Mineral resource of the month: talc

USGS Publications Warehouse

Virta, Robert; Van Gosen, Brad

2007-01-01

When most people think of talc, they probably think of talcum and baby powder. However, these uses of talc are quite minor compared to its wide variety of applications in manufacturing. The leading use of talc is in the production of ceramics, where it acts as a source of magnesium oxide, serves as a flux to reduce firing temperatures and improves thermal shock characteristics of the final product.

Gel Electrolytes with Polyamidopyridine Dendron Modified Talc for Dye-Sensitized Solar Cells.

PubMed

Santana Andrade, Marcos A; Tiihonen, Armi; Miettunen, Kati; Lund, Peter; Nogueira, Ana F; Pastore, Heloise O

2017-06-21

Organic-inorganic hybrid layered materials are proposed as additives in a quasi-solid gel electrolyte for dye-sensitized solar cells. Talcs could provide a low-cost and environmentally friendly, as well as abundant, option as gelators. Here, talcs were prepared by functionalizing an organotalc with three polyamidopyridine dendron generations, PAMPy-talc-Gn (n = 1, 2 and 3). PAMPy dendrons grow parallel to the lamellae plane and form an organized structure by intermolecular interactions. In addition, polyiodide-dendron charge-transfer complexes were prepared onto the organotalc by adsorption of iodine. In this work, the effect of the dendron generation of PAMPy-talc and the influence of polyiodide intercalation on solar cell performance and stability were investigated. The best results were reached with the use of lowest-generation PAMPy-talc (η = 4.5 ± 0.3%, V OC = 710 ± 19 mV, J sc = 10.4 ± 0.9 mA cm -2 , and FF = 61 ± 2%): 15% higher efficiency compared to similar liquid devices. While some previously studied talcs illustrate very strong absorption of the iodide from the electrolyte, in the case of PAMPy-talc such interfering effects were absent: In a 1000 h light soaking test, the PAMPy-talc cells both with and without polyiodide intercalation demonstrated stable performances. Furthermore, the color analysis of the electrolyte indicated that the color of the electrolyte remained stable after an initial period of stabilization, which is a good indication of the compound being stable and not absorbing charge carriers from the electrolyte. The performance and stability results indicate that PAMPy-talc has potential as a gelling method for electrolytes for dye solar cells.

Mineral Resource of the Month: Talc

USGS Publications Warehouse

Virta, Robert L.; Van Gosen, Bradley S.

2014-01-01

When people think of talc, they often think of talcum and baby powder. However, these uses of talc are minor compared to its use in industrial manufacturing. The leading use of talc in the United States is in the production of ceramics, where it is a source of magnesium oxide, serves as a flux to reduce firing temperatures, and improves thermal shock characteristics of the final product. Worldwide, the major use of talc is as a paper constituent, where it fills the interstices between cellulose paper fibers, reduces paper transparency, improves ink receptivity, and absorbs undesirable tree sap residues that can generate blemishes in the paper.

The Genesis of tectonically and hydrothermally controlled industry mineral deposits: A geochemical and structural study

NASA Astrophysics Data System (ADS)

Wölfler, Anke; Prochaska, Walter; Henjes-Kunst, Friedhelm; Fritz, Harald

2010-05-01

The study aims to investigate the role of hydrothermal fluids in the formation of talc and magnesite deposits. These deposits occur in manifold geological and tectonical settings such as stockworks and veins within ultramafite hostrocks and monomineralic lenses within marine platform sediments. Along shear zones talc mineralizations may occur as a result of tectonical and hydrothermal activity. To understand the role of the fluids for the genesis of the mineralization, deposits in different geological and tectonical settings are investigated: Talc mineralization within in magnesite in low-grade palaeozoic nappe complexes (Gemerska Poloma, Slovakia): The magnesite body lies within the Gemer unit of the Inner Carpathians consisting of Middle Triassic metacarbonates and Upper Triassic pelagic limestones and radiolarites. The talc mineralization is bound to crosscutting veins. Two metamorphic events can be distinguished, one during Variscan orogeny and one related to the Alpine orogeny leading to the formation of talc along faults in an Mg carbonate body (Radvanec et al, 2004).The origin of the fluids as well as the tectonic events leading to the mineralization is still widely unknown. Talc mineralization in shearzones within Palaeozoic meta sedimentary rocks (Sa Matta, Sardinia): Variscan granitoids intruded Palaeozoic meta sedimentary rocks and were overprinted be NE striking tectonic structures that host talc mineralizations. The origin of Mg and fluids leading to the mineralization is still not answered satisfactorily (Grillo and Prochaska, 2007) and thus a tectonic model for the genesis of the talc deposit is missing. Talc mineralization within UHP pre-Alpine continental crust (Val Chisone, Italy): The talc deposit forms part of the Dora-Maira Massif. Geologicaly the massif derived from a Variscan basement that includes post-Variscan intrusions. The talc mineralization occurs as a sheetlike, conformable body. A possible tectonic emplacement of talc along shear surfaces was proposed by Sandrone & Zucchetti, 1988. Magnesite and talc bearing shearzones in ultramafic hostrocks (Lahnaslampi & Horsmanaho, Finland): Both deposits are situated in the Proterozoic schist belt where the talc-magnesite rocks at Lahnaslampi are associated with minor serpentine breccias. The steatitization took place in two different stages: During prograde metamorphism with H2O-dominated solutions and at declining temperature and pressure in the presence of CO2-bearing fluids that resulted in the main steatitization along tectonic structures. A combined geological, petrological and geochronological is chosen to resolve mechanism of mineralisation within the different tectonic setting. Different phases of mineral formation are first distinguished by pertrological and structural field work and then dated by radiometric techniques. Fluid species and chemical environment during mineralisation is resolved by geochemical techniques and stable isotope studies. References Grillo, S., Prochaska, W. (2007): Fluid Chemistry and Stable Isotope Evidence of Shearzone related Talc and Chlorite Mineralizations in Central Sardinia-Italy, In: Conference Abstracts SGA-Meeting. Radvanec, M., Koděra, P., Prochaska, W. (2004): Mg replacement of the Gemerska Poloma talk-magnesite deposit, Western Carpathians, Slovakia. Acta Petrologica Sinica, 20, 773-790. Sandrone, Zucchetti (1988): Geology of the Italian high-quality cosmetic talc from the Pinerolo district (Western Alps). Zuffar' Days - Symposium held in Cagliari, 10-15

Quantitative elemental analysis of an industrial mineral talc, using accelerator-based analytical technique

NASA Astrophysics Data System (ADS)

Olabanji, S. O.; Ige, A. O.; Mazzoli, C.; Ceccato, D.; Ajayi, E. O. B.; De Poli, M.; Moschini, G.

2005-10-01

Accelerator-based technique of PIXE was employed for the determination of the elemental concentration of an industrial mineral, talc. Talc is a very versatile mineral in industries with several applications. Due to this, there is a need to know its constituents to ensure that the workers are not exposed to health risks. Besides, microscopic tests on some talc samples in Nigeria confirm that they fall within the BP British Pharmacopoeia standard for tablet formation. However, for these samples to become a local source of raw material for pharmaceutical grade talc, the precise elemental compositions should be established which is the focus of this work. Proton beam produced by the 2.5 MV AN 2000 Van de Graaff accelerator at INFN, LNL, Legnaro, Padova, Italy was used for the PIXE measurements. The results which show the concentration of different elements in the talc samples, their health implications and metabolic roles are presented and discussed.

Talc friction in the temperature range 25°–400 °C: relevance for fault-zone weakening

USGS Publications Warehouse

Moore, Diane E.; Lockner, David A.

2008-01-01

Talc has a temperature–pressure range of stability that extends from surficial to eclogite-facies conditions, making it of potential significance in a variety of faulting environments. Talc has been identified in exhumed subduction zone thrusts, in fault gouge collected from oceanic transform and detachment faults associated with rift systems, and recently in serpentinite from the central creeping section of the San Andreas fault. Typically, talc crystallized in the active fault zones as a result of the reaction of ultramafic rocks with silica-saturated hydrothermal fluids. This mode of formation of talc is a prime example of a fault-zone weakening process. Because of its velocity-strengthening behavior, talc may play a role in stabilizing slip at depth in subduction zones and in the creeping faults of central and northern California that are associated with ophiolitic rocks.

Genesis of giant Early Proterozoic magnesite and related talc deposits in the Mafeng area, Liaoning Province, NE China

NASA Astrophysics Data System (ADS)

Misch, David; Pluch, Hannes; Mali, Heinrich; Ebner, Fritz; Huang, Hui

2018-07-01

This study aims to understand the origin of giant magnesite and talc deposits in the Liaohe Group (Liaoning Province, NE China). Magnesite stromatolites and the composition of fluid inclusions suggest that magnesite or high-Mg calcite precipitated directly from strongly restricted seawater pools with meteoric influx. A primary evaporitic origin is also indicated for parts of the investigated dolomites by comparably heavy δ18O values. Later, intense metasomatic activity led to the formation of a magnesite/dolomite succession with irregular contacts and a lighter isotopic signature of oxygen. A slight shift in δ18O to more positive values was observed for talc-hosting magnesite, which can be explained by the incorporation of isotopically light oxygen into talc. This highlights that the hydrothermal processes that led to talc formation influenced the hosting carbonates as well, which is also documented by a tendency to smaller crystal sizes, a higher whiteness and lower trace element concentrations in samples from locations nearby large talc bodies. Although δ13C is suggested to be less sensitive to hydrothermal activity, comparably light δ13C values were determined for magnesite sinters, as well as for remobilized magnesites. In general, the δ13C signature of the investigated magnesites is lighter than expected for Proterozoic carbonates. A single-stage generation of the giant talc deposit in the study area is suggested based on elemental and isotopic data. Later deformation led to a (iso-chemical) re-location of talc at least once. During this process, irregularly distributed, cloudy/massive talc bodies acted as weak zones and were incorporated into shear bands up to several meters in thickness, which form the actually present, structurally controlled deposit. The original ore type is preserved only in areas with minor deformation. Lamprophyre dykes prove Jurassic volcanism and are clearly younger than the main phase of talc generation. A younger (post-Jurassic?), intense tectonic event is indicated by strongly tectonized dyke material that is re-worked into strike-slip faults and shows siliceous contact zones to the surrounding magnesite. These faults occasionally cross-cut the older, deposit-forming talc shear bands, indicating that the event that led to the deformation of lamprophyre dykes was younger than the main phase of talc re-location. However, this younger event did not lead to a second phase of major talc generation or affect the quality of the initial deposit to a large extent.

Analysis and Characterization of High-Purity Talc for Use in Propellants; Determination of Talc in Propellants

DTIC Science & Technology

1975-12-01

is determined by combustion in an induction furnace with iron as a flux. The methods for moisture, loss in ignition, water-soluble matter, acid... determination of talc in nitro- cellulose-base propellants. The first method (which is the method recom- mended for the usual nitrocellulose -base...In the present report an improved scheme is proposed for the analysis of talc. The silica and magnesium oxide are determined by fusion with sodium

Listwaenite in the Sartohay ophiolitic mélange (Xinjiang, China): A genetic model based on petrology, U-Pb chronology and trace element geochemistry

NASA Astrophysics Data System (ADS)

Qiu, Tian; Zhu, Yongfeng

2018-03-01

Listwaenite lenses in the Sartohay ophiolitic mélange (Xinjiang, China) were formed via reactions between serpentinite and metasomatic fluids. First, serpentinite changed into talc schist via the reaction of serpentine + CO2 → talc + magnesite + H2O. Second, talc schist changed into listwaenite via the reaction of talc + CO2 → magnesite + quartz + H2O. Magnetite was progressively destroyed during transformation from serpentinite to talc schist, and completely consumed in listwaenite. Zircon crystals 30-100 μm long, disseminating in talc schist, undeformed listwaenite and mylonitized listwaenite, coexist with talc, quartz and magnesite, while micron-sized zircon grains (<5 μm in length) occur along the shearing foliation in the weakly deformed listwaenite and mylonitized listwaenite. We postulate that these micron-sized zircon crystals may have grown in-situ from medium-temperature hydrothermal fluids. Concentrations of most trace elements including high field strength elements (HFSE) increase from the undeformed, through the weakly deformed, to the mylonitized listwaenite, showing a positive correlation with the degrees of deformation and proportions of micron-size zircon, apatite, rutile and monazite. The large zircon crystals recovered from talc schist, undeformed listwaenite and mylonitized listwaenite yield similar weighted mean U-Pb ages (302.9 ± 6.8 Ma, 299.7 ± 5.5 Ma and 296.5 ± 3.5 Ma), and are thought to represent the age of formation of the talc schist and listwaenite. These ages are indistinguishable within errors and suggest a rapid transformation from talc schist to listwaenite. Some zircon rims in samples of the undeformed listwaenite and mylonitized listwaenite give much younger apparent U-Pb ages (280-277 Ma), which could be interpreted as a recrystallization age reflecting late-stage shearing in the Sartohay ophiolitic mélange.

Effect of Hybrid Talc-Basalt Fillers in the Shell Layer on Thermal and Mechanical Performance of Co-Extruded Wood Plastic Composites

PubMed Central

Huang, Runzhou; Mei, Changtong; Xu, Xinwu; Kärki, Timo; Lee, Sunyoung; Wu, Qinglin

2015-01-01

Hybrid basalt fiber (BF) and Talc filled high density polyethylene (HDPE) and co-extruded wood-plastic composites (WPCs) with different BF/Talc/HDPE composition levels in the shell were prepared and their mechanical, morphological and thermal properties were characterized. Incorporating BFs into the HDPE-Talc composite substantially enhanced the thermal expansion property, flexural, tensile and dynamic modulus without causing a significant decrease in the tensile and impact strength of the composites. Strain energy estimation suggested positive and better interfacial interactions of HDPE with BFs than that with talc. The co-extruded structure design improved the mechanical properties of WPC due to the protective shell layer. The composite flexural and impact strength properties increased, and the thermal expansion decreased as BF content increased in the hybrid BF/Talc filled shells. The cone calorimetry data demonstrated that flame resistance of co-extruded WPCs was improved with the use of combined fillers in the shell layer, especially with increased loading of BFs. The combined shell filler system with BFs and Talc could offer a balance between cost and performance for co-extruded WPCs. PMID:28793726

Effect of Hybrid Talc-Basalt Fillers in the Shell Layer on Thermal and Mechanical Performance of Co-Extruded Wood Plastic Composites.

PubMed

Huang, Runzhou; Mei, Changtong; Xu, Xinwu; Kärki, Timo; Lee, Sunyoung; Wu, Qinglin

2015-12-08

Hybrid basalt fiber (BF) and Talc filled high density polyethylene (HDPE) and co-extruded wood-plastic composites (WPCs) with different BF/Talc/HDPE composition levels in the shell were prepared and their mechanical, morphological and thermal properties were characterized. Incorporating BFs into the HDPE-Talc composite substantially enhanced the thermal expansion property, flexural, tensile and dynamic modulus without causing a significant decrease in the tensile and impact strength of the composites. Strain energy estimation suggested positive and better interfacial interactions of HDPE with BFs than that with talc. The co-extruded structure design improved the mechanical properties of WPC due to the protective shell layer. The composite flexural and impact strength properties increased, and the thermal expansion decreased as BF content increased in the hybrid BF/Talc filled shells. The cone calorimetry data demonstrated that flame resistance of co-extruded WPCs was improved with the use of combined fillers in the shell layer, especially with increased loading of BFs. The combined shell filler system with BFs and Talc could offer a balance between cost and performance for co-extruded WPCs.

[Talc-induced pulmonary granulomas in drug addicts].

PubMed

Latartseva, L N; Kryvenko, O N

2013-01-01

Among the diseases accompanied by granuloma formation in the lung, there is so-called granulomatosis developing in injection drug users who have been long injecting suspensions of oral medications containing talc and other water insoluble fillers. 102 deaths of chronic intravenous drug users were examined; 12 of whom showed pulmonary talc-induced granulomatosis. Their morphology was studied using polarized light microscopy. The main mechanisms of thanatogenesis in lethal cases within the first hours after intravenous injection of talc-containing oral medication suspensions are explained.

Dehydration kinetics and thermochemistry of selected hydrous phases, and simulated gas release pattern in carbonaceous chondrites

NASA Technical Reports Server (NTRS)

Bose, Kunal; Ganguly, J.

1992-01-01

As part of our continued program of study on the volatile bearing phases and volatile resource potential of carbonaceous chondrite, results of our experimental studies on the dehydration kinetics of talc as a function of temperature and grain size (50 to 0.5 microns), equilibrium dehydration boundary of talc to 40 kbars, calorimetric study of enthalpy of formation of both natural and synthetic talc as a function of grain size, and preliminary results on the dehydration kinetics of epsomite are reported. In addition, theoretical calculations on the gas release pattern of Murchison meteorite, which is a C2(CM) carbonaceous chondrite, were performed. The kinetic study of talc leads to a dehydration rate constant for 40-50 microns size fraction of k = (3.23 x 10(exp 4))exp(-Q/RT)/min with the activation energy Q = 376 (plus or minus 20) kJ/mole. The dehydration rate was found to increase somewhat with decreasing grain size. The enthalpy of formation of talc from elements was measured to be -5896(10) kJ/mol. There was no measurable effect of grain size on the enthalpy beyond the limits of precision of the calorimetric studies. Also the calorimetric enthalpy of both synthetic and natural talc was found to be essentially the same, within the precision of measurements, although the natural talc had a slightly larger field of stability in our phase equilibrium studies. The high pressure experimental data the dehydration equilibrium of talc (talc = enstatite + coesite + H2O) is in strong disagreement with that calculated from the available thermochemical data, which were constrained to fit the low pressure experimental results. The calculated gas release pattern of Murchison meteorite were in reasonable agreement with that determined by stepwise heating in a gas chromatograph.

Malignant pleural effusions and the role of talc poudrage and talc slurry: a systematic review and meta-analysis

PubMed Central

Mummadi, Srinivas; Kumbam, Anusha; Hahn, Peter Y.

2015-01-01

Background: Malignant Pleural Effusion (MPE) is common with advanced malignancy. Palliative care with minimal adverse events is the cornerstone of management. Although talc pleurodesis plays an important role in treatment, the best modality of talc application remains controversial.   Objective: To compare rates of successful pleurodesis, rates of respiratory and non-respiratory complications between thoracoscopic talc insufflation/poudrage (TTI) and talc slurry (TS).  Data sources and study selection: MEDLINE (PubMed, OVID),  EBM Reviews (Cochrane database of Systematic Reviews, ACP Journal Club, DARE, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register, Health Technology Assessment and NHS Economic Evaluation Database), EMBASE and Scopus. Randomized controlled trials published between 01/01/1980 - 10/1/2014 and comparing the two strategies were selected.  Results: Twenty-eight potential studies were identified of which 24 studies were further excluded, leaving four studies. No statistically significant difference in the probability of successful pleurodesis was observed between TS and TTI groups (RR 1.06; 95 % CI 0.99-1.14; Q statistic, 4.84). There was a higher risk of post procedural respiratory complications in the TTI group compared to the TS group (RR 1.91, 95% CI= 1.24-2.93, Q statistic 3.15). No statistically significant difference in the incidence of non-respiratory complications between the TTI group and the TS group was observed (RR 0.88, 95% CI= 0.72-1.07, Q statistic 4.61). Conclusions: There is no difference in success rates of pleurodesis based on patient centered outcomes between talc poudrage and talc slurry treatments.  Respiratory complications are more common with talc poudrage via thoracoscopy. PMID:25878773

Preparation and Surface Property of Fluoroalkyl End-Capped Vinyltrimethoxysilane Oligomer/Talc Composite-Encapsulated Organic Compounds: Application for the Separation of Oil and Water.

PubMed

Oikawa, Yuri; Saito, Tomoya; Yamada, Satoshi; Sugiya, Masashi; Sawada, Hideo

2015-07-01

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R(F)-(CH2-CHSi(OMe)3)n-R(F); n = 2, 3; R(F) = CF(CF3)OC3F7 (R(F)-VM oligomer)] can undergo the sol-gel reaction in the presence of talc particles under alkaline conditions at room temperature to provide the corresponding fluorinated oligomeric silica/talc nanocomposites (RF-VM-SiO2/Talc). A variety of guest molecules such as 2-hydroxy-4-methoxybenzophenone (HMB), bisphenol A (BPA), bisphenol AF, 3-(hydroxysilyl)-1-propanesulfonic acid (THSP), and perfluoro-2-methyl-3-oxahexanoic acid (R(F)-COOH) are effectively encapsulated into the R(F)-VM-SiO2/Talc composite cores to afford the corresponding fluorinated nanocomposites-encapsulated these guest molecules. The R(F)-VM-SiO2/Talc composites encapsulated low molecular weight aromatic compounds such as HMB and BPA can exhibit a superoleophilic-superhydrophobic characteristic on the surfaces; however, the R(F)-VM-SiO2/Talc composite-encapsulated THSP and R(F)-COOH exhibit a superoleophobic-superhydrophilic characteristic on the modified surfaces. In these nanocomposites, the R(F)-VM-SiO2/Talc/THSP composites are applicable to the surface modification of polyester fabric, and the modified polyester fabric possessing a superoleophobic-superhydrophilic characteristic on the surface can be used for the membrane for oil (dodecane)/water separation. In addition, the R(F)-VM-SiO2/Talc composites-encapsulated micrometer-size controlled cross-linked polystyrene particles can be also prepared under similar conditions, and the obtained composite white-colored particle powders are applied to the packing material for the column chromatography to separate water-in-oil (W/O) emulsion.

Malignant mesothelioma incidence among talc miners and millers in New York State.

PubMed

Finkelstein, Murray M

2012-10-01

There is controversy about the potential for dust from the talc mines and mills of New York State to cause mesothelioma. Honda et al. published a study of mortality among New York talc workers and concluded that it was unlikely that the two deaths from mesothelioma were caused by talc ore dust. However, fibers of tremolite and anthophyllite have been found in the lungs of talc workers and Hull concluded that "New York talc exposure is associated with mesothelioma, and deserves further public health attention." Data concerning additional cases of mesothelioma in the cohort have been posted by NIOSH. I used information from the NIOSH website and the Honda report to analyze the incidence of mesothelioma during the years 1990-2007. There were at least five new cases of mesothelioma in the cohort and mesothelioma incidence rates were at least five (1.6-11.7) times the rate in the general population (P < 0.01). I conclude that: (1) mesothelioma has been diagnosed among members of the cohort at a rate in excess of that in the general population; (2) fibers of tremolite and anthophyllite have been detected in dust and the lungs of talc workers; and (3) these fibers are known causes of mesothelioma. It is prudent, on the balance of probabilities, to conclude that dusts from New York State talc ores are capable of causing mesothelioma in exposed individuals. Copyright © 2012 Wiley Periodicals, Inc.

Immunosuppression induced by talc granulomatosis in the rat.

PubMed Central

Radić, I; Vucak, I; Milosević, J; Marusić, A; Vukicević, S; Marusić, M

1988-01-01

Granulomatosis caused by four subcutaneous talc powder-suspension injections induced strong immunosuppression in rats. The disturbance included reduction of mononuclear white blood cell count in the peripheral blood, atrophy of the thymic cortex, spleen enlargement with predominance of red over the white pulp, increase in the number of lymph node germinal centres and a significant delay of the first-set and second-set allograft rejection. Neither phagocytic function of reticuloendothelial system nor erythrocyte count and humoral immune response were found to be altered. Indomethacin suppression of prostaglandin production did not normalize the allograft rejection dynamics. In contrast, splenectomy completely abolished the immunosuppressive effects of granulomatosis. In splenectomized, talc-treated animals WBC counts were not altered and the rejection of allografts was not delayed. Suppression of immune response to alloantigens was transferred to normal and splenectomized recipients by both serum and spleen cells of talc-injected animals. Also, in a cell mixture-transfer experiment, spleen cells from talc-granulomatosis-bearing donors suppressed the immune response induced by lymph node cells from immune donors in T cell-deficient rats. The inability of serum from splenectomized talc-injected rats to transfer the suppression suggested the crucial role of the spleen in the mechanisms leading to suppression in rats bearing talc-granulomatosis. PMID:3052948

Ab initio elastic properties of talc from 0 to 12 GPa: Interpretation of seismic velocities at mantle pressures and prediction of auxetic behaviour at low pressure

NASA Astrophysics Data System (ADS)

Mainprice, David; Le Page, Yvon; Rodgers, John; Jouanna, Paul

2008-10-01

Talc is a hydrous magnesium rich layered silicate that is widely disseminated in the Earth from the seafloor to over 100 km depth, in ultra-high pressure metamorphism of oceanic crust. In this paper we determine the single crystal elastic constants at pressures from 0 to 12 GPa of talc triclinic ( C 1¯) and monoclinic (C2/ c) polytypes using ab initio methods. We find that talc has an extraordinarily high elastic anisotropy at zero pressure that reduces with increasing pressure. The exceptional anisotropy is complemented by a negative Poisson's ratio for many directions in crystal space. Calculations show that talc is not only one of very few common minerals to exhibit auxetic behaviour, but the magnitude of this effect may be the largest reported so far for a mineral. The compression (Vp) and shear (Vs) wave velocity anisotropy is 80% and 85% for the triclinic polytype. At pressures where talc is known be stable in the Earth (up to 5 GPa) the Vp and Vs anisotropy is reduced to about 40% for both velocities, which is still a very high value. Vp is slow parallel to the c-axis and fast perpendicular to it. This remains unchanged with increasing pressure and is observed in both polytypes. The shear wave splitting (difference between fast and slow S-wave velocities) at low pressure has high values in the plane normal to the c-axis, with a maximum near the a*-axis in the triclinic and the b-axis in the monoclinic polytype. The c-axis is the direction of minimum splitting. The pattern of shear wave splitting does not change significantly with pressure. The volume fraction of talc varies between 11 and 41% for hydrated mantle rocks, but the lack of data on the crystallographic preferred orientation (CPO) precludes a detailed analysis of the impact of talc on seismic anisotropy in subduction zones. However, it is highly likely that CPO can easily develop in zones of deformation due to the platy habit of talc crystals. For random aggregates of talc, the isotropic Vp, Vs and Vp/Vs ratio have significantly lower values than those of antigorite and may explain low-velocity regions in the mantle wedge. Vp/Vs ratios are more complex in anisotropic media because there are fast and slow S-waves, resulting in Vp/Vs1 and Vp/Vs2 ratios for every propagation direction, making interpretation difficult in deformed polycrystalline talc with a CPO. Talc on the subduction plate boundary can strongly influence guided wave velocity as CPO would develop in this region of intense shearing. The very low coefficient of friction (< 0.1) of talc above 100 °C could also explain silent earthquakes at shallow depths ( ca 30 km) along the subduction plate boundaries, frequently responsible for tsunami.

OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC MINE LOOKING EAST. THE OPENING TO THE TALC MINE IS IN THE DARK AREA AT CENTER LEFT EDGE. WARM SPRINGS CAMP IS OUT OF FRAME TO THE RIGHT. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

Does pleurodesis for pleural effusions give bright ideas about the agents for hydrocele sclerotherapy?

PubMed

Yilmaz, U; Ekmekçioğlu, O; Tatlişen, A; Demirci, D

2000-01-01

Evaluation of the effectiveness of rifampicin and some agents used in the pleurodesis of pleural effusions, such as autologous blood and purified mineral talc. A total of 56 hydroceles were treated by sclerotherapy, in a random fashion, using purified mineral talc, rifampicin and autologous blood as sclerosant agents. The control group of patients were handled with aspiration only. The cohort of patients in the blood group had a success rate comparable to the control group (p > 0.05). the rifampicin group did better than both control and blood groups (p < 0.05) but not better than the talc group (p < 0.01). Success rate was highest in the talc group of patients who needed no re-sclerotherapy procedures. Purified mineral talc was shown to be potentially the best sclerosant for the sclerotherapy of hydroceles and epididymal cysts.

Pulmonary talc granulomatosis in a cocaine sniffer.

PubMed

Oubeid, M; Bickel, J T; Ingram, E A; Scott, G C

1990-07-01

The development of pulmonary granulomatosis following intravenous injection of medications intended for oral use has been well described previously. Talc is the most commonly implicated agent. We present a case of talc granulomatosis which developed in a patient following cocaine sniffing and suggest that this may be the cause of development of granulomata in drug addicts who deny any history of intravenous drug abuse.

Interstitial pulmonary fibrosis and progressive massive fibrosis related to smoking methamphetamine with talc as filler.

PubMed

Baylor, Peter A; Sobenes, Juan R; Vallyathan, Val

2013-05-01

We present a case of interstitial pulmonary fibrosis accompanied by radiographic evidence of progressive massive fibrosis in a patient who had a 15-20 year history of almost daily recreational inhalation of methamphetamine. Mineralogical analysis confirmed the presence of talc on biopsy of the area of progressive massive fibrosis. The coexistence of interstitial pulmonary fibrosis and progressive massive fibrosis suggests that prolonged recreational inhalation of methamphetamine that has been "cut" with talc can result in sufficient amount of talc being inhaled to result in interstitial pulmonary fibrosis and progressive massive fibrosis in the absence of other causes.

Effect of an indwelling pleural catheter vs chest tube and talc pleurodesis for relieving dyspnea in patients with malignant pleural effusion: the TIME2 randomized controlled trial.

PubMed

Davies, Helen E; Mishra, Eleanor K; Kahan, Brennan C; Wrightson, John M; Stanton, Andrew E; Guhan, Anur; Davies, Christopher W H; Grayez, Jamal; Harrison, Richard; Prasad, Anjani; Crosthwaite, Nicola; Lee, Y C Gary; Davies, Robert J O; Miller, Robert F; Rahman, Najib M

2012-06-13

Malignant pleural effusion causes disabling dyspnea in patients with a short life expectancy. Palliation is achieved by fluid drainage, but the most effective first-line method has not been determined. To determine whether indwelling pleural catheters (IPCs) are more effective than chest tube and talc slurry pleurodesis (talc) at relieving dyspnea. Unblinded randomized controlled trial (Second Therapeutic Intervention in Malignant Effusion Trial [TIME2]) comparing IPC and talc (1:1) for which 106 patients with malignant pleural effusion who had not previously undergone pleurodesis were recruited from 143 patients who were treated at 7 UK hospitals. Patients were screened from April 2007-February 2011 and were followed up for a year. Indwelling pleural catheters were inserted on an outpatient basis, followed by initial large volume drainage, education, and subsequent home drainage. The talc group were admitted for chest tube insertion and talc for slurry pleurodesis. Patients completed daily 100-mm line visual analog scale (VAS) of dyspnea over 42 days after undergoing the intervention (0 mm represents no dyspnea and 100 mm represents maximum dyspnea; 10 mm represents minimum clinically significant difference). Mean difference was analyzed using a mixed-effects linear regression model adjusted for minimization variables. Dyspnea improved in both groups, with no significant difference in the first 42 days with a mean VAS dyspnea score of 24.7 in the IPC group (95% CI, 19.3-30.1 mm) and 24.4 mm (95% CI, 19.4-29.4 mm) in the talc group, with a difference of 0.16 mm (95% CI, −6.82 to 7.15; P = .96). There was a statistically significant improvement in dyspnea in the IPC group at 6 months, with a mean difference in VAS score between the IPC group and the talc group of −14.0 mm (95% CI, −25.2 to −2.8 mm; P = .01). Length of initial hospitalization was significantly shorter in the IPC group with a median of 0 days (interquartile range [IQR], 0-1 day) and 4 days (IQR, 2-6 days) for the talc group, with a difference of −3.5 days (95% CI, −4.8 to −1.5 days; P < .001). There was no significant difference in quality of life. Twelve patients (22%) in the talc group required further pleural procedures compared with 3 (6%) in the IPC group (odds ratio [OR], 0.21; 95% CI, 0.04-0.86; P = .03). Twenty-one of the 52 patients in the catheter group experienced adverse events vs 7 of 54 in the talc group (OR, 4.70; 95% CI, 1.75-12.60; P = .002). Among patients with malignant pleural effusion and no previous pleurodesis, there was no significant difference between IPCs and talc pleurodesis at relieving patient-reported dyspnea. isrctn.org Identifier: ISRCTN87514420.

Comparison of side effects of oxytetracycline and talc pleurodesis: an experimental study.

PubMed

Gözübüyük, Alper; Ozpolat, Berkant; Ciçek, Ali Fuat; Caylak, Hasan; Yücel, Orhan; Kavaklı, Kuthan; Gürkök, Sedat; Genç, Onur

2010-12-13

Chemical pleurodesis is widely recommended in the treatment of refractory pleural effusion or pulmonary air leak of different etiologies. Although several agents have been used, many questions have remained unanswered about their toxicity. Talc is the most commonly used agent for the treatment, with rare, serious complications reported. Oxytetracycline pleurodesis in clinical practice has been described in a few studies, but literature reveals no experimental studies using this agent. We performed a prospective, randomized, observer-blinded, controlled study to evaluate the changes in lung histology and systemic response to pleurodesis with oxytetracycline and talc in acute and subacute phases in a rat model. Forty-two male albino Wistar rats were divided into three groups and 3 subgroups with 7 animals in each. Group 1 was given oxytetracycline, 35 mg/kg; Group 2 was given talc slurry, 60 mg/kg in 0.5 mL saline solution, and Group 3 was given only 0.5 mL saline intrapleurally. In subgroups "a" the nimls were sacrificed at the postoperative 72nd hour and, in subgroups "b", on the postoperative day 7. The surfaces were graded by microscopic examination. Oxytetracycline produced alveolar collapse, hemorrhage, edema, inflammation at the postoperative 72nd hour and hemorrhage on the postoperative day 7, while talc produced significant edema, inflammation, proliferation, fibrosis at the postoperative 72nd hour and hemorrhage, edema, inflammation, proliferation, and fibrosis on the postoperative day 7 (p < 0.0042). Talc produced significant edema compared to oxytetracycline on the postoperative day 7. On contralateral side, oxytetracycline and talc produced significant hemorrhage on the postoperative day 7 (p < 0.0042). Both agents were shown to produce pulmonary lesions. In acute phase, the pulmonary side effects of oxytetracycline were more pronounced, whereas the side effects of talc were prolonged to subacute phase. We propose that the occasional side effects in humans may be related to these changes as were observed in our rat model, and like talc, oxytetracycline must be used cautiously in patients with limited respiratory function.

Comparison of side effects of oxytetracycline and talc pleurodesis: an experimental study

PubMed Central

2010-01-01

Background Chemical pleurodesis is widely recommended in the treatment of refractory pleural effusion or pulmonary air leak of different etiologies. Although several agents have been used, many questions have remained unanswered about their toxicity. Talc is the most commonly used agent for the treatment, with rare, serious complications reported. Oxytetracycline pleurodesis in clinical practice has been described in a few studies, but literature reveals no experimental studies using this agent. We performed a prospective, randomized, observer-blinded, controlled study to evaluate the changes in lung histology and systemic response to pleurodesis with oxytetracycline and talc in acute and subacute phases in a rat model. Methods Forty-two male albino Wistar rats were divided into three groups and 3 subgroups with 7 animals in each. Group 1 was given oxytetracycline, 35 mg/kg; Group 2 was given talc slurry, 60 mg/kg in 0.5 mL saline solution, and Group 3 was given only 0.5 mL saline intrapleurally. In subgroups "a" the nimls were sacrificed at the postoperative 72nd hour and, in subgroups "b", on the postoperative day 7. The surfaces were graded by microscopic examination. Results Oxytetracycline produced alveolar collapse, hemorrhage, edema, inflammation at the postoperative 72nd hour and hemorrhage on the postoperative day 7, while talc produced significant edema, inflammation, proliferation, fibrosis at the postoperative 72nd hour and hemorrhage, edema, inflammation, proliferation, and fibrosis on the postoperative day 7 (p < 0,0042). Talc produced significant edema compared to oxytetracycline on the postoperative day 7. On contralateral side, oxytetracycline and talc produced significant hemorrhage on the postoperative day 7 (p < 0.0042). Conclusions Both agents were shown to produce pulmonary lesions. In acute phase, the pulmonary side effects of oxytetracycline were more pronounced, whereas the side effects of talc were prolonged to subacute phase. We propose that the occasional side effects in humans may be related to these changes as were observed in our rat model, and like talc, oxytetracycline must be used cautiously in patients with limited respiratory function. PMID:21144032

Enriched adhesion of talc/ZnO nanocomposites on cotton fabric assisted by aloe-vera for bio-medical application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Selvakumar, D.; Yogamalar, N. R.; Jayavel, R., E-mail: rjvel@annauniv.edu

Synthesis and characterization of talc/ZnO nanocomposites with the assistance of aloe-vera are investigated by structural and morphological studies. The crystal structure and the phase analysis of ZnO and talc are characterized and confirmed by X-ray diffraction (XRD) analysis. The average crystallite size estimation from the Scherrer formula and the particle size analysis clearly predicts that the size of the ZnO declines when aloe-vera is used as a capping molecule in comparison to the commercially available ZnO. The reduced crystallite size of ZnO renders a stable cohesion with the talc composition and the presence of distinct functional group pyridines/ammonia in themore » synthesized nanocomposites enriches the good adhesion between the as-synthesized material and cotton fabric. The adhesion and homogeneous distribution of talc/ZnO nanocomposites on the cotton fabric are inferred from the scanning electron microscopy (SEM) results. The basic studies and characterizations would pave way for futuristic bio-medical application.« less

Heat capacity from 12 to 305°K and entropy of talc and tremolite

USGS Publications Warehouse

Robie, R.A.; Stout, J.W.

1963-01-01

The heat capacities of talc, Mg3Si4O10(OH)2, and tremolite, Ca2Mg6Si8O22(OH)2, have been measured between 12 and 305??K. Smoothed values of heat capacity, entropy, enthalpy, and free energy are tabulated. At 298.15?? K. the values of the thermodynamic functions are: talc, Cp?? = 76.89 ?? 0.23 cal. deg.-1 mole-1, S?? = 62.33 ?? 0.19 cal. deg.-1 mole-1, H?? - H6?? = 11,206 ?? 34 cal. mole-1; tremolite, Cp?? = 156.7 ?? 0.6 cal. deg.-1 mole-1, S?? = 131.2 ?? 0.5 cal. deg.-1 mole-1, H?? - H6?? = 23,335 ?? 90 cal. mole-1. From the equilibrium data of Bowen and Tuttle and the entropy of talc, the heat of formation of talc from MgO, SiO2, and H2O (liq.) is calculated to be ??H??f298 = -43.6 ?? 1 kcal.

Enriched adhesion of talc/ZnO nanocomposites on cotton fabric assisted by aloe-vera for bio-medical application

NASA Astrophysics Data System (ADS)

Selvakumar, D.; Thenammai, A. N.; Yogamalar, N. R.; Hemamalini, R.; Jayavel, R.

2015-06-01

Synthesis and characterization of talc/ZnO nanocomposites with the assistance of aloe-vera are investigated by structural and morphological studies. The crystal structure and the phase analysis of ZnO and talc are characterized and confirmed by X-ray diffraction (XRD) analysis. The average crystallite size estimation from the Scherrer formula and the particle size analysis clearly predicts that the size of the ZnO declines when aloe-vera is used as a capping molecule in comparison to the commercially available ZnO. The reduced crystallite size of ZnO renders a stable cohesion with the talc composition and the presence of distinct functional group pyridines/ammonia in the synthesized nanocomposites enriches the good adhesion between the as-synthesized material and cotton fabric. The adhesion and homogeneous distribution of talc/ZnO nanocomposites on the cotton fabric are inferred from the scanning electron microscopy (SEM) results. The basic studies and characterizations would pave way for futuristic bio-medical application.

Infrared spectroscopic study of the synthetic Mg-Ni talc series

NASA Astrophysics Data System (ADS)

Blanchard, Marc; Méheut, Merlin; Delon, Louise; Poirier, Mathilde; Micoud, Pierre; Le Roux, Christophe; Martin, François

2018-05-01

Five talc samples [(Mg,Ni)3Si4O10(OH)2] covering the entire Mg-Ni solid solution were synthesized following a recently developed and patented process (Dumas et al., Process for preparing a composition comprising synthetic mineral particles and composition, 2013a; Procédé de préparation d'une composition comprenant des particules minérales synthétiques et composition, 2013b), which produces sub-micron talc particles replying to industrial needs. Near- and mid-infrared spectra were collected and compared to infrared spectra modeled from first-principles calculations based on density functional theory. The good agreement between experimental and theoretical spectra allowed assigning unambiguously all absorption bands. We focused in particular on the four main OH stretching bands, which represent good probes of their local physical and chemical environment. The description of the vibrational modes at the origin of these absorption bands and the theoretical determination of absorption coefficients provide a firm basis for quantifying the talc chemical composition from infrared spectroscopy and for discussing the distribution of divalent cations in the octahedral sheet. Results confirm that these synthetic talc samples have a similar structure as natural talc, with a random distribution of Mg and Ni atoms. They only differ from natural talc by their hydrophilic character, which is due to their large proportion of reactive sites on sheet edges due to sub-micronic size of the particles. Therefore, the contribution on infrared spectra of hydroxyls adsorbed on edge sites has also been investigated by computing the infrared signature of hydroxyls of surface models.

Observational analysis on inflammatory reaction to talc pleurodesis: Small and large animal model series review

PubMed Central

Vannucci, Jacopo; Bellezza, Guido; Matricardi, Alberto; Moretti, Giulia; Bufalari, Antonello; Cagini, Lucio; Puma, Francesco; Daddi, Niccolò

2018-01-01

Talc pleurodesis has been associated with pleuropulmonary damage, particularly long-term damage due to its inert nature. The present model series review aimed to assess the safety of this procedure by examining inflammatory stimulus, biocompatibility and tissue reaction following talc pleurodesis. Talc slurry was performed in rabbits: 200 mg/kg checked at postoperative day 14 (five models), 200 mg/kg checked at postoperative day 28 (five models), 40 mg/kg, checked at postoperative day 14 (five models), 40 mg/kg checked at postoperative day 28 (five models). Talc poudrage was performed in pigs: 55 mg/kg checked at postoperative day 60 (18 models). Tissue inspection and data collection followed the surgical pathology approach currently used in clinical practice. As this was an observational study, no statistical analysis was performed. Regarding the rabbit model (Oryctolagus cunicoli), the extent of adhesions ranged between 0 and 30%, and between 0 and 10% following 14 and 28 days, respectively. No intraparenchymal granuloma was observed whereas, pleural granulomas were extensively encountered following both talc dosages, with more evidence of visceral pleura granulomas following 200 mg/kg compared with 40 mg/kg. Severe florid inflammation was observed in 2/10 cases following 40 mg/kg. Parathymic, pericardium granulomas and mediastinal lymphadenopathy were evidenced at 28 days. At 60 days, from rare adhesions to extended pleurodesis were observed in the pig model (Sus Scrofa domesticus). Pleural granulomas were ubiquitous on visceral and parietal pleurae. Severe spotted inflammation among the adhesions were recorded in 15/18 pigs. Intraparenchymal granulomas were observed in 9/18 lungs. Talc produced unpredictable pleurodesis in both animal models with enduring pleural inflammation whether it was performed via slurry or poudrage. Furthermore, talc appeared to have triggered extended pleural damage, intraparenchymal nodules (porcine poudrage) and mediastinal migration (rabbit slurry). PMID:29403549

The influence of heterogeneous nucleation on the surface crystallization of guaifenesin from melt extrudates containing Eudragit L10055 or Acryl-EZE.

PubMed

Bruce, Caroline D; Fegely, Kurt A; Rajabi-Siahboomi, Ali R; McGinity, James W

2010-05-01

The objective of this study was to investigate the influence of talc and humidity conditions during storage on the crystal growth of guaifenesin on the surface of melt-extruded matrix tablets. Tablets consisted of the model drug guaifenesin in a matrix of either Acryl-EZE(R) or Eudragit(R) L10055 and either no talc, 25% or 50% talc. After processing, the hot-melt-extruded matrix tablets were supersaturated with amorphous guaifenesin, which resulted in the development of guaifenesin drug crystals on exposed surfaces of the tablet during storage (all tablets were stored at 24 degrees C). A previously developed, quantitative test was used to assay for surface guaifenesin. In tablets with a drug-to-polymer ratio of 19:81, talc-containing tablets exhibited an earlier onset of crystal growth (storage at 17% relative humidity). The presence of talc also increased the amount of surface crystallization and was independent of the talc concentration, since the talc levels used in this study exceeded the critical nucleant concentration. Additional non-melting components did not have an additive effect on surface crystal growth. High humidity during storage (78%) increased guaifenesin crystallization, but moisture uptake of tablets did not correlate with increased drug recrystallization. When storage at 17% relative humidity was interrupted for 3days by storage at 78% relative humidity before the tablets were returned to their previous low RH storage conditions, crystal growth quickly increased during the high RH interval and remained at an elevated level throughout the remaining storage period. A similar intermediate period of low, 17% relative humidity in tablets stored before and after that time at 78% RH did not affect surface crystallization levels. The effects of humidity and talc on the crystallization of guaifenesin from melt-extruded dosage forms supersaturated with amorphous drug were ascribed to heterogeneous nucleation.

Phase III intergroup study of talc poudrage vs talc slurry sclerosis for malignant pleural effusion.

PubMed

Dresler, Carolyn M; Olak, Jemi; Herndon, James E; Richards, William G; Scalzetti, Ernest; Fleishman, Stewart B; Kernstine, Kemp H; Demmy, Todd; Jablons, David M; Kohman, Leslie; Daniel, Thomas M; Haasler, George B; Sugarbaker, David J

2005-03-01

To demonstrate the efficacy, safety, and appropriate mode of instillation of talc for sclerosis in treatment of malignant pleural effusions (MPEs). A prospective, randomized trial was designed to compare thoracoscopy with talc insufflation (TTI) to thoracostomy and talc slurry (TS) for patients with documented MPE. The primary end point was 30-day freedom from radiographic MPE recurrence among surviving patients whose lungs initially re-expanded > 90%. Morbidity, mortality, and quality of life were also assessed. Of 501 patients registered, those eligible were randomized to TTI (n = 242) or TS (n = 240). Patient demographics and primary malignancies were similar between study arms. Overall, there was no difference between study arms in the percentage of patients with successful 30-day outcomes (TTI, 78%; TS, 71%). However, the subgroup of patients with primary lung or breast cancer had higher success with TTI than with TS (82% vs 67%). Common morbidity included fever, dyspnea, and pain. Treatment-related mortality occurred in nine TTI patients and seven TS patients. Respiratory complications were more common following TTI than TS (14% vs 6%). Respiratory failure was observed in 4% of TS patients and 8% of TTI patients, accounting for five toxic deaths and six toxic deaths, respectively. Quality-of-life measurement demonstrated less fatigue with TTI than TS. Patient ratings of comfort and safety were also higher for TTI, but there were no differences on perceived value or convenience of the procedures. Both methods of talc delivery are similar in efficacy; TTI may be better for patients with either a lung or breast primary. The etiology and incidence of respiratory complications from talc need further exploration.

High Density Polyethylene Composites Reinforced with Hybrid Inorganic Fillers: Morphology, Mechanical and Thermal Expansion Performance

PubMed Central

Huang, Runzhou; Xu, Xinwu; Lee, Sunyoung; Zhang, Yang; Kim, Birm-June; Wu, Qinglin

2013-01-01

The effect of individual and combined talc and glass fibers (GFs) on mechanical and thermal expansion performance of the filled high density polyethylene (HDPE) composites was studied. Several published models were adapted to fit the measured tensile modulus and strength of various composite systems. It was shown that the use of silane-modified GFs had a much larger effect in improving mechanical properties and in reducing linear coefficient of thermal expansion (LCTE) values of filled composites, compared with the use of un-modified talc particles due to enhanced bonding to the matrix, larger aspect ratio, and fiber alignment for GFs. Mechanical properties and LCTE values of composites with combined talc and GF fillers varied with talc and GF ratio at a given total filler loading level. The use of a larger portion of GFs in the mix can lead to better composite performance, while the use of talc can help lower the composite costs and increase its recyclability. The use of 30 wt % combined filler seems necessary to control LCTE values of filled HDPE in the data value range generally reported for commercial wood plastic composites. Tensile modulus for talc-filled composite can be predicted with rule of mixture, while a PPA-based model can be used to predict the modulus and strength of GF-filled composites. PMID:28788322

Talcum powder poisoning

MedlinePlus

... powder As a filler in street drugs, like heroin Other products may also contain talc. ... have developed serious lung damage and cancer. Injecting heroin that contains talc into a vein may lead ...

The talc, soapstone, and asbestos deposits of Massachusetts

USGS Publications Warehouse

Chute, Newton Earl

1969-01-01

Several talc and soapstone deposits were worked in Massachusetts from about 1810 to 1922. Most of these deposits are in the Chester Amphibolite, or in serpentine lenses in or adjacent to the amphibolite along a belt that extends north-south across the State from Rowe to West Granville; it appears to be a continuation of the Vermont talc belt. The only deposits outside of this belt that have been worked are a talc and soapstone deposit in the north-west corner of Hinsdale and soapstone deposits on the east side of Soapstone Hill in the western part of Petersham. Very little asbestos has been produced in Massachusetts. A small amount of anthophyllite asbestos was obtained from the deposit in Hinsdale, and from a deposit in southwestern Pelham. The talc and soapstone deposits of Massachusetts were formed from serpentine and possibly from amphibolite, schist, and dolomitic limestone. Those fromed from serpentine are mainly at the ends of the serpentine bodies, and those that appear to have been formed from amphibolite or schist are on the faults and folds.

[Current treatment strategy in malignant pleural effusion].

PubMed

Türler, A; Walter, M; Schmitz-Rixen, T

1996-01-01

Malignant pleural effusions are a grave consequence of advanced cancer disease. The successful suppression of pleural fluid reaccumulation can make a major contribution to the management and palliative care of patients with disseminated cancer. Many treatment concepts have been reported in the literature. The recommended therapy in malignant pleural effusions consists of intrapleural instillation of a sclerotic agent to produce pleurodesis. Different substances have been used, including tetracyclines, cytostatic agents, fibrin, talc, Corynebacterium parvum, cytokines and others. We reviewed the most frequently used techniques of pleurodesis in order to define the most effective treatment concept. In 15 prospective randomized trials the success rates varied from 13% with bleomycin to 100% with talc or Corynebacterium parvum. Talc was superior to other agents in 6 of 6, Corynebacterium parvum in 3 of 4 and bleomycin or tetracycline only in 3 of 8 studies. Adverse effects were frequently observed with cytostatic agents, but were very rare in the case of talc or fibrin instillation. Comparing the recently published data pleurodesis with talc appears to be the most effective treatment strategy, followed by Corynebacterium parvum, bleomycin and tetracycline.

[Production and characteristics of bacteria-labeled talc dust for experimental air hygiene studies].

PubMed

Ohgke, H; Oldenburg, B; Gropengiesser, R; Herbst, M

1983-04-01

Freeze-drying of suspensions of Micrococcus luteus together with talc yields bacteria-labelled dust. This material can be used in experimental air hygiene. Loss of viability due to drying in air during experiments can be expected to be negligible. A wide range of particle diameters (1 to greater than 23 micron) is available. Scanning electron microscopy shows the bacteria sticking on talc particles after freeze-drying (Fig. 3a + b). Viable counts of the material decreased very slowly on storage.

Management of malignant pleural effusion.

PubMed

Chen, Hongbin; Brahmer, Julie

2008-07-01

Malignant pleural effusion (MPE) often presents in patients with cancer at an advanced stage and thus carries a poor prognosis. This review updates the current knowledge on the management of MPE, focusing on recent literature about the efficacy and safety of the most common methods, including pleurodesis by either thoracoscopy with talc insufflation or thoracostomy with talc slurry, use of an indwelling pleural catheter, and intrapleural chemotherapy. Talc remains the agent of choice in pleurodesis, although the use of alternative agents continues to be explored. The choice of procedure to achieve pleurodesis depends on careful patient selection based on predictive factors and individual characteristics. Talc pleuro-desis is relatively well tolerated and safe, as is an indwelling pleural catheter, in an appropriate patient population. Because MPE is a common problem in cancer patients, future research with more randomized, prospective designs and innovative interventions is needed.

Kinetics of volatile extraction from carbonaceous chondrites: Dehydration of talc

NASA Technical Reports Server (NTRS)

Bose, Kunal; Ganguly, Jibamitra

1991-01-01

Carbonaceous chondrites are believed to be the primary constituents of near-Earth asteroids and Phobos and Deimos, and are potential resources of fuels that may be exploited for future planetary missions. Calculations of equilibrium phase relations suggest that talc (Ta) and antigorite (Ant) are likely to be the major hydrous phases in the C1 and C2 meteorites (Ganguly and Saxena, 1989), which constitute the most volatile rich classes of carbonaceous chondrites. The dehydration kinetics of talc are studied as a function of temperature, grain size, composition and fluid fugacity, as part of a systematic study of the reaction kinetics of the volatile bearing phases that are either known or likely to be present in carbonaceous chondrites. The dehydration kinetics were investigated at 1 bar, 775 to 875 C by monitoring the in-situ weight loss as a function of time of a natural talc. The talc platelets had a dimension of 0.8 to 1 micron. The run durations varied from 233.3 hours at 775 C (48 percent dehydration) to 20.8 hours at 875 C (80 pct. dehydration). The results can be adequately represented by a given rate equation. Theoretical analysis suggests that the reduction in the concentration of H2O in the environment of dehydrating talc, as would be encountered in processing chondritic materials, will have negligible effect on the rate of dehydration, unless there is a change of reaction mechanism owing to the presence of other volatile species.

Efficacy and cost of video-assisted thoracoscopic partial pleurectomy versus talc pleurodesis in patients with malignant pleural mesothelioma (MesoVATS): an open-label, randomised, controlled trial.

PubMed

Rintoul, Robert C; Ritchie, Andrew J; Edwards, John G; Waller, David A; Coonar, Aman S; Bennett, Maxine; Lovato, Eleonora; Hughes, Victoria; Fox-Rushby, Julia A; Sharples, Linda D

2014-09-20

Malignant pleural mesothelioma incidence continues to rise, with few available evidence-based therapeutic options. Results of previous non-randomised studies suggested that video-assisted thoracoscopic partial pleurectomy (VAT-PP) might improve symptom control and survival. We aimed to compare efficacy in terms of overall survival, and cost, of VAT-PP and talc pleurodesis in patients with malignant pleural mesothelioma. We undertook an open-label, parallel-group, randomised, controlled trial in patients aged 18 years or older with any subtype of confirmed or suspected mesothelioma with pleural effusion, recruited from 12 hospitals in the UK. Eligible patients were randomly assigned (1:1) to either VAT-PP or talc pleurodesis by computer-generated random numbers, stratified by European Organisation for Research and Treatment of Cancer risk category (high vs low). The primary outcome was overall survival at 1 year, analysed by intention to treat (all patients randomly assigned to a treatment group with a final diagnosis of mesothelioma). This trial is registered with ClinicalTrials.gov, number NCT00821860. Between Oct 24, 2003, and Jan 24, 2012, we randomly assigned 196 patients, of whom 175 (88 assigned to talc pleurodesis, 87 assigned to VAT-PP) had confirmed mesothelioma. Overall survival at 1 year was 52% (95% CI 41-62) in the VAT-PP group and 57% (46-66) in the talc pleurodesis group (hazard ratio 1·04 [95% CI 0·76-1·42]; p=0·81). Surgical complications were significantly more common after VAT-PP than after talc pleurodesis, occurring in 24 (31%) of 78 patients who completed VAT-PP versus ten (14%) of 73 patients who completed talc pleurodesis (p=0·019), as were respiratory complications (19 [24%] vs 11 [15%]; p=0·22) and air-leak beyond 10 days (five [6%] vs one [1%]; p=0·21), although not significantly so. Median hospital stay was longer at 7 days (IQR 5-11) in patients who received VAT-PP compared with 3 days (2-5) for those who received talc pleurodesis (p<0·0001). VAT-PP is not recommended to improve overall survival in patients with pleural effusion due to malignant pleural mesothelioma, and talc pleurodesis might be preferable considering the fewer complications and shorter hospital stay associated with this treatment. BUPA Foundation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantitative texture analysis of talc in mantle hydrated mylonites

NASA Astrophysics Data System (ADS)

Benitez-Perez, J. M.; Gomez Barreiro, J.; Wenk, H. R.; Vogel, S. C.; Soda, Y.; Voltolini, M.; Martinez-Catalan, J. R.

2014-12-01

A quantitative texture analysis of talc-serpentinite mylonites developed in highly deformed ultramafic rocks from different orogenic contexts have been done with neutorn diffraction at HIPPO (Los Álamos National Laboratory). Mineral assemblage, metamorphic evolution and deformative fabric of these samples could be correlated with those verified along the shallow levels (<100km; <5GPa) of a subduction zone. The hydration of mantle (ultramafic) rocks at those levels it is likely to occur dynamically, with important implications on seismogenesis. Given the high anisotropy of the major phases in the samples (i.e. talc and antigorite) it is expected to influence seismic anisotropy of the whole system, in the presence of texture. However to date there was no data on the crystallographic preferred orientation of talc and examples of antigorite textures are very limited. We explore the contribution of talc texture to the seismic anisotropy of mantle hydrated mylonites. Acknowledgements: This work has been funded by research project CGL2011-22728 of Spanish Ministry of Economy and Competitiveness. JGB and JMBP are grateful to the Ramón y Cajal and FPI funding programs. Access to HIPPO (LANSCE) to conduct diffraction experiments is kindly acknowledged.

Blends of HDPE wastes: study of the properties.

PubMed

Sánchez-Soto, M; Rossa, A; Sánchez, A J; Gámez-Pérez, J

2008-12-01

In this work we have analysed the properties of blends of recycled high-density polyethylene (HDPE) filled with talc. We have used two kinds of polymer matrices. The first one came entirely from ground injection moulded parts whereas the second was bimodal, incorporating 80% of the previous HDPE and 20% of recycled HDPE coming from bottles. We have also used two kinds of commercial talc characterized by a medium particle size of 2 microm and 10 microm, respectively. The amount of talc added to both matrices weighed of 10% and 20%. With regards to the mechanical properties of the analysed composites, greater values of Young's modulus and break stresses were found using a smaller particle size and higher talc content. On the other hand, the combination of the two HDPEs with very different viscosities produced a notable increase in the strain at break and in the absorbed energy; both measured at high and low strain rates. Despite the differences in viscosities between the two HDPEs, we did not observe separation of phases during either the processing or testing. Under impact loading, the higher energy absorption in the composites was observed when the finest talc grade with a 10% content weight was added to the bimodal matrix.

Comparing cost of indwelling pleural catheter vs talc pleurodesis for malignant pleural effusion.

PubMed

Penz, Erika D; Mishra, Eleanor K; Davies, Helen E; Manns, Braden J; Miller, Robert F; Rahman, Najib M

2014-10-01

Malignant pleural effusion is associated with short life expectancy and significant morbidity. A randomized controlled trial comparing indwelling pleural catheters (IPCs) with talc pleurodesis found that IPCs reduced in-hospital time and the need for additional procedures but were associated with excess adverse events. Using data from the clinical trial, we compared costs associated with use of IPCs and with talc pleurodesis. Resource use and adverse events were captured through case report forms over the 1-year trial follow-up. Costs for outpatient and inpatient visits, diagnostic imaging, nursing, and doctor time were obtained from the UK National Health Service reference costs and University of Kent's Unit Costs of Health and Social Care 2011 and inflated to 2013 using the UK Consumer Price Index. Procedure supply costs were obtained from the manufacturer. Difference in mean costs was compared using nonparametric bootstrapping. All costs were converted to US dollars using the Organisation for Economic Co-operation and Development Purchasing Power Parity Index. Overall mean cost (SD) for managing patients with IPCs and talc pleurodesis was $4,993 ($5,529) and $4,581 ($4,359), respectively. The incremental mean cost difference was $401, with 95% CI of -$1,387 to $2,261. The mean cost related to ongoing drainage in the IPC group was $1,011 ($732) vs $57 ($213) in the talc pleurodesis group (P = .001). This included the cost of drainage bottles, dressing changes in the first month, and catheter removal. There was no significant difference in cost of the initial intervention or adverse events between the groups. For patients with survival < 14 weeks, IPC is significantly less costly than talc pleurodesis, with mean cost difference of -$1,719 (95% CI, -$3,376 to -$85). There is no significant difference in the mean cost of managing patients with IPCs compared with talc pleurodesis. For patients with limited survival, IPC appears less costly. isrctn.org; No.: ISRCTN87514420; URL: www.isrctn.org.

Mortality of Talc Miners and Millers From Val Chisone, Northern Italy: An Updated Cohort Study.

PubMed

Pira, Enrico; Coggiola, Maurizio; Ciocan, Catalina; Romano, Canzio; La Vecchia, Carlo; Pelucchi, Claudio; Boffetta, Paolo

2017-07-01

The aim of this study was to update the analysis of mortality of a cohort of talc miners and millers in Northern Italy. We analyzed the mortality during 1946 to 2013 of 1722 male workers in an asbestos-free talc mine (1166 miners and 556 millers) employed during 1946 to 1995. The overall standardized mortality ratio (SMR) was 1.24 [95% confidence interval (95% CI) 1.17 to 1.32]; no deaths were observed from pleural cancer; mortality from lung cancer was not increased. Mortality from pneumoconiosis was increased (SMR 26.62; 95% CI 20.71 to 33.69), in particular among miners, and was associated with duration of employment and time since first employment. We confirmed the lack of association between exposure to asbestos-free talc, lung cancer, and mesothelioma. Increased mortality from pneumoconiosis among miners is attributable to past exposure to silica.

Transpupillary Argon Laser Cyclophotocoagulation in a Refractory Traumatic Glaucoma Patient with Aphakia and Aniridia

PubMed Central

Uzunel, Umut Duygu; Yüce, Berna; Küsbeci, Tuncay; Ateş, Halil

2016-01-01

We present a case of transpupillary argon laser cyclophotocoagulation (TALC) in a patient with traumatic aniridia and aphakia secondary to blunt trauma who had previous bilateral trabeculectomy. Four months after the trauma the patient’s intraocular pressure (IOP) rose to 35 mmHg despite topical antiglaucomatous medication. Inferior 180 degrees cyclophotocoagulation was performed with transpupillary argon laser in the first session and his IOP fell to values of 12-17 mmHg. Twelve weeks after TALC, his IOP rose to 22 mmHg and we had to apply TALC to the residual ciliary processes. Seven months later his IOP was 13 mmHg with topical dorzolamide/timolol and latanoprost administration. TALC may be an effective treatment alternative for lowering IOP in patients with visible ciliary processes who do not respond to conventional medical or laser treatment. PMID:27800256

Case report: silicatosis in a carpet installer.

PubMed

Szeinuk, Jaime; Wilk-Rivard, Elizabeth J

2007-06-01

Chronic exposure to talc in the course of carpet installation can result in pneumoconiosis. We present a case of a young carpet installer who was diagnosed with silicatosis of the lung. Review of occupational history revealed that the patient had been working as a carpet installer for approximately 15 years, since he was 15 years of age. The patient was exposed to talc in the course of his work. Exposure to talc in the course of carpet installation has not been reported as a possible cause of pneumoconiosis. In this article we review different causes of silicatosis and discuss chronic exposure in the course of carpet installation and development of pneumoconiosis. In addition, we also review the relevance of mycobacterial infection in cases of silicosis and silicatosis. Exposure to talc in the course of carpet installation should be added to conditions that can cause pneumoconioses, specifically silicatosis of the lung.

Deposition of talc - kerolite-smectite - smectite at seafloor hydrothermal vent fields: Evidence from mineralogical, geochemical and oxygen isotope studies

USGS Publications Warehouse

Dekov, V.M.; Cuadros, J.; Shanks, Wayne C.; Koski, R.A.

2008-01-01

Talc, kerolite-smectite, smectite, chlorite-smectite and chlorite samples from sediments, chimneys and massive sulfides from six seafloor hydrothermal areas have been analyzed for mineralogy, chemistry and oxygen isotopes. Samples are from both peridotite- and basalt-hosted hydrothermal systems, and basaltic systems include sediment-free and sediment-covered sites. Mg-phyllosilicates at seafloor hydrothermal sites have previously been described as talc, stevensite or saponite. In contrast, new data show tri-octahedral Mg-phyllosilicates ranging from pure talc and Fe-rich talc, through kerolite-rich kerolite-smectite to smectite-rich kerolite-smectite and tri-octahedral smectite. The most common occurrence is mixed-layer kerolite-smectite, which shows an almost complete interstratification series with 5 to 85% smectitic layers. The smectite interstratified with kerolite is mostly tri-octahedral. The degree of crystal perfection of the clay sequence decreases generally from talc to kerolite-smectite with lower crystalline perfection as the proportion of smectite layers in kerolite-smectite increases. Our studies do not support any dependence of the precipitated minerals on the type/subtype of hydrothermal system. Oxygen isotope geothermometry demonstrates that talc and kerolite-smectite precipitated in chimneys, massive sulfide mounds, at the sediment surface and in open cracks in the sediment near seafloor are high-temperature (> 250????C) phases that are most probably the result of focused fluid discharge. The other end-member of this tri-octahedral Mg-phyllosilicate sequence, smectite, is a moderate-temperature (200-250????C) phase forming deep within the sediment (??? 0.8??m). Chlorite and chlorite-smectite, which constitute the alteration sediment matrix around the hydrothermal mounds, are lower-temperature (150-200????C) phases produced by diffuse fluid discharge through the sediment around the hydrothermal conduits. In addition to temperature, other two controls on the precipitation of this sequence are the silica activity and Mg/Al ratio (i.e. the degree of mixing of seawater with hydrothermal fluid). Higher silica activity favors the formation of talc relative to tri-octahedral smectite. Vent structures and sedimentary cover preclude complete mixing of hydrothermal fluid and ambient seawater, resulting in lower Mg/Al ratios in the interior parts of the chimneys and deeper in the sediment which leads to the precipitation of phyllosilicates with lower Mg contents. Talc and kerolite-smectite have very low trace- and rare earth element contents. Some exhibit a negative or flat Eu anomaly, which suggests Eu depletion in the original hydrothermal fluid. Such Eu depletion could be caused by precipitation of anhydrite or barite (sinks for Eu2+) deeper in the system. REE abundances and distribution patterns indicate that chlorite and chlorite-smectite are hydrothermal alteration products of the background turbiditic sediment. ?? 2007 Elsevier B.V. All rights reserved.

Effect of reprocessing cycles on the degradation of polypropylene copolymer filled with talc or montmorillonite during injection molding process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demori, R.; Mauler, R. S., E-mail: raquel.mauler@ufrgs.br; Ashton, E.

Mechanical recycling of polymeric materials is a favorable technique resulting in economic and environmental benefits, especially in the case of polymers with a high production volume as the polypropylene copolymer (PP). However, recycling by reprocessing techniques can lead to thermal, mechanical or thermo-oxidative degradation that can affect the structure of the polymer and subsequently the material properties. PP filled with montmorillonite (MMT) or talc are widely produced and studied, however, its degradation reactions by reprocessing cycles are poorly studied so far. In this study, the effects of reprocessing cycles in the structure and in the properties of the PP/MMT andmore » PP/Talc were evaluated. The samples were mixed with 5% talc or MMT Cloisite C15A in a twin-screw extrusion. After extrusion, this filled material was submitted to five reprocessing cycles through an injection molding process. In order to evaluate the changes induced by reprocessing techniques, the samples were characterized by DSC, FT-IR, Izod impact and tensile strength tests. The study showed that Young modulus, elongation at brake and Izod impact were not affected by reprocessing cycles, except when using talc. In this case, the elongation at brake reduced until the fourth cycle, showing rigidity increase. The DSC results showed that melting and crystallization temperature were not affected. A comparison of FT-IR spectra of the reprocessed indicated that in both samples, between the first and the fifth cycle, no noticeable change has occurred. Thus, there is no evidence of thermo oxidative degradation. In general, these results suggest that PP reprocessing cycles using MMT or talc does not change the material properties until the fifth cycle.« less

21 CFR 73.1550 - Talc.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... (2) Color additive mixtures for drug use made with talc may contain only those diluents listed in this subpart as safe and suitable for use in color additive mixtures for coloring drugs. (b... AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES...

Synthetic Talc and Talc-Like Structures: Preparation, Features and Applications.

PubMed

Claverie, Marie; Dumas, Angela; Carême, Christel; Poirier, Mathilde; Le Roux, Christophe; Micoud, Pierre; Martin, François; Aymonier, Cyril

2018-01-12

This contribution gives a comprehensive review about the progress in preparation methods, properties and applications of the different synthetic talc types: i) crystalline nanotalc synthesized by hydrothermal treatment; ii) amorphous and/or short-range order nanotalc obtained by precipitation, and iii) organic-inorganic hybrid talc-like structures obtained through a sol-gel process or a chemical grafting. Several advantages of nanotalc such as high chemical purity, high surface area, tunable submicronic size, high thermal stability, and hydrophilic character (leading to be the first fluid mineral) are emphasized. Synthetic nanotalc applications are also considered including its use as nanofiller in composite materials, as absorbers of organic compounds, as anticorrosion coatings and as agents for cosmetic applications. Regarding their high industrial application potential, intensive research has been carried out to better understand their behavior and develop processes to produce them. To facilitate further research and development, scientific and technical challenges are discussed in this Review article. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Disseminated talc granulomatosis. An unusual finding in a patient with acquired immunodeficiency syndrome and fatal cytomegalovirus infection.

PubMed

Lewis, J H; Sundeen, J T; Simon, G L; Schulof, R S; Wand, G S; Gelfand, R L; Miller, H; Garrett, C T; Jannotta, F S; Orenstein, J M

1985-02-01

The association of disseminated magnesium silicate talc granulomatosis and acquired immunodeficiency syndrome is reported in a male homosexual who used intravenous drugs and who died of overwhelming cytomegalovirus (CMV) infection. Autopsy findings included widespread deposition of talc crystals in the lungs, liver, lymph nodes, bone marrow, and spleen. Typical CMV inclusions were seen in the lungs, kidneys, adrenal glands, gastrointestinal tract, and right eye. There was no evidence of malignancy. Analysis of peripheral blood neutrophil function revealed impaired chemotaxis and chemokinesis, but opsonophagocytosis had remained normal. The CMV infection in the small bowel was extensive and resulted in severe destruction of the muscularis propria and neural plexi, leading to marked dilatation and persistent diarrhea. The terminal course was marked by intractable hypotension, pneumonitis, and malnutrition, which could be attributed respectively to CMV involvement of the adrenal glands, lungs, and small bowel. The etiology and possible role of systemic talc granulomatosis in the development of immunosuppressive illness is reported herein.

Thermodynamic properties of anthophyllite and talc: corrections and discussion of calorimetric data

USGS Publications Warehouse

Hemingway, B.S.

1991-01-01

Arithmetic errors in calculating heat capacity values (Krupka, 1984; Krupka et al, 1985a) for anthophyllite and several errors in the Hess cycles utilized to derive enthalpies of formation of anthophyllite and talc are identified, and revised values are reported. -from Author

Environmental Particle Emissions due to Automated Drilling of Polypropylene Composites and Nanocomposites Reinforced with Talc, Montmorillonite and Wollastonite

NASA Astrophysics Data System (ADS)

Starost, K.; Frijns, E.; Laer, J. V.; Faisal, N.; Egizabal, A.; Elizextea, C.; Nelissen, I.; Blazquez, M.; Njuguna, J.

2017-05-01

In this study, the effect on nanoparticle emissions due to drilling on Polypropylene (PP) reinforced with 20% talc, 5% montmorillonite (MMT) and 5% Wollastonite (WO) is investigated. The study is the first to explore the nanoparticle release from WO and talc reinforced composites and compares the results to previously researched MMT. With 5% WO, equivalent tensile properties with a 10 % weight reduction were obtained relative to the reference 20% talc sample. The materials were fabricated through injection moulding. The nanorelease studies were undertaken using the controlled drilling methodology for nanoparticle exposure assessment developed within the European Commission funded SIRENA Life 11 ENV/ES/506 project. Measurements were taken using CPC and DMS50 equipment for real-time characterization and measurements. The particle number concentration (of particles <1000nm) and particle size distribution (4.87nm - 562.34nm) of the particles emitted during drilling were evaluated to investigate the effect of the silicate fillers on the particles released. The nano-filled samples exhibited a 33% decrease (MMT sample) or a 30% increase (WO sample) on the average particle number concentration released in comparison to the neat polypropylene sample. The size distribution data displayed a substantial percentage of the particles released from the PP, PP/WO and PP/MMT samples to be between 5-20nm, whereas the PP/talc sample emitted larger particle diameters.

Possible involvement of the transient receptor potential vanilloid type 1 channel in postoperative adhesive obstruction and its prevention by a kampo (traditional Japanese) medicine, daikenchuto.

PubMed

Tokita, Yohei; Yamamoto, Masahiro; Satoh, Kazuko; Nishiyama, Mitsue; Iizuka, Seiichi; Imamura, Sachiko; Kase, Yoshio

2011-01-01

This study focused on the localization of transient receptor potential vanilloid type 1 (TRPV1) in the intestines in postoperative adhesion model rats and investigated the underlying mechanism for the anti-adhesion action of daikenchuto (DKT), especially in relation to TRPV1. Postoperative intestinal adhesion was induced by sprinkling talc in the small intestine. The expression of TRPV1 mRNA was examined by in situ hybridization and real-time RT-PCR. The effects of DKT and its major ingredient, hydroxy sanshool, with or without ruthenium red, a TRP-channel antagonist, on talc-induced intestinal adhesions were evaluated. The level of TRPV1 mRNA was higher in the adhesion regions of talc-treated rats than in normal small intestine of sham-operated rats. Localization of TRPV1 mRNA expression was identified in the submucosal plexus of both sham-operated and talc-treated rats; and in talc-treated rats, it was observed also in the myenteric plexus and regions of adhesion. Capsaicin, DKT, and hydroxy sanshool significantly prevented formation of intestinal adhesions. The effects of DKT and hydroxy sanshool were abrogated by subcutaneous injection of ruthenium red. These results suggest that pharmacological modulation of TRPV1 might be a possible therapeutic option in postoperative intestinal adhesion, which might be relevant to the prevention of postoperative adhesive obstruction by DKT.

Comparison of talc-Celite and polyelectrolyte 60 in virus recovery from sewage: development of technique and experiments with poliovirus (type 1, Sabin)-contaminated multilitre samples.

PubMed

Sattar, S A; Westwood, J C

1976-11-01

For virus recovery from sewage, a mixture of talc and Celite was tested as a possible inexpensive substitute for polyelectrolyte 60 (PE 60). After adjustment of pH to 6 and the addition of 45-60 plaque forming units (PFU)/ml of poliovirus type I (Sabin) to the sewage sample under test, 100 ml of it was passed through either a PE 60 (400 mg) or a talc (300 mg)-Celite (100 mg) layer; the layer-adsorbed virus was eluted with 10 ml of 10% fetal calf serum (FCS) in saline (pH 7.2). In these experiments, PE 60 layers recovered 73-80% (mean 76%) of the input virus. In comparison, virus recoveries with the talc-Celite layers were 65-70% (mean 68%). Passage of 5 litres of raw sewage (containing 50 to 1.26 X 10(5) PFU/100 ml of the poliovirus) through the talc (15 g)-Celite (5 g) layers and virus elution with 50 ml of 10% FCS in saline gave virus recoveries of 33-63% (mean 49%). Except for pH adjustment and prefiltration through two layers of gauze to remove large solids, no other sample pretreatment was found to be necessary. Application of this technique to recovery of indigenous viruses from field samples of raw sewage and effluents has been highly satisfactory.

Interaction of divalent cations with basal planes and edge surfaces of phyllosilicate minerals: muscovite and talc.

PubMed

Yan, Lujie; Masliyah, Jacob H; Xu, Zhenghe

2013-08-15

Smooth basal plane and edge surfaces of two platy phyllosilicate minerals (muscovite and talc) were prepared successfully to allow accurate colloidal force measurement using an atomic force microscope (AFM), which allowed us to probe independently interactions of divalent cations with phyllosilicate basal planes and edge surfaces. The Stern potential of basal planes and edge surfaces was obtained by fitting the measured force profiles with the classical DLVO theory. The fitted Stern potential of the muscovite basal plane became less negative with increasing Ca(2+) or Mg(2+) concentration but did not reverse its sign even at Ca(2+) or Mg(2+) concentrations up to 5 mM. In contrast, the Stern potential of the muscovite edge surface reversed at Ca(2+) or Mg(2+) concentrations as low as 0.1 mM. The Stern potential of the talc basal plane became less negative with 0.1 mM Ca(2+) addition and nearly zero with 1 mM Ca(2+) addition. The Stern potential of talc edge surface became reversed with 0.1 mM Ca(2+) or 1 mM Mg(2+) addition, showing not only a different binding mechanism of talc basal planes and edge surfaces with Ca(2+) and Mg(2+), but also different binding mechanism between Ca(2+) and Mg(2+) ions with basal planes and edge surfaces. Copyright © 2013 Elsevier Inc. All rights reserved.

Characterization of Minerals: From the Classroom to Soils to Talc Deposits

ERIC Educational Resources Information Center

McNamee, Brittani D.

2013-01-01

This dissertation addresses different methods and challenges surrounding characterizing and identifying minerals in three environments: in the classroom, in soils, and in talc deposits. A lab manual for a mineralogy and optical mineralogy course prepares students for mineral characterization and identification by giving them the methods and tools…

Quantitative Determination of Fluorine Content in Blends of Polylactide (PLA)–Talc Using Near Infrared Spectroscopy

PubMed Central

Tamburini, Elena; Tagliati, Chiara; Bonato, Tiziano; Costa, Stefania; Scapoli, Chiara; Pedrini, Paola

2016-01-01

Near-infrared spectroscopy (NIRS) has been widely used for quantitative and/or qualitative determination of a wide range of matrices. The objective of this study was to develop a NIRS method for the quantitative determination of fluorine content in polylactide (PLA)-talc blends. A blending profile was obtained by mixing different amounts of PLA granules and talc powder. The calibration model was built correlating wet chemical data (alkali digestion method) and NIR spectra. Using FT (Fourier Transform)-NIR technique, a Partial Least Squares (PLS) regression model was set-up, in a concentration interval of 0 ppm of pure PLA to 800 ppm of pure talc. Fluorine content prediction (R2cal = 0.9498; standard error of calibration, SEC = 34.77; standard error of cross-validation, SECV = 46.94) was then externally validated by means of a further 15 independent samples (R2EX.V = 0.8955; root mean standard error of prediction, RMSEP = 61.08). A positive relationship between an inorganic component as fluorine and NIR signal has been evidenced, and used to obtain quantitative analytical information from the spectra. PMID:27490548

PLA and single component silicone rubber blends for sub-zero temperature blown film packaging applications

NASA Astrophysics Data System (ADS)

Meekum, Utai; Khiansanoi, Apichart

2018-06-01

The poly(lactic acid) (PLA) blend with single component silicone rubber in the presence of reactive amino silane coupling agent and polyester polyols plasticizer were studied. The manufacturing of film packaging for sub-zero temperature applications from the PLA blend was the main objective. The mechanical properties, especially the impact strengths, of PLA/silicone blends were significantly depended on the silicone loading. The outstanding impact strengths, tested at sub-zero temperature, of the blend having silicone content of 8.0 phr was achieved. It was chosen as the best candidate for the processability improvement. Adding the talc filler into the PLA/silicone blend to enhance the rheological properties was investigated. The ductility of the talc filled blends were decreased with increasing the filler contents. However, the shear viscosity of the blend was raised with talc loading. The blend loaded with 40 phr of talc filler was justified as the optimal formula for the blown film process testing and it was successfully performed with a few difficulties. The obtained blown film showed relative good flexibility in comparison with LDPE but it has low transparency.

Minimally invasive surgical treatment of malignant pleural effusions.

PubMed

Ciuche, Adrian; Nistor, Claudiu; Pantile, Daniel; Prof Horvat, Teodor

2011-10-01

Usually the pleural cavity contains a small amount of liquid (approximately 10 ml). Pleural effusions appear when the liquid production rate overpasses the absorption rate with a greater amount of liquid inside the pleural cavity. Between January 1998 to December 2008 we conducted a study in order to establish the adequate surgical treatment for MPEs. Effective control of a recurrent malignant pleural effusion can greatly improve the quality of life of the cancer patient. The present review collects and examines the clinical results of minimally invasive techniques designed to treat this problem. Patients with MPEs were studied according to several criteria. In our study we observed the superiority of intraoperative talc poudrage, probably due to a more uniform distribution of talc particles over the pleural surface. Minimal pleurotomy with thoracic drainage and instillation of a talc suspension is also a safe and effective technique and should be employed when there are contraindications for the thoracoscopic minimally invasive procedure. On the basis of comparisons involving effectiveness, morbidity, and convenience, we recommend the thoracoscopic insufflations of talc as a fine powder with pleural drainage as the procedure of choice.

Comparative study of talc poudrage versus pleural abrasion for the treatment of primary spontaneous pneumothorax†

PubMed Central

Moreno-Merino, Sergio; Congregado, Miguel; Gallardo, Gregorio; Jimenez-Merchan, Rafael; Trivino, Ana; Cozar, Fernando; Lopez-Porras, Marta; Loscertales, Jesus

2012-01-01

Primary spontaneous pneumothorax is a pathology mainly affecting healthy young patients. Clinical guidelines do not specify the type of pleurodesis that should be conducted, due to the lack of comparative studies on the different techniques. The aim of this study was to compare talc poudrage and pleural abrasion in the treatment of spontaneous pneumothorax. A retrospective comparative study was performed, including 787 patients with primary spontaneous pneumothorax. The 787 patients were classified into two groups: Group A (pleural abrasion) n = 399 and Group B (talc pleurodesis) n = 388. The variables studied were recurrence, surgical time, morbidity and in-hospital length of stay. Statistical analysis was done by an unpaired t-test and Fisher's exact test (SSPS 18.0). Statistically significant differences were observed in the variables: surgical time (A: 46 ± 12.3; B: 37 ± 11.8 min; P < 0.001); length of stay (A: 4.7 ± 2.5; B: 4.3 ± 1.8 days; P = 0.01); apical air camera (A: 25; B: 4; P < 0.001); pleural effusion (A: 6; B: 0; P = 0.05). Talc poudrage shows shorter surgical times and length of stay, and lower re-intervention rates. Morbidity is lower in patients with talc poudrage. Statistically significant differences were not observed in recurrence, persistent air leaks, atelectasis and haemothorax. PMID:22514256

Spontaneous doping on high quality talc-graphene-hBN van der Waals heterostructures

NASA Astrophysics Data System (ADS)

Mania, E.; Alencar, A. B.; Cadore, A. R.; Carvalho, B. R.; Watanabe, K.; Taniguchi, T.; Neves, B. R. A.; Chacham, H.; Campos, L. C.

2017-09-01

Steady doping, added to its remarkable electronic properties, would make graphene a valuable commodity in the solar cell market, as energy power conversion could be substantially increased. Here we report a graphene van der Waals heterostructure which is able to spontaneously dope graphene (p-type) up to n ~ 2.2  ×  1013 cm-2 while providing excellent charge mobility (μ ~ 25 000 cm2 V-1 s-1). Such properties are achieved via deposition of graphene on atomically flat layered talc, a natural and abundant dielectric crystal. Raman investigation shows a preferential charge accumulation on graphene-talc van der Waals heterostructures, which are investigated through the electronic properties of talc/graphene/hBN heterostructure devices. These heterostructures preserve graphene’s good electronic quality, verified by the observation of quantum Hall effect at low magnetic fields (B  =  0.4 T) at T  =  4.2 K. In order to investigate the physical mechanisms behind graphene-on-talc p-type doping, we performed first-principles calculations of their interface structural and electronic properties. In addition to potentially improving solar cell efficiency, graphene doping via van der Waals stacking is also a promising route towards controlling the band gap opening in bilayer graphene, promoting a steady n or p type doping in graphene and, eventually, providing a new path to access superconducting states in graphene, predicted to exist only at very high doping.

Identification of Foreign Particles in Human Tissues using Raman Microscopy.

PubMed

Campion, Alan; Smith, Kenneth J; Fedulov, Alexey V; Gregory, David; Fan, Yuwei; Godleski, John J

2018-06-12

The precise identification of foreign particles in tissue for patient care and research has been studied using polarized light microscopy, electron microscopy with X-ray analysis, and electron diffraction. The goal of this study was to unambiguously identify particles in tissues using a combina-tion of polarized light microscopy and Raman microscopy, which provides chemical composition and microstructural characterization of complex materials with submicron spatial resolution. We designed a model system of stained and unstained cells that contained birefringent talc particles, and systematically investigated the influence of slide and coverslip materials, laser wavelengths, and mounting media on the Raman spectra ob-tained. Hematoxylin and eosin stained slides did not produce useful results because of fluorescence interference from the stains. Unstained cell samples prepared with standard slides and coverslips produce high quality Raman spectra when excited at 532 nm; the spectra are uniquely as-signed to talc. We also obtain high quality Raman spectra specific for talc in unstained tissue samples (pleural tissue following talc pleurodesis and ovarian tissue following long-term perineal talc exposure). Raman microscopy is sufficiently sensitive and compositionally selective to identify particles as small as one micron in diameter. Among commonly used coverslip mounting media, Cytoseal 60 is recommended; Permount was unacceptable due to intense background interference. Raman spectra have been catalogued for thousands of substances, which suggests that this approach is likely to be successful in identifying other particles of interest in tissues, potentially making Raman microscopy a powerful new tool in pathology.

Flightfax: Army Aviation Risk-Management Information. Volume 28, Number 3, March 2000. Message from the Chief of Staff

DTIC Science & Technology

2000-03-01

Saturday nights carnauba wax , mineral oil, lanolin, up your life. Use only the Army talc, and colorants, supplied version for aircrew duties...ceresin wax , caster based face paint you might be Two-lane rural roads wax , mineral oil, talc, and pigments. tempted to pick up from local Time: ( NSN

Manganese-rich red tourmaline from the Fowler talc belt, New York.

USGS Publications Warehouse

Ayuso, R.A.; Brown, C. Erwin

1984-01-01

Red uvite containing up to 4.34 wt.% MnO is found in the Arnold talc mine near Fowler, New York, USA. Microprobe analyses give a composition of 51% uvite in the uvite-dravite series. Associated minerals in this manganiferous metamorphic assemblage (possibly an evaporite) are manganese-rich tremolite (hexagonite) braunite and quartz.-R.A.G.

A high-temperature hydrothermal deposit on the seabed at a Gulf of California spreading center ( Guaymas Basin).

USGS Publications Warehouse

Lonsdale, P.F.; Bischoff, J.L.; Burns, V.M.; Kastner, M.; Sweeney, R.E.

1980-01-01

A submersible dive on a turbidite-covered spreading axis in Guaymas Basin photographed and sampled extensive terraces and ledges of talc. The rock contains siliceous microfossils, smectite, and euhedral pyrrhotite as well as rather pure iron-rich talc. S and O isotopes indicate precipitation around a hydrothermal vent, at about 2800C. - Authors

Studying the effects of nucleating agents on texture modification of puffed corn-fish snack.

PubMed

Shahmohammadi, Hamid Reza; Bakar, Jamilah; Rahman, Russly Abdul; Adzhan, Noranizan Mohd

2014-02-01

To improve textural attributes of puffed corn-fish snack, the effects of 1%, 1.5%, and 2% of calcium carbonate, magnesium silicate (talc), sodium bicarbonate as well as 5% and 10% of wheat bran (as the nucleating materials) on textural attributes were studied. Sensory evaluation, bulk density, expansion ratio, maximum force, and count peaks were measured using the Kramer test. The results showed that all of the additives except bran significantly enhanced the texture. Among them, talc at 0.5% was the best to enhance the density and expansion ratio. Effects of using 0.5% talc on puffed corn-fish snack microstructure were studied using scanning electron microscopy. The average cell diameter of 109 ± 48 μm and cell numbers per square centimeter of 67.4 for talc-treated products were obtained, while for nontalc-treated extrudates, average cell diameter of 798 ± 361 μm and cell numbers per square centimeter of 13.9 were found. Incorporation of 0.5% w/w of magnesium silicate reduced (7-fold) the average cell diameter while increased (4-fold) the cell number. © 2014 Institute of Food Technologists®

Kulkeite, a new metamorphic phyllosilicate mineral: Ordered 1∶1 chlorite/talc mixed-layer

NASA Astrophysics Data System (ADS)

Schreyer, W.; Medenbach, O.; Abraham, K.; Gebert, W.; Müller, W. F.

1982-09-01

Kulkeite occurs as platy, colorless, porphyroblastic, single crystals up to 2 mm in size in a low-grade dolomite rock associated with a Triassic meta-evaporite series at Derrag, Tell Atlas, Algeria, It is associated with sodian aluminian talc, unusual chlorite polytypes, and both K and Na phlogopite. Kulkeite is optically biaxial, negative, n x=1.552, n y=1.5605, n z=1.5610, 2Vz=24° (obs.). Based on microprobe analysis the empirical formula is (Na0.38K0.01Ca0.01)(Mg8.02Al0.99)[Al1.43Si6.57O20](OH)10 with some variation in Na, Si, and tetrahedral Al. The crystals are monoclinic with a=5.319(1), b=9.195(2), c=23.897(10) Å, β=97° 1(3)'; Z=2; the calculated density is 2.70 g cm-3. The four strongest lines in the X-ray powder pattern are (d, I, hkl): 7.90, 100, 003; 1.533, 100, 060; 7.42, 80, 002; 3.38, 80, 007; the 001 reflection with 23.7 Å has intensity 10. Transmission electron microscopy confirms the nature of a regular 1∶1 mixed-layer, which consists of 14 Å chlorite (clinochlore) sheets alternating with sheets of one-layer (9.5 Å) talc characterized by the lattice substitution NaAl→Si just as in the talc occurring as a discrete mineral co-existing with kulkeite. Kulkeite is intergrown with lamellae of clinochlore that represent two-layer and five-layer (70 Å) polytypes with optical birefringence exceeding the normal value for clinochlore by a factor of 3. The origin of kulkeite is due to low-grade metamorphism with temperatures probably not exceeding 400° C. As the clinochlore lamellae and sodian aluminian talc are found in mutual contact, kulkeite seems to represent a metastable mineral at least during the latest phase of metamorphism. However, at an earlier stage, prior to clinochlore formation, kulkeite might have been stable, and the incorporation of Na and Al into its talc component could indeed be the decisive factor for the formation of the mixed-layer.

Cost-effectiveness of indwelling pleural catheter compared with talc in malignant pleural effusion.

PubMed

Olfert, Jordan A P; Penz, Erika D; Manns, Braden J; Mishra, Eleanor K; Davies, Helen E; Miller, Robert F; Luengo-Fernandez, Ramon; Gao, Song; Rahman, Najib M

2017-05-01

Malignant pleural effusion is associated with morbidity and mortality. A randomized controlled trial previously compared clinical outcomes and resource use with indwelling pleural catheter (IPC) and talc pleurodesis in this population. Using unpublished quality of life data, we estimate the cost-effectiveness of IPC compared with talc pleurodesis. Healthcare utilization and costs were captured during the trial. Utility weights produced by the EuroQol Group five-dimensional three-level questionnaire and survival were used to determine quality-adjusted life-years (QALYs) gained. The incremental cost-effectiveness ratio (ICER) was calculated over the 1-year trial period. Sensitivity analysis used patient survival data and modelled additional nursing time required per week for catheter drainage. Utility scores, cost and QALYs gained did not differ significantly between groups. The ICER for IPC compared with talc was favorable at $US10 870 per QALY gained. IPC was less costly with a probability exceeding 95% of being cost-effective when survival was <14 weeks, and was more costly when 2-h nursing time per week was assumed for catheter drainage. IPC is cost-effective when compared with talc, although substantial uncertainty exists around this estimate. IPC appears most cost-effective in patients with limited survival. If significant nursing time is required for catheter drainage, IPC becomes less likely to be cost-effective. Either therapy may be considered as a first-line option in treating malignant pleural effusion in patients without history of prior pleurodesis, with consideration for patient survival, support and preferences. © 2016 The Authors. Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.

Dehydration kinetics of talc at 1 bar

NASA Technical Reports Server (NTRS)

Ganguly, J.; Bose, K.

1991-01-01

Experimental results on the dehydration kinetics of talc, which is likely to be a major potential resource for water and hydrogen in carbonaceous chondrites, is presented. The rate of dehydration of an essentially pure Mg-end member natural talc, (Mg(.99)Fe(.01))3Si4O10(OH)2, was studied by measuring in situ weight change under isothermal condition at 1 bar as a function of time in the temperature range 775 to 985 C. The grain size of the starting material was 0.7 to 1 micron. It was found that the data up to 50 to 60 percent dehydration can be fitted by an equation of the form alpha = exp(-Kt(exp n)), where alpha is the weight fraction of talc remaining, K is a rate constant and n is a numerical constant for a given temperature. For any set of isothermal data, there is a major change in the value of n for larger dehydration. For up to approximately 50 percent dehydration, all rate constants can be described by an Arrheniun relation with an activation energy of 432 (+/- 30) kJ/mol; n has a nearly constant value of 0.54 between 775 and 875 C, but increases almost linearly according to n = -10.77 + 0.012T C at T greater than or equal to 875 C.

Surface energy of talc and chlorite: Comparison between electronegativity calculation and immersion results.

PubMed

Douillard, Jean-Marc; Salles, Fabrice; Henry, Marc; Malandrini, Harold; Clauss, Frédéric

2007-01-15

The surface energies of talc and chlorite is computed using a simple model, which uses the calculation of the electrostatic energy of the crystal. It is necessary to calculate the atomic charges. We have chosen to follow Henry's model of determination of partial charges using scales of electronegativity and hardness. The results are in correct agreement with a determination of the surface energy obtained from an analysis of the heat of immersion data. Both results indicate that the surface energy of talc is lower than the surface energy of chlorite, in agreement with observed behavior of wettability. The influence of Al and Fe on this phenomenon is discussed. Surface energy of this type of solids seems to depend more strongly on the geometry of the crystal than on the type of atoms pointing out of the surface; i.e., the surface energy depends more on the physics of the system than on its chemistry.

Structure development in melt processing isotactic polypropylene, polypropylene blends/compounds and dynamically vulcanized polyolefin TPEs

NASA Astrophysics Data System (ADS)

Yu, Yishan

The influence of various fillers, nucleating agents and ethylene propylene diene terpolymer (EPDM) additive on crystalline modification (alpha-, beta- and smectic forms) and crystalline orientation of polypropylene in die extrudates, melt spun filaments, thick rods, blow molded bottles and injection molded parts of isotactic polypropylene (PP), its blends/compounds and dynamically vulcanized polypropylene thermoplastic elastomers (TPEs) were experimentally studied under a range of cooling and processing conditions. The phenomena of crystallization, polymorphism and orientation in processing of both thin and thick samples (filaments, rods, bottles and injection molded parts) were simulated through transport laws incorporating polymer crystallization kinetics. Continuous cooling transformation (CCT) curves for the various material systems investigated were developed under quiescent and uniaxial stress conditions. We applied experimental data on polymorphism of thin sections to predict crystalline structure variation in thick parts. The predictions were consistent with experiments. For filaments, the polypropylene crystalline orientation-spinline stress relationship is generally similar for the neat PP, blends/compounds and TPEs. However, the blends and TPEs have much lower birefringence apparently due to a lack of orientation in the rubber phase. It was shown that the polypropylene contribution to the birefringence for the neat PP and its blends is the same at the same spinline stress. For bottles, the inflation pressures used have little effect on orientation of either polypropylene crystals or disc-shaped talc filler. The talc discs are highly oriented parallel to the bottle surface. For the bottles without talc, the orientation of polypropylene crystallographic axes are low. The polypropylene crystallographic b-axes in the talc filled bottles are more highly oriented. For injection molded parts, it was found that a low orientation layer exists between the part surface and an intermediate highly oriented layer in the parts of neat PP and its blends/compounds. The thickness of this layer increases as the injection pressure decreases. This layer was not formed in the TPE parts. This would seem to be associated with the TPEs exhibiting a yield stress in shear flow and not exhibiting fountain flow in mold filling. For all parts studied, the orientation characteristics of polypropylene crystallographic axes in the highly oriented layer are similar from sample to sample. The strong orientation of the c-axis parallel to the machine direction and the b-axis perpendicular to the machine direction are observed in the highly oriented layer. The talc discs in both the highly oriented layer and the intermediate position are highly oriented parallel to the part face due to melt flow. At intermediate position in the talc-filled parts, the polypropylene crystallographic (040) planes prefer to align themselves parallel to the part surface but are not so well oriented when the talc is absent.

Variable Seawater-Peridotite Interactions - First Insights From ODP Leg 209, MAR 15° N

NASA Astrophysics Data System (ADS)

Bach, W.; Garrido, C. J.; Harvey, J.; Paulick, H.; Rosner, M.; Odp Leg 193 Shipboard Science Party

2003-12-01

Serpentinization of peridotites at slow-spreading mid-ocean ridges has important consequences for the rheology of the oceanic lithosphere, geochemical budgets of the oceans, and microbial processes within, at, and above the seafloor. ODP Leg 209 recovered peridotites that show a remarkable variability of hydrothermal alteration reactions and intensities, including talc-tremolite alteration of pyroxenes associated with incipient serpentinization of olivine, complete alteration of peridotites to serpentine and magnetite followed by the destruction of magnetite and replacement of serpentine by talc, variable degrees of serpentine-brucite alteration, and replacement of brucite by iowaite. These rocks provide a unique opportunity to calibrate our observations against recent results from experimental/theoretical geochemical studies and further our understanding of serpentinization and its role in tectonic accretion and microbial colonization of oceanic lithosphere at slow and ultraslow spreading ridges. We propose that at temperatures above 250° C, pyroxenes react to form serpentine, talc, and tremolite, releasing Ca, Si, H2, and acidity to the reacting fluids that may cause rodingitization in adjacent gabbro bodies. Overall however, rodingites are rare, which may reflect the depleted nature of the mantle protoliths. In the absence of pyroxenes (in dunites) - or at temperatures below 250° C, where pyroxenes react very slowly - the fluids do not become enriched in Ca and Si and serpentine, magnetite, and brucite will form. Many serpentinites lack brucite, tremolite, and talc, because changes in fluid pH and silica activity of the interacting fluids, following the exhaustion of either olivine or pyroxene, caused reaction of these phases to serpentine. Extensive talc alteration of serpentinites and gabbros is usually observed at the intrusive contacts, but large-scale silica metasomatism (or Mg-loss) must be invoked to explain the overall abundance of talc at Site 1268. Significant pyrite/marcasite/hematite veining at Site 1268 indicates fairly oxidizing conditions consistent with the presence of sulfate in the interacting fluids. The first discovery of iowaite in mid-ocean ridge serpentinites (at Site 1272) and the abundant carbonate/Fe-oxyhydroxide alteration, locally extending down to 90 meters below seafloor, indicate that water-rock reactions continue at low temperatures and under strongly oxidizing conditions. Pore fluids from nontronite-bearing serpentine muds in fault gouges may provide information about the nature of these late-stage circulating fluids and potential microbial activity.

Evolution of carboxymethyl cellulose layer morphology on hydrophobic mineral surfaces: variation of polymer concentration and ionic strength.

PubMed

Beaussart, Audrey; Mierczynska-Vasilev, Agnieszka; Beattie, David A

2010-06-15

The adsorption of carboxymethyl cellulose (CMC) on the basal planes of talc and molybdenite has been studied using in situ atomic force microscope (AFM) imaging. These experiments were partnered with quantitative adsorption isotherm determinations on particulate samples. The isotherms revealed a clear increase of the CMC adsorbed amount upon increasing the solution ionic strength for adsorption on both minerals. In addition, the shapes of the isotherms changed in response to the change in the electrolyte concentration, with CMC on talc displaying stepped (10(-3) M KCl), Langmuir (10(-2) M KCl), then Freundlich isotherm shapes (10(-1) M KCl), and CMC on molybdenite displaying stepped (10(-3) M KCl), Freundlich (10(-2) M KCl), then Langmuir isotherm shapes (10(-1) M KCl). AFM imaging of the polymer layer on the mineral surfaces with varying solution conditions mirrored and confirmed the conclusions from the isotherms: as the polymer solution concentration increased, coverage on the basal plane increased; as the ionic strength increased, coverage on the basal plane increased and the morphology of the layer changed from isolated well-distributed polymer domains to extensive adsorption and formation of dense, uneven polymer domains/features. In addition, comparison of the talc and molybdenite datasets points toward the presence of different binding mechanisms for CMC adsorption on the talc and molybdenite basal plane surfaces. 2010 Elsevier Inc. All rights reserved.

Bacillus subtilis based-formulation for the control of postbloom fruit drop of citrus.

PubMed

Klein, Mariana Nadjara; da Silva, Aline Caroline; Kupper, Katia Cristina

2016-12-01

Postbloom fruit drop (PFD) caused by Colletotrichum acutatum affects flowers and causes early fruit drop in all commercial varieties of citrus. Biological control with the isolate ACB-69 of Bacillus subtilis has been considered as a potential method for controlling this disease. This study aimed to develop and optimize a B. subtilis based-formulation with a potential for large-scale applications and evaluate its effect on C. acutatum in vitro and in vivo. Bacillus subtilis based-formulations were developed using different carrier materials, and their ability to control PFD was evaluated. The results of the assays led to the selection of the B. subtilis based-formulation with talc + urea (0.02 %) and talc + ammonium molybdate (1 mM), which inhibited mycelial growth and germination of C. acutatum. Studies with detached citrus flowers showed that the formulations were effective in controlling the pathogen. In field conditions, talc + urea (0.02 %) provided 73 % asymptomatic citrus flowers and 56 % of the average number of effective fruit (ANEF), equating with fungicide treatment. On the contrary, non-treated trees had 8.8 % of asymptomatic citrus flowers and 0.83 % ANEF. The results suggest that B. subtilis based-formulations with talc as the carrier supplemented with a nitrogen source had a high potential for PFD control.

Discovery of hydrothermally active and extinct talc mounds on the Mid-Cayman Rise

NASA Astrophysics Data System (ADS)

Hodgkinson, M.; Murton, B. J.; Roberts, S.

2013-12-01

Since 1977, hydrothermal vents have been the subject of intense scientific interest due to their role in cooling the oceanic crust and global geochemical cycles. Until now, two types of hydrothermal system have been identified: one, driven by magmatic heat extruding ';black smoker' fluids; and another, involving serpentinisation of ultramafic rocks and the precipitation of carbonate/brucite chimneys. Here, we present details of a new, off-axis type of hydrothermal system consisting of mounds of predominately botryoidal talc (a magnesium-silicate) with accessory silica and copper sulphides, and chimneys exhaling fluids of moderate temperature and pH. Discovered on the Mid-Cayman Rise (MCR) in 2010, the Von Damm Vent Field (VDVF) features a NNW-ESE-trending line of four overlapping cones, the largest of which is 75 m high by 150 m in diameter. The VDVF is hosted in the gabbroic footwall of the Mount Dent Oceanic Core Complex (MDOCC), which includes serpentinised peridotite at depth. The largest cone vents clear fluids from two main orifices at its summit, with primary temperatures of 215°C. Elsewhere, both focussed and diffuse flow areas emit fluids with temperatures of up to 150°C. The surrounding ~1 m thick pelagic sediment contains abundant pockmarks that emit methane-rich fluids at temperatures of less than 10°C. During the return to the MCR in early 2013, several other talc mounds were discovered within a kilometre of the active VDVF. These inactive mounds also comprise an assemblage of botryoidal talc, silica, disseminated sulphides (including chalcopyrite) and sulphates. One of these mounds (Mystic Mount) is double the volume of the active VDVF. The unique dominance of talc as the major mineral forming the hydrothermal structures indicates unusual vent fluid compositions that are able to carry both copper (at high-temperatures) and precipitate magnesium silicate. Thermodynamic modelling indicates that talc precipitates on mixing a moderately acidic, silica rich fluid (e.g. the primary VDVF fluids) with only 2% of seawater. At lower pH (e.g. typical ';black smoker' fluids), the ratio jumps to over 90% while at high pH (e.g. ';Lost City' fluids) brucite and carbonate dominate. Estimates using recently measured vent temperatures and fluid fluxes indicate a heat flux of ~800 MW for the active VDVF. Assuming the primary vent fluid has remained largely unchanged, the VDVF could have grown in under 1000 years and Mystic Mount in ~2000 years. Both the hydrothermal mounds and faults in the surrounding gabbro share a NNW-ESE orientation that is consistent with a brittle structural control imposed by the flexural curvature of the MDOCC in response to the uplift of the lower oceanic crust along a low-angle detachment fault. We propose that these flexural faults provide pathways for fluids to ingress deep into the MDOCC where they react with both mafic rocks (producing high-temperature, low pH, sulphide and copper-bearing fluids), peridotites and carbonates (increasing the pH) resulting in a moderate pH, silica-rich fluid that precipitates talc on mixing with seawater. The presence of further, inactive, talc mounds within 1 km of the VDVF indicates hydrothermal activity on OCCs has been widespread and represents a significant but hitherto overlooked mechanism of crustal heat loss and chemical interaction with the ocean at slow-spreading ridges.

Assessment of Plant-Probiotic Performance of Novel Endophytic Bacillus sp. in Talc-Based Formulation.

PubMed

Basheer, Jasim; Ravi, Aswani; Mathew, Jyothis; Krishnankutty, Radhakrishnan Edayileveettil

2018-01-25

Endophytic bacteria are considered to have a plethora of plant growth promoting and anti-phytopathogenic traits to live within the plants. Hence, they have immense promises for plant probiotic development. In the current study, plant probiotic endophytic Bacillus sp. CaB5 which has been previously isolated from Capsicum annuum was investigated for its performance in talc-based formulation. For this, CaB5 was made into formulation with sterile talc, calcium carbonate, and carboxymethyl cellulose. The viability analysis of the formulation by standard plate count and fluorescence methods has confirmed the stable microbial count up to 45 days. Plant probiotic performance of the prepared formulation was analyzed on cowpea (Vigna unguiculata) and lady's finger (Abelmoschus esculentus). The results showed the formulation treatment to have enhancement effect on seed germination as well as plant growth in both selected plants. The results highlight the potential of CaB5-based formulation for field application to enhance growth of economically important plants.

Rapid Adsorption of Heavy Metals by Fe3O4/Talc Nanocomposite and Optimization Study Using Response Surface Methodology

PubMed Central

Kalantari, Katayoon; Ahmad, Mansor B.; Masoumi, Hamid Reza Fard; Shameli, Kamyar; Basri, Mahiran; Khandanlou, Roshanak

2014-01-01

Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe3O4/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions. PMID:25050784

Rapid adsorption of heavy metals by Fe3O4/talc nanocomposite and optimization study using response surface methodology.

PubMed

Kalantari, Katayoon; Ahmad, Mansor B; Masoumi, Hamid Reza Fard; Shameli, Kamyar; Basri, Mahiran; Khandanlou, Roshanak

2014-07-21

Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe3O4/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions.

Chromian spinels in highly altered ultramafic rocks from the Sartohay ophiolitic mélange, Xinjiang, NW China

NASA Astrophysics Data System (ADS)

Qiu, Tian; Zhu, Yongfeng

2018-06-01

The Sartohay ophiolitic mélange is located in western Junggar (Xinjiang province, NW China), which is a major component of the core part of the Central Asian Orogenic Belt (CAOB). Chromian spinels in serpentinite, talc schist, carbonate-talc schist and listwaenite in Sartohay ophiolitic mélange retain primary compositions with Cr# of 0.39-0.65, Mg# = 0.48-0.67, and Fe3+# < 0.08. Chromian spinels in deformed listwaenite were initially transformed into Fe2+-rich chromite during shearing deformation followed by Fe3+-rich chromite at shallow levels. The Cr# and Fe3+# of Fe2+-rich chromite (Cr# = 0.59-0.86, Fe3+# = 0.01-0.12, Mg# = 0.35-0.61) and Fe3+-rich chromite (Cr# = 0.85-1.00, Fe3+# = 0.17-0.38, Mg# < 0.29) increase with decrease of Mg#. We propose a model to illustrate the evolution of chromian spinels in highly altered ultramafic rocks from the Sartohay ophiolitic mélange. Chromian spinels in serpentinite and talc schist were rimmed by Cr-magnetite, which was dissolved completely during transformation from serpentinite/talc schist to listwaenite. Chromian spinels were then transformed into Fe2+-rich chromite in shear zones, which characterized by high fluid/rock ratios. This Fe2+-rich chromite and/or chromian spinels could then be transformed into Fe3+-rich chromite in oxidizing conditions at shallow levels.

Concentration of seeded simian rotavirus SA-11 from potable waters by using talc-celite layers and hydroextraction.

PubMed

Ramia, S; Sattar, S A

1980-03-01

There is mounting evidence for the waterborne transmission of diarrhea caused by rotaviruses. As a result, proper techniques are required for their recovery from samples of incriminated water. The combined efficiency of the talc-Celite technique and polyethylene glycol 6000 hydroextraction was, therefore, tested for this purpose, using Simian rotavirus SA-11 and MA-104 cells. Conditioning of the dechlorinated tap water samples was carried out by pH adjustment to 6.0 and the addition of Earle balanced salt solution to a final concentration of 1:100. Passage of a 1-liter volume of such a conditioned sample through a layer containing a mixture of talc (300 mg) and Celite 503 (100 mg) led to the adsorption of nearly 93% of the added SA-11 plaque-forming units. For the recovery of the layer-adsorbed virus, 3% beef extract and 1x tryptose phosphate broth were found to be superior to a variety of other eluents tested. When we tested 100-liter sample volumes, layers containing 1.2 g of talc and 0.4 g of Celite were employed. Virus elution was carried out with 100 ml of tryptose phosphate broth. The eluate was concentrated 10-fold by overnight (4 degrees C) hydroextraction with polyethylene glycol. With a total input virus of 7.0 x 10(5) and 1.4 x 10(2) plaque-forming units, the recoveries were about 71 and 59%, respectively.

Chemical pleurodesis for malignant pleural effusions.

PubMed

Walker-Renard, P B; Vaughan, L M; Sahn, S A

1994-01-01

To provide information about available agents for chemical pleurodesis. A MEDLINE search (1966 to October 1992) was conducted using the terms malignant pleural effusion and pleurodesis. All articles containing references to patients with recurrent, symptomatic, malignant pleural effusions treated with chemical pleurodesis were selected and reviewed for pleurodesis regimen, number of patients treated, success rate (complete response), and adverse effects. The agents studied included doxycycline, minocycline, tetracycline, bleomycin, cisplatin, doxorubicin, etoposide, fluorouracil, interferon-beta, mitomycin-c, Corynebacterium parvum, methylprednisolone, and talc. Independent extraction by three observers. Studies including a total of 1168 patients with malignant pleural effusions were reviewed for efficacy of the pleurodesis agent and studies including 1140 patients were reviewed for toxicity. Chemical pleurodesis produced a complete response in 752 (64%) of 1168 patients. The success rate of the pleurodesis agents varied from 0% with etoposide to 93% with talc. Corynebacterium parvum, the tetracyclines, and bleomycin had success rates of 76%, 67%, and 54%, respectively. The most commonly reported adverse effects were pain (265 of 1140, 23%) and fever (220 of 1140, 19%). Doxycycline and minocycline, with success rates of 72% and 86%, respectively, appear to be effective tetracycline-replacement agents in the few patients studied. Talc appears to be the most effective and least expensive agent; however, insufflation has the disadvantages of the expense of thoracoscopy and the usual need for general anesthesia. Bleomycin appears to be less effective than talc and the tetracyclines and is substantially more expensive.

An Examination of Issues Related to U.S. Lake Erie Natural Gas Development.

DTIC Science & Technology

1978-09-01

37 pg/mL 27 pg/mL 27 pg/mL 27 pg/mL detergent Wac-8 Talc & guar Non-toxic to 10,000 pg/mL in 24 hours gum Wac-10 Talc, silica Non-toxic to 10,000 ug...mL in 24 hours guar gum Fr-10 High molecu- Bioassay Method not applicable lar weight synthetic Fr-19 Polymer Bioassay Method not applicable aData from...Adeorption None Activated carbon. Activated carbon Activated carbon Activated carbon Activated carbon powdered Filtration Sandb Activated carbon. Sand Sand

Column bioleaching of low-grade mining ore containing high level of smithsonite, talc, sphaerocobaltite and azurite.

PubMed

Ilyas, Sadia; Chi, Ruan; Bhatti, H N; Bhatti, I A; Ghauri, M A

2012-03-01

Present work describes the bioleaching potential of metals from low-grade mining ore containing smithsonite, sphaerocobaltite, azurite and talc as main gangue minerals with adapted consortium of Sulfobacillus thermosulfidooxidans strain-RDB and Thermoplasma acidophilum. Bioleaching potential improved markedly by added energy source, acid preleaching and adaptation of microbial consortium with mixed metal ions. During whole leaching period including acid preleaching stage of 960 h and bioleaching stage of 212 days about 76% Co, 70% Zn, 84% Cu, 72% Ni and 63% Fe leached out.

Si-metasomatism in serpentinized peridotite: The effects of talc-alteration on strontium and boron isotopes in abyssal serpentinites from Hole 1268a, ODP Leg 209

NASA Astrophysics Data System (ADS)

Harvey, Jason; Savov, Ivan P.; Agostini, Samuele; Cliff, Robert A.; Walshaw, Richard

2014-02-01

Ultramafic rocks recovered from Hole 1268a, Ocean Drilling Program Leg 209, to the south of the 15°20‧N Fracture Zone on the Mid-Atlantic ridge have experienced a complex history of melt depletion and subsequent interaction with a series of fluids under varying temperature and pH conditions. After intense melt depletion, varying degrees of serpentinization at 100-200 °C took place, initially under seawater-like pH conditions. Subsequently, interaction with a higher temperature (300-350 °C) fluid with low (4-5) pH and low MgO/SiO2 resulted in the heterogeneous alteration of these serpentinites to talc-bearing ultramafic lithologies. The proximity of the currently active, high temperature Logatchev hydrothermal field, located on the opposite flank of the Mid-Atlantic ridge, suggests that unlike more distal localities sampled during ODP Leg 209, Hole 1268a has experienced Si-metasomatism (i.e. talc-alteration) by a Logatchev-like hydrothermal fluid. Serpentinite strontium isotope ratios were not materially shifted by interaction with the subsequent high-T fluid, despite the likelihood that this fluid had locally interacted with mid-ocean ridge gabbro. 87Sr/86Sr in the ultramafic lithologies of Hole 1268a are close to that of seawater (c.0.709) and even acid leached serpentinites retain 87Sr/86Sr in excess of 0.707, indistinguishable from Logatchev hydrothermal fluid. On the other hand, boron isotope ratios appear to have been shifted from seawater-like values in the serpentinites (δ11B = c.+40‰) to much lighter values in talc-altered serpentinites (δ11B = +9 to +20‰). This is likely a consequence of the effects of changing ambient pH and temperature during the mineralogical transition from serpentine to talc. Heterogeneous boron isotope systematics have consequences for the composition of ultramafic portions of the lithosphere returned to the convecting mantle by subduction. Inhomogeneities in δ11B, [B] and mineralogy introduce significant uncertainties in the prediction of the composition of slab fluids released during the early- to mid-stages of subduction.

The effect of carbon-rich fluid alteration on the mechanical and physical properties of ultramafic rocks from Linnejavrre, Norway

NASA Astrophysics Data System (ADS)

Lisabeth, H. P.; Zhu, W.

2016-12-01

Carbon dioxide interacts with mafic and ultramafic rocks on the ocean floor at fracture zones and detachment faults, and within ophiolite complexes. Steatized olivine-pyroxene or serpentinite rocks become talc-carbonate rocks, i.e., soapstones. If the fluids are extremely carbon-rich, the process can continue to completion, binding all the magnesium from olivine and pyroxene in magnesium carbonate, resulting in magnesite-quartz rocks known as listvenites. The structural, mechanical and mineralogical characteristics of these rocks can be long-lived and affect later tectonic deformation over the course of the supercontinent cycle, influencing the obduction of ophiolites and possibly the initiation of subduction. To ascertain the changes in physical and geomechanical characteristics of these rocks as they undergo carbonic alteration, we measure ultrasonic velocity, electrical resistivity and shear strength in a series of laboratory tests on samples collected from northern Norway, where the Linnajavrre Ophiolite contains representative samples of serpentinite, soapstone and listvenite. We discover that the rocks tend to become denser, more porous, weaker, and more electrically and acoustically impeditive as carbonation proceeds. Samples fail by highly localized brittle faulting with little dilatancy. Shear strength appears to correlate with talc abundance, with a steep drop-off from 5 to 20% talc. Deformed samples are examined under petrographic microscope to explore deformation micromechanisms. Our data suggest that the weakening observed in soapstones and listvenites compared to serpentinites is attributed to interconnected talc grains. Such carbonic alteration of oceanic serpentinites may help facilitate oceanic spreading, particularly along slow and ultraslow segments of mid-ocean ridges.

Can EGFR-Tyrosine Kinase Inhibitors (TKI) Alone Without Talc Pleurodesis Prevent Recurrence of Malignant Pleural Effusion (MPE) in Lung Adenocarcinoma.

PubMed

Verma, Akash; Chopra, Akhil; Lee, Yeo W; Bharwani, Lavina D; Asmat, Atasha B; Aneez, Dokeu B A; Akbar, Fazuludeen A; Lim, Albert Y H; Chotirmall, Sanjay H; Abisheganaden, John

2016-01-01

Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors (EGFR-TKIs) are effective against lung adenocarcinoma. However, limited data is available assessing the effectiveness of EGFR-TKI use in preventing re-accumulation of MPE. To our knowledge, there is no literature on comparison of talc pleurodesis with EGFR-TKIs alone on re-accumulation of MPE in Asian population. We investigated if EGFR-TKI therapy for advanced lung adenocarcinoma with malignant pleural effusion (MPE) is also successful in preventing pleural fluid re-accumulation following initial drainage. An observational cohort study of patients with lung adenocarcinoma and MPE in the year 2012 was conducted. 70 patients presented with MPE from lung adenocarcinoma. Fifty six underwent EGFR mutation testing of which 39 (69.6%) had activating EGFR mutation and 34 (87.1%) received TKI. 20 were managed by pleural fluid drainage only whereas 14 underwent talc pleurodesis following pleural fluid drainage. Time taken for the pleural effusion to re-accumulate in those with and without pleurodesis was 9.9 vs. 11.7 months, p=0.59 respectively. More patients (n=10, 25.6%) with activating EGFR mutation presented with complete opacification (white-out) of the hemithorax compared to none without activating EGFR mutation (p=0.02). In TKI eligible patients, early talc pleurodesis may not confer additional benefit in preventing re-accumulation of pleural effusion and may be reserved for non-adenocarcinoma histology, or EGFR negative adenocarcinoma. Complete opacification of the hemithorax on presentation may serve as an early radiographic signal of positive EGFR mutation status.

Influence of electron beam irradiation on mechanical and thermal properties of polypropylene/polyamide blend

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, Shigeya, E-mail: shi-nakamura@hitachi-chem.co.jp; Tokumitsu, Katsuhisa

The effects of electron beam irradiation on the mechanical and thermal properties of polypropylene (PP) and polyamide6 (PA6) blends-with talc 20 wt% as filler, SEBS-g-MAH as compatibilizer, and triallyl isocyanurate as crosslinking agent-were investigated. Although the tensile and flexural moduli and strengths of the PP/PA6 blends with talc, SEBS-g-MAH, and TAIC could be increased by the application of electron beam irradiation, the impact strength was decreased. Ddifferential scanning calorimetryer measurements showed that the melting temperatures of all PP/PA6 blends were decreased with increases in the electron beam irradiationdose. From dynamic mechanical analyzer results, a storage modulus curve in the plateaumore » region was observed only in the PP/PA6 blends with talc, SEBS-g-MAH, and TAIC; the storage modulus increased with increasing electron beam irradiation dose, indicating that the three-dimensional network developed gradually in the more amorphous PA6. As a result, the most significant improvement observed in heat distortion tests under high load (1.8 MPa) occurred at 200 kGy.« less

Efficacy of short-term versus long-term chest tube drainage following talc slurry pleurodesis in patients with malignant pleural effusions: a randomised trial.

PubMed

Goodman, Anna; Davies, Christopher W H

2006-10-01

Talc pleurodesis is commonly used in the palliative treatment of malignant pleural effusions but the shortest and most effective regime has not been determined. In particular, it is not clear when the intercostal drain should be removed following the insertion of sclerosant. We conducted a single-centre, randomised, open trial of drain removal at 24 h versus 72 h following talc slurry pleurodesis. The primary outcome measure was success of pleurodesis (no recurrence of effusion on chest radiograph at 1-month follow-up) and secondary outcome measures included length of hospital stay and mortality. We found no difference between recurrence of pleural effusion in those randomised to drain removal at 24 h and those randomised to drain removal at 72 h (p>0.5). However, length of stay was significantly reduced when the chest drain was removed at 24 h (4 days versus 8 days; p<0.01). Mortality did not differ between the two groups. We conclude that this shorter pleurodesis regime is safe and effective.

Removal of zearalenone toxin from synthetics gastric and body fluids using talc and diatomite: a batch kinetic study.

PubMed

Sprynskyy, Myroslav; Gadzała-Kopciuch, Renata; Nowak, Karolina; Buszewski, Bogusław

2012-06-01

Adsorption kinetics of zearalenone (ZEA) toxin from synthetic gastric fluid (SGF) and synthetic body fluid (SBF) by talc and diatomite was studied in the batch experiments. Chemical composition, morphology and structure of the used adsorbents were examined by scanning electron microscopy, FTIR spectroscopy and low-temperature nitrogen adsorption/desorption method. High performance liquid chromatography (HPLC) method was used for ZEA determining. The study results showed that ZEA is more effectively adsorbed on the talc (73% and 54% from SGF and SBF respectively). The efficiency on the diatomite was lower (53% and 42% from SGF and SBF respectively). The first order kinetics model was applied to describe the adsorption process. Rate of the ZEA adsorption from SGF is very rapid initially with about 95% of amount of the toxin adsorbed during first 5 min, while ZEA is adsorbed from SBF in two steps. The values of determined Gibbs free energy of adsorption (from -13 to -17 kJ/mol) indicated that adsorption of ZEA toxin by the both adsorbents are spontaneous and exothermic. Copyright © 2012 Elsevier B.V. All rights reserved.

A review of mortality associated with elongate mineral particle (EMP) exposure in occupational epidemiology studies of gold, talc, and taconite mining.

PubMed

Mandel, Jeffrey H; Alexander, Bruce H; Ramachandran, Gurumurthy

2016-12-01

Mining of gold, taconite, and talc may involve exposure to elongate mineral particles (EMP). The involved EMPs are typically non-asbestiform, include dimensions that regulatory definitions exclude, and have been less studied. A review of the literature was undertaken for this exposure and occupational epidemiological studies that occur in gold, talc, and taconite mining. Quantitative EMP exposure information in these industries is incomplete. However, there are consistent findings of pneumoconiosis in each of these types of mining. A recent case-control study suggests a possible association between this exposure and mesothelioma. Lung cancer is inconsistently reported in these industries and is an unlikely outcome of non-asbestiform EMP exposure. There is evidence of cardiovascular mortality excess across all of these types of mining. Non-malignant respiratory disease and cardiovascular mortality have been consistently increased in these industries. Further investigation, including additional insights for the role of non-asbestiform EMP, is warranted. Am. J. Ind. Med. 59:1047-1060, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Effect of an Indwelling Pleural Catheter vs Talc Pleurodesis on Hospitalization Days in Patients With Malignant Pleural Effusion

PubMed Central

Thomas, Rajesh; Fysh, Edward T. H.; Smith, Nicola A.; Lee, Pyng; Kwan, Benjamin C. H.; Yap, Elaine; Horwood, Fiona C.; Piccolo, Francesco; Lam, David C. L.; Garske, Luke A.; Shrestha, Ranjan; Kosky, Christopher; Read, Catherine A.; Murray, Kevin

2017-01-01

Importance Indwelling pleural catheter and talc pleurodesis are established treatments for malignant pleural effusions among patients with poor prognosis. Objective To determine whether indwelling pleural catheters are more effective than talc pleurodesis in reducing total hospitalization days in the remaining lifespan of patients with malignant pleural effusion. Design, Setting, and Participants This open-label, randomized clinical trial included participants recruited from 9 centers in Australia, New Zealand, Singapore, and Hong Kong between July 2012 and October 2014; they were followed up for 12 months (study end date: October 16, 2015). Patients (n = 146) with symptomatic malignant pleural effusion who had not undergone indwelling pleural catheter or pleurodesis treatment were included. Interventions Participants were randomized (1:1) to indwelling pleural catheter (n = 74) or talc pleurodesis (n = 72), minimized by malignancy (mesothelioma vs others) and trapped lung (vs not), and stratified by region (Australia vs Asia). Main Outcomes and Measures The primary end point was the total number of days spent in hospital from procedure to death or to 12 months. Secondary outcomes included further pleural interventions, patient-reported breathlessness, quality-of-life measures, and adverse events. Results Among the 146 patients who were randomized (median age, 70.5 years; 56.2% male), 2 withdrew before receiving the randomized intervention and were excluded. The indwelling pleural catheter group spent significantly fewer days in hospital than the pleurodesis group (median, 10.0 [interquartile range [IQR], 3-17] vs 12.0 [IQR, 7-21] days; P = .03; Hodges-Lehmann estimate of difference, 2.92 days; 95% CI, 0.43-5.84). The reduction was mainly in effusion-related hospitalization days (median, 1.0 [IQR, 1-3] day with the indwelling pleural catheter vs 4.0 (IQR, 3-6) days with pleurodesis; P < .001; Hodges-Lehmann estimate, 2.06 days; 95% CI, 1.53-2.58). Fewer patients randomized to indwelling pleural catheter required further ipsilateral invasive pleural drainages (4.1% vs 22.5%; difference, 18.4%; 95% CI, 7.7%-29.2%). There were no significant differences in improvements in breathlessness or quality of life offered by indwelling pleural catheter or talc pleurodesis. Adverse events were seen in 22 patients in the indwelling pleural catheter group (30 events) and 13 patients in the pleurodesis group (18 events). Results Among 146 randomized patients (median age, 70.5 years; 56.2% male), 2 were excluded. The indwelling pleural catheter group spent significantly fewer days in hospital than the pleurodesis group. The reduction was mainly in effusion-related hospitalization days. Fewer patients randomized to indwelling pleural catheter required further ipsilateral invasive pleural drainages. There were no significant between-group differences in improvements in breathlessness or quality of life. Adverse events occurred in both groups: 30 events in 22 catheter patients and 23 events in 13 talc pleurodesis patients. Indwelling Pleural Catheter(n = 73) Talc Pleurodesis(n = 71) Estimated Difference in Location or Proportions (95% CI) P Value Primary Outcome Total all-cause hospital stay, median (IQR), d 10 (3-17) 12 (7-21) 2.92 (0.43-5.84) .03 Secondary Outcomes Effusion-related hospital stay, median (IQR), d 1 (1-3) 4 (3-6) 2.06 (1.53-2.58) <.001 Further ipsilateral invasive pleural procedures required, No. (%) 3 (4) 16 (22) 0.18 (0.08-0.29) .001 Conclusions and Relevance Among patients with malignant pleural effusion, treatment with an indwelling pleural catheter vs talc pleurodesis resulted in fewer hospitalization days from treatment to death, but the magnitude of the difference is of uncertain clinical importance. These findings may help inform patient choice of management for pleural effusion. Trial Registration anzctr.org.au Identifier: ACTRN12611000567921 PMID:29164255

Pleurodesis for malignant pleural effusions.

PubMed

Shaw, P; Agarwal, R

2004-01-01

Approximately half of all patients with metastatic cancer develop a malignant pleural effusion which is likely to lead to a significant reduction in quality of life secondary to symptoms such as dyspnoea and cough. The aim of pleurodesis in these patients is to prevent re-accumulation of the effusion and thereby of symptoms, and avoid the need for repeated hospitalization for thoracocentesis. Numerous clinical studies have been performed to try to determine the optimal pleurodesis strategy, and synthesis of the available evidence should facilitate this. The aims of this review were to ascertain the optimal technique of pleurodesis in cases of malignant pleural effusion; to confirm the need for a sclerosant; and to clarify which, if any, of the sclerosants is the most effective. The Cochrane Central Register of Controlled Trials was searched for studies on 'pleurodesis'. Studies for inclusion were also identified from MEDLINE (1980 to June 2002) and EMBASE (1980 to May 2002). No language restriction was applied. RCTs of adults subjects undergoing pleurodesis for pleural effusion in the context of metastatic malignancy (or a malignant process leading to pleural effusion) were included. Two reviewers independently selected studies for inclusion in the review, and extracted data using a standard data collection form. Primary outcome measures sought were effectiveness of pleurodesis as defined by freedom from recurrence of effusions, and mortality after pleurodesis. Secondary outcomes were adverse events due to pleurodesis. Dichotomous data were meta-analysed using a fixed effect model and expressed as relative risk. The number-needed-to-treat (NNT) was calculated for pleurodesis efficacy. In addition, for adverse events, the overall percentage of patients across studies exhibiting a particular adverse effect such as fever, pain, or gastrointestinal symptoms was calculated. A total of 36 RCTs with 1499 subjects were eligible for meta-analysis. The use of sclerosants (mitozantrone, talc and tetracycline combined)compared with control (instillation of isotonic saline or equivalent pH isotonic saline or tube drainage alone) was associated with an increased efficacy of pleurodesis. The relative risk (RR) of non-recurrence of an effusion is 1.20 (95% CI 1.04 to 1.38) in favour of the use of sclerosants based on five studies with a total 228 subjects. Comparing different sclerosants, talc was found to be the most efficacious. The RR of effusion non-recurrence was 1.34 (95% CI 1.16 to 1.55) in favour of talc compared with bleomycin, tetracycline, mustine or tube drainage alone based on 10 studies comprising 308 subjects. This was not associated with increased mortality post pleurodesis. The RR of death was 1.19 (95% CI 0.08 to 1.77) for talc compared to bleomycin, tetracycline, mustine and tube drainage alone based on six studies of 186 subjects. Death was not reported in all studies and, when reported, was attributed to underlying disease, only one death being reported as procedure-related. In the comparison of thoracoscopic versus medical pleurodesis, thoracoscopic pleurodesis was found to be more effective. The RR of non-recurrence of effusion is 1.19 (95% CI 1.04 to 1.36) in favour of thoracoscopic pleurodesis compared with tube thoracostamy pleurodesis utilizing talc as sclerosant based on two studies with 112 subjects. Comparing thoracoscopic versus bedside instillation (with different sized chest tubes) of various sclerosants (tetracycline, bleomycin, talc or mustine) the RR of non-recurrence of effusion is 1.68 (95% CI 1.35 to 2.10) based on five studies with a total of 145 participants.Adverse events were not reported adequately to enable meta-analysis. The available evidence supports the need for chemical sclerosants for successful pleurodesis, the use of talc as the sclerosant of choice, and thoracoscopic pleurodesis as the preferred technique for pleurodesis based on efficacy. There was no evidence for an increase in mortality following talc pleurodesis.

Comparison Between 2D and 3D Simulations of Rate Dependent Friction Using DEM

NASA Astrophysics Data System (ADS)

Wang, C.; Elsworth, D.

2017-12-01

Rate-state dependent constitutive laws of frictional evolution have been successful in representing many of the first- and second- order components of earthquake rupture. Although this constitutive law has been successfully applied in numerical models, difficulty remains in efficient implementation of this constitutive law in computationally-expensive granular mechanics simulations using discrete element methods (DEM). This study introduces a novel approach in implementing a rate-dependent constitutive relation of contact friction into DEM. This is essentially an implementation of a slip-weakening constitutive law onto local particle contacts without sacrificing computational efficiency. This implementation allows the analysis of slip stability of simulated fault gouge materials. Velocity-stepping experiments are reported on both uniform and textured distributions of quartz and talc as 3D analogs of gouge mixtures. Distinct local slip stability parameters (a-b) are assigned to the quartz and talc, respectively. We separately vary talc content from 0 to 100% in the uniform mixtures and talc layer thickness from 1 to 20 particles in the textured mixtures. Applied shear displacements are cycled through velocities of 1μm/s and 10μm/s. Frictional evolution data are collected and compared to 2D simulation results. We show that dimensionality significantly impacts the evolution of friction. 3D simulation results are more representative of laboratory observed behavior and numerical noise is shown at a magnitude of 0.01 in terms of friction coefficient. Stability parameters (a-b) can be straightforwardly obtained from analyzing velocity steps, and are different from locally assigned (a-b) values. Sensitivity studies on normal stress, shear velocity, particle size, local (a-b) values, and characteristic slip distance (Dc) show that the implementation is sensitive to local (a-b) values and relations between (Dc) and particle size.

An evaluation of a positive youth development program for adolescents with chronic illness.

PubMed

Maslow, Gary; Adams, Cathleen; Willis, Matthew; Neukirch, Jodie; Herts, Kate; Froehlich, Wendy; Calleson, Diane; Rickerby, Michelle

2013-02-01

Youth with chronic illness often struggle transitioning to adulthood and adult medical care. This article examines the outcomes of a group mentoring program called The Adolescent Leadership Council (TALC) that brings together high school participants and college mentors, all with chronic illness. TALC uses a positive youth development (PYD) approach, emphasizing strong relationships between youth and adults in an environment where youth can learn important life skills and take a leadership role. A pre-/postprogram participant survey was conducted for high school participants using a loneliness scale and a transition readiness survey. An alumni survey was conducted with all high school and college mentor graduates to assess educational-, vocational-, and health care-related outcomes. Program records review and the alumni survey indicated that TALC was consistent with the PYD program model. Twenty high school students participated in the pre-/postprogram outcomes evaluation, which demonstrated a decrease in loneliness from 46 to 38.5 (p < .001) and an increase in health care self-advocacy from 3.8 to 4.2 (p < .001). Thirty-four alumni participated in the alumni survey. All high school and college mentor alumni had graduated from high school and college, respectively, and all were either currently in school or working. The majority of alumni were seeing adult providers for medical care. The TALC program applies the principles of PYD to support positive educational, vocational, and health care outcomes for youth with chronic illness. Program development using the PYD perspective is an important new approach for supporting adult development of youth with chronic illness. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Phyllosilicate weathering pathways in chlorite-talc bearing soil parent materials, D.R. Congo: early findings.

NASA Astrophysics Data System (ADS)

Dumon, Mathijs; Oostermeyer, Fran; Timmermans, Els; De Meulemeester, Aschwin; Mees, Florias; Van Driessche, Isabel; Erens, Hans; Bazirake Mujinya, Basile; Van Ranst, Eric

2015-04-01

The study of the formation and transformation of clay minerals is of the upmost importance to understand soil formation and to adjust land-use management to the land surface conditions. These clay minerals determine to a large extent the soil physical and chemical properties. It is commonly observed that over time the mineralogy of any parent material is transformed to a simple assemblage composed mostly of Al and Fe oxides and low-activity clays, e.g. kaolinite. This is especially obvious in the humid tropics, which have been protected from glacial erosion, allowing deep, highly weathered soils to form. Despite the abundant presence of kaolinite in these soils, its formation pathways are still under debate: either neoformation by dissolution-crystallisation reactions or solid-state transformation of 2:1 phyllosilicates. To elucidate this, weathering sequences in a unique 40 m core taken below a termite mound, reaching a talc-chlorite bearing substrate in the Lubumbashi area, Katanga, DR Congo are being investigated in detail using a.o. quantitative X-ray diffraction analysis, chemical characterization, micromorphology and µXRF-scanning with the main objective to improve the understanding of the formation pathways of kaolinite subgroup minerals in humid tropical environments. Based on an initial characterization of the core, two zones of interest were selected for more detailed analysis, for which the early findings will be presented. The first zone extends from ca. 9 m to 11 m below the surface is dominated by kaolinite but shows early traces of primary talc and micas. The second zone extends from 34 to 36 m below the surface and contains large amounts of chlorite, with smaller amounts of talc, micas and kaolinite.

Has the use of talc an effect on yield and extra virgin olive oil quality?

PubMed

Caponio, Francesco; Squeo, Giacomo; Difonzo, Graziana; Pasqualone, Antonella; Summo, Carmine; Paradiso, Vito Michele

2016-08-01

The maximization of both extraction yield and extra virgin olive oil quality during olive processing are the main objectives of the olive oil industry. As regards extraction yield, it can be improved by both acting on time/temperature of malaxation and using physical coadjuvants. It is well known that, generally, increasing temperature of malaxation gives an increase in oil extraction yield due to a reduction in oily phase viscosity; however, high malaxation temperature can compromise the nutritional and health values of extra virgin olive oil, leading to undesirable effects such as accelerated oxidative process and loss of volatile compounds responsible for oil flavor and fragrance. The addition of physical coadjuvants in olive oil processing during the malaxation phase, not excluded by EC regulations owing to its exclusively physical action, is well known to promote the breakdown of oil/water emulsions and consequently make oil extraction easier, thus increasing the yield. Among physical coadjuvants, micronized natural talc is used for olive oil processing above all for Spanish and Italian olive cultivars. The quality of extra virgin olive oil depends on numerous variables such as olive cultivar, ripeness degree and quality, machines utilized for processing, oil storage conditions, etc. However, the coadjuvants utilized in olive processing can also influence virgin olive oil characteristics. The literature highlights an increase in oil yield by micronized natural talc addition during olive processing, whereas no clear trend was observed as regards the chemical, nutritional and sensory characteristics of extra virgin olive oil. Although an increase in oil stability was reported, no effect of talc was found on the evolution of virgin olive oil quality indices during storage. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Hazard-evaluation and technical-assistance report No. ta-77-68, McDaniel Art Studio, Cincinnati, Ohio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kronoveter, K.J.

1978-06-01

In response to a request from the McDaniel Art Studio, located in Cincinnati, Ohio, an investigation was made of possible hazardous working conditions at the site, specifically the exposure to dust during sculpturing. Air sampling revealed potential dust exposures as high as 50 mg/m3 of total dust while using a powered disc grinder to sculpt. The sculpting process involved grinding with a 6-inch electric disc grinder or using such hand tools as files and chisels. The sculptor used primarily limestone, marble, talc, and onyx, working about 6 hours per day. The talc sculpting stone showed the presence of asbestos onmore » bulk analysis. The sculptor wore safety glasses with side shields and an appropriate, approved respirator. An industrial vacuum cleaner was used for dust cleanup. The author recommends that the sculptor continue to use the NIOSH approved respirator and that, if possible, the disc grinder not be used on potential asbestos sources such as serpentine and talc. Wet working of the stone would reduce the dust levels significantly. Several precautionary measures are listed from a publication dealing with the health risks associated with common art and hobby materials.« less

Misconceptions regarding the pathogenicity of silicas and silicates.

PubMed

Feigin, D S

1989-01-01

Several inhaled substances, from occupational or other environmental exposure, produce significant pulmonary disease and abnormalities demonstrated by pulmonary imaging. Areas of controversy and misconception relate principally to the extent and nature of both the clinical disease and the imaging abnormalities specific to each substance. The size and shape of the inhaled particles is an important determinant of the nature and severity of the disease produced, with fibrous shapes usually being the most pathogenetic. Fibrogenicity is another important pathogenetic characteristic of talc and kaolin, as well as asbestos. Talc produces four distinct forms of pulmonary disease, depending not only on the other substances with which it is inhaled, but also whether it is inhaled or injected intravenously. When inhaled alone, talc does not appear to produce significant pulmonary fibrosis or malignancy. Kaolin, mica, fuller's earth, zeolite, and fiberglass all vary in disease production according to their shape and fibrogenicity. Silica, diatomaceous earth, and other forms of silica are all highly fibrogenic and thus produce clinically obvious disease with sufficient inhalation. The largest particles usually produce nodular patterns in the upper pulmonary fields, as is typical of silicosis. The fibrous particles are more likely to manifest themselves as interstitial patterns in the lower pulmonary fields.

Separation of aflatoxin B1 from synthetic physiological fluids using talc and diatomite: Kinetic and isotherm aspects.

PubMed

Sprynskyy, Myroslav; Krzemień-Konieczka, Iwona; Gadzała-Kopciuch, Renata; Buszewski, Bogusław

2018-01-01

The objective of the study was to examine adsorption of the aflatoxin B1 from synthetic gastric fluid and synthetic intestinal fluid by talc, raw and calcined diatomite. The kinetic and equilibrium adsorption processes were studied in the batch adsorption experiments applying high performance liquid chromatography for the aflatoxin B1 determination. The kinetic study showed a very fast adsorption of the aflatoxin B1 onto the selected adsorbents from the both physiological fluids with reaching equilibrium within 1-15min. The aflatoxin B1 was almost completely adsorbed in initial linear step of the kinetic process that can be described well by the zero-order kinetics model. The experimental data of the equilibrium adsorption were characterized using the Langmuir and Freundlich isotherm models. The high adsorption effectiveness was found in a range of 90%-100% and 60%-100% for the diatomite samples and the talc respectively at the initial concentrations of the aflatoxin B1 as 31-300ng/mL. The possible mechanisms of the aflatoxin adsorption onto the used mineral adsorbents are also discussed in the work. Copyright © 2017 Elsevier B.V. All rights reserved.

MRI evaluation of infectious and non-infectious synovitis: preliminary studies in a rabbit model.

PubMed

Strouse, P J; Londy, F; DiPietro, M A; Teo, E L; Chrisp, C E; Doi, K

1999-05-01

Literature on magnetic resonance imaging (MR) evaluation of inflammatory joint effusions is sparse. To describe an animal model for studying infectious and non-infectious joint effusions with magnetic resonance imaging. Ten rabbit knees with septic arthritis and four with talc synovitis were imaged with MR. Contralateral knees injected with saline served as controls. Fat saturation T2-weighted and gadolinium-enhanced T1-weighted images were assessed for joint effusion, and periarticular and adjacent intraosseous increased signal or enhancement. Each knee was cultured and underwent pathologic examination. Both Staphylococcus aureus and talc produced effusions in all knees. The degree of periarticular signal and enhancement was greater in infected knees than talc-injected knees. No abnormal enhancement was seen within bone. Pathologic examination showed a greater degree of inflammation and joint destruction in the infected knees, but no evidence of osteomyelitis. A greater degree of abnormal signal and enhancement seen on MR suggests a more vigorous inflammatory process, as seen with septic arthritis. In spite of advanced septic arthritis, no enhancement was evident within bone, suggesting that enhancement within bone is not an expected finding in isolated septic arthritis and should raise concern for osteomyelitis.

Soapstones from the Ossola Valley (Piedmont, northern Italy)

NASA Astrophysics Data System (ADS)

Cavallo, Alessandro

2017-04-01

The term "soapstones" is referred to "soft", easily workable stones (talc and/or chlorite-rich metamorphic rocks, deriving from mafic - ultramafic protoliths), typically used for jars, pots and pipes. The term has been also improperly extended to "harder" varieties (e.g. serpentinites), mostly suitable for roof slabs and millstones. These rocks are characterized by easy workability and fire-resistance, and they had a remarkable historical, artistic and archaeological importance. In the Ossola region (Piedmont, northern Italy), the soapstones are traditionally known as "Pietra Laugera", "Pietra Lavizzaria" or "Pietra Ollare", and represent one of the oldest stony raw materials used since the Bronze Age (archaeological find in the Toceno surroundings, Vigezzo Valley). The discovery of archaeological handmade objects in the surroundings of the Ossola Valley testifies a massive use of green stones during the I century A.D., even for cinerary urns and grave outfits. A lot of two handles pots and milk vessels date back to the Middle Ages, as well as millstones and water pipes. Artistic and ornamental uses are documented in churches and civil buildings: for example, columns, capitals, pilasters and bas-reliefs (Sacro Monte del Calvario chapels, now UNESCO heritage, and the Collegiale Church in Domodossola) as well as fireplaces (e.g. Silva Palace in Domodossola), sculptures, ornaments and balustrades. The productivity reached the top in the XIX century and stopped in the twenties; nowadays the extraction occurs only in the Loana Valley, with a very limited production. The historical soapstones derive both from ophiolitic complexes (Antrona and Zermatt-Saas Zones) and from the ultramafic complexes within the Orselina-Moncucco-Isorno Zone, Monte Leone nappe and Sesia-Lanzo Zone. The historical quarries are usually small (even erratic boulders), and scattered over many lateral valleys, such as Brevettola, Antrona, Bognanco and Loana. A total of 52 representative samples were selected from all the abandoned quarries and analyzed, in order to highlight differences and relations among mineralogy and microstructures (PLOM, quantitative XRPD, SEM-EDS, WDS), whole-rock geochemistry (ICP-AES and ICP-MS) and porosity (Hg-intrusion porosimetry - MIP). The mineralogical and petrographic investigations evidenced a marked mineralogical and textural heterogeneity, ranging from talc-olivine-chlorite felses, talc-amphibole-carbonate felses, serpentinized peridotites up to talc-bearing serpentinites. The microstructures range from massive, coarse grained talc-bearing peridotites, to mylonitic serpentinites with non-pseudomorphic textures. From a geochemical point of view, there is a marked variability in major and trace-elements, due to the lithological heterogeneity and the variable serpentinization and carbonation degree. The total porosity values (MIP) range between 0.07% (Bognanco mylonitic serpentinite) and 1.06% (Moncucco talc-amphibole-carbonate fels). This research represents a first attempt of archaeometric study for the soapstones from the Ossola Valley: it evidences the usefulness of a combined mineralogical, petrographical and geochemical approach in order to identify the exploitation and provenance sites.

WATER STABILITY OF FILLED ELASTOMERS,

DTIC Science & Technology

ELECTRICAL INSULATION, *BUTYL RUBBER , ELASTOMERS, STABILITY, STABILITY, HYDROLYSIS, CURING AGENTS, ADDITIVES, WATER, ABSORPTION, THICKNESS, ELECTRICAL RESISTANCE, LEAKAGE(ELECTRICAL), DIFFUSION, TALC, ELECTRIC CABLES.

Synergistic effects of nucleating agents and plasticizers on the crystallization behavior of poly(lactic acid).

PubMed

Shi, Xuetao; Zhang, Guangcheng; Phuong, Thanh Vu; Lazzeri, Andrea

2015-01-19

The synergistic effect of nucleating agents and plasticizers on the thermal and mechanical performance of PLA nanocomposites was investigated with the objective of increasing the crystallinity and balancing the stiffness and toughness of PLA mechanical properties. Calcium carbonate, halloysite nanotubes, talc and LAK (sulfates) were compared with each other as heterogeneous nucleating agents. Both the DSC isothermal and non-isothermal studies indicated that talc and LAK were the more effective nucleating agents among the selected fillers. Poly(D-lactic acid) (PDLA) acted also as a nucleating agent due to the formation of the PLA stereocomplex. The half crystallization time was reduced by the addition of talc to about 2 min from 37.5 min of pure PLA by the isothermal crystallization study. The dynamic mechanical thermal study (DMTA) indicated that nanofillers acted as both reinforcement fillers and nucleating agents in relation to the higher storage modulus. The plasticized PLA studied by DMTA indicated a decreasing glass transition temperature with the increasing of the PEG content. The addition of nanofiller increased the Young's modulus. PEG had the plasticization effect of increasing the break deformation, while sharply decreasing the stiffness and strength of PLA. The synergistic effect of nanofillers and plasticizer achieved the balance between stiffness and toughness with well-controlled crystallization.

Interference of 1:1 and 2:1 layered phyllosilicates as excipients with ranitidine.

PubMed

Li, Zhaohui; Fitzgerald, Nicole M; Albert, Zachary; Jiang, Wei-Teh

2016-04-01

As natural ingredients and excipients, kaolinite and talc were frequently studied for their interactions with drugs in pharmaceutical formulations. In this study, the uptake of ranitidine (RT) on these two minerals was studied under different physic-chemical conditions and the mechanism of RT uptake on these two minerals contrasted. Although the thermodynamic and kinetic RT uptake on these two minerals was similar and the RT uptake on both minerals were limited to the external surfaces only, drastic difference in RT uptake was found under different equilibrium solution pH and ionic strength conditions. As cation exchange process was strongly affected by solution pH and ionic strength, the RT uptake on kaolinite was dominated by cation exchange and electrostatic interactions, while the RT uptake on talc was more controlled by inter- and intra- molecular hydrogen bonding interactions. For kaolinite, the limiting factor for RT uptake was the specific surface area due to monolayer RT adsorption. In contract, multilayer RT uptake was found on talc surfaces. No matter which mechanism dominated RT uptake on these minerals, the interaction should not be neglected in pharmaceutical formulations should these minerals be used as additives and/or excipients. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanical Mixing and Metamorphism of Mafic and Ultramafic Lithologies during Mylonisis at the ST. Paul Transform System, Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Adrião, Á.; Maia, M.; Hemond, C.; Kaczmarek, M. A.; Briais, A.; Vincent, C.; Brunelli, D.

2017-12-01

The St. Paul Transform System offsets by 630 km the Equatorial Mid Atlantic Ridge at 1° N. It consists of four major faults separating three intra transform ridge axes. This region shows a transition from a transpressive, hot spot affected, regional-scale shear zone to the North to a region dominated by a particular oceanic core complex spreading to the South (Vincent et al., this congress). Samples collected in the region during the COLMEIA cruise (Maia et al., 2016) were studied for textures and whole-rock major and trace element contents. All samples experienced pervasive deformation at ductile to brittle conditions overprinted by late low-T alteration. Mylonitic and ultramylonitic rocks can be grouped in three main types: peridotitic, gabbroic and talc-chlorite schist. Peridotitic ultramylonites preserve few opx, cpx and sp porphyroclasts; they have homogeneous nano-micro grain size groundmass, banded foliation and late amphibole and sulfide crystallization. Locally S-C fabric overprints the mylonitic texture. Micro cracks, filled with serpentine, chlorite and oxides are common, as well fluid inclusions trails in olivine and plagioclase crystals of peridotite and gabbros respectively. Major and trace element content of the peridotitic mylonites plot in the depleted field of the abyssal peridotites; however, they present marked LREE enrichment and Eu positive anomaly. Gabbroic and talc-chlorite mylonites display REE-enriched patterns (up to 100x CI) and variable Eu anomalies. Major elements show a remarkable linear trend in the talc-chlorite group suggesting mixing of pure talc and chlorite end-members. These compositional characteristics suggest variable assimilation of MORB and E-MORB during mylonisis or early melt-rock interaction and hydrothermal evolution at variable metamorphic conditions. Vincent et al., 2017. Particular Oceanic Core Complex evolution …; this congress Maia et al., 2016. Extreme mantle uplift and exhumation ... Nat. Geo. doi:10.1038/ngeo2759

Protocol of the Australasian Malignant Pleural Effusion (AMPLE) trial: a multicentre randomised study comparing indwelling pleural catheter versus talc pleurodesis

PubMed Central

Fysh, Edward T H; Thomas, Rajesh; Read, Catherine A; Lam, Ben C H; Yap, Elaine; Horwood, Fiona C; Lee, Pyng; Piccolo, Francesco; Shrestha, Ranjan; Garske, Luke A; Lam, David C L; Rosenstengel, Andrew; Bint, Michael; Murray, Kevin; Smith, Nicola A; Lee, Y C Gary

2014-01-01

Introduction Malignant pleural effusion can complicate most cancers. It causes breathlessness and requires hospitalisation for invasive pleural drainages. Malignant effusions often herald advanced cancers and limited prognosis. Minimising time spent in hospital is of high priority to patients and their families. Various treatment strategies exist for the management of malignant effusions, though there is no consensus governing the best choice. Talc pleurodesis is the conventional management but requires hospitalisation (and substantial healthcare resources), can cause significant side effects, and has a suboptimal success rate. Indwelling pleural catheters (IPCs) allow ambulatory fluid drainage without hospitalisation, and are increasingly employed for management of malignant effusions. Previous studies have only investigated the length of hospital care immediately related to IPC insertion. Whether IPC management reduces time spent in hospital in the patients’ remaining lifespan is unknown. A strategy of malignant effusion management that reduces hospital admission days will allow patients to spend more time outside hospital, reduce costs and save healthcare resources. Methods and analysis The Australasian Malignant Pleural Effusion (AMPLE) trial is a multicentred, randomised trial designed to compare IPC with talc pleurodesis for the management of malignant pleural effusion. This study will randomise 146 adults with malignant pleural effusions (1:1) to IPC management or talc slurry pleurodesis. The primary end point is the total number of days spent in hospital (for any admissions) from treatment procedure to death or end of study follow-up. Secondary end points include hospital days specific to pleural effusion management, adverse events, self-reported symptom and quality-of-life scores. Ethics and dissemination The Sir Charles Gairdner Group Human Research Ethics Committee has approved the study as have the ethics boards of all the participating hospitals. The trial results will be published in peer-reviewed journals and presented at scientific conferences. Trial registration numbers Australia New Zealand Clinical Trials Registry—ACTRN12611000567921; National Institutes of Health—NCT02045121. PMID:25377015

Hydrothermal Upflow, Serpentinization and Talc Alteration Associated with a High Angle Normal Fault Cutting an Oceanic Detachment, Northern Apennines, Italy

NASA Astrophysics Data System (ADS)

Alt, J.; Crispini, L.; Gaggero, L.; Shanks, W. C., III; Gulbransen, C.; Lavagnino, G.

2017-12-01

Normal faults cutting oceanic core complexes are observed at the seafloor and through geophysics, and may act as flow pathways for hydrothermal fluids, but we know little about such faults in the subsurface. We present bulk rock geochemistry and stable isotope data for a fault that acted as a hydrothermal upflow zone in a seafloor ultramafic-hosted hydrothermal system in the northern Apennines, Italy. Peridotites were exposed on the seafloor by detachment faulting, intruded by MORB gabbros, and are overlain by MORB lavas and pelagic sediments. North of the village of Reppia are fault shear zones in serpentinite, oriented at a high angle to the detachment surface and extending 300 m below the paleo-seafloor. The paleo-seafloor strikes roughly east-west, dipping 30˚ to the north. At depth the fault zone occurs as an anticlinal form plunging 40˚ to the west. A second fault strikes approximately north-south, with a near vertical dip. The fault rock outcrops as reddish weathered talc + sulfide in 0.1-2 m wide anastomosing bands, with numerous splays. Talc replaces serpentinite in the fault rocks, and the talc rocks are enriched in Si, metals (Fe, Cu, Pb), Light Rare Earth Elements (LREE), have variable Eu anomalies, and have low Mg, Cr and Ni contents. In some cases gabbro dikes are associated with talc-alteration and may have enhanced fluid flow. Sulfide from a fault rock has d34S=5.7‰. The mineralogy and chemistry of the fault rocks indicate that the fault acted as the upflow pathway for high-T black-smoker type fluids. Traverses away from the fault (up to 1 km) and with depth below the seafloor (up to 500 m) reveal variable influences of hydrothermal fluids, but there are no consistent trends with distance. Background serpentinites 500 m beneath the paleoseafloor have LREE depleted trends. Other serpentinites exhibit correlations of LREE with HFSE as the result of melt percolation, but there is significant scatter, and hydrothermal effects include LREE enrichment, positive Eu anomalies, decreased MgO/SiO2, and increases in Sr and Cs. One serpentinite 40 m from the fault has d34S = 4.5‰, consistent with a hydrothermal sulfur source. Far from the fault (1 km) ophicalcites near the paleo-seafloor have negative Ce anomalies indicating seawater alteration, and suggesting a limit to hydrothermal influence on the length scale of 1 km.

Friction measurements in piston-cylinder apparatus using quartz-coesite reversible transition

NASA Technical Reports Server (NTRS)

Akella, J.

1979-01-01

The value of friction determined by monitoring piston displacement as a function of nominal pressure on compression and decompression cycles at 1273 K is compared with the friction value obtained by reversing the quartz-coesite transition at 1273 and 1073 K in a talc-glass-alsimag cell (Akella and Kennedy, 1971) and a low-friction salt cell (Mirwald et al., 1975). Quenching runs at 1273 K gave double values of friction of 0.25 GPa for the talc-glass-alsimag cell and 0.03 GPa for the salt cell. The piston-displacement technique gave somewhat higher values. Use of piston-displacement hysteresis loops in evaluating the actual pressure on a sample may lead to overestimates for decompression runs and underestimates for compression runs.

Comparison between Gaussian-type orbitals and plane wave ab initio density functional theory modeling of layer silicates: Talc [Mg{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}] as model system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulian, Gianfranco; Valdrè, Giovanni, E-mail: giovanni.valdre@unibo.it; Tosoni, Sergio

2013-11-28

The quantum chemical characterization of solid state systems is conducted with many different approaches, among which the adoption of periodic boundary conditions to deal with three-dimensional infinite condensed systems. This method, coupled to the Density Functional Theory (DFT), has been proved successful in simulating a huge variety of solids. Only in relatively recent years this ab initio quantum-mechanic approach has been used for the investigation of layer silicate structures and minerals. In the present work, a systematic comparison of different DFT functionals (GGA-PBEsol and hybrid B3LYP) and basis sets (plane waves and all-electron Gaussian-type orbitals) on the geometry, energy, andmore » phonon properties of a model layer silicate, talc [Mg{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}], is presented. Long range dispersion is taken into account by DFT+D method. Results are in agreement with experimental data reported in literature, with minimal deviation given by the GTO/B3LYP-D* method regarding both axial lattice parameters and interaction energy and by PW/PBE-D for the unit-cell volume and angular values. All the considered methods adequately describe the experimental talc infrared spectrum.« less

Mechanism for Angular Deformation of L-shaped Specimens —Influence of Filling Material and Shrinkage Factor—

NASA Astrophysics Data System (ADS)

Furuhashi, Hiroshi; Aoki, Takerou; Okabe, Sayaka; Arai, Tsuyoshi; Seto, Masahiro; Yamabe, Masashi

L-shape is the important and fundamental shape for injection molded parts. Therefore to reveal the corner angular deformation mechanism of this shape is also valuable for understanding the warpage mechanism of injection molded parts. In this study, we investigated the influence of the filling materials (fiber, talc and not filled) and two kinds of anisotropic shrinkage factors, solidification shrinkage and shrinkage caused by thermal expansion coefficient during cooling, to the angular deformation of L-shaped specimens and the following conclusions were obtained 1) The anisotropic solidification shrinkage of MD/TD and the anisotropic thermal expansion coefficient of MD/TD are considered to cause the angular deformation of L-shaped specimens. But the contribution ratios of these two anisotropies depend on the filling material for plastics. 2) The angular deformation of PP and PBT filled with glass fiber is mainly caused by the anisotropic thermal expansion coefficient and on the other hand, that of PP and PBT without filling material is caused by anisotropic solidification shrinkage. However both anisotropies cause the angular deformation of PP filled with talc. 3) The plate thickness dependence of the angular deformation of PP filled with talc is the singular peculiar phenomenon. The plate thickness dependence of anisotropic solidification shrinkage of this material (it is also singular) is considered to have an important influence on this phenomenon.

Talc

MedlinePlus

... Shade % Asbestos by PLM % Asbestos by TEM Black Opal True Color Liquid Foundation Heavenly Honey NAD NAD ... Face Powder Translucent 070-24 NAD NAD Black Opal Color Fusion Powder Mosaic Raspberry Bronzer NAD NAD ...

Occupational Respiratory Disease

MedlinePlus

... other particles. Types of occupational respiratory disease include: coal workers’ pneumoconiosis, also known as Black Lung Disease ... include: Dust from things such as wood, cotton, coal, asbestos, silica, and talc. Pesticides, drug or enzyme ...

Overview of Poisoning

MedlinePlus

... Soap and soap products (including hand soap) Spermaceti Starch and sizing Stearic acid Sunscreens Talc (except when ... In the United States, widespread use of child-resistant containers with safety caps has greatly reduced the ...

Development of a Dry Inoculation Method for Thermal Challenge Studies in Low-Moisture Foods by Using Talc as a Carrier for Salmonella and a Surrogate (Enterococcus faecium).

PubMed

Enache, Elena; Kataoka, Ai; Black, D Glenn; Napier, Carla D; Podolak, Richard; Hayman, Melinda M

2015-06-01

The objective of this study was to obtain dry inocula of Salmonella Tennessee and Enterococcus faecium, a surrogate for thermal inactivation of Salmonella in low-moisture foods, and to compare their thermal resistance and stability over time in terms of survival. Two methods of cell growth were compared: cells harvested from a lawn on tryptic soy agar (TSA-cells) and from tryptic soy broth (TSB-cells). Concentrated cultures of each organism were inoculated onto talc powder, incubated at 35 °C for 24 h, and dried for additional 24 h at room temperature (23 ± 2 °C) to achieve a final water activity of ≤ 0.55 before sieving. Cell reductions of Salmonella and E. faecium during the drying process were between 0.14 and 0.96 log CFU/g, depending on growth method used. There was no difference between microbial counts at days 1 and 30. Heat resistance of the dry inoculum on talc inoculated into a model peanut paste (50 % fat and 0.6 water activity) was determined after 1 and 30 days of preparation, using thermal death time tests conducted at 85 °C. For Salmonella, there was no significant difference between the thermal resistance (D(85 °C)) for the TSB-cells and TSA-cells (e.g. day 1 cells D(85 °C) = 1.05 and 1.07 min, respectively), and there was no significant difference in D(85 °C) between dry inocula on talc used either 1 or 30 days after preparation (P > 0.05). However, the use the dry inocula of E. faecium yielded different results: the TSB-grown cells had a significantly (P < 0.05) greater heat resistance than TSA-grown cells (e.g. D(85 °C) for TSB-cells = 3.42 min versus 2.60 min for TSA-cells). E. faecium had significantly (P < 0.05) greater heat resistance than Salmonella Tennessee regardless what cell type was used for dry inoculum preparation; therefore, it proved to be a conservative but appropriate surrogate for thermal inactivation of Salmonella in low-moisture food matrices under the tested conditions.

Protocol of the Australasian Malignant Pleural Effusion (AMPLE) trial: a multicentre randomised study comparing indwelling pleural catheter versus talc pleurodesis.

PubMed

Fysh, Edward T H; Thomas, Rajesh; Read, Catherine A; Kwan, Ben C H; Lam, Ben C H; Yap, Elaine; Horwood, Fiona C; Lee, Pyng; Piccolo, Francesco; Shrestha, Ranjan; Garske, Luke A; Lam, David C L; Rosenstengel, Andrew; Bint, Michael; Murray, Kevin; Smith, Nicola A; Lee, Y C Gary

2014-11-06

Malignant pleural effusion can complicate most cancers. It causes breathlessness and requires hospitalisation for invasive pleural drainages. Malignant effusions often herald advanced cancers and limited prognosis. Minimising time spent in hospital is of high priority to patients and their families. Various treatment strategies exist for the management of malignant effusions, though there is no consensus governing the best choice. Talc pleurodesis is the conventional management but requires hospitalisation (and substantial healthcare resources), can cause significant side effects, and has a suboptimal success rate. Indwelling pleural catheters (IPCs) allow ambulatory fluid drainage without hospitalisation, and are increasingly employed for management of malignant effusions. Previous studies have only investigated the length of hospital care immediately related to IPC insertion. Whether IPC management reduces time spent in hospital in the patients' remaining lifespan is unknown. A strategy of malignant effusion management that reduces hospital admission days will allow patients to spend more time outside hospital, reduce costs and save healthcare resources. The Australasian Malignant Pleural Effusion (AMPLE) trial is a multicentred, randomised trial designed to compare IPC with talc pleurodesis for the management of malignant pleural effusion. This study will randomise 146 adults with malignant pleural effusions (1:1) to IPC management or talc slurry pleurodesis. The primary end point is the total number of days spent in hospital (for any admissions) from treatment procedure to death or end of study follow-up. Secondary end points include hospital days specific to pleural effusion management, adverse events, self-reported symptom and quality-of-life scores. The Sir Charles Gairdner Group Human Research Ethics Committee has approved the study as have the ethics boards of all the participating hospitals. The trial results will be published in peer-reviewed journals and presented at scientific conferences. Australia New Zealand Clinical Trials Registry-ACTRN12611000567921; National Institutes of Health-NCT02045121. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Cell Phones: Current Research Results

MedlinePlus

... possibly carcinogenic to humans": Coffee Extremely low frequency electromagnetic fields (power line frequency) Talc-based body powder ... Effects of Wireless Communication Devices World Health Organization: Electromagnetic Fields and Public Health: Mobile Phones International Agency ...

21 CFR 182.90 - Substances migrating to food from paper and paperboard products.

Code of Federal Regulations, 2012 CFR

2012-04-01

... sorbate. Sodium tripolyphosphate. Sorbitol. Soy protein, isolated. Starch, acid modified. Starch, pregelatinized. Starch, unmodified. Talc. Vanillin. Zinc hydrosulfite. Zinc sulfate. [42 FR 14640, Mar. 15, 1977...

21 CFR 182.90 - Substances migrating to food from paper and paperboard products.

Code of Federal Regulations, 2010 CFR

2010-04-01

... sorbate. Sodium tripolyphosphate. Sorbitol. Soy protein, isolated. Starch, acid modified. Starch, pregelatinized. Starch, unmodified. Talc. Vanillin. Zinc hydrosulfite. Zinc sulfate. [42 FR 14640, Mar. 15, 1977...

21 CFR 182.90 - Substances migrating to food from paper and paperboard products.

Code of Federal Regulations, 2013 CFR

2013-04-01

... sorbate. Sodium tripolyphosphate. Sorbitol. Soy protein, isolated. Starch, acid modified. Starch, pregelatinized. Starch, unmodified. Talc. Vanillin. Zinc hydrosulfite. Zinc sulfate. [42 FR 14640, Mar. 15, 1977...

21 CFR 182.90 - Substances migrating to food from paper and paperboard products.

Code of Federal Regulations, 2011 CFR

2011-04-01

... sorbate. Sodium tripolyphosphate. Sorbitol. Soy protein, isolated. Starch, acid modified. Starch, pregelatinized. Starch, unmodified. Talc. Vanillin. Zinc hydrosulfite. Zinc sulfate. [42 FR 14640, Mar. 15, 1977...

Tips for Improving Seed Planting Efficiency

Treesearch

R. Kasten Dumroese; David L. Wenny; Susan J. Morrison

2002-01-01

The efficiency of a precision seeder was improved by adding a mirror so employees could monitor seed levels and by marking seeds with brightly colored talc to quickly verify the accuracy of the machine.

21 CFR 182.90 - Substances migrating to food from paper and paperboard products.

Code of Federal Regulations, 2014 CFR

2014-04-01

... paperboard products used in food packaging that are generally recognized as safe for their intended use... protein, isolated. Starch, acid modified. Starch, pregelatinized. Starch, unmodified. Talc. Vanillin. Zinc...

Biodegradable compounds: Rheological, mechanical and thermal properties

NASA Astrophysics Data System (ADS)

Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

2015-12-01

Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

Effect of Antiadherents on the Physical and Drug Release Properties of Acrylic Polymeric Films.

PubMed

Ammar, Hussein O; Ghorab, Mamdouh M; Felton, Linda A; Gad, Shadeed; Fouly, Aya A

2016-06-01

Antiadherents are used to decrease tackiness of a polymer coating during both processing and subsequent storage. Despite being a common excipient in coating formulae, antiadherents may affect mechanical properties of the coating film as well as drug release from film-coated tablets, but how could addition of antiadherents affect these properties and to what extent and is there a relation between the physical characteristics of the tablet coat and the drug release mechanisms? The aim of this study was to evaluate physical characteristics of films containing different amounts of the antiadherents talc, glyceryl monostearate, and PlasACRYL(TM) T20. Eudragit RL30D and Eudragit RS30D as sustained release polymers and Eudragit FS30D as a delayed release material were used. Polymer films were characterized by tensile testing, differential scanning calorimetry (DSC), microscopic examination, and water content as calculated from loss on drying. The effect of antiadherents on in vitro drug release for the model acetylsalicylic acid tablets coated with Eudragit FS30D was also determined. Increasing talc concentration was found to decrease the ability of the polymer films to resist mechanical stress. In contrast, glyceryl monostearate (GMS) and PlasACRYL produced more elastic films. Talc at concentrations higher than 25% caused negative effects, which make 25% concentration recommended to be used with acrylic polymers. All antiadherents delayed the drug release at all coating levels; hence, different tailoring of drug release may be achieved by adjusting antiadherent concentration with coating level.

Dehydration kinetics of talc and 10 Å phase: Consequences for subduction zone seismicity

NASA Astrophysics Data System (ADS)

Chollet, Mélanie; Daniel, Isabelle; Koga, Kenneth T.; Petitgirard, Sylvain; Morard, Guillaume

2009-06-01

The process of dehydration embrittlement is usually proposed as an explanation for the presence of intermediate-depth earthquakes in subduction zones. It assumes that the release of water by hydrous mineral breakdown is fast enough to provoke brittle failure. We performed high-pressure, high-temperature, dehydration experiments of talc and 10 Å phase coupled with in situ measurement of reaction kinetics using synchrotron X-ray diffraction. Newly developed, X-ray transparent, pressure-sealed, titanium capsule ensured a closed thermochemical environment. From isothermal kinetics data fitted to the Avrami's equation and from the texture of reaction products, we conclude that dehydration rates of these minerals are limited by diffusion. Predicted minimum rates of fluid release range from 10 - 4 to 9 × 10 - 6 m 3fluid m - 3 rock s - 1 , and are fast enough to provoke hydraulic rupture since Maxwell relaxation rate of rocks relevant of subduction zones are slower than the rate of fluid release. These rates are comparable between talc, 10 Å phase and antigorite also [Perrillat, J.-P., Daniel, I., Koga, K.T., Reynard, B., Cardon, H., Crichton, W.A., 2005. Kinetics of antigorite dehydration: a real-time X-ray diffraction study. Earth Planet. Sci. Lett. 236, 899-913]. Consequently, we suggest that the dehydration of hydrous minerals may eventually be fast enough to trigger the intermediate-depth earthquakes, and that the deepest among intermediate-depth earthquakes may actually locate the limits for dehydration of hydrous minerals in the downgoing lithosphere.

Bedside talc pleurodesis for malignant pleural effusion: factors affecting success.

PubMed

Aydogmus, Umit; Ozdemir, Servet; Cansever, Levent; Sonmezoglu, Yasar; Kocaturk, Celalettin Ibrahim; Bedirhan, Mehmet Ali

2009-03-01

To determine the factors affecting the success of bedside talc slurry (TS) used for symptomatic treatment of patients with malignant pleural effusion (MPE). Data of 113 effusions in 103 MPE patients treated between 1999 and 2007 were retrospectively evaluated for the study. The study group involved 73 patients whose follow-up information was available out of 81 patients treated by TS. Causes of MPE were lung cancer in 22 patients (30.1%) and breast carcinoma in 21 patients (28.8%). The success rate of TS was significantly higher if the time period between radiological diagnosis of effusion and administration of TS was less than 30 days (P= .02), or spontaneous expansion was attained after chest tube drainage (CTD) (P= .01). Success rate was higher for patients with daily drainage of less than 200 ml before TS than patients with more than 200 ml of daily drainage (P= .01). Dose of talc, either 4 g or above (P= .34), primary cause of MPE (P= .53), time to termination of CTD (P= .57), amount of drainage when CTD was terminated (P= .23), and time period between CTD and administration of TS (P= .20) did not show a statistically significant effect on the success of TS. In the treatment of malignant pleural effusion, patients with daily drainage of less than 200 ml before TS developed less recurrence than patients with daily drainage of more than 200 ml. Longer time period between the diagnosis of MPE and onset of CTD increased recurrence.

Presentations at 2013 Pollinator Summit --Dust Focus Group

EPA Pesticide Factsheets

These presentations covered pesticide exposure risks posed to honey bees by the dust from planting treated corn seed, and research on reducing dust by means such as talc replacement and standards for planter technology.

High-pressure Infrared Spectra of Tal and Lawsonite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott,H.; Liu, Z.; Hemley, R.

2007-01-01

We present high-pressure infrared spectra of two geologically important hydrous minerals: talc, Mg3Si4O10(OH)2 and lawsonite, CaAl2Si2O7(OH)2{center_dot}H2O,{center_dot}at room temperature. For lawsonite, our data span the far infrared region from 150 to 550 cm-1 and extend to 25 GPa. We combine our new spectroscopic data with previously published high-pressure mid-infrared and Raman data to constrain the Gr{umlt u}neisen parameter and vibrational density of states under pressure. In the case of talc, we present high-pressure infrared data that span both the mid and far infrared from 150 to 3800 cm-1 covering lattice, silicate, and hydroxyl stretching vibrations to a maximum pressure of 30more » GPa. Both phases show remarkable metastability well beyond their nominal maximum thermodynamic stability at simultaneous high-pressure and high-temperature conditions.« less

Percolation behaviour in the magnetic permeability and electrical conductivity in conducting magnetic - Insulating non magnetic binary composites

NASA Astrophysics Data System (ADS)

McLachlan, David S.; Doyle, Terence B.; Sauti, Godfrey

2018-07-01

Experimental results of the complex magnetic permeability (μ) and the electrical conductivity (σ) of a granular paramagnetic Gadolinium Gallium Garnet (GGG: 0.3-26 vol%) and Teflon (PTFE) system are presented and discussed in relation to previously published (conductivity) and unpublished (permeability) studies on granular Fe3O4 - talc and Ni - talc wax systems. In these systems plots of the real conductivity (σm‧) against the volume fraction (φ) lie on characteristic sigmoid curves that when fitted to the Two Exponent Phenomenological Percolation Equation (TEPPE) confirm the existence of "percolation microstructures" with critical volume fractions (φc). The plots of the real and imaginary permeability (μm‧) and (μm″) satisfactorily fit to the TEPPE using the φc obtained in each case from the "conductivity" measurements. In all three cases the conductivity results gave the exponent t > 2, and the permeability results gave t < 1.

Comparative analysis of cyanobacteria inhabiting rocks with different light transmittance in the Mojave Desert: a Mars terrestrial analogue

NASA Astrophysics Data System (ADS)

Smith, Heather D.; Baqué, Mickael; Duncan, Andrew G.; Lloyd, Christopher R.; McKay, Christopher P.; Billi, Daniela

2014-05-01

The Mojave Desert has been long considered a suitable terrestrial analogue to Mars in many geological and astrobiological aspects. The Silver Lake region in the Mojave Desert hosts several different rock types (talc, marble, quartz, white carbonate and red-coated carbonate) colonized by hypoliths within a few kilometres. This provides an opportunity to investigate the effect of rock type on hypolithic colonization in a given environment. Transmission measurements from 300 to 800 nm showed that the transmission of blue and UVA varied between rock types. The wavelength at which the transmission fell to 1% of the transmission at 600 nm was 475 nm for white carbonate and quartz, 425 nm for red-coated carbonate and talc and 380 nm for marble. The comparative analysis of the cyanobacterial component of hypoliths under different rocks, as revealed by sequencing 16S rRNA gene clone libraries, showed no significant variation with rock type; hypoliths were dominated by phylotypes of the genus Chroococcidiopsis, although less abundant phylotypes of the genus Loriellopsis, Leptolyngbya and Scytonema occurred. The comparison of the confocal laser scanning microscopy-λ (CLSM-λ) scan analysis of the spectral emission of the photosynthetic pigments of Chroococcidiopsis in different rocks with the spectrum of isolated Chroococcidiopsis sp. 029, revealed a 10 nm red shift in the emission fingerprinting for quartz and carbonate and a 5 nm red shift for talc samples. This result reflects the versatility of Chroococcidiopsis in inhabiting dry niches with different light availability for photosynthesis.

Energy and resource basis of an Italian coastal resort region integrated using emergy synthesis.

PubMed

Vassallo, Paolo; Paoli, Chiara; Tilley, David R; Fabiano, Mauro

2009-10-01

Sustainable development of coastal zones must balance economic development that encourages human visitation from a larger population with desires that differ from the local residents with the need to maintain opportunities for the local resident society and conserve ecological capital, which may serve as the basis for residents. We present a case study in which the sustainability level of a coastal zone (Riviera del Beigua), located along the Ligurian coast of north-western Italy, was assessed through the lens of systems ecology using emergy synthesis to integrate across economic, social and environmental sub-systems. Our purposes were (1) to quantify the environmental sustainability level of this coastal zone, (2) to evaluate the role of tourism in affecting the economy, society and environment, and (3) to compare emergy synthesis to Butler's Tourism Area Life Cycle model (TALC). Results showed that 81% of the total emergy consumption in the coastal zone was derived from external sources, indicating that this tourist-heavy community was not sustainable. Tourism, as the dominant economic sub-system, consumed 42% of the total emergy budget, while local residents used the remaining 58%. The progressive stages of the TALC model were found to parallel the dynamic changes in the ratio of external emergy inputs to local emergy inputs, suggesting that emergy synthesis could be a useful tool for detecting a tourist region's TALC stage. Use of such a quantitative tool could expedite sustainability assessment to allow administrative managers to understand the complex relationship between a region's economy, environment and resident society so sound policies can be developed to improve overall sustainability.

Hydrolytic weakening in olivine single crystals

NASA Astrophysics Data System (ADS)

Tielke, Jacob A.; Zimmerman, Mark E.; Kohlstedt, David L.

2017-05-01

Deformation experiments on single crystals of San Carlos olivine under hydrous conditions were performed to investigate the microphysical processes responsible for hydrolytic weakening during dislocation creep. Hydrogen was supplied to the crystals using either talc or brucite sealed in nickel capsules with the crystal. Deformation experiments were carried out using a gas medium apparatus at temperatures of 1050° to 1250°C, a confining pressure of 300 MPa, differential stresses of 45 to 294 MPa, and resultant strain rates of 1.5 × 10-6 to 4.4 × 10-4 s-1. For talc-buffered (i.e., water and orthopyroxene-buffered) samples at high temperatures, the dependence of strain rate on stress follows a power law relationship with a stress exponent (n) of ˜2.5 and an activation energy of ˜490 kJ/mol. Brucite-buffered samples deformed faster than talc-buffered samples but contained similar hydrogen concentrations, demonstrating that strain rate is influenced by orthopyroxene activity under hydrous conditions. The values of n and dependence of strain rate on orthopyroxene activity are consistent with hydrolytic weakening occurring in the climb-controlled dislocation creep regime that is associated with deformation controlled by lattice diffusion under hydrous conditions and by pipe diffusion under anhydrous conditions. Analyses of postdeformation electron-backscatter diffraction data demonstrate that dislocations with [100] Burgers vectors are dominant in the climb-controlled regime and dislocations with [001] are dominant in the glide-controlled regime. Comparison of the experimentally determined constitutive equations demonstrates that under hydrous conditions crystals deform 1 to 2 orders of magnitude faster than under anhydrous conditions.

Development and characterization of clay facial mask containing turmeric extract solid dispersion.

PubMed

Pan-On, Suchiwa; Rujivipat, Soravoot; Ounaroon, Anan; Tiyaboonchai, Waree

2018-04-01

To develop clay facial mask containing turmeric extract solid dispersion (TESD) for enhancing curcumin water solubility and permeability and to determine suitable clay based facial mask. The TESD were prepared by solvent and melting solvent method with various TE to polyvinylpyrrolidone (PVP) K30 mass ratios. The physicochemical properties, water solubility, and permeability were examined. The effects of clay types on physical stability of TESD, water adsorption, and curcumin adsorption capacity were evaluated. The TESD prepared by solvent method with a TE to PVP K30 mass ratio of 1:2 showed physically stable, dry powders, when mixed with clay. When TESD was dissolved in water, the obtained TESD micelles showed spherical shape with mean size of ∼100 nm resulting in a substantial enhancement of curcumin water solubility, ∼5 mg/ml. Bentonite (Bent) and mica (M) showed the highest water adsorption capacity. The TESD's color was altered when mixed with Bent, titanium dioxide (TiO 2 ) and zinc oxide (ZnO) indicating curcumin instability. Talcum (Talc) showed the greatest curcumin adsorption followed by M and kaolin (K), respectively. Consequently, in vitro permeation studies of the TESD mixed with Talc showed lowest curcumin permeation, while TESD mixed with M or K showed similar permeation profile as free TESD solutions. The developed TESD-based clay facial mask showed lower curcumin permeation as compared to those formulations with Tween 80. The water solubility and permeability of curcumin in clay based facial mask could be improved using solid dispersion technique and suitable clay base composed of K, M, and Talc.

Disruption of iron homeostasis in mesothelial cells following talc pleurodesis

EPA Science Inventory

The mechanism for biological effect following particle exposure is incompletely understood. One postulate proposed to explain biological effect after particles is an altered iron homeostasis in the host. The fibro-inflammatory properties of particles are exploited therapeutically...

A prospective algorithm for the management of air leaks after pulmonary resection.

PubMed

Cerfolio, R J; Tummala, R P; Holman, W L; Zorn, G L; Kirklin, J K; McGiffin, D C; Naftel, D C; Pacifico, A D

1998-11-01

Air leaks (ALs) are a common complication after pulmonary resection, yet there is no consensus on their management. An algorithm for the management of chest tubes (CT) and ALs was applied prospectively to 101 consecutive patients who underwent elective pulmonary resection. Air leaks were graded daily as forced expiratory only, expiratory only, inspiratory only, or continuous. All CTs were kept on 20 cm of suction until postoperative day 2 and were then converted to water seal. On postoperative day 3, if both a pneumothorax and AL were present, the CT was placed to 10 cm H2O of suction. If a pneumothorax was present without an AL, the CT was returned to 20 cm H2O of suction. Air leaks that persisted after postoperative day 7 were treated with talc slurry. There were 101 patients (67 men); on postoperative day 1, 26 had ALs and all were expiratory only. Univariable analysis showed a low ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) (p = 0.005), increased age (p = 0.007), increased ratio of residual volume to total lung capacity (RV/TLC) (p = 0.04), increased RV (p = 0.02), and an increased functional residual capacity (FRC) (p = 0.02) to predict the presence of an AL on postoperative day 1. By postoperative day 2, 22 patients had expiratory ALs. After 12 hours of water seal, 13 of the 22 patients' ALs had stopped, and 3 more sealed by the morning of postoperative day 3. However, 2 of the 6 patients whose ALs continued experienced a pneumothorax. Five of the 6 patients with ALs on postoperative day 4 still had ALs on postoperative day 7, and all were treated by talc slurry through the CT. All ALs resolved within 24 hours after talc slurry. Most ALs after pulmonary resection are expiratory only. A low FEV1/FVC ratio, increased age, increased RV/TLC ratio, increased RV, and an increased FRC were predictors of having an ALs on postoperative day 1. Conversion from suction to water seal is an effective way of sealing expiratory AL, and pneumothorax is rare. If an expiratory AL does not stop by postoperative day 4 it will probably persist until postoperative day 7, and talc slurry may be an effective treatment.

Some mineral stability relations in the system CaOMgOSiO2H2OHCl

USGS Publications Warehouse

Luce, R.W.; Cygan, G.L.; Hemley, J.J.; d'Angelo, W. M.

1985-01-01

Mineral-aqueous solution equilibria for the assemblages talc-quartz, tremolite-talc-quartz, diopside-tremolite-quartz, wollastonite-diopside-quartz and wollastonite-quartz have been studied at 2 kb total pressure, 500?? to 700??C and chloride concentrations from 0.03 to 6.0 molal. Most work was at 1 m chloride. Both buffered and unbuffered data were obtained and a recalibration of the Ag-AgCl buffer is presented. Log equilibrium quotients at 500??, 600?? and 700??C are respectively: Ta-Qz ( mMgCl2 mHCl2) 2.57, 1.71, 0.73; Tr-Ta-Qz and Di-Tr-Qz ( mCaCl2 mMgCl2mHCl2) 4.98, 3.99, 2.21 and 7.29, 5.30, 3.56; WoDi-Qz ( mCaCl2 mMgCl2) 3.30, 3.00, 2.79: Wo-Qz ( mCaCl2 mHCl2) 5.15, 3.95, 2.68. Mineral stability fields plotted in terms of these concentration data more tangibly represent the compositional character of real systems and the mass transfer capabilities of their fluids than do the analogous theoretical activity diagrams. Overall dissociation constants of MgCl2 and CaCl2 were calculated from the experimental data using the calculated ionic activity constants for the reactions and the established dissociation constants of HCl. The negative log values are respectively: 3.88. 6.63, 9.20 for CaCl2 and 4.60, 7.54, 10.37 for MgCl2 at 500??, 600?? and 700??C, 2 kb. The Ca values are about an order of magnitude more positive than the conductance-derived values by Frantz and Marshall (1982). The phase relations developed in this study have application to the genesis of talc, tremolite, and diopside-bearing assemblages in some regional metamorphic rocks, but more specifically to the calcsilicate skarn assemblages of many metasomatic aureoles. The equilibrium fluids are characterized by high concentrations of Ca relative to Mg and increasing Ca Mg ratios with decreasing temperatures. The stability fields of talc, tremolite, and quartz expand relative to those of diopside and wollastonite with decreasing temperature, hence their more common appearance as retrograde products in skarn systems. ?? 1985.

The efficacy of mechanical abrasion and talc slurry as methods of pleurodesis in normal dogs.

PubMed

Jerram, R M; Fossum, T W; Berridge, B R; Steinheimer, D N; Slater, M R

1999-01-01

To determine the efficacy of mechanical abrasion and talc slurry as methods for pleurodesis in normal dogs. Experimental study. Ten normal beagle dogs. Group I dogs had mechanical abrasion (MA) of the pulmonary and costal pleurae performed in one hemithorax with a dry gauze sponge with a median sternotomy approach. Group II dogs had 100 mL of a 1 g talc slurry (TS) administered into one hemithorax through a tube thoracostomy. Administration of the TS was visualized by using video thoracoscopy. All dogs were evaluated at 2, 10, 20, and 30 days postoperatively by means of thoracic radiography and ultrasonographic thoracic wall measurement. The dogs were euthanatized 30 days postoperatively and a gross necropsy was performed. Hemithoraces were assigned a pleurodesis score (0-4) and an obliteration grade (0-6). Tissues were collected for histopathologic examination of pulmonary pleura, costal pleura, and pleural adhesions. Pulmonary and costal pleurae were graded for the degree of fibrosis (0-4). Obliteration grade and costal pleural fibrosis score were significantly higher for the treated sides in the MA dogs compared with the TS dogs. MA Dogs: Mechanical abrasion dogs had pleurodesis, obliteration, and pleural fibrosis scores that were greater on the treated side than the untreated side, however, the differences were not statistically significant. Only two MA dogs had firm adhesion of the pulmonary pleura to the costal pleura in portions of the cranial and middle lung lobes in the treated hemithorax. Thoracic wall surface area covered with adhesions was 15% and 21% in each of these two dogs. The median pulmonary pleural fibrosis score of all MA dogs for the treated hemithorax was 3 compared to 0 on the untreated side. TS Dogs: There was no statistical difference for pleurodesis scores and obliteration grades between the treated and untreated sides. No dogs showed evidence of pulmonary to costal pleural adhesions. Histopathology showed talc crossover into the untreated side in all five dogs. Median pulmonary fibrosis score of the treated hemithorax was 1 compared with 0 on the untreated side. Neither method of pleurodesis produced sufficient pleural adhesions to obliterate the pleural space. It is possible that the degree of pulmonary pleural fibrosis present in MA dogs may be sufficient to limit air leakage from pulmonary blebs and bullae resulting in successful treatment of spontaneous pneumothorax.

21 CFR 82.1051 - Lakes (D&C).

Code of Federal Regulations, 2011 CFR

2011-04-01

..., gloss white, clay, titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or... radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium; or (ii) a salt prepared... subpart, by combining such color with the basic radical sodium, potassium, aluminum, barium, calcium...

21 CFR 82.1051 - Lakes (D&C).

Code of Federal Regulations, 2010 CFR

2010-04-01

..., gloss white, clay, titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or... radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium; or (ii) a salt prepared... subpart, by combining such color with the basic radical sodium, potassium, aluminum, barium, calcium...

21 CFR 82.1051 - Lakes (D&C).

Code of Federal Regulations, 2012 CFR

2012-04-01

..., gloss white, clay, titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or... radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium; or (ii) a salt prepared... subpart, by combining such color with the basic radical sodium, potassium, aluminum, barium, calcium...

21 CFR 82.1051 - Lakes (D&C).

Code of Federal Regulations, 2014 CFR

2014-04-01

..., gloss white, clay, titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or... radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium; or (ii) a salt prepared... subpart, by combining such color with the basic radical sodium, potassium, aluminum, barium, calcium...

21 CFR 82.1051 - Lakes (D&C).

Code of Federal Regulations, 2013 CFR

2013-04-01

..., gloss white, clay, titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or... radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium; or (ii) a salt prepared... subpart, by combining such color with the basic radical sodium, potassium, aluminum, barium, calcium...

Steatite and schist as contenders for the Global Heritage Stone Resource due to their importance in Brazil's natural stone built heritage

NASA Astrophysics Data System (ADS)

Gilberto Costa, Antônio

2013-04-01

In Brazil, European natural stones, such as marble and limestone, were used as building material at historically important buildings and monuments, mainly in coastal cities, as well as in contemporary urban centers. However, in the country's central region, these Italian and Portuguese marbles and limestones were scarcely used. Instead, they were substituted for soapstone and several types of schist. As of 1755, the former was employed because of the ease with which it can be worked, essentially in the sculptural art and in the production of ornamental elements. Characterized by the presence of talc, steatite can feature other minerals such as serpentine, chlorite, carbonate, amphiboles, oxides like hematite and magnetite, and sulfites like pyrite, all in broadly variable amounts, which can result in modification of its technological properties (Volumetric Weight, Porosity, Water Absorption, Uniaxial Compression, Abrasion Resistance, Thermal Expansion etc.). In such rocks, talc content will be a decisive factor in their coloration. The higher its talc content is the clearer and softer the stone type will be, which ends up being known as talc stone. In such cases, the rock can display different hues of green, blue and gray. When compared to other rocks, texture patterns containing talc crystals, chlorite and carbonate contribute to low absorption and porosity for steatites. Schists were equally used at historical buildings in the Brazilian inland, especially in constructions in Minas Gerais towns, both in the production of structural elements such as bases, corners, pillars and foundations and in the creation of ornaments. Featuring different compositions, such rocks - which almost always occur interlayered with other ones such as quartzite - display coloration ranging from hues of gray to green to blue. They can be quartz-sericite-albite-chlorite schists featuring great or no amounts of carbonate, magnetite, epidote and tourmaline, sometimes with garnet, such as in some of Caeté's monuments. They can range from silverfish to light green, such as the quartz-sericite schist from Diamantina, some of which contain variable amounts of kyanite, chlorite, or even chloritoid, as well as the presence of whitish bands rich with carbonate and quartz crystals, such as in Caeté and Sabará. They can be serpentine schist and chlorite schist, from quarries around Caraça Ridge and employed in historical buildings in Brumal and Catas Altas do Mato Dentro, to name but a few. They can as well be kyanite-garnet-mica schists, with coloration ranging from green to bluish green, outcropping on Itacolomy Ridge, near Passagem de Mariana, or, simply, sericite schist from Santo Antônio Hill, in the same region. They can also be muscovite-chlorite-quartz schists with magnetite either dispersed or concentrated in thin bands, extracted around Ouro Preto and locally applied, or those used in buildings in São João d'El Rey and Tiradentes which were extracted from old quarries situated in the Candoga region, between Santa Cruz and Tiradentes, or from quarries in the Mangue region.

21 CFR 720.4 - Information requested about cosmetic products.

Code of Federal Regulations, 2014 CFR

2014-04-01

... and talcum) (excluding aftershave talc). (iv) Sachets. (v) Other fragrance preparations. (5) Hair preparations (noncoloring). (i) Hair conditioners. (ii) Hair sprays (aerosol fixatives). (iii) Hair..., dressings, and other hair grooming aids. (viii) Wave sets. (ix) Other hair preparations. (6) Hair coloring...

21 CFR 720.4 - Information requested about cosmetic products.

Code of Federal Regulations, 2012 CFR

2012-04-01

... and talcum) (excluding aftershave talc). (iv) Sachets. (v) Other fragrance preparations. (5) Hair preparations (noncoloring). (i) Hair conditioners. (ii) Hair sprays (aerosol fixatives). (iii) Hair..., dressings, and other hair grooming aids. (viii) Wave sets. (ix) Other hair preparations. (6) Hair coloring...

21 CFR 720.4 - Information requested about cosmetic products.

Code of Federal Regulations, 2013 CFR

2013-04-01

... and talcum) (excluding aftershave talc). (iv) Sachets. (v) Other fragrance preparations. (5) Hair preparations (noncoloring). (i) Hair conditioners. (ii) Hair sprays (aerosol fixatives). (iii) Hair..., dressings, and other hair grooming aids. (viii) Wave sets. (ix) Other hair preparations. (6) Hair coloring...

Evaluation of the biocontrol efficacy of a Serratia marcescens strain indigenous to tea rhizosphere for the management of root rot disease in tea

PubMed Central

Mangar, Preeti; Saha, Aniruddha

2018-01-01

The aim of the present study is to evaluate plant growth promoting and biocontrol efficacy of a Serratia marcescens strain ETR17 isolated from tea rhizosphere for the effective management of root rot disease in tea. Isolated bacterial culture ETR17 showed significant level of in vitro antagonism against nine different foliar and root pathogens of tea. The phenotypic and molecular characterization of ETR17 revealed the identity of the bacterium as Serratia marcescens. The bacterium was found to produce several hydrolytic enzymes like chitinase, protease, lipase, cellulase and plant growth promoting metabolites like IAA and siderophore. Scanning electron microscopic studies on the interaction zone between pathogen and antagonistic bacterial isolate revealed severe deformities in the fungal mycelia. Spectral analyses (LC-ESI-MS, UV-VIS spectrophotometry and HPLC) and TLC indicated the presence of the antibiotics pyrrolnitrin and prodigiosin in the extracellular bacterial culture extracts. Biofilm formation by ETR17 on polystyrene surface was also observed. In vivo application of talc-based formulations prepared with the isolate ETR17 in tea plantlets under green house conditions revealed effective reduction of root-rot disease as well as plant growth promotion to a considerable extent. Viability studies with the ETR17 talc formulation showed the survivability of the isolate up to six months at room temperature. The sustenance of ETR17 (concentration of 8-9x108 cfu g-1) in the soil after the application of talc formulation was recorded by ELISA. Safety studies revealed that ETR17 did not produce hemolysin as observed in pathogenic Serratia strains. The biocontrol strain reported in this study can be used for field application in order to minimize the use of chemical fungicides for disease control in tea gardens. PMID:29466418

Success rate of medical thoracoscopy and talc pleurodesis in malignant pleurisy: A single-centre experience.

PubMed

Leemans, Joke; Dooms, Christophe; Ninane, Vincent; Yserbyt, Jonas

2018-06-01

Malignant pleurisy is associated with advanced oncological disease and dyspnoea is the most common presenting symptom. Pleurodesis is the preferred palliative and supportive treatment option, targeting symptom relief. The identification of clinical and endoscopic features that determine the success of talc pleurodesis in malignant pleurisy could guide clinical decision-making. All symptomatic patients with malignant pleurisy subjected to talc pleurodesis through medical thoracoscopy between January 2012 and December 2015 were included. Univariate and multivariate analyses were performed to identify factors associated with successful pleurodesis. Of the 155 patients, 122 (78%) were classified as having a successful pleurodesis based on clinical and radiological criteria. Factors associated with unsuccessful pleurodesis (univariate analysis) were the presence of pleural adhesions (odds ratio (OR): 0.43 (95% CI: 0.19-0.96); P = 0.04), extensive spread of pleural lesions (OR: 0.17 (95% CI: 0.05-0.59); P = 0.001), the use of systemic corticosteroids (OR: 0.28 (95% CI: 0.10-0.83); P = 0.02) and a prolonged time period between the clinical diagnosis of the pleural effusion and the moment of pleurodesis (OR: 0.14 (95% CI: 0.06-0.32); P < 0.0001). The latter being associated with failure of pleurodesis in a multivariate analysis (OR: 0.08 (95% CI: 0.01-0.25); P < 0.0001). Chest ultrasound prior to pleurodesis showed a sensitivity of 91% and a specificity of 88% in predicting the success of pleurodesis. The success rate of pleurodesis in malignant pleurisy could potentially be enhanced by correct patient selection and early referral for pleurodesis. Ultrasonic assessment of pleural adhesions and potential lung expansion prior to pleurodesis is useful in clinical decision-making. © 2018 Asian Pacific Society of Respirology.

Effectiveness and safety of outpatient pleurodesis in patients with recurrent malignant pleural effusion and low performance status

PubMed Central

Terra, Ricardo Mingarini; Teixeira, Lisete Ribeiro; Bibas, Benoit Jacques; Pego‐Fernandes, Paulo Manuel; Vargas, Francisco Suso; Jatene, Fabio Biscegli

2011-01-01

OBJECTIVES: To evaluate the effectiveness and safety of pleurodesis carried out entirely on an outpatient basis in patients with recurrent malignant pleural effusions and Karnofsky Performance Status scores ≤70. METHODS: This study was a prospective trial comprising patients with symptomatic recurrent malignant pleural effusion and Karnofsky Performance Status scores ≤70 but >30. All selected patients underwent pleural catheter placement (14 Fr) in an outpatient facility. When chest radiography revealed post‐drainage lung expansion of >90%, pleurodesis (3 g of talc) was performed. Catheters were maintained until the daily output was <100 mL/day. The patients were evaluated in the first month and every three months thereafter for fluid recurrence, the need for additional procedures, and complications. RESULTS: During the study period (January 2005 to July 2007), 64 patients (24 men, 40 women), with an average age of 61.4 years, underwent elective chest tube drainage. Primary sites of the underlying malignancy were breast (27), lung (22), and others (15). Sixty‐six pleural catheters were placed (bilaterally in 2 patients), and 52 talc pleurodesis procedures were performed. Fourteen patients had a trapped lung and were excluded from the trial. No complications were observed during catheter placement or pleurodesis. Post‐pleurodesis complications included catheter obstruction (4 patients) and empyema (1). The average drainage time was 9.9 days. The recurrence rate observed in patients that were alive 30 days after pleurodesis was 13.9% (5/36 patients). Six patients required additional procedures after the pleurodesis. The average survival time was 101 days. CONCLUSION: In this study, talc pleurodesis was safely performed in an outpatient setting with good efficacy and a reasonable complication rate, thereby avoiding hospital admission. PMID:21484035

Evaluation of the biocontrol efficacy of a Serratia marcescens strain indigenous to tea rhizosphere for the management of root rot disease in tea.

PubMed

Dhar Purkayastha, Gargee; Mangar, Preeti; Saha, Aniruddha; Saha, Dipanwita

2018-01-01

The aim of the present study is to evaluate plant growth promoting and biocontrol efficacy of a Serratia marcescens strain ETR17 isolated from tea rhizosphere for the effective management of root rot disease in tea. Isolated bacterial culture ETR17 showed significant level of in vitro antagonism against nine different foliar and root pathogens of tea. The phenotypic and molecular characterization of ETR17 revealed the identity of the bacterium as Serratia marcescens. The bacterium was found to produce several hydrolytic enzymes like chitinase, protease, lipase, cellulase and plant growth promoting metabolites like IAA and siderophore. Scanning electron microscopic studies on the interaction zone between pathogen and antagonistic bacterial isolate revealed severe deformities in the fungal mycelia. Spectral analyses (LC-ESI-MS, UV-VIS spectrophotometry and HPLC) and TLC indicated the presence of the antibiotics pyrrolnitrin and prodigiosin in the extracellular bacterial culture extracts. Biofilm formation by ETR17 on polystyrene surface was also observed. In vivo application of talc-based formulations prepared with the isolate ETR17 in tea plantlets under green house conditions revealed effective reduction of root-rot disease as well as plant growth promotion to a considerable extent. Viability studies with the ETR17 talc formulation showed the survivability of the isolate up to six months at room temperature. The sustenance of ETR17 (concentration of 8-9x108 cfu g-1) in the soil after the application of talc formulation was recorded by ELISA. Safety studies revealed that ETR17 did not produce hemolysin as observed in pathogenic Serratia strains. The biocontrol strain reported in this study can be used for field application in order to minimize the use of chemical fungicides for disease control in tea gardens.

Effect of Inoculation Techniques and Relative Humidity on the Growth of Molds on the Surfaces of Yellow Layer Cakes

PubMed Central

Fustier, Patrick; Lafond, Alain; Champagne, Claude P.; Lamarche, François

1998-01-01

Four inoculation techniques were compared for initiation of growth on cake surfaces: spot, air cabinet, spray (atomizer), and talc addition methods. Molds were isolated from commercial cakes and were identified as Aspergillus sydowii, Aspergillus ochraceus, Penicillium funiculosum, and Eurotium herbariorum. Cake surfaces were inoculated with mold spores and incubated under three equilibrium relative humidity (ERH) levels: 97, 85, and 75%. Random contamination by spores in a ventilated air cabinet was the simplest method of inoculation, but standard deviations in the inoculation rates (20% on a relative scale) were almost twice those observed with the other methods. The spot method was the most reproducible. Cake samples inoculated in the air cabinet had colony counts 10 times lower than those obtained for potato dextrose agar plates at 97% ERH, which was not the case with the spray and talc methods. Growth of molds was much slower in the samples incubated in 75% relative humidity, with all methods. Colony counts were generally similar in systems adjusted at 85 to 97% ERH but were lower for samples incubated at 75% ERH. In comparisons of the shelf life estimates obtained by the various inoculation methods, a correlation coefficient (r2) of 0.70 was obtained between the spot method and the other methods of inoculation, while talc, air cabinet, and spray shelf life data were correlated better (r2 ≈ 0.97). The spot method appeared to be the method of choice in consideration of ease of use, precision, and the ability to enable the study of the effects of the environment on mold-free shelf life as well as on the rate of growth of molds on cakes. PMID:16349479

Management of malignancy-associated pleural effusion: current and future treatment strategies.

PubMed

Marchi, Evaldo; Teixeira, Lisete R; Vargas, Francisco S

2003-01-01

Management of recurrent malignant pleural effusion, a common complication of malignancy, poses a challenge to clinicians. Although almost one century has elapsed since the introduction of the pleurodesis procedure, the ideal approach and best agent are still to be defined. Optimally, pleurodesis should be done at the bedside with a minimally invasive procedure, and suitable agents to achieve pleural symphysis should be inexpensive, available worldwide and free of adverse effects. To date, no substance completely fulfills these requirements. Silver nitrate should be considered for pleurodesis because of its low cost and ease of handling. Although talc has been used most frequently to induce pleurodesis, reports of death due to acute respiratory failure have raised concerns about the safety of this agent. Tetracycline, an effective alternative used in the past, is no longer commercially available. This agent has been substituted with derivatives of tetracycline, such as minocycline and doxycycline with success rates similar to those with tetracycline. Several antineoplastic agents have been injected into the pleural space with the aim of producing pleural symphysis, the most representative of this group being bleomycin. Recent knowledge of the molecular mechanisms involved in pleural inflammation has brought into focus new substances, such as transforming growth factor beta and vascular endothelial growth factor, which may be used as pleurodesis agents in the future. Nevertheless, more studies are necessary to better define the potential of these substances in the induction of pleural symphysis.Ideally, a sclerosing agent should be cost-effective, available worldwide and easily administered. Talc will probably stand as the preferred agent to be used for pleurodesis in malignant pleural effusion because of its efficacy, easy manipulation and handling. However, further investigation is necessary to minimize adverse effects related to talc.

Diagnosis and treatment of malignant pleural effusion: a systematic literature review and new approaches.

PubMed

Lombardi, Giuseppe; Zustovich, Fable; Nicoletto, Maria Ornella; Donach, Martin; Artioli, Grazia; Pastorelli, Davide

2010-08-01

Malignant pleural effusion is a frequent complication in many types of tumors, and its presence indicates short expected survival. This review updates the current knowledge about diagnosis and management of malignant pleural effusion. In recent years, progress has been made in diagnosis through the use of new pathologic and radiologic approaches, such as the introduction of positron emission tomography-computed tomography, immunohistochemical marker combinations, and genetic studies to identify malignant cells. Treatment is always palliative. New promising drugs have been tested, but, awaiting randomized studies, talc pleurodesis is still the treatment of choice, although doubts remain about its safety. A long-term indwelling pleural catheter could be a valid alternative to talc pleurodesis in selected patients with trapped lung syndrome (a lung that fails to reexpand after drainage of pleural effusion) and short life expectancy. However, the correct treatment depends on several factors such as performance status, expected survival, presence of lung reexpansion following pleural drainage and comorbidities.

21 CFR 82.2051 - Lakes (Ext. D&C).

Code of Federal Regulations, 2010 CFR

2010-04-01

..., titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or on any combination of... is a salt in which is combined the basic radical sodium, potassium, barium, or calcium; or (ii) a... color with the basic radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium. (2...

21 CFR 82.2051 - Lakes (Ext. D&C).

Code of Federal Regulations, 2012 CFR

2012-04-01

..., titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or on any combination of... is a salt in which is combined the basic radical sodium, potassium, barium, or calcium; or (ii) a... color with the basic radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium. (2...

21 CFR 82.2051 - Lakes (Ext. D&C).

Code of Federal Regulations, 2013 CFR

2013-04-01

..., titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or on any combination of... is a salt in which is combined the basic radical sodium, potassium, barium, or calcium; or (ii) a... color with the basic radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium. (2...

21 CFR 82.2051 - Lakes (Ext. D&C).

Code of Federal Regulations, 2014 CFR

2014-04-01

..., titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or on any combination of... is a salt in which is combined the basic radical sodium, potassium, barium, or calcium; or (ii) a... color with the basic radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium. (2...

21 CFR 82.2051 - Lakes (Ext. D&C).

Code of Federal Regulations, 2011 CFR

2011-04-01

..., titanium dioxide, zinc oxide, talc, rosin, aluminum benzoate, calcium carbonate, or on any combination of... is a salt in which is combined the basic radical sodium, potassium, barium, or calcium; or (ii) a... color with the basic radical sodium, potassium, aluminum, barium, calcium, strontium, or zirconium. (2...

Waste-wood-derived fillers for plastics

Treesearch

Brent English; Craig M. Clemons; Nicole Stark; James P. Schneider

1996-01-01

Filled thermoplastic composites are stiffer, stronger, and more dimensionally stable than their unfilled counterparts. Such thermoplastics are usually provided to the end-user as a precompounded, pelletized feedstock. Typical reinforcing fillers are inorganic materials like talc or fiberglass, but materials derived from waste wood, such as wood flour and recycled paper...

7 CFR 51.1241 - Damage.

Code of Federal Regulations, 2010 CFR

2010-01-01

... which have been broken to the extent that the kernel within is plainly visible without minute... discoloration beneath, but the peanut shall be judged as it appears with the talc. (c) Kernels which are rancid or decayed. (d) Moldy kernels. (e) Kernels showing sprouts extending more than one-eighth inch from...

21 CFR 137.350 - Enriched rice.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Enriched rice. 137.350 Section 137.350 Food and... Related Products § 137.350 Enriched rice. (a) The foods for which definitions and standards of identity are prescribed by this section are forms of milled rice (except rice coated with talc and glucose and...

Measuring the Hardness of Minerals

ERIC Educational Resources Information Center

Bushby, Jessica

2005-01-01

The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

Use of centrifugal-gravity concentration for rejection of talc and recovery improvement in base-metal flotation

NASA Astrophysics Data System (ADS)

Klein, Bern; Altun, Naci Emre; Ghaffari, Hassan

2016-08-01

The possibility of using a centrifugal-gravity concentrator to reject Mg-bearing minerals and minimize metal losses in the flotation of base metals was evaluated. Sample characterization, batch scoping tests, pilot-scale tests, and regrind-flotation tests were conducted on a Ni flotation tailings stream. Batch tests revealed that the Mg grade decreased dramatically in the concentrate products. Pilot-scale testing of a continuous centrifugal concentrator (Knelson CVD6) on the flotation tailings revealed that a concentrate with a low mass yield, low Mg content, and high Ni upgrade ratio could be achieved. Under optimum conditions, a concentrate at 6.7% mass yield was obtained with 0.85% Ni grade at 12.9% Ni recovery and with a low Mg distribution (1.7%). Size partition curves demonstrated that the CVD also operated as a size classifier, enhancing the rejection of talc fines. Overall, the CVD was capable of rejecting Mg-bearing minerals. Moreover, an opportunity exists for the novel use of centrifugal-gravity concentration for scavenging flotation tailings and/or after comminution to minimize amount of Mg-bearing minerals reporting to flotation.

Inhibition of lymphocyte proliferation and antibody production in vitro by silica, talc, bentonite or Corynebacterium parvum: involvement of peroxidative processes.

PubMed

Hoffeld, J T

1983-05-01

This study was undertaken to determine whether and by what means particles which induce granulomata in vivo can affect murine spleen lymphoproliferative and antibody responses in vitro. Particles of silica, talc, Bentonite or C. parvum cells inhibited lipopolysaccharide- or concanavalin A-stimulated proliferation and sheep red blood cell-induced antibody response in vitro. The inhibition required at least 48 hours exposure of the cells to the particles. The late onset of inhibition and its reproducibility at different cell or mitogen concentrations implicated particle-induced injury to both phagocytes and lymphocytes. Either alpha-tocopherol or 2-mercaptoethanol prevented the particle-induced inhibition of spleen cell responses. alpha-Tocopherol and 2-mercaptoethanol have in common the capacity to protect cells against membrane lipid peroxidation. The inhibitory peroxidative process(es) implicated by these studies are most likely attributable to: (a) stimulation of oxidative metabolism of phagocytic cells by particles; and (b) iron-catalyzed peroxidation directly by the particles. These data may be relevant in understanding the pathogenesis of and devising therapeutic approaches toward various granulomatous conditions.

Development of carrier-based formulation of root endophyte Piriformospora indica and its evaluation on Phaseolus vulgaris L.

PubMed

Tripathi, Swati; Das, Aparajita; Chandra, Anil; Varma, Ajit

2015-02-01

Endophytic fungi are plant beneficial rhizospheric microorganisms often applied as bioinoculants for enhanced and disease-free crop production. The objectives of the present work were to develop a carrier-based formulation of root endophyte Piriformospora indica as a bioinoculant. Powder formulation of four different carrier materials viz., talcum powder, clay, sawdust and bioboost (organic supplement) were evaluated and a talc-based formulation was optimized for a longer shelf life with respect to microbial concentration, storage temperature and biological activity. Finally the effect of optimized talc formulation on plant productivity was determined. The application dosages were optimized by studies on plant growth parameters of Phaseolus vulgaris L. plants under green house conditions. Five percent formulation (w/w) of talcum powder was observed to be the most stable at 30 °C with 10(8) CFU g(-1) and effective for a storage period of 6 months. The application of this optimized formulation resulted in increase of growth parameters of P. vulgaris L. and better adaptation of plants under green house conditions.

Power Doppler evaluation of joint effusions: investigation in a rabbit model.

PubMed

Strouse, P J; DiPietro, M A; Teo, E L; Doi, K; Chrisp, C E

1999-08-01

To study the power Doppler findings of septic arthritis and noninfectious synovitis in an animal model. The right knees of 10 rabbits were inoculated with an aqueous suspension of Staphylococcus aureus. The right knees of 5 rabbits were injected with talc suspension. The right knees of 5 rabbits were injected with saline. All 20 left knees were injected with saline. Serial power Doppler images were obtained using constant-imaging parameters. Images were reviewed by blinded observers who assessed for increased power Doppler signal. All 10 knees inoculated with S. aureus developed septic arthritis. Each infected rabbit knee demonstrated increased signal on power Doppler on at least one examination, ranging from 1-6 days after inoculation. Only 23 of 45 examinations of infected knees were unequivocally positive by power Doppler on examinations performed 1 to 6 days after inoculation. No knee with talc synovitis demonstrated increased power Doppler signal. No control knee demonstrated increased power Doppler signal. Increased power Doppler signal may be seen with septic arthritis; however, its intensity and timing may vary from subject to subject. A normal power Doppler examination does not exclude septic arthritis.

Occurrence and Mineralogical Characteristics of Tremolite Asbestos Occurred in Boryeong area, Chungnam, South Korea

NASA Astrophysics Data System (ADS)

Yoon, K.; Hwang, J.; Oh, J.; Lee, H.

2009-12-01

Abandoned tremolite mines, which had been exploited for several decades since 1930, are distributed in Boryeong, Chungnam. It is known that tremolite asbestos is approximately 100 times more harmful than chrysotile asbestos. Recently, it become a regional social problem because lung disease (mesothelioma and lung cancer) suspect patients are largely found among the residents of the mining area. Therefore, Korean government making every endeavor to remove asbestos risk in the area. However, there is insufficiency geological and mineralogical studies for tremolite asbestos. In the present study, the occurrence and mineralogical characteristics of tremolite asbestos were studied using polarization microscope, XRD, XRF, EPMA, SEM and TEM. Mica-schist of precambrian metasedimentary rock, which is widely distributed in the area, is the host rock of tremolite deposits. The rocks are largely disturbed by faults and folds, and shows sudden changes in strike and slope of strata. Tremolite ore bodies, which show relatively light colored, mainly occur as stratiform or veinlet and some occurs in brecciated rock fragments. Tremolite is a major asbestos mineral, and chrysotile, talc, mica, chlorite and quartz occurs as associated minerals. Considerable amount of ore containing pure tremolite is found, and ores having mineral assemblages of tremolite+talc, tremolite+quartz and chrysotile+talc also occurs. From optical microscope observations, most tremolites are asbestos from that meets to the criterion (length > 5 μm, diameter < 3 μm, aspect ratio > 3:1) defined by the international organization (WHO, ILO), but non-asbestos form tremolites are also included. Most asbestos form tremolites have the size range of 1.0-2.0 μm width and 5-10 μm length. The length can be shorten with crushing experiments, but the width remains unchanged. Non-asbestos form hardly change to asbestos form by mechanical crushing. From comprehensive studies for geological occurrence and mineral assemblage, it is considered that tremolite is formed within Mg-rich strata, which is intercalated in precambrian mica-schist, by hydrothermal alteration associated with faults movements.

Video-assisted thoracoscopic bullectomy and talc poudrage for spontaneous pneumothoraces: effect on short-term lung function.

PubMed

Dubois, Luc; Malthaner, Richard A

2010-12-01

We measured lung function before and after video-assisted thoracoscopic apical bullectomy and talc poudrage in patients with spontaneous pneumothoraces. Seventy-two patients were prospectively followed up for 12 months. The indications for surgery were recurrent pneumothoraces (n = 58), bilateral pneumothoraces (n = 8), and persistent air leak (n = 6). There were 46 males and 26 females with mean age of 29 years (range 15-61 years). The results were analyzed using paired t tests. There were no recurrences. There were 4 complications (5.6%): 1 wound infection, 1 case of pneumonia, and 2 persistent air leaks each lasting 1 week. There were no conversions to open surgery. Preoperative and 6-month pulmonary function test results were available on 41 patients, and 35 patients completed 12-month pulmonary function tests. Twelve-month values (mean percent ± SD) were as follows: Forced expiratory volume in 1 second fell from 95 ± 19 to 89 ± 16 (P = .02); forced expiratory volume in 1 second/forced vital capacity ratio was unchanged, 95 ± 12 versus 94 ± 13 (P = .9); total lung capacity fell from 106 ± 19 to 98 ± 12 (P = 0.002); vital capacity fell from 100 ± 22 to 96 ± 16 (P = .05); residual volume fell from 126 ± 32 to 107 ± 29 (P = .002); and diffusion capacity for carbon monoxide corrected for alveolar volume was unchanged, 88 ± 15 versus 91 ± 17 (P = .07). Flow rates and diffusion capacities were preserved, but lung volumes were slightly reduced at 1 year. Video-assisted thoracoscopic apical bullectomy and talc poudrage is an effective treatment for spontaneous pneumothoraces with a low complication rate and recurrence rate and only minor changes in pulmonary function at 1 year. Copyright © 2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

The Development of a Hydroperm (Trademark) Microfiltration System for the Treatment of ’MUST’ Hospital Wastewater Effluents.

DTIC Science & Technology

1977-10-01

by pH extremes, and nonionic surfactants have been identified as bad actors" in causing membrane fouling1. Also the Hydroperm filtration technique...Talc 9. Soil (kaolinite) 10. Silver Chloride 11. Hair oil 12. Hair gel 13. Vegetable oil 14. Grease (Lard) 15. Toothpaste 16. Hair Shampoo 17

Training the Foot Soldiers of Inquiry: Development and Evaluation of a Graduate Teaching Assistant Learning Community

ERIC Educational Resources Information Center

Linenberger, Kimberly; Slade, Michael C.; Addis, Elizabeth A.; Elliott, Emily R.; Mynhardt, Glené; Raker, Jeffrey R.

2014-01-01

As part of a Howard Hughes Program for Innovation in Science Education grant at Iowa State University, a series of interdisciplinary graduate teaching assistant learning communities (TALC) were developed. The purpose of these communities was to create an environment to facilitate teaching assistants' pedagogical development and training to enhance…

[Crystalline retinopathy].

PubMed

Rasquin, F

2007-01-01

Crystalline retinopathy is characterized by intraretinal crystalline deposits that, according to their etiology, can be localized in the macular area or, indeed, be found in the entire retina. These deposits can be associated or not to visual loss and electrophysiological perturbations. Among the toxic drugs leading to this retinopathy are tamoxifen, canthaxanthine, methoxyflurane, talc and nitrofurantoin. A detailed description of tamoxifen and canthaxanthine toxicity is reported in this chapter.

Arasin in endrin treatments to protect Douglas-fir seed from deer mice.

Treesearch

G.L. Crouch; M.A. Radwan

1972-01-01

In laboratory bioassays, coating with endrin reduced consumption of Douglas-fir seed by deer mice. Coating with Arasan did not lower seed consumption, but endrin plus Arasan reduced feeding to levels comparable with endrin alone. Substitution of talc for Arasan produced similar results. Endrin had little effect on seed germination, but addition of Arasan caused a...

ERS task force statement: diagnosis and treatment of primary spontaneous pneumothorax.

PubMed

Tschopp, Jean-Marie; Bintcliffe, Oliver; Astoul, Philippe; Canalis, Emilio; Driesen, Peter; Janssen, Julius; Krasnik, Marc; Maskell, Nicholas; Van Schil, Paul; Tonia, Thomy; Waller, David A; Marquette, Charles-Hugo; Cardillo, Giuseppe

2015-08-01

Primary spontaneous pneumothorax (PSP) affects young healthy people with a significant recurrence rate. Recent advances in treatment have been variably implemented in clinical practice. This statement reviews the latest developments and concepts to improve clinical management and stimulate further research.The European Respiratory Society's Scientific Committee established a multidisciplinary team of pulmonologists and surgeons to produce a comprehensive review of available scientific evidence.Smoking remains the main risk factor of PSP. Routine smoking cessation is advised. More prospective data are required to better define the PSP population and incidence of recurrence. In first episodes of PSP, treatment approach is driven by symptoms rather than PSP size. The role of bullae rupture as the cause of air leakage remains unclear, implying that any treatment of PSP recurrence includes pleurodesis. Talc poudrage pleurodesis by thoracoscopy is safe, provided calibrated talc is available. Video-assisted thoracic surgery is preferred to thoracotomy as a surgical approach.In first episodes of PSP, aspiration is required only in symptomatic patients. After a persistent or recurrent PSP, definitive treatment including pleurodesis is undertaken. Future randomised controlled trials comparing different strategies are required. Copyright ©ERS 2015.

Talc based exopolysaccharides formulation enhancing growth and production of Hellianthus annuus under saline conditions.

PubMed

Tewari, S; Arora, K

2014-12-24

Stress tolerating strain of Pseudomonas aeruginosa PF07 possessing plant growth promoting activity was screened for the production of exopolysaccharides (EPS). EPS production was monitored in the cell free culture supernatant (CFCS) and extracted EPS was further purified by thin layer chromatography. EPS producing cells were taken to design talc based formulation and its efficacy was checked on oilseed crop sunflower (Hellianthus annuus), under in vivo saline conditions (soil irrigated with 125 mM of saline water). Application of bioformulation significantly enhanced the yield and growth attributes of the plant in comparison to control (untreated seeds) under stress and non—stress conditions. Germination rate, plant length, dry weight and seed weight increased remarkably. The above findings suggest the application and benefits of utilizing EPS formulation in boosting early seedling emergence, enhancing plant growth parameters, increasing seed weight and mitigating stress in saline affected regions. Such bioformulation may enhance RAS/RT (Root Adhering Soil to Root Tissue ratio), texture of the soil, increase porosity, improve uptake of nutrients, and hence may be considered as commercially important formulation for renovation of stressed sites and enhancing plant growth.

Role of different compatibilizing approaches on the microstructure and mechanical properties of polypropylene/talc composites

NASA Astrophysics Data System (ADS)

Homayounfar, S. Z.; Bagheri, R.

2014-05-01

Since in a highly filled polymer, a major problem arises from non-uniformity of properties due to the poor dispersion of filler, the application of coupling agents have been directed to overcome this problem and also to enhance the mechanical performance of the composites by improving the adhesion at the interface. In this study, a comparison between two major coupling approaches is conducted: 1) Using PPgMA as a kind of compatibilizer which changes the nature of the matrix, 2) Using titanate coupling agent which takes action at the interface and reacts with hydroxyl groups at the inorganic filler surface, resulting in the formation of monomolecular layer on the inorganic surface to increase compatibility of filler/matrix interface. The comparison is made based on the mechanical properties of the composites by means of elastic modulus, yield stress, impact strength and percentage of strain-to-fracture and evaluation of their effects on both the dispersion and adhesion of talc plates in the matrix through the microscopy. Transmission optical microscopy (TOM) and scanning electron microscopy (SEM) are used to observe the deformation micromechanism and the fracture surface of the composites, respectively.

Mössbauer study of Brazilian soapstone

NASA Astrophysics Data System (ADS)

Gonçalves, M. A.; de Jesus Filho, M. F.; Garg, V. K.

1991-11-01

Steatite mineral rocks, soapstone, have been studied by X-ray diffraction, optical microscopic analysis (modal analysis), electron probe micro analysis and Mössbauer spectroscopy for characterization, mineral percentages and chemical composition. Mössbauer spectra show both, magnetic interactions corresponding to magnetite and doublets corresponding to talc. chlorite, dolomite and tremolite. The temperature dependence of the quadrupole splitting in dolomite has been explained in terms of crystal field interaction.

Metamorphic assemblages and the direction of flow of metamorphic fluids in four instances of serpentinization

USGS Publications Warehouse

Barnes, I.; Rapp, J.B.; O'Neil, J.R.; Sheppard, R.A.; Gude, A.J.

1972-01-01

Fluids related to Serpentinization are of at least three types. The first reported (Barnes and O'Neil, 1969) is a fluid of local meteoric origin, the chemical and thermodynamic properties of which are entirely controlled by olivine, orthopyroxene, brucite, and serpentine reactions. It is a Ca+2-OH-1 type and is shown experimentally to be capable of reacting with albite to yield calcium hydroxy silicates. Rodingites may form where the Ca+2-OH-1 type waters flow across the ultramafic contact and react with siliceous country rock. The second type of fluid has its chemical composition largely controlled before it enters the ultramafic rocks, but reactions within the ultramafic rocks fix the thermodynamic properties by reactions of orthopyroxene, olivine, calcite, brucite, and serpentine. The precipitation of brucite from this fluid clearly shows that fluid flow allows reaction products to be deposited at a distance from the point of solution. Thus, textural evidence for volume relations during Serpentinization may not be valid. The third type of fluid has its chemical properties fixed in part before the reactions with ultramafic rocks, in part by the reactions of orthopyroxene, olivine, and serpentine and in part by reactions with siliceous country rock at the contact. The reactions of the ultramafic rock and country rock with the fluid must be contemporaneous and require flow to be along the contact. This third type of fluid is grossly supersaturated with talc and tremolite, both found along the contact. The occurrence of magadiite, kenyaite, mountainite, and rhodesite along the contact is probably due to a late stage low-temperature reaction of fluids of the same thermodynamic properties as those that formed the talc and tremolite at higher temperatures. Oxygen isotope analyses of some of these minerals supports this conclusion. Rodingites form from Ca+2-rich fluids flowing across the contact; talc and tremolite form from silica-rich fluids flowing along the contact. Isotopic analyses of the fluids indicate varied origins including unaltered local meteoric water and connate water. Complexion Spring water may be a sample of only slightly altered Jurassic or Cretaceous sea water. ?? 1972 Springer-Verlag.

Time-resolved remote Raman study of minerals under supercritical CO2 and high temperatures relevant to Venus exploration.

PubMed

Sharma, Shiv K; Misra, Anupam K; Clegg, Samuel M; Barefield, James E; Wiens, Roger C; Acosta, Tayro

2010-07-13

We report time-resolved (TR) remote Raman spectra of minerals under supercritical CO(2) (approx. 95 atm pressure and 423 K) and under atmospheric pressure and high temperature up to 1003 K at distances of 1.5 and 9 m, respectively. The TR Raman spectra of hydrous and anhydrous sulphates, carbonate and silicate minerals (e.g. talc, olivine, pyroxenes and feldspars) under supercritical CO(2) (approx. 95 atm pressure and 423 K) clearly show the well-defined Raman fingerprints of each mineral along with the Fermi resonance doublet of CO(2). Besides the CO(2) doublet and the effect of the viewing window, the main differences in the Raman spectra under Venus conditions are the phase transitions, the dehydration and decarbonation of various minerals, along with a slight shift in the peak positions and an increase in line-widths. The dehydration of melanterite (FeSO(4).7H(2)O) at 423 K under approximately 95 atm CO(2) is detected by the presence of the Raman fingerprints of rozenite (FeSO(4).4H(2)O) in the spectrum. Similarly, the high-temperature Raman spectra under ambient pressure of gypsum (CaSO(4).2H(2)O) and talc (Mg(3)Si(4)O(10)(OH)(2)) indicate that gypsum dehydrates at 518 K, but talc remains stable up to 1003 K. Partial dissociation of dolomite (CaMg(CO(3))(2)) is observed at 973 K. The TR remote Raman spectra of olivine, alpha-spodumene (LiAlSi(2)O(6)) and clino-enstatite (MgSiO(3)) pyroxenes and of albite (NaAlSi(3)O(8)) and microcline (KAlSi(3)O(8)) feldspars at high temperatures also show that the Raman lines remain sharp and well defined in the high-temperature spectra. The results of this study show that TR remote Raman spectroscopy could be a potential tool for exploring the surface mineralogy of Venus during both daytime and nighttime at short and long distances.

Structural changes of cytochrome c(552) from Thermus thermophilus adsorbed on anionic and hydrophobic surfaces probed by FTIR and 2D-FTIR spectroscopy.

PubMed

Lecomte, S; Hilleriteau, C; Forgerit, J P; Revault, M; Baron, M H; Hildebrandt, P; Soulimane, T

2001-03-02

The structural changes of cytochrome c(552) bound to anionic and hydrophobic clay surfaces have been investigated by Fourier transform infrared spectroscopy. Binding to the anionic surface of montmorillonite is controlled by electrostatic interactions since addition of electrolyte (0.5 mol L(-1) KCl) causes desorption of more than 2/3 of the protein molecules. Electrostatic binding occurs through the back side of the protein (i.e., remote from the heme site) and is associated only with subtle changes of the secondary structure. In contrast, adsorption to the hydrophobic surface of talc leads to a decrease in alpha-helical structure by ca. 5% and an increase in beta-sheet structure by ca. 6%. These structural changes are attributed to a hydrophobic region on the front surface of cytochrome c(552) close to the partially exposed heme edge. This part on the protein surface is identified as the interaction domain for talc and most likely also serves for binding to the natural reaction partner, a ba(3)-oxidase. Fourier transform infrared spectra of cytochrome c(552) and the clay-cytochrome c(552) complexes have been measured as a function of time following dissolution and suspension in deuterated buffer, respectively. A two-dimensional correlation analysis was applied to these spectra to investigate the dynamics of the structural changes in the protein. For both complexes, adsorption and subsequent unfolding processes in the binding domains are faster than the time resolution of the spectroscopic experiments. Thus, the processes that could be monitored are refolding of peptide segments and side chain rearrangements following the adsorption-induced perturbation of the protein structure and the solvation of the adsorbed protein. In each case, side chain alterations of solvent-exposed tyrosine, aspartate, and glutamate residues were observed. For the cytochrome c(552)-talc complex, these changes are followed by a slow refolding of the peptide chain in the binding domain and, subsequently, a further H/D exchange of amide group protons.

Constraining friction, dilatancy and effective stress with earthquake rates in the deep crust

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Thomas, A.; Burgmann, R.; Shelly, D. R.

2015-12-01

Similar to their behavior on the deep extent of some subduction zones, families of recurring low-frequency earthquakes (LFE) within zones of non-volcanic tremor on the San Andreas fault in central California show strong sensitivity to stresses induced by the tides. Taking all of the LFE families collectively, LFEs occur at all levels of the daily tidal stress, and are in phase with the very small, ~200 Pa, shear stress amplitudes while being uncorrelated with the ~2 kPa tidal normal stresses. Following previous work we assume LFE sources are small, persistent regions that repeatedly fail during shear within a much larger scale, otherwise aseismically creeping fault zone and that the correlation of LFE occurrence reflects modulation of the fault creep rate by the tidal stresses. We examine the predictions of laboratory-observed rate-dependent dilatancy associated with frictional slip. The effect of dilatancy hardening is to damp the slip rate, so high dilatancy under undrained pore pressure reduces modulation of slip rate by the tides. The undrained end-member model produces: 1) no sensitivity to the tidal normal stress, as first suggested in this context by Hawthorne and Rubin [2010], and 2) fault creep rate in phase with the tidal shear stress. Room temperature laboratory-observed values of the dilatancy and friction coefficients for talc, an extremely weak and weakly dilatant material, under-predict the observed San Andreas modulation at least by an order of magnitude owing to too much dilatancy. This may reflect a temperature dependence of the dilatancy and friction coefficients, both of which are expected to be zero at the brittle-ductile transition. The observed tidal modulation constrains the product of the friction and dilatancy coefficients to be at most 5 x 10-7 in the LFE source region, an order of magnitude smaller than observed at room temperature for talc. Alternatively, considering the predictions of a purely rate-dependent talc friction would constrain the ambient effective normal stress to be no more than 40 kPa. In summary, for friction models that have both rate-dependent strength and dilatancy, the observations require intrinsic weakness, low dilatancy, and lithostatic pore fluid pressures.

Geochemistry, Metamorphic Assemblages, and Microstructures in Small Ultramafic Bodies from the Northern Nason Terrane, Washington

NASA Astrophysics Data System (ADS)

Magloughlin, J. F.

2014-12-01

Ultramafic bodies ranging from <1 to 2500 m in length occur in multiple settings across the northern part of the Nason Terrane in the North Cascade Mountains of Washington State. Within the Wenatchee Ridge Orthogneiss (WRO) the bodies are approximately equidimensional, ranging from dm-scale metasomatized lenses up to an exposed diameter of (typically) approximately 40 m. Some bodies are completely serpentinized, but others include dunite, harzburgite, and rare seams of pyroxenite. Many are rimmed by blackwall (talc, phlogopite, tremolite, chlorite, serpentine) coinciding with the Late Cretaceous metamorphism. The Napeequa Ultramafic Body (NUB), cut through and well exposed by the Napeequa River west of Lake Wenatchee, is within the White River Shear Zone (WRSZ, Magloughlin & McEwan, 1988). Though highly variable, it consists of dunite and peridotite and is variably serpentinized with common Mg-amphibole. Assemblages include serp+carb+chl+talc+opq and suggest upper greenschist to low amphibolite facies overprinting. Rare high-strain zones resemble relict pseudotachylyte veins. More common are ultramylonitic zones with olivine grain sizes of <5 microns, suggesting terrane-boundary paleostresses of >250 MPa. The Nine Mile Creek Ultramafic Body (NMCUB) and Grave Ultramafic Body (GUB) are the largest bodies outside of the White River Shear Zone, and are approximately 300 m and 800 long, respectively. Both are characterized by ol+talc+amph along with chlorite pseudomorphs, commonly cut by <40 micron thick ribbons of calcite, and rarely containing Si defined by chromite. These tectonites contain fine-grained olivine, but post-deformational, metamorphic cummingtonite and tremolite. In both bodies, a moderate to strong foliation is developed. It is suggested both bodies are retrogressed garnet peridotites. An interesting problem is why the possible retrogressed garnet peridotite bodies are present south of the WRSZ and surrounded by the metatonalites of the WRO, but none are present within the WRSZ. The extreme variability of the ultramafic bodies south of the WRSZ, and their presence within the WRO pluton, suggests a possible stoping mechanism from a heterogeneous ultramafic-rich sole of the WRSZ, or a possibly now-eroded splay of that shear zone.

Department of Defense Dictionary of Military and Associated Terms

DTIC Science & Technology

2008-05-30

cargo on board a ship for the purpose of accomplishing en route maintenance and security. supersonic — Of or pertaining to speed ...information systems TAK cargo ship T- AKR fast logistics ship TALCE tanker airlift control element Appendix A As Amended Through 30 May 2008...priorities committee — (*) A committee set up to determine the priorities of passengers and cargo . air raid reporting control ship — (*) A

Smoking, occupational exposure to rubber, and lung cancer.

PubMed Central

Zhang, Z F; Yu, S Z; Li, W X; Choi, B C

1989-01-01

A cohort of 1624 employees (957 men, 667 women) in a rubber factory in Shanghai have been followed up since 1972 and their 12 year mortality experience is presented. The relative risk of lung cancer for smokers was 8.5 for men and 11.4 for women and for rubber workers exposed to curing agents or talc powder 3.2 for men and 4.6 for women. PMID:2920138

Tanker Airlift Control Elements (TALCEs) and Contingency Response Units (CRUs): Does Air Force Operational Doctrine Need to Change?

DTIC Science & Technology

2001-06-01

34 Table 4. Pros and Cons of Alternate Solutions ................................................................. 43 viii Abstract...the best structure for the Air Force goes beyond the scope of this paper. The table below summarizes the pros and cons of the three alternate...solutions presented. Table 4. Pros and Cons of Alternate Solutions Solution Pros Cons No CRU Centralized management and training, few MOG limitations

Development of Design Review Procedures for Army Air Pollution Abatement Projects. Volume I.

DTIC Science & Technology

1980-07-01

Sanding machines 3.25 Silica 2.75 Soap 2.25 Soapstone 2.25 Starch 2.25 Sugar 2.25 Talc 2.25 Tobacco 3.5 Wood 3.5 2-107 TABLE 2-9 RECOMMENDED MAXIMUM...about 1,600 and the motor bhp is 44. According to Table 4-12, the motor rpm should be 1,800; hence, the corresponding price is about $600. If a magnetic

Volatile-bearing phases in carbonaceous chondrites: Compositions, modal abundance, and reaction kinetics

NASA Technical Reports Server (NTRS)

Ganguly, Jibamitra

1990-01-01

The spectral and density characteristics of Phobos and Deimos (the two small natural satellites of Mars) strongly suggest that a significant fraction of the near-earth asteroids are made of carbonaceous chondrites, which are rich in volatile components and, thus, could serve as potential resources for propellants and life supporting systems in future planetary missions. However, in order to develop energy efficient engineering designs for the extraction of volatiles, knowledge of the nature and modal abundance of the minerals in which the volatiles are structurally bound and appropriate kinetic data on the rates of the devolatilization reactions is required. Theoretical calculations to predict the modal abundances and compositions of the major volatile-bearing and other mineral phases that could develop in the bulk compositions of C1 and C2 classes (the most volatile rich classes among the carbonaceous chondrites) were performed as functions of pressure and temperature. The rates of dehydration of talc at 585, 600, 637, and 670 C at P(total) = 1 bar were determine for the reaction: Talc = 3 enstatite + quartz + water. A scanning electron microscopic study was conducted to see if the relative abundance of phases can be determined on the basis of the spectral identification and x ray mapping. The results of this study and the other studies within the project are discussed.

Asbestos in commercial cosmetic talcum powder as a cause of mesothelioma in women

PubMed Central

Gordon, Ronald E; Fitzgerald, Sean; Millette, James

2014-01-01

Background: Cosmetic talcum powder products have been used for decades. The inhalation of talc may cause lung fibrosis in the form of granulomatose nodules called talcosis. Exposure to talc has also been suggested as a causative factor in the development of ovarian carcinomas, gynecological tumors, and mesothelioma. Purpose: To investigate one historic brand of cosmetic talcum powder associated with mesothelioma in women. Methods: Transmission electron microscope (TEM) formvar-coated grids were prepared with concentrations of one brand of talcum powder directly, on filters, from air collections on filters in glovebox and simulated bathroom exposures and human fiber burden analyses. The grids were analyzed on an analytic TEM using energy-dispersive spectrometer (EDS) and selected-area electron diffraction (SAED) to determine asbestos fiber number and type. Results: This brand of talcum powder contained asbestos and the application of talcum powder released inhalable asbestos fibers. Lung and lymph node tissues removed at autopsy revealed pleural mesothelioma. Digestions of the tissues were found to contain anthophyllite and tremolite asbestos. Discussion: Through many applications of this particular brand of talcum powder, the deceased inhaled asbestos fibers, which then accumulated in her lungs and likely caused or contributed to her mesothelioma as well as other women with the same scenario. PMID:25185462

Preservation in microbial mats: mineralization by a talc-like phase of a fish embedded in a microbial sarcophagus

NASA Astrophysics Data System (ADS)

Iniesto, Miguel; Zeyen, Nina; López-Archilla, Ana; Bernard, Sylvain; Buscalioni, Ángela; Guerrero, M. Carmen; Benzerara, Karim

2015-09-01

Microbial mats have been repeatedly suggested to promote early fossilization of macroorganisms. Yet, experimental simulations of this process remain scarce. Here, we report results of 5 year-long experiments performed onfish carcasses to document the influence of microbial mats on mineral precipitation during early fossilization. Carcasses were initially placed on top of microbial mats. After two weeks, fishes became coated by the mats forming a compact sarcophagus, which modified the microenvironment close to the corpses. Our results showed that these conditions favoured the precipitation of a poorly crystalline silicate phase rich in magnesium. This talc-like mineral phase has been detected in three different locations within the carcasses placed in microbial mats for more than 4 years: 1) within inner tissues, colonized by several bacillary cells; 2) at the surface of bones of the upper face of the corpse buried in the mat; and 3) at the surface of several bones such as the dorsal fin which appeared to be gradually replaced by the Mg-silicate phase. This mineral phase has been previously shown to promote bacteria fossilization. Here we provide first experimental evidence that such Mg-rich phase can also be involved in exceptional preservation of animals.

Isolation of animal viruses from farm livestock waste, soil and water.

PubMed Central

Derbyshire, J. B.; Brown, E. G.

1978-01-01

Ten porcine enteroviruses, 2 porcine adenoviruses and 1 coronavirus were isolated directly from 32 samples of slurry collected from a pig fattening house. Concentration of the same samples by adsorption with the polyelectrolyte PE-60 yielded 24 porcine enteroviruses and 3 porcine adenoviruses. A porcine enterovirus was isolated, following PE-60 concentration, from 1 to 6 slurry samples from a sow farrowing house. No virus was isolated from 12 samples of slurry from dairy cows nor from 6 slurry samples from a calf-rearing unit. A porcine enterovirus was isolated from soil samples, after concentration with PE-60, collected 1, 2 and 8 days after pig slurry was spread on hay stubble. Two porcine enteroviruses were isolated by membrane filtration from 26 samples of surface run-off from land on which pig slurry was routinely spread, and 2 bovine enteroviruses were isolated from cattle feedlot run-off after adsorption to layers of talc and celite followed by hydroextraction. A porcine enterovirus was also isolated from 1 of 33 samples of surface water collected on farms on which pig slurry was routinely spread on the land, but no virus was isolated from 36 samples of ground water from the same farms. The surface water and ground water samples were concentrated by talc-celite adsorption and hydroextraction. PMID:100551

The effects of serpentinization on Mg isotopes in Mid-Atlantic ridge peridotite

NASA Astrophysics Data System (ADS)

Wimpenny, J.; Harvey, J.; Yin, Q.

2012-12-01

The magnesium isotope composition of the Earth's mantle [1], and bulk estimates for upper crustal rocks [2] overlap with values obtained from chondritic meteorites [1], suggesting broad scale homogeneity of δ26Mg on Earth. By way of contrast, weathering of continental crust results in significant fractionation of Mg isotopes [3]. Negative δ26Mg in riverine and groundwater fluxes suggest that the lighter isotopes of Mg are preferentially removed in fluid during partial weathering, leaving a heavy δ26Mg residuum [4]. Thus, riverine fluxes to the ocean result in a marine reservoir with a δ26Mg = -0.82 ± 0.01 [5], significantly lighter than that of fresh mantle material and its derivatives [1]. Abyssal peridotites recovered from Ocean Drilling Program Leg 209 display a wide range of bulk-rock compositions and have been demonstrated to have interacted with a number of low and high temperature fluids [6]. Peridotite from Hole 1274a has been variably serpentinized at low (c. 200 oC) temperatures. Serpentinized samples from Hole 1268a, have also interacted with a higher temperature fluid (c. 350 oC) with a low Mg/Si ratio resulting in abundant talc formation [6]. Serpentinites contain high concentrations of Mg and are abundantly exposed at the seafloor at slow and ultra-slow oceanic ridges [7,8]. Because peridotites are thought to be a source of Mg to seawater [9] any fractionation of Mg isotopes that accompanies serpentinization will have implications for the composition of Mg in seawater. The δ26Mg of samples from 1274a are similar to primary upper crustal rocks, (UCC δ26Mg = -0.22 ± 0.04 [2]). However, samples from 1268a have fractionated δ26Mg values that are generally enriched in isotopically heavy Mg relative to the UCC, ranging from -0.25 to -0.02‰. These results suggest that serpentinization itself does not cause fractionation of Mg, but that later formation of talc is associated with the preferential retention of isotopically heavy Mg, consistent with secondary silicates formed during continental weathering [e.g. 3]. Mass balance requires that the talc-altered serpentinite must be complimented by an isotopically light component. It seems most likely that this isotopically light Mg will be transferred and mixed into ambient temperature seawater. The impact of this transfer will be dependent on the size of the Mg exchange between peridotite and seawater and the fractionation factor associated with talc alteration. Our data suggest that this would input Mg into seawater that is isotopically light relative to the altered peridotite. [1] Pogge von Strandmann et al., (2011) GCA 75, 5247-5268. [2] Li et al. (2010) GCA 74, 6867-6884. [3] Tipper et al., (2006) EPSL 247, 267-279. [4] Wimpenny et al., (2010) GCA 74, 5259-5279. [5] Foster et al., (2010) Geochem. Geophys. Geosys. 11, doi:10.1029/2010GC003201. [6] Bach et al., (2004) Geochem. Geophys. Geosys. 5, doi:10.1029/2004GC000744. [7] Cannat et al., (1997) Tectonophys. 279, 193-213. [8] Jokat et al., (2003) Nature 423, 962-965. [9] Snow & Dick (1995) GCA, 59, 4219-4235.

Investigation of Cyclodextrin-Enhanced Electrokinetic Soil Remediation. Fate and Transport of Nitroaromatic Contaminants and Cyclodextrin Amendments in Expansive Clays

DTIC Science & Technology

2004-09-01

report increasing adsorption capacity depending on the specific clay type, in the order kaolinite < illite < montmorillonite (11). This finding suggests... kaolinite , illite, and montmorillonite . Finally, there is a wide varia- tion in adsorption constants among the different nitroaromatic compounds...common to micas, chlorites, pyrophyllite, talc, kaolinite , and gibbsite . As is now known, clays typically consist of layered crystalline structures

Ocular manifestations of injection drug use.

PubMed

Kim, Rubin W; Juzych, Mark S; Eliott, Dean

2002-09-01

Injection drug use can result in a variety of severe ocular conditions. Hematogenous dissemination of various fungi and bacteria may produce endophthalmitis with resultant severe visual loss. Retinal arterial occlusive disease may result from talc and other particulate emboli. Most commonly, life-threatening systemic diseases such as endocarditis and HIV infection secondarily affect the eye. Because many of these conditions may result in blindness if untreated, accurate diagnosis and prompt initiation of therapy are essential.

Installation Restoration Program. Phase 2. Confirmation/Quantification. Stage 1. Air Force Plant 4, Fort Worth, Texas. Volume 9. Appendices F-K.

DTIC Science & Technology

1987-12-01

mineralogy and igneous petrology . Consultant to Shield Energy. Inc.; performed mudlogging and well site geology duties on 4,670’ wildcat weil in...Taylor County, Texas. Evaluated prospects for hydrocarbon potential. Prepared geologic reports for drilling prospectus. Geologist, Wold Minerals...Exploration Company; conducted geologic and geophysi- cal mapping in Precambrian metamorphic terrain of West Texas for talc depos- its. Supervised the drilling

Batch compositions for cordierite ceramics

DOEpatents

Hickman, David L.

1994-07-26

Ceramic products consisting principally of cordierite and a method for making them are provided, the method employing batches comprising a mineral component and a chemical component, the mineral component comprising clay and talc and the chemical component consisting essentially of a combination of the powdered oxides, hydroxides, or hydrous oxides of magnesium, aluminum and silicon. Ceramics made by extrusion and firing of the batches can exhibit low porosity, high strength and low thermal expansion coefficients.

Slab dehydration recorded in subducted serpentine sea-mount

NASA Astrophysics Data System (ADS)

Okamoto, K.; Fukumura, S.; Ishimori, C.; Jung, H.

2014-12-01

It has been considered that there is a correlation between the double seismic zones and metamorphic dehydration reaction in deep slab. The lower seismic plane of the double seismic zone is considered to be located on the 600 oC isotherm in the subducting lithosphere. Antigorite terminal reaction is highly temperature sensitive around 600 oC. Therefore it has been proposed that the oceanic lithosphere was hydrated forming serpentine prior to subduction, then serpentine was decomposed to release fluid causing dehydration embrittlement in the slab. In order to unravel relation between dehydration and seismic deformation, we have investigated dehydration process of natural metamorphic rocks recording very cold geothermal history in the crust and lithosphere in the slab. Metamorphic olivine after antigorite has been described in Italian Alps and also from the Mt. Shiraga, Japan [1]. However, the olivine was formed with talc and fluid by antigorite breakdown reaction in pressures lower than 1.5 GPa. Spinifex olivine with opx in the Cerro del Almirez [2], is the product at pressures (P > 1.5 GPa) relevant to the lower seismic plane beneath Northeast Japan. It clearly indicates the presence of large amount of water facilitate crystallization of elongated olivine with opx. It is also supported by LPO pattern of olivines determined by EBSD. Fine-grained olivine-rich samples shows that Type-C fabric pattern is dominant, suggesting deformation under water-rich condition [3]. With metamorphic olivines, chlorite was also recrystallized, suggesting that water would be transported farther down to deep. The estimated dehydration reaction has a negative P-T slope at pressures higher than 1.5 GPa. The reaction is volume reducing reaction and the olivine-opx spinifex texture was formed under volume reducing reaction. In the warm slab beneath SW Japan, the reaction has a positive slope in P-T space and forms olivine+talc+fluid. From microstrucral and petrological analysis of the Serpentinite in the Sambagawa high P/T metamorphic rocks, we found that the olivine with talc, is preserved mainly in the vein along the shear crack in mylonitized serpentinite. References: [1] K. Okamoto et al., Geochemistry, 46 205-215 (2013). [2] V. Trommsdorff et al., CMP, 132, 139-148 (1998). [3] Jung H, Karato S., Science 293, 1460-1463 (2001)

Metasomatism-induced magnesium isotope fractionation in ultramafic rocks: Evidence from the Franciscan Complex, California

NASA Astrophysics Data System (ADS)

Li, W. Y.; Teng, F. Z.; Xiao, Y.

2016-12-01

To investigate the behaviour of Mg isotopes during metasomatic reactions between peridotites and infiltrating fluids along the slab-mantle interface, we analyzed Mg isotopic compositions of a set of well-characterized samples from the ultramafic blocks in the Franciscan Complex of California [1]. The Group 1 and Group 2 samples that were defined by the initial serpentinization and complete serpentinization of peridotites at temperatures of 450-500 ºC, respectively [1], have δ26Mg values (from -0.26 to -0.14‰) clustered around the mantle value. This suggests that Mg isotope fractionation during serpentinization by slab-derived fluids, if any, is small. By contrast, the Group 3 samples that were defined by the replacement of serpentine by talc [1], are enriched in heavy Mg isotopes (δ26Mg of -0.13 to -0.01‰). This may reflect the loss of light Mg isotopes into fluids during the dehydration reaction that produced talc from serpentine, which is consistent with previous observations that secondary clay minerals preferentially incorporate heavy Mg isotopes during water-rock interactions [2, 3]. The Group 4 samples that were defined by the further replacement of talc by tremolite [1], however, have light Mg isotopic compositions (δ26Mg of -0.50 to -0.41‰). Such a shift towards light Mg isotopic compositions likely results from metasomatism by fluids that derived from isotopically light carbonates, which is supported by the remarkably higher CaO content of Group 4 samples (from 6.9 to 9.2 wt%) than Group 3 ones (from 1.1 to 1.4 wt%). Collectively, significant Mg isotopic variations occur during metasomatism of peridotites in the mantle wedge, which would potentially lead to heterogeneous Mg isotopic compositions in arc lavas [4]. Therefore, Mg isotopes can be used as a powerful tracer of crust-mantle interaction at subduction zones. [1] King et al. (2003) Geol. Soc. Am. Bull. 115, 1097-1109. [2] Teng et al. (2010) Earth Planet. Sci. Lett. 300, 63-71. [3] Wimpenny et al. (2014) Geochim. Cosmochim. Acta 128, 178-194. [4] Teng et al. (2016) Proc. Natl. Acad. Sci. 113, 7082-7087. et al. (2016) Proc. Natl. Acad. Sci. 113, 7082-7087.

Hydration of the Atlantis Massif: Halogen, Noble Gas and In-Situ δ18O Constraints

NASA Astrophysics Data System (ADS)

Williams, M. J.; Kendrick, M. A.; Rubatto, D.

2017-12-01

A combination of halogen (Cl, Br, I), noble gases (He, Ne, Ar, Kr and Xe) and in situ oxygen isotope analysis have been utilized to investigate the fluid-mobile element record of hydration and alteration processes at the Atlantis Massif (30°N on the Mid-Atlantic Ridge). The sample suite investigated includes serpentinite, talc-amphibole ± chlorite schist and hydrated gabbro recovered by seafloor drilling undertaken at sites on a transect across the Atlantis Massif during IODP Expedition 357. Serpentine mesh and veins analysed in-situ by SHRIMP SI exhibit δ18O from 6‰ down to ≈0‰, suggesting serpentinization temperatures of 150 to >280°C and water/rock ratios >5. Differences of 1.5-2.5‰ are observed between adjacent generations of serpentine, but the δ18O range is similar at each investigated drilling site. Halogen and noble gas abundances in serpentinites, talc-amphibole schist and hydrated gabbro have been measured by noble gas mass spectrometry of both irradiated and non-irradiated samples. Serpentinites contain low abundances of halogens and noble gases (e.g. 70-430 ppm Cl, 4.7-12.2 x 10-14 mol/g 36Ar) relative to other seafloor serpentinites. The samples have systematically different Br/Cl and I/Cl ratios related to their mineralogy. Serpentinites retain mantle-like Br/Cl with a wide variation in I/Cl that stretches toward seawater values. Talc-amphibole schists exhibit depletion of Br and I relative to Cl with increasing Cl abundances, suggesting tremolite exerts strong control on halogen abundance ratios. Serpentinites show no evidence of interaction with halogen-rich sedimentary pore fluids. Iodine abundances are variable across serpentinites, and are decoupled from Br and Cl; iodine enrichment (up to 530 ppb) is observed within relatively oxidised and clay-bearing samples. Serpentinized harzburgites exhibit distinct depletion of Kr and Xe relative to atmospheric 36Ar in seawater. Oxygen isotope compositions and low abundances of both halogens and noble gases are consistent with high water/rock ratios. Successive generations of serpentine have δ18O trends suggesting exposure to higher W/R ratios during exhumation and deformation of the massif. Low noble gas abundances of may also be influenced by thermal loss related to impregnation and intrusion of the Massif by gabbros and dolerites.

Fiscal Year 1988 Technical Objective Document.

DTIC Science & Technology

1987-03-01

CELLS BATTERIES PHO0TO VOL TAlC S HIGH EFFICIENCY CELLS ____: ___ HARDENING ( SCOPA, 6.3 I It LIGHTWEIGHT ARRAYS _ [ NUCLEAR I THERMAL ...QUALIFIED 0 35 WH / LB, 150 W /LB, LOW EARTH ORBIT CELLS o HIGH EFFICIENCY PHOTOVOLTAICS ( 11 - 18 % TO 30% O HARDENED ARRAY ( SMATH II) -" 0 LIGHTWEIGHT...PHOTOVOLTAICS HIGH EFFICIENCY SOLAR CELLS HIG SOLARCIE LLS ( SURVIVABLE CONCENTRATORS A; IELN D IN 1K1 Ga’s SCOPA 6 3 I .6 . 6 - E.,J-E I

Neurological Limitations of Aircraft Operations: Human Performance Implications (les Limitations neurologiques des operations aeriennes: les Consequences pour les performances des equipages).

DTIC Science & Technology

1996-04-01

Amniotic fluid Debris?* Young women Long bone fracture Fat * Any age Chronic intravenous drug users Talc* Any age Disseminated intravascular coagulapathy...maximal stress at which bone fracture occurs. This study demonstrated the usefulness of finite Results from centrifuge experiments element analysis for...Vine Street M/S 455 Philadelphia, PA 19102-1192, USA SUMMARY Exposure to Impact Acceleration (15). In these reports, fracture of the bones, dislocation

Antibacterial effects of minerals from ores indigenous to Korea.

PubMed

Park, Seul Ki; Lee, Chang Won; Lee, Mi Young

2009-01-01

We tested the antibacterial properties of a mix of minerals consisting mainly of sericite, talc, and halloysite from Korea. The preparation showed clear growth inhibition of the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the gram-positive bacteria Staphylococcus aureus subsp. aureus, S. epidermidis, and Bacillus cereus, as well as the anaerobic bacterium Propionibacterium acnes. These results indicate that this preparation, made from ore minerals indigenous to Korea, could be used to develop new antibacterial reagents.

Mechanical properties of micro-injected HDPE composites

NASA Astrophysics Data System (ADS)

Bongiorno, A.; Pagano, C.; Agnelli, S.; Baldi, F.; Fassi, I.

2016-03-01

Micro-injection moulding is one of the key manufacturing technologies for the mass production of high value polymeric miniaturized-components. However, this process is not just a straightforward down scaling of the conventional injection moulding technique. Indeed, during the micro-injection the polymer melt is forced to flow at high strain rates through very small channels in non-isothermal conditions, and this can lead to complex microstructures and to parts with unexpected performances. In this work, the relationships among the processing conditions, the mechanical properties and the microstructural characteristics of miniaturized specimens obtained by injection moulding were investigated. Two model systems were considered with the same filler content of 15% wt. (HDPE-talc and HDPE-glass beads), representative of two different types of micro-composites: containing lamellar and spherical micro-particles, respectively. The attention was focused on the influence of the filler type and the process conditions on the mechanical behaviour, examined by uniaxial tensile tests and dynamic-mechanical analyses, and on the morphological characteristics of the specimens, examined by microscopy analyses. The results highlight that mechanical response of the miniaturized specimens is significantly affected by both the filler and the process conditions that can have an influence on the polymer microstructure. Lamellar composites showed the best performance due to the orientation of the talc particles during the micro-injection process, while, different morphologies of the skin/core transition region in dependence on the process temperatures were observable.

Climbing Ability of the Common Bed Bug (Hemiptera: Cimicidae).

PubMed

Hottel, B A; Pereira, R M; Gezan, S A; Qing, R; Sigmund, W M; Koehler, P G

2015-05-01

Little is known about what factors influence the climbing ability of bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), in relation to the various surfaces they encounter. We examined how sex, time since last fed, and what surfaces the bed bugs were in contact with affected their climbing performance. The effects of sex and time since fed were tested by counting the number of bed bugs able to climb a 45° slope. The pulling force was recorded using an analytical balance technique that captured the sequential vertical pulling force output of bed bugs attached to various surfaces. Recently fed female bed bugs were found to have the most difficulty in climbing smooth surfaces in comparison with males. This difference can be explained by the larger weight gained from bloodmeals by female bed bugs. A variety of vertical pulling forces were observed on surfaces ranging from sandpaper to talc powder-covered glass. For surfaces not treated with talc powder, bed bugs generated the least amount of vertical pulling force from synthetically created 0.6-µm plastron surfaces. This vast range in the ability of bed bugs to grip onto various surfaces may have implications on limiting bed bugs dispersal and hitchhiking behaviors. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ultramafic rocks of the western Idaho suture zone: Asbestos Peak and Misery Ridge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Godchaux, M.M.; Bonnichsen, B.

1993-04-01

The Western Idaho Ultramafic Belt extends northward from the town of Weiser to the northern end of Dworshak Reservoir; in its northern portion most of the ultramafic bodies are localized along the suture zone where the Mesozoic oceanic accreted terranes meet the continental craton. Of the twenty bodies investigated, all are small, all are in fault contact with their metavolcanic and metasedimentary host rocks, all have been metamorphosed, and all display deformational fabrics in at least some portion of the outcrop area, suggesting that deformation continued after peak metamorphism. The degree of metamorphism ranges from incipient serpentinization to attainment ofmore » equilibrium in the upper amphibolite facies. Some bodies have been intruded by granitic dikes or pegmatite veins after emplacement, and have locally undergone contact metasomatism. Two particularly complex bodies, Asbestos Peak and Misery Ridge, were chosen for detailed petrographic and chemical study. Asbestos Peak is composed mostly of decussate anthophyllite-talc rock containing isolated patches of harzburgite protolith, and has blackwall border zones. Misery Ridge is composed mostly of coarse-grained sheared tremolite-talc schist without remnant protolith, and lacks true blackwall zones. Both bodies exhibit an unusual and enigmatic hornblende-poikiloblastic garnet-green spinel-skeletal ilmenite assemblage, present in some places as well-defined border zones and in other places as cross-cutting bodies.« less

Solventless dry powder coating for sustained drug release using mechanochemical treatment based on the tri-component system of acetaminophen, carnauba wax and glidant.

PubMed

Hoashi, Yohei; Tozuka, Yuichi; Takeuchi, Hirofumi

2013-02-01

Solventless dry powder coating methods have many advantages compared to solvent-based methods: they are more economical, simpler, safer, more environmentally friendly and easier to scale up. The purpose of this study was to investigate a highly effective dry powder coating method using the mechanofusion system, a mechanochemical treatment equipped with high compressive and shearing force. Acetaminophen (AAP) and carnauba wax (CW) were selected as core particles of the model drug and coating material, respectively. Mixtures of AAP and CW with and without talc were processed using the mechanofusion system. Sustained AAP release was observed by selecting appropriate processing conditions for the rotation speed and the slit size. The dissolution rate of AAP processed with CW substantially decreased with an increase in talc content up to 40% of the amount of CW loaded. Increasing the coating amount by two-step addition of CW led to more effective coating and extended drug release. Scanning electron micrographs indicated that CW adhered and showed satisfactory coverage of the surface of AAP particles. Effective CW coating onto the AAP surface was successfully achieved by strictly controlling the processing conditions and the composition of core particles, coating material and glidant. Our mechanochemical dry powder coating method using the mechanofusion system is a simple and promising means of solventless pharmaceutical coating.

Improving the de-agglomeration and dissolution of a poorly water soluble drug by decreasing the agglomerate strength of the cohesive powder.

PubMed

Allahham, Ayman; Stewart, Peter J; Das, Shyamal C

2013-11-30

Influence of ternary, poorly water-soluble components on the agglomerate strength of cohesive indomethacin mixtures during dissolution was studied to explore the relationship between agglomerate strength and extent of de-agglomeration and dissolution of indomethacin (Ind). Dissolution profiles of Ind from 20% Ind-lactose binary mixtures, and ternary mixtures containing additional dibasic calcium phosphate (1% or 10%; DCP), calcium sulphate (10%) and talc (10%) were determined. Agglomerate strength distributions were estimated by Monte Carlo simulation of particle size, work of cohesion and packing fraction distributions. The agglomerate strength of Ind decreased from 1.19 MPa for the binary Ind mixture to 0.84 MPa for 1DCP:20Ind mixture and to 0.42 MPa for 1DCP:2Ind mixture. Both extent of de-agglomeration, demonstrated by the concentration of the dispersed indomethacin distribution, and extent of dispersion, demonstrated by the particle size of the dispersed indomethacin, were in descending order of 1DCP:2Ind>1DCP:20Ind>binary Ind. The addition of calcium sulphate dihydrate and talc also reduced the agglomerate strength and improved de-agglomeration and dispersion of indomethacin. While not definitively causal, the improved de-agglomeration and dispersion of a poorly water soluble drug by poorly water soluble components was related to the agglomerate strength of the cohesive matrix during dissolution. Copyright © 2013 Elsevier B.V. All rights reserved.

Safety and Complications of Medical Thoracoscopy

PubMed Central

Nour Moursi Ahmed, Shimaa; Mohammadien, Hamdy Ali; Tanikawa, Yoshimasa; Tsuboi, Rie; Sugiyama, Keiji

2016-01-01

Objectives. To highlight the possible complications of medical thoracoscopy (MT) and how to avoid them. Methods. A retrospective and prospective analysis of 127 patients undergoing MT in Nagoya Medical Center (NMC) and Toyota Kosei Hospital. The data about complications was obtained from the patients, notes on the computer system, and radiographs. Results. The median age was 71.0 (range, 33.0–92.0) years and 101 (79.5%) were males. The median time with chest drain after procedure was 7.0 (range, 0.0–47.0) days and cases with talc poudrage were 30 (23.6%). Malignant histology was reported in 69 (54.3%), including primary lung cancer in 35 (27.5), mesothelioma in 18 (14.2), and metastasis in 16 (12.6). 58 (45.7%) revealed benign pleural diseases and TB was diagnosed in 15 (11.8%). 21 (16.5%) patients suffered from complications including lung laceration in 3 (2.4%), fever in 5 (3.9%) (due to hospital acquired infection (HAI) in 2, talc poudrage in 2, and malignancy in 1), HAI in 2 (1.6%), prolonged air-leak in 14 (11.0%), and subcutaneous emphysema in 1 (0.8%). Conclusions. MT is generally a safe procedure. Lung laceration is the most serious complication and should be managed well. HAI is of low risk and can be controlled by medical treatment. PMID:27413774

Thermochemistry of dense hydrous magnesium silicates

NASA Technical Reports Server (NTRS)

Bose, Kunal; Burnley, Pamela; Navrotsky, Alexandra

1994-01-01

Recent experimental investigations under mantle conditions have identified a suite of dense hydrous magnesium silicate (DHMS) phases that could be conduits to transport water to at least the 660 km discontinuity via mature, relatively cold, subducting slabs. Water released from successive dehydration of these phases during subduction could be responsible for deep focus earthquakes, mantle metasomatism and a host of other physico-chemical processes central to our understanding of the earth's deep interior. In order to construct a thermodynamic data base that can delineate and predict the stability ranges for DHMS phases, reliable thermochemical and thermophysical data are required. One of the major obstacles in calorimetric studies of phases synthesized under high pressure conditions has been limitation due to the small (less than 5 mg) sample mass. Our refinement of calorimeter techniques now allow precise determination of enthalpies of solution of less than 5 mg samples of hydrous magnesium silicates. For example, high temperature solution calorimetry of natural talc (Mg(0.99) Fe(0.01)Si4O10(OH)2), periclase (MgO) and quartz (SiO2) yield enthalpies of drop solution at 1044 K to be 592.2 (2.2), 52.01 (0.12) and 45.76 (0.4) kJ/mol respectively. The corresponding enthalpy of formation from oxides at 298 K for talc is minus 5908.2 kJ/mol agreeing within 0.1 percent to literature values.

Pleurodesis Using Mistletoe Extract Delivered via a Spray Catheter during Semirigid Pleuroscopy for Managing Symptomatic Malignant Pleural Effusion.

PubMed

Eom, Jung Seop; Ahn, Hyo Yeong; Mok, Jeong Ha; Lee, Geewon; Jo, Eun-Jung; Kim, Mi-Hyun; Lee, Kwangha; Kim, Ki Uk; Park, Hye-Kyung; Lee, Min Ki

Talc poudrage during thoracoscopy is considered the standard procedure for patients with symptomatic malignant pleural effusion (MPE). Until now, no alternative technique other than talc poudrage for pleurodesis during medical thoracoscopy has been proposed. Liquid sclerosants, such as mistletoe extract, have been sprayed evenly into the pleural cavity during semirigid pleuroscopy for chemical pleurodesis. We conducted a retrospective study using the database of semirigid pleuroscopy to identify the usefulness of pleurodesis using a mistletoe extract delivered via a spray catheter during semirigid pleuroscopy for symptomatic MPE. All consecutive patients with symptomatic MPE who underwent semirigid pleuroscopy from October 2015 to September 2016 were registered. The responses were evaluated using chest X- ray or computed tomography 4 weeks after pleurodesis. The study included 43 patients who underwent pleurodesis with mistletoe extract via a spray catheter during semirigid pleuroscopy. Complete and partial responses were seen in 21 (49%) and 19 (44%) patients, respectively. The median duration of chest tube placement after pleurod-esis was 7 days (range 6-8 days) in the 40 patients with complete or partial responses. No cases of severe hemorrhage, empyema formation, respiratory failure, or procedure-related mortality were observed in the subjects at 4 weeks after semirigid pleuroscopy. Pleurodesis with mistletoe extract delivered via a spray catheter during semirigid pleuroscopy is a safe and effective procedure for managing symptomatic MPE. © 2017 S. Karger AG, Basel.

[Increased resistance in mice to Listeria monocytogenes after treatment with a fraction from an inflammatory granuloma].

PubMed

Fauve, R M; Hevin, B

1977-12-19

The multiplication of Listeria monocytogenes in the spleen was decreased between the 3rd and the 11th day following the inflammatory reaction induced in Mice by subcutaneous implantation of talc embedded in a calcium phosphate gel into the dorsal area. A similar activity was observed after injection of SO4 (NH4)2 fractionated extracts from granuloma. The major activities were found in the 33% saturation precipitate and in the 80% saturation supernatant.

Impact of anti-tacking agents on properties of gas-entrapped membrane and effervescent floating tablets.

PubMed

Kriangkrai, Worawut; Puttipipatkhachorn, Satit; Sriamornsak, Pornsak; Pongjanyakul, Thaned; Sungthongjeen, Srisagul

2014-12-01

Tackiness caused by the gas-entrapped membrane (Eudragit(®)RL 30D) was usually observed during storage of the effervescent floating tablets, leading to failure in floatation and sustained release. In this work, common anti-tacking agents (glyceryl monostearate (GMS) and talc) were used to solve this tackiness problem. The impact of anti-tacking agent on the properties of free films and corresponding floating tablets was investigated. GMS was more effective than talc in reducing tackiness of the film. Addition and increasing amount of anti-tacking agents lowered the film mechanical strength, but the coating films were still strong and flexible enough to resist the generated gas pressure inside the floating tablet. Wettability and water vapor permeability of the film decreased with increasing level of anti-tacking agents as a result of their hydrophobicity. No interaction between anti-tacking agents and polymer was observed as confirmed by Fourier transform infrared spectroscopy, powder X-ray diffractometry, and differential scanning calorimetry studies. Increasing amount of anti-tacking agents decreased time to float and tended to retard drug release of the floating tablets. Floating properties and drug release were also influenced by type of anti-tacking agents. The obtained floating tablets still possessed good floating properties and controlled drug release even though anti-tacking agent had some effects. The results demonstrated that the tackiness problem of the floating tablets could be solved by incorporating anti-tacking agent into the gas-entrapped membrane.

Carbonation of Peridotite by CO2-rich Fluids: Insights from Listvenites in the Advocate Ophiolite (Newfoundland)

NASA Astrophysics Data System (ADS)

Menzel, Manuel; Garrido, Carlos J.; Marchesi, Claudio; López Sánchez Vizcaíno, Vicente; Hidas, Károly; Escayola, Monica P.; Jamtveit, Bjørn

2017-04-01

Listvenites are the result of a sequence of reactions of CO2-rich hydrothermal fluids with serpentinite that forms magnesite-quartz rocks in the last reaction step. Listvenites are natural analogues for carbon sequestration by mineral carbonation, fixing large quantities of carbon in relatively small, confined zones of intense reactive fluid flux within serpentinite. The association of listvenite (magnesite-quartz), soapstone (talc-magnesite) and carbonated serpentinite in the mantle section of the Advocate ophiolite complex in Newfoundland (Canada) is an ideal natural example to study the carbonation of serpentinites because the reaction progress is recorded by the differently carbonated assemblages. The Advocate listvenites crop out in a 20-30 m wide zone that can be followed for about 1 km, surrounded by serpentinite and harzburgite. Quartz and magnesite veins are widespread in the central listvenite domain. This mobilization of silica into a vein network is reflected in a depletion of silica in the most carbonated lithologies, whereas most other major elements remain unchanged over a wide range of CO2-contents. Notably, there is a sharp decrease in bulk rock Fe3+/Fetotal from 0.65 - 0.8 in lizardite-chrysotile serpentinites to 0.1 - 0.3 in talc-magnesite rocks and listvenites. High Cr and Ni contents and preserved red-brown Cr-spinel in the carbonated lithologies demonstrate the mantle peridotites provenance of the listvenites. The presence of thin veins of Cr-mica (fuchsite) suggests that Cr was mobilized to some degree. Fine dispersed magnetite trails in magnesite trace serpentine pseudomorphs after olivine, indicating that no deformation occurred in some domains during the carbonation, while deformation was concentrated in talc-rich lithologies. The rheological contrasts of serpentinites, soapstones and listvenites and, in consequence, the formation of veins in response to shear- or extensional fractures may result in a re-opening of pathways for the influx of very CO2-rich fluids that are needed for the formation of listvenites. Carbonated mantle rocks like the Advocate listvenites may represent the best accessible natural analogue for carbonation of serpentinites through bend faulting at the outer rise of trenches, since hydrothermal fluids in those systems may become more CO2-rich due to percolation through overlying sediments, thus allowing for localized intense carbonation. Funding: We acknowledge funding from the People programme (Marie Curie Actions - ITN) of the European Union FP7 under REA Grant Agreement n˚ 608001.

Natural Serpentinite Carbonation at Linnajavri, N-Norway (Invited)

NASA Astrophysics Data System (ADS)

Beinlich, A.; Tominaga, M.; Pluemper, O.; Hoevelmann, J.; Tivey, M.; Andrade Lima, E.; Weiss, B. P.; Austrheim, H.; Jamtveit, B.

2013-12-01

Investigation of natural mafic and ultramafic rock carbonation driven by the infiltration of CO2-bearing fluids into a solid rock unit provides insight into feedback mechanisms that may become important for in situ sequestration schemes of anthropogenic CO2. We present observations from massively carbonated serpentinites at Linnajavri, N-Norway, where completely serpentinized fragments of the dismembered ophiolite are hydrothermally altered on a km-scale to ophicarbonate (serpentine + Mg-carbonate), soapstone (talc + Mg-carbonate) and listvenite (quartz + Mg-carbonate). Field observations indicate that tectonic preprocessing of the serpentinite facilitated fluid infiltration. Listvenite is indicative of the most intense carbonation and is present along the tectonic contact of the ophiolite with the underlying carbonate-mica schist. Soapstone/steatite is indicative of less intense carbonation, forms m-wide reaction halos around fractures within the serpentinite and is also present as massive body between the listvenite and unaltered serpentinite. Sharp reaction interfaces between the soapstone and serpentinite can be traced for several hundred meters and are defined by the breakdown of antigorite to form magnesite and talc. The soapstone-listvenite transition zones are not entirely exposed in the field and are less than 5 m wide. 18O thermometry using the isotopic composition of quartz/talc and coexisting magnesite derived from veins and bulk rock samples indicate an isothermal formation of listvenite and soapstone at ~275°C. The corresponding isotopic signature of the fluid (δ13CVPDB = 2.2(5) ‰) derived from the δ13C composition of magnesite suggests an interaction with crustal rocks and devolatilization of associated overthrusted sediments as a possible source for the CO2. He- and Hg-porosimetry data, mass-balance calculations, and the preservation of serpentinite structures imply an isovolumetric alteration, which indicates that the carbonation declined due to the cessation of externally supplied CO2. The presence of sharp alteration fronts implies that reaction rates were fast relative to CO2 transport rates. Carbonation at Linnajavri was accompanied by partial dissolution of (Cr)-magnetite and incorporation of the released Fe in precipitating carbonate minerals. SQUID microscopy mapping of both natural remanence magnetization (NRM) and anhysteretic remanence magnetization (ARM) confirms different bulk intensities for the serpentinite, soapstone and listvenite samples. The alteration dependent distribution of ferromagnetic minerals suggests that magnetic surface mapping may represent a powerful tool to localize the position of reaction fronts between pristine and carbonated rock types and hence the spatial extent of the carbonation progress.

An Intensive Survey of Archaeological Resources in the Proposed Long Branch Reservoir. Volume 2B

DTIC Science & Technology

1977-01-01

GcGb - Gneissic Gabbro Hematite TGn - Talc Gneiss c - chipped ShGb - Schistic Gabbro a - scratched ShD - Schistic Dolerite f - flake FH/SS - Flint...Hill Sandstone g - ground Mss - Micaceous Sandstone fss - Ferruginous Sandstone A - Argillite c - chert Qtz - Quartz FGQtt - Fine-grained Quartzite Qtt...ARTIFACTS - LONG BRANCI RESERVOIR 41 0 Points Contracti~ng-@ taed, square-based points l a 23MC55 4-4 50 25 9 9.6g b 23MCSS 2-1 74 39 9 22.8g c

Fundamental Study on the Ozone Posttreatment of Reverse Osmosis Permeates from Army Wastewaters.

DTIC Science & Technology

1981-03-01

organics in RC per- meates as well as for the intermediates formed during ozonation of RO permeate. / This involved the use of distillation, head space...This involved the use of distillation, head - space, and purge and trap methods for the concentration of volatile organic constituents and of the...Grams Group 1 Soap 6.26 INaC 1 7 *C Urea 0.0917 Kaolin 1.725 Talc 1 .7i3 Sho%er Clearer 9.0( Group 2 Hail Oil 14.18 Hai I Gel 3.36 Shampoo 0.456

DETAIL VIEW OF ARRASTRA, LOOKING SOUTHEAST. THIS OLD TECHNOLOGY IS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL VIEW OF ARRASTRA, LOOKING SOUTHEAST. THIS OLD TECHNOLOGY IS AN ANACHRONISM OF THIS MILL. ORE WAS DUMPED INTO THE STONE LINED TROUGH. AS THE ARRASTRA TURNED LARGE STONES CONNECTED TO THE FOUR ARMS WERE DRAGGED AROUND OVER THE ORE TO CRUSH IT. IT IS CLEAR THAT THIS ARRASTRA WAS POWERED BY MACHINE THOUGH IT IS UNCLEAR EXACTLY HOW IT WAS POWERED. THE WHITE PINE TALC MINE OPENING IS SEEN IN THE DISTANCE AT THE CENTER LEFT EDGE. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

A Novel Approach for Dry Powder Coating of Pellets with Ethylcellulose. Part II: Evaluation of Caffeine Release.

PubMed

Albertini, Beatrice; Melegari, Cecilia; Bertoni, Serena; Dolci, Luisa Stella; Passerini, Nadia

2018-04-01

The objective of this study was to assess the efficacy and the capability of a novel ethylcellulose-based dry-coating system to obtain prolonged and stable release profiles of caffeine-loaded pellets. Lauric and oleic acids at a suitable proportion were used to plasticize ethylcellulose. The effect of coating level, percentage of drug loading, inert core particle size, and composition of the coating formulation including the anti-sticking agent on the drug release profile were fully investigated. A coating level of 15% w/w was the maximum layered amount which could modify the drug release. The best controlled drug release was obtained by atomizing talc (2.5% w/w) together with the solid plasticizer during the dry powder-coating process. SEM pictures revealed a substantial drug re-crystallization on the pellet surface, and the release studies evidenced that caffeine diffused through the plasticized polymer acting as pore former. Therefore, the phenomenon of caffeine migration across the coating layer had a strong influence on the permeability of the coating membrane. Comparing dry powder-coated pellets to aqueous film-coated ones, drug migration happened during storage, though more sustained release profiles were obtained. The developed dry powder-coating process enabled the production of stable caffeine sustained release pellets. Surprisingly, the release properties of the dry-coated pellets were mainly influenced by the way of addition of talc into the dry powder-coating blend and by the drug nature and affinity to the coating components. It would be interesting to study the efficacy of novel coating system using a different API.

Thermal behaviour of procaine and benzocaine Part II: compatibility study with some pharmaceutical excipients used in solid dosage forms

PubMed Central

2013-01-01

Background The compatibility study of active substances with excipients finds an important role in the domain of pharmaceutical research, being known the fact that final formulation is the one administered to the patient. In order to evaluate the compatibility between active substance and excipients, different analytical techniques can be used, based on their accuracy, reproducibility and fastness. Results Compatibility study of two well-known active substances, procaine and benzocaine, with four commonly used excipients, was carried out employing thermal analysis (TG/DTG/HF) and Fourier Transform Infrared Spectroscopy (UATR-FT-IR). The selected excipients were microcrystalline cellulose, lactose monohydrate, magnesium stearate and talc. Equal proportion of active substance and excipients (w/w) was utilized in the interaction study. The absolute value of the difference between the melting point peak of active substances and the one corresponding for the active substances in the analysed mixture, as well the absolute value of the difference between the enthalpy of the pure active ingredient melting peak and that of its melting peak in the different analysed mixtures were chosen as indexes of the drug-excipient interaction degree. All the results obtained through thermal analysis were also sustained by FT-IR spectroscopy. Conclusions The corroboration of data obtained by thermal analysis with the ones from FT-IR spectroscopy indicated that no interaction occurs between procaine and benzocaine, with microcrystalline cellulose and talc, as well for the benzocaine-lactose mixture. Interactions were confirmed between procaine and benzocaine respectively and magnesium stearate, and for procaine and lactose. PMID:23962059

Serpentinization processes: Influence of silica

NASA Astrophysics Data System (ADS)

Huang, R.; Sun, W.; Ding, X.; Song, M.; Zhan, W.

2016-12-01

Serpentinization systems are highly enriched in molecular hydrogen (H2) and hydrocarbons (e.g. methane, ethane and propane). The production of hydrocarbons results from reactions between H2 and oxidized carbon (carbon dioxide and carbon monoxide), which possibly contribute to climate changes during early history of the Earth. However, the influence of silica on the production of H2 and hydrocarbons was poorly constrained. We performed experiments at 311-500 °C and 3.0 kbar using mechanical mixtures of silica and olivine in ratios ranging from 0 to 40%. Molecular hydrogen (H2), methane, ethane and propane were formed, which were analyzed by gas chromatography. It was found that silica largely decreased H2 production. Without any silica, olivine serpentinization produced 94.5 mmol/kg H2 after 20 days of reaction time. By contrast, with the presence of 20% silica, H2 concentrations decreased largely, 8.5 mmol/kg. However, the influence of silica on the production of hydrocarbons is negligible. Moreover, with the addition of 20%-40% silica, the major hydrous minerals are talc, which was quantified according to an established standard curve calibrated by infrared spectroscopy analyses. It shows that silica greatly enhances olivine hydration, especially at 500 °C. Without any addition of silica, reaction extents were <5% at 17 days during olivine serpentinization at 500 °C and 3.0 kbar. By contrast, with the presence of 50% silica, olivine was completely transformed to talc within 9 days. This study indicates that silica impedes the oxidation of ferrous iron into ferric iron, and that rates of olivine hydration in natural geological settings are much faster with silica supply.

Oxygen-isotope exchange and mineral alteration in gabbros of the Lower Layered Series, Kap Edvard Holm Complex, East Greenland

USGS Publications Warehouse

Fehlhaber, Kristen L.; Bird, Dennis K.

1991-01-01

Multiple intrusions of gabbros, mafic dikes, and syenites in the Kap Edvard Holm Complex gave rise to prolonged circulation of meteoric hydrothermal solutions and extreme isotope exchange and mineral alteration in the 3600-m-thick Lower Layered Series gabbros. In the Lower Layered Series, δ18O of plagioclase varies from +0.3‰ to -5.8‰, and it decreases with an increase in the volume of secondary talc, chlorite, and actinolite. In the same gabbros, pyroxenes have a more restricted range in δ18O, from 5.0‰ to 3.8‰ and values of δ18Opyroxene are independent of the abundance of secondary minerals, which ranges from 14% to 30%. These relations indicate that large amounts of water continued to flow through the rocks at temperatures of <500-600°C, altering the gabbros to assemblages of talc + chlorite + actinolite ± epidote ±albite and causing significant oxygen-isotope exchange in plagioclase, but not in pyroxene. The extensive low-temperature secondary mineralization and 18O depletion of plagioclase in the Lower Layered Series are associated with the later emplacement of dikes and gabbros and syenites, which created new fracture systems and provided heat sources for hydrothermal fluid circulation. This produced subsolidus mineral alteration and isotope exchange in the Lower Layered Series that are distinct from those in the Skaergaard and Cuillin gabbros of the North Atlantic Tertiary province, but are similar to those observed in some oceanic gabbros.

Successful closure of chronic BPF by thoracoscopy after failure of endoscopic fibrin glue application and thoracoplasty.

PubMed

Tschopp, J M; Evéquoz, D; Karrer, W; Aymon, E; Naef, A P

1990-03-01

We report a case of chronic debilitating BPF following right upper lobe resection. Despite several endobronchial applications of fibrin glue, we could not close it. Since the patient was extremely debilitated by symptoms due to the BPF, a thoracoplasty was attempted but was not successful. Finally, the BPF was definitely closed by instillation of talc into the pleura through thoracoscopy. To our knowledge, this is the first reported case of chemical closure of a recalcitrant BPF by the route of thoracoscopy. It also shows the failure of endoscopic fibrin glue application in such a condition.

The structure of mononuclear phagocytes differentiating in vivo. III. The effect of particulate foreign substances.

PubMed

Goldner, R D; Adams, D O

1977-11-01

The response of mononuclear phagocytes to three inert particles--barium sulfate, talc, and thorium dioxide--was studied by correlated light and electron microscopy. All three particles induced maturation of the mononuclear phagocytes, which proceeded to the stage of the mature macrophage and required 7 to 9 days. Once established, maturation persisted as long as 45 days, as did the inert particles. The resultant lesions, dense aggregates of mature macrophages, were termed mature granulomas. The resultant maturation differed from that produced by digestible bacteria in tempo and extent but not in pattern.

Production, characterization, and modeling of mineral filled polypropylene filaments

NASA Astrophysics Data System (ADS)

George, Brian Robert

1999-11-01

This research produced mineral filled polypropylene filaments using a variety of fillers, characterized these filaments, and attempted to model their mechanical properties with current composite models. Also, these filaments were compared with bone to determine if they are suitable for modeling the mechanical properties of bone. Fillers used consist of wollastonite, talc, calcium carbonate, titanium dioxide, and hydroxyapatite. Fillers and polypropylene chips were combined and extruded into rods with the use of a mixer. The rods were chipped up and then formed into filaments through melt extrusion utilizing a piston extruder. Filaments with volume fractions of filler of 0.05, 0.10, 0.15, and 0.20 were produced. Additionally, some methods of trying to improve the properties of these filaments were attempted, but did not result in any significant property improvements. The fillers and filaments were visually characterized with a scanning electron microscope. Cross-sections, filament outer surfaces, fracture surfaces, and longitudinal cut open surfaces were viewed in this manner. Those filaments with anisotropic filler had some oriented filler particles, while all filaments suffered from poor adhesion between the polypropylene and the filler as well as agglomerations of filler particles. Twenty specimens of each filament were tensile tested and the average tenacity, strain, and modulus were calculated. Filaments containing talc, talc and wollastonite, titanium dioxide, or hydroxyapatite suffered from a drastic transition from ductile to brittle with the addition of 0.05 volume fraction of filler. This is evidenced by the sharp decrease in strain at this volume fraction of filler when compared to the strain of the unfilled polypropylene filament. Additionally, these same filaments suffered a sharp decrease in tenacity at the same volume fraction. These instant decreases are attributed to the agglomerations of filler in the filament. Generally, the modulus of the filaments increased with the increase in concentration of filler. The tensile tenacity, strain, and modulus were modeled with current composite models for particulate filled composites. The tenacity and strain models did not accurately predict the properties of the filaments, while the modulus models were more accurate, perhaps because the agglomerations of filler did not affect the modulus as much as it affected the tenacity and strain of the filaments. Production, characterization, and modeling of these filaments indicates that there are many areas for improvements, such as improved mixing of the filler and polypropylene, increased adhesion between matrix and filler, and decreased agglomerations of filler. Mechanically, these filaments can not match the properties of bone. However, they do have many structural similarities at the micro-mechanical level, so with some improvements in properties these filaments may be suitable models for modeling bone behavior.

TALC: a new deployable concept for a 20m far-infrared space telescope

NASA Astrophysics Data System (ADS)

Durand, Gilles; Sauvage, Marc; Bonnet, Aymeric; Rodriguez, Louis; Ronayette, Samuel; Chanial, Pierre; Scola, Loris; Révéret, Vincent; Aussel, Hervé; Carty, Michael; Durand, Matthis; Durand, Lancelot; Tremblin, Pascal; Pantin, Eric; Berthe, Michel; Martignac, Jérôme; Motte, Frédérique; Talvard, Michel; Minier, Vincent; Bultel, Pascal

2014-08-01

TALC, Thin Aperture Light Collector is a 20 m space observatory project exploring some unconventional optical solutions (between the single dish and the interferometer) allowing the resolving power of a classical 27 m telescope. With TALC, the principle is to remove the central part of the prime mirror dish, cut the remaining ring into 24 sectors and store them on top of one-another. The aim of this far infrared telescope is to explore the 600 μm to 100 μm region. With this approach we have shown that we can store a ring-telescope of outer diameter 20m and ring thickness of 3m inside the fairing of Ariane 5 or Ariane 6. The general structure is the one of a bicycle wheel, whereas the inner sides of the segments are in compression to each other and play the rule of a rim. The segments are linked to each other using a pantograph scissor system that let the segments extend from a pile of dishes to a parabolic ring keeping high stiffness at all time during the deployment. The inner corners of the segments are linked to a central axis using spokes as in a bicycle wheel. The secondary mirror and the instrument box are built as a solid unit fixed at the extremity of the main axis. The tensegrity analysis of this structure shows a very high stiffness to mass ratio, resulting into 3 Hz Eigen frequency. The segments will consist of two composite skins and honeycomb CFRP structure build by replica process. Solid segments will be compared to deformable segments using the controlled shear of the rear surface. The adjustment of the length of the spikes and the relative position of the side of neighbor segments let control the phasing of the entire primary mirror. The telescope is cooled by natural radiation. It is protected from sun radiation by a large inflatable solar screen, loosely linked to the telescope. The orientation is performed by inertia-wheels. This telescope carries a wide field bolometer camera using cryocooler at 0.3K as one of the main instruments. This telescope may be launched with an Ariane 6 rocket up to 800 km altitude, and use a plasma stage to reach the Lagrange 2 point within 18 month. The plasma propulsion stage is a serial unit also used in commercial telecommunication satellites. When the plasma launch is completed, the solar panels will be used to provide the power for communication, orientation and power the cryo-coolers for the instruments. The guide-line for development of this telescope is to use similar techniques and serial subsystems developed for the satellite industry. This is the only way to design and manufacture a large telescope at a reasonable cost.

Copper Solubility and Speciation in Mineral-Buffered Fluids at Crust to Upper Mantle Conditions

NASA Astrophysics Data System (ADS)

Hack, A. C.; Mavrogenes, J. A.; Berry, A. J.

2003-12-01

Fluid inclusions, synthesised in a piston-cylinder apparatus, were used to trap representative high P-T fluid samples under mineral-buffered conditions in the systems Cu2O-MgO-SiO2-HCl-H2O and Cu-K2O-Al2O3-SiO2-Fe3O4-Fe2O3-HCl-H2O at up to 850° C and 1.7 GPa, and as a function of salinity to 11 mol/kg Cl. Copper solubility and speciation were obtained by analysing individual fluid inclusions by excimer laser ablation inductively coupled mass spectrometry (LA-ICP-MS), proton induced X-ray emission (PIXE) and Cu K-edge X-ray absorption near edge structure (XANES) spectroscopy. Quenched capsule fluids were also analysed. At 710° C copper-cuprite-talc-quartz solubility in aqueous fluid containing 1 mol/kg Cl increases with P to at least 1.7 GPa. Conspicuously, with increasing P (> ˜ 0.5 GPa) talc solubility increases and molal Cu concentrations exceed those of Cl. Isothermal Cu solubility appears to mimic the solubility isopleths in the SiO2-H2O system. Solubility trends suggest that the stability field of copper(I) hydroxide complexes (e.g. Cu(OH)aq) expands to higher salinities such that H2O may become an effective ligand at high-P. At constant P (e.g. 0.35 GPa) solubility decreases with increasing T (i.e. > 525° C). High-T Cu K-edge XANES spectra of single homogenised synthetic fluid inclusions indicate that highly coordinated chlorocopper(I) complexes (e.g. Cu:Cl, 1:3 to 4) predominate at high salinity, whereas lower-order linear Cu-Cl coordination predominates at lower salinities, in fluids buffered by quartz-talc-copper-cuprite. This is consistent with the interpretation of the solubility data. At equivalent salinity, T and P conditions, spectra for fluids buffered by native copper-orthoclase-sillimanite-quartz-magnetite-hematite show no evidence for higher-order chlorocopper(I) complexes. Preliminary extended X-ray absorption fine structure data for these latter inclusions indicate that [CuCl2]- predominates. The stability of higher-order complexes is strongly coupled to HCl concentrations, which at constant P and T is determined by both the specific mineral assemblage and total salinity. This is the first spectroscopic evidence for highly coordinated chlorocopper(I) complexes in supercritical fluids. Furthermore, the speciation dependence on the buffering mineral assemblage has not been recognized previously. Similarly, this is the first experimental confirmation that copper concentrations in mineral-buffered fluids can be extremely high, e.g. ˜ 10 wt%, substantiating inferences based on natural fluid inclusions associated with porphyry copper ore deposits.

Effectiveness of chemical pleurodesis in spontaneous pneumothorax recurrence prevention: a systematic review

PubMed Central

Hallifax, R J; Yousuf, A; Jones, H E; Corcoran, J P; Psallidas, I; Rahman, N M

2017-01-01

Objectives Spontaneous pneumothorax is a common pathology. International guidelines suggest pleurodesis for non-resolving air leak or recurrence prevention at second occurrence. This study comprehensively reviews the existing literature regarding chemical pleurodesis efficacy. Design We systematically reviewed the literature to identify relevant randomised controlled trials (RCTs), case–control studies and case series. We described the findings of these studies and tabulated relative recurrence rates or ORs (in studies with control groups). Meta-analysis was not performed due to substantial clinical heterogeneity. Results Of 560 abstracts identified by our search strategy, 50 were included in our systematic review following screening. Recurrence rates in patients with chest tube drainage only were between 26.1% and 50.1%. Thoracoscopic talc poudrage (four studies (n=249)) provided recurrence rates of between 2.5% and 10.2% with the only RCT suggesting an OR of 0.10 compared with drainage alone. In comparison, talc administration during video-assisted thoracic surgery (VATS) from eight studies (n=2324) recurrence was between 0.0% and 3.2%, but the RCT did not demonstrate a significant difference compared with bleb/bullectomy alone. Minocycline appears similarly effective post-VATS (recurrence rates 0.0–2.9%). Prolonged air leak and recurrence prevention using tetracycline via chest drain (n=726) is likely to provide recurrence rates between 13.0% and 33.3% and autologous blood patch pleurodesis (n=270) between 15.6% and 18.2%. Conclusions Chemical pleurodesis postsurgical treatment or via thoracoscopy appears to be most effective. Evidence for definitive success rates of each agent is limited by the small number of randomised trials or other comparative studies. PMID:27803156

Pre-EDIT: protocol for a randomised feasibility trial of elastance-directed intrapleural catheter or talc pleurodesis (EDIT) in malignant pleural effusion

PubMed Central

Martin, Geoffrey A; Tsim, Selina; Kidd, Andrew C; Foster, John E; McLoone, Philip; Chalmers, Anthony

2018-01-01

Introduction Non-expansile lung (NEL) is a common cause of talc pleurodesis (TP) failure in malignant pleural effusion (MPE), but is often occult prior to drainage. Reliable detection of NEL would allow patients to be allocated between intrapleural catheter (IPC) and TP. High pleural elastance (PEL) has been associated with NEL in observational studies. Pre-EDIT is a randomised feasibility trial of elastance-directed IPC or TP (EDIT) management using a novel, purpose-built digital pleural manometer (Rocket Medical, UK). Methods and analysis Consecutive patients with MPE without prior evidence of NEL or preference for IPC will be randomised 1:1 between EDIT management and standard care (an attempt at TP). The primary objective is to determine whether sufficient numbers of patients (defined as 30 within 12 months (or 15 over 6 months)) can be recruited and randomised to justify a subsequent phase III trial testing the efficacy of EDIT management. Secondary objectives include safety, technical feasibility and validation of study design elements, including the definition of PEL using 4D pleural MRI before and after fluid aspiration. EDIT involves PEL assessment during a large volume pleural fluid aspiration, followed by an attempt at TP or placement of an IPC within 24 hours. Patients will be allocated to IPC if the rolling average PEL sustained over at least 250 mL fluid aspirated (PEL250) is ≥ 14.5 cm H2O/L. Ethics and dissemination Pre-EDIT was approved by the West of Scotland Regional Ethics Committee on 8 March 2017 (Ref: 17/WS/0042). Results will be presented at scientific meetings and published in peer-reviewed journals. Trial registration number NCT03319186; Pre-results. PMID:29862030

Some features associated with organosilane groups grafted by the sol-gel process onto synthetic talc-like phyllosilicate.

PubMed

Sales, José A A; Petrucelli, Giovanni C; Oliveira, Fernando J V E; Airoldi, Claudio

2006-05-01

Two new lamellar inorganic-organic magnesium silicates have been successfully synthesized by using sol-gel based processes under mild temperature conditions. The talc-organosilicates derived using two silylating agents as the silicon source, (i) 3-chloropropyltrimethoxysilane, and (ii) from the attachment of 5-amino-1,3,4-thiadiazole-2-thiol molecule to this precursor agent, yielded PhMg-Cl and PhMg-Tz phyllosilicates. These organoclays were characterized through elemental analyses, infrared spectroscopy, X-ray diffractometry, surface area, thermogravimetry, and carbon and silicon solid state nuclear magnetic resonance spectroscopy. The results confirmed the presence of organic moieties covalently bonded to the inorganic silicon sheet network of the 2:1 class of phyllosilicates, with a density of organic molecules of 6.6+/-0.1 and 2.7+/-0.2 mmol g(-1) anchored on the inorganic layer and with interlayer distances of 1158 and 1628 pm, respectively. The nuclear magnetic resonances results in the solid state are in agreement with the sequence of carbons distributed in the pendant chains of the original silylating agents and the silicon bonded to oxygen atoms or carbon atoms of the inorganic sheets, as expected for the organically functionalized phyllosilicates. The enhanced potential of the new compound PhMg-Tz as a multi property material was explored in adsorbing cations from aqueous solution. The basic sulfur and nitrogen centers attached to the pendant chains inside the lamellar cavity can coordinate mercury, by presenting an isotherm saturated at 0.19 mmol g(-1) of this heavy metal. The functionality of this organoclay-like material expresses its potential for heavy cation removal from an ecosystem.

Floating-pulsatile release multiparticulate system for chronopharmacotherapy: effect of some hydrophobic additives on the buoyancy and release behavior of particles.

PubMed

Maghsoodi, M

2014-01-01

A blend of floating and pulsatile principles of a drug delivery system would have the advantage that a drug can be released in the upper gastrointestinal (GI) tract after a lag period, which is anticipated for chronotherapy. In this study, microballoons were prepared by an emulsion solvent diffusion technique using Eudragit S100, and hydrophobic additive (magnesium stearate, stearic acid or talc) for time- and site-specific drug release of piroxicam. The effect of hydrophobic additives on the production yield of floating microparticles, buoyant ability for 8 h, release of drug in simulated GI fluids (simulated gastric fluid [SGF] and simulated intestinal fluid [SIF]), mean particle size, apparent particle density, encapsulation efficiency of drug and physical state of incorporated drug were studied. Both production yield and buoyancy of the microballoons were affected by additives in the following order: magnesium stearate, stearic acid>free-additive>talc. The observed difference in yield and the buoyancy of the microballoons could be attributed to the hydrophobic character of the additives and the shell rigidity of the obtained microballoons. Incorporation of hydrophobic additives in the microballoons was found to impart the desired release properties to the microballoons by providing a 2-phase release pattern with initial slow release (5-6%) through 8 h in SGF followed by rapid pulse release (>92%) in SIF through 15 min. The microballoons co-formulated with magnesium stearate or stearic acid, combining excellent buoyancy and suitable drug release pattern of piroxicam, could be useful in chronopharmacotherapy in arthritis. © Georg Thieme Verlag KG Stuttgart · New York.

Effectiveness of chemical pleurodesis in spontaneous pneumothorax recurrence prevention: a systematic review.

PubMed

Hallifax, R J; Yousuf, A; Jones, H E; Corcoran, J P; Psallidas, I; Rahman, N M

2017-12-01

Spontaneous pneumothorax is a common pathology. International guidelines suggest pleurodesis for non-resolving air leak or recurrence prevention at second occurrence. This study comprehensively reviews the existing literature regarding chemical pleurodesis efficacy. We systematically reviewed the literature to identify relevant randomised controlled trials (RCTs), case-control studies and case series. We described the findings of these studies and tabulated relative recurrence rates or ORs (in studies with control groups). Meta-analysis was not performed due to substantial clinical heterogeneity. Of 560 abstracts identified by our search strategy, 50 were included in our systematic review following screening. Recurrence rates in patients with chest tube drainage only were between 26.1% and 50.1%. Thoracoscopic talc poudrage (four studies (n=249)) provided recurrence rates of between 2.5% and 10.2% with the only RCT suggesting an OR of 0.10 compared with drainage alone. In comparison, talc administration during video-assisted thoracic surgery (VATS) from eight studies (n=2324) recurrence was between 0.0% and 3.2%, but the RCT did not demonstrate a significant difference compared with bleb/bullectomy alone. Minocycline appears similarly effective post-VATS (recurrence rates 0.0-2.9%). Prolonged air leak and recurrence prevention using tetracycline via chest drain (n=726) is likely to provide recurrence rates between 13.0% and 33.3% and autologous blood patch pleurodesis (n=270) between 15.6% and 18.2%. Chemical pleurodesis postsurgical treatment or via thoracoscopy appears to be most effective. Evidence for definitive success rates of each agent is limited by the small number of randomised trials or other comparative studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Inorganic Water Repellent Coatings for Thermal Protection Insulation on an Aerospace Vehicle

NASA Technical Reports Server (NTRS)

Fuerstenau, D. W.; Huang, P.; Ravikumar, R.

1997-01-01

The objective of this research was two-fold: first, to identify and test inorganic water-repellent materials that would be hydrophobic even after thermal cycling to temperatures above 600 C and, second, to develop a model that would link hydrophobicity of a material to the chemical properties of its constituent atoms. Four different materials were selected for detailed experimental study, namely, boron nitride, talc, molybdenite, and pyrophyllite, all of which have a layered structure made up of ionic/covalent bonds within the layers but with van der Waals bonds between the layers. The materials tested could be considered hydrophobic for a nonporous surface but none of the observed contact angles exceeded the necessary 90 degrees required for water repellency of porous materials. Boron nitride and talc were observed to retain their water-repellency when heated in air to temperatures that did not exceed 800 C, and molybdenite was found to be retain its hydrophobicity when heated to temperatures up to 600 C. For these three materials, oxidation and decomposition were identified to be the main cause for the breakdown of water repellency after repeated thermal cycling. Pyrophyllite shows the maximum promise as a potential water-repellent inorganic material, which, when treated initially at 900 C, retained its shape and remained hydrophobic for two thermal cycles where the maximum retreatment temperature is 900 C. A model was developed for predicting materials that might exhibit hydrophobicity by linking two chemical properties, namely, that the constituent ions of the compound belong to the soft acid-base category and that the fractional ionic character of the bonds be less than about 20 percent.

African Americans and Hispanics Remain at Lower Risk of Ovarian Cancer Than Non-Hispanic Whites after Considering Nongenetic Risk Factors and Oophorectomy Rates.

PubMed

Wu, Anna H; Pearce, Celeste L; Tseng, Chiu-Chen; Pike, Malcolm C

2015-07-01

Risk factors for invasive epithelial ovarian cancer (IEOC) among Hispanics and African Americans are understudied despite notable differences in incidence relative to non-Hispanic whites. We used multivariate logistic regression to examine parity, oral contraceptive use, tubal ligation, endometriosis, family history of ovarian cancer, and talc use and risk of IEOC among Hispanics (308 cases and 380 controls), African Americans (128 cases and 143 controls), and non-Hispanic whites (1,265 cases and 1,868 controls) using four case-control studies we conducted in Los Angeles County. We expressed each of these factors in the form of increasing risk and calculated population attributable risk percentage (PAR%) estimates for the six risk factors separately and jointly in the three groups. The risk associations with these six well-accepted factors were comparable in the three groups. The significant racial/ethnic differences in the prevalence of these factors and differences in their oophorectomy rates explained 31% of the lower incidence in African Americans compared with non-Hispanic whites, but only 13% of the lower incidence in Hispanics. The PAR%s ranged from 27.5% to 31.0% for no tubal ligation, 15.9% to 22.2% for not using oral contraceptives, and 12.2% to 15.1% for using talc in the three groups. All six risk factors are comparably important in the three groups. Differences in the prevalence of these factors and their oophorectomy rates explained approximately one third of the difference in incidence between African Americans and non-Hispanic whites. Devising strategies to lessen the burden of IEOC will be applicable to all three racial/ethnic groups. ©2015 American Association for Cancer Research.

Development of formulations of biological agents for management of root rot of lettuce and cucumber.

PubMed

Amer, G A; Utkhede, R S

2000-09-01

The effect of various carrier formulations of Bacillus subtilis and Pseudomonas putida were tested on germination, growth, and yield of lettuce and cucumber crops in the presence of Pythium aphanidermatum and Fusarium oxysporum f.sp. cucurbitacearum, respectively. Survival of B. subtilis and P. putida in various carriers under refrigeration (about 0 degree C) and at room temperature (about 22 degrees C) was also studied. In all carrier formulations, B. subtilis strain BACT-0 survived up to 45 days. After 45 days of storage at room temperature (about 22 degrees C), populations B. subtilis strain BACT-0 were significantly higher in vermiculite, kaolin, and bacterial broth carriers compared with other carriers. Populations of P. putida were significantly higher in vermiculite, peat moss, wheat bran, and bacterial broth than in other carriers when stored either under refrigeration (about 0 degree C) or at room temperature (about 22 degrees C) for 15 or 45 days. Germination of lettuce seed was not affected in vermiculite, talc, kaolin, and peat moss carriers, but germination was significantly reduced in alginate and bacterial broth carriers of B. subtilis compared to the non-treated control. Germination of cucumber seed was not affected by any of the carriers. Significantly higher fresh lettuce and root weights were observed in vermiculite and kaolin carriers of B. subtilis compared with P. aphanidermatum-inoculated control plants. Lettuce treated with vermiculite, and kaolin carriers of B. subtilis, or non-inoculated control lettuce plants had significantly lower root rot ratings than talc, peat moss, bacterial broth, and P. aphanidermatum-inoculated control plants. Growth and yield of cucumber plants were significantly higher in vermiculite-based carrier of P. putida than the other carriers and Fusarium oxysporum f.sp. cucurbitacearum-inoculated plants.

What's All the Talc About? Air Entrainment in Dilute Pyroclastic Density Currents

NASA Astrophysics Data System (ADS)

Marshall, B. J.; Andrews, B. J.; Fauria, K.

2015-12-01

A quantitative understanding of air entrainment is critical to predicting the behaviors of dilute Pyroclastic Density Currents (PDCs), including runout distance, liftoff, and mass fractionation into co-PDC plumes. We performed experiments in an 8.5x6x2.6 meter tank using 20 micron talc powder over a range of conditions to describe air entrainment as a function of temperature, duration and mass flux. The experiments are reproducible and are scaled with respect to the densimetric and thermal Richardson numbers (Ri and RiT), Froude number, thermal to kinetic energy density ratio (TEb/KE), Stokes number, and Settling number, such that they are dynamically similar to natural dilute PDCs. Experiments are illuminated with a swept laser sheet and imaged at 1000 Hz to create 3D reconstructions of the currents, with ~1-2 cm resolution, at up to 1.5 Hz. An array of 30 high-frequency thermocouples record the precise temperature in the currents at 3 Hz. Bulk entrainment rates are calculated based on measured current volumes, surface areas, temperatures and velocities. Entrainment rates vary from ~0-0.9 and do not show simple variation with TEb/KE, Ri, or RiT. Entrainment does, however, increase with decreasing eruption duration and increasing mass flux. Our results suggest that current heads entrain air more efficiently than current bodies (>0.5 compared to ~0.1). Because shorter duration currents have proportionally larger heads, their bulk entrainment rates are controlled by those heads, whereas longer duration currents are dominated by their bodies. Our experiments demonstrate that air entrainment, which exerts a fundamental control on PDC runout and liftoff, varies spatially and temporally within PDCs.

Oxidative potential (OP) and mineralogy of iron ore particulate matter at the Gol-E-Gohar Mining and Industrial Facility (Iran).

PubMed

Soltani, Naghmeh; Keshavarzi, Behnam; Sorooshian, Armin; Moore, Farid; Dunster, Christina; Dominguez, Ana Oliete; Kelly, Frank J; Dhakal, Prakash; Ahmadi, Mohamad Reza; Asadi, Sina

2017-03-09

Concentrations of total suspended particulate matter, particulate matter with aerodynamic diameter <2.5 μm (PM 2.5 ), particulate matter <10 μm (PM 10 ), and fallout dust were measured at the Iranian Gol-E-Gohar Mining and Industrial Facility. Samples were characterized in terms of mineralogy, morphology, and oxidative potential. Results show that indoor samples exceeded the 24-h PM 2.5 and PM 10 mass concentration limits (35 and 150 µg m -3 , respectively) set by the US National Ambient Air Quality Standards. Calcite, magnetite, tremolite, pyrite, talc, and clay minerals such as kaolinite, vermiculite, and illite are the major phases of the iron ore PM. Accessory minerals are quartz, dolomite, hematite, actinolite, biotite, albite, nimite, laumontite, diopside, and muscovite. The scanning electron microscope structure of fibrous-elongated minerals revealed individual fibers in the range of 1.5 nm to 71.65 µm in length and 0.2 nm to 3.7 µm in diameter. The presence of minerals related to respiratory diseases, such as talc, crystalline silica, and needle-shaped minerals like amphibole asbestos (tremolite and actinolite), strongly suggests the need for detailed health-based studies in the region. The particulate samples show low to medium oxidative potential per unit of mass, in relation to an urban road side control, being more reactive with ascorbate than with glutathione or urate. However, the PM oxidative potential per volume of air is exceptionally high, confirming that the workers are exposed to a considerable oxidative environment. PM released by iron ore mining and processing activities should be considered a potential health risk to the mine workers and nearby employees, and strategies to combat the issue are suggested.

ANDREWS MOUNTAIN, MAZOURKA, AND PAIUTE ROADLESS AREAS, CALIFORNIA.

USGS Publications Warehouse

McKee, Edwin H.; Schmauch, Steven W.

1984-01-01

On the basis of a mineral survey, local areas near and within the Andrews Mountain, Mazourka, and Paiute Roadless Areas, California have probable and substantiated mineral-resource potential. The principal metallic mineral resources in these roadless areas are gold, copper, and silver with lead, zinc, and tungsten, as lesser resources. A zone of probable resource potential for talc, graphite, and marble is identified in the Mazourka Roadless Area. Metallic mineralization occurs mostly in vein deposits in silicic and carbonate metasedimentary rocks peripheral to Mesozoic plutons and locally in granitic rocks as well. There is little promise for the occurrence of fossil fuel resources in the roadless areas.

Serpentinization as a reactive transport process: The brucite silicification reaction

NASA Astrophysics Data System (ADS)

Tutolo, B. M.; Luhmann, A. J.; Tosca, N. J.; Seyfried, W. E., Jr.

2017-12-01

Serpentinization plays a fundamental role in the biogeochemical and tectonic evolution of the Earth and perhaps many other rocky planetary bodies. Yet, geochemical models still fail to produce accurate predictions of the various modes of serpentinization, which limits our ability to predict a variety of related geological phenomena over many spatial and temporal scales. Here, we utilize kinetic and reactive transport experiments to parameterize the brucite silicification reaction and provide fundamental constraints on SiO2 transport during serpentinization. We show that, at temperatures characteristic of the sub-seafloor at the serpentinite-hosted Lost City Hydrothermal Field, the assembly of Si tetrahedra onto MgOH2 (i.e., brucite) surfaces is a rate-limiting elementary reaction in the production of serpentine and/or talc from olivine. Moreover, a kinetic rate law extracted from our laboratory experiments shows that this reaction is exponentially dependent on the activity of aqueous silica (aSiO2(aq)), such that its rate is orders of magnitude slower near-equilibrium than it is far-from-equilibrium. Calculations performed with this rate law demonstrate that both brucite and Si are surprisingly persistent in serpentinizing environments, leading to elevated Si concentrations in fluids that can be transported over comparatively large distances without equilibrating with brucite. Moreover, applying this rate law to an open-system reactive transport experiment indicates that advection, preferential flow pathways, and reactive surface area armoring can diminish the net rate of Si uptake resulting from this reaction even further. Because brucite silicification is a fundamentally rate-limiting elementary reaction for the production of both serpentine and talc from forsterite, our new constraints are applicable across the many environments where serpentinization occurs. The unexpected but highly consequential behavior of this simple reaction emphasizes the need for considering serpentinization and many other hydrothermal processes in a reactive transport framework whereby fluid, solute, and heat transport are intimately coupled to kinetically-controlled reactions.

Millimeter wave and terahertz dielectric properties of biological materials

NASA Astrophysics Data System (ADS)

Khan, Usman Ansar

Broadband dielectric properties of materials can be employed to identify, detect, and characterize materials through their unique spectral signatures. In this study, millimeter wave, submillimeter wave, and terahertz dielectric properties of biological substances inclusive of liquids, solids, and powders were obtained using Dispersive Fourier Transform Spectroscopy (DFTS). Two broadband polarizing interferometers were constructed to test materials from 60 GHz to 1.2 THz. This is an extremely difficult portion of the frequency spectrum to obtain a material's dielectric properties since neither optical nor microwave-based techniques provide accurate data. The dielectric characteristics of liquids such as cyclohexane, chlorobenzene, benzene, ethanol, methanol, 1,4 dioxane, and 10% formalin were obtained using the liquid interferometer. Subsequently the solid interferometer was utilized to determine the dielectric properties of human breast tissues, which are fixed and preserved in 10% formalin. This joint collaboration with the Tufts New England Medical Center demonstrated a significant difference between the dielectric response of tumorous and non-tumorous breast tissues across the spectrum. Powders such as anthrax, flour, talc, corn starch, dry milk, and baking soda have been involved in a number of security threats and false alarms around the globe in the last decade. To be able to differentiate hoax attacks and serious security threats, the dielectric properties of common household powders were also examined using the solid interferometer to identify the powders' unique resonance peaks. A new sample preparation kit was designed to test the powder specimens. It was anticipated that millimeter wave and terahertz dielectric characterization will enable one to clearly distinguish one powder from the other; however most of the powders had relatively close dielectric responses and only Talc had a resonance signature recorded at 1.135 THz. Furthermore, due to polarization and birefringence effects, it was determined that one can not utilize the dielectric properties of powder-containing packages to differentiate hoax attacks and serious security threats.

Importance of weak minerals on earthquake mechanics

NASA Astrophysics Data System (ADS)

Kaneki, S.; Hirono, T.

2017-12-01

The role of weak minerals such as smectite and talc on earthquake mechanics is one of the important issues, and has been debated for recent several decades. Traditionally weak minerals in fault have been reported to weaken fault strength causing from its low frictional resistance. Furthermore, velocity-strengthening behavior of such weak mineral (talc) is considered to responsible for fault creep (aseismic slip) in the San Andreas fault. In contrast, recent studies reported that large amount of weak smectite in the Japan Trench could facilitate gigantic seismic slip during the 2011 Tohoku-oki earthquake. To investigate the role of weak minerals on rupture propagation process and magnitude of slip, we focus on the frictional properties of carbonaceous materials (CMs), which is the representative weak materials widely distributed in and around the convergent boundaries. Field observation and geochemical analyses revealed that graphitized CMs-layer is distributed along the slip surface of a fossil plate-subduction fault. Laboratory friction experiments demonstrated that pure quartz, bulk mixtures with bituminous coal (1 wt.%), and quartz with layered coal samples exhibited almost similar frictional properties (initial, yield, and dynamic friction). However, mixtures of quartz (99 wt.%) and layered graphite (1 wt.%) showed significantly lower initial and yield friction coefficient (0.31 and 0.50, respectively). Furthermore, the stress ratio S, defined as (yield stress-initial stress)/(initial stress-dynamic stress), increased in layered graphite samples (1.97) compared to quartz samples (0.14). Similar trend was observed in smectite-rich fault gouge. By referring the reported results of dynamic rupture propagation simulation using S ratio of 1.4 (typical value for the Japan Trench) and 2.0 (this study), we confirmed that higher S ratio results in smaller slip distance by approximately 20 %. On the basis of these results, we could conclude that weak minerals have lower initial/yield strength and higher S ratio, and thus restrain magnitude of slip during earthquake.

Deformation associated with the denudation of mantle-derived rocks at the Mid-Atlantic Ridge 13°-15°N: The role of magmatic injections and hydrothermal alteration

NASA Astrophysics Data System (ADS)

Picazo, Suzanne; Cannat, Mathilde; Delacour, AdéLie; EscartíN, Javier; RouméJon, StéPhane; Silantyev, Sergei

2012-09-01

Outcrops of deeply derived ultramafic rocks and gabbros are widespread along slow spreading ridges where they are exposed in the footwall of detachment faults. We report on the microstructural and petrological characteristics of a large number of samples from ultramafic exposures in the walls of the Mid-Atlantic Ridge (MAR) axial valley at three distinct locations at lat. 13°N and 14°45'N. One of these locations corresponds to the footwall beneath a corrugated paleo-fault surface. Bearing in mind that dredging and ROV sampling may not preserve the most fragile lithologies (fault gouges), this study allows us to document a sequence of deformation, and the magmatic and hydrothermal history recorded in the footwall within a few hundred meters of the axial detachment fault. At the three sampled locations, we find that tremolitic amphiboles have localized deformation in the ultramafic rocks prior to the onset of serpentinization. We interpret these tremolites as hydrothermal alteration products after evolved gabbroic rocks intruded into the peridotites. We also document two types of brittle deformation in the ultramafic rocks, which we infer could produce the sustained low magnitude seismicity recorded at ridge axis detachment faults. The first type of brittle deformation affects fresh peridotite and is associated with the injection of the evolved gabbroic melts, and the second type affects serpentinized peridotites and is associated with the injection of Si-rich hydrothermal fluids that promote talc crystallization, leading to strain localization in thin talc shear zones. We also observed chlorite + serpentine shear zones but did not identify samples with serpentine-only shear zones. Although the proportion of magmatic injections in the ultramafic rocks is variable, these characteristics are found at each investigated location and are therefore proposed as fundamental components of the deformation in the footwall of the detachment faults associated with denudation of mantle-derived rocks at the MAR.

High-pressure behaviour of serpentine and elasticity systematics of hydrous and nominally anhydrous phases

NASA Astrophysics Data System (ADS)

Fumagalli, P.; Mookherjee, M.; Stixrude, L. P.

2006-12-01

Serpentine, talc and brucite occur in oceanic crust as alteration products of ultramafic rocks. As mineral phases occurring in the subduction zone setting, both along the slab and within the mantle wedge, they are possible candidates for carrying and tranfer of water to the deep earth. This is manifested by serpentine mud volcanoes, high electrical conductivities, magnetic and seismic anomalies. At high pressure talc transforms to the 10 Å phase. Both the 10 Å phase and serpentine eventually transfer their water content to other dense hydrous magnesium silicates stable at depth greater than 200 km. Most of the mantle's water budget may be contained in nominally anhydrous phases in which hydrogen occurs as non-stoichiometric defects. In order to evaluate the potential for remote detection of mantle water via seismology, we have investigated the elasticity systematics of hydrous phases, supplementing literature data with a new ab initio theoretical study of serpentine. Serpentine shows unusual high-pressure behavior. We predict a symmetry preserving phase transformation involving a proton flip near 25 GPa, and elastic instability at somewhat higher pressures that may be related with experimentally observed amorphization. Results of compression for the low-pressure phase is well represented by a fourth order Birch-Murnaghan finite strain expression with Ko= 81 GPa, Ko'= 9.12 and KoKo"= -142, where K is the bulk modulus, prime indicates pressure derivatives, and O refers to zero pressure. The elastic constant tensor reveals large acoustic anisotropy (41 % in VP) and seismic wave velocities that are significantly higher than those inferred from experiments on serpentinites. We find that serpentine and many other hydrous and nominally anhydrous phases conform closely to generalized Birch's laws in VP, VS, and VB versus density space. Coherent patterns emerge only if hydroxyls are treated as single "atomic" units in the computation of mean atomic weight, suggesting important implications for the understanding of the influence of hydrogen on mineral elasticity.

Molecular dynamics simulation of water at mineral surfaces: Structure, dynamics, energetics and hydrogen bonding

NASA Astrophysics Data System (ADS)

Kalinichev, A. G.; Wang, J.; Kirkpatrick, R.

2006-05-01

Fundamental molecular-level understanding of the properties of aqueous mineral interfaces is of great importance for many geochemical and environmental systems. Interaction between water and mineral surfaces substantially affects the properties of both phases, including the reactivity and functionality of the substrate surface, and the structure, dynamics, and energetics of the near surface aqueous phase. Experimental studies of interfacial water structure and dynamics using surface-sensitive techniques such as sum-frequency vibrational spectroscopy or X-ray and neutron reflectivity are not always possible for many practically important substrates, and their results often require interpretation concerning the atomistic mechanisms responsible for the observed behavior. Molecular computer simulations can provide new insight into the underlying molecular- level relationships between the inorganic substrate structure and composition and the structure, ordering, and dynamics of interfacial water. We have performed a series of molecular dynamics (MD) computer simulations of aqueous interfaces with several silicates (quartz, muscovite, and talc) and hydroxides (brucite, portlandite, gibbsite, Ca/Al and Mg/Al double hydroxides) to quantify the effects of the substrate mineral structure and composition on the structural, transport, and thermodynamic properties of water on these mineral surfaces. Due to the prevalent effects of the development of well-interconnected H-bonding networks across the mineral- water interfaces, all the hydroxide surfaces (including a fully hydroxylated quartz surface) show very similar H2O density profiles perpendicular to the interface. However, the predominant orientations of the interfacial H2O molecules and their detailed 2-dimensional near-surface structure and dynamics parallel to the interface are quite different reflecting the differences in the substrate structural charge distribution and the density and orientations of the surface OH groups. The H2O density profiles and other structural and dynamic characteristics of water at the two siloxane surfaces are very different from each other and from the hydroxide surfaces, since the muscovite surface is negatively charged and hydrophilic, while the talc surface is electrostatically neutral and hydrophobic. In general, at hydrophilic neutral surfaces both donating and accepting H-bonds from the H2O molecules are contributing to the development of the interfacial H-bond network, whereas at hydrophilic but charged surfaces only accepting or donating H-bonds with H2O molecules are possible. At the hydrophobic talc surface H-bonds among H2O molecules dominate the interfacial H-bond network and the water-surface interactions are very weak. The first water layer at all substrates is well ordered parallel to the surface, reflecting substrate crystal structures and indicating the reduced translational and orientational mobility of interfacial H2O molecules. At longer time scale (~100ps) their dynamics can be decomposed into a slow, virtually frozen, regime due to the substrate- bound H2O and a faster regime of almost free water reflecting the dynamics far from the surface. At shorter times (>10ps) the two dynamical regimes are superimposed. The much higher ordering of interfacial water (compared to bulk liquid) can not be adequately described as simply "ice-like". To some extent, it rather resembles the behavior of supercooled water.

Continuous country rock contamination and hydrothermal alteration of the Ni-Cu-PGE sulphide-bearing (ultra-)basic Uitkomst Complex, South Africa

NASA Astrophysics Data System (ADS)

Gauert, Christoph; Globig, Jan

2014-05-01

This mineralized ultrabasic to basic igneous complex of Bushveld Complex age (De Waal et al., 2001) and with affinity to a Bushveld complex primary magma composition Gauert, 1998) deserves further investigation, since new drill core material became available. An intersection of the downdip extension of the complex of constant thickness reveals upper gabbronoritic units which are geochemically evolved and strongly contaminated with quartz by assimilation of country rocks. Hydrothermal, partly deuteric alteration is widespread over the complex, but pronounced in its lower and upper zones. Selective, connate to meteoric fluid ingress, controlled by contact metamorphism (Sarkar et al., 2008) and structure (Joubert, 2013), led to significant deuteric alteration. Highly talc-carbonate altered chromitiferous peridotite sections show formation of cube-shaped spinels, probably indicating auto-metamorphic conditions. Autometamorphism of the ultrabasic rocks produced a wide range of non-sulfide assemblages, despite the relatively restricted compositional range within each rock type; a crucial variable is the XCO2 of the metamorphic fluid. The sulphide mineralogy of the ultramafic-hosted deposit is influenced by the temperature and composition of the hydrothermal fluid. Reduction reactions associated with the serpentinization fronts in the dunitic adcumulates gave rise to Ni-Fe alloy and native Cu bearing assemblages. Greenschist facies hydration gave rise to serpentinites, hosting assemblages rich in pentlandite and in some cases violarite and marcasite, mackinawite, millerite, and valleriite. Oxidized fluids associated with low temperature talc-carbonate alteration in the chromitiferous peridotite formed Ni-sulphide minerals coexisting with pyrite and hematite. Both the sulfide and nickel components in the ore may contain substantial proportions of the total nickel budget. Low temperature alteration effectively redistributed the sulfide elements in serpentinites, leading to highly variable Cu/(Cu+Ni) ratios. In areas of thorough alteration nickel can almost completely reside in sulphide minerals. The country rock contamination in the marginal zones and the alteration appear to continue along the downdip extension with nearly constant intensity over a distance of at least 9 km towards north-west. References: De Waal, S.A., Maier, W., Armstrong, R. and Gauert, C.D.K., 2001. Chemical constraints on the differentiation and emplacement of the Uitkomst Complex, Mpumalanga Province, South Africa, Canadian Mineralogist: 39, 557-571. Gauert, C.D.K., 1998. The Petrogenesis of the Uitkomst Complex, Mpumalanga Province, South Africa. Unpublished Ph.D. thesis, University of Pretoria, 315p. Guenther, C., and Gauert, C., 2013 The spatial distribution and geochemical characteristics of the talc-carbonate alteration of the Uitkomst Complex. 12th biennial SGA meeting, Uppsala, Sweden. Proceedings: 3, 993-996. Joubert, P.L., 2013. Syn- to post-intrusive deformation in the Chromitiferous Harzburgite Unit of the Uitkomst Complex, Nkomati Mine, Mpumalanga Province. Unpublished M.Sc. thesis, University of the Free State, Bloemfontein, South Africa, 155p. Sarkar, A., Ripley, E.M., Li, C., Maier, W.D., 2008. Stable isotope, fluid inclusion, and mineral chemistry constraints on contamination and hydrothermal alteration in the Uitkomst Complex, South Africa. - Chemical Geology, v. 257: 129-138.

Wet powder seal for gas containment

DOEpatents

Stang, Louis G.

1982-01-01

A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

Wet powder seal for gas containment

DOEpatents

Stang, L.G.

1979-08-29

A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

Results of investigations on a 0.0405 scale model ATP version of the NR-SSV orbiter in the North American Aeronautical Laboratory low speed wind tunnel

NASA Technical Reports Server (NTRS)

Mennell, R.; Vaughn, J. E.; Singellton, R.

1973-01-01

Experimental aerodynamic investigations were conducted on a scale model space shuttle vehicle (SSV) orbiter. The purpose of the test was to investigate the longitudinal and lateral-directional aerodynamic characteristics. Emphasis was placed on model component, wing-glove, and wing-body fairing effects, as well as elevon, aileron, and rudder control effectiveness. Angles of attack from - 5 deg to + 30 deg and angles of sideslip from - 5 deg to + 10 deg were tested. Static pressures were recorded on base, fuselage, and wing surfaces. Tufts and talc-kerosene flow visualization techniques were also utilized. The aerodynamic force balance results are presented in plotted and tabular form.

Exsolution in clinoamphiboles

USGS Publications Warehouse

Ross, M.; Papike, J.J.; Weiblen, P.W.

1968-01-01

Ten amphibole specimens from a variety of metamorphic rocks such as talc schists, eclogites, and metamorphosed iron formations contain lamellae of a second amphibole oriented parallel to (101) or (100), or both, of the host. Tremolites, actinolites, and hornblendes commonly have lamellae of a calcium-poor clinoamphibole with P21/m space-group symmetry, or lamellae of citmmingtonite with C2/m space-group symmetry. Likewise ciimmingtonites and P21/m clinoamphiboles commonly contain lamellae of calcium-rich C2/m amphiboles such as tremolite. Results of x-ray diffraction, electron-probe, and microscope studies indicate that most lamellae result from unmixing of a homogeneous amphibole. The P21/m clinoampliibole is analogous to the clinopyroxene pigeonite in agreement with the results of M. G. Bown.

Universal deformation pathways and flexural hardening of nanoscale 2D-material standing folds

NASA Astrophysics Data System (ADS)

Chacham, Helio; Barboza, Ana Paula M.; de Oliveira, Alan B.; de Oliveira, Camilla K.; Batista, Ronaldo J. C.; Neves, Bernardo R. A.

2018-03-01

In the present work, we use atomic force microscopy nanomanipulation of 2D-material standing folds to investigate their mechanical deformation. Using graphene, h-BN and talc nanoscale wrinkles as testbeds, universal force-strain pathways are clearly uncovered and well-accounted for by an analytical model. Such universality further enables the investigation of each fold bending stiffness κ as a function of its characteristic height h 0. We observe a more than tenfold increase of κ as h 0 increases in the 10-100 nm range, with power-law behaviors of κ versus h 0 with exponents larger than unity for the three materials. This implies anomalous scaling of the mechanical responses of nano-objects made from these materials.

Results of investigations on a 0.0405 scale model PRR version of the NR-SSV orbiter in the North American Aeronautical Laboratory low speed wind tunnel

NASA Technical Reports Server (NTRS)

Kingsland, R. B.; Vaughn, J. E.; Singellton, R.

1973-01-01

Experimental aerodynamic investigations were conducted in a low speed wind tunnel on a scale model space shuttle vehicle (SSV) orbiter. The purpose of the test was to investigate the longitudinal and lateral-directional aerodynamic characteristics of the space shuttle orbiter. Emphasis was placed on model component, wing-glove, and wing-body fairing effects, as well as elevon, aileron, and rudder control effectiveness. Angles of attack from - 5 deg to + 30 deg and angles of sideslip of - 5 deg, 0 deg, and + 5 deg were tested. Static pressures were recorded on base, fuselage, and wing surfaces. Tufts and talc-kerosene flow visualization techniques were also utilized. The aerodynamic force balance results are presented in plotted and tabular form.

NIOSH Manual of Analytical Methods (third edition). Fourth supplement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-08-15

The NIOSH Manual of Analytical Methods, 3rd edition, was updated for the following chemicals: allyl-glycidyl-ether, 2-aminopyridine, aspartame, bromine, chlorine, n-butylamine, n-butyl-glycidyl-ether, carbon-dioxide, carbon-monoxide, chlorinated-camphene, chloroacetaldehyde, p-chlorophenol, crotonaldehyde, 1,1-dimethylhydrazine, dinitro-o-cresol, ethyl-acetate, ethyl-formate, ethylenimine, sodium-fluoride, hydrogen-fluoride, cryolite, sodium-hexafluoroaluminate, formic-acid, hexachlorobutadiene, hydrogen-cyanide, hydrogen-sulfide, isopropyl-acetate, isopropyl-ether, isopropyl-glycidyl-ether, lead, lead-oxide, maleic-anhydride, methyl-acetate, methyl-acrylate, methyl-tert-butyl ether, methyl-cellosolve-acetate, methylcyclohexanol, 4,4'-methylenedianiline, monomethylaniline, monomethylhydrazine, nitric-oxide, p-nitroaniline, phenyl-ether, phenyl-ether-biphenyl mixture, phenyl-glycidyl-ether, phenylhydrazine, phosphine, ronnel, sulfuryl-fluoride, talc, tributyl-phosphate, 1,1,2-trichloro-1,2,2-trifluoroethane, trimellitic-anhydride, triorthocresyl-phosphate, triphenyl-phosphate, and vinyl-acetate.

An empirical model for dissolution profile and its application to floating dosage forms.

PubMed

Weiss, Michael; Kriangkrai, Worawut; Sungthongjeen, Srisagul

2014-06-02

A sum of two inverse Gaussian functions is proposed as a highly flexible empirical model for fitting of in vitro dissolution profiles. The model was applied to quantitatively describe theophylline release from effervescent multi-layer coated floating tablets containing different amounts of the anti-tacking agents talc or glyceryl monostearate. Model parameters were estimated by nonlinear regression (mixed-effects modeling). The estimated parameters were used to determine the mean dissolution time, as well as to reconstruct the time course of release rate for each formulation, whereby the fractional release rate can serve as a diagnostic tool for classification of dissolution processes. The approach allows quantification of dissolution behavior and could provide additional insights into the underlying processes. Copyright © 2014 Elsevier B.V. All rights reserved.

The regulation of crystalline silica: an industry perspective.

PubMed

Elzea, J M

1997-01-01

Silica is ubiquitous in the earth's crust. It occurs in trace to large quantities in rocks and soil. Because it is so common, the regulation of silica has affected a large number of industries, including the mining industry and any industry that uses quartz in the manufacture of a products. Mineral commodities that contain silica include diatomite, bentonite, kaolinite, talc, pyrophyllite, sand and gravel, perlite, pumice, dimension stone, and barite. Products that contain minerals, many of which are associated with silica, include paint, paper, rubber, plastic, pharmaceuticals, food, cement, plaster, cat litter, potting soil, plaster board, and miscellaneous construction materials. In collaboration with some agencies and academic centers, the silica industry is supporting research to lower health risks and to improve the methods of detecting this common material.

Effect of Dehydration Reaction on Serpentinite Deformation in Torsion

NASA Astrophysics Data System (ADS)

Vinciguerra, S.; Trovato, C.; Meredith, P. G.; Benson, P. M.; Hirose, T.; Bystricky, M.; Stünitz, H.; Kunze, K.

2003-12-01

Dehydration of serpentine to olivine, talc and water during deformation is critical for understanding the possible localization of deformation into shear zones and the generation of earthquakes along subduction zones. In order to investigate the effect of the dehydration reaction on the strength and ductility of serpentinite, torsion experiments were performed using a Paterson high PT torsion rig at constant shear strain rates of 10-4 to 10-5 s-1, temperatures of 550 to 750 ° C and a confining pressure of 300 MPa, to local shear strains up to γ = 3. We deformed two types of serpentinite: antigorite from Val Malenco, Italy, a high-temperature phase of serpentine (stable at T <500 ° C), and lizardite from Elba, Italy, a low-temperature phase of serpentine (stable at T <400 ° C). Most of the samples were shaped in dog-bone geometry with a central hole along their axial direction which acted as a fluid conduit, enabling an easy escape for any released fluid during the dehydration reaction. We also deformed solid bone-shaped specimens to compare the mechanical behavior of solid and hollow specimens. In both cases, porous alumina spacers were placed on both end sides of specimen and led to the atmosphere through the pore pressure line. Thus our experiments were performed under drained conditions. Antigorite deformed in the semi-brittle field at the run conditions. Visible faults formed probably due to reaction-induced fracturing, and the stress started to drop just after the initial peak stress ( ˜350 MPa at 650 to 700 ° C and ˜280 MPa at 750 ° C). Highly comminuted grains with various sizes along the faults were identified as partially dehydrated antigorite (H2O ˜6 wt%) at 650 ° C and olivine and talc at >700 ° C. Mechanical behavior after the peak stress is thought to occur by cataclastic flow, possibly assisted by diffusion mass transfer processes of these fine-grained reactant minerals. We have also investigated the effect of pre-heating on the strength of antigorite. The peak strength of a sample pre-heated at 750 ° C for 3 hr and then deformed at 700 ° C is 70 MPa lower than a sample deformed directly at 700 ° C. This stress reduction occurred due to the presence of a mechanically weaker reaction product (talc) rather than elevated pore pressure because the sample was deformed under completely drained conditions. By contrast, a solid sample was weaker than hollow ones by ˜100 MPa, mainly due to low permeability of the serpentinite. Excess fluid pressure in solid specimens leads to a drop in the effective pressure and appears to have enhanced the dehydration reaction along micro-fractures. Our data shows that dehydration weakening of serpentinite is caused not as much because of excess pore pressure but more because of the weaker mineral assemblages from the reaction. In contrast to semi-brittle faulting in antigorite, deformation of lizardite at 550 ° C to a bulk shear strain of 0.9 was widely distributed, showing typical ductile microstructures such as boudinage and S-C fabric. A well developed secondary foliation (C-plane) and strong lattice preferred orientations of lizardite grains were observed close to the localized shear zones. After the initial peak stress, steady stress values of 250 MPa were measured. We intend to focus on how the localized zones evolve and how the mechanical response changes with increasing shear strain during the reaction.

Coupling of Oceanic and Continental Crust During Eocene Eclogite-Facies Metamorphism: Evidence From the Monte Rosa Nappe, Western Alps, Italy

NASA Astrophysics Data System (ADS)

Lapen, T. J.; Johnson, C. M.; Baumgartner, L. P.; Skora, S.; Mahlen, N. J.; Beard, B. L.

2006-12-01

Subduction of continental crust to HP-UHP metamorphic conditions requires overcoming density contrasts that are unfavorable to deep burial, whereas exhumation of these rocks can be reasonably explained through buoyancy-assisted transport in the subduction channel to more shallow depths. In the western Alps, both continental and oceanic lithosphere has been subducted to eclogite-facies metamorphic conditions. The burial and exhumation histories of these sections of lithosphere bear directly on the dynamics of subduction and the stacking of units within the subduction channel. We address the burial history of the continental crust with high precision U-Pb rutile and Lu-Hf garnet geochronology of the eclogite-facies Monte Rosa nappe (MR), western Alps, Italy. U-Pb rutile ages from quartz-carbonate-white mica-rutile veins that are hosted within eclogite and schist of the MR, Gressoney Valley, Italy, indicate that it was at eclogite-facies metamorphic conditions at 42.6 +/- 0.6 Ma. The sample area (Indren glacier, Furgg zone; Dal Piaz, 2001) consists of eclogite boudins that are surrounded by micaceous schist. Associated with the eclogite and schist are quartz-carbonate-white mica-rutile veins that formed in tension cracks in the eclogite and along the contact between eclogite and surrounding schist. Intrusion of the veins occurred at eclogite-facies metamorphic conditions (480-570°C, >1.3-1.4 GPa) based on textural relations, oxygen isotope thermometry, and geothermobarometry. Lu-Hf geochronology of garnet from a chloritoid-talc-garnet-phengite-quartz-calcite-pyrite - chalcopyrite bearing boudin within talc-chloritoid whiteschists of the MR, Val d'Ayas, Italy (Chopin and Monie, 1984; Pawlig, 2001) yields an age of 40.54 +/- 0.36 Ma. The talc-chloritoid whiteschists from the area record pressures and temperatures of 1.6-2.4 GPa and 500-530°C (Chopin and Monie, 1984; Le Bayon et al., 2006) indicating near UHP metamorphic conditions. Based on the age, P-T, and textural data, the rutile age likely represents the prograde-leg of the eclogite-facies P-T path whereas the Lu-Hf garnet age likely represents higher grade metamorphic conditions. The timing of eclogite-facies metamorphism in the MR is within the same time interval as the duration of prograde metamorphism (~55-40) recorded in the structurally overlying Zermatt-Saas ophiolite (ZSO; e.g., Amato et al., 1999; Lapen et al., 2003; Mahlen et al., this meeting). In particular, the Lu-Hf garnet age from the MR is identical within error to a relatively young 40.8 +/- 1.8 Ma Lu-Hf garnet-whole rock-cpx age from a structurally low slice of the ZSO at Saas-Fee, Switzerland (Mahlen et al., this meeting). Not only do the ages of eclogite-facies metamorphism overlap between the MR and ZSO, but so do the P-T conditions (e.g., between 1.6-2.8 GPa; 500-600°C). These data, combined with the relative structural positions of the MR and ZSO in the western Alps, suggest that the MR and ZSO were likely juxtaposed within the subduction channel through underplating of the MR beneath the ZSO. The strong negative buoyancy of the MR has likely aided in the exhumation of sections of the ZSO. Therefore, coupling of continental and oceanic terranes in a subduction channel, perhaps a general feature in the western Alps, may be critical in preventing permanent loss of oceanic crust to the mantle.

Provenance and composition of unusually chrome and nickel-rich bucket-shaped pottery from Rogaland (southwestern Norway)

NASA Astrophysics Data System (ADS)

Zimmermann, Udo; Kristoffersen, Elna Siv; Fredriksen, Per Ditlef; Bertolino, Silvana A. R.; Andò, Sergio; Bersani, Danilo

2016-05-01

We report results from FE-SEM-EDS, geochemical, mineralogical analyses and Raman spectroscopy of pottery of bucket-shaped ceramic from Rogaland (southwestern Norway) dated between the 5th and 6th Century. The study reveals a very rare pottery composition including asbestos-group minerals and an unusual enrichment in compatible elements like Cr (8-27 × Post Archean average shale (PAS), McLennan et al., 2006), Ni (2-8 × normal shale) and Co (2-3 × PAS). X-Rray diffraction and Raman spectroscopy could pinpoint that Ni is introduced by specific Ni-rich talc mineral and chlorite minerals and Cr occurs in a rare Cr-rich talc, and possibly in a Cr-chlorite, these minerals are the most abundant in the pottery, which is supported by strong enrichment in Mg (10-20 × PAS). The addition of Mg, Cr, Ni and Co and other compatible trace elements is to our current knowledge not caused by anthropogenic activity but related to the used materials, which are alteration products of mafic and ultramafic rocks or genetically related to mafic and ultramafic rocks. Rocks of this type are exposed in vicinity of the sampling areas in a region called Karmøy, hosting a world famous ophiolite complex, which is identified as the major source for the mafic and ultramafic component, as the next succession of a similar composition is far further north located in Norway and a number of rock types on Karmøy matches the chemical composition of the pottery. The here reported composition is spectacular and extremely rare - if ever found - in pottery. Our study shows that unusual material sources have been used in pottery production, and this opens for discussion whether the materials were deliberately selected by the manufacturers, thereby expressing a specific social function, in a time period where more functional clay types and additives, and certainly functional and sufficient for use in pottery, where abundant in areas of Rogaland closer to where the pots were found.

Micromechanics of Friction in a Detailed Study of Mg-rich Phyllosilicates

NASA Astrophysics Data System (ADS)

Sanchez Roa, C.; Faulkner, D.; Boulton, C. J.; Jimenez Millan, J.; Nieto, F.

2016-12-01

Phyllosilicate minerals commonly occur within faults, which may accommodate slip either aseismically via creep mechanisms or seismically in earthquakes. The Mg-rich phyllosilicates talc, saponite, sepiolite, and palygorskite have different crystallography and habits. Sepiolite and palygorskite are fibrous due to their discontinuous tetrahedral layers, while saponite and talc are platy due to the continuity of their TOT and water layers. Friction experiments were conducted in a triaxial apparatus under 95 MPa effective normal stress with water and argon as pore fluids. Results show a marked contrast between friction coefficients of fibrous phyllosilicates, 0.57 to 0.63 for argon experiments and 0.4 to 0.5 for water-saturated experiments, and platy Mg-rich phyllosilicates, as low as 0.22 for argon experiments and 0.04 for water-saturated experiments. During velocity steps (where sliding velocity is increased or decreased by one order of magnitude), the two mineral groups exhibit distinctly dissimilar behaviours. After the direct effect of the change in sliding rate, fibrous phyllosilicates show a rapid exponential decay towards a new friction coefficient (a positive b value). Meanwhile, the friction coefficient of the platy phyllosilicates has a more linear evolution (a zero, or negative b value). This effect could be related to a difference in the sliding strength of the contact asperities which would be much higher for crystal surfaces of fibrous minerals with an indented surface due to the silicon tetrahedra inversions. The fibre-shaped crystals may consequently require higher amounts of volumetric work against the normal stress (dilatancy). SEM and TEM observations of the deformed samples showed a well-developed network of R1 Riedel shears in the fibrous materials; planar phyllosilicates show a more homogeneous matrix and incipient development of P foliation. Planar phyllosilicate grains align on their basal planes facilitating intergranular sliding, in contrast, the fibrous phyllosilicates appear to form an interlocking grid-like network that may promote dilatancy during velocity steps. The contrasting strength of Mg-rich phyllosilicates and analysis of their microstructures imply that phyllosilicate habit strongly influences the micromechanics of frictional sliding.

Isolation, characterization, and formulation of antagonistic bacteria for the management of seedlings damping-off and root rot disease of cucumber.

PubMed

Khabbaz, Salah Eddin; Abbasi, Pervaiz A

2014-01-01

Antagonistic bacteria are common soil inhabitants with potential to be developed into biofungicides for the management of seedling damping-off, root rot, and other soil-borne diseases of various crops. In this study, antagonistic bacteria were isolated from a commercial potato field and screened for their growth inhibition of fungal and oomycete pathogens in laboratory tests. The biocontrol potential of the 3 most effective antagonistic bacteria from the in vitro tests was evaluated against seedling damping-off and root rot of cucumber caused by Pythium ultimum. Based on phenotypic characteristics, biochemical tests, and sequence analysis of 16S-23S rDNA gene, the 3 antagonistic bacteria were identified as Pseudomonas fluorescens (isolate 9A-14), Pseudomonas sp. (isolate 8D-45), and Bacillus subtilis (isolate 8B-1). All 3 bacteria promoted plant growth and suppressed Pythium damping-off and root rot of cucumber seedlings in growth-room assays. Both pre- and post-planting application of these bacteria to an infested peat mix significantly increased plant fresh masses by 113%-184% and percentage of healthy seedlings by 100%-290%, and decreased damping-off and root rot severity by 27%-50%. The peat and talc formulations of these antagonistic bacteria applied as seed or amendment treatments to the infested peat mix effectively controlled Pythium damping-off and root rot of cucumber seedlings and enhanced plant growth. The survival of all 3 antagonistic bacteria in peat and talc formulations decreased over time at room temperature, but the populations remained above 10(8) CFU/g during the 180-day storage period. The peat formulation of a mixture of 3 bacteria was the best seed treatment, significantly increasing the plant fresh masses by 245% as compared with the Pythium control, and by 61.4% as compared with the noninfested control. This study suggests that the indigenous bacteria from agricultural soils can be developed and formulated as biofungicides for minimizing the early crop losses caused by seedling damping-off and root rot diseases.

A development roadmap for critical technologies needed for TALC: a deployable 20m annular space telescope

NASA Astrophysics Data System (ADS)

Sauvage, Marc; Amiaux, Jérome; Austin, James; Bello, Mara; Bianucci, Giovanni; Chesné, Simon; Citterio, Oberto; Collette, Christophe; Correia, Sébastien; Durand, Gilles A.; Molinari, Sergio; Pareschi, Giovanni; Penfornis, Yann; Sironi, Giorgia; Valsecchi, Giuseppe; Verpoort, Sven; Wittrock, Ulrich

2016-07-01

Astronomy is driven by the quest for higher sensitivity and improved angular resolution in order to detect fainter or smaller objects. The far-infrared to submillimeter domain is a unique probe of the cold and obscured Universe, harboring for instance the precious signatures of key elements such as water. Space observations are mandatory given the blocking effect of our atmosphere. However the methods we have relied on so far to develop increasingly larger telescopes are now reaching a hard limit, with the JWST illustrating this in more than one way (e.g. it will be launched by one of the most powerful rocket, it requires the largest existing facility on Earth to be qualified). With the Thinned Aperture Light Collector (TALC) project, a concept of a deployable 20 m annular telescope, we propose to break out of this deadlock by developing novel technologies for space telescopes, which are disruptive in three aspects: • An innovative deployable mirror whose topology, based on stacking rather than folding, leads to an optimum ratio of collecting area over volume, and creates a telescope with an eight times larger collecting area and three times higher angular resolution compared to JWST from the same pre-deployed volume; • An ultra-light weight segmented primary mirror, based on electrodeposited Nickel, Composite and Honeycomb stacks, built with a replica process to control costs and mitigate the industrial risks; • An active optics control layer based on piezo-electric layers incorporated into the mirror rear shell allowing control of the shape by internal stress rather than by reaction on a structure. We present in this paper the roadmap we have built to bring these three disruptive technologies to technology readiness level 3. We will achieve this goal through design and realization of representative elements: segments of mirrors for optical quality verification, active optics implemented on representative mirror stacks to characterize the shape correction capabilities, and mechanical models for validation of the deployment concept. Accompanying these developments, a strong system activity will ensure that the ultimate goal of having an integrated system can be met, especially in terms of (a) scalability toward a larger structure, and (b) verification philosophy.

Decrypting the Formation Conditions of the Basement Carbonate-Bearing Rocks at Nili Fossae

NASA Astrophysics Data System (ADS)

Brown, A. J.

2015-12-01

The Nili Fossae region is the site of a number of proposed Landing Sites for the Mars 2020 Rover. A distinguishing feature of many of these sites is the access to large exposures of carbonate (Ehlmann et al. 2008). Serpentinization has been proposed as a formation mechanism of these carbonates, including carbonated (Brown et al. 2010, Viviano, et al. 2013) and low temperature, near surface serpentinization. The potential for carbonated serpentization at Nili Fossae links the region to Earth analogs in terrestrial greenstone belts such as the Pilbara in Western Australia, where talc-carbonate bearing komatiite cumulate units of the Dresser Formation overlie the siliceous, stromatolite-bearing Strelley Pool Chert unit (Van Kranendonk and Pirajno, 2004). If a similar relationship exists on Mars, investigations of rocks stratigraphically beneath the carbonate-bearing units at Nili Fossae ("the basement rocks") may provide the best chance to examine well preserved organic material from the Noachian. This hypothesis is testable by Mars 2020. In preparation for the the Mars 2020 landing site, we are examining the thermodynamic relationships that favor formation of serpentine and talc-carbonate and different pressures and temperatures in the crust (Barnes 2007). This will allow us to constrain the low grade metamorphism required to replicate the proposed models of serpentinisation and help us understand the regional metamophic gradient that is critical to furthering our knowledge of the ancient rocks of Nili Fossae. Refs:Barnes, S. J. "Komatiites: Petrology, Volcanology, Metamorphism, and Geochemistry." S.E.G. 13 (2007): 13. Brown, A. J., et al.. "Hydrothermal Formation of Clay-Carbonate Alteration Assemblages in the Nili Fossae Region of Mars." EPSL 297 (2010): 174-82. Ehlmann, B. L. et al. "Orbital Identification of Carbonate-Bearing Rocks on Mars." Science 322, no. 5909 1828-32. Van Kranendonk, M.J., and F. Pirajno. "Geochemistry of Metabasalts and Hydrothermal Alteration Zones Associated with Ca. 3.45 Ga Chert+/- Barite Deposits" GEEA 4, no. 3 (2004): 253-78. Viviano, C. E., et al. "Implications for Early Hydrothermal Environments on Mars through the Spectral Evidence for Carbonation and Chloritization Reactions in the Nili Fossae Region." JGR 118, no. 9 (2013): 1858-72.

The influence of oxalate-promoted growth of saponite and talc crystals

USGS Publications Warehouse

Schumann, Dirk; Hartman, Hyman; Eberl, Dennis D.; Sears, S. Kelly; Hesse, Reinhard; Vali, Hojatollah

2013-01-01

The intercalating growth of new silicate layers or metal hydroxide layers in the interlayer space of other clay minerals is known from various mixed-layer clay minerals such as illite-smectite (I-S), chlorite-vermiculite, and mica-vermiculite. In a recent study, the present authors proposed that smectite-group minerals can be synthesized from solution as new 2:1 silicate layers within the low-charge interlayers of rectorite. That study showed how oxalate catalyzes the crystallization of saponite from a silicate gel at low temperatures (60ºC) and ambient pressure. As an extension of this work the aim of the present study was to test the claim that new 2:1 silicate layers can be synthesized as new intercalating layers in the low-charge interlayers of rectorite and whether oxalate could promote such an intercalation synthesis. Two experiments were conducted at 60ºC and atmospheric pressure. First, disodium oxalate solution was added to a suspension of rectorite in order to investigate the effects that oxalate anions have on the structure of rectorite. In a second experiment, silicate gel of saponitic composition (calculated interlayer charge −0.33 eq/O10(OH)2) was mixed with a suspension of rectorite and incubated in disodium oxalate solution. The synthesis products were extracted after 3 months and analyzed by X-ray diffraction and high-resolution transmission electron microscopy (HRTEM). The treatment of ultrathin sections with octadecylammonium (nC = 18) cations revealed the presence of 2:1 layer silicates with different interlayer charges that grew from the silicate gel. The oxalate-promoted nucleation of saponite and talc crystallites on the rectorite led to the alteration and ultimately to the destruction of the rectorite structure. The change was documented in HRTEM lattice-fringe images. The crystallization of new 2:1 layer silicates also occurred within the expandable interlayers of rectorite but not as new 2:1 silicate layers parallel to the previous 2:1 silicate layers. Instead, they grew independently of any orientation predetermined by the rectorite crystal substrate and their crystallization was responsible for the destruction of the rectorite structure.

Curing mechanism of flexible aqueous polymeric coatings.

PubMed

Irfan, Muhammad; Ahmed, Abid Riaz; Kolter, Karl; Bodmeier, Roland; Dashevskiy, Andriy

2017-06-01

The objective of this study was to explain curing phenomena for pellets coated with a flexible polymeric coating based on poly(vinyl acetate) (Kollicoat® SR 30D) with regard to the effect of starter cores, thickness of drug layer, adhesion of coating to drug-layered-cores as well as coating properties. In addition, appropriate approaches to eliminate the curing effect were identified. Sugar or MCC cores were layered with the model drugs carbamazepine, theophylline, propranolol HCl, tramadol HCl and metoprolol HCl using HPMC (5 or 25% w/w, based on drug) as a binder. Drug-layered pellets were coated with Kollicoat® SR 30D in a fluidized bed coater using TEC (10% w/w) as plasticizer and talc (35-100% w/w) as anti-tacking agent. Drug release, pellet properties (morphology, water uptake-weight loss and osmolality) and adhesion of the coating to the drug layer were investigated as a function of curing at 60°C or 60°C/75% RH for 24h. The film formation of the aqueous dispersion of Kollicoat® SR 30D was complete, and therefore, a strong curing effect (decrease in drug release) at elevated temperature and humidity (60°C/75% RH) could not be explained by the well-known hydroplasticization and the further gradual coalescence of the colloidal polymer particles. According to the provided mechanistic explanation, the observed curing effect was associated with (1) high flexibility of coating, (2) adhesion between coating and drug layer, (3) water retaining properties of the drug layer, and (4) osmotically active cores. Unwanted curing effects could be minimized/eliminated by the addition of talc or/and pore-forming water soluble polymers in the coating, increasing binder amount or applying an intermediate coating, by increasing the thickness of drug layer or using non-osmotic cores. A new insight into curing phenomena mainly associated with the adhesion between drug layer and coating was provided. Appropriate approaches to avoid unwanted curing effect were identified. Copyright © 2017 Elsevier B.V. All rights reserved.

IgG4-related pleural disease presenting as a massive bilateral effusion.

PubMed

Ishida, Atsuko; Furuya, Naoki; Nishisaka, Takashi; Mineshita, Masamichi; Miyazawa, Teruomi

2014-07-01

A 74-year-old woman with massive bilateral pleural effusion, which was exudative in nature, and with mononuclear cell predominance underwent a pleuroscopy. Parietal pleura were thickened and partly reddish in color. Biopsy specimens taken from the parietal pleura revealed lymphoplasmacytic inflammation with fibrosis. As her performance status rapidly worsened with thoracentesis, we performed bilateral pleurodesis using talc. Pathologic evaluation of the pleural biopsy specimen with immunohistochemical staining revealed 91 IgG4-positive plasma cells per high-power field and an IgG4/IgG ratio of 91%. Thus, the diagnosis of pleuritis from IgG4-related disease was established. Our case suggests that IgG4-related disease is one of the causes of pleural effusion, and it should be included in the differential diagnosis of unexplained pleuritis.

Zero-order release of aspirin, theophylline and atenolol in water from novel methylcellulose glutarate matrix tablets.

PubMed

Khairuzzaman, A; Ahmed, S U; Savva, M; Patel, N K

2006-08-02

A novel hydrocolloidal polymer, methylcellulose glutarate (MC-GA), was prepared by esterifying methylcellulose with glutaric anhydride. The formation of ester was confirmed by FTIR and NMR spectroscopy, DSC and elemental analysis. The physicochemical properties such as, rate of swelling in water, viscosity and hygroscopicity of MC-GA were determined and compared with those of methycellulose A (MC). Aspirin, theophylline and atenolol tablets were compacted on a Carver press using the wet granulation method. Each tablet contained: 200 mg active, 80 mg anhydrous lactose, 8 mg povidone, 4 mg magnesium stearate, 4 mg talc, 50mg MC or MC-GA (drug-to-polymer ratio, 4:1). Contrary to the first-order release profile of all the drugs from the MC matrix tablets, a zero-order release was obtained from the MC-GA matrix tablets in water.

Mixed-layer kerolite/stevensite from the Amargosa Desert, Nevada

USGS Publications Warehouse

Eberl, Dennis D.; Jones, Blair F.; Khoury, Hani N.

1982-01-01

Mixed-layer clays composed of randomly interstratified kerolite/stevensite occur as lake and/or spring deposits of probable Pliocene and Pleistocene age in the Amargosa Desert of southern Nevada, U.S.A. The percentage of expandable layers of these clays, determined from computer-simulated X-ray diffractograms, ranges from almost 0 to about 80%. This range in expandabilities most likely results from differences in solution chemistry and/or temperature at the time of formation. An average structural formula for the purest clay (sample P-7), a clay with about 70% expandable layers, is:[(Mg2.72Al0.07Fe0.03Li0.09)(Si3.96Al0.04)O10(OH)0.2]-0.21[X+0.21]+0.21The data suggest that talc, kerolite, and stevensite form a continuous structural series based on layer charge.

Supplement a to compilation of air pollutant emission factors. Volume 1. Stationary point and area sources. Fifth edition

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-02-01

This Supplement to AP-42 addresses pollutant-generating activity from Bituminous and Subbituminous Coal Combustion; Anthracite Coal Combustion; Fuel Oil Combustion; Natural Gas Combustion; Wood Waste Combustion in Boilers; Lignite Combustion; Waste Oil Combustion: Stationary Gas Turbines for Electricity Generation; Heavy-duty Natural Gas-fired Pipeline Compressor Engines; Large Stationary Diesel and all Stationary Dual-fuel engines; Natural Gas Processing; Organic Liquid Storage Tanks; Meat Smokehouses; Meat Rendering Plants; Canned Fruits and Vegetables; Dehydrated Fruits and Vegetables; Pickles, Sauces and Salad Dressing; Grain Elevators and Processes; Cereal Breakfast Foods; Pasta Manufacturing; Vegetable Oil Processing; Wines and Brandy; Coffee Roasting; Charcoal; Coal Cleaning; Frit Manufacturing; Sandmore » and Gravel Processing; Diatomite Processing; Talc Processing; Vermiculite Processing; paved Roads; and Unpaved Roads. Also included is information on Generalized Particle Size Distributions.« less

Pleural malignancies.

PubMed

Vargas, F S; Teixeira, L R

1996-07-01

Carcinoma of the lung, metastatic breast carcinoma, and lymphoma are responsible for approximately 75% of all malignant pleural effusions. The presence of malignant cells in the pleural fluid or in the parietal pleura confirms the diagnosis. Recently, several authors have proposed the combination of morphometric procedures and quantitative analysis of nucleolar organizer regions stained by silver nitrate. Videothoracoscopy is recommended for patients suspected of having a malignant pleural effusion in whom the diagnosis is not established after two cytologic studies of the fluid and one needle biopsy. The standard treatment is the intrapleural instillation of a chemical agent to produce a pleurodesis. The recommended sclerosant is talc, a tetracycline derivative, or Corynebacterium parvum where it is available. When a patient is not an ideal candidate for chemical pleurodesis, the options include symptomatic treatment, serial thoracentesis, implantation of a pleuroperitoneal shunt, and pleurectomy.

[The assessment of surgical treatment of patients with malignant pleural effusion].

PubMed

Lazarev, S M; Reshetov, A V; Kakysheva, O E; Nikolaev, G V; Kirillov, Iu V; Volgin, G N

2013-01-01

An analysis of results of 498 patients with malignant pleural effusion was made. All patients were divided into three groups depending on methods of treatment: in the first group of patients the puncture of pleural cavity and the evacuation of liquid were made against the background of complex treatment; in the second group of patients the thoracocentesis and suspension induction were performed; in the third group the video thoracoscopy was carried out. In an assessment of each method of treatment, the researchers came to the conclusion that in case when the patient had the sufficient functional capabilities, the doctors should give preference to the thoracoscopy operations and in case of severe somatic status the doctors should give preference to the drainage of pleural cavity with release from exudates and with subsequent introduction of talc as the most effective sclerosing agent.

Engineering fungal morphology for enhanced production of hydrolytic enzymes by Aspergillus oryzae SBS50 using microparticles.

PubMed

Singh, Bijender

2018-06-01

Effect of microparticles and silver nanoparticles was studied on the production of hydrolytic enzymes by a potent phytase-producing mould, Aspergillus oryzae SBS50. Addition of microparticles, viz. talc powder and aluminum oxide enhanced phytase production from 2894 to 3903 and 2847 to 4204 U/L, cellulase from 2529 to 4931 and 2455 to 3444 U/L, xylanase from 9067 to 9642 and 9994 to 14,783 U/L, amylase from 5880 to 11,000 and 6130 to 13,145 U/L, respectively. Fungal morphology was also engineered by the use of microparticles. Fungal pellet size was significantly reduced (~ 90%) by the addition of microparticles. Fermentation time was reduced from 4 to 3 days after the addition of microparticles, thus increasing the productivity of the enzymes significantly. These results confirmed the importance of microparticles in engineering fungal morphology for enhanced production of hydrolytic enzymes.

Ancient hydrothermal seafloor deposits in Eridania basin on Mars

NASA Astrophysics Data System (ADS)

Michalski, Joseph R.; Dobrea, Eldar Z. Noe; Niles, Paul B.; Cuadros, Javier

2017-07-01

The Eridania region in the southern highlands of Mars once contained a vast inland sea with a volume of water greater than that of all other Martian lakes combined. Here we show that the most ancient materials within Eridania are thick (>400 m), massive (not bedded), mottled deposits containing saponite, talc-saponite, Fe-rich mica (for example, glauconite-nontronite), Fe- and Mg-serpentine, Mg-Fe-Ca-carbonate and probable Fe-sulphide that likely formed in a deep water (500-1,500 m) hydrothermal setting. The Eridania basin occurs within some of the most ancient terrain on Mars where striking evidence for remnant magnetism might suggest an early phase of crustal spreading. The relatively well-preserved seafloor hydrothermal deposits in Eridania are contemporaneous with the earliest evidence for life on Earth in potentially similar environments 3.8 billion years ago, and might provide an invaluable window into the environmental conditions of early Earth.

The mineral base and productive capacities of metals and non-metals of Kosovo

NASA Astrophysics Data System (ADS)

Rizaj, M.; Beqiri, E.; McBow, I.; O'Brien, E. Z.; Kongoli, F.

2008-08-01

All historical periods of Kosovo—Ilirik, Roman, Medieval, Turkish, and former Yugoslavian—are linked with the intensive development of mining and metallurgy. This activity influenced and still is influencing the overall position of Kosovo as a country. For example, according to a 2006 World Bank report as well as other studies, Kosovo has potential lignite resources (geological reserves) of about 1.5 billion tonnes, which are ranked fifth in the world in importance. Other significant Kosovan mineral resources include lead, zinc, gold, silver, bauxite, and uranium, and rare metals accompanying those minerals, including indium, cadmium, thallium, gallium, and bismuth. These rare metals are of particular importance in developing advanced industrial technologies. Kosovo also has reserves of high-quality non-metals, including magnesite, quartz grit, bentonite, argil, talc, and asbestos. No database exists for these non-metal reserves, and further research and studies are needed.

Aminopropyl-modified magnesium-phyllosilicates: layered solids with tailored interlayer access and reactivity.

PubMed

Ferreira, Ricardo B; da Silva, César R; Pastore, Heloise O

2008-12-16

Despite its wide application, the synthesis of aminopropyl-modified magnesium-phyllosilicates was known only in the case where every silicon atom bore an organic pending group. This paper shows the preparation of aminopropyl-modified talc where tailored amounts of silicon atoms are bound to an aminopropyl group. The decrease in the concentration of the organoamino group leaves a proportional concentration of interlayer SiOH groups that can be used to react with other silylation agents. The amino group reacts with CO2, forming a carbamate functionality; it seems that the presence of this group avoids delamination in water as performed for the parent compound. Bearing in mind that the aminopropyl group can be changed by other groups, the present synthesis strategy demonstrates ways to produce solids with controlled surface properties with interlayer amino and SiOH groups in variable concentrations, allowing formation of several other interlayer functionalities.

The mineral base and productive capacities of metals and non-metals of Kosovo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rizaj, M.; Beqiri, E.; McBow, I.

2008-08-15

All historical periods of Kosovo - Ilirik, Roman, Medieval, Turkish, and former Yugoslavian - are linked with the intensive development of mining and metallurgy. This activity influenced and still is influencing the overall position of Kosovo as a country. For example, according to a 2006 World Bank report as well as other studies, Kosovo has potential lignite resources (geological reserves) of about 1.5 billion tonnes, which are ranked fifth in the world in importance. Other significant Kosovan mineral resources include lead, zinc, gold, silver, bauxite, and uranium, and rare metals accompanying those minerals, including indium, cadmium, thallium, gallium, and bismuth.more » These rare metals are of particular importance in developing advanced industrial technologies. Kosovo also has reserves of high-quality non-metals, including magnesite, quartz grit, bentonite, argil, talc, and asbestos. No database exists for these non-metal reserves, and further research and studies are needed.« less

Application of tumbling melt granulation (TMG) method to prepare controlled-release fine granules.

PubMed

Maejima, T; Kubo, M; Osawa, T; Nakajima, K; Kobayashi, M

1998-03-01

The tumbling melt granulation (TMG) method was applied to prepare controlled-release fine granules of diltiazem hydrochloride (DH). The entire process, from the preparation of the cores by the adherence of DH to the sucrose crystal to the subsequent coating of the controlled-release layer, was performed without using any solvent. A mixture of meltable material, talc, and ethylcellulose was used for the controlled-release layer and controlled-release fine granules approximately 400 microns in diameter were obtained with excellent producibility. The dissolution rate of DH from these fine granules was similar to that of a once-a-day dosage form obtained in the market; further, the dependency of the dissolution profile on pH of the media was less. Thus, it was concluded that this TMG method was very useful for preparing not only controlled-release beads of granule size (usually 500 to 1400 microns) but also fine granules.

The preventive effect of Daikenchuto on postoperative adhesion-induced intestinal obstruction in rats.

PubMed

Tokita, Y; Satoh, K; Sakaguchi, M; Endoh, Y; Mori, I; Yuzurihara, M; Sakakibara, I; Kase, Y; Takeda, S; Sasaki, H

2007-04-01

The present study investigated the effect of Daikenchuto (DKT) on postoperative intestinal adhesion in rats. We evaluated the effects of DKT, constituent medical herbs and active compounds on talc-induced intestinal adhesion in rats and DKT-induced contractions using isolated guinea pig ileum. DKT significantly prevented adhesion formation, and this action was inhibited by pretreatment with atropine or ruthenium red. The constituent medical herbs, Zanthoxylum Fruit and Maltose Syrup Powder significantly prevented adhesion formation. Moreover, hydroxy sanshool (HS) prevented adhesion formation, and this action was inhibited by pretreatment with ruthenium red. In contrast, DKT-induced contractions were inhibited by tetrodotoxin, atropine, and capsazepine. These results suggested that DKT had a preventive action on postoperative adhesive intestinal obstruction, and that this action was mediated by sensory and cholinergic nerves. Furthermore, HS was found to be one of the active compound of DKT, and its action was mediated by sensory nerves.

The Relation Between Lung Dust and Lung Pathology in Pneumoconiosis*

PubMed Central

Nagelschmidt, G.

1960-01-01

Methods of isolation and analysis of dust from pneumoconiotic lungs are reviewed, and the results of lung dust analyses for different forms of pneumoconiosis are presented. A tentative classification separates beryllium, aluminium, abrasive fume, and asbestos, which cause interstitial or disseminated fibrosis from quartz, coal, haematite, talc, kaolin, and other dusts, which cause a nodular or focal fibrosis which may change to forms with massive lesions. The data suggest that in the first, but not in the second, group the dusts are relatively soluble; only in the second group do amounts of dust and severity of fibrosis go in parallel for a given form of pneumoconiosis. In classical silicosis the quartz percentage is higher and the amount of total dust much lower than in coal-miners' pneumoconiosis. Mixed forms of both groups occur, for instance, in diatomite workers. The need for more research, especially in the first group, is pointed out. Images PMID:13727444

X-ray texture analysis of paper coating pigments and the correlation with chemical composition analysis

NASA Astrophysics Data System (ADS)

Roine, J.; Tenho, M.; Murtomaa, M.; Lehto, V.-P.; Kansanaho, R.

2007-10-01

The present research experiments the applicability of x-ray texture analysis in investigating the properties of paper coatings. The preferred orientations of kaolin, talc, ground calcium carbonate, and precipitated calcium carbonate particles used in four different paper coatings were determined qualitatively based on the measured crystal orientation data. The extent of the orientation, namely, the degree of the texture of each pigment, was characterized quantitatively using a single parameter. As a result, the effect of paper calendering is clearly seen as an increase on the degree of texture of the coating pigments. The effect of calendering on the preferred orientation of kaolin was also evident in an independent energy dispersive spectrometer analysis on micrometer scale and an electron spectroscopy for chemical analysis on nanometer scale. Thus, the present work proves x-ray texture analysis to be a potential research tool for characterizing the properties of paper coating layers.

Reaction-induced rheological weakening enables oceanic plate subduction.

PubMed

Hirauchi, Ken-Ichi; Fukushima, Kumi; Kido, Masanori; Muto, Jun; Okamoto, Atsushi

2016-08-26

Earth is the only terrestrial planet in our solar system where an oceanic plate subducts beneath an overriding plate. Although the initiation of plate subduction requires extremely weak boundaries between strong plates, the way in which oceanic mantle rheologically weakens remains unknown. Here we show that shear-enhanced hydration reactions contribute to the generation and maintenance of weak mantle shear zones at mid-lithospheric depths. High-pressure friction experiments on peridotite gouge reveal that in the presence of hydrothermal water, increasing strain and reactions lead to an order-of-magnitude reduction in strength. The rate of deformation is controlled by pressure-solution-accommodated frictional sliding on weak hydrous phyllosilicate (talc), providing a mechanism for the 'cutoff' of the high peak strength at the brittle-plastic transition. Our findings suggest that infiltration of seawater into transform faults with long lengths and low slip rates is an important controlling factor on the initiation of plate tectonics on terrestrial planets.

Ancient hydrothermal seafloor deposits in Eridania basin on Mars

PubMed Central

Michalski, Joseph R.; Dobrea, Eldar Z. Noe; Niles, Paul B.; Cuadros, Javier

2017-01-01

The Eridania region in the southern highlands of Mars once contained a vast inland sea with a volume of water greater than that of all other Martian lakes combined. Here we show that the most ancient materials within Eridania are thick (>400 m), massive (not bedded), mottled deposits containing saponite, talc-saponite, Fe-rich mica (for example, glauconite-nontronite), Fe- and Mg-serpentine, Mg-Fe-Ca-carbonate and probable Fe-sulphide that likely formed in a deep water (500–1,500 m) hydrothermal setting. The Eridania basin occurs within some of the most ancient terrain on Mars where striking evidence for remnant magnetism might suggest an early phase of crustal spreading. The relatively well-preserved seafloor hydrothermal deposits in Eridania are contemporaneous with the earliest evidence for life on Earth in potentially similar environments 3.8 billion years ago, and might provide an invaluable window into the environmental conditions of early Earth. PMID:28691699

Systemic candidiasis in mice. II.--Main role of polymorphonuclear leukocytes in resistance to infection.

PubMed

Hurtrel, B; Lagrange, P H; Michel, J C

1980-01-01

Cyclophosphamide (CY) increased whereas the talc embedded in a calcium phosphate gel (TCP) decreased the susceptibility of mice to systemic candidiasis estimated by measuring mean survival time and "renal infectivity" 12 h after challenge. Transfers of plasma from CY- and TCP-treated mice did not modify cnadidiasis susceptibility of recipient mice. Granulopenia and granulocytosis induced respectively by CY and TCP were significantly correlated with susceptibility or resistance to candidiasis. Nevertheless, TCP produced significant reticuloendothelial stimulation which could be also correlated with TCP protection. Reticuloendothelial stimulation with associated granulopenia in TCP-CY-treated mice gave protection against Listeria monocytogenes challenge but not against Candida albicans. Thus, blood polymorphonuclear leukocytes seem to play the main role in natural resistance of mice to candidiasis. This was corroborated after injection of immunostimulants; a good correlation was found between C. albicans resistance and the induced granulocytosis.

Formation of organoclays by a one step synthesis

NASA Astrophysics Data System (ADS)

Jaber, Maguy; Miéhé-Brendlé, Jocelyne; Delmotte, Luc; Le Dred, Ronan

2005-05-01

Different lamellar hybrid inorganic-organic materials having as inorganic parent 2:1 (T.O.T.) phyllosilicates such as talc, saponite, pyrophyllite, beidellite and montmorillonite were prepared by a one step synthesis. The solids were characterized by X-ray diffraction, solid state 29Si, 27Al, and 19F nuclear magnetic resonance and transmission electron microscopy. XRD patterns show that solids with inorganic parents having octahedral sheet based on aluminium exhibit a lamellar structure similar to MCM-50, whereas those with magnesium have an organophyllosilicate structure. In the first case, the absence of hexacoordinated aluminium was confirmed by 27Al NMR and an ordered stacking of the layers is observed on TEM micrographs. In opposite, a disorder is observed on the TEM images of organophyllosilicates. The formation of the 2:1 structure was found to be controlled mainly by the insertion of silicic species in the interlamellar space of brucite like layers.

Soap-stone in architecture of North European cities. A nomination as a candidate for a Global Heritage Stones Resource

NASA Astrophysics Data System (ADS)

Bulakh, Andrey

2016-04-01

Soap stone represents soft Proterozoic rock type from the deposit Nunnalahti situated on the western shore of the big Lake Pielinen in Eastern Finland. It consists of talc (40 - 50 %), magnesite MgCO3 (40 - 50 %), chlorite (5 - 8 %), dolomite, calcite, etc. The colour of the stone is very spectacular and varies from yellow and brownish-yellow to grey, greenish grey. The soft stone is a highly workable material for a sculptor's chisel. It was one of the most popular ornamental rocks used architecture of the Modern style in St Petersburg, Helsinki, Turku, Tampere and other North European cities lately in the XIX-th centuries. Examples are given and discussed. References: Bulakh, A.G., Abakumova, N.B., and Romanovsky, J.V. St Petersburg: a History in Stone. 2010. Print House of St Petersburg State University. 173 p. (In English).

Analysis of airborne imaging spectrometer data for the Ruby Mountains, Montana, by use of absorption-band-depth images

NASA Technical Reports Server (NTRS)

Brickey, David W.; Crowley, James K.; Rowan, Lawrence C.

1987-01-01

Airborne Imaging Spectrometer-1 (AIS-1) data were obtained for an area of amphibolite grade metamorphic rocks that have moderate rangeland vegetation cover. Although rock exposures are sparse and patchy at this site, soils are visible through the vegetation and typically comprise 20 to 30 percent of the surface area. Channel averaged low band depth images for diagnostic soil rock absorption bands. Sets of three such images were combined to produce color composite band depth images. This relative simple approach did not require extensive calibration efforts and was effective for discerning a number of spectrally distinctive rocks and soils, including soils having high talc concentrations. The results show that the high spectral and spatial resolution of AIS-1 and future sensors hold considerable promise for mapping mineral variations in soil, even in moderately vegetated areas.

Serpentinization as a reactive transport process: The brucite silicification reaction

NASA Astrophysics Data System (ADS)

Tutolo, Benjamin M.; Luhmann, Andrew J.; Tosca, Nicholas J.; Seyfried, William E.

2018-02-01

Serpentinization plays a fundamental role in the biogeochemical and tectonic evolution of the Earth and perhaps many other rocky planetary bodies. Yet, geochemical models still fail to produce accurate predictions of the various modes of serpentinization, which limits our ability to predict a variety of related geological phenomena over many spatial and temporal scales. Here, we use kinetic and reactive transport experiments to parameterize the brucite silicification reaction and provide fundamental constraints on SiO2 transport during serpentinization. We show that, at temperatures characteristic of the sub-seafloor at the serpentinite-hosted Lost City Hydrothermal Field (150 °C), the assembly of Si tetrahedra onto MgOH2 (i.e., brucite) surfaces is a rate-limiting elementary reaction in the production of serpentine and/or talc from olivine. Moreover, this reaction is exponentially dependent on the activity of aqueous silica (a SiO2 (aq)), such that it can be calculated according to the rate law:

Oxygen and hydrogen isotope fractionation in serpentine-water and talc-water systems from 250 to 450 °C, 50 MPa

USGS Publications Warehouse

Saccocia, Peter J.; Seewald, Jeffrey S.; Shanks, Wayne C.

2009-01-01

Oxygen and hydrogen isotope fractionation factors in the talc–water and serpentine–water systems have been determined by laboratory experiment from 250 to 450 °C at 50 MPa using the partial exchange technique. Talc was synthesized from brucite + quartz, resulting in nearly 100% exchange during reaction at 350 and 450 °C. For serpentine, D–H exchange was much more rapid than 18O–16O exchange when natural chrysotile fibers were employed in the initial charge. In experiments with lizardite as the starting charge, recrystallization to chrysotile enhanced the rate of 18O–16O exchange with the coexisting aqueous phase. Oxygen isotope fractionation factors in both the talc–water and serpentine–water systems decrease with increasing temperature and can be described from 250 to 450 °C by the relationships: 1000 ln  = 11.70 × 106/T2 − 25.49 × 103/T + 12.48 and 1000 ln  = 3.49 × 106/T2 − 9.48 where T is temperature in Kelvin. Over the same temperature interval at 50 MPa, talc–water D–H fractionation is only weakly dependent on temperature, similar to brucite and chlorite, and can be described by the equation: 1000 ln  = 10.88 × 106/T2 − 41.52 × 103/T + 5.61 where T is temperature in Kelvin. Our D–H serpentine–water fractionation factors calibrated by experiment decrease with temperature and form a consistent trend with fractionation factors derived from lower temperature field calibrations. By regression of these data, we have refined and extended the D–H fractionation curve from 25 to 450 °C, 50 MPa as follows: 1000 ln  = 3.436 × 106/T2 − 34.736 × 103/T + 21.67 where T is temperature in Kelvin. These new data should improve the application of D–H and 18O–16O isotopes to constrain the temperature and origin of hydrothermal fluids responsible for serpentine formation in a variety of geologic settings.

H partitioning between NAMs in garnet-bearing peridotite at subsolidus conditions

NASA Astrophysics Data System (ADS)

Demouchy, S. A.; Shcheka, S.; Denis, C. M. M.; Thoraval, C.

2017-12-01

Hydrogen distribution between nominally anhydrous minerals (NAMs) of a garnet-lherzolite under subsolidus conditions has been investigated. Separated NAMs from a garnet-peridotite from Patagonia (Chile) are annealed together (olivine, orthopyroxene, clinopyroxene and garnet) using a piston-cylinder at 3 GPa and 1100 °C using talc-Pyrex cell assembly for 10, 25 and 100 hours. The talc-pyrex assembly provides enough hydrogen in the system to re-equilibrate the hydrogen concentrations at high pressure. The three co-existing nominally anhydrous minerals (NAMs, i.e., olivine, orthopyroxene and clinopyroxene) were successfully analyzed using FTIR. The resulting hydrogen concentrations exceed significantly the initial hydrogen concentration by a factor of 13 for olivine and a factor of 3 for both pyroxenes. Once mineral-specific infrared calibrations are applied, the average concentrations in NAMs are 115±12 ppm wt H2O for olivine, 635±75 ppm wt H2O for orthopyroxene and 1214±137 ppm wt H2O for clinopyroxene, garnet grains are dry. Since local equilibrium seems achieved over time (for 100 hours), the calculated concentration ratios are interpreted as mineral-to-mineral hydrogen partition coefficients (i.e., Nernst `s law) for a garnet-peridotite assemblage. It yields, based on mineral-specific infrared calibrations, Dopx/ol=5±1, Dcpx/ol= 10±2, and Dcpx/opx=1.9±0.4. While Dcpx/opx is in agreement (within error) with previous results from experimental studies and concentration ratios observed in mantle-derived peridotites, the Dpx/ol from this study are significantly lower than the values reported from mantle-derived xenoliths and also at odd with several previous experimental studies where melt and/or hydrous minerals co-exists with NAMs. The results confirm the sensitivity of hydrogen incorporation in olivine regarding the amount of water-derived species (H) in the system and/or the amount of water in the co-existing silicate melt. The results are in agreement with an important but incomplete dehydration of mantle-derived olivine occurring at depth, during transport by the host magma or during slow lava flow cooling at the surface. The rapid concentration modification in mantle pyroxenes also points out that pyroxenes might not be a hydrogen recorder as reliable as previously thought.

Organic- and carbonate-rich soil formation ˜2.6 billion years ago at Schagen, East Transvaal district, South Africa

NASA Astrophysics Data System (ADS)

Watanabe, Yumiko; Stewart, Brian W.; Ohmoto, Hiroshi

2004-05-01

A ˜17-m paleosol sequence at Schagen, South Africa, which developed on a serpentinized dunite intrusion in a granite-gneiss terrain ˜2.6 Ga ago, is characterized by an alternating succession of thick (˜1-3 m) carbonate-rich (dolomite and calcite) zones and silicate-rich (serpentines, talc, and quartz) zones; the upper ˜8 m section is especially rich in organic C (up to ˜1.4 wt.%). Petrologic and geochemical data suggest the upper ˜8 m section is composed of at least three soil profiles that developed on: (i) silicate-rich rock fragments (and minerals) that were transported from local sources (serpentinite and granite) by fluvial and/or eolian processes; and (ii) dolomite and calcite zones that formed by locally discharged groundwater. The Mg and Fe in the paleosol sequence were largely supplied from local sources (mostly serpentinite), but the Ca, Sr, and HCO 3- were supplied by groundwater that originated from a surrounding granite-gneiss terrain. In the uppermost soil profile, the (Fe is retained, the Fe 3+/Fe 2+ ratio increases, and ferri-stilpnomelane is abundant. These data suggest the atmospheric pO 2 was much greater than ˜10 -3.7 atm (>0.1% present atmospheric level [PAL]). The carbonaceous matter in the soils is intimately associated with clays (talc, chlorite, and ferri-stilpnomelane) and occurs mostly as seams (20 μm to 1 mm thick) that parallel the soil horizons. These occurrences, crystallographic structures, H/C ratios, and δ 13C org values (-17.4 to -14.4‰ PDB) suggest that the carbonaceous matter is a remnant of in situ microbial mats, originally ˜1 to ˜20 mm thick. The microbial mats developed: (a) mostly on soil surfaces during the formation of silicate-rich soils, and (b) at the bottom of an evaporating, anoxic, alkaline pond during the precipitation of the Fe-rich dolomite. These δ 13C org values are difficult to be explained by a current popular idea of a methane- and organic haze-rich Archean atmosphere (Pavlov et al., 2001); these values, however, can be easily explained if the microbial mats were composed of cyanobacteria and heterotrophs that utilized the remnants of cyanobacteria in a strongly evaporating environment.

Prograde and retrograde metamorphic processes in high-pressure subduction zone serpentinites from East Thessaly, Greece

NASA Astrophysics Data System (ADS)

Koutsovitis, Petros

2016-04-01

The East Thessaly region, Central Greece, includes metaophiolitic mélange formations which extend from the eastern foothills of Mt. Olympus and Ossa, throughout the Agia basin, Mt. Mavrovouni (Sklithro region), South Pelion and reaching up to northeast Othris (regions of Aerino and Velestino). They appear in the form of dispersed and deformed thrust sheets having been variably emplaced onto Mesozoic platform series rocks of the Pelagonian tectonostratigraphic zone[1]. These formations consist mainly of serpentinites, as well as metasediments, metagabbros, metadolerites, rodingites, ophicalcites, talc-schists and chromitites. Based upon petrographic observations, mineral chemistry data and XRD patterns, the subduction zone-related serpentinites from the regions of Potamia, Anavra, Aetolofos and Kalochori-Chasanbali (Agia basin), as well as from the regions of Aerino and Velestino, are characterized by the progressive transformation of lizardite to antigorite and are distinguished into two groups. The first group includes serpentinites from the metaophiolitic formations of Potamia, Anavra, Aerino and Velestino, which are marked by destibillization of lizardite to antigorite, mostly along the grain boundaries of the lizardite mesh textured relics. The presence of lizardite and antigorite in almost equal amounts indicates medium-temperature blueschist facies metamorphic conditions (˜340-370 ° C; P≈10-11 kbar)[2,3,4]. The second serpentinite group appears in the regions of Aetolofos and Kalochori, characterized by the predominance of antigorite, the minor occurrence of lizardite and the complete replacement of spinel by Cr-magnetite. The absence of metamorphic olivine suggests that these serpentinites were most likely formed at slightly higher temperature and pressure conditions compared to the first serpentinite group, corresponding to medium or high temperature blueschist facies metamorphism (˜360-380 ° C; P≈12 kbar)[2,3,4]. These metamorphic conditions are highly comparable with the P-T estimates from the East Thessaly metabasic rocks (˜350 ° C; P≈10-11 kbars)[5], suggesting that the entire metaophiolitic formation underwent blueschist facies metamorphism, comparable with high-pressure metaophiolitic formations appearing in Evia, Attica and the Cyclades. The East Thessaly serpentinites exhibit significantly high PM-normalized Pb, U enrichments and rather high Cs, La, As and Sb concentrations, which are comparable with subduction-related serpentinites, formed after mantle wedge peridotite hydration, and that have interacted with sedimentary derived fluids [2,6,7,8]. These serpentinites were also partly affected by de-serpentinization retrograde metamorphism (estimated at P<8 kbar and T<350 ° C) which is noticed by the following: secondary crosscuting antigorite veins occasionally with chlorite, coronas of chlorite along Cr-magnetite crystals, appearance of secondary calcite veins and talc. In the Kalochori-Chasanbali area, intense carbonization processes formed ophicalcite breccias enveloped by imbricated serpentinites[9], whereas talc-rich serpentinites appear in the region of Sklithro. Retrograde metamorphism may have occurred during exhumation, possibly within a serpentinite channel[8]. In addition, their retrograde history can also be indirectly identified through the study of their rodingite intrusions and more specifically through the formation of late-stage vesuvianite-rich dykes at low-moderate temperature conditions (T=250-300 oC) and subsequent derodingitization processes, forming metarodingites. The latter include abundant high-Mg replacive chlorite formed by continuous serpentinization which provided Mg2+ to the infiltrating fluids, causing the partial breakdown of Ca-bearing minerals. References. [1] Pe-Piper & Piper 2002: Borntraeger, Stuttgart, 1-645; [2] Lafay et al 2013: Chem Geol 343, 38-54; [3] Schwartz et al 2013: Lithos 178, 197-210; [4] Guillot, et al 2015: Tectonophysics 646, 1-19; [5] Perraki et al 2002: Geologica Carpathica 53, 164-165; [6] Deschamps, et al 2013: Lithos 178, 96-127; [7] Hattori & Guillot, 2007: G-Cubed 8 (9); [8] Barnes et al 2014: Chemi Geol 389, 29-47; [9] Melfos et al 2009: Geoph. Res. Abst, 11.

Chromite and other mineral deposits in serpentine rocks of the Piedmont Upland, Maryland, Pennsylvania, and Delaware

USGS Publications Warehouse

Pearre, Nancy C.; Heyl, Allen V.

1960-01-01

The Piedmont Upland in Maryland, Pennsylvania, and Delaware is about 160 miles long and at the most 50 miles wide. Rocks that underlie the province are the Baltimore gneiss of Precambrian age and quartzite, gneiss, schist, marble, phyllite, and greenstone, which make up the Glenarm series of early Paleozoic (?) age. These are intruded by granitic, gabbroic, and ultramaflc igneous rocks. Most of the ultramaflc rocks, originally peridotite, pyroxenite, and dunite, have been partly or completely altered to serpentine and talc; they are all designated by the general term serpentine. The bodies of serpentine are commonly elongate and conformable with the enclosing rocks. Many have been extensively quarried for building, decorative, and crushed stone. In addition, chromite, titaniferous magnetite, rutile, talc and soapstone, amphibole asbestos, magnesite, sodium- rich feldspar (commercially known as soda spar), and corundum have been mined or prospected for in the serpentine. Both high-grade massive chromite and lower grade disseminated chromite occur in very irregular and unpredictable form in the serpentine, and placer deposits of chromite are in and near streams that drain areas underlain by serpentine. A group of unusual minerals, among them kammererite, are typical associates of high-grade massive chromite but are rare in lower grade deposits. Chromite was first discovered in the United States at Bare Hills, Md., around 1810. Between 1820 and 1850, additional deposits were discovered and mined in Maryland and Pennsylvania, including the largest deposit of massive chromite ever found in the United States the Wood deposit, in the State Line district. A second period of extensive chromite mining came during the late 1860's and early 1870's. Production figures are incomplete and conflicting. Estimates from the available data indicate that the aggregate production from 27 of 40 known mines before 1900 totaled between 250,000 and 280,000 tons of lode-chromite ore; information is lacking for the other 13. Placer deposits produced considerably more than 15,000 tons of chromite concentrates. Exploratory work in several of the mines and placer deposits during World War I produced about 1,500 long tons of chromite ore, 920 tons of which was sold.Most of the chromite from Maryland and Pennsylvania was used to manufacture chemical compounds, pigments, and dyes before metallurgical and refractory uses for chromite were developed. Available analyses of the ores indicate that they would satisfy modern requirements for chemical-grade chromite. With the exception of such deposits as the Line Pit and Red Pit mines, the chromite contains too much iron for the best metallurgical grade, but many would be satisfactory low-grade metallurgical chromite. Perhaps 30,000 to 50,000 tons of chromite concentrates that would range from 30 to 54 percent Cr2O3 could be obtained from placer deposits in the State Line and Soldiers Delight districts. A small tonnage of chromite remains in dumps at six of the old mines. Lode and placer deposits in the Philadelphia district, placers in Montgomery County, Md., and possible downward extensions of known ore bodies below the floors of high-grade mines now flooded have not been completely explored. Although other chromite deposits probably lie concealed at relatively shallow depths, no practical method of finding them has been developed.Small deposits of titaniferous iron ore in serpentine were mined for iron before 1900, but the titanium content troubled furnace operators. Ore bodies are similar in occurrence to chromite deposits; they are massive or disseminated and are found near the edges of serpentine intrusive rocks. The small size of the deposits and comparatively low titanium content limit their importance as a potential source of titanium. A single rutile deposit in Harford County, Md., has been prospected but not mined. Pockets in schistose chlorite rock, probably altered from pyroxenite, contain as much as 16 percent rutile and average 8 percent. Rutile-bearing rock has been proved to a depth of about 58 feet. Talc and soapstone deposits that have been worked in the State Line and Jarrettsville-Dublin districts are the result of steatitization of serpentine at its contact with intrusive sodium-rich pegmatites. Deposits in the Marriottsville and Philadelphia districts seem to be related to shear or crush zones in the serpentine, which served as channelways for steatitizing solutions. Massive soapstone was extensively used in the 19th century for furnace, fireplace, and stove linings and for washtubs and bathtubs. Every year from 1906 until 1960 talc and soapstone have been produced from one or more of the deposits in Maryland and Pennsylvania. Deposits near Dublin and Marriottsville, Md., have produced steadily for years and production continues. Lava-grade steatite from Dublin, Md., is manufactured into ceramic products for electrical and refractory purposes. Slip-fiber amphibole asbestos deposits were known in the area as early as 1837, but early production was limited. The product was used mostly for linings of safes, boiler covers, and paints. During World War I the demand for domestic asbestos for chemical filters led to further development of deposits in Maryland. Between 1916 and 1940 many small veins of good-quality tremolite and anthophyllite were mined, and the fiber was prepared for market at Woodlawn, Md. Only the upper parts of veins, softened by weathering, were usable. Because prospecting was reportedly fairly thorough and known deposits are said to be mined out, and because demand for amphibole asbestos is limited, the possibility of future asbestos production from the area seems small, except as a byproduct of talc quarrying. Magnesite from several mines in Pennsylvania and Maryland was much in demand between 1828 and 1871 for the manufacture of epsom salt. Exploratory work at the old Goat Hill mines in 1921 indicated that the product could not be profitably prepared for market at that time. Although reportedly high grade, the magnesite veins are thin and small in comparison with other domestic deposits.Sodium-rich feldspar and corundum deposits occur in pegmatites that are unusual because they characteristically contain little or no quartz and mica and because, insofar as known, they are confined to serpentine rocks. Many of the known deposits of sodium-rich feldspar commercial soda-spar are reportedly mined out. It is possible, however, that other commercial deposits will be found in the area. At various times from 1825 until about 1892 in Pennsylvania, corundum mined or found at the surface was used to meet a demand of the abrasives industry. The increased use of artificial abrasives has diminished the demand for natural corundum, and interest in the small, irregular Pennsylvania deposits is at present largely historical or mineralogical.

Successful model for cooperative student learning centers in physics and astronomy

NASA Astrophysics Data System (ADS)

Bieniek, Ronald J.; Johnson, John A.

2003-04-01

We have established successful problem-based learning centers for introductory courses in physics [1] and astronomy [2] that fully implement the Seven Principles of Good Practice in Undergraduate Education [3] without increased demand on faculty time. Large percentages of students at our two institutions voluntarily utilize these learning venues. Course instructors guide self-forming groups of students to mastery of technical concepts and skills, building greater student self-confidence through direct interaction and feedback. The approach's immediacy helps students recognize ambiguities in their understanding, thereby increasing impact at teachable moments. Underperforming students are assisted along side students who wish to hone their skills. The format also facilitates racial and gender mixing within learning center camaraderie. Specific pedagogical and operational techniques for running learning centers will be presented. [1] http://www.umr.edu/ physics/plc [2] http://astron.berkeley.edu/talc.html [3] A.W. Chickering & Z.F. Gamson, Am. Assoc. Higher Ed. Bulletin, 1987, 39(7) 3-7.

Differential diagnosis of granulomatous lung disease: clues and pitfalls: Number 4 in the Series "Pathology for the clinician" Edited by Peter Dorfmüller and Alberto Cavazza.

PubMed

Ohshimo, Shinichiro; Guzman, Josune; Costabel, Ulrich; Bonella, Francesco

2017-09-30

Granulomatous lung diseases are a heterogeneous group of disorders that have a wide spectrum of pathologies with variable clinical manifestations and outcomes. Precise clinical evaluation, laboratory testing, pulmonary function testing, radiological imaging including high-resolution computed tomography and often histopathological assessment contribute to make a confident diagnosis of granulomatous lung diseases. Differential diagnosis is challenging, and includes both infectious (mycobacteria and fungi) and noninfectious lung diseases (sarcoidosis, necrotising sarcoid granulomatosis, hypersensitivity pneumonitis, hot tub lung, berylliosis, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, rheumatoid nodules, talc granulomatosis, Langerhans cell histiocytosis and bronchocentric granulomatosis). Bronchoalveolar lavage, endobronchial ultrasound-guided transbronchial needle aspiration, transbronchial cryobiopsy, positron emission tomography and genetic evaluation are potential candidates to improve the diagnostic accuracy for granulomatous lung diseases. As granuloma alone is a nonspecific histopathological finding, the multidisciplinary approach is important for a confident diagnosis. Copyright ©ERS 2017.

The geologic relationships of industrial mineral deposits and asbestos in the western united states

USGS Publications Warehouse

VanGosen, B.S.

2009-01-01

In recent years, U.S. regulatory agencies have placed emphasis on identifying and regulating asbestos dust exposures in the mining environment, with a particular focus upon industrial mineral deposits in which asbestos occurs as an accessory mineral. Because asbestos minerals form in specific geologic environments, only certain predictable types of industrial mineral deposits can potentially host asbestos mineralization. By applying a basic knowledge of asbestos geology, the costly and time consuming efforts of asbestos monitoring and analyses can be directed towards those mineral deposit types most likely to contain asbestos mineralogy, while saving efforts on the mineral deposits that are unlikely to contain asbestos. While the vast majority of industrial mineral deposits in the Western United States are asbestos-free, there are several types that can, in some instances, host asbestos mineralization, or be closely associated with it. These industrial mineral deposits include a few types of aggregate, dimension, and decorative stone, and some deposits of chromite-nickel, magnesite, nepheline syenite, olivine, rare earth elements, talc, vermiculite, and wollastonite.

Improved cell disruption of Pichia pastoris utilizing aminopropyl magnesium phyllosilicate (AMP) clay.

PubMed

Kim, Sun-Il; Wu, Yuanzheng; Kim, Ka-Lyun; Kim, Geun-Joong; Shin, Hyun-Jae

2013-06-01

An efficient method for Pichia cell disruption that employs an aminopropyl magnesium phyllosilicate (AMP) clay-assisted glass beads mill is presented. AMP clay is functionalized nanocomposite resembling the talc parent structure Si8Mg6O20(OH)4 that has been proven to permeate the bacterial membrane and cause cell lysis. The recombinant capsid protein of cowpea chlorotic mottle virus (CCMV) expressed in Pichia pastoris GS115 was used as demonstration system for their ability of self-assembly into icosahedral virus-like particles (VLPs). The total protein concentration reached 4.24 mg/ml after 4 min treatment by glass beads mill combined with 0.2 % AMP clay, which was 11.2 % higher compared to glass beads mill only and the time was half shortened. The stability of purified CCMV VLPs illustrated AMP clay had no influence on virus assembly process. Considering the tiny amount added and simple approach of AMP clay, it could be a reliable method for yeast cell disruption.

Adsorption of dextrin on hydrophobic minerals.

PubMed

Beaussart, Audrey; Mierczynska-Vasilev, Agnieszka; Beattie, David A

2009-09-01

The adsorption of dextrin on talc, molybdenite, and graphite (three naturally hydrophobic minerals) has been compared. Adsorption isotherms and in situ tapping mode atomic force microscope (TMAFM) imaging have enabled polymer adsorbed amount and morphology of the adsorbed layer (area coverage and polymer domain size) to be determined and also the amount of hydration water in the structure of the adsorbed layer. The effect of the polymer on the mineral contact angles, measured by the captive bubble method on cleaved mineral surfaces, indicates clear correlations between the hydrophobicity reduction of the minerals, the adsorbed amount, and the surface coverage of the adsorbed polymer. Predictions of the flotation recovery of the treated mineral phases have been confirmed by performing batch flotation experiments. The influence of the polymer surface coverage on flotation recovery has highlighted the importance of this key parameter in the predictions of depressant efficiency. The roles of the initial hydrophobicity and the surface structure of the mineral basal plane in determining adsorption parameters and flotation response of the polymer-treated minerals are also discussed.

Mineral resource assessment of the Dillon 1 degree x 2 degrees Quadrangle, Idaho and Montana

USGS Publications Warehouse

Pearson, Robert Carl; Trautwein, C.M.; Ruppel, E.T.; Hanna, W.F.; Rowan, L.C.; Loen, J.S.; Berger, B.R.

1992-01-01

The Dillon 1°x2° quadrangle in southwestern Montana and east-central Idaho was investigated as part of the U.S. Geological Survey's Conterminous United States Mineral Assessment Program (CUSMAP) to determine its mineral resource potential. An interdisciplinary study was made of geology, geochemistry, geophysics (gravity and aeromagnetics), remote sensing, and mineral deposits. The results of those studies, as well as mineral resource assessment of numerous mineraldeposit types, are published separately as a folio of maps. This report summarizes the studies, provides background information on them, and presents a selected bibliography relevant to the geology and mineral resources of the quadrangle. The quadrangle contains large resources of gold and substantial resources of talc and chlorite, all of which were being mined in the 1980's and early 1990's. Submarginal resources of molybdenum, copper, tungsten, and iron range from moderately large to large. Other commodities that may be present in significant amounts are chromite, lead, zinc, silver, barite, zeolite minerals, and various nonmetallic metamorphic minerals.

Reaction-induced rheological weakening enables oceanic plate subduction

PubMed Central

Hirauchi, Ken-ichi; Fukushima, Kumi; Kido, Masanori; Muto, Jun; Okamoto, Atsushi

2016-01-01

Earth is the only terrestrial planet in our solar system where an oceanic plate subducts beneath an overriding plate. Although the initiation of plate subduction requires extremely weak boundaries between strong plates, the way in which oceanic mantle rheologically weakens remains unknown. Here we show that shear-enhanced hydration reactions contribute to the generation and maintenance of weak mantle shear zones at mid-lithospheric depths. High-pressure friction experiments on peridotite gouge reveal that in the presence of hydrothermal water, increasing strain and reactions lead to an order-of-magnitude reduction in strength. The rate of deformation is controlled by pressure-solution-accommodated frictional sliding on weak hydrous phyllosilicate (talc), providing a mechanism for the ‘cutoff' of the high peak strength at the brittle-plastic transition. Our findings suggest that infiltration of seawater into transform faults with long lengths and low slip rates is an important controlling factor on the initiation of plate tectonics on terrestrial planets. PMID:27562366

Is air pollution causing landslides in China?

NASA Astrophysics Data System (ADS)

Zhang, Ming; McSaveney, Mauri J.

2018-01-01

Air pollution in China often exceeds "unhealthy" levels, but Chinese air is not only a threat from being breathed: the pollutants may also be causing fatal landslides. Very acid rain from severe air pollution falls widely in southwest China, where coal is a major energy source. We discuss where acid rain may provide an unsuspected link between mining and the fatal 2009 Jiweishan landslide in southwest China; it may have reduced the strength of a thin, calcareous, black sapropelic shale in Jiweishan Mountain by removing cementing carbonate minerals and sapropel matrix. Mining beneath the potential slide mass may not have directly triggered the landslide, but collapse of abandoned adits drained a perched aquifer above a regional black-shale aquiclude. Inflow of acid, oxygenated water and nutrients into the aquiclude may have accelerated the reduction of strength of the weakest rocks and consequently led to rapid sliding of a large rock mass on a layer of weathered shale left composed largely of soft, and slippery talc.

Aqueous Geochemical Dynamics at the Coast Range Ophiolite Microbial Observatory and The Case for Subsurface Mixing of Regional Groundwaters

NASA Astrophysics Data System (ADS)

Cardace, D.; Schrenk, M. O.; McCollom, T. M.; Hoehler, T. M.

2017-12-01

Serpentinization is the aqueous alteration (or hydration) of olivine and pyroxene minerals in ultramafic rocks, occurring in the seabed and ultramafic units on continents, such as at the Coast Range Ophiolite (CRO) in northern California, USA. Mineral products of serpentinization include serpentine, magnetite, brucite, talc, oxyhydroxides, carbonates, and diverse clay minerals. Such mineral transformations generate extremely high pH solutions with characteristic cation and dissolved metal loads, transmitting CH4, H2, and CO gas mixtures from depth; deep life in ultramafic terrains is thought to be fueled by chemical energy derived from these geochemical reactions. The installation of 8 groundwater monitoring wells in the CRO has allowed frequent monitoring since 2011. Influx of deeply sourced, serpentinization-influenced waters is evidenced by related geochemical shifts (e.g., pH, oxidation-reduction potential), but is apparently mixing with other, regionally important groundwater types. Evaluation salinity loads in concert with other parameters, we model the mixing scenario of this site of ongoing scientific study and experimentation.

A Mapping of the Electron Localization Function for Earth Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gibbs, Gerald V.; Cox, David F.; Ross, Nancy

2005-06-01

The electron localization function, ELF, generated for a number of geometry-optimized earth materials, provides a graphical representation of the spatial localization of the probability electron density distribution as embodied in domains ascribed to localized bond and lone pair electrons. The lone pair domains, displayed by the silica polymorphs quartz, coesite and cristobalite, are typically banana-shaped and oriented perpendicular to the plane of the SiOSi angle at ~0.60 Å from the O atom on the reflex side of the angle. With decreasing angle, the domains increase in magnitude, indicating an increase in the nucleophilic character of the O atom, rendering itmore » more susceptible to potential electrophilic attack. The Laplacian isosurface maps of the experimental and theoretical electron density distribution for coesite substantiates the increase in the size of the domain with decreasing angle. Bond pair domains are displayed along each of the SiO bond vectors as discrete concave hemispherically-shaped domains at ~0.70 Å from the O atom. For more closed-shell ionic bonded interactions, the bond and lone pair domains are often coalesced, resulting in concave hemispherical toroidal-shaped domains with local maxima centered along the bond vectors. As the shared covalent character of the bonded interactions increases, the bond and lone pair domains are better developed as discrete domains. ELF isosurface maps generated for the earth materials tremolite, diopside, talc and dickite display banana-shaped lone pair domains associated with the bridging O atoms of SiOSi angles and concave hemispherical toroidal bond pair domains associated with the nonbridging ones. The lone pair domains in dickite and talc provide a basis for understanding the bonded interactions between the adjacent neutral layers. Maps were also generated for beryl, cordierite, quartz, low albite, forsterite, wadeite, åkermanite, pectolite, periclase, hurlbutite, thortveitite and vanthoffite. Strategies are reviewed for finding potential H docking sites in the silica polymorphs and related materials. As observed in an earlier study, the ELF is capable of generating bond and lone pair domains that are similar in number and arrangement to those provided by Laplacian and deformation electron density distributions. The formation of the bond and lone pair domains in the silica polymorphs and the progressive decrease in the SiO length as the value of the electron density at the bond critical point increases indicates that the SiO bonded interaction has a substantial component of covalent character.« less

Metamorphic reprocessing of a serpentinized carbonate-bearing peridotite after detachment from the mantle wedge: A P-T path constrained from textures and phase diagrams in the system CaO-MgO-Al 2O 3-SiO 2-CO 2-H 2O

NASA Astrophysics Data System (ADS)

Mposkos, E.; Baziotis, I.; Proyer, A.

2010-08-01

In the central Rhodope mountains of Greece a carbonate-bearing metaperidotite lens ˜ 200 × 500 m in size crops out as part of the high- to ultrahigh-pressure metamorphic Upper Sidironero Complex ˜ 500 m SE of the Gorgona Village, north of Xanthi town. It is composed primarily of coarse grained (3-20 mm in size) olivine and orthopyroxene, medium grained clinohumite and medium to fine grained tremolite, chlorite, dolomite, magnesite, talc, antigorite and various spinel phases. Whole-rock chemistry, mineral textures and compositions, and phase diagram calculations show that the metaperidotite was subjected to a prograde HP metamorphism, isofacial with the surrounding migmatitic gneisses, metapelites and amphibolites. The prograde character of metamorphism is demonstrated by inclusions of talc, antigorite, chlorite, dolomite, magnesite and Ti-clinohumite in ferrit-chromite, olivine, and orthopyroxene, as well as of olivine in orthopyroxene, and by the typical change in composition of zoned spinel minerals from ferrit-chromite in the core to chromian spinel at the rim. The prograde path is characterized by successive growth of amphibole, Ti-clinohumite, olivine and orthopyroxene, followed by the breakdown of Ti-clinohumite to olivine + Mg-ilmenite and of chlorite to olivine + spinel, probably during exhumation. The construction of a partial petrogenetic P- T grid in the system CaO-MgO-Al 2O 3-SiO 2-CO 2-H 2O (CMASCH) for Ca-poor ultramafic bulk compositions has proven highly useful for the reconstruction of the metamorphic evolution and a P- T path, indicating that the use of univariant reactions in mixed volatile systems is highly warranted. The P- T path is clearly constrained to pressures below 1.5-1.7 GPa by the absence of clinopyroxene. These pressures are slightly lower than those recorded in the closely associated Jurassic eclogites and much lower than those recorded in the diamond-bearing gneisses 5 km to the south in the same tectonic unit. The carbonate-bearing metaperidotite from Gorgona probably represents a fragment of the hydrated mantle wedge. This is indicated by the REE compositions which differ from those of ophiolitic peridotites and resemble those of spinel or garnet peridotites of sub-continental origin. The ultramafic slice was incorporated tectonically into the subduction channel, most likely by tectonic erosion in the Early Jurassic, but did not experience ultrahigh-pressure metamorphism like the nearby metapelites that exhumed along the same subduction channel.

Synthesis, properties and applications of bio-based materials

NASA Astrophysics Data System (ADS)

Srinivasan, Madhusudhan

Bio-based feedstock have become very significant as they offer a value proposition in terms of carbon balance and also in terms of endowing biodegradability where needed. Thus a lot of attention is being given to the modification such feedstock for different applications. Soybean oil is one such feedstock. The oil is a triglyceride ester composed of different fatty acids, which are common to other plant oils. Thus soybean oil serves as a platform for plant oils, as modifications of this oil, can in theory be extended to cover other plant oils. Methyl oleate was used as a model fatty acid ester, to synthesize hydroxyesters with ethylene glycol via a two stage oxidative cleavage of the double bonds. Ozone was chosen as the oxidant due to its many advantages. The first stage involved oxidation of the double bond to aldehydes, ozonides and acetals, which were subsequently converted to hydroxyesters (hydroxy values of 220 - 270) in near quantitative yield by treatment with Oxone. This method could be extended to soybean oil to make "polyols" which could find applications in resin syntheses. Silylation was employed as another platform to functionalize soybean oil and fatty acid methyl esters with a reactive silane (vinyltrimethoxy silane). This simple modification produced materials that are cured by atmospheric moisture and are useful as coatings. The silylation was controlled by varying the grafting time, cure temperature and the concentration of the silane. Products with gel content as high as 90% could be achieved. The coating exhibited good adhesion to metal, glass, concrete and paper. Steel panels coated with these coatings exhibited good stability against corrosion in high humidity conditions and moderate stability against a salt spray. The silylation was also successfully utilized to improve the tensile strength of the blend of biodegradable polyester, poly (butylene adipate-co-terephthalate) with talc. A reactive extrusion process was employed to graft vinyl silanes on the polyester in short reaction times of 5 minutes. This improved the compatibility with the talc filler. This biodegradable polyester product was characterized by high tensile strength and moderate elongation. The modification method is simple is applicable to a variety of aliphatic biodegradable polyesters. Finally a rapid polymerization of 1, 4-dioxan-2-one in very short times was accomplished with titanium alkoxides as initiators. At low [monomer]/ [initiator] ratios (100:1), nearly all the alkoxide groups initiated polymerization. High conversions up to 90% were achieved even at high ratios (2400:1). The activation energy for polymerization for titanium tetraisopropoxide is the lowest reported (33.5 kJ/mol) for this monomer system.

Clumped isotope thermometry of calcite and dolomite in a contact metamorphic environment

NASA Astrophysics Data System (ADS)

Lloyd, Max K.; Eiler, John M.; Nabelek, Peter I.

2017-01-01

Clumped isotope compositions of slowly-cooled calcite and dolomite marbles record apparent equilibrium temperatures of roughly 150-200 °C and 300-350 °C, respectively. Because clumped isotope compositions are sensitive to the details of T-t path within these intervals, measurements of the Δ47 values of coexisting calcite and dolomite can place new constraints on thermal history of low-grade metamorphic rocks over a large portion of the upper crust (from ∼5 to ∼15 km depth). We studied the clumped isotope geochemistry of coexisting calcite and dolomite in marbles from the Notch Peak contact metamorphic aureole, Utah. Here, flat-lying limestones were intruded by a pluton, producing a regular, zoned metamorphic aureole. Calcite Δ47 temperatures are uniform, 156 ± 12 °C (2σ s.e.), across rocks varying from high-grade marbles that exceeded 500 °C to nominally unmetamorphosed limestones >5 km from the intrusion. This result appears to require that the temperature far from the pluton was close to this value; an ambient temperature just 20 °C lower would not have permitted substantial re-equilibration, and should have preserved depositional or early diagenetic Δ47 values several km from the pluton. Combining this result with depth constraints from overlying strata suggests the country rock here had an average regional geotherm of 22.3-27.4 °C/km from the late Jurassic Period until at least the middle Paleogene Period. Dolomite Δ47 in all samples above the talc + tremolite-in isograd record apparent equilibrium temperatures of 328-12+13 °C (1σ s.e.), consistent with the apparent equilibrium blocking temperature we expect for cooling from peak metamorphic conditions. At greater distances, dolomite Δ47 records temperatures of peak (anchi)metamorphism or pre-metamorphic diagenetic conditions. The interface between these domains is the location of the 330 °C isotherm associated with intrusion. Multiple-phase clumped isotope measurements are complemented by bulk δ13C and δ18O dolomite-calcite thermometry. These isotopic exchange thermometers are largely consistent with peak temperatures in all samples within 4 km of the contact, indicating that metamorphic recrystallization can occur even in samples too low-grade to produce growth of conventional metamorphic index minerals (i.e., talc and tremolite). Altogether, this work demonstrates the potential of these methods to quantify the conditions of metamorphism at sub-greenschist facies.

Ni cycling in mangrove sediments from New Caledonia

NASA Astrophysics Data System (ADS)

Noël, Vincent; Morin, Guillaume; Juillot, Farid; Marchand, Cyril; Brest, Jessica; Bargar, John R.; Muñoz, Manuel; Marakovic, Grégory; Ardo, Sandy; Brown, Gordon E.

2015-11-01

Covering more than 70% of tropical and subtropical coastlines, mangrove intertidal forests are well known to accumulate potentially toxic trace metals in their sediments, and thus are generally considered to play a protective role in marine and lagoon ecosystems. However, the chemical forms of these trace metals in mangrove sediments are still not well known, even though their molecular-level speciation controls their long-term behavior. Here we report the vertical and lateral changes in the chemical forms of nickel, which accumulates massively in mangrove sediments downstream from lateritized ultramafic deposits from New Caledonia, where one of nature's largest accumulations of nickel occurs. To accomplish this we used Ni K-edge Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy data in combination with microscale chemical analyses using Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM-EDXS). After Principal Component and Target Transform analyses (PCA-TT), the EXAFS data of the mangrove sediments were reliably least-squares fitted by linear combination of 3-components chosen from a large model compound spectral database including synthetic and natural Ni-bearing sulfides, clay minerals, oxyhydroxides, and organic complexes. Our results show that in the inland salt flat Ni is hosted in minerals inherited from the eroded lateritic materials, i.e. Ni-poor serpentine (44-58%), Ni-rich talc (20-31%), and Ni-goethite (18-24%). In contrast, in the hydromorphic sediments beneath the vegetated Avicennia and Rhizophora stands, a large fraction of Ni is partly redistributed into a neoformed smectite pool (20-69% of Ni-montmorillonite), and Ni speciation significantly changes with depth in the sediment. Indeed, Ni-rich talc (25-56%) and Ni-goethite (15-23%) disappear below ∼15 cm depth in the sediment and are replaced by Ni-sorbed pyrite (23-52%) in redox-active intermediate depth layers and by pyrite (34-55%) in the deepest sediment layers. Ni-incorporation in pyrite is especially observed beneath an inland Avicennia stand where anoxic conditions are dominant. In contrast, beneath a Rhizophora stand closer to the ocean, where the redox cycle is intensified due to the tide cycle, partial re-oxidation of Ni-bearing pyrites favors nickel mobility, as confirmed by Ni-mass balance estimates and by higher Ni concentration in the pore waters. These findings have important environmental implications for better evaluating the protective role of mangroves against trace metal dispersion into marine ecosystems. They may also help in predicting the response of mangrove ecosystems to increasing anthropogenic pressure on coastal areas.

Compatibility of Azospirillum brasilense and Pseudomonas fluorescens in growth promotion of groundnut ( Arachis hypogea L.).

PubMed

Prasad, Andhare A; Babu, Subramanian

2017-01-01

We attempted to study the compatibility among plant beneficial bacteria in the culture level by growing them near in the nutrient agar plates. Among all the bacteria tested, Rhizobium was found to inhibit the growth of other bacteria. From the compatible group of PGPR, we have selected one biofertilizer (Azospirillum brasilense strain TNAU) and one biocontrol agent (Pseudomonas fluorescens strain PF1) for further studies in the pot culture. We have also developed a bioformulation which is talc powder based, for individual bacteria and mixed culture. This formulation was used as seed treatment, soil application, seedling root dip and foliar spray in groundnut crop in vitro germination conditions. A. brasilense was found to enhance the tap root growth and P. fluorescens, the lateral root growth. The other growth parameters like shoot growth, number of leaves were enhanced by the combination of both of the bacteria than their individual formulations. Among the method of application tested in our study, soil application was found to be the best in yielding better results of plant growth promotion.

Ultrasound-guided drainages and sclerotherapy.

PubMed

Lohela, P

2002-02-01

Ultrasonically guided fluid collection and abscess drainage have become routine procedures in various parts of the body. In most cases ultrasound is the only imaging and guidance modality needed; however, it is of the utmost importance to remember that CT and fluoroscopy with contrast often give invaluable information when the true extent of the process has to be determined and when assessing the safest route for the catheter in anatomically complicated areas. The importance of irrigation of the abscess cavity with fluids and the ready use of urokinase should be emphasized. Ethanol sclerotherapy is a simple and safe procedure to treat symptomatic hepatic or renal cysts. Parathyroid adenomas and cysts, as well as thyroid cysts, can also be treated with ethanol sclerotherapy in selected cases. Purified mineral talc has been used in pleurodesis and hydrocele sclerotherapy, whereas doxycycline or ethanol is used for postoperative lymphoceles. Both abscess drainages and sclerotherapy procedures are minimally invasive, simple, safe, inexpensive and reasonably efficacious treatment in many clinical instances and may be at least an alternative to surgical treatment, often offering significant advantages over surgery.

Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica

PubMed Central

Ahmed, Khalil; Nizami, Shaikh Sirajuddin; Riza, Nudrat Zahid

2013-01-01

A research has been carried out to develop natural rubber (NR) hybrid composites reinforced with marble sludge (MS)/Silica and MS/rice husk derived silica (RHS). The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc. PMID:25685484

A mineralogical petrographic and geochemical study of samples from wells in the geothermal field of Milos Island (Greece)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liakopoulos, A.

1991-01-01

This paper presents a study of hydrothermal alteration on Milos Island, Greece. Examination of cores and cuttings from the two drill sites, obtained from a depth of about 1100 m in Milos geothermal field, showed that the hydrothermal minerals occurring in the rock include: K-feldspar, albite, chlorite, talc, diopside, epidote, muscovite, tremolite, kaolinite, montmorillonite, alunite, anhydrite, gypsum, calcite, and opaque minerals. The chemical composition of the minerals (104 analyses) was determined with Electron Probe Microanalysis. The composition of the hydrothermal fluid was determined and correlated with the mineralogy. Isotopic ratios of C and O for one calcite sample taken frommore » 341 m depth were determined and used for geochemical calculations. A number of reactions feasible at the P-T conditions of the geothermal field are given to establish the chemical evolution of the hydrothermal fluid. The distribution of the hydrothermal minerals indicates the dilution of the K-, Na- Cl-rich hydrothermal fluid of the deep reservoir by a Ca-, Mg-rich cold water at a shallower level.« less

Speciation of individual mineral particles of micrometer size by the combined use of attenuated total reflectance-Fourier transform-infrared imaging and quantitative energy-dispersive electron probe X-ray microanalysis techniques.

PubMed

Jung, Hae-Jin; Malek, Md Abdul; Ryu, JiYeon; Kim, BoWha; Song, Young-Chul; Kim, HyeKyeong; Ro, Chul-Un

2010-07-15

Our previous work demonstrated for the first time the potential of the combined use of two techniques, attenuated total reflectance FT-IR (ATR-FT-IR) imaging and a quantitative energy-dispersive electron probe X-ray microanalysis, low-Z particle EPMA, for the characterization of individual aerosol particles. In this work, the speciation of mineral particles was performed on a single particle level for 24 mineral samples, including kaolinite, montmorillonite, vermiculite, talc, quartz, feldspar, calcite, gypsum, and apatite, by the combined use of ATR-FT-IR imaging and low-Z particle EPMA techniques. These two single particle analytical techniques provide complementary information, the ATR-FT-IR imaging on mineral types and low-Z particle EPMA on the morphology and elemental concentrations, on the same individual particles. This work demonstrates that the combined use of the two single particle analytical techniques can powerfully characterize externally heterogeneous mineral particle samples in detail and has great potential for the characterization of airborne mineral dust particles.

[Pulmonary intravascular talcosis: A case report].

PubMed

Reverso-Meinietti, J; Vandenbos, F; Risso, K; Coyne, J; Leroy, S; Padovani, B; Burel-Vandenbos, F

2018-04-09

Pulmonary intravascular talcosis is a rare condition occurring in intravenous drug users injecting oral medications. Talc results in a foreign-body granulomatous reaction giving a radiological haematogenic miliary appearance mimicking miliary tuberculosis. Drug users represent a population at risk for both these conditions and their distinction may be challenging. We reported the case of a man, 33 year-old, intravenous drug addict, detected by the health services because he was the partner of a person who died of contagious and multi-resistant tuberculosis. Chest X-ray and CT scan showed a typical miliary appearance. Despite negative microbiology, clinical diagnosis of miliary tuberculosis was retained. Due to the lack of radiological improvement despite appropriate antibiotic treatment, re-evaluation and trans-bronchial biopsy were undertaken. The presence of granulomas centered by birefringent foreign bodies in polarized light led to a diagnosis of pulmonary intravascular talcosis. In the presence of pulmonary miliary in an intravenous drug addict, intravascular talcosis should be suspected. Copyright © 2018 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier SAS. All rights reserved.

Surface modification of porous suspended ceramsite used for water treatment by activated carbon/Fe3O4 magnetic composites.

PubMed

Lu, Mang; Xia, Guang-Hua; Zhao, Xiao-Dong

2013-01-01

In this study, porous suspended ceramsite with a specific density close to that of water was prepared by high-temperature calcination using fly ash, feldspar, calcite, fired talc and kaolin as the raw materials. The ceramsite was modified by activated carbon/Fe3O4 magnetic composites. The optimum modification conditions determined by methylene blue adsorption experiment were: KOH/glucose ratio of 1.5:1, carbonization temperature of 400 degrees C, activation temperature of 850 degrees C, activation time of 1 h, and Fe3O4/KOH+glucose ratio of 1:10. The results demonstrated that the adsorption capacity of the modified ceramsite for methylene blue was significantly higher than that of the unmodified ones. The presence of the composites did not lead to significant decrease in the mechanical properties of the modified ceramsite. Moreover, the modified ceramsite showed good resistance towards acid and alkali. The modified ceramsite can be used as biocarrier and adsorbent for a wide range of contaminants in water and can subsequently be removed from the medium by a simple magnetic procedure.

Electromagnetic interference shielding effectiveness of polypropylene/conducting fiber composites

NASA Astrophysics Data System (ADS)

Lee, Pyoung-Chan; Kim, Bo-Ram; Jeoung, Sun Kyoung; Kim, Yeung Keun

2016-03-01

Electromagnetic released from the automotive electronic parts is harmful to human body. Electromagnetic interference (EMT) shielding refers to the reflection and/or adsorption of electromagnetic radiation by a material, which thereby acts as a shield against the penetration of the radiation through the shield. Polypropylene (PP)/conductive micro fiber composites containing various fiber contents and fiber length were injection-molded. The effect of fiber content and length on electrical properties of the composites was studied by electrical resistivity and EMT shielding measurements. The through-plane electrical conductivity and dielectric permittivity were obtained by measuring dielectric properties. The EMT shielding effectiveness (SE) was investigated by using S-parameter in the range of 100 ~ 1500 MHz. Reflection, absorption and multiple-reflection are the EMT attenuation mechanisms. From the measurement of S-Parameters, the absorption coefficient, reflection coefficient, and the shielding efficiency of the materials were calculated. The EMT SE of PP/conducing fiber composites is 40 dB over a wide frequency range up to 1.5 GHz, which is higher than that of PP/talc composite used automotive parts, viz. 0 dB.

Rapid classification of pharmaceutical ingredients with Raman spectroscopy using compressive detection strategy with PLS-DA multivariate filters.

PubMed

Cebeci Maltaş, Derya; Kwok, Kaho; Wang, Ping; Taylor, Lynne S; Ben-Amotz, Dor

2013-06-01

Identifying pharmaceutical ingredients is a routine procedure required during industrial manufacturing. Here we show that a recently developed Raman compressive detection strategy can be employed to classify various widely used pharmaceutical materials using a hybrid supervised/unsupervised strategy in which only two ingredients are used for training and yet six other ingredients can also be distinguished. More specifically, our liquid crystal spatial light modulator (LC-SLM) based compressive detection instrument is trained using only the active ingredient, tadalafil, and the excipient, lactose, but is tested using these and various other excipients; microcrystalline cellulose, magnesium stearate, titanium (IV) oxide, talc, sodium lauryl sulfate and hydroxypropyl cellulose. Partial least squares discriminant analysis (PLS-DA) is used to generate the compressive detection filters necessary for fast chemical classification. Although the filters used in this study are trained on only lactose and tadalafil, we show that all the pharmaceutical ingredients mentioned above can be differentiated and classified using PLS-DA compressive detection filters with an accumulation time of 10ms per filter. Copyright © 2013 Elsevier B.V. All rights reserved.

[Health impact of indoor mineral particle pollution].

PubMed

Vincent, M; Chemarin, C

2011-04-01

Mineral particle air pollution consists of both atmospheric pollution and indoor pollution. Indoor pollution comes from household products, cosmetics, combustion used to heat homes or cook food, smoking, hobbies or odd jobs. There is strong evidence that acute respiratory infections in children and chronic obstructive pulmonary disease in women are associated with indoor biomass smoke. Detailed questioning is essential to identify at risk activities and sampling of airborne particles may help with the identification of pollution risks. Particle elimination depends on the standard of ventilation of the indoor environment. Five per cent of French homes have levels of pollution greater than 180 μg/m³ for PM 10 and 2% for PM 2.5. The principal mineral particle air pollutants are probably silica, talc, asbestos and carbon, whereas tobacco smoke leads to exposure to various ultrafine particles. The toxicity of these particles could be more related to surface exchange than to density. Tissue measurements by electron microscopy and microanalysis of particle samples may identify an uptake of particles similar to those in the environmental sample. Copyright © 2011. Published by Elsevier Masson SAS.

First Direct Detection of Clay Minerals on Mars

NASA Technical Reports Server (NTRS)

Singer, R. B.; Owensby, P. D.; Clark, R. N.

1985-01-01

Magnesian clays or clay-type minerals were conclusively detected in the martian regolith. Near-IR spectral observations of Mars using the Mauna Kea 2.2-m telescope show weak but definite absorption bands near microns. The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and sponite. There is no spectral evidence for aluminous hydroxylated minerals. No distinct band occurs at 2.55 microns, as would be expected if carbonates were responsible for the 2.35 micron absorption. High-albedo regions such as Elysium and Utopia have the strongest bands near 2.35 microns, as would be expected for heavily weathered soils. Low-albedo regions such as Iapygia show weaker but distinct bands, consistent with moderate coatings, streaks, and splotches of bright weathered material. In all areas observed, the 2.35-micron absorption is at least three times weaker than would be expected if well-crystallized clay minerals made up the bulk of bright soils on Mars.

Oceanic crust within the paleozoic Granjeno Schist, northeastern Mexico. Remnants of the Rheic and paleo-Pacific Ocean.

NASA Astrophysics Data System (ADS)

Torres Sanchez, Sonia Alejandra; Augustsson, Carita; Rafael Barboza Gudiño, Jose; Jenchen, Uwe; Torres Sanchez, Dario; Aleman Gallardo, Eduardo; Abratis, Michael

2015-04-01

Late Paleozoic metamorphic rocks in Mexico are related to the Laurentia-Gondwana collision in Carboniferous time, during Pangaea amalgamation. Vestiges of the Mexican Paleozoic continental configuration are present in the Granjeno Schist, the metamorphic basement of the Sierra Madre Oriental. Field work and petrographic analysis reveal that the Granjeno Schist comprises metamorphic rocks with both sedimentary (psammite, pelite, turbidite, conglomerate, black shale) and igneous (tuff, lava flows, pillow lava and ultramafic bodies) protoliths. The chlorite geothermometer and the presence of phengite in the metasedimentary units as well as 40Ar/39Ar ages on metavolcanic and metaultramafic rocks indicate that the Granjeno Schist was metamorphosed under sub-greenschist to greenschist facies with temperatures ranging from 250-345°C with 2.5 kbar during Carboniferous time (330±30 Ma). The presence of metabasalt, metacumulate, serpentinite and talc bodies suggests an oceanic tectonic setting for the evolution of the Granjeno Schist. Serpetinite rocks have mesh, granular and ribbon textures which indicate recrystallization and metasomatic events. The serpentinite rocks are enriched in the very large incompatible elements Cs, U, and Zr and depleted in Ba, Sr, Pb, Zr and Ce. Normalized REE patterns (LaN/YbN = 0.51 - 19.95 and LaN/SmN = 0.72 - 9.08) of the serpentinite and talc/soapstone are characteristic of peridotite from both suprasubduction and mid-ocean ridge zones. Serpentinite from the Granjeno Schist have spinel content which can reveal different stages of evolution in host serpentinite. The composition of chromite indicates that they belong to podiform chromite that may have crystallized from mid-ocean ridge magma. Al-chromite in the serpentinite is characterized by #Cr 0.48 to 0.55, which indicates a depleted mantle source affected by 17 to 18% of partial melting. The ferritchromite has #Cr values of 0.93 to 1.00 which indicates a metamorphic origin. Our study suggests at least two serpentinization stages. The first serpentinization stage is related to an ocean-floor environment. At this stage, mesh-textured serpentinite formed under static conditions under subgreenschist to greenschist conditions. The second serpentinization stage occurred under greenschist to low amphibole conditions. During this stage Cr-spinel progressively was replaced by ferritchromite with magnetite rims due to regional metamorphism. Tectonic contact of the serpentinite with metavolcanic and metasedimentary rocks indicates lithospheric mantle slivers juxtaposed during the metamorphism of the Granjeno Schist during Pennsylvanian time. This metamorphic event occurred in an active continental margin. It represents the last events of the southern closure of the Rheic Ocean and Permo-Carboniferous convergence of Pacific plates on the western margin of Pangea.

Development of polylactic acid-based materials through reactive modification

NASA Astrophysics Data System (ADS)

Fowlks, Alison Camille

2009-12-01

Polylactic acid (PLA)-based systems have shown to be of great potential for the development of materials requiring biobased content, biodegradation, and sufficient properties. The efforts in this study are directed toward addressing the current research need to overcome some of the inherent drawbacks of PLA. To meet this need, reactive extrusion was employed to develop new materials based on PLA by grafting, compounding, and polymer blending. In the first part of this work, maleic anhydride (MA) was grafted onto PLA by reactive extrusion. Two structurally different peroxides were used to initiate grafting and results were reported on the basis of grafting, molecular weight, and thermal behavior. An inverse relationship between degree of grafting and molecular weight was established. It was also found that, regardless of peroxide type, there is an optimum peroxid-to-MA ratio of 0.5:2 that promotes maximum grafting, beyond which degradation reactions become predominant. Overall, it was found that the maleated copolymer (MAPLA) could be used as an interfacial modifier in PLA-based composites. Therefore, MAPLA was incorporated into PLA-talc composites in varying concentrations. The influence of the MAPLA addition on the mechanical and thermal behavior was investigated. When added in an optimum concentration, MAPLA improved the tensile strength and crystallization of the composite. Furthermore, microscopic observation confirmed the compatibilization effect of MAPLA in PLA-talc composites. Vinyltrimethoxysilane was free-radically grafted onto the backbone of PLA and subsequently moisture crosslinked. The effects of monomer, initiator, and catalyst concentration on the degree of crosslinking and the mechanical and thermal properties were investigated. The presence of a small amount of catalyst showed to be a major contributor to the crosslinking formation in the time frame investigated, shown by an increase in gel content and decrease in crystallinity. Furthermore, thermogravimetric analysis helped to establish a correlation between crosslinking density and thermal decomposition---providing conclusive evidence of improved thermal stability as a result of the crosslinking reaction. The mechanical properties indicated that the crosslinked PLA was developed without embrittlement or a reduction in tensile strength. In the final section of this work a blend comprising of PLA and PBAT was reactively compatibilized via an in situ transesterification reaction and blown films were produced. The compatibilized films demonstrated enhanced properties compared to those of the physical blends. The most significant improvements were observed in the composition where PBAT was the majority phase, PLA was the minor phase, and catalyst was added in low concentration. Morphological observation confirmed interaction between polymer phases by improved dispersion and significant reduction in domain size which inferred the formation of an interfacial copolymer.

Visualization analysis of tiger-striped flow mark generation phenomena in injection molding

NASA Astrophysics Data System (ADS)

Owada, Shigeru; Yokoi, Hidetoshi

2016-03-01

The generation mechanism of tiger-striped flow marks of polypropylene (PP)/rubber/talc blends in injection molding was investigated by dynamic visualization analysis in a glass-inserted mold. The analysis revealed that the behavior of the melt flow front correlates with the flow mark generation. The cloudy part in the tiger-striped flow marks corresponded to the low transcription rate area of the melt diverging near the cavity wall, while the glossy part corresponded to the high transcription rate area of the melt converging toward the cavity wall side. The melt temperature at the high transcription rate area was slightly lower than that at the low transcription rate area. These phenomena resulted due to the difference in the temperature of the melt front that was caused by the asymmetric fountain flow. These results suggest the followings; At the moment when the melt is broken near the one side of cavity wall due to piling the extensional strains up to a certain level, the melt spurts out near the broken side. It results in generating asymmetric fountain flow temporarily to relax the extensional front surface, which moves toward the opposite side to form the high transcription area.

Sodium hydroxide as a sclerosing agent in patients with neoplastic pleural effusion non-candidates for VATS: results of a minimally invasive protocol.

PubMed

Raices, Micaela; Czerwonko, Matías E; Dietrich, Agustin; Da Lozzo, Alejandro; Beveraggi, Enrique; Smith, David

2017-08-31

Symptomatic neoplastic pleural effusion (SNPE) is a significant cause of morbidity in patients with advanced neoplastic disease. These patients often present a deteriorated general condition which prevents them from undergoing pleurodesis with video-assisted thoracic surgery (VATS). We developed a minimally invasive therapeutic protocol specially designed for this population, achieved by combining chemical pleurodesis with placement of small-bore pleural catheters (PC), which resulted in early hospital discharge, low morbimortality and good therapeutic results. This study reports the safety and efficacy of administration of sodium hydroxide (NaOH) through PC in 60 patients diagnosed with SNPE who were admitted to Hospital Italiano de Buenos Aires between January 2012 and December 2015. Successful pleurodesis was achieved in 96% of procedures. Recurrence occurred in 25% of patients during follow-up, with recurrence occurring earlier than 30 days after pleurodesis in 8% of patients. There were no reports of major morbidity or associated mortality. In total, 44% of patients were discharged within 48 h of pleurodesis. Administration of NaOH through a small-bore PC represents an effective and safe method of pleurodesis in patients who are not candidates for talc pleurodesis by VATS.

Electromagnetic interference shielding effectiveness of polypropylene/conducting fiber composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Pyoung-Chan, E-mail: pclee@katech.re.kr; Kim, Bo-Ram; Jeoung, Sun Kyoung

Electromagnetic released from the automotive electronic parts is harmful to human body. Electromagnetic interference (EMT) shielding refers to the reflection and/or adsorption of electromagnetic radiation by a material, which thereby acts as a shield against the penetration of the radiation through the shield. Polypropylene (PP)/conductive micro fiber composites containing various fiber contents and fiber length were injection-molded. The effect of fiber content and length on electrical properties of the composites was studied by electrical resistivity and EMT shielding measurements. The through-plane electrical conductivity and dielectric permittivity were obtained by measuring dielectric properties. The EMT shielding effectiveness (SE) was investigated bymore » using S-parameter in the range of 100 ~ 1500 MHz. Reflection, absorption and multiple-reflection are the EMT attenuation mechanisms. From the measurement of S-Parameters, the absorption coefficient, reflection coefficient, and the shielding efficiency of the materials were calculated. The EMT SE of PP/conducing fiber composites is 40 dB over a wide frequency range up to 1.5 GHz, which is higher than that of PP/talc composite used automotive parts, viz. 0 dB.« less

An Application of X-Ray Fluorescence as Process Analytical Technology (PAT) to Monitor Particle Coating Processes.

PubMed

Nakano, Yoshio; Katakuse, Yoshimitsu; Azechi, Yasutaka

2018-06-01

An attempt to apply X-Ray Fluorescence (XRF) analysis to evaluate small particle coating process as a Process Analytical Technologies (PAT) was made. The XRF analysis was used to monitor coating level in small particle coating process with at-line manner. The small particle coating process usually consists of multiple coating processes. This study was conducted by a simple coating particles prepared by first coating of a model compound (DL-methionine) and second coating by talc on spherical microcrystalline cellulose cores. The particles with two layered coating are enough to demonstrate the small particle coating process. From the result by the small particle coating process, it was found that the XRF signal played different roles, resulting that XRF signals by first coating (layering) and second coating (mask coating) could demonstrate the extent with different mechanisms for the coating process. Furthermore, the particle coating of the different particle size has also been investigated to evaluate size effect of these coating processes. From these results, it was concluded that the XRF could be used as a PAT in monitoring particle coating processes and become powerful tool in pharmaceutical manufacturing.

The effectiveness of various Rhizobacteria carriers to improve the shelf life and the stability of Rhizobacteria as Bioherbicide

NASA Astrophysics Data System (ADS)

Rakian, T. C.; Karimuna, L.; Taufik, M.; Sutariati, G. A. K.; Muhidin; Fermin, U.

2018-02-01

Deleterius Rhizobacteria (DRB) has a potential to control of weed and act as a bioherbicide. Developing a method to weed control that environmentally sound friendly has been increasingly studied. Rhizobacteria can form colonies on weed rooting and synthesize the secondary metabolite compounds. The effectiveness of rhizobacteria as bioherbicide is determined by its survival to be stored for a long time. The objective of this study is to obtain the type of carrier which effectively maintains the life and stability of DRB. Therefore it is necessary to do in vivo and in-vitro research. This study consists of two stages of testing the effectiveness of the carrier in increasing the shelf life of rhizobacteria and testing the effectiveness stability as a bioherbicide on Ageratum conyzoides weed after storage for 20 weeks. Research was conducted in Agronomy Lab, Agriculture Faculty, Halu Oleo University Kendari, Since August to December 2016. Research found that the talc powder and chaff charcoal powder were effective as a carrier of rhizobacteria and able to maintain the viability of rhizobacteria Bacillus lentus A05 and Pseudomonas aeruginosa A08 for five months and also able to maintain the stability of rhizobacteria as bioherbicide.

Feasibility of a multi-component additive for efficient control of activated sludge filamentous bulking.

PubMed

Seka, A M; Van De Wiele, T; Verstraete, W

2001-08-01

Instantaneous improvement of the settling of bulking filamentous activated sludge can be achieved by the addition of a polymer or a large amount (up to 100% of the MLSS concentration) of talc powder to the sludge. Long-term improvement relies on repeated additions, as these additives have no adverse effects on the causative filaments. A multi-component additive was compared to the traditional additives in lab-scale activated sludge units using three highly filamentous sludges from different industrial treatment plants. The study demonstrated that the multi-component additive was superior to the traditional remedies. It was shown that, in the case of severe filamentous bulking, a single addition of the new additive immediately improved sludge settling and exerted a destructive effect on the causative filamentous bacteria. Thus, the latter additive also ensured a long-term sludge sedimentation improvement. The traditional additives exhibited an immediate and short-term effect. The novel additive also retarded sludge rising due to denitrification and it improved sludge dewaterability. The study revealed Nostocoido limicola II, with slightly hydrophobic cell wall, to be somewhat resistant to the quaternary ammonium salt present as biocide in the additive.

Removal of cyanobacterial blooms in Taihu Lake using local soils. I. Equilibrium and kinetic screening on the flocculation of Microcystis aeruginosa using commercially available clays and minerals.

PubMed

Pan, Gang; Zhang, Ming-Ming; Chen, Hao; Zou, Hua; Yan, Hai

2006-05-01

Algal removal abilities of 26 clays/minerals were classified into three categories according to the 8-h equilibrium removal efficiency (Q8h) and removal rate at a clay loading of 0.7 g/L. Type I clays (sepiolite, talc, ferric oxide, and kaolinite) had a Q8h > 90%, a t50 (time needed to remove 50% of the algae) < 15 min, and a t80 < 2.5 h. Type II clays (6 clays) had a Q8h 50-90%, a t50 < 2.5 h, and a t80 > 2.5 h. Type III clays (14 clays) with Q8h < 50%, t50 > 8 h and t80 > 14 h had no practical value in removal of algal blooms. When the clay loading was reduced to 0.2 g/L, Q8h for all the 25 materials decreased to below 60%, except for sepiolite whose Q8h remained about 97%. The high efficiency for sepiolite to flocculate M. aeruginosa cells in freshwaters was due to the mechanism of netting and bridging effect.

New milarite/osumilite-type phase formed during ancient glazing of an Egyptian scarab

NASA Astrophysics Data System (ADS)

Artioli, G.; Angelini, I.; Nestola, F.

2013-02-01

A scarab found in grave 25 of the Monte Prama necropolis, near Cabras, Oristano, Sardinia, is of special importance for the archaeological interpretation and dating of this important archaeological site. The object has been misinterpreted in the past as composed by bone: recent archaeometric analyses showed that it is a glazed steatite of Egyptian origin and that the altered surface contains interesting phases crystallized during the high-temperature interaction of the Mg-rich talc core with the alkali-rich glass used for glazing. A novel single crystal X-ray diffraction analysis of one of the phases indicates that it is a new compound having the milarite-osumilite structure type, with a peculiar composition close to (Na1.52K0.12□0.36)(Mg3)(Mg1.72Cu0.16Fe0.12)(Si11.4Al0.6)O30, not reported for naturally occurring minerals. The structural and crystal chemical features of the compound, together with the known high-temperature stability of the series, allow a complete interpretation of the glazing process and conditions, based on direct application of the glaze on the steatite core with subsequent treatment at temperatures above 1000 °C.

Stability of dry coated solid dosage forms.

PubMed

Kablitz, Caroline Désirée; Urbanetz, Nora Anne

2009-01-01

The dry coating process was evaluated in terms of storage stability investigating drug release and agglomeration tendency of the different coated oral dosage forms; hydroxypropyl methylcellulose acetate succinate (HPMCAS) was used with triethylcitrate (TEC) as plasticizer and acetylated monoglyceride (Myvacet) as wetting agent. Talc or colloidal silicon dioxide (Aerosil) was used as anti-tacking agents. In contrast to coating formulations consisting of HPMCAS and Myvacet all formulations containing TEC showed enteric resistance and no agglomeration tendency after preparation. After storage at 10% RH +/- 5% enteric resistance is increased slightly. This increase is more pronounced at 60% RH +/- 5%. The formulations without anti-tacking agents showed higher drug releases after 12 and 24 months due to the damage of the film's integrity during sample preparation caused by the high tackiness of the film. Tackiness is not affected by storing if samples are stored at low relative humidity. At high relative humidity tackiness increases upon storage especially for formulations without anti-tacking agents. The sieving results of the agglomeration measurements after storage can be confirmed by ring shear measurements performed immediately after preparation and approved to be a tool, which is able to predict the agglomeration during storage.

A case-control study of malignant and non-malignant respiratory disease among employees of a fiberglass manufacturing facility. II. Exposure assessment.

PubMed Central

Chiazze, L; Watkins, D K; Fryar, C; Kozono, J

1993-01-01

A case-control study of malignant and non-malignant respiratory disease among employees of the Owens-Corning Fiberglas Corporation's Newark, Ohio plant was undertaken. The aim was to determine the extent to which exposures to substances in the Newark plant environment, to non-workplace factors, or to a combination may play a part in the risk of mortality from respiratory disease among workers in this plant. A historical environmental reconstruction of the plant was undertaken to characterise the exposure profile for workers in this plant from its beginnings in 1934 to the end of 1987. The exposure profile provided estimates of cumulative exposure to respirable fibres, fine fibres, asbestos, talc, formaldehyde, silica, and asphalt fumes. Employment histories from Owens-Corning Fiberglas provided information on employment characteristics (duration of employment, year of hire, age at first hire) and an interview survey obtained information on demographic characteristics (birthdate, race, education, marital state, parent's ethnic background, and place of birth), lifetime residence, occupational and smoking histories, hobbies, and personal and family medical history. Matched, unadjusted odds ratios (ORs) were used to assess the association between lung cancer or non-malignant respiratory disease and the cumulative exposure history, demographic characteristics, and employment variables. Only the smoking variables and employment characteristics (year of hire and age at first hire) were statistically significant for lung cancer. For non-malignant respiratory disease, only the smoking variables were statistically significant in the univariate analysis. Of the variables entered into a conditional logistic regression model for lung cancer, only smoking (smoked for six months or more v never smoked: OR = 26.17, 95% confidence interval (95% CI) 3.316-206.5) and age at first hire (35 and over v less than 35: OR = 0.244, 95% CI 0.083-0.717) were statistically significant. There were, however, increased ORs for year of employment (first hired before 1945 v first hire after 1945: OR = 1.944, 95% CI 0.850-4.445), talc (cumulative exposure >1000 fibres/ml days v never exposed: OR = 1.355, 95% CI 0.407-5.515), and asphalt fumes (cumulative exposure >0.01 mg/m(3) days v never exposed: OR 1.131, 95% CI 0.468-2.730). For non-malignant respiratory disease, only the smoking variable was significant in the conditional logistic regression analysis (OR = 2.637, 95% CI 1.146-6.069). There were raised ORs for the higher cumulative exposure categories for respirable fibres, asbestos, silica, and asphalt fumes. For both silica and asphalt fumes, ORs were more than double the reference groups for all exposure categories. A limited number of subjects were exposed to fine fibres. The scarcity of cases and controls limits the extent to which analyses for fine fibre may be carried out. Within those limitations, among those who had worked with fine fibre, the unadjusted, unmatched OR for lung cancer was (1.0 (95% CI 0.229-4.373) and for non-malignant respiratory disease, the OR was 1.5 (95% CI 0.336-6.702). The unadjusted OR for lung cancer for exposure to fine fibre was consistent with that for all respirable fibre and does not suggest an association. For non-malignant respiratory disease, the unadjusted OR for fine fibre was opposite in direction from that for all respirable fibres. Within the limitations of the available data on fibre, there is o suggestion that exposure to fine fibre has resulted in an increase in risk of lung cancer. The increased OR for non-malignant respiratory disease is inconclusive. The results of this population, in this place and time, neither respirable fibres nor any of the substances investigated as part of the plant environment are statistically significant factors for lung cancer risk although there are increased ORs for exposure to talc and asphalt fumes. Smoking is the most important factors in risk for lung cancer in this population. The situation is less clear for non-malignant respiratory disease. Unlike lung cancer, non-malignant respiratory represents a constellation of outcomes and not a single well defined end point. Although smoking was the only statistically significant factor for non-malignant respiratory disease in this analysis, the ORs for respirable fibres, asbestos, silica, and asphalt fumes were greater than unity for the highest exposure categories. Although the raised ORs for these substances may represent the results of a random process, they may be suggestive of an increased risk and require further investigation. PMID:8398858

P-T evolution of slivers of garnet-bearing micaschist in the sole of the Western Vardar Ophiolite Unit at Brezovica, Kosovo

NASA Astrophysics Data System (ADS)

Massonne, Hans-Joachim; Koller, Friedrich; Onuzi, Kujtim

2016-04-01

Rocks of the metamorphic sole of ophiolite complexes are regarded as an important factor to understand the process of obduction of former oceanic lithosphere on top of continental crust. The metamorphic evolution of these rocks can give, for instance, hints at the thickness of the obducted oceanic lithosphere. We have started to study the sole of the Western Vardar Ophiolitic Unit at the municipality of Bresovica, Kosovo. This unit is regarded as part of the former Vardar Ocean, a branch of the Neotethys, which was obducted onto the margin of the Adriatic microplate in Jurassic times. The sole in our study area, below strongly serpentinized ultramafic rocks, is characterized by a melange of various rock types, which are of medium metamorphic grade only in the vicinity of the ultramafic rocks. Our field work resulted in the recognition of several slivers of garnet-bearing micaschist among these medium-grade rocks which are dominated by amphibolite. In such a medium-grade rock from Bresovica the mineral assemblage talc + phengite was reported (Abraham and Schreyer, 1976, J. Petrol. 17, 421-439), which turned out by experiments in a piston-cylinder apparatus to be a high-pressure (HP: > 10 kbar) assemblage (Massonne and Schreyer, 1989, Eur. J. Mineral. 1, 391-410). We studied a garnet-bearing micaschist in detail. Elemental mapping and spot analyses of garnet obtained with an electron microprobe yielded core compositions of Alm0.695Gross(+Andr)0.11Pyr0.185Spes0.01. The composition of the garnet rim is Alm0.71Gross(+Andr)0.065Pyr0.21Spes0.015. On the basis of the bulk-rock composition of the micaschist, a P-T pseudosection was constructed with PERPLEX in the system K-Na-Ca-Mg-Mn-Fe-Al-Si-Ti-O-H. This pseudosection was contoured by isopleths for various parameters among them were the molar fractions of garnet components. According to such isopleths and the compositional variation of garnet, a more or less isobaric heating is likely. This heating to 650 °C has occurred at a pressure of 11.5 kbar, which is compatible with the aforementioned talc + phengite assemblage. We think that the recognized HP metamorphism of the studied micaschist was caused by the load of the obducting oceanic lithosphere, which must have been as thick as 35 km. Heating of the overridden rocks during this obduction process resulted in the release of H2O, which hydrated the mantle rocks at the base of the obducting oceanic lithosphere. An alternative model, which assigned the location of the hydration to the mantle wedge overlying a subduction zone, was abandoned also because of the existence of higher levels of oceanic crust, such as pillow lavas, in the preserved oceanic lithosphere close to the Brezovica region.

Komatiites and nickel sulphide orebodies of the Black Swan area, Yilgarn Craton, Western Australia. 1. Petrology and volcanology of host rocks

NASA Astrophysics Data System (ADS)

Hill, R. E. T.; Barnes, S. J.; Dowling, S. E.; Thordarson, T.

2004-11-01

The Black Swan Succession is a bimodal association of dacitic and komatiitic volcanic rocks located about 50 km NNE of Kalgoorlie, within the 2.7-Ga Eastern Goldfields greenstone province of the Yilgarn Craton. The komatiite stratigraphy comprises a steep dipping, east facing package about 700 m in maximum thickness and about 2.5 km in strike length (Fig. 1), which hosts a number of economically exploitable Ni sulphide orebodies including the Silver Swan massive ore shoot (approximately half a million tonnes at about 10.5% Ni). The sequence can be subdivided into a Lower Felsic Unit, comprising coherent and autobrecciated facies of multiple dacite lava flows; an upper Eastern and lower Western Ultramafic Unit, each showing marked lateral facies variation, and an Upper Felsic Unit coeval with the Eastern Ultramafic Unit. The komatiite sequence has been metamorphosed at sub-greenschist facies in the presence of high proportions of CO2-rich fluid, giving rise to pervasive talc carbonate and talc carbonate quartz assemblages, with extensive preservation of pseudomorphed igneous textures. Cores of lizardite serpentinite are present in the thickest parts of the ultramafic succession. The degree of penetrative deformation is generally very low, and original stratigraphic relationships are largely intact in much of the sequence. The Eastern Ultramafic Unit and Western Ultramafic Unit are interpreted as components of a single large komatiite flow field, representing overlapping stages in the emplacement of a series of distributory lava pathways and flanking sheet flows. The Western Ultramafic Unit which hosts the bulk of the high-grade massive and disseminated ores is a sequence dominated by coarse-grained olivine cumulates, 2 km wide and up to 500 m thick, with major magma pathways represented by thick, homogenous olivine mesocumulate piles at its northern and southern ends: respectively 400 and 200 m thick. The sequence between the two major pathways consists of olivine orthocumulates (oOC) with minor spinifex-textured intervals. The Unit is capped by a persistent spinifex-textured crust less than 1 m thick, and is locally vesicular. The Eastern Ultramafic Unit contains the Black Swan Cumulate Zone, a 500-m thick sequence of very coarse-grained hopper-textured, locally vesicular oOC containing disseminated sulphides in its lower 200 m. The zone is flanked to the north and south by complexly interdigitated sequence of highly irregular, spinifex-capped, olivine cumulate-rich flow lobes between 1 and 100 m thick, and dacitic lavas and tuffs. The complexity of the 3-D spatial relationship of these units suggests a combination of simultaneous eruption of dacite and komatiite, combined with thermal or thermomechanical erosion. The Eastern and Western Units are interpreted as the result of more or less continuous prolonged eruption of olivine charged komatiite lava, which developed localised thermo-mechanical erosion channels in the dacitic substrate. Komatiite and dacite eruption was synchronous, giving rise to complex interdigitation and extensive contamination and hybridisation.

Time-Resolved Remote-Raman Spectroscopic study of Minerals at High Temperature and under Supercritical CO2 Relevant to Venus Exploration

NASA Astrophysics Data System (ADS)

Sharma, S. K.; Misra, A. K.; Clegg, S. M.; Barefield, J. E.; Wiens, R. C.; Acosta, T.

2009-12-01

We have used a remote time-resolved (TR) telescopic Raman system equipped with 532 nm pulsed laser excitation and a gated intensified CCD (ICCD) detector for measuring Raman spectra of a number of minerals under two sets of conditions. The first set of experiments involved probing samples as a function of temperature ranging from 300 to 973 K at 1 atm. These experiments involve a 5x beam expander to focus the 532 nm (30 mJ/pulse 20 Hz) laser beams onto the sample at 9 m from the remote Raman system. The second set of experiments involved placing the samples in a high pressure vessel with a sapphire window containing supercritical CO2 at pressures up to 93 atm and 423 K. At high temperatures and ambient pressure, the remote Raman measurements were made with samples at 9 meter distance inside a high temperature furnace by gating the ICCD detector with 2 micro-s gate to minimize interference from blackbody emission from mineral surfaces at high temperature as well as interference from ambient light. A comparison of Raman spectra of gypsum (CaSO4.2H2O), dolomite (CaMg(CO3)2), and olivine (Mg2Fe2-xSiO4), as a function of temperature shows that the Raman lines remains sharp and well defined even in the high temperature spectra. In the pressure vessel, Cr3+ fluorescence from sapphire window interfere with the Raman spectra of hydrous minerals in the high-frequency region (2500-4500 cm-1). With time-resolved Raman measurements the interference of the fluorescence in the Raman spectra on minerals was minimized by gating ICCD to <100 ns. The Fermi resonance doublet of CO2 molecules consisting of Raman lines at 1285 (2ν2) and 1388 (ν1) cm-1 does not interfere with the major Raman fingerprints of silicates, carbonate, sulfates minerals. With suitable time delay of the ICCD detector, the Raman bands from supercritical CO2 atmosphere can be minimized providing pure Raman spectra of the mineral targets. We will present remote Raman data on silicates (olivine, pyroxene, quartz, feldspars and talc), dolomite, gypsum, hydrous iron sulfate and barite under supercritical CO2 environment. With TR remote Raman system using 532 nm (15 mJ/pulse, 20Hz) laser excitation, a large varieties of minerals could be easily identified from their respective Raman fingerprints typically in 1s. Minerals with low Raman cross section (e.g., feldspars, pyroxene, olivine, talc, etc) can be detected and quantified from their respective Raman spectra in 10 to 30 s. These results show that time-resolve remote Raman system is capable of making spectral measurements at several hundred to thousand target points on Venus surface within limited (a few hours) expected lifetime of a lander because of extreme temperature and pressure conditions.

Implications of Microstructural Studies of the SAFOD Gouge for the Strength and Deformation Mechanisms in the Creeping Segment of the San Andreas Fault

NASA Astrophysics Data System (ADS)

Hadizadeh, J.; Gratier, J. L.; Mittempergher, S.; Renard, F.; Richard, J.; di Toro, G.; Babaie, H. A.

2010-12-01

The San Andreas Fault zone (SAF) in the vicinity of the San Andreas Fault Observatory at Depth (SAFOD)in central California is characterized by an average 21 mm/year aseismic creep and strain release through repeating M<3 earthquakes. Seismic inversion studies indicate that the ruptures occur on clusters of stationary patches making up 1% or less of the total fault surface area. The existence of these so-called asperity patches, although not critical in determining the fault strength, suggests interaction of different deformation mechanisms. What are the deformation mechanisms, and how do the mechanisms couple and factor into the current strength models for the SAF? The SAFOD provides core samples and geophysical data including cores from two shear zones where the main borehole casing is deforming. The studies so far show a weak fault zone with about 200m of low-permeability damage zone without anomalous temperature or high fluid pressure (Zoback et al. EOS 2010). To answer the above questions, we studied core samples and thin sections ranging in measured depths (MD) from 3059m to 3991m including gouge from borehole casing deformation zones. The methods of study included high resolution scanning and transmission electron microscopy, cathodoluminescence imaging, X-ray fluorescence mapping, and energy dispersive X-ray spectroscopy. The microstructural and analytical data suggest that deformation is by a coupling of cataclastic flow and pressure solution accompanied by widespread alteration of feldspar to clay minerals and other neomineralizations. The clay contents of the gouge and streaks of serpentinite are not uniformly distributed, but weakness of the creeping segment is likely to be due to intrinsically low frictional strength of the fault material. This conclusion, which is based on the overall ratio of clay/non-clay constituents and the presence of talc in the actively deforming zones, is consistent with the 0.3-0.45 coefficient of friction for the drill cuttings tested by others. We also considered weakening by diffusion-accommodated grain boundary sliding. There are two main trends in the microstructural data that provide a basis for explaining the creep rate and seismic activity: 1. Clay content of the gouge including serpentinite and talc increases toward the 1-3m wide borehole casing deformation zones, which are expected to be deforming at above the average creep rate 2. Evidence of pressure solution creep and fracture sealing is more abundant in the siltstone cataclasites than in the shale. Such rocks could act as rigid inclusions that are repeatedly loaded to seismic failure by creep of the surrounding clay gouge. Regular cycles of fracture and restrengthening by fracture sealing in and around the inclusions are thus expected. The inclusions may be viewed as asperity patches (or cluster of patches) that predominantly deform by pressure solution at below the average creep rate.

Radioactivity in books printed in Japan: its source and relation to the year of issue.

PubMed

Kobashi, A

1996-06-01

The radioactivities of the naturally occurring radionuclides (226Ra, 228Ra, 228Th and 40K) and a fallout nuclide (137Cs) in books produced in Japan in the 20th century were measured by gamma-ray spectrometry to obtain information on radiation emitted from books. The respective concentration ranges of 226Ra, 228Ra, 228Th, 40K, and 137Cs were 0.2-6.4, 0.4-11.2, 0.3-11.3, 1-112, and 0-3 Bq kg-1. X-ray diffraction spectra of the papers used in book printing showed that pyrophyllite, talc, kaolinite, and calcium carbonate were contained as fillers. A comparison of the radioactivity contents of the pulp and filler indicated that most of 226Ra, 228Ra, and 228Th in the books was present in the filler whereas 137Cs was in the pulp. The pattern of the concentration of each nuclide vs. the year of issue of the book was investigated. Patterns for the naturally occurring radionuclides were similar and were explained by the kinds of filler used. The pattern for 137Cs differed from the patterns of the naturally occurring radionuclides, having a marked peak in the mid-1960s.

Clay-catalyzed reactions of coagulant polymers during water chlorination

USGS Publications Warehouse

Lee, J.-F.; Liao, P.-M.; Lee, C.-K.; Chao, H.-P.; Peng, C.-L.; Chiou, C.T.

2004-01-01

The influence of suspended clay/solid particles on organic-coagulant reactions during water chlorination was investigated by analyses of total product formation potential (TPFP) and disinfection by-product (DBP) distribution as a function of exchanged clay cation, coagulant organic polymer, and reaction time. Montmorillonite clays appeared to act as a catalytic center where the reaction between adsorbed polymer and disinfectant (chlorine) was mediated closely by the exchanged clay cation. The transition-metal cations in clays catalyzed more effectively than other cations the reactions between a coagulant polymer and chlorine, forming a large number of volatile DBPs. The relative catalytic effects of clays/solids followed the order Ti-Mont > Fe-Mont > Cu-Mont > Mn-Mont > Ca-Mont > Na-Mont > quartz > talc. The effects of coagulant polymers on TPFP follow the order nonionic polymer > anionic polymer > cationic polymer. The catalytic role of the clay cation was further confirmed by the observed inhibition in DBP formation when strong chelating agents (o-phenanthroline and ethylenediamine) were added to the clay suspension. Moreover, in the presence of clays, total DBPs increased appreciably when either the reaction time or the amount of the added clay or coagulant polymer increased. For volatile DBPs, the formation of halogenated methanes was usually time-dependent, with chloroform and dichloromethane showing the greatest dependence. ?? 2003 Elsevier Inc. All rights reserved.

Investigating critical effects of variegated lubricants, glidants and hydrophilic additives on lag time of press coated ethylcellulose tablets.

PubMed

Patadia, Riddhish; Vora, Chintan; Mittal, Karan; Mashru, Rajashree

2016-01-01

The research envisaged focuses on vital impacts of variegated lubricants, glidants and hydrophilic additives on lag time of press coated ethylcellulose (EC) tablets using prednisone as a model drug. Several lubricants and glidants such as magnesium stearate, colloidal SiO2, sodium stearyl fumarate, talc, stearic acid, polyethylene glycol (6000) and glyceryl behenate were investigated to understand their effects on lag time by changing their concentrations in outer coat. Further, the effects of hydrophilic additives on lag time were examined for hydroxypropylmethylcellulose (E5), hydroxypropylcellulose (EF and SSL), povidone (K30), copovidone, polyethylene glycol (4000), lactose and mannitol. In vitro drug release testing revealed that each selected lubricant/glidant, if present even at concentration of 0.25% w/w, significantly reduced the lag time of press coated tablets. Specifically, colloidal SiO2 and/or magnesium stearate were detrimental while other lubricants/glidants were relatively less injurious. Among hydrophilic additives, freely water soluble fillers had utmost influence in lag time, whereas, comparatively less impact was observed with polymeric binders. Concisely, glidant and lubricant should be chosen to have minimal impact on lag time and further judicious selection of hydrophilic additives should be exercised for modulating lag time of pulsatile release formulations.

Origin and the mechanical properties of asbestos

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Hanley, D.S.

1986-01-01

Dual networks and chemographic analysis are used to investigate the stability of lizardite and chrysotile in the simplest multisystem that describes serpentinization. Phase diagrams for Mg serpentinites described by MgO-SiO/sub 2/-H/sub 2/O are constructed for systems of five, six and seven phases using dual networks. The seven-phase system brucite, forsterite, lizardite, chrysotile, antigorite, enstatite, and talc describes the serpentinization of Mg peridotites. The chrysotile asbestos deposits of southeastern Quebec occur in serpentinized peridotites of Ordovician ophiolites. The asbestos is localized in veins within blocks of partly serpentinized peridotite bounded by zones containing schistose serpentinite and granitic masses. A simple, rapidmore » microscopic test was designed to obtain semi-quantitative measurements of the bending strength of acicular or fibrous crystals. The instrument was tested on samples of asbestiform tremolite from Baltimore, Maryland, and non-asbestiform tremolite from the Warren Head mine in New Hampshire. The samples ranged in size from 0.3 to 0.8 mm in length and 0.9 to 15 ..mu..m in diameter. The asbestiform tremolite was stronger than the non-asbestiform tremolite at every diameter, with an order of magnitude higher strength at small diameters. This indicates that asbestiform tremolite behaves as a whisker, whereas non-asbestiform tremolite does not.« less

The Preparation of Capsaicin-Chitosan Microspheres (CCMS) Enteric Coated Tablets

PubMed Central

Chen, Jian; Huang, Gui-Dong; Tan, Si-Rong; Guo, Jiao; Su, Zheng-Quan

2013-01-01

This study aimed to research the preparation and content determination of capsaicin-chitosan microspheres (CCMS) enteric coated tablets. The core tablets were prepared with the method of wet granulation. Nine formulae were designed to determine the optimal formula of the core tablet. Eudragit L100 was used to prepare the CCMS enteric-coated tablets. The effect of enteric coated formulation variables such as content of talc (10%, 25% and 40%), plasticisers (TEC and DBS), dosage of plasticiser (10%, 20% and 30%) and coating weight (2%, 3% and 5%) were evaluated for drug release characteristics. The in vitro release was studied using 0.1 N HCl and pH 6.8 phosphate buffer. Enteric coated tablets without ruptures or swelling behaviour over 2 h in 0.1 N HCl indicated that these tablets showed acid resistance. The accumulated release rate in phosphate buffer (pH 6.8) revealed that the prepared tablets were able to sustain drug release into the intestine and a first-order release was obtained for capsaicin. This research is the first report of the preparation and content determination of CCMS enteric coated tablets. The sustained release behavior of enteric coated formulations in pH 6.8 phosphate buffer demonstrated that it would be a potential drug delivery platform for sustained delivery of gastric irritant drugs. PMID:24351818

Geology of the Spruce Pine District, Avery, Mitchell, and Yancy Counties, North Carolina

USGS Publications Warehouse

Brobst, Donald Albert

1962-01-01

The Spruce Pine pegmatite district, a northeastward-trending belt 25 miles long and 10 miles wide, lies in parts of Avery, Mitchell, and Yancey Counties in the Blue Ridge Province of western North Carolina. The most abundant rocks in the district are interlayered mica and amphibole gneisses and schists, all of which are believed to be of Precambrian age. These rocks are cut by small bodies of dunite and associated rocks of Precambrian (?) age, large bodies of alaskite and associated pegmatite of early Paleozoic age, and basaltic and diabasic dikes and sills of Triassic (?) age. The rocks of the district have been weathered to saprolite that is locally 50 feet thick. The major structure in the area is a southwestward-plunging asymmetrical synclinorium that has its steeper limb on the northwest side. Feldspar, muscovite as sheet and scrap (ground) mica, and kaolin from the alaskite and associated pegmatite account for over 90 percent of the total mineral production of the district. Amounts of other pegmatite minerals, including quartz, beryl, columbite-tantalite, rare-earth and uranium minerals are an extremely small part of the mineral resources. Actual or potential products from other rocks are olivine, vermiculite, asbestos, talc, chromium and nickel, soapstone, mica schist, garnet, kyanite, dolomite marble, and construction materials.

Conventional versus pigtail chest tube-are they similar for treatment of malignant pleural effusions?

PubMed

Mendes, Maria Aurora; China Pereira, Nuno; Ribeiro, Carla; Vanzeller, Manuela; Shiang, Teresa; Gaio, Rita; Campainha, Sérgio

2018-08-01

The optimal chest tube type and size for drainage and chemical pleurodesis of malignant pleural effusions remains controversial. This retrospective study was conducted to compare the efficacy of conventional versus pigtail chest tube in the treatment of malignant pleural effusions. Patients submitted to chest tube drainage and slurry talc pleurodesis due to malignant pleural effusion in our pulmonology ward from 2012 to 2016 were eligible. According to the type of chest tube, they were divided into two groups: group I-conventional chest tube and group II-pigtail chest tube. Number of deaths, recurrence of malignant pleural effusion, and timelines associated with the procedures were reviewed and compared between groups. Out of the 61 included patients, 46 (75.4%) were included in group I and 15 (24.6%) in group II. Only one patient had pigtail chest tube obstruction, with posterior insertion of conventional chest tube. Death during hospital stay and up to 3 months, recurrence at 4 weeks, total duration of hospital stay, time from chest tube insertion to pleurodesis, and time from chest tube insertion to removal were not significantly different between the two groups (all p > 0.05). These findings suggest that pigtail chest tube can be an alternative on palliation, with no compromise in pleurodesis performance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semin Chong; Kyung Soo Lee; Myung Jin Chung

Pneumoconiosis may be classified as either fibrotic or nonfibrotic, according to the presence or absence of fibrosis. Silicosis, coal worker pneumoconiosis, asbestosis, berylliosis, and talcosis are examples of fibrotic pneumoconiosis. Siderosis, stannosis, and baritosis are nonfibrotic forms of pneumoconiosis that result from inhalation of iron oxide, tin oxide, and barium sulfate particles, respectively. In an individual who has a history of exposure to silica or coal dust, a finding of nodular or reticulonodular lesions at chest radiography or small nodules with a perilymphatic distribution at thin-section computed tomography (CT), with or without eggshell calcifications, is suggestive of silicosis or coalmore » worker pneumoconiosis. Magnetic resonance imaging is helpful for distinguishing between progressive massive fibrosis and lung cancer. CT and histopathologic findings in asbestosis are similar to those in idiopathic pulmonary fibrosis, but the presence of asbestos bodies in histopathologic specimens is specific for the diagnosis of asbestosis. Giant cell interstitial pneumonia due to exposure to hard metals is classified as a fibrotic form of pneumoconiosis and appears on CT images as mixed ground-glass opacities and reticulation. Berylliosis simulates pulmonary sarcoidosis on CT images. CT findings in talcosis include small centrilobular and subpleural nodules or heterogeneous conglomerate masses that contain foci of high attenuation indicating talc deposition. Siderosis is nonfibrotic and is indicated by a CT finding of poorly defined centrilobular nodules or ground-glass opacities.« less

Heavy metals concentration and availability of different soils in Sabzevar area, NE of Iran

NASA Astrophysics Data System (ADS)

Mazhari, Seyed Ali; Sharifiyan Attar, Reza; Haghighi, Faezeh

2017-10-01

Soils developed in the Sabzevar ophiolitic area originate from different bedrocks. All samples display similar physico-chemical properties, but heavy metal concentrations vary extremely in different soil samples. Serpentine soils have the highest total concentration of Cr, Ni and Co; while soils derived from mafic rocks (olivine basalts and hornblende gabbros) show the highest Cu (85.29-109.11 ppm) and Zn (46.88-86.60 ppm). The DTPA-extraction of soil samples indicates that the order of metal bioavailability was Cr3% of total Cr; >12% of total Co and >17% of total Zn). Oxide minerals (such as chromite and magnetite) in Sabzevar soils play as resistant minerals and impede the heavy metal availability; while forsterite, pyroxene, serpentine and talc are more labile and show higher DTPA-extractable of heavy metals.

Improved ceramic heat exchanger materials

NASA Technical Reports Server (NTRS)

Rauch, H. W.

1980-01-01

The development and evaluation of materials for potential application as heat exchanger structures in automotive gas turbine engines is discussed. Test specimens in the form of small monolithic bars were evaluated for thermal expansion and dimensional stability before and after exposure to sea salt and sulfuric acid, followed by short and long term cycling at temperatures up to 1200 C. The material finally selected, GE-7808, consists of the oxides, ZrO2-MgO-Al2O3-S1O2, and is described generically as ZrMAS. The original version was based on a commercially available cordierite (MAS) frit. However, a clay/talc mixture was demonstrated to be a satisfactory very low cost source of the cordierite (MAS) phase. Several full size honeycomb regenerator cores, about 10.2 cm thick and 55 cm diameter were fabricated from both the frit and mineral versions of GE-7808. The honeycomb cells in these cores had rectangular dimensions of about 0.5 mm x 2.5 mm and a wall thickness of approximately 0.2 mm. The test data show that GE-7808 is significantly more stable at 1100 C in the presence of sodium than the aluminosilicate reference materials. In addition, thermal exposure up to 1100 C, with and without sodium present, results in essentially no change in thermal expansion of GE-7808.

The detection of drugs of abuse in fingerprints using Raman spectroscopy I: latent fingerprints

NASA Astrophysics Data System (ADS)

Day, Joanna S.; Edwards, Howell G. M.; Dobrowski, Steven A.; Voice, Alison M.

2004-02-01

This paper describes the application of Raman spectroscopy to the detection of exogenous substances in latent fingerprints. The scenario considered was that of an individual handling a substance and subsequently depositing a contaminated fingerprint. Five drugs of abuse (codeine phosphate, cocaine hydrochloride, amphetamine sulphate, barbital and nitrazepam) and five non-controlled substances of similar appearance, which may be used in the adulteration of drugs of abuse (caffeine, aspirin, paracetamol, starch and talc), were studied in both sweat-rich and sebum-rich latent fingerprints. The substances studied could be clearly distinguished using their Raman spectra and were all successfully detected in latent fingerprints. Photobleaching was necessary to reduce the fluorescence background in the spectra of some substances. Raman spectra obtained from the substances in sweat-rich latent fingerprints were of a similar quality to spectra that obtained from the substances under normal sampling conditions. Interfering Raman bands arising from latent fingerprint material were present in the spectra obtained from the substances in sebum-rich fingerprints. These bands did not prevent identification of the substances and could be successfully removed by spectral subtraction. The most difficult aspect of the detection of these substances in latent fingerprints was visually locating the substance in the fingerprint in order to obtain a Raman spectrum.

Administration of Intravenous Inf liximab for Prevention of Peritoneal Adhesions Formation in Rats.

PubMed

Nikeghbalian, Saman; Vafaei, Homeira; Moradian, Farid; Kazemi, Kourosh; Tanideh, Nader; Shayan, Leila; Nikeghbalian, Zahra

2015-07-01

To investigate the effects of intravenous infliximab in preventing the formation of peritoneal adhesions in an animal model of rat. This was an experimental study being performed in animal laboratory of Shiraz University of Medical Sciences during 2012. Sixty albino rats were randomly assigned in to three groups by Random Design Method. The first group received single infliximab injection (n=20), the second one received double infliximab injection (n=20) and the third received nothing (n=20), after receiving intra-peritoneal injection of talc for induction of peritoneal adhesions. All the animals were sacrificed after 6 weeks and the peritoneal adhesions were evaluated according to Nair classification. We observed that the mean adhesion grade was lower in those who received double dose of infliximib when compared to single dose and controls. However the difference did not reach a significant value (p=0.178). The grade of peritoneal adhesion was also comparable between the three study groups (p=0.103). The mean number of 1st WBC count was also comparable between three study groups (p=0.382). We observed that 2nd WBC count was also comparable between two study groups (p=0.317). Administration of intravenous infliximab after intraabdominal surgicalprocedures would not prevent the formation of peritoneal adhesions in animal model of albino rat.

Compression parameters of hexagonal boron nitride on direct compression mixture of microcrystalline cellulose and modified starch.

PubMed

Halaçoğlu, Mekin Doğa; Uğurlu, Timuçin

2015-01-01

The objective of this study was to investigate the effects of conventional lubricants including a new candidate lubricant "hexagonal boron nitride (HBN)" on direct compression powders. Lubricants such as magnesium stearate (MGST), glyceryl behenate, stearic acid, talc and polyethylene glycol6000 were studied and tablets were manufactured on a single station instrumented tablet press. This study comprised the continuation of our previous one, so mixture of microcrystalline cellulose and modified starch was used as a master formula to evaluate effects of lubricants on pharmaceutical excipients that undergo complete plastic deformation without any fragmentation under compression pressure. Bulk and tapped densities, and Carr's index parameters were calculated for powders. Tensile strength, cohesion index, lower punch ejection force and lubricant effectiveness values were investigated for tablets. The deformation mechanisms of tablets were studied during compression from the Heckel plots with or without lubricant. MGST was found to be the most effective lubricant and HBN was found very close to it. HBN did not show a significant negative effect on the crushing strength and disintegration time of the tablets when we compared with MGST. Based on the Heckel plots at the level of 1%, formulation prepared with HBN showed the most pronounced plastic character.

Cosmetics use and age at menopause: Is there a connection?

PubMed Central

Chow, Erika; Mahalingaiah, Shruthi

2016-01-01

Short Narrative Abstract Cosmetics contain a vast number of chemicals, most of which are not under the regulatory purview of the Food and Drug Administration. Only a few of these chemicals have been evaluated for potential deleterious health impact – parabens, phthalates, polycyclic aromatic hydrocarbons, and siloxanes. A review of the ingredients in the best-selling and top rated products of the top beauty brands in the world, as well as a review of highlighted chemicals by non-profit environmental organizations reveal 11 chemicals and chemical families of concern: butylated hydroxyanisole/butylated hydroxytoluene, coal tar dyes, diethanolamine, formaldehyde releasing preservatives, parabens, phthalates, 1,4 dioxane, polycyclic aromatic hydrocarbons, siloxanes, talc/asbestos, and triclosan. Age at menopause can be affected by a variety of mechanisms, including endocrine disruption, failure of DNA repair, oxidative stress, shortened telomere length, and ovarian toxicity. There is a lack of available studies to make a conclusion regarding cosmetics use and age at menopause. What little data there is suggests future studies are warranted. Women with chronic and consistent use of cosmetics across their lifespan may be a population of concern. More research is required to better elucidate the relationship and time windows of vulnerability and the effects of mixtures and combinations of products on ovarian health. PMID:27545020

Mantle wedge infiltrated with saline fluids from dehydration and decarbonation of subducting slab

PubMed Central

Kawamoto, Tatsuhiko; Yoshikawa, Masako; Kumagai, Yoshitaka; Mirabueno, Ma. Hannah T.; Okuno, Mitsuru; Kobayashi, Tetsuo

2013-01-01

Slab-derived fluids play an important role in heat and material transfer in subduction zones. Dehydration and decarbonation reactions of minerals in the subducting slab have been investigated using phase equilibria and modeling of fluid flow. Nevertheless, direct observations of the fluid chemistry and pressure–temperature conditions of fluids are few. This report describes CO2-bearing saline fluid inclusions in spinel-harzburgite xenoliths collected from the 1991 Pinatubo pumice deposits. The fluid inclusions are filled with saline solutions with 5.1 ± 1.0% (wt) NaCl-equivalent magnesite crystals, CO2-bearing vapor bubbles, and a talc and/or chrysotile layer on the walls. The xenoliths contain tremolite amphibole, which is stable in temperatures lower than 830 °C at the uppermost mantle. The Pinatubo volcano is located at the volcanic front of the Luzon arc associated with subduction of warm oceanic plate. The present observation suggests hydration of forearc mantle and the uppermost mantle by slab-derived CO2-bearing saline fluids. Dehydration and decarbonation take place, and seawater-like saline fluids migrate from the subducting slab to the mantle wedge. The presence of saline fluids is important because they can dissolve more metals than pure H2O and affect the chemical evolution of the mantle wedge. PMID:23716664

Effects of some lubricants and evaluation of compression parameters on directly compressible powders.

PubMed

Uğurlu, Timuçin; Halaçoğlu, Mekin Doğa

2014-05-01

The objective of this study was to investigate the effects of conventional lubricants including a new candidate lubricant "Hexagonal boron nitride (HBN)" on direct compression powders. Lubricants such as magnesium stearate, glyceryl behenate, stearic acid, talc and polyethylene glycol6000 were studied in this article. Tablets were manufactured on an instrumented tablet press with various lubricant concentrations. Bulk and tapped densities, and Carr's index parameters were calculated for powders. Tensile strength, cohesion index, lower punch ejection force and lubricant effectiveness values were investigated for tablets. The deformation mechanisms of tablets were studied during compression from the Heckel plots with or without lubricants. Powders formulated with MGST and HBN showed better flow properties based on Carr's index. MGST was found to be the most effective lubricant based on lubricant effectiveness for tablets. HBN was found very close to MGST with the same concentrations. Other lubricants showed less effectiveness than that of MGST and HBN. It is observed that an increase in the concentration of HBN leads to decreased tensile strength and cohesion index values because of its surface-covering property. Despite covering property, HBN had no significant effect on disintegration time. Based on the Heckel plots at the level of 1%, HBN showed the most pronounced plastic character.

Production of Ultrafine, High-purity Ceramic Powders Using the US Bureau of Mines Developed Turbomill

NASA Technical Reports Server (NTRS)

Hoyer, Jesse L.

1993-01-01

Turbomilling, an innovative grinding technology developed by the U.S. Bureau of Mines in the early 1960's for delaminating filler-grade kaolinitic clays, has been expanded into the areas of particle size reduction, material mixing, and process reaction kinetics. The turbomill, originally called an attrition grinder, has been used for particle size reduction of many minerals, including natural and synthetic mica, pyrophyllite, talc, and marble. In recent years, an all-polymer version of the turbomill has been used to produce ultrafine, high-purity, advanced ceramic powders such as SiC, Si3N4, TiB2, and ZrO2. In addition to particle size reduction, the turbomill has been used to produce intimate mixtures of high surface area powders and whiskers. Raw materials, TiN, AlN, and Al2O3, used to produce a titanium nitride/aluminum oxynitride (TiN/AlON) composite, were mixed in the turbomill, resulting in strength increases over samples prepared by dry ball milling. Using the turbomill as a leach vessel, it was found that 90.4 pct of the copper was extracted from the chalcopyrite during a 4-hour leach test in ferric sulfate versus conventional processing which involves either roasting of the ore for Cu recovery or leaching of the ore for several days.

The Use of Semitranslucent Rubber Pledgets During Microsurgical Dissection of Cerebellopontine Angle Tumors: Technical Note.

PubMed

Mazur, Marcus D; Gurgel, Richard; MacDonald, Joel D

2018-01-01

Dissection of cerebellopontine angle (CPA) tumors that abut or adhere to the brainstem or cranial nerves can be a challenging surgical endeavor. We describe the use of semitranslucent latex rubber pledgets in the tumor-brain interface as a method to improve visualization and protection of vital tissue during microsurgical dissection of CPA masses. The rubber pledgets are fashioned by cutting circular discs out of the cuff portion of talc-free, partially opaque latex gloves. These pledgets provide a semitranslucent, nonadherent membrane that can be placed between vital neural tissues and a tumor capsule to minimize trauma during dissection. The semitranslucent latex enables visualization of the underlying anatomical structures while also providing a protective surface onto which a suction device can be rested to facilitate clearance of the surgical field. A 56-yr-old woman with left ear tinnitus presented with a 3-cm CPA meningioma. During microsurgical dissection, rubber pledgets were used to preserve the interface between the brain stem, cranial nerves, and tumor capsule. The use of the rubber pledgets appeared to secure the interface between to tumor and the brain while at the same time protecting the cranial nerves, brainstem, and cerebellum. Semitranslucent rubber pledgets may facilitate microsurgical dissection of CPA tumors. Copyright © 2017 by the Congress of Neurological Surgeons

Mantle wedge infiltrated with saline fluids from dehydration and decarbonation of subducting slab.

PubMed

Kawamoto, Tatsuhiko; Yoshikawa, Masako; Kumagai, Yoshitaka; Mirabueno, Ma Hannah T; Okuno, Mitsuru; Kobayashi, Tetsuo

2013-06-11

Slab-derived fluids play an important role in heat and material transfer in subduction zones. Dehydration and decarbonation reactions of minerals in the subducting slab have been investigated using phase equilibria and modeling of fluid flow. Nevertheless, direct observations of the fluid chemistry and pressure-temperature conditions of fluids are few. This report describes CO2-bearing saline fluid inclusions in spinel-harzburgite xenoliths collected from the 1991 Pinatubo pumice deposits. The fluid inclusions are filled with saline solutions with 5.1 ± 1.0% (wt) NaCl-equivalent magnesite crystals, CO2-bearing vapor bubbles, and a talc and/or chrysotile layer on the walls. The xenoliths contain tremolite amphibole, which is stable in temperatures lower than 830 °C at the uppermost mantle. The Pinatubo volcano is located at the volcanic front of the Luzon arc associated with subduction of warm oceanic plate. The present observation suggests hydration of forearc mantle and the uppermost mantle by slab-derived CO2-bearing saline fluids. Dehydration and decarbonation take place, and seawater-like saline fluids migrate from the subducting slab to the mantle wedge. The presence of saline fluids is important because they can dissolve more metals than pure H2O and affect the chemical evolution of the mantle wedge.

Spinifex-textured komatiites in the south border of the Carajas ridge, Selva Greenstone belt, Carajás Province, Brazil

NASA Astrophysics Data System (ADS)

Siepierski, Lincoln; Ferreira Filho, Cesar Fonseca

2016-03-01

Spinifex-textured komatiites in the Selva greenstone belt are the first unequivocal examples of komatiites in the Transition Subdomain of the Carajás Mineral Province. Outcrops of spinifex-textured komatiites, located ∼1.5 km to the south of the Carajás ridge, were discovered during regional exploration for Ni-Cu-(PGE) sulfide deposits by VALE. They are associated with a 3.8 km long unit consisting of variable types of ultramafic rocks (talc schist, serpentinite and spinifex-textured komatiite). This ultramafic unit follows the steep dipping NW-SE trending Selva greenstone belt composed mainly by quartz-chlorite schists (interpreted as metasediments) and chlorite-actinolite schists (interpreted as metabasalts). Greenschist facies metamorphic parageneses characterize all rock types in the Selva greenstone belt. The komatiitic rocks in the Selva belt comprise a sequence of flows consisting of an upper spinifex-textured layer and a lower olivine cumulate layer. Although the spinifex and cumulus textures are well preserved in the field, the primary mineralogy of the komatiites has been completely replaced by greenschist facies metamorphic minerals. Platy olivine spinifex texture, consisting of an array of roughly parallel olivine plates, and random spinifex texture, consisting of randomly oriented olivine plates, are the most common primary volcanic textures in komatiites in the Selva greenstone belt. Platy and random spinifex texture is defined by former plates of olivine replaced by serpentine with minor actinolite, chlorite and magnetite, alternating with former matrix replaced by abundant actinolite and minor chlorite, talc, serpentine, and magnetite. The domains between olivine plates in both platy and random spinifex-textured rocks contain irregular arrays of fine-grained parallel crystals, representing primary fine-grained "quench" clinopyroxene crystals replaced by actinolite. Spinifex-textured komatiites have MgO contents bracket between 22.8 and 26.9 wt.%, and cumulate textured komatiites have MgO contents up to 40.6 wt.%. When plotted vs MgO contents, most major and minor elements fall on well-defined linear trends indicating control by olivine fractionation or accumulation. Komatiites from the Selva and Seringa (located in the Rio Maria Domain) belts are Al-undepleted with Al2O3/TiO2 ratios close to 20. Results for CaO, Na2O, and REE suggest that these elements were mobile and their abundances have been modified during metasomatic alteration. REE contents in some samples are very high (up to 40 times primitive mantle values) and REE patterns vary from flat (La/YbMN ∼ 1) to highly enriched in LREE (La/YbMN up to ∼ 10). The REE mobility may be related to hydrothermal alteration associated to Cu-Au mineralization in the region. The identification of spinifex-textured komatiites close to the Carajás Basin suggests the continuation of 3.0-2.9 Ga greenstone belts of the Rio Maria Domain within the Transition Subdomain, and enlarges the area with potential to host komatiite-associated Ni-Cu-PGE deposits.

The 10Å phase: a high-pressure expandable sheet silicate stable during subduction of hydrated lithosphere

NASA Astrophysics Data System (ADS)

Fumagalli, Patrizia; Stixrude, Lars; Poli, Stefano; Snyder, Don

2001-03-01

H 2O storage and release in deep subducting lithosphere is controlled by complex reaction suites involving a variety of hydrous phases. As a result of its relatively large thermal stability and intermediate composition, the 10Å phase (Mg 3Si 4O 10(OH) 2· nH 2O) has been regarded as a relevant H 2O reservoir in a wide range of rock compositions and mineral assemblages. High-pressure syntheses of the 10Å phase were carried out at 6.7 GPa and 650°C under fluid-saturated conditions in a Walker-type multi-anvil apparatus, from 5 min to 430 h. X-ray powder diffraction of large platy hexagonal crystals of the 10Å phase (up to 100 μm) were indexed on the basis of a trioctahedral-type structure. Long-term run products (>110 h) reveal sensitivity of the 10Å phase to treatment with acetone leading to the appearance of diffractions at greater d-spacings (10.2-11.6 Å) with respect to the basal peak of the 10Å phase (9.64-10.07 Å). This swelling behavior is strongly related to synthesis run duration. The Raman spectrum of the 10Å phase at frequencies less than 800 cm -1 shows a strong similarity to talc. In the Si-O stretching region (800-1100 cm -1), the 10Å phase exhibits three modes (909, 992 and 1058 cm -1), as compared to two in talc. The bending mode of water (ν 2) is found at 1593 cm -1. In the OH stretching region, peaks at 3593, 3622 and 3668 cm -1 were observed. The acetone treated sample shows a C-H stretching mode at 2923 cm -1 while the double bond CO signal is absent. The swelling behavior of the 10Å phase is interpreted as due to intercalation of acetone with pre-existing interlayer water. The efficiency of this process is dependent on the amount of the interlayer water which in turn depends on run duration. The relation between the response to acetone treatment and run duration is therefore interpreted as a time-dependent hydration of the 10Å phase. The fractions transformed from non-expandable to expandable fractions was fitted to the Avrami empirical law which suggests that kinetics are mainly controlled by diffusion rather than phase boundary reactions. The ability to accommodate variable amounts of H 2O makes the 10Å phase a major H 2O sink whenever a hydrous phase such as chlorite and serpentine breaks down during prograde transformations in the subducted lithosphere. Under H 2O-saturated conditions, a fully hydrated 10Å phase occurs; when H 2O-undersaturated conditions prevail, a H 2O-deficient 10Å phase incorporates the volatile component available. The exchange capacity of interlayer molecules in the 10Å phase structure opens new scenarios on the control of fluid compositions escaping from subducted slabs.

Investigating Reaction-Driven Cracking

NASA Astrophysics Data System (ADS)

Kelemen, P. B.; Hirth, G.; Savage, H. M.

2013-12-01

Many metamorphic reactions lead to large volume changes, and potentially to reaction-driven cracking [1,2]. Large-scale hydration of mantle peridotite to produce serpentine or talc is invoked to explain the rheology of plate boundaries, the nature of earthquakes, and the seismic properties of slow-spread ocean crust and the 'mantle wedge' above subduction zones. Carbonation of peridotite may be an important sink in the global carbon cycle. Zones of 100% magnesite + quartz replacing peridotite, up to 200 m thick, formed where oceanic mantle was thrust over carbonate-bearing metasediments in Oman. Talc + carbonate is an important component of the matrix in subduction mélanges at Santa Catalina Island , California, and the Sanbagawa metamorphic belt, Japan. Engineered systems to emulate natural mineral carbonation could provide relatively inexpensive CO2 capture and storage [3]. More generally, engineered reaction-driven cracking could supplement or replace hydraulic fracture in geothermal systems, solution mining, and extraction of tight oil and gas. The controls on reaction-driven cracking are poorly understood. Hydration and carbonation reactions can be self-limiting, since they potentially reduce permeability and armor reactive surfaces [4]. Also, in some cases, hydration or carbonation may take place at constant volume. Small changes in volume due to precipitation of solid products increases stress, destabilizing solid reactants, until precipitation and dissolution rates become equal at a steady state stress [5]. In a third case, volume change due to precipitation of solid products causes brittle failure. This has been invoked on qualitative grounds to explain, e.g., complete serpentinization of mantle peridotite [6]. Below ~ 300°C, the available potential energy for hydration and carbonation of olivine could produce stresses of 100's of MPa [2], sufficient to fracture rocks to 10 km depth or more, causing brittle failure below the steady state stress required for constant volume replacement. Natural examples have fracture energy densities due to strain energy density of 100's of MPa [2]. Despite theory and observation, until now lab experiments on peridotite hydration and carbonation have not produced reaction-driven cracking. Slow kinetics and limited reactive surface area in low porosity samples may be the cause. Also, maximum stress may be limited by 'disjoining pressure', above which nano-films along grain boundaries collapse, and crystal growth essentially ceases [7]. To address these issues, we've begun experiments on analog materials with fast reaction rates, e.g., CaO + H2O = Ca(OH)2, to efficiently investigate the role of confining pressure and other factors on reaction-driven fracture events. Intriguingly, commercially available 'demolition mortar', largely CaO, produces stresses of 70 MPa or more around 1 inch bore holes at room T and P [8], even though there is a free surface at the top of the borehole, and hydration in a 'closed' system creates ~ 40% air-filled pore space. [1] Jamtveit et al EPSL 08 [2] Kelemen & Hirth EPSL 12 [3] Kelemen et al AREPS 11 [4] Aharonov et al JGR 98 [5] Fletcher & Merino GCA 01 [6] Macdonald & Fyfe T'phys 85 [7] Espinosa-Marzal & Scherer GSL Special Papers 10 [8] Laefer et al Mag Concrete Res 10

Environmental contaminants as etiologic factors for diabetes.

PubMed Central

Longnecker, M P; Daniels, J L

2001-01-01

For both type 1 and type 2 diabetes mellitus, the rates have been increasing in the United States and elsewhere; rates vary widely by country, and genetic factors account for less than half of new cases. These observations suggest environmental factors cause both type 1 and type 2 diabetes. Occupational exposures have been associated with increased risk of diabetes. In addition, recent data suggest that toxic substances in the environment, other than infectious agents or exposures that stimulate an immune response, are associated with the occurrence of these diseases. We reviewed the epidemiologic data that addressed whether environmental contaminants might cause type 1 or type 2 diabetes. For type 1 diabetes, higher intake of nitrates, nitrites, and N-nitroso compounds, as well as higher serum levels of polychlorinated biphenyls have been associated with increased risk. Overall, however, the data were limited or inconsistent. With respect to type 2 diabetes, data on arsenic and 2,3,7,8-tetrachlorodibenzo-p-dioxin relative to risk were suggestive of a direct association but were inconclusive. The occupational data suggested that more data on exposure to N-nitroso compounds, arsenic, dioxins, talc, and straight oil machining fluids in relation to diabetes would be useful. Although environmental factors other than contaminants may account for the majority of type 1 and type 2 diabetes, the etiologic role of several contaminants and occupational exposures deserves further study. PMID:11744505

The improvement in functional characteristics of eco-friendly composites made of natural rubber and cellulose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Araki, Kunihiro; Kaneko, Shonosuke; Matsumoto, Koki

We investigated the efficient use of cellulose to resolve the problem of the depletion of fossil resources. In this study, as the biomass material, the green composite based on natural rubber (NR) and the flake-shaped cellulose particles (FSCP) was produced. In order to further improvement of functional characteristics, epoxidized natural rubber (ENR) was also used instead of NR. The FSCP were produced by mechanical milling in a planetary ball mill with a grinding aid as a cellulose aggregation inhibitor. Moreover, talc and mica particles were used to compare with FSCP. NR and ENR was mixed with vulcanizing agents and thenmore » each filler was added to NR compound in an internal mixer. The vulcanizing agents are as follows: stearic acid, zinc oxide, sulfur, and vulcanization accelerator. The functionalities of the composites were evaluated by a vibration-damping experiment and a gas permeability experiment. As a result, we found that FSCP filler has effects similar to (or more than) inorganic filler in vibration-damping and O{sub 2} barrier properties. And then, vibration- damping and O{sub 2} barrier properties of the composite including FSCP was increased with use of ENR. In particular, we found that ENR-50 composite containing 50 phr FSCP has three times as high vibration-damping property as ENR-50 without FSCP.« less

Investigation of internal structure of fine granules by microtomography using synchrotron X-ray radiation.

PubMed

Noguchi, Shuji; Kajihara, Ryusuke; Iwao, Yasunori; Fujinami, Yukari; Suzuki, Yoshio; Terada, Yasuko; Uesugi, Kentaro; Miura, Keiko; Itai, Shigeru

2013-03-10

Computed tomography (CT) using synchrotron X-ray radiation was evaluated as a non-destructive structural analysis method for fine granules. Two kinds of granules have been investigated: a bromhexine hydrochloride (BHX)-layered Celphere CP-102 granule coated with pH-sensitive polymer Kollicoat Smartseal 30-D, and a wax-matrix granule constructed from acetaminophen (APAP), dibasic calcium phosphate dehydrate, and aminoalkyl methacrylate copolymer E (AMCE) manufactured by melt granulation. The diameters of both granules were 200-300 μm. CT analysis of CP-102 granule could visualize the laminar structures of BHX and Kollicoat layers, and also visualize the high talc-content regions in the Kollicoat layer that could not be detected by scanning electron microscopy. Moreover, CT analysis using X-ray energies above the absorption edge of Br specifically enhanced the contrast in the BHX layer. As for granules manufactured by melt granulation, CT analysis revealed that they had a small inner void space due to a uniform distribution of APAP and other excipients. The distribution of AMCE revealed by CT analysis was also found to involve in the differences of drug dissolution from the granules as described previously. These observations demonstrate that CT analysis using synchrotron X-ray radiation is a powerful method for the detailed internal structure analysis of fine granules. Copyright © 2013 Elsevier B.V. All rights reserved.

Application of silver nanoparticles to the chemiluminescence determination of cefditoren pivoxil using the luminol-ferricyanide system.

PubMed

Alarfaj, Nawal A; Aly, Fatma A; El-Tohamy, Maha F

2015-02-01

A new simple, accurate and sensitive sequential injection analysis chemiluminescence (CL) detection method for the determination of cefditoren pivoxil (CTP) has been developed. The developed method was based on the enhancement effect of silver nanoparticles on the CL signal arising from a luminol-potassium ferricyanide reaction in the presence of CTP. The optimum conditions relevant to the effect of luminol, potassium ferricyanide and silver nanoparticle concentrations were investigated. The proposed method showed linear relationships between relative CL intensity and the investigated drug concentration at the range 0.001-5000 ng/mL, (r = 0.9998, n = 12) with a detection limit of 0.5 pg/mL and quantification limit of 0.001 ng/mL. The relative standard deviation was 1.6%. The proposed method was employed for the determination of CTP in bulk drug, in its pharmaceutical dosage forms and biological fluids such as human serum and urine. The interference of some common additive compounds such as glucose, lactose, starch, talc and magnesium stearate was investigated. In addition, the interference of some related cephalosporins was tested. No interference was recorded. The obtained sequential injection analysis-CL results were statistically compared with those from a reported method and did not show any significant differences. Copyright © 2014 John Wiley & Sons, Ltd.

Cancer mortality in a northern Italian cohort of rubber workers.

PubMed

Negri, E; Piolatto, G; Pira, E; Decarli, A; Kaldor, J; La Vecchia, C

1989-09-01

An analysis of the mortality of a cohort of 6629 workers employed from 1906 to 1981 in a rubber tyre factory in northern Italy (978 deaths and over 133,000 man-years at risk) showed that the all cause mortality ratio was slightly lower than expected (0.91). Overall cancer mortality was close to expected (275 v 259.4) but there were significant excess rates for two cancer sites: pleura (9 observed v 0.8 expected, which may be due to the use of fibre containing talc) and bladder (16 observed v 8.8 expected). Death rates were not raised for other sites previously associated with employment in the rubber industry, such as cancers of the lung and brain, leukaemias, or lymphomas. The substantially reduced relative risk of pleural cancer among workers first employed after 1940 (RR = 0.05 compared with before 1940) probably reflected improvements in working conditions over more recent periods. For cancer of the bladder, the relative risk was also lower for workers first engaged after 1940. Thus no appreciable risk for any disease was apparent for workers employed over the past four decades. Analysis for each of the 27 job categories showed a substantial excess for cancer of the pleura in the mechanical maintenance workers (4 observed v 0.17 expected); an excess of cancer of the lung (21 v 13.48) was also present in this job category.

Cancer mortality in a northern Italian cohort of rubber workers.

PubMed Central

Negri, E; Piolatto, G; Pira, E; Decarli, A; Kaldor, J; La Vecchia, C

1989-01-01

An analysis of the mortality of a cohort of 6629 workers employed from 1906 to 1981 in a rubber tyre factory in northern Italy (978 deaths and over 133,000 man-years at risk) showed that the all cause mortality ratio was slightly lower than expected (0.91). Overall cancer mortality was close to expected (275 v 259.4) but there were significant excess rates for two cancer sites: pleura (9 observed v 0.8 expected, which may be due to the use of fibre containing talc) and bladder (16 observed v 8.8 expected). Death rates were not raised for other sites previously associated with employment in the rubber industry, such as cancers of the lung and brain, leukaemias, or lymphomas. The substantially reduced relative risk of pleural cancer among workers first employed after 1940 (RR = 0.05 compared with before 1940) probably reflected improvements in working conditions over more recent periods. For cancer of the bladder, the relative risk was also lower for workers first engaged after 1940. Thus no appreciable risk for any disease was apparent for workers employed over the past four decades. Analysis for each of the 27 job categories showed a substantial excess for cancer of the pleura in the mechanical maintenance workers (4 observed v 0.17 expected); an excess of cancer of the lung (21 v 13.48) was also present in this job category. PMID:2789965

Environmental implication of subaqueous lava flows from a continental Large Igneous Province: Examples from the Moroccan Central Atlantic Magmatic Province (CAMP)

NASA Astrophysics Data System (ADS)

El Ghilani, S.; Youbi, N.; Madeira, J.; Chellai, E. H.; López-Galindo, A.; Martins, L.; Mata, J.

2017-03-01

The Late Triassic-Early Jurassic volcanic sequence of the Central Atlantic Magmatic Province (CAMP) of Morocco is classically subdivided into four stratigraphic units: the Lower, Middle, Upper and Recurrent Formations separated by intercalated sediments deposited during short hiatuses in volcanic activity. Although corresponding to a Large Igneous Province formed in continental environment, it contains subaqueous lava flows, including dominant pillowed flows but also occasional sheet flows. We present a study of the morphology, structure and morphometry of subaqueous lava flows from three sections located at the Marrakech High-Atlas (regions of Aït-Ourir, Jbel Imzar and Oued Lhar-Herissane), as well as an analysis of the sediments, in order to characterize them and to understand their environmental meaning. The analysis of clays by the diffraction method X-ray revealed the presence of illite, mica, phengite, céladonite, talc and small amounts of quartz, hematite, calcite and feldspar, as well as two pairs of interbedded irregular (chlorite Smectite/chlorite-Mica). Fibrous minerals such as sepiolite and palygorskite were not detected. The peperite of Herissane region (Central High Atlas) provided an excellent overview on the factors favoring the magma-sediment interaction. These are the products of a mixture of unconsolidated or poorly consolidated sediments, low permeability with a low viscosity magma. The attempt of dating palynology proved unfortunately without results.

Oxygen and hydrogen isotopic composition of the fluid during formation of anthophyllite metaultramafic rocks in the Sysert metamorphic complex, central Urals

NASA Astrophysics Data System (ADS)

Murzin, V. V.

2014-12-01

The oxygen (δ18O) and hydrogen (δD) isotopic composition of H2O-bearing minerals was studied for the ore-bearing amphibole metaultramafic rocks, which are the products of the early regional (435 ± 44 Ma) and late local (260 ± 6 Ma) silicic metasomatose in the Sysert metamorphic complex. The gold-sulfide mineralization of the Karas'evogorskoe deposit and anthophyllite-asbestos bodies of the Tersut deposit are related to the regional and local metasomatose combined with plagiogranitization and potassium granitization, respectively. The H2O-bearing minerals of metasomatites (anthophyllite, tremolite, talc) of the Karas'evogorskoe and Tersut deposits are characterized by heavier δ18O (9.8 to 12.2 and 7.6 to 9.4‰, respectively) and lighter ·D (87 to -91 and -56 to -67‰, respectively) values. The calculated isotopic composition of the fluid in equilibrium with these minerals indicates a heterogeneous source of water for the fluids related to the formation of metasomatites and the metamorphic origin of fluids. During the regional metasomatose, this fluid was a result of equilibrium of the deep fluid with volcanosedimentary rocks enriched in the heavy oxygen isotope. At the local metasomatose, the metamorphic fluid was formed by interaction of magmatic water produced by potassium granitization with ultramafic rocks.

Self-repairing properties of OPC clinker/natural zeolite blend in water and alkali carbonate environments at 270°C

DOE PAGES

Pyatina, Tatiana; Sugama, Toshifumi; Ronne, Arthur; ...

2018-01-01

The 10 d recoveries of the mechanical properties and crack sealing of an ordinary Portland cement (OPC) clinker/natural zeolite (ferrierite (Fer)) blend modified or unmodified with silica were tested at 270°C in water and alkali carbonate environments. The recoveries of the samples depended on their modification with silica and the curing environment, but were more than 100% after repeated damage under some test conditions. The mechanical properties and phase compositions of recovered samples were evaluated by compressive strength measurements and x-ray diffraction, differential thermogravimetric analyses, Fourier transform infrared analyses and scanning electron microscopy coupled with energy dispersive x-ray spectroscopy. Themore » sealing of 0·25 mm wide and ~2 mm deep cracks was visualised with a three-dimensional optical microscope. Fer decomposed under high-temperature alkaline conditions with the release of hydrolysates that, along with the hydrating clinker, participated in the formation of new phases contributing to strength recoveries. Here, these phases included crystalline magnesium and aluminium-containing silicates, calcium and carbonated calcium silicates and amorphous hydrates. Crack sealing was complete for the silica-modified samples and partial for unmodified ones cured in carbonate environments. The sealing was very poor for samples cured in water. Lastly, the main sealing phases included crystalline and amorphous silica, high-temperature-stable zeolites and talc mineral.« less

Mineral chemistry and geochemistry of ophiolitic metaultramafics from Um Halham and Fawakhir, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Abdel-Karim, Abdel-Aal M.; Ali, Shehata; El-Shafei, Shaimaa A.

2018-03-01

This study is focused on ophiolitic metaultramafics from Um Halham and Fawakhir, Central Eastern Desert of Egypt. The rocks include serpentinized peridotites, serpentinites together with talc- and quartz-carbonates. The primary spinel relict is Al-chromite [Cr# > 60], which is replaced by Cr-magnetite during metamorphism. The high Cr# of Al-chromites resembles supra-subduction zone (SSZ) peridotites and suggests derivation from the deeper portion of the mantle section with boninitic affinity. These mantle rocks equilibrated with boninitic melt have been generated by high melting degrees. The estimated melting degrees ( 19-24%) lie within the range of SSZ peridotites. The high Cr# of spinel and Fo content of olivine together with the narrow compositional range suggest a mantle residual origin. Serpentinized peridotite and serpentinites have low Al2O3/SiO2 ratios (mostly < 0.03) like fore-arc mantle wedge serpentinites and further indicate that their mantle protolith had experienced partial melting before serpentinization process. Moreover, they have very low Nb, Ta, Zr and Hf concentrations along with sub-chondritic Nb/Ta (0.3-16) and Zr/Hf (mostly 1-20) ratios further confirming that their mantle source was depleted by earlier melting extraction event. The high chondrite normalized (La/Sm)N ratios (average 10) reflect input of subduction-related slab melts/fluids into their mantle source.

Self-repairing properties of OPC clinker/natural zeolite blend in water and alkali carbonate environments at 270°C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pyatina, Tatiana; Sugama, Toshifumi; Ronne, Arthur

The 10 d recoveries of the mechanical properties and crack sealing of an ordinary Portland cement (OPC) clinker/natural zeolite (ferrierite (Fer)) blend modified or unmodified with silica were tested at 270°C in water and alkali carbonate environments. The recoveries of the samples depended on their modification with silica and the curing environment, but were more than 100% after repeated damage under some test conditions. The mechanical properties and phase compositions of recovered samples were evaluated by compressive strength measurements and x-ray diffraction, differential thermogravimetric analyses, Fourier transform infrared analyses and scanning electron microscopy coupled with energy dispersive x-ray spectroscopy. Themore » sealing of 0·25 mm wide and ~2 mm deep cracks was visualised with a three-dimensional optical microscope. Fer decomposed under high-temperature alkaline conditions with the release of hydrolysates that, along with the hydrating clinker, participated in the formation of new phases contributing to strength recoveries. Here, these phases included crystalline magnesium and aluminium-containing silicates, calcium and carbonated calcium silicates and amorphous hydrates. Crack sealing was complete for the silica-modified samples and partial for unmodified ones cured in carbonate environments. The sealing was very poor for samples cured in water. Lastly, the main sealing phases included crystalline and amorphous silica, high-temperature-stable zeolites and talc mineral.« less

Effect of Clinoptilolite and Sepiolite Nanoclays on Human and Parasitic Highly Phagocytic Cells

PubMed Central

Toledano-Magaña, Yanis; Flores-Santos, Leticia; Montes de Oca, Georgina; González-Montiel, Alfonso; Laclette, Juan-Pedro; Carrero, Julio-César

2015-01-01

Nanoclays have potential applications in biomedicine raising the need to evaluate their toxicity in in vitro models as a first approach to its biocompatibility. In this study, in vitro toxicity of clinoptilolite and sepiolite nanoclays (NC) was analyzed in highly phagocytic cultures of amoebas and human and mice macrophages. While amebic viability was significantly affected only by sepiolite NC at concentrations higher than 0.1 mg/mL, the effect on macrophage cultures was dependent on the origin of the cells. Macrophages derived from human peripheral blood monocytes were less affected in viability (25% decrease at 48 h), followed by the RAW 264.7 cell line (40%), and finally, macrophages derived from mice bone marrow monocytes (98%). Moreover, the cell line and mice macrophages die mainly by necrosis, whereas human macrophages exhibit increased apoptosis. Cytokine expression analysis in media of sepiolite NC treated cultures showed a proinflammatory profile (INFγ, IL-1α, IL-8, and IL-6), in contrast with clinoptilolite NC that induced lees cytokines with concomitant production of IL-10. The results show that sepiolite NC is more toxic to amoebas and macrophages than clinoptilolite NC, mostly in a time and dose-dependent manner. However, the effect of sepiolite NC was comparable with talc powder suggesting that both NC have low cytotoxicity in vitro. PMID:26090385

Conformational Changes of Bovine Serum Albumin Induced by Adsorption on Different Clay Surfaces: FTIR Analysis.

PubMed

Servagent-Noinville; Revault; Quiquampoix; Baron

2000-01-15

Interactions between proteins and clays perturb biological activity in ecosystems, particularly soil extracellular enzyme activity. The pH dependence of hydrophobic, hydrophilic, and electrostatic interactions on the adsorption of bovine serum albumin (BSA) is studied. BSA secondary structures and hydration are revealed from computation of the Amide I and II FTIR absorption profiles. The influence of ionization of Asp, Glu, and His side chains on the adsorption processes is deduced from correlation between p(2)H dependent carboxylic/carboxylate ratio and Amide band profiles. We quantify p(2)H dependent internal and external structural unfolding for BSA adsorbed on montmorillonite, which is an electronegative phyllosilicate. Adsorption on talc, a hydrophobic surface, is less denaturing. The results emphasize the importance of electrostatic interactions in both adsorption processes. In the first case, charged side chains directly influence BSA adsorption that generate the structural transition. In the second case, the forces that attract hydrophobic side chains toward the protein-clay interface are large enough to distort peripheral amphiphilic helical domains. The resulting local unfolding displaces enough internal ionized side chains to prevent them from establishing salt bridges as for BSA native structure in solution. On montmorillonite, a particular feature is a higher protonation of the Asp and Glu side chains of the adsorbed BSA than in solution, which decreases coulombic repulsion. Copyright 2000 Academic Press.

Application of photocuring technique on wood surface and its prospects in Bangladesh

NASA Astrophysics Data System (ADS)

Bhattcacharia, S. K.; Khan, Mubarak A.

2005-07-01

Photocuring technique has unveiled a new horizon in polymer science. Application of photocuring technique on wood surface has enhanced the use of low grade wood. As Bangladesh is an overpopulated country, necessity of good quality wood is increasing day by day. So low grade wood, like Simul or Partex, locally produced particleboard, would come out with great use. As Partex board, produced from Jute sticks and various types of indigenous low grade wood and particle board are abundant in Bangladesh, so photocuring could play a major role to improve the quality of low grade wood and serve the nation. Already, a lot of research works were carried out by the local scientists to improve the wood surface using UV curing method. Different formulations were also developed by the local scientists using various oligomer, monomer and different types of additives. The used oligomers are epoxy, polyester, urethane, etc. and monomers of different functionalities and used additives are acrylic monomer, CaCO3, sand, MgSiO3, talc, etc. Thin films were prepared on glass plate with different formulations using UV radiation and different characteristics properties (pendulum hardness, abrasion, gloss (60° and 20°), microscratch hardness, weathering effect, adhesion strength, etc.) were studied. Now, a Pilot Plant has already been established with the financial assistance by the government of Bangladesh, worth US 3.5 million.

Identification of possible sources of particulate matter in the personal cloud using SEM/EDX

NASA Astrophysics Data System (ADS)

Conner, Teri L.; Williams, Ronald W.

2004-10-01

The United States Environmental Protection Agency (US EPA) conducted the Baltimore Particulate Matter (PM) Epidemiology-Exposure Study of the Elderly during the summer of 1998. The study design included PM2.5 samples obtained from elderly (65+ years of age) retirement facility residents using personal exposure sampling devices. These sampling devices were also used to obtain PM2.5 samples at fixed locations within the personal monitoring subjects' apartments. Selected personal and apartment samples were examined using scanning electron microscopy with individual-particle X-ray analysis (SEM/EDX), providing a qualitative assessment of the chemical and physical characteristics of geological and trace element particles collected within these micro-environments at the retirement facility. This information was used to identify possible indoor source particles. The manual surveys of the personal samples revealed that some particles larger than 2.5 μm reached the filter surface. Using SEM/EDX, several particle types with possible indoor origins were identified. The Al-Zr-Cl particle is likely to have originated from a personal antiperspirant product. Particles with a talc or alumino-silicate composition point to cosmetics as a possible source. Large cadmium-containing particles were also found, which may indicate the use of art pigments or ceramic glazes, or emissions from television screen phosphors. A greater variety of particles was observed in a personal sample compared with its corresponding fixed-location apartment sample.

A new microcolumn flotation cell for determining the wettability and floatability of minerals.

PubMed

Ozkan, A; Yekeler, M

2003-05-15

Flotation is one of the most important physicochemical processes for mineral separations and other recovery operations. Flotation machines have been developed since the beginning of the 19th century and are still under intensive research and development. The cell we devised is a combination of the Canadian column flotation cell and the Partridge-Smith cell. The materials used for the construction of the new cell are cheap and use available laboratory accessories and aquarium materials. The cell functions well in terms of its scale, control, and sample requirement. It can be used both in the laboratory for research and in classrooms for demonstrations of experiments. Some of the data obtained by the flotation method using this cell are in good agreement with data measured independently on the same minerals by the contact angles method. The critical values of surface tension of wetting (gamma(c)) for talc, sulfur, and chemically treated surfaces of calcite and barite obtained by the contact angle measurements were 31, 26, 30.5, and 31.2 mN/m, respectively. On the other hand, the gamma(c) values of those minerals, obtained using our new designed flotation cell, were 30, 28, 31.4, and 34.5 mN/m, respectively. The measurements obtained in our experiment are also comparable to those previously published for the same minerals.

Dynamic CT imaging of volumetric changes in pulmonary nodules correlates with physical measurements of stiffness.

PubMed

Lartey, Frederick M; Rafat, Marjan; Negahdar, Mohammadreza; Malkovskiy, Andrey V; Dong, Xinzhe; Sun, Xiaoli; Li, Mei; Doyle, Timothy; Rajadas, Jayakumar; Graves, Edward E; Loo, Billy W; Maxim, Peter G

2017-02-01

A major challenge in CT screening for lung cancer is limited specificity when distinguishing between malignant and non-malignant pulmonary nodules (PN). Malignant nodules have different mechanical properties and tissue characteristics ('stiffness') from non-malignant nodules. This study seeks to improve CT specificity by demonstrating in rats that measurements of volumetric ratios in PNs with varying composition can be determined by respiratory-gated dynamic CT imaging and that these ratios correlate with direct physical measurements of PN stiffness. Respiratory-gated MicroCT images acquired at extreme tidal volumes of 9 rats with PNs from talc, matrigel and A549 human lung carcinoma were analyzed and their volumetric ratios (δ) derived. PN stiffness was determined by measuring the Young's modulus using atomic force microscopy (AFM) for each nodule excised immediately after MicroCT imaging. There was significant correlation (p=0.0002) between PN volumetric ratios determined by respiratory-gated CT imaging and the physical stiffness of the PNs determined from AFM measurements. We demonstrated proof of concept that PN volume changes measured non-invasively correlate with direct physical measurements of stiffness. These results may translate clinically into a means of improving the specificity of CT screening for lung cancer and/or improving individual prognostic assessments based on lung tumor stiffness. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Investigation of the composition of anabolic tablets using near infrared spectroscopy and Raman chemical imaging.

PubMed

Rebiere, Hervé; Ghyselinck, Céline; Lempereur, Laurent; Brenier, Charlotte

2016-01-01

The use of performance enhancing drugs is a widespread phenomenon in professional and leisure sports. A spectroscopic study was carried out on anabolic tablets labelled as 5 mg methandienone tablets provided by police departments. The analytical approach was based on a two-step methodology: a fast analysis of tablets using near infrared (NIR) spectroscopy to assess sample homogeneity based on their global composition, followed by Raman chemical imaging of one sample per NIR profile to obtain information on sample formulation. NIR spectroscopy assisted by a principal components analysis (PCA) enabled fast discrimination of different profiles based on the excipient formulation. Raman hyperspectral imaging and multivariate curve resolution - alternating least square (MCR-ALS) provided chemical images of the distribution of the active substance and excipients within tablets and facilitated identification of the active compounds. The combination of NIR spectroscopy and Raman chemical imaging highlighted dose-to-dose variations and succeeded in the discrimination of four different formulations out of eight similar samples of anabolic tablets. Some samples contained either methandienone or methyltestosterone whereas one sample did not contain an active substance. Other ingredients were sucrose, lactose, starch or talc. Both techniques were fast and non-destructive and therefore can be carried out as exploratory methods prior to destructive screening methods. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Effect of water on the rheology of enstatite

NASA Astrophysics Data System (ADS)

Zhang, G.; Mei, S.; Song, M.; Kohlstedt, D. L.

2015-12-01

The influence of water on the rheological properties of enstatite, the second principal constituent of the upper mantle, was investi­gated by performing high-temperature creep experiments under both hydrous and anhydrous conditions. Samples were fabricated from fine powered Bamble enstatite (Mg0.85Fe0.15SiO3) from Norway. Deformation experiments were carried out using a gas-medium apparatus at a confining pressure of 300 MPa and temperatures between 1123 and 1473 K. For experiments conducted under hydrous conditions, samples were encapsulated with a talc sleeve, which supplied water by the dehydration near 1075 K. Under our experimental conditions, deformation was dominated by diffusion creep as indicated by a stress exponent of ~1 for both anhydrous and hydrous conditions. Furthermore, our data yields activation energies of ~200 and ~400 kJ/mol for hydrous and anhydrous conditions, respectively. These values are smaller than those reported for enstatite deformed in the dislocation creep regime (820 kJ/mol, Mackwell, 1992; 600 kJ/mol, Lawlis, 1997). Importantly, our results demonstrate a strong influence of water on the diffusion creep of enstatite. Samples deformed under hydrous conditions crept ~1.5 order of magnitude faster than those deformed under anhydrous conditions at similar differential stresses and temperatures. This water-weakening effect is more than ten times greater than determined for olivine. Such results provide critical constraints needed for understanding the rheological behavior of Earth's interior.

Pneumoconiosis: Comparison of imaging and pathologic findings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chong, S.; Lee, K.S.; Chung, M.J.

2006-01-15

Pneumoconiosis may be classified as either fibrotic or nonfibrotic, according to the presence or absence of fibrosis. Silicosis, coal worker pneumoconiosis, asbestosis, berylliosis, and talcosis are examples of fibrotic pneumoconiosis. Siderosis, stannosis, and baritosis are nonfibrotic forms of pneumoconiosis that result from inhalation of iron oxide, tin oxide, and barium sulfate particles, respectively. In an individual who has a history of exposure to silica or coal dust, a finding of nodular or reticulonodular lesions at chest radiography or small nodules with a perilymphatic distribution at thin-section computed tomography (CT), with or without eggshell calcifications, is suggestive of silicosis or coalmore » worker pneumoconiosis. Magnetic resonance imaging is helpful for distinguishing between progressive massive fibrosis and lung cancer. CT and histopathologic findings in asbestosis are similar to those in idiopathic pulmonary fibrosis, but the presence of asbestos bodies in histopathologic specimens is specific for the diagnosis of asbestosis. Giant cell interstitial pneumonia due to exposure to hard metals is classified as a fibrotic form of pneumoconiosis and appears on CT images as mixed ground-glass opacities and reticulation. Berylliosis simulates pulmonary sarcoidosis on CT images. CT findings in talcosis include small centrilobular and subpleural nodules or heterogeneous conglomerate masses that contain foci of high attenuation indicating talc deposition. Siderosis is nonfibrotic and is indicated by a CT finding of poorly defined centrilobular nodules or ground-glass opacities.« less

Evaluation of joint effusion in rabbits by color Doppler, power Doppler, and contrast-enhanced power Doppler ultrasonography.

PubMed

Lim, Gye-Yeon; Im, Soo Ah; Jung, Won Sang; Lee, Jae Mun; Lee, Ah Won

2005-09-01

The aim of this prospective study was to evaluate the diagnostic value of power Doppler ultrasonography (PDUS) and contrast-enhanced PDUS (CEPDUS) in the depiction and characterization of experimentally induced arthritis in the rabbit. Thirty rabbits were divided into three groups consisting of one control group (saline injection group) and two experimental groups: a suppurative arthritis group and a chemically induced synovitis group. The same amount (1 ml) of each agent was directly injected into the right hip joint. Serial color Doppler ultrasound (CDUS), PDUS, and CEPDUS images were obtained before and after injection. We observed that all of the infected knees in the suppurative arthritis group with Staphylococcus aureus demonstrated an increased signal on PDUS after inoculation. A minimal power Doppler signal was presented in the chemically induced synovitis group with talc injection, but none of the control knees demonstrated any increased signals. CEPDUS was the most sensitive imaging modality for evaluating the increase of blood flows in suppurative arthritis and was subsequently followed by PDUS and CDUS. The increased signals obtained with PDUS represent increased local blood flows; therefore, this technique can be used for evaluating the degree of inflammation. Furthermore, using the contrast agent enhances the sensitivity of PDUS, and it can even be useful for differentiating borderline cases. Copyright 2005 Wiley Periodicals, Inc

Formulation of Indomethacin Colon Targeted Delivery Systems Using Polysaccharides as Carriers by Applying Liquisolid Technique

PubMed Central

Elkhodairy, Kadria A.; Elsaghir, Hanna A.; Al-Subayiel, Amal M.

2014-01-01

The present study aimed at the formulation of matrix tablets for colon-specific drug delivery (CSDD) system of indomethacin (IDM) by applying liquisolid (LS) technique. A CSDD system based on time-dependent polymethacrylates and enzyme degradable polysaccharides was established. Eudragit RL 100 (E-RL 100) was employed as time-dependent polymer, whereas bacterial degradable polysaccharides were presented as LS systems loaded with the drug. Indomethacin-loaded LS systems were prepared using different polysaccharides, namely, guar gum (GG), pectin (PEC), and chitosan (CH), as carriers separately or in mixtures of different ratios of 1 : 3, 1 : 1, and 3 : 1. Liquisolid systems that displayed promising results concerning drug release rate in both pH 1.2 and pH 6.8 were compressed into tablets after the addition of the calculated amount of E-RL 100 and lubrication with magnesium stearate and talc in the ratio of 1 : 9. It was found that E-RL 100 improved the flowability and compressibility of all LS formulations. The release data revealed that all formulations succeeded to sustain drug release over a period of 24 hours. Stability study indicated that PEC-based LS system as well as its matrix tablets was stable over the period of storage (one year) and could provide a minimum shelf life of two years. PMID:24971345

Case Report: Analytical Electron Microscopy of Lung Granulomas Associated with Exposure to Coating Materials Carried by Glass Wool Fibers

PubMed Central

Ferreira, Angela S.; Moreira, Valéria B.; Castro, Marcos César S.; Soares, Porfírio J.; Algranti, Eduardo; Andrade, Leonardo R.

2010-01-01

Context Man-made vitreous fibers (MMVFs) are noncrystalline inorganic fibrous material used for thermal and acoustical insulation (e.g., rock wool, glass wool, glass microfibers, and refractory ceramic fibers). Neither epidemiologic studies of human exposure nor animal studies have shown a noticeable hazardous effect of glass wools on health. However, MMVFs have been anecdotally associated with granulomatous lung disease in several case reports. Case presentation Here, we describe the case of a patient with multiple bilateral nodular opacities who was exposed to glass wool fibers and coating materials for 7 years. Bronchoalveolar lavage fluid revealed an increased total cell count (predominantly macrophages) with numerous cytoplasmic particles. Lung biopsy showed peribronchiolar infiltration of lymphoid cells and many foreign-body–type granulomas. Alveolar macrophages had numerous round and elongated platelike particles inside the cytoplasm. X-ray microanalysis of these particles detected mainly oxygen/aluminum/silicon and oxygen/magnesium/silicon, compatible with kaolinite and talc, respectively. No elemental evidence for glass fibers was found in lung biopsy. Discussion The contribution of analytical electron microscopy applied in the lung biopsy was imperative to confirm the diagnosis of pneumoconiosis associated with a complex occupational exposure that included both MMVFs and coating materials. Relevance to clinical or professional practice This case study points out the possible participation of other components (coating materials), beyond MMVFs, in the etiology of pneumoconiosis. PMID:20123612

Plastic Deformation of Quartz: Unfinished business?

NASA Astrophysics Data System (ADS)

Paterson, M. S.

2011-12-01

Starting at Harvard in the mid-1930's, David Griggs built a series of high pressure machines for experimental rock deformation. One persistent aim was to achieve the plastic deformation of quartz. Each time he built a new machine for higher pressure and/or temperature, one of the first materials he tested would be quartz. This search went on through a 500 MPa liquid-medium machine at temperatures up to 300°C, then with a gas-medium machine for temperatures up to 800°C, and finally with a solid-medium machine for higher pressures and temperatures. Quartz proved stubbornly resistant to deformation except at extremely high stresses until, finally and somewhat serendipitously, it was found possible to deform quartz at relatively low stresses in the presence of water under special conditions. The breakthrough came in an experiment in a 1500 MPa solid-medium apparatus in which talc was used as pressure medium. At the temperature of the experiment, the talc dehydrated and so released water. Under these conditions, natural quartz proved to be very weak and to readily undergo plastic deformation, a phenomenon that became known as "hydrolytic weakening". Soon after this discovery, it was also found that certain synthetic single crystals could be easily deformed ab initio. These crystals were from a particular set that had been grown rapidly under hydrothermal conditions and had incorporated water during growth. Attempts in our laboratory to weaken crystals in a gas-medium apparatus at around 300 MPa by cooking dry quartz in the presence of added water were all unsuccessful, although we could deform wet synthetic crystals. There was considerable speculation about a role of high pressure in promoting hydrolytic weakening, but the dilemma was eventually clarified by electron microscope studies by Fitz Gerald and coworkers. These studies showed that crystals that had been subjected to high pressure and temperature in the solid-medium apparatus were extensively microcracked, presumably due to non-hydrostatic stresses generated from the solid medium during raising the pressure, thus evidently promoting the ingress of water. From our gas-medium experiments it would seem that both the solubility and the rate of diffusion of water-related species in dry quartz must be very low, such that at 300 MPa and around 500 - 1000 °C the water penetrates less than a few micrometres in the course of a few hours. Thus the sluggishness of diffusion and the low equilibrium solubility of water-related species in quartz probably explain the failure to achieve hydrolytic weakening in the gas-medium apparatus. However, the documentation of these properties remains inadequate. The initial, and still current, Frank-Griggs hypothesis for the origin of hydrolytic weakening is that the water plays a role in the breaking of the covalent silicon-oxygen bonds as a dislocation is propagated. It is a corollary that the dislocation must be saturated with water or that the water must migrate with the dislocation as it moves. Heggie and Jones have done a number of ab initio calculations on the role of the water in the migration of dislocations in quartz which support the idea that the motion of dislocations is aided by the presence of water-related species in the dislocation core.

Fluid-related modifications of Cr-spinel and olivine from ophiolitic peridotites by contact metamorphism of granitic intrusions in the Ablah area, Saudi Arabia

NASA Astrophysics Data System (ADS)

Ahmed, Ahmed Hassan; Surour, Adel Abdullah

2016-05-01

The Ablah serpentinized peridotites and overlying layered metagabbros represent an allochthonous piece of a dismembered ophiolite in the southern Hijaz terrane that belongs to the Neoproterozoic Arabian Shield in Saudi Arabia. On both sides, the ophiolite is bounded by wider domains of granitic intrusions and volcano-sedimentary successions, all together follow a N-S trend. The protolith of the Ablah serpentinized peridotites is mainly harzburgite which is partly or totally serpentinized. Carbonate veins of variable sizes invade and hydrate the serpentinized peridotites. Away from the contact with the granitic intrusions, fresh primary (igneous) olivine and Cr-spinel are preserved in the partly serpentinized peridotites. These relict primary minerals are used to infer their tectonic setting of formation as a nascent spreading center rock association of mid-ocean ridge or back-arc basin setting. Based on the re-distribution of elements related to different thermal effects, three patterns of Cr-spinel modification can be defined. The first pattern can be followed in the partly serpentinized peridotites where Cr-spinel displays simple zoning that is characterized by sharp contact between primary Al-rich cores and secondary Fe3+-rich rims. These cores and rims are homogeneous and show progressive decrease in Mg, Al and Cr, but with remarkable increase in Fe3+ and Fe2+ toward the rims. Mineral assemblage in equilibrium with this type of Cr-spinel is primary olivine + antigorite + chlorite ± talc ± chrysotile. The second pattern of Cr-spinel modification is represented by homogeneous weakly zoned Cr-rich spinel with no distinct sharp contacts between Cr-rich cores and magnetite rims. Cr-spinel cores of this type are rich in Cr and Fe2+, and poor in Mg, Al and Fe3+. The mineral assemblage in equilibrium with this Cr-spinel type is Fe-rich olivine + antigorite + enstatite + chlorite + tremolite + anthophyllite ± talc. The third pattern is defined by pervasive heterogeneous modification in which the alteration starts from the cores outwards forming a very characteristic "atoll" textured SiO2- and Cr-rich porous spinel. This type is characterized by core-to-rim increase in Cr, Fe3+, Si, Mn, Ni and Ti, and decrease in Mg, Al and Fe2+. The mineral assemblage in equilibrium with this pattern is chlorite + carbonates + lizardite/chrysotile ± antigorite. The first modification pattern is suggested to form under nearly solid-state conditions in the distal part from the granitic intrusion. The second pattern could be formed under reducing conditions with high temperature and fluid/rock ratio near the contact zone. The peak metamorphic temperature of this stage ranges from 500 to 650 °C that indicate upper amphibolite facies conditions. During retrograde metamorphism, the hydrothermal fluids are cooler and oxidizing which lead to the precipitation of thick marble-like carbonate veins within the serpentinized peridotites. In such a case, the aqueous fluids attack the Al- and Mg-rich cores, which are less resistant and replicable than the Fe-rich rims, and form the third chemical modification pattern of porous SiO2-rich spinel. The high SiO2 content in Cr-spinel is most probably attributed to the formation of Mg- and Al-rich silicates within the sub-microscopic pores of altered Cr-spinel.

Investigating the effects of abyssal peridotite alteration on Si, Mg and Zn isotopes

NASA Astrophysics Data System (ADS)

Savage, P. S.; Wimpenny, J.; Harvey, J.; Yin, Q.; Moynier, F.

2013-12-01

Around 1/3 of Earth's divergent ridge system is now classified as "slow" spreading [1], exposing ultramafic rocks (abyssal peridotites) at the seafloor. Such material is often highly altered by serpentinisation and steatisation (talc formation). It is crucial to understand such processes in order to access the original composition of the mantle, and to quantify any impact on ocean composition. Here we examine the effect of both serpentinisation and steatisation on Si, Mg and Zn isotopes. Hydrothermal alteration and seafloor weathering are both sources of oceanic Si [2] and weathering of abyssal peridotites is a source of oceanic Mg [3]; hence isotopic fractionation as a result of seafloor alteration could affect oceanic Si and Mg isotope composition. Zinc isotopes can provide complimentary information; the magnitude and direction of fractionation is highly dependent on complexing ligand [4] and can provide compositional information on the fluids driving metasomatism. For this study, two cores from the well-characterised abyssal peridotites recovered on ODP Leg 209 were examined [5]. Hole 1274a peridotites exhibit variable serpentinisation at ~200°C, whereas samples from Hole 1268a have been comprehensively serpentinised and then subsequently steatised to talc facies at ~350°C, by a low Mg/Si, low pH fluid. The Si, Mg and Zn isotope compositions of 1274a samples are extremely homogeneous, identical to that of pristine mantle rocks (BSE) i.e., serpentinisation at this locality was predominantly isochemical [5]. In contrast, samples from 1268a show greater isotopic variability. In all samples, Mg is enriched in the heavier isotopes relative to BSE, consistent with formation of isotopically heavy secondary phases [6]. For Si, serpentinised samples are slightly enriched in the lighter isotopes compared to BSE, again consistent with the behaviour of Si during formation of secondary phases [7]. Within the steatised samples, some exhibit enrichments in the lighter Si isotopes (similar to the serpentinites), however, some are isotopically heavy, relative to BSE. Such samples were found to have abundant chlorite, whose formation requires fluid with high Al activity, likely sourced from late-emplaced gabbroic dykes. The Zn of all 1268a samples are enriched in the lighter isotopes, implying the involvement of isotopically light sulfide precipitation during metasomatism [4]. The consistently heavy Mg isotope data suggest that seafloor alteration of peridotites can input an isotopically light Mg-bearing fluid to the ocean. Fluid composition is less easy to determine from the more complex behaviour observed in Si isotopes, although it is unlikely to substantially deviate from BSE, consistent with previous observations [8]. Finally, the strong enrichment in the lighter isotopes of Zn confirms that this isotope system could be used as a tracer of recycled serpentinised material at arc settings, as suggested in [4]. [1] Dick et al. (2003) Nature 426, 405-412; [2] Treguer and De La Rocha (2013) Ann. Rev. Mar. Sci. 5, 477-501; [3] Snow & Dick (1995) GCA, 59, 4219-4235; [4] Pons et al. (2011) PNAS 108(43) 17639-17643; [5] Bach et al., (2004) G3 5; [6] Tipper et al. (2006) EPSL 247, 267-279; [7] Opfergelt et al. (2012) Chem. Geol. 326, 113-122; [8] De La Rocha et al. (2000) GCA 64, 2467-2477.

Structural characterization of magnesium silicate hydrate: towards the design of eco-sustainable cements.

PubMed

Tonelli, M; Martini, F; Calucci, L; Fratini, E; Geppi, M; Ridi, F; Borsacchi, S; Baglioni, P

2016-02-28

Magnesium-based cement is one of the most interesting eco-sustainable alternatives to standard cementitious binders. The reasons for the interest towards this material are twofold: (i) its production process, using magnesium silicates, brine or seawater, dramatically reduces CO2 emissions with respect to Portland cement production, and (ii) it is very well suited to applications in radioactive waste encapsulation. In spite of its potential, assessment of the structural properties of its binder phase (magnesium silicate hydrate or M-S-H) is far from complete, especially because of its amorphous character. In this work, a comprehensive structural characterization of M-S-H was obtained using a multi-technique approach, including a detailed solid-state NMR investigation and, in particular, for the first time, quantitative (29)Si solid-state NMR data. M-S-H was prepared through room-temperature hydration of highly reactive MgO and silica fume and was monitored for 28 days. The results clearly evidenced the presence in M-S-H of "chrysotile-like" and "talc-like" sub-nanometric domains, which are approximately in a 1 : 1 molar ratio after long-time hydration. Both these kinds of domains have a high degree of condensation, corresponding to the presence of a small amount of silanols in the tetrahedral sheets. The decisive improvement obtained in the knowledge of M-S-H structure paves the way for tailoring the macroscopic properties of eco-sustainable cements by means of a bottom-up approach.

Preliminary Assessment of Non-Fuel Mineral Resources of Afghanistan, 2007

USGS Publications Warehouse

,

2007-01-01

Introduction Afghanistan has abundant mineral resources, including known deposits of copper, iron, barite, sulfur, talc, chromium, magnesium, salt, mica, marble, rubies, emeralds, lapis lazuli, asbestos, nickel, mercury, gold and silver, lead, zinc, fluorspar, bauxite, beryllium, and lithium (fig. 1). Between 2005 and 2007, the U.S. Agency for International Development (USAID) funded a cooperative study by the U.S. Geological Survey (USGS) and the Afghanistan Geological Survey (AGS) to assess the non-fuel mineral resources of Afghanistan as part of the effort to aid in the reconstruction of that country. An assessment is an estimation or evaluation, in this instance of undiscovered non-fuel mineral resources. Mineral resources are materials that are in such form that economic extraction of a commodity is currently or potentially feasible. In this assessment, teams of scientists from the USGS and the AGS compiled information about known mineral deposits and then evaluated the possible occurrence of undiscovered deposits of all types. Quantitative probabilistic estimates were made for undiscovered deposits of copper, mercury, rare-earth elements, sulfur, chromite, asbestos, potash, graphite, and sand and gravel. These estimates were made for undiscovered deposits at depths less than a kilometer. Other deposit types were considered and discussed in the assessment, but quantitative estimates of numbers of undiscovered deposits were not made. In addition, the assessment resulted in the delineation of 20 mineralized areas for further study, of which several may contain resources amenable to rapid development.

Medical qualification of a commercial spaceflight participant: not your average astronaut.

PubMed

Jennings, Richard T; Murphy, David M F; Ware, David L; Aunon, Serena M; Moon, Richard E; Bogomolov, Valery V; Morgun, Valeri V; Voronkov, Yuri I; Fife, Caroline E; Boyars, Michael C; Ernst, Randy D

2006-05-01

Candidates for commercial spaceflight may be older than the typical astronaut and more likely to have medical problems that place them at risk during flight. Since the effects of microgravity on many medical conditions are unknown, physicians have little guidance when evaluating and certifying commercial spaceflight participants. This dynamic new era in space exploration may provide important data for evaluating medical conditions, creating appropriate medical standards, and optimizing treatment alternatives for long-duration spaceflight. A 57-yr-old spaceflight participant for an ISS mission presented with medical conditions that included moderately severe bullous emphysema, previous spontaneous pneumothorax with talc pleurodesis, a lung parenchymal mass, and ventricular and atrial ectopy. The medical evaluation required for certification was extensive and included medical studies and monitoring conducted in analogue spaceflight environments including altitude chambers, high altitude mixed-gas simulation, zero-G aircraft, and high-G centrifuge. To prevent recurrence of pneumothorax, we performed video-assisted thoracoscopic pleurodesis, and to assess lung masses, several percutaneous or direct biopsies. The candidate's 10-d mission was without incident. Non-career astronauts applying for commercial suborbital and orbital spaceflight will, at least in the near future, challenge aerospace physicians with unknowns regarding safety during training and flight, and highlight important ethical and risk-assessment problems. The information obtained from this new group of space travelers will provide important data for the evaluation and in-flight treatment of medical problems that space programs have not yet addressed systematically, and may improve the medical preparedness of exploration-class missions.

Asbestos contamination in feldspar extraction sites: a failure of prevention? Commentary.

PubMed

Cavariani, Fulvio

2016-01-01

Fibrous tremolite is a mineral species belonging to the amphibole group. It is present almost everywhere in the world as a natural contaminant of other minerals, like talc and vermiculite. It can be also found as a natural contaminant of the chrysotile form of asbestos. Tremolite asbestos exposures result in respiratory health consequences similar to the other forms of asbestos exposure, including lung cancer and mesothelioma. Although abundantly distributed on the earth's surface, tremolite is only rarely present in significant deposits and it has had little commercial use. Significant presence of amphibole asbestos fibers, characterized as tremolite, was identified in mineral powders coming from the milling of feldspar rocks extracted from a Sardinian mining site (Italy). This evidence raises several problems, in particular the prevention of carcinogenic risks for the workers. Feldspar is widespread all over the world and every year it is produced in large quantities and it is used for several productive processes in many manufacturing industries (over 21 million tons of feldspar mined and marketed every year). Until now the presence of tremolite asbestos in feldspar has not been described, nor has the possibility of such a health hazard for workers involved in mining, milling and handling of rocks from feldspar ores been appreciated. Therefore the need for a wider dissemination of knowledge of these problems among professionals, in particular mineralogists and industrial hygienists, must be emphasized. In fact both disciplines are necessary to plan appropriate environmental controls and adequate protections in order to achieve safe working conditions.

Development and Validation of a Chromatography Method Using Tandem UV/Charged Aerosol Detector for Simultaneous Determination of Amlodipine Besylate and Olmesartan Medoxomil: Application to Drug-Excipient Compatibility Study

PubMed Central

Brondi, Ariadne M.; Garcia, Jerusa S.

2017-01-01

A study was carried out to investigate compatibility of amlodipine besylate and olmesartan medoxomil with a variety of pharmaceutical excipients. Both drugs are antihypertensive agents that can be administered alone, in monotherapy, or in pharmaceutical association. The studies were performed using binary and ternary mixtures, and samples were stored for 3 and 6 months at 40°C under 75% relative humidity and dry conditions. For this study, a method based on high-performance liquid chromatography (HPLC) was developed and validated for the simultaneous determination of amlodipine besylate and olmesartan medoxomil in samples from pharmaceutical preformulation studies using diode array detector (DAD) and charged aerosol detector (CAD). The runtime per sample was 10 min with retention time of 7.926 min and 4.408 min for amlodipine and olmesartan, respectively. The validation was performed according to ICH guidelines. The calibration curve presents linear dynamic range from 12 to 250 μg mL−1 for amlodipine and from 25 to 500 μg mL−1 for olmesartan with coefficient of determination (R2 ≥ 0.9908) while repeatability and reproducibility (expressed as relative standard deviation) were lower than 1.0%. The excipients such as corn starch, croscarmellose sodium, magnesium stearate, polyvinyl alcohol, talc, polyvinylpyrrolidone, lactose monohydrate, and polyethylene glycol showed potential incompatibilities after accelerated stability testing. PMID:29391967

Developing Asbestos Job Exposure Matrix Using Occupation and Industry Specific Exposure Data (1984-2008) in Republic of Korea.

PubMed

Choi, Sangjun; Kang, Dongmug; Park, Donguk; Lee, Hyunhee; Choi, Bongkyoo

2017-03-01

The goal of this study is to develop a general population job-exposure matrix (GPJEM) on asbestos to estimate occupational asbestos exposure levels in the Republic of Korea. Three Korean domestic quantitative exposure datasets collected from 1984 to 2008 were used to build the GPJEM. Exposure groups in collected data were reclassified based on the current Korean Standard Industrial Classification (9 th edition) and the Korean Standard Classification of Occupations code (6 th edition) that is in accordance to international standards. All of the exposure levels were expressed by weighted arithmetic mean (WAM) and minimum and maximum concentrations. Based on the established GPJEM, the 112 exposure groups could be reclassified into 86 industries and 74 occupations. In the 1980s, the highest exposure levels were estimated in "knitting and weaving machine operators" with a WAM concentration of 7.48 fibers/mL (f/mL); in the 1990s, "plastic products production machine operators" with 5.12 f/mL, and in the 2000s "detergents production machine operators" handling talc containing asbestos with 2.45 f/mL. Of the 112 exposure groups, 44 groups had higher WAM concentrations than the Korean occupational exposure limit of 0.1 f/mL. The newly constructed GPJEM which is generated from actual domestic quantitative exposure data could be useful in evaluating historical exposure levels to asbestos and could contribute to improved prediction of asbestos-related diseases among Koreans.

Viral Pollution of Surface Waters Due to Chlorinated Primary Effluents

PubMed Central

Sattar, Syed A.; Westwood, J. C. N.

1978-01-01

The role of chlorinated primary effluents in viral pollution of the Ottawa River (Ontario) was assessed by examining 282 field samples of wastewaters from two different sewage treatment plants over a 2-year period. The talc-Celite technique was used for sample concentration, and BS-C-1 cells were employed for virus detection. Viruses were detected in 80% (75/94) of raw sewage, 72% (68/94) of primary effluent, and 56% (53/94) of chlorinated effluent samples. Both raw sewage and primary effluent samples contained about 100 viral infective units (VIU) per 100 ml. Chlorination produced a 10- to 50-fold reduction in VIU and gave nearly 2.7 VIU/100 ml of chlorinated primary effluent. With a combined daily chlorinated primary effluent output of approximately 3.7 × 108 liters, these two plants were discharging 1.0 × 1010 VIU per day. Because the river has a mean annual flow of 8.0 × 1010 liters per day, these two sources alone produced a virus loading of 1.0 VIU/8 liters of the river water. This river also receives at least 9.0 × 107 liters of raw sewage per day and undetermined but substantial amounts of storm waters and agricultural wastes. It is used for recreation and acts as a source of potable water for some 6.0 × 105 people. In view of the potential of water for disease transmission, discharge of such wastes into the water environment needs to be minimized. PMID:215085

Theoretical predictions of volatile bearing phases and volatile resources in some carbonaceous chondrites

NASA Technical Reports Server (NTRS)

Ganguly, Jibamitra; Saxena, Surendra K.

1989-01-01

Carbonaceous chondrites are usually believed to be the primary constituents of near-Earth asteroids and Phobos and Diemos, and are potential resources of fuels which may be exploited for future planetary missions. The nature and abundances are calculated of the major volatile bearing and other phases, including the vapor phase that should form in C1 and C2 type carbonaceous chondrites as functions of pressure and temperature. The results suggest that talc, antigorite plus or minus magnesite are the major volatile bearing phases and are stable below 400 C at 1 bar in these chondritic compositions. Simulated heating of a kilogram of C2 chondrite at fixed bulk composition between 400 and 800 C at 1 bar yields about 135 gm of volatile, which is made primarily of H2O, H2, CH4, CO2 and CO. The relative abundances of these volatile species change as functions of temperature, and on a molar basis, H2 becomes the most dominant species above 500 C. In contrast, Cl chondrites yield about 306 gm of volatile under the same condition, which consist almost completely of 60 wt percent H2O and 40 wt percent CO2. Preliminary kinetic considerations suggest that equilibrium dehydration of hydrous phyllosilicates should be attainable within a few hours at 600 C. These results provide the framework for further analyses of the volatile and economic resource potentials of carbonaceous chondrites.

Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images

USGS Publications Warehouse

Crowley, J.K.; Brickey, D.W.; Rowan, L.C.

1989-01-01

Airborne imaging spectrometer data collected in the near-infrared (1.2-2.4 ??m) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure-the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration. ?? 1989.

Surface clay formation during short-term warmer and wetter conditions on a largely cold ancient Mars

NASA Astrophysics Data System (ADS)

Bishop, Janice L.; Fairén, Alberto G.; Michalski, Joseph R.; Gago-Duport, Luis; Baker, Leslie L.; Velbel, Michael A.; Gross, Christoph; Rampe, Elizabeth B.

2018-03-01

The ancient rock record for Mars has long been at odds with climate modelling. The presence of valley networks, dendritic channels and deltas on ancient terrains points towards running water and fluvial erosion on early Mars1, but climate modelling indicates that long-term warm conditions were not sustainable2. Widespread phyllosilicates and other aqueous minerals on the Martian surface3-6 provide additional evidence that an early wet Martian climate resulted in surface weathering. Some of these phyllosilicates formed in subsurface crustal environments5, with no association with the Martian climate, while other phyllosilicate-rich outcrops exhibit layered morphologies and broad stratigraphies7 consistent with surface formation. Here, we develop a new geochemical model for early Mars to explain the formation of these clay-bearing rocks in warm and wet surface locations. We propose that sporadic, short-term warm and wet environments during a generally cold early Mars enabled phyllosilicate formation without requiring long-term warm and wet conditions. We conclude that Mg-rich clay-bearing rocks with lateral variations in mixed Fe/Mg smectite, chlorite, talc, serpentine and zeolite occurrences formed in subsurface hydrothermal environments, whereas dioctahedral (Al/Fe3+-rich) smectite and widespread vertical horizonation of Fe/Mg smectites, clay assemblages and sulphates formed in variable aqueous environments on the surface of Mars. Our model for aluminosilicate formation on Mars is consistent with the observed geological features, diversity of aqueous mineralogies in ancient surface rocks and state-of-the-art palaeoclimate scenarios.

Frictional properties of saponite-rich gouge from a serpentinite-bearing fault zone along the Gokasho-Arashima Tectonic Line, central Japan

USGS Publications Warehouse

Sone, Hiroki; Shimamoto, Toshihiko; Moore, Diane E.

2012-01-01

We studied a serpentinite-bearing fault zone in Gokasho-Arashima Tectonic Line, Mie Prefecture, central Japan, characterizing its internal structures, mineral assemblage, permeability, and frictional properties. The fault core situated between the serpentinite breccia and the adjacent sedimentary rocks is characterized by a zone locally altered to saponite. The clayey gouge layer separates fault rocks of serpentinite origin containing talc and tremolite from fault rocks of sedimentary origin containing chlorite but no quartz. The minerals that formed within the fault are the products of metasomatic reaction between the serpentinite and the siliceous rocks. Permeability measurements show that serpentinite breccia and fault gouge have permeability of 10−14–10−17 m2 and 10−15–10−18 m2, respectively, at 5–120 MPa confining pressure. Frictional coefficient of the saponite-rich clayey fault gouge ranged between 0.20 and 0.35 under room-dry condition, but was reduced to 0.06–0.12 when saturated with water. The velocity dependence of friction was strongly positive, mostly ranging between 0.005 and 0.006 in terms of a–b values. The governing friction law is not constrained yet, but we find that the saponite-rich gouge possesses an evolutional behavior in the opposite direction to that suggested by the rate and state friction law, in addition to its direct velocity dependence.

Elemental analysis of silicon based minerals by ultrasonic slurry sampling electrothermal vaporisation ICP-MS.

PubMed

Rodríguez, Pablo Fernández; Marchante-Gayón, Juan Manuel; Sanz-Medel, Alfredo

2006-01-15

Ultrasonic slurry sampling electrothermal vaporisation inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) was applied to the elemental analysis of silicate based minerals, such as talc or quartz, without any pre-treatment except the grinding of the sample. The electrothermal vaporisation device consists of a tungsten coil connected to a home-made power supply. The voltage program, carrier gas flow rate and sonication time were optimised in order to obtain the best sensitivity for elements determined. The relationship between the amount of sample in the slurry and the signal intensity was also evaluated. Unfortunately, in all cases, quantification had to be carried out by the standard additions method owing to the strong matrix interferences. The global precision of the proposed method was always better than 12%. The limits of detection, calculated as three times the standard deviation of the blank value divided by the slope of the calibration curve, were between 0.5 ng/g for As and 3.5 ng/g for Ba. The method was validated by comparing the concentrations found for Cu, Mn, Cr, V, Li, Pb, Sn, Mg, U, Ba, Sr, Zn, Sb, Rb and Ce using the proposed methodology with those obtained by conventional nebulisation ICP-MS after acid digestion of the samples in a microwave oven. The concentration range in the solid samples was between 0.2 microg/g for Cr and 60 microg/g for Ba. All results were statistically in agreement with those found by conventional nebulisation.

Mesothelioma and other lung disease in taconite miners; the uncertain role of non-asbestiform EMP.

PubMed

Mandel, Jeffrey H; Odo, Nnaemeka U

2018-04-10

The purpose of this paper was to assess the role of non-asbestiform amphibole EMPs in the etiology of mesotheliomas and other lung disease in taconite (iron ore) miners. Increased mesothelioma rates have been described in Minnesota taconite workers since the late 1990s. Currently, over 100 cases have been reported by the Minnesota Department of Health within the complete cohort of miners in Minnesota. Geologic sampling has indicated that only the eastern part of the iron range contains non-asbestiform amphibole elongate mineral particles (EMPs), in close proximity to the ore. This type of EMP has been less studied and also exists in talc and gold mining. A series of investigations into the state's taconite industry have been recently completed. Results from a cohort mortality study indicated an SMR of 2.77 (95% CI = 1.87-3.96) for mesothelioma. In a case-control study, the odds ratio for mesothelioma for high vs. low EMP exposure was 2.25 (5% CI = 1.13-4.5) but EMPs in this study were counted by phase contrast microscopy. Odds ratios were not elevated in mines located in the eastern part of the Mesabi iron range. The overall findings suggest that mesothelioma in taconite miners is related to EMP exposure. Because of the way EMPs were counted, results from these studies cannot allow a firm conclusion about the association between EMP exposure and the reported excess mesothelioma. Copyright © 2018 Elsevier Inc. All rights reserved.

Hydrothermal frictional strengths of rock and mineral samples relevant to the creeping section of the San Andreas Fault

USGS Publications Warehouse

Moore, Diane E.; Lockner, David A.; Hickman, Stephen H.

2016-01-01

We compare frictional strengths in the temperature range 25–250 °C of fault gouge from SAFOD (CDZ and SDZ) with quartzofeldspathic wall rocks typical of the central creeping section of the San Andreas Fault (Great Valley sequence and Franciscan Complex). The Great Valley and Franciscan samples have coefficients of friction, μ > 0.35 at all experimental conditions. Strength is unchanged between 25° and 150 °C, but μ increases at higher temperatures, exceeding 0.50 at 250 °C. Both samples are velocity strengthening at room temperature but show velocity-weakening behavior beginning at 150 °C and stick-slip motion at 250 °C. These rocks, therefore, have the potential for unstable seismic slip at depth. The CDZ gouge, with a high saponite content, is weak (μ = 0.09–0.17) and velocity strengthening in all experiments, and μ decreases at temperatures above 150 °C. Behavior of the SDZ is intermediate between the CDZ and wall rocks: μ < 0.2 and does not vary with temperature. Although saponite is probably not stable at depths greater than ∼3 km, substitution of the frictionally similar minerals talc and Mg-rich chlorite for saponite at higher temperatures could potentially extend the range of low strength and stable slip down to the base of the seismogenic zone.

Structure and properties of binder gels formed in the system Mg(OH)2-SiO2-H2O for immobilisation of Magnox sludge.

PubMed

Walling, Sam A; Kinoshita, Hajime; Bernal, Susan A; Collier, Nick C; Provis, John L

2015-05-07

A cementitious system for the immobilisation of magnesium rich Magnox sludge was produced by blending an Mg(OH)2 slurry with silica fume and an inorganic phosphate dispersant. The Mg(OH)2 was fully consumed after 28 days of curing, producing a disordered magnesium silicate hydrate (M-S-H) with cementitious properties. The structural characterisation of this M-S-H phase by (29)Si and (25)Mg MAS NMR showed clearly that it has strong nanostructural similarities to a disordered form of lizardite, and does not take on the talc-like structure as has been proposed in the past for M-S-H gels. The addition of sodium hexametaphosphate (NaPO3)6 as a dispersant enabled the material to be produced at a much lower water/solids ratio, while still maintaining the fluidity which is essential in practical applications, and producing a solid monolith. Significant retardation of M-S-H formation was observed with larger additions of phosphate, however the use of 1 wt% (NaPO3)6 was beneficial in increasing fluidity without a deleterious effect on M-S-H formation. This work has demonstrated the feasibility of using M-S-H as binder to structurally immobilise Magnox sludge, enabling the conversion of a waste into a cementitious binder with potentially very high waste loadings, and providing the first detailed nanostructural description of the material thus formed.

Development of novel fast-dissolving tacrolimus solid dispersion-loaded prolonged release tablet.

PubMed

Cho, Jung Hyun; Kim, Yong-Il; Kim, Dong-Wuk; Yousaf, Abid Mehmood; Kim, Jong Oh; Woo, Jong Soo; Yong, Chul Soon; Choi, Han-Gon

2014-04-11

The goal of this research was to develop a novel prolonged release tablet bioequivalent to the commercial sustained release capsule. A number of tacrolimus-loaded fast-dissolving solid dispersions containing various amounts of DOSS were prepared using the spray drying technique. Their solubility, dissolution and pharmacokinetics in rats were studied. DOSS increased drug solubility and dissolution in the solid dispersions. Compared with the drug powder, the solubility, dissolution and bioavailability of tacrolimus with the fast-dissolving solid dispersion containing tacrolimus/HP-β-CD/DOSS in the weight ratio of 5:40:4 were boosted by approximately 700-, 30- and 2-fold, respectively. Several tablet formulations were accomplished with this solid dispersion in combination with various ratios of HPMC/ethylcellulose. The release behaviour and pharmacokinetic studies in beagle dogs were assessed compared with the commercial prolonged release capsule. A decrease in HPMC/ethylcellulose ratios reduced the dissolution of tacrolimus from the tablets. Particularly, the tacrolimus-loaded prolonged release tablet consisting of fast-dissolving tacrolimus solid dispersion, HPMC, ethylcellulose and talc at the weight ratio of 20:66:112:2 exhibited a dissolution profile similar to that produced by the commercial prolonged release capsule. Furthermore, there were no significant differences in the AUC, Cmax, Tmax and MRT values between them in beagle dogs. Consequently, this tacrolimus-loaded prolonged release tablet might be bioequivalent to the tacrolimus-loaded commercial capsule. Copyright © 2013 Elsevier B.V. All rights reserved.

Antibiotic-producing Pseudomonas fluorescens mediates rhizome rot disease resistance and promotes plant growth in turmeric plants.

PubMed

Prabhukarthikeyan, S R; Keerthana, U; Raguchander, T

2018-05-01

Rhizome rot of turmeric caused by Pythium aphanidermatum is a major threat to turmeric-cultivating areas of India. This study intends to evaluate the performance of fluorescent pseudomonads against Rhizome rot disease and understand the resistance mechanism in Turmeric plants. Fluorescent pseudomonads were screened against Pythium aphanidermatum using dual culture. Selected strains were evaluated for the performance of growth promoting attributes and the presence of antibiotic genes through PCR analysis. Strain FP7 recorded the maximum percent inhibition of P. aphanidermatum under in vitro conditions. Strains FP7 and TPF54 both increased plant growth in turmeric plants in vitro. Strain FP7 alone contained all the evaluated antibiotic biosynthetic genes. Talc and liquid-based formulations were prepared with effective strain and tested for its biocontrol activities under both glasshouse and field conditions. Enzymatic activities of the induced defense enzymes such as PO, PPO, PAL, CAT and SOD were estimated and subjected to spectrophotometric analysis. A combination of rhizome dip and soil drench of FP7 liquid formulation treatment remarkably recorded the minimum disease incidence, higher defense enzymes, maximum plant growth and yield under glasshouse and field conditions. Application of strain FP7 increased the defense molecules, plant growth and yield in turmeric plants thereby reducing the incidence of rhizome rot disease. Moreover, this study has a potential to be adopted for sustainable and eco-friendly turmeric production. Copyright © 2018 Elsevier GmbH. All rights reserved.

Usefulness of Medical Thoracoscopy in the Management of Pleural Effusion Caused by Chronic Renal Failure.

PubMed

Colella, Sara; Fioretti, Federica; Massaccesi, Chiara; Primomo, Gian L; Panella, Gianluca; D'Emilio, Vittorio; Pela, Riccardo

2017-10-01

Although pleural effusion (PE) can be caused by several pathologies like congestive heart failure, infections, malignancies, and pulmonary embolism, it is also a common finding in chronic kidney disease (CKD). Diagnostic thoracentesis is of limited value in the differential diagnosis, and the role of more invasive investigations like medical thoracoscopy (MT) is still unclear. To evaluate the usefulness of MT in unexplained PE in CKD. In the electronic database of our Institution, we retrospectively searched for patients with CKD who underwent MT for unexplained PE between January 2008 and August 2016. Ten patients were included in the present study. The average age was 72.4 years, the male:female ratio 9:1 and the average blood creatinine value 5.96 mg/dL. The average follow-up was 18 months.A thoracentesis showed an exudate was found in 9 patients and in 1 case pleural fluid characteristics were not recorded for technical reasons; in none of them the cytologic or microbiological analyses were considered diagnostic.The clinical suspicion was a neoplastic (5) or an infectious disease (5). In 4 patients with recurrent PE, MT was performed to obtain talc pleurodesis.No immediate procedure-related complications were recorded; 1 patient developed empyema after 2 months. In 6 cases final diagnosis was chronic uremic pleuritis, hydrothorax in 2, and chronic lymphocytic pleurisy in 2. MT represents a safe and effective diagnostic and therapeutic procedure in patients with CKD, that itself is a common cause of exudative effusion, and those patients may not require MT.

Adaptation of pharmaceutical excipients to FDM 3D printing for the fabrication of patient-tailored immediate release tablets.

PubMed

Sadia, Muzna; Sośnicka, Agata; Arafat, Basel; Isreb, Abdullah; Ahmed, Waqar; Kelarakis, Antonios; Alhnan, Mohamed A

2016-11-20

This work aims to employ fused deposition modelling 3D printing to fabricate immediate release pharmaceutical tablets with several model drugs. It investigates the addition of non-melting filler to methacrylic matrix to facilitate FDM 3D printing and explore the impact of (i) the nature of filler, (ii) compatibility with the gears of the 3D printer and iii) polymer: filler ratio on the 3D printing process. Amongst the investigated fillers in this work, directly compressible lactose, spray-dried lactose and microcrystalline cellulose showed a level of degradation at 135°C whilst talc and TCP allowed consistent flow of the filament and a successful 3D printing of the tablet. A specially developed universal filament based on pharmaceutically approved methacrylic polymer (Eudragit EPO) and thermally stable filler, TCP (tribasic calcium phosphate) was optimised. Four model drugs with different physicochemical properties were included into ready-to-use mechanically stable tablets with immediate release properties. Following the two thermal processes (hot melt extrusion (HME) and fused deposition modelling (FDM) 3D printing), drug contents were 94.22%, 88.53%, 96.51% and 93.04% for 5-ASA, captopril, theophylline and prednisolone respectively. XRPD indicated that a fraction of 5-ASA, theophylline and prednisolone remained crystalline whilst captopril was in amorphous form. By combining the advantages of thermally stable pharmaceutically approved polymers and fillers, this unique approach provides a low cost production method for on demand manufacturing of individualised dosage forms. Copyright © 2016 Elsevier B.V. All rights reserved.

Equivalence between three scattering formulations for ultrasonic wave propagation in particulate mixtures

NASA Astrophysics Data System (ADS)

Challis, R. E.; Tebbutt, J. S.; Holmes, A. K.

1998-12-01

The aim of this paper is to present a unified approach to the calculation of the complex wavenumber for a randomly distributed ensemble of homogeneous isotropic spheres suspended in a homogeneous isotropic continuum. Three classical formulations of the diffraction problem for a compression wave incident on a single particle are reviewed; the first is for liquid particles in a liquid continuum (Epstein and Carhart), the second for solid or liquid particles in a liquid continuum (Allegra and Hawley), and the third for solid particles in a solid continuum (Ying and Truell). Equivalences between these formulations are demonstrated and it is shown that the Allegra and Hawley formulation can be adapted to provide a basis for calculation in all three regimes. The complex wavenumber that results from an ensemble of such scatterers is treated using the formulations of Foldy (simple forward scattering), Waterman and Truell, and Lloyd and Berry (multiple scattering). The analysis is extended to provide an approximation for the case of a distribution of particle sizes in the mixture. A number of experimental measurements using a broadband spectrometric technique (reported elsewhere) to obtain the attenuation coefficient and phase velocity as functions of frequency are presented for various mixtures of differing contrasts in physical properties between phases in order to provide a comparison with theory. The materials used were aqueous suspensions of polystyrene spheres, silica spheres, iron spheres, 0022-3727/31/24/012/img1 pigment (AHR), droplets of 1-bromohexadecane, and a suspension of talc particles in a cured epoxy resin.

Paper analytical devices for fast field screening of beta lactam antibiotics and antituberculosis pharmaceuticals.

PubMed

Weaver, Abigail A; Reiser, Hannah; Barstis, Toni; Benvenuti, Michael; Ghosh, Debarati; Hunckler, Michael; Joy, Brittney; Koenig, Leah; Raddell, Kellie; Lieberman, Marya

2013-07-02

Reports of low-quality pharmaceuticals have been on the rise in the past decade, with the greatest prevalence of substandard medicines in developing countries, where lapses in manufacturing quality control or breaches in the supply chain allow substandard medicines to reach the marketplace. Here, we describe inexpensive test cards for fast field screening of pharmaceutical dosage forms containing beta lactam antibiotics or combinations of the four first-line antituberculosis (TB) drugs. The devices detect the active pharmaceutical ingredients (APIs) ampicillin, amoxicillin, rifampicin, isoniazid, ethambutol, and pyrazinamide and also screen for substitute pharmaceuticals, such as acetaminophen and chloroquine that may be found in counterfeit pharmaceuticals. The tests can detect binders and fillers such as chalk, talc, and starch not revealed by traditional chromatographic methods. These paper devices contain 12 lanes, separated by hydrophobic barriers, with different reagents deposited in the lanes. The user rubs some of the solid pharmaceutical across the lanes and dips the edge of the paper into water. As water climbs up the lanes by capillary action, it triggers a library of different chemical tests and a timer to indicate when the tests are completed. The reactions in each lane generate colors to form a "color bar code" which can be analyzed visually by comparison with standard outcomes. Although quantification of the APIs is poor compared with conventional analytical methods, the sensitivity and selectivity for the analytes is high enough to pick out suspicious formulations containing no API or a substitute API as well as formulations containing APIs that have been "cut" with inactive ingredients.

Geochemical characterisation of seepage and drainage water quality from two sulphide mine tailings impoundments: Acid mine drainage versus neutral mine drainage

USGS Publications Warehouse

Heikkinen, P.M.; Raisanen, M.L.; Johnson, R.H.

2009-01-01

Seepage water and drainage water geochemistry (pH, EC, O2, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.

The effect of mineral reactions and microstructure on long-term experimental fault zone weakening

NASA Astrophysics Data System (ADS)

Niemeijer, Andre R.

2017-04-01

The frictional properties of fault rocks and, in particular, the velocity dependence of friction and associated rate-and-state parameters, are thought to exert an important control on earthquake nucleation and propagation. Experimental results obtained from natural fault gouges typically show that the velocity dependence of friction is a function of both temperature and sliding velocity, indicating that thermally activated time-dependent processes are fundamentally responsible for causing velocity-weakening behavior in silicate-bearing gouges at earthquake "nucleation velocities" (˜ 1 μm/s) and temperatures around 150-300 ˚ C. In addition, slow experiments at velocities of 10s of nm/s using three different fault gouge types all exhibit major weakening with ongoing displacement at constant velocity. Microstructural and microanalytical analyses demonstrate that the development of a weak through-going foliation as well as the (shear-enhanced) formation of new, weak minerals such as talc or muscovite occurred, which both presumably contributed to the observed weakening. Importantly, the slow deformation rates allow for time-dependent viscous deformation (e.g. pressure solution) to occur at low shear stress within the hard, frictionally strong minerals such as quartz. The results highlight the importance of the chemical effects of fluids and microstructural development on long-term fault weakening under slow loading conditions. The resultant frictionally weak fault gouges allow strain to remain localized, yield a strong permeability anisotropy and provide a barrier for rupture propagation. Along-fault variations in the chemical conditions thus have the potential to produce strong contrasts in frictional properties, which can have a large effect on potential earthquake rupture size and style.

Paper analytical devices for fast field screening of beta lactam antibiotics and anti-tuberculosis pharmaceuticals

PubMed Central

Weaver, Abigail A.; Reiser, Hannah; Barstis, Toni; Benvenuti, Michael; Ghosh, Debarati; Hunckler, Michael; Joy, Brittney; Koenig, Leah; Raddell, Kellie; Lieberman, Marya

2013-01-01

Reports of low quality pharmaceuticals have been on the rise in the last decade with the greatest prevalence of substandard medicines in developing countries, where lapses in manufacturing quality control or breaches in the supply chain allow substandard medicines to reach the marketplace. Here, we describe inexpensive test cards for fast field screening of pharmaceutical dosage forms containing beta lactam antibiotics or combinations of the four first-line antituberculosis (TB) drugs. The devices detect the active pharmaceutical ingredients (APIs) ampicillin, amoxicillin, rifampicin, isoniazid, ethambutol, and pyrazinamide, and also screen for substitute pharmaceuticals such as acetaminophen and chloroquine that may be found in counterfeit pharmaceuticals. The tests can detect binders and fillers like chalk, talc, and starch not revealed by traditional chromatographic methods. These paper devices contain twelve lanes, separated by hydrophobic barriers, with different reagents deposited in the lanes. The user rubs some of the solid pharmaceutical across the lanes and dips the edge of the paper into water. As water climbs up the lanes by capillary action, it triggers a library of different chemical tests and a timer to indicate when the tests are completed. The reactions in each lane generate colors to form a “color bar code” which can be analyzed visually by comparison to standard outcomes. While quantification of the APIs is poor compared to conventional analytical methods, the sensitivity and selectivity for the analytes is high enough to pick out suspicious formulations containing no API or a substitute API, as well as formulations containing APIs that have been “cut” with inactive ingredients. PMID:23725012

The mineral resources of the Sierra Nevada de Santa Marta, Columbia (Zone I)

USGS Publications Warehouse

Tschanz, Charles McFarland; Jimeno V., Andres; Cruz, Jaime B.

1970-01-01

The Sierra Nevada de Santa Maria on the north coast of Colombia is an isolated triangular mountain area that reaches altitudes of almost 19,000 feet. The exceedingly complex geology is shown on the 1:200,000 geologic map. Despite five major periods of granitic intrusion, three major periods of metamorphism, and extensive volcanic eruptions, metallic deposits are small and widely scattered. Sulfide deposits of significant economic value appear to be absent. Many small copper deposits, of chalcocite, cuprite, malachite, and azurite are found in epidotized rock in Mesozoic redbeds and intercalated volcanic rocks, but their economic potential is very small. Deposits of other common base metals appear to be absent. The most important metallic deposits may prove to be unusual bimineralic apatite-ilmenite deposits associated with gneissic anorthosite. The known magnetite deposits are too small to be exploited commercially. Primary gold deposits have not been identified and the placer deposits are uneconomic and very small. The largest and most important deposits are nonmetallic. Enormous reserves of limestone are suitable for cement manufacture and some high-purity limestone is suitable for the most exacting chemical uses. Small deposits of talc-tremolite could be exploited locally for ceramic use. The important noncoking bituminous coal deposits in the Cerrej6n area are excluded from this study. Other nonmetallic resources include igneous dimension stone in a variety of colors and textures, and agricultural dolomite. There probably are important undeveloped ground water resources on the slopes of the wide Rancheria and Cesar valleys, which separate the Sierra Nevada from the Serrania de Persia.

The detection of drugs of abuse in fingerprints using Raman spectroscopy II: cyanoacrylate-fumed fingerprints

NASA Astrophysics Data System (ADS)

Day, Joanna S.; Edwards, Howell G. M.; Dobrowski, Steven A.; Voice, Alison M.

2004-07-01

This paper describes the application of Raman spectroscopy to the detection of exogenous substances in cyanoacrylate-fumed fingerprints. The scenario considered was that of an individual handling a substance and subsequently depositing a contaminated fingerprint. These fingerprints were enhanced by cyanoacrylate fuming, a process in which a layer of white cyanoacrylate polymer is deposited on the fingerprint material, enabling visual detection. Five drugs of abuse (codeine phosphate, cocaine hydrochloride, amphetamine sulphate, barbital and nitrazepam) and five non-controlled substances of similar appearance, which may be used in the adulteration of drugs of abuse (caffeine, aspirin, paracetamol, starch and talc), were used. The substances studied could be clearly distinguished using their Raman spectra and were all successfully detected in cyanoacrylate-fumed fingerprints. Photobleaching was necessary to reduce the fluorescence background in the spectra of some substances. Raman spectra obtained from the substances in cyanoacrylate-fumed fingerprints were of a similar quality to spectra obtained from the substances under normal sampling conditions, however, interfering Raman bands arising from the cyanoacrylate polymer were present in the spectra. In most cases the only interfering band was the CN stretching mode of the polymer, and there were no cases where the interfering bands prevented identification of the substances. If necessary, the interfering bands could be successfully removed by spectral subtraction. The most difficult aspect of the detection of these substances in cyanoacrylate-fumed fingerprints was visually locating the substance in the fingerprint beneath the polymer layer in order to obtain a Raman spectrum.

Videothoracoscopy in the treatment of spontaneous pneumothorax: an initial experience.

PubMed Central

Waller, D. A.; Yoruk, Y.; Morritt, G. N.; Forty, J.; Dark, J. H.

1993-01-01

We report an initial experience with the new and potentially advantageous technique of videothoracoscopy in the treatment of pneumothorax. A series of 18 consecutive patients (14 male, 4 female) presenting with spontaneous pneumothorax over a 4-month period underwent surgical treatment by this method. The indication for surgery was recurrent pneumothorax in nine patients and persistent air leak in the remainder (median duration 15 days, range 5-28 days). Stapled apical bullectomy with apical parietal pleurectomy was performed in 14 patients, bullectomy alone was performed in one patient and pleurectomy alone in three patients. Additional talc pleurodesis was carried out in three of these patients. Median duration of operation was 53.5 min (range 35-120 min). The median postoperative drainage was 300 ml in 24 h (range 50-580 ml). The median duration of intercostal drainage was 48 h (range 24-384 h) and of postoperative hospital stay 4 days (range 3-18 days). The mean postoperative analgesic requirement was 1.3 mg morphine/h. Three complications required reoperation. In two patients a large air leak persisted after operation; one proceeded to thoracotomy for suturing of the air leak and in the other this was accomplished by videothoracoscopy. A further patient re-presented at 2 weeks with recurrent pneumothorax which was treated at thoracotomy. At a median follow-up of 68.5 days (range 10-124 days) this is the only recurrence. These complications were caused by errors in surgical technique early in our series. This initial experience of videothoracoscopic pleurectomy suggests it is an effective, well-tolerated treatment of spontaneous pneumothorax. PMID:8379623

Ultramafic-derived arsenic in a fractured bedrock aquifer

USGS Publications Warehouse

Ryan, P.C.; Kim, J.; Wall, A.J.; Moen, J.C.; Corenthal, L.G.; Chow, D.R.; Sullivan, C.M.; Bright, K.S.

2011-01-01

In the fractured bedrock aquifer of northern Vermont, USA, As concentrations in groundwater range from <1 to 327??g/L (<13-4360nm/L) and these elevated occurrences have a general spatial association with ultramafic rock bodies. The ultramafic rocks in this region are comprised mainly of serpentinites and talc-magnesite rocks with average As concentration of 93ppm and a range from 1 to 1105ppm. By comparison, the other main lithologies in the study area are depleted in As relative to the ultramafics: the average As concentration in metabasaltic rocks is 4.1ppm with a range of <1-69ppm, and mean As concentration in meta-sedimentary phyllites and schists is 22ppm with a range of <1-190ppm. In the ultramafic rocks, As is correlated with Sb and light rare earth elements, indicating that As was introduced to the ultramafic rocks during metasomatism by fluids derived from the subducting slab. Evidence from sequential chemical extraction, X-ray diffraction (XRD) and stoichiometric analysis indicates that the majority of the As is located in antigorite and magnesite (MgCO3) with lesser amounts in magnetite (Fe3O4). Hydrochemistry of monitoring wells drilled into fractured ultramafic rock in a groundwater recharge area with no anthropogenic As source reveals above background As (2-9??g/L) and an Mg-HCO3 hydrochemical signature that reflects dissolution of antigorite and magnesite, confirming that As in groundwater can be derived from ultramafic rock dissolution. Arsenic mobility in groundwater affected by ultramafic rock dissolution may be enhanced by alkaline pH values and relatively high HCO3- concentrations. ?? 2011 Elsevier Ltd.

The mineral industry of Ethiopia: present conditions and future prospects

NASA Astrophysics Data System (ADS)

Assefa, Getaneh

Despite a record of mineral activity that dates back to Biblical times and the occurrence of a wide variety of minerals, as well as continuing efforts to discover major ore deposits, Ethiopia's mineral resources ahve remained of minor importance in the world economy. Mineral production in the last 20 years, for example, forms less than 1% of the estimated GDP. Well known minerals andmineral products available in the country in commercial quantities are: gold, platinum, manganese ore, natural agas, clays and clay products, feldspars, gypsum and anhydrite, slat, lime, limestone, cement, sand, structural and crushed stones, marble, mineral water and pumice. There are also vast reserves of water and geothermal power. Recently discovered deposits (over the last 20 years), with major reserves that may attain an important role in mineral production in the future, include potash salts, copper ore and diatomites. Minerals which are known to occur in Ethiopia, but of which supplies are deficient, or which have not yet been proved to exist in economic quantities are: nickel, iron, chromium, mineral fuels (oil, coal and uranium), sulphur, asbesttos, mica, talc, barytes, fluorites, borates, soda-ash, phosphates, wolframite, abrasives (garnet), molybdenite and vanadium. Within the last few years there has been an increasing appreciation of the economic significance of a mineral industry and a definite attempt to foster it. Mineral ownership is vested in the state are cotnrolled by the MInistry of Mines, Energy and Water Resources. The law relating to foreign investment in mines is liberal. The plans for the future have to provide for detailed and intensive exploration of the country's mineral resources, manufacture and fabrication.

Laser-Raman microprobe identification of inclusions in capsules associated with silicone gel breast implants.

PubMed

Centeno, J A; Mullick, F G; Panos, R G; Miller, F W; Valenzuela-Espinoza, A

1999-07-01

Raman spectroscopy (the analysis of scattered photons after excitation with a monochromatic light source) provides a nondestructive method for identifying organic and inorganic materials on the basis of the molecule's characteristic spectrum of vibrational frequencies. Although the technique has been predominantly applied in sciences other than pathology, the recent advent of high-quality microscope optics coupled to optical Raman spectrometers (a variation known as a Raman microprobe) rendered this technique amenable to applications in human pathology. In the Raman microprobe, a laser beam is focused on a spot approximately 1 microm in diameter on the surface of the sample, e.g., tissue, and the scattered light is collected and analyzed. In this investigation, we used the Raman microprobe for the identification of foreign materials in breast implant capsular tissues. The characteristic silicone group frequencies associated with the silicon-oxygen stretch, the silicone-carbon stretch, the silicon-methyl and the methyl carbon-hydrogen stretch frequencies were used to identify polydimethylsiloxane and to define chemical differences among the various other implant-related inclusions. All of the inclusions were positively identified in a series of 44 capsules from silicone gel-filled implants: polydimethylsiloxane was found in 44 of 44 capsules surrounding silicone gel-filled implants; polyurethane was seen in 4 of 4 capsules around polyurethane foam-coated gel-filled implants; 4 of 4 capsules enveloping Dacron patch gel-filled implants revealed Dacron; and talc was identified in 8 of these 44 capsules. Raman microspectroscopy provides a rapid, accurate, and sensitive method for identifying inclusions associated with silicone and other implant materials in tissue.

Temperature and rate of dehydration of major constituents of carbonaceous chondrites under vacuum conditions

NASA Astrophysics Data System (ADS)

Pohl, Leos; Britt, Daniel

2017-10-01

Some sub-types of carbonaceous chondrites contain a significant amount of hydrated minerals which produce specific absorption lines, typically due to the presence of hydroxyls. However, if these asteroids have come close enough to the Sun during their history, the high temperatures might have resulted in mineral decomposition and consequent loss of hydroxyl (or water) molecules in the surface layer and even to certain depths. Determination of the hydration state of phyllosilicates typically found on asteroids as well as the relative quantities of hydrated to desiccated phyllosilicates relies on experimental data - the temperature and rate of dehydration. Both dehydration temperature and rate depend on pressure. The rate also depends on the temperature. Experimentally determined phase curves for serpentine, that show for example decomposition of antigorite to forsterite and enstatite or talc and water, exist for GPa pressure levels. For antigorite, these temperatures span the range 500-750°C for pressures between 0.1 GPa and 8 GPa. However, these data are not suitable for vacuum environment found on asteroids; further, at lower pressures, the available data suggest a monotonically decreasing dehydration temperature with decreasing pressure. Also, the available data suggest dependence of both dehydration temperature and rate on the grain size distribution of the mineral. We have determined the temperature and rate of dehydration of the serpentine polymorphs antigorite, lizardite, cronstedtite, under high vacuum conditions and for various grain size distributions. The grain size distributions have been determined by particle analyzer and each sample source was also analyzed using X-Ray Diffraction.

Petrology and geochemistry of meta-ultramafic rocks in the Paleozoic Granjeno Schist, northeastern Mexico: Remnants of Pangaea ocean floor

NASA Astrophysics Data System (ADS)

Torres-Sánchez, Sonia Alejandra; Augustsson, Carita; Jenchen, Uwe; Rafael Barboza-Gudiño, J.; Alemán Gallardo, Eduardo; Ramírez Fernández, Juan Alonso; Torres-Sánchez, Darío; Abratis, Michael

2017-08-01

The Granjeno Schist is a meta-volcanosedimentary upper Paleozoic complex in northeastern Mexico. We suggest different tectonic settings for metamorphism of its serpentinite and talc-bearing rocks based on petrographic and geochemical compositions. According to the REE ratios (LaN/YbN = 0.51 -20.0 and LaN/SmN = 0.72-9.1) and the enrichment in the highly incompatible elements Cs (0.1 ppm), U (2.8 ppm), and Zr (60 ppm) as well as depletion in Ba (1 - 15 ppm), Sr (1 -184 ppm), Pb (0.1 -14 ppm), and Ce (0.1 -1.9 ppm) the rocks have mid-ocean ridge and subduction zones characteristics. The serpentinite contains Al-chromite, ferrian chromite and magnetite. The Al-chromite is characterized by Cr# of 0.48 to 0.55 suggesting a MORB origin, and Cr# of 0.93 to 1.00 for the ferrian chromite indicates a prograde metamorphism. We propose at least two serpentinization stages of lithospheric mantle for the ultramafic rock of the Granjeno Schist, (1) a first in an ocean-floor environment at sub-greenschist to greenschist facies conditions and (2) later a serpentinization phase related to the progressive replacement of spinel by ferrian chromite and magnetite at greenschist to low amphibolite facies conditions during regional metamorphism. The second serpentinization phase took place in an active continental margin during the Pennsylvanian. We propose that the origin of the ultramafic rocks is related to an obduction and accretional event at the western margin of Pangea.

Spitzer IRS Spectroscopy of the 10 Myr-Old EF Cha Debris Disk: Evidence for Phyllosilicate-Rich Dust in the Terrestrial Zone

NASA Technical Reports Server (NTRS)

Currie, Thayne; Lisse, Carey M.; Sicillia-Aguilar, Aurora; Rieke, George H.; Su, Kate Y. L.

2011-01-01

We describe Spitzer IRS spectroscopic observations of the approx. 10 Myr-old star, EF Chao Compositional modeling of the spectra from 5 micron to 35 micron confirms that it is surrounded by a luminous debris disk with L(sub D)/L(sub *) approx. 10(exp -3), containing dust with temperatures between 225 K and 430 K characteristic of the terrestrial zone. The EF Cha spectrum shows evidence for many solid-state features, unlike most cold, low-luminosity debris disks but like some other 10-20 Myr-old luminous, warm debris disks (e.g. HD 113766A). The EF Cha debris disk is unusually rich in a species or combination of species whose emissivities resemble that of finely-powdered, laboratory-measured phyllosilicate species (talc, saponite, and smectite), which are likely produced by aqueous alteration of primordial anhydrous rocky materials. The dust and, by inference, the parent bodies of the debris also contain abundant amorphous silicates and metal sulfides, and possibly water ice. The dust's total olivine to pyroxene ratio of approx. 2 also provides evidence of aqueous alteration. The large mass volume of grains with sizes comparable to or below the radiation blow-out limit implies that planetesimals may be colliding at a rate high enough to yield the emitting dust but not so high as to devolatize the planetesimals via impact processing. Because phyllosilicates are produced by the interactions between anhydrous rock and warm, reactive water, EF Cha's disk is a likely signpost for water delivery to the terrestrial zone of a young planetary system.

Fluid-rock interactions during UHP metamorphism: A review of the Dabie-Sulu orogen, east-central China

NASA Astrophysics Data System (ADS)

Zhang, Z. M.; Shen, K.; Liou, J. G.; Dong, X.; Wang, W.; Yu, F.; Liu, F.

2011-08-01

Comprehensive review on the characteristics of petrology, oxygen isotope, fluid inclusion and nominally anhydrous minerals (NAMs) for many Dabie-Sulu ultrahigh-pressure (UHP) metamorphic rocks including drill-hole core samples reveals that fluid has played important and multiple roles during complicated fluid-rock interactions attending the subduction and exhumation of supracrustal rocks. We have identified several distinct stages of fluid-rock interactions as follows: (1) The Neoproterozoic supercrustal protoliths of UHP rocks experienced variable degrees of hydration through interactions with cold meteoric water with extremely low oxygen isotope compositions during Neoproterozoic Snow-ball Earth time. (2) A series of dehydration reactions took place during Triassic subduction of the Yangtze plate beneath the Sino-Korean plate; the released fluid entered mainly into volatile-bearing high-pressure (HP) and UHP minerals, such as phengite, zoisite-epidote, talc, lawsonite and magnesite, as well as into UHP NAMs, such as garnet, omphacite and rutile. (3) Silicate-rich supercritical fluid (hydrous melt) existed during the UHP metamorphism at mantle depths >100 km which mobilized many normally fluid-immobile elements and caused unusual element fractionation. (4) The fluid exsolved from the NAMs during the early exhumation of the Dabie-Sulu terrane was the main source for HP hydrate retrogression and generation of HP veins. (5) Local amphibolite-facies retrogression at crustal depths took place by infiltration of aqueous fluid of various salinities possibly derived from an external source. (6) The greenschist-facies overprinting and low-pressure (LP) quartz veins were generated by fluid flow along ductile shear zones and brittle faults during late-stage uplift of the UHP terrane.

Tectonic origin of serpentinites on Syros, Greece: Geochemical signatures of abyssal origin preserved in a HP/LT subduction complex

NASA Astrophysics Data System (ADS)

Cooperdock, Emily H. G.; Raia, Natalie H.; Barnes, Jaime D.; Stockli, Daniel F.; Schwarzenbach, Esther M.

2018-01-01

This study combines whole rock trace and major element geochemistry, and stable isotope (δD and δ18O) analyses with petrographic observations to deduce the origin and tectonic setting of serpentinization of ultramafic blocks from the exhumed HP/LT Aegean subduction complex on Syros, Greece. Samples are completely serpentinized and are characterized by mineral assemblages that consist of variable amounts of serpentine, talc, chlorite, and magnetite. δD and δ18O values of bulk rock serpentinite powders and chips (δD = - 64 to - 33‰ and δ18O = + 5.2 to + 9.0‰) reflect hydration by seawater at temperatures < 250 °C in an oceanic setting pre-subduction, or by fluids derived from dehydrating altered oceanic crust during subduction. Fluid-mobile elements corroborate the possibility of initial serpentinization by seawater, followed by secondary fluid-rock interactions with a sedimentary source pre- or syn-subduction. Whole rock major element, trace element, and REE analyses record limited melt extraction, exhibit flat REE patterns, and do not show pronounced Eu anomalies. The geochemical signatures preserved in these serpentinites argue against a mantle wedge source, as has been previously speculated for ultramafic rocks on Syros. Rather, the data are consistent with derivation from abyssal peridotites in a hyper-extended margin setting or mid-ocean ridge and fracture zone environment. In either case, the data suggest an extensional and/or oceanic origin associated with the Cretaceous opening of the Pindos Ocean and not a subduction-related derivation from the mantle wedge.

Changes in zinc speciation with mine tailings acidification in a semi-arid weathering environment

PubMed Central

Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon

2011-01-01

High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semi-arid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6,000 to 450 mg kg−1) and plant-available (590 to 75 mg kg−1) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and micro-focused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn0.8talc), Zn sorbed to ferrihydrite (ZnadsFeOx), and zinc sulfate (ZnSO4·7H2O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly-crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Micro-scale analyses identified hetaerolite (ZnMn2O4), hemimorphite (Zn4Si2O7(OH)2·H2O) and sphalerite (ZnS) as minor phases. Bulk and micro-focused spectroscopy complement the chemical extraction results and highlight the importance of using a multi-method approach to interrogate complex tailings systems. PMID:21761897

Workplace exposure to nanoparticles and the application of provisional nanoreference values in times of uncertain risks

NASA Astrophysics Data System (ADS)

van Broekhuizen, Pieter; van Broekhuizen, Fleur; Cornelissen, Ralf; Reijnders, Lucas

2012-03-01

Nano reference values (NRVs) for occupational use of nanomaterials were tested as provisional substitute for Occupational Exposure Limits (OELs). NRVs can be used as provisional limit values until Health-Based OELs or derived no-effect levels (DNEL) become available. NRVs were defined for 8 h periods (time weighted average) and for short-term exposure periods (15 min-time weighted average). To assess the usefulness of these NRVs, airborne number concentrations of nanoparticles (NPs) in the workplace environment were measured during paint manufacturing, electroplating, light equipment manufacturing, non-reflective glass production, production of pigment concentrates and car refinishing. Activities monitored were handling of solid engineered NPs (ENP), abrasion, spraying and heating during occupational use of nanomaterials (containing ENPs) and machining nanosurfaces. The measured concentrations are often presumed to contain ENPs as well as process-generated NPs (PGNP). The PGNP are found to be a significant source for potential exposure and cannot be ignored in risk assessment. Levels of NPs identified in workplace air were up to several millions of nanoparticles/cm3. Conventional components in paint manufacturing like CaCO3 and talc may contain a substantial amount of nanosized particulates giving rise to airborne nanoparticle concentrations. It is argued that risk assessments carried out for e.g. paint manufacturing processes using conventional non-nano components should take into account potential nanoparticle emissions as well. The concentrations measured were compared with particle-based NRVs and with mass-based values that have also been proposed for workers protection. It is concluded that NRVs can be used for risk management for handling or processing of nanomaterials at workplaces provided that the scope of NRVs is not limited to ENPs only, but extended to the exposure to process-generated NPs as well.

A Lower Temperature FDM 3D Printing for the Manufacture of Patient-Specific Immediate Release Tablets.

PubMed

Okwuosa, Tochukwu C; Stefaniak, Dominika; Arafat, Basel; Isreb, Abdullah; Wan, Ka-Wai; Alhnan, Mohamed A

2016-11-01

The fabrication of ready-to-use immediate release tablets via 3D printing provides a powerful tool to on-demand individualization of dosage form. This work aims to adapt a widely used pharmaceutical grade polymer, polyvinylpyrrolidone (PVP), for instant on-demand production of immediate release tablets via FDM 3D printing. Dipyridamole or theophylline loaded filaments were produced via processing a physical mixture of API (10%) and PVP in the presence of plasticizer through hot-melt extrusion (HME). Computer software was utilized to design a caplet-shaped tablet. The surface morphology of the printed tablet was assessed using scanning electron microscopy (SEM). The physical form of the drugs and its integrity following an FDM 3D printing were assessed using x-ray powder diffractometry (XRPD), thermal analysis and HPLC. In vitro drug release studies for all 3D printed tablets were conducted in a USP II dissolution apparatus. Bridging 3D printing process with HME in the presence of a thermostable filler, talc, enabled the fabrication of immediate release tablets at temperatures as low as 110°C. The integrity of two model drugs was maintained following HME and FDM 3D printing. XRPD indicated that a portion of the loaded theophylline remained crystalline in the tablet. The fabricated tablets demonstrated excellent mechanical properties, acceptable in-batch variability and an immediate in vitro release pattern. Combining the advantages of PVP as an impeding polymer with FDM 3D printing at low temperatures, this approach holds a potential in expanding the spectrum of drugs that could be used in FDM 3D printing for on demand manufacturing of individualised dosage forms.

Sea water - basalt interactions and genesis of the coastal thermal waters of Maharashtra, India

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muthuraman, K.

1986-01-01

The thermal waters close to the western coastal belt of India (in Maharashtra State) generally discharge Na-Ca-Cl and Ca-Na-Cl types of waters through the basic lava flows of late Cretaceous-early Tertiary age. Experimental work to study the reactions between the dilute sea water and basalt conducted in static autoclaves at selected elevated temperatures, indicates the possibility of producing chloride waters with relatively high calcium, similar to these thermal waters. In view of the increase in Ca in the resultant solutions during sea water-basalt reactions at elevated temperatures, the base temperatures computed by Na-K-Ca geothermometry would be far lower than themore » actual temperatures of the system. At lower temperatures (around 100/sup 0/C) absorption by K by basalt is possible and, hence, alkali geothermometry also may not be reliable for such systems. Anhydrite saturation temperature seems to be a reliable geothermometer for such coastal thermal water systems involving a sea water component. The results of the computer processing of the chemistry of some of these thermal waters using ''WATEQ'' are discussed. Two of these waters are oversaturated with diopside, tremolite, calcite and aragonite, indicating a rather low temperature of origin. In two other cases, interaction with ultramafic rocks is indicated, as these waters are oversaturated with diopside, tremolite, talc, chrysotile, sepiolite and its precipitate. There is no clear evidence to show that the thermal waters of the west coast of India emerge directly from either marine evaporites or oil field waters. It is proposed that the majority of these thermal waters should have originated through interaction of an admixture of sea water and meteoric water with the local basalt flows at some elevated temperatures.« less

Development and evaluation of 6-mercaptopurine and metoclopramide polypill formulation for oral administration: In-vitro and ex vivo studies

PubMed Central

Chowdhary, Rajani; Pai, Roopa S; Singh, Gurinder

2013-01-01

Introduction: The present investigation was to develop a polypill of 6-mercaptopurine and metoclopramide. A polypill with delayed release granules of an anticancer and immediate release mucoadhesive tablet of antiemetic may result in the reduction of emesis caused by oral chemotherapy. Materials and Methods: 6-Mercaptopurine granules were prepared by wet granulation process. Chitosan, hydroxypropyl methylcellulose, and ethylcellulose were used as individually as delayed release polymers. Seven granule formulations (F1-F7) were prepared and evaluated for flow properties and drug content. Immediate release mucoadhesive tablets of metoclopramide were prepared by direct compression technique using pectin and PVPK-40 as mucoadhesive polymers. Three formulations of pectin (L1-L3) and three formulations of PVPK40 (M1-M3) were prepared using lactose, magnesium stearate, and mannitol and talc as diluent and glidant, respectively. Tablets were evaluated for weight variation, hardness, friability, drug content, ex vivo mucoadhesion time, and in vitro dissolution studies. Results: Formulation F2, F4, F5, and F7 showed maximum drug content. Formulation F7 exhibited the drug release up to 2 h and was selected as the best delayed release formulation. All formulations of metoclopramide showed good drug content ranging from 97.6 % to 100.6%. Formulation M2 among tablets prepared with PVP exhibited desired mucoadhesion time of 15.33 min which prolongs the duration of drug release in gastric pouch of the male Wistar rats. Both the selected formulations F7 and M2 were filled into body of capsule size 0 and capsule was evaluated for technological properties. Conclusion: It may be concluded that polypill released the metoclopramide immediately prior to 6-mercaptopurine. PMID:24350042

Deformation and Metasomatic Evolution at the Subduction Plate Interface As Viewed from Study of HP/UHP Metamorphic Rocks

NASA Astrophysics Data System (ADS)

Bebout, G. E.; Penniston-Dorland, S.

2014-12-01

We provide a view of lithologic makeup, deformation, and fluid-rock interaction along the deep forearc to subarc plate interface, based on insights gained from study of HP/UHP metamorphic rocks. Exposures of plate-boundary shear zones on which we base our perspective represent 30-80 km depths and are on Catalina Island and at Monviso, Syros, and New Caledonia. Each contains highly deformed zones with schistose matrix, commonly with a large ultramafic component, containing bodies of less deformed mafic, sedimentary, and ultramafic rocks. These "blocks" have varying geometries, are up to km-scale, and can preserve disparate P-T histories reflecting dynamics of incorporation and entrainment. Sheared matrices contain high-variance, hydrous mineral assemblages in some cases resembling metasomatic zones ("rinds") at block-matrix contacts, and rinds and matrices have homogenized isotopic compositions reflecting extensive fluid-rock interaction. Shearing and related physical juxtaposition of disparate metasomatic rocks can result in mixed or 'hybrid' chemical compositions. The chlorite-, talc-, and amphibole-rich schists developed by these processes can stabilize H2O to great depth and influence its cycling. Fluids (hydrous fluids, silicate melts) released within slabs necessarily interact with highly deformed, lithologically hybridized zones at the plate interface as they ascend to potentially enter mantle wedges. Fluids bearing chemical/isotopic signatures of hybrid rocks appear capable of producing arc magma compositions interpreted as reflecting multiple, chemically distinct fluids sources. Geophysical signatures of these rheologically weak zones are equivocal but many recognize the presence of zones of low seismic velocity at/near the top of slabs and attribute them to hydrated rocks. Whether rocks from this interface buoyantly ascend into mantle wedges, indicated in some theoretical models, remains largely untested by field and geophysical observations.

Constraints on the stress state of the San Andreas Fault with analysis based on core and cuttings from San Andreas Fault Observatory at Depth (SAFOD) drilling phases 1 and 2

USGS Publications Warehouse

Tembe, S.; Lockner, D.; Wong, T.-F.

2009-01-01

Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (?? 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature-and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (?????0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress. Copyright 2009 by the American Geophysical Union.

Detection of ionizing radiations by studying ceramic tiles materials using thermoluminescence technique

NASA Astrophysics Data System (ADS)

Mandavia, H. C.; Murthy, K. V. R.; Purohit, R. U.

2017-05-01

Natural background radiation comes from two primary sources: cosmic radiation and terrestrial sources. Our natural environment has both livings and non-livings like - Sun, Moon, Sky, Air, Water, Soil, Rivers, Mountains, Forests, besides plants and animals. The worldwide average background dose for a human being is about 2.4 millisievert (mSv) per year. This exposure is mostly from cosmic radiation and natural radionuclides in the environment. The Earth, and all living things on it, are constantly bombarded by radiation from outer space. This radiation primarily consists of positively charged ions from protons to iron and larger nuclei derived sources outside our solar system. This radiation interacts with atoms in the atmosphere to create secondary radiation, including X-rays, muons, protons, alpha particles, pions, electrons, and neutrons. The present study discusses the utility of ceramic tiles as radiation dosimeters in case of nuclear fallout. Many flooring materials most of them are in natural form are used to manufacture floor tiles for household flooring purpose. Many natural minerals are used as the raw materials required for the manufacturing ceramic ware. The following minerals are used to manufacturing the ceramic tiles i.e. Quartz, Feldspar, Zircon, Talc, Grog, Alumina oxide, etc. Most of the minerals are from Indian mines of Gujarat and Rajasthan states, some of are imported from Russian subcontinent. The present paper reports the thermoluminescence dosimetry Study of Feldspar and Quartz minerals collected from the ceramic tiles manufacturing unit, Morbi. The main basis in the Thermoluminescence Dosimetry (TLD) is that TL output is directly proportional to the radiation dose received by the phosphor and hence provides the means of estimating unknown radiations from environment.

AB 66. One-year experience of the pulmonary department of Aristotle University of Thessaloniki in thoracoscopy with local anaesthesia (medical thoracoscopy)

PubMed Central

Spyropoulos, George; Kontakiotis, Theodoros; Spyratos, Dionysios; Iakovidis, Dimitrios; Zoglopitis, Fotis; Zarogoulidis, Konstantinos

2012-01-01

Background Thoracoscopy with local anesthesia or medical thoracoscopy is an invasive method which is rather valuable not only for the approach of undiagnosed exudative pleural effusions but also for the treatment of symptomatic malignant effusions with the conduct of pleurodesis. This is a review of those patients who underwent medical thoracoscopy in the period May 2011 to September 2012 in the Pulmonary Department the Aristotle University of Thessaloniki. Patients and methods Thirty nine thoracoscopies were conducted in our Department since May 2011. Twenty nine patients with cytological test negative for malignancy underwent diagnostic thoracoscopy. Eleven of those procedures were diagnostic and positive for malignancy, while 12 were non-diagnostic and 2 with limited evidence of malignancy. The biopsy results of 2 thoracoscopies showed granulomatous infection and other 2 nonspecific chronic inflammation. Out of all the diagnoses which were positive for malignancy, 2 were related to mesothelioma, 5 to adenocarcinoma (4 of them originated from lungs and one of unknown primary origin) while 1 patient was diagnosed with metastatic papillary adenocarcinoma originated from the thyroid and another one with lymphoma. There were also patients carrying diagnosed illness intending pleurodesis in cases of malignant recrudescent pleural effusions in mesothelioma, lung adenocarcinoma and biliary carcinoma who underwent thoracoscopy. Another patient with recrudescent pneumothorax underwent pleurodesis with talc. Results The major complications which emerged either during the procedure or after the thoracoscopy were two: one patient developed allergy in lidocaine intake for the local anesthesia having as a result to quit the procedure while another patient developed an empyema several weeks later. Conclusions Thoracoscopy with local anesthesia is a safe procedure, tolerable for the patient, which has a significant diagnostic value and only a small percentage of complications.

Interstitial Lung Disease after Pleurodesis for Malignant Pleural Effusion

PubMed Central

Yokoe, Norihito; Katsuda, Eisuke; Kosaka, Kenshi; Hamanaka, Rie; Matsubara, Ayako; Nishimura, Masaki; Tanaka, Hiroyuki; Asai, Nobuhiro; Takahashi, Ayumu; Kawamura, Toshiki; Ishiguchi, Tsuneo; Yamaguchi, Etsuro; Kubo, Akihito

2017-01-01

Objective Pleurodesis is an effective therapy for malignant pleural effusion (MPE). While interstitial lung disease (ILD) has been regarded as a serious complication of pleurodesis, its clinicopathological characteristics have not been fully understood. This study was conducted to elucidate the incidence of ILD and the risk factors for ILD in patients who underwent pleurodesis to control MPE. Methods The medical records of patients who underwent pleurodesis in Aichi Medical University between March 2008 and February 2013, the period before the approval of talc in Japan, were retrospectively analyzed. Results A total of 84 patients underwent pleurodesis, all using OK-432. ILD occurred in 13 patients (15.5%). The development of ILD after pleurodesis was significantly associated with old age (odds ratio [OR]: 4.82, 95% confidence interval [CI]: 1.22-19.08) and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment (OR: 5.97, CI: 1.7-20.9). A multivariate analysis revealed that >67 years of age (p=0.01) and EGFR-TKI treatment (p=0.02) were significantly associated with the development of pleurodesis-related ILD. Among the patients who received both pleurodesis and EGFR-TKIs (n=23), 8 patients developed ILD. All of these patients were receiving EGFR-TKI therapy at the time of pleurodesis or within 30 days after pleurodesis. In contrast, no cases of ILD were observed among the patients who stopped EGFR-TKIs before pleurodesis or started EGFR-TKIs at more than 30 days after pleurodesis. Conclusion ILD seemed to be a frequent complication of pleurodesis in patients using OK-432, especially elderly patients and those who underwent pleurodesis while receiving EGFR-TKI therapy or who started EGFR-TKI therapy within 30 days after pleurodesis. PMID:28717073

Interstitial Lung Disease after Pleurodesis for Malignant Pleural Effusion.

PubMed

Yokoe, Norihito; Katsuda, Eisuke; Kosaka, Kenshi; Hamanaka, Rie; Matsubara, Ayako; Nishimura, Masaki; Tanaka, Hiroyuki; Asai, Nobuhiro; Takahashi, Ayumu; Kawamura, Toshiki; Ishiguchi, Tsuneo; Yamaguchi, Etsuro; Kubo, Akihito

2017-01-01

Objective Pleurodesis is an effective therapy for malignant pleural effusion (MPE). While interstitial lung disease (ILD) has been regarded as a serious complication of pleurodesis, its clinicopathological characteristics have not been fully understood. This study was conducted to elucidate the incidence of ILD and the risk factors for ILD in patients who underwent pleurodesis to control MPE. Methods The medical records of patients who underwent pleurodesis in Aichi Medical University between March 2008 and February 2013, the period before the approval of talc in Japan, were retrospectively analyzed. Results A total of 84 patients underwent pleurodesis, all using OK-432. ILD occurred in 13 patients (15.5%). The development of ILD after pleurodesis was significantly associated with old age (odds ratio [OR]: 4.82, 95% confidence interval [CI]: 1.22-19.08) and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment (OR: 5.97, CI: 1.7-20.9). A multivariate analysis revealed that >67 years of age (p=0.01) and EGFR-TKI treatment (p=0.02) were significantly associated with the development of pleurodesis-related ILD. Among the patients who received both pleurodesis and EGFR-TKIs (n=23), 8 patients developed ILD. All of these patients were receiving EGFR-TKI therapy at the time of pleurodesis or within 30 days after pleurodesis. In contrast, no cases of ILD were observed among the patients who stopped EGFR-TKIs before pleurodesis or started EGFR-TKIs at more than 30 days after pleurodesis. Conclusion ILD seemed to be a frequent complication of pleurodesis in patients using OK-432, especially elderly patients and those who underwent pleurodesis while receiving EGFR-TKI therapy or who started EGFR-TKI therapy within 30 days after pleurodesis.

Changes in zinc speciation with mine tailings acidification in a semiarid weathering environment.

PubMed

Hayes, Sarah M; O'Day, Peggy A; Webb, Sam M; Maier, Raina M; Chorover, Jon

2011-09-01

High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semiarid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6000 to 450 mg kg(-1)) and plant-available (590 to 75 mg kg(-1)) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and microfocused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn(0.8)talc), Zn sorbed to ferrihydrite (Zn(adsFeOx)), and zinc sulfate (ZnSO(4) · 7H(2)O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Microscale analyses identified hetaerolite (ZnMn(2)O(4)), hemimorphite (Zn(4)Si(2)O(7)(OH)(2) · H(2)O) and sphalerite (ZnS) as minor phases. Bulk and microfocused spectroscopy complement the chemical extraction results and highlight the importance of using a multimethod approach to interrogate complex tailings systems.

Komatiites and nickel sulfide ores of the Black Swan area, Yilgarn Craton, Western Australia. 4. Platinum group element distribution in the ores, and genetic implications

NASA Astrophysics Data System (ADS)

Barnes, Stephen J.

2004-11-01

The Black Swan komatiite sequence, in the Eastern Goldfields province of the Archaean Yilgarn Craton in Western Australia, is a body of dominantly olivine-rich cumulates with lesser volumes of spinifex textured rocks, interpreted as a section through an extensive komatiite lava flow field. The sequence hosts a number of nickel sulfide orebodies, including the Silver Swan massive shoot and the Cygnet and Black Swan disseminated orebodies. The massive sulfide orebodies of the Black Swan Succession are pervasively depleted in all platinum group elements (PGEs), particularly Pt and Pd, despite very high Ni contents. This depletion cannot be explained by R-factor variations, which would also require relatively low Ni tenors. The PGE depletion could be explained in part if the ores are enriched in a monosulfide solid solution (MSS) cumulate component, but requires some additional fractional segregation of sulfide melt upstream from the site of deposition. The Silver Swan orebody shows a remarkably consistent vertical zonation in PGE contents, particularly in Ir, Ru, Rh, Os, which increase systematically from very low levels at the stratigraphic base of the sulfide body to maxima corresponding roughly with the top of a lower layer of the orebody rich in silicate inclusions. Platinum shows the opposite trend, but is somewhat modified by remobilisation during talc carbonate alteration. A similar pattern is also observed in the adjacent White Swan orebody. This zonation is interpreted and modelled as the result of fractional crystallisation of MSS from the molten sulfide pool. The strong IPGE depletion towards the base of the orebody may be a consequence of sulfide liquid crystallisation in an inverted thermal gradient, between a thin rapidly cooling upper rind of komatiite lava and a hot substrate.

Intermediate-Depth Subduction Earthquakes Recorded by Pseudotachylyte in Dry Eclogite-Facies Oceanic Lithosphere from the Alps

NASA Astrophysics Data System (ADS)

Scambelluri, M.; Pennacchioni, G.; Gilio, M.; Bestmann, M.

2016-12-01

While geophysical studies and laboratory experiments provide much information on subduction earthquakes, field studies identifying the rock types for earthquake development and the deep seismogenic environments are still scarce. To date, fluid overpressure and volume decrease during hydrous mineral breakdown the widely favoured trigger of subduction earthquakes in serpentinized lithospheric mantle and hydrated low-velocity layers atop slabs. Here we document up to 40 cm-thick pseudotachylyte (PST) in Alpine oceanic gabbro and peridotite (2-2.5 GPa-550-620°C), the analogue of a modern cold subducting oceanic lithosphere. These rocks mostly remained unaltered dry systems; only very minor domains (<1%) record partial hydration and static eclogitic metamorphism. Meta-peridotite shows high-pressure olivine + antigorite (garnet + zoisite + chlorite after mantle plagioclase); meta-gabbro develops omphacite + zoisite + talc + chloritoid + garnet. Abundant syn-eclogitic pseudotachylyte cut the dry gabbro-peridotite and the eclogitized domains. In meta-peridotite, PST shows olivine, orthopyroxene, spinel microliths and clasts of high-pressure olivine + antigorite and garnet + zoisite + chlorite aggregates. In metagabbro, microfaults in damage zones near PST cut brecciated igneous pyroxene cemented by omphacite. In unaltered gabbro, glassy PST contains micron-scale garnet replacing plagioclase microliths during, or soon after, PST cooling. In the host rock, garnet coronas between igneous olivine and plagioclase only occur near PST and between closely spaced PST veins. Absence of garnet away from PST indicates that garnet growth was triggered by mineral seeds and by heat released by PST. The above evidence shows that pseudotachylyte formed at eclogite-facies conditions. In such setting, strong, dry, metastable gabbro-peridotite concentrate stress to generate large intermediate depth subduction earthquakes without much involvement of free fluid.

Control of Fusarium verticillioides, cause of ear rot of maize, by Pseudomonas fluorescens.

PubMed

Nayaka, Siddaiah Chandra; Shankar, Arakere C Udaya; Reddy, Munagala S; Niranjana, Siddapura R; Prakash, Harishchandra S; Shetty, Hunthrike S; Mortensen, Carmen N

2009-07-01

Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have elicited considerable attention over the past decade owing to their association with animal disease syndromes. Hence, the present study was conducted to evaluate ecofriendly approaches by using a maize rhizosphere isolate of Pseudomonas fluorescens (Trev.) Mig. and its formulation to control ear rot disease and fumonisin accumulation, and also to study the capacity to promote growth and yield of maize. In vitro assays were conducted to test the efficacy of P. fluorescens as a seed treatment on seed germination, seedling vigour and also the incidence of F. verticillioides in different maize cultivars. The field trials included both seed treatment and foliar spray. For all the experiments, P. fluorescens was formulated using corn starch, wheat bran and talc powder. In each case there were three different treatments of P. fluorescens, a non-treated control and chemical control. Pure culture and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F. verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize kernels intended for human and animal feed. (c) 2009 Society of Chemical Industry.

[Near infrared spectrum analysis and meaning of the soil in 512 earthquake surface rupture zone in Pingtong, Sichuan].

PubMed

Yi, Ze-bang; Cao, Jian-jin; Luo, Song-ying; Wang, Zheng-yang; Liao, Yi-peng

2014-08-01

Through modern near infrared spectrum, the authors analyzed the yellow soil from the rupture zone located in Ping- tong town,Pingwu, Sichuan province. By rapid identification of the characteristic of peak absorption of mineral particles, the result shows that the soil samples mainly composed of calcite, dolomite, muscovite, sericite, illite, smectite; talc, tremolite, actinolite, chlorite, etc. And the mineral compositions of the soil is basically the same with the yellow soil in Sichuan region. By analyzing and comparing it was revealed that part of mineral compositions of the soil are in accordance with the characteristics of the rock mineral compositions below the rupture zone, indicating that part of the minerals of the soil's evolution is closely related to the rock compositions in this area; and the compositions of the clay mineral in the rupture zone is similar to the Ma Lan loess in the north of China, so it is presumed that the clay minerals in these two kinds of soil have the same genetic type. The characteristic of the mineral composition of the soil is in accordance with evolution characteristics of the rocks which is bellow the rupture zone, also it was demonstrated that the results of soil minerals near-infrared analysis can effectively analyze the mineral particles in the soil and indicate the pedogenic environment. Therefore, the result shows the feasibility of adopting modern near-infrared spectrum for rapid analysis of mineral particles of the soil and research of geology. Meanwhile, the results can be the foundation of this region's soil mineral analysis, and also provide new ideas and methods for the future research of soil minerals and the earthquake rupture zone.

Constraints on the stress state of the San Andreas fault with analysis based on core and cuttings from SAFOD drilling phases I and II

USGS Publications Warehouse

Lockner, David A.; Tembe, Cheryl; Wong, Teng-fong

2009-01-01

Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (m < 0.2) or strength consistent with standard laboratory tests (m > 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature- and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (m0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress.

Video-assisted thoracoscopic surgery using single-lumen endotracheal tube anesthesia.

PubMed

Cerfolio, Robert James; Bryant, Ayesha S; Sheils, Todd M; Bass, Cynthia S; Bartolucci, Alfred A

2004-07-01

Most general thoracic surgeons use double-lumen endotracheal tube (DLET) anesthesia for all video-assisted thoracoscopic surgery (VATS). We evaluated a single-lumen endotracheal tube (SLET) for VATS for drainage of pleural effusions and pleural biopsies. A consecutive series of patients with recurrent pleural effusions underwent VATS using an SLET and only one incision. Operations were accomplished via one 2-cm incision using a 5-mm rigid thoracoscope and mediastinoscopic biopsy forceps for directed pleural biopsies. A working area was accomplished with low tidal volumes. There were 376 patients (191 women). The indications for VATS were a nondiagnosed or benign pleural effusion in 294 patients, and a malignant effusion in 82 patients. Two hundred eight patients underwent biopsy of the parietal pleura, and mean operative time was 17 min. Adequate visibility was obtained in all. When compared to preoperative cytology, VATS was more sensitive (45% compared to 99%, p < 0.001), had a higher negative predictive value (56% compared to 99%, p < 0.001), and was more accurate (67% compared to 99%, p < 0.001). Forty-seven percent of patients with a history of cancer had false-negative preoperative cytology results. Complications occurred in seven patients (2%), and there were three operative deaths (none related to the operative procedure). VATS using SLET and only one incision is possible, and it affords excellent visualization of the pleural space, allowing pleural biopsies and talc insufflation. It avoids the risk, time, and cost of a DLET. It is significantly more sensitive and accurate than preoperative cytology, and it should be considered as the diagnostic and therapeutic procedure of choice in patients with recurrent pleural effusions.

South-verging early folds: An important element in the structure of the northern Green Mountains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, P.J.

1993-03-01

Reconnaissance mapping in the Camels Hump Group, Mt. Mansfield 7.5[prime] quadrangle, north-central Vermont, indicates more complex structures than those portrayed on previously published maps. Preliminary interpretation for the structure around Smugglers Notch, for example, is that an early recumbent syncline with Hazens Notch Formation in its center (including the Sterling Pond talc deposits), opens to the south. The early syncline is deformed by the north-northeast trending Green Mountain anticlinorium, which at Smugglers Notch plunges gently south. Thus the mass of Underhill Formation along the summit ridge of Mt. Mansfield is on the upper, overturned limb of the early fold, andmore » on the west limb of the open, upright anticlinorium. The lowest cliffs in Smugglers Notch are Underhill Formation on the upright limb of the early fold. Rocks of the intervening, intensely weathered and graphitic Hazens Notch Formation are especially prone to the rock slides for which Smugglers Notch is infamous. Early minor isoclinal folds and strongly developed quartz rods and lineations trend roughly east-west. Correlation of this fabric with east-west lineations and poorly preserved fold hinges in the Camels Hump area farther south will help correlate deformational sequences between the two areas. Early minor folds that are roughly coaxial with younger Green Mountain folds are much less common in the Mt. Mansfield area than to the south, and faulting seems to have been much less intense. Thus following marker horizons such as quartzite beds and greenstones around fold hinges may be more successful. Do south-directed structures indicate lateral movement of material toward the Vermont reentrant during the Taconian orogeny« less

Chemical controls on fault behavior: weakening of serpentinite sheared against quartz-bearing rocks and its significance for fault creep in the San Andreas system

USGS Publications Warehouse

Moore, Diane E.; Lockner, David A.

2013-01-01

The serpentinized ultramafic rocks found in many plate-tectonic settings commonly are juxtaposed against crustal rocks along faults, and the chemical contrast between the rock types potentially could influence the mechanical behavior of such faults. To investigate this possibility, we conducted triaxial experiments under hydrothermal conditions (200-350°C), shearing serpentinite gouge between forcing blocks of granite or quartzite. In an ultramafic chemical environment, the coefficient of friction, µ, of lizardite and antigorite serpentinite is 0.5-0.6, and µ increases with increasing temperature over the tested range. However, when either lizardite or antigorite serpentinite is sheared against granite or quartzite, strength is reduced to µ ~ 0.3, with the greatest strength reductions at the highest temperatures (temperature weakening) and slowest shearing rates (velocity strengthening). The weakening is attributed to a solution-transfer process that is promoted by the enhanced solubility of serpentine in pore fluids whose chemistry has been modified by interaction with the quartzose wall rocks. The operation of this process will promote aseismic slip (creep) along serpentinite-bearing crustal faults at otherwise seismogenic depths. During short-term experiments serpentine minerals reprecipitate in low-stress areas, whereas in longer experiments new Mg-rich phyllosilicates crystallize in response to metasomatic exchanges across the serpentinite-crustal rock contact. Long-term shear of serpentinite against crustal rocks will cause the metasomatic mineral assemblages, which may include extremely weak minerals such as saponite or talc, to play an increasingly important role in the mechanical behavior of the fault. Our results may explain the distribution of creep on faults in the San Andreas system.

Role of cellulose ether polymers on ibuprofen release from matrix tablets.

PubMed

Vueba, M L; Batista de Carvalho, L A E; Veiga, F; Sousa, J J; Pina, Maria Eugénia

2005-08-01

Cellulose derivatives are the most frequently used polymers in formulations of pharmaceutical products for controlled drug delivery. The main aim of the present work was to evaluate the effect of different cellulose substitutions on the release rate of ibuprofen (IBP) from hydrophilic matrix tablets. Thus, the release mechanism of IBP with methylcellulose (MC25), hydroxypropylcellulose (HPC), and hydroxypropylmethylcellulose (HPMC K15M or K100M) was studied. In addition, the influence of the diluents lactose monohydrate (LAC) and beta-cyclodextrin (beta-CD) was evaluated. Distinct test formulations were prepared containing: 57.14% of IBP, 20.00% of polymer, 20.29% of diluent, 1.71% of talc lubricants, and 0.86% of magnesium stearate as lubricants. Although non-negligible drug-excipient interactions were detected from DSC studies, these were found not to constitute an incompatibility effect. Tablets were examined for their drug content, weight uniformity, hardness, thickness, tensile strength, friability, porosity, swelling, and dissolution performance. Polymers MC25 and HPC were found to be unsuitable for the preparation of this kind of solid dosage form, while HPMC K15M and K100M showed to be advantageous. Dissolution parameters such as the area under the dissolution curve (AUC), the dissolution efficiency (DE(20 h)), dissolution time (t 50%), and mean dissolution time (MDT) were calculated for all the formulations, and the highest MDT values were obtained with HPMC indicating that a higher value of MDT signifies a higher drug retarding ability of the polymer and vice-versa. The analysis of the drug release data was performed in the light of distinct kinetic mathematical models-Kosmeyer-Peppas, Higuchi, zero-, and first-order. The release process was also found to be slightly influenced by the kind of diluent used.

Energetic features of copper and lead sorption by innovative aminoalcohol-functionalized cobalt phyllosilicates.

PubMed

Melo, Maurício Alves; Airoldi, Claudio

2010-11-14

Inorganic-organic cobalt phyllosilicate hybrids were synthesized by the sol-gel procedure under mild non-hydrothermal conditions with a silicon precursor, formed through individual reactions between the silane 3-glycidoxypropyltriethoxysilane and the aminoalcohols ethanol- or diethanolamine. These procedures generated talc-like phyllosilicates containing pendant organic chains with nitrogen and oxygen basic centres located in the interlamellar region. For organofunctionalized phyllosilicates the lamellar structure obtained through the sol-gel method was confirmed by X-ray powder diffraction, while elemental analysis indicated that the densities of the organic groups attached to the new matrices were 3.31 ± 0.05 and 3.08 ± 0.07 mmol g(-1) for hybrids functionalized with ethanol- and diethanolamines, respectively. Infrared spectroscopy and nuclear magnetic resonance in the solid state for (13)C and (29)Si showed that the organic groups are indeed covalently bonded to the inorganic structures and the process of functionalization did not affect the original structures of the silylating agents employed. The thermally stable hybrids presented well-formed particles with a homogeneous distribution of cobalt and nitrogen atoms. Their abilities for copper removal from aqueous solutions gave maximum capacities of sorption of 2.01 ± 0.11 and 2.55 ± 0.15 mmol g(-1) for phyllosilicates containing ethanol- and diethanolamine groups, respectively. For lead sorption the values of 2.59 ± 0.11 and 2.43 ± 0.12 mmol g(-1) were found for this same sequence. These sorption data were adjusted to the non-linear regression of the Langmuir equation. Energetic features related to the interactions between the cations and the pendant basic centres were determined through calorimetric titrations. The acid-basic interactions reflect the spontaneity of the reactions, which are also enthalpically and entropically favourable for these chelating processes at the solid-liquid interface.

Lab Experiments Probe Interactions Between Dilute Pyroclastic Density Currents and 3D Barriers

NASA Astrophysics Data System (ADS)

Fauria, K.; Andrews, B. J.; Manga, M.

2014-12-01

We conducted scaled laboratory experiments of unconfined dilute pyroclastic density currents (PDCs) to examine interactions between three - dimensional obstacles and dilute PDCs. While it is known that PDCs can surmount barriers by converting kinetic energy into potential energy, the signature of topography on PDC dynamics is unclear. To examine the interplay between PDCs and topography, we turbulently suspended heated and ambient-temperature 20 μm talc powder in air within an 8.5 x 6.1 x 2.6 m tank. Experimental parameters (Froude number, densimetric and thermal Richardson number, particle Stokes and Settling numbers) were scaled such that the experimental currents were dynamically similar to natural PCS. The Reynolds number, however, is much smaller than in natural currents, but still large enough for the flows to be turbulent. We placed cylindrical and ridge-like objects in the path of the currents, illuminated the currents with orthogonal laser sheets, and recorded each experiment with high definition cameras. We observed currents surmounting ridge-like barriers (barrier height = current height). Slanted ridges redirected the currents upward and parallel to the upstream face of the ridges (~45° from horizontal). Down stream of the slanted ridges, ambient-temperature currents reattached to the floor. By comparison, hot currents reversed buoyancy and lifted off. These observations suggest that obstacles enhance air entrainment, a process key to affecting runout distance and the depletion of fine particles in ignimbrites. Moreover, we observed vortex shedding in the wake of cylinders. Our experiments demonstrate that barriers of various shapes affect PDC dynamics and can shorten PDC runout distances. Understanding the effects of topography on PDCs is required for interpreting many deposits because processes such as vortex shedding and topographically-induced changes in turbulent length scales and entrainment likely leave depositional signatures.

Visible Wavelength Spectroscopy of Ferric Minerals: A Key Tool for Identification of Ancient Martian Aqueous Environments

NASA Technical Reports Server (NTRS)

Murchie, Scott L.; Bell, J. F., III; Morris, Richard V.

2000-01-01

The mineralogic signatures of past aqueous alteration of a basaltic Martian crust may include iron oxides and oxyhydroxides, zeolites, carbonates, phyllosilicates, and silica. The identities, relative abundances, and crystallinities of the phases formed in a particular environment depend on physicochemical conditions. At one extreme, hot spring environments may be characterized by smectite-chlorite to talc-kaolinite silicate assemblages, plus crystalline ferric oxides dominated by hematite. However, most environments, including cold springs, pedogenic layers, and ponded surface water, are expected to deposit iron oxides and oxyhydroxides, carbonates, and smectite-dominated phyllosilicates. A substantial fraction of the ferric iron is expected to occur in nanophase form, with the exact mineralogy strongly influenced by Eh-pH conditions. Detection of these phases has been an objective of a large body of terrestrial telescopic, Mars orbital, and landed spectral investigations and in situ compositional measurements. However, clear identifications of many of these phases is lacking. Neither carbonate nor silica has been unequivocally detected by any method. Although phyllosilicates may occur near the limit of detection by remote sensing, in general they appear to occur in only poorly crystalline form. In contrast, compelling evidence for ferric iron minerals has been gathered by recent telescopic investigations, the Imager for Mars Pathfinder (IMP), and the Thermal Emission Spectrometer (TES) on the Mars Global Surveyor (MGS). These data yield two crucial findings: (1) In the global, high spatial resolution TES data set, highly crystalline ferric iron (as coarse-grained 'gray' hematite) has been recognized but with only very limited spatial occurrence and (2) Low-resolution telescopic reflectance spectroscopy, very limited orbital reflectance spectroscopy, and landed multispectral imaging provide strong indications that at least two broad classes of ferric iron minerals are commonplace in non-dust covered regions.

The Lost City Hydrothermal Field: A Spectroscopic and Astrobiological Analogue for Nili Fossae, Mars.

PubMed

Amador, Elena S; Bandfield, Joshua L; Brazelton, William J; Kelley, Deborah

2017-11-01

Low-temperature serpentinization is a critical process with respect to Earth's habitability and the Solar System. Exothermic serpentinization reactions commonly produce hydrogen as a direct by-product and typically produce short-chained organic compounds indirectly. Here, we present the spectral and mineralogical variability in rocks from the serpentine-driven Lost City Hydrothermal Field on Earth and the olivine-rich region of Nili Fossae on Mars. Near- and thermal-infrared spectral measurements were made from a suite of Lost City rocks at wavelengths similar to those for instruments collecting measurements of the martian surface. Results from Lost City show a spectrally distinguishable suite of Mg-rich serpentine, Ca carbonates, talc, and amphibole minerals. Aggregated detections of low-grade metamorphic minerals in rocks from Nili Fossae were mapped and yielded a previously undetected serpentine exposure in the region. Direct comparison of the two spectral suites indicates similar mineralogy at both Lost City and in the Noachian (4-3.7 Ga) bedrock of Nili Fossae, Mars. Based on mapping of these spectral phases, the implied mineralogical suite appears to be extensive across the region. These results suggest that serpentinization was once an active process, indicating that water and energy sources were available, as well as a means for prebiotic chemistry during a time period when life was first emerging on Earth. Although the mineralogical assemblages identified on Mars are unlikely to be directly analogous to rocks that underlie the Lost City Hydrothermal Field, related geochemical processes (and associated sources of biologically accessible energy) were once present in the subsurface, making Nili Fossae a compelling candidate for a once-habitable environment on Mars. Key Words: Mars-Habitability-Serpentinization-Analogue. Astrobiology 17, 1138-1160.

The Lost City Hydrothermal Field: A Spectroscopic and Astrobiological Analogue for Nili Fossae, Mars

NASA Astrophysics Data System (ADS)

Amador, Elena S.; Bandfield, Joshua L.; Brazelton, William J.; Kelley, Deborah

2017-11-01

Low-temperature serpentinization is a critical process with respect to Earth's habitability and the Solar System. Exothermic serpentinization reactions commonly produce hydrogen as a direct by-product and typically produce short-chained organic compounds indirectly. Here, we present the spectral and mineralogical variability in rocks from the serpentine-driven Lost City Hydrothermal Field on Earth and the olivine-rich region of Nili Fossae on Mars. Near- and thermal-infrared spectral measurements were made from a suite of Lost City rocks at wavelengths similar to those for instruments collecting measurements of the martian surface. Results from Lost City show a spectrally distinguishable suite of Mg-rich serpentine, Ca carbonates, talc, and amphibole minerals. Aggregated detections of low-grade metamorphic minerals in rocks from Nili Fossae were mapped and yielded a previously undetected serpentine exposure in the region. Direct comparison of the two spectral suites indicates similar mineralogy at both Lost City and in the Noachian (4-3.7 Ga) bedrock of Nili Fossae, Mars. Based on mapping of these spectral phases, the implied mineralogical suite appears to be extensive across the region. These results suggest that serpentinization was once an active process, indicating that water and energy sources were available, as well as a means for prebiotic chemistry during a time period when life was first emerging on Earth. Although the mineralogical assemblages identified on Mars are unlikely to be directly analogous to rocks that underlie the Lost City Hydrothermal Field, related geochemical processes (and associated sources of biologically accessible energy) were once present in the subsurface, making Nili Fossae a compelling candidate for a once-habitable environment on Mars.

Listvenite logging on D/V CHIKYU: Hole BT1B, Oman Drilling Project

NASA Astrophysics Data System (ADS)

Kelemen, P. B.; Beinlich, A.; Morishita, T.; Greenberger, R. N.; Johnson, K. T. M.; Lafay, R.; Michibayashi, K.; Harris, M.; Phase I Science Party, T. O. D. P.

2017-12-01

Listvenite, quartz-carbonate altered ultramafic rock containing minor fuchsite (Cr-muscovite) forms by complete carbonation of peridotite and is thus an attractive objective for carbon mitigation studies. However, reaction controls and evolution of listvenite are still enigmatic. Here we present the first results of Phase 1 of the ICDP (International Continental Drilling Program) Oman Drilling Project and subsequent core logging using the analytical facilities on board the research vessel D/V CHIKYU. Hole BT1B contains 300 m of continuous drill core intersecting alluvium, listvenite-altered serpentinite, serpentinite, ophicarbonate and the underlying metamorphic sole of the Semail ophiolite, Oman. The drill core has been systematically investigated by visual core description, thin section petrography, X-ray fluorescence core logging, X-ray diffractometry, visible-shortwave infrared imaging spectroscopy and X-ray Computer Tomography. Our observations show that listvenite is highly variable in texture and color on the mm to m scale. Listvenite was visually categorized into 5 principal color groups: the dominant dark red (47 %), light red (19 %), orange (14 %), pale (2 %) and green (16 %). The presence of hematite/goethite results in dark reddish, red and orange hues. Light grey or pale colored listvenite lacks hematite and/or goethite veins and may represent the `true' listvenite. Green listvenite is characterized by the presence of cm-sized quartz-fuchsite intergrowths. Five zones of serpentinite, which vary in thickness between several tens of cm and 4 m, are intercalated within the massive listvenite of Hole BT1B. Gradational listvenite-serpentinite transition zones contain the ophicarbonate assemblage (magnesite + serpentine) and sometimes additional talc, representing intermediate carbonation reaction progress. Preservation of the former mesh texture and bastite after orthopyroxene in the listvenite suggest that the listvenite precursor had already been serpentinized prior to infiltration of the CO2-bearing alteration fluid.

Fluid circulations in response to mantle exhumation at the passive margin setting in the north Pyrenean zone, France

NASA Astrophysics Data System (ADS)

Corre, B.; Boulvais, P.; Boiron, M. C.; Lagabrielle, Y.; Marasi, L.; Clerc, C.

2018-02-01

Sub-continental lithospheric mantle rocks are exhumed in the distal part of magma-poor passive margins. Remnants of the North Iberian paleo-passive margin are now exposed in the North-Pyrenean Zone (NPZ) and offers a field analogue to study the processes of continental crust thinning, subcontinental mantle exhumation and associated fluid circulations. The Saraillé Massif which belongs to the `Chaînons Béarnais' range (Western Pyrenees), displays field, petrographic and stable isotopic evidence of syn-kinematic fluid circulations. Using electron probe micro-analyses on minerals, O, C, Sr isotopes compositions and micro thermometry/Raman spectrometry of fluid inclusions, we investigate the history of fluid circulations along and in the surroundings of the Saraillé detachment fault. The tectonic interface between the pre-rift Mesozoic sedimentary cover and the mantle rocks is marked by a metasomatic talc-chlorite layer. This layer formed through the infiltration of a fluid enriched in chemical elements like Cr leached from the exhuming serpentinized mantle rocks. In the overlying sediments (dolomitic and calcitic marbles of Jurassic to Aptian age), a network of calcitic veins, locally with quartz, formed as a consequence of the infiltration of aqueous saline fluids (salinities up to 34 wt% NaCl are recorded in quartz-hosted fluid inclusions) at moderate temperatures ( 220 °C). These brines likely derived from the dissolution of the local Triassic evaporites. In the upper part of the metasomatic system, upward movement of fluids is limited by the Albian metasediments, which likely acted as an impermeable layer. The model of fluid circulation in the Saraillé Massif sheds light onto other synchronous metasomatic systems in the Pyrenean realm.

Use of fertility drugs and risk of ovarian cancer: results from a U.S.-based case-control study.

PubMed

Kurta, Michelle L; Moysich, Kirsten B; Weissfeld, Joel L; Youk, Ada O; Bunker, Clareann H; Edwards, Robert P; Modugno, Francesmary; Ness, Roberta B; Diergaarde, Brenda

2012-08-01

Previous studies examining associations between use of fertility drugs and ovarian cancer risk have provided conflicting results. We used data from a large case-control study to determine whether fertility drug use significantly impacts ovarian cancer risk when taking into account parity, gravidity, and cause of infertility. Data from the Hormones and Ovarian Cancer Prediction (HOPE) study were used (902 cases, 1,802 controls). Medical and reproductive histories were collected via in-person interviews. Logistic regression was used to calculate ORs and 95% confidence intervals (CI). Models were adjusted for age, race, education, age at menarche, parity, oral contraceptive use, breastfeeding, talc use, tubal ligation, and family history of breast/ovarian cancer. Ever use of fertility drugs was not significantly associated with ovarian cancer within the total HOPE population (OR, 0.93; 95% CI, 0.65-1.35) or among women who reported seeking medical attention for infertility (OR, 0.87; 95% CI, 0.54-1.40). We did observe a statistically significant increased risk of ovarian cancer for ever use of fertility drugs among women who, despite seeking medical attention for problems getting pregnant, remained nulligravid (OR, 3.13; 95% CI, 1.01-9.67). These results provide further evidence that fertility drug use does not significantly contribute to ovarian cancer risk among the majority of women; however, women who despite infertility evaluation and fertility drug use remain nulligravid, may have an elevated risk for ovarian cancer. Our results suggest that fertility drug use does not significantly contribute to overall risk of ovarian cancer when adjusting for known confounding factors. ©2012 AACR.

The effects of substrate size, surface area, and density on coat thickness of multi-particulate dosage forms.

PubMed

Heinicke, Grant; Matthews, Frank; Schwartz, Joseph B

2005-01-01

Drugs layering experiments were performed in a fluid bed fitted with a rotor granulator insert using diltiazem as a model drug. The drug was applied in various quantities to sugar spheres of different mesh sizes to give a series of drug-layered sugar spheres (cores) of different potency, size, and weight per particle. The drug presence lowered the bulk density of the cores in proportion to the quantity of added drug. Polymer coating of each core lot was performed in a fluid bed fitted with a Wurster insert. A series of polymer-coated cores (pellets) was removed from each coating experiment. The mean diameter of each core and each pellet sample was determined by image analysis. The rate of change of diameter on polymer addition was determined for each starting size of core and compared to calculated values. The core diameter was displaced from the line of best fit through the pellet diameter data. Cores of different potency with the same size distribution were made by layering increasing quantities of drug onto sugar spheres of decreasing mesh size. Equal quantities of polymer were applied to the same-sized core lots and coat thickness was measured. Weight/weight calculations predict equal coat thickness under these conditions, but measurable differences were found. Simple corrections to core charge weight in the Wurster insert were successfully used to manufacture pellets having the same coat thickness. The sensitivity of the image analysis technique in measuring particle size distributions (PSDs) was demonstrated by measuring a displacement in PSD after addition of 0.5% w/w talc to a pellet sample.

The "green stones" of Valtellina and Valchiavenna (central Alps, northern Italy)

NASA Astrophysics Data System (ADS)

Cavallo, Alessandro

2015-04-01

Valtellina and Val Chiavenna (Sondrio, Central Alps, northern Italy) are traditionally areas of production of building and ornamental stones (e.g. Serizzo Ghiandone, Serizzo Valmasino, San Fedelino Granite), and among these the "green stones" have a leading position. These stones had an extensive use in Lombardy, as well as abroad (e.g Switzerland). The "green stones" are related to the two mafic-ultramafic bodies of Valmalenco and Chiavenna, where the two largest quarrying districts of the Province of Sondrio are located. Until the early decades of the XX century, serpentinites (and other lithologies from Valtellina) were also extracted from the erratic boulders of Brianza (north of Milan), but at present time the law protects the few remaining boulders. The extracted and processed materials are various: serpentinites, ophicalcites, soapstones. Even the "Stone of Tresivio", used in the past in important monuments of Valtellina, could be classified among the "green stones" in a broad sense: it is a green chloritic schist with scarce and thin ferriferous calcitic veins, pertaining to the sedimentary "Servino" Formation. In recent times, the ancient quarries of this stone were rediscovered near the homonymous village, a few kilometers from Sondrio. There are also historic reports about other "green stones", used in ancient times, such as the "Stone of Grosio", a chloritic schist, and the "Bormio Prasinite". Currently the extraction and processing of "green stones" occurs mostly in Valmalenco, with 22 active serpentinite quarries and a gross volume of 70000 m3 extracted per year, with a yield of about 50%. The Malenco serpentinite (interpreted as sub-continental mantle rocks) forms a 1-2 km thick tabular body, outcropping over an area of about 170 km2, almost entirely confined within the boundaries of the valley. The antigoritic serpentinites (with variable amounts of olivine, clinopyroxene, chlorite and magnetite) are moderately up to strongly foliated, sometimes folded, and are processed in two main commercial varieties: schistose ("serpentinoscisto") and massive ("serpentino da taglio"). In Valmalenco, the extraction and processing of schistose serpentinites for the production of slabs ("piode", splitted by hand with hammer and chisel), used in roofing and flooring, dates back at least to the XIV century. From the traditional underground extraction, the quarrying activities moved to the modern open-cast extraction in the seventies. The renowned quality of the secular serpentinite roof coverings is related to the excellent physical and mechanical properties, especially the flexural strength (average values around 90-100 MPa), very low porosity and the thaw/freezing resistance. The "massive" serpentinite achieved a special place in the national and international market of ornamental stones: the several extracted varieties (Serpentino Classico, Verde Vittoria, Verde Perlato, Verde Mare, Verde Principe, Verde Torre S. Maria), in addition to the excellent technical properties (flexural strength and thermal properties) that promote specific uses, make these stones much appreciated worldwide (e.g. Bundestag in Berlin, Germany). As part of the "green stones" of Valmalenco, two currently abandoned ophicalcite quarries have been active in the recent past. The extraction and processing of soapstone ("pietra ollare" or "pietra laugera", a talc and/or chlorite rich ultramafic/mafic rock) in Valmalenco and Valchiavenna probably dates back to the Iron Age; in Valchiavenna it is documented with certainty since Roman times and the Middle Ages. The extraction and processing of soapstone peaked around the middle of the XVIII century, with a dozen quarries and about 300 workers involved, between Chiavenna and Piuro. A limited production of soapstone is still active in the municipalities of Piuro (talc-olivine-tremolite fels) and Chiesa in Valmalenco (chlorite schist), where in addition to the traditional cooking pots ("Lavecc"), there is a growing art work and gift items production. With the exception of two companies that have reached an industrial production level, the remaining 24 companies operating in Valmalenco are on an artisan level, and are grouped in the "Consorzio Artigiani Cavatori Valmalenco". The consortium, already engaged in the management of a permanent storage of explosives at the service of the quarries, promotes and subsidizes economically various initiatives aimed at the enhancement of stone products and the development of this craft. The consortium is a promoter of a cultural initiative aimed at the restoration of an underground quarry and the ancient paths of "Giovello", a historic site for the extraction and processing of serpentinite.

EGFR mutations predict a favorable outcome for malignant pleural effusion of lung adenocarcinoma with Tarceva therapy.

PubMed

Guo, Haisheng; Wan, Yunyan; Tian, Guangyan; Liu, Qinghua; Kang, Yanmeng; Li, Yuye; Yao, Zhouhong; Lin, Dianjie

2012-03-01

The aim of the present study was to evaluate the therapeutic effects and adverse reactions of Tarceva treatment for malignant pleural effusion (MPE) caused by metastatic lung adenocarcinomas. One hundred and twenty-eight patients who failed first-line chemotherapy drug treatment were divided into a mutation and a non-mutation group according to the presence or absence of epidermal growth factor receptor (EGFR) mutations. Each patient received closed drainage combined with simple negative pressure suction after thoracoscopic talc poudrage pleurodesis and oral Tarceva treatment. Short-term and long-term clinical therapeutic effects of Tarceva were evaluated. The EGFR mutation rate in pleural metastatic tissues of lung adenocarcinoma acquired through video-assisted thoracoscopic surgery was higher compared to that in surgical resection specimens, plasma specimens and pleural effusion specimens compared to previously reported results. There were significant statistical differences in the average extubation time (p<0.01), drainage volume of pleural effusion (p<0.05), Karnofsky score and formation of encapsulated pleural effusion 4 weeks after surgery (p<0.05) between these two groups. The number of patients with mild pleural hypertrophy in the mutation group was significantly higher compared to the non-mutation group (p<0.01), while the number of patients with severe pleural hypertrophy was significantly reduced (p<0.05). There was significant statistical discrepancy between these two groups in terms of improvement of peripheral blood carcinoembryonic antigen and tissue polypeptide antigen after 4 weeks of therapy. The complete remission rate and the efficacy rate were higher in the mutation group compared to that in the non-mutation group (p<0.05). There was a longer overall survival time after Tarceva treatment in patients with EGFR mutations than those without EGFR mutation. EGFR mutations predict a favorable outcome for malignant pleural effusion of lung adenocarcinoma with Tarceva therapy. Detection of EGFR mutations may determine the responsiveness of malignant pleural effusion to Tarceva treatment.

Impact ionisation mass spectrometry of platinum-coated olivine and magnesite-dominated cosmic dust analogues

NASA Astrophysics Data System (ADS)

Hillier, Jon K.; Sternovsky, Z.; Kempf, S.; Trieloff, M.; Guglielmino, M.; Postberg, F.; Price, M. C.

2018-07-01

Impact ionisation mass spectrometry enables the composition of cosmic dust grains to be determined in situ by spacecraft-based instrumentation. The proportion of molecular ions in the impact plasma is a function of the impact velocity, making laboratory calibration vital for the interpretation of the mass spectra, particularly at the low velocities typical of lunar or asteroid encounters. Here we present an analysis of laboratory impact ionisation mass spectra from primarily low (<15 km s-1) velocity impacts of both olivine and magnesite-dominated particles onto the SUrface Dust Mass Analyzer (SUDA) laboratory mass spectrometer. The cation mass spectra show characteristic peaks due to their constituent elements, with Mg, Al, Si, C, Ca, O and Fe frequently present. Contaminant species from the conductive coating process (B, Na, K, C, Pt) also occur, at varying frequencies. Possible saponite or talc inclusions in the magnesite particles are revealed by the presence of Si, Fe, Ca and Al in the magnesite mass spectra. Magnesium is clearly present at the lowest impact velocities (3 km s-1), at which alkali metals were presumed to dominate. Peaks attributed to very minor amounts of water or hydroxyl present in the grains are also seen at low velocities in both cation and anion mass spectra, demonstrating the feasibility of impact ionisation mass spectrometry in identifying hydrated or hydrous minerals, during very low velocity encounters or with very low abundances of water or hydroxy groups, in the impinging grains. Velocity thresholds for the reliable identification of the major elements within the magnesite and olivine cation spectra are presented. Additionally, relative sensitivity factors for Mg (5.1), Fe (1.5) and O (0.6) with respect to Si, in the olivine particles, at impact speeds >19 km s-1, were found to be very similar to those previously determined for orthopyroxene-dominated particles, despite different target and projectile materials. This confirms that quantitative analyses of mineral dust grain composition in space is viable despite initially poorly-constrained mineralogy.

Structural, mineralogical and geochemical constraints on the atypical komatiite-hosted Turret deposit in the Agnew-Mt. White district, Western Australia

NASA Astrophysics Data System (ADS)

Voute, F.; Thébaud, N.

2015-08-01

In the Norseman-Wiluna belt, Yilgarn Craton, the Agnew-Mt. White district is the host of many gold deposits. Located in the hinge of the regional Lawlers anticline, the Turret gold deposit is structurally controlled by the Table Hill shear zone that transects the Agnew Ultramafic unit. Geochemistry, coupled with petrographic data, allowed the delineation of the paragenetic sequence associated with gold mineralisation and include (1) a pervasive talc-carbonate alteration assemblage, (2) a pre-mineralisation stage associated with pervasive arsenopyrite + chalcopyrite + pyrrhotite + pyrite alteration, followed by (3) a late deformation event along a dilatational segment of the main Table Hill shear zone, leading to the formation of a breccia hosting a Cu-Bi-Mo-Au (± Ag ± Zn ± Te ± W) metal assemblage. The presence of Au-Ag-Cu alloys, native bismuth, chalcopyrite and other Bi-Te-S phases in the mineralisation stage suggest that gold may have been scavenged from the hydrothermal fluids by composite Bi-Te-Cu-Au-Ag-S liquids or melts. Using this mineral paragenetic sequence, together with mineralogical re-equilibration textures observed, we show that the gold deposition at Turret occurred over a temperature range approximately between c. 350 and 270 °C. This temperature range, together with the structural control and typical mesothermal alteration pattern including carbonate-chlorite alteration, shows that the Turret deposit shares common characteristics with the orogenic gold deposit class. However, the metal association of Cu, Au, Bi, and Mo, the quartz-poor, and high copper-sulphide content (up to 15 %) are characteristics that depart from the typical orogenic gold deposit mineralogy. Through comparison with similar deposits in the Yilgarn Craton and worldwide, we propose that the Turret deposit represents an example of a porphyry-derived Au-Cu-Bi-Mo deposit.

Methods for quantitative infrared directional-hemispherical and diffuse reflectance measurements using an FTIR and a commercial integrating sphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blake, Thomas A.; Johnson, Timothy J.; Tonkyn, Russell G.

Infrared integrating sphere measurements of solid samples are important in providing reference data for contact, standoff and remote sensing applications. At the Pacific Northwest National Laboratory (PNNL) we have developed protocols to measure both the directional-hemispherical ( and diffuse (d) reflectances of powders, liquids, and disks of powders and solid materials using a commercially available, matte gold-coated integrating sphere and Fourier transform infrared spectrometer. Detailed descriptions of the sphere alignment and its use for making these reflectance measurements are given. Diffuse reflectance values were found to be dependent on the bidirectional reflection distribution function (BRDF) of the sample and themore » solid angle intercepted by the sphere’s specular exclusion port. To determine how well the sphere and protocols produce quantitative reflectance data, measurements were made of three diffuse and two specular standards prepared by the National institute of Standards and Technology (NIST, USA), LabSphere Infragold and Spectralon standards, hand-loaded sulfur and talc powder samples, and water. The five NIST standards behaved as expected: the three diffuse standards had a high degree of “diffuseness,” d/ = D > 0.9, whereas the two specular standards had D ≤ 0.03. The average absolute differences between the NIST and PNNL measurements of the NIST standards for both directional-hemispherical and diffuse reflectances are on the order of 0.01 reflectance units. Other quantitative differences between the PNNL-measured and calibration (where available) or literature reflectance values for these standards and materials are given and the possible origins of discrepancies are discussed. Random uncertainties and estimates of systematic uncertainties are presented. Corrections necessary to provide better agreement between the PNNL reflectance values as measured for the NIST standards and the NIST reflectance values for these same standards are also discussed.« less

Ventilatory function in rubber processing workers: acute changes over the workshift.

PubMed

Governa, M; Comai, M; Valentino, M; Antonicelli, L; Rinaldi, F; Pisani, E

1987-02-01

When considering rubber tyre manufacturing from an occupational health viewpoint, three areas may be identified in which exposure to respirable materials are potentially harmful: the processing, curing, and talc areas. A study of the ventilatory function of the entire work force employed in the processing area in a rubber tyre manufacturing plant was undertaken to determine whether an acute reduction in lung function occurs over the course of their working shift (the plant worked a three shift system) and whether a chronic exposure to the occupational airborne contaminants causes permanent changes in lung function. The ventilatory function was measured at the worksite at the beginning and immediately after the end of the workshift. No evidence of chronic obstructive pulmonary disease was found and in most cases no significant decline in FEV1 was observed. Only one of the 79 individuals showed a moderate obstruction, measured by the ratio FEV1/FVC which gave the value of 0.55, with no variation over the shift. For non-smokers, the FVC, FEV1, and FEF25-75% were lower in those exposed for more than five years than in those exposed for five years or less. A similar pattern was also observed in the FVC and FEV1 of the smokers. None of these differences was statistically significant. Within each exposure group the pulmonary function of the smokers was lower than that of the non-smokers, but the only significant difference was found in the values of FEF25-75%. Only one man showed a decline in the FEV1/FVC ratio over the shift, but during each shift, a decrease in all the lung function tests was observed. The decrease was smallest during the first of the three shifts. These results are thought to support the hypothesis that there are acute adverse effects over an eight hour shift. Further investigations are needed to discover whether these acute changes in lung function result from a chemical stimulation or irritant receptors in the airways.

Mineral resources of parts of the Departments of Antioquia and Caldas, Zone II, Colombia

USGS Publications Warehouse

Hall, R.B.; Feininger, Tomas; Barrero, L.; Dario, Rico H.; ,; Alvarez, A.

1970-01-01

The mineral resources of an area of 40,000 sq km, principally in the Department of Antioquia, but including small parts of the Departments of Caldas, C6rdoba, Risaralda, and Tolima, were investigated during the period 1964-68. The area is designated Zone II by the Colombian Inventario Minero Nacional(lMN). The geology of approximately 45 percent of this area, or 18,000 sq km, has been mapped by IMN. Zone II has been a gold producer for centuries, and still produces 75 percent of Colombia's gold. Silver is recovered as a byproduct. Ferruginous laterites have been investigated as potential sources of iron ore but are not commercially exploitable. Nickeliferous laterite on serpentinite near Ure in the extreme northwest corner of the Zone is potentially exploitable, although less promising than similar laterites at Cerro Matoso, north of the Zone boundary. Known deposits of mercury, chromium, manganese, and copper are small and have limited economic potentia1. Cement raw materials are important among nonmetallic resources, and four companies are engaged in the manufacture of portland cement. The eastern half of Zone II contains large carbonate rock reserves, but poor accessibility is a handicap to greater development at present. Dolomite near Amalfi is quarried for the glass-making and other industries. Clay saprolite is abundant and widely used in making brick and tiles in backyard kilns. Kaolin of good quality near La Union is used by the ceramic industry. Subbituminous coal beds of Tertiary are an important resource in the western part of the zone and have good potential for greater development. Aggregate materials for construction are varied and abundant. Deposits of sodic feldspar, talc, decorative stone, and silica are exploited on a small scale. Chrysotils asbestos deposits north of Campamento are being developed to supply fiber for Colombia's thriving asbestos-cement industry, which is presently dependent upon imported fiber. Wollastonite and andalusite are potential resources not exploitable now.

[Effects of resolving phlegm method on fibrinolytic status in non-alcoholic steatohepatitis patients of phlegm and blood-stasis syndrome].

PubMed

Chen, Li; Jiang, Yang-Kun; Cai, Yan-Bo

2006-12-01

To observe the effect of resolving phlegm method (RPM) on fibrinolytic status in non-alcoholic steatohepatitis (NASH) patients of phlegm blood-stasis (PBS) syndrome type. Sixty-two patients were randomly assigned to 2 groups, namely the treated group (n = 34) treated with Chinese herbs for resolving phlegm and dampness, smoothing liver and gallbladder, promoting blood circulation and removing blood stasis (composition: Indigo Naturalis 10 g, Alumen 3 g, Semen Cassiae 15 g, Fructus Crataegi 15 g, vinegar prepared Radix Bupleuri 10 g, Radix Curcumae 10 g, Radix Salviae Miltiorrhizae 12 g, Herba Lycopi 12 g, talc 12 g and Radix Glycyrrhizae 2 g), one dose twice per day orally, and the control group (n = 28) with ursodeoxycholic acid tablet (UAT) 150 mg three times per day. The treatment course for both groups was 12 weeks. Liver function (ALT, AST, ALP), insulin resistance (IR) index represented by homeostasis model-IR (HOMA-IR) and insulin (Ins), levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1), as well as main symptoms and physical signs were assessed before and after treatment. (1) Compared with those before treatment, levels of ALT, AST, HOMA-IR, t-PA, PAl-1 and main symptoms were all improved in the treated group (P < 0.05 or P < 0.01); (2) There was significant difference in ALP, HOMA-IR, t-PA and PAI-1 between the treated group and the control group (P < 0.05 or P < 0.01); (3) The improvement in liver function related indexes in the control group was mainly the level of ALT, t-PA (P < 0.01), and also shown on HOMA-IR, Ins and PAI-1. RPM could effectively improve liver function and fibrinolytic status. Its effect was better than that of UAT.

Accurate wavelength measurements of a putative standard for near-infrared diffuse reflection spectrometry.

PubMed

Isaksson, Tomas; Yang, Husheng; Kemeny, Gabor J; Jackson, Richard S; Wang, Qian; Alam, M Kathleen; Griffiths, Peter R

2003-02-01

The diffuse reflection (DR) spectrum of a sample consisting of a mixture of rare earth oxides and talc was measured at 2 cm-1 resolution, using five different accessories installed on five different Fourier transform near-infrared (FT-NIR) spectrometers from four manufacturers. Peak positions for 37 peaks were determined using two peak-picking algorithms: center-of-mass and polynomial fitting. The wavenumber of the band center reported by either of these techniques was sensitive to the slope of the baseline, and so the baseline of the spectra was corrected using either a polynomial fit or conversion to the second derivative. Significantly different results were obtained with one combination of spectrometer and accessory than the others. Apparently, the beam path through the interferometer and DR accessory was different for this accessory than for any of the other measurements, causing a severe degradation of the resolution. Spectra measured on this instrument were removed as outliers. For measurements made on FT-NIR spectrometers, it is shown that it is important to check the resolution at which the spectrum has been measured using lines in the vibration-rotation spectrum of atmospheric water vapor and to specify the peak-picking and baseline-correction algorithms that are used to process the measured spectra. The variance between the results given by the four different methods of peak-picking and baseline correction was substantially larger than the variance between the remaining five measurements. Certain bands were found to be more suitable than others for use as wavelength standards. A band at 5943.13 cm-1 (1682.62 nm) was found to be the most stable band between the four methods and the six measurements. A band at 5177.04 cm-1 (1931.61 nm) has the highest precision between different measurements when polynomial baseline correction and polynomial peak-picking algorithms are used.

Comparison of methanogen diversity of yak (Bos grunniens) and cattle (Bos taurus) from the Qinghai-Tibetan plateau, China.

PubMed

Huang, Xiao Dan; Tan, Hui Yin; Long, Ruijun; Liang, Juan Boo; Wright, André-Denis G

2012-10-19

Methane emissions by methanogen from livestock ruminants have significantly contributed to the agricultural greenhouse gas effect. It is worthwhile to compare methanogen from "energy-saving" animal (yak) and normal animal (cattle) in order to investigate the link between methanogen structure and low methane production. Diversity of methanogens from the yak and cattle rumen was investigated by analysis of 16S rRNA gene sequences from rumen digesta samples from four yaks (209 clones) and four cattle (205 clones) from the Qinghai-Tibetan Plateau area (QTP). Overall, a total of 414 clones (i.e. sequences) were examined and assigned to 95 operational taxonomic units (OTUs) using MOTHUR, based upon a 98% species-level identity criterion. Forty-six OTUs were unique to the yak clone library and 34 OTUs were unique to the cattle clone library, while 15 OTUs were found in both libraries. Of the 95 OTUs, 93 putative new species were identified. Sequences belonging to the Thermoplasmatales-affiliated Linage C (TALC) were found to dominate in both libraries, accounting for 80.9% and 62.9% of the sequences from the yak and cattle clone libraries, respectively. Sequences belonging to the Methanobacteriales represented the second largest clade in both libraries. However, Methanobrevibacter wolinii (QTPC 110) was only found in the cattle library. The number of clones from the order Methanomicrobiales was greater in cattle than in the yak clone library. Although the Shannon index value indicated similar diversity between the two libraries, the Libshuff analysis indicated that the methanogen community structure of the yak was significantly different than those from cattle. This study revealed for the first time the molecular diversity of methanogen community in yaks and cattle in Qinghai-Tibetan Plateau area in China. From the analysis, we conclude that yaks have a unique rumen microbial ecosystem that is significantly different from that of cattle, this may also help to explain why yak produce less methane than cattle.

Comparison of methanogen diversity of yak (Bos grunniens) and cattle (Bos taurus) from the Qinghai-Tibetan plateau, China

PubMed Central

2012-01-01

Background Methane emissions by methanogen from livestock ruminants have significantly contributed to the agricultural greenhouse gas effect. It is worthwhile to compare methanogen from “energy-saving” animal (yak) and normal animal (cattle) in order to investigate the link between methanogen structure and low methane production. Results Diversity of methanogens from the yak and cattle rumen was investigated by analysis of 16S rRNA gene sequences from rumen digesta samples from four yaks (209 clones) and four cattle (205 clones) from the Qinghai-Tibetan Plateau area (QTP). Overall, a total of 414 clones (i.e. sequences) were examined and assigned to 95 operational taxonomic units (OTUs) using MOTHUR, based upon a 98% species-level identity criterion. Forty-six OTUs were unique to the yak clone library and 34 OTUs were unique to the cattle clone library, while 15 OTUs were found in both libraries. Of the 95 OTUs, 93 putative new species were identified. Sequences belonging to the Thermoplasmatales-affiliated Linage C (TALC) were found to dominate in both libraries, accounting for 80.9% and 62.9% of the sequences from the yak and cattle clone libraries, respectively. Sequences belonging to the Methanobacteriales represented the second largest clade in both libraries. However, Methanobrevibacter wolinii (QTPC 110) was only found in the cattle library. The number of clones from the order Methanomicrobiales was greater in cattle than in the yak clone library. Although the Shannon index value indicated similar diversity between the two libraries, the Libshuff analysis indicated that the methanogen community structure of the yak was significantly different than those from cattle. Conclusion This study revealed for the first time the molecular diversity of methanogen community in yaks and cattle in Qinghai-Tibetan Plateau area in China. From the analysis, we conclude that yaks have a unique rumen microbial ecosystem that is significantly different from that of cattle, this may also help to explain why yak produce less methane than cattle. PMID:23078429

Concealing a shiny facial skin appearance by an Aerogel-based formula. In vitro and in vivo studies.

PubMed

Cassin, G; Diridollou, S; Flament, F; Adam, A S; Pierre, P; Colomb, L; Morancais, J L; Qiu, H

2018-02-01

To explore, in vitro and in vivo, the potential interest of an Aerogel-based formula, in concealing a naturally shiny facial skin. In vitro, various formulae and ingredients were applied as a thin film onto contrast plates and studied through measuring the shine induced following pump spraying of a mixture of oleic acid and mineral water as a sebum/sweat mix model. In such a test, an Aerogel ingredient led to very positive results. In vivo, two different formulae with various concentrations of Aerogel were randomly tested on half side of the face vs. bare side of Chinese women, under some provocative environmental conditions, known to enhance facial shine. These conditions comprised a normal activity under a hot and highly humid summer time followed - or not - by a hamam session. Both studies included comparative evaluations using a half-face procedure (treated/untreated or vehicle). In the first case, evaluations were quantitatively carried out, whereas the second one was based on a quantitative self-evaluations from standardized full-face photographs RESULTS: In vitro, the tested Aerogel, incorporated at 1% or 2% concentration in a common O/W cosmetic emulsion, shows an immediate light scattering effect, thereby masking shine. Such effect appears of much higher amplitude than that of two other tested particulate ingredients (Talc and Perlite). A noticeable remanence of anti-shine effect was confirmed in vivo in extreme conditions. The latter was self-perceived by all participants in the second study. This result is likely related to the super hydrophobic behaviour of the Aerogel. As cosmetic ingredient, this new Aerogel appears as a highly promising ingredient for concealing the facial skin shine, a source of complaint from many consumers living in hot and humid regions. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

The role of detachment faulting in slow seafloor spreading: First results from cruise JC132 to the MAR at 13N

NASA Astrophysics Data System (ADS)

Reston, T. J.; Falder, M.; Peirce, C.; Simão, N.; Searle, R. C.; MacLeod, C. J.

2016-12-01

Our understanding of the processes of seafloor spreading at slow-spreading mid-ocean ridges is undergoing a paradigm shift as it has become increasingly clear that much of the slowly spread seafloor has not been built solely by the symmetric accretion of the products of partial melting to the trailing edges of the separating plates, but that tectonic stretching on large-offset normal (`detachment') faults, weakened by the penetration of water and production of weak phyllosilicates (e.g. talc), also plays a fundamental role, unroofing plutonic and partially serpentinized mantle footwalls to form `oceanic core complexes' (OCCs). However, fundamental aspects of OCC structure and evolution, and the detachment process itself, are still poorly understood: it is not clear, and consequently hotly debated, whether the controlling faults are seismically active, what their 3D geometry is, how they are linked with the supply and emplacement of magma and, crucially, how far detachments continue laterally in the sub-surface and/or if they link at depth. Our understanding of the 3D geometry and mechanics of detachment faults is limited by a paucity of observations from actively forming OCCs, and in particular the lack of sub-surface images from which the geometry and extent of surface features can be traced to depth, the lack of detailed P- and S-wave 3D-volume velocity models to reveal how detachments relate to magmatic accretion in time and space, and the lack of coincident observations of local seismicity to determine the focus of active deformation. To investigate these key questions, in Jan-Feb 2016 we collected a combined MCS - wide-angle seismic dataset, and high resolution near surface and near seafloor bathymetry and magnetics, to complement passive recordings of microseismicity made in 2014. We discuss the aims of the cruise, and present first results.

Model for the Evolution of an Oceanic Core Complex and its Hydrothermal Vent on the Ultraslow-Spreading Mid Cayman Spreading Center

NASA Astrophysics Data System (ADS)

Harding, J.; Van Avendonk, H. J.; Hayman, N. W.; Grevemeyer, I.; Peirce, C.

2016-12-01

The Mid Cayman Spreading Center (MCSC) is an ultraslow-spreading center (15 mm yr-1 full rate) along the Caribbean-North American plate boundary. Despite the paradigm that ultraslow-spreading centers are amagmatic and cold, two hydrothermal vent fields have recently been discovered along the MCSC. The Beebe Vent Field is a black smoker in the northern axial deep, and the Von Damm Vent Field (VDVF) is a moderate-temperature, talc precipitating vent found atop an oceanic core complex (OCC). This OCC, "Mt. Dent", is a large (3 km high) massif that formed beneath a detachment fault, which exhumed lower crustal and upper mantle material. The CaySeis Experiment was conducted in April, 2015 in order to collect wide-angle refraction data of the MCSC crust and upper mantle. We modeled the across-axis crustal structure of Mt. Dent as well as the surrounding lithosphere using 2.5D P-wave tomography. Using this tomographic model, along with geochemistry, we propose a model for the formation and evolution of the OCC Mt. Dent and the VDVF. A detachment fault formed in a magma-poor environment due to a pulse of magmatism, producing a large gabbro body that was then exhumed and rotated into the OCC footwall. Once magmatism waned and the gabbroic body cooled, the OCC was faulted and fractured due to plate flexure and increased tectonic extensional stress in the naturally cold and thick lithosphere. These faults provide a permeable and deep network of hydrothermal pathways that mine deep lithospheric heat and expose gabbro and fresh mantle peridotite. This model is consistent with the basalt geochemistry, hydrothermal fluid geochemistry, and the distribution of brittle vs. ductile structures along the detachment shear zone. The VDVF is therefore a product of a pulse of magmatism in an overall melt-poor environment, conditions that may be found at other ultraslow-spreading ridges.

Laboratory Far-infrared Spectroscopy Of Terrestrial Phyllosilicates To Support Analysis Of Cosmic Dust Spectra.

NASA Astrophysics Data System (ADS)

Yesiltas, Mehmet; Brusentsova, T.; Peale, R.; Maukonen, D.; Figueiredo, P.; Harlow, G. H.; Ebel, D. S.; Nissinboim, A.; Sherman, K.; Lisse, C. M.

2012-01-01

Poster Abstract: 219th AAS Meeting M. Yesiltas1, T. Brusentsova1, R. E. Peale1, D. Maukonen1, P. Figueiredo1, G. E. Harlow2, D. S. Ebel2, A. Nissinboim2, K. Sherman2, and C. M. Lisse3 Remote spectral detection of hydrated minerals is of general interest in the solar system and dusty circumstellar disks. This paper presents spectroscopy of terrestrial phyllosilicate minerals in the wavelength range 15 - 250 µm to support interpretation of returned data from far-IR space-missions such as the Herschel Space Observatory. The far-IR spectral region beyond 15 micron wavelength is especially diagnostic of mineral composition and crystal structure. Relatively little far-IR spectral data exists in the literature on suitably-characterized naturally-occurring phyllosilicate minerals in the wavelength range 60-210 microns corresponding to the PACS instrument of Herschel Space Observatory. Extending the database of laboratory far-IR spectra of terrestrial mineral analogs is therefore desirable and timely. Seventeen phyllosilicate minerals expected in various astronomical environments were sampled from the American Museum of Natural History for diversity and astrophysical relevancy, based on their identification in Stardust, in stratospheric IDP samples, or in meteorites. These include serpentines (Antigorite and Chrysotile), smectites (Talc, Pyrophyllite, Vermiculite, Montmorillonite, Beidellite, Saponite, Nontronite and Hectorite), chlorites (Clinochlore), micas (Muscovite, Paragonite, Margarite, Clintonite, Biotite and Illite), and kaolinites (Dickite, Nacrite, Kaolinite, Halloysite, Attapulgite and Sepiolite). Spectra of micron-sized powder suspensions in polyethelyne pellets reveal prominent and characteristic far-IR features, which differ significantly in some cases from already published spectra, where available. Acknowledgements : This research was supported by NASA-JPL Contract # 1327221. 1Department of Physics, University of Central Florida, Orlando FL 32816 USA2American Museum of Natural History, New York NY 10024 USA3Johns Hopkins University Applied Physics Laboratory, Laurel MD 20723 USA

Mineralogy and origin of stichtite in chromite-bearing serpentinites

NASA Astrophysics Data System (ADS)

Ashwal, Lewis D.; Cairncross, Bruce

Stichtite, a rare (14 known localities worldwide) hydrated carbonate-hydroxide of Mg and Cr with ideal formula Mg6Cr2 (OH)16 CO3 . 4H2O, occurs exclusively in Cr-rich serpentinites of ophiolites or greenstone belts. Physical properties (hardness=1.5-2, specific gravity=2.16-2.2, perfect basal [0001] cleavage, grain size commonly < 100 μm) resemble talc, but the mineral has an attractive purple to lilac color; chemical analyses demonstrate it to be a non-silicate. Stichtite generally occurs as irregular to rounded masses (< 1 cm - 30 cm across) and as veinlets (< 1 mm - > 2 cm wide) within serpentinite. Macroscopic and microscopic textures, such as crosscutting veinlets and stringers, demonstrate that stichtite formation invariably post-dated serpentinization. In some specimens stichtite surrounds relict grains of Cr-rich spinel; in others stichtite has completely replaced euhedral or subhedral chromites. Chemical analyses of stichtites reveal substantial substitution of Al and Fe3+ for Cr in specimens from many localities, reflecting a possible compositional continuum between stichtite and rhombohedral polymorphs hydrotalcite (Mg6Al2 (OH)16 CO3 . 4H2O) and pyroaurite (Mg6Fe2 (OH)16 CO3 . 4H2O). We report the first electron microprobe analyses of stichtites from seven localities, and summarize all available published chemical data. Stichtites very likely inherited part of their trivalent cation chemistry from precursor Cr-rich spinels, but stichtite growth apparently post-dated characteristic ``ferritchromit'' alteration, as demonstrated by the depletion of Al and enrichment in Fe3+ in stichtite relative to primary chromite core compositions. Stichtite appears to form by reaction between serpentine and altered chromite, during addition of substantial fluid, either as separate H2O and CO2 phases, or as a mixed volatile phase. Such reactions must involve removal of substantial SiO2, possibly by transport and remote deposition of silica by throughgoing aqueous and carbonic fluid.

Some Speculations Concerning The Abitibi Greenstone Belt As A Possible Analog To The Early Martian Crust

NASA Astrophysics Data System (ADS)

Russell, M.; Allwood, A.; Anderson, R. B.; Atkinson, B.; Beaty, D.; Bristow, T. F.; Ehlmann, B. L.; Grotzinger, J. P.; Hand, K. P.; Halevy, I.; Hurowitz, J. A.; Knoll, A.; McCleese, D. J.; Milliken, R.; Stolper, D. A.; Stolper, E. M.; Tosca, N. J.; Agouron Mars Simulation Field Team

2011-12-01

The Noachian crust of Mars comprises basaltic and, potentially, komatiitic lavas derived from a hot mantle slightly more reducing and sulfur-rich than that of the Earth. Ultramafic volcanic sequences of the ~2.7Ga Tisdale Group of the Abitibi Greenstone Belt, Ontario, provide a potential analog to these early martian lavas. The Abitibi rocks are a possible source of quartz veins carrying, in places, pyrite, carbonate and gold. These were hydrothermally introduced into volcanic and sedimentary rocks during greenschist metamorphism. Kilometer-scale talc-magnesite zones, resulting from the carbonation of serpentinized ultramafics, may have been the source and seawater, with some magmatic addition, was probably responsible for the pervasive alteration, although the chemical nature of hydrothermal fluids circulating in such piles depends upon the temperature of wall-rock interactions and is largely independent of fluid origin. Any sulfides and gold in unaltered ultramafic putative source rocks may have been lost to the invasive convective fluids. Given high heat flow and the presence of a hydrosphere, hydrothermal convection cells were probably the main mechanism of heat transfer through the crust on both planets. Exploration of the Abitibi belt provides a template for possible martian exploration strategies. Orbital remote sensing indicates that some ultramafic rocks on Mars have also been serpentinized and isolated areas of magnesite have been recently discovered, overlying altered mafic crust, with characteristic ridges at scales of a few hundred meters. While cogent arguments have been made favoring sedimentary exhalative accumulations of hydrothermal silica of the kind that are known to harbor bacteria on our own planet, no in situ siliceous sinters or even quartz veins have been identified with certainty on Mars. Here, we report on the mineralogic and visible to infrared spectral characteristics of mafic and ultramafic lithologies at Abitibi for comparison to locations on Mars where hydrothermal activity has been proposed.

Distal Impact Ejecta Material in Marine Sediments in the North-Central Pacific Ocean

NASA Astrophysics Data System (ADS)

Leung, I. S.; Hagstrum, J. T.

2006-12-01

We studied a sample of red clay weighing 1.4 grams, derived from a deep sea core (GPC3) located at Latitude 30 degrees N, Longitude 158 degrees W, provided by Jim Broda at the core lab of Woods Hole Oceanographic Institution (supported by NSF). The 65 Ma K/T boundary layer was identified by magnetic susceptibility measurements and Ir anomaly which peaked at a down-hole depth of 2055-2056 cm. We dissolved calcium carbonate in the red clay with dilute HCl to facilitate wet sieving for the size fraction greater than 38 microns. This process yielded 0.0l gram of clean grains from which we hand-picked materials under a binocular microscope. We picked out 40 microtektites (glass spherules, now devitrified), 12 olive- green aggregates composed of talc (probably from alteration of olivine), pyroxene, and magnetite, 6 crystals of biotite, a few magnetic oxide minerals and spherules, and 3 green and 1 blue crystals of silicon carbide (SiC). We are studying the SiC by X-rays. Also, there are abundant quartz grains. Six of the grains we picked out show two sets of shock lamellae decorated by a black substance. Some quartz crystals show mosaic structures. One other grain has a foreign particle embedded in it, while another has two penetrating hollow tubes. These two grains might have been impacted upon by high-velocity "bullets". Because the olive-green aggregates we found have both their mineralogy and texture similar to those often observed in chondrules, in addition to the presence of SiC, which is typically associated with carbonaceous chondrites, we recognize that there seems to be a strong implication that the impactor at Chicxulub which caused extinction of dinosaurs might have been a carbonaceous chondrite which sent the distal ejecta to our core site.

Modeling the hydrothermal circulation and the hydrogen production at the Rainbow site with Cast3M

NASA Astrophysics Data System (ADS)

Perez, F.; Mügler, C.; Charlou, J.; Jean-baptiste, P.

2012-12-01

On the Mid-Atlantic Ridge, the Rainbow venting site is described as an ultramafic-hosted active hydrothermal site and releases high fluxes of methane and hydrogen [1, 2]. This behavior has first been interpreted as the result of serpentinization processes. But geochemical reactions involving olivine and plagioclase assemblages, and leading to chlorite, tremolite, talc and magnetite assemblages, could contribute to the observed characteristics of the exiting fluid [2]. The predominance of one of these geochemical reactions or their coexistence strongly depend on the hydrothermal fluid circulation. We developed and validated a 2D/3D numerical model using a Finite Volume method to simulate heat driven fluid flows in the framework of the Cast3M code [3, 4]. We also developed a numerical model for hydrogen production and transport that is based on experimental studies of the serpentinization processes [5-6]. This geochemical model takes into account the exothermic and water-consuming behavior of the serpentinization reaction and it can be coupled to our thermo-hydrogeological model. Our simulations provide temperatures, mass fluxes and venting surface areas very close to those estimated in-situ [7]. We showed that a single-path model [8] was necessary to simulate high values such as the in-situ measured temperatures and estimated water mass fluxes of the Rainbow site [7]. This single-path model will be used to model the production and transport of hydrogen at the Rainbow hydrothermal site. References [1]Charlou et al. (2010) AGU Monograph series. [2]Seyfried et al. (2011) Geochim. Cosmochim. Acta 75, 1574-1593. [3]http://www-cast3m.cea.fr. [4]Martin & Fyfe (1970) Chem. Geol. 6, 185-202. [5] Marcaillou et al. (2011) Earth and Planet. Sci. Lett. 303, 281-290. [6]Malvoisin et al. (2012) JGR, 117, B01104. [7]Perez et al. (2012) submited to Computational Geosciences. [8]Lowell & Germanovich (2004) AGU, Washington DC, USA.

Steadiness in Dilute Pyroclastic Density Currents

NASA Astrophysics Data System (ADS)

Andrews, B. J.

2015-12-01

Pyroclastic density currents (PDCs) are often unsteady, as evidenced by direct observations of dilute lobes or jets emerging from the fronts of larger currents and by deposits that indicate transient transport and depositional regimes. We used scaled experiments to investigate unsteadiness in dilute PDCs. The experimental currents were run in an 8.5x6.1x2.6 m tank and comprised heated or ambient temperature 20-μm talc powder turbulently suspended in air. Experiments were scaled such that densimetric and thermal Richardson numbers, Froude number, and particle Stokes and settling numbers were dynamically similar to natural dilute PDCs. Although the experiment Reynolds numbers are substantially lower than those of natural PDCs, the experiments are fully turbulent. Experiments were observed with video and high-speed cameras and high-frequency thermocouples. Currents were generated with total eruption durations of 100 s. Unsteadiness in source conditions was produced by interrupting supply for intervals, t, with durations of 1, 2.5, 5, and 10 s in the experimental runs at 35 and 70 s. When t<2.5 s, the currents are indistinguishable from currents with steady supply. In runs with t=2.5-5 s, the individual pulses comprising each current are readily apparent near the source, but decay with distance downstream until the currents appear as single (e.g. steady) flows. In experiments with t=10 s, the 3 pulses comprising each run never merge and the currents remain unsteady. Comparison with the integral turbulent timescale, τ, and current velocity, U, show that unsteadiness is persistent when t>3<τ but currents are steady when t<τ. In currents with 3τ>t>τ, unsteadiness decays such that at a distance of ~4Ut, the currents are again steady. Applied to natural dilute PDCs, our results suggest that currents and their resulting deposits, will only show evidence of unsteadiness if they are disrupted for many seconds and those breaks may "heal" over distances of 100s of meters.

A REAL-TIME COAL CONTENT/ORE GRADE (C2OC) SENSOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rand Swanson

2005-04-01

This is the final report of a three year DOE funded project titled ''A real-time coal content/ore grade (C{sub 2}OG) sensor''. The sensor, which is based on hyperspectral imaging technology, was designed to give a machine vision assay of ore or coal. Sensors were designed and built at Resonon, Inc., and then deployed at the Stillwater Mining Company core room in southcentral Montana for analyzing platinum/palladium ore and at the Montana Tech Spectroscopy Lab for analyzing coal and other materials. The Stillwater sensor imaged 91' of core and analyzed this data for surface sulfides which are considered to be pathfindermore » minerals for platinum/palladium at this mine. Our results indicate that the sensor could deliver a relative ore grade provided tool markings and iron oxidation were kept to a minimum. Coal, talc, and titanium sponge samples were also imaged and analyzed for content and grade with promising results. This research has led directly to a DOE SBIR Phase II award for Resonon to develop a down-hole imaging spectrometer based on the same imaging technology used in the Stillwater core room C{sub 2}OG sensor. The Stillwater Mining Company has estimated that this type of imaging system could lead to a 10% reduction in waste rock from their mine and provide a $650,000 benefit per year. The proposed system may also lead to an additional 10% of ore tonnage, which would provide a total economic benefit of more than $3.1 million per year. If this benefit could be realized on other metal ores for which the proposed technology is suitable, the possible economic benefits to U.S. mines is over $70 million per year. In addition to these currently lost economic benefits, there are also major energy losses from mining waste rock and environmental impacts from mining, processing, and disposing of waste rock.« less

Listvenite formation from peridotite: Insights from Oman Drilling Project hole BT1B and preliminary reaction path model approach.

NASA Astrophysics Data System (ADS)

de Obeso, J. C.; Kelemen, P. B.; Manning, C. E.; Michibayashi, K.; Harris, M.

2017-12-01

Oman Drilling Project hole BT1B drilled 300 meters through the basal thrust of the Samail ophiolite. The first 200 meters of this hole are dominated by listvenites (completely carbonated peridotites) and serpentinites. Below 200 meters the hole is mainly composed of metasediments and metavolcanics. This core provides a unique record of interaction between (a) mantle peridotite in the leading edge of the mantle wedge and (b) hydrous, CO2 rich fluids derived from subducting lithologies similar to those in the metamorphic sole. We used EQ3/6 to simulate a reaction path in which hydrous fluid in equilibrium with qtz + calcite + feldspar + chlorite or smectite reacts with initially fresh peridotite at 100°C (the estimated temperature of alteration, Falk & Kelemen GCA 2015) and 5 kb. Water was first equilibrated with minerals observed during core description in the metamorphic sole at 100°C and 5kb. This fluid is then reacted with olivine enstatite and diopside (Mg#90) approximating the average composition of residual mantle peridotite (harzburgite) in Oman. Secondary minerals resulting from complete reaction are then reacted again with the initial fluid in an iterative process, up to water/rock > 1000. Water/rock close to 1 results in complete serpentinization of the peridotite, with chrysotile, brucite and magnetite as the only minerals. Water/rock >10 produces carbonates, chlorite and talc. Further increasing water/rock to > 100 produces assemblages dominated by carbonates and quartz with minor muscovite, similar to listvenites of hole BT1B that contain qtz + carbonates + Fe-oxyhydroxides + relict spinel ± chromian muscovite and fuchsite. The results of this preliminary model are consistent with the complex veining history of core from BT1B, with carbonate/iron oxide veins in both listvenites and serpentinites interpreted to be the earliest record of peridotite carbonation after initial serpentinization.

Chemistry of chromites from Arroio Grande Ophiolite (Dom Feliciano Belt, Brazil) and their possible connection with the Nama Group (Namibia)

NASA Astrophysics Data System (ADS)

Ramos, Rodrigo Chaves; Koester, Edinei; Porcher, Carla Cristine

2017-12-01

The present paper shows a mineral chemistry study in chromites found in serpentine-talc schists of the Arroio Grande Ophiolite, located in the southeastern Dom Feliciano Belt, near the Brazil/Uruguay border. Using electron microscope scanning and electron microprobe techniques, this study found a supra-subduction zone signature in the chromites, together with evidence of metasomatism. It corroborates previous hypothesis that suggested a supra-subduction zone origin for the protoliths of the Arroio Grande meta-igneous rocks and a metasomatic origin for the chromite-bearing magnesian schists. The studied chromites present high Cr# (0.65-0.77) and Fe2+# (0.88-0.95), low MgO (0.85-2.47 wt%) and TiO2 (0.01-0.19 wt%) and anomalous high concentration of ZnO (up to 1.97 wt%). The results were compared with chemical data from detrital chromites from the Schwarzrand and Fish River Subgroups of the Nama Group (Namibia), demonstrating that they are compositionally similar with those found in the latter. These chromites, in turn, are believed to have been derived from the oceanic Marmora Terrane (Gariep Belt) in the west (present-day coordinates). Taking into consideration that oceanic metamafites from both the latter and the Arroio Grande Ophiolite share common bulk-rock geochemical features (in this paper interpreted as fragments of the same paleo-ocean floor - the Marmora back-arc basin), it is possible to raise the hypothesis that detrital material derived from the studied ophiolite might also be found in Nama Group. It is reinforced by the fact that sediments (related to the Pelotas-Aiguá Batholith granitoids) derived from the easternmost Dom Feliciano Belt, i.e. the region where Arroio Grande Ophiolite is located, is found in both Schwarzrand and Fish River Subgroups. Thus, we suggest that Arroio Grande Ophiolite detrital sediments might also have contributed to the Nama Basin infilling during Late Ediacaran-Lower Cambrian.

Designing an extended release waxy matrix tablet containing nicardipine–hydroxy propyl β cyclodextrin complex

PubMed Central

Al-Zein, Hind; Sakeer, Khalil; Alanazi, Fars K.

2011-01-01

Aim The current study aimed to prepare a sustained release tablet for a drug which has poor solubility in alkaline medium using complexation with cyclodextrin. Nicardipine hydrochloride (NC) a weak basic drug was chosen as a model drug for this study. Method Firstly the most suitable binary system NC-HPβCD was selected in order to improve drug solubility in the intestinal media and then embedding the complexed drug into a plastic matrix, by fusion method, consists of glycerol monostearate (GMS) as an inert waxy substance and polyethylene glycol 4000 (PEG4000) as a channeling agent, after that the final solid dispersion [(NC:HPβCD):GMS:PEG4000] which was prepared at different ratios was mixed with other excipients, avicel PH101, lactose, and talc, to get a tablet owning dissolution profile complying with the FDA and USP requirements for the extended release solid dosage forms. Results Infrared spectroscopy (IR), differential scanning colorimetry (DSC), polarized microscopy and X-ray diffractometry proved that the coevaporation technique was effective in preparing amorphous cyclodextrin complexes with NC and trapping of NC within the HPβCD cavity by dissolving both in ethanol and evaporate the solvent using a rotavapor at 65 °C. Dissolution profile of NC enhanced significantly in pH 6.8 from NC:HPβCD inclusion complex prepared by the rotavapor (t-test Student p < 0.05). The release of NC from tablet containing [(NC:HPβCD):GMS:PEG4000] [(1):0.75:0.5] (w/w/w) solid dispersion (F8) was complying with the FDA dissolution requirements for extended release dosage forms, and studying the kinetics of the release showed that the diffusional contribution is the major factor controlling the drug release from that formula. Conclusion The prepared waxy matrix tablet containing NC complexes with CD shows promising results as extended release tablets. PMID:23960765

Metasomatism, Fluid Overpressure and Brecciation at the Slab-Mantle Interface: Insights from the Livingstone Fault, New Zealand

NASA Astrophysics Data System (ADS)

Tarling, M.; Smith, S. A. F.; Scott, J.

2017-12-01

Juxtaposition of mantle peridotite and serpentinite against quartzofeldspathic and mafic schists occurs along the shallow slab-mantle interface in some subduction zones. This part of the subduction interface has been invoked as a possible source region of episodic tremor and slow slip, yet geological observations of fault zone structures and chemical reactions pertinent to this region are quite rare. The >1000 km long Livingstone Fault in New Zealand is a superbly exposed fault zone that provides a suitable analogue (both in terms of scale and the rock types involved) for the shallow slab-mantle interface. The fault is characterized by a foliated and highly sheared serpentinite mélange tens to several hundreds of meters wide that separates (partially serpentinised) peridotites from quartzofeldspathic schists. Talc- and tremolite-forming metasomatic reactions occurred along the margins of the mélange and around entrained pods due to mixing of serpentinite with silica- and calcium-rich fluids derived from the adjacent quartzofeldspathic schist. The metasomatic reactions generated significant volumes of water at the melange-schist contact that became trapped between the two relatively impermeable fault zone lithologies. On the schist side of the contact, brittle faulting was promoted by the formation of a laterally-continuous silicified zone up to tens of metres wide. On the melange side, a zone up to tens of metres wide of `crackle-breccias' containing veined stockworks of tremolite indicates periodic increases of pore pressure sufficient to cause hydraulic fracture of serpentinite. The crackle-breccias are multi-generational indicating that this process was episodic. Sr and Nd isotope data and permeability calculations suggest that the episodic brecciation process was critical to the transfer of fluids across the melange. Our observations suggest that fluid-producing metasomatic reactions along the shallow slab-mantle interface may contribute to the tremor signal by triggering brecciation events and promoting brittle failure in serpentinite and schist.

Si-Metasomatism During Serpentinization of Jurassic Ultramafic Sea-floor: a Comparative Study

NASA Astrophysics Data System (ADS)

Vogel, M.; Frueh-Green, G. L.; Boschi, C.; Schwarzenbach, E. M.

2014-12-01

The Bracco-Levanto ophiolitic complex (northwestern Italy) represents one of the largest and better-exposed ophiolitic successions in the Northern Apennines. It is considered to be a fragment of heterogeneous Jurassic lithosphere that records tectono-magmatic and alteration histories similar to those documented along the Mid-Atlantic Ridge (MAR), such as at the 15°20'N area and the Atlantis Massif at 30°N. Structural and petrological studies on these rocks provide constraints on metamorphic/deformation processes during formation and hydrothermal alteration of the Jurassic oceanic lithosphere. We present a petrological and geochemical study of serpentinization processes and fluid-rock interaction in the Bracco-Levanto ophiolitic complex and compare these to published data from modern oceanic hydrothermal systems, such as the Lost City hydrothermal field hosted in serpentinites on the Atlantis Massif. Major element and mineral compositional data allow us to distinguish a multiphase history of alteration characterized by: (1) widespread Si-metasomatism during progressive serpentinization, and (2) multiple phases of veining and carbonate precipitation associated with circulation of seawater in the shallow ultramafic-dominated portions of the Jurassic seafloor, resulting in the formation of ophicalcites. In detail, regional variations in Si, Mg and Al content are observed in zones of ophicalcite formation, indicating metasomatic reactions and Si-Al transport during long-lived fluid-rock interaction and channelling of hydrothermal fluids. Rare earth element and isotopic analysis indicate that the Si-rich fluids are derived from alteration of pyroxenes to talc and tremolite in ultramafic rocks at depth. Comparison with serpentinites from the Atlantis Massif and 15°20'N indicates a similar degree of Si-enrichment in the modern seafloor and suggests that Si-metasomatism may be a fundamental process associated with serpentinization at slow-spreading ridge environments. However, in contrast to metasomatic processes at the MAR, we find no geochemical evidence for a gabbroic source of the fluids, and thus, processes leading to Si-rich fluids can be variable in these environments.

By-products of the serpentinization process on the Oman ophiolite : chemical and isotopic composition of carbonate deposits in alkaline springs, and associated secondary phases

NASA Astrophysics Data System (ADS)

Sissmann, O.; Martinez, I.; Deville, E.; Beaumont, V.; Pillot, D.; Prinzhofer, A.; Vacquand, C.; Chaduteau, C.; Agrinier, P.; Guyot, F. J.

2014-12-01

The isotopic compositions (d13C, d18O) of natural carbonates produced by the alteration of basic and ultrabasic rocks on the Oman ophiolite have been measured in order to better understand their formation mechanisms. Fossil carbonates developed on altered peridotitic samples, mostly found in fractures, and contemporary carbonates were studied. The samples bear a large range of d13C. Those collected in veins are magnesian (magnesite, dolomite) and have a carbon signature reflecting mixing of processes and important fractionation (-11‰ to 8‰). Their association with talc and lizardite suggests they are by-products of a serpentinization process, that must have occurred as a carbon-rich fluid was circulating at depth. On the other hand, the carbonates are mostly calcic when formed in alkaline springs, most of which are located in the vicinity of lithological discontinuities such as the peridotite-gabbro contact (Moho). Aragonite forms a few meters below the surface of the ponds in Mg-poor water, and is systematically associated with brucite (Mg(OH)2). This suggests most of the Mg dissolved at depth has reprecipitated during the fluid's ascension through fractures or faults as carbonates and serpentine. Further up, on the surface waters of the ponds (depleted in Mg and D.I.C.), thin calcite films precipitate and reach extremely negative d13C values (-28‰), which could reflect either a biological carbon source, or kinetic fractionation from pumping atmospheric CO2. Their formation represent an efficient and natural process for carbon dioxide mineral sequestration. The d18O signature from all samples confirm the minerals crystallized from a low-temperature fluid. The hyperalkaline conditions (pH between 11 and 12) allowing for these fast precipitation kinetics are generated by the serpentinization process occurring at depth, as indicated by the measured associated H2-rich gas flows (over 50%) seeping out to the surface.

Water, air, Earth and cosmic radiation.

PubMed

Bassez, Marie-Paule

2015-06-01

In the context of the origin of life, rocks are considered mainly for catalysis and adsorption-desorption processes. Here it is shown how some rocks evolve in energy and might induce synthesis of molecules of biological interest. Radioactive rocks are a source of thermal energy and water radiolysis producing molecular hydrogen, H2. Mafic and ultramafic rocks evolve in water and dissolved carbon dioxide releasing thermal energy and H2. Peridotites and basalts contain ferromagnesian minerals which transform through exothermic reactions with the generation of heat. These reactions might be triggered by any heating process such as radioactive decay, hydrothermal and subduction zones or post-shock of meteorite impacts. H2 might then be generated from endothermic hydrolyses of the ferromagnesian minerals olivine and pyroxene. In both cases of mafic and radioactive rocks, production of CO might occur through high temperature hydrogenation of CO2. CO, instead of CO2, was proven to be necessary in experiments synthesizing biological-type macromolecules with a gaseous mixture of CO, N2 and H2O. In the geological context, N2 is present in the environment, and the activation source might arise from cosmic radiation and/or radionuclides. Ferromagnesian and radioactive rocks might consequently be a starting point of an hydrothermal chemical evolution towards the abiotic formation of biological molecules. The two usually separate worlds of rocks and life are shown to be connected through molecular and thermodynamic chemical evolution. This concept has been proposed earlier by the author (Bassez J Phys: Condens Matter 15:L353-L361, 2003, 2008a, 2008b; Bassez Orig Life Evol Biosph 39(3-4):223-225, 2009; Bassez et al. 2011; Bassez et al. Orig Life Evol Biosph 42(4):307-316, 2012, Bassez 2013) without thermodynamic details. This concept leads to signatures of prebiotic chemistry such as radionuclides and also iron and magnesium carbonates associated with serpentine and/or talc, which were discussed at the 2014 European Astrobiology Network Association conference on Signatures of Life.

Hydrogen and oxygen isotope constraints on hydrothermal alteration of the Trinity peridotite, Klamath Mountains, California

USGS Publications Warehouse

Liakhovitch, V.; Quick, J.E.; Gregory, R.T.

2005-01-01

The Trinity peridotite represents a rare opportunity to examine a relatively fertile plagioclase peridotite that was exhumed and later subjected to intrusive events in a seafloor environment, followed by its emplacement and incorporation into a continent. Over 250 stable isotopic determinations on whole rocks and minerals elucidate the hydrothermal evolution of the Trinity complex. All three serpentine polymorphs are present in the Trinity peridotite; these separate on the basis of their ??D values: antigorite, -46 < ??D < -82??? and lizardite and chrysotile, -90 < ??D < -106 and -110 < ??D < -136???, respectively. Antigorite coexists with chlorite, talc, and tremolite in contact aureole assemblages associated with Silurian/Devonian gabbroic plutons. Lizardite and chrysotile alteration carries a meteoric signature, which suggests association with post-emplacement serpentinization, or overprinting of earlier low-temperature seafloor serpentinization. Regionally, contours of ??D values exhibit bull's-eye patterns associated with the gabbroic plutons, with ??D maxima coinciding with the blackwall alteration at the margins on the plutons. In contrast to the hydrogen isotope behavior, oxygen isotope values of the three polymorphs are indistinguishable, spanning the range 5.3 < ??18O< 7.5, and suggesting low integrated fluid fluxes and strongly 18O-shifted fluids. Inferred primary ?? 18O values for peridotite, gabbro, and late Mesozoic granodiorite indicate a progressive 18O enrichment with time for the source regions of the rocks. These isotopic signatures are consistent with the geology, petrochemistry, and geochronology of the Trinity massif, which indicate the following history: (1) lithospheric emplacement and cooling of the peridotite in an oceanic environment ??? 472 Ma; (2) intrusion of gabbroic plutons into cold peridotite in an arc environment between 435 and 404 Ma; and finally (3) intrusion of felsic plutons between 171 and 127 Ma, long after the peridotite was incorporated into the continental crust. Copyright ?? 2005 by V. H. Winston & Son, Inc. All rights reserved.

Pleural Touch Preparations and Direct Visualization of the Pleura during Medical Thoracoscopy for the Diagnosis of Malignancy.

PubMed

Grosu, Horiana B; Vial-Rodriguez, Macarena; Vakil, Erik; Casal, Roberto F; Eapen, George A; Morice, Rodolfo; Stewart, John; Sarkiss, Mona G; Ost, David E

2017-08-01

During diagnostic thoracoscopy, talc pleurodesis after biopsy is appropriate if the probability of malignancy is sufficiently high. Findings on direct visual assessment of the pleura during thoracoscopy, rapid onsite evaluation (ROSE) of touch preparations (touch preps) of thoracoscopic biopsy specimens, and preoperative imaging may help predict the likelihood of malignancy; however, data on the performance of these methods are limited. To assess the performance of ROSE of touch preps, direct visual assessment of the pleura during thoracoscopy, and preoperative imaging in diagnosing malignancy. Patients who underwent ROSE of touch preps during thoracoscopy for suspected malignancy were retrospectively reviewed. Malignancy was diagnosed on the basis of final pathologic examination of pleural biopsy specimens. ROSE results were categorized as malignant, benign, or atypical cells. Visual assessment results were categorized as tumor studding present or absent. Positron emission tomography (PET) and computed tomography (CT) findings were categorized as abnormal or normal pleura. Likelihood ratios were calculated for each category of test result. The study included 44 patients, 26 (59%) with a final pathologic diagnosis of malignancy. Likelihood ratios were as follows: for ROSE of touch preps: malignant, 1.97 (95% confidence interval [CI], 0.90-4.34); atypical cells, 0.69 (95% CI, 0.21-2.27); benign, 0.11 (95% CI, 0.01-0.93); for direct visual assessment: tumor studding present, 3.63 (95% CI, 1.32-9.99); tumor studding absent, 0.24 (95% CI, 0.09-0.64); for PET: abnormal pleura, 9.39 (95% CI, 1.42-62); normal pleura, 0.24 (95% CI, 0.11-0.52); and for CT: abnormal pleura, 13.15 (95% CI, 1.93-89.63); normal pleura, 0.28 (95% CI, 0.15-0.54). A finding of no malignant cells on ROSE of touch preps during thoracoscopy lowers the likelihood of malignancy significantly, whereas finding of tumor studding on direct visual assessment during thoracoscopy only moderately increases the likelihood of malignancy. A positive finding on PET and/or CT increases the likelihood of malignancy significantly in a moderate-risk patient group and can be used as an adjunct to predict malignancy before pleurodesis.

Slip-localization within confined gouge powder sheared at moderate to high slip-velocity

NASA Astrophysics Data System (ADS)

Reches, Zeev; Chen, Xiaofeng; Morgan, Chance; Madden, Andrew

2015-04-01

Slip along faults in the upper crust is always associated with comminution and formation of non-cohesive gouge powder that can be lithified to cataclasite. Typically, the fine-grained powders (grain-size < 1 micron) build a 1-10 cm thick inner-core of a fault-zone. The ubiquitous occurrence of gouge powder implies that gouge properties may control the dynamic weakening of faults. Testing these properties is the present objective. We built a Confined ROtary Cell, CROC, with a ring-shape, ~3 mm thick gouge chamber, with 62.5 and 81.2 mm of inner and outer diameters. The sheared powder is sealed by two sets of seals pressurized by nitrogen. In CROC, we can control the pore-pressure and to inject fluids, and to monitor CO2 and H2O concentration; in addition, we monitor the standard mechanical parameters (slip velocity, stresses, dilation, and temperature). We tested six types of granular materials (starting grain-size in microns): Talc (<250), Kasota dolomite (125-250), ooides grains (125-250), San Andreas fault zone powder (< 840), montmorillonite powder (1-2), kaolinite powder and gypsum. The experimental slip-velocity ranged 0.001-1 m/s, slip distances from a few tens of cm to tens of m, effective normal stress up to 6.1 MPa. The central ultra-microscopic (SEM) observation is that almost invariably the slip was localized along principal-slip-zone (PSZ) within the granular layer. Even though the starting material was loose, coarse granular material, the developed PSZ was cohesive, hard, smooth and shining. The PSZ is about 1 micron thick, and built of agglomerated, ultra-fine grains (20-50 nm) that were pulverized from the original granular material. We noted that PSZs of the different tested compositions display similar characteristics in terms of structure, grain size, and roughness. Further, we found striking similarities between PSZ in the granular samples and the PZS that developed along experimental faults made of solid rock that were sheared at similar conditions. The ultra-fine grains and extreme slip localization in these experiments are generally similar to ultra-cataclasites found in exhumed faults-zones, and the intensely pulverized gouge found in drilling across active faults.

Inferring fault rheology from low-frequency earthquakes on the San Andreas

USGS Publications Warehouse

Beeler, Nicholas M.; Thomas, Amanda; Bürgmann, Roland; Shelly, David R.

2013-01-01

Families of recurring low-frequency earthquakes (LFEs) within nonvolcanic tremor (NVT) on the San Andreas fault in central California show strong sensitivity to shear stress induced by the daily tidal cycle. LFEs occur at all levels of the tidal shear stress and are in phase with the very small, ~400 Pa, stress amplitude. To quantitatively explain the correlation, we use a model from the existing literature that assumes the LFE sources are small, persistent regions that repeatedly fail during shear of a much larger scale, otherwise aseismically creeping fault zone. The LFE source patches see tectonic loading, creep of the surrounding fault which may be modulated by the tidal stress, and direct tidal loading. If the patches are small relative to the surrounding creeping fault then the stressing is dominated by fault creep, and if patch failure occurs at a threshold stress, then the resulting seismicity rate is proportional to the fault creep rate or fault zone strain rate. Using the seismicity rate as a proxy for strain rate and the tidal shear stress, we fit the data with possible fault rheologies that produce creep in laboratory experiments at temperatures of 400 to 600°C appropriate for the LFE source depth. The rheological properties of rock-forming minerals for dislocation creep and dislocation glide are not consistent with the observed fault creep because strong correlation between small stress perturbations and strain rate requires perturbation on the order of the ambient stress. The observed tidal modulation restricts ambient stress to be at most a few kilopascal, much lower than rock strength. A purely rate dependent friction is consistent with the observations only if the product of the friction rate dependence and effective normal stress is ~ 0.5 kPa. Extrapolating the friction rate strengthening dependence of phyllosilicates (talc) to depth would require the effective normal stress to be ~50 kPa, implying pore pressure is lithostatic. If the LFE source is on the order of tens of meters, as required by the model, rate-weakening friction rate dependence (e.g., olivine) at 400 to 600°C requires that the minimum effective pressure at the LFE source is ~ 2.5 MPa.

Optical properties of breast tumor phantoms containing carbon nanotubes and nanohorns

PubMed Central

Sarkar, Saugata; Gurjarpadhye, Abhijit A.; Rylander, Christopher G.; Nichole Rylander, Marissa

2011-01-01

The degree by which optical properties of tumors are altered following introduction of carbon nanotubes (CNTs) of varying concentration and type is poorly understood, making it difficult to predict the impact of CNT inclusion on the photothermal response to laser therapies. Optical properties were measured of phantoms representative of breast tumor tissue incorporated with multiwalled carbon nanotubes (MWNTs), single-walled carbon nanotubes (SWNTs), and single-walled carbon nanohorns (SWNHs) of varying concentration (0.01–0.1 mg/ml). Tissue phantoms were made from sodium alginate (3 g/ml) incorporated with polystyrene microbeads (3 μm diam and 1 mg/ml) and talc-France powder (40 mg/ml). Absorption (μa) and reduced scattering (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}\\mu^\\prime _s\\end{equation*} \\end{document}μs′) coefficients of phantoms containing CNTs were determined by the inverse adding-doubling algorithm for the wavelength range of 400–1300 nm. Optical properties of phantoms without CNTs were in the range of μa = 1.04–0.06 mm−1 and \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}\\mu^\\prime _s\\end{equation*} \\end{document}μs′ = 0.05–0.07 mm−1 at a wavelength of 900 nm, which corresponds with published data for human breast tumor tissue. Incorporating MWNTs, SWNTs, and SWNHs in phantoms with a concentration of 0.1 mg/ml increased (μa) by 20- to 30-fold, 5- to 6-fold, and 9- to 14-fold, respectively, for the wavelength range of 800–1100 nm with minimal change in \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}\\mu^\\prime _s\\end{equation*} \\end{document}μs′ (1.2- to 1.3-fold). Introduction of CNTs into tissue phantoms increased absorption, providing a means to enhance photothermal therapy. PMID:21639564

Design and fabrication hazard stakes golf course polymeric foam material empty bunch (EFB) fiber reinforced

NASA Astrophysics Data System (ADS)

Zulfahmi; Syam, B.; Wirjosentono, B.

2018-02-01

A golf course with obstacles in the forms of water obstacle and lateral water obstacle marked with the stakes which are called golf course obstacle stake in this study. This study focused on the design and fabrication of the golf course obstacle stake with a solid cylindrical geometry using EFB fiber-reinforced polimeric foam composite materials. To obtain the EFB fiber which is free from fat content and other elements, EFB is soaked in the water with 1% (of the watre total volume) NaOH. The model of the mould designed is permanent mould that can be used for the further refabrication process. The mould was designed based on resin-compound paste materials with talc powder plus E-glass fiber to make the mould strong. The composition of polimeric foam materials comprised unsaturated resin Bqtn-Ex 157 (70%), blowing agent (10%), fiber (10%), and catalyst (10%). The process of casting the polimeric foam composit materials into the mould cavity should be at vertical casting position, accurate interval time of material stirring, and periodical casting. To find out the strength value of the golf course obstacle stake product, a model was made and simulated by using the software of Ansys workbench 14.0, an impact loading was given at the height of 400 mm and 460 mm with the variation of golf ball speed (USGA standard) v = 18 m/s, v = 35 m/s, v = 66.2 m/s, v = 70 m/s, and v = 78.2 m/s. The clarification showed that the biggest dynamic explicit loading impact of Fmax = 142.5 N at the height of 460 mm with the maximum golf ball speed of 78.2 m/s did not experience the hysteresis effect and inertia effect. The largest deformation area occurred at the golf ball speed v = 66.2 mm/s, that is 18.029 mm (time: 2.5514e-004) was only concentrated around the sectional area of contact point of impact, meaning that the golf course obstacle stakes made of EFB fiber-reinforced polymeric foam materials have the geometric functional strength that are able to absorb the energy of golf ball impact.

Ventilatory function in rubber processing workers: acute changes over the workshift.

PubMed Central

Governa, M; Comai, M; Valentino, M; Antonicelli, L; Rinaldi, F; Pisani, E

1987-01-01

When considering rubber tyre manufacturing from an occupational health viewpoint, three areas may be identified in which exposure to respirable materials are potentially harmful: the processing, curing, and talc areas. A study of the ventilatory function of the entire work force employed in the processing area in a rubber tyre manufacturing plant was undertaken to determine whether an acute reduction in lung function occurs over the course of their working shift (the plant worked a three shift system) and whether a chronic exposure to the occupational airborne contaminants causes permanent changes in lung function. The ventilatory function was measured at the worksite at the beginning and immediately after the end of the workshift. No evidence of chronic obstructive pulmonary disease was found and in most cases no significant decline in FEV1 was observed. Only one of the 79 individuals showed a moderate obstruction, measured by the ratio FEV1/FVC which gave the value of 0.55, with no variation over the shift. For non-smokers, the FVC, FEV1, and FEF25-75% were lower in those exposed for more than five years than in those exposed for five years or less. A similar pattern was also observed in the FVC and FEV1 of the smokers. None of these differences was statistically significant. Within each exposure group the pulmonary function of the smokers was lower than that of the non-smokers, but the only significant difference was found in the values of FEF25-75%. Only one man showed a decline in the FEV1/FVC ratio over the shift, but during each shift, a decrease in all the lung function tests was observed. The decrease was smallest during the first of the three shifts. These results are thought to support the hypothesis that there are acute adverse effects over an eight hour shift. Further investigations are needed to discover whether these acute changes in lung function result from a chemical stimulation or irritant receptors in the airways. PMID:3814549

DEVELOPMENT OF DEWATERING AIDS FOR MINERALS AND COAL FINES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roe-Hoam Yoon; Ramazan Asmatulu; Ismail Yildirim

2004-07-01

MCT has developed a suite of novel dewatering chemicals (or aids) that are designed to cause a decrease in the capillary pressures of the water trapped in a filter cake by (1) decreasing the surface tension of water, (2) increasing the contact angles of the particles to be dewatered, and (3) causing the particles to coagulate, all at the same time. The decrease in capillary pressure in turn causes an increase in the rate filtration, an increase in throughput, and a decrease in pressure drop requirement for filtration. The reagents are used frequently as blends of different chemicals in ordermore » to bring about the changes in all of the process variables noted above. The minerals and coal samples tested in the present work included copper sulfide, lead sulfide, zinc sulfide, kaolin clay, talc, and silica. The laboratory-scale test work included studies of reagent types, drying cycle times, cake thickness, slurry temperature, conditioning intensity and time, solid content, and reagent dosages. To better understand the mechanisms involved, fundamental studies were also conducted. These included the measurements of the contact angles of the particles to be dewatered (which are the measures of particle hydrophobicity) and the surface tensions of the filtrates produced from dewatering tests. The results of the laboratory-scale filtration experiments showed that the use of the novel dewatering aids can reduce the moistures of the filter cake by 30 to 50% over what can be achieved using no dewatering aids. In many cases, such high levels of moisture reductions are sufficient to obviate the needs for thermal drying, which is costly and energy intensive. Furthermore, the use of the novel dewatering aids cause a substantial increase in the kinetics of dewatering, which in turn results in increased throughput. As a result of these technological advantages, the novel dewatering aids have been licensed to Nalco, which is one of the largest mining chemicals companies of the world. At least one mineral company is currently using the technology in full-scale plant operation, which has resulted in the shutdown of a thermal dryer.« less

Stable isotopic compositions of carbonates from the Mesoproterozoic Bangemall Group, northwestern Australia

NASA Technical Reports Server (NTRS)

Buick, R.; Des Marais, D. J.; Knoll, A. H.

1995-01-01

Marine carbonate rocks from the Mesoproterozoic Bangemall Group of northwestern Australia show little deviation (+/-1.3%) in whole-rock delta 13C(carb)-values about a mean of -0.5%. This narrow range persists despite close sampling (every 10-20 m) through long sections (up to 2500 m) that are geographically widespread (up to 250 km apart), over many depositional environments (supralittoral to outer shelf), sediment sources (stromatolitic bioherms to detrital calcilutites) and rock types (pure limestones to dolomitic shales). The only major excursions from the norm seem related to unusual environmental or post-depositional processes, as they are correlated with large enrichments (to -3%) or depletions (to -16%) in 18O. Relatively heavy delta 13C-values, up to +2.5%, occur in a single bed of brecciated ferruginous dolostone at a single locality; these abnormal values may result from local evaporitic conditions. Limey and shaley nodular dolostones have delta 13C-values as low as -4.3%, probably caused by remineralization of organic matter during late and patchy dolomitization. Most notably, sharp negative excursions in delta 13C, up to -8.4%, occur in bleached kerogen-free rocks with mineral assemblages of dolomite + quartz + calcite +/- tremolite + talc, reflecting isotopic re-equilibration in thick metamorphic aureoles around dolerite intrusions. General environmental variations are minor, with delta 13C-values of peritidal facies tending to be slightly positive whereas those of subtidal facies are slightly negative. There are no strong secular trends, but subtle fluctuations within the range -2 to +l% can be correlated along the northwestern margin of the basin. This resembles the pattern seen in other Mesoproterozoic successions, but is markedly unlike the heavy background (> +5%) and extreme variations (up to l0%) in delta 13C evident in Neoproterozoic successions of similar thickness and environmental setting. Hence, in contrast to the Neoproterozoic, the global rate of organic carbon burial was probably fairly constant during deposition of the Bangemall Group, and perhaps generally during the Mesoproterozoic, as was the redox state of the atmosphere and hydrosphere.

Evaluation of the content of TiO2 nanoparticles in the coatings of chewing gums.

PubMed

Dudefoi, William; Terrisse, Hélène; Popa, Aurelian Florin; Gautron, Eric; Humbert, Bernard; Ropers, Marie-Hélène

2018-02-01

Titanium dioxide is a metal oxide used as a white pigment in many food categories, including confectionery. Due to differences in the mass fraction of nanoparticles contained in TiO 2 , the estimated intakes of TiO 2 nanoparticles differ by a factor of 10 in the literature. To resolve this problem, a better estimation of the mass of nanoparticles present in food products is needed. In this study, we focused our efforts on chewing gum, which is one of the food products contributing most to the intake of TiO 2 . The coatings of four kinds of chewing gum, where the presence of TiO 2 was confirmed by Raman spectroscopy, were extracted in aqueous phases. The extracts were analysed by transmission electron microscopy (TEM), X-ray diffraction, Fourier Transform Raman spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) to establish their chemical composition, crystallinity and size distribution. The coatings of the four chewing gums differ chemically from each other, and more specifically the amount of TiO 2 varies from one coating to another. TiO 2 particles constitute the entire coating of some chewing gums, whereas for others, TiO 2 particles are embedded in an organic matrix and/or mixed with minerals like calcium carbonate, talc, or magnesium silicate. We found 1.1 ± 0.3 to 17.3 ± 0.9 mg TiO 2 particles per piece of chewing gum, with a mean diameter of 135 ± 42 nm. TiO 2 nanoparticles account for 19 ± 4% of all particles, which represents a mass fraction of 4.2 ± 0.1% on average. The intake of nanoparticles is thus highly dependent on the kind of chewing gum, with an estimated range extending from 0.04 ± 0.01 to 0.81 ± 0.04 mg of nano-TiO 2 per piece of chewing gum. These data should serve to refine the exposure scenario.