15-Deoxy-delta12,14-PGJ2 inhibits IL-6-induced Stat3 phosphorylation in lymphocytes

15-deoxy-delta(12,14)-PGJ(2)(15d-PGJ(2)) is a natural ligand that activates the peroxisome proliferators-activated receptor (PPAR) gamma, a member of nuclear receptor family implicated in regulation of lipid metabolism and adipocyte differentiation. Recent studies have shown that 15d-PGJ(2) is the potent anti-inflammatory agent functioning via PPARgamma-dependent and -independent mechanisms. Most postulated mechanisms for anti-inflammatory action of PPARgamma agonists are involved in inhibiting NF-kappaB signaling pathway. We examined the possibility that IL-6 signaling via the Jak-Stat pathway is modulated by 15d-PGJ(2) in lymphocytes and also examined whether the inhibition of IL-6 signaling is dependent of PPARgamma. 15d-PGJ(2) blocked IL-6 induced Stat1 and Stat3 activation in primary human lymphocytes, Jurkat cells and immortalized rheumatoid arthritis B cells. Inhibition of IL-6 signaling was induced rapidly within 15 min after treatment of 15d-PGJ(2). Other PPARgamma-agonists, such as troglitazone and ciglitazone, did not inhibit IL-6 signaling, indicating that 15d-PGJ(2) affect the IL-6-induced Jak-Stat signaling pathway via PPARgamma-independent mechanism. Although cycloheximide reversed 15d-PGJ(2)-mediated inhibition of Stat3 activation, actinomycin D had no effect on 15d-PGJ(2)-mediated inhibition of IL-6 signaling, indicating that inhibition of IL-6 signaling occur independent of de novo gene expression. These results show that 15d-PGJ(2) specifically inhibit Jak-Stat signaling pathway in lymphocytes, and suggest that 15d-PGJ(2) may regulate inflammatory reactions through the modulation of different signaling pathway other than NF-kappaB in lymphocytes.     

Production of ceramide with Saccharomyces cerevisiae

The possibility of producing the biologically active material of the skin, ceramide, was studied using yeasts. The yeast strain that produced the most ceramide, Saccharomyces cerevisiae (KCCM 50515), was selected, and the optimal conditions for ceramide production were determined using shakeflask culture and batch fermentation. By measuring the production rate of ceramide at various pH values and temperatures, the optimal conditions for ceramide production were found to be pH 6.0 and 30°C. When heat shock was applied to the cells for 1 h by increasing the culture temperature from 30 to 40°C after cell growth, the amount of ceramide produced was increased 5.9-fold. A cell growth and ceramide production model was developed with Monod kinetics and the Leudecking-Piret model. It showed that ceramide production was increased when the cells were in the stationary phase.     

Temperature-controlled growth of ZnO nanowires and nanoplates in the temperature range 250-300 degrees C

Starting from a mixture of Zn and BiI3, we grew nanowires and nanoplates on an oxidized Si substrate at relatively low temperatures of 250 and 300 degrees C, respectively. The ZnO nanowires had diameters of approximately 40 nm and grew along the [110] direction rather than the conventional [0001] direction. The nanoplates had thicknesses of approximately 40 nm and lateral dimensions of 3-4 microm. The growth of both the nanowires and nanoplates is dominated by the synergy of vapor-liquid-solid (VLS) and direction conducting. Analysis of photoluminescence spectra suggested that the nanoplates contain more oxygen vacancies and have higher surface-to-volume ratios than the nanowires. The present results clearly demonstrate that the shapes of ZnO nanostructures formed by using BiI3 can be controlled by varying the temperature in the range 250-300 degrees C.     

Highly sensitive electrochemical detection of proteins using aptamer-coated gold nanoparticles and surface enzyme reactions

A novel electrochemical detection methodology is described for the femtomolar detection of proteins which utilizes both DNA aptamer-functionalized nanoparticles and a surface enzymatic reaction. Immunoglobulin E (IgE) was used as a model protein biomarker, which possesses two distinct epitopes for antibody (anti-IgE) and DNA aptamer binding. A surface sandwich assay format was utilized involving the specific adsorption of IgE onto a gold electrode surface that was pre-modified with a monolayer of aptamer-nanoparticle conjugates followed by the specific interaction of alkaline phosphatase (ALP) conjugated anti-IgE. To clearly demonstrate the signal enhancement associated with nanoparticle use, anodic current measurements of the ALP catalyzed oxidation of the enzyme substrate 4-aminophenylphosphate (APP) were also compared with electrode surfaces upon which the aptamer was directly attached. The detection of an unlabelled protein at concentrations as low as 5 fM is a significant improvement compared to conventional electrochemical-based immunoassay approaches and provides a foundation for the practical use and incorporation of nanoparticle-enhanced detection into electrochemical biosensing technologies.     

Minimum orders of eulerian oriented digraphs with given diameter

A digraph D is oriented if it does not contain 2-cycles.If an oriented digraph D has a directed eulerian path,it is an oriented eulerian digraph.In this paper,when an oriented eulerian digraph D has minimum out-degree 2 and a diameter d,we find the minimum order of D.In addition,when D is 2-regular with diameter 4m(m ≥ 2),we classify the extremal cases.     

Design of hybrid optical waveguide with a 90° bend structure for high density photonics integrated circuits

A hybrid optical waveguide having a 90° sharp bend structure, composed of a dielectric straight waveguide, tapered dielectric strip waveguide, and microscale metal gap waveguide, is proposed and simulated to improve the efficiency of light coupling between dielectric and plasmonic waveguides. Our simulation result is a critical step for the hybrid integration of plasmonic components with conventional dielectric components.     

Determination of226Ra in environmental samples using high-resolution inductively coupled plasma mass spectrometry

A time-saving and accurate technique for determining²²⁶Ra in groundwater and soil was examined, using high-resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS). The technique was applied to the determination of²²⁶Ra in groundwater and soil samples and compared with the conventional liquid scintillation counting method. This technique was capable of completing²²⁶Ra counting within 3 minutes, without the in-growth period to allow radon and its progeny to achieve secular equilibrium with the parent²²⁶Ra. The detection limits of HR-ICP-MS for²²⁶Ra in groundwater and soil were 0.19 mBq·1⁻¹ and 0.75 Bq·kg⁻¹, respectively, which were about 10 times lower than that of the liquid scintillation counter. The results obtained from HR-ICP-MS in groundwater and soil were in accordance with those of LSC within a relative error of about 13%.     

Golmaenone, a new diketopiperazine alkaloid from the marine-derived fungus Aspergillus sp

A new diketopiperazine alkaloid, golmaenone (1). and related alkaloids, neoechinulin A (2). and L-alanyl-L-tryptophan anhydride (3). have been isolated from the culture broth of the marine-derived fungus Aspergillus sp. The structure and absolute stereochemistry of the new compound (1). was assigned by spectroscopic methods and the advanced Marfey's method. Compounds 1 and 2 exhibited a significant radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with IC(50) values of 20 and 24 microM, respectively, which are similar to the positive control, ascorbic acid (IC(50), 20 microM). Compounds 1 and 2 also showed an ultraviolet-A (UV-A) (320--390 nm) protecting activity with ED(50) values of 90 and 170 microM, respectively, which are more active than oxybenzone (ED(50), 350 microM) currently being used as sunscreen.     

Environmental radiation monitoring in Korea

Environmental radiation monitoring in Korea can be categorized as (1) nationwide monitoring program and (2) monitoring program for nuclear facilities. The former is designed to quickly detect any abnormal situation in environmental radioactivity levels. The latter has the objective of evaluating environmental radioactivity levels resulting from the operation of nuclear facilities. This paper describes the two monitoring programs, how they are implemented, items of being measured, analytical techniques, quality control programs and R&D activities associated with the monitoring. Also, some of the latest data obtained by the monitoring programs are introduced.     

Chiral hyperbags

We construct and studySU (3) chiral bags (called chiral hyperbags) in the scheme of collective-coordinate quantization with chiral symmetry breaking treated as perturbation. We show how the Wess-Zumino constraint arises from the quark-bag sector, complementing the soliton sector, in a manner analogous to what happens in (1+1) dimensional chiral bags. Due to the Wess-Zumino term, all the quantum numbers — baryon charge, isopin, angular momentum, hypercharge etc. are fractionized in a prescribed manner. One notable aspect of the fractionization is that for all ranges of bag radius, there is alwaysmore angular momentum lodged in the soliton sector than in the quark sector. It is shown thatwithin the scheme we have adopted, the symmetry breaking termobstructs the Cheshire Cat principle and that consequently when strange quarks are present, the baryons (i.e. hyperons) favor a bigger bag (say R ? 1 fm) than non-strange baryons; this confirms a phenomenological argument put forward some time ago by Brown, Klimpt, Rho and Weise (at least in the collective-coordinate scheme). Our approach allows us to calculate the strangeness content of the proton — a highly topical issue — and we find that while a perturbative treatment of the symmetry breaking term can be made to work (for a big bag) for hyperon spectroscopy, the strangeness content of the proton is insensitive to the bag radius; for relevant ranges of bag radius, the ¯ss admixture stays significant, say, ?19%. This result is in stark contrast to the Callan-Klebanov Skyrmion — a remarkably successful model for hyperons — which predicts only about 3%. A subtle role of the Wess-Zumino term is suggested.