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Inibidor da ação do etileno na conservação pós-colheita de Chrysanthemum morifolium Ramat cv. Dragon

Spricigo, Poliana Cristina; Mattiuz, Ben-Hur; Pietro, Júlia de; Mattiuz, Claudia Fabrino Machado; Oliveira, Maria Elisa Morais de
Fonte: Editora da Universidade Federal de Lavras (UFLA) Publicador: Editora da Universidade Federal de Lavras (UFLA)
Tipo: Artigo de Revista Científica Formato: 1184-1190
POR
Relevância na Pesquisa
46.57%
A durabilidade e a qualidade pós-colheita de flores de corte são atributos fundamentais na sua valoração ao longo da cadeia produtiva e na satisfação dos consumidores. Objetivou-se, nesta pesquisa, verificar o efeito do tiossulfato de prata, associado ou não à sacarose, na manutenção da qualidade pós-colheita de hastes de crisântemos (Chrysanthemum morifolium Ramat cv. Dragon) . O experimento foi conduzido sob delineamento inteiramente casualizado, em esquema fatorial testando soluções de manutenção com tiossulfato de prata (STS), sob cinco níveis (Água destilada; STS a 0,2 mM; STS a 0,2 mM + sacarose a 50 g L-1; STS a 0,4 mM; STS a 0,4 mM + sacarose a 50 g L-1); e data de amostragem, por três níveis (0; 3; 6 dias). Utilizaram-se três repetições com duas hastes florais em cada tratamento. Foram feitas avaliações físicas: coloração, massa fresca e conteúdo relativo de água (CRA); avaliações químicas: açúcares redutores e pigmentos; e avaliações qualitativas: turgescência, cor das flores, e número de botões, flores entreabertas e abertas. O tratamento com 0,2 mM de STS possibilitou melhor manutenção da massa fresca das hastes. A concentração de pigmentos e carboidratos redutores foi maior naqueles tratamentos em que a sacarose foi associada. A coloração e o conteúdo relativo de água foram favorecidos nos tratamentos STS a 0...

Gray mold severity and vase life of rose buds after pulsing with citric acid, salicylic acid, calcium sulfate, sucrose and silver thiosulfate

Capdeville,Guy de; Maffia,Luiz A.; Finger,Fernando L.; Batista,Ulisses G.
Fonte: Sociedade Brasileira de Fitopatologia Publicador: Sociedade Brasileira de Fitopatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2003 EN
Relevância na Pesquisa
66.79%
Gray mold of roses (Rosa hibrida) caused by Botrytis cinerea requires many management strategies for its control. The effect of pulsing rose cv. Kiss with solutions of citric acid, salicylic acid, sucrose, calcium sulfate, and silver thiosulfate (STS) on disease severity and vase life of the flowers was evaluated. The solutions were applied to cut stems at different stages of harvest, the variation in the opening stage of harvest did not affect the results. Pulsing with STS reduced the values of area under the disease progress curve (AUDPC) and of severity of disease by 15% and 55%, respectively, and increased the vase life of the flowers by 20%. Calcium sulfate consistently reduced AUDPC by 66% and maximum severity by 88%, and increased vase life of the flowers by 37%. Therefore, pulsing rose buds with solutions of STS and calcium sulfate is potentially useful in reducing losses due to gray mold after harvest and in extending the vase life.

Formation of dense cellulose monolayers on silver surfaces

Soo,Whan Choi; Lauer,Heike; Wenz,Gerhard; Bruns,Michael; Petri,Denise F. S.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2000 EN
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26.55%
The adsorption of a new cellulose derivative,6-O-(2,3-bis(thiosulfato) propyl-oxy-2-hydroxy-propyl)-cellulose (TSHP), onto silver surfaces was investigated by means of ellipsometry, contact angle measurements and X-ray photoelectron spectroscopy (XPS). The results showed that the formation of a dense TSHP monolayer on silver surfaces is an irreversible and slow process. Based on XPS results a model was proposed to explain the chemisorption of TSHP on silver substrates. This model considers the homolytical cleavage of the thiosulfate groups attached to the cellulose chains with the formation of thio radicals, which bind covalently to the silver surface. The formation of silver thiolates lead to a stable TSHP monolayer on silver surfaces.

Leaching of gold and silver from printed circuit board of mobile phones

Petter,Patrícia Melo Halmenschlager; Veit,Hugo Marcelo; Bernardes,Andréa Moura
Fonte: Escola de Minas Publicador: Escola de Minas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
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36.79%
Nowadays there is a wide variety of models, sizes and configurations of mobile phones available for consumption. After the life cycle of this equipment, the recycling and reuse of the precious metals found in the printed circuit boards (PCB) of the mobile phones are principal objectives. Thus, the objective of this work was to characterize the gold and silver present in a PCB and develop a recycling route using alternative reagents for cyanide, such as sodium and ammonium thiosulfate. These reagents are less harmful to the environment and worker health. The first characterization of gold and silver was performed with aqua regia. The results show 86.26g Au/ton of PCBs and 123.85g Ag/ton of PCBs. The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a cyanide-based reagent.

Factors Affecting Oxidation of Thiosalts by Thiobacilli

Silver, M.; Dinardo, O.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1981 EN
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26.83%
The effects of temperature, initial pH, and the concentrations of ammonium, phosphate, and heavy metals on the oxidation of thiosalts by an authentic strain of Thiobacillus thiooxidans (ATCC 8085) and by a mixed culture isolated from a base metal-processing mill effluent pond were studied. The optimum temperature was 30°C and the optimum initial pH was 3.75 for both cultures using thiosulfate and for the mixed culture using tetrathionate. T. thiooxidans ATCC 8085 did not oxidize tetrathionate. For a thiosalt concentration of 2,000 ppm (2,000 mg/liter), maximal rates of destruction occurred at concentrations of ammonium ion above 2 mg/liter and in the presence of 1 mg of phosphate per liter. Under optimal conditions, the rate of thiosulfate oxidation by the pure culture was 55 ± 3 mg/liter per h; the mixed culture oxidized thiosulfate at the rate of 40 ± 1 mg/liter per h and tetrathionate at the rate of 50 ± 2 mg/liter per h. Metal ions caused normal inhibition kinetics in the oxidation of thiosulfate by T. thiooxidans ATCC 8085. Ki values were calculated for cadmium (16 mg/liter), copper (0.46 mg/liter), lead (2 mg/liter), silver (3.1 mg/liter), and zinc (33 mg/liter). Only a slight additive effect was apparent in the presence of all of these metal ions. The mixed culture of thiosalt-oxidizing bacteria was less sensitive to heavy metal inhibition; the order of inhibition of thiosulfate oxidation was Cd < Zn < Pb < Ag < Cu...

Effect of Silver Ions on Ethylene Biosynthesis by Tomato Fruit Tissue 1

Atta-Aly, Mordy A.; Saltveit, Mikal E.; Hobson, Graeme E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1987 EN
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36.58%
Mature-green tomato fruit (Lycopersicon esculentum Mill.) were treated asymmetrically with 2 millimolar silver thiosulfate (STS) through a cut portion of the peduncle while still attached to the plant. One-half of the fruit received silver and remained green while the other half ripened normally and was silver-free (less than 0.01 parts per billion). Harvested mature-green fruit were also treated with STS through the cut pedicel. Green tissue from silver-treated fruit had levels of 1-aminocyclopropane-1-carboxylic acid (ACC, the immediate ethylene precursor) slightly less or similar to that of turning or red-ripe tissue from the same fruit, and similar to that of mature-green tissue from control fruit. Ethylene production was higher in green tissue from silver-treated fruit than from either red tissue from the same fruit, or mature-green tissue from control fruit. By inhibiting ACC synthesis with aminoethoxyvinyl glycine, and by applying ACC ± silver to excised disks of pericarp tissue from control or silver-treated tomatoes, we showed that short-term silver treatment did not affect the biological conversion of ACC to ethylene, while long-term treatment stimulated both the conversion of ACC to ethylene and the synthesis of ACC.

Molecular Cloning and Characterization of Senescence-Related Genes from Carnation Flower Petals 1

Lawton, Kay A.; Huang, Bin; Goldsbrough, Peter B.; Woodson, William R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1989 EN
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The senescence of carnation (Dianthus caryophyllus L.) flower petals is associated with increased production of ethylene which plays an important role in regulating this developmental event. Three senescence-related cDNA clones were isolated from a cDNA library prepared from mRNA isolated from senescing petals. These cDNAs are representative of two classes of mRNAs which increase in abundance in senescing petal tissue. The mRNA for one class is present at low levels during the early stages of development and begins to accumulate in mature petals prior to the increase in ethylene production. The accumulation of this mRNA is reduced, but not eliminated, in petals treated with aminooxyacetic acid, an inhibitor of ethylene biosynthesis, or silver thiosulfate, an ethylene action inhibitor. In contrast, expression of the second class of mRNAs appears to be highly regulated by ethylene. These mRNAs are not detectable prior to the rise in ethylene production and increase in abundance in parallel with the ethylene climacteric. Furthermore, expression of these mRNAs is significantly inhibited by both aminooxyacetic acid and silver thiosulfate. Expression of these mRNAs in vegetative and floral organs was limited to floral tissue, and predominantly to senescing petals.

Effect of Ethylene Action Inhibitors upon Wound-Induced Gene Expression in Tomato Pericarp 1

Henstrand, John M.; Handa, Avtar K.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1989 EN
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26.57%
The contribution of wound-ethylene to wound-induced gene expression was investigated in unripe tomato pericarp using inhibitors of ethylene action. Wounded unripe tomato pericarp was treated with 2,5-norbornadiene or silver thiosulfate to inhibit specifically the induction of ethylene-dependent mRNA species. Poly(A)+ RNAs isolated from these tissues after 12 hours of wounding were translated in vitro in a rabbit reticulocyte lysate system and [35S]methionine-labeled polypeptides were compared to unwounded controls after separation by one and two-dimensional polyacrylamide gel electrophoresis. Results show that mechanical wounding induces a dramatic shift in gene expression (over 50 mRNA species) but expression of less than 15% of these genes is affected by the treatment with ethylene action inhibitors. A selective decrease in mRNAs coding for a 37 kilodalton doublet and 75 kilodalton polypeptides is observed in 2,5-norbornadiene and silver thiosulfate treated wounded pericarp. Levels of hydroxyproline-rich glycoprotein mRNAs induced in wounded tissue were not influenced by inhibitors of ethylene action.

Role of Ethylene in the Senescence of Isolated Hibiscus Petals 1

Woodson, William R.; Hanchey, Susan H.; Chisholm, Duane N.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1985 EN
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26.57%
Senescence of petals isolated from flowers of Hibiscus rosa-sinensis L. (cv Pink Versicolor) was associated with increased ethylene production. Exposure to ethylene (10 microliters per liter) accelerated the onset of senescence, as indicated by petal in-rolling, and stimulated ethylene production. Senescence was also hastened by basal application of 1-aminocyclopropane-1-carboxylic acid (ACC). Aminooxyacetic acid, an inhibitor of ethylene biosynthesis, effectively inhibited ethylene production by petals and delayed petal in-rolling. In marked contrast to these results with mature petals, immature petals isolated from flowers the day before flower opening did not respond to ethylene in terms of an increase in ethylene production or petal in-rolling. Furthermore, treatment with silver thiosulfate the day before flower opening effectively prevented petal senescence, while silver thiosulfate treatment on the morning of flower opening was ineffective. Application of ACC to both immature and mature petals greatly stimulated ethylene production indicating the presence of an active ethylene-forming enzyme in both tissues. Immature petals contained less free ACC than mature, presenescent petals and appeared to possess a more active system for converting ACC into its conjugated form. Thus...

Kinetics of Maize Leaf Elongation 1: III. Silver Thiosulfate Increases the Yield Threshold of Salt-Stressed Plants, but Ethylene Is Not Involved

Cramer, Grant R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1992 EN
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46.57%
The involvement of ethylene in the short-term responses of maize (Zea mays L.) leaf elongation to salinity was investigated. Leaf elongation rates (LER) were monitored with linear variable differential transformers. Salinity (80 mm NaCl) rapidly inhibited LER. Pretreatment with 4 mm silver thiosulfate (STS), an inhibitor of ethylene action, decreased LER of salt-stressed plants, but not that of controls. Investigation of the growth parameters affected by the interaction of STS and salinity indicated that the yield threshold was increased and the cell wall extensibility was decreased. All other growth parameters controlling cell elongation were unaffected. Further investigation indicated that ethylene production may not be involved in this reponse because treatments with 10 μm aminoethoxyvinylglycine, an ethylene biosynthesis inhibitor, did not affect the growth of salt-stressed plants, and no increase in ethylene production was detected in salt-stressed plants compared with controls. No changes in sensitivity to ethylene were evident because LER of both control and salt-stressed plants were inhibited to the same extent with exposure to 1.2 ppm ethylene. The above evidence indicated that ethylene was not involved in the short-term LER responses of salt-stressed maize.

Ethylene Promotes Elongation Growth and Auxin Promotes Radial Growth in Ranunculus sceleratus Petioles 1

Smulders, Marinus J. M.; Horton, Roger F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1991 EN
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26.79%
Submergence induces elongation in the petioles of Ranunculus sceleratus L., after a rise in endogenous ethylene levels in the tissue. Petioles of isolated leaves also elongate 100% in 24 hours when treated with ethylene gas, without a change in the radius. Application of silver thiosulfate, aminoethoxyvinylglycine (AVG), abscisic acid (ABA), or methyl jasmonate inhibits this elongation response. Gibberellic acid treatment promotes ethylene-induced elongation, without an effect on the radius. Indoelastic acid (IAA) induces radial growth in the petioles, irrespective of the presence or absence of added ethylene. High concentrations of IAA will also induce elongation growth, but this is largely due to auxin-induced ethylene synthesis; treatment with silver thiosulfate, AVG, ABA, or methyl jasmonate inhibit this auxin-promoted elongation growth. However, the radial growth induced by IAA is not affected by gibberellic acid, and not specifically inhibited by ABA, methyl jasmonate, silver thiosulfate, or AVG. These results support the idea that petiole cell elongation during “accommodation growth” can be separated from radial expansion. The radial expansion may well be regulated by IAA. However, effects of high levels of IAA are probably anomalous...

Artifactual Sulfation of Silver-stained Proteins : Implications for the Assignment of Phosphorylation and Sulfation Sites *S⃞

Gharib, Marlene; Marcantonio, Maria; Lehmann, Sylvia G.; Courcelles, Mathieu; Meloche, Sylvain; Verreault, Alain; Thibault, Pierre
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
Publicado em /03/2009 EN
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26.91%
Sulfation and phosphorylation are post-translational modifications imparting an isobaric 80-Da addition on the side chain of serine, threonine, or tyrosine residues. These two post-translational modifications are often difficult to distinguish because of their similar MS fragmentation patterns. Targeted MS identification of these modifications in specific proteins commonly relies on their prior separation using gel electrophoresis and silver staining. In the present investigation, we report a potential pitfall in the interpretation of these modifications from silver-stained gels due to artifactual sulfation of serine, threonine, and tyrosine residues by sodium thiosulfate, a commonly used reagent that catalyzes the formation of metallic silver deposits onto proteins. Detailed MS analyses of gel-separated protein standards and Escherichia coli cell extracts indicated that several serine, threonine, and tyrosine residues were sulfated using silver staining protocols but not following Coomassie Blue staining. Sodium thiosulfate was identified as the reagent leading to this unexpected side reaction, and the degree of sulfation was correlated with increasing concentrations of thiosulfate up to 0.02%, which is typically used for silver staining. The significance of this artifact is discussed in the broader context of sulfation and phosphorylation site identification from in vivo and in vitro experiments.

Biologically incorporated dietary silver has no ionoregulatory effects in american red crayfish (procambarus clarkii)

Mann, Reinier; Grosell, Martin; Bianchini, Adalto; Wood, Chris
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.5%
Two silver-contaminated diets were prepared by exposing juvenile rainbow trout for 8 d to waterborne silver thiosulfate as Ag at either 0.1 mg/L (low-Ag diet) or 80 mg/L (high-Ag diet). The level of total Ag accumulated in whole low-Ag fish was below the detection limit of analysis. Whole high-Ag fish accumulated Ag at 21.3 nmol/g. The livers of the low- and high-Ag fish accumulated Ag at 0.43 nmol/g and 1.01 mmol/g, respectively. The Ag-contaminated fish were then fed whole to adult crayfish in an 80-d dietary study to determine the effects of long-term trophic accumulation of Ag. In a second experiment, the livers of the high-Ag trout were fed to juvenile crayfish for either one or five weeks. Accumulation of Ag was demonstrated in both adult and juvenile crayfish. Silver accumulation in juvenile crayfish peaked at approximately 650 nmol/g at three weeks, after which Ag depuration occurred. In adult crayfish that consumed the high-Ag diet, the hepatopancreas accumulated more than 90% of assimilated Ag, rising 1,000-fold over control animals to approximately 740 nmol/g at 80 d. Crayfish that consumed the low-Ag diet had small, statistically insignificant elevations of Ag in some tissues. Dietary Ag had no effect on juvenile crayfish growth or adult mortality. Disturbances in osmoregulation...

Improvement of silver impregnation technique (Protargol) to obtain morphological features of protists ciliates, flagellates and opalinates

SILVA-NETO,I. D. da
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2000 EN
Relevância na Pesquisa
26.46%
The research on ciliates, flagelates and opalinates have been widespread by the utilization of techniques employing silver impregnation (Protargol), modified by several authors. However, these are time consuming and its results are variable. The present work is a variant of the technique described by Tuffrau (1964, 1967) showing some adaptations made in our laboratory. The organisms can be preserved by different fixatives (alcoholic Bouin, Stieve's fluid, 2.5% glutaraldehyde and others) and then rinsed in destilled water followed by a fast clarification by 3% sodium hypochloride. If the organism is very sensitive to hypochloride, 4% sodium lauryl sulfate may be used and then washed 3 times in distilled water. The protista can be adhered to the glass slides with Mayer's glycerinated-albumin (1 glycerin vol. to 1 or 2 albumin vol.), diluted in water at a proportion of 1:10 Cv/v., or with 1% polylysine followed by fast washes with distilled water. After the slide preparation, they were covered with a layer of 0,8% Silver proteinate. Right after that, the slide has to be placed in a glass tray lined with moist tissue and covered to prevent the proteinate to dry. The tray was placed in a incubator at 40º-50ºC for 30 minutes. The slides are rinsed for 1 minute. with warm (35ºC) distilled water. The development of the material should be done with 0.4% hydroquinone with a maximum incubation time of 1 minute. It should be developed gradually...

Regulation of the gravitropic response and ethylene biosynthesis in gravistimulated snapdragon spikes by calcium chelators and ethylene inhibitors.

Philosoph-Hadas, S; Meir, S; Rosenberger, I; Halevy, A H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1996 EN
Relevância na Pesquisa
26.57%
The possible involvement of Ca2+ as a second messenger in snapdragon (Antirrhinum majus L.) shoot gravitropism, as well as the role of ethylene in this bending response, were analyzed in terms of stem curvature and gravity-induced asymmetric ethylene production rates, ethylene-related metabolites, and invertase activity across the stem. Application of Ca2+ chelators (ethylenediaminetetraacetic acid, trans-1,2-cyclohexane dinitro-N,N,N',N'-tetraacetic acid, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N',-tetraacetic acid) or a Ca2+ antagonist (LaCl3) to the spikes caused a significant loss of their gravitropic response following horizontal placement. Conversely, the Ca2+ ionophore A23187 or the agonist Bay K-8644 increased gravibending. Longitudinally halved stem sections had significantly higher amounts of ethylene, 1-aminocyclopropane-1-carboxylic acid, and 1-(malonylamino) cyclopropane-1-carboxylic acid compared with vertical controls, with the extra production arising exclusively from the lower half of the stem. trans-1,2-cyclohexane dinitro-N,N,N',N'-tetraacetic acid pretreatment completely abolished the gravity-induced ethylene gradient across the stem, thereby leading to a significant reduction of the curvature. Similarly, reduction of the ethylene produced in the gravistimulated with CoCl2 or inhibition of its action by silver thiosulfate or 2...

Nanoscale characterization of thin immersion silver coatings on copper substrates

Török, T. I.; Csik, A.; Hakl, J.; Vad, K.; Kövér, L.; Tóth, J.; Mészáros, S.; Kun, É.; Sós, D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/02/2015
Relevância na Pesquisa
26.78%
Microelectronic-grade copper foils were immersion silver plated in a home-made non-cyanide alkaline silver nitrate - thiosulfate solution and in two commercially available industrial baths via contact reductive precipitation. The concentration depth profiles of the freshly deposited silver layers were afterwards analyzed at nanoscale resolution by means of Secondary Neutral Mass Spectrometry (SNMS) and Glow Discharge Optical Emission Spectroscopy (GDOES). The thickness of deposited silver layers obtained with 30-60 s immersion time were in the range of 50-150 nm, depending on the parameters of the immersion procedure. Slight contamination of sulfur from the thiosulfate bath was detectable. Traces of Cr and Na could be observed as well around the interface between the copper substrate and silver deposit. Results also indicate that storage for longer time in air especially at higher than ambient temperatures induces a kind of ageing effect in the deposited layer, changing its composition. In case of samples prepared from home-made solution increasing amounts of copper together with its corrosion products became detectable.

The conservation of silver gelatin prints: research on the applicability of the methylene blue method for measuring residual thiosulfate and polythionates in aged photographs

Burgi, Sergio
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
26.41%
No abstract found.

Comparison of the development characteristics of a sodium thiosulfate monobath with that of a mercaptoacetic acid monobath

Smith, Richard
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
37.04%
The development characteristics of mercaptoacetic acid monobaths were compared with those of sodium thiosulfate monobaths at varying fixing-agent concentrations. The following differences were noted: (1) it required four times more moles-per-liter of sodium thiosulfate than metcaptoacetic acid to obtain the same rate of fixation; (2) the mercaptoacetic acid monobath produced less silver than the sodium thiosulfate; (3) KODAK Panatomic-X Film developed in a mercaptoacetic acid monobath had a covering power greater than or equal to that produced by development in the same phenidone-hydroquinone developer without any fixing agent, whereas the covering power of the sodium thiosulfate monobath was less; (4) the density growth of a mercaptoacetic acid monobath showed an initial sharp rise followed by a period of zero growth, whereas the sodium thiosulfate monobath showed a much longer and slower period of density growth; and (5) the time required for a mercaptoacetic acid monobath to reach its maximum density was independent of fixing-agent concentration, whereas that of a sodium thiosulfate monobath increased with decreasing fixing-agent concentration. It was concluded from the comparisons of the development characteristics of the two monobaths that the development of the mercaptoacetic acid monobath proceeded primarily by chemical development...

Effect of stabilizers on sulfur sensitization

Gingello, Anthony; MacIntyre, Gladys
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
26.5%
It has been repeatedly suggested that chemical sensitization by sulfur compounds depends not only on the formation of silver sulfide, but on its rearrangement on the grain surface to form sensitivity centers. The most direct evidence for this is that there is no sensitization on addition of soluble sulfide to the emulsion which forms silver sulfide, but, on heating the emulsion with the sulfide for a longer time and a higher temperature than those used for thiosulfate sensitization, equivalent sensitization can be obtained. Stabilizers such as 6-methyl-4-hydroxy-l,3,3a,7-tetraazaindene (TAI) , which stop photographic sensitization, do not stop the chemical reaction of silver sulfide formation. It has now been demonstrated that when TAI is added to the emulsion after formation of silver sulfide from a soluble sulfide, it prevents the sensitization on heating, and hence must stop rearrangement, l-phenyl-5-mercaptotetrazole retards sensitization when added after the sulfide is formed, but appears to act mainly as an antifoggant during development. Increasing the pAg also retarded the rate of sensitization but did not stop rearrangement.

Effect of Organic and Inorganic Silver Complexing Agents on Image Quality

Scharfstein, Stephen
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
26.41%
Image Quality of plus-x film processed in a monobath solution containing an inorganic silver complexing agent ( sodium thiosulfate ), was compared to plus-x film processed in an organic silver complexing agent ( mercaptoacetic acid ). A control run using DK-50 was also made. The image quality of the film was best with DK-50 and worst with mercaptoacetic acid. Image quality was determined by the results of the following tests: 1 ) Resolving Power 2 ) Acutance 3 ) MFT 4 ) Granularity