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Topic Review
Gas Chromatography - Vacuum Ultraviolet Spectroscopy (GC-VUV)
Gas Chromatography - Vacuum Ultraviolet (GC-VUV) spectroscopy is a universal detection platform for gas chromatography. The first benchtop detector was introduced in 2014 with detection capabilities between 120 - 240 nm. This portion of the ultraviolet spectrum had historically been restricted to bright source synchrotron facilities due to significant background absorption challenges inherent to working within the wavelength range. Further detector platform development has extended the wavelength detection range out from 120 - 430 nm. VUV detection provides both qualitative and quantitative spectral information for most gas phase compounds. GC-VUV spectral data is three dimensional (time, absorbance, wavelength) and specific to chemical structure. Nearly all compounds absorb in the VUV region of the electromagnetic spectrum with the exception of carrier gases hydrogen, helium, and argon. The high energy, short wavelength VUV photons probe electronic transitions in almost all chemical bonds including ground state to excited state. The result is spectral "fingerprints" that are specific to individual compound structure and can be readily identified by the VUV library. Unique VUV spectra enable closely related compounds such as structural isomers to be clearly differentiated. VUV detectors complement mass spectrometry, which struggles with characterizing constitutional isomers and compounds with low mass quantitation ions. VUV spectra can also be used to deconvolve analyte co-elution, resulting in an accurate quantitative representation of individual analyte contribution to the original response. This characteristically lends itself to significantly reducing GC runtimes through flow rate-enhanced chromatographic compression. VUV spectroscopy follows the simple linear relationship between absorbance and concentration described by the Beer-Lambert Law resulting in more accurate retention time-based identification. VUV absorbance spectra also exhibit feature similarity within compound classes, meaning VUV detectors can rapidly compound class characterization in complex samples through compound spectral shape and retention index information. Advances in technology reduces the typical group analysis data processing time from 15-30 minutes to <1 minute per sample.
  • 3.4K
  • 17 Nov 2022
Topic Review
NATURAL CLINOPTILOLITE CHARACTERIZATION BY SEM
Clinoptilolite is the most common natural zeolite type. Owing to the very convenient Si/Al ratio, which characterizes this type of zeolite, it can be used for the fabrication of impedimetric water sensors, useful for example for breath rate mesurament and development of low-cost spirometers. The clinoptilolite adsorption properties are related to the large surface development due to the mesoporous structure. The clinoptilolite mesoporosity is a consequence of the unique lamellar texture of this mineral. The clinoptilolite lamellar texture cannot be observed by microscopical techniques like optical microscopy (OM) and scanning electron microscopy (SEM) without adequate sample preparation. Here, a very simple approach to delaminate the clinoptilolite mineral, based on the application of an impulsed compressive stress (hammer), has been used to separate the clinoptilolite single crystals and scanning electron microscopy has been used to visualize and to measure the clinoptilolite crystals.
  • 3.4K
  • 05 Jul 2021
Topic Review Peer Reviewed
Foundations of Quantum Mechanics
Quantum mechanics is a mathematical formalism that models the dynamics of physical objects. It deals with the elementary constituents of matter (atoms, subatomic and elementary particles) and of radiation. It is very accurate in predicting observable physical phenomena, but has many puzzling properties. The foundations of quantum mechanics are a domain in which physics and philosophy concur in attempting to find a fundamental physical theory that explains the puzzling features of quantum mechanics, while remaining consistent with its mathematical formalism. Several theories have been proposed for different interpretations of quantum mechanics. However, there is no consensus regarding any of these theories.
  • 3.4K
  • 07 Jun 2022
Topic Review
Purple Drank
Purple drank is a recreational drug, created by combining prescription-grade cough syrup with a soft drink and hard candy. The concoction originated in Houston, Texas, and is popular among those who belong to the hip hop subculture or reside in the southern United States.
  • 3.4K
  • 02 Nov 2022
Topic Review
Architecture of Dima System
One of the most recent manifestations of avionics system is Distributed Integrated Modular Avionics (DIMA).  The study of DIMA architecture is essential when considering two levels of mappings, that is (1) software modules to hardware components, and (2) hardware components to installation locations. This entry describes the hierarchical design of DIMA, including system layer, hardware layer and installation layer that are linked with a group of constraints and quality measures.
  • 3.4K
  • 26 Apr 2020
Topic Review
SO2 Poisoning Mechanism
The selective catalytic reduction (SCR) has been widely used in industrial denitrification owing to its high denitrification efficiency, low operating costs, and simple operating procedures. However, coal containing a large amount of sulfur will produce SO2 during combustion, which makes the catalyst easy to be deactivated, thus limiting the application of this technology. This review summarizes the latest NH3-SCR reaction mechanisms and the deactivation mechanism of catalyst in SO2-containing flue gas. Some strategies are summarized for enhancing the poison-resistance through modification, improvement of support, the preparation of complex oxide catalyst, optimizing the preparation methods, and acidification. The mechanism of improving sulfur resistance of catalysts at low temperatures is summarized, and the further development of the catalyst is also prospected. This paper could provide a reference and guidance for the development of SO2 resistance of the catalyst at low temperatures.
  • 3.4K
  • 09 Nov 2020
Topic Review
Skeletal Muscle Myokines
The skeletal muscle is the largest organ in the body and secretes circulating factors, including myokines, which are involved in various cellular signaling processes. Skeletal muscle is vital for metabolism and physiology and plays a crucial role in insulin-mediated glucose disposal. Myokines have autocrine, paracrine, and endocrine functions, serving as critical regulators of myogenic differentiation, fiber-type switching, and maintaining muscle mass. Myokines have profound effects on energy metabolism and inflammation, contributing to the pathophysiology of type 2 diabetes (T2D) and other metabolic diseases. Myokines have been shown to increase insulin sensitivity, thereby improving glucose disposal and regulating glucose and lipid metabolism. 
  • 3.4K
  • 05 May 2022
Topic Review
Microalgae-Based Biorefineries: Challenges and Future Trends
Microalgae-based biorefineries allow the simultaneous production of microalgae biomass enriched in a particular macromolecule and high-added and low-value products if a proper selection of the microalgae species and the cultivation conditions are adequate for the purpose. 
  • 3.4K
  • 30 Aug 2022
Topic Review
Flashline Mars Arctic Research Station
The Flashline Mars Arctic Research Station (FMARS) is the first of two simulated Mars habitats (or Mars Analog Research Stations) established and maintained by the Mars Society.
  • 3.4K
  • 10 Oct 2022
Topic Review
VC Dimension
In Vapnik–Chervonenkis theory, the VC dimension (for Vapnik–Chervonenkis dimension) is a measure of the capacity (complexity, expressive power, richness, or flexibility) of a space of functions that can be learned by a statistical classification algorithm. It is defined as the cardinality of the largest set of points that the algorithm can shatter. It was originally defined by Vladimir Vapnik and Alexey Chervonenkis. Formally, the capacity of a classification model is related to how complicated it can be. For example, consider the thresholding of a high-degree polynomial: if the polynomial evaluates above zero, that point is classified as positive, otherwise as negative. A high-degree polynomial can be wiggly, so it can fit a given set of training points well. But one can expect that the classifier will make errors on other points, because it is too wiggly. Such a polynomial has a high capacity. A much simpler alternative is to threshold a linear function. This function may not fit the training set well, because it has a low capacity. This notion of capacity is made rigorous below.
  • 3.4K
  • 04 Nov 2022
Topic Review
Digital Hydraulic Technology
The digital hydraulic technology as a system which controls a discrete fluid with a modulated, discrete, digital signal directly to realize active and intelligent control of the system output. The hydraulic components with such technical characteristics can be defined as digital hydraulic components. The system composed by digital hydraulic components can also be defined as digital hydraulic system. What is more, the essential feature of digital hydraulic technology is intelligent control; technology which can only realize on/off control cannot be classified as digital hydraulic technology.
  • 3.4K
  • 05 May 2022
Topic Review
Native Plants from Mexico Used in Herbal Products
Historically, herbal products were the first resource used by man for the improvement of his health. It is the knowledge of these products that perpetuated medicinal practices prevail today as well. Mexico ranks fifth among megadiverse countries as it is home to nearly 23,424 vascular plants, which represent 5000 endemic plant species; of these, a total of 4500 medicinal plants have been estimated, while only 3000 are registered in the herbarium of the Mexican Institute of Social Security (IMSS). However, a pharmacological analysis of only 5% has been reported. The country boasts a wide range of medicine made from plants that are representative of traditional Mexican herbal products. There has been a steady rise in the use and commercialization of herbal products, demonstrative of the increase in world demand in this industry. Further, 90% of the population in Mexico has opted for these products at least once in their lives, as indicated by the Secretaría de Salud (SS) and Comisión Federal para la Protección contra Riesgos Sanitarios (COFEPRIS).
  • 3.4K
  • 20 May 2022
Topic Review
Cereal–Legume Intercropping
With the current objective of moving away from monoculture and the development of the "ecological intensification" of agrosystems, the cereal-legume intercropping takes advantage of the symbiotic relationships that the legume develops with soil micro-organisms (rhizobiums). Legumes are capable of fixing atmospheric nitrogen thanks to the nodules of its roots, and thus provide to this crop a part of its nitrogen needs. The choice of species and the proportion of grains to be sown are determined by the objectives of intercropping. For human food, simple mixtures are favoured (e.g. wheat/pea, barley/bean, triticale/pea). For fodder production, the number of species can be higher.
  • 3.4K
  • 27 Oct 2020
Topic Review
Interplay between Polyphenols and Lysyl Oxidase Enzymes
Collagen, the most abundant structural protein found in mammals, plays a vital role as a constituent of the extracellular matrix (ECM) that surrounds cells. Collagen fibrils are strengthened through the formation of covalent cross-links, which involve complex enzymatic and non-enzymatic reactions. Lysyl oxidase (LOX) is responsible for catalyzing the oxidative deamination of lysine and hydroxylysine residues, resulting in the production of aldehydes, allysine and hydroxyallysine. These intermediates undergo spontaneous condensation reactions, leading to the formation of immature cross-links, which are the initial step in the development of mature covalent cross-links. Additionally, non-enzymatic glycation contributes to the formation of abnormal cross-linking in collagen fibrils. During glycation, specific lysine and arginine residues in collagen are modified by reducing sugars, leading to the creation of Advanced Glycation End-products (AGEs). These AGEs have been associated with changes in the mechanical properties of collagen fibers.
  • 3.4K
  • 13 Jul 2023
Topic Review
Polytetrafluoroethylene-Based Solvent-Free Procedure for Lithium-Ion Batteries Manufacturing
Lithium-ion batteries (LIBs) have become popular for energy storage due to their high energy density, storage capacity, and long-term cycle life. Although binders make up only a small proportion of LIBs, they have become the key to promoting the transformation of the battery preparation process. Along with the development of binders, the battery manufacturing process has evolved from the conventional slurry-casting (SC) process to a more attractive solvent-free (SF) method. Compared with traditional LIBs manufacturing method, the SF method could dramatically reduce and increase the energy density due to the reduced preparation steps and enhanced electrode loading. Polytetrafluoroethylene (PTFE), as a typical binder, has played an important role in fabricating high-performance LIBs, particularly in regards to the SF technique. 
  • 3.4K
  • 15 Dec 2023
Topic Review
Vitamin D Metabolism Gene Polymorphisms
Vitamin D is a potent immunonutrient that through its main metabolite calcitriol, regulates the immunomodulation of macrophages, dendritic cells, T and B lymphocytes, which express the vitamin D receptor (VDR), and they produce and respond to calcitriol. Genetic association studies have shown that up to 65% of vitamin D serum variance may be explained due to genetic background. 
  • 3.4K
  • 02 Jan 2022
Topic Review
Green Supply Chain Management
Green or sustainable supply chain management (SSCM) involves integrating environmental and economic objectives into the management of the operation strategy of the supply chain. Such integration helps reduce the carbon footprint while increasing financial return and profitability. A wider concept is SSCM, which aims to maximize profitability and, at the same time, reduce the environmental impact and improve the social well-being of the various involved stakeholders.
  • 3.4K
  • 30 Jul 2021
Topic Review
Roman Engineering
The ancient Romans were famous for their advanced engineering accomplishments, although some of their inventions were improvements on older ideas, concepts and inventions. Technology for bringing running water into cities was developed in the east, but transformed by the Romans into a technology inconceivable in Greece. The architecture used in Rome was strongly influenced by Greek and Etruscan sources. Roads were common at that time, but the Romans improved their design and perfected the construction to the extent that many of their roads are still in use today. Their accomplishments surpassed most other civilizations of their time, and after their time, and many of their structures have withstood the test of time to inspire others, especially during the Renaissance. Moreover, their contributions were described in some detail by authors such as Vitruvius, Frontinus and Pliny the Elder, so there is a printed record of their many inventions and achievements.
  • 3.4K
  • 27 Oct 2022
Biography
Grigore Rosu
Grigore Roșu is a computer science professor at the University of Illinois at Urbana-Champaign and a researcher in the Information Trust Institute.[1] He is known for his contributions in runtime verification, K framework,[2] matching logic,[3] and automated coinduction.[4] Rosu received a B.A. in Mathematics in 1995 and an M.S. in Fundamentals of Computing in 1996, both from the University
  • 3.4K
  • 06 Dec 2022
Topic Review
Industrial Hemp
Hemp is a type of Cannabis sativa plant and has multiple applications in food, construction, pharmaceuticals, and materials. Hemp was used in fabrics, twine, and paper products in the 1800s and 1900s; however, its production and applications were regulated with the Marijuana Tax Act in 1937 and the Controlled Substances Act in 1970 by the US Congress. In the 2014 Farm Bill, the US Congress defined industrial hemp depending on the level of THC (less than 0.3% THC on a dry weight basis) and allowed its agricultural pilot program by research institution and department of agriculture if the state laws allow.
  • 3.4K
  • 25 Feb 2021
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