Porous Polypyrrolidines for Highly Efficient Recovery of Precious Metals through Reductive Adsorption Mechanism.

The recycling and utilization of precious metals have emerged as a critical research focus in advancing the development of the circular economy. Among numerous methods for recovering precious metals such as gold, adsorbents with both high adsorption selectivity and capacity have become key technologies. This article incorporated the N-phenylpyrrolidine into a flexible porous polynorbornene backbone to create a class of distinctive porous organic polymers, named BIT-POP-14-BIT-POP-17. Through a reductive capture mechanism, the reductive adsorption sites of N-phenylpyrrolidine coordinate selectively with precious metals, the reduced metal is captured by the hierarchically porous polymers with flexible backbone. This approach leads to remarkable gold recovery efficiency, achieving a record of 2321 mg g-1 at ambient conditions, and 3020 mg g-1 under UV light, surpassing the theoretical limit. The porous polymers are filled in a column for a continuous uptake of gold from waste printed circuit boards (PCBs), showing recovery efficiency toward gold as high as 95% after 84 h. Overall, this work offers a new perspective on designing novel adsorbents for precious metal recovery, providing inspiration for researchers to explore novel adsorption modes and contribute to the advancement of the circular economy.

Evaluation of retinal structural and functional changes after silicone oil removal in patients with rhegmatogenous retinal detachment: a retrospective study.

BACKGROUND: To evaluate retinal structural and functional changes after silicone oil (SO) removal in eyes with macula-off rhegmatogenous retinal detachment (RRD). METHODS: Best-corrected visual acuity (BCVA) testing, microperimetry, and optical coherence tomography angiography were performed in 48 eyes with macula-off RRD before and 3 months after SO removal. The values of healthy contralateral eyes were used as control data. Correlations between retinal vessel density (VD), retinal nerve fiber layer thickness (RNFLT), the interval between retinal detachment and surgery, the duration of SO tamponade, the follow-up time after SO removal, and visual function were analyzed. RESULTS: Significant increases in 2˚ fixation rate (FR), 4˚ FR, 2˚ mean retinal sensitivity (MRS), 6˚ MRS, parafoveal superficial capillary plexus VD and RNFLT were observed after SO removal (all P < 0.05). The increase of 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade and the follow-up time after SO removal respectively (all P < 0.05). The last 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade, the interval between retinal detachment and surgery, and the follow-up time after SO removal (all P < 0.01). The last FR in RRD eyes was close to that of contralateral eyes (P > 0.05). CONCLUSION: Retinal structure and function improved to different degrees after SO removal. Fixation stability and retinal sensitivity increased more than BCVA postoperatively. Retinal sensitivity, which was affected by the interval between retinal detachment and surgery and the duration of SO tamponade, gradually recovered after SO removal.

Peripapillary changes after vitrectomy and silicone oil tamponade for rhegmatogenous retinal detachment.

PURPOSE: To evaluate the peripapillary changes after vitrectomy and silicone oil (SO) tamponade in eyes with rhegmatogenous retinal detachment (RRD). METHODS: In this study, 25-gauge vitrectomy with SO tamponade was performed in 22 eyes with RRD. The radial peripapillary capillary (RPC) vessel density (VD) and retinal nerve fiber layer thickness (RNFLT) were assessed by optical coherence tomography angiography at 2, 4, 8, and 12 weeks postoperatively. The values of healthy fellow eyes were used as controls. RESULTS: The global RPC VDs were significantly lower in the eyes with RRD than in fellow healthy eyes at 2 weeks (P < 0.001), and increased at 4 weeks, then decreased over time after surgery (F = 1.046, P = 0.377). The RPC VDs in the superior-hemifield were lower than those in the inferior-hemifield at 12 weeks postoperatively (t = -2.844, P = 0.010). The global RNFLTs decreased gradually after vitrectomy in the eyes with RRD (F = 1.312, P = 0.276). The RNFLTs in the superior-hemifield were thinner than those in the inferior-hemifield at 12 weeks postoperatively (t = -2.222, P = 0.037). The global, superior, and inferior RNFLTs were correlated with corresponding RPC VDs in the eyes with RRD at all time-points postoperatively (P < 0.05). CONCLUSION: RRD resulted in the decrease of RPC VDs. The RPC VDs recovered in the early postoperative period but were still lower than the normal level. Long-term application of SO tamponade resulted in the reduction of peripapillary VDs secondary to loss of RNFLTs.

Evaluation of macular vessel density changes after vitrectomy with silicone oil tamponade in patients with rhegmatogenous retinal detachment.

AIM: To evaluate macular microvasculature changes in eyes after pars plana vitrectomy (PPV) and intraocular silicone oil (SO) tamponade for macula-off rhegmatogenous retinal detachment (RRD) using optical coherence tomography angiography (OCTA). METHODS: Totally 19 eyes (19 patients) with macula-off RRD who underwent PPV and intraocular SO tamponade were retrospectively reviewed. The parafoveal superficial capillary plexus (SCP) vessel density (VD), deep capillary plexus (DCP) VD, choriocapillaris plexus (CCP) VD, and foveal macular thickness were evaluated using OCTA throughout 16wk postoperatively. The values of healthy fellow eyes were used as control. RESULTS: The parafoveal SCP, DCP, and CCP VDs were significant increased over time in RRD eyes during the 12wk postoperatively, then decreased at 16wk postoperatively (all P<0.01). The ratios of RRD eyes and fellow healthy eyes (r/f ratios) of the SCP and DCP VDs were lower than those of the CCP VD postoperatively (all P<0.05). There were not significant differences in the r/f ratios between SCP and DCP VDs postoperatively (all P>0.05). CONCLUSION: The parafoveal SCP, DCP, and CCP VDs gradually recover over time after PPV surgery with SO tamponade. Long-time SO tamponade might decrease postoperative macular VDs. Compared to parafoveal CCP VD, the parafoveal SCP and DCP VDs were more vulnerable in RRD eyes postoperatively.

Monitoring of pH changes in a live rat brain with MoS2/PAN functionalized microneedles.

Monitoring the dynamic pH changes in vivo remains very essential to comprehend the function of pH in various physiological processes. In this study, we report a high-performance electrochemical pH microneedle based on an acupuncture needle (AN) for real-time monitoring of pH changes in a rat brain. The pH microneedle was prepared by a layer-to-layer assembly of molybdenum disulfide (MoS2) nanosheets and polyaniline (PAN), with an attempt to achieve a highly sensitive detection of hydrogen ions (H+). The as-prepared PAN/MoS2/AN exhibited a high Nernstian response of -51.2 mV per pH over a wide pH range from 3.0 to 9.0, and excellent selectivity toward pH against other potential interfering species in the brain. Moreover, the corresponding open circuit potential rapidly increased and decreased when Na2CO3 or NaH2PO4 was injected into the rat brain, respectively, demonstrating that the PAN/MoS2/AN has an excellent response toward pH changes in vivo. This work provides a new potentiometric method for real-time monitoring of dynamic pH changes in vivo with high reliability and stability.

MoS2/Pt nanocomposite-functionalized microneedle for real-time monitoring of hydrogen peroxide release from living cells.

This work describes the adaptive use of a conventional stainless steel acupuncture needle as the electrode substrate for construction of a molybdenum disulfide (MoS2) and platinum nanoparticles (PtNPs) layer-modified microneedle sensor for real-time monitoring of hydrogen peroxide (H2O2) release from living cells. To construct the nanocomposite-functionalized microneedle, the needle surface was first coated with a gold film by ion sputtering to enhance the conductivity. Subsequently, an electrochemical deposition method was successfully employed to deposit MoS2 nanosheet and Pt nanoparticles on the needle tip as the sensing interface. Electrochemical study demonstrated that the MoS2/PtNPs nanocomposite-modified needle exhibited excellent catalytic performance and low over-potential toward the reduction of H2O2. Not only did the microneedle achieve a wide linear range from 1 to 100 µmol L-1 with a limit of detection down to 0.686 µmol L-1, but it also realized the highly specific detection of H2O2. Owing to these remarkable analytical advantages, the prepared microneedle was applied to determine H2O2 release from living cells with satisfactory results. The MoS2/PtNPs nanocomposite-functionalized microneedle sensor is simple and affordable, and can serve as a promising electrochemical nonenzymatic sensing platform. Moreover, this superfine needle sensor shows great potential for real-time monitoring of reactive oxygen species in vivo with minimal damage.