Nucleon and hadron structure changes in the nuclear medium and impact on observables

We review the effect of hadron structure changes in a nuclear medium using the quark-meson coupling (QMC) model, which is based on a mean field description of non-overlapping nucleon (or baryon) bags bound by the self-consistent exchange of scalar and vector mesons. This approach leads to simple scaling relations for the changes of hadron masses in a nuclear medium. It can also be extended to describe finite nuclei, as well as the properties of hypernuclei and meson-nucleus deeply bound states. It is of great interest that the model predicts a variation of the nucleon form factors in nuclear matter. We also study the empirically observed, Bloom-Gilman (quark-hadron) duality. Other applications of the model include subthreshold kaon production in heavy ion collisions, D and D-bar meson production in antiproton-nucleus collisions, and J/Psi suppression. In particular, the modification of the D and D-bar meson properties in nuclear medium can lead to a large J/Psi absorption cross section, which explains the observed J/Psi suppression in relativistic heavy ion collisions.Comment: 143 pages, 77 figures, references added, a review article accepted in Prog. Part. Nucl. Phy

Haplotypes and a Novel Defective Allele of CES2 Found in a Japanese Population

ABSTRACT: Human carboxylesterase 2 (hCE-2) is a member of the serine esterase superfamily and is responsible for hydrolysis of a wide variety of xenobiotic and endogenous esters. hCE-2 also activates an anticancer drug, irinotecan (7-ethyl-10-[4-(1-piperidino)-1-piperidino]-carbonyloxycamptothecin, CPT-11), into its active metabolite, 7-ethyl-10-hydroxycamptothecin (SN-38). In this study, a comprehensive haplotype analysis of the CES2 gene, which encodes hCE-2, in a Japanese population was conducted. Human carboxylesterases are members of the serine esterase superfamily and are responsible for hydrolysis of a wide variety of xenobiotic and endogenous esters. They metabolize esters, thioesters, carbamates, and amides to yield soluble acids and alcohols or amines Although both hCE-1 and hCE-2 show broad substrate specificities, hCE-2 is relatively specific for heroin, cocaine (benzoyl ester), 6-acetylmorphine, procaine, and oxybutynin 1865 camptothecin (SN-38), a topoisomerase inhibitor, by carboxylesterases Previously, 12 exons and their flanking regions of CES2 were sequenced from 153 Japanese subjects, who received irinotecan or steroidal drugs, and 12 novel SNPs, including the nonsynonymous SNP, 100CϾT (Arg 34 Trp), and the SNP at the splice acceptor site of intron 8 (IVS8-2AϾG) were found Materials and Methods Chemicals. Irinotecan, SN-38, and SN-38G were kindly supplied by Yakult Honsha Co. Ltd. (Tokyo, Japan). Patients. A total of 262 Japanese subjects analyzed in this study consisted of 85 patients with allergies who received steroidal drugs and 177 patients with cancer who received irinotecan. The ethical review boards of the National Cancer Center, National Center for Child Health and Development, and National Institute of Health Sciences approved this study. Written informed consent was obtained from all participants. DNA Sequencing. Total genomic DNA was extracted from blood leukocytes or Epstein-Barr virus-transformed lymphocytes and used as a template in the polymerase chain reaction (PCR). Sequence data of the CES2 gene from 72 patients and 81 cancer patients were described previously Linkage Disequilibrium and Haplotype Analyses. LD analysis was performed by the SNPAlyze software (version 5.1; Dynacom Co., Yokohama, Japan), and a pairwise two-dimensional map between SNPs was obtained for the DЈ and rho square (r 2 ) values. All allele frequencies were in HardyWeinberg equilibrium. Some haplotypes were unambiguously assigned in the subjects with homozygous variations at all sites or a heterozygous variation at only one site. Separately, the diplotype configurations (combinations of haplotypes) were inferred by LDSUPPORT software, which determines the posterior probability distribution of the diplotype configuration for each subject on the basis of estimated haplotype frequencies Administration of Irinotecan and Pharmacokinetic Analysis. The demographic data and eligibility criteria for 177 cancer patients who received irinotecan in the National Cancer Center Hospitals (Tokyo and Chiba, Japan) were described elsewhere Each patient received a 90-min i.v. infusion at doses of 60 to 150 mg/m 2 , which varied depending on regimens/coadministered drugs: i.e., irinotecan dosages were 100 or 150 mg/m 2 for monotherapy and combination with 5-FU, 150 mg/m 2 for combination with mitomycin C (MMC), and 60 (or 70) mg/m 2 for combination with platinum anticancer drugs. Heparinized blood was collected before administration of irinotecan and at 0 min (end of infusion), 20 min, 1 h, 2 h, 4 h, 8 h, and 24 h after infusion. Plasma concentrations of irinotecan, SN-38, and SN-38G were determined as described previously Expression of Wild-Type and Variant CES2 Proteins in COS-1 Cells. Expression of wild-type and variant CES2 proteins in COS-1 cells was examined as described previously and ZERO-Dscan software (Raytest, Straubenhardt, Germany). The relative expression levels are shown as the means Ϯ S.D. of three separate transfection experiments. Determination of CES2 mRNA by Real-Time RT-PCR. Total RNA was isolated from transfected COS-1 cells using the RNeasy Mini Kit (QIAGEN, Tokyo, Japan). After RNase-free DNase treatment of samples to minimize plasmid DNA contamination, first-strand cDNA was prepared from 1 g of total RNA using the High-Capacity cDNA Archive Kit (Applied Biosystems, Foster City, CA) with random primers. Real-time PCR assays were performed with the ABI7500 Real Time PCR System (Applied Biosystems) using the TaqMan Gene Expression Assay for CES2 (Hs01077945_m1; Applied Biosystems) according to the manufacturer's instructions. The relative mRNA levels were determined using calibration curves obtained from serial dilutions of the pooled wild-type CES2 cDNA. Samples without reverse transcriptase were routinely included in the RT-PCR reactions to measure possible contributions of contaminating DNA, which was usually less than 1% of the mRNA-derived amplification. Transcripts of ␤-actin were quantified as internal controls using TaqMan ␤-Actin Control Reagent (Applied Biosystems), and normalization of CES2 mRNA levels were based on ␤-actin concentrations. Enzyme Assay. CPT-11 hydrolyzing activity of the postmitochondrial supernatants (microsomal fraction plus cytosol) was assayed over the substrate concentration range of 0.25 to 50 M as described previously Statistical Analysis. Statistical analysis of the differences in the AUC ratios among CES2 diplotypes, coadministered drugs. or irinotecan dosages was performed using the Kruskal-Wallis test, Mann-Whitney test, or Spearman rank correlation test (Prism 4.0, GraphPad Software, Inc., San Diego, CA). The t test (Prism 4.0) was applied to the comparison of the average values of protein expression and mRNA levels between wild-type and variant CES2. Results CES2 Variations Detected in a Japanese Population. Previously, the promoter region, all 12 exons, and their flanking introns of the CES2 gene were sequenced from 72 allergic patients and 81 cancer patients and resulted in the identification of 12 novel SNPs The nonsynonymous SNP 424GϾA (V142M) reported by our group LD and Haplotype Analysis. Using the detected SNPs, LD analysis was performed, and the pairwise values of r 2 and DЈ were obtained. A perfect linkage (r 2 ϭ 1.00) was observed between SNPs Ϫ363CϾG and IVS10-87GϾA. A close association (r 2 ϭ 0.85) was found between SNPs IVS10-108GϾA and 1749AϾG. Other associations were much lower (r 2 Ͻ 0.1). Therefore, the entire CES2 gene was analyzed as one LD block. The determined/inferred haplotypes are summarized i

Plasma-Assisted Synthesis of Multicomponent Nanoparticles Containing Carbon, Tungsten Carbide and Silver as Multifunctional Filler for Polylactic Acid Composite Films

Multicomponent nanoparticles containing carbon, tungsten carbide and silver (carbon-WC-Ag nanoparticles) were simply synthesized via in-liquid electrical discharge plasma, the so-called solution plasma process, by using tungsten electrodes immersed in palm oil containing droplets of AgNO3 solution as carbon and silver precursors, respectively. The atomic ratio of carbon:W:Ag in carbon-WC-Ag nanoparticles was 20:1:3. FE-SEM images revealed that the synthesized carbon-WC-Ag nanoparticles with particle sizes in the range of 20–400 nm had a spherical shape with a bumpy surface. TEM images of carbon-WC-Ag nanoparticles showed that tungsten carbide nanoparticles (WCNPs) and silver nanoparticles (AgNPs) with average particle sizes of 3.46 nm and 72.74 nm, respectively, were dispersed in amorphous carbon. The carbon-WC-Ag nanoparticles were used as multifunctional fillers for the preparation of polylactic acid (PLA) composite films, i.e., PLA/carbon-WC-Ag, by solution casting. Interestingly, the coexistence of WCNPs and AgNPs in carbon-WC-Ag nanoparticles provided a benefit for the co-nucleation ability of WCNPs and AgNPs, resulting in enhanced crystallization of PLA, as evidenced by the reduction in the cold crystallization temperature of PLA. At the low content of 1.23 wt% carbon-WC-Ag nanoparticles, the Young’s modulus and tensile strength of PLA/carbon-WC-Ag composite films were increased to 25.12% and 46.08%, respectively. Moreover, the PLA/carbon-WC-Ag composite films possessed antibacterial activities

Photoinduced Glycerol Oxidation over Plasmonic Au and AuM (M = Pt, Pd and Bi) Nanoparticle-Decorated TiO2 Photocatalysts

In this study, sol-immobilization was used to prepare gold nanoparticle (Au NP)-decorated titanium dioxide (TiO2) photocatalysts at different Au weight % (wt. %) loading (Aux/TiO2, where x is the Au wt. %) and Au–M NP-decorated TiO2 photocatalysts (Au3M3/TiO2), where M is bismuth (Bi), platinum (Pt) or palladium (Pd) at 3 wt. %. The Aux/TiO2 photocatalysts exhibited a stronger visible light absorption than the parent TiO2 due to the localized surface plasmon resonance effect. Increasing the Au content from 1 wt. % to 7 wt. % led to increased visible light absorption due to the increasing presence of defective structures that were capable of enhancing the photocatalytic activity of the as-prepared catalyst. The addition of Pt and Pd coupled with the Au3/TiO2 to form Au3M3/TiO2 improved the photocatalytic activity of the Au3/TiO2 photocatalyst by maximizing their light-absorption property. The Au3/TiO2, Au3Pt3/TiO2 and Au3Pd3/TiO2 photocatalysts promoted the formation of glyceraldehyde from glycerol as the principle product, while Au3Bi3/TiO2 facilitated glycolaldehyde formation as the major product. Among all the prepared photocatalysts, Au3Pd3/TiO2 exhibited the highest photocatalytic activity with a 98.75% glycerol conversion at 24 h of reaction time

Exotic shapes of gold nanoparticles synthesized using plasma in aqueous solution

Gold nanoparticles with exotic shapes, such as triangle, pentagon, and hexagon, have been synthesized by glow discharge in aqueous solutions. A pulsed power supply was used to generate discharges in the aqueous solutions. Pulse width and frequency were 2 µs and 15 kHz, respectively. Discharges were generated at applied voltages of 1600 and 3200 V. The shapes of the gold nanoparticles and electron diffraction patterns were observed by transmission electron microscopy. The nanoparticles obtained were about 20 nm in diameter. In particular, at the higher voltage of 3200 V, nanoparticles with anisotropic shapes were synthesized. In the initial stages of synthesis, diameter decreased with discharge time as the nanoparticles redissolved in the solution. After discharge for 25 min, nanoparticles with anisotropic shapes appeared. This discharge led to the generation of H_2O_2 and a decrease in pH as a result of the consumption of OH radicals during the generation of H_2O_2 and electron donation of H radicals to the solution. After the pH stopped decreasing, H radicals mainly reacted as a reducing agent. The decrease in pH allowed redissolution of the gold nanoparticles. The gold dust particles that were not completely dissolved acted as new seeds for nucleation. Thus, the two reaction steps, nucleation and nuclear growth, occur during the formation of gold nanoparticles with exotic shapes