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The Foundation of Classical Mechanics
Mechanics is the science of the equilibrium and motion of bodies subject to forces. The adjective classical, hence Classical Mechanics , was added in the 20th century to distinguish it from relativistic mechanics which studies motion with speed close to light speed and quantum mechanics which studies motion at a subatomic level.
  • 2.7K
  • 13 Apr 2022
Topic Review
Zone Refining
Zone refining is a technology of deeply purifying metals. Its essence is to use the difference in solubility of impurity elements in the solid and molten state of the main metal to precipitate the impurities or change the distribution of the impurity elements. It provides an effective and easy method for preparing high-purity metals. 
  • 2.7K
  • 18 May 2021
Topic Review
Point-Of-Care or Point-Of-Need Diagnostic Tests
In the recent years, the progress of international trade and travel has led to an increased risk of emerging infections. Around 75 percent of the pathogens causing these infections are of animal origin. Point-of-care tests (POCT) and point-of-need tests (PONT) have been established in order to directly provide accurate and rapid diagnostics at field level, the patient bed-side or at the site of outbreaks. These assays can help physicians and decision makers to take the right action without delay. Typically, POCT and PONT rely on genomic identification of pathogens or track their immunological fingerprint. Recently, protocols for metagenomic diagnostics in the field have been developed.
  • 2.7K
  • 20 Apr 2021
Topic Review
Beta-Carotene
β-Carotene is an organic, strongly coloured red-orange pigment abundant in fungi, plants, and fruits. It is a member of the carotenes, which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons. Among the carotenes, β-carotene is distinguished by having beta-rings at both ends of the molecule. β-Carotene is biosynthesized from geranylgeranyl pyrophosphate. In some Mucoralean fungi, β-Carotene is a precursor to the synthesis of trisporic acid. β-Carotene is the most common form of carotene in plants. When used as a food coloring, it has the E number E160a.:119 The structure was deduced by Karrer et al. in 1930. In nature, β-carotene is a precursor (inactive form) to vitamin A via the action of beta-carotene 15,15'-monooxygenase. Isolation of β-carotene from fruits abundant in carotenoids is commonly done using column chromatography. It can also be extracted from the beta-carotene rich algae, Dunaliella salina. The separation of β-carotene from the mixture of other carotenoids is based on the polarity of a compound. β-Carotene is a non-polar compound, so it is separated with a non-polar solvent such as hexane. Being highly conjugated, it is deeply colored, and as a hydrocarbon lacking functional groups, it is very lipophilic.
  • 2.7K
  • 16 Nov 2022
Topic Review
Halophytes of the Mediterranean Basin
Halophytes represent an ancient and remarkable ecological group of annual or perennial plants with very complex features, whose definition and classification are still not univocal and often controversial. The species belonging to this group are very different from an ecological, morpho–physiological, and taxonomic point of view. Therefore, their definition can be subjective and vary a lot in the literature according to the different interpretations. However, following the most popular definition used in the literature, halophytes can be identified as plants that grow naturally, and complete their life cycle in environments that contain a higher salt content than most plant species can tolerate.
  • 2.7K
  • 23 Mar 2022
Topic Review
East African Lion
The East African lion is a Panthera leo melanochaita population in East Africa. During the 20th century, lion populations in this part of Africa became fragmented and declined in several range countries due to loss of habitat and prey base, poaching and killing of lions to protect livestock and human life. In 2005, a Lion Conservation Strategy was developed for East and Southern Africa. Today, lion populations are stable only in large protected area complexes. The scientific name P. l. melanochaita was proposed for the Cape lion in 1842 that was eradicated in the mid-19th century. P. l. melanochaita differs genetically from P. leo leo; the two subspecies probably diverged at least 50,000 years ago.
  • 2.7K
  • 01 Dec 2022
Topic Review
Coffee Cherry Structure and Processing
Coffee bean harvesting incurs various by-products known for their long traditional use. However, they often still end up being a waste instead of being used to their full potential. On the European market, coffee cherry (cascara) products are not yet common, and a novel food approval for beverages made from coffee cherry pulp was issued only recently. 
  • 2.7K
  • 08 Dec 2022
Topic Review
Chinese Alchemy
Chinese alchemy is an ancient Chinese scientific and technological approach to alchemy, a part of the larger tradition of Taoist body-spirit cultivation developed from the traditional Chinese understanding of medicine and the body. According to original texts such as the Cantong qi, the body is understood as the focus of cosmological processes summarized in the five agents, or wu xing, the observation and cultivation of which leads the practitioner into greater alignment with the operation of the Tao, the great cosmological principle of everything. Therefore, the traditional view in China is that alchemy focuses mainly on the purification of one's spirit and body in the hopes of gaining immortality through the practice of Qigong and/or consumption and use of various concoctions known as alchemical medicines or elixirs, each of which having different purposes. Pao zhi (Pao chi) cites the pharmacological processing (of Chinese materia medica) as used in the practice of Traditional Chinese Medicine, such as honey or wine frying and roasting with toxic metals such as mercury, lead, and arsenic. According to J.C. Cooper's Chinese Alchemy: The Taoist Quest for Immortality, Taoism had two distinct parts, the classical Tao Chia, which was mystical and stemmed primarily from Laozi and Zhuangzi, and the more popular Tao Chiao, which was the popular, magical and alchemical side of Taoism. Cooper states that a common viewpoint is that "classical Taoism [Daoism] was the original but was too austere and rarefied for the general populace ... [but] Tao Chiao fulfilled the day-to-day needs of the people."
  • 2.7K
  • 16 Nov 2022
Topic Review
Jump Point Search Algorithm
The JPS algorithm is a pathfinding algorithm that uses pruned neighbor rules as the search direction of nodes and the position of forced neighbors as the judgment of jump points.
  • 2.7K
  • 21 Jun 2022
Topic Review
Reaction Mechanism of CO2 Methanation
The combustion of fossil fuels has led to a large amount of carbon dioxide emissions and increased greenhouse effect. Methanation of carbon dioxide can not only mitigate the greenhouse effect, but also utilize the hydrogen generated by renewable electricity such as wind, solar, tidal energy, and others, which could ameliorate the energy crisis to some extent. Highly efficient catalysts and processes are important to make CO2 methanation practical. Although noble metal catalysts exhibit higher catalytic activity and CH4 selectivity at low temperature, their large-scale industrial applications are limited by the high costs. Ni-based catalysts have attracted extensive attention due to their high activity, low cost, and abundance. At the same time, it is of great importance to study the mechanism of CO2 methanation on Ni-based catalysts in designing high-activity and stability catalysts.
  • 2.7K
  • 07 Mar 2022
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