Diffusion in higher dimensional SYK model with complex fermions

We construct a new higher dimensional SYK model with complex fermions on bipartite lattices. As an extension of the original zero-dimensional SYK model, we focus on the one-dimension case, and similar Hamiltonian can be obtained in higher dimensions. This model has a conserved U(1) fermion number Q and a conjugate chemical potential \mu. We evaluate the thermal and charge diffusion constants via large q expansion at low temperature limit. The results show that the diffusivity depends on the ratio of free Majorana fermions to Majorana fermions with SYK interactions. The transport properties and the butterfly velocity are accordingly calculated at low temperature. The specific heat and the thermal conductivity are proportional to the temperature. The electrical resistivity also has a linear temperature dependence term.Comment: 15 pages, 1 figure, add 4 references and fix some typos in this versio

Recent progress in the asymmetric Mannich reaction

The asymmetric Mannich reaction is one of the most useful carbon-carbon bond forming reactions for the synthesis of chiral molecules containing nitrogen. The resulting β-amino carbonyl compounds are valuable synthons in the preparation of many natural products with useful biological properties. In recent years, asymmetric Mannich processes have increasingly been reported and used in a rapidly growing number of applications. This review provides an overview of the recent history of the applications of various catalytic systems in asymmetric Mannich reaction, including metal-based asymmetric organocatalysis, asymmetric organocatalysis, other chiral catalysis and no chiral catalysis systems

Development and validation of an ELISA using a protein encoded by ORF2 antigenic domain of porcine circovirus type 2

<p>Abstract</p> <p>Background</p> <p>The capsid protein (ORF2) is a major structural protein of porcine circovirus type 2 (PCV2). A simple and reliable diagnostic method based on ORF2 protein immunoreactivity would serve as a valuable diagnostic method for detecting serum antibodies to PCV2 and monitoring PCV infection. Here, we reported an indirect enzyme-linked immunosorbent assay (I-ELISA) by using an antigenic domain (113-147AA) of ORF2-encoded antigen, expressed in <it>E. coli</it>, for diagnosis of PCV infection.</p> <p>Results</p> <p>The ELISA was performed on 288 serum samples collected from different porcine herds and compared with an indirect immunofluorescent assay (IFA). In total, 262 of 288 samples were positive as indicated by both I-ELISA and IFA. The specificity and sensitivity of I-ELISA were 87.7% and 93.57%.</p> <p>Conclusions</p> <p>This ELISA is suitable for detection and discrimination of PCV2 infection in both SPF and farm antisera.</p

Expression of telomerase inhibits hydroxyl radical-induced apoptosis in normal telomerase negative human lung fibroblasts

AbstractIn tumor cells telomerase activity is associated with resistance to apoptosis and the introduction of the human telomerase reverse transcriptase (hTERT) subunit into normal human cells is associated with life span extension of the cells. To determine the role of telomerase in regulating apoptosis, telomerase negative human embryo lung fibroblasts were transfected with the hTERT gene. Unlike the control fibroblasts, the telomerase-expressing cells had elongated telomeres and were resistant to apoptosis induced by hydroxyl radicals. The results indicate that expression of telomerase and, thus, the maintenance of telomere length in normal human somatic cells caused resistance to not only cellular senescence but also apoptosis. Moreover, we found that hydroxyl radical-induced apoptosis in telomerase-expressing and control fibroblasts was caspase-3 independent. These findings have revealed a new type of interrelation between telomerase and caspase-3, which may indicate that in this case the expressed telomerase may inhibit apoptosis at a site not related to the caspase-3 cascade

Identifying rodent olfactory bulb structures with micro-DTI

Conference Theme: Personalized Healthcare Through TechnologyOlfactory bulb (OB) is one of the most developed systems in rodent models with complex neuronal organization and anatomical structures. MR diffusion tensor imaging (DTI) is a non-invasive technique to probe tissue microstructures by examining the diffusion characteristics of water molecules. This paper presents how different OB layers can be identified and quantitatively characterized by micro-DTI using a specially constructed micro-imaging radio frequency (RF) coil. High spatial resolution and high signal to noise ratio (SNR) DTI images of ex vivo rat OBs were obtained. Distinct contrasts were observed between various olfactory bulb layers in trace map, fractional anisotropy (FA) map and FA color map, all in consistence with the known OB neuroanatomy. These experimental results demonstrate the utility of micro-DTI in investigation of complex OB organization. © 2008 IEEE.published_or_final_versio

Interferon-inducible ribonuclease ISG20 inhibits hepatitis B virus replication through directly binding to the epsilon stem-loop structure of viral RNA

Hepatitis B virus (HBV) replicates its DNA genome through reverse transcription of a viral RNA pregenome. We report herein that the interferon (IFN) stimulated exoribonuclease gene of 20 KD (ISG20) inhibits HBV replication through degradation of HBV RNA. ISG20 expression was observed at basal level and was highly upregulated upon IFN treatment in hepatocytes, and knock down of ISG20 resulted in elevation of HBV replication and attenuation of IFN-mediated antiviral effect. The sequence element conferring the susceptibility of HBV RNA to ISG20-mediated RNA degradation was mapped at the HBV RNA terminal redundant region containing epsilon (ε) stem-loop. Furthermore, ISG20-induced HBV RNA degradation relies on its ribonuclease activity, as the enzymatic inactive form ISG20D94G was unable to promote HBV RNA decay. Interestingly, ISG20D94G retained antiviral activity against HBV DNA replication by preventing pgRNA encapsidation, resulting from a consequence of ISG20-ε interaction. This interaction was further characterized by in vitro electrophoretic mobility shift assay (EMSA) and ISG20 was able to bind HBV ε directly in absence of any other cellular proteins, indicating a direct ε RNA binding capability of ISG20; however, cofactor(s) may be required for ISG20 to efficiently degrade ε. In addition, the lower stem portion of ε is the major ISG20 binding site, and the removal of 4 base pairs from the bottom portion of ε abrogated the sensitivity of HBV RNA to ISG20, suggesting that the specificity of ISG20-ε interaction relies on both RNA structure and sequence. Furthermore, the C-terminal Exonuclease III (ExoIII) domain of ISG20 was determined to be responsible for interacting with ε, as the deletion of ExoIII abolished in vitro ISG20-ε binding and intracellular HBV RNA degradation. Taken together, our study sheds light on the underlying mechanisms of IFN-mediated HBV inhibition and the antiviral mechanism of ISG20 in general

Serotonin-mediated modulation of Na+/K+ pump current in rat hippocampal CA1 pyramidal neurons

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to investigate whether serotonin (5-hydroxytryptamine, 5-HT) can modulate Na⁺/K⁺pump in rat hippocampal CA1 pyramidal neurons.</p> <p>Results</p> <p>5-HT (0.1, 1 mM) showed Na⁺/K⁺pump current (Ip) densities of 0.40 ± 0.04, 0.34 ± 0.03 pA/pF contrast to 0.63 ± 0.04 pA/pF of the control of 0.5 mM strophanthidin (Str), demonstrating 5-HT-induced inhibition of Ip in a dose-dependent manner in hippocampal CA1 pyramidal neurons. The effect was partly attenuated by ondasetron, a 5-HT₃receptor (5-HT₃R) antagonist, not by WAY100635, a 5-HT_1AR antagonist, while 1-(3-Chlorophenyl) biguanide hydrochloride (m-CPBG), a 5-HT₃R specific agonist, mimicked the effect of 5-HT on Ip.</p> <p>Conclusion</p> <p>5-HT inhibits neuronal Na⁺/K⁺pump activity via 5-HT₃R in rat hippocampal CA1 pyramidal neurons. This discloses novel mechanisms for the function of 5-HT in learning and memory, which may be a useful target to benefit these patients with cognitive disorder.</p