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Topic Review
Torsion-Resistant Nature-Inspired Structures
The complexity of torsional load, its three-dimensional nature, its combination with other stresses, and its disruptive impact make torsional failure prevention an ambitious goal. However, even if the problem has been addressed for decades, a deep and organized treatment is still lacking in the actual research landscape. For this reason, this review aims at presenting a methodical approach to address torsional issues starting from a punctual problem definition. Accidents and breaks due to torsion, which often occur in different engineering fields such as mechanical, biomedical, and civil industry are considered and critically compared. More in depth, the limitations of common-designed torsion-resistant structures (i.e., high complexity and increased weight) are highlighted, and emerge as a crucial point for a deeper nature-driven analysis of novel solutions. In this context, an accurate screening of torsion-resistant bio-inspired unit cells is presented, taking inspiration specifically from plants, that are often subjected to the torsional effect of winds. As future insights, the actual state of technology suggests an innovative transposition to the industry: these unit cells could be prominently implied to develop novel metamaterials that could be able to address the torsional issue with a multi-scale and tailored arrangement.
  • 1.3K
  • 09 Oct 2021
Topic Review
Hydrogen Bond
The hydrogen bond may be treated as a local stabilizing interaction that acts between the proton or the electron charge deficient region of hydrogen centre and the electron rich region that is related to one or more centres. This may be named as the two-sites hydrogen bond definition. However in numerous studies the A-H proton donating bond with the positively charged H-atom and the proton acceptor, say B, being the electron rich centre are taken into account. Thus so-called A-H∙∙∙B hydrogen bridges are often considered. In such a way the three-sites hydrogen bond definition may be proposed that the hydrogen bond is the A-H∙∙∙B local stabilizing system with the proton situated between two A and B electron rich sites, most often closer to one of them, forming the A-H covalent bond; both A and B may correspond to one or more atomic centres.
  • 1.3K
  • 07 Sep 2021
Topic Review
Phage Applications against Biofilms
Biofilms are clusters of bacteria that live in association with surfaces, attached to other bacterial cells and to the surface by an extracellular polymeric matrix. Biofilms are capable of adhering to a wide variety of surfaces, both biotic and abiotic, including human tissues, medical devices, and other materials, representing a major threat causing infectious diseases and economic losses. Unfortunately, current antibiotics and common disinfectants have shown limited ability to remove biofilms adequately. Here, phage-based treatments are proposed as promising alternatives for biofilm eradication, including phage therapy, phage-derived enzymes, genetically modified phages, and phages in combination with antibiotics.
  • 1.3K
  • 05 Nov 2020
Topic Review
Polymeric Nanoparticles for Drug Delivery
The complexity of some diseases—as well as the inherent toxicity of certain drugs—has led to an increasing interest in the development and optimization of drug-delivery systems. Polymeric nanoparticles stand out as a key tool to improve drug bioavailability or specific delivery at the site of action. The versatility of polymers makes them potentially ideal for fulfilling the requirements of each particular drug-delivery system. In this review, a summary of the state-of-the-art panorama of polymeric nanoparticles as drug-delivery systems has been conducted, focusing mainly on those applications in which the corresponding disease involves an important morbidity, a considerable reduction in the life quality of patients—or even a high mortality. A revision of the use of polymeric nanoparticles for ocular drug delivery, for cancer diagnosis and treatment, as well as nutraceutical delivery, was carried out, and a short discussion about future prospects of these systems is included.
  • 1.3K
  • 27 Jul 2020
Topic Review
Reaction Mechanism of Olefins
Light olefins (C2-C4) are important C-building blocks which are currently used to produce a variety of chemicals, such as elastomers, medicines, cosmetics, detergents, solvents, etc. They can be produced by steam cracking, fluid catalytic cracking of naphtha, direct/indirect conversion of synthesis gas (CO + H2) or by hydrogenation of CO2 using H2 from renovable energy sources. However, the catalytic production of light olefins from CO2 is difficult due to the chemical inactivity of CO2 molecule, the high C-C coupling barrier and the necesity to limit the formation of C-C bond and methane. Therefore, the catalysts required for this reaction must to be multifunctional and have an optimized amount of active sites. 
  • 1.3K
  • 29 Nov 2021
Topic Review
Thermoelectric Generators at Low Operating-Temperatures
Thermoelectric generators (TEGs) are a form of energy harvester and eco-friendly power generation system that directly transform thermal energy into electrical energy. The thermoelectric (TE) method of energy harvesting takes advantage of the Seebeck effect, which offers a simple solution for fulfilling the power-supply demand in almost every electronics system. A high-temperature condition is commonly essential in the working mechanism of the TE device, which unfortunately limits the potential implementation of the device.
  • 1.3K
  • 01 Jul 2021
Topic Review
Curcumin: Biochemistry and Antitumoral Action
Curcumin is a pigment with a strong yellow colour found and the main active component of Curcuma longa, a perennial Zingiberaceae plant native to southwest India, but now grown across the South and Southeast Asia, especially in China and India. It is used for centuries as a spice and currently it is viewed as a nutraceutical due to the increasing number of scientific studies demonstrating its anti-oxidant, anti-inflammatory, anti-tumoral and cancer preventive properties. Its chemical structure comprises two aromatic ring systems with o-methoxy phenol groups connected by a seven-carbon linker consisting of an α,β-unsaturated β-diketone with tautomerism when in solution.
  • 1.3K
  • 07 Feb 2021
Topic Review
Antimicrobial Activity of Calixarenes/Related Macrocycles
Calixarenes have been shown to have antimicrobial effects since the 1950s. These properties are exemplified through their applications as prodrugs, drug delivery agents and biofilm inhibitors. A particularly important development in recent years has been their ability to engage in multivalent interactions with proteins, thus inhibiting cellular aggregation.
  • 1.3K
  • 12 Dec 2020
Topic Review
Oral Mucosal Epithelial Cells
The corneal surface is an essential organ necessary for vision, and its clarity must be maintained. The corneal epithelium is renewed by limbal stem cells, located in the limbus and in palisades of Vogt. Palisades of Vogt maintain the clearness of the corneal epithelium by blocking the growth of conjunctival epithelium and the invasion of blood vessels over the cornea. The limbal region can be damaged by chemical burns, physical damage (e.g., by contact lenses), congenital disease, chronic inflammation, or limbal surgeries. The degree of limbus damage is associated with the degree of limbal stem cells deficiency (partial or total). For a long time, the only treatment to restore vision was grafting part of the healthy cornea from the other eye of the patient or by transplanting a cornea from cadavers. The regenerative medicine and stem cell therapies have been applied to restore normal vision using different methodologies. The source of stem cells varies from embryonic stem cells, mesenchymal stem cells, to induced pluripotent stem cells. This review focuses on the use of oral mucosa epithelial stem cells and their use in engineering cell sheets to treat limbal stem cell deficient patients.
  • 1.3K
  • 30 Oct 2020
Topic Review
Magnetorheological Elastomers
Magnetorheological elastomers (MREs) are magneto-sensitive smart materials, widely used in various applications, i.e., construction, automotive, electrics, electronics, medical, minimally invasive surgery, and robotics. Such a wide field of applications is due to their superior properties, including morphological, dynamic mechanical, magnetorheological, thermal, friction and wear, and complex torsional properties.
  • 1.3K
  • 28 Dec 2020
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