted vapor deposited thin films, nanostructures can evolve during growth or a post‐deposition annealing treatment. In this review we demonstrate, using TiB2.4, TiN–TiB2, Ti0.34Al0.66N, and Ti(N,B) as model‐coatings, the development of nanostructures and its influence on the mechanical properties of ceramic thin films. For TiB2.4 and TiN–TiB2 a two‐dimensional and three‐dimensional nanostructure, respectively, organizes itself during growth by segregation driven processes. Growth of Ti0.34Al0.66N and Ti(N,B) results in the formation of a supersaturated TiN based phase, which tends to decompose into its stable constituents during post‐deposition annealing via the formation of nm‐sized domains. As the hardness of a material is determined by resistance to bond distortion and dislocation formation and motion, which depend on the amount and constitution of obstacles provided, there is a direct relation between hardness and nanostructure.
Laser Processing of Advanced Bioceramics
Authors: Narayan R. J. , Jin C. , Doraiswamy A. , Mihailescu I. N. , Jelinek M. , Ovsianikov A. , Chichkov B. , Chrisey D. B.
Published: January 2006

In this article, laser processing of diamondlike carbon‐metal nanocomposite films, hydroxyapatite‐osteoblast composites, and Ormocer® microdevices for medical applications is described. Pulsed laser deposition has been used to process diamondlike carbon‐silver‐platinum nanocomposite films that provide hardness, wear resistance, corrosion resistance, and antimicrobial functionalities to cardiovascular, orthopaedic, biosensor, and MEMS devices. Laser direct writing has been used for fabricating integrated cell‐scaffold structures. Two photon induced polymerization has been used to create Ormocer® tissue engineering scaffolds and microneedles with unique geometries. Pulsed laser deposition, laser direct write, and two photon induced polymerization techniques may provide medical engineers with advanced biomaterials that possess unique structures and functionalities.
Mechanical and Morphological Properties of Cellulose Fibril Reinforced Nanocomposites
Authors: Zimmermann T. , Pöhler E. , Schwaller P.
Published: January 2006

The Modulus of Elasticity (MOE) and the hardness of fibril reinforced hydroxypropyl cellulose films were determined by nanoindentation. In addition, the fibril alignment in the composites was analysed by Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The results show that the formation of fibril networks is of great importance for the mechanical properties of the nanocomposites.
Mechanical Behavior of Multilayered Nanoscale Metal‐Ceramic Composites
Authors: Deng X. , Chawla N. , Chawla K. K. , Koopman M. , Chu J. P.
Published: January 2006

Single and multilayered structures at nano‐length scale are very attractive materials due to their high strength, toughness, and wear resistance relative to conventional laminated composites. In this study, single layered Al, SiC, and multilayered Al/SiC composites were synthesized by DC/RF magnetron sputtering. The microstructure of the multilayered structures was characterized by scanning electron microscopy (SEM). The elastic and plastic behavior of single and multilayered materials was investigated by nanoindentation and tensile testing. For nanoindentation, an analytical model was employed to subtract the contribution of the Si substrate, in order to extract the true modulus of the films. Finite element simulations were employed to confirm the analytical predictions and to investigate the anisotropic elastic behavior of the multilayered composite. It was concluded that while indentation provides reasonable Young's modulus and hardness values in monolithic layers, it does not provide the true modulus of the multilayered materials because of their inherent anisotropy.
Arrays of Electroplated Multilayered Co/Cu Nanowires with Controlled Magnetic Anisotropy
Authors: Pirota K. R. , Vazquez M.
Published: January 2006

The controlled production of arrays of nanowires exhibiting outstanding characteristics is recently attracting much interest owing to their applications in a number of emerging technologies related with multifunctional biosensor applications, controlled optomagnetic response, magnetic storage, magnetotransport, or catalytic performance. While nanolitography methodes require sophisticated experimental facilities, an alternative technique that makes use of much simpler conventional anodization and electrodeposition methods in the fabrication of metallic nanowires arrays is increasingly employed. This method allows the preparation of arrays of highly‐ordered nanopores induced by anodisation, and its filling with metallic elements by electrodepositon.
Silicon Carbide Foams by Polyurethane Replica Technique
Authors: Mouazer R. , Mullens S. , Thijs I. , Luyten J. , Buekenhoudt A.
Published: January 2006

This paper describes the process of polyurethane replica technique for fabricating highly porous SiC ceramic foams using gelatin as gelling agent. Characterization of the porous ceramics have been performed by 3‐point‐bending strength, gas permeability and electrical conductivity measurements.
Lightweight Potential of Novel Cellular Spherical Composites
Authors: Klaus H. , Huber O. , Kuhn G.
Published: January 2006

A genuine cellular spherical composite which is a syntactic foam with cellular spheres is presented. Numerical and experimental investigations show the high lightweight potential of the cellular spherical composite in the elastic range in comparison with a conventional cellular solid with equal weight. A modified Voigt‐Reuss mixing rule is proposed to describe the elastic behaviour of the composite under compression load.
Materials Selection Process for Compound‐Extruded Aluminium Matrix Composites
Authors: Weidenmann K. A. , Fleck C. , Schulze V. , Löhe D.
Published: January 2006

Compound extrusion is a near‐net‐shape process allowing for the rapid and flexible in‐line production of unidirectionally‐reinforced profiles. Regarding the use of this technology for the production of reinforced lightweight profiles for structural applications, no materials combination has yet been systematically assessed or examined since the first investigations on compound conductor rails starting in the 1970s. On this account, a materials selection process respecting the compound extrusion demands is mandatory.
Aspects of Quality Assurance in a Thermodynamic Mg Alloy Database
Authors: Schmid‐Fetzer R. , Janz A. , Gröbner J. , Ohno M.
Published: January 2006

Quality assurance is a major concern for large thermodynamic databases. Examples for standard tests on phase diagrams, thermodynamic functions or parameters will be shown that are of practical use in checking consistency and plausibility. The typical end user, applying the database to a real multicomponent material or process, will generally not have sufficient time, resources, and experience to perform the quality check himself.
Piezoelectric Polyethylene Terephthalate (PETP) Foams – Specifically Designed and Prepared Ferroelectret Films
Authors: Wegener M. , Wirges W. , Gerhard‐Multhaupt R.
Published: January 2006

The ferroic and electroactive properties of the recently identified ferroelectrets are based on the quasi‐permanent internal electric charging of the cellular structure in polymer foams. Drawing on the wealth of expertise and insight that was obtained on cellular polypropylene (PP) and in particular on structure‐property relations that were established for PP, foamed polyethylene terephthalate (PETP) is for the first time demonstrated as a possible alternative ferroelectret with a significantly different range of applications‐relevant properties than PP.
Straining Nanocrystals in Microscope: Grain Growth or Rotation?
Authors: Li H.
Published: January 2006

This paper aims to provide the scientific analysis on a reported result regarding the in‐situ straining nanocrystalline pure nickel in microscope. The close examinations strongly suggest that the grain‐boundary activities, such as grain rotation, are very active under severe plastic deformation. The Figure shows a low‐angle grain boundary consisting of four dislocations.
Corrosion of AZ 91 Secondary Magnesium Alloy
Authors: Scharf C. , Ditze A. , Shkurankov A. , Morales E. , Blawert C. , Dietzel W. , Kainer K. U.
Published: January 2006

Recycling of magnesium alloys produces scrap metal with high contents of copper, nickel and silicon. These impurities are not to be removed by remelting. The products thus have corrosion rates which lie well above those of high purity magnesium alloys. The aim is improving the corrosion properties of contaminated alloys, so that they can be used as secondary alloys in structural parts in spite of their high concentration of impurities.
Cover Picture: Laser Processing of Advanced Bioceramics (Adv. Eng. Mater. 12/2005)
Authors: Narayan R. J. , Jin C. , Doraiswamy A. , Mihailescu I. N. , Jelinek M. , Ovsianikov A. , Chichkov B. , Chrisey D. B.
Published: January 2006

In this article, laser processing of diamondlike carbon‐metal nanocomposite films, hydroxyapatite‐osteoblast composites, and Ormocer® microdevices for medical applications is described. Pulsed laser deposition has been used to process diamondlike carbon‐silver‐platinum nanocomposite films that provide hardness, wear resistance, corrosion resistance, and antimicrobial functionalities to cardiovascular, orthopaedic, biosensor, and MEMS devices. Laser direct writing has been used for fabricating integrated cell‐scaffold structures. Two photon induced polymerization has been used to create Ormocer® tissue engineering scaffolds and microneedles with unique geometries. Pulsed laser deposition, laser direct write, and two photon induced polymerization techniques may provide medical engineers with advanced biomaterials that possess unique structures and functionalities.
General friction theory viscosity model for the PC‐SAFT equation of state
Authors: Quiñones‐Cisneros Sergio E. , Zéberg‐Mikkelsen Claus K. , Fernández Josefa , García Josefa
Published: January 2006

In this work, a general f‐theory viscosity model based on the perturbed‐chain statistical associating fluid theory (PC‐SAFT) equation of state (EoS) has been developed for the description of the viscosity behavior of the normal alkanes family (from methane to n‐octadecane). This general f‐theory model has been shown to provide satisfactory results for the modeling of the viscosity of the normal alkanes as well as carbon dioxide and nitrogen over wide ranges of temperatures and up to 100 MPa. In addition, using simple mixing rules, an evaluation of the model performance has been carried out for several n‐alkane and carbon dioxide + n‐alkane mixtures over wide ranges of temperature and pressure. The chosen mixing rules provide good mixture viscosity prediction, close to or within experimental uncertainty, which is satisfactory for most applications (industrial and research). Further, the combination of the PC‐SAFT EoS with the f‐theory adds one more thermophysical property to the list of properties for which this model already delivers an improved representation, making the application potential for the PC‐SAFT EoS even wider. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Real‐time estimation of food defrosting by software sensors
Authors: Akkari E. , Chevallier S. , Boillereaux L.
Published: January 2006

Software sensors (or observers) are especially useful when the state vector of a system cannot be measured. Widely employed for bioprocesses, they estimate the state variables from available measurements, which are functions of one or several state variables, provided that the observability property is checked. In food defrosting, an important challenge is to know the spread of the melting front inside the product, without any invasive measurement. The solution proposed in this paper is based on the design of software sensors able to estimate, from a superficial temperature measurement, the temperature distribution in the product, in real time, and consequently making it possible to determine the melting zone. The proposed solutions are, first, an extended Kalman Filter and, second, switched reduced Luenberger observers. The results are illustrated during the experimental thawing of a block of tylose in forced convection. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Cortical network for representing the teeth and tongue in primates
Authors: Kaas Jon H. , Qi Hui‐Xin , Iyengar Soumya
Published: January 2006

Sensory information from the tongue and teeth is used to evaluate and distinguish food and nonfood items in the mouth, reject some and masticate and swallow others. While it is known that primates have a complex array of 10 or more somatosensory areas that contribute to the analysis of sensory information from the hand, less is known about what cortical areas are involved in processing information from receptors of the tongue and teeth. The tongue contains taste receptors, as well as mechanoreceptors. Afferents from taste receptors and mechanoreceptors of the tongue access different ascending systems in the brainstem. However, it is uncertain how these two sources of information are processed in cortex. Here the parts of somatosensory areas 3b, 3a, and presumptive 1 that represent the mechanoreceptors of the teeth and tongue are identified, and evidence is presented that the representations of the tongue also get information from the taste nucleus of the thalamus, VPMpc. As areas 3b, 3a, and 1 project to other areas of somatosensory cortex, and those areas to additional areas, some or all of the currently defined somatosensory areas of cortex may be involved in processing gustatory, as well as tactile, information from the tongue and thus have a role in the biologically important function of evaluating food in the mouth. © 2006 Wiley‐Liss, Inc.
Imaging, anatomical, and molecular analysis of callosal formation in the developing human fetal brain
Authors: Ren Tianbo , Anderson Aurora , Shen Wei‐Bin , Huang Hao , Plachez Celine , Zhang Jiangyang , Mori Susumu , Kinsman Stephen L. , Richards Linda J.
Published: January 2006

A complex set of axonal guidance mechanisms are utilized by axons to locate and innervate their targets. In the developing mouse forebrain, we previously described several midline glial populations as well as various guidance molecules that regulate the formation of the corpus callosum. Since agenesis of the corpus callosum is associated with over 50 different human congenital syndromes, we wanted to investigate whether these same mechanisms also operate during human callosal development. Here we analyze midline glial and commissural development in human fetal brains ranging from 13 to 20 weeks of gestation using both diffusion tensor magnetic resonance imaging and immunohistochemistry. Through our combined radiological and histological studies, we demonstrate the morphological development of multiple forebrain commissures/decussations, including the corpus callosum, anterior commissure, hippocampal commissure, and the optic chiasm. Histological analyses demonstrated that all the midline glial populations previously described in mouse, as well as structures analogous to the subcallosal sling and cingulate pioneering axons, that mediate callosal axon guidance in mouse, are also present during human brain development. Finally, by Northern blot analysis, we have identified that molecules involved in mouse callosal development, including Slit, Robo, Netrin1, DCC, Nfia, Emx1, and GAP‐43, are all expressed in human fetal brain. These data suggest that similar mechanisms and molecules required for midline commissure formation operate during both mouse and human brain development. Thus, the mouse is an excellent model system for studying normal and pathological commissural formation in human brain development. © 2006 Wiley‐Liss, Inc.
Whisker maps in marsupials: Nerve lesions and critical periods
Authors: Waite Phil M.E. , Gorrie Catherine A. , Herath Nimali P. , Marotte Lauren R.
Published: January 2006

In the wallaby, whisker‐related patterns develop over a protracted period of postnatal maturation in the pouch. Afferents arrive simultaneously in the thalamus and cortex from postnatal day (P) 15. Whisker‐related patterns are first seen in the thalamus at P50 and are well formed by P73, before cortical patterns first appear (P75) or are well developed (P85). This study used the slow developmental sequence and accessibility of the pouch young to investigate the effect of nerve lesions before afferent arrival, or at times when thalamic patterns are obvious but cortical patterns not yet formed. The left infraorbital nerve supplying the whiskers was cut at P0–93 and animals were perfused at P112–123. Sections through the thalamus (horizontal plane) and cortex (tangential) were reacted for cytochrome oxidase to visualize whisker‐related patterns. Lesions of the nerve at P2–5, before innervation of the thalamus or cortex, resulted in an absence of patterns at both levels. Lesions from P66–77 also disrupted thalamic and cortical patterns, despite the fact that thalamic patterns are normally well established by P73. Lesions from P82–93 resulted in normal thalamic and cortical patterns. Thus, despite the wallaby having clearly separated times for the development of patterns at different levels of the pathway, these results suggest a single critical period for the thalamus and cortex, coincident with the maturation of the cortical pattern. Possible mechanisms underpinning this critical period could include dependence of the thalamic pattern on corticothalamic activity or peripheral signals to allow consolidation of thalamic barreloids. © 2006 Wiley‐Liss, Inc.
Connecting thalamus and cortex: The role of ephrins
Authors: Uziel Daniela , Garcez Patricia , Lent Roberto , Peuckert Christiane , Niehage Ronny , Weth Franco , Bolz Jürgen
Published: January 2006

The complex task of wiring up the brain during embryonic development is achieved by a multitude of guidance signals acting in complex combinations to drive growing axons to their proper targets. The somatosensory system provides an extensively studied model system featuring many universal mechanisms of neural development. In rodents, it constitutes an important model to study how precise topographic connections are achieved. Recent evidence suggests that the Eph/ephrin family of guidance molecules is of pivotal importance for the development of the somatosensory system. Members of Eph/ephrin family are thought to be involved in the global presorting of thalamic axons projecting to the cortex, in labeling specific cortical areas for innervation, in providing topographic cues within the target area, and in distinguishing cortical layers for intracortical wiring. The Eph/ephrin system also seems to contribute to the formation of specific corticothalamic feedback projections. So far, the functions of only a few members of the Eph/ephrin family have been examined, but expression analysis indicates complex combinatorial effects of these signaling molecules. Understanding the Eph/ephrin wiring code is expected to yield new insights into the development and plasticity of brain circuits involved in higher functions. © 2006 Wiley‐Liss, Inc.
Evaluating China's university library Web sites using correspondence analysis
Authors: Shen Xiangxing , Li Dongmin , Shen Chong
Published: January 2006

In recent years, many evaluations of Web sites have been conducted, and relevant researches have also been carried out in academic circles. Correspondence analysis is introduced in this paper to evaluate university library Web sites through building a correspondence analysis model. This paper gives suggestions as to how to construct university library Web sites based on analysis and summary of evaluation results, in a bid to strengthen the construction of university library Web sites.
Understanding consumer trust in Internet shopping: A multidisciplinary approach
Authors: Cheung Christy M.K. , Lee Matthew K.O.
Published: January 2006

The importance of trust in building and maintaining consumer relationships in the online environment is widely accepted in the Information Systems literature. A key challenge for researchers is to identify antecedent variables that engender consumer trust in Internet shopping. This paper adopts a multidisciplinary approach and develops an integrative model of consumer trust in Internet shopping through synthesizing the three diverse trust literatures. The social psychological perspective guides us to include perceived trustworthiness of Internet merchants as the key determinant of consumer trust in Internet shopping. The sociological viewpoint suggests the inclusion of legal framework and third‐party recognition in the research model. The views of personality theorists postulate a direct effect of propensity to trust on consumer trust in Internet shopping. The results of this study provide strong support for the research model and research hypotheses, and the high explanatory power illustrates the complementarity of the three streams of research on trust. This paper contributes to the conceptual and empirical understanding of consumer trust in Internet shopping. Implications of this study are noteworthy for both researchers and practitioners.
How much of it is real? Analysis of paid placement in Web search engine results
Authors: Nicholson Scott , Sierra Tito , Eseryel U. Yeliz , Park Ji‐Hong , Barkow Philip , Pozo Erika J. , Ward Jane
Published: January 2006

Most Web search tools integrate sponsored results with results from their internal editorial database in providing results to users. The goal of this research is to get a better idea of how much of the screen real estate displays “real” editorial results as compared to sponsored results. The overall average results are that 40% of all results presented on the first screen are “real” results, and when the entire first Web page is considered, 67% of the results are nonsponsored results. For general search tools such as Google, 56% of the first screen and 82% of the first Web page contain nonsponsored results. Other results include that query structure makes a significant difference in the percentage of nonsponsored results returned by a search. Similarly, the topic of the query also can have a significant effect on the percentage of sponsored results displayed by most Web search tools.
Query expansion behavior within a thesaurus‐enhanced search environment: A user‐centered evaluation
Authors: Shiri Ali , Revie Crawford
Published: January 2006

The study reported here investigated the query expansion behavior of end‐users interacting with a thesaurus‐enhanced search system on the Web. Two groups, namely academic staff and postgraduate students, were recruited into this study. Data were collected from 90 searches performed by 30 users using the OVID interface to the CAB abstracts database. Data‐gathering techniques included questionnaires, screen capturing software, and interviews. The results presented here relate to issues of search‐topic and search‐term characteristics, number and types of expanded queries, usefulness of thesaurus terms, and behavioral differences between academic staff and postgraduate students in their interaction. The key conclusions drawn were that (a) academic staff chose more narrow and synonymous terms than did postgraduate students, who generally selected broader and related terms; (b) topic complexity affected users' interaction with the thesaurus in that complex topics required more query expansion and search term selection; (c) users' prior topic‐search experience appeared to have a significant effect on their selection and evaluation of thesaurus terms; (d) in 50% of the searches where additional terms were suggested from the thesaurus, users stated that they had not been aware of the terms at the beginning of the search; this observation was particularly noticeable in the case of postgraduate students.
Categorization‐driven cross‐language retrieval of medical information
Authors: Freitas‐Junior Hermes R. , Ribeiro‐Neto Berthier , Vale Rodrigo F. , Laender Alberto H. F. , Lima Luciano R. S.
Published: January 2006

The Web has become a large repository of documents (or pages) written in many different languages. In this context, traditional information retrieval (IR) techniques cannot be used whenever the user query and the documents being retrieved are in different languages. To address this problem, new cross‐language information retrieval (CLIR) techniques have been proposed. In this work, we describe a method for cross‐language retrieval of medical information. This method combines query terms and related medical concepts obtained automatically through a categorization procedure. The medical concepts are used to create a linguistic abstraction that allows retrieval of information in a language‐independent way, minimizing linguistic problems such as polysemy. To evaluate our method, we carried out experiments using the OHSUMED test collection, whose documents are written in English, with queries expressed in Portuguese, Spanish, and French. The results indicate that our cross‐language retrieval method is as effective as a standard vector space model algorithm operating on queries and documents in the same language. Further, our results are better than previous results in the literature.
Stabilization of unusual structures in peptides using α,β‐dehydrophenylalanine: Crystal and solution structures of Boc–Pro–ΔPhe–Val–ΔPhe–Ala–OMe and Boc–Pro–ΔPhe–Gly–ΔPhe–Ala–OMe
Authors: Mathur Puniti , Ramagopal U. A. , Ramakumar S. , Jagannathan N. R. , Chauhan V. S.
Published: January 2006

The structures of two dehydropentapeptides, Boc–Pro–ΔPhe–Val–ΔPhe–Ala–OMe (I) and Boc–Pro–ΔPhe–Gly–ΔPhe–Ala–OMe (II) (Boc: t‐butoxycarbonyl), have been determined by nuclear magnetic resonance (NMR), circular dichroism (CD), and X‐ray crystallographic studies. The peptide I assumes a S‐shaped flat β‐bend structure, characterized by two partially overlapping type II β‐bends and absence of a second 1 ← 4 (N4H · · · O1′) intramolecular hydrogen bond. This is in contrast to the generally observed 310‐helical conformation in peptides with ΔPhe at alternate positions. This report describes the novel conformation assumed by peptide I and compares it with that of the conserved tip of the V3 loop of the HIV‐1 envelope glycoprotein gp120 (sequence, G:P319 to F:P324, PDB code 1ACY). The tip of the V3 loop also assumes a S‐shaped conformation with Arg:P322, making an intramolecular side‐chain–backbone interaction with the carbonyl oxygen of Gly:P319. Interestingly, in peptide I, CγHVal3 makes a similar side‐chain–backbone CH · · · O hydrogen bond with the carbonyl oxygen of the Boc group. The observed overall similarity indicates the possible use of the peptide as a viral antagonist or synthetic antigen. Peptide II adopts a unique turn followed by a 310‐helix. Both peptides I and II are classical examples of stabilization of unusual structures in oligopeptides. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 298–309, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Characterization of β‐turn and Asx‐turns mimicry in a model peptide: Stabilization via CH · · · O interaction
Authors: Thakur A. K. , Kishore R.
Published: January 2006

The chemical synthesis and single‐crystal X‐ray diffraction analysis of a model peptide, Boc–Thr–Thr–NH2 (1) comprised of proteinogenic residues bearing an amphiphilic Cβ‐stereogenic center, has been described. Interestingly, the analysis of its molecular structure revealed the existence of a distinct conformation that mimics a typical β‐turn and Asx‐turns, i.e., the two Thr residues occupy the left‐ and right‐corner positions. The main‐chain torsion angles of the N‐ and C‐terminal residues i.e., semiextended: ϕ = −68.9°, ψ = 128.6°; semifolded: ϕ = −138.1°, ψ = 2.5° conformations, respectively, in conjunction with a gauche− disposition of the obligatory C‐terminus Thr CγH3 group, characterize the occurrence of the newly described β‐turn‐ and Asx‐turns‐like topology. The preferred molecular structure is suggested to be stabilized by an effective nonconventional main‐chain to side‐chain CiO · · · HC‐type intraturn hydrogen bond. Noteworthy, the observed topology of the resulting 10‐membered hydrogen‐bonded ring is essentially similar to the one perceived for a classical β‐turn and the Asx‐turns, stabilized by a conventional intraturn hydrogen bond. Considering the signs as well as magnitudes of the backbone torsion angles and the orientation of the central peptide bond, the overall mimicked topology resembles the type II β‐turn or type II Asx‐turns. An analysis of Xaa–Thr sequences in high‐resolution X‐ray elucidated protein structures revealed the novel topology prevalence in functional proteins (unpublished). In view of indubitable structural as well as functional importance of nonconventional interactions in bioorganic and biomacromolecules, we intend to highlight the participation of Thr CγH in the creation of a short‐range CO · · · HCγ‐type interaction in peptides and proteins. © 2006 Wiley Periodicals, Inc. Biopolymers 81: 440–449, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Aminoglycoside–Quinacridine Conjugates: Towards Recognition of the P6.1 Element of Telomerase RNA
Authors: Kaiser Markus , Sainlos Matthieu , Lehn Jean‐Marie , Bombard Sophie , Teulade‐Fichou Marie‐Paule
Published: January 2006

A modular synthesis has been developed which allows easy and rapid attachment of one or two aminoglycoside units to a quinacridine intercalator, thereby leading to monomeric and dimeric conjugates. Melting temperature (Tm) experiments show that the tobramycin dimeric conjugate TD1 exhibits strong binding to the P6.1 element of human telomerase RNA. By contrast, tobramycin alone is much less efficient and the monomeric compound TM1 elicits a poor binding ability. Monitoring of the interaction by an electrophoretic mobility shift assay shows a 1:1 stoichiometry for the binding of the dimeric compound to the hairpin structure and confirms the lower affinity for a control duplex. Protection experiments with RNase T1 indicate interaction of the drug both in the stem and in the loop of the hairpin. Taken together, the data suggest a binding of TD1 inside the hairpin at the stem‐loop junction. The same trends are observed with paromomycin and kanamycin analogues but with a lower affinity.
Mechanism of Nitrate Reduction by Desulfovibrio desulfuricans Nitrate Reductase—A Theoretical Investigation
Authors: Leopoldini Monica , Russo Nino , Toscano Marirosa , Dulak Marcin , Wesolowski Tomasz Adam
Published: January 2006

The oxidative half‐reaction of oxygen atom transfer from nitrate to an MoIV complex has been investigated at various levels of theory. Two models have been used to simulate the enzyme active site. In the second, more advanced model, additional amino acid residues capable of significantly affecting the catalytic efficiency of the enzyme were included. B3LYP/6–31+G*, ONIOM, and orbital‐free embedding approaches have been used to construct the potential energy profile and to qualitatively compare the results of a QM/MM study with those obtained by a full quantum mechanical strategy. The study has confirmed the utility of the orbital‐free embedding method in the description of enzymatic processes.