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[1] An intercomparison study involving eight dust emission/transport models over Asia (DMIP) has been completed. Participating dust models utilize a variety of dust emission schemes, horizontal and vertical resolutions, numerical methods, and different meteorological models. Two huge dust episodes occurred in spring 2002 and were used for the DMIP study. Meteorological parameters, dust emission flux and dust concentration (diameter < 20 mm) are compared within the same domain on the basis of PM and NIES lidar measurements. We found that modeled dust concentrations between the 25% and 75% percentiles generally agreed with the PM observations. The model results correctly captured the major dust onset and cessation timing at each observation site. However, the maximum concentration of each model was 2-4 times different. Dust emission fluxes from the Taklimakan Desert and Mongolia differ immensely among the models, indicating that the dust source allocation scheme over these regions differs greatly among the various modeling groups. This suggests the measurements of dust flux and accurate updated land use information are important to improve the models over these regions. The dust vertical concentration profile at Beijing, China, and Nagasaki, Japan, has a large scatter (more than two times different) among the models. For Beijing, the scaled dust profile has a quite similar vertical profile and shows relatively good agreement with the lidar extinction profile. However, for Nagasaki, the scaled dust profiles do not agree. These results indicate that modeling of dust transport and removal processes between China and Japan is another important issue in improving dust modeling.

Periodontal ligament (PDL) cells play an important role in maintaining the homeostasis of periodontal tissues. However, it is not known how PDL cells contribute to osteoclastogenesis. In this study, we examined the consequences of cell-to-cell interactions between peripheral blood mononuclear cells (PBMCs) and PDL cells during osteoclastogenesis. PBMCs were co-cultured directly or indirectly with PDL cells for two to four weeks. PBMCs that were directly co-cultured with PDL cells formed significantly more resorption pits on dentin slices than did PBMCs that were cultured alone. However, soluble factor(s) produced from PDL cells inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. Furthermore, PDL cells expressed both receptor activator nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) mRNA. In conclusion, PDL cells support osteoclastogenesis through cell-to-cell contact. PDL cells might regulate osteoclastogenesis by opposing mechanisms--stimulation of resorptive activity by RANKL and inhibition by OPG--thus affecting processes such as periodontitis and orthodontic tooth movement.

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To investigate the effects of the middle atmosphere on climate, the World Climate Research Programme is supporting the project "Stratospheric Processes and their Role in Climate" (SPARC). A central theme of SPARC, to examine model simulations of the coupled troposphere-middle atmosphere system, is being performed through the initiative called GRIPS (GCM-Reality Intercomparison Project for SPARC). In this paper, an overview of the objectives of GRIPS is given. Initial activities include an assessment of the performance of middle atmosphere climate models, and preliminary results from this evaluation are presented here. It is shown that although all 13 models evaluated represent most major features of the mean atmospheric state, there are deficiencies in the magnitude and location of the features, which cannot easily be traced to the formulation (resolution or the parameterizations included) of the models. Most models show a cold bias in all locations, apart from the tropical tropopause region where they can be either too warm or too cold. The strengths and locations of the major jets are often misrepresented in the models. Looking at three-dimensional fields reveals, for some models, more severe deficiencies in the magnitude and positioning of the dominant structures (such as the Aleutian high in the stratosphere), although undersampling might explain some of these differences from observations. All the models have shortcomings in their simulations of the present-day climate, which might limit the accuracy of predictions of the climate response to ozone change and other anomalous forcing.

A new method of nesting a high-resolution limited area model (LAM) in a low-resolution global model (GCM) is proposed for the purpose of conducting.regional climate simulations. It is tested with a few feasibility studies of month-long time integrations of the LAM.The conventional method of embedding a LAM in a larger area model is to couple the inner to the outer model in terms of lateral boundary conditions in real space. In the present method, the concept of a spectral boundary in wavenumber space is the key to joining a high-resolution LAM to a low-resolution GCM.In practice the new technique of combining the two different resolution models is to replace the large-scale fields of the LAM with the corresponding large-scale fields supplied externally from the GCM at a selected regular time interval.The present experiments showed that the time integration was very smooth over a period of one month, and that the mesoscale features associated with the large-scale supplied from the GCM were well simulated, suggesting that the new method is encouraging for regional mesoscale climate simulations.