bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Resolution Transmission Electron Microscopy Study of Newly Formed Sediments in the Atlantis II Deep, Red Sea
Authors: Taitel-Goldman Nurit , Singer Arieh
Published: June 2006

Iron and silicon in various proportions are the major components of the newly formed hydrothermal sediments in the Atlantis II Deep, Red Sea. Iron-rich 2:1 phyllosilicates with morphologies varying from ribbons to plates represent clays in initial formation stage. Well-crystallized goethite particles contain domains of hundreds of nanometers in length with the rare presence of dislocations. Molar compositions show ratios of Si/Fe = 0.12 and Al/Fe = 0.05. Euhedral feroxyhyte with curled edges forms clusters with the goethite. The feroxyhyte has ratios of Si/Fe = 0.3 and are the major Si-associated iron oxides. Two nanometer-size phases showing short range periodity are common in the newly formed Atlantis II sediments: (1) hematite with traces of Si and (2) ferrihydrite with Si/Fe molar ratios varying between 0.17–0.89. The ferrihydrite forms large clusters. Hematite appears also as well-crystallized large crystals. Feroxyhyte probably forms at the transition zone between Red Sea Deep Water and the upper convective layer in the brine, whereas goethite and ferrihydrite form in the upper convective layer. The two forms of hematite represent two stages of recrystallization, which occur within the brine.
Mica Structure and Fibrous Growth of Illite
Authors: Güven Necip
Published: June 2006

The relative growth rates of the three joint chains of silica tetrahedra and metal octahedra in the [100], [1̅10] and [1̅1̅0] directions within the mica layer (referring to the 1M unit-cell) seem to control the morphology of mica crystallites. Laths and fibers are the products of relatively fast growth along the [100] direction compared to growth along the [1̅10] and [1̅1̅0] directions. The (010) growth front in 1M micas with trans-octahedral vacancies exposes a pair of reactive OH ions that can form organic or inorganic complexes and ‘poison’ the growth on the (010) face.

Authigenic illite fibers in two sandstones with contrasting lithologies are found to have grown on mica or kaolinite cores. Illite fibers appear in single sets or in multiple sets, 120° apart. This texture seems to be related to the stacking sequence of the layers in mica or kaolinite in the core of these fibers.
Unusual X-Ray Characteristics of Vermiculite from Wiry, Lower Silesia, Poland
Authors: Sakharov Boris A. , Dubińska Elżbieta , Bylina Paweł , Kaproń Grzegorz
Published: June 2006

Coarse-grained vermiculite from a serpentinite-pegmatite thermal zone displays a rational series of narrow 14.4 Å basal reflections and an unusual broad 28 Å peak. X-ray diffraction simulations and fitting techniques show that the 28 Å peak is related to 28 Å domains consisting of elongated 2:1 layers of different lengths. The domains are located at the crystal edges of the vermiculite.
Nordstrandite in Bauxite Derived from Phonolite, Lages, Santa Catarina, Brazil
Authors: Dani Norberto , Formoso Milton Luiz Laquintinie , Decarreau Alain , Meunier Alain
Published: June 2006

Nordstrandite from Lages represents the first occurrence of this mineral in an oxisoil that does not involve the influence of a calcareous substrate. This is also the first reported occurrence in Brazil. Nordstrandite occurs near the city of Lages only in the weathered bedrock facies, mostly where the circulation of meteoric water is restricted. There is also a close association between nordstrandite and the weathering of modified pseudoleucite structures. The interaction of meteoric water and feldspathic alkaline country rock with uncommon texture and mineralogy (rich in nepheline, sodalite, nosean, analcime and natrolite) promotes the development of solutions enriched in alkaline ions with basic pH, necessary to form nordstrandite. A detailed study by X-ray diffraction (XRD) and infrared (IR) spectroscopy in natural or chemically leached samples was performed to identify the Al(OH)3 polymorphs of gibbsite and nordstrandite.
Clay Poultices in Salt Extraction from Ornamental Stones: A Statistical Approach
Authors: Vicente Maria Angeles , Vicente-Tavera Santiago
Published: June 2006

The extraction of salts by layered (bentonite) and fibrous (sepiolite) clay poultices from stone materials currently used in Heritage buildings was studied. Analyses were performed on stones affected by salts but not submitted to humidity, and also on stones affected by salts and simultaneously submitted to continuous or intermittent humidity during the salt-extraction process. From the experimental results and the statistical analysis, the application of two successive poultices is sufficient for an efficient extraction of Cl− and NO3- in the absence of humidity. However, under humid conditions, the efficiency of the method is reduced considerably. For SO42-, the use of hydrotalcites (anionic clays) is recommended for more effective extraction.
The Relationship between the Thermal Behavior of Clinoptilolite and Its Chemical Composition
Authors: Kitsopoulos Konstantinos P.
Published: June 2006

The matrix of the Pliocene volcaniclastics from the Akrotiri area of the Santorini island (Greece) is dominated by clinoptilolite. Smectite, occasionally illite-smectite, opal-CT, cristobalite and mordenite are also present. The clinoptilolite-rich samples were heated at 460 and 560°C for 12 h and the reductions in the intensity of the 020 diffraction peak were measured. Electron microprobe analysis (EMPA) was then used to study the chemical composition of the clinoptilolite. Statistical analysis proved a strong and quantifiable relationship between the reduction of the 020 diffraction peak of the clinoptilolite and the Na/K ratio. A representative set of microprobe analyses of clinoptilolite was performed before any correlation with thermal behavior was attempted. The presence of K in the structure of clinoptilolite as well as its relationship with Na are most important in the thermal behavior of clinoptilolite.
Simulations of Interlayer Methanol in Ca- and Na-Saturated Montmorillonites Using Molecular Dynamics
Authors: Pintore Marco , Deiana Salvatore , Demontis Pierfranco , Manunza Bruno , Suffritti Giuseppe Baldovino , Gessa Carlo
Published: June 2006

Molecular dynamics computer simulations were used to study methanol molecules confined between the layers of 2:1 phyllosilicates. The model systems are based on natural Ca- and Na-rich montmorillonites. Data from the literature and determined by fitting the calculated layer spacing to experimental values were employed to obtain interactions between the charged 2:1 layers and the solvent molecules. The montmorillonite surface atoms were held rigid and the methyl group in the methanol molecule was represented by a soft Lennard-Jones sphere. Electrostatic interactions were determined by the Ewald sum method, whereas the van der Waals interactions were described by a Lennard-Jones potential. Comparison of our results with diffraction data indicates a good reproduction of the layer spacing. After the initial solvent layer forms, additional solvent layers form only after previous layers are complete. Each Ca2+ and Na+ ion in the monolayer has four and two methanol molecules, respectively, in the first solvation shell, whereas the solvation shell in the multilayer contains six and four methanol molecules, respectively. This agrees well with experimental data.
Atomic Force Microscopy Study of Hydrothermal Illite in Izumiyama Pottery Stone from Arita, Saga Prefecture, Japan
Authors: Kuwahara Yoshihiro , Uehara Seiichiro , Aoki Yoshikazu
Published: June 2006

The surface microtopographic observations and analyses of Izumiyama hydrothermal illite particles were made by utilizing tapping-mode atomic force microscopy (TMAFM). The Izumiyama illite particles showed platy to lath shapes. Platy particles exhibited various spiral growth patterns, i.e. circular, malformed circular, or polygonal single unit-cell layer spirals, polygonal parallel step spiral, or interlaced spiral patterns. The polygonal parallel step spiral and interlaced spiral patterns are formed by two single unit-cell layers rotated by 180° and 120° arising from a single screw dislocation point, respectively. The spiral patterns indicate that the illite particles have 1M, 2O and 2M1 polytypes. Lath-shaped particles show only interlacing patterns supporting the formation of 2M1 structures.

Particles showing circular or malformed circular spirals were found to be thinner and to have narrower step separations than particles showing polygonal spirals. Polygonal platy and lath-shaped particles showing interlaced patterns tended to be thicker and to have wider step separations than the other polygonal platy particles.

These results suggest that the Izumiyama illites crystallize as the result of a mechanism involving solution-mediated polytypes and spiral-type transformations of illite. The mechanism involves the Ostwald ripening process, i.e. a transformation of the polytype and spiral shape. The sequence of crystallization of the Izumiyama illite is: 1M circular spirals → 1M, 2O polygonal spirals → 2M1 polygonal spirals occurring during crystal growth and sequentially overgrowing on the initial particle surfaces. The super-saturation of the hydrothermal solution probably decreases gradually during the transformation, and this decrease may cause not only the transformation from a circular to a polygonal crystal morphology but also the development of a lath habit due to the inhibition of the growth rate in the [010] direction of the particle.
A HRTEM Study of Cronstedtite: Determination of Polytypes and Layer Polarity in Trioctahedral 1:1 Phyllosilicates
Authors: Kogure Toshihiro , Hybler Jiří , Ďurovič Slavomil
Published: June 2006

It is shown that polytypes or stacking sequences of cronstedtite, an Fe-bearing trioctahedral 1:1 phyllosilicate, can be determined using near-atomic high-resolution transmission electron microscopy (HRTEM). By viewing along the [010], [310] and directions (orthohexagonal indexing), the four groups of the standard polytypes can be distinguished. Imaging along the [100], [110] and directions allows determination of the polytypes in each group. The polytypic sequences of groups A and C are intergrown at the monolayer level in cronstedtite from Lostwithiel, England, which is a new insight if compared with previous suggestions that layer stackings characteristic of different groups do not occur together. The HRTEM images also revealed the relationship between the layer polarity and the morphology of the cronstedtite crystals, where the tetrahedral sheet side points towards the top of the truncated pyramidal shape of the crystal.
Comparison of Evolution of Trioctahedral Chlorite/Berthierine/Smectite in Coeval Metabasites and Metapelites from Diagenetic to Epizonal Grades
Authors: Mata M. P. , Giorgetti G. , Árkai P. , Peacor D. R.
Published: June 2006

The evolution of texture, structure and chemical composition of chloritic clays in coeval pairs of metabasites and metapelites of a prograde sequence from the Bükk Mountains has been investigated using electron microscopy techniques. Samples are from the Bükkium (innermost Western Carpathians, Hungary) that underwent Alpine metamorphism, ranging from late diagenesis to epizone for pelites and from prehnite-pumpellyite to greenschist facies for the metabasites.

Although bulk-rock compositions, textures and primary minerals are different, chlorite evolved at similar rates in coeval metabasites and metasediments, but along different paths. The principal similarities in the prograde sequence are a decrease in the percentage of interstratified material in both dioctahedral and trioctahedral phyllosilicates and increase in thicknesses of chlorite and illite crystallites. The principal difference is in the type of interstratification in chlorite, with berthierine in metapelites, and smectite (saponite) in metabasites, although smectitic mixed layers also occur in the former. The evolution of trioctahedral phyllosilicates is marked by a decrease in the number of mineral species with increasing grade, chlorite, sensu stricto, being the only trioctahedral mineral at higher grades. This is consistent with the trend in reaction progress where both metastable systems (metabasites and metapelites) tend toward the same end-member, thermodynamically stable chlorite, as well as texture (crystal size), and where all intermediate states are metastable, and determined by the Ostwald step rule.
Diagenesis of Dioctahedral and Trioctahedral Smectites from Alternating Beds in Miocene to Pleistocene Rocks of the Niigata Basin, Japan
Authors: Son Byeong-Kook , Yoshimura Takahisa , Fukasawa Hikaru
Published: June 2006

Clay mineral diagenesis in the Niigata basin is documented by mineralogical and chemical analysis of clay minerals from cuttings from the Shinkumoide SK-1D (SSK-1D) well which is characterized by alternating beds containing dioctahedral and trioctahedral smectite minerals with increasing depth. Dioctahedral smectite shows a progressive increase in illite interstratification with increasing depth. The transition of dioctahedral smectite to interstratified illite-smectite (I-S) is supported chemically by an increase in K and Al and a decrease in Si with increasing depth. In contrast, trioctahedral smectite (saponite) reacts to form a 1:1 interstratified chlorite-smectite (C-S) with increasing burial depth and temperature. Considering the geology and the occurrence of smectite, the SSK-1D smectites probably altered diagenetically from two different parent materials: dioctahedral smectite is derived from clastic sediments and transforms to interstratified illite-smectite, whereas trioctahedral smectite is derived from andesitic pyroclastic rocks and transforms to interstratified chlorite-smectite.

The C-S occurs at the same depth of ~3200 m as the conversion of randomly interstratified (R = 0) I-S to (R = 1) I-S. Furthermore, the depth is compatible with a Tmax temperature of 430-435°C, which indicates the starting temperature for oil generation from organic matter. The temperature of the conversion of (R = 0) I-S to (R = 1) I-S and the start of corrensite formation is estimated at 110-120°C based on the time-temperature model suggested by others. The clay-mineral diagenesis in the SSK-1D further suggests that I-S and C-S can act as geothermometers in clastic and pyroclastic sediments provided that the effect of time is considered.
Hydroxyl-Stretching Bands in Curve-Fitted Micro-Raman, Photoacoustic and Transmission Infrared Spectra of Dickite from St. Claire, Pennsylvania
Authors: Shoval S. , Yariv S. , Michaelian K. H. , Boudeulle M. , Panczer G.
Published: June 2006

The OH-stretching region in curve-fitted micro-Raman, photoacoustic and transmission IR spectra of St. Claire dickite was investigated. Polarized Raman spectra recorded from th. (001) an. (010) faces of the dickite crystal displayed six prominent OH bands. The relative intensities depend strongly on both the orientation of the crystallographic axes and the direction of the electric vector of the laser beam. Four out-of-plane vibrations, AA, Az, CA and Cz, at ~3710, 3706, 3654 and 3643 cm-1 respectively, predominate when the electric vector is perpendicular to the dickite plates. Two in-plane vibrations, Dz and DA at 3627 and 3623 cm-1, intensify when the electric vector is parallel to the plane. The relationship between band intensity and crystal orientation was interpreted in terms of longitudinal optic (LO) and transverse optic (TO) crystal vibration modes. These LO and TO crystal modes were also observed in curve-fitted photoacoustic and transmission IR spectra of coarse, non-oriented crystals of the dickite.
Mineralogy, Geochemistry and Utilization Study of the Madayi Kaolin Deposit, North Kerala, India
Authors: Manju C. S. , Narayanan Nair V. , Lalithambika M.
Published: June 2006

The Madayi clay deposit consists of a thick sequence of residual white kaolinitic clay underlying the sedimentary Warkallai Formation, which includes gray carbonaceous kaolinitic clays, lignite, ferruginous kaolinitic clays, laterite and bauxite with ferricretes. The conditions of clay genesis and the economic significance of the major residual kaolin seam have been investigated. The raw clay and <2 μm fractions were subjected to X-ray diffraction (XRD), chemical analysis, differential thermal analysis (DTA), Fourier transform infrared (FTIR) spectroscopic and scanning electron microscopic (SEM) studies. The firing behavior of the <45 μm fraction of the major residual clay sequence (L), was investigated systematically to determine the potential industrial use of this kaolin.

Geochemical and morphological studies of different strata indicate the following conditions for clay formation. (1) intense lateritized weathering conditions for kaolinization of the residual white clay from parent quartzo-felspathic mica-gneiss. (2) reducing environment for the gray carbonaceous layers; an. (3) oxidizing environment for the uppermost hematite-rich ferruginous clay. Pyrite/marcasite enriched detrital gray carbonaceous clay shows two distinct environments forin situkaolinite crystallization. (1) within plant fossils influenced by the high organic content and FeS2leaching; and (2) precipitation from solution.

Incomplete kaolinization of white residual clay is evident from the presence of pyrophyllite, muscovite with lenticular cleavage void and a lower percentage of fines (<2 μm). The plant fossils from the uppermost portion of residual clay show pyrite mineralization. The Hinckley Index, FTIR and rare earth analysis point towards diverse geochemical environments of deposition and technological evaluation indicates its suitability for application in the ceramics industry.
Baseline Studies of the Clay Minerals Society Source Clays: Geological Origin
Authors: Moll William F.
Published: June 2006

In any clay deposit, the nature of the mineral assemblage and the composition of individual clay minerals can change radically in a few em. Consequently, any given locality can contain many subtly different types of clay minerals. Results from different laboratories on ostensibly the same clay material may not always be comparable because the samples may indeed not contain an assembly of identical clay minerals. Such confusion slows the understanding of this important group of minerals. Several attempts were made to provide investigators with reasonably constant clay materials, the first being that of the American Petroleum Institute Project 49 (Kerr, 1949). The Clay Minerals Society Source Clays project proposed to provide investigators with gently homogenized clay materials, carefully collected and processed under the supervision of clay specialists. The collection would include metric ton amounts to ensure a long-lasting collection. The program began in 1972, with the introduction of the materials described in this paper. Later the program expanded to include the Special Clays. These samples are materials not amenable to homogenization, or they are available in very small amounts.
Baseline Studies of the Clay Minerals Society Source Clays: Chemical Analyses of Major Elements
Authors: Mermut Ahmet R. , Cano Angel Faz
Published: June 2006

Chemical analysis is an essential step to establish the nature of minerals (Newman, 1987). The techniques used in rock and mineral analyses are generally valid for the analyses of clays. Additional information from other analytical techniques, which are mentioned here, is needed for accurate interpretation of the chemical analysis results of major elements (Gabis, 1979). In traditional chemical analyses, the aim is to obtain accurate analyses for all elements present in the sample, in such a way that the sum of elements expressed as oxides, including hydration and structural water, approaches the sample weight as closely as possible.
Baseline Studies of the Clay Minerals Society Source Clays: Layer-Charge Determination and Characteristics of Those Minerals Containing 2:1 Layers
Authors: Mermut Ahmet R. , Lagaly G.
Published: June 2006

The layer charge is perhaps the single most significant characteristic of 2: 1 layer phyllosilicates. Layer charge affects cation-retention capacity and adsorption of water, and various polar organic molecules. The effects of layer charge on the sorptive properties of organo- clays were illustrated by Lee et al. (1990). It is generally agreed that the classification of 2: 1 silicate clays, which is a continuing problem, may be resolved by taking into account the magnitude of the layer charge (Bailey et al., 1971; Malla and Douglas, 1987). Studies on structural chemistry also confirm the importance of the layer charge for the characterization of the 2:1 phyllosilicates (Newman and Brown, 1987).
Baseline Studies of the Clay Minerals Society Source Clays: Powder X-Ray Diffraction Analyses
Authors: Chipera Steve J. , Bish David L.
Published: June 2006

The Clay Minerals Society maintains a repository of Source Clays to provide scientists and researchers with a readily available supply of consistent materials so that research conducted by different groups can be correlated to identical material. These Source Clays include kaolinite, smectite, chlorite, vermiculite, illite, palygorskite and other minerals. As most of the Source Clays are naturally occurring materials, they typically contain minor to significant amounts of other mineral impurities. When conducting research using these samples, it is important that their mineral content be well characterized. It is also often desirable to remove these impurities to produce pure clay samples. For example, when studying the biological effects of a particular clay mineral, it is imperative that all contaminants (e.g. crystalline silica minerals) be removed from the clay in question so that experimental results can be attributed to the clay alone. If purification is required, the clays must be purified in a manner that does not significantly alter the physical or chemical properties of the samples. This chapter describes the X-ray diffraction (XRD) characteristics of a suite of Source Clays of The Clay Minerals Society and demonstrates methods of purification based on Stokes' law of settling in suspension that can be used to purify the clays.
Baseline Studies of the Clay Minerals Society Source Clays: Infrared Methods
Authors: Madejová Jana , Komadel Peter
Published: June 2006

Infrared (IR) spectroscopy has a long and successful history as an analytical technique and is used extensively (McKelvy et al., 1996; Stuart, 1996). It is mainly a complementary method to X-ray diffraction (XRD) and other methods used to investigate clays and clay minerals. It is an economical, rapid and common technique because a spectrum can be obtained in a few minutes and the instruments are sufficiently inexpensive as to be available in many laboratories. An IR spectrum can serve as a fingerprint for mineral identification, but it can also give unique information about the mineral structure, including the family of minerals to which the specimen belongs and the degree of regularity within the structure, the nature of isomorphic substituents, the distinction of molecular water from constitutional hydroxyl, and the presence of both crystalline and non-crystalline impurities (Farmel, 1979).
Baseline Studies of the Clay Minerals Society Source Clays: Thermal Analysis
Authors: Guggenheim Stephen , Koster van Groos A. F.
Published: June 2006

Thermal analysis involves a dynamic phenomenological approach to the study of materials by observing the response of these materials to a change in temperature. This approach differs fundamentally from static methods of analysis, such as structural or chemical analyses, which rely on direct observations of a basic property of material (e.g. crystal structure or chemical composition) at a well-defined set of conditions (e.g. temperature, pressure, humidity). Clay minerals are highly susceptible to significant compositional changes in response to subtle changes in conditions. For example, changes in the fugacity of water affect the stability of interlayer H2O in a clay mineral (see below). Therefore, care must be taken that all experimental conditions are known with accuracy and precision
Baseline Studies of the Clay Minerals Society Source Clays: Cation Exchange Capacity Measurements by the Ammonia-Electrode Method
Authors: Borden D. , Giese R. F.
Published: June 2006

The cation exchange capacity (CEC) of fine-grained materials, and especially clay minerals, is a fundamental property of these materials, and can be determined routinely. A search of the recent literature illustrates the great interest of this property to researchers. For example, a search of the GeoRef database for references to “cation exchange capacity” for the years 1980 to 1999 yields 2559 citations.
Baseline Studies of the Clay Minerals Society Source Clays: Colloid and Surface Phenomena
Authors: Wu Wenju
Published: June 2006

The interface between the surfaces of clay minerals and other materials (aqueous solution, organic moieties, biomolecules, etc.) is of great importance to many geological, technological and biological processes. The examination of the structure and composition of mineral surfaces is advancing rapidly. However, the crystal structure of a mineral is only part of the information needed to understand the activity of the surface; we still do not fully understand the chemical and physical interactions at the surface or interface. One very powerful methodology for the study of surfaces and interfacial interactions is the determination of the thermodynamic properties of the surface. It became possible in the late 1980s to determine quantitatively the apolar and polar surface-tension components and parameters of liquids and solids (van Oss et al., 1988; van Oss, 1994), and the experimental techniques necessary for obtaining surface free-energy components of minerals, and particularly of colloid-sized minerals, are also a recent development (Costanzo eta!., 1990; van Oss et al., 1990, 1992; Giese et al., 1991).
Proteinase-mediated cell signalling: targeting proteinase-activated receptors (PARs) by kallikreins and more
Authors: Oikonomopoulou Katerina , Hansen Kristina K. , Saifeddine Mahmoud , Vergnolle Nathalie , Tea Illa , Diamandis Eleftherios P. , Hollenberg Morley D.
Published: June 2006

Serine proteinases, like trypsin, can play a hormone-like role by triggering signal transduction pathways in target cells. In many respects these hormone-like actions of proteinases can now be understood in terms of the pharmacodynamics of the G protein-coupled ‘receptor’ responsible for the cellular actions of thrombin (proteinase-activated receptor-1, or PAR1). PAR1, like the other three members of this receptor family (PAR2, PAR3and PAR4), has a unique mechanism of activation involving the proteolytic unmasking of an N-terminally tethered sequence that can activate the receptor. The selective activation of each PAR by short synthetic peptides representing these sequences has demonstrated that PAR1, PAR2and PAR4play important roles in regulating physiological responses ranging from vasoregulation and cell growth to inflammation and nociception. We hypothesise that the tissue kallikreins may regulate signal transduction via the PARs. Although PARs can account for many of their biological actions, kallikreins may also cause effects by mechanisms not involving the PARs. For instance, trypsin activates the insulin receptor and thrombin can act via a mechanism involving its non-catalytic domains. Based on the data we summarise, we propose that the kallikreins, like thrombin and trypsin, must now be considered as important ‘hormonal’ regulators of tissue function.
Human kallikrein 4: enzymatic activity, inhibition, and degradation of extracellular matrix proteins
Authors: Obiezu Chistina V. , Michael Iacovos P. , Levesque Michael A. , Diamandis Eleftherios P.
Published: June 2006

Human kallikrein 4 (hK4) is a member of the expanded family of human kallikreins, a group of 15 secreted proteases. While this protein has been associated with ovarian and prostate cancer prognosis, only limited functional information exists. Therefore, we have undertaken an investigation of its enzymatic properties regarding substrate preference, degradation of extracellular matrix proteins, and its inhibition by various inhibitors. We successfully expressed and purified active recombinant hK4 from supernatants of thePichia pastorisexpression system. This enzyme seems to cleave more efficiently after Arg compared to Lys at the P1 position and exhibits modest specificity for amino acids at positions P2 and P3. hK4 forms complexes with α1-antitrypsin, α2-antiplasmin and α2-macroglobulin. The protease mediates limited degradation of extracellular matrix proteins such as collagen I and IV, and more efficient degradation of the α-chain of fibrinogen. The cleavage of extracellular matrix proteins by hK4 suggests that this enzyme may play a role in tissue remodeling and cancer metastasis.
mRNA expression analysis of human kallikrein 11 (KLK11) may be useful in the discrimination of benign prostatic hyperplasia from prostate cancer after needle prostate biopsy
Authors: Scorilas Andreas , Gregorakis Alkiviades K.
Published: June 2006

Kallikrein 11 (KLK11,TLSP, hippostatin) is a member of the human kallikrein gene family, which includes PSA,KLK2and 12 other members, all localized on chromosome 19q13.4. The aim of this study was to investigate whetherKLK11expression could be used to discriminate prostate cancer (CaP) from benign prostatic hyperplasia (BPH) in needle prostate biopsies. We analyzed the expression of the prostate-type variant of theKLK11gene in 64 CaP and BPH tissues obtained by transrectal ultrasound-guided needle biopsy. Reverse transcription (RT), PCR and image analysis methodologies were developed and used. Of the 42 BPH tissues examined, only 10 (23.8%) were positive for prostate-typeKLK11expression, while of the 22 CaP patients, 12 (54.5%) wereKLK11-positive (p=0.025). Logistic regression and receiver operating characteristic curve analyses demonstrated thatKLK11expression has a significant discriminatory value (crude odds ratio=3.84,p=0.016; area under the curve, 0.65, 95% CI 0.51–0.80) between CaP and BPH in needle prostate biopsies.
Overexpression of the human tissue kallikrein genes KLK4, 5, 6, and 7 increases the malignant phenotype of ovarian cancer cells
Authors: Prezas Panagiotis , Arlt Matthias J.E. , Viktorov Petar , Soosaipillai Antoninus , Holzscheiter Leon , Schmitt Manfred , Talieri Maroulio , Diamandis Eleftherios P. , Krüger Achim , Magdolen Viktor
Published: June 2006

The human tissue kallikrein family of serine proteases (hK1–hK15 encoded by the genesKLK1–KLK15) is involved in several cancer-related processes. Accumulating evidence suggests that certain tissue kallikreins are part of an enzymatic cascade pathway that is activated in ovarian cancer and other malignant diseases. In the present study, OV-MZ-6 ovarian cancer cells were stably co-transfected with plasmids expressing hK4, hK5, hK6, and hK7. These cells displayed similar proliferative capacity as the vector-transfected control cells (which do not express any of the four tissue kallikreins), but showed significantly increased invasive behavior in anin vitroMatrigel invasion assay (p<0.01; Mann-Whitney U-test). Forin vivoanalysis, the cancer cells were inoculated into the peritoneum of nude mice. Simultaneous expression of hK4, hK5, hK6, and hK7 resulted in a remarkable 92% mean increase in tumor burden compared to the vector-control cell line. Five out of 14 mice in the ‘tissue kallikrein overexpressing’ group displayed a tumor/situs ratio greater than 0.198, while this weight limit was not exceeded at all in the vector control group consisting of 13 mice (p=0.017; χ2test). Our results strongly support the view that tumor-associated overexpression of tissue kallikreins contributes to ovarian cancer progression.
Perchlorate Accumulation and Potential Exposure from Durum Wheat Irrigated with Colorado River Water
Authors: Sanchez CA , Krieger RI , Valentin-Blasini L , Blount BC , Khandaker NR
Published: June 2006

The Colorado River is contaminated with low levels of perchlorate derived from aerospace-and defense-related fuel industries once located near the Las Vegas Wash. At sufficiently high doses, perchlorate can disrupt thyroid function by inhibiting uptake of iodide. Researchers have reported on the presence of perchlorate in lettuce (Lactuca sativa L.) grown in the lower Colorado River region. Recent work has demonstrated the potential for wheat (Triticum aestivum L.) to accumulate perchlorate when irrigated with perchlorate contaminated irrigation water in Texas. Over 45 000 ha of durum wheat (Triticum turgidum var. durum) are irrigated with Colorado River water in Arizona and California for the national and international pasta industries. Studies were conducted to determine perchlorate accumulation of wheat irrigated with Colorado River water. Perchlorate did accumulate in the above-ground plant components (982 to 3924 µg/kg dry weight (dw)) and roots (96 to 650 µg/kg dw) of immature durum wheat. For mature wheat, concentrations were greater in the stalk (490 µg/kg dw) compared to the spike (80 µ/kg dw). Most of the detectable perchlorate in the spike was in the rachis (125 µ/kg dw) and glumes (236 µ/kg dw). A majority of grain samples collected had perchlorate concentrations below levels of quantification by ion chromatography with tandem mass spectrometry (IC/MS/MS) (25<25 µg/kg dw. These results indicate potential exposure from the consumption of pasta products derived from durum wheat irrigated with Colorado River water are low relative to the reference dose adopted by USEPA.
Probing the Elastic-Plastic, Time-Dependent Stress Response of Test Fasteners Using Finite Element Analysis
Authors: Renauld ML , Lien H , Wilkening WW
Published: June 2006

The evolution of global and local stress/strain conditions in test fasteners under test conditions is investigated using elastic-plastic, time-dependent finite element analyses (FEA). For elastic-plastic response, tensile data from multiple specimens, material heats and test temperatures are integrated into a single, normalized flow curve from which temperature dependency is extracted. A primary creep model is calibrated with specimen- and fastener-based thermal relaxation data generated under a range of times, temperatures, stress levels, and environments. These material inputs are used in analytical simulations of experimental test conditions for several types of fasteners. These fastener models are constructed with automated routines and contact conditions prescribed at all potentially mating surfaces. Thermal or mechanical room temperature preloading, as appropriate for a given fastener, is followed by a temperature ramp and a dwell time at constant temperature. While the amount of thermal stress relaxation is limited for the conditions modeled, local stress states are highly dependent upon geometry (thread root radius, for example), preloading history and thermal expansion differences between the test fastener and test fixture. Benefits of this FE approach over an elastic methodology for stress calculation will be illustrated with correlations of stress corrosion cracking (SCC) initiation time and crack orientations in stress concentrations.
Mechanistic Studies of High-Temperature Crack Initiation in Single Crystal Materials
Authors: Busso EP , O'Dowd NP , Nikbin K
Published: June 2006

In this work, the results of mechanistic studies of surface crack initiation due to the coalescence of microcracks from casting defects are presented. Two approaches are considered; namely, a continuum damage (CD) one and another where a microvoid is explicitly introduced in the vicinity of a notch. In both cases, a rate-dependent crystallographic theory is relied upon to describe the visco-plastic behavior of the single crystal. The numerical studies are conducted on a notched compact tension (CT) specimen with and without a single casting defect, idealized as a cylindrical void close to the notch surface. CD predictions of the formation of surface cracks under constant far-field loading, linked to the nucleation and coalescence of microcracks from internal porosities, are obtained from a recently proposed mechanistic anisotropic void growth model. In the explicit-void modeling approach, the time to crack initiation under constant load has been predicted using a strain-based failure criterion. Finite element analysis of the CT specimen revealed that, due to the strong localization of inelastic strain at the void, a microcrack will initiate in the vicinity of the void rather than at the notch surface. The numerical results have also shown that the time to crack initiation depends strongly on the applied load level and the void location. These results and those obtained from the CD predictions are compared and discussed. The applicability of a failure assessment approach, based on the linear elastic stress intensity factor to predict the crack initiation time under creep loading, is also considered.
Can Habitat Alteration and Spring Angling Explain Largemouth Bass Nest Success?
Authors: Wagner Tyler , Jubar Aaron K. , Bremigan Mary T.
Published: June 2006

Largemouth bass Micropterus salmoides nest in shallow littoral areas, making them vulnerable to negative effects of habitat alteration due to development of lake shorelines and fishing during the spring nesting period. For instance, alteration of shorelines may reduce the quality and abundance of nesting habitat, and the high visibility of nests and the aggressive guarding behavior of nesting males increase their vulnerability to fishing. In 2004, we monitored nest distribution and success and quantified local nest habitat features, lakewide angler effort, and lakeshore development patterns in five Michigan lakes to determine the extent to which habitat alteration and fishing limit the number of nests that produce swim‐up fry. Lakes spanned a range of lakeshore dwelling densities (8–22 dwellings/km), allowing us to determine the extent to which nest success varies within and among lakes due to local (e.g., substrate and cover) and lakewide (e.g., dwellings/km and fishing effort) factors. Surprisingly, local habitat characteristics were not important determinants of the probability that a nest would produce swim‐up fry (P > 0.05). At the whole‐lake scale, however, nest success was negatively related to dwelling density; the probability of producing swim‐up fry declined from 0.77 in the lake with the lowest dwelling density to 0.45 in the lake with the highest dwelling density (P = 0.018). Lakewide estimates of angling effort could not explain the difference among lakes, indicating the likely importance of quantifying angling at finer spatial scales. Knowledge of the magnitude of anthropogenic effects and the spatial scale at which they operate is integral for the management of black bass Micropterus spp.
Promoting Physical Activity in a Low-Income Multiethnic District: Effects of a Community Intervention Study to Reduce Risk Factors for Type 2 Diabetes and Cardiovascular Disease
Authors: Jenum Anne Karen , Anderssen Sigmund A. , Birkeland Kåre I. , Holme Ingar , Graff-Iversen Sidsel , Lorentzen Catherine , Ommundsen Yngvar , Raastad Truls , Ødegaard Ann Kristin , Bahr Roald
Published: June 2006

OBJECTIVE—The aim was to assess the net effects on risk factors for type 2 diabetes and cardiovascular disease of a community-based 3-year intervention to increase physical activity.

RESEARCH DESIGN AND METHODS—A pseudo-experimental cohort design was used to compare changes in risk factors from an intervention and a control district with similar socioeconomic status in Oslo, Norway, using a baseline investigation of 2,950 30- to 67-year-old participants and a follow-up investigation of 1,776 (67% of those eligible, 56% women, 18% non-Western immigrants) participants. A set of theory-based activities to promote physical activity were implemented and tailored toward groups with different psychosocial readiness for change. All results reported are net changes (the difference between changes in the intervention and control districts). At both surveys, the nonfasting serum levels of lipids and glucose were adjusted for time since last meal.

RESULTS—The increase in physical activity measured by two self-reported questionnaires was 9.5% (P = 0.008) and 8.1% (P = 0.02), respectively. The proportion who increased their body mass was 14.2% lower in the intervention district (P < 0.001), implying a 50% relative reduction compared with the control district, and was lower across subgroups. Beneficial effects were seen for triglyceride levels (0.16 mmol/l [95% CI 0.06–0.25], P = 0.002), cholesterol–to–HDL cholesterol ratio (0.12 [0.03–0.20], P = 0.007), systolic blood pressure (3.6 mmHg [2.2–4.8], P < 0.001), and for men also in glucose levels (0.35 mmol/l [0.03–0.67], P = 0.03). The net proportion who were quitting smoking was 2.9% (0.1–5.7, P = 0.043).

CONCLUSIONS—Through a theory-driven, low-cost, population-based intervention program, we observed an increase in physical activity levels, reduced weight gain, and beneficial changes in other risk factors for type 2 diabetes and cardiovascular disease.
Risk of Progression to Type 2 Diabetes Based on Relationship Between Postload Plasma Glucose and Fasting Plasma Glucose
Authors: Abdul-Ghani Muhammad A. , Williams Ken , DeFronzo Ralph , Stern Michael
Published: June 2006

OBJECTIVE—We sought to assess the risk of progression to type 2 diabetes in normal glucose tolerance (NGT) subjects based on the relationship between the plasma glucose concentration during oral glucose tolerance tests (OGTTs) and the fasting plasma glucose (FPG) concentration.

RESEARCH DESIGN AND METHODS—Subjects with NGT (n = 1,282) from the San Antonio Heart Study received an OGTT with measurement of the plasma glucose concentration at 0, 30, 60, and 120 min at baseline and after 7–8 years of follow-up. Subjects were divided into four groups based on the relationship between the plasma glucose concentration during the OGTT and the FPG concentration on the same day as the OGTT. Insulin resistance was calculated by the homeostasis model assessment of insulin resistance (HOMA-IR) and Matsuda index. Early-phase insulin secretion was calculated as the ratio between the incremental plasma insulin and glucose concentrations during the first 30 min of the OGTT (ΔI0–30/ΔG0–30). Total insulin secretion was calculated as the ratio between the incremental areas under the insulin and glucose curves during the OGTT [ΔG(AUC)/ΔI(AUC)].

RESULTS—In 23 subjects (group I), the plasma glucose concentration during the OGTT returned to levels below the FPG concentration at 30 min; in 111 subjects (group II) and in 313 subjects (group III), the plasma glucose concentration during the OGTT returned to levels below the FPG concentration at 60 and 120 min, respectively. In the remaining 835 subjects (group IV), the plasma glucose concentration during the OGTT never fell below the FPG concentration. Insulin resistance, measured by HOMA-IR and the Matsuda index, increased progressively from group I through group IV, while insulin secretion measured by ΔI0–30/ΔG0–30 and ΔG(AUC)/ΔI(AUC) decreased progressively from group I through group IV. The incidence of type 2 diabetes was 0% in group I and progressively increased to 0.9% in group II, 3.2% in group III, and 6.4% in group IV.

CONCLUSIONS—Subjects whose postload plasma glucose concentration returned to baseline (i.e., FPG level) more quickly had greater insulin sensitivity, a higher insulinogenic index, and a lower risk of developing type 2 diabetes after 8 years of follow-up compared with subjects whose postload glucose concentration returned to baseline more slowly.
Is Nonalbuminuric Renal Insufficiency in Type 2 Diabetes Related to an Increase in Intrarenal Vascular Disease?
Authors: MacIsaac Richard J. , Panagiotopoulos Sianna , McNeil Karen J. , Smith Trudy J. , Tsalamandris Con , Hao Huming , Matthews P. Geoffrey , Thomas Merlin C. , Power David A. , Jerums George
Published: June 2006

OBJECTIVE—To investigate the role of intrarenal vascular disease in the pathogenesis of nonalbuminuric renal insufficiency in type 2 diabetes.

RESEARCH DESIGN AND METHODS—We studied 325 unselected clinic patients who had sufficient clinical and biochemical information to calculate an estimated glomerular filtration rate (eGFR) using the Modified Diet in Renal Disease six-variable formula, at least two estimations of urinary albumin excretion rates (AER), and a renal duplex scan to estimate the resistance index of the interlobar renal arteries. The resistance index, measured as part of a complications surveillance program, was compared in patients with an eGFR < or ≥60 ml/min per 1.73 m2 who were further stratified into normo- (AER <20), micro- (20–200), or macroalbuminuria (> 200 μg/min) categories.

RESULTS—Patients with an eGFR <60 ml/min per 1.73 m2 had a higher resistance index of the renal interlobar arteries compared with patients with an eGFR ≥60 ml/min per 1.73 m2. However, the resistance index was elevated to a similar extent in patients with an eGFR <60 ml/min per 1.73 m2 regardless of albuminuric status (normo- 0.74 ± 0.01, micro- 0.73 ± 0.01, and macroalbuminuria resistance index 0.75 ± 0.11). Multiple regression analysis revealed that increased age (P < 0.0001), elevated BMI (P = 0.0001), decreased eGFR (P < 0.01), and decreased diastolic blood pressure (P < 0.01), but not an increased AER, were independently associated with an elevated resistance index in patients with impaired renal function.

CONCLUSIONS—Subjects with type 2 diabetes and reduced glomerular filtration rate had similar degrees of intrarenal vascular disease, as measured by the intrarenal arterial resistance index, regardless of their AER status. The pathological mechanisms that determine the relationship between impaired renal function and AER status in subjects with type 2 diabetes remain to be elucidated.
Impact of Glycemic Control on Survival of Diabetic Patients on Chronic Regular Hemodialysis
Authors: Oomichi Takeshi , Emoto Masanori , Tabata Tsutomu , Morioka Tomoaki , Tsujimoto Yoshihiro , Tahara Hideki , Shoji Tetsuo , Nishizawa Yoshiki
Published: June 2006

OBJECTIVE—To investigate the impact of glycemic control during regular hemodialysis on the survival of diabetic patients with chronic kidney disease (CKD) in a longitudinal observational study.

RESEARCH DESIGN AND METHODS—A total of 114 diabetic CKD patients on hemodialysis at Inoue Hospital (Suita, Japan) were surveyed from May 1995 to December 2002 (survey period 45.5 ± 29.3 [means ± SD] months). All subjects were categorized into three groups by mean HbA1c (A1C) level during the 3-month period on hemodialysis preceding entry, as follows: good (A1C <6.5%, 5.7 ± 0.4%, n = 34), fair (6.5 ≤ A1C < 8.0%, 7.2 ± 0.4%, n = 39), and poor (A1C ≥8.0%, 9.2 ± 0.9%, n = 41) A1C groups.

RESULTS—There were no significant differences in age at entry, initiation of hemodialysis, duration of hemodialysis, blood pressure, cardiothoracic ratio, serum creatinine level, or hemoglobin level among the three groups. The cumulative survival of the poor A1C group during the survey was significantly lower than that of the fair and good A1C groups as determined by Kaplan-Meier estimation (P = 0.041, log-rank test). In a multivariate Cox proportional hazard model, both poor A1C group (hazard ratio 2.889, P = 0.010) and mean A1C (1.260 per 1.0%, P = 0.003) were significant predictors of survival.

CONCLUSIONS—In diabetic CKD patients on regular hemodialysis, poor glycemic control is an independent predictor of prognosis. This finding indicates the importance of careful management of glycemic control even after initiation of hemodialysis.