RESUMEN
The size of ZnO nanorods (NRs) plays an important role in tuning the external quantum efficiency (EQE) and quality of light generated by white light emitting diodes (LEDs). In this work, we report on the enhancement of EQE and the quality of ZnO NR-based hetrojunction white LEDs fabricated on a p-GaN substrate using a low temperature solution method. Cathodoluminescence spectra demonstrate that ultraviolet (UV) emission decreases and visible deep band emission increases with an increase in the length of the ZnO NRs. The UV emission could be internally reabsorbed by the ZnO NR excitation, thus enhancing the emission intensity of the visible deep band. Photocurrent measurements validated the fact that the EQE depends on the size of ZnO NRs, increasing by 87% with an increase in the length of the ZnO NRs. Furthermore, the quality of white light was measured and clearly indicated an increase in the color rendering indices of the LEDs with an increase in the length of the ZnO NRs, confirming that the quality of light generated by LEDs can be tuned by varying the length of the ZnO NRs. These results suggest that the EQE and visible deep band emission from n-ZnONRs/p-GaN heterojunction LEDs can be effectively controlled by adjusting the length of the ZnO NRs, which can be useful for realizing tunable white LEDs.
RESUMEN
Withania somnifera is an ayurvedic Indian medicinal plant whose immunomodulatory activities have been widely used as a home remedy for several ailments. We recently observed immunostimulatory properties in the root extracts of chemotypes NMITLI-101, NMITLI-118, NMITLI-128 and pure withanolide, withaferin A. In the present study, we evaluated the potential immunoprophylactic efficacies of these extracts against an infective pathogen. Our results show that administration of aqueous ethanol extracts (10 mg/kg) and withaferin A (0·3 mg/kg), 7 days before and after challenge with human filarial parasite Brugia malayi, offers differential protection in Mastomys coucha with chemotype 101R offering best protection (53·57%) as compared to other chemotypes. Our findings also demonstrate that establishment of B. malayi larvae was adversely affected by pretreatment with withaferin A as evidenced by 63·6% reduction in adult worm establishment. Moreover, a large percentage of the established female worms (66·2%) also showed defective embryogenesis. While the filaria-specific immunological response induced by withaferin A and NMITLI-101 showed a mixed Th1/Th2 phenotype, 118R stimulated production of IFN-γ and 128R increased levels of IL-4. Taken together, our findings reveal potential immunoprophylactic properties of W. somnifera, and further studies are needed to ascertain the benefits of this plant against other pathogens as well.
Asunto(s)
Brugia Malayi/efectos de los fármacos , Filariasis Linfática/inmunología , Filariasis Linfática/prevención & control , Murinae/parasitología , Extractos Vegetales , Withania/química , Witanólidos , Animales , Brugia Malayi/crecimiento & desarrollo , Brugia Malayi/patogenicidad , Citocinas/biosíntesis , Filariasis Linfática/parasitología , Femenino , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , Larva/patogenicidad , Masculino , Extractos Vegetales/administración & dosificación , Extractos Vegetales/farmacología , Plantas Medicinales/química , Plantas Medicinales/clasificación , Enfermedades de los Roedores/inmunología , Enfermedades de los Roedores/parasitología , Enfermedades de los Roedores/prevención & control , Células TH1/inmunología , Células Th2/inmunología , Resultado del Tratamiento , Withania/clasificación , Witanólidos/administración & dosificación , Witanólidos/farmacologíaRESUMEN
A new, quick and economical decolorization assay based upon the generation of a radical cation made from promethazine hydrochloride (PMZH) is described for screening of antioxidant activity of plants/herbal extracts. PMZH radical cations, produced through a reaction between PMZH and potassium persulfate (K(2)S(2)O(8)) in phosphoric acid medium, have maximum absorption at 515 nm in their first-order derivative spectrum. Theconcentrations of chromagen and K(2)S(2)O(8) were optimized (final concentration of PMZH and K2S2O8 were 0.166 mM and 0.11 mM, respectively) for better stability and sensitivity of the radical cation produced. Agood linear correlation was found between the percentage inhibition and the increasing amounts of standard antioxidants, with correlation coefficients ranging from 0.989 to 0.999. The newly developed assay was employed to evaluate the antioxidant capacity of Citrullus colocynthes L. and Artemisia absinthium extracts. The proposed assay involved a more stable radical cation and required only 1 h for preparation of a working solution in comparison to the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolorizaion assay, which was reported to be less sensitive at low pH and almost 12-16 h were required for preparation of a working ABTS solution. Other assays employed to evaluate the antioxidant potential andradical-scavenging capacities of the extracts were the ferric-reducing antioxidant power, 2,2'-diphenyl-1-picrylhydrazyl radical scavenging, total phenolic contents assay, total flavonoid contents and metal-chelating activity assays, and the lipid peroxidation value in linoleic acid emulsion systems. The results indicate that boththe plants have potent free radical-scavenging activity and the ability to prevent lipid peroxidation and radical chain reactions.
Asunto(s)
Antioxidantes/química , Artemisia absinthium/química , Citrullus/química , Descubrimiento de Drogas/métodos , Depuradores de Radicales Libres/química , Extractos Vegetales/química , Prometazina/química , Antioxidantes/aislamiento & purificación , Flavonoides/análisis , Flavonoides/química , Flavonoides/aislamiento & purificación , Depuradores de Radicales Libres/aislamiento & purificación , Frutas/química , India , Indicadores y Reactivos/química , Quelantes del Hierro/química , Quelantes del Hierro/aislamiento & purificación , Medicina Tradicional , Pakistán , Fenoles/análisis , Fenoles/química , Fenoles/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Hojas de la Planta/química , Brotes de la Planta/química , Compuestos de Potasio/química , Solventes/química , Espectrofotometría , Sulfatos/químicaRESUMEN
In this study, temporal variability of nosZ genotypes was evaluated in two intertidal rocky biofilms and two intertidal sediment sites of the Douro River estuary, Portugal. The results were compared to rates of key N-cycle processes and environmental variables to examine possible links between denitrifier community dynamics and N biogeochemistry. Genetic heterogeneity of the nosZ gene was evaluated by terminal restriction fragment length polymorphism analysis (T-RFLP) and by sequencing cloned nosZ gene fragments. Phylogenetic analysis showed that the majority of the nosZ genes detected were most similar to nosZ genes from isolates affiliated with alpha-subclass of the class Proteobacteria. Results revealed low nosZ genotype richness, and hierarchical cluster analysis showed significant differences in the composition of denitrifier communities that inhabit different intertidal environments of the Douro River estuary. Monthly surveys of nosZ genotypes from sandy sediments showed that, while the same T-RFLP peaks were present in all samples, shifts in the relative peak areas of the different nosZ genotypes occurred. Canonical correspondence analysis, based on data from the monthly survey, revealed a strong relationship between the relative peak areas of some T-RFLP operational taxonomic units (OTUs) with denitrification rate and NO3- availability. Results suggest that denitrifiers with specific nosZ genotypes (OTUs) have competitive advantage over others when NO3- fluctuates in the system; these fluctuations reflect, in turn, variability in denitrification rates.
Asunto(s)
Fenómenos Fisiológicos Bacterianos , Biopelículas/crecimiento & desarrollo , Sedimentos Geológicos/microbiología , Nitrógeno/metabolismo , Oxidorreductasas/genética , Ríos/microbiología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Análisis por Conglomerados , ADN Bacteriano/genética , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Portugal , Análisis de Secuencia de ADN , Microbiología del SueloRESUMEN
AIMS: To characterize the phylogenetic composition of ammonia-oxidizing bacteria (AOB) of the beta-subclass of the class Proteobacteria in intertidal sediment and rocky biofilms of the Douro estuary, and evaluate relationships with environmental variables and N-biogeochemistry. METHODS AND RESULTS: Cluster analysis of denaturing gradient gel electrophoresis profiles showed differences in beta-Proteobacteria AOB assemblage composition between rocky biofilms and sediments. All sequences obtained from intertidal rocky biofilm sites exhibited phylogenetic affinity to Nitrosomonas sp. lineages, whereas a majority of the sequences from the sediment sites were most similar to marine Nitrosospira cluster 1. Hierarchical cluster analysis based on environmental variables identified two main groups of samples. The first contained samples from rocky biofilm sites characterized by high concentrations of NO2- and NH4+, and high organic matter and chlorophyll a content. The second group contained all of the sediment samples; these sites were characterized by lower values for the variables above. In addition, rocky biofilm sites exhibited higher nitrification rates. CONCLUSIONS: Intersite differences in environmental and/or physical conditions led to the selection of different populations of beta-Proteobacteria AOB, supporting different magnitudes of N-cycling regimes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study represents an important step in establishing the influence of environmental factors on the distribution of beta-Proteobacteria AOB with possible consequences for N-biogeochemistry.
Asunto(s)
Amoníaco/metabolismo , Betaproteobacteria/clasificación , Biopelículas , Sedimentos Geológicos/microbiología , Ríos/microbiología , Técnicas de Tipificación Bacteriana/métodos , Betaproteobacteria/genética , Betaproteobacteria/aislamiento & purificación , Betaproteobacteria/metabolismo , Análisis por Conglomerados , ADN Bacteriano/análisis , Electroforesis en Gel de Poliacrilamida/métodos , Datos de Secuencia Molecular , Oxidación-Reducción , Filogenia , Reacción en Cadena de la Polimerasa/métodos , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Estaciones del AñoRESUMEN
The isolate NJ-101 obtained from agricultural soil was characterized and presumptively identified as Pseudomonas sp. The isolate exhibited efficient degradation of the insecticide carbofuran with a rate constant of 0.035 day(-1), following first-order rate kinetics. The ability of performing multifarious biological activities in tandem suggested the uniqueness of isolate NJ-101. The ability to produce hydrogen cyanide and siderophore stipulated its role in biological control. Furthermore, the growth inhibition of Fusarium sp. validated the antagonistic activity of NJ-101 against the common phytopathogens. Concurrent production of indole acetic acid, and solubilization of inorganic phosphate revealed its plant growth promoting potential. Thus, the innate capability of this novel isolate for parallel biodegradation, biocontrol and plant growth promotion has significance in management of the agro-environmental and phytopathological problems.
Asunto(s)
Carbofurano/metabolismo , Control Biológico de Vectores , Pseudomonas/metabolismo , Biodegradación Ambiental , Enfermedades de las Plantas/microbiología , Pseudomonas/clasificación , Pseudomonas/aislamiento & purificación , Pseudomonas/fisiología , Microbiología del SueloRESUMEN
Phorate [O,O-diethyl-S-(ethylthio)methyl phosphoradiothioate] degrading bacteria were isolated from agricultural soil and characterized based on their morphological and biochemical characteristics. The selected isolates PS-1, PS-2 and PS-3 were presumptively identified as Rhizobium, Pseudomonas and Proteous species, respectively. The HPLC analysis of phorate in bioaugmented soil revealed its complete disappearance within 40 days. The degradation isotherms of the isolates PS-1, PS-2 and PS-3 suggested time-dependent disappearance of phorate following the first order rate kinetics at the corresponding rate constants of 0.04, 0.05 and 0.04 days-1. Besides, the isolates concurrently exhibited substantial phosphate solubilization, indole acetic acid, and siderophore production. The isolate PS-3 also showed anti-fungal activity against a phytopathogen Fusarium oxysporum. As a result of the multifarious biological properties, the isolates have been suggested to be important bioresource for efficient bioinoculant development.
Asunto(s)
Bacterias Gramnegativas/clasificación , Bacterias Gramnegativas/aislamiento & purificación , Insecticidas/metabolismo , Forato/metabolismo , Microbiología del Suelo , Agricultura , Antibiosis , Biodegradación Ambiental , Fusarium/crecimiento & desarrollo , Bacterias Gramnegativas/crecimiento & desarrollo , Ácidos Indolacéticos/metabolismo , Fosfatos/metabolismo , Proteus/clasificación , Proteus/crecimiento & desarrollo , Proteus/aislamiento & purificación , Pseudomonas/clasificación , Pseudomonas/aislamiento & purificación , Rhizobium/clasificación , Rhizobium/aislamiento & purificación , Sideróforos/metabolismo , Contaminantes del Suelo/metabolismoRESUMEN
The spatial distribution and diversity of ammonia-oxidizing bacteria of the beta subdivision of the class Proteobacteria (hereinafter referred to as ammonia oxidizers) in the Arctic Ocean were determined. The presence of ammonia oxidizers was detected by PCR amplification of 16S rRNA genes using a primer set specific for this group of organisms (nitA and nitB, which amplifies a 1.1-kb fragment between positions 137 and 1234, corresponding to Escherichia coli 16S rDNA numbering). We analyzed 246 samples collected from the upper water column (5 to 235 m) during March and April 1995, September and October 1996, and September 1997. Ammonia oxidizers were detected in 25% of the samples from 5 m, 80% of the samples from 55 m, 88% of the samples from 133 m, and 50% of the samples from 235 m. Analysis of nitA-nitB PCR product by nested PCR-denaturing gradient gel electrophoresis (DGGE) showed that all positive samples contained the same major band (band A), indicating the presence of a dominant, ubiquitous ammonia oxidizer in the Arctic Ocean basin. Twenty-two percent of the samples contained additional major bands. These samples were restricted to the Chukchi Sea shelf break, the Chukchi cap, and the Canada basin; areas likely influenced by Pacific inflow. The nucleotide sequence of the 1.1-kb nitA-nitB PCR product from a sample that contained only band A grouped with sequences designated group 1 marine Nitrosospira-like sequences. PCR-DGGE analysis of 122 clones from four libraries revealed that 67 to 71% of the inserts contained sequences with the same mobility as band A. Nucleotide sequences (1.1 kb) of another distinct group of clones, found only in 1995 samples (25%), fell into the group 5 marine Nitrosomonas-like sequences. Our results suggest that the Arctic Ocean beta-proteobacterial ammonia oxidizers have low diversity and are dominated by marine Nitrosospira-like organisms. Diversity appears to be higher in Western Arctic Ocean regions influenced by inflow from the Pacific Ocean through the Bering and Chukchi seas.
Asunto(s)
Amoníaco/metabolismo , ADN Bacteriano/genética , ADN Ribosómico/genética , Variación Genética , Filogenia , Proteobacteria/clasificación , Proteobacteria/genética , Agua de Mar/microbiología , Regiones Árticas , Secuencia de Bases , Cartilla de ADN , Océanos y Mares , Oxidación-Reducción , Reacción en Cadena de la Polimerasa , Proteobacteria/aislamiento & purificación , ARN Ribosómico 16S/genética , Estaciones del AñoRESUMEN
A healthy 22-year-old man received an initial injection of 12 mL of lignocaine/bupivacaine solutions (2 mL test, then 10 mL) into an epidural catheter. This produced a satisfactory regional blockade that seemed to be epidural but, when a supplementary 6 mL injection was given 1 h later, the patient developed impaired motor function as far as the upper cranial nerves, with loss of pinprick sensation to the shoulder. The emergence of fluid dribbling freely from the catheter prompted measurement of the pressure, which was 36 mmHg. The fluid was proved not to be cerebrospinal fluid (CSF) by the absence of glucose (on dextrostix), by the appearance of turbidity with added thiopentone, and later by microscopy. Slow aspiration of 7 mL of the presumed injectate reduced the pressure in the catheter to 8 mmHg, which promptly reversed the additional excessive blockade, allowing surgery to proceed uneventfully. The retrieval of injectate argues strongly that the catheter tip had found its way subdurally, and the promptness of the reversal with aspiration argues for a mechanical rather than a pharmacological cause for the extensive neurological dysfunction after the second injection. Pressure measurement and aspiration may be helpful in other similar cases.
Asunto(s)
Analgesia Epidural/efectos adversos , Anestésicos Locales/efectos adversos , Espacio Subdural , Adulto , Anestésicos Locales/administración & dosificación , Glucemia/metabolismo , Humanos , Complicaciones Intraoperatorias , Masculino , Uretra/lesiones , Uretra/cirugíaRESUMEN
Regular biting collections were conducted in 1993-1994 to investigate seasonal fluctuations in the abundance of anophelines in Afghan refugee villages in north-western Pakistan. Enzyme-linked immunosorbent assay were used to test heads-plus-thoraces for the presence of malaria sporozoites. Anophelines giving positive results for Plasmodium vivax were captured in every month except January. Nine species were positive. Biting rates showed a marked increase in May, after the spring rains, and thus spring transmission of vivax malaria seems certain. However, transmission of vivax malaria reached its peak only after the monsoon in July. To determine the optimal time to control vivax malaria by indoor spraying with residual insecticide, spray campaigns were conducted in either spring or summer in 14 refugee villages. Villages sprayed in July 1994 showed a mean reduction in annual incidence of 62% (95% confidence interval [CI] +/-6%) relative to the previous year, whereas villages sprayed in April 1994 showed only a 15% reduction (95% CI +/- 32%). Parasite prevalence surveys conducted in April and October 1994 confirmed the greater efficacy of spray campaigns waged in July. The insecticide malathion proved as effective as the pyrethroid lambdacyhalothrin, even though several species of anopheline were resistant to malathion.
Asunto(s)
Malaria Vivax/transmisión , Control de Mosquitos , Afganistán/etnología , Animales , Anopheles , Humanos , Incidencia , Insecticidas , Malaria Falciparum/epidemiología , Malaria Vivax/epidemiología , Malaria Vivax/prevención & control , Malatión , Nitrilos , Pakistán/epidemiología , Piretrinas , Refugiados , Estaciones del Año , Factores de TiempoRESUMEN
Nutritional beliefs and practices in 100 pregnant and 100 lactating women were assessed in an urban and rural area of Lahore. A structured questionnaire was used for the purpose. Seventy seven percent women and 54% of their husbands were illiterate, 50.5% belonged to a family with a per capita income of more than Rs.300.00 per month, 52.5% had 7 or more family members and 56% were living in nuclear families. The age of mothers, type of family, literacy, family income, parity and gravidity had not significantly influenced the nutritional beliefs and practices, only urban and rural differences were statistically significant. Eight-four percent of mothers had knowledge that diet should be changed by increasing, adding or avoiding some special food items in the diet during pregnancy and lactation, but only 65.5% practiced them. The reasons for this deficient knowledge and practice of dietary intake are lack of nutritional knowledge and poor economy. However, this can be overcome by improving nutritional knowledge and dietary practices of population in general and vulnerable groups in particular through media and MCH services on the use of locally available low cost nutritious foods and to avoid undue food restrictions. Improvement of applied nutritional knowledge of medical professionals is also necessary.