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Topic Review
Role of Naturally Occurring Coumarins in Plants
Coumarins are secondary plant metabolites widely distributed in higher plants, bacteria, fungi, and sponges. This great structural diversity of these natural compounds and their synthesized derivatives enables their wide range of pharmacological activities, such as antioxidant; antibacterial; antifungal; anti-human immunodeficiency infection; anti-tubercular; and anti-cancer activities. There are also many reports about their effectiveness against plant pathogenic pests (phytopathogenic fungi, bacteria, nematodes, and insects). 
  • 930
  • 08 Jun 2023
Topic Review
SBA-15 synthesis variables
SBA-15 synthetized at different values of time and temperature of the hydrothermal treatment were mixture with tobacco in order to determine the capacity of reduction of toxic and carcirogenic compounds on tobacco smoke. The effect of temperature is not significative but time presents a remarked effect. And a parameter not frequently studied, the aparent density, has been shown the most relevant relation with the results on smoking experimentos. Finally, the effect of reduce the supernatant liquor also has been studied and the results have shown that the material properties remain practically unchanged.
  • 930
  • 01 Nov 2020
Topic Review
Trends in Cu-Catalyzed Ar-Xs Transformations with Amines
Aromatic compounds (Ar-Xs) are technologically important inert low-cost solvents (chlorobenzene or o-dichlorobenzene) and intermediates for the manufacture of flame-retardant polymers used in electronics and furniture. Furthermore, Ar-Xs are the chemicals necessary for the production of industrially important dyes, pigments, and a broad group of biologically active species such as pesticides and drugs. Utilization of Ar-Xs as arylating agents based on Cu-catalyzed substitution of bound halogen (X) applying different nucleophiles serves as the technique for production of a broad scale of useful chemicals.
  • 919
  • 16 Sep 2022
Topic Review
Historical Perspective on Membrane Science and Technology
Over the last few decades, considerable effort has been devoted to developing better membranes and extending their range of applications to different areas. Membrane processes already have an established role in gas separation and water treatment, and their applications in the food, pharmaceutical, and health areas have been continuously increasing. In the last few years, membrane processes proved to have a key role in biorefinery and bioenergy production processes, namely for process intensification and the recovery and purification of valuable products. Membranes are also a crucial component of electrochemical energy conversion devices, including fuel cells and electrolysers. Moreover, the growing environmental concerns have drawn attention to the use of fossil-based polymers and toxic solvents for membrane fabrication. Therefore, the development of new membranes, using polymers from renewable sources and more sustainable fabrication methods, is being pursued.
  • 913
  • 23 Feb 2022
Topic Review
Biodiesel as Renewable Biofuel in Current Diesel Engines
Many countries are immersed in several strategies to reduce the carbon dioxide (CO2) emissions of internal combustion engines. One option is the substitution of these engines by electric and/or hydrogen engines. However, apart from the strategic and logistical difficulties associated with this change, the application of electric or hydrogen engines in heavy transport, e.g., trucks, shipping, and aircrafts, also presents technological difficulties in the short-medium term. In addition, the replacement of the current car fleet will take decades. This is why the use of biofuels is presented as the only viable alternative to diminishing CO2 emissions in the very near future. Nowadays, it is assumed that vegetable oils will be the main raw material for replacing fossil fuels in diesel engines.
  • 908
  • 13 May 2022
Topic Review
Transition Metal Oxide Electrode Materials
The rising use of nonrenewable fossil fuels in recent decades has put human existence in grave danger. As a result, it is imperative to design environmentally friendly and cost-effective energy storage devices. Supercapacitors are a promising energy device because of their high power density, outstanding cycle stability, and quick charge/discharge process. However, supercapacitors' energy density is still lower than that of conventional batteries'. Supercapacitors' electrochemical performance is heavily influenced by the electrode materials, as is well-known to everyone.
  • 907
  • 19 Apr 2022
Topic Review
Cellulose Alcoholysis to Alkyl-levulinate Biofuels
Alkyl levulinates (ALs) represent outstanding bio-fuels and strategic bio-products within the context of the marketing of levulinic acid derivatives. In order to promote the market for these bio-products and, concurrently, the immediate development of new applications, it is necessary to speed up the intensification of their production processes. In this regard, today, it is possible to achieve this important issue only by using low-cost or, even better, waste biomasses, as starting feedstocks. Thus, the transition to the real biomass now represents a necessary choice for allowing the next ALs production on a larger scale. The improvement of the available synthetic strategies, the use of raw materials and the development of new applications for ALs can contribute to develop more intensified, greener and sustainable processes. 
  • 904
  • 16 Dec 2020
Topic Review
BODIPY-Based Molecules for Organic PhotoVoltaics
The 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based molecules have emerged as interesting material for optoelectronic applications. This type of structure is commonly described as an example of a “rigidified” monomethine cyanine dye or as a boradiazaindacene by analogy with the all-carbon tricyclic ring and the numbering of any substituents follows rule setup for the carbon polycycles (see COVER). This dye has also been  called “porphyrin’s little sister” and this happy definition has been so successful that in analogy with porphyrinic systems, the 8-position is often referred to as the meso site. The facile structural modification of BODIPY core provides an opportunity to fine-tune its photophysical and optoelectronic properties thanks to the presence of eight reactive sites which allows for the developing of a large number of functionalized derivatives for various applications. In particular, BODIPY dyes find increasing application in laser dyes, organic electronic (OLED and OPV), bioimmagining,  thanks to their properties  like high fluorescent quantum yield, sharp absorption and emission peak,  photostability and stability under physiological conditions. Because of this they can be used also  as probes for pH changes, detection of cations, anions and so on.
  • 902
  • 01 Feb 2021
Topic Review
Kaolinitic Raw Materials for Ceramics
Eight kaolinitic materials from the Lokoundje River at Kribi were sampled and investigated for their physical, chemical, mineralogical and thermal characteristics in order to evaluate their potential suitability as raw materials in ceramics. The Lokoundje kaolinitic materials are clayey to silty clayey and are predominantly composed of kaolinite and quartz. The alkali (Na2O + K2O) content ranges between 1 and 2.5 wt.%; these low values do not favor vitrification of the ceramics but may be improved through flux amendment. The presence of goethite in some samples limits their utilization in white ceramics. The minerals content, color, metallic sound, cohesion, linear shrinkage, flexural strength, bulk density, water absorption and microstructure were determined. The XRD data reveal that kaolinite and goethite were transformed, respectively, into mullite and hematite. The colors of the fired products are characteristic of their mineral assemblage. The metallic sound is indicative of low vitrification which is confirmed by the presence of cracks due to low flux contents. The cohesion is good to very good, due to the abundance of kaolinite. The physicomechanical properties increase with temperature as well as densification. The geochemical data show that the Lokoundje alluvial clays are suitable for the manufacture of white stoneware tiles. 
  • 896
  • 09 Jul 2021
Topic Review
Applications of Biodegradable Poly Blends/Composites
Biodegradable poly(ɛ-caprolactone) (PCL) and its composites or blends have received a lot of attention in the past because of their potential applications in human life and environmental remediation. Greater efforts have been made to develop biodegradable chemical materials as adsorbents that do not pollute the environment in order to replace traditional materials. 
  • 880
  • 09 Nov 2023
Topic Review
Aptamer-Sensors for Quantification of AFB1
Aflatoxin B1 (AFB1) is one of the most frequently-found mycotoxins in contaminated food. As the content of mycotoxins is particularly low in food, the development of probes to detect AFB1 in foods with high sensitivity and selectivity is an urgent social need for the evaluation of food quality. Numerous techniques have been developed to monitor AFB1. Nevertheless, most of them require cumbersome, labor-consuming, and sophisticated instruments, which have limited their application. An aptamer is a single, short nucleic acid sequence that is capable of recognizing different targets. Owing to their unique properties, aptamers have been considered as alternatives to antibodies. Aptasensors are considered to be an emerging strategy for the quantification of aflatoxin B1 with high selectivity and sensitivity. 
  • 879
  • 19 Oct 2020
Topic Review
Reaction Mechanisms of Glycerol Hydrogenolysis to 1,2-Propylene Glycol
The development and growth of the biodiesel industry has led to a parallel market for the supply of glycerol, its main by-product. Its wide availability and relatively low cost as a raw material make glycerol a basic component for obtaining various chemical products and allows for the development of a biorefinery around biodiesel plants, through the technological integration of different production processes. Catalytic hydrogenolysis is an interesting alternative because it leads to the formation of 1,2-propylene glycol (1,2-PG) and other glycols such as 1,3-propylene glycol (1,3-PG) and ethylene glycol (EG), widely used in the chemical industry. In the following text, the main reaction mechanisms of glycerol hydrogenolysis are presented, focusing on the production of 1,2-PG, in order of chronological appearance.
  • 875
  • 10 May 2023
Topic Review
Bis-Chalcone-Based Photoinitiators of Polymerization
Over the past several decades, photopolymerization has become an active research field, and the ongoing efforts to develop new photoinitiating systems are supported by the different applications in which this polymerization technique is involved—including dentistry, 3D and 4D printing, adhesives, and laser writing.
  • 873
  • 23 Jun 2021
Topic Review
Megamolecular Polysaccharide Sacran
Natural polymer is a frequently used polymer in various food applications and pharmaceutical formulations due to its benefits and its biocompatibility compared to synthetic polymers. One of the natural polymer groups (i.e., polysaccharide) does not only function as an additive in pharmaceutical preparations, but also as an active ingredient with pharmacological effects.
  • 866
  • 21 Jun 2021
Topic Review
Molecular Sensing with Hyperpolarized 129Xe
Hyperpolarized noble gases have been used early on in applications for sensitivity enhanced NMR. 129Xe has been explored for various applications because it can be used beyond the gas-driven examination of void spaces. Its solubility in aqueous solutions and its affinity for hydrophobic binding pockets allows "functionalization" through combination with host structures that bind one or multiple gas atoms. Moreover, the transient nature of gas binding in such hosts allows the combination with another signal enhancement technique, namely chemical exchange saturation transfer (CEST). Different systems have been investigated for implementing various types of so-called Xe biosensors where the gas binds to a targeted host to address molecular markers or to sense biophysical parameters.
  • 863
  • 19 Oct 2020
Topic Review
Development Aspects for Practical Non-aqueous Redox-Flow Batteries
Redox-flow cells can be divided into four basic types: all-liquid redox-flow batteries (ALRFBs), semi-solid redox-flow batteries (SSRFBs), hybrid redox-flow batteries (HRFBs), and single-flow batteries (SFB). These four basic types can be further classified by their cell separation techniques and membrane setups. They range from having no separation membrane to having up to three separation membranes in parallel.
  • 860
  • 20 Feb 2023
Topic Review
Catalytic Activity of Zeolite
Zeolites are microporous aluminosilicates with high surface area and crystallinity. They have been widely applied in many different fields, such as gas storage, water treatment, biomass upgrading, and oil refining, because of their strong acidity, excellent catalytic activity, shape selectivity, and hydrothermal stability. In the past decades, one of the most important applications of zeolites is in fluidized catalytic cracking (FCC) in the petrochemical industry, which accounts for more than 95% of the global zeolite catalyst consumption. It is reported that 400 million tons of olefins are produced annually, and about 59% of olefins are produced by FCC units. Light olefins are critical building blocks in the petrochemical industry, and the demand for olefins and their derivatives has continuously increased over the last decade. Therefore, it is important to understand how to improve the catalytic performance of zeolites. Studies have shown that the performance of zeolite catalysts for cracking reactions is determined by various factors, including the porous size and composition, e.g., the Si/Al ratio and the presence of other heteroatoms or extra-framework aluminum (EFAL) species. Since the range of possible combinations of zeolite structures and compositions is exceedingly large, it is highly desirable to understand the effects of zeolite topology and composition on hydrocarbon cracking in order to improve their activity and selectivity to desired products.
  • 859
  • 09 Oct 2021
Topic Review
Electrostatic Repulsion Reversed-Phase Liquid Chromatography
Electrostatic Repulsion Reversed-Phase Liquid Chromatography (ERRP) allows the elution of bases in protonated form without peak distorsion (as commonly happen in reversed phase) due to the presence of positive charges in the chromatographic system. 
  • 858
  • 05 Aug 2021
Topic Review
Formulation of Marketing Strategies for Cultured Meat
Existing conventional meat production systems have negative environmental effects, coupled with growing public health concerns. Furthermore, growing population has continued to increase the consumer demand for meat. Research suggested the utilization of cultured meat (CUME) grown from animal cells without encompassing the slaughtering process. Additional benefits of CUME include being environmentally friendly, with lower production of greenhouse gases, reduced land, and water usage. Studies were conducted to determine the overall consumer acceptability of CUME. Studies have also elaborated that wide-scale adoption of CUME is dependent on a multitude of factors, including regulatory bodies, economic availability, religion, and media perception of CUME.
  • 857
  • 14 Sep 2022
Topic Review
CRM for Additive Manufacturing
The term “critical raw materials” (CRMs) refers to various metals and nonmetals that are crucial to Europe’s economic progress. Modern technologies enabling effective use and recyclability of CRMs are in critical demand for the EU industries. The use of CRMs, especially in the fields of biomedicine, aerospace, electric vehicles, and energy applications, is almost irreplaceable. Additive manufacturing (also referred to as 3D printing) is one of the key enabling technologies in the field of manufacturing which underpins the Fourth Industrial Revolution. 3D printing not only suppresses waste but also provides an efficient buy-to-fly ratio and possesses the potential to entirely change supply and distribution chains, significantly reducing costs and revolutionizing all logistics. This review provides comprehensive new insights into CRM-containing materials processed by modern additive manufacturing techniques and outlines the potential for increasing the efficiency of CRMs utilization and reducing the dependence on CRMs through wider industrial incorporation of AM and specifics of powder bed AM methods making them prime candidates for such developments.
  • 846
  • 05 May 2021
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