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Topic Review
Snail Shell Waste in Food Industries
Effective waste management has become an urgent societal challenge. Food waste is made up of items meant for human consumption that are lost, polluted, disposed of, or deteriorated; the reutilization of shells from mollusk waste is a severe problem in terms of environmental protection and the development of the circular economy. The properties of waste shells are presented and discussed, including their biological–natural origin and high calcium carbonate content. This could add social and innovation focus on shell waste management, getting a non-toxic, eco-sustainable, low-cost, biodegradable supplement to invest in. Furthermore, it has the potential to support the circular economy approach by creating a closed system that minimizes the use of natural resources and environmental contamination. 
  • 1.9K
  • 19 Mar 2024
Topic Review
Symbol
In chemistry, a symbol is an abbreviation for a chemical element. Symbols for chemical elements normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised. Earlier symbols for chemical elements stem from classical Latin and Greek vocabulary. For some elements, this is because the material was known in ancient times, while for others, the name is a more recent invention. For example, Pb is the symbol for lead (plumbum in Latin); Hg is the symbol for mercury (hydrargyrum in Greek); and He is the symbol for helium (a new Latin name) because helium was not known in ancient Roman times. Some symbols come from other sources, like W for tungsten (Wolfram in German) which was not known in Roman times. A 3-letter temporary symbol may be assigned to a newly synthesized (or not-yet synthesized) element. For example, "Uno" was the temporary symbol for hassium (element 108) which had the temporary name of unniloctium, based on its atomic number being 8 greater than 100. There are also some historical symbols that are no longer officially used. In addition to the letters for the element itself, additional details may be added to the symbol as superscripts or subscripts a particular isotope, ionization, or oxidation state, or other atomic detail. A few isotopes have their own specific symbols rather than just an isotopic detail added to their element symbol. Attached subscripts or superscripts specifying a nuclide or molecule have the following meanings and positions: In Chinese, each chemical element has a dedicated character, usually created for the purpose (see Chemical elements in East Asian languages). However, Latin symbols are also used, especially in formulas. Many functional groups also have their own chemical symbol, e.g. Ph for the phenyl group, and Me for the methyl group. A list of current, dated, as well as proposed and historical signs and symbols is included here with its signification. Also given is each element's atomic number, atomic weight, or the atomic mass of the most stable isotope, group and period numbers on the periodic table, and etymology of the symbol. Hazard pictographs are another type of symbols used in chemistry.
  • 1.9K
  • 14 Nov 2022
Topic Review
Diversity of Synthetic Dyes
Synthetic dyes are mostly derived from petrochemical compounds, they are commercialized in liquid, powder, pastes, or granule forms. They are endowed with multiple potentialities such as fast and consistent coloration with different classes of fabrics as mentioned in the above section, a wide range of color pigments and shades, facility of manipulation, stability over several external factors and economical energy consumption. Therefore, the majority of synthetic dyes cause harmful impacts when discharged in non-treated or partially treated forms in the environment.
  • 1.9K
  • 06 Aug 2021
Topic Review
Manufacturing Sectors Supply Chain 4.0
The search for sustainability in the Supply Chain (SC) is one of the tasks that most concerns business leaders in all manufacturing sectors because of the importance that the Supply Chain has as a transversal tool and due to the leading role that it has been playing lately.
  • 1.9K
  • 18 Dec 2020
Topic Review
Crossover Effect in Cement-Based Materials
Cement-based materials (CBMs) such as pastes, mortars and concretes are the most frequently used building materials in the present construction industry. Cement hydration, along with the resulting compressive strength in these materials, is dependent on curing temperature, methods and duration. A concrete subjected to an initial higher curing temperature undergoes accelerated hydration by resulting in non-uniform scattering of the hydration products and consequently creating a great porosity at later ages. This phenomenon is called crossover effect (COE). The COE may occur even at early ages between seven to 10 days for Portland cements with various mineral compositions. Compressive strength and other mechanical properties are important for the long life of concrete structures, so any reduction in these properties is of great concern to engineers.  COE phenomenon was reported in the literature. However, based on the data reported in some papers, COE could be observed while the authors did not highlight and discuss this phenomenon in the publications.  This study is a broad literature review on this phenomenon based on the existing published papers and try to identify this phenomenon in the other published papers those could not discover and discuss about it in the study. In addition, this paper tries to further explain about COE, reason and mechanisms and methods to overcome this drawback in concrete/mortar.    
  • 1.8K
  • 25 Oct 2020
Topic Review
Crossover Experiment
In chemistry, a crossover experiment is a method used to study the mechanism of a chemical reaction. In a crossover experiment, two similar but distinguishable reactants simultaneously undergo a reaction as part of the same reaction mixture. The products formed will either correspond directly to one of the two reactants (non-crossover products) or will include components of both reactants (crossover products). The aim of a crossover experiment is to determine whether or not a reaction process involves a stage where the components of each reactant have an opportunity to exchange with each other. The results of crossover experiments are often straightforward to analyze, making them one of the most useful and most frequently applied methods of mechanistic study. In organic chemistry, crossover experiments are most often used to distinguish between intramolecular and intermolecular reactions. Inorganic and organometallic chemists rely heavily on crossover experiments, and in particular isotopic labeling experiments, for support or contradiction of proposed mechanisms. When the mechanism being investigated is more complicated than an intra- or intermolecular substitution or rearrangement, crossover experiment design can itself become a challenging question. A well-designed crossover experiment can lead to conclusions about a mechanism that would otherwise be impossible to make. Many mechanistic studies include both crossover experiments and measurements of rate and kinetic isotope effects.
  • 1.8K
  • 28 Oct 2022
Topic Review
Leucoagaricus gongylophorus and Leaf-Cutting Ants
Leaf-cutting ants are eusocial insects, as they show a highly developed social structure, manifesting ecological relationships. Their complex structure is characterized by an organized social behavior, the cultivation of a fungus garden and high levels of hygiene, which hinders the management of leaf-cutting ants compared to other insects. Leaf-cutting ants cause damage in agricultural and silviculture areas, mainly in monocultures.
  • 1.8K
  • 21 Apr 2022
Topic Review
Exchange Bias
The exchange bias (EB) is an effect occurring in coupled ferromagnetic/antiferromagnetic materials of diverse shapes, from core–shell nanoparticles to stacked nanostructures and thin films.
  • 1.8K
  • 18 Feb 2021
Topic Review
Sustainable Catalytic Pyranopyrazole Scaffolds’ Synthesis
Heterocycles are important components of many natural materials and are extremely valuable in organic and medicinal chemistry. Among the heterocyclic entities, pyranopyrazole moieties have demonstrated remarkable biochemical behaviours and activities which provide a versatile skeleton for drug innovation. Hence, many nitrogen-based, fused structures have been incorporated as building blocks of various pharmacological potent scaffolds. Pyranopyrazoles are known for their anti-inflammatory, analgesic, antidiabetic, antimicrobial, cholinesterase-inhibiting, antibacterial and anticancer activities, as well as for their efficacy in treating Alzheimer’s disease. Because of this, several cost-effective synthetic protocols for synthesising pyranopyrazole derivatives—utilising less expensive substrates, reusable catalysts, and eco-friendly solvents—have been developed.
  • 1.8K
  • 10 Jun 2021
Topic Review
Hypoestrogenism
Hypoestrogenism, or estrogen deficiency, refers to a lower than normal level of estrogen. It is an umbrella term used to describe estrogen deficiency in various conditions. Estrogen deficiency is also associated with an increased risk of cardiovascular disease, and has been linked to diseases like urinary tract infections and osteoporosis. In women, low levels of estrogen may cause symptoms such as hot flashes, sleeping disturbances, decreased bone health, and changes in the genitourinary system. Hypoestrogenism is most commonly found in women who are postmenopausal, have primary ovarian insufficiency (POI), or are presenting with amenorrhea (absence of menstrual periods). Hypoestrogenism includes primarily genitourinary effects, including thinning of the vaginal tissue layers and an increase in vaginal pH. With normal levels of estrogen, the environment of the vagina is protected against inflammation, infections, and sexually transmitted infections. Hypoestrogenism can also occur in men, for instance due to hypogonadism. There are both hormonal and non-hormonal treatments to prevent the negative effects of low estrogen levels and improve quality of life.
  • 1.8K
  • 09 Nov 2022
Topic Review
Compounds of Lead
Compounds of lead exist in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) compounds are typically strong oxidants or exist only in highly acidic solutions.
  • 1.8K
  • 14 Nov 2022
Topic Review
Alpha-Amanitin
alpha-Amanitin or α-amanitin is a cyclic peptide of eight amino acids. It is possibly the most deadly of all the amatoxins, toxins found in several species of the mushroom genus Amanita, one being the death cap (Amanita phalloides) as well as the destroying angel, a complex of similar species, principally A. virosa and A. bisporigera. It is also found in the mushrooms Galerina marginata and Conocybe filaris. The oral -1">50 of amanitin is 100 μg/kg for rats. Unlike most cyclic peptides, amatoxins (and phallotoxins) are synthesized on ribosomes. The genes encoding the proprotein for α-amanitin belong to the same family as those that encode for phallacidin (a phallotoxin).
  • 1.8K
  • 14 Oct 2022
Topic Review
Non-Helical Models of DNA Structure
In the history of molecular biology, non-helical or "side-by-side" models of DNA were proposed in the 1970s as a challenge to the standard double-helical model. The non-helical models attempted to solve problems relating to the topology of circular DNA chromosomes during replication. These theories were briefly considered seriously as a minority viewpoint, but they were later largely rejected due to X-ray crystallography of DNA duplexes and later the nucleosome core particle, as well as the discovery of topoisomerases, and these non-double-helical models are not currently accepted by the mainstream scientific community.
  • 1.8K
  • 12 May 2023
Topic Review
Hydrogen Sulfide Corrosion in Oil and Gas Industries
In the oil and gas industry, the corrosion attributed to hydrogen sulfide (H2S) is one of the most significant challenges.
  • 1.8K
  • 26 Feb 2024
Topic Review
Salts Hydrates and Composites
Salt hydrates are alloys of salts and water. Salt hydrates display high theoretical energy densities, which are promising materials in thermal energy storage (TES).
  • 1.8K
  • 25 Jan 2022
Topic Review
Apricot Kernel By-Products and Their Value
Stone fruits, such as the apricot (Prunus armeniaca L.), are frequently consumed. As such, a substantial volume of apricot waste is generated at each stage of the food supply chain, including harvesting, processing, packaging, warehousing, transportation, retailing, and eventual consumption. Apricot kernels are recognized for their abundance of bioactive compounds, including polyphenols and tocopherols, which find utility in diverse sectors including cosmetology and the food industry. Both conventional and green methods are employed, and generally, green methods lead to higher extraction efficiency. The antimicrobial properties of apricot kernel essential oil have been widely recognized, leading to its extensive historical usage in the treatment of diverse ailments. In addition, apricot kernel oil possesses the capacity to serve as a viable resource for renewable fuels and chemicals.
  • 1.8K
  • 30 Jan 2024
Topic Review
Rheological Behavior of Cement Paste
The rheological behavior of cement paste displays several complexities such as non-linearity, yielding, time-dependence and chemical changes. The most common testing procedures allowing for the characterization of this behavior have been reported. For flow behavior, the most relevant protocol consists of the application of a ramp sweep (shear rate or shear stress) so that the flow curve (shear stress as a function of the shear rate) is at steady state flow. The structural build-up can be characterized by static yield stress measurements or the SAOS protocol for various resting times. The non-linearity of flow behavior corresponds to a shear-thinning/shear-thickening phenomenon that can be represented by the Herschel–Bulkley model. If the shear-thinning phenomenon can be related to the flocculation state, the origins of shear thickening are not clearly elucidated. Theories based on order–disorder transition, particle clustering, or viscous/inertial regime transition have been developed to explain the appearance of shear thickening. 
  • 1.8K
  • 17 Aug 2023
Topic Review
Meso-Zeaxanthin
Meso-zeaxanthin (3R,3´S-zeaxanthin) is a xanthophyll carotenoid, as it contains oxygen and hydrocarbons, and is one of the three stereoisomers of zeaxanthin. Of the three stereoisomers, meso-zeaxanthin is the second most abundant in nature after 3R,3´R-zeaxanthin, which is produced by plants and algae. To date, meso-zeaxanthin has been identified in specific tissues of marine organisms and in the macula lutea, also known as the "yellow spot", of the human retina.
  • 1.8K
  • 02 Dec 2022
Topic Review
Silver Nanoparticles for Waste Water Management
Rapidly increasing industrialisation has human needs, but the consequences have added to the environmental harm. The pollution caused by several industries, including the dye industries, generates a large volume of wastewater containing dyes and hazardous chemicals that drains industrial effluents. The growing demand for readily available water, as well as the problem of polluted organic waste in reservoirs and streams, is a critical challenge for proper and sustainable development. Remediation has resulted in the need for an appropriate alternative to clear up the implications. Nanotechnology is an efficient and effective path to improve wastewater treatment/remediation. The effective surface properties and chemical activity of nanoparticles give them a better chance to remove or degrade the dye material from wastewater treatment. AgNPs (silver nanoparticles) are an efficient nanoparticle for the treatment of dye effluent that have been explored in many studies. The antimicrobial activity of AgNPs against several pathogens is well-recognised in the health and agriculture sectors.
  • 1.8K
  • 05 May 2023
Topic Review
Microencapsulation Technology of Phycocyanin
Phycocyanin (PC) is a blue fluorescent protein with multi-bioactive functions. The multi-bioactivities and spectral stability of phycocyanin are susceptible to external environmental conditions, which limit its wide application. Microencapsulation is a micro-packaging technology that encapsulates trace substances with polymer films. Multifarious strategies have been successfully investigated for the microencapsulation of PC.
  • 1.8K
  • 28 Sep 2022
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