Insights into Thiourea-Based Bifunctional Catalysts for Efficient Conversion of CO2 to Cyclic Carbonates.

The bifunctional thiourea catalyst system with both electrophilic and nucleophilic centers has been certified to be effective for fixing CO2 under mild reaction conditions; however, many questions remain, especially concerning the relationship between structure and performance. Herein, we systematically studied a series of such bifunctional catalysts with different chain lengths, nucleophilic anions, and substituents, which impact obvious influence on the catalytic performance. The activation energies of catalysts with different chain lengths are calculated via in situ IR. On this basis, we disclosed for the first time that the spacer length of tetramethylene -(CH2)6- is the optimal spatial effect for the coupling of epoxides and CO2. Particularly, the single crystal X-ray diffraction analysis of the molecular structures of the bifunctional catalyst C8 indicated the discovery of the existence of interaction force between the sulfur atom on the thiourea group and one hydrogen atom on the benzene ring, as well as the intermolecular hydrogen bonding interaction of the bromide (Br-) and two NH groups on the thiourea group. The catalyst structure performance, direct observation of the crystal structure, the thermodynamic study, and a wide range of substrates (12 examples) should be informative on the optimization of the existing catalysts or the design of new catalysts in the future.

Clinical feasibility of laparoscopic left lateral segment liver resection with magnetic anchor technique: The first clinical study from China.

BACKGROUND: Magnetic anchor technique (MAT) has been applied in laparoscopic cholecystectomy and laparoscopic appendectomy, but has not been reported in laparoscopic partial hepatectomy. AIM: To evaluate the feasibility of the MAT in laparoscopic left lateral segment liver resection. METHODS: Retrospective analysis was conducted on the clinical data of eight patients who underwent laparoscopic left lateral segment liver resection assisted by MAT in our department from July 2020 to November 2021. The Y-Z magnetic anchor devices (Y-Z MADs) was independently designed and developed by the author of this paper, which consists of the anchor magnet and magnetic grasping apparatus. Surgical time, intraoperative blood loss, intraoperative accidents, operator experience, postoperative incision pain score, postoperative complications, and other indicators were evaluated and analyzed. RESULTS: All eight patients underwent a MAT-assisted laparoscopic left lateral segment liver resection, including three patients undertaking conventional 5-port and five patients having a transumbilical single-port operation. The mean operation time was 138 ± 34.32 min (range 95-185 min) and the mean intraoperative blood loss was 123 ± 88.60 mL (range 20-300 mL). No adverse events occurred during the operation. The Y-Z MADs showed good workability and maneuverability in both tissue and organ exposure. In particular, the operators did not experience either a "chopstick" or "sword-fight" effect in the single-port laparoscopic operation. CONCLUSION: The results show that the MAT is safe and feasible for laparoscopic left lateral segment liver resection, especially, exhibits its unique abettance for transumbilical single-port laparoscopic left lateral segment liver resection.

Variations of high temperature from 1961 to 2019 in Liaoning Province, China.

Better understanding of the changes in high-temperature would be helpful for improving the monitoring of hot extremes and mitigating their impacts towards a sustainable regional development. Based on the data of daily maximum temperature, relative humidity, and wind speed from 23 meteorological stations in Liaoning Province in summer (June to August) during 1961 to 2019, we analyzed the variations of daily maximum temperature (Tx), daily maximum apparent temperature (AT), and heat wave events (3 consecutive days ≥35 ℃). The effects of meteorological variables on daily maximum apparent temperature were examined by the grey relational analysis method. The results showed that the average Tx (AT) of all stations was 26.19 (27.35), 28.29 (31.13), and 28.14 (31.08) ℃, respectively, while the average trends in Tx (AT) was 0.17 (0.38), 0.20 (0.35), and 0.17 (0.28) ℃·(10 a)-1, respectively, in June, July and August during 1961 to 2019. The average AT and its trends in each month were larger than the Tx. From June to August, there was significant negative correlation between Tx (AT) and its climate tendency rate, indicating that the range of warming in the area with low Tx and AT was larger than that in the area with high values. We should therefore pay more attention to the protection against high temperature in the low value area of Tx and AT in summer. From June to August, the average number of hot days with AT ≥ 35 ℃ was 0.85 d·a-1, with an average increase rate of 0.20 d·(10 a)-1. Hot days were signifi-cantly more in June and July than in August. The area with more hot days was mainly located in the west of Liaoning, and the area with less hot days was mainly located in the south and coastal areas. The number of heat wave events was 0.071 times per year, which was large in western Liaoning. There was no high temperature heat wave event in the southern and coastal areas of Liaoning. The correlation analysis showed that the AT in June was strongly associated with relative humidity, while AT in July and August had the closest relationship with Tx. Therefore, the importance of relative humidity on the monitoring and forecasting of high temperature and hot weather cannot be ignored.

[Identification and characteristics of multiple agrometeorological disaster of maize in Liaoning Province, China]. / 辽宁省玉米复合农业气象灾害判识及特征.

Multiple agrometeorological disaster (MAD) occurs simultaneously in maize production. In order to ascertain the occurrence regularity and characteristics of MAD of maize in Liaoning Pro-vince, we defined and classified MAD, identified MAD of 50 meteorological stations in the maize growing season of Liaoning Province from 1961 to 2017, and examined the effects of MAD on maize yield in typical years. The results showed that the occurrence range of MAD was higher in most years from 1961 to 2017 than that of single agrometeorological disaster (SAD), and that the occurrence frequency of MAD was higher in most areas than that of SAD. The major MAD in Liaoning Province was drought in multiple periods (M1-D), followed by the combination of drought and delayed cold damage (M2-DC). The occurrence range of M1-D showed an upward trend from 1961 to 2017, whereas other MAD types showed a downward trend. After analyzing the occurrence of MAD in the typical years of maize yield reduction, we found that the occurrence frequency of M1-D and M2-DC was higher.

Ligand-induced dependence of charge transfer in nanotube-quantum dot heterostructures.

As a model system to probe ligand-dependent charge transfer in complex composite heterostructures, we fabricated double-walled carbon nanotube (DWNT)-CdSe quantum dot (QD) composites. Whereas the average diameter of the QDs probed was kept fixed at ∼4.1 nm and the nanotubes analyzed were similarly oxidatively processed, by contrast, the ligands used to mediate the covalent attachment between the QDs and DWNTs were systematically varied to include p-phenylenediamine (PPD), 2-aminoethanethiol (AET), and 4-aminothiophenol (ATP). Herein, we have put forth a unique compilation of complementary data from experiment and theory, including results from transmission electron microscopy (TEM), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, Raman spectroscopy, electrical transport measurements, and theoretical modeling studies, in order to fundamentally assess the nature of the charge transfer between CdSe QDs and DWNTs, as a function of the structure of various, intervening bridging ligand molecules. Specifically, we correlated evidence of charge transfer as manifested by changes and shifts associated with NEXAFS intensities, Raman peak positions, and threshold voltages both before and after CdSe QD deposition onto the underlying DWNT surface. Importantly, for the first time ever in these types of nanoscale composite systems, we have sought to use theoretical modeling to justify and account for our experimental results. Our overall data suggest that (i) QD coverage density on the DWNTs varies, based upon the different ligand pendant groups used and that (ii) the presence of a π-conjugated carbon framework within the ligands themselves coupled with the electron affinity of their pendant groups collectively play important roles in the resulting charge transfer from QDs to the underlying CNTs.