Re-Hardening of Hadron Transverse Mass Spectra in Relativistic Heavy-Ion Collisions

We analyze the spectra of pions and protons in heavy-ion collisions at relativistic energies from 2 A GeV to 65+65 A GeV by using a jet-implemented hadron-string cascade model. In this energy region, hadron transverse mass spectra first show softening until SPS energies, and re-hardening may emerge at RHIC energies. Since hadronic matter is expected to show only softening at higher energy densities, this re-hardening of spectra can be interpreted as a good signature of the quark-gluon plasma formation.Comment: 10 pages, 3 figures, 1 table, Poster presentation at QM2001, Revised to correct latex error in citation on April 6, 200

When ring makes the difference: coordination properties of Cu2+/Cu+ complexes with sulfur-pendant polyazamacrocycles for radiopharmaceutical applications

Three polyazamacrocyclic ligands, i.e. 1,5,9-tris[2-(methylsulfanyl)ethyl]-1,5,9-triazacyclododecane (TACD3S), 1,4,7,10-tetrakis[2-(methylsulfanyl)ethyl]-1,4,7,10-tetrazacyclotridecane (TRI4S) and 1,4,8,11-tetrakis[2-(methylsulfanyl)ethyl]-1,4,8,11-tetrazacyclotetradecane (TE4S), were considered as potential chelators for the medically relevant copper radioisotopes. The ligands have been synthesized through facile, single-step reactions, and their acidity constants have been measured in aqueous solution at 25 degrees C. The kinetic, thermodynamic, electrochemical and structural properties of their Cu2+ and Cu+ complexes were investigated in aqueous solution at 25 degrees C using spectroscopic (UV-Visible, EPR, NMR) and electrochemical techniques (pH-potentiometric titrations, cyclic voltammetry and electrolysis). TACD3S was demonstrated to be unable to stabilize Cu2+, whereas for TRI4S and TE4S the formation of stable monocupric (CuL2+) and monocuprous (CuL+) complexes was detected. TRI4S coordinates Cu(2+)via a [4N] and a [4N]S array of donor atoms while with TE4S only the latter geometry exists. The thermodynamic stability and the kinetic inertness of the copper complexes formed by TACD3S, TRI4S and TE4S were compared with those previously reported for 1,4,7,10-tetrakis-[2-(methylsulfanyl)ethyl]-1,4,7,10-tetrazacyclododecane (DO4S) to unravel the influence of the ring size and the nitrogen donor array on the copper chelation properties of these sulfur-rich macrocycles. The copresence of four nitrogen atoms is an essential feature to allow effective copper coordination when a 12-member ring is employed, as the Cu2+-DO4S complexes were far more stable than those of Cu2+-TACD3S. Furthermore, the larger ring size of TRI4S and TE4S, when compared to DO4S, progressively increases the rate of the Cu2+ complexation reactions but decreases the thermodynamic stability of the Cu2+ complexes. Despite this, the ability of TRI4S and TE4S to stably accommodate both copper oxidation states makes them very attractive for application in nuclear medicine as they could avoid the demetallation after the biologically triggered Cu2+/Cu+ reduction

SPRR2A enhances p53 deacetylation through HDAC1 and down regulates p21 promoter activity

Background: Small proline rich protein (SPRR) 2A is one of 14 SPRR genes that encodes for a skin cross-linking protein, which confers structural integrity to the cornified keratinocyte cell envelope. New evidence, however, shows that SPRR2A is also a critical stress and wound repair modulator: it enables a variety of barrier epithelia to transiently acquire mesenchymal characteristics (EMT) and simultaneously quench reactive oxygen species during wound repair responses. p53 is also widely recognized as the node in cellular stress responses that inhibits EMT and triggers cell-cycle arrest, apoptosis, and cellular senescence. Since some p53-directed processes would seem to impede wound repair of barrier epithelia, we hypothesized that SPRR2A up regulation might counteract these effects and enable/promote wound repair under stressful environmental conditions.Results: Using a well characterized cholangiocarcinoma cell line we show that levels of SPRR2A expression, similar to that seen during stressful biliary wound repair responses, disrupts acetylation and subsequent p53 transcriptional activity. p53 deacetylation is accomplished via two distinct, but possibly related, mechanisms: 1) a reduction of p300 acetylation, thereby interfering with p300-p53 binding and subsequent p300 acetylation of K382 in p53; and 2) an increase in histone deacetylase 1 (HDAC1) mRNA and protein expression. The p300 CH3 domain is essential for both the autoacetylation of p300 and transference of the acetyl group to p53 and HDAC1 is a component of several non-p300 complexes that enhance p53 deacetylation, ubiquitination, and proteosomal degradation. HDAC1 can also bind the p300-CH3 domain, regulating p300 acetylation and interfering with p300 mediated p53 acetylation. The importance of this pathway is illustrated by showing complete restoration of p53 acetylation and partial restoration of p300 acetylation by treating SPRR2A expressing cells with HDAC1 siRNA.Conclusion: Up-regulation of SPRR2A, similar to that seen during barrier epithelia wound repair responses reduces p53 acetylation by interfering with p300-p53 interactions and by increasing HDAC1 expression. SPRR2A, therefore, functions as a suppressor of p53-dependent transcriptional activity, which otherwise might impede cellular processes needed for epithelial wound repair responses such as EMT. © 2012 Mizuguchi et al.; licensee BioMed Central Ltd

Nonextensive statistical effects in the quark-gluon plasma formation at relativistic heavy-ion collisions energies

We investigate the relativistic equation of state of hadronic matter and quark-gluon plasma at finite temperature and baryon density in the framework of the non-extensive statistical mechanics, characterized by power-law quantum distributions. We impose the Gibbs conditions on the global conservation of baryon number, electric charge and strangeness number. For the hadronic phase, we study an extended relativistic mean-field theoretical model with the inclusion of strange particles (hyperons and mesons). For the quark sector, we employ an extended MIT-Bag model. In this context we focus on the relevance of non-extensive effects in the presence of strange matter.Comment: 12 pages, 5 figure

Sexual Knowledge, attitudes and behaviors among unmarried migrant female workers in China: a comparative analysis

<p>Abstract</p> <p>Background</p> <p>In recent years, many studies have focused on adolescent's sex-related issues in China. However, there have been few studies of unmarried migrant females' sexual knowledge, attitudes and behaviors, which is important for sexual health education and promotion.</p> <p>Methods</p> <p>A sample of 5156 unmarried migrant female workers was selected from three manufacturing factories, two located in Shenzhen and one in Guangzhou, China. Demographic data, sexual knowledge, attitudes and behaviors were assessed by self-administered questionnaires. Multivariate logistic regression analysis was conducted to examine the factors associated with premarital sexual intercourse.</p> <p>Results</p> <p>The average age of the unmarried female workers included in the sample was 20.2 years, and majority of them showed a low level of sex-related knowledge. Females from the west of China demonstrated a significant lower level of sex-related knowledge than those from the eastern or central provinces (<it>p </it>< 0.05). Approximately 13% of participants held a favorable attitude towards premarital sexual intercourse, and youths from the east/central were more likely to have favorable attitudes compared with those from the west (<it>p </it>< 0.05). About 17.0% of the unmarried female workers reported having engaged in premarital sexual intercourse, and females from the east/central were more likely to have experienced premarital sexual intercourse than those from the west (<it>p </it>< 0.05). Multivariate analysis revealed that age, education, current residential type, dating, sexual knowledge, attitudes, and pattern of communication were significantly associated with premarital sexual intercourse.</p> <p>Conclusion</p> <p>The unmarried migrant female workers lack sexual knowledge and a substantial proportion of them are engaged in premarital sexual behaviors. Interventions aimed at improving their sexual knowledge and related skills are needed.</p

Leptin and leptin receptor polymorphisms are associated with increased risk and poor prognosis of breast carcinoma

BACKGROUND: Leptin (LEP) has been consistently associated with angiogenesis and tumor growth. Leptin exerts its physiological action through its specific receptor (LEPR). We have investigated whether genetic variations in LEP and LEPR have implications for susceptibility to and prognosis in breast carcinoma. METHODS: We used the polymerase chain reaction and restriction enzyme digestion to characterize the variation of the LEP and LEPR genes in 308 unrelated Tunisian patients with breast carcinoma and 222 healthy control subjects. Associations of the clinicopathologic parameters and these genetic markers with the rates of the breast carcinoma-specific overall survival (OVS) and the disease free survival (DFS) were assessed using univariate and multivariate analyses. RESULTS: A significantly increased risk of breast carcinoma was associated with heterozygous LEP (-2548) GA (OR = 1.45; P = 0.04) and homozygous LEP (-2548) AA (OR = 3.17; P = 0.001) variants. A highly significant association was found between the heterozygous LEPR 223QR genotype (OR = 1.68; P = 0.007) or homozygous LEPR 223RR genotype (OR = 2.26; P = 0.001) and breast carcinoma. Moreover, the presence of the LEP (-2548) A allele showed a significant association with decreased disease-free survival in breast carcinoma patients, and the presence of the LEPR 223R allele showed a significant association with decreased overall survival. CONCLUSION: Our results indicated that the polymorphisms in LEP and LEPR genes are associated with increased breast cancer risk as well as disease progress, supporting our hypothesis for leptin involvement in cancer pathogenesis

Genetic association study of selected candidate genes (ApoB, LPL, Leptin) and telomere length in obese and hypertensive individuals

<p>Abstract</p> <p>Background</p> <p>A genetic study was carried out among obese and hypertensive individuals from India to assess allelic association, if any, at three candidate loci: Apolipoprotein B (ApoB) minisatellite and two tetranucleotide repeat loci; LPL (Lipoprotein lipase) and Leptin. Attempt has also been made to find out whether telomere length attrition is associated with hypertension and obese individuals.</p> <p>Methods</p> <p>Venous blood samples were collected from 37 normal, 35 obese and 47 hypertensive individuals. Genomic DNA was extracted from peripheral blood mononuclear cells (PBMC) and PCR amplifications were achieved using locus specific primers. Genotyping of ApoB minisatellite was performed using 4% polyacrylamide gel electrophoresis (PAGE) followed by silver staining, whereas LPL and Leptin loci were genotyped using ALF Express™ DNA sequencer. Telomere length was determined using a recently developed real time based quantitative PCR, where the relative telomere length was determined by calculating the relative ratio of telomere (T) and single copy gene (S) PCR products which is expressed as T/S ratio.</p> <p>Results</p> <p>All the three loci are highly polymorphic, display high heterozygosity and conform to Hardy-Weinberg's equilibrium expectations. ApoB minisatellite displayed 14 alleles, whereas LPL and Leptin tetranucleotide loci were having 9 and 17 alleles, respectively. Interestingly two new alleles (9 and 11 repeats) were detected at ApoB locus for the first time. The alleles at Leptin locus were classified as Class I (lower alleles: 149-200 bp) and Class II alleles (higher alleles: >217 bp). Higher alleles at ApoB (>39 repeats), predominant allele 9 at LPL and alleles 164 bp and 224 bp at Leptin loci have shown allelic association with hypertensive individuals. After adjusting the influence of age and gender, the analysis of co-variance (ANCOVA) revealed the relative telomere length (T/S ratio) in hypertensive individuals to be (1.01 ± 0.021), which was significantly different (P < 0.001) from obese (1.20 ± 0.023) and normal (1.22 ± 0.014) individuals. However, no significant difference in the relative telomere length was observed among male and female individuals, although age related decrease in telomere length was observed in these limited sample size.</p> <p>Conclusion</p> <p>The present study revealed that allelic association at ApoB, LPL, Leptin loci and loss of telomere length may have strong genetic association with hypertensive individuals. However, further study on larger sample size is needed to draw firm conclusions.</p