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Topic Review
Zeolitic Imidazolate Framework
Zeolitic imidazolate frameworks (ZIFs) are a class of metal-organic frameworks that are topologically isomorphic with zeolites. ZIFs are composed of tetrahedrally-coordinated transition metal ions (e.g. Fe, Co, Cu, Zn) connected by imidazolate linkers. Since the metal-imidazole-metal angle is similar to the 145° Si-O-Si angle in zeolites, ZIFs have zeolite-like topologies. As of 2010, 105 ZIF topologies have been reported in the literature. Due to their robust porosity, resistance to thermal changes, and chemical stability, ZIF’s are being investigated for applications such as carbon capture.
  • 1.2K
  • 25 Oct 2022
Topic Review
Zeolite/Pharmaceuticals System
Zeolites belong to aluminosilicate microporous solids, with strong and diverse catalytic activity, which makes them applicable in almost every kind of industrial process, particularly thanks to their eco-friendly profile. Another crucial characteristic of zeolites is their tremendous adsorption capability. Therefore, it is self-evident that the widespread use of zeolites is in environmental protection, based primarily on the adsorption capacity of substances potentially harmful to the environment, such as pharmaceuticals, pesticides, or other industry pollutants. On the other hand, zeolites are also recognized as drug delivery systems (DDS) carriers for numerous pharmacologically active agents. The enhanced bioactive ability of DDS zeolite as a drug carrying nanoplatform is confirmed, making this system more specific and efficient, compared to the drug itself. These two applications of zeolite, in fact, illustrate the importance of (ir)reversibility of the adsorption process. 
  • 940
  • 11 Aug 2022
Topic Review
Zeolite Synthesis and the Crystallization Process
Zeolites, as a class of crystalline minerals, find a wide range of applications in various fields, such as catalysis, separation, and adsorption. These materials have also been developed for advanced applications, such as gas storage, medical applications, magnetic adsorption, and zeolitic-polymeric membranes. To effectively design zeolites for such intriguing applications, it is crucial to intelligently adjust their crystal size, morphology, and defect population in relation to crystal perfection. Optimizing these fundamental parameters necessitates a deep understanding of zeolite formation mechanisms, encompassing the thermodynamics and kinetics of nucleation steps as well as crystallite growth. 
  • 193
  • 31 Jul 2023
Topic Review
Zearalenone and the Immune Response
Zearalenone (ZEA) is an estrogenic fusariotoxin, being classified as a phytoestrogen, or as a mycoestrogen. ZEA and its metabolites are able to bind to estrogen receptors, 17β-estradiol specific receptors, leading to reproductive disorders which include low fertility, abnormal fetal development, reduced litter size and modification at the level of reproductive hormones especially in female pigs. ZEA has also significant effects on immune response with immunostimulatory or immunosuppressive results. This review presents the effects of ZEA and its derivatives on all levels of the immune response such as innate immunity with its principal component inflammatory response as well as the acquired immunity with two components, humoral and cellular immune response. The mechanisms involved by ZEA in triggering its effects are addressed. 
  • 531
  • 26 Apr 2021
Topic Review
Yucca Saponins. Bioactivity and analytical methods
Yucca is one of the main sources of steroidal saponins, hence different extracts are commercialized for use as surfactant additives by beverage, animal feed, cosmetics or agricultural products. For a deeper understanding of the potential of the saponins that can be found in this genus, an exhaustive review of the structural characteristics, bioactivities and analytical methods that can be used with these compounds has been carried out, since there are no recent reviews on the matter. Thus, a total of 108 saponins from eight species of the genus Yucca have been described.
  • 642
  • 08 Oct 2021
Topic Review
Ytterbium Fluoride in Dental Materials
The compound ytterbium trifluoride is used as a component of several dental materials. Ytterbium trifluoride is reported to be insoluble in water. Despite this, its presence is associated with fluoride release from dental materials. There is evidence that it reacts with the components of calcium trisilicate cements to form small amounts of a variety of compounds, including ytterbium oxide, Yb2O3, and calcium–ytterbium fluoride, CaYbF5. In nanoparticulate form, it has been shown to reinforce glass polyalkenoates and it also provides high contrast in X-ray images.
  • 157
  • 12 Jan 2024
Topic Review
Yeast Particles Encapsulation Methods for Terpene Release Duration
Terpenes and essential oils are materials of great commercial use due to their broad spectra of antibacterial, antifungal, membrane permeation enhancement and antioxidant biological properties, as well as for their use as flavors and fragrances. Yeast particles (YPs) are 3–5 µm hollow and porous microspheres, a byproduct of some food-grade yeast (Saccharomyces cerevisiae) extract manufacturing processes, that have been used for the encapsulation of terpenes and essential oils with high payload loading capacity (up to 500% weight) and efficiency, providing stability and sustained-release properties. 
  • 277
  • 12 Jun 2023
Topic Review
Xylosma G. Forst. Genus
Xylosma G. Forst. is a genus of plants belonging to the Salicaceae family with intertropical distribution in America, Asia, and Oceania. Of the 100 accepted species, 22 are under some level of conservation risk. Around 13 species of the genus used as medicinal plants were found, mainly in Central and South America, with a variety of uses, among which antimicrobial is the most common.
  • 525
  • 18 May 2022
Topic Review
Xylose Metabolism in Bacteria
Some wild-type and genetically modified bacteria can metabolize xylose through three different main pathways of metabolism: xylose isomerase pathway, oxidoreductase pathway, and non-phosphorylative pathway (including Weimberg and Dahms pathways). Two of the commercially interesting intermediates of these pathways are xylitol and xylonic acid, which can accumulate in the medium either through manipulation of the culture conditions or through genetic modification of the bacteria. 
  • 700
  • 28 Sep 2021
Topic Review
XPS Study Calcining Mixtures of Brucite with Titania
The X-ray stimulation photospectrometry technique known as XPS is applied to determine chemical bond characteristics of organic and inorganic substances. On the other hand, the processes of chemical substance formation can be energetically activated by various mechanisms, one of them being thermal activation. Magnesium oxide (magnesia, MgO) and titanium oxide (titania, TiO2) are substances that, due to their chemical and energetic nature, can chemically react to form other chemical compounds when subjected to relatively high temperatures. During the sintering of MgO it is feasible to use some additives such as TiO2 to improve some properties, but during the process it is possible the formation of substances that limit its final application at high temperature. This review focuses on the relatively high-temperature synthesis and characterization of compounds based on MgO:TiO2 in a 50:50 wt% ratio, using the XPS technique and supported by XRD.
  • 1.1K
  • 22 Mar 2022
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