bluuebunny/crossref_metadata_2025_split huggingface dataset:
New occurrence and characterization of Ni-serpentines in the Kwangcheon area, Korea
Authors: Song Y. , Moon H-S. , Chon H-T. 
Published: November 2006

AbstractPecoraite and nepouite, Ni-serpentines, occur in the serpentinized ultramafic rocks in the Kwangcheon area, Korea, where the parent rock is classified as harzburgite and/or lherzolite. Pecoraite was precipitated twice from the solution; the early-formed pecoraite coexists with magnetite, millerite, and polydymite both in the Buk- and Nam-sites, while the late-formed pecoraite appears as well-grown colloform and opaque-free phase only in the Buk-site. The typical colloform texture of the late-formed pecoraite strongly indicates that it was precipitated from the solution in supergene conditions. Pecoraite is characterized by its extremely high Ni content and the difference in Fe content between the early- and late-formed pecoraite. Nepouite is distinguished from pecoraite by its prismatic morphology and the large degree of isomorphous substitution between Ni and Mg. The phase relations among coexisting magnetite-millerite-polydymite assemblage with the early-formed pecoraite suggest that the pecoraite might have precipitated in the extremely limited fO2 and fs2 environment from the highly Ni-concentrated solutions and is stable at 25°C and 1 bar.
An approach to the genesis of palygorskite in a Neogene-Quaternary continental basin using principal factor analysis
Authors: Sánchez C. , Galán E. 
Published: November 2006

AbstractThe Carrión lacustrine basin (≈10 km2), central Spain, is filled with Neogene-Quaternary sediments (20–25 m thick) rich in palygorskite. Two clay units of ∼15 m thick are of particular interest in the basin. The lower one contains over 75% phyllosilicates (palygorskite up to 90%, smectites and illite) in marginal areas (facies A), and it is laterally bound by a distal facies (B) also rich in clay minerals (smectites and illite, and some palygorskite) and gypsum, and includes dolomitic marl intercalations. The composition at the top is primarily marly, with some gypsum (C). The upper clay unit, mainly clay-size material, (D) is rich in smectites, palygorskite and sepiolite, and contains carbonate intercalations near the top. A statistical treatment of the mineralogical and chemical composition data from 120 samples, using principal factor analysis, suggests that: (a) illite and smectite are detrital in origin; (b) palygorskite was formed by transformation of illite and smectite involving reaction with Mg; and (c) sepiolite was a neoformation product favoured by evaporation of silica- and Mg-bearing waters.
Aluminium phosphate mineralization from the hypogene La Vanguardia kaolin deposit (Chile)
Authors: Dill H. G. , Fricke A. , Henning K.-H. , Theune C. H. 
Published: November 2006

AbstractIn the region of Illapel, Chile, dioritic and andesitic rocks of Cretaceous to Paleocene age from the Unidad San Lorenzo Formation have suffered strong alteration resulting in the formation of a kaolin-rich zone, which is mined in the La Vanguardia open pit near Combarbalá. Detailed mineralogical and chemical investigations of channel samples from this mine, involving a combination of optical microscopy, XRD, SEM-EDX, XRF and TEM, permitted recognition of a zone of silicification and a zone of advanced argillic alteration, both of which contain alunite s.s. and aluminium-phosphate-sulphate (APS) minerals of the woodhouseite group with subordinate amounts of gorceixite, florencite and goyazite. These minerals are found to have originated from infiltration of meteoric waters. The passage from silicification into advanced argillic alteration was associated with an increase in sulphate activity as manifested by the increase of SO42— at the expense of PO43— in the alunite s.s. and by an increase of the Au content from 0.01 to 0.03 mg/kg Au. This high sulphidation type of wallrock alteration may be roughly compared with the Nansatu type of White (1991).
Definition of clay and clay mineral: joint report of the AIPEA and CMS Nomenclature Committees
Authors: Guggenheim s. , Martin R. T. 
Published: November 2006

AbstractThe definition of ‘clay’ was first formalized in 1546 by Agricola. It has been revised many times since, although the fundamentals involving plasticity, particle size, and hardening on firing were retained by most. For an exhaustive account of the history of the definition to 1963, the reader is referred to Mackenzie (1963). More recent developments may be found in Weaver (1989).The definition of clay raises the important issue of clay constituents and, implicitly, the definition of ‘clay mineral'. Mackenzie (1963, p. 15) noted the inappropriateness of defining clay mineral as “any mineral which occurs in clay” since, among several reasons, it would include many accessory minerals that are not characteristic of clay.
Dehydration and rehydration of vermiculites: II. Phlogopitic Ca-vermiculite
Authors: Graf v. Reichenbach H. , Beyer J. 
Published: November 2006

AbstractDehydration and rehydration of a phlogopitic Ca-vermiculite were studied by thermoanalysis (TG, DSC) and by in situ X-ray powder diffractometry. A detailed analysis of the relationship between temperature and state of hydration of the vermiculite close to equilibrium at atmospheric pressure was rendered possible by use of low heating rates in combination with a fast recording position-sensitive detector. The results reveal the existence of a number of distinct states of hydration characterized by basal spacings of 1.515, 1.493, 1.473, 1.188, 1.176 and 0.95 nm. In confirmation of results obtained earlier with Mg-vermiculite, regular interstratification occurred at dehydration during the transition between two- to one- and between one- to zero-layer hydrates showing integral series of 00l reflections with basal spacings of 2.67 and 2.11 nm, respectively.
Etude d'une nacrite intercalée par du dimethylsulfoxide et n-methylacetamide
Authors: Ben Haj Amara A. , Ben Brahim J. , Besson G. , Pons C.H. 
Published: November 2006

ResumeUne nacrite est intercalée par deux composés organiques polaires: le diméthylsulfoxide (DMSO) et le n-méthylacétamide (NMA). Les deux solvants ont des moments dipolaires très voisins (4 debyes) mais des constantes diélectriques différentes (49 pour le DMSO et 179 pour le NMA). L'intercalation du NMA est plus rapide que celle du DMSO. Les deux complexes homogènes obtenus sont étudiés par diffraction des rayons X, spectroscopie infrarouge et ATD. L'étude par spectroscopie IR a montré que la nacrite expansée par du DMSO se comporte comme la kaolinite expansée par le même solvant. Dans le cas de la nacrite intercalée par du NMA, trois nouvelles bandes d'absorption dues aux vibrations de valence des OH liés par pont hydrogène avec le groupement C=O et situées respectivement à 3500, 3543 et 3589 cm−1 apparaissent. La fréquence v(N-H) du NMA est intermédiaire entre celles du liquide et d'une solution diluée, indiquant une liaison par pont hydrogène probablement avec les oxygènes de la couche tétraédrique du silicate. La diffraction des rayons X sur des échantillons orientés nous a permis d'obtenir 13 réflexions 00l pour chaque complexe. Une étude quantitative, par transformée de Fourier monodimensionnelle dans la direction perpendiculaire au plan du feuillet, a permis de déterminer le nombre de molécules organiques intercalées (une molécule par Si2Al2O5(OH)4) et leur orientation dans l'espace interlamellaire. L'ATD a montré par ailleurs que le complexe Nac.DMSO est plus stable que le complexe Nac.NMA.
Acid activation of a Spanish sepiolite: II. Consideration of kinetics and physico-chemical modifications generated
Authors: Vicente Rodriguez M.A. , Lopez Gonzalez J.D. , Bañares Muñoz M.A. , Casado Linarejos J. 
Published: November 2006

AbstractSepiolite from Vallecas (Spain) was treated with HCl solutions (1.25; 2.5; 5.0; 10.0 and 20.0 wt%) at 25°C for 2, 6, 24 and 48 h. The solutions obtained after washing the acid treated samples were analysed and a kinetic model was applied to the cation dissolution data. The development of porosity and number of acid centres was studied. The experimental conditions which yield products with the highest surface activity were established. The size of the silica fibres, obtained after the treatment, decreases when the intensity of the treatments is increased. These characteristics are important for the adsorptive properties and the catalytic potential of a solid.
Fibrous clays in the Almazan Basin (Iberian Range, Spain): genetic pattern in a calcareous lacustrine environment
Authors: Lopez-Aguayo F. , Gonzalez Lopez J. M. 
Published: November 2006

AbstractThe Tertiary sediments of the southern part of Almazán basin (Province of Soria) exhibit two different facies with a sharp transition between them: (1) a coarse detrital facies; and (2) a lutite and carbonate facies. The vertical evolution of these facies in the different sections and boreholes is made up of several retrograde depositional sequences which evolve from proximal alluvial fans to carbonate lacustrine systems associated with the most distal fan sediments.The variation of the mineralogical association (carbonates, quartz, detrital clay minerals, palygorskite and, occasionally, sepiolite and smectites) allows four ‘mineralogical facies’ to be established. Each facies has a distinctive mineralogy related to the main genetic processes: (1) detrital facies; (2) transitional facies; (3) ‘chemical dolomite-palygorskite’ facies and (4) ‘chemical calcite’ facies. Although the carbonates (calcite and dolomite) are always the most abundant minerals, fibrous clay minerals are also important. The main mechanism of mineral authigenesis in this basin is chemical precipitation; the presence and distribution of carbonates and fibrous clay minerals is controlled by the relative concentrations of [Mg2+], [Ca2+], pCO2, pH and [SiO4H4]. Palygorskite occurrences, in these conditions, are related to dissolution-precipitation mechanisms of pre-existing detrital material.
Ideal timing to transfer from an acute care hospital to an interdisciplinary inpatient rehabilitation program following a stroke: an exploratory study
Authors: Gagnon Dany , Nadeau Sylvie , Tam Vincent 
Published: November 2006

Abstract
Background
Timely accessibility to organized inpatient stroke rehabilitation services may become compromised since the demand for rehabilitation services following stroke is rapidly growing with no promise of additional resources. This often leads to prolonged lengths of stays in acute care facilities for individuals surviving a stroke. It is believed that this delay spent in acute care facilities may inhibit the crucial motor recovery process taking place shortly after a stroke. It is important to document the ideal timing to initiate intensive inpatient stroke rehabilitation after the neurological event. Therefore, the objective of this study was to examine the specific influence of short, moderate and long onset-admission intervals (OAI) on rehabilitation outcomes across homogeneous subgroups of patients who were admitted to a standardized interdisciplinary inpatient stroke rehabilitation program.

Methods
A total of 418 patients discharged from the inpatient neurological rehabilitation program at the Montreal Rehabilitation Hospital Network after a first stroke (79% of all cases reviewed) were included in this retrospective study. After conducting a matching procedure across these patients based on the degree of disability, gender, and age, a total of 40 homogeneous triads (n = 120) were formed according to the three OAI subgroups: short (less than 20 days), moderate (between 20 and 40 days) or long (over 40 days; maximum of 70 days) OAI subgroups. The rehabilitation outcomes (admission and discharge Functional Independence Measure scores (FIM), absolute and relative FIM gain scores, rehabilitation length of stay, efficiency scores) were evaluated to test for differences between the three OAI subgroups.

Results
Analysis revealed that the three OAI subgroups were comparable for all rehabilitation outcomes studied. No statistical difference was found for admission (P = 0.305–0.972) and discharge (P = 0.083–0.367) FIM scores, absolute (P = 0.533–0.647) and relative (P = 0.496–0.812) FIM gain scores, rehabilitation length of stay (P = 0.096), and efficiency scores (P = 0.103–0.674).

Conclusion
OAI does not seem to affect significantly inpatient stroke rehabilitation outcomes of patients referred from acute care facilities where rehabilitation services are rapidly initiated after the onset of the stroke and offered throughout their stay. However, other studies considering factors such as the type and intensity of the rehabilitation are required to support those results.
Feeding and fasting controls liver expression of a regulator of G protein signaling (Rgs16) in periportal hepatocytes
Authors: Huang Jie , Pashkov Victor , Kurrasch Deborah M , Yu Kan , Gold Stephen J , Wilkie Thomas M 
Published: November 2006

AbstractBackgroundHeterotrimeric G protein signaling in liver helps maintain carbohydrate and lipid homeostasis. G protein signaling is activated by binding of extracellular ligands to G protein coupled receptors and inhibited inside cells by regulators of G protein signaling (RGS) proteins. RGS proteins are GTPase activating proteins, and thereby regulate Gi and/or Gq class G proteins. RGS gene expression can be induced by the ligands they feedback regulate, and RGS gene expression can be used to mark tissues and cell-types when and where Gi/q signaling occurs. We characterized the expression of mouse RGS genes in liver during fasting and refeeding to identify novel signaling pathways controlling changes in liver metabolism.ResultsRgs16 is the only RGS gene that is diurnally regulated in liver ofad libitumfed mice. Rgs16 transcription, mRNA and protein are up regulated during fasting and rapidly down regulated after refeeding. Rgs16 is expressed in periportal hepatocytes, the oxygen-rich zone of the liver where lipolysis and gluconeogenesis predominates. Restricting feeding to 4 hr of the light phase entrained Rgs16 expression in liver but did not affect circadian regulation of Rgs16 expression in the suprachiasmatic nuclei (SCN).ConclusionRgs16 is one of a subset of genes that is circadian regulated both in SCN and liver. Rgs16 mRNA expression in liver responds rapidly to changes in feeding schedule, coincident with key transcription factors controlling the circadian clock. Rgs16 expression can be used as a marker to identify and investigate novel G-protein mediated metabolic and circadian pathways, in specific zones within the liver.
Effects of nerve growth factor (NGF) on blood vessels area and expression of the angiogenic factors VEGF and TGFbeta1 in the rat ovary
Authors: Julio-Pieper Marcela , Lara Hernán E , Bravo Javier A , Romero Carmen 
Published: November 2006

Abstract

Background
Angiogenesis is a crucial process in follicular development and luteogenesis. The nerve growth factor (NGF) promotes angiogenesis in various tissues. An impaired production of this neurotrophin has been associated with delayed wound healing. A variety of ovarian functions are regulated by NGF, but its effects on ovarian angiogenesis remain unknown. The aim of this study was to elucidate if NGF modulates 1) the amount of follicular blood vessels and 2) ovarian expression of two angiogenic factors: vascular endothelial growth factor (VEGF) and transforming growth factor beta 1 (TGFbeta1), in the rat ovary.

Results
In cultured neonatal rat ovaries, NGF increased VEGF mRNA and protein levels, whereas TGFbeta1 expression did not change. Sectioning of the superior ovarian nerve, which increases ovarian NGF protein content, augmented VEGF immunoreactivity and the area of capillary vessels in ovaries of prepubertal rats compared to control ovaries.

Conclusion
Results indicate that NGF may be important in the maintenance of the follicular and luteal vasculature in adult rodents, either indirectly, by increasing the expression of VEGF in the ovary, or directly via promoting the proliferation of vascular cells. This data suggests that a disruption on NGF regulation could be a component in ovarian disorders related with impaired angiogenesis.
Evaluation of methods for extraction of the volitional EMG in dynamic hybrid muscle activation
Authors: Langzam Eran , Isakov Eli , Mizrahi Joseph 
Published: November 2006

AbstractBackgroundHybrid muscle activation is a modality used for muscle force enhancement, in which muscle contraction is generated from two different excitation sources: volitional and external, by means of electrical stimulation (ES). Under hybrid activation, the overall EMG signal is the combination of the volitional and ES-induced components. In this study, we developed a computational scheme to extract the volitional EMG envelope from the overall dynamic EMG signal, to serve as an input signal for control purposes, and for evaluation of muscle forces.MethodsA "synthetic" database was created fromin-vivoexperiments on the Tibialis Anterior of the right foot to emulate hybrid EMG signals, including the volitional and induced components. The database was used to evaluate the results obtained from six signal processing schemes, including seven different modules for filtration, rectification and ES component removal. The schemes differed from each other by their module combinations, as follows: blocking window only, comb filter only, blocking window and comb filter, blocking window and peak envelope, comb filter and peak envelope and, finally, blocking window, comb filter and peak envelope.Results and conclusionThe results showed that the scheme including all the modules led to an excellent approximation of the volitional EMG envelope, as extracted from the hybrid signal, and underlined the importance of the artifact blocking window module in the process.The results of this work have direct implications on the development of hybrid muscle activation rehabilitation systems for the enhancement of weakened muscles.
Clinical features and hormonal profiles of cloprostenol-induced early abortions in heifers monitored by ultrasonography
Authors: Lobago Fikre , Gustafsson Hans , Bekana Merga , Beckers Jean-François , Kindahl Hans 
Published: November 2006

Abstract

Background
The present study describes the clinical features and plasma profiles of bovine pregnancy-associated glycoprotein 1 (bPAG1), the main metabolite of prostaglandin F2α (PG metabolite) and progesterone (P4) in heifers in which early abortions were induced.

Methods
Early abortions were induced in four heifers with cloprostenol and monitored by ultrasonography. Blood samples were collected and the plasma were analyzed for bPAG 1, P4 and PG metabolite.

Results
The foetal heartbeat rates varied from 170–186 beats per minute for all foetuses up to the date of cloprostenol treatment. Foetal death was confirmed within two days after cloprostenol treatment. Prior to cloprostenol injection, blood plasma concentrations of bPAG1, PG metabolite and P4 varied from 8.4 – 40.0 ng/mL, 158 – 275 pmol/L and 20.7 – 46.9 nmol/L, respectively. After the foetus expelled, the plasma level of bPAG1 began to decrease but the decrease was small and gradual. The estimated half-life of bPAG1 was 1.8 – 6.6 days. The plasma level of the PG metabolite started to have short lasting peaks (above 300 pmol/L) within three hours after cloprostenol treatment. The plasma concentrations of P4 dropped sharply to less than 4 nmol/L after 24 hours of cloprostenol injection.

Conclusion
The current findings indicated that after early closprostenol-induced foetal death, the plasma concentration of bPAG1 decreased gradually and showed a tendency of variation with the stages of pregnancy.
Coregulator Exchange and Sphingosine-Sensitive Cooperativity of Steroidogenic Factor-1, General Control Nonderepressed 5, p54, and p160 Coactivators Regulate Cyclic Adenosine 3′,5′-Monophosphate-Dependent Cytochrome P450c17 Transcription Rate
Authors: Dammer Eric B. , Leon Adam , Sewer Marion B. 
Published: November 2006

AbstractTranscription of the cytochrome P450 17 (CYP17) gene is regulated by cAMP-dependent binding of steroidogenic factor-1 (SF-1) to its promoter in the adrenal cortex. Using temporal chromatin immunoprecipitation and mammalian two-hybrid experiments, we establish the reciprocal presence of coactivators [general control nonderepressed (GCN5), cAMP response element-binding protein-binding protein, p300, p300/cAMP response element-binding protein-binding protein CBP associated factor, p160s, polypyrimidine tract associated splicing factor, and p54nrb], corepressors (class I histone deacetylases, receptor interacting protein, nuclear receptor corepressor, and Sin3A), and SWI/SNF (human homolog of yeast mating type switching/sucrose nonfermenting) and imitation SWI chromatin remodeling ATPases on the CYP17 promoter during transcription cycles in the H295R adrenocortical cell line. A ternary GCN5/SRC-1/SF-1 complex forms on the CYP17 promoter with cAMP-dependence within 30 min of cAMP stimulation, and corresponds with SWI/SNF chromatin remodeling. This complex is sensitive to the SF-1 antagonist sphingosine and results in decreased transcription of CYP17. GCN5 acetyltransferase activity and carboxy terminus binding proteins alternatively mediate disassembly of the complex. This work establishes the temporal order of cAMP-induced events on the promoter of a key steroidogenic gene during SF-1-mediated transcription.
Dynamic Compression Regulates the Expression and Synthesis of Chondrocyte-Specific Matrix Molecules in Bone Marrow Stromal Cells
Authors: Mouw Janna K. , Connelly John T. , Wilson Christopher G. , Michael Kristin E. , Levenston Marc E. 
Published: November 2006

Abstract
The overall objective of the present study was to investigate the mechanotransduction of bovine bone marrow stromal cells (BMSCs) through the interactions between transforming growth factor β1 (TGF-β1), dexamethasone, and dynamic compressive loading. Overall, the addition of TGF-β1 increased cell viability, extracellular matrix (ECM) gene expression, matrix synthesis, and sulfated glycosaminoglycan content over basal construct medium. The addition of dexamethasone further enhanced extracellular matrix gene expression and protein synthesis. There was little stimulation of ECM gene expression or matrix synthesis in any medium group by mechanical loading introduced on day 8. In contrast, there was significant stimulation of ECM gene expression and matrix synthesis in chondrogenic media by dynamic loading introduced on day 16. The level of stimulation was also dependent on the medium supplements, with the samples treated with basal medium being the least responsive and the samples treated with TGF-β1 and dexamethasone being the most responsive at day 16. Both collagen I and collagen II gene expressions were more responsive to dynamic loading than aggrecan gene expression. Dynamic compression upregulated Smad2/3 phosphorylation in samples treated with basal and TGF-β1 media. These findings suggest that interactions between mechanical stimuli and TGF-β signaling may be an important mechanotransduction pathway for BMSCs, and they indicate that mechanosensitivity may vary during the process of chondrogenesis.
Concise Review: Stem Cells, Myocardial Regeneration, and Methodological Artifacts
Authors: Anversa Piero , Leri Annarosa , Rota Marcello , Hosoda Toru , Bearzi Claudia , Urbanek Konrad , Kajstura Jan , Bolli Roberto 
Published: November 2006

Abstract
This review discusses the current controversy about the role that endogenous and exogenous progenitor cells have in cardiac homeostasis and myocardial regeneration following injury. Although great enthusiasm was created by the possibility of reconstituting the damaged heart, the opponents of this new concept of cardiac biology have interpreted most of the findings supporting this possibility as the product of technical artifacts. This article challenges this established, static view of cardiac growth and favors the notion that the mammalian heart has the inherent ability to replace its cardiomyocytes through the activation of a pool of resident primitive cells or the administration of hematopoietic stem cells.