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Topic Review
DPPH Radical Scavenging Assay
The 1,1-diphenyl-2-picrylhydrazil (DPPH) radical removal is one of the most widely applied and used methods in food and pharmaceutical applications. DPPH method gives a better response for mostly phenolic compounds and then for compounds with limited polarity. In the case of polar and phenolic compounds, adding water to the reaction medium, that is, aqueous methanol, gives better results. When testing low-polarity compounds, ethyl acetate with a radical is suitable. DPPH reaction rates depend on the steric accessibility of the radical site rather than the chemical properties of the tested antioxidant compounds. The rate at which DPPH reacts with antioxidants depends on the varying ratios of mixed single-electron transfer (SET) and hydrogen atom transfer (HAT) mechanisms. The reaction mechanisms of DPPH∙ scavenging and responses are modified by many environmental and experimental factors.
  • 17.6K
  • 08 Sep 2023
Topic Review
Insights into Si-Si and Si-H Bond
During the last decades, the search for new methodologies for the synthesis of organosilicon compounds have increased due to the multiple applications in industry, in academy, among other areas. Silicon-hydrogen and silicon-silicon bond activation by d-block metals still represent the most important pathways for obtaining molecular entities that contain, witihin their structures, silane motifs. Although the chemistry of Si-H bond activation is under continue development, Si-Si bonds are poorly characterized and less used and thus, disilanes represent good starting precursors because of their stability towards ambient conditions. The present entry will focus on the physicochemical properties of Si-H and Si-Si bonds, some trends and finally highlighting their impact on the synthesis of metal complexes.
  • 17.5K
  • 15 Feb 2023
Topic Review
In-Vehicle Networks
Modern vehicles are no longer simply mechanical devices. Connectivity between the vehicular network and the outside world has widened the security holes that hackers can use to exploit a vehicular network. Controller Area Network (CAN), FlexRay, and automotive Ethernet are popular protocols for in-vehicle networks (IVNs) and will stay in the industry for many more years. However, these protocols were not designed with security in mind. They have several vulnerabilities, such as lack of message authentication, lack of message encryption, and an ID-based arbitration mechanism for contention resolution. Adversaries can use these vulnerabilities to launch sophisticated attacks that may lead to loss of life and damage to property. Thus, the security of the vehicles should be handled carefully. In this paper, we investigate the security vulnerabilities with in-vehicle network protocols such as CAN, automotive Ethernet, and FlexRay. A comprehensive survey on security attacks launched against in-vehicle networks is presented along with countermeasures adopted by various researchers. Various algorithms have been proposed in the past for intrusion detection in IVNs. However, those approaches have several limitations that need special attention from the research community. Blockchain is a good approach to solving the existing security issues in IVNs, and we suggest a way to improve IVN security based on a hybrid blockchain.
  • 17.4K
  • 15 Apr 2021
Topic Review
Manimekalai
Manimekalai (Tamil: மணிமேகலை), by the poet Chithalai Chathanar, is one of The Five Great Epics of Tamil Literature according to later Tamil literary tradition. Manimekalai is a poem in 30 cantos. Its story is a sequel to another of the Five Great Epics, Silappatikaram, and tells the story of the daughter of Kovalan and Madhavi, who became a Buddhist Bikkuni.
  • 17.4K
  • 24 Oct 2022
Topic Review
Ballistic Missile
A ballistic missile follows a ballistic trajectory to deliver one or more warheads on a predetermined target. These weapons are only guided during relatively brief periods of flight—most of their trajectory is unpowered, being governed by gravity and air resistance if in the atmosphere. Shorter range ballistic missiles stay within the Earth's atmosphere, while longer-ranged intercontinental ballistic missiles (ICBMs), are launched on a sub-orbital flight trajectory and spend most of their flight out of the atmosphere. These weapons are in a distinct category from cruise missiles, which are aerodynamically guided in powered flight.
  • 17.4K
  • 05 Nov 2022
Topic Review
Higher Education and COVID-19
The COVID-19 pandemic had profound consequences on the educational dimension, with the temporary closure of educational institutions, as well as the impediment of face-to-face classes. These challenging conditions can be a critical moment of opportunity to reshape education in higher education, with the implementation, development, and diffusion of digital technologies.
  • 17.4K
  • 20 Oct 2020
Topic Review
Philippine Hokkien
Philippine Hokkien (Chinese: 咱儂話; Pe̍h-ōe-jī: Lán-lâng-ōe; literally: 'our people's language'), is the variant of Hokkien as spoken by about 98.7% of the ethnic Chinese population of the Philippines. A mixed version that involves this language with Tagalog and English is Hokaglish.
  • 17.3K
  • 06 Oct 2022
Topic Review
Davidic Line
The Davidic line or House of David (Hebrew: בית דוד‎, romanized: Beit David) refers to the lineage of the Israelite king David through texts in the Hebrew Bible, the New Testament, and through the succeeding centuries. According to the Bible, David, of the Tribe of Judah, was the third king of the United Monarchy of Israel and Judah. He was later succeeded by his son, Solomon. After Solomon's death, the ten northern tribes rejected the Davidic line, refusing to accept Solomon's son, Rehoboam, and instead chose as king Jeroboam and formed the northern Kingdom of Israel. The southern tribes of Judah and Benjamin remained loyal to the House of David, and this kingdom came to be known as the Kingdom of Judah. All subsequent kings of Judah, except Athaliah, are said to be direct descendants of David. The kingdom fell to the Neo-Babylonian Empire in 587/6 BCE. The Hasmoneans, who established their own monarchy in Judea in the 2nd century BCE, were not considered connected to the Davidic line nor to the Tribe of Judah. In Judaism and Christianity, the Davidic Line is the bloodline from which the Hebrew Messiah has a patrilineal descent. In Jewish eschatology, the Messiah is a future Jewish king from the Davidic line, who is expected to rule the Jewish people during the Messianic Age and world to come. The Christian gospels claim that Jesus descends from the Davidic line and is therefore the legitimate Hebrew Messiah. The New Testament books of Matthew and Luke give two different accounts of the genealogy of Jesus that trace back to David.
  • 17.3K
  • 02 Dec 2022
Topic Review
6061 Aluminium Alloy
6061 (Unified Numbering System (UNS) designation A96061) is a precipitation-hardened aluminium alloy, containing magnesium and silicon as its major alloying elements. Originally called "Alloy 61S", it was developed in 1935. It has good mechanical properties, exhibits good weldability, and is very commonly extruded (second in popularity only to 6063). It is one of the most common alloys of aluminum for general-purpose use. It is commonly available in pre-tempered grades such as 6061-O (annealed), tempered grades such as 6061-T6 (solutionized and artificially aged) and 6061-T651 (solutionized, stress-relieved stretched and artificially aged).
  • 17.2K
  • 22 Nov 2022
Topic Review
Pharmacological Applications of Piperidine Derivatives
Piperidine is a six-membered heterocycle including one nitrogen atom and five carbon atoms in the sp3-hybridized state. Piperidine-containing compounds represent one of the most important synthetic medicinal blocks for drugs construction, and their synthesis has long been widespread. It can be unequivocally stated that heterocyclic compounds play a significant part in the pharmaceutical industry, and one of the most common in their structure is the piperidine cycle. 
  • 17.2K
  • 09 Feb 2023
Topic Review
Water Quality Degradation
Water quality degradation is happened through the natural processes that influence the surface water and groundwater quality by various sources such as climate changes, natural disasters, geological factors, soil-matrix, and hyporheic exchange. Water could also be contaminated by anthropogenic factors. Anthropogenic pollutants are substances caused by human actions, mostly resulting from land-use practices. 
  • 17.2K
  • 05 Feb 2022
Topic Review
Magnoliophyta
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (/ˌændʒiəˈspɜːrmiː/), commonly called angiosperms. The term "angiosperm" is derived from the Greek words angeion ('container, vessel') and sperma ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (/mæɡˌnoʊliˈɒfətə, -əˈfaɪtə/). Like gymnosperms, angiosperms are seed-producing plants. They are distinguished from gymnosperms by characteristics including flowers, endosperm within their seeds, and the production of fruits that contain the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. The closest fossil relatives of flowering plants are uncertain and contentious. The earliest angiosperm fossils are in the form of pollen around 134 million years ago during the Early Cretaceous. Over the course of the Cretaceous, angiosperms explosively diversified, becoming the dominant group of plants across the planet by the end of the period, corresponding with the decline and extinction of previously widespread gymnosperm groups. The origin and diversification of the angiosperms is often known as "Darwin's abominable mystery".
  • 17.2K
  • 28 Nov 2022
Topic Review
Hydrogen Storage and Transportation
In the current hydrocarbon economy, transportation is fueled primarily by petroleum. Burning of hydrocarbon fuels emits carbon dioxide and other pollutants. The supply of economically usable hydrocarbon resources in the world is limited, and the demand of hydrocarbon fuels is increasing, particularly in China, India and other countries. Proponents of a world-scale hydrogen economy argue that hydrogen can be environmentally cleaner source of energy to end-users, particularly in transportation applications, without release of pollutants (such as particulate matter) or carbon dioxide at the point of end use. A recent analysis asserted that “most of the hydrogen supply chain pathways would release significantly less carbon dioxide into the atmosphere than would gasoline used in hybrid electric vehicles” and that significant reductions in carbon dioxide emissions would be possible if carbon capture or carbon sequestration methods were utilized at the site od energy or hydrogen production. Hydrogen storage can be distributed continuously in pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system also pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels. Furthermore, hydrogen is regenerative and environment friendly. But two difficulties with hydrogen are that hydrogen is just an energy carrier and has a low critical temperature of 35 K, i.e., hydrogen is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific surface area (at T< 100K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent and ionic compounds (at ambient pressure), oxidation of reactive metals e.g., Li, Na, Mg, Al, Zn with water. These metals easily react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can be thermally reduced to the metals in a solar furnace. In conclusion, routes for the transmission and storage of hydrogen for chemical processes, and hydrogen-based energy systems are increasing their establishment. Here, these routes are described, considering their attractions and difficulties.
  • 17.2K
  • 18 Jun 2021
Topic Review
Adolescents Malnutrition
Adolescents are young individuals that are between the ages of 10 and 19 years old.  Malnutrition refers to deficiencies, excesses or imbalances in an individual intake of energy and/or nutrients 
  • 17.1K
  • 16 Jul 2021
Topic Review
Solar Power Plants in Iran
The world’s electricity generation has increased with renewable energy technologies such as solar (solar power plant), wind energy (wind turbines), heat energy, and even ocean waves. Iran is in the best condition to receive solar radiation due to its proximity to the equator (25.2969° N). In 2020, Iran was able to supply only 900 MW (about 480 solar power plants and 420 MW home solar power plants) of its electricity demand from solar energy, which is very low compared to the global average. Yazd, Fars, and Kerman provinces are in the top ranks of Iran, with the production of approximately 68, 58, and 47 MW using solar energy, respectively. Iran also has a large area of vacant land for the construction of solar power plants.
  • 17.1K
  • 07 Jan 2022
Topic Review
Smart Clothing
Smart clothing can be defined as the intelligent system that senses and reacts to the changes and stimuli of the environment and the wearer’s conditions, such as electrical, thermal and magnetic ones. Smart clothing has various functions (e.g., protection, temperature regulation, monitoring, entertainment, expression of personality, etc.) and embodies many features (e.g., efficient, intelligent, computable, etc.), combining cutting-edge technologies in related fields such as electronic information, sensors and materials. Smart clothing has emerged to meet consumers’ personalized needs in healthcare, work, entertainment, etc., and has rapidly become a hotspot in the clothing industry and research field. However, as smart clothing gets popular, sustainability issues are becoming increasingly prominent during its development and circulation. 
  • 17.1K
  • 19 Apr 2022
Topic Review
Classification of Green Solvents
Green solvents, such as bio-based (derived from renewable sources), water-based (dissolved in water), supercritical fluids (above their critical point), and deep eutectic solvents (formed by mixing two or more components), offer alternatives to conventional organic solvents for bio-oil extraction. These solvents are characterized by being non-toxic, non-volatile, recyclable, and biodegradable.
  • 17.1K
  • 16 Aug 2023
Topic Review
Ali in the Quran
The majority of Islamic commentators do not believe that Ali ibn Abu Talib (Arabic: عَـلِي ابْـن أَبُـو طَـالِـب) is mentioned explicitly in the Quran. However, Shi'ite scholars and some Sunni scholars interpret many Quranic verses as referring to Ali. Shi'ite scholars also believe other Imams have been referred in the Quran. They believe Imams are referred to as "the signs of Allah, the way, the straight path, the light of Allah, the inheritors of the Book, the people of knowledge, the holders of authority and other such designations," Shi'ite sources state, Muhammad al-Baqir answers: "Allah revealed Salat to his Prophet but never said of three or four Rakats, revealed Zakat but did not mention to its details, revealed Hajj but did not count its Tawaf and the Prophet interpreted their details. Allah revealed this verse and Prophet said this verse is about Ali, Hasan, Husayn and the other Twelve Imams." Shi'ite scholars, thus, have argued that a quarter of Qur'anic verses are stating the station of imams. Such a view is rejected by Sunni scholars, who argue that some of these verses instead refer to the Quraysh or Muhammad's wives.
  • 17.1K
  • 14 Oct 2022
Topic Review
Understanding Sexual Agency
Debates on human agency, not least female and sexual agency, have permeated the social scientific literature and health educational practice during multiple decades now. This article provides a review of recent agency debates, illustrating how criticisms of traditional conceptions of (sexual) agency have led to a notable diversification of the concept. We propose a comprehensive, inclusive description of sexual agency, focusing on the navigation of goals and desires in the wider structural context, and acknowledging the many forms sexual agency may take. We argue there is no simple relation between sexual agency and sexual health. We propose the following description: Sexual agency refers to a continuum of dynamic, everyday, situated modalities of action related to sexuality in which agents navigate (contrarieties between) personal goals, desires and preferences on the one, and personal living conditions, normative expectations and the wider structural context on the other hand. A diversity of internal (e.g. self-identification) and/or external goals (e.g. maintain social relationships or challenge the status quo) motivate and direct sexually agentic behavior. Sexual agency may aim for change as well as for endurance, continuity and stability. It may be overt or tacit. It varies with individual (e.g. temporal orientation) as well as situational variables (e.g. novelty). Sexual agency may reproduce but also resist and renegotiate (aspects of) prevailing norms and the status quo. There is no simple relation between sexual agency and sexual health or well-being. Modalities of action as well as the constructiveness of their (multiple) effects always depend on personal frames of reference as well as on the opportunities and restrictions provided by the (immediate and distant) personal and structural context, including moral and ideological frameworks and dominant sexual stories.
  • 17.1K
  • 21 Oct 2021
Topic Review
Injection
An injection (often and usually referred to as a "shot" in US English, a "jab" in UK English, or a "jag" in Scottish English and Scots) is the act of administering a liquid, especially a drug, into a person's body using a needle (usually a hypodermic needle) and a syringe. An injection is considered a form of parenteral drug administration; it does not involve absorption in the digestive tract. This allows the medication to be absorbed more rapidly and avoid the first pass effect. There are many types of injection, which are generally named after the body tissue the injection is administered into. This includes common injections such as subcutaneous, intramuscular, and intravenous injections, as well as less common injections such as intraperitoneal, intraosseous, intracardiac, intraarticular, and intracavernous injections. Injections are among the most common health care procedures, with at least 16 billion administered in developing and transitional countries each year. Of these, 95% are used in curative care or as treatment for a condition, 3% are to provide immunizations/vaccinations, and the rest are used for other purposes, including blood transfusions. The term injection is sometimes used synonymously with inoculation, but injection does not only refer to the act of inoculation. Injections generally administer a medication as a bolus (or one-time) dose, but can also be used for continuous drug administration. After injection, a medication may be designed to be released slowly, called a depot injection, which can produce long-lasting effects. An injection necessarily causes a small puncture wound to the body, and thus may cause localized pain or infection. The occurrence of these side effects varies based on injection location, the substance injected, needle gauge, procedure, and individual sensitivity. Rarely, more serious side effects including gangrene, sepsis, and nerve damage may occur. Fear of needles, also called needle phobia, is also common and may result in anxiety and fainting before, during, or after an injection. To prevent the localized pain that occurs with injections the injection site may be numbed or cooled before injection and the person receiving the injection may be distracted by a conversation or similar means. To reduce the risk of infection from injections, proper aseptic technique should be followed to clean the injection site before administration. If needles or syringes are reused between people, or if an accidental needlestick occurs, there is a risk of transmission of bloodborne diseases such as HIV and hepatitis. Unsafe injection practices contribute to the spread of bloodborne diseases, especially in less-developed countries. To combat this, safety syringes exist which contain features to prevent accidental needlestick injury and reuse of the syringe after it is used once. Furthermore, recreational drug users who use injections to administer the drugs commonly share or reuse needles after an injection. This has led to the development of needle exchange programs and safe injection sites as a public health measure, which may provide new, sterile syringes and needles to discourage the reuse of syringes and needles. Used needles should ideally be placed in a purpose-made sharps container which is safe and resistant to puncture. Some locations provide free disposal programs for such containers for their citizens.
  • 17.0K
  • 04 Nov 2022
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