Sonographic Findings of Vascular Signals for Retained Products of Conception in Women Following First-Trimester Termination of Pregnancy.

OBJECTIVES: To evaluate the occurrence of retained products of conception (RPOC) after termination of pregnancy in the first trimester and to assess the vascular signals with transvaginal ultrasonography (TVUS) examination in the detection of retained products. METHODS: A retrospective cohort study was performed using TVUS examination in patients following termination of pregnancy. In cases of RPOC, 3 scales of vascular signal were identified: type 1, no or small amount, spot flow signals; type 2, medium amount, strip-like flow signals; type 3, rich amount, circumferential-like flow signals. The correlation between vascular signals and placenta accreta spectrum (PAS) staging was proposed by sonography and histopathology findings. RESULTS: The 3 vascular patterns were differently distributed within non-RPOC as well as RPOC patients with and without PAS: type 1 vascular signal detection rates of non-RPOC and RPOC were 97.8% (262/268) and 28.1% (18/64), respectively. Of 64 cases of RPOC, 48.4% (31/64) of the patients had type 2 vascular signals. Vascular signals were enhanced in RPOC with PAS patients whose diagnosis was confirmed by histopathology. CONCLUSIONS: The vascularity (amount of flow), vascular pattern (spot, strip- or circumferential-like flow), and the flow penetrating myometrium were significant findings for distinguishing concomitant RPOC with and without PAS. Additionally, RPOC may contribute to PAS progression, or PAS and RPOC in coordination strengthen the observed vascular signals.

A bio-inspired strategy for enhanced hydrogen evolution: carbonate ions as hole vehicles to promote carrier separation.

Natural photosynthesis involves a subtle electron transfer mechanism in which freely-moving electron transfer intermediates (plastoquinone and plastocyanin) are capable of effectively separating the photo-generated carriers, and therefore, it has high quantum efficiency. Inspired by this mechanism, in this study, carbonate (CO32-) ions were employed as hole vehicles to promote photo-generated carrier separation, and greatly improved the photocatalytic hydrogen evolution activity of K4Nb6O17 nanosheets. The hydrogen evolution rate at the optimal concentration of CO32- ions reached 2018 µmol h-1 g-1, which was 16.3 times that of the blank sample (124 µmol h-1 g-1). This marked enhancement was based on the transfer of holes from the photocatalyst to the sacrificial reagent (methanol) via CO32- ions; this process is faster than direct hole transfer between the photocatalyst and sacrificial reagent. This bio-inspired strategy provides a facile and cost-effective approach to improve the solar-to-fuel conversion efficiency of photocatalysts.

Enhanced hydrogen evolution from water splitting based on ZnO nanosheet/CdS nanoparticle heterostructures.

As environmental and energy problems have worsened worldwide, research for developing renewable energy has become urgent. Presently, the primary focus of such research is directed towards the photocatalytic decomposition of water to produce hydrogen as an energy source. Herein, ZnO nanosheet/CdS nanoparticle heterostructures were synthesized by a mild wet chemical reaction and displayed a high photocatalytic efficiency (1040 µmol g-1 h-1) without Pt loading under visible light radiation. The structure was prepared by first constructing two-dimensional nanocrystalline ZnO flowers and then loading CdS nanoparticles onto the nanocrystals. Results show that this structure can facilitate the separation of photogenerated electrons and holes and improve the photocatalytic efficiency and stability of the materials in the photocatalytic decomposition of water. By changing different experimental conditions to prepare a variety of samples and test their properties, we can analyze the optimal parameters for the preparation of this material.

Photorechargeable High Voltage Redox Battery Enabled by Ta3 N5 and GaN/Si Dual-Photoelectrode.

Solar rechargeable battery combines the advantages of photoelectrochemical devices and batteries and has emerged as an attractive alternative to artificial photosynthesis for large-scale solar energy harvesting and storage. Due to the low photovoltages by the photoelectrodes, however, most previous demonstrations of unassisted photocharge have been realized on systems with low open circuit potentials (<0.8 V). In response to this critical challenge, here it is shown that the combined photovoltages exceeding 1.4 V can be obtained using a Ta3 N5 nanotube photoanode and a GaN nanowire/Si photocathode with high photocurrents (>5 mA cm-2 ). The photoelectrode system makes it possible to operate a 1.2 V alkaline anthraquinone/ferrocyanide redox battery with a high ideal solar-to-chemical conversion efficiency of 3.0% without externally applied potentials. Importantly, the photocharged battery is successfully discharged with a high voltage output.

Assembly of Ag3PO4 nanoparticles on two-dimensional Ag2S sheets as visible-light-driven photocatalysts.

Ag3PO4 has been proven to be a promising catalyst with superior activity compared to other existing visible-light-driven photocatalysts. In this work, Ag3PO4 nanoparticles were deposited on the surface of two-dimensional Ag2S sheets by an in situ synthesis strategy. The microstructure, composition, and performance of the resulting Ag3PO4/Ag2S composites could be tailored by surface-functioned Ag2S sheets. The composite reached optimum performance when the molar ratio of Ag2S to Ag3PO4 was 0.31, showing a 2-fold enhancement in the degradation rate in comparison to pure Ag3PO4. Efficient separation of photogenerated electron-hole pairs was achieved through a Z-scheme system in which Ag particles served as the center for the combination of electrons at the conduction band of Ag3PO4 and holes at the valence band of Ag2S. In addition to the matched band structure of Ag2S and Ag3PO4, the monodispersed Ag3PO4 nanoparticles were efficient in light harvesting due to the presence of Ag2S. The advantageous interface effect produced by Ag2S sheets and nano-sized Ag3PO4 nanoparticles also contributed to the improvement in photocatalytic activity.

Ag(I)-bovine serum albumin hydrosol-mediated formation of Ag3PO4/reduced graphene oxide composites for visible-light degradation of Rhodamine B solution.

A cost-effective Ag(I)-bovine serum albumin (BSA) supramolecular hydrosol strategy was utilized to assemble Ag3PO4 nanospheres onto reduced graphene oxide (rGO) sheets. The obtained composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy. Compared with the pure Ag3PO4 crystals and Ag3PO4 particles prepared with Ag(I)-BSA hydrosol as precursor, the Ag3PO4/rGO composites obtained with different content of graphene oxide indicated improved visible-light-driven photocatalysis activity for the decomposition of Rhodamine B aqueous solution. The results pointed to the possibility of synthesizing graphene-based photocatalysts by metal ion-BSA hydrosol.