Significance Of pH Research Articles

Bioleaching of heavy metals from sediment: significance of pH

Bioleaching process, which causes acidification and solubilization of heavy metals, is one of the promising methods for removing heavy metals from contaminated sediments. The solubilization of heavy metals from contaminated sediments is governed by the sediment pH. In the present study, the significance of pH in bioleaching of heavy metals from contaminated sediment was evaluated at different solid contents of sediments in a bench-scale reactor. Results showed that a temporal change of pH in the bioleaching process was effected by the buffering capacity of the sediment particulates. The variations of pH in this bioleaching process were calculated by a modified logistic model. It was observed that solubilization of heavy metals from sediments is highly pH-dependent. In addition, a non-linear equation for metal solubilization relating pH value in the bioleaching process was established. This allows an easier and faster estimate of metal solubilization by measuring pH in the bioleaching process.

Possible significance of Ph, Zinc and BCR-ABL chimaerism in the pathogenesis of chronic myeloid leukaemia

Available evidence suggests a double-pathway two-staged genetic alteration in the pathogenesis of Chronic Myeloid Leukaemia (CML). The regular Ph' defect results in BCR-ABL gene chimaerism on the one hand and suppressed synthesis of the protein responsible for Zn absorption on the ether. The resulting Zn deficiency leads, through its metalloenzymes, to a low NAP activity and depressed DNA & RNA polymerase activities: the latter necessitates an adaptive mechanism to sustain cell division despite low zinc. This adaptation is in the form of another gene alteration; a point mutation in the BCR-ABL chimaeric gene, now an oncogene, whose onco-proteins are zinc-independent and stimulate cell division more efficiently (though abnormally also) than the polymerases while defying the usual mechanisms regulating DNA synthesis and cell division. Thus it seems possible that assisted transcellular zinc transport could prevent development of CML in Ph'-positive individuals and the enhanced (abnormal) cellular proliferation might be specifically inhibited.

Significance of pH on differentiation of human erythroid cell lines

As physiological factors and compounds, BSA and/or higher pH of the culture medium could induce the erythroid differentiation of cells. Optimum pH values of the culture medium for higher spontaneous differentiation of KU-812 and K562 cells after 7 days cultivation were 7.5 and 7.6, respectively. The synergistic effects on the differentiation were observed by exposure to hemin under the higher pH condition. In the presence of BSA, 25% of KU-812 and 40% of K562 cells became benzidine positive. Synergistic effects of BSA and the higher pH of the medium were also observed.

PH calibration curve at 1.5 Tesla

The significance of pH as an indicator of the intracellular environment is well established and 31P NMR spectroscopy provides a non-invasive means of measuring pH (Gadian et al., 1979). The derivation of a pH calibration curve to be used with a whole body system for in vivo studies of pH is described. Different standard reference samples are considered, both internal and external, and the advantages of using an internal reference are established. It is concluded that PCr is the most suitable reference sample for this study, because it may be used dissolved in the solutions and because of its very narrow peak. Bo inhomogeneity and local susceptibility effects are thus minimised, and the experimental arrangement more closely resembles the in vivo situation.

The significance of pH for the inhibiting effect of phosphate buffer on the corrosion processes

The influence of pH on the protective effect of phosphate buffer on the corrosion processes was studied by measuring the amounts of elements released from a dental amalgam. The analyses were conducted by means of atomic absorption spectrophotometry. The protective effect of phosphate buffer was reduced in solutions with low pH, and mercury could be detected in the solutions. Phosphate buffer maintained its aftereffect in the pH region 6.8-5.5. The flow rate of the solution did not influence the inhibiting effect of phosphate buffer.

Effect of decreasing acidity on the extractability of inorganic soil phosphorus

The extractability of P by the water and anion exchange resin methods and reactions of soil inorganic P were investigated with seven acid mineral soil samples incubated with KOH solutions of various concentrations. The results were compared with the analytical data obtained from three soil samples incubated in a prolonged liming experiment. The resin extraction method proved more effective than the water extraction method. The amounts of P desorbed by both methods seemed to increase exponentially as the pH in the soil suspensions rose. The factors involved were discussed. On the basis of fractionation analyses P reacting to changes in the pH and participating in desorption processes was supposed to originate from secondary NH4F and NaOH soluble reserves. In general, as the acidity decreased NH4F-P increased at the expense of NaOH-P. In heavily limed gyttja soil also H2SO4-P increased. This was possibly induced by the precipitation of mobilized P as a Ca compound. The significance of pH in the extractability of soil P seemed somewhat to lessen as the amount of secondary P increased. The results were in accordance with the conception that liming improves the availability of inorganic P to plants and reduces the need for P fertilization. However, increasing of the soil pH involves the risk that P is more easily desorbed to the recipient water by the eroded soil material carried into the watercourse. Therefore, intensive liming is not recommendable close to the shoreline. Further, it should be taken into account that liming of lakes may also result in eutrophication as desorption of sedimentary inorganic P is enhanced.

Significance of Ph -Negative Marrow Cells in Ph -Positive Chronic Granulocytic Leukemia

Fifty-six of 195 Ph1-positive patients with chronic granulocytic leukemia were found to have Ph1-negative metaphases in marrow aspirates on one or more occasions. In 22 cases, Ph1-negative cells were found prior to initiation of antileukemic therapy. Five patients were in the blastic stage of the disease when Ph1-negative mitoses were seen. The finding of Ph1-negative cells appeared to be related principally to short duration of CGL and to administration of antileukemic therapy (conventional agents and doses, in most cases). Ph1-negative cells were usually not found more than 2 yr after the diagnosis of leukemia, but in a few cases, they were seen as long as 5-10 yr after diagnosis. Only a minority of metaphases analyzed were Ph1-negative, except in the case of 6 patients who transiently had 50% or more Ph1-negative cells after antileukemic therapy. The presence of Ph1-negative cells in marrow was not associated with any survival advantage in this series.

The Significance of Ph1 Mosaicism: a Report of Six Cases of Chronic Granulocytic Leukaemia and Two Cases of Acute Myeloid Leukaemia

Six cases of chronic granulocytic leukaemia (CGL) and two cases of acute myeloid leukaemia (AML) with dual populations of karyotypically normal and Philadelphia (Ph1) chromosome-positive cells are described. GTG and QF-banding characterized the Ph1 as resulting from a 9/22 translocation in all eight cases. Four of the patients suffering from CGL presented with 100% Ph1-positive bone marrows, and after receiving intensive chemotherapy, karyotypically normal cells were demonstrated. The other two patients with CGL showed Ph1 mosaicism at presentation. The two patients with AML exhibited Ph1 mosaicism at presentation and throughout the course of the disease. In both of these patients, a marker No. 10 chromosome was found in some of the Ph1-positive cells and in one hyperdiploidy was observed to have developed only in the clone with the additional chromosome anomaly.

A NOTE ON THE USE OF MOSAIC GOLD

1 CORBETT, W. M., 'The Alkaline Degradation of Modified Cellulose,' The Journal of the Society of Dyers and Colourists, 76, No. 5 (1960), 265-271. 2 PADFIELD, TIM, 'The Deterioration of Cellulose, A Literature Review,' Problems of Conservation in Museums, ICOM, VnII, Editions Eyrolles Paris and George Allen and Unwin Ltd., London 1969, pp. 119-164. 3 Unpublished notes Seminar on the Scientific Approach to the Preservation of Paper Artifacts, October 1971. Institute of Paper Chemistry, Appleton, Wisconsin. 4 TALBOT, WILLIAM, The Action of Bleaching Agents on Artists Pigments, Jan. 26, 1962. Report Submitted to the Conservation Center of the Institute of Fine Arts, New York University. 5 Private Communication, DONALD KELMAN, Kyoto, Japan. 5 July 1973. 6 BARROW, W. J., 'Hot vs. Cold Extraction Methods for Making a pH Determination,' TAPPI, 46, No. 8, (1963), 468-472. 7 KING, A., PELIKAN, A., and FALCONER, W. E., 'The Use of the Archivist's Pen and Universal pH Solution for Estimating the Surface pH of Paper,' Studies in Conservation, 15 (1970), 63-64. 8 Unpublished results, FALCONER, W. E., KING, A., and PHELAN, W. 9 JOEL, A., INDICTOR, N., HANLAN, J. F., and BAER, N. S., 'The Measurement and Significance of pH in Paper Conservation,' Bull. IIC-AG, 12, No. 2 (1972), 119-125.

The Measurement and Significance of pH in Paper Conservation

The Measurement and Significance of pH in Paper Conservation

The Measurement and Significance of pH in Paper Conservation

AbstractThe conservator faced with the need to assess the acidity of a paper support cannot resort to the more rigorous cold extraction methods. The surface electrode permits the non-destructive measurement of pH. The resultant data, however, must be interpreted with caution since the nature of the paper support and any additive materials will have a profound effect on the measured pH.It is further noted that extreme care must attend the conditioning of the surface electrode prior to measurement. Conditioning is optimum when the electrode is immersed in a buffer of pH near that of a test reading, of the paper surface.

Recent experiments on crystal growth in gels

The paper gives an account of recent experiments on nucleation and crystal growth in gels and their relationship to crystal size and perfection, with special reference to calcium tartrate, lead iodide and silver iodide. Because the crystals in any one system grow competitively, nucleation is a key issue which, in all likelihood, governs the practical utility of the technique as a whole. Its limitation is believed to be the principal function of the gel. Heterogeneous nucleation is possible, but is substantially suppressed by the protective character of the medium. Moreover, there is evidence that a large number of the macroscopic crystals obtained owe their existence to “homogeneous” nuclei, rather than foreign substrates. The significance of pH and other factors which affect solubility has been explored and an attempt made to distinguish between the conditions which affect nucleation and those which affect growth. The conclusions are believed to have general validity, but for complete reliability each system must still be investigated in its own terms. The gel method is capable of yielding crystals of high optical perfection, of a variety of materials which have so far resisted orthodox growth techniques.

The significance of amino acids for the growth ofBordetella pertussis

Amino acid utilization by various strains ofBordetella pertussis, conditions for the preparation of casein hydrolysates, and the significance of pH for growth were studied. For achieving maximum growth the presence of casein hydrolysate amino acids in sufficient concentration is important since they determine total growth. The amino acids can be divided into two groups. The first group comprizes those which are at the same time sources of energy and whose utilization from the medium stops multiplication. Amino acids from the second group are utilized slowly and remain in the medium after growth cessation. The growth rate depends on the presence of all amino acids from the first group. They can be mutually substituted but the growth rate decreases.

Histochemical methods for calcium.

An account is given of an investigation of histochemical methods for calcium using standard test tissues (McGee-Russell, 1957) known to contain calcium salts, as test objects upon which to assess the success, reproducibility, and mutual consistency of methods. The methods for the revelation of calcium in the literature fall into two groups: metal substitution techniques, and dye-lake reactions. Published methods have been tested and many have been found of little use for cytological investigations. A set of six metal substitution techniques, including a new copper dithioxamide method, has been established as giving useful results. The empirical basis of the staining reactions for calcium with dyestuffs has been investigated, and sensitive and specific techniques using anthraquinone derivatives are outlined. The significance of pH in dye-lake reactions is emphasized, and it is pointed out that previous results with anthraquinone dyestuffs have been achieved by an empirical adjustment of pH in the staining solution. The necessity of making a distinction between the formation of a dye-lake precipitate as a true histochemical positive, and staining effects which may occur upon tissue components in the neighborhood of calcium deposits, through the interaction of the dye, the dye-lake, the calcium salt, and the matrix, is stressed. An oxazin dyestuff, gallamine blue, recently introduced for the staining of calcium deposits, was found to be inconsistent in its results, and capable of giving misleading information. Its general use is not recommended. The possibility of studying calcium deposits by means of the presence of contaminating metals is considered. The reagent sodium rhodizonate was found to give very fine localization of known calcium deposits in a number of tissues.

Correction - Significance of pH in Determination of Vanillin by Ultraviolet Absorption

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCorrection - Significance of pH in Determination of Vanillin by Ultraviolet AbsorptionDuane T. Englis and Louis A. WollermanCite this: Anal. Chem. 1957, 29, 12, 1893Publication Date (Print):December 1, 1957Publication History Published online18 July 2002Published inissue 1 December 1957https://doi.org/10.1021/ac60132a601RIGHTS & PERMISSIONSArticle Views36Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (150 KB) Get e-Alerts Get e-Alerts

Significance of pH in Determination of Vanillin by Ultraviolet Absorption

Significance of pH in Determination of Vanillin by Ultraviolet Absorption

The significance of pH, ion activities, and membrane potentials in colloidal systems.

The significance of pH, ion activities, and membrane potentials in colloidal systems.