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Sample records for bisulfates

  1. Stable Ammonium Bisulfate Clusters in the Atmosphere

    Science.gov (United States)

    Vehkamäki, Hanna; Napari, Ismo; Kulmala, Markku; Noppel, Madis

    2004-09-01

    Liquid drop model based equilibrium thermodynamics predicts that in the presence of even small ammonia concentrations practically all the atmospheric sulfuric acid molecules are bound to tiny, stable ammonium-bisulfate clusters. Hitherto sulfuric acid has been believed to form hydrates with water. Thermodynamic theory predicts correctly the hydrate formation observed experimentally. Results from ab initio computer simulations contradict the thermodynamic results and also the experimental findings for cluster formation in both sulfuric acid-water and ammonia-sulfuric acid-water mixtures.

  2. Synthesis and Characterization of Highly Intercalated Graphite Bisulfate

    Science.gov (United States)

    Salvatore, Marcella; Carotenuto, Gianfranco; De Nicola, Sergio; Camerlingo, Carlo; Ambrogi, Veronica; Carfagna, Cosimo

    2017-03-01

    Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtained graphite intercalation compounds have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), micro-Raman spectroscopy ( μ-RS), and thermal analysis (TGA). Delamination and pre-expansion phenomena were observed only for nitric acid, sodium chlorate, and hydrogen peroxide, while the presence of strong oxidizers (KMnO4, K2Cr2O7) led to stable graphite intercalation compounds. The largest content of intercalated bisulfate is achieved in the intercalated compounds obtained from NaIO4 and NaClO3.

  3. Fragmentation and Growth Energetics of Ammonium Bisulfate Clusters Relevant to Atmospheric New Particle Formation

    Science.gov (United States)

    Bzdek, B. R.; DePalma, J.; Ridge, D. P.; Laskin, J.; Johnston, M. V.

    2012-12-01

    New particle formation (NPF) may significantly impact cloud albedo and global climate by influencing cloud condensation nuclei levels. The climate effects of NPF are governed by both the nucleation of new clusters and their growth to larger sizes. A firm understanding of the chemical mechanisms of small cluster growth to larger sizes is required to accurately model NPF. However, experimental measurements of the energetics of cluster growth are challenging. This presentation discusses results obtained using a new approach to studying cluster growth, by making measurements of cluster dissociation and inferring growth from the inverse process. In this work, the fragmentation energetics of positively charged ammonium bisulfate clusters of the form [(NH4)x(HSO4)x-1]+ were studied using a 6T Fourier transform ion cyclotron resonance mass spectrometer equipped with surface induced dissociation (SID), a method to fragment ions by impacting them on a surface at a precisely known collision energy. An ammonium bisulfate cluster was isolated and then fragmented by SID. Fragmentation efficiency curves were plotted as a function of collision energy and were fit to a Rice-Ramsperger-Kassel-Marcus/Quasi-Equilibrium Theory (RRKM/QET) model in order to extract threshold energies for dissociation. Two pathways exist for fragmentation of positively charged ammonium bisulfate clusters. The first is a one-step fragmentation pathway whereby the cluster loses an ammonium bisulfate molecule, [(NH4)(HSO4)]. The second fragmentation pathway is a two-step pathway, whereby the cluster first loses an ammonia molecule and next loses a sulfuric acid molecule. Assuming that cluster growth mechanisms are the reverse of cluster dissociation mechanisms, these observations suggest two potential growth pathways for ammonium bisulfate clusters: 1) growth by addition of an ammonium bisulfate molecule to a preexisting cluster and 2) stepwise growth by sequential addition of a sulfuric acid molecule

  4. Prediction and mitigation of air preheater fouling due to ammonium bisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, R.; Tavoulareas, S.; Stallings, J. [Energy and Environmental Strategies, MA (United States)

    2001-07-01

    This paper provides a brief review of the fundamentals of ammonium bisulfate (ABS) formation, deposition and fouling in the air preheater. It presents a software-based predictive model for assessing the potential for air preheater fouling as a result of proposed SNCR or SCR retrofits and considering site-specific conditions and introduces a software-based cost-benefit model for assessing the economic trade-offs of various ABS fouling mitigation options. 7 refs., 13 figs.

  5. Influence of microenvironment pH, humidity, and temperature on the stability of polymorphic and amorphous forms of clopidogrel bisulfate

    DEFF Research Database (Denmark)

    Raijada, Dhara K; Singh, Saranjit; Bansal, Arvind K

    2010-01-01

    The effect of microenvironment pH, humidity, and temperature was evaluated on the stability of polymorphic and amorphous forms of clopidogrel bisulfate, when present alone or in combinations. Oxalic acid and sodium carbonate were used as solid stressors to create acidic and alkaline pH, respectiv......The effect of microenvironment pH, humidity, and temperature was evaluated on the stability of polymorphic and amorphous forms of clopidogrel bisulfate, when present alone or in combinations. Oxalic acid and sodium carbonate were used as solid stressors to create acidic and alkaline p...... salt to free base. Thermal studies indicated that polymorphic forms of clopidogrel bisulfate and also its glassy amorphous form were highly resistant to temperature, whereas the rubbery state of the drug degraded significantly at temperatures of > or =80 degrees C....

  6. A Study of Bisulfate Adsorption on PT(111) Single Crystal Electrodes Using In-situ Fourier Transform Infrared Spectroscopy

    Science.gov (United States)

    1989-08-10

    for the S04 2 - anion are taken from IR data for aqueous solutions.8 The C3v symmetry group for the HS04 " anion is arrived at by treating the...hydroxyl moiety as a point mass 9 , and the peak positions are representative of HS04 " in aqueous solution and in crystal hydrates.9 ,l0 There are five...are the symmetric stretch of bisulfate, vs(HS0 4-), at -1050 cm 1 , the double degenerate asymmetric stretch of bisulfate, vas( HS04 ") and the triply

  7. Chromatographic determination of clopidogrel bisulfate; detection and quantification of counterfeit Plavix® tablets

    Directory of Open Access Journals (Sweden)

    Mona E. ElTantawy

    2014-06-01

    Full Text Available Counterfeiting of pharmaceutical products is a global problem. Upon using quality-ensuring methods of international pharmacopoeias, additional impurities and the low content of the active pharmaceutical ingredients were detected. In this paper, two chromatographic HPLC and TLC-densitometric methods were proposed as fast and reliable methods for detection and quantitation of counterfeit Plavix® tablets. These tablets were chemically counterfeited by aspirin, its degradate salicylic acid and metronidazole which were separated, besides the active ingredient clopidogrel bisulfate, by the proposed methods. Also, counterfeit was in packaging, strips and tablets’ color and these could be seen by visual inspection compared to original drug. The proposed methods can easily differentiate genuine from counterfeited tablets without need of prior separation. The proposed methods were validated according to ICH guidelines and applied to eleven batches, also were compared statistically with the reported one.

  8. In Situ Fourier Transform Infrared Spectroscopic Study of Bisulfate and Sulfate Adsorption on Gold, With and Without the Underpotential Deposition of Copper

    Science.gov (United States)

    1993-04-01

    fleta Entered) In situ surface infrared (IR) spectroelectrochemistry is used to investigate the adsorption of sulfate (SO42 ") and bisulfate ( HS04 ) ions...IR) spectroelectrochemistry is used to investigate the adsorption of sulfate (SO42-) and bisulfate ( HS04 -) ions on polycrystalline gold surfaces in...asymmetric stretch) peak (Figure 7) suggest that for predominantly acidic solutions, HS04 - is lost from the surface as the potential is increased. On

  9. Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater

    Energy Technology Data Exchange (ETDEWEB)

    J. Menasha; D. Dunn-Rankin; L. Muzio; J. Stallings [University of California Irvine, Irvine, CA (United States). Department of Mechanical and Aerospace Engineering

    2011-07-15

    Ammonium bisulfate (ABS) forms in coal-fired power plant exhaust systems when ammonia slip from the NOx control system reacts with the sulfur oxides and water in the flue gas. The critical temperature range for ABS formation occurs in the air preheater, where ABS is known to cause corrosion and pluggage that can require unplanned outages and expensive cleaning. To develop mitigation strategies for the deleterious effects of ABS in air preheaters, it is important to know its formation temperature and deposition process. This paper describes a bench-scale experimental simulation of a single-channel air preheater, with the appropriate temperature gradient, used in conjunction with simulated coal combustion flue gas, including sulfur oxides, ammonia, and water vapor, to investigate the formation of ABS. Formation was observed optically, and the formation temperature, as well as deposition characteristics for a realistic range of reactant concentrations are presented and compared with previous studies on ABS formation. This study presents data at realistic concentrations not earlier tested, and the reported data has smaller experimental uncertainty than previously obtained. We found that the measured ABS formation temperatures under air preheater channel conditions lies between the temperatures reported by others, and is in the range of 500-520 K for typical flue gas concentrations of ammonia and sulfur oxide species. The results also show that, at least for this experimental configuration, ABS forms predominantly as an aerosol in the gas phase rather than as a condensate on the channel walls. 13 refs., 13 figs., 2 tabs.

  10. Andrographolide Sodium Bisulfate Prevents UV-Induced Skin Photoaging through Inhibiting Oxidative Stress and Inflammation

    Directory of Open Access Journals (Sweden)

    Janis Ya-Xian Zhan

    2016-01-01

    Full Text Available Andrographolide sodium bisulfate (ASB, a water-soluble form made from andrographolide through sulfonating reaction, is an antioxidant and anti-inflammatory drug; however, the antiphotoaging effect of ASB has still not been revealed. Oxidative stress and inflammation are known to be responsible for ultraviolet (UV irradiation induced skin damage and consequently premature aging. In this study, we aimed at examining the effect of ASB on UV-induced skin photoaging of mice by physiological and histological analysis of skin and examination of skin antioxidant enzymes and immunity analyses. Results showed that topical administration of ASB suppressed the UV-induced skin thickness, elasticity, wrinkles, and water content, while ASB, especially at dose of 3.6 mg/mouse, increased the skin collagen content by about 53.17%, decreased the epidermal thickness by about 41.38%, and prevented the UV-induced disruption of collagen fibers and elastic fibers. Furthermore, ASB decreased MDA level by about 40.21% and upregulated the activities of SOD and CAT and downregulated the production of IL-1β, IL-6, IL-10, and TNF-α in UV-irradiated mice. Our study confirmed the protective effect of ASB against UV-induced photoaging and initially indicated that this effect can be attributed to its antioxidant and anti-inflammatory activities in vivo, suggesting that ASB may be a potential antiphotoaging agent.

  11. Design and Development of Clopidogrel Bisulfate Gastroretentive Osmotic Formulation Using Quality by Design Tools.

    Science.gov (United States)

    Desai, Nilesh; Purohit, Ravindra

    2017-02-28

    Clopidogrel bisulfate (CBS) is antiplatelet drug and it is becoming a drug of choice in the treatment and management of prevention of heart attacks and strokes. CBS is stable and soluble in acidic pH; therefore, retention in stomach for prolonged period appears to be beneficial for controlling the bioavailability. The gastroretentive osmotic system (GROS) facilitates prolonged retention of drug in stomach and provides zero-order drug release. A complex formulation like GROS poses many challenges, and QbD tools can help in designing robust formulation which takes all aspects of product and process development in order to deliver a robust product. The GROS was formulated in three steps: core tablet, osmotic tablet, and gastroretentive osmotic tablet. The design of experiment was used for screening and optimization of formulation and process-related parameters. The dissolution study was carried out to analyze the release pattern of tablet. The optimized batch O-4 showed cumulative drug release of 19.43, 30.49, 64.41, and 85.11% at 2, 4, 8, and 12 h which is in the range of QTPP predictions. The novel technique of GROS was implemented successfully which demonstrates robust design giving consistent and desired results.

  12. COST-MINIMIZATION ANALYSIS OF VARIOUS PHARMACEUTICAL ALTERNATIVES OF CLOPIDOGREL BISULFATE

    Directory of Open Access Journals (Sweden)

    Ahmad Yahya

    2016-01-01

    Full Text Available Heart disease is widespread, and accounts for a quarter of all deaths in the US. Clopidogrel is used extensively for various cardiac conditions but has a high price. Cost-minimization analysis (CMA differentiates alternative therapies based on price, given that all of the interventions have exactly the same health effects and must be bioequivalent when it comes to health benefits and adverse effects. Dissolution studies, using four marketed products, were conducted using a six stage, type II dissolution apparatus. Samples were analyzed at 240nm using a UV-VIS spectrophotometer. Concentration values of each sample, taken after 30 minutes were calculated from the calibration curve constructed with Clopidogrel Bisulfate RS. ANOVA was used to analyze any significant differences between the means of active dissolved. Plavix was found to have the highest percentage release of 97% but Ogrel had the least SEM of 3.9 with a percentage release of 95%. Lowplat and Pidogrel, although showed average percent releases of greater than 85%, their SEM and stand deviations were large showing widespread variations in unit contents. ANOVA gave a p>0.05, indicating a non-statistically significant difference between the means of active dissolved hence proving bioequivalence. CMA concluded that Ogrel may be used instead of the more expensive Plavix.

  13. Negative Ion Photoelectron Spectroscopy Reveals Thermodynamic Advantage of Organic Acids in Facilitating Formation of Bisulfate Ion Clusters: Atmospheric Implications

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Gao-Lei; Lin, Wei; Deng, Shihu; Zhang, Jian; Zheng, Weijun; Paesani, Francesco; Wang, Xue B.

    2013-03-07

    Recent lab and field measurements have indicated critical roles of organic acids in enhancing new atmospheric aerosol formation. Such findings have stimulated theoretical studies with the aim of understanding interaction of organic acids with common aerosol nucleation precursors like bisulfate (HSO4-). In this Letter, we report a combined negative ion photoelectron spectroscopic and theoretical investigation of molecular clusters formed by HSO4- with succinic acid (SUA, HO2C(CH2)2CO2H), HSO4-(SUA)n (n = 0-2), along with HSO4-(H2O)n and HSO4-(H2SO4)n. It is found that one SUA molecule can stabilize HSO4- by ca. 39 kcal/mol, triple the corresponding value that one water molecule is capable of (ca. 13 kcal/mol). Molecular dynamics simulations and quantum chemical calculations reveal the most plausible structures of these clusters and attribute the stability of these clusters due to formation of strong hydrogen bonds. This work provides direct experimental evidence showing significant thermodynamic advantage by involving organic acid molecules to promote formation and growth in bisulfate clusters and aerosols.

  14. Vibrational spectra and fragmentation pathways of size-selected, D2-tagged ammonium/methylammonium bisulfate clusters.

    Science.gov (United States)

    Johnson, Christopher J; Johnson, Mark A

    2013-12-19

    Particles consisting of ammonia and sulfuric acid are widely regarded as seeds for atmospheric aerosol nucleation, and incorporation of alkylamines has been suggested to substantially accelerate their growth. Despite significant efforts, little direct experimental evidence exists for the structures and chemical processes underlying multicomponent particle nucleation. Here we are concerned with the positively charged clusters of ammonia and sulfuric acid with compositions H(+)(NH3)m(H2SO4)n (2 ≤ m ≤ 5, 1 ≤ n ≤ 4), for which equilibrium geometry structures have been reported in recent computational searches. The computed harmonic vibrational spectra of such minimum energy structures can be directly compared with the experimental spectra of each cluster composition isolated in the laboratory using cryogenic ion chemistry methods. We present one-photon (i.e., linear) infrared action spectra of the isolated gas phase ions cryogenically cooled to 10 K, allowing us to resolve the characteristic vibrational signatures of these clusters. Because the available calculated spectra for different structural candidates have been obtained using different levels of theory, we reoptimized the previously reported structures with several common electronic structure methods and find excellent agreement can be achieved for the (m = 3, n = 2) cluster using CAM-B3LYP with only minor structural differences from the previously identified geometries. At the larger sizes, the experimental spectra strongly resemble that observed for 180 nm ammonium bisulfate particles. The characteristic ammonium- and bisulfate-localized bands are clearly evident at all sizes studied, indicating that the cluster structures are indeed ionic in nature. With the likely (3,2) structure in hand, we then explore the spectral and structural changes caused when methylamine is substituted for ammonia. This process is found to occur with minimal perturbation of the unsubstituted cluster. The thermal

  15. Structure of butanol and hexanol at aqueous, ammonium bisulfate, and sulfuric acid solution surfaces investigated by vibrational sum frequency generation spectroscopy.

    Science.gov (United States)

    Van Loon, Lisa L; Minor, Rena N; Allen, Heather C

    2007-08-09

    The organization of 1-butanol and 1-hexanol at the air-liquid interface of aqueous, aqueous ammonium bisulfate, and sulfuric acid solutions was investigated using vibrational broad bandwidth sum frequency generation spectroscopy. There is spectroscopic evidence supporting the formation of centrosymmetric structures at the surface of pure butanol and pure hexanol. At aqueous, ammonium bisulfate, and at most sulfuric acid solution surfaces, butanol molecules organize in all-trans conformations. This suggests that butanol self-aggregates. The spectrum for the 0.052 M butanol in 59.5 wt % sulfuric acid solution is different from the other butanol solution spectra, that is, the surface butanol molecules are observed to possess a significant number of gauche defects. Relative to surface butanol, surface hexanol chains are more disordered at the surface of their respective solutions. Statistically, an increase in the number of gauche defects is expected for hexanol relative to butanol, a six carbon chain vs a four carbon chain. Yet, self-aggregation of hexanol at its aqueous solution surfaces is not ruled out because the methylene spectral contribution is relatively small. The surface spectra for butanol and hexanol also show evidence for salting out from the ammonium bisulfate solutions.

  16. Ⅰ晶型硫酸氢氯吡格雷的合成%Synthesis of clopidogrel bisulfate of crystal form Ⅰ

    Institute of Scientific and Technical Information of China (English)

    储刚; 刘守志; 林辉

    2013-01-01

    Objective; To synthesize clopidogrel bisulfate of crystal form I . Methods; The optical purity of clopidogrel free alkali of S configuration was improved by salification reaction with L-camphorsulphonic acid; crystal form II was converted to crystal form I in a solvent system consisting of methanol and methyl tert-butyl e-ther. Results and Conclusion; Clopidogrel bisulfate of high purity is obtained and the process is industrially applicable.%目的:合成Ⅰ晶型硫酸氢氯吡格雷.方法:对S构型的氯吡格雷游离碱用左旋樟脑磺酸成盐来拆分进行光学纯度的提高;在甲醇-甲基叔丁基醚系统中将Ⅱ晶型转化得到Ⅰ晶型.结果与结论:获得高纯度硫酸氢氯吡格雷,工艺适合工业化生产.

  17. Comparative study of stability on clopidogrel bisulfate tablet polymorphs%两种晶型硫酸氢氯吡格雷片稳定性的比较

    Institute of Scientific and Technical Information of China (English)

    刘文乔; 于梦; 苗瑞娜; 丛鑫; 赵怀清

    2013-01-01

    目的 建立高效液相色谱法测定硫酸氢氯吡格雷片中的有关物质,并对2种晶型片剂的稳定性进行考察.方法 采用ULtron ES-OVM手性色谱柱(150 mm ×4.6 mm,5μm),流动相:0.01 mol·L-1磷酸二氢钾溶液-乙腈(体积比为75∶25),流速:1.0 mL· min-1,进样量:10μL,检测波长:220 nm,柱温:25℃.结果 在该色谱条件下,杂质A、杂质B的第一个异构体(杂质B1)、杂质C质量浓度分别在0.3 ~3.0、0.45 ~4.50、1.4~14.0 mg·L-1内与峰面积呈良好的线性关系,硫酸氢氯吡格雷与杂质B1之间的分离度大于2.5.稳定性试验表明,在高温条件下,两种晶型硫酸氢氯吡格雷片中杂质B、C含量明显增加,晶型Ⅰ杂质A略有增加;在高湿条件下2种晶型均易产生杂质A;在光照条件2种晶型的杂质均未明显增加.结论 高温是影响2种晶型硫酸氢氯吡格雷片稳定性的主要因素,2种晶型中Ⅱ型硫酸氢氯吡格雷片稳定性更佳.%Objective To develop an HPLC method for determining the related substances and stability of clopidogrel bisulfate tablet polymorphs.Methods The separation was performed on a ULtron ES-OVM column (150 mm ×4.6 mm,5 μm),the mobile phase was composed of 0.01 mol·L-1 potassium dihydrogen phosphate-acetonitrile (V∶ V =75∶25),the flow rate was set at 1.0 mL· min-1,the injection volume was 10 μL and the determination wavelength was set at 220 nm,the column temperature was 25 ℃.Results Using this method,the linearity ranges of impurity A,the first enantiomer of impurity B (impurity B1) and impurity C were 0.3-3.0,0.45-4.50 and 1.4-14.0 mg· L-1,respectively; and the resolution (R) between clopidogrel bisulfate and related compound B1 was greater than 2.5.In stability test,for two kinds of polymorphs of clopidogrel bisulfate tablets,the contents of impurities B and C increased obviously and that of impurity A increased slightly under high temperature; the content of impurity A increased under high humidity

  18. Toxicity of Ambient Particulate Matter IV: Acute toxicity study in pulmonary hypertensive rats after exposure to model compounds for the secondary aerosol fraction of PM10 - ammonium bisulfate, ferrosulfate and nitrate

    NARCIS (Netherlands)

    Cassee FR; Boere AJF; Fokkens PHB; Dormans JAMA; Bree L van; Rombout PJA; LEO; LPI

    1999-01-01

    This (4th) report on the toxicity of ambient particulate matter (PM) presents effects of the model compounds for PM in ambient air - ammonium bisulfate, ammonium ferrosulfate and ammonium nitrate - on healthy rats and rats with monocrotaline-induced pulmonary hypertension (PH). The objective was bas

  19. Uptake and diffusion of short chain alcohols into sulfuric acid and ammonium bisulfate solutions: considering the role of water in secondary organic aerosol formation.

    Science.gov (United States)

    van Loon, L. L.; Minor, R. N.; Allen, H. C.

    2006-12-01

    Secondary organic aerosol formation is of great interest since it may constitute an important fraction of tropospheric aerosols. These aerosols often contain a significant amount of sulfuric acid (40-80 wt%), which can be partially neutralized by ammonia, the most abundant basic species in the atmosphere. We have investigated the uptake of short-chain alcohols (n=1, 4, 6) by sulfuric acid and ammonium bisulfate solutions. First, methanol-sulfuric acid solutions were investigated using Raman spectroscopy. In 70+ wt% solutions of sulfuric acid, the formation of methyl sulfate was observed. In solutions of 70 wt% sulfuric acid or less no reaction was observed. While sulfuric acid is partially neutralized by ammonia, ammonium bisulfate is still quite acidic (pH 2). Studies have shown enhanced oxidation of gas-phase species in the presence of acidic particles such as NH4HSO4,1 suggesting a reaction between the particles and organic species. Solutions of ammonium bisulfate and methanol were investigated, but no methyl sulfate was detected. The surface enhancement of alcohols on sulfuric acid solutions was also investigated using sum frequency generation spectroscopy. From all these experiments we conclude that the formation of organosulfates, and therefore possible aerosol growth, is controlled by the amount of water present in the system. Second, Raman spectroscopy was used to determine the diffusion coefficients of methanol in sulfuric acid solutions. This method allows the diffusion of gas-phase methanol into aqueous solutions to be monitored simply using a Raman probe over the course of several hours. From the time data we are able to extract the diffusion coefficients. We have determined DAB = (1.7 ± 0.2) x 10^{-5} cm2/s for methanol into water and DAB = (2.5 ± 0.5) x 10^{-5} cm2/s for methanol into 96.6 wt% sulfuric acid at 293 K. 1. M. Jang, N. M. Czoschke, A. L. Northcross, Environ. Sci. Technol., 39, 164 (2005).

  20. Role of perfluorosulfonic ionomer as protective agent against strong adsorption of (bi)sulfate anions. Relevance in the determination of the area of Pt/C electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Rodriguez, S.; Rojas, S.; Pena, M.A.; Fierro, J.L.G. [Grupo de Quimica y Energia Sostenibles, Instituto de Catalisis y Petroleoquimica, CSIC C/Marie Curie 2, 28049 Madrid (Spain); Vellosillo, M.; Ocon, P. [Departamento de Quimica-Fisica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain)

    2010-10-15

    This work aims to shed light on the wide dispersion of the values of the area of Pt/C electrodes reported when evaluated by means of the thin-film electrode approach. The effect of the Perfluorosulfonic Ionomer (PFSI) content of the electrodes and the nature of the electrolyte are discussed. The results disclose that the area of the Pt electrodes evaluated by electrochemical techniques is related to the actual PFSI content on the electrode and to the nature of the electrolyte. Using HClO{sub 4} as electrolyte, electrode area values are independent of the PFSI content. On the contrary, if experiments are recorded in H{sub 2}SO{sub 4}, the electrode area value increases with the increasing PFSI content, irrespectively of the Pt loading. Such effect is ascribed to the interaction of the sulfonic groups from the PFSI with the surface of the Pt nanoparticles, avoiding the strong adsorption of the bisulfate anions. (author)

  1. A validated stability-indicating normal phase LC method for clopidogrel bisulfate and its impurities in bulk drug and pharmaceutical dosage form.

    Science.gov (United States)

    Durga Rao, Dantu; Kalyanaraman, L; Sait, Shakil S; Venkata Rao, P

    2010-05-01

    A novel stability-indicating normal phase liquid chromatographic (NP-LC) method was developed for the determination of purity of clopidogrel drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of clopidogrel along with the chiral impurities. This method can be also be used for the estimation of assay of clopidogrel in drug substance as well as in drug product. The method was developed using Chiralcel OJ-H (250mmx4.6mm, 5microm) column. n-Hexane, ethanol and diethyl amine in 95:5:0.05 (v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 240nm. Clopidogrel bisulfate was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.

  2. Near-Barrierless Ammonium Bisulfate Formation via a Loop-Structure Promoted Proton-Transfer Mechanism on the Surface of Water.

    Science.gov (United States)

    Li, Lei; Kumar, Manoj; Zhu, Chongqin; Zhong, Jie; Francisco, Joseph S; Zeng, Xiao Cheng

    2016-02-17

    In the atmosphere, a well-known and conventional pathway toward the formation of ammonium sulfate is through the neutralization of sulfuric acid with ammonia (NH3) in water droplets. Here, we present direct ab initio molecular dynamics simulation evidence of the formation of ammonium bisulfate (NH4HSO4) from the hydrated NH3 and SO3 molecules in a water trimer as well as on the surface of a water droplet. This reaction suggests a new mechanism for the formation of ammonium sulfate in the atmosphere, especially when the concentration of NH3 is high (e.g., ∼10 μg m(-3)) in the air. Contrary to the water monomer and dimer, the water trimer enables near-barrierless proton transfer via the formation of a unique loop structure around the reaction center. The formation of the loop structure promotes the splitting of a water molecule in the proton-transfer center, resulting in the generation a NH4(+)/HSO4(-) ion pair. The loop-structure promoted proton-transfer mechanism is expected to be ubiquitous on the surface of cloud droplets with adsorbed NH3 and SO3 molecules and, thus, may play an important role in the nucleation of aerosol particles (e.g., fine particles PM2.5) in water droplets.

  3. Synthesis of n-Butyl Salicylate Catalyzed by Sodium Bisulfate%硫酸氢钠催化合成水杨酸正丁酯

    Institute of Scientific and Technical Information of China (English)

    吴春燕

    2015-01-01

    Butyl salicylate was synthesized from salicylic acid and n-butanol catalyzed by sodium bisulfate.The effect of the molar ratio of n-butanol to salicylic acid,the reaction time,the amount of catalyst was discussed. Optimal conditions were obtained:the molar ratio of n-butanol to salicylic acid was 1.6:1, the reaction time was 4h and the mass ratio of catalyst to salicylic acid was 6%, the yield of butyl salicylate was 60.66%.%以水杨酸和正丁醇为原料,硫酸氢钠为催化剂,合成了水杨酸正丁酯。考察了正丁醇与水杨酸摩尔比、反应时间、催化剂用量对酯化收率的影响。通过实验得到最佳工艺条件为:正丁醇与水杨酸摩尔比为1.6∶1,反应时间为4h,催化剂用量为水杨酸用量的6%(质量分数),水杨酸正丁酯收率可达60.66%。

  4. HPLC法测定硫酸氢氯吡格雷片中氯吡格雷含量的不确定度评定%Evaluation of uncertainty for determination of clopidogrel in clopidogrel bisulfate tablets

    Institute of Scientific and Technical Information of China (English)

    朱莉

    2014-01-01

    Objective:To establish a method of uncertainty evaluation for the determination of clopidogrel in clopidogrel bisulfate tablets by HPLC.Methods:The calculation formula of uncertainty was deduced in the procedure of determining clopidogrel in tablets.Results:The combined uncertainty was 0.5%,the extended uncertainty was 1.0%,and the determined content was (101.0 ±1.0)%.Conclusion:This method is appropriate to be used in the uncertainty evaluation for the determination of clopidogrel in clopidogrel bisulfate tablets by HPLC.%目的:建立HPLC法测定硫酸氢氯吡格雷片中氯吡格雷含量不确定度的评定方法。方法:通过建立HPLC法测定含量的数学模型,分析影响不确定度的因素,并对各个不确定度分量进行评估。结果:硫酸氢氯吡格雷片中氯吡格雷含量测定的合成不确定度为0.5%;扩展不确定度为1.0%;测定结果为(101.0±1.0)%。结论:该法可用于HPLC法测定硫酸氢氯吡格雷片中氯吡格雷含量的不确定度评估。

  5. UPLC-MS determination the related compound of clopidogrel Bisulfate%硫酸氢氯吡格雷的有关物质UPLC-MS测定方法的研究

    Institute of Scientific and Technical Information of China (English)

    孙丽; 郑子栋; 李洁; 王豫辉; 王巨才

    2012-01-01

    Objective To establish an UPLC - MS method for determination of the related Compound of Clopidogrel Bi-sulfate. Methods The separation was performed on a Ultron ES - OVM column(15cm ×4mm,5μn) ,and the mobile phase consisted of 0.03mol · L-1 Ammonium acetate solution - Acetonitrile ( 78: 22 ) at the flow rale of 0.8 mL · min-1.Column temperature:30℃,Injection volume: 10μl. Results High temperature degradation products (Impurity A,Molecular formula:C15H14C1NO2S,Molecular weight:307. 8; ImpurityC, Molecular formula:C16H16C1NO2 S · H2SO4, Molecular weight :419. 90) and known impurities of lopidogrel Bisulfate can be effectively separated. Conclusions The method developed is stable and reliable, By comparison Chromatogram with foreign products, Domestic Clopidogrel Bisulfale has the fewer impurities and high quality.%目的 研究建立硫酸氢氯吡格雷有关物质的UPLC-MS测定方法,考察其国产原料药有关物质.方法 选用ULTRON ES-OVM 手性色谱柱(15cm×4mm,5μm),流动相:0.03 mol/L的醋酸氯溶液-乙腈(78:22),流速:0.8 mL/min,柱温:30℃,进样量:10μl.结果 硫酸氢氯吡格雷的高温降解产物(杂质A,分子式:C15H14C1NO2S,分子量:307.8;杂质C,分子式:C16H16CINO2S·H2SO4,分子量:419.90)及各已知杂质可有效分离.结论 该方法稳定可靠,经与国外产品图谱对比,国产硫酸氢氯吡格雷的杂质少,质量较高.

  6. 微波辐射硫酸氢钠催化合成对氨基苯甲酸苄酯%Synthesis of 4-aminobenzoic acid benzyl ester catalyzed by sodium bisulfate under microwave radiation

    Institute of Scientific and Technical Information of China (English)

    杨晓军; 李西安

    2011-01-01

    在微波辐射下,以一水合硫酸氢钠为催化剂,对氨基苯甲酸和苯甲醇为原料,合成对氨基苯甲酸苄酯.结果表明,当微波辐射功率为500W,0.05mol对氨基苯甲酸为基准,催化剂的用量为1.6 g,酸醇的摩尔比为1∶1.2,反应时间14 min时,醋化率达93.8%.%The 4-aminobcnzoic acid benzyl ester was synthesized under microwave radiacion from 4-aminobenzoic acid and benzyl alcohol using sodium bisulfate as catalyst. When the power of microwave radiation was 500 W, amount of catalyst was 1. 6 g, the molar ratio of acid to alcohol was 1∶ 1.2( using 0. 05 mol of 4-aminobenzoic acid ) and reaction time was 14 min, the yield reached 93. 8% .

  7. 二氧化硅负载硫酸氢钠催化合成乙酰水杨酸%Synthesis of acetyl salicylic acid with silica supported sodium bisulfate as catalyst

    Institute of Scientific and Technical Information of China (English)

    陈盛余; 蓝姣玉; 赵丹丹; 李丽; 韦唯; 肖彩玲; 张才莲

    2015-01-01

    The synthesis of acetyl salicylic acid with salicylic acid and acetic anhydride as reactants and sodium bisulfate as catalys supported by silica was studied.The factors influencing its catalytic performance were investigated and optimized , including reaction time, reaction temperature, the amount of catalyst.When the amount of salicylic acid was 7.0 g and the amount of acetic anhydride was 11.0 g,the optimum reaction conditions were as follows: the amount of catalyst was 0.6 g;the reaction time was 50 min , the reaction temperature was 80℃.The yield of acetyl salicylic acid was 80.1%.The catalyst could be recycled and used for 3 times.The process would improve the production of acetyl salicylic acid.%研究了以二氧化硅负载硫酸氢钠为催化剂,水杨酸和乙酸酐为原料合成乙酰水杨酸的工艺。考察了催化剂用量、反应时间、反应温度的影响。当固定水杨酸为7.0 g,乙酸酐为11.0 g时,乙酰水杨酸的优化合成条件为:催化剂用量0.6 g,反应时间为50 min,反应温度为80℃。在此条件下,乙酰水杨酸产率为80.1%。催化剂能够重复使用3次。该工艺将改善乙酰水杨酸的生产。

  8. 阿司匹林、硫酸氢氯吡格雷双联抗血小板聚集联合阿托伐他汀钙治疗进展性脑梗死疗效观察%Aspirin and Clopidogrel Bisulfate Dual Antiplatelet Aggregation Joint Atorvastatin Calcium Treatment of Progressive Cerebral Infarction Curative Effect Observation

    Institute of Scientific and Technical Information of China (English)

    刘金星; 霍莹; 葛汝丽

    2015-01-01

    ABSTRACT:Objective:Effects of aspirin, Clopidogrel bisulfate dual antiplatelet aggregation joint atorvastatin calcium in the treatment of progressive cerebral infarction clinical curative effect. Method 180 patients with progressive cerebral infarction were randomly divided into group A (control group), Group B (atorvastatin calcium), Group C (combination group), 60 cases in each group. A group was given conventional drug treatment;On the basis of conventional treatment group B, Simvastatin 20 mg every night instead of oral atorvastatin calcium 20 mg oral every night, Stay 2 weeks. In the hospital, Progress stops and 2 weeks after treatment respectively by the national institute of stroke score (NIHSS) scores to evaluate three groups of patients with nerve function defect degree, And observe the onset to the symptoms of peak time. Result Three groups of patients in the onset of symptoms to reach peak time and the treatment 2 weeks after the NIHSS score difference was statistically significant. conclusion aspirin、Clopidogrel bisulfate dual antiplatelet aggregation joint atorvastatin calcium treatment of progressive cerebral infarction curative effect signiifcantly, Safe and reliable, Worthy of clinical promotion.%目的:探讨阿司匹林、硫酸氢氯吡格雷双联抗血小板聚集联合阿托伐他汀钙治疗进展性脑梗死的临床疗效。方法将180例进展性脑梗死患者随机分为A组(对照组)、B组(阿托伐他汀钙组)、C组(联合用药组),每组60例。A组给予常规药物治疗;B组在接受常规治疗的基础上,将辛伐他汀20mg每晚口服改为阿托伐他汀钙片20mg每晚口服,连用2周;C组在B组基础上加用硫酸氢氯吡格雷75mg早上口服,连用2周。在入院时、进展停止时及治疗2周后分别用美国国立研究所脑卒中评分(NIHSS)评估三组患者神经功能缺损程度,并观察发病至症状达高峰的时间。结果3组患者在发病至症状

  9. Factorial study on influence of gas generating agent and diluent on drug release kinetics of clopidogrel bisulfate floating tablets

    Directory of Open Access Journals (Sweden)

    K R Koteswara Rao

    2013-01-01

    Full Text Available The purpose of present work was to formulate and characterize a floating drug delivery system for Clopidogrel bisulphate to improve bioavailability and to minimize the side-effects of the drug such as gastric bleeding and drug resistance development. Clopidogrel floating tablets were prepared by direct compression technique by the use of xanthan gum at different concentrations (20%, 25% and 30% w/w. Sodium bicarbonate (15% w/w and microcrystalline cellulose (MCC (30% w/w were used as gas generating agent and diluent respectively. The effects of sodium bicarbonate and MCC on the drug release kinetics and floating properties were investigated. A 2 2 factorial design was applied systematically to optimized formulation. The percentage amount of sodium bicarbonate (X 1 and percentage amount of MCC (X 2 were selected as independent variables. The drug release rate constant (K and time required for 85% drug dissolution (T85 was selected as dependent variables. Factorial design revealed that the percentage amount of sodium bicarbonate and MCC had insignificant effect on drug release kinetics (K, T85 within the chosen levels and a high level of sodium bicarbonate (X 1 and the low level of MCC (X 2 favor the preparation of clopidogrel floating tablets. All the Clopidogrel floating formulations followed first order kinetics, Higuchi drug release kinetics with diffusion as the dominant mechanism of drug release. As per Korsmeyer-Peppas equation, the release exponent "n" ranged 0.455-0.654 indicating that drug release from all the formulations was by non-fickian diffusion mechanism.

  10. Evaluation of feed grade sodium bisulfate impact on gastrointestinal tract microbiota ecology in broilers via a pyrosequencing platform

    Science.gov (United States)

    The gastrointestinal microbial community in broiler chicken consists of many different species of bacteria and the overall microbiota can be various from bird to bird. In order to control pathogenic bacteria in broiler and improve gut health, numerous potential dietary amendments such as prebiotics...

  11. Related Substances Determination of Clopidogrel Bisulfate by HPLC%HPLC法测定硫酸氢氯吡格雷中有关物质含量

    Institute of Scientific and Technical Information of China (English)

    郭海波; 郭旭光; 查岭

    2013-01-01

    建立HPLC法测定硫酸氢氯吡格雷有关物质的含量.采用ULTRON ES-OVM(150 mm ×4.6 mm,5μm)色谱柱,0.O1 mol·L-1磷酸二氢钾-乙腈(75:25)为流动相,流速1.0 mL·min-1,检测波长220 nm.硫酸氢氯吡格雷与各杂质分离良好,杂质A在0.204~8.16 μg·mL-1范围内,峰面积与浓度呈良好的线性关系(r=0.9990),平均回收率为98.73%,RSD为0.69%,最低检测限2.12 ng;杂质B在0.597 ~23.88 μg· mL-1范围内,峰面积与浓度呈良好的线性关系(r=0.9999),平均回收率为99.56%,RSD为0.92%,最低检测限2.83 ng;杂质C在1.004~ 40.16 μg·mL.1范围内,峰面积与浓度呈良好的线性关系(r=0.9998),平均回收率为100.01%,RSD为0.54%,最低检测限10.82ng.该方法操作简便、灵敏、准确度高,可用于硫酸氢氯吡格雷的质量控制.

  12. Determination of Clopidogrel Bisulfate Tablets by HPLC%HPLC法测定硫酸氢氯吡格雷片的含量

    Institute of Scientific and Technical Information of China (English)

    郑子栋

    2011-01-01

    目的 建立硫酸氢氯吡格雷片含量测定方法.方法 选用ULTRON ES-OVM手性色谱柱(15 cm×4 mm,5 μm),流动相:0.03 mol·L-1乙酸铵溶液-乙腈(78:22),流速:0.8 mL·min-1,检测波长:230 nm.结果 硫酸氢氯吡格雷线性范围40.8 ~142.9 μg·mL-1 (r=0.999 8),平均回收率97.5%.结论 本方法专属性强,可用于该制剂的含量测定.

  13. A Model for Voltammograms of the Under-Potential Deposition of Copper on Solid Gold (111) in the Presence of Bisulfate

    Science.gov (United States)

    1993-01-15

    H2 S0 4 wis recently proposed. In this model we assumed that the HS04 ions fornmed a V3 x lattice which produced a honeycomtb template for the...An improved effective field model in which the electrodeposition potential of the HS04 changes with the amltount of adsorbed copper is suggested...observable sharp spike in the voltammograni. 2. the HS04 ion retains its charge at the surface. In our previous work we assumed that the Vi3 x V3

  14. Development and Validation of an HPLC Method for Simultaneous Quantification of Clopidogrel Bisulfate, Its Carboxylic Acid Metabolite, and Atorvastatin in Human Plasma: Application to a Pharmacokinetic Study

    Directory of Open Access Journals (Sweden)

    Octavian Croitoru

    2015-01-01

    Full Text Available A simple, sensitive, and specific reversed phase liquid chromatographic method was developed and validated for simultaneous quantification of clopidogrel, its carboxylic acid metabolite, and atorvastatin in human serum. Plasma samples were deproteinized with acetonitrile and ibuprofen was chosen as internal standard. Chromatographic separation was performed on an BDS Hypersil C18 column (250 × 4.6 mm; 5 μm via gradient elution with mobile phase consisting of 10 mM phosphoric acid (sodium buffer solution (pH = 2.6 adjusted with 85% orthophosphoric acid : acetonitrile : methanol with flow rate of 1 mL·min−1. Detection was achieved with PDA detector at 220 nm. The method was validated in terms of linearity, sensitivity, precision, accuracy, limit of quantification, and stability tests. Calibration curves of the analytes were found to be linear in the range of 0.008–2 μg·mL−1 for clopidogrel, 0.01–4 μg·mL−1 for its carboxylic acid metabolite, and 0.005–2.5 μg·mL−1 for atorvastatin. The results of accuracy (as recovery with ibuprofen as internal standard were in the range of 96–98% for clopidogrel, 94–98% for its carboxylic acid metabolite, and 90–99% for atorvastatin, respectively.

  15. 硫酸氢钾催化合成尼泊金丁酯%Synthesis of Butyl Paraben Catalyzed by Potassium Bisulfate

    Institute of Scientific and Technical Information of China (English)

    陈丹云; 周慧; 何建英

    2006-01-01

    采用KHSO4为催化剂合成了尼泊金丁酯,考察了催化剂用量、正丁醇与对羟基苯甲酸摩尔比、反应时间、催化剂重复使用次数及带水剂等因素对收率的影响.结果表明:KHSO4具有催化活性高,易分离回收,重复使用性良好等优势.最佳反应条件为:正丁醇与对羟基苯甲酸摩尔比为3∶1,催化剂用量3 g,反应时间3h,收率92.9%.

  16. 硫酸氢钾催化合成己酸己酯%Synthesis of Hexyl Hexanoate Catalyzed by Potassium Bisulfate

    Institute of Scientific and Technical Information of China (English)

    陈丹云; 李宏

    2006-01-01

    目的 研究硫酸氢钾在合成己酸己酯工艺中的催化性能.方法 考察了硫酸氢钾用量、醇酸物质的摩尔比、反应时间、带水剂用量及催化剂重复使用次数等因素对收率的影响.结果 硫酸氢钾具有催化活性高,易分离回收,操作简单,后处理方便,重复使用性良好等优势.最佳反应条件下收率为99.4%.结论 硫酸氢钾是合成己酸己酯的良好催化剂.

  17. 硫酸氢钾催化合成乙酰水杨酸的研究%Study on the synthesis of acetyl salicylic acid with potassium bisulfate as catalyst

    Institute of Scientific and Technical Information of China (English)

    钟路平

    2006-01-01

    硫酸氢钾对水杨酸和醋酸酐合成乙酰水杨酸具有良好的催化作用.最佳的合成条件:水杨酸与醋酸酐的物质的量比为1∶2,硫酸氢钾用量为反应物总量的7%,反应时间为40min,反应温度为70℃,产率为76.4%.

  18. 硫酸氢氯吡格雷异构体的手性拆分及其限量检查%Chiral separation and limit test of clopidogrel bisulfate isomers

    Institute of Scientific and Technical Information of China (English)

    丁锐; 纪宏; 吕雯; 周长明; 李志刚; 张首国; 彭涛; 王林

    2012-01-01

    采用卵类黏蛋白手性固定相键合硅胶( Ultron ES-OVM)色谱柱(150mm×4.6mm,5μm),建立手性固定相HPLC直接拆分硫酸氢氯吡格雷对映异构体和位置异构体的方法,并通过对溶质计量置换保留模型、热力学参数、熵焓驱动过程及影响色谱行为的因素等内容进行研究,对手性拆分过程进行探讨.经优化,确定色谱条件为:流动相0.02 mol/L磷酸二氢钾-乙腈(80∶20),流速0.8mL/min,检测波长220 nm,柱温30℃.硫酸氢氯吡格雷的对映异构体和位置异构体之间的分离度均大于1.6;S-硫酸氢氯吡格雷、R-硫酸氢氯吡格雷及其各自位置异构体的定量限分别为0.115,0.102,0.118,0.106 mg/L,在0.33~20.68,0.63~40.20,0.32~20.20,0.31~19.28 mg/L浓度范围内线性关系良好;按外标法计算,加样回收率在98.2%~101.7%之间;RSD小于2.0%.经方法学验证,该方法可用于硫酸氢氯吡格雷异构体杂质含量测定.

  19. 硫酸氢季铵盐催化环氧化物和氮杂环丙烷的醇解反应%Alcoholysis of Epoxides and Aziridines Catalyzed by Quaternary Ammonium Bisulfate

    Institute of Scientific and Technical Information of China (English)

    张万轩; 叶康; 刘丽琴; 曹锰

    2009-01-01

    利用四丁基硫酸氢铵(TBAHS)和大孔树脂(D201型)支载的硫酸氢季铵盐(D201-HS04),分别催化环氧化合物或氮杂环丙烷与甲醇的开环反应,以高产率得到β-甲氧基醇或β-甲氧基胺,两种催化剂对该反应都很有效,但大孔树脂支载的硫酸氧季铵盐(D201-HSO4)易于制备,并可以重复使用.

  20. An Investigation on Decomposition of Wengfu Phosphorus Ore with Mixture Solution of Sulfuric Acid and Ammonium Bisulfate%硫酸和硫酸氢铵混合分解翁福磷矿

    Institute of Scientific and Technical Information of China (English)

    高春杰; 李春; 邱礼有; 梁斌

    2009-01-01

    对硫酸和硫酸氢铵混合分解贵州翁福磷矿进行了研究.结果表明,加料方式与速度、SO2-4/CaO和H2SO4/NH4HSO4比值以及初始硫酸根浓度等对磷矿的酸解有显著的影响.其优化工艺条件为:硫酸与磷矿并流加入,加料时间50min,SO2-4/CaO=1.3,H2SO4/NH4HSO4=4/4.8,反应温度70℃.在此条件下,磷矿的分解率约为94%.与纯硫酸分解磷矿相比,本方法可节约硫酸约50%.另外,本研究发现NH+4的引入可以使硫酸钙形成均匀的针状晶体,从而改善酸解浆料的过滤性能.

  1. Repair, Evaluation, Maintenance, and Rehabilitation Research Program. State-of-the-Art Procedures for Sealing Coastal Structures with Grouts and Concretes

    Science.gov (United States)

    1989-04-01

    sulfurous , boric, carbonic, and oxalic acid . Spe- cific salts include sodium bisulfate , sodium tetraborate, sodium bicarbonate, potassium-hydrogen oxalate...potassium bichromate, ferric chloride, sulfuric acid , aluminum sulfate (alum), aluminum chloride, ammonium persulfate, and copper sulfate. The bichromates... bisulfates , bicarbonates, sulfur dioxide, and sodium silico- fluoride. Sodium silicate also reacts with salts of some metals, such as 23 calcium

  2. Heterogenous uptake of gaseous N(sub 2)O(sub 5) by sulfate aerosols

    Science.gov (United States)

    Leu, M. -T.; Kane, S. M.; Caloz, F.

    2001-01-01

    The heterogeneous uptake of gaseous N sub 2 O sub 5 by ammonium sulfate, ammonium bisulfate, and sulfuric acid aerosols as a function of relative humididty has been investigated at room temperature and atmsopheric pressure.

  3. Drug: D00769 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D00769 Drug Clopidogrel sulfate (JAN); Clopidogrel bisulfate (USAN); Isocover (TN);...9 ATC code: B01AC04 CYP2C19 poor metabolizer status is associated with diminished response to Clopidogrel. P...affecting metabolism 33 Blood and body fluid agents 339 Miscellaneous 3399 Others D00769 Clopidogrel... sulfate (JAN); Clopidogrel bisulfate (USAN) Anatomical Therapeutic Chemical (ATC) classi...B01AC Platelet aggregation inhibitors excl. heparin B01AC04 Clopidogrel D00769 Clopidogrel

  4. Amine reactivity with charged sulfuric acid clusters

    OpenAIRE

    Bzdek, B. R.; D. P. Ridge; Johnston, M. V.

    2011-01-01

    The distribution of ionic species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neu...

  5. Amine reactivity with charged sulfuric acid clusters

    OpenAIRE

    Bzdek, B. R.; D. P. Ridge; Johnston, M. V.

    2011-01-01

    The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid n...

  6. Conversion of Guanidine Nitrate to Nitroguanidine with Recycle of Spent Acid

    Science.gov (United States)

    1975-10-01

    ammonium salt in concentrated sulfuric acid solutions is actually present as ammonium bisulfate and, therefore, the available free sulfuric ...of ammonium bisulfate . This plot more closely corresponds to handbook data for sulfuric acid -water but still exhibits a depression of the boiling...Sulfate Recycled Spent Acid Ammonium Sulfate Sulfuric Acid 20 ABSTRACT (Continue on revet»» elate If neceaeary and Identify by

  7. Forecasting Atmospheric Particulate Sulfur Concentrations Using National Weather Service Synoptic Charts

    Science.gov (United States)

    1990-08-01

    ammonium bisulfate (NH4HSO4 ), ammonium sulfate ((NH 4)2SO 4), or sulfuric acid aerosol (H2SO4 ) (Tanner 1981; Georgii 1982, p. 301...particulate sulfur is primarily NH4HSO4 ( ammonium bisulfate ), and (NH4)2SO 4 ( ammonium sulfate) (Warneck 1988, p. 317). The relatively long residence...time and transport distances of atmospheric sulfur aerosols may allow for sulfuric acid deposition far from the sulfur source region. The long

  8. A Mercury-Catalyzed, High-Yield System for the Oxidation of Methane to Methanol

    Science.gov (United States)

    Periana, Roy A.; Taube, Douglas J.; Evitt, Eric R.; Loffler, Daniel G.; Wentrcek, Paul R.; Voss, George; Masuda, Toshihiko

    1993-01-01

    A homogeneous system for the selective, catalytic oxidation of methane to methanol via methyl bisulfate is reported. The net reaction catalyzed by mercuric ions, Hg(II), is the oxidation of methane by concentrated sulfuric acid to produce methyl bisulfate, water, and sulfur dioxide. The reaction is efficient. At a methane conversion of 50 percent, 85 percent selectivity to methyl bisulfate (~43 percent yield; the major side product is carbon dioxide) was achieved at a molar productivity of 10-7 mole per cubic centimeter per second and Hg(II) turnover frequency of 10-3 per second. Separate hydrolysis of methyl bisulfate and reoxidation of the sulfur dioxide with air provides a potentially practical scheme for the oxidation of methane to methanol with molecular oxygen. The primary steps of the Hg(II)-catalyzed reaction were individually examined and the essential elements of the mechanism were identified. The Hg(II) ion reacts with methane by an electrophilic displacement mechanism to produce an observable species, CH_3HgOSO_3H, 1. Under the reaction conditions, 1 readily decomposes to CH_3OSO_3H and the reduced mercurous species, Hg_22+. The catalytic cycle is completed by the reoxidation of Hg_22+ with H_2SO_4 to regenerate Hg(II) and byproducts SO_2 and H_2O. Thallium(III), palladium(II), and the cations of platinum and gold also oxidize methane to methyl bisulfate in sulfuric acid.

  9. A new magnesium bisulfite pretreatment (MBSP) development for bio-ethanol production from corn stover.

    Science.gov (United States)

    Yu, Heng; Ren, Jiwei; Liu, Lei; Zheng, Zhaojuan; Zhu, Junjun; Yong, Qiang; Ouyang, Jia

    2016-01-01

    This study established a new more neutral magnesium bisulfate pretreatment (MBSP) using magnesium bisulfate as sulfonating agent for improving the enzymatic hydrolysis efficiency of corn stover. Using the MBSP with 5.21% magnesium bisulfate, 170°C and pH 5.2 for 60 min, about 90% of lignin and 80% of hemicellulose were removed from biomass and more than 90% cellulose conversion of substrate was achieved after 48 h hydrolysis. About 6.19 kg raw corn stover could produce 1 kg ethanol by Saccharomyces cerevisiae. Meanwhile, MBSP also could protect sugars from excessive degradation, prevent fermentation inhibition formation and directly convert the hemicelluloses into xylooligosaccharides as higher-value products. These results suggested that the MBSP method offers an alternative approach to the efficient conversion of nonwoody lignocellulosic biomass to ethanol and had broad space for development.

  10. Composition of Aerosols Over the Continential U.S.

    Science.gov (United States)

    1991-07-12

    term associated with sulfate. For ammonium sulfate D =4.5, for bisulfate D = 3.8, and D =1 for sulfuric acid . In order to estimate the organics via the... ammonium sulfate. Figure 16. The 3rd quarter aerosol constituents at each eastern location. The sulfate is assumed to be in the form of sulfuric acid , and...degree of neutralization by ammonium . The three common forms of particulate sulfate are ammonium sulfate ((NH4)2SO4), bisulfate (NH4 HSO4), and sulfuric

  11. Synthesis, structure and biological activity of 3,7-dinitrodibenzobromonium salt

    Institute of Scientific and Technical Information of China (English)

    侯自杰; 祝英; 王勤

    1996-01-01

    3,7-Dinitrodibenzobromonium bisulfate 3 was prepared directly by the reaction of4,4’ -dinitrobiphenyl with sodium bromide and potassium persulfate in the concentrated sulphuric acid. Metathetical reactions of 3 gave 3, T-dinitrodibenzobromonium chloride 4, bromide 5 and iodide 6, respectively. Crystal structure of 3a obtained by crystallization of 3 in formic acid showed that each molecule of 3a consists of two dibenzobromonium ions, two bisulfate anions and a formic acid. The dibenzobromonium ion is nearly coplanar. Compound 3 can dramatically increase mice’s immunofunction.

  12. Improved Monitoring Methods for Performance Assessment During Remediation of DNAPL Source Zones

    Science.gov (United States)

    2010-04-01

    contaminant partitioning behavior should be investigated in more depth. Contaminants with different chemical properties (i.e., PAHs ) should be considered...samples against biodegradation using sodium bisulfate, which is not considered a hazardous material during shipping, but this does not preserve

  13. Effect of on-farm litter acidification treatments on Campylobacter and Salmonella populations in comercial broiler houses in northeast Georgia.

    Science.gov (United States)

    Two commercially available litter treatments, aluminum sulfate and sodium bisulfate, were tested to determine their effect on Campylobacter and Salmonella levels associated with commercial broilers during a 6 week grow-out period. A total of 20 broiler houses at 10 different locations were studied;...

  14. Sulfuric acid-ammonium sulfate aerosol: optical detection in the St. Louis region.

    Science.gov (United States)

    Charlson, R J; Vanderpol, A H; Covert, D S; Waggnoner, A P; Ahlquist, N C

    1974-04-12

    Nephelometric sensing of the deliquescence of ammonium sulfate produced by the reaction of sulfuric acid or ammonium bisulfate aerosol with ammonia provides a means for detecting these substances in air. Field experiments show them to be the dominant substances in the submicrometer, light-scattering aerosol in the St. Louis region.

  15. An Analysis of Army Hazardous Waste Disposal Cost Data

    Science.gov (United States)

    1991-04-01

    Acid Cl 1331 Ammonium Acid Flouride (aimonium - - biflouride) 1332 Acetic lb 1333 Blattery Electrolyte ( sulfuric acid ) lb - . . . 1334 Chromic...1341 Sulfuric lb 1342 Sodium Bisulfite (sodium acid sulfite) lb 1343 Sodium Bisulfate (sodium acid sulfate) lb 1344 Hydrofluosilicic Acid lb 1345...battery category CLINs (0500 - 0599) with CLIN 1333 for battery electrolyte ( sulfuric acid ), CLIN 1309 battery electrolyte ( sulfuric acid

  16. Ambient Air Monitoring for Sulfur Compounds

    Science.gov (United States)

    Forrest, Joseph; Newman, Leonard

    1973-01-01

    A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

  17. Pulmonary effects of ultrafine and fine ammonium salts aerosols in healthy and monocrotaline-treated rats following short-term exposure

    NARCIS (Netherlands)

    Cassee, F.R.; Arts, J.H.E.; Fokkens, P.H.B.; Spoor, S.M.; Boere, A.J.F.; Bree, L. van; Dormans, J.A.M.A.

    2002-01-01

    In the present study the effects of a 3-day inhalation exposure to model compounds for ambient particulate matter were investigated: ammonium bisulfate, ammonium ferrosulfate, and ammonium nitrate, all components of the secondary aerosol fraction of ambient particulate matter (PM), and carbon black

  18. Formation and growth of molecular clusters containing sulfuric acid, water, ammonia, and dimethylamine.

    Science.gov (United States)

    DePalma, Joseph W; Doren, Douglas J; Johnston, Murray V

    2014-07-24

    The structures and thermochemistry of molecular clusters containing sulfuric acid, water, ammonia, and/or dimethylamine ((CH3)2NH or DMA) are explored using a combination of Monte Carlo configuration sampling, semiempirical calculations, and density functional theory (DFT) calculations. Clusters are of the general form [(BH(+))n(HSO4(-))n(H2O)y], where B = NH3 or DMA, 2 ≤ n ≤ 8, and 0 ≤ y ≤ 10. Cluster formulas are written based on the computed structures, which uniformly show proton transfer from each sulfuric acid molecule to a base molecule while the water molecules remain un-ionized. Cluster formation is energetically favorable, owing to strong electrostatic attraction among the ions. Water has a minor effect on the energetics of cluster formation, lowering the free energy of formation by ∼ 10% depending on the cluster size and number of water molecules. Cluster growth (addition of one base molecule and one sulfuric acid molecule to a pre-existing cluster) and base substitution (substituting DMA for ammonia) are also energetically favorable processes for both anhydrous and hydrated clusters. However, the effect of water is different for different bases. Hydrated ammonium bisulfate clusters have a more favorable free energy for growth (i.e., incrementing n with fixed y) than anhydrous clusters, while the reverse is observed for dimethylammonium bisulfate clusters, where the free energy for growth is more favorable for anhydrous clusters. The substitution of DMA for ammonia in bisulfate clusters is favorable but exhibits a complex water dependence. Base substitution in smaller bisulfate clusters is enhanced by the presence of water, while base substitution in larger bisulfate clusters is less favorable for hydrated clusters than that for anhydrous clusters. While DMA substitution can stabilize small clusters containing one or a few sulfuric acid molecules, the free energy advantage of forming amine clusters relative to ammonia clusters becomes less

  19. Comparative biological potency of acidic sulfate aerosols: implications for the interpretation of laboratory and field studies.

    Science.gov (United States)

    Schlesinger, R B; Chen, L C

    1994-04-01

    Biological responses to inhaled acid sulfates result from the deposition of hydrogen ion (H+) on airway surfaces. Thus, effects from sulfuric acid and ammonium bisulfate, the two major ambient species, have been assumed to be the same for a given H+ concentration within the exposure atmosphere, assuming similar respiratory tract deposition patterns. However, recent inhalation studies have indicated that sulfuric acid is disproportionately potent compared to ammonium bisulfate when the H+ content of the exposure atmosphere is considered, suggesting that some factors following inhalation affect the amount of H+ contacting airway surfaces. This study assessed a mechanism potentially underlying this phenomenon, namely, the extent of neutralization by respiratory tract ammonia. This was evaluated using a physical model system designed to mimic transit of these aerosols in the upper respiratory tract of the animal model used in this laboratory, the rabbit. The results suggest that for equal exposure quantities of H+, more acid would be deposited when sulfuric acid is inhaled than when ammonium bisulfate is inhaled. Furthermore, results from a series of in vitro exposures of tracheal epithelial cells to sulfuric acid and ammonium bisulfate aerosols indicated that the biological response is a function of the total mass (ionic) concentration of H+ deliverable to the cells or the total extractable H+ per particle. The results of this study have possible implications for ambient monitoring of particulate-associated strong acidity, suggesting that it may be necessary to specilate such measures into the relative amounts of H+ as sulfuric acid or ammonium bisulfate in order to most accurately relate atmospheric acid levels to observed health effects. In addition, since much of the ambient particulate-associated H+ exists as sulfuric acid/ammonium bisulfate mixtures rather than pure compounds, H(+)-associated health effects from controlled exposure studies of sulfuric acid may

  20. Sequential Deposition of Copper on Solid Gold (111): A Statistical Model

    Science.gov (United States)

    1993-01-15

    have to be accounted for. In the present communication we amplify a previously proposed model [21] to include the dynamics of the HS04 adsorption...bisulfate inter- action is both long ranged and repulsive. If we assume, as we have done in our previous work [21, 20], that the HS04 sits in a tripod...position, that is with its three oxygen atoms directly atop the Au atoms of the surface, then the adsorption of one HS04 necessarily excludes nearest

  1. Salification of main alkaloids in Macleaya cordata extract with sulfuric acid%博落回提取物(MCE)中主要生物碱与硫酸成盐研究

    Institute of Scientific and Technical Information of China (English)

    许泷; 陈湘滨; 曾建国; 杜宇; 谈满良

    2011-01-01

    目的:测定博落回提取物(MCE)中4种生物碱与硫酸成盐的计量关系及其含量,为建立MCE的质量标准提供实验依据。方法:用HPLC法测定其中4种主要生物碱的含量;BaSO4沉淀重量法测定SO42-含量;NaOH酸碱电位滴定法测定H2SO4和HSO4-的总量。结果:硫酸氢根含量约为18%,生物碱的硫酸氢盐含量〉80%,游离硫酸含量约为0.76%。结论:MCE中生物碱以硫酸氢盐形式存在,而且血根碱和白屈菜红碱(苯并菲啶类生物碱)为其主要有效成分。%Objective: To determine the metrical relationship and content of four alkaloids in Macleaya cordata extract salification with sulfuric acid,and provide experimental basis for the quality standard ofMacleaya cordata extract.Methods: The content of four kinds of alkaloids were determined by HPLC,and the content of sulfate was determined by barium sulfate sediment weighting method,and the total amout of sulfuric acid and bisulfate ion was determined by sodium hydrate acid base electric titration.Results: The content of bisulfate ion was about 18%,the bisulfate salt of alkaloid was above 80%,and the content of liberated sulfuric acid was 0.76%.Conclusion: The alkaloids in Macleaya cordata extract were existed in the form of bisulfate,and the main active components were sanguinarine and chelerythrine(benzophenanthridine).

  2. Long Range Spoil Disposal Study. Part III. Sub-Study 2. Nature, Source, and Cause of Shoal. Appendix A,

    Science.gov (United States)

    1973-12-01

    hexane soluble ganically bound nitrogen in the tri-negative state D-5 to ammonium bisulfate by digestion with HEAVY METAL ANALYSIS sulfuric acid to which...72%) sulfuric acid sediment was dried by mixing with magnesium for 3 hours and diluting the solution to 0.5 N sulfate monohydrate prior to...obtained from spraying solutions are then added to the sample which is sulfuric acid -ethanol mixture on the sample with further diluted with distilled

  3. Department of Defense Federal Hazard Communication Training Program, Trainer’s Guide

    Science.gov (United States)

    1988-04-01

    strong alka PnwPrful nv4i7aera lKawod"u Ogcormoosmon or By"oucts Sulfur Oxides, Toxic Fluorine Compounds, Carbon Monoxide, Ammonium bisulfate Mardous...East Depot Signal Shop Sulfuric Acid Best Chemical Corp. Signal Shop Tight-Bond Cement Jones Industrial Corp. Car Repair Shop Tight-Seal Jones...Information Tell trainees: Marilyn works as a supervisor in a plant that uses ammonium nitrate to make gun powder and blasting agents. List choices and ask

  4. Stratus Ocean Reference Station (20 deg S, 85 deg W), Mooring Recovery and Deployment Cruise, R/V Ron Brown Cruise 04-11, December 5 - December 24, 2004

    Science.gov (United States)

    2005-05-01

    sulfuric acid volatilizes within a range from 400C to 150 0C (measurements made during Stratus 2003 found it to be around 90’C) and ammonium bisulfate ...collected through the water column were used for salinity analysis, microbial activity experiment (anaerobic ammonium -oxidation rates), oxygen...aerosol has grown. This ratio of growth is dependent on the composition of the aerosol, i.e. sodium chloride has a growth factor of about 2.2 and ammonium

  5. Effects of Air Polution on Human Exercise Performance,

    Science.gov (United States)

    1988-02-01

    Interaction of various acids and salts. The most commonly studied aerosols are ammonium sulfate, ammonium bisulfate and amnium nitrate. These compounds are eye...FIELD IGROUP SUB-GROUP ozone, nitrogen dioxide, peroxyacetyl nitrate, aerosols, sulfur dioxide, carbon monoxide ’Itrength, performance. 19. ABSTRC...ozone, peroxyacetyl nitrate, aerosols, sulfur dioxide, and nitrogen * dioxide. Only carb,:n monoxide has been show to reduce 2xercise performance

  6. Fragmentation and Growth Energetics of Clusters Relevant to Atmospheric New Particle Formation

    Science.gov (United States)

    Bzdek, B. R.; DePalma, J. W.; Ridge, D. P.; Laskin, J.; Johnston, M. V.

    2013-12-01

    The exact mechanisms by which small clusters form and grow in the atmosphere are poorly understood, but this process may significantly impact cloud condensation nuclei number concentrations and global climate. Sulfuric acid is the key chemical component to new particle formation. However, basic species such as ammonia are also important. Few laboratory experiments address the kinetics or thermodynamics of acid and base incorporation into small clusters. This work utilizes a Fourier transform ion cyclotron resonance mass spectrometer equipped with surface-induced dissociation (FTICR-SID) to investigate time- and collision energy-resolved fragmentation of positively charged ammonium bisulfate clusters. The assumption underlying the experiment is that cluster growth can be considered the reverse of cluster fragmentation. Critical energies for fragmentation are obtained from Rice-Ramsperger-Kassel-Marcus/Quasi-Equilibrium Theory (RRKM/QET) modeling of the experimental data and are compared to quantum chemical calculations of the thermodynamics of cluster fragmentation. Fragmentation of ammonium bisulfate clusters occurs by two pathways: 1) a two-step pathway whereby the cluster sequentially loses ammonia followed by sulfuric acid and 2) a one-step pathway whereby the cluster loses an ammonium bisulfate molecule. Experimental critical energies for loss of an ammonia molecule and loss of an ammonium bisulfate molecule are higher than the thermodynamic values. If cluster growth is considered the reverse of cluster fragmentation, these results suggest that these clusters can grow by first adding sulfuric acid and then adding ammonia. Additionally, these results suggest the presence of an activation barrier to describe the incorporation of ammonia into small acidic clusters and therefore imply that kinetically (i.e. diffusion) limited growth should not be assumed. An important corollary is that models of atmospheric new particle formation should be revised to consider

  7. Fragmentation energetics of clusters relevant to atmospheric new particle formation.

    Science.gov (United States)

    Bzdek, Bryan R; DePalma, Joseph W; Ridge, Douglas P; Laskin, Julia; Johnston, Murray V

    2013-02-27

    The exact mechanisms by which small clusters form and grow in the atmosphere are poorly understood, but this process may significantly impact cloud condensation nuclei number concentrations and global climate. Sulfuric acid is the key chemical component to new particle formation (NPF), but basic species such as ammonia are also important. Few laboratory experiments address the kinetics or thermodynamics of acid and base incorporation into small clusters. This work utilizes a Fourier transform ion cyclotron resonance mass spectrometer equipped with surface-induced dissociation to investigate time- and collision-energy-resolved fragmentation of positively charged ammonium bisulfate clusters. Critical energies for dissociation are obtained from Rice-Ramsperger-Kassel-Marcus/quasi-equilibrium theory modeling of the experimental data and are compared to quantum chemical calculations of the thermodynamics of cluster dissociation. Fragmentation of ammonium bisulfate clusters occurs by two pathways: (1) a two-step pathway whereby the cluster sequentially loses ammonia followed by sulfuric acid and (2) a one-step pathway whereby the cluster loses an ammonium bisulfate molecule. Experimental critical energies for loss of an ammonia molecule and loss of an ammonium bisulfate molecule are higher than the thermodynamic values. If cluster growth is considered the reverse of cluster fragmentation, these results require the presence of an activation barrier to describe the incorporation of ammonia into small acidic clusters and suggest that kinetically (i.e., diffusion) limited growth should not be assumed. An important corollary is that models of atmospheric NPF should be revised to consider activation barriers to individual chemical steps along the growth pathway.

  8. The Toxicity of Photographic Chemicals.

    Science.gov (United States)

    1980-10-01

    Silver Nitrate Sodium Bisulfate (Sodium Acid Sulfate) Sulfuric Acid Succi nal dehyde The chemicals listed above are all extremely corrosive to the skin... Acid , Glacial Ammonia ( Ammonium Hydroxide, Ammonia Water, Household Ammonia)I Formaldehyde, 37-percent Solution (Formal in) Hydrochloric Acid Hydrogen...vapors, acid vapors such as from acetic acid baths, and breakdown products such as sulfur dioxide over fix and stop baths require local fume exhaust

  9. Stratus 9/VOCALS: Ninth Setting of the Stratus Ocean Reference Station & VOCALS Regional Experiment. Cruise RB-08-06, September 29-December 2, 2008. Leg 1: Charleston-Arica, September 29-November 3, 2008, Leg 2: Arica-Arica, November 9?December 2, 2008

    Science.gov (United States)

    2009-04-01

    reactions to sulfuric acid aerosol, which as cloud condensation nuclei can change the optical properties, coverage, and lifetime of clouds, and hence...a time resolution of 60 minutes. For an aerosol with chemical composition of ammonium bisulfate , a SS% of 0.15 corresponds to a critical diameter...has been postulated that once emitted to the atmosphere, this reduced sulfur compound derived from phytoplankton is oxidized through a chain of

  10. Fragmentation Energetics of Clusters Relevant to Atmospheric New Particle Formation

    Energy Technology Data Exchange (ETDEWEB)

    Bzdek, Bryan R.; Depalma, Joseph W.; Ridge, Douglas P.; Laskin, Julia; Johnston, Murray V.

    2013-02-27

    The exact mechanisms by which small clusters form and grow in the atmosphere are poorly understood, but this process may significantly impact cloud condensation nuclei number concentrations and global climate. Sulfuric acid is the key chemical component to new particle formation, but basic species such as ammonia are also important. However, few laboratory experiments address the kinetics or thermodynamics of acid and base incorporation into small clusters. This work utilizes a Fourier transform ion cyclotron resonance mass spectrometer equipped with surface-induced dissociation (FTICR-SID) to investigate time- and collision energy-resolved fragmentation of positively charged ammonium bisulfate clusters. Critical energies for dissociation are obtained from Rice-Ramsperger-Kassel-Marcus/Quasi-Equilibrium Theory (RRKM/QET) modeling of the experimental data and are compared to quantum chemical calculations of the thermodynamics of cluster dissociation. Fragmentation of ammonium bisulfate clusters occurs by two pathways: 1) a two-step pathway whereby the cluster sequentially loses ammonia followed by sulfuric acid and 2) a one-step pathway whereby the cluster loses an ammonium bisulfate molecule. Experimental critical energies for loss of an ammonia molecule and loss of an ammonium bisulfate molecule are higher than the thermodynamic values. If cluster growth is considered the reverse of cluster fragmentation, these results require the presence of an activation barrier to describe the incorporation of ammonia into small acidic clusters and suggest that kinetically (i.e. diffusion) limited growth should not be assumed. An important corollary is that models of atmospheric NPF should be revised to consider activation barriers to individual chemical steps along the growth pathway.

  11. Parameters Affecting Hydrogen Chloride Measurements

    Science.gov (United States)

    1993-06-01

    contain sea salt, which is hygroscopic because of the magnesium chloride present, or ammonium bisulfate , which mostly comes from sulfur pollution and is...boosters release hydrogen chloride as a combustion product, and hydrazines or nitric acid can be spilled from liquid fuel motors. Monitoring the...solubility constant, and the second is the acid ionization constant. From experimental work, the product of the two constants is well established (Reference

  12. Amine reactivity with charged sulfuric acid clusters

    Science.gov (United States)

    Bzdek, B. R.; Ridge, D. P.; Johnston, M. V.

    2011-08-01

    The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge), both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia is also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4)(H2SO4)x]- and [(NH4)x(HSO4)x+1(H2SO4)3]-. Dimethylamine substitution for ammonia in [(NH4) x(HSO4) x+1(H2SO4)3]- clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 to bisulfate is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4) (H2SO4) x]- clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (>m/z 400), whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2-3 orders of magnitude slower than incorporation of dimethylamine either by substitution or addition. Therefore, in locations where amine levels are within a few orders of magnitude of ammonia levels, amine chemistry may compete favorably with ammonia chemistry.

  13. The partitioning of Nitric Acid between the gas phase and condensed phase of aqueous sulfate aerosols.

    Science.gov (United States)

    Mentel, T. F.; Folkers, M.; Sebald, H.; Wahner, A.

    2001-12-01

    The heterogeneous hydrolysis of N2O_5 on aqueous aerosol surfaces is an important source of atmospheric HNO3. We generated HNO3 by heterogeneous hydrolysis of N2O_5 on aqueous ammonium and sodium sulfate aerosols and studied its partitioning between the gas phase and the aerosol phase. The experiments were performed in the large aerosol chamber at the FZ-Jülich at several relative humidities. Gas phase processes and the composition of the aerosols were monitored on-line simultaneously by FTIR spectroscopy and by Steam Jet Aerosol Collection/Ion Chromatography. The aerosol size distributions in the range of 20 nm to 5 μ m were measured by differential electromobility classification and by aerodynamic particle sizing. In the presence of aqueous bisulfate and sulfate aerosols a fast heterogeneous formation HNO3 is observed. (The reaction probability of N2O_5 is about 0.02.) In the case of the acidic bisulfate aerosols the major fraction of heterogeneously formed HNO3 resides in the gas phase. For neutral sulfate aerosols a significant fraction of HNO3 is taken up by the condensed phase of the aerosols. This leads to a distinctive growth of the aerosol population during the heterogeneous hydrolysis of N2O_5, which is observable in the number size distribution as well as in IR extinction measurements. The observed partitioning of HNO3 between gas phase and aqueous aerosol phase can be quantitatively understood by a Pitzer based thermodynamic model for salt solutions of high ionic strength. The model calculations and low resolution FTIR spectroscopy demonstrate that protonation of sulfate to bisulfate is the driving force for the uptake of HNO3 in neutral sulfate aerosols.

  14. SEPARATION OF THORIUM FROM URANIUM

    Science.gov (United States)

    Bane, R.W.

    1959-09-01

    A description is given for the separation of thorium from uranium by forming an aqueous acidic solution containing ionic species of thorium, uranyl uranium, and hydroxylamine, flowing the solution through a column containing the phenol-formaldehyde type cation exchange resin to selectively adsorb substantially all the thorium values and a portion of the uranium values, flowing a dilute solution of hydrochloric acid through the column to desorb the uranium values, and then flowing a dilute aqueous acidic solution containing an ion, such as bisulfate, which has a complexing effect upon thortum through the column to desorb substantially all of the thorium.

  15. Catalytic Mechanism and Efficiency of Methane Oxidation by Hg(II) in Sulfuric Acid and Comparison to Radical Initiated Conditions

    OpenAIRE

    Fuller, Jack T.; Butler, Steven; Devarajan, Deepa; Jacobs, Austin; Hashiguchi, Brian G.; Konnick, Michael M.; Goddard, William A.; Gonzales, Jason M.; Periana, Roy A.; Ess, Daniel H.

    2016-01-01

    Methane conversion to methyl bisulfate by Hg^(II)(SO_4) in sulfuric acid is an example of fast and selective alkane oxidation catalysis. Dichotomous mechanisms involving C–H activation and electron transfer have been proposed based on experiments. Radical oxidation pathways have also been proposed for some reaction conditions. Hg^(II) is also of significant interest because as a d^(10) transition metal it is similar to d^(10) main-group metals that also oxidize alkanes. Density-functional cal...

  16. Adsorption and Assembly of Ions and Organic Molecules at Electrochemical Interfaces: Nanoscale Aspects

    Science.gov (United States)

    Yoshimoto, Soichiro; Itaya, Kingo

    2013-06-01

    We describe the history of electrochemical scanning tunneling microscopy (STM) and advances made in this field during the past 20 years. In situ STM allows one to monitor various electrode processes, such as the underpotential deposition of copper and silver ions; the specific adsorption of iodine and sulfate/bisulfate ions; electrochemical dissolution processes of silicon and gold single-crystal surfaces in electrolyte solutions; and the molecular assembly of metalloporphyrins, metallophthalocyanines, and fullerenes, at atomic and/or molecular resolution. Furthermore, a laser confocal microscope, combined with a differential interference contrast microscope, enables investigation of the dynamics of electrochemical processes at atomic resolution.

  17. Amine reactivity with charged sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    B. R. Bzdek

    2011-08-01

    Full Text Available The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS. Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge, both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia is also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4(H2SO4x] and [(NH4x(HSO4x+1(H2SO43]. Dimethylamine substitution for ammonia in [(NH4 x(HSO4 x+1(H2SO43] clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 to bisulfate is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4 (H2SO4 x] clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (>m/z 400, whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2–3 orders of magnitude slower than incorporation of dimethylamine either by substitution or addition

  18. Concentration-dependent apparent partition coefficients of ionic liquids possessing ethyl- and bi-sulphate anions.

    Science.gov (United States)

    Jain, Preeti; Kumar, Anil

    2016-01-14

    This study deals with the concentration dependent apparent partition coefficients log P of the ethyl and bisulfate-based ionic liquids. It is observed that the bisulfate-based ionic liquids show different behaviour with respect to concentration as compared to ethyl sulphate-based ionic liquids. It is significant and useful analysis for the further implementation of alkyl sulfate based ionic liquids as solvents in extraction processes. The log P values of the ethyl sulphate-based ionic liquids were noted to vary linearly with the concentration of the ionic liquid, whereas a flip-flop trend with the concentration for the log P values of the bisulphate-based ionic liquids was observed due to the difference in hydrogen bond accepting basicity and possibility of aggregate formation of these anions. The π-π interactions between the imidazolium and pyridinium rings were seen to affect the log P values. The alkyl chain length of anions was also observed to influence the log P values. The hydrophobicity of ionic liquid changes with the alkyl chain in the anion in the order; [HSO4](-) < [EtSO4](-) < [BuSO4](-).

  19. Efeito da aplicação de bissulfato de sódio sobre cama de frangos na sobrevivência de Escherichia coli e coliformes Effect of sodium bisulfite application on the bed of broiler on survival of Escherichia coli and coliforms

    Directory of Open Access Journals (Sweden)

    P.M. Carvalho Neto

    2007-02-01

    Full Text Available Avaliou-se o efeito do bissulfato de sódio, aplicado sobre a cama de frangos, criados em diferentes densidades, na sobrevivência de Escherichia coli e coliformes, utilizando-se as densidades de 12, 16 e 20 aves/m², com a inoculação de uma cepa de E. coli. Houve maior desenvolvimento microbiano no 21º dia de criação, com tendência de redução a partir daí. A eficácia do bissulfato de sódio foi maior nos primeiros dias do experimento.The effect of sodium bisulfate has been evaluated on survival of Escherichia coli and coliforms, when applied on the broiler beds, adopting different densities. It has been adopted densities of 12, 16 and 20 birds/m², using inoculations of E. coli strains. The results have shown the highest microbial development on the 21st day of inoculation, with a trend of a microbial reduction afterwards. The sodium bisulfate was efficient during the first days of analyses, reducing its efficacy during the experiment.

  20. Airway responses to sulfate and sulfuric acid aerosols in asthmatics. An exposure-response relationship.

    Science.gov (United States)

    Utell, M J; Morrow, P E; Speers, D M; Darling, J; Hyde, R W

    1983-09-01

    Epidemiologic studies support an association between elevated levels of sulfates and increased symptoms in asthmatics. To determine if these pollutants produce airway responses, 17 asthmatics inhaled the following sulfates: sodium bisulfate, ammonium sulfate, ammonium bisulfate (NH4HSO4), or sulfuric acid (H2SO4) aerosols with an aerodynamic diameter of 0.80 micron at concentrations of 100 micrograms/m3, 450 micrograms/m3, and 1,000 micrograms/m3. A sodium chloride (NaCl) aerosol of similar characteristics, administered by double-blind randomization, served as a control. Subjects breathed these aerosols for a 16-minute period via a mouthpiece. Deposition studies showed 54 to 65% retention of the inhaled aerosols. At the 1,000 micrograms/m3 concentration, the Threshold Limit Value for occupational exposure, H2SO4 and NH4HSO4 inhalation produced significant reductions in specific airway conductance (SGaw) (p less than 0.05) and forced expiratory volume in one second (p less than 0.01) compared with NaCl or pre-exposure values. At the 450 micrograms/m3 concentration, only H2SO4 inhalation produced a significant reduction in SGaw (p less than 0.01). At 100 micrograms/m3, a level 3 to 5 times greater than peak urban levels, no significant change in airway function occurred after any sulfate exposure. These data indicate that asthmatics demonstrate bronchoconstriction after brief exposure to common acidic sulfate pollutants.

  1. Ice Formation by Sulfate and Sulfuric Acid Aerosol Particles under Upper-Tropospheric Conditions.

    Science.gov (United States)

    Chen, Yalei; Demott, Paul J.; Kreidenweis, Sonia M.; Rogers, David C.; Eli Sherman, D.

    2000-11-01

    Ice formation in ammoniated sulfate and sulfuric acid aerosol particles under upper-tropospheric conditions was studied using a continuous flow thermal diffusion chamber. This technique allowed for particle exposure to controlled temperatures and relative humidities for known residence times. The phase states of (NH4)2SO4 and NH4HSO4 particles were found to have important impacts on their ice formation capabilities. Dry (NH4)2SO4 particles nucleated ice only at high relative humidity (RH 94%) with respect to water at temperatures between 40° and 60°C. This result suggested either an impedance or finite time dependence to deliquescence and subsequent homogeneous freezing nucleation. Ammonium sulfate particles that entered the diffusion chamber in a liquid state froze homogeneously at relative humidities that were 10% lower than where ice nucleated on initially dry particles. Likewise, crystalline or partially crystallized (as letovicite) NH4HSO4 particles required higher relative humidities for ice nucleation than did initially liquid bisulfate particles. Liquid particles of size 0.2 m composed of either ammonium sulfate or bisulfate froze at lower relative humidity at upper-tropospheric temperatures than did 0.05-m sulfuric acid aerosol particles. Comparison of calculated homogeneous freezing point depressions suggest that size effects on freezing may be more important than the degree of ammoniation of the sulfate compound.

  2. Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions

    Science.gov (United States)

    Praplan, A. P.; Schobesberger, S.; Bianchi, F.; Rissanen, M. P.; Ehn, M.; Jokinen, T.; Junninen, H.; Adamov, A.; Amorim, A.; Dommen, J.; Duplissy, J.; Hakala, J.; Hansel, A.; Heinritzi, M.; Kangasluoma, J.; Kirkby, J.; Krapf, M.; Kürten, A.; Lehtipalo, K.; Riccobono, F.; Rondo, L.; Sarnela, N.; Simon, M.; Tomé, A.; Tröstl, J.; Winkler, P. M.; Williamson, C.; Ye, P.; Curtius, J.; Baltensperger, U.; Donahue, N. M.; Kulmala, M.; Worsnop, D. R.

    2015-04-01

    This study presents the difference between oxidised organic compounds formed by α-pinene oxidation under various conditions in the CLOUD environmental chamber: (1) pure ozonolysis (in the presence of hydrogen as hydroxyl radical (OH) scavenger) and (2) OH oxidation (initiated by nitrous acid (HONO) photolysis by ultraviolet light) in the absence of ozone. We discuss results from three Atmospheric Pressure interface Time-of-Flight (APi-TOF) mass spectrometers measuring simultaneously the composition of naturally charged as well as neutral species (via chemical ionisation with nitrate). Natural chemical ionisation takes place in the CLOUD chamber and organic oxidised compounds form clusters with nitrate, bisulfate, bisulfate/sulfuric acid clusters, ammonium, and dimethylaminium, or get protonated. The results from this study show that this process is selective for various oxidised organic compounds with low molar mass and ions, so that in order to obtain a comprehensive picture of the elemental composition of oxidation products and their clustering behaviour, several instruments must be used. We compare oxidation products containing 10 and 20 carbon atoms and show that highly oxidised organic compounds are formed in the early stages of the oxidation.

  3. Parameterization of the Optical Properties of Sulfate Aerosols.

    Science.gov (United States)

    Li, J.; Wong, J. G. D.; Dobbie, J. S.; Chýlek, P.

    2001-01-01

    Parameterizations of the shortwave optical properties of ammonium sulfate [(NH4)2SO4], ammonium bisulfate (NH4HSO4), and sulfuric acid (H2SO4) are provided as functions of relative humidity for high and low spectral resolution band models. The optical property parameterization is simple in form and in its dependence on relative humidity. The growth of the aerosol particles is based on equilibrium saturation theory, and the optical properties are computed from Mie theory. The optical properties necessary for the most commonly used radiative transfer methods are provided.Results show that when relative humidity effects are included in the backscatter fraction the radiative forcing is found to be a more sensitive function of near infrared wavelengths compared to visible wavelengths. For increasing relative humidity, sulfuric acid is found to have a larger effect on radiative forcing compared to the forcing by ammonium sulfate or ammonium bisulfate. Also, as relative humidity increases, forcing increases to higher values for smaller mode size distributions compared to forcing by larger mode distributions. These parameterizations will enable climate forcing studies to be performed with radiative transfer schemes that more accurately represent sulfate influences on the radiation balance.

  4. Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions

    Directory of Open Access Journals (Sweden)

    A. P. Praplan

    2015-04-01

    Full Text Available This study presents the difference between oxidised organic compounds formed by α-pinene oxidation under various conditions in the CLOUD environmental chamber: (1 pure ozonolysis (in the presence of hydrogen as hydroxyl radical (OH scavenger and (2 OH oxidation (initiated by nitrous acid (HONO photolysis by ultraviolet light in the absence of ozone. We discuss results from three Atmospheric Pressure interface Time-of-Flight (APi-TOF mass spectrometers measuring simultaneously the composition of naturally charged as well as neutral species (via chemical ionisation with nitrate. Natural chemical ionisation takes place in the CLOUD chamber and organic oxidised compounds form clusters with nitrate, bisulfate, bisulfate/sulfuric acid clusters, ammonium, and dimethylaminium, or get protonated. The results from this study show that this process is selective for various oxidised organic compounds with low molar mass and ions, so that in order to obtain a comprehensive picture of the elemental composition of oxidation products and their clustering behaviour, several instruments must be used. We compare oxidation products containing 10 and 20 carbon atoms and show that highly oxidised organic compounds are formed in the early stages of the oxidation.

  5. 合成水杨酸甲酯的实验条件探究%Experimental conditions investigation about synthesis of methylis salicylas

    Institute of Scientific and Technical Information of China (English)

    竹李帅; 熊双喜; 龙威

    2013-01-01

    甲醇和水杨酸合成水杨酸甲酯是药物化学合成的热点.在NaHHSO4·H2O作为主要催化剂的前提下,通过实验研究了催化剂、甲醇用量与反应时间的关系,着重分析了带水剂因素对合成水杨酸甲酯收率的影响.实验结果表明:甲醇∶水扬酸摩尔比为0.60∶0.10、NaHSO4·H2O质量为0.30g、H2SO4质量为0.80g、带水剂体积为4.00mL时,回流分水时间为3.0~3.5h为水杨酸酯甲酯的最佳实验条件,最高产率约为77.0%.%Methanol and salicylic acid is a hot drug chemical synthesis in high yield synthesis methylis salicylas.In this paper,it studies dosage of sodium bisulfate catalyst,methanol dosage and response time,with admixture of select catalytic synthesis of methyl salicylate and other factors on the yield effects under conditions of water combined with sodium bisulfate catalyst,methanol and salicylic acid by high-yield synthesis of methyl salicylate.Experimental results demonstrate that Ester yields was upto 77.0% for the best conditions,when methanol∶water acid mole ratio of 0.6∶0.1 and sodium bisulfate is 0.3g,sulfuric acid in water 0.80g,4mL returning water,tion time 3 to 3.5h.

  6. Role of the anion in the underpotential deposition of cadmium on a Rh(111) electrode: probed by voltammetry and in situ scanning tunneling microscopy.

    Science.gov (United States)

    Ou Yang, Liang-Yueh; Bensliman, Fahd; Shue, Chia-Haw; Yang, Yaw-Chia; Zang, Ze-Haw; Wang, Li; Yau, Shueh-Lin; Yoshimoto, Soichiro; Itaya, Kingo

    2005-08-11

    In situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV) were employed to examine the underpotential deposition (UPD) of cadmium on a rhodium(111) electrode in sulfuric and hydrochloric acids. The (bi)sulfate and chloride anions in the electrolytes played a main role in controlling the number and arrangement of Cd adatoms. Deposition of Cd along with hydrogen adsorption occurred near 0.1 V (vs reversible hydrogen electrode) in either 0.05 M H2SO4 or 0.1 M HCl containing 1 mM Cd(ClO4)2. These coupled processes resulted in an erroneous coverage of Cd adatoms. The process of Cd deposition shifted positively to 0.3 V and thus separated from that of hydrogen in 0.05 M H2SO4 containing 0.5 M Cd2+. The amount of charge (80 microC/cm2) for Cd deposition in 0.5 M Cd2+ implied a coverage of 0.17 for the Cd adatoms, which agreed with in situ STM results. Regardless of [Cd2+], in situ STM imaging revealed a highly ordered Rh(111)-(6 x 6)-6Cd + HSO4- or SO42- structure in sulfuric acid,. In hydrochloric acid, in situ STM discerned a (2 x 2)-Cd + Cl structure at potentials where Cd deposition commenced. STM atomic resolution showed roughly one-quarter of a monolayer of Cd adatoms were deposited, ca. 50% more than in sulfuric acid. Dynamic in situ STM imaging showed potential dependent, reversible transformations between the (6 x 6) Cd adlattices and (square root 3 x square root 7)-(bi)sulfate structure, and between (2 x 2) and (square root 7 x square root 7)R19.1 degrees -Cl structures. The fact that different Cd structures observed in H2SO4 and HCl entailed the involvement of anions in Cd deposition, i.e. (bi)sulfate and chloride anions were codeposited with Cd adatoms on Rh(111).

  7. Amine reactivity with charged sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    B. R. Bzdek

    2011-05-01

    Full Text Available The distribution of ionic species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS. Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge, both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia are also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4(H2SO4x] and [(NH4x(HSO4x+1(H2SO43]. Dimethylamine substitution for ammonia in [(NH4x(HSO4x+1(H2SO43] clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4(H2SO4x]clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (> m/z 400, whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2–3 orders of magnitude slower than incorporation of dimethylamine either by

  8. Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008

    Science.gov (United States)

    Hamacher-Barth, Evelyne; Leck, Caroline; Jansson, Kjell

    2016-05-01

    The representation of aerosol properties and processes in climate models is fraught with large uncertainties. Especially at high northern latitudes a strong underprediction of aerosol concentrations and nucleation events is observed and can only be constrained by in situ observations based on the analysis of individual aerosol particles. To further reduce the uncertainties surrounding aerosol properties and their potential role as cloud condensation nuclei this study provides observational data resolved over size on morphological and chemical properties of aerosol particles collected in the summer high Arctic, north of 80° N. Aerosol particles were imaged with scanning and transmission electron microscopy and further evaluated with digital image analysis. In total, 3909 aerosol particles were imaged and categorized according to morphological similarities into three gross morphological groups: single particles, gel particles, and halo particles. Single particles were observed between 15 and 800 nm in diameter and represent the dominating type of particles (82 %). The majority of particles appeared to be marine gels with a broad Aitken mode peaking at 70 nm and accompanied by a minor fraction of ammonium (bi)sulfate with a maximum at 170 nm in number concentration. Gel particles (11 % of all particles) were observed between 45 and 800 nm with a maximum at 154 nm in diameter. Imaging with transmission electron microscopy allowed further morphological discrimination of gel particles in "aggregate" particles, "aggregate with film" particles, and "mucus-like" particles. Halo particles were observed above 75 nm and appeared to be ammonium (bi)sulfate (59 % of halo particles), gel matter (19 %), or decomposed gel matter (22 %), which were internally mixed with sulfuric acid, methane sulfonic acid, or ammonium (bi)sulfate with a maximum at 161 nm in diameter. Elemental dispersive X-ray spectroscopy analysis of individual particles revealed a prevalence of the monovalent

  9. Research on various factors influencing the moisture absorption property of sodium polyacrylate

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties of moisture absorption, such as monomer concentration, dosage of initiator, and reaction temperature were systematically investigated. The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material, such as silica gel, and molecular sieve. The best reaction condition and formula are based on the orthogonal experiment design. The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g. The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis. The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency, followed by monomer concentration and reaction temperature, while other factors have less influence.

  10. 固体酸催化合成水杨酸甲酯进展%Progress of Catalytic Synthesis for Methyl Salicylate with Solid Acid

    Institute of Scientific and Technical Information of China (English)

    刘美艳; 俞善信

    2011-01-01

    Solid acid is a good catalyst that can be used as catalyst for the esterification instead of sulphuric acid. The synthesis of methyl salicylate catalyzed by p-toluene sulfonic acid, amino sulfonic acid,strongly acidic cationic exchanged resin,cupric bromide, sodium bisulfate monohydrate, solid super acid,heteropoly acid and molecular sieve etc. were reviewed.%固体酸是一种优良的催化剂,能够替代硫酸作为酯化催化剂.评述了对甲苯磺酸、氨基磺酸、强酸性阳离子交换树脂、溴化铜、一水硫酸氢钠、固体超强酸、杂多酸和分子筛等催化合成水杨酸甲酯的方法.

  11. Micro-Bubble Experiments at the Van de Graaff Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Z. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, K. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Youker, A. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakhtang [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, D. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, S. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, G. F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-02-01

    In order to test and verify the experimental designs at the linear accelerator (LINAC), several micro-scale bubble ("micro-bubble") experiments were conducted with the 3-MeV Van de Graaff (VDG) electron accelerator. The experimental setups included a square quartz tube, sodium bisulfate solution with different concentrations, cooling coils, gas chromatography (GC) system, raster magnets, and two high-resolution cameras that were controlled by a LabVIEW program. Different beam currents were applied in the VDG irradiation. Bubble generation (radiolysis), thermal expansion, thermal convection, and radiation damage were observed in the experiments. Photographs, videos, and gas formation (O2 + H2) data were collected. The micro-bubble experiments at VDG indicate that the design of the full-scale bubble experiments at the LINAC is reasonable.

  12. Identification of Non-Faradaic Processes by Measurement of the Electrochemical Peltier Heat during the Silver Underpotential Deposition on Au(111).

    Science.gov (United States)

    Frittmann, Stefan; Halka, Vadym; Schuster, Rolf

    2016-04-04

    We measured the heat which is reversibly exchanged during the course of an electrochemical surface reaction, i.e., the deposition/dissolution of the first two monolayers of Ag on a Au(111) surface in (bi)sulfate and perchlorate containing electrolytes. The reversibly exchanged heat corresponds to the Peltier heat of the reaction and is linearly related to its entropy change, including also non-Faradaic side processes. Hence, the measurement of the Peltier heat provides thermodynamic information on the electrochemical processes which is complementary to the current-potential relations usually obtained by conventional electrochemical methods. From the variation of the molar Peltier heat during the various stages of the deposition reaction we inferred that co-adsorption processes of anions and Ag do not play a prominent role, while we find strong indications for a charge neutral substitution reaction of adsorbed anions by hydroxide, which would not show up in cyclic voltammetry.

  13. Reactions at the Metal Vertex of a Monometal Metallocarborane Cluster. The Chemistry of (closo-3,3-(PPh3)2-3-(HSO4)-3,1,2-RhC2B9H11) and (closo-3-(PPh3)-3,3-(NO3)-3,1,2RhC2B9H11).

    Science.gov (United States)

    1982-03-09

    REACTIONS AT THE METAL VERTEX OF A MONOMETAL METALLOCARBORANE CLUSTER. THE CHEMISTRY OF [cjloso-3,3-(PPh 3)2 -3-( HS04 )-3,l ,2-RhC2 B9Hl1 AND [clIosof-3...rhodacarborane species, a bisulfate complex [closo-3,3-(PPh 3)2-3-( HS04 )-3,1,2-RhC2B9Hll](2) 2 and a bidentate nitrate [closo-3-(PPh3)-3,3-(NO3...equivalents ef (PPN)+( HS04 )- caused the appearance of a new doublet in the 31P NMR spectrum at +32.4 ppm (JRh-P=1 2 7 Hz) with a corresponding

  14. What is Eating Ozone? Thermal Reactions between SO2 and O3 and Implications for the Icy Satellites

    Science.gov (United States)

    Loeffler, Mark; Hudson, Reggie L.; Gerakines, Perry A.

    2016-10-01

    Here we present first results on a non-radiolytic, thermally-driven reaction sequence in solid H2O + SO2 + O3 mixtures at 50 – 130 K, which produces bisulfate (HSO4-). The results show that at the temperatures of the Jovian satellites, SO2 and O3 will efficiently react making co-detection of these species unlikely. Our results also give a viable explanation for why O3 has not been detected on Callisto and why the concentration of SO2 appears to be highest in its leading hemisphere. Furthermore our results also predict that the SO2 concentration on Ganymede will be lowest in the trailing hemisphere, where the concentration of O3 is the highest. This work is supported by NASA's Outer Planets Research program.

  15. Catalytic functionalization of methane and light alkanes in supercritical carbon dioxide.

    Science.gov (United States)

    Fuentes, M Ángeles; Olmos, Andrea; Muñoz, Bianca K; Jacob, Kane; González-Núñez, M Elena; Mello, Rossella; Asensio, Gregorio; Caballero, Ana; Etienne, Michel; Pérez, Pedro J

    2014-08-25

    The development of catalytic methods for the effective functionalization of methane yet remains a challenge. The best system known to date is the so-called Catalytica Process based on the use of platinum catalysts to convert methane into methyl bisulfate with a TOF rate of 10(-3) s. In this contribution, we report a series of silver complexes containing perfluorinated tris(indazolyl)borate ligands that catalyze the functionalization of methane into ethyl propionate upon reaction with ethyl diazoacetate (EDA) by using supercritical carbon dioxide (scCO2) as the reaction medium. The employment of this reaction medium has also allowed the functionalization of ethane, propane, butane, and isobutane.

  16. Assessment of analytical techniques for characterization of crystalline clopidogrel forms in patent applications

    Directory of Open Access Journals (Sweden)

    Luiz Marcelo Lira

    2014-04-01

    Full Text Available The aim of this study was to evaluate two important aspects of patent applications of crystalline forms of drugs: (i the physicochemical characterization of the crystalline forms; and (ii the procedure for preparing crystals of the blockbuster drug clopidogrel. To this end, searches were conducted using online patent databases. The results showed that: (i the majority of patent applications for clopidogrel crystalline forms failed to comply with proposed Brazilian Patent Office guidelines. This was primarily due to insufficient number of analytical techniques evaluating the crystalline phase. In addition, some patent applications lacked assessment of chemical/crystallography purity; (ii use of more than two analytical techniques is important; and (iii the crystallization procedure for clopidogrel bisulfate form II were irreproducible based on the procedure given in the patent application.

  17. A method for detecting the presence of organic fraction in nucleation mode sized particles

    Science.gov (United States)

    Vaattovaara, P.; Räsänen, M.; Kühn, T.; Joutsensaari, J.; Laaksonen, A.

    2005-12-01

    New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, dammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

  18. Laboratory and field studies of stratospheric aerosols: Phase changes under high supersaturation

    Science.gov (United States)

    Hallet, John

    1991-02-01

    It is well known that water in the form of isolated small droplets supercool as much as 40 C below their equilibrium melting point. Solutions similarly supercool (with respect to water) and supersaturate (with respect of the solute). Experiments are described in which bulk solutions typical of atmospheric aerosols (nitric acid, sulfuric acid, and hydrates; ammonium sulfate; ammonium bisulfate; sodium chloride) are supercooled and/or supersaturated and nucleated to initiate crystal growth. Supersaturation of 300 percent is readily attainable, with linear growth of crystals increasing roughly as (supercooling/supersaturation)sup 2. The implication of the experiments is that the situation of metastability in polar stratosphere clouds is very likely, with nucleation only occuring under a high degree of supercooling or supersaturation.

  19. Parameterization of ammonia and water content of atmospheric droplets with fixed number of sulfuric acid molecules

    Science.gov (United States)

    Napari, I.; Makkonen, R.; Kulmala, M.; Vehkamäki, H.

    2006-12-01

    We present a parameterization for numbers of water and ammonia molecules in an equilibrium droplet with fixed number of sulfuric acid molecules at known relative humidity, ammonia mixing ratio and temperature. The radius of the droplet is also parameterized. The parameterizations are based on macroscopic model of solution droplets and up-to-date thermodynamics. The binary parameterizations are valid for temperatures 190-330 K and relative humidities 1-99%. The ternary parameterization can be used at temperatures 240-300 K, relative humidities 5-95%, and ammonia mixing ratios 10 - 4 -100 ppt. In both cases the parameterizations are valid for droplets containing up to 10 11 sulfuric acid molecules. The droplet composition is always between the limits of pure ammonium bisulfate and pure ammonium sulfate.

  20. Controlled exposures of human volunteers to sulfate aerosols. Health effects and aerosol characterization.

    Science.gov (United States)

    Avol, E L; Jones, M P; Bailey, R M; Chang, N M; Kleinman, M T; Linn, W S; Bell, K A; Hackney, J D

    1979-08-01

    Our laboratory has undertaken the study of possible acute adverse health effects of sulfate aerosols through controlled exposures of volunteer human subjects. Both healthy and asthmatic adult men were exposed for 2-hour periods (with intermittent exercise) to ammonium sulfate, ammonium bisulfate, and sulfuric acid of particle size distributions and concentrations intended to simulate "worst case" exposures during Los Angeles smog episodes. Lung function tests were performed by the subjects on entering and before exiting from a carefully controlled environmental chamber. Subject symptoms were evluated in a standardized manner. Aerosol concentrations and size distributions were determined by an on-line computer/aerometric monitoring system; gravimetric and chemical analyses were performed on impactor and total filter samples after test exposures. We found little or no evidence of adverse health effects from 2-hour multiple-day exposures to any of the compounds at "worst case" ambient concentrations.

  1. 新型氨法脱硫系统在硫酸行业尾气处理中的应用%Application of Desulphurization System by New Ammonia Method in Tail Gas Treatment for Sulfuric Acid Industry

    Institute of Scientific and Technical Information of China (English)

    卢红波; 田文慧; 张才华; 高晔

    2014-01-01

    Author has introduced the process flow for desulphurization system of new ammonia method;has briefly described its process principle and process feature;has presented the main control indexes of this desulphurization process.Result indicates that the desulphurization system by new ammonia method has advantages of high efficiency,small pressure drop of system and high oxidation rate of ammonium bisulfate etc..%介绍了新型氨法脱硫系统的工艺流程;简述了其工艺原理和工艺特点;提出了该脱硫工艺的主要控制指标。结果表明,该新型氨法脱硫系统具有效率高、系统阻力降小,亚硫酸铵氧化率高等优点。

  2. The Pacific Marine aerosol: Evidence for natural acid sulfates

    Science.gov (United States)

    Clarke, Antony D.; Ahlquist, Norman C.; Covert, David S.

    1987-04-01

    Optical, chemical, and physical measurements of marine boundary layer aerosol were made during two oceanographic cruises in the central Pacific in the fall of 1983 and spring of 1984. Both cruises revealed a ubiquitous accumulation mode atmospheric aerosol that showed marked increases in the region of equatorial upwelling, 4°N to 15°S, between Hawaii and Tahiti. Changes in the aerosol size distribution in response to thermal conditioning revealed properties consistent with those of sulfuric acid and/or ammonium sulfate/bisulfate depending upon the sampling location. Changes in the apparent acidity of the accumulation mode varied in conjunction with physical and chemical properties of the region sampled, while the number concentration suggests that it is the dominant and possibly limiting aerosol for cloud condensation nuclei in the remote central Pacific.

  3. Fragmentation and growth energetics of clusters relevant to new particle formation

    Science.gov (United States)

    Bzdek, Bryan R.; DePalma, Joseph W.; Ridge, Douglas P.; Laskin, Julia; Johnston, Murray V.

    2013-05-01

    The chemical mechanisms governing atmospheric new particle formation are not fully resolved, although this process may significantly impact cloud condensation nuclei levels. Whereas sulfuric acid is the key component, bases are also important in promoting nucleation and growth. This work utilizes a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) equipped with surface-induced dissociation (SID) to investigate time-and collision energy-resolved fragmentation of positively charged ammonium bisulfate clusters. Critical energies for dissociation are obtained from Rice-Ramsperger-Kassel-Marcus/Quasi-Equilibrium Theory (RRKM/QET) modeling of the experimental data and are compared to thermodynamic values. If cluster growth is considered the reverse of cluster dissociation, the results suggest that an activation barrier exists to the incorporation of ammonia into acidic clusters and that diffusion-limited cluster growth should not be assumed.

  4. Size dependence of surface thermodynamic properties of nanoparticles and its determination method by reaction rate constant

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wenjiao; Xue, Yongqiang, E-mail: xyqlw@126.com; Cui, Zixiang

    2016-08-15

    Surface thermodynamic properties are the fundamental properties of nanomaterials, and these properties depend on the size of nanoparticles. In this paper, relations of molar surface thermodynamic properties and surface heat capacity at constant pressure of nanoparticles with particle size were derived theoretically, and the method of obtaining the surface thermodynamic properties by reaction rate constant was put forward. The reaction of nano-MgO with sodium bisulfate solution was taken as a research system. The influence regularities of the particle size on the surface thermodynamic properties were discussed theoretically and experimentally, which show that the experimental regularities are in accordance with the corresponding theoretical relations. With the decreasing of nanoparticle size, the molar surface thermodynamic properties increase, while the surface heat capacity decreases (the absolute value increases). In addition, the surface thermodynamic properties are linearly related to the reciprocal of nanoparticle diameter, respectively.

  5. DNA methylation dynamics in the rat EGF gene promoter after partial hepatectomy

    Directory of Open Access Journals (Sweden)

    Deming Li

    2014-06-01

    Full Text Available Epidermal growth factor (EGF, a multifunctional growth factor, is a regulator in a wide variety of physiological processes. EGF plays an important role in the regulation of liver regeneration. This study was aimed at investigating the methylation level of EGF gene throughout liver regeneration. DNA of liver tissue from control rats and partial hepatectomy (PH rats at 10 time points was extracted and a 354 bp fragment including 10 CpG sites from the transcription start was amplified after DNA was modified by sodium bisulfate. The result of sequencing suggested that methylation ratio of four CpG sites was found to be significantly changed when PH group was compared to control group, in particular two of them were extremely striking. mRNA expression of EGF was down-regulated in total during liver regeneration. We think that the rat EGF promoter region is regulated by variation in DNA methylation during liver regeneration.

  6. PREPARATION AND PROPERTIES OF WHEAT GLUTEN/RICE PROTEIN COMPOSITES PLASTICIZED WITH GLYCEROL

    Institute of Scientific and Technical Information of China (English)

    Yan-yan Yang; Kai-zhou Zhang; Yi-hu Song; Qiang Zheng

    2011-01-01

    Environment friendly thermosetting composites were prepared by blending wheat gluten (WG) and rice protein (RP) at different weight ratios with glycerol as plasticizer followed by compression molding the mixture at 120C to crosslink the proteins. Reducing agent of sodium bisulfate and sodium sulfite and crosslinking agent formaldehyde were used to adjust the properties of the composites. Morphology, moisture absorption and tensile properties were evaluated. The results showed that formaldehyde could increase tensile strength of the composites without significant influence on Young's modulus and elongation at break. On the other hand, reducing agents could improve tensile strength and extensibility simultaneously, which was much marked at WG/RP ratios from 7/3 to 3/7.

  7. Synthesis and Characterization of Cellulose Acetate from TCF Oil Palm Empty Fruit Bunch Pulp

    Directory of Open Access Journals (Sweden)

    Fauzi Muhammad Djuned

    2014-06-01

    Full Text Available Cellulose acetate (CA was successfully synthesized by the acetylation of TCF cellulose pulp from oil palm empty fruit bunches (OPEFB at room temperature, using acetic anhydride as the acetylating agent and acetic acid as the solvent in the presence of sulfuric acid/sodium bisulfate as catalysts. Degree of substitution (DS was controlled by the variables of acetylation time and acetic anhydride to cellulose ratio, under the heterogeneous state. The product (CA obtained was characterized through Fourier transform infrared spectroscopy (FTIR, nuclear magnetic resonance spectroscopy (NMR, differential scanning calorimetry (DSC, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The results indicate that the CA obtained has characteristics similar to commercial CA, and DS is significantly dependent on acetylation time and the acetic anhydride-to-cellulose ratio.

  8. 水杨酸乙酯的绿色催化合成%Eco-friendly synthesis of ethyl salicylate

    Institute of Scientific and Technical Information of China (English)

    李启东; 袁旭宏; 叶余原; 黄海明; 陈红; 尤玉静; 熊双喜

    2014-01-01

    在NaHSO4·H2O复合催化剂的条件下,由乙醇和水杨酸为原料合成了较高收率水杨酸乙酯。该文研究了NaHSO4·H2O复合催化剂用量、乙醇使用量和反应时间,带水剂的选择等因素对催化合成水杨酸乙酯收率的影响。实验结果证明,当乙醇∶水扬酸摩尔比为5.5∶1和NaHSO4·H2O为1.8g,H2SO4在0.9g、带水剂6mL时,回流分水240~300min,酯收率达92.07%,为最佳反应条件。%Higher yield ethyl salicylate was synthesized by alcohol and salicylic acid with sodium bisulfate as catalyst. The effects of dosage of composite catalyst, alcohol dosage, reaction time and selection of water-carrying agent on the yield were studied. The results showed that ester yields were up to 93.07% when conditions were fol-lowing:the mole ratio of alcohol:salicylic acid was 5.5∶1, sodium bisulfate was 1.8g, sulfuric acid was 0.9g, water-carrying agent was 6mL and refluxing 240~300min.

  9. Laboratory scale studies on removal of chromium from industrial wastes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Chromium being one of the major toxic pollutants is discharged from electroplating and chrome tanning processes and is also found in the effluents of dyes, paint pigments, manufacturing units etc. Chromium exists in aqueous systems in both trivalent (Cr 3+) and hexavalent (Cr 6+) forms. The hexavalent form is carcinogenic and toxic to aquatic life, whereas Cr3+ is however comparatively less toxic. This study was undertaken to investigate the total chromium removal from industrial effluents by chemical means in order to achieve the Pakistan NEQS level of 1 mg/L by the methods of reduction and precipitation. The study was conducted in four phases.In phase I, the optimum pH and cost effective reducing agent among the four popular commercial chemicals was selected. As a result, pH of 2 was found to be most suitable and sodium meta bisulfate was found to be the most cost effective reducing agent respectively. Phase II showed that lower dose of sodium meta bisulfate was sufficient to obtain 100 % efficiency in reducing Cr6+ to Cr3+, and it was noted that reaction time had no significance in the whole process. A design curve for reduction process was established which can act as a tool for treatment of industrial effluents.Phase III studies indicated the best pH was 8.5 for precipitation of Cr 3+ to chromium hydroxide by using lime. An efficiency of 100 % was achievable and a settling time of 30 minutes produced clear effluent. Finally in Phase IV actual waste samples from chrome tanning and electroplating industries, when precipitated at pH of 12 gave 100 % efficiency at a settling time of 30 minutes and confirmed that chemical means of reduction and precipitation is a feasible and viable solution for treating chromium wastes from industries.

  10. Heterogeneous reactions of epoxides in acidic media.

    Science.gov (United States)

    Lal, Vinita; Khalizov, Alexei F; Lin, Yun; Galvan, Maria D; Connell, Brian T; Zhang, Renyi

    2012-06-21

    Epoxides have recently been identified as important intermediates in the gas phase oxidation of hydrocarbons, and their hydrolysis products have been observed in ambient aerosols. To evaluate the role of epoxides in the formation of secondary organic aerosols (SOA), the kinetics and mechanism of heterogeneous reactions of two model epoxides, isoprene oxide and α-pinene oxide, with sulfuric acid, ammonium bisulfate, and ammonium sulfate have been investigated using complementary experimental techniques. Kinetic experiments using a fast flow reactor coupled to an ion drift-chemical ionization mass spectrometer (ID-CIMS) show a fast irreversible loss of the epoxides with the uptake coefficients (γ) of (1.7 ± 0.1) × 10(-2) and (4.6 ± 0.3) × 10(-2) for isoprene oxide and α-pinene oxide, respectively, for 90 wt % H(2)SO(4) and at room temperature. Experiments using attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) reveal that diols are the major products in ammonium bisulfate and dilute H(2)SO(4) (65 wt %), acetals are formed from isoprene oxide, whereas organosulfates are produced from α-pinene oxide. The reaction of the epoxides with ammonium sulfate is slow and no products are observed. The epoxide reactions using bulk samples and Nuclear Magnetic Resonance (NMR) spectroscopy reveal the presence of diols as the major products for isoprene oxide, accompanied by aldehyde formation. For α-pinene oxide, organosulfate formation is observed with a yield increasing with the acidity. Large yields of organosulfates in all NMR experiments with α-pinene oxide are attributed to the kinetic isotope effect (KIE) from the use of deuterated sulfuric acid and water. Our results suggest that acid-catalyzed hydrolysis of epoxides results in the formation of a wide range of products, and some of the products have low volatility and contribute to SOA growth under ambient conditions prevailing in the urban atmosphere.

  11. Hydrogen peroxide maintains the heterogeneous reaction of sulfur dioxide on mineral dust proxy particles

    Science.gov (United States)

    Huang, Liubin; Zhao, Yue; Li, Huan; Chen, Zhongming

    2016-09-01

    The heterogeneous oxidation of sulfur dioxide (SO2) on α-Al2O3 particles was investigated using a flow reactor coupled with a transmission-Fourier transform infrared (T-FTIR) spectrometer at different relative humidities (RH) in the absence or presence of hydrogen peroxide (H2O2), with an emphasis on the saturation coverage of SO2 and the timescale on which the reaction reaches saturation. It is found that the saturation coverage of SO2 in the absence of H2O2 increases with rising RH due to the hydrolysis of SO2 by surface adsorbed water. However, the reaction ultimately reaches saturation since the produced sulfite/bisulfite cannot be further converted to sulfate/bisulfate in the absence of oxidants. In addition, the presence of H2O2 can significantly increase the saturation coverage of SO2 by efficiently oxidizing sulfite/bisulfite to sulfate/bisulfate. Under humid conditions, adsorbed water facilitates the hydrolysis of SO2 and mitigates the increase of surface acidity, which can inhibit the hydrolysis of SO2. Hence, in the presence of H2O2, the saturation coverage of SO2 as well as the time of reaction reaching saturation increases with rising RH and the surface is not saturated on the timescale of the experiments (40 h) at 60% RH. Furthermore, the increase of saturation coverage of SO2 in the presence of H2O2 was observed on chemically inactive SiO2 particles, indicating that the hydrolysis of SO2 and subsequent oxidation by H2O2 likely occurs on other types of particles. Our findings are of importance for understanding the role of water vapor and trace gases (e.g., H2O2) in the heterogeneous reaction of SO2 in the atmosphere.

  12. Theoretical study on the reactivity of sulfate species with hydrocarbons

    Science.gov (United States)

    Ma, Q.; Ellis, G.S.; Amrani, A.; Zhang, T.; Tang, Y.

    2008-01-01

    The abiotic, thermochemically controlled reduction of sulfate to hydrogen sulfide coupled with the oxidation of hydrocarbons, is termed thermochemical sulfate reduction (TSR), and is an important alteration process that affects petroleum accumulations in nature. Although TSR is commonly observed in high-temperature carbonate reservoirs, it has proven difficult to simulate in the laboratory under conditions resembling nature. The present study was designed to evaluate the relative reactivities of various sulfate species in order to provide greater insight into the mechanism of TSR and potentially to fill the gap between laboratory experimental data and geological observations. Accordingly, quantum mechanics density functional theory (DFT) was used to determine the activation energy required to reach a potential transition state for various aqueous systems involving simple hydrocarbons and different sulfate species. The entire reaction process that results in the reduction of sulfate to sulfide is far too complex to be modeled entirely; therefore, we examined what is believed to be the rate limiting step, namely, the reduction of sulfate S(VI) to sulfite S(IV). The results of the study show that water-solvated sulfate anions SO42 - are very stable due to their symmetrical molecular structure and spherical electronic distributions. Consequently, in the absence of catalysis, the reactivity of SO42 - is expected to be extremely low. However, both the protonation of sulfate to form bisulfate anions (HSO4-) and the formation of metal-sulfate contact ion-pairs could effectively destabilize the sulfate molecular structure, thereby making it more reactive. Previous reports of experimental simulations of TSR generally have involved the use of acidic solutions that contain elevated concentrations of HSO4- relative to SO42 -. However, in formation waters typically encountered in petroleum reservoirs, the concentration of HSO4- is likely to be significantly lower than the levels

  13. Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    S. T. Martin

    2004-01-01

    Full Text Available The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US and once for lower side (LS of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m2 (g SO4-2-1, which compare to US values of 0.030 and 13.9 m2 (g SO4-2-1. Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (FL and FU, respectively, in W m-2 are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of FL=-0.750, FU=-0.930, and DFU,L=24% for full sky calculations without clouds and FL=-0.485, FU=-0.605, and DFU,L=25% when clouds are included. Regionally, DFU,L=48% over the USA, 55% over Europe

  14. Study on refinement technology of high acid valued squid oil%高酸值鱿鱼油的精制工艺分析

    Institute of Scientific and Technical Information of China (English)

    杨小克; 李晓琳; 步营; 胡增淼; 王鹏

    2012-01-01

    To the fact that fish oil from squid processing wastes was of high acid value,which restrict its application,firstly,using sodium bisulfate to catalyze the reaction of ethyl esterification,then deacidification,decolorization,deodorization was studied to refine squid oil.The results showed that the optimum esterification molar ratio of methanol to oil was 20∶1,the amount of sodium bisulfate was 8%,reaction time was 5h,reaction temperature was 80℃,the conversion rate of esterification approaches to 90%.The refined fish oil was low acid valued,yellowish and clarified,with very light fishlike smell,the physical and chemical indexes accord with the first refined fish oil demand for SC/T 3502-2000 standard.The total content of PUFA was 38.34% in the defined fish oil,the content of EPA and DHA was 11.49% and 22.14%,respectively.%针对鱿鱼加工废弃物中提取的鱼油酸值高,使其应用受限这一现状,采取先酯化以降低其酸值,后脱酸、脱色、脱臭的方法对其进行精制。研究结果表明,以硫酸氢钠为催化剂酯化过程中各因素的最适条件为:醇酸物质的量比20∶1,催化剂用量8%(W/W),反应时间5h,反应温度80℃,该条件下酯化率可达90%左右。精制后鱼油酸值显著下降,澄清透明呈淡黄色,略带鱼腥味,各项理化指标均达到鱼油的SC/T3502-2000标准的精制鱼油一级要求。应用气相色谱分析精制鱼油的脂肪酸组成,其多不饱和脂肪酸(PUFA)的含量达38.34%,其中C20∶5(EPA)和C22∶6(DHA)的含量分别为11.49%和22.14%。

  15. Clinical significance of N-terminal pro-brain natriuretic peptide

    Institute of Scientific and Technical Information of China (English)

    张向阳; 朱继红

    2004-01-01

    @@ Traditionally, it was believed that the natriuretic peptide family (NPs) was composed of four natural peptides, i.e., atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP) and urodilatin. All of them have the same 17-amino acid ring connected by bisulfate bond, which is essential for their biological activity.1 There are C-terminal and N-terminal tails on the ring. Each peptide encoded by an independent gene has its own tissue specificity and regulation mechanism. It is now suggested that beside the four traditional peptides, their precursors and the peptide fragments released by the activation or hydrolysis of the precursors, such as precursor of ANP and N-terminal proANP (NTANP), precursor of BNP and N-terminal proBNP (NTBNP) are also NPs. Furthermore, an artificially synthesized NP, vasonatrin peptide, is also a new member of NP family. In fish like eel, another peptide named ventricular natriuretic peptide was found. We now have a review on the clinical significance of NTBNP.

  16. Research on various factors influencing the moisture absorption property of sodium polyacrylate

    Institute of Scientific and Technical Information of China (English)

    ZHANG ChunXiao; ZHANG WanXi; PAN ZhenYuan; ZHANG XiYao; LIU Jian; YUE ChongWang

    2009-01-01

    Sodium polyacrylate was synthesized with acrylic acid as the monomer,and sodium bisulfate and ammonium persulfate as the initiator,by means of aqueous solution polymerization.The factors influencing the properties of moisture absorption,such as monomer concentration,dosage of initiator,and reaction temperature were systematically investigated.The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material,such as silica gel,and molecular sieve.The best reaction condition and formula are based on the orthogonal experiment design.The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g.The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis.The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency,followed by monomer concentration and reaction temperature,while other factors have less influence.

  17. Synthesis of [{sup 123}I]iodine labelled imidazo[1,2-b] pyridazines as potential probes for the study of peripheral benzodiazepine receptors using SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Katsifis, A.; Mattner, F.; Dikic, B. [Radiopharmaceuticals Div. ANSTO, Menai, NSW (Australia); Barlin, G. [Div. of Neurosciences, John Curtin School of Medical Research, Australian National Univ., Canberra (Australia)

    2004-07-01

    The pyridazines 3-acetamidomethyl-6-chloro-2-(4'-iodophenyl)imidazo[1,2-b]pyridazine 1 (IC{sub 50} = 1.6 nM) and 3-benzamidomethyl-6-iodo-2-(4'-t-butylphenyl)imidazo[1,2-b] pyridazine 2 (IC{sub 50} = 4.2 nM), are high affinity and selective ligands for the peripheral benzodiazepine receptors (PBR) compared to the central benzodiazepine counterparts. The [{sup 123}I]1 and [{sup 123}I]2 labelled analogues of these compounds were subsequently synthesised for the potential study of the PBR in vivo using SPECT. Radioiodination of [{sup 123}I]1 was achieved by iododestannylation of the corresponding tributyl tin precursor with Na[{sup 123}I] in the presence of peracetic acid or chloramine-T and the product isolated by C-18 RP HPLC. Radioiodination of [{sup 123}I]2 was achieved by copper assisted bromine [{sup 123}I]iodine exchange of the corresponding bromo precursor in the presence of acetic acid and sodium bisulfate as reducing agent at 200 C. Purification of the crude products were achieved by semi-preparative C-18 RP HPLC to give the products in radiochemical yields > 90%. The products were obtained in > 97% chemical and radiochemical purity and with specific activities > 180 GBq/{mu}mol. (orig.)

  18. Determination of residues of acetaminophen, caffeine, and drotaverine hydrochloride on swabs collected from pharmaceutical manufacturing equipment using HPLC in support of cleaning validation.

    Science.gov (United States)

    Hassouna, Mohamed E M; Issa, Yousry M; Zayed, Ashraf G

    2014-01-01

    An HPLC method was developed for the simultaneous determination of residues of acetaminophen (paracetamol, PA), caffeine (CA), and drotaverine HCl (DH) on swabs collected from pharmaceutical manufacturing equipment surfaces. The challenge in cleaning validation is to develop analytical methods that are sensitive enough to detect traces of the active compounds remaining on the surface of pharmaceutical manufacturing equipment after cleaning. Chromatography was performed in the isocratic mode on a Hypersil C18 BDS column using the mobile phase 0.02 M tetrabutylammonium bisulfate-methanol (100 + 45, v/v) at 50°C with UV detection at 210 nm. The method was tested for specificity, linearity, LOD, LOQ, accuracy, and precision for determination of traces of the above-mentioned drugs. The time required for a single analysis was 12 min. The response was linear in the ranges of 6.900-52.100, 1.040-7.800, and 0.694-5.210 μg/mL for PA, CA, and DH, respectively.

  19. Embolization of a giant pediatric, posttraumatic, skull base internal carotid artery aneurysm with a liquid embolic agent.

    Science.gov (United States)

    Reig, Adam S; Simon, Scott; Mericle, Robert A

    2009-11-01

    Many treatments for posttraumatic, skull base aneurysms have been described. Eight months after an all-terrain-vehicle accident, this 12-year-old girl presented with right-side Horner syndrome caused by a 33 x 19-mm internal carotid artery aneurysm at the C-1 level. We chose to treat the aneurysm with a new liquid embolic agent for wide-necked, side-wall aneurysms (Onyx HD 500). We felt this treatment would result in less morbidity than surgery and was less likely to occlude the parent artery than placement of a covered stent, especially in a smaller artery in a pediatric patient. Liquid embolic agents also appear to be associated with a lower chance of recanalization and lower cost compared with stent-assisted coil embolization. After the patient was treated with loading doses of aspirin, clopidogrel bisulfate, and heparin, 99% of the aneurysm was embolized with 9 cc of the liquid embolic agent. There were no complications, and the patient remained neurologically stable. Follow-up angiography revealed durable aneurysm occlusion after 1 year. The cost of Onyx was less than the cost of coils required for coil embolization of similarly sized intracranial aneurysms at our institution. Liquid embolic agents can provide a safe, efficacious, and cost-effective approach to treatment of select giant, posttraumatic, skull base aneurysms in pediatric patients.

  20. Study on Synthesis of Methyl Salicylate%水杨酸甲酯的合成工艺研究

    Institute of Scientific and Technical Information of China (English)

    朱铭; 袁旭宏; 叶余原; 黄海明; 陈红; 尤玉静; 熊双喜

    2014-01-01

    通过水杨酸和甲醇为原料,分别在浓硫酸和硫酸氢钾催化作用下合成了水杨酸甲酯。考察了酸醇摩尔比、反应时间及催化剂用量对酯收率的影响。结果表明,使用硫酸氢钾做催化剂,n(水杨酸):n(甲醇)摩尔比=1:5,反应5 h,所获得的水杨酸甲酯的收率为最好,平均收率可以到达70%。%Using salicylic acid and methanol as raw materials, methyl salicylate was respectively synthesized in concentrated sulfuric acid or potassium hydrogen sulfate. Effect of mole ratio of acid to alcohol, reaction time and catalyst dosage on yield of the ester was investigated. The results show that ,using potassium bisulfate as catalyst, n (salicylic acid): n (methanol) = 1:5, reaction time 5 h, the highest yield of methyl salicylate can be obtained, average yield can reach to 70%.

  1. WBSA: Web Service for Bisulfite Sequencing Data Analysis

    Science.gov (United States)

    Wang, Yanqing; Wang, Jianfeng; Yu, Caixia; Chen, Xu; Zhu, Junwei; Yan, Jiangwei; Zhao, Wenming; Li, Rujiao

    2014-01-01

    Whole-Genome Bisulfite Sequencing (WGBS) and genome-wide Reduced Representation Bisulfite Sequencing (RRBS) are widely used to study DNA methylation. However, data analysis is complicated, lengthy, and hampered by a lack of seamless analytical pipelines. To address these issues, we developed a convenient, stable, and efficient web service called Web Service for Bisulfite Sequencing Data Analysis (WBSA) to analyze bisulfate sequencing data. WBSA focuses on not only CpG methylation, which is the most common biochemical modification in eukaryotic DNA, but also non-CG methylation, which have been observed in plants, iPS cells, oocytes, neurons and stem cells of human. WBSA comprises three main modules as follows: WGBS data analysis, RRBS data analysis, and differentially methylated region (DMR) identification. The WGBS and RRBS modules execute read mapping, methylation site identification, annotation, and advanced analysis, whereas the DMR module identifies actual DMRs and annotates their correlations to genes. WBSA can be accessed and used without charge either online or local version. WBSA also includes the executables of the Portable Batch System (PBS) and standalone versions that can be downloaded from the website together with the installation instructions. WBSA is available at no charge for academic users at http://wbsa.big.ac.cn. PMID:24497972

  2. Effect of Organic Coatings, Humidity and Aerosol Acidity on Multiphase Chemistry of Isoprene Epoxydiols.

    Science.gov (United States)

    Riva, Matthieu; Bell, David M; Hansen, Anne-Maria Kaldal; Drozd, Greg T; Zhang, Zhenfa; Gold, Avram; Imre, Dan; Surratt, Jason D; Glasius, Marianne; Zelenyuk, Alla

    2016-06-07

    Multiphase chemistry of isomeric isoprene epoxydiols (IEPOX) has been shown to be the dominant source of isoprene-derived secondary organic aerosol (SOA). Recent studies have reported particles composed of ammonium bisulfate (ABS) mixed with model organics exhibit slower rates of IEPOX uptake. In the present study, we investigate the effect of atmospherically relevant organic coatings of α-pinene (AP) SOA on the reactive uptake of trans-β-IEPOX onto ABS particles under different conditions and coating thicknesses. Single particle mass spectrometry was used to characterize in real-time particle size, shape, density, and quantitative composition before and after reaction with IEPOX. We find that IEPOX uptake by pure sulfate particles is a volume-controlled process, which results in particles with uniform concentration of IEPOX-derived SOA across a wide range of sizes. Aerosol acidity was shown to enhance IEPOX-derived SOA formation, consistent with recent studies. The presence of water has a weaker impact on IEPOX-derived SOA yield, but significantly enhanced formation of 2-methyltetrols, consistent with offline filter analysis. In contrast, IEPOX uptake by ABS particles coated with AP-derived SOA is lower compared to that of pure ABS particles, strongly dependent on particle composition, and therefore on particle size.

  3. Monoamine oxidase A gene DNA hypomethylation - a risk factor for panic disorder?

    Science.gov (United States)

    Domschke, Katharina; Tidow, Nicola; Kuithan, Henriette; Schwarte, Kathrin; Klauke, Benedikt; Ambrée, Oliver; Reif, Andreas; Schmidt, Hartmut; Arolt, Volker; Kersting, Anette; Zwanzger, Peter; Deckert, Jürgen

    2012-10-01

    The monoamine oxidase A (MAOA) gene has been suggested as a prime candidate in the pathogenesis of panic disorder. In the present study, DNA methylation patterns in the MAOA regulatory and exon 1/intron 1 region were investigated for association with panic disorder with particular attention to possible effects of gender and environmental factors. Sixty-five patients with panic disorder (44 females, 21 males) and 65 healthy controls were analysed for DNA methylation status at 42 MAOA CpG sites via direct sequencing of sodium bisulfate treated DNA extracted from blood cells. The occurrence of recent positive and negative life events was ascertained. Male subjects showed no or only very minor methylation with some evidence for relative hypomethylation at one CpG site in intron 1 in patients compared to controls. Female patients exhibited significantly lower methylation than healthy controls at 10 MAOA CpG sites in the promoter as well as in exon/intron 1, with significance surviving correction for multiple testing at four CpG sites (p≤0.001). Furthermore, in female subjects the occurrence of negative life events was associated with relatively decreased methylation, while positive life events were associated with increased methylation. The present pilot data suggest a potential role of MAOA gene hypomethylation in the pathogenesis of panic disorder particularly in female patients, possibly mediating a detrimental influence of negative life events. Future studies are warranted to replicate the present finding in independent samples, preferably in a longitudinal design.

  4. Gas Phase Conversion of Carbon Tetrachloride to Alkyl Chlorides Catalyzed by Supported Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    SUN Aijun; ZHANG Jinlong; LI Chunxi; MENG Hong

    2009-01-01

    An efficient way of converting carbon tetrachloride(CTC)to alkyl chlorides is reported,which uses the catalysts of ionic liquids supported on granular active carbon.The catalytic performance was evaluated in a temperature range of 120-200℃ and atmospheric pressure for different ionic liquids,namely 1-butyl-3-methylimidazolium chloride,1-octyl-3-methylimidazolium chloride,hydrochloric salts of N-methylimidazole(MIm),pyridine and triethylamine,as well as bisulfate and dihydric phosphate of N-methylimidazole.On this basis,the reaction mechanism was proposed,and the influences of the reaction temperature and the attributes of ionic liquids were discussed.The overall reaction was assumed to be comprised of two steps,the hydrolysis of CTC and reaction of HCI with alcohols under acidic catalyst.The results indicate that the conversion of CTC increased monotonically with temperature and even approached 100% at 200 ℃,while the maximum selectivity to alkyl chlorides was obtained around 160 ℃.This reaction might be potentially applicable to the resource utilization of superfluous byproduct of CTC in the chloromethane industry.

  5. Organic solvent-free reversed-phase ion-pairing liquid chromatography coupled to atomic fluorescence spectrometry for organoarsenic species determination in several matrices.

    Science.gov (United States)

    Monasterio, Romina P; Londonio, Juan A; Farias, Silvia S; Smichowski, Patricia; Wuilloud, Rodolfo G

    2011-04-27

    A novel method has been developed to determine As-containing animal feed additives including roxarsone (ROX), p-arsanilic acid (p-ASA) and nitarsone (NIT), as well as other organic As species (dimethylarsonic acid (DMAA) and monomethylarsonic acid (MMAA)) by ion-pairing high-performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry (IP-HPLC-HG-AFS). A simple isocratic reversed-phase (RP) HPLC method with a mobile phase containing citric acid and sodium hexanesulfonate (pH 2.0) was developed using a C(18) column. The use of an organic solvent free mobile phase turns this methodology into an environmentally friendly alternative. Several ion pair forming agents, such as sodium hexanesulfonate, tetrabutylammonium bisulfate and perfluoroheptanoic acid, were studied. The limits of detection for As species were calculated in standard solution and resulted to be 0.2, 0.5, 0.6, 1.6, and 1.6 μg As L(-1) for MMAA, DMAA, p-ASA, ROX and NIT, respectively. This method exhibited convenient operation, high sensitivity and good repeatability. It was applied to As speciation in different samples including arugula, dog food, dog urine and chicken liver.

  6. Theoretical study of the hydration of atmospheric nucleation precursors with acetic acid.

    Science.gov (United States)

    Zhu, Yu-Peng; Liu, Yi-Rong; Huang, Teng; Jiang, Shuai; Xu, Kang-Ming; Wen, Hui; Zhang, Wei-Jun; Huang, Wei

    2014-09-11

    While atmosphere is known to contain a significant fraction of organic substance and the effect of acetic acid to stabilize hydrated sulfuric acids is found to be close that of ammonia, the details about the hydration of (CH3COOH)(H2SO4)2 are poorly understood, especially for the larger clusters with more water molecules. We have investigated structural characteristics and thermodynamics of the hydrates using density functional theory (DFT) at PW91PW91/6-311++G(3df,3pd) level. The phenomena of the structural evolution may exist during the early stage of the clusters formation, and we tentatively proposed a calculation path for the Gibbs free energies of the clusters formation via the structural evolution. The results in this study supply a picture of the first deprotonation of sulfuric acids for a system consisting of two sulfuric acid molecules, an acetic acid molecule, and up to three waters at 0 and 298.15 K, respectively. We also replace one of the sulfuric acids with a bisulfate anion in (CH3COOH)(H2SO4)2 to explore the difference of acid dissociation between two series of clusters and interaction of performance in clusters growth between ion-mediated nucleation and organics-enhanced nucleation.

  7. Effect of Organic Coatings, Humidity and Aerosol Acidity on Multiphase Chemistry of Isoprene Epoxydiols

    Energy Technology Data Exchange (ETDEWEB)

    Riva, Matthieu; Bell, David M.; Hansen, Anne-Maria Kaldal; Drozd, Greg T.; Zhang, Zhenfa; Gold, Avram; Imre, Dan; Surratt, Jason D.; Glasius, Marianne; Zelenyuk, Alla

    2016-06-07

    Multiphase chemistry of isomeric isoprene epoxydiols (IEPOX) has been shown to be the dominant source of isoprene-derived secondary organic aerosol (SOA). Recent studies have reported particles composed of ammonium bisulfate (ABS) mixed with model organics exhibit slower rates of IEPOX uptake. In the present study, we investigate the effect of atmospherically-relevant organic coatings of α-pinene (AP) SOA on the reactive uptake of trans-β-IEPOX onto ABS particles under different conditions and coating thicknesses. Single particle mass spectrometry was used to characterize in real-time particle size, shape, density, and quantitative composition before and after reaction with IEPOX. We find that IEPOX uptake by pure sulfate particles is a volume-controlled process, which results in particles with uniform concentration of IEPOX-derived SOA across a wide range of sizes. Aerosol acidity was shown to enhance IEPOX-derived SOA formation, consistent with recent studies. The presence of water has a weaker impact on IEPOX-derived SOA yield, but significantly enhanced formation of 2-methyltetrols, consistent with offline filter analysis. In contrast, IEPOX uptake by ABS particles coated by AP-derived SOA is strongly dependent on particle size and composition. IEPOX uptake occurred only when weight fraction of AP-derived SOA dropped below 50 %, effectively limiting IEPOX uptake to larger particles.

  8. Experimental determination of the H2SO4/(NH4)2SO4/H2O phase diagram.

    Science.gov (United States)

    Beyer, Keith D; Bothe, Jameson R; Burrmann, Nicola

    2007-01-25

    We have experimentally investigated the water and sulfuric acid-rich regions of the H2SO4/(NH4)2SO4/H2O ternary liquid/solid phase diagram using differential scanning calorimetry (DSC) and infrared spectroscopy of thin films. We present the liquid/solid ternary phase diagram for temperatures below 373 K and H2SO4 concentrations below 60 wt %. We have determined two ternary eutectics and two tributary reaction points for this system in the regions studied. It is also seen that sulfuric acid tetrahydrate (SAT) forms as a metastable solid over a large concentration range. Two true binary systems have been identified: ice/letovicite and SAT/ammonium bisulfate. Finally, we have compared our results to the predictions of the aerosol inorganics model and have found significant differences both in the final melting points and in the location of some of the phase boundaries including a significant discrepancy in the invariant points predicted versus those observed.

  9. New parameterization of sulfuric acid-ammonia-water ternary nucleation rates at tropospheric conditions

    Science.gov (United States)

    Merikanto, J.; Napari, I.; VehkamäKi, H.; Anttila, T.; Kulmala, M.

    2007-08-01

    Recently, the classical theory of sulfuric acid-ammonia-water (H2SO4-NH3-H2O) nucleation was reinvestigated by including the effect of stable ammonium bisulfate formation into calculations. The predicted nucleation rates lowered by many orders of magnitude, bringing them close to agreement with the available experiments on H2SO4-NH3-H2O nucleation. However, because of complex thermodynamics involved, the theoretical calculations of nucleation rates are computationally demanding, and sometimes the theory breaks down at specific concentrations and temperatures. Here we present parameterized equations of ternary H2SO4-NH3-H2O nucleation rates, critical cluster sizes, and critical cluster compositions. Our parameterizations reduce the computing time of these values by a factor of 105 compared with the calculations with the full thermodynamic model. Also, our parameterizations provide reliable estimates for ternary nucleation rates in cases when the full theory fails in isolated points of the parameter space. The parameterized nucleation rates are accurate to one order of magnitude in nucleation rate. Because of their computational efficiency, our parameterizations are particularly suitable for large-scale models of atmosphere. They are valid for temperatures above 235 K, sulfuric acid concentrations 5 · 104-109 cm-3, ammonia mixing ratios 0.1-1000 ppt, relative humidities 5%-95%, and nucleation rates over 10-5 cm-3 s-1. At these conditions, no significant nucleation occurs above 295 K.

  10. Determination of acrolein in urine by liquid chromatography and fluorescence detection of its quinoline derivative.

    Science.gov (United States)

    al-Rawithi, S; el-Yazigi, A; Nicholls, P J

    1993-11-01

    We describe an assay for acrolein in urine, employing derivatization with m-aminophenol in the presence of ferrous sulfate solution in sulfuric acid. The derivative (7-OH quinoline; DER) and the internal standard (quinine-bisulfate; IS) were separated on a 10-micron particle, 8 mm x 10-cm C18 cartridge in conjunction with a radial compression system using a mixture of 0.05 M dibasic ammonium phosphate solution (pH 2.5):acetonitrile:methanol (92:6:2) at a flow rate of 3 mL/min as a mobile phase. The effluent was monitored fluorometrically at excitation and emission wavelengths of 360 and 495 nm, respectively. The retention times of DER and IS under these conditions were 4.3 and 26 min, respectively, and no interference in the assay from any endogenous substance or other concomitantly used drug was observed. The assay was highly linear (r > 0.994) in the range 1-20 micrograms/mL of acrolein in urine (CV at different concentrations, < or = 7.9%). This method can serve to monitor acrolein pharmacokinetics in patients.

  11. Estimating the NH3:H2SO4ratio of nucleating clusters in atmospheric conditions using quantum chemical methods

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2007-02-01

    Full Text Available We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd order Møller-Plesset perturbation theory. Together with results from previous studies, we use the computed values to estimate an upper limit for the ammonia content of small atmospheric clusters, without having to explicitly include water molecules in the quantum chemical simulations. Our results indicate that the NH3:H2SO4 mole ratio of small molecular clusters in typical atmospheric conditions is probably around 1:2. High ammonia concentrations or low temperatures may lead to the formation of ammonium bisulfate (1:1 clusters, but our results rule out the formation of ammonium sulfate clusters (2:1 anywhere in the atmosphere. A sensitivity analysis indicates that the qualitative conclusions of this study are not affected even by relatively large errors in the calculation of electronic energies or vibrational frequencies.

  12. Comparative irritant potency of inhaled sulfate aerosols--effects on bronchial mucociliary clearance.

    Science.gov (United States)

    Schlesinger, R B

    1984-08-01

    The effect of 1-hr oral inhalation exposures to submicrometer aerosols of ammonium bisulfate (NH4HSO4), ammonium sulfate [NH4)2SO4), and sodium sulfate (Na2SO4) upon mucociliary clearance from the bronchial tree of rabbits was examined. Exposures to NH4HSO4 at concentrations of approximately 600-1700 micrograms/m3 produced a significant depression of clearance rate only at the highest exposure level. No significant effects were observed with the other sulfates at levels up to approximately 2000 micrograms/m3. When results were compared to those from another study in this laboratory using sulfuric acid (H2SO4) aerosol, the ranking of irritant potency was H2SO4 greater than NH4HSO4 greater than (NH4)2SO4, Na2SO4. Alteration in bronchial mucociliary clearance due to sulfate aerosols appears to be related to the deposition of [H+] on the mucus lining of conducting airways.

  13. Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods

    Science.gov (United States)

    Kurtén, T.; Torpo, L.; Sundberg, M. R.; Kerminen, V.-M.; Vehkamäki, H.; Kulmala, M.

    2007-05-01

    We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd order Møller-Plesset perturbation theory). Together with results from previous studies, we use the computed values to estimate an upper limit for the ammonia content of small atmospheric clusters, without having to explicitly include water molecules in the quantum chemical simulations. Our results indicate that the NH3:H2SO4 mole ratio of small molecular clusters in typical atmospheric conditions is probably around 1:2. High ammonia concentrations or low temperatures may lead to the formation of ammonium bisulfate (1:1) clusters, but our results rule out the formation of ammonium sulfate clusters (2:1) anywhere in the atmosphere. A sensitivity analysis indicates that the qualitative conclusions of this study are not affected even by relatively large errors in the calculation of electronic energies or vibrational frequencies.

  14. Carbonaceous Matter in Growing Nanoparticles

    Science.gov (United States)

    Johnston, M. V.; Stangl, C. M.; Horan, A. J.

    2015-12-01

    Atmospheric nanoparticles constitute the greatest portion of ambient aerosol loading by number. A major source of atmospheric nanoparticles is new particle formation (NPF), a gas to particle conversion process whereby clusters nucleate from gas phase precursors to form clusters on the order of one or a few nanometers and then grow rapidly to climatically relevant sizes. A substantial fraction of cloud condensation nuclei (CCN) are thought to arise from NPF. In order to better predict the frequency, growth rates, and climatic impacts of NPF, knowledge of the chemical mechanisms by which nucleated nanoparticles grow is needed. The two main contributors to particle growth are (neutralized) sulfate and carbonaceous matter. Particle growth by sulfuric acid condensation is generally well understood, though uncertainty remains about the extent of base neutralization and the relative roles of ammonia and amines. Much less is known about carbonaceous matter, and field measurements suggest that nitrogen-containing species are important. In this presentation, recent work by our group will be described that uses a combination of ambient measurements, laboratory experiments and computational work to study carbonaceous matter in growing nanoparticles. These studies span a range of particle sizes from the initial adsorption of molecules onto a nanometer-size ammonium bisulfate seed cluster to reactions in particles that are large enough to support condensed-phase chemistry.

  15. Investigations of gas-to-particle conversion in the atmosphere

    Science.gov (United States)

    Juozaitis, Arvydas; Trakumas, Saulius; Girgždien≐, Rasa; Girgždys, Aloyzas; Šopauskien≐, Dalia; Ulevičius, Vidmantas

    Continental aerosol particle size distributions were measured as a function of time at the] background station Aisetas and in the suburb of Vilnius. Marine aerosol particle formation was studied in outdoor photochemical chamber experiments performed on the coast of the Baltic sea. The functional dependence of the particle diameter growth rate on the particle size was calculated from the aerosol particle size distribution data and was compared with the theoretical predictions for the particle growth due to vapor condensation or due to the adsorption of aerosol precursor gases on the particle surface or within an airborne droplet. It was shown that during summer months condensation of low pressure vapors formed by gas phase homogeneous chemical reactions was predominant mechanism of the continental aerosol particle growth. While in winter growth of a submicrometer continental aerosol particle was frequently governed by two competing processes: condensation of low pressure vapors and heterogeneous oxidation of aerosol precursor gases inside the liquid droplet. Ozone was found to be an active oxidant in the heterogeneous aqueous phase chemical reactions. The outdoor photochemical chamber experiments showed that aqueous phase chemical reactions were responsible for the formation of marine sulfuric acid aerosol particles from the dimethylsulfide. After these particles were partially neutralized by ammonia to the ammonium sulfate or bisulfate, their further growth was observed to be surface limited.

  16. Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2007-05-01

    Full Text Available We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd order Møller-Plesset perturbation theory. Together with results from previous studies, we use the computed values to estimate an upper limit for the ammonia content of small atmospheric clusters, without having to explicitly include water molecules in the quantum chemical simulations. Our results indicate that the NH3:H2SO4 mole ratio of small molecular clusters in typical atmospheric conditions is probably around 1:2. High ammonia concentrations or low temperatures may lead to the formation of ammonium bisulfate (1:1 clusters, but our results rule out the formation of ammonium sulfate clusters (2:1 anywhere in the atmosphere. A sensitivity analysis indicates that the qualitative conclusions of this study are not affected even by relatively large errors in the calculation of electronic energies or vibrational frequencies.

  17. A survey of effects of gaseous and aerosol pollutants on pulmonary function of normal males.

    Science.gov (United States)

    Stacy, R W; Seal, E; House, D E; Green, J; Roger, L J; Raggio, L

    1983-01-01

    A total of 231 normal male human subjects were exposed for 4 hr to air, ozone, nitrogen dioxide, or sulfur dioxide; to sulfuric acid, ammonium bisulfate, ammonium sulfate, or ammonium nitrate aerosols; or to mixtures of these gaseous and aerosol pollutants. Only one concentration of each pollutant was used. This study, therefore, represents a preliminary survey, intended to allow direct comparison of studies to plan future research. During exposure each subject had two 15-min exercise sessions on a treadmill at 4 mph and 10% grade. Environmental conditions were mildly stressful, i.e., temperature = 30 degrees C and relative humidity = 60%. A battery of 19 measurements of pulmonary function was performed just prior to exposure (air control); 2 hr into the exposure, following the first exercise session; 4 hr into the exposure, following the second exercise session; and 24 hr after exposure. Significant differences were noted in specific airway resistance (SRAW), forced vital capacity (FVC), and forced expiratory flow at 50% of FVC (FEF50) and in related measurements in those experimental groups exposed to ozone or to ozone plus aerosols. None of the aerosols alone, nitrogen dioxide or sulfur dioxide alone, or mixtures of nitrogen dioxide or sulfur dioxide with aerosols produced significant effects. A distribution analysis of subject responsivity to ozone gave a normal distribution among subjects not exposed to ozone, and a distribution shifted to the right and skewed to the right among those exposed to ozone alone or in mixture, with no evidence of bimodal distribution of ozone sensitivity.

  18. The nature and origins of acid summer haze air pollution in metropolitan Toronto, Ontario.

    Science.gov (United States)

    Thurston, G D; Gorczynski, J E; Currie, J H; He, D; Ito, K; Hipfner, J; Waldman, J; Lioy, P J; Lippmann, M

    1994-05-01

    During July and August of 1986, 1987, and 1988, a field study was conducted of ambient acidic aerosol levels in Toronto, Ontario. Fine particle mass (da acidity (H+) and sulfate (SO4 =). Two additional H(+)-monitoring sites were concurrently operated during the summers of 1986 and 1987 to examine the spatial variability of H+ within the metropolitan area. During the summer of 1986, a quasi-continuous total sulfate/sulfuric acid analyzer was also deployed to allow a determination of the chemical form of H+. Results indicate that acid aerosol episodes (H+ > or = 100 nmole/m3) did occur in this city during the summer months, and that H+ peaks were well correlated with sulfate peaks. Virtually all of the H+ was found to be present as ammonium bisulfate (NH4HSO4). While H+ concentrations were highly correlated among the three monitoring sites (r = 0.9), the highest H+/SO4 = ratios prevailed during SO4 = episode periods and at the least urbanized site. This latter trend was apparently due to greater neutralization of H+ by local ammonia at the more urbanized sites. Comparisons of day vs night H+/SO4 = ratios, an examination of air mass back-trajectories, and contemporaneous H+ measurements at surrounding sites collectively indicated that transported regional haze air pollution from the United States is a major contributor to the H+ events recorded within Toronto.

  19. A Laboratory Study on the Phase Transition for Polar Stratospheric Cloud Particles

    Science.gov (United States)

    Teets, Edward H., Jr.

    1997-01-01

    The nucleation and growth of different phases of simulated polar stratospheric cloud (PSC) particles were investigated in the laboratory. Solutions and mixtures of solutions at concentrations 1 to 5 m (molality) of ammonium sulfate, ammonium bisulfate, sodium chloride, sulfuric acid, and nitric acid were supercooled to prescribed temperatures below their equilibrium melting point. These solutions were contained in small diameter glass tubing of volumes ranging from 2.6 to 0.04 ml. Samples were nucleated by insertion of an ice crystal, or in some cases by a liquid nitrogen cooled wire. Crystallization velocities were determined by timing the crystal growth front passages along the glass tubing. Solution mixtures containing aircraft exhaust (soot) were also examined. Crystallization rates increased as deltaT2, where deltaT is the supercooling for weak solutions (2 m or less). The higher concentrated solutions (greater than 3 m) showed rates significantly less than deltaT2. This reduced rate suggested an onset of a glass phase. Results were applied to the nucleation of highly concentrated solutions at various stages of polar stratospheric cloud development within the polar stratosphere.

  20. Hygroscopic behavior of partially volatilized coastal marine aerosols using the volatilization and humidification tandem differential mobility analyzer technique

    Science.gov (United States)

    Johnson, G. R.; Ristovski, Z. D.; D'Anna, B.; Morawska, L.

    2005-10-01

    Coastal marine nucleation, Aitken, and accumulation mode aerosol particles with back trajectories indicative of marine origin were examined using a volatilization and humidification tandem differential mobility analyzer (VHTDMA) to reveal the volatilization temperatures of the various component species. The diameter hygroscopic growth factors of the residue particles were continually examined throughout the volatilization process. In each of the three modes the dominant particle type appeared to be composed of the same four physicochemically distinct species though in different ratios. These species exhibited volatility and hygroscopic behavior consistent with combinations of a volatile organic species, sulfuric acid, ammonium sulfate or bisulfate, iodine oxide, and an insoluble nonvolatile residue. The Aitken and accumulation mode aerosols contain large fractions of the insoluble, volatile, organic-like material, and the volatilization of this species results in a distinct increase in the water volume uptake of the particles. Of the four distinct species, only the sulfuric acid-like species constituted an increasing volume fraction with decreasing particle size. This finding indicates that nucleation mode particles constitute an acidic seed and as such would undergo acid-catalyzed secondary organic aerosol growth at a faster rate. The lack of a nonvolatile hygroscopic residue consistent with sea salt in these particles implies that the aerosolization of seawater is not the dominant production mechanism for these submicrometer coastal marine aerosols.

  1. Parameterization of the Optical Properties of Sulfate Aerosols in the Infrared.

    Science.gov (United States)

    Li, J.; Min, Qilong

    2002-11-01

    Parameterizations of absorptance depth for ammonium sulfate [(NH4)2SO4], ammonium bisulfate (NH4HSO4), and sulfuric acid (H2SO4) in the infrared are provided for an eight-band model (covering 340-2500 cm1) and for 32 individual wavenumbers in order to generate other band schemes. The parameterization is simple in form and in its dependence on relative humidity.It is found that the aerosol surface infrared forcing can cancel about 12%-24% aerosol surface solar forcing in a clear sky condition. Also the existence of clouds could enhance the ratio of aerosol surface infrared forcing to the aerosol surface solar forcing. In contrast to the solar case, a small mode size distribution does not always produce a larger aerosol surface forcing. Also it is found that the aerosol surface forcing is dependent on the aerosol location. Very simple analysis is presented to help understand the related physics on sulfate aerosol infrared radiative forcing.

  2. The measurement of H 2SO 4 and other sulfate species at Tuxedo, New York with a thermal analysis flame photometric detector and simultaneously collected quartz filter samples

    Science.gov (United States)

    Morandi, Maria T.; Kneip, Theo J.; Geoffery Cobourn, W.; Husar, Rudolf B.; Lioy, Paul J.

    A study of major atmospheric particulate sulfate species was conducted during 30 July 1980-1983 September 1980 in Sterling Forest, a rural area in Tuxedo, NY, not affected by major local sources of pollution. In situ measurements of total sulfate, sulfuric acid and ammonium sulfate ammonium bisulfate were made using Thermal Analysis-Flame Photometric Detection (TA-FPD). These measurements were compared to the total sulfate and strong acid (H +) concentration measured in simultaneously collected 12 h, treated quartz filter samples. The concentration of NH 4HSO 4 was inferred from the difference between the total strong acid concentration and the sulfuric acid measurements, so that total sulfate and acid concentrations could be balanced. A major sulfate pollution episode occurred during the period of 27-29 August. The concentration of H + showed an excess above that necessary to account for the TA-FPD H 2SO 4 measurement, indicating the presence of NH 4 HSO 4. The maximum 12 h average concentrations of H 2SO 4, NH 4HSO 4 and (NH 4) 2SO 4 were 5.18, 11.42 and 10.08 μg m -3 as SO 42- respectively, and were measured from 9:15 to 21:15 on 28 August. The study demonstrated the usefulness of concurrent measurements of airborne particulate sulfate by filter extraction and TA-FPD to identify acidic sulfate species.

  3. An ambient experimental study of phase equilibrium in the atmospheric system: Aerosol H +, NH 4+, SO 2-4, NO 3--NH 3(g), HNO 3(g)

    Science.gov (United States)

    Tanner, Roger L.

    A major simplification in the quantitative modeling of the atmospheric impact of the major aerosol and gaseous sulfur and nitrogen compounds would result from demonstration of phase equilibrium between the gases NH 3, HNO 3 and the appropriate aerosol-phase ionic or molecular species in the ambient atmosphere. The phase diagram of the (NH 4) 2SO 4-H 2SO 4-H 2O and NH 4NO 3-H 2O systems have been recently refined by experimental measurements and preliminary calculations of the mixed nitrate-sulfate system have also been made. Experiments to test the applicability of existing phase equilibria considerations to the ambient atmosphere have been designed and conducted based on newly devised techniques for continuous determination of gaseous NH 3 with time resolution acid and aerosol nitrate with time resolution of ~ 15 min. Preliminary results suggest that during a daytime period with aerosol composition approximating a letovicite-NH 4NO 3 mixture, observed products of NH 3 (g) and HNO 3(g) concentrations agreed very well with the equilibrium constant calculated for the ammonium nitrate-NH 3(g), HNO 3(g) equilibrium. During a night-time period, the predicted ammonia concentrations, based on bulk aerosol composition data, were much lower and nitric acid concentrations much higher, respectively, than the observed values. The error sources in the measured and calculated values do not appear to account for the apparent deviations from gas-phase concentrations based on the droplet-pH controlling bisulfate-sulfate equilibrium.

  4. Effects of brief and intermediate exposures to sulfate submicron aerosols and sulfate injections on cardiopulmonary function of dogs and tracheal mucous velocity of sheep

    Energy Technology Data Exchange (ETDEWEB)

    Sackner, M.A. (Mount Sinai Medical Center, Miami Beach, FL); Dougherty, R.L.; Chapman, G.A.; Cipley, J.; Perez, D.; Kwoka, M.; Reinhart, M.; Brito, M.; Schreck, R.

    1981-06-01

    Pulmonary mechanics of anesthetized dogs were not changed or were minimally altered by breathing the following compounds as submicron aerosols in concentrations up to 17.3 mg/m/sup 3/ for 7.5 min: (1) sodium chloride (as a control), (2) sodium sulfate, (3) ammonium sulfate, (4) zinc sulfate, (5) zinc ammonium sulfate, (6) ammonium bisulfate, (7) aluminum sulfate, (8) manganese sulfate, (9) nickel sulfate, (10) copper sulfate, (11) ferrous fulfate, and (12) ferric sulfate. Submicron aerosols of these compounds in concentrations of 4.1 to 8.8 mg/m/sup 3/, administered for 4 h to anesthetized dogs, did not affect mechanics of breathing, hemodynamics, and arterial blood gases. In conscious sheep, tracheal mucous velocity was not altered by exposure to the submicron aerosols of the sulfate compounds. None of these compounds, injected iv in a dose of 1 mg, had adverse effects on mechanics of breathing, pulmonary and systemic hemodynamics, or arterial blood gases. In 100-mg injections, zinc sulfate and zinc ammonium sulfate produced a fall in cardiac output, systemic hypotension, hypoxemia, and metabolic acidosis. Copper sulfate at this dose produced pulmonary hypertension, a fall in cardiac output, hypoxemia, respiratory acidosis, and a decrease of specific total respiratory conductance. It is concluded that submicron aerosols of sulfate salts do not have adverse cardiopulmonary effects when administered in high concentrations for up to 4 h. However, prolonged exposure to high concentrations of zinc sulfate, zinc ammonium sulfate, and copper sulfate aerosols might have adverse cardiopulmonary effects.

  5. Diet folate, DNA methylation and polymorphisms in methylenetetrahydrofolate reductase in association with the susceptibility to gastric cancer.

    Science.gov (United States)

    Gao, Shang; Ding, Li-Hong; Wang, Jian-Wei; Li, Cun-Bao; Wang, Zhao-Yang

    2013-01-01

    Methylenetetrahydrofolate reductase (MTHFR) has been reported to be associated with DNA methylation, an epigenetic feature frequently found in gastric cancer. We conducted a case-control study to explore the association of MTHFR C677T polymorphisms with gastric cancer risk and its relation with the DNA methylation of COX-2, MGMT, and hMLH1 genes. Genotyping of P16, MGMT and HMLH1 was determined by methylation-specific PCR after sodium bisulfate modification of DNA, and genotyping of MTHFR C677T was conducted by TaqMan assays using the ABI Prism 7911HT Sequence Detection System. Folate intake was calculated with the aid of a questionnaire. Compared with the MTHFR 677CC genotype, the TT genotype was significantly associated with 2.08 fold risk of gastric cancer when adjusting for potential risk factors. Individuals who had an intake of folate above 310 μg/day showed protective effects against gastric cancer risk. The effect of MTHFR C677T polymorphisms on the risk of gastric cancer was modified by folate intake and methylation status of MGMT (P for interaction <0.05).

  6. A method for detecting the presence of organic fraction in nucleation mode sized particles

    Directory of Open Access Journals (Sweden)

    P. Vaattovaara

    2005-06-01

    Full Text Available New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm and the lower end of Aitken mode particles (d≤50 nm is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer method to shed light on the presence of organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

  7. A method for detecting the presence of organic fraction in nucleation mode sized particles

    Directory of Open Access Journals (Sweden)

    P. Vaattovaara

    2005-01-01

    Full Text Available New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm and the lower end of Aitken mode particles (d≤50 nm is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer method to shed light on the presence of an organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10 nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

  8. Standard practice for preparation and dissolution of plutonium materials for analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice is a compilation of dissolution techniques for plutonium materials that are applicable to the test methods used for characterizing these materials. Dissolution treatments for the major plutonium materials assayed for plutonium or analyzed for other components are listed. Aliquants of the dissolved samples are dispensed on a weight basis when one of the analyses must be highly reliable, such as plutonium assay; otherwise they are dispensed on a volume basis. 1.2 The treatments, in order of presentation, are as follows: Procedure Title Section Dissolution of Plutonium Metal with Hydrochloric Acid 9.1 Dissolution of Plutonium Metal with Sulfuric Acid 9.2 Dissolution of Plutonium Oxide and Uranium-Plutonium Mixed Oxide by the Sealed-Reflux Technique 9.3 Dissolution of Plutonium Oxide and Uranium-Plutonium Mixed Oxides by Sodium Bisulfate Fusion 9.4 Dissolution of Uranium-Plutonium Mixed Oxides and Low-Fired Plutonium Oxide in Beakers 9.5 1.3 The values stated in SI units are to be re...

  9. Non-Complexing Anions for Quantitative Speciation Studies Using Raman Spectroscopy in Fused Silica High-Pressure Optical Cells Under Hydrothermal Conditions.

    Science.gov (United States)

    Applegarth, Lucas M S G A; Alcorn, Christopher; Bissonette, Katherine; Noël, John; Tremaine, Peter R

    2015-08-01

    This paper reports methods for obtaining time-dependent reduced isotropic Raman spectra of aqueous species in quartz capillary high-pressure optical cells under hydrothermal conditions, as a means of determining quantitative speciation in hydrothermal fluids. The methods have been used to determine relative Raman scattering coefficients and to examine the thermal decomposition kinetics of the non-complexing anions bisulfate (HSO4(-)), perchlorate (CIO4(-)), perrhenate (ReO4(-)), and trifluoromethanesulfonate, or "triflate" (CF3SO3(-)) in acidic and neutral solutions at temperatures up to 400°C and 30 MPa. Arrhenius expressions for calculating the thermal decomposition rate constants are also reported. Thermal stabilities in the acidic solutions followed the order HSO4(-) (stable) > ReO4(-) > CIO4(-) > CF3SO3(-), with half-lives (t1/2) > 7 h at 300°C. In neutral solutions, the order was HSO4(-) (stable) > CF3SO3(-) > ReO4(-) > CIO4(-), with t1/2 > 8 h at 350°C. CF3SO3(-) was extremely stable in neutral solutions, with t1/2 > 11 h at 400°C.

  10. Selective Methane Oxidation Catalyzed by Platinum Salts in Oleum at Turnover Frequencies of Large-Scale Industrial Processes.

    Science.gov (United States)

    Zimmermann, Tobias; Soorholtz, Mario; Bilke, Marius; Schüth, Ferdi

    2016-09-28

    Direct catalytic methane functionalization, a "dream reaction", is typically characterized by relatively low catalyst activities. This also holds for the η(2)-(2,2'-bipyrimidyl)dichloroplatinum(II) [(bpym)PtCl2, 1] catalyst which oxidizes methane to methyl bisulfate in sulfuric acid. Nevertheless, it is arguably still one of the best systems for the partial oxidation of methane reported so far. Detailed studies of the dependence of activity on the SO3 concentration and the interplay with the solubility of different platinum compounds revealed potassium tetrachloroplatinate (K2PtCl4) as an extremely active, selective, and stable catalyst, reaching turnover frequencies (TOFs) of more than 25,000 h(-1) in 20% oleum with selectivities above 98%. The TOFs are more than 3 orders of magnitude higher compared to the original report on (bpym)PtCl2 and easily reach or exceed those realized in commercial industrial processes, such as the Cativa process for the carbonylation of methanol. Also space-time-yields are on the order of large-scale commercialized processes.

  11. Aberrant Expression of Xist in Aborted Porcine Fetuses Derived from Somatic Cell Nuclear Transfer Embryos

    Directory of Open Access Journals (Sweden)

    Lin Yuan

    2014-11-01

    Full Text Available Cloned pigs generated by somatic cell nuclear transfer (SCNT show a greater ratio of early abortion during mid-gestation than normal controls. X-linked genes have been demonstrated to be important for the development of cloned embryos. To determine the relationship between the expression of X-linked genes and abortion of cloned porcine fetuses, the expression of X-linked genes were investigated by quantitative real-time polymerase chain reaction (q-PCR and the methylation status of Xist DMR was performed by bisulfate-specific PCR (BSP. q-PCR analysis indicated that there was aberrant expression of X-linked genes, especially the upregulated expression of Xist in both female and male aborted fetuses compared to control fetuses. Results of BSP suggested that hypomethylation of Xist occurred in aborted fetuses, whether male or female. These results suggest that the abnormal expression of Xist may be associated with the abortion of fetuses derived from somatic cell nuclear transfer embryos.

  12. WBSA: web service for bisulfite sequencing data analysis.

    Science.gov (United States)

    Liang, Fang; Tang, Bixia; Wang, Yanqing; Wang, Jianfeng; Yu, Caixia; Chen, Xu; Zhu, Junwei; Yan, Jiangwei; Zhao, Wenming; Li, Rujiao

    2014-01-01

    Whole-Genome Bisulfite Sequencing (WGBS) and genome-wide Reduced Representation Bisulfite Sequencing (RRBS) are widely used to study DNA methylation. However, data analysis is complicated, lengthy, and hampered by a lack of seamless analytical pipelines. To address these issues, we developed a convenient, stable, and efficient web service called Web Service for Bisulfite Sequencing Data Analysis (WBSA) to analyze bisulfate sequencing data. WBSA focuses on not only CpG methylation, which is the most common biochemical modification in eukaryotic DNA, but also non-CG methylation, which have been observed in plants, iPS cells, oocytes, neurons and stem cells of human. WBSA comprises three main modules as follows: WGBS data analysis, RRBS data analysis, and differentially methylated region (DMR) identification. The WGBS and RRBS modules execute read mapping, methylation site identification, annotation, and advanced analysis, whereas the DMR module identifies actual DMRs and annotates their correlations to genes. WBSA can be accessed and used without charge either online or local version. WBSA also includes the executables of the Portable Batch System (PBS) and standalone versions that can be downloaded from the website together with the installation instructions. WBSA is available at no charge for academic users at http://wbsa.big.ac.cn.

  13. What Is Eating Ozone? Thermal Reactions between SO2 and O3: Implications for Icy Environments

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2016-12-01

    Laboratory studies are presented, showing for the first time that thermally driven reactions in solid H2O + SO2 + O3 mixtures can occur below 150 K, with the main sulfur-containing product being bisulfate ({{{HSO}}4}-). Using a technique not previously applied to the low-temperature kinetics of either interstellar or solar-system ice analogs, we estimate an activation energy of 32 kJ mol-1 for {{{HSO}}4}- formation. These results show that at the temperatures of the Jovian satellites, SO2 and O3 will efficiently react making detection of these molecules in the same vicinity unlikely. Our results also explain why O3 has not been detected on Callisto and why the SO2 concentration on Callisto appears to be highest on that world’s leading hemisphere. Furthermore, our results predict that the SO2 concentration on Ganymede will be lowest in the trailing hemisphere, where the concentration of O3 is the highest. Our work suggests that thermal reactions in ices play a much more important role in surface and sub-surface chemistry than generally appreciated, possibly explaining the low abundance of sulfur-containing molecules and the lack of ozone observed in comets and interstellar ices.

  14. Determination of atmospheric gaseous and particulate sulfur compounds. [Atmospheric SO/sub 2/ sampling, calibration, and data processing

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.L.; Forrest, J.; Newman, L.

    1977-01-01

    The corrosive influence of atmospheric sulfur compounds to man's health and his environment has been demonstratably costly. Damage to building materials, textiles, animals, plants, and artworks have been well documented and can in some cases be directly translated into financial loss. Indirect effects such as contribution to respiratory disease and increased death rates are more subtle but no less real. For both economic and ecological reasons, it has become imperative that atmospheric concentrations be minimized. Anthropogenic sources of atmospheric sulfur compounds are principally the combustion of fossil fuels, which produce sulfur dioxide along with several percent of sulfur trioxide. The predominant form of atmospheric gaseous sulfur is sulfur dioxide, accompanied by small amounts of hydrogen sulfide and organic sulfur compounds such as mercaptans and sulfides. Aerosol sulfur exists primarily as sulfates, including bisulfate and sulfuric acid. The core of any monitoring system is the analytical instrument or technique. Methods for SO/sub 2/ sampling, calibration, and data acquisition and reduction are reviewed. 305 references.

  15. Formation of Secondary Particulate Matter by Reactions of Gas Phase Hexanal with Sulfate Aerosol Particles

    Science.gov (United States)

    Zhang, J.

    2003-12-01

    The formation of secondary particulate matter from the atmospheric oxidation of organic compounds can significantly contribute to the particulate burden, but the formation of organic secondary particulate matter is poorly understood. One way of producing organic secondary particulate matter is the oxidation of hydrocarbons with seven or more carbon atoms to get products with low vapor pressure. However, several recent reports suggest that relatively low molecular weight carbonyls can enter the particle phase by undergoing heterogeneous reactions. This may be a very important mechanism for the formation of organic secondary particulate matter. Atmospheric aldehydes are important carbonyls in the gas phase, which form via the oxidation of hydrocarbons emitted from anthropogenic and biogenic sources. In this poster, we report the results on particle growth by the heterogeneous reactions of hexanal. A 5 L Continuous Stirred Tank Reactor (CSTR) is set up to conduct the reactions in the presence of seed aerosol particles of deliquesced ammonia bisulfate. Hexanal is added into CSTR by syringe pump, meanwhile the concentrations of hexanal are monitored with High Pressure Liquid Chromatograph (HPLC 1050). A differential Mobility Analyzer (TSI 3071) set to an appropriate voltage is employed to obtain monodisperse aerosols, and another DMA associated with a Condensation Nuclear Counter (TSI 7610) is used to measure the secondary particle size distribution by the reaction in CSTR. This permits the sensitive determination of particle growth due to the heterogeneous reaction, very little growth occurs when hexanal added alone. Results for the simultaneous addition of hexanal and alcohols will also be presented.

  16. Influence of sulfur in fuel on the properties of diffusion flame soot

    Science.gov (United States)

    Zhao, Yan; Ma, Qingxin; Liu, Yongchun; He, Hong

    2016-10-01

    Previous studies indicate that sulfur in fuel affects the hygroscopicity of soot. However, the issue of the effect of sulfur in fuel on soot properties is not fully understood. Here, the properties of soot prepared from fuel with a variable sulfur content were investigated under lean and rich flame conditions. Lean flame soot was influenced more by sulfur in fuel than rich flame soot. The majority of sulfur in fuel in lean flame was converted to gaseous SO2, while a small fraction appeared as sulfate and bisulfate (referred to as sulfate species) in soot. As the sulfur content in fuel increased, sulfate species in lean flame soot increased nonlinearly, while sulfate species on the surface of lean flame soot increased linearly. The hygroscopicity of lean flame soot from sulfur-containing fuel was enhanced mainly due to sulfate species. Meanwhile, more alkynes were formed in lean flame. The diameter of primary lean flame soot particles increased and accumulation mode particle number concentrations of lean flame soot from sulfur-containing fuel increased as a result of more alkynes. Because the potential effects of soot particles on air pollution development greatly depend on the soot properties, which are related to both chemical aging and combustion conditions, this work will aid in understanding the impacts of soot on air quality and climate.

  17. Bifunctional Crosslinking Agents Enhance Anion Exchange Membrane Efficacy for Vanadium Redox Flow Batteries.

    Science.gov (United States)

    Wang, Wenpin; Xu, Min; Wang, Shubo; Xie, Xiaofeng; Lv, Yafei; Ramani, Vijay K

    2014-06-01

    A series of cross-linked fluorinated poly (aryl ether oxadiazole) membranes (FPAEOM) derivatized with imidazolium groups were prepared. Poly (N-vinylimidazole) (PVI) was used as the bifunctional cross-linking agent to: a) lower vanadium permeability, b) enhance dimensional stability, and c) concomitantly provide added ion exchange capacity in the resultant anion exchange membranes. At a molar ratio of PVI to FPAEOM of 1.5, the resultant membrane (FPAEOM-1.5 PVI) had an ion exchange capacity of 2.2 meq g-1, a vanadium permeability of 6.8×10-7 cm2 min-1, a water uptake of 68 wt.%, and an ionic conductivity of 22.0 mS cm-1, all at 25°C. Single cells prepared with the FPAEOM-1.5 PVI membrane exhibited a higher coulombic efficiency (> 92%) and energy efficiency (> 86%) after 40 test cycles in vanadium redox flow battery. The imidazolium cation showed high chemical stability in highly acidic and oxidizing vanadium solution as opposed to poor stability in alkaline solutions. Based on our DFT studies, this was attributed to the lower HOMO energy (-7.265 eV) of the HSO4- ion (compared to the OH- ion; -5.496 eV) and the larger HOMO-LUMO energy gap (6.394 eV) of dimethylimidazolium bisulfate ([DMIM] [HSO4]) as compared to [DMIM] [OH] (5.387 eV).

  18. Electrostatically Embedded Many-Body Approximation for Systems of Water, Ammonia, and Sulfuric Acid and the Dependence of Its Performance on Embedding Charges.

    Science.gov (United States)

    Leverentz, Hannah R; Truhlar, Donald G

    2009-06-09

    This work tests the capability of the electrostatically embedded many-body (EE-MB) method to calculate accurate (relative to conventional calculations carried out at the same level of electronic structure theory and with the same basis set) binding energies of mixed clusters (as large as 9-mers) consisting of water, ammonia, sulfuric acid, and ammonium and bisulfate ions. This work also investigates the dependence of the accuracy of the EE-MB approximation on the type and origin of the charges used for electrostatically embedding these clusters. The conclusions reached are that for all of the clusters and sets of embedding charges studied in this work, the electrostatically embedded three-body (EE-3B) approximation is capable of consistently yielding relative errors of less than 1% and an average relative absolute error of only 0.3%, and that the performance of the EE-MB approximation does not depend strongly on the specific set of embedding charges used. The electrostatically embedded pairwise approximation has errors about an order of magnitude larger than EE-3B. This study also explores the question of why the accuracy of the EE-MB approximation shows such little dependence on the types of embedding charges employed.

  19. 合成β-萘乙醚的研究进展%Research progress of synthesis of β-naphthyl ethyl ether

    Institute of Scientific and Technical Information of China (English)

    俞善信; 文瑞明; 刘美艳

    2013-01-01

    β-Naphthyl ethyl ether is a very good flavor。 Research into synthetic catalyst of β-naphthyl ethyl ether will have greatly influence to production of β-naphthyl ethyl ether. The synthesis of β-naphthyl ethyl ether with Williamson method and β-naphthol-ethyl alcohol etherification during the last years was reviewed. The result showed that solid acids(p-toluene sulfonic acid,ferric chloride,copper chloride,aluminum sulfate,ferric sulfate and sodium bisulfate et al. )are good catalyst for synthesis of β-naphthyl ethyl ether from β-naphthol and ethyl alcohol etherification.%β-萘乙醚是一种很好的香料.合成β-萘乙醚催化剂的研究对于β-萘乙醚的生产具有重大影响.评述了近年来合成β-萘乙醚的Williamson法和β-萘酚-乙醇醚化法.结果表明,固体酸(对甲苯磺酸、三氯化铁、氯化铜、硫酸铝、硫酸铁和硫酸氢钠等)是由β-萘酚和乙醇醚化合成β-萘乙醚的良好催化剂.

  20. Acetone-soluble cellulose acetate extracted from waste blended fabrics via ionic liquid catalyzed acetylation.

    Science.gov (United States)

    Sun, Xunwen; Lu, Canhui; Zhang, Wei; Tian, Dong; Zhang, Xinxing

    2013-10-15

    Isolation of cellulose from waste polyester/cotton blended fabrics (WBFs) is a bottleneck for recycling and exploiting waste textiles. The objective of this study was to provide a new environmental-friendly and efficient approach for extracting cellulose derivatives and polyester from WBFs. A Bronsted acidic ionic liquid (IL) N-methyl-imidazolium bisulfate, [Hmim]HSO4, was used as a novel catalyst for acetylation of cellulose rather than a solvent with the aim to overcome low isolation efficiency associated with the very high viscosity and relatively high costs of ILs. The extraction yield of acetone-soluble cellulose acetate (CA) was 49.3%, which corresponded to a conversion of 84.5% of the cellulose in the original WBFs; meanwhile, 96.2% of the original poly(ethylene terephthalate) (PET) was recovered. The extracted CA was characterized by (1)H NMR, FTIR, XRD and TGA analysis, and the results indicated that high purity acetone-soluble CA and carbohydrate-free PET could be isolated in this manner from WBFs.

  1. Decitabine treatment could ameliorate primary iron-overload in myelodysplastic syndrome patients.

    Science.gov (United States)

    Shucheng, Gu; Chunkang, Chang; Youshan, Zhao; Juan, Guo; Chengming, Fei; Xi, Zhang; Chao, Xiao; Xiao, Li

    2015-04-01

    In order to research how does hypomethylating agents ameliorate iron metabolism in myelodysplastic syndrome (MDS), we performed methylation-specific, polymerase chain reaction (MSP), bisulfate genomic sequencing polymerase chain reaction (BSP), quantitative real-time PCR and western blot of hemojuvelin (HJV) and ELISA assay for hepcidin before and after demethylating therapy (decitabine) to determine whether the change of HJV methylation status would have an influence on hepcidin expression. Eleven of 22 MDS patients achieved CR or PR according to IWG criteria (50%). HJV mRNA was induced in decitabine responders (p = .006 comparing pre/post decitabine treatment) but not in non-responders (p = .121). Similarly, hepcidin serum expression increased from 320.77 ± 34.8 μg/L to 366.77 ± 21.90 μg/L (p = .012) in responders but did not significantly change in non-responders (p = .058), while no difference of adjusted serum ferritin (ASF) was found. In conclusion, hypermethylation of HJV promoter region could silence the gene expression and demethylating therapy might ameliorate iron-overload through HJV demethylation.

  2. An Experimental Study of Single Suspended H2so4/nh3/h2o-aerosols : Atmospheric Relevance of Letovicite

    Science.gov (United States)

    Colberg, C. A.; Krieger, U. K.; Luo, B.; Wernli, H.; Peter, Th.

    letovicite and ammonium sulfate, which often exist as mixed-phase (solid/liquid) particles. Ammonium bisulfate is not de- tected in the electrodynamic trap. Moreover the results suggest that a new, hitherto unknown phase is observed during the experiments. In supporting experiments the new phase is identified as ammonium bisulfate monohydrate. Efflorescence usually takes place at RH eters: NH+/SO24 -ratios of a GCM-study by Adams et al. [1999] and global RH-values - 4 determined from ECMWF-data by Wernli [2001]. NH+/SO24 -ratios and RH-values - 4 are followed along trajectories, calculated from ECMWF-data Wernli [2001]. In the present work a new model which combines the three data-sets is developed. Results indicate that a significant fraction of the ammoniate sulfate aerosols contain solids over large regions in the whole atmosphere, most likely in the form of letovicite. Be- cause of the varying stoichiometries of atmospheric aerosols it is expected that they form multiphase aerosols upon crystallization. The three major implications of the present work are: Crystalline ammoniated sulfate particles, especially letovicite, are very likely to occur throughout the whole atmosphere. These aerosols are not expected to be pure solids but mixtures of one or more solids and a remaining liquid. The morphologies of these aerosols are probably very diverse and complex and, hence, not easily predictable. Based on the experiments of this work letovicite appears to be an atmospherically very important phase whereas most earlier studies discuss only the relevance

  3. PCI for Unstable Angina in Elderly Patients%PCI 治疗高龄不稳定性心绞痛的疗效

    Institute of Scientific and Technical Information of China (English)

    涂晓文; 苏涛; 黄国明; 王洪如; 乔怀宇

    2015-01-01

    目的:探讨经皮冠状动脉介入(PCI)治疗高龄不稳定性心绞痛的临床疗效。方法将118例不稳定性心绞痛患者按是否行 PCI 治疗分为2组:PCI 组(65例)和 ODT 组(53例)。PCI 组患者采用 PCI 治疗,术后采用阿司匹林肠溶片、硫酸氢氯吡格雷治疗。ODT 组患者采用阿司匹林肠溶片、硫酸氢氯吡格雷治疗,同时采用单纯优化药物治疗。观察2组患者治疗6个月后血清肾素活性(PRA)、血管紧张素Ⅱ(AngⅡ)、醛固酮(ALD)、去甲肾上腺素(NE)、肾上腺素(E)、肌酐(Cr)及左心室舒张内径(LVDD)、左心室射血分数(LVEF)差值,胸痛缓解率、生存率、再次住院率和主要不良心血管事件(非致死性心肌梗死、脑卒中)。结果PCI 组患者治疗6个月后血清 PRA、Ang Ⅱ、ALD、NE、E 及 LVEF 差值、再次住院率均明显低于 ODT 组,LVDD 差值、胸痛症状缓解率均明显高于 ODT 组(均P <0.05)。结论PCI 较 ODT 能够显著降低高龄不稳定性心绞痛患者心脏相关神经内分泌因子的水平,PCI 的治疗疗效明显优于单纯优化药物治疗。%ABSTRACT:Objective To investigate the clinical efficacy of percutaneous coronary intervention (PCI)for unstable angina in elderly patients.Methods A total of 118 elderly patients with unsta-ble angina were divided into two groups.Patients in PCI group(n=65)were given PCI and post-operative treatment with enteric-coated aspirin tablets and clopidogrel bisulfate.Patients in ODT group(n=53)were treated with enteric-coated aspirin tablets,clopidogrel bisulfate and optimal drug therapy(ODT).Serum renin activity,angiotensin Ⅱ (AngⅡ),aldosterone(ALD),norepi-nephrine(NE),epinephrine(E),creatinine(Cr),left ventricular diastolic inner diameter(LVDD) difference,left ventricular ejection fraction(LVEF)difference,chest pain remission rate,survival rate,readmission rate,and incidence of adverse

  4. Comparative Climate Responses of Anthropogenic Greenhouse Gases, All Major Aerosol Components, Black Carbon, and Methane, Accounting for the Evolution of the Aerosol Mixing State and of Clouds/Precipitation from Multiple Aerosol Size Distributions

    Science.gov (United States)

    Jacobson, M. Z.

    2005-12-01

    Several modeling studies to date have simulated the global climate response of anthropogenic greenhouse gases and bulk (non-size-resolved) sulfate or generic aerosol particles together, but no study has examined the climate response of greenhouse gases simultaneously with all major size- and composition resolved aerosol particle components. Such a study is important for improving our understanding of the effects of anthropogenic pollutants on climate. Here, the GATOR-GCMOM model is used to study the global climate response of (a) all major greenhouse gases and size-resolved aerosol components, (b) all major greenhouse gases alone, (c) fossil-fuel soot (black carbon, primary organic matter, sulfuric acid, bisulfate, sulfate), and (d) methane. Aerosol components treated in all simulations included water, black carbon, primary organic carbon, secondary organic carbon, sulfuric acid, bisulfate, sulfate, nitrate, chloride, ammonium, sodium, hydrogen ion, soil dust, and pollen/spores. Fossil-fuel soot (FFS) was emitted into its own size distribution. All other components, including biofuel and biomass soot, sea-spray, soil dust, etc., were emitted into a second distribution (MIX). The FFS distribution grew by condensation of secondary organic matter and sulfuric acid, hydration of water, and dissolution of nitric acid, ammonia, and hydrochloric acid. It self-coagulated and heterocoagulated with the MIX distribution, which also grew by condensation, hydration, and dissolution. Treatment of separate distributions for FFS allowed FFS to evolve from an external mixture to an internal mixture. In both distributions, black carbon was treated as a core component for optical calculations. Both aerosol distributions served as CCN during explicit size-resolved cloud formation. The resulting clouds grew by coagulation and condensation, coagulated with interstitial aerosol particles, and fell to the surface as rain and snow, carrying aerosol constituents with them. Thus, cloud

  5. Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    S. T. Martin

    2003-10-01

    Full Text Available The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US and once for lower side (LS of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m2  (g SO42−−1, which compare to US values of 0.030 and 13.9 m2 (g SO42−−1. Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (FL and FU, respectively, in W m2− are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of FL = −0.750, FU = −0.930, and

  6. Direct Conversion of Methane to Methanol under Mild Conditions over Cu-Zeolites and beyond.

    Science.gov (United States)

    Tomkins, Patrick; Ranocchiari, Marco; van Bokhoven, Jeroen A

    2017-02-21

    In the recent years methane has become increasingly abundant. However, transportation costs are high and methane recovered as side product is often flared rather than valorized. The chemical utilization of methane is highly challenging and currently mainly based on the cost-intensive production of synthesis gas and its conversion. Alternative routes have been discovered in academia, though high temperatures are mostly required. However, the direct conversion of methane to methanol is an exception. It can already be carried out at comparably low temperatures. It is challenging that methanol is more prone to oxidation than methane, which makes high selectivities at moderate conversions difficult to reach. Decades of research for the direct reaction of methane and oxygen did not yield a satisfactory solution for the direct partial oxidation toward methanol. When changing the oxidant from oxygen to hydrogen peroxide, high selectivities can be reached at rather low conversions, but the cost of hydrogen peroxide is comparably high. However, major advancements in the field were introduced by converting methane to a more stable methanol precursor. Most notable is the conversion of methane to methyl bisulfate in the presence of a platinum catalyst. The reaction is carried out in 102% sulfuric acid using SO3 as the oxidant. This allows for oxidation of the platinum catalyst and prevents the in situ hydrolysis of methyl bisulfate toward the less stable methanol. With a slightly different motif, the stepped conversion of methane to methanol over copper-zeolites was developed a decade ago. The copper-zeolite is first activated in oxygen at 450 °C, and then cooled to 200 °C and reacts with methane in the absence of oxygen, thus protecting a methanol precursor from overoxidation. Subsequently methanol can be extracted with water. Several active copper-zeolites were found, and the active sites were identified and discussed. For a long time, the process was almost unchanged

  7. Preparation and properties of P (AM-DMDAAC) CB composite hydrogel as profile control agent%复合水凝胶调剖剂 P(AM-DMDAAC)CB 的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    程绍玲; 黄春龙; 张雅佩; 吴振; 曲志慧

    2015-01-01

    In this work , a type of composite hydrogel as a profile control agent based on the acrylamide (AM) ,diallyl dimethyl ammonium chloride(DMDAAC) ,and calcium bentoniteand(CB) is prepared with free radical solution polymerization using ammonium persulfate/sodium bisulfate as a redox initiating pair , and N ,N′‐methylene‐bis‐acrylamide(MBA) as a crosslinker . The morphology and the crystal deformation are characterized by SEM and XRD , respectively . The effect of the reaction condition on the swelling capacity and compressive strength of the profile control agent is investigated . The optimum processing technology is obtained as follows :the mass ratio of AM to DMDAAC 9∶1 ,MBA dose 0.16% (the ratio of the total monomers mass , the same below ) , initiator dose (for ammonium persulfate , the mass ratio of ammonium persulfate to sodium bisulfate is 1∶1) 0.08% ,CB content 100% ,and reaction temperature 55℃ .Compared to clay‐free hydrogel P(AM‐DMDAAC) ,P(AM‐AMPS)/CB(CB addition amount 100% ) hydrogel exhibits a better performance :the cost is reduced by about 50% and the compressive strength is enhanced largely ,despite the swelling capacity decreases somewhat .%以丙烯酰胺(AM )、二甲基二烯丙基氯化铵(DMDAAC)为聚合单体,钙基膨润土(CB)为增韧剂, N ,N′‐亚甲基双丙烯酰胺(MBA )为交联剂,过硫酸铵和亚硫酸氢钠为引发剂,采用水溶液聚合法,合成了一种复合型水凝胶调剖剂P(AM‐DMDAAC )/CB .通过SEM和XRD表征了调剖剂的形貌和CB的晶型变化,探讨了反应条件对调剖剂的吸水倍率和压缩强度的影响.得到最佳制备条件为:AM与DMDAAC的质量比为9∶1, MBA用量为0.16%(占单体总质量的比例,下同), CB添加量为100%,引发剂用量(以过硫酸铵质量计,过硫酸铵和亚硫酸氢钠质量比为1∶1)为0.08%,反应温度为55℃.在最佳工艺条件下

  8. MBRidge: an accurate and cost-effective method for profiling DNA methylome at single-base resolution.

    Science.gov (United States)

    Cai, Wanshi; Mao, Fengbiao; Teng, Huajing; Cai, Tao; Zhao, Fangqing; Wu, Jinyu; Sun, Zhong Sheng

    2015-08-01

    Organisms and cells, in response to environmental influences or during development, undergo considerable changes in DNA methylation on a genome-wide scale, which are linked to a variety of biological processes. Using MethylC-seq to decipher DNA methylome at single-base resolution is prohibitively costly. In this study, we develop a novel approach, named MBRidge, to detect the methylation levels of repertoire CpGs, by innovatively introducing C-hydroxylmethylated adapters and bisulfate treatment into the MeDIP-seq protocol and employing ridge regression in data analysis. A systematic evaluation of DNA methylome in a human ovarian cell line T29 showed that MBRidge achieved high correlation (R > 0.90) with much less cost (∼10%) in comparison with MethylC-seq. We further applied MBRidge to profiling DNA methylome in T29H, an oncogenic counterpart of T29's. By comparing methylomes of T29H and T29, we identified 131790 differential methylation regions (DMRs), which are mainly enriched in carcinogenesis-related pathways. These are substantially different from 7567 DMRs that were obtained by RRBS and related with cell development or differentiation. The integrated analysis of DMRs in the promoter and expression of DMR-corresponding genes revealed that DNA methylation enforced reverse regulation of gene expression, depending on the distance from the proximal DMR to transcription starting sites in both mRNA and lncRNA. Taken together, our results demonstrate that MBRidge is an efficient and cost-effective method that can be widely applied to profiling DNA methylomes.

  9. Highly efficient generation of transgenic sheep by lentivirus accompanying the alteration of methylation status.

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    Chenxi Liu

    Full Text Available BACKGROUND: Low efficiency of gene transfer and silence of transgene expression are the critical factors hampering the development of transgenic livestock. Recently, transfer of recombinant lentivirus has been demonstrated to be an efficient transgene delivery method in various animals. However, the lentiviral transgenesis and the methylation status of transgene in sheep have not been well addressed. METHODOLOGY/PRINCIPLE FINDINGS: EGFP transgenic sheep were generated by injecting recombinant lentivirus into zygotes. Of the 13 lambs born, 8 carried the EGFP transgene, and its chromosomal integration was identified in all tested tissues. Western blotting showed that GFP was expressed in all transgenic founders and their various tissues. Analysis of CpG methylation status of CMV promoter by bisulfate sequencing unraveled remarkable variation of methylation levels in transgenic sheep. The average methylation levels ranged from 37.6% to 79.1% in the transgenic individuals and 34.7% to 83% in the tested tissues. Correlative analysis of methylation status with GFP expression revealed that the GFP expression level was inversely correlated with methylation density. The similar phenomenon was also observed in tested tissues. Transgene integration determined by Southern blotting presented multiple integrants ranging from 2 to 6 copies in the genome of transgenic sheep. CONCLUSIONS/SIGNIFICANCE: Injection of lentiviral transgene into zygotes could be a promising efficient gene delivery system to generate transgenic sheep and achieved widespread transgene expression. The promoter of integrants transferred by lentiviral vector was subjected to dramatic alteration of methylation status and the transgene expression level was inversely correlative with promoter methylation density. Our work illustrated for the first time that generation of transgenic sheep by injecting recombinant lentivirus into zygote could be an efficient tool to improve sheep performance by

  10. Altered DNA methylation patterns of the H19 differentially methylated region and the DAZL gene promoter are associated with defective human sperm.

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    Bo Li

    Full Text Available DNA methylation disturbance is associated with defective human sperm. However, oligozoospermia (OZ and asthenozoospermia (AZ usually present together, and the relationship between the single-phenotype defects in human sperm and DNA methylation is poorly understood. In this study, 20 infertile OZ patients and 20 infertile AZ patients were compared with 20 fertile normozoospermic men. Bisulfate-specific PCR was used to analyze DNA methylation of the H19-DMR and the DAZL promoter in these subjects. A similar DNA methylation pattern of the H19-DMR was detected in AZ and NZ(control, with only complete methylation and mild hypomethylation(0.05. However, the methylation pattern of severe hypomethylation (>50% unmethylated CpGs and complete unmethylation was only detected in 5 OZ patients, and the occurrence of these two methylation patterns was 8.54±10.86% and 9±6.06%, respectively. Loss of DNA methylation of the H19-DMR in the OZ patients was found to mainly occur in CTCF-binding site 6, with occurrence of 18.15±14.71%, which was much higher than that in patients with NZ (0.84±2.05% and AZ (0.58±1.77% (P20% methylated clones in the DAZL promoter only in infertile patients, there was no significant difference between the AZ and OZ patients in the proportion of moderately-to-severely hypermethylated clones (p>0.05. In all cases, global sperm genome methylation analyses, using LINE1 transposon as the indicator, showed that dysregulation of DNA methylation is specifically associated with the H19-DMR and DAZL promoter. Therefore, abnormal DNA methylation status of H19-DMR, especially at the CTCF-binding site 6, is closely associated with OZ. Abnormal DNA methylation of the DAZL promoter might represent an epigenetic marker of male infertility.

  11. Possible involvement of locus-specific methylation on expression regulation of leafy homologous gene (CiLFY during precocious trifoliate orange phase change process.

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    Jin-Zhi Zhang

    Full Text Available DNA methylation plays an essential role in regulating plant development. Here, we described an early flowering trifoliate orange (precocious trifoliate orange, Poncirus trifoliata L. Raf was treated with 5-azacytidine and displayed a number of phenotypic and developmental abnormalities. These observations suggested that DNA methylation might play an important role in regulating many developmental pathways including early flowering trait, and then the expression level of five key or integrated citrus flowering genes were analyzed. Our results showed that flowering locus T (CiFT relative expression level was increased with the increasing concentrations of 5-AzaC. However, leafy (CiLFY, APETELA1 (CiAP1, terminal flower1 (CiTFL1, and flowering locus C (CiFLC showed highest relative expression levels at 250 µΜ treatment, while decreased sharply at higher concentrations. In order to further confirm DNA methylation affects the expression of these genes, their full-length sequences were isolated by genome-walker method, and then was analyzed by using bioinformatics tools. However, only one locus-specific methylation site was observed in CiLFY sequence. Therefore, DNA methylation level of the CiLFY was investigated both at juvenile and adult stages of precocious trifoliate orange by bisulfate sequencing PCR; it has been shown that the level of DNA methylation was altered during phase change. In addition, spatial and temporal expression patterns of CiLFY promoter and a series of 5' deletions were investigated by driving the expression of a β-glucuronidase reporter gene in Arabidopsis. Exogenous GA3 treatment on transgenic Arabidopsis revealed that GA3 might be involved in the developmental regulation of CiLFY during flowering process of precocious trifoliate orange. These results provided insights into the molecular regulation of CiLFY gene expression, which would be helpful for studying citrus flowering.

  12. Epigenetic signature of panic disorder: a role of glutamate decarboxylase 1 (GAD1) DNA hypomethylation?

    Science.gov (United States)

    Domschke, Katharina; Tidow, Nicola; Schrempf, Marie; Schwarte, Kathrin; Klauke, Benedikt; Reif, Andreas; Kersting, Anette; Arolt, Volker; Zwanzger, Peter; Deckert, Jürgen

    2013-10-01

    Glutamate decarboxylases (GAD67/65; GAD1/GAD2) are crucially involved in gamma-aminobutyric acid (GABA) synthesis and thus were repeatedly suggested to play an important role in the pathogenesis of anxiety disorders. In the present study, DNA methylation patterns in the GAD1 and GAD2 promoter and GAD1 intron 2 regions were investigated for association with panic disorder, with particular attention to possible effects of environmental factors. Sixty-five patients with panic disorder (f=44, m=21) and 65 matched healthy controls were analyzed for DNA methylation status at 38 GAD1 promoter/intron2 and 10 GAD2 promoter CpG sites via direct sequencing of sodium bisulfate treated DNA extracted from blood cells. Recent positive and negative life events were ascertained. Patients and controls were genotyped for GAD1 rs3762556, rs3791878 and rs3762555, all of which are located in the analyzed promoter region. Patients with panic disorder exhibited significantly lower average GAD1 methylation than healthy controls (p<0.001), particularly at three CpG sites in the promoter as well as in intron 2. The occurrence of negative life events was correlated with relatively decreased average methylation mainly in the female subsample (p=0.01). GAD1 SNP rs3762555 conferred a significantly lower methylation at three GAD1 intron 2 CpG sites (p<0.001). No differential methylation was observed in the GAD2 gene. The present pilot data suggest a potentially compensatory role of GAD1 gene hypomethylation in panic disorder possibly mediating the influence of negative life events and depending on genetic variation. Future studies are warranted to replicate the present finding in independent samples, preferably in a longitudinal design.

  13. Hypermethylations of RASAL1 and KLOTHO is associated with renal dysfunction in a Chinese population environmentally exposed to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chen; Liang, Yihuai [School of Public Health, Fudan University, 130 DongAn Road, Shanghai 200032 (China); Key Laboratory of Public Health Safety, Ministry of Education, 130 DongAn Road, Shanghai 200032 (China); Lei, Lijian [Department of Epidemiology, School of Public Health, Shanxi Medical University, Shanxi (China); Zhu, Guoying; Chen, Xiao [Department of Bone Metabolism, Institute of Radiation Medicine, Fudan University, Shanghai (China); Jin, Taiyi, E-mail: tyjin@shmu.edu.cn [School of Public Health, Fudan University, 130 DongAn Road, Shanghai 200032 (China); Key Laboratory of Public Health Safety, Ministry of Education, 130 DongAn Road, Shanghai 200032 (China); Wu, Qing, E-mail: qingwu@fudan.edu.cn [School of Public Health, Fudan University, 130 DongAn Road, Shanghai 200032 (China); Key Laboratory of Public Health Safety, Ministry of Education, 130 DongAn Road, Shanghai 200032 (China)

    2013-08-15

    Exposure to cadmium (Cd) can affect both DNA methylation and renal function, but there are few examples of the association between epigenetic markers and Cd-induced kidney damage. It has been suggested that hypermethylation of the genes RASAL1 and KLOTHO is associated with renal fibrogenesis. To investigate whether hypermethylation of RASAL1 and KLOTHO in peripheral blood DNA can be associated with Cd exposure and/or Cd-induced renal dysfunction, the degrees of methylation of RASAL1 and KLOTHO in peripheral blood DNA from 81 residents in Cd-polluted and non-polluted areas were measured using bisulfate-PCR-pyrosequencing. Changes in blood cadmium (BCd), urinary cadmium (UCd), and kidney parameters were measured, and the glomerular filtration rate (eGFR) was estimated. The levels of BCd and UCd correlated positively with the levels of DNA methylation in RASAL1 and in KLOTHO. The more heavily exposed residents (BCd, 4.23–13.22 μg/L; UCd, 8.65–32.90 μg/g creatinine) exhibited obvious renal dysfunction. Notably, when Cd concentration in blood and urine was adjusted, the increased methylation level in RASAL1 was inversely correlated with eGFR (P < 0.01) but the relationship between hypermethylation of KLOTHO and eGFR was not statistically significant. The methylation of RASAL1 increased along with the increased abnormal prevalence of eGFR. Our findings suggest that Cd exposure can induce the hypermethylation of RASAL1 and KLOTHO. Hypermethylation of RASAL1 may be an indicator of the progress for chronic kidney disease. - Highlights: • A long term heavily Cd exposure induced renal dysfunction. • Cd exposure correlated positively with DNA methylation in RASAL1 and KLOTHO. • Hypermethylation of RASAL1 correlated with adjusted renal function indicators.

  14. Aged organic aerosol in the Eastern Mediterranean: the Finokalia aerosol measurement experiment-2008

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    L. Hildebrandt

    2010-01-01

    Full Text Available Aged organic aerosol (OA was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008, which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1, and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with time of day, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm−3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  15. Insect Cell Glycosylation and Its Impact on the Functionality of a Recombinant Intracrystalline Nacre Protein, AP24.

    Science.gov (United States)

    Chang, Eric P; Perovic, Iva; Rao, Ashit; Cölfen, Helmut; Evans, John Spencer

    2016-02-23

    The impacts of glycosylation on biomineralization protein function are largely unknown. This is certainly true for the mollusk shell, where glycosylated intracrystalline proteins such as AP24 (Haliotis rufescens) exist but their functions and the role of glycosylation remain elusive. To assess the effect of glycosylation on protein function, we expressed two recombinant variants of AP24: an unglycosylated bacteria-expressed version (rAP24N) and a glycosylated insect cell-expressed version (rAP24G). Our findings indicate that rAP24G is expressed as a single polypeptide containing variations in glycosylation that create microheterogeneity in rAP24G molecular masses. These post-translational modifications incorporate O- and N-glycans and anionic monosialylated and bisialylated, and monosulfated and bisulfated monosaccharides on the protein molecules. AFM and DLS experiments confirm that both rAP24N and rAP24G aggregate to form protein phases, with rAP24N exhibiting a higher degree of aggregation, compared to rAP24G. With regard to functionality, we observe that both recombinant proteins exhibit similar behavior within in vitro calcium carbonate mineralization assays and potentiometric titrations. However, rAP24G modifies crystal growth directions and is a stronger nucleation inhibitor, whereas rAP24N exhibits higher mineral phase stabilization and nanoparticle containment. We believe that the post-translational addition of anionic groups (via sialylation and sulfation), along with modifications to the protein surface topology, may explain the changes in glycosylated rAP24G aggregation and mineralization behavior, relative to rAP24N.

  16. Effect Observation on Lushi Runzao Decoction for Prim ary Sjogren's Syndrome for Three Months of Dry Eye Symptoms%路氏润燥汤对原发性干燥综合征3个月眼干症状的改善效果观察

    Institute of Scientific and Technical Information of China (English)

    郑丽萍; 孙玲; 崔长春

    2016-01-01

    Objective Discussion on the Lushi Runzao Decoction with primary Sjogren's syndrome improving effect of three months of dry eye symptoms. Methods71 patients with primary Sjogren's syndrome three months of dry eye symptoms in patients randomized to the treatment group (n = 36)in the application's Lushi Runzao Decoction ,control group (n = 35) using oral chloroquine bisulfate tablets for the treatment,compared to group 2 efficacy.ResultsAfter treatment of dry eye VAS score,the total effective rate were better than the control group(P<0.05).ConclusionLushi Runzao Decoction for three months of dry eye syndrome improving effect is certainly worth learning.%目的:探讨路氏润燥汤对原发性干燥综合征3个月眼干症状的改善效果。方法将71例原发性干燥综合征3个月眼干症状患者随机分组,治疗组(n=36)应用路氏润燥汤,对照组(n=35)口服硫酸氢氯喹片治疗,对比2组疗效。结果治疗组治疗后VAS眼干评分、治疗总有效率均优于对照组(P<0.05)。结论路氏润燥汤对原发性干燥综合征3个月眼干症状的改善效果肯定。

  17. Aged organic aerosol in the Eastern Mediterranean: the Finokalia Aerosol Measurement Experiment – 2008

    Directory of Open Access Journals (Sweden)

    L. Hildebrandt

    2010-05-01

    Full Text Available Aged organic aerosol (OA was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008, which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1, and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with source region, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm−3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  18. The evolutionary foundation of genomic imprinting in lower vertebrates

    Institute of Scientific and Technical Information of China (English)

    XIE BingHua; ZHANG Lei; ZHENG Kang; LUO Chen

    2009-01-01

    In mammals,genomic imprinting confers developmental asymmetry and complementation on the a-rental genomes and makes both parental genomes essential for complete development.Genomic im-printing is,therefore,the first regulatory step of genome-wide gene expression of embryogeneais and thought to be the epigenetic foundation of bisexual reproduction.However,how the genomic imprint-ing is originated,established and maintained during vertebrate evolution remains unknown.Because no endogenous imprinting gene has been identified in non-mammalian vertebrates,genomic imprinting is thought to be a unique evolutionary event of mammals.Here,in order to study the evolutionary origin of genomic imprinting in vertebrates,we examined whether parent-specific methylation occurred in the teleost homologue of mammalian imprinting gene during gametogenesis.Bisulfate sequencing analy-sis showed that,as mammalian Igf2 CpG island,goldfish Igf2 CpG island was a parental differentially methylated region (DMR) that was hypermethylated in sperm but unmethylated in eggs.Unlike mam-malian imprinting gene DMR,however,the parent-specific methylation pattern of goldfish Igf2 DMR was not maintained during embryogenesis,suggesting that the parent-specific methylation of goldfish Igf2 DMR might be a primitive genomic imprinting in the early period of vertebrate evolution.These results indicate that the evolutionary foundation of genomic imprinting exists in lower vertebrates and ge-nomic imprinting should not be considered as a unique evolutionary event of mammals.

  19. A Statistical and Theoretical Investigation of the Chemistry of the Formation of Atmospheric Particles in Beltsville, Maryland via Observations of Physical Properties

    Science.gov (United States)

    White, Rufus Tyrone

    Ion and trace gas measurements were performed with a newly developed Monitoring Instruments for Aerosols and Gases (MARGA) instrument. The MARGA gas measurements were successfully compared to similar instruments. A Laser Particle Counter (LPC) and Thermo Environmental Instrument Company (TECO) analyzers were used to obtain in-situ number density distribution and trace gas concentrations, respectively. Their ambient measurements showed that sulfuric acid and sulfate aerosols dominate the new particle formation events. In addition, statistical analytics show that the major determining factors that influenced the new particle formation (NPF) were wind speed and the amount of surface area available from preexisting aerosol particles. NPF occurred during the nights with low wind speed, and RH levels greater than 65%. The observed ratio ammonium to sulfate was 1:1, which suggest that sulfuric acid with ammonia partial neutralizes and ammonium bisulfate is the dominant species in the clusters. Other variables that influenced particle formation include emissions from nearby highway traffic and solar radiation. This study has also shown that the chemistry of new particle formation or production and subsequent growth are affected by three major components regional transport chemistry, local transformation chemistry, and rate of local pollution emissions. In addition, we find that the influence of these chemical processes can change based on diurnal cycles. This work may provide additional insights into the compounds and environmental conditions participating both in the initial formation and in subsequent growth of atmospheric aerosol particles. The results show the NPF is associated with Sulfur dioxide oxidation, condensation of volatile gases, and hygroscopic reactions, which are inhibited by the liquid aerosol surface area such that NPF competes with the liquid aerosol surface reactions. The principal components and correlation statistical analysis coefficients may

  20. Characterization of size-differentiated inorganic composition of aerosols in Mexico City

    Science.gov (United States)

    Moya, Mireya; Castro, Telma; Zepeda, Monica; Baez, Armando

    Size-differentiated atmospheric aerosol particles were collected during December 2000-October 2001 in Mexico City (19°N, 99°W) using a micro-orifice uniform deposit impactor. Sulfate and ammonium, which were correlated, were major features of the size distributions. The more predominant mode was at 0.32±0.1 μm, aerodynamic diameter. This peak of concentration is likely the result of condensation of secondary aerosol components from the gas phase. During part of the rainy season (April and June), a larger mode was found at 0.56±0.2 μm, aerodynamic diameter. This peak of concentration, identified as a droplet mode, is probably the result of aqueous-phase reactions (i.e., oxidation of sulfur dioxide in liquid droplets). During August, the peak of concentration was observed at both size ranges of the accumulation mode. Overall, ion balances were achieved with a small deficit of cations, except for the April and June samples, where a significant amount of excess sulfate was present as a result of moderate-high activity of the neighboring volcano Popocatepetl, as well as ambient conditions that favored production of sulfate (moderate-high relative humidity values). Based on the analysis of the ammonia/sulfate molar ratios, the ammonia concentrations were sufficient to fully neutralize sulfate concentrations, except for the April and June samples. During these months, ammonium bisulfate, letovicite and H 2SO 4(aq) (or a solution of the corresponding ions) were the dominant form of sulfate present in both fine and coarse modes. The acidic nature of these particles (with NH 3/H 2SO 4 molar ratio less than 2) is potentially important in assessing health effects of inhaled particles.

  1. Amine Reactivity with Nanoclusters of Sulfuric Acid and Ammonia

    Science.gov (United States)

    Johnston, M. V.; Bzdek, B. R.; DePalma, J.

    2011-12-01

    Alkyl amines have emerged as key species in new particle formation and growth. This interest is reinforced by ambient measurements of amines (e.g. Smith et al., 2010) and enhanced levels of nitrogen (e.g. Bzdek et al., 2011) during growth of newly formed particles. An important mechanism of amine uptake is aminium salt formation, either by substituting for ammonium ions that already exist in the particle or by opening new channels for salt formation that are not favorable with ammonia. This presentation will focus on recent experimental and computational work in our group to study amine uptake into charged nanoclusters of sulfuric acid and ammonia. In the experimental work, clusters are produced by electrospray of an ammonium sulfate solution and then drawn into a Fourier transform ion cyclotron resonance mass spectrometer where a specific cluster is isolated and exposed to amine vapor. We find that amine reactivity is dependent on the size, composition and charge of the isolated cluster. For small clusters of either polarity, all ammonium ions reside on the surface and amine substitution occurs with near unit reaction probability. As the cluster size increases, an ammonium ion can be encapsulated in the center of the cluster, which provides a steric hindrance to amine substitution. Negatively charged clusters are more likely to be acidic than positively charged clusters. For acidic clusters, incoming amine molecules first substitute for preexisting ammonium ions and then add to the cluster until a "neutralized" aminium bisulfate composition is reached. Computational studies of these clusters provide fundamental insight into the thermodynamics and kinetics of amine uptake.

  2. Bond energies and structures of ammonia-sulfuric acid positive cluster ions.

    Science.gov (United States)

    Froyd, Karl D; Lovejoy, Edward R

    2012-06-21

    New particle formation in the atmosphere is initiated by nucleation of gas-phase species. The small molecular clusters that act as seeds for new particles are stabilized by the incorporation of an ion. Ion-induced nucleation of molecular cluster ions containing sulfuric acid generates new particles in the background troposphere. The addition of a proton-accepting species to sulfuric acid cluster ions can further stabilize them and may promote nucleation under a wider range of conditions. To understand and accurately predict atmospheric nucleation, the stabilities of each molecular cluster within a chemical family must be known. We present the first comprehensive measurements of the ammonia-sulfuric acid positive ion cluster system NH(4)(+)(NH(3))(n)(H(2)SO(4))(s). Enthalpies and entropies of individual growth steps within this system were measured using either an ion flow reactor-mass spectrometer system under equilibrium conditions or by thermal decomposition of clusters in an ion trap mass spectrometer. Low level ab initio structural calculations provided inputs to a master equation model to determine bond energies from thermal decomposition measurements. Optimized ab initio structures for clusters up through n = 3, s = 3 are reported. Upon addition of ammonia and sulfuric acid pairs, internal proton transfer generates multiple NH(4)(+) and HSO(4)(-) ions within the clusters. These multiple-ion structures are up to 50 kcal mol(-1) more stable than corresponding isomers that retain neutral NH(3) and H(2)SO(4) species. The lowest energy n = s clusters are composed entirely of ions. The addition of acid-base pairs to the core NH(4)(+) ion generates nanocrystals that begin to resemble the ammonium bisulfate bulk crystal starting with the smallest n = s cluster, NH(4)(+)(NH(3))(1)(H(2)SO(4))(1). In the absence of water, this cluster ion system nucleates spontaneously for conditions that encompass most of the free troposphere.

  3. Nucleation and growth of crystals under cirrus and polar stratospheric cloud conditions

    Science.gov (United States)

    Hallett, John; Queen, Brian; Teets, Edward; Fahey, James

    1995-03-01

    Laboratory studies examine phase changes of hygroscopic substances which occur as aerosol in stratosphere and troposphere (sodium chloride, ammonium sulfate, ammonium bisulfate, nitric acid, sulfuric acid), under controlled conditions, in samples volume 1 to 10(exp -4) ml. Crystallization of salts from supersaturated solutions is examined by slowly evaporating a solution drop on a substrate, under controlled relative humidity, until self nucleation occurs; controlled nucleation of ice in a mm capillary U-tube gives a measured ice crystallization velocity at known supercooling. Two states of crystallization occur for regions where hydrates exist. It is inferred that all of the materials readily exist as supersaturated/supercooled solutions; the degree of metastability appears to be slightly enhanced by inclusion of aircraft produced soot. The crystallization velocity is taken as a measure of viscosity. Results suggest an approach to a glass transition at high molality, supersaturation and/or supercooling within the range of atmospheric interest. It is hypothesized that surface reactions occur more readily on solidified particles - either crystalline or glass, whereas volume reactions are more important on droplets with sufficiently low viscosity and volume diffusivity. Implications are examined for optical properties of such particles in the atmosphere. In a separate experiment, crystal growth was examined in a modified thermal vapor diffusion chamber over the range of cirrus temperature (-30 to -70 C) and under controlled supersaturation and air pressure. The crystals grew at a velocity of 1-2 microns/s, thickness 60-70 micron, in the form of thin column crystals. Design criteria are given for a system to investigate particle growth down to -100 C, (PSC temperatures) where nitric acid particles can be grown under similar control and in the form of hydrate crystals.

  4. Heterogeneous Uptake of Gaseous N2O5 by Sulfate Aerosols

    Science.gov (United States)

    Leu, M.; Kane, S. M.; Caloz, F.

    2001-12-01

    The heterogeneous uptake of gaseous N2O5 by ammonium sulfate [(NH4)2SO4], ammonium bisulfate [NH4HSO4], and sulfuric acid [H2SO4] aerosols as a function of relative humidity has been investigated at room temperature and atmospheric pressure. Ammonium-containing aerosols were generated by a constant output atomizer and conditioned by passing through a diffusion dryer. Sulfuric acid aerosols were produced by the homogeneous reaction of SO3 and H2O in a borosilicate vessel. Addition of a dry or wet N2 flow controlled the relative humidity (RH) of these aerosol flows. Using a chemical ionization mass spectrometer (CIMS) for N2O5 concentration monitoring and a scanning mobility particle spectrometer (SMPS) for aerosol characterization, reaction probabilities (g) in the range of 0.001 to 0.1 for the uptake of N2O5 were determined as a function of RH. The results are expressed as follows: gamma[(NH4)2SO4] = 2.79 x 10-4 + 1.30 x 10-4 x (RH) -3.43 x 10-6 x (RH)2 + 7.52 x 10-8 x (RH)3, gamma[NH4HSO4] = 2.07 x 10-3 - 1.48 x 10-4 x (RH) + 8.26 x 10-6 x (RH)2, and gamma[H2SO4] = 0.052 - 2.79 x 10-4 x (RH) . We suggest that the water content and phase in the ammonium-containing aerosols control the reactivity of N2O5 while liquid-phase ionic reactions primarily dominate the uptake in sulfuric acid aerosols.

  5. Raman Spectra and Nucleation Rates of Sulfuric Acid and Ammonium Sulfate Aerosols Supercooled with Respect to Ice

    Science.gov (United States)

    Knopf, D. A.; Koop, T.; Weers, U. G.; Krieger, U. K.; Peter, T.

    2001-12-01

    Sulfuric acid and ammonium sulfate aerosol particles can serve as ice condensation nuclei for the formation of upper tropospheric cirrus clouds. These clouds influence the global radiation budget by scattering of short wavelength (solar) radiation as well as by absorbing long wavelength (terrestrial) radiation. Knowledge of the thermodynamics and the nucleation rates of aerosols is fundamental for the understanding of formation processes of cirrus clouds. Here, we present a new investigation tool to observe phase transitions of aerosols supercooled with respect to ice. Confocal Raman microscopy is used to determine the phase changes and the morphology of the particles. Raman spectroscopy is employed to distinguish and to characterize the different phases inside the frozen particles. Single droplets with a diameter of typically 20-120 μ m are deposited on a hydrophobically coated Herasil-plate that is covered by a spacer and another plate. Since the gas phase volume of the cell is small compared to the liquid droplet volume the composition of the droplets remains fixed during temperature changes. The temperature of the droplets can be varied between 150-350~K. We present the first Raman spectra of aqueous H2SO4/H2O and (NH4)2SO4/H2O droplets for several concentrations and temperatures to the homogeneous ice nucleation limits. The analysis of the speciation of the components inside the droplets (e.g. sulfate vs. bisulfate ions) is compared to results from thermodynamic models. Evaluation of the freezing data gives upper limits for ice nucleation rates of droplets as a function of sulfuric acid or ammonium sulfate concentration.

  6. Comparative potency of inhaled acidic sulfates: speciation and the role of hydrogen ion.

    Science.gov (United States)

    Schlesinger, R B; Chen, L C; Finkelstein, I; Zelikoff, J T

    1990-08-01

    Inhaled acidic sulfate aerosols affect various aspects of lung function, presumably by delivery of hydrogen ion (H+) to target sites. Recent evidence suggests that the relationship between response and H+ content of the exposure atmosphere may depend upon the specific sulfate species with which the H+ is associated. This study examined comparatively the effects of exposure to the two main ambient acidic sulfates, sulfuric acid (H2SO4) and ammonium bisulfate (NH4HSO4), using the phagocytic activity of alveolar macrophages as the endpoint. Rabbits were exposed to 250-2000 micrograms/m3 H2SO4 (as SO4(-2)) and 500-4000 micrograms/m3 NH4HSO4 (as SO4(-2)) for 1 hr/day for 5 days; bronchopulmonary lavage was then performed for recovery of free lung cells. Phagocytosis, measured by uptake of opsonized latex spheres in vitro, was altered by exposure to H2SO4 at concentrations greater than or equal to 500 micrograms/m3 and to NH4HSO4 at greater than or equal to 2000 micrograms/m3. Assessment of results in terms of the calculated hydrogen ion concentration in the exposure atmosphere showed that identical levels of H+ produced different degrees of response depending upon whether exposure was to H2SO4 or NH4HSO4. On the other hand, macrophages incubated in acidic environments in vitro responded similarly regardless of whether H2SO4 or NH4HSO4 was used to adjust the pH. Possible reasons for the difference in response observed in vivo and in vitro are discussed. Speciation of ambient acidic sulfate aerosols may be needed in atmospheric monitoring so as to assess the presence of H+ posing the greatest biologic hazard following inhalation exposure.

  7. Aerosol size distribution modeling with the Community Multiscale Air Quality modeling system in the Pacific Northwest: 2. Parameterizations for ternary nucleation and nucleation mode processes

    Science.gov (United States)

    Elleman, Robert A.; Covert, David S.

    2009-06-01

    In order to test Community Multiscale Air Quality (CMAQ) model performance for ultrafine particle concentrations in the Pacific Northwest, CMAQ v4.4 was modified for ternary NH3-H2SO4-H2O nucleation and for atmospheric processing of ultrafine particles. Sulfuric acid from sulfur dioxide oxidation is iteratively partitioned into gaseous sulfuric acid, newly condensed aerosol sulfate, and aerosol sulfuric acid contained in new 1 nm particles. Freshly nucleated particles are either coagulated to larger particles or grown by sulfuric acid condensation to 10 nm at which point they are included in CMAQ's existing Aitken mode. Multiple nucleation parameterizations were implemented into CMAQ, and one other was investigated in a sensitivity analysis. For a case study in the Pacific Northwest where aerosol number concentration and size distributions were measured, standard binary nucleation in CMAQ produces nearly no particles for this case study. Ternary nucleation can produce millions of 1 nm particles per cm3, but few of these particles survive coagulation loss and grow to 10 nm and into the Aitken mode. There are occasions when the additions to CMAQ increase the number of particles to within an order of magnitude of observations, but it is more common for number concentrations to remain underpredicted by, on average, one order of magnitude. Significant particle nucleation in CMAQ successfully produces a distinct Aitken and accumulation mode and an Aitken mode that is more prominent than the accumulation mode, although errors in the size distribution remain. A more recent ternary nucleation scheme including ammonium bisulfate clusters does not nucleate an appreciable number of particles.

  8. XPS spectra and electronic structure of Group IA sulfates

    Energy Technology Data Exchange (ETDEWEB)

    Wahlqvist, M. [Department of Chemistry, Inorganic Chemistry, Umea University, S-901 87 Umea (Sweden); Shchukarev, A. [Department of Chemistry, Inorganic Chemistry, Umea University, S-901 87 Umea (Sweden)], E-mail: andrei.shchukarev@chem.umu.se

    2007-05-15

    The results of systematic XPS measurements of Group IA (H, Li, Na, K, Rb and Cs) sulfates together with NaHSO{sub 4}, KHSO{sub 4} and (NH{sub 4}){sub 2}SO{sub 4} are presented. The experiments on the alkali metal salts were preformed on ground powders at both liquid nitrogen and room temperatures; concentrated sulfuric acid was measured as a fast-frozen liquid drop. Spectra from grounded and floated samples were compared, and no significant difference relating to charging effects was observed. The influence of grinding on surface chemistry of the powders is described. Such a mechanical activation produces mainly monohydrates on the surface of all sulfates. In the case of Na{sub 2}SO{sub 4}, an additional NaHSO{sub 4} surface phase seems to form that is not stable in vacuum even at liquid nitrogen temperatures. It was found that the binding energies (O 1s and S 2p) of sulfate ion decrease down the group. The shifts are discussed and related to ionicity of the metal-sulfate bond. The structure of XPS valence band spectra is in good agreement with cluster calculations of SO{sub 4}{sup 2-} and HSO{sub 4}{sup -} [A.A. Audi, P.M.A. Sherwood, Surf. Interface Anal. 29 (2000) 265]. While the energies of bisulfate bands are not influenced by the cation (H{sup +}, Na{sup +} or K{sup +}), the sulfate ones experience an increase in bond ionicity and demonstrate the same binding energy shifts as the core levels.

  9. Aerosol Particles From Tropical Cirrus Clouds in the Lower Stratosphere

    Science.gov (United States)

    Kojima, T.; Buseck, P. R.; Wilson, J. C.; Reeves, J. M.

    2002-12-01

    Aerosol samples were collected from convective systems and cirrus layers over Florida during the July 2002 CRYSTAL-FACE Mission. Particles between 0.02 and 700 \\micron were deposited directly onto TEM grids. Here we report preliminary results of the TEM study of particles collected near and above the tropopause. Most particles are sulfate droplets that range from 0.8 to 5 \\micron in diameter on the TEM grids. All have a characteristic appearance that consists of a main central particle (0.3 -1 \\micron) surrounded by many smaller satellite droplets. Their appearance suggests that the droplets were sulfuric acid partially neutralized with ammonium at the time of collection, with ammonium sulfate and bisulfate constituting the central particles (Bigg, 1975, 1980). The degree of ammoniation in individual droplets, which is indicated by the size of central particles relative to satellite ring diameter, is fairly uniform. The ratio of central particle diameter to satellite ring diameter is generally around 0.3. Such ammoniated droplets with solid cores may be more efficient in nucleating cirrus than pure sulfuric acid droplets (Tabazadeh and Toon, 1998). Ammonium sulfate particles without satellites commonly coexist with the acid droplets. Minor particles consist of C-rich amorphous material, silicates, Na- and K-chlorides and sulfates, and Cr- and Ti-oxides. Some were coated with sulfate. Many of the C-rich particles contain significant amount of K, S, and O with lesser N. All silicate particles are flakes of clay minerals that have pseudohexagonal structures. They would work as effective ice nuclei (Pruppacher and Klett, 1997).

  10. Particle Nucleation and Growth During the NIFTy Experiment

    Science.gov (United States)

    Barthelmie, R. J.; Pryor, S. C.; Spaulding, A. M.; Rossner, A.; Crimmins, B.; Hopke, P. K.; Mauldin, L.; Jobson, T.; Petaja, T.

    2008-12-01

    The measurements presented herein are being collected in order to assess the frequency and characteristics of nucleation events and high ultra-fine particle concentrations in this rural (but regionally polluted) setting, including the chemical composition of the ultra-fine particles, the principal mechanisms of nucleation, limitations on nucleation and growth and the ultimate fate of the resulting ultra-fine particles. We present a year of data from continuous measurements of particle size distributions (6 to 400 nm) at three- levels above and within a deciduous forest in southern Indiana (in the Ohio River Valley). These data are collected using two SMPS and one FMPS, and are supplemented with data concerning the spatial extent and the composition of ultra-fine particles using samples collected during May 2008 as part of the Nucleation In ForesTs (NIFTY) campaign. The long-term measurements indicate evidence of class A nucleation events on approximately 1 day in 5, and lesser magnitude or less well defined events on another 15% of days. These data indicate nucleation is most frequently observed in spring, but occurs in all seasons and subsequent growth is more rapid during leaf-on. During the NIFTY field experiment we enhanced the ongoing data collection at the forest site to include sulfuric acid, ammonia and VOC concentrations, and particle composition using two MOUDI-nano-MOUDI combinations. Preliminary analyses of these data indicate that the sub-32 nm diameter particles are almost completely ammonium-sulfate or ammonium-bisulfate and associated water but there is evidence that continued growth is aided by the addition of condensable organics. We further instrumented two additional sites - one directly south of the forest in a relatively rural setting, and one to the north in the city of Indianapolis. Results from these sites indicate strong evidence that the events are regional but the sites differ in terms of the magnitude of the events and the relative

  11. Structure and energetics of nanometer size clusters of sulfuric acid with ammonia and dimethylamine.

    Science.gov (United States)

    DePalma, Joseph W; Bzdek, Bryan R; Doren, Douglas J; Johnston, Murray V

    2012-01-26

    The structures of positively and negatively charged clusters of sulfuric acid with ammonia and/or dimethylamine ((CH(3))(2)NH or DMA) are investigated using a combination of Monte Carlo configuration sampling, semiempirical calculations, and density functional theory (DFT) calculations. Positively charged clusters of the formula [(NH(4)(+))(x)(HSO(4)(-))(y)](+), where x = y + 1, are studied for 1 ≤ y ≤ 10. These clusters exhibit strong cation-anion interactions, with no contribution to the hydrogen-bonding network from the bisulfate ion protons. A similar hydrogen-bonding network is found for the [(DMAH(+))(5)(HSO(4)(-))(4)](-) cluster. Negatively charged clusters derived from the reaction of DMA with [(H(2)SO(4))(3)(NH(4)(+))(HSO(4)(-))(2)](-) are also studied, up to the fully reacted cluster [(DMAH(+))(4)(HSO(4)(-))(5)](-). These clusters exhibit anion-anion and ion-molecule interactions in addition to cation-anion interactions. While the hydrogen-bonding network is extensive for both positively and negatively charged clusters, the binding energies of ions and molecules in these clusters are determined mostly by electrostatic interactions. The thermodynamics of amine substitution is explored and compared to experimental thermodynamic and kinetic data. Ammonia binds more strongly than DMA to sulfuric acid due to its greater participation in hydrogen bonding and its ability to form a more compact structure that increases electrostatic attraction between oppositely charged ions. However, the greater gas-phase basicity of DMA is sufficient to overcome the stronger binding of ammonia, making substitution of DMA for ammonia thermodynamically favorable. For small clusters of both polarities, substitutions of surface ammonium ions are facile. As the cluster size increases, an ammonium ion becomes encapsulated in the center of the cluster, making it inaccessible to substitution.

  12. Atmospheric concentrations of ammonia and ammonium at an agricultural site in the southeast United States

    Science.gov (United States)

    Robarge, Wayne P.; Walker, John T.; McCulloch, Ronald B.; Murray, George

    In this study, we present ˜1 yr (October 1998-September 1999) of 12-hour mean ammonia (NH 3), ammonium (NH 4+), hydrochloric acid (HCl), chloride (Cl -), nitrate (NO 3-), nitric acid (HNO 3), nitrous acid (HONO), sulfate (SO 42-), and sulfur dioxide (SO 2) concentrations measured at an agricultural site in North Carolina's Coastal Plain region. Mean gas concentrations were 0.46, 1.21, 0.54, 5.55, and 4.15 μg m -3 for HCl, HNO 3, HONO, NH 3, and SO 2, respectively. Mean aerosol concentrations were 1.44, 1.23, 0.08, and 3.37 μg m -3 for NH 4+, NO 3-, Cl -, and SO 42-, respectively. Ammonia, NH 4+, HNO 3, and SO 42- exhibit higher concentrations during the summer, while higher SO 2 concentrations occur during winter. A meteorology-based multivariate regression model using temperature, wind speed, and wind direction explains 76% of the variation in 12-hour mean NH 3 concentrations ( n=601). Ammonia concentration increases exponentially with temperature, which explains the majority of variation (54%) in 12-hour mean NH 3 concentrations. Dependence of NH 3 concentration on wind direction suggests a local source influence. Ammonia accounts for >70% of NH x (NH x=NH 3+NH 4+) during all seasons. Ammonium nitrate and sulfate aerosol formation does not appear to be NH 3 limited. Sulfate is primarily associated ammonium sulfate, rather than bisulfate, except during the winter when the ratio of NO 3--NH 4+ is ˜0.66. The annual average NO 3--NH 4+ ratio is ˜0.25.

  13. Microwave-assisted Heating Synthesis of Vanillin Propylene Glycol Acetal Catalyzed by NaHSO4%微波促进硫酸氢钠催化合成香兰素1.2-丙二醇缩醛

    Institute of Scientific and Technical Information of China (English)

    吴文陵; 林明穗; 王仁章; 吴泽民; 叶欣

    2012-01-01

    在微波辐射条件下,香兰索与1.2-丙二醇在硫酸氢钠的催化下.合成了香兰索丙二醇缩醛。探讨了原料配比、催化剂用量、微波辐射功率及时问等因素对反应的影响。适宜反应条件为:n(1,2-丙二醇):n(香兰素)=2.2,20ml环已烷作带水剂,3.0g/mol硫酸氢钠作催化剂,辐射功率500w,辐射时间10min,香兰素转化率可达68.2%。结果表明,微波辐射与催化荆联用,可大大缩短反应时间,反应过程环保简便。%The vanillin 1, 2 - propylene glycol acetal was synthesized by the reaction of vanillin and 1, 2-propylene glycol using sodium bisulfate as catalyst under microwave irradiation. Factors influencing the reaction, such as different mole ratio of materials, catalyst amounts, microwave irradiation power and time, were discussed. The optimal synthetic technology was obtained as follows: n (1, 2 - propylene glycol) : n (vanillin) = 2.2, irradiation power 500 W, irradiation time 10 rain, NariS04 3.0 g/mol ( based on the amount of vanillin), 20ml cyclohexane to give in 68.2% yield.

  14. Prasugrel suppresses development of lithium-induced nephrogenic diabetes insipidus in mice.

    Science.gov (United States)

    Zhang, Yue; Peti-Peterdi, János; Brandes, Anna U; Riquier-Brison, Anne; Carlson, Noel G; Müller, Christa E; Ecelbarger, Carolyn M; Kishore, Bellamkonda K

    2017-02-23

    Previously, we localized ADP-activated P2Y12 receptor (R) in rodent kidney and showed that its blockade by clopidogrel bisulfate (CLPD) attenuates lithium (Li)-induced nephrogenic diabetes insipidus (NDI). Here, we evaluated the effect of prasugrel (PRSG) administration on Li-induced NDI in mice. Both CLPD and PRSG belong to the thienopyridine class of ADP receptor antagonists. Groups of age-matched adult male B6D2 mice (N = 5/group) were fed either regular rodent chow (CNT), or with added LiCl (40 mmol/kg chow) or PRSG in drinking water (10 mg/kg bw/day) or a combination of LiCl and PRSG for 14 days and then euthanized. Water intake and urine output were determined and blood and kidney tissues were collected and analyzed. PRSG administration completely suppressed Li-induced polydipsia and polyuria and significantly prevented Li-induced decreases in AQP2 protein abundance in renal cortex and medulla. However, PRSG either alone or in combination with Li did not have a significant effect on the protein abundances of NKCC2 or NCC in the cortex and/or medulla. Immunofluorescence microscopy revealed that PRSG administration prevented Li-induced alterations in cellular disposition of AQP2 protein in medullary collecting ducts. Serum Li, Na, and osmolality were not affected by the administration of PRSG. Similar to CLPD, PRSG administration had no effect on Li-induced increase in urinary Na excretion. However, unlike CLPD, PRSG did not augment Li-induced increase in urinary arginine vasopressin (AVP) excretion. Taken together, these data suggest that the pharmacological inhibition of P2Y12-R by the thienopyridine group of drugs may potentially offer therapeutic benefits in Li-induced NDI.

  15. P2Y12 Receptor Localizes in the Renal Collecting Duct and Its Blockade Augments Arginine Vasopressin Action and Alleviates Nephrogenic Diabetes Insipidus.

    Science.gov (United States)

    Zhang, Yue; Peti-Peterdi, Janos; Müller, Christa E; Carlson, Noel G; Baqi, Younis; Strasburg, David L; Heiney, Kristina M; Villanueva, Karie; Kohan, Donald E; Kishore, Bellamkonda K

    2015-12-01

    P2Y12 receptor (P2Y12-R) signaling is mediated through Gi, ultimately reducing cellular cAMP levels. Because cAMP is a central modulator of arginine vasopressin (AVP)-induced water transport in the renal collecting duct (CD), we hypothesized that if expressed in the CD, P2Y12-R may play a role in renal handling of water in health and in nephrogenic diabetes insipidus. We found P2Y12-R mRNA expression in rat kidney, and immunolocalized its protein and aquaporin-2 (AQP2) in CD principal cells. Administration of clopidogrel bisulfate, an irreversible inhibitor of P2Y12-R, significantly increased urine concentration and AQP2 protein in the kidneys of Sprague-Dawley rats. Notably, clopidogrel did not alter urine concentration in Brattleboro rats that lack AVP. Clopidogrel administration also significantly ameliorated lithium-induced polyuria, improved urine concentrating ability and AQP2 protein abundance, and reversed the lithium-induced increase in free-water excretion, without decreasing blood or kidney tissue lithium levels. Clopidogrel administration also augmented the lithium-induced increase in urinary AVP excretion and suppressed the lithium-induced increase in urinary nitrates/nitrites (nitric oxide production) and 8-isoprostane (oxidative stress). Furthermore, selective blockade of P2Y12-R by the reversible antagonist PSB-0739 in primary cultures of rat inner medullary CD cells potentiated the expression of AQP2 and AQP3 mRNA, and cAMP production induced by dDAVP (desmopressin). In conclusion, pharmacologic blockade of renal P2Y12-R increases urinary concentrating ability by augmenting the effect of AVP on the kidney and ameliorates lithium-induced NDI by potentiating the action of AVP on the CD. This strategy may offer a novel and effective therapy for lithium-induced NDI.

  16. Clopidogrel attenuates lithium-induced alterations in renal water and sodium channels/transporters in mice.

    Science.gov (United States)

    Zhang, Yue; Peti-Peterdi, János; Heiney, Kristina M; Riquier-Brison, Anne; Carlson, Noel G; Müller, Christa E; Ecelbarger, Carolyn M; Kishore, Bellamkonda K

    2015-12-01

    Lithium (Li) administration causes deranged expression and function of renal aquaporins and sodium channels/transporters resulting in nephrogenic diabetes insipidus (NDI). Extracellular nucleotides (ATP/ADP/UTP), via P2 receptors, regulate these transport functions. We tested whether clopidogrel bisulfate (CLPD), an antagonist of ADP-activated P2Y(12) receptor, would affect Li-induced alterations in renal aquaporins and sodium channels/transporters. Adult mice were treated for 14 days with CLPD and/or Li and euthanized. Urine and kidneys were collected for analysis. When administered with Li, CLPD ameliorated polyuria, attenuated the rise in urine prostaglandin E2 (PGE2), and resulted in significantly higher urinary arginine vasopressin (AVP) and aldosterone levels as compared to Li treatment alone. However, urine sodium excretion remained elevated. Semi-quantitative immunoblotting revealed that CLPD alone increased renal aquaporin 2 (AQP2), Na-K-2Cl cotransporter (NKCC2), Na-Cl cotransporter (NCC), and the subunits of the epithelial Na channel (ENaC) in medulla by 25-130 %. When combined with Li, CLPD prevented downregulation of AQP2, Na-K-ATPase, and NKCC2 but was less effective against downregulation of cortical α- or γ-ENaC (70 kDa band). Thus, CLPD primarily attenuated Li-induced downregulation of proteins involved in water conservation (AVP-sensitive), with modest effects on aldosterone-sensitive proteins potentially explaining sustained natriuresis. Confocal immunofluorescence microscopy revealed strong labeling for P2Y(12)-R in proximal tubule brush border and blood vessels in the cortex and less intense labeling in medullary thick ascending limb and the collecting ducts. Therefore, there is the potential for CLPD to be directly acting at the tubule sites to mediate these effects. In conclusion, P2Y(12)-R may represent a novel therapeutic target for Li-induced NDI.

  17. Targeting Renal Purinergic Signalling for the Treatment of Lithium-induced Nephrogenic Diabetes Insipidus

    Science.gov (United States)

    Kishore, B. K.; Carlson, N. G.; Ecelbarger, C. M.; Kohan, D. E.; Müller, C. E.; Nelson, R. D.; Peti-Peterdi, J.; Zhang, Y.

    2015-01-01

    Lithium still retains its critical position in the treatment of bipolar disorder by virtue of its ability to prevent suicidal tendencies. However, chronic use of lithium is often limited by the development nephrogenic diabetes insipidus (NDI), a debilitating condition. Lithium-induced NDI is due to resistance of the kidney to arginine vasopressin (AVP), leading to polyuria, natriuresis and kaliuresis. Purinergic signalling mediated by extracellular nucleotides (ATP/UTP), acting via P2Y receptors, opposes the action of AVP on renal collecting duct (CD) by decreasing the cellular cAMP and thus AQP2 protein levels. Taking a cue from this phenomenon, we discovered the potential involvement of ATP/UTP-activated P2Y2 receptor in lithium-induced NDI in rats, and showed that P2Y2 receptor knockout mice are significantly resistant to Li-induced polyuria, natriuresis and kaliuresis. Extension of these studies revealed that ADP-activated P2Y12 receptor is expressed in the kidney, and its irreversible blockade by the administration of clopidogrel bisulfate (Plavix®) ameliorates Li-induced NDI in rodents. Parallel in vitro studies showed that P2Y12 receptor blockade by the reversible antagonist PSB-0739 sensitizes CD to the action of AVP. Thus, our studies unraveled the potential beneficial effects of targeting P2Y2 or P2Y12 receptors to counter AVP resistance in lithium-induced NDI. If established in further studies, our findings may pave the way for the development of better and safer methods for the treatment of NDI by bringing a paradigm shift in the approach from the current therapies that predominantly counter the anti-AVP effects to those that enhance the sensitivity of the kidney to AVP action. PMID:25877068

  18. Evaluating genome-wide DNA methylation changes in mice by Methylation Specific Digital Karyotyping

    Directory of Open Access Journals (Sweden)

    Maruoka Shuichiro

    2008-12-01

    Full Text Available Abstract Background The study of genome-wide DNA methylation changes has become more accessible with the development of various array-based technologies though when studying species other than human the choice of applications are limited and not always within reach. In this study, we adapted and tested the applicability of Methylation Specific Digital Karyotyping (MSDK, a non-array based method, for the prospective analysis of epigenetic changes after perinatal nutritional modifications in a mouse model of allergic airway disease. MSDK is a sequenced based method that allows a comprehensive and unbiased methylation profiling. The method generates 21 base pairs long sequence tags derived from specific locations in the genome. The resulting tag frequencies determine in a quantitative manner the methylation level of the corresponding loci. Results Genomic DNA from whole lung was isolated and subjected to MSDK analysis using the methylation-sensitive enzyme Not I as the mapping enzyme and Nla III as the fragmenting enzyme. In a pair wise comparison of the generated mouse MSDK libraries we identified 158 loci that are significantly differentially methylated (P-value = 0.05 after perinatal dietary changes in our mouse model. Quantitative methylation specific PCR and sequence analysis of bisulfate modified genomic DNA confirmed changes in methylation at specific loci. Differences in genomic MSDK tag counts for a selected set of genes, correlated well with changes in transcription levels as measured by real-time PCR. Furthermore serial analysis of gene expression profiling demonstrated a dramatic difference in expressed transcripts in mice exposed to perinatal nutritional changes. Conclusion The genome-wide methylation survey applied in this study allowed for an unbiased methylation profiling revealing subtle changes in DNA methylation in mice maternally exposed to dietary changes in methyl-donor content. The MSDK method is applicable for mouse models

  19. 固体酸催化蓖麻油制备生物柴油%Preparation of biodiesel from castor seed oil using solid acid as a catalyst

    Institute of Scientific and Technical Information of China (English)

    靳福全; 牛宇岚; 李晓红

    2011-01-01

    以一水硫酸氢钠固体酸为催化剂,对蓖麻油酯交换制备生物柴油进行了研究.在反应温度为75℃条件下,考察了醇油摩尔比、催化剂用量(占油质量)及反应时间对酯交换反应的影响.在反应温度为75℃、醇油摩尔比为9:1、催化剂用量为4%、反应时间为8 h的优化工艺条件下,平均甘油收率达93%,产物中甲酯总含量为95.20%.甲酯和甘油静置分层快,后处理简单,对环境无污染.%The transesterification of castor seed oil to produce biodiesel catalyzed by solid acid sodium bisulfate monohydrate was studied. At the temperature of 75 ℃, effects of molar ratio of methanol to oil, catalyst dosage ( mass ratio of catalyst to oil) and reaction time on the transesterification were investigated. Under the optimal conditions of reaction temperature 75 ℃, molar ratio of methanol to oil 9: 1, catalyst dosage 4% and reaction time 8 h, the average yield of glycerine arrived 93% . The products were analyzed by GC - MS and the mass fraction of methyl ester was 95.20%. The methyl ester and the glycerine were easily separated, and the method had no pollution to the environment.

  20. Identification of new differentially methylated genes that have potential functional consequences in prostate cancer.

    Directory of Open Access Journals (Sweden)

    Jin W Kim

    Full Text Available Many differentially methylated genes have been identified in prostate cancer (PCa, primarily using candidate gene-based assays. Recently, several global DNA methylation profiles have been reported in PCa, however, each of these has weaknesses in terms of ability to observe global DNA methylation alterations in PCa. We hypothesize that there remains unidentified aberrant DNA methylation in PCa, which may be identified using higher resolution assay methods. We used the newly developed Illumina HumanMethylation450 BeadChip in PCa (n = 19 and adjacent normal tissues (n = 4 and combined these with gene expression data for identifying new DNA methylation that may have functional consequences in PCa development and progression. We also confirmed our methylation results in an independent data set. Two aberrant DNA methylation genes were validated among an additional 56 PCa samples and 55 adjacent normal tissues. A total 28,735 CpG sites showed significant differences in DNA methylation (FDR adjusted P<0.05, defined as a mean methylation difference of at least 20% between PCa and normal samples. Furthermore, a total of 122 genes had more than one differentially methylated CpG site in their promoter region and a gene expression pattern that was inverse to the direction of change in DNA methylation (e.g. decreased expression with increased methylation, and vice-versa. Aberrant DNA methylation of two genes, AOX1 and SPON2, were confirmed via bisulfate sequencing, with most of the respective CpG sites showing significant differences between tumor samples and normal tissues. The AOX1 promoter region showed hypermethylation in 92.6% of 54 tested PCa samples in contrast to only three out of 53 tested normal tissues. This study used a new BeadChip combined with gene expression data in PCa to identify novel differentially methylated CpG sites located within genes. The newly identified differentially methylated genes may be used as biomarkers for PCa diagnosis.

  1. Bridge-bonded formate: active intermediate or spectator species in formic acid oxidation on a Pt film electrode?

    Science.gov (United States)

    Chen, Y-X; Heinen, M; Jusys, Z; Behm, R J

    2006-12-01

    We present and discuss the results of an in situ IR study on the mechanism and kinetics of formic acid oxidation on a Pt film/Si electrode, performed in an attenuated total reflection (ATR) flow cell configuration under controlled mass transport conditions, which specifically aimed at elucidating the role of the adsorbed bridge-bonded formates in this reaction. Potentiodynamic measurements show a complex interplay between formation and desorption/oxidation of COad and formate species and the total Faradaic current. The notably faster increase of the Faradaic current compared to the coverage of bridge-bonded formate in transient measurements at constant potential, but with different formic acid concentrations, reveals that adsorbed formate decomposition is not rate-limiting in the dominant reaction pathway. If being reactive intermediate at all, the contribution of formate adsorption/decomposition to the reaction current decreases with increasing formic acid concentration, accounting for at most 15% for 0.2 M DCOOH at 0.7 VRHE. The rapid build-up/removal of the formate adlayer and its similarity with acetate or (bi-)sulfate adsorption/desorption indicate that the formate adlayer coverage is dominated by a fast dynamic adsorption-desorption equilibrium with the electrolyte, and that formate desorption is much faster than its decomposition. The results corroborate the proposal of a triple pathway reaction mechanism including an indirect pathway, a formate pathway, and a dominant direct pathway, as presented previously (Chen, Y. X.; et al. Angew. Chem. Int. Ed. 2006, 45, 981), in which adsorbed formates act as a site-blocking spectator in the dominant pathway rather than as an active intermediate.

  2. Acidification of calf bedding reduces fly development and bacterial abundance.

    Science.gov (United States)

    Calvo, M S; Gerry, A C; McGarvey, J A; Armitage, T L; Mitloehner, F M

    2010-03-01

    Environmental stressors, such as high fly density, can affect calf well-being. Sodium bisulfate (SBS) is an acidifier that reduces the pH of flooring and bedding, creating a medium that neither bacteria nor immature flies (also known as larvae or maggots) can thrive in. Two experiments were conducted to investigate the application of SBS to a mixture of rice hull calf bedding and calf slurry (BED) to reduce house fly (Musca domestica L.) larval density and the abundance of bacteria. In experiment 1, dish pans containing 1L of BED and 3,000 house fly eggs were treated with SBS at concentrations of 0, 8.9, 17.7, and 26.5g of SBS/0.05m(2) of BED (CON, LOW, MED, and HIGH, respectively), with each SBS concentration applied to 4 individual pans (16 pans total). Reapplication of the same SBS concentrations in each pan occurred 3 times/wk throughout the 23-d trial. Larval house fly survival was significantly reduced in all pans with SBS relative to CON pans, with lowest survival rates in the MED and HIGH pans (99% and 100% reduction, respectively). The mean pH for each treatment was inversely related to the SBS concentration. In experiment 2, pans containing 1L of BED and 3,000 house fly eggs were treated with either 0g of SBS (CON), 8.9g of SBS/0.05m(2) of BED with reapplication of the acidifier 3 times/wk (SB3x), or 8.9g of SBS/0.05m(2) of BED applied only once at 48h before the end of the 8 d-trial (SB48). Larval house fly survival and bacterial concentrations were reduced (90% larval reduction and 68% bacterial reduction) in the SB3x treatment relative to the CON. Mean pH was also reduced in SB3x pans relative to CON or SB48 pans. Overall, acidification of calf BED using the acidifier SBS resulted in a reduction of bacteria and house fly larval survival. This form of fly control might be expected to reduce adult fly production and, therefore, fly-related stress in calves.

  3. A decorin-deficient matrix affects skin chondroitin/dermatan sulfate levels and keratinocyte function

    Science.gov (United States)

    Nikolovska, Katerina; Renke, Jana K.; Jungmann, Oliver; Grobe, Kay; Iozzo, Renato V.; Zamfir, Alina D.; Seidler, Daniela G.

    2016-01-01

    Decorin is a small leucine-rich proteoglycan harboring a single glycosaminoglycan chain, which, in skin, is mainly composed of dermatan sulfate (DS). Mutant mice with targeted disruption of the decorin gene (Dcn−/−) exhibit an abnormal collagen architecture in the dermis and reduced tensile strength, collectively leading to a skin fragility phenotype. Notably, Ehlers-Danlos patients with mutations in enzymes involved in the biosynthesis of DS display a similar phenotype, and recent studies indicate that DS is involved in growth factor binding and signaling. To determine the impact of the loss of DS-decorin in the dermis, we analyzed the glycosaminoglycan content of Dcn−/− and wild-type mouse skin. The total amount of chondroitin/dermatan sulfate (CS/DS) was increased in the Dcn−/− skin, but was overall less sulfated with a significant reduction in bisulfated ΔDiS2,X (X=4 or 6) disaccharide units, due to the reduced expression of uronyl 2-O sulfotransferase (Ust). With increasing age, sulfation declined; however, Dcn−/− CS/DS was constantly undersulfated vis-à-vis wild-type. Functionally, we found altered fibroblast growth factor (Fgf)-7 and -2 binding due to changes in the micro-heterogeneity of skin Dcn−/− CS/DS. To better delineate the role of decorin, we used a 3D Dcn−/− fibroblast cell culture model. We found that the CS/DS extracts of wild-type and Dcn−/− fibroblasts were similar to the skin sugars, and this correlated with the lack of uronyl 2-O sulfotransferase in the Dcn−/− fibroblasts. Moreover, Ffg7 binding to total CS/DS was attenuated in the Dcn−/− samples. Surprisingly, wild-type CS/DS significantly reduced the binding of Fgf7 to keratinocytes in concentration dependent manner unlike the Dcn−/− CS/DS that only affected the binding at higher concentrations. Although binding to cell-surfaces was quite similar at higher concentrations, keratinocyte proliferation was differentially affected. Higher concentration of

  4. Medición de la exposición al humo ambiental de tabaco en centros de enseñanza, centros sanitarios, medios de transporte y lugares de ocio Measurement of exposure to environmental tobacco smoke in education centers, health centers, transport facilities and leisure places

    Directory of Open Access Journals (Sweden)

    María J. López

    2004-12-01

    Full Text Available Objetivos: Describir los niveles de exposición al humo ambiental de tabaco (HAT a los que está expuesta la población en diferentes espacios públicos en Barcelona. Material y método: La nicotina en fase vapor se midió mediante monitores pasivos que contenían un filtro de 37 mm de diámetro tratado con bisulfato sódico en su interior. Se tomaron muestras en colegios de primaria y secundaria, hospitales, centros de atención primaria, estaciones de tren, transportes metropolitanos, universidades, aeropuerto, restaurantes y discotecas. Resultados: Los centros de enseñanza (primaria y secundaria y los centros sanitarios presentan los niveles de exposición al HAT más bajos y en todos ellos la concentración media es Objectives: To describe levels of exposure to environmental tobacco smoke (ETS in various public places in Barcelona (Spain. Material and method: Vapor-phase nicotine was measured with passive samplers containing a sodium bisulfate treated filter with a 37 mm diameter. The places sampled were primary and secondary schools, hospitals, primary care centers, train stations, subways, universities, airports, restaurants and discotheques. Results: Primary and secondary schools and health centers had the lowest levels of ETS exposure, with mean concentrations of less than 1 μg/m3. The mean values found in transport and universities were 2.16 μg/m3 in train stations, 3.30 μg/m3 in subways, 4.30 μg/m3 in airports and 4.97 μg/m3 in universities. The highest concentrations were found in restaurants and discotheques, with mean values of 12.36 μg/m3 in restaurants and 130.65 μg/m3 in discotheques. All samples taken from primary and secondary schools, airports, subways, restaurants and discotheques contained ETS. Likewise, 90% of the samples taken from train stations and 96% of those from universities contained ETS. Seventy-nine percent of the samples from hospitals and 58% of those from primary care centers contained ETS. Conclusions

  5. Linking ATM Promoter Methylation to Cell Cycle Protein Expression in Brain Tumor Patients: Cellular Molecular Triangle Correlation in ATM Territory.

    Science.gov (United States)

    Mehdipour, P; Karami, F; Javan, Firouzeh; Mehrazin, M

    2015-08-01

    Ataxia telangiectasia mutated (ATM) is a key gene in DNA double-strand break (DSB), and therefore, most of its disabling genetic alterations play an important initiative role in many types of cancer. However, the exact role of ATM gene and its epigenetic alterations, especially promoter methylation in different grades of brain tumors, remains elusive. The current study was conducted to query possible correlations among methylation statue of ATM gene, ATM/ retinoblastoma (RB) protein expression, D1853N ATM polymorphism, telomere length (TL), and clinicopathological characteristics of various types of brain tumors. Isolated DNA from 30 fresh tissues was extracted from different types of brain tumors and two brain tissues from deceased normal healthy individuals. DNAs were treated with bisulfate sodium using DNA modification kit (Qiagen). Methylation-specific polymerase chain reaction (MSP-PCR) was implicated to determine the methylation status of treated DNA templates confirmed by promoter sequencing. Besides, the ATM and RB protein levels were determined by immunofluorescence (IF) assay using monoclonal mouse antihuman against ATM, P53, and RB proteins. To achieve an interactive correlation, the methylation data were statistically analyzed by considering TL and D1853N ATM polymorphism. More than 73% of the brain tumors were methylated in ATM gene promoter. There was strong correlation between ATM promoter methylation and its protein expression (p ATM promoter and ATM protein expression with D1853N ATM polymorphism (p = 0.01). ATM protein expression was not in line with RB protein expression while it was found to be significantly correlated with ATM promoter methylation (p = 0.01). There was significant correlation between TL neither with ATM promoter methylation nor with ATM protein expression nor with D1853N polymorphism. However, TL has shown strong correlation with patient's age and tumor grade (p = 0.01). Given the important role of cell cycle checkpoint

  6. Underpotential deposition of hydrogen on benzene-modified Pt(111) in aqueous H2SO4.

    Science.gov (United States)

    Jerkiewicz, Gregory; DeBlois, Martin; Radovic-Hrapovic, Zorana; Tessier, Jean-Pierre; Perreault, Frédéric; Lessard, Jean

    2005-04-12

    The Pt(111) electrode is modified by an overlayer of C6H6 (ads) upon its cycling in the 0.05-0.80 V range in aq H2SO4 + 1 mM C6H6. The C6H6 (ads) overlayer significantly changes the underpotential-deposited H (H(UPD)) and anion adsorption, and cyclic-voltammetry (CV) profiles show a sharp cathodic peak and an asymmetric anodic one in the 0.05-0.80 V potential range. The C6H6 (ads) layer blocks the (bi)sulfate adsorption but facilitates the adsorption of one monolayer of H(UPD). Cycling of the benzene-modified Pt(111) in benzene-free aq 0.05 H2SO4 from 0.05 to 0.80 V results in a partial desorption of C6H6 (ads) and in a partial recovery of the CV profile characteristic of an unmodified Pt(111). The peak potential of the cathodic and anodic feature is independent of the scan rate, s (10 0 to 0 kJ mol(-1) at theta(H(UPD) --> 1. The nonzero values of delta Delta G degrees testify that the adsorbing and desorbing H(UPD) adatoms interact with an energetically different substrate. The lateral interactions changed from repulsive (omega = 29 kJ mol(-1) at theta(H(UPD) --> 0) to attractive (omega = -28 kJ mol(-1) at theta(H(UPD) --> 1) as the H(UPD) coverage increases. The values of delta S degrees(ads)(H(UPD)) increase from 19 to 56 J K(-1) mol(-1), while those of delta S degrees(des)(H(UPD)) decrease from 45 to -30 J K(-1) mol(-1) with an increase of H(UPD) coverage. The values of delta H degrees(des)(H(UPD)) and delta H degrees(des)(H(UPD)) vary from 0 to 27 kJ mol(-1). The Pt(111)-H(UPD) surface bond energy at the benzene-modified Pt(111) electrode falls in the 191-218 kJ mol(-1) range and is weaker than in the case of the unmodified Pt(111) electrode in the same electrolyte.

  7. Synthesis of Foliar Fertilizer from Titanium-Bearing Blast Furnace Slag and Cultivation Experiment of Sweet Corn%由含钛高炉渣制备叶面肥及甜玉米栽培实验研究

    Institute of Scientific and Technical Information of China (English)

    张悦; 薛向欣

    2016-01-01

    The foliar fertilizer was synthesized with the titanium-bearing blast furnace slag, potassium bisulfate,citric acid,urea and magnesium oxide as raw materials by melting and chelating methods.The field cultivation experiments of sweet corns were carried out in order to evaluate the effects of the foliar fertilizer on the growth,yield,characters and the SPAD value of nitrogen,magnesium,sugar and heavy metal in grains.The results showed that the foliar fertilizer contained nutritional elements such as nitrogen, sulfur, potassium, iron, titanium and magnesium.The application of the foliar fertilizer shortened the growing period of the sweet corn by 2 days,and also made the yield,plant heights,diameters of the stem and ears,grain number per panicle,weight of single spike,and the number of efficient panicles per plant,together with the SPAD value of chlorophyll in leaves,nitrogen and magnesium in grains significantly increase. However,there was no difference in the mass fraction of sugar,titanium,vanadium and chromium in the sweet corn.In addition,mass fractions of the heavy metal elements like vanadium and chromium in the sweet corn were below the maximum residue limit set by National Standards of China.%以含钛高炉渣、硫酸氢钾、柠檬酸、尿素和氧化镁为原料,采用熔融和螯合法制备叶面肥,并通过大田栽培实验研究了该叶面肥对甜玉米生长状况、产量、性状及籽粒的氮、镁、糖和重金属质量分数的影响。结果表明,该叶面肥含有植物营养元素氮、硫、钾、镁、铁和钛;该叶面肥的施用使甜玉米生育期缩短2d;产量、株高、茎粗、穗粗、穗粒数、单穗重、单株有效穗数、叶片中叶绿素的 SPAD 值、籽粒中氮和镁的质量分数明显增加,籽粒中糖、钛、钒和铬的质量分数无明显变化,且重金属元素钒和铬的质量分数符合国家标准。

  8. Sensitivity of thermal infrared nadir instruments to the chemical and microphysical properties of UTLS secondary sulfate aerosols

    Science.gov (United States)

    Sellitto, P.; Legras, B.

    2016-01-01

    Monitoring upper-tropospheric-lower-stratospheric (UTLS) secondary sulfate aerosols and their chemical and microphysical properties from satellite nadir observations is crucial to better understand their formation and evolution processes and then to estimate their impact on UTLS chemistry, and on regional and global radiative balance. Here we present a study aimed at the evaluation of the sensitivity of thermal infrared (TIR) satellite nadir observations to the chemical composition and the size distribution of idealised UTLS sulfate aerosol layers. The extinction properties of sulfuric acid/water droplets, for different sulfuric acid mixing ratios and temperatures, are systematically analysed. The extinction coefficients are derived by means of a Mie code, using refractive indices taken from the GEISA (Gestion et Étude des Informations Spectroscopiques Atmosphériques: Management and Study of Spectroscopic Information) spectroscopic database and log-normal size distributions with different effective radii and number concentrations. IASI (Infrared Atmospheric Sounding Interferometer) pseudo-observations are generated using forward radiative transfer calculations performed with the 4A (Automatized Atmospheric Absorption Atlas) radiative transfer model, to estimate the impact of the extinction of idealised aerosol layers, at typical UTLS conditions, on the brightness temperature spectra observed by this satellite instrument. We found a marked and typical spectral signature of these aerosol layers between 700 and 1200 cm-1, due to the absorption bands of the sulfate and bisulfate ions and the undissociated sulfuric acid, with the main absorption peaks at 1170 and 905 cm-1. The dependence of the aerosol spectral signature to the sulfuric acid mixing ratio, and effective number concentration and radius, as well as the role of interfering parameters like the ozone, sulfur dioxide, carbon dioxide and ash absorption, and temperature and water vapour profile uncertainties

  9. 桑椹酒酿造工艺以及理化和营养指标分析%Study on Mulberry Wine Brewing Process and Analyze on Physical and Chemical Index and Nutrition Index

    Institute of Scientific and Technical Information of China (English)

    吴婧婧; 梁贵秋; 陆春霞

    2011-01-01

    采用桑椹为原料,运用桑椹发酵酒酿造技术与桑椹果汁浸泡工艺技术相结合可获得风味独特的桑椹酒.通过对桑椹发酵原酒主发酵的正交试验分析,结果表明:桑椹果汁中,添加初始含糖量为23%,亚硫酸氢钠含量为0.08g/L和酵母接种量为0.21g/L为最佳工艺条件.将桑椹发酵原酒和桑椹浸泡原酒按照5.6:1的比例混合之后,检测表明,桑椹酒中维生素C的含量较高,为23.3μg/100mL,维生素E的含量达到19.1μg/100mL.桑椹酒的矿物质元素含量也很高,其中微量元素硒含量为0.002mg/L.%Combined fermentation technology with original fruit soaked process could get unique flavor mulberry wine which made mulberry fruitfas raw material. Analyzed orthogonal experiment on conditions of the main fermentation of mulberry original wine, the results showed that 23% of initial sugar content, 0.08g/L of sodium bisulfate content and 0.21 g/L of yeast as the best factors of process. Mixed the mulberry of fermented original wine with mulberry of the soaked original wine in ratio of 5.6:1, the test showed that the mulberry wine was high in vitamin C content, had 23.3|Xg/100mL and vitamin E content was 19.1u,g/100mL Mulberry wine is also very high content of minerals, including microelement 0.002mg / L of selenium content.

  10. HYBRID SELECTIVE NON-CATALYTIC REDUCTION (SNCR)/SELECTIVE CATALYTIC REDUCTION (SCR) DEMONSTRATION FOR THE REMOVAL OF NOx FROM BOILER FLUE GASES

    Energy Technology Data Exchange (ETDEWEB)

    Jerry B. Urbas

    1999-05-01

    The U. S. Department of Energy (DOE), Electric Power Research Institute (EPRI), Pennsylvania Electric Energy Research Council, (PEERC), New York State Electric and Gas and GPU Generation, Inc. jointly funded a demonstration to determine the capabilities for Hybrid SNCR/SCR (Selective Non-Catalytic Reduction/Selective Catalytic Reduction) technology. The demonstration site was GPU Generation's Seward Unit No.5 (147MW) located in Seward Pennsylvania. The demonstration began in October of 1997 and ended in December 1998. DOE funding was provided through Grant No. DE-FG22-96PC96256 with T. J. Feeley as the Project Manager. EPRI funding was provided through agreements TC4599-001-26999 and TC4599-002-26999 with E. Hughes as the Project Manager. This project demonstrated the operation of the Hybrid SNCR/SCR NO{sub x} control process on a full-scale coal fired utility boiler. The hybrid technology was expected to provide a cost-effective method of reducing NO{sub x} while balancing capital and operation costs. An existing urea based SNCR system was modified with an expanded-duct catalyst to provide increased NO{sub x} reduction efficiency from the SNCR while producing increased ammonia slip levels to the catalyst. The catalyst was sized to reduce the ammonia slip to the air heaters to less than 2 ppm while providing equivalent NO{sub x} reductions. The project goals were to demonstrate hybrid technology is capable of achieving at least a 55% reduction in NO{sub x} emissions while maintaining less than 2ppm ammonia slip to the air heaters, maintain flyash marketability, verify the cost benefit and applicability of Hybrid post combustion technology, and reduce forced outages due to ammonium bisulfate (ABS) fouling of the air heaters. Early system limitations, due to gas temperature stratification, restricted the Hybrid NO{sub x} reduction capabilities to 48% with an ammonia slip of 6.1 mg/Nm{sup 3} (8 ppm) at the catalyst inlet. After resolving the stratification

  11. Measurement, analysis, and modeling of hydrogen sulfide emissions from a swine facility in North Carolina

    Science.gov (United States)

    Blunden, Jessica

    Annual global source contributions of sulfur compounds to the natural atmospheric environment are estimated to be 142 x 106 tons. Although not quantified, volatilization from animal wastes may be an important source of gaseous reduced sulfur compounds. Hydrogen sulfide (H2S) is a colorless gas emitted during decomposition of hog manure that produces an offensive "rotten egg" odor. Once released into the atmosphere, H 2S is oxidized and the eventual byproduct, sulfuric acid, may combine with other atmospheric constituents to form aerosol products such as ammonium bisulfate and ammonium sulfate. In recent years, confined animal feeding operations (CAFOs) have increased in size, resulting in more geographically concentrated areas of animals and, subsequently, animal waste. In North Carolina and across the southeastern United States anaerobic waste treatment lagoons are traditionally used to store and treat hog excreta at commercial hog farms. Currently, no state regulations exist for H2S gaseous emissions from animal production facilities in North Carolina and the amount of H2S being emitted into the atmosphere from these potential sources is widely unknown. In response to the need for data, this research initiative has been undertaken in an effort to quantify emissions of H2S from swine CAFOs. An experimental study was conducted at a commercial swine farm in eastern North Carolina to measure hydrogen sulfide emissions from a hog housing unit utilizing a mechanical fan ventilation system and from an on-site waste storage treatment lagoon. A dynamic flow-through chamber system was employed to make lagoon flux measurements. Semi-continuous measurements were made over a one-year period (2004-2005) for a few days during each of the four predominant seasons in order to assess diurnal and temporal variability in emissions. Fan rpm from the barn was continuously measured and flow rates were calculated in order to accurately assess gaseous emissions from the system

  12. On the composition of ammonia-sulfuric-acid ion clusters during aerosol particle formation

    Science.gov (United States)

    Schobesberger, S.; Franchin, A.; Bianchi, F.; Rondo, L.; Duplissy, J.; Kürten, A.; Ortega, I. K.; Metzger, A.; Schnitzhofer, R.; Almeida, J.; Amorim, A.; Dommen, J.; Dunne, E. M.; Ehn, M.; Gagné, S.; Ickes, L.; Junninen, H.; Hansel, A.; Kerminen, V.-M.; Kirkby, J.; Kupc, A.; Laaksonen, A.; Lehtipalo, K.; Mathot, S.; Onnela, A.; Petäjä, T.; Riccobono, F.; Santos, F. D.; Sipilä, M.; Tomé, A.; Tsagkogeorgas, G.; Viisanen, Y.; Wagner, P. E.; Wimmer, D.; Curtius, J.; Donahue, N. M.; Baltensperger, U.; Kulmala, M.; Worsnop, D. R.

    2015-01-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH3) and sulfuric acid (H2SO4). Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small NH3-H2SO4 clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH3] in the range from 10. Positively charged clusters grew on average by Δm/Δn = 1.05 and were only observed at sufficiently high [NH3] / [H2SO4]. The H2SO4 molecules of these clusters are partially neutralized by NH3, in close resemblance to the acid-base bindings of ammonium bisulfate. Supported by model simulations, we substantiate previous evidence for acid-base reactions being the essential mechanism behind the formation of these clusters under atmospheric conditions and up to sizes of at least 2 nm. Our results also suggest that electrically neutral NH3-H2SO4 clusters, unobservable in this study, have generally the same composition as ionic clusters for [NH3] / [H2SO4] > 10. We expect that NH3-H2SO4 clusters form and grow also mostly by Δm/Δn > 1 in the atmosphere's boundary layer, as [NH3] / [H2SO4] is mostly larger than 10. We compared our results from CLOUD with APi-TOF measurements of NH3-H2SO4 anion clusters during new-particle formation in the Finnish boreal forest. However, the exact role of NH3-H2SO4 clusters in boundary layer particle formation remains to be resolved.

  13. Do atmospheric aerosols form glasses?

    Science.gov (United States)

    Zobrist, B.; Marcolli, C.; Pedernera, D. A.; Koop, T.

    2008-09-01

    A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline) solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5), of dicarboxylic acids and ammonium sulfate (M5AS), of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K). To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol-1) and more hydrophobic organic molecules are more likely to form glasses at intermediate to high relative humidities in the upper troposphere

  14. Structure and Energetics of Nanometer Size Clusters of Sulfuric Acid with Ammonia and Dimethylamine

    Energy Technology Data Exchange (ETDEWEB)

    Depalma, Joseph W.; Bzdek, Bryan R.; Doren, Doug J.; Johnston, Murray V.

    2012-01-26

    The structures of positively and negatively charged clusters of sulfuric acid with ammonia and/or dimethylamine ((CH{sub 3}){sub 2}NH or DMA) are investigated using a combination of Monte Carlo configuration sampling, semiempirical calculations, and density functional theory (DFT) calculations. Positively charged clusters of the formula [(NH{sub 4}{sup +}){sub x}(HSO{sub 4}{sup -}){sub y}]{sup +}, where x = y + 1, are studied for 1 {le} y {le} 10. These clusters exhibit strong cation-anion interactions, with no contribution to the hydrogen-bonding network from the bisulfate ion protons. A similar hydrogen-bonding network is found for the [(DMAH{sup +}){sub 5}(HSO{sub 4}{sup -}){sub 4}]{sup -} cluster. Negatively charged clusters derived from the reaction of DMA with [(H{sub 2}SO{sub 4}){sub 3}(NH{sub 4}{sup +})(HSO{sub 4}{sup -}){sub 2}]{sup -} are also studied, up to the fully reacted cluster [(DMAH{sup +}){sub 4}(HSO{sub 4}{sup -}){sub 5}]{sup -}. These clusters exhibit anion-anion and ion-molecule interactions in addition to cation-anion interactions. While the hydrogen-bonding network is extensive for both positively and negatively charged clusters, the binding energies of ions and molecules in these clusters are determined mostly by electrostatic interactions. The thermodynamics of amine substitution is explored and compared to experimental thermodynamic and kinetic data. Ammonia binds more strongly than DMA to sulfuric acid due to its greater participation in hydrogen bonding and its ability to form a more compact structure that increases electrostatic attraction between oppositely charged ions. However, the greater gas-phase basicity of DMA is sufficient to overcome the stronger binding of ammonia, making substitution of DMA for ammonia thermodynamically favorable. For small clusters of both polarities, substitutions of surface ammonium ions are facile. As the cluster size increases, an ammonium ion becomes encapsulated in the center of the cluster, making

  15. On the composition of ammonia-sulfuric acid clusters during aerosol particle formation

    Science.gov (United States)

    Schobesberger, S.; Franchin, A.; Bianchi, F.; Rondo, L.; Duplissy, J.; Kürten, A.; Ortega, I. K.; Metzger, A.; Schnitzhofer, R.; Almeida, J.; Amorim, A.; Dommen, J.; Dunne, E. M.; Ehn, M.; Gagné, S.; Ickes, L.; Junninen, H.; Hansel, A.; Kerminen, V.-M.; Kirkby, J.; Kupc, A.; Laaksonen, A.; Lehtipalo, K.; Mathot, S.; Onnela, A.; Petäjä, T.; Riccobono, F.; Santos, F. D.; Sipilä, M.; Tomé, A.; Tsagkogeorgas, G.; Viisanen, Y.; Wagner, P. E.; Wimmer, D.; Curtius, J.; Donahue, N. M.; Baltensperger, U.; Kulmala, M.; Worsnop, D. R.

    2014-05-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH3) and sulfuric acid (H2SO4). Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small NH3-H2SO4 clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH3] in the range from 10. Positively charged clusters grew on average by Δm / Δn = 1.05 and were only observed at sufficiently high [NH3] / [H2SO4]. The H2SO4 molecules of these clusters are partially neutralized by NH3, in close resemblance to the acid-base bindings of ammonium bisulfate. Supported by model simulations, we substantiate previous evidence for acid-base reactions being the essential mechanism behind the formation of these clusters under atmospheric conditions and up to sizes of at least 2 nm. Our results also suggest that yet unobservable electrically neutral NH3-H2SO4 clusters grow by generally the same mechanism as ionic clusters, particularly for [NH3] / [H2SO4]>10. We expect that NH3-H2SO4 clusters form and grow also mostly by Δm / Δn>1 in the atmosphere's boundary layer, as [NH3] / [H2SO4] is mostly larger than 10. We compared our results from CLOUD with APi-TOF measurements of NH3-H2SO4 anion clusters during new particle formation in the Finnish boreal forest. However, the exact role of NH3-H2SO4 clusters in boundary layer particle formation remains to be resolved.

  16. Analysis of Fine Particulate Nitrate on Diurnal, Weekly and Seasonal Time Scales

    Science.gov (United States)

    Millstein, D. E.; Harley, R. A.; Hering, S. V.

    2006-12-01

    neutralization of sulfuric acid and ammonium bisulfate, rather than increased ammonia. Diurnal patterns of fine particulate nitrate were also analyzed at each site by season. Size-resolved nitrate measurements at Claremont suggest relationships among air pollution levels, meteorology, and the importance of homogenous vs. heterogeneous particulate nitrate formation mechanisms.

  17. Intumescent Coatings as Fire Retardants

    Science.gov (United States)

    Parker, J. A.; Fohlen, G. M.; Sawko, P. M.; Fish, R. H.

    1970-01-01

    The development of fire-retardant coatings to protect surfaces which may be exposed to fire or extreme heat is a subject of intense interest to many industries. A fire-retardant paint has been developed which represents a new chemical approach for preparing intumescent coatings, and potentially, is very important to fire-prevention authorities. The requirements for a superior coating include ease of application, suitability to a wide variety of surfaces and finishes, and stability over an extended period of time within a broad range of ambient temperature and humidity conditions. These innovative coatings, when activated by the heat of a fire, react to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction. Two fire-protection mechanisms thus become available: (1) the char layer retards the flow of heat, due to the extremely low thermal conductivity; and (2) water vapor and sulfur dioxide are released, providing fire quenching properties. Still another mechanism functions in cases where the char, by virtue of its high oxidation resistance and low thermal conductivity, reaches a sufficiently high temperature to re-radiate much of the incident heat load. The coatings consist of dispersions of selective salts of a nitro-amino-arornatic compound. Specifically, para-nitroaniline bisulfate and the ammonium salt of para-nitroaniline-ortho sulphuric acid (2-amino-5-nitrobenzenesulphuric acid) are used. Suitable vehicles are cellulose nitrate of lacquer grade, a nitrite-phenolic modified rubber, or epoxy-polysulfide copolymer. Three separate formulations have been developed. A solvent is usually employed, such as methylethyl ketone, butyl acetate, or toluene, which renders the coatings suitably thin and which evaporates after the coatings are applied. Generally, the intumescent material is treated as insoluble in the vehicle, and is ground and dispersed in the vehicle and solvent like an

  18. Seasonal variation and source apportionment of organic and inorganic compounds in PM2.5 and PM10 particulates in Beijing, China

    Institute of Scientific and Technical Information of China (English)

    Xingru Li; Yuesi Wang; Xueqing Guo; Yingfeng Wang

    2013-01-01

    The distribution and source of the solvent-extractable organic and inorganic components in PM2.5 (aerodynamics equivalent diameter below 2.5 microns),and PM10 (aerodynamics equivalent diameter below 10 microns) fractions of airborne particles were studied weekly from September 2006 to August 2007 in Beijing.The extracted organic and inorganic compounds identified in both particle size ranges consisted of n-alkanes,PAHs (polycyclic aromatic hydrocarbons),fatty acids and water soluble ions.The potential emission sources of these organic compounds were reconciled by combining the values of n-alkane carbon preference index (CPI),%waxCn,selected diagnostic ratios of PAHs and principal component analysis in both size ranges.The mean cumulative concentrations of n-alkanes reached 1128.65 ng/m3 in Beijing,74% of which (i.e.,831.7 ng/m3) was in the PM2.5 fraction,PAHs reached 136.45 ng/m3 (113.44 ng/m3 or 83% in PM2.5),and fatty acids reached 436.99 ng/m3 (324.41 ng/m3 or 74% in PM2.5),which resulted in overall enrichment in the fine particles.The average concentrations of SO42-,NO3-,and NH4+ were 21.3 ± 15.2,6.1 ± 1.8,12.5 ± 6.1 μg/m3 in PM2.5,and 25.8 ± 15.5,8.9 ± 2.6,16.9 ± 9.5 μg/m3 in PM10,respectively.These three secondary ions primarily existed as ammonium sulfate ((NH4)2SO4),ammonium bisulfate (NH4HSO4) and ammonium nitrate (NH4NO3).The characteristic ratios of PAHs revealed that the primary sources of PAHs were coal combustion,followed by gasoline combustion.The ratios of stearic/palmitic acid indicated the major contribution of vehicle emissions to fatty acids in airborne particles.The major alkane sources were biogenic sources and fossil fuel combustion.The major sources of PAHs were vehicular emission and coal combustion.

  19. Epigenetic silencing of MAL, a putative tumor suppressor gene, can contribute to human epithelium cell carcinoma

    Directory of Open Access Journals (Sweden)

    Zhang Jun

    2010-11-01

    Full Text Available Abstract Background To identify new and useful candidate biomarkers in head and neck squamous cell carcinoma (HNSCC, we performed a genome-wide survey and found that Myelin and lymphocyte-associated protein (MAL was a gene that was markedly down-regulated in HNSCC. Hence, we investigated the mechanism of MAL silencing and the effects of MAL on the proliferation, invasion, and apoptotic potential in HNSCC. Results MAL was significantly down-regulated in 91.7% of HNSCC specimens at the mRNA level as compared with adjacent normal tissues (P = 0.0004. Moreover, the relative transcript levels of the MAL gene were remarkably decreased by five-fold in nine HNSCC cell lines as compared with normal head and neck epithelium cells. MAL gene expression was restored in 44%, 67%, and 89% in HNSCC cell lines treated with TSA, 5-Aza-dC, and TSA plus 5-Aza-dC, respectively. Furthermore, bisulfate-treated DNA sequencing demonstrated that the two CpG islands (that is, M1 and M2 located in MAL promoter region were completely methylated in the HNSCC cell lines (CpG methylated ratio was more than 90%, and only one CpG island (that is, M1 was partially methylated in HNSCC tissues (CpG methylated ratio between 20% and 90%. A significant reduction in cell proliferation and a change in the cell cycle profile were also observed in MAL transfectants. Matrigel assay demonstrated that the invasiveness of HNSCC cells significantly decreased. A significant increase in the population of apoptotic cells was observed in MAL transfected cells. The exogenous expression of the MAL gene suppressed malignant phenotypes, while the cell death induced by MAL gene transfer was a result of apoptosis as demonstrated by the induction of cleavage of the poly (that is, ADP-ribose polymerase. Additionally, tumor growth was suppressed in cells expressing MAL as compared with cells not expressing MAL. Conclusion Our data suggest that the epigenetic inactivation of MAL, as a candidate tumor

  20. CpG promoter methylation status is not a prognostic indicator of gene expression in beryllium challenge.

    Science.gov (United States)

    Tooker, Brian C; Ozawa, Katherine; Newman, Lee S

    2016-05-01

    Individuals exposed to beryllium (Be) may develop Be sensitization (BeS) and progress to chronic beryllium disease (CBD). Recent studies with other metal antigens suggest epigenetic mechanisms may be involved in inflammatory disease processes, including granulomatous lung disorders and that a number of metal cations alter gene methylation. The objective of this study was to determine if Be can exert an epigenetic effect on gene expression by altering methylation in the promoter region of specific genes known to be involved in Be antigen-mediated gene expression. To investigate this objective, three macrophage tumor mouse cell lines known to differentially produce tumor necrosis factor (TNF)-α, but not interferon (IFN)-γ, in response to Be antigen were cultured with Be or controls. Following challenges, ELISA were performed to quantify induced TNFα and IFNγ expression. Bisulfate-converted DNA was evaluated by pyrosequencing to quantify CpG methylation within the promoters of TNFα and IFNγ. Be-challenged H36.12J cells expressed higher levels of TNFα compared to either H36.12E cells or P388D.1 cells. However, there were no variations in TNFα promoter CpG methylation levels between cell lines at the six CpG sites tested. H36.12J cell TNFα expression was shown to be metal-specific by the induction of significantly more TNFα when exposed to Be than when exposed to aluminum sulfate, or nickel (II) chloride, but not when exposed to cobalt (II) chloride. However, H36.12J cell methylation levels at the six CpG sites examined in the TNFα promoter did not correlate with cytokine expression differences. Nonetheless, all three cell lines had significantly more promoter methylation at the six CpG sites investigated within the IFNγ promoter (a gene that is not expressed) when compared to the six CpG sites investigated in the TNFα promoter, regardless of treatment condition (p beryllium had no impact on promoter methylation status, despite its ability to induce pro

  1. 扁平苔藓样药疹1例%A Case of Lichenoid Drug Eruption

    Institute of Scientific and Technical Information of China (English)

    程燕; 陈晓玫; 汪盛

    2011-01-01

    A 77-year-old man was admitted in the hospital with 7 days history of itching crythema and papules all over the body .Two months before onset of skin lesions he had taken irbesartan,metoprolol,amlodipine besylate,atorvastain calcium tablets,aspirin,clopidogrel bisulfate and esomeprazle manesiumenteric-coated tablets for cardiovascular disease.Severn days ago ,the fava bean like erythema and papules scattered appeared or the whole body,expecially on the proximal end of limbs and the trunk with intense itching .Previously,no drug allergy happened to him.Histological examination showed hyperkeratosis,acanthosis,liquefaction of basal cells and a band-like lymphocytes infiltrate in the dermis.Cytoid bodies and cosinophils were scattered in the superficial dermis .According to the medical history ,clinical manifestations and histological presentation,a diagnosis of lichenoid drug eruption was established.%患者男,77岁.全身出现红斑和丘疹,伴瘙痒7天.2个月前,患者口服"厄贝沙坦、美托洛尔、苯磺酸氨氯地平片、阿托伐他汀钙、阿司匹林、硫酸氯吡格雷、埃索美拉唑镁肠溶片"等药物.7天前,全身出现散在分布的粟粒至蚕豆大红斑和丘疹,以躯干和四肢近心端为著,瘙痒剧烈.既往无药物过敏史.左小腿胫前新鲜水疱组织病理示:表皮角化过度,棘层肥厚,基底细胞空泡样变性,真皮浅层以淋巴细胞为主的带状浸润,可见嗜酸性粒细胞及胶样小体.诊断:扁平苔藓样药疹.

  2. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    D. A. Pedernera

    2008-09-01

    Full Text Available A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulfate (M5AS, of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K. To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol−1 and

  3. Sensitivity of high-spectral resolution and broadband thermal infrared nadir instruments to the chemical and microphysical properties of secondary sulfate aerosols in the upper-troposphere/lower-stratosphere

    Science.gov (United States)

    Sellitto, Pasquale; Legras, Bernard

    2016-04-01

    the brightness temperature (BT) spectra observed by satellite instruments. We isolated a marked and typical spectral signature of these aerosol layers between 700 and 1200 cm-1, due to the absorption bands of the sulfate and bisulfate ions and the undissociated sulfuric acid, with the main absorption peaks at 1170 and 905 cm-1 (sulfuric acid vibrational bands). The dependence of the residual aerosol spectral BT signature to the sulfuric acid mixing ratio, and effective number concentration and radius, as well as the role of interfering parameters like the ozone, sulfur dioxide, carbon dioxide and ash absorption, and temperature and water vapour profile uncertainties, are analysed and critically discussed. The information content (degrees of freedom and retrieval uncertainties) of synthetic satellite observations is estimated for different instrumental configurations. High spectral resolution (Infrared Atmospheric Sounding Interferometer (IASI)-like pseudo-observations) and broadband spectral features (Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI)-like pseudo-observations) approaches are proposed and discussed.

  4. Seasonal variations and evidence for the effectiveness of pollution controls on water-soluble inorganic species in total suspended particulates and fine particulate matter from Xi'an, China.

    Science.gov (United States)

    Shen, Zhenxing; Arimoto, Richard; Cao, Junji; Zhang, Renjian; Li, Xuxiang; Du, Na; Okuda, Tomoaki; Nakao, Shunsuke; Tanaka, Shigeru

    2008-12-01

    Total suspended particulate (TSP) and particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) samples were collected over Xi'an for a 1-yr period to characterize the seasonal variations of water-soluble inorganic ions and to evaluate the effectiveness of the pollution policies and controls during the past 10 yr. Mass concentrations of five cations (sodium [Na+], potassium [K+], ammonium [NH4+], calcium [Ca2+], and magnesium [Mg2+]) and four anions (fluoride [F-], chloride [Cl-], nitrate [NO3-], and sulfate [SO4(2-)]) were determined by ion chromatography. The yearly arithmetic-mean mass concentrations of the total measured water-soluble ions in TSP and PM2.5 were 83.9 +/- 58.4 and 45 +/- 34.3 microg x m(-3). The most abundant ions in TSP were SO4(2-), NO3-, Ca2+, and NH4+; whereas in PM2.5 the dominant ions were SO4(2-), NH4 +, and NO3-. Most of the ions were more concentrated in the PM2.5 than in TSP, but two exceptions were Ca2+ and Mg2+. Comparisons of the molar ratios of Mg2+/Ca2+ in TSP indicated that fugitive dust was the main source for these two ions, and the influence of soil dust from outside of the city was most evident during dust storms. The mass concentrations of SO4(2-), NO3-, , NH4+, and K+ in TSP were highest in winter and lowest in spring, but Ca2+ was much higher in spring than other seasons because of suspended mineral dust. In PM2.5, NO3- and K+ also showed winter maxima, but SO4(2-) and NH4+ were highest in summer. Calculations of ion equivalents showed that TSP samples were more alkaline than PM2.5, the latter being weakly acidic in winter and autumn. High sulfur and nitrogen oxidation ratios occurred in summer and autumn, and there was evidence for the formation of ammonium bisulfate in TSP, ammonium sulfate in PM2.5, and ammonium nitrate in both fractions. Comparisons with the results of prior studies indicate that pollution controls in Xi'an have reduced the levels of air pollution over the past 10 yr. The SO4

  5. Sensitivity of transatlantic dust transport to chemical aging and related atmospheric processes

    KAUST Repository

    Abdelkader, Mohamed

    2017-03-20

    We present a sensitivity study on transatlantic dust transport, a process which has many implications for the atmosphere, the ocean and the climate. We investigate the impact of key processes that control the dust outflow, i.e., the emission flux, convection schemes and the chemical aging of mineral dust, by using the EMAC model following Abdelkader et al. (2015). To characterize the dust outflow over the Atlantic Ocean, we distinguish two geographic zones: (i) dust interactions within the Intertropical Convergence Zone (ITCZ), or the dust–ITCZ interaction zone (DIZ), and (ii) the adjacent dust transport over the Atlantic Ocean (DTA) zone. In the latter zone, the dust loading shows a steep and linear gradient westward over the Atlantic Ocean since particle sedimentation is the dominant removal process, whereas in the DIZ zone aerosol–cloud interactions, wet deposition and scavenging processes determine the extent of the dust outflow. Generally, the EMAC simulated dust compares well with CALIPSO observations; however, our reference model configuration tends to overestimate the dust extinction at a lower elevation and underestimates it at a higher elevation. The aerosol optical depth (AOD) over the Caribbean responds to the dust emission flux only when the emitted dust mass is significantly increased over the source region in Africa by a factor of 10. These findings point to the dominant role of dust removal (especially wet deposition) in transatlantic dust transport. Experiments with different convection schemes have indeed revealed that the transatlantic dust transport is more sensitive to the convection scheme than to the dust emission flux parameterization. To study the impact of dust chemical aging, we focus on a major dust outflow in July 2009. We use the calcium cation as a proxy for the overall chemical reactive dust fraction and consider the uptake of major inorganic acids (i.e., H2SO4, HNO3 and HCl) and their anions, i.e., sulfate (SO42−), bisulfate

  6. Study on Synthesis and Performance of Alkylsilane Modified Polystyrene (PS) -Polyacrylate(PA) Emulsion with High Alkylsilane Content%高硅含量硅-苯丙乳液的合成及性能研究

    Institute of Scientific and Technical Information of China (English)

    刘兴; 邱藤; 何立凡; 张胜文; 李效玉

    2012-01-01

    以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、苯乙烯(St)为主要原料,以乙烯基三甲氧基硅烷(A-171)为改性单体,以烯丙基聚乙氧基磺酸盐(SE - 10N)和十二烷基苯磺酸钠(DSB)为混合乳化剂,采用水溶性引发剂过硫酸铵(APS)和亚硫酸氢钠(SBS)与油溶性引发剂偶氮二异丁腈(AIBN)2种引发体系相配合的方式,通过烷氧基硅烷和苯乙烯混合单体对丙烯酸酯种子乳液先渗透溶胀,再进行聚合的方法(单体渗透法)合成了A - 171含量高达50%的硅-苯丙乳液.利用傅里叶变换红外光谱仪对聚合物结构进行了分析,证明了A-171的引入,通过透射电子显微镜(TEM)对粒子形态、粒径分布进行了表征,用原子力显微镜(AFM)、扫描电子显微镜(SEM)相结合的方法对乳液的成膜性能以及成膜助剂的作用进行了分析.最后通过性能测试证明,A -171含量的提高有利于降低涂膜的吸水率,增强涂膜的热稳定性.%A stable alkylsilane modified polystyrene( PS) - polyacrylate( PA) emulsion with high alkylsilane content (50% ) was prepared via a monomer penetration method. In the synthesis,methyl methacrylate (MMA) ,butyl acrylate (BA) ,styrene (St) were used as main monomers,and vinyl trimethoxysilane ( A - 171 ) as the modification monomer,1 - nonylphenyloxy -2 - deca( oxyethylene) - 3 - allyloxypropane ammonium sulfate ( SE - ION) and sodium alkylated diphenyl ether disulfonate ( DSB ) as emislsifiers,water - soluble ammonium persulfate ( APS) ,sodium bisulfate ( SBS) and oil - soluble 2,2' - azobis (isobutyronitrile) (AIBN) as compound initiator system. A -171 was pre -mixed with St and swelled in the PA seed emulsion for the stable polymerization of A - 171 with high content. The structure of the copoly-mer was analyzed by Fourier transform infrared spectroscopy ( FT - IR) . The size and structure of latex particles were analyzed by transmission electron microscope ( TEM) . The scanning electron microscope

  7. On the composition of ammonia-sulfuric acid clusters during aerosol particle formation

    Directory of Open Access Journals (Sweden)

    S. Schobesberger

    2014-05-01

    were only observed at sufficiently high [NH3] / [H2SO4]. The H2SO4 molecules of these clusters are partially neutralized by NH3, in close resemblance to the acid-base bindings of ammonium bisulfate. Supported by model simulations, we substantiate previous evidence for acid-base reactions being the essential mechanism behind the formation of these clusters under atmospheric conditions and up to sizes of at least 2 nm. Our results also suggest that yet unobservable electrically neutral NH3-H2SO4 clusters grow by generally the same mechanism as ionic clusters, particularly for [NH3] / [H2SO4]>10. We expect that NH3-H2SO4 clusters form and grow also mostly by Δm / Δn>1 in the atmosphere's boundary layer, as [NH3] / [H2SO4] is mostly larger than 10. We compared our results from CLOUD with APi-TOF measurements of NH3-H2SO4 anion clusters during new particle formation in the Finnish boreal forest. However, the exact role of NH3-H2SO4 clusters in boundary layer particle formation remains to be resolved.

  8. 环境空气中尼古丁的气相色谱-质谱测定法%Determination of Environmental Air Nicotine by Gas Chromatograph-Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    董小艳; 王秦; 徐东群

    2011-01-01

    目的 采用被动式采样器采样,气相色谱-质谱法测定环境空气中尼古丁.方法 环境空气中的尼古丁用经过NaHS04处理过的玻璃纤维滤膜采集,滤膜经1.5 mol/L NaOH洗脱和正庚烷萃取后经气相色谱分离,采用质谱选择离子扫描方式采集数据,保留时间和特征离子定性,并以喹啉作为内标物进行定量.结果 该方法的检出限为0.01 μg/ml,定量下限0.034μg/ml,按采样体积312 L计,线性范围为0.22~16μg/m3.低、中、高3个浓度的标准溶液6次测定的RSD分别为8.4%,6.0%和4.9%;3个浓度的加标回收率范围分别为82.8%~97.4%,94.0%~109.8%和85.4%-109.8%.结论 本方法采样方便,测定灵敏、准确,可以在场所监测或人群个体暴露环境烟草烟雾(ETS)监测中大规模使用,为客观评价ETS暴露提供技术手段.%Objective To establish a method for the determination of environmental air nicotine by passive diffusion sampling and chromatograph-mass spectrometry analysis. Methods The environmental air nicotine was collected onto the filter treated with sodium bisulfate by diffusing first, and then desorbed and extracted into the solution of 1.5 mol/L sodium hydroxide and heptane from the filter, the nicotine in the heptane was analyzed by gas chromatograph-mass spectrometry with SIM (selected ion monitoring), quinoline was used as internal standard to quantitative analysis. Results The limit of detection was 0.01 μg/ml and the limit of quantification was 0.034 μg/ml, the linear range of the method was 0.22-16 μg/m3 with 312 L sampling volume, the relative standard deviations of three levels concentrations were 8.4%, 6.0% and 4.9% respectively, and the recovery range of three levels concentrations were 82.8%-97.4%,94.0%-109.8% and 85.4%-109.8% respectively. Conclusion The method is convenient with the passive sampling, sensitive and accurate with gas chromatograph-mass spectrometry, it can be used in field study for

  9. Soil analyses for 1,3-dichloropropene (1,3-DCP), sodium n-methyldithiocarbamate (metam-sodium), and their degradation products near Fort Hall Idaho, September 1999 through March 2000

    Science.gov (United States)

    Parliman, D.J.

    2001-01-01

    Between September 1999 and March 2000, soil samples from the Fort Hall, Idaho, area were analyzed for two soil fumigants, 1,3-dichloropropene (1,3-DCP) and sodium n-methyldithiocarbamate (metam-sodium), and their degradation products. Ground water is the only source of drinking water at Fort Hall, and the purpose of the investigation was to determine potential risk of ground-water contamination from persistence and movement of these pesticides in cropland soils. 1,3-DCP, metam-sodium, or their degradation products were detected in 42 of 104 soil samples. The samples were collected from 1-, 2-, and 3-foot depths in multiple backhoe trenches during four sampling events—before pesticide application in September; after application in October; before soil freeze in December; and after soil thaw in March. In most cases, concentrations of the pesticide compounds were at or near their laboratory minimum reporting limits. U.S. Environmental Protection Agency Method 5035 was used as the guideline for soil sample preparation and analyses, and either sodium bisulfate (NaHSO4), an acidic preservative, or pesticide-free water was added to samples prior to analyses. Addition of NaHSO4 to the samples resulted in a greater number of compound detections, but pesticide-free water was added to most samples to avoid the strong reactions of soil carbonate minerals with the NaHSO4. As a result, nondetection of compounds in samples containing pesticide-free water did not necessarily indicate that the compounds were absent. Detections of these compounds were inconsistent among trenches with similar soil characteristics and histories of soil fumigant use. Compounds were detected at different depths and different trench locations during each sampling event. Overall results of this study showed that the original compounds or their degradation products can persist in soil 6 months or more after their application and are present to at least 3 feet below land surface in some areas. A few of

  10. Highly sensitive detection of DNA methylation levels by using a quantum dot-based FRET method

    Science.gov (United States)

    Ma, Yunfei; Zhang, Honglian; Liu, Fangming; Wu, Zhenhua; Lu, Shaohua; Jin, Qinghui; Zhao, Jianlong; Zhong, Xinhua; Mao, Hongju

    2015-10-01

    amplification for the incorporation of Alexa Fluor-647 (A647) fluorophores. DNA methylation levels can be detected qualitatively through gel analysis and quantitatively by the signal amplification from QDs to A647 during FRET. Furthermore, the methylation levels of three tumor suppressor genes, PCDHGB6, HOXA9 and RASSF1A, in 20 lung adenocarcinoma and 20 corresponding adjacent nontumorous tissue (NT) samples were measured to verify the feasibility of the QD-based FRET method and a high sensitivity for cancer detection (up to 90%) was achieved. Our QD-based FRET method is a convenient, continuous and high-throughput method, and is expected to be an alternative for detecting DNA methylation as a biomarker for certain human cancers. Electronic supplementary information (ESI) available: Synthesis of CdSe/CdS/ZnS core/shell/shell QDs. Sequences of primers used for amplifying the promoter regions in bisulfate-modified DNA. Comparison of detected methylation levels in different gene promoters using the QD-based FRET method versus bisulfite pyrosequencing. Methylation levels of the RASSF1A gene in one pair of NT and cancer samples as indicated by pyrosequencing. Theoretical calculation of the Förster distance R0. See DOI: 10.1039/c5nr04956c

  11. Effect of Adjustable Acid Medium on the Appearance and Particles Size of Pendimethalin Microcapsules%调酸介质对二甲戊灵微胶囊囊形及粒径的影响

    Institute of Scientific and Technical Information of China (English)

    罗湘仁; 徐妍; 冯建国; 马超; 严寒; 吴学民

    2012-01-01

    [目的]优选出原位聚合法制备二甲戊灵微胶囊的较佳调酸介质,为二甲戊灵的微胶囊化提供一定的理论指导.[方法]以脲醛树脂为壁材采用原位聚合法制备了二甲戊灵微胶囊,研究了不同调酸介质对二甲戊灵微胶囊囊形及粒径的影响.[结果]5%盐酸溶液作为调酸介质形成的微胶囊囊形粗糙,产生粘连,粒径分布较宽;5%硝酸铵溶液、5%硫酸氢铵溶液作为调酸介质形成的微胶囊囊形松散,容易破裂,产生粘连,粒径分布较窄;5%氯化铵溶液作为调酸介质形的微胶囊囊形光滑致密且坚固,粒径分布较窄.[结论]调酸介质对原位聚合法制备的微胶囊囊形及粒径影响很大,选择合适的调酸介质能获得囊形致密、粒径分布窄的微胶囊.%[Aims] In this paper we optimized the adjustable acid medium for microcapsules of pendimethalin by an in-situ condensation polymerization reaction in order to provide some theoretical guidance for pendimethalin microencapsulation. [Methods] Microcapsules of pendimethalin with a urea-formaldehyde resin wall were prepared by an in-situ condensation polymerization reaction, and the effect of different adjustable acid mediums on the appearance and particles size distribution of the microcapsules were investigated. [Results] When using 5% hydrogen chloride solution as adjustable acid medium, microcapsules could be formed with rough surface and wide-range particle size distribution. When using 5% ammonium nitrate solution or 5% ammonium bisulfate solution as adjustable acid medium, microcapsules which were easy to fall into fracture and conglutination could be formed with narrow-range size distribution, meanwhile, the surface of microcapsules were uncontinuous. When using 5% ammonia chloride solution as adjustable acid medium, microcapsules could be obtained with smooth and compact surface, and the particle size of microcapsules were uniform. [Conclusions] Adjustable acid

  12. Liquefaction of wheat straw catalyzed by acidic ionic liquid and analysis of liquefied products%酸性离子液体催化麦秸液化及其产物分析

    Institute of Scientific and Technical Information of China (English)

    关倩; 蒋剑春; 徐俊明; 王奎; 冯君锋

    2016-01-01

    With the increasing energy requirements and pollution problems worldwide, energy from renewable resources has received global attention in recent decades. Biomass is one of the most abundant renewable resources. It mainly includes forest residues, agricultural wastes, industrial residues, municipal solid wastes, bagasse, aquatic plants, and algae animal wastes. Due to the advantages of abundance, non-polluting, being renewable and easy to obtain, biomass is considered as the most promising energy feedstock to replace the traditional energy. Meanwhile, it is the only resource that can be converted into solid, liquid, and gaseous products for use of fuels. Thermo-chemical conversion is an effective technology of biomass conversion. Liquefaction is the typical thermo-chemical technology for the conversion of biomass to obtain liquid biofuels and valuable chemicals, such as bio-oil and fuel additives. The conversion process is not only influenced by organic reagents but also by different catalysts. Effective catalyst is an essential factor to improve liquefaction efficiency. As catalyst, sulfuric acid has very strong corrosion and needs high-quality liquefaction equipment, and its recycling is difficult. Solid acid is used to overcome shortcomings of organic acid in the liquefaction, but it is easy to form coke to cause the deactivation of catalyst, and needs to be calcined before re-use, which increases the reaction cost. Now, it is found that the ionic liquid has non-corrosiveness, low melting point, high thermal stability and low vapor pressure, and some other merits. It has a broad application prospect used as solvents and catalysts in catalytic reactions. Ionic liquid, especially sulfonated bisulfate ionic liquid can dissolve cellulose, because it has higher acidic sites that can easily break the hydrogen bonds of biomass material, and promote the degradation and conversion of cellulose. At present, ionic liquid is usually used to catalyze carbohydrate, which is

  13. 地西他滨抗套细胞淋巴瘤胞株Jeko-1作用机制的研究%The mechanisms of action of decitabine against Jeko-1 MCL cell line

    Institute of Scientific and Technical Information of China (English)

    耿梅; 费爱梅; 刘静静; 聂瑞敏; 王瑾; 糜坚青

    2011-01-01

    背景与目的:套细胞淋巴瘤(mantle cell lymphoma,MCL)是一种难治性的恶性肿瘤,预后差.地西他滨对骨髓异常增生综合征及难治性急性髓性白血病的治疗临床上已达成共识,但是目前鲜有地西他滨对MCL作用的报道.本文探讨地西他滨抗MCL细胞的作用机制.方法:以MCL细胞株Jeko-1作为研究对象,采用MTT法检测地西他滨对细胞增殖的影响,Annexin V/PI双重染色法检测其对细胞凋亡的影响,采用DiOC6(3)染色/流式细胞术检测Jeko-1细胞线粒体跨膜电位的丢失,Western blot检测细胞周期蛋白D1(Cyclin D1)及凋亡途径相关蛋白的表达,用亚硫酸氢盐测序(bisulfate sequencing PCR,BSP)技术检测地西他滨作用Jeko-1细胞前后PCDH8基因启动子CpG岛的甲基化水平变化.结果:地西他滨能有效抑制Jeko-1细胞的增殖并诱导其凋亡,凋亡率呈时间和剂量依赖性增加,并引起MCL细胞线粒体跨膜电位丢失,Cyclin D1蛋白表达水平降低,caspase 3、caspase 9表达水平增加.本研究另发现Jeko-1细胞中PCDH8基因启动子CpG岛的甲基化率为76.67%,经过0.5 μmol/L低浓度的地西他滨处理72 h后,其甲基化率下降至48.33%.结论:地西他滨在对MCL细胞的作用中,高浓度时起到细胞毒作用,低浓度时则具有去甲基化作用,为今后的临床治疗提供了新的理论依据.%Background and purpose: Mantle cell lymphoma (MCL) is one of the refractory malignant tumors with very poor prognosis.The treatment of decitabine against myelodysplastic syndrome and refractory acute myeloid leukemia has been widely applied.However, the effectiveness of decitabine against MCL cell lines has not been reported.This study was to explore the mechanisms of action of decitabine (DAC) against Jeko-1 MCL cell line.Methods: Jeko-1 cells were treated with different concentrations of DAC, cell growth rate was detected by MTT assay.Apoptosis of Jeko-1 cells treated with DAC was detected by using flow

  14. 替格瑞洛联合阿司匹林治疗急性冠状动脉综合征的临床研究%Clinical trial of ticagrelor combined with aspirin in the treatment of acute coronary syndrome

    Institute of Scientific and Technical Information of China (English)

    贾珠银; 杨建敏

    2016-01-01

    -domly divided into control group (n=42) and treatment group(n=42). Two groups were received aspirin 150 mg oral, qd +clopidogrel bisulfate 300 mg oral, qd for 7 days before operative.Control group was received aspirin 100 mg oral, qd for 6 months after operation.Treatment group was received aspirin 100 mg oral, qd, and ticagrelor 90 mg oral, qd for 6 months.The clinical efficacy , the number of acute myocardial infarction , the levels of ST segment depression , serum cardiac troponin T ( cTnT ) , brain natriuretic peptide (BNP), C reactive protein (CRP), D-dimer, and incidence of adverse drug reactions were compared between two groups.Results After treatment , the total effective rate of treatment group was 95.24%( 40/42 ) , which was significantly higher than that of control group [ 83.33%( 35/42 ) , P<0.05 ] .After treatment , the main observation indexes in treatment and control group: the attack times of acute myocardial infarction were ( 2.02 ±0.23 ) , (4.53 ±0.52) times per week;the attack duration were (2.76 ±0.31), (4.14 ±0.43)min each time; the down level of ST were ( 0.63 ±0.07 ) , ( 1.25 ±0.17 ) mV; cTnT were ( 0.25 ±0.03 ) , ( 1.54 ±0.18 ) ng・ mL-1; BNP were ( 28.43 ±3.02 ) , ( 63.52 ±6.73 ) ng・ L-1; CRP were ( 4.57 ±0.55 ) , ( 8.94 ±0.94 ) mg・ L-1; D-dimer were (59.54 ±61.74), (133.53 ±15.73)ng・ mL-1, and the attack times of acute myocardial infarction , the attack duration, the down level of ST, the levels of cTnT, BNP, CRP and D-dimer in treatment group were significantly lower than those of control group ( P<0.05 ).The adverse drug reactions were based on digestive and nervous system symptoms for two groups.Also, the incidence of adverse drug reactions in control group was 16.67%, treatment group was 7.14%, the difference had statistically significant difference ( P<0.05 ) .Conclusion Ticagrelor combined with aspirin in the treatment of acute coronary syndrome was effective and safety .

  15. Effects of sodium arsenite on hypermethylation, transcription and expression of O6-methylguanine-DNA methyltransferase gene in HaCaT cells%亚砷酸钠对HaCaT细胞MGMT基因甲基化和mRNA及蛋白表达水平的影响

    Institute of Scientific and Technical Information of China (English)

    潘雪莉; 张爱华

    2011-01-01

    Objective To investigate the DNA methylation feature and DNA methylation regulation to its transcription and expression of O6-methylguanine-DNA methyltransferase gene (MGMT) in NaAsO2-treated HaCaT cells. Methods HaCaT cells were treated 72 hours at intervals and repeatedly by 3.13, 6.25,12.50, and 25.00 μmol/L NaAsO2, MGMT gene promoter region was amplified in the transcription initiation site - 329 - + 93 region by bisulfate-sequencing polymerase chain reaction (BSP), the mRNA transcription and the protein expression of MGMT was detected by real-time quantitative PCR and Western blotting. NaAsO2-untreated HaCaT cell was set as a blank control, and human epidermal squamous carcinoma cell strain A431 was set as a positive control. Results Among the groups of HaCaT cells treated with 3.13, 6.25, 12.50 and 25.00 μmol/L NaAsO2, the positive rates of the DNA methylation of promoter region in MGMT gene were 0.63%(l/160), 6.25% (10/160), 10.63%( 17/160) and 18.75% (30/160), respectively, and methylated CpG sites were mainly located in - 249--146 region relative to transcription start site. There was no DNA methylation in the blank control. There were significant differences between the blank control and the NaAsO2-treated cells (x2 = 76.687, P< 0.05). Average levels of MGMT mRNA were 1.518 31 ± 0.180 54, 1.425 22 ± 0.180 39, 1.014 54 ± 0.096 79 and 0.887 72 ± 0.020 00, respectively among the groups of HaCaT cells treated with 3.13, 6.25, 12.50 and 25.00 μmol/L NaAsO2, compared with the blank control cells(1.198 29 ± 0.159 97), there were significant differences(F = 37.359, P < 0.05). Average levels of MGMT protein were 1.174 47 ± 0.064 75, 0.848 83 ± 0.057 01, 0.471 63 ± 0.023 34 and 0.240 34 ± 0.014 43, respectively among the groups of HaCaT cells treated with 3.13, 6.25, 12.50 and 25.00 μmol/L NaAsO2, compared with the blank control cells (1.066 19 ± 0.061 24), there were significant differences(F = 20.687, P < 0.05). Conclusions Arsenic can cause Cp

  16. A Clinical Study of Clopidogrel Combined with Betahistine,Danshen Injection in the Treatment of Vertigo of VBI%国产氯吡格雷联合倍他司汀、复方丹参注射液治疗椎基底动脉供血不足所致眩晕的临床研究

    Institute of Scientific and Technical Information of China (English)

    赵忠东; 刘坤; 李君; 胡臣

    2015-01-01

    Objective:To evaluate the efficacy and safety of Clopidogrel Betahistine,Danshen injection in the treatment of vertebral basilar insufficiency(Vertebral-basilar artery insufficiency,VBI). Method:Inclusion and exclusion criteria in strict accordance with VBI patients enrolled 120 cases,according to a list of random numbers into the treatment group of 60 patients received Betahistine 10-30 mg,5%dextrose injection or 0.9%sodium chloride injection, a after day 1,Danshen injection,intravenous infusion,a 10-20 mL with 5%glucose injection 100-500 mL diluted after use,day 1,and oral Clopidogrel bisulfate tablets,for the first time to give 600 mg,150 mg/d. The control group received betahistine joint compound Danshen injection. Two consecutive 7-21 d after treatment to assess the extent of the patient’s vertigo,and using TCD to detect vertebral-basilar artery blood flow velocity and blood rheology,and follow 30 d,observed the occurrence of recent TIA or cerebral infarction. Result:The treatment group was 0-2 h from patients and 0-6 h effective accounting effect from patients was 48.3%,36.7%. The proportion of patients in the control group 0-2 h onset patients and 0-6 h onset was 28.3%,58.3%. Treatment group was efficient,the total efficiency was 65.0%and 93.3%, respectively,in the control group significant efficiency,total efficiency of 41.7% and 75.0 %. There was significant difference between the two groups(P<0.05). After the triple therapy treatment group left vertebral artery,right vertebral artery,basilar artery blood flow velocity,blood viscosity,plasma viscosity,erythrocyte aggregation index improved significantly better than the control group,a significant difference between the two groups(P<0.05). Long-term follow 30 d,the treatment group 0 case of TIA or stroke occurred in the control group four cases occurred TIA,1 case developed into stroke incidence was 9.2%. There was significant difference between the two groups(χ² =4.627,P=0.031). Both groups during the

  17. ABO血型不合肝移植治疗急危重症肝病患者的临床疗效分析%Analysis of the curative effect of ABO-incompatible liver transplantation in the treatment in patients with acute severe liver disease

    Institute of Scientific and Technical Information of China (English)

    沈中阳; 邓永林; 郑虹; 潘澄; 张雅敏; 蒋文涛; 张建军; 高伟; 淮明生

    2014-01-01

    Objective To analyze and evaluate the clinical effect of ABO-incompatible liver transplantation in the treatment of acute severe liver disease.Methods A retrospective clinical study was conducted.The clinical data of 4 136 patients undergoing orthotopic liver transplantation in Organ Transplantation Center of Tianjin First Center Hospital from September 1999 to December 2013 were analyzed.The criteria of patients enrolled were as following:model for end-stage liver disease (MELD) score ≥ 20,the donor's and recipient's blood types were different,age 18-70 years,and undergone primary non-bypass orthotopic liver transplantation.According to the rate of compliance with the principles of blood transfusion,the cases were divided into two groups:ABO-compatible group (ABO-C group,n =41),ABO-incompatible group (ABO-I group,n =22).The patients in ABO-I group received basiliximab + methylprednisolone for immune induction therapy during operation,basiliximab + tacrolimus + mycophenolate + cortisol as quadruple immunosuppressive regimen after operation.They also received subcutaneous injection of low molecular heparin for anticoagulant therapy after operation,and oral warfarin or aspirin and clopidogrel bisulfate instead after 7 days.They also received routine alprostadil after operation.The remaining treatment was the same as that of ABO-C group.The clinical data,postoperative complications,rejection and survival rates of two groups were statistically analyzed.Results There were no significant differences in gender,age,MELD score,complicated with tumor,quality of donor liver,length of cold preservation of donor liver,duration of operation,and blood loss during operation between ABO-C and ABO-I groups.Number of splenectomy during operation was significantly higher in ABO-I group than that in ABO-C group (5 cases vs.1 case,x2=4.687,P=0.030).The 3-month,6-month,1-year,3-year and 5-year survival rates of ABO-C group were 89.5%,78.3%,72.5%,69.1% and 61.8

  18. 《化学通报》网络版(Chemistry Online)2001年4月论文摘要

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    有不同的反应途径,使用不同的催化剂及合成工艺。其中某些产品的三步法非光气合成已经接近成熟。催化剂性能改进和工艺过程开发是这些合成技术工业化的关键。   There are different kinds of technology for the non\\|phosgenation processes for synthesis of isocyanates according to the stage of reaction,i.e. one\\|stage,two\\|stage and three stage reactions.This review focus on the catalysts,mechanism and technologies of these processes.Three\\|stage reaction technology for synthesis of some isocyanates is about to be commercialized.The successful industrialization will depend on the development of the synthesis routes and the improvement of the performance of catalysts. [W01034] 污染生态化学与生物信息代谢* Pollution Ecology Chemistry and Biological Information Metabolism 徐维并 许后效 (中国科学院生态环境研究中心 北京 100085)   本文提出代谢信息分子新概念,并阐述了烷化核酸碱基和一氧化氮这两个代谢信息分子作为污染生态化学与生物信息代谢相互关系的表达。   This paper raised a new concept concerning the metabolic information molecule,and it was expounded that the metabolic information moleculars of both alkylated nucleic acid bases and nitric oxide as an expression ion of interrelation between pollution ecology chemistry and biological information metabolism. [W01035] 硫酸氢钠催化合成丁酸异戊酯的研究 Study on the Catalytic Synthesis of Isoamyl Butyrate by Sodium Bisulfate 刘华亭 林 进 (河北师范大学化学系 石家庄 050016)   研究了以硫酸氢钠为催化剂,丁酸和异戊醇为原料合成丁酸异戊酯,并考察了影响反应的因素。结果表明,醇酸摩尔比为1.2∶1,催化剂用量为0.5g(丁酸为0.2mol的情况下),带水剂甲苯为10mL,反应时间为1.0h是最适宜的反应条件,酯化率达99.2%。