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Topic Review
Uranyl Carbonate Minerals
Uranyl carbonates are one of the largest groups of secondary uranium(VI)-bearing natural phases being represented by 40 minerals approved by the International Mineralogical Association, overtaken only by uranyl phosphates and uranyl sulfates. Uranyl carbonate phases form during the direct alteration of primary U ores on contact with groundwaters enriched by CO2, thus playing an important role in the release of U to the environment. The presence of uranyl carbonate phases has also been detected on the surface of “lavas” that were formed during the Chernobyl accident.
  • 942
  • 24 Jun 2021
Topic Review
Uranium Sulfate
Uranium sulfate (U(SO4)2) is a water-soluble salt of uranium. It is a very toxic compound. Uranium sulfate minerals commonly are widespread around uranium bearing mine sites, where they usually form during the evaporation of acid sulfate-rich mine tailings which have been leached by oxygen-bearing waters. Uranium sulfate is a transitional compound in the production of Uranium hexafluoride. It was also used to fuel aqueous Homogeneous Reactors.
  • 638
  • 28 Oct 2022
Topic Review
Uranium Mineralization of Fossil Wood
Sandstone-hosted uranium deposits commonly contain abundant organic matter, including fossil logs. The precipitation of uranium minerals is often related to reducing environments associated with these organic materials. Below the water table, uranium is likely to be precipitated as uraninite (UO2), but in drier zones a variety of uranium minerals may be found. These minerals may occur as replacements for cellular tissue, or as surface crusts or fracture fillings.
  • 1.9K
  • 28 Oct 2020
Topic Review
Ural–Altaic Languages
Ural–Altaic, Uralo-Altaic or Uraltaic is a linguistic convergence zone and former language-family proposal uniting the Uralic and the Altaic (in the narrow sense) languages. It is generally now agreed that even the Altaic languages most likely do not share a common descent: the similarities among Turkic, Mongolic and Tungusic are better explained by diffusion and borrowing. The term continues to be used for the central Eurasian typological, grammatical and lexical convergence zone. Indeed, "Ural-Altaic" may be preferable to "Altaic" in this sense. For example, J. Janhunen states that "speaking of 'Altaic' instead of 'Ural-Altaic' is a misconception, for there are no areal or typological features that are specific to 'Altaic' without Uralic." Originally suggested in the 18th century, the genealogical and racial hypotheses remained debated into the mid-20th century, often with disagreements exacerbated by pan-nationalist agendas. It had many proponents in Britain. Since the 1960s, the proposed language family has been widely rejected. A relationship between the Altaic, Indo-European and Uralic families was revived in the context of the Nostratic hypothesis, which was popular for a time, with for example Allan Bomhard treating Uralic, Altaic and Indo-European as coordinate branches. However, Nostratic too is now mostly rejected.
  • 2.4K
  • 31 Oct 2022
Topic Review
Upwelling in Marginal Seas
Upwelling refers to the upward movement of deep nutrient-rich and low-temperature waters to the surface, resulting in colder surface or near-surface waters with low dissolved oxygen, high density, and high salinity. Upwelling is economically and ecologically significant in the coastal marine system, making it high-priority research. Although representing <1% of the total surface area of the ocean, upwelling regions provide approximately 8% of the global marine primary production and more than 20% of the world’s capture fisheries. With an increase in offshore transport, strong upwelling usually transports phytoplankton and zooplankton towards the convergence offshore frontal system rapidly, relative to a weaker upwelling that limits the nutrient enrichment in the photic zone. Apart from boosting primary productivity and fishery production, upwelling is also crucial for the atmosphere-ocean carbon dioxide exchange and carbon recycling processes.
  • 510
  • 04 Aug 2023
Topic Review
Upstream Regulation in Aspergillus Species
In filamentous fungal Aspergillus species, growth, development, and secondary metabolism are genetically programmed biological processes, which require precise coordination of diverse signaling elements, transcription factors (TFs), upstream and downstream regulators, and biosynthetic genes. Regulatory roles of these controllers in asexual/sexual development and primary/secondary metabolism of Aspergillus species have been extensively studied. Among a wide spectrum of regulators, a handful of global regulators govern upstream regulation of development and metabolism by directly and/or indirectly affecting the expression of various genes including TFs.
  • 390
  • 02 Feb 2023
Topic Review
Upscaling of Carbon-Based Perovskite Solar Module
Perovskite solar cells (PSCs) and modules are driving the energy revolution in the coming photovoltaic field. PSCs reached efficiency close to the silicon photovoltaic technology by adopting low-cost solution processes. Despite this, the noble metal (such as gold and silver) used in PSCs as a counter electrode made these devices costly in terms of energy, CO2 footprint, and materials. Carbon-based perovskite solar cells (C-PSCs) and modules use graphite/carbon-black-based material as the counter electrode. The formulation of low-cost carbon-based inks and pastes makes them suitable for large area coating techniques and hence a solid technology for imminent industrialization.
  • 364
  • 19 Jan 2023
Topic Review
UPS in Human Malignancies
The ubiquitin proteasome system (UPS) governs the non-lysosomal degradation of oxidized, damaged, or misfolded proteins in eukaryotic cells. This process is tightly regulated through the activation and transfer of polyubiquitin chains to target proteins which are then recognized and degraded by the 26S proteasome complex. The role of UPS is crucial in regulating protein levels through degradation to maintain fundamental cellular processes such as growth, division, signal transduction, and stress response. Dysregulation of the UPS, resulting in loss of ability to maintain protein quality through proteolysis, is closely related to the development of various malignancies and tumorigenesis.
  • 483
  • 13 Apr 2021
Topic Review
UPS and Ca2+ Signaling
The ubiquitin–proteasome system (UPS) is the main proteolytic pathway by which damaged target proteins are degraded after ubiquitination and the recruit of ubiquitinated proteins, thus regulating diverse physiological functions and the maintenance in various tissues and cells. The UPS and Ca2+ signaling are interconnected, since each affects the other. The interconnected nature of these signals plays a critical role in regulating cellular functions. 
  • 454
  • 24 May 2022
Topic Review
Upregulation of PD-L1 Mitigates Cisplatin-Induced Acute Kidney Injury
The innate and adaptive immunities have been documented to participate in the pathogenesis of nephrotoxic acute kidney injury (AKI); however, the mechanisms controlling these processes have yet to be established. In cisplatin-induced AKI mouse model, researchers show pathological damage to the kidneys, with the classical markers elevated, consistent with the response to cisplatin treatment. Through assessments of the components of the immune system, both locally and globally, researchers demonstrate that the immune microenvironment of injured kidneys was associated with an increased infiltration of CD4+ T cells and macrophages concomitant with decreased Treg cell populations. Researchers' cell-based assays and animal studies further show that cisplatin exposure downregulated the protein levels of programmed death-ligand 1 (PD-L1), an immune checkpoint protein, in primary renal proximal tubular epithelial cells, and that these inhibitions were dose-dependent. After orthotopic delivery of PD-L1 gene into the kidneys, cisplatin-exposed mice displayed lower levels of both serum urea nitrogen and creatinine upon PD-L1 expression. Researchers data suggest a renoprotective effect of the immune checkpoint protein, and thereby provide a novel therapeutic strategy for cisplatin-induced AKI.
  • 549
  • 16 Dec 2021
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