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Topic Review
Deep Eutectic Solvents
Deep eutectic solvents (DESs), were introduced in 2001 as an alternative to ILs. These showed a stronger ecofriendly profile, with easier and cheaper production, while having similar properties. DESs contain large, asymmetrical ions that have low lattice energy and, thus, low melting points. They are often acquired by the complexation of a quaternary ammonium salt with a metal salt or hydrogen bond donor (HBD). The charge delocalization occurring through hydrogen bonding between, for instance a halide ion and the hydrogen-donor moiety, is responsible for the decrease in the melting point of the mixture, in relation to the melting points of the individual components. Since 2001, many scientists around the globe pursed the utilization of DESs and published a variety of studies. The use of DESs in analytical microextraction techniques is on the rise, due to the many benefits they provide, such as lower cost and easier synthesis than ILs and an environmentally friendly profile, because of the low toxicity reported, although they need further investigation. To this day, the number of HBAs and HBDs is quite limited, so more studies ought to be carried out to present a plethora of DESs available for use. Moreover, DESs are not commercially available yet, substantially affecting and further limiting their usage for routine analyses in industrial or certified laboratories. The extraordinary high relative recoveries, selectivity, low LODs and decent repeatability they offer, render them appropriate for the determination and quantification of lots of compounds in either simple or complex matrices. As seen, most applications regard liquid phase microextractions rather than solid phase microextractions, because of their liquid nature, as it is simpler to use them as supporting solid adsorbents. The fact that the sample preparation of complicated matrices is of high interest makes them ideal for the research. Hopefully, DESs will be available for purchase in the foreseeable future and will replace organic solvents in some analytical methods commonly used nowadays, while more studies are carried out about their properties. Our aim in this review will be towards the use of DESs in analytical extraction and microextraction techniques, while briefly presenting some frequently used DESs, their synthesis methods and their properties. The ever-increasing use of deep eutectic solvents (DES) in microextraction techniques will be discussed, focusing on the reasons needed to replace conventional extraction techniques with greener approaches that follow the principles of green analytical chemistry.
  • 3.2K
  • 10 Feb 2021
Topic Review
Yan Tan Tethera
Yan Tan Tethera is a sheep-counting rhyme/system traditionally used by shepherds in Northern England and earlier in some other parts of Britain. Until the Industrial Revolution, the use of traditional number systems was common among shepherds, especially in the fells of the Lake District. The Yan Tan Tethera system was also used for counting stitches in knitting. The words derive from a Brythonic Celtic language. Though most of these number systems fell out of use by 1910, some are still in use. The word yan or yen for "one" in some northern English dialects generally represents a regular development in Northern English in which the Old English long vowel /ɑː/ was broken into /ie/, /ia/ and so on. This explains the shift to yan and ane from the Old English ān, which is itself derived from the Proto-Germanic *ainaz. Another example of this development is the Northern English word for "home", hame, which has forms such as hyem, yem and yam all deriving from the Old English hām.
  • 3.2K
  • 20 Nov 2022
Topic Review
Cylinder Block
The cylinder block is an integrated structure comprising the cylinder(s) of a reciprocating engine and often some or all of their associated surrounding structures (coolant passages, intake and exhaust passages and ports, and crankcase). The term engine block is often used synonymously with "cylinder block" (although technically distinctions can be made between en bloc cylinders as a discrete unit versus engine block designs with yet more integration that comprise the crankcase as well). In the basic terms of machine elements, the various main parts of an engine (such as cylinder(s), cylinder head(s), coolant passages, intake and exhaust passages, and crankcase) are conceptually distinct, and these items can all be made as discrete pieces that are bolted together. Such construction was very widespread in the early decades of the commercialization of internal combustion engines (1880s to 1920s), and it is still sometimes used in certain applications where it remains advantageous (especially very large engines, but also some small engines). However, it is no longer the normal way of building most petrol engines and diesel engines, because for any given engine configuration, there are more efficient ways of designing for manufacture (and also for maintenance and repair). These generally involve integrating multiple machine elements into one discrete part, and doing the making (such as casting, stamping, and machining) for multiple elements in one setup with one machine coordinate system (of a machine tool or other piece of manufacturing machinery). This yields lower unit cost of production (and/or maintenance and repair). Today most engines for cars, trucks, buses, tractors, and so on are built with fairly highly integrated design, so the words "monobloc" and "en bloc" are seldom used in describing them; such construction is often implicit. Thus "engine block", "cylinder block", or simply "block" are the terms likely to be heard in the garage or on the street.
  • 3.2K
  • 28 Sep 2022
Topic Review
Narcissistic Rage and Narcissistic Injury
Narcissistic rage is a psychological construct that describes a reaction to narcissistic injury, which is conceptualized as a perceived threat to a narcissist's self-esteem or self-worth. "Narcissistic injury"" (or "narcissistic scar") is a phrase used by Sigmund Freud in the 1920s; narcissistic wound and narcissistic blow are further, almost interchangeable terms. The term narcissistic rage was coined by Heinz Kohut in 1972. The model underlying the construct suggests that narcissistic injury occurs when a narcissist's elevated self-image or perception is threatened and feels that their hidden, "true self" has been revealed. This may be the case when the narcissist experiences a "fall from grace", such as when their hidden behaviors or motivations are revealed, or when their egotism is challenged or questioned. Narcissistic injury is a cause of distress and can lead to dysregulation of behaviors as in narcissistic rage. Narcissistic rage occurs on a continuum, which may range from instances of aloofness and expressions of mild irritation or annoyance to serious outbursts, including violent attacks and murder. Narcissistic rage reactions are not limited to personality disorders and may be also seen in catatonic, paranoid delusion and depressive episodes. It has also been suggested that narcissists have two layers of rage: the first layer can be thought of as a constant anger (towards someone else), with the second layer being a self-aimed wrath. Narcisistic pinballing is when a narcissists rage has been activated and they erratically seek supply from multiple sources to repair narcissistic injury and in aim of seeking vengeance and/or vindication against the individual who caused the rage.
  • 3.2K
  • 25 Nov 2022
Topic Review
Sexual Fetishism
Sexual fetishism or erotic fetishism is a sexual fixation on a nonliving object or nongenital body part. The object of interest is called the fetish; the person who has a fetish for that object is a fetishist. A sexual fetish may be regarded as a non-pathological aid to sexual excitement, or as a mental disorder if it causes significant psychosocial distress for the person or has detrimental effects on important areas of their life. Sexual arousal from a particular body part can be further classified as partialism. While medical definitions restrict the term sexual fetishism to objects or body parts, fetish can, in common discourse, also refer to sexual interest in specific activities.
  • 3.2K
  • 14 Oct 2022
Topic Review
Acetylcholinesterase Inhibitors
Acetylcholinesterase (AChE) inhibitors are the only drugs that have demonstrated success in slowing shrinkage (atrophy) of the cortex, hippocampus, and basal forebrain, major areas of Alzheimer's disease (AD)-associated brain damage and dementia. The main barrier to taking advantage of this new success in treating, or even preventing, AD is that the old available AChE inhibitors are weak reversible inhibitors that cause intolerable nausea, vomiting, and diarrhea if given in the higher doses needed. A promising new strategy for producing high-level AChE inhibition in the brain as needed for effective treatment of AD is the use of AChE inhibitors that are of a different type, the  irreversible inhibitors. 
  • 3.2K
  • 28 Oct 2020
Topic Review
Caffeine, a Factor for Osteoarthritis
Osteoarthritis (OA) is one of the most common and disabling rheumatic diseases. It is mainly characterized by articular cartilage degradation, which is fundamental for correct joint function, lubrication, and resistance to mechanical loading. However, the whole joint is normally compromised. As a result of the articular cartilage alterations, typical OA symptoms such as pain and joint failure appear, increasing population’s dependency. OA aetiology is not fully understood. However, there are some risk factors such as certain genetic profiles, gender, age, exercise, metabolic alterations, obesity and diet habits, which could increase its prevalence. Notably, diet can play a crucial role in OA onset and evolution. Specifically, it is known that caffeine intake exerts a negative impact on articular cartilage. Overall, there is ample evidence indicating that caffeine intake has a negative impact on the physiology of articular cartilage, increasing consumers predisposition to suffer OA. Considering these results, caffeine consumption should be reduced and closely controlled. Specifically, this control should be compulsory to those people whose caffeine metabolism is reduced, such as children and pregnant women.
  • 3.2K
  • 02 Nov 2020
Topic Review
Applications of Liquid Crystals-Based Sensors
Liquid crystals are a class of chemical substances that exist in intermediate states between crystalline solids and liquids. They thus share the anisotropic properties of crystalline solids as well as fluid properties of isotropic liquids. 
  • 3.2K
  • 23 Mar 2022
Topic Review
Cheese By-Products
Cheese whey (CW) is nowadays recognized as a source of functional and bioactive compounds, especially proteins and peptides. However, a large proportion of the whey produced worldwide is still not valorized. This results from the fact that small and medium size dairy industries lack dimension to make the necessary investments for CW valorization. In some countries such as Portugal, Spain, Italy and Turkey, CW is employed in the production of whey cheeses. The liquid remaining after whey cheese production represents more than 90% of the original whey and is called second cheese whey (SCW). SCW is a poorly studied by-product and there is little interest in its recovery. SCW is a poorly studied by-product and there is little interest in its recovery. Some authors studied the use of SCW for conversion into biofuel and as a biotechnological substrate for fermented products while others studied its potential for the production of fermented drinks. However, half of CW and almost all SCW are not valorized for human consumption. This review presents several alternatives for the valorization of both by-products.
  • 3.2K
  • 20 May 2021
Topic Review
Health-Promoting Beverages
Tea, a beverage made from the processed leaves of the tea plant, Camellia sinensis, and herbal infusions, were primarily consumed to their pleasant taste. Nowadays, are also consumed due to the existence of nutraceutical compounds in the herbs used, such as polyphenols.
  • 3.2K
  • 30 Oct 2020
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