This article deals with the estimation of inserted defects in bone material by photons used for r... more This article deals with the estimation of inserted defects in bone material by photons used for radiation therapy, for instance, to treat carcinogenic diseases including bone cancer. However, there are side effects by radiation on structures of bones. Structure alters electron density of states that, in time, influences biomedical reactions on bone life condition. Exoelectron emission (EEE) phenomenon underlies a new electron spectroscopy to explore alteration of the electronic structurally dependence properties of bone material. The influence of photons with different energies and the dose rate on the bone structure is discussed. The bone EEE response is not linear on the dose rate and probably is connected with interaction of radiation induced centers responsible for EEE process. EEE structural changes have varied with energy variety of doses used in radiotherapy. Keywords: X-ray / radiotherapy / exoelectron emission / dose rate / photons / bone RÉSUMÉ Estimation des défauts introduits dans l'os après une radiothérapie, au moyen d'une technique d'émission exoélectronique. Cet article porte sur l'estimation des défauts introduits dans le matériau de l'os par les photons employés en radiothérapie, par exemple, pour soigner des maladies carcinogènes, voire un cancer osseux ; il y a des effets secondaires du rayonnement sur la structure de l'os. La structure altère la densité électronique d'états ; cette altération influence, à son tour, les réactions biomédicales qui agisse sur la condition de vie de l'os. Le phénomène d'émission d'exo-électrons (EEE) sous-tend une nouvelle spectrométrie électronique permettant d'explorer l'altération des propriétés de dépendance électronique structurelle du matériau de l'os. Nous étudions l'influence de l'énergie et du débit de dose des photons sur la structure de l'os. La réponse EEE de l'os n'est pas une fonction linéaire du débit de dose ; elle est probablement associée à l'interaction de centres responsables du processus EEE, induits par le rayonnement. Les modifications structurelles EEE ont varié avec les énergies et les doses employées en radiothérapie.
NATO Science for Peace and Security Series A: Chemistry and Biology, 2011
To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mea... more To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mean free path on in a solid that is on order of nanoscale. Emission of these electrons from a solid is considered to characterize nanoobjects for sensing applications. This paper considers applications and limitations of weak electron emission for chemical and radiation sensors.
In this work, the properties of hydroxyapatite (HAP) nanoparticles (NPs) have been studied both t... more In this work, the properties of hydroxyapatite (HAP) nanoparticles (NPs) have been studied both theoretically and experimentally focusing on computational analysis. HAP is widely used to fabricate implants, for drug delivery, etc. The physical properties of the nanosized HAP particles play an important role in the interaction with cells in the human body and are of great interest. Computer simulation was employed to understand the properties of HAP clusters (Ca(5)(PO(4))(3)OH) including formation energies, dipole moments and polarization (surface charges) by molecular mechanics (MM + , OPLS) and mostly by quantum semi-empirical Hartree-Fock (PM3) methods. The size of the simulated cluster is found to affect its dipole moment, polarization, and, finally, the electron work function- ϕ. These parameters depend on the concentration of hydrogen atoms H (or protons) at the surface. Values of ϕ were experimentally estimated via photoelectron emission measurements. The magnitude of ϕ was demonstrated to have a positive correlation on sizes. The NPs demonstrated a capability to be gathered within conglomerates. This property is confirmed by the calculated data for various sizes. Their sizes have a positive correlation on ϕ by the native particles. The main results show that the distributions of dipole moments have very different space orientations (along the OX, OY and OZ axes, the OZ axis is oriented along the OH column) and change with the addition of hydrogen atoms, which saturate the broken hydrogen bonds. This electrical property of NP leads to different behaviors and motions with consequent aggregation: (1) for the case of NPs having dipole moment oriented preferably perpendicular to the OZ axis (with more hydrogen bonds saturated by added H)-the HAP NP aggregates with hexagonal orientation and forms a wider and more spherical shape (sphere-like or bundle-like); (2) for the case of NPs having dipole moment oriented along the OZ axis (as is the case in the absence of added protons or non-saturated hydrogen bonds)-the NPs firstly rotated and oriented along this axis to form the most elongated cylindrical shape (rod-like).
Surface Engineering and Applied Electrochemistry, 2012
Identification and prioritization of contaminants arising from occasional release or intentional ... more Identification and prioritization of contaminants arising from occasional release or intentional discharge in unsecured water supplies are of paramount importance to assess national and international capacities to be able to respond, sense/detect, isolate, and mitigate safety and security risk vectors in a timely manner. Using advanced and nanoscale materials, a series of novel point and stand-off sensors/detectors for continuous and in-situ monitoring of inorganic, organic, and microbiological pollutants are described. The study is concurrent to our existing efforts to develop remediation strategies for region specific contaminants, defining water quality, modeling of process function water system design, and enhancing water resiliency. New sensing approaches based on interaction of a semiconductor surface with emitting electrons and metal-complexes-based chiroptical switches are also described.
The electronic structure and self-polarization of P(VDF-TrFE) Langmuir-Blodgett nanofilms were an... more The electronic structure and self-polarization of P(VDF-TrFE) Langmuir-Blodgett nanofilms were analyzed under temperature-driven phase transitions, according to their thickness, composition, and structural conformation. Both thermo-stimulated exoelectron emission (TSEE) spectroscopy and computational simulation, including quantum-chemical calculations from first principles, were carried out. PVDF and composite P(VDF-TrFE) (70:30) molecular chains as Trans and Gauche conformers, as well as crystal cells, were modeled for these TSEE analyses. The quantum-chemical calculations and the computational simulation were based on the density functional theory (DFT) as well as semi-empirical (PM3) methods. It was demonstrated that the energy of electron states, as well as the total energies of the studied P(VDF-TrFE) molecular clusters during phase transformation, is influenced by electron work function and electron affinity. Analysis was performed by combining TSEE experimental data with the computational data of the molecular models, demonstrating the effectiveness of this joint approach. For the first time, TSEE was used for contactless measurements of nanofilm polarization, and characterization of the phase transition. The proposed new method can be widely applied in nanobiomedicine, particularly in development of new bone bio-implants, including built-in sensors (new smart nanotechnology).
This article belongs to a three-part series dedicated to the simultaneous measurements of thermal... more This article belongs to a three-part series dedicated to the simultaneous measurements of thermally stimulated exo-electron emission (TSEE), desorption (TSD) and luminescence (TSL). These works aim is to verify the ability of the applied experimental setup to characterize and analyze at the same time all the three above-mentioned stimulated processes. In agreement with the two preceding publications that deal TSD and TSEE, this article proves the consistency of the results of the individual modes of joint measurements of TSL and TSEE (as well as bulk and surface, the corresponding sources of emission, the recombination processes and their interactions). The whole experimental apparatus was tested using a well-known material, high-purity monocrystalline KBr, in the temperature range ΔT = −196 °C–430 °C (ΔT = 77 K–703 K) and in the chamber with base pressure p
Tungsten micro- and nanoparticle structured composite have been demonstrated recently as a promis... more Tungsten micro- and nanoparticle structured composite have been demonstrated recently as a promising material for protection of the radiation therapy patient against radiation. The shielding properties of the composite to a great extent depends on the homogeneity. The present research concentrates on the experimental investigation of the homogeneity of the synthesized composite in dependence on the material mixing methods, particle size, and concentration. The material radiation attenuation properties were explored as well. It was observed that the tendency to form agglomerates becomes greater if tungsten particle size decreases. The best particle distribution uniformity in the composite was obtained with ultrasound disperser. Most effective radiation absorption was observed for the samples with a particle size of 500 nm and 50 nm.
Mesenchymal stem cells (MSCs) and osteoblasts respond to the surface electrical charge and topogr... more Mesenchymal stem cells (MSCs) and osteoblasts respond to the surface electrical charge and topography of biomaterials. This work focuses on the connection between the roughness of calcium phosphate (CP) surfaces and their electrical potential (EP) at the micro- and nanoscales and the possible role of these parameters in jointly affecting human MSC osteogenic differentiation and maturation in vitro. A microarc CP coating was deposited on titanium substrates and characterized at the micro- and nanoscale. Human adult adipose-derived MSCs (hAMSCs) or prenatal stromal cells from the human lung (HLPSCs) were cultured on the CP surface to estimate MSC behavior. The roughness, nonuniform charge polarity, and EP of CP microarc coatings on a titanium substrate were shown to affect the osteogenic differentiation and maturation of hAMSCs and HLPSCs in vitro. The surface EP induced by the negative charge increased with increasing surface roughness at the microscale. The surface relief at the nan...
Nato Science For Peace and Security Series a Chemistry and Biology, 2012
To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mea... more To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mean free path on in a solid that is on order of nanoscale. Emission of these electrons from a solid is considered to characterize nanoobjects for sensing applications. This paper considers applications and limitations of weak electron emission for chemical and radiation sensors.
Intensity Modulated Radiotherapy (IMRT) is extensively used for cancer patients treatment in mode... more Intensity Modulated Radiotherapy (IMRT) is extensively used for cancer patients treatment in modern Radiotherapy Clinics. Patient-related Quality Control (QC) is essential part of IMRT clinical implementation, as fluencies of Intensity Modulated (IM) fields has to be independently verified prior to delivery of the IMRT plan to the patient. In most cases, combination or ionometric and film dosimetry is in use for patient-related QC. The aim of this study was to evaluate volume-averaging effect of different ionization chambers used for ionometric dosimetry of the IMRT fields.
Compact device of high sensitivity for measurement of the refractive indices of both stationary a... more Compact device of high sensitivity for measurement of the refractive indices of both stationary and flowing liquids has been developed. This device can be used to analyse a variety of biomedical liquids: urine, serum protein. The refractive index (RI) is determined by measuring the deviation of a laser beam passing through a cylindrical cell containing the test liquid. In order to significantly improve the resolution and stability of RI measurements, the repeated reflections and refractions of the light beam travelling through the cylindrical cell are employed.
Most of diagnostic radiography today is digital. Therefore there is a great possibility to make a... more Most of diagnostic radiography today is digital. Therefore there is a great possibility to make an express check of an x-ray beam quality using digital approach. The flux of the x-ray photons detected is governed by the Poisson statistics. The deviation of the radiating technique modes leads from the Poisson statistics. Because the single element of a digital detector matrix produces the signal that is directly proportional to the number of the absorbed photons, the brightness distribution is in use to estimate the statistics of the photons. This is demonstrated to evaluate quality of x-ray beam of the digital x-ray diagnostic equipment.
Work was studied in the composite material (tungsten and ceresin composite material) absorption a... more Work was studied in the composite material (tungsten and ceresin composite material) absorption and scattering characteristics as well as comparison with until now used Bi-Sn-Pb compound. the hypothesis is that this type of composite material can be used as a substitute for metal alloy in radiation therapy. The aim is to determine the absorption and scatter of the composite, as well as to find out whether this kind of material can be applied to radiation therapy.
We have applied novel technique for enhancing bone tissue formation on micro- and nanostructured ... more We have applied novel technique for enhancing bone tissue formation on micro- and nanostructured calcium phosphate (CP) coatings. CP surfaces with “primitive” physical-chemical composition, which is not corresponding to last one in bone, have an active effect on functional properties of mesenchymal stromal cell pull (MSCP). The studied micro-CP coatings, characterized by marked roughness of surface had an osteoinductive potential up to 100 %. Relief of CP coatings from HAP nanoparticles (30–50 nm) does not practically differ from ones designed by use of HAP microparticles. Roughness of all CP nanocoatings had average Ra=5.13−6.43 µm and Rz=18.71−24.16 µm that was corresponded to CP microcoatings one. Probability of bone plate formation on CP nanostructured coatings was only 12.5 %. Hydrogenation of the CP surface layer increased its negative charge that was evaluated by means of photoelectron work function (ϕ) measurement. An increment of ϕ at the values of ≈0.1−1 eV was supplied. T...
An x-ray digital imaging technology in use in xray diagnostics makes it possible to achieve a dig... more An x-ray digital imaging technology in use in xray diagnostics makes it possible to achieve a digital evaluation of image quality. Histograms on image brightness over the pixels were processed. Variance and an average of the histograms correlated to a contrast. This approach demonstrates a simple, fast method for evaluating the quality of a digital x-ray image.
This article deals with the estimation of inserted defects in bone material by photons used for r... more This article deals with the estimation of inserted defects in bone material by photons used for radiation therapy, for instance, to treat carcinogenic diseases including bone cancer. However, there are side effects by radiation on structures of bones. Structure alters electron density of states that, in time, influences biomedical reactions on bone life condition. Exoelectron emission (EEE) phenomenon underlies a new electron spectroscopy to explore alteration of the electronic structurally dependence properties of bone material. The influence of photons with different energies and the dose rate on the bone structure is discussed. The bone EEE response is not linear on the dose rate and probably is connected with interaction of radiation induced centers responsible for EEE process. EEE structural changes have varied with energy variety of doses used in radiotherapy. Keywords: X-ray / radiotherapy / exoelectron emission / dose rate / photons / bone RÉSUMÉ Estimation des défauts introduits dans l'os après une radiothérapie, au moyen d'une technique d'émission exoélectronique. Cet article porte sur l'estimation des défauts introduits dans le matériau de l'os par les photons employés en radiothérapie, par exemple, pour soigner des maladies carcinogènes, voire un cancer osseux ; il y a des effets secondaires du rayonnement sur la structure de l'os. La structure altère la densité électronique d'états ; cette altération influence, à son tour, les réactions biomédicales qui agisse sur la condition de vie de l'os. Le phénomène d'émission d'exo-électrons (EEE) sous-tend une nouvelle spectrométrie électronique permettant d'explorer l'altération des propriétés de dépendance électronique structurelle du matériau de l'os. Nous étudions l'influence de l'énergie et du débit de dose des photons sur la structure de l'os. La réponse EEE de l'os n'est pas une fonction linéaire du débit de dose ; elle est probablement associée à l'interaction de centres responsables du processus EEE, induits par le rayonnement. Les modifications structurelles EEE ont varié avec les énergies et les doses employées en radiothérapie.
NATO Science for Peace and Security Series A: Chemistry and Biology, 2011
To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mea... more To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mean free path on in a solid that is on order of nanoscale. Emission of these electrons from a solid is considered to characterize nanoobjects for sensing applications. This paper considers applications and limitations of weak electron emission for chemical and radiation sensors.
In this work, the properties of hydroxyapatite (HAP) nanoparticles (NPs) have been studied both t... more In this work, the properties of hydroxyapatite (HAP) nanoparticles (NPs) have been studied both theoretically and experimentally focusing on computational analysis. HAP is widely used to fabricate implants, for drug delivery, etc. The physical properties of the nanosized HAP particles play an important role in the interaction with cells in the human body and are of great interest. Computer simulation was employed to understand the properties of HAP clusters (Ca(5)(PO(4))(3)OH) including formation energies, dipole moments and polarization (surface charges) by molecular mechanics (MM + , OPLS) and mostly by quantum semi-empirical Hartree-Fock (PM3) methods. The size of the simulated cluster is found to affect its dipole moment, polarization, and, finally, the electron work function- ϕ. These parameters depend on the concentration of hydrogen atoms H (or protons) at the surface. Values of ϕ were experimentally estimated via photoelectron emission measurements. The magnitude of ϕ was demonstrated to have a positive correlation on sizes. The NPs demonstrated a capability to be gathered within conglomerates. This property is confirmed by the calculated data for various sizes. Their sizes have a positive correlation on ϕ by the native particles. The main results show that the distributions of dipole moments have very different space orientations (along the OX, OY and OZ axes, the OZ axis is oriented along the OH column) and change with the addition of hydrogen atoms, which saturate the broken hydrogen bonds. This electrical property of NP leads to different behaviors and motions with consequent aggregation: (1) for the case of NPs having dipole moment oriented preferably perpendicular to the OZ axis (with more hydrogen bonds saturated by added H)-the HAP NP aggregates with hexagonal orientation and forms a wider and more spherical shape (sphere-like or bundle-like); (2) for the case of NPs having dipole moment oriented along the OZ axis (as is the case in the absence of added protons or non-saturated hydrogen bonds)-the NPs firstly rotated and oriented along this axis to form the most elongated cylindrical shape (rod-like).
Surface Engineering and Applied Electrochemistry, 2012
Identification and prioritization of contaminants arising from occasional release or intentional ... more Identification and prioritization of contaminants arising from occasional release or intentional discharge in unsecured water supplies are of paramount importance to assess national and international capacities to be able to respond, sense/detect, isolate, and mitigate safety and security risk vectors in a timely manner. Using advanced and nanoscale materials, a series of novel point and stand-off sensors/detectors for continuous and in-situ monitoring of inorganic, organic, and microbiological pollutants are described. The study is concurrent to our existing efforts to develop remediation strategies for region specific contaminants, defining water quality, modeling of process function water system design, and enhancing water resiliency. New sensing approaches based on interaction of a semiconductor surface with emitting electrons and metal-complexes-based chiroptical switches are also described.
The electronic structure and self-polarization of P(VDF-TrFE) Langmuir-Blodgett nanofilms were an... more The electronic structure and self-polarization of P(VDF-TrFE) Langmuir-Blodgett nanofilms were analyzed under temperature-driven phase transitions, according to their thickness, composition, and structural conformation. Both thermo-stimulated exoelectron emission (TSEE) spectroscopy and computational simulation, including quantum-chemical calculations from first principles, were carried out. PVDF and composite P(VDF-TrFE) (70:30) molecular chains as Trans and Gauche conformers, as well as crystal cells, were modeled for these TSEE analyses. The quantum-chemical calculations and the computational simulation were based on the density functional theory (DFT) as well as semi-empirical (PM3) methods. It was demonstrated that the energy of electron states, as well as the total energies of the studied P(VDF-TrFE) molecular clusters during phase transformation, is influenced by electron work function and electron affinity. Analysis was performed by combining TSEE experimental data with the computational data of the molecular models, demonstrating the effectiveness of this joint approach. For the first time, TSEE was used for contactless measurements of nanofilm polarization, and characterization of the phase transition. The proposed new method can be widely applied in nanobiomedicine, particularly in development of new bone bio-implants, including built-in sensors (new smart nanotechnology).
This article belongs to a three-part series dedicated to the simultaneous measurements of thermal... more This article belongs to a three-part series dedicated to the simultaneous measurements of thermally stimulated exo-electron emission (TSEE), desorption (TSD) and luminescence (TSL). These works aim is to verify the ability of the applied experimental setup to characterize and analyze at the same time all the three above-mentioned stimulated processes. In agreement with the two preceding publications that deal TSD and TSEE, this article proves the consistency of the results of the individual modes of joint measurements of TSL and TSEE (as well as bulk and surface, the corresponding sources of emission, the recombination processes and their interactions). The whole experimental apparatus was tested using a well-known material, high-purity monocrystalline KBr, in the temperature range ΔT = −196 °C–430 °C (ΔT = 77 K–703 K) and in the chamber with base pressure p
Tungsten micro- and nanoparticle structured composite have been demonstrated recently as a promis... more Tungsten micro- and nanoparticle structured composite have been demonstrated recently as a promising material for protection of the radiation therapy patient against radiation. The shielding properties of the composite to a great extent depends on the homogeneity. The present research concentrates on the experimental investigation of the homogeneity of the synthesized composite in dependence on the material mixing methods, particle size, and concentration. The material radiation attenuation properties were explored as well. It was observed that the tendency to form agglomerates becomes greater if tungsten particle size decreases. The best particle distribution uniformity in the composite was obtained with ultrasound disperser. Most effective radiation absorption was observed for the samples with a particle size of 500 nm and 50 nm.
Mesenchymal stem cells (MSCs) and osteoblasts respond to the surface electrical charge and topogr... more Mesenchymal stem cells (MSCs) and osteoblasts respond to the surface electrical charge and topography of biomaterials. This work focuses on the connection between the roughness of calcium phosphate (CP) surfaces and their electrical potential (EP) at the micro- and nanoscales and the possible role of these parameters in jointly affecting human MSC osteogenic differentiation and maturation in vitro. A microarc CP coating was deposited on titanium substrates and characterized at the micro- and nanoscale. Human adult adipose-derived MSCs (hAMSCs) or prenatal stromal cells from the human lung (HLPSCs) were cultured on the CP surface to estimate MSC behavior. The roughness, nonuniform charge polarity, and EP of CP microarc coatings on a titanium substrate were shown to affect the osteogenic differentiation and maturation of hAMSCs and HLPSCs in vitro. The surface EP induced by the negative charge increased with increasing surface roughness at the microscale. The surface relief at the nan...
Nato Science For Peace and Security Series a Chemistry and Biology, 2012
To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mea... more To characterize nanoobjects, a non-contact technique is preferable. Low energy electron has a mean free path on in a solid that is on order of nanoscale. Emission of these electrons from a solid is considered to characterize nanoobjects for sensing applications. This paper considers applications and limitations of weak electron emission for chemical and radiation sensors.
Intensity Modulated Radiotherapy (IMRT) is extensively used for cancer patients treatment in mode... more Intensity Modulated Radiotherapy (IMRT) is extensively used for cancer patients treatment in modern Radiotherapy Clinics. Patient-related Quality Control (QC) is essential part of IMRT clinical implementation, as fluencies of Intensity Modulated (IM) fields has to be independently verified prior to delivery of the IMRT plan to the patient. In most cases, combination or ionometric and film dosimetry is in use for patient-related QC. The aim of this study was to evaluate volume-averaging effect of different ionization chambers used for ionometric dosimetry of the IMRT fields.
Compact device of high sensitivity for measurement of the refractive indices of both stationary a... more Compact device of high sensitivity for measurement of the refractive indices of both stationary and flowing liquids has been developed. This device can be used to analyse a variety of biomedical liquids: urine, serum protein. The refractive index (RI) is determined by measuring the deviation of a laser beam passing through a cylindrical cell containing the test liquid. In order to significantly improve the resolution and stability of RI measurements, the repeated reflections and refractions of the light beam travelling through the cylindrical cell are employed.
Most of diagnostic radiography today is digital. Therefore there is a great possibility to make a... more Most of diagnostic radiography today is digital. Therefore there is a great possibility to make an express check of an x-ray beam quality using digital approach. The flux of the x-ray photons detected is governed by the Poisson statistics. The deviation of the radiating technique modes leads from the Poisson statistics. Because the single element of a digital detector matrix produces the signal that is directly proportional to the number of the absorbed photons, the brightness distribution is in use to estimate the statistics of the photons. This is demonstrated to evaluate quality of x-ray beam of the digital x-ray diagnostic equipment.
Work was studied in the composite material (tungsten and ceresin composite material) absorption a... more Work was studied in the composite material (tungsten and ceresin composite material) absorption and scattering characteristics as well as comparison with until now used Bi-Sn-Pb compound. the hypothesis is that this type of composite material can be used as a substitute for metal alloy in radiation therapy. The aim is to determine the absorption and scatter of the composite, as well as to find out whether this kind of material can be applied to radiation therapy.
We have applied novel technique for enhancing bone tissue formation on micro- and nanostructured ... more We have applied novel technique for enhancing bone tissue formation on micro- and nanostructured calcium phosphate (CP) coatings. CP surfaces with “primitive” physical-chemical composition, which is not corresponding to last one in bone, have an active effect on functional properties of mesenchymal stromal cell pull (MSCP). The studied micro-CP coatings, characterized by marked roughness of surface had an osteoinductive potential up to 100 %. Relief of CP coatings from HAP nanoparticles (30–50 nm) does not practically differ from ones designed by use of HAP microparticles. Roughness of all CP nanocoatings had average Ra=5.13−6.43 µm and Rz=18.71−24.16 µm that was corresponded to CP microcoatings one. Probability of bone plate formation on CP nanostructured coatings was only 12.5 %. Hydrogenation of the CP surface layer increased its negative charge that was evaluated by means of photoelectron work function (ϕ) measurement. An increment of ϕ at the values of ≈0.1−1 eV was supplied. T...
An x-ray digital imaging technology in use in xray diagnostics makes it possible to achieve a dig... more An x-ray digital imaging technology in use in xray diagnostics makes it possible to achieve a digital evaluation of image quality. Histograms on image brightness over the pixels were processed. Variance and an average of the histograms correlated to a contrast. This approach demonstrates a simple, fast method for evaluating the quality of a digital x-ray image.
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