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1.
ACS Sens ; 4(4): 1017-1022, 2019 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-30895782

RESUMO

We present here an innovative platform for the determination of pH buffer capacity based on FITC-dextran loaded hydrogels. Optical signals from the pH-sensitive hydrogels were analyzed by simple parameters including distance and color change. The methodology was validated on five different buffer systems and exhibited wide linearity (0.1 to 100 mM), good batch-to-batch reproducibility, high versatility, and resistance to background ionic strength changes. Experimental results also fit well with a theoretical model based on numerical simulation. Preliminary application in carbonate alkalinity determination of seawater proved very successful. This hydrogel buffer concentration sensor is fundamentally different from conventional acid-base titrations, brings minimum perturbation to samples, and shows great potential in real applications.


Assuntos
Ácidos não Carboxílicos/análise , Álcalis/análise , Dextranos/química , Fluoresceína-5-Isotiocianato/análogos & derivados , Hidrogéis/química , Sefarose/química , Trometamina/análise , Tampões (Química) , Cor , Fluoresceína-5-Isotiocianato/química , Concentração de Íons de Hidrogênio , Água do Mar/análise , Espectrofotometria Ultravioleta/métodos
2.
Chemosphere ; 193: 278-287, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29145088

RESUMO

Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H2SO4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid.


Assuntos
Fósforo/isolamento & purificação , Reciclagem/métodos , Esgotos/química , Oligoelementos/isolamento & purificação , Ácidos não Carboxílicos , Ácidos Carboxílicos , Quelantes , Ácido Edético , Incineração , Metais/isolamento & purificação , Fósforo/química , Oligoelementos/química
3.
Food Chem ; 221: 898-906, 2017 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-27979291

RESUMO

This paper proposed a nonlinear chemical fingerprint method for simultaneous determination of urea and melamine in milk powder using "H++Ce4++BrO3-+malonic acid" as reaction system. A multiple linear relationship was obtained between the adulterants content in milk powder and inductive time of corresponding mixed milk powder. System analysis model established with classical least squares (CLS) method was then used to calculate the content of urea and melamine in milk powder. The method was successfully applied to milk powder samples and had good recoveries in the range of 99.17-100.25%, with the relative standard deviation (RSD) in the range of 0.60-4.12%. The limits of detection for urea and melamine were 0.33µg·g-1 and 0.05µg·g-1, respectively. The limits of quantification were 1.11µg·g-1 and 0.18µg·g-1, respectively. The results indicated that the new method was feasible and had the advantages of low cost, simple operation and without pretreatment of samples.


Assuntos
Técnicas Eletroquímicas/métodos , Leite/química , Triazinas/análise , Ureia/análise , Ácidos não Carboxílicos , Animais , Cério , Contaminação de Alimentos/análise , Limite de Detecção , Malonatos , Pós/química
4.
Dermatol Ther ; 30(2)2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27917575

RESUMO

Treating plantar, periungual, and external genital warts can be challenging. A prospective study from four centers in Italy evaluated 37 immunocompetent patients with single or multiple warts and treated each lesion with a nitric-zinc topical solution composed of organic and inorganic acids meant to devitalize tissue and destroy HPV DNA in infected keratinocytes. Thirty of the 37 patients had external genital warts, two had plantar warts, two had palm and finger warts, and three had subungual warts for a total of 55 lesions treated. Nitric-zinc aqueous solution was applied over each wart utilizing a 30 µL capillary tube until a whitening response was observed. Additional applications as needed were accomplished at 2-week intervals until the wart was gone. In those with hand, plantar, and subungual warts, there was a 100% clearance after two to three sessions. Three with external genital warts had only a partial response and one no benefit after four applications. Thus, this approach was effective in external genital and other "difficult-to-treat" warts in 90% of patients after one to four applications. It also was easy to use with no adverse events noted.


Assuntos
Ácidos não Carboxílicos/administração & dosagem , Ácidos Carboxílicos/administração & dosagem , Condiloma Acuminado/tratamento farmacológico , Fármacos Dermatológicos/administração & dosagem , Dermatoses do Pé/tratamento farmacológico , Dermatoses da Mão/tratamento farmacológico , Verrugas/tratamento farmacológico , Ácidos não Carboxílicos/efeitos adversos , Administração Cutânea , Ácidos Carboxílicos/efeitos adversos , Condiloma Acuminado/diagnóstico , Condiloma Acuminado/virologia , Fármacos Dermatológicos/efeitos adversos , Esquema de Medicação , Composição de Medicamentos , Dermatoses do Pé/diagnóstico , Dermatoses do Pé/virologia , Dermatoses da Mão/diagnóstico , Dermatoses da Mão/virologia , Humanos , Indução de Remissão , Fatores de Tempo , Resultado do Tratamento , Verrugas/diagnóstico , Verrugas/virologia
5.
ChemSusChem ; 9(18): 2656-2665, 2016 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-27628708

RESUMO

Although reactive additives have been employed in perovskite solar cells to enhance film morphology and significantly increase device performance, little is known about the effect of these additives on perovskite structural and optical properties. Here we report a systematic study of how the properties of methylammonium lead iodide perovskite (CH3 NH3 PbI3 ) are influenced by hydrohalic acid additives (HX; X=I, Br, Cl) in the precursor solution. Detailed structural and optical spectroscopic analysis reveals that all three acids affect the optical properties and alter the unit cell lattice parameters. Depending on the identity and concentration of HX, optical bandgaps widen or compress: addition of HBr yields a wider bandgap, whereas HI compresses the gap at high concentrations; HCl, on the other hand, has no significant effect on the bandgap. These changes can be understood by correlating them with the types of defects present in polycrystalline perovskite thin films in combination with the structural strain induced in very small crystallites. The presence of extra halides from HX in the precursor solution enables filling of the lattice vacancies in the perovskite, thereby altering metal-halogen-metal bond connectivity and consequently cell volumes and optical bandgaps. Remarkably, a room temperature tetragonal→cubic phase transition is observed for CH3 NH3 PbI3 films treated with high HX concentrations. Further insights into this anomalous phase transformation are obtained from in situ variable-temperature X-ray diffraction in the 25-55 °C (298-328 K) range, revealing a monotonic fall in transition temperature with increasing precursor solution HX concentration.


Assuntos
Ácidos não Carboxílicos/química , Iodetos/química , Chumbo/química , Metilaminas/química , Transição de Fase , Temperatura , Modelos Moleculares , Conformação Molecular , Fenômenos Ópticos
6.
Shokuhin Eiseigaku Zasshi ; 56(6): 256-62, 2015.
Artigo em Japonês | MEDLINE | ID: mdl-26699274

RESUMO

We developed and evaluated methods of quantifying cyanide (cyanide ion and cyanogen chloride) and bromic acid in mineral waters (MW). After performance evaluation, recovery studies were performed on 110 kinds of MW products to examine the applicability of the methods. The approximate proportion of the MW samples, in which the recovery rate of these anionic compounds was within 90 to 110%, was 95% in the cyanide ion and bromic acid analysis and 45% in the cyanogen chloride analysis. We observed low rates of recovery of cyanogen chloride from some MW products with pH values around neutral. To increase the recovery rate, we propose adding phosphoric acid buffer to adjust the pH of these MW samples. The retention times for bromic acid in some MW products differed from that in standard solution. We concluded that carbonic acid influences the retention times. It may be necessary to to exclude carbon dioxide from the MW samples by degassing to synchronize the retention times of bromic acid in the MW samples and the standard solution.


Assuntos
Ácidos não Carboxílicos/análise , Cromatografia por Troca Iônica/métodos , Cianetos/análise , Águas Minerais/análise , Qualidade da Água , Tampões (Química) , Dióxido de Carbono , Ácido Carbônico , Concentração de Íons de Hidrogênio , Ácidos Fosfóricos
7.
J Phys Chem A ; 119(45): 11076-83, 2015 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-26473634

RESUMO

The kinetics of the reaction of OH radicals with p-cymene has been studied in the temperature range of 243-898 K using a flow reactor combined with a quadrupole mass spectrometer: OH + p-cymene → products. The reaction rate constant was determined as a result of absolute measurements, from OH decay kinetics in excess of p-cymene and employing the relative rate method with OH reactions with n-pentane, n-heptane,1,3-dioxane, HBr, and Br2 as the reference ones. For the rate coefficient of the H atom abstraction channel, the expression k1b = (3.70 ± 0.42) × 10(-11) exp[-(772 ± 72)/T] was obtained over the temperature range of 381-898 K. The total rate constant (addition + abstraction) determined at T = 243-320 K was k1 = (1.82 ± 0.48) × 10(-12) exp[(607 ± 70)/T] or, in a biexponential form, k1 = k1a + k1b = 3.7 × 10(-11) exp(-772/T) + 6.3 × 10(-13) exp(856/T), independent of the pressure between 1 and 5 Torr of helium. In addition, our results indicate that the reaction pathway involving alkyl radical elimination upon initial addition of OH to p-cymene is most probably unimportant.


Assuntos
Gases/química , Radical Hidroxila/química , Monoterpenos/química , Temperatura , Ácidos não Carboxílicos/química , Ácidos Bóricos/química , Cimenos , Hélio/química , Heptanos/química , Ácido Bromídrico/química , Hidrogênio/química , Cinética , Espectrometria de Massas , Pentanos/química , Pressão
8.
Artigo em Chinês | MEDLINE | ID: mdl-25533373

RESUMO

OBJECTIVE: To establish a method for determination of a variety of acid gas in the workplace air by Ion Chromatography. (hydrofluoric acid, hydrogen chloride or hydrochloric acid, sulfur anhydride or sulfuric acid, phosphoric acid, oxalic acid). METHOD: The sample in workplace air was collected by the porous glass plate absorption tube containing 5 ml leacheate. (Sulfuric acid fog, phosphoric acid aerosol microporous membrane after collection, eluted with 5 ml of eluent.) To separated by AS14+AG14 chromatography column, by carbonate (2.0+1.0) mmol/L (Na(2)CO(3)-NaHCO(3)) as eluent, flow rate of 1 ml/min, then analyzed by electrical conductivity detector. The retain time was used for qualitative and the peak area was used for quantitation. RESULTS: The each ion of a variety of acid gas in the air of workplace were excellent in carbonate eluent separation. The linear range of working curve of 0∼20 mg/L. The correlation coefficient r>0.999; lower detection limit of 3.6∼115 µg/L; quantitative limit of 0.012∼0.53 mg/L; acquisition of 15L air were measured, the minimum detection concentration is 0.004 0∼0.13 mg/m(3). The recovery rate is 99.7%∼101.1%. In the sample without mutual interference ions. Samples stored at room temperature for 7 days. CONCLUSION: The same analysis method, the detection of various acidic gases in the air of workplace, simple operation, good separation effect, high sensitivity, high detection efficiency, easy popularization and application.


Assuntos
Ácidos não Carboxílicos/análise , Poluentes Ocupacionais do Ar/análise , Cromatografia/métodos , Ar/análise , Gases , Ácido Clorídrico , Ácido Fluorídrico , Íons/análise , Limite de Detecção , Ácidos Fosfóricos , Ácidos Sulfúricos , Local de Trabalho
9.
Chem Commun (Camb) ; 50(51): 6748-50, 2014 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-24831187

RESUMO

In the presence of Keggin-type phosphovanadomolybdic acids, e.g., H6PV3Mo9O40, oxidative dimerization of various kinds of primary thioamides including aromatic, heterocyclic, and aliphatic ones efficiently proceeded to give the corresponding 3,5-disubstituted 1,2,4-thiadiazoles in excellent yields.


Assuntos
Ácidos não Carboxílicos/química , Tiadiazóis/síntese química , Tioamidas/síntese química , Aerobiose , Catálise , Dimerização , Compostos Heterocíclicos/síntese química , Indicadores e Reagentes , Molibdênio/química , Oxirredução , Compostos de Fósforo/química , Espectrometria de Massas por Ionização por Electrospray , Tiadiazóis/química , Tioamidas/química , Compostos de Vanádio/química
10.
J Agric Food Chem ; 61(39): 9393-400, 2013 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-24016229

RESUMO

Wheat gluten can be converted into rigid biobased materials by high-temperature compression molding at low moisture contents. During molding, a cross-linked protein network is formed. This study investigated the effect of mixing gluten with acid/alkali in 70% ethanol at ambient temperature for 16 h followed by ethanol removal, freeze-drying, and compression molding at 130 and 150 °C on network formation and on types of cross-links formed. Alkaline pretreatment (0-100 mmol/L sodium hydroxide or 25 mmol/L potassium hydroxide) strongly affected gluten cross-linking, whereas acid pretreatment (0-25 mmol/L sulfuric acid or 25 mmol/L hydrochloric acid) had limited effect on the gluten network. Molded alkaline-treated gluten showed enhanced cross-linking but also degradation when treated with high alkali concentrations, whereas acid treatment reduced gluten cross-linking. ß-Elimination of cystine and lanthionine formation occurred more pronouncedly at higher alkali concentrations. In contrast, formation of disulfide and nondisulfide cross-links during molding was hindered in acid-pretreated gluten. Bioplastic strength was higher for alkali than for acid-pretreated samples, whereas the flexural modulus was only slightly affected by either alkaline or acid pretreatment. Apparently, the ratio of disulfide to nondisulfide cross-links did not affect the mechanical properties of rigid gluten materials.


Assuntos
Ácidos não Carboxílicos/química , Plásticos Biodegradáveis/química , Glutens/química , Hidróxidos/química , Indicadores e Reagentes/química , Sementes/química , Triticum/química , Fenômenos Químicos , Módulo de Elasticidade/efeitos dos fármacos , Temperatura Alta , Ácido Clorídrico/química , Fenômenos Mecânicos , Concentração Osmolar , Compostos de Potássio/química , Conformação Proteica , Hidróxido de Sódio/química , Solubilidade , Ácidos Sulfúricos/química
11.
Plant Physiol Biochem ; 64: 41-51, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23353765

RESUMO

To study whether differential responses occur in photosynthesis and antioxidant system for seedlings of Liquidambar formosana, an acid rain (AR)-sensitive tree species and Schima superba, an AR-tolerant tree species treated with three types of pH 3.0 simulated AR (SiAR) including sulfuric-rich (S-SiAR), nitric-rich (N-SiAR), sulfate and nitrate mixed (SN-SiAR), we investigated the changes of leaf necrosis, chlorophyll content, soluble protein and proline content, photosynthesis and chlorophyll fluorescence characteristics, reactive oxygen species production, membrane lipid peroxidation, small molecular antioxidant content, antioxidant enzyme activities and related protein expressions. Our results showed that SiAR significantly caused leaf necrosis, inhibited photosynthesis, induced superoxide radical and hydrogen peroxide generation, aggravated membrane lipid peroxidation, changed antioxidant enzyme activities, modified related protein expressions such as Cu/Zn superoxide dismutase (SOD), l-ascorbate peroxidase (APX, EC 1. 11. 1. 11), glutathione S transferase (GST, EC 2. 5. 1. 18) and Rubisco large subunit (RuBISCO LSU), altered non-protein thiols (NPT) and glutathione (GSH) content in leaves of L. formosana and S. superba. Taken together, we concluded that the damages caused by SiAR in L. formosana were more severe and suffered from more negative impacts than in S. superba. S-SiAR induced more serious damages for the plants than did SN-SiAR and N-SiAR.


Assuntos
Chuva Ácida/efeitos adversos , Ácidos não Carboxílicos/efeitos adversos , Antioxidantes/metabolismo , Liquidambar/fisiologia , Fotossíntese , Estresse Fisiológico , Theaceae/fisiologia , Membrana Celular , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Liquidambar/metabolismo , Ácido Nítrico/efeitos adversos , Folhas de Planta , Ribulose-Bifosfato Carboxilase/metabolismo , Plântula , Compostos de Sulfidrila/metabolismo , Ácidos Sulfúricos/efeitos adversos , Superóxidos/metabolismo , Theaceae/metabolismo , Árvores
12.
Anal Sci ; 29(1): 165-8, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23303105

RESUMO

During the summer of 2011 and winter of 2012, we continuously measured trace acid gas concentrations in Tokushima, Japan, using a parallel plate wet denuder coupled ion chromatograph. The average concentrations of hydrochloric acid (HCl), nitrous acid (HONO), nitric acid (HNO(3)), and sulfur dioxide (SO(2)) were, respectively, 0.54, 1.20, 1.17, and 3.22 µg m(-3) in the summer, and 0.09, 1.06, 0.46, and 5.11 µg m(-3) in the winter. In the summer, concentrations of all the acid gases increased after sunrise and showed a strong diurnal pattern with daytime maxima and nighttime minima, but the time at which concentration levels began to increase and the pace of increase differed among the acid gases. The concentration of HONO increased sharply immediately after sunrise, while concentrations of the other three gases began increasing about one and half hours later. SO(2) showed the fastest rate of increase, followed by HNO(3) and HCl. These differences were likely attributable to the formation processes of gaseous substances.


Assuntos
Ácidos não Carboxílicos/análise , Poluentes Atmosféricos/análise , Ar , Cromatografia/instrumentação , Monitoramento Ambiental/métodos , Gases/análise , Ar/análise , Ar/normas , Cromatografia/métodos , Monitoramento Ambiental/instrumentação , Ácido Clorídrico/análise , Japão , Ácido Nítrico/análise , Ácido Nitroso/análise , Estações do Ano , Dióxido de Enxofre/análise
13.
Bioresour Technol ; 130: 45-51, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23306111

RESUMO

The synthesis of bioadditives for biofuels from glycerol esterification with acetic acid was performed over zirconia supported heteropolyacids catalysts using H(4)SiW(12)O(40) (HSiW), H(3)PW(12)O(40) (HPW) and H(3)PMo(12)O(40) (HPMo) as active compounds. The as-prepared catalysts were characterized by N(2)-physisorption, XRD, Raman spectroscopy, NH(3)-TPD, FTIR of pyridine adsorption and H(2)O-TPD. Among the catalysts tested, HSiW/ZrO(2) achieved the best catalytic performance owing to the better combination of surface Brønsted acid sites and hydrothermal stability. A 93.6% combined selectivity of glyceryl diacetate and glyceryl triacetate with complete glycerol conversion was obtained at 120°C and 4h of reaction time in the presence of HSiW/ZrO(2). This catalyst also presented consistent activity for four consecutive reaction cycles, while HPW/ZrO(2) and HPMo/ZrO(2) exhibited distinct deactivation after reusability tests. In addition, HSiW/ZrO(2) can be resistant to the impurities present in bulk glycerol.


Assuntos
Ácidos não Carboxílicos/química , Diglicerídeos/síntese química , Glicerol/química , Óxidos/química , Compostos de Fósforo/química , Triacetina/síntese química , Compostos de Tungstênio/química , Ácido Acético , Biocombustíveis , Catálise , Esterificação , Temperatura , Zircônio
14.
ChemSusChem ; 6(1): 199-208, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23307750

RESUMO

The catalytic valorization of cellulose is currently subject of intense research. Isosorbide is among the most interesting products that can be formed from cellulose as it is a potential platform molecule and can be used for the synthesis of a wide range of pharmaceuticals, chemicals, and polymers. A promising direct route from cellulose to isosorbide is presented in this work. The strategy relies on a one-pot bifunctional catalytic concept, combining heteropoly acids, viz. H(4)SiW(12)O(40), and redox catalysts, viz. commercial Ru on carbon, under H(2) pressure. Starting from pure microcrystalline cellulose, a rapid conversion was observed, resulting in over 50% isosorbide yield. The robustness of the developed system is evidenced by the conversion of a range of impure cellulose pulps obtained by organosolv fractionation, with isosorbide yields up to 63%. Results were compared with other (ligno)cellulose feedstocks, highlighting the importance of fractionation and purification to increase reactivity and convertibility of the cellulose feedstock.


Assuntos
Ácidos não Carboxílicos/química , Carbono/química , Celulose/química , Isossorbida/química , Lignina/química , Rutênio/química , Sorbitol/química
15.
Bioresour Technol ; 130: 522-8, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23334006

RESUMO

The catalytic performance and recoverability of several homogeneous acid catalysts (hydrochloric, sulfuric, and nitric acids) for the esterification of enzyme-hydrolyzed free fatty acid (FFA) and methanol were studied. Although all tested catalysts drove the reaction to a high yield, hydrochloric acid was the only catalyst that could be considerably recovered and reused. The kinetics of the esterification reaction catalyzed by hydrochloric acid was investigated under varying catalyst loading (0.1-1M), reaction temperature (303-343K), and methanol/FFA molar ratio (1:1-20:1). In addition, a pseudo-homogeneous kinetic model incorporating the above factors was developed. A good agreement (r(2)=0.98) between the experimental and calculated data was obtained, thus proving the reliability of the model. Furthermore, the reusability of hydrochloric acid in FFA esterification can be predicted by the developed model. The recoverable hydrochloric acid achieved high yields of FFA esterification within five times of reuse.


Assuntos
Ácidos não Carboxílicos/química , Biocombustíveis , Ácidos Graxos não Esterificados/química , Ácidos não Carboxílicos/isolamento & purificação , Catálise , Esterificação , Ácidos Graxos não Esterificados/metabolismo , Cinética , Metanol/química , Modelos Químicos , Temperatura
16.
J Hazard Mater ; 235-236: 279-85, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-22951225

RESUMO

Impregnated activated carbons (IACs) that are used in multi-gas respirator applications usually contain copper and/or zinc impregnants. Co-impregnating with properly selected acids can improve the distribution of the metallic impregnant on the carbon and improve the gas adsorption capacity of the IAC. In this work a comparative study of some common acids co-impregnated with a zinc nitrate (Zn(NO(3))(2)) precursor is performed. The IACs were heated in an inert atmosphere at temperatures which promoted the thermal decomposition of Zn(NO(3))(2) to zinc oxide (ZnO). The gas adsorption properties of the IACs were tested using ammonia (NH(3)), sulphur dioxide (SO(2)) and hydrogen cyanide (HCN) challenge gases. Powder X-ray diffraction (XRD) was used to identify the impregnant species present after heating and to study impregnant distribution. Gravimetric analysis was used to determine the impregnant loading, and help to identify the impregnant species after heating. The interactions between the co-impregnated acid and Zn(NO(3))(2) precursor during heating are discussed. The relationship between impregnant species and gas adsorption capacity is discussed.


Assuntos
Ácido Acético/química , Ácidos não Carboxílicos/química , Carbono/química , Nitratos/química , Dispositivos de Proteção Respiratória , Tartaratos/química , Compostos de Zinco/química , Adsorção , Óxido de Zinco/química
17.
Mol Pharmacol ; 82(5): 814-23, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22851716

RESUMO

Several basic leucine zipper (B-ZIP) transcription factors have been implicated in cancer, substance abuse, and other pathological conditions. We previously identified arylstibonic acids that bind to B-ZIP proteins and inhibit their interaction with DNA. In this study, we used electrophoretic mobility shift assay to analyze 46 arylstibonic acids for their activity to disrupt the DNA binding of three B-ZIP [CCAAT/enhancer-binding protein α, cyclic AMP-response element-binding protein (CREB), and vitellogenin gene-binding protein (VBP)] and two basic helix-loop-helix leucine zipper (B-HLH-ZIP) [USF (upstream stimulating factor) and Mitf] proteins. Twenty-five arylstibonic acids showed activity at micromolar concentrations. The most active compound, P6981 [2-(3-stibonophenyl)malonic acid], had half-maximal inhibition at ~5 nM for CREB. Circular dichroism thermal denaturation studies indicated that P6981 binds both the B-ZIP domain and the leucine zipper. The crystal structure of an arylstibonic acid, NSC13778, bound to the VBP leucine zipper identified electrostatic interactions between both the stibonic and carboxylic acid groups of NSC13778 [(E)-3-(3-stibonophenyl)acrylic acid] and arginine side chains of VBP, which is also involved in interhelical salt bridges in the leucine zipper. P6981 induced GFP-B-ZIP chimeric proteins to partially localize to the cytoplasm, demonstrating that it is active in cells. P6981 inhibited the growth of a patient-derived clear cell sarcoma cell line whose oncogenic potential is driven by a chimeric protein EWS-ATF1 (Ewing's sarcoma protein-activating transcription factor 1), which contains the DNA binding domain of ATF1, a B-ZIP protein. NSC13778 inhibited the growth of xenografted clear cell sarcoma, and no toxicity was observed. These experiments suggest that antimony containing arylstibonic acids are promising leads for suppression of DNA binding activities of B-ZIP and B-HLH-ZIP transcription factors.


Assuntos
Ácidos não Carboxílicos/farmacologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/antagonistas & inibidores , DNA/metabolismo , Compostos Organometálicos/farmacologia , Ácidos não Carboxílicos/química , Animais , Antimônio/química , Fatores de Transcrição de Zíper de Leucina Básica/antagonistas & inibidores , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Proteína alfa Estimuladora de Ligação a CCAAT/antagonistas & inibidores , Pontos de Checagem do Ciclo Celular , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cinamatos/química , Dicroísmo Circular , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Zíper de Leucina , Camundongos , Camundongos SCID , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/química , Desnaturação Proteica , Transplante Heterólogo , Vitelogeninas/genética
18.
Molecules ; 17(8): 8968-81, 2012 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-22842642

RESUMO

Dry matter, organic acids, ascorbic acid, minerals (nitrogen, phosphorus, potassium, calcium, magnesium, sodium) and polyphenolic profile of a number of non-traditional fruit species and their genotypes, namely blue honeysuckle (Lonicera spp.), Saskatoon berry (Amelanchier alnifolia), black mulberry (Morus nigra), Tomentosa cherry (Prunus tomentosa Thunb.) and jostaberry (Ribes nigrum x Grossularia uva-crispa) were investigated. The results showed that Lonicera genotypes displayed high levels of ascorbic acid and they were rich in minerals, with the cultivar 'Amfora' achieving the leading position in nitrogen, phosphorus and potassium content among all lesser known fruit species. Amelanchier cultivars represented a valuable source of ascorbic acid and calcium, 'Tisnovský' and 'Smoky' together with Morus nigra 'Jugoslavska' accumulated the highest level of examined polyphenolic compounds. Regular consumption of studied less common fruit species can bring health benefits so they can represent a high potential value for fruit growers and in addition they can be utilised as functional foods.


Assuntos
Frutas/química , Valor Nutritivo , Extratos Vegetais/análise , Polifenóis/análise , Ácidos não Carboxílicos/análise , Ácidos não Carboxílicos/isolamento & purificação , Ácidos Carboxílicos/análise , Ácidos Carboxílicos/isolamento & purificação , República Tcheca , Genótipo , Lonicera/química , Minerais/análise , Minerais/isolamento & purificação , Morus/química , Extratos Vegetais/isolamento & purificação , Polifenóis/isolamento & purificação , Prunus/química , Ribes/química , Rosaceae/química
19.
ChemSusChem ; 5(2): 312-9, 2012 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-22170755

RESUMO

The generation and use of the highly potent oxidising agent HOF·MeCN in a controlled single continuous flow process is described. Oxidations of amines and azides to corresponding nitrated systems by using fluorine gas, water and acetonitrile by sequential gas-liquid/liquid-liquid continuous flow procedures are reported.


Assuntos
Acetonitrilos/química , Ácidos não Carboxílicos/química , Aminas/química , Química/instrumentação , Compostos de Flúor/química , Óxidos/química , Nitrocompostos/química , Oxirredução , Fatores de Tempo
20.
J Clin Pharm Ther ; 36(1): 99-102, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21198724

RESUMO

WHAT IS KNOWN AND OBJECTIVE: The use of extemporaneously prepared admixtures of drugs must be supported by documentation of their chemical stability. The objective was to assess the physical compatibility and the chemical stability of doxofylline with phentolamine mesilate in 0.9% sodium chloride or 5% dextrose injection for intravenous infusion. METHODS: Total volumes of 20 and 1 mL of doxofylline solution and phentolamine mesilate solution, respectively, were added to 250 mL polyolefin bags containing 5% dextrose injection or 0.9% sodium chloride injection. Bags were stored for 24 h at 20-25 °C. Chemical compatibility was measures with high-performance liquid chromatography, and physical compatibility was determined visually. RESULTS: The samples were clear and colourless when viewed in normal fluorescent room light. The pH value and particulate content of the admixtures exhibited little change. The retentions of the initial concentration of doxofylline and phentolamine mesilate in the admixtures were within 97-105%. Doxofylline and phentolamine mesilate were stable in 5% dextrose injection or in 0.9% sodium chloride for up to 24 h at 20-25 °C. WHAT IS NEW AND CONCLUSION: Doxofylline and phentolamine mesilate mixed in both 5% dextrose injection and 0.9% sodium chloride injection in 250 mL multilayer polyolefin bags at concentrations of 0.74 mg/mL and 36.9 µg/mL, respectively, were stable for up to 24 h at 20-25 °C.


Assuntos
Antagonistas Adrenérgicos alfa/química , Broncodilatadores/química , Fentolamina/química , Teofilina/análogos & derivados , Ácidos não Carboxílicos/química , Antagonistas Adrenérgicos alfa/administração & dosagem , Antagonistas Adrenérgicos alfa/análise , Broncodilatadores/administração & dosagem , Broncodilatadores/análise , Fenômenos Químicos , Cromatografia Líquida de Alta Pressão , Combinação de Medicamentos , Composição de Medicamentos , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Glucose/química , Concentração de Íons de Hidrogênio , Infusões Intravenosas , Fentolamina/administração & dosagem , Fentolamina/análise , Cloreto de Sódio/química , Temperatura , Teofilina/administração & dosagem , Teofilina/análise , Teofilina/química
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