Photoelectrochemical Water Splitting

To halt the buildup of carbon dioxide (CO2), the main greenhouse gas, the development of an alternative energy source to fossil fuels becomes more and more important. Hydrogen (H2) has the potential to meet the requirements as a clean non-fossil fuel in the future, if it can be produced using our primary source of energy, the sun, and stored and transported safely. The present article will give a short review on different approaches on semiconductor-based photoelectrochemical water splitting into hydrogen and oxygen (O2) using sunlight as the energy input, also generally described as photoelectrolysis

The AgCl Photoanode for Photoelectrochemical Water Splitting

Solar energy is the greatest potential source of renewable energy known to human kind and is still largely untapped. The quest to find an efficient means of converting it to a clean and storable fuel remains elusive and is the goal of artificial photosynthesis: the solar splitting of water in O2 and H2 in a man-made system. Our approach to water splitting is based on a photoelectrochemical cell with two semiconductor-liquid junctions, where AgCl acts as the photoanode for O2 production along with the photocathodic materials p-GaInP2 and a silicon solar cell for H2 production. We report light-assisted water splitting with this system, under UV/Vis illumination from aqueous solution, at good yields and without degradation of the photocatalysts

Quantum-sized silver, silver chloride and silver sulfide clusters

Thin AgCl layers photocatalytically oxidize water to O2 under appropriate conditions. The photoactivity of AgCl extends from the UV into the visible light region in a process known as self-sensitization, which is due to the formation of silver during the photoreaction. This silver can be almost quantitatively reoxidized electrochemically, making it feasible that a thin AgCl layer deposited on a conducting substrate can be used as a photoanode for water splitting if coupled with an appropriate photocathode. The silver chloride/silver cluster phase boundary plays a decisive role in the photocatalytic silver chloride electrode system. We have therefore studied this interphase by means of quantum chemical calculations from which we report first results, specifically for the (Ag)115(AgCl)192 composite. Clusters of semiconducting materials are interesting considering their application as a photocathode in such a device. In this context, we also report the synthesis and properties of luminescent quantum-sized silver sulfide clusters in the cavities of zeolite A. The color of the silver sulfide zeolite A composites ranges from colorless (low loading) to yellow–green (medium loading) to brown (high loading). A low silver sulfide content is characterized by a blue–green luminescence and distinct absorption bands, while samples with medium or high silver sulfide content show an orange or red colored emission and a continuous absorption

Creation and implantation of acellular rat renal ECM-based scaffolds

Kidney transplantation is the only potentially curative treatment for patient facing end-stage renal disease, and it is now routinely used. Its use is mainly limited by the supply of transplantable donor organs, which far exceeds the demand. Regenerative medicine and tissue engineering offer promising means for overcoming this shortage. In the present study, we developed and validated a protocol for producing acellular rat renal scaffolds. Left kidneys were removed from 26 male Lewis rats (weights: 250-350 g) and decellularized by means of aortic anterograde perfusion with ionic and anionic detergents (Triton X-100 1% and SDS 1%, respectively). 19 scaffolds thus obtained (and contralateral native kidneys as controls) were deeply characterized in order to evaluate the decellularization quality, the preservation of extracellular matrix components and resultant micro-angioarchitecture structure. The other 7 were transplanted into 7 recipient rats that had undergone unilateral nephrectomy. Recipients were sacrificed on post-transplantation day 7 and the scaffolds subjected to histologic studies. The dual-detergent protocol showed, with only 5 h of perfusion per organ, to obtain thoroughly decellularized renal scaffolds consisting almost exclusively of extracellular matrix. Finally the macro- and the microarchitecture of the renal parenchyma were well preserved, and the grafts were implanted with ease. Seven days after transplant, the scaffolds were morphologically intact although all vascular structures were obstructed with thrombi. Production and implantation of acellular rat renal scaffolds is a suitable platform for further studies on regenerative medicine and tissue engineering

Electrical storm treatment by percutaneous stellate ganglion block: the STAR study

Background and Aims An electrical storm (ES) is a clinical emergency with a paucity of established treatment options. Despite initial encouraging reports about the safety and effectiveness of percutaneous stellate ganglion block (PSGB), many questions remained unsettled and evidence from a prospective multicentre study was still lacking. For these purposes, the STAR study was designed. Methods This is a multicentre observational study enrolling patients suffering from an ES refractory to standard treatment from 1 July 2017 to 30 June 2023. The primary outcome was the reduction of treated arrhythmic events by at least 50% comparing the 12 h following PSGB with the 12 h before the procedure. STAR operators were specifically trained to both the anterior anatomical and the lateral ultrasound-guided approach. Results A total of 131 patients from 19 centres were enrolled and underwent 184 PSGBs. Patients were mainly male (83.2%) with a median age of 68 (63.8-69.2) years and a depressed left ventricular ejection fraction (25.0 +/- 12.3%). The primary outcome was reached in 92% of patients, and the median reduction of arrhythmic episodes between 12 h before and after PSGB was 100% (interquartile range -100% to -92.3%). Arrhythmic episodes requiring treatment were significantly reduced comparing 12 h before the first PSGB with 12 h after the last procedure [six (3-15.8) vs. 0 (0-1), P < .0001] and comparing 1 h before with 1 h after each procedure [2 (0-6) vs. 0 (0-0), P < .001]. One major complication occurred (0.5%). Conclusions The findings of this large, prospective, multicentre study provide evidence in favour of the effectiveness and safety of PSGB for the treatment of refractory ES