Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Polyurea in Impact Penetration Resistance and Blast Mitigation
Polyurea has gained significant attention in recent years as a functional polymer material, specifically regarding blast and impact protection. The molecular structure of polyurea is characterized by the rapid reaction between isocyanate and the terminal amine component, and forms an elastomeric copolymer that enhances substrate protection against blast impact and fragmentation penetration. At the nanoscale, a phase-separated microstructure emerges, with dispersed hard segment microregions within a continuous matrix of soft segments. This unique microstructure contributes to the remarkable mechanical properties of polyurea. 
  • 436
  • 11 Mar 2024
Topic Review
COF-Based Photocatalysts for Enhanced Synthesis of Hydrogen Peroxide
Photocatalytic synthesis of H2O2 has emerged as a compelling alternative, offering the prospect of harnessing solar energy directly to drive chemical reactions, thereby circumventing the need for energy-intensive processes and deleterious chemicals.
  • 131
  • 11 Mar 2024
Topic Review
Covalent Organic Frameworks for Cathode Materials
Covalent organic frameworks (COFs) are constructed from small organic molecules through reversible covalent bonds, and are therefore considered a special type of polymer. Small organic molecules are divided into nodes and connectors based on their roles in the COF’s structure. The connector generally forms reversible covalent bonds with the node through two reactive end groups. The adjustment of the length of the connector facilitates the adjustment of pore size. Due to the diversity of organic small molecules and reversible covalent bonds, COFs have formed a large family since their synthesis in 2005. Among them, a type of COF containing redox active groups such as –C=O–, –C=N–, and –N=N– has received widespread attention in the field of energy storage. The ordered crystal structure of COFs ensures the ordered arrangement and consistent size of pores, which is conducive to the formation of unobstructed ion channels, giving these COFs a high-rate performance and a long cycle life. The voltage and specific capacity jointly determine the energy density of cathode materials.
  • 93
  • 08 Mar 2024
Topic Review
Protonic Ceramic Electrolysis Cells Design for NH3 Synthesis
The application of protonic ceramic electrolysis cells (PCECs) for ammonia (NH3) synthesis has been evaluated over the past 14 years. While nitrogen (N2) is the conventional fuel on the cathode side, various fuels such as methane (CH4), hydrogen (H2), and steam (H2O) have been investigated for the oxygen evolution reaction (OER) on the anode side. Because H2 is predominantly produced through CO2-emitting methane reforming, H2O has been the conventional carbon-free option thus far. Although the potential of utilizing H2O and N2 as fuels is considerable, studies exploring this specific combination remain limited. 
  • 202
  • 07 Mar 2024
Topic Review
Development Progress of Proton Exchange Membrane Fuel Cells
Proton exchange membrane fuel cells (PEMFCs) have the potential to tackle major challenges associated with fossil fuel-sourced energy consumption. Nafion, a perfluorosulfonic acid (PFSA) membrane that has high proton conductivity and good chemical stability, is a standard proton exchange membrane (PEM) used in PEMFCs. However, PEM degradation is one of the significant issues in the long-term operation of PEMFCs. Membrane degradation can lead to a decrease in the performance and the lifespan of PEMFCs. The membrane can degrade through chemical, mechanical, and thermal pathways.
  • 179
  • 07 Mar 2024
Topic Review
Laccase
Enzymes play an important role in numerous natural processes and are increasingly being utilized as environmentally friendly substitutes and alternatives to many common catalysts. Both horseradish peroxidase (HRP) and laccase are most often utilized for the formation of enzyme aggregates due to their ability to rapidly oxidize phenols, generating phenoxy radicals which undergo radical coupling to form biphenyl or phenyl ether linkages. 
  • 369
  • 07 Mar 2024
Topic Review
Ruthenium(II)
The two Ru(III) and Ru(II) complexes, namely, BOLD-100 and RAPTA-C, are presently being studied in a clinical trial and preclinical studies evaluation, respectively, as anticancer agents. Ruthenium N-heterocyclic carbene (Ru-NHC) complexes show interesting properties in medicinal chemistry, exhibiting multiple biological activities, among them anticancer, antimicrobial, antioxidant, and anti-inflammatory. Among the newly synthesized complexes, RANHC-V and RANHC-VI are the most active against triple-negative human breast cancer cell lines MDA-MB-231. These compounds were selective in vitro inhibitors of the human topoisomerase I activity and triggered cell death by apoptosis. Furthermore, the Ru-NHC complexes’ antimicrobial activity was studied against Gram-positive and -negative bacteria, revealing that all the complexes possessed the best antibacterial activity against the Gram-positive Staphylococcus aureus, at a concentration of 0,025 mg/mL. Finally, the antioxidant effect was assessed by DPPH and ABTS radicals scavenging assays, resulting in a higher ability for inhibiting the ABTS+, with respect to the well-known antioxidant Trolox. Thus, this work provides encouraging insights for further development of novel Ru-NHC complexes as potent chemotherapeutic agents endowed with multiple biological properties.
  • 248
  • 07 Mar 2024
Topic Review
Intermediate-Temperature Embrittlement of Metals and Alloys
The intermediate-temperature embrittlement range was examined for Fe, Al, Cu, and Ni alloys. It was found that this embrittlement occurs in many alloys, although the causes are very diverse. Embrittlement can be due to fine matrix precipitation, precipitate free zones, melting of compounds at the grain boundaries, segregation of elements to the boundaries, and, additionally for steel, the presence of the soft ferrite film surrounding the harder austenite matrix. Grain boundary sliding and segregation to the boundaries seem to dominate the failure mode at the base of the trough when intergranular failure takes place. When cracking is due to the presence of hydrogen or liquid films at the boundary, then the dissociation along the boundaries is so easy, it is often independent of the strain rate and is always intergranular. 
  • 210
  • 06 Mar 2024
Topic Review
Pillar[n]arene-Based Supramolecular Polymers
The field of fluorescence sensing, leveraging various supramolecular self-assembled architectures constructed from macrocyclic pillar[n]arenes, has seen significant advancement in recent decades.
  • 142
  • 06 Mar 2024
Topic Review
Marine-Derived Bisindoles for Potent Selective Cancer Drug Discovery
Indole is a multifunctional active pharmacophore and a heterocyclic compound widely present in natural and synthetic compounds with biological activity. Indole alkaloids from natural sources display diverse mechanisms and structures and exert anticancer potential through various antiproliferation mechanisms. Thus, indole alkaloids play a significant role in the discovery of new anticancer drugs. Scientists have subsequently isolated various new bisindole alkaloids from marine organisms, especially deep-water sponges. They are usually extracted with organic solvents (e.g., methanol, ethyl acetate). And the extracts were concentrated and partitioned between organic and aqueous phases. The organic phase is separated with chromatography separation technology, including silica gel column chromatography, high-performance liquid chromatography, etc. Most marine-derived bisindoles exist in solid form, which makes it convenient for us to determine their absolute configuration by single crystal. A number of marine-derived bisindoles exhibit strong and varied biological activities. Due to their unique biological activities and chemical structures, they have become a research focal point in pharmaceutical chemistry as lead compounds for new drug development. It is noteworthy that many drugs based on marine-derived bisindoles have been approved or are currently in clinical research, such as midostaurin, lestaurtinib, and enzastaurin. These drug molecules have shown potent selective anti-tumor effects.
  • 209
  • 06 Mar 2024
  • Page
  • of
  • 467
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Video Production Service
Feedback