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Topic Review
Biological Carbon Fixation
Biological carbon fixation or сarbon assimilation is the process by which inorganic carbon (particularly in the form of carbon dioxide) is converted to organic compounds by living organisms. The compounds are then used to store energy and as structure for other biomolecules. Carbon is primarily fixed through photosynthesis, but some organisms use a process called chemosynthesis in the absence of sunlight. Organisms that grow by fixing carbon are called autotrophs, which include photoautotrophs (which use sunlight), and lithoautotrophs (which use inorganic oxidation). Heterotrophs are not themselves capable of carbon fixation but are able to grow by consuming the carbon fixed by autotrophs or other heterotrophs. "Fixed carbon", "reduced carbon", and "organic carbon" may all be used interchangeably to refer to various organic compounds. Chemosynthesis is carbon fixation driven by chemical energy, rather than from sunlight. Sulfur- and hydrogen-oxidizing bacteria often use the Calvin cycle or the reductive citric acid cycle.
  • 754
  • 02 Dec 2022
Topic Review
Electrospun Nanofibers for Skin Tissue Engineering
Surface modification of electrospun products has been an attractive method for increasing multifunctionality and biocompatibility properties. 
  • 754
  • 29 Mar 2022
Topic Review
Precipitation
In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution. The solid formed is called the precipitate. In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant. The clear liquid remaining above the precipitated or the centrifuged solid phase is also called the 'supernate' or 'supernatant'. The notion of precipitation can also be extended to other domains of chemistry (organic chemistry and biochemistry) and even be applied to the solid phases (e.g., metallurgy and alloys) when solid impurities segregate from a solid phase.
  • 754
  • 07 Nov 2022
Topic Review
Electrochemical Determination of Kynurenine Pathway Metabolites
Kynurenine pathway (KP) is the major catabolic route of tryptophan, which generates an important enzyme cofactor (NAD+) and a variety of bioactive metabolites (so-called kynurenines) with immunosuppressive functions or neuroprotective, antioxidant, and toxic properties. It is involved in a variety of physiological processes, especially in conditions associated with immune dysfunction, central nervous system disorders, autoimmunity, infection, diabetes, and cancer. In normal conditions, tryptophan depletion via KP is initiated by the liver enzyme tryptophan 2,3-dioxygenase (TDO) and the extrahepatic enzyme - indoleamine 2,3-dioxygenase  (IDO) that contributes minimally to this process (5–10%). The extrahepatic KP becomes quantitatively more significant under conditions of immune activation. KP metabolites are frequently found in biofluids, tissues, and cell-delivered material at low nanomolar or low micromolar concentration levels. However, in disease conditions, abnormal tryptophan metabolism can be accompanied by changes in levels of KP metabolites.
  • 753
  • 17 Nov 2021
Topic Review
Metal-Organic-Frameworks: Low Temperature Gas Sensing
Metal-organic frameworks (MOFs), a class of porous coordination polymers (PCPs), are crystalline frameworks with open porosity and are composed of metal nodes and organic linkers. Over the last two decades, numerous compounds have been synthesised by changing the metal ions and organic ligands to produce materials with exceptional properties, including large surface area (surface areas more than 1,000 m2g−1), adjustable pore size, and tunable functional groups. The manifold approaches for MOF synthesis, including the most versatile and widely used solvothermal methods, and recently realised green approaches, such as solvent-free mechanochemical routes, are making the process of preparing high-quality MOF-based materials easier and more environmentally friendly.
  • 753
  • 30 Nov 2021
Topic Review
Hypercrosslinking of Poly(vinylbenzyl chloride) PolyHIPEs
The concept of polymer chain hypercrosslinking was introduced by Davankov, Rogoshin and Tsyurupa, using linear polystyrene or swollen gel-type poly (styrene-co-divinylbenzene) in the presence of an external crosslinker, solvent and a Lewis base as a catalyst.
  • 753
  • 30 Aug 2021
Topic Review
Perfluoropyridine
The fluorine atom exhibits many unique properties, including a small atomic radius, large electronegativity, and minimal polarizability. Thus, when coupled with carbon in the form of a C-F bond, organofluorine compounds with highly sought after properties can be obtained. Perfluoropyridine (PFPy) is an organofluorine compound that has been employed for a variety of applications, from straightforward chemical synthesis to more advanced functions, such as fluorinated networks and polymers. This can be directly attributed to the highly reactive nature of PFPy, especially towards nucleophilic aromatic substitution (SNAr).
  • 753
  • 10 Mar 2022
Topic Review
Polymer-Matrix Composites - Environmental Fatigue, Creep, Long-Term Durability
Polymer-matrix composites are widely used in engineering applications. Yet, environmental factors impact their macroscale fatigue and creep performances significantly, owing to several mechanisms acting at the microstructure level. Seawater, due to a combination of high salinity and pressures, low temperature and biotic media present, also contributes to the acceleration of fatigue and creep damage. Similarly, other liquid corrosive agents penetrate into cracks induced by cyclic loading and cause dissolution of the resin and breakage of interfacial bonds. UV radiation either increases the crosslinking density or scissions chains, embrittling the surface layer of a given matrix. Temperature cycles close to the glass transition damage the fibre–matrix interface, promoting microcracking and hindering fatigue and creep performance. The microbial and enzymatic degradation of biopolymers is also studied, with the former responsible for metabolising specific matrices and changing their microstructure and/or chemical composition. 
  • 753
  • 07 Jul 2023
Topic Review
Silicon Integrated Photonics Technologies for Sensing Applications
Silicon (Si) photonics has emerged as one of the most viable technical platforms for manufacturing a range of functional optical components because of the fast advances in technology over the last decade. Si photonics exploration and deployment have accelerated in previous years, as both photonic component performance and photonic integration complexity have been greatly enhanced and increased. It assists a variety of applications, involving datacom and telecom, as well as sensors, such as light detection and ranging (LIDAR), gyroscopes, biosensors, and spectrometers.
  • 753
  • 20 May 2022
Topic Review
Hard Carbons as Anodes in Sodium-Ion Batteries
Sodium-ion batteries (SIBs) are regarded as promising alternatives to lithium-ion batteries (LIBs) in the field of energy, especially in large-scale energy storage systems. Tremendous effort has been put into the electrode research of SIBs, and hard carbon (HC) stands out among the anode materials due to its advantages in cost, resource, industrial processes, and safety. However, different from the application of graphite in LIBs, HC, as a disordered carbon material, leaves more to be completely comprehended about its sodium storage mechanism, and there is still plenty of room for improvement in its capacity, rate performance and cycling performance.
  • 753
  • 21 Oct 2022
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