Your browser does not fully support modern features. Please upgrade for a smoother experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Lignin Biopolymer in Biomaterials Synthesis
Lignin is one of the wood and plant cell wall components that is available in large quantities in nature. Its polyphenolic chemical structure has been of interest for valorization and industrial application studies. Lignin can be obtained from wood by various delignification chemical processes, which give it a structure and specific properties that will depend on the plant species. Due to the versatility and chemical diversity of lignin, the chemical industry has focused on its use as a viable alternative of renewable raw material for the synthesis of new and sustainable biomaterials. 
  • 3.5K
  • 08 Apr 2021
Topic Review
Freeze-Drying of Foods
Freeze-drying is a process in which water is sublimated by the direct transition of water from solid (ice) to vapor, thus omitting the liquid state, and then desorbing water from the “dry” layer.
  • 3.5K
  • 16 Nov 2020
Topic Review
Zellige
Zellige (Arabic: [zˈliʑ]; Arabic: الزليج; also zelige or zellij) is mosaic tilework made from individually chiseled geometric tiles set into a plaster base. This form of Islamic art is one of the main characteristics of Moroccan architecture. It consists of geometrically patterned mosaics, used to ornament walls, ceilings, fountains, floors, pools and tables.
  • 3.5K
  • 06 Oct 2022
Topic Review Peer Reviewed
Urine Organic Acid Testing in the Clinical Laboratory: The Past, Current, and Future
Organic acidurias, a subgroup of inborn errors of metabolism (IEMs), are characterized by the accumulation of non-amine-containing, low-molecular-weight organic acids (OAs) in urine and/or plasma due to defects in specific metabolic pathways. Early diagnosis can be critical to enable timely intervention to prevent irreversible neurological injury or death. Therefore, urine organic acid (UOA) testing plays an indispensable role in the differential diagnosis of symptomatic individuals and the follow-up of abnormal newborn screen results. Historically, gas chromatography-mass spectrometry (GC-MS) has been the gold standard method, with well-established protocols for sample preparation and result interpretation. Recent advances in liquid chromatography-mass spectrometry (LC-MS), including both triple quadrupole and high-resolution Quadrupole Time-of-Flight (QTOF) platforms, have enabled UOA analysis with simplified workflows and improved coverage to diagnose a broader array of IEMs. This review summarizes the evolution of UOA testing from manual colorimetric assays to mass spectrometry-based platforms, highlights the analytical and interpretative considerations of GC-MS, and explores emerging LC-MS technologies and bioinformatics tools that offer enhanced diagnostic capabilities and efficiency for the future of IEM testing.
  • 3.5K
  • 25 Sep 2025
Topic Review Peer Reviewed
COVID-19 and Psychological Impact
The worldwide mental health burden associated to COVID-19. The psychological symptoms associated to COVID-19 can originate from three different sources: lockdowns, pandemic life and virus infection (both COVID-19 and post COVID-19 condition). Within the psychological symptoms it can be found: anxiety, depression, post-traumatic stress, fatigue and cognitive impairment (i.e., ’brain fog’, mental slowness, deficits in attention, executive functioning, working memory, learning, articulation, and/or psychomotor coordination). Plus, two psychological conditions associated to the COVID-19 pandemic have been coined so far by the World Health Organization: pandemic fatigue and post COVID-19 condition. The increase of psychological symptoms both in the general population and in frontline workers (especially health-care workers) generates an unprecedented number of psychological patients and it challenges national mental health systems. 
  • 3.5K
  • 13 Apr 2022
Topic Review
Factors Affecting Success of Entrepreneurship in Agribusinesses
Entrepreneurship and innovation are the fuel of economic growth. Understanding the motivational factors that lead to the success of entrepreneurs in agribusiness can be useful in affecting the degree of successful investment that accelerates development and economic growth in the agriculture sector. Entrepreneurship experience, risk-taking behavior, interest rates, and initial capital have a significant impact on the probability of entrepreneurship success and entrepreneur’s profits. Policies that could improve the skills of entrepreneurs, provision of initial capital requirements, and financial market efficiency had an effective role in increasing entrepreneurship and innovation in the agribusiness sector. Entrepreneurs in the field of agriculture could consider these factors to have better choices while entering or continuing with their agribusinesses.
  • 3.5K
  • 30 Jun 2022
Topic Review
Mac Transition to Apple Silicon
The Mac transition to Apple Silicon is the planned two-year process of introducing ARM64-based Apple silicon to, and deprecating Intel's x86-64 from, Apple's Macintosh line of computers. CEO Tim Cook announced the plan in his WWDC keynote address on June 22, 2020. The transition is the third time Apple has migrated Macintosh to a new instruction set architecture (ISA). The first was the switch from the Mac's original Motorola 68000 series architecture to the new PowerPC platform in 1994, and the second was the transition from PowerPC to Intel x86, which was formally announced in June 2005. Apple first utilized the ARM architecture in 1993 in its Newton personal digital assistant, and since then has extensively deployed it throughout other product lines including iPhone, iPad, iPod, and Apple Watch. Apple has designed its own custom ARM chips since 2009.
  • 3.5K
  • 02 Nov 2022
Topic Review
Agent-Based Programming
Intelligent and autonomous agents is a subarea of symbolic artificial intelligence where these agents decide, either reactively or proactively, upon a course of action by reasoning about the information that is available about the world (including the environment, the agent itself, and other agents). It encompasses a multitude of techniques, such as negotiation protocols, agent simulation, multi-agent argumentation, multi-agent planning, and many others. In an agent-based programming language, agents are the building blocks, and programs are obtained by programming their behaviours (how an agent reasons), their goals (what an agent aims to achieve) and their interoperation (how agents collaborate to solve a task).
  • 3.5K
  • 08 Mar 2021
Topic Review
End-of-Life Vehicle Management Systems in Southeast Aisa
End-of-life vehicle (ELV) management is becoming increasingly important as the automotive industry is one of the world’s most critical sectors and is rapidly expanding. ELV management is essential for environmental protection and wellbeing under Sustainable Development Goal (SDG) 3, provides more jobs under SDG 8, and promotes a circular economy under SDG 11. All these factors contribute to the importance of ELV management as a research topic. ELV management is well-positioned and an emerging research area particularly on ELV recycling systems in Europe, Japan, Korea, Taiwan and China. Immature ELV management systems in Malaysia, Thailand and Indonesia are the reason that no specific ELV laws and regulations exist, as well as why there are no precise ELV statistics. Nevertheless, there have been growing concerns about ELV management, as evidenced by environmental regulations and programs aimed at better management of ELV recycling in these countries.
  • 3.5K
  • 21 Nov 2022
Topic Review
Street Canyon
A street canyon (also known as an urban canyon) is a place where the street is flanked by buildings on both sides creating a canyon-like environment. Classic examples of these human-built canyons are made when streets separate dense blocks of structures, especially skyscrapers. These include the Magnificent Mile in Chicago, Toronto's Financial District, the Canyon of Heroes in Manhattan and Hong Kong's Kowloon and Central districts. Urban canyons affect various local conditions, including temperature, wind, air quality, and radio reception, including satellite navigation signals.
  • 3.5K
  • 26 Oct 2022
Topic Review
Hydrogen Storage Techniques for On-Board Applications
Hydrogen as an energy carrier could help decarbonize industrial, building, and transportation sectors, and be used in fuel cells to generate electricity, power, or heat. One of the numerous ways to solve the climate crisis is to make the vehicles on our roads as clean as possible. Fuel cell electric vehicles (FCEVs) have demonstrated a high potential in storing and converting chemical energy into electricity with zero carbon dioxide emissions. This text presents the most favorable hydrogen storage approaches for FCEV on-board applications. To achieve long-range autonomy (over 500 km), FCEVs must be capable of storing 5-10 kg of hydrogen in compressed vessels at 700 bar, with Type IV vessels being the primary option. Although physical and chemical storage technologies are expected to be valuable to the hydrogen economy, compressed hydrogen storage remains the most advanced technology for on-board applications.
  • 3.5K
  • 09 Aug 2023
Topic Review
Platelets
Recent advances in proteomic studies provided additional important information concerning the platelet biology and their response to several pathophysiological pathways. Platelets indeed are a heterogeneous small anucleate blood cell population with a central role both in physiological haemostasis and in pathological states, spanning from thrombosis to inflammation, and cancer.  Herein, a critical overview is provided on principal platelet proteomic studies focused on platelet biology from signalling to granules content, platelet proteome changes in several diseases, and the impact of drugs on platelet functions. Targeted quantification methods by means of mass spectrometry might be employed for more precise, robust and accurate quantification of selected proteins, which might be used as biomarkers for disease diagnosis, prognosis and therapy, and their strong clinical impact in the near future.
  • 3.5K
  • 07 Jul 2020
Topic Review
Napoleon's Theorem
In geometry, Napoleon's theorem states that if equilateral triangles are constructed on the sides of any triangle, either all outward or all inward, the lines connecting the centres of those equilateral triangles themselves form an equilateral triangle. The triangle thus formed is called the inner or outer Napoleon triangle. The difference in area of these two triangles equals the area of the original triangle. The theorem is often attributed to Napoleon Bonaparte (1769–1821). Some have suggested that it may date back to W. Rutherford's 1825 question published in The Ladies' Diary, four years after the French emperor's death, but the result is covered in three questions set in an examination for a Gold Medal at the University of Dublin in October, 1820, whereas Napoleon died the following May.
  • 3.5K
  • 24 Oct 2022
Topic Review
Sovereign Citizen Movement
The sovereign citizen movement is a loose grouping of primarily American litigants, commentators, tax protesters, and financial-scheme promoters, who claim to be answerable only to their particular interpretations of the common law and to not be subject to any government statutes or proceedings. In the United States, they do not recognize U.S. currency and maintain that they are "free of any legal constraints". They especially reject most forms of taxation as illegitimate. Participants in the movement argue this concept in opposition to the idea of "federal citizens", who, they say, have unknowingly forfeited their rights by accepting some aspect of federal law. The doctrines of the movement resemble those of the freemen on the land movement more commonly found in the British Commonwealth, such as Australia and Canada. Many members of the sovereign citizen movement claim that the United States government is illegitimate. The sovereign citizen movement has been described as consisting of individuals who assert that the county sheriff is the most powerful law-enforcement officer in the country, with authority superior to that of any federal agent, elected official, or local law-enforcement official. The movement can be traced back to white-extremist groups like Posse Comitatus and the constitutional militia movement. It also includes members of certain self-declared "Moorish" sects. While the movement was originally associated with White supremacism, it now includes varying racial ideologies as well as a variety of people, most commonly white and African American. The Federal Bureau of Investigation (FBI) classifies some sovereign citizens ("sovereign citizen extremists") as domestic terrorists. In 2010, the Southern Poverty Law Center (SPLC) estimated that approximately 100,000 Americans were "hard-core sovereign believers", with another 200,000 "just starting out by testing sovereign techniques for resisting everything from speeding tickets to drug charges". In surveys conducted in 2014 and 2015, representatives of U.S. law enforcement ranked the risk of terrorism from the sovereign citizen movement higher than the risk from any other group, including Islamic extremists, militias, racists, and neo-Nazis. The New South Wales Police Force in Australia has also identified sovereign citizens as a potential terrorist threat.
  • 3.5K
  • 24 Nov 2022
Topic Review
α-Lactalbumin
α-Lactalbumin (α-LA) is a small (Mr 14,200), acidic (pI 4-5), Ca2+-binding protein. α-LA is a regulatory component of lactose synthase enzyme system. α-LA is very important in infant nutrition since it constitutes a large part of the whey and total protein in human milk. The protein possesses a single strong Ca2+-binding site, which can also bind Mg2+, Mn2+, Na+, K+, and some other metal cations. It contains several distinct Zn2+-binding sites. Physical properties of α-LA strongly depend on the occupation of its metal binding sites by metal ions. In the absence of bound metal ions α-LA is in the molten globule-like state. The binding of metal ions, and especially of Ca2+, increases stability of α-LA against action of heat, various denaturing agents, and proteases, while the binding of Zn2+ to the Ca2+-loaded protein decreases its stability and causes its aggregation. The thermal unfolding of apo-α-LA takes place in the temperature region from 10 to 30 °C. The binding of Ca2+ under the conditions of low ionic strength shifts the thermal transition to higher temperatures by more than 40 °C. The binding of Mg2+, Na+, and K+ increases protein stability as well. The stronger an ion binds to the protein, the more pronounced the thermal transition shift. All four classes of surfactants (anionic, cationic, non-ionic, and zwitterionic) denature α-LA and the denaturation involves at least one intermediate. The position of any denaturation transition in α-LA (half-transition temperature, half-transition pressure, half-transition denaturant concentration) depends upon metal ion concentration in solution (especially if this metal ion is Ca2+). Therefore, values of denaturation temperature or urea or guanidine hydrochloride denaturing concentration are relatively meaningless for α-LA without specifying the metal ion content(s) and their solution concentration(s). At a neutral or slightly acidic pH at a physiological temperature, α-LA can associate with membranes. The conformations of the membrane-bound protein range from native-like to molten globule-like states. At a low pH, α-LA penetrates the interior of the negatively charged membranes and exhibits a molten globule conformation. Depending on external conditions, α-LA can form amyloid fibrils, amorphous aggregates, nanoparticles, and nanotubes. At pH 2, α-LA in the classical molten globule conformation can form amyloid fibrils. Some of these aggregated states of α-LA (nanoparticles, nanotubes) can be used in practical applications such as drug delivery to tissues and organs. The structure and self-assembly behavior of α-LA are governed by a subtle balance between hydrophobic and polar interactions and this balance can be finely tuned through the addition of selected substances. Small size nanoparticles of α-LA (100 to 200 nm) can be obtained with the use of various desolvating agents. Partially hydrolyzed α-LA can form nanotubes. α-LA and some of its fragments possess bactericidal and antiviral activities. Complexes of partially unfolded α-LA with oleic acid showed significant cytotoxicity to various tumor and bacterial cells. α-LA in such complexes plays a role of a delivery carrier of cytotoxic fatty acid molecules into tumor cells across the cell membrane. Cytotoxic protein–oleic acid complexes possess a common core-shell structure, where an oily core is made of a micellar oleic acid, whereas a proteinaceous shell, which stabilizes the oleic acid micelle, is formed from the flexible, partially unfolded proteins. These complexes called liprotides (lipids and partially denatured proteins), which are potential novel anti-tumorous drugs, can be considered as molten globular containers filled with the toxic oil.
  • 3.5K
  • 31 Aug 2020
Topic Review
Pudu (Genus)
The pudus (Mapudungun püdü or püdu, Spanish: pudú, Spanish pronunciation: [puˈðu]) are two species of South American deer from the genus Pudu, and are the world's smallest deer. The name is a loanword from Mapudungun, the language of the indigenous Mapuche people of central Chile and south-western Argentina. The two species of pudus are the northern pudu (Pudu mephistophiles) from Venezuela, Colombia, Ecuador, and Peru, and the southern pudu (Pudu puda; sometimes incorrectly modified to Pudu pudu) from southern Chile and south-western Argentina . Pudus range in size from 32 to 44 centimeters (13 to 17 in) tall, and up to 85 centimeters (33 in) long. The southern pudu is currently classified as near threatened, while the northern pudu is classified as Data Deficient in the IUCN Red List.
  • 3.5K
  • 20 Oct 2022
Topic Review
Biological Degradation of Polymers
Biodegradable plastics can make an important contribution to the struggle against increasing environmental pollution through plastics. This entry provides an overview of the main environmental conditions in which biodegradation takes place and then presents the degradability of numerous polymers. 
  • 3.5K
  • 23 Nov 2020
Topic Review
Synthesis of Thienothiophenes
Thienothiophenes (TT), formed by two annulated thiophene rings, represent fully the planar system, whose embedding into a molecular architecture can significantly improve/alter the fundamental properties of organic, π-conjugated materials. 
  • 3.5K
  • 21 Nov 2022
Topic Review
Sensation Seeking Scale
The Sensation Seeking Scale is one of the most common psychological instrument for measuring sensation seeking. It was created in 1964 by Marvin Zuckerman, at the University of Delaware. Zuckerman created the scale with the purpose of better understanding personality traits such as neuroticism, antisocial behavior, and psychopathy. This has gone through a few iterations and is currently on its 1978 version: SSS-V. There are 4 different aspects (subscales), which are: Thrill and Adventure Seeking (TAS); Disinhibition (Dis); Experience Seeking (ES); and Boredom Susceptibility (BS). Each subscale contains 10 items, making a total of 40 items. Zuckerman has proposed that these 'traits' come from a psycho-biological interaction.
  • 3.5K
  • 21 Oct 2022
Topic Review
Climate Change Maladaptation
Maladaptation is caused by adaptation that fails to reduce vulnerability or inadvertently increases it. Maladaptation can be defined as: ''maladaptation occurs when short-term strategies increase vulnerability in the long term'' or ''action taken ostensibly to avoid or reduce vulnerability to climate change that impacts adversely on, or increase the vulnerability of other systems, sectors, or social groups.''
  • 3.5K
  • 29 Mar 2021
  • Page
  • of
  • 2798
Featured Entry Collections
>>

Featured Reprints

>>
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Medieval Royal Iconography
Academic Video Service
Feedback