Spectrophotometric determination of arsenic in soil samples using 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol (Br-PADAP)

In this paper, a new, simple and sensitive method for arsenic determination in soil is proposed. This is based on the reduction of silver (I) and iron (III) ions by arsine followed by a complexation reaction of iron (II) with the spectrophotometric reagent Br-PADAP 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol. Arsenic determination with a Sandell's sensitivity of 3.1 10-4 cm-2, linear range from 0.1 µg ml-1 to 2.0 µg ml-1 (r560 = 0.9995), molar absorptivity of 2.45 10(5) l mol-1 cm-1 and a concentration detection limit of 1.4 ng ml-1 (3s) were obtained using a 10 ml sample volume. Selectivity was increased with the use of EDTA as a masking agent. The proposed method was applied for arsenic determination in the presence of several ions amounts in digested soil samples. The results revealed that antimony (III), mercury (II), germanium (IV), platinum (IV) interferes at all analyzed proportions. The interferences can be easily removed by the use of EDTA. Precision and accuracy obtained were satisfactory with a R.S.D. < 5 %. Recovery of arsenic in soil samples varied from 95.55 to 102.70 % with a mean of 99.63 %. These results demonstrated that the proposed method is applicable for arsenic analysis in different soil samples.

Sensitive spectrophotometric determination of lamotrigine in bulk drug and pharmaceutical formulations using bromocresol green

Two new, simple, rapid and reproducible spectrophotometric methods have been developed for the determination of lamotrigine (LMT) both in pure form and in its tablets. The first method (method A) is based on the formation of a colored ion-pair complex (1:1 drug/dye) of LMT with bromocresol green (BCG) at pH 5.02±0.01 and extraction of the complex into dichloromethane followed by the measurement of the yellow ion-pair complex at 410 nm. In the second (method B), the drug-dye ion-pair complex was dissolved in ethanolic potassium hydroxide and the resulting base form of the dye was measured at 620 nm. Beer's law was obeyed in the concentration range of 1.5-15 µg mL-1 and 0.5-5.0 µg mL-1 for method A and method B, respectively, and the corresponding molar absorptivity values are 1.6932 x 10(4) and 3.748 x 10(4) L mol-1cm-1. The Sandell sensitivity values are 0.0151 and 0.0068 µg cm-2 for method A and method B, respectively. The stoichiometry of the ion-pair complex formed between the dug and dye (1:1) was determined by Job's continuous variations method and the stability constant of the complex was also calculated. The proposed methods were applied successfully for the determination of drug in commercial tablets.

Development and validation of spectrophotometric method for the determination of DPP-4 inhibitor, sitagliptin, in its pharmaceutical preparations

A simple, sensitive and reproducible spectrophotometric method was developed for the determination of sitagliptin phosphate in bulk and in pharmaceutical formulations. The proposed method is based on condensation of the primary amino group of sitagliptin phosphate with acetyl acetone and formaldehyde producing a yellow colored product, which is measured spectrophotometrically at 430nm. The color was stable for about 1 hour. Beer's law is obeyed over a concentration range of 5-25 µg/ml. The apparent molar absorptivity and Sandell sensitivity values are 1.067 x 10(4) Lmol-1cm-1 and 0.0471 µgcm-2 respectively. All the variables were studied to optimize the reaction conditions. No interference was observed in the presence of common pharmaceutical excipients. The validity of the method was tested by analyzing sitagliptin phosphate in its pharmaceutical preparations. Good recoveries were obtained. The developed method was successfully employed for the determination of sitagliptin phosphate in various pharmaceutical preparations.

New reagents for the spectrophotometric determination of ranitidine hydrochloride

A new spectrophotometric method is proposed for the assay of ranitidine hydrochloride (RNH) in bulk drug and in its dosage forms using ceric ammonium sulphate (CAS) and two dyes, malachite (MAG) green and crystal violet (CV) as reagents. The method involves the addition of a known excess of ceric ammonium sulphate to ranitidine hydrochloride in acid medium, followed by the determination of unreacted CAS by reacting with a fixed amount of malachite green or crystal violet and measuring the absorbance at 615 or 582 nm respectively against the reagent blank. The Beer's law is obeyed in the concentration range of 0.4-8.0 µg/ ml of ranitidine hydrochloride (RNH) for RNH-MAG system and 0.2-1.6µg/ml of ranitidine hydrochloride for RNH-CV system. The molar Absorptivity, Sandell's sensitivity for each system were calculated. The method has been successfully applied to the determination of ranitidine hydrochloride in pure and dosage forms.

Effect of the concentration of inoculum and tensoactive on the efficiency of Bipolaris sorokiniana infection in wheat leaves

Techniques that result in increased pathogen infection rates by employing reduced quantities of fungal spores with sparse sporulation have been developed. Experiments under controlled environment conditions were conducted to evaluate the effect of the density of Bipolaris sorokiniana conidia on the intensity of wheat helminthosporiosis. Using a selected inoculum density, the concentration of the tensoactive (Tween 20) that promoted maximum infection by the causal agent of the disease was determined. The density of lesions and the estimated severity of the disease were quantified. The selected inoculum density was 1.5 x 10(4) spores.mL-1 plus 480 µL tensoactive.L-1 water, resulting in a disease severity that allows selecting wheat cultivars resistant to B. sorokiniana.

Boron influence on concentration of polyols and other sugars in Eucalyptus

Although the functions of the element Boron (B) in plants have not been sufficiently clarified, several hypotheses have been raised. Some of the functions attributed to this element are synthesis and transport of carbohydrates. To evaluate the effect of B on the synthesis of some polyols and sugars in Eucalyptus grandis and hybrids "urograndis", these species were submitted to situations of supply and restriction of B. The experiment was carried out in a greenhouse, arranged in a randomized block design in a 2 x 2 factorial scheme, with 5 replicates of each genotype. The B levels were provided in the form of nutrient solution. No significant difference was observed in the content of mannitol, sorbitol, myo-inositol and scyllo-inositol and sugars α-glucose and β-glucose between E. grandis and hybrids. Arabinose was the only one to present a higher content in E. grandis on restriction of B. The effect of the presence of B was very expressive, but regarding B supply, the plants showed significant increase in the synthesis of the compounds evaluated.

Combustion properties of biomass residues rich in phosphorus

Tillgången på traditionella biobränslen är begränsad och därför behöver man ta fram nya, tidigare outnyttjade biobränslen för att möta de uppställda CO2 emissionsmålen av EU och det ständigt ökande energibehovet. Under de senare åren har intresset riktats mot termisk energiutvinning ur olika restfraktioner och avfall. Vid produktion av fordonsbränsle ur biomassa är den fasta restprodukten ofta den största procesströmmen i produktionsanläggningen. En riktig hantering av restprodukterna skulle göra produktionen mera lönsam och mer ekologiskt hållbar. Ett alternativ är att genom förbränning producera elektricitet och/eller värme eftersom dessa restprodukter anses som CO2-neutrala. Målsättningen med den här avhandlingen var att studera förbränningsegenskaperna hos några fasta restprodukter som uppstår vid framställning av förnybara fordonsbränslen. De fyra undersökta materialen är rapskaka, palmkärnskaka, torkad drank och stabiliserat rötslam. I studien används ett stort urval av undersökningsmetoder, från laboratorieskala till fullskalig förbränning, för att identifiera de huvudsakliga utmaningarna förknippade med förbränning av restprodukterna i pannor med fluidiserad bäddteknik. Med hjälp av detaljerad bränslekarakterisering kunde restprodukterna konstateras vara en värdefull källa för värme- och elproduktion. Den kemiska sammansättningen av restprodukterna varierar stort jämfört med mera traditionellt använda biobränslen. En gemensam faktor för alla de studerade restprodukterna är en hög fosforhalt. På grund av de låga fosforkoncentrationerna i de traditionella biobränslena har grundämnet hittills inte ansetts spela någon större roll i askkemin. Experimenten visade nu att fosfor inte mera kan försummas då man studerar kemin i förbränningsprocesser, då allt flera fosforrika bränslen tränger in på energimarknaden.

Thermal performance and concentration of gases in facilities for pigs in semiarid region from State of Paraiba - Brazil

The study was conducted in a facility for pigs during the nursery and finishing in the town of 'Montadas', in the semiarid of the state of Paraiba, Brazil, in the rainy and dry season, aiming to evaluate the concentration of oxygen, methane, carbon monoxide and ammonia, and the bioclimatic indexes: ambient temperature (AT), relative humidity (RH) and the index of black globe temperature and humidity (IBGTH). These indexes differed significantly (P>0.05) between the periods and times. The AT in the rainy season was in the thermal comfort zone(TCZ) in most of the times in the nursery; for the finishing phase, thermal discomfort occurred; during the dry season, there was thermal comfort in the nursery phase; in the finishing phase the thermal discomfort occurred at all times. In the rainy season, the IBGTH was in TCZ; in the dry season, it was above the TCZ. The RH in the rainy period was in the TCZ; in the dry season, in most of the times, below the range of the TCZ. The concentration of gases showed no differences (P > 0.05) between periods and between the times, and the carbon monoxide, hydrogen sulfide and methane were below 1.0 ppm, and the ammonia showed a mean of 5.2 ppm. None of the analyzed gases exceeded the limits established by Brazilian and international standards for animals and workers.

Development of experimental structure and influence of high CO2 concentration in maize cro

Maize is a C4 plant that shows few or no response to high [CO2]. Thus, this study aimed to analyze the photosynthetic rate and yield of maize under high [CO2] and develop open-top chambers (OTC) to create an atmosphere enriched with CO2. The experiment was conducted between October 2008 and March 2009. The OTCs were developed in modular scheme. Measurement of photosynthetic rates, transpiration, stomata conductance, grain yield and dry matter were performed. The experimental design was randomized blocks with four replications and three treatments: P1 - plants grown in OTC with 700 ppm [CO2], P2 - plants grown in OTC with environmental [CO2], and P3 - control, cultivated in open field. The results were analyzed by ANOVA and Tukey's test (Pr< 0.05). The chambers can reduce by 25% the photosynthetically active radiation and increase the air and leaf temperatures. Plants under high [CO2] (P1) showed the highest photosynthetic rates and the lowest stomata conductance and transpiration. The total weight of grains (g) and dry mass of shoots (g) showed no increases for P1, despite their higher photosynthetic rates.

Leaf concentrations of nitrogen and phosphorus in phaseolus vulgaris l. Plants under high CO2 concentration and drought stress

This study aims to evaluate the leaf concentration of nitrogen and phosphorus correlated to the production of photoassimilates in beans plants (Phaseolus vulgaris L.) under high [CO2] and drought stress. The experiment was conducted in Viçosa (Brazil), during the period from April to July 2009, by using open-top chambers equipped with CO2 injection system. The drought stress was applied, through the irrigation suspension, during the period from flowering to maturation. The experimental design was randomized blocks in split-plot scheme with four replication, where the plots with plants grown in [CO2] of 700 mg L-1 and [CO2] environment of 380 mg L-1 and the subplots with plants with and without drought stress. The results were submitted to ANOVA and Tukey test (p < 0.05). In the plants under high [CO2] with and without drought stress, the photosynthetic rate increased by 59%, while the dry matter presented an increment of 20% in the plants under high [CO2] without drought stress. Reductions in [N] and [P] occurred in plants grown under high [CO2], resulting in greater efficiency in nitrogen use for photosynthesis. The high [CO2] increase only the total dry matter and not the total mass of grains. The drought stress reduces the dry matter and mass of grain, even at high [CO2].

Concentration of injetion solution and its effects on soil and on yield of fertirrigated banana cv. Terra Maranhão

The Fertigation is the combined application of water and nutrients to a crop. It can be adapted to all types of agricultural crops. The objective of this study was to evaluate the effect of urea concentration in irrigation water on electrical conductivity of the soil solution and saturation extract along the first cycle of banana cv. Terra Maranhão. The experiment followed a completely randomized design with six treatments and ten replications. Treatments regarded for using three urea concentrations (1.0; 2.5 and 4.0 g L-1) in irrigation water applied by two micro irrigation systems (microsprinkler and drip). Results showed that there was a linear elevation of electrical conductivity of saturation extract and soil solution with the increase on concentration of urea in the injection solution. Urea should be used under concentrations up to 2.5 g L-1 in irrigation water without causing increase on electric conductivity of soil solution and saturation extract, considering 1.1 dS m-1 as the tolerated value for the crop. Nitrate in the soil solution increased significantly with the increase of urea concentration in the injection solution. The maximum concentration of nitrate in the soil occurred for 4,0 g L-1 concentration of the injection solution.

Mudanças na apresentação clínica da gravidez molar

OBJETIVO: determinar se a apresentação clínica da mola hidatiforme tem mudado nos últimos anos (1992-1998) quando comparada a registros históricos de controle (1960-1981). MÉTODOS: foram revisadas 80 fichas de pacientes com mola hidatiforme acompanhadas entre 1960-1981 no Centro de Neoplasia Trofoblástica Gestacional da Santa Casa da Misericórdia (Rio de Janeiro Brasil) e as de 801 pacientes atendidas entre 1992-1998 no mesmo centro. Foram analisados os seguintes parâmetros: idade, número de gestações, sangramento vaginal, hiperêmese, edema dos membros inferiores, hipertensão arterial, útero grande para a idade gestacional e cistos teca-luteínicos dos ovários. Para análise estatística foram utilizados os testes do qui-quadrado e o cálculo do odds ratio (OR) com intervalo de confiança (IC) de 95%. RESULTADOS: com relação à idade, a ocorrência de mola em pacientes com menos de 15 anos ou mais de 40 foi significativamente mais freqüente no grupo II do que no grupo I; quanto ao número de gestações, a diferença entre os dois grupos só não foi significativa entre aquelas pacientes que gestavam pela terceira e quarta vez. A hipertensão arterial, foi detectada em porcentagem semelhante nos dois grupos e útero grande para a idade gestacional foi mais freqüente no grupo II (41,4 vs 31,2% - p <0,05; OR: 1,5; IC: 1,0-2,3). Todos os outros elementos clínicos foram menos freqüentes no grupo II do que no grupo I. O sangramento vaginal permaneceu o elemento clínico mais freqüente, ocorrendo em 76,9% das pacientes do grupo II e 98,7% das pacientes do grupo I (p < 0,05; OR: 0,04; IC: 0,030,04). Também foram menos freqüente no grupo II quando comparado com grupo I a hiperêmese (36,5% vs 45% - p < 0,05; OR: 0,7; IC: 0,40,9); edema (12,7% vs 20% - p < 0,05; OR: 0,5; IC: 0,30,8); e cistose ovariana (16,4 vs 41,2% - p < 0,05 OR: 0,3; IC: 0,20,4). A ultra-sonografia foi o meio diagnóstico mais comum (89,2%), e o grande responsável pelo rastreio precoce da gravidez molar. CONCLUSÃO: concluiu-se haver diminuição da sintomatologia tradicional nas pacientes com mola hidatiforme quando comparadas a controle histórico, devendo-se o fato ao diagnóstico precoce proporcionado pela ultra-sonografia.

A curva de regressão da gonadotrofina coriônica humana é útil no diagnóstico precoce da neoplasia trofoblástica gestacional pós-molar?

OBJETIVO: avaliar a utilidade da curva de regressão normal da gonadotrofina coriônica humana (hCG) no diagnóstico precoce de neoplasia trofoblástica gestacional pós-molar (NTG). MÉTODOS: estudo longitudinal, incluindo 105 pacientes com mola hidatiforme completa (MHC) acompanhadas no Centro de Doenças Trofoblásticas de Botucatu, entre 1998 e 2005. Os títulos da hCG sérica foram mensurados quinzenalmente em todas as pacientes. Curvas individuais de regressão da hCG das 105 pacientes foram estabelecidas. A comparação entre a curva de regressão normal estabelecida em nosso serviço com as curvas individuais da hCG foi usada no rastreamento e diagnóstico (platô/ascensão) de NTG. O número de semanas pós-esvaziamento quando a hCG excedeu o limite normal foi comparado com o número semanas em que a hCG apresentou platô/ascensão. RESULTADOS: das 105 pacientes com MHC, 80 apresentaram remissão espontânea (RE) e 25 desenvolveram NTG. Das 80 pacientes com RE, 7 (8,7%) apresentaram, inicialmente, dosagem da hCG acima do normal, mas, no devido tempo, alcançaram a remissão. Todas as 25 pacientes com NTG apresentaram desvio da curva normal da hCG em 3,8±2,5 semanas e mostraram platô ou ascensão em 8,4±2,9 semanas (p<0,001). CONCLUSÕES: a curva de regressão normal da hCG pós-molar pode ser útil para diagnóstico de NTG.

Risco da ocorrência de neoplasia trofoblástica gestacional após a normalização da gonadotrofina coriônica humana no seguimento pós-molar

Dissertação apresentada ao Curso de Mestrado Profissional em Saúde Materno-Infantil da Universidade Federal Fluminense, como requisito para obtenção do grau de Mestre em Saúde Materno-Infantil. Área de Concentração: Saúde da Mulher e da Criança, em 16 de maio de 2014.OBJETIVO: avaliar o risco da ocorrência de neoplasia trofoblástica gestacional (NTG) após a normalização da gonadotrofina coriônica humana (hCG) no seguimento pós-molar. PACIENTES E MÉTODOS: trata-se de estudo retrospectivo, tipo coorte não concorrente, colaborativo interinstitucional, realizado nos Centros de Referência em Doença Trofoblástica Gestacional da SCMRJ, HUAP-UFF, ME-UFRJ, HC-UNESP e HC-UFG. Foram analisados dos prontuários médicos de pacientes acompanhadas nesses Serviços, entre os anos de 2002 e 2013. Esse projeto foi aprovado pelo Comitê de Ética em Pesquisa. RESULTADOS: entre as pacientes que cursaram com remissão espontânea, 10 (0,4% - 1 em cada 201 casos de MH) evoluíram com NTG após a normalização de hCG (p<0,0001; IC95% 0,2–0,7). Quando se analisa o risco de NTG após a normalização de hCG nos diferentes tipos de gravidez molar, observou-se sua ocorrência em 9/2016 (0,4% - 1 em cada 224 casos) dentre as pacientes com mola hidatiforme completa - MHC (p<0,0001; IC95% 0,2–0,7), de 1/982 (0,1% - 1 em cada 985 casos) dentre as pacientes com mola hidatiforme parcial - MHP (p<0,0001; IC95% 0,02–0,5) e em nenhuma das pacientes com gravidez molar gemelar - GMG. Consoante o tempo de normalização de hCG, a ocorrência de NTG foi observada em 1/1595 (0,06% - 1 em cada 1595 casos de MH) das pacientes cujo hCG normalizou com menos de 56 dias (p<0,0001; IC95% 0,01–0,3), enquanto que entre aquelas cujo hCG normalizou com mais de 56 dias a NTG ocorreu em 9/1416 (0,6% - 1 em cada 157 casos de MH) das pacientes (p<0,0001; IC95% 0,3–1,1), exibindo um OR de 10,19 (p=0,02; IC95% 1,29–80,58). CONCLUSÕES: o risco de NTG após a normalização de hCG é ínfimo. Parece-nos razoável que seja dada alta para a paciente com MHP após a primeira dosagem normal de hCG. Nos casos de MHC e GMG, esse seguimento deve ser mantido por 6 meses.