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Sample records for eesti arstide tga

  1. Trace Gas Analyzer (TGA) program

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The design, fabrication, and test of a breadboard trace gas analyzer (TGA) is documented. The TGA is a gas chromatograph/mass spectrometer system. The gas chromatograph subsystem employs a recirculating hydrogen carrier gas. The recirculation feature minimizes the requirement for transport and storage of large volumes of carrier gas during a mission. The silver-palladium hydrogen separator which permits the removal of the carrier gas and its reuse also decreases vacuum requirements for the mass spectrometer since the mass spectrometer vacuum system need handle only the very low sample pressure, not sample plus carrier. System performance was evaluated with a representative group of compounds.

  2. Transposition of the Greater Arteries (TGA)

    MedlinePlus

    ... rest of the body. According to the National Heart, Lung, and Blood Institute (NHLBI), TGA affects roughly 5 out of every 10,000 babies. The defect is found more frequently in Caucasians. Untreated, more than 50% of infants with transposition will die in the first month ...

  3. TGA and DTA studies of solvent-exchanged gels

    SciTech Connect

    Leeb, K.; Durakpasa, H.; Breiter, M.W.

    1994-12-31

    Sols were prepared in the system TMOS:H{sub 2}O:SOLV:HCl with molar ratios of 1:4:3:0.0005 for SOLV = MEOH, ETOH and DMF. The gelation and aging of these sols took place in cuvettes covered by parafilm. The gels were removed from the cuvettes 14 days after gelation. Solvent exchange was carried out in each of the three solvents for a period of 14 days. Starting with fresh solvent, the exchange was repeated three times. TGA and DTA curves were taken with pieces of the original gels and of gels after the 2nd and 3rd solvent exchange. The TGA curves display a considerable weight loss in the temperature range of solvent evaporation. A small step is observed at higher temperatures if MEOH or ETOH represent the exchange solvent. The DTA curves allow a distinction what mixtures of solvents are present. The effectiveness of the solvent exchange can be evaluated.

  4. Arabidopsis basic leucine-zipper transcription factors TGA9 and TGA10 interact with floral glutaredoxins ROXY1 and ROXY2 and are redundantly required for anther development.

    PubMed

    Murmu, Jhadeswar; Bush, Michael J; DeLong, Catherine; Li, Shutian; Xu, Mingli; Khan, Madiha; Malcolmson, Caroline; Fobert, Pierre R; Zachgo, Sabine; Hepworth, Shelley R

    2010-11-01

    ROXY1 and ROXY2 are CC-type floral glutaredoxins with redundant functions in Arabidopsis (Arabidopsis thaliana) anther development. We show here that plants lacking the basic leucine-zipper transcription factors TGA9 and TGA10 have defects in male gametogenesis that are strikingly similar to those in roxy1 roxy2 mutants. In tga9 tga10 mutants, adaxial and abaxial anther lobe development is differentially affected, with early steps in anther development blocked in adaxial lobes and later steps affected in abaxial lobes. Distinct from roxy1 roxy2, microspore development in abaxial anther lobes proceeds to a later stage with the production of inviable pollen grains contained within nondehiscent anthers. Histological analysis shows multiple defects in the anther dehiscence program, including abnormal stability and lignification of the middle layer and defects in septum and stomium function. Compatible with these defects, TGA9 and TGA10 are expressed throughout early anther primordia but resolve to the middle and tapetum layers during meiosis of pollen mother cells. Several lines of evidence suggest that ROXY promotion of anther development is mediated in part by TGA9 and TGA10. First, TGA9 and TGA10 expression overlaps with ROXY1/2 during anther development. Second, TGA9/10 and ROXY1/2 operate downstream of SPOROCYTELESS/NOZZLE, where they positively regulate a common set of genes that contribute to tapetal development. Third, TGA9 and TGA10 directly interact with ROXY proteins in yeast and in plant cell nuclei. These findings suggest that activation of TGA9/10 transcription factors by ROXY-mediated modification of cysteine residues promotes anther development, thus broadening our understanding of how redox-regulated TGA factors function in plants.

  5. In silico cloning and characterization of the TGA (TGACG MOTIF-BINDING FACTOR) transcription factors subfamily in Carica papaya.

    PubMed

    Idrovo Espín, Fabio Marcelo; Peraza-Echeverria, Santy; Fuentes, Gabriela; Santamaría, Jorge M

    2012-05-01

    The TGA transcription factors belong to the subfamily of bZIP group D that play a major role in disease resistance and development. Most of the TGA identified in Arabidopsis interact with the master regulator of SAR, NPR1 that controls the expression of PR genes. As a first approach to determine the possible involvement of these transcription factors in papaya defense, we characterized Arabidopsis TGA orthologs from the genome of Carica papaya cv. SunUp. Six orthologs CpTGA1 to CpTGA6, were identified. The predicted CpTGA proteins were highly similar to AtTGA sequences and probably share the same DNA binding properties and transcriptional regulation features. The protein sequences alignment evidenced the presence of conserved domains, characteristic of this group of transcription factors. The phylogeny showed that CpTGA evolved into three different subclades associated with defense and floral development. This is the first report of basal expression patterns assessed by RT-PCR, from the whole subfamily of CpTGA members in different tissues from papaya cv. Maradol mature plants. Overall, CpTGA1, CpTGA3 CpTGA6 and CpTGA4 showed a basal expression in all tissues tested; CpTGA2 expressed strongly in all tissues except in petioles while CpTGA5 expressed only in petals and to a lower extent in petioles. Although more detailed studies in anthers and other floral structures are required, we suggest that CpTGA5 might be tissue-specific, and it might be involved in papaya floral development. On the other hand, we report here for the first time, the expression of the whole family of CpTGA in response to salicylic acid (SA). The expression of CpTGA3, CpTGA4 and CpTGA6 increased in response to SA, what would suggest its involvement in the SAR response in papaya.

  6. Facts about dextro-Transposition of the Great Arteries (d-TGA)

    MedlinePlus

    ... ASD may not have as severe symptoms as infants whose hearts don’t have any mixing of blood. Infants with d-TGA can have a bluish looking ... if it is beating too fast. If the heart is beating too slowly, a pacemaker can be used. Infants who have these surgeries are not cured; they ...

  7. Pyrolysis and gasification of typical components in wastes with macro-TGA.

    PubMed

    Meng, Aihong; Chen, Shen; Long, Yanqiu; Zhou, Hui; Zhang, Yanguo; Li, Qinghai

    2015-12-01

    The pyrolysis and gasification of typical components of solid waste, cellulose, hemicellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC) and poly(ethylene terephthalate) (PET) were performed and compared in a macro thermogravimetric analyzer (macro-TGA). Three model biomasses, poplar stem, orange peel and Chinese cabbage, were applied to pyrolysis and gasification simulation by their components based on TG curves. Compared to those from TGA, peaks temperature of the differential thermogravimetric (DTG) curves of each samples pyrolysis on macro-TGA delayed 30-55°C due to heat transferring effect. CO2 promoted the thermal decomposition of hemicellulose, lignin, starch, pectin and model biomasses significantly by Boudouard reaction, and enhanced slightly the decomposition of PET. The activation energy (AE) of biomass components pyrolysis on macro-TGA was 167-197 kJ/mol, while that of plastic samples was 185-235 kJ/mol. The activation energy of 351-377 kJ/mol was corresponding to the Boudouard reaction in CO2 gasification. All overlap ratios in pseudo-components simulation were higher than 0.98 to indicate that pseudo-components model could be applied to both pyrolysis and CO2 gasification, and the mass fractions of components derived from pyrolysis and gasification were slightly different but not brought in obvious difference in simulating curves when they were applied across.

  8. Evaporation of HD Droplets From Nonporous, Inert Surfaces in TGA Microbalance Wind Tunnels

    DTIC Science & Technology

    2008-09-01

    2007 4. TITLE AND SUBTITLE Evaporation of HD Droplets from Nonporous, Inert Surfaces in TGA Microbalancc Wind Tunnels 5a. CONTRACT NUMBER DAAD13...hr (lightly swirled on a rotating plateau). Then, the glass was rinsed with dematerialized water and dried (using appropriate fat-free non-felting

  9. Quantitative detection of powdered activated carbon in wastewater treatment plant effluent by thermogravimetric analysis (TGA).

    PubMed

    Krahnstöver, Therese; Plattner, Julia; Wintgens, Thomas

    2016-09-15

    For the elimination of potentially harmful micropollutants, powdered activated carbon (PAC) adsorption is applied in many wastewater treatment plants (WWTP). This holds the risk of PAC leakage into the WWTP effluent and desorption of contaminants into natural water bodies. In order to assess a potential PAC leakage, PAC concentrations below several mg/L have to be detected in the WWTP effluent. None of the methods that are used for water analysis today are able to differentiate between activated carbon and solid background matrix. Thus, a selective, quantitative and easily applicable method is still needed for the detection of PAC residues in wastewater. In the present study, a method was developed to quantitatively measure the PAC content in wastewater by using filtration and thermogravimetric analysis (TGA), which is a well-established technique for the distinction between different solid materials. For the sample filtration, quartz filters with a temperature stability up to 950 °C were used. This allowed for sensitive and well reproducible measurements, as the TGA was not affected by the presence of the filter. The sample's mass fractions were calculated by integrating the mass decrease rate obtained by TGA in specific, clearly identifiable peak areas. A two-step TGA heating method consisting of N2 and O2 atmospheres led to a good differentiation between PAC and biological background matrix, thanks to the reduction of peak overlapping. A linear correlation was found between a sample's PAC content and the corresponding peak areas under N2 and O2, the sample volume and the solid mass separated by filtration. Based on these findings, various wastewater samples from different WWTPs were then analyzed by TGA with regard to their PAC content. It was found that, compared to alternative techniques such as measurement of turbidity or total suspended solids, the newly developed TGA method allows for a quantitative and selective detection of PAC concentrations down to 0

  10. Thermal degradation studies and kinetic modeling of cardoon (Cynara cardunculus) pyrolysis using thermogravimetric analysis (TGA).

    PubMed

    Damartzis, Th; Vamvuka, D; Sfakiotakis, S; Zabaniotou, A

    2011-05-01

    A key element in the design of sustainable pyrolysis processes is the thermal degradation kinetics of biomass. In this work, pyrolysis tests for cardoon (Cynara carduculus) stems and leaves were performed in a non-isothermal thermogravimetric analyzer (TGA) in order to determine the thermal degradation behavior of both stems and leaves. The kinetic parameters of the process were evaluated using three different kinetic models, the independent parallel reaction model, KAS and OFW iso-conversional model. Good agreement with the experimental TGA data was observed for all models, the best being with the independent parallel reaction model. A variance in the activation energy with conversion was observed when the KAS and OFW models were employed, which reveals that the pyrolysis of cardoon progresses through more complex and multi-step kinetics.

  11. Aqueous synthesis and characterization of TGA-capped CdSe quantum dots at freezing temperature.

    PubMed

    Sun, Qizhuang; Fu, Shasha; Dong, Tingmei; Liu, Shuxian; Huang, Chaobiao

    2012-07-11

    CdSe quantum dots (QDs) have traditionally been synthesized in organic phase and then transferred to aqueous solution by functionalizing their surface with silica, polymers, short-chain thiol ligands, or phospholipid micelles. However, a drastic increase in the hydrodynamic size and biotoxicity of QDs may hinder their biomedical applications. In this paper, the TGA-capped CdSe QDs are directly synthesized in aqueous phase at freezing temperature, and they prove to possess high QY (up to 14%).

  12. The role of teosinte glume architecture (tga1) in coordinated regulation and evolution of grass glumes and inflorescence axes.

    PubMed

    Preston, Jill C; Wang, Huai; Kursel, Lisa; Doebley, John; Kellogg, Elizabeth A

    2012-01-01

    • Hardened floral bracts and modifications to the inflorescence axis of grasses have been hypothesized to protect seeds from predation and/or aid seed dispersal, and have evolved multiple times independently within the family. Previous studies have demonstrated that mutations in the maize (Zea mays ssp. mays) gene teosinte glume architecture (tga1) underlie a reduction in hardened structures, yielding free fruits that are easy to harvest. It remains unclear whether the causative mutation(s) occurred in the cis-regulatory or protein-coding regions of tga1, and whether similar mutations in TGA1-like genes can explain variation in the dispersal unit in related grasses. • To address these questions TGA1-like genes were cloned and sequenced from a number of grasses and analyzed phylogenetically in relation to morphology; protein expression was investigated by immunolocalization. • TGA1-like proteins were expressed throughout the spikelet in the early development of all grasses, and throughout the flower of the grass relative Joinvillea. Later in development, expression patterns differed between Tripsacum dactyloides, maize and teosinte (Z. mays ssp. parviglumis). • These results suggest an ancestral role for TGA1-like genes in early spikelet development, but do not support the hypothesis that TGA1-like genes have been repeatedly modified to affect glume and inflorescence axis diversification.

  13. Thermal characterization and model free kinetics of aged epoxies and foams using TGA and DSC methods.

    SciTech Connect

    Cordaro, Joseph Gabriel; Kruizenga, Alan Michael; Nissen, April

    2013-10-01

    Two classes of materials, poly(methylene diphenyl diisocyanate) or PMDI foam, and cross-linked epoxy resins, were characterized using thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), to help understand the effects of aging and %E2%80%9Cbake-out%E2%80%9D. The materials were evaluated for mass loss and the onset of decomposition. In some experiments, volatile materials released during heating were analyzed via mass spectroscopy. In all, over twenty materials were evaluated to compare the mass loss and onset temperature for decomposition. Model free kinetic (MFK) measurements, acquired using variable heating rate TGA experiments, were used to calculate the apparent activation energy of thermal decomposition. From these compiled data the effects of aging, bake-out, and sample history on the thermal stability of materials were compared. No significant differences between aged and unaged materials were detected. Bake-out did slightly affect the onset temperature of decomposition but only at the highest bake-out temperatures. Finally, some recommendations for future handling are made.

  14. TGA-DTA and chemical composition study of raw material of Bikaner region for electrical porcelain

    NASA Astrophysics Data System (ADS)

    Tak, S. K.; Shekhawat, M. S.; Mangal, R.

    2013-06-01

    Porcelains are vitrified and a fine grained ceramic product, used either glazed or unglazed and is often manufactured from a tri-axial body mix of clays, quartz and alkaline feldspar. Physical properties associated with porcelain include those of permeability, high strength, hardness, glassiness, durability, whiteness, translucence, resonance, brittleness, high resistance to the passage of electricity, high resistance to thermal shock and high elasticity[1,2]. Porcelain insulators are made from three raw materials; clay; feldspar and quartz. For porcelain manufacture the clay is categorized in two groups; ball clay and kaolin, each of which plays an important role, either in the preparation of the product or in the properties of the finished products. The following research highlights the importance that suits these materials for their contributions to the final properties of the product. Keeping this view a TGA-DTA and chemical composition of these raw materials were observed and these materials are found suitable for production of Electrical Porcelain.

  15. Motor skill learning and offline-changes in TGA patients with acute hippocampal CA1 lesions.

    PubMed

    Döhring, Juliane; Stoldt, Anne; Witt, Karsten; Schönfeld, Robby; Deuschl, Günther; Born, Jan; Bartsch, Thorsten

    2017-04-01

    Learning and the formation of memory are reflected in various memory systems in the human brain such as the hippocampus based declarative memory system and the striatum-cortex based system involved in motor sequence learning. It is a matter of debate how both memory systems interact in humans during learning and consolidation and how this interaction is influenced by sleep. We studied the effect of an acute dysfunction of hippocampal CA1 neurons on the acquisition (on-line condition) and off-line changes of a motor skill in patients with a transient global amnesia (TGA). Sixteen patients (68 ± 4.4 yrs) were studied in the acute phase and during follow-up using a declarative and procedural test, and were compared to controls. Acute TGA patients displayed profound deficits in all declarative memory functions. During the acute amnestic phase, patients were able to acquire the motor skill task reflected by increasing finger tapping speed across the on-line condition, albeit to a lesser degree than during follow-up or compared to controls. Retrieval two days later indicated a greater off-line gain in motor speed in patients than controls. Moreover, this gain in motor skill performance was negatively correlated to the declarative learning deficit. Our results suggest a differential interaction between procedural and declarative memory systems during acquisition and consolidation of motor sequences in older humans. During acquisition, hippocampal dysfunction attenuates fast learning and thus unmasks the slow and rigid learning curve of striatum-based procedural learning. The stronger gains in the post-consolidation condition in motor skill in CA1 lesioned patients indicate a facilitated consolidation process probably occurring during sleep, and suggest a competitive interaction between the memory systems. These findings might be a reflection of network reorganization and plasticity in older humans and in the presence of CA1 hippocampal pathology.

  16. The N-Terminus of the Floral Arabidopsis TGA Transcription Factor PERIANTHIA Mediates Redox-Sensitive DNA-Binding

    PubMed Central

    Gutsche, Nora; Zachgo, Sabine

    2016-01-01

    The Arabidopsis TGA transcription factor (TF) PERIANTHIA (PAN) regulates the formation of the floral organ primordia as revealed by the pan mutant forming an abnormal pentamerous arrangement of the outer three floral whorls. The Arabidopsis TGA bZIP TF family comprises 10 members, of which PAN and TGA9/10 control flower developmental processes and TGA1/2/5/6 participate in stress-responses. For the TGA1 protein it was shown that several cysteines can be redox-dependently modified. TGA proteins interact in the nucleus with land plant-specific glutaredoxins, which may alter their activities posttranslationally. Here, we investigated the DNA-binding of PAN to the AAGAAT motif under different redox-conditions. The AAGAAT motif is localized in the second intron of the floral homeotic regulator AGAMOUS (AG), which controls stamen and carpel development as well as floral determinacy. Whereas PAN protein binds to this regulatory cis-element under reducing conditions, the interaction is strongly reduced under oxidizing conditions in EMSA studies. The redox-sensitive DNA-binding is mediated via a special PAN N-terminus, which is not present in other Arabidopsis TGA TFs and comprises five cysteines. Two N-terminal PAN cysteines, Cys68 and Cys87, were shown to form a disulfide bridge and Cys340, localized in a C-terminal putative transactivation domain, can be S-glutathionylated. Comparative land plant analyses revealed that the AAGAAT motif exists in asterid and rosid plant species. TGA TFs with N-terminal extensions of variable length were identified in all analyzed seed plants. However, a PAN-like N-terminus exists only in the rosids and exclusively Brassicaceae homologs comprise four to five of the PAN N-terminal cysteines. Redox-dependent modifications of TGA cysteines are known to regulate the activity of stress-related TGA TFs. Here, we show that the N-terminal PAN cysteines participate in a redox-dependent control of the PAN interaction with a highly conserved

  17. Is some better than none: are TEG and TGA profiles different in severe FVIII-deficient patients with inhibitors?

    PubMed

    Salinas, V; Carmona, R; Mohammed, B M; Martin, E J; Brophy, D F; Young, G

    2015-05-01

    Severe factor VIII (FVIII)-deficient patients with and without FVIII inhibitors cannot be distinguished using FVIII levels. The FVIII assay is sensitive to detect factor levels below 1%. While severe FVIII-deficient, non-inhibitor patients have FVIII < 1%, they may retain unmeasurable residual factor activity. In contrast, inhibitor patients have a FVIII antibody that presumably fully eliminates FVIII activity. It is unknown whether thromboelastography (TEG) and thrombin generation assay (TGA) can differentiate between patients with FVIII < 1% with and without the presence of FVIII inhibitors. The primary objective was to discern whether TEG and TGA could differentiate between severe FVIII-deficient patients with and without the presence of FVIII inhibitors. A secondary objective was to correlate TEG and TGA to annualized bleeding rates. This observational study performed TEG and TGA in healthy volunteers (N = 15), severe FVIII-deficient (N = 15) and severe FVIII-deficient patients with inhibitors (N = 15). Kaolin-activated TEG was better at differentiating reaction time (31.3 vs. 120 min respectively, P = 0.004) and kinetics time (6.1 vs. 23.1 min respectively, P = 0.028) between the non-inhibitor and inhibitor patients. TEG activated by tissue factor in plasma-containing corn trypsin inhibitor failed to differentiate groups. The TGA failed to differentiate peak thrombin, endogenous thrombin potential and lag time between groups. There was no correlation between TEG and TGA with annualized bleeding rates. Kaolin-activated TEG, but not TGA, differentiated between severe FVIII-deficient patients with and without inhibitors. These assays did not find a correlation to annualized bleeding rate.

  18. General Detoxification and Stress Responses Are Mediated by Oxidized Lipids through TGA Transcription Factors in Arabidopsis[W

    PubMed Central

    Mueller, Stefan; Hilbert, Beate; Dueckershoff, Katharina; Roitsch, Thomas; Krischke, Markus; Mueller, Martin J.; Berger, Susanne

    2008-01-01

    12-oxo-phytodienoic acid and several phytoprostanes are cyclopentenone oxylipins that are formed via the enzymatic jasmonate pathway and a nonenzymatic, free radical–catalyzed pathway, respectively. Both types of cyclopentenone oxylipins induce the expression of genes related to detoxification, stress responses, and secondary metabolism, a profile clearly distinct from that of the cyclopentanone jasmonic acid. Microarray analyses revealed that 60% of the induction by phytoprostanes and 30% of the induction by 12-oxo-phytodienoic acid was dependent on the TGA transcription factors TGA2, TGA5, and TGA6. Moreover, treatment with phytoprostanes and 12-oxo-phytodienoic acid inhibited cell division and root growth, a property also shared by jasmonic acid. Besides being potent signals, cyclopentenones and other lipid peroxidation products are reactive electrophiles that can covalently bind to and damage proteins. To this end, we show that at least two of the induced detoxification enzymes efficiently metabolize cyclopentenones in vitro. Accumulation of two of these metabolites was detectable during Pseudomonas infection. The cyclopentenone oxylipin gene induction profile resembles the defense response induced by a variety of lipophilic xenobiotics. Hence, oxidized lipids may activate chemosensory mechanisms of a general broad-spectrum detoxification network involving TGA transcription factors. PMID:18334669

  19. Suppression of TGA Mutations in the Bacillus subtilis spoIIR Gene by prfB Mutations

    PubMed Central

    Karow, Margaret L.; Rogers, Elizabeth J.; Lovett, Paul S.; Piggot, Patrick J.

    1998-01-01

    An unexpectedly high proportion of TGA nonsense mutations was obtained in a collection of chemically induced mutations in the spoIIR locus of Bacillus subtilis. Of 11 different mutations obtained, TGA mutations were found in four codons, whereas only three codons yielded missense mutations. Six suppressors of the TGA mutations were isolated, and five of the suppressing mutations were mapped to the prfB gene encoding protein release factor 2. These are the first mutations shown to map to the B. subtilis prfB locus. The sequence of the prfB gene was completed, and two revisions of the published sequence were made. The five prfB mutations also resulted in suppression of the catA86-TGA mutation to between 19 and 54% of the expression of catA86+, compared to the readthrough level of 6% in the prfB+ strain. N-terminal sequencing of suppressed catA86-TGA-specified protein demonstrated that the amino acid inserted at UGA because of the prfB1 mutations was tryptophan. PMID:9696765

  20. Analysis of the combustion and pyrolysis of dried sewage sludge by TGA and MS.

    PubMed

    Magdziarz, Aneta; Werle, Sebastian

    2014-01-01

    In this study, the combustion and pyrolysis processes of three sewage sludge were investigated. The sewage sludge came from three wastewater treatment plants. Proximate and ultimate analyses were performed. The thermal behaviour of studied sewage sludge was investigated by thermogravimetric analysis with mass spectrometry (TGA-MS). The samples were heated from ambient temperature to 800 °C at a constant rate 10 °C/min in air (combustion process) and argon flows (pyrolysis process). The thermal profiles presented in form of TG/DTG curves were comparable for studied sludges. All TG/DTG curves were divided into three stages. The main decomposition of sewage sludge during the combustion process took place in the range 180-580 °C with c.a. 70% mass loss. The pyrolysis process occurred in lower temperature but with less mass loss. The evolved gaseous products (H2, CH4, CO2, H2O) from the decomposition of sewage sludge were identified on-line.

  1. Methods of Measuring Vapor Pressures of Lubricants With Their Additives Using TGA and/or Microbalances

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.; Miller, Michael K.; Montoya, Alex F.

    1996-01-01

    The life of a space system may be critically dependent on the lubrication of some of its moving parts. The vapor pressure, the quantity of the available lubricant, the temperature and the exhaust venting conductance passage are important considerations in the selection and application of a lubricant. In addition, the oil additives employed to provide certain properties of low friction, surface tension, antioxidant and load bearing characteristics, are also very important and need to be known with regard to their amounts and vapor pressures. This paper reports on the measurements and analyses carried out to obtain those parameters for two often employed lubricants, the Apiezon(TM)-C and the Krytox(TM) AB. The measurements were made employing an electronic microbalance and a thermogravimetric analyzer (TGA) modified to operate in a vacuum. The results have been compared to other data on these oils when available. The identification of the mass fractions of the additives in the oil and their vapor pressures as a function of the temperature were carried out. These may be used to estimate the lubricant life given its quantity and the system vent exhaust conductance. It was found that the Apiezon(TM)-C has three main components with different rates of evaporation while the Krytox(TM) did not indicate any measurable additive.

  2. Thermal decomposition of dolomite under CO2: insights from TGA and in situ XRD analysis.

    PubMed

    Valverde, Jose Manuel; Perejon, Antonio; Medina, Santiago; Perez-Maqueda, Luis A

    2015-11-28

    Thermal decomposition of dolomite in the presence of CO2 in a calcination environment is investigated by means of in situ X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The in situ XRD results suggest that dolomite decomposes directly at a temperature around 700 °C into MgO and CaO. Immediate carbonation of nascent CaO crystals leads to the formation of calcite as an intermediate product of decomposition. Subsequently, decarbonation of this poorly crystalline calcite occurs when the reaction is thermodynamically favorable and sufficiently fast at a temperature depending on the CO2 partial pressure in the calcination atmosphere. Decarbonation of this dolomitic calcite occurs at a lower temperature than limestone decarbonation due to the relatively low crystallinity of the former. Full decomposition of dolomite leads also to a relatively low crystalline CaO, which exhibits a high reactivity as compared to limestone derived CaO. Under CO2 capture conditions in the Calcium-Looping (CaL) process, MgO grains remain inert yet favor the carbonation reactivity of dolomitic CaO especially in the solid-state diffusion controlled phase. The fundamental mechanism that drives the crystallographic transformation of dolomite in the presence of CO2 is thus responsible for its fast calcination kinetics and the high carbonation reactivity of dolomitic CaO, which makes natural dolomite a potentially advantageous alternative to limestone for CO2 capture in the CaL technology as well as SO2in situ removal in oxy-combustion fluidized bed reactors.

  3. Detecting buried archaeological soils with TGA in an agricultural terrace setting in Northern Calabria, Italy

    NASA Astrophysics Data System (ADS)

    Koster, K.; Guttmann-Bond, E.; Kluiving, S.; van Leusen, M.

    2012-04-01

    Agricultural terraces are geomorphologic features created by humans. These structures protect farming land by reducing soil erosion, they collect water in their hydrological infrastructure, and preserve crops and vegetation. Their construction could however negatively affect underlying soils and archaeology present in those soils. However, if a terrace is constructed on a hill slope without destroying the underlying soil, the agricultural terrace could create a stable environment in regard to erosion, and preserve the underlying soil and potential archaeological remains in it. In order to detect soils within agricultural terraces in Northern-Calabria, Italy, Thermogravimetric Analysis (TGA) was performed on exposures of four agricultural terraces, two agricultural fields in a non-terraced setting and five natural geomorphological features. Results are the detection of a buried soil horizon which contains archaeological remains dating from the Hellenistic period 60 cm below the surface of an agricultural terrace, and a buried soil horizon which contains archaeological remains dating from the Hellenistic period at the interface of an agricultural field and a river valley. Both soil horizons were indentified by an increase in organic components, and a decrease in calcium carbonates relative to their surrounding context. Conclusions are that the construction of agricultural terraces and fields does not necessarily lead to the destruction of underlying soils. This could open new doors for archaeological field investigations in agricultural areas in southern Italy. This study was conducted as part of the Raganello Archaeological Project of the Groningen Institute of Archaeology, Rijks Universiteit Groningen, in collaboration with the Institute for Geo- and Bioarchaeology at the VU University Amsterdam.

  4. Some critical aspects of FT-IR, TGA, powder XRD, EDAX and SEM studies of calcium oxalate urinary calculi.

    PubMed

    Joshi, Vimal S; Vasant, Sonal R; Bhatt, J G; Joshi, Mihir J

    2014-06-01

    Urinary calculi constitute one of the oldest afflictions of humans as well as animals, which are occurring globally. The calculi vary in shape, size and composition, which influence their clinical course. They are usually of the mixed-type with varying percentages of the ingredients. In medical management of urinary calculi, either the nature of calculi is to be known or the exact composition of calculi is required. In the present study, two selected calculi were recovered after surgery from two different patients for detailed examination and investigated by using Fourier-Transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy and energy dispersive analysis of X-rays (EDAX) techniques. The study demonstrated that the nature of urinary calculi and presence of major phase in mixed calculi could be identified by FT-IR, TGA and powder XRD, however, the exact content of various elements could be found by EDAX only.

  5. Antibacterial potential of rutin conjugated with thioglycolic acid capped cadmium telluride quantum dots (TGA-CdTe QDs)

    NASA Astrophysics Data System (ADS)

    Ananth, Devanesan Arul; Rameshkumar, Angappan; Jeyadevi, Ramachandran; Jagadeeswari, Sivanadanam; Nagarajan, Natarajan; Renganathan, Rajalingam; Sivasudha, Thilagar

    2015-03-01

    Quantum dots not only act as nanocarrier but also act as stable and resistant natural fluorescent bio markers used in various in vitro and in vivo photolabelling and biological applications. In this study, the antimicrobial potential of TGA-CdTe QDs and commercial phenolics (rutin and caffeine) were investigated against Escherichiacoli. UV absorbance and fluorescence quenching study of TGA-CdTe QDs with rutin and caffeine complex was measured by spectroscopic technique. QDs-rutin conjugate exhibited excellent quenching property due to the -OH groups present in the rutin structure. But the same time caffeine has not conjugated with QDs because of lacking of -OH group in its structure. Photolabelling of E. coli with QDs-rutin and QDs-caffeine complex was analyzed by fluorescent microscopic method. Microbe E. coli cell membrane damage was assessed by atomic force (AFM) and confocal microscopy. Based on the results obtained, it is suggested that QDs-rutin conjugate enhance the antimicrobial activity more than the treatment with QDs, rutin and caffeine alone.

  6. Determination of microplastic polyethylene (PE) and polypropylene (PP) in environmental samples using thermal analysis (TGA-DSC).

    PubMed

    Majewsky, Marius; Bitter, Hajo; Eiche, Elisabeth; Horn, Harald

    2016-10-15

    Microplastics are increasingly detected in the environment and the consequences on water resources and ecosystems are not clear to date. The present study provides a cost-effective and straightforward method to determine the mass concentrations of polymer types using thermal analysis. Characteristic endothermic phase transition temperatures were determined for seven plastic polymer types using TGA-DSC. Based on that, extracts from wastewater samples were analyzed. Results showed that among the studied polymers, only PE and PP could be clearly identified, while the phase transition signals of the other polymers largely overlap each other. Subsequently, calibration curves were run for PE and PP for qualitative measurements. 240 and 1540mg/m(3) of solid material (12µm to 1mm) was extracted from two wastewater effluent samples of a municipal WWTP of which 34% (81mg/m(3)) and 17% (257mg/m(3)) could be assigned to PE, while PP was not detected in any of the samples. The presented application of TGA-DSC provides a complementary or alternative method to FT-IR analyses for the determination of PE and PP in environmental samples.

  7. Interaction of TGA@CdTe Quantum Dots with an Extracellular Matrix of Haematococcus pluvialis Microalgae Detected Using Surface-Enhanced Raman Spectroscopy (SERS).

    PubMed

    Cepeda-Pérez, Elisa; Aguilar-Hernández, Iris; López-Luke, Tzarara; Piazza, Valeria; Carriles, Ramón; Ornelas-Soto, Nancy; de la Rosa, Elder

    2016-09-01

    The present study reports the localization and interaction of thioglycolic acid (TGA) capped CdTe quantum dots (TGA@CdTe QDs) within the extracellular matrix (ECM) of Haematococcus pluvialis (Chlorophyceae) microalgae (HPM) after an incubation period of 5 min. Changes in the Raman spectrum of HPM induced by the adsorption of the TGA@CdTe QDs are successfully found by using naked gold anisotropic structures as nano-sensors for surface-enhanced Raman scattering (SERS effect). Raman spectroscopy results show that TGA@CdTe QDs interact with the biomolecules present in the ECM. Sample preparation and characterization by complementary techniques such as confocal and electron microscopy are also used to confirm the presence and localization of the nanoparticles in the algae. This research shows new evidence on early accumulation of QDs in plant cells and would further improve our understanding about their environmental impact.

  8. Fluorescence Determination of Warfarin Using TGA-capped CdTe Quantum Dots in Human Plasma Samples.

    PubMed

    Dehbozorgi, A; Tashkhourian, J; Zare, S

    2015-11-01

    In this study, some effort has been performed to provide low temperature, less time consuming and facile routes for the synthesis of CdTe quantum dots using ultrasound and water soluble capping agent thioglycolic acid. TGA-capped CdTe quantum dots were characterized through x-ray diffraction, transmission electron microscopy, Fourier transform infrared, ultraviolet-visible and fluorescence spectroscopy. The prepared quantum dots were used for warfarin determination based on the quenching of the fluorescence intensity in aqueous solution. Under the optimized conditions, the linear range of quantum dots fluorescence intensity versus the concentration of warfarin was 0.1-160.0 μM, with the correlation coefficient of 0.9996 and a limit of detection of 77.5 nM. There was no interference to coexisting foreign substances. The selectivity of the sensor was also tested and the results show that the developed method possesses a high selectivity for warfarin.

  9. Combustion characteristics of Malaysian oil palm biomass, sub-bituminous coal and their respective blends via thermogravimetric analysis (TGA).

    PubMed

    Idris, Siti Shawalliah; Rahman, Norazah Abd; Ismail, Khudzir

    2012-11-01

    The combustion characteristics of Malaysia oil palm biomass (palm kernel shell (PKS), palm mesocarp fibre (PMF) and empty fruit bunches (EFB)), sub-bituminous coal (Mukah Balingian) and coal/biomass blends via thermogravimetric analysis (TGA) were investigated. Six weight ratios of coal/biomass blends were prepared and oxidised under dynamic conditions from temperature 25 to 1100°C at four heating rates. The thermogravimetric analysis demonstrated that the EFB and PKS evolved additional peak besides drying, devolatilisation and char oxidation steps during combustion. Ignition and burn out temperatures of blends were improved in comparison to coal. No interactions were observed between the coal and biomass during combustion. The apparent activation energy during this process was evaluated using iso-conversional model free kinetics which resulted in highest activation energy during combustion of PKS followed by PMF, EFB and MB coal. Blending oil palm biomass with coal reduces the apparent activation energy value.

  10. Technical basis for the reduction of the maximum temperature TGA-MS analysis of oxide samples from the 3013 destructive examination program

    SciTech Connect

    Scogin, J. H.

    2016-03-24

    Thermogravimetric analysis with mass spectroscopy of the evolved gas (TGA-MS) is used to quantify the moisture content of materials in the 3013 destructive examination (3013 DE) surveillance program. Salts frequently present in the 3013 DE materials volatilize in the TGA and condense in the gas lines just outside the TGA furnace. The buildup of condensate can restrict the flow of purge gas and affect both the TGA operations and the mass spectrometer calibration. Removal of the condensed salts requires frequent maintenance and subsequent calibration runs to keep the moisture measurements by mass spectroscopy within acceptable limits, creating delays in processing samples. In this report, the feasibility of determining the total moisture from TGA-MS measurements at a lower temperature is investigated. A temperature of the TGA-MS analysis which reduces the complications caused by the condensation of volatile materials is determined. Analysis shows that an excellent prediction of the presently measured total moisture value can be made using only the data generated up to 700 °C and there is a sound physical basis for this estimate. It is recommended that the maximum temperature of the TGA-MS determination of total moisture for the 3013 DE program be reduced from 1000 °C to 700 °C. It is also suggested that cumulative moisture measurements at 550 °C and 700°C be substituted for the measured value of total moisture in the 3013 DE database. Using these raw values, any of predictions of the total moisture discussed in this report can be made.

  11. AtTGA4, a bZIP transcription factor, confers drought resistance by enhancing nitrate transport and assimilation in Arabidopsis thaliana.

    PubMed

    Zhong, Li; Chen, Dandan; Min, Donghong; Li, Weiwei; Xu, Zhaoshi; Zhou, Yongbin; Li, Liancheng; Chen, Ming; Ma, Youzhi

    2015-02-13

    To cope with environmental stress caused by global climate change and excessive nitrogen application, it is important to improve water and nitrogen use efficiencies in crop plants. It has been reported that higher nitrogen uptake could alleviate the damaging impact of drought stress. However, there is scant evidence to explain how nitrogen uptake affects drought resistance. In this study we observed that bZIP transcription factor AtTGA4 (TGACG motif-binding factor 4) was induced by both drought and low nitrogen stresses, and that overexpression of AtTGA4 simultaneously improved drought resistance and reduced nitrogen starvation in Arabidopsis. Following drought stress there were higher nitrogen and proline contents in transgenic AtTGA4 plants than in wild type controls, and activity of the key enzyme nitrite reductase (NIR) involved in nitrate assimilation processes was also higher. Expressions of the high-affinity nitrate transporter genes NRT2.1 and NRT2.2 and nitrate reductase genes NIA1 and NIA2 in transgenic plants were all higher than in wild type indicating that higher levels of nitrate transport and assimilation activity contributed to enhanced drought resistance of AtTGA4 transgenic plants. Thus genetic transformation with AtTGA4 may provide a new approach to simultaneously improve crop tolerance to drought and low nitrogen stresses.

  12. Reusable and mediator-free cholesterol biosensor based on cholesterol oxidase immobilized onto TGA-SAM modified smart bio-chips.

    PubMed

    Rahman, Mohammed M

    2014-01-01

    A reusable and mediator-free cholesterol biosensor based on cholesterol oxidase (ChOx) was fabricated based on self-assembled monolayer (SAM) of thioglycolic acid (TGA) (covalent enzyme immobilization by dropping method) using bio-chips. Cholesterol was detected with modified bio-chip (Gold/Thioglycolic-acid/Cholesterol-oxidase i.e., Au/TGA/ChOx) by reliable cyclic voltammetric (CV) technique at room conditions. The Au/TGA/ChOx modified bio-chip sensor demonstrates good linearity (1.0 nM to 1.0 mM; R = 0.9935), low-detection limit (∼0.42 nM, SNR∼3), and higher sensitivity (∼74.3 µA µM(-1) cm(-2)), lowest-small sample volume (50.0 μL), good stability, and reproducibility. To the best of our knowledge, this is the first statement with a very high sensitivity, low-detection limit, and low-sample volumes are required for cholesterol biosensor using Au/TGA/ChOx-chips assembly. The result of this facile approach was investigated for the biomedical applications for real samples at room conditions with significant assembly (Au/TGA/ChOx) towards the development of selected cholesterol biosensors, which can offer analytical access to a large group of enzymes for wide range of biomedical applications in health-care fields.

  13. Concentration-dependent optical properties of TGA stabilized CdTe Quantum dots synthesized via the single injection hydrothermal method in the ambient environment

    NASA Astrophysics Data System (ADS)

    Jai Kumar, B.; Mahesh, H. M.

    2017-04-01

    Thioglycolic acid (TGA) stabilized aqueous CdTe Quantum dots (QDs) were synthesized using a facile, cost efficient Single Injection Hydrothermal (SIH) method. The complete preparation of precursors and growth of QDs was carried out in the ambient environment without inter gas protection. The Cadmium and Tellurium precursors were prepared from cadmium nitrate and elemental tellurium powder with sodium borohydride as reducing agent respectively. A systematic investigation was carried out in order to study the effect of 0.04M and 0.08M TGA concentration on ease synthesis, stability and size-tunable optical absorbance, bandgap, photoluminescence (PL) and Quantum yield (QY) of CdTe QDs. The Structure of QDs was verified by XRD and optical properties by absorbance and PL spectra. Experimental results revealed that the 0.08M TGA QDs possess good chemical and optical stability with high luminescence and decent QY, ready to use in optoelectronics, photovoltaic and biological application.

  14. Employment of electrochemically synthesized TGA-CdSe quantum dots for Cr(3+) determination in vitamin supplements.

    PubMed

    de Souza, Gustavo C S; de Santana, Éden E A; da Silva, Paulo A B; Freitas, Denilson V; Navarro, Marcelo; Paim, Ana Paula S; Lavorante, André F

    2015-11-01

    The fluorescence quenching of TGA-CdSe quantum dots (QDs) was used for Cr(3+) quantification in vitamin supplements. The QD was electrochemically synthesized, demonstrating high reproducibility with control of particle size, thus making it a clean method, without the presence of reducing agents. Under ideal conditions, with the fluorescence band at 551 nm (excitation 365 nm), the maximum fluorescence quenching was observed at pH 4.0, with a time of 200 s for each data acquisition. Under optimum experimental conditions, linear quenching was observed for Cr(3+) in the range of 25.0-325.0 ng L(-1) (R=0.9996, n=6), a limit of detection of 5.67 ng L(-1), and relative standard deviation of 4.43% (n=10). The recovery test for Cr(3+) quantification in vitamin supplements presented results from 82% to 98%. These Cr(3+) determination results were compared to the same vitamin supplement sample using flame atomic absortion spectrometry (FAAS) method, and no significant differences were observed at 95% confidence level.

  15. Photo-induced interaction of thioglycolic acid (TGA)-capped CdTe quantum dots with cyanine dyes.

    PubMed

    Abdelbar, Mostafa F; Fayed, Tarek A; Meaz, Talaat M; Ebeid, El-Zeiny M

    2016-11-05

    The photo-induced interaction of three different sizes of thioglycolic acid (TGA)-capped CdTe quantum dots (CdTe QDs) with two monomethine cyanine dyes belonging to the thiazole orange (TO) family has been studied. Positively charged cyanines interact with QDs surface which is negatively charged due to capping agent carboxylate ions. The energy transfer parameters including Stern-Volmer constant, Ksv, number of binding sites, n, quenching sphere radius, r, the critical energy transfer distance, R0, and energy transfer efficiencies, E have been calculated. The effect of structure and the number of aggregating molecules have been studied as a function of CdTe QDs particle size. Combining organic and inorganic semiconductors leads to increase of the effective absorption cross section of the QDs which can be utilized in novel nanoscale designs for light-emitting, photovoltaic and sensor applications. A synthesized triplet emission of the studied dyes was observed using CdTe QDs as donors and this is expected to play a potential role in molecular oxygen sensitization and in photodynamic therapy (PDT) applications.

  16. Photo-induced interaction of thioglycolic acid (TGA)-capped CdTe quantum dots with cyanine dyes

    NASA Astrophysics Data System (ADS)

    Abdelbar, Mostafa F.; Fayed, Tarek A.; Meaz, Talaat M.; Ebeid, El-Zeiny M.

    2016-11-01

    The photo-induced interaction of three different sizes of thioglycolic acid (TGA)-capped CdTe quantum dots (CdTe QDs) with two monomethine cyanine dyes belonging to the thiazole orange (TO) family has been studied. Positively charged cyanines interact with QDs surface which is negatively charged due to capping agent carboxylate ions. The energy transfer parameters including Stern-Volmer constant, Ksv, number of binding sites, n, quenching sphere radius, r, the critical energy transfer distance, R0, and energy transfer efficiencies, E have been calculated. The effect of structure and the number of aggregating molecules have been studied as a function of CdTe QDs particle size. Combining organic and inorganic semiconductors leads to increase of the effective absorption cross section of the QDs which can be utilized in novel nanoscale designs for light-emitting, photovoltaic and sensor applications. A synthesized triplet emission of the studied dyes was observed using CdTe QDs as donors and this is expected to play a potential role in molecular oxygen sensitization and in photodynamic therapy (PDT) applications.

  17. Murein Lytic Enzyme TgaA of Bifidobacterium bifidum MIMBb75 Modulates Dendritic Cell Maturation through Its Cysteine- and Histidine-Dependent Amidohydrolase/Peptidase (CHAP) Amidase Domain

    PubMed Central

    Zanoni, Ivan; Balzaretti, Silvia; Miriani, Matteo; Taverniti, Valentina; De Noni, Ivano; Presti, Ilaria; Stuknyte, Milda; Scarafoni, Alessio; Arioli, Stefania; Iametti, Stefania; Bonomi, Francesco; Mora, Diego; Karp, Matti; Granucci, Francesca

    2014-01-01

    Bifidobacteria are Gram-positive inhabitants of the human gastrointestinal tract that have evolved close interaction with their host and especially with the host's immune system. The molecular mechanisms underlying such interactions, however, are largely unidentified. In this study, we investigated the immunomodulatory potential of Bifidobacterium bifidum MIMBb75, a bacterium of human intestinal origin commercially used as a probiotic. Particularly, we focused our attention on TgaA, a protein expressed on the outer surface of MIMBb75's cells and homologous to other known bacterial immunoactive proteins. TgaA is a peptidoglycan lytic enzyme containing two active domains: lytic murein transglycosylase (LT) and cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP). We ran immunological experiments stimulating dendritic cells (DCs) with the B. bifidum MIMBb75 and TgaA, with the result that both the bacterium and the protein activated DCs and triggered interleukin-2 (IL-2) production. In addition, we observed that the heterologous expression of TgaA in Bifidobacterium longum transferred to the bacterium the ability to induce IL-2. Subsequently, immunological experiments performed using two purified recombinant proteins corresponding to the single domains LT and CHAP demonstrated that the CHAP domain is the immune-reactive region of TgaA. Finally, we also showed that TgaA-dependent activation of DCs requires the protein CD14, marginally involves TRIF, and is independent of Toll-like receptor 4 (TLR4) and MyD88. In conclusion, our study suggests that the bacterial CHAP domain is a novel microbe-associated molecular pattern actively participating in the cross talk mechanisms between bifidobacteria and the host's immune system. PMID:24814791

  18. Murein lytic enzyme TgaA of Bifidobacterium bifidum MIMBb75 modulates dendritic cell maturation through its cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP) amidase domain.

    PubMed

    Guglielmetti, Simone; Zanoni, Ivan; Balzaretti, Silvia; Miriani, Matteo; Taverniti, Valentina; De Noni, Ivano; Presti, Ilaria; Stuknyte, Milda; Scarafoni, Alessio; Arioli, Stefania; Iametti, Stefania; Bonomi, Francesco; Mora, Diego; Karp, Matti; Granucci, Francesca

    2014-09-01

    Bifidobacteria are Gram-positive inhabitants of the human gastrointestinal tract that have evolved close interaction with their host and especially with the host's immune system. The molecular mechanisms underlying such interactions, however, are largely unidentified. In this study, we investigated the immunomodulatory potential of Bifidobacterium bifidum MIMBb75, a bacterium of human intestinal origin commercially used as a probiotic. Particularly, we focused our attention on TgaA, a protein expressed on the outer surface of MIMBb75's cells and homologous to other known bacterial immunoactive proteins. TgaA is a peptidoglycan lytic enzyme containing two active domains: lytic murein transglycosylase (LT) and cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP). We ran immunological experiments stimulating dendritic cells (DCs) with the B. bifidum MIMBb75 and TgaA, with the result that both the bacterium and the protein activated DCs and triggered interleukin-2 (IL-2) production. In addition, we observed that the heterologous expression of TgaA in Bifidobacterium longum transferred to the bacterium the ability to induce IL-2. Subsequently, immunological experiments performed using two purified recombinant proteins corresponding to the single domains LT and CHAP demonstrated that the CHAP domain is the immune-reactive region of TgaA. Finally, we also showed that TgaA-dependent activation of DCs requires the protein CD14, marginally involves TRIF, and is independent of Toll-like receptor 4 (TLR4) and MyD88. In conclusion, our study suggests that the bacterial CHAP domain is a novel microbe-associated molecular pattern actively participating in the cross talk mechanisms between bifidobacteria and the host's immune system.

  19. Thermal: Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Polarized Microscopy Instrumentation for the Analysis of Field-Controlled Anisotropic Nanomaterials

    DTIC Science & Technology

    2014-11-14

    figure 1.2.1, right). The discovery TGA furnace design employs a silicon carbide ( SiC ) inner chamber. Four halogen lamps surrounded by a water...amplification,(13, 17) self-phase modulation (18, 19), and new nonlinear phenomena such as the nonlinear optical mirror ,(20) and the mirrorless optical

  20. TgaA, a VirB1-Like Component Belonging to a Putative Type IV Secretion System of Bifidobacterium bifidum MIMBb75

    PubMed Central

    Balzaretti, Silvia; Taverniti, Valentina; Miriani, Matteo; Milani, Christian; Scarafoni, Alessio; Corona, Silvia; Ciranna, Alessandro; Arioli, Stefania; Santala, Ville; Iametti, Stefania; Bonomi, Francesco; Ventura, Marco; Mora, Diego; Karp, Matti

    2014-01-01

    Bifidobacterium bifidum MIMBb75 is a human intestinal isolate demonstrated to be interactive with the host and efficacious as a probiotic. However, the molecular biology of this microorganism is yet largely unknown. For this reason, we undertook whole-genome sequencing of B. bifidum MIMBb75 to identify potential genetic factors that would explain the metabolic and probiotic attributes of this bacterium. Comparative genomic analysis revealed a 45-kb chromosomal region that comprises 19 putative genes coding for a potential type IV secretion system (T4SS). Thus, we undertook the initial characterization of this genetic region by studying the putative virB1-like gene, named tgaA. Gene tgaA encodes a peptidoglycan lytic enzyme containing two active domains: lytic murein transglycosylase (LT, cd00254.3) and cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP, pfam05257.4). By means of several in vitro assays, we experimentally confirmed that protein TgaA, consistent with its computationally assigned role, has peptidoglycan lytic activity, which is principally associated to the LT domain. Furthermore, immunofluorescence and immunogold labeling showed that the protein TgaA is abundantly expressed on the cell surface of B. bifidum MIMBb75. According to the literature, the T4SSs, which have not been characterized before in bifidobacteria, can have important implications for bacterial cell-to-cell communication as well as cross talk with host cells, justifying the interest for further studies aimed at the investigation of this genetic region. PMID:24951779

  1. TgaA, a VirB1-like component belonging to a putative type IV secretion system of Bifidobacterium bifidum MIMBb75.

    PubMed

    Guglielmetti, Simone; Balzaretti, Silvia; Taverniti, Valentina; Miriani, Matteo; Milani, Christian; Scarafoni, Alessio; Corona, Silvia; Ciranna, Alessandro; Arioli, Stefania; Santala, Ville; Iametti, Stefania; Bonomi, Francesco; Ventura, Marco; Mora, Diego; Karp, Matti

    2014-09-01

    Bifidobacterium bifidum MIMBb75 is a human intestinal isolate demonstrated to be interactive with the host and efficacious as a probiotic. However, the molecular biology of this microorganism is yet largely unknown. For this reason, we undertook whole-genome sequencing of B. bifidum MIMBb75 to identify potential genetic factors that would explain the metabolic and probiotic attributes of this bacterium. Comparative genomic analysis revealed a 45-kb chromosomal region that comprises 19 putative genes coding for a potential type IV secretion system (T4SS). Thus, we undertook the initial characterization of this genetic region by studying the putative virB1-like gene, named tgaA. Gene tgaA encodes a peptidoglycan lytic enzyme containing two active domains: lytic murein transglycosylase (LT, cd00254.3) and cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP, pfam05257.4). By means of several in vitro assays, we experimentally confirmed that protein TgaA, consistent with its computationally assigned role, has peptidoglycan lytic activity, which is principally associated to the LT domain. Furthermore, immunofluorescence and immunogold labeling showed that the protein TgaA is abundantly expressed on the cell surface of B. bifidum MIMBb75. According to the literature, the T4SSs, which have not been characterized before in bifidobacteria, can have important implications for bacterial cell-to-cell communication as well as cross talk with host cells, justifying the interest for further studies aimed at the investigation of this genetic region.

  2. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    SciTech Connect

    Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.; Kruger, Albert A.; Chun, Jaehun; Hrma, Pavel R.

    2013-12-03

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.

  3. Pyrolysis of oil-plant wastes in a TGA and a fixed-bed reactor: Thermochemical behaviors, kinetics, and products characterization.

    PubMed

    Chen, Jianbiao; Fan, Xiaotian; Jiang, Bo; Mu, Lin; Yao, Pikai; Yin, Hongchao; Song, Xigeng

    2015-09-01

    Pyrolysis characteristics of four distinct oil-plant wastes were investigated using TGA and fixed-bed reactor coupled with GC. TGA experiments showed that the pyrolysis behaviors were related to biomass species and heating rates. As the heating rate increased, TG and DTG curves shifted to the higher temperatures, and the comprehensive devolatilization index obviously increased. The remaining chars from TGA experiments were higher than those obtained from the fixed-bed experiments. The crack of tars at high temperatures enhanced the formation of non-condensable gases. During the pyrolysis, C-O and CO2 were the major gases. Chars FTIR showed that the functional groups of O-H, C-H(n), C=O, C-O, and C-C gradually disappeared from 400 °C on. The kinetic parameters were calculated by Coats-Redfern approach. The results manifested that the most appropriate pyrolysis mechanisms were the order reaction models. The existence of kinetic compensation effect was evident.

  4. Raman spectroscopy and TGA studies for the synthesis of multi-walled carbon nanotube-functionalized thiol (MWCNT-SH) nanocomposites: study of effect of concentration

    NASA Astrophysics Data System (ADS)

    Robati, D.; Bagheriyan, S.; Rajabi, M.

    2015-05-01

    We have investigated some methods such as Raman spectroscopy and thermogravimetric analysis (TGA) studies for the nanocomposites multi-walled carbon nanotube-functionalized thiol (MWCNT-SH) by adding to cysteamine with known concentration in nanocomposite. For this study, we synthesized nanocomposite MWCNT-SH by the reaction between multi-walled carbon nanotubes-functionalized carboxyl and the cysteamine. For study of the effect of concentration, cysteamine with different concentrations was used (1, 3 and 5 % weight) and it was called MWCNT-SH1, MWCNT-SH3 and MWCNT-SH5, respectively. Then, the nanocomposite provided was characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The surface structure of nanocomposites can be analyzed and confirmed using Raman and FT-IR spectroscopy. Also, to investigate the thermal stability TGA was used. The study of TGA showed that nanocomposite MWCNT-SH had low thermal stability at temperatures more than 100 °C.

  5. An experimental study of the (Ti-6Al-4V)-xH phase diagram using in situ synchrotron XRD and TGA/DSC techniques.

    SciTech Connect

    Sun, Pei; Fang, Z. Zak; Koopman, Mark; Paramore, James D.; Chandran, K. S. Ravi; Ren, Yang; Lu, Jun

    2015-02-01

    Hydrogen has been investigated for decades as a temporary alloying element to refine the microstructure of Ti-6Al-4V, and is now being used in a novel powder metallurgy method known as "hydrogen sintering and phase transformation". Pseudo-binary phase diagrams of (Ti-6Al-4V)-xH have been studied and developed, but are not well established due to methodological limitations. In this paper, in situ studies of phase transformations during hydrogenation and dehydrogenation of (Ti-6Al-4V)-xH alloys were conducted using high-energy synchrotron X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The eutectoid phase transformation of β ↔ α + δ was observed in the (Ti-6Al-4V)-xH alloy via in situ synchrotron XRD at 211 °C with a hydrogen concentration of 37.5 at.% (measured using TGA-DSC). The relationships of hydrogen composition to partial pressure and temperature were investigated in the temperature range 450-900°C. Based on these results, a partial pseudo-binary phase diagram of (Ti-6Al-4V)-xH is proposed for hydrogen compositions up to 60 at.% in the temperature range 100-900°C. Using the data collected in real time under controlled parameters of temperature, composition and hydrogen partial pressure, this work characterizes relevant phase transformations and microstructural evolution for practical titanium-hydrogen technologies of Ti-6Al-4V.

  6. Catalytic pyrolysis of wheat bran for hydrocarbons production in the presence of zeolites and noble-metals by using TGA-FTIR method.

    PubMed

    Lazdovica, K; Liepina, L; Kampars, V

    2016-05-01

    Pyrolysis of wheat bran with or without catalysts was investigated using TGA-FTIR method in order to determine the influence of zeolite and noble metal catalysts on the evolution profile and relative yield of the volatile compounds. The addition of all catalysts decreased the volatile matter of wheat bran from 76.3% to 75.9%, 73.9%, 73.5%, 69.7% and increased the solid residue from 18.0% to 18.4%, 20.4%, 20.8%, 24.6% under the catalyst of ZSM-5, 5% Pd/C, MCM-41, and 5% Pt/C. Noble-metal catalysts had higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than zeolites. Degradation of nitrogen containing compounds atom proceeded better in presence of zeolites. Noble-metal catalysts promoted formation of aromatics and changed the profiles of evolved compounds whereas zeolites advanced formation of aliphatics and olefins.

  7. Effects of water washing and torrefaction on the pyrolysis behavior and kinetics of rice husk through TGA and Py-GC/MS.

    PubMed

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan

    2016-01-01

    The effects of water washing and torrefaction on the pyrolysis behavior and kinetics of rice husk were investigated through TGA and Py-GC/MS in this study. Two iso-conversional methods, i.e. Starink and FWO methods were applied for determination of the activation energy of original and pretreated rice husk samples at three different heating rates. It was found that activation energy of water washed rice husk was lower than that of original rice husk. Whereas, the activation energy increased with the increase of torrefaction temperature. The result of Py-GC/MS analysis indicated that both water washing and torrefaction pretreatments decreased the contents of acids, ketones, aldehydes and furans, while significantly increased the contents of sugars, especially levoglucosan. The relative content of released levoglucosan from pyrolysis of rice husk sample with combined water washing and 280°C torrefaction pretreatment is almost 9 times of that from original rice husk, which is about 3%.

  8. Solid-state MAS NMR, TEM, and TGA studies of structural hydroxyl groups and water in nanocrystalline apatites prepared by dry milling.

    PubMed

    Pajchel, Lukasz; Kolodziejski, Waclaw

    2013-01-01

    A series of nanocrystalline calcium hydroxyapatites was prepared by dry milling and characterized using proton and (31)P MAS NMR, TEM, and TGA methods. The samples contained stubby rod-shaped crystals, which length and width varied in the 130-30 and 95-20 nm ranges, respectively. It was confirmed that concentration of structural hydroxyl groups in nanocrystalline apatites decreases with the decreasing crystal size. In the series of the studied apatites, the decrease was from 86 to ca. 50 % in reference to stoichiometric apatite. Water was found in the surface hydrated layer and in the c-axis channels, in which compartments existed as adsorbed and structural, respectively. Molecules of the adsorbed water were capable of moving from the crystal surface into the lattice c-axis channels of apatite. This process introduced considerable structural disorder within and around those channels and reduced the content of the structural hydroxyl groups, particularly in the region underneath the apatite crystal surface.

  9. Glycine reductase of Clostridium litorale. Cloning, sequencing, and molecular analysis of the grdAB operon that contains two in-frame TGA codons for selenium incorporation.

    PubMed

    Kreimer, S; Andreesen, J R

    1995-11-15

    A 2.8-kb HindIII fragment, containing three open reading frames, has been cloned and sequenced from Clostridium litorale. The first gene grdA encoded the selenocysteine-containing protein PA of the glycine reductase complex, a protein of 159 amino acids with a deduced molecular mass of 16.7 kDa. The second gene (grdB) encoded the 47-kDa subunit of the substrate-specific selenoprotein PB glycine that is composed of 437 amino acids. The third gene contained the 5'-region of the gene for thioredoxin reductase, trxB. All gene products shared high similarity with the corresponding proteins from Eubacterium acidaminophilum. In both genes grdA and grdB, the opal termination codon (TGA) was found inframe, indicating the presence of selenocysteine in both polypeptides. Northern-blot analysis showed that grdA and grdB are organized as one operon. Unlike Escherichia coli, no stable secondary structures of the corresponding mRNA were found immediately downstream of the UGA codons to direct an insertion of selenocysteine into the grdA and grdB transcripts of C. litorale. Instead, a secondary structure was identified in the 3'-untranslated region of grdB.

  10. Alteration of skin hydration and its barrier function by vehicle and permeation enhancers: a study using TGA, FTIR, TEWL and drug permeation as markers.

    PubMed

    Shah, D K; Khandavilli, S; Panchagnula, R

    2008-09-01

    Vehicles and permeation enhancers (PEs) used in transdermal drug delivery (TDD) of a drug can affect skin hydration, integrity and permeation of the solute administered. This investigation was designed to study the effect of the most commonly used vehicles and PEs on rat skin hydration, barrier function and permeation of an amphiphilic drug, imipramine hydrochloride (IMH). An array of well-established techniques were used to confirm the findings of the study. Thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy were used to determine changes in skin hydration. Alteration of the stratum corneum (SC) structure was investigated using FTIR studies. To monitor the barrier function alteration, transepidermal water loss (TEWL) measurement and permeation studies were performed. Our findings indicate that with hydration, there was an increase in the bound water content of the skin, and pseudoequilibrium of hydration (a drastic decrease in hydration rate) was achieved at around 12 h. Hydration increased the ratio between amide-I and amide-II peaks in FTIR and reduced the C-H stretching peak area. Both propylene glycol (PG) and ethanol (EtOH) dehydrated skin, with the latter showing a predominant effect. Furthermore, it was confirmed that PG and EtOH decreased the bound water content due to alteration in the protein domains and extraction of SC lipids, respectively. The effect of hydration on the SC was found to be similar to that reported for temperature. Permeation studies revealed that the dehydration caused by vehicles decreased IMH flux, whereas the flux was enhanced by PEs. The role of partition was predominant for the permeation of IMH through dehydrated skin. A synergistic effect was observed for PG and menthol in the enhancement of IMH. Further findings provided strong evidence that PG affects protein domains and EtOH extracts lipids from the bilayer. Both PG and EtOH, with or without PEs, increased TEWL. Initial TEWL was well

  11. Four-dimensional visualization of thoracic blood flow by magnetic resonance imaging in a patient following correction of transposition of the great arteries (d-TGA) and uncorrected aortic coarctation.

    PubMed

    Ley-Zaporozhan, J; Unterhinninghofen, R; Rengier, F; Markl, M; Eichhorn, J; von Tengg-Kobligk, H; Ley, S

    2009-10-01

    Recent advances in flow-sensitive magnetic resonance imaging (MRI) and data analysis allow for comprehensive noninvasive three-dimensional (3D) visualization of complex blood flow. Electrocardiogram (ECG)-gated three-directional (3dir) flow measurements were employed to assess and visualize time-resolved 3D blood flow in the pulmonary arteries (PA) and thoracic aorta. We present findings in a juvenile patient with surgically corrected transposition of the great arteries (d-TGA) and aortic coarctation. For the first time, the complex flow patterns in the PA following d-TGA were visualized. Morphologically, a slight asymmetry of the PA was found, with considerable impact on vascular hemodynamics, resulting in diastolic retrograde flow in the larger vessel and diastolic filling of the smaller PA. Additionally, increased flow to the supraaortic vessels was found due to aortic coarctation.

  12. A Comparison of combustion of coal chars in O{sub 2}/CO{sub 2} and O{sub 2}/N{sub 2} mixtures - isothermal TGA studies - article no. A74

    SciTech Connect

    Liu, H.

    2009-07-01

    Two chars prepared from parent coals of a high volatile bituminous coal and an anthracite coal were subjected to isothermal combustion tests in a thermogravimetric analyser (TGA). The chars were burned in mixtures of O{sub 2}/CO{sub 2} and O{sub 2}/N{sub 2} with O{sub 2} concentrations of 3%, 6%, 10%, 21% and 30% and combustion temperature ranging from 723 K to 1163 K. Experimental results show that replacing the inert nitrogen gas in the oxidizer with CO{sub 2} has little influence on the measured reactivity of coal chars under conditions of the experiments. The measured reactivity of each char was found to be approximately first order (0.88 - 0.90) to the concentration of O{sub 2} in the O{sub 2}/CO{sub 2} mixtures. As char combustion tests were conducted under relatively high temperatures conditions, internal and external effectiveness factors were estimated in order to derive combustion kinetics of both chars. The values of activation energy for both chars, obtained by taking account of both the internal and external effectiveness factors (i.e. with correction), were very much in line with the literature data. The activation energy of the bituminous coal char combustion in O{sub 2}/CO{sub 2} was found to be 96323 (without correction) - 108893 (with correction) kJ/kmol within the temperature range of 723 - 873 K, whereas the activation energy of the anthracite char was found to be 125716 (without correction) - 140486 (with correction) kJ/kmol within the temperature range of 773 - 973 K.

  13. Arabidopsis genes, AtNPR1, AtTGA2 and AtPR-5, confer partial resistance to soybean cyst nematode (Heterodera glycines) when overexpressed in transgenic soybean roots

    PubMed Central

    2014-01-01

    Background Extensive studies using the model system Arabidopsis thaliana to elucidate plant defense signaling and pathway networks indicate that salicylic acid (SA) is the key hormone triggering the plant defense response against biotrophic and hemi-biotrophic pathogens, while jasmonic acid (JA) and derivatives are critical to the defense response against necrotrophic pathogens. Several reports demonstrate that SA limits nematode reproduction. Results Here we translate knowledge gained from studies using Arabidopsis to soybean. The ability of thirty-one Arabidopsis genes encoding important components of SA and JA synthesis and signaling in conferring resistance to soybean cyst nematode (SCN: Heterodera glycines) are investigated. We demonstrate that overexpression of three of thirty-one Arabidoposis genes in transgenic soybean roots of composite plants decreased the number of cysts formed by SCN to less than 50% of those found on control roots, namely AtNPR1(33%), AtTGA2 (38%), and AtPR-5 (38%). Three additional Arabidopsis genes decreased the number of SCN cysts by 40% or more: AtACBP3 (53% of the control value), AtACD2 (55%), and AtCM-3 (57%). Other genes having less or no effect included AtEDS5 (77%), AtNDR1 (82%), AtEDS1 (107%), and AtPR-1 (80%), as compared to control. Overexpression of AtDND1 greatly increased susceptibility as indicated by a large increase in the number of SCN cysts (175% of control). Conclusions Knowledge of the pathogen defense system gained from studies of the model system, Arabidopsis, can be directly translated to soybean through direct overexpression of Arabidopsis genes. When the genes, AtNPR1, AtGA2, and AtPR-5, encoding specific components involved in SA regulation, synthesis, and signaling, are overexpressed in soybean roots, resistance to SCN is enhanced. This demonstrates functional compatibility of some Arabidopsis genes with soybean and identifies genes that may be used to engineer resistance to nematodes. PMID:24739302

  14. Technique of Coronary Transfer for TGA with Single Coronary Artery

    PubMed Central

    Kim, Tae Ho; Jung, Jae Jun; Kim, Yong Han; Yang, Ji-Hyuk; Jun, Tae-Gook

    2014-01-01

    An eight-day-old neonate was diagnosed with dextro-transposition of the great arteries, atrial septal defect, patent ductus arteriosus, and a single sinus origin of the coronary arteries. The single coronary artery originated from the left sinus (sinus 2), had a proximal left circumflex arterial branch, and passed anteriorly to the right side of the aorta, further branching into the right coronary and left anterior descending arteries. We successfully performed an arterial switch operation and coronary transfer by tube graft reconstruction with autologous aortic tissue to treat the dextro-transposition of the great arteries and atrial septal defect with a single-sinus origin of the coronary arteries. PMID:25551074

  15. [Ni(OH)3W6O18(OCH2)3CCH2OH]4–: the first tris-functionalized Anderson-type heteropolytungstate† †Electronic supplementary information (ESI) available: Experimental procedures, synthesis details, characterization data, including IR, ESI-MS, TGA, elemental analysis and X-ray crystallography with CIF file. CCDC 1477611. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6cc04326g Click here for additional data file. Click here for additional data file.

    PubMed Central

    Gumerova, Nadiia I.; Roller, Alexander

    2016-01-01

    Na2[TMA]2[Ni(OH)3W6O18(OCH2)3CCH2OH]·9H2O represents the first covalent tris-functionalized Anderson-type heteropolytungstate and was characterized by single-crystal X-ray diffraction, electrospray ionization mass spectrometry, TGA and IR spectroscopy. Zeta potential measurements in solutions containing human serum albumin were performed to investigate electrostatic interactions with [Ni(OH)3W6O18(OCH2)3CCH2OH]4–. PMID:27355393

  16. Influence of biomass blending on pyrolysis process using TGA-FTIR technique

    NASA Astrophysics Data System (ADS)

    Bibrzycki, Jakub; Katelbach-Woźniak, Anna; Szlek, Andrzej

    2014-08-01

    Devolatilization is the most important step in the biomass combustion. It is beneficial to use a fuel, which releases volatiles in a wider range of temperature that make easier proper air distribution. The main objective of this paper is influence investigation of biomass mixing on devolatilization process. Thermobalance coupled with FTIR spectrometer has been used for investigation of devolatilization process and analysis of released gases composition. For the experiments inert atmosphere, sample mass of 50 mg and heating rate of 10 K/min have been used. As investigated fuels, the most popular types of biomass such as pine, willow and wheat straw have been used. Results show that by mixing different types of biomasses one can influence maximal rate of pyrolysis (DTGmax), corresponding temperature and composition of released volatiles. Results prove existence of interactions between different sorts of biomass.

  17. Novel use of TGA-FTIR technique to predict the pollution degree in marine sediments

    NASA Astrophysics Data System (ADS)

    Oudghiri, Fatiha; García-Morales, José Luis; Rodríguez-Barroso, María Rocío

    2015-09-01

    In this work, thermogravimetric analysis (TG) coupled with Fourier transform infrared spectrometry (TG-FTIR) was applied to compare the thermal behavior of sediments from Cadiz port and a pristine zone. The samples were thermally degraded in air atmosphere using a heating rate of 10 °C/min. The Physico-Chemical analyses (organic matter, organic carbon, carbonate, total nitrogen, moisture, granulometric analyses; Cu, Zn, Pb and Hg) of sediments indicate that the pollution in zone coming from Cadiz port is mainly of anthropogenic origin. By means of differential thermogravimetric (DTG) and Gram-Schmidt the curves of sediments coming from Cadiz port, showed four stages with temperatures of maximum decomposition rate approximately at 120 °C, 292 °C, 493 °C and 741 °C. The FTIR spectra corresponding to these temperatures shows the formation of high quantities of gases, as carbon dioxide, carbon monoxide, water vapor, aliphatic hydrocarbons, ether and ammonia, while in sediment coming from pristine zone the thermal degradation occurs in two stages, with temperatures of maximum decomposition rate around 500 °C and 750 °C, producing only little quantities of gases, as carbon dioxide and water vapor. By comparing the TG-FTIR of sediments coming from the port and the no polluted zone, it is possible to identify the volatile organic compounds emitted between 200 and 600 °C. These results suggest that modifications in the structures of sediment from the port are due to different sources of contamination. This study demonstrates that TG-FTIR is capable for screening of contaminated sediments.

  18. Synthesis, fluorescence, TGA and crystal structure of thiazolyl-pyrazolines derived from chalcones

    NASA Astrophysics Data System (ADS)

    Suwunwong, T.; Chantrapromma, S.; Fun, H.-K.

    2015-04-01

    Thiazolyl-pyrazolines 3a-3d were synthesized in a three step procedure using chalcones as starting materials and characterized by FT-IR, UV-Vis, and 1H NMR techniques. The crystal structure of compound 3a was also determined by X-ray diffraction analysis. Compound 3a crystallized out in the orthorhombic P212121 space group with the unit cell dimensions: a = 5.2106(2) Å, b = 12.4341(5) Å, c = 33.3254(13) Å, α = β = γ = 90°, V = 2159.12(15) Å3, Z = 4, D cald = 1.372 M gm-3 and F(000) = 928. Fluorescence of 3a-3d were studied in solid state and acetonitrile solution. It was found that, these compounds exhibit the green fluorescence light (506-508 nm) in both solid and solution states. The pH stability on fluorescence property and the thermal gravimetric analysis of compound 3a were specifically carried out. It was revealed that 3a shows high thermal stability up to around 250°C and presenting high stability in various pH ranges in the acetonitrilewater matrix.

  19. Thermal properties of tannin extracted from Anacardium occidentale L. using TGA and FT-IR spectroscopy.

    PubMed

    Viswanath, Vinod; Leo, Vincent Vineeth; Prabha, S Sabna; Prabhakumari, C; Potty, V P; Jisha, M S

    2016-01-01

    The chemical nature of the polyphenols of cashew kernel testa has been determined. Testa contains tannins, which present large molecular complexity and has an ancient use as tanning agents. The use of tannins extracted from cashew testa, considered in many places as a waste, grants an extra value to the cashew. In this work we have analysed through high performance liquid chromatography, infrared spectroscopy (FT-IR) and thermo gravimetric analysis the average molecular weight, main functional groups and thermal properties of tannins extracted from Anacardium occidentale L. The results of these analyses are compared with the commercial grade tannic acid. The FT-IR spectra showed bands characteristic of C = C, C-C and OH bonds. This important bioactive compound present in the cashew nut kernel testa was suggested as an interesting economical source of antioxidants for use in the food and nutraceutical industry.

  20. Thermal Properties of Extruded Injection-Molded Polycaprolactone/Gluten Bioblends Characterized by TGA, DSC, SEM and Infrared Photoacoustic Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to determine the degree of compatibility between Polycaprolactone resin (PCL) and vital wheat gluten (VG), PCL was compounded with VG at 90:10, 80:20, 70:30, 60:40, 50:50, and 30:70. The composites were blended by extrusion followed by injection molding. Thermal, morphological, and struct...

  1. Combined TGA-MS kinetic analysis of multistep processes. Thermal decomposition and ceramification of polysilazane and polysiloxane preceramic polymers.

    PubMed

    García-Garrido, C; Sánchez-Jiménez, P E; Pérez-Maqueda, L A; Perejón, A; Criado, José M

    2016-10-26

    The polymer-to-ceramic transformation kinetics of two widely employed ceramic precursors, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (TTCS) and polyureamethylvinylsilazane (CERASET), have been investigated using coupled thermogravimetry and mass spectrometry (TG-MS), Raman, XRD and FTIR. The thermally induced decomposition of the pre-ceramic polymer is the critical step in the synthesis of polymer derived ceramics (PDCs) and accurate kinetic modeling is key to attaining a complete understanding of the underlying process and to attempt any behavior predictions. However, obtaining a precise kinetic description of processes of such complexity, consisting of several largely overlapping physico-chemical processes comprising the cleavage of the starting polymeric network and the release of organic moieties, is extremely difficult. Here, by using the evolved gases detected by MS as a guide it has been possible to determine the number of steps that compose the overall process, which was subsequently resolved using a semiempirical deconvolution method based on the Frasier-Suzuki function. Such a function is more appropriate that the more usual Gaussian or Lorentzian functions since it takes into account the intrinsic asymmetry of kinetic curves. Then, the kinetic parameters of each constituent step were independently determined using both model-free and model-fitting procedures, and it was found that the processes obey mostly diffusion models which can be attributed to the diffusion of the released gases through the solid matrix. The validity of the obtained kinetic parameters was tested not only by the successful reconstruction of the original experimental curves, but also by predicting the kinetic curves of the overall processes yielded by different thermal schedules and by a mixed TTCS-CERASET precursor.

  2. IR, 1H NMR, mass, XRD and TGA/DTA investigations on the ciprofloxacin/iodine charge-transfer complex

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Hawary, W. F.; Moussa, Mohamed A. A.

    2011-05-01

    The charge-transfer complex (CTC) of ciprofloxacin drug (CIP) as a donor with iodine (I 2) as a sigma acceptor has been studied spectrophotometrically in CHCl 3. At maximum absorption bands, the stoichiometry of CIP:iodine system was found to be 1:1 ratio according to molar ratio method. The essential spectroscopic data like formation constant ( KCT), molar extinction coefficient ( ɛCT), standard free energy (Δ G°), oscillator strength ( f), transition dipole moment ( μ), resonance energy ( RN) and ionization potential ( ID) were estimated. The spectroscopic techniques such as IR, 1H NMR, mass and UV-vis spectra and elemental analyses (CHN) as well as TG-DTG and DTA investigations were used to characterize the chelating behavior of CIP/iodine charge-transfer complex. The iodine CT interaction was associated with a presence of intermolecular hydrogen bond. The X-ray investigation was carried out to investigate the iodine doping in the synthetic CT complex.

  3. Thermal Analysis System (DSC, TGA, TMA) for Oxidation and Phase Transformation Studies of Alloys with Mestable Phase

    DTIC Science & Technology

    1988-06-01

    Hf on Inconel 718 for Improved High Temperature Oxidation Resistance," High Temp. Technology Vol. 5, No. 3, pp. 131-136, August, 1987. 2. S. Sircar, C...and (b)). (c) The shift in the Nb-Ti (Nb rich end) phase diagram is being determined now via DTA techniques. (Fig. 2). (d) The y’ dissolution

  4. Assessment of Sediment Heavy Metals Pollution Using Screening Methods (XRF, TGA/MS, XRPD and Earthworms Bioassay)

    NASA Astrophysics Data System (ADS)

    Findoráková, Lenka; Šestinová, Ol'ga; Hančul'ák, Jozef; Fedorová, Erika; Zorkovská, Anna

    2016-10-01

    The aim of this study is focused on the use of screening methods (TG/DTA coupled with MS, XRF, AAS, XRPD and earthworm bioassay) for sediments pollution assessing by heavy metals (Cu, Zn, Pb, Hg) coming from the former mining workloads in the central Spis, Eastern Slovakia. The screening methods (XRF, AAS) indicated pollution of studied sediments by Cu, Zn, Pb, Hg. The earthworms Dendrobaena veneta caused in some studied samples decrease of heavy metals concentration after their 7 days’ exposure in sediments. The other screening methods such as thermal analysis and XRPD analysis, does not confirm the specifically changes in physicochemical properties comparing the properties before and after 7 days’ earthworm's exposure.

  5. A Study of the Oxidation Behaviour of Pile Grade A (PGA) Nuclear Graphite Using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and X-Ray Tomography (XRT).

    PubMed

    Payne, Liam; Heard, Peter J; Scott, Thomas B

    2015-01-01

    Pile grade A (PGA) graphite was used as a material for moderating and reflecting neutrons in the UK's first generation Magnox nuclear power reactors. As all but one of these reactors are now shut down there is a need to understand the residual state of the material prior to decommissioning of the cores, in particular the location and concentration of key radio-contaminants such as 14C. The oxidation behaviour of unirradiated PGA graphite was studied, in the temperature range 600-1050°C, in air and nitrogen using thermogravimetric analysis, scanning electron microscopy and X-ray tomography to investigate the possibility of using thermal degradation techniques to examine 14C distribution within irradiated material. The thermal decomposition of PGA graphite was observed to follow the three oxidation regimes historically identified by previous workers with limited, uniform oxidation at temperatures below 600°C and substantial, external oxidation at higher temperatures. This work demonstrates that the different oxidation regimes of PGA graphite could be developed into a methodology to characterise the distribution and concentration of 14C in irradiated graphite by thermal treatment.

  6. Analysis of Two Methods for Characterization of Flame Resistant Military Fabrics and Commercial Textile Fibers: Simultaneous DSC-TGA and Pyrolysis GCMS

    DTIC Science & Technology

    2014-04-04

    military clothing and shelters. Thus, higher demands are put on the industry to improve the flame-resistant ( FR ) properties of high performance...experimental measurements to real-world military situations for protective clothing and fabric shelters. Part of the Army’s effort to support FR ...and textiles to support the transition of new FR polymers under development for clothing and individual equipment. Over several decades, many test

  7. A Study of the Oxidation Behaviour of Pile Grade A (PGA) Nuclear Graphite Using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and X-Ray Tomography (XRT)

    PubMed Central

    Payne, Liam; Heard, Peter J.; Scott, Thomas B.

    2015-01-01

    Pile grade A (PGA) graphite was used as a material for moderating and reflecting neutrons in the UK’s first generation Magnox nuclear power reactors. As all but one of these reactors are now shut down there is a need to understand the residual state of the material prior to decommissioning of the cores, in particular the location and concentration of key radio-contaminants such as 14C. The oxidation behaviour of unirradiated PGA graphite was studied, in the temperature range 600–1050°C, in air and nitrogen using thermogravimetric analysis, scanning electron microscopy and X-ray tomography to investigate the possibility of using thermal degradation techniques to examine 14C distribution within irradiated material. The thermal decomposition of PGA graphite was observed to follow the three oxidation regimes historically identified by previous workers with limited, uniform oxidation at temperatures below 600°C and substantial, external oxidation at higher temperatures. This work demonstrates that the different oxidation regimes of PGA graphite could be developed into a methodology to characterise the distribution and concentration of 14C in irradiated graphite by thermal treatment. PMID:26575374

  8. Turbine generator evaluation for the Eesti-Energia Estonia and Baltic power plants. Export trade information

    SciTech Connect

    1995-12-01

    The report evaluates the feasibility of 200 MW turbines and generators modernization in two Estonian power plants in order to improve performance and/or availability. This is Volume 1 and it includes the following: (1) scope; (2) evaluation approach; (3) summary of major recommendations; (4) performance tests descriptions; (5) current technology -- component description; (6) recommended studies; (7) recommendations; (8) district heating; (9) description of turbine K-200-130; (10) turbine evaluation results; (11) generator; (12) estimation of modernization costs.

  9. Mechanochemical and solvent-free assembly of zirconium-based metal–organic frameworks† †Electronic supplementary information (ESI) available: Selected PXRD, FTIR-ATR, BET, TGA, SEM and DLS data. See DOI: 10.1039/c5cc08972g Click here for additional data file.

    PubMed Central

    Užarević, Krunoslav; Wang, Timothy C.; Moon, Su-Young; Fidelli, Athena M.; Hupp, Joseph T.

    2016-01-01

    We develop the first mechanochemical and solvent-free routes for zirconium metal–organic frameworks, making the frameworks UiO-66 and UiO-66-NH2 accessible on the gram scale without strong acids, high temperatures or excess reactants. The frameworks form either by milling, or spontaneous self-assembly by simply exposing solid mixtures of reactants to organic vapour. The generated frameworks exhibit high porosity and catalytic activity in the hydrolysis of model nerve agents, on par with their solvothermally generated counterparts. PMID:26696097

  10. Characterizing Environmental Transformation of Multi-walled Carbon Nanotubes and Carbon Nano-Fiber Composites using Thermal Analysis and Related Hyphenated Techniques

    EPA Science Inventory

    Thermogravimetric analysis (TGA) coupled with gas chromatography and mass spectroscopy (TGA/GCMS), for the evolved gas analysis, has given insight to the stability and kinetics of structural changes and determining adsorbed organics to nanomaterials and nanocomposites. TGA is als...

  11. A New Coating Process for Production of Coated Magnesium Powders

    DTIC Science & Technology

    2008-04-16

    TGA data for magnesium hydroxide content. TGA analysis of the as-coated powders is a reproducible and accurate method for the determination of... TGA analysis of the as-coated powder, there is approximately 3wt% magnesium hydroxide present in the material due to the process variation compared...11: Magnesium hydroxide content as measured by TGA analysis for the 1-lb batches of as-coated ground powder Figure 12: Nitrometer analysis of

  12. A Study of Hydrogen Adsorption in Pretreated Nanocarbon

    DTIC Science & Technology

    2003-01-01

    and in air atmosphere at 623K for 15min using a box furnace. Prior to the thermal treatment, TGA analysis of Ni-C nanoparticles was carried out to...thermal treatment, TGA analysis of Ni-C nanoparticles was carried out in air and CO2. Figure 1 shows the TGA results of Ni-C nanoparticles. When air was

  13. Transient Global Amnesia and Brain Tumour: Chance Concurrence or Aetiological Association? Case Report and Systematic Literature Review

    PubMed Central

    Milburn-McNulty, Phil; Larner, Andrew J.

    2015-01-01

    We report a patient presenting with episodes of transient amnesia, some with features suggestive of transient global amnesia (TGA), and some more reminiscent of transient epileptic amnesia. Investigation with neuroimaging revealed an intrinsic lesion in the right amygdala, with features suggestive of low-grade neoplasia. We undertook a systematic review of the literature on TGA and brain tumour. Fewer than 20 cases were identified, some of which did not conform to the clinical diagnostic criteria for TGA. Hence, the concurrence of brain tumour and TGA is very rare and of doubtful aetiological relevance. In some brain tumour-associated cases, epilepsy may be masquerading as TGA. PMID:25802501

  14. Biomechanical and biologic effects of meniscus stabilization using triglycidyl amine.

    PubMed

    Hunter, Shawn A; Rapoport, H Scott; Connolly, Jeanne M; Alferiev, Ivan; Fulmer, James; Murti, Brandon H; Herfat, Mohammadsafa; Noyes, Frank R; Butler, David L; Levy, Robert J

    2010-04-01

    The susceptibility of meniscus allografts to enzymatic degradation may be reduced through tissue stabilization. We have previously reported on an epoxide-based crosslinker, triglycidyl amine (TGA), which can be used alone or with a bisphosphonate (MABP) to stabilize heterograft heart valves and reduce their pathologic calcification. Our objective was to evaluate the effects of TGA and TGA-MABP pretreatment on an orthopedic allograft involving meniscus crosslinking, degradation, calcification, and compressive properties. Ovine menisci treated with TGA or TGA-MABP for up to seven days and glutaraldehyde crosslinked controls were examined in vitro for degree of crosslinking, resistance to degradation by collagenase, and material property changes. Likewise treated menisci were implanted in rats for eight weeks and examined for calcium content and biomechanical changes. TGA treatment for three days significantly reduced collagen loss by 88% and increased thermal denaturation temperatures (Ts) above 80 degrees C versus Ts of 70 degrees C or less for non-crosslinked meniscus. In vitro, TGA and TGA-MABP significantly increased aggregate modulus by 19% and 32% compared to native controls, respectively. TGA decreased permeability by 53% while TGA-MABP increased it by 303%. In vivo, TGA significantly reduced explant calcification by 42% compared to glutaraldehyde, and including MABP reduced it by 90%. Analyses revealed that TGA and TGA-MABP stabilized menisci had significantly lower modulus and permeability values than glutaraldehyde controls by at least 28% and 86%, respectively. It is concluded that TGA crosslinking of meniscus increases resistance to both collagenase degradation and pathologic calcification, while demonstrating comparable or improved biomechanical properties versus glutaraldehyde controls.

  15. Sample preparation for thermo-gravimetric determination and thermo-gravimetric characterization of refuse derived fuel.

    PubMed

    Robinson, T; Bronson, B; Gogolek, P; Mehrani, P

    2016-02-01

    Thermo-gravimetric analysis (TGA) is a useful method for characterizing fuels. In the past it has been applied to the study of refuse derived fuel (RDF) and related materials. However, the heterogeneity of RDF makes the preparation of small representative samples very difficult and this difficulty has limited the effectiveness of TGA for characterization of RDF. A TGA method was applied to a variety of materials prepared from a commercially available RDF using a variety of procedures. Applicability of TGA method to the determination of the renewable content of RDF was considered. Cryogenic ball milling was found to be an effective means of preparing RDF samples for TGA. When combined with an effective sample preparation, TGA could be used as an alternative method for assessing the renewable content of RDF.

  16. Investigation of the Thermal Degradation of Alkyl isocyanate Polymers by Direct Pyrolysis Mass Spectroscopy

    DTIC Science & Technology

    1988-09-20

    attributed to an EI fragment originating from the isocya- nurate. Both the TIC curve and TGA analysis show that complete decompo- 4’. 0’ sition of this...contrast, the TGA analysis shows that 0J. complete decomposition is delayed until -450 C. This difference is attributed to the high vacuum conditions...the polymer are removed at lower temperature than in the TGA analysis . The TIC curve clearly shows a peak with three sharp maxima appearing at

  17. Microthermogravimetric analysis as a useful tool for in-situ planetary space missions

    NASA Astrophysics Data System (ADS)

    Palomba, E.; Zinzi, A.; Longobardo, A.; Bellucci, G.; Zampetti, E.; Pantalei, S.; Bearzotti, A.; Macagnano, A.

    2008-09-01

    Thermo gravimetric analysis (TGA) is a widely used technique to investigate condensation/sublimation and absorption/desorption processes of volatile compounds in different environments. TGA analyzers are used to investigate outgassing contamination in Space, dehydration and organic decomposition in minerals, as well as to measure moisture content in foods or develop temperature profiles for firing ceramics. TGA is often coupled with other analytical techniques (e.g., mass spectroscopy and FTIR) in order to determine the specific off-gas materials.

  18. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

    An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

  19. Structure-Stability Relationships of Polymers Based on Thermogravimetric Analysis Data. Part 1. Polyaliphatics, Polyalicyclics, Spiro Polymers and Phenylene-R-Polymers

    DTIC Science & Technology

    1974-12-01

    Polymerization 13 9. Polymers with Bridged Ring Systems 14 10. Spiro Polymers 14 11. Polyphenylene s 16 12. Phenol - Formaldehyde Resins 17 13. Polyphenylene...Oxides 18 14. Polyphenylene Sulfides 20 15. Polyphenylene Sulfones 21 16. Poly s ulfonate s 22 17. Aromatic Polyesters 23 18. Polycarbonates 26 19...Poly - 2, 6 - dimethylphenylene oxide 51 7 TGA curves of Poly-p-phenylene sulfide 52 8 TGA curves of a Polyphenyleneether sulfone 53 9 TGA curves of

  20. Synthesis of Amide Functionalized Carbon Nanotubes

    DTIC Science & Technology

    2007-01-01

    amide-linked SWNTs. Through FT-IR spectroscopy, Raman spectroscopy and TGA analysis it was proven that the intermediate compounds were successfully...analysis (TGA). Figure 4 shows the TGA data for SWNT-COOH, SWNT-NH2 and SWNT 4 at a heating rate of 10 oC/min in the presence of argon. The TGA ... analysis shows a major decline in mass for the amide- interconnected nanotubes between the 200 oC to 400 oC region. Weight loss due to functionalization

  1. Biofunctional quantum dots as fluorescence probe for cell-specific targeting.

    PubMed

    Ag, Didem; Bongartz, Rebecca; Dogan, Leyla Eral; Seleci, Muharrem; Walter, Johanna-G; Demirkol, Dilek Odaci; Stahl, Frank; Ozcelik, Serdar; Timur, Suna; Scheper, Thomas

    2014-02-01

    We describe here the synthesis, characterization, bioconjugation, and application of water-soluble thioglycolic acid TGA-capped CdTe/CdS quantum dots (TGA-QDs) for targeted cellular imaging. Anti-human epidermal growth factor receptor 2 (HER2) antibodies were conjugated to TGA-QDs to target HER2-overexpressing cancer cells. TGA-QDs and TGA-QDs/anti-HER2 bioconjugates were characterized by fluorescence and UV-Vis spectroscopy, X-ray diffraction (XRD), hydrodynamic sizing, electron microscopy, and gel electrophoresis. TGA-QDs and TGA-QDs/anti-HER2 were incubated with cells to examine cytotoxicity, targeting efficiency, and cellular localization. The cytotoxicity of particles was measured using an MTT assay and the no observable adverse effect concentration (NOAEC), 50% inhibitory concentration (IC50), and total lethal concentration (TLC) were calculated. To evaluate localization and targeting efficiency of TGA-QDs with or without antibodies, fluorescence microscopy and flow cytometry were performed. Our results indicate that antibody-conjugated TGA-QDs are well-suited for targeted cellular imaging studies.

  2. Analysis of mutations in 7 candidate genes for dextro-Transposition of the great arteries in Chinese population

    PubMed Central

    Lei, Liming; Lin, Haoming; Zhong, Shilong; Zhang, Zhiwei; Chen, Jimei; Li, Xin-Xin; Yu, Xiyong; Liu, Xaioqing

    2014-01-01

    Background Transposition of great arteries (TGA) represents the most frequent cyanotic heart defect diagnosed in the neonatal period. Several genes had been identified to be associated with the pathogenesis of dextro-transposition of the great arteries (d-TGA). These genes are located in different chromosomes and their mutations can only explain few clinical cases. Besides, no genetic scan for TGA has been implemented in China. Methods To evaluate whether aberrations in any of the 13 reported mutations in seven genes (MED13L, ZIC3, CFC1, NODAL, FOXH1, GDF1 and NKX2-5) could completely or in part be the genetic component involved in TGA in Chinese population, we screened 102 Chinese patients with d-TGA by direct sequencing for mutations within the seven genes. Results We found none of the reported 13 mutations in those 102 Chinese d-TGA patients. Conclusions These reported 13 mutations may not be a common cause of d-TGA in Chinese population due to racial variation and genetic heterogeneity of TGA. New approaches including the whole exome sequencing technology are required to effectively identify genetic variants in TGA patients in China. PMID:24822108

  3. Glycoalkaloids in potato tubers grown under controlled environments

    NASA Technical Reports Server (NTRS)

    Nitithamyong, A.; Vonelbe, J. H.; Wheeler, R. M.; Tibbitts, T. W.

    1999-01-01

    Tuber content of alpha-solanine, alpha-chaconine, and total glycoalkaloids (TGA) was determined for the potato cultivars, Norland, Russet Burbank, and Denali grown under different environmental conditions in growth chambers. The lowest TGA concentrations (0.30 to 0.35 mg g-1 dry tissue) were found in the cv. Norland with 400 micromoles m-2 s-1 photosynthetic photon flux (PPF), 12 h day length, 16 C temperature, and 350 micromoles mol-1 carbon dioxide. The ratio of alpha-chaconine to alpha-solanine was close to 60:40 under all growing conditions, except that it was 50:50 under the low temperature of 12 C. Cultivars responded similarly to environmental conditions although TGA was about 20% greater in cv. Russet Burbank and about 30% greater in Denali compared to Norland. The largest changes in TGA occurred with changes in temperature. In comparison to 16 C, TGA were 40% greater at 12 C, 80% greater at 20 C, and 125% greater at 24 C (0.70 mg g-1 dry weight). The TGA concentration increased from 10 to 25% with an increase in light from 400 to 800 micromoles m-2 s-1 PPF for all three cultivars. TGA increased 20% with extension of the day length from 12 to 24 hr and also increased 20% when carbon dioxide was increased from 350 to 1000 micromoles mol-1. TGA concentrations were not influenced by changes in relative humidity from 50 to 80%. TGA concentrations decreased only slightly in harvests made from 9 to 21 weeks after planting. Variations in TGA among the different growing conditions and cultivars were below 20 mg/100 g fresh weight (approximately 1.0 mg g-1 dry weight) recognized as the upper concentration for food safety. However the results suggest that TGA should be considered when potatoes are grown at temperatures above 20 C.

  4. Phenolic and Glycoalkaloid Levels of S. Jamesii Accessions and their Anti-Proliferative Effect on Human Prostate and Colon Cancer Cells In Vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some tuber-bearing wild potato species are higher in antioxidant activity (AOA), phenolics (TP) and glycoalkaloids (TGA >200 mg/kg) than the potato of commerce. Hence, use of wild species as parental material in breeding for high AOA and TP might result in progenies with high TGA, if the traits are ...

  5. Donor Acceptor Polymerization Chemistry as a Vehicle to Low Energy Cure of Matrix Resins: Evolution of the 2-Tg Concept to Produce High Tg Polymers at Ambient Temperatures

    DTIC Science & Technology

    1989-03-01

    tetrafunctional acceptors. DSC and TGA analysis of these polymers indicated they possessed the thermal stability necessary for performance in their...be enhanced by choosing comonomers that act as "solvents", and that the "onset of decomposition" temperature as measured by TGA analysis under nitrogen

  6. Piezoelectric Ceramics for High Temperature Actuators

    DTIC Science & Technology

    2006-04-01

    3 TGA analysis showed a weight loss of 0.17% with onset at 1030 °C upon heating (Fig. 21). Weight loss graphed in Figure 21 is normalized at 450°C...0.14 mol% which was practically equal to the theoretical amount 0.148 mol%. TGA analysis of doped compositions revealed weight loss of 0.18% during

  7. Quasi-Steady Analysis of Aircraft Panel Flammability.

    DTIC Science & Technology

    1984-06-01

    temperatures. The system also has bismaleimide as a major additional ingredient. Finally, TGA analysis of a VPSP facesheet would give a different...result from a TGA analysis of a panel specimen including a Nomex core along with the VPSP. The interpretation of the data also affords variations in the

  8. Investigation of the Ultrafiltration Technique Using Military Greases

    DTIC Science & Technology

    1993-10-01

    eith fiered sample. Table 4 shows the total solid composition of test greases which was measured at before and after filtration using TGA analysis . In...this TGA analysis , about one percent of the solid composition was filtered out of the MIL-G-8 1322D grease, while only 0.4 percent of solid was removed

  9. Dispersion of Functionalized Nanoclay Platelets in an Amine-Cured Epoxy Resin System

    DTIC Science & Technology

    2001-11-01

    another 2 h at 125 C. The same curing procedure was applied to vernolic acid mixed C18 clay. (E) FTIR and TGA Analysis of Nanoclay Powder FTIR...were rounded off to the nearest I cm 1 ) spectrophotometer. TGA analysis was performed on the Na clay, C18 clay, and vernolic acid mixed C18 clay

  10. Interim Report on Scientific Basis for Paint Stripping: Mechanism of Methylene Chloride Based Paint Removers

    DTIC Science & Technology

    2010-10-18

    satisfactory results, TGA analysis was performed to ensure the absence of nontraditional species such as inorganic additives. All coatings demonstrated...MIL-85285, preventing DSC and TGA analysis . Exposure to methylene chloride and PhOH decreases the Tg to -18 °C. Exposure to EtOH and PhOH 17

  11. Polymerization of Functionalized Norbornenes Employing Mo(CH-t-Bu)(NAr) (O-t-Bu)2 as the Initiator

    DTIC Science & Technology

    1990-12-05

    polymerized in THF straightforwardly. Proton NMR spectra of polv-8 shows it to contain 60 % trans olefinic linkages. TGA analysis reveals a Tg at 108 *C...4. TGA analysis of poiy-6. Figure 5. GPC trace of poly-I/5. Figure 6. 125 MHz 13C NMR (CDCl3 ) spectra in the olefinic region of (a) poly-5; (b) poly

  12. Effect of Coprecipitation Parameters on Powder Characteristics and on Densification of PZT Ceramics.

    DTIC Science & Technology

    1982-09-01

    34* diffraction using a Phillips Norelco Diffractometer with filtered Ni K radiati-n. The powders were also subjected to DTA and TGA analysis using... TGA analysis showed the first two peaks to be associated with weight loss, the maximum loss occurring near 300oC. From Fig. 4a it is evident that I0

  13. Synthesis of Tetra-Functional Cubane Derivatives

    DTIC Science & Technology

    1989-03-03

    cubane-1,4-diacid (Figure 15) shows a similar sharp decomposition exotherm at 246’C and a smaller unexplained exotherm at 220°C. TGA analysis revealed...in CH 2 C] 2 on a Perkin- Elmer 700 spectrometer. DSC and TGA analysis were performed on a Dupont 9900 Thermoanalyzer. 18 0 19) (0- - ~ t-4 ,10 In do

  14. Executive Function and Theory of Mind in School-Aged Children after Neonatal Corrective Cardiac Surgery for Transposition of the Great Arteries

    ERIC Educational Resources Information Center

    Calderon, Johanna; Bonnet, Damien; Courtin, Cyril; Concordet, Susan; Plumet, Marie-Helene; Angeard, Nathalie

    2010-01-01

    Aim: Cardiac malformations resulting in cyanosis, such as transposition of the great arteries (TGA), have been associated with neurodevelopmental dysfunction. The purpose of this study was to assess, for the first time, theory of mind (ToM), which is a key component of social cognition and executive functions in school-aged children with TGA.…

  15. Role of premature stop codons in bacterial evolution.

    PubMed

    Wong, Tit-Yee; Fernandes, Sanjit; Sankhon, Naby; Leong, Patrick P; Kuo, Jimmy; Liu, Jong-Kang

    2008-10-01

    When the stop codons TGA, TAA, and TAG are found in the second and third reading frames of a protein-encoding gene, they are considered premature stop codons (PSC). Deinococcus radiodurans disproportionately favored TGA more than the other two triplets as a PSC. The TGA triplet was also found more often in noncoding regions and as a stop codon, though the bias was less pronounced. We investigated this phenomenon in 72 bacterial species with widely differing chromosomal GC contents. Although TGA and TAG were compositionally similar, we found a great variation in use of TGA but a very limited range of use of TAG. The frequency of use of TGA in the gene sequences generally increased with the GC content of the chromosome, while the frequency of use of TAG, like that of TAA, was inversely proportional to the GC content of the chromosome. The patterns of use of TAA, TGA and TAG as real stop codons were less biased and less influenced by the GC content of the chromosome. Bacteria with higher chromosomal GC contents often contained fewer PSC trimers in their genes. Phylogenetically related bacteria often exhibited similar PSC ratios. In addition, metabolically versatile bacteria have significantly fewer PSC trimers in their genes. The bias toward TGA but against TAG as a PSC could not be explained either by the preferential usage of specific codons or by the GC contents of individual chromosomes. We proposed that the quantity and the quality of the PSC in the genome might be important in bacterial evolution.

  16. Incidence of transient global amnesia in Merano, province of Bolzano, Italy.

    PubMed

    Brigo, Francesco; Lochner, Piergiorgio; Tezzon, Frediano; Nardone, Raffaele

    2014-12-01

    Few community-based studies determined the incidence of transient global amnesia (TGA), with annual incidence rates between 2.9 and 10.4/100,000. Data on sex distribution of TGA are discrepant. Aim of this study was to determine the incidence of TGA in Merano, province of Bolzano, Northern Italy. Cases were identified from hospital discharge diagnoses of all the Departments of the general hospital of Merano and neighboring towns. Patients fulfilling internationally accepted diagnostic criteria for TGA and residing in Merano were included. Crude, age- and sex-specific incidence rates were computed. The overall annual crude incidence rate of TGA was 9.6/100,000 inhabitants (9.5 % confidence interval 6.7-13.3), 10.1/100,000 for men and 8.9/100,000 for women (p < 0.001). After adjustment by the direct method to the European population, the annual incidence rate was 6.4/100,000. The incidence rate of TGA in Merano, Italy, does not differ from that reported in Turku, Finland and Belluno, Italy. This study confirms that this benign syndrome is relatively common and occurs mainly in elderly patients. However, the higher male predominance in TGA incidence rates contrasts with previous epidemiological studies. Further, prospective incidence studies should therefore be conducted to further clarify sex predominance in TGA.

  17. Polymer Interaction in a Model Bioblend

    Technology Transfer Automated Retrieval System (TEKTRAN)

    EBU/PS blends of varying compositions were investigated using TGA, MDSC, and FTIR-PAS methods. The goal of the investigation was that of probing for the presence or lack of intermolecular interactions between the two polymers. The TGA investigation showed at least one blend composition with better...

  18. Can We Remember Future Actions yet Forget the Last Two Minutes? Study in Transient Global Amnesia

    ERIC Educational Resources Information Center

    Hainselin, Mathieu; Quinette, Peggy; Desgranges, Beatrice; Martinaud, Olivier; Hannequin, Didier; de La Sayette, Vincent; Viader, Fausto; Eustache, Francis

    2011-01-01

    Transient global amnesia (TGA) is a clinical syndrome characterized by the abrupt onset of a massive episodic memory deficit that spares other cognitive functions. If the anterograde dimension is known to be impaired in TGA, researchers have yet to investigate prospective memory (PM)--which involves remembering to perform an intended action at…

  19. Long-term outcome in transient global amnesia patients with and without focal hyperintensities in the CA1 region of the hippocampus.

    PubMed

    Uttner, Ingo; Prexl, Sascha; Freund, Wolfgang; Unrath, Alexander; Bengel, Dietmar; Huber, Roman

    2012-01-01

    Focal hippocampal diffusion-weighted imaging (DWI) lesion patterns are detected in transient global amnesia (TGA) patients in different frequency. It has been speculated that acute diffusion restrictions are associated with a worse outcome. Therefore, we evaluated the influence of acute DWI lesions on the cognitive long-term outcome in TGA patients. Seventeen otherwise healthy patients with the clinical syndrome of TGA, who had MRI investigations on admission as well as 1 day later, were investigated with a comprehensive neuropsychological test battery 2 years later. Acute hippocampal DWI lesions in TGA patients were detected in almost two thirds of the patients. Psychometric evaluation revealed no differences in cognitive performance between patients with and without DWI lesions as well as compared to healthy subjects. In addition, no relapse of the attack has been recognized in either group of TGA patients.

  20. Triglycidylamine Cross-linking Combined with Ethanol Inhibits Bioprosthetic Heart Valve Calcification

    PubMed Central

    Connolly, Jeanne M.; Bakay, Marina A.; Alferiev, Ivan S.; Gorman, Robert C.; Gorman, Joseph H.; Kruth, Howard S.; Ashworth, Paul E.; Kutty, Jaishankar K.; Schoen, Frederick J.; Bianco, Richard W.; Levy, Robert J.

    2012-01-01

    Background One of the most important factors responsible for the calcific failure of bioprosthetic heart valves is glutaraldehyde cross-linking. Ethanol (EtOH) incubation after glutaraldehyde cross-linking has previously been reported to confer anti-calcification efficacy for bioprostheses. The present studies investigated the anticalcification efficacy in vivo of the novel cross-linking agent, triglycidyl amine (TGA), with or without EtOH incubation, in comparison to glutaraldehyde. Methods TGA cross-linking (+/− EtOH) was used to prepare porcine aortic valves for both rat subdermal implants and sheep mitral valve replacements, for comparisons with glutaraldehyde-fixed controls. Thermal denaturation temperature (Ts), an index of cross-linking, cholesterol extraction, and hydrodynamic properties were quantified. Explant endpoints included quantitative and morphologic assessment of calcification. Results Ts after TGA were intermediate between unfixed and glutaraldehyde-fixed. EtOH incubation resulted in almost complete extraction of cholesterol from TGA or glutaraldehyde-fixed cusps. Rat subdermal explants (90days) demonstrated that TGA-EtOH resulted in a significantly greater level of inhibition of calcification than other conditions. Thus, TGA-ethanol stent mounted porcine aortic valve bioprostheses were fabricated for comparisons with glutaraldehyde-pretreated controls. In hydrodynamic studies, TGA-EtOH bioprostheses had lower pressure gradients than glutaraldehyde-fixed. TGA-ethanol bioprostheses used as mitral valve replacements in juvenile sheep (150 days) demonstrated significantly lower calcium levels in both explanted porcine aortic cusp and aortic wall samples compared to glutaraldehyde-fixed controls. However, TGA-EtOH sheep explants also demonstrated isolated calcific nodules and intracuspal hematomas. Conclusions TGA-EtOH pretreatment of porcine aortic valves confers significant calcification resistance in both rat subdermal and sheep circulatory

  1. Sleep Modifications in Acute Transient Global Amnesia

    PubMed Central

    Della Marca, Giacomo; Mazza, Marianna; Losurdo, Anna; Testani, Elisa; Broccolini, Aldobrando; Frisullo, Giovanni; Marano, Giuseppe; Morosetti, Roberta; Pilato, Fabio; Profice, Paolo; Vollono, Catello; Di Lazzaro, Vincenzo

    2013-01-01

    Study Objective: Transient global amnesia (TGA) is a temporary memory loss characterized by an abrupt onset of antero-grade and retrograde amnesia, totally reversible. Since sleep plays a major role in memory consolidation, and in the storage of memory-related traces into the brain cortex, the aims of the present study were: (1) to evaluate changes in sleep macro-structure in TGA; (2) to assess modifications in sleep micro-structure in TGA, with particular reference to the arousal EEG and to cyclic alternating pattern (CAP); (3) to compare sleep parameters in TGA patients with a control group of patients with acute ischemic events (“minor stroke” or transient ischemic attack [TIA]) clinically and neuroradiologically “similar” to the TGA. Methods: TGA group: 17 patients, (8 men and 9 women, 60.2 ± 12.5 years). Stroke or TIA (SoT) group: 17 patients hospitalized in the Stroke Unit for recent onset of minor stroke or TIA with hemispheric localization; healthy controls (HC) group: 17 healthy volunteers, matched for age and sex. Patients and controls underwent full-night polysomnography. Results: In the multivariate analysis (conditions TGA, SoT, and HC) a significant effect of the condition was observed for sleep efficiency index, number of awakenings longer 1 min, REM latency, CAP time, and CAP rate. TGA and SoT differed only for CAP time and CAP rate, which were lower in the TGA group. Conclusions: Microstructural modification associated with TGA could be consequent to: (1) hippocampal dysfunction and memory impairment; (2) impairment of arousal-related structures (in particular, cholinergic pathways); (3) emotional distress. Citation: Della Marca G; Mazza M; Losurdo A; Testani E; Broccolini A; Frisullo G; Marano G; Morosetti R; Pilato F; Profice P; Vollono C; Di Lazzaro V. Sleep modifications in acute transient global amnesia. J Clin Sleep Med 2013;9(9):921-927. PMID:23997704

  2. Photodegradation of Mercaptopropionic Acid- and Thioglycollic Acid-Capped CdTe Quantum Dots in Buffer Solutions.

    PubMed

    Miao, Yanping; Yang, Ping; Zhao, Jie; Du, Yingying; He, Haiyan; Liu, Yunshi

    2015-06-01

    CdTe quantum dots (QDs) were synthesized by 3-mercaptopropionic acid (MPA) and thioglycollic acid (TGA) as capping agents. It is confirmed that TGA and MPA molecules were attached on the surface of the QDs using Fourier transform infrared (FT-IR) spectra. The movement of the QDs in agarose gel electrophoresis indicated that MPA-capped CdTe QDs had small hydrodynamic diameter. The photoluminescence (PL) intensity of TGA-capped QDs is higher than that of MPA-capped QDs at same QD concentration because of the surface passivation of TGA. To systemically investigate the photodegradation, CdTe QDs with various PL peak wavelengths were dispersed in phosphate buffered saline (PBS) and Tris-borate-ethylenediaminetetraacetic acid (TBE) buffer solutions. It was found that the PL intensity of the QDs in PBS decreased with time. The PL peak wavelengths of the QDs in PBS solutions remained unchanged. As for TGA-capped CdTe QDs, the results of PL peak wavelengths in TBE buffer solutions indicated that S(2-) released by TGA attached to Cd(2+) and formed CdS-like clusters layer on the surface of aqueous CdTe QDs. In addition, the number of TGA on the CdTe QDs surface was more than that of MPA. When the QDs were added to buffer solutions, agents were removed from the surface of CdTe QDs, which decreased the passivation of agents thus resulted in photodegradation of CdTe QDs in buffer solutions.

  3. Higher Sensitivity and Earlier Identification of Celiac Disease Autoimmunity by a Nonradioactive Assay for Transglutaminase Autoantibodies

    PubMed Central

    Zhao, Zhiyuan; Miao, Dongmei; Waugh, Kathleen; Taki, Iman; Dong, Fran; Liu, Edwin

    2016-01-01

    Higher sensitive transglutaminase autoantibody (TGA) assay will detect the onset of celiac disease (CD) autoimmunity earlier. In developing a nonradioactive assay for TGA, we utilized electrochemiluminescence (ECL) technology and compared it to a high-performance radioimmunoassay (RIA) currently being used to screen patients with type 1 diabetes (T1D) and genetically at-risk individuals for CD. We selected 183 T1D patients with 60 patients having received biopsy and analyzed 396 sequential samples from 73 young children longitudinally followed up with TGA seroconversion, with 27 undergoing biopsy. In addition, 112 age-matched healthy control subjects were included in the study. With the 99th percentile of specificity, the ECL assay detected significantly more TGA positivity among patients with T1D (133/183) than RIA (114/183) and more of the sequential samples (34%) from 73 children than RIA (18%). The TGA assay performed by ECL was positive in all 59 subjects with villous atrophy. Among 73 longitudinally followed up children, ECL assay had earlier detection of TGA on 34 children by a mean of 2.5 years. In conclusion, the new TGA assay by ECL has a higher sensitivity than the current RIA assay and may better predict the onset of CD. PMID:28127566

  4. Transient Global Amnesia following Neural and Cardiac Angiography May Be Related to Ischemia

    PubMed Central

    Zhang, Yang; Chen, Ming; Bao, Shengde

    2016-01-01

    Introduction. Transient global amnesia (TGA) following angiography is rare, and the pathogenesis has not been illustrated clearly till now. The aim of this research is to explore the pathogenesis of TGA following angiography by analyzing our data and reviewing the literature. Methods. We retrospectively studied 20836 cases with angiography in our hospital between 2007 and 2015 and found 9 cases with TGA following angiography. The data of these 9 cases were analyzed. Results. We found all 9 cases with TGA following neural angiography (5 in 4360) or cardiac angiography (4 in 8817) and no case with TGA following peripheral angiography (0 in 7659). Statistical difference was found when comparing the neural and cardiac angiography group with peripheral group (p = 0.022). Two cases with TGA were confirmed with small acute infarctions in hippocampus after angiography. This might be related to the microemboli which were rushed into vertebral artery following blood flow during neural angiography or cardiac angiography. There was no statistical difference when comparing the different approaches for angiography (p = 0.82) and different contrast agents (p = 0.619). Conclusion. Based on the positive findings of imaging study and our analysis, we speculate that ischemia in the medial temporal lobe with the involvement of the hippocampus might be an important reason of TGA following angiography. PMID:27419129

  5. Amnestic state in a Holocaust survivor patient: psychogenic versus neurological basis.

    PubMed

    Durst, R; Teitelbaum, A; Aronzon, R

    1999-01-01

    Differentiation between psychogenic and organic amnesia is sometimes quite difficult. This paper focuses on the psychogenic and organic components of a complex case of amnesia rooted in remote and prolonged traumatic stress and manifested under circumstances evoking dissociated memories. The Transient Global Amnesia (TGA) of a concentration camp survivor who developed sudden amnesia during a psychiatric intake interview was clearly triggered by the pressure of repressed Holocaust memories. The importance of distinguishing between TGA and dissociative amnesia is emphasized, and the role of psychological upset as a precipitant in TGA is stressed.

  6. Metal-Catalyzed Alkynylation of Brominated Polyphenylenes. Thermoset Precursors of High Density Monolithic Glassy Carbon

    DTIC Science & Technology

    1993-11-22

    melting events at 152 and 1750C on the first heating scan to 2300C. While the char yield for 4a was only 50% by TGA analysis , the charred material was...after TGA analysis was also a black powder, again indicating that no flow had occurred. The char had a density of 1.59 g/cc. 1 I Polymers 16b and 16c had...material appeared as shiny black droplets after TGA analysis . The charred carbon material from 19a had a density of 1.56 g/cc. Polymers 19b and 19c

  7. Computational Design of Advanced Aeroturbine Materials: Noburnium Cyberalloy

    DTIC Science & Technology

    2004-08-01

    composition of Pd50+2yHf 25-yA125.y ( 0 _< y < 2.5 at%) over a distance of about 30 gm. The TGA analysis indicates the passive oxidation behavior of...Pd2HfAI as a function of oxidation time that was obtained from an oxidation experiment at 1300 ’C by a Thermogravimetric Analyzer (TGA). The TGA ... analysis indicates the passive oxidation behavior of Pd2HfA1 at 1300 ’C because of continuous weight gain. This implies that the inward (from surface to

  8. Novel Elastomeric Closed Cell Foam - Nonwoven Fabric Composite Material (Phase III)

    DTIC Science & Technology

    2008-10-01

    of AF07-B foams ..................................................... 10 Figure 8 TGA Analysis of AF07-A, -B and –B2B type foams...synergist to the intumescent flame retardant 5. Hybrids of the FY07-B2B and FY07-B formulas TGA analysis of AF07-A, -B and –B2B foams are shown in...Figure 8 TGA Analysis of AF07-A, -B and –B2B type foams Figure 9 shows tensile and elongation results for AF07-B2B type foams during optimization

  9. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    PubMed Central

    Toffoli, Valeria; Carrato, Sergio; Lee, Dongkyu; Jeon, Sangmin; Lazzarino, Marco

    2013-01-01

    The design and characteristics of a micro-system for thermogravimetric analysis (TGA) in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

  10. Prediction of packaging seal life using thermoanalytical techniques

    SciTech Connect

    Nigrey, P.J.

    1997-11-01

    In this study, Thermogravimetric Analysis (TGA) has been used to study silicone, Viton and Ethylene Propylene (EPDM) rubber. The studies have shown that TGA accurately predicts the relative order of thermo-oxidative stability of these three materials from the calculated activation energies. As expected, the greatest thermal stability was found in silicone rubber followed by Viton and EPDM rubber. The calculated lifetimes for these materials were in relatively close agreement with published values. The preliminary results also accurately reflect decreased thermal stability and lifetime for EPDM rubber exposed to radiation and chemicals. These results suggest TGA provides a rapid method to evaluate material stability.

  11. Identifying Hydrated Salts Using Simultaneous Thermogravimetric Analysis and Differential Scanning Calorimetry

    ERIC Educational Resources Information Center

    Harris, Jerry D.; Rusch, Aaron W.

    2013-01-01

    simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to characterize colorless, hydrated salts with anhydrous melting points less than 1100 degrees C. The experiment could be used to supplement the lecture discussing gravimetric techniques. It is…

  12. Carbon Nanotube Reinforced Polymers for Radiation Shielding Applications

    NASA Technical Reports Server (NTRS)

    Thibeault, S. (Technical Monitor); Vaidyanathan, Ranji

    2004-01-01

    This viewgraph presentation provides information on the use of Extrusion Freeform Fabrication (EEF) for the fabrication of carbon nanotubes. The presentation addresses TGA analysis, Raman spectroscopy, radiation tests, and mechanical properties of the carbon nanotubes.

  13. Fullerene carbon-70 derivatives dampen anaphylaxis and allergic asthma pathogenesis in mice

    NASA Astrophysics Data System (ADS)

    Norton, Sarah Brooke

    Fullerenes are carbon nanospheres that can be solublized by the addition of polar chemical groups to the carbon cage, forming fullerene derivatives. One specifically derivatized fullerene compound, termed C 70-Tetragylocolate (C70-TGA), has been shown to stabilize mast cell responses in vitro thus we hypothesized it may have an effect on mast cell-driven diseases such as asthma and systemic anaphylaxis. To observe the effects of C70-TGA on systemic anaphylaxis, mice were subjected to a model of passive systemic anaphylaxis. In this model, mice were injected with DNP-specific IgE 16 hours prior to challenge, then treated with C 70-TGA. Immediately prior to DNP challenge, mice were subjected to a second injection of C70-TGA. Following DNP challenge, body temperature was recorded and blood was collected for quantitation of histamine levels. Treatment with C70-TGA significantly reduced body temperature drop associated with systemic anaphylaxis and serum histamine levels. To observe the effects of C70-TGA on chronic features of asthma in vivo, we utilized a heavily MC influenced model of asthma pathogenesis. Mice were sensitized by intraperitoneal (i.p.) injection of ovalbumin (OVA) in saline, challenged intranasally (i.n.) with OVA, and one of two treatment strategies was pursued. In one, C70-TGA was given i.n. throughout disease development. In the other, C70-TGA was given following an initial set of challenges to allow disease to develop prior to treatment; mice were then re-challenged with OVA to assess the effect on established disease. We found that C70-TGA treatment significantly reduced airway inflammation and eosinophilia and dramatically reduced bronchoconstriction in either model. Cytokines IL-4 and IL-5 and serum IgE levels are significantly reduced in C70-TGA treated animals. Interestingly, we also saw an increase in the anti-inflammatory eicosanoid 11, 12-epoxyeicosatreinoic acid (11,12-EET) in the BAL fluid, suggesting the involvement of this mediator in

  14. Discussion about Possibility of Closer Collaboration or Co-authoring

    SciTech Connect

    Holcomb, Gordon R.; Matsunaga, Y.

    2012-12-04

    This slide-show presents the status of a fireside corrosion collaboration, including laboratory fireside tests, callide oxy-fuel field exposures, DTA and TGA of SCM ash, and deposit related bell-shaped boiler corrosion and DTA results.

  15. Effect of surface ligands on the optical properties of aqueous soluble CdTe quantum dots

    PubMed Central

    2012-01-01

    We investigate systematically the influence of the nature of thiol-type capping ligands on the optical and structural properties of highly luminescent CdTe quantum dots synthesized in aqueous media, comparing mercaptopropionic acid (MPA), thioglycolic acid (TGA), 1-thioglycerol (TGH), and glutathione (GSH). The growth rate, size distribution, and quantum yield strongly depend on the type of surface ligand used. While TGH binds too strongly to the nanocrystal surface inhibiting growth, the use of GSH results in the fastest growth kinetics. TGA and MPA show intermediate growth kinetics, but MPA yields a much lower initial size distribution than TGA. The obtained fluorescence quantum yields range from 38% to 73%. XPS studies unambiguously put into evidence the formation of a CdS shell on the CdTe core due to the thermal decomposition of the capping ligands. This shell is thicker when GSH is used as ligand, as compared with TGA ligands. PMID:23017183

  16. Final report for Tank 241-B-101, push mode cores 90 and 91. Revision 1

    SciTech Connect

    Schreiber, R.D.

    1995-11-01

    This is the final report for tank 241-@101, cores 90 and 91. Samples from these cores were analyzed for safety screening purposes in accordance with the Tank 241-B-101 Tank Characterization Plan (TCP) (Reference 1). This final report contains the results for three sets of TGA and gravimetric analyses performed after the 90-day report was issued. Two of these TGA/gravimetric percent water sets of analyses were done because low original TGA results were obtained for the lower half segment of core 90, segment 2 and the facie of core 91, segment 2; the third set of analyses were performed because the TGA and gravimetric percent water results for the upper half segment of core 90, segment 2 differed by approximately a factor of three and further investigation was warranted.

  17. Semantic acquisition without memories: evidence from transient global amnesia.

    PubMed

    Guillery, B; Desgranges, B; Katis, S; de la Sayette, V; Viader, F; Eustache, F

    2001-12-04

    Transient global amnesia (TGA), characterised by a profound anterograde amnesia, is a model of interest to study the acquisition of novel meanings independent of episodic functioning. Three patients were tested during a TGA attack, two in the early recovery phase and the third during the acute phase of TGA, with a semantic priming task involving a restructuring process of conceptual knowledge. During TGA, all patients demonstrated priming effects. Results obtained the day after the episode with the same task showed that these effects persisted at least one day. Episodic memory seems not to be critical for the formation of novel connections among unrelated semantic representations, in accordance with Tulving's model of memory, i.e. episodic memory is not necessary for the acquisition of semantic information.

  18. Organic functionalisation of graphene catalysed by ferric perchlorate.

    PubMed

    Yang, Lei; He, Junpo

    2014-12-25

    We have developed a method to prepare covalently functionalised graphene using ferric perchlorate as the catalyst. The resulting functionalised graphene was characterised by Raman spectroscopy, TGA, XPS, AFM, and dispersibility tests in organic or aqueous media.

  19. Extraction and characterization of montmorency (Prunus cerasus L.) sour cherry pit oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Montmorency sour cherry (Prunus cerasus L.) pit oil was extracted and characterized by various methods including: gas chromatography (GC), liquid chromatography coupled with mass spectrometry (LC-MS), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorime...

  20. Preparation of Soy Polymers by a Green Processing Method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ring opening polymerization of epoxidized soybean oil (ESO) initiated by boron trifluoride diethyl etherate was conducted in liquid carbon dioxide. The resulting polymers (RPESO) were characterized using Infrared (IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), 1H NM...

  1. Transient global amnesia associated with a unilateral infarction of the fornix: case report and review of the literature.

    PubMed

    Gupta, Mihir; Kantor, Molly A; Tung, Christie E; Zhang, Niushen; Albers, Gregory W

    2014-01-01

    Stroke is an extremely uncommon cause of transient global amnesia (TGA). Unilateral lesions of the fornix rarely cause amnesia and have not previously been reported to be associated with the distinctive amnesic picture of TGA. We describe the case of a 60-year-old woman who presented with acute onset, recent retrograde, and anterograde amnesia characteristic of TGA. Serial magnetic resonance imaging showed a persistent focal infarction of the body and left column of the fornix, without acute lesions in the hippocampus or other structures. Amnesia resolved in 6 h. Infarction of the fornix should thus be included in the differential diagnosis of TGA, as it changes the management of this otherwise self-limited syndrome.

  2. Cognitive findings after transient global amnesia: role of prefrontal cortex.

    PubMed

    Le Pira, Francesco; Giuffrida, Salvatore; Maci, Tiziana; Reggio, Ester; Zappalà, Giuseppe; Perciavalle, Vincenzo

    2005-01-01

    The aim of this study is to verify, after recovery, the presence of specific patterns of cognitive dysfunctions in Transient Global Amnesia (TGA). Fourteen patients with the diagnosis of TGA were submitted to a battery of neuropsychological tests and compared to a matched control group. We found significant qualitative and quantitative differences between TGA patients and controls in the California Verbal Learning Test (CLVT) and Rey-Osterrieth Complex Figure Test. Our data support the presence of selective cognitive dysfunctions after the clinical recovery. Moreover, for Verbal Fluency, Digit Span Backward, and Number of Clusters in the CVLT short-term memory test, the relation resulted as positively related with the temporal interval from the TGA episode. Reduction of categorical learning, attention, and qualitative alterations of spatial strategy seem to postulate a planning defect due to a prefrontal impairment.

  3. Transient global amnesia--full recovery without persistent cognitive impairment.

    PubMed

    Uttner, I; Weber, S; Freund, W; Schmitz, B; Ramspott, M; Huber, R

    2007-01-01

    Transient global amnesia (TGA) is a clinical syndrome of unknown etiology characterized by sudden onset anterograde amnesia, which was thought to resolve completely. However, some authors have also suggested permanent memory impairment. It is unclear whether these results reflect a true persistent damage or a simply too short assessment interval in the context of a prolonged recovery phase after TGA. To evaluate the cognitive long-term outcome, 16 patients who had suffered from TGA at a mean of 3 years before and 15 healthy controls underwent a comprehensive neuropsychological test battery. No significant differences between patients' and controls' cognitive performance were found, irrespectively of the analyzed neuropsychological domain. Therefore we hypothesize that TGA usually does not cause persistent cognitive deficits due to a generally transient and prognostic benign character.

  4. Thermal analysis of RFETS SS and C

    SciTech Connect

    Korinko, P.S.

    2000-02-04

    In support of the gas generation test program (GGTP) for the 9975 shipping container, thermogravimetric analysis (TGA) was conducted. The objective of this activity was to determine the moisture content as an input to the gas generation model.

  5. Synthesis and characterization of mesoporous silica functionalized with calix[4]arene derivatives.

    PubMed

    Alahmadi, Sana M; Mohamad, Sharifah; Maah, Mohd Jamil

    2012-10-23

    This work reports a new method to covalently attach calix[4]arene derivatives onto MCM-41, using a diisocyanate as a linker. The modified mesoporous silicates were characterized by fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalently attached to the mesoporous silica. The preservation of the MCM-41 channel system was checked by X-ray diffraction and nitrogen adsorption analysis.

  6. High Temperature Reactive Thermoplastic Aromatic Polyimides

    DTIC Science & Technology

    1980-04-01

    temperatures and isothermal aging studies of the polymer, as well as, Dr. E. G. Jones for mass spectra TGA analysis . iii AFWAL-TR-80-4013 TABLE OF CONTENTS...after 200 hours (Figure 6). Mass spectra TGA analysis was carried out on polymer VIIIb from room temperature to 900’C using a 4.2°C/minute heating rate

  7. Measurement System for Energetic Materials Decomposition

    DTIC Science & Technology

    2015-01-05

    Measurement System for Energetic Materials Decomposition This DURIP grant was used to purchase: 1. Q600 SDT Simultaneous DSC-TGA 2... Decomposition Report Title This DURIP grant was used to purchase: 1. Q600 SDT Simultaneous DSC-TGA 2. Pfeiffer Vacuum Benchtop Thermostar Mass...Spectrometer 3. Vision Research Phantom V12.1-8G-M high speed camera These instruments have been used to evaluate and study decomposition and

  8. Final report for tank 241-AP-108, grab samples 8AP-96-1, 8AP-96-2 and 8AP-96-FB

    SciTech Connect

    Esch, R.A.

    1996-04-19

    This document is the final report deliverable for the tank 241-AP-108 grab samples. The samples were subsampled and analyzed in accordance with the TSAP. Included in this report are the results for the Waste Compatibility analyses, with the exception of DSC and thermogravimetric analysis (TGA) results which were presented in the 45 Day report (Part 2 of this document). The raw data for all analyses, with the exception of DSC and TGA, are also included in this report.

  9. Diagnostics for the Analysis of Surface Chemistry Effects on Composite Energetic Material Reactions

    DTIC Science & Technology

    2015-10-30

    heat flow and phase change allowing chemical kinetic modeling of surface chemistry using an advanced DSC – TGA via simultaneous thermal analysis (STA...allowing chemical kinetic modeling of surface chemistry using an advanced DSC – TGA via simultaneous thermal analysis (STA). This diagnostic couples...2.00 4.00 Evan Vargas, Michelle L. Pantoya, Mohammed A Saed, Brandon L Weeks. Advanced Susceptors for Microwave Heating of Energetic Materials

  10. Field Demonstration for P-D-680 Solvent Replacement (Part II)

    DTIC Science & Technology

    1998-05-12

    24 Appendices 25 Appendix A-l. Test Protocol for Alternative P-D-680 Solvents Test Method Flash point ASTM D 56 Distillation ASTM D 86 Kauri...Butanol value ASTM D 1133 Aniline point ASTM D 611 Odor ASTM D 1298 Non-volatile residue TGA* Evaporation @ 50 °C, 20 min TGA Copper corrosion... ASTM D 130 Steel corrosion Modified ASTM D 130 VOC content EPA method 24 Relative solvency Army soil test method * Thermoaravimetric Analysis 26

  11. Synthesis, Structure and Pyrolysis of Organoaluminum Amides Derived from the Reaction of Trialkylaluminum Compounds with Ethylenediamine in a 3:2 Ration

    DTIC Science & Technology

    1990-08-01

    initially formed melt, which was found to be methane by gas chromotography . After 15 min, gas evolution ceased and a colorless glassy solid (5) remained...Both the TGA and DSC samples were loaded under inert atmosphere. The purging gas in the TGA experiments was either nitrogen which had been passed...through a BTS catalyst (BASF CO.) and a molecular sieve column to remove 02 and H2 0 respectively, or electronic grade ammonia. Gas evolution studies

  12. Development of acceptance criteria for batches of silane primer for external tank thermal protection system bonding applications

    NASA Technical Reports Server (NTRS)

    Mikes, F.

    1984-01-01

    Silane primers for use as thermal protection on external tanks were subjected to various analytic techniques to determine the most effective testing method for silane lot evaluation. The analytic methods included high performance liquid chromatography, gas chromatography, thermogravimetry (TGA), and fourier transform infrared spectroscopy (FTIR). It is suggested that FTIR be used as the method for silane lot evaluation. Chromatograms, TGA profiles, bar graphs showing IR absorbances, and FTIR spectra are presented.

  13. Working memory and executive functions in transient global amnesia.

    PubMed

    Quinette, Peggy; Guillery, Bérengère; Desgranges, Béatrice; de la Sayette, Vincent; Viader, Fausto; Eustache, Francis

    2003-09-01

    Transient global amnesia (TGA) is usually considered to produce a profound impairment of long-term episodic memory, while at the same time sparing working memory. However, this neuropsychological dissociation has rarely been examined in detail. While a few studies have assessed some components of working memory in TGA, the results that have been obtained are far from conclusive. To clarify this issue, we carried out a comprehensive investigation of working memory in 10 patients during a TGA attack. In the first study, we report the results from three patients examined with a battery of neuropsychological tests designed to assess each of the three subcomponents of Baddeley's model of working memory. In a second study, seven different patients underwent neuropsychological investigations that focused specifically on the central executive system, using a protocol derived from a study by Miyake and colleagues. Our findings showed that subcomponents of working memory, such as the phonological loop and visuo-spatial sketch pad, were spared in TGA patients. Specific executive functions that entailed inhibitory control, dual task performance, updating and shifting mechanisms were also found to be normal. However, we found significantly impaired performance for the Brown-Peterson test, and that TGA patients were significantly impaired in the recollection of their episodic memories. They also made reduced numbers of 'remember' compared with 'know' judgments in the episodic memory test several days after TGA. On the basis of our findings, it would appear that the episodic memory deficit during TGA is not related to elementary aspects of executive functioning. Our data also highlight the nature of the cognitive mechanisms involved in the Brown-Peterson task, which may well depend on long-term memory (such as the process of semantic encoding). Lastly, the selective deficit in recollective episodic memories observed in TGA may be principally related to medial temporal lobe

  14. Persistent Pulmonary Hypertension in a Neonate With Transposition of Great Arteries and Intact Ventricular Septum: A Case Report and Review of the Literature.

    PubMed

    Karimi, Mohsen; Kirshbom, Paul M; Kopf, Gary S; Steele, Margaret M; Sullivan, Jill M

    2015-07-01

    Transposition of the great arteries (TGA) with intact ventricular septum (IVS) has very favorable short- and long-term surgical outcome. Although rare, when associated with persistent pulmonary hypertension (PPH), it exhibits significant mortality risk and management challenges. We report the case of a neonate with TGA with IVS and PPH who underwent successful early surgical repair with emphasis on clinical management and review of the literature.

  15. Managing Heart Failure in Transposition of the Great Arteries

    PubMed Central

    Shah, Sangeeta; Gupta, Tripti; Ahmad, Raza

    2015-01-01

    Background Transposition of the great arteries (TGA) is a congenital heart defect that is associated with congestive heart failure, tricuspid regurgitation, and arrhythmias. Methods This review identifies and critiques the existing methods of assessing and managing TGA with a focus on right ventricular function. Results Echocardiography with novel strain methods and cardiac magnetic resonance imaging (MRI) are noninvasive imaging options, with cardiac MRI being the gold standard. Cardiopulmonary stress testing can be used to determine the severity of symptoms. For the medical management of right ventricular dysfunction in TGA, a closely monitored dosage of beta blockers and the concomitant use of diuretics for symptomatic relief have the strongest supporting data. Surgical options for patients with TGA include the insertion of a pacemaker to treat arrhythmias, which are more common in this population, or tricuspid valve replacement to alleviate systemic tricuspid regurgitation. If symptoms in a patient with TGA are not alleviated by these management techniques, more advanced options include the use of an Impella device (Abiomed), the insertion of ventricular assist devices, or orthotopic heart transplant. Conclusion Physicians managing patients with TGA should take a multidisciplinary specialist approach to decide which route to pursue (medical or surgical) and when more advanced treatment options are necessary. PMID:26413006

  16. Glycoalkaloid development during greening of fresh market potatoes (Solanum tuberosum L.).

    PubMed

    Grunenfelder, Laura A; Knowles, Lisa O; Hiller, Larry K; Knowles, N Richard

    2006-08-09

    Chlorophyll and glycoalkaloid synthesis in potato (Solanum tuberosum L.) tubers occur in direct response to light. The two processes are concurrent, but independent. Color photographic indices to subjectively grade fresh market potatoes for the extent of greening were developed under lighting conditions consistent with those of retail markets. Total glycoalkaloid (TGA) and chlorophyll accumulation for four cultivars were determined over the respective greening scales, thus calibrating the scales for TGA content. On average, TGA concentrations in complete longitudinal sections of tubers (flesh samples) were highest in Dark Red Norland followed by Russet Norkotah, Yukon Gold, and White Rose. TGA concentrations of flesh samples of White Rose and Yukon Gold tubers were somewhat variable and did not increase in direct proportion to greening level and chlorophyll content, particularly at higher levels of greening. TGA concentrations in Dark Red Norland and Russet Norkotah tubers were highly correlated (P < or = 0.001) with greening level and chlorophyll concentrations. When averaged over greening levels, skin samples contained 3.4- to 6.8-fold higher concentrations of TGAs than flesh samples, depending on the cultivar. The TGA concentration in periderm samples ranged from 37 to 160 mg/100 g of dry wt. Regardless of greening level, concentrations of TGAs in the flesh samples (including attached periderm) remained within limits presumed safe for human consumption. Discrimination of greened tubers on the basis of perceived glycoalkaloid toxicity is likely unfounded for the cultivars and greening levels studied.

  17. Transient global amnesia: a study with Tc-99m ECD SPECT shortly after symptom onset and after recovery

    PubMed Central

    Kim, Bom Sahn; Cho, Sang Soo; Choi, Joon Young; Kim, Young Hwan

    2016-01-01

    PURPOSE Transient global amnesia (TGA) is characterized by sudden loss of memory of recent events, transient inability to retain new information, and retrograde amnesia. We investigated the changes of regional cerebral blood flow in patients with TGA shortly after symptom onset and after recovery using Tc-99m-ethyl cysteinate dimer single-photon emission computed tomography (Tc-99m ECD SPECT) and statistical parametric mapping (SPM) analysis. METHODS Six right-handed patients with TGA were studied using Tc-99m ECD SPECT shortly after symptom onset and after recovery. As a control group, six healthy individuals were also studied. Images were analyzed using SPM8 using voxel-based analysis to estimate the differences between TGA patients and controls. RESULTS There was significant hypoperfusion in the left hippocampus, left thalamus, and bilateral cerebellum. In the follow-up SPECT scan, hypoperfusion in hippocampus and thalamus were restored, while hypoperfusion was noted in the temporoparietal region. CONCLUSION Our results suggest that the underlying mechanism of TGA may be temporary ischemia in the hippocampus and thalamus. There was significant restoration of perfusion in the hippocampus and thalamus after recovery from TGA. PMID:27535207

  18. Simple and Rapid Quantitative Determination of Thiol-Containing Toxicants Using Silver Nanoparticles as an Affinity Probe

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Tapadia, K.

    2017-01-01

    A rapid and low-cost nano-drop spectrophotometric method using citrate-modified silver nanoparticles (Ag NPs) for the determination of thiol-containing toxicants was developed. The introduction of thioglycolic acid (TGA) and thiourea (TU) reduced the overall surface charge of Ag NPs, resulting in aggregation of Ag NPs, and a colorimetric response that was individually correlated with the concentration of TGA and TU. Under optimum experimental conditions, the maximum molar absorptivity values for TGA and TU were 1.04 × 105 and 2.13 × 105 L × mol-1 × cm-1, respectively, at λmax of 415 nm. The linear range used was 0.5-2.5 mg/L for TGA, and 0.3-1.5 mg/L for TU. The detection limits (3S) and % relative standard deviation (RSD) for the method were found to be 3 ppb, 2 ppb, and ±1.13%, ±0.96% for TGA and TU, respectively. This new chromogenic method provided a facile and sensitive scheme for the determination of TGA and TU, and could be applied for the determination of thiol-containing biomolecules. This scheme was tested for the analysis of real samples such as urine, blood, and environmental samples.

  19. Longitudinal Cerebral Perfusion Change in Transient Global Amnesia Related to Left Posterior Medial Network Disruption

    PubMed Central

    Jang, Jae-Won; Park, Young Ho; Park, So Young; Wang, Min Jeong; Lim, Jae-Sung; Kim, Sung-Hun; Chun, In KooK; Yang, Youngsoon; Kim, SangYun

    2015-01-01

    Background The pathophysiology of transient global amnesia (TGA) is not fully understood. Previous studies using single photon emission computed tomography (SPECT) have reported inconclusive results regarding cerebral perfusion. This study was conducted to identify the patterns of regional cerebral blood flow (rCBF) in TGA patients via longitudinal SPECT analysis. An association between the observed SPECT patterns and a pathophysiological mechanism was considered. Methods Based on the TGA registry database of Seoul National University Bundang Hospital, 22 TGA patients were retrospectively identified. The subjects underwent initial Tc-99m-ethyl cysteinate dimer (ECD) SPECT within 4 days of an amnestic event and underwent follow-up scans approximately 6 months later. The difference in ECD uptake between the two scans was measured via voxel-based whole brain analysis, and the quantified ECD uptake was tested using a paired t-test. Results The TGA patients had significantly decreased cerebral perfusion at the left precuneus (P<0.001, uncorrected) and at the left superior parietal and inferior temporal gyrus according to the voxel-based whole brain analysis (P<0.005, uncorrected). A difference in the quantified ECD uptake between the 2 scans was also found at the left precuneus among the 62 cortical volumes of interest (P = 0.018, Cohen’s d = -0.25). Conclusion We identified left hemispheric lateralized hypoperfusion that may be related to posterior medial network disruption. These findings may be a contributing factor to the pathophysiology of TGA. PMID:26690067

  20. [32 years of Senning's correction for transposition of the great vessels].

    PubMed

    Genoni, M; von Segesser, L; Wilhelm, M; Arbenz, U; Turina, M

    1996-01-01

    Between 1962 and 1994 342 patients with transposition of the great arteries (TGA) were treated by atrial correction. Since 1992 the atrial switch operation is the treatment of choice for TGA. We reviewed our 32 year experience. Average age of the patients at operation was 69 months (7 days--8.5 years). 177/342 (52%) patients had a complex TGA: 74 patients with ventricular septal defect (VSD), 49 patients with pulmonary stenosis (PS) and 54 with both (VSD and PS). The 30 day mortality was for the whole series 15.7%. In the last 4 years 7.5%. The actuarial survival rate for all patients was 88% after 10 years and 82% after 20 years. For simple TGA 91% after 10 years and 83% after 20 years, for complex TGA 84% and 81%. The most important cause of death during our longterm observation were heart failure (19 patients) and sudden death (7 patients). Average follow-up for the whole group was 13.4 years. Most of the survivors are functionally symptom free (66% NYHA I) or they have slight symptoms (29% NYHA II). Only 5% were NYHA III or IV. Arterial switch operation has replaced the atrial correction for TGA. Nevertheless the longterm results after atrial correction remains encouraging. The main threat to the patients is the failure of the systemic ventricle.

  1. Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry.

    PubMed

    Duemichen, E; Braun, U; Senz, R; Fabian, G; Sturm, H

    2014-08-08

    For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS.

  2. Autonomic Nervous System Function in Infants with Transposition of the Great Arteries

    PubMed Central

    Harrison, Tondi M.; Brown, Roger L.

    2011-01-01

    The ability to maintain homeostasis and respond to challenges to homeostasis is primarily a function of the autonomic nervous system (ANS) and may be impaired in infants with complex congenital heart defects. This study described change in ANS function before and after surgical correction in infants with transposition of the great arteries (TGA) and in healthy infants. Fifteen newborn infants with TGA were matched with 16 healthy infants on age, gender, and feeding type. ANS function was measured using heart rate variability (HRV). Data were collected pre-operatively in the first week of life and post-operatively before, during, and after feeding at two weeks and two months of age. At baseline, infants with TGA demonstrated significantly lower high frequency and low frequency HRV pre-operatively (p <.001) when compared with healthy infants. At two weeks, infants with TGA were less likely than healthy infants to demonstrate adaptive changes in high frequency HRV during-feeding (Wald Z = 2.002, p = .045), and at two months, 40% of TGA infants exhibited delayed post-feeding recovery. Further research is needed to more thoroughly describe mechanisms of a physiologically adaptive response to feeding and to develop nursing interventions supportive of these high risk infants. PMID:21613339

  3. A novel quantification method of pantaprazole sodium monohydrate in sesquihydrate by thermogravimetric analyzer.

    PubMed

    Reddy, V Ranga; Rajmohan, M Anantha; Shilpa, R Laxmi; Raut, Dilip M; Naveenkumar, Kolla; Suryanarayana, M V; Mathad, Vijayavitthal T

    2007-04-11

    To demonstrate the applicability of thermogravimetric analyzer as a tool for the quantification of pantaprazole sodium monohydrate in sesquihydrate, studies have been conducted. Thermal analysis (DSC, TGA) crystallographic (PXRD) and spectroscopic techniques (FT-IR) were used for the characterization of the polymorphs. Thermogravimetric analysis (TGA) analysis was explored by high-resolution dynamic (Hi-Res-dynamic) and high-resolution modulated (Hi-Res-modulated) test procedures to quantify the hydrate polymorphic mixtures. The two polymorphic forms exhibited significant differences and good resolution in the second derivative thermogram generated by Hi-Res-modulated test procedure. Thus, the TGA with Hi-Res-modulated test procedure was considered for the quantification of monohydrate in sesquihydrate. The calibration plot was constructed from the known mixtures of two polymorphs by plotting the peak area of the second derivative thermogram against the weight percent of monohydrate. Using this novel approach, 1 wt% limit of detection (LOD) was achieved. The polymorphic purity results, obtained by TGA in Hi-Res-modulated test procedure were found to be in good agreement with the results predicted by FT-IR and was comparable with the actual values of the known polymorphic mixtures. The Hi-Res-modulated TGA technique is very simple and easy to perform the analysis.

  4. Coal liquefaction process streams characterization and evaluation

    SciTech Connect

    Ibrahim, M.M.; Seehra, M.S. . Dept. of Physics)

    1992-10-01

    This study demonstrated the feasibility of using temperature-programmed electron spin resonance (ESR) and thermogravimetric analysis (TGA) for the examination of tetrahydrofuran (THF)-soluble distillation resid materials derived from direct coal liquefaction. TGA is used to quantitate volatile losses in a temperature-programmed experiment. The TGA data are used to correct the free radical densities obtained by ESR as volatile material is evolved from the samples in the temperature-programmed ESR experiment. The techniques, when employed in tandem, can be used to determine the content and nature of the free radicals in the samples at temperatures approximating those used in the liquefaction process. TGA and ESR experiments were performed in flowing nitrogen and hydrogen, at ambient pressure. No significant difference was observed in the ESR spectra in the different atmospheres, except in the case of low-rank coal-derived resids. The TGA results, however, were systematically different; mass loss in an H[sub 2] atmosphere is consistently higher than that observed in an N[sub 2] atmosphere. It was shown that temperature-programmed ESR, which can pinpoint conditions at which the free radical content is the highest, has potential to be a guide for the appropriate choice of conditions for optimum resid upgrading. Further development of these combined analytical methods as process development tools appears justified based on these results.

  5. Coal liquefaction process streams characterization and evaluation. Characterization of coal liquefaction resids employing thermogravimetric analysis and electron spin resonance spectroscopy

    SciTech Connect

    Ibrahim, M.M.; Seehra, M.S.

    1992-10-01

    This study demonstrated the feasibility of using temperature-programmed electron spin resonance (ESR) and thermogravimetric analysis (TGA) for the examination of tetrahydrofuran (THF)-soluble distillation resid materials derived from direct coal liquefaction. TGA is used to quantitate volatile losses in a temperature-programmed experiment. The TGA data are used to correct the free radical densities obtained by ESR as volatile material is evolved from the samples in the temperature-programmed ESR experiment. The techniques, when employed in tandem, can be used to determine the content and nature of the free radicals in the samples at temperatures approximating those used in the liquefaction process. TGA and ESR experiments were performed in flowing nitrogen and hydrogen, at ambient pressure. No significant difference was observed in the ESR spectra in the different atmospheres, except in the case of low-rank coal-derived resids. The TGA results, however, were systematically different; mass loss in an H{sub 2} atmosphere is consistently higher than that observed in an N{sub 2} atmosphere. It was shown that temperature-programmed ESR, which can pinpoint conditions at which the free radical content is the highest, has potential to be a guide for the appropriate choice of conditions for optimum resid upgrading. Further development of these combined analytical methods as process development tools appears justified based on these results.

  6. Safeners recruit multiple signalling pathways for the orchestrated induction of the cellular xenobiotic detoxification machinery in Arabidopsis.

    PubMed

    Behringer, Carina; Bartsch, Klaus; Schaller, Andreas

    2011-11-01

    Safeners enhance herbicide tolerance in crop plants but not in target weeds, thus improving herbicide selectivity. The safeners isoxadifen-ethyl and mefenpyr-diethyl protect cereal crops from sulfonyl urea herbicides in postemergence application. The two safeners were shown here to induce the cellular xenobiotic detoxification machinery in Arabidopsis thaliana when applied to leaves in a way mimicking field application. Gene expression profiling revealed the induction of 446 genes potentially involved in the detoxification process. Transgenic Arabidopsis plants expressing a reporter gene under control of a safener-responsive maize promoter were used as a model system to study the safener signalling pathway. Reporter gene analysis in the tga2/3/5/6, sid2-2 and npr1 mutants as compared with the wild-type background showed that safener inducibility required TGA transcription factors and salicylic acid (SA) in a NON-EXPRESSOR of PR-1 (NPR1)-independent pathway converging on two as-1 promoter elements. For the majority of the safener-responsive Arabidopsis genes, a similar dependence on TGA transcription factors and/or SA was shown by gene expression profiling in wild-type plants as compared with the tga2/3/5/6 and sid2-2 mutants. Thirty-eight percent of the genes, however, were induced by safeners in a TGA/SA-independent manner. These genes are likely to be controlled by WRKY transcription factors and cognate W-boxes in their promoters.

  7. Fluorescent reversible regulation based on the interactions of topotecan hydrochloride, neutral red and quantum dots.

    PubMed

    Wang, Linlin; Shen, Yizhong; Liu, Shaopu; Yang, Jidong; Liang, Wanjun; Li, Dan; He, Youqiu

    2015-02-05

    The interactions of topotecan hydrochloride (THC), neutral red (NR) and thioglycolic acid (TGA) capped CdTe/CdS quantum dots (QDs) built a solid base for the controlling of the fluorescent reversible regulation of the system. This study was developed by means of ultraviolet-visible (UV-vis) absorption, fluorescence (FL), resonance Rayleigh scattering (RRS) spectroscopy and transmission electron microscopy (TEM). Corresponding experimental results revealed that the fluorescence of TGA-CdTe/CdS QDs could be effectively quenched by NR, while the RRS of the QDs enhanced gradually with the each increment of NR concentration. After the addition of THC, the strong covalent conjugation between NR and THC which was in carboxylate state enabled NR to be dissociated from the surface of TGA-CdTe/CdS QDs to form more stable complex with THC, thereby enhancing the fluorescence of the TGA-CdTe/CdS QDs-NR system. What is more, through analyzing the optical properties and experimental data of the reaction between TGA-CdTe/CdS QDs and NR, the possible reaction mechanism of the whole system was discussed. This combination of multiple spectroscopic techniques could contribute to the investigation for the fluorescent reversible regulation of QDs and a method could also be established to research the interactions between camptothecin drugs and dyes.

  8. Fluorescent reversible regulation based on the interactions of topotecan hydrochloride, neutral red and quantum dots

    NASA Astrophysics Data System (ADS)

    Wang, Linlin; Shen, Yizhong; Liu, Shaopu; Yang, Jidong; Liang, Wanjun; Li, Dan; He, Youqiu

    2015-02-01

    The interactions of topotecan hydrochloride (THC), neutral red (NR) and thioglycolic acid (TGA) capped CdTe/CdS quantum dots (QDs) built a solid base for the controlling of the fluorescent reversible regulation of the system. This study was developed by means of ultraviolet-visible (UV-vis) absorption, fluorescence (FL), resonance Rayleigh scattering (RRS) spectroscopy and transmission electron microscopy (TEM). Corresponding experimental results revealed that the fluorescence of TGA-CdTe/CdS QDs could be effectively quenched by NR, while the RRS of the QDs enhanced gradually with the each increment of NR concentration. After the addition of THC, the strong covalent conjugation between NR and THC which was in carboxylate state enabled NR to be dissociated from the surface of TGA-CdTe/CdS QDs to form more stable complex with THC, thereby enhancing the fluorescence of the TGA-CdTe/CdS QDs-NR system. What is more, through analyzing the optical properties and experimental data of the reaction between TGA-CdTe/CdS QDs and NR, the possible reaction mechanism of the whole system was discussed. This combination of multiple spectroscopic techniques could contribute to the investigation for the fluorescent reversible regulation of QDs and a method could also be established to research the interactions between camptothecin drugs and dyes.

  9. Metabolic alterations and neurodevelopmental outcome of infants with transposition of the great arteries.

    PubMed

    Park, I Sook; Yoon, S Young; Min, J Yeon; Kim, Y Hwue; Ko, J Kok; Kim, K Soo; Seo, D Man; Lee, J Hee

    2006-01-01

    Abnormal neurodevelopment has been reported for infants who were born with transposition of the great arteries (TGA) and underwent arterial switch operation (ASO). This study evaluates the cerebral metabolism of TGA infants at birth and before ASO and neurodevelopment 1 year after ASO. Proton magnetic resonance spectroscopy (1H-MRS) was performed on 16 full-term TGA brains before ASO within 3-6 days after birth. The brain metabolite ratios of [NAA/Cr], [Cho/Cr], and [mI/Cr] evaluated measured. Ten infants were evaluated at 1 year using the Bayley Scales of Infants Development II (BSED II). Cerebral metabolism of infants with TGA was altered in parietal white matter (PWM) and occipital gray matter (OGM) at birth before ASO. One year after ASO, [Cho/Cr] in PWM remained altered, but all metabolic ratios in OGM were normal. The results of BSID II at 1 year showed delayed mental and psychomotor development. This delayed neurodevelopmental outcome may reflect consequences of the altered cerebral metabolism in PWM measured by 1H-MRS. It is speculated that the abnormal hemodynamics due to TGA in utero may be responsible for the impaired cerebral metabolism and the subsequent neurodevelopmental deficit.

  10. Ion Doped Quantum Well Lasers

    DTIC Science & Technology

    1993-04-01

    5 3 TGA analysis of {N[Si(CH3)312)3Er ................................. 5 4 Spectroscopic analysis of {N[Si(CH3)3]2)3Er...40o 56o 6oo TEMPERATURE (-C) Figure 3 TGA analysis of Er{NISi(CH3)3J]J 3 . CHEMICAL VAPOR DEPOSITION As the objective of this work is to dope A1GaAs...laO0 23633 47.870C 99.37% 1,14.84*C s00, • 95.212 173.75C 90.622 EI 800.77C 20- 60- 2o256. tC 0 i9o 360 460 560 600 TEMPERATURE (’C) Figure 3 TGA

  11. The Influence of Thermal Expansion and Mass Loss on the Young's Modulus of Ceramics During Firing

    NASA Astrophysics Data System (ADS)

    Štubňa, Igor; Trník, Anton; Podoba, Rudolf; Ondruška, Ján; Vozár, Libor

    2014-10-01

    During the heating stage of the firing of a ceramic material, the mass , length , and diameter of the sample alter their values depending on the temperature . Young's modulus measured by a sonic resonance method is also a function of the resonance frequency . Therefore, three thermal analyses (TGA, TDA, modulated force TMA) must be performed to obtain correct values of Young's modulus. The calculation of Young's modulus can be simplified if TGA and/or TDA are omitted. This necessarily leads to partly incorrect results. If TGA is not performed, we have and the relative difference reaches 7 % for and less than 2 % for . If TDA is not performed, we have and the relative difference ( is less than 0.6 % for . For the simplest case, we have and the relative difference ( is 7.5 % for and less than 2 % for.

  12. Thermal stability of the oxygen ion conductor BICUVOX.10 in different gaseous atmospheres

    SciTech Connect

    Breiter, M.W.; Reiselhuber, K.; Dorner, G.

    1995-12-31

    A study of the thermal stability of the oxygen ion conductor BICUVOX.10 was carried out on small pieces of the polycrystalline material by combined TGA and DTA measurements in air, nitrogen, oxygen and helium. The TGA measurements demonstrated that the weight change was less than 0.1% in the different gases. The DTA curves were practically the same. There is evidence for the occurrence of a phase change. TGA curves were also taken on BICUVOX.10, the parent compound Bi{sub 4}V{sub 2}O{sub 11} and the oxides CuO, B{sub 2}O{sub 3}, V{sub 2}O{sub 5} under hydrogen. The comparison of the reduction curves shows that BICUVOX.10 is stable up to about 550 C with respect to a direct reduction by molecular hydrogen.

  13. A thermogravimetric analysis of the combustion kinetics of karanja (Pongamia pinnata) fruit hulls char.

    PubMed

    Islam, Md Azharul; Auta, M; Kabir, G; Hameed, B H

    2016-01-01

    The combustion characteristics of Karanj fruit hulls char (KFH-char) was investigated with thermogravimetry analysis (TGA). The TGA outlined the char combustion thermographs at a different heating rate and isoconversional methods expressed the combustion kinetics. The Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods authenticated the char average activation energy at 62.13 and 68.53kJ/mol respectively, enough to derive the char to burnout. However, the Coats-Redfern method verified the char combustion via complex multi-step mechanism; the second stage mechanism has 135kJ/mol average activation energy. The TGA thermographs and kinetic parameters revealed the adequacy of the KFH-char as fuel substrate than its precursor, Karanj fruit hulls (KFH).

  14. Studies on thermal properties of selected aprotic and protic ionic liquids

    SciTech Connect

    Luo, Huimin; Dai, Sheng; Huang, Jing-Fang

    2008-01-01

    We describe herein the thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) investigations of the thermal properties of selected room-temperature ionic liquids (RTILs). The dependence of the thermal properties on both cation and anion structures of RTILs was systematically studied. The ionic liquids (ILs) investigated here include 28 different imidazolium-based ILs, 22 ammonium-based ILs, and 16 amide-based ILs. In general, these three cation classes exhibit different thermal behaviors but follow a quite systematic trend as expected from the corresponding structural variation. The ILs with bromide as the conjugate anion have lower thermal stabilities than those with bis(trifluoromethane sulfonyl) imide or bis(perfluoroethyl sulfonyl) imide as the conjugate anion. The mass of TGA samples and scan rate were found to have a systematic effect on the decomposition temperature of ILs, highlighting the caution needed in reporting TGA results.

  15. Measurement of volatile concentrations in volcanic glasses using thermogravimetric analysis: comparison with micro-analytical methods

    NASA Astrophysics Data System (ADS)

    Tuffen, H.; Owen, J.; Applegarth, L. J.

    2012-04-01

    Thermogravimetric analysis-mass spectrometry (TGA-MS) is potentially a powerful tool for measurement of multi-species volatile concentrations in volcanic rock samples and characterisation of degassing patterns that relate to volatile speciation. Simultaneous differential scanning calorimetry (DSC) provides information on thermal transformations such as crystallisation or melting. However no study has addressed whether the TGA technique can be used to quantify water speciation or separate water from other volatile species such as halogens. We have carried out TGA-DSC-MS experiments on a suite of compositionally homogeneous, variably-degassed rhyolitic obsidian samples from Blahnukur, Torfajökull, Iceland[1]. Sample water contents, as measured by infra-red spectroscopy, range from 0.19-0.81 wt %; F and Cl concentrations, measured using electron microprobe, range from 0.26-0.35 and 0.18-0.22 wt % respectively. Other volatile species concentrations (e.g. CO2, S) were beneath detection limits. The TGA results show an excellent correlation between the total volatile content measured using TGA (TVCTGA) and the total volatile content (H2OT + F + Cl) measured by other techniques (TVCTGA = 0.992TVCFTIR,EPMA, with R2 = 0.94). This shows that both water and halogen species are degassed during TGA measurements, even though halogen species are not detected through MS analyses. Patterns of volatile release indicate a link between water speciation, as measured using FTIR, and the temperature of degassing, and allow identification of hydrated samples. There are strong correlations between TGA weight loss over the 250-550 ° C interval and [H2Om] concentration, and between weight loss >550 ° C and the -OH content. The total volatile loss above 550 ° C far exceeds -OH concentrations alone (TGA>550 = 1.9126 [-OH] + 0.1693), but closely matches the sum of -OH, F and Cl in glasses, with TGA>550= 1.02 [-OH+F+Cl]. This indicates that halogen release occurs at high temperatures and

  16. Modeling of the devolatilization kinetics during pyrolysis of grape residues.

    PubMed

    Fiori, Luca; Valbusa, Michele; Lorenzi, Denis; Fambri, Luca

    2012-01-01

    Thermo-gravimetric analysis (TGA) was performed on grape seeds, skins, stalks, marc, vine-branches, grape seed oil and grape seeds depleted of their oil. The TGA data was modeled through Gaussian, logistic and Miura-Maki distributed activation energy models (DAEMs) and a simpler two-parameter model. All DAEMs allowed an accurate prediction of the TGA data; however, the Miura-Maki model could not account for the complete range of conversion for some substrates, while the Gaussian and logistic DAEMs suffered from the interrelation between the pre-exponential factor k0 and the mean activation energy E0--an obstacle that can be overcome by fixing the value of k0 a priori. The results confirmed the capabilities of DAEMs but also highlighted some drawbacks in their application to certain thermodegradation experimental data.

  17. SU-D-9A-02: Relative Effects of Threshold Choice and Spatial Resolution Modeling On SUV and Volume Quantification in F18-FDG PET Imaging of Anal Cancer Patients

    SciTech Connect

    Zhao, F; Bowsher, J; Palta, M; Czito, B; Willett, C; Yin, F

    2014-06-01

    Purpose: PET imaging with F18-FDG is utilized for treatment planning, treatment assessment, and prognosis. A region of interest (ROI) encompassing the tumor may be determined on the PET image, often by a threshold T on the PET standard uptake values (SUVs). Several studies have shown prognostic value for relevant ROI properties including maximum SUV value (SUVmax), metabolic tumor volume (MTV), and total glycolytic activity (TGA). The choice of threshold T may affect mean SUV value (SUVmean), MTV, and TGA. Recently spatial resolution modeling (SRM) has been introduced on many PET systems. SRM may also affect these ROI properties. The purpose of this work is to investigate the relative influence of SRM and threshold choice T on SUVmean, MTV, TGA, and SUVmax. Methods: For 9 anal cancer patients, 18F-FDG PET scans were performed prior to treatment. PET images were reconstructed by 2 iterations of Ordered Subsets Expectation Maximization (OSEM), with and without SRM. ROI contours were generated by 5 different SUV threshold values T: 2.5, 3.0, 30%, 40%, and 50% of SUVmax. Paired-samples t tests were used to compare SUVmean, MTV, and TGA (a) for SRM on versus off and (b) between each pair of threshold values T. SUVmax was also compared for SRM on versus off. Results: For almost all (57/60) comparisons of 2 different threshold values, SUVmean, MTV, and TGA showed statistically significant variation. For comparison of SRM on versus off, there were no statistically significant changes in SUVmax and TGA, but there were statistically significant changes in MTV for T=2.5 and T=3.0 and in SUVmean for all T. Conclusion: The near-universal statistical significance of threshold choice T suggests that, regarding harmonization across sites, threshold choice may be a greater concern than choice of SRM. However, broader study is warranted, e.g. other iterations of OSEM should be considered.

  18. Peripheral Endothelial Function After Arterial Switch Operation for D-looped Transposition of the Great Arteries.

    PubMed

    Sun, Heather Y; Stauffer, Katie Jo; Nourse, Susan E; Vu, Chau; Selamet Tierney, Elif Seda

    2017-03-27

    Coronary artery re-implantation during arterial switch operation in patients with D-looped transposition of the great arteries (D-TGA) can alter coronary arterial flow and increase shear stress, leading to local endothelial dysfunction, although prior studies have conflicting results. Endothelial pulse amplitude testing can predict coronary endothelial dysfunction by peripheral arterial testing. This study tested if, compared to healthy controls, patients with D-TGA after arterial switch operation had peripheral endothelial dysfunction. Patient inclusion criteria were (1) D-TGA after neonatal arterial switch operation; (2) age 9-29 years; (3) absence of known cardiovascular risk factors such as hypertension, diabetes, hypercholesterolemia, vascular disease, recurrent vasovagal syncope, and coronary artery disease; and (4) ability to comply with overnight fasting. Exclusion criteria included (1) body mass index ≥85th percentile, (2) use of medications affecting vascular tone, or (3) acute illness. We assessed endothelial function by endothelial pulse amplitude testing and compared the results to our previously published data in healthy controls (n = 57). We tested 20 D-TGA patients (16.4 ± 4.8 years old) who have undergone arterial switch operation at a median age of 5 days (0-61 days). Endothelial pulse amplitude testing indices were similar between patients with D-TGA and controls (1.78 ± 0.61 vs. 1.73 ± 0.54, p = 0.73).In our study population of children and young adults, there was no evidence of peripheral endothelial dysfunction in patients with D-TGA who have undergone arterial switch operation. Our results support the theory that coronary arterial wall thickening and abnormal vasodilation reported in these patients is a localized phenomenon and not reflective of overall atherosclerotic burden.

  19. Increased angiotensin II contraction of the uterine artery at early gestation in a transgenic model of hypertensive pregnancy is reduced by inhibition of endocannabinoid hydrolysis.

    PubMed

    Pulgar, Victor M; Yamaleyeva, Liliya M; Varagic, Jasmina; McGee, Carolynne M; Bader, Michael; Dechend, Ralf; Howlett, Allyn C; Brosnihan, K Bridget

    2014-09-01

    Increased vascular sensitivity to angiotensin II (Ang II) is a marker of a hypertensive human pregnancy. Recent evidence of interactions between the renin-angiotensin system and the endocannabinoid system suggests that anandamide and 2-arachidonoylglycerol may modulate Ang II contraction. We hypothesized that these interactions may contribute to the enhanced vascular responses in hypertensive pregnancy. We studied Ang II contraction in isolated uterine artery (UA) at early gestation in a rat model that mimics many features of preeclampsia, the transgenic human angiotensinogen×human renin (TgA), and control Sprague-Dawley rats. We determined the role of the cannabinoid receptor 1 by blockade with SR171416A, and the contribution of anandamide and 2-arachidonoylglycerol degradation to Ang II contraction by inhibiting their hydrolyzing enzyme fatty acid amide hydrolase (with URB597) or monoacylglycerol lipase (with JZL184), respectively. TgA UA showed increased maximal contraction and sensitivity to Ang II that was inhibited by indomethacin. Fatty acid amide hydrolase blockade decreased Ang IIMAX in Sprague-Dawley UA, and decreased both Ang IIMAX and sensitivity in TgA UA. Monoacylglycerol lipase blockade had no effect on Sprague-Dawley UA and decreased Ang IIMAX and sensitivity in TgA UA. Blockade of the cannabinoid receptor 1 in TgA UA had no effect. Immunolocalization of fatty acid amide hydrolase and monoacylglycerol lipase showed a similar pattern between groups; fatty acid amide hydrolase predominantly localized in endothelium and monoacylglycerol lipase in smooth muscle cells. We demonstrated an increased Ang II contraction in TgA UA before initiation of the hypertensive phenotype. Anandamide and 2-arachidonoylglycerol reduced Ang II contraction in a cannabinoid receptor 1-independent manner. These renin-angiotensin system-endocannabinoid system interactions may contribute to the enhanced vascular reactivity in early stages of hypertensive pregnancy.

  20. Detecting the Hormonal Pathways in Oilseed Rape behind Induced Systemic Resistance by Trichoderma harzianum TH12 to Sclerotinia sclerotiorum

    PubMed Central

    Alkooranee, Jawadayn Talib; Aledan, Tamarah Raad; Ali, Ali Kadhim; Lu, Guangyuan; Zhang, Xuekun; Wu, Jiangsheng; Fu, Chunhua

    2017-01-01

    Plants have the ability to resist pathogen attack after infection or treatment with biotic and abiotic elicitors. In oilseed rape plant Brassica napus AACC and in the artificially synthesized Raphanus alboglabra RRCC, the root-colonizing Trichoderma harzianum TH12 fungus triggers induced systemic resistance (ISR), and its culture filtrate (CF) triggers a systemic acquired resistance (SAR) response against infection by the Sclerotinia sclerotiorum. Salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) are plant hormone signals that play important roles in the regulation of ISR and SAR. In this study, at six different time points (1, 2, 4, 6, 8 and 10 days post-infection [dpi]), six resistance genes were used as markers of signaling pathways: JA/ET signaling used AOC3, PDF1.2 and ERF2 genes, while PR-1, TGA5 and TGA6 genes were used as markers of SA signaling. The results of quantitative real-time polymerase chain reaction (qRT-PCR) showed that AOC3, PDF1.2 and ERF2 expression levels in infected leaves of AACC and RRCC increase at 1 and 2 dpi with S. sclerotiorum or inoculation with TH12. PR-1, TGA5 and TGA6 expression levels increased at 8 and 10 dpi in infected leaves. PR-1, TGA5 and TGA6 expression levels increased early in plants treated with CF in both of the healthy genotypes. Furthermore, induction of SA- and JA/ET-dependent defense decreased disease symptoms in infected leaves at different times. The results suggest that the RRCC genotype exhibits resistance to disease and that the ability of TH12 and its CF to induce systemic resistance in susceptible and resistant oilseed rape genotypes exists. In addition, the results indicate for the first time that in RRCC the SA signaling pathway is involved in resistance to necrotrophic pathogens. PMID:28045929

  1. Detecting the Hormonal Pathways in Oilseed Rape behind Induced Systemic Resistance by Trichoderma harzianum TH12 to Sclerotinia sclerotiorum.

    PubMed

    Alkooranee, Jawadayn Talib; Aledan, Tamarah Raad; Ali, Ali Kadhim; Lu, Guangyuan; Zhang, Xuekun; Wu, Jiangsheng; Fu, Chunhua; Li, Maoteng

    2017-01-01

    Plants have the ability to resist pathogen attack after infection or treatment with biotic and abiotic elicitors. In oilseed rape plant Brassica napus AACC and in the artificially synthesized Raphanus alboglabra RRCC, the root-colonizing Trichoderma harzianum TH12 fungus triggers induced systemic resistance (ISR), and its culture filtrate (CF) triggers a systemic acquired resistance (SAR) response against infection by the Sclerotinia sclerotiorum. Salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) are plant hormone signals that play important roles in the regulation of ISR and SAR. In this study, at six different time points (1, 2, 4, 6, 8 and 10 days post-infection [dpi]), six resistance genes were used as markers of signaling pathways: JA/ET signaling used AOC3, PDF1.2 and ERF2 genes, while PR-1, TGA5 and TGA6 genes were used as markers of SA signaling. The results of quantitative real-time polymerase chain reaction (qRT-PCR) showed that AOC3, PDF1.2 and ERF2 expression levels in infected leaves of AACC and RRCC increase at 1 and 2 dpi with S. sclerotiorum or inoculation with TH12. PR-1, TGA5 and TGA6 expression levels increased at 8 and 10 dpi in infected leaves. PR-1, TGA5 and TGA6 expression levels increased early in plants treated with CF in both of the healthy genotypes. Furthermore, induction of SA- and JA/ET-dependent defense decreased disease symptoms in infected leaves at different times. The results suggest that the RRCC genotype exhibits resistance to disease and that the ability of TH12 and its CF to induce systemic resistance in susceptible and resistant oilseed rape genotypes exists. In addition, the results indicate for the first time that in RRCC the SA signaling pathway is involved in resistance to necrotrophic pathogens.

  2. Simple and efficient purification of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Dettlaff-Weglikowska, U.; Roth, S.

    2001-11-01

    Single-walled carbon nanotubes (SWNTs) produced by arc-discharge and laser ablation were purified by selective oxidation in air at 350°C and subsequent HCl treatment at 120°C. Raw soot and purified samples were analyzed with X-ray diffraction, thermogravimetric analysis (TGA), chemical analysis and transmission electron microscopy (TEM). The optimized purification temperature of SWNTs in air, 350°C, has been determined from TGA curves. Repetition of the oxidation and acid treatment, larger than 95 wt.% purity of SWNTs has been obtained.

  3. The abundance and stability of “water” in type 1 and 2 carbonaceous chondrites (CI, CM and CR)

    NASA Astrophysics Data System (ADS)

    Garenne, A.; Beck, P.; Montes-Hernandez, G.; Chiriac, R.; Toche, F.; Quirico, E.; Bonal, L.; Schmitt, B.

    2014-07-01

    Carbonaceous chondrites record processes of aqueous alteration in the presence of hydrated and hydroxylated minerals, which could have provided a source of water in the inner solar system (Alexander et al., 2012, 2013). In this study, thermogravimetric analysis (TGA) was performed on 26 CM chondrites, which cover a range of degree of aqueous alteration from 2.0, such as Meteorite Hills (MET) 01070, to 2.6, such as Queen Alexandra Range (QUE) 97990, in order to quantify their water content. In addition, by measuring the release of volatile elements as a function of temperature, we obtained information on the mineralogy of water-bearing phases and provide indicators of aqueous alteration based on water released by phyllosilicates. These analyses are combined with infrared spectroscopy (IR) made on meteorite pellets heated up to 300 °C. The infrared features (-OH band at 3-μm and SiO4 around 10-μm) revealed a correlation with TGA. The two techniques are in agreement with the scheme of aqueous alteration proposed by Rubin et al. (2007) and Alexander et al. (2013) based on phyllosilicate abundance. The low temperature (200-400 °C) mass loss observed in TGA is attributed to Fe-oxy-hydroxydes (ferrihydrite, goethite). However, the proportion of these minerals formed by terrestrial alteration remains unknown. TGA also revealed two anomalous CM chondrites, Pecora Escarpment (PCA) 02012 and PCA 02010. Their TGA curves are significantly different from those of “regular” CMs with little mass loss, which can be related to the dehydration history of these meteorites in response to a heating event (Raman measurements also point toward a thermal event, Quirico et al., 2013). In the case of more mildly heated chondrites, such as with Wisconsin Range (WIS) 91600, the TGA curve presents similar mass loss to the other CMs. Seven bulk measurements of CR chondrites and 3 measurements of matrix-enriched parts of CR meteorites were also studied by TGA, and confirm the low

  4. Synthesis of Soluble Halogenated Polyphenylenes. Mechanism for the Coupling Halogenated Lithiobenzenes

    DTIC Science & Technology

    1993-11-22

    the halogen content in these polymers was lowered using larger amounts of tert- butyllithium. TGA analysis (N2 , 20C/rmin) of I1 showed a 10% weight...iodide for every three aryl rings. DSC analysis (N2 , 20°C/min) for 1 8 showed no transitions on either the first or second heating scans to 230"C. TGA ... analysis (N2. 20C/rmin) showed a 10% weight loss at 3220C and char yields of 46% at 900"C. Visual analysis of the charred material did indicate that

  5. Preparation and characterization of poly(vinyl alcohol)/graphene nanofibers synthesized by electrospinning

    NASA Astrophysics Data System (ADS)

    Barzegar, Farshad; Bello, Abdulhakeem; Fabiane, Mopeli; Khamlich, Saleh; Momodu, Damilola; Taghizadeh, Fatemeh; Dangbegnon, Julien; Manyala, Ncholu

    2015-02-01

    We report on the synthesis and characterization of electrospun polyvinyl alcohol (PVA)/graphene nanofibers. The samples produced were characterized by Raman spectroscopy for structural and defect density analysis, scanning electron microscopy (SEM) for morphological analysis, and thermogravimetric (TGA) for thermal analysis. SEM measurements show uniform hollow PVA fibers formation and excellent graphene dispersion within the fibers, while TGA measurements show the improved thermal stability of PVA in the presence of graphene. The synthesized polymer reinforced nanofibers have potential to serve in many different applications such as thermal management, supercapacitor electrodes and biomedical materials for drug delivery.

  6. Fabrication and Characterization of Multi-Walled Carbon Nanotube (MWCNT) and Ni-Coated Multi-Walled Carbon Nanotube (Ni-MWCNT) Repair Patches for Carbon Fiber Reinforced Composite Systems

    NASA Technical Reports Server (NTRS)

    Johnson, Brienne; Caraccio, Anne; Tate, LaNetra; Jackson, Dionne

    2011-01-01

    Multi-walled carbon nanotube (MWCNT)/epoxy and nickel-coated multi-walled carbon nanotube (Ni-MWCNT)/epoxy systems were fabricated into carbon fiber composite repair patches via vacuum resin infusion. Two 4 ply patches were manufactured with fiber orientations of [90/ 90/ 4590] and [0/90/ +45/ -45]. Prior to resin infusion, the MWCNT/Epoxy system and NiMWCNT/ epoxy systems were optimized for dispersion quality. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to determine the presence ofcarbon nanotubes and assess dispersion quality. Decomposition temperatures were determined via thermogravametric analysis (TGA). SEM and TGA were also used to evaluate the composite repair patches.

  7. Kinetic Study on Pyrolysis of Oil Palm Frond

    NASA Astrophysics Data System (ADS)

    Soon, V. S. Y.; Chin, B. L. F.; Lim, A. C. R.

    2016-03-01

    The pyrolysis of oil palm frond is studied using thermogravimetric analysis (TGA) equipment. The present study investigates the thermal degradation behaviour and determination of the kinetic parameters such as the activation energy (EA ) and pre-exponential factor (A) values of oil palm frond under pyrolysis condition. The kinetic data is produced based on first order rate of reaction. In this study, the experiments are conducted at different heating rates of 10, 20, 30, 40 and 50 K/min in the temperature range of 323-1173 K under non-isothermal condition. Argon gas is used as an inert gas to remove any entrapment of gases in the TGA equipment.

  8. [Emission of volatile sulfur gases from Chinese paddy soils].

    PubMed

    Qiao, W; Yang, Z; Cao, J; Li, Z

    2001-09-01

    In the paper, emission of volatile sulfur gases from paddy soil was discussed in a growth period of paddy rice by constructing a field sampling system. The result showed that COS, CS2, DMS and DMDS were mainly emitted from paddy soil. The order of emission fluxes was 81.11, 6.33 and 10.71 mg.(m2.a)-1. Sulphur emission fluxes of Chinese paddy soil was 0.013662 Tg/a, and those of world paddy soil was 0.07992 Tg/a.

  9. Experimental oxygen potentials for U1-yPryO2±x and thermodynamic assessment of the U-Pr-O system

    NASA Astrophysics Data System (ADS)

    McMurray, J. W.; Silva, C. M.

    2016-03-01

    Thermogravimetric analysis (TGA) was used to determine the oxygen potentials of fluorite urania-praseodymia (U1-yPryO2±x) solid solutions for y = 0.10 and 0.20 between 1000 and 1500 °C. A thermodynamic assessment of U-Pr-O system was performed using the CALPHAD (CALculation of PHAse Diagrams) method. The models well reproduce the TGA measurements and the computed phase relations are in good agreement with those proposed from an X-ray diffraction investigation.

  10. Dynamic Moisture Sorption and Desorption in Fumed Silica-filled Silicone Foam

    SciTech Connect

    Trautschold, Olivia Carol

    2016-09-02

    Characterizing dynamic moisture sorption and desorption in fumed silica-filled silicone foam is necessary for determining material compatibilities and life predictions, particularly in sealed environments that may be exposed to a range of environmental conditions. Thermogravimetric analysis (TGA) and near infrared spectroscopy (NIR) were performed on S5470 fumed silica-filled silicone foam to determine the weight percent of moisture at saturation. Additionally, TGA was used to determine the time, temperature, and relative humidity levels required for sorption and desorption of physisorbed moisture in S5470.

  11. Functional changes in the uterine artery precede the hypertensive phenotype in a transgenic model of hypertensive pregnancy

    PubMed Central

    Yamaleyeva, Liliya M.; Varagic, Jasmina; McGee, Carolynne; Bader, Michael; Dechend, Ralf; Brosnihan, K. Bridget

    2015-01-01

    The pregnant female human angiotensinogen (hAGN) transgenic rat mated with the male human renin (hREN) transgenic rat is a model of preeclampsia (TgA) with increased blood pressure, proteinuria, and placenta alterations of edema and necrosis at late gestation. We studied vascular responses and the role of COX-derived prostanoids in the uterine artery (UA) at early gestation in this model. TgA UA showed lower stretch response, similar smooth muscle α-actin content, and lower collagen content compared with Sprague-Dawley (SD) UA. Vasodilation to acetylcholine was similar in SD and TgA UA (64 ± 8 vs. 75 ± 6% of relaxation, P > 0.05), with an acetylcholine-induced contraction in TgA UA that was abolished by preincubation with indomethacin (78 ± 6 vs. 83 ± 11%, P > 0.05). No differences in the contraction to phenylephrine were observed (159 ± 11 vs. 134 ± 12 %KMAX, P > 0.05), although in TgA UA this response was greatly affected by preincubation with indomethacin (179 ± 16 vs. 134 ± 9 %KMAX, P < 0.05, pD2 5.92 ± 0.08 vs. 5.85 ± 0.03, P < 0.05). Endothelium-independent vasodilation was lower in TgA UA (92 ± 2 vs. 74 ± 5% preconstricted tone, P < 0.05), and preincubation with indomethacin restored the response to normal values (90 ± 3 vs. 84 ± 3%). Immunostaining showed similar signals for α-actin, COX-2, and eNOS between groups (P > 0.05). Plasma thromboxane levels were similar between groups. In summary, TgA UA displays functional alterations at early gestation before the preeclamptic phenotype is established. Inhibition of COX enzymes normalizes some of the functional defects in the TgA UA. An increased role for COX-derived prostanoids in this model of preeclampsia may contribute to the development of a hypertensive pregnancy. PMID:26394667

  12. Experimental oxygen potentials of U1-yPryO2± x and thermodynamic assessment of the U-Pr-O system

    DOE PAGES

    McMurray, Jake W.; Silva, Chinthaka M.

    2015-12-09

    Thermogravimetric analysis (TGA) was used to determine the oxygen potentials of fluorite urania-praseodymia (U1-yPryO2± x) solid solutions for y = 0.10 and 0.20 between 1000 and 1500 °C. A thermodynamic assessment of U-Pr-O system was performed using the CALPHAD (CALculation of PHAse Diagrams) method. Furthermore, the models well reproduce the TGA measurements and the computed phase relations are in good agreement with those proposed from an X-ray diffraction investigation.

  13. Mössbauer studies of solid state decomposition of methyl methacrylate-ethyl methacrylate copolymers containing ferric chloride

    NASA Astrophysics Data System (ADS)

    Kapur, G. S.; Brar, A. S.

    1990-07-01

    Methyl methacrylate (MMA)-ethyl methacrylate (EMA) copolymers of different monomer concentrations containing anhydrous ferric chloride were prepared by bulk polymerization at 70°C. TGA studies showed that inclusion of iron salt increases the thermal stability of copolymers by 50°C. Mössbauer spectra of copolymers heated at different temperatures showed the presence of Fe3+ species only, in different environments. The mechanism of thermal stabilization of copolymer has been proposed on the basis of IR, TGA and Mössbauer spectroscopy studies.

  14. Generation of drugs coated iron nanoparticles through high energy ball milling

    NASA Astrophysics Data System (ADS)

    Radhika Devi, A.; Chelvane, J. A.; Prabhakar, P. K.; Padma Priya, P. V.; Doble, Mukesh; Murty, B. S.

    2014-03-01

    The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells.

  15. Generation of drugs coated iron nanoparticles through high energy ball milling

    SciTech Connect

    Radhika Devi, A.; Murty, B. S.; Chelvane, J. A.; Prabhakar, P. K.; Padma Priya, P. V.; Doble, Mukesh

    2014-03-28

    The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells.

  16. Teaching Instrumentation Concepts by the Examination of Thermal Properties of Elastomers

    NASA Astrophysics Data System (ADS)

    Vierheller, Timothy

    2012-04-01

    Fundamental instrumentation concepts were taught using two important thermal techniques in characterizing elastomeric materials: Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA). Instrumentation concepts included the following: calibration, resolution, accuracy, and precision. Basic thermal properties (such as specific heat capacity, glass transition temperature, melting temperature, melting enthalpy, and decomposition temperature) of elastomeric materials were reviewed, as was how DSC and TGA measure these properties. Using this background, instrumentation concepts were examined using collected data and related statistical information. Materials examined included polyethylene, nitrile rubber, and a natural rubber-butadiene blend.

  17. Intumescent Reaction Mechanisms: An Analytic Model.

    DTIC Science & Technology

    1983-05-01

    or amide (such as urea, melamine , dicyan- diamide, urea formaldehyde , etc.) is the release of nonflammable gases (CO2, E . etc.) that physically...mo)/dT Versus I/T (Polysulfide) 34 5-3 Fourier Series Representation of TGA Data for Polysulfide, DIP-30, EPON Resin , and Borax 40 5-4 Fourier Series...Representation of TGA Data for Part A, Part B, and Part A+B 41 5-S Fourier Series Representation of d(m/m )/dT for Polysul- fide, DIP-30, EPOI Resin

  18. Acrylonitrile butadiene rubber (NBR)/manganous tungstate (MnWO4) nanocomposites: Characterization, mechanical and electrical properties

    NASA Astrophysics Data System (ADS)

    Ramesan, M. T.; Abdu Raheem V., P.; Jayakrishnan, P.; Pradyumnan, P. P.

    2014-10-01

    Nanocomposites of NBR with manganous-tungstate nanoparticles were prepared through vulcanization process. The extent of interaction of nanoparticles with the polymer was studied by FTIR, SEM, XRD, TGA and AC conductivity. FTIR and XRD ascertain the interaction of NBR with MnWO4 nanoparticles. SEM analysis established that the nanopartilces were well dispersed in the macromolecular chain of NBR. The mechanical properties of the nanocomposites were studied as a function of filler loading. The nanocomposites exhibited enhanced thermal stability as seen in TGA. Conductivity and dielectric properties of nanocomposites increase with increase in concentration of MnWO4 nanoparticles (7phr) and thereafter the value decreases.

  19. Pulmonary Interstitial Glycogenosis: A Reversible Underlying Condition Associated With D-Transposition of the Great Arteries and Severe Persistent Pulmonary Hypertension.

    PubMed

    Sanchez-de-Toledo, Joan; González-Peris, Sebastià; Gran, Ferran; Gregoraci, Angela; Ferreres, Joan Carles; Ruiz, Cèsar W; Balcells, Joan; Abella, Raul F

    2015-07-01

    Transposition of the great arteries with intact ventricular septum and persistent pulmonary hypertension (TGA-IVS PPHN) is a rare association with a poor prognosis. We report the case of a term newborn with TGA-IVS PPHN successfully managed with perioperative extracorporeal membrane oxygenation (ECMO) and aggressive pulmonary vasodilation therapy that underwent successful arterial switch procedure. A lung biopsy obtained during the surgical procedure showed pulmonary interstitial glycogenosis, a reversible condition. Concerns over left ventricle deconditioning after ECMO could be minimized with appropriate management and monitoring of the ductus arteriosus and appropriate timing of surgery.

  20. Experimental oxygen potentials of U1-yPryO2± x and thermodynamic assessment of the U-Pr-O system

    SciTech Connect

    McMurray, Jake W.; Silva, Chinthaka M.

    2015-12-09

    Thermogravimetric analysis (TGA) was used to determine the oxygen potentials of fluorite urania-praseodymia (U1-yPryO2± x) solid solutions for y = 0.10 and 0.20 between 1000 and 1500 °C. A thermodynamic assessment of U-Pr-O system was performed using the CALPHAD (CALculation of PHAse Diagrams) method. Furthermore, the models well reproduce the TGA measurements and the computed phase relations are in good agreement with those proposed from an X-ray diffraction investigation.

  1. VERUCLAY – a new type of photo-adsorbent active in the visible light range: modification of montmorillonite surface with organic surfactant

    EPA Science Inventory

    Montmorillonite K10 was treated with VeruSOL-3, a biodegradable and food-grade surfactant mixture of coconut oil, castor oil and citrus extracts, to manufacture a benign catalytic adsorbent that is active in the visible light. Veruclay was characterized by SEM, XRD, TGA, UVDRS, a...

  2. Neuropsychological and Psychiatric Outcomes in Dextro-Transposition of the Great Arteries across the Lifespan: A State-of-the-Art Review.

    PubMed

    Kasmi, Leila; Bonnet, Damien; Montreuil, Michèle; Kalfa, David; Geronikola, Nikoletta; Bellinger, David C; Calderon, Johanna

    2017-01-01

    Advances in prenatal diagnosis, perioperative management, and postoperative care have dramatically increased the population of survivors of neonatal and infant heart surgery. The high survival rate of these patients into adulthood has exposed the alarming prevalence of long-term neuropsychological and psychiatric morbidities. Dextro-transposition of the great arteries (d-TGA) is one of the most extensively studied cyanotic congenital heart defect (CHD) with regard to neurodevelopmental outcomes. Landmark studies have described a common neurodevelopmental and behavioral phenotype associated with d-TGA. Children with d-TGA display impairments in key neurocognitive areas, including visual-spatial and fine motor abilities, executive functioning, processing speed, and social cognition. As they grow older, they may face additional challenges with a worsening of deficits in higher order cognitive skills, problems in psychosocial adjustment and a higher-than-expected rate of psychiatric disorders, such as attention-deficit hyperactivity disorder, depression, and anxiety. The aim of this review is to summarize the available recent data on neuropsychological and psychiatric outcomes in individuals with d-TGA after the arterial switch operation. We present findings within a life-span perspective, with a particular emphasis on the emerging literature on adolescent and young adult outcomes. Finally, we propose avenues for future research in the CHD adult neuropsychology field. Among these avenues, we explore the potential mechanisms by which pediatric neurodevelopmental impairments may have lifelong adverse effects as well as alternative interventions that could optimize outcomes.

  3. Limited thermal stability of imidazolium and pyrrolidinium ionic liquids

    SciTech Connect

    Del Sesto, Rico E; Mccleskey, T; Macomber, Clay; Ott, Kevin; Koppisch, Andrew; Baker, Gary A; Burrell, Anthony K

    2009-01-01

    Ionic liquids, with their vast applications, have been touted as being thermally stable to very high temperatures. However, decomposition not detected by standard TGA and NMR techniques are observed with spectroscopic techniques sensitive enough to see small amounts of impurities. Decomposition temperatures of common ionic liquids appear to occur at hundreds of degrees below those temperatures previously reported.

  4. Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water.

    EPA Science Inventory

    Hybrid TiO2/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl4. The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV–vis DRS and TGA. Surfac...

  5. Quantification of H2O and CO2 in Primitive Meteorites and Relation with NIR/MIR Spectra

    NASA Astrophysics Data System (ADS)

    Beck, P.; Garenne, A.; Grisolle, F.; Montes-Hernandez, G.; Bonal, L.; Chiriac, R.; Toche, F.; Quirico, E.; Moynier, F.; Schmitt, B.

    2012-05-01

    We study the NIR/MIR spectra of hydrated meteorites, discuss the water related signatures, which we relate to the quantification of H2O and CO2 made by TGA. We also compare with signatures at 3 microns detected on asteroids.

  6. A detailed study on the thermal endurance of Kapton HNTM and Upilex STM

    NASA Astrophysics Data System (ADS)

    Heltzel, S.; Semprimoschnig, C. O. A.

    2003-09-01

    Assessing the thermal endurance by isothermal testing in a Thermogravimetric Analyser (TGA) is a time consuming method. A quicker method is to perform kinetic modelling on several decomposition curves. Four temperature scans at different heating rates were recorded with the TGA for two thermal control foils, Kapton HN and Upilex S. Two methods of kinetic modelling were used to calculate the activation energy, i.e. the ASTM E 1641 and the approach of Model Free Kinetics (MFK). The first assumes a constant value for the activation energy whereas the latter calculates it as a function of the conversion. With the activation energy it is possible to make a lifetime prediction that indicates the mass loss that occurs at a certain temperature for a certain duration. The lifetime predictions are used to compare the two materials and also the two modelling methods. The modelling is verified by comparing the results to isothermal TGA tests and thermal ageing of samples in high vacuum chambers at 350°C for durations up to half a year and in combination with UV irradiation screening tests. All the performed experiments indicate that Upilex S has a better thermal endurance than Kapton HN. The results of the kinetic modelling are in good agreement with the isothermal experiments in the TGA and in the vacuum facilities. The MFK approach for kinetic modelling was found to be more adequate than the ASTM method.

  7. Thermal Analysis of Self-Propagating Reaction Joining Material

    DTIC Science & Technology

    1999-03-01

    stainless steel instruments. The powders were also mixed for 10 min just prior to thermal SHS reaction. 2.2. Thermal Analysis. Simultaneous DTA/ TGA ... analysis was performed using a TA Instruments model 2960, capable of reaching a maximum temperature of 1,500° C. Two series of experiments were

  8. Determining Water Content of Geologic Materials Using Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Milliken, R. E.; Mustard, J. F.

    2004-03-01

    TGA data and reflectance spectra are used to track changes in water absorptions as a function of absolute water content. Calculating band depth areas of absorptions in VIS-NIR data may prove useful for quantifying the water content of Mars' surface.

  9. Study on structure and thermal stability properties of lignin during thermostabilization and carbonization.

    PubMed

    Li, Yamin; Cui, Dongxu; Tong, Yuanjian; Xu, Lianghua

    2013-11-01

    Soda lignin was first thermostabilized prior to carbonization. The composition, structures and thermal properties of treated lignin were investigated by EA, TGA-MS, (13)C NMR, TGA, and Raman. EA and TGA-MS results showed that the hydrogen content decreased continuously and the oxygen content increased up to 260 °C then decreased and the carbon content increased passively during thermostabilization. (13)C NMR results revealed that thermostabilization could be divided into three stages according to the evolution of the oxygenated structures content: <260 °C, 260-290 °C, >290 °C. Raman analysis showed that R values at each carbonization temperature were concave-down and non-symmetrical parabolic type and the 260 °C thermostabilized lignin after 1400 °C carbonized obtained the minimum R value 1.84. TGA results indicated that overall yields reflecting thermal stability of the thermostabilized samples, especially thermostabilized at 260-290 °C, were higher than that of untreated lignin.

  10. Catalytic thermal cracking of post-consumer waste plastics to fuels: Part 1 - Kinetics and optimization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermogravimetric analysis (TGA) was used to investigate thermal and catalytic pyrolysis of waste plastics such as prescription bottles (polypropylene/PP), high density polyethylene, landfill liners (polyethylene/PE), packing materials (polystyrene/PS), and foams (polyurethane/PU) into crude plastic...

  11. Catalytic and thermal depolymerization of low value post-consumer high density polyethylene plastic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The feasibility of catalytic and non-catalytic pyrolytic conversion of low value post-consumer high density polyethylene (HDPE) plastic into crude oil and subsequent distillation was explored. Translation of optimized conditions for catalytic and non-catalytic pyrolysis from TGA to a bench-scale sys...

  12. Thermal Analysis of Plastics

    ERIC Educational Resources Information Center

    D'Amico, Teresa; Donahue, Craig J.; Rais, Elizabeth A.

    2008-01-01

    This lab experiment illustrates the use of differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) in the measurement of polymer properties. A total of seven exercises are described. These are dry exercises: students interpret previously recorded scans. They do not perform the experiments. DSC was used to determine the…

  13. Hantavirus Pulmonary Syndrome in Central Bolivia: Relationships Between Reservoir Hosts, Habitats, and Viral Genotypes

    DTIC Science & Technology

    2005-01-01

    GAT GA-3 Anti-sense PPT716R 5-AAI CCI ATI ACI CCC AT-3 Rodent cytochrome b primers L1472419 5-CGA AGC TTG ATA TGA AAA ACC ATC GTT G-3 L1464821...Lee HW, 1996. Serological evidence of human hantavirus infection in Argentina, Bolivia and Uruguay. Medicina (B Aires) 56: 17–22. 6. Johnson AM, de

  14. Comparative biophysical properties of tenofovir-loaded, thiolated and nonthiolated chitosan nanoparticles intended for HIV prevention

    PubMed Central

    Meng, Jianing; Zhang, Tao; Agrahari, Vivek; Ezoulin, Miezan J; Youan, Bi-Botti C

    2014-01-01

    Aim This study is designed to test the hypothesis that tenofovir-loaded (an anti-HIV microbicide) chitosan–thioglycolic acid-conjugated (CS–TGA) nanoparticles (NPs) exhibit superior biophysical properties for mucoadhesion compared with those of native CS NPs. Materials & methods The NPs are prepared by ionotropic gelation. The particle mean diameter, encapsulation efficiency and release profile are analyzed by dynamic light scattering and UV spectroscopy, respectively. The cytotoxicity, cellular uptake and uptake mechanism are assessed on VK2/E6E7 and End1/E6E7 cell lines by colorimetry/fluorimetry, and percentage mucoadhesion is assessed using porcine vaginal tissue. Results The mean diameter of the optimal NP formulations ranges from 240 to 252 nm, with a maximal encapsulation efficiency of 22.60%. Tenofovir release from CS and CS–TGA NPs follows first-order and Higuchi models, respectively. Both NPs are noncytotoxic in 48 h. The cellular uptake, which is time dependent, mainly occurs via the caveolin-mediated pathway. The percentage of mucoadhesion of CS–TGA NPs is fivefold higher than that of CS NPs, and reached up to 65% after 2 h. Conclusion Collectively, CS–TGA NPs exhibit superior biophysical properties and can potentially maximize the retention time of a topical microbicide, such as tenofovir, intended for the prevention of HIV transmission. PMID:24405490

  15. Potato glycoalkaloids and adverse effects in humans: an ascending dose study.

    PubMed

    Mensinga, Tjeert T; Sips, Adrienne J A M; Rompelberg, Cathy J M; van Twillert, Klaas; Meulenbelt, Jan; van den Top, Hester J; van Egmond, Hans P

    2005-02-01

    Glycoalkaloids in potatoes may induce gastro-intestinal and systemic effects, by cell membrane disruption and acetylcholinesterase inhibition, respectively. The present single dose study was designed to evaluate the toxicity and pharmacokinetics of orally administered potato glycoalkaloids (alpha-chaconine and alpha-solanine). It is the first published human volunteer study were pharmacokinetic data were obtained for more than 24 h post-dose. Subjects (2-3 per treatment) received one of the following six treatments: (1-3) solutions with total glycoalkaloid (TGA) doses of 0.30, 0.50 or 0.70 mg/kg body weight (BW), or (4-6) mashed potatoes with TGA doses of 0.95, 1.10 or 1.25 mg/kg BW. The mashed potatoes had a TGA concentration of nearly 200 mg/kg fresh weight (the presently recognised upper limit of safety). None of these treatments induced acute systemic effects. One subject who received the highest dose of TGA (1.25 mg/kg BW) became nauseous and started vomiting about 4 h post-dose, possibly due to local glycoalkaloid toxicity (although the dosis is lower than generally reported in the literature to cause gastro-intestinal disturbances). Most relevant, the clearance of glycoalkaloids usually takes more than 24 h, which implicates that the toxicants may accumulate in case of daily consumption.

  16. Characterization and Transcriptional Profile of Genes Involved in Glycoalkaloid Biosynthesis in New Varieties of Solanum tuberosum L.

    PubMed

    Mariot, Roberta Fogliatto; de Oliveira, Luisa Abruzzi; Voorhuijzen, Marleen M; Staats, Martijn; Hutten, Ronald C B; van Dijk, Jeroen P; Kok, Esther J; Frazzon, Jeverson

    2016-02-03

    Before commercial release, new potato (Solanum tuberosum) varieties must be evaluated for content of toxic compounds such as glycoalkaloids (GAs), which are potent poisons. GA biosynthesis proceeds via the cholesterol pathway to α-chaconine and α-solanine. The goal of this study was to evaluate the relationship between total glycoalkaloid (TGA) content and the expression of GAME, SGT1, and SGT3 genes in potato tubers. TGA content was measured by HPLC-MS, and reverse transcription quantitative polymerase chain reactions were performed to determine the relative expression of GAME, SGT1, and SGT3 genes. We searched for cis-elements of the transcription start site using the PlantPAN database. There was a relationship between TGA content and the relative expression of GAME, SGT1, and SGT3 genes in potato tubers. Putative promoter regions showed the presence of several cis-elements related to biotic and abiotic stresses and light. These findings provide an important step toward understanding TGA regulation and variation in potato tubers.

  17. Maternal-infant interaction and autonomic function in healthy infants and infants with transposition of the great arteries.

    PubMed

    Harrison, Tondi M; Ferree, Allison

    2014-12-01

    The quality of maternal-infant interaction is a critical factor in the development of infants' autonomic function and social engagement skills. In this secondary data analysis, relationships among infant and maternal affect and behavior and quality of dyadic interaction, as measured by the Parent-Child Early Relational Assessment, and infant autonomic function, as measured by heart rate variability, were examined during feeding at 2 weeks and 2 months of age in 16 healthy infants and in 15 infants with transposition of the great arteries (TGA). Contrary to previous research, at 2 weeks infant age, mothers of infants with TGA had significantly higher scores in affect and behavior than did mothers of healthy infants. The affect and behavior and quality of dyadic interaction of infants with TGA also did not differ from that of healthy infants. Although infants' social engagement skills did not differ by health condition (TGA or healthy), these skills did differ by parasympathetic nervous system function: infants better able to suppress vagal activity with challenge had more positive and less dysregulated affect and behavior, regardless of health status. These findings suggest that maternal-infant interactions for some cardiac disease subgroups may not differ from healthy dyads. Additional research is required to identify both healthy and ill infants with delayed autonomic maturation and to develop and test interventions to enhance critical interactive functions.

  18. pMDI-Reinforced Compression-Molded PCL/Gluten: Thermomechanical Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polycaprolactone (PCL) and vital wheat gluten or wheat flour composites were prepared and compatibilized with polymeric diphenylmethane diisocyanate (pMDI) by blending and compression-molding. The thermo-mechanical properties of the composites were determined by thermogravimetric analysis (TGA), di...

  19. Thermal and mechanical properties of compression-molded pMDI-reinforced PCL/gluten composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polycaprolactone (PCL) and vital wheat gluten or wheat flour composites were prepared and compatibilized with polymeric diphenylmethane diisocyanate (pMDI) by blending and compression-molding. The thermo-mechanical properties of the composites were determined by thermogravimetric analysis (TGA), di...

  20. Vascular Ischemia as a Cause of Transient Global Amnesia: A Patient Series

    PubMed Central

    GÜNGÖR TUNÇER, Özlem; AKSAY KOYUNCU, Bahar; VİLDAN OKUDAN, Zeynep; ALTINDAĞ, Ebru; TOLUN, Reha; KRESPİ, Yakup

    2015-01-01

    Introduction Epileptic, migrainous, and vascular pathologies may cause transient global amnesia (TGA); however, the mechanism of causation remains unclear. We investigated possible vascular causes of TGA. Methods We retrospectively evaluated the clinical and radiologic studies of 13 patients with TGA. On admission, patients underwent diffusion-weighted imaging (DWI) and intra- and extracranial magnetic resonance angiography (MRA); vascular risk factor profiles for diabetes, hypertension, and hyperlipidemia; electroencephalography; and neuropsychological tests. Seven patients underwent control DWIs 24 h after symptom onset. Results One patient had two punctiform acute infarcts in the left hippocampus, and one had a left pontine paramedian acute infarct. In the second patient, control DWI showed additional left hippocampal and right frontal acute infarcts. None of the patients had electroencephalographic evidence of epileptic activity. All patients except for one had at least one vascular risk factor. The second patient was shown to have paroxsysmal atrial fibrillation during follow-up. Conclusion Minor posterior circulation ischemic stroke appears to cause TGA in some patients. Evaluations such as DWI and vascular risk factor assessment may be helpful in making the diagnosis.

  1. Microparticle dispensers for the controlled release of insect pheromones.

    PubMed

    Stipanovic, Arthur J; Hennessy, Patrick J; Webster, Francis X; Takahashi, Yae

    2004-04-21

    The potential utility of micrometer-sized particles as controlled-release devices for the volatilization of insect pheromones for mating disruption applications is evaluated in this study for two pheromone/model compound systems (codlemone/1-dodecanol and disparlure/1,2-epoxyoctadecane). To expedite the measurement of release rates from these particle devices, two techniques based on thermogravimetric analysis (TGA) have been exploited: isothermal TGA (I-TGA) at elevated temperatures (40-80 degrees C) with N(2) convection and volatilization temperature (VT) by dynamic TGA. A correlation between these two methods has been established. Samples that exhibit a higher VT provide a lower release rate from a particle substrate. Using these techniques, it has been demonstrated that chemical interactions between adsorbed liquids and particle surfaces may play a small role in defining release characteristics under conditions of low surface area, whereas parameters associated with total surface area and micropore structure appear to be much more significant in retarding evaporation for uncoated particles containing an adsorbed liquid. Additional regulation of release rates was achieved by coating the particle systems with water-soluble or water-dispersible polymers. By careful selection of particle porosity and coating composition, it is envisioned that the evaporation rate of pheromones can be tailored to specific insect control applications.

  2. Screening of the chemical reactivity of three different graphite sources using the formation of reductively alkylated graphene as a model reaction.

    PubMed

    Knirsch, Kathrin C; Englert, Jan M; Dotzer, Christoph; Hauke, Frank; Hirsch, Andreas

    2013-11-28

    Reductive alkylation of three graphite starting materials G(flake), G(powder), and G(spherical) reveals pronounced differences in the obtained covalently functionalized graphene with respect to the degree of functionalization, exfoliation efficiency and product homogeneity, as demonstrated by statistical Raman microscopy (SRM), TGA/MS, IR-spectroscopy and solubility behavior.

  3. Sol-gel synthesis and properties of phosphate ceramics

    SciTech Connect

    Lee, Burtrand I.; Cao, Zhicheng; Samuels, William D.; Exarhos, Gregory J.

    2000-09-01

    Silicon, titanium, zirconium phosphates were synthesized by starting with appropriate chemical precursors in a solution. The synthetic procedure, chemical and physical structures were examined by FT-IR, liquid and solid state NMR, TGA, SEM, XRD, etc. The phosphates were examined for thermal and electrical properties. Advantages of the synthesis technique and the data on unique structures and thermal properties are reported.

  4. Pre-Concentration for Improved Long-Term Monitoring of Contaminants in Groundwater

    DTIC Science & Technology

    2009-01-01

    extraction SPME solid phase microextraction TEM Transmission electron microscopy TGA Thermogravimetric analysis TMB mesitylene; 1,3,5-Trimethylbenzene...in extraction processes, time-consuming steps, and necessary conditioning processes. Solid-phase microextraction (SPME) fibers provide a method of... microextraction /gas chromatography-electron capture detection for the determination of energetic chemicals, in marine samples. Journal of

  5. Noninvasive Assessment of Vascular Function in Postoperative Cardiovascular Disease (Coarctation of the Aorta, Tetralogy of Fallot, and Transposition of the Great Arteries).

    PubMed

    Mivelaz, Yvan; Leung, Mande T; Zadorsky, Mary Terri; De Souza, Astrid M; Potts, James E; Sandor, George G S

    2016-08-15

    Using noninvasive techniques, we sought to assess arterial stiffness, impedance, hydraulic power, and efficiency in children with postoperative tetralogy of Fallot (TOF), coarctation of the aorta (COA), and transposition of the great arteries (TGAs). Results were compared with those of healthy peers. Fifty-five children with repaired congenital heart disease (24 TOFs, 20 COAs, and 11 TGAs) were compared with 55 age-matched control subjects (CTRL). Echocardiographic Doppler imaging and carotid artery applanation tonometry were preformed to measure aortic flow, dimensions, and calculate pulse wave velocity, vascular impedance and arterial stiffness indexes, hydraulic power (mean and total), and hydraulic efficiency (HE) which were calculated using standard fluid dynamics equations. All congenital heart disease subgroups had higher pulse wave velocity than CTRL. Only the COA group had higher characteristic impedance. Mean power was higher in TGA than in CTRL and TOF, and total power was higher in TGA than in CTRL and TOF. Hydraulic efficiency was higher in TOF than in COA and TGA. In conclusion, children with TOF, COA, and TGA have stiffer aortas than CTRL. These changes may be related to intrinsic aortic abnormalities, altered integrity of the aorta due to surgical repair, and/or acquired postsurgery. These patients may be at increased long-term cardiovascular risk, and long-term follow-up is important for monitoring and assessment of efforts to reduce risk.

  6. Synthesis of nanocrystalline molybdenum carbide (Mo{sub 2}C) by solution route

    SciTech Connect

    Patel, Manish Subrahmanyam, J.

    2008-08-04

    Nanocrystalline molybdenum carbide (Mo{sub 2}C) of less than 10 nm size was synthesized by solution route. The process temperature and composition of raw materials were optimized by thermodynamic equilibrium calculation. The raw materials as well as synthesized nanocrystalline molybdenum carbide were characterized by X-ray diffraction (XRD) and thermogravimetric analysis/differential thermal analysis (TGA/DTA)

  7. Chemical method to enhance transungual transport and iontophoresis efficiency.

    PubMed

    Hao, Jinsong; Smith, Kelly A; Li, S Kevin

    2008-06-05

    Transungual transport is hindered by the inherent small effective pore size of the nail even when it is fully hydrated. The objectives of this study were to determine the effects of chemical enhancers thioglycolic acid (TGA), glycolic acid (GA), and urea (UR) on transungual transport and iontophoresis efficiency. In vitro passive and iontophoretic transport experiments of model permeants mannitol (MA), UR, and tetraethylammonium (TEA) ion across the fully hydrated, enhancer-treated and untreated human nail plates were performed in phosphate-buffered saline. The transport experiments consisted of several stages, alternating between passive and anodal iontophoretic transport at 0.1mA. Nail water uptake experiments were conducted to determine the water content of the enhancer-treated nails. The effects of the enhancers on transungual electroosmosis were also evaluated. Nails treated with GA and UR did not show any transport enhancement. Treatment with TGA at 0.5M enhanced passive and iontophoretic transungual transport of MA, UR, and TEA. Increasing the TGA concentration to 1.8M did not further increase TEA iontophoresis efficiency. The effect of TGA on the nail plates was irreversible. The present study shows the possibility of using a chemical enhancer to reduce transport hindrance in the nail plate and thus enhance passive and iontophoretic transungual transport.

  8. Novel Claycunbic to Eliminate Micropollutants and Vibrio fischeri from Water

    EPA Science Inventory

    Montmorillonite clay (K10) was used as a precursor for the synthesis of a catalytic adsorbent, Claycunbic (Bi/Cu-pillared K10), which was characterized by SEM (EDS), TEM, XRD, BET, TGA and XPS analysis. The catalytic adsorption of cationic dye methylene blue (MB), anionic dye met...

  9. Predicting the Impact of Multiwalled Carbon Nanotubes on the Cement Hydration Products and Durability of Cementitious Matrix Using Artificial Neural Network Modeling Technique

    PubMed Central

    Fakhim, Babak; Hassani, Abolfazl; Rashidi, Alimorad; Ghodousi, Parviz

    2013-01-01

    In this study the feasibility of using the artificial neural networks modeling in predicting the effect of MWCNT on amount of cement hydration products and improving the quality of cement hydration products microstructures of cement paste was investigated. To determine the amount of cement hydration products thermogravimetric analysis was used. Two critical parameters of TGA test are PHPloss and CHloss. In order to model the TGA test results, the ANN modeling was performed on these parameters separately. In this study, 60% of data are used for model calibration and the remaining 40% are used for model verification. Based on the highest efficiency coefficient and the lowest root mean square error, the best ANN model was chosen. The results of TGA test implied that the cement hydration is enhanced in the presence of the optimum percentage (0.3 wt%) of MWCNT. Moreover, since the efficiency coefficient of the modeling results of CH and PHP loss in both the calibration and verification stages was more than 0.96, it was concluded that the ANN could be used as an accurate tool for modeling the TGA results. Another finding of this study was that the ANN prediction in higher ages was more precise. PMID:24489487

  10. Air pollution effects on food quality. Final progress report. CAES No. 555-80

    SciTech Connect

    Pell, E.J.

    1980-01-01

    The impact of ozone on the qualitative characteristics of potatoes, alfalfa and soybeans is discussed. The impact on yield, total solids, sugar status and tuber glycoalkaloid (TGA) content was measured. The effects of ozone on the leaves were also noted. Field trials were conducted as well as laboratory experiments. (DC)

  11. Torrefaction of pomaces and nut shells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technical: Apple, grape, olive, and tomato pomaces as well as almond and walnut shells were torrefied at different temperatures and times in a muffle furnace. The fiber content and thermal stability of the raw byproducts were examined using fiber analysis and thermogravimetric analysis (TGA), respec...

  12. Near-infrared-emitting colloidal Ag2S quantum dots exhibiting upconversion luminescence

    NASA Astrophysics Data System (ADS)

    Zhang, Yanyan; Jiang, Danyu; Yang, Wei; Wang, Dandan; Zheng, Huiping; Du, Yuansheng; Li, Xi; Li, Qiang

    2017-02-01

    Ag2S quantum dots (QDs) coated with thioglycolic acid (Ag2S QDs-TGA) have been synthesized in an organic solvent via a stepwise addition of reagents. When excited by a 980 nm laser, the near-infrared-emitting colloidal Ag2S QDs-TGA exhibit upconversion luminescence (UCL). The observed photoluminescence (PL) was attributed to the presence of ligand-modified Ag2S on the QD surfaces. Hence, upon dilution of the solution, the PL intensity initially increased before subsequently decreasing, accompanied by a blue shift in the PL spectra. The PL phenomena can be attributed to the increase in the amount of ligand-modified Ag2S on the QD surfaces upon dilution, which in turn affected the fluorescence resonance energy transfer (FRET) and re-emission of the surface energy level. The relations between the emission intensity of Ag2S QDs-TGA and the excitation power are investigated, and the results confirm that the UCL in Ag2S QDs-TGA can be ascribed to a two-photon-assisted absorption process via a real energy state.

  13. Analysis of Moisture and CO(2) Uptake in Anhydrous CdCl(2) Powders Used for Vapor CdCl(2) Treatment of CdS/CdTe PV Devices

    SciTech Connect

    Mazur, T.; Gessert, T.; Martins, G.; Curtis, C.

    2000-01-01

    Water and CO(2) uptake in CdCl(2) powder precursors was investigated using thermogravimetric analysis/Fourier transform infrared spectroscopy (TGA/FTIR). Exposure of powders under ambient conditions shows that a steady-state hydration level near 9% (by weight) is achieved after brief exposure to room air.

  14. 78 FR 73460 - Airworthiness Directives; the Boeing Company Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-06

    ... driven pump (ADP) turbine gearbox assembly (TGA), which resulted in the release of high energy fragments... striking passengers, or penetrating the wing-to-body fairing and striking ground handling or maintenance... maintenance personnel, causing serious injury. Relevant Service Information We reviewed Boeing...

  15. A major QTL and an SSR marker associated with glycoalkaloid content in potato tubers from Solanum tuberosum x S. sparsipilum located on chromosome I.

    PubMed

    Sørensen, Kirsten Kørup; Kirk, Hanne Grethe; Olsson, Kerstin; Labouriau, Rodrigo; Christiansen, Jørgen

    2008-06-01

    New potato (Solanum tuberosum) varieties are required to contain low levels of the toxic glycoalkaloids and a potential approach to obtain this is through marker-assisted selection (MAS). Before applying MAS it is necessary to map quantitative trait loci (QTLs) for glycoalkaloid content in potato tubers and identify markers that link tightly to this trait. In this study, tubers of a dihaploid BC(1) population, originating from a cross between 90-HAF-01 (S. tuberosum(1)) and 90-HAG-15 (S. tuberosum(2) x S. sparsipilum), were evaluated for content of alpha-solanine and alpha-chaconine (total glycoalkaloid, TGA) after field trials. In addition, tubers were assayed for TGA content after exposure to light. A detailed analysis of segregation patterns indicated that a major QTL is responsible for the TGA content in tubers of this potato population. One highly significant QTL was mapped to chromosome I of the HAG and the HAF parent. Quantitative trait loci for glycoalkaloid production in foliage of different Solanum species have previously been mapped to this chromosome. In the present research, QTLs for alpha-solanine and alpha-chaconine content were mapped to the same location as for TGA content. Similar results were observed for tubers exposed to light. The simple sequence repeat marker STM5136 was closely linked to the identified QTL.

  16. Neuropsychological and Psychiatric Outcomes in Dextro-Transposition of the Great Arteries across the Lifespan: A State-of-the-Art Review

    PubMed Central

    Kasmi, Leila; Bonnet, Damien; Montreuil, Michèle; Kalfa, David; Geronikola, Nikoletta; Bellinger, David C.; Calderon, Johanna

    2017-01-01

    Advances in prenatal diagnosis, perioperative management, and postoperative care have dramatically increased the population of survivors of neonatal and infant heart surgery. The high survival rate of these patients into adulthood has exposed the alarming prevalence of long-term neuropsychological and psychiatric morbidities. Dextro-transposition of the great arteries (d-TGA) is one of the most extensively studied cyanotic congenital heart defect (CHD) with regard to neurodevelopmental outcomes. Landmark studies have described a common neurodevelopmental and behavioral phenotype associated with d-TGA. Children with d-TGA display impairments in key neurocognitive areas, including visual–spatial and fine motor abilities, executive functioning, processing speed, and social cognition. As they grow older, they may face additional challenges with a worsening of deficits in higher order cognitive skills, problems in psychosocial adjustment and a higher-than-expected rate of psychiatric disorders, such as attention-deficit hyperactivity disorder, depression, and anxiety. The aim of this review is to summarize the available recent data on neuropsychological and psychiatric outcomes in individuals with d-TGA after the arterial switch operation. We present findings within a life-span perspective, with a particular emphasis on the emerging literature on adolescent and young adult outcomes. Finally, we propose avenues for future research in the CHD adult neuropsychology field. Among these avenues, we explore the potential mechanisms by which pediatric neurodevelopmental impairments may have lifelong adverse effects as well as alternative interventions that could optimize outcomes. PMID:28393063

  17. Evaluation of Low Hazardous Air Pollutant Thermoset Adhesives for the Application of Rubber-to-Metal Bonding on Army Tank Pads and Road Wheels

    DTIC Science & Technology

    2011-09-01

    and Chemlok 6254-LH thinned with a 50/50 solvent blend of n-butyl propionate and Varnish Makers and Painters (VM&P) naphtha (low-HAP adhesive...data sheet TGA thermogravimetric analysis THF tetrahydrofuran VM&P Varnish Makers and Painters 38 VOC volatile organic compound wt

  18. Fuel Fracture (Crumbling) Safety Impact (OCRWM)

    SciTech Connect

    DUNCAN, D.R.

    1999-12-08

    The safety impact of experimentally observed N Reactor fuel sample fracture and fragmentation is evaluated using an average reaction rate enhancement derived from data from thermo-gravimetric analysis (TGA) experiments on fuel samples. The enhanced reaction rates attributed to fragmentation were within the existing safety basis.

  19. Characterization of blend hydrogels based on plasticized starch/cellulose acetate/carboxymethyl cellulose synthesized by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Senna, Magdy M.; Mostafa, Abo El-Khair B.; Mahdy, Sanna R.; El-Naggar, Abdel Wahab M.

    2016-11-01

    Blend hydrogels based on aqueous solutions of plasticized starch and different ratios of cellulose acetate (CA) and carboxymethyl cellulose (CMC) were prepared by electron beam irradiation (EB). The blends before and after EB irradiation were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The physico-chemical properties of blend hydrogels prepared by electron beam irradiation were improved compared to unirradiated blends.

  20. Thermal, mechanical and morphological characterization of plasticized PLA-PHB blends

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A blend of poly(lactic acid) (PLA) (75% by weight) and poly(3-hydroxybutyrate) (PHB) (25% by weight) with a polyester plasticizer (Lapol 108) at two different concentrations (5 and 7% by weight per 100 parts of the blends) were investigated by TGA, DSC, XRD, SEM, mechanical testing and biodegradatio...

  1. Preparation and thermal behaviour of a series of liquid wood-polypropylene composites

    NASA Astrophysics Data System (ADS)

    Blanco, Ignazio; Cicala, Gianluca; Latteri, Alberta; Saccullo, Giuseppe

    2016-05-01

    Liquid Wood (a mixture of cellulose, hemp, fax and lignin) was used to prepare, by mechanical mixing followed by thermal extrusion, blends of various Polypropylene (PP)/Liquid Wood ratios. To verify if and how much the composition of the obtained composites affects their thermal properties Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) experiments were carried out.

  2. The Synthesis of Transition Metal Nitrides via Thermolysis of Metal-Ammine Complexes: Part 1. Chromium Nitride

    SciTech Connect

    Weil, K. Scott

    2008-01-01

    The thermal decomposition of chromium hexamine chloride in both helium and ammonia gas has been investigated by thermogravimmetric and differential thermal analysis (TGA and DTA) and intermediate reaction products have been examined via Fourier transform infared spectroscopy and powder X-ray diffraction in an effort to understand how ammonolyis of this nitride precursor takes place.

  3. Is It Necessary to Dry Primary Standards before Analysis?

    ERIC Educational Resources Information Center

    Spraggins, Jeffrey M., II; Williams, Theodore R.

    2005-01-01

    The thermal gravimetric analysis (TGA) data suggests that the quantity of volatile components in primary standards is less than 1% of the initial weight and differential scanning calorimetry (DSC) data shows that water present in the same chemicals is below the limit of detection of the instrumentation. This suggests that the 1-2 hour drying…

  4. The effect of extrusion processing on zein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extrusion processing has been carried out on zein where extrusion temperatures were varied between 100 and 300 deg. C. By differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) thermal degradation begins around 220 deg. C. The color of the extrudate changed the most above tempe...

  5. Proximate Analysis of Coal

    ERIC Educational Resources Information Center

    Donahue, Craig J.; Rais, Elizabeth A.

    2009-01-01

    This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

  6. Metallo-Organic Decomposition (MOD) film development

    NASA Technical Reports Server (NTRS)

    Parker, J.

    1986-01-01

    The processing techniques and problems encountered in formulating metallo-organic decomposition (MOD) films used in contracting structures for thin solar cells are described. The use of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques performed at Jet Propulsion Laboratory (JPL) in understanding the decomposition reactions lead to improvements in process procedures. The characteristics of the available MOD films were described in detail.

  7. 32 CFR 231.5 - Procedures-domestic banks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... hospital patients). (v) The name and location of the depositary used to make official deposits for credit to the TGA. (vi) A list of organizational and nonappropriated fund accounts, the name and location of... surveillance equipment, when necessary. (ix) Reasons for use of space controlled by the General...

  8. Implicit Learning in Transient Global Amnesia and the Role of Stress.

    PubMed

    Nees, Frauke; Griebe, Martin; Ebert, Anne; Ruttorf, Michaela; Gerber, Benjamin; Wolf, Oliver T; Schad, Lothar R; Gass, Achim; Szabo, Kristina

    2016-01-01

    Transient global amnesia (TGA) is a disorder with reversible anterograde disturbance of explicit memory, frequently preceded by an emotionally or physically stressful event. By using magnetic resonance imaging (MRI) following an episode of TGA, small hippocampal lesions have been observed. Hence it has been postulated that the disorder is caused by the stress-related transient inhibition of memory formation in the hippocampus. In experimental studies, stress has been shown to affect both explicit and implicit learning-the latter defined as learning and memory processes that lack conscious awareness of the information acquired. To test the hypothesis that impairment of implicit learning in TGA is present and related to stress, we determined the effect of experimental exposure to stress on hippocampal activation patterns during an implicit learning paradigm in patients who suffered a recent TGA and healthy matched control subjects. We used a hippocampus-dependent aversive learning procedure (context conditioning with the phases habituation, acquisition, and extinction) during functional MRI following experimental stress exposure (socially evaluated cold pressor test). After a control procedure, controls showed successful learning during the acquisition phase, indicated by increased valence, arousal and contingency ratings to the paired (CON+) vs. the non-paired (CON-) conditioned stimulus, and successful extinction of the conditioned responses. Following stress, acquisition was still successful, however extinction was impaired with persistently increased contingency ratings. In contrast, TGA patients showed impairment of conditioned responses and insufficient extinction after the control procedure, indicated by a lack of significant differences between CON+ and CON- for valence and arousal ratings after the acquisition phase and by significantly increased contingency ratings after the extinction. After stress, aversive learning was not successful with non

  9. Implicit Learning in Transient Global Amnesia and the Role of Stress

    PubMed Central

    Nees, Frauke; Griebe, Martin; Ebert, Anne; Ruttorf, Michaela; Gerber, Benjamin; Wolf, Oliver T.; Schad, Lothar R.; Gass, Achim; Szabo, Kristina

    2016-01-01

    Transient global amnesia (TGA) is a disorder with reversible anterograde disturbance of explicit memory, frequently preceded by an emotionally or physically stressful event. By using magnetic resonance imaging (MRI) following an episode of TGA, small hippocampal lesions have been observed. Hence it has been postulated that the disorder is caused by the stress-related transient inhibition of memory formation in the hippocampus. In experimental studies, stress has been shown to affect both explicit and implicit learning—the latter defined as learning and memory processes that lack conscious awareness of the information acquired. To test the hypothesis that impairment of implicit learning in TGA is present and related to stress, we determined the effect of experimental exposure to stress on hippocampal activation patterns during an implicit learning paradigm in patients who suffered a recent TGA and healthy matched control subjects. We used a hippocampus-dependent aversive learning procedure (context conditioning with the phases habituation, acquisition, and extinction) during functional MRI following experimental stress exposure (socially evaluated cold pressor test). After a control procedure, controls showed successful learning during the acquisition phase, indicated by increased valence, arousal and contingency ratings to the paired (CON+) vs. the non-paired (CON−) conditioned stimulus, and successful extinction of the conditioned responses. Following stress, acquisition was still successful, however extinction was impaired with persistently increased contingency ratings. In contrast, TGA patients showed impairment of conditioned responses and insufficient extinction after the control procedure, indicated by a lack of significant differences between CON+ and CON− for valence and arousal ratings after the acquisition phase and by significantly increased contingency ratings after the extinction. After stress, aversive learning was not successful with non

  10. Transient Global Amnesia Deteriorates the Network Efficiency of the Theta Band

    PubMed Central

    Yi, SangHak; Lim, Jae-Sung; Jang, Jae-Won; Im, Chang-Hwan; Kim, SangYun

    2016-01-01

    Acute perturbation of the hippocampus, one of the connector hubs in the brain, is a key step in the pathophysiological cascade of transient global amnesia (TGA). We tested the hypothesis that network efficiency, meaning the efficiency of information exchange over a network, is impaired during the acute stage of TGA. Graph theoretical analysis was applied to resting-state EEG data collected from 21 patients with TGA. The EEG data were obtained twice, once during the acute stage (< 24 hours after symptom onset) and once during the resolved stage (> 2 months after symptom onset) of TGA. Characteristic path lengths and clustering coefficients of functional networks constructed using phase-locking values were computed and normalized as a function of the degree in the delta, theta, alpha, beta 1, beta 2 and gamma frequency bands of the EEG. We investigated whether the normalized characteristic path length (nCPL) and normalized clustering coefficients (nCC) differed significantly between the acute and resolved stages of TGA at each frequency band using the Wilcoxon signed-rank test. For networks where the nCPL or nCC differed significantly between the two stages, we also evaluated changes in the connections of the brain networks. During the acute stage of TGA, the nCPL of the theta band networks with mean degrees of 8, 8.5, 9 and 9.5 significantly increased (P < 0.05). During the acute stage, the lost edges for these networks were mostly found between the anterior (frontal and anterior temporal) and posterior (parieto-occipital and posterior temporal) brain regions, whereas newly developed edges were primarily found between the left and right frontotemporal regions. The nCC of the theta band with a mean degree of 5.5 significantly decreased during the acute stage (P < 0.05). Our results indicate that TGA deteriorates the network efficiency of the theta frequency band. This effect might be related to the desynchronization between the anterior and posterior brain areas

  11. Measuring evaporation rates of metal compounds from solid samples.

    PubMed

    Ludwig, Christian; Wochele, Jörg; Jörimann, Urs

    2007-04-01

    A thermogravimeter (TGA, Mettler-Toledo TGA/SDTA851e) was connected to an inductively coupled plasma optical emission spectrometer (ICP-OES, Varian Liberty 110) using a condensation interface (CI), which transforms gaseous high-boiling-temperature substances into solid (or liquid) aerosols. Argon was used as the carrier gas to transfer the aerosols into the ICP-OES for on-line elemental analysis. This new analytical TGA-CI-ICP-OES device, called TGA-ICP, is the first of its kind and allows one to study the thermochemically induced evaporation behavior of high-boiling-temperature substances, such as heavy metal compounds, under different thermochemical conditions. It allows the investigation of the behavior of large solid or liquid samples (100-500 mg), which is important for applying the results to industrial processes. So far, the CI principle has allowed only semiquantitative elemental analyses of hot gases when connected to an ICP-OES. In this work, we show that a direct calibration of the CI-ICP-OES device is possible in combination with a TGA. The intensities determined by ICP-OES could be directly related to gravimetrically determined evaporation rates of volatile model compounds. The results show model evaporation experiments with native CdCl2 and CdCl2 resulting from the reaction of CaCl2 with CdO. Cadmium was studied because it is a volatile toxic heavy metal and its thermal behavior is relevant in various waste-treatment and recycling processes.

  12. Volatile organic compounds in pesticide formulations: Methods to estimate ozone formation potential

    NASA Astrophysics Data System (ADS)

    Zeinali, Mazyar; McConnell, Laura L.; Hapeman, Cathleen J.; Nguyen, Anh; Schmidt, Walter F.; Howard, Cody J.

    2011-05-01

    The environmental fate and toxicity of active ingredients in pesticide formulations has been investigated for many decades, but relatively little research has been conducted on the fate of pesticide co-formulants or inerts. Some co-formulants are volatile organic compounds (VOCs) and can contribute to ground-level ozone pollution. Effective product assessment methods are required to reduce emissions of the most reactive VOCs. Six emulsifiable concentrate pesticide products were characterized for percent VOC by thermogravimetric analysis (TGA) and gas chromatography-mass spectrometry (GC-MS). TGA estimates exceeded GC-MS by 10-50% in all but one product, indicating that for some products a fraction of active ingredient is released during TGA or that VOC contribution was underestimated by GC-MS. VOC profiles were examined using TGA-Fourier transform infrared (FTIR) evolved gas analysis and were compared to GC-MS results. The TGA-FTIR method worked best for products with the simplest and most volatile formulations, but could be developed into an effective product screening tool. An ozone formation potential ( OFP) for each product was calculated using the chemical composition from GC-MS and published maximum incremental reactivity ( MIR) values. OFP values ranged from 0.1 to 3.1 g ozone g -1 product. A 24-h VOC emission simulation was developed for each product assuming a constant emission rate calculated from an equation relating maximum flux rate to vapor pressure. Results indicate 100% VOC loss for some products within a few hours, while other products containing less volatile components will remain in the field for several days after application. An alternate method to calculate a product OFP was investigated utilizing the fraction of the total mass of each chemical emitted at the end of the 24-h simulation. The ideal assessment approach will include: 1) unambiguous chemical composition information; 2) flexible simulation models to estimate emissions under

  13. Evaluating the combustion reactivity of drop tube furnace and thermogravimetric analysis coal chars with a selection of metal additives

    SciTech Connect

    Katherine Le Manquais; Colin E. Snape; Ian McRobbie; Jim Barker

    2011-03-17

    Opportunities exist for effective coal combustion additives that can reduce the carbon content of pulverized fuel ash (PFA) to below 6%, thereby making it saleable for filler/building material applications without the need for postcombustion treatment. However, with only limited combustion data currently available for the multitude of potential additives, catalytic performance under pulverized fuel (PF) boiler conditions has received relatively little attention. This paper therefore compares the reactivity of catalyzed bituminous coal chars from thermogravimetric analysis (TGA) with those generated by devolatilization in a drop tube furnace (DTF). The principal aim was to explore the fundamental chemistry behind the chosen additives' relative reactivities. Accordingly, all eight of the investigated additives increased the TGA burnout rate of the TGA and DTF chars, with most of the catalysts demonstrating consistent reactivity levels across chars from both devolatilization methods. Copper(I) chloride, silver chloride, and copper nitrate were thus identified as the most successful additives tested, but it proved difficult to establish a definitive reactivity ranking. This was largely due to the use of physical mixtures for catalyst dispersion, the relatively narrow selection of additives examined, and the inherent variability of the DTF chars. Nevertheless, one crucial exception to normal additive behavior was discovered, with copper(I) chloride perceptibly deactivating during devolatilization in the DTF, even though it remained the most effective catalyst tested. As a prolonged burnout at over 1000{sup o}C was required to replicate this deactivation effect on the TGA, the phenomenon could not be detected by typical testing procedures. Subsequently, a comprehensive TGA study showed no obvious relationship between the catalyst-induced reductions in the reaction's apparent activation energy and the samples recorded burnout rates.

  14. Thermal Properties of Lunar Regolith Simulants

    NASA Technical Reports Server (NTRS)

    Street, Kenneth W., Jr.; Ray, Chandra; Rickman, Doug; Scheiman, Daniel A.

    2010-01-01

    Various high temperature chemical processes have been developed to extract oxygen and metals from lunar regolith. These processes are tested using terrestrial analogues of the regolith. But all practical terrestrial analogs contain H2O and/or OH-, the presence of which has substantial impact on important system behaviors. We have undertaken studies of lunar regolith simulants to determine the limits of the simulants to validate key components for human survivability during sustained presence on the Moon. Differential Thermal Analysis (DTA) yields information on phase transitions and melting temperatures. Thermo-Gravimetric Analysis (TGA) with Fourier Transform Infrared (FTIR) analysis provides information on evolved gas species and their evolution temperature profiles. The DTA and TGA studies included JSC-1A fine (Johnson Space Center Mare Type 1A simulant), NU-LHT-2M (National Aeronautics and Space Administration (NASA)-- United States Geological Survey (USGS)--Lunar Highlands Type 2M simulant) and its proposed feedstocks: anorthosite; dunite; high quality (HQ) glass and the norite from which HQ glass is produced. As an example, the DTA and TGA profiles for anorthosite follow. The DTA indicates exothermic transitions at 355 and 490 C and endothermic transitions at 970 and 1235 C. Below the 355 C transition, water is lost accounting for approximately 0.1 percent mass loss. Just above 490 C a second type of water is lost, presumably bound in lattices of secondary minerals along with other volatile oxides. Limited TGA-FTIR data is available at the time of this writing. For JSC-1A fine, the TGA-FTIR indicates at least two kinds of water are evolved in the 100 to 500 and the 700 to 900 C ranges. Evolution of carbon dioxide types occurs in the 250 to 545, 545 to 705, and 705 to 985 C ranges. Geologically, the results are consistent with the evolution of "water" in its several forms, CO2 from break down of secondary carbonates and magmatic, dissolved gas and glass

  15. Kinetic catalytic determination of trace Cu(II) in water samples with the thioglycolic/thiolactic acid-chromate reaction.

    PubMed

    Rustoiu-Csavdari, A; Mihai, D; Bâldea, I

    2005-04-01

    The use of two novel similar indicator reactions as applied to the kinetic determination of Cu(II) in water is investigated. The methods rely on the catalytic effect of the analyte on the oxidation of thioglycolic (TGA) and thiolactic (TLA) acids by chromate in acidic media. The extent of the reactions was followed spectrophotometrically at 345 nm. Pseudo-first-order rate coefficients, k(obsd), were determined as a function of catalyst concentration. Interference of Fe(III) and Pb(II) was suppressed by complexation with pyrophosphate. For the reaction of TGA, a linear regression for k(obsd) versus [Cu(II)] was obtained for the entire concentration range considered. Although the plot corresponding to TLA oxidation exhibits a sharp change of slope at approximately 1.8x10(-5) M Cu(II), it can still be described effectively by two linear regressions with different slopes. The reaction of TGA is more sensitive than that of TLA at low Cu(II) concentration. The opposite is true for higher catalyst contents. The detection limits were 65 microg L(-1) for TGA and of 80 microg L(-1) for TLA oxidation, respectively. The relative standard deviations, of 0.4% for TGA and 1.1% for TLA oxidation, respectively, were obtained for five replicate runs at 1000 microg L(-1). Samples of river and wastewater from the mining region of Baia-Mare, Northern Romania were analyzed using the more sensitive reaction of thioglycolic acid. Results were compared to those obtained by the officially standardized methods. Good agreement was obtained, even for an untreated sample. Measurements did not require prior separation of interfering species.

  16. CO{sub 2} capture from flue gases using three Ca-based sorbents in a fluidized bed reactor

    SciTech Connect

    Li, Z.S.; Fang, F.; Cai, N.S.

    2009-06-15

    Abstract: Experiments of CO{sub 2} capture and sorbent regeneration characteristics of limestone, dolomite, and CaO/Ca{sub 1}2Al{sub 14}O{sub 3}3 at high temperature were investigated in a thermogravimetric analyzer (TGA) and a fluidized bed reactor. The effect of reactivity decay of limestone, dolomite, and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents on CO{sub 2} capture and sorbent regeneration processes was studied. The experimental results indicated that the operation time of high efficient CO{sub 2} capture stage declined continuously with increasing of the cyclic number due to the loss of the sorbent activity, and the final CO{sub 2} capture efficiency would remain nearly constant, due to the sorbent already reaching the final residual capture capacity. After the CO{sub 2} capture step, the Ca-based sorbents need to be regenerated to be used for a subsequent cycle, and the multiple calcination processes of Ca-based sorbent under different calcination conditions are studied and discussed. Reactivity loss of limestone, dolomite and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents from a fluidized bed reactor at both mild and severe calcination conditions was compared with the TGA data. At mild calcination conditions, TGA results of sorbent reactivity loss were similar to the experimental results of fluidized bed reactor for three sorbents at 850 degrees C calcination temperature, and this indicated that TGA experimental results can be used as a reference to predict sorbent reactivity loss behavior in fluidized bed reactor. At severe calcination condition, sorbent reactivity loss behavior for limestone and dolomite from TGA compare well with the result from a fluidized bed reactor.

  17. Jordan: Background and U.S. Relations

    DTIC Science & Technology

    2012-05-03

    exploration agreement with the Jordanian government. Estonia’s Eesti Energia AS also has signed agreements on oil shale projects. See, “Amman Unlocks...Jordan focus on a variety of sectors including democracy assistance, water preservation, and education (particularly building and renovating public

  18. Jordan: Background and U.S. Relations

    DTIC Science & Technology

    2014-12-02

    Estonia’s Enefit Eesti Energia AS also has signed agreements on oil shale projects. In 2012, the Canadian company, Global Oil Shale Holdings (GOSH...variety of sectors including democracy assistance, water preservation, and education (particularly building and renovating public schools). In the

  19. Jordan: Background and U.S. Relations

    DTIC Science & Technology

    2014-01-27

    Estonia’s Enefit Eesti Energia AS also has signed agreements on oil shale projects. In 2012, the Canadian company, Global Oil Shale Holdings (GOSH...variety of sectors including democracy assistance, water preservation, and education (particularly building and renovating public schools). In the

  20. Jordan: Background and U.S. Relations

    DTIC Science & Technology

    2014-05-08

    an oil shale exploration agreement with the Jordanian government. Estonia’s Enefit Eesti Energia AS also has signed agreements on oil shale...of sectors including democracy assistance, water preservation, and education (particularly building and renovating public schools). In the democracy

  1. Jordan: Background and U.S. Relations

    DTIC Science & Technology

    2012-10-03

    signed an oil shale exploration agreement with the Jordanian government. Estonia’s Enefit Eesti Energia AS also has signed agreements on oil shale...democracy assistance, water preservation, and education (particularly building and renovating public schools). In the democracy sector, U.S. assistance

  2. Room temperature synthesis of PbSe quantum dots in aqueous solution: Stabilization by interactions with ligands

    PubMed Central

    Primera-Pedrozo, Oliva M.; Arslan, Zikri; Rasulev, Bakhtiyor; Leszczynski, Jerzy

    2011-01-01

    An aqueous route of synthesis is described for rapid synthesis of lead selenide quantum dots (PbSe QDs) at room temperature in an attempt to produce water-soluble and stable nanocrystals. Several thiol-ligands, including thioglycolic acid (TGA), thioglycerol (TGC), 3-mercaptopropionic acid (MPA), 2-mercaptoethyleamine hydrochloride (MEA), 6-mercaptohexanoic acid (MHA), and L-cysteine (L-cys), were used for capping/stabilization of PbSe QDs. The effects of the ligands on the stability of PbSe QDs were evaluated for a period of two months at room temperature under normal light conditions and at 4 °C in dark. The TGA- and MEA-capped QDs exhibited the highest stability prior to purification, almost two months when kept in dark at 4 °C. However, the stability of TGA-capped QDs was reduced substantially after purification to about 5 days under same conditions, while MEA-capped QDs did not show any significant instability. The stabilization energies of Pb-thiolate complexes determined by theoretical DFT simulations supported the experimental results. The PbSe QDs capped with TGA, MPA and MEA were successfully purified and re-dispersed in water, while those stabilized with TGC, MHA and L-cys aggregated during purification attempts. The purified PbSe QDs possess very susceptible surface resulting in poor stability for about 30 – 45 min after re-dispersion in water. In the presence of an excess of free ligand, the stability increased up to 5 days for TGA-capped QDs at pH 7.19, 9 –12 days for MPA-capped QDs at pH 7.3–7.5 and 45–47 days for MEA-capped QDs at pH 7.35. X-Ray Diffraction (XRD) results showed that the QDs possess a cubic rock salt structure with the most intense peaks located at 2θ = 25.3° (200) and 2θ = 29.2° (100). TEM images showed that the size of the QDs ranges between 5 and 10 nm. ICP-MS results revealed that Pb:Se ratio was 1.26, 1.28, 3.85, 1.18, and 1.31 for the QDs capped with TGA, MPA, MEA, L-Cys, and TGC, respectively. The proposed method

  3. Cytocompatibility of direct water synthesized cadmium selenide quantum dots in colo-205 cells

    NASA Astrophysics Data System (ADS)

    Rodriguez-Torres, Marcos R.; Velez, Christian; Zayas, Beatriz; Rivera, Osvaldo; Arslan, Zikri; Gonzalez-Vega, Maxine N.; Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Morell, Gerardo; Primera-Pedrozo, Oliva M.

    2015-06-01

    Cadmium selenide quantum dots (CdSe QDs), inorganic semiconducting nanocrystals, are alluring increased attraction due to their highly refined chemistry, availability, and super tunable optical properties suitable for many applications in different research areas, such as photovoltaics, light-emitting devices, environmental sciences, and nanomedicine. Specifically, they are being widely used in bio-imaging in contrast to organic dyes due to their high brightness and improved photo-stability, and their ability to tune their absorption and emission spectra upon changing the crystal size. The production of CdSe QDs is mostly assisted by trioctylphosphine oxide compound, which acts as solvent or solubilizing agent and renders the QDs soluble in organic compounds (such as toluene, chloroform, and hexane) that are highly toxic. To circumvent the toxicity-related factor in CdSe QDs, we report the synthesis of CdSe QDs capped with thioglycolic acid (TGA) in an aqueous medium, and their biocompatibility in colo-205 cancer cells. In this study, the [Cd2+]/[TGA] ratio was adjusted to 11:1 and the Se concentration (10 and 15 mM) was monitored in order to evaluate its influence on the optical properties and cytocompatibility. QDs resulted to be quite stable in water (after purification) and RPMI cell medium and no precipitation was observed for long contact times, making them appealing for in vitro experiments. The spectroscopy analysis, advanced electron microscopy, and X-ray diffractometry studies indicate that the final products were successfully formed exhibiting an improved optical response. Colo-205 cells being exposed to different concentrations of TGA-capped CdSe QDs for 12, 24, and 48 h with doses ranging from 0.5 to 2.0 mM show high tolerance reaching cell viabilities as high as 93 %. No evidence of cellular apoptotic pathways was observed as pointed out by our Annexin V assays at higher concentrations. Moreover, confocal microscopy analysis conducted to evaluate the

  4. Lectin-carbohydrate interactions on nanoporous gold monoliths.

    PubMed

    Tan, Yih Horng; Fujikawa, Kohki; Pornsuriyasak, Papapida; Alla, Allan J; Ganesh, N Vijaya; Demchenko, Alexei V; Stine, Keith J

    2013-07-01

    Monoliths of nanoporous gold (np-Au) were modified with self-assembled monolayers of octadecanethiol (C18-SH), 8-mercaptooctyl α-D-mannopyranoside (αMan-C8-SH), and 8-mercapto-3,6-dioxaoctanol (HO-PEG2-SH), and the loading was assessed using thermogravimetric analysis (TGA). Modification with mixed SAMs containing αMan-C8-SH (at a 0.20 mole fraction in the SAM forming solution) with either octanethiol or HO-PEG2-SH was also investigated. The np-Au monoliths modified with αMan-C8-SH bind the lectin Concanavalin A (Con A), and the additional mass due to bound protein was assessed using TGA analysis. A comparison of TGA traces measured before and after exposure of HO-PEG2-SH modified np-Au to Con A showed that the non-specific binding of Con A was minimal. In contrast, np-Au modified with octanethiol showed a significant mass loss due to non-specifically adsorbed Con A. A significant mass loss was also attributed to binding of Con A to bare np-Au monoliths. TGA revealed a mass loss due to the binding of Con A to np-Au monoliths modified with pure αMan-C8-SH. The use of mass losses determined by TGA to compare the binding of Con A to np-Au monoliths modified by mixed SAMs of αMan-C8-SH and either octanethiol or HO-PEG2-SH revealed that binding to mixed SAM modified surfaces is specific for the mixed SAMs with HO-PEG2-SH but shows a significant contribution from non-specific adsorption for the mixed SAMs with octanethiol. Minimal adsorption of immunoglobulin G (IgG) and peanut agglutinin (PNA) towards the mannoside modified np-Au monoliths was demonstrated. A greater mass loss was found for Con A bound onto the monolith than for either IgG or PNA, signifying that the mannose presenting SAMs in np-Au retain selectivity for Con A. TGA data also provide evidence that Con A bound to the αMan-C8-SH modified np-Au can be eluted by flowing a solution of methyl α-D-mannopyranoside through the structure. The presence of Con A proteins on the modified np-Au surface was

  5. Utilisation trends of rosiglitazone and pioglitazone in Australia before and after safety warnings

    PubMed Central

    2014-01-01

    Background A see on cardiovascular diseases and bladder cancer. The changes to the patterns of rosiglitazone and pioglitazone utilisation in Australia following the timing of these various health authority warnings such as the Australian Therapeutic Good Administration (TGA), European Medicines Agency (EMA) press releases or U.S. Food and Drug Administration (FDA) is unknown. This study investigated the utilisation patterns of rosiglitazone and pioglitazone in Australia before and after warnings of major drug authorities. Methods We evaluated rosiglitazone and pioglitazone dispensing using the Pharmaceutical Benefit Scheme (PBS) subsidised drug dispensing data for the Australian population from February 2004 to July 2012. The World Health Organisation Anatomic Therapeutic Chemical (ATC)/Defined Daily Dose (DDD) system was used to compare the drug utilisation patterns following the announcements of EMA, FDA, and TGA safety warnings, which first occurred in May 2007. The DDD/1000population/day were examined in a series of time-series regression analysis with the drug safety warnings specified as interventions. Results Rosiglitazone utilisation increased steadily from 2004 until reaching a peak at 1.96/1000population/day in January 2007. Then rosiglitazone use decreased significantly after the initial EMA press release and FDA warning on cardiovascular risk in May 2007 (with a 15.04% average monthly decline, p-value <0.001), however use did not significantly decrease after the TGA warning or subsequent EMA and FDA warnings. Pioglitazone utilisation proceeded rosiglitazone in September 2008 and remained above 1.5/1000/day during 2009–2010. However, pioglitazone utilisation has slightly declined after the FDA, EMA, and TGA warnings related to bladder cancer. Conclusions Drug safety warnings were associated with a decrease in rosiglitazone and pioglitazone utilisation in Australia. Rosiglitazone began to decline prior to TGA warnings in December 2007, which suggests

  6. Room temperature synthesis of PbSe quantum dots in aqueous solution: stabilization by interactions with ligands

    NASA Astrophysics Data System (ADS)

    Primera-Pedrozo, Oliva M.; Arslan, Zikri; Rasulev, Bakhtiyor; Leszczynski, Jerzy

    2012-02-01

    An aqueous route of synthesis is described for rapid synthesis of lead selenide quantum dots (PbSe QDs) at room temperature in an attempt to produce water-soluble and stable nanocrystals. Several thiol-ligands, including thioglycolic acid (TGA), thioglycerol (TGC), 3-mercaptopropionic acid (MPA), 2-mercaptoethylamine hydrochloride (MEA), 6-mercaptohexanoic acid (MHA), and l-cysteine (l-cys), were used for capping/stabilization of PbSe QDs. The effects of the ligands on the stability of PbSe QDs were evaluated for a period of two months at room temperature under normal light conditions and at 4 °C in the dark. The TGA- and MEA-capped QDs exhibited the highest stability prior to purification, almost two months when kept in the dark at 4 °C. However, the stability of TGA-capped QDs was reduced substantially after purification to about 5 days under the same conditions, while MEA-capped QDs did not show any significant instability. The stabilization energies of Pb-thiolate complexes determined by theoretical DFT simulations supported the experimental results. The PbSe QDs capped with TGA, MPA and MEA were successfully purified and re-dispersed in water, while those stabilized with TGC, MHA and l-cys aggregated during purification attempts. The purified PbSe QDs possess very susceptible surface resulting in poor stability for about 30-45 min after re-dispersion in water. In the presence of an excess of free ligand, the stability increased up to 5 days for TGA-capped QDs at pH 7.19, 9-12 days for MPA-capped QDs at pH 7.3-7.5 and 45-47 days for MEA-capped QDs at pH 7.35. X-Ray diffraction (XRD) results showed that the QDs possess a cubic rock salt structure with the most intense peaks located at 2θ = 25.3° (200) and 2θ = 29.2° (100). TEM images showed that the size of the QDs ranges between 5 and 10 nm. ICP-MS results revealed that Pb : Se ratios were 1.26, 1.28, 3.85, 1.18, and 1.31 for the QDs capped with TGA, MPA, MEA, l-cys, and TGC, respectively. The proposed

  7. Impact of mass screening for gluten-sensitive enteropathy in working population

    PubMed Central

    Mariné, Meritxell; Fernández-Bañares, Fernando; Alsina, Montserrat; Farré, Carme; Cortijo, Montserrat; Santaolalla, Rebeca; Salas, Antonio; Tomàs, Margarita; Abugattas, Elias; Loras, Carme; Ordás, Ingrid; Viver, Josep M; Esteve, Maria

    2009-01-01

    AIM: To assess: (1) frequency and clinical relevance of gluten sensitive enteropathy (GSE) detected by serology in a mass screening program; (2) sensitivity of antitransglutaminase (tTGA) and antiendomysium antibodies (EmA); and (3) adherence to gluten-free diet (GFD) and follow-up. METHODS: One thousand, eight hundred and sixty-eight subjects recruited from an occupational health department underwent analysis for tTGA and EmA and, if positive, duodenal biopsy, DQ2/DQ8 genotyping, clinical feature recording, blood tests, and densitometry were performed. Since > 98% of individuals had tTGA < 2 U/mL, this value was established as the cut-off limit of normality and was considered positive when confirmed twice in the same sample. Adherence to a GFD and follow up were registered. RESULTS: Twenty-six (1.39%) subjects had positive tTGA and/or EmA, and 21 underwent biopsy: six Marsh III (one IIIa, four IIIb, one IIIc), nine Marsh I and six Marsh 0 (frequency of GSE 1:125). The sensitivity of EmA for GSE was 46.6% (11.1% for Marsh I, 100% for Marsh III), while for tTGA, it was 93.3% (88.8% for Marsh I, 100% for Marsh III). All 15 patients with abnormal histology had clinical features related to GSE. Marsh I and III subjects had more abdominal pain than Marsh 0 (P = 0.029), and a similar trend was observed for distension and diarrhea. No differences in the percentage of osteopenia were found between Marsh I and III (P = 0.608). Adherence to follow-up was 69.2%. Of 15 GSE patients, 66.7% followed a GFD with 80% responding to it. CONCLUSION: GSE in the general population is frequent and clinically relevant, irrespective of histological severity. tTGA is the marker of choice. Mass screening programs are useful in identifying patients who can benefit from GFD and follow-up. PMID:19294762

  8. Discriminating secondary from primary water in volcanic glass using thermogravimetric analysis

    NASA Astrophysics Data System (ADS)

    Giachetti, T.; Gonnermann, H. M.; Gardner, J. E.; Shea, T.; Daniller-Varghese, M.

    2013-12-01

    Matrix-glass water in pyroclasts can include both primary (magmatic) and secondary (meteoric) water. Quantitative discrimination between magmatic and meteoric water is essential to interpret magma degassing processes, but remains challenging. Analyses of D/H isotopic ratios or water speciation help assess whether a texturally intact glass has been rehydrated, but we yet to correct for the extent of rehydration quantitatively, largely because the diffusivity of water at low temperatures (<400°C) is poorly understood. We present new results on the rehydration of rhyolitic pumices using thermogravimetric analysis (TGA). TGA quantifies precisely the mass lost from volatile exsolution (almost exclusively water in our case, as determined by both mass spectrometry and infrared spectroscopy) from a given sample heated to a specified temperature at specified rate. TGA has been used previously to discriminate between magmatic and meteoric water in silicic glasses, under the assumption that exsolution of meteoric water only occurs at T<550°C. Analyzed samples include crystal-free rhyolitic Plinian pumices from Glass Mountain (1.1 ka), Valles Caldera (50-60 ka) and Long Valley caldera (760 ka). All samples were crushed to <125 μm grains, and analyzed by TGA for temperatures up to 1000°C, using a heating rate of 20°C/min. The total weight loss attributed to water ranges from 1.3 wt% in pumice from Glass Mountain to >4.5 wt% in pumice from Valles Caldera. For all samples, >80% of the total water is lost far below 550°C, the first derivative of the mass loss always showing a major degassing peak between 210-320°C, followed by a smaller peak between 430-670°C. Moreover, the TGA curve of an obsidian from Glass Mountain, first dehydrated by heating the sample to 1000°C, and then experimentally hydrated to 3.9 wt% at high temperature and pressure (i.e., containing only ';magmatic' water), also shows that ~85% of the water is lost below 550°C, with a major peak around 380

  9. Cytocompatibility of direct water synthesized cadmium selenide quantum dots in colo-205 cells.

    PubMed

    Rodriguez-Torres, Marcos R; Velez, Christian; Zayas, Beatriz; Rivera, Osvaldo; Arslan, Zikri; Gonzalez-Vega, Maxine N; Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Morell, Gerardo; Primera-Pedrozo, Oliva M

    2015-06-01

    Cadmium selenide quantum dots (CdSe QDs), inorganic semiconducting nanocrystals, are alluring increased attraction due to their highly refined chemistry, availability, and super tunable optical properties suitable for many applications in different research areas, such as photovoltaics, light-emitting devices, environmental sciences, and nanomedicine. Specifically, they are being widely used in bio-imaging in contrast to organic dyes due to their high brightness and improved photo-stability, and their ability to tune their absorption and emission spectra upon changing the crystal size. The production of CdSe QDs is mostly assisted by trioctylphosphine oxide compound, which acts as solvent or solubilizing agent and renders the QDs soluble in organic compounds (such as toluene, chloroform, and hexane) that are highly toxic. To circumvent the toxicity-related factor in CdSe QDs, we report the synthesis of CdSe QDs capped with thioglycolic acid (TGA) in an aqueous medium, and their biocompatibility in colo-205 cancer cells. In this study, the [Cd(2+)]/[TGA] ratio was adjusted to 11:1 and the Se concentration (10 and 15 mM) was monitored in order to evaluate its influence on the optical properties and cytocompatibility. QDs resulted to be quite stable in water (after purification) and RPMI cell medium and no precipitation was observed for long contact times, making them appealing for in vitro experiments. The spectroscopy analysis, advanced electron microscopy, and X-ray diffractometry studies indicate that the final products were successfully formed exhibiting an improved optical response. Colo-205 cells being exposed to different concentrations of TGA-capped CdSe QDs for 12, 24, and 48 h with doses ranging from 0.5 to 2.0 mM show high tolerance reaching cell viabilities as high as 93 %. No evidence of cellular apoptotic pathways was observed as pointed out by our Annexin V assays at higher concentrations. Moreover, confocal microscopy analysis conducted to evaluate

  10. Cytocompatibility of direct water synthesized cadmium selenide quantum dots in colo-205 cells

    PubMed Central

    Rodriguez-Torres, Marcos R.; Velez, Christian; Zayas, Beatriz; Rivera, Osvaldo; Arslan, Zikri; Gonzalez-Vega, Maxine N.; Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Morell, Gerardo

    2015-01-01

    Cadmium selenide quantum dots (CdSe QDs), inorganic semiconducting nanocrystals, are alluring increased attraction due to their highly refined chemistry, availability, and super tunable optical properties suitable for many applications in different research areas, such as photovoltaics, light-emitting devices, environmental sciences, and nanomedicine. Specifically, they are being widely used in bio-imaging in contrast to organic dyes due to their high brightness and improved photo-stability, and their ability to tune their absorption and emission spectra upon changing the crystal size. The production of CdSe QDs is mostly assisted by trioctylphosphine oxide compound, which acts as solvent or solubilizing agent and renders the QDs soluble in organic compounds (such as toluene, chloroform, and hexane) that are highly toxic. To circumvent the toxicity-related factor in CdSe QDs, we report the synthesis of CdSe QDs capped with thioglycolic acid (TGA) in an aqueous medium, and their biocompatibility in colo-205 cancer cells. In this study, the [Cd2+]/[TGA] ratio was adjusted to 11:1 and the Se concentration (10 and 15 mM) was monitored in order to evaluate its influence on the optical properties and cytocompatibility. QDs resulted to be quite stable in water (after purification) and RPMI cell medium and no precipitation was observed for long contact times, making them appealing for in vitro experiments. The spectroscopy analysis, advanced electron microscopy, and X-ray diffractometry studies indicate that the final products were successfully formed exhibiting an improved optical response. Colo-205 cells being exposed to different concentrations of TGA-capped CdSe QDs for 12, 24, and 48 h with doses ranging from 0.5 to 2.0 mM show high tolerance reaching cell viabilities as high as 93 %. No evidence of cellular apoptotic pathways was observed as pointed out by our Annexin V assays at higher concentrations. Moreover, confocal microscopy analysis conducted to evaluate the

  11. Monitoring of changes in substrate characteristics during mushroom compost production.

    PubMed

    Lyons, Gary A; Sharma, H S Shekhar; Kilpatrick, Mairead; Cheung, Linda; Moore, Solveig

    2006-06-28

    Substrates from three mushroom compost facilities in Northern Ireland, employing similar production technologies, were examined to assess the quality of the compost produced. Biochemical investigation highlighted changes in substrates through each step of the production cycle. Thermogravimetric analysis (TGA) provided useful information on fiber fraction content and extent of substrate breakdown. A comparison of productivity, chemical, and thermal data permitted assessment of the degree of bioconversion that had occurred in the decomposition from raw materials to finished substrate for each composter. One of the composters consistently produced substrate of inferior quality compared to the other two, indicating production inefficiencies during composting. Results demonstrated that allied to chemical analyses, TGA is a useful tool, providing valuable information on substrate quality and, in particular, for studying the bioconversion of lignocellulosic materials in mushroom compost.

  12. Kinetics of (3-aminopropyl)triethoxylsilane (APTES) silanization of superparamagnetic iron oxide nanoparticles.

    PubMed

    Liu, Yue; Li, Yueming; Li, Xue-Mei; He, Tao

    2013-12-10

    Silanization of magnetic ironoxide nanoparticles with (3-aminopropyl)triethoxylsilane (APTES) is reported. The kinetics of silanization toward saturation was investigated using different solvents including water, water/ethanol (1/1), and toluene/methanol (1/1) at different reaction temperature with different APTES loading. The nanoparticles were characterized by Fourier transform infrared spectroscopy, vibrating sample magnetometry, transmission electron microscopy, and thermal gravimetric analysis (TGA). Grafting density data based on TGA were used for the kinetic modeling. It is shown that initial silanization takes place very fast but the progress toward saturation is very slow, and the mechanism may involve adsorption, chemical sorption, and chemical diffusion processes. The highest equilibrium grafting density of 301 mg/g was yielded when using toluene/methanol mixture as the solvent at a reaction temperature of 70 °C.

  13. Chemical modification of silica gel with synthesized new Schiff base derivatives and sorption studies of cobalt (II) and nickel (II)

    NASA Astrophysics Data System (ADS)

    Kursunlu, Ahmed Nuri; Guler, Ersin; Dumrul, Hakan; Kocyigit, Ozcan; Gubbuk, Ilkay Hilal

    2009-08-01

    In this study, three Schiff base ligands and their complexes were synthesized and characterized by infrared spectroscopy (IR), thermogravimetric analyses (TGA), nuclear magnetic resonance (NMR), elemental analysis and magnetic susceptibility apparatuses. Silica gel was respectively modified with Schiff base derivatives, (E)-2-[(2-chloroethylimino)methyl]phenol, (E)-4-[(2-chloroethylimino)methyl]phenol and N, N'-[1,4-phenilendi(E)methylidene]bis(2-chloroethanamine), after silanization of silica gel by (3-aminopropyl)trimethoxysilane (APTS) by using a suitable method. Characterization of the surface modification was also performed with IR, TGA and elemental analysis. The immobilized surfaces were used for Co(II) and Ni(II) sorption from aqueous solutions and values of sorption were detected by atomic absorption spectrometer (AAS).

  14. Radiation grafted membranes for polymer electrolyte fuel cells, ex situ and in situ characterization

    SciTech Connect

    Scherer, G.G.; Buchi, F.N.; Gupta, B.

    1993-12-31

    Proton conducting membranes for polymer electrolyte fuel cells were prepared by radiation grafting of styrene/divinylbenzene onto Telon-FEP films and subsequent sulfonation. Films with degrees of grafting up to 50% were obtained and characterized FTIR-ATR with respect to their homogeneity, by DSC and TGA with respect to their thermal properties. After sulfonation thermal stability was again probed by TGA in combination with one-line FTIR and MS. Water uptake and protonic resistivity were determined after pretreatment in boiling water. The decrease in resistivity with increasing degree of grafting is mainly due to an increasing proton mobility. The membranes were tested in H{sub 2}/O{sub 2} fuel cells (ambient pressure, 60 to 90{degrees}C) with respect to their short- and long-term (up to 1000 h) polarization performance. The results of the ex and in situ characterization will be presented and discussed.

  15. Honeycomb structural composite polymer network of gelatin and functional cellulose ester for controlled release of omeprazole.

    PubMed

    Zhuang, Chen; Shi, Chengmei; Tao, Furong; Cui, Yuezhi

    2017-01-05

    The functionalized cellulose ester MCN was firstly synthesized and used to cross-link gelatin by amidation between -NH2 in gelatin and active ester groups in MCN to form a composite polymer network Gel-MCN, which was confirmed by Van Slyke method, FTIR, XRD and TGA-DTG spectra. The model drug omeprazole was loaded in Gel-MCN composites mainly by electrostatic interaction and hydrogen bonds, which were certified by FTIR, XRD and TGA-DSC. Thermal stability, anti-biodegradability, mechanical property and surface hydrophobicity of the composites with different cross-linking extents and drug loading were systematically investigated. SEM images demonstrated the honeycomb structural cells of cross-linked gelatin networks and this ensured drug entrapment. The drug release mechanism was dominated by a combined effect of diffusion and degradation, and the release rate decreased with cross-linking degree increased. The developed drug delivery system had profound significance in improving pesticide effect and bioavailability of drugs.

  16. Redox heme-proteins mediated fluorescence of CdSe/ZnS quantum dots.

    PubMed

    Qin, Lixia; He, Luwei; Ji, Congcong; Li, Xiangqing; Kang, Shi-Zhao; Mu, Jin

    2014-04-05

    The redox properties of cytochrome c (Cyt c), hemoglobin (Hb) and myoglobin (Mb) were studied based on electrostatic interactions between Thioglycolic acid (TGA) capped CdSe/ZnS quantum dots (QDs) and proteins. Results indicated that only Cyt c quenched the fluorescence of the QDs at pH>8.0. Under the optimized conditions, a significant fluorescence recovery of the QDs' system was observed when the reduced form of Cyt c incubated with TGA capped QDs, however, the reduced state of Hb and Mb resulted in a more fluorescence quenching on the same size of QDs. Interestingly, the fluorescence changes of QDs-proteins could be switched by modulating the redox potentials of proteins-attached QDs. Moreover, only the oxidized Cyt c form was reduced by the generated O2(-) that significantly enhanced the fluorescence of the QDs' system, which was also demonstrated by fluorescence imaging in HeLa cells.

  17. Kinetic models comparison for steam gasification of coal/biomass blend chars.

    PubMed

    Xu, Chaofen; Hu, Song; Xiang, Jun; Yang, Haiping; Sun, Lushi; Su, Sheng; Wang, Baowen; Chen, Qindong; He, Limo

    2014-11-01

    The non-isothermal thermogravimetric method (TGA) was applied to different chars produced from lignite (LN), sawdust (SD) and their blends at the different mass ratios in order to investigate their thermal reactivity under steam atmosphere. Through TGA analysis, it was determined that the most prominent interaction between sawdust and lignite occurred at the mass ratio of sawdust/lignite as 1:4, but with further dose of more sawdust into its blends with lignite, the positive interaction deteriorated due to the agglomeration and deactivation of the alkali mineral involved in sawdust at high steam gasification temperature. Through systematic comparison, it could be observed that the random pore model was the most suitable among the three gas-solid reaction models adopted in this research. Finally, rational kinetic parameters were reached from these gas-solid reaction models, which provided a basis for design and operation of the realistic system of co-gasification of lignite and sawdust in this research.

  18. Mass Production of Carbon Nanofibers Using Microwave Technology.

    PubMed

    Mubarak, N M; Abdullah, E C; Sahu, J N; Jayakumar, N S; Ganesan, P

    2015-12-01

    Carbon nanotubes (CNFs) were produced by gas phase single stage microwave assisted chemical vapour deposition (MA-CVD) using ferrocene as a catalyst and acetylene (C2H2) and hydrogen (H2) as precursor gases. The effect of the process parameters such as microwave power, radiation time, and gas ratio of C2H2/H2 was investigated. The CNFs were characterized using scanning and transmission electron microscopy (TEM), and by thermogravimetric analysis (TGA). Results reveal that the optimized conditions for CNF production were 1000 W reaction power, 35 min radiation time, and 0.8 gas ratio of C2H2/H2. TEM analyses revealed that the uniformly dispersed CNFs diameters ranging from 115-131 nm. The TGA analysis showed that the purity of CNF produced was 93%.

  19. Enhancing mechanical properties of chitosan films via modification with vanillin.

    PubMed

    Zhang, Zhi-Hong; Han, Zhong; Zeng, Xin-An; Xiong, Xia-Yu; Liu, Yu-Jia

    2015-11-01

    The vanillin/chitosan composite films were prepared using the solvent evaporation method. The properties of the films including optical property, water vapor permeability (WVP), tensile strength (TS) and elongation at break (%E) were studied to investigate the effect of cross-linking agent of vanillin on chitosan films by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectrum (FT-IR). Results showed that the TS of composite films increased by 53.3% and the WVP decreased by 36.5% compared with pure chitosan film that were due to the formation of the dense network structure by FT-IR spectra. There were almost no changes of the thermal stability of the composite films compared with the pure chitosan film by TGA analysis. In addition, from the SEM images, it could be seen that the film with addition of vanillin with 0.5-10% concentration exhibited good compatibility.

  20. Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes

    NASA Astrophysics Data System (ADS)

    Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M. Arif

    2016-05-01

    We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.

  1. [Combustion characteristics of mixed municipal solid waste in thermogravimetric analysis and lab scale fluidized bed].

    PubMed

    Jiang, Fan; Pan, Zhonggang; Liu, Shi; Wang, Haigang

    2002-01-30

    In this paper, thermogravimetric analysis (TGA) and a lab scale fluidized bed facility were used as experimental means. The data in the two different experimental systems were introduced and compared. Experimental results show that the differences of combustion velocity among different wastes in Fluidized Bed(FB) were very small whereas in thermogravimetric analyzer the differences can not be ignored as the value range of combustion velocity variation was between 0.49 and 5.5. It took municipal solid waste 3-3.5 min to burn out in FB, but in thermogravimetric analyzer, the time was 20-25 min. It can be concluded that, in general, the behavior of a mixture of waste in TGA can be expressed by simple combination of individual components of the waste mixtures. Only minor deviations from the rule were observed. In FB, it was found that, for some mixtures, there was interference among the components during FB combustion.

  2. Pretreatment of carbon nanotubes: Effects on its properties and catalytic performances

    NASA Astrophysics Data System (ADS)

    Sulong, Tuan Syahylah Tuan; Zabidi, Noor Asmawati Mohd; Shaharun, Maizatul Shima

    2016-11-01

    The effects of pretreatment via acid and thermal treatment on the properties of multi-walled carbon nanotubes (MWCNTs) are studied using FTIR, TGA, Raman spectroscopy and TEM. Meanwhile, catalytic performances of Cu/ZnO catalysts supported on raw and treated CNTs are evaluated by CO2 hydrogenation into methanol using a fixed-bed microactivity reactor. Pretreatment of CNTs have removed caps, created defects on CNTs wall and also introduced some functional groups as confirmed by FTIR, TGA, Raman spectroscopy and TEM. However, deposition of metals into the support via incipient wetness impregnation method results in agglomeration of metal particles outside CNTs. Methanol synthesis studies (523 K, 22.5 bar) were performed and activity study revealed that catalysts supported on treated CNTs achieved CO2 conversion of 19 %.

  3. Performance and Kinetics of a solid Amine Sorbent for Carbon Dioxide Removal

    SciTech Connect

    Monazam, Esmail R.; Shadle, Lawrence J.; Siriwardane, Ranjani

    2011-10-05

    The kinetics of the reaction between CO{sub 2} and amine/bentonite particle were estimated over the range of 303–363 K from adsorption data obtained by TGA. The weight percent of amine, reaction temperature, and particle diameter were considered as experimental variables. The sorbent maximum or equilibrium CO{sub 2} uptake was found to be linearly dependent on temperature; decreasing with increasing temperature when tested in a 100% CO{sub 2} environment. Reactivity data for amine/bentonite particle with CO{sub 2} were presented and discussed. On the basis of the isothermal TGA results, reaction order and the value of activation energy have been obtained. These kinetic parameters are similar to those reported for MEA and DEA in aqueous solutions. The kinetic model was used to predict the fractional conversion at different temperature exhibiting good agreement with experimental data.

  4. Study on the conformation changes of Lysozyme induced by Hypocrellin A: The mechanism investigation

    NASA Astrophysics Data System (ADS)

    Ma, Fei; Huang, He-Yong; Zhou, Lin; Yang, Chao; Zhou, Jia-Hong; Liu, Zheng-Ming

    2012-11-01

    The interactions between Lysozyme and Hypocrellin A are investigated in details using time-resolved fluorescence, fourier transform infrared spectroscopy (FTIR), circular dichroism spectroscopy (CD), three-dimensional fluorescence spectra, and thermal gravimetric analysis (TGA) techniques. The results of time-resolved fluorescence suggest that the quenching mechanism is static quenching. FTIR and CD spectroscopy provide evidences of the reducing of α-helix after interaction. Hypocrellin A could change the micro-environmental of Lysozyme according to hydrophobic interaction between the aromatic ring and the hydrophobic amino acid residues, and the altered polypeptide backbone structures induce the reduction of α-helical structures. Moreover, TGA study further demonstrates the structure changes of Lysozyme on the effect of Hypocrellin A. This study could provide some important information for the derivatives of HA in pharmacy, pharmacology and biochemistry.

  5. Microwave-assisted synthesis of Pt/CNT nanocomposite electrocatalysts for PEM fuel cells.

    PubMed

    Zhang, Weimin; Chen, Jun; Swiegers, Gerhard F; Ma, Zi-Feng; Wallace, Gordon G

    2010-02-01

    Microwave-assisted heating of functionalized, single-wall carbon nanotubes (FCNTs) in ethylene glycol solution containing H(2)PtCl(6), led to the reductive deposition of Pt nanoparticles (2.5-4 nm) over the FCNTs, yielding an active catalyst for proton-exchange membrane fuel cells (PEMFCs). In single-cell testing, the Pt/FCNT composites displayed a catalytic performance that was superior to Pt nanoparticles supported by raw (unfunctionalized) CNTs (RCNTs) or by carbon black (C), prepared under identical conditions. The supporting single-wall carbon nanotubes (SWNTs), functionalized with carboxyl groups, were studied by thermogravimetric analysis (TGA), cyclic voltammetry (CV), and Raman spectroscopy. The loading level, morphology, and crystallinity of the Pt/SWNT catalysts were determined using TGA, SEM, and XRD. The electrochemically active catalytic surface area of the Pt/FCNT catalysts was 72.9 m(2)/g-Pt.

  6. Studies of the thermal degradation of waste rubber.

    PubMed

    Chen, Fengzhen; Qian, Jialin

    2003-01-01

    One kind of Chinese waste tire's sample was pyrolyzed under an inert atmosphere by using thermo-gravimetric apparatus (TGA) and differential thermal analysis (DTA). Different pyrolysis temperature ranges were determined according to the reaction transition temperature obtained by TGA and DTA. Then, at each temperature range, the pyrolysis gaseous products were analyzed by gas chromatography (GC). The influence of the temperature range on the relative yields of the major decomposition products is studied, and a mechanism for the formation of the main components was also investigated. The results indicate that pyrolysis of waste rubber follows the radical mechanism, and the major products are not seriously affected by increasing the temperature from room temperature to 420 degrees C and from 421 to 600 degrees C, but the degradation of blend rubber is different for each of the compositional elastomer.

  7. Evaluation of the effects of a new combustion system and catalyst on engine emissions

    SciTech Connect

    Corbo, P.; Corcione, F.E.; Vaglieco, B.M.

    1990-01-01

    The paper reports the results of an experimental investigation carried out on a four-stroke single-cylinder D.I. diesel engine (100 {times} 95mm bore {times} stroke) with the aim to evaluate the effects of a four-lobe square combustion chamber on the gaseous and particulate emissions. Fluid-dynamic behaviour of the axisymmetric toroidal and four-lobe square chambers was investigated by Laser Doppler Anemometry. Engine tests at 2000 and 3000 rpm for different state of combustion (SOC) and A/F ratio are reported. Particulate, HC and NO{sub x} emission index measured under different operating conditions are given. In addition, the volatile content of the particulates produced from the two chambers at various engine operative conditions was measured by thermogravimetric analysis (TGA). Finally, the catalytic activity of a metal-oxide-based catalyst in the combustion of particulate was also evaluated by TGA.

  8. Electrospinning of PVC with natural rubber

    NASA Astrophysics Data System (ADS)

    Othman, Muhammad Hariz; Mohamed, Mahathir; Abdullah, Ibrahim

    2013-11-01

    Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber's mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

  9. Thermal properties of hemp fiber filled polyamide 1010 biomass composites and the blend of these composites and polyamide 11 elastomer

    NASA Astrophysics Data System (ADS)

    Nishitani, Yosuke; Mukaida, Jun; Yamanaka, Toshiyuki; Kajiyama, Tetsuto; Kitano, Takeshi

    2016-03-01

    The aim of this study is to improve the performance of all inedible plants-derived materials for new engineering materials such as structural materials and tribomaterials. Thermal properties of hemp fiber filled polyamide 1010 biomass composites and the blend of these composites and plants-derived TPE were investigated experimentally. These biomass composites were extruded by a twin screw extruder and compression or injection molded. Thermal properties such as dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) of these biomass composites were evaluated. It was found that the addition of HF and the blend of bio-TPE with PA1010 have strong influence on the thermal properties such as DMA, TGA and DSC. In particular, HF has a good effect for the improvement of the thermal and mechanical properties. These properties of HF/PA1010/PA11E biomass composites are better than those of HF/PA1010/TPU ones.

  10. Investigation of Water Absorption and Diffusion in Microparticles Containing Xylitol to Provide a Cooling Effect by Thermal Analysis

    NASA Astrophysics Data System (ADS)

    Salaün, F.; Bedek, G.; Devaux, E.; Dupont, D.; Deranton, D.

    2009-08-01

    Polyurethane microparticles containing xylitol as a sweat sensor system were prepared by interfacial polymerization. The structural and thermal properties of the resultant microparticles were studied. The surface morphology and chemical structure of microparticles were investigated using an optical microscope (OM) and a Fourier-transform infrared spectroscope (FTIR), respectively. The thermal properties of samples were investigated by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC). Thus, two types of microparticles were synthesized by varying the percentage of monomers introduced. The obtained morphology is directly related to the synthesis conditions. DSC analysis indicated that the mass content of crystalline xylitol was up to 63.8 %, which resulted in a high enthalpy of dilution of 127.7 J · g-1. Furthermore, the water release rate monitored by TGA analysis was found to be faster from the microparticles than from raw xylitol. Thus, the microparticles could be applied for thermal energy storage and moisture sensor enhancement.

  11. Thermal analysis evaluation of mechanical properties changes promoted by gamma radiation on surgical polymeric textiles

    NASA Astrophysics Data System (ADS)

    Ferreira, L. M.; Casimiro, M. H.; Oliveira, C.; Cabeço Silva, M. E.; Marques Abreu, M. J.; Coelho, A.

    2002-05-01

    The large number of surgical operations with post-operative infection problems and the appearing of new infectious diseases, contribute to the development of new materials in order to answer the needs of health care services. This development must take into account the modifications promoted by sterilisation methods in materials, namely by gamma radiation. The differential scanning calorimetry (DSC) and thermogravimetry (TGA) techniques show that a nonwoven and a laminate textiles maintain a good molecular cohesion, do not showing high levels of degradation, for gamma radiation dose values lower than 100 kGy in nonwoven and 200 kGy in laminate materials. The tensile strength and the elongation decrease slowly for the nonwoven textile and decrease faster for the laminate textile for 25 and 80 kGy absorbed dose. This paper shows that the DSC and TGA techniques can be helpful for the prevision of mechanical changes occurred in the materials as a consequence of the gamma irradiation.

  12. Synthesis and characterization of Sm0.5Ba0.5MnO3-δ as anode materials for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Abdalla, A. M.; Radenahmad, N.; Abu Bakar, M. S.; . I. Petra, Pg M.; Azad, A. K.

    2016-03-01

    The material performance is a crucial issue in the current fuel cell technology, and for this reason we present this new series of Samarium family which can be used as electrode giving a high performance in a particular application. Sm0.5Ba0.5MnO3-δ was prepared by solid state reaction method and characterized by using X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Rietveld analysis of XRD data shows that the material has an Orthorhombic crystal structure with cell parameter a = 3.883(1) Å b = 3.8742(5) Å c = 7. 762(4) Å, in the Pmmm space group. TGA analyses shows that the materials is going to decrease by 0.32%. The density of the materials was calculated from structural refinement and found to be 8.372 gm/cm3.

  13. A rapid and sensitive assay for determination of doxycycline using thioglycolic acid-capped cadmium telluride quantum dots.

    PubMed

    Tashkhourian, Javad; Absalan, Ghodratollah; Jafari, Marzieh; Zare, Saber

    2016-01-05

    A rapid, simple and inexpensive spectrofluorimetric sensor for determination of doxycycline based on its interaction with thioglycolic acid-capped cadmium telluride quantum dots (TGA/CdTe QDs) has been developed. Under the optimum experimental conditions, the sensor exhibited a fast response time of <10s. The results revealed that doxycycline could quench the fluorescence of TGA/CdTe QDs via electron transfer from the QDs to doxycycline through a dynamic quenching mechanism. The sensor permitted determination of doxycycline in a concentration range of 1.9×10(-6)-6.1×10(-5)molL(-1) with a detection limit of 1.1×10(-7)molL(-1). The sensor was applied for determination of doxycycline in honey and human serum samples.

  14. New Poly(amide-imide)/Nanocomposites Reinforced Silicate Nanoparticles Based on N-pyromellitimido-L-phenyl Alanine Containing Ether Moieties

    NASA Astrophysics Data System (ADS)

    Faghihi, Khalil; Shabanian, Meisam; Dadfar, Ehsan

    2012-02-01

    A series of Poly(amide-imide)/montmorillonite nanocomposites containing N-pyromellitimido-L-phenyl alanine moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) 5 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N-pyromellitimido-L-phenyl alanine 3 with 4,4'-diamino diphenyl ether 4 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). The resulting nanocomposite films were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that organo-modified clay was dispersed homogeneously in PAI matrix. TGA indicated an enhancement of thermal stability of new nanocomposites compared with the pure polymer.

  15. Photo and Thermal Behavior of New Reinforced Polyamide-nanocomposite Montmorillonite on 2,3-Pyrazin Dicarboxylic Acid

    NASA Astrophysics Data System (ADS)

    Faghihi, Khalil; Samiei, Mojtaba; Hajibeygi, Mohsen

    2012-06-01

    Two new samples of reinforce polyamidemontmorillonite nanocomposites were synthesized by a convenient solution intercalation technique. Polyamide (PA) 3 as a source of polymer matrix was synthesized by the direct polycondensation reaction of pyrazine 2,3-dicarboxylic acid 1 with 4,4'-diamino diphenyl ether 2 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). The resulting nanocomposite films were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that organo-modified clay was dispersed homogeneously in PA matrix. TGA indicated an enhancement of thermal stability of new nanocomposites compared with the pure polymer.

  16. Oxy-combustion of biomass in a circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Kosowska-Golachowska, Monika; Kijo-Kleczkowska, Agnieszka; Luckos, Adam; Wolski, Krzysztof; Musiał, Tomasz

    2016-03-01

    The objective of this study was to investigate combustion characteristics of biomass (willow, Salix viminalis) burnt in air and O2/CO2 mixtures in a circulating fluidized bed (CFB). Air and oxy-combustion characteristics of wooden biomass in CFB were supplemented by the thermogravimetric and differential thermal analyses (TGA/DTA). The results of conducted CFB and TGA tests show that the composition of the oxidizing atmosphere strongly influences the combustion process of biomass fuels. Replacing N2 in the combustion environment by CO2 caused slight delay (higher ignition temperature and lower maximum mass loss rate) in the combustion of wooden biomass. The combustion process in O2/CO2 mixtures at 30% and 40% O2 is faster and shorter than that at lower O2 concentrations.

  17. Preparation of Microstructure Molds of Montmorillonite/Polyethylene Glycol Diacrylate and Multi-Walled Carbon Nanotube/Polyethylene Glycol Diacrylate Nanocomposites for Miniaturized Device Applications.

    PubMed

    Kim, Young Ho; Sohn, Jeong-Woo; Woo, Youngjae; Hong, Joo-Hyun; Kim, Gyu Man; Kang, Bong Keun; Park, Juyoung

    2015-10-01

    Environmentally friendly microstructure molds with montmorillonite (MMT) or multi-walled carbon nanotube (MWCNT) reinforced polyethylene glycol diacrylate (PEGDA) nanocomposites have been prepared for miniaturized device applications. The micropatterning of MMT/PEGDA and MWCNT/PEGDA with 0.5 to 2.0 wt% of MMTs and MWCNTs was achieved through a UV curing process with micro-patterned masks. Hexagonal dot arrays and complex patterns for microstructures of the nanocomposites were produced and characterized with an optical microscope; their thermal properties were studied by thermogravimetric analysis (TGA). The TGA results showed that these nanocomposites were thermally stable up to 350 °C. Polydimethylsiloxane thin replicas with different microstructures were prepared by a casting method using the microstructured nanocomposites as molds. It is considered that these microstructure molds of the nanocomposites can be used as microchip molds to fabricate nanobio-chips and medical diagnostic chip devices.

  18. Oxidation Kinetics and Strength Degradation of Carbon Fibers in a Cracked Ceramic Matrix Composite

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.

    2003-01-01

    Experimental results and oxidation modeling will be presented to discuss carbon fiber susceptibility to oxidation, the oxidation kinetics regimes and composite strength degradation and failure due to oxidation. Thermogravimetric Analysis (TGA) was used to study the oxidation rates of carbon fiber and of a pyro-carbon interphase. The analysis was used to separately obtain activation energies for the carbon constituents within a C/SiC composite. TGA was also conducted on C/SiC composite material to study carbon oxidation and crack closure as a function of temperature. In order to more closely match applications conditions C/SiC tensile coupons were also tested under stressed oxidation conditions. The stressed oxidation tests show that C/SiC is much more susceptible to oxidation when the material is under an applied load where the cracks are open and allow for oxygen ingress. The results help correlate carbon oxidation with composite strength reduction and failure.

  19. Preparation and characterization of self-emulsified waterborne nitrocellulose.

    PubMed

    Ma, Sude; Song, Guolin; Feng, Ningbo

    2012-06-05

    Waterborne nitrocellulose (WNC) dispersion was successfully synthesized by self emulsification and reaction among isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA) and nitrocellulose (NC). The WNC was characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermal gravimetric analysis (TGA), etc. The WNC dispersion has Z-average particle size of 133 nm approximately and distribution index of 0.152. It is indicated by TEM that the cured WNC particles show a core-shell structure, in which hydrophobic component is encapsulated by the hydrophilic carboxyl. FTIR confirms that the reactions (i.e. IPDI and NC, IPDI and DMPA) have occurred, the - NCO group of IPDI has been consumed totally and the backbone of NC is retained. TGA reveals that the cross-linked WNC film has better thermal resistance, and the water resistance measurement confirms that it has weaker water-sensitivity.

  20. Low energy ion beam induced changes in structural and thermal properties of polycarbonate

    NASA Astrophysics Data System (ADS)

    Reheem, A. M. Abdel; Atta, A.; Maksoud, M. I. A. Abdel

    2016-10-01

    The aim of the present study is extended for obtaining relation between the collision of ion beam with polycarbonate polymer (PC) and the introduced modification of technological applications. Polycarbonate films are irradiated by a 6 keV argon ion beam extracted from locally design cold cathode ion source with different ion fluences. The films are characterized using X-ray Diffraction (XRD), Mechanical tester, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The increase in ion beam irradiation leads to an increase in the tensile strength and reduction in elongation at break for PC. TGA Analysis shows that the thermal decomposition temperature of irradiated polycarbonate changes with ion fluence. The DSC graphs show improvements in thermal stability with increase in the activation energy after ion beam irradiation. Ion penetration depths and distributions of scattered atoms are calculated using SRIM Monte Carlo simulation programs.

  1. Investigation on actuation and thermo-mechanical behaviour of Shape Memory Alloy spring using hot water

    NASA Astrophysics Data System (ADS)

    Chouhan, Priya; Nath, Tameshwer; Lad, B. K.; Palani, I. A.

    2016-09-01

    In this paper, hot water is used as an actuation media for Shape memory alloy and its impact on the morphology of structure of Nitinol Shape Memory Alloy (SMA), is presented. With hot water actuation as the temperature reaches 70-80°C, spring gets fully compressed for the first few cycles followed by a displacement loss in actuation. This actuation loss is then studied with different characterization methods such as Thermo Gravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). With SEM results, it can be inferred that the energy source is not deteriorating the structure. Results observed from TGA shows high oxygen content at lower temperature limits with hot water actuation which suggest the need of conducting experiments in inert atmosphere. As a possible mechanism, a new actuation medium is introduced and various results can be seen in the paper discussed below.

  2. Co-pyrolysis of pine sawdust and lignite in a thermogravimetric analyzer and a fixed-bed reactor.

    PubMed

    Song, Yuyao; Tahmasebi, Arash; Yu, Jianglong

    2014-12-01

    Co-pyrolysis characteristics of lignite and pine sawdust were studied in a TGA and a fixed-bed reactor. The effects of pyrolysis temperature and blending ratio on the yield and composition of pyrolysis products (gas, tar, and char) were investigated. TGA experiments showed that pine sawdust decomposition took place at lower temperatures compared to lignite. With increasing the pine sawdust content in the blend, the DTG peaks shifted towards lower temperatures due to synergetic effect. In fixed-bed experiments, the synergetic effect increased the yield of volatile matter compared to the calculated values. The major gases released at low temperatures were CO2 and CO. However, hydrogen was the primary gaseous product at higher temperatures. During co-pyrolysis, concentrations of benzene, naphthalene, and hydrocarbons in the tar decreased, accompanied by an increase in phenols and guaiacol concentrations. With increasing pyrolysis temperature, the OH, aliphatic CH, CO, and CO functional groups in char decomposed substantially.

  3. Tank 241-B-109, cores 169 and 170 analytical results for the final report

    SciTech Connect

    Nuzum, J.L.

    1997-01-20

    This document is the final laboratory report for tank 241-B-109. Push mode core segments were removed from risers 4 and 7 between August 22, 1996, and August 27, 1996. Segments were received and extruded at 222-S Analytical Laboratory. Analyses were performed in accordance with Tank 241-B-109 Push Mode Core Sampling and Analysis Plan (TSAP) and Tank Safety Screening Data Quality Objective (DQO). The results for primary safety screening data, including differential scanning calorimetry (DSC) analyses, thermogravimetric analyses (TGA), bulk density determinations, and total alpha activity analyses for each subsegment, were presented in the 45-Day report (Rev. 0 of this document). The 45-Day report is included as Part II of this revision. The raw data for DSC and TGA is found in Part II of this report. The raw data for all other analyses are included in this revision.

  4. Quantification of systemic right ventricle by echocardiography.

    PubMed

    Iriart, Xavier; Roubertie, François; Jalal, Zakaria; Thambo, Jean-Benoit

    2016-02-01

    Improvements in cardiac imaging have recently focused a great interest on the right ventricle (RV). In patients with congenital heart disease, the right ventricle (RV) may support the systemic circulation (systemic RV). There are 2 different anatomic conditions providing such physiology: the congenitally corrected transposition of the great arteries (ccTGA) and the TGA surgically corrected by atrial switch. During the last decades, evidence is accumulating that progressive systemic RV failure develops leading to considerable morbidity and mortality. Various imaging modalities have been used to evaluate the systemic RV, but echocardiography is still predominantly used in clinical practice, allowing an anatomic and functional approach of the systemic RV function and the potential associated anomalies. The goal of this review is to offer a clinical perspective of the non-invasive evaluation of the systemic RV by echocardiography.

  5. Electrospinning of PVC with natural rubber

    SciTech Connect

    Othman, Muhammad Hariz; Abdullah, Ibrahim; Mohamed, Mahathir

    2013-11-27

    Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber’s mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

  6. Compatibility study of paracetamol, chlorpheniramine maleate and phenylephrine hydrochloride in physical mixtures.

    PubMed

    de Oliveira, G G G; Feitosa, A; Loureiro, K; Fernandes, A R; Souto, E B; Severino, P

    2017-01-01

    Paracetamol (PAR), phenylephrine hydrochloride (PHE) and chlorpheniramine maleate (CPM) are commonly used in clinical practice as antipyretic and analgesic drugs to ameliorate pain and fever in cold and flu conditions. The present work describes the use of thermal analysis for the characterization of the physicochemical compatibility between drugs and excipients during the development of solid dosage forms. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to study the thermal stability of the drug and of the physical mixture (drug/excipients) in solid binary mixtures (1:1). DSC thermograms demonstrated reproducible melting event of the prepared physical mixture. Starch, mannitol, lactose and magnesium stearate influence thermal parameters. Information recorded from the derivative thermogravimetric (DTG) and TGA curves demonstrated the decomposition of drugs in well-defined thermal events, translating the suitability of these techniques for the characterization of the drug/excipients interactions.

  7. Myocardial hypoperfusion detected by cardiac computed tomography in an adult patient with heart failure after classic repair for corrected transposition of the great arteries.

    PubMed

    Okayama, Satoshi; Seno, Ayako; Soeda, Tsunenari; Takami, Yasuhiro; Horii, Manabu; Uemura, Shiro; Saito, Yoshihiko

    2011-08-01

    A 69-year-old male with a history of classic repair for corrected transposition of the great arteries (TGA) arrived at our hospital with dyspnoea upon exertion. Echocardiography revealed severe dilation and diffuse hypokinesis of the systemic ventricle without obvious valvular dysfunction. Cardiac computed tomography (CT) revealed no significant stenosis. However, the morphological right coronary artery (CA) on the left side was unequally distributed to the large systemic ventricle and was mostly obscured, especially on the anterior wall. A low attenuation area in the anterior wall of the systemic ventricle and prominent trabeculations suggested ischaemia or infarction. We considered that chronic myocardial hypoperfusion due to an inadequate coronary arterial supply was one cause of the exacerbated heart failure long after the classic repair. Cardiac CT is useful for evaluating the distribution of the CA and to predict blood supply to the myocardium in corrected TGA.

  8. The Role of ERG and CXCR4 in Prostate Cancer Progression

    DTIC Science & Technology

    2013-06-01

    glyceraldehyde 3- phosphate dehydrogenase (GAPDH), 5′-AAG GTC ATC CCT GAG CTG AA-3′ and 5′-TGA CAA AGT GGT CGT TGA GG- 3′. Real-time PCR analysis was performed...ELEMENT NUMBER 6 . AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER E-Mail: 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Accomplishments………………………………………….…….. 6 Reportable Outcomes……………………………………………………………… 6 Conclusion…………………………………………………………………………… 7 References

  9. Synthesis of double-clickable functionalised graphene oxide for biological applications† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5cc05412e Click here for additional data file.

    PubMed Central

    Mei, Kuo-Ching; Rubio, Noelia; Costa, Pedro M.; Kafa, Houmam; Abbate, Vincenzo; Festy, Frederic; Bansal, Sukhvinder S.; Hider, Robert C.

    2015-01-01

    Azide- and alkyne-double functionalised graphene oxide (Click2 GO) was synthesised and characterised with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and Raman spectroscopy. Fourteen-percentage increase in azide content was found, after pre-treatment of GO with meta-chloroperoxybenzoic acid (mCPBA), determined with elemental analysis. No effect on A549 cell viability was found, up to 100 μg mL–1 and 72 h of incubation, determined with the modified lactate dehydrogenase (mLDH) assay. Two sequential copper(i) catalysed azide–alkyne cycloaddition (CuAAC) reactions were performed to conjugate the propargyl-modified blood–brain barrier targeting peptide Angiopep-2, and a bis-azide polyethylene glycol (M W = 3500), to the Click2 GO. The final conjugate was characterised with ATR-FTIR and TGA. PMID:26295072

  10. Semantic memory and frontal executive function during transient global amnesia.

    PubMed Central

    Hodges, J R

    1994-01-01

    To assess semantic memory and frontal executive function, two patients underwent neuropsychological testing during transient global amnesia (TGA) and after an interval of 6-8 weeks. In spite of a profound deficit in anterograde verbal and non-verbal memory, semantic memory was normal, as judged by category fluency measures, picture naming, and picture-word and picture-picture matching, and reading ability was normal. Similarly, there were no deficits on a number of tests known to be sensitive to frontal executive dysfunction. A hexamethylpropyleneamine-oxime (HMPAO) single photon emission CT (SPECT) scan, obtained on one patient 24 hours post-TGA, showed focal left temporal lobe hypoperfusion which had resolved three months later. The observed dissociation between episodic and semantic memory is discussed in the light of contemporary cognitive theories of memory organisation. PMID:8201333

  11. Polyacrylamide grafting of modified graphene oxides by in situ free radical polymerization

    SciTech Connect

    Tang, Mingyi; Xu, Xiaoyang; Wu, Tao; Zhang, Sai; Li, Xianxian; Li, Yi

    2014-12-15

    Highlights: • Graphene oxide (GO) was modified by chemical reactions to functionalized GO (FGO). • The FGOs and the GO were then subjected to in situ free radical polymerization. • Hydroxyl groups of GO were the most reactive grafting sites. - Abstract: Graphene oxide (GO) was modified using chemical reactions to obtain three types of functionalized GO sheets (FGO). The FGO sheets and the GO were then subjected to in situ free radical polymerization in order to study the grafting polymerization. The FGO and grafted-.FGO were analyzed with Fourier transform infrared spectroscopy, scanning electronic microscopy, thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The grafting percentages in the materials were calculated using the TGA and XPS results. The FGO sheets with different functional groups exhibited different grafting abilities, and hydroxyl groups were proven to be the most reactive grafting sites for the in situ free radical grafting polymerization of polyacrylamide.

  12. The direct synthesis of organic-containing clays and thermal analysis of porphyrin-clay complexes

    SciTech Connect

    Carrado, K.A.; Anderson, K.B.; Grutkoski, P.S.

    1991-01-01

    Synthetic TMA-montmorillonites have now been made in conjunction with synthetic porphyrin-hectorites reported earlier. In order to help progress towards preparation of porphyrin-containing aluminosilicate clays, the thermal stability of porphyrin-clay systems has been examined in detail. Results from TGA and Py-GC-MS indicate that the porphyrin nucleus is extremely stable in the present of clay minerals. Substituents on the nucleus such as pyridinium or anilinium are, on the other hand, slightly destabilized. In addition, the presence of transition metals like Fe(III) in metalloporphyrins appears to catalyze decomposition of the porphyrin nucleus to some degree. The use of Py-GC-MS in conjunction with TGA results greatly clarified the assignment of weight loss peaks. 18 refs., 3 figs.

  13. Thermogravimetric and microscopic analysis of SiC/SiC materials with advanced interfaces

    SciTech Connect

    Windisch, C.F. Jr.; Jones, R.H.; Snead, L.L.

    1997-04-01

    The chemical stability of SiC/SiC composites with fiber/matrix interfaces consisting of multilayers of SiC/SiC and porous SiC have been evaluated using a thermal gravimetric analyzer (TGA). Previous evaluations of SiC/SiC composites with carbon interfacial layers demonstrated the layers are not chemically stable at goal use temperatures of 800-1100{degrees}C and O{sub 2} concentrations greater than about 1 ppm. No measureable mass change was observed for multilayer and porous SiC interfaces at 800-1100{degrees}C and O{sub 2} concentrations of 100 ppm to air; however, the total amount of oxidizable carbon is on the order of the sensitivity of the TGA. Further studies are in progress to evaluate the stability of these materials.

  14. Stress degradation studies of nelfinavir mesylate by Fourier transform infrared spectroscopy.

    PubMed

    Singh, Parul; Mehrotra, Ranjana; Bakhshi, A K

    2010-11-02

    Nelfinavir mesylate is the first nonpeptidic protease inhibitor available in pediatric formulation. In the present paper the stability of nelfinavir mesylate under different stress conditions is evaluated using Fourier transform infrared spectroscopy. The drug is subjected to thermal degradation, photodegradation, acid hydrolysis, base hydrolysis and oxidation as per ICH guidelines. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and high performance liquid chromatography (HPLC) are carried out to support the implementation of infrared spectroscopy for the stability studies of nelfinavir mesylate. Significant changes are observed in the IR spectra collected after exposing the drug to thermal radiations, acid and base hydrolysis and oxidative degradation. No change is observed in the spectra of the drug after exposing it to sunlight indicating the good photostability of nelfinavir mesylate. The results of infrared spectroscopy agree well with that of other complementary techniques as DSC, TGA, XRD and HPLC.

  15. Thermolysis of microalgae and duckweed in a CO₂-swept fixed-bed reactor: bio-oil yield and compositional effects.

    PubMed

    Campanella, Alejandrina; Muncrief, Rachel; Harold, Michael P; Griffith, David C; Whitton, Norman M; Weber, Robert S

    2012-04-01

    Microalgae and duckweed were grown and harvested over a three-month period in CO(2)-sparged helioreactors and open earthen ponds, respectively. The biomass feedstocks were thermolyzed in a thermogravimetric analyzer (TGA) and fixed-bed reactor to produce a fuel precursor coined "bioleum". Analysis of the thermolysis kinetics revealed an increase in the activation energy with heating rate for both aquatic species. Activation energies were lower than literature-reported values for lignocellulosics, corroborated by TGA thermolysis of pinewood. Thermolysis of microalgae resulted in higher bioleum and energy yields than for duckweed, reflecting differences in the biomass composition. The algal bioleum properties resemble those of crude petroleum except for higher nitrogen and oxygen content and acid number. Speciation identified 300+ compounds in the oil phase, with similar amounts of hydrocarbons and oxygenates, while acetic acid was the major species in the aqueous phase. The compounds were classified according to their degree of aromaticity, oxygenation, and nitrogenation.

  16. Characterization of urania vaporization with transpiration coupled thermogravimetry

    SciTech Connect

    McMurray, J. W.

    2015-12-05

    Determining equilibrium vapor pressures of materials is made easier by transpiration measurements. However, the traditional technique involves condensing the volatiles entrained in a carrier gas outside of the hot measurement zone. One potential problem is deposition en route to a cooled collector. Thermogravimetric analysis (TGA) can be used to measure in situ mass loss due to vaporization and therefore obviate the need to analyze the entire gas train due to premature plating of vapor species. Therefore, a transpiration coupled TGA technique was used to determine equilibrium pressures of UO3 gas over fluorite structure UO2+x and U3O8 at T = (1573 and 1773) K. Moreover, we compared to calculations from models and databases in the open literature. Our study gives clarity to the thermochemical data for UO3 gas and validates the mass loss transpiration method using thermogravimetry for determining equilibrium vapor pressures of non-stoichiometric oxides.

  17. Characterization of urania vaporization with transpiration coupled thermogravimetry

    DOE PAGES

    McMurray, J. W.

    2015-12-05

    Determining equilibrium vapor pressures of materials is made easier by transpiration measurements. However, the traditional technique involves condensing the volatiles entrained in a carrier gas outside of the hot measurement zone. One potential problem is deposition en route to a cooled collector. Thermogravimetric analysis (TGA) can be used to measure in situ mass loss due to vaporization and therefore obviate the need to analyze the entire gas train due to premature plating of vapor species. Therefore, a transpiration coupled TGA technique was used to determine equilibrium pressures of UO3 gas over fluorite structure UO2+x and U3O8 at T = (1573more » and 1773) K. Moreover, we compared to calculations from models and databases in the open literature. Our study gives clarity to the thermochemical data for UO3 gas and validates the mass loss transpiration method using thermogravimetry for determining equilibrium vapor pressures of non-stoichiometric oxides.« less

  18. Studying the effects of laccase treatment in a softwood dissolving pulp: cellulose reactivity and crystallinity.

    PubMed

    Quintana, Elisabet; Valls, Cristina; Barneto, Agustín G; Vidal, Teresa; Ariza, José; Roncero, M Blanca

    2015-03-30

    An enzymatic biobleaching sequence (LVAQPO) using a laccase from Trametes villosa in combination with violuric acid (VA) and then followed by a pressurized hydrogen peroxide treatment (PO) was developed and found to give high bleaching properties and meet dissolving pulp requirements: high brightness, low content of hemicellulose, satisfactory pulp reactivity, no significant cellulose degradation manifested by α-cellulose and HPLC, and brightness stability against moist heat ageing. The incorporation of a laccase-mediator system (LMS) to bleach sulphite pulps can be a good alternative to traditional bleaching processes since thermogravimetric analysis (TGA) showed that the laccase treatment prevented the adverse effect of hydrogen peroxide on fibre surface as observed during a conventional hydrogen peroxide bleaching treatment (PO). Although VA exhibited the best results in terms of bleaching properties, the performance of natural mediators, such as p-coumaric acid and syringaldehyde, was discussed in relation to changes in cellulose surface detected by TGA.

  19. Abnormal origin of the right subclavian artery from the right pulmonary artery in a patient with D-transposition of the great vessels and left juxtaposition of the right atrial appendage: an unusual anatomical variant.

    PubMed

    Mosieri, Jackmerry; Chintala, Kavitha; Delius, Ralph E; Walters, Henry L; Hakimi, Mehdi

    2004-01-01

    Isolation of the left subclavian artery (LSCA) or its anomalous origin from the pulmonary artery (PA) has been documented in several cases, especially in association with a right-sided aortic arch. Similar anomalies involving the right subclavian artery (RSCA) are less frequent. Anomalous origin of the RSCA from the PA in association with D-transposition of the great arteries (D-TGA) is exceedingly rare and only two cases have been reported so far. We present here, a case of aberrant origin of the RSCA from the right PA in a patient with D-TGA, in whom the diagnosis was rendered difficult due to the partial occlusion of the intervening ductus arteriosus (DA). We discuss the embryological basis of this anomaly and review its clinical and surgical implications.

  20. Structural and Thermal Characterization of Ti+O Ion Implanted UltraHigh Molecular Weight Polyethylene (UHMWPE)

    SciTech Connect

    Oztarhan, A.; Urkac, E. Sokullu; Kaya, N.; Tihminlioglu, F.; Ila, D.; Chhay, B.; Muntele, C.; Budak, S.; Oks, E.; Nikolaev, A.

    2009-03-10

    In this work, Metal-Gas Hybrid Ion Implantation technique was used as a tool for the surface modification of Ultra High Molecular Weight Polyethylene (UHMWPE). Samples were Ti+O ion implanted by using Metal-Vapour Vacuum Arc (MEVVA) ion implanter to a fluence of 5x10{sup 16} ion/cm{sup 2} for each species and extraction voltage of 30 kV. Untreated and surface treated samples were investigated by Rutherford Back Scattering (RBS) Spectrometry, Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy, Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Results indicate that Ti+O ion implantation can be applied on UHMWPE surfaces successfully. ATR-FTIR spectra indicate that the C-H concentration on the surface decreased after Ti+O implantation. Thermal characterization with TGA and DSC shows that polymeric decomposition temperature is shifted after ion implantation.

  1. A rapid and sensitive assay for determination of doxycycline using thioglycolic acid-capped cadmium telluride quantum dots

    NASA Astrophysics Data System (ADS)

    Tashkhourian, Javad; Absalan, Ghodratollah; Jafari, Marzieh; Zare, Saber

    2016-01-01

    A rapid, simple and inexpensive spectrofluorimetric sensor for determination of doxycycline based on its interaction with thioglycolic acid-capped cadmium telluride quantum dots (TGA/CdTe QDs) has been developed. Under the optimum experimental conditions, the sensor exhibited a fast response time of <10 s. The results revealed that doxycycline could quench the fluorescence of TGA/CdTe QDs via electron transfer from the QDs to doxycycline through a dynamic quenching mechanism. The sensor permitted determination of doxycycline in a concentration range of 1.9 × 10-6-6.1 × 10-5 mol L-1 with a detection limit of 1.1 × 10-7 mol L-1. The sensor was applied for determination of doxycycline in honey and human serum samples.

  2. Synthesis of raloxifene-chitosan conjugate: A novel chitosan derivative as a potential targeting vehicle.

    PubMed

    Samadi, Fatemeh Yazdi; Mohammadi, Zohreh; Yousefi, Maryam; Majdejabbari, Sara

    2016-01-01

    Chitosan is a biocompatible, non-toxic and biodegradable biopolymer. Due to the presence of functional groups on its surface, it can be modified and used as a carrier in targeted drug/gene delivery systems. In this study, raloxifene (a selective estrogen receptor ligand) was conjugated to chitosan using different methods. The conjugates were investigated by means of FTIR, TGA and physical properties assessments. Cell viability was evaluated by XTT assay. FTIR and TGA results confirmed that the conjugation between chitosan and raloxifene occurred more efficiently when trimethyl chitosan in the presence of triethylamine and excess amount of linker was used. XTT assay on MCF-7 cell line illustrated that more than 80% of cells were viable after 24h exposure to selected molecules. These findings confirm that the conjugation of raloxifene-chitosan can occur successfully using special synthesis condition and this novel chitosan derivative can be introduced as a potential drug/gene targeting agent.

  3. Structural phase transitions and adduct release in calcium borohydride

    SciTech Connect

    Paolone, A.; Palumbo, O.; Rispoli, P.; Miriametro, A.; Cantelli, R.; Luedtke, A.; Rönnebro, E.; Chandra, D.

    2011-09-01

    Ca(BH4)2 compounds were investigated above room temperature by anelastic spectroscopy (AS) and concomitant measurements of thermogravimetry and mass spectrometry (TGA/MS). Both AS and TGA/MS indicate that even after a thermal treatment at 125 °C for 20 h, a non-negligible residual of THF adduct is still present in the sample, which can be removed on a subsequent thermal treatment at temperatures lower than 250 °C. Above 250 °C dehydrogenation takes place. Moreover, AS sensitively detects the occurrence of the α → α’ structural phase transition around 180 °C, and the α’ → β transformation, which is completed around 330 °C. Finally, we also show that both transitions are irreversible and are not accompanied by a latent heat.

  4. A neuroprotective role for microglia in prion diseases

    PubMed Central

    Herrmann, Uli S.; Falsig, Jeppe; Abakumova, Irina; Nuvolone, Mario; Schwarz, Petra; Frauenknecht, Katrin; Rushing, Elisabeth J.

    2016-01-01

    Microglial activation is a hallmark of most neurodegenerative disorders, and is particularly conspicuous in prion diseases. However, the role of microglia, which function as both primary immune effector cells and professional phagocytes in the central nervous system, remains contentious in the context of neurodegeneration. Here, we evaluated the effect of microglial depletion/deficiency on prion pathogenesis. We found that ganciclovir-mediated microglial ablation on tga20/CD11b-thymidine kinase of Herpes simplex virus (HSVTK) cerebellar organotypic cultured slices markedly aggravated prion-induced neurotoxicity. A similar deterioration of disease was recapitulated in in vivo microglial depletion in prion-infected tga20/CD11b-HSVTK mice. Additionally, deficiency of microglia in interleukin 34 knockout (IL34−/−) mice again resulted in significantly augmented proteinase K–resistant prion protein deposition and accelerated prion disease progression. These results provide unambiguous evidence for a general protective role of microglia in prion pathogenesis. PMID:27185853

  5. A facile approach for shape selective synthesis of rhodium nanostructures and conductivity studies

    SciTech Connect

    Sathe, Bhaskar R.

    2012-12-15

    Shape selective synthesis of Rh nanostructures has been demonstrated with the help of a single step chemical vapor deposition, where different shapes like cubes at 500 Degree-Sign C, pyramids and hexagons at 500 Degree-Sign C, 700 Degree-Sign C and 900 Degree-Sign C respectively have been obtained as a function of temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and four probe conductivity measurements were used to study the morphology, crystallinity and phase purity of the structures. The conductivity values for as synthesised nanostructures have been obtained in the range of 2-7 kS/cm{sup 2}. On the basis of the experimental results, from TGA and XPS studies possible mechanistic pathway for the evolution of Rh nanostructures was discussed.

  6. Pyrolysis kinetics of hazelnut husk using thermogravimetric analysis.

    PubMed

    Ceylan, Selim; Topçu, Yıldıray

    2014-03-01

    This study aims at investigating physicochemical properties and pyrolysis kinetics of hazelnut husk, an abundant agricultural waste in Turkey. The physicochemical properties were determined by bomb calorimeter, elemental analysis and FT-IR spectroscopy. Physicochemical analysis results showed that hazelnut husk has a high calorimetric value and high volatile matter content. Pyrolysis experiments were carried out in a thermogravimetric analyzer under inert conditions and operated at different heating rates (5, 10, 20°C/min). Three different kinetic models, the iso-conversional Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) models and Coats-Redfern method were applied on TGA data of hazelnut husk to calculate the kinetic parameters including activation energy, pre-exponential factor and reaction order. Simulation of hazelnut husk pyrolysis using data obtained from TGA analysis showed good agreement with experimental data. Combining with physicochemical properties, it was concluded that this biomass can become useful source of energy or chemicals.

  7. Oxygen carrier development for chemical looping combustion of coal derived synthesis gas

    SciTech Connect

    Siriwardane, R.V.; Chaudhari, K.; Zinn, A.N.; Simonyi, T.; Robinson, Clark; Poston, J.A.

    2006-09-01

    In the present work, NETL researchers have studied chemical looping combustion (CLC) with an oxygen carrier NiO/bentonite (60 wt.% NiO) for the IGCC systems utilizing simulated synthesis gas. Multi cycle CLC was conducted with NiO/Bentonite in TGA at atmospheric pressure and in a high pressure reactor in a temperature range between 700-900°C. Global reaction rates of reduction and oxidation as a function of conversion were calculated for all oxidation-reduction cycles utilizing the TGA data. The effect of particle size of the oxygen carrier on CLC was studied for the size between 20-200 mesh. The multi cycle CLC tests conducted in a high pressure packed bed flow reactor indicated constant total production of CO2 from fuel gas at 800°C and 900°C and full consumption of hydrogen during the reaction.

  8. Preparing cationic cotton linter cellulose with high substitution degree by ultrasonic treatment.

    PubMed

    Zhang, Fulong; Pang, Zhiqiang; Dong, Cuihua; Liu, Zong

    2015-11-05

    As an important cellulose derivative, cationic cellulose has becoming an attractive material. However, it remains challenging to produce cationic cellulose with high substitute degree. In this paper, we successfully increased the substitute degree of cationic cellulose by introducing ultrasonic treatment, which efficiently breaks hydrogen bonds of the chemical structure of cationic cellulose. Properties of cationic cellulose were studied by scanning electron spectroscope (SEM), contact angle, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Experimental results show that the cationic cellulose has rougher surface and lower crystallinity degree as compared to the original sample. TGA analysis verifies that the thermostability of CLC decreases after the cationic modification. The residual of the cationic cellulose (25 wt%) after pyrolysis increases significantly as compared to that of the original cellulose (15 wt%).

  9. Catalytic pyrolysis of tobacco rob: kinetic study and fuel gas produced.

    PubMed

    Yang, Yi; Li, Tan; Jin, Shiping; Lin, Yixin; Yang, Haiping

    2011-12-01

    The pyrolysis kinetics of tobacco rob (TR) was investigated using thermogravimetric analysis (TGA) under inert atmosphere, adding chemicals (dolomite and NiO) as catalysts by catalytic-mixing method. The TGA results showed that mass loss and mass loss rates were affected by catalysts. The conversion rates increased while the activation energy decreased. Moreover, the thermal decomposition behaviors of TR were studied in the fixed-bed reactor using dolomite and NiO/γ-Al2O3 as catalysts by catalyst-bed method. A series of experiments had been performed to explore the effects of catalysts, and reaction temperature on the composition and yield of fuel gas. The experiments demonstrated that the catalysts had a high activity of cracking tar and hydrocarbons, as well as yielding a high fuel gas production. For both methods, dolomite and NiO revealed better catalytic performance as a view of enhancing conversion rates and increasing product gas yield.

  10. KINETIC STUDY OF COAL AND BIOMASS CO-PYROLYSIS USING THERMOGRAVIMETRY

    SciTech Connect

    Wang, Ping; Hedges, Sheila; Chaudharib, Kiran; Turtonb, Richard

    2013-10-29

    The objectives of this study are to investigate thermal behavior of coal and biomass blends in inert gas environment at low heating rates and to develop a simplified kinetic model using model fitting techniques based on TGA experimental data. Differences in thermal behavior and reactivity in co-pyrolysis of Powder River Basin (PRB) sub-bituminous coal and pelletized southern yellow pine wood sawdust blends at low heating rates are observed. Coal/wood blends have higher reactivity compared to coal alone in the lower temperature due to the high volatile matter content of wood. As heating rates increase, weight loss rates increase. The experiment data obtained from TGA has a better fit with proposed two step first order reactions model compared single first order reaction model.

  11. Low temperature synthesis of fluorescent ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Khan, Yaqoob; Durrani, S. K.; Mehmood, Mazhar; Ahmad, Jamil; Khan, M. Riaz; Firdous, Shamraz

    2010-12-01

    Fluorescent ZnO nanoparticles have been prepared by mixing aqueous solutions of zinc nitrate and ammonium carbonate in the presence of a non-ionic surfactant, Tween-80. Increased concentrations of the surfactant were found to affect both the morphology and purity of the synthesized ZnO nanoparticles. XRD, SEM, FTIR, TGA and Confocal laser scanning microscopy were employed to characterize the as-prepared samples. ZnO nanoparticles ranging in particle size from 11 to 15 nm were formed at the reaction temperature of 70-80 °C. The results of FTIR and TGA analysis indicate the self assembly of Tween molecules on the surface of ZnO nanoparticles. A bright emission in the visible region from the as-prepared ZnO nanoparticles was recorded using confocal laser scanning microscopy. This property of the as-prepared nanoparticles may find potential application in bio-imaging.

  12. A Novel Tumor Antigen and Foxp3 Dual Targeting Tumor Cell Vaccine Enhances the Immunotherapy in a Murine Model of Renal Cell Carcinoma

    DTIC Science & Technology

    2015-12-01

    clone BM8), CD206 (clone C068C2), Arg 1 (polyclonal antibody; R&D Systems; Cat : IC5868A), iNOS Tasquinimod Enhances Cancer Immunotherapies...actin_fw50-ATGCTC CCC GGG CTG TAT- 30, b-actin_rev 50- CAT AGG AGT CCT TCT GAC CCA TTC-30; Ywhaz_fw 50-AAC AGC TTT CGA TGA AGC CAT -30 Ywhaz_rev 50-TGG...GT-30, Arg-1_rev 50-CTG GTT GTC AGG GGA GTG TT-30; iNOS_fw 50-TGG TGG TGA CAA GCA CAT TT-30, iNOS_rev 50- AAG GCC AAA CAC AGC ATA CC-30; Cxcl9_fw 50

  13. Spectroscopic characterization of recently excavated archaeological potsherds from Tamilnadu, India with multi-analytical approach.

    PubMed

    Raja Annamalai, G; Ravisankar, R; Rajalakshmi, A; Chandrasekaran, A; Rajan, K

    2014-12-10

    A combined analytical study of potsherds excavated from different archaeological sites of Tamilnadu (Kavalapatti, Nattapuraki and Thamaraikulam villages), India are analyzed by spectroscopic techniques such as FTIR, X-ray diffraction, thermogravimetric analysis (TGA) and Scanning Electron Microscope (SEM) coupled with Energy Dispersive Spectrometer (EDS). FTIR and XRD techniques have been attempted to characterize the mineralogical composition, firing temperature and firing conditions of the archaeological potsherds. Thermogravimetric analysis (TGA) is the complementary study to estimate the firing temperature from characteristic thermal reactions in potsherds under controlled firing in inert gas atmosphere. Further, Scanning Electron Microscopy (SEM) equipped and coupled with an Energy Dispersive Spectrometer (EDS) to analyze internal morphology and chemical composition of the potsherds was used. From the results of the above techniques, the firing temperatures of potsherds were found to be greater than 650°C.

  14. The Surface Structure and Thermal Properties of Novel Polymer Composite Films Based on Partially Phosphorylated Poly(vinyl alcohol) with Aluminum Phosphate

    PubMed Central

    Mohamed Saat, Asmalina

    2014-01-01

    Partially phosphorylated polyvinyl alcohol (PPVA) with aluminum phosphate (ALPO4) composites was synthesized by solution casting technique to produce (PPVA)100−y − (ALPO4)y (y = 0, 1, and 2). The surface structure and thermal properties of the films were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The results showed that the films have higher thermal stability with strong bonding between PPVA and ALPO4. PMID:25506069

  15. C-104 Solid Phase Characterization of Sample 4C-13-1 From Tank 241-C-104 Closure Sampling Event

    SciTech Connect

    Cooke, Gary A.; Pestovich, John A.

    2013-06-12

    One solid grab sample from closure sampling in Riser 7 of tank 214-C-I04 (C-I04) was examined to determine the solid phases that were present. The sample was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The purpose of this analysis was to see if the presence of hydrated phases could provide a possible explanation for the high moisture content obtained from thermogravimetric analysis (TGA).

  16. Using 4D Cardiovascular Magnetic Resonance Imaging to Validate Computational Fluid Dynamics: A Case Study.

    PubMed

    Biglino, Giovanni; Cosentino, Daria; Steeden, Jennifer A; De Nova, Lorenzo; Castelli, Matteo; Ntsinjana, Hopewell; Pennati, Giancarlo; Taylor, Andrew M; Schievano, Silvia

    2015-01-01

    Computational fluid dynamics (CFD) can have a complementary predictive role alongside the exquisite visualization capabilities of 4D cardiovascular magnetic resonance (CMR) imaging. In order to exploit these capabilities (e.g., for decision-making), it is necessary to validate computational models against real world data. In this study, we sought to acquire 4D CMR flow data in a controllable, experimental setup and use these data to validate a corresponding computational model. We applied this paradigm to a case of congenital heart disease, namely, transposition of the great arteries (TGA) repaired with arterial switch operation. For this purpose, a mock circulatory loop compatible with the CMR environment was constructed and two detailed aortic 3D models (i.e., one TGA case and one normal aortic anatomy) were tested under realistic hemodynamic conditions, acquiring 4D CMR flow. The same 3D domains were used for multi-scale CFD simulations, whereby the remainder of the mock circulatory system was appropriately summarized with a lumped parameter network. Boundary conditions of the simulations mirrored those measured in vitro. Results showed a very good quantitative agreement between experimental and computational models in terms of pressure (overall maximum % error = 4.4% aortic pressure in the control anatomy) and flow distribution data (overall maximum % error = 3.6% at the subclavian artery outlet of the TGA model). Very good qualitative agreement could also be appreciated in terms of streamlines, throughout the cardiac cycle. Additionally, velocity vectors in the ascending aorta revealed less symmetrical flow in the TGA model, which also exhibited higher wall shear stress in the anterior ascending aorta.

  17. Oxidative stability of LARC (tm)-TPI films

    NASA Technical Reports Server (NTRS)

    Hinkley, Jeffrey A.

    1992-01-01

    The oxidative aging of 50-micron-thick films of LARC-TPI was studied using conventional thermogravimetric techniques and measurements of plane-stress fracture toughness. It was shown that at high temperature, most of the toughness loss occurred very early relative to the weight loss. The difficulties of interpreting TGA results in this regime and the problems of extrapolations to long times are discussed.

  18. Combining piracetam and lithium salts: ionic co-crystals and co-drugs?

    PubMed

    Braga, Dario; Grepioni, Fabrizia; Maini, Lucia; Capucci, Davide; Nanna, Saverio; Wouters, Johan; Aerts, Luc; Quéré, Luc

    2012-08-25

    Mechanochemical reaction of solid piracetam with the inorganic salts LiCl and LiBr yields ionic co-crystals which are also co-drugs, characterized by markedly different thermal properties with respect to pure components, also depending on the method for preparation and/or conditions of measurements; single crystal and powder X-ray diffraction at variable temperatures, DSC, TGA, hot stage microscopy (HSM) and intrinsic dissolution rate have been used to fully characterize the solid products.

  19. Thermal properties of transition metals doped (A: Co, Ni and Cu) BiFe0.9A0.1O3

    NASA Astrophysics Data System (ADS)

    Parveen, Azra; Agrawal, Shraddha; Azam, Ameer

    2016-05-01

    The synthesis of pure and transition metals (Co, Ni and Cu) doped BiFeO3nanoparticles, a promising G-type antiferromagnetic material have been done by auto combustion method using citric acid as a fuel. Microstructural analyses were done by XRD and FTIR. The thermal stability of the sample was determined by thermo gravimetric analysis (TGA) and heat flow rate was plotted by differential scanning calorimetric (DSC).

  20. Chemistry of Processible Acetylene-Terminated Imides

    DTIC Science & Technology

    1983-08-01

    and consultations in DSC -TGA analyses, FT-IR spectroscopy, NMR spectrometry, and HPLC-GPC analyses were provided by Mr. Philip G. Magallanes, Mr. Herman...11 Differential Scanning Calorimetry ( DSC ) for HR600P (Lot M1126-1) ........ 15 12 Differential Scanning Calorimetry ( DSC ) Curves for Thermid 600 and H...17 14 Gel Permeation Chromatogram for HR605P (Lot M1126-33A) .............. 18 15 Differential Scanning Calorimetry ( DSC ) for HR602P Oligomer (M1126-42

  1. Factor XII full and partial null in rat confers robust antithrombotic efficacy with no bleeding.

    PubMed

    Cai, Tian-Quan; Wu, Weizhen; Shin, Myung K; Xu, Yiming; Jochnowitz, Nina; Zhou, Yuchen; Hoos, Lizbeth; Bentley, Ross; Strapps, Walter; Thankappan, Anil; Metzger, Joseph M; Ogletree, Martin L; Tadin-Strapps, Marija; Seiffert, Dietmar A; Chen, Zhu

    2015-12-01

    This report aims at exploring quantitatively the relationship between FXII inhibition and thromboprotection. FXII full and partial null in rats were established via zinc finger nuclease-mediated knockout and siRNA-mediated knockdown, respectively. The rats were subsequently characterized in thrombosis and hemostasis models. Knockout rats exhibited complete thromboprotection in both the arteriovenous shunt model (∼100% clot weight reduction) and the FeCl3-induced arterial thrombosis model (no reduction in blood flow), without any increase in cuticle bleeding time compared with wild-type control rats. Ex-vivo aPTT and the ellagic acid-triggered thrombin generation assay (TGA) exhibited anticoagulant changes. In contrast, ex-vivo PT or high tissue factor-triggered TGA was indistinguishable from control. Rats receiving single doses (0, 0.01, 0.03, 0.1, 0.3, 1 mg/kg) of FXII siRNA exhibited dose-dependent knockdown in liver FXII mRNA and plasma FXII protein (95 and 99%, respectively, at 1 mg/kg) at day 7 post dosing. FXII knockdown was associated with dose-dependent thromboprotection (maximal efficacy achieved with 1 mg/kg in both models) and negligible change in cuticle bleeding times. Ex-vivo TGA triggered with low-level (0.5 μmol/l) ellagic acid tracked best with the knockdown levels and efficacy. Our findings confirm and extend literature reports of an attractive benefit-to-risk profile of targeting FXII for antithrombotic therapies. Titrating of FXII is instructive for its pharmacological inhibition. The knockout rat is valuable for evaluating both mechanism-based safety concerns and off-target effects of FXII(a) inhibitors. Detailed TGA analyses will inform on optimal trigger conditions in studying pharmacodynamic effects of FXII(a) inhibition.

  2. Using 4D Cardiovascular Magnetic Resonance Imaging to Validate Computational Fluid Dynamics: A Case Study

    PubMed Central

    Biglino, Giovanni; Cosentino, Daria; Steeden, Jennifer A.; De Nova, Lorenzo; Castelli, Matteo; Ntsinjana, Hopewell; Pennati, Giancarlo; Taylor, Andrew M.; Schievano, Silvia

    2015-01-01

    Computational fluid dynamics (CFD) can have a complementary predictive role alongside the exquisite visualization capabilities of 4D cardiovascular magnetic resonance (CMR) imaging. In order to exploit these capabilities (e.g., for decision-making), it is necessary to validate computational models against real world data. In this study, we sought to acquire 4D CMR flow data in a controllable, experimental setup and use these data to validate a corresponding computational model. We applied this paradigm to a case of congenital heart disease, namely, transposition of the great arteries (TGA) repaired with arterial switch operation. For this purpose, a mock circulatory loop compatible with the CMR environment was constructed and two detailed aortic 3D models (i.e., one TGA case and one normal aortic anatomy) were tested under realistic hemodynamic conditions, acquiring 4D CMR flow. The same 3D domains were used for multi-scale CFD simulations, whereby the remainder of the mock circulatory system was appropriately summarized with a lumped parameter network. Boundary conditions of the simulations mirrored those measured in vitro. Results showed a very good quantitative agreement between experimental and computational models in terms of pressure (overall maximum % error = 4.4% aortic pressure in the control anatomy) and flow distribution data (overall maximum % error = 3.6% at the subclavian artery outlet of the TGA model). Very good qualitative agreement could also be appreciated in terms of streamlines, throughout the cardiac cycle. Additionally, velocity vectors in the ascending aorta revealed less symmetrical flow in the TGA model, which also exhibited higher wall shear stress in the anterior ascending aorta. PMID:26697416

  3. Characterization of a neutral and thermostable glucoamylase from the thermophilic mold Thermomucor indicae-seudaticae: activity, stability, and structural correlation.

    PubMed

    Kumar, Pardeep; Islam, Asimul; Ahmad, Faizan; Satyanarayana, T

    2010-03-01

    Glucoamylase from the thermophilic mold Thermomucor indicae-seudaticae was purified by anion exchange and gel filtration chromatographic techniques using a fast protein liquid chromatographic system. The structure and thermal stability of this unique 'thermostable and neutral glucoamylase' were analyzed by circular dichroism (CD). T. indicae-seudaticae glucoamylase (TGA) contained typical aromatic amino acid (tryptophan/tyrosine) fingerprints in its tertiary structure. Analysis of the far-UV CD spectrum at pH 7.0 and 25 degrees Celsius revealed the presence of 45% alpha-helix, 43% beta-sheet, and 12% remaining structures. The alpha-helix content was highest at pH 7.0, where glucoamylase is optimally active. This observation points towards the possible (alpha/alpha)(6) barrel catalytic domain in TGA, as reported in microbial glucoamylases. Thermal denaturation curves of the pure protein at different pH values revealed maximum stability at pH 7.0, where no change in the secondary structure was observed upon heating in the temperature range between 20 degrees Celsius and 60 degrees Celsius. The observed midpoint of thermal denaturation (T (m)) of glucoamylase at pH 7.0 was 67.1 degrees Celsius, which decreased on either sides of this pH. Thermostability of TGA enhanced in the presence of starch (0.1%) as no transition curve was obtained in the temperature range between 20 degrees Celsius and 85 degrees Celsius. The only product of TGA action on starch was glucose, and it did not exhibit transglycosylation activity even at 40% glucose that can also be considered as an advantage during starch saccharification.

  4. Oxidation Effects on the Mechanical Properties of SiC Fiber-Reinforced Reaction-Bonded Silicon Nitride Matrix Composites

    DTIC Science & Technology

    1989-11-01

    fibers in the fiber mat and the other polymer for preparing pliable silicon cloth. The volume fraction of fiber in the final composite was controlled by...and mechanical properties for the composite are given in Table I. (2) Specimen Preparation and Testing The specimens for thermal stability and for...thermogravimetric analysis (TGA) were prepared from the composite panels by cutting and grinding them with a diamond impregnated abrasive wheel. Nominal

  5. Persistent institutional difficulties in surgery for transposition of the great arteries in guatemala: analysis with the aristotle basic and comprehensive scores.

    PubMed

    Leon-Wyss, Juan; Lo Rito, Mauro; Barnoya, Joaquin; Castañeda, Aldo R

    2011-07-01

    Background. Neonates with complex congenital cardiac lesions are largely inadequately managed in Guatemala. Methods. Between 1997 and 2009, 79 patients who underwent operations for transposition of the great arteries were identified; 51 (63.3%) had an arterial switch operation (ASO) and 28 (36%) an atrial switch operation (ATSO). The Aristotle Basic Complexity score (ABC score) and the Aristotle Comprehensive Complexity score (ACC score) have been used to aid in the evaluation of quality of care associated with pediatric cardiac surgery by adjusting for operative complexity. Results. In-hospital mortality was 47% for the ASO and 25% for the ATSO group; 36.7% were beyond 1 month of age and many exhibited increased preoperative risk factors. The mean ABC score was 9.75 ± 0.89 and the ACC score was 12.12 ± 2.7, with a mean 2.36-point increase (P < .05). Comparing survivors and nonsurvivors with both scores, significant differences were identified (ABC: P < .04 and ACC: P < .02). Conclusion. During this 13-year period, a low volume of surgery for transposition of the great arteries (TGA) was performed at our institution with a relatively high surgical mortality. Many patients with TGA in Guatemala are either never referred for surgery or referred late. Strategies to improve outcomes for neonates with TGA in Guatemala must include increases in early diagnosis countrywide and prompt referral to our unit. Based on the larger number of neonates with TGA that would be referred to our center, we anticipate that this strategy should substantially improve surgical outcomes and favor overall team-related skills.

  6. The role of thermal analysis techniques in the in-situ combustion process

    SciTech Connect

    Jka, K.N.; Verkoczy, B.

    1984-04-01

    Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) studies were conducted on two Lloydminster heavy oil cores, extracted oil and mineral matter. The order of reaction was adjusted to best fit the data in nonisothermal kinetic analysis. The values of the order of reaction used and estimated activation energies, preexponential factors and rate constants for overall reactions occurring in appropriate temperature regimes are listed. A general schematic of the thermal processes, such as evaporation, distillation, thermolysis, low temperature oxidation, thermal cracking, combustion, coking, polymerization and thermal alteration of mineral matter, is depicted. The fuel contents in the core samples were determined from the TGA weight loss curves. The data generated by DSC and TGA experiments were used to calculate enthalpy values and ignition temperatures. Data suggests that heat generated by LTO reactions is significant during in situ combustion. Thermal alteration of the mineral matter at 600/sup 0/ and 900/sup 0/C was significant. The percentage of fine particles, <2..mu.., doubled at 600/sup 0/ and 900/sup 0/C compared to the mineral extracted at 100/sup 0/C. Although kaolinite constituted 65% of the fine particles in the extracted sand, it was not detected when the sand was heated at 600/sup 0/ or 900/sup 0/C. These results indicate potential production problems resulting from the migration of fine particles. The data obtained from the two reservoirs studied suggest that swelling of clays during wet combustion may not be sufficient to have a deleterious effect on air/water injectivity. It is apparent that the results generated by TGA/DSC experiments are complementary to those obtained by combustion tube tests and provide the kinetic, thermal and mineralogical data required for numerical simulation, planning and design of an in situ combustion project.

  7. Radiation-grafting of ethylene glycol dimethacrylate (EGDMA) and glycidyl methacrylate (GMA) onto silicone rubber

    NASA Astrophysics Data System (ADS)

    Flores-Rojas, G. G.; Bucio, E.

    2016-10-01

    Silicone rubber (SR) was modified with a graft of ethylene glycol dimethacrylate (EGDMA) and glycidyl methacrylate (GMA) using either gamma-radiation or azobisisobutyronitrile (AIBN). The graft efficiency was evaluated as a function of monomer concentration, absorbed dose, reaction temperature, and concentration of AIBN. The hydrophilicity of the grafted films was measured by contact angle and their equilibrium swelling time in ethanol. Additional characterization by infrared (FTIR-ATR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is also reported.

  8. High Temperature Epoxy Nanocomposites for Aerospace Applications

    DTIC Science & Technology

    2009-06-10

    weak molecular interaction between non-polar alkyl chain of ammonium modified clay and polar group of epoxy resin. This was confirmed by the X- ray...polymer matrix. Several functionalized imidazolium clays , functionalized anionic clays , and silylated apophylites were synthesized and characterized by...XRD and TGA. Thermal studies of functionalized clay have shown that the onset decomposition temperature of imidazolium functionalized clay (>325oC

  9. Identification of S-(carboxymethyl)-L-cysteine and thiodiglycolic acid, urinary metabolites of 2,2'-bis-(chloroethyl)-ether in the rat.

    PubMed

    Müller, G; Norpoth, K; Eckard, R

    1979-09-01

    S-(carboxymethyl)-L-cysteine (CMC) and thiodiglycollic acid (TGA) were identified by gas chromatographic-mass spectrometric measurements in the urine of rats after intraperitoneal injections of 2,2'-bis-(chloroethyl)-ether (BCEE). It is therefore probable that BCEE is O-dealkylated by a mixed-function oxidation. The hepatocarcinogenic effect of BCEE may be explained by the liberation of chloroacetaldehyde in vivo.

  10. Comprehensive and quantitative mapping of RNA-protein interactions across a transcribed eukaryotic genome.

    PubMed

    She, Richard; Chakravarty, Anupam K; Layton, Curtis J; Chircus, Lauren M; Andreasson, Johan O L; Damaraju, Nandita; McMahon, Peter L; Buenrostro, Jason D; Jarosz, Daniel F; Greenleaf, William J

    2017-04-04

    RNA-binding proteins (RBPs) control the fate of nearly every transcript in a cell. However, no existing approach for studying these posttranscriptional gene regulators combines transcriptome-wide throughput and biophysical precision. Here, we describe an assay that accomplishes this. Using commonly available hardware, we built a customizable, open-source platform that leverages the inherent throughput of Illumina technology for direct biophysical measurements. We used the platform to quantitatively measure the binding affinity of the prototypical RBP Vts1 for every transcript in the Saccharomyces cerevisiae genome. The scale and precision of these measurements revealed many previously unknown features of this well-studied RBP. Our transcribed genome array (TGA) assayed both rare and abundant transcripts with equivalent proficiency, revealing hundreds of low-abundance targets missed by previous approaches. These targets regulated diverse biological processes including nutrient sensing and the DNA damage response, and implicated Vts1 in de novo gene "birth." TGA provided single-nucleotide resolution for each binding site and delineated a highly specific sequence and structure motif for Vts1 binding. Changes in transcript levels in vts1Δ cells established the regulatory function of these binding sites. The impact of Vts1 on transcript abundance was largely independent of where it bound within an mRNA, challenging prevailing assumptions about how this RBP drives RNA degradation. TGA thus enables a quantitative description of the relationship between variant RNA structures, affinity, and in vivo phenotype on a transcriptome-wide scale. We anticipate that TGA will provide similarly comprehensive and quantitative insights into the function of virtually any RBP.

  11. Laboratory Evaluation of Expedient Low-Temperature Admixtures for Runway Craters in Cold Weather

    DTIC Science & Technology

    2014-10-01

    Sulfur Trioxide Sug Cane Sugar TGA Thermogravimetry Analysis UCS Unconfined Compressive Strength USACE US Army Corps of Engineers w/c Water...applications, including asphalt surface and sub-surface ex- pedient repair, our research explored improvements to the Utility Fill at near- and sub-freezing... sulfur trioxide (SO3) and aluminum oxide (Al2O3) compositions present in both materials along with the relatively low calcium oxide content (typically

  12. Midterm results after arterial switch operation for transposition of the great arteries: a single centre experience

    PubMed Central

    2012-01-01

    Background The arterial switch operation (ASO) has become the surgical approach of choice for d-transposition of the great arteries (d-TGA). There is, however an increased incidence of midterm and longterm adverse sequelae in some survivors. In order to evaluate operative risk and midterm outcome in this population, we reviewed patients who underwent ASO for TGA at our centre. Methods In this retrospective study 52 consecutive patients with TGA who underwent ASO between 04/1991 and 12/1999 were included. To analyze the predictors for mortality and adverse events (coronary stenoses, distortion of the pulmonary arteries, dilatation of the neoaortic root, and aortic regurgitation), a multivariate analysis was performed. The follow-up time was ranged from 1–10 years (mean 5 years, cumulative 260 patient-years). Results All over mortality rate was 15.4% and was only observed in the early postoperative period till 1994. The predictors for poor operative survival were low APGAR-score, older age at surgery, and necessity of associated surgical procedures. Late re-operations were necessary in 6 patients (13.6%) and included a pulmonary artery patch enlargement due to supravalvular stenosis (n = 3), coronary revascularisation due to coronary stenosis in a coronary anatomy type E, aortic valve replacement due to neoaortic valve regurgitation (n = 2), and patch-plasty of a pulmonary vein due to obstruction (n = 1). The dilatation of neoaortic root was not observed in the follow up. Conclusions ASO remains the procedure of choice for TGA with acceptable early and late outcome in terms of overall survival and freedom of reoperation. Although ASO is often complex and may be associated with morbidity, most patients survived without major complications even in a small centre. PMID:22958234

  13. D-TRANSPOSITION OF THE GREAT ARTERIES: Hot Topics in the Current Era of the Arterial Switch Operation

    PubMed Central

    Villafañe, Juan; Lantin-Hermoso, M. Regina; Bhatt, Ami B.; Tweddell, James S.; Geva, Tal; Nathan, Meena; Elliott, Martin J.; Vetter, Victoria L.; Paridon, Stephen M.; Kochilas, Lazaros; Jenkins, Kathy J.; Beekman, Robert H.; Wernovsky, Gil; Towbin, Jeffrey A.

    2015-01-01

    Objectives This paper aims to update clinicians on “Hot Topics” in the management of patients with d-transposition of the great arteries (D-TGA) in the current surgical era. Background The arterial switch operation (ASO) has replaced atrial switch procedures for D-TGA and 90% of patients now reach adulthood. Methods The Adult Congenital and Pediatric Cardiology Council (ACPC) of the American College of Cardiology assembled a team of experts to summarize current knowledge on genetics, prenatal diagnosis, surgical timing, balloon atrial septostomy (BAS), prostaglandin therapy (PGE), intraoperative techniques, imaging, coronary obstruction, arrhythmias, sudden death, aortic dilation and regurgitation (AR), neurodevelopmental (ND) issues and lifelong care of D-TGA patients. Results In simple D-TGA, 1) familial recurrence risk is low; 2) children diagnosed prenatally have improved cognitive skills compared with those diagnosed postnatally; 3) echocardiography helps to identify risk factors; 4) routine use of BAS and PGE may not be beneficial in some cases; 5) early ASO improves outcomes and reduces costs with a low mortality. Single or intramural coronary arteries remain risk factors; 6) post-ASO arrhythmias and cardiac dysfunction should raise suspicion of coronary insufficiency; 7) coronary insufficiency and arrhythmias are rare but associated with sudden death; 8) early and late-onset ND abnormalities are common; 9) AR and aortic root dilation are well tolerated; and 10) the aging ASO patient may benefit from “exercise-prescription” rather than restriction. Conclusions Significant strides have been made in understanding risk factors for cardiac, ND and other important clinical outcomes after ASO. PMID:25082585

  14. Identification and Quantification of Mineral Precipitation in Fe 0 Filings From a Column Study

    SciTech Connect

    Kamolpornwijit, Wiwat; Liang, Liyuan; Moline, Gerilyn; Hart, Todd R.; West, Olivia

    2004-09-29

    Quantifying precipitates and determining corrosion rates of zero-valent iron (Fe 0 ) during groundwater treatment were pursued in two field columns by analyzing column core samples using thermo-gravimetric analysis (TGA) combined with x-ray diffraction (XRD) and scanning electron microscopy (SEM). The core precipitates included goethite, magnetite, aragonite, and calcite as major phases with lesser amounts of Fe?(OH)?CO?, and green rust, similar to other studies [1-5]. Corrosion rates derived from TGA-MS analysis of core samples ranged in 0.5 ? 6.1 mmol kg -1 d -1 , higher than a previous report [6] but not unreasonable considering that the influent contained up to 13.5 mM NO? - . At the inlet sand-Fe 0 interface, corrosion rates were similar (4.09 and 4.86 mmol kg -1 d -1 ) for both columns. Corrosion rates derived from pore water chemistry showed a decreasing trend over time. The time-weighted average corrosion rates for both columns of different throughput fell in the range based on TGA-MS results, suggesting that the aqueous mass balance calculation could provide an alternative to estimating corrosion rates in the absence of core analyses. The porosity reduction based on water chemistry was confirmed by TGA-MS results (7?77%), where the high porosity reduction occurred at reactive regions and the low at regions near the effluent. Normalized with the treatment volume, porosity reduction values agree with other studies that used high levels of SO? ?- and HCO? - [2,7,8]. The near 80% porosity reduction in more corroded regions, subjected to high throughput of an equivalent of 17-yr operation, is significant to be considered for long-term performance of permeable reactive barriers.

  15. Polar-Nonpolar Radical Copolymerization under Li+ Catalysis

    DTIC Science & Technology

    2008-09-21

    description of our copolymerization results. The polyisobutylene (b- PIB ) that is produced by homopolymerization of IB in an inert solvent such as 1,2...the linear polyisobutylene (l- PIB ) produced under the usual cationic initiation. The difference is clear in spectral (NMR) and physical (DSC, TGA...HPLC) properties. A detailed 2D-NMR examination of b- PIB obtained from ordinary IB and several isotopically labeled versions of IB revealed that its

  16. (YIP-10) Enabling Dynamic Oxidation Mechanisms in Reverse Infiltrated Ultra-High Temperature Ceramic Coated C-C Composites for Application in Hypersonics

    DTIC Science & Technology

    2013-08-09

    currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES...American Ceramic Society and the International Journal of Applied Ceramic Technology , at the time this report was due. Therefore, an executive summary... pyrolysis and before high temperature oxidation. Figure 2b shows the cross section of C-C composite after oxidation using, DNE-TGA at 1600 °C for 15

  17. CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS FUELS

    SciTech Connect

    Dr. Kalyan Annamalai; Dr. John Sweeten; Dr. Sayeed Mukhtar

    2001-05-10

    The following are proposed activities for quarter 3 (12/15/00-3/14/01): (1) Conduct TGA and fuel characterization studies - Task 1; (2) Continue to perform re-burn experiments. - Task 2; (3) Design fixed bed combustor. - Task 3; and (4) Modify the PCGC2 code to include moisture evaporation model - Task 4. The following were achieved During Quarter 3 (12/15/0-3/14/01): (1) Conducted TGA and Fuel Characterization studies (Appendix I). A comparison of -fuel properties, TGA traces etc is given in Appendix I. Litter has 3 and 6 times more N compared to coal on mass and heat basis. The P of litter is almost 2 % (Task 1). Both litter biomass (LB) and feedlot biomass (FB) have been pulverized. The size distributions are similar for both litter and FB in that 75 % pass through 150 {micro}m sieve while for coal 75 % pass through 60 {micro}m sieve. Rosin Rammler curve parameters are given. The TGA characteristics of FB and LB are similar and pyrolysis starts at 100 C below that of coal; (2) Reburn experiments with litter and with FB have been performed (Appendix II) -Task 2. Litter is almost twice effective (almost 70--90 % reduction) compared to coal in reducing the NOx possibly due to presence of N in the form of NH{sub 3}; (3) Designed fixed bed gasifier/combustor (Appendix III) - Task 3; and (4) Modified PCGC2 to include moisture evaporation model in coal and biomass particles. (Appendix IV) - Task 4.

  18. Robust Fiber Coatings

    DTIC Science & Technology

    2002-08-01

    33 25 TGA curve of powder contained from dried Al-metal/formic Acid/ oxalic acid alumina precursor...ligands that may decompose to more benign species at the higher temperatures. We have tried to replace the nitrates with oxalic acid , ethylene glycol...or formic acid. Oxalic acid , ethylene glycol or formic acid was simply added to the alumina polymer solution and refluxed. Figure 20 shows the

  19. A comparative kinetics study of thermal degradation of some novel ABA block copolymers

    NASA Astrophysics Data System (ADS)

    Blanco, Ignazio; Cicala, Gianluca; Mamo, Antonino; Latteri, Alberta; Recca, Antonino

    2012-07-01

    Some novel ABA block copolymers, synthesized with three different molecular weights, where the block A is a PPO while the block B is a random copoly(aryl ether sulfone), were studied by TGA and DTA techniques, in both flowing nitrogen and static air atmosphere, in order to draw useful information about their resistance to thermal degradation. The results obtained for the various compounds investigated were discussed and compared with each other and a thermal stability classifications in the studied environments were made.

  20. NOVEL CERAMIC MEMBRANE FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION

    SciTech Connect

    Jun-ichi Ida; Zhaohui Yang; Jerry Y.S. Lin

    2002-03-01

    A double layer model to describe the mechanism of CO{sub 2} sorption/desorption for both pure and modified lithium zirconate was proposed based on the all data obtained so far with the help of TGA, DSC and XRD analysis. The model can elucidate well the CO{sub 2} sorption/desorption behavior of lithium zircocnate in both pure and modified cases.

  1. Development of and fabrication of high resolution gas chromatographic capillary columns

    NASA Technical Reports Server (NTRS)

    Zlatkis, A.

    1982-01-01

    Gas chromatographic columns which are used in the trace gas analyzer (TGA) for the space shuttle are coated with a polyoxyethylene lauryl ether. This stationary phase is of medium polarity and has a temperature limit of 160 C. A polymer for this application which has an improved thermal stability is investigated. The use of fused silica capillary columns with specially bonded phases as well as an introduction system (on column) was also studied.

  2. Optical properties of colloidal CdS and ZnS quantum dots nanoparticles

    NASA Astrophysics Data System (ADS)

    Amran, Afiqah Shafify; Shamsudin, Siti Aisyah

    2016-11-01

    CdS and ZnS nanoparticles are luminescent semiconductors with great properties to be used in biosensors. Both semiconducting nanoparticles were synthesized in distilled water by using the simple colloidal method. Thioglycolic acid (TGA) was used as a stabilizer and Polyethyleneimine (PEI) was used as a surface modifier. The chemical composition and optical properties of the CdS and ZnS nanoparticles were investigated using Ultra Violet (UV) lamp, UV Spectroscopy and Photoluminescence (PL) Spectroscopy.

  3. Lisicon Glass-Ceramics Mediated Catalysis of Oxygen Reduction

    DTIC Science & Technology

    2011-06-01

    oxygen. In this context, the Lisicon structure resembles the structure of well-known zeolites . It is conceivable that in addi- tion to an ability to...process followed by a nucleation and crystallization thermal treatments. Fu (Refs. 3 and 4) reported processing and characterization of lithium ion...CV measurements. Thermal characterization was conducted on approximately 10 mg of LAGP specimen using TGA (TA Instruments, model 2050). The specimens

  4. In Situ Raman Spectroscopy of the Nanodiamond-to-Carbon Onion Transformation During Thermal Annealing of Detonation Nanodiamond Powder

    DTIC Science & Technology

    2012-06-01

    nanotubes. Recent improvements in synthesis techniques and a rapidly increasing number of potential applications have sparked growing interest in these...information on transformation kinetics and potential activation barriers. • Utilize complementary characterization techniques (XRD, HRTEM, TGA) to support...stage to perform a useful Raman measurement. Sample loss was either due to the sample being entrained and carried away by the Ar gas purge or due to

  5. Synthesis of cadmium selenide colloidal quantum dots in aquatic medium

    NASA Astrophysics Data System (ADS)

    Mazing, D. S.; Matyushkin, L. B.; Aleksandrova, O. A.; Mikhailov, I. I.; Moshnikov, V. A.; Tarasov, S. A.

    2014-12-01

    Cadmium selenide nanocrystals were prepared in water phase through facile wet chemistry technique with thioglycolic acid (TGA) acting as capping agent. Structures were characterized using X-ray diffraction (XRD), UV-vis absorption and photoluminescence spectroscopies. Depending on synthesis conditions nanoparticles exhibit photoluminescence with maximum in the region of 580 - 680 nm. Influence of technological parameters and component concentrations on nanocrystals average size and properties was studied.

  6. Development of Conducting Polymers of High Structural Strength

    DTIC Science & Technology

    1988-05-31

    electrical conductivity measurements over an extended range of temperatures for both pristine and chemically doped samples. Doping of samples by ion...GPC, TGA, DSC , TMA, etc. were charried out. Defects which limit optical nonlinearity have been identified. The most serious of these appears to be...been synthesized. For example, we have prepared copolymers of polythiophene and polyaniline and have characterized the nonlinear optical as well as

  7. Synthesis and properties of dicationic ionic liquids containing a siloxane structural moiety

    NASA Astrophysics Data System (ADS)

    Glukhov, L. M.; Krasovskiy, V. G.; Chernikova, E. A.; Kapustin, G. I.; Kustov, L. M.; Koroteev, A. A.

    2015-12-01

    Five new ionic liquids formed by doubly charged cations containing a siloxane moiety and bis(trifluoromethylsulfonyl) imide anion are synthesized and characterized. Their thermal stability is studied by means of TGA; melting points (glass transition temperatures) and densities are measured. The temperature dependences of kinematic viscosity of the obtained ionic liquids are presented along with their approximations by the Vogel-Tammann-Fulcher equation.

  8. Effect of Silicon Substitution on the Crystal Properties of Cyanate Ester Monomers (Briefing Charts)

    DTIC Science & Technology

    2015-08-17

    Approved for public release; distribution is unlimited.   The Use of Si in Thermosetting Polymers • In addition to the expected increase in short...rigid form, are known (e.g. Wright et al., Polymer Preprints, 2004, 45(2), 294. TGA in Air (heating rate 10 °C / min.) Weight Gain in Boiling Water

  9. Surgical management of a neonate with congenitally corrected transposition of the great vessels, hypoplastic right aortic arch, and Ebstein anomaly.

    PubMed

    Filippelli, Sergio; Perri, Gianluigi; Kirk, Richard; Hasan, Asif; Griselli, Massimo

    2013-11-01

    We report a neonate with a primary diagnosis of congenitally corrected transposition (ccTGA) of the great vessels, hypoplastic right aortic arch, and a severely regurgitant Ebstein tricuspid valve (TV). During the fetal period, she was listed for heart transplantation, and two weeks after birth due to a deterioration of her general condition, we performed a Norwood-Sano modified procedure. After 58 days a donor heart became available and the baby successfully received a orthotopic heart transplantation.

  10. Medicine shortages in Australia: causes, impact and management strategies in the community setting.

    PubMed

    Tan, Yee Xi; Moles, Rebekah J; Chaar, Betty B

    2016-10-01

    Background Medicine shortages are an ongoing global problem. The Therapeutic Goods Administration (TGA) dedicated a website for monitoring of medicine shortages in Australia in May 2014, as part of the Medicine Shortage Information Initiative. This study aimed to explore the views of pharmacists regarding medicine shortages in the community setting and the impact of the TGA website in Australia. Setting Community pharmacies in New South Wales, Australia. Method Twenty semi-structured interviews were conducted with community pharmacists. Data collected were analysed thematically utilising the framework analysis method. Main outcome measure Qualitative analysis conducted using the framework approach. Results Findings clearly indicated that medicine shortages were experienced on a regular basis, but most participants were unaware of the TGA website. Medicine shortages reportedly impacted both pharmacists and consumers; and various workarounds were undertaken to manage the issue. The "price disclosure policy" was found to be a prominent contributing factor in emerging shortages. Suggestions were made for ways to improve the growing occurrence of shortages. Conclusion Overall, the study found that there was a lack of familiarity with the TGA website, despite experiencing regular shortages of medicines in practice. Also highlighted, was the importance of pharmacists prioritising patient care over business decisions. To reduce prescribing of out-of-stock medicines notifying doctors about shortages was also considered important, to allow for early action to be taken at higher levels of the supply chain. Findings of this study may help direct future policy-making around the world, as medicine shortages is a problem shared by healthcare providers in most countries around the world.

  11. New Reactive Diluents for an Environmentally Efficient Approach to Composite Repair

    DTIC Science & Technology

    2010-02-16

    simultaneous differential thermal analyzer STEL short term exposure limit TGA thermogravimetric analysis TMA thermomechanical analysis Tg...their metal counter parts so there is significant savings in maintenance over a component lifetime and DoD can avoid the use of toxic corrosion...purification. Since the physical state of these materials could not be predicted beforehand, the successful synthesis of liquid molecules eliminated one of

  12. Formation of silver iodide nanoparticles on silk fiber by means of ultrasonic irradiation.

    PubMed

    Abbasi, Amir Reza; Morsali, Ali

    2010-04-01

    The growth of silver iodide nanoparticles on silk fiber was achieved by sequential dipping in an alternating bath of potassium iodide and silver nitrate under ultrasound irradiation. Some parameters such as effect of pH, concentration and numerous sequential dipping in growth of the nanocrystal have been studied. The samples were characterized with powder X-ray diffraction (XRD), scanning electron microscopy (SEM), ICP, TGA and solid state UV-vis spectroscopy.

  13. Growth and Studies of Halides doped Zinc Tris-Thiourea Sulphate(HZTS) Crystals

    NASA Astrophysics Data System (ADS)

    Suveetha, P.; Sathya, T.; Sudha, S.; Raj, M. B. Jessie

    2012-10-01

    Single crystals of Sodium chloride and Potassium iodide (Halides) doped Zinc tris-thiourea sulphate (ZTS) were grown from low temperature solution growth technique by slow evaporation method using water as solvent. The powder X-Ray diffraction pattern were recorded and indexed. The UV transmittance spectrum has been recorded. The optical band gap was estimated using Taucís plot. The TGA/DTA studies show the thermal properties of the crystals.

  14. Transient Thermal Stability of Polymer Nanocomposites

    DTIC Science & Technology

    2012-08-01

    Temperatures exceed melting point and degradation temp of base polymer • Nanoclay and Nanotubes provide degradation resistance • Novel TGA-LPH...difference in heating rate 0 500 1000 1500 2000 0 4 8 12 time (ms) S u rf a c e t e m p e ra tu re ( K ) 120mm cannon Use polypropylene as a model...system to investigate degradation kinetics during transient heating Goal of this project Materials Isotactic Polypropylene + 0-50 wt % nanoclay

  15. Temperature dependent phase transformation in nano sized magnesium ferrite

    NASA Astrophysics Data System (ADS)

    Sumangala T., P.; Mahender, C.; Venkataramani, N.; Prasad, Shiva

    2015-06-01

    The phase transformation in nanosized stoichiometric magnesium ferrite is being discussed. It was shown by TGA/DSC that there exist two reactions (shown by exothermic peaks) in nano sized magnesium ferrite when synthesized by sol gel combustion synthesis. First one of these reactions resulted in the precipitation of α-Fe2O3 and a resultant spinel. The second reaction resulted in stoichiometric spinel from this two phase system.

  16. Thermal stability enhancement of rubbery ormosils

    SciTech Connect

    Kramer, S.J.; Mackenzie, J.D.

    1994-12-31

    Thermal stability of a novel rubbery ORMOSIL of condensed tetraethoxysilane (TEOS) and polydimethylsiloxane (PDMS) was investigated along with methods by which to improve this stability. Based upon literature review of siloxane systems, modifications of the base ORMOSIL system was made which included substitution of polydimethyldiphenylsiloxane (PDMDPS) for PDMS, adding antioxidant, and adding iron compounds. Relative enhancement was investigated in terms of resilience measurements, and was also analyzed with thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA).

  17. Variation in performance of surfactant loading and resulting nitrate removal among four selected natural zeolites.

    PubMed

    Guan, Huade; Bestland, Erick; Zhu, Chuanyu; Zhu, Honglin; Albertsdottir, Dora; Hutson, John; Simmons, Craig T; Ginic-Markovic, Milena; Tao, Xian; Ellis, Amanda V

    2010-11-15

    Surfactant modified zeolites (SMZs) have the capacity to target various types of water contaminants at relatively low cost and thus are being increasingly considered for use in improving water quality. It is important to know the surfactant loading performance of a zeolite before it is put into application. In this work we compare the loading capacity of a surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br), onto four natural zeolites obtained from specific locations in the USA, Croatia, China, and Australia. The surfactant loading is examined using thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectroscopy. We then compare the resulting SMZs performance in removing nitrate from water. Results show that TGA is useful to determine the HDTMA loading capacity on natural zeolites. It is also useful to distinguish between a HDTMA bi-layer and a HDTMA mono-layer on the SMZ surface, which has not been previously reported in the literature. TGA results infer that HDTMA (bi-layer) loading decreases in the order of US zeolite>Croatian zeolite>Chinese zeolite>Australian zeolite. This order of loading explains variation in performance of nitrate removal between the four SMZs. The SMZs remove 8-18 times more nitrate than the raw zeolites. SMZs prepared from the selected US and Croatian zeolites were more efficient in nitrate removal than the two zeolites commercially obtained from Australia and China.

  18. Spatial variability of tidal gravity anomalies and its correlation with the effective elastic thickness of the lithosphere

    NASA Astrophysics Data System (ADS)

    Shukowsky, Wladimir; Mantovani, Marta S. M.

    1999-07-01

    Associations of the Earth tidal gravity response to physical properties of the lithosphere have been attempted at least for the last four decades. Although experimental data suggest this association, rigorous models have not yet been proposed. In this work, statistical tests are performed on the available World Gravity Earth Tides data set. Autocorrelation analysis shows that the M2 tidal gravity anomalies (TGAs) are significantly correlated up to a distance of about 500 km, with an approximately exponential correlation decay. The analysis of the latitudinal dependence of the anomalies shows that the anomaly variance, estimated inside of different latitude bands, follows a cos 4ϕ curve within the ±45° latitude interval and defines the noise level for the M2 gravity anomaly data set. The regression analysis between M2 TGA and the lithosphere effective elastic thickness (EET) estimates shows that these quantities are significantly correlated, with a correlation coefficient of -0.82. The wide range of TGA and EET values, combined with a good global distribution of the data used in the regression analysis, makes the regression equation suitable to be used as a predictor for EET values in areas where M2 TGA data exist and meet the required quality criteria.

  19. Isothermal thermogravimetric data acquisition analysis system

    NASA Technical Reports Server (NTRS)

    Cooper, Kenneth, Jr.

    1991-01-01

    The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

  20. Stability and loading properties of curcumin encapsulated in Chlorella vulgaris.

    PubMed

    Jafari, Yaser; Sabahi, Hossein; Rahaie, Mahdi

    2016-11-15

    Curcumin (Cur), a polyphenols with pharmacological function, was successfully encapsulated in algae (Alg) cell (Chlorella vulgaris) as confirmed by fluorescence microscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform-infrared spectroscopy (FT-IR). Fluorescence micrographs, TGA, DSC and FTIR spectra suggested the hypothesis inclusion Cur in Nano-empty spaces inside cell wall of Alg. The TGA analysis showed that the thermal stability of Alg and Cur at algae/curcumin complex was 3.8% and 33% higher than their free forms at 0-300°C and 300-600°C ranges, respectively. After encapsulation in Alg cells, the photostability of Cur was enhanced by about 2.5-fold. Adsorption isotherm of Cur into Alg was fitted with the Freundlich isotherm. The microcapsules were loaded with Cur up to about 55% w/w which is much higher than other reported bio-carriers. In conclusion, the data proved that Chlorella vulgaris cell can be used as a new stable carrier for Cur.

  1. Synthesis of nano-structured La0.8Ba0.2MnO3 perovskite via a mechano-thermal route

    NASA Astrophysics Data System (ADS)

    Sadighi, Zoya; Ataie, Abolghasem; Barati, Mohammad Reza

    2014-01-01

    In this study, barium-doped lanthanum manganite, La0.8Ba0.2MnO3, was synthesized via a mechano-thermal route employing high energy ball milling and subsequent heat treatment. The structural evolution, morphology and thermal behaviour of the powders were evaluated using XRD, FESEM, and DTA/TGA, respectively. DTA/TGA results showed that the calcination temperature of the carbonates significantly decreased by increasing the milling time. The results revealed that single phase perovskite was formed at 900 °C in a milled sample for 2 h and this temperature decreased to 600 °C by increasing the milling time to 30 h. The mean crystallite size also decreased from 32 to 20 nm by increasing the milling time from 2 to 30 h. The reaction sequence of La0.8Ba0.2MnO3 formation via the mechano-thermal route is proposed using XRD and DTA/TGA results. FESEM micrographs showed that the mean particle size of the perovskite phase is increased slightly from 30 to 40 nm by increasing the heat treatment temperature from 600 to 900 °C.

  2. Kinetic study of solid waste pyrolysis using distributed activation energy model.

    PubMed

    Bhavanam, Anjireddy; Sastry, R C

    2015-02-01

    The pyrolysis characteristics of municipal solid waste, agricultural residues such as ground nut shell, cotton husk and their blends are investigated using non-isothermal thermogravimetric analysis (TGA) with in a temperature range of 30-900 °C at different heating rates of 10 °C, 30 °C and 50 °C/min in inert atmosphere. From the thermograms obtained from TGA, it is observed that the maximum rate of degradation occurred in the second stage of the pyrolysis process for all the solid wastes. The distributed activation energy model (DAEM) is used to study the pyrolysis kinetics of the solid wastes. The kinetic parameters E (activation energy), k0 (frequency factor) are calculated from this model. It is found that the range of activation energies for agricultural residues are lower than the municipal solid waste. The activation energies for the municipal solid waste pyrolysis process drastically decreased with addition of agricultural residues. The proposed DAEM is successfully validated with TGA experimental data.

  3. Surface esterification of cellulose nanofibers by a simple organocatalytic methodology.

    PubMed

    Avila Ramírez, Jhon Alejandro; Suriano, Camila Juan; Cerrutti, Patricia; Foresti, María Laura

    2014-12-19

    Bacterial cellulose nanofibers were esterified with two short carboxylic acids by means of a simple and novel organic acid-catalyzed route. The methodology proposed relayed on the use of a non-toxic biobased α-hydroxycarboxylic acid as catalyst, and proceeded under moderate reaction conditions in solventless medium. By varying the esterification interval, acetylated and propionized bacterial cellulose nanofibers with degree of substitution (DS) in the 0.02-0.45 range could be obtained. Esterified bacterial cellulose samples were characterized by means of Solid-State CP/MAS (13)C Nuclear Magnetic Resonance spectroscopy (CP/MAS (13)C NMR), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and chosen hydrophobicity test assays. TGA results showed that the esterified nanofibers had increased thermal stability, whereas XRD data evidenced that the organocatalytic esterification protocol did not alter their crystallinity. The analysis of the ensuing modified nanofibers by NMR, FTIR, XRD and TGA demonstrated that esterification occurred essentially at the surface of bacterial cellulose microfibrils, something highly desirable for changing their surface hydrophilicity while not affecting their ultrastructure.

  4. Psychosocial outcomes for preschool children and families after surgery for complex congenital heart disease.

    PubMed

    Brosig, C L; Mussatto, K A; Kuhn, E M; Tweddell, J S

    2007-01-01

    The purpose of the current study was to assess the psychosocial outcomes of preschool-aged survivors (ages 3-6 years) of hypoplastic left heart syndrome (HLHS; n=13) and transposition of the great arteries (TGA; n=13). Parents completed the following measures: Pediatric Quality of Life Inventory, Impact on the Family Scale, Parenting Stress Index, Parent Behavior Checklist, and Child Behavior Checklist. Quality of life scores did not differ from those of healthy controls. Parents of children with HLHS reported more negative impact of the child's illness on the family and more parenting stress than parents of children with TGA. Parents of both groups of children were more permissive in their parenting style than parents of healthy controls. Children with HLHS had higher rates of attention and externalizing behavior problems than children with TGA. The results highlight the need for practitioners working with these children and families to ask about parental stress, family functioning, and behavioral expectations for the child in the context of routine medical/cardiac follow-up.

  5. Syndromes of transient amnesia: towards a classification. A study of 153 cases.

    PubMed Central

    Hodges, J R; Warlow, C P

    1990-01-01

    Of 153 patients presenting with acute transient amnesia, 114 fulfilled the proposed strict diagnostic criteria for transient global amnesia (TGA). The prognosis of this group was excellent with the exception of a small subgroup (7%), largely identifiable because of atypically brief or recurrent attacks, who developed epilepsy of temporal lobe type on follow up. Computerised tomography (CT) scans performed on 95 patients were normal, evidence for covert alcoholism was lacking and there was a familial incidence of approximately 2%. By contrast, the group of 39 patients who did not meet the criteria for TGA had a significantly worse prognosis with a high incidence of major vascular events. The groups could not be distinguished on the basis of behavioural characteristics during the attack. The following classification was proposed: 1) pure TGA--attacks fulfilling the strict criteria, and of more than one hour in duration which do not require detailed investigation, 2) probable epileptic amnesia--attacks of less than an hour or rapidly recurrent, 3) probable transient ischaemic amnesia, a minority of cases with additional focal neurological deficits during the attack. PMID:2266362

  6. A Combined Raman Spectroscopic and Thermogravimetric Analysis Study on Oxidation of Coal with Different Ranks

    PubMed Central

    Zhang, Weiqing; Jiang, Shuguang; Hardacre, Christopher; Goodrich, Peter; Wang, Kai; Shao, Hao; Wu, Zhengyan

    2015-01-01

    Raman spectroscopy and nonisothermal thermogravimetric analysis (TGA) measurements have been reported for different rank coals (lignite, bituminous coal, and anthracite) and the relationship between the measurements was examined. It was found that the Raman spectra parameters can be used to characterize structure changes in the different rank coals, such as the band area ratios based on the curve-fitted results. Higher ranked coal was found to have higher values of IGR/IAll and I(G + GR)/IAll but lower values of ID/I(G+GR), IDL/I(G+GR), I(S + SL)/I(G+GR), and I(GL+GL')/I(G+GR). The oxidation properties of the coal samples were characterized by the reactivity indexes Tig, T20%, and Tmax from TGA data which were found to correlate well with the band area ratios of IGR/IAll, I(G + GR)/IAll, and I(S + SL)/I(G+GR). Based on these correlations, the Raman band area ratios were found to correlate with the oxidation activity of coal providing additional structural information which can be used to understand the changes in the TGA measurements. PMID:26682084

  7. Necrotrophic pathogens use the salicylic acid signaling pathway to promote disease development in tomato.

    PubMed

    Rahman, Taha Abd El; Oirdi, Mohamed El; Gonzalez-Lamothe, Rocio; Bouarab, Kamal

    2012-12-01

    Plants use different immune pathways to combat pathogens. The activation of the jasmonic acid (JA)-signaling pathway is required for resistance against necrotrophic pathogens; however, to combat biotrophic pathogens, the plants activate mainly the salicylic acid (SA)-signaling pathway. SA can antagonize JA signaling and vice versa. NPR1 (noninducible pathogenesis-related 1) is considered a master regulator of SA signaling. NPR1 interacts with TGA transcription factors, ultimately leading to the activation of SA-dependent responses. SA has been shown to promote disease development caused by the necrotrophic pathogen Botrytis cinerea through NPR1, by suppressing the expression of two JA-dependent defense genes, proteinase inhibitors I and II. We show here that the transcription factor TGA1.a contributes to disease development caused by B. cinerea in tomato by suppressing the expression of proteinase inhibitors I and II. Finally, we present evidence that the SA-signaling pathway contributes to disease development caused by another necrotrophic pathogen, Alternaria solani, in tomato. Disease development promoted by SA through NPR1 requires the TGA1.a transcription factor. These data highlight how necrotrophs manipulate the SAsignaling pathway to promote their disease in tomato.

  8. A Genetic Screen Identifies a Requirement for Cysteine-Rich–Receptor-Like Kinases in Rice NH1 (OsNPR1)-Mediated Immunity

    PubMed Central

    Chern, Mawsheng; Xu, Qiufang; Bart, Rebecca S.; Bai, Wei; Ruan, Deling; Sze-To, Wing Hoi; Canlas, Patrick E.; Jain, Rashmi; Chen, Xuewei; Ronald, Pamela C.

    2016-01-01

    Systemic acquired resistance, mediated by the Arabidopsis NPR1 gene and the rice NH1 gene, confers broad-spectrum immunity to diverse pathogens. NPR1 and NH1 interact with TGA transcription factors to activate downstream defense genes. Despite the importance of this defense response, the signaling components downstream of NPR1/NH1 and TGA proteins are poorly defined. Here we report the identification of a rice mutant, snim1, which suppresses NH1-mediated immunity and demonstrate that two genes encoding previously uncharacterized cysteine-rich-receptor-like kinases (CRK6 and CRK10), complement the snim1 mutant phenotype. Silencing of CRK6 and CRK10 genes individually in the parental genetic background recreates the snim1 phenotype. We identified a rice mutant in the Kitaake genetic background with a frameshift mutation in crk10; this mutant also displays a compromised immune response highlighting the important role of crk10. We also show that elevated levels of NH1 expression lead to enhanced CRK10 expression and that the rice TGA2.1 protein binds to the CRK10 promoter. These experiments demonstrate a requirement for CRKs in NH1-mediated immunity and establish a molecular link between NH1 and induction of CRK10 expression. PMID:27176732

  9. A selective determination of copper ions in water samples based on the fluorescence quenching of thiol-capped CdTe quantum dots.

    PubMed

    Nurerk, Piyaluk; Kanatharana, Proespichaya; Bunkoed, Opas

    2016-03-01

    CdTe quantum dots (QDs) capped with different stabilizers, i.e. thioglycolic acid (TGA), 3-mercaptopropionic acid (MPA) and glutathione (GSH) were investigated as fluorescent probes for the determination of Cu(2+). The stabilizer was shown to play an important role in both the sensitivity and selectivity for the determination of Cu(2+). TGA-capped CdTe QDs showed the highest sensitivity, followed by the MPA and GSH-capped CdTe QDs, respectively. The TGA- and MPA-capped CdTe QDs were not selective for Cu(2+) that was affected by Ag(+). The GSH-capped CdTe QDs were insensitive to Ag(+) and were used to determine Cu(2+) in water samples. Under optimal conditions, quenching of the fluorescence intensity (F0/F) increased linearly with the concentration of Cu(2+) over a range of 0.10-4.0 µg/mL and the detection limit was 0.06 µg/mL. The developed method was successfully applied to the determination of Cu(2+) in water samples. Good recoveries of 93-104%, with a relative standard deviation of < 6% demonstrated that the developed simple method was accurate and reliable. The quenching mechanisms were also described.

  10. THERMAL ANALYSIS OF WASTE GLASS MELTER FEEDS

    SciTech Connect

    KRUGER AA; HRMA PR; POKORNY R; PIERCE DA

    2011-10-21

    Melter feeds for high-level nuclear waste (HLW) typically contain a large number of constituents that evolve gas on heating, Multiple gas-evolving reactions are both successive and simultaneous, and include the release of chemically bonded water, reactions of nitrates with organics, and reactions of molten salts with solid silica. Consequently, when a sample of a HLW feed is subjected to thermogravimetric analysis (TGA), the rate of change of the sample mass reveals multiple overlapping peaks. In this study, a melter feed, formulated for a simulated high-alumina HLW to be vitrified in the Waste Treatment and Immobilization Plant, currently under construction at the Hanford Site in Washington State, USA, was subjected to TGA. In addition, a modified melter feed was prepared as an all-nitrate version of the baseline feed to test the effect of sucrose addition on the gas-evolving reactions. Activation energies for major reactions were determined using the Kissinger method. The ultimate aim of TGA studies is to obtain a kinetic model of the gas-evolving reactions for use in mathematical modeling of the cold cap as an element of the overall model of the waste-glass melter. In this study, we focused on computing the kinetic parameters of individual reactions without identifying their actual chemistry, The rough provisional model presented is based on the first-order kinetics.

  11. MEASUREMENT OF TRITIUM DURING VOLOXIDATION OF ZIRCALOY-2 FUEL HULLS

    SciTech Connect

    Crowder, M.; Laurinat, J.; Stillman, J.

    2010-10-14

    A straightforward method to evaluate the tritium content of Zircaloy-2 cladding hulls via oxidation of the hull and capture of the volatilized tritium in liquids has been demonstrated. Hull samples were heated in air inside a thermogravimetric analyzer (TGA). The TGA was rapidly heated to 1000 C to oxidize the hulls and release absorbed tritium. To capture tritium, the TGA off-gas was bubbled through a series of liquid traps. The concentrations of tritium in bubbler solutions indicated that tritiated water vapor was captured nearly quantitatively. The average tritium content measured in the hulls was 19% of the amount of tritium produced by the fuel, according to ORIGEN2 isotope generation and depletion calculations. Published experimental data show that Zircaloy-2 oxidation follows an Arrhenius model, and that an initial, nonlinear oxidation rate is followed by a faster, linear rate after 'breakaway' of the oxide film. This study demonstrates that the linear oxidation rate of Zircaloy samples at 974 C is faster than predicted by the extrapolation of data from lower temperatures.

  12. A Novel DNA Binding Mechanism for maf Basic Region-Leucine Zipper Factors Inferred from a MafA-DNA Complex Structure and Binding Specificities

    SciTech Connect

    Lu, Xun; Guanga, Gerald P; Wan, Cheng; Rose, Robert B

    2012-11-13

    MafA is a proto-oncoprotein and is critical for insulin gene expression in pancreatic β-cells. Maf proteins belong to the AP1 superfamily of basic region-leucine zipper (bZIP) transcription factors. Residues in the basic helix and an ancillary N-terminal domain, the Extended Homology Region (EHR), endow maf proteins with unique DNA binding properties: binding a 13 bp consensus site consisting of a core AP1 site (TGACTCA) flanked by TGC sequences and binding DNA stably as monomers. To further characterize maf DNA binding, we determined the structure of a MafA–DNA complex. MafA forms base-specific hydrogen bonds with the flanking G–5C–4 and central C0/G0 bases, but not with the core-TGA bases. However, in vitro binding studies utilizing a pulse–chase electrophoretic mobility shift assay protocol revealed that mutating either the core-TGA or flanking-TGC bases dramatically increases the binding off rate. Comparing the known maf structures, we propose that DNA binding specificity results from positioning the basic helix through unique phosphate contacts. The EHR does not contact DNA directly but stabilizes DNA binding by contacting the basic helix. Collectively, these results suggest a novel multistep DNA binding process involving a conformational change from contacting the core-TGA to contacting the flanking-TGC bases.

  13. Modeling of alkyl quaternary ammonium cations intercalated into montmorillonite lattice

    SciTech Connect

    Daoudi, El Mehdi; Boughaleb, Yahia; El Gaini, Layla; Meghea, Irina; Bakasse, Mina

    2013-05-15

    Highlights: ► The modification of montmorillonites by three surfactants increases the basal spacing. ► The model proposed show a bilayer conformation for the surfactant ODTMA. ► The DODMA and TOMA surfactants adopt a paraffin type arrangement. ► Behavior of surfactants in interlayer space was confirmed by TGA and ATR analysis. - Abstract: The objective of this work was to study the conformation of the quaternary ammonium cations viz., octadecyl trimethyl ammonium (ODTMA), dioctadecyl dimethyl ammonium (DMDOA) and trioctadecyl methyl ammonium (TOMA) intercalated within montmorillonite. The modified montmorillonite was characterized by X-ray diffraction in small angle (SAXS), thermal analysis (TGA) and infrared spectroscopy of attenuated total reflection (ATR). The modification of organophilic montmorillonites by the three surfactants ODTMA, DMDOA and TOMA increases the basal spacing from their respective intercalated distances of 1.9 nm, 2.6 nm and 3.4 nm respectively. The increase in the spacing due to the basic organic modification was confirmed by the results of thermal analysis (TGA) and infrared spectroscopy (ATR), and also supported by theoretical calculations of longitudinal and transversal chain sizes of these alkyl quaternary ammonium cations.

  14. Endogenous prion protein attenuates experimentally induced colitis.

    PubMed

    Martin, Gary R; Keenan, Catherine M; Sharkey, Keith A; Jirik, Frank R

    2011-11-01

    Although the cellular prion protein (PrP(C)) is expressed in the enteric nervous system and lamina propria, its function(s) in the gut is unknown. Because PrP(C) may exert a cytoprotective effect in response to various physiologic stressors, we hypothesized that PrP(C) expression levels might modulate the severity of experimental colitis. We evaluated the course of dextran sodium sulfate (DSS)-induced colitis in hemizygous Tga20 transgenic mice (approximately sevenfold overexpression of PrP(C)), Prnp(-/-) mice, and wild-type mice. On day 7, colon length, disease severity, and histologic activity indices were determined. Unlike DSS-treated wild-type and Prnp(-/-) animals, PrP(C) overexpressing mice were resistant to colitis induction, exhibited much milder histopathologic features, and did not exhibit weight loss or colonic shortening. In keeping with these results, pro-survival molecule expression and/or phosphorylation levels were elevated in DSS-treated Tga20 mice, whereas pro-inflammatory cytokine production and pSTAT3 levels were reduced. In contrast, DSS-treated Prnp(-/-) mice exhibited increased BAD protein expression and a cytokine expression profile predicted to favor inflammation and differentiation. PrP(C) expression from both the endogenous Prnp locus or the Tga20 transgene was increased in the colons of DSS-treated mice. Considered together, these findings demonstrate that PrP(C) has a previously unrecognized cytoprotective and/or anti-inflammatory function within the murine colon.

  15. Understanding medial temporal activation in memory tasks: evidence from fMRI of encoding and recognition in a case of transient global amnesia.

    PubMed

    Westmacott, Robyn; Silver, Frank L; McAndrews, Mary Pat

    2008-01-01

    We used fMRI to examine the activation patterns of patient AE during encoding and recognition of visual scenes during an episode of transient global amnesia (TGA) and 3 months later. Controls (n = 5) showed bilateral (R > L) activation in parahippocampal and fusiform gyri during encoding and right-sided activation in the same regions associated with recognition of previously viewed scenes. AE showed a similar pattern at follow-up. During acute TGA, when performance was profoundly impaired, AE showed no medial temporal activation associated with encoding of new scenes or recognition of old scenes. In both contrasts, the percent signal change in relevant medial temporal regions was more than three standard deviations below the control sample mean. She did, however, show striking bilateral hippocampal activation for recognition attempts (old + new scenes > baseline) even though retrieval was unsuccessful (55% recognition accuracy). This finding was unique to AE on this occasion. This is the first study to document normalization of both encoding and recognition activation patterns in TGA. Furthermore, the strong hippocampal activation during unsuccessful retrieval highlights important issues in interpreting memory-related activations, particularly in dysfunctional systems.

  16. Kinetics of the pyrolysis of arundo, sawdust, corn stover and switch grass biomass by thermogravimetric analysis using a multi-stage model.

    PubMed

    Biney, Paul O; Gyamerah, Michael; Shen, Jiacheng; Menezes, Bruna

    2015-03-01

    A new multi-stage kinetic model has been developed for TGA pyrolysis of arundo, corn stover, sawdust and switch grass that accounts for the initial biomass weight (W0). The biomass were decomposed in a nitrogen atmosphere from 23°C to 900°C in a TGA at a single 20°C/min ramp rate in contrast with the isoconversion technique. The decomposition was divided into multiple stages based on the absolute local minimum values of conversion derivative, (dx/dT), obtained from DTG curves. This resulted in three decomposition stages for arundo, corn stover and sawdust and four stages for switch grass. A linearized multi-stage model was applied to the TGA data for each stage to determine the pre-exponential factor, activation energy, and reaction order. The activation energies ranged from 54.7 to 60.9 kJ/mol, 62.9 to 108.7 kJ/mol, and 18.4 to 257.9 kJ/mol for the first, second and the third decomposition stages respectively.

  17. Coronary artery occlusion after arterial switch operation in an asymptomatic 15-year-old boy

    PubMed Central

    Saini, Ashish P; Cyran, Stephen E; Ettinger, Steven M; Pauliks, Linda B

    2016-01-01

    A 15-year-old boy with transposition of the great arteries (TGA) and neonatal arterial switch operation (ASO) presented with complete occlusion of the left main coronary artery (LMCA). Intra-operatively, an intramural left coronary artery was identified. Therefore, since age 7 years he had a series of screening exercise stress tests. At 13 years old, he had 3 to 4 mm ST segment depression in the infero-lateral leads without symptoms. This progressed to 4.2 mm inferior ST segment depression at 15 years old with normal stress echocardiogram. Sestamibi myocardial perfusion scan and cardiac magnetic resonance imaging was inconclusive. Therefore, a coronary angiogram was obtained which showed complete occlusion of the LMCA with ample collateralization from the right coronary artery system. This was later confirmed on a computed tomogram (CT) angiogram, obtained in preparation of coronary artery bypass grafting. The case illustrates the difficulty of detecting coronary artery stenosis and occlusion in young patients with rich collateralization. Coronary CT angiogram and conventional angiography were the best imaging modalities to detect coronary anomalies in this adolescent with surgically corrected TGA. Screening CT angiography may be warranted for TGA patients, particularly for those with known coronary anomalies. PMID:27574609

  18. [Congenitally corrected transposition of the great vessels in adulthood. The value of noninvasive study methods].

    PubMed

    Weidmann, B; Hänseler, T; Jansen, W; Geppert, R; Mathas, B; Tauchert, M

    1994-08-26

    A 57-year-old man with a cough and increasing exertional dyspnoea for the past 6 weeks was found on examination to have a loud systolic murmur and cardiomegaly with pulmonary congestion. Echocardiography revealed congenitally corrected transposition of the great arteries (cTGA: atrioventricular and ventriculoarterial discordance): a morphologically right ventricle with a tricuspid valve on the left, a morphologically left ventricle with bicuspid a-v valve on the right, the aorta arising ventrally from the left-sided (morphologically right) ventricle. The tricuspid valve showed an Ebstein-like anomaly with obvious regurgitation. Transoesophageal and contrast echocardiography defined valvar anatomy, attachment of the great arteries and cardiac chambers to the venous and arterial circulations, as well as absence of a left to right shunt. Angiography revealed a coronary anatomy typical for cTGA. The exertional dyspnoea responded to diuretics and low doses of ACE inhibitor. Follow-up monitoring of the valvar regurgitation and appropriate endocarditis prophylaxis were recommended. As the haemodynamics in cTGA is normal, in the absence of additional anomalies, it is a congenital cardiac defect which can, though rarely, present first in adulthood. Life expectancy depends on the nature of any additional defects and the degree of commonly associated tricuspid valve regurgitation. As this case demonstrates, echocardiography can largely define the anomalies.

  19. NOVEL CERAMIC MEMBRANE FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION

    SciTech Connect

    Jun-ichi Ida; Zhaohui Yang; Jerry Y.S. Lin

    2001-09-01

    The Objective of this research program is to develop a dense, non porous ceramic membrane for separation of carbon dioxide from flue gas at high temperatures (400-600 C). The research has been focused on addressing several fundamental issues of lithium zirconate (Li{sub 2}ZrO{sub 3}). In the 2nd half research, we conducted various kinds of experiments to understand the CO{sub 2} sorption/desorption mechanism on the pure and modified Li{sub 2}ZrO{sub 3} with the help of TGA, DSC TGA and XRD. DSC TGA results suggest that the melting of Li/K carbonates mixture may play an important role in rapid CO{sub 2} sorption in the case of modified lithium zirconate. The CO{sub 2} desorption experiments show that CO{sub 2} desorption from the modified lithium zirconate follows the same mechanism as that from the pure lithium zirconate. This is different from the CO{sub 2} adsorption on the pure and modified lithium zirconates.

  20. The salicylic acid receptor NPR3 is a negative regulator of the transcriptional defense response during early flower development in Arabidopsis.

    PubMed

    Shi, Zi; Maximova, Siela; Liu, Yi; Verica, Joseph; Guiltinan, Mark J

    2013-05-01

    Arabidopsis non-expressor of PR1 (NPR1) is a transcription co-activator that plays a central role in regulating the transcriptional response to plant pathogens. The NPR family consists of NPR1 and five NPR1-like genes. The NPR1 paralog NPR3 has recently been shown to function as a receptor of the plant hormone salicylic acid and to mediate proteosomal degradation of NPR1. The function of NPR3 protein during early flower development was revealed through a detailed molecular-genetic analysis including promoter transcriptional fusion analysis, phenotype characterization of npr3-3 mutants/overexpressors, and whole-plant fitness analysis. The physical interaction between NPR3 and NPR1/TGA2 was explored using bimolecular fluorescence complementation analysis in onion epidermal cells. Here, we show that NPR3 expression was strongest in the petals and sepals of developing flowers and declined after flower opening. Consistently with this observation, an npr3 knockout mutant displayed enhanced resistance to Pseudomonas syringae infection of immature flowers, but not leaves. Developing npr3 flowers exhibited increased levels of basal and induced PR1 transcript accumulation. However, the npr3 mutant showed lower fitness compared to Col-0 in the absence of pathogen. Moreover, NPR3 was shown to interact with NPR1 and TGA2 in vivo. Our data suggest that NPR3 is a negative regulator of defense responses during early flower development and it may function through the association with both NPR1 and TGA2.

  1. Palliative Senning in the Treatment of Congenital Heart Disease with Severe Pulmonary Hypertension

    PubMed Central

    da Penha, Juliano Gomes; Zorzanelli, Leina; Barbosa-Lopes, Antonio Augusto; Atik, Edimar; Miana, Leonardo Augusto; Tanamati, Carla; Caneo, Luiz Fernando; Miura, Nana; Aiello, Vera Demarchi; Jatene, Marcelo Biscegli

    2015-01-01

    Background Transposition of the great arteries (TGA) is the most common cyanotic cardiopathy, with an incidence ranging between 0.2 and 0.4 per 1000 live births. Many patients not treated in the first few months of life may progress with severe pulmonary vascular disease. Treatment of these patients may include palliative surgery to redirect the flow at the atrial level. Objective Report our institutional experience with the palliative Senning procedure in children diagnosed with TGA and double outlet right ventricle with severe pulmonary vascular disease, and to evaluate the early and late clinical progression of the palliative Senning procedure. Methods Retrospective study based on the evaluation of medical records in the period of 1991 to 2014. Only patients without an indication for definitive surgical treatment of the cardiopathy due to elevated pulmonary pressure were included. Results After one year of follow-up there was a mean increase in arterial oxygen saturation from 62.1% to 92.5% and a mean decrease in hematocrit from 49.4% to 36.3%. Lung histological analysis was feasible in 16 patients. In 8 patients, pulmonary biopsy grades 3 and 4 were evidenced. Conclusion The palliative Senning procedure improved arterial oxygen saturation, reduced polycythemia, and provided a better quality of life for patients with TGA with ventricular septal defect, severe pulmonary hypertension, and poor prognosis. PMID:26559982

  2. Preparation and Thermal Analysis of Ferric Doped PVA-PVP-PPy Composite Films

    NASA Astrophysics Data System (ADS)

    Patil, Ravikumar V.; Ranganath, M. R.; Lobo, Blaise

    2011-12-01

    The preparation and thermal analysis of flexible blend films of pyrrole (Py) polymerized in aqueous solution of poly (vinyl alcohol) (PVA) and poly (vinyl pyrrolidone) (PVP) is described. In-situ polymerization of pyrrole in aqueous solution of PVA and PVP containing ferric chloride (FeCl3) was achieved through vapor sorption, and the films obtained were studied using Differential Scanning Calorimetry (DSC), Thermo-Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). No melting endotherm is seen in the DSC and DTA scans of the composite films, indicating that the sample is amorphous. Degradation of the sample is found to occur at lower temperatures, with increase in doping level (wt% of FeCl3). DSC study was performed between 40 °C and 400 °C. Below 1.2 wt % DL, degradation of the sample occurs in two stages, the first at 310 °C and the second at 440 °C, as seen from DTA and TGA scans. The broad endotherm between 80 °C and 120 °C is due to volatization of moisture (water) absorbed by the sample. Multiple endotherms are observed in DSC and DTA scans of the composite films, for FeCl3 doping levels above 3.8 wt %, and the sample degrades in many different stages at lower temperature, with increase in doping level, as revealed by weight losses in the TGA curve.

  3. Thermal stability, complexing behavior, and ionic transport of polymeric gel membranes based on polymer PVdF-HFP and ionic liquid, [BMIM][BF4].

    PubMed

    Shalu; Chaurasia, S K; Singh, R K; Chandra, S

    2013-01-24

    PVdF-HFP + IL(1-butyl-3-methylimidazolium tetrafluoroborate; [BMIM][BF(4)]) polymeric gel membranes containing different amounts of ionic liquid have been synthesized and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared (FTIR), differential scanning calorimetry, thermogravimetric analysis (TGA), and complex impedance spectroscopic techniques. Incorporation of IL in PVdF-HFP polymer changes different physicochemical properties such as melting temperature (T(m)), thermal stability, structural morphology, amorphicity, and ionic transport. It is shown by FTIR, TGA (also first derivative of TGA, "DTGA") that IL partly complexes with the polymer PVdF-HFP and partly remains dispersed in the matrix. The ionic conductivity of polymeric gel membranes has been found to increase with increasing concentration of IL and attains a maximum value of 1.6 × 10(-2) S·cm(-1) for polymer gel membrane containing 90 wt % IL at room temperature. Interestingly, the values of conductivity of membranes with 80 and 90 wt % of IL were higher than that of pure IL (100 wt %). The polymer chain breathing model has been suggested to explain it. The variation of ionic conductivity with temperature of these gel polymeric membranes follows Arrhenius type thermally activated behavior.

  4. Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses.

    PubMed

    Kumpiene, Jurate; Robinson, Ryan; Brännvall, Evelina; Nordmark, Désirée; Bjurström, Henrik; Andreas, Lale; Lagerkvist, Anders; Ecke, Holger

    2011-01-01

    Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses. The speciation of TOC by chemical degradation also showed a presence of a non-degradable C fraction in all materials (60% of TOC in ash, 30% in residual waste and 13% in soil), though in smaller amounts than those determined by TGA. In principle, chemical degradation method can give an indication of the presence of potentially inert C in various waste materials, while TGA is a more precise technique for C speciation, given that waste-specific method adjustments are made. The standard TOC measurement yields exaggerated estimates of organic carbon and may therefore overestimate the potential environmental impacts (e.g. landfill gas generation) of waste materials in a landfill environment.

  5. Hydrogen measurement during steam oxidation using coupled thermogravimetric analysis and quadrupole mass spectrometry

    SciTech Connect

    Parkison, Adam J.; Nelson, Andrew Thomas

    2016-01-11

    An analytical technique is presented with the goal of measuring reaction kinetics during steam oxidation reactions for three cases in which obtaining kinetics information often requires a prohibitive amount of time and cost. The technique presented relies on coupling thermogravimetric analysis (TGA) with a quantitative hydrogen measurement technique using quadrupole mass spectrometry (QMS). The first case considered is in differentiating between the kinetics of steam oxidation reactions and those for simultaneously reacting gaseous impurities such as nitrogen or oxygen. The second case allows one to independently measure the kinetics of oxide and hydride formation for systems in which both of these reactions are known to take place during steam oxidation. The third case deals with measuring the kinetics of formation for competing volatile and non-volatile oxides during certain steam oxidation reactions. In order to meet the requirements of the coupled technique, a methodology is presented which attempts to provide quantitative measurement of hydrogen generation using QMS in the presence of an interfering fragmentation species, namely water vapor. This is achieved such that all calibrations and corrections are performed during the TGA baseline and steam oxidation programs, making system operation virtually identical to standard TGA. Benchmarking results showed a relative error in hydrogen measurement of 5.7–8.4% following the application of a correction factor. Lastly, suggestions are made for possible improvements to the presented technique so that it may be better applied to the three cases presented.

  6. An efficient synthesis of graphenated carbon nanotubes over the tailored mesoporous molecular sieves by chemical vapor deposition

    SciTech Connect

    Atchudan, R.; Joo, Jin.; Pandurangan, A.

    2013-06-01

    Highlights: ► Tailored 3D cubic Ni/KIT-6 with large pores was synthesized successfully. ► The new hybrid g-CNTs in large scale were synthesized using Ni/KIT-6 by CVD method. ► The use of mesoporous material by CVD method would be an ideal choice to prepare g-CNTs at reasonable cost. ► This type of g-CNTs might be a new avenue for nano-electronic applications. - Abstract: The new hybrid of graphenated carbon nanotubes (g-CNTs) was superior to either CNTs or graphene. Mesoporous 3D cubic Ni/KIT-6 were synthesized hydrothermally through organic template route and then were used as catalytic template for the production of g-CNTs using acetylene as a carbon precursor by chemical vapor deposition (CVD) method. The deposited new hybrid carbon materials were purified and analyzed by various physico-chemical techniques such as XRD, TGA, SEM, TEM and Raman spectroscopy techniques. The graphitization of CNTs was confirmed by TGA and HRTEM studies. Thermal stability, surface morphology, and structural morphology of these materials were revealed by TGA, SEM and TEM analysis, respectively. Moreover, the tailored mesoporous Ni/KIT-6 molecular sieves were found to possess better quality and massive quantity of g-CNTs produced compared to other catalytic template route.

  7. Results of balloon atrial septostomy as preparation for surgical correction in transposition of great arteries.

    PubMed

    Padilla, Tatiana; Zapata, Margarita; Díaz, Luis Horacio; Lince, Rafael; Ruz, Miguel; Guzmán, Mónica; Donado, Juan; Franco, Gloria

    2011-04-01

    Balloon atrial septostomy (BAS) is a palliative procedure performed in the preoperative management of patients with transposition of great arteries (TGA), to improve the mixing of blood between the 2 systems. This report describes experience at the Clínica Cardiovascular Santa Maria in Medellin, Colombia. Between 2002 and 2010, 22 patients with TGA underwent BAS. Patient age at the time of the procedure was 21 days on average; 68% of patients were male. Average weight was 2.96 kg and interatrial gradient was between 4 and 12 mm Hg. The average systemic oxygen saturation at the beginning of the procedure was 60%, with a final saturation of 90%. Z5 atrioseptostomy balloons were used in 18 patients (81%), using Rashkind technique; Tyshak balloon catheters were used in 3 patients (13%) with the Shrivastava technique; and static high-pressure peripheral angioplasty balloons were used in 3 patients (13%). Two patients underwent BAS with 2 types of balloons. Although there were no complications clearly attributable to the procedure, 14% of patients had evidence of focal brain injury on the postoperative magnetic resonance image. Six patients died (27%), 5 of them because of postoperative complications and 1 because of infectious complications at another institution. All postoperative deaths occurred before 2006. The BAS is a safe technique for preoperative stabilization of patients with TGA.

  8. Hydrogen measurement during steam oxidation using coupled thermogravimetric analysis and quadrupole mass spectrometry

    DOE PAGES

    Parkison, Adam J.; Nelson, Andrew Thomas

    2016-01-11

    An analytical technique is presented with the goal of measuring reaction kinetics during steam oxidation reactions for three cases in which obtaining kinetics information often requires a prohibitive amount of time and cost. The technique presented relies on coupling thermogravimetric analysis (TGA) with a quantitative hydrogen measurement technique using quadrupole mass spectrometry (QMS). The first case considered is in differentiating between the kinetics of steam oxidation reactions and those for simultaneously reacting gaseous impurities such as nitrogen or oxygen. The second case allows one to independently measure the kinetics of oxide and hydride formation for systems in which both ofmore » these reactions are known to take place during steam oxidation. The third case deals with measuring the kinetics of formation for competing volatile and non-volatile oxides during certain steam oxidation reactions. In order to meet the requirements of the coupled technique, a methodology is presented which attempts to provide quantitative measurement of hydrogen generation using QMS in the presence of an interfering fragmentation species, namely water vapor. This is achieved such that all calibrations and corrections are performed during the TGA baseline and steam oxidation programs, making system operation virtually identical to standard TGA. Benchmarking results showed a relative error in hydrogen measurement of 5.7–8.4% following the application of a correction factor. Lastly, suggestions are made for possible improvements to the presented technique so that it may be better applied to the three cases presented.« less

  9. Drying Results of K-Basin Damaged/Corroded SNF Internal Sludge and Surface Coating

    SciTech Connect

    Abrefah, J.; Alexander, D.L.; Marschman, S.C.

    2000-09-21

    Experiments were performed using a thermogravimetric analysis (TGA) system by Pacific Northwest National Laboratory (PNNL)to study the drying behavior of the K-Basin spent nuclear fuel (SNF) internal sludge and two different surface coatings of SNF elements. These measurements were conducted in support of the safety and process analyses of the proposed Integrated Process Strategy (IPS) to move the N-Reactor fuel stored at K-Basin to an interim storage facility. These limited experiments on the corrosion products of K-Basin SNF material were part of the broad studies performed to ascertain the bounding pressurization of the Multi-Canister Overpack (MCO). Seven SNF internal sludge samples taken from different damage regions of three damaged/corroded outer K-Basin SNF elements were dried. Additionally, two surface coating samples taken from two SNF elements stored at K-West were tested. All the tests were performed in a vacuum atmosphere with the same temperature ramp rate of about 0.4 C/ min. Each TGA test sample was weighed before and after the test on a balance located in the Shielded Analytical Laboratory hot cell. The test samples were vacuum dried in the TGA system for about 24 hours prior to heating them at the rate of 0.4 C/min. The observations from the weight change data are summarized below.

  10. Synthesis and Characterization of Processable Polyaniline Salts

    NASA Astrophysics Data System (ADS)

    Gul, Salma; Shah, Anwar-ul-Haq Ali; Bilal, Salma

    2013-06-01

    Polyaniline (PANI) is one of the most promising candidates for possible technological applications. PANI has potential applications in batteries, anion exchanger, tissue engineering, inhibition of steel corrosion, fuel cell, sensors and so on. However, its insolubility in common organic solvents limits its range of applications. In the present study an attempt has been made to synthesize soluble polyaniline salt via inverse polymerization pathway using benzoyl peroxide as oxidant and dodecylbenzenesulfonic acid (DBSA) as dopant as well as a surfactant. A mixture of chloroform and 2-butanol was used as dispersion medium for the first time. The influence of synthesis parameters such as concentration of aniline, benzoyl peroxide and DBSA on the yield and other properties of the resulting PANI salt was studied. The synthesized PANI salt was found to be completely soluble in DMSO, DMF, chloroform and in a mixture of toluene and 2-propanol. The synthesized polymer salt was also characterized with cyclic voltam-metry, SEM, XRD, UV-Vis spectroscopy and viscosity measurements. TGA was used to analyze the thermal properties of synthesized polymer. The extent of doping of the PANI salt was determined from UV-Vis spectra and TGA analysis. The activation energy for the degradation of the polymer was calculated with the help of TGA.

  11. New Screening Test Developed for the Blanching Resistance of Copper Alloys

    NASA Technical Reports Server (NTRS)

    Thomas-Ogbuji, Linus U.

    2004-01-01

    NASA's extensive efforts towards more efficient, safer, and more affordable space transportation include the development of new thrust-cell liner materials with improved capabilities and longer lives. For rocket engines fueled with liquid hydrogen, an important metric of liner performance is resistance to blanching, a phenomenon of localized wastage by cycles of oxidation-reduction due to local imbalance in the oxygen-fuel ratio. The current liner of the Space Shuttle Main Engine combustion chamber, a Cu-3Ag-0.5Zr alloy (NARloy-Z) is degraded in service by blanching. Heretofore, evaluating a liner material for blanching resistance involved elaborate and expensive hot-fire tests performed on rocket test stands. To simplify that evaluation, researchers at the NASA Glenn Research Center developed a screening test that uses simple, in situ oxidation-reduction cycling in a thermogravimetric analyzer (TGA). The principle behind this test is that resistance to oxidation or to the reduction of oxide, or both, implies resistance to blanching. Using this test as a preliminary tool to screen alloys for blanching resistance can improve reliability and save time and money. In this test a small polished coupon is hung in a TGA furnace at the desired (service) temperature. Oxidizing and reducing gases are introduced cyclically, in programmed amounts. Cycle durations are chosen by calibration, such that all copper oxides formed by oxidation are fully reduced in the next reduction interval. The sample weight is continuously acquired by the TGA as usual.

  12. One-step synthesis of high quality kesterite Cu2ZnSnS4 nanocrystals - a hydrothermal approach.

    PubMed

    Tiong, Vincent Tiing; Bell, John; Wang, Hongxia

    2014-01-01

    The present work demonstrates a systematic approach for the synthesis of pure kesterite-phase Cu2ZnSnS4 (CZTS) nanocrystals with a uniform size distribution by a one-step, thioglycolic acid (TGA)-assisted hydrothermal route. The formation mechanism and the role of TGA in the formation of CZTS compound were thoroughly studied. It has been found that TGA interacted with Cu(2+) to form Cu(+) at the initial reaction stage and controlled the crystal-growth of CZTS nanocrystals during the hydrothermal reaction. The consequence of the reduction of Cu(2+) to Cu(+) led to the formation Cu2- x S nuclei, which acted as the crystal framework for the formation of CZTS compound. CZTS was formed by the diffusion of Zn(2+) and Sn(4+) cations to the lattice of Cu2- x S during the hydrothermal reaction. The as-synthesized CZTS nanocrystals exhibited strong light absorption over the range of wavelength beyond 1000 nm. The band gap of the material was determined to be 1.51 eV, which is optimal for application in photoelectric energy conversion device.

  13. One-step synthesis of high quality kesterite Cu2ZnSnS4 nanocrystals – a hydrothermal approach

    PubMed Central

    Tiong, Vincent Tiing; Bell, John

    2014-01-01

    Summary The present work demonstrates a systematic approach for the synthesis of pure kesterite-phase Cu2ZnSnS4 (CZTS) nanocrystals with a uniform size distribution by a one-step, thioglycolic acid (TGA)-assisted hydrothermal route. The formation mechanism and the role of TGA in the formation of CZTS compound were thoroughly studied. It has been found that TGA interacted with Cu2+ to form Cu+ at the initial reaction stage and controlled the crystal-growth of CZTS nanocrystals during the hydrothermal reaction. The consequence of the reduction of Cu2+ to Cu+ led to the formation Cu2− xS nuclei, which acted as the crystal framework for the formation of CZTS compound. CZTS was formed by the diffusion of Zn2+ and Sn4+ cations to the lattice of Cu2− xS during the hydrothermal reaction. The as-synthesized CZTS nanocrystals exhibited strong light absorption over the range of wavelength beyond 1000 nm. The band gap of the material was determined to be 1.51 eV, which is optimal for application in photoelectric energy conversion device. PMID:24778970

  14. Isocyanate-functionalized chitin and chitosan as gelling agents of castor oil.

    PubMed

    Gallego, Rocío; Arteaga, Jesús F; Valencia, Concepción; Franco, José M

    2013-06-03

    The main objective of this work was the incorporation of reactive isocyanate groups into chitin and chitosan in order to effectively use the products as reactive thickening agents in castor oil. The resulting gel-like dispersions could be potentially used as biodegradable lubricating greases. Three different NCO-functionalized polymers were obtained: two of them by promoting the reaction of chitosan with 1,6-hexamethylene diisocyanate (HMDI), and the other by using chitin instead of chitosan. These polymers were characterized through 1H-NMR, FTIR and thermogravimetric analysis (TGA). Thermal and rheological behaviours of the oleogels prepared by dispersing these polymers in castor oil were studied by means of TGA and small-amplitude oscillatory shear (SAOS) measurements. The evolution and values of the linear viscoelasticity functions with frequency for -NCO-functionalized chitosan- and chitin-based oleogels are quite similar to those found for standard lubricating greases. In relation to long-term stability of these oleogels, no phase separation was observed and the values of viscoelastic functions increase significantly during the first seven days of ageing, and then remain almost constant. TGA analysis showed that the degradation temperature of the resulting oleogels is higher than that found for traditional lubricating greases.

  15. Pyrolytic characteristics of biomass acid hydrolysis residue rich in lignin.

    PubMed

    Huang, Yanqin; Wei, Zhiguo; Yin, Xiuli; Wu, Chuangzhi

    2012-01-01

    Pyrolytic characteristics of acid hydrolysis residue (AHR) of corncob and pinewood (CAHR, WAHR) were investigated using a thermo-gravimetric analyzer (TGA) and a self-designed pyrolysis apparatus. Gasification reactivity of CAHR char was then examined using TGA and X-ray diffractometer. Result of TGA showed that thermal degradation curves of AHR descended smoothly along with temperature increasing from 150 °C to 850 °C, while a "sharp mass loss stage" for original biomass feedstock (OBF) was observed. Char yield from AHR (42.64-30.35 wt.%) was found to be much greater than that from OBF (26.4-19.15 wt.%). In addition, gasification reactivity of CAHR char was lower than that of corncob char, and there was big difference in micro-crystallite structure. It was also found that CAHR char reactivity decreased with pyrolysis temperature, but increased with pyrolysis heating rate and gasification temperature at 850-950 °C. Furthermore, CAHR char reactivity performed better under steam atmosphere than under CO2 atmosphere.

  16. Cloning and Functional Analysis of the Promoter of an Ascorbate Oxidase Gene from Gossypium hirsutum.

    PubMed

    Xin, Shan; Tao, Chengcheng; Li, Hongbin

    2016-01-01

    Apoplastic ascorbate oxidase (AO) plays significant roles in plant cell growth. However, the mechanism of underlying the transcriptional regulation of AO in Gossypium hirsutum remains unclear. Here, we obtained a 1,920-bp promoter sequence from the Gossypium hirsutum ascorbate oxidase (GhAO1) gene, and this GhAO1 promoter included a number of known cis-elements. Promoter activity analysis in overexpressing pGhAO1::GFP-GUS tobacco (Nicotiana benthamiana) showed that the GhAO1 promoter exhibited high activity, driving strong reporter gene expression in tobacco trichomes, leaves and roots. Promoter 5'-deletion analysis demonstrated that truncated GhAO1 promoters with serial 5'-end deletions had different GUS activities. A 360-bp fragment was sufficient to activate GUS expression. The P-1040 region had less GUS activity than the P-720 region, suggesting that the 320-bp region from nucleotide -720 to -1040 might include a cis-element acting as a silencer. Interestingly, an auxin-responsive cis-acting element (TGA-element) was uncovered in the promoter. To analyze the function of the TGA-element, tobacco leaves transformed with promoters with different 5' truncations were treated with indole-3-acetic acid (IAA). Tobacco leaves transformed with the promoter regions containing the TGA-element showed significantly increased GUS activity after IAA treatment, implying that the fragment spanning nucleotides -1760 to -1600 (which includes the TGA-element) might be a key component for IAA responsiveness. Analyses of the AO promoter region and AO expression pattern in Gossypium arboreum (Ga, diploid cotton with an AA genome), Gossypium raimondii (Gr, diploid cotton with a DD genome) and Gossypium hirsutum (Gh, tetraploid cotton with an AADD genome) indicated that AO promoter activation and AO transcription were detected together only in D genome/sub-genome (Gr and Gh) cotton. Taken together, these results suggest that the 1,920-bp GhAO1 promoter is a functional sequence with a

  17. Identification of Non-HLA Genes Associated with Celiac Disease and Country-Specific Differences in a Large, International Pediatric Cohort

    PubMed Central

    Sharma, Ashok; Liu, Xiang; Hadley, David; Hagopian, William; Liu, Edwin; Chen, Wei-Min; Onengut-Gumuscu, Suna; Simell, Ville; Rewers, Marian; Ziegler, Anette-G.; Lernmark, Åke; Simell, Olli; Toppari, Jorma; Krischer, Jeffrey P.; Akolkar, Beena; Rich, Stephen S.; Agardh, Daniel; She, Jin-Xiong

    2016-01-01

    Objectives There are significant geographical differences in the prevalence and incidence of celiac disease that cannot be explained by HLA alone. More than 40 loci outside of the HLA region have been associated with celiac disease. We investigated the roles of these non-HLA genes in the development of tissue transglutaminase autoantibodies (tTGA) and celiac disease in a large international prospective cohort study. Methods A total of 424,788 newborns from the US and European general populations and first-degree relatives with type 1 diabetes were screened for specific HLA genotypes. Of these, 21,589 carried 1 of the 9 HLA genotypes associated with increased risk for type 1 diabetes and celiac disease; we followed 8676 of the children in a 15 y prospective follow-up study. Genotype analyses were performed on 6010 children using the Illumina ImmunoChip. Levels of tTGA were measured in serum samples using radio-ligand binding assays; diagnoses of celiac disease were made based on persistent detection of tTGA and biopsy analysis. Data were analyzed using Cox proportional hazards analyses. Results We found 54 single-nucleotide polymorphisms (SNPs) in 5 genes associated with celiac disease (TAGAP, IL18R1, RGS21, PLEK, and CCR9) in time to celiac disease analyses (10−4>P>5.8x10−6). The hazard ratios (HR) for the SNPs with the smallest P values in each region were 1.59, 1.45, 2.23, 2.64, and 1.40, respectively. Outside of regions previously associated with celiac disease, we identified 10 SNPs in 8 regions that could also be associated with the disease (P<10−4). A SNP near PKIA (rs117128341, P = 6.5x10−8, HR = 2.8) and a SNP near PFKFB3 (rs117139146, P<2.8x10−7, HR = 4.9) reached the genome-wide association threshold in subjects from Sweden. Analyses of time to detection of tTGA identified 29 SNPs in 2 regions previously associated with celiac disease (CTLA4, P = 1.3x10−6, HR = 0.76 and LPP, P = 2.8x10−5, HR = .80) and 6 SNPs in 5 regions not previously

  18. An ultrasensitive SiO2-encapsulated alloyed CdZnSeS quantum dot-molecular beacon nanobiosensor for norovirus.

    PubMed

    Adegoke, Oluwasesan; Seo, Min-Woong; Kato, Tatsuya; Kawahito, Shoji; Park, Enoch Y

    2016-12-15

    Ultrasensitive, rapid and selective diagnostic probes are urgently needed to overcome the limitations of traditional probes for norovirus (NV). Here, we report the detection of NV genogroup II via nucleic acid hybridization technology using a quantum dot (QD)-conjugated molecular beacon (MB) probe. To boost the sensitivity of the MB assay system, an ultrasensitive QD fluorophore with unique optical properties was synthesized, characterized and exploited as a fluorescence signal generator. Alloyed thioglycolic (TGA)-capped CdZnSeS QDs with a high photoluminescence (PL) quantum yield (QY) value of 92% were synthesized, and a modified silanization method was employed to encapsulate the thiol-capped QDs in a silica layer. The resulting highly luminescent alloyed SiO2-coated CdZnSeS QDs had a remarkable PL QY value of 98%. Transmission electron microscopy and dynamic light scattering confirmed the monodispersity of the alloyed nanocrystals, and zeta potential analysis confirmed their colloidal stability. Powder X-ray diffraction and PL lifetime measurements confirmed the surface modification of the QDs. The alloyed TGA-capped and SiO2-coated CdZnSeS QD-conjugated MB bioprobes detected extremely low concentrations of NV RNA. Ultrasensitive detection of low concentrations of NV RNA with a limit of detection (LOD) of 8.2copies/mL in human serum and a LOD of 9.3 copies/mL in buffer was achieved using the SiO2-coated CdZnSeS QD-MB probes, an increase in sensitivity of 3-fold compared with the detection limit for NV RNA using TGA-capped CdZnSeS QD-MBs. The additional merits of our detection system are rapidity, specificity and improved sensitivity over conventional molecular test probes.

  19. Elevated PrPC expression predisposes to increased HSV-1 pathogenicity.

    PubMed

    Thackray, Alana M; Bujdoso, Raymond

    2006-01-01

    PrPC is a ubiquitously expressed glycophos-phatidylinositol-linked cell-surface glycoprotein found primarily in neural tissue. Although its normal function has not been established, there is evidence suggesting that PrPC is involved in cell signalling and cellular homeostasis. This suggests that variation in neuronal expression levels of this protein contributes towards pathogenicity induced by neurotropic agents. We have investigated the pathological response to infection with herpes simplex virus type-1 (HSV-1) in strains of mice that express different levels of PrPC. Prnp-/- mice fail to express PrPC due to an interruption in the open reading frame of the Prnp gene, whilst tg19 and tga20 mice express approximately 5 and 10 times more PrPC protein, respectively, than wild-type animals. Mice that express normal or increased levels of PrPC protein were more susceptible to acute HSV-1 infection than Prnp-/- mice. Following ear pinna inoculation with HSV-1 SC16, the order of susceptibility was tga20>tg19>wild-type>Prnp-/-. This trend was reversed when latent virus was assessed. Prnp-/- mice expressed significantly higher levels of latency-associated transcript-positive neurons in various tissues when compared with wild-type, tg19 and tga20 mice. Collectively, our data show that acute HSV-1 replication proceeds more efficiently in neuronal tissue that expresses PrPC protein and lends support to the view that this protein is involved in regulation of neurotropic viral pathogenesis. This suggests that interference of PrPC expression, or possible biochemical pathways associated with its function, may serve as an effective means of limiting the pathogenesis of acute HSV-1 infection.

  20. Edoxaban: Impact on routine and specific coagulation assays. A practical laboratory guide.

    PubMed

    Douxfils, Jonathan; Chatelain, Bernard; Chatelain, Christian; Dogné, Jean-Michel; Mullier, François

    2016-01-01

    Assessment of plasma concentration/effect of edoxaban may be useful in some situations. Also, clinicians need to know how routine coagulation assays are influenced. It was our aim to determine coagulation tests useful for the assessment of edoxaban's pharmacodynamics and provide recommendations for the interpretation of haemostasis diagnostic tests. Edoxaban was spiked at concentrations ranging from 0 to 1,000 ng/ml in platelet-poor plasma which covers the on-therapy range (from ± 25 ng/ml at Ctrough to ± 170 ng/ml at Cmax). aPTT, PT, dRVVT, chromogenic anti-Xa assays, TGA and a large panel of haemostasis diagnostic tests were performed using several reagents. A concentration-dependent prolongation of aPTT, PT and dRVVT was observed. The effect was dependent on the reagents. FXa chromogenic assays showed high sensitivity and a linear correlation depending on the methodology. TGA may be useful to assess the pharmacodynamics of edoxaban but its turnaround time and the lack of standardisation are limitations. Edoxaban impairs the assessment of lupus anticoagulant, protein S (clotting method), APC-R, antithrombin (FXa-based assay) and measurement of clotting factor activity. Immunological assays and assays acting below the FXa are not influenced by edoxaban. In conclusion, some PT reagents could be used to estimate edoxaban activity. Chromogenic anti-Xa assays are required to assess the plasma concentration. TGA may be useful but requires standardisation. In case of thrombophilia or in the exploration of a haemorrhagic event, immunological assays should be recommended, when applicable. Standardisation of the time between the last intake and the sampling is mandatory to provide a proper assessment of the result.

  1. Co-assembly of Zn(SPh){sub 2} and organic linkers into helical and zig-zag polymer chains

    SciTech Connect

    Liu Yi; Yu Lingmin; Loo, Say Chye Joachim; Blair, Richard G.; Zhang Qichun

    2012-07-15

    Two novel one-dimensional coordination polymers, single helicate [Zn(SPh){sub 2}(TPyTA)(EG)]{sub n} (EG=ethylene glycol) (1) and zig-zag structure [Zn(SPh){sub 2}(BPyVB)]{sub n} (2), were synthesized under solvothermal conditions at 150 Degree-Sign C or room temperature by the co-assembly of Zn(SPh){sub 2} and organic linkers such as 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPyTA) and 1,3-bis(trans-4-pyridylvinyl)benzene (BPyVB). X-ray crystallography study reveals that both polymers 1 and 2 crystallize in space group P2{sub 1}/c of the monoclinic system. The solid-state UV-vis absorption spectra show that 1 and 2 have maxium absorption onsets at 400 nm and 420 nm, respectively. TGA analysis indicates that 1 and 2 are stable up to 110 Degree-Sign C and 210 Degree-Sign C. - Graphical abstract: Two novel one-dimensional coordination polymers, single helicate [Zn(SPh){sub 2}(TPyTA)(EG)]{sub n} (1) and zig-zag structure [Zn(SPh){sub 2}(BPyVB)]{sub n} (2), were synthesized. Solid-state UV-vis absorptions show that 1 and 2 have maxium absorption onsets at 400 nm and 420 nm, respectively. TGA analysis indicates that 1 and 2 are stable up to 110 Degree-Sign C and 210 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Two novel one-dimensional coordination polymers have been synthesized. Black-Right-Pointing-Pointer TPyTA results in helical structures in 1 while BPyVB leads to zig-zag chains in 2. Black-Right-Pointing-Pointer Solid-state UV-vis absorption spectra and TGA analysis of the title polymers were studied.

  2. Validity of histology for the diagnosis of paediatric coeliac disease: a Swedish multicentre study.

    PubMed

    Montén, Caroline; Bjelkenkrantz, Kaj; Gudjonsdottir, Audur H; Browaldh, Lars; Arnell, Henrik; Naluai, Åsa Torinsson; Agardh, Daniel

    2016-01-01

    OBJECTIVE Histological evaluation of intestinal biopsies for the diagnosis of coeliac disease can be challenging and compatible with risk of misdiagnosis. The aim was to evaluate the agreement of pathological diagnosis for coeliac disease in children investigated at four major paediatric university hospitals in Sweden. MATERIALS AND METHODS Intestinal duodenal biopsies were collected from 402 children at median 9.7 years (1.4-18.3 years). A pathologist at each hospital performed the primary evaluation. A designated pathologist, blinded to the primary evaluation, performed a second Marsh classification of biopsies (M0 to M3c) taken from the bulb and duodenum separately. Kappa (κ) scores between first and second evaluation determined the agreement. Plasma samples were collected at the day of intestinal biopsy and analysed for tissue transglutaminase autoantibodies (tTGA) using radioligand-binding assays. RESULTS Marsh scores were concordant in 229/356 biopsies (64%, κ = 0.52, p < 0.0001). Among discordant results, 15/127 (12%) showed M0 in distal duodenum but ≥ M2 in the bulb, whereas the opposite was true for 8/127 (6%) of the biopsies. There were fewer collected duodenal biopsies, more missing bulb biopsies and missing CD3 staining among discordant evaluations. The second evaluation revealed a Marsh score compliant with coeliac disease in 22 children of whom seven children were tTGA positive. CONCLUSIONS The variation between university hospitals on the pathological evaluation of biopsies may lead to misdiagnosis of coeliac disease in paediatric patients. Access to clinical and endoscopic information as well as tTGA levels may be useful for the pathologist to complement the evaluation in dubious cases.

  3. Use of CaO as an activator for producing a price-competitive non-cement structural binder using ground granulated blast furnace slag

    SciTech Connect

    Kim, Min Sik; Jun, Yubin; Lee, Changha Oh, Jae Eun

    2013-12-15

    The use of calcium oxide (CaO) demonstrates a superior potential for the activation of ground granulated blast furnace slag (GGBFS), and it produces a higher mechanical strength than calcium hydroxide [Ca(OH){sub 2}]. The mechanical strength differences between CaO- and Ca(OH){sub 2}-activated GGBFS binders are explored using isothermal calorimetry, powder X-ray diffraction, thermogravimetric and differential thermal analysis (TGA and DTA) as well as compressive strength testing. Calcium silicate hydrate (C–S–H), Ca(OH){sub 2} and a hydrotalcite-like phase are found as reaction products in all samples. The TGA and DTA results indicate that the use of CaO produces more C–S–H, although this is not likely to be the primary cause of higher strength development in the CaO-activated GGBFS. Rather, other factors such as porosity may govern the strength at a higher order of magnitude. Significant reduction of Ca(OH){sub 2} occurs only with the use of Ca(OH){sub 2}, followed by the formation of carbonate (CaCO{sub 3}), indicating carbonation. -- Highlights: •CaO showed a better potential for the activation of GGBFS than Ca(OH){sub 2}. •Strength test, XRD, TGA/DTA and isothermal calorimetry are used. •C-S-H, Ca(OH){sub 2}, and a hydrotalcite-like phase are found in all samples. •The use of Ca(OH){sub 2} causes some degree of carbonation.

  4. High pressure/high temperature thermogravimetric apparatus. Final report

    SciTech Connect

    Calo, J.M.; Suuberg, E.M.

    1999-12-01

    The purpose of this instrumentation grant was to acquire a state-of-the-art, high pressure, high temperature thermogravimetric apparatus (HP/HT TGA) system for the study of the interactions between gases and carbonaceous solids for the purpose of solving problems related to coal utilization and applications of carbon materials. The instrument that we identified for this purpose was manufactured by DMT (Deutsche Montan Technologies)--Institute of Cokemaking and Coal Chemistry of Essen, Germany. Particular features of note include: Two reactors: a standard TGA reactor, capable of 1100 C at 100 bar; and a high temperature (HT) reactor, capable of operation at 1600 C and 100 bar; A steam generator capable of generating steam to 100 bar; Flow controllers and gas mixing system for up to three reaction gases, plus a separate circuit for steam, and another for purge gas; and An automated software system for data acquisition and control. The HP/TP DMT-TGA apparatus was purchased in 1996 and installed and commissioned during the summer of 1996. The apparatus was located in Room 128 of the Prince Engineering Building at Brown University. A hydrogen alarm and vent system were added for safety considerations. The system has been interfaced to an Ametek quadruple mass spectrometer (MA 100), pumped by a Varian V250 turbomolecular pump, as provided for in the original proposed. With this capability, a number of gas phase species of interest can be monitored in a near-simultaneous fashion. The MS can be used in a few different modes. During high pressure, steady-state gasification experiments, it is used to sample, measure, and monitor the reactant/product gases. It can also be used to monitor gas phase species during nonisothermal temperature programmed reaction (TPR) or temperature programmed desorption (TPD) experiments.

  5. Chemical coupling of thiolated chitosan to preformed liposomes improves mucoadhesive properties

    PubMed Central

    Gradauer, Kerstin; Vonach, Caroline; Leitinger, Gerd; Kolb, Dagmar; Fröhlich, Eleonore; Roblegg, Eva; Bernkop-Schnürch, Andreas; Prassl, Ruth

    2012-01-01

    Aim To develop mucoadhesive liposomes by anchoring the polymer chitosan-thioglycolic acid (chitosan-TGA) to the liposomal surface to target intestinal mucosal membranes. Methods Liposomes consisting of phosphatidylcholine (POPC) and a maleimide-functionalized lipid were incubated with chitosan-TGA, leading to the formation of a thioether bond between free SH-groups of the polymer and maleimide groups of the liposome. Uncoated and newly generated thiomer-coated liposomes were characterized according to their size, zeta potential, and morphology using photon correlation spectroscopy and transmission electron microscopy. The release behavior of calcitonin and the fluorophore/quencher-couple ANTS/DPX (8-aminonaphthalene-1,3,6-trisulfonic acid/p-xylene-bis- pyridinium bromide) from coated and uncoated liposomes, was investigated over 24 hours in simulated gastric and intestinal fluids. To test the mucoadhesive properties of thiomer-coated and uncoated liposomes in-vitro, we used freshly excised porcine small intestine. Results Liposomes showed a concentration-dependent increase in size – from approximately 167 nm for uncoated liposomes to 439 nm for the highest thiomer concentration used in this study. Likewise, their zeta potentials gradually increased from about −38 mV to +20 mV, clearly indicating an effective coupling of chitosan-TGA to the surface of liposomes. As a result of mucoadhesion tests, we found an almost two-fold increase in the mucoadhesion of coupled liposomes relative to uncoupled ones. With fluorescence microscopy, we saw a tight adherence of coated particles to the intestinal mucus. Conclusion Taken together, our current results indicate that thiomer-coated liposomes possess a high potential to be used as an oral drug-delivery system. PMID:22679365

  6. HOW DOES ANGULAR RESOLUTION AFFECT DIFFUSION IMAGING MEASURES?

    PubMed Central

    Zhan, Liang; Leow, Alex D.; Jahanshad, Neda; Chiang, Ming-Chang; Barysheva, Marina; Lee, Agatha D.; Toga, Arthur W.; McMahon, Katie L.; de Zubicaray, Greig I.; Wright, Margaret J.; Thompson, Paul M.

    2011-01-01

    A key question in diffusion imaging is how many diffusion-weighted images suffice to provide adequate signal-to-noise ratio (SNR) for studies of fiber integrity. Motion, physiological effects, and scan duration all affect the achievable SNR in real brain images, making theoretical studies and simulations only partially useful. We therefore scanned 50 healthy adults with 105-gradient high-angular resolution diffusion imaging (HARDI) at 4 Tesla. From gradient image subsets of varying size (6≤N≤94) that optimized a spherical angular distribution energy, we created SNR plots (versus gradient numbers) for seven common diffusion anisotropy indices: fractional and relative anisotropy (FA, RA), mean diffusivity (MD), volume ratio (VR), geodesic anisotropy (GA), its hyperbolic tangent (tGA), and generalized fractional anisotropy (GFA). SNR, defined in a region of interest in the corpus callosum, was near-maximal with 58, 66 and 62 gradients for MD, FA and RA in respectively, and with about 55 gradients for GA and tGA. For VR and GFA, SNR increased rapidly with more gradients. SNR was optimized when the ratio of diffusion-sensitized to non-sensitized images was 9.13 for GA and tGA, 10.57 for FA, 9.17 for RA, and 26 for MD and VR. In orientation density functions modeling the HARDI signal as a continuous mixture of tensors, the diffusion profile reconstruction accuracy rose rapidly with additional gradients. These plots may help in making trade-off decisions when designing diffusion imaging protocols. PMID:19819339

  7. Exfoliation and intercalation of montmorillonite by small peptides.

    PubMed

    Block, Karin A; Trusiak, Adrianna; Katz, Al; Alimova, Alexandra; Wei, Hui; Gottlieb, Paul; Steiner, Jeffrey C

    2015-04-01

    Understanding structural changes in clay minerals induced by complexation with organic matter is relevant to soil science and agricultural applications. In this study, the effect of peptide storage in montmorillonite and the thermal stability of peptide-clay complexes was examined through characterization by X-ray diffraction (XRD), electron microscopy, UV absorption, and thermogravimetric analysis (TGA). XRD analysis of small peptide-montmorillonite clay complexes produced profiles consisting of reflections associated with the smectite 001 reflection and related peaks similar to that produced by a mixed layer clay mineral structure. Shifts in higher order diffraction maxima were attributed to disorder caused by the intercalation with the peptides. Increasing peptide concentrations resulted in greater shifts towards smaller 2θ from 6.37° (1.39 nm) to 5.45° (1.62 nm) as the interlayer space expanded. The expansion was accompanied by broadening of the 001 reflection (FWHM increases from 0.51 to 1.22° 2θ). The XRD line broadening was interpreted as caused by poorer crystallinity resulting from intercalation and tactoid exfoliation. SEM images revealed montmorillonite platelets with upwardly rolled edges that tend toward cylindrical structures with the production of tubules. High-resolution TEM images revealed bending of montmorillonite platelets, confirming exfoliation. The distribution of basal spacings in the micrographs was determined from the spatial frequencies obtained by Fourier analysis of density profiles. The distribution indicated the presence of discrete coherent crystallite domains. XRD and TGA results indicated that higher peptide concentrations resulted in a greater fraction of intercalated peptides and that surface adsorption of peptides mediated intercalation. Therefore, higher peptide concentration led to more stable organoclay complexes. However, UV absorption and TGA found that peptide adsorption onto montmorillonite had a finite limit at

  8. Carbonic anhydrase-facilitated CO2 absorption with polyacrylamide buffering bead capture

    SciTech Connect

    Dilmore, Robert; Griffith, Craid; Liu, Zhu; Soong, Yee; Hedges, Sheila W.; Koepsel, Richard; Ataai, M

    2009-07-01

    A novel CO2 separation concept is described wherein the enzyme carbonic anhydrase (CA) is used to increase the overall rate Of CO2 absorption after which hydrated CO2 reacts with regenerable amine-bearing polyacrylamide buffering beads (PABB). Following saturation of the material's immobilized tertiary amines, CA-bearing carrier water is separated and recycled to the absorption stage while CO2-loaded material is thermally regenerated. Process application of this concept would involve operation of two or more columns in parallel with thermal regeneration with low-pressure steam taking place after the capacity of a column of amine-bearing polymeric material was exceeded. PABB CO2- bearing capacity was evaluated by thermogravimetric analysis (TGA) for beads of three acrylamido buffering monomer ingredient concentrations: 0 mol/kg bead, 0.857 mol/kg bead, and 2 mol/kg bead. TGA results demonstrate that CO2- bearing capacity increases with increasing PABB buffering concentration and that up to 78% of the theoretical CO2- bearing capacity was realized in prepared PABB samples (0.857 mol/kg recipe). The highest observed CO2-bearing capacity of PABB was 1.37 mol of CO2 per kg dry bead. TGA was also used to assess the regenerability Of CO2-loaded PABB. Preliminary results suggest that CO2 is partially driven from PABB samples at temperatures as low as 55 degrees C, with complete regeneration occurring at 100 degrees C. Other physical characteristics of PABB are discussed. In addition, the effectiveness of bovine carbonic anhydrase for the catalysis Of CO2 dissolution is evaluated. Potential benefits and drawbacks of the proposed process are discussed. Published by Elsevier Ltd.

  9. Thermal and spectral characterization of anaerobic thermal behavior patterns in a lacustrine sediment core.

    PubMed

    Guo, Fei; Mu, Yunsong; Chen, Cheng; Liao, Haiqing; Bai, Yingchen

    2016-10-01

    The thermal evolution of sedimentary organic matter is a significant mechanism in continental oil and gas formation. This study presents a new method to estimate vertical thermal evolution trends in a lake sediment core. Twenty sediment samples from a 60-cm core recovered from Lake Bosten were heated to 600 °C at a rate of 10 °C min(-1) under a N2 atmosphere. The sediments were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and then, the samples were analyzed with total organic carbon (TOC) analyses, X-ray diffraction, and (137)Cs isotopic dating techniques. Two main anaerobic thermal degradation processes were observed in the thermograms. The pyrolysis results showed variations with sediment age, with labile carbon (237.2 ± 42.98 °C) manifesting different thermogram patterns than recalcitrant carbon (498.35 ± 30.09 °C). There was a significant linear correlation between sample weight loss and TOC (r = 0.972, p < 0.001), as well as between the DSC and TGA peaks (r = 0.963, p < 0.001). As a conclusion, the thermal stability of both labile organic carbon and recalcitrant organic carbon in lacustrine sediment core increased gradually with age. These results confirm that advanced thermal techniques (DSC and TGA) operated in inert gas are potential quantitative methods to characterize the anaerobic thermal behavior of sediment organic carbon.

  10. Freedom of information applications as an "evergreening" tactic: Secretary, Department of Health and Ageing v iNOVA Pharmaceuticals (Australia) Pty Ltd (2010) 191 FCR 573; [2010] FCA 1442.

    PubMed

    Vines, Tim; Faunce, Thomas

    2011-09-01

    A recent decision of the Federal Court of Australia illustrates how patent-holding pharmaceutical companies are attempting to use Australia's Freedom of Information Act 1982 (Cth) to force Australian safety, quality and efficacy regulators to disclose whether generic competitors are attempting to enter the market. In Secretary, Department of Health and Ageing v iNova Pharmaceuticals (Australia) Pty Ltd (2010) 191 FCR 573; [2010] FCA 1442 a single judge of the Federal Court overturned a decision of the Administrative Appeals Tribunal (AAT) that would have compelled the Australian Therapeutic Goods Administration (TGA) to reveal whether they were in possession of an application to register generic versions of two iNova products: imiquimod and phentermine. In its justification to the AAT for refusing to confirm or deny the existence of any application, the TGA argued that to reveal the existence of such a document would prejudice the proper administration of the National Health Act 1953 (Cth) as it could compromise the listing of a generic on the Pharmaceutical Benefits Scheme. The AAT failed to appreciate the extent to which this revelation to a competitor would have undercut 2004 amendments to the Therapeutic Goods Act 1989 (Cth) that provided penalties for evergreening tactics involving TGA notifications to drug patent-holders and 2006 amendments to the Patents Act 1990 (Cth) which protected the right of generic manufacturers to "springboard". The decision of the Federal Court is one of the first to explore the use of freedom of information legislation by patent-holders as a potential "evergreening" technique to prolong royalties by marginalising generic competition. Because of the significant amounts of money involved in ensuring rapid market entry of low-cost generic products, the issue has considerable public health significance.

  11. Comparative Study of Stearic Acid/Iron-Oxide Binary and Stearic Acid/Iron-Oxide/Titanium-Oxide Ternary for Use as Energy Storage Material

    NASA Astrophysics Data System (ADS)

    Andiarto, Rizky; Khalish Nuryadin, Muhammad; Saleh, Rosari

    2016-04-01

    In this work, a series of stearic acid/Fe3O4, and stearic acid/Fe3O4/TiO2 nanocomposites for thermal energy storage (TES) system were synthesized through a two-step process. Fe3O4 nanoparticles and Fe3O4/TiO2 nanocomposites were first prepared using sol-gel methods and then both samples were mixed into stearic acid by dispersion technique at three different weight % ratio to stearic acid: 5%, 10% and 15% to obtain stearic acid/Fe3O4, and stearic acid/Fe3O4/TiO2 nanocomposites. Morphologies and structural properties of the samples were characterized by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDX), while thermal properties of the sample were determined by differential scanning calorimetry (DSC) and fhermogravimetric analysis (TGA). The XRD patterns demonstrate, that stearic acid/Fe3O4 contained characteristic peaks of Fe3O4 and stearic acid structures, while peaks corresponded to anatase TiO2 structures appear in stearic acid/ Fe3O4/TiO2 nanocomposites. From the DSC measurements, it is found that the maximum latent heat was found at samples with weight ratio of 5%. Moreover, the enhancement up to 20% of latent heat in solidifying as well as melting processes was observed. TGA measurements show high degradation temperature in the range of 246 - 251°C. The TGA results also shows that the residual mass of the sample matches the composition of Fe3O4 and Fe3O4/TiO2 which is added to the stearic acid.

  12. A Study on the Oxidation Behavior of Nb Alloy (Nb-1 pct Zr-0.1 pct C) and Silicide-Coated Nb Alloys

    NASA Astrophysics Data System (ADS)

    Vishwanadh, B.; Naina, R. H.; Majumdar, S.; Tewari, R.; Dey, G. K.

    2013-05-01

    In the current work, silicide coatings were produced on the Nb alloy (Nb-1 pct Zr-0.1 pct C) using the halide activated pack cementation (HAPC) technique. Coating parameters (temperature and time) were optimized to produce a two-layer (Nb5Si3 and NbSi2) coating on the Nb alloy. Subsequently, the oxidation behavior of the Nb alloy (Nb-1 pct Zr-0.1 pct C) and silicide-coated Nb alloy was studied using thermogravimetric analysis (TGA) and isothermal weight gain oxidation experiments. Phase identification and morphological examinations were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. TGA showed that the Nb alloy started undergoing accelerated oxidation at and above 773 K (500 °C). Isothermal weight gain experiments carried out on the Nb alloy under air environment at 873 K (600 °C) up to a time period of 16 hours exhibited a linear growth rate law of oxidation. In the case of silicide-based coatings, TGA showed that oxidation resistance of silicide coatings was retained up to 1473 K (1200 °C). Isothermal weight gain experiments on the silicide coatings carried out at 1273 K (1000 °C) in air showed that initially up to 8 hours, the weight of the sample increased, and beyond 8 hours the weight of the sample remained constant. The oxide phases formed on the bare samples and on the coated samples during oxidation were found to be Nb2O5 and a mixture of SiO2 and Nb2O5 phases, respectively. SEM showed the formation of nonprotective oxide layer on the bare Nb alloy and a protective (adherent, nonporous) oxide layer on silicide-coated samples. The formation of protective SiO2 layer on the silicide-coated samples greatly improved the oxidation resistance at higher temperatures.

  13. Effects of heating on fire opal and diaspore from Turkey

    NASA Astrophysics Data System (ADS)

    Hatipoǧlu, M.; Can, N.; Karali, T.

    2010-04-01

    Fire opal (SiO 2· nH 2O) and diaspore [Al(OH)O] are two different precious and rare mineral species with high water content. While these species are being cut and polished to make gems, defect-induced weaknesses such as fragility, splintering, and cracking become apparent since the temperature of the mineral species may be increased to high temperatures during the process. These deformations may be broadly related to water loss (molecular (H 2O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals. In this study, thermal properties and thermal stability as dehydratial behaviors of both gem quality fire opal (SiO 2· nH 2O) from the Şaphane region (Kütahya, Turkey) and gem quality diaspore (AlOHO) from the Milas region (Mug˘la, Turkey), including some associated mineral inclusions, were studied by means of X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform-Infrared absorption (FTIR) spectroscopy and thermal analysis (DTA/TGA). During heating to 1400 °C, DTA/TGA patterns indicated that the weight losses of the fire opal and diaspore were due to the water loss only, and that these losses occur in the temperature ranges between about 342 and 722 °C in fire opal, and between about 592 and 718 °C in diaspore. In addition, after making some corrections concerning the mass gain observed, being due to the drift with buoyancy effect of the atmosphere, in their TGA curves, the fire opal shows a mass loss of 7.942%, and one distinctive sharp endotherm at 1089.99 °C and seven weaker endotherms, whereas the diaspore shows a mass loss of about 13.826%, and one distinctive sharpest endotherm at 650.47 °C and four weaker endotherms.

  14. Thermal properties of gem-quality moganite-rich blue chalcedony

    NASA Astrophysics Data System (ADS)

    Hatipogˇlu, M.; Tuncer, Y.; Kibar, R.; Çetin, A.; Karalı, T.; Can, N.

    2010-11-01

    In this study, thermal properties and thermal decompositions of dehydration behaviour of gem-quality translucent blue chalcedonies, without banding or crystalline centre structure, from the Sarıcakaya-Eskişehir region in Turkey were studied by means of X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-AES), Fourier transform infrared (FT-IR), thermoluminescence (TL), and simultaneously two thermal analyses of (DTA/TGA) spectroscopy. X-ray diffraction patterns of the blue chalcedony indicate the presence of two important chalcedonic silica phases with overlapped peaks at 4.26, 3.34, 2.28, 2.13, 1.82, 1.54, 1.38, and 137 Å. During heating from the room temperature to 300 °C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 °C. This peak may be due to unusually high traces of the impurities S, Th, Tl, U, and W. During heating from the room temperature to 1400 °C, the TGA pattern of the blue chalcedony indicates that the weight loss is due to the silanol water loss only, and that this loss occurs in a wide temperature range between about 170 and 954 °C. In addition, after making some corrections concerning the artefact mass gain, being due to the drift with buoyancy effect of the atmosphere in its TGA curve, the moganite-rich blue chalcedony shows a relatively lower mass loss of 0.202%. The DTA pattern of the blue chalcedony displays both endothermic and exothermic behaviours because of silica phase transformations. There are one distinctive sharp endotherm and three weaker endotherms at 806 °C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 °C.

  15. Exfoliation and intercalation of montmorillonite by small peptides

    PubMed Central

    Block, Karin A.; Trusiak, Adrianna; Katz, Al; Alimova, Alexandra; Wei, Hui; Gottlieb, Paul; Steiner, Jeffrey C.

    2015-01-01

    Understanding structural changes in clay minerals induced by complexation with organic matter is relevant to soil science and agricultural applications. In this study, the effect of peptide storage in montmorillonite and the thermal stability of peptide-clay complexes was examined through characterization by X-ray diffraction (XRD), electron microscopy, UV absorption, and thermogravimetric analysis (TGA). XRD analysis of small peptide-montmorillonite clay complexes produced profiles consisting of reflections associated with the smectite 001 reflection and related peaks similar to that produced by a mixed layer clay mineral structure. Shifts in higher order diffraction maxima were attributed to disorder caused by the intercalation with the peptides. Increasing peptide concentrations resulted in greater shifts towards smaller 2θ from 6.37° (1.39 nm) to 5.45° (1.62 nm) as the interlayer space expanded. The expansion was accompanied by broadening of the 001 reflection (FWHM increases from 0.51 to 1.22° 2θ). The XRD line broadening was interpreted as caused by poorer crystallinity resulting from intercalation and tactoid exfoliation. SEM images revealed montmorillonite platelets with upwardly rolled edges that tend toward cylindrical structures with the production of tubules. High-resolution TEM images revealed bending of montmorillonite platelets, confirming exfoliation. The distribution of basal spacings in the micrographs was determined from the spatial frequencies obtained by Fourier analysis of density profiles. The distribution indicated the presence of discrete coherent crystallite domains. XRD and TGA results indicated that higher peptide concentrations resulted in a greater fraction of intercalated peptides and that surface adsorption of peptides mediated intercalation. Therefore, higher peptide concentration led to more stable organoclay complexes. However, UV absorption and TGA found that peptide adsorption onto montmorillonite had a finite limit at

  16. Manifested luminescence and magnetic responses of stoichiometry dependent Cd{sub 1− x}Mn{sub x}Se quantum dots

    SciTech Connect

    Sarma, Runjun; Deka, Geetamoni; Mohanta, Dambarudhar

    2015-02-15

    Highlights: • Thio-glycolic acid (TGA) coated Cd{sub 1−x}Mn{sub x}Se quantum dots have been prepared with varying x • Formation of QD heterostructure can be expected at a nonzero, but higher value of x. • The deep defect related emission can be attributed to V{sub Cd}–V{sub Se} di-vacancies, which is dominant for smaller values of x. • An appreciable charge transfer between Mn{sup 2+} ions and capping agent TGA is anticipated. - Abstract: We report on stoichiometry dependent manifested physical properties of thioglycolic acid (TGA) coated Cd{sub 1− x}Mn{sub x}Se QDs. While possessing a wurtzite phase, with increasing x, the QDs exhibited a notable blue-shifting of the onset of absorption. Attributed to V{sub Cd}–V{sub Se} di-vacancies, the QDs describe an intense deep-defect related emission response at smaller values of x (=0 to 0.3). Due to the facilitation of magnetic Mn{sup 2+} ion migration from the core to the QD surfaces, {sup 4}T{sub 1}–{sup 6}A{sub 1} transition based Mn{sup 2+} orange emission get suppressed at a higher x (=0.6 to 1). While the FT-IR spectra of the alloyed QDs display characteristic Mn–OH stretching mode at ∼644 cm{sup −1}, the peak located at ∼703 cm{sup −1} is assigned to Cd-Se bending. Furthermore, the QDs with a low x (=0.3), exhibit paramagnetic characteristics owing to the presence of uncorrelated, isolated Mn{sup 2+} spins. The collective luminescence and magnetic features would find immense scope in bio-labeling and imaging applications, apart from solid state luminescent components.

  17. Thermal analysis to derive energetic quality parameters of soil organic matter?

    NASA Astrophysics Data System (ADS)

    Peikert, Benjamin; Schaumann, Gabriele Ellen

    2014-05-01

    Many studies have dealt with thermal analysis for characterisation of soil and soil organic matter. It is a versatile tool assessing various physicochemical properties of the sample during heating and/or cooling. Especially the combination of different detection methods is highly promising. In this contribution, we will discuss the combination of thermogravimetry (TGA) with differential scanning calorimetry (DSC) in one single thermal analysis device. TGA alone helps distinguishment of soil and soil organic matter fractions with respect to their resistance towards combustion and allows a quantitative assignment of thermolabile and recalcitrant OM fractions. Combination with DSC in the same device, allows determination of energy transformation during the combustion process. Therefore, it becomes possible to determine not only the calorific value of the organic matter, but also of its fractions. We will show the potential of using the calorific values of OM fractions as quality parameter - exemplified for the analysis of soils polluted with organic matter from the olive oil production. The pollution history of these samples is largely unknown. As expected, TGA indicated a relative enrichment of the labile carbon fraction in contaminated samples with respect to the controls. The calorific values of the thermolabile and the recalcitrant fractions differ from each other, and those of the recalcitrant fractions of the polluted samples were higher than of those of the unpolluted controls. Further analyses showed correlation of the calorific value of this fraction with soil water repellency and the carbon isotopic ratio. The synthesis of our current data suggests that the content of thermolabile fraction, the isotopic ratio and calorific value of the recalcitrant fraction are useful indicators for characterizing the degree of decomposition of OMW organic matter. In this contribution, we will further discuss the potential of using the energetic parameters a quality

  18. Ligand exchange on the surface of cadmium telluride quantum dots with fluorosurfactant-capped gold nanoparticles: synthesis, characterization and toxicity evaluation.

    PubMed

    Wang, Lingyun; Zhang, Hongxia; Lu, Chao; Zhao, Lixia

    2014-01-01

    CdTe quantum dots (QDs) can provide high-intensity and photostable luminescent signals when they are used as labeling materials for sensing trace amounts of bioanalytes. However, a major concern is whether the capping ligands of CdTe QDs cause toxic effects in living systems. In the current study, we address this problem through the complete ligand transformation of CdTe QDs from toxic thiolglycolic acid (TGA) to green citrate, which is attributed to the Cd-S bond breaking and the Au-S bond formation. The highly efficient depletion of S atom from the surface of the CdTe QDs occurs after the addition of fluorosurfactant (FSN)-capped gold nanoparticles into TGA-capped CdTe QDs, accompanying with the rapid aggregation of FSN-capped gold nanoparticles via noncrosslinking mechanism in the presence of high salt. After the ligand transformation, negligible differences are observed on both photoluminescence spectra and luminescent quantum yield. In addition, the cytotoxicity of the original and new-born CdTe QDs is detected by measuring cell viability after the nanoparticle treatment. In comparison with the original TGA-capped QDs, the new-born CdTe QDs can induce minimal cytotoxicity against human hepatocellular liver carcinoma (HepG2) cells even at high dosages. Our study indicates that the extremely simple method herein opens up novel pathways for the synthesis of green CdTe QDs, and the as-prepared citrate-capped CdTe QDs might have great potential for biological labeling and imaging applications.

  19. Transcription promotes guanine to thymine mutations in the non-transcribed strand of an Escherichia coli gene.

    PubMed

    Klapacz, Joanna; Bhagwat, Ashok S

    2005-07-12

    Transcription of DNA opens the chromatin, causes topological changes in DNA and transiently exposes the two strands to different biochemical environments. Consequently, it has long been argued that transcription may promote damage to DNA and there are data in Escherichia coli and yeast supporting a correlation between high transcription and mutations. We examined the transcription-dependence of the reversion of a nonsense codon (TGA) in E. coli and found that there was a strong dependence of mutations on transcription in strains defective in the repair of 8-oxoguanine in DNA. Under conditions of high transcription there was a three to five-fold increase in mutations that changed TGA in the non-transcribed strand to a sense codon. Furthermore, in both mutY and mutM mutY backgrounds the mutations were overwhelmingly G:C to T:A. In contrast, when the TGA was in the transcribed strand in relation with the inducible promoter, high transcription decreased the rate of reversion. Similar results were obtained in a strain defective in the transcription-repair coupling factor, Mfd, suggesting that transcription dependent increase in base substitutions does not require transcription-dependent DNA repair. However, Mfd does modulate the magnitude of the mutagenic effect of transcription. These data are consistent with a model in which the non-transcribed strand is more susceptible to oxidative damage during transcription than the transcribed strand. These results suggest that the magnitudes of individual base substitutions and their relative numbers in other studies of mutational spectra may also be affected by transcription.

  20. Interaction of iron-copper mixed metal oxide oxygen carriers with simulated synthesis gas derived from steam gasification of coal

    SciTech Connect

    Siriwardane, Ranjani V.; Ksepko, Ewelina; Tian, Hanging

    2013-01-01

    The objective of this work was to prepare supported bimetallic Fe–Cu oxygen carriers and to evaluate their performance for the chemical-looping combustion (CLC) process with simulated synthesis gas derived from steam gasification of coal/air. Ten-cycle CLC tests were conducted with Fe–Cu oxygen carriers in an atmospheric thermogravimetric analyzer utilizing simulated synthesis gas derived from the steam gasification of Polish Janina coal and Illinois #6 coal as fuel. The effect of temperature on reaction rates, chemical stability, and oxygen transport capacity were determined. Fractional reduction, fractional oxidation, and global rates of reactions were calculated from the thermogravimetric analysis (TGA) data. The supports greatly affected reaction performance. Data showed that reaction rates and oxygen capacities were stable during the 10-cycle TGA tests for most Fe–Cu/support oxygen carriers. Bimetallic Fe–Cu/support oxygen carriers showed higher reduction rates than Fe-support oxygen carriers. The carriers containing higher Cu content showed better stabilities and better reduction rates. An increase in temperature from 800 °C to 900 °C did not have a significant effect on either the oxygen capacity or the reduction rates with synthesis gas derived from Janina coal. Oxidation reaction was significantly faster than reduction reaction for all supported Fe–Cu oxygen carriers. Carriers with higher Cu content had lower oxidation rates. Ten-cycle TGA data indicated that these oxygen carriers had stable performances at 800–900 °C and might be successfully used up to 900 °C for coal CLC reaction in the presence of steam.

  1. Chemical modification of carbon nanomaterials (SWCNTs, DWCNTs, MWCNTs and SWCNHs) with diphenyl dichalcogenides

    NASA Astrophysics Data System (ADS)

    Syrgiannis, Z.; Bonasera, A.; Tenori, E.; La Parola, V.; Hadad, C.; Gruttadauria, M.; Giacalone, F.; Prato, M.

    2015-03-01

    Control over chemical functionalization is a crucial point in the field of nanotechnology. Herein, we present the covalent functionalization of several carbon nanoforms (single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes and carbon nanohorns) by means of diphenyl dichalcogenides. These ones show different reactivity to the nanomaterials and are able to modify their electronic properties depending on the electronegativity of the functionalizing heteroatom. Theoretical calculations were also performed to support the experimental results. All the modified structured nanocarbons were thoroughly characterized by TGA Raman, XPS, UV/Vis/nIR, IR and TEM techniques. Our findings propose a simple approach to functionalize carbon nanomaterials and, in the meantime, to tune their electronic properties.Control over chemical functionalization is a crucial point in the field of nanotechnology. Herein, we present the covalent functionalization of several carbon nanoforms (single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes and carbon nanohorns) by means of diphenyl dichalcogenides. These ones show different reactivity to the nanomaterials and are able to modify their electronic properties depending on the electronegativity of the functionalizing heteroatom. Theoretical calculations were also performed to support the experimental results. All the modified structured nanocarbons were thoroughly characterized by TGA Raman, XPS, UV/Vis/nIR, IR and TEM techniques. Our findings propose a simple approach to functionalize carbon nanomaterials and, in the meantime, to tune their electronic properties. Electronic supplementary information (ESI) available: TGA, Raman spectra analysis. See DOI: 10.1039/c4nr07196d

  2. Azobenzene-based supramolecular polymers for processing MWCNTs

    NASA Astrophysics Data System (ADS)

    Maggini, Laura; Marangoni, Tomas; Georges, Benoit; Malicka, Joanna M.; Yoosaf, K.; Minoia, Andrea; Lazzaroni, Roberto; Armaroli, Nicola; Bonifazi, Davide

    2012-12-01

    Photothermally responsive supramolecular polymers containing azobenzene units have been synthesised and employed as dispersants for multi-walled carbon nanotubes (MWCNTs) in organic solvents. Upon triggering the trans-cis isomerisation of the supramolecular polymer intermolecular interactions between MWCNTs and the polymer are established, reversibly affecting the suspensions of the MWCNTs, either favouring it (by heating, i.e. cis --> trans isomerisation) or inducing the CNTs' precipitation (upon irradiation, trans --> cis isomerisation). Taking advantage of the chromophoric properties of the molecular subunits, the solubilisation/precipitation processes have been monitored by UV-Vis absorption spectroscopy. The structural properties of the resulting MWCNT-polymer hybrid materials have been thoroughly investigated via thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) and modelled with molecular dynamics simulations.Photothermally responsive supramolecular polymers containing azobenzene units have been synthesised and employed as dispersants for multi-walled carbon nanotubes (MWCNTs) in organic solvents. Upon triggering the trans-cis isomerisation of the supramolecular polymer intermolecular interactions between MWCNTs and the polymer are established, reversibly affecting the suspensions of the MWCNTs, either favouring it (by heating, i.e. cis --> trans isomerisation) or inducing the CNTs' precipitation (upon irradiation, trans --> cis isomerisation). Taking advantage of the chromophoric properties of the molecular subunits, the solubilisation/precipitation processes have been monitored by UV-Vis absorption spectroscopy. The structural properties of the resulting MWCNT-polymer hybrid materials have been thoroughly investigated via thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy

  3. Mitochondrial genome evolution in the social amoebae.

    PubMed

    Heidel, Andrew J; Glöckner, Gernot

    2008-07-01

    Most mitochondria contain a core set of genes required for mitochondrial function, but beyond this base there are variable genomic features. The mitochondrial genome of the model species Dictyostelium discoideum demonstrated that the social amoebae mitochondrial genomes have a size between those of metazoans and plants, but no comparative study of social amoebae mitochondria has been performed. Here, we present a comparative analysis of social amoebae mitochondrial genomes using D. discoideum, Dictyostelium citrinum, Dictyostelium fasciculatum, and Polysphondylium pallidum. The social amoebae mitochondria have similar sizes, AT content, gene content and have a high level of synteny except for one segmental rearrangement and extensive displacement of tRNAs. From the species that contain the rearrangement, it can be concluded that the event occurred late in the evolution of social amoebae. A phylogeny using 36 mitochondrial genes produced a well-supported tree suggesting that the pairs of D. discoideum/D. citrinum and D. fasciculatum/P. pallidum are sister species although the position of the root is not certain. Group I introns and endonucleases are variable in number and location in the social amoebae. Phylogenies of the introns and endonucleases suggest that there have been multiple recent duplications or extinctions and confirm that endonucleases have the ability to insert into new areas. An analysis of dN/dS ratios in mitochondrial genes revealed that among groups of genes, adenosine triphosphate synthase complex genes have the highest ratio, whereas cytochrome oxidase and nicotinamide adenine dinucleotide (NADH) dehydrogenase genes had the lowest ratio. The genetic codes of D. citrinum, P. pallidum, and D. fasciculatum are the universal code although D. fasciculatum does not use the TGA stop codon. In D. fasciculatum, we demonstrate for the first time that a mitochondrial genome without the TGA stop codon still uses the release factor RF2 that recognizes TGA

  4. Graphene based polyurethane material: As highly pressure sensitive composite

    NASA Astrophysics Data System (ADS)

    Hodlur, R. M.; Rabinal, M. K.

    2012-06-01

    In our present work, we describe a simple method for uniform coating of Graphite oxide (GO) onto flexible polyurethane (PU) foams. These PU foams loaded with GO were made electrically conducting by converting insulating GO to conducting graphene by chemical reduction process without damaging the foam properties. These PU foams loaded with graphene were characterized by SEM and TGA. The morphology, thermal properties and pressure dependent electrical conductivity of these foams was studied. The electric current increased by five orders of magnitude due to applied pressure.

  5. Antimicrobial hydantoin-containing polyesters.

    PubMed

    Tan, Licheng; Maji, Samarendra; Mattheis, Claudia; Zheng, Mengyao; Chen, Yiwang; Caballero-Díaz, E; Gil, Pilar Rivera; Parak, Wolfgang J; Greiner, Andreas; Agarwal, Seema

    2012-08-01

    A new N-hydantoin-containing biocompatible and enzymatically degradable polyester with antibacterial properties is presented. Different polyesters of dimethyl succinate, 1,4-butanediol, and 3-[N,N-di(β-hydroxyethyl)aminoethyl]-5,5-dimethylhydantoin in varying molar ratios are prepared via two-step melt polycondensation. The antibacterially active N-halamine form is obtained by subsequent chlorination of the polyesters with sodium hypochlorite. Chemical structures, thermal properties, and spherulitic morphologies of the copolymers are studied adopting FT-IR, NMR, TGA, DSC, WAXD, and POM. The polyesters exhibit antibacterial activity against Escherichia coli. The adopted synthetic approach can be transferred to other polyesters in a straightforward manner.

  6. Smart designing of new hybrid materials based on brushite-alginate and monetite-alginate microspheres: bio-inspired for sequential nucleation and growth.

    PubMed

    Amer, Walid; Abdelouahdi, Karima; Ramananarivo, Hugo Ronald; Fihri, Aziz; El Achaby, Mounir; Zahouily, Mohamed; Barakat, Abdellatif; Djessas, Kamal; Clark, James; Solhy, Abderrahim

    2014-02-01

    In this report new hybrid materials based on brushite-alginate and monetite-alginate were prepared by self-assembling alginate chains and phosphate source ions via a gelation process with calcium ions. The alginate served as nanoreactor for nucleation and growth of brushite or/and monetite due to its gelling and swelling properties. The alginate gel framework, the crystalline phase and morphology of formed hybrid biomaterials were shown to be strongly dependent upon the concentration of the phosphate precursors. These materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX).

  7. Solid state synthesis of tungsten carbide nanorods and nanoplatelets by a single-step pyrolysis.

    PubMed

    Shanmugam, Sangaraju; Jacob, David S; Gedanken, Aharon

    2005-10-20

    We report a simple and efficient single-step synthesis of tungsten carbide nanorods and nanoplatelets by direct pyrolysis of a hybrid composite material of 12-tungstophosphoric acid and hexadecyltrimethylammonium bromide in a closed Swagelok cell at 1000 degrees C. The product was characterized by XRD, TGA, SEM, TEM, XPS, and CV. The diameter of the nanorods is 30-50 nm, and the length varies from 200 to 500 nm. The size of the platelets is around 55 nm. The WC exhibits an interesting structural surface with kinks, steps, and terraces which is evidenced by HRTEM studies.

  8. A versatile low temperature solid-state synthesis of vanadium nitride (VN) via a "guanidinium-route": experimental and theoretical studies from the key-intermediate to the final product.

    PubMed

    de Souza, Eugenio Furtado; Chagas, Carlos Alberto; Ramalho, Teodorico C; de Alencastro, Ricardo Bicca

    2012-12-21

    An easy and efficient method ("guanidinium route") to synthesize vanadium nitride (VN) is evaluated in this paper. Initially, ammonium m-vanadate was mixed with guanidinium carbonate, producing an important intermediate, ammonium m-vanadate (GmV), through a solid-state reaction. GmV was decomposed as a function of the temperature and studied with TGA, DRX, FT-Infrared, Temperature-Programmed Surface Reaction (TPSR) and DFT. We show that GmV is transformed into bulk crystalline VN below 800 °C. XPS, periodic DFT calculations, and elemental analyses show that the surface is not carbon-free.

  9. Structural and thermal properties of γ – irradiated Bombyx mori silk fibroin films

    SciTech Connect

    Madhukumar, R.; Asha, S.; Rao, B. Lakshmeesha; Shivananda, C. S.; Harish, K. V.; Sangappa; Sarojini, B. K.; Somashekar, R.

    2015-06-24

    The gamma radiation-induced change in structural and thermal properties of Bombyx mori silk fibroin films were investigated and have been correlated with the applied radiation doses. Irradiation of samples were carried out in dry air at room temperature using Co-60 source, and radiation doses are in the range of 0 - 300 kGy. Structural and thermal properties of the irradiated silk films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) and compared with unirradiated sample. Interesting results are discussed in this report.

  10. Influence of electron irradiation on the structural and thermal properties of silk fibroin films

    SciTech Connect

    Asha, S.; Sangappa,; Sanjeev, Ganesh

    2015-06-24

    Radiation-induced changes in Bombyx mori silk fibroin (SF) films under electron irradiation were investigated and correlated with dose. SF films were irradiated in air at room temperature using 8 MeV electron beam in the range 0-150 kGy. Various properties of the irradiated SF films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Electron irradiation was found to induce changes in the physical and thermal properties, depending on the radiation dose.

  11. Phase equilibria in electrochemically oxidized La 2CuO 4δ. Transport measurements versus chemical analysis

    NASA Astrophysics Data System (ADS)

    Ondoño-Castillo, S.; Michel, C. R.; Seffar, A.; Fontcuberta, J.; Casañ-Pastor, N.

    1994-12-01

    A comparative study of physical and chemical methods for the analysis of the number and identity of holes in electrochemically oxidized La 2CuO 4+δ is reported. A combination of TGA and iodometric chemical analyses shows the existence of two species with different oxidation potentials. Susceptibility and resistivity measurements show the existence of at least two segregated superconducting phases, while Seebeck measurements shows a large change in the number of carriers for a constant value of δ; this atypical behavior is consistent though with the chemical data and implies the existence of a phase equilibrium within the oxide.

  12. Preparation and cytotoxicity of N,N,N-trimethyl chitosan/alginate beads containing gold nanoparticles.

    PubMed

    Martins, Alessandro F; Facchi, Suelen P; Monteiro, Johny P; Nocchi, Samara R; Silva, Cleiser T P; Nakamura, Celso V; Girotto, Emerson M; Rubira, Adley F; Muniz, Edvani C

    2015-01-01

    Polyelectrolyte complex beads based on N,N,N-trimethyl chitosan (TMC) and sodium alginate (ALG) were obtained. This biomaterial was characterised by FTIR, TGA/DTG, DSC and SEM analysis. The good properties of polyelectrolyte complex hydrogel beads were associated, for the first time, with gold nanoparticles (AuNPs). Through a straightforward methodology, AuNPs were encapsulated into the beads. The in vitro cytotoxicity assays on the Caco-2 colon cancer cells and healthy VERO cells showed that the beads presented good biocompatibility on both cell lines, whereas the beads loaded with gold nanoparticles (beads/AuNPs) was slightly cytotoxic on the Caco-2 and VERO cells.

  13. Physical changes associated with gamma doses on Wood/ Polypropylene Composites

    NASA Astrophysics Data System (ADS)

    Ndiaye, Diène; Tidjani, Adams

    2014-08-01

    The effect of gamma- radiation on the morphology, thermal behavior and mechanical properties of wood polypropylene composites has been investigated. Simultaneous thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been performed on WPC samples of (9.5 ± 0.1) mg. These samples were exposed to different gamma-dose in the range 10 to 100kGy. The results indicated that gamma radiation improves the mechanical properties while the thermal stability is decreased. With gamma radiation, the scanning electron microscopy (SEM) of the micrographs became smoother and we can notice an improvement of interaction between polymer and wood fibers.

  14. JPRS Report, Science & Technology, USSR: Materials Science

    DTIC Science & Technology

    2015-08-20

    consider the following geometric structure. A cone with angle a at the apex and a surface of rotation coaxial to it given by the formula Z=§(r) are...where the surface of rotation intersects the plane models the lower boundary of the parallel. Comparing (13) and (16) we obtain an equation for the...surface of rotation that ensures the required distribution of parallel 25 height: r — c r/HBmin V/» v V) — ’ — a tga [I a J

  15. The use of kinetic modelling as a fast way to screen thermal endurance of space materials

    NASA Astrophysics Data System (ADS)

    Moser, M.; Heltzel, S.; Semprimoschnig, C.; Garcia Martin, G.

    2003-09-01

    Currently planned missions of ESA (European Space Agency) to the inner part of the solar system will require the use of materials at an extreme radiation and temperature environment. A major concern regarding the selection of these materials is the thermal behaviour and the thermal stability. In this paper two kinetic models, the one following the ASTM E 1641 and ASTM E 1877 standards and the other following the Model Free Kinetics (MFK) approach, are presented. These models allow an easy and fast way to screen the thermal endurance of organic materials by running Thermo Gravimetric Analyses (TGA) temperature scans.

  16. Polyvinyl alcohol-cellulose nanofibrils-graphene oxide hybrid organic aerogels.

    PubMed

    Javadi, Alireza; Zheng, Qifeng; Payen, Francois; Javadi, Abdolreza; Altin, Yasin; Cai, Zhiyong; Sabo, Ronald; Gong, Shaoqin

    2013-07-10

    Hybrid organic aerogels consisting of polyvinyl alcohol (PVA), cellulose nanofibrils (CNFs), and graphene oxide nanosheets (GONSs) were prepared using an environmentally friendly freeze-drying process. The material properties of these fabricated aerogels were measured and analyzed using various characterization techniques including compression testing, scanning electron microscopy, thermogravimetric (TGA) analysis, Brunauer-Emmet-Teller (BET) surface area analysis, and contact angle measurements. These environmentally friendly, biobased hybrid organic aerogels exhibited a series of desirable properties including a high specific compressive strength and compressive failure strain, ultralow density and thermal conductivity, good thermal stability, and moisture resistance, making them potentially useful for a broad range of applications including thermal insulation.

  17. Interactions of CT DNA with hexagonal NaYF4 co-doped with Yb(3+)/Tm(3+) upconversion particles.

    PubMed

    Yuan, Xiuxue; Gu, Wenchao; Xiao, Mengsi; Xie, Wenli; Wei, Shaohua; Zhou, Lin; Zhou, Jiahong; Shen, Jian

    2015-02-25

    The interaction of UCPs with CT DNA are studied in detail by zeta potential, Energy dispersive spectrometer (EDS) spectroscopy, Thermogravimetric (TGA) analysis, DNA melting determination and various spectroscopic techniques including Ultraviolet-Visible (UV-Vis) absorption, fluorescence, circular dichroism (CD), Fourier transform infrared (FTIR) and Raman spectroscopy. The results indicate that CT DNA can assemble on the surface of UCPs mainly by relative stronger hydrophobic force and electrostatic binding, and the predominant interaction site is the deoxyribosyl phosphate backbone of CT DNA. Moreover, after interacting with UCPs, the double helix structure of DNA is undamaged.

  18. Hybrid combustion with metallized fuels

    NASA Technical Reports Server (NTRS)

    Yi, Jianwen; Wygle, Brian S.; Bates, Ronald W.; Jones, Michael D.; Ramohalli, Kumar

    1993-01-01

    A chemical method of adding certain catalysts to improve the degradation process of a solid fuel is discussed. Thermogravimetric (TGA) analysis used to study the fundamental degradation behavior of a typical hybrid fuel (HTPB) shows that high surface temperatures increase the degradation rate. Fuels were tested in a laboratory-scale experimental hybrid rocket and their behavior was compared to a baseline behavior of HTPB fuel regression rates. It was found that a small amount of metal powder added to the fuel can significantly increase the regression rates.

  19. Postchemoradiotherapy Positron Emission Tomography Predicts Pathologic Response and Survival in Patients With Esophageal Cancer

    SciTech Connect

    Jayachandran, Priya; Pai, Reetesh K.; Quon, Andrew; Graves, Edward; Krakow, Trevor E.; La, Trang; Loo, Billy W.; Koong, Albert C.; Chang, Daniel T.

    2012-10-01

    Purpose: To correlate the prechemoradiotherapy (CRT) and post-CRT metabolic tumor volume (MTV) on positron emission tomography (PET) scanning with the pathologic response and survival in patients receiving preoperative CRT for esophageal cancer. Materials and Methods: The medical records of 37 patients with histologically confirmed Stage I-IVA esophageal cancer treated with CRT with or without surgical resection were reviewed. Of the 37 patients, 21 received preoperative CRT (57%) and 16 received definitive CRT (43%). All patients had a pre-CRT and 32 had a post-CRT PET scan. The MTV was measured on the pre-CRT PET and post-CRT PET scan, respectively, using a minimum standardized uptake value (SUV) threshold x, where x = 2, 2.5, 3, or the SUV maximum Multiplication-Sign 50%. The total glycolytic activity (TGA{sub x}) was defined as the mean SUV Multiplication-Sign MTV{sub x}. The MTV ratio was defined as the pre-CRT PET MTV/post-CRT MTV. The SUV ratio was defined similarly. A single pathologist scored the pathologic response using a tumor regression grade (TRG) scale. Results: The median follow-up was 1.5 years (range, 0.4-4.9). No significant correlation was found between any parameters on the pre-CRT PET scan and the TRG or overall survival (OS). Multiple post-CRT MTV values and post-TGA values correlated with the TRG and OS; however, the MTV{sub 2.5Post} and TGA{sub 2.5Post} had the greatest correlation. The MTV{sub 2} ratio correlated with OS. The maximum SUV on either the pre-CRT and post-CRT PET scans or the maximum SUV ratio did not correlate with the TRG or OS. Patients treated preoperatively had survival similar compared with those treated definitively with a good PET response (p = 0.97) and significantly better than that of patients treated definitively with a poor PET response (p < 0.0001). Conclusion: The maximum SUV was not a predictive or prognostic parameter. The MTV{sub 2.5} and TGA{sub 2.5} were useful markers for predicting the response and

  20. Electrical transport and thermochromic properties of polyaniline/chitosan/Co3O4 ternary nano composite

    NASA Astrophysics Data System (ADS)

    V, Mini; Kamath, Archana; S, Raghu; Chapi, Sharanappa; H, Devendrappa

    2015-06-01

    A new Polyaniline/ chitosan/ Co3O4 (CPAESCO) ternary nanocomposite is prepared by in situ oxidation polymerization of aniline in the presence of (NH4)2S2O8, chitosan and Co3O4. The Structural, Thermal, Optical and Electrical features of Polyaniline (PANI), Polyaniline/ chitosan (CPANI) and CPAESCO were analyzed using FT-IR, TGA, UV-vis analysis and Impedance spectroscopy by varying temperature. The results show that the introduction of the Co3O4 nanoparticles into CPANI matrix enhanced its properties. Mott's parameters show 3D -VRH Type conduction in it.

  1. A polymeric flame retardant additive for rubbers

    SciTech Connect

    Ghosh, S.N.; Maiti, S.

    1993-12-31

    Synthesis of a polyphosphonate by the interfacial polymerization of bisphenol-A (BPA) and dichloro-phenyl phosphine oxide (DCPO) using cetyltrimethyl ammonium chloride (TMAC) as phase transfer catalyst (PTC) was reported. The polyphosphonate was characterized by elemental analysis, IR, TGA, DSC and 1H-NMR spectroscopy. The flame retardancy of the polymer was done by OI study. The polymer was used as a fire retardant additive to rubbers such as natural rubber (NR), styrene-butadiene rubber(SBR), nitrile rubber (NBR) and chloroprene rubber (CR). The efficiency of the fire retardant property of this additive was determined by LOI measurements of the various rubber samples.

  2. Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

    SciTech Connect

    Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

    2015-09-25

    Liquid natural rubber (LNR) with molecular weight of lower than 10{sup 5} and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

  3. Transient epileptic amnesia--a clinical update and a reformulation.

    PubMed Central

    Kapur, N

    1993-01-01

    While absence attacks and complex partial seizures have been well documented in patients with epilepsy, the delineation of pure episodes of memory loss without additional clinical manifestations remains poorly characterised. The recently described condition of transient epileptic amnesia (TEA) is critically examined, and four new cases are described, in each of which there were episodes of pure memory loss which subsequently proved to be epileptic in origin. The anatomical and pathophysiological basis of TEA is presumed to be similar to transient global amnesia (TGA), that is, it is likely to be primarily hippocampal in origin, but with more variable involvement of limbic and adjacent temporal lobe neocortical structures. PMID:8229029

  4. Effect of preparation conditions on the nanostructure of hydroxyapatite and brushite phases

    NASA Astrophysics Data System (ADS)

    Mansour, S. F.; El-dek, S. I.; Ahmed, M. A.; Abd-Elwahab, S. M.; Ahmed, M. K.

    2016-10-01

    Hydroxyapatite (HAP) and dicalcium phosphate dihydrate (brushite) nanoparticles were prepared by co-precipitation method. The obtained products were characterized by X-ray powder diffraction (XRD), Fourier transformation infra-red spectroscopy (FTIR) and thermo-gravimetric analysis (TGA). Scanning electron microscopy (SEM) and transmission electron microscope (TEM) were used to investigate the morphology of the powdered samples as well as their microstructure, respectively. Brushite samples were obtained in a spherical shape, while hydroxyapatite was formed in a needle and rice shape depending on the pH value.

  5. Synthesis and characterization of Co(II), Ni(II) and Cu(II) complexes involving hydroxy antipyrine azodyes

    NASA Astrophysics Data System (ADS)

    Gaber, M.; Hassanein, A. M.; Lotfalla, A. A.

    2008-03-01

    The complexes formed between some hydroxy antipyrine azodyes and Co(II), Ni(II) and Cu(II) ions were studied spectrophotometrically in solution. The stoichiometry and stability constants of the metal chelates were determined. The spectrophotometric determination of the titled metal ions and titration using EDTA were reported. The chelating behaviour of the azodyes was confirmed by preparing the solid chelates in which their structures are elucidated using molar conductance, elemental, thermogravimetric (TGA) analyses, IR, ESR and electronic spectra as well as the magnetic measurements. Kinetic parameters are computed from the thermal decomposition data. The electrical properties for the metal complexes are measured from which the activation energies are calculated.

  6. Effect of Added Brine on the Physico Chemical Studies of Sodium Dodecyl Sulfate and Aqueous Gelatin

    NASA Astrophysics Data System (ADS)

    George, Jinu; Sreejith, Lisa

    2011-10-01

    Effect of added brine on the structural transitions of SDS, in different compositions of gelatin has been investigated by viscosity, circular dichroism, TGA and DSC. The slow and steady growth of the normal spherical micelles to the higher order aggregates were predicted by viscosity and conductivity measurements. The large negative value for ellipticity observed from CD measurements indicated absence of any conformational change for gelatin. Other measurements were used to study the molecular packing in the micellar aggregates. The complex formed exhibits fantastic properties to be explored in the field of smart gels.

  7. PVP capped CdS nanoparticles for UV-LED applications

    SciTech Connect

    Sivaram, H.; Selvakumar, D.; Jayavel, R.

    2015-06-24

    Polyvinlypyrrolidone (PVP) capped cadmium sulphide (CdS) nanoparticles are synthesized by wet chemical method. The powder X-ray diffraction (XRD) result indicates that the nanoparticles are crystallized in cubic phase. The optical properties are characterized by UV-Vis absorption. The morphology of CdS nanoparticles are studied using Scanning electron microscope (SEM). The thermal behavior of the as prepared nanoparticles has been examined by Thermo gravimetric analysis (TGA). The optical absorption study of pvp capped CdS reveal a red shift confirms the UV-LED applications.

  8. Kinetics of Separations of Volatile Fluorides from Used Fuel Using NF3

    SciTech Connect

    Casella, Andrew M.; Scheele, Randall D.; McNamara, Bruce K.

    2011-11-01

    The study of the fluorination of UO2 with various fluorinating agents using thermogravimetric analysis (TGA) is well documented. Additional research has examined the fluorination of other metals and metal oxides. Seeing the possible benefit of using analogous fluorination technologies to affect separations in used nuclear fuel, we have expanded the existing research to an investigation of the reaction of NF3 with UO2 and NpO2. The conversion fractions gathered from experimental results have been compared with those predicted by existing models for various rate-limiting phenomena.

  9. Solvent effect in the polyethylene recovery from multilayer postconsumer aseptic packaging.

    PubMed

    Cervantes-Reyes, Alejandro; Núñez-Pineda, Alejandra; Barrera-Díaz, Carlos; Varela-Guerrero, Víctor; Martínez-Barrera, Gonzalo; Cuevas-Yañez, Erick

    2015-04-01

    Polyethylene films were separated and recovered from polyethylene-aluminum composites derived from recycling multilayer postconsumer aseptic packaging. A brief study about the separation process by dissolving PE-aluminum (PE-Al) composites into a series of organic solvents with a combination of time and temperature is presented. Through this procedure, 56% polyethylene is recovered from this kind of composites in optimized conditions. DSC and TGA studies were performed to determine the thermal stability of recovered polyethylene films and to establish a comparison with a PE reference commercial product, demonstrating that recovered polyethylene films kept their thermal properties.

  10. A simple fluorescence quenching method for berberine determination using water-soluble CdTe quantum dots as probes

    NASA Astrophysics Data System (ADS)

    Cao, Ming; Liu, Meigui; Cao, Chun; Xia, Yunsheng; Bao, Linjun; Jin, Yingqiong; Yang, Song; Zhu, Changqing

    2010-03-01

    A novel method for the determination of berberine has been developed based on quenching of the fluorescence of thioglycolic acid-capped CdTe quantum dots (TGA-CdTe QDs) by berberine in aqueous solutions. Under optimum conditions, the relative fluorescence intensity was linearly proportional to the concentration of berberine between 2.5 × 10 -8 and 8.0 × 10 -6 mol L -1 with a detection limit of 6.0 × 10 -9 mol L -1. The method has been applied to the determination of berberine in real samples, and satisfactory results were obtained. The mechanism of the proposed reaction was also discussed.

  11. A Methoxydiphenylamine-Substituted Carbazole Twin Derivative: An Efficient Hole-Transporting Material for Perovskite Solar Cells.

    PubMed

    Gratia, Paul; Magomedov, Artiom; Malinauskas, Tadas; Daskeviciene, Maryte; Abate, Antonio; Ahmad, Shahzada; Grätzel, Michael; Getautis, Vytautas; Nazeeruddin, Mohammad Khaja

    2015-09-21

    The small-molecule-based hole-transporting material methoxydiphenylamine-substituted carbazole was synthesized and incorporated into a CH3NH3PbI3 perovskite solar cell, which displayed a power conversion efficiency of 16.91%, the second highest conversion efficiency after that of Spiro-OMeTAD. The investigated hole-transporting material was synthesized in two steps from commercially available and relatively inexpensive starting reagents. Various electro-optical measurements (UV/Vis, IV, thin-film conductivity, hole mobility, DSC, TGA, ionization potential) have been carried out to characterize the new hole-transporting material.

  12. Thermodynamic analysis of volatile organometallic fission products.

    PubMed

    Auxier, John D; Jordan, Jacob A; Stratz, S Adam; Shahbazi, Shayan; Hanson, Daniel E; Cressy, Derek; Hall, Howard L

    The ability to perform rapid separations in a post nuclear weapon detonation scenario is an important aspect of national security. In the past, separations of fission products have been performed using solvent extraction, precipitation, etc. The focus of this work is to explore the feasibility of using thermochromatography, a technique largely employed in superheavy element chemistry, to expedite the separation of fission products from fuel components. A series of fission product complexes were synthesized and the thermodynamic parameters were measured using TGA/DSC methods. Once measured, these parameters were used to predict their retention times using thermochromatography.

  13. Thermal and mechanical properties of polylactic acid (PLA) and bagasse carboxymethyl cellulose (CMCB) composite by adding isosorbide diesters

    NASA Astrophysics Data System (ADS)

    Kamthai, Suthaphat; Magaraphan, Rathanawan

    2015-05-01

    An isosorbide diesters is one of isororbide types used as a plasticizer. The influence of this plasticizer on thermal and mechanical properties of polylactic acid and bagasse carboxymethyl cellulose (PLA/CMCB) composites was studied. PLA was blended with CMCB at 1%wt using various contents of isosorbide diesters (5, 10, 15 and 20%wt of PLA). The differential scanning calorimetric (DSC) and thermogravimetric (TGA) analyses indicated that the increment of isosorbide diesters concentration resulted in decreasing glass transition, melting and decomposition temperatures, as well as the reduction of storage modulus of PLA/CMCB composites. Moreover, the elongation of PLA/CMCB composites was significantly improved with increasing plasticizer content.

  14. Radiation synthesis and characterization of new hydrogels based on acrylamide copolymers cross-linked with 1-allyl-2-thiourea

    NASA Astrophysics Data System (ADS)

    Şahiner, Nurettin; Malcı, Savaş; Çelikbıçak, Ömür; Kantoğlu, Ömer; Salih, Bekir

    2005-10-01

    Poly(acrylamide-1-allyl-2-thiourea) hydrogels, Poly(AA-AT), were synthesized by gamma irradiation using 60Co γ source in different irradiation dose and at different 1-allyl-2-thiourea content in the monomer mixture. For the characterization of the hydrogels, Fourier transform infrared spectrometer (FT-IR), thermogravimetric analyzer (TGA), elemental analyzer and the swellability of the hydrogels were used. It was noted that 1-allyl-2-thiourea in the synthesized hydrogels was increased by the increasing the content of the 1-allyl-2-thiourea in the irradiation monomer mixture and increasing the radiation dose for the hydrogel synthesis.

  15. Ratiometric near infrared luminescent thermometer based on lanthanide metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Yue, Dan; Zhang, Jun; Zhao, Dian; Lian, Xiusheng; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2016-09-01

    A near infrared luminescent MOFs thermometer (Nd0.676Yb0.324BTC) was prepared via a simple solvothermal method using Ln3+ (Ln=Nd, Yb) ions and 1, 3, 5-benznenetricarboxylic acid (H3BTC), and characterized by PXRD, TGA, ICP, and photoluminescence (PL) spectrum. These results indicate that the Nd0.676Yb0.324BTC displays high relative sensitivity and excellent repeatability in the physiological temperature range (288-323 K), and the maximum relative sensitivity is determined to be 1.187% K-1 at 323 K. These NIR luminescent MOFs may have potential applications in physiological temperature sensing.

  16. Pre-irradiation induced emulsion graft polymerization of acrylonitrile onto polyethylene nonwoven fabric

    NASA Astrophysics Data System (ADS)

    Liu, Hanzhou; Yu, Ming; Deng, Bo; Li, Linfan; Jiang, Haiqing; Li, Jingye

    2012-01-01

    Acrylonitrile has been widely used in the modification of polymers by graft polymerization. In the present work, pre-irradiation induced emulsion graft polymerization method is used to introduce acrylonitrile onto PE nonwoven fabric instead of the traditional reaction in organic solvents system. The degree of grafting (DG) is measured by gravimetric method and the kinetics of the graft polymerization is studied. The existence of the graft chains is proven by Fourier transform infrared spectroscopy (FT-IR) analysis. Thermal stability of the grafted polymer is measured by Thermogravimetric analysis (TGA).

  17. Synthesis and Characterization of Lead Calcium Titanate Nanocomposite

    SciTech Connect

    Pilban, S.; Zak, A. Khorsand; Majid, W. H. Abd.; Muhamad, M. R.

    2011-03-30

    Lead calcium titanate nanoparticles (PCT-NPs) were synthesized by the modified sol-gel method. The mixed metal alkoxide precursor was prepared by moderate refluxing using lead acetate, calcium acetate, titanium iso-propoxide and 2-methoxyethanol. The properties of PCT-NPs were studied as a function of calcination temperatures. Results from the powder X-ray diffraction (XRD) and thermal analysis (TGA/DTA), indicated that the single-phase perovskite PCT-NPs were obtained after heat treatment at temperature of 700 deg. C. The average particle size of synthesized PCT-NPs was found to be around 30 nm from transition electron microscopy (TEM).

  18. Oxidation-Reduction Resistance of Advanced Copper Alloys

    NASA Technical Reports Server (NTRS)

    Greenbauer-Seng, L. (Technical Monitor); Thomas-Ogbuji, L.; Humphrey, D. L.; Setlock, J. A.

    2003-01-01

    Resistance to oxidation and blanching is a key issue for advanced copper alloys under development for NASA's next generation of reusable launch vehicles. Candidate alloys, including dispersion-strengthened Cu-Cr-Nb, solution-strengthened Cu-Ag-Zr, and ODS Cu-Al2O3, are being evaluated for oxidation resistance by static TGA exposures in low-p(O2) and cyclic oxidation in air, and by cyclic oxidation-reduction exposures (using air for oxidation and CO/CO2 or H2/Ar for reduction) to simulate expected service environments. The test protocol and results are presented.

  19. Development of Improved Printed Wiring Board Inner Layer Adhesion.

    DTIC Science & Technology

    1982-06-01

    Maleimide End Groups of Kerimid 601 82 40 The 1, 4-Dione Structure of Cured Maleimide Resin 82 41 DSC of Kerimid 601 83 42 DSC of Mica Prepreg 84 4 43 DSC of...Oak-Atlantic Prepreg 85 44 Aging Effects On the Low Temperature DSC Peaks for 87 Mica Prepreg 45 Aging Effects on Low Temperature DSC Peaks for 88...Prepreg 48 Infrared Spectrum of Norplex Polyimide 96 49 DSC Profile of Norplex Polyimide 97 * 50 TMA Profile of Norplex Polyimide 98 51 TGA Profile of

  20. New preparative methods to enhance phase purity and physical properties of cuprate superconductors

    NASA Astrophysics Data System (ADS)

    Salomon, R. E.; Schaeffer, R.; Macho, J.; Thomas, Allan; Myer, G. H.; Coppa, N. V.

    1992-04-01

    Several methods which avoid the problems inherent in solid state reactions have been developed. These methods include freeze drying, liquid ammonia based processes and a novel xerogel process. They are applicable to both 123, 124, and BISCCO based superconductors and have as their goal the atomic mixing of precursors in order to reduce inhomogeneity in the final product. The three methods are described and compared to each other and to conventional methods of synthesis. The products prepared by these methods are fully characterized by elemental analysis, XRD, TGA, DSC, resistivity and magnetic susceptibility versus temperature and by SEM.

  1. New preparative methods to enhance phase purity and physical properties of cuprate superconductors

    NASA Astrophysics Data System (ADS)

    Salomon, R. E.; Schaeffer, R.; Macho, J.; Thomas, A.; Myer, G. H.; Coppa, N. V.

    Several methods which avoid the problems inherent in solid state reactions have been developed. These methods include freeze drying, liquid ammonia based processes and a novel xerogel process. They are applicable to both 123, 124 and BISCCO based superconductors and have as their goal the atomic mixing of precursors in order to reduce inhomogeneity in the final product. The three methods are described and compared to each other and to conventional methods of synthesis. The products prepared by these methods are fully characterized by elemental analysis, XRD, TGA, DSC, resistivity and magnetic susceptibility versus temperature and by SEM.

  2. Dielectric properties of novel polyurethane/silica nanowire composites.

    PubMed

    Kim, Mu-Seong; Sekhar, Praveen K; Bhansali, Shekhar; Harmon, Julie P

    2009-10-01

    An aliphatic isocyanate, polyether, polyol thermoplastic polyurethane, Tecoflex SG-85A, was solution processed with the varying amounts of silica nanowire. The dielectric permittivity (epsilon') and loss factor (epsilon") were measured via Dielectric Analysis (DEA) in the frequency range 1 Hz to 100 kHz and between the temperature -150 to 150 degrees C. The electric modulus formalism was used to reveal alpha, beta and conductivity relaxations. The activation energies for the relaxations are presented. Nanocomposites were also characterized by differential scanning calorimetry (DSC) to determine glass transition temperatures. The onset of decomposition temperature was measured by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) provided images of the polymer-nanocomposites.

  3. Synthesis and Characterization of New Copper-Chromium Layered Double Hydroxides Pillared with Polyoxovanadates

    NASA Astrophysics Data System (ADS)

    Depège, C.; Bigey, L.; Forano, C.; de Roy, A.; Besse, J. P.

    1996-11-01

    In this study, we have focused on the intercalation by ion-exchange of some polyoxovanadate anions from aqueous solution (decavanadate V10O6-28, tetravanadate V4O4-12, and pyrovanadate V2O4-7) into the layers of a copper chromium hydrotalcite-like compound. PXRD, FTIR, TGA, and EXAFS studies have provided information about the specific oxovanadate ions in the interlayers and their orientation. Thermal treatment of these LDHs was also examined. A grafting process of pyrovanadate anions onto the hydroxylated sheets has been demonstrated at room temperature.

  4. Chemical dynamics of nano-aluminum/iodine (V) oxide

    NASA Astrophysics Data System (ADS)

    Little, B. K.; Welle, E. J.; Emery, S. B.; Bogle, M. B.; Ashley, V. L.; Schrand, A. M.; Lindsay, C. M.

    2014-05-01

    This proceeding describes our preliminary efforts in studying highly reactive composites containing crystalline iodine (V) oxide and nano-aluminum (nAl) with various amounts of cyclohexanone in the form of powders. In this study we report upon the application of physiochemical techniques such as thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), powdered X-ray diffraction (PXRD), and electron microscopy for chemical characterization of powder composites. In addition dynamic measurements were conducted by recording pressure trace profiles during a combustion event. These various techniques were employed to examine these energetic materials (EMs) and associate changes to the chemical dynamics of the composite with the additive.

  5. Preparation, characterization, and modeling of α-zirconium phosphonates with ether-functional surfaces

    PubMed Central

    Furman, Benjamin R.; Wellinghoff, Stephen T.; Thompson, Paul M.; Beall, Gary W.; Laine, Richard M.; Rawls, H. Ralph

    2009-01-01

    Layered α-zirconium(IV) phosphonates were prepared from novel ether-terminal alkyl phosphonic acids, providing nanoplatelets with brush-like polar surfaces. The precursor materials were characterized by NMR, mass spectrometry, and elemental analysis. The derived nanoparticles were examined by XRD, TEM, TGA, and elemental analysis. The experimental compositions were slightly rich in organophosphorus content. In general, the layered materials had good crystallinity, with layer reflections appearing up to (005) and d-spacings consistent with the anticipated α-phase structure. Computer simulations suggest that tailored surface chemistries, including ether functionalities, will offer favorable thermodynamic interactions with polyester polymer matrices. PMID:20090854

  6. FTIR, FT Raman and thermal studies of bisthiourea manganese chloride--an organo metallic crystal.

    PubMed

    Ramachandraraja, C; Sundararajan, R S; Krishnakumar, V

    2009-01-01

    The organometallic crystal bisthiourea manganese chloride (BTMC) was grown by slow evaporation technique using water as solvent. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. Vibrational spectra were recorded to determine the symmetries of molecular vibrations. The observed Raman and infrared bands were also assigned and discussed. The optical transmission spectral study revealed the transmitting ability of the crystal in the entire visible region. The TGA/DTA analysis explains the thermal stability of the investigated crystal.

  7. Synthesis and characterization of high temperature curable poly(arylene ether) structural adhesive and composite matrices

    SciTech Connect

    Mecham, S.J.; Jayaraman, S.; Bobbitt, M.M.

    1996-12-31

    Crosslinked poly(arylene ether) systems are projected to display many desirable properties suitable for aerospace structural adhesive and composite matrix applications. The synthesis and characterization of a series of processable high temperature curing poly(arylene ether) oligomers incorporating terminally reactive phenylethynyl endgroups will be discussed. Characterization of the oligomers includes NMR, intrinsic viscosity, parallel plate rheological behavior, TGA, and DSC. Curing of these oligomers was conducted at or above 380{degrees}C, providing a large processing window. Thermal stability is very good and the melt viscosity of the oligomers in the processing temperature range is exceptionally low.

  8. Raising the standard: changes to the Australian Code of Good Manufacturing Practice (cGMP) for human blood and blood components, human tissues and human cellular therapy products.

    PubMed

    Wright, Craig; Velickovic, Zlatibor; Brown, Ross; Larsen, Stephen; Macpherson, Janet L; Gibson, John; Rasko, John E J

    2014-04-01

    In Australia, manufacture of blood, tissues and biologicals must comply with the federal laws and meet the requirements of the Therapeutic Goods Administration (TGA) Manufacturing Principles as outlined in the current Code of Good Manufacturing Practice (cGMP). The Therapeutic Goods Order (TGO) No. 88 was announced concurrently with the new cGMP, as a new standard for therapeutic goods. This order constitutes a minimum standard for human blood, tissues and cellular therapeutic goods aimed at minimising the risk of infectious disease transmission. The order sets out specific requirements relating to donor selection, donor testing and minimisation of infectious disease transmission from collection and manufacture of these products. The Therapeutic Goods Manufacturing Principles Determination No. 1 of 2013 references the human blood and blood components, human tissues and human cellular therapy products 2013 (2013 cGMP). The name change for the 2013 cGMP has allowed a broadening of the scope of products to include human cellular therapy products. It is difficult to directly compare versions of the code as deletion of some clauses has not changed the requirements to be met, as they are found elsewhere amongst the various guidelines provided. Many sections that were specific for blood and blood components are now less prescriptive and apply to a wider range of cellular therapies, but the general overall intent remains the same. Use of 'should' throughout the document instead of 'must' allows flexibility for alternative processes, but these systems will still require justification by relevant logical argument and validation data to be acceptable to TGA. The cGMP has seemingly evolved so that specific issues identified at audit over the last decade have now been formalised in the new version. There is a notable risk management approach applied to most areas that refer to process justification and decision making. These requirements commenced on 31 May 2013 and a 12 month

  9. Advanced functionalization of organoclay nanoparticles by silylation and their polystyrene nanocomposites obtained by miniemulsion polymerization

    NASA Astrophysics Data System (ADS)

    Ianchis, R.; Corobea, M. C.; Donescu, D.; Rosca, I. D.; Cinteza, L. O.; Nistor, L. C.; Vasile, E.; Marin, A.; Preda, S.

    2012-11-01

    Four types of alkoxysilanes with different organosilyl groups were used for the silylation of a commercial alkylammonium-modified montmorillonite (Cloisite 30B). TGA, XPS, DLS, FTIR, XRD, and contact angle measurements were performed for the characterization of the silylated clays. Furthermore, the behavior of these advanced hydrophobic clays in the miniemulsion polymerization process of styrene and the characterization of nanocomposites materials were followed. The hydrophobic nature is a combined result of the length of the organic chain and of the amount of silane groups grafted onto clay edges, reflected also in the final properties of the nanocomposite latexes.

  10. Fundamental Studies on Reactive Oligomers

    DTIC Science & Technology

    1974-04-01

    compounds. The copper com- pounds reacted with BTPN-l apparently to form phthalocyanine bridges. The TGA values in air for the cured products were in...and a condenser was placed a solution of 4-chlorophenyl sulfone (5.7434 g, 0.002 mole) in a 50 ml of methyl ethyl ketone. Then sodium p-nitrophenoxide...2.95/A and 5.98/4 for the secondary amide function, as well as bands at 8.63,U and 7.57/4 for the sulfone group . This material was very soluble in

  11. Identification of a novel duplication mutation in the VHL gene in a large Chinese family with Von Hippel-Lindau (VHL) syndrome.

    PubMed

    Cao, L H; Kuang, B H; Chen, C; Hu, C; Sun, Z; Chen, H; Wang, S S; Luo, Y

    2014-12-04

    Von Hippel-Lindau (VHL) syndrome is characterized by hemangioblastomas of the brain, spinal cord, and retina, renal cysts, clear cell renal cell carcinoma, and pheochromocytoma. VHL is caused by mutations in the VHL tumor suppressor gene. We attempted to detect mutation in the VHL gene in a 5-generation Chinese family with VHL. We identified a novel small duplication that altered the reading frame downstream and created a premature TGA stop signal, resulting in severely truncated pVHL30 (p.Gly114Serfs*50) and pVHL19 (p.Gly61Serfs*50). This change was predicted to be an elongin-binding domain deletion.

  12. Safety and Characterization Tests on HIVELITE Composition 300435

    DTIC Science & Technology

    1981-02-01

    electric primer 17 2 Impact test data for HIVELITE 300435 18 3 DTA/TGA thermograms of HIVELITE 300435 19 4 Explosion temperature plot of HIVELITE 300435 20...height at which one of ten trials results in a reaction (ref 3). The results are plotted in figure 2. 2 A.- Impact Data NOL, 2.5 kg, Sandpaper 50...temperature plot of HIX’ELTF 300435 !GNITER Ashalt Paint AMP FUZE WIRE Inhibitor (PROTECTED) Figure 5. Burning rate method 21 4- Ln 3 6 Ul V- Ecr crn 1

  13. Carbon Nanotube Synthesis an Detection: Limiting the Environmental Impact of Novel Technologies

    DTIC Science & Technology

    2009-06-01

    purchased in January 2007. SWeNT, Inc. may have modified their production process between these two dates .
 
 91
 tandem analyses (e.g., TGA-MS...A., Xu, L., McNichol, A.P., Benner, B.A., Wise, S.A., Klouda, G.A., Currie, L.A.; Eglinton, T.I. Radiocarbon as a tool to apportion the sources of...and particulate matter generated during CNT manufacture and adjust synthetic conditions or improve filtration to reduce such pollution. To date

  14. Studies on thermal analysis and optical parameters of Cu doped poly(vinyl acetate)/polyindole composites

    NASA Astrophysics Data System (ADS)

    Bhagat, D. J.; Dhokane, G. R.

    2015-05-01

    This article reports investigation on optical parameters and thermal analysis of Cu doped poly(vinyl acetate)/polyindole composites using cupric chloride as an oxidant. The study's complex optical parameters were determined through ultraviolet-visible (UV-vis) spectroscopy. Thermal analysis was done through thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). The optical band gap values were found in the range 3.4381-4.8646 eV that reflects that synthesized composites have the potential to have application in optical devices and solar cells. The optical conductivity of composites is calculated to be 1.608 × 107 S-1.

  15. Synthesis of interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate: modeling and kinetics study for removal of synthetic dyes from water.

    PubMed

    Mandal, Bidyadhar; Ray, Samit Kumar

    2013-10-15

    Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied.

  16. One simple synthesis route to whisker-like nanocrystalline boron nitride by the reaction of NaBH{sub 4} and NaN{sub 3}

    SciTech Connect

    Ma Jianhua . E-mail: mjh820@ustc.edu; Li Jun; Li Guoxing; Tian Yiguang; Zhang Jing; Wu Jufeng; Zheng Jinyong; Zhuang Hemiao; Pan Tonghua

    2007-05-03

    Nanocrystalline boron nitride (BN) was synthesized via a simple route by the reaction of sodium borohydride with sodium azide in an autoclave at 600 deg. C. X-ray powder diffraction pattern indicated that the product was hexagonal BN, and the cell constant was a = 2.495 A, c = 6.687 A. Transmission electron microscopy image showed that it consisted of whisker-like particles with an average size of 200 nm x 20 nm. The product was also studied by FT-IR, XPS and TGA. It has good thermal stability and oxidation resistance in high temperature.

  17. Synthetic gene design with a large number of hidden stops.

    PubMed

    Phan, Vinhthuy; Saha, Sudip; Pandey, Ashutosh; Wong, Tit-Yee

    2010-01-01

    Hidden stops are nucleotide triples TAA, TAG and TGA that appear on the second and third reading frames of a protein coding gene. Recent studies suggested the important role of hidden stops in preventing misread of mRNA. We study the problem of designing protein-encoding genes with large number of hidden stops under several biological constraints. With simple constraints, redesigned genes have provable maximal number of hidden stops. With more complex constraints, redesigned genes still have many more hidden stops than wild-type genes. We showed that redesigned genes have a distinct positional advantage in assisting early termination of frame-shifts.

  18. Crystal growth, structure analysis and characterisation of 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid single crystal

    SciTech Connect

    Sankari, R. Siva; Perumal, Rajesh Narayana

    2014-04-24

    Single crystal of dielectric material 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid has been grown by slow evaporation solution growth method. The grown crystal was harvested in 25 days. The crystal structure was analyzed by Single crystal X - ray diffraction. UV-vis-NIR analysis was performed to examine the optical property of the grown crystal. The thermal property of the grown crystal was studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The dielectric measurements were carried out and the dielectric constant was calculated and plotted at all frequencies.

  19. Thermal Decomposition of Copper Ore Concentrate and Polyethylene Composites

    NASA Astrophysics Data System (ADS)

    Szyszka, Danuta; Wieckowska, Jadwiga

    2016-10-01

    Thermal analyses (TGA and DTA) of the composite, comprised of 10% polyethylene (PE) scrap and 90% copper ore concentrate, enabled determination of the temperature range and decomposition degree of the organic matters in argon atmosphere. Products of pyrolysis were qualitatively and quantitatively determined. The results were compared to those obtained for products of pyrolysis of the composite in air. Products of pyrolysis were identified by means of the gas chromatography (GC) method alone or supported with results of mass spectrometry analyses (GC-MS).

  20. Cu grown carbon nanofibers - Variation of their chemical and physical properties

    NASA Astrophysics Data System (ADS)

    Bhoware, Shrikant; Maubane, Manoko S.; Phaahlamohlaka, Tumelo; Shaikjee, Ahmed; Coville, Neil J.

    2013-07-01

    Carbon nanofibers (CNFs) were prepared by passing a mixture of acetylene/H2 or acetylene/N2 over different Cu catalysts. The Soxhlet extracted CNFs were characterized by TEM, TGA and IR spectroscopy and revealed that the morphology, diameter distribution and crystallinity of the CNFs varied with gas atmosphere and Cu particle size. TEM images revealed that coiled CNFs were only produced from Cu/SiO2 grown in the presence of H2. It is thus revealed that the CNFs produced by different Cu catalysts have different chemical and physical properties and that these properties correlate with catalyst particle size and the gas mixtures used.

  1. Effect of carbon black on the properties of irradiated recycled polyamide/rubber waste composites

    NASA Astrophysics Data System (ADS)

    Hassan, Medhat M.; Badway, Nagwa A.; Gamal, Azza M.; Elnaggar, Mona Y.; Hegazy, El-Sayed A.

    2010-08-01

    In the present study, the synergistic effect of carbon black (CB) content % and gamma irradiation on some mechanical, thermal, chemical stability and micro-structural properties of the moulded waste polyamide copolymer/recycled waste rubber powder (rPA/WRP) 50/50 was investigated. The ternary composites of CB concentrations, 6, 12, 18, and 24 wt.%, were irradiated with doses of 50, 100, 150 and 200 kGy. The composites mechanical properties: tensile strength, elongation at break, and hardness, and the thermal properties: melting temperature ( T m) and (Δ H) were measured. Also, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), swelling and chemical stability were investigated.

  2. Synthesis and characterization of novel main chain bisazobenzene polyphosphonates

    NASA Astrophysics Data System (ADS)

    Vlad-Bubulac, Tǎchiţǎ; Serbezeanu, Diana; Carja, Ionela-Daniela

    2016-12-01

    Preparation and experimental studies on the phase transition and morphology of novel phosphorus-containing copolymers, having bisazobenzene units and variable molar ratio of aliphatic segments in the main chain, were performed. The chemical structure of the novel compounds has been confirmed by Fourier transform infrared and 1H-NMR spectroscopy. The thermal stability was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) while the mesomorphic behavior was closely observed with polarized light microscope (PLM) and by X-ray diffraction measurements, structure-properties relationships being established and discussed.

  3. Adsorption of lead over graphite oxide.

    PubMed

    Olanipekun, Opeyemi; Oyefusi, Adebola; Neelgund, Gururaj M; Oki, Aderemi

    2014-01-24

    The adsorption efficiency and kinetics of removal of lead in presence of graphite oxide (GO) was determined using the Atomic Absorption Spectrophotometer (AAS). The GO was prepared by the chemical oxidation of graphite and characterized using FTIR, SEM, TGA and XRD. The adsorption efficiency of GO for the solution containing 50, 100 and 150 ppm of Pb(2+) was found to be 98%, 91% and 71% respectively. The adsorption ability of GO was found to be higher than graphite. Therefore, the oxidation of activated carbon in removal of heavy metals may be a viable option to reduce pollution in portable water.

  4. Selenoprotein A component of the glycine reductase complex from Clostridium purinolyticum: nucleotide sequence of the gene shows that selenocysteine is encoded by UGA.

    PubMed Central

    Garcia, G E; Stadtman, T C

    1991-01-01

    The gene encoding the selenoprotein A component of glycine reductase was isolated from Clostridium purinolyticum. The nucleotide sequence of this gene (grdA) was determined. The opal termination codon (TGA) was found in-frame at the position corresponding to the location of the selenocysteine residue in the gene product. A comparison of the nucleotide sequences and secondary mRNA structures corresponding to the selenoprotein A gene and the fdhF gene of Escherichia coli formate dehydrogenase shows that there is a similar potential for regulation of the specific insertion of selenocysteine at the UGA codon. PMID:1825826

  5. Selenoprotein A component of the glycine reductase complex from Clostridium purinolyticum: nucleotide sequence of the gene shows that selenocysteine is encoded by UGA.

    PubMed

    Garcia, G E; Stadtman, T C

    1991-03-01

    The gene encoding the selenoprotein A component of glycine reductase was isolated from Clostridium purinolyticum. The nucleotide sequence of this gene (grdA) was determined. The opal termination codon (TGA) was found in-frame at the position corresponding to the location of the selenocysteine residue in the gene product. A comparison of the nucleotide sequences and secondary mRNA structures corresponding to the selenoprotein A gene and the fdhF gene of Escherichia coli formate dehydrogenase shows that there is a similar potential for regulation of the specific insertion of selenocysteine at the UGA codon.

  6. Use of Cumulative Degradation Factor Prediction and Life Test Result of the Thruster Gimbal Assembly Actuator for the Dawn Flight Project

    NASA Technical Reports Server (NTRS)

    Lo, C. John; Brophy, John R.; Etters, M. Andy; Ramesham, Rajeshuni; Jones, William R., Jr.; Jansen, Mark J.

    2009-01-01

    The Dawn Ion Propulsion System is the ninth project in NASA s Discovery Program. The Dawn spacecraft is being developed to enable the scientific investigation of the two heaviest main-belt asteroids, Vesta and Ceres. Dawn is the first mission to orbit two extraterrestrial bodies, and the first to orbit a main-belt asteroid. The mission is enabled by the onboard Ion Propulsion System (IPS) to provide the post-launch delta-V. The three Ion Engines of the IPS are mounted on Thruster Gimbal Assembly (TGA), with only one engine operating at a time for this 10-year mission. The three TGAs weigh 14.6 kg.

  7. Synthesis and Characterization of Layered Double Hydroxides Containing Optically Active Transition Metal Ion

    NASA Astrophysics Data System (ADS)

    Tyagi, S. B.; Kharkwal, Aneeta; Nitu; Kharkwal, Mamta; Sharma, Raghunandan

    2017-01-01

    The acetate intercalated layered double hydroxides of Zn and Mn, have been synthesized by chimie douce method. The materials were characterized by XRD, TGA, CHN, IR, XPS, SEM-EDX and UV-visible spectroscopy. The photoluminescence properties was also studied. The optical properties of layered hydroxides are active transition metal ion dependent, particularly d1-10 system plays an important role. Simultaneously the role of host - guest orientation has been considered the basis of photoluminescence. Acetate ion can be exchanged with iodide and sulphate ions. The decomposed product resulted the pure phase Mn doped zinc oxide are also reported.

  8. Functionalization of Natural Graphite for Use as Reinforcement in Polymer Nanocomposites.

    PubMed

    Araujo, Rafael; Marques, Maria F V; Jonas, Renato; Grafova, Iryna; Grafov, Andriy

    2015-08-01

    Graphite is a naturally abundant material that has been used as reinforcing filler to produce polymeric nanocomposites for various applications including automotive, aerospace and electric-electronic. The objective of this study was to develop methodologies of graphite nanosheets preparation and for incorporation into polymer matrices. By means of different chemical and physical treatments, natural graphite was modified and subsequently characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetry (TGA) and the particle size determination. The results obtained clearly show that after the treatments employed, polar chemical groups were inserted on the natural graphite surface. Nanosized graphite particles of high aspect ratio were obtained.

  9. Radiation-induced grafting of acrylamide onto guar gum in aqueous medium: Synthesis and characterization of grafted polymer guar-g-acrylamide

    NASA Astrophysics Data System (ADS)

    Biswal, Jayashree; Kumar, Virendra; Bhardwaj, Y. K.; Goel, N. K.; Dubey, K. A.; Chaudhari, C. V.; Sabharwal, S.

    2007-10-01

    Mutual radiation grafting technique has been applied to carry out grafting of acrylamide (AAm) onto guar gum (GG) using high-energy Co 60γ radiation to enhance its flocculating properties for industrial effluents. The grafted product was characterized using analytical probes like elemental analysis, thermal analysis, Fourier transformed infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The grafting extent was observed to decrease with the dose rate and increase with the concentration of AAm. Thermo gravimetric analysis (TGA) of grafted and ungrafted samples indicated better stability of grafted product. γ and microwave radiation effect on grafted and virgin GG has also been reported.

  10. Monitoring Low Molecular Weight Heparins at Therapeutic Levels: Dose-Responses of, and Correlations and Differences between aPTT, Anti-Factor Xa and Thrombin Generation Assays

    PubMed Central

    Thomas, Owain; Lybeck, Emanuel; Strandberg, Karin; Tynngård, Nahreen; Schött, Ulf

    2015-01-01

    Background Low molecular weight heparins (LMWH’s) are used to prevent and treat thrombosis. Tests for monitoring LMWH’s include anti-factor Xa (anti-FXa), activated partial thromboplastin time (aPTT) and thrombin generation. Anti-FXa is the current gold standard despite LMWH’s varying affinities for FXa and thrombin. Aim To examine the effects of two different LMWH’s on the results of 4 different aPTT-tests, anti-FXa activity and thrombin generation and to assess the tests’ concordance. Method Enoxaparin and tinzaparin were added ex-vivo in concentrations of 0.0, 0.5, 1.0 and 1.5 anti-FXa international units (IU)/mL, to blood from 10 volunteers. aPTT was measured using two whole blood methods (Free oscillation rheometry (FOR) and Hemochron Jr (HCJ)) and an optical plasma method using two different reagents (ActinFSL and PTT-Automat). Anti-FXa activity was quantified using a chromogenic assay. Thrombin generation (Endogenous Thrombin Potential, ETP) was measured on a Ceveron Alpha instrument using the TGA RB and more tissue-factor rich TGA RC reagents. Results Methods’ mean aPTT at 1.0 IU/mL LMWH varied between 54s (SD 11) and 69s (SD 14) for enoxaparin and between 101s (SD 21) and 140s (SD 28) for tinzaparin. ActinFSL gave significantly shorter aPTT results. aPTT and anti-FXa generally correlated well. ETP as measured with the TGA RC reagent but not the TGA RB reagent showed an inverse exponential relationship to the concentration of LMWH. The HCJ-aPTT results had the weakest correlation to anti-FXa and thrombin generation (Rs0.62–0.87), whereas the other aPTT methods had similar correlation coefficients (Rs0.80–0.92). Conclusions aPTT displays a linear dose-respone to LMWH. There is variation between aPTT assays. Tinzaparin increases aPTT and decreases thrombin generation more than enoxaparin at any given level of anti-FXa activity, casting doubt on anti-FXa’s present gold standard status. Thrombin generation with tissue factor-rich activator is

  11. Characterization of Poly(ether)urethanes - High Resolution Thermogravimetric Analysis

    DTIC Science & Technology

    2004-02-01

    temperature is held constant until the rate of weight loss falls below a predetermined rate. Heating is then resumed until the rate of weight loss...TGA) is a technique where the weight loss of a sample is monitored at constant temperature or as temperature is scanned. It is known that plastic...thermogravimétrique (ATG) est une technique qui permet de suivre la perte de poids d’un échantillon à une température constante ou en fonction d’une variation de

  12. Interaction of hydrogen chloride with alumina. [influence of outgas and temperature conditions on adsorption

    NASA Technical Reports Server (NTRS)

    Bailey, R. R.; Wightman, J. P.

    1975-01-01

    The influence of outgas conditions and temperature on the adsorptive properties of two aluminas Alon-c and Al6sG were studied using adsorption isotherm measurements. Alon-C and Al6SG were characterized using X-ray powder diffraction, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and BET nitrogen surface areas. Some of these techniques were applied to two other aluminas but no isotherm data was obtained. Isotherm data and techniques applied to each alumina are summarized in tabular form.

  13. DBAR investigation on films of polypyrrole incorporated polyvinylalcohol doped with ferric chloride

    NASA Astrophysics Data System (ADS)

    Lobo, Blaise; Baraker, B. M.; Hammannavar, P. B.; Bhajantri, R. F.; Ranganath, M. R.; Hurkadli, M.; Ravindrachary, V.

    2015-06-01

    Flexible films of pyrrole(Py) sorbed, ferric chloride (FeCl3) doped polyvinylalcohol(PVA) were prepared by solution casting. The films were characterized by XRD, UV-Visible spectrometry, Thermal Analysis (DSC, DTA/TGA), FTIR and electrical measurements. In this paper, the results of Doppler Broadening of Annihilation Radiation (DBAR) spectra in the doping range, from 4 wt% up to 18 wt%, are discussed. The XRD and DSC scans complement the DBAR results. The computed S- parameter and W -parameter reflect changes in the degree of crystallinity and the average crystallite size, respectively, of polypyrrole(PPy) incorporated PVA samples doped with ferric chloride.

  14. LAB-SCALE DEMONSTRATION OF PLUTONIUM PURIFICATION BY ANION EXCHANGE, PLUTONIUM (IV) OXALATE PRECIPITATION, AND CALCINATION TO PLUTONIUM OXIDE TO SUPPORT THE MOX FEED MISSION

    SciTech Connect

    Crowder, M.; Pierce, R.

    2012-08-22

    presence of oxalate by thermogravimetric analysis-mass spectrometry (TGA-MS). To use the TGA-MS for carbon or oxalate content, some method development will be required. However, the TGA-MS is already used for moisture measurements. Therefore, SRNL initiated method development for the TGA-MS to allow quantification of oxalate or total carbon. That work continues at this time and is not yet ready for use in this study. However, the collected test data can be reviewed later as those analysis tools are available.

  15. Preparation and luminescent properties of GdOF:Ce, Tb nanoparticles and their transparent PMMA nanocomposites

    NASA Astrophysics Data System (ADS)

    Cai, Wen; Wang, Aiwu; Fu, Li; Hu, Jie; Rao, Tingke; Wang, Junqing; Zhong, Jiasong; Xiang, Weidong

    2015-05-01

    GdOF:Ce, Tb nanoparticles and their poly (methyl methacrylate) (PMMA) nanocomposites have been successfully prepared by a thermolysis route and thermal polymerization of methyl methacrylate (MMA) monomer, respectively. The obtained nanoparticles and nanocomposites are characterized by XRD, EDS, TEM, FTIR, TGA, UV-Vis and PL spectrum. The as-synthesized transparent GdOF:Ce, Tb/PMMA nanocomposites exhibit green photoluminescence under the irradiation of 254 nm UV lamp due to the incorporation of luminescent GdOF:Ce, Tb nanoparticles into the PMMA matrix. The present route would provide a general strategy to prepare other functional nanocomposites.

  16. Preparation and properties of photo-crosslinkable hydrogel based on photopolymerizable chitosan derivative.

    PubMed

    Qi, Zaiqian; Xu, Juan; Wang, Zhiliang; Nie, Jun; Ma, Guiping

    2013-02-01

    Photopolymerizable chitosan derivative was synthesized by chitosan and methyl acroloyl glycine (MAG). The chemical structures and physical properties were characterized by FT-IR, (1)H NMR, XRD and TGA. The thermal stability of chitosan derivative was lower than chitosan. The chitosan derivative was amorphous compared with the high degree crystallization of chitosan. The hydrogels were prepared based on chitosan derivative via photopolymerization with different concentrations of photoinitiator 2959. The surface of hydrogel showed porous network and the pore size distribution tended to become homogeneous with the increase of the concentration of 2959, while the swelling property decreased due to more crosslinking.

  17. Synthesis and characterization of chitosan-based hydrogels.

    PubMed

    Li, Qianzhu; Yang, Dongzhi; Ma, Guiping; Xu, Qiang; Chen, Xiangmei; Lu, Fengmin; Nie, Jun

    2009-03-01

    Biocompatible hydrogels based on water-soluble chitosan-ethylene glycol acrylate methacrylate (CS-EGAMA) and polyethylene glycol diamethacrylate (PEGDMA) were synthesized by photopolymerization. Characterization of morphology, weight loss, water state of hydrogel, pH-sensitivity and cytotoxicity were investigated by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), swelling test and methylthiazolydiphenyl-tetrazolium bromide (MTT) assay. The results indicated that the hydrogels were sensitive to pH of the medium, no cytotoxicity for L929 and SW1353, satisfactory for the composite to be used in bioapplications.

  18. Synthesis, characterization and thermal sensitivity of chitosan-based graft copolymers.

    PubMed

    Kang, Hong-Mei; Cai, Yuan-Li; Liu, Peng-Sheng

    2006-12-11

    Novel chitosan-based graft copolymers (CECTS-g-PDMA) were synthesized through homogeneous graft copolymerization of (N,N-dimethylamino)ethyl methacrylate (DMA) onto N-carboxyethylchitosan (CECTS) in aqueous solution by using ammonium persulfate (APS) as the initiator. The effect of polymerization variables, including initiator concentration, monomer concentration, reaction time and temperature, on grafting percentage was studied. XRD, FTIR, DSC and TGA were used to characterize the graft copolymers. Surface-tension measurements, turbidity measurements and temperature-variable (1)H NMR analysis were combined to investigate the thermal sensitivity of CECTS-g-PDMAs in aqueous solution.

  19. Oxidation of Chemically-Vapor-Deposited Silicon Carbide in Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Nguyen, QuynhGiao N.

    1998-01-01

    Chemically-vapor-deposited silicon carbide (CVD SiC) was oxidized in carbon dioxide (CO2) at temperatures of 1200-1400 C for times between 96 and 500 h at several gas flow rates. Oxidation weight gains were monitored by thermogravimetric analysis (TGA) and were found to be very small and independent of temperature. Possible rate limiting kinetic mechanisms are discussed. Passive oxidation of SiC by CO2 is negligible compared to the rates measured for other oxidants that are also found in combustion environments, oxygen and water vapor.

  20. Paralinear Oxidation of CVD SiC in Water Vapor

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Hann, Raiford E., Jr.

    1997-01-01

    The oxidation kinetics of CVD SiC were monitored by thermogravimetric analysis (TGA) in a 50% H2O/50% O2 gas mixture flowing at 4.4 cm/s for temperatures between 1200 and 1400 C. Paralinear weight change kinetics were observed as the water vapor oxidized the SiC and simultaneously volatilized the silica scale. The long-term degradation rate of SiC is determined by the volatility of the silica scale. Rapid SiC surface recession rates were estimated from these data for actual aircraft engine combustor conditions.