360 resultados para OXALATE
Resumo:
Haloperidol, an antipsychotic drug, was screened for new solid crystalline phases using high throughput crystallization in pursuit of solubility improvement. Due to the highly basic nature of the API, all the solid forms with acids were obtained in the form of salts. Eleven crystalline salts in the form of oxalate (1:1), benzoate (1:1), salicylate (1:1 and 1:2), 4-hydroxybenzoate (1:1), 4-hydroxybenzoate ethyl acetate solvate (1:1:1), 3,4-dihydroxybenzoate (1:1), 3,5-dihydroxybenzoate (1:1), mesylate (1:1), besylate (1:1), and tosylate (1:1) salt were achieved. There is an insertion of carboxylate or sulfonate anion into the hydrogen bonding pattern of haloperidol. The salts with the aliphatic carboxylic acids were found to be more prone to form salt hydrates compared with aromatic carboxylate salts. All the salts were subjected to solubility measurement in water at neutral pH. There was no direct correlation observed between the solubility of the salt and its coformer. All the salts are stable at room temperature as well as after 24 h slurry experiment except the oxalate salt, which showed an unusual phase transformation from its hydrated form to the anhydrous form. A structureproperty relationship was examined to analyze the solubility behavior of the solid forms.
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Crystals of voriconazole, an antifungal drug, are soft in nature, and this is disadvantageous during compaction studies where pressure is applied on the solid. Crystal engineering is used to make cocrystals and salts with modified mechanical properties (e.g., hardness). Cocrystals with biologically safe coformers such as fumaric acid, 4-hydroxybenzoic acid, and 4-aminobenzoic acid and salts with hydrochloric acid and oxalic acid are prepared through solvent assisted grinding. The presence (salt) or absence (cocrystal) of proton transfer in these multicomponent crystals is unambiguously confirmed with single crystal X-ray diffraction. All the cocrystals have 1:1 stoichiometry, whereas salts exhibit variable stoichiometries such as HCl salt (1:2) and oxalate salts (1:1.5 and 1:1). The nanoindentation technique was applied on single crystals of the salts and cocrystals. The salts exhibit better hardness than the drug and cocrystals in the order salts drug cocrystals. The molecular origin of this mechanical modulation is explained on the basis of slip planes in the crystal structure and relative orientations of the molecules with respect to the nanoindentation direction. The hydrochloride salt is the hardest solid in this family. This may be useful for tableting of the drug during formulation and in drug development.
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Neste trabalho estudou-se a complexação do poli(acrilato de sódio), PAS, com aminpentacianoferrato de sódio,APCF. As reações de complexação ocorreram imediatamente com a formação de uma coloração amarela com total solubilização do polímero na solução 0,032 M molar do complexo. As soluções mostraram-se estáveis por 48 h e após esse período observou-se alterações na natureza do complexo polimérico com a formação de precipitado. O UV foi usado como ferramenta de caracterização do complexo. O máximo de absorção obtido após dissolução imediata foi de 405 nm com desvio para o azul (398 nm) e um pequeno efeito hipercrômico. As amostras mantidas à temperatura ambiente por mais de 48 h deram origem a precipitados, que como a solução, absorveram com máximo de 364, 389 e 398 nm. O Complexo PAS-APCF foi também caracterizado através de FTIR por ATR e apresentou pequenas variações no espectro do material de partida (PAS). Um incremento na intensidade da deformação axial assimétrica do grupo carboxilato (1651 cm-1) e a presença do estiramento em 2055 cm-1 do grupo cianeto, diferentemente do APCF (2048 cm-1), confirmaram a formação do complexo PAS-APCF. As freqüências de absorção observadas para o complexo foram compatíveis com a presença de estruturas mono e bidentadas de complexação. As análises de TGA e DSC também foram utilizadas para a caracterização das estruturas. O estudo modelo envolvendo a complexação de sais sódicos de diácidos orgânicos de diferentes tamanhos de cadeia (oxalato, malonato, succinato, glutarato e adipato), diferentemente do PAS, promoveu um desvio para o vermelho na frequência máxima de absorção junto de um pequeno efeito hipercrômico (421 nm). Esta variação pode também ser observada quando do emprego de acetato de sódio, indicando, provavelmente, apenas a formação de estruturas monodentadas
Resumo:
Este trabalho apresenta um método para reconhecimento do padrão na biodisponibilidade do ferro, através da interação com substâncias que auxiliam a absorção como vitamina C e vitamina A e nutrientes inibidores como cálcio, fitato, oxalato, tanino e cafeína. Os dados foram obtidos através de inquérito alimentar, almoço e jantar, em crianças de 2 a 5 anos da única Creche Municipal de Paraty-RJ entre 2007 e 2008. A Análise de Componentes Principais (ACP) foi aplicada na seleção dos nutrientes e utilizou-se o Algoritmo Fuzzy C-Means (FCM) para criar os agrupamentos classificados de acordo com a biodisponibilidade do ferro. Uma análise de sensibilidade foi desenvolvida na tentativa de buscar quantidades limítrofes de cálcio a serem consumidas nas refeições. A ACP mostrou que no almoço os nutrientes que explicavam melhor a variabilidade do modelo foram ferro, vitamina C, fitato e oxalato, enquanto no jantar o cálcio se mostrou eficaz na determinação da variabilidade do modelo devido ao elevado consumo de leite e derivados. Para o almoço, a aplicação do FCM na interação dos nutrientes, notou-se que a ingestão de vitamina C foi determinante na classificação dos grupos. No jantar, a classificação de grupos foi determinada pela quantidade de ferro heme na interação com o cálcio. Na análise de sensibilidade realizada no almoço e no jantar, duas iterações do algoritmo determinaram a interferência total do cálcio na biodisponibilidade do ferro.
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A urolitíase é um problema de escala mundial, que ocorre em todas as regiões, culturas e grupos raciais. A incidência desta doença vem aumentando ao redor do mundo e dados mostram que no Brasil estima-se que são afetados 5% da população com uma taxa de recorrência de 2,5%. Conhecer a composição mineral e estrutura interna dos cálculos é um passo importante para tentar entender melhor a fisiopatologia desta doença. Quatro cálculos urinários infecciosos, íntegros de grande volume (diâmetro maior que 20 mm), sendo dois provenientes da bexiga e dois de rins, obtidos cirurgicamente no setor de urologia do Hospital Universitário Pedro Ernesto (HUPE/UERJ) foram analisados usando microtomografia (μCT) e difração de raios X por policristais (DRXP). As imagens microtomográficas foram obtidas usando tubo de raios X microfoco na estação TomoLab e radiação síncrotron (SR-μCT) na linha de Física Médica, ambos no Laboratório Síncrotron Elettra, Trieste, Itália. As medidas de DRXP foram realizadas na linha de Difração de Raios X do Laboratório Nacional de luz Síncrotron, Campinas, Brasil. Para os cálculos de bexiga foram encontradas quatro fases cristalinas: estruvita (STV), oxalato mono (COM) e dihidratado (COD) e hidroxiapatita (HAp). Nos cálculos renais foram encontrados STV e HAp, sendo predominante a primeira fase cristalina. A quantidade de material amorfo (não-cristalino) foi maior que 60% da composição das amostras. A técnica convencional utilizada foi eficaz para análise dos cálculos urinários inteiros e possibilitou a visualização de estruturas internas sem interferência de procedimentos prévios de preparação da amostra. As análises de DRXP com fonte síncrotron aliadas ao método Rietveld foram determinantes para identificação e quantificação dos minerais presentes nas varias camadas das amostras. Pode-se constatar a complementaridade entre a μCT e a DRXP para caracterização microestrutural e mineralógica de cálculos urinários humanos.
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Life cycle and population biology of a perennial halophyte Arthrocnemum indicum Willd, was studied from February 1992 to January 1993. During the 12 months, the population was exposed to great variations in soil salinity from 35 to 58 ms/cm2 and soil moisture ranging from flood to drought levels. Seasonal changes in dry weight are directly related to soil salinity stress. When salinity levels become low, the dry matter production increases. A little increase in dry weight from April to July indicates that more negative soil water potentials were limiting plant growth. Proline content increased considerably during the dry season with a corresponding increase in salinity. Water soluble oxalate did not vary much with changes in salinity.
Resumo:
The “oxidase reaction” (using p-amino-dimethyl-aniline oxalate as the reagent) has been used to distinguish oxidase-negative from oxidase-positive bacteria from the sea, when grown on membrane filters. By this means, it has been shown (a) that under conditions of stable stratification of the sea as in the tropics, a relationship exists between the percentage incidence of oxidase negative bacteria in the flora and the depth of the water; (b) that the maximum value for this percentage incidence (100) is reached at or immediately below the upper limit of the oxygen minimum layer; (c) that this percentage value (expressed as Oxⁿvalues) may be used to demonstrate the movements of water masses during upwelling. Such upwelling as indicated by theoretical findings and by temperature determinations along two transects off the west coast of Ceylon during the north east monsoon, has been confirmed by the distribution of Oxⁿvalues at these transects.
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The preventive effect of fumarate, maleate, tartrate and oxalate on the denaturation of frozen rohu actomyosin at -20°C in 0.7 M KCl for 7 weeks was examined using an in vitro test model. The rate of denaturation was followed by estimating percentage salt extractability, Ca²+ ATP-ase activity and the clearing response test. Fumarate, maleate and tartrate showed cryoprotective effect for higher concentration of pre-rigor rohu actomyosin of 10 mg/ml and 20 mg/ml. At actomyosin concentration of 6 mg/ml, maleate and tartrate showed some preventive effect whereas fumarate enhanced denaturation. Oxalate showed poor cryoprotective action. Post-rigor rohu actomyosin was preserved frozen without denaturation to a greater extent than pre-rigor actomyosin.
Resumo:
Kaolinite is a dominant clay mineral in the soils in tropical and Subtropical regions, and its dissolution has an influence on a variety of soil properties. In this work, kaolinite dissolution induced by three kinds of low-molecular-weight organic acid, i.e., citric, oxalic, and malic acids, was evaluated under far-from-equilibrium conditions. The rates of kaolinite dissolution depended on the kind and concentration of organic acids, with the sequence R-oxalate > R-citrate > R-malate. Chemical calculation showed the change in concentration of organic ligand relative to change in concentration of organic acid in suspensions of kaolinite and organic acid. The effect of organic acid on kaolinite dissolution was modeled by species of organic anionic ligand. For oxalic acid, L-oxalic(2-) and HLoxalic- jointly enhanced the dissolution of kaolinite, but for malic and citric acids, HLmalic- and H2Lcitric- made a higher contribution to the total dissolution rate of kaolinite than L-malic(2-) and L-citric(3-), respectively. For oxalic acid, the proposed model was R-Si = 1.89 x 10(-12) x [(25x)/(1+25x)] + 1.93 x 10(-12) x [(1990x(1))/(1+1990x(1))] (R-2 = 0.9763), where x and x(1) denote the concentrations of HLoxalic and L-oxalic, respectively, and x(1) = 10(-3.81) x x/[H+]. For malic acid, the model was R-Si =4.79 x 10(-12) x [(328-v)/(1+328x)] + 1.67 x 10(-13) x [(1149x(1))/(1+1149x(1))] (R-2 =0.9452), where x and x(1) denote the concentrations of HLmalic and L-malic, respectively, and x(1) = 10(-5.11) x x/[H+], and for citric acid, the model was R-Si = 4.73 x 10(-12) x [(845x)/(1+845x)] +4.68 x 10(-12) x [(2855x(1))/(1+2855x(1))] (R-2 =0.9682), where x and x(1) denote the concentrations of H2Lcitric and L-citric, respectively, and x(1) = 10(-11.16) x x/[H+](2). (c) 2005 Elsevier Inc. All rights reserved.
Resumo:
锦州湾是我国较大的浅水海湾之一,该湾西南五里河沿岸汇集数家工厂排污直接人海, 形成该湾口处的最大污染源。其西南部潮滩地段已成为我国海域污染最严重的区域之一。 本文对葫芦岛3条河流、五里河口和锦州湾水体、沉积物中As的含量、分布、形态及行为进行了系统研究。结果表明,葫芦岛的连山河和五里河未受到明显的As污染,沉积物总As含量一般低于10 mg•kg-1,河水As含量一般低于10 μg•L-1,茨山河下游紧邻葫芦岛锌厂,受到了严重的As污染,沉积物As含量达75.2 mg•kg-1。五里河口区As污染非常严重,锌厂在该区排污口处沉积物As含量高达3176.1 mg•kg-1,超过国家沉积物As标准158倍。受锌厂排污的影响锦州湾As污染也很严重,沉积物中As最高含量达到569.5 mg•kg-1。沉积物和孔隙水As含量在剖面上具有相似的变化趋势,表明孔隙水As含量主要受沉积物As含量影响。锦州湾沉积物中As主要以可交换态存在,残渣态次之,盐酸提取态最少,表明锦州湾沉积物中As的活性很强,有大量的可交换态As随时会进入上覆水体,是重要的As释放源,沉积物中大量As的释放可能会对葫芦岛和锦州湾地区生态系统造成严重的威胁。 以盐度和酸碱度作为环境影响因子进行的释放模拟实验,结果显示:不同盐度条件下,沉积物中的As均在48h左右达到最大释放量。此时,盐度为0‰的水体中As的释放量最大,而其他两种盐度的水体中As的释放量较小且二者相差不大。另外,在室温条件下,随着pH值的升高,沉积物中As的释放量逐渐增加。 通过对不同形态的单一含砷矿物的As提取效果研究得出:对于分级提取方法中吸附态砷的最佳提取条件应为1M KH2PO4 (pH5) 24h, 无定型铁氧化物上结合的砷0.2M oxalic/oxalate (pH3)避光 6h, 硫化亚铁上结合的砷,0.2M oxalic/oxalate (pH3)避光 1h。
Resumo:
对15株白腐真菌进行了以玉米秸秆为基质的初步筛选,从中获得一株选择性系数较高的菌株Y10,并对其降解玉米秸秆的情况进行了研究。结果表明,在30天的培养过程中菌株Y10对玉米秸秆降解的选择性系数都大于1,第15天选择性系数最高为3.88。对未经降解和降解过的玉米秸秆分别作了紫外光谱和红外光谱分析,结果表明,经该菌降解后玉米秸秆的化学成分发生了很大变化,且木质素的降解程度要大于纤维素的降解程度。对菌株Y10进行了ITS-5.8S rDNA序列鉴定,初步判定其为Cerrena sp.。 为了考查不同的外源添加物对菌株Y10降解玉米秸秆的影响,在以玉米秸秆为基质的固态发酵培养基中分别添加了7种金属离子、8种碳源、6种氮源。结果显示,这7种金属离子均能促进木质素的降解,并且一定浓度的某些离子明显抑制纤维素的降解;其中添加0.036%的MnSO4·H2O和0.36%的MgSO4·7H2O对纤维素降解的抑制作用比较强,降解率分别为0.96%和1.31%,木质素的选择性系数分别达到了34.40和20.17。8种碳源中除麦芽糖外都能促进木质素的降解,除微晶纤维素外都明显促进纤维素的降解。6种氮源中酒石酸铵、硫酸铵、草酸铵和氯化铵的添加都会使该菌生长变慢,而且氮源浓度越高菌丝生长越慢。外加碳源和金属离子对半纤维素降解和选择性系数的影响不大。 同时对菌株Y10在液态培养下产木质素降解酶的条件和培养基做了优化。结果表明,在初始产酶培养基中,菌株Y10的漆酶酶活在第10d达到最高,锰过氧化物酶酶活在第11d达到最高,基本上检测不到木质素过氧化物酶。菌株Y10产漆酶的最适温度为32℃,最适PH为6.0;产锰过氧化物酶的最适温度为32℃,最适PH为6.5。菌株Y10产漆酶的最佳碳源为甘露糖,最佳氮源为酒石酸铵,最适诱导剂VA浓度为3 mmol/L,最适表面活性剂TW-80浓度为1%。 利用响应面法对其产漆酶的培养基进行优化,优化后的培养基配方为葡萄糖10.00 g/L,酒石酸铵0.50 g/L,大量元素296.50 ml/L,微量元素100.00 ml/L,NTA 1.40 g/L,VA 5.00 mmol/L,吐温-80加入量为0.10%。进行了菌株Y10产漆酶的验证实验,实测酶活为5282.56 U/L,与预测酶活5162.73 U/L接近。在优化后培养基中,菌株Y10在第14 d达到生长的最高峰,第20 d时,漆酶酶活最高,为11325.00 U/L;第16 d时,锰过氧化物酶酶活最高,为30.77 U/L。 对菌株Y10的漆酶酶学性质做了初步的研究,结果显示,酶反应的最适温度为40℃-65℃,最适PH为3.0。在40℃,PH=3.0时,漆酶催化ABTS反应的米氏方程为 。 Fifteen white-rot fungi based on corn stalk were screened. One white-rot fungus Y10 with high selectivity value was obtained. The degradation of corn stalk was initially studied. The results indicated that the selectivity value was above 1 during the 30 day-cultivation and the highest was 3.88 after 15 days. The composition of untreated and treated stalk was analyzed through ultraviolet spectroscopy and infrared spectroscopy. It was found that the composition of treated stalk was greatly altered and the degree of the degradation of lignin is greater than the cellulose. Y10 was identified as Cerrena sp. by ITS -5.8S rDNA sequence analysis. The influence of metal ions, carbon sources and nitrogen sources on corn stalk degradation by white-rot fungus was studied. While all seven metal ions could promote lignin degradation, the cellulose degradation was best inhibited at certain ion concentrations. Notably, when 0.036% MnSO4·H2O and 0.36% MgSO4·7H2O were added into the medium, the cellulose degradation was restrained to the extents that the coefficients of lignin selectivity rose to 34.40 and 20.17 respectively. It was also found that all carbon sources except maltose can promote lignin degradation. The addition of carbon sources other than microcrystalline cellulose significantly promoted cellulose degradation. The addition of the nitrogen sources, ammonium tartrate, ammonium sulfate, oxalate, ammonium chloride, resulted in remarkable inhibition to mycelium growth; the larger the concentrations of nitrogen sources are, the slower the mycelium grew. The addition of carbon sources and metal ions had less impact on the degradation of hemicellulose and selectivity value. Meanwhile, we optimized the conditions and culture medium of the lignin-degrading enzyme production of strain Y10. The results showed that in the initial culture medium, the Lac activity was highest at the 10th day, the MnP activity was highest at the 11th day and the LiP could not be detected. The optimum condition of Lac was at temperature 32 and PH =6.0 and the optimum condition of MnP was at temperature 32 and PH =6.5. The optimum carbon source for Lac was seminose, the optimum nitrogen source was ammonium tartrate, the optimum content of VA was 3 mmol/L, the optimum content of TW-80 was 1%. PB and RSM were used to optimize the culture medium of laccase by white-rot fungus Y10. The optimum culture medium was consist of glucose 10.00 g/L, ammonium tartrate 0.50 g/L, macro elements 296.50 ml/L, trace elements 100.00 ml/L, NTA 1.40 g/L, VA 5.00 mmol/L, TW-80 0.10%. Under the optimal conditions, the activity of laccase was 5282.56 U/L and the experimental value agreed with the predicted value 5162.73 U/L. The biomass was highest at the 14th day, the Lac activity was highest at the 20th day, the MnP activity was highest at the 16th day. The results of the studies on the characteristics of Lac showed that the optimum temperature for Lac activity is 40℃-65℃ ; the optimum PH for Lac activity is 3.0 and under 40℃,PH=3.0, the Michaelis-menten equation of Lac catalized ABTS oxidation was .
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The novel nanoparticles, [Ru(bPY)(3)](2)SiW12O40 center dot 2H(2)O(2) were firstly synthesized and characterized by elemental analysis, IR, and TEM. The nanoparticles were used to fabricate a chemically modified carbon paste electrode (CPE) by dispersing nanoparticles and graphite powder in silicone grease. Thus-prepared CPE shows bifunctional electrocatalytic activities towards the reduction of nitrite and the oxidation of oxalate, and exhibits sensitive electrochemiluminescence (ECL).
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An electrochemiluminescence (ECL) sensor based on Ru(bpy)(3)(2+)-graphene-Nafion composite film was developed. The graphene sheet was produced by chemical conversion of graphite, and was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and Raman spectroscopy. The introduction of conductive graphene into Nafion not only greatly facilitates the electron transfer of Ru(bpy)(3)(2+), but also dramatically improves the long-term stability of the sensor by inhibiting the migration of Ru(bpy)(3)(2+) into the electrochemically inactive hydrophobic region of Nafion. The ECL sensor gives a good linear range over 1 x 10(-7) to 1 x 10(-4) M with a detection limit of 50 nM towards the determination of tripropylamine (TPA), comparable to that obtained by Nafion-CNT.
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The electrochemiluminescence (ECL) of tris(2,29-bipyridyl) ruthenium(II) [Ru(bpy)(3)(2+)] ion-exchanged in the sulfonic-functionalized MCM-41 silicas was developed with tripropylamine (TPrA) as a co-reactant in a carbon paste electrode (CPE) using a room temperature ionic liquid (IL) as a binder. The sulfonic-functionalized silicas MCM-41 were used for preparing an ECL sensor by the electrostatic interactions between Ru( bpy)(3)(2+) cations and sulfonic acid groups. We used the IL as a binder to construct the CPE (IL-CPE) to replace the traditional binder of the CPE (T-CPE)-silicone oil. The results indicated that the MCM-41-modified IL-CPE had more open structures to allow faster diffusion of Ru( bpy)(3)(2+) and that the ionic liquid also acted as a conducting bridge to connect TPrA with Ru( bpy)(3)(2+) sites immobilized in the electrode, resulting in a higher ECL intensity compared with the MCM-41-modified T-CPE. Herein, the detection limit for TPrA of the MCM-41-modified IL-CPE was 7.2 nM, which was two orders of magnitude lower than that observed at the T-CPE. When this new sensor was used in flow injection analysis (FIA), the MCM-41-modified IL-CPE ECL sensor also showed good reproducibility. Furthermore, the sensor could also be renewed easily by mechanical polishing whenever needed.