Organizational Modes of Severe Wind-producing Convective Systems over North China

Severe weather reports and composite radar reflectivity data from 2010–14 over North China were used to analyze the distribution of severe convective wind(SCW) events and their organizational modes of radar reflectivity. The six organizational modes for SCW events(and their proportions) were cluster cells(35.4%), squall lines(18.4%), nonlinear-shaped systems(17.8%), broken lines(11.6%), individual cells(1.2%), and bow echoes(0.5%). The peak month for both squall lines and broken lines was June, whereas it was July for the other four modes. The highest numbers of SCW events were over the mountains, which were generally associated with disorganized systems of cluster cells. In contrast, SCW associated with linear systems occurred mainly over the plains, where stations recorded an average of less than one SCW event per year. Regions with a high frequency of SCW associated with nonlinear-shaped systems also experienced many SCW events associated with squall lines. Values of convective available potential energy, precipitable water, 0–3-km shear, and 0–6-km shear, were demonstrably larger over the plains than over the mountains, which had an evident effect on the organizational modes of SCW events. Therefore, topography may be an important factor in the organizational modes for SCW events over North China.

A review of UHMWPE wear-induced osteolysis:the role for early detection of the immune response

In a world where increasing joint arthroplasties are being performed on increasingly younger patients,osteolysis as the leading cause of failure after total joint arthroplasty(TJA) has gained considerable attention.Ultra-high molecular weight polyethylene wear-induced osteolysis is the process by which prosthetic debris mechanically released from the surface of prosthetic joints induces an immune response that favors bone catabolism, resulting in loosening of prostheses with eventual failure or fracture. The immune response initiated is innate in that it is nonspecific and self-propagating, with monocytic cells and osteoclasts being the main effectors. To date, detecting disease early enough to implement effective intervention without unwanted systemic side effects has been a major barrier. These barriers can be overcome using newer in vivo imaging techniques and modules linked with fluorescence and/or chemotherapies. We discuss the pathogenesis of osteolysis, and provide discussion of the challenges with imaging and therapeutics. We describe a positron emission tomography imaging cinnamoyl-Phe-(D)-Leu-Phe-(D)-Leu-Phe-Lys module,specific to macrophages, which holds promise in early detection of disease and localization of treatment.Further research and increased collaboration among therapeutic and three-dimensional imaging researchers are essential in realizing a solution to clinical osteolysis in TJA.

Relationships between Cloud Droplet Spectral Relative Dispersion and Entrainment Rate and Their Impacting Factors

Cloud microphysical properties are significantly affected by entrainment and mixing processes.However,it is unclear how the entrainment rate affects the relative dispersion of cloud droplet size distribution.Previously,the relationship between relative dispersion and entrainment rate was found to be positive or negative.To reconcile the contrasting relationships,the Explicit Mixing Parcel Model is used to determine the underlying mechanisms.When evaporation is dominated by small droplets,and the entrained environmental air is further saturated during mixing,the relationship is negative.However,when the evaporation of big droplets is dominant,the relationship is positive.Whether or not the cloud condensation nuclei are considered in the entrained environmental air is a key factor as condensation on the entrained condensation nuclei is the main source of small droplets.However,if cloud condensation nuclei are not entrained,the relationship is positive.If cloud condensation nuclei are entrained,the relationship is dependent on many other factors.High values of vertical velocity,relative humidity of environmental air,and liquid water content,and low values of droplet number concentration,are more likely to cause the negative relationship since new saturation is easier to achieve by evaporation of small droplets.Further,the signs of the relationship are not strongly affected by the turbulence dissipation rate,but the higher dissipation rate causes the positive relationship to be more significant for a larger entrainment rate.A conceptual model is proposed to reconcile the contrasting relationships.This work enhances the understanding of relative dispersion and lays a foundation for the quantification of entrainment-mixing mechanisms.

Progress in Severe Convective Weather Forecasting in China since the 1950s

Located in the Asian monsoon region, China frequently experiences severe convective weather(SCW), such as short-duration heavy rainfall(SDHR), thunderstorm high winds, hails, and occasional tornadoes. Progress in SCW forecasting in China is closely related to the construction and development of meteorological observation networks,especially weather radar and meteorological satellite networks. In the late 1950 s, some county-level meteorological bureaus began to conduct empirical hail forecasting based on observations of clouds and surface meteorological variables. It took over half a century to develop a modern comprehensive operational monitoring and warning system for SCW forecast nationwide since the setup of the first weather radar in 1959. The operational SCW forecasting, including real-time monitoring, warnings valid for tens of minutes, watches valid for several hours, and outlooks covering lead times of up to three days, was established in 2009. Operational monitoring and forecasting of thunderstorms,SDHR, thunderstorm high winds, and hails have been carried out. The performance of operational SCW forecasting will be continually improved in the future with the development of convection-resolving numerical models(CRNMs), the upgrade of weather radar networks, the launch of new-generation meteorological satellites, better understanding of meso-γ and microscale SCW systems, and further application of artificial intelligence technology and CRNM predictions.

Preparation of P(MBA-co-MAA)/Zr(OH)_(4)/P(EGDMA-co-MAA)/TiO_(2)Tetra-layer Hybrid Microspheres and the Corresponding ZrO_(2)/TiO_(2)Double-shelled Hollow Microspheres

Double-shelled zirconia/titania(ZrO_(2)/TiO_(2))hollow microspheres were prepared by the selective removal of the polymer components via the calcination of the corresponding tetra-layer poly(N,N'-methylenebisacryl amide-comethacrylic acid)(P(MBA-co-MAA))/Zr(OH)_(4)/poly(ethyleneglycol dimethacrylate-co-methacrylic acid)(P(EGDMAco-MAA))/TiO_(2)hybrid microspheres.These tetra-layer microspheres were synthesized by the combination of the distillation copolymerization of N,N′-methylenebisacryl amide-co-methacrylic acid(MBA)or ethyleneglycol dimethacrylate(EGDMA)crosslinker and methacrylic acid(MAA)for the preparation of polymer core and thirdlayer as well as the controlled sol-gel hydrolysis of inorganic precursors for the construction of zirconium hydroxide(Zr(OH)_(4))and titania(TiO_(2))layers.The thicknesses of zirconia and titania shell-layers were conveniently controlled via varying the feed of zirconium n-butoxide(Zr(OBu)_(4))and titanium tetrabutoxide(TBOT)during the sol-gel hydrolysis,while the sizes of polymer layers were tuned through a multi-stage distillation precipitation copolymerization.The structure and morphology of the resultant microspheres were characterized by transmission electron microscopy(TEM),X-ray diffractometer(XRD),X-ray photoelectronic spectroscopy(XPS),and thermogrametric analysis(TGA).