VALTER ARTHUR

VALTER ARTHUR

(Fonte: Lattes)

Resumo

Possui graduação em Biologia pela Universidade Metodista de Piracicaba (1977), mestrado em Energia Nuclear na Agricultura (Esalq) Universidade de São Paulo (1982) e doutorado em Agronomia (Entomologia) (Esalq) Universidade de São Paulo (1985). Atualmente é professor Associado no Centro de Energia Nuclear na Agricultura da Universidade de São Paulo. Tem experiência na área de Agronomia, com ênfase em Radioentomologia (tratamento quarentenário de pragas de importância agrícola) e Irradiação de alimentos (conservação e desinfecção de produtos agropecuários). (Texto extraído do Currículo Lattes em 27 dez. 2021)

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Plant extracts for the control of Sitophilus zeamais (Motschulsky, 1895) (Coleoptera: Curculionidae)
2023 - SOUZA, JULIANA N.A.; MARCOS, POTENZA R.; ARAUJO, MARCIO M. de; ROMANO, JAMILE I.S.; ARTHUR, VALTER
Brazil is one of the largest grain producers in the world, but its productive potential is threatened by the presence of stored product pests that compromise quality and quantity. The use of synthetic insecticides and selective pressure make many of these pests increasingly resistant to control. Concern for health and the environment requires the development of less toxic and persistent products for the management of these undesirable organisms. The insecticide activity of aqueous extracts of 15 vegetal species was evaluated to control grain beetles, Sitophilus zeamais Motschulsky in maize stored. The adult insects came from the laboratory at Biological Institute of Sao Paulo. They were fed with sterilized grains of maize and kept in a room at 25 +/- 2 degrees C and 70 +/-% of relative humidity. The plants for the aqueous extracts were crushed in distilled water and the vegetal mass was filtered next. The liquid resulting from the filtering process was stored in plastic containers and frozen for later use. Two tests were conducted: impregnation of filter paper and treatment of grains. Ten insects were evaluated in each batch. Only the aqueous extract of Dahlia pinnata Cavanilles was satisfactory in controlling S. zeamais showing an efficiency of 10.00% in the contact test and an efficiency of 56% in the treated corn kernels.
Histological evaluation of Rhipicephalus (Boophilus) microplus tick ovaries subjected to cobalt-60 ionizing radiation
2022 - PASQUALINI, ALEXANDRE A.; ARTHUR, VALTER; SCHIAVOLIN, MICHELEN B.; ABREU, MARINA R. de; CAMARGO-MATHIAS, MARIA I.
Females of Rhipicephalus (Boophilus) microplus ticks ingurgitated and in the prepost phase were submitted to doses of 0, 5, 10, 15, 20 and 25 Gy of Cobalt-60 with the aim of evaluating their effects on ovarian morphohistology with consequent establishment of the degree of damage caused to the reproductive organs of this species. For this purpose, 24 hours after exposure to Co-60 (142 Gy/h) the ectoparasites were dissected and had their ovaries removed and prepared for histology with haematoxylin and eosin staining. The results obtained showed that the 5 Gy dose radiation had a morphological aspect similar to the control standard adopted. The histological sections related to doses of 10 and 15 Gy did not cause many changes in the ovaries, except that changes were observed in the calf granules (size, distribution and staining pattern), as well as the extensive presence of cytoplasmic vacuoles in the ovocytes, especially in the region that makes contact with the ovocyte/pedicel, suggesting the occurrence of changes also in the physiology of the organ. In the ovaries exposed to doses of 20 and 25 Gy, severe alterations were observed in the organ as a whole, as well as in the germ cells (oocytes) which suffered alterations in size and shape, distribution of calf granules, involvement of the DNA present in the germinal vesicle (oocyte nuclei), besides the extensive cytoplasmic vacuolization, alterations which made the maturation of these cells impossible and consequently inhibited the production of new individuals.
Animal welfare provisions in cattery
2022 - ARTHUR, PAULA B.; LEANDRO, RODRIGO S.R.; HARDER, MARCIA N.C.; ARTHUR, VALTER
The present study had the objective of proposing adaptations for a permanent housing environment for neutered cats. Priorities and management practices were characterized by better animals health and quality of life. An animal observation survey was carried out on two different types of catteries: A, where the animals had an environment with greater freedom of movement, and cattery B, with animals with a reduced environment. The problems encountered in each were observed, such as sanitary, nutritional, and especially environmental management. Behavior was taken into account, according to the environment experienced by domestic cats castrated in confinement in the two different types of catteries. Based on the frequency and behavioral sequence of the groups analyzed, it was concluded that the environment of the cattery A promoted greater well-being of the animals.
Efeitos da radiação gama na conservação e desinfestação de frutos de lichia Litchi chinensis
2022 - HARDER, LARISSA N.C.; ARTHUR, VALTER
Efeitos da radiação gama na conservação e desinfestação de frutos de lichia Litchi chinensis
2021 - HARDER, LARISSA N.C.; ARTHUR, VALTER
The effects of microwave application on the physicochemical properties of bacaba (Oenocarpus bacaba Mart.) oil
2021 - FONSECA, HUGO M.; SANTOS, CAMILA O.; CRUZ, LUIS P.A.; ARTHUR, VALTER; FREITAS, BARBARA C.B.; SOUZA, ADRIANA R.M.; MARTINS, GLENDARA A.de S.
BACKGROUND Bacaba (Oenocarpus bacaba Mart.) has a high yield of oil, with the potential to produce biologically active natural products and can be considered a new "superfruit" with high value added. METHODS Acid value, peroxide value, refractive index, saponification value, p-anisidine value, relative density, iodine value, total oxidation value, specific extinction coefficients at 232 and 270 nm (K232 and K270), ΔK, and color were determined. RESULTS The most significant changes in the quality values, such as peroxide (26.25 mEq·kg-1), p-anisidine (11.41), acidity (14.66 mg KOH·g-1 oil), and total oxidation (63.92) were determined for 15 min of microwave heating. CONCLUSIONS The microwave heating promoted the acceleration of oxidative processes showing that, overall, much care should be taken when heating the bacaba oil by microwave to avoid oil degradation.
Natural coloring red beetroot under effects of gamma radiation
2021 - HARDER, MARCIA N.C.; FORMAGGIO, IAN H.; HARDER, LARISSA N.C.; BOVI, DEBORA C.M. de L.; ARTHUR, PAULA B.; ARTHUR, VALTER
As color is an important attribute related to the visual appeal and quality of food products, the reduction of pigment losses during food processing is a basic concern fr the industry. Based on this, the objective of this work was to evaluate the resistance of betalain from beet against the use of gamma radiation. Analyzes were carried out on pigments belonging to the betalain class on beets exposed to different doses of gamma radiation (Co60) using doses of 5, 10 and 15 kGy on beets, in addition to anon-irradiated sample for control. Color parameters were evaluated using the CIE L, a*, b * methodology, as well as the quantification of betalain in the samples. By of results the color parameters were affected in until 50% in relation the control. And the quantity betalain activity in the sample irradiated with doses of gamma radiation was more less 65% in relation the control. Therefore, it can be concluded that there is a potential resistance of the betalain pigment in the face of high doses of radiation, which returns interest to red beetroot dyes since most pigments are fragile to thermal treatments or with ionizing radiation.
Effects of gamma radiation in okra’s conservation
2021 - ARTHUR, PAULA B.; LEANDRO, RODRIGO S.R.; HARDER, LARISSA N.C.; HARDER, MARCIA N.C.; ARTHUR, VALTER
Okra is a very important vegetable in simple world cuisine. The aim of this work was to evaluate the effects of gamma radiation of Cobalt-60 in the conservation of okra (Abelmoschus esculentus). After 1 day of okras’s harvest, they were selected based in the size, presence of mechanical and phytophatologycal damages, and put in polystyrene trays and covered with thin polyethylene film. Then they were irradiated with doses of: 0 (control); 75; 100; 125; 150 and 200 Gy, at a dose rate of 0.259 kGy/h. The experiment was carried out in chamber regulated at 10o C of temperature and 80% of relative humidity. All analyses physical and chemical of the samples were carried out after 7 and 15 days of the storage. The results did not show any significative difference between the control and irradiated samples, except the viscosity that decreased with the increase of the dose of radiation. The dose of 75 Gy can be indicated to the conservation of okras because it was the one that showed best result in the coloration of okras.
Gamma radiation effects in precooked figs
2021 - HARDER, M.N.C.; HARDER, L.N.C.; LEANDRO, R.S.R.; ARTHUR, P.B.; ARTHUR, V.
Gamma radiation effects in jatoba flour
2021 - HARDER, M.N.C.; HARDER, L.N.C.; LEANDRO, R.S.R.; ARTHUR, P.B.; ARTHUR, V