Elucidation of a preparation method for copper ion-exchanged ZSM-5 samples exhibiting extremely efficient N2-adsorption at room temperature: effect of counter ions in the exchange solution

The adsorption of N₂ on a copper ion-exchanged ZSM-5 sample (CuZSM-5) prepared by ion exchange using an aqueous solution of copper propionate, Cu(C₂H₅COO)₂, was examined at room temperature by measuring the FT-IR spectra, adsorption isotherms and heat of adsorption. This sample was found to be extremely efficient in terms of N₂ adsorption with regard to both the amount and the energy (i.e., heat) of adsorption, compared with samples prepared by a conventional ion-exchange method using an aqueous solution involving Cu²⁺ and simple counter ions, Cl⁻ or NO₃⁻. To clarify the specificity of the newly-prepared sample, the ion-exchange of ZSM-5 with Cu²⁺ was carried out by employing aqueous solutions involving Cu²⁺ and various types of counter ions [propionate (C₂H₅COO⁻), acetate (CH₃COO⁻), formate (HCOO⁻), chloride (Cl⁻) and nitrate (NO₃⁻) ions]. When the ion exchange was performed by using a Cu(C₂H₅COO)₂ or Cu(CH₃COO)₂ solution, the Cu²⁺ species with propionate or acetate ligand (in the monomer state) were ion-exchanged in ZSM-5, as confirmed by the DR, EPR and FT-IR spectra for CuZSM-5. In contrast, Cu²⁺ species were present in the form of aquo-complexes in samples prepared with other solutions. This distinct difference can be ascribed to the difference in the pK_a values of the counter ions; carboxylate ions, with a high pK_a value, are inclined to form a complex with Cu²⁺. Using this newly applied Cu(C₂H₅COO)₂ solution, the present ion-exchange method has the potential to develop new effective materials that possess the specific adsorption and catalytic properties of CuZSM-5.     

Production of MAG of CLA in a solvent-free system at low temperature with <Emphasis Type="Italic">Candida rugosa</Emphasis> lipase

We attempted to produce MAG of CLA through lipase-catalyzed esterification of a FFA mixture containing CLA (referred to as FFA-CLA) with glycerol. Screening of lipases showed that MAG-CLA was produced efficiently at 5°C with Penicillium camembertii, Rhizopus oryzae, and Candida rugosa lipases. Among them, C. rugosa lipase was selected because the lipase is widely used as a catalyst for oils and fats processing. The reaction was conducted with agitation of a 300-g mixture of FFA-CLA/glycerol (1∶5, mol/mol), a 200-U/g mixture of C. rugosa lipase, and 2% water. When the reaction was conducted at 30°C, the esterification scarcely proceeded, owing to inhibition of the reaction by glycerol. But the reaction at 5°C eliminated the inhibition and produced MAG efficiently: The degree of esterification reached 93.8% after 58 h, and MAG content in the reaction mixture was 88.4 wt%. To reduce the reaction time, the reactor was connected with a vacuum pump after 24 h, and the reaction was continued with dehydration at 5 mm Hg. The degree of esterification reached 94.7% after 24 h of dehydration (48 h in total), and MAG content increased to 93.0 wt%. Candida rugosa lipase acted a little more strongly on cis-9, trans-11 CLA than on trans-10,cis-12 CLA, but the contents of the two isomers in MAG obtained from a 48-h reaction were the same as the contents in FFA-CLA.     

Renal Cyclooxygenase Products are Higher and Lipoxygenase Products are Lower in Early Disease in the pcy Mouse Model of Adolescent Nephronophthisis

Nephronophthisis (NPHP) is a pediatric form of hereditary polycystic kidney disease (PKD), and is the leading cause of end stage renal disease in children. The pcy mouse is an orthologous model of human NPHP, with a mutation in the Nphp3 gene. Renal phospholipase A₂, cyclooxygenase (COX) 1 and cyclic AMP are elevated in this model, suggesting that eicosanoid formation may be altered. In another type of PKD observed in the Han:SPRD-Cy rat, inhibition of eicosanoid production slows disease progression. If renal eicosanoids are similarly altered in NPHP, potential for pharmacologic intervention also may exist for this disorder. Therefore, renal fatty acids and eicosanoids were determined in pcy and normal mice at 15, 30 and 60 days of age by gas chromatography and HPLC–tandem mass spectrometry, respectively. Renal cysts in enlarged kidneys were observed in pcy mice by 15 days of age and increased over time. Renal phospholipid ARA levels were higher in pcy compared to normal mice at 15 and 30 days. Eicosanoid differences were observed starting at 30 days, when the COX products 6-keto-prostaglandin (PG) F_1α, thromboxane B₂ and PGE₂ were higher in pcy compared to normal kidneys. Overall, total COX products were elevated at 30 and 60 days. In contrast, the levels of the lipoxygenase (LOX) products were not altered until 60 days of age and these were lower in pcy kidneys compared to normal. These findings suggest that altered eicosanoids play a role in NPHP, and that manipulating these levels with pharmacologic agents may have therapeutic potential.     

Tuberculin sensitivity to purified protein derivatives from Mycobacterium other than tuberculosis (PPD-B, PPD-Y, PPD-F and PPD-C) and PPDs among patients with mycobacteriosis--cooperative study of the Research Committee for the Mycobacteriosis in Japan

Purified protein derivatives (PPDs) prepared from M. intracellulare (PPD-B), M. kansasii (PPD-Y), M. fortuitum (PPD-F), M. chelonei subsp. abscessus (PPD-C) and M. tuberculosis (PPDs) were simultaneously used in skin tests on patients diagnosed as having tuberculosis or atypical mycobacteriosis to reveal their specificity, clinical usefulness and immunological status of the patients. The mean diameter of reaction (redness) for patients with M. tuberculosis positive sputum (TB group, n = 71; age, 20-90 yrs) was PPDs, 20.4 mm; PPD-B, 7.9 mm; PPD-Y, 11.7 mm; PPD-F, 0.8 mm; and PPD-C, 0.3 mm. For M. avium complex positive patients (MAC group, n = 100; age, 31-89 yrs), the results were PPDs, 10.9; PPD-B, 16.9 mm; PPD-Y, 10.7 mm; PPD-F, 1.6 mm; and PPD-C, 0.3 mm. The M. kansasii positive patients (K group; n = 8) showed results of PPDs, 12.6 mm; PPD-B, 10.7 mm; PPD-Y, 20.8 mm; PPD-F, 0.5 mm; PPD-C, 0.0 mm. The M. fortuitum positive patients (F group; n = 5) had measurements of PPDs, 5.8 mm; PPD-B, 4.4 mm; PPD-Y, 9.8 mm; PPD-F, 17.8 mm; and PPD-C, 16.0 mm. The patients who were previously M. tbc. positive but presently negative patients (pre. TB group; n = 50) showed the following results: PPDs, 16.6 mm; PPD-B, 7.4 mm; and PPD-Y, 10.9 mm. For the patients who were previously M. avium complex positive (previous MAC group; n = 19), the results were PPDs, 10.4 mm; PPD-B, 9.9 mm; and PPD-Y, 7.7 mm. Also considering their frequency distribution curve, with exception of the previous MAC group, the patient groups showed specificity to the PPD of the bacilli detected. The previous MAC group recorded no significant difference in response to PPDs and PPD-B. Strong cross reactions were observed between PPD-F and PPD-C, and moderate reactions between PPDs, PPD-B and PPD-Y. Cross reactions were scarce between PPDs, PPD-B or PPD-Y and PPD-F or PPD-C. Though it is difficult to distinguish cross-reaction and multiple infections, majority of the patients (72-85%) showed greatest response to the PPD that corresponds with the species of bacilli detected. In conclusion, two or more PPDs applied simultaneously can be of aid in diagnosing mycobacteriosis especially in the early stages of the disease. Also, cross-reactions between atypical mycobacteria and PPDs should be taken into consideration when diagnosing infection caused by M. tuberculosis.     

Space charge formation and breakdown in polyethylene influenced by the interface with semiconducting electrodes

This paper deals with the influence of interface between polyethylene and semiconducting electrode on the space charge formation and electrical breakdown. Low‐density polyethylene (LDPE) films attached with different semiconducting electrodes were subjected to the DC breakdown test, and corresponding space charge distribution was measured. A heat treatment to LDPE itself did not bring about a significant change in space charge profile; however, when a semiconducting electrode was hot‐pressed, the impurities would migrate into LDPE at high temperature, leading to the change in space charge profile. Furthermore, it was suggested from the comparison between the results with degassed and as‐received semiconducting electrodes that some carriers relating to impurities in the electrode would move into LDPE under the voltage. In addition, it was shown that the breakdown is not determined by the field at the cathode which can supply sufficient electrons, but by the maximum field across the specimen, suggesting that an increase in conduction current due to the generation and/or injection, rather than the electronic avalanche process, leads to the breakdown. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 19–25, 2002     

Deep hydrodesulfurization of diesel fuel: Design of reaction process and catalysts

Deep hydrodesulfurization (HDS) of diesel fuel oil was designed based on the recognition that alkyl dibenzothiophenes such as 4-methyl-and 4,6-dimethyldibenzothiophenes were the main target for deep HDS. Multi-stage and fractional HDS were very effective to achieve satisfactory HDS in terms of both sulfur level and fluorescent color of desulfurized oil. Catalysts with the selective hydrogenation of refractory sulfur species in major aromatic partners and isomerization-disproportionation of their alkyl groups prior to HDS were also designed to promote the desulfurization of such sulfur species.