Regional climate modeling for Asia

The regional climate model (RCM) with higher resolution and sophisticated physical processes can reproduce and project fine-scale climate information, which cannot be captured by the global climate model (GCM). Therefore, we developed the Seoul National University Regional Climate Model (SNURCM) in the 1990s to simulate the intrinsic and detailed climate prevailing in Asia. In this study, we reviewed the developmental processes of the SNURCM and its application researches. In the simulation of regional climate over Asia, systematic errors can be generated because of natural characteristics such as complex land-surface conditions and topography, warm ocean conditions, and strong seasonal monsoon circulation and convection. Numerous methods and techniques have been applied to reduce these errors and improve the SNURCM. For long-term simulations without climate drift, the spectral nudging technique as well as the traditional relaxation method was employed for the boundary conditions. To represent reasonable interactions between earth systems, a simple ocean model and an advanced land-surface model were implemented into the SNURCM. Physical schemes for precipitation and vertical diffusion developed for short-term numerical weather prediction models were optimized or improved for long-term simulation. The SNURCM has been applied to future climate projection, reproduction of extreme climate, and seasonal forecasting. Furthermore, the model has served as a part of the multi-model comparison program and an ensemble of international research programs

Systematic review and meta-analysis: influence of smoking cessation on incidence of pneumonia in HIV.

BACKGROUND: Smoking is common in people infected with HIV but cessation support is not a routine part of clinical care. The aim was to assess whether smoking is a risk factor for pneumonia in people with HIV and whether smoking cessation ameliorates excess risk. METHODS: We performed MEDLINE and Embase database searches and included cohort or case-control studies conducted in adult patients infected with HIV extracting a hazard ratio (HR) or odds ratio (OR) that compared the incidence of bacterial pneumonia or pneumonia caused by Pneumocystis jiroveci (PCP) between two smoking categories. Studies were appraised for quality and combined using inverse variance meta-analysis. RESULTS: Fourteen cohort and case-control studies were included. Assessment of outcome was good, but assessment of exposure status was poor. Current smokers were at higher risk of bacterial pneumonia than former smokers: HR 1.37 (95% confidence interval (CI): 1.06, 1.78). There was no evidence that former smokers were at higher risk than never smokers: HR 1.24 (95%CI: 0.96, 1.60). Current smokers were at higher risk of bacterial pneumonia than current non-smokers: HR of 1.73 (95%CI: 1.44, 2.06). There was no evidence that smoking increased the incidence of PCP. The HR for current versus non-smokers was 0.94 (95%CI: 0.79, 1.12), but from case-control studies the OR was 1.76 (95%CI: 1.25, 2.48) with heterogeneity. Confined to higher quality studies, the OR was 0.97 (95%CI: 0.81, 1.16). Residual confounding is possible, but available data suggest this is not an adequate explanation. CONCLUSIONS: Smoking is a risk factor for bacterial pneumonia but not PCP and smoking cessation reduces this risk.See related article: http://www.biomedcentral.com/1741-7015/11/16.</p

Crucial role of Black Sea warming in amplifying the 2012 Krymsk precipitation extreme

Over the past 60 years, both average daily precipitation intensity and extreme precipitation have increased in many regions1, 2, 3. Part of these changes, or even individual events4, 5, have been attributed to anthropogenic warming6, 7. Over the Black Sea and Mediterranean region, the potential for extreme summertime convective precipitation has grown8 alongside substantial sea surface temperature increase. A particularly devastating convective event experienced in that region was the July 2012 precipitation extreme near the Black Sea town of Krymsk9. Here we study the effect of sea surface temperature (SST) increase on convective extremes within the region, taking the Krymsk event as a showcase example. We carry out ensemble sensitivity simulations with a convection-permitting atmospheric model and show the crucial role of SST increase in the extremeness of the event. The enhancement of lower tropospheric instability due to the current warmer Black Sea allows deep convection to be triggered, increasing simulated precipitation by more than 300% relative to simulations with SSTs characteristic of the early 1980s. A highly nonlinear precipitation response to incremental SST increase suggests that the Black Sea has exceeded a regional threshold for the intensification of convective extremes. The physical mechanism we identify indicates that Black Sea and Mediterranean coastal regions may face abrupt amplifications of convective precipitation under continued SST increase, and illustrates the limitations of thermodynamical bounds for estimating the temperature scaling of convective extremes

Bioactive glasses functionalized with polyphenols: in vitro interactions with healthy and cancerous osteoblast cells

Bioactive glasses are widely studied as biomaterials for bone contact applications. In this research work, the opportunity to modify the surface of a bioactive glass with polyphenols (gallic acid, and natural polyphenols extracted from red grape skin and green tea leaves) has been investigated in order to induce a selective anti-tumor activity in vitro. The presence of surface grafted molecules has been optically proved by fluorescence microscopy exploiting their autofluorescence. Direct and indirect cytotoxicity assays have been performed with human bone osteosarcoma cells (U2OS) and human fetal pre-osteoblasts (hFOB), as well as the quantification of oxygen and nitrogen reactive species (RONS) engendered from cells in response to the materials. Finally, the DNA damage of U2OS cells upon contact with the bioactive glass has been evaluated in order to verify any selective cytotoxic activity of functionalized materials against cancer cells. Results showed a selective cytotoxic activity of functionalized bioactive glasses toward osteosarcoma cells that was particularly evident when cells were cultivated directly onto glasses surface. Moreover, the presence of grafted polyphenols increased the RONS production and induced a permanent DNA damage on the U2SOS cells while they promote a certain anti-inflammatory action toward hFOB. These preliminary results suggest polyphenols grafted bioactive glasses as promising material for bone substitution in cancer treatment