Polyureas were synthesized from diamines and carbon dioxide in the absence of any catalyst or solvent, analogous to the synthesis of urea from condensation of ammonia with carbon dioxide. The method used carbon dioxide as a carbonyl source to substitute highly toxic isocyanates for the synthesis of polyureas. FTIR and DFT calculations confirmed that strong bidentate hydrogen bonds were formed between urea motifs, and XRD patterns showed that the PUas were highly crystalline and formed a network structure through hydrogen bonds, which served as physical cross-links. The long chain PUas presented a microphase separated morphology as characterized by SAXS and showed a high melting temperature above 200 °C. The PUas showed high resistance to solvents and excellent thermal stability, which benefitted from their special network structures. The PUas synthesized by this method are a new kind of functional material and could serve some areas where their analogues with similar functional groups could not be applied.

Background Reproductive system cancer is an important cause of morbidity and mortality worldwide which threatens women's health and lives. Breast, cervical, and ovarian cancer have the higher incidence and mortality among a series of gynecology malignant tumor. We aimed to compare and assess the temporal trends of common female malignances on breast, cervical, and ovarian cancer mortality in developed regions of Asia including Japan, Republic of Korea, and Singapore and analyze the detached effects of chronological age, time period, and birth cohort by age-period-cohort (APC) analysis. Methods The mortality data for these three cancers were collected from the WHO Mortality Database in Japan, Republic of Korea, and Singapore from 1954 to 2013, from 1989 to 2013, and from 1964 to 2013, respectively. We fitted an age-period-cohort model and intrinsic estimator method to estimate the independent effect of each age, time period, and birth cohort on cancer mortality and describe the secular changes in three Asian countries. Results For the overall trends of breast cancer, the ASMRs of breast cancer showed a general increasing trend among three countries during the study periods while the change pattern in Singapore was different from the rest of the two countries for cervical and ovarian cancer. By APC analysis, the three cancer mortality risks generally increased with age and decreased with birth cohort. For period effects of breast and ovarian cancer, increasing effects with time were observed; however, for period effects of cervical cancer, converse change pattern was presented among three countries. Conclusions Our study shows that the ASMRs of breast, cervical, and ovarian cancer remain high in Singapore compared to Japan and Korea. Generally speaking, the mortality risk of three cancers increased with age, and period and cohort effects may collectively affect the common female malignances mortality for East Asian women.

Abstract:Background: As one of the most common cancers in the female population, cervical cancer has ranked as the second most incident gynecological cancer in recent years, trailing only breast cancer. We aimed to assess and compare the secular trends in cervical cancer mortality in China and the United States and analyze the independent effects of chronological age, time period and birth cohort using age-period-cohort (APC) analysis. Methods: We performed an age-period-cohort analysis using the intrinsic estimator method to estimate the independent effects of age, time period, and birth cohort on cervical cancer mortality. We collected mortality data for China and the United States from the WHO Mortality Database and China Health Statistical Yearbook database. Results: We examined the general trends in cervical mortality rates in China and the United States during the periods 1988-2012 and 1953-2012, respectively. The age-standardized mortality rates (ASMRs) for cervical cancer in urban China, rural China and the U.S. showed a general decreasing trend during the observation period, except for urban China, which experienced a significant increase beginning in 2002. The mortality rates for cervical cancer in the three areas showed a general increasing trend with age, regardless of the period effect. Period effects declined steadily in both rural China (from 0.19 to −0.26) and the U.S. (from −0.20 to −0.43); however, a slight increasing trend was identified (from −0.25 to 0.33) in urban China, which indicated that the risk of mortality increased with time. Cohort effects peaked in the cohort born in 1911-1915 in both rural China and urban China, declined consistently in the cohort born before 1950, and then decreased again in the cohort born after 1976-1980. The cohort effect in the U.S. peaked in the birth cohort born in 1876-1880, then leveled off and slightly decreased in younger generations. Conclusions: Our study showed that in general, cervical cancer mortality rates increased with age and decreased with birth cohort in the U.S., while the risk of mortality was highest in the cohort born during 1946-1975 in urban China. Additionally, the risk of mortality consistently increased with age in women younger than 64 years old in urban and rural China and began to decline in older groups. Although the age and cohort effects were relatively strong, the period effect may be the key factor affecting cervical cancer mortality trends, mainly reflecting the immediate effects of effective treatment and the implementation of screening.

To describe the temporal trends of breast cancer mortality in East Asia and to better understand the causes of these trends, we analyzed the independent effects of chronological age, time period and birth cohort on breast cancer mortality trends using age-period-cohort (APC) analysis. We chose three main countries in East Asia, namely China, South Korea, and Japan, which have reported death status to the WHO Mortality Database, and used the United States as a comparison population. Our study shows that in general, breast cancer mortality rates in females increased in all three East Asian countries throughout the study period. By APC analysis, we confirmed that there is, in fact, a difference in age-specific mortality rate patterns between the Eastern and the Western countries, which is presumably caused by the two-disease model. While the cause of the decrease from approximately the 1950s generation is still in question, we believe that increasing general awareness and improvements in the health-care system have made a significant contribution to it. Although the age and cohort effects are relatively strong, the period effect may be a more critical factor in the mortality trend, mainly reflecting the increase in exposures to carcinogens and behavioral risk factors.

Hydrogenation of nitrostyrene (NS) was studied with a Pt/TiO2 catalyst in CO2-dissolved ethanol and toluene phases at 323 K. The effects of CO2 pressure and organic solvents on the total conversion and the product distribution were examined. The conversion simply decreases with CO2 pressure in the both expanded solvents. The pressurization with CO2 varies the product selectivity in the nonpolar solvent but not in the polar solvent. The interactions among the substrate, solvent, and CO2 molecules were measured by in situ high-pressure FTIR methods in transmittance and attenuated total reflection modes. The reactivity of the nitro group of NS is lowered by interactions with CO2, which is responsible for the change in the product distribution. The local structures of an NS molecule in the expanded solvents are discussed from the results of FTIR and molecular dynamics simulations. The change in the product distribution is explained by the change of the local composition around the substrate molecule depending on CO2 pressure. The local composition is likely to change in the toluene but not in the ethanol, in accordance with the changes in the product selectivity in these two solvents. The substrate−CO2 interactions are important in toluene while those between the substrate and the solvent are predominant in ethanol even at high CO2 pressures.

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