Hours Of Soaking Research Articles

TESTES DE CONDUTIVIDADE ELÉTRICA PARA AVALIAÇÃO DO VIGOR DE SEMENTES DE SOJA (Glycine max (L.) Merrill)

O presente trabalho teve como objetivo investigar a possibilidade de redução do período de condicionamento das sementes nos testes de condutividade elétrica, nos sistemas de massa e individual, e consequentemente, obter indicações mais rápidas sobre a qualidade fisiológica dos lotes. Para tanto, foram utilizados quatro lotes de sementes de soja das variedades IAC-8 e IAC-15 que foram submetidos a estudos específicos de condutividade elétrica de massa e individual (ASA-610), empregando-se períodos de condicionamento de 4, 8, 12, 16, 20 e 24 horas. No sistema de massa foram utilizadas amostras de sementes não danificadas e de sementes fisicamente puras. Nos estudos com o ASA-610 foram testadas as intensidades de corrente elétrica de 95 a 45 mA/semente, em intervalos de 5mA. Além destes foram conduzidos os seguintes testes: germinação, primeira contagem de germinação, envelhecimento artificial e determinação do grau de umidade das sementes. Os resultados indicaram que há possibilidade de redução no período de condicionamento das sementes no teste de condutividade de massa, sendo que os períodos de embebição mais curtos (4 e 8 horas) permitiram a identificação de diferenças mais acentuadas entre os lotes, enquanto que leituras realizadas a partir de 16 horas mostraram-se mais sensíveis às variações de vigor das sementes. O referido teste mostrou-se adequado para a identificação de lotes com diferentes níveis de vigor. Já a condutividade individual (ASA-610) revelou eficiência variável de acordo com a variedade avaliada.

A comparison of two post-casting treatment methods for perfluorosulfonated ionomer films

The resultant effect of two post-casting treatments on the anion-rejection characteristics and adherence to a smooth Pt electrode of a perfluorosulfonate ionomer (Nafion) cast as a thin film (4 μm) from the commercially available alcohol solution is reported. The cyclic voltammetry of ferricyanide from both an acidic and neutral pH solution (2 mM sodium ferricyanide +0.2 M sulfuric acid and 50 mM sodium ferricyanide +0.2 M sodium sulfate, respectively) is used as the measure of anion rejection. Unannealed films which are cured at room temperature serve as the reference and are most permeable to ferricyanide in comparison to high-temperature (170 °C), vacuum-annealed films (20mm Hg) or films which are cured in a low-humidity environment at room temperature under 20mm Hg vacuum (drycured film). For example, after seventy hours of soaking in the neutral pH solution, the amount of ferricyanide absorbed in the unannealed film increased 390% above that after one hour. The dry-cured film, in comparison, absorbed less ferricyanide after one hour; but after seventy hours, even though the amount absorbed was still less than that in the unannealed film, the increase was 1300% above the amount after one hour. In contrast, the thermal-annealed film showed no measurable absorption of ferricyanide even after seventy hours of exposure. All films absorbed ferricyanide from the acidic solution but the thermal-annealed film exhibited the lowest amount. Thermal annealing results in the most stable film of the three: After 16 hours of exposure to 6 M sulfuric acid, the thermal-annealed film adhered to the platinum disk upon rotation, but the other two were sheared off the surface.

ACC-derived Ethylene Production, a Sensitive Test for Seed Vigor

ACC-derived ethylene production was used as an index of seed vigor of lettuce (Lactuca sativa L.), cabbage [Brassica oleracea (Capitata Group)], tomato (Lycopersicon esculentum Mill.), snap bean (Phaseolus vulgaris L.), and sweet corn (Zea mays L.) seeds. Seeds were aged at 40C and 93% relative humidity over saturated solution of KH2PO4 for various times to obtain seeds of differing vigor. Naturally aged lettuce seeds, differing in vigor, were also used. Depending on the seed type, 0.25 to 2 mm ACC (saturating dose) was needed to produce maximal amounts of ethylene. Seeds in the presence of ACC produced a much larger amount of ethylene than those in the absence of ACC, the ACC-derived ethylene could be detected before germination, and ACC had no adverse effect on germination. ACC-derived ethylene production paralleled vigor loss as determined by a decrease in percentage germination over a soak period required for complete germination of nonaged seeds (16 hours for lettuce, 24 hours for cabbage, and 48 hours for tomato and sweet corn), an increase in mean germination time (determined for lettuce only), and a decrease in seedling growth (determined for snap bean only). Second degree polynomial and logarithmic equations generated for the relationship of ACC-derived ethylene production to germination or growth parameters following seed aging, provided good to excellent fit. As a vigor test, the ACC-ethylene procedure has several advantages over the non-ACC ethylene procedure: It improves the sensitivity of the test by enhancing ethylene production, permits detection of small differences in vigor, and allows detection of ethylene before germination within a few hours of soaking. Chemical name used: 1-aminocyclopropane-1-carboxylic acid (ACC).

339 ACC-DERIVED ETHYLENE PRODUCTION, A RAPID TEST FOR SEED VIGOR

1-aminocyclopropane-1-carboxylic acid (ACC) was used to measure seed vigor of lettuce, cabbage, tomato, snap bean and sweet corn seeds. Accelerated aging at 40C and 93% RH over saturated solution of KH2PO4 and natural aging under ambient storage conditions (5-7C, 28 to 60% RH) were used to obtain seeds of differing vigor levels. Depending on the type of seeds, the amount of ACC needed for maximal ethylene production (saturating dose) ranged from 0.25 to 2mM. Seeds produced much larger amounts of ethylene in the presence than in absence of ACC, the ACC-derived ethylene was detected prior to germination, and ACC had no adverse effect on germination. ACC-derived ethylene production paralleled vigor loss as determined by percentage germination, mean germination time (for lettuce only) and seedling growth (for snap bean only). Second degree polynomial and logarithmic equations generated for the relationship of ACC-derived ethylene production to germination or growth parameters following seed aging, provided good to excellent fit. As a vigor test, the ACC-ethylene procedure has several advantages over the non-ACC ethylene procedure: it greatly improves the sensitivity of the test by enhancing ethylene production, it permits detection of small differences in vigor levels and it allows detection of ethylene prior to germination within a few hours of soaking.

Behaviour of the superconductivity characteristics of the Bi system during water soaking

Samples of a bulk Bi-Pb-Sr-Ca-Cu-O system and a thick film of the Bi-Sr-Ca-Cu-O system are soaked in distilled water and the change in the superconductivity characteristics is measured. For the bulk samples, the maximum magnetization in the magnetization curve and the critical current density increase for the first 18 hours of soaking and then decrease during the subsequent soaking time. The critical temperature shows monotonic decrease throughout the soaking. A thick-film sample is almost the same as a bulk sample, i.e. the critical current density of the thick film first tends to increase for a short time due to its greater surface area then tends to decrease during the subsequent soaking. The critical temperature of the film sample also shows a slight deterioration as a result of the water soaking.

Rate of elution of leachable components from composite

The uptake of solvent and the elution of molecules from a dental composite and an unfilled resin were monitored with time during soaking in either water or an ethanol/water mixture. The results showed that approximately 50% of the leachable species were eluted from the composite within three hours of soaking in water, while 75% of the leachable molecules were eluted into the ethanol/water mixture. Elution of nearly all of the leachable components was complete within a 24-hour period in either solvent. The study lends support to the view that dental composites do not provide a chronic source of unreacted monomer to the pulp or other oral tissues, due to a rapid and complete elution of the molecules.

2‐Amino‐3‐(methylamino)‐propanoic acid (BMAA) in cycad flour

We conducted an investigation of the levels of the neurotoxin 2-amino-3-(methylamino)-propanoic acid (BMAA) in cycad flour. Analysis of 30 flour samples processed from the endosperm of Cycas circinalis seeds collected on Guam indicated that more than 87% of the total BMAA content was removed during processing. Furthermore, in 1/2 the samples almost all (greater than 99%) of the total BMAA was removed. We found no significant regional differences in the BMAA content of flour prepared from cycad seeds collected from several villages on Guam. Testing of different samples prepared by the same Chamorro woman over 2 years suggests that the washing procedure probably varies in thoroughness from preparation to preparation but is routinely efficient in removing at least 85% of the total BMAA from all batches. Analysis of a flour sample that had undergone only 24 hours of soaking indicated that this single wash removed 90% of the total BMAA. We conclude that processed cycad flour as prepared by the Chamorros of Guam and Rota contains extremely low levels of BMAA, which are in the order of only 0.005% by weight (mean values for all samples). Thus, even when cycad flour is a dietary staple and eaten regularly, it seems unlikely that these low levels could cause the delayed and widespread neurofibrillary degeneration of nerve cells observed in amyotrophic lateral sclerosis and the parkinsonism-dementia complex of Guam (ALS-PD).

Treatment of Sorghum Grains with Calcium Hydroxide for Calcium Enrichment

Four varieties of sorghum grain (SB-1079, DSH-1, CSH-5, and SB-905) were subjected to four methods of treatment with saturated calcium hydroxide solution (soaking and drying with and without washing for germinated and ungerminated grains) for five different periods: dipping only, or 4, 8, 16, or 32 hours of soaking. Among all the varieties, treated germinated grain showed a higher calcium content than treated ungerminated grain. Irrespective of the method or duration of soaking, SB-905 showed a significantly lower calcium content than the other varieties. A maximum calcium content of 253.6 mg per 100 g of grain was obtained in the DSH-1 variety when germinated grain was soaked and dried, compared to a 55.0 mg per 100 g in the untreated sample. Washing after soaking resulted in a decreased calcium content in both germinated and ungerminated grains. Increasing the soaking time from simple dipping to four or eight hours resulted in a significant increase in calcium content. Further increases in soaking time to 16 or 32 hours caused a significant reduction in calcium content.

Alteration In Heavy Oil Characteristics During Thermal Recovery

Abstract Significant visbreaking, or a permanent reduction in viscosity of heavy oils, can occur during in-situ thermal recovery processes such as steamflooding and combustion. This paper reports a study on the mechanism of in-situ visbreaking. Isothermal visbreaking studies were conducted af 572 °F (300 °C) for up to 480 hours using heavy crudes from San Ardo, Celtic, and Cold Lake. The viscosity of the oil, as well as asphaltene content, distillation, elemental analysis, etc., were monitored as a function of time. The experimental results showed a permanent reduction in oil viscosity by a factor as high as ten, without significant formation coke, after 120 hours of soaking. The observed initial rate of viscosity reduction increases with increasing hydrogen content of the oil. Heavy oil is viewed as a colloidal system containing asphaltenes dispersed in a solvent phase commonly known as maltenes. Under this framework, visbreaking is interpreted as being caused by one of these three factors: a decrease in maltene viscosity, a reduction in asphaltene content, or a decrease in a third parameter called "reduced specific viscosity ", which characterizes the "solvent power " of the maltenes with respect to the asphaltenes. The decrease in maltene viscosity and the increase in its solvent power dominate the visbreaking mechanism. The effect of reduction in asphaltene content on visbreaking is relatively minor. Introduction High viscosity is a major constraint in the production and processing of heavy oils and oil sand bitumens. Thermal recovery processes employing steam or combustion are effective in temporarily lowering the oil viscosity and enhancing its production. Field evidence indicates that a permanent reduction in viscosity or "visbreaking " can accompany these processes which can result in partial upgrading of the heavy oil(1). In-situ visbreaking is characterized as a mild thermal cracking with the retention of products in the liquid phase. The extent of vis breaking depends upon the temperature, heating time, and the oil characteristics. Visbreaking as a recovery mechanism during steam recovery processes has been studied by Shu and Hartman(1) using numerical simulations. Their analysis showed that heavy oil visbreaking could have a significant effect on oil production depending upon the mode of steam process and the reservoir characteristics. The present work reports a study on the alteration in the oil characteristics during visbreaking for heavy crudes from San Ardo (California), Celtic (Saskatchewan), and Cold Lake (Alberta). Isothermal visbreaking experiments were conducted at 300 °C for up to 480 hours. Such information will be useful for numerical simulation studies, for evaluation of field data, for developing improved processes, and for designing surface upgrading facilities. Background Extensive information is available on the surface visbreaking of heavy oils and petroleum residue in the refining literature. In such studies, thermal cracking of the feed oil is carried out at a high temperature (near 450 °C) for short contact time (usually in seconds and minutes). On the contrary, during in-situ visbreaking, the reservoir oil is exposed to lower temperatures (200 – 325 °C) for longer periods of time (usually days and months). Few laboratory studies simulating the in-situ visbreaking conditions have been reported.

Acid Scarification and Protein Synthesis during Seed Germination1

AbstractIndian ricegrass [Oryzopsis hymenoides (Roem. and Schult.) Ricker] seeds exhibit an intense seed coat dormancy which is relieved by acid scarification. This study examined the influence of exogenous hormonal compounds, gibberellin A3 (GA3) and abscisic acid (ABA) and acid scarification on the early protein synthesis of these seeds. Hormonal applications failed to alter 14C‐leucine incorporation or to change the levels of amino acid pool size or soluble protein during the first 72 hours of soaking of intact seeds. However, GA3 enhanced while ABA lowered the amino acid and soluble protein levels in scarified seeds. The incorporation of relatively large amounts of 14C‐leucine into proteins occurred at 24 hours after soaking in intact seeds while no increase was detected in scarified seeds until 48 hours, a period when germination had already occurred. Soluble proteins were reduced 60 % following acid scarification compared to intact seeds and seed exudates increased with increased scarification time. These results demonstrate a profound effect of acid scarification on the seed which is manifested by delayed protein synthesis, reduced protein level, and increased leaching of electrolytes.

Vibratome Sections Of Difficult Tissues

After 1 hours of aldehyde fixation, 4 to 20 hours of soaking in 2% BSA (bovine serum albumin) solution and another 17 hours in the same fixative, the vibratome will produce smooth, even sections from agar embedded guinea pig thyroid, skeletal muscle or larynx with the same ease as it will from soft, homogeneous tissues such as liver or spleen.

Control of Enzyme Activities in Cotton Cotyledons during Maturation and Germination

Actinomycin D at 10 mug/ml strongly inhibited the increase in isocitrate lyase activity during germination of seeds and 40-day-old embryos of cotton (Gossypium hirsutum L.) when the germination period was preceded by 3 hours of soaking in the inhibitor solution. No inhibition was observed without the presoaking. Induction of nitrate reductase activity by nitrate was never inhibited by actinomycin D under the same conditions, and was frequently stimulated about 50%. Thus, the method of applying actinomycin D to the seeds and ovules could affect interpretation of its action. Abscisic acid at 5 mug/ml blocked production of isocitrate lyase activity in both pregermination treatments, but did not inhibit induction of nitrate reductase activity. Induction of nitrate reductase activity became insensitive to the two inhibitors during ovule maturation, at about 32 days after anthesis. The results indicate that isocitrate lyase, a germination enzyme, is not synthesized on performed mRNA. In this respect, the appearance of activity in cotton resembles that in other species of fatty seeds. In contrast, induction of nitrate reductase activity, which is unnecessary for germination, apparently is not regulated at the level of transcription except in young ovules.

Occurrence of Some Enzymes in Starchy Endosperm and Hormonal Regulation of Isoperoxidase in Aleurone of Wheat

Peroxidase, indoleacetic acid-oxidase, alkaline, and acid phosphatases were detected in dry starchy endosperm (minus aleurone) of wheat grain. The isoperoxidase pattern differed in different parts of the dry grain. Several new isoperoxidases were found in embryos after soaking. The intensity of isoperoxidases in aleurones was enhanced in the presence of embryo or 2 muM GA(3) after 24 hours of soaking, but decreased after 72 hours. Indoleacetic acid and kinetin had no effect on isoperoxidase of aleurone. Actinomycin D and cycloheximide had no effect on isoperoxidases of aleurones from embryonectomized or naturally occurring embryoless grains. However, these two inhibitors increased the intensity of isoperoxidases in aleurones of intact embryonated grains after soaking.

Embryoless Wheat Grain

Yorkstar wheat, grown in New York State, has a high percentage (10-11) of grains without embryos. The embryoless grains have viable aleurone layers and show no sign of injury. These grains are able to support alpha-amylase synthesis only in the presence of gibberellin A(3) (GA(3)). In the absence of GA(3) some protein synthesis occurs in embryoless grains during the early hours of soaking, indicating that such activity occurs prior to and independent of GA(3) induction of alpha-amylase. The level of beta-amylase on a dry weight basis is the same in embryoless and normal grains and decreases with time of soaking. In the presence of GA(3), beta-amylase decreases at a slower rate. Isoenzymes of alpha-amylase from GA(3)-treated embryoless and normal grains show quantitative as well as qualitative differences. Cycloheximide (60 mug/ml) completely inhibits the synthesis of alpha-amylase by embryoless grains. Of the RNA synthesis inhibitors, actinomycin D (60 mug/ml) was ineffective while 6-methylpurine (60 mug/ml) gave 65% inhibition without decreasing the number of isoenzymes.

Variation of delta ferrite in steel 1Kh16N4B in homogenization

1. The structure of cast steel 1Kh16N4B contains δ-ferrite of angular shape which reduces its properties. 2. It is possible to reduce the quantity of δ-ferrite by heating and soaking at 900–1300°C, whereby polymorphous α→γ transformation takes place. 3. The higher the temperature, the more intensively the quantity of δ-ferrite is reduced. peratures above 1200°C the decrease is observed during the first hours of soaking and then the quantity of δ-ferrite increases as a result of polymorphous γ→α transformation. 4. The possibility of reducing the quantity of δ-ferrite indicates that the formation of δ-ferrite in the cast steel 1Kh16N4B is preserved as a result of liquation.

Imbibition and Germination: Influence of Hard Seed Coats on RNA Metabolism

AbstractRNA metabolism of Indian rice grass seeds was studied in relation to imbibition and germination. These seeds germinate only after scarification of the seed coats. The hard seed coats restrict germination but not water intake or changes in the quantity and quality of RNA formed during early hours of soaking. These changes differ markedly from those in scarified (H2SO4 treated) seeds which are able to germinate. Gibberellic acid hastens germination of scarified seeds and causes changes in the population of RNA transcribed.

Changements de l'ultrastructure des cellules radiculaires de Zea mays au d�but de la germination

The ultrastructure of root cells of the germinating corn embryo has been studied during the first 72 hours of soaking. The most spectacular ultrastructural modifications occur in the nucleus. In the dry seed, the chromatin is heavily condensed and complete dispersion occurs during the first 8 hr of germination. The nucleolus appears as a compact structure in the dormant embryo, and as a uniform granular structure after 3 hr. At the 8th hour, large nucleolar vacuoles appear filled with material structurally similar to chromatin. Later on, the nucleolus is composed of a central, fibrillo-granular region surrounded by a thin, peripheral, granular region and fewer nucleolar vacuoles are found. In a previous autoradiographic study (Deltour, 1970), it was shown that the onset of RNA synthesis in these cells occurs 4 hr after soaking. From that time to the 8th hour, uridine-3H is incorporated exclusively into the chromatin. Incorporation of radioactive uridine into the nucleolus begins only after the 8th hour. It is interesting that the onset of RNA synthesis in the chromatin occurs simultaneously with the dispersion of this cell component, and that the appearance of vacuoles in the nucleolus is correlated with the beginning if uridine incorporation into this organelle. The following ultrastructural changes take place in the cytoplasm; (a) the lamellae system of proplastids increases slightly; (b) phytoferritin granules present in the proplastids of the dry seed disappear very rapidly; (c) polysomes appear 72 hr after soaking; (d) the spherosomes which are essentially localized in the vicinity of the wall in the dormant embryo become uniformly distributed throughout the cytoplasm at the 72nd hr.

Treatments of southern pine with vinyl chloride and methyl methacrylate for radiation-produced wood-plastic combinations

A method was developed for the impregnation of liquid vinyl chloride monomer into wood. Wood-plastic combinations (WPC) prepared from polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), and polyvinyl chloride plasticized with diocylthalate (DOP+PVC) were found to offer improvements in selected physical properties of wood. The initial anti-swell efficiency (ASE) values of PMMA WPC and DOP+PVC WPC are very high, averaging approximately 87 and 82 percent respectively after 5 hours of soaking; whereas PVC WPC attained an average of only 53 percent. After prolonged soaking, the ASE values of all treated wood decreased considerably, indicating no permanent stability was achieved. In hardness, the PMMA WPC attained an average springwood-summerwood rating of 76, the DOP+PVC WPC and the PVC WPC a rating of 69 and 63, respectively; whereas the untreated wood achieved a rating of only 53.

Hydrogen Metabolism in Higher Plants

Kinetin interacts with light in the promotion of the germination of Grand Rapids lettuce seeds. In the dark, there is only a slight stimulating effect. The optimal condition for the study of this interaction was the use of very small quantities of light given after 7 hours of soaking. Kinetin modified neither the germination rate of the seeds nor the general time course of germination. Kinetin was given as late as 8 hours after illumination and still showed the maximum interaction with light. The seeds showed a maximum sensitivity to kinetin between the fifth and seventh hours after the beginning of imbibition. At this moment of the time course, a soaking of 5 minutes in kinetin is sufficient to induce the interaction with light. The contradictory results found previously on the action of kinetin on seeds soaked in the dark are due to the different photosensitivity of the seed lots.

Radiosensitivity of Seeds: II. Effects of Soaking, Storage, and Gamma Rays

ABS>Barley grains received Co/sup 6/⁰ gamma rays after various periods of aerobic soaking and storage. Treatment combinations totaled 126 and were replicated four times. Effects were measured by germination and seedling height, 11 days from the start of treatment. Soaking without irradiation caused no significant injury unless prolonged for 24 hours. In the 10,000-r treatments, with 1 to 4 hours of soaking, sensitivity increased until 7 hours' preirradiation storage and decreased with longer storage periods. Similar changes of sensitivity occurred in the 2000-r treatments after longer periods of soaking and storage. The spectacular decline of sensitivity during storage in these instances was attributed to interruption of the rapid increase in metabolic rate as water became limiting. (auth)