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Topic Review
CubeSat Missions and Their Antenna Designs
CubeSats are a class of miniaturized satellites that have become increasingly popular in academia and among hobbyists due to their short development time and low fabrication cost. Their compact size, lightweight characteristics, and ability to form a swarm enables them to communicate directly with one another to inspire new ideas on space exploration, space-based measurements, and implementation of the latest technology. CubeSat missions require specific antenna designs in order to achieve optimal performance and ensure mission success. Over the past, a plethora of antenna designs have been proposed and implemented on CubeSat missions. Several challenges arise when designing CubeSat antennas such as gain, polarization, frequency selection, pointing accuracy, coverage, and deployment mechanisms.
  • 5.7K
  • 18 Jul 2022
Topic Review
Ras Al Khaimah
Ras Al Khaimah (Arabic: رأس الخيمة; IPA: [raʔs alˈxajma]), historically known as Julfar, is one of the seven emirates that make up the United Arab Emirates (UAE). The capital city and home of most residents is also called Ras Al Khaimah, sometimes abbreviated as RAK city. Its name could be taken to mean "headland of the small huts", which can be attributed to the indigenous buildings that existed along the coast. The emirate is in the northern part of the UAE, bordering Oman's exclave of Musandam. It covers an area of 2,486 km2 (960 sq mi). The emirate had a population of 210,063 at the 2005 Census, of which 41.82 percent or 87,848 were Emirati citizens. Latest estimates put the total population at between 250,000 and 300,000. Locals accounted for 97,529 in the population estimate for 2010. Its capital city RAK city has two main sections, Old Ras Al Khaimah and Nakheel, on either side of a creek. It is served by the Ras Al Khaimah International Airport. It consists of a northern part (where the city of Ras al-Khaimah is situated), and a large inland exclave in the south (near Hatta), and a few small islands in the Persian Gulf. Ras Al Khaimah has the most fertile soil in the country, due to a larger share in rainfall and underground water streams from Omani mountains.
  • 5.7K
  • 19 Oct 2022
Topic Review
Leadership
Leadership is both a research area and a practical skill encompassing the ability of an individual or organization to "lead" or guide other individuals, teams, or entire organizations. Specialist literature debates various viewpoints, contrasting Eastern and Western approaches to leadership, and also (within the West) United States versus European approaches. U.S. academic environments define leadership as "a process of social influence in which a person can enlist the aid and support of others in the accomplishment of a common task". Leadership seen from a European and non-academic perspective encompasses a view of a leader who can be moved not only by communitarian goals but also, as the European researcher Daniele Trevisani sugggests, by the search for personal power. Studies of leadership have produced theories involving traits, situational interaction, function, behavior, power, vision and values, charisma, and intelligence, among others.
  • 5.7K
  • 21 Nov 2022
Topic Review
Phosphate in Primary Hyperparathyroidism
Serum phosphate is crucial in the management of kidney disease, playing a major role in vascular calcification in chronic kidney failure.  In the past 20 years, the role of phosphate has been profoundly reconsidered since many other molecules have been found to play important roles in phosphate homeostasis, beyond the well-known effect of parathyroid hormone (PTH) or renal function. The advent of new insights into phosphate metabolism must urge the endocrinologist to rethink the pathophysiology of widespread disorders, such as primary hyperparathyroidism.
  • 5.7K
  • 15 Dec 2021
Topic Review
Wave Energy Marine Buoys
The power supply is usually the bottleneck for marine distributed systems such as buoys. Wave energy technologies are especially useful in this sense, as they can capture and convert the promising “native” renewable energy in the ocean (i.e., wave energy) into electricity.
  • 5.7K
  • 08 Jul 2022
Topic Review
Neutrophils in Pregnancy, Term and Preterm Labour
Neutrophils are surveillance cells, and the first to react and migrate to sites of inflammation and infection following a chemotactic gradient. Neutrophils play a key role in both sterile inflammation and infection, performing a wide variety of effector functions such as degranulation, phagocytosis, ROS production and release of neutrophil extracellular traps (NETs). Healthy term labour requires a sterile pro-inflammatory process, whereas one of the most common causes of spontaneous preterm birth is microbial driven. Peripheral neutrophilia has long been described during pregnancy, and evidence exists demonstrating neutrophils infiltrating the cervix, uterus and foetal membranes during both term and preterm deliveries. Their presence supports a role in tissue remodelling via their effector functions.
  • 5.7K
  • 30 Oct 2022
Topic Review
Curcumin and Peripheral Neuropathies
Peripheral neuropathies (PN) can be triggered after metabolic diseases, traumatic peripheral nerve injury, genetic mutations, toxic substances, and/or inflammation. PN is a major clinical problem, affecting many patients and with few effective therapeutics. Recently, interest in natural dietary compounds, such as polyphenols, in human health has led to a great deal of research, especially in PN. Curcumin is a polyphenol extracted from the root of Curcuma longa. This molecule has long been used in Asian medicine for its anti-inflammatory, antibacterial, and antioxidant properties. However, like numerous polyphenols, curcumin has a very low bioavailability and a very fast metabolism. This part provides an overview of curcumin in the treatment of PN (anti-inflammatory, antioxidant, anti-endoplasmic reticulum stress (anti-ER-stress), neuroprotection, and glial protection). Finally, because PN are associated with numerous pathologies (e.g., cancers, diabetes, addiction, inflammatory disease...), this part is likely to interest a large audience.
  • 5.7K
  • 20 Oct 2020
Topic Review
Voyeurism
Voyeurism is the sexual interest in or practice of watching other people engaged in intimate behaviors, such as undressing, sexual activity, or other actions usually considered to be of a private nature. The term comes from the French voir which means "to see". A male voyeur is commonly labelled as "Peeping Tom" or a "Jags", a term which originates from the Lady Godiva legend. However, that term is usually applied to a male who observes somebody secretly and, generally, not in a public space. The American Psychiatric Association has classified certain voyeuristic fantasies, urges and behaviour patterns as a paraphilia in the Diagnostic and Statistical Manual (DSM-IV) if the person has acted on these urges, or the sexual urges or fantasies cause marked distress or interpersonal difficulty. It is described as a disorder of sexual preference in the ICD-10. The DSM-IV defines voyeurism as the act of looking at "unsuspecting individuals, usually strangers, who are naked, in the process of disrobing, or engaging in sexual activity". The diagnosis would not be given to people who experience typical sexual arousal simply by seeing nudity or sexual activity. In order to be diagnosed with voyeuristic disorder the symptoms must persist for over six months and the person in question must be over the age of 18.
  • 5.7K
  • 11 Nov 2022
Topic Review
Niobium Oxides
Niobium oxides (NbO, NbO2, Nb2O5), being a versatile material has achieved tremendous popularity to be used in a number of applications because of its outstanding electrical, mechanical, chemical, and magnetic properties. NbxOy films possess a direct band gap within the ranges of 3.2–4.0 eV, with these films having utility in different applications which include; optical systems, stainless steel, ceramics, solar cells, electrochromic devices, capacitor dielectrics, catalysts, sensors, and architectural requirements. With the purpose of fulfilling the requirements of a vast variety of the named applications, thin films having comprehensive properties span described by film composition, morphology, structural properties, and thickness are needed.
  • 5.7K
  • 06 Jan 2021
Topic Review
Procedures for Extraction of Anthocyanins from Different Food
Anthocyanins are water-soluble pigments characterized by various intense colors found in fruits and vegetables. The extraction and separation of anthocyanins from plants is important, especially due to the instability of plant anthocyanins, selecting and optimizing. Anthocyanins are prone to degradation by several factors, including pH, temperature, oxygen, water activity, co-pigments and enzymes. Unwanted compounds, such as sugars, proteins, lipids, acids and other flavonoids, can also be removed from plant material by appropriate extraction methods. The most used method for anthocyanin extraction is the conventional one, solid–liquid extraction, also known as solvent extraction, during which anthocyanins can be dissolved in polar solvents (methanol/glycolic acid and acetone), followed by their quantification, achieved by using spectrophotometry, the differential pH method, which is a rapid and convenient quantitative assay. Starting from this point, it has developed and there are many anthocyanin-extraction methods, such as conventional solvent extraction (CSE), enzyme-assisted extraction (EAE), fermentation extraction (FE), supercritical fluid extraction (SFE) (CO2) extraction, microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), high-hydrostatic-pressure extraction (HHPE) and pressurized-liquid extraction (PLE). One of the most frequent techniques for obtaining anthocyanins from plants is conventional solvent extraction. In order to meet the demands of safety and environmental sustainability, new extraction technologies with shorter extraction periods and higher yields have been developed (e.g., PLE, EFS, UAE, MAE, EAE, etc.).
  • 5.7K
  • 29 Nov 2022
Topic Review
Vulnerability of Buildings
Vulnerability is defined for buildings as the degree of loss resulting from a hazard at a certain severity level and depends on the reduction in resistance and the level of decay in the structures as a result of constant exposure to environmental factors (such as seismic actions). 
  • 5.7K
  • 23 Nov 2021
Topic Review
Biostimulants
Biostimulants represent a promising type of environment-friendly formulation based on natural products that are frequently used exogenously to enhance abiotic stress tolerance. There is no specific definition of biostimulants yet, despite their regulatory functions in plant growth and development. Biostimulants originate from natural sources and can be effectively categorized into the following four prime groups, namely, acids, microbes, plant-derived bioactive substances, and others.
  • 5.7K
  • 08 Apr 2022
Topic Review
Abiotic and Biotic Polymer Degradation Mechanisms
Polymer degradation is defined as an irreversible change of the chemical structure, physical properties, and visual appearance due to the chemical cleavage of the polymer’s constitutive macromolecules by one or more mechanism. More than one mechanism can simultaneously take place due to the action of external factors, and one mechanism can be more dominant than others at any time. External factors associated with the environment, such as heat, humidity, radiation, and acidic or alkaline conditions, could modify the degradation process and its rate. The degradation process can alter polymer properties such as mechanical, optical, electrical, discoloration, phase separation or delamination, erosion, cracking, and crazing. The four main abiotic mechanisms associated with polymer degradation are mechanical, thermal (or thermo-oxidative), photo (photo-oxidative), and hydrolytic (chemical) degradation, some of which can be assisted by catalysis. In addition, ozone degradation (chemical) is considered a mechanism of degradation for polymers but is less common. The biotic degradation involves the action of microorganisms by enzymatic action.
  • 5.7K
  • 27 Oct 2022
Topic Review
Effector-Triggered Immunity in Plants
Plants rely on multiple immune systems to protect themselves from pathogens. When pattern-triggered immunity (PTI)—the first layer of the immune response—is no longer effective as a result of pathogenic effectors, effector-triggered immunity (ETI) often provides resistance. In ETI, host plants directly or indirectly perceive pathogen effectors via resistance proteins and launch a more robust and rapid defense response. Resistance proteins are typically found in the form of nucleotide-binding and leucine-rich-repeat-containing receptors (NLRs). Upon effector recognition, an NLR undergoes structural change and associates with other NLRs. The dimerization or oligomerization of NLRs signals to downstream components, activates “helper” NLRs, and culminates in the ETI response. Originally, PTI was thought to contribute little to ETI. However, most recent studies revealed crosstalk and cooperation between ETI and PTI.
  • 5.7K
  • 31 May 2021
Topic Review
Biological Properties of Flavonoids
It has been reported that nutritional phytochemicals present in fruits, vegetables and cereals, such as flavonoid polyphenolic compounds, can improve bone mineral density by several mechanisms, in addition to having beneficial effects on bone homeostasis and health. In addition to their nutritional properties, flavonoids may have applicability in the manufacture of polymers and can be used as stabilizing agents for biopolyesters, such as polylactide (PLA) and polyhydroxyalkanoate (PHA), which have been widely used in tissue engineering for membranes and scaffolds.
  • 5.7K
  • 11 May 2022
Topic Review
Kuroshio Current
The Kuroshio (黒潮), also known as the Black or Japan Current (日本海流, Nihon Kairyū) or the Black Stream, is a north-flowing, warm ocean current on the west side of the North Pacific Ocean. Like the Gulf Stream in the North Atlantic, the Kuroshio is a powerful western boundary current and forms the western limb of the North Pacific Subtropical Gyre.
  • 5.6K
  • 09 Oct 2022
Topic Review
Alchemy and Chemistry in Medieval Islam
Alchemy and chemistry in Islam refers to the study of both traditional alchemy and early practical chemistry (the early chemical investigation of nature in general) by scholars in the medieval Islamic world. The word alchemy was derived from the Arabic word كيمياء or kīmiyāʾ. and may ultimately derive from the ancient Egyptian word kemi, meaning black. After the fall of the Western Roman Empire, the focus of alchemical development moved to the Caliphate and the Islamic civilization. Much more is known about Islamic alchemy as it was better documented; most of the earlier writings that have come down through the years were preserved as Arabic translations.
  • 5.6K
  • 24 Nov 2022
Topic Review
Talkboy
Talkboy is a line of handheld voice recorder and sound novelty toys manufactured by Tiger Electronics (now owned by Hasbro) in the 1990s. The Talkboy was originally conceived as a cassette recorder and player prop for the 1992 film Home Alone 2: Lost in New York. At the request of director John Hughes and 20th Century Fox, Tiger designed and built the prop, and was given permission by the movie studio to sell a retail version of the toy. Two cassette recorders modeled after the film prop were released in 1992 and 1993, respectively. The original model did not have the variable-speed voice changer of the film version and sold only moderately during the 1992 holiday shopping season. In April 1993, Tiger released the Deluxe model, which added the voice-changing feature. Following the release of Home Alone 2 on home video in July with an insert advertising the Deluxe Talkboy, interest in the toy spiked. Retailers had severely underestimated demand, and as a result the Deluxe Talkboy was one of the most highly sought-after toys during the 1993 holiday shopping season, selling out of stores across the United States. A pink version of the cassette recorder called "Deluxe Talkgirl" was released in 1995. The success of the Talkboy cassette recorders spawned a product line of electronic toys. Tiger transitioned to digital recorders for subsequent devices, using solid-state storage and adding sound effects, beginning with "Talkboy/Talkgirl F/X+" pens in 1995, which sold more than a million units in 45 days.
  • 5.6K
  • 29 Nov 2022
Topic Review
Folic Acid, Vitamin B12 and Chronic Kidney Disease
Patients affected by chronic kidney disease (CKD) or end-stage renal disease (ESRD) experience a huge cardiovascular risk and cardiovascular events represent the leading causes of death. Folic acid and vitamin B12 could not only be mere cofactors in the homocysteine metabolism; they may have a direct action in determining tissue damage and cardiovascular risk. 
  • 5.6K
  • 15 Oct 2021
Topic Review
Theory of Addiction
Drug addiction is characterized by a loss of control over drug-seeking and -consumption, despite the profound negative consequences this has on the individual’s life [1]. While the acute effects of a substance depend on its psychoactive properties, the progression of addiction converges into a series of problems that are common and severely impact all spheres of the individual’s life, compromising interpersonal, economic, and health status. Thus, in chronic drug users it is common to present several physical problems including brain damage and atrophy, circulatory system issues, premature aging, among others. From a socio-economic perspective, common problems include homelessness, criminal behavior, unemployment, social isolation, and dependence.
  • 5.6K
  • 01 Feb 2024
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