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Topic Review
Proton Exchange Membrane Fuel Cells
Proton exchange membrane fuel cells (PEMFCs) operate by converting the chemical energy in a fuel into electrical energy. The most crucial parameters in the operation process are the temperature, pressure, relative humidity, and air stoichiometry ratio. The classical structure of a PEMFC consists of a proton exchange membrane, anode electrode, cathode electrode, catalyst layers (CLs), microporous layer (MPLs), gas diffusion layers (GDLs), two bipolar plates (BPs), and gas flow channels (GFCs). The mechanical behavior and the conductivity of the protons are highly dependent on the structure of the MEAs.
  • 3.4K
  • 20 Feb 2023
Topic Review
SOCH: The Mental Colonization Of India
India is a land of immense plurality, rich cultural heritage, and multiple forms of colonization since centuries. Though the physical colonization by the British ended in 1947, the mental colonization persists through several socio-economic and cultural mechanisms. This article discusses the concept of mental colonization in India, termed as "SOCH" (Spirit of Colonial Hangover), its historical roots, contemporary manifestations, and its struggle to seek and acquire indigenous identities and histories.
  • 3.4K
  • 31 Oct 2024
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
Stock-Flow Consistent Model
Stock-Flow Consistent (SFC) models are a family of macroeconomic models based on a rigorous accounting framework, which guarantees a correct and comprehensive integration of all the flows and the stocks of an economy. These models were first developed in the mid-20th century but have recently become popular, particularly within the post-Keynesian school of thought.
  • 3.4K
  • 19 Oct 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
Topic Review
Analysis of Minimum Inhibitory Concentrations
In response to the threat presented by AMR, it is critically important to find methods for effectively interpreting minimum inhibitory concentration (MIC) tests. A wide array of techniques for analysis of MIC data exist, which require different ways of modifying the MIC data for use as the dependent variable in regression and analysis. For use as the outcome in logistic regression, MIC data is categorized using clinical breakpoints and epidemiological cutoff values (ECOFF). Clinical breakpoints classify isolates as susceptible (S), resistant (R), or an intermediate category based on expected clinical outcomes of treatment with a specific antimicrobial. The ECOFF classifies organisms as wild type (WT) or non-wild type (non-WT)  based on the absence or presence of phenotypically-detectable acquired resistance mechanisms to the specific antimicrobial. Dichotomization of MIC data results in information loss, as only changes in the proportions of WT/non-WT or S/R are observed in dichotomized data. As a result, changes in MIC distributions that do not cross the threshold may be unobserved using approaches with dichotomized outcomes. Other modeling approaches for MIC data may attempt to avoid information loss by not dichotomizing the outcome when using regression to analyze MIC data.
  • 3.4K
  • 02 Sep 2020
Topic Review
Chemical File Format
A chemical file format is a type of data file which is used specifically to depicting molecular data. One of the most widely used is the chemical table file format, which is similar to Structure Data Format (SDF) files. They are text files that represent multiple chemical structure records and associated data fields. The XYZ file format is a simple format that usually gives the number of atoms in the first line, a comment on the second, followed by a number of lines with atomic symbols (or atomic numbers) and cartesian coordinates. The Protein Data Bank Format is commonly used for proteins but is also used for other types of molecules. There are many other types which are detailed below. Various software systems are available to convert from one format to another.
  • 3.4K
  • 25 Oct 2022
Topic Review
Spawn
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, to spawn refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs. Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mosquitoes and corals, which are actually small aquatic animals—not plants. Fungi, such as mushrooms, are also said to "spawn" a white, fibrous matter that forms the matrix from which they grow. There are many variations in the way spawning occurs, depending on sexual differences in anatomy, how the sexes relate to each other, where and how the spawn is released and whether or how the spawn is subsequently guarded.
  • 3.4K
  • 08 Nov 2022
Topic Review
Cynicism
Cynicism (Ancient Greek:) is a school of thought of ancient Greek philosophy as practiced by the Cynics (Ancient Greek:; Latin: Cynici). For the Cynics, the purpose of life is to live in virtue, in agreement with nature. As reasoning creatures, people can gain happiness by rigorous training and by living in a way which is natural for themselves, rejecting all conventional desires for wealth, power, and fame, and even flouting conventions openly and derisively in public. Instead, they were to lead a simple life free from all possessions. The first philosopher to outline these themes was Antisthenes, who had been a pupil of Socrates in the late 400 BC. He was followed by Diogenes, who lived in a ceramic jar on the streets of Athens. Diogenes took Cynicism to its logical extremes, and came to be seen as the archetypal Cynic philosopher. He was followed by Crates of Thebes, who gave away a large fortune so he could live a life of Cynic poverty in Athens. Cynicism gradually declined in importance after the 3rd century BC, but it experienced a revival with the rise of the Roman Empire in the 1st century. Cynics could be found begging and preaching throughout the cities of the empire, and similar ascetic and rhetorical ideas appeared in early Christianity. By the 19th century, emphasis on the negative aspects of Cynic philosophy led to the modern understanding of cynicism to mean a disposition of disbelief in the sincerity or goodness of human motives and actions.
  • 3.4K
  • 24 Oct 2022
Topic Review
Commercially Important Chlorinated Phenols
Phenols are compounds having a hydroxyl group attached to an aromatic ring such as a benzene or naphthalene ring. Several phenols that also possess one or more chlorine substituents attached to the aromatic ring have significant commercial importance, and these are the subject of this entry.
  • 3.4K
  • 08 Jan 2022
Topic Review
Fluid and Crystallized Intelligence
The concepts of fluid intelligence (gf) and crystallized intelligence (gc) were introduced in 1963 by the psychologist Raymond Cattell. According to Cattell's psychometrically-based theory, general intelligence (g) is subdivided into gf and gc. Fluid intelligence is the ability to solve novel reasoning problems and is correlated with a number of important skills such as comprehension, problem solving, and learning. Crystallized intelligence, on the other hand, involves the ability to deduce secondary relational abstractions by applying previously learned primary relational abstractions.
  • 3.4K
  • 18 Nov 2022
Topic Review
Cell
The cell (from the Latin word cellula meaning 'small room') is the basic structural and functional unit of life forms. Every cell consists of a cytoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids. Cells can acquire specified function and carry out various tasks within the cell such as replication, DNA repair, protein synthesis, and motility. Cells are capable of specialization and mobility within the cell. Most cells are measured in micrometers due to their small size. Most plant and animal cells are only visible under a light microscope, with dimensions between 1 and 100 micrometres. Electron microscopy gives a much higher resolution showing greatly detailed cell structure. Organisms can be classified as unicellular (consisting of a single cell such as bacteria) or multicellular (including plants and animals). Most unicellular organisms are classed as microorganisms. The number of cells in plants and animals varies from species to species; it has been approximated that the human body contains an estimated 37 trillion (3.72×1013) cells. The brain accounts for around 80 billion of these cells. The study of cells and how they work has led to many other studies in related areas of biology, including: discovery of DNA, cancer systems biology, aging and developmental biology. Cell biology is the study of cells, which were discovered by Robert Hooke in 1665, who named them for their resemblance to cells inhabited by Christian monks in a monastery. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells. Cells emerged on Earth about 4 billion years ago.
  • 3.4K
  • 23 Nov 2022
Topic Review
Urban Land Management during 1979-2021
As the carrier of global urbanization, urban land is the basic means of productivity and life of urban residents. Urban land management is of great significance to global climate change mitigation, improving ecological quality, promoting economic development, and ensuring sustainable urban development. Although studies on urban land management have accumulated at the global level, the differences in research methods, objectives, and perspectives have led to the fragmentation and confusion of research conclusions. Combined with the annual change trend of scientific research output, urban land management research can be divided into three stages: the budding period, from 1979 to 1989, the development period, from 1990 to 2008, and the high-yield period, from 2009 to 2021. 
  • 3.4K
  • 11 Nov 2022
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
Mobile Launcher Platform
A mobile launcher platform, also known as mobile launch platform, is a steel structure used to support a large multistage space vehicle which is assembled (stacked) vertically in an integration facility (e.g. the Vehicle Assembly Building) and then transported by a crawler-transporter (CT) to a launch pad. This becomes the support structure for launch. Alternatives to this method include horizontal assembly and transport to the pad, as used by Russia; and assembling the vehicle vertically on the launch pad, as the United States used for smaller launch vehicles. The use of mobile launcher platforms dates back to the "Integrate-Transfer-Launch" (ITL) concept developed in 1965 for the Titan III launched from Cape Canaveral Space Launch Complex 40 and 41, and was adopted in 1966 for the Saturn V vehicle launched from Kennedy Space Center Launch Complex 39. Launch Complex 39 and 41 continue to use this concept.
  • 3.4K
  • 11 Nov 2022
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
Grinding Media in Ball Mills for Mineral Processing
The ball mill is a rotating cylindrical vessel with grinding media inside, which is responsible for breaking the ore particles. Grinding media play an important role in the comminution of mineral ores in these mills.
  • 3.4K
  • 24 Nov 2023
Topic Review
AgNPs
Elementary silver nanoparticles (AgNPs) are of great interest because of their various probable medical application. Due to their antimicrobial activity, low toxicity and inexpensive cost, the mechanism of silver nanoparticles biosynthesis in bacterial, fungal and plant cells is extremely exciting from the point of view of the different cellular compounds participation in it: proteins, enzymes, acids, etc.
  • 3.4K
  • 15 Dec 2020
Topic Review
Neurodegenerative Diseases
Neurodegenerative diseases are affecting more and more people around the world. Current therapies only treat the symptoms and not the causes of the disease. However, the pathophysiology of these diseases is now better known. In the case of Alzheimer's disease and Parkinson's disease, some common mechanisms have been identified. One of the first known mechanisms is the accumulation of proteins: α-synuclein (Parkinson's disease), Tau (Alzheimer's disease) and β-amyloid (Alzheimer's disease and Parkinson's disease) proteins. Protein accumulation is related to a disruption of mitochondrial activity associated with cell death and oxidative stress. Inflammation is also another important mechanism, which is disrupted in these pathologies.
  • 3.4K
  • 15 Sep 2023
Topic Review
Fluorescent Polymers Conspectus
The development of luminescent materials is critical to humankind. The Nobel Prizes awarded in 2008 and 2010 for research on the development of green fluorescent proteins and super-resolved fluorescence imaging are proof of this (2014). Fluorescent probes, smart polymer machines, fluorescent chemosensors, fluorescence molecular thermometers, fluorescent imaging, drug delivery carriers, and other applications make fluorescent polymers (FPs) exciting materials. 
  • 3.4K
  • 22 Mar 2022
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