The use of vector-valued martingales in risk theory

A completely dependent risk process with perturbation and phase-type distributed claim sizes is analyzed. Claim arrivals are modeled by a Markovian arrival process. Using a vector-valued martingale, the Laplace transform of the time to ruin is derived algorithmically. The conditional memoryless property of the phase-type distribution yields the distribution of the deficit at ruin as a corollary.     

Novel Osmium‐based Coordination Complexes as Photosensitizers for Panchromatic Photodynamic Therapy

Cancer remains a major global malaise requiring the advent of new, efficient and low‐cost treatments. Photodynamic therapy, which combines a photosensitizer and photons to produce cytotoxic reactive oxygen species, has been established as an effective cancer treatment but has yet to become mainstream. One of the main limitations has been the paucity of photosensitizers that are effective over a wide range of wavelengths, can exert their cytotoxic effects in hypoxia, are easily synthesized and produce few if any side effects. To address these shortfalls, three new osmium‐based photosensitizers (TLD1822, TLD1824 and TLD1829) were synthesized and their photophysical and photobiological attributes determined. These photosensitizers are panchromatic (i.e. black absorbers), activatable from 200 to 900 nm and have strong resistance to photobleaching. In vitro studies show photodynamic therapy efficacy with both red and near‐infrared light in normoxic and hypoxic conditions, which translated to good in vivo efficacy of TLD1829 in a subcutaneous murine colon cancer model.     

A Facile Route to Metal Nitride Clusterfullerenes by Using Guanidinium Salts: A Selective Organic Solid as the Nitrogen Source

Using guanidinium salts 1 and 2 as the new nitrogen sources, metal nitride clusterfullerenes (NCFs) based on a variety of metals (Dy, Sc, Y, Gd, Lu, and mixed metals Sc/Dy, Sc/Gd, Sc/Lu, and Lu/Ce) have been synthesized based on a new “selective organic solid” (SOS) route. The synthesis of Dy‐NCFs by using Dy/ 1 was studied in detail, and the optimum molar ratio of 1 /Dy/C has been determined to be 2.5:1:10. For several representative metals such as Sc, Y, Gd, Dy, and Sc/Dy, we quantitatively compared the yield of M₃N@C₈₀ synthesized by the SOS route with the reported “reactive gas atmosphere” route, thereby indicating that the yield of M₃N@C₈₀ by using 1 could be comparable to that obtained by the reactive gas atmosphere route. Three other nitrogen sources ( 3 – 5 ) were also studied for comparison, which were mixed with Dy metal but did not result in the formation of Dy‐NCF. A possible reaction scheme for the solid‐state reaction of 1 , metal, and graphite is proposed. The SOS route appears to be a general route for the synthesis of NCFs that promises both high selectivity of NCFs and high reproducibility of the fullerene yield. Another advantages of the SOS route compared to the reported “trimetallic nitride template” (TNT) process and the reactive gas atmosphere route is that no additional heating pretreatment is needed, thus simplifying the procedure and being much more facile.