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1.
Arq. Inst. Biol ; 87: e0762018, 2020. graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1121084

RESUMO

Intoxication by dispersion of glyphosate droplets in coffee seedlings is common and, in addition to the problem of drift, there are reports of contamination of this herbicide to a nontarget plant via the rhizosphere. Hydroponics allows the comparison of the translocation of the glyphosate absorbed by the foliage or the roots and avoids the interaction with the soil, which could hamper the achievement of more accurate conclusions when it is absorbed by the root. Thus, the toxicity of glyphosate sublethal dosages in the initial growth of coffee plants in hydroponics was evaluated by applying four sublethal dosages in two different locations (solution and leaf). Fifty days after the application of the herbicide, the intoxication percentage and the growth of the coffee seedlings were evaluated. From the reduced dose of 115.2 g·ha-1 of glyphosate, height reductions, root length; number of leaves, dry mass of leaf, roots and total, leaf area, and leaf mass ratio were observed. The first two parameters were observed only in leaf application and the others via leaf and solution. The aerial part­root ratio system had an increase in herbicide sublethal dosages when applied to leaves and the ratio of leaf area and specific leaf area increased in both applications. Sublethal dosages of glyphosate applied to young coffee plants under hydroponic conditions impair their growth, and it is more accentuated with increasing doses and when the leaves, instead of the roots, absorb the herbicide.(AU)


Intoxicação por dispersão das gotas de glifosato em mudas de café são comuns, além do problema da deriva, há relatos da passagem desse herbicida para planta não alvo via rizosfera. A hidroponia possibilita comparar a translocação do glifosato absorvido pelas folhagens ou raízes e evita a interação do solo que poderia dificultar a obtenção de conclusões mais precisas quando absorvido pela raiz. Assim, a toxidade de subdoses de glifosato no crescimento inicial de plantas de café em hidroponia foi avaliada aplicando-se quatro subdoses em dois locais distintos (solução e folha). Cinquenta dias após a aplicação do herbicida, a porcentagem de intoxicação e o crescimento das mudas de café foram avaliados. A partir da subdose de 115,2 g·ha-1 de glifosato observaram-se reduções da altura; comprimento radicular; número de folhas; massa seca da folha, raiz, radicular e total; área foliar; razão de massa foliar, sendo os dois primeiros parâmetros observados somente na aplicação foliar e os demais via foliar e solução. A relação parte aérea/sistema radicular aumentaram com o incremento das subdoses do herbicida quando aplicado nas folhas e a razão de área foliar e área foliar específica aumentaram em ambas as vias de aplicação. Subdoses de glifosato aplicadas em plantas jovens de café, em condições hidropônicas, prejudicam o seu crescimento sendo mais acentuados com o aumento das doses e quando o herbicida é absorvido pelas folhas em relação à absorção radicular.(AU)


Assuntos
Café , Hidroponia , Herbicidas , Absorção , Poluição Ambiental , Toxicidade , Rizosfera
2.
Rev. odontol. UNESP (Online) ; 48: e20180128, 2019. tab
Artigo em Português | LILACS, BBO - Odontologia | ID: biblio-1014403

RESUMO

Resumo Introdução A solubilidade e sorção dos materiais restauradores são considerados fatores críticos, pois podem interferir na qualidade e durabilidade das restaurações. Objetivo Avaliar a solubilidade e sorção de água de alguns materiais restauradores. Material e método Foram confeccionados quatorze espécimes de cada um dos seguintes materiais: Equia® Forte, Z100, Fuji IX/ e Vidrion R, os quais foram levados a uma dessecadora e pesados diariamente até estabilização. Em seguida, foram inseridos em recipientes individuais contendo 40 mL de água destilada cada e divididos em dois grupos de acordo com o tempo de armazenagem: 7 ou 30 dias. Ao final de cada período, os espécimes foram retirados da água, pesados, levados à dessecadora e pesados novamente até estabilização. Os resultados foram analisados estatisticamente utilizando os testes ANOVA 2 critérios e Tukey. Resultado Com exceção do Equia® Forte e Z100, os demais materiais, apresentaram uma variação significativa da solubilidade ao longo do tempo. Quanto à sorção, observa-se que apenas o material Z100 não apresentou diferença significativa em relação ao tempo de armazenagem, mas, na comparação entre os materiais, todos apresentaram diferenças significativas em ambos os períodos. Conclusão Após os períodos de armazenagem de 7 e 30 dias em água, os materiais restauradores Equia® Forte e Z100 não apresentam variação significativa da solubilidade, sendo mais estáveis que os materiais Fuji IX e Vidrion R. Os materiais à base de ionômero de vidro, Equia® Forte, Fuji IX e Vidrion R, sofrem mais sorção em água quando comparados ao material Z100 em ambos os períodos.


Abstract Introduction The solubility and sorption parameters of restorative materials are considered critical factors since they may interfere with the quality and durability of restorations. Objective The aim of this study was to evaluate the solubility and water sorption of some restorative materials. Material and method Fourteen specimens were made (10.0 mm x 2.0 mm) of each of the following material: Equia® Forte, Z100, Fuji IX/ e Vidrion R, then taken to a desiccator and weighed daily until stabilized. They were then placed in individual containers with 40mL of distilled water each and divided into two groups according to the storage time: 7 or 30 days. At the end of each period, the specimens were removed from the water, weighed, taken to the desiccator and weighed again until stabilized. The results were analyzed statistically with two-way ANOVA and Tukey. Result Except for Equia® Forte and Z100, the other materials presented a significant variation of solubility over time. As for sorption, it was noticed that only Z100 presented no significant difference in relation to the storage time, but in comparison of the materials, all had significant differences in both 7 and 30 days periods. Conclusion After storage periods of 7 and 30 days in water, the restorative materials Equia® Forte and Z100 do not present significant variation of solubility, being more stable than the materials Fuji IX and Vidrion R. The glass ionomer-based materials, Equia® Forte, Fuji IX and Vidrion R, suffer more sorption in water when compared to Z100 material in both periods.


Assuntos
Solubilidade , Água , Restauração Dentária Permanente , Absorção , Bis-Fenol A-Glicidil Metacrilato , Tratamento Dentário Restaurador sem Trauma , Cimentos de Ionômeros de Vidro
3.
Rev. bras. ciênc. vet ; 25(1): 31-35, jan./mar. 2018. il.
Artigo em Português | LILACS | ID: biblio-987923

RESUMO

Objetivou-se caracterizar o colostro da primeira ordenha de búfalas da raça Murrah utilizando a metodologia não oficial de absorção infravermelha. Para isso, foram colhidas amostras individuais de 42 fêmeas multíparas, por meio de ordenha manual. As amostras foram coletadas em até 12 h após o parto e encaminhadas para determinação de gordura, proteína, lactose, sólidos totais e sólidos não gordurosos por meio de absorção infravermelha. Realizamos também a contagem de células somáticas (CCS) e leitura de condutividade elétrica (CE) do colostro. Os dados foram submetidos à análise estatística descritiva através do procedimento proc means. Os valores de condutividade elétrica foram divididos em quatro classes e as médias das características físico-químicas das diferentes classes foram comparadas pelo teste T com 5% de significância. Também foi realizada análise de correlação entre as características químicas, CCS e CE do colostro. Foram obtidas médias de 4,34 ± 3,24% para gordura, 11,88 ± 3,93% para proteína, 2,54 ± 0,9% para lactose, 10,01 ± 3,33% para caseína, 26,56 ± 4,18% para sólidos totais, 16,20 ± 3,70% para sólidos não gordurosos, 316,86 ± 341,56 mil células somáticas, e 4,44 ± 0,81 mS cm-1 para condutividade elétrica do colostro. O colostro de búfalas ordenhadas em até 12h pós-parto apresenta elevado teor de proteína. Além disso, observamos que quanto maior a leitura da condutividade elétrica, menores são os percentuais de proteína, caseína e sólidos não gordurosos no colostro.


The objective of this study was to characterize the colostrum of the first milking of buffaloes of the Murrah breed using the infrared absorption. For this, individual samples of 42 multiparous females were collected by manual milking. Samples were collected up to 12h after delivery and sent for determination of fat, protein, lactose, total solids and non-greasy solids by the infrared absorption method. We also performed somatic cell counts (SCC) and electric conductivity (EC) reading of colostrum. The data were submitted to descriptive statistical analysis through the procedure proc means. The values of electrical conductivity were divided into four classes and the means of physical-chemical characteristics of the different classes were compared by the T test with 5% significance. A correlation analysis was also performed between the chemical characteristics, SCC and EC of colostrum. Averages of 4.34 ± 3.24% for fat, 11.88 ± 3.93% for protein, 10.01 ± 3.33% for casein, 2.54 ± 0.9% for lactose, 26, 56 ± 4.18% for total solids, 16.20 ± 3.70% for non-greasy solids, 316.86 ± 341.56 mil somatic cells and 4.44 ± 0.81 mS cm -1 for electrical conductivity of colostrum. The colostrum of milked buffaloes up to 12 hours postpartum presents high protein content. In addition, we observed that the higher the electrical conductivity reading, the lower the percentages of protein, casein and non-greasy solids in colostrum.


Assuntos
Animais , Búfalos , Absorção
4.
Braz. J. Pharm. Sci. (Online) ; 54(3): e17498, 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-974415

RESUMO

The goal of this research was to identify major compounds of the aerial parts of M. parvifolia (Benth.) Parra-Os., that could enhance its possible application as additive in dermocosmetic products, as well as evaluate the antioxidant properties. The extracts agreed with the broad-spectrum UVB/UVA absorption detected and could act as broad-spectrum sunscreens, covering the UVA and UVB range. Methanolic extracts showed an important antiradical capacity (0.46 and 0.47 g/µmol DPPH), TPC (37.58 and 51.41mg GAE/g DS) and TAC (1.12 and 3.31 mg C3GE/g DS) in fruits and leaves, respectively. M. parvifolia could be considered as a prospective source of natural UV-radiation absorbers with antioxidant capacity. Although the results have clearly demonstrated the potential photoprotection capacity, more studies are needed to enhance its application as an additive in pharmaceutical and medicinal formulations.


Assuntos
Raios Ultravioleta/efeitos adversos , Extratos Vegetais , Myricaceae/classificação , Absorção , Protetores Solares/efeitos adversos , Técnicas In Vitro/instrumentação , Componentes Aéreos da Planta , Aditivos em Cosméticos , Antioxidantes
5.
Arq. Inst. Biol ; 84: e0072015, 2017. tab
Artigo em Português | LILACS, VETINDEX | ID: biblio-887872

RESUMO

Objetivou-se avaliar a capacidade de adsorção in vitro de aflatoxina B1 (AFB1) por produtos comerciais utilizados na alimentação animal. Muitas pesquisas estão sendo realizadas para a descontaminação de AFB1 em alimentos. Os produtos comerciais utilizados frequentemente na alimentação de peixes, disponíveis na forma de probióticos, são formados por cepas de bactérias e leveduras utilizadas na maioria dos ensaios de adsorção de micotoxinas. Foram utilizados três produtos comerciais: A, composto por Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium e Lactobacillus acidophilus; B, por leveduras secas de Saccharomyces cerevisiae provenientes de cervejaria; e C, por Bacillus subtilis, Bacillus licheniformis e Bacillus pumilus. Cinco suspensões da dose máxima recomendada pelo fabricante de cada produto (0; 25; 50; 75 e 100%) foram testadas contra AFB1 (1000 ng.mL-1) em microtubos para determinação da capacidade de adsorção. Para simular o pH do estômago e do intestino de tilápias do Nilo (Oreochromis niloticus) foram formuladas soluções tampão fosfato salino (PBS), com pH 1,5 e 7,5; respectivamente. Os microtubos foram introduzidos em uma centrífuga com agitação mecânica, a 37ºC por 1 h e depois centrifugados por 10 min a 14.000 rpm; os sobrenadantes foram quantificados por cromatografia líquida de alta eficiência. Os produtos comerciais, nas concentrações máximas, foram capazes de adsorver AFB1 em quantidades de 45,01 a 129,59; 123,90 a 215,59 e 209,98 a 370,73 ng.mL-1, respectivamente. Concluiu-se que todos os produtos comerciais analisados adsorvem AFB1 em condições simuladas de pH gastrointestinal e são candidatos potenciais para adsorção de AFB1 para futuros ensaios in vivo.(AU)


The aim of this study was to evaluate the aflatoxin B1 (AFB1) adsorption capacity, in vitro, by commercial products used in animal feed. Many studies are being conducted for the decontamination of aflatoxins in feed. The commercial products destined to fish feed that are available as probiotics and are formed by strains of bacteria and yeasts used in most mycotoxins adsorption assays. Three commercial products were studied: A, consisting of Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium and Lactobacillus acidophilus; B, consisting of dry yeast of Saccharomyces cerevisiae from brewery; and C, consisting of Bacillus subtilis, Bacillus licheniformis and Bacillus pumilus. Five suspensions of the maximum dose recommended by the manufacturer of each product (0; 25; 50; 75 and 100%) were tested against AFB1 (1000 ng.mL-1) in microtubes to determine the adsorption capacity. To simulate the pH of the stomach and intestine of the Nile tilapia (Oreochromis niloticus), phosphate buffered saline solutions (PBS) at pH 1.5 and 7.5, respectively, were formulated. Microtubes were introduced into a centrifuge with mechanical agitation at 37ºC for 1 h and then centrifuged for 10 min at 14.000 rpm; the supernatants were quantified by high-performance liquid chromatography. The commercial products in the maximum concentration were capable of adsorbing AFB1 in amounts from 45.01 to 129.59; from 123.90 to 215.59; and from 209.98 to 370.73 (ng.mL-1), respectively. It was concluded that all commercial products, which are added to animal feed, adsorbed AFB1 under simulated gastrointestinal pH conditions and are potential candidates for AFB1 adsorption for future in vivo studies.(AU)


Assuntos
Animais , Aflatoxina B1 , Ciclídeos , Ração Animal , Absorção
6.
Rev Panam Salud Publica ; 40(1),jul. 2016
Artigo em Inglês | PAHO-IRIS | ID: phr-28576

RESUMO

To improve the quality of pharmaceutical products in their markets, several Latin American countries have begun to require that new generic products demonstrate bioequivalence against innovator or reference products. However, given the number of products involved, it is not feasible to rely on clinical studies to comply with this requirement. Instead, it makes sense to adopt or develop strategies that are appropriate to the characteristics of the region. To streamline drug development and accelerate patients’ access to quality drug products, 15 years ago the United States Food and Drug Administration (FDA) decided to grant exemptions from clinical bioequivalence studies (i.e., biowaivers) for certain types of drug products based on the Biopharmaceutics Classification System (BCS). Biowaivers can significantly reduce development time and cost and can also prevent unnecessary human exposure to potentially dangerous drugs while providing a robust, consistent standard for therapeutic equivalence of generic drug products. In addition, the limited success of translating in vitro dissolution data into in vivo performance can be enhanced using innovative tools such as the in vitro dissolution and absorption systems (IDAS). By integrating in vitro dissolution and permeability tests, these systems can provide useful insights for formulation development. A thorough assessment of the potential of in vitro techniques, along with formalization of their use through regulatory science initiatives when appropriate, may lead to cost-effective tools to help address some of the quality and regulatory challenges faced in the Latin American and Caribbean region.


Para mejorar la calidad de los productos farmacéuticos comercializados en su mercado, varios países latinoamericanos han empezado a exigir que se demuestre la bioequivalencia de los nuevos medicamentos genéricos frente a los medicamentos innovadores o de referencia. Sin embargo, dado el gran número de medicamentos, resulta, poco factible realizar estudios clínicos para cumplir con este requisito pero tiene sentido incorporar o elaborar estrategias que sean acordes a las características de la región. Para simplificar el desarrollo de fármacos y optimizar el acceso de los pacientes a medicamentos de buena calidad, hace 15 años la Administración de Alimentos y Medicamentos de los Estados Unidos de América (FDA) decidió conceder exenciones a la realización de estudios clínicos de bioequivalencia (es decir, bioexenciones) a algunos tipos de medicamentos conforme al Sistema de Clasificación Biofarmacéutica. Las bioexenciones reducen significativamente el tiempo y el costo de desarrollo, y también evitan la exposición innecesaria de seres humanos a medicamentos que podrían ser nocivos, a la vez que constituyen una norma robusta y uniforme que garantiza la equivalencia terapéutica de los medicamentos genéricos. Por otra parte, los métodos innovadores, como los sistemas de disolución y absorción in vitro, permiten ampliar los resultados limitados obtenidos al aplicar los datos de disolución in vitro para simular los efectos in vivo. Dado que combinan las pruebas de disolución in vitro con las de permeabilidad, estos sistemas brindan conocimientos útiles para el desarrollo galénico. Es probable que la evaluación meticulosa del potencial de las técnicas in vitro, junto con su formalización mediante iniciativas de normalización científica cuando corresponda, permita concebir métodos eficaces en función de los costos que ayuden a encarar algunos de los retos relativos a la calidad y la regulación de los medicamentos que enfrentan América Latina y el Caribe.


Assuntos
Biofarmácia , Dissolução , Permeabilidade , Absorção , Equivalência Terapêutica , Controle de Qualidade , Biofarmácia , Dissolução , Permeabilidade , Absorção , Equivalência Terapêutica , Controle de Qualidade
7.
Arch. latinoam. nutr ; 66(2): 87-100, June 2016. ilus, tab
Artigo em Inglês | LILACS, LIVECS | ID: lil-785928

RESUMO

Phenolic compounds are ubiquitous in plant-based foods. High dietary intake of fruits, vegetables and cereals are related to a decreased rate in chronic diseases. Phenolic compounds are thought to be responsible, at least in part, for those health effects. Nonetheless, the bioaccessibility of phenolic compounds is not often considered in these studies; thus, a precise mechanism of action of phenolic compounds is not known. In this review, we aim to present a comprehensive knowledge of the potential health promotion effects of polyphenols and the importance of considering the factors that affect their bioavailability on research projects(AU)


Los compuestos fenólicos son ubicuos en alimentos de origen vegetal. La alta ingesta de frutas, vegetales y cereales está relacionada con un bajo índice en padecimientos crónicos. Se cree que los compuestos fenólicos son, en parte, responsables de este efecto benéfico. Sin embargo, la bioaccesibilidad y biotransformación de los compuestos fenólicos generalmente no es considerada en este tipo de estudios. Por lo tanto, no se ha podido obtener un mecanismo de acción de los compuestos fenólicos. En este trabajo, presentamos una revisión de literatura del potencial benéfico de los compuestos fenólicos y cómo diversos factores pueden afectar su absorción y metabolismo(AU)


Assuntos
Humanos , Masculino , Feminino , Plantas/metabolismo , Grão Comestível/metabolismo , Compostos Fenólicos/análise , Frutas , Consumo de Alimentos , Absorção , Alimentos, Dieta e Nutrição
9.
Braz. j. pharm. sci ; 52(1): 171-178, Jan.-Mar. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-789082

RESUMO

ABSTRACT The surface of flat-sheet nylon membranes was modified using bisoxirane as the spacer and polyvinyl alcohol as the coating polymer. The amino acid histidine was explored as a ligand for endotoxins, aiming at its application for endotoxin removal from aqueous solutions. Characterization of the membrane adsorber, analysis of the depyrogenation procedures and the evaluation of endotoxin removal efficiency in static mode are discussed. Ligand density of the membranes was around 7 mg/g dry membrane, allowing removal of up to 65% of the endotoxins. The performance of the membrane adsorber prepared using nylon coated with polyvinyl alcohol and containing histidine as the ligand proved superior to other membrane adsorbers reported in the literature. The lack of endotoxin adsorption on nylon membranes without histidine confirmed that endotoxin removal was due to the presence of the ligand at the membrane surface. Modified membranes were highly stable, exhibiting a lifespan of approximately thirty months.


RESUMO A superfície de membranas planas de nylon foi modificada utilizando-se bisoxirano como espaçador e poli(álcool vinílico) para recobrimento das membranas. O aminoácido histidina foi utilizado como ligante para endotoxinas, visando à sua aplicação na remoção de endotoxinas a partir de soluções aquosas. São discutidas as etapas de caracterização do adsorvedor com membranas, análise do procedimento de despirogenização e avaliação da eficiência de remoção em modo estático. A densidade de ligantes nas membranas foi em torno de 7 mg/g membrana (massa seca), permitindo uma remoção de endotoxinas de até 65%. O desempenho das membranas preparadas com nylon e recobertas com poli(álcool vinílico) contendo histidina como ligante foi superior ao de outros adsorvedores com membranas descritos na literatura. A ausência de adsorção de endotoxinas em membranas sem histidina confirma que a remoção das endotoxinas deve-se exclusivamente à presença do ligante na superfície da membrana. As membranas modificadas mostraram-se bastante estáveis, exibindo um tempo de vida superior a 30 dias.


Assuntos
Absorção , Endotoxinas/farmacocinética , Nylons/farmacocinética , Histidina/farmacocinética
10.
Rev. chil. nutr ; 42(4): 392-398, dic. 2015. ilus
Artigo em Inglês | LILACS | ID: lil-775511

RESUMO

Iron deficiency is the most common type of nutritional deficiency in the world, and calcium intake is low in many populations. Developing a supplement that contains both micronutrients would be an excellent method to prevent iron deficiency and increase calcium intake. Human and cellular studies have shown that calcium inhibits iron absorption. Currently, the mechanisms underlying this inhibitory effect have not been elucidated. Because calcium is involved in cell signaling pathways, it may affect the regulation of the expression or localization of proteins involved in iron uptake and efflux in enterocytes. The aim of this review was to describe the processes involved in the absorption of dietary iron and the regulation of the expression and activity of proteins involved in this absorption. Additionally, the potential mechanisms by which calcium affects the expression and localization of these proteins are also discussed.


La deficiencia de hierro es la deficiencia nutricional más común en el mundo y la ingesta de calcio es baja en la mayoría de poblaciones. El desarrollo de un suplemento que contenga ambos micronutrientes sería una excelente estrategia para prevenir la deficiencia de hierro y aumentar la ingesta de calcio. Estudios en humanos y en células han demostrado que el calcio inhibe la absorción del hierro. Actualmente los mecanismos que explican este efecto inhibitorio no están claramente dilucidados. Dado que el calcio está implicado en la señalización celular, podría afectar la regulación de la expresión y localización de proteínas implicadas en la captación y eflujo de hierro en los enterocitos. El objetivo de esta revisión es describir los procesos implicados en la absorción del hierro dietario y la regulación de la expresión y actividad de las proteínas implicadas en esta absorción. Además, se discutirán los posibles mecanismos por los cuales el calcio afecta la expresión y localización de esas proteínas.


Assuntos
Deficiência de Ferro/prevenção & controle , Proteínas , Cálcio , Absorção , Ferro , Estado Nutricional
13.
Pol Merkur Lekarski ; 37(219): 181-5, 2014 Sep.
Artigo em Polonês | MEDLINE | ID: mdl-25345281

RESUMO

Along with the increasing prevalence of obesity surgical methods of treatment are becoming more accessible. The success of bariatric surgery results from the failure of conservative treatment of obesity through diet, exercises and behavioral changes. Such behaviors, including less effective drug therapy, are responsible for rather small and unstable weight reduction. In contrast, surgical treatment restrictions limiting the amount of food intake, excluding treatments and mixed treatments usually give a spectacular effect, though it is not always consistent with the previous assumptions. Most of us, however, do not realize the risk of the consequences that these treatments bring. The change of the absorption of oral medications, vitamins, microelements, often change the way they are metabolized and it forces ones to change the form of the drug, the way they are taken, which undoubtedly is associated with higher costs of later treatment. Many clinicians are unaware of the need for lifelong supplementation of some vitamins and microelements, as well as the need to modify pharmacotherapy in patients who have undergone this type of operations. This article presents examples of the best known and described changes in the absorption of drugs and micronutrients and explains how well oriented the internist ought to be when qualifying a patient to undergo this type of treatment. The described topic is interesting, but also controversial due to the fact that it corresponds closely with the surgical specialties, quite spectacular in their effects and behavioral specializations, that in many years time will be looking after the patient who underwent the surgery, but is still sick.


Assuntos
Cirurgia Bariátrica/efeitos adversos , Síndromes de Malabsorção/etiologia , Micronutrientes/farmacocinética , Obesidade Mórbida/cirurgia , Vitaminas/farmacocinética , Absorção , Humanos , Obesidade Mórbida/metabolismo
14.
Nat Mater ; 13(10): 938-46, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25194702

RESUMO

In materials showing reverse saturable absorption (RSA), the optical absorbance increases as the power of the light incident on them increases. To date, RSA has only been observed when very intense light sources, such as short-pulse lasers, are used. Here, we show that hydroxyl steroidal matrices embedding properly designed aromatic molecules as acceptors and transition-metal complexes as donors exhibit high RSA on exposure to weak incoherent light at room temperature and in air. Accumulation by photosensitization of long-lived room-temperature triplet excitons in acceptors with a large triplet-triplet absorption coefficient allows a nonlinear increase in absorbance also under low-power irradiation conditions. As a consequence, continuous exposure to weak light significantly decreases the transmittance of thin films fabricated with these compounds. These optical limiting properties may be used to protect eyes and light sensors from exposure to intense radiation generated by incoherent sources and for other light-absorption applications that have not been realized with conventional RSA materials.


Assuntos
Esteroides/química , Esteroides/efeitos da radiação , Absorção , Estradiol/química , Estradiol/efeitos da radiação , Lasers , Luz , Fenômenos Ópticos , Processos Fotoquímicos
15.
J Air Waste Manag Assoc ; 64(8): 917-26, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25185394

RESUMO

Rural and background sites provide valuable information on the concentration and optical properties of organic, elemental, and water-soluble organic carbon (OC, EC, and WSOC), which are relevant for understanding the climate forcing potential of regional atmospheric aerosols. To quantify climate- and air quality-relevant characteristics of carbonaceous aerosol in the central United States, a regional background site in central Texas was chosen for long-term measurement. Back trajectory (BT) analysis, ambient OC, EC, and WSOC concentrations and absorption parameters are reported for the first 15 months of a long-term campaign (May 2011-August 2012). BT analysis indicates consistent north-south airflow connecting central Texas to the Central Plains. Central Texas aerosols exhibited seasonal trends with increased fine particulate matter (< 2.5 microm aerodynamic diameter, PM2.5) and OC during the summer (PM2.5 = 10.9 microg m(-3) and OC = 3.0 microg m(-3)) and elevated EC during the winter (0.22 microg m(-3)). When compared to measurements in Dallas and Houston, TX, central Texas OC appears to have mixed urban and rural sources. However central Texas EC appears to be dominated by transport of urban emissions. WSOC averaged 63% of the annual OC, with little seasonal variability in this ratio. To monitor brown carbon (BrC), absorption was measured for the aqueous WSOC extracts. Light absorption coefficients for EC and BrC were highest during summer (EC MAC = 11 m2 g(-1) and BRC MAE365 = 0.15 m2 g(-1)). Results from optical analysis indicate that regional aerosol absorption is mostly due to EC with summertime peaks in BrC attenuation. This study represents the first reported values of WSOC absorption, MAE365, for the central United States. Implications: Background concentration and absorption measurements are essential in determining regional potential radiative forcing due to atmospheric aerosols. Back trajectory, chemical, and optical analysis of PM2.5 was used to determine climatic and air quality implications of urban outflow to a regional receptor site, representative of the central United States. Results indicate that central Texas organic carbon has mixed urban and rural sources, while elemental carbon is controlled by the transport of urban emissions. Analysis of aerosol absorption showed black carbon as the dominant absorber, with less brown carbon absorption than regional studies in California and the southeastern United States.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Carbono/análise , Monitoramento Ambiental , Absorção , Cidades , Filtração , Tamanho da Partícula , Material Particulado/análise , Estações do Ano , Espectrofotometria Ultravioleta , Texas
16.
Environ Sci Technol ; 48(17): 10217-26, 2014 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-25102050

RESUMO

Sources, optical properties, and chemical composition of atmospheric brown carbon (BrC) aerosol are uncertain, making it challenging to estimate its contribution to radiative forcing. Furthermore, optical properties of BrC may change significantly during its atmospheric aging. We examined the effect of photolysis on the molecular composition, mass absorption coefficient, and fluorescence of secondary organic aerosol (SOA) prepared by high-NOx photooxidation of naphthalene (NAP SOA). Our experiments were designed to model photolysis processes of NAP SOA compounds dissolved in cloud or fog droplets. Aqueous solutions of NAP SOA were observed to photobleach (i.e., lose their ability to absorb visible radiation) with an effective half-life of ∼15 h (with sun in its zenith) for the loss of near-UV (300-400 nm) absorbance. The molecular composition of NAP SOA was significantly modified by photolysis, with the average SOA formula changing from C14.1H14.5O5.1N0.085 to C11.8H14.9O4.5N0.023 after 4 h of irradiation. However, the average O/C ratio did not change significantly, suggesting that it is not a good metric for assessing the extent of photolysis-driven aging in NAP SOA (and in BrC in general). In contrast to NAP SOA, the photobleaching of BrC material produced by the reaction of limonene + ozone SOA with ammonia vapor (aged LIM/O3 SOA) was much faster, but it did not result in a significant change in average molecular composition. The characteristic absorbance of the aged LIM/O3 SOA in the 450-600 nm range decayed with an effective half-life of <0.5 h. These results emphasize the highly variable and dynamic nature of different types of atmospheric BrC.


Assuntos
Atmosfera/química , Carbono/química , Laboratórios , Fenômenos Ópticos , Luz Solar , Absorção , Aerossóis/química , Cicloexenos/química , Meia-Vida , Limoneno , Espectrometria de Massas , Peso Molecular , Naftalenos/química , Compostos Orgânicos/química , Oxirredução , Fotólise/efeitos da radiação , Soluções , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Terpenos/química
17.
Zhongguo Zhong Yao Za Zhi ; 39(9): 1709-13, 2014 May.
Artigo em Chinês | MEDLINE | ID: mdl-25095389

RESUMO

Flavonoids are a class of important active ingredients in traditional Chinese medicine, pharmacological activity and in vivo process is the focus of research in recent years. Calycosin is the main active ingredients of flavonoids in Astragali Radix, recent studies indicate that it has many kinds of pharmacological activity, but the absorption and transport characteristics in vivo is unclear. The experiment using Caco-2 cell model, with apigenin as internal standard substance, using the method for the determination of drug concentration by HPLC, were studied at different concentrations and absorption transport characteristics of respectively adding different types of protein inhibitors. Data were analyzed by Q test, the results show that low, middle, high concentration of P(app)(BL-AP)/ P(app)(AP-BL) = 1.38 < 1.5, respectively adding different types of protein inhibitors, compared with the control group of P(app)(BL-AP)/ P(app)(AP-BL), there were no significant differences. Calycosin absorption may mainly passive transport, also involved in active transport mechanism, the transport may not be affected by the P-protein, MRP2 protein, SGLT protein.


Assuntos
Medicamentos de Ervas Chinesas/farmacocinética , Isoflavonas/farmacocinética , Modelos Biológicos , Absorção , Transporte Biológico , Células CACO-2 , Cromatografia Líquida de Alta Pressão , Meios de Cultivo Condicionados/química , Estabilidade de Medicamentos , Medicamentos de Ervas Chinesas/análise , Humanos , Concentração de Íons de Hidrogênio , Isoflavonas/análise
18.
Bull Environ Contam Toxicol ; 93(4): 405-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25151280

RESUMO

Changes in protein levels and lipid compositions in algal cells indicate the severity of stress related to toxic concentrations of heavy metals. In this study, the effects of exposure to cadmium and copper on Chlorella vulgaris and its capacity to remove metals were evaluated. The data revealed ion removal activity by microalgae under all treatments and different levels of protein expression after 48 h of exposure. Furthermore, we analyzed lipids contents to characterize them.


Assuntos
Cádmio/metabolismo , Cádmio/toxicidade , Chlorella vulgaris/efeitos dos fármacos , Cobre/toxicidade , Absorção , Proteínas de Algas/metabolismo , Chlorella vulgaris/metabolismo , Cobre/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Análise de Componente Principal , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
19.
Chemosphere ; 112: 323-32, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25048923

RESUMO

Tannery sludge is available in plenty and is hazardous to environment as well as plant and animal life. It is very important to manage the tannery sludge in an environmentally sound manner. The aim of this study was to assess the physico-chemical, microbial and biochemical properties of soil treated with different levels of sludge. In this study, Tagetes minuta an essential oil bearing crop was grown in two different textured soils treated with different levels of tannery sludge. Application of tannery sludge (TS) increased the growth and oil yield of plant and also the activity of urease and soil microbial biomass nitrogen (SMBN) when applied in 50:50 combinations of soil:sludge. The crop performed well in coarse soil with a soil:sludge ratio of 50:50. High concentration of tannery sludge exhibited inhibitory effect on SMBN and urease activity. Acid/alkaline phosphatase, dehydrogenase and soil microbial biomass carbon (SMBC) increased as the sludge concentration increased in soil. This may be due to high organic matter present in tannery sludge. Roots accumulated more metal than the shoot. No detectable amount of metal was found in oil of T.minuta. To test the relation between 20 characters principal component analysis (PCA) was performed. PCA analysis indicates that cation exchange capacity (CEC), SMBC, dehydrogenase, acid and alkaline phosphatases were grouped in group 1. SMBN, urease and cis-ocimene content in oil were in group 2 whereas biomasss, chlorophyll a, limonene, Z and E-tagetone were in group 3. PC-I contributes 54% of total variance and PC-II contributes 38% of the total variance. The results concluded that T.minuta can mitigate metal toxicity by root absorption. Microbial activity and biomass of plant was higher in coarse soil with TS than fine soil with TS.


Assuntos
Metais Pesados/toxicidade , Óleos Voláteis/metabolismo , Esgotos/química , Poluentes do Solo/toxicidade , Solo/química , Tagetes/efeitos dos fármacos , Tagetes/crescimento & desenvolvimento , Absorção , Animais , Biodegradação Ambiental , Transporte Biológico , Biomassa , Clorofila/metabolismo , Clorofila A , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Metais Pesados/isolamento & purificação , Metais Pesados/metabolismo , Fosfatidilcolinas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Poluentes do Solo/isolamento & purificação , Poluentes do Solo/metabolismo , Tagetes/metabolismo
20.
Chemosphere ; 112: 487-95, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25048944

RESUMO

It is unknown whether metal absorption efficiencies in terrestrial soft-bodied species can be predicted with the same metal properties as for aquatic species. Here, we developed models for metal absorption efficiency from the dissolved phase for terrestrial worms and several aquatic species, based on 23 metal physicochemical properties. For the worms, the absorption efficiency was successfully related to 7 properties, and is best predicted with the ionic potential. Different properties (8 in total) were found to be statistically significant in regressions predicting metal absorption in aquatic species, with the covalent index being the best predictor. It is hypothesized that metal absorption by soft-bodied species in soil systems is influenced by the rate of metal supply to the membrane, while in aquatic systems accumulation is solely determined by metal affinity to membrane bound transport proteins. Our results imply that developing predictive terrestrial bioaccumulation and toxicity models for metals must consider metal interactions with soil solids. This may include desorption of a cation bound to soil solids through ion exchange, or metal release from soil surfaces involving breaking of metal-oxygen bonds.


Assuntos
Organismos Aquáticos/metabolismo , Metais/metabolismo , Oligoquetos/metabolismo , Poluentes do Solo/metabolismo , Absorção , Animais , Modelos Biológicos , Solo/química , Especificidade da Espécie
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