bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Determination of the Rates of Precipitation of Authigenic Illite and Kaolinite in the Presence of Aqueous Oxalate and Comparison to the K/Ar Ages of Authigenic Illite in Reservoir Sandstones
Authors: Small J. S. 
Published: August 2006

AbstractThe importance of precipitation rate as an effective control on illite and kaolanite formation during diagenesis has been examined by measuring precipitation rates, from Al fluid concentration, in a Dickson fluid-sampling vessel at 160°-250° and 500 bars (50 MPa). These experiments are considered to be analogues of the precipitation of clays in sandstones from porewaters containing dissolved carboxylic acids, which have a transient stability and may influence aluminosilicate solubility. Precipitated illite had a lath-shaped morphology and its composition was consistent with authigenic illite in sandstones. Kaolinite formed tabular rather than vermicular shaped crystals. Kaolinite precipitation rate was two orders of magnitude faster than illite precipitation and was rate-limited by the decomposition of oxalate; kaolinite formation should be equilibrium-controlled at virtually all stages of burial. Extrapolation of illite precipitation rate to burial temperatures indicates that the first appearance of illite in a burial sequence may be kinetically controlled. A model of illite precipitation based on these experimental results has been used to predict the time required to precipitate illite during burial of a sandstone, taking into account temperature changes during burial. For northern North Sea examples, a predicted illitization threshold of -60°C occurring at 60–80 Ma corresponds to the observed initiation of authigenic illite precipitation. Times of around 2–5 Ma would be required to reach a 98% approach to equilibrium at this threshold. The main phase of illite precipitation in the northern North Sea basin is a later, hydrologically controlled event (30-50 Ma). Equilibrium would be approached in around 0.1 Ma during this phase, which is consistent with the narrow illite K/Ar age range (1-5 Ma) recorded for some sequences.
Nature of the Illitic Phase Associated with Randomly Interstratified Smectite/Illite in Soils
Authors: Laird D. A. , Nater E. A. 
Published: August 2006

AbstractA dispersion-centrifugation-decantation procedure was used to isolate various particle size fractions from a sample of clay (<2 µm fraction) separated by sedimentation from the Ap horizon of a Webster soil (fine-loamy, mixed, mesic Typic Haplaquoll). The 0.02–0.06 µm size fraction was found to be enriched in an illitic phase associated with randomly interstratified smectite/illite. X-ray powder diffraction, chemical analysis, and high-resolution transmission electron microscopy confirmed that most of the illitic material in the 0.02–0.06 µm size fraction was composed of two-layer elementary illite particles with a layer charge of −0.47 per formula unit. The results demonstrate that this low-charge illitic phase can be physically separated from soil materials and that the low-charge illitic phase has chemical, morphological, and mineralogical properties that are uniquely different from those of smectite and illite.
Characterization of Colloidal Solids from Athabasca Fine Tails
Authors: Kotlyar L. S. , Deslandes Y. , Sparks B. D. , Kodama H. , Schutte R. 
Published: August 2006

AbstractDuring processing of Athabasca oil sands, the finely divided solids form an aqueous suspension, which ultimately stabilizes as a gel-like structure retaining up to 90% of the process water. This gelling phenomenon is believed to be caused by colloidal inorganic components. Kaolinite and mica are the main crystalline minerals in these colloidal solids; swelling clays are present in only trace amounts. Non-crystalline components are more concentrated in the finer fraction of the solids. Although the surfaces of the colloidal solids are virtually free of Fe, some contamination with polar organic matter is observed.
Characterization of Tubular Chrysotile by Thermoporometry, Nitrogen Sorption, Drifts, and TEM
Authors: Titulaer Mark K. , van Miltenburg J. Cees , Jansen J. Ben H. , Geus John W. 
Published: August 2006

AbstractThe maximum crystal radius Rn of ice in hollow wet chrysotile tubes is established by thermoporometry to be between 2.8 and 3.2 nm, and the internal pore volume Vn of the tubes to be between 0.008 and 0.02 ml/g. The hollow tubes of chrysotile and, for comparative reasons, small plates of talc, are hydrothermally synthesized at temperatures between 563 and 600 K and at pressures between 75 and 120 hPa. Size and shape of the pores can be varied by changing the Mg/Si molar ratios in steps of 3/1.5 and 3/2 for chrysotile and 3/3.6 and 3/4 for talc. The tubular morphology of the aggregates dried at 393 K is investigated by 1) transmission electron microscopy (TEM), 2) nitrogen adsorption and desorption at 77 K, and 3) diffuse reflectance infrared fourier transformed spectroscopy (DRIFTS). The radius within the hollow tubes, Ri, is between 2.5 and 4.0 nm as measured by TEM, and between 2.8 and 3.2 nm as determined by nitrogen adsorption and desorption. The measured radii agree well with the value calculated from crystallographic data, which is smaller than 5.3 nm. Within the dried aggregates the tubes are clustered in regular patterns, in which each tube is surrounded by six other tubes. The external radius, Ro, between the clustered tubes is from 1.6 to 2.9 nm as observed by TEM, and from 1.8 to 2.3 nm by N2 adsorption and desorption. The external radius is not measured by thermoporometry. Where thermoporometry only measures the average pore size and pore volume within the tubes, TEM and N2 adsorption and desorption additionally provide the corresponding values between the tubes. A third pore radius, 5 to 20 nm between the clusters of chrysotile tubes, is established with N2 adsorption and desorption.
Residual Manganese(II) Entrapped in Single-Layer-Hydrate Montmorillonite Interlayers
Authors: Gehring A. U. , Fry I. V. , Lloyd T. , Sposito G. 
Published: August 2006

AbstractElectron paramagnetic resonance (EPR) and Fourier transform infrared (FTIR) spectroscopy in combination with X-ray diffractometry and thermal methods were used to determine the coordination of residual exchangeable Mn(II) in an untreated sample of Wyoming montmorillonite. At room temperature, Mn(II) in a single-layer-hydrate interlayer was proposed to be coordinated directly with oxygen ions of the siloxane surface on one layer and to form water bridges to the oxygens on the siloxane surface of the opposite layer. Dehydration and collapse of the interlayer entrapped and thereby stabilized the partially solvated Mn(II) up to 600°C. A change to Mn(II) in highly symmetric coordination occurred during dehydroxylation of the montmorillonite structure between 600°C and 700°C. Manganese(II) remained coordinated at the surface but positioned in a bicapped trigonal antiprism formed by oxygens of the silicate structure. This coordination was metastable at 800°C when the structural decomposition of the clay mineral began.
Isothermal Treatments of Regularly Interstratified Montmorillonite-Beidellite at Hydrothermal Conditions
Authors: Yamada Hirohisa , Nakazawa Hiromoto 
Published: August 2006

AbstractA glass in the intermediate composition of montmorillonite and beidellite, 50/50 in mole ratio, was treated under a hydrothermal pressure of 100 MPa, in the temperature range from 250 to 500°C and durations from 2 to 129 days. The phases identified in the products were plotted in a time-temperature-transformation (TTT) diagram. The TTT diagram showed that the regularly interstratified montmorillonite-beidellite (r.i.M-B) was a metastable phase above the temperature of 350°C and changed to the assemblage of Na-rectorite + saponite + quartz, through the intermediate assemblage of beidellite + saponite + quartz. The TTT diagram suggested also that the r.i.M-B might be a stable clay mineral below the temperature of 300°C in the middle region of montmorillonite-beidellite pseudo-binary system, although the laboratory confirmation of the mineral stability was not easy for the sluggish reaction.
Synthesis and CO2 Adsorption Features of a Hydrotalcite-Like Compound of the Mg2+-Al3+-Fe(CN)64- System with High Layer-Charge Density
Authors: Mao Gang , Tsuji Masamichi , Tamaura Yutaka 
Published: August 2006

AbstractHydrotalcite-like compounds (HT) with 24%–48% Al3+-substitution have been synthesized in the Mg2+-Al3+-Fe(CN)64- system. Conditioning of the synthesized and air-dried compound with K4Fe(CN)64- solution at 80°C was essential to obtain the 80%–90% pure ionic Fe(CN)64- form on an equivalent basis. A linear decrease in ao with an increase in the mole ratio of R = Al3+/(Mg2+ + Al3+) was extended to R = 0.48. The formation of highly Al3+-substituted HTs has been corroborated by the decrease in the hexagonal lattice constant ao down to 3.016 Å. The ao value was independent of the interlayer anions. The CO2 adsorption profiles were dependent upon both the Al3+-substitution and the interlayer distance. The isosteric heat of CO2 adsorption was 43.3 kJ mol-1 in the range of adsorption of 20 to 40 cm3 g-1 at 298 K and 0.1 MPa.
Diabetes, Inflammation, and Functional Decline in Older Adults
Authors: Figaro M. Kathleen , Kritchevsky Stephen B. , Resnick Helaine E. , Shorr Ronald I. , Butler Javed , Shintani Ayumi , Penninx Brenda W. , Simonsick Eleanor M. , Goodpaster Bret H. , Newman Anne B. , Schwartz Ann V. , Harris Tamara B. ,   for the Health Aging and Body Composition study
Published: August 2006

OBJECTIVE—Age, diabetes, and elevated inflammatory markers independently increase the risk of functional decline. We examined the effect of C-reactive protein (CRP) and interleukin-6 (IL-6) on the incident mobility limitation in older adults with and without diabetes.
RESEARCH DESIGN AND METHODS—We analyzed data from a cohort of 2,895 well-functioning adults aged 70–79 years, followed for development of persistent functional limitation over 3.5 years. Participants were assessed for the presence of diabetes according to fasting glucose and/or hypoglycemic medication use and were divided into three equal groups (tertiles) according to level of CRP or IL-6. Persistent functional limitation was defined as difficulty climbing 10 steps or walking one-quarter mile on two consecutive semiannual assessments.
RESULTS—At baseline, 702 participants (24%) had diabetes. CRP values were (median ± SD) 2.8 ± 4.4 versus 3.7 ± 5.4 for those with normal glucose and diabetes, respectively (P &lt; 0.001). The unadjusted incidence of functional limitation associated with increased levels of CRP and IL-6 was greater among participants with diabetes. After adjusting for clinical and demographic covariates, persistent functional limitation for the highest tertile was greater compared with that for the lowest tertile of CRP or IL-6 for those with and without diabetes. CRP hazard ratios (HRs) were 1.7 (95% CI 1.2–2.3) versus 1.4 (1.1–1.6), respectively. IL-6 HRs were 1.8 (1.3–2.5) versus 1.6 (1.4–2.0), respectively.
CONCLUSIONS—In initially high-functioning older adults, those with diabetes and higher inflammatory burden had an increased risk of functional decline. Interventions at early stages to reduce inflammation may preserve function in these individuals.
Erythropoietin Is Expressed in the Human Retina and It Is Highly Elevated in the Vitreous Fluid of Patients With Diabetic Macular Edema
Authors: Hernández Cristina , Fonollosa Alex , García-Ramírez Marta , Higuera Mónica , Catalán Roberto , Miralles Adela , García-Arumí José , Simó Rafael 
Published: August 2006

OBJECTIVE—Erythropoietin has been recently found to be increased in the vitreous fluid from ischemic retinal diseases such as proliferative diabetic retinopathy (PDR). The aims of the present study were 1) to measure erythropoietin levels in the vitreous fluid from patients with diabetic macular edema (DME), a condition in which the ischemia is not a predominat event, and 2) to compare erythropoietin mRNA expression between human retinas from nondiabetic and diabetic donors without retinopathy.
RESEARCH DESIGN AND METHODS—Vitreous samples from 12 type 2 diabetic patients with DME without significant retinal ischemia and 12 PDR patients were prospectively analyzed. Ten nondiabetic patients with macular holes served as the control group. Erythropoietin was assessed by radioimmunoassay (milliunits per milliliter). Erythropoietin mRNA expression was measured by quantitative real-time RT-PCR analysis in the retina from eight nondiabetic and eight age-matched diabetic donors without diabetic retinopathy
RESULTS—Intravitreal erythropoietin concentration was higher in both PDR and DME patients than in nondiabetic control subjects (PDR vs. control subjects: median 302 [range 117–1,850] vs. 30 mU/ml [10–75], P &lt; 0.01; DME vs. control subjects: 430 [41–3,000] vs. 30 mU/ml [10–75], P &lt; 0.01). However, no significant differences were found between DME and PDR patients. Erythropoietin mRNA expression was detected in the human retina, and it was higher in the retina from diabetic than from nondiabetic donors.
CONCLUSIONS—As occurs in PDR, intravitreous erythropoietin concentrations are strikingly higher in DME. Erythropoietin is expressed in the human retina, and it is upregulated in diabetic patients even without retinopathy. These findings suggest that other factors apart from ischemia are involved in the overexpression of erythropoietin in diabetic retinopathy.
Elevated fibrinogen fragment levels in uremic plasma inhibit platelet function and expression of glycoprotein IIb‐IIIa
Authors: Thekkedath Usha R. , Chirananthavat Thanit , Leypoldt John K. , Cheung Alfred K. , Mohammad Syed F. 
Published: August 2006

AbstractHemostatic dysfunction is frequently noted in uremia, but the mechanisms responsible for it are poorly understood and are assumed to be multifactorial. Preliminary findings from our laboratory suggest that elevated levels of circulating fibrinogen fragments (FF) might contribute to the hemostatic defect in uremic patients. Defibrinated plasma obtained from chronic hemodialysis (HD) patients as well as normal subjects were examined by SDS‐PAGE and immunoblotting and quantified by an immunoassay. In addition, endogenous FF isolated from normal and uremic plasma using affinity chromatography were examined by flow cytometry for their effect on glycoprotein (GP) IIb‐IIIa receptor expression and tested for their ability to inhibit platelet aggregation. The mean FF concentration in uremic plasma (1.14 ± 0.85 mg/ml) was noted to be eight times greater than in normal plasma (0.15 ± 0.01 mg/ml) (P < 0.05). Moreover, the mean FF level decreased by 48.25% following HD (from 1.14 ± 0.85 mg/ml to 0.59 ± 0.33 mg/ml; P < 0.05). SDS‐PAGE and immunoblotting experiments showed that the decrease was observed in both medium‐sized (20–60 kDa) as well as large (>100 kDa) FF. Further, FF isolated from uremic plasma inhibited platelet aggregation by (46.8 ± 18.1)% (P < 0.05) and the GP IIb‐IIIa receptor expression by (28.0 ± 7.6)% (P < 0.05 vs. control). The results show that (1) FF levels are elevated in uremic plasma, (2) HD results in significant decrease in FF and (3) endogenous FF inhibit platelet function, presumably via competitive binding to the fibrinogen receptor GP IIb‐IIIa. The decrease in plasma levels of FF > 100 kDa following HD suggests that adsorption to the dialysis membrane contributes to their removal. Am. J. Hematol., 2006. © 2006 Wiley‐Liss, Inc.
Inherited thrombophilia is associated with deep vein thrombosis in a Colombian population
Authors: Torres J.D. , Cardona H. , Álvarez L. , Cardona‐Maya W. , Castañeda S.A. , Quintero‐Rivera F. , Cadavid A. , Bedoya G. , Tobón L. 
Published: August 2006

AbstractThe development of venous thromboembolism is influenced by a variety of genetic and environmental risk factors. A few studies have ascertained whether thrombophilic defects are risk factors for venous thromboembolism in Latin American populations with a variable degree of admixture, such as the Colombian population. To address this issue, we conducted a case–control study involving 100 consecutive patients with deep vein thrombosis and 114 healthy controls from the Hospital Universitario San Vicente de Paúl, Medellín, Colombia. Activated protein C resistance (APC resistance) was detected in 25/99 patients vs. 6/114 controls (OR = 6.08, 95% CI = 2.23–17.47). Ten of 100 patients carried the factor V Leiden mutation vs. 1/114 controls (OR = 12.56, 95% CI = 1.61–267). APC resistance was associated with the factor V Leiden mutation in only 10/25 patients. The prothrombin G20210A mutation was found in 4/100 patients, but none of the controls (P < 0.05). There was no significant difference in the proportion of homozygous carriers of methylenetetrahydrofolate reductase C677T variant among patients and controls. In conclusion, in our studied population, factor V Leiden, APC resistance, and prothrombin G20210A were associated with an increased risk of deep vein thrombosis. However, the frequencies of these thrombophilic defects and of APC resistance associated with factor V Leiden was lower than the corresponding frequencies previously reported for Caucasian populations. Further study is required to assess the influence of ethnicity on thrombophilia. Am. J. Hematol., 2006. © 2006 Wiley‐Liss, Inc.
A genome‐wide linkage search for bipolar disorder susceptibility loci in a large and complex pedigree from the eastern part of Cuba
Authors: Marcheco‐Teruel B. , Flint T.J. , Wikman F.P. , Torralbas M. , González L. , Blanco L. , Tan Q. , Ewald H. , Orntoft T. , Kruse T.A. , Børglum A.D. , Mors O. 
Published: August 2006

AbstractWe present results from a genome‐wide scan of a six generation pedigree with 28 affected members with apparently dominant bipolar I disorder from eastern Cuba. Genotypes were obtained using the early access version of the Genechip Mapping 10K Xba array from AFFYMETRIX. Parametric and non‐parametric linkage analyses under dominant and recessive models were performed using GENEHUNTER v2.1r5. Two phenotypic models were included in the analyses: bipolar I disorder and recurrent depressive disorder, or bipolar I disorder only. LOD scores were calculated for the entire family combined, and for four subdivisions of the family. For the entire family a suggestive parametric LOD score was obtained under the dominant model and the broader phenotype at 14q11.2‐12 (LOD = 2.05). In the same region, a non‐parametric LOD score close to genome‐wide significance was also obtained, based on the entire family (NPL = 7.31,P‐value = 0.07). For two individual branches of the pedigree, genome‐wide significance (P < 0.005) was obtained with NPL scores of 8.71 and 12.99, respectively, also in the same region on chromosome 14. Chromosome 5q21.3‐22.3 also showed close to genome‐wide significant linkage for the complete pedigree (NPL = 7.26,P = 0.07), also supported by significant linkage in one individual branch (NPL = 9.86,P < 0.005). In addition, genome‐wide significant nonparametric results (P‐values <0.005) were obtained for individual branches at 5p13.1‐q12.3, 6p22.3, 8q13.3‐21.13, and 10q22.3‐23.32. Finally, 2p25.1‐25.3, 2p13.3‐14, 3p14.2, 6p22.3‐24.1, 7p14.1‐14.2, 8q12.2‐12.3, 10q21.1‐21.2, 14q13.1‐21.1, 15q15.1‐21.2, and 22q12.3‐13.32 showed suggestive linkage in the complete family. Most of these potential susceptibility loci overlap with, or are close, to previous linkage findings. The locus on 5q may, however, represent a novel susceptibility locus. © 2006 Wiley‐Liss, Inc.
Absence of association with DAT1 polymorphism and response to methylphenidate in a sample of adults with ADHD
Authors: Mick Eric , Biederman Joseph , Spencer Thomas , Faraone Stephen V. , Sklar Pamela 
Published: August 2006

AbstractA polymorphism in the dopamine transporter gene (DAT1) has been previously associated with ADHD and methylphenidate has been hypothesized to block the dopamine transporter. The goal of this study was to examine whether a 40‐bp variable number of tandem repeats (VNTR) of DAT1 moderate response and adverse effects associated with methylphenidate treatment of adults with ADHD. Subjects were 106 adults with ADHD enrolled in 6‐week randomized placebo‐controlled parallel design trials of methylphenidate (OROS and immediate release preparations). There was no evidence of an association between DAT1 VNTR and response to methylphenidate (F(2,100) = 0.04, P = 0.9). Similarly, there was no pattern of statistically significant association with DAT1 VNTR and cardiovascular or spontaneously reported adverse effects. We failed to identify an association with DAT1 and the response or tolerability of methylphenidate in adults with ADHD. © 2006 Wiley‐Liss, Inc.
Possible role of preproghrelin gene polymorphisms in susceptibility to bulimia nervosa
Authors: Ando Tetsuya , Komaki Gen , Naruo Tetsuro , Okabe Kenjiro , Takii Masato , Kawai Keisuke , Konjiki Fujiko , Takei Michiko , Oka Takakazu , Takeuchi Kaori , Masuda Akinori , Ozaki Norio , Suematsu Hiroyuki , Denda Kenzo , Kurokawa Nobuo , Itakura Kotarou , Yamaguchi Chikara , Kono Masaki , Suzuki Tatsuyo , Nakai Yoshikatsu , Nishizono‐Maher Aya , Koide Masanori , Murakami Ken , Nagamine Kiyohide , Tomita Yuichiro , Ookuma Kazuyoshi , Tomita Kazumi , Tonai Eita , Ooshima Akira , Ishikawa Toshio , Ichimaru Yuhei 
Published: August 2006

AbstractPrevious investigations have suggested that ghrelin, an endogenous orexigenic peptide, is involved in the pathology of eating disorders. We conducted a study to determine whether any preproghrelin gene polymorphisms are associated with eating disorders. Three hundred thirty‐six eating disorder patients, including 131 anorexia nervosa (AN)‐restricting types (AN‐R), 97 AN‐binge eating/purging types (AN‐BP) and 108 bulimia nervosa (BN)‐purging types (BN‐P), and 300 healthy control subjects participated in the study. Genotyping was performed to determine the polymorphisms present, and with this information, linkage disequilibrium (LD) between the markers was analyzed and the distributions of the genotypes, the allele frequencies, and the haplotype frequencies were compared between the groups. The Leu72Met (408 C > A) (rs696217) polymorphism in exon 2 and the 3056 T > C (rs2075356) polymorphism in intron 2 were in LD (D′ = 0.902, r2 = 0.454). Both polymorphisms were significantly associated with BN‐P (allele‐wise: P = 0.0410, odds ratio (OR) = 1.48; P = 0.0035, OR = 1.63, for Leu72Met and 3056 T > C, respectively). In addition, we observed a significant increase in the frequency of the haplotype Met72‐3056C in BN‐P patients (P = 0.0059, OR = 1.71). Our findings suggest that the Leu72Met (408 C > A) and the 3056 T > C polymorphisms of the preproghrelin gene are associated with susceptibility to BN‐P. © 2006 Wiley‐Liss, Inc.