Microdosimetric Investigation and a Novel Model of Radiosensitization in the Presence of Metallic Nanoparticles

Auger cascades generated in high atomic number nanoparticles (NPs) following ionization were considered a potential mechanism for NP radiosensitization. In this work, we investigated the microdosimetric consequences of the Auger cascades using the theory of dual radiation action (TDRA), and we propose the novel Bomb model as a general framework for describing NP-related radiosensitization. When triggered by an ionization event, the Bomb model considers the NPs that are close to a radiation sensitive cellular target, generates dense secondary electrons and kills the cells according to a probability distribution, acting like a “bomb.” TDRA plus a distance model were used as the theoretical basis for calculating the change in α of the linear-quadratic survival model and the relative biological effectiveness (RBE). We calculated these quantities for SQ20B and Hela human cancer cells under 250 kVp X-ray irradiation with the presence of gadolinium-based NPs (AGuIXTM), and 220 kVp X-ray irradiation with the presence of 50 nm gold NPs (AuNPs), respectively, and compared with existing experimental data. Geant4-based Monte Carlo (MC) simulations were used to (1) generate the electron spectrum and the phase space data of photons entering the NPs and (2) calculate the proximity functions and other related parameters for the TDRA and the Bomb model. The Auger cascade electrons had a greater proximity function than photoelectric and Compton electrons in water by up to 30%, but the resulting increases in α were smaller than those derived from experimental data. The calculated RBEs cannot explain the experimental findings. The relative increase in α predicted by TDRA was lower than the experimental result by a factor of at least 45 for SQ20B cells with AGuIX under 250 kVp X-ray irradiation, and at least four for Hela cells with AuNPs under 220 kVp X-ray irradiation. The application of the Bomb model to Hela cells with AuNPs under 220 kVp X-ray irradiation indicated that a single ionization event for NPs caused by higher energy photons has a higher probability of killing a cell. NPs that are closer to the cell nucleus are more effective for radiosensitization. Microdosimetric calculations of the RBE for cell death of the Auger electron cascade cannot explain the experimentally observed radiosensitization by AGuIX or AuNP, while the proposed Bomb model is a potential candidate for describing NP-related radiosensitization at low NP concentrations.

Download Full-text

Ionizing Radiation Effects Modelling in Cells Population with Gold Nanoparticles

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v17n5.2075 ◽

2021 ◽

Vol 17 (5) ◽

pp. 659-669

Author(s):

Hamizah Rashid ◽

Fuaada Mohd Siam ◽

Normah Maan ◽

Wan Nordiana W Abd Rahman

Keyword(s):

Experimental Data ◽

Gold Nanoparticles ◽

Ionizing Radiation ◽

Gold Nanoparticle ◽

Radiation Effects ◽

Radiation Treatment ◽

Experimental Result ◽

Linear Quadratic ◽

Cancer Cell Death ◽

Matlab Programming

Radiosensitizer such as gold nanoparticle is a promising agent to be used in radiotherapy to increase the number of cancer cell death. Gold nanoparticle increases the production of the secondary electron after being hit by primary radiation that will cause DNA damage. The gold nanoparticle can be targeted to specific cancer cells and therefore reduce damage to the healthy nearby cell. Thus, nanoparticles will elevate the efficacy of radiation treatment without delivering a high radiation dose that will damage the organ at risk. Therefore, this paper aimed to study the effects of radiosensitizer on radiation therapy. The study was done by incorporating the function of dose deposited by gold nanoparticles into the existing model of ionizing radiation effects. The model was mathematically described using Ordinary Differential Equations (ODEs). The simulation results were fitted to the Linear Quadratic (LQ) formulation to give the ratio for a/b. Next, the parameter estimation and sensitivity analysis of the model are carried out using experimental data of HeLa cell with the aid of the MATLAB programming. The estimated parameter values can explain the radiobiology process, which can support the result of the experimental design. The result showed that the sum-squared error (SSE) between simulation data and experimental data obtained is 0.015 which indicates an excellent fit to the experimental data. Thus, this model is in line with the experimental result. The model is able to explain the dynamics process of ionizing radiation effects with gold nanoparticles on the cell population.

Download Full-text

Evidence for ordered Fe3Ni

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125981 ◽

1987 ◽

Vol 45 ◽

pp. 216-217

Author(s):

K.B. Reuter ◽

D.B. Williams ◽

J.I. Goldstein

Keyword(s):

Experimental Data ◽

Martensitic Transformation ◽

Electron Diffraction ◽

Room Temperature ◽

Direct Evidence ◽

Transformation Product ◽

Iron Meteorites ◽

X Ray ◽

Ni Content ◽

Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Download Full-text

Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽

10.3390/ma14102518 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2518

Author(s):

Dorota Kołodyńska ◽

Yongming Ju ◽

Małgorzata Franus ◽

Wojciech Franus

Keyword(s):

Experimental Data ◽

Aspartic Acid ◽

Ph Value ◽

Complexing Agents ◽

X Ray Diffraction ◽

Experimental Conditions ◽

Modified Zeolite ◽

X Ray ◽

Slow Release Fertilizers ◽

Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

Download Full-text

Phase Relations in the ZrO2-MgO-FeOx System: Experimental Data and Assessment of Thermodynamic Parameters

Journal of Phase Equilibria and Diffusion ◽

10.1007/s11669-021-00876-y ◽

2021 ◽

Author(s):

Ivan Saenko ◽

O. Fabrichnaya

Keyword(s):

Electron Microscopy ◽

Experimental Data ◽

Solid Solution ◽

Thermodynamic Parameters ◽

Spinel Phase ◽

Experimental Investigations ◽

X Ray ◽

Heat Treated ◽

Preliminary Phase ◽

Scanning Electron

AbstractThermodynamic parameters were assessed for the MgO–FeOx system and combined with already available descriptions of ZrO2-FeOx and ZrO2-MgO systems to calculate preliminary phase diagrams for planning experimental investigations. Samples of selected compositions were heat treated at 1523, 1673 and 1873 K and characterized using x-ray and scanning electron microscopy combined with energy dispersive x-ray spectroscopy (SEM/EDX). Experiments indicated extension of cubic ZrO2 solid solution into the ternary system at 1873 K (75 mol.% ZrO2, 10 mol.% FeOx and 15 mol.% MgO) and limited solubility of 4 mol.% ZrO2 in spinel phase. Based on the obtained results thermodynamic parameters of C-ZrO2 and spinel phase were optimized.

Download Full-text

Solid-State Ball-Milling of Co3O4 Nano/Microspheres and Carbon Black Endorsed LaMnO3 Perovskite Catalyst for Bifunctional Oxygen Electrocatalysis

Catalysts ◽

10.3390/catal11010076 ◽

2021 ◽

Vol 11 (1) ◽

pp. 76

Author(s):

Chelladurai Karuppiah ◽

Balamurugan Thirumalraj ◽

Srinivasan Alagar ◽

Shakkthivel Piraman ◽

Ying-Jeng Jame Li ◽

...

Keyword(s):

Electron Microscopy ◽

Energy Storage ◽

Fuel Cell ◽

Solid State ◽

Carbon Black ◽

Ball Milling ◽

Potential Candidate ◽

X Ray ◽

Bifunctional Electrocatalyst ◽

Bet Analysis

Developing a highly stable and non-precious, low-cost, bifunctional electrocatalyst is essential for energy storage and energy conversion devices due to the increasing demand from the consumers. Therefore, the fabrication of a bifunctional electrocatalyst is an emerging focus for the promotion and dissemination of energy storage/conversion devices. Spinel and perovskite transition metal oxides have been widely explored as efficient bifunctional electrocatalysts to replace the noble metals in fuel cell and metal-air batteries. In this work, we developed a bifunctional catalyst for oxygen reduction and oxygen evolution reaction (ORR/OER) study using the mechanochemical route coupling of cobalt oxide nano/microspheres and carbon black particles incorporated lanthanum manganite perovskite (LaMnO3@C-Co3O4) composite. It was synthesized through a simple and less-time consuming solid-state ball-milling method. The synthesized LaMnO3@C-Co3O4 composite was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction spectroscopy, and micro-Raman spectroscopy techniques. The electrocatalysis results showed excellent electrochemical activity towards ORR/OER kinetics using LaMnO3@C-Co3O4 catalyst, as compared with Pt/C, bare LaMnO3@C, and LaMnO3@C-RuO2 catalysts. The observed results suggested that the newly developed LaMnO3@C-Co3O4 electrocatalyst can be used as a potential candidate for air-cathodes in fuel cell and metal-air batteries.

Download Full-text

Enhancing removal efficiency of anionic dye (Cibacron blue) using waste potato peels powder

Scientific Reports ◽

10.1038/s41598-020-79069-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kahina Bouhadjra ◽

Wahiba Lemlikchi ◽

Azedine Ferhati ◽

Samuel Mignard

Keyword(s):

Experimental Data ◽

Contact Time ◽

Potato Peel ◽

X Ray ◽

Cibacron Blue ◽

Anionic Dye ◽

Experimental Parameters ◽

Optimum Ph ◽

Potato Peels ◽

Scanning Electron

AbstractIn the present study, the potato peel waste (PP) was used for the removal of the anionic dye Cibacron Blue P3R from an aqueous solution, activated with phosphoric acid (PPa) and calcined at 800 °C (PPc). The materials were characterized by Scanning Electron Microscope, Energy dispersive X-ray analysis and Fourier Transform Infrared Spectroscopy. The effects of various experimental parameters (pH, dye concentration, contact time) were also studied. The experimental results have shown that PPc has a greater capacity compared to pp and ppa. The capacity of PP bio-char (PPc) is 270.3 mg g−1 compared to PP (100 mg g−1) and PPa (125 mg g−1). Equilibrium experiments at 180 min for all materials were carried out at optimum pH (2.2): 76.41, 88.6 and 94% for PP, PPa and PPc respectively; and the Langmuir models agreed very well with experimental data. The ability of sorbent for the sorption of CB dye follows this order: calcined > activated > native materials. Potato peel biochar (PPc) can be considered a promising adsorbent for removing persistent dyes from water.

Download Full-text

Synthesis, Cytotoxic Activity, Crystal Structure, DFT Studies and Molecular Docking of 3-Amino-1-(2,5-dichlorophenyl)-8-methoxy-1H-benzo[f]chromene-2-carbonitrile

Crystals ◽

10.3390/cryst11020184 ◽

2021 ◽

Vol 11 (2) ◽

pp. 184

Author(s):

Menna El Gaafary ◽

Tatiana Syrovets ◽

Hany M. Mohamed ◽

Ahmed A. Elhenawy ◽

Ahmed M. El-Agrody ◽

...

Keyword(s):

Cytotoxic Activity ◽

Cell Lines ◽

Cancer Cell ◽

Dna Methyltransferase ◽

Human Cancer ◽

Theoretical Calculations ◽

Cancer Cell Lines ◽

Molecular Structures ◽

Cytotoxic Activities ◽

X Ray

The target compound 3-amino-1-(2,5-d ichlorophenyl)-8-methoxy-1H-benzo[f]-chromene-2-carbonitrile (4) was synthesized via a reaction of 6-methoxynaphthalen-2-ol (1), 2,5-dichlorobenzaldehyde (2), and malononitrile (3) in ethanolic piperidine solution under microwave irradiation. The newly synthesized β-enaminonitrile was characterized by FT-IR, 1H NMR, 13C NMR, mass spectroscopy, elemental analysis and X-ray diffraction data. Its cytotoxic activity was evaluated against three different human cancer cell lines MDA-MB-231, A549, and MIA PaCa-2 in comparison to the positive controls etoposide and camptothecin employing the XTT cell viability assay. The analysis of the Hirshfeld surface was utilized to visualize the reliability of the crystal package. The obtained results confirmed that the tested molecule revealed promising cytotoxic activities against the three cancer cell lines. Furthermore, theoretical calculations (DFT) were carried out with the Becke3-Lee-Yang-parr (B3LYP) level using 6-311++G(d,p) basis. The optimization geometry for molecular structures was in agreement with the X-ray structure data. The HOMO-LUMO energy gap of the studied system was discussed. The intermolecular-interactions were studied through analysis of the topological-electron-density(r) using the QTAIM and NCI methods. The novel compound exhibited favorable ADMET properties and its molecular modeling analysis showed strong interaction with DNA methyltransferase 1.

Download Full-text

Bacterial influence on the formation of hematite: implications for Martian dormant life

International Journal of Astrobiology ◽

10.1017/s1473550421000124 ◽

2021 ◽

pp. 1-15

Author(s):

Sudeera Wickramarathna ◽

Rohana Chandrajith ◽

Atula Senaratne ◽

Varun Paul ◽

Padmanava Dash ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Soil Layer ◽

Soil Samples ◽

Mineral Weathering ◽

Compositional Variation ◽

Rrna Gene ◽

Potential Candidate ◽

Metabolic Processes ◽

Extraterrestrial Life ◽

X Ray

Abstract Previous exploration missions have revealed Mars as a potential candidate for the existence of extraterrestrial life. If life could have existed beneath the Martian subsurface, biosignatures would have been preserved in iron-rich minerals. Prior investigations of terrestrial biosignatures and metabolic processes of geological analogues would be beneficial for identifying past metabolic processes on Mars, particularly morphological and chemical signatures indicative of past life, where biological components could potentially be denatured following continued exposure to extreme conditions. The objective of the research was to find potential implications for Martian subsurface life by characterizing morphological, mineralogical and microbial signatures of hematite deposits, both hematite rock and related soil samples, collected from Highland Complex of Sri Lanka. Rock samples examined through scanning electron microscopy-energy dispersive X-ray (SEM-EDX) spectroscopy. Analysis showed globular and spherical growth layers nucleated by bacteria. EDX results showed a higher iron to oxygen ratio in nuclei colonies compared to growth layers, which indicated a compositional variation due to microbial interaction. X-ray diffraction analysis of the hematite samples revealed variations in chemical composition along the vertical soil profile, with the top surface soil layer being particularly enriched with Fe2O3, suggesting internal dissolution of hematite through weathering. Furthermore, inductively coupled plasma-mass spectrometry analyses carried out on both rock and soil samples showed a possible indication of microbially induced mineral-weathering, particularly release of trapped trace metals in the parent rock. Microbial diversity analysis using 16S rRNA gene sequencing revealed that the rock sample was dominated by Actinobacteria and Proteobacteria, specifically, members of iron-metabolizing bacterial genera, including Mycobacterium, Arthrobacter, Amycolatopsis, Nocardia and Pedomicrobium. These results suggest that morphological and biogeochemical clues derived from studying the role of bacterial activity in hematite weathering and precipitation processes can be implemented as potential comparative tools to interpret similar processes that could have occurred on early Mars.

Download Full-text

Apoptotic effect of novel pyrazolone-based derivative [Cu(PMPP-SAL)(EtOH)] on HeLa cells and its mechanism

Scientific Reports ◽

10.1038/s41598-020-75173-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Delizhaer Reheman ◽

Jing Zhao ◽

Shan Guan ◽

Guan-Cheng Xu ◽

Yi-Jie Li ◽

...

Keyword(s):

Cell Cycle ◽

Cervical Cancer ◽

Hela Cells ◽

Copper Complexes ◽

Antibacterial Properties ◽

Inhibitory Effect ◽

Parp Cleavage ◽

Potential Candidate ◽

Tnf Α

Abstract Pyrazolone complexes have strong anti-tumor and antibacterial properties, but the anti-tumor mechanism of pyrazolone-based copper complexes has not been fully understood. In this study, the possible mechanism and the inhibitory effect of a novel pyrazolone-based derivative compound [Cu(PMPP-SAL)(EtOH)] on human cervical cancer cells (HeLa cells) was investigated. [Cu(PMPP-SAL)(EtOH)] effectively inhibited proliferation of HeLa cells in vitro with an IC50 value of 2.082 after treatment for 72 h. Cell cycle analysis showed apoptosis was induced by blocking the cell cycle in the S phase. [Cu(PMPP-SAL)(EtOH)] promoted the loss of mitochondrial membrane potential, release of cytochrome c, PARP cleavage, and activation of caspase-3/9 in HeLa cells. Additionally, [Cu(PMPP-SAL)(EtOH)] inhibited the PI3K/AKT pathway and activated the P38/MAPK, and JNK/MAPK pathways. [Cu(PMPP-SAL)(EtOH)] also inhibited the phosphorylation of Iκ-Bα in the NF-κB pathway activated by TNF-α, thus restricting the proliferation of HeLa cells which were activated by TNF-α. In conclusion, [Cu(PMPP-SAL)(EtOH)] inhibited the growth of HeLa cells and induced apoptosis possibly via the caspase-dependent mitochondria-mediated pathway. These results suggest that [Cu(PMPP-SAL)(EtOH)] can be a potential candidate for the treatment of cervical cancer.

Download Full-text

Unbinding of Hyaluronan Accelerates the Enzymatic Activity of Bee Hyaluronidase

Journal of Biological Chemistry ◽

10.1074/jbc.m111.263731 ◽

2011 ◽

Vol 286 (41) ◽

pp. 35699-35707 ◽

Cited By ~ 2

Author(s):

Attila Iliás ◽

Károly Liliom ◽

Brigitte Greiderer-Kleinlercher ◽

Stephan Reitinger ◽

Günter Lepperdinger

Keyword(s):

Experimental Data ◽

Quartz Crystal ◽

Surface Loop ◽

X Ray ◽

Site Model ◽

Substrate Interaction ◽

Close Proximity ◽

Binding Groove ◽

The One ◽

Best Fit

Hyaluronan (HA), a polymeric glycosaminoglycan ubiquitously present in higher animals, is hydrolyzed by hyaluronidases (HAases). Here, we used bee HAase as a model enzyme to study the HA-HAase interaction. Located in close proximity to the active center, a bulky surface loop, which appears to obstruct one end of the substrate binding groove, was found to be functionally involved in HA turnover. To better understand kinetic changes in substrate interaction, binding of high molecular weight HA to catalytically inactive HAase was monitored by means of quartz crystal microbalance technology. Replacement of the delimiting loop by a tetrapeptide interconnection increased the affinity for HA up to 100-fold, with a KD below 1 nm being the highest affinity among HA-binding proteins surveyed so far. The experimental data of HA-HAase interaction were further validated showing best fit to the theoretically proposed sequential two-site model. Besides the one, which had been shown previously in course of x-ray structure determination, a previously unrecognized binding site works in conjunction with an unbinding loop that facilitates liberation of hydrolyzed HA.

Download Full-text