Photon strength functions from (p,γ) reactions Netshiya, A. A.; Wiedeking, M.; Pellegri, L. ...
Journal of physics. Conference series,
09/2023, Letnik:
2586, Številka:
1
Journal Article
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Abstract
The
50
Cr(p,
γ
)
51
Mn proton capture reaction has been used to study the photon strength functions by utilizing primary gamma ray transitions from the entry states to discrete states of ...known spins and parities. The reaction was conducted with the 3 MV Tandetron accelerator at iThemba LABS which delivered proton beams of 2.5 to 2.740, 2.760 to 3.0 MeV and 3.675 to 4.498 MeV in intervals of 20-25 keV with beam currents of up to 5
μ
A. In this work the proton capture reaction was employed together with the Average Resonance Capture method to extract the shape of the PSF of
51
Mn.
7-Azaindole has been labelled a privileged scaffold for the design of new potent inhibitors of protein kinases. In this paper, we determined the inhibition profiles of novel mono- and disubstituted ...derivatives of 7-azaindole-coumaranone hybrids on various disease-related protein kinases. Eight hit compounds were identified, including a potent Haspin inhibitor with an IC50 value of 0.15 μM. An interesting observation was that all active monosubstituted compounds displayed dual inhibition for Haspin and GSK-3β, while disubstituted derivatives inhibited GSK-3β and LmCK1 from Leishmania major parasite. Analyses of structure activity relationships (SARs) also revealed that mono-substitution with para-fluorobenzyloxy ring produced an equipotent inhibition of Haspin and GSK-3β. Haspin and GSK-3β are relevant targets for developing new anticancer agents while LmCK1 is an innovative target for leishmanicidal drugs. Novel compounds reported in this paper constitute promising starting points for the development of new anticancer and leishmanicidal drugs.
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•7-Azaindole-coumaranone hybrids were screened against eight disease-relevant protein kinases.•Six compounds demonstrated dual inhibition for Haspin and GSK-3β.•Two compounds are dual inhibitors of GSK-3β and LmCK1.•The most potent inhibitor (7h) exhibits submicromolar IC50 values for both Haspin and GSK-3β.•One compound (7b) exhibited equipotent inhibition for Haspin and GSK-3β.
Chalcones are a group of naturally occurring or synthetic compounds which possess a wide range of biological activities. In this paper, a series of twenty‐three 7‐azaindole‐chalcone hybrids (5a–w) ...were synthesized and evaluated as potential protein kinase inhibitors. Analyses of structure–activity relationships revealed that some of these compounds exhibit significant activity against Haspin kinase, with compounds 5f and 5q exhibiting IC50 values of 0.47 and 0.41 µM, respectively. Furthermore, 5f also inhibits cyclin‐dependent kinase 9 (CDK9/CyclinT) in a micromolar potency (IC50 = 2.26 µM). This novel dual‐target inhibitor is a promising lead for the development of chemopreventive/chemotherapeutic agents.
In this paper, a series of 23 7‐azaindole‐chalcone hybrids (5a–w) were synthesised and evaluated as potential protein kinase inhibitors. Analyses of structure activity relationships revealed that some of these compounds exhibit significant activity against Haspin kinase, with compounds 5f and 5q exhibiting IC50 values of 0.47 and 0.41 µM, respectively. Furthermore, 5f also inhibits cyclin‐dependent kinase 9 (CDK9/CyclinT) in a micromolar potency (IC50 = 2.26 µM). This novel dual‐target inhibitor is a promising lead for the development of chemopreventive/chemotherapeutic agents.
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In the present study, a series of fourteen 2-mercapto-4(3H)-quinazolinone derivatives was synthesised and evaluated as potential inhibitors of the human monoamine oxidase (MAO) ...enzymes. Quinazolinone is the oxidised form of quinazoline, and although this class has not yet been extensively explored as MAO inhibitors, it has been shown to possess a wide variety of biological activities. Among the quinazolinone derivatives investigated, seven compounds (IC50 < 1 µM) proved to be potent and specific MAO-B inhibitors, with the most potent inhibitor, 2-(3-iodobenzyl)thioquinazolin-4(3H)-one, exhibiting an IC50 value of 0.142 μM. Further investigation showed that this inhibitor is a reversible and competitive inhibitor of MAO-B with a Ki value of 0.068 µM. None of the test compounds were MAO-A inhibitors. Analysis of the structure-activity relationships (SARs) for MAO-B inhibition shows that substitution on the C2 position of quinazolinone with a benzylthio moiety bearing a Cl, Br or I on the meta position yields the most potent inhibitors of the series. In contrast, substitution with the unsubstituted benzylthio moiety (IC50 = 3.03 µM) resulted in significantly weaker inhibition activity towards MAO-B. This study suggests that quinazolinones are promising leads for the development of selective MAO-B inhibitors which may be used for the treatment of neurodegenerative disorders such as Parkinson’s disease.
In this report, we demonstrate the biochemical modification of silica based nanoparticles. Both pure and dye-doped silica nanoparticles were prepared, and their surfaces were modified with enzymes ...and biocompatible chemical reagents that allow them to function as biosensors and biomarkers. The nanoparticles produced in this work are uniform in size with a 1.6% relative standard deviation. They have a pure silica surface and can thus be modified easily with many biomolecules for added biochemical functionality. Specifically, we have modified the nanoparticle surfaces with enzyme molecules (glutamate dehydrogenase (GDH) and lactate dehydrogenase (LDH)) and a biocompatible reagent for cell membrane staining. Experimental results show that the silica nanoparticles are a good biocompatible solid support for enzyme immobilization. The immobilized enzyme molecules on the nanoparticle surface have shown excellent enzymatic activity in their respective enzymatic reactions. The nanoparticle surface biochemical functionalization demonstrates the feasibility of using nanoparticles for biosensing and biomarking applications.
This research work focuses on the development of a piezoelectric magnetostrictive smart composite with advanced sensing capability. The composite piezoelectric property is achieved from the ...dispersion of single-walled carbon nanotubes (SWCNTs) and the magnetostrictive property from Terfenol-D nanoparticles. Finite element analysis (FEA) is used to examine the feasibility of modelling the piezoelectric (change in electric field) and magnetostrictive (change in magnetic field) self-sensing responses in the presence of applied stress. The numerical work was coupled with a series of mechanical tests to characterize the piezoelectric response, magnetostriction response and mechanical strength. Tensile tests of the composite samples manufactured as is (virgin), samples with SWCNTs, samples with Terfenol-D nanoparticles and samples with both SWCNTs and Terfenol-D nanoparticles were conducted. It was observed that an increase in volume fraction of Terfenol-d nanoparticles increases the change in magnetization, therefore increasing voltage response up to the point of saturation. The optimum change in amplitude was observed with 0.35% volume fraction of Terfenol-D nanoparticles. A constant ratio of SWCNTs was maintained, and maximum change in electrical resistance was at 7.4%. Fracture toughness for the samples with all nanoparticles was explored, and the results showed improved resistance to crack propagation.
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•4(3H)-Quinazolinones were investigated as potential inhibitors of MAO.•Some N3/C6-disubstituted derivatives are selective MAO-B inhibitors.•The most potent MAO-B inhibitor exhibited ...a Ki value of 0.648 µM (8b).•Compound 8b is an irreversible MAO-B inhibitor.
Parkinson’s disease is characterised by the death of the nigrostriatal neurons and depletion of striatal dopamine. The standard symptomatic therapy consists of dopamine replacement with l-dopa, the metabolic precursor of dopamine, which represents the most effective treatment. Since monoamine oxidase (MAO) B is a key dopamine metabolising enzyme in the brain, MAO-B inhibitors are often used as adjuvants to l-dopa. In addition to the symptomatic benefits offered by MAO-B inhibitors, these drugs may also possess neuroprotective properties and possibly delay the progression of Parkinson’s disease. Based on the therapeutic use of MAO-B inhibitors, the present study evaluates a series of mono- and disubstituted derivatives of 4(3H)-quinazolinone as potential inhibitors of recombinant human MAO-A and MAO-B. Twelve C6-monosubstituted and nine N3/C6-disubstituted 4(3H)-quinazolinone derivatives were synthesised, which led to the discovery of novel quinazolinone derivatives with micromolar and submicromolar activities as inhibitors of MAO-B. The most potent mono- and disubstituted derivatives exhibited IC50 values of 6.35 μM (7f) and 0.685 μM (8b), respectively. This study identifies suitable substitution patterns for the design of 4(3H)-quinazolinone derivatives as MAO-B inhibitors.
The use of fiber-reinforced composite materials has widely spread in various sectors, including aerospace, defense, and civil industry. The assessment of these heterogeneous material systems is ...important for safer and risk-free applications and has contributed to the need for self-sensing composites. This work is focused on the development of piezoresistive composites, the prediction of their performance and structural health monitoring (SHM). Additionally, this work unpacks the complexity of carbon nanotubes (CNTs) micro-fabrication and the development of piezoresistive and electromagnetic (EM) waves detection electrodes. Scanning electron microscopy (SEM) was used to characterize the CNTs structure and morphologies. The manufactured CNTs were incorporated in epoxy systems to fabricate glass fiber reinforced polymer (GFRP)-CNTs smart composites with piezoresistive properties. The detection of micro-damage onset and its progression was carried out in mode I, to evaluate the sensitivity of the smart composites to damage development. The change in electrical conductivity of the nanotubes-reinforced composite systems due to localized mechanical strains enabled crack propagation detection. The relationship between crack propagation, fracture toughness, and electrical resistivity of the smart composite was analyzed.
To realize the great potential of nanoparticles as new materials for biomedical applications, the nanoparticles will have to be assembled in such a way that the newly created assembly will have ...unique properties that conventional materials do not possess. This will enable nanomaterials to be used for many novel applications. We have attempted to assemble silica nanoparticles to create a two-dimensional nanomaterial, which might be useful for biosensor and biochip production. The silica nanoparticles are synthesized and assembled in a monolayer fashion through the use of halogenated silanes. Photolithography techniques are used to pattern the glass surface prior to nanoparticle attachment. The concentration of the silica nanoparticles in the solution controls the surface coverage of nanoparticles on the glass surface. Different patterned silica arrays can be made with controlled surface coverage. The nanoparticle-covered surface is successfully tested for surface-enhanced enzymatic reactivity for the detection of a neurotransmitter, glutamate. This report demonstrates the feasibility of assembling nanoparticles for biosensor development.
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