No abstract

The integration of synergic hydrogen bond donors and nucleophilic anions that facilitates the ring-opening of epoxide is an effective way to develop an active catalyst for the cycloaddition of CO2 with epoxides. In this work, a new heterogeneous catalyst for the cycloaddition of epoxides and CO2 into cyclic carbonates based on dual hydroxyls-functionalized polymeric phosphonium bromide (PQPBr-2OH) was presented. Physicochemical characterizations suggested that PQPBr-2OH possessed large surface area, hierarchical pore structure, functional hydroxyl groups, and high density of active sites. Consequently, it behaved as an efficient, recyclable, and metal-free catalyst for the additive and solvent free cycloaddition of epoxides with CO2. Comparing the activity of PQPBr-2OH with that of the reference catalysts based on mono and non-hydroxyl functionalized polymeric phosphonium bromides suggested that hydroxyl functionalities in PQPBr-2OH showed a critical promotion effect on its catalytic activity for CO2 conversion. Moreover, PQPBr-2OH proved to be quite robust and recyclable. It could be reused at least ten times with only a slight decrease of its initial activity.

Developing highly active catalysts with the combined advantages of molecular and solid catalysis is considered as the “Holy Grail” in the area of catalysis research. Herein, a phosphorus‐doped porous polymer‐immobilized palladium was successfully developed as an efficient, robust, and recyclable catalyst for the carbonylative Suzuki coupling and alkoxycarbonylation reactions of aryl halides. Rather than just as an immobilizing molecular catalyst, palladium supported on phosphorus‐doped porous organic polymer exhibits even better catalytic performances than that of its analogue homogeneous catalysts in both carbonylation reactions. Moreover, the catalyst can be easily separated and reused for at least 5 times without significant loss in reactivity. Importantly, the catalyst was highly stable under carbonylation reaction conditions, and no palladium nanoparticle was observed even after the 5th reuse.

The epidemic caused by the novel coronavirus COVID-19 in Wuhan at the end of 2019 has become an urgent public event of worldwide concern. However, due to the changing data of the epidemic, there is no scientific estimate of the cure rate and case fatality rate of the epidemic. This study proposes a method to estimate the cure rate and case fatality rate of COVID-19. The ratio of cumulative discharges on a given day to the sum of cumulative discharges on a given day and cumulative deaths before j days is used to estimate the cure rate.Moreover, the case fatality ratio can also be estimated. After simulation calculations, j is statistically appropriate when it is 8-10, and it is also clinically appropriate. When j is 9, based on the available data, it is inferred that the cure rate of this epidemic is about 93% and the case fatality rate is about 7%. This method of estimating the cure rate can be used to evaluate the effectiveness of treatment in different medical schemes and different regions, and has great value and significance for decision-making in the epidemic.

Human beings are constantly struggling with various epidemics. Although we gained a lot of experience and success, in the face of the new epidemic, we still inevitably face pressure from public health, politics, and the economy. Case fatality ratio (CFR) received widespread attention as one of the indicators describing the severity of the epidemic and evaluating treatment options. However, due to the ongoing epidemic situation and the constant changes in the death and diagnosis data, no scientific method for this situation to calculate the CFR exists. This study proposes a method for estimating CFR in the continuation of the epidemic. CFR is estimated by "ratio of the cumulative number of deaths before j days from a given day to the sum of the number of patients discharged from a given day and the cumulative number of deaths before j days from a given day ". Take the ongoing outbreak of COVID COVID-19 in December 2019 as an example. The results show that, regardless of the size of the estimated value or its changing trend, the estimated CFR given by the new method shows better stability and better reflects the true situation of the case fatality rate; additionally, the improvement of medical conditions can also be clearly reflected in the change in valuation. When j = 10, according to the data of March 10, the CFR of COVIDCOVID-19 in Wuhan, China and China (excluding Hubei)is 6.23%,4.46%, and 0.87%, respectively. This method of estimating CFR can be used in time to evaluate the therapeutic effect of different medical schemes and different regions, which is of great value and significance for the decision decision-making in the epidemicprevention and control.Authors Wanling Hu, Xiaoyun Liu, and Tao Wang contributed equally to this work

The epidemic caused by the novel coronavirus in Wuhan at the end of 2019 has become an urgent public event of worldwide concern. However, due to the changing data of the epidemic, there is no scientific estimate of the cure rate and case fatality rate of the epidemic. This study proposes a method to estimate the cure rate and case fatality rate of COVID-19. The ratio of cumulative discharges on a given day to the sum of cumulative discharges on a given day and cumulative deaths before j days is used to estimate the cure rate.Moreover, the case fatality ratio can also be estimated. After simulation calculations, j is statistically appropriate when it is 8-10, and it is also clinically appropriate. When j is 9, based on the available data, it is inferred that the cure rate of this epidemic is about 93% and the case fatality rate is about 7%. This method of estimating the cure rate can be used to evaluate the effectiveness of treatment in different medical schemes and different regions, and has great value and significance for decision-making in the epidemic. improvement of medical conditions, and rich experience in treatment, patients with COVID-19 will be treated more effectively. Consequently, the CR will increase, and the CFR will decrease. Conflict of Interest StatementThe authors declare no conflict of interest.

Dialkyl malonates are important organic intermediates that are widely used as building blocks in organic synthesis. Herein, palladium nanoparticles supported on a triphenylphosphine-functionalized porous polymer were successfully developed as an efficient and recyclable catalyst for the synthesis of dialkyl malonates via the catalytic carbonylation of chloroacetates. The influence of reaction parameters such as solvent, base, and promoter on activity was carefully investigated. With a 1 mol% of palladium usage, excellent yields of dialkyl malonates were obtained. Importantly, the catalyst can be easily separated and reused at least four times, without a significant loss in reactivity. Furthermore, the developed catalyst was also highly active for the alkoxycarbonylation of α-chloro ketones.

The case fatality rate (CFR) can be used to predict the number of potential 19 deaths in the epidemic and thus can reflect the appropriateness and quality of medical 20 measures developed by public health. When a new disease breaks out, it is 21 particularly important to accurately estimate the CFR. However, while the epidemic is 22 still developing, the crude CFR is often lower than the true value and the hospital 23 CFR is often higher than the true value due to differences in occurrence time, patient 24 number, and treatment plans. Therefore, this study proposes a bi-directional correction 25 method to estimate the CFR. COVID-19 data from China were used to evaluate this 26 method. The results show that this method provides more accurate results than both 27 the crude CFR and hospital CFR. Additionally, this method was used to estimate the 28 CFR of COVID-19 in other countries, with an aim to provide a reference for 29 prevention and control decisions for the COVID-19 epidemic and for the evaluation 30 of medical efforts. 31