Conventional Precipitation Method Research Articles

Detection, using a novel method, of a high prevalence of cryoglobulinemia in persistent hepatitis C virus infection

To elucidate precisely the prevalence and significance of cryoglobulinemia in hepatitis C, we examined the prevalence of serum cryoglobulin (CG) among 232 consecutive hepatitis C virus carriers (23 asymptomatic carriers, 164 with chronic hepatitis, 45 with cirrhosis), 30 consecutive hepatitis B virus carriers and 100 age- and sex-matched healthy volunteers. We used a gel-diffusion procedure that detects CG with greater sensitivity and specificity than the conventional precipitation method. Among the 232 patients, 166 were tested for the presence or absence of CG by the precipitation method also, which showed 60 (36.1%) patients to be positive for CG. On the other hand, 164 of the 232 patients (70.7%) were positive for CG using the diffusion method. 5 (16.7%) of the 30 HBV carriers and 2 (2%) of the healthy volunteers also were positive for CG using the gel-diffusion procedure. CG was detected more frequently among the patients with chronic hepatitis or cirrhosis than the asymptomatic carriers. In spite of the high prevalence of CG positivity, only one patient had symptoms related to cryoglobulinemia. Positivity for CG was not related to viral serogroup, viral load or the presence of antinuclear antibody, but it was related closely to CH50: 58 of 63 (92.1%) patients with lower levels of CH50 were positive for serum CG. In conclusion, cryoglobulinemia is a very common feature of chronic hepatitis C.

Magnetism of pure iron jarosites

Stoichiometrically pure jarosites of the formula $A{\mathrm{Fe}}_{3}(\mathrm{OH}{)}_{6}({\mathrm{SO}}_{4}{)}_{2}$ with $A={\mathrm{Na}}^{+},$ ${\mathrm{K}}^{+},$ ${\mathrm{Rb}}^{+},$ and ${\mathrm{NH}}_{4}^{+}$ have been afforded by a newly developed redox-based, hydrothermal method. The jarosites exhibit an intralayer antiferromagnetic exchange interaction $(\ensuremath{-}829\mathrm{K}l{\ensuremath{\Theta}}_{\mathrm{CW}}l\ensuremath{-}812\mathrm{K})$ and transition temperatures for long-range order (LRO) $(61\mathrm{K}l{T}_{N}l65\mathrm{K})$ that are essentially insensitive to the size of the ${A}^{+}$ ion. A cusp at ${T}_{N}$ in the ac susceptibility curve is frequency independent. The origin of LRO is consistent with coupling of jarosite layers exhibiting a net magnetization, which arises from an anisotropy developed, most likely, from the Dzyaloshinsky-Moriya (DM) interaction. A canted intralayer spin structure, which is a consequence of the DM interaction, is signified by a remanent magnetization $(\ensuremath{\sim}53\mathrm{K}l{T}_{D}l\ensuremath{\sim}58\mathrm{K}),$ the magnitude of which depends on crystallite size. X-ray single crystal analyses of the pure ${\mathrm{Fe}}^{3+}$ jarosite compounds reveal that the kagom\'e layers are structurally invariant with those of their ${\mathrm{Cr}}^{3+}$ and ${\mathrm{V}}^{3+}$ relatives. This structural homology allows the sign and magnitude of exchange coupling within kagom\'e layers to be correlated to the different orbital parentages engendered by the ${M}^{3+}$ d-electron count. Infrared studies show the presence of ${\mathrm{H}}_{2}\mathrm{O}$ within the kagom\'e layers of alkali metal and hydronium ion ${\mathrm{Fe}}^{3+}$ jarosites prepared by conventional precipitation methods; conversely, ${\mathrm{H}}_{2}\mathrm{O}$ is absent within the kagom\'e layers of jarosites prepared by the new redox-based hydrothermal methods. These results suggest that the absence of LRO in $({\mathrm{H}}_{3}\mathrm{O}){\mathrm{Fe}}_{3}(\mathrm{OH}{)}_{6}({\mathrm{SO}}_{4}{)}_{2}$ is due to structural and magnetic disorder arising from proton transfer from the interlayer hydronium ion to the bridging hydroxide ions of the kagom\'e layers.

Removal of Nickel from Electroless Nickel Plating Rinse Water with Di(2‐Ethylhexyl)phosphoric Acid‐Impregnated Supports

Electroless nickel plating technology is playing an increasingly important and indispensable role in many fields such as the electronic and automobile industries. As a result, the treatment of the rinse water containing about 50 mg/dm3 of nickel is becoming a serious environmental problem. Although this water is currently treated by the conventional precipitation method, a method without sludge generation is highly desired. This study explores the possibility of removing and recovering nickel from the rinse water with di(2‐ethylhexyl)phosphoric acid‐impregnated supports (D2EHPA‐IS). Macroporous polymer and oil adsorbents made of synthetic and natural fibers as the supporting materials were tested for the nickel removal abilities from simulated rinse water. In the batch experiments, more than 90% of the nickel can be adsorbed by these D2EHPA‐IS without pH adjustment. The adsorption of nickel reaches the equilibrium within 1.2 ks at 298K at a shaking rate of 140 rpm. The pH‐dependency of the nickel adsorption by the D2EHPA‐IS shows that the nickel is adsorbed by a cation exchange reaction. The adsorbed nickel can then be readily eluted with mineral acids. Most of the IS can be used many times without losing their adsorption abilities. In the column experiments, the breakthrough curves of nickel for these supports indicate that the nickel–D2EHPA complex formed at the high nickel loading region tends to dissolve into the aqueous phase. These findings lead to the conclusion that most of the studied D2EHPA‐IS are effective for the removal and recovery of nickel from an electroless nickel plating rinse water in batch mode.

Effect of the P/Al ratio of Al-P-O on the catalytic activity of o -methylation of catechol with methanol

Al-P-O catalysts with different P/Al ratios from 0 to 2.0 were synthesized by conventional precipitation method. The effect of P/Al ratio on the textural and surface properties, and the catalytic activity in the reaction of catechol with methanol were studied by XRD, IR, BET and TPD methods. At P/Al<1.0, the samples were mixtures of aluminium phosphate and amorphous alumina. With increasing P/Al ratio, crystalline AlPO4 and NH4AlP2O7 phases were formed and the surface area of the samples decreased. The catalytic activities for the O-methylation of catechol with methanol have a correlation with the acid amounts. Guaiacol was obtained as a major product and the highest guaiacol yield of ca. 45% was obtained from the sample with P/Al=1.

Platinum Recovery Using Calcium Vapor Treatment

To develop an effective process for the recovery of precious metals from scrap, a new platinum (Pt) extraction process using alloy formation by calcium (Ca) vapor and successive leaching with an aqueous solution were investigated. Pure Pt samples were reacted with Ca vapor at constant temperatures ranging between 1073 and 1173 K for three to twelve hours, and Ca–Pt alloy samples were synthesized. The obtained Ca–Pt alloy was then dissolved in aqua regia or in an aqueous HCl solution at room temperature. Platinum was recovered from the leaching solution by conventional (NH4)2PtCl6 precipitation method, and the amount of Pt obtained by each process was analyzed. It was found that more than 90% of the Pt was recovered by this process. After Ca vapor treatment, 100% of the Pt was dissolved when kept in aqua regia for one hour, whereas only 14% of untreated pure platinum was dissolved when kept in aqua regia for four hours. In some experiments, the obtained Ca–Pt alloy samples were oxidized in air for reducing the amount of acid needed for dissolution. Although Pt hardly dissolves in aqueous HCl solution at room temperature, it was found that Ca vapor treatment followed by oxidation is effective in increasing the rate of dissolution in aqueous HCl solution.

Calculation of coronary risk in Type II diabetes: another cause for concern

We read with interest the paper by Stevens et al. [1], in which they described a new equation for calculating coronary heart disease (CHD) risk in patients with Type II diabetes mellitus. The new equation, which is based on the U.K. Prospective Diabetes Study (UKPDS) [2], utilizes HbA c as a continuous variable unlike the Framingham Figure 1 Comparison of the direct HDL cholesterol measurement method, marketed by Roche (Y) with the conventional precipitation method (X) using the method of Passing and Bablock for linear regression analysis The dashed lines indicate the 95% confidence limit. Similar results were obtained for methods marketed by the companies Sigma, Wako and Randox. (a) Patients with Type I diabetes, and (b) patients with Type II diabetes. risk equations [3], which are only interested in the presence or absence of diabetes. The inclusion of HbA c as a continuous risk factor for CHD in Type II diabetes resulted in a significant increase in the 10-year risk. The National Service Framework for CHD prevention proposed that statins should be limited to patients with a

溶媒抽出法による使用済み無電解ニッケルめっき浴からの金属成分の分離

With increasing importance of the electroless nickel plating technology in many fields such as electronic and automobile industries, the treatment of the spent baths is becoming a serious problem. Although the spent baths are currently treated by the conventional precipitation method, a method without sludge generation is desired. This work aims at establishing a recycling process of nickel from the spent baths. Solvent extraction of nickel, iron, and zinc in two types of spent baths (A and B) has been investigated using 2-hydroxy-5-nonylacetophenone oxime (LIX84I) and the acidic organophosphorus compounds such as bis (2-ethylhexyl)phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) and bis (2, 4, 4-trimethylpentyl) phosphinic acid (Cyanex272) as the extractants. Spent bath A is weakly acidic (pH 4.8) and contains 70 g m-3 of zinc as an impurity, and spent bath B is very weakly acidic (pH 6.0) and contains boron. The following results have been obtained: (i) Nickel in spent bath A can be extracted with LIX84I at the pH larger than 6 with high efficiency leaving most of zinc and iron in the aqueous phase. Also, nickel in spent bath B can be efficiently extracted without adjusting pH. (ii) According to the McCabe-Thiele analysis, the concentrated nickel sulfate solution (> 100 kg-Ni m-3) with low sulfuric acid content is obtained by the countercurrent two stage stripping from the Ni-bearing LIX84I using the mixed solution of 0.9 kmol m-3 NiSO4 and 1 kmol m-3 H2SO4 as the stripping reagent. (iii) Iron and zinc in spent bath A can be selectively extracted with the acidic organophosphorus compounds. PC88A and Cyanex272 are more advantageous than D2EHPA because, in the former extractants, the coextraction of nickel is lower and the stripping of iron and zinc is easier. Based on these results, the flowsheets for recovering nickel from the spent baths are proposed.

Preparation of high surface area tin oxide powders by a homogeneous precipitation method

Tin oxide powders were synthesized by a homogeneous precipitation method using urea from SnCl 4 solution. This method resulted in the formation of nanoscale precursor powders in the range of 3 to 4 nm in diameter together with a narrow particle size distribution, while the conventional precipitation method led to the formation of precursor powder of not only larger particles (4–6 nm) but also wider particle size distribution. When these precursor powders were calcined at 600°C for 2 h, the powders from the homogeneous precipitation method showed higher specific surface areas (24–44 m 2/g). On the other hand, the powders from the precipitation method exhibited lower specific surface areas (15–18 m 2/g).

Synthesis of high surface area tin oxide powders via water-in-oil microemulsions

Nanoparticles of tin oxide have been synthesized from water-in-oil microemulsions consisting of water, AOT (surfactant), and n-heptane (oil). The aqueous cores of microemulsions were used as constrained microreactors for the precipitation of precursor hydroxide particles. When these precursor powders were calcined at 600°C for 2 h, they exhibited a higher Brunauer–Emmet–Teller (BET) surface area of 86 m 2/g. On the other hand, the powders obtained from the conventional precipitation method showed a lower surface area of 19 m 2/g.

Characteristics of methane combustion over La-Cr-O catalysts

The catalytic activities of methane combustion of La–Cr–O catalysts prepared with and without polyacrylic acid as a template have been compared. The polymer-templated catalyst had a higher BET surface area, 12.3 m2 g−1, than that obtained from the conventional precipitation method, 2.9 m2 g−1. The results of XRD and SEM experiments suggested that the structural characteristics were almost similar. Surprisingly, the areal rate of methane combustion over the catalyst with a small surface area was ten times larger than that of the catalyst with a large surface area. However, the site time yields (STY) based on the oxygen adsorption capacity were similar, independent of the surface area and preparation conditions.

Emulsion precipitation of submicron zinc oxide powder

Ultrafine zinc oxide powder was successfully synthesized through the emulsion precipitation process. The aqueous solution containing zinc cations was well emulsified in n-heptane solution, and then precipitated by adding ammonia. After calcination of the precipitates, submicron zinc oxide powder with a near spherical morphology was obtained. On comparison with the conventional precipitation method, this developed process was confirmed to be superior in preparing uniform ZnO powder and reducing its particle size. The emulsion stability was significantly affected by the ratio of the volume of the oil phase to that of the aqueous phase, and this ratio also influenced the mean particle size of ZnO powder.

Selective Oxidation of Toluene over the Ultrafine Composite Molybdenum-Cerium Oxide Particles

Abstract The ultrafine composite Mo-Ce oxide particles exhibit higher catalytic activity for selective oxidation of toluene to benzaldehyde than the corresponding large oxide particles prepared by conventional precipitation method, which can be correlated to the higher reactivity of lattice oxygen ions in the ultrafine oxide particles.

A novel method for the synthesis of perovskite-type mixed metal oxides by the inverse microemulsion technique

Nanoparticles of lanthanum-nickel, lanthanum-copper and barium-lead oxalates with the metal molar ratios of 1∶1, 2∶1 and 1∶1, respectively, have been successfully synthesized in inverse microemulsions. These metal oxalate particles of about 20 nm diameter were readily calcined into single-phase perovskite-type LaNiO3, La2CuO4 and BaPbO3. The calcination temperatures for these metal oxalates were generally 100–250°C lower than those for the metal oxalates prepared by the conventional aqueous solution precipitation method. The substantial reduction in the calcination temperatures is attributed to the formation of uniform, near-spherical nanoparticles of the metal oxalate precursors obtained by the unique inverse microemulsion technique.

Synthesis of ultrafine hydroxyapatite particles by a spray dry method

A technique was developed to synthesize hydroxyapatite (HA) with a nanocrystalline structure. The method involved the initial preparation of an aqueous solution using inorganic water-soluble compounds. A precursor powder mixture was subsequently formed via atomization by spray drying the aqueous solution. Calcination of the spray-dried precursor powder resulted in the formation of a nanocrystalline structure. Structural and morphological characterizations of the synthesized material were conducted using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and electron microscopy (SEM and TEM). Particle size distribution was analyzed using X-ray peak broadening and TEM techniques. The thermal stability of the powder was also characterized and was compared with that of powders made using conventional precipitation methods.

Acid-leaching of sodium brannerite: synthesis and structure of Na 0.13(V 0.13Mo 0.87)O 3 · nH 2O

In dilute hydrochloric acid NaVMoO 6, which has a layered “brannerite” structure, participates in an acid-leaching reaction that results in the formation of a metastable compound with the stoichiometry Na 0.13(V 0.13Mo 0.87)O 3 · nH 2O and the structure of “hexagonal” MoO 3. The locations of the sodium ions and water molecules in the channels of this structure, space group P6 3 with a = 10.628(1) Å and c = 3.6975(7) Å, were determined through Rietveld refinement of powder neutron diffraction data collected on deuterated samples. The water molcules are important in providing a stable environment for the sodium ions, which are octahedrally coordinated by four framework oxygen atoms and two water molecules. In an attempt to understand the mechanistic aspects of the acid-leaching reaction, samples of the hexagonal phase were formed with a range of V : Mo contents from aqueous NaVMo solutions via conventional precipitation methods. Although phases could be stabilized with the same crystallography as the brannerite-derived products, the solution precipitates contained vacancies in the transition metal framework and a higher concentration of sodium in the channels. These compositional differences led to a significant reduction in the apparent high-temperature stability of the solution-derived phases compared to that of their brannerite-derived counterparts. There is some evidence to suggest that the structural filiation between brannerite and hexagonal MoO 3 may be responsible for the unique stoichiometry and stability of the products of the acid-leaching reactions and that the acid-leaching reactions do not proceed through a simple dissolution/precipitation mechanism.

Copper/zirconia catalysts for the synthesis of methanol from carbon dioxide: Influence of preparation variables on structural and catalytic properties of catalysts

The effect of the preparation method on the catalytic behaviour of copper/zirconia catalysts for the synthesis of methanol from carbon dioxide has been investigated. Conventional precipitation, ion exchange and impregnation methods have been used in addition to the methods of deposition precipitation and co-precipitation in the presence of reducing agents. Precipitation reactions at constant pH were found to be an interesting route for the preparation of highly active and selective Cu/ZrO 2 catalysts. Efficient catalysts were found to consist of microcrystalline copper particles which are stabilised through interaction with an amorphous zirconia matrix, resulting in a high interfacial area. The determination of the copper surface area by nitrous oxide titration revealed that the methanol synthesis activity did not exhibit a general correlation with the specific copper surface area of the catalysts; such a correlation is found only within families of similarly prepared catalysts. The influence of the residence time on the relative selectivity γ (CH 3OH/CO ) was investigated in the temperature range 473 to 533 K at a pressure of 1.7 MPa. The results indicated that methanol and desorbing carbon monoxide are probably formed from carbon dioxide via parallel reaction pathways. The activation energies calculated from these results were E A = 47.9±1.4 kJ mol −1 for the methanol synthesis reaction and E A = 93.2±2.9 kJ mol −1 for carbon monoxide formation.

Glutathione may inhibit sodium-dependent phosphate transport by renal brush-border membrane vesicles.

Glutathione, a biological reductant, can affect certain aspects of transport function in renal cortical slices. The influence of glutathione on the rate of sodium-dependent phosphate uptake into renal brush-border membrane (BBM) vesicles was examined. Vesicles were obtained from rat renal cortex by the conventional calcium precipitation method. The amounts of GSH and oxi-glutathione were measured by chromatography. The vesicles were incubated for 15 min with glutathione (10 mM) prior to a 1-min influx of phosphate. The incubation with glutathione reduced the phosphate uptake from 1887 +/- 217 to 1496 +/- 116 pmol/mg (n = 5, p less than 0.05). A kinetic study revealed that the incubation with glutathione resulted in an increase of Km in the sodium-dependent phosphate transporter from 85 +/- 7.9 to 159 +/- 18 microM (n = 5, p less than 0.05). Glutathione was catabolized rapidly by the incubation with BBM, and a concomitant production of oxi-glutathione was recognized. Incubation with oxi-glutathione (10 mM) for 15 min, however, did not affect the phosphate uptake, the present results suggest that incubation with reduced-form glutathione decreases the affinity of the sodium-dependent phosphate transport across the renal brush-border membrane, and that catabolism of glutathione may be linked the inhibitory mechanism.

水中の病原性細菌の定性的検出法

An improved method was developed from the conventional precipitation method for isolation of pathogenic bacteria from water.Various kinds of bacteria grown in culture media were suspended in sterilized water. Ferric chloride and diatomaceous earth were added to the resulting suspension to a final concentration of 0.02 % and 0.1 %, respectively. The suspensions were adjusted to be neutral or slightly alkaline with 1 N sodium hydroxide solution. They were allowed to make precipitates for 90 minutes. Then the supernatants were removed. It was demonstrated that the precipitates held a majority of the bacteria. Furthermore, the bacteria could be recovered from the precipitate even if only a few bacteria (less than 100 cfu/liter) were suspended in the original water. This method is applicable to various kinds of water, such as drinking water, surface water, and drainage, if an adequate amount of diatomaceous earth is added to the water.

An improved method for purifying α-metallophthalocyanines for use as radionuclide preparation targets

Modifications of the conventional precipitation method for purifying α-metallophthalocyanines give a product essentially free of the usual occluded impurities, significantly decreasing the total metallic content of extracted radionuclides. Application of the improved method to the preparation of an α-CoPc target is described.

Polydiallylorthophthalate resist for electron‐beam lithography

AbstractPolydiallylorthophthalate, PDOP, of low molecular weight and low molecular weight dispersivity has been prepared and investigated as a negative resist for electron‐beam, X‐ray and ultraviolet lithographies. The resist polymers were prepared by a conventional fractional precipitation method. It has been found that a high resolution pattern is obtained by using a molecular weight of 1 × 104 and an Mw/Mn &lt; 2. This gives a good solubility difference between the exposed and unexposed portions in the developer. Resolution is less than 1 μm without any scum. Sensitivity for 15 kV electron bourns is 4 × 106C/cm2; and for X‐rays (Al Kα) it is 100 mJ/cm2. Sensitivity for UV is 10 times that of poly(methyl methacrylate), and resistance for C3F8 dry etching is comparable to AZ‐1350J.