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Topic Review
IgG Transplacental Transfer: Benefits & Risks
IgG antibodies can cross and do cross the placenta during pregnancy from the mother to the fetus. The passage starts by the end of the first trimester and continues throughout pregnancy. This is a manner by which the fetus gets passive humoral immunity from the mother. In the early neonatal period, these transferred maternal antibodies will act as a defense and help the developing immunity of the baby. While they are short-lived and cleared from the neonatal circulation within several months, they may be very helpful. A down-side is that in certain maternal autoimmune conditions auto-antibodies seem to have the capacity to hijack the transfer mechanism. It is the case for anti-Ro antibodies. These antibodies are frequent in women with systemic lupus erythematosus and/or Sjogren syndrome. They can lead to fetal atrioventricular block.   
  • 5.7K
  • 17 Jan 2022
Topic Review
Food Security
Food security is a measure of the availability of food and individuals' ability to access it. Affordability is only one factor. There is evidence of food security being a concern many thousands of years ago, with central authorities in ancient China and ancient Egypt being known to release food from storage in times of famine. At the 1974 World Food Conference the term "food security" was defined with an emphasis on supply. They said food security is the "availability at all times of adequate, nourishing, diverse, balanced and moderate world food supplies of basic foodstuffs to sustain a steady expansion of food consumption and to offset fluctuations in production and prices". Later definitions added demand and access issues to the definition. The final report of the 1996 World Food Summit states that food security "exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life." Household food security exists when all members, at all times, have access to enough food for an active, healthy life. Individuals who are food secure do not live in hunger or fear of starvation. Food insecurity, on the other hand, is defined by the United States Department of Agriculture (USDA) as a situation of "limited or uncertain availability of nutritionally adequate and safe foods or limited or uncertain ability to acquire acceptable foods in socially acceptable ways". Food security incorporates a measure of resilience to future disruption or unavailability of critical food supply due to various risk factors including droughts, shipping disruptions, fuel shortages, economic instability, and wars. In the years 2011–2013, an estimated 842 million people were suffering from chronic hunger. The Food and Agriculture Organization of the United Nations, or FAO, identified the four pillars of food security as availability, access, utilization, and stability. The United Nations (UN) recognized the Right to Food in the Declaration of Human Rights in 1948, and has since said that it is vital for the enjoyment of all other rights. The 1996 World Summit on Food Security declared that "food should not be used as an instrument for political and economic pressure".
  • 5.7K
  • 16 Nov 2022
Topic Review
Peppercorn (Legal)
In legal parlance, a peppercorn is a metaphor for a very small cash payment or other nominal consideration, used to satisfy the requirements for the creation of a legal contract. It is featured in Chappell & Co Ltd v Nestle Co Ltd ( AC 87), which stated that "a peppercorn does not cease to be good consideration if it is established that the promisee does not like pepper and will throw away the corn". What is unusual about the term is that it came into the language when peppercorns were extremely expensive; coming, as they exclusively did, from the Dutch Moluccas. Yet today, the term is more-or-less synonymous with ”a pittance“ — something of minimal value.
  • 5.6K
  • 01 Nov 2022
Topic Review
Understanding Hotel Service Failures
Service failure is inevitable. Service in the hospitality industry involves multiple interactions between the service providers and customers, and a high risk of service failures accompanies these interactions. Although empirical studies on the outcomes and processes of service failures have been conducted in the hotel industry, the findings need more exploration to understand how different segments perceive service failures and the associated emotions differently. This study revealed the similarities and differences between groups (i.e., men vs. women and leisure vs. business) in reporting service failures. Different meanings of words that emerged from the text-mining results were also examined to ensure a more comprehensive understanding of the guest experience.
  • 5.6K
  • 15 Mar 2022
Topic Review
Unlawful Combatant
An unlawful combatant, illegal combatant or unprivileged combatant/belligerent is, according to United States law, a person who directly engages in armed conflict in violation of the laws of war and therefore is claimed to not be protected by the Geneva Conventions. The International Committee of the Red Cross points out that the terms "unlawful combatant", "illegal combatant" or "unprivileged combatant/belligerent" are not defined in any international agreements. The Geneva Conventions apply in wars between two or more sovereign states. Article 5 of the Third Geneva Convention states that the status of detainees whose combatant status is in doubt should be determined by a "competent tribunal". Until such time, they must be treated as prisoners of war. After a "competent tribunal" has determined that an individual is not a lawful combatant, the "detaining power" may choose to accord the individual the rights and privileges of a prisoner of war as described in the Third Geneva Convention, but is not required to do so. An individual who is not a lawful combatant, who is not a national of a neutral state, and who is not a national of a co-belligerent state, retains rights and privileges under the Fourth Geneva Convention so that he must be "treated with humanity and, in case of trial, shall not be deprived of the rights of fair and regular trial". While the concept of an unlawful combatant is included in the Third Geneva Convention, the phrase itself does not appear in the document. Article 4 of the Third Geneva Convention does describe categories under which a person may be entitled to POW status. There are other international treaties that deny lawful combatant status for mercenaries and children. In the United States, the Military Commissions Act of 2006 codified the legal definition of this term and invested the U.S. President with broad discretion to determine whether a person may be designated an unlawful enemy combatant under United States law. The assumption that unlawful combatant status exists as a separate category to lawful combatant and civilian is contradicted by the findings of the International Criminal Tribunal for the Former Yugoslavia in the Celebici Judgment. The judgment quoted the 1958 International Committee of the Red Cross (ICRC) commentary on the Fourth Geneva Convention: "Every person in enemy hands must be either a prisoner of war and, as such, be covered by the Third Convention; or a civilian covered by the Fourth Convention. There is no intermediate status; nobody in enemy hands can be outside the law". Thus, anyone not entitled to prisoner of war status maintains the same rights as a civilian, and must be prosecuted under domestic law. Neither status exists in non-international conflict, with all parties equally protected under International Humanitarian Law. The Geneva Conventions do not recognize any status of lawfulness for combatants in conflicts not involving two or more nation states, such as during civil wars between government's forces, and insurgents. A state in such a conflict is legally bound only to observe Common Article 3 of the Geneva Conventions and may ignore all of the other Articles. But each one of them is completely free to apply all or part of the remaining Articles of the Convention.
  • 5.6K
  • 02 Dec 2022
Topic Review
Neck (Water Spirit)
The neck, nicor, nokk, nix, nixie, nixy, or nokken (German: Nixe; Dutch: nikker, nekker; Danish: nøkke; Norwegian: nøkken; Swedish: näck; Faroese: nykur; Finnish: näkki; Estonian: näkk) are shapeshifting water spirits in Germanic mythology and folklore who usually appeared in the form of other creatures. Under a variety of names, they were common to the stories of all Germanic peoples, although they are perhaps best known from Scandinavian folklore. The related English knucker was generally depicted as a wyrm or dragon, although more recent versions depict the spirits in other forms. Their sex, bynames, and various transformations vary geographically. The German Nix and his Scandinavian counterparts were male. The German Nixe was a female river mermaid.
  • 5.6K
  • 18 Oct 2022
Topic Review
Annular Erythemas and Purpuras
Annular dermatoses (AD) are a heterogeneous group of skin diseases, whose common feature is essentially the annular or circular arrangement of the lesions with centrifugal spreading. They belong to the group of figurate dermatoses, to which can be added linear or serpiginous dermatoses, for example. They are a fascinating curiosity for the dermatologist, as they form patterns and arabesques on the patient’s body.
  • 5.6K
  • 01 Jun 2023
Topic Review
Compounds of Oxygen
The oxidation state of oxygen is −2 in almost all known compounds of oxygen. The oxidation state −1 is found in a few compounds such as peroxides. Compounds containing oxygen in other oxidation states are very uncommon: −​1⁄2 (superoxides), −​1⁄3 (ozonides), 0 (elemental, hypofluorous acid), +​1⁄2 (dioxygenyl), +1 (dioxygen difluoride), and +2 (oxygen difluoride). Oxygen is reactive and will form oxides with all other elements except the noble gases helium, neon, argon, and krypton.
  • 5.6K
  • 26 Oct 2022
Topic Review
Clinical Overview of Oral Cavity Cancer
Head and neck cancers are the 6th most common cancers in the United States and responsible for nearly 2% of all deaths related to cancer. Approximately 95% of all head and neck cancers are squamous cell carcinoma (SCC); of which, oral cavity SCC is the most common (excluding non-melanoma cutaneous cancers). The incidence of oral cavity cancer has gradually increased over the past 20 years. Globally, there were more than 375,000 new cases of oral cavity cancers (including cancers of the lip) and more than 175,000 deaths in 2020.
  • 5.6K
  • 10 Jan 2022
Topic Review
Geopolymer Concrete (GPC)
Geopolymer concrete (GPC) is a new material in the construction industry, with different chemical compositions and reactions involved in a binding material. The pozzolanic materials (industrial waste like fly ash, ground granulated blast furnace slag (GGBFS), and rice husk ash), which contain high silica and alumina, work as binding materials in the mix. The sustainable development can be achieved by employing geopolymers in construction industries, because it results in lower CO2 emissions, optimum utilization of natural resources, utilization of waste materials, low energy consumption, thermally stability, more cost-effective in long life infrastructure construction, and, socially, financial benefits and employment generation
  • 5.6K
  • 18 Apr 2022
Topic Review
Multilayer Ceramic Capacitors and Its Fabrication Process
The high performance, multi-functionality, and high integration of electronic devices are made possible in large part by the multilayer ceramic capacitors (MLCCs). Due to their low cost, compact size, wide capacitance range, low equivalent series inductance (ESL) and equivalent series resistance (ESR), and excellent frequency response, MLCCs play a significant role in contemporary electronic devices.
  • 5.6K
  • 20 Mar 2023
Topic Review
Aloe vera
Aloe vera plant offers a sustainable solution for the removal of various pollutants from water. Due to its chemical composition, Aloe vera has been explored as coagulant/flocculant and biosorbent for water treatment. 
  • 5.6K
  • 23 Jun 2021
Topic Review
Chromatographic Techniques in Pharmaceutical Analysis
High-performance liquid chromatography (HPLC) is an incredibly universal tool, especially when combined with different detectors, such as UV-Visible spectroscopy, mass spectrometry (MS), and fluorescence detection for numerous active ingredients in different pharmaceutical formulations without interferences from other excipients. TLC, in combination with densitometry, is a very efficient tool for the determination of biologically active substances present in pharmaceutical preparations. In addition, TLC coupled to densitometry and mass spectrometry could be suitable for preliminary screening and determination of the biological activity (e.g., antioxidant properties, thin layer chromatography (TLC) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method) of plant materials. Gas chromatography, coupled with a mass spectrometer (GC-MS, GC-MS/MS), is of particular importance in the testing of any volatile substances, such as essential oils. LC, coupled to NMR and MS, is the best solution for identifying and studying the structure of unknown components from plant extracts, as well as degradation products (DPs). Thanks to size-exclusion chromatography, coupled to multi-angle light scattering, the quality control of biological pharmaceuticals is possible.
  • 5.6K
  • 26 Apr 2022
Topic Review
Dry Sanitation Systems
Dry sanitation systems (waterless or composting toilets) have been used since the 1970s. Their use has received acceptance in rural regions of Europe and the United States. Some of the advantages of dry sanitation systems include their waterless nature, their low energy requirement and the creation of fertilizer as an added value product. Moreover, the use of such a system is a sustainable sanitation approach that may reduce the burden on infrastructure and provide sanitation to the 2.5 billion people worldwide who do not currently have access to it. The critical factors when choosing a dry sanitation system and their optimum parameters include aeration, moisture content (50%–60%), temperature (40–65 °C), carbon to nitrogen ratio (25–35), pH (5.5–8.0) and porosity (35%–50%). The temperature–time criterion approach is the most common method used to evaluate the stability and safety of the compost as a fertilizer. The risks of handling the waste after 12 months of composting have been calculated as low.
  • 5.6K
  • 27 Oct 2020
Topic Review
Artificial Intelligence in Water Treatment and Monitoring
Artificial-intelligence methods and machine-learning models have demonstrated their ability to optimize, model, and automate critical water- and wastewater-treatment applications, natural-systems monitoring and management, and water-based agriculture such as hydroponics and aquaponics. In addition to providing computer-assisted aid to complex issues surrounding water chemistry and physical/biological processes, artificial intelligence and machine-learning (AI/ML) applications are anticipated to further optimize water-based applications and decrease capital expenses. Poor data management, low explainability, poor model reproducibility and standardization, as well as a lack of academic transparency are all important hurdles to overcome in order to successfully implement these intelligent applications. Recommendations to aid explainability, data management, reproducibility, and model causality are offered in order to overcome these hurdles and continue the successful implementation of these powerful tools. 
  • 5.6K
  • 01 Jul 2022
Topic Review
Urban-Resilience Computation Simulation
Urban resilience refers to the ability of an urban system to withstand, absorb, recover, and adapt to man-made or natural disturbances and to learn timely control of current and future expectations. Simulating the dynamic process of urban resilience and analyzing the mechanism of resilience-influencing factors are of great significance to improve the intelligent decision-making ability of resilient urban planning. 
  • 5.6K
  • 19 Oct 2022
Topic Review Peer Reviewed
Low-Pressure Turbine Cooling Systems
Modern low-pressure turbine engines are equipped with casings impingement cooling systems. Those systems (called Active Clearance Control) are composed of an array of air nozzles, which are directed to strike turbine casing to absorb generated heat. As a result, the casing starts to shrink, reducing the radial gap between the sealing and rotating tip of the blade. Cooling air is delivered to the nozzles through distribution channels and collector boxes, which are connected to the main air supply duct. The application of low-pressure turbine cooling systems increases its efficiency and reduces engine fuel consumption.
  • 5.6K
  • 13 Apr 2022
Topic Review
Deriving the Schwarzschild Solution
The Schwarzschild solution describes spacetime under the influence of a massive, non-rotating, spherically symmetric object. It is considered by some to be one of the simplest and most useful solutions to the Einstein field equations.
  • 5.6K
  • 18 Oct 2022
Topic Review
Anthrozoology
Anthrozoology is the interdisciplinary study of relationships between humans and other animals.
  • 5.6K
  • 01 Aug 2024
Topic Review
Ante-Nicene Period
The Ante-Nicene Period (literally meaning "before Nicaea") of the history of early Christianity was the period following the Apostolic Age of the 1st century down to the First Council of Nicaea in 325. This period of Christian history had a significant impact on the unity of doctrine across all Christendom and the spreading of Christianity to a greater area of the world. Those seen as prominent figures of this era, referred to as the Ante-Nicene Fathers or Proto-orthodox Christians, generally agreed on most doctrine while the teachings of those early Christian writers which the general majority considered to be heretical, were rejected.
  • 5.6K
  • 14 Oct 2022
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