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Topic Review
Food Science's Chemical Element Compositions
In recent years, many analyses have been carried out to investigate the chemical components of food data. However, studies rarely consider the compositional pitfalls of such analyses. This is problematic as it may lead to arbitrary results when non-compositional statistical analysis is applied to compositional datasets. In this study, compositional data analysis (CoDa), which is widely used in other research fields, is compared with classical statistical analysis to demonstrate how the results vary depending on the approach and to show the best possible statistical analysis. For example, honey and saffron are highly susceptible to adulteration and imitation, so the determination of their chemical elements requires the best possible statistical analysis. Our study demonstrated how principle component analysis (PCA) and classification results are influenced by the pre-processing steps conducted on the raw data, and the replacement strategies for missing values and non-detects. Furthermore, it demonstrated the differences in results when compositional and non-compositional methods were applied. Our results suggested that the outcome of the log-ratio analysis provided better separation between the pure and adulterated data and allowed for easier interpretability of the results and a higher accuracy of classification. Similarly, it showed that classification with artificial neural networks (ANNs) works poorly if the CoDa pre-processing steps are left out. From these results, we advise the application of CoDa methods for analyses of the chemical elements of food and for the characterization and authentication of food products.
  • 994
  • 24 Nov 2021
Topic Review
SAM-Based Electrodes
Self-assembled molecular monolayers (SAMs) are long recognized as crucial "bridges" between redox enzymes and solid electrode surfaces, on which the enzymes undergo direct electron transfer (DET)—for example, in enzymatic biofuel cells (EBFCs) and biosensors. SAMs possess a wide range of terminal groups that enable productive enzyme adsorption and fine-tuning in favorable orientations on the electrode. The tunneling distance, the SAM chain length, and the contacting terminal SAM groups are the most significant factors in SAM-controlled DET-type bioelectrocatalysis.
  • 993
  • 08 Feb 2021
Topic Review
Anticancer effects of Coumarin Sulfonamides
Coumarin is an important six-membered aromatic heterocyclic pharmacophore, widely distributed in natural products and synthetic molecules. The versatile and unique features of coumarin nucleus, in combination with privileged sulfonamide moiety, have enhanced the broad spectrum of biological activities. The research and development of coumarin, sulfonamide-based pharmacology, and medicinal chemistry have become active topics, and attracted the attention of medicinal chemists, pharmacists, and synthetic chemists. Coumarin sulfonamide compounds and analogs as clinical drugs have been used to cure various diseases with high therapeutic potency, which have shown their enormous development value. The diversified and wide array of biological activities such as anticancer, antibacterial, anti-fungal, antioxidant and anti-viral, etc. were displayed by diversified coumarin sulfonamides.
  • 993
  • 22 Mar 2022
Topic Review
Conversion of Carbon Dioxide into Methanol
As an energy source, methanol presents the advantage of being liquid at environmental temperature, which makes it easier to transport and store.
  • 993
  • 21 Apr 2022
Topic Review
Natural Thermal Convection of Nanofluids
Nanofluids are considered as advanced heat transfer media for thermal management and conversion systems. Research on the convective heat transfer is of paramount importance for their numerous applications. This paper presents development of experimental research on the natural convection heat transfer of nanofluids in different geometries. Experimental results and available experiment-derived correlations for the natural thermal convection of nanofluids are critically analysed. Other features such as nanofluid preparation and thermophysical properties of nanofluids that are important for convection heat transfer are also briefly reviewed and discussed. It is demonstrated that there is considerable inconsistencies of available results on these properties and features of nanofluids.Although nanofluids exhibit enhanced thermophysical properties like viscosity and thermal conductivity, convective heat transfer coefficients were also observed to deteriorate in some cases when nanofluids were used, especially for higher concentration of nanoparticles (> 0.1 vol%). However, the underlying mechanisms are also not yet well-understood despite its great importance for practical applications.
  • 992
  • 05 Oct 2020
Topic Review
Applications of High Performance Liquid Chromatography with Fluorescence
Steroids are compounds widely available in nature and synthesized for therapeutic and medical purposes. Steroids can be found in various environmental samples, including water, plant, and animal samples as well as in a variety of pharmaceutical forms. Due its sensitivity and selectivity, high performance liquid chromatography with fluorescence detection (HPLC-FLD) is widely used for detection of steroids in pharmaceutical and environmental samples.
  • 992
  • 11 Apr 2022
Topic Review
Polyester-Based Coatings for Corrosion Protection
Polyesters are synthetic resins formed by an esterification chemical reaction with some occurring naturally. In addition, there are different orientations of polyesters and, hence, different classifications. The classifications aid in determining the processing, curing kinetics, and overall applications of the resin. Saturated, unsaturated polyesters (UPs) and alkyd resins are the main classifications of polyesters; however, vinyl esters are also classified as polyesters since they have a di-ester group. Vinyl esters are based on the combination of an epoxy resin with an unsaturated polymer; they have excellent properties when compared to saturated, unsaturated-type polyesters and alkyd resins. Developments of non-toxic polyester-based coatings have the potential to address a wide range of pollution problems, such as air pollution and water pollution, generated during the production of conventional polyester coatings. The anticorrosion properties of polyester resin modified by nanocomposites intended for steel are of interest. The goal is to produce a bio-based polyester coating with minimal cost by implementing natural products as well as modifying with nanomaterials. 
  • 992
  • 04 Nov 2022
Topic Review
Metamaterials for Device Applications
Metamaterials are the major type of artificially engineered materials which exhibit naturally unobtainable properties according to how their microarchitectures are engineered. Owing to their unique and controllable effective properties, including electric permittivity and magnetic permeability, the metamaterials play a vital role in the development of meta-devices.
  • 991
  • 12 May 2021
Topic Review
Electrospun Nanofiber-Based Membranes for Water Treatment
Electrospun nanofiber-based membranes (ENMs), benefitting from characteristics such as a higher specific surface area, higher porosity, lower thickness, and possession of attracted broad attention, has allowed it to evolve into a promising candidate rapidly. According to the roles of electrospun nanofiber layers, NMs can be divided into two categories: (i) nanofiber layer serving as a selective layer, (ii) nanofiber layer serving as supporting substrate.
  • 991
  • 19 Sep 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
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