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
Orange Peel Boards
The Orange Peel Board is a panel made by mixture of different proportions dried peels and wet peels. The commonly used processing method is thermo-pressing.  
  • 3.3K
  • 19 Jul 2021
Topic Review
Cloned Goats
The Cloned Goats or Transgenic Cloned Goats are generated and/or multiplied by one the most advanced and widely applied assisted reproductive technologies (ARTs) designated as somatic cell cloning or somatic cell nuclear transfer (SCNT). The SCNT-derived goats can provide a valuable tool for a variety of transgenic, biomedical, biopharmaceutical and nutri-biotechnological research.
  • 3.3K
  • 21 Jul 2021
Topic Review
Glass Ionomer Cement
The glass ionomer cement (GIC) is a translucent, water-based cement invented in 1972 by Wilson and Kent.
  • 3.3K
  • 30 Nov 2021
Topic Review
Sunscreens and UV Protection
Excessive UV (ultraviolet) radiation exposure is harmful to skin cells since sunburn is accompanied by oxidative burst, leading to a rapid increase in skin cancer. However, the insufficient UV photoprotection of approved sunscreens and the negative impact of their compositions on ecosystems and human health makes the utility of sunscreen a questionable recommendation. Therefore, discovering UV filters with significant antioxidant activity and improved topical performance and photostability is an urgent need.
  • 3.3K
  • 17 Mar 2023
Topic Review
Biomass Pyrolysis
Pyrolysis process has been considered to be an efficient approach for valorization of lignocellulosic biomass into bio-oil and value-added chemicals. Bio-oil refers to biomass pyrolysis liquid, which contains alkanes, aromatic compounds, phenol derivatives, and small amounts of ketone, ester, ether, amine, and alcohol. Lignocellulosic biomass is a renewable and sustainable energy resource for carbon that is readily available in the environment. This review article provides an outline of the pyrolysis process including pretreatment of biomass, pyrolysis mechanism, and process products upgrading. The pretreatment processes for biomass are reviewed including physical and chemical processes. In addition, the gaps in research and recommendations for improving the pretreatment processes are highlighted. Furthermore, the effect of feedstock characterization, operating parameters, and types of biomass on the performance of the pyrolysis process are explained. Recent progress in the identification of the mechanism of the pyrolysis process is addressed with some recommendations for future work. In addition, the article critically provides insight into process upgrading via several approaches specifically using catalytic upgrading. In spite of the current catalytic achievements of catalytic pyrolysis for providing high-quality bio-oil, the production yield has simultaneously dropped. This article explains the current drawbacks of catalytic approaches while suggesting alternative methodologies that could possibly improve the deoxygenation of bio-oil while maintaining high production yield.
  • 3.3K
  • 21 Jul 2020
Topic Review
Compounds of Aluminium
Aluminium (or aluminum) combines characteristics of pre- and post-transition metals. Since it has few available electrons for metallic bonding, like its heavier group 13 congeners, it has the characteristic physical properties of a post-transition metal, with longer-than-expected interatomic distances. Furthermore, as Al3+ is a small and highly charged cation, it is strongly polarizing and aluminium compounds tend towards covalency; this behaviour is similar to that of beryllium (Be2+), an example of a diagonal relationship. However, unlike all other post-transition metals, the underlying core under aluminium's valence shell is that of the preceding noble gas, whereas for gallium and indium it is that of the preceding noble gas plus a filled d-subshell, and for thallium and nihonium it is that of the preceding noble gas plus filled d- and f-subshells. Hence, aluminium does not suffer the effects of incomplete shielding of valence electrons by inner electrons from the nucleus that its heavier congeners do. Aluminium's electropositive behavior, high affinity for oxygen, and highly negative standard electrode potential are all more similar to those of scandium, yttrium, lanthanum, and actinium, which have ds2 configurations of three valence electrons outside a noble gas core: aluminium is the most electropositive metal in its group. Aluminium also bears minor similarities to the metalloid boron in the same group; AlX3 compounds are valence isoelectronic to BX3 compounds (they have the same valence electronic structure), and both behave as Lewis acids and readily form adducts. Additionally, one of the main motifs of boron chemistry is regular icosahedral structures, and aluminium forms an important part of many icosahedral quasicrystal alloys, including the Al–Zn–Mg class.
  • 3.3K
  • 07 Nov 2022
Topic Review
GDM
Gestational diabetes mellitus (GDM) is a pregnancy complication first detected in the second or third trimester in women that did not show evident glucose intolerance or diabetes before gestation. 
  • 3.3K
  • 27 May 2021
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 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
Vitamin B12 Deficiency Anemia
Vitamin B12 deficiency anemia, of which pernicious anemia (PA) is a type, is a disease in which not enough red blood cells are produced due to a deficiency of vitamin B12. The most common initial symptom is feeling tiredness and weakness. Other symptoms may include shortness of breath, pale skin, feeling like one may pass out (lightheadedness), chest pain, rapid heartbeat, numbness in the hands and feet, poor balance, a frequent fall of blood pressure, loss of appetite, a smooth red tongue, memory problems, poor reflexes, and in severe cases even depression and confusion. Without treatment some of these problems may become permanent. Pernicious anemia refers to anemia that results from lack of vitamin B12. Lack of intrinsic factor is most commonly due to an autoimmune attack on the cells that create it in the stomach. It can also occur following the surgical removal of part of the stomach or from an inherited disorder. Other causes of low vitamin B12 include not enough dietary intake (which can be a risk in a vegan diet), celiac disease, or tapeworm infection. When suspected, diagnosis is made by blood and, occasionally, bone marrow tests. Blood tests may show fewer but larger red blood cells, low numbers of young red blood cells, low levels of vitamin B12, and antibodies to intrinsic factor. Pernicious anemia can be treated with injections of vitamin B12. If the symptoms are severe, injections are typically recommended initially. For those who have trouble swallowing pills, a nasal spray is available. Often, treatment is lifelong. Pernicious anemia due to autoimmune problems occurs in about one per 1000 people. Among those over the age of 60, about 2% have the condition. It more commonly affects people of northern European descent. Women are more commonly affected than men. With proper treatment, most people live normal lives. Due to a higher risk of stomach cancer, those with pernicious anemia should be checked regularly for this. The first clear description was by Thomas Addison in 1849. The term "pernicious" means "deadly", and this term came into use because before the availability of treatment the disease was often fatal.
  • 3.3K
  • 27 Oct 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
3D Genome
The genome is the most functional part of a cell, and genomic contents are organized in a compact three-dimensional (3D) structure. The genome contains millions of nucleotide bases organized in its proper frame. Rapid development in genome sequencing and advanced microscopy techniques have enabled us to understand the 3D spatial organization of the genome. Chromosome capture methods using a ligation approach and the visualization tool of a 3D genome browser have facilitated detailed exploration of the genome. 
  • 3.3K
  • 04 Nov 2021
Topic Review
Acquired Cytomegalovirus Infection Hearing Loss
Congenital cytomegalovirus (CMV) infection induces a clinical syndrome usually associated with hearing loss. However, the effect of acquired CVM infection in adults and children has not been clearly defined.
  • 3.3K
  • 28 Dec 2020
Topic Review
Digital Distractions in College Classrooms and Its Impact
University campuses have progressively been equipped with technology. In fact, the presence of technology on university campuses is expected to be increasingly noticeable, as many universities are undergoing digitization processes. Students use many different types of technological devices and software applications during academic activities. Any stimulus or information that diverts an individual’s attention from the main task at hand is considered a distractor. Distractors affect the human ability to concentrate and have an external (noise, movement, etc.) or internal (thoughts, feelings, etc.) origin.
  • 3.3K
  • 29 Nov 2023
Topic Review
Carbon Emission Intensity
The definition of Carbon Emission Intensity (CEI) according to the INDCs is "the amount of carbon dioxide emissions per unit of GDP". As defined, CEI is an emission reduction indicator that takes into account environmental protection and economic development, which has important reference significance for the emission reduction work of developing countries.
  • 3.3K
  • 27 Oct 2020
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
Digital Marketing Utilization Index in Digital Marketing Capability
The digital marketing utilization index (DMUI) measures an organization’s ability to utilize digital marketing to create value for the company through the utilization of the readiness of the innovation ecosystem, digital marketing technology, and digital transformation.
  • 3.3K
  • 06 Sep 2022
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
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
Positive Role of Nanofertilizers on Crop Production
On the basis of the myriad benefits of nanotechnology in agriculture, nanofertilizers (or nanonutrients) have become promising tools for agricultural sustainability. Nanofertilizers are also the proper solution to overcoming the environmental and health problems that can result from conventional fertilizers. The role of nanofertilizers has increased, especially under different environmental stresses, which can include individual, combined, and multiple stresses. The stresses are most commonly the result of nature; however, studies are still needed on the different stress levels. Nanofertilizers can play a crucial role in supporting cultivated plants under stress and in improving the plant yield, both quantitatively and qualitatively.
  • 3.3K
  • 25 Mar 2022
  • 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