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In this study, two kojic acid-methimazole (2-mercapto-1-methylimidazole, MMI, 1) derivatives, 5-hydroxy-2-{[(1-methyl-1H-imidazol-2-yl)thio]methyl}-4H-pyran-4-one (compound 4) and 5-methoxy-2-{[(1-methyl-1H-imidazol-2-yl)thio]methyl}-4H-pyran-4-one (compound 5), were synthesized to examine their inhibitory kinetics on mushroom tyrosinase. Compound 4 exhibited a potent inhibitory effect on monophenolase activity in a dose-dependent manner, with an IC50 value of 0.03 mM. On diphenolase activity, compound 4 exhibited a less inhibitory effect (IC50 = 1.29 mM) but was stronger than kojic acid (IC50 = 1.80 mM). Kinetic analysis indicated that compound 4 was both as a noncompetitive monophenolase and diphenolase inhibitor. By contrast, compound 5 exhibited no inhibitory effects on mushroom tyrosinase activity. The IC50 value of compound 4 for the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was 4.09 mM, being much higher than the IC50 of compound 4 for inhibiting the tyrosinase activity. The results indicated that the antioxidant activity of compound 4 may be partly related to the potent inhibitory effect on mushroom tyrosinase. Compound 4 also exerted a potent inhibitory effect on intracellular melanin formation in B16/F10 murine melanoma cells, and caused no cytotoxicity. Furthermore, compound 4 induced no adverse effects on the Hen's egg test-chorioallantoic membrane (HET-CAM).

Methionine is critical for variety of metabolic processes in biological organisms, acting as a precursor or intermediate for many final products. The last step for the synthesis of methionine is the methylation of homocysteine, which is catalyzed by MetE. Here, we use Salmonella enterica serovar Typhimurium LT2 to study the regulation of the metE+ gene by an anaerobically induced small non-coding RNA-FnrS, the expression of which is strictly dependent on the anaerobic regulator-FNR. The MetE-HA protein was expressed at an increased level in the fnrS- and hfq- deficient strains under anaerobic conditions. The Hfq protein is predicted to stabilize the binding between small RNA(s) and their target mRNA(s). A transcriptional (op) and translational (pr) metE::lacZ fusion gene were separately constructed, with the metE+-promoter fused to a lacZ reporter gene. In an anaerobic environment, the metE::lacZ (pr) fusion gene and reverse transcription-PCR identified that FnrS and/or FNR negatively regulate metE+ mRNA levels in the rich media. Analysis of FnrS revealed a sequence complementary to the 5' mRNA translational initiation region (TIR) of the metE+ gene. Mutation(s) predicted to disrupt base pairing between FnrS and metE+ TIR were constructed in fnrS, and most of those resulted in the loss of repressive activity. When compensatory mutation(s) were made in metE+ 5' TIR to restore base pairing with FnrS, the repressive regulation was completely restored. Therefore, in this study, we identified that in anaerobic phase, there is a repression of metE+ gene expression by FnrS and that base-paring, between both expressive transcripts, plays an important role for this negative regulation.

In this study, we synthesized 4 methimazole (2-mercapto-1-methylimidazole, MMI) derivatives. The kinetics of inhibition on mushroom tyrosinase by methimazole and its derivatives were investigated. The results indicated that tert-butyl 3-methyl-2-sulfanylidene-2,3-dihydro-1H-imidazole-1-carboxylate (compound 3; 3), 2-mercaptoimidazole (MI; compound 1; 1) and MMI (compound 2; 2) significantly inhibited tyrosinase activity in a dose-dependent manner, exhibiting an IC50 value of 1.50 mM, 4.11 mM, and 1.43 mM. However, compound 4 (4), compound 5 (5), and compound 6 (6) exerted no inhibitory effect on mushroom tyrosinase activity. Kinetic analysis indicated that 3 was a noncompetitive tyrosinase inhibitor, whereas both 1 and 2 were exhibited as mixed-type tyrosinase inhibitors. Furthermore, 3 exerted a potent inhibitory effect on intracellular melanin formation in the B16/F10 murine melanoma cells and did not cause cytotoxicity, as 1 and 2 did.

This study reports the preparation of four varieties of water extract from sweet potato leaves from Taiwan, including TNG10, TNG57, TNG66 and YSP, and evaluates their antioxidative activity. The EC50 values (scavenging DPPH radicals) of TNG10, TNG57, TNG66 and YSP were 0.27 ± 0.01, 0.19 ± 0.01, 0.41 ± 0.02, and 0.31 ± 0.02 mg/ml, respectively, on a freeze-dry weight basis. The total phenolic contents of these water extracts were in the order: TNG57 > TNG10 > TNG66 > YSP. The TNG10 and TNG57 extracts exhibited better reducing power and scavenging effects of superoxide radicals than did TNG66 and YSP. At a concentration of 1 mg/ml, TNG10 and TNG57 significantly protected HaCaT cells from H2O2-induced cytotoxicity. The water extracts of YSP had more flavonoids than had those of TNG66 which may have contributed to their higher activity in many antioxidative assays. These results suggest that the water extracts of all four varieties of sweet potato leaves, and especially TNG10 and TNG57, display potent antioxidative effects.

The purpose of this study was to explore whether passive watching of a stroke videotape in the Emergency Department waiting room could be an effective method for patient education. The setting was an urban, inner city teaching hospital. After providing informed consent, subjects were randomized into two arms: those watching a 12-min educational video on stroke developed by the American Stroke Association (video group) and those not undergoing an intervention (control group). Both groups were administered a 13-question quiz covering different stroke-related issues, but only the video group received this same test again after the completion of the educational program. Those enrolled were contacted after 1 month to determine knowledge retention via the same test. Immediately after watching the educational program, participants demonstrated improved knowledge of stroke-related questions, with an increase of test scores from 6.7 +/- 2.5 to 9.5 +/- 2.6 (p0.01). Even at the 1-month follow-up, the video group had significantly higher test scores than the control group. A stroke educational videotape improves the knowledge of this dangerous disease and may be a valuable and relatively low-cost tool for focused patient education in the Emergency Department waiting room.

A comparison is made of predictions of the structural evolution of Al 2 O 3 SiO 2 SiCC refractories during firing and under slag attack made with the FACT computation package, and experimental observations including the development of a decarburised zone, relative wear of different materials and phases present as determined by microstructural and X-ray examination. The corrosion tests were carried out under oxidising conditions and with slags both containing and free of iron oxide. Two different base refractory compositions were used, one containing clay and one without. The additives considered included 5% Al, 10% Si, 5% B 4 C, 5% BN, 5%B 2 O 3 , and 15% Si 3 N 4 . Experimentally, good wear resistance was associated with the predicted content of SiC in the refractory in the as-fired condition. The most effective additives were silicon and B 4 C, whilst the most deleterious was B 2 O 3 . These results are interpreted in terms of the thermochemical predictions, including the variation in oxygen potential with slag attack and it is shown that the materials can be ranked in the same order as observed in the wear tests.

Double-loop networks have been widely studied as architecture for local area networks and it is well-known that the minimum distance diagram of a double-loop network yields an L-shape. Given an N, it is desirable to find a double-loop network DL(N;s1,s2) with its diameter being the minimum among all double-loop networks with N stations. Since the diameter can be easily computed from an L-shape, one method is to start with a desirable L-shape and then asks whether there exist s1 and s2 (also called the steps of the double-loop network) to realize it. In this paper, we propose a simple and efficient algorithm to find s1 and s2, which is based on the Smith normalization method of Aguiló, Esqué and Fiol.

We investigated the relationship between [Ca2+]i, myosin light chain (LC20) phosphorylation and isometric force in guinea pig aortic strips during contractions activated by a thromboxane A2 analogue, (15S)-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5Z, 13E-dienoic acid (U46619). Isometric force and [Ca2+]i were measured simultaneously using preloaded aequorin as the intracellular calcium indicator. LC20 phosphorylation levels were determined by two dimensional polyacrylamide gel electrophoresis in parallel preparations. Contractions induced by U46619 were accompanied by increases in [Ca2+]i and LC20 phosphorylation. The chelation of extracellular calcium with 2.5 mM EGTA significantly inhibited U46619-induced increases in [Ca2+]i, isometric force and LC20 phosphorylation. Steady-state force assumed a similar dependence on LC20 phosphorylation for contractions stimulated by potassium depolarization, alpha 1-adrenergic agonist phenylephrine and U46619 either in the presence or absence of extracellular calcium. On the contrary, the [Ca2+]i/force relation revealed that both U46619 and phenylephrine stimulated greater isometric force at lower [Ca2+]i than did KCl depolarization. The addition of a protein kinase C inhibitor, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), decreases force without significantly affecting either [Ca2+]i or LC20 phosphorylation levels. These results suggest that in guinea pig aortic smooth muscle U46619 increases the calcium sensitivity of the contractile apparatus but does not change the LC20 phosphorylation/force relation in comparison to K+ depolarization. Protein kinase C is activated during U46619-stimulated contraction and might be involved in mechanisms other than LC20 phosphorylation.

Ceramic bodies of mullite composition were prepared from a mixture of calcined alumina and raw kaolin with the addition of bastnasite (rare-earth oxide concentrate) at up to 3% wt and fired at 1400–1650°C. The bastnasite addition effectively enhances mullite formation but the effect diminishes rapidly with increasing temperature. The Al 2 O 3 -rich composition is characteristic of the mullite. The ceramic green compacts with the bastnasite addition can only approx. reach 96% theoretical density at best when heated at 1550–1650°C. The pores in the fired bodies with the bastnasite addition are smaller and uniformly distributed; localized, larger pores are found in the fired bodies without the addition. The slag resistance of the refractories increases slightly with an increasing amount of bastnasite added to the bonding matrix. Bastnasite is not an effective additive for enhancing the slag resistance of steel-plant refractories. The peak temperature in DTA and the valley temperature in the dilatometric analysis, are indicative of mullite formation: the former was found to be 1412°C without bastnasite addition and 1368°C with 3% wt bastnasite addition while the latter was found to be 1420°C without bastnasite addition and 1350°C with 3% wt bastnasite addition.

Slag-resistant tests were performed in fired crucibles made from raw kaolin and calcined alumina powders containing 65, 72, 78 wt% Al2O3 and 65 wt% Al2O3 + 6 wt% Cr2O3. The crucible tests showed that a 2-mm-wide protective layer was visible between slag and non-reaction zones in the 65 wt% Al2O3 crucible and that no such layer appeared in the 72 and 78 wt% Al2O3 crucibles. Reflected light microscopy revealed that in the 65 wt% Al2O3 + 6 wt% Cr2O3 crucible the slag zone was less fluid and the reaction zone less slag penetrative and reactive, as compared with others. The expansion or the shrinkage trend of the bauxite aggregate brick bonded with raw kaolin and calcined alumina powders after more than 3 h reheating at 1500°C depends mainly on the alumina content of the bonding matrix regardless of aggregate mix grading, and previous firing temperatures for green compacts. The continuing positive reheat linear change of bauxite-based, high-alumina, torpedo ladle brick, which promotes mortar joint tightening and retards pencilling slag attack, can be obtained by the combined action of the bonding matrix containing 65 wt% Al2O3 and a lower temperature firing prior to services.