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1.
As insects increase in radiotolerance as they develop and usually several developmental stages of the pest may be present in the fresh shipped commodity, it is important to know the radiation susceptibility of the stages of the target insect before the establishment of ionizing radiation quarantine treatments. This study was performed to determine the radiotolerance of eggs of the oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), to gamma radiation. This species is considered as one of the most serious worldwide pests for temperate fruits, especially peaches. Eggs (12 h old) were exposed to 0 (control), 25, 35, 50, 75, 100, 125 and 150 Gy of gamma radiation. Surviving larvae were allowed to feed on an artificial diet. Three days after irradiation, it was verified that larvae’s cephalic capsules were significantly affected by gamma radiation, and the estimated mean LD90 and LD99 were 66.3 Gy and 125.8 Gy, respectively. Oriental fruit moth eggs revealed to be quite radiosensitive and very low doses as 50 Gy were sufficient to disrupt G. molesta embryogenesis. At 25 Gy, only male adults originated from the surviving larvae and, after mating with untreated fertile females, shown to be sterile.  相似文献   

2.
Hawaii is a pioneer in the use of phytosanitary irradiation. The commercial X-ray irradiation facility, Hawaii Pride LLC, has been shipping papaya and other tropical fruits and vegetables to the United States mainland using irradiation for 11 years. Irradiation is an approved treatment to control quarantine pests in 17 fruits and 7 vegetables for export from Hawaii to the US mainland. Hawaiian purple sweet potato is the highest volume product with annual exports of more than 12 million lbs (5500 t). The advent of generic radiation treatments for tephritid fruit flies (150 Gy) and other insects (400 Gy) will accelerate commodity export approvals and facilitate worldwide adoption. Lowering doses for specific pests and commodities can lower treatment costs and increase capacity owing to shorter treatment times, and will minimize any quality problems. Current impediments to wider adoption include the 1 kGy limit for fresh horticultural products, the labeling requirement, and non-acceptance of phytosanitary irradiation in Japan, the European Union, and elsewhere. Irradiation has potential as a treatment for unregulated imports to prevent new pest incursions.  相似文献   

3.
The yield increase of secondary metabolite production was examined in plant cell cultures with the use of relatively low to high doses gamma irradiation. Suspension culture of Lithospermum erythrorhizon cells was irradiated to 2, 16, and 32 Gy. The gamma irradiation significantly stimulated the shikonin biosynthesis of the cells and increased the total shikonin yields (intracellular+extracellular shikonin yields) by 400% at 16 Gy and by only 240% and 180% at 2 and 32 Gy, respectively. One of the key enzymes for the shikonin biosynthesis of cells, p-hydroxylbenzoic acid (PHB) geranyltransferase, was found to be stimulated by the gamma-radiation treatments. The activity of PHB geranyltransferase was increased at 2 and 16 Gy with a negligible change at 32 Gy. In contrast, the activity of PHB glucosyltransferase was slightly changed at all doses of gamma radiation compared with the control cells. Therefore, the increase in PHB geranyltransferase activity leads to the accumulation of secondary metabolites such as a shikonin, which may contribute to plant defense against the stresses induced by gamma irradiation.  相似文献   

4.
The dosimetry characteristics of various solutions of tetrazolium violet, TV, (2,5-diphenyl-3-(1-naphthyl)-2H-tetrazolium chloride) to gamma irradiation are reported. The optical absorption spectra of these solutions show peaks between 400 and 600 nm with a shoulder at around 550 nm. The dose response of the optical absorbance values of aqueous and aqueous-alcoholic solutions containing different concentrations of TV was measured in the 250 Gy up to 75 kGy dose range. The formation of formazan product was observed due to radiolytic reduction in both solutions. Its formation was found more pronounced in N2-saturated as well as in alkaline solutions. The results indicate that the 1 mM TV solution can be used for food irradiation and medical sterilization dosimetry at gamma irradiation facilities.  相似文献   

5.
Eggs of the grape vine moth, Lobesia botrana (Denis and Schiffermuller), ranging in age from 1–24 to 73–96 h, were exposed, at 24 h intervals, to gamma radiation ranging from 25–600 Gy. The effects of gamma radiation on egg hatch, pupation, adult emergence, sex ratio and rate of development were examined. Results showed that the radiosensitivity of the grape vine moth eggs decreased with increasing age and increased with increasing radiation dose. Egg hatch in 1–24 h old eggs was significantly affected at 25 Gy and completely prevented at 100 Gy. At the age of 25–48 h, radiation sensitivity was only a little lower; egg hatch at 100 Gy was <1% and at 125 Gy no egg hatch was observed. Egg sensitivity to gamma irradiation decreased significantly in the 49–72 h age group; egg hatch was 66% at 100 Gy, and 500 Gy did not completely stop egg hatch (<1%). Eggs irradiated a few hours before egg hatch (73–96 h old) were the most resistant; 150 Gy had no significant effect on egg hatch and at 600 Gy over 33% of the eggs hatched. When pupation or adult emergence was used as a criterion for measuring effectiveness, however, the effects of gamma radiation were very severe. In the most resistant age group (73–96 h old), 150 Gy completely prevented pupation and adult emergence and all larvae resulting from eggs irradiated <49 h old died before pupation. In addition, the rate of development of immature stages resulting from irradiated eggs was negatively affected and sex ratio was skewed in favor of males.  相似文献   

6.
Precise water activity measurements at T = 308.15 K were carried out on several binary (water + polymer) and ternary {water + polymer (1) + polymer (2)} systems using the vapour pressure osmometry (VPO) technique. Polymers were polyethylene glycol 400 (PEG400), polyethylene glycol 6000 (PEG6000), polypropylene glycol 400 (PPG400), polyvinylpyrrolidone (PVP) and dextran (DEX). The water activity results obtained were used to calculate the vapour pressure of solutions as a function of concentration and the segment-based local composition models, NRTL and Wilson, were used to correlate the experimental water activity values. It was found that, for the polymer concentration range studied here, the values of the water activity obtained for the binary (water + polymer) solutions decrease in the order DEX > PVP > PEG6000 > PPG400 > PEG400. Furthermore, water activities of solutions of each polymer in the aqueous solutions of (5, 10, 15 and 20)% (w/w) other polymers investigated were also measured at T = 308.15 K. The ability of polymer (1) in decreasing the water activity of binary {water + polymer (2)} solutions was discussed on the basis of the (polymer + water) and {polymer (1) + polymer (2)} interactions.  相似文献   

7.
Batch-mode pyrolysis of 200.0 g samples of polymers was studied at low temperature. The cracking reaction was carried out in a stainless-steel autoclave with reaction temperatures of 360, 380, 400 and 420 °C, initial pressure of 6.325 kPa (absolute pressure) and reaction times of 0–240 min. Based on the experimental results, a four-lump kinetic model has been developed to describe the production distribution of the light fractions, middle distillates and heavy fraction. This model reasonably fitted the results in each reaction of operation conditions. It was also found that the pyrolysis kinetics of separated plastic, mixed plastic and mixed plastic containing additives can be described by the same kinetic model. The plastic additives have not had a great influence on the product distribution and kinetics of the mixed plastic pyrolysis. Finally, the optimum conditions of low-temperature conversion of plastic mixtures to value-added products were established. The formation of heavy fractions from HDPE was as high as 70 wt% at 380 °C at a reaction time of 250 min. During the thermal degradation of plastic mixtures, the heavy fractions yielded up 50 wt% for 30 min reaction time at 400 °C. The total activation energies for the conversion of HDPE and the plastic mixtures were estimated to be 217.66 kJ mol−1 and 178.49 kJ mol−1, respectively.  相似文献   

8.
Polyimide (PI) is a commonly used polymer in microelectronics. Recently, numerous PI-based flexible neural interfaces have been developed for reducing mechanical mismatch between rigid implant and soft neural tissue. Most approaches employ non-photosensitive PI, which has been proven earlier to be biocompatible. However, photosensitive polyimide (PSPI) would simplify device fabrication remarkably, but its biocompatibility has been only sparsely reported. In this study, cytotoxicity of spin-coated PSPI (HD Microsystems PI-2771) and conventional PI (HD Microsystems PI-2525) films were evaluated in vitro using BHK-21 fibroblasts according to the ISO-10993-5 standard. PSPIs were tested as cured at a temperature of 200 °C (PI-2771-200) and 350 °C (PI-2771-350). The PI film surfaces were characterized in terms of their roughness, energy and zeta potential which are hypothesized to affect cell–material interactions. The values of the total surface free energy (SFE), and its polar and dispersive component, were significantly (p < 0.001) greater for the PI-2525 film (SFE: 47.3 mJ/m2) than for the PI-2771-200 (25.6 mJ/m2) or PI-2771-350 films (26.2 mJ/m2). The curing temperature of the PI-2771 had a significant effect on the zeta potential values (p < 0.001), but not on surface energy (p = 0.091) or roughness (p = 0.717). The results from the MTS proliferation assays and live/dead staining revealed that PSPI is almost as non-cytotoxic as conventional PI and polyethylene (negative control). The morphology and spreading of BHK-21 cells were similar on all the PI materials tested. In conclusion, PSPI seems to be a promising biocompatible material, while further studies in vitro and in vivo are needed to clarify the long-term effects.  相似文献   

9.
In this work, the performance of integrated photocatalytic and biological treatment was studied for the degradation of 4-chlorophenol (MCP) present in wastewaters. Photocatalysis was used as a pre-treatment to biological degradation. Pollutant removal efficiency was quantified using MCP removal and total organic carbon (TOC) removal. Both photocatalytic as well as biological treatments were carried out in batch reactors, using TiO2 as the photocatalyst. The inoculum for biological experiments was obtained from paper mill effluent treatment plant and was developed through a process of selection and acclimatization. Effect of TiO2 concentration on the photocatalytic degradation of MCP was studied along with the effect of the duration of photochemical oxidation and glucose concentrations (0 g/L, 1 g/L and 2 g/L) on the biodegradation of MCP. Integrated biological and photochemical degradation was found to be more effective in treating MCP, especially at higher concentrations (400 mg/L). An initial MCP concentration of 400 mg/L required 96 h for complete mineralization when treated with the process combination, whereas the treatment went on up to 264 h when biodegradation alone was employed.  相似文献   

10.
In the last few years, coal mine methane (CMM) has gained significance as a potential non-conventional gas fuel. The progressive depletion of common fossil fuels reserves and, on the other hand, the positive estimates of CMM resources as a by-product of mining promote this fuel gas as a promising alternative fuel. The increasing importance of its exploitation makes it necessary to check the capability of the present-day models and equations of state for natural gas to predict the thermophysical properties of gases with a considerably different composition, like CMM. In this work, accurate density measurements of a synthetic CMM mixture are reported in the temperature range from (250 to 400) K and pressures up to 15 MPa, as part of the research project EMRP ENG01 of the European Metrology Research Program for the characterization of non-conventional energy gases. Experimental data were compared with the densities calculated with the GERG-2008 equation of state. Relative deviations between experimental and estimated densities were within a 0.2% band at temperatures above 275 K, while data at 250 K as well as at 275 K and pressures above 10 MPa showed higher deviations.  相似文献   

11.
Nanoparticles of α-Bi2Mo3O12 were prepared by co-precipitation method at calcination temperatures of 250, 300, 400 and 480 °C. The characterization of α-Bi2Mo3O12 synthesized at different temperatures was carried out by X-ray diffraction (XRD), thermal analysis (TGA/DTA), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS). Adsorption parameters and photocatalytical activity under visible light irradiation of α-Bi2Mo3O12 were evaluated using the rhodamine B (rhB) dye as model. The adsorption constant (K) and maximum amount of dye adsorbed (qmax) on the surface of the samples synthesized were evaluated following the Langmuir isotherm. The sample calcinated at 250 °C showed the maximum adsorption percentage of dye, which ranged between 20 and 46% for initial concentrations of rhB from 5 to 15 mg L?1, with a K = 6.96 × 105 L mol?1 and qmax = 2.73 mg g?1. All samples were able to induce the oxidative photodegradation of rhB, however, the bleaching of dye solution was reached more quickly for the sample calcinated at 250 °C.  相似文献   

12.
《Comptes Rendus Chimie》2014,17(7-8):785-789
In the context of fuel upgrading by selective ring opening of naphthenes, we have investigated the catalytic conversion of cyclopentane in large hydrogen excess over iridium and platinum single-crystal surfaces. Both (111) and (112) orientations have been considered. The catalytic tests have been performed at 1 kPa and 25–600 °C using a recently developed surface reactor equipped with laser heating and online gas chromatography. Only cyclopentene and C1–C4 cracking products are formed on iridium, while platinum additionally catalyzes the formation of pentane around 200 °C, which dehydrogenates to pentene at 250 °C. Noticeably, on both metals, the surface steps prevent hydrocarbon cracking (up to 400 °C) at the benefit of dehydrogenation. In all cases, a carbon overlayer is formed on the surfaces in the course of the reaction.  相似文献   

13.
Spectrometer settings for ESR readout of alanine dosimeters for radiotherapy have been investigated. Several ESR parameters were studied and determined. The main reason for this work is to choose the suitable parameters to increase signal-to-noise ratio and to reduce the uncertainty on ESR readout, which is one of the main components of uncertainty of alanine/ESR dosimetry system for radiotherapy. The new spectrometer settings have been applied for ESR readout of alanine dosimeters irradiated from 1 to 10 Gy. A higher signal-to-noise ratio has been achieved compared to our old spectrometer settings. The extended uncertainty (k=2) has been evaluated in the dose range 2–10 Gy (maximum uncertainty of 4.9% for 2 Gy, while minimum uncertainty of 1.4% for 10 Gy), which implies that the alanine/ESR dosimetry system can be applied to radiotherapy dose level that needs a global accuracy of 5%.  相似文献   

14.
Brazil is one of the largest mango producers and the third largest mango exporter worldwide. Irradiation treatment and its commercial feasibility have been studied in our country to make it possible to develop new markets and, consequently, to compete with the major exporters of mangoes, Mexico and India. This work was designed to compare irradiation treatment with the hot water dip treatment in mangoes cv. Tommy Atkins for export and to verify that the main attributes for acceptance, color and texture, as well as carbohydrate and organic acid contents, were maintained. In this study, the fruit was divided into groups: control, hot water dip-treated (46 °C for 90 min), and irradiation-treated at doses of 0.4 kGy and 1.0 kGy. The fruit was stored at low temperature (11 °C±2) for 14 days and then at room temperature (23 °C±2) until the end of the study. The results indicated that the fruit given a dose of 1.0 kGy remained in a less advanced stage of ripening (stage 3) throughout the storage period, but experienced a greater loss of texture in the beginning of the experiment. It was noted that only the control group had higher levels of citric acid and succinic acid on the last day of the experiment. There were no significant differences in the total sugar content between any treatment groups. Gamma radiation can be used as a quarantine treatment and does not interfere negatively with the quality attributes of mangoes.  相似文献   

15.
Porous silica–zirconia membranes were fabricated by the sol–gel techniques to study their stability against water and the pervaporation performance of aqueous solutions of organic solvents. Zirconia (10–70 mol%) was added to silica to obtain silica–zirconia composite membranes by firing at 400–500 °C for pervaporation tests with organic solvent/water mixtures, such as iso-propyl alcohol (IPA)/water and tetrahydrofuran (THF)/water mixtures at their normal boiling points.The membrane coatings have been done effectively by the hot-coating methods proposed previously. Boiling water treatments introduced in the coating processes have made the membranes quite stable even in the high water concentration region of aqueous organic solutions at their normal boiling points. Zirconia contents larger than about 40 mol% have made the silica–zirconia membranes quite stable. The membranes of zirconia contents less than about 30 mol% were found not stable in a dilute aqueous solution of IPA. The membranes fabricated by the conventional dip-coating methods with slow drying were not stable against water because of the probable segregation of silica and/or silica-rich phases during drying.The membranes fired at lower temperature (400 °C) gave a higher water flux of around 500 mol m−2 h−1 (9 kg m−2 h−1) with a separation factor larger than 1500 at 10 wt.% of water in the boiling feed of IPA/water mixture, for example.  相似文献   

16.
We present a very simple electrospray unit, a capillary spray cell, for easy analysis of small (10–50 μL) sample aliquots. The sample, e.g., an unfiltered extract, is injected to a small sample cell, made of alumina and containing a short fused silica capillary mounted in its side. By the application of a 5 kV potential between the sample cell and the entrance orifice of a mass spectrometer with an atmospheric pressure interface, the sample is dragged out of the cell at a rate of a few μL/min and an electrospray is generated at the tip of the silica capillary. The capillary spray cell benefits from a high internal diameter (up to 250 μm) and very easy and inexpensive replacement of the capillary, which makes the sprayer well suited for analysis of unfiltered extracts. We demonstrate the direct analysis of extracts from plants and insects. In quantitative measurements using internal standards, a relatively high sensitivity (low ng/mL) is obtained together with good linearity (R2 = 0.998) in the range of 10–1000 ng/mL. The capillary spray cell is also suited for use with field portable mass spectrometers, since no syringe pump or nebulizer gas is needed. Furthermore, the capillary spray cell is easily manufactured by most mechanical workshops.  相似文献   

17.
There are a lot of natural resources that potentially used as herbal medicines in Indonesia. Some of the herbs, like Dewa leaves (Gynura pseudochina (L) D.C) and temu ireng rhizome (Curcuma aeruginosa Roxb.), were ussually used to increase number of thrombocytes in dengue patient. This current study was to determine the potential of dewa leaves (Gynura pseudochina (L) D.C) and temu ireng rhizome (Curcuma aeruginosa Roxb.) against the number of trombocytes, erythrocytes, and hematocrits level on male white rats (Rattus novergicus) by using Heparin Induction. Dosages of the extracts were 250 mg/kg BW and 500 mg/kg BW used for both dewa leaves and temu ireng rhizome. Extracts were given orally to the tested animals for seven continuous days. The number of trombocytes, erythrocytes, and hematocrites level were examine at day 7 using sysmex XE-5000 hematology analyzer. The result showed that the rat groups which were treated with dewa leaves extract at 500 mg/kgBW; temu ireng Rhizomes extract at 250 mg/kgBW and 500 mg/kgBW dosages had significant differences (α = 0.05) on number of thrombocytes. The percentages of thrombocytes number enhancement for temu ireng rhizomes extract 500 mg/kgBW, temu ireng rhizomes extract 250 mg/kgBW, dewa leaves extract 500 mg/kgBW were 26.98%, 24.48%, 19.44% respectively. The rats group which were treated with temu ireng Rhizomes extract at 500 mg/kgBW, dewa leaves extract at 250 mg/kgBW and 500 mg/kgBW had significant differences (α = 0.05) on erythrocytes number and hematocrits level enhancement. The percentages of erythrocytes number enhancement for dewa leaves extract at dose of 500 mg/kgBW and 250 mg/kgBW, temu ireng rhizomes extract 500 mg/kgBW were 9.59%, 9.11%, 9.02% respectively. The highest percentages of hematocrits level enhancement was given by dewa leaves extract at dose of 500 mg/kgBW (10,97%), suggesting that the extracts treatment would not trigger plasma leakage. Thus, dewa leaves extract at 500 mg/kgBW; temu ireng rhizomes extract at 250 mg/kgBW and 500 mg/kgBW dosages are potential as candidates to be medicinal herbs to increase numbers of thrombocytes on dengue fever treatment  相似文献   

18.
Density and ultrasound speed were measured accurately for diglycine + water, triglycine + water, diglycine + water-polyethylene glycol 400 (PEG400) and triglycine + water-PEG400 solutions at T = (293.15, 298.15, 303.15 and 308.15) K. The results were used in evaluating thermodynamic properties as apparent molar volumes (VØ) and apparent molar isentropic compressions (K) of diglycine and triglycine in water and in PEG400 solutions. Infinite dilution values of these parameters, VoØ, and Ko, were obtained from their plots as a function of molality by extrapolation and have been utilized in obtaining transfer volumes and transfer compressions at infinite dilution. All transfer volumes and transfer compressions were found to increase with increasing molality of PEG400. Apparent molar isobaric expansions were derived from the temperature dependence of VØ values at infinite dilution and at finite concentrations. All the results were interpreted in terms of solute (diglycine or triglycine) and co-solute (PEG400) and solvent (H2O) interactions.  相似文献   

19.
A study of the possibilities of pyrolysis for recovering wastes of the rope's industry has been carried out. The pyrolysis of this lignocellulosic residue started at 250 °C, with the main region of decomposition occurring at temperatures between 300 and 350 °C. As the reaction temperature increased, the yields of pyrolyzed gas and oil increased, yielding 22 wt.% of a carbonaceous residue, 50 wt.% tars and a gas fraction at 800 °C. The chemical composition and textural characterization of the chars obtained at various temperatures confirmed that even if most decomposition occurs at 400 °C, there are some pyrolytic reactions still going on above 550 °C. The different pyrolysis fractions were analyzed by GC–MS; the produced oil was rich in hydrocarbons and alcohols. On the other hand, the gas fraction is mainly composed of CO2, CO and CH4. Finally, the carbonaceous solid residue (char) displayed porous features, with a more developed porous structure as the pyrolysis temperature increased.  相似文献   

20.
Asymmetric polyimide membranes were fabricated from casting solution of 18 wt% polyamic acid and 1.3–20 wt% additive agent in dimethylacetamide at 343 K, with 1 min evaporation time, followed by a cyclization process of thermal treatment in a bath of dioctyl sebacate under N2 in three steps: 1 h at 373 K, 1 h at 473 K, 1 h at 573 K. The effect of additive agents and their quantity on the molecular weight cut-off (MWCO) performance of the asymmetric aromatic polyimide membrane were examined. By changing a sort of additive agents, the MWCO of the fabricated aromatic polyimide asymmetric membranes can be adjusted in the range of 400–650 daltons. By changing amount of additive agents, MWCO of the fabricated aromatic polyimide asymmetric membranes remain almost constant at the value of approximately 400 daltons for pyrene, and increased from 500–650 daltons for polystyrene.  相似文献   

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