Highly active methanol decomposition catalyst derived from Pd‐hydrotalcite dispersed on mesoporous silica

Pd‐hydrotalcite (abbreviated as Pd(HT)) was dispersed on HMS (hexagonal mesoporous silica) by synthesizing Pd(HT) in an HMS suspension, and the resultant product (Pd(HT)/HMS) was used as a catalyst precursor for methanol decomposition to synthesis gas. The IR spectra of Pd(HT)/HMS showed all the bands of Pd(HT) and HMS with little shift, which indicated that Pd(HT) was synthesized in the Pd(HT)/HMS. Pd(HT)/HMS did not show the XRD pattern of Pd(HT) when the mass ratio of Pd(HT) to HMS was from 2/1 to 1/2. This indicated that Pd(HT) was formed in very small particles in the Pd(HT)/HMS after dispersion. Two endothermic peaks of Pd(HT) in the DTA curve shifted to lower temperatures in the Pd(HT)/HMS because the small Pd(HT) particles formed in the Pd(HT)/HMS were easily collapsed by heat treatment. Pd(HT)/HMS was thermally decomposed and reduced to form a supported Pd catalyst (abbreviated Pd(Mg(Al)O)/HMS) for methanol decomposition. Pd(Mg(Al)O)/HMS at 3.6 wt% showed a 52.5% conversion which was much higher than those over 3.6 wt% Pd(Mg(Al)O) (34.7%) and 3.6 wt% Pd/HMS (13.7%) for methanol decomposition at 523 K. The conversions of methanol over Pd(Mg(Al)O) and Pd/HMS increased with the increase in Pd loadings from 3.6 to 15 wt% and decreased when the Pd loadings were over 15 wt%. In contrast, the conversion over Pd(Mg(Al)O)/HMS increased with the increase in Pd loading even when the Pd loading was up to 30%. 30 wt% Pd(Mg(Al)O)/HMS showed a 91.7% conversion which was about twice that over 15 wt% Pd(Mg(Al)O) (47.1%) at 523 K. The Pd(Mg(Al)O)/HMS catalyst showed a larger BET surface area and Pd metal surface area than those of Pd(Mg(Al)O). By characterization using XPS analyses, the metal–support interaction between small Pd and small Mg(Al)O became stronger in the Pd(Mg(Al)O)/HMS catalyst. Large surface area, high Pd dispersion and strong metal–support interaction caused the high catalytic activity for methanol decomposition to synthesis gas over the Pd(Mg(Al)O)/HMS catalyst. This revised version was published online in July 2006 with corrections to the Cover Date.     

Eicosapentaenoic Acid Supplementation for Chronic Hepatitis C Patients During Combination Therapy of Pegylated Interferon α-2b and Ribavirin

Eicosapentaenoic acid (EPA) (1.8 g/day) was administered to 12 chronic hepatitis C patients receiving combination therapy of pegylated interferon (PEG-IFN) α-2b and ribavirin for 48 weeks (EPA group). Twelve patients were not administered EPA (control group). All patients also received vitamin E and C (300, 600 mg/day, respectively) during the therapy. Serum alanine aminotransferase improved to a normal level in 8 of 12 patients from the EPA group and 6 of 12 patients from the control group after 12 weeks. Lymphocyte counts decreased significantly after 8 weeks in the control group, but not the EPA group. T-helper (Th) 1 decreased after 4 weeks in the control group, but not in the EPA group (two-way ANOVA; P < 0.05). Th1/Th2 ratios were elevated in 9 of 12 patients in the EPA group, and 3 out of 12 in the control group (P < 0.05) after 8 weeks. After 12 weeks, the arachidonic acid/EPA molar ratio of erythrocyte membrane phospholipid correlated negatively with the leukocyte count (n = 24, r = −0.439, P < 0.05) and the neutrophil count (n = 24, r = −0.671, P < 0.02). The hemoglobin level improved after 48 weeks compared with 24 weeks in only the EPA group. These findings suggest that EPA supplementation may be useful in therapy for chronic hepatitis C.     

Role of Neuroinflammation and Blood-Brain Barrier Permutability on Migraine

Currently, migraine is treated mainly by targeting calcitonin gene-related peptides, although the efficacy of this method is limited and new treatment strategies are desired. Neuroinflammation has been implicated in the pathogenesis of migraine. In patients with migraine, peripheral levels of pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α, are known to be increased. Additionally, animal models of headache have demonstrated that immunological responses associated with cytokines are involved in the pathogenesis of migraine. Furthermore, these inflammatory mediators might alter the function of tight junctions in brain vascular endothelial cells in animal models, but not in human patients. Based on clinical findings showing elevated IL-1β, and experimental findings involving IL-1β and both the peripheral trigeminal ganglion and central trigeminal vascular pathways, regulation of the Il-1β/IL-1 receptor type 1 axis might lead to new treatments for migraine. However, the integrity of the blood-brain barrier is not expected to be affected during attacks in patients with migraine.     

Stability of vitamin A in oil-in-water-in-oil-type multiple emulsions

The stabilityof vitamin A was studied in thee different emulsions: oil-in-water (O/W), water-in-oil (W/O), and oil-in-water-in-oil (O/W/O). The stability of retinol (vitamin A alcohol) in the O/W/O emulsion was the highest among the thee types of emulsions; remaining percentages at 50°C after 4 wk in the O/W/O, W/O, and O/W emulsions were 56.9, 45.7, and 32.3, respectively. With increasing peroxide value of O/W and W/O emulsifiers, the remaining percentage of vitamin A palmitate and retinol in the emulsions decreased significantly, indicating that peroxides in the formulae accelerate the decomposition of vitamin A. Organophilic clay mineral (an oil gelling agent and a W/O emulsifier) also affected the stability of retinol; synthesized saponite was better than naturally occurring bentonite for retinol stability. The stability of retinol in the O/W/O emulsion increased with increasing inner oil phase ratio (φ_i), whereas in O/W it was unaffected by φ_i. Encapsulation percent of retinol in the O/W/O emulsion, the ratio of retinol in the inner oil phase to the total amount in the emulsion, increased with increasing φ_i. The remaining percent of retinol in the O/W/O emulsion was in excellent agreement with encapsulation percent, suggesting that retinol in the inner oil phase is more stable than that in the outer oil phase. Addition of antioxidants (tert-butylhydroxytoluene, sodium ascorbate, and EDTA) to the O/W/O emulsion improved the stability of retinol up to 77.1% at 50°C after 4 wk. We conclude that the O/W/O emulsion is a useful formula to stabilize vitamin A.     

Variation in the Chain‐length Distribution Profiles of Endosperm Starch from Triticum and Aegilops Species

The baseline variation data on the chain‐length distribution profiles of endosperm starch were acquired for use as a criterion for variation among bread wheat (Triticum aestivum L.) cultivars/lines. A total of 126 starch samples isolated from closely related species belonging to the Triticum‐Aegilops group, i.e., five Triticum and 22 Aegilops species, were examined. Their side‐chains were debranched by isoamylase and chain‐length distribution profiles were determined by high‐performance anion exchange chromatography with pulsed amperometric detection (HPAEC‐PAD). An averaged chain‐length distribution profile calculated from all data indicated that the most abundant side‐chain had a degree of polymerization (DP) of 11 and its proportion based on relative peak area was 7.5%. The side‐chains were classified into four groups, and the average proportions of each group were as follows; DP 6–12, 28.5% (range 26.3–30.9%); DP 13–24, 48.6% (46.2–50.8%); DP 25–36, 13.7% (12.8–15.2%) and DP ≥37, 8.9% (7.2–10.6%). The chain‐length distribution profiles of Triticum and Aegilops species were essentially similar and no peculiar profile was observed. The range of the variation in the proportion of side‐chain groups, however, was comparable to the difference between waxy and non‐waxy bread wheat starches and among starches from wheat grown at different temperatures; this would affect the gelatinization and retrogradation properties of starch.