Zirconyl Phosphate Research Articles

The Effect of Nanosized Layered Materials on the Structure-Property Relationship of Poly(aniline)s: An FTIR Kinetic Study

Aniline (ANI) was chemically polymerized in the presence of two different nanosized layered materials, zirconylphosphate (ZP) and molyptic acid (MA) under different experimental conditions with nitrogen purging at 45°C. The effect of nanosized layered materials on the rate of polymerization (Rp) and Fourier transform infra red-relative intensities (FTIR-RI) of benzenoid and quinonoid forms of poly(aniline) (PANI) were tested. The thermal stability and electrical conductivity values were boosted with the help of nanosized materials. High resolution transmission electron microscope (HRTEM) determined the size of nano material and its uniform distribution on the PANI matrix. For the sake of comparison, o-toluidine (OT) was polymerized under the same experimental conditions and its structure-property relationship in the presence of nano materials were also tested and critically compared with PANI systems.

Description and characterization of an electrochemical hydrogen compressor/concentrator based on solid polymer electrolyte technology

Proton-exchange membrane (PEM) technology is commonly used for manufacturing water electrolysers, H2/O2 fuel cells and unitized regenerative fuel cells. It can also be used to develop electrochemical compressors, for the purpose of concentrating and/or pressurizing gaseous hydrogen. The aim of the work reported here was to evaluate the main operating characteristics of a laboratory scale (≈10 N liter/h) monocell compressor. The role of various operating parameters (current density, temperature of electrochemical cell, water vapor partial pressure in the hydrogen feed gas, anodic gas composition, etc.) has been evaluated and is discussed. It is shown that the relative humidity of hydrogen oxidized at the anode of the compressor should be adapted to the current density during operation to avoid mass transfer limitations or electrode flooding. A cell voltage of 140 mV is required at 0.2 A cm−2 to compress hydrogen in one step from atmospheric pressure up to 48 bar, corresponding to an energy consumption of ca. 0.3 kW h/Nm3. Experiments have been performed up to 130 bar. Series connection of several compressors is recommended to reach output pressures higher than 50 bar. To reduce gas cross-permeation effects which can negatively impact the efficiency of the compressor, additional experiments have been made using Nafion membrane modified by addition of zirconyl phosphate. Finally, data related to the extraction of hydrogen from H2–N2 gas mixtures are also reported and discussed.

Low-Thermal Expansion Zirconyl Phosphate Ceramic

Low-Thermal Expansion Zirconyl Phosphate Ceramic

Study on the preparation of a137Cs/137mBa radionuclide generator

137mBa has been applied successfully to dynamic studies for diagnosis in nuclear medicine for a long time. A variety of inorganic exchangers have been employed for the separation of137mBa from its parent137Cs. In the present study, cupric cobaltic ferrocyanide and amorphous zirconyl phosphate were synthesized and compared for use in a137Cs/137mBa generator. The results show that the former can adsorb137Cs more efficiently and provide high elution yield of137mBa with greater than 99.99% radionuclide purity. A new generator involving multimillicuries of137mBa, in connection with a computerized detection system, has been constructed.

Thermal and dielectric properties of zirconyl phosphate compact

Experimental results are presented on the measurements of thermal expansion (up to 1500°C), thermal conductivity (up to 1000°C), dielectric constant (up to 450 °C) and tanδ (up to 800 °C) of zirconyl phosphate compacts obtained by sintering at 1600°C. The thermal expansion coefficient of the samples at the temperature below 1100°C was less than 1.7 × 10−6°C−1. The samples showed a definite shrinkage at temperatures of 1110 and 1470°C due to the phase transformations. The expansion at 1500°C was less than that at 1100°C probably because of the phase transformation. The thermal conductivity at room temperature was a very small value (0.0046 to 0.0065 cal s−1 cm°C−1 cm−2). The dielectric constant was close to 9. The value of tan° (−0.0001) measured is one of the lowest values for ceramic materials.

ChemInform Abstract: LOW‐THERMAL‐EXPANSION POLYCRYSTALLINE ZIRCONYL PHOSPHATE CERAMIC

AbstractDie Synthese von Wärmeschock‐beständigem Material aus 2 ZrO2‐ P2O5 wird untersucht.

Low‐Thermal‐Expansion Polycrystalline Zirconyl Phosphate Ceramic

The synthesis of thermal‐shock‐resistant material from zirconyl phosphate, 2ZrO2P2O5, was investigated. Modifications of the compound were examined; only the a phase appears to be thermodynamically stable. Sintering of a‐phase powder to a dense ceramic was promoted by adding a metal oxide. Crystalline zirconyl phosphate has a low average thermal expansion coefficient. The relation of microcracking to grain size and strength was studied using specimens sintered under varied conditions. A strong low‐thermal‐expansion polycrystalline ceramic was obtained by controlling grain growth.

A Method To Measure Carcinoembryonic Antigen Neosynthesis by Cultured Colon Carcinoma Cells<xref ref-type="fn" rid="fn2">2</xref>

A double-antibody radioimmunoprecipitation assay was used to measure the rate of incorporation of radioactive precursors into carcinoembryonic antigen (CEA) newly synthesized by cultured human colon carcinoma (LoVo) cells. Mixtures of 125I-labeled CEA and standard CEA were used to construct titration curves as a function of concentration, time of incubation, and temperature for goat anti-CEA serum and rabbit antigoat serum. In contrast to the zirconyl phosphate gel method, the double-antibody technique did not precipitate compounds with low molecular weights. Similar slopes were observed when standard CEA was used to inhibit immunoprecipitation of 125I-labeled CEA by both the zirconyl phosphate gel and the double-antibody techniques. When CEA produced by the colon carcinoma cells (CEA-LoVo) was used to inhibit immunoprecipitation of radioactive 125 I-labeled CEA, the curve was superimposed upon that elicited for standard CEA. CEA-LoVo incorporated significant amounts of [N-acetyl-3H]glucosamine, and chromatography of the 3H-labeled CEA-LoVo eluted with a peak superimposed upon that of the First British Standard for CEA. This method was subsequently used to estimate changes in the rate of CEA neosynthesis by LoVo cells as a function of culture age. The rate of incorporation of [N-acetyl-3H]glucosamine into CEA of LoVo cells in stationary phase was about three times that measured for cells in exponential growth. The technique described in this report has the advantage that labeling of CEA results from actual metabolic cellular activity. Therefore, it provides a tracer method to study the localization and kinetics of CEA synthesis by cultured colon cells.

20] Use of zirconyl phosphate gel for the separation of antigens from antigen—antibody complexes in radioimmunoassays: Assays for carcinoembryonic antigen, α-fetoprotein, and insulin

This chapter discusses the use of zirconyl phosphate gel (Z-gel) for the separation of antigens from antigen–antibody complexes in radioimmunoassay. Z-gel is a convenient and inexpensive reagent for the separation of free antigen from antigen-antibody complexes in certain radioimmunoassays. Z-gel can be used theoretically to separate a variety of antigens from their antibody complexes provided certain conditions can be satisfied— that is, if a pH can be found, at which the antigen and its antibody complex carry opposite net charge. Z-gel is a negatively charged gel at pH 6.25; it binds positively charged molecules, for example, proteins at a pH below their isoelectric pH. In the three radioimmunoassays described in this chapter, Z-gel at a pH of 6.25 is used to adsorb the positively charged antibody molecules (p I > 7), with their associated antigens, while leaving the negatively charged free antigens (CEA, AFP, and insulin) in solution. It has been shown that NH4 + is the preferred cation as Na + and K + decrease the ability of Z-gel to adsorb antigen–antibody complexes. In the chapter, are also described examples of radioimmunoassays, in which Z-gel has been used successfully, such as assays for carcinoembryonic antigen (CEA), α-fetoprotein (AFP), and insulin.

Extraction of human plasma or sera by heat treatment for a solid-phase radioimmunoassay of carcinoembryonic antigen.

Heat treatment and a solid-phase radioimmunoassay are combined to give a relatively simple and rapid procedure for assay of carcinoembryonic antigen in plasma or serum. The new way we describe to extract this antigen is an alternative to the conventional method of extraction with perchloric acid. Heating plasma or serum samples in acetate buffer (0.16 mol/L, pH 5.0) at 70 degrees C for 15 min precipitates out most of the heat-labile, nonspecific plasma proteins, but leaves most of the antigen in solution, with its immunochemical properties apparently unaffected. Comparison between the heat treatment and the perchloric acid extraction yielded comparable values when tested either by solid-phase radioimmunoassay or by the zirconyl phosphate precipitation method. An added advantage of our method is that it gives the same assay values for both plasma and serum. Results for a group of pathological plasma samples, assayed by both our method and the perchloric acid-zirconyl phosphate precipitation method, gave a correlation coefficient of 0.90.

The analytical reliability of the zirconyl phosphate method of plasma carcinoembryonic antigen.

We evaluated the analytical reliability of the carcinoembryonic antigen (CEA) method of Hansen. Our experience is based on performing over 23,000 CEA assays in more than 10,000 clinical samples. The sensitivity of the assay is 0.5 ng/ml. The precision must be defined as a function of concentration. In the range 2.6 to 12 ng/ml the coefficient of variation is 4.96 to 7.39%. Long-range studies of the reproducibility of the standard curve, over a period of several years and including 435 standard curves, have shown an overall mean B/Bo of 31.45% which is close to the theoretical optimal of 33%. The long-term 90 and 50% intercepts are 0.55 +/- 0.15 and 7.11 +/- 1.0, respectively. Interlaboratory surveys show good agreement between the means of the survey group and the target values but rather large individual discrepancies. The CEA method studied here is sensitive and reproducible in intralaboratory studies but less so in interlaboratory comparisons. The reagents have performed uniformly and close to specifications over an extended period of time.

The disparity of indirect and direct zirconylgel assays for carcinoembryonic antigen

Experience with the zirconyl phosphate gel (Z-gel) radioimmunoassays for plasma CEA levels below 20 ng/ml (the indirect method) and for levels greater than 20 ng/ml (the direct method) has shown that a disparity of values exists, caused by shifting from one assay to the other. This disparity is at least partially due to PCA-labile proteins reacting in the direct assay. It may be constant for individual patients but varies among patients. The magnitude of this disparity is independent of the CEA level (above 15 ng/ml).

A technical improvement in the radioimmunoassay of cyclic-AMP

An improvement in the technique for the radioimmunoassay of cyclic-AMP, wherein ammonium sulfate precipitation is replaced with zirconyl phosphate gel, is presented. This substitution produces a more stable pellet than that obtained with ammonium sulfate. This greatly reduces a potential source of error due to pellet instability.

Relationship of Carcinoembryonic Antigen to Blood Substances a and i: Evidence That the Antigenic Sites Are on Different Molecules

Abstract Extracts of human colon carcinomas have been assayed for the presence of blood group substance A and i activities using an automated quantitative hemagglutination-inhibition system. Carcinoembryonic antigen (CEA) activity was simultaneously assayed by the zirconyl phosphate gel radioimmunoassay. Isoelectric focusing of a perchloric acid tumor extract containing all three antigen activities indicated a similar pK1 for the three antigens. However, A- or i-specific affinity gel adsorption experiments showed that only the corresponding blood group antigen activity was removed from tumor extracts. CEA activity remained essentially the same after adsorption by these gels. Significant blood group activity could not be demonstrated in preparations of highly purified CEA or in CEA from which N-acetylneuraminic acid and fucose had been removed. Conversely, CEA activity was absent from preparations of purified blood group antigens and could not be unmasked by removal of the immunodominant β-galactose of the i antigen with β-galactosidase. These data provide evidence that the antigenic sites for CEA and blood group A and i antigens are located on different molecules in colon carcinoma extracts.

Radioimmunoassay methods for carcinoembryonic antigen

A comparison of three radioimmunoassay methods for measuring the concentration of carcinoembryonic antigen in plasma is presented. Experimental details are outlined for a slight modification of the zirconyl phosphate gel assay and for a coated tube sandwich assay and a rabbit anti-CEA: guinea-pig anti-rabbit double antibody system. The resulting assay profiles are discussed with reference to their potential in clinical practice.

Proceedings: Carcinoembryonic antigen. Report of a screening study.

Originally described as a specific marker for colonic carcinomas, carcinoembryonic antigen (CEA) has recently been demonstrated in elevated titers in patients with a variety of non-neoplastic diseases, especially in patients with serious metabolic disorders and in patients with inflammatory bowel disease. We are reporting results of CEA screening in 576 patients undergoing barium enema examination. None were known to have cancer, previously diagnosed or recurrent. Of this group, 23 were discovered to have primary or recurrent colonic cancers. CEA-radioimmunoassays by the Zirconyl phosphate gel method of Hansen were positive (>2.5 ng/cc) in 18 and greater than 5 ng cc in 15. However, in 4 of 13 early stage colonic carcinomas, CEA values were normal. Of the remaining 553 patients, none had proven cancer. Ninety-eight (18%) of them had elevated CEA values, but only 18 of these were greater than 5 ng/cc. Forty-six of these CEA positive patients had acute inflammatory bowel disease, acute gastrointestinal disorders, collagen diseases, or serious chronic metabolic diseases. Repeat CEA sampling in a third of the “false” positive group produced normal results in most. To date only 1 of the 98 “false” positive group is known to have developed a diagnosable cancer within the year. Of the CEA negative group, none have reported development of cancer. Caution is advised against interpreting a single elevated CEA value as synonymous with colonic cancer, and against dismissing the possibility of early colonic cancer in the face of a normal CEA value.

A radioimmunoassay for plasma insulin using zirconyl phosphate gel

A procedure for the detection of immunoreactive insulin in human plasma is described. The procedure is a rapid radioimmunoassay (3 hr) which uses zirconyl phosphate gel (Z-gel) at a pH of 6.25 to adsorb antibody-bound insulin while leaving free insulin in solution. Thirty-two samples of human plasma which had been assayed for immunoreactive insulin using a commercially available assay (Pharmacia Fine Chemicals, Piscataway, NJ) were also assayed on a blind basis for immunoreactive insulin using the Z-gel technique. A statistical comparison of the data obtained by the two methods yielded a highly significant ( P < 0.01) coefficient of correlation (0.998). A known amount of bovine insulin was added to each of these plasma samples, and the Z-gel assay repeated. The mean percentage recovery of added insulin was 100.4 ± 17.0 (SD). In addition, the insulin response of two healthy individuals to the ingestion of 100 g of glucose was determined using the Z-gel assay. The insulin response curves were similar to those described by other investigators.

Circulating carcinoembryonic antigen (CEA): relationship to clinical status of patients with inflammatory bowel disease.

Plasma levels of circulating carcinoembryonic antigen (CEA) were measured by zirconyl phosphate gel radioimmunoassay in 112 patients with chronic inflammatory bowel disease. The levels were then related to category, extent, duration, and severity of disease, as well as to the ages and surgical status of the patients. The distribution of CEA levels and their mean values were significantly raised over the levels in 33 normal control subjects, and were similar among patients with ulcerative colitis compared with those with granulomatous bowel disease. Positive values were defined as those in excess of 2.5 ng/ml. Positive assays occurred in 42% of ulcerative colitis patients, in 38% of Crohn's disease patients, and in 40% of the total group with inflammatory bowel disease. Among normal control subjects, only 3% were positive. Among inflammatory bowel disease patients, positive CEA assays occurred more frequently with more severe disease, more extensive anatomical involvement, younger ages, and shorter duration of disease. Those patients who had undergone total colectomy showed levels of circulating CEA and frequency of CEA positivity similar to those of an age-matched normal control group. Levels of CEA did not correspond with known cancer risk factors in patients with inflammatory bowel disease. Although rising or persisting plasma CEA values unrelated to severity and extent of disease may indicate an unfavourable prognosis in cancer, this study shows that a single CEA value in patients with chronic inflammatory bowel disease is not a reliable indicator of cancer risk.

Levels of transcobalamin II in normal human serum measured with zirconyl phosphate gel.

Zirconyl phosphate gel at pH 6.25 binds selectively to transcobalamin II and not to transcobalamin I. Using this technique, levels of TC‐II in 100 normal donors were determined to be 0.96 ± 0.2 ng of B12 bound per ml of serum. The stability of TC‐II at various temperatures, the lack of any difference between levels of TC‐II in males and females, and the lack of fluctuation of levels of TC‐II in any one individual's serum are shown.

Evaluation of a New Radioimmunoassay Method for Carcinoembryonic Antigen in Plasma, with Use of Zirconyl Phosphate Gel

Abstract A radioimmunoassay of carcinoembryonic antigen in plasma is described and evaluated. The assay can be easily performed and implemented in a clinical laboratory. Assessed by Rodbard’s statistical quality-control procedure, the assay is shown to be highly sensitive, precise, and reproducible.