System-size independence of directed flow measured at the BNL relativistic heavy-ion collider

We measure directed flow (v_{1}) for charged particles in Au+Au and Cu+Cu collisions at sqrt[s_{NN}]=200 and 62.4 GeV, as a function of pseudorapidity (eta), transverse momentum (p_{t}), and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragmentation concept to v_{1} in different collision systems, and investigate possible explanations for the observed sign change in v_{1}(p_{t}).

Self-assembling peptide nanofiber as potential substrates in islet transplantation

Hypoxia and reoxygenation (H/R)-induced damage often happens soon after islets are transplantation. The process of islet isolation and purification causes the rapid onset of hypoxia. We sought to develop a functional scaffold to sustain the structure and function of islets as well as to recover some of the surface molecules damaged during isolation, seeking to improve islet transplantation outcomes. Self-assembling peptide nanofiber (SAPNF), a new type of substrate has been shown to be an excellent biological material for neuronal cell culture and tissue engineering in animals. In this study, we investigated the protective effect of SAPNF on damage to rat islets. Freshly prepared rat islets from male Sprague-Dawley rats were seeded in plates coated with (SAPNF-treated group) or without (control group) SAPNF. The islets were then divided into two groups culture under normoxia for 7 days versus exposure to hypoxia (< 1% O2) for 6 hours followed by reoxygenation for 24 hours. The results showed that SAPNF exhibited improving effects on viability and function of cultured islets, protecting the one from H/R-induced damage. In both groups, the stimulation index of SAPNF-treated groups were about two times the controls. SAPNF treatment decreased apoptotic rates of islet cells. These results suggested the usefulness of SAPNF to maintain the viability and function of rat pancreatic islets. SAPNF may be a potential scaffold for clinical islet transplantation.

Cloning, sequencing, and analysis of the full-length CDNA of rhesus monkey factor IX

OBJECTIVE

Coagulation factor IX (FIX) is a vitamin K-dependent serine protease, which plays a key role in the coagulation cascade. The rhesus monkey may be an indispensable substitute for humans in research of pig-to-human xenotransplantation, due to its close relationship. But the coagulation function concordance between rhesus monkey and human is unknown. In this study, we cloned the full-length cDNA of rhesus monkey FIX (rFIX) to investigate the genomic backgrounds of the coagulation systems.

METHOD

We cloned the full-length cDNA from the cDNA library of rhesus monkey liver tissue. Polymerase chain reaction was used to screen the positive clones. Based on a partial sequence obtained by cDNA library screening and a homologous sequence from the database, we designed a second pair of primers to obtain the full sequence. For further analysis of rFIX, we used several online ExPASy Proteomic tools.

RESULT

We obtained the full-length cDNA of rFIX, which has 2668 nucleotides, predicting an open reading frame of 1383 nucleotides corresponding to 461 amino acids. The deduced protein sequence indicated functional domains of signal peptide, Gla, two epidermal growth factor, and trypsin-like serine protease, which were consisted with those of human FIX (hFIX). Sequence alignments showed that rFIX is highly homologous to hFIX with nucleotide identity of 96% and amino acid identity of 97%.

CONCLUSION

We have report herein the full-length cDNA of rFIX. The high homology between rhesus monkey and human coagulation factor ensure the reliability and feasibility of rhesus monkey as a recipient in studies on coagulation disorders in xenotransplantation.

Forward neutral-pion transverse single-spin asymmetries in p + p collisions at sqrt[s] = 200 GeV

We report precision measurements of the Feynman x (xF) dependence, and first measurements of the transverse momentum (pT) dependence, of transverse single-spin asymmetries for the production of pi0 mesons from polarized proton collisions at sqrt[s] = 200 GeV. The xF dependence of the results is in fair agreement with perturbative QCD model calculations that identify orbital motion of quarks and gluons within the proton as the origin of the spin effects. Results for the pT dependence at fixed xF are not consistent with these same perturbative QCD-based calculations.

Insulin-like growth factor-1 receptor polymorphism and ischemic stroke: a case-control study in Chinese population

OBJECTIVES

Low levels of insulin-like growth factor 1 (IGF-1) are associated with atherosclerosis, and insulin-like growth factor-1 receptor (IGF-1R) polymorphisms can change plasma levels of IGF-1 and may alter the function of the receptor. Whether there is any association of genetic variation in IGF-1R gene with ischemic stroke (IS) is presently unknown.

MATERIALS AND METHOD

A 1:1 case-control study was conducted. The G --> A polymorphism of IGF-1R gene (rs2229765) were analyzed by TaqMan SNP genotyping technique in Chinese patients with IS (n = 309) and old subjects without IS (n = 309).

RESULTS

The frequency of A allele in the patients and controls was 45.79% and 39.64%, respectively. The AA genotype distribution of IGF-1R gene was significantly higher in the patients (27.51%) than controls (18.23%; P = 0.022). Conditional logistic regression revealed that the AA genotype of IGF-1R was associated with IS (OR = 1.641, P = 0.022). After adjustment for smoking, alcohol drinking, history of hypertension, and body mass index, IGF-1R AA genotype was still significantly associated with an increased risk of IS (OR = 1.787, P = 0.029), compared with IGF-1R GG.

CONCLUSIONS

The G --> A polymorphism in IGF-1R gene may affect the susceptibility to IS in Chinese population.

Association between metabolic gene polymorphisms and susceptibility to peripheral nerve damage in workers exposed ton-hexane: A preliminary study

Chronic exposure to n-hexane may result in peripheral neuropathy. 2,5-Hexanedione (2,5-HD) has been identified as a toxic metabolite of n-hexane. The CYP2E1, CYP1A1 and GST genes are involved in the formation of 2,5-hexanedione from n-hexane as well as the elimination of 2,5-HD-formed electrophile, and these genes are highly polymorphic in the general population. A nested case-control study in an industrial cohort was conducted to evaluate the associations between polymorphisms in these metabolic genes and n-hexane-induced peripheral nerve damage. The study subjects included 22 cases, who worked in a printing factory with symptoms of peripheral nerve damage, and 163 controls, who came from the same factory of cases. DNA was extracted from blood samples and genotyping was conducted for CYP2E1 Pst, CYP2E1 Dra, CYP2E1 Ins96, CYP1A1 Msp, GSTT1 null, GSTM1 null and GSTP1 105V. Unconditional logistic regression was applied to estimate the odds ratio and 95% confidence intervals. There were no significant differences between the two groups regarding age, sex, smoking and alcohol status. A significant association between Dra polymorphism and peripheral nerve damage was found. The frequency of CYP2E1 Dra homozygous mutation in the case group (18.2%) was higher than that in the control group (3.7%, p=0.015). Individuals with homozygote genotype (CC) of CYP2E1 Dra had a significantly higher risk of peripheral nerve damage compared with those with DD genotype (adjusted OR=?.58, 95% CI=1.32-23.65) after n-hexane exposure duration, sex, age, smoking and alcohol status were adjusted. No significant association was found that CYP2E1 Pst, CYP2E1 Ins96, CYP1A1 Msp, GSTT1, GSTM1, GSTP gene polymorphisms associated with the susceptibility of peripheral nerve damage. These findings suggested that CYP2E1 gene might increase the susceptibility to n-hexane-induced peripheral damage.

Association between nucleotide excision repair gene polymorphisms and chromosomal damage in coke-oven workers

The associations between several genetic polymorphisms of nucleotide excision repair genes (NER) and chromosome damage level were studied among 140 coke-oven workers exposed to a high level of polyaromatic hydrocarbons (PAHs) and 66 non-exposed workers. Seven polymorphisms with functional potential in five NER genes (ERCC1, ERCC2, ERCC4, ERCC5 and ERCC6) were genotyped in the 206 study subjects. Multivariate analysis of covariance revealed that coke-oven workers with the ERCC1 19007 CC genotype had significantly higher cytokinesis-block micronucleus frequency (CBMN) (10.5 +/- 6.8 per thousand) than those with CT (8.1 +/- 6.6 per thousand, p = 0.01) or TT (6.6 +/- 3.7-/ per thousand p = 0.05) or CT+TT genotypes (7.5 +/- 6.3 per thousand, p = 0.004). The ERCC6 A3368G polymorphism was also associated with CBMN frequency among coke-oven workers. Subjects with the AA genotype have a significantly higher CBMN frequency (10.0 +/- 6.9 per thousand) than those with AG (6.7 +/- 4.2 per thousand, p = 0.05) or AG+GG genotypes (6.6 +/- 4.1 per thousand, p = 0.02). Stratification analysis revealed the significant associations between ERCC1 C19007T and ERCC6 A3368G, and the CBMN frequencies were only found among older workers. In addition, a significant association between ERCC2 G23591A polymorphism and CBMN frequencies was also found among older coke-oven workers. The results suggest that polymorphisms of ERCC1 C19007T, ERCC6 A3368G and ERCC2 G23591A are associated with the CBMN frequencies among coke-oven workers.

Quantum noise in the collective abstraction reaction A + B2-->AB + B

We demonstrate theoretically that the collective abstraction reaction A + B2-->AB + B can be realized efficiently with degenerate bosonic or fermionic matter waves. We show that this is dominated by quantum fluctuations, which are critical in triggering its initial stages with the appearance of macroscopic nonclassical correlations of the atomic and molecular fields as a result. This study opens up a promising new regime of quantum-degenerate matter-wave chemistry.