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1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
Mol Divers ; 14(4): 635-41, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19866367

RESUMO

Heteropolyacid H(6)P(2)W(18)O(62)·24H(2)O (WD) supported on silica (WD/SiO(2)) has been used as an effective catalytic system for the synthesis of various 1,2,4,5-tetrasubstituted imidazoles by four-component condensation of benzil, aldehydes, amines and ammonium acetate under solvent-free conditions. This approach can be useful for three-component synthesis of 2,4,5-trisubstituted imidazoles. The same reactions were repeated by using benzoin instead of benzil.


Assuntos
Ácidos não Carboxílicos/farmacologia , Imidazóis/síntese química , Polímeros/farmacologia , Dióxido de Silício/química , Compostos de Tungstênio/farmacologia , Ácidos não Carboxílicos/química , Aldeídos/síntese química , Catálise/efeitos dos fármacos , Química Farmacêutica/métodos , Eficiência , Imidazóis/química , Modelos Biológicos , Estrutura Molecular , Polímeros/química , Solventes , Espectrofotometria Infravermelho , Compostos de Tungstênio/química
8.
Nanotechnology ; 20(44): 445101, 2009 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-19801780

RESUMO

The hepatotoxicity of two types of multi-walled carbon nanotubes (MWCNTs), acid-oxidized MWCNTs (O-MWCNTs) and Tween-80-dispersed MWCNTs (T-MWCNTs), were investigated with Kunming mice exposed to 10 and 60 mg kg(-1) by intravenous injection for 15 and 60 d. Compared with the PBS group, the body-weight gain of the mice decreased and the level of total bilirubin and aspartate aminotransferase increased in the MWCNT-exposed group with a significant dose-effect relationship, while tumor necrosis factor alpha level did not show significant statistical change within 60 d. Spotty necrosis, inflammatory cell infiltration in portal region, hepatocyte mitochondria swelling and lysis were observed with a significant dose-effect relationship in the MWCNT groups. Liver damage of the T-MWCNT group was more severe than that of the O-MWCNT group according to the Roenigk classification system. Furthermore, T-MWCNTs induce slight liver oxidative damage in mice at 15 d, which was recovered at 60 d. Part of the gene expressions of mouse liver in the MWCNT groups changed compared to the PBS group, including GPCRs (G protein-coupled receptors), cholesterol biosynthesis, metabolism by cytochrome P450, natural-killer-cell-mediated cytotoxicity, TNF- alpha, NF-kappaB signaling pathway, etc. In the P450 pathway, the gene expressions of Gsta2 (down-regulated), Cyp2B19 (up-regulated) and Cyp2C50 (down-regulated) had significant changes in the MWCNT groups. These results show that a high dose of T-MWCNTs can induce hepatic toxicity in mice while O-MWCNTs seem to have less toxicity.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/patologia , Nanotubos de Carbono/toxicidade , Ácidos não Carboxílicos/química , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Comportamento Animal/efeitos dos fármacos , Bilirrubina/sangue , Peso Corporal/efeitos dos fármacos , Doença Hepática Induzida por Substâncias e Drogas/sangue , Expressão Gênica/efeitos dos fármacos , Perfilação da Expressão Gênica , Glutationa/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Oxirredução , Tamanho da Partícula , Polissorbatos/química , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Superóxido Dismutase/metabolismo , Fator de Necrose Tumoral alfa/sangue
9.
Waste Manag ; 29(7): 2033-9, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19157837

RESUMO

Associated with the rapid development of the information and electronic industry, liquid crystal displays (LCDs) have been increasingly sold as displays. However, during the discarding at their end-of-life stage, significant environmental hazards, impacts on health and a loss of resources may occur, if the scraps are not managed in an appropriate way. In order to improve the efficiency of the recovery of valuable materials from waste LCDs panel in an environmentally sound manner, this study presents a combined recycling technology process on the basis of manual dismantling and chemical treatment of LCDs. Three key processes of this technology have been studied, including the separation of LCD polarizing film by thermal shock method the removal of liquid crystals between the glass substrates by the ultrasonic cleaning, and the recovery of indium metal from glass by dissolution. The results show that valuable materials (e.g. indium) and harmful substances (e.g. liquid crystals) could be efficiently recovered or separated through above-mentioned combined technology. The optimal conditions are: (1) the peak temperature of thermal shock to separate polarizing film, ranges from 230 to 240 degrees C, where pyrolysis could be avoided; (2) the ultrasonic-assisted cleaning was most efficient at a frequency of 40 KHz (P = 40 W) and the exposure of the substrate to industrial detergents for 10 min; and (3) indium separation from glass in a mix of concentrated hydrochloric acid at 38% and nitric acid at 69% (HCl:HNO(3):H(2)O = 45:5:50, volume ratio). The indium separation process was conducted with an exposure time of 30 min at a constant temperature of 60 degrees C.


Assuntos
Resíduos Perigosos , Cristais Líquidos/análise , Gerenciamento de Resíduos/métodos , Ácidos não Carboxílicos/química , Conservação dos Recursos Naturais , Temperatura Alta , Índio/isolamento & purificação , Ultrassom
10.
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 , Soluções Tampão , Cor , Fluoresceína-5-Isotiocianato/química , Concentração de Íons de Hidrogênio , Água do Mar/análise , Espectrofotometria Ultravioleta/métodos
11.
Biochem Pharmacol ; 168: 404-411, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31386827

RESUMO

In past tellurium-based compounds had limited use, however, their therapeutic potential have been target of interest recently due to antioxidant and anti-inflammatory capabilities in experimental endotoxemia. Nevertheless, their potential hepatoprotective effect against ischemia reperfusion (IR) injury is still obscure. This study examined the possible hepatoprotective effect of telluric acid (TELL), one of tellurium-based compound, against the deteriorating effect hepatic IR injury in rats through directing toll like receptor-4 (TLR4) cascade, phosphoinositide 3-kinase(PI3K)/Akt axis, and nuclear erythroid-related factor-2 (Nrf-2) pathway as possible mechanisms contributed to TELL's effect. Indeed, male Wistar rats were randomized into 3 groups: sham-operated, control IR and TELL (50 µg/kg). TELL was administrated once daily for seven consecutive days prior to the IR induction. Pretreatment with TELL attenuated hepatic IR injury as manifested by hampered plasma aminotransaminases and lactate dehydrogenase activities. Also, TELL opposed IR induced elevation in tissue expression/activity of high-mobility group box protein-1 (HMGB1), TLR4, myeloid differentiation primary-response protein 88 (MyD88), phospho-nuclear factor-kappa B p65 (p-NF-κB p65), phospho-mitogen activated protein kinasep38 (p-MAPKp38) and tumor necrosis factor-alpha (TNF-α). Moreover, TELL reduced the elevated thiobarbituric acid reactive substances along with increased both Nrf-2 and endothelial nitric oxide synthase (eNOS) protein expression, beside replenishment of hepatic reduced glutathione. In addition, TELL induced obvious upregulation of p-PI3K and p-Akt protein expressions together with restoration of histopathological changes in IR injury. In conclusion, TELL purveyed conceivable novel hepatoprotective mechanisms and attenuated events associated with acute hepatic injury via inhibition of TLR4 downstream axis and activation of Nrf-2 and PI3K/Akt signaling cascades. Thus, TELL may provide a novel therapeutic potential for complications of hepatic IR injury.


Assuntos
Ácidos não Carboxílicos , Fígado , Fator 2 Relacionado a NF-E2 , Telúrio , Receptor 4 Toll-Like , Animais , Masculino , Ratos , Ácidos não Carboxílicos/química , Biomarcadores , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamação/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Hepatopatias/tratamento farmacológico , Hepatopatias/etiologia , Hepatopatias/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Projetos Piloto , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Distribuição Aleatória , Ratos Wistar , Traumatismo por Reperfusão/metabolismo , Telúrio/química , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo
12.
J Phys Chem B ; 112(9): 2671-7, 2008 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-18260659

RESUMO

Polyaniline (PANi) films were prepared by direct polymerizing deposition with four different kinds of acids as dopants or were prepared by a casting method on the surface of a polytetrafluoroethylene substrate. The properties of PANi films were characterized using atomic force microscopy, electrical conductivity measurements, and water contact angle measurements. Unlike the casting PANi film, experimental results indicated that the synthesized PANi films had a similar nanostructure as that of average nanoparticles (approximate diameter of 30-50 nm). To investigate the potential usefulness of PANi films in biomedical applications, we also studied their biocompatibility through the adhesion and proliferation properties of PC-12 pheochromocytoma cells. All the films were found to be biocompatible and allowed cell attachment and proliferation. However, the synthesized films have a much higher ability for cell adhesion than the casting film. After 4 days of culture on different PANi films, the cells formed more confluent monolayers on the synthesized PANi films than on the casting films. These results demonstrate that the PANi films could be used to culture neurotic cells and that their surface architecture on the nanoscale may affect cell function such as attachment and proliferation.


Assuntos
Ácidos Acíclicos/química , Ácidos não Carboxílicos/química , Compostos de Anilina/química , Materiais Biocompatíveis/química , Nanoestruturas/química , Alicerces Teciduais/química , Compostos de Anilina/síntese química , Animais , Materiais Biocompatíveis/síntese química , Adesão Celular , Proliferação de Células , Forma Celular , Ácido Cítrico/química , Condutividade Elétrica , Ácido Clorídrico/química , Interações Hidrofóbicas e Hidrofílicas , Malatos/química , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Nanopartículas/química , Células PC12 , Tamanho da Partícula , Percloratos/química , Politetrafluoretileno/química , Ratos , Propriedades de Superfície , Molhabilidade
13.
Water Res ; 42(3): 707-13, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17709127

RESUMO

Although acidification of feed water is a common practice to prevent scaling of the sparingly soluble minerals in nanofiltration and reverse osmosis processes, the change of acidity may have a potentially adverse impact on colloidal fouling, which is another important type of fouling on the membranes. In this paper, commonly used strong and weak acids are quantitatively investigated for their effect on colloidal silica fouling with a lab-scale ultrafiltration (UF) membrane system. Experiments showed that addition of either strong or weak acids in feed water would intensify colloidal fouling. However, the strength of colloidal fouling with strong acid addition was consistently higher (12-37%) than that with weak acid addition at pH 3. The smaller increase in colloidal fouling potential observed with weak acids was attributed to the adsorption of weak acid anions on the colloidal silica surface, which kept the absolute value of zeta potential of the colloids relatively high. Consequently, the difference in colloidal fouling potential with the additions of strong and weak acids diminished at high salt concentration. The findings implied that the type of acid used in feed water acidification could have a significant impact on colloidal fouling for low-salinity waters.


Assuntos
Ácidos não Carboxílicos/química , Dióxido de Silício/química , Purificação da Água/instrumentação , Coloides , Análise de Falha de Equipamento , Concentração de Íons de Hidrogênio , Concentração Osmolar , Ultrafiltração/instrumentação , Eliminação de Resíduos Líquidos/instrumentação
14.
Bioresour Technol ; 99(9): 3737-44, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17764930

RESUMO

The kinetics of epoxidation of cottonseed oil by peroxyacetic acid generated in situ from hydrogen peroxide and glacial acetic acid in the presence of liquid inorganic acid catalysts were studied. It was possible to obtain up to 78% relative conversion to oxirane with very less oxirane cleavage by in situ technique. The rate constants for sulphuric acid catalysed epoxidation of cottonseed oil were in the range 0.39-5.4 x 10(-6)L mol(-1)s(-1) and the activation energy was found to be 11.7 kcal mol(-1). Some thermodynamic parameters such as enthalpy, entropy, and free energy of activation were determined to be of 11.0 kcal mol(-1), -51.4 cal mol(-1)K(-1) and 28.1 kcal mol(-1), respectively. The order of effectiveness of catalysts was found to be sulphuric acid>phosphoric acid>nitric acid>hydrochloric acid. Acetic acid was found to be superior to formic acid for the in situ cottonseed oil epoxidation.


Assuntos
Ácidos não Carboxílicos/farmacologia , Óleo de Sementes de Algodão/química , Compostos de Epóxi/química , Peróxido de Hidrogênio/farmacologia , Ácido Acético/química , Catálise/efeitos dos fármacos , Óxido de Etileno/química , Etilenos/química , Formiatos/química , Glicóis/química , Cinética , Oxigênio , Ácidos Sulfúricos , Temperatura , Termodinâmica , Fatores de Tempo
15.
Cutan Ocul Toxicol ; 27(2): 117-21, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18568897

RESUMO

Acute generalized exanthematous pustulosis (AGEP, toxic pustuloderma, pustular drug eruption) is a not uncommon cutaneous reaction pattern that is usually related to drug administration. The eruption is of sudden onset and appears 7-10 days after the medication is started. A 22-year-old male patient who was a student at a chemical faculty attended our outpatient clinic with a complaint of pustular eruption on his face. According to his history, the eruption started with pruritus and erythema on his chin 3 days ago and spread to his face and chest. He explained that he had performed an experiment with sulfuric acid and bromic acid and was exposed to their vapor. His dermatological examination revealed erythema and pustules on his cheeks, on his chin, above his upper lip, and on his eyebrows. He also had a few pustules on his chest. There were no ocular, mucous membrane, or pulmonary symptoms. Histopathological examination of the skin biopsy specimen revealed superficial orthokeratosis, focal subcorneal pustule formation, and perivascular chronic inflammatory cell infiltration in superficial dermis. After administration of systemic antihistamines and wet dressing topically, we observed rapid healing of the lesions. Because there was no systemic drug intake in his history, we were concerned that exposure to sulfuric acid and bromic acid vapor caused AGEP in this patient. We present this rare case to show that the vapor of chemical materials may cause AGEP or other drug eruptions.


Assuntos
Acidentes de Trabalho , Ácidos não Carboxílicos/efeitos adversos , Ácido Bromídrico/efeitos adversos , Dermatopatias Vesiculobolhosas/induzido quimicamente , Ácidos Sulfúricos/efeitos adversos , Adulto , Humanos , Laboratórios , Masculino , Pele/patologia , Dermatopatias Vesiculobolhosas/patologia
16.
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
17.
J Colloid Interface Sci ; 311(2): 368-74, 2007 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-17433353

RESUMO

The uptake rates of acids (hydrochloric acid, sulfuric acid, perchloric acid and acetic acid) by colloidal solid particles (mean diameter 0.35 microm) of DEAE (diethylaminoethyl Sephadex) resin was studied by the means of the stopped flow technique equipped with a conductivity detection. This original experimental approach allows to avoid hydrodynamics perturbations during data acquisition. For the sake of comparison NaOH uptake or K(+)/H(+) exchange by sulfonic Dowex resin particles experiments have also been performed. As stated in the literature we observed that the uptake rate limiting step is the solute diffusion in the solution layer surrounding the particles. To fit the experimental conductivity versus time curves on the basis of solutes diffusion concepts a simple mathematical equation fitting perfectly well the experimental data is proposed. The mathematical modeling of kinetic data obtained in non-stationary diffusion proposed here can substitute to the empiric pseudo-first- and -second-order models often used in environmental research.


Assuntos
Ácidos não Carboxílicos/química , Coloides/química , Resinas Sintéticas , Condutometria , Difusão , Cinética , Modelos Teóricos , Tamanho da Partícula
18.
Molecules ; 12(9): 2223-8, 2007 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-17962739

RESUMO

The catalytic oxidation of thiols to the corresponding disulfides using Preyssler's catalyst H(14)[NaP(5)W(30)O(110)] has been studied. These highly selective oxidations gave good yields of the target disulfides.


Assuntos
Ácidos não Carboxílicos/química , Ar , Solventes/química , Compostos de Sulfidrila/química , Compostos de Tungstênio/química , Catálise , Dissulfetos/química , Oxirredução , Espectrofotometria Infravermelho
19.
Ann Chim ; 97(10): 1047-64, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18153999

RESUMO

An environmentally friendly and rapid digestion procedure involving 10 mL of acid mixture (HNO3 : HCl : HF = 2:2:1) for 0.1 g of sample in closed vessel microwave digester following heating program : 250W for 10 min., hold time 2 min., 600 W for 17 min, and Ventilation time 10 min was developed. The operating parameters were varied and optimized by factorial design approach using "Steepest Ascent" method. The validity of the recommended digestion procedure were examined by analyzing several well characterized standard reference materials such as diabase (W2), basalt (BIR-1, JB-3, BHVO-1), granite (G2), gabbro (JGb-1), Mn-nodule (Nod-A-1, Nod-P-1), sediment (STSD-4, LKSD-2), limestone (KH-2), soil (SAu-1), ilmenite (IGS-31), rutile (IGS-32), Zircon (IGS-35) and titanium dioxide (SRM-154b) employing both inductively coupled plasma-atomic emission spectrometry (ICP-AES) and well known spectrophotometric method. An excellent agreement between the methods and the certified values of standard reference materials suggest that the digestion procedure can be used for quality control and allied purposes.


Assuntos
Sedimentos Geológicos/análise , Titânio/análise , Ácidos não Carboxílicos , Computadores , Água Doce , Indicadores e Reagentes , Micro-Ondas , Compostos de Silício/análise , Análise Espectral/métodos
20.
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
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