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Topic Review

Solid Waste Management in Togo

Waste and resource management in Togo is expected to become more difficult due to increasing socioeconomic development, industrialization, and renewable energy investments. Although there are numerous elements that affect waste and resource management, legislation and policy frameworks are essential.

2.3K
21 Jul 2023

Topic Review

Spectacled Bear

The Spectacled Bear (Tremarctos ornatus) is a distinctive and elusive species native to the Andean region of South America. Renowned for the distinctive facial markings resembling spectacles, this bear is the only surviving bear species in South America and is well-adapted to the diverse habitats of its range, including montane forests, cloud forests, and páramo grasslands. Despite being the smallest bear species in South America, the Spectacled Bear holds significant cultural and ecological importance as a top predator and seed disperser in its high-altitude habitats.

2.3K
08 Mar 2024

Topic Review

Concrete Reinforced with Sisal Fibers

Concrete is a commonly used building material; however, it is subject to abrupt failure and limited energy absorption when yielding. The use of short discrete fibers has displayed a lot of potential in overcoming these issues. Sisal is a natural fiber that is renewable, inexpensive, and readily accessible. SSF is a potential reinforcement for use in concrete because of its cheap cost, low density, high specific strength and modulus, negligible health risk, easy accessibility in certain states, and renewability.

2.3K
12 Aug 2022

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

Developmental Origins of Health and Disease (DOHaD) Hypothesis

The “developmental origins of health and disease” (DOHaD) hypothesis refers to the influence of early developmental exposures and fetal growth on the risk of chronic diseases in later periods.

2.3K
11 Feb 2022

Topic Review

Load Following of Small Modular Reactors

Small modular reactors (SMRs) are generally defined as nuclear reactors with power outputs between 10 megawatts electric (MWe) and 300 MWe. In order to solve such a problem, a load-following operation that adjusts the output of the existing large-capacity thermal power plant or nuclear power plant according to the increase or decrease in the load is required. While this is not technically impossible, it is technically and economically undesirable. The next alternative that comes to mind is a small modular reactor (SMR). This is because, by operating multiple SMRs of less than 300 MW together, as much as necessary, it is easy to carry out a load-following operation, and the safety of an SMR is much higher than that of existing large scale nuclear power plants.

2.3K
07 Sep 2022

Topic Review

Microsoft HoloLens

Microsoft HoloLens, known under development as Project Baraboo, are a pair of mixed reality smartglasses developed and manufactured by Microsoft. HoloLens was the first head-mounted display running the Windows Mixed Reality platform under the Windows 10 computer operating system. The tracking technology used in HoloLens can trace its lineage to Kinect, an add-on for Microsoft's Xbox game console that was introduced in 2010. The pre-production version of HoloLens, the Development Edition, shipped on March 30, 2016, and is targeted to developers in the United States and Canada for a list price of $3000 which allowed hobbyist, professionals, and corporations to participate in the pre-production version of HoloLens. Samsung and Asus have extended an offer to Microsoft to help produce their own mixed-reality products, in collaboration with Microsoft, based around the concept and hardware on HoloLens. On October 12, 2016, Microsoft announced global expansion of HoloLens and publicized that HoloLens would be available for preorder in Australia, Ireland, France, Germany, New Zealand and the United Kingdom. There is also a Commercial Suite (similar to a pro edition of Windows), with enterprise features, such as BitLocker security. As of May 2017, The Suite sold for US$5,000. Microsoft has decided to rent the Hololens without clients making the full investment. Microsoft partners with a company called Abcomrents to give the service of Hololens rental. HoloLens 2 was announced at the Mobile World Congress (MWC) in Barcelona, Spain, on February 24, 2019, and was available on preorder at US$3,500.

2.3K
29 Sep 2022

Topic Review

European Hand Fans in the 18th Century

Hand fans first arrived in Europe in the 15th century from Asia and became popular in the 16th century. Several fan styles were common and a plethora of materials were used to create them. Subject matter varied greatly, from Biblical scenes to landscapes. Hand fans serve as a cooling mechanism, social instrument, and fashion accessory.

2.3K
30 Sep 2022

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 Video

The soil covers our entire planet and corresponds to the most superficial part of the earth's crust. Exposed to the attack of atmospheric agents and living organisms, the soil is organized in layers recognizable to the naked eye, more organic towards the atmosphere or water (if submerged), more mineral towards the rocky part of the bottom. To facilitate its study, specialists divided the soil into three sections: richer in organisms part -> 1. Humipedon; bottom still in contact with the unaltered rock section -> 3. Lithopedon; in-between, central, mineral part -> 2. Copedon. The present encyclopedia entry describes the variability of the humipedons of planet Earth. They have been subdivided in ecological groups and classified into different humus systems. The aim is to display them and diffuse their knowledge.

2.3K
30 Jul 2022

Topic Review

Electric Vehicle Network

An electric vehicle network is an infrastructure system of charging stations and battery swap station to recharge electric vehicles. Many government, car manufacturers, and charging infrastructure providers sought to create networks. (As of December 2016), Estonia remained the only country to have completed a nationwide public electric charging network. (As of 2018) the largest fast-charging location was in Shanghai on the Tesla Supercharger network, with fifty charging stalls.

2.3K
10 Oct 2022

Topic Review

Respirator Cartridge

A respirator cartridge or canister is a container that cleans pollution from air. People working in polluted atmospheres use respirators for health preservation. If the air in the workplace is polluted with noxious gases, but contains sufficient oxygen (>19.5% in US; >18% in RF) they often use air-purifying respirators (APR). These respirators provide users breathable air by removing pollution from ambient air using canisters or cartridges. There are cartridges of different types, and they must be chosen correctly and replaced in a timely manner.

2.3K
11 Oct 2022

Topic Review

Saline (also known as saline solution) is a mixture of sodium chloride (salt) and water. It has a number of uses in medicine including cleaning wounds, removal and storage of contact lenses, and help with dry eyes. By injection into a vein it is used to treat dehydration such as that from gastroenteritis and diabetic ketoacidosis. Large amounts may result in fluid overload, swelling, acidosis, and high blood sodium. In those with long-standing low blood sodium, excessive use may result in osmotic demyelination syndrome. Saline is in the crystalloid family of medications. It is most commonly used as a sterile 9 g of salt per litre (0.9%) solution, known as normal saline. Higher and lower concentrations may also occasionally be used. Saline is acidic, with a pH of 5.5 (due mainly to dissolved carbon dioxide). The medical use of saline began around 1831. It is on the World Health Organization's List of Essential Medicines. In 2019, sodium was the 226th most commonly prescribed medication in the United States, with more than 2 million prescriptions.

2.3K
13 Oct 2022

Topic Review

The Energiewende (pronounced [ʔenɛʁˈɡiːˌvɛndə] (listen); German for '"energy transition"') is the ongoing transition by Germany to a low carbon, environmentally sound, reliable, and affordable energy supply. :4 The new system intends to rely heavily on renewable energy (particularly wind, photovoltaics, and hydroelectricity), energy efficiency, and energy demand management. Most if not all existing coal-fired generation are intended to be retired. Legislative support for the Energiewende was passed in late 2010 and included greenhouse gas (GHG) reductions of 80–95% by 2050 (relative to 1990) and a renewable energy target of 60% by 2050. Germany has already made significant progress on its GHG emissions reduction target prior to the introduction of the program, achieving a 27% decrease between 1990 and 2014. However the country would need to maintain an average GHG emissions abatement rate of 3.5% per year to reach its Energiewende goal, equal to the maximum historical value thus far. A controversial part of the program was the phasing out Germany's fleet of nuclear reactors, to be complete by 2022 with the aim of reaching a 100% renewable energy system and reducing greenhouse gas emissions from the energy sector. While the nuclear plants shutdown was mostly completed, they however were largely replaced by fossil gas and coal and most of the 2020 goals of the program were failed. A study found that if Germany had postponed the nuclear phase out and phased out coal first it could have saved 1,100 lives and $12 billion in social costs per year. Another article claims that Germany could have already phased out fossil fuels if it had chosen to invest in nuclear instead of renewable energy.

2.3K
31 Oct 2022

Topic Review

Conservation (Ethic)

Conservation's goals include protecting species from extinction, maintaining and restoring habitats, enhancing ecosystem services and protecting biological diversity. A range of values underlie conservation, which can be guided by biocentrism, anthropocentrism, ecocentrism and sentientism. There has recently been a movement towards evidence-based conservation which calls for greater use of scientific evidence to improve the effectiveness of conservation efforts.

2.3K
27 Apr 2023

Topic Review

Portal Vein Embolization of Indications and Contraindications

Preoperative portal vein embolization (PVE) via the purposeful occlusion of select portal vein branches to promote contralateral hepatic lobar hypertrophy has become the accepted standard for liver regeneration. Advances in embolic materials, selection of treatment approaches, and PVE with hepatic venous deprivation or concurrent transcatheter arterial embolization/radioembolization are all active areas of research. The primary indication for pre-operative PVE is centered on the inability of the pre-embolization future liver remnant (FLR) to support whole liver function post-resection. Contraindications to PVE are severe portal hypertension, uncontrollable intrahepatic portal-to-hepatic vein shunts, tumor thrombus in the portal vein, and occlusion of the portal vein in the FLR.

2.3K
14 Feb 2023

Topic Review

Therizinosaurs (or segnosaurs) were theropod dinosaurs belonging to the clade Therizinosauria. Therizinosaur fossils have been found in Early through Late Cretaceous deposits in Mongolia, the China and western North America. Various features of the forelimbs, skull and pelvis unite these finds as both theropods and as maniraptorans, close relatives to birds. The name therizinosaur is derived from the Greek θερίζω therízein, meaning 'to reap' or 'to cut off', and σαῦρος saûros meaning 'lizard'. The older name segnosaur is derived from Latin segnis meaning 'slow' or 'sluggish', and Greek σαυρος, sauros, meaning 'lizard'.

2.3K
16 Nov 2022

Topic Review

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

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

Calcium Phosphate Nanoparticles in Bone

Bone injuries and diseases constitute a burden both socially and economically, as the consequences of a lack of effective treatments affect both the patients’ quality of life and the costs on the health systems. This impended need has led to a recent focus on the development of efficacious bone tissue engineering solutions. Here, the use of biomaterial-based nanoparticles for the delivery of therapeutic factors is summrised. Among the biomaterials being considered to date, calcium phosphates have emerged as one of the most promising materials for bone repair applications due to their osteoconductivity, osteoinductivity and their ability to be resorbed in the body. Calcium phosphate nanoparticles have received particular attention as non-viral vectors for gene therapy, as factors such as plasmid DNAs, microRNAs (miRNA) and silencing RNA (siRNAs) can be easily incorporated on their surface. Calcium phosphate nanoparticles loaded with therapeutic factors have also been delivered to the site of bone injury using scaffolds and hydrogels. Here an overview of the use of calcium phosphate nanoparticles as carriers for therapeutic factors for application in bone tissue engineering is provided.

2.3K
30 Oct 2020

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