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
Dialysis
In medicine, dialysis (from Greek διάλυσις, dialysis, "dissolution"; from διά, dia, "through", and λύσις, lysis, "loosening or splitting") is the process of removing excess water, solutes, and toxins from the blood in people whose kidneys can no longer perform these functions naturally. This is referred to as renal replacement therapy. The first successful dialysis was performed in 1943. Dialysis may need to be initiated when there is a sudden rapid loss of kidney function, known as acute kidney injury (previously called acute renal failure), or when a gradual decline in kidney function, chronic kidney disease, reaches stage 5. Stage 5 chronic renal failure is reached when the glomerular filtration rate is 10–15% of normal, creatinine clearance is less than 10 mL per minute and uremia is present. Dialysis is used as a temporary measure in either acute kidney injury or in those awaiting kidney transplant and as a permanent measure in those for whom a transplant is not indicated or not possible. In Australia, Canada, the United Kingdom, and the United States, dialysis is paid for by the government for those who are eligible. In research laboratories, dialysis technique can also be used to separate molecules based on their size. Additionally, it can be used to balance buffer between a sample and the solution "dialysis bath" or "dialysate" that the sample is in. For dialysis in a laboratory, a tubular semipermeable membrane made of cellulose acetate or nitrocellulose is used. Pore size is varied according to the size separation required with larger pore sizes allowing larger molecules to pass through the membrane. Solvents, ions and buffer can diffuse easily across the semipermeable membrane, but larger molecules are unable to pass through the pores. This can be used to purify proteins of interest from a complex mixture by removing smaller proteins and molecules.
  • 3.3K
  • 07 Nov 2022
Topic Review
Techniques for Dealcoholization of Wines
To adapt to the trends in wine styles, and the effect of climate change on wine alcohol content, different techniques have been used at the various stages of winemaking, among which the physical dealcoholization techniques, particularly membrane separation (nanofiltration, reverse osmosis, evaporative perstraction, and pervaporation) and thermal distillation (vacuum distillation and spinning cone column), have shown promising results and hence are being used for commercial production.
  • 3.3K
  • 29 Oct 2021
Topic Review
Triboelectric Nanogenerator
First proposed by Wang in 2012, the triboelectric nanogenerator (TENG, also called Wang generator) derived from Maxwell’s displacement current shows great prospect as a new technology to convert mechanical energy into electricity, based on the triboelectrification effect and electrostatic induction. TENGs present superiorities including light weight, cost-effectiveness, easy fabrication, and versatile material choices. The concept of harvesting blue energy using the TENG and its network was first brought out in 2014. As a new form of blue energy harvester, the TENG surpasses the EMG in that it intrinsically displays higher effectiveness under low frequency, owing to the unique feature of its output characteristics. Moreover, adopting the distributed architecture of light-weighted TENG networks can make it more suitable for collecting wave energy of high entropy compared with EMGs, which are oversized in volume and mass.
  • 3.3K
  • 13 Sep 2021
Topic Review
The Occurrence of Microorganisms in Grassland Soils
Soil microorganisms are responsible for the mineralization of organic compounds and the course of various biogeochemical cycles. They have an influence on the biodiversity of entire ecosystems, including the plant cover. They are responsible for the productivity of soil and its structure, and they also affect the circulation of elements in nature. The count and species composition of soil microorganisms depend mainly on the physicochemical properties of the pedon, the amount of nutrients, the type of soil, and the species composition of the plant community. Plants significantly influence the species composition of soil microbial communities through the release or loss of compounds from plant roots to the surrounding soil environment and decomposition of litter and roots.
  • 3.3K
  • 19 May 2022
Topic Review
Antimony as a Critical Raw Material
Antimony is widely acknowledged as a critical raw material of worldwide significance, based on its recognition by many countries. According to current projections, there is an anticipated increase in the demand for antimony in the forthcoming years. An issue of significant concern within the supply chain, which poses a substantial obstacle to sustainable development, is the global unequal allocation of abundant antimony resources. Most nations exhibited a high degree of dependence on a few countries for their net imports of antimony, resulting in a notable disruption and raising concerns regarding the supply chain. 
  • 3.3K
  • 23 Feb 2024
Topic Review
Torii
A torii (鳥居, literally bird abode, Japanese pronunciation: [to.ɾi.i]) is a traditional Japan ese gate most commonly found at the entrance of or within a Shinto shrine, where it symbolically marks the transition from the mundane to sacred. The presence of a torii at the entrance is usually the simplest way to identify Shinto shrines, and a small torii icon represents them on Japanese road maps.[note 1] The first appearance of Torii gates in Japan can be reliably pinpointed to at least the mid-Heian period because they are mentioned in a text written in 922. The oldest existing stone torii was built in the 12th century and belongs to a Hachiman Shrine in Yamagata prefecture. The oldest wooden torii is a ryōbu torii (see description below) at Kubō Hachiman Shrine in Yamanashi prefecture built in 1535. Torii gates were traditionally made from wood or stone, but today they can be also made of reinforced concrete, copper, stainless steel or other materials. They are usually either unpainted or painted vermilion with a black upper lintel. Inari shrines typically have many torii because those who have been successful in business often donate in gratitude a torii to Inari, kami of fertility and industry. Fushimi Inari-taisha in Kyoto has thousands of such torii, each bearing the donor's name.
  • 3.3K
  • 06 Nov 2022
Topic Review
Climatic Changes on Cucumber Growth, Flower, Fruit Development
Environmental changes, both natural and anthropogenic, mainly related to rising temperatures and water scarcity, are clearly visible around the world. Climate change is important for crop production and is a major issue for the growth and productivity of cucumbers. Processes such as sex determination, flower morphogenesis and fruit development in cucumbers are highly sensitive to various forms of stress induced by climatic changes.
  • 3.3K
  • 08 Oct 2023
Topic Review
Novichok Agent
A Novichok agent (Russian: Новичо́к, "newcomer", "novice", "newbie") is a group of nerve agents, some of which are binary chemical weapons. The agents were developed at the GosNIIOKhT state chemical research institute by the Soviet Union and Russia between 1971 and 1993.[lower-alpha 1] Some Novichok agents at STP are solids while others are liquids. It is thought that dispersal for the solids is possible by ultrafine powder. Russian scientists who developed the nerve agents claim they are the deadliest ever made, with some variants possibly five to eight times more potent than VX, and others up to ten times more potent than soman. As well as Russia, Novichok agents have been known to be produced in Iran. In the 21st century, Novichok agents came to public attention after they were used to poison opponents of the Russian government, including the Skripals and two others in Amesbury, UK (2018) and Alexei Navalny (2020), but civil poisonings with this substance have been known since at least 1995. In November 2019, the Organisation for the Prohibition of Chemical Weapons (OPCW), which is the executive body for the Chemical Weapons Convention (CWC), added the Novichok agents to "list of controlled substances" of the CWC "in one of the first major changes to the treaty since it was agreed in the 1990s" in response to the 2018 poisonings in the UK.
  • 3.3K
  • 11 Nov 2022
Topic Review
Non-Native Guinea Grass
Guinea grass (Panicum maximum Jacq., renamed Megathyrsus maximus Jacq.) is a native forage plant in Africa of great economic value, but it was introduced in almost all tropical countries as a source of animal forage.
  • 3.3K
  • 30 Jun 2021
Topic Review
Autobiographical Memory
Autobiographical memory is a memory system consisting of episodes recollected from an individual's life, based on a combination of episodic (personal experiences and specific objects, people and events experienced at particular time and place) and semantic (general knowledge and facts about the world) memory. It is thus a type of explicit memory.
  • 3.3K
  • 28 Nov 2022
Topic Review
Notch Signaling Function in Angiogenesis
The Notch signaling pathway is a major regulator of vascular morphogenesis, managing endothelial response to vascular growth factors, endothelial specialization, establishment and maintenance of vascular identity as venous or arterial and vascular maturation.
  • 3.3K
  • 03 Dec 2020
Topic Review
Soyuz 11
Soyuz 11 (Russian: Союз 11, lit. 'Union 11') was the only crewed mission to board the world's first space station, Salyut 1 (Soyuz 10 had soft-docked, but had not been able to enter due to latching problems). The crew, Georgy Dobrovolsky, Vladislav Volkov, and Viktor Patsayev, arrived at the space station on 7 June 1971, and departed on 29 June 1971. The mission ended in disaster when the crew capsule depressurised during preparations for re-entry, killing the three-man crew. The three crew members of Soyuz 11 are the only humans to have died in space.
  • 3.3K
  • 09 Oct 2022
Topic Review
Cyanomethylation Reaction
Cyanomethylation is very useful in organic synthesis because the cyano groups can be hydrolyzed to carboxylic acids and reduced to amines, from which other functional groups can be derived. In addition, the cyano group is the structural unit of many drugs, such as piritramide, diphenozlate, and gallopamil, while acetonitrile is an ideal source of the cyanomethyl functional group due to the difficulty in breaking the C-CN bond. 
  • 3.3K
  • 08 May 2023
Topic Review
Histopathology of Choroidal Melanoma
Choroidal melanoma (CM), despite its rarity, is the most frequent intraocular malignancy. Over time, several histological variants of CM have been distinguished, including spindle A and B cell, fascicular, epithelioid and necrotic type. However, they have been progressively abandoned as having no prognostic value and currently, the American Joint Committee of Cancer (AJCC) classification identifies three CM cell types: spindle, epithelioid and mixed cell type. Other rare histological variants of CM include: (i) diffuse melanoma; (ii) clear cell; and (iii) balloon cell melanoma. Immunohistochemically, CMs are stained with Human Melanoma Black 45 (HMB45) antigen, S-100 protein, Melan-A (also known as melanoma antigen recognized by T cells 1/MART-1), melanocyte inducing transcription factor (MITF), tyrosinase, vimentin, and Sex determining region Y-Box 10 (SOX10). Several genetic and histopathological prognostic factors of CM have been reported in the literature, including epithelioid cell type, TNM staging, extraocular extension, monosomy 3 and 6p gain and loss of BAP-1 gene. The aim of this review was to summarize the histopathological, immunohistochemical and genetic features of CM, establishing “the state of the art” and providing colleagues with practical tools to promptly deal with patients affected by this rare malignant neoplasm.
  • 3.3K
  • 17 Dec 2020
Topic Review
Malaria
Malaria is a severe disease caused by parasites of the genus Plasmodium, which is transmitted to humans by a bite of an infected female mosquito of the species Anopheles. Malaria remains the leading cause of mortality around the world, and early diagnosis and fast-acting treatment prevent unwanted outcomes. It is the most common disease in Africa and some countries of Asia, while in the developed world malaria occurs as imported from endemic areas. The sweet sagewort plant was used as early as the second century BC to treat malaria fever in China. Much later, quinine started being used as an antimalaria drug. A global battle against malaria started in 1955. The World Health Organization carries out a malaria control program on a global scale, focusing on local strengthening of primary health care, early diagnosis of the disease, timely treatment, and disease prevention. Globally, the burden of malaria is lower than ten years ago. However, in the last few years, there has been an increase in the number of malaria cases around the world. It is moving towards targets established by the WHO, but that progress has slowed down.
  • 3.3K
  • 17 Feb 2021
Topic Review
Vitamin C Deficiency
Vitamin C is an essential nutrient that must be obtained through the diet in adequate amounts to prevent hypovitaminosis C, deficiency and its consequences—including the potentially fatal deficiency disease scurvy. Global vitamin C status and prevalence of deficiency has not previously been reported, despite vitamin C’s pleiotropic roles in both non-communicable and communicable disease. This entry highlights the global literature on vitamin C status and the prevalence of hypovitaminosis C and deficiency. Related dietary intake is reported if assessed in the studies. Overall, the entry illustrates the shortage of high quality epidemiological studies of vitamin C status in many countries, particularly low- and middle-income countries. The available evidence indicates that vitamin C hypovitaminosis and deficiency is common in low- and middle-income countries and not uncommon in high income settings. 
  • 3.3K
  • 27 Jul 2020
Topic Review
Nucleation in Polymer Crystallization
Nucleation plays a vital role in polymer crystallization, in which chain connectivity and thus the multiple length and time scales make crystal nucleation of polymer chains an interesting but complex subject. Though the topic has been intensively studied in the past decades, there are still many open questions to answer. The final properties of semicrystalline polymer materials are affected by all of the following: the starting melt, paths of nucleation, organization of lamellar crystals and evolution of the final crystalline structures. In this viewpoint, we attempt to discuss some of the remaining open questions and corresponding concepts: non-equilibrated polymers, self-induced nucleation, microscopic kinetics of different processes, metastability of polymer lamellar crystals, hierarchical order and cooperativity involved in nucleation, etc. Addressing these open questions through a combination of novel concepts, new theories and advanced approaches provides a deeper understanding of the multifaceted process of crystal nucleation of polymers.
  • 3.3K
  • 25 Jun 2021
Topic Review
The Impact of Chatbots on Customer Loyalty
More and more companies have implemented chatbots on their websites to provide support to their visitors on a 24/7 basis. The new customer wants to spend less and less time and therefore expects to reach a company anytime and anywhere, regardless of time, location, and channel. System quality, service quality, and information quality are crucial dimensions that a chatbot must meet to give a good customer experience. To make a chatbot more personal, companies can alter the language style. Human-like chatbots lead to greater satisfaction and trust among customers, leading to greater adoption of the chatbot. A connection between chatbots and customer loyalty is very likely. Besides, some customers suffer from the privacy paradox because of personalization.
  • 3.3K
  • 07 Mar 2022
Topic Review Peer Reviewed
Otovestibular Symptoms of COVID-19 and Its Vaccines/Treatments
The rapidly developing literature regarding COVID-19 and its treatments has documented an impressive breadth of pathology across multiple organ systems. In this entry, researchers highlight the audiologic and vestibular manifestations that have been reported in association with COVID-19, its vaccines, and some of its treatments.
  • 3.3K
  • 08 Jul 2022
Topic Review
China’s Inclusive Education Legislation, Law, and Policy
Laws and policies, no matter how well designed, can fail if they are not implemented correctly. This can occur when there is no interaction between policymakers and those who are working on the ground.
  • 3.3K
  • 30 Jun 2023
  • Page
  • of
  • 2727
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