Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Conducting Poly(Methyl Methacrylate) (PMMA)
Poly(methyl methacrylate), PMMA is a lightweight insulating material that is known for its high Young's Modulus and good optical transmittance properties. Benefiting from these properties, there are recently vast interests to produce conducting PMMA for various applications including electronics, corrosion protective coatings,  diodes, sensors, and many more. Conducting PMMA is possible to produce by incorporating conducting polymers such as  polyaniline (PANi) by physical blending method or by co-polymerization technique. PANi has been the main choice to incorporate with PMMA due to its good conductivity, better environmental stability, and good redox reversibility. In addition, the limitations of PANi include poor adhesion, low mechanical stability and, limited solubility in most organic solvents can be surpassed by blending or co-polymerizing with thermoplastics such as PMMA.
  • 1.7K
  • 30 Jun 2021
Topic Review
Commercially Important Chlorinated Phenols
Phenols are compounds having a hydroxyl group attached to an aromatic ring such as a benzene or naphthalene ring. Several phenols that also possess one or more chlorine substituents attached to the aromatic ring have significant commercial importance, and these are the subject of this entry.
  • 1.7K
  • 08 Jan 2022
Topic Review
Red Seaweed Pigments
Algae taxa are notably diverse regarding pigment diversity and composition, red seaweeds (Rhodophyta) being a valuable source of phycobiliproteins (phycoerythrins, phycocyanin, and allophycocyanin), carotenes (carotenoids and xanthophylls), and chlorophyll a. These pigments have a considerable biotechnological potential, which has been translated into several registered patents and commercial applications. 
  • 1.7K
  • 20 Jan 2022
Topic Review
Starch–Mucilage Composite Films
Generally, starch is an edible carbohydrate complex, composed of a linear polymer, amylose (a linear molecule with few branches), and amylopectin (branched-chain molecule). Therefore, the presence of amylose in large quantities provides excellent strength while a high level of amylopectin is responsible for the reduction of the tensile strength during the production of a film. However, starch-based films have limitations in their ability to bear various environmental factors such as temperature, pressure, and natural gases during the handling due to their low strength, flexibility, rigidity, and high hydrophilic nature. To overcome this issue, the combination of starch and mucilage can be used as a binary polymer alternative to improve the mechanical properties of the packaging film. Additionally, the addition of several biopolymers such as cellulose, gum, and gelatin into a starch blend can change the network formation in the film matrix, improving the physicochemical and biological properties of the film. Moreover, mucilage is a water-soluble edible polysaccharide, extensively used in the food industry due to its excellent functional properties (antimicrobial, antioxidant, water-holding, oil holding, and foaming capacity), and diverse industrial applications such as thickening agent, binding agent, emulsifying agent, and suspending agent. Mucilage has a great potential to produce a stable polymeric network that confines the starch granules, which delay the release of amylose in resulting the improvement of the mechanical property of films.
  • 1.7K
  • 17 Aug 2021
Topic Review
Sulfur Mustard
Sulfur mustard, commonly known as mustard gas, is the prototypical substance of the sulfur-based family of cytotoxic and vesicant chemical warfare agents known as the sulfur mustards, which can form large blisters on exposed skin and in the lungs. They have a long history of use as a blister-agent in warfare and along with organoarsenic compounds are the most well-studied such agents. Related chemical compounds with similar chemical structure and similar properties form a class of compounds known collectively as sulfur mustards or mustard agents. Pure sulfur mustards are colorless, viscous liquids at room temperature. When used in impure form, such as warfare agents, they are usually yellow-brown and have an odor resembling mustard plants, garlic, or horseradish, hence the name. The common name of "mustard gas" is considered inaccurate because the sulfur mustard is not actually vaporized, but dispersed as a fine mist of liquid droplets. Sulfur mustard was originally assigned the name LOST, after the scientists Wilhelm Lommel and Wilhelm Steinkopf, who developed a method of large-scale production for the Imperial German Army in 1916. Mustard agents are regulated under the 1993 Chemical Weapons Convention. Three classes of chemicals are monitored under this Convention, with sulfur and nitrogen mustard grouped in Schedule 1, as substances with no use other than in chemical warfare. Mustard agents could be deployed by means of artillery shells, aerial bombs, rockets, or by spraying from warplanes or other aircraft. Sulfur mustard can be readily decontaminated through reaction with chloramine-T.
  • 1.7K
  • 11 Nov 2022
Topic Review
Synthesis of β-Lactams
Stereoselective synthesis of cis and trans β-lactams under diverse conditions is performed.  Numerous conditions are used for this study. The formation of β-lactam depends on the conditions of the experiments, structures of the imines and acid chlorides, order of addition of the reagents, reaction temperature, and solvents. A few mathematical graphs are plotted to explain the results.   
  • 1.7K
  • 25 Nov 2020
Topic Review
Graphene and Graphene-Related Materials
Graphene is the most outstanding material among the new nanostructured carbonaceous species discovered and produced. Graphene’s astonishing properties (i.e., electronic conductivity, mechanical robustness, large surface area) have led to a deep change in the material science field.
  • 1.7K
  • 17 Mar 2021
Topic Review
Antimicrobial Polymers
Antibiotic resistance has increased markedly in Gram-negative bacteria, causing severe infections intractable with traditional drugs and amplifying mortality and healthcare costs. Consequently, to find novel antimicrobial compounds, active on multidrug resistant bacteria, is mandatory. In this regard, cationic antimicrobial peptides (CAMPs)—able to kill pathogens on contact—could represent an appealing solution. However, low selectivity, hemolytic toxicity and cost of manufacturing, hamper their massive clinical application. In the recent years—starting from CAMPs as template molecules—less toxic and lower-cost synthetic mimics of CAMPs, including cationic peptides, polymers and dendrimers, have been developed. Although the pending issue of hemolytic toxicity and biodegradability is still left not completely solved, cationic antimicrobial polymers (CAPs), compared to small drug molecules, thanks to their high molecular weight, own appreciable selectivity, reduced toxicity toward eukaryotic cells, more long-term activity, stability and non-volatility. With this background, an updated overview concerning the state of the art of the main manufactured types of CAPs, active on Gram-negative bacteria, is herein reported, including synthetic procedure and action’s mechanism. Information about the antibacterial activity, advantages and drawbacks of the most appealing compounds was also provided.
  • 1.7K
  • 12 Jan 2021
Topic Review
Cell Wall Polysaccharides in Gram-Positive and Gram-Negative Bacteria
Certain bacteria constitute a threat to humans due to their ability to escape host defenses as they easily develop drug resistance. Bacteria are classified into gram-positive and gram-negative according to the composition of the cell membrane structure. Gram-negative bacteria have an additional outer membrane (OM) that is not present in their gram-positive counterpart; the latter instead hold a thicker peptidoglycan (PG) layer. Bacterial resistance to these drugs continues to evolve, which calls for novel antibacterial approaches to be developed.
  • 1.7K
  • 05 Aug 2022
Topic Review
Bacterial Nanocellulose
Bacterial nanocellulose (BNC) is a biomaterial with a growing interest in the field of nanocomposites and sustainable materials. It is produced through fermentative processes by several species of bacteria as extracellular secretion. BNC looks like a highly pure and flexible 3D porous network suitable for various applications including biodegradable materials, reinforcing agents, packaging films, transpiring membranes, and medical devices. Among the many applications, the use of BNC functionalized with organic and inorganic groups has found wide use as a catalyst in chemical transformations.
  • 1.7K
  • 25 Jan 2021
  • Page
  • of
  • 465
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Video Production Service
Feedback