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To investigate the effects of nano-SiO2 (NS) and polyvinyl alcohol (PVA) fibers on the durability and mechanical properties of cementitious composites subjected to saline freeze–thaw cycling, a series of PVA fiber-reinforced cementitious composite (PFRCC) specimens were prepared using various fiber contents, and a series of NS and PVA fiber-reinforced cementitious composite (NPFRCC) specimens were prepared using various combinations of NS and fiber contents. Durability and fracture toughness tests were subsequently conducted on the specimens after different numbers of saline freeze–thaw cycles. The results indicate that the degradation of material properties can be divided into slow and accelerated damage stages before/after 50 freeze–thaw cycles. The durability and fracture toughness of the specimen series tended to increase, then decrease with increasing NS and PVA contents, suggesting optimum levels. When the PVA fiber content was 0.5%, PFRCC specimens had the best durability after saline freeze–thaw cycles; when the NS and PVA fiber contents were 1.0% and 0.5%, respectively, NPFRCC specimens had the best durability and fracture properties, and the initiation toughness, destabilization toughness, and fracture energy after 100 saline freeze–thaw cycles were 120.69%, 160.02%, and 451.31%, respectively. The results of this study may guide future exploration of the durability and mechanical properties of concrete subjected to freeze–thaw action. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the effect of calcium nitrite (CN) on improving the mechanical properties and microstructures of early-frozen cement paste. Cement pastes containing 1%, 1.5%, 2%, 2.5%, and 3% CN were prepared. One batch of samples was frozen at −6 °C for 7 days and then cured at 20 °C, and the other batch of samples was directly cured at 20 °C as a control. The compressive strength, ultrasonic pulse velocity, and resistivity of all specimens at different target ages were measured under these two curing conditions. The hydration products and microstructures of typical samples were observed using XRD and scanning SEM. The results showed that the addition of 1.5% CN could promote cement hydration and enhance slurry densification, thereby increasing the compressive strength, ultrasonic pulse velocity, and electrical resistivity of the slurry, and positively affecting the early freezing resistance of the slurry. However, when the CN dosage exceeded 1.5%, the internal structure of the slurry was loose and porous due to the generation of a large amount of nitrite–AFm, which negatively affects the properties of the cement paste. In addition, the effectiveness of CN is only limited to temperature environments above −6 °C. Concrete antifreeze suitable for lower temperatures still requires further research. [ABSTRACT FROM AUTHOR]

Background and purpose: Inhibitors of poly (ADP-ribose) polymerase (PARPi) has been shown in multiple clinical trials to benefit survival in patients with homologous recombination repair (HRR) gene mutations in metastatic castration-resistant prostate cancer (mCRPC). Fluzoparib has been approved for the treatment of ovarian, fallopian tube and peritoneal cancers, but no data have been reported for prostate cancer. The purpose of this study was to evaluate the efficacy and safety of fluzoparib in the treatment of patients with prostate cancer. Methods: The clinical data of 13 mCRPC patients treated with fluzoparib alone or fluzoparib combined with abiraterone or SHR3680 (androgen receptor antagonist) in 9 hospitals nationwide including Fudan University Shanghai Cancer Center from January 1, 2020 to February 1, 2021 were retrospectively analyzed. Genetic mutation data, survival data, adverse reactions and other data were obtained through outpatient cases or telephone follow-up. Results: Among the 13 patients, 3 patients were treated with fluzoparib alone, 8 patients were treated with fluzoparib combined with abiraterone, and 2 patients were treated with fluzoparib combined with SHR3680. All the 3 patients treated with monotherapy carried HRR gene mutations, and all had prostate-specific antigen (PSA); among those, 2 patients (66.7%) had PSA decrease of more than 50%. All the 8 patients treated with fluzoparib combined with abiraterone had been resistant to abiraterone at the earlier stage, and the genetic testing results showed that 2 patients did not carry HRR pathogenic mutation, and 1 patient did not receive genetic testing. Among the 8 patients, only 1 patient without HRR pathogenic mutation had an increase in PSA after receiving the combined treatment, while the remaining 7 patients (87.5%) had a decrease in PSA. PSA decreased by more than 50% in 3 patients (37.5%) and 90% in 2 patients (25.0%). The 2 patients treated with fluzoparib combined with SHR3680 had been resistant to abiraterone and docetaxel at the earlier stage, one patient had no genetic test and no PSA response, and the other patient had no DNA damage repair (DDR) gene mutation, however, decreased by more than 50%. At the same time, 61.5% (8/13) of the patients showed different degrees of adverse reactions, the main adverse reactions were anemia, joint pain, loss of appetite and fatigue; 23.1% (3/13) of the patients developed grade 3 anemia, of whom 1 patient terminated the treatment. Conclusion: Fluzoparib shows promising clinical prospects, and is well tolerated in both monotherapy and combination therapy. However, this conclusion needs to be further confirmed in prospective clinical studies with larger sample size.