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Topic Review
C-,N- and S-Doped TiO2 Photocatalysts
This entry describes the basics of photocatalysis. It also presents properties and applications of C-,N- and S-Doped TiO2 as a photocatalyst.
  • 887
  • 28 May 2021
Topic Review
C-C and C-Heteroatom Bonds Construction
Acyl-containing organic compounds, including ketones, esters, amides, and so forth, are a huge library of widespread chemical feedstocks which play a vital role in countless fields such as pharmaceuticals, natural products, advanced materials, and fine chemicals.
  • 495
  • 28 Dec 2022
Topic Review
C–H Functionalisation
C–H bond functionalisation describes the transformation of a C-H bonds into a C-X bonds (X = C, N, O, B, halides, among many others). The term is typically associated with transition metals in processes like C-H activation. However, other methods such as nitrene/carbene insertion and hydrogen atom transfer (HAT) can also be used to functionalise C-H bonds with varying selectivity and ability to introduce different functional groups depending on the method used. 
  • 347
  • 09 Nov 2023
Topic Review
C,C- and C,N-Chelated Organocopper Compounds
Copper-catalyzed and organocopper-involved reactions are of great significance in organic synthesis. To have a deep understanding of the reaction mechanisms, the structural characterizations of organocopper intermediates become indispensable. Meanwhile, the structure-function relationship of organocopper compounds could advance the rational design and development of new Cu-based reactions and organocopper reagents. Compared to the mono-carbonic ligand, the C,N- and C,C-bidentate ligands better stabilize unstable organocopper compounds. Bidentate ligands can chelate to the same copper atom via η2-mode, forming a mono-cupra-cyclic compounds with at least one acute C-Cu-C angle. When the bidentate ligands bind to two copper atoms via η1-mode at each coordinating site, the bimetallic macrocyclic compounds will form nearly linear C-Cu-C angles. The anionic coordinating sites of the bidentate ligand can also bridge two metals via μ2-mode, forming organocopper aggregates with Cu-Cu interactions and organocuprates with contact ion pair structures. The reaction chemistry of some selected organocopper compounds is highlighted, showing their unique structure–reactivity relationships.
  • 672
  • 08 Oct 2021
Topic Review
CAD Algorithms for Adjusting Contours
In patients with atrophy of the temporalis muscle or flattened skin flaps (trephined syndrome), CAD/CAM (customized computer-assisted design/manufacturing)-fabricated implants with modified reconstructed curvature is crucial for cranioplasty. For the aforementioned clinical conditions, adequate scalp adaptation is significant for either the maintenance of soft tissue bulk or the prevention of the dead space between the dura and implant. This can thoroughly be achieved by adjusting CAD algorithms for the contouring of skull defects with outwardly elevation or inwardly depression, respectively. We herein demonstrate operative details involving modified contours for the reconstruction of skull defects in CAD Modeling.
  • 1.2K
  • 29 Oct 2020
Topic Review
CAD/CAM Ceramics
CAD/CAM ceramics present a promising alternative to metal-ceramic fixed dental prostheses.
  • 779
  • 23 Jun 2021
Topic Review
Cadmium Poisoning
Cadmium is a naturally occurring toxic metal with common exposure in industrial workplaces, plant soils, and from smoking. Due to its low permissible exposure in humans, overexposure may occur even in situations where trace quantities of cadmium are found. Cadmium is used extensively in electroplating, although the nature of the operation does not generally lead to overexposure. Cadmium is also found in some industrial paints and may represent a hazard when sprayed. Operations involving removal of cadmium paints by scraping or blasting may pose a significant hazard. The primary use of cadmium is in the manufacturing of NiCd rechargeable batteries. The primary source for cadmium is as a byproduct of refining zinc metal. Exposures to cadmium are addressed in specific standards for the general industry, shipyard employment, the construction industry, and the agricultural industry.
  • 424
  • 19 Oct 2022
Topic Review
Cadmium Recovery from Spent Ni-Cd Batteries
The significant increase in the demand for efficient electric energy storage during the last decade has promoted an increase in the production and use of Cd-containing batteries. On the one hand, the amount of toxic Cd-containing used batteries is growing, while on the other hand, Cd is on a list of critical raw materials (for Europe). Both of these factors call for the development of effective technology for Cd recovery from spent batteries. Alkaline nickel-cadmium (Ni-Cd) batteries are widely used as autonomous sources of industrial and household current (power banks) due to a successful combination of feasibility studies and achieved sustainable electrical characteristics. In recent decades, the market of secondary current sources for portable equipment has undergone significant changes, which leads to an intensive replacement of Ni-Cd batteries with lithium-ion (LIB) and nickel-metal-hydride.
  • 714
  • 07 Feb 2022
Topic Review
Calcium Carbonate as a Drugs Controlled Release Carrier
A drug carrier usually refers to a tool that can carry the effective ingredients of drugs into the human body. The drug-controlled release system prepared by a new drug carrier can allow the gradual release of the drug in the human body at a stable rate, thus decreasing the frequency of administration and reducing the toxicity and side effects thereof; however, existing drug carriers generally have problems such as low drug loading, poor biocompatibility, stability, and specificity, each of which could be improved. Calcium carbonate can be used as a sustained-release carrier of active substances, with good biocompatibility, biodegradability, low cost, easy preparation, and broad application prospects. 
  • 127
  • 28 Sep 2023
Topic Review
Calcium Orthophosphate-Based Bioceramics
Various types of materials have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A short time later, such synthetic biomaterials were called bioceramics. During the past, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the CaPO4-based implants would remain biologically stable once incorporated into the skeletal structure or whether they would be resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed, and such formulations became an integrated part of the tissue engineering approach. Now, CaPO4-based scaffolds are designed to induce bone formation and vascularization. These scaffolds are usually porous and harbor various biomolecules and/or cells.
  • 332
  • 30 Sep 2022
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