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Related Concept Videos

Radical Autoxidation01:20

Radical Autoxidation

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The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
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Radical Reactivity: Steric Effects01:10

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The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic...
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Radical Reactivity: Overview01:11

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Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired...
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Radial System Protection01:23

Radial System Protection

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Radial systems employ time-delay overcurrent relays to reduce load interruptions. When a fault occurs, the nearest breaker opens first, while upstream breakers remain closed due to longer delay settings. This approach ensures minimal disruption to the rest of the system.
In a radial system with a fault downstream of the third breaker, ideally, only the third breaker will open, isolating the fault and interrupting the load connected beyond it. The second breaker has a longer delay setting,...
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Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals01:17

Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals

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Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
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Radical Formation: Overview01:03

Radical Formation: Overview

2.5K
A bond can be broken either by heterolytic bond cleavage to form ions or homolytic bond cleavage to yield radicals. A fishhook arrow is used to represent the motion of a single electron in homolytic bond cleavage. There are two main sources from which radicals can be formed:
Radicals from spin-paired molecules:
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Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
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Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development

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PolyRad - Protection Against Free Radical Damage.

Hannah Kim1, Yin Tse2, Andrew Webb2

  • 1Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO, 65409, USA.

Scientific Reports
|May 21, 2020
PubMed
Summary
This summary is machine-generated.

This study developed PolyRad, a novel nanoparticle formulation to protect melatonin from radiation damage in space. PolyRad effectively preserved melatonin

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Area of Science:

  • Materials Science
  • Pharmaceutical Sciences
  • Space Medicine

Background:

  • Elevated radiation levels in space destabilize pharmaceutical formulations, reducing drug efficacy.
  • Current technologies are insufficient for maintaining drug stability and therapeutic effectiveness in space environments.
  • There is a critical need for advanced, space-resilient drug delivery systems.

Purpose of the Study:

  • To develop a novel nanoparticle formulation, PolyRad, for protecting pharmaceutical drugs from radiation-induced degradation.
  • To enhance the stability and preserve the structural integrity and potency of melatonin, a sleep aid, for space missions.
  • To evaluate the protective efficacy of PolyRad against UV, hydrogen peroxide, and gamma radiation.

Main Methods:

  • Synthesized Melatonin-PLGA-PLL-Trolox nanoparticles (PolyRad) using a single emulsion solvent evaporation method.
  • Characterized PolyRad for size, shape, and polydispersity.
  • Exposed PolyRad and free melatonin to UV light, hydrogen peroxide, and gamma radiation (0-10 Gy); assessed melatonin structural integrity and drug release kinetics in vitro using HUVEC cells and cytotoxicity assays (Live/Dead, MTT).

Main Results:

  • PolyRad nanoparticles are spherical with an average diameter of ~600 nm and low polydispersity.
  • Bare melatonin lost ~80% of its structure after UV or H2O2 treatment, while PolyRad protected >80% of encapsulated melatonin.
  • Gamma irradiation (>98% protection) and in vitro studies showed PolyRad effectively maintained melatonin's active structure and demonstrated controlled drug release, with irradiated PolyRad showing slightly enhanced release.

Conclusions:

  • The developed PolyRad nanoparticle formulation significantly protects melatonin from radiation and oxidative damage.
  • PolyRad demonstrates a promising platform for preserving the stability and efficacy of pharmaceutical drugs in space.
  • This formulation could be crucial for enabling long-duration space missions by ensuring astronaut medication reliability.