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Topic Review
Block Copolymers
With the speedy progress in the research of nanomaterials, self-assembly technology has captured the high-profile interest of researchers because of its simplicity and ease of spontaneous formation of a stable ordered aggregation system. The self-assembly of block copolymers can be precisely regulated at the nanoscale to overcome the physical limits of conventional processing techniques. This bottom-up assembly strategy is simple, easy to control, and associated with high density and high order, which is of great significance for mass transportation through membrane materials.
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  • 15 Nov 2022
Topic Review
Antimicrobial Peptides’ Natural Source
Antimicrobial peptides are made by lower and higher organisms responding to pathogenic challenges. Antimicrobial peptides (AMPs) kill the invading pathogens and modulate the innate immune response. They are commonly classified according to their sources, amino-acid-rich species, structural characteristics, and activities. In multicellular organisms and humans, they are localized into specific sites commonly exposed to microbes (i.e., mucosa epithelia and skin).
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  • 15 Nov 2022
Topic Review
Radical
In chemistry, a free radical is an atom, molecule, or ion that has at least one unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most organic radicals have short lifetimes. A notable example of a radical is the hydroxyl radical (HO·), a molecule that has one unpaired electron on the oxygen atom. Two other examples are triplet oxygen and triplet carbene (꞉CH2) which have two unpaired electrons. Radicals may be generated in a number of ways, but typical methods involve redox reactions. Ionizing radiation, heat, electrical discharges, and electrolysis are known to produce radicals. Radicals are intermediates in many chemical reactions, more so than is apparent from the balanced equations. Radicals are important in combustion, atmospheric chemistry, polymerization, plasma chemistry, biochemistry, and many other chemical processes. A majority of natural products are generated by radical-generating enzymes. In living organisms, the radicals superoxide and nitric oxide and their reaction products regulate many processes, such as control of vascular tone and thus blood pressure. They also play a key role in the intermediary metabolism of various biological compounds. Such radicals can even be messengers in a process dubbed redox signaling. A radical may be trapped within a solvent cage or be otherwise bound.
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  • 15 Nov 2022
Topic Review
Plastic Roads
Plastic roads are made entirely of plastic or of composites of plastic with other materials. Plastic roads are different from standard roads in the respect that standard roads are made from asphalt concrete, which consists of mineral aggregates and asphalt.
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  • 15 Nov 2022
Topic Review
Tyrocidine
Tyrocidine is a mixture of cyclic decapeptides produced by the bacteria Bacillus brevis found in soil. It can be composed of 4 different amino acid sequences, giving tyrocidine A–D. Tyrocidine is the major constituent of tyrothricin, which also contains gramicidin. Tyrocidine was the first commercially available antibiotic, but has been found to be toxic toward human blood and reproductive cells. The function of tyrocidine within its host B. brevis is thought to be regulation of sporulation. Tyrocidines A, B, and C are cyclic decapeptides. The biosynthesis of tyrocidine involves three enzymes. Parts of its sequence are identical to gramicidin S.
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  • 15 Nov 2022
Topic Review
Kokum Oil
Kokum oil comes from the seeds of the kokum tree (Garcinia indica). This fruit-bearing tree is also known as the wild mangosten tree, and also the red mangosten tree. This tree belongs to the Guttiferae family of the plant kingdom. Its scientific name is Garcinia indica. The oil extracted from the seeds is edible, and it can also be used for things other than cooking.
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  • 15 Nov 2022
Topic Review
Fanjul Brothers
The Fanjul brothers — Cuban born Alfonso "Alfy" Fanjul Jr., José "Pepe" Fanjul, Alexander Fanjul, and Andres Fanjul — are owners of Fanjul Corp., a vast sugar and real estate conglomerate in the United States and the Dominican Republic. It comprises the subsidiaries Domino Sugar, Florida Crystals, C&H Sugar, Redpath Sugar, former Tate & Lyle sugar companies, American Sugar Refining, La Romana International Airport, and resorts surrounding La Romana, Dominican Republic.
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  • 15 Nov 2022
Biography
Aimé Argand
François Pierre Ami Argand (5 July 1750 – 24 October 1803[1]) was a Genevan physicist and chemist. He invented the Argand lamp, a great improvement on the traditional oil lamp.[2] Francois Pierre Ami Argand was born in Geneva, Switzerland, the ninth of ten children. His father was a watchmaker, who intended for him to enter the clergy. However, he had an aptitude more for science, and beca
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  • 14 Nov 2022
Biography
Jack H. Freed
Jack H. Freed (born April 19, 1938) is an American chemist known for his pioneering work in electron paramagnetic resonance (aka electron spin resonance) spectroscopy. He is the Frank and Robert Laughlin Professor of Physical Chemistry, Emeritus, at Cornell University in Ithaca, New York. Jack Freed was born in New York City. He received his bachelor's degree in chemical engineering in 1958 f
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  • 14 Nov 2022
Topic Review
Supercritical CO2 Foaming Technologies
Poly(lactic acid) (PLA) foaming is divided into physical foaming and chemical foaming; in contrast with the latter, the use of a physical foaming agent for PLA foaming has the characteristic of being green and non-polluting in line with the current carbon-neutral development plan. At the same time, the foam obtained by physical foaming has the properties of lightweight, low density, and more stable. Common physical blowing agents are CO2 and N2. Due to the plasticizing effect of CO2, and its high solubility in PLA, which can promote the crystallization of PLA, the current research on the supercritical foaming of PLA, especially intermittent foaming, mainly uses CO2 as the preferred foaming agent. However, due to the fast diffusion rate of N2, smaller bubbles can be obtained in microcellular injection foaming using N2. Therefore, N2 is commonly used as a blowing agent in the microcellular injection foaming process. In the supercritical foaming process, foaming parameters, such as saturation temperature, saturation pressure, and saturation time have a great influence on the structure and properties of the bubble pores. The cell diameter, cell density, and foam volume expansion ratio are three fundamental parameters for characterizing the cell structure. The variation in the three parameters has a great influence on the cell structure and the performance of the foam. Cell diameter generally refers to the average diameter of at least 100 cell units in the foaming image obtained from electron microscopy. Cell density refers to the number of cells per cubic centimeter of the foamed sample. Volume expansion ratio refers to the density ratio of the unfoamed sample to the foamed sample.
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  • 14 Nov 2022
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