Visible Light-Mediated Selective Aerobic Oxidation of Alcohols Catalyzed by Disulfide in Batch and Flow.

Selective aerobic oxidation of alcohols in batch and flow can be realized under light irradiation, utilizing disulfide as the photocatalyst, and a variety of primary and secondary alcohols were converted to the corresponding aldehydes or ketones in up to 99% yield and high selectivity. The reaction efficiency could be increased even further by combining a continuous-flow strategy. Detailed mechanistic studies have also been achieved to determine the role of oxygen and disulfides in this oxidation.

Low-Temperature Synthesis of Cyano-Rich Modified Surface-Alkalinized Heterojunctions with Directional Charge Transfer for Photocatalytic In Situ Generation and Consumption of Peroxides.

The synthesis of low-temperature poly(heptazine imide) (PHI) presents a significant challenge. In this context, we have developed a novel low-temperature synthesis strategy for PHI in this work. This strategy involves the introduction of Na+ ions, which etch and disrupt the conjugated structure of carbon nitride (CN) during assisted thermal condensation. This disruption leads to the partial decomposition of the heptazine ring structure, resulting in the formation of C≡N functionalities on the CN surface, which are enriched with hydroxyl groups and undergo cyano modification. The formation of heterojunctions between CN and ZnO, which facilitate charge transfer along an immobilization pathway, accelerated charge transfer processes and improved reactant adsorption as well as electron utilization efficiency. The resulting catalyst was employed for the room temperature, atmospheric pressure, and solvent-free photocatalytic selective oxidation of cumene (CM), achieving a cumene conversion rate of 28.7% and a remarkable selectivity of 92.0% toward the desired product, cumene hydroperoxide (CHP). Furthermore, this CHP induced oxidative reactions, as demonstrated by the successful oxidation of benzylamine to imine and the oxidation of sulfide to sulfoxide, both yielding high product yields. Additionally, the utilization of a continuous-flow device significantly reduces the reaction time required for these oxidation processes. This work not only introduces an innovative approach to environmentally friendly, sustainable, clean, and efficient PHI synthesis but also underscores the promising potential and advantages of carbon nitride-based photocatalysts in the realm of sustainable and green organic transformations.

Bridging Effect of Carbon Nitride with More Negative Conduction Potential and Halogens Promotes the Liquid-Phase Oxidation of Aromatic C-H Bonds.

The selective oxidation of benzyl C-H bonds of alkyl aromatic hydrocarbons under solvent-free conditions by using heterogeneous catalysis is a challenging task. In this work, we designed a carbon nitride photocatalyst with a high charge separation efficiency and a directed charge transfer path, which was doped with Ni and Br in the carbon nitride skeleton. Br was deposited directionally onto the electron-rich Ni surface traps to form a bond with Ni, which acted as a charge transfer bridge connecting CN and Br, resulting in a bridging effect. Photogenerated electrons were transferred from Ni target to Br, and electrons were aggregated to form a directional charge transfer path, thereby enhancing the photocatalytic performance of CN. The photocatalyst was utilized for the selective oxidation of ethylbenzene at room temperature, atmospheric pressure, and solvent-free conditions. Under batch conditions simulating solar irradiation, the conversion of ethylbenzene was 43.3% and the selectivity of the product acetophenone was up to 92.0%. With the continuous flow strategy, the conversion of ethylbenzene was increased to 52.4 and 48.1%, respectively, while the selectivity reached 92.7 and 91.0%, and the reaction time was reduced from 24 to 2.1 h. The catalyst was also found to be broadly applicable for the selective oxidation of C-H bonds in the benzyl position of alkyl aromatic hydrocarbons.

Application of Improved Robot-assisted Laparoscopic Telesurgery with 5G Technology in Urology.

The demand for telesurgery is rising rapidly, but robust evidence regarding the feasibility of its application in urology is still rare. From March to October 2021, a surgeon-controlled surgical robot in a tertiary hospital in Qingdao was used to remotely conduct robot-assisted laparoscopic radical nephrectomy (RN) in 29 patients located in eight primary hospitals. The median round-trip delay was 26 ms (interquartile range [IQR] 5) and the median distance between the primary hospital and the surgeon was 187 km (IQR 57). Both the master unit and the slave unit were guaranteed by network and mechanical engineers, and surgical assistants were well prepared on the patient side to prevent complications. The primary evaluation metric was the success rate, defined as the percentage of patients who underwent successful remote RN without conversion to other surgical procedures and no major intraoperative or postoperative complications. The results demonstrate that the combination of 5G technology and surgical robots is a novel potential telemedicine-based therapy choice for renal tumors. PATIENT SUMMARY: Our study shows that telesurgery using 5G technology is a safe and feasible treatment option for patients with kidney tumors. The total delay between the remote location and the operating rooms where surgery was being performed was just 200 ms. This approach could reduce health care costs and improve the quality of medical services accessed by patients.

Effects of Oxygen: Experimental and VTST/DFT Studies on Cumene Autoxidation with Air under Atmospheric Pressure.

The mechanism of how oxygen affects cumene autoxidation related to temperature is still bewildering. Kinetic analysis of cumene autoxidation with air at a pressure of 1.0 atm was investigated by experiments and variational transition state theory/DFT. Oxygen was the limiting factor for cumene autoxidation above 100 °C, although it had negligible impacts on cumene autoxidation at 70-100 °C. The kinetic analysis by VTST coupled with DFT calculations proved that {k 6,reverse[ROO•]}/{k 7,forward[RH]0 [ROO•]} > 103 (70-120 °C), suggesting that ROO• tended to decompose back to R• and O2 rapidly, whereas it was much slower for ROO• abstracting a hydrogen atom from RH to form ROOH. When the concentration of oxygen was higher than the critical value ([O2]critical), it could not significantly affect the equilibrium concentration of ROO•, which in turn could not affect the autoxidation rate significantly. Besides, the critical oxygen concentration ([O2]critical) was exponentially related to 1/T, which was consistent with Hattori's experimental results.

Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots.

The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104 ). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51-84 % yields and TONs up to 3.4×104 . The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.

Mixotrophic Chlorella pyrenoidosa as cell factory for ultrahigh-efficient removal of ammonium from catalyzer wastewater with valuable algal biomass coproduction through short-time acclimation.

To achieve ultrahigh-efficient ammonium removal and valuable biomass coproduction, Chlorella-mediated short-time acclimation was implemented in photo-fermentation. The results demonstrated short-time acclimation of mixotrophic Chlorella pyrenoidosa could significantly improve NH4+ removal and biomass production in shake flasks. After acclimation through two batch cultures in 5-L photo-fermenter, the maximum NH4+ removal rate (1,400 mg L-1 d-1) were achieved under high NH4+ level (4,750 mg L-1) in batch 3. In 50-L photo-fermenter, through one batch acclimated culture, the maximum NH4+ removal rate (2,212 mg L-1 d-1) and biomass concentration (58.4 g L-1) were achieved in batch 2, with the highest productivities of protein (5.56 g L-1 d-1) and total lipids (5.66 g L-1 d-1). The hypothetical pathway of nutrients assimilation in mixotrophic cells as cell factory was proposed with detailed discussion. This study provided a novel strategy for high-ammonium wastewater treatment without dilution, facilitating the algae-based "waste-to-treasure" bioconversion process for green manufacturing.

5G ultra-remote robot-assisted laparoscopic surgery in China.

BACKGROUND: 5G communication technology has been applied to several fields in telemedicine, but its effectiveness, safety, and stability in remote laparoscopic telesurgery have not been established. Here, we conducted four ultra-remote laparoscopic surgeries on a swine model under the 5G network. The aim of the study was to investigate the effectiveness, safety, and stability of the 5G network in remote laparoscopic telesurgery. METHODS: Four ultra-remote laparoscopic surgeries (network communication distance of nearly 3000 km), including left nephrectomy, partial hepatectomy, cholecystectomy, and cystectomy, were performed on a swine model with a 5G wireless network connection using a domestically produced "MicroHand" surgical robot. The average network delay, operative time, blood loss, and intraoperative complications were recorded. RESULTS: Four laparoscopic telesurgeries were safely performed through a 5G network, with an average network delay of 264 ms (including a mean round-trip transporting delay of 114 ms and a 1.20% data packet loss ratio). The total operation time was 2 h. The total blood loss was 25 ml, and no complications occurred during the procedures. CONCLUSIONS: Ultra-remote laparoscopic surgery can be performed safely and smoothly with 5G wireless network connection using domestically produced equipment. More importantly, our model can provide insights for promoting the future development of telesurgery, especially in areas where Internet cables are difficult to lay or cannot be laid.

High-yield production of biomass, protein and pigments by mixotrophic Chlorella pyrenoidosa through the bioconversion of high ammonium in wastewater.

To achieve a high consumption rate of ammonium with biomass coproduction, the mixotroph Chlorella pyrenoidosa was cultivated in high ammonium-high salinity wastewater medium in this study. The initial cell density, glucose and ammonium concentrations, and light intensity were optimized in shake flasks. A 5-L fermenter with surrounding LED (Light Emitting Diode) and a 50-L fermenter with inlet LED were employed for batch and semicontinuous cultivation. The results demonstrated that the highest contents of protein (56.7% DW) and total pigments (4.48% DW) with productivities of 5.62 g L-1 d-1 and 0.55 mg L-1 d-1, respectively, were obtained in 5-L photofermenter, while the maximum NH4+ consumption rate (1,800 mg L-1 d-1) and biomass yield (23.6 g L-1) were achieved in 50-L photofermenter. This study developed a novel strategy to convert high ammonium in wastewater to high-protein algal biomass, facilitating wastewater bioremediation and nitrogen recycling utilization by the mixotroph C. pyrenoidosa in photofermentation.

Rose bengal as photocatalyst: visible light-mediated Friedel-Crafts alkylation of indoles with nitroalkenes in water.

A novel and facile visible-light-mediated alkylation of indoles and nitroalkenes has been developed. In this protocol, rose bengal acts as a photosensitizer, and environmentally benign water was used as the green and efficient reaction medium. Indoles reacted smoothly with nitroalkenes under the irradiation of visible-light and generated corresponding 3-(2-nitroalkyl)indoles in moderate to good yields (up to 87%).

Visible light-mediated selective α-functionalization of 1,3-dicarbonyl compounds via disulfide induced aerobic oxidation.

A visible light-mediated α-functionalization of 1,3-dicarbonyl compounds with switchable selectivity induced by disulfide is disclosed. Upon irradiation with visible light, the metal- and base-free α-hydroxylation or α-hydroxymethylation reaction proceeded smoothly through a disulfide-catalyzed oxidation under mild conditions. The combination of a continuous-flow strategy could further improve the reaction efficiencies.

Enantioselective photooxygenation of ß-dicarbonyl compounds in batch and flow photomicroreactors.

A series of C-2' modified cinchonine-derived phase-transfer catalysts were synthesized and used in the enantioselective photo-organocatalytic aerobic oxidation of ß-dicarbonyl compounds with excellent yields (up to 97%) and high enantioselectivities (up to 90% ee). Furthermore, the reaction was carried out in a flow photomicroreactor, in which the heterogeneous gas-liquid-liquid asymmetric photocatalytic oxidation reaction was performed affording good yields (up to 97%) and enantioselectivities (up to 86% ee) within 0.89 min.

Visible Light-Induced Aerobic Epoxidation of α,ß-Unsaturated Ketones Mediated by Amidines.

An aerobic photoepoxidation of α,ß-unsaturated ketones driven by visible light in the presence of tetramethylguanidine (3b), tetraphenylporphine (H2TPP), and molecular oxygen under mild conditions was revealed. The corresponding α,ß-epoxy ketones were obtained in yields of up to 94% in 96 h. The reaction time was shortened to 4.6 h by flow synthesis. The mechanism related to singlet oxygen was supported by experiments and density functional theory (DFT) calculations.