Solar generation and storage of O2 (a 1 delta g)

An investigation was performed of the technical steps required to design a solar powered oxygen-iodine laser. Singlet delta oxygen is formed upon transfer of energy from selected photoexcited dye molecules to ground state molecular oxygen and then is concentrated and stored as an endoperoxide by reaction with an aromatic hydrocarbon. The endoperoxide, when heated, releases singlet oxygen in high yield thus providing a regenerable source of laser fuel. Energy transfer from dye molecules to molecular oxygen was investigated. When dye molecules were adsorbed to polymer substrates it was observed that the dye became embedded in the polymer matrix. Porphin dyes were incorporated into films of 1,4-dimethyl-2-poly(vinylnaphthalene), 2PVN. An endoperoxide was formed when porphin-doped 2PVN was exposed to visible radiation. This demonstrates the possibility of generating singlet oxygen using solar energy and concentrating and storing it in one simple step. Transport of energy by exciton migration in polycrystalline dye films was also investigated

Thymol as a Component of Chitosan Systems—Several New Applications in Medicine: A Comprehensive Review

Thymol, a plant-derived monoterpene phenol known for its broad biological activity, has often been incorporated into chitosan-based biomaterials to enhance therapeutic efficacy. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, we conducted a systematic literature review from 2018 to 2023, focusing on the biomedical implications of thymol-loaded chitosan systems. A review of databases, including PubMed, Scopus, and Web of Science was conducted using specific keywords and search criteria. Of the 90 articles, 12 were selected for the review. Thymol-loaded chitosan-based nanogels (TLCBS) showed improved antimicrobial properties, especially against multidrug-resistant bacterial antagonists. Innovations such as bipolymer nanocarriers and thymol impregnated with photosensitive chitosan micelles offer advanced bactericidal strategies and show potential for bone tissue regeneration and wound healing. The incorporation of thymol also improved drug delivery efficiency and biomechanical strength, especially when combined with poly(dimethylsiloxane) in chitosan–gelatin films. Thymol–chitosan combinations have also shown promising applications in oral delivery and periodontal treatment. This review highlights the synergy between thymol and chitosan in these products, which greatly enhances their therapeutic efficacy and highlights the novel use of essential oil components. It also highlights the novelty of the studies conducted, as well as their limitations and possible directions for the development of integrated substances of plant and animal origin in modern and advanced medical applications

The Superconducting TESLA Cavities

The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. The design goal for the cavities of the TESLA Test Facility (TTF) linac was set to the more moderate value of Eacc >= 15 MV/m. In a first series of 27 industrially produced TTF cavities the average gradient at Q0 = 5E+9 was measured to be 20.1 +- 6.2 MV/m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities additional quality control measures were introduced, in particular an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electron-beam welds. The average gradient of these cavities at Q0 = 5E+9 amounts to 25.0 +- 3.2 MV/m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing R&D towards higher gradients is briefly addressed.Comment: 45 pages (Latex), 39 figures (Encapsulated Postscript), 53 Author

Scientific rationale for Uranus and Neptune <i>in situ</i> explorations

The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission