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Topic Review
Additive Manufacturing (AM)
AM is one technique which can be used to enhance the heat transfer rates of heat-exchanging devices and preserve the large sums of energy that are wasted from generated entropy and exergy.
  • 990
  • 22 Jan 2021
Topic Review
Metals in Medicine
Metals in medicine are used in organic systems for diagnostic and treatment purposes. Inorganic elements are also essential for organic life as cofactors in enzymes called metalloproteins. When metals are scarce or high quantities, equilibrium is set out of balance and must be returned to its natural state via interventional and natural methods.
  • 983
  • 31 Oct 2022
Topic Review
Fluorescence Enhancement without Structural Modifications
The Green Fluorescent Protein (GFP) and its analogues have been widely used as fluorescent biomarkers in cell biology. Yet, the chromophore responsible for the fluorescence of the GFP is not emissive when isolated in solution, outside the protein environment. Many efforts have been devoted to the study of this famiy of fluorophores, especially on the ways to restaure their emission intensity without modifying their backbone. Here are presented several ways to enhance the emission intensity of these fluorophores, modifying their environment but not their structure.
  • 983
  • 13 Jan 2023
Topic Review
Integration of CO2 Capture and Utilization
Integrated CO2 capture and utilization aims to capture CO2 from gas streams and other emission sources and convert it into valuable chemicals or energy sources. The key is to find the match between the CO2 separation process and the CO2 utilization process, including the temperature and pressure, etc. CO2 can be captured via physical or chemical absorption depending on the interaction between CO2 and the absorbent. 
  • 979
  • 07 Jun 2023
Topic Review
Cr(VI) in Contaminated Coastal Groundwater
Chromium concentrations in seawater are less than 0.5 μg/L, but the Cr(VI) in contaminated coastal groundwater affected by Cr-bearing rocks/ores and/or human activities, coupled with the intrusion of seawater may reach values of hundreds of μg/L. A potential explanation for the sta-bility of the harmful Cr(VI) in contaminated coastal aquifers is still unexplored.
  • 975
  • 01 Mar 2021
Topic Review
Isopropyl Cyanide
Isopropyl cyanide is a complex organic molecule that has been recently found in several meteorites arrived from space. The singularity of this chemical is due to the fact that it is the only one among the molecules arriving from the universe that has a branched, rather than straight, carbon backbone which is larger than usual, in comparison with others.
  • 969
  • 18 Nov 2022
Topic Review
Photoactive Heterostructures
In this study we consider the results on the development and exploration of heterostructured photoactive materials with major attention focused on what are the better ways to form this type of materials and how to explore them correctly. Regardless of what type of heterostructure, metal–semiconductor or semiconductor–semiconductor, is formed, its functionality strongly depends on the quality of heterojunction. In turn, it depends on the selection of the heterostructure components (their chemical and physical properties) and on the proper choice of the synthesis method. Several examples of the different approaches such as in situ and ex situ, bottom-up and top-down, are reviewed. At the same time, even if the synthesis of heterostructured photoactive materials seems to be successful, strong experimental physical evidence demonstrating true heterojunction formation are required. A possibility for obtaining such evidence using different physical techniques is discussed.
  • 936
  • 24 Mar 2021
Topic Review
Overcoming Defects in Wide Bandgap Semiconductor Power Electronics
Crystal defects play roles in wide bandgap semiconductors and dielectrics under extreme environments (high temperature, high electric and magnetic fields, intense radiation, and mechanical stresses) found in power electronics. Defects requires real-time in situ material characterization during material synthesis and when the material is subjected to extreme environmental stress. It is shown that the reduction of defects represents a fundamental breakthrough that will enable wide bandgap (WBG) semiconductors to reach full potential. High-brightness X-rays from synchrotron sources and advanced electron microscopy techniques are used for atomic-level material probing to understand and optimize the genesis and movement of crystal defects during material synthesis and extreme environmental stress.
  • 921
  • 11 Jan 2022
Topic Review
Dynamic Nuclear Polarisation
Dynamic nuclear polarization (DNP) results from transferring spin polarization from electrons to nuclei, thereby aligning the nuclear spins to the extent that electron spins are aligned. Note that the alignment of electron spins at a given magnetic field and temperature is described by the Boltzmann distribution under the thermal equilibrium. It is also possible that those electrons are aligned to a higher degree of order by other preparations of electron spin order such as: chemical reactions (leading to Chemical-Induced DNP, CIDNP), optical pumping and spin injection. DNP is considered one of several techniques for hyperpolarization. DNP can also be induced using unpaired electrons produced by radiation damage in solids. When electron spin polarization deviates from its thermal equilibrium value, polarization transfers between electrons and nuclei can occur spontaneously through electron-nuclear cross relaxation and/or spin-state mixing among electrons and nuclei. For example, the polarization transfer is spontaneous after a homolysis chemical reaction. On the other hand, when the electron spin system is in a thermal equilibrium, the polarization transfer requires continuous microwave irradiation at a frequency close to the corresponding electron paramagnetic resonance (EPR) frequency. In particular, mechanisms for the microwave-driven DNP processes are categorized into the Overhauser effect (OE), the solid-effect (SE), the cross-effect (CE) and thermal-mixing (TM). The first DNP experiments were performed in the early 1950s at low magnetic fields but until recently the technique was of limited applicability for high-frequency, high-field NMR spectroscopy, because of the lack of microwave (or terahertz) sources operating at the appropriate frequency. Today such sources are available as turn-key instruments, making DNP a valuable and indispensable method especially in the field of structure determination by high-resolution solid-state NMR spectroscopy.
  • 918
  • 22 Nov 2022
Topic Review
Cryogenic-Mechanical Properties of Amorphous Alloys
Research on the mechanical properties of bulk-amorphous alloys at low temperatures has mostly focused on tension and compression studies and there are relatively few studies on their low-temperature impact properties. In order to expand the application of bulk amorphous alloys in low-temperature extreme environments, it is necessary to continue to explore other properties of bulk-amorphous alloys and to reveal the response mechanism of their microstructures and properties at low temperatures.
  • 912
  • 12 Dec 2022
Topic Review
Atomically Dispersed Catalytic Sites for Photocatalytic Water Splitting
SAPCs provide a new pathway for the construction of high performance cocatalyst/photocatalyst composites. For the past few years, the preparation method, characterization technology, theoretical modeling, and mechanism investigation of SAPCs have been developed rapidly, promoting the rational design and fabrication of more efficient SAPCs. As discussed above, benefitting from their low-coordination status, unique electric structures, and metal-support interactions, SAPCs can bring about unique advantages in comparison with the nanocluster-based, nanoparticle-based, and bulk catalysts.
  • 911
  • 15 Nov 2021
Topic Review
Inorganic Compounds by Element
This is a list of common inorganic and organometallic compounds of each element. Compounds are listed alphabetically by their chemical element name rather than by symbol, as in list of inorganic compounds.
  • 901
  • 09 Oct 2022
Topic Review
Characteristics of Fresh UHPFRC
Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. 
  • 890
  • 05 Aug 2021
Topic Review
Enhancing the Health-Promoting Effect of Dietary Fiber
Fruit and vegetable by-products are rich in dietary fiber (DF), which consists of plant carbohydrate polymers. These polymers encompass oligo- and polysaccharides (e.g., cellulose, pectin, hemicellulose, resistant starch, lignin), often linked with non-carbohydrate compounds, and are not digestible or absorbable in the small intestine. DF is composed of a major insoluble part (IDF), primarily cellulose but also lignin, and a water-soluble fraction (SDF), comprised of some hemicellulosic but mainly pectic substances. 
  • 887
  • 19 Oct 2023
Topic Review
Evolution of the Vitamin D Receptor
The evolution of the vitamin D receptor started millions of years ago, with earliest evidence of the receptor in existing organisms tracing back to the sea lamprey (Petromyzon marinus). The vitamin D receptor is an example of a nuclear receptor, which binds vitamin D, and modulates the transcription of various target genes appropriately. Early in the history of life on Earth, nuclear receptors would have been selected for due to the strong pressure for organisms to respond to their environment. This eventually lead to the evolution of nuclear receptor families, such as the NR1H and NR1I families, capable of binding nutritional ligands and modulating transcription appropriately. Each of these families host a variety of receptors, including the vitamin D receptor, but all are thought to have originated from one ancestral receptor. Through major gene duplications and variable selective pressures, the various receptors within these families evolved, each one accommodating cholesterol derivatives, such as oxysterols, bile acids, and vitamin D.
  • 881
  • 21 Nov 2022
Topic Review
Characterise Lignin in Archaeological Wood
With comparison to cellulose and hemicelluloses, lignin is generally less prone to most degradation processes affecting archaeological artefacts in burial environments, especially waterlogged ones, which are the most favourable for wood preservation. Nevertheless, lignin also undergoes significant chemical changes. As wood from waterlogged environments is mainly composed of lignin, knowledge of its chemical structure and degradation pathways is fundamental for choosing preventive conservation conditions and for optimising consolidation methods and materials, which directly interact with the residual lignin. Analytical pyrolysis coupled with mass spectrometry, used in several complementary operational modes, can gather information regarding the chemical modifications and the state of preservation of lignin, especially concerning oxidation and depolymerisation phenomena. Several applications to the analysis of wood from archaeological artefacts affected by different conservation problems are presented to showcase the potential of analytical pyrolysis in various scenarios that can be encountered when investigating archaeological waterlogged wood.
  • 878
  • 11 Jan 2021
Topic Review
Recycled Silicon and Silicon-Based Thermoelectrics for Power Generation
Silicon is the second most earth-abundant element in the earth’s crust, and the most abundant element used in modern-day technologies. Its popularity partially stems from the nontoxic and relatively unreactive nature of derivatives, such as silica and silicates, at room temperature. Consequently, the sheer volume of silicon being used has accelerated the rate of production of waste materials.
  • 875
  • 11 Mar 2022
Topic Review
William Freer Bale
William Freer Bale (1911 – 28 June 1982), biophysicist and educator, held key positions in the Atomic Energy Project at the University of Rochester. Pioneer in the study of radon exposure to miners.
  • 868
  • 10 Oct 2022
Topic Review
Materials for treating burns
This article explains this product's requirements and reviews the developmental steps and published literature on the use of Suprathel® (Polymedics Innovations GmbH.  Denkendorf, Germany). Successful research and development cooperation between a textile research institute, the German Federal Ministry of Education and Research via the Center for Biomaterials and Organ Substitutes, the University of Tübingen, and the Burn Center of Marienhospital, Stuttgart, Germany, led to the development of a fully synthetic resorbable temporary epidermal skin substitute for the treatment of burns, burn-like syndromes, donor areas, and chronic wounds. This article describes the demands of the product and the steps that were taken to meet these requirements. The material choice was based on the degradation and full resorption of polylactides to lactic acid and its salts. The structure and morphology of the physical, biological, and degradation properties were selected to increase the angiogenetic abilities, fibroblasts, and extracellular matrix generation. Water vapor permeability and plasticity were adapted for clinical use. The available scientific literature was screened for the use of this product. A clinical application demonstrated pain relief paired with a reduced workload, fast wound healing with a low infection rate, and good cosmetic results. A better understanding of the product’s degradation process explained the reduction in systemic oxidative stress shown in clinical investigations compared to other dressings, positively affecting wound healing time and reducing the total area requiring skin grafts.
  • 860
  • 23 Feb 2021
Topic Review
Sanguinones
Mycena sanguinolenta, commonly known as the bleeding bonnet, the smaller bleeding Mycena, or the terrestrial bleeding Mycena, is a species of mushroom in the family Mycenaceae. It is a common and widely distributed species, and has been found in North America, Europe, Australia, and Asia. The fungus produces reddish-brown to reddish-purple fruit bodies with conic to bell-shaped caps up to 1.5 cm (0.6 in) wide held by slender stipes up to 6 cm (2.4 in) high. When fresh, the fruit bodies will "bleed" a dark reddish-purple sap. The similar Mycena haematopus is larger, and grows on decaying wood, usually in clumps. M. sanguinolenta contains alkaloid pigments that are unique to the species, may produce an antifungal compound, and is bioluminescent. The edibility of the mushroom has not been determined.
  • 851
  • 16 Nov 2022
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