Search | Encyclopedia MDPI

You're using an outdated browser. Please upgrade to a modern browser for the best experience.

Subject:

Sort by:

Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)

Filter:

All Topic Review Biography Peer Reviewed Entry Video Entry

Topic Review

Applications of Cyclodextrins

Due to their unique structural, physical and chemical properties, cyclodextrins and their derivatives have been of great interest to scientists and researchers in both academia and industry for over a century. Many of the industrial applications of cyclodextrins have arisen from their ability to encapsulate, either partially or fully, other molecules, especially organic compounds. Cyclodextrins are non-toxic oligopolymers of glucose that help to increase the solubility of organic compounds with poor aqueous solubility, can mask odors from foul-smelling compounds, and have been widely studied in the area of drug delivery.

8.6K
29 Mar 2022

Topic Review

College Students Career Decision-Making Difficulties

College students suffer from various difficulties due to their own and environmental reasons in the process of career decision-making, which may affect their individual psychological state and social functions over time. One of the main difficulties is career decision-making. Career decision-making difficulties refer to various difficulties or problems faced by individuals in the process of career decision-making, including lack of readiness (LR), lack of information (LI), and inconsistent information (II). College students have certain career decision-making difficulties due to the lack of occupational information and self-information. The career decision-making difficulties not only affect college students’ employment, but also affect their solutions to the problems in career development.

8.6K
02 Jul 2021

Topic Review

Prehistoric Paintings in Magura Cave

The paintings are made of bat guano applied over limestone, therefore two sets of laboratory specimens were considered: stone specimens and stone specimens covered with a layer of sterilized bat guano. The two investigated treatments were a commercial product based on ethyl silicate (“ES”) and a solution of diammonium hydrogen phosphate (“DAP”), aimed at forming calcium phosphates. The results of the study indicate that both treatments were able to increase mechanical properties of stone, the increase being higher for “DAP”. Both consolidants caused acceptable color changes, but the “ES” treatment significantly decreased stone wettability, water absorption and water vapor permeability, while the “DAP” treatment slightly affected those properties. In the stone+guano specimens, the presence of the guano layer affected the penetration of the consolidants, thus partly reducing their effectiveness. Compared to the stone samples, the guano layer experienced a more intense color change, alongside visible cracking. However, the adopted methodology to replicate the cave paintings was not completely successful, as the so-deposited guano layer was very prone to detachment when dry, unlike cave paintings. Future work will be dedicated to assess the consolidant performance onto samples that resemble even more closely the conditions of the cave paintings, by improving the methodology for the guano layer deposition and by contaminating specimens with soluble salts before consolidant application.

8.5K
02 Nov 2020

Topic Review

German Question

"The German Question" was a debate in the 19th century, especially during the Revolutions of 1848, over the best way to achieve a unification of all or most lands inhabited by Germans. From 1815 to 1866, about 37 independent German-speaking states existed within the German Confederation. The Großdeutsche Lösung ("Greater German solution") favored unifying all German-speaking peoples under one state, and was promoted by the Austrian Empire and its supporters. The Kleindeutsche Lösung ("Little German solution") sought only to unify the northern German states and did not include any part of Austria (either its German-inhabited areas or its areas dominated by other ethnic groups); this proposal was favored by the Kingdom of Prussia. The solutions are also referred to by the names of the states they proposed to create, Kleindeutschland and Großdeutschland ("Little Germany" and "Greater Germany"). Both movements were part of a growing German nationalism. They also drew upon similar contemporary efforts to create a unified nation state of people who shared a common ethnicity and language, such as the unification of Italy by the House of Savoy and the Serbian Revolution. During the Cold War, the term also referred to the matters pertaining to the division, and re-unification, of Germany.

8.5K
21 Nov 2022

Topic Review

The kilowatt hour (symbol: kW⋅h, kW h, or kWh) is a unit of energy equal to 3.6 megajoules. If energy is transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt hours is equal to the power in kilowatts multiplied by the time in hours. The kilowatt hour is commonly used as a billing unit for energy delivered to consumers by electric utilities.

8.5K
14 Nov 2022

Topic Review

Mass media refers to a diverse range of communication channels that transmit information and entertainment content to a large audience. This encompasses traditional mediums such as newspapers, television, and radio, as well as modern digital platforms like the internet and social media. Mass media plays a crucial role in shaping public opinion, disseminating news, and influencing societal norms on a global scale.

8.5K
25 Jan 2024

Topic Review

Melatonin Protects Mitochondria and Adenosine Triphosphate Production

Melatonin (N-acetyl-5-methoxytryptamine) is a ubiquitous, mitochondria-targeted molecule present in all tested eukarya and bacteria. In March 2022, the first discovery of the serotonin N-acetyltransferase (SNAT) gene—responsible for the penultimate formation of N-acetylserotonin (NAS) before its final conversion into melatonin — in archaea further consolidates the status of melatonin as a regulator of biomolecular condensates in all three domains of life in the cellular empire. RNA viruses including SARS-CoV-2 contain proteins with intrinsically disordered regions that undergo liquid-liquid phase separation (LLPS). Liquid-liquid phase separation (LLPS) of these proteins form membraneless condensates that act as “viral factories” to facilitate and enhance replication. Phase separation of the SARS-CoV-2 nucleocapsid (N) protein is associated with mitochondrial dysfunction and rewiring of energy production away from oxidative phosphorylation (OXPHOS) to favor aerobic glycolysis in cytoplasm. Increased adenosine triphosphate (ATP) in cytoplasm supports viral replication. Melatonin protects mitochondria from damage, maintains adequate levels to disassemble “viral factories”, and prevents suppression of host antiviral immune responses by inhibiting nucleocapsid phase separation via antioxidant-dependent and -independent means.

8.5K
05 Sep 2022

Topic Review

AirPort Time Capsule

The AirPort Time Capsule (originally named Time Capsule) was a wireless router sold by Apple Inc., featuring network-attached storage (NAS) and a residential gateway router, and is one of Apple's AirPort products. They are, essentially, versions of the AirPort Extreme with an internal hard drive. Apple describes it as a "Backup Appliance", designed to work in tandem with the Time Machine backup software utility introduced in Mac OS X 10.5. Introduced on January 15, 2008 and released on February 29, 2008, the device has been upgraded several times, matching upgrades in the Extreme series routers. The earliest versions supported 802.11n wireless and came with a 500 GB hard drive in the base model, while the latest model, introduced in 2013, features 802.11ac and a 3 TB hard drive. All models include three Gigabit Ethernet ports and a single USB port. The USB port can be used for external peripheral devices to be shared over the network, such as external hard drives or printers. The NAS functionality utilizes a built-in "server grade" hard drive. On April 26, 2018, Bloomberg News announced that Apple Inc. entire AirPort line had been discontinued without replacement.

8.5K
04 Nov 2022

Topic Review

Democratic Socialism

Democratic socialism is a political philosophy that supports political democracy and some form of a socially owned economy,({{{1}}}, {{{2}}}) with a particular emphasis on economic democracy, workplace democracy, and workers' self-management within a market socialist economy, or an alternative form of decentralised planned socialist economy. Democratic socialists argue that capitalism is inherently incompatible with the values of freedom, equality, and solidarity and that these ideals can only be achieved through the realisation of a socialist society. Although most democratic socialists seek a gradual transition to socialism,({{{1}}}, {{{2}}}) democratic socialism can support either revolutionary or reformist politics as means to establish socialism.({{{1}}}, {{{2}}}) Democratic socialism was popularized by socialists who were opposed to the backsliding towards a one-party state in the Soviet Union and other nations during the 20th century.({{{1}}}, {{{2}}}) The history of democratic socialism can be traced back to 19th-century socialist thinkers across Europe and the Chartist movement in Britain, which somewhat differed in their goals but shared a common demand of democratic decision making and public ownership of the means of production, and viewed these as fundamental characteristics of the society they advocated for. In the late 19th to the early 20th century, democratic socialism was also heavily influenced by the gradualist form of socialism promoted by the British Fabian Society and Eduard Bernstein's evolutionary socialism in Germany.({{{1}}}, {{{2}}}) Democratic socialism is what most socialists understand by the concept of socialism;({{{1}}}, {{{2}}}) it may be a very broad (socialists who reject a one-party Marxist–Leninist state)({{{1}}}, {{{2}}}) or more limited concept (post-war social democracy).({{{1}}}, {{{2}}}) As a broad movement, it includes forms of libertarian socialism,({{{1}}}, {{{2}}}) market socialism,({{{1}}}, {{{2}}}) reformist socialism, and revolutionary socialism,({{{1}}}, {{{2}}}) as well as ethical socialism,({{{1}}}, {{{2}}}) liberal socialism,({{{1}}}, {{{2}}}) social democracy,({{{1}}}, {{{2}}}) and some forms of state socialism and utopian socialism, all of which share commitment to democracy.({{{1}}}, {{{2}}}) Democratic socialism is contrasted with Marxism–Leninism, which opponents often perceive as being authoritarian and undemocratic in practice.({{{1}}}, {{{2}}}) Democratic socialists oppose the Stalinist political system and the Soviet-type economic planning system, rejecting as their form of governance the administrative-command system that formed in the Soviet Union and other Marxist–Leninist states during the 20th century. Democratic socialism is also distinguished from Third Way social democracy[nb 1] on the basis that democratic socialists are committed to systemic transformation of the economy from capitalism to socialism.[nb 2] While having socialism as a long-term goal,({{{1}}}, {{{2}}}) some moderate democratic socialists are more concerned about curbing capitalism's excesses, and are supportive of progressive reforms to humanise it in the present day,({{{1}}}, {{{2}}}) while other democratic socialists believe that economic interventionism and similar policy reforms aimed at addressing social inequalities and suppressing the economic contradictions of capitalism would only exacerbate the contradictions,({{{1}}}, {{{2}}}) causing them to emerge elsewhere under a different guise.({{{1}}}, {{{2}}}) Those democratic socialists believe that the fundamental issues with capitalism are systemic in nature, and can only be resolved by replacing the capitalist mode of production with the socialist mode of production through the replacement of private ownership with collective ownership of the means of production, and extending democracy to the economic sphere in the form of industrial democracy.({{{1}}}, {{{2}}}) The main criticism of democratic socialism is focused on the compatibility of democracy and socialism. Several academics and political commentators tend to distinguish between authoritarian socialism and democratic socialism as a political ideology, with the first representing the Soviet Bloc, and the latter representing the democratic socialist parties in the Western Bloc countries that have been democratically elected in countries such as Britain, France, and Sweden, among others.({{{1}}}, {{{2}}}) However, following the end of the Cold War, many of these countries have moved away from socialism as a neoliberal consensus replaced the social democratic consensus in the advanced capitalist world.

8.5K
17 Oct 2022

Topic Review

Christian Views on Hell

In Christian theology, Hell is the place or state into which, by God's definitive judgment, unrepentant sinners pass in the general judgment, or, as some Christians believe, immediately after death (particular judgment). Its character is inferred from teaching in the biblical texts, some of which, interpreted literally, have given rise to the popular idea of Hell. Theologians today generally see Hell as the logical consequence of using free will to reject union with God and, because God will not force conformity, it is not incompatible with God's justice and mercy. Different Hebrew and Greek words are translated as "Hell" in most English-language Bibles. These words include: "Sheol" in the Hebrew Bible, and "Hades" in the New Testament. Many modern versions, such as the New International Version, translate Sheol as "grave" and simply transliterate "Hades". It is generally agreed that both sheol and hades do not typically refer to the place of eternal punishment, but to the grave, the temporary abode of the dead, the underworld. "Gehenna" in the New Testament, where it is described as a place where both soul and body could be destroyed (Matthew 10:28) in "unquenchable fire" (Mark 9:43). The word is translated as either "Hell" or "Hell fire" in many English versions. Gehenna was a physical location outside the city walls where they burned garbage and where lepers and outcasts were sent, hence the weeping and gnashing of teeth. The Greek verb ταρταρῶ (tartarō, derived from Tartarus), which occurs once in the New Testament (in 2 Peter 2:4), is almost always translated by a phrase such as "thrown down to hell". A few translations render it as "Tartarus"; of this term, the Holman Christian Standard Bible states: "Tartarus is a Greek name for a subterranean place of divine punishment lower than Hades."

8.5K
18 Oct 2022

Topic Review

α- and β-Pinene

α- and β-pinene are well-known representatives of the monoterpenes group, and are found in many plants’ essential oils. A wide range of pharmacological activities have been reported, including antibiotic resistance modulation, anticoagulant, antitumor, antimicrobial, antimalarial, antioxidant, anti-inflammatory, anti-Leishmania, and analgesic effects.

8.5K
23 Jul 2021

Topic Review

The Lisbon Treaty has brought significant changes to the institutional structure of the European Union. The traditional three pillar system has been abolished and provisions regarding formal Union institutions have been amended. The aim of this encyclopedia entry is to briefly describe the functioning of each of the formal EU institutions after the Lisbon amendment. More specifically, their main tasks and powers will be shortly presented, whilst more extensive bibliography will be provided. In this regard, the reader will be in position to understand the fundamentals of the EU institutional structure and also find valuable sources for further research.

8.5K
16 Mar 2021

Topic Review

Proton–Proton Chain

The proton–proton chain, also commonly referred to as the p-p chain, is one of two known sets of nuclear fusion reactions by which stars convert hydrogen to helium. It dominates in stars with masses less than or equal to that of the Sun, whereas the CNO cycle, the other known reaction, is suggested by theoretical models to dominate in stars with masses greater than about 1.3 times that of the Sun. In general, proton–proton fusion can occur only if the kinetic energy (i.e. temperature) of the protons is high enough to overcome their mutual electrostatic repulsion. In the Sun, deuterium-producing events are rare. Diprotons are the much more common result of proton–proton reactions within the star, and diprotons almost immediately decay back into two protons. Since the conversion of hydrogen to helium is slow, the complete conversion of the hydrogen initially in the core of the Sun is calculated to take more than ten billion years. Although sometimes called the "proton–proton chain reaction", it is not a chain reaction in the normal sense. In most nuclear reactions, a chain reaction designates a reaction that produces a product, such as neutrons given off during fission, that quickly induces another such reaction. The proton-proton chain is, like a decay chain, a series of reactions. The product of one reaction is the starting material of the next reaction. There are two main chains leading from Hydrogen to Helium in the Sun. One chain has five reactions, the other chain has six.

8.5K
10 Nov 2022

Topic Review

Lists of Mathematics Topics

This article itemizes the various lists of mathematics topics. Some of these lists link to hundreds of articles; some link only to a few. The template to the right includes links to alphabetical lists of all mathematical articles. This article brings together the same content organized in a manner better suited for browsing. The purpose of this list is not similar to that of the Mathematics Subject Classification formulated by the American Mathematical Society. Many mathematics journals ask authors of research papers and expository articles to list subject codes from the Mathematics Subject Classification in their papers. The subject codes so listed are used by the two major reviewing databases, Mathematical Reviews and Zentralblatt MATH. This list has some items that would not fit in such a classification, such as list of exponential topics and list of factorial and binomial topics, which may surprise the reader with the diversity of their coverage.

8.5K
19 Oct 2022

Topic Review

Natural Emulsion Stabilizers

Natural emulsion stabilizers are polymers of amino acid, nucleic acid, carbohydrate, etc., which are derived from microorganisms, bacteria, and other organic materials. Plant and animal proteins are basic sources of natural emulsion stabilizers. Pea protein-maltodextrin and lentil protein feature entrapment capacity up to 88%, (1–10% concentrated), zein proteins feature 74–89% entrapment efficiency, soy proteins in various concentrations increase dissolution, retention, and stability to the emulsion and whey proteins, egg proteins, and proteins from all other animals are applicable in membrane formation and encapsulation to stabilize emulsion/nanoemulsion. In pharmaceutical industries, phospholipids, phosphatidyl choline (PC), phosphatidyl ethanol-amine (PE), and phosphatidyl glycerol (PG)-based stabilizers are very effective as emulsion stabilizers. Lecithin (a combination of phospholipids) is used in the cosmetics and food industries. Various factors such as temperature, pH, droplets size, etc. destabilize the emulsion. Therefore, the emulsion stabilizers are used to stabilize, preserve and safely deliver the formulated drugs, also as a preservative in food and stabilizer in cosmetic products. Natural emulsion stabilizers offer great advantages because they are naturally degradable, ecologically effective, non-toxic, easily available in nature, non-carcinogenic, and not harmful to health.

8.5K
19 Jan 2022

Topic Review

The entry explores the concept of food heritage, focusing mainly on the anthropological, geographical, and sociological debate. Although the review identifies some conceptualisations that frame heritage in the food and gastronomic domains, it also shows the high degree of fragmentation of the debate. In so doing, it sheds light on how the concept of food heritage from a theoretical point of view is still in progress.

8.5K
02 Feb 2022

Topic Review

Natural Biopolymers

Natural biopolymers are an interesting resource for edible films production, as they are environmentally friendly packaging materials.

8.5K
23 Jun 2021

Topic Review

Ego-Dystonic Sexual Orientation

Ego-dystonic sexual orientation is an ego-dystonic mental disorder characterized by having a sexual orientation or an attraction that is at odds with one's idealized self-image, causing anxiety and a desire to change one's orientation or become more comfortable with one's sexual orientation. It describes not innate sexual orientation itself, but a conflict between the sexual orientation one wishes to have and the sexual orientation one actually possesses.

8.5K
14 Oct 2022

Topic Review

Methods of Preparation of Quinoxalines

Quinoxaline is a fused heterocycle system of a benzene ring and pyrazine ring. It has earned considerable attention due to its importance in the field of medicinal chemistry. The system is of extensive importance due to its comprehensive array of biological activities. Quinoxaline derivatives have been used as anticancer, anticonvulsant, anti-inflammatory, antidiabetic, antioxidant, antibacterial, anti-TB, antimalarial, antiviral, anti-HIV, and many other uses. Variously substituted quinoxalines are significant therapeutic agents in the pharmaceutical industry.

8.5K
23 Nov 2023

Topic Review

Lipsticks History, Formulations, and Production

Lipsticks are one of the most widely used cosmetic products. Social, psychological, and therapeutic benefits can be attained from using lipstick. The beauty and attractiveness of a person are enhanced as lipsticks colour the lips and protect them from the external environment.

8.5K
02 Mar 2022

Page
of
2714

Featured Entry Collections

>>

Featured Books

>>

Encyclopedia of COVID-19

Encyclopedia of Engineering

Encyclopedia of Social Sciences

Encyclopedia of Social Sciences
Chief Editor: Kum Fai Yuen

Encyclopedia of Digital Society, Industry 5.0 and Smart City

Encyclopedia of Digital Society, Industry 5.0 and Smart City
Chief Editor: Sandro Serpa

Academic Video Service

Feedback

Top