Influences of Propofol, Ciprofol and Remimazolam on Dreaming During Anesthesia for Gastrointestinal Endoscopy: A Randomized Double-Blind Parallel-Design Trial.

Purpose: To compare the influences of propofol, ciprofol and remimazolam on dreaming during painless gastrointestinal endoscopy. Methods: This study was a single-center, prospective, parallel-design, double-blind, randomized clinical trial. Between May 2023 and October 2023, patients undergoing elective painless gastrointestinal endoscopy were recruited and randomly allocated into one of the three groups. Demographic data, intraoperative information, incidence of dreaming, insufficient anesthesia and intraoperative awareness, type of dream, patient satisfaction score, adverse events, and improvement of sleep quality were collected. Results: The difference in incidence of dreaming among the three groups was not significant (33.33% vs 48.33% vs 41.67%, p=0.061). The number of patients with intraoperative hypotension in the propofol group was larger than that of the remimazolam group (32 vs 12, p=0.001). However, the cases of intraoperative hypotension between propofol group and ciprofol group or ciprofol group and remimazolam group were comparable (32 vs 22, p=0.122; 22 vs 12, p=0.064). The percentage of insufficient anesthesia between propofol group and remimazolam group was significant (13.33% vs 1.67%, p=0.001), while no statistical difference was detected between propofol group and remimazolam group or ciprofol group and remimazolam group (13.33% vs 5.00%, p=0.025; 5.00% vs 1.67%, p=0.150). The ability of propofol to improve sleep quality at 1st post-examination day was significantly better than that of remimazolam (86.21% vs 72.88%, p=0.015), while it was not significant between propofol group and ciprofol group or ciprofol group and remimazolam group (86.21% vs 80.36%, p=0.236; 72.88% vs. 72.88%, p=0.181). Incidence of intraoperative awareness, intraoperative hypoxia, type of dream, satisfaction score, adverse events during recovery, and sleep improvement on the 7th post-examination day was not significant among the groups. Conclusion: Anesthesia with propofol, ciprofol and remimazolam, respectively, for gastrointestinal endoscopy did not induce statistical difference in the incidence of dreaming, despite that all of them are more likely to induce pleasant dreams.

Dielectric and Wavefunction Engineering of Electron Spin Lifetime in Colloidal Nanoplatelet Heterostructures.

Colloidal semiconductor nanoplatelets (NPLs) have emerged as low-cost and free-standing alternates of traditional quantum wells. The giant heavy- and light-hole splitting in NPLs allows for efficient optical spin injection. However, the electron spin lifetimes for prototypical CdSe NPLs are within a few picoseconds, likely limited by strong electron-hole exchange in these quantum- and dielectric-confined materials. Here how this hurdle can be overcome with engineered NPL-heterostructures is demonstrated. By constructing type-I CdSe/ZnS core/shell NPLs, dielectric screening inside the core is strongly enhanced, prolonging the electron spin polarization time (τesp) to over 30 ps (or 60 ps electron spin-flip time). Alternatively, by growing type-II CdSe/CdTe core/crown NPLs to spatially separate electron and hole wavefunctions, the electron-hole exchange is strongly suppressed, resulting in τesp as long as 300 ps at room temperature. This study not only exemplifies how the well-established synthetic chemistry of colloidal heterostructures can aid in spin dynamics control but also establishes the feasibility of room-temperature coherent spin manipulation in colloidal NPLs.

Heterojunction photocatalyst FeS2/g-C3N5 for activating sulfites to degrade tetracycline: A stable degradation system based on heterogeneous processes.

The UV/sulfite system is a promising source of •SO4- and/or •OH, but its application is largely limited by the use of UV light due to its high cost and high energy consumption. Graphite carbon nitride (g-C3N5), as a new photocatalytic material, has better visible light absorption capacity and narrower band gap than g-C3N4, which is expected to activate sulfite under visible light to solve this problem. Herein, a novel FeS2/CN heterojunction material based on g-C3N5 was constructed by hydrothermal in-situ synthesis method and successfully activated sulfite, which was confirmed by tetracycline degradation experiments in water. Under optimized conditions, the degradation rate of TC in 1 h reached 96%. The experimental results revealed that the FeS2/CN heterostructure enhances the absorption of visible light and inhibits the recombination of carriers, enabling more electrons and holes to be utilized. Holes play a major role in the degradation reaction, promote the sulfite chain reaction, and effectively regulate the cycle of Fe2+ and Fe3+ in the solution. Iron ion leaching is negligible and the degradation reaction remains stable at pH 5-9.

Scrutinizing the interaction between metribuzin with glutathione reductase 2 from Arabidopsis thaliana: insight into the molecular toxicity in agriculture.

As one of the triazine herbicides with widespread usage in agriculture, metribuzin exerted nonnegligible hazardous effects on plants via excessive accumulation of reactive oxygen species and destruction of antioxidant enzymes, but the underlying harmful mechanism of metribuzin-induced oxidative damage to plants has never been exploited. Here, Arabidopsis thaliana glutathione reductase 2 (AtGR2) was employed as the biomarker to evaluate the adverse impacts of metribuzin on plants. The fluorescence intensity of AtGR2 was decreased based on the static quenching mechanism with the prediction of a single binding site toward metribuzin, and the complex formation was presumed to be mainly impelled by hydrogen bonding and van der Waals forces from the negative ΔH and ΔS. In addition, the loosened and unfolded skeleton of AtGR2 along with the increased hydrophilicity around the tryptophan residues were investigated. Besides, the glutathione reductase activity of AtGR2 was also destroyed due to structural and conformational changes. At last, the severe inhibiting growth of Arabidopsis seedling roots was discovered under metribuzin exposure. Hence, the evaluation of the molecular interaction mechanism of AtGR2 with metribuzin will establish valuable assessments of the toxic effects of metribuzin on plants.

Colloidal n-Doped CdSe and CdSe/ZnS Nanoplatelets.

Colloidal semiconductor nanoplatelets (NPLs) are chemical versions of well-studied quantum wells (QWs). For QWs, gating and carrier doping are standard tools to manipulate their optical, electric, or magnetic properties. It would be highly desirable to use pure chemical methods to dope extra charge carriers into free-standing colloidal NPLs to achieve a similar level of manipulation. Here we report colloidal n-doped CdSe and CdSe/ZnS NPLs achieved through a photochemical doping method. The extra electrons doped into the conduction band edges are evidenced by exciton absorption bleaches recoverable through dedoping and the appearance of new intersub-band transitions in the near-infrared. A high surface ligand coverage is the key to successful doping; otherwise, the doped electrons can be depleted likely by unpassivated surface cations. Large trion binding energies of 20-30 meV are found for the n-doped CdSe NPLs, which, in contrast, are reduced by 1 order of magnitude in CdSe/ZnS core/shell NPLs due to dielectric screening. Furthermore, we identify a long-lived negative trion with a lifetime of 1.5-1.6 ns that is likely dominated by radiative recombination.

Exploring the toxic interactions between Bisphenol A and glutathione peroxidase 6 from Arabidopsis thaliana.

As primary industrial raw material, the widespread usage of bisphenol A (BPA) has resulted in sustained release and accumulation in the environment. Besides its endocrine-disrupting character, BPA was reported to generate excessive reactive oxygen species (ROS). However, the potential toxic mechanisms of the BPA-induced oxidative damage to plants were poorly understood. In this study, glutathione peroxidase 6 from Arabidopsis thaliana (AtGPX6) was regarded as biomarker to investigate the toxic effects of BPA on plants by multi-spectroscopic techniques and molecular docking method. Firstly, BPA effectively quenched the intrinsic fluorescence of AtGPX6 via static quenching mechanism, and a single binding site of AtGPX6 towards BPA was presumed. Moreover, the binding force was mainly driven by van der Waals forces and hydrogen bonding based on the negative values of ΔH0 and ΔS0, which was consistent with the molecular docking result. In addition, the conformational changes of AtGPX6 accompanied with the enhancement of the hydrophilicity around the tryptophan residues upon the combination with BPA, were evaluated through the combination of the fluorescence, UV-visible absorption and Circular dichroism (CD) spectroscopy. Finally, the inhibitory impact on the development of Arabidopsis seedling roots was observed under BPA exposure. Therefore, the exploration of the molecular mechanism of AtGPX6 with BPA would provide valuable assessments on the toxic effects of BPA on plants.

Spin blockade and phonon bottleneck for hot electron relaxation observed in n-doped colloidal quantum dots.

Understanding and manipulating hot electron dynamics in semiconductors may enable disruptive energy conversion schemes. Hot electrons in bulk semiconductors usually relax via electron-phonon scattering on a sub-picosecond timescale. Quantum-confined semiconductors such as quantum dots offer a unique platform to prolong hot electron lifetime through their size-tunable electronic structures. Here, we study hot electron relaxation in electron-doped (n-doped) colloidal CdSe quantum dots. For lightly-doped dots we observe a slow 1Pe hot electron relaxation (~10 picosecond) resulting from a Pauli spin blockade of the preoccupying 1Se electron. For heavily-doped dots, a large number of electrons residing in the surface states introduce picosecond Auger recombination which annihilates the valance band hole, allowing us to observe 300-picosecond-long hot electrons as a manifestation of a phonon bottleneck effect. This brings the hot electron energy loss rate to a level of sub-meV per picosecond from a usual level of 1 eV per picosecond. These results offer exciting opportunities of hot electron harvesting by exploiting carrier-carrier, carrier-phonon and spin-spin interactions in doped quantum dots.

Electron and Hole Spin Relaxation in CdSe Colloidal Nanoplatelets.

Solution-processed quantum-confined nanocrystals are important building blocks for scalable implementation of quantum information science. Extensive studies on colloidal quantum dots (QDs) have revealed subpicosecond hole spin relaxation, whereas the electron spin dynamics remains difficult to probe. Here we study electron and hole spin dynamics in CdSe colloidal nanoplatelets (also called quantum wells) of varying thicknesses using circularly polarized transient absorption spectroscopy at room temperature. The clear spectroscopic features of transition bands associated with heavy, light, and spin-orbit split-off holes enabled separate probes of electron and hole dynamics. The hole spin-flip occurred within ∼200 fs, arising from strong spin-orbit coupling in the valence band. The electron spin lifetime decreased from 6.2 to 2.2 ps as the platelet thickness is reduced from 6 to 4 monolayers, reflecting an exchange interaction between the electron and the hole and/or surface dangling bond spins enhanced by quantum confinement.

CO2 reduction catalyzed by mercaptopteridine on glassy carbon.

The catalytic reduction of CO2 is of great current interest because of its role in climate change and the energy cycle. We report a pterin electrocatalyst, 6,7-dimethyl-4-hydroxy-2-mercaptopteridine (PTE), that catalyzes the reduction of CO2 and formic acid on a glassy carbon electrode. Pterins are natural cofactors for a wide range of enzymes, functioning as redox mediators and C1 carriers, but they have not been exploited as electrocatalysts. Bulk electrolysis of a saturated CO2 solution in the presence of the PTE catalyst produces methanol, as confirmed by gas chromatography and (13)C NMR spectroscopy, with a Faradaic efficiency of 10-23%. FTIR spectroelectrochemistry detected a progression of two-electron reduction products during bulk electrolysis, including formate, aqueous formaldehyde, and methanol. A transient intermediate was also detected by FTIR and tentatively assigned as a PTE carbamate. The results demonstrate that PTE catalyzes the reduction of CO2 at low overpotential and without the involvement of any metal.

A non-intermetallic PtPb/C catalyst of hollow structure with high activity and stability for electrooxidation of formic acid.

A non-intermetallic PtPb/C catalyst of hollow structure is synthesized through a simple reduction method, and exhibits an activity as high as 3.6 times that of commercial Pd black and a much higher stability for electrooxidation of formic acid.