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Topic Review
Flow Battery
A flow battery, or redox flow battery (after reduction–oxidation), is a type of electrochemical cell where chemical energy is provided by two chemical components dissolved in liquids that are pumped through the system on separate sides of a membrane. Ion exchange (accompanied by flow of electric current) occurs through the membrane while both liquids circulate in their own respective space. Cell voltage is chemically determined by the Nernst equation and ranges, in practical applications, from 1.0 to 2.43 volts. A flow battery may be used like a fuel cell (where the spent fuel is extracted and new fuel is added to the system) or like a rechargeable battery (where an electric power source drives regeneration of the fuel). While it has technical advantages over conventional rechargeables, such as potentially separable liquid tanks and near unlimited longevity, current implementations are comparatively less powerful and require more sophisticated electronics. The energy capacity is a function of the electrolyte volume and the power is a function of the surface area of the electrodes.
  • 2.3K
  • 12 Oct 2022
Topic Review
Human-Computer Interaction System of Talking-Head Generation
Virtual human is widely employed in various industries, including personal assistance, intelligent customer service, and online education, thanks to the rapid development of artificial intelligence. An anthropomorphic digital human can quickly contact people and enhance user experience in human–computer interaction. 
  • 2.3K
  • 12 Jan 2023
Topic Review
Lactosylceramide
Lactosylceramide (LacCer), also known as CD17/CDw17, is a member of a large family of small molecular weight compounds known as glycosphingolipids. It plays a pivotal role in the biosynthesis of glycosphingolipids, primarily by way of serving as a precursor to the majority of its higher homolog sub-families such as gangliosides, sulfatides, fucosylated-glycosphingolipids and complex neutral glycosphingolipids—some of which confer “second-messenger” and receptor functions. LacCer is an integral component of the “lipid rafts,” serving as a conduit to transduce external stimuli into multiple phenotypes, which may contribute to mortality and morbidity in man and in mouse models of human disease.
  • 2.3K
  • 02 Mar 2021
Topic Review
AFM imaging of extracellular vesicles
Advanced and optimised microscopy methods, including atomic force microscopy (AFM), are required to visualise and characterise morphology of extracellular vesicles (EVs), a heterogenous groups of nanoparticles regarded as highly promising source of diagnostic, prognostic, and therapeutic tools. EVs are nanosized phospholipid membranous structures ubiquitously found in human biofluids, secreted from almost every cell, and thus reflect both physiological and pathophysiological changes of their parental cells. The lipid membrane of an EV contains proteins (e.g., tetraspanins, receptors and other molecules) and diverse luminal content with bioactive cargo that includes nucleic acids (DNA, mRNA, miRNA and lncRNA), proteins, organelles, or infectious particles.  AFM is a nanoscale tool for the determination of morphology, structure and composition, but also biomechanics and biophysical characteristics of nanometric structures. Briefly, AFM uses a micrometric cantilever with a nanometre-sized tip actuated by piezoelectric crystals. Upon receiving signals of a tip-sample interaction, a position-sensitive photodiode (PSPD) converts it to a voltage and sends it to a piezoelectric actuator (PA). The latter expands and contracts proportionally to the applied voltage to manipulate the sample and the probe position across three dimensions with high precision. The PA can be coupled to a cantilever or positioned under a sample holder. The whole system is controlled by suitable control electronics.
  • 2.3K
  • 11 Oct 2021
Topic Review
Computational Drug Design of TB
Developing new, more effective antibiotics against resistant Mycobacterium tuberculosis that inhibit its essential proteins is an appealing strategy for combating the global tuberculosis (TB) epidemic. Finding a compound that can target a particular cavity in a protein and interrupt its enzymatic activity is the crucial objective of drug design and discovery. Such a compound is then subjected to different tests, including clinical trials, to study its effectiveness against the pathogen in the host. In recent times, new techniques, which involve computational and analytical methods, enhanced the chances of drug development, as opposed to traditional drug design methods, which are laborious and time-consuming. The computational techniques in drug design have been improved with a new generation of software used to develop and optimize active compounds that can be used in future chemotherapeutic development to combat global tuberculosis resistance.
  • 2.3K
  • 17 Dec 2021
Topic Review
Effects of Environmental Changes in the Amazon Region
Environmental changes caused by human activities alter the water, energy, and carbon cycles in the Amazon region. This has resulted in biological changes across several plant species, some of which are used in both regional and global trade and represent important sources of food and income for people. Reports from local people and scientific studies point to the effects of deforestation, forest degradation, and climate change on native plant species. Indeed, people who are typically dependent on natural resources and ecosystem services are the most threatened by plant species productivity and geographical distribution changes. However, there is a lack of scientific literature concerning the effects of environmental changes on plant species and forest-dependent communities in the Amazon region.
  • 2.3K
  • 28 Mar 2022
Topic Review
Ecological Succession Theory
In addition to states of space that are supposedly to be aspired to or maintained, which are often the subject of heated, acrimonious debates, there are temporary states of equilibrium in time that mirror the overarching cycle of life, have been the subject of research for a very long time, and are well documented and conceptually understood: namely, ecological succession. The knowledge and understanding of succession is irreplaceable to have a chance today to ground and resolve such mentioned debates about multiple claims and uses of spaces nowadays. For example, a main challenge of the current time is that large areas of land are needed for renewable energy production, and production sites should be designed to include biodiversity preservation. Decision-makers need guidance for reasonable coexistence. Succession theory can indeed provide substantial background and guidance.
  • 2.3K
  • 27 Jun 2022
Topic Review
Annealing (Metallurgy)
In metallurgy and materials science, annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material above its recrystallization temperature, maintaining a suitable temperature for an appropriate amount of time and then cooling. In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to a change in ductility and hardness. As the material cools it recrystallizes. For many alloys, including carbon steel, the crystal grain size and phase composition, which ultimately determine the material properties, are dependent on the heating rate and cooling rate. Hot working or cold working after the annealing process alters the metal structure, so further heat treatments may be used to achieve the properties required. With knowledge of the composition and phase diagram, heat treatment can be used to adjust from harder and more brittle to softer and more ductile. In the case of ferrous metals, such as steel, annealing is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air. Copper, silver and brass can be either cooled slowly in air, or quickly by quenching in water. In this fashion, the metal is softened and prepared for further work such as shaping, stamping, or forming.
  • 2.3K
  • 09 Oct 2022
Topic Review
Homomorphic Encryption for Privacy-Preserving Biometrics
The advancement of biometric technology has facilitated wide applications of biometrics in law enforcement, border control, healthcare and financial identification and verification. Given the peculiarity of biometric features (e.g., unchangeability, permanence and uniqueness), the security of biometric data is a key area of research. Security and privacy are vital to enacting integrity, reliability and availability in biometric-related applications. Homomorphic encryption (HE) is concerned with data manipulation in the cryptographic domain, thus addressing the security and privacy issues faced by biometrics.
  • 2.3K
  • 16 Jun 2023
Topic Review
Material Extrusion Troubleshooting
      Material Extrusion (ME) offers end-users a more affordable and accessible Additive Manufacturing (AM) technology in contrast to other processes. ME is frequently used to quickly produce low-cost prototypes with the freedom of scalability where parts can be produced in various geometries, quantities and sizes. This article provides guidelines and advice for end-users to identify and efficiently troubleshoot issues concerning desktop ME processes quickly. The systemic issues and solutions covered include three categories: printer-related, deposition-related and quality problems. The majority of issues encountered in ME are associated with incorrect printer calibration and parameters, hardware, material, Computer-Aided Design (CAD) model and/or slicing errors. A troubleshooting chart for ME is presented that allows designers and engineers to determine the possible contributing factors for a particular problem in an efficient manner.
  • 2.3K
  • 30 Oct 2020
Topic Review
DHA and AA: Neuroprotective Nutrient
The role of docosahexaenoic acid (DHA) and arachidonic acid (AA) in neurogenesis and brain development throughout the life cycle is fundamental. DHA and AA are long-chain polyunsaturated fatty acids (LCPUFA) vital for many human physiological processes, such as signaling pathways, gene expression, structure and function of membranes, among others. DHA and AA are deposited into the lipids of cell membranes that form the gray matter representing approximately 25% of the total content of brain fatty acids. Both fatty acids have effects on neuronal growth and differentiation through the modulation of the physical properties of neuronal membranes, signal transduction associated with G proteins, and gene expression. DHA and AA have a relevant role in neuroprotection against neurodegenerative pathologies such as Alzheimer’s disease and Parkinson’s disease, which are associated with characteristic pathological expressions as mitochondrial dysfunction, neuroinflammation, and oxidative stress. 
  • 2.3K
  • 31 Mar 2021
Topic Review
An Overview of PDE4 Inhibitors in Clinical Trials
Since the early 1980s, phosphodiesterase 4 (PDE4) has been an attractive target for the treatment of inflammation-based diseases. Several scientific advancements, by both academia and pharmaceutical companies, have enabled the identification of many synthetic ligands for this target, along with the acquisition of precise information on biological requirements and linked therapeutic opportunities. The transition from pre-clinical to clinical phase was not easy for the majority of these compounds, mainly due to their significant side effects, and it took almost thirty years for a PDE4 inhibitor to become a drug i.e., Roflumilast, used in the clinics for the treatment of chronic obstructive pulmonary disease. Three additional compounds have reached the market: Crisaborole for atopic dermatitis, Apremilast for psoriatic arthritis and Ibudilast for Krabbe disease. 
  • 2.3K
  • 31 Aug 2022
Topic Review
Quinces as Medicinal Fruits of the Rosaceae Family
Quince (Cydonia oblonga, Chaenomeles sp., and Pseuocydonia sinensis) fruits contain carotenoids, vitamins, minerals, carboxylic acids, triterpenes, and bioactive polyphenols. They are rich in antioxidants and chemical compounds that have demonstrated anti-inflammatory, anticancer, anti-allergic, and immunomodulatory effects. Their phytochemicals have been shown to effectively regulate glycemia and improve blood lipid profiles, suggesting potential anti-diabetic and cardioprotective benefits. The fruits of the Cydonia, Chaenomeles, and Pseuocydonia genera are morpholophically similar, which may make them difficult to distinguish.
  • 2.3K
  • 16 Jan 2024
Topic Review
Poplar-Type Propolis
Propolis is a resinous mixture, made by the honeybees from substances collected from tree or other plant buds, plant exudates, or resins found in the stem, branches, or leaves of different plants. 
  • 2.3K
  • 18 Jan 2021
Topic Review
Silver Nanoparticle
Silver nanoparticles (AgNPs) are among the most commonly used engineered nanomaterials with medicinal, industrial, and agricultural applications. Considering the vast usage of AgNPs, there is a possibility of their release into the environment, and their potential toxicological effects on plants and animals. Apart from using the particulate form of silver, AgNPs may be transformed to silver oxide or silver sulfide via oxidation or sulfidation, respectively, and these ones impact the soil and living organisms in a variety of ways. Therefore, it is critical to address the behavior of nanoparticles in the environment and possible methods for their removal. This review focuses on three objectives to discuss this issue including: the possible pathways for the release of AgNPs into the environment; the toxicological effects of AgNPs on plants and microorganisms; and the recommended phytoremediation approaches.
  • 2.3K
  • 19 Oct 2021
Topic Review
Health Effects of Sweet Potato (Ipomoea batatas L.)
Sweet potato (SP; Ipomoea batatas (L.) Lam) is an edible tuber native to America and the sixth most important food crop worldwide. China leads its production in a global market of USD 45 trillion. SP domesticated varieties differ in specific phenotypic/genotypic traits, yet all of them are rich in sugars, slow digestible/resistant starch, vitamins, minerals, bioactive proteins and lipids, carotenoids, polyphenols, ascorbic acid, alkaloids, coumarins, and saponins, in a genotype-dependent manner. Individually or synergistically, SP’s phytochemicals help to prevent many illnesses, including certain types of cancers and cardiovascular disorders.
  • 2.3K
  • 18 Apr 2022
Topic Review
Clean Development Mechanism
The Clean Development Mechanism (CDM) is one of the Flexible Mechanisms defined in the Kyoto Protocol (IPCC, 2007) that provides for emissions reduction projects which generate Certified Emission Reduction units (CERs) which may be traded in emissions trading schemes. The market crashed in 2012 when the value of credits collapsed and thousands of projects were left with unclaimed credits. The struggle about what to do with the old credits sank the 2019 COP 25 in Madrid. The CDM, defined in Article 12 of the Protocol, was intended to meet two objectives: "Annex I" parties are the countries listed in Annex I of the treaty, the industrialized countries. Non-Annex I parties are developing countries. The CDM addresses the second objective by allowing the Annex I countries to meet part of their emission reduction commitments under the Kyoto Protocol by buying Certified Emission Reduction units from CDM emission reduction projects in developing countries. Both the projects and the issue of CERs units are subject to approval to ensure that these emission reductions are real and "additional." The CDM is supervised by the CDM Executive Board (CDM EB) under the guidance of the Conference of the Parties (COP/MOP) of the United Nations Framework Convention on Climate Change (UNFCCC). The CDM allows industrialized countries to buy CERs and to invest in emission reductions where it is cheapest globally. Between 2001, which was the first year CDM projects could be registered and 7 September 2012, the CDM issued 1 billion Certified Emission Reduction units. As of 1 June 2013, 57% of all CERs had been issued for projects based on destroying either HFC-23 (38%) or N2O (19%). Carbon capture and storage (CCS) was included in the CDM carbon offsetting scheme in December 2011. However, a number of weaknesses of the CDM have been identified. Several of these issues were addressed by the new Program of Activities (PoA), which moves to approving 'bundles' of projects instead of accrediting each project individually. In 2012, the report Climate Change, Carbon Markets and the CDM: A Call to Action said governments urgently needed to address the future of the CDM. It suggested the CDM was in danger of collapse because of the low price of carbon and the failure of governments to guarantee its existence into the future. Writing on the website of the Climate & Development Knowledge Network, Yolanda Kakabadse, a member of the investigating panel for the report and founder of Fundación Futuro Latinamericano, said a strong CDM is needed to support the political consensus essential for future climate progress. "Therefore we must do everything in our hands to keep it working," she said.
  • 2.3K
  • 17 Oct 2022
Topic Review
Mercedes-Benz OM138 Engine
The Mercedes-Benz OM 138 is a diesel engine manufactured by Daimler-Benz: 5,719 were produced between 1935 and 1940[A 1] It was the first diesel engine especially developed and made for a passenger car. The first vehicle powered by the OM 138 was the Mercedes-Benz W 138. The light Mercedes-Benz trucks L 1100 and L 1500 as well as the bus O 1500[A 2] were also offered with the OM 138 as an alternative to an otto engine.
  • 2.3K
  • 24 Oct 2022
Topic Review
Smith Electric Vehicles
Smith Electric Vehicles (also known as Smith's) was a manufacturer of electric trucks. The company, founded in 1920 in the north of England, moved its headquarters to Kansas City, Missouri in 2011. In 2015, Smith idled its manufacturing and it ceased all operations in 2017. Smith was a manufacturer of the world's largest range of zero-emission commercial electric vehicles, with gross vehicle weights (GVWs) from 3,500 to 12,000 kilograms (7,700 to 26,500 lb). From 2010 to 2015, the company produced over 800 commercial electric fleet vehicles. Formerly based in Washington, Tyne and Wear, it manufactured vehicles for the European, Canadian, Southeast Asian and US markets. Smith was formerly part of the Tanfield Group, which trades on the London Stock Exchange's Alternative Investment Market. Tanfield established a Delaware corporation, Smith Electric Vehicles US Corp (SEV US Corp), in 2009 to penetrate the North American market. The company headquarters is in Kansas City, Missouri. In March 2010, the US company indicated that it wanted to buy out its UK counterpart. After a poor multi-year trading history, Smith's UK branches were shut down. This included Smith Electric Vehicles (Europe), which was put into administration, and Smith Technologies (which entered liquidation).
  • 2.3K
  • 02 Nov 2022
Topic Review
Social Login
Social login is a form of single sign-on using existing information from a social networking service such as Facebook, Twitter or Google, to sign into a third party website instead of creating a new login account specifically for that website. It is designed to simplify logins for end users as well as provide more and more reliable demographic information to web developers.
  • 2.3K
  • 03 Nov 2022
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