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Topic Review
Mass Concentration
In chemistry, the mass concentration ρi (or γi) is defined as the mass of a constituent mi divided by the volume of the mixture V. For a pure chemical the mass concentration equals its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixture. This explains the usage of ρ (the lower case Greek letter rho), the symbol most often used for density.
  • 1.8K
  • 12 Oct 2022
Topic Review
Pi-Stacking
In chemistry, pi stacking (also called π–π stacking) refers to the presumptive attractive, noncovalent interactions (orbital overlap) between the pi bonds of aromatic rings. However this is a misleading description of the phenomena since direct stacking of aromatic rings (the "sandwich interaction") is electrostatically repulsive. What is more commonly observed (see figure to the right) is either a staggered stacking (parallel displaced) or pi-teeing (perpendicular T-shaped) interaction both of which are electrostatic attractive For example, the most commonly observed interactions between aromatic rings of amino acid residues in proteins is a stagered stacked followed by a perpendular orientation. Sandwiched orientations are relatively rare. Pi stacking is repulsive as it places carbon atoms with partial negative charges from one ring on top of other partial negatively charged carbon atoms from the second ring and hydrogen atoms with partial postive charges on top of other hydrogen atoms that likewise carry partial positive charges. In staggered stacking, one of the two aromatic rings is offset sideways so that the carbon atoms with partial negative charge in the first ring are placed above hydrogen atoms with partial positive charge in the second ring so that the electrostatic interactions become attractive. Likewise, pi-teeing interactions in which the two rings are oriented perpendicultar to either other is electrostatically attractive as it places partial postively charged hydrogen atoms in close proximity to partially negatively charged carbon atoms. An alternative explanation for the preference for staggered stacking is due to the balance between van der Waals interactions (attractive dispersion plus Pauli repulsion). These staggered stacking and π-teeing interactions between aromatic rings are important in nucleobase stacking within DNA and RNA molecules, protein folding, template-directed synthesis, materials science, and molecular recognition. Despite the wide use of term pi stacking in the scientific literature, there is no theoretical justification for its use.
  • 12.9K
  • 12 Oct 2022
Topic Review
Tellurophenes
Tellurophenes are the tellurium analogue of thiophenes and selenophenes.
  • 377
  • 12 Oct 2022
Topic Review
Carbon Quantum Dots and Graphene Quantum Dots
Carbon quantum dots (CQDs) are small carbon NPs with a size less than 10 nm having excellent conductivity, chemical stability, environmental friendliness, high photostability, broadband optical absorption, low toxicity, photobleaching resistance, high surface area, and ease of modification. Graphene quantum dots (GQDs) are two-dimensional nanocrystals composed of small graphene particles with lateral diameters less than 100 nm. 
  • 2.0K
  • 12 Oct 2022
Topic Review
Microfluidic Synthesis of Halide Perovskite
Halide perovskites are increasingly exploited as semiconducting materials in diverse optoelectronic applications, including light emitters, photodetectors, and solar cells. The halide perovskite can be easily processed in solution, making microfluidic synthesis possible. 
  • 364
  • 12 Oct 2022
Topic Review
Enzymatic Interesterification
Enzymatic Interesterification (EIE) is the catalytic reaction that occurs when an enzyme is introduced into oil and rearranges the fatty acids on the glycerol backbone of a triglyceride. Triglycerides are either liquid or solid at room temperature. The rearrangement of the fatty acids that occurs with enzymatic interesterification provides structure and functionality to triglycerides at room temperature. This process adjusts the melting properties, increasing functionality and plasticity in food production applications. One of five different ways of altering melting property profiles, enzymatic interesterification is unlike the more widely used partial hydrogenation method in that it produces no trans fatty acids and lowers saturated fat content.
  • 1.9K
  • 12 Oct 2022
Topic Review
Application of Nanomaterials to Control Cell Behavior
Selective cancer therapy comes from the background of treating cancer cells with nanomaterials and applying light to the NPs. The research on “photo-nano-therapy” has been dramatically increasing since 2010. Photothermal therapies (PTT) has two diverse levels: (1) active or passive tumor homing through engineered phototherapeutic agents such as NPs; (2) irradiating the diseased lesion without harming the normal cells by the controlled light application. 
  • 467
  • 12 Oct 2022
Topic Review
Peroxyacetic Acid Pretreatment in Lignocellulose Biorefinery
The stubborn and complex structure of lignocellulose hinders the valorization of each component of cellulose, hemicellulose, and lignin in the biorefinery industries. Therefore, efficient pretreatment is an essential and prerequisite step for lignocellulose biorefinery. A considerable number of studies have focused on peroxyacetic acid (PAA) pretreatment in lignocellulose fractionation and some breakthroughs have been achieved in recent decades. 
  • 991
  • 12 Oct 2022
Topic Review
Application of Biobased Solvents in Asymmetric Catalysis
The application of the so-called green solvents has emerged as a useful alternative to the classical organic solvents. These solvents must present some properties, such as a low vapor pressure and toxicity, high boiling point and biodegradability, and must be obtained from renewable sources.
  • 553
  • 12 Oct 2022
Topic Review
Phase Change Materials for Thermal Regulative Wood-Based Products
Wood is an excellent building material or component that has been used all over the world. The rise in energy consumption worldwide, particularly in the building sector, has led to the development of diverse methods to overcome this problem. Embedding phase change material, phase change material (PCM), into the wood has been researched as one of the most effective alternatives of controlling the thermal loads of wood, as it can store and release latent heat energy at a specific temperature range.
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