Sphingosine 1-phosphate-metabolizing enzymes control influenze virus amplification and the viral cyto-pathogenicity [abstract]

Sphingosine 1-phosphate (S1P) is regulated by cellular catalytic enzymes and has diverse biological functions. However, the effects that S1P-catalyzing enzymes have on host defense and immunity to invading viruses remain unknown. In this study, we investigated the role of S1P-metabolyzing enzymes in modulating cellular responses to influenza virus infection. Over- expression of S1P lyase (SPL), which induces degradation of S1P on cells (SPL-cells), interfered with the propagation of influenza virus. Accordingly, SPL-cells were much more resistant to the cytopathic effects caused by influenza virus infection than the control cells. SPL-mediated inhibition of cellular death was supported by impairment of the upregulation of a pro-apoptotic protein Bax, a critical factor for influenza viral cyto-pathogenicity. Importantly, the virus-infected SPL-cells induced early activation of STAT1 and STAT2 that are representative proteins for the anti-viral type I IFN signaling. These results suggest that SPL suppresses influenza virus replication via rapid activation of host innate immunity. In contrast to the SPL, the over-expression of S1P-producing sphingosine kinase 1 heightened the cells' susceptibility to influenza viral infection with suppressed STAT1 activation, representing opposed enzymatic activity. These findings suggest that the modulation of S1P-metabolyzing enzymes is crucial for controlling host innate immunity and resultant host defense against influenza viral infection. Thus, S1P-metabolizing enzymes are novel potential targets to treat diseases caused by influenza virus infection

Thermoelectric Conductivities at Finite Magnetic Field and the Nernst Effect

We study the thermoelectric conductivities of a strongly correlated system in the presence of a magnetic field by the gauge/gravity duality. We consider a class of Einstein-Maxwell-Dilaton theories with axion fields imposing momentum relaxation. General analytic formulas for the direct current(DC) conductivities and the Nernst signal are derived in terms of the black hole horizon data. For an explicit model study, we analyse in detail the dyonic black hole modified by momentum relaxation. In this model, for small momentum relaxation, the Nernst signal shows a bell-shaped dependence on the magnetic field, which is a feature of the normal phase of cuprates. We compute all alternating current(AC) electric, thermoelectric, and thermal conductivities by numerical analysis and confirm that their zero frequency limits precisely reproduce our analytic DC formulas, which is a non-trivial consistency check of our methods. We discuss the momentum relaxation effects on the conductivities including cyclotron resonance poles.Comment: v3: Minor chages, discussions clarified, version accepted in JHE

Gauge Invariance and Holographic Renormalization

We study the gauge invariance of physical observables in holographic theories under the local diffeomorphism. We find that gauge invariance is intimately related to the holographic renormalisation: the local counter terms defined in the boundary cancel most of gauge dependences of the on-shell action as well as the divergences. There is a mismatch in the degrees of freedom between the bulk theory and the boundary one. We resolve this problem by noticing that there is a residual gauge symmetry(RGS). By extending the RGS such that it satisfies infalling boundary condition at the horizon, we can understand the problem in the context of general holographic embedding of a global symmetry at the boundary into the local gauge symmetry in the bulk.Comment: 14 pages, v2: minor changes, typos corrected, references adde

Character of Matter in Holography: Spin-Orbit Interaction

Gauge/Gravity duality as a theory of matter needs a systematic way to characterise a system. We suggest a `dimensional lifting' of the least irrelevant interaction to the bulk theory. As an example, we consider the spin-orbit interaction, which causes magneto-electric interaction term. We show that its lifting is an axionic coupling. We present an exact and analytic solution describing diamagnetic response. Experimental data on annealed graphite shows a remarkable similarity to our theoretical result. We also find an analytic formulas of DC transport coefficients, according to which, the anomalous Hall coefficient interpolates between the coherent metallic regime with $\rho_{xx}^{2}$ and incoherent metallic regime with $\rho_{xx}$ as we increase the disorder parameter $\beta$. The strength of the spin-orbit interaction also interpolates between the two scaling regimes.Comment: 15pages, 3 figure

Coherent/incoherent metal transition in a holographic model

We study AC electric($\sigma$), thermoelectric($\alpha$), and thermal($\bar{\kappa}$) conductivities in a holographic model, which is based on 3+1 dimensional Einstein-Maxwell-scalar action. There is momentum relaxation due to massless scalar fields linear to spatial coordinate. The model has three field theory parameters: temperature($T$), chemical potential($\mu$), and effective impurity($\beta$). At low frequencies, if $\beta < \mu$, all three AC conductivities($\sigma, \alpha, \bar{\kappa}$) exhibit a Drude peak modified by pair creation contribution(coherent metal). The parameters of this modified Drude peak are obtained analytically. In particular, if $\beta \ll \mu$ the relaxation time of electric conductivity approaches to $2\sqrt{3} \mu/\beta^2$ and the modified Drude peak becomes a standard Drude peak. If $\beta > \mu$ the shape of peak deviates from the Drude form(incoherent metal). At intermediate frequencies($T<\omega<\mu$), we have analysed numerical data of three conductivities($\sigma, \alpha, \bar{\kappa}$) for a wide variety of parameters, searching for scaling laws, which are expected from either experimental results on cuprates superconductors or some holographic models. In the model we study, we find no clear signs of scaling behaviour.Comment: 27 pages, 9 figures, v2,v3: minor changes, typos corrected, reference adde

The role of seaports in regional employment: evidence from South Korea

<p>The role of seaports in regional employment: evidence from South Korea. <i>Regional Studies</i>. This study examines the seaport’s influence on regional employment in all 16 regions of Korea, including seven metropolitan areas, based on panel data between 2002 and 2013. It expands an economic model of regional unemployment from labour economics and an autoregressive model from econometrics by employing port potentials separately estimated in a Tobit model. The result indicates that port activities significantly reduce regional unemployment rates relative to the national level. The role of population, gross domestic product (GDP) and household income on unemployment rate was highlighted, whilst various determinants of port potentials were investigated about whether they stimulate port potentials.</p

Risk factors of Metabolic Syndrome and Lifestyle in Early Adulthood in Korea

The objective of this study was to identify risk factors of metabolic syndrome in early adulthood which has currently shown an increase in Korea, due to a westernized lifestyle. Health medical examination data collected from a total of 5801 participants, gathered by the National Health Insurance Service(NHIS) in 2013, was used to proceed with the study. NCEP ATP-III was used as diagnostic criteria for determining metabolic syndrome. The prevalence rate for metabolic syndrome totaled 32.8%, 29.7% for men and 3.1% for women. Among the subjects, 21.5% of men were found to have abnormal waist circumferences compared to a percentage of 2.3% for women. However, the HDL-cholesterol levels for both men and women were very similar, at 13.6% and 13.3% respectively. There were statistically significant differences in their BMIs, family histories of diabetes, smoking periods, smoking frequencies, alcohol consumption, drinking frequencies, and intense physical activities for the metabolic syndrome group and the normal group. The factors influencing metabolic syndrome were BMI(OR=1.645, 95% CI, 1.599-1.692), a high risk of diabetes(OR=8.818, 95% CI, 4.493-17.306), drinking frequency(OR=1.151, 95% CI, 1.074-1.233), smoking period(OR=1.037, 95% CI, 1.010-1.064), whereas the family history of diabetes, smoking frequency, and physical activity showed no significance. The factors attributing to a high risk in diabetes were BMI(OR=1.021, 95% CI, 1.008-1.035), family history of diabetes(OR=1.835, 95% CI, 1.045-3.225), smoking period(OR=1.125, 95% CI, 1.050-1.206), presence of metabolic syndrome(OR=8.519, 95% CI, 4.876-14.885). The result from the data illustrates the necessity in developing programs and management education for such factors (BMI, smoking, drinking) that influence metabolic syndrome in early adulthood. Promotion of the environment and social awareness of metabolic syndrome is also required to make possible improvements in lifestyle

Increased Risk of Ischemic Stroke during Sleep in Apneic Patients.

BACKGROUND AND PURPOSE:The literature indicates that obstructive sleep apnea (OSA) increases the risk of ischemic stroke. However, the causal relationship between OSA and ischemic stroke is not well established. This study examined whether preexisting OSA symptoms affect the onset of acute ischemic stroke. METHODS:We investigated consecutive patients who were admitted with acute ischemic stroke, using a standardized protocol including the Berlin Questionnaire on symptoms of OSA prior to stroke. The collected stroke data included the time of the stroke onset, risk factors, and etiologic subtypes. The association between preceding OSA symptoms and wake-up stroke (WUS) was assessed using multivariate logistic regression analysis. RESULTS:We identified 260 subjects with acute ischemic strokes with a definite onset time, of which 25.8% were WUS. The presence of preexisting witnessed or self-recognized sleep apnea was the only risk factor for WUS (adjusted odds ratio=2.055, 95% confidence interval=1.035-4.083, p=0.040). CONCLUSIONS:Preexisting symptoms suggestive of OSA were associated with the occurrence of WUS. This suggests that OSA contributes to ischemic stroke not only as a predisposing risk factor but also as a triggering factor. Treating OSA might therefore be beneficial in preventing stroke, particularly that occurring during sleep

Sex/Gender Differences in Work and Pathways to Parenthood in Industrialized Economies

Ph.D