Dithiol treatments enhancing the efficiency of hybrid solar cells based on PTB7 and CdSe nanorods

We report the fabrication of polymer/inorganic hybrid solar cells (HSCs) based on CdSe nanorods (NRs) and the semiconducting polymer PTB7. The power conversion efficiency of HSCs can be significantly enhanced by engineering the polymer/nanocrystal interface with ethanedithiol (EDT) and 1,4-benzenedithiol (1,4-BDT) treatments and reached 2.58% and 2.79%, respectively. These results were preferable to that of a pyridine-coated NR-based device (1.75%). This improvement was attributed to the thiol groups of EDT and 1,4-BDT, which can tightly coordinate the Cd ions to form Cd-thialate on CdSe NR surfaces, thereby effectively passivating the NR surface and reducing the active layer defects. Therefore, the rate of exciton generation and dissociation was enhanced and led to the improvement of the device performance

Differences in Gut Microbiota between Healthy Individuals and Patients with Perianal Abscess before and after Surgery

Surgery is the most important treatment for perianal abscesses. However, the gut microbiota of patients with perianal abscess and the effects of perianal abscess on the gut microbiota after surgery are unknown. In this study, significant changes in interleukin 6 and tumor necrosis factor-α in the blood of healthy subjects, patients with perianal abscesses, and patients after perianal abscess surgery were identified. 16S rRNA gene sequencing technology was used to detect the changes in the gut microbiota among 30 healthy individuals and 30 patients with perianal abscess before and after surgery. Venn diagrams and alpha diversity analyses indicated differences in the abundance and uniformity of gut microbiota between the healthy individuals and patients with perianal abscesses before and after surgery. Beta diversity analysis indicated that the grouping effects among the control, abscess, and surgery groups were good. The classification and compositional analysis showed significant differences in the gut microbiota between healthy individuals and patients with perianal abscesses before and after surgery. LEfSe analysis, random forest analysis, and ROC curve analysis showed that Klebsiella (AUC=0.7467) and Bilophila (AUC=0.72) could be potential biomarkers for the diagnosis of perianal abscess. The functional prediction results showed that the differential microbiota is significantly enriched in the pathways related to nutrition and drug metabolism. This study may have important implications for the clinical management and prognostic assessment of patients with perianal abscesses

Understanding of dynamic contacting behaviors of underwater gas bubbles on solid surfaces

Understanding of dynamic behaviors of gas bubbles on solid surfaces has significant impacts on gas-involving electrochemical reactions, mineral flotation and so on in industry. Contact angle (θ) is widely employed to characterize the wetting behaviors of bubbles on solid surfaces; however, it usually fluctuates within the bubble’s advancing (θa) and receding (θr) range. Although the term of most-stable contact angle (θms) was defined previously as the closest valuable approximation for thermodynamically meaningful contact angle for a droplet on solid surface, it has not been widely appreciated; and the precise θms measurement methods are inadequate to describe bubbles’ wetting behaviors on solid surfaces. Herein, we proposed to take θms as the mean value of θa and θr, as a more accurate descriptor of gas bubbles’ dynamic behaviors on non-ideal solid surface, as similar to the definition of droplets’ θms on solid surfaces. The feasibility and accuracy of the proposed θms have been evidenced by recording the bubbles’ contacting behaviors on solid surfaces with varied wettabilities. In addition, it was found that the contact angle hysteresis (δ), as the difference between θa and θr, reached its maximum value when θms approached to 90°, regardless of the roughness (r) of substrates. Finally, built on the above concept, lateral adhesion force (ƒ) of gas bubble on solid interface, which worked on the three-phase contact line (TPCL) of individual bubble on a solid surface against its lateral motion during the bubble advancing or receding process, was described quantitatively by combining θa, θr and liquid-gas interfacial tension (γlg). Experimental and theoretical data jointly confirmed that ƒ reached its maximum value at θms~90°, namely the “super-sticky” state, which described the dynamically most sluggish movement of bubble along the solid surface

Anti-buoyancy and unidirectional gas evolution by Janus electrodes with asymmetric wettability

The bubbles electrochemically generated by gas evolution reactions are commonly driven off the electrode by buoyancy, a weak force used to overcome bubble adhesion barriers, leading to low gas transporting efficiency. Herein, a Janus electrode with asymmetric wettability has been prepared by modifying two sides of a porous stainless-steel mesh electrode, with superhydrophobic polytetrafluoroethylene (PTFE) and Pt/C (or Ir/C) catalyst with well-balanced hydrophobicity, respectively; affording unidirectional transportation of as-formed gaseous hydrogen and oxygen from the catalyst side to the gas-collecting side during water splitting. “Bubble-free” electrolysis was realized when “floating” the Janus electrode on the electrolyte. Anti-buoyancy through-mesh bubble transportation was observed when immersing the electrode with PTFE side downward. The wettability gradient within the electrode endowed sticky states of bubbles on the catalyst side, resulting in efficient “bubble-free” gas transportation with 15 folds higher current density than submerged states