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Topic Review
Cyanidin-3-Glucoside
Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin and possesses antioxidant and anti-inflammatory properties. The catabolism of C3G in the gastrointestinal tract could produce bioactive phenolic metabolites, such as protocatechuic acid, phloroglucinaldehyde, vanillic acid, and ferulic acid, which enhance C3G bioavailability and contribute to both mucosal barrier and microbiota.
  • 3.1K
  • 02 Aug 2021
Topic Review
T Lymphocyte
Exosomes are extracellular vesicles (EV) of endosomal origin (multivesicular bodies, MVB) constitutively released by many different eukaryotic cells by fusion of MVB to the plasma membrane. However, inducible exosome secretion controlled by cell surface receptors is restricted to very few cell types and a limited number of cell surface receptors. Among these, exosome secretion is induced in T lymphocytes and B lymphocytes when stimulated at the immune synapse (IS) via T-cell receptor (TCR) and B-cell receptor (BCR), respectively. IS formation by T and B lymphocytes constitutes a crucial event involved in antigen-specific, cellular and humoral immune responses. Upon IS formation by T and B lymphocytes with antigen-presenting cells (APC) the convergence of MVB towards the microtubule organization center (MTOC), and MTOC polarization to the IS, are involved in polarized exosome secretion at the synaptic cleft. This specialized mechanism provides the immune system with a finely-tuned strategy to increase the specificity and efficiency of crucial secretory effector functions of B and T lymphocytes. Since inducible exosome secretion by antigen-receptors is a critical and unique feature of the immune system this entry considers the study of the traffic events leading to polarized exosome secretion at the IS and some of their biological consequences.
  • 3.1K
  • 29 Oct 2020
Topic Review
Applications of Lignin in Wood
Lignin is the most abundant aromatic polymer in nature and the second most abundant biomass on earth. In paper production and other processes, lignin is obtained as a side product and mainly used energetically. The use of lignin in wood adhesives or for wood modification has received a lot of scientific attention.
  • 3.1K
  • 25 May 2021
Topic Review
Fluid Reaction Models
In the fluidized bed system, the performance of the reactor is affected by the hydrodynamic behaviors of the reactor in that fluid dynamics affects both heat and mass transfer.
  • 3.1K
  • 28 Jul 2021
Topic Review
Localization of a Ring
In commutative algebra, localization is a systematic method of adding multiplicative inverses to a ring. Given a ring R and a subset S, one wants to construct some ring R* and ring homomorphism from R to R*, such that the image of S consists of units (invertible elements) in R*. Further one wants R* to be the 'best possible' or 'most general' way to do this—in the usual fashion this should be expressed by a universal property. The localization of R by S is usually denoted by S −1R; however other notations are used in some important special cases. If S is the set of the non zero elements of an integral domain, then the localization is the field of fractions and thus usually denoted Frac(R). If S is the complement of a prime ideal I the localization is denoted by RI, and Rf is used to denote the localization by the powers of an element f. The two latter cases are fundamental in algebraic geometry and scheme theory. In particular the definition of an affine scheme is based on the properties of these two kinds of localizations.
  • 3.1K
  • 26 Oct 2022
Topic Review
Halitosis
Halitosis, also known as fetor ex ore, bad breath or oral malodor, is a common disorder meaning unpleasant smell from the mouth. Halitosis is a common problem that manifests as an unpleasant and disgusting odor emanating from the mouth[1]. Malodor is mainly caused by putrefactive actions of microorganisms on endogenous or exogenous proteins and peptides. Oral malodor is an embarrassing condition that affects a large percentage of the human population. This condition often results in nervousness, humiliation, and social difficulties, such as the inability to approach people and speak to them[2][3][4][5][6].
  • 3.1K
  • 11 Sep 2020
Topic Review
Lifshitz Theory of Van Der Waals Force
In condensed matter physics and physical chemistry, the Lifshitz theory of van der Waals forces, sometimes called the macroscopic theory of van der Waals forces, is a method proposed by Evgeny Mikhailovich Lifshitz in 1954 for treating van der Waals forces between bodies which does not assume pairwise additivity of the individual intermolecular forces; that is to say, the theory takes into account the influence of neighboring molecules on the interaction between every pair of molecules located in the two bodies, rather than treating each pair independently.
  • 3.1K
  • 03 Nov 2022
Topic Review
Thermal Denaturation of Milk Whey Proteins: Rapid Quantification
Heat treatment of milk signifies a certain degree of protein denaturation, which modifies the functional properties of dairy products. Traditional methods for detecting and quantifying the denaturation of whey proteins are slow, complex and require sample preparation and qualified staff. The world’s current trend is to develop rapid, real-time analytical methods that do not destroy the sample and can be applied on/in-line during processing.
  • 3.1K
  • 03 Aug 2022
Topic Review
Characteristics of Vitamin E
Vitamin E is a fat-soluble organic micronutrient that helps to preserve human health. Its main function is likely that of a radical scavenger protecting biological membranes from lipid peroxidation. Vegetable oils, such as wheat germ, sunflower, corn germ, soybean, and rapeseed, are the primary dietary source of vitamin E for humans. It is also found in some nuts, fruits, and vegetables, such as almonds, avocados, spinach, and kale.
  • 3.1K
  • 16 Sep 2022
Topic Review
Quantum Dot-Based Lateral Flow Immunoassay
Point-of-care testing (POCT) technology has exhibited an outstanding capability for the detection of several disease biomarkers owing to the fact that such techniques are fast, easy to perform, efficient, and low cost. The lateral flow immunoassay (LFIA) is one such strategy for POCT. LFIA is a well-established platform and a potent assay for fast and inexpensive testing, as this technology is instrumentation independent and allows the visualisation of test results by the naked eye. In order to enhance the sensitivity and specificity of the LFIAs, as well as to allow the quantitation of results, fluorescence immunochromatographic assays have been developed by utilising fluorescent reporters. Fluorescence immunochromatographic assays have advantages over conventional approaches in regard to sensitivity as it produces a higher intensity band on the test and control lines. One such promising fluorescent reporter is quantum dots (QDs). QDs are tiny semiconducting nanocrystals with diameters ranging from 2 to 10 nanometers. QDs have unique electronic characteristics that are intermediate between those of bulk semiconductors and discrete molecules, which is due in part to their high surface-to-volume ratios. The most visible result is fluorescence, in which the nanocrystals emit distinct colours determined by particle size.
  • 3.1K
  • 19 Sep 2022
Topic Review
Negative-Sense Single-Stranded RNA Viral Factories
Liquid–liquid phase separation (LLPS) represents a major physiochemical principle to organize intracellular membrane-less structures. Studies with non-segmented negative-sense (NNS) RNA viruses have uncovered a key role of LLPS in the formation of viral inclusion bodies (IBs), sites of viral protein concentration in the cytoplasm of infected cells. These studies further reveal the structural and functional complexity of viral IB factories as liquid-like organelles and sites of viral replication.
  • 3.1K
  • 29 Jan 2021
Topic Review
Premature Ovarian Insufficiency and Infertility
Reproductive aging is on the rise globally and inseparable from the entire aging process. An extreme form of reproductive aging is premature ovarian insufficiency (POI), which to date has mostly been of idiopathic etiology, thus hampering further clinical applications and associated with enormous socioeconomic and personal costs. In the field of reproduction, timely diagnosis with a clear understanding of the various comorbidities that can arise from estrogen deficiency and the important functional role of inflammation-induced ovarian deterioration are research hotspots for appropriate counseling and preventing this prematurely ovarian aging disease. It is evident that more research is required to allow pre-emptive identification of the at-risk population and to identify mechanisms that, if addressed promptly, can prolong ovarian function and fertility.
  • 3.1K
  • 30 Dec 2022
Topic Review
E-Bike Sharing System
Recent data on conventional bike and/or electric bike (e-bike) sharing systems reveal that more than 2900 systems are operating in cities worldwide, indicating the increased adoption of this alternative mode of transportation. Addressing the existing gap in the literature regarding the deployment of e-bike sharing systems (e-BSSs) in particular, this paper reviews their spatio-temporal characteristics, and attempts to (a) map the worldwide distribution of e-BSSs, (b) identify temporal trends in terms of annual growth/expansion of e-BSS deployment worldwide and (c) explore the spatial characteristics of the recorded growth, in terms of adoption on a country scale, population coverage and type of system/initial fleet sizes. To that end, it examines the patterns identified from the global to the country level, based on data collected from an online source of BSS information worldwide. A comparative analysis is performed with a focus on Europe, North America and Asia, providing insights on the growth rate of the specific bikesharing market segment. Although the dockless e-BSS has been only within three years of competition with station-based implementations, it shows a rapid integration to the overall technology diffusion trend, while it is more established in Asia and North America in comparison with Europe and launches with larger fleet sizes.
  • 3.1K
  • 27 Oct 2020
Topic Review Peer Reviewed
SARS, MERS and COVID-19-Associated Renal Pathology
Coronaviruses are a large group of RNA viruses, the most notable representatives of which are SARS-CoV, MERS-CoV and SARS-CoV-2. Human coronavirus infections were first documented in the 1960s, when members causing seasonal common colds were successfully replicated in human embryonal trachea and kidney cell cultures and classified based on electron microscopy. The history of coronaviruses stretched far back to that point, however, with some representatives causing disease in animals identified several decades prior and evolutionary data pointing towards the origin of this viral group more than 55 million years ago. In the short time period of research since they were discovered, coronaviruses have shown significant diversity, genetic peculiarities and varying tropism, resulting in the three identified causative agents of severe disease in humans—SARS, MERS and the most recent one, COVID-19, which has surpassed the previous two due to causing a pandemic resulting in significant healthcare, social and political consequences. Coronaviruses are likely to have caused pandemics long before, such as the so-called Asian or Russian influenza. Despite being epitheliotropic viruses and predominantly affecting the respiratory system, these entities affect multiple systems and organs, including the kidneys. In the kidneys, they actively replicate in glomerular podocytes and epithelial cells of the tubules, resulting in acute kidney injury, seen in a significant percentage of severe and fatal cases. Furthermore, the endothelial affinity of the viruses, resulting in endotheliitis, increases the likelihood of thrombotic microangiopathy, damaging the kidneys in a two-hit mechanism. As such, recently, COVAN has been a suggested nomenclature change indicating renal involvement in coronavirus infections and its long-lasting consequences. 
  • 3.1K
  • 10 Oct 2022
Topic Review
Removal of Confederate Monuments and Memorials
For decades in the U.S., there have been isolated incidents of removal of Confederate monuments and memorials, although generally opposed in public opinion polls, and several U.S. States have passed laws over 115 years to hinder or prohibit further removals. In the wake of the Charleston church shooting in June 2015, several municipalities in the United States removed monuments and memorials on public property dedicated to the Confederate States of America. The momentum accelerated in August 2017 after the Unite the Right rally in Charlottesville, Virginia. The removals were driven by the belief that the monuments glorify white supremacy and memorialize a government whose founding principle was the perpetuation and expansion of slavery. Many of those who object to the removals, like President Trump, claim that the artifacts are part of the cultural heritage of the United States. Detractors claim that the vast majority of these Confederate monuments were built during the era of Jim Crow (1877–1954) and the Civil Rights Movement (1954–1968) not as memorials but as a means of intimidating African Americans and reaffirming white supremacy. The monuments have thus become highly politicized; according to Eleanor Harvey, a senior curator at the Smithsonian American Art Museum and a scholar of Civil War history: "If white nationalists and neo-Nazis are now claiming this as part of their heritage, they have essentially co-opted those images and those statues beyond any capacity to neutralize them again". Civil War historian James I. Robertson Jr. referred to the current climate to dismantle or destroy Confederate monuments as an "age of idiocy" and motivated by "elements hell-bent on tearing apart unity that generations of Americans have painfully constructed" and the monuments were not a "Jim Crow signal of defiance." In some Southern states, state law restricts or prohibits altogether the removal or alteration of public Confederate monuments. According to Stan Deaton, senior historian at the Georgia Historical Society, "These laws are the Old South imposing its moral and its political views on us forever more. This is what led to the Civil War, and it still divides us as a country. We have competing visions not only about the future but about the past." As Southern novelist William Faulkner famously put it, in the American South "the past is never dead. It's not even past."
  • 3.1K
  • 30 Nov 2022
Topic Review
Short Text Clustering Algorithms
Short text clustering (STC) has become a critical task for automatically grouping various unlabelled texts into meaningful clusters. STC is a necessary step in many applications, including Twitter personalization, sentiment analysis, spam filtering, customer reviews and many other social network-related applications.
  • 3.1K
  • 18 Jan 2023
Topic Review
Gent (Hyperelastic Model)
The Gent hyperelastic material model is a phenomenological model of rubber elasticity that is based on the concept of limiting chain extensibility. In this model, the strain energy density function is designed such that it has a singularity when the first invariant of the left Cauchy-Green deformation tensor reaches a limiting value [math]\displaystyle{ I_m }[/math]. The strain energy density function for the Gent model is where [math]\displaystyle{ \mu }[/math] is the shear modulus and [math]\displaystyle{ J_m = I_m -3 }[/math]. In the limit where [math]\displaystyle{ I_m \rightarrow \infty }[/math], the Gent model reduces to the Neo-Hookean solid model. This can be seen by expressing the Gent model in the form A Taylor series expansion of [math]\displaystyle{ \ln\left[1 - (I_1-3)x\right] }[/math] around [math]\displaystyle{ x = 0 }[/math] and taking the limit as [math]\displaystyle{ x\rightarrow 0 }[/math] leads to which is the expression for the strain energy density of a Neo-Hookean solid. Several compressible versions of the Gent model have been designed. One such model has the form (the below strain energy function yields a non zero hydrostatic stress at no deformation, refer https://link.springer.com/article/10.1007/s10659-005-4408-x for compressible Gent models). where [math]\displaystyle{ J = \det(\boldsymbol{F}) }[/math], [math]\displaystyle{ \kappa }[/math] is the bulk modulus, and [math]\displaystyle{ \boldsymbol{F} }[/math] is the deformation gradient.
  • 3.1K
  • 21 Nov 2022
Topic Review
Varangian Guard
The Varangian Guard (Greek: Τάγμα τῶν Βαράγγων, Tágma tōn Varángōn) was an elite unit of the Byzantine Army, from the 10th to the 14th centuries, whose members served as personal bodyguards to the Byzantine Emperors. They are known for being primarily composed of Germanic peoples, specifically Norsemen from modern day Sweden (the Guard was formed approximately 200 years into the Viking Age) and Anglo-Saxons (after the Norman Conquest of England created an Anglo-Saxon diaspora, part of which found employment in Constantinople). The Rus' provided the earliest members of the Varangian Guard. They were in Byzantine service from as early as 874. The Guard was first formally constituted under Emperor Basil II in 988, following the Christianization of Kievan Rus' by Vladimir I of Kiev. Vladimir, who had recently usurped power in Kiev with an army of Varangian warriors, sent 6,000 men to Basil as part of a military assistance agreement. Basil's distrust of the native Byzantine guardsmen, whose loyalties often shifted, with fatal consequences, as well as the proven loyalty of the Varangians, many of whom had previously served in Byzantium, led the Emperor to employ them as his personal guardsmen. Immigrants from Sweden, Denmark , Norway and Iceland kept a predominantly Norse cast to the organization until the late 11th century. According to the late Swedish historian Alf Henrikson in his book Svensk Historia (History of Sweden), the Scandinavian Varangian guardsmen were recognized by long hair, a red ruby set in the left ear and ornamented dragons sewn on their chainmail shirts. In these years, Scandinavian men left to enlist in the Byzantine Varangian Guard in such numbers that a medieval Swedish law, Västergötlagen, from Västergötland declared no one could inherit while staying in "Greece"—the then Scandinavian term for the Byzantine Empire—to stop the emigration, especially as two other European courts simultaneously also recruited Scandinavians: Kievan Rus' c. 980–1060 and London 1018–1066 (the Þingalið). Composed primarily of Norsemen and Rus for the first 100 years, the Guard began to see increased numbers of Anglo-Saxons after the Norman conquest of England. By the time of the Emperor Alexios Komnenos in the late 11th century, the Varangian Guard was largely recruited from Anglo-Saxons and "others who had suffered at the hands of the Vikings and their cousins the Normans". The Anglo-Saxons and other Germanic peoples shared with the Vikings a tradition of faithful (to death if necessary) oath-bound service, and the Norman invasion of England resulted in many fighting men who had lost their lands and former masters and were looking for positions elsewhere. The Varangian Guard not only provided security for the Byzantine emperors, but also participated in many wars, often playing a decisive role, since they were usually deployed at critical moments of a battle. By the late 13th century, Varangians were mostly ethnically assimilated by the Byzantine Greeks, though the Guard remained in existence until at least mid-14th century. In 1400, there were still some people identifying themselves as "Varangians" in Constantinople.
  • 3.1K
  • 04 Nov 2022
Topic Review
Safe Mode (Spacecraft)
Safe mode is an operating mode of a modern unmanned spacecraft during which all non-essential systems are shut down and only essential functions such as thermal management, radio reception and attitude control are active. Safe mode is entered automatically upon the detection of a predefined operating condition or event that may indicate loss of control or damage to the spacecraft. Usually the trigger event is a system failure or detection of operating conditions considered dangerously out of the normal range. Cosmic rays penetrating spacecraft electrical systems can create false signals or commands and thus cause a trigger event. The central processor electronics are especially prone to such events. Another trigger is the lack of a received command within a given time window. Lack of received commands can be caused by hardware failures or mis-programming of the spacecraft, as in the case of the Viking 1 lander. The process of entering safe mode, sometimes referred to as safing, involves a number of immediate physical actions taken to prevent damage or complete loss. Power is removed from non-essential subsystems. Regaining attitude control, if lost, is the highest priority because it is necessary to maintain thermal balance and proper illumination of the solar panels. A tumbling or cartwheeling spacecraft can quickly roast, freeze or exhaust its battery power and be lost forever.
  • 3.1K
  • 02 Nov 2022
Topic Review
Electromigration
Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. The effect is important in applications where high direct current densities are used, such as in microelectronics and related structures. As the structure size in electronics such as integrated circuits (ICs) decreases, the practical significance of this effect increases.
  • 3.1K
  • 24 Nov 2022
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