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Topic Review
Shade Covers in Water Reservoirs
Shade objects are small plastic spheres, squares or even hexagons floating on top of a water reserve for environmental reasons. The creator of shade balls in California originally used them to prevent chemical treatments in the reservoir from reacting with sunlight creating bromate, which is a carcinogen regulated by many institutions worldwide (chlorine plus sunlight turns bromine into bromate that is a potentially cancer-causing agent; because shady objects stop bromate from forming below, less chlorine is required to treat the water than without them). More recently, other environmental issues have been associated to the use of shade objects: slowing down water evaporation, preventing algae blooms, avoiding birds landing on bodies of water and promote water heating.
  • 899
  • 21 Oct 2021
Topic Review
Polymer Nanocomposites
PE and PVC Polymer nanocomposites used in underground cables have been of great interest to researchers over the past 10 years.
  • 899
  • 31 Dec 2020
Topic Review
Nuclear Resonance Vibrational Spectroscopy
Nuclear resonant vibrational spectroscopy (NRVS) is a synchrotron radiation (SR)-based nuclear inelastic scattering spectroscopy that measures the phonons (i.e., vibrational modes) associated with the nuclear transition. It has distinct advantages over traditional vibration spectroscopy and has wide applications in physics, chemistry, bioinorganic chemistry, materials sciences, and geology, as well as many other research areas.
  • 898
  • 17 Aug 2021
Topic Review
Hypopigmentation Mechanisms of Anti-Tyrosinase Peptides from Food Proteins
Skin hyperpigmentation resulting from excessive tyrosinase expression has long been a problem for beauty lovers, which has not yet been completely solved. Although researchers are working on finding effective tyrosinase inhibitors, most of them are restricted, due to cell mutation and cytotoxicity. Therefore, functional foods are developing rapidly for their good biocompatibility. Food-derived peptides have been proven to display excellent anti-tyrosinase activity, and the mechanisms involved mainly include inhibition of oxidation, occupation of tyrosinase’s bioactive site and regulation of related gene expression. For anti-oxidation, peptides can interrupt the oxidative reactions catalyzed by tyrosinase or activate an enzyme system, including super-oxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) to scavenge free radicals that stimulate tyrosinase. In addition, researchers predict that peptides probably occupy the site of the substrate by chelating with copper ions or combining with surrounding amino acid residues, ultimately inhibiting the catalytic activity of tyrosinase.
  • 897
  • 06 May 2022
Topic Review
Carbon-LiFePO4 Cathodes for Lithium-Ion Batteries
Li-ion batteries are in demand due to technological advancements in the electronics industry; thus, expanding the battery supply chain and improving its electrochemical performance is crucial. Carbon materials are used to increase the cyclic stability and specific capacity of cathode materials, which are essential to batteries. LiFePO4 (LFP) cathodes are generally safe and have a long cycle life. However, the common LFP cathode has a low inherent conductivity, and adding a carbon nanomaterial significantly influences how well it performs electrochemically.
  • 897
  • 28 Nov 2022
Topic Review
Scanning Electrochemical Microscopy Applied to Metals and Coatings
Scanning electrochemical microscopy (SECM) is a scanning probe microscope (SPM) technique based on electrochemical principles that allows chemical imaging of materials with spatial resolution. The movement of a microelectrode (ME) in close proximity to the interface allows the application of various experimental procedures that can be classified into amperometric and potentiometric operations depending on either sensing faradaic currents or probe potential values due to concentration distributions resulting from the corrosion process, as sketched in. In addition, alternating current signals can be applied to the ME, leading to AC-operation modes.
  • 896
  • 23 May 2022
Topic Review
Parameters Affecting Zeolite T Crystallization
Zeolites are well-known porous crystal systems that exist in various sizes (nano-, micro-, etc.) and have been widely incorporated in different applications. They consist of a uniform size of pore distributions which are also known as voids. Voids and cavities within the zeolite system are the factors that contribute to the unique properties of the zeolite. These voids and cavities are controlled by the type of crystals that grow and intergrowth within the zeolite membrane. Nanoporous zeolite T is identified to have within it an intergrowth framework that makes zeolite type T an exceptional species in the zeolite family.
  • 896
  • 18 Jun 2021
Topic Review
Albumin Conjugates as MRI Agents
Human serum albumin (HSA) is the most abundant protein in plasma. It is found at a concentration of roughly 0.7 mM in the vasculature. HSA is a monomeric multidomain biomolecule, representing the main determinant of plasma oncotic pressure and displays an extraordinary ligand binding capacity. HSA represents the main carrier for fatty acids, affects the pharmacokinetics of many drugs, can be a platform for drug discovery, suitable transport for therapy and diagnostics. Here we develop a class of macromolecular constructs from nitroxides conjugated to a human carrier protein as potential Organic radical contrast agents (ORCAs) for magnetic resonance imaging (MRI). MRI is a powerful non-invasive tool for clinics. The MRI specificity can be improved by enhancing by the addition of a contrast agent. The most efficient of the currently-used contrast agents are paramagnetic gadolinium chelates. However, the low stability of some chelates and therefore release toxic metal ions from the chelates provide harmful oxidative stress, mitochondrial membrane dysfunction, changes in gene expression, DNA damage, mutagenicity, etc. Therefore, there is sufficient interest in the production of “metal-free” MRI contrast agents.
  • 895
  • 29 Dec 2021
Topic Review
Melissa officinalis
Melissa officinalis is a medicinal plant rich in biologically active compounds which is used worldwide for its therapeutic effects. Chemical studies on its composition have shown that it contains mainly flavonoids, terpenoids, phenolic acids, tannins, and essential oil. The main active constituents of Melissa officinalis are volatile compounds (geranial, neral, citronellal and geraniol), triterpenes (ursolic acid and oleanolic acid), phenolic acids (rosmarinic acid, caffeic acid and chlorogenic acid), and flavonoids (quercetin, rhamnocitrin, and luteolin). 
  • 894
  • 06 Apr 2022
Topic Review
Surface Attached Mortar for Recycled Coarse Aggregate
Due to the large amount of old hardened cement mortar attached to the surface of aggregate and the internal micro-cracks formed by the crushing process, the water absorption, apparent density, and crushing index of recycled coarse aggregate are still far behind those of natural coarse aggregate. The results showed that the physical strengthening technique can remove old hardened mortar and micro powder attached to the surface of recycled coarse aggregate by mechanical action, which can effectively improve the quality of recycled coarse aggregate. 
  • 893
  • 04 Jan 2022
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