<p>We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade / , Rovral&trade / , Terminator&trade / and Teldor&trade / at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade / significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.</p>

No description available.

The importance of monitoring, and where possible reducing, the level of radiation dose from diagnostic X-ray examinations has been recognised for many years and is becoming of increasing concern. Dose reduction is of particular concern in paediatric radiology, and there are specific problems associated with the monitoring and comparison of radiation doses to children. Any optimisation study relies on a framework of good dosimetry. Two techniques have been developed to improve the collection of patient dose data: the automation of survey techniques to increase the quantity of data collected; and a method of correcting for patient size which reduces one source of variability in the data. An optimisation strategy has been developed, consisting of theoretical simulations, experimental verification and clinical implementation. Monte Carlo techniques were used for the theoretical study, which investigated the effect of beam filtration on radiation dose and image quality for a wide range of parameters, specifically for a neonatal size phantom. Simulations included both radiography of bone in soft tissue and fluoroscopy of iodine and barium based contrast media. The results were assessed in terms of the beam spectra and the absorption and transmission characteristics of the phantom and image receptor. Experimental measurements of dose and contrast were made for a simple slab phantom corresponding to that simulated, and results showed good agreement with those predicted. A further set of experimental measurements were carried out using anthropomorphic phantoms in a clinical setting, which demonstrated how the theoretical predictions translated to clinical practice. A clinical trial of the use of a 0.1mm copper filter for fluoroscopic examinations of infants was performed, and the filter shown to give substantial dose reduction with no significant loss in image quality. Some general recommendations on dose quantities and the application of optimisation strategies to paediatric radiology have been made.

<p>We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade / , Rovral&trade / , Terminator&trade / and Teldor&trade / at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade / significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.</p>

Neste trabalho são apresentados os resultados obtidos com diodos resistentes a danos de radiação dos tipos fusão zonal padrão (FZ), fusão zonaI com difusão de oxigênio (DOFZ) e Czochralski magnético (MCz) em dosimetria de processamento por radiação gama. Estes dispositivos de junção p+-n-n+ foram manufaturados por Okmetic Oyj. (Vantaa, Finland) e processados no Centro de Microeletrônica da Universidade de Tecnologia de Helsinki no âmbito da colaboração RD50 do CERN. As sondas dosimétricas, baseadas nos dispositivos FZ, DOFZ and MCz, foram projetadas para operar sem tensão de polarização no modo de corrente direta como dosímetros on-line de radiação. As irradiações foram realizadas no Centro de Tecnologia das Radiações (CTR) no IPEN-CNEN/SP usando a fonte de 60Co (Gammacell 220 Nordion) com a taxa de dose de aproximadamente 2,4 kGy/h. A resposta em corrente de cada diodo foi medida em função do tempo de exposição em intervalos de dose desde 5 kGy até 50 kGy atingindo a dose total absorvida 275 kGy. Os resultados obtidos demonstraram um significante decréscimo da fotocorrente gerada em todos os dispositivos para doses totais absorvidas superiores a aproximadamente 25 kGy. Para reduzir este efeito, as amostras foram pré-irradiadas com raios gama do 60Co a uma dose de 700 kGy, para saturar a produção de armadilhas no volume sensível do diodo. Depois da pré-irradiação, apesar de serem menos sensíveis, todos os dispositivos apresentaram sinais de corrente estáveis mesmo para a dose total absorvida de 275 kGy. A fim de monitorar possíveis efeitos de danos de radiação VII produzidos nos diodos, as correntes de fuga e capacitância destes dispositivos foram medidas em função da dose total absorvida. As curvas de calibração dos dosímetros mostraram respostas quadráticas com coeficientes de correlação maiores do que 0,9999 para doses totais absorvidas de até 275 kGy. A comparação entre as respostas dosimétricas dos diodos estudados evidenciou que o melhor resultado foi obtido com o MCz que exibiu maiores sensibilidade e estabilidade do que os dispositivos FZ e DOFZ. No entanto, é importante notar que todos os diodos pré-irradiados podem ser utilizados como dosímetros em aplicações de processamento por radiação gama. / In this work we report on results obtained with rad-hard Standard Float Zone (FZ), Diffusion Oxygenated Float Zone (DOFZ) and Magnetic Czochralski (MCz) silicon diodes in gamma radiation processing dosimetry. These p+-n-n+ junction devices were manufactured by Okmetic Oyj. (Vantaa, Finland) and processed by the Microelectronics Center of Helsinki University of Technology in the framework of the CERN RD50 Collaboration. The dosimetric probes, based on FZ, DOFZ and MCz devices, were designed to operate without bias voltage in the direct current mode as on-line radiation dosimeter. The irradiations were performed in the Radiation Technology Center (CTR) at IPEN-CNEN/SP using a 60Co source (Gammacell 220 Nordion) with a dose rate around of 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. The results obtained showed a significant decrease in the photocurrent generated in all devices for total absorbed doses higher than approximately 25 kGy. To reduce this effect, the samples were pre-irradiated with 60Co gamma rays at 700 kGy in order to saturate the trap production in the diodes sensitive volume. After pre-irradiation, despite of being less sensitive, all devices exhibited more stable photocurrent signals, even for total absorbed doses of 275 kGy. To monitor possible gamma radiation damage effects produced on the diodes, their dynamic leakage current and capacitance were measured as a function of the absorbed dose. IX The calibration curves of the dosimeters showed quadratic responses with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison among the dosimetric response of the diodes studied evidenced that the best result was achieved with the MCz which exhibited higher sensitivity and stability than the FZ and DOFZ devices. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications.

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