bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation and Growth of Smectites In Bentonites: A Case Study From Kimolos Island, Aegean, Greece
Authors: Christidis George E. 
Published: June 2006

AbstractThe low-temperature alteration of a rhyolitic rock from Kimolos Island, Aegean, Greece, yielded an alteration profile characterized by gradual transition from fresh glass to bentonite containing homogeneous Chambers-type montmorillonite and then to a mordenite-bearing bentonite. Both mordenite and smectite were formed from poorly crystalline precursors, which probably had compositions comparable to that of the crystalline end-product. However, their composition may have been modified to some degree after reaction with the fluid phase. Particle length and width measurements of smectite crystals yielded lognormal profiles, which suggest supply-controlled crystal growth in an open system or random ripening in a closed system. The former mechanism is in accordance with the observed sustained supply of Mg and Fe by the fluid phase throughout the alteration profile and is believed to be the dominant formation mechanism of smectites in bentonites in general. In the mordenite-bearing zone, random ripening is expected in domains with low permeability, in which the system was essentially closed, favoring the formation of mordenite. The level of supersaturation with respect to smectite was probably lower in the mordenite-bearing zone. Smectite probably affected pore-fluid chemistry either through ion exchange or via dissolution of initially formed K-bearing smectite. The latter process raised the K+/(Na+ + Ca2+) activity ratio of the pore-fluid favoring K-bearing mordenite.
Methylene Blue Interactions with Reduced-Charge Smectites
Authors: Bujdák Juraj , Janek Marián , Madejová Jana , Komadel Peter 
Published: June 2006

AbstractThe objective of this work was to prepare series of reduced-charge materials from different parent Li-saturated dioctahedral smectites, to investigate the effects of temperature, chemical composition and charge location in smectites on the charge reduction and to characterize reduced-charge smectites (RCSs) using methylene blue (MB) adsorption. The layer charge decrease, induced by Li fixation, is correlated with the trends in the spectra of MB-RCS dispersions in the visible region (VIS) spectra. Distribution of the negative surface charge of the clay minerals controls the distance between the adsorbed MB cations and thus affects the formation of MB dimers and higher agglomerates. Because each form of MB (monomer, dimer, higher agglomerate, J-aggregates) absorbs light at a different wavelength, the VIS spectra of MB depend sensitively on the charge density at the clay surface. Both cation exchange capacity (CEC) values and spectra of MB-clay dispersions clearly detect extensive reduction of the layer-charge density in reduced-charge montmorillonites (RCMs) upon Li-thermal treatment. The extent of charge reduction depends on the temperature of the thermal treatment, as well as on the octahedral charge of the montmorillonite. Reduction of the layer charge proceeds to a much lesser extent for smectites with mainly tetrahedral charge and high Fe content (Fe-rich beidellite and ferruginous smectite). Both CEC data and MB spectra detect only a slight decrease of the layer charge density, which relates to the low octahedral charge of these minerals. Following heating at higher temperatures (120-160°C), slightly higher Li fixation is indicated by CEC values; however, no charge reduction is confirmed by MB spectra. Release of protons accompanying Li+ fixation in Fe-rich smectites heated at 180 or 200°C was detected in the spectra of MB-clay dispersions and confirmed by potentiometric titrations.
Influence of Ionic Environment and pH on the Electrokinetic Properties of Ball Clays
Authors: Galassi Carmen , Costa Anna Luisa , Pozzi Paolo 
Published: June 2006

AbstractThree ball clays (SP from England, TSMA from France and UK from the Ukraine) were characterized for their dry and wet colloidal properties. On the basis of X-ray diffraction and chemical analyses the clays were classified as kaolinite-rich clay, smectitic kaolinite-rich clay and illitic kaolinite-rich clay. The ζ (zeta) potential at the clay-water interface as a function of pH, in three different electrolytes, was investigated using an electroacoustic technique. Starting from measurements of dynamic mobility, the calculated ζ potential was found to be almost constant as a function of pH for the TSMA and UK clays, while it increased from −20 to −60 for the SP clay, when potassium nitrate was used as an electrolyte. The behavior of the three clays in calcium and magnesium nitrate was slightly different: SP showed a smaller increase in ζ potential, while a small deviation from the constant behavior of the UK clay was found. The results are explained in terms of the surrounding-ion atmosphere in light of the chemical-physical properties measured. Our results may well be of use to those involved in ceramic processing.
Effect of KCl and CaCl2 as Background Electrolytes on the Competitive Adsorption of Glyphosate and Phosphate on Goethite
Authors: Gimsing Anne Louise , Borggaard Ole K. 
Published: June 2006

AbstractCompetitive adsorption between glyphosate and phosphate on goethite was evaluated. The influence of background electrolyte on the adsorption of glyphosate and phosphate was also investigated by using 0.01 M KCl, 0.1 M KCl and 0.01 M CaCl2 as background electrolytes. Experiments showed that phosphate displaced adsorbed glyphosate from goethite, whereas glyphosate did not displace phosphate. Results also showed that the background electrolyte had a strong effect on phosphate adsorption, but little effect on glyphosate adsorption. Thus, there are differences between the adsorption of glyphosate and phosphate. The study also showed that 0.01 M KCl caused dispersion of goethite, resulting in inefficient filtering, and that phosphate precipitated as calcium phosphates in 0.01 M CaCl2 background electrolyte solutions. The results suggest that 0.1 M KCl is a more suitable background electrolyte to determine competitive adsorption processes involving glyphosate and phosphate.
Thickness and Surface Characteristics of Colloidal 2:1 Aluminosilicates Using an Indirect Fourier Transform of Small-Angle X-Ray Scattering Data
Authors: Shang Chao , Rice James A. , Lin Jar-Shyong 
Published: June 2006

AbstractAn indirect Fourier transformation applied to small-angle X-ray scattering data has been used to determine the thickness and surface properties of two common clay minerals. For an illite system, the particle density distribution function (PDDF) generated by the analysis gave a correct description of particle geometry, and the calculated electron density profile was in accordance with the theoretical electron density distribution for this mineral. This approach provides the opportunity to determine the thickness of fundamental particles of illite while avoiding the difficulties encountered in other methods. Both the PDDF and the electron density profile accurately predict the thickness of Na-montmorillonite layers, and the results suggest that an electron inhomogeneity exists at the interface of this mineral.
Rheology of Na-Rich Montmorillonite Suspension as Affected by Electrolyte Concentration and Shear Rate
Authors: Heller Hadar , Keren Rami 
Published: June 2006

AbstractRheological measurements were used to evaluate the particle-particle associations of Na-rich montmorillonite in suspensions, under various electrolyte concentrations. A 2% free electrolyte clay suspension showed pseudoplastic flow behavior and had a high apparent viscosity, attributed at low shear rates to the high volume fraction of the suspended clay platelets, the flexibility of the platelets, and the presence of edge-to-edge association. The breaking of edge-to-edge associations and the progressive orientation of the individual platelets in the direction of flow contribute to the reduction in viscosity with increasing shear rate.The compression of the diffuse double layer at a NaCl concentration of 10 mEq L-1 contributes to the free movement of the individual platelets, even at low shear rates. The flow behavior changed from pseudoplastic to plastic at an NaCl concentration of 100 mEq L-1. At this electrolyte concentration, face-to-face associations of specific junction points at certain areas of the planar surface are probably occurring.The apparent viscosity of the clay suspension for the two particle-size ranges (<2 and <0.02 μm) at all shear rates converged to a minimum value of 4.5 mPa s at NaCl concentrations of 10–20 mEq L-1. On both sides of the minimum, the lower the shear rate, the greater the slope. The apparent viscosity of a 2% suspension of Na-rich montmorillonite <0.02 μm particles, however, was significantly greater than that observed for a suspension of <2 u,m particles. This high apparent viscosity is attributed to the increase in edge surface area and the number of clay particles in a unit volume.We suggest that edge-to-edge association between Na-rich montmorillonite platelets prevails when the NaCl concentration is below the electrolyte critical concentration, for which the apparent viscosity of the suspension is at its minimum value, whereas face-to-face association prevails at NaCl concentrations above this critical value.
Possible Role of Microbial Polysaccharides in Nontronite Formation
Authors: Ueshima Masato , Tazaki Kazue 
Published: June 2006

AbstractNontronite and microbes were detected in the surface layers of deep-sea sediments from Iheya Basin, Okinawa Trough, Japan. Nontronite, an Fe-rich smectite mineral, was embedded in acidic polysaccharides that were exuded by microbial cells and electron microscopy showed that the nontronite layers were apparently oriented in the polysaccharide materials. We propose that the formation of nontronite was induced by the accumulation of Si and Fe ions from the ambient seawater and that extracellular polymeric substances (EPS) served as a template for layer-silicate synthesis. Experimental evidence for this hypothesis was obtained by mixing a solution of polysaccharides (dextrin and pectin) with ferrosiliceous groundwater. After stirring the mixture in a sealed vessel for two days, and centrifuging, Fe-rich layer silicates were identified within the precipitate of both the dextrin and pectin aggregates, whereas rod-shaped or spheroidal Si-bearing iron hydroxides were found in the external solution. Microbial polysaccharides would appear to have affected layer-silicate formation.
Human kallikrein 10, a predictive marker for breast cancer
Authors: Zhang Ying , Bhat Ishfaq , Zeng Musheng , Jayal Goyal , Wazer David E. , Band Hamid , Band Vimla 
Published: June 2006

AbstractOur laboratory is involved in identifying genes that can be used as early diagnostic or prognostic markers in breast cancer. We previously identified a gene (NES1) that is expressed in normal but not in transformed mammary epithelial cells (MECs).NES1is located on chromosome 19q13.4 within the kallikrein locus and thus was designated as human kallikrein 10 (hK10), although we have been unable to detect any protease activity. Importantly,hK10expression is decreased in a majority of breast cancer cell lines. Transfection ofhK10intohK10-negative breast cancer cells reduces the tumorigenicity. Using methylation-specific PCR and subsequent sequencing, we demonstrate a strong correlation between hypermethylation ofhK10and loss of mRNA expression. Further analysis showed that essentially 100% of normal breast specimens hadhK10expression, whereas 46% of ductal carcinomain situ(DCIS) and the majority of infiltrating ductal carcinoma (IDC) samples lacked thehK10 mRNA. Importantly,hK10-negative DCIS diagnosed at the time of biopsy were subsequently diagnosed as IDC at the time of definitive surgery. It has been shown that hK10 protein expression is regulated by steroids. In addition to breast cancers, hK10 is downregulated in cervical cancer, prostate cancer and acute lymphocytic leukemia, whereas it is upregulated in ovarian cancers. These results point to the paradoxical role of hK10 in human cancers and underscore the importance of further studies of this kallikrein.
Improved prostate cancer detection with a human kallikrein 11 and percentage free PSA-based artificial neural network
Authors: Stephan Carsten , Meyer Hellmuth-Alexander , Cammann Henning , Nakamura Terukazu , Diamandis Eleftherios P. , Jung Klaus 
Published: June 2006

AbstractHuman kallikrein 11 (hK11) was evaluated in a percentage free PSA-based artificial neural network (ANN) to reduce unnecessary prostate biopsies. Serum samples from 357 patients with (n=132) and without (n=225) prostate cancer (PCa) were analyzed and ANN models were constructed and compared to all parameters. The discriminatory power of hK11 was lower than that of PSA, but receiver operator characteristic (ROC) analyses demonstrated significantly larger areas under the curves for the ANN compared to all other parameters. ANNs with hK11 may lead to a further reduction in unnecessary prostate biopsies, especially when analyzing patients with less than 15% free PSA.
A Robust Structural Stress Parameter for Evaluation of Multiaxial Fatigue of Weldments
Authors: Dong P , Hong JK 
Published: June 2006

Abstract
In this paper, the applicability of a new mesh-insensitive structural stress method is examined for the evaluation of multiaxial fatigue behaviors in welded joints. The mesh-insensitive structural stress method proves to be effective in characterizing stress concentration effects in multi-axial fatigue of welded components. In seeking an effective structural stress based fatigue parameter, some well-known published test data were analyzed. These include those published by researchers, e.g., from the Electric Power Research Intitute (EPRI), the Fraunhofer-Institute for Structural Durability (LBF), the University of Illinois at Urbana-Champaign (UIUC), and the Welding Institute (TWI) under bending, torsion, and in-phase and out-of-phase loading combinations. An effective structural stress parameter has then been formulated in a form of a proposed modified Gough's ellipse for considering both in-phase and out-of-phase multiaxial loading conditions. The aforementioned multiaxial fatigue data from a total of five independent sources can be effectively correlated with a structural stress based parameter presented in this paper, without introducing any other material-related empirical parameters. The present method is rather simple to use for day-to-day finite element based fatigue evaluation of welded joints in actual structures subjected to multiaxial loading conditions.
Feasibility Study on a Simple Method of Retrospective Neutron Dosimetry for Reactor Internals and Reactor Vessel
Authors: Hayashi K , Tayama R , Watanabe Y , Nakamura T , Kubota I , Hayashi H , Yamasaki T , Yuya H 
Published: June 2006

Abstract
Nondestructive and simple retrospective dosimetry method was developed. Mercuric iodide or cadmium zinc telluride detector was used as a detector to measure 54Mn, 58Co, and 60Co that were created in reactor internals and vessels. Detector is surrounded by tungsten collimator which shield background gamma rays and detect gamma rays from desired measuring point. Photopeak count rate of this detector were calculated using the mcnp-4c code. This response was calculated for each reactor internal geometry that was irradiated by unit neutron flux which energy spectrum was calculated by the tort code. Neutron fluence is calculated using precalculated response, measuring time, decay time and reactor power history. We can also get Displacement per Atom (DPA), hydrogen and helium production simultaneously using neutron spectrum precalculated in reactor vessel. Because the time and cost of this method are much less than the sampling method, we can measure at many positions and even get a contour map.
IT Projects Performance Indices and Evaluation
Authors: Akinyokun OC , Chiemeke SC 
Published: June 2006

Abstract
Information Technology (IT) is the fastest growing technology in the world today. Investment on IT projects in all the sectors of the world economy has been on the increase in the past ten years. This paper proposes 50 performance indices of IT projects and a tool for evaluating them. Some popular IT projects in Nigeria were surveyed by administering questionnaires and holding meetings with their principal actors. The performance indices were subjected to factor analysis by principal components using Statistical Package for Social Scientists (SPSS). Eleven factors were extracted and the percentage contribution of each factor to the success of IT projects was estimated. The total sum of the percentage contributions of all the factors was found to be less than 100. This revealed that there were some extraneous factors whose related performance indices were not considered in the administered questionnaire which were liable to play a significant role in the success of IT projects. Moreover, a factor scores coefficient matrix that can be used to estimate and rank the assessment of each Assessor of IT projects was generated.
Mechanism of G‐protein Activation by Rhodopsin†
Authors: Shichida Yoshinori , Morizumi Takefumi 
Published: June 2006

AbstractRhodopsin is a member of the family of G‐protein‐coupled receptors (GPCRs), and is an excellent molecular switch for converting light signals into electrical response of the rod photoreceptor cells. Light initiates cis–trans isomerization of the retinal chromophore of rhodopsin and leads to the formation of several thermolabile intermediates during the bleaching process. Recent investigations have identified spectrally distinguishable two intermediate states that can interact with the retinal G‐protein, transducin, and have elucidated the functional sharing of these intermediates. The initial contact with GDP‐bound G‐protein occurs in the meta‐Ib intermediate state, which has a protonated Schiff base as its chromophore. The meta‐Ib intermediate in the complex with the G‐protein converts to the meta‐II intermediate with releasing GDP from the α‐subunit of the G protein. Meta‐II has a de‐protonated Schiff base chromophore and induces binding of GTP to the α‐subunit of the G‐protein. Thus, the GDP–GTP exchange reaction, namely G‐protein activation, by rhodopsin proceeds through at least two steps, with conformational changes in both rhodopsin and the G‐protein.
IGF-Binding Protein-1 Levels Are Related to Insulin-Mediated Glucose Disposal and Are a Potential Serum Marker of Insulin Resistance
Authors: Maddux Betty A. , Chan Adelene , Mandarino Lawrence J. , Goldfine Ira D. , De Filippis Elena A. 
Published: June 2006

OBJECTIVE—IGF-binding protein (IGFBP)-1 is negatively regulated by insulin. We determined whether the measurement of IGFBP-1 in serum is a useful marker of insulin resistance.
RESEARCH DESIGN AND METHODS—Twenty-three subjects underwent a euglycemic insulin clamp. Glucose disposal rates (M) were then correlated with measurements of IGFBP-1, fasting insulin levels, homeostasis model assessment (HOMA), and BMI.
RESULTS—IGFBP-1 levels more strongly correlated with M (R = 0.73) than the other parameters such as BMI or HOMA. The level of this protein decreased in individuals who became more insulin sensitive by exercise training.
CONCLUSIONS—These studies show a strong correlation between insulin sensitivity and the serum levels of IGFBP-1. These studies suggest, therefore, that measurement of this protein may be valuable in identifying those individuals with insulin resistance and those individuals who respond to interventional strategies.
Short Stature and the Risk of Adiposity, Insulin Resistance, and Type 2 Diabetes in Middle Age
Authors: Asao Keiko , Kao W.H. Linda , Baptiste-Roberts Kesha , Bandeen-Roche Karen , Erlinger Thomas P. , Brancati Frederick L. 
Published: June 2006

OBJECTIVE—To investigate the association between stature-related measurements (height, leg length, and leg length–to–height ratio) and adiposity, insulin resistance, and glucose intolerance.
RESEARCH DESIGN AND METHODS—We conducted a cross-sectional analysis of a nationally representative sample of 7,424 adults aged 40–74 years, from the Third National Health and Nutrition Examination Survey (1988–1994). The main outcome measures were percent body fat, homeostasis model assessment of insulin resistance (HOMA-IR), and glucose intolerance based on the World Health Organization’s 1985 criteria for an oral glucose tolerance test.
RESULTS—Shorter height and leg length, and lower leg length–to–height ratio, were associated with higher percent body fat, especially in women. Lower leg length–to–height ratio was associated with greater insulin resistance estimated by HOMA-IR. In multinomial regression models adjusting for potential confounders, including percent body fat, the relative prevalence of type 2 diabetes per 1-SD lower values in height, leg length, and leg length–to–height ratio were 1.10 (95% CI 0.94–0.29), 1.17 (0.98–1.39), and 1.19 (1.02–1.39), respectively.
CONCLUSIONS—Our study supports the hypothesis that adult markers of prepubertal growth, especially leg length–to–height ratio, are associated with adiposity, insulin resistance, and type 2 diabetes in the general U.S. population.
Assessing the Impact of Visual Acuity on Quality of Life in Individuals With Type 2 Diabetes Using the Short Form-36
Authors: Clarke Philip M. , Simon Judit , Cull Carole A. , Holman Rury R. 
Published: June 2006

OBJECTIVE—We sought to ascertain quality-of-life measures and utility values associated with visual acuity in type 2 diabetes.
RESEARCH DESIGN AND METHODS—The Medical Outcome Study Short Form with 36 items (SF-36) was administered to 4,051 individuals with type 2 diabetes who were enrolled in the Lipids in Diabetes Study, and their best attainable vision was determined using an Early Treatment of Diabetic Retinopathy Study chart, expressed as a LogMAR score. Eight domain scores and a utility value representing an overall quality-of-life score were calculated using predefined algorithms. The associations between quality of life measured and best-eye visual acuity were assessed graphically and by regression analysis.
RESULTS—All eight SF-36 domain scores were negatively associated with reduced visual acuity. The impact of lower levels of visual acuity ranged from a decline of 1.3 units for a 0.1-LogMAR increase for physical functioning and 0.6 units in mental health. Regression analysis indicated a negative association (P &lt; 0.001) between utility and reduced visual acuity after controlling for sex, BMI, smoking status, and history of diabetes complications. Patients whose LogMAR scores equated to legally blind had, on average, 0.054 (95% CI 0.034–0.074) lower utility compared with patients with normal visual acuity.
CONCLUSIONS—Reduced visual acuity is negatively associated with quality of life. The utility scores estimated here should inform studies quantifying the burden of diabetes and those evaluating potential therapies for treating or preventing diabetic eye diseases.