Semifield planes with a transitive autotopism group

Research supported in part by NSF Grant No. DMS-9107372     

Simultaneous bidirectional message transmission in a chaos-based communication scheme

We introduce a chaos-based communication scheme allowing for bidirectional exchange of information. Coupling [corrected] two semiconductor lasers through a partially transparent optical mirror, placed in the pathway connecting the lasers [corrected] delay dynamics is induced in both lasers. We numerically demonstrate that this dynamics can be identically synchronized, and moreover, information introduced on both ends of the link can be simultaneously transmitted. This scheme allows one to negotiate a key through a public channel.     

Serum exosomal microRNAs as novel biomarkers for hepatocellular carcinoma

Recent studies have shown that circulating microRNAs are a potential biomarker in various types of malignancies. The aim of this study was to investigate the feasibility of using serum exosomal microRNAs as novel serological biomarkers for hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). We measured the serum exosomal microRNAs and serum circulating microRNAs in patients with CHB (n=20), liver cirrhosis (LC) (n=20) and HCC (n=20). Serum exosomal microRNA was extracted from 500 μl of serum using an Exosome RNA Isolation kit. The expression levels of microRNAs were quantified by real-time PCR. The expression levels of selected microRNAs were normalized to Caenorhabditis elegans microRNA (Cel-miR-39). The serum levels of exosomal miR-18a, miR-221, miR-222 and miR-224 were significantly higher in patients with HCC than those with CHB or LC (P<0.05). Further, the serum levels of exosomal miR-101, miR-106b, miR-122 and miR-195 were lower in patients with HCC than in patients with CHB (P=0.014, P<0.001, P<0.001 and P<0.001, respectively). There was no significant difference in the levels of miR-21 and miR-93 among the three groups. Additionally, the serum levels of circulating microRNAs showed a smaller difference between HCC and either CHB or LC. This study suggests that serum exosomal microRNAs may be used as novel serological biomarkers for HCC.     

Synthesis of MgB4O7 and Li2B4O7 crystals by proteic sol–gel and Pechini methods

Journal of Sol-Gel Science and Technology - Magnesium-tetraborates and lithium-tetraborates are excellent detectors for ionizing radiation. However, manufacturing these crystalline structures is...     

<Emphasis Type="Italic">p</Emphasis>-adic valuation of exponential sums associated to trinomials and some consequences

In this paper, we compute the p-adic valuation of exponential sums associated to trinomials \(F\left( X \right) = a{X^{{d_1}}} + b{X^{{d_2}}} + c{X^{{d_3}}}\) over Fp. As a byproduct of our results, we obtain restrictions for permutation polynomials of type \(a{X^{{d_1}}} + b{X^{{d_2}}} + c{X^{{d_3}}}\) over F_p.     

On eight-dimensional unital division algebras over finite fields

The purpose of this paper is to investigate the eight-dimensional non-associative unital division algebras {0}≠A over finite fields, admitting elementary abelian 2-group of automorphisms E≤Aut(A), of order 8, using tools from algebraic geometry.     

Catalytic and Thermodynamic Properties of a Tannase Produced by Aspergillus niger GH1 Grown on Polyurethane Foam

Tannase is an inducible enzyme with important applications in the food and pharmaceutical industries. This enzyme was produced by the fungus Aspergillus niger GH1 under solid-state fermentation using polyurethane foam as solid support and tannic acid as sole carbon source and tannase inducer. Physicochemical properties of A. niger tannase were characterized, and the kinetic and thermodynamics parameters on methyl gallate hydrolysis were evaluated. The enzyme was stable in a pH range of 2-8 and a functional temperature range of 25-65 °C. The highest k(cat) value was 2,611.10 s(-1) at 65 °C. Tannase had more affinity for methyl gallate at 45 °C with a K(M) value of 1.82 mM and an efficiency of hydrolysis (k(cat)/K(M)) of 330.01 s(-1) mM(-1). The lowest E(a) value was found to be 21.38 kJ/mol at 4.4 mM of methyl gallate. The lowest free energy of Gibbs (ΔG) and enthalpy (ΔH) were found to be 64.86 and 18.56 kJ/mol, respectively. Entropy (ΔS) was -0.22 kJ/mol K. Results suggest that the A. niger GH1 tannase is an attractive enzyme for industrial applications due its catalytic and thermodynamical properties.     

Fermentation of Korean Red Ginseng by Lactobacillus plantarum M-2 and Its Immunological Activities

We investigated ginsenoside transformation by fermentation of red ginseng with Lactobacillus plantarum M-2. We also examined the anti-metastasis and immune-stimulating activities of EtOH extracts of fermented red ginseng (FRG-E) in animal and human subjects. Total sugar decreased from 85.5 mg mL(-1) to 44.1 mg mL(-1) with increasing culture time during the fermentation with L. plantarum M-2. Uronic acid content reached a maximum level (534.3 μg mL(-1)) at 3 days of fermentation and decreased thereafter. Ginsenoside metabolites increased from 4,637.0 to 7,581.1 μg mL(-1) after 4 days. The prophylactic intraperitoneal injection of FRG-E (500 μg mouse(-1)) inhibited lung metastasis about 81.1%, while the inhibitory effect against tumor metastasis by treatment of EtOH extract from non-fermented red ginseng (NFRG-E) was 66.9%. Immunoglobulin A (IgA) and G (IgG) levels in the serum of healthy subjects were higher after FRG-E administration than at baseline, whereas NFRG-E induced reductions of these variables related to immunity. At 1 week, the change in IgA level by FRG-E (5.14 mg mL(-1)) was significantly higher than that by NFRG-E (-14.50 mg mL(-1); p < 0.05). It was concluded that the immunological activities of FRG-E were higher than those of NFRG-E, indicating that fermentation helped enhance the immunological activities of red ginseng.