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Статті в журналах з теми "Nanoparticle beams"

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Автор: Grafiati

Опубліковано: 8 червня 2024

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1

Gagliardi, Frank M., Rick D. Franich, and Moshi Geso. "Nanoparticle dose enhancement of synchrotron radiation in PRESAGE dosimeters." Journal of Synchrotron Radiation 27, no. 6 (October 23, 2020): 1590–600. http://dx.doi.org/10.1107/s1600577520012849.

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The physical absorbed dose enhancement by the inclusion of gold and bismuth nanoparticles fabricated into water-equivalent PRESAGE dosimeters was investigated. Nanoparticle-loaded water-equivalent PRESAGE dosimeters were irradiated with superficial, synchrotron and megavoltage X-ray beams. The change in optical density of the dosimeters was measured using UV–Vis spectrophotometry pre- and post-irradiation using a wavelength of 630 nm. Dose enhancement was measured for 5 nm and 50 nm monodispersed gold nanoparticles, 5–50 nm polydispersed bismuth nanoparticles, and 80 nm monodispersed bismuth nanoparticles at concentrations from 0.25 mM to 2 mM. The dose enhancement was highest for the 95.3 keV mean energy synchrotron beam (16–32%) followed by the 150 kVp superficial beam (12–21%) then the 6 MV beam (2–5%). The bismuth nanoparticle-loaded dosimeters produced a larger dose enhancement than the gold nanoparticle-loaded dosimeters in the synchrotron beam for the same concentration. For the superficial and megavoltage beams the dose enhancement was similar for both species of nanoparticles. The dose enhancement increased with nanoparticle concentration in the dosimeters; however, there was no observed nanoparticle size dependence on the dose enhancement.

2

Martelli, Stefano, and James C. L. Chow. "Dose Enhancement for the Flattening-Filter-Free and Flattening-Filter Photon Beams in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Study." Nanomaterials 10, no. 4 (March 29, 2020): 637. http://dx.doi.org/10.3390/nano10040637.

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Monte Carlo simulations were used to predict the dose enhancement ratio (DER) using the flattening-filter-free (FFF) and flattening-filter (FF) photon beams in prostate nanoparticle-enhanced radiotherapy, with multiple variables such as nanoparticle material, nanoparticle concentration, prostate size, pelvic size, and photon beam energy. A phantom mimicking the patient’s pelvis with various prostate and pelvic sizes was used. Macroscopic Monte Carlo simulation using the EGSnrc code was used to predict the dose at the prostate or target using the 6 MV FFF, 6 MV FF, 10 MV FFF, and 10 MV FF photon beams produced by a Varian TrueBeam linear accelerator (Varian Medical System, Palo Alto, CA, USA). Nanoparticle materials of gold, platinum, iodine, silver, and iron oxide with concentration varying in the range of 3–40 mg/ml were used in simulations. Moreover, the prostate and pelvic size were varied from 2.5 to 5.5 cm and 20 to 30 cm, respectively. The DER was defined as the ratio of the target dose with nanoparticle addition to the target dose without nanoparticle addition in the simulation. From the Monte Carlo results of DER, the best nanoparticle material with the highest DER was gold, based on all the nanoparticle concentrations and photon beams. Smaller prostate size, smaller pelvic size, and a higher nanoparticle concentration showed better DER results. When comparing energies, the 6 MV beams always had the greater enhancement ratio. In addition, the FFF photon beams always had a better DER when compared to the FF beams. It is concluded that gold nanoparticles were the most effective material in nanoparticle-enhanced radiotherapy. Moreover, lower photon beam energy (6 MV), FFF photon beam, higher nanoparticle concentration, smaller pelvic size, and smaller prostate size would all increase the DER in prostate nanoparticle-enhanced radiotherapy.

3

Abdulle, Aniza, and James C. L. Chow. "Contrast Enhancement for Portal Imaging in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Evaluation Using Flattening-Filter-Free Photon Beams." Nanomaterials 9, no. 7 (June 26, 2019): 920. http://dx.doi.org/10.3390/nano9070920.

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Our team evaluated contrast enhancement for portal imaging using Monte Carlo simulation in nanoparticle-enhanced radiotherapy. Dependencies of percentage contrast enhancement on flattening-filter (FF) and flattening-filter-free (FFF) photon beams were determined by varying the nanoparticle material (gold, platinum, iodine, silver, iron oxide), nanoparticle concentration (3–40 mg/mL) and photon beam energy (6 and 10 MV). Phase-space files and energy spectra of the 6 MV FF, 6 MV FFF, 10 MV FF and 10 MV FFF photon beams were generated based on a Varian TrueBeam linear accelerator. We found that gold and platinum nanoparticles (NP) produced the highest contrast enhancement for portal imaging, compared to other NP with lower atomic numbers. The maximum percentage contrast enhancements for the gold and platinum NP were 18.9% and 18.5% with a concentration equal to 40 mg/mL. The contrast enhancement was also found to increase with the nanoparticle concentration. The maximum rate of increase of contrast enhancement for the gold NP was equal to 0.29%/mg/mL. Using the 6 MV photon beams, the maximum contrast enhancements for the gold NP were 79% (FF) and 78% (FFF) higher than those using the 10 MV beams. For the FFF beams, the maximum contrast enhancements for the gold NP were 53.6% (6 MV) and 53.8% (10 MV) higher than those using the FF beams. It is concluded that contrast enhancement for portal imaging can be increased when a higher atomic number of NP, higher nanoparticle concentration, lower photon beam energy and no flattening filter of photon beam are used in nanoparticle-enhanced radiotherapy.

4

Chow, James C. L., and Sama Jubran. "Depth Dose Enhancement in Orthovoltage Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Study." Micromachines 14, no. 6 (June 10, 2023): 1230. http://dx.doi.org/10.3390/mi14061230.

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Background: This study was to examine the depth dose enhancement in orthovoltage nanoparticle-enhanced radiotherapy for skin treatment by investigating the impact of various photon beam energies, nanoparticle materials, and nanoparticle concentrations. Methods: A water phantom was utilized, and different nanoparticle materials (gold, platinum, iodine, silver, iron oxide) were added to determine the depth doses through Monte Carlo simulation. The clinical 105 kVp and 220 kVp photon beams were used to compute the depth doses of the phantom at different nanoparticle concentrations (ranging from 3 mg/mL to 40 mg/mL). The dose enhancement ratio (DER), which represents the ratio of the dose with nanoparticles to the dose without nanoparticles at the same depth in the phantom, was calculated to determine the dose enhancement. Results: The study found that gold nanoparticles outperformed the other nanoparticle materials, with a maximum DER value of 3.77 at a concentration of 40 mg/mL. Iron oxide nanoparticles exhibited the lowest DER value, equal to 1, when compared to other nanoparticles. Additionally, the DER value increased with higher nanoparticle concentrations and lower photon beam energy. Conclusions: It is concluded in this study that gold nanoparticles are the most effective in enhancing the depth dose in orthovoltage nanoparticle-enhanced skin therapy. Furthermore, the results suggest that increasing nanoparticle concentration and decreasing photon beam energy lead to increased dose enhancement.

5

Rasoolpoor, M., R. Ansari, and MK Hassanzadeh-Aghdam. "Multiscale analysis of the low-velocity impact behavior of ceramic nanoparticle-reinforced metal matrix nanocomposite beams by micromechanics and finite element approaches." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 12 (July 15, 2019): 2419–32. http://dx.doi.org/10.1177/1464420719861993.

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An efficient multiscale analysis is proposed to investigate the dynamic behavior of metal matrix nanocomposite beams reinforced by SiC nanoparticles under low-velocity impact loads. First, an analytical micromechanics model is developed to obtain the effective elastic properties of ceramic nanoparticle-reinforced metal matrix nanocomposite, and then the finite element method is used to predict the dynamic response of beams made of this nanocomposite material. Two important microstructural features, including size effect and agglomeration of nanoscale particles, are incorporated into the micromechanical analysis. The present simulation results for the elastic modulus and low-velocity impact response show good agreement with previously published results. The effects of volume percent, diameter and dispersion type of ceramic nanoparticles, geometrical features and boundary conditions of nanostructure, velocity and size of projectile on the contact force, and center deflection time histories of metal matrix nanocomposite beams are extensively examined. Analysis shows that homogenously distributed SiC nanoparticles into the metal matrix nanocomposites can obviously increase the nanostructure/projectile contact force and decrease both the beam center deflection and impact duration which is due to the enhancement of elastic properties. However, the ceramic nanoparticle agglomeration has an effect on the decrease of contact force and the increase of both the center deflection and impact duration. Also, it is concluded that decreasing nanoparticle size can increase the contact force and decrease the beam center deflection.

6

Huynh, Ngoc Han, and James C. L. Chow. "DNA Dosimetry with Gold Nanoparticle Irradiated by Proton Beams: A Monte Carlo Study on Dose Enhancement." Applied Sciences 11, no. 22 (November 17, 2021): 10856. http://dx.doi.org/10.3390/app112210856.

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Heavy atom nanoparticles, such as gold nanoparticles, are proven effective radiosensitizers in radiotherapy to enhance the dose delivery for cancer treatment. This study investigated the effectiveness of cancer cell killing, involving gold nanoparticle in proton radiation, by changing the nanoparticle size, proton beam energy, and distance between the nanoparticle and DNA. Monte Carlo (MC) simulation (Geant4-DNA code) was used to determine the dose enhancement in terms of dose enhancement ratio (DER), when a gold nanoparticle is present with the DNA. With varying nanoparticle size (radius = 15–50 nm), distance between the gold nanoparticle and DNA (30–130 nm), as well as proton beam energy (0.5–25 MeV) based on the simulation model, our results showed that the DER value increases with a decrease of distance between the gold nanoparticle and DNA and a decrease of proton beam energy. The maximum DER (1.83) is achieved with a 25 nm-radius gold nanoparticle, irradiated by a 0.5 MeV proton beam and 30 nm away from the DNA.

7

Gatsa, Oleksandr, Shabbir Tahir, Miroslava Flimelová, Farbod Riahi, Carlos Doñate-Buendia, Bilal Gökce, and Alexander V. Bulgakov. "Unveiling Fundamentals of Multi-Beam Pulsed Laser Ablation in Liquids toward Scaling up Nanoparticle Production." Nanomaterials 14, no. 4 (February 16, 2024): 365. http://dx.doi.org/10.3390/nano14040365.

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Pulsed laser ablation in liquids (PLAL) is a versatile technique to produce high-purity colloidal nanoparticles. Despite considerable recent progress in increasing the productivity of the technique, there is still significant demand for a practical, cost-effective method for upscaling PLAL synthesis. Here we employ and unveil the fundamentals of multi-beam (MB) PLAL. The MB-PLAL upscaling approach can bypass the cavitation bubble, the main limiting factor of PLAL efficiency, by splitting the laser beam into several beams using static diffractive optical elements (DOEs). A multimetallic high-entropy alloy CrFeCoNiMn was used as a model material and the productivity of its nanoparticles in the MB-PLAL setup was investigated and compared with that in the standard single-beam PLAL. We demonstrate that the proposed multi-beam method helps to bypass the cavitation bubble both temporally (lower pulse repetition rates can be used while keeping the optimum processing fluence) and spatially (lower beam scanning speeds are needed) and thus dramatically increases the nanoparticle yield. Time-resolved imaging of the cavitation bubble was performed to correlate the observed production efficiencies with the bubble bypassing. The results suggest that nanoparticle PLAL productivity at the level of g/h can be achieved by the proposed multi-beam strategy using compact kW-class lasers and simple inexpensive scanning systems.

8

Fang, Jingyue, Xinxing Li, Wenke Xie, and Kehui Sun. "A Novel Fabrication of Single Electron Transistor from Patterned Gold Nanoparticle Array Template-Prepared by Polystyrene Nanospheres." Nanomaterials 12, no. 18 (September 7, 2022): 3102. http://dx.doi.org/10.3390/nano12183102.

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In this paper, polystyrene microspheres were firstly prepared by seeded emulsion polymerization, and the uniform monolayer of polystyrene microspheres was prepared on the substrate by the dipping method. Then, polystyrene monolayer film was used as a mask and a low dimensional array structure of gold was prepared by bottom-up self-assembly process. After that, the method of solution etching and annealing was used, and the gold nanoparticle array was post-processed. As a result, gold nanoparticles were recrystallized, with an average diameter of about 50 nm. Subsequently, the semiconductor process was adopted, with focused ion beams induced deposition and electron beam evaporation, and single electron transistors were fabricated, based on self-assembled gold nanoparticles. Finally, the devices were fixed in a liquid helium cryostat and Coulomb blockade was observed at 320 mK. It is a novel fabrication of a single electron transistor based on gold nanoparticle array template and prepared with polystyrene nanospheres.

9

Srinivasan, K., and E. James Jabaseelan Samuel. "Effective atomic number and photon buildup factor of bismuth doped tissue for photon and particles beam interaction." Polish Journal of Medical Physics and Engineering 28, no. 1 (March 1, 2022): 37–51. http://dx.doi.org/10.2478/pjmpe-2022-0005.

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Abstract Introduction: The doping of high Z nanoparticles into the tumor tissue increases the therapeutic efficiency of radiotherapy called nanoparticle enhanced radiotherapy (NERT). In the present study, we are identifying the effective types of radiation and effective doping concentration of bismuth radiosensitizer for NERT application by analyzing effective atomic number (Zeff) and photon buildup factor (PBF) of bismuth (Bi) doped soft tissue for the photon, electron, proton, alpha particle, and carbon ion interactions. Material and methods: The direct method was used for the calculation of Zeff for photon and electron beams (10 keV-30 MeV). The phy-X/ZeXTRa software was utilized for the particle beams such as proton, alpha particle, and carbon ions (1-15 MeV). Bismuth doping concentrations of 5, 10, 15, 20, 25 and 30 mg/g were considered. The PBF was calculated over 15 keV-15 MeV energies using phy-X/PSD software. Results: The low energy photon (<100 keV) interaction with a higher concentration of Bi dopped tissue gives the higher values of Zeff. The Zeff increased with the doping concentration of bismuth for all types of radiation. The Zeff was dependent on the type of radiation, the energy of radiation, and the concentration of Bi doping. The particle beams such as electron, proton, alpha particle, and carbon ion interaction gives the less values of Zeff has compared to photon beam interaction. On the other hand, the photon buildup factor values were decreased while increasing the Bi doping concentration. Conclusions: According to Zeff and PBF, the low energy photon and higher concentration of radiosensitizer are the most effective for nanoparticle enhanced radiotherapy application. Based on the calculated values of Zeff, the particle beams such as electron, proton, alpha particle, and carbon ions were less effective for NERT application. The presented values of Zeff and PBF are useful for the radiation dosimetry in NERT.

10

Kawaguchi, Haruki, Kei Umesato, Kanta Takahashi, Keisaku Yamane, Ryuji Morita, Ken-ichi Yuyama, Satoyuki Kawano, Katsuhiko Miyamoto, Michinari Kohri, and Takashige Omatsu. "Generation of hexagonal close-packed ring-shaped structures using an optical vortex." Nanophotonics 11, no. 4 (October 20, 2021): 855–64. http://dx.doi.org/10.1515/nanoph-2021-0437.

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Abstract An optical vortex possesses a ring-shaped spatial profile and orbital angular momentum (OAM) owing to its helical wavefront. This form of structured light has garnered significant attention in recent years, and it has enabled new investigations in fundamental physics and applications. One such exciting application is laser-based material transfer for nano-/micro-fabrication. In this work, we demonstrate the application of a single-pulse optical vortex laser beam for direct printing of ring-shaped structures composed of hexagonal close-packed, mono-/multi-layered nanoparticles which exhibit ‘structural color’. We compare and contrast the interaction of the vortex beam with both dielectric and metallic nanoparticles and offer physical insight into how the OAM of vortex beams interacts with matter. The demonstrated technique holds promise for not only photonic-based nano-/micro-fabrication, but also as a means of sorting particles on the nanoscale, a technology which we term ‘optical vortex nanoparticle sorting’.

11

Mesbahi, Asghar, Elham Mansouri, and Mohammad Mohammadzadeh. "Nanoscale dosimetric consequences around bismuth, gold, gadolinium, hafnium, and iridium nanoparticles irradiated by low energy photons." Polish Journal of Medical Physics and Engineering 26, no. 4 (December 1, 2020): 225–34. http://dx.doi.org/10.2478/pjmpe-2020-0027.

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Abstract In the current study, nanoscale physical dose distributions around five potential nanoparticles were compared. Five potential nanoparticles including bismuth, gold, gadolinium, hafnium, and iridium nanoparticles in the form of a sphere with a diameter of 50 nm were simulated in a water medium. The MCNPX (2.7.0) Monte Carlo code with updated libraries was used for calculations of electron dose deposition and electron flux in water from 25 nm up to 4000 nm with a step of 25 nm. Also, secondary electron spectra after irradiation of nanoparticles with mono-energetic photons with energies of 30, 60, 100 keV were derived. The nano-scale distance-dose curves showed a very steep gradient with distance from nanoparticle surface up to 60 nm and after this point, a gradual decrease was seen. The dose deposition characteristics in the nano-scale were dependent on the type of nanoparticle as well as photon energy. Our results concluded that for each photon energy in the energy range of 30-100 keV, a suitable nanoparticle can be selected to boost the effect of energy deposition by low energy photon beams used in brachytherapy.

12

Dine Elhennani, Soumia, Zouaoui R. Harrat, Mohammed Chatbi, Asma Belbachir, Baghdad Krour, Ercan Işık, Ehsan Harirchian, Mohamed Bouremana, and Mohamed Bachir Bouiadjra. "Buckling and Free Vibration Analyses of Various Nanoparticle Reinforced Concrete Beams Resting on Multi-Parameter Elastic Foundations." Materials 16, no. 17 (August 27, 2023): 5865. http://dx.doi.org/10.3390/ma16175865.

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Given their considerable specific surface area and amorphous characteristics, nanoparticles exhibit excellent pozzolanic activity, and when undergoing a reaction with calcium hydroxide, this leads to the generation of a denser matrix by promoting the formation of a greater amount of C-S-H gel, thereby enhancing the strength and durability of the concrete and fortifying the overall structure. Indeed, the present study investigates a comparative study of the buckling and free vibration analyses of concrete beams reinforced with various types of nanoparticles. For its simplicity and accuracy, a higher-order shear deformation theory will be used to analytically model the reinforced concrete beam. Furthermore, the powerful Eshelby’s model is used to derive the equivalent nanocomposite properties. The soil medium is simulated with Pasternak elastic foundation, including a shear layer, and Winkler’s spring, interlinked with a Kerr foundation. The motion equations are derived using Hamilton’s principle. Moreover, based on Navier’s analytical methods, the closed-form solutions of simply supported beams have been obtained. Different parameters, such as type and volume percent of nanoparticles, geometrical parameters, choice of theory and soil medium, on the buckling and dynamic behavior of the beam, are exercised and shown. The major findings of this work indicate that the use of nanoparticles in concretes increases better mechanical resistance and amplifies the natural frequencies. In addition, the elastic foundation has a significant impact on the buckling and vibration performances of concrete beams.

13

Passig, Johannes, Karl-Heinz Meiwes-Broer, and Josef Tiggesbäumker. "Collimation of metal nanoparticle beams using aerodynamic lenses." Review of Scientific Instruments 77, no. 9 (September 2006): 093304. http://dx.doi.org/10.1063/1.2349619.

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14

Elnaggar, A. M., A. Albassam, K. Oźga, J. Jędryka, M. Szota, and G. Myronchuk. "Photoinduced Operation by Absorption of the Chalcogenide Nanocrystallite Containing Solar Cells." Archives of Metallurgy and Materials 61, no. 4 (December 1, 2016): 1953–56. http://dx.doi.org/10.1515/amm-2016-0314.

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Abstract It is shown that for the solar cells containing chalcogenide nanocrystallites using external laser light, one can achieve some enhancement of the photovoltaic efficiency. Photoinduced treatment was carried out using two beams of splitted Er: glass laser operating at 1.54 μm. The light of the laser was incident at different angles and the angles between the beams also were varied. Also, the studies of nanocomposite effective structures have shown enhancement of effective nanocrystalline sizes during the laser treatment. Nanocrystallites of CuInS2 and CuZnSnS4 (CZTS) were used as chalcogenide materials. The optimization of the laser beam intensities and nanoparticle sizes were explored.

15

Balbuena Ortega, Argelia Balbuena, Felix E. Torres-González, Valentin López López Gayou, Raul Delgado Delgado Macuil, Gaetano Assanto, and Karen Volke-Sepulveda. "Light Confinement with Structured Beams in Gold Nanoparticle Suspensions." Photonics 8, no. 6 (June 15, 2021): 221. http://dx.doi.org/10.3390/photonics8060221.

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We carry out an experimental campaign to investigate the nonlinear self-defocusing propagation of singular light beams with various complex structures of phase and intensity in a colloidal suspension of gold nanoparticles with a plasmonic resonance near the laser wavelength (532nm). Studying optical vortices embedded in Gaussian beams, Bessel vortices and Bessel-cosine (necklace) beams, we gather evidence that while intense vortices turn into two-dimensional dark solitons, all structured wavepackets are able to guide a weak Gaussian probe of different wavelength (632.8 nm) along the dark core. The probe confinement also depends on the topological charge of the singular pump.

16

Petrov, N. I. "Thin-Film Frustrated Total Internal Reflection Filter with Plasmonic Nanoparticle Inclusions in the Layers." Journal of Physics: Conference Series 2015, no. 1 (November 1, 2021): 012109. http://dx.doi.org/10.1088/1742-6596/2015/1/012109.

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Abstract The influence of plasmonic nanoparticles embedded in the central and side layers of the frustrated total internal reflection filter on the resonant transmission of light is analyzed. It is shown that the frequency dispersion causes the splitting of the filter bandwidth and the angular splitting of the incident beam into several output beams.

17

Sheeraz, Zaynah, and James C. L. Chow. "Evaluation of dose enhancement with gold nanoparticles in kilovoltage radiotherapy using the new EGS geometry library in Monte Carlo simulation." AIMS Biophysics 8, no. 4 (2021): 337–45. http://dx.doi.org/10.3934/biophy.2021027.

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<abstract><sec> <title>Purpose</title> <p>This study compared the dose enhancement predicted in kilovoltage gold nanoparticle-enhanced radiotherapy using the newly developed EGS lattice and the typical gold-water mixture method in Monte Carlo simulation. This new method considered the gold nanoparticle-added volume consisting of solid nanoparticles instead of a gold-water mixture. In addition, this particle method is more realistic in simulation.</p> </sec><sec> <title>Methods</title> <p>A heterogeneous phantom containing bone and water was irradiated by the 105 and 220 kVp x-ray beams. Gold nanoparticles were added to the tumour volume with concentration varying from 3–40 mg/mL in the phantom. The dose enhancement ratio (DER), defined as the ratio of dose at the tumour with and without adding gold nanoparticles, was calculated by the gold-water mixture and particle method using Monte Carlo simulation for comparison.</p> </sec><sec> <title>Results</title> <p>It is found that the DER was 1.44–4.71 (105 kVp) and 1.27–2.43 (220 kVp) for the gold nanoparticle concentration range of 3–40 mg/mL, when they were calculated by the gold-water mixture method. The DER was slightly larger and equal to 1.47–4.84 (105 kVp) and 1.29–2.5 (220 kVp) for the same concentration range, when the particle method was used. Moreover, the DER predicted by both methods increased with an increase of nanoparticle concentration, and a decrease of x-ray beam energy.</p> </sec><sec> <title>Conclusion</title> <p>The deviation of DER determined by the particle and gold-water mixture method was insignificant when considering the uncertainty in the calculation of DER (2%) in the nanoparticle concentration range of 3–40 mg/mL. It is therefore concluded that the gold-water mixture method could predict the dose enhancement as accurate as the newly developed particle method.</p> </sec></abstract>

18

Sheeraz, Zaynah, and James C. L. Chow. "Evaluation of dose enhancement with gold nanoparticles in kilovoltage radiotherapy using the new EGS geometry library in Monte Carlo simulation." AIMS Biophysics 8, no. 4 (2021): 337–45. http://dx.doi.org/10.3934/biophy.2021027.

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<abstract><sec> <title>Purpose</title> <p>This study compared the dose enhancement predicted in kilovoltage gold nanoparticle-enhanced radiotherapy using the newly developed EGS lattice and the typical gold-water mixture method in Monte Carlo simulation. This new method considered the gold nanoparticle-added volume consisting of solid nanoparticles instead of a gold-water mixture. In addition, this particle method is more realistic in simulation.</p> </sec><sec> <title>Methods</title> <p>A heterogeneous phantom containing bone and water was irradiated by the 105 and 220 kVp x-ray beams. Gold nanoparticles were added to the tumour volume with concentration varying from 3–40 mg/mL in the phantom. The dose enhancement ratio (DER), defined as the ratio of dose at the tumour with and without adding gold nanoparticles, was calculated by the gold-water mixture and particle method using Monte Carlo simulation for comparison.</p> </sec><sec> <title>Results</title> <p>It is found that the DER was 1.44–4.71 (105 kVp) and 1.27–2.43 (220 kVp) for the gold nanoparticle concentration range of 3–40 mg/mL, when they were calculated by the gold-water mixture method. The DER was slightly larger and equal to 1.47–4.84 (105 kVp) and 1.29–2.5 (220 kVp) for the same concentration range, when the particle method was used. Moreover, the DER predicted by both methods increased with an increase of nanoparticle concentration, and a decrease of x-ray beam energy.</p> </sec><sec> <title>Conclusion</title> <p>The deviation of DER determined by the particle and gold-water mixture method was insignificant when considering the uncertainty in the calculation of DER (2%) in the nanoparticle concentration range of 3–40 mg/mL. It is therefore concluded that the gold-water mixture method could predict the dose enhancement as accurate as the newly developed particle method.</p> </sec></abstract>

19

Yang, Zhuo, and Dengfeng Kuang. "Visible-broadband Localized Vector Vortex Beam Generator with a Multi-structure-composited Meta-surface." Nanomaterials 9, no. 2 (January 29, 2019): 166. http://dx.doi.org/10.3390/nano9020166.

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We demonstrate a vortex beam generator meta-surface that consists of silver structures and graphene layers. The miniature material is just a few microns in size and the working part is only a few hundred nanometers thick. With the incidence of the linearly polarized beam, the meta-surface generates high-localized vector vortex beam with a high proportion of the longitudinal component. Being compared with the constituent part of the meta-surface, the multi-structure-combined meta-surface increases the localization by 250% and the longitudinal component proportion by 200%. Moreover, the above artificial material can generate vortex beams in broadband within the visible light range. These novel optical properties have the potential to improve the precision and sensitivity of nanoparticle manipulation. The study serves as a foundation in optical miniaturization and integration, nanoparticle manipulation, high-efficiency optical and quantum communication, and light-driven micro-tools.

20

Reiger, Elisabeth, Lucia Hackermüller, Martin Berninger, and Markus Arndt. "Exploration of gold nanoparticle beams for matter wave interferometry." Optics Communications 264, no. 2 (August 2006): 326–32. http://dx.doi.org/10.1016/j.optcom.2006.02.060.

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21

Chow, James C. L., and Christine A. Santiago. "DNA Damage of Iron-Gold Nanoparticle Heterojunction Irradiated by kV Photon Beams: A Monte Carlo Study." Applied Sciences 13, no. 15 (August 3, 2023): 8942. http://dx.doi.org/10.3390/app13158942.

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This study aims to evaluate the dependence of DNA damage on the proportion of iron and gold in iron-gold nanoparticle heterojunctions using Monte Carlo simulations. The simulation setup included a spherical nanoparticle with varying percentages of iron and gold, irradiated by photon beams of different energies (50–150 keV). The Geant4-DNA Monte Carlo code was utilized for the accurate tracking of radiation transport. The results reveal that DNA damage increases with a higher percentage of gold volume in the heterojunction, primarily due to photoelectric enhancement. Furthermore, a lower photon beam energy of 50 keV induces greater DNA damage compared to energies of 100 keV and 150 keV. The findings suggest that for effective cancer cell eradication through DNA damage, the gold volume should be equal to or greater than 50% in the iron-gold nanoparticle heterojunction. In conclusion, the findings from this study will shed light on the potential of iron-gold nanoparticle heterojunctions in enhancing radiotherapy outcomes. The investigation of DNA damage resulting from the combination of contrast agents and radiosensitizers is crucial for advancing cancer research and treatment. The knowledge gained from this research will aid in the development of personalized and effective radiotherapy approaches, ultimately improving patient outcomes in cancer treatment.

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Shi, W., J. Zou, K. Y. Lee, and X. F. Li. "Size-dependent resonance frequencies of cantilevered and bridged nanosensors." Modern Physics Letters B 32, no. 07 (March 5, 2018): 1850095. http://dx.doi.org/10.1142/s0217984918500951.

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This paper studies transverse vibration of nanoscale cantilevered and bridged sensors carrying a nanoparticle. The nanoscale sensors are modelled as Euler–Bernoulli beams with surface effect and nanoparticle as a concentrated mass. Frequency equations of cantilevered and bridged beam-mass system are derived and exact resonance frequencies are calculated. An alternative Fredholm integral equation method is used to obtain an approximate explicit expression for the fundamental frequency for both cases. A comparison between the approximate and analytical results is made and the approximation accuracy is satisfactory. The influences of the residual surface stress, surface elasticity, and attached mass on the resonance frequencies and mode shapes are discussed. These results are useful to illustrate the surface phenomena and are helpful to design micro-/nano-mechanical sensors.

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Pathreeker, Shreyas, Fu-Hao Chen, Saeid Biria, and Ian D. Hosein. "Observation of intensity dependent phase-separation in photoreactive monomer–nanoparticle formulations under non-uniform visible light irradiation." Soft Matter 16, no. 31 (2020): 7256–69. http://dx.doi.org/10.1039/d0sm00922a.

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Martínez-Rovira, I., O. Seksek, I. Dokic, S. Brons, A. Abdollahi, and I. Yousef. "Study of the intracellular nanoparticle-based radiosensitization mechanisms in F98 glioma cells treated with charged particle therapy through synchrotron-based infrared microspectroscopy." Analyst 145, no. 6 (2020): 2345–56. http://dx.doi.org/10.1039/c9an02350j.

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GAMERO-CASTAÑO, MANUEL. "The structure of electrospray beams in vacuum." Journal of Fluid Mechanics 604 (May 14, 2008): 339–68. http://dx.doi.org/10.1017/s0022112008001316.

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Electrospray atomization of liquids in the cone-jet mode generates narrow droplet distributions with average diameters as small as a few nanometres. This ability is important for technologies such as colloid thrusters, nanoparticle generation and ion beam processes, and the optimization of these applications requires an understanding of the physics and structure of the associated beams. This paper presents a detailed experimental characterization of electrosprays in vacuum and formulates an analytical model of the beam. A key feature of our model is the use of a simplified expression for the electric field induced by the space charge. This simplification leads to a time-independent Eulerian formulation compatible with an analytical solution, in contrast to the direct simulation of a multitude of droplets which must be simultaneously tracked to account for Coulombic interactions. We find that the beams open up in an initial region relatively insensitive to the external electrodes, a process dominated by the electric repulsion between droplets and the initial droplet inertia. Although the external electric field modifies the trajectories of the droplets downstream of this initial region, the effect is moderate in our typical electrospray source and the analytical solution in the space charge region explains well the far-field beam structure observed experimentally. We also describe a numerical scheme that implements the full effect of the external electric field and provides a more accurate solution.

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Othman, Zamrood A., Yousif M. Hassan, and Abdulkarim Y. Karim. "Enhancement of skin tumor laser hyperthermia with Ytterbium nanoparticles: numerical simulation." Biomedical Materials 19, no. 3 (March 28, 2024): 035021. http://dx.doi.org/10.1088/1748-605x/ad3535.

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Abstract Laser hyperthermia therapy (HT) has emerged as a well-established method for treating cancer, yet it poses unique challenges in comprehending heat transfer dynamics within both healthy and cancerous tissues due to their intricate nature. This study investigates laser HT therapy as a promising avenue for addressing skin cancer. Employing two distinct near-infrared (NIR) laser beams at 980 nm, we analyze temperature variations within tumors, employing Pennes’ bioheat transfer equation as our fundamental investigative framework. Furthermore, our study delves into the influence of Ytterbium nanoparticles (YbNPs) on predicting temperature distributions in healthy and cancerous skin tissues. Our findings reveal that the application of YbNPs using a Gaussian beam shape results in a notable maximum temperature increase of 5 °C within the tumor compared to nanoparticle-free heating. Similarly, utilizing a flat top beam alongside YbNPs induces a temperature rise of 3 °C. While this research provides valuable insights into utilizing YbNPs with a Gaussian laser beam configuration for skin cancer treatment, a more thorough understanding could be attained through additional details on experimental parameters such as setup, exposure duration, and specific implications for skin cancer therapy.

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Chow, James C. L. "Depth Dose Enhancement on Flattening-Filter-Free Photon Beam: A Monte Carlo Study in Nanoparticle-Enhanced Radiotherapy." Applied Sciences 10, no. 20 (October 11, 2020): 7052. http://dx.doi.org/10.3390/app10207052.

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The aim of this study is to investigate the variations of depth dose enhancement (DDE) on different nanoparticle (NP) variables, when using the flattening-filter-free (FFF) photon beam in nanoparticle-enhanced radiotherapy. Monte Carlo simulation under a macroscopic approach was used to determine the DDE ratio (DDER) with variables of NP material (gold (Au) and iron (III) oxide (Fe2O3)), NP concentration (3–40 mg/mL) and photon beam (10 MV flattening-filter (FF) and 10 MV FFF). It is found that Au NPs had a higher DDER than Fe2O3 NPs, when the depths were shallower than 6 and 8 cm for the 10 MV FF and 10 MV FFF photon beams, respectively. However, in a deeper depth range of 10–20 cm, DDER for the Au NPs was lower than Fe2O3 NPs mainly due to the beam attenuation and photon energy distribution. It is concluded that DDER for the Au NPs and Fe2O3 NPs decreased with an increase of depth in the range of 10–20 cm, with rate of decrease depending on the NP material, NP concentration and the use of FF in the photon beam.

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Zhao, Xiaomin, Chenglin Du, Rong Leng, Li Li, Weiwei Luo, Wei Wu, Yinxiao Xiang, et al. "Linewidth narrowing of aluminum breathing plasmon resonances in Bragg grating decorated nanodisks." Nanoscale Advances 3, no. 14 (2021): 4286–91. http://dx.doi.org/10.1039/d1na00184a.

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The profound linewidth narrowing of the plasmon resonance of an individual Al nanoparticle through Bragg grating decoration was demonstrated with electron beams, suggesting a feasible approach to realize Al plasmon resonance with a higher quality factor.

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Wang, Jiayue, Kevin B. Woller, and Bilge Yildiz. "Ion Beam as an External and Dynamic Metal Reservoir to Induce Nanoparticle Exsolution in Oxides." ECS Transactions 111, no. 6 (May 19, 2023): 809–16. http://dx.doi.org/10.1149/11106.0809ecst.

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Nanoparticle exsolution is a recently developed method to produce oxide-supported metal nanoparticles via phase precipitation. It has attracted significant attention in the field of solid oxide fuel cells and electrolyzers (SOFC/SOEC) due to its potential for producing active and nanostructured electrodes. However, conventional exsolution methods face challenges in reaching the solubility limit of metal ions in the oxide matrix. To overcome this issue, here we propose a new approach to induce exsolution by using ion beams as an external and dynamic metal reservoir. We demonstrate the effectiveness of this method by using thin-film Zr0.5Ce0.5O2 (CZO) as a model system. Through ion irradiation experiments, 10 keV Ni ions were implanted into the near-surface regions of CZO films, and then exsolved as nanoparticles on the surface. This research offers a promising new avenue for developing next-generation SOFC/SOEC electrode materials using irradiation-tailored exsolution.

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Chow, James C. L., Michael K. K. Leung, and David A. Jaffray. "Monte Carlo simulation on a gold nanoparticle irradiated by electron beams." Physics in Medicine and Biology 57, no. 11 (May 9, 2012): 3323–31. http://dx.doi.org/10.1088/0031-9155/57/11/3323.

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31

Abdulwaahb, Hala Mahmood, Bassam G. Rasheed, and Hanadi H. Altawil. "Deposition of MgO Nanoparticles by Laser Pyrolysis." Al-Nahrain Journal for Engineering Sciences 25, no. 1 (April 3, 2022): 20–27. http://dx.doi.org/10.29194/njes.25010020.

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Magnesium oxide nanoparticles were deposited by laser pyrolysis process. Three types of lasers were employed CW CO2, Q-switched Nd-YAG (short pulses) and long pulses Nd-YAG lasers. The size and density of nanoparticles vary with laser energy, power, pulse duration and the scanning speed of the laser. In this method, MgO nanoparticles were deposited by a laser beam on a quartz substrate from aqueous solution of magnesium nitrate. AFM images reveal formation of small nanoparticle size of 24.5 nm with surface roughness 6.97nm by Q-switched Nd-YAG laser (10 ns) when the energy was 1J. While for CO2 laser, the smallest size was 18.8 nm at 0.4mm/s scanning speed with surface roughness 5.21nm at the same scanning speed. Moreover, long Nd-YAG pulses laser produces relatively larger average size of 37.5nm at 0.8ms pulse duration. The absorption spectra from UV-Visible spectroscopy were also conducted. The best absorption intensity was obtained at a wavelength ranging between 420-430 nm for both lasers. Finally, Thermal analysis using COMSOL Multiphysics software for the deposition process reveals that maximum temperature about 440Kfor Q-Switched Nd-YAG laser at 1J laser energy. While for RF CO2 laser, the maximum temperature obtained at 0.4mm/s scanning speed is 850K.This work provides a good knowledge for the deposition of nanoparticles using laser beams.

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Wang, Jiayue, Kevin B. Woller, and Bilge Yildiz. "Ion Beam as an External and Dynamic Metal Reservoir to Induce Nanoparticle Exsolution in Oxides." ECS Meeting Abstracts MA2023-01, no. 54 (August 28, 2023): 129. http://dx.doi.org/10.1149/ma2023-0154129mtgabs.

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A central theme in solid oxide fuel cells (SOFC) and electrolyzers (SOEC) is to design stable and catalytically active solid/gas interfaces toward desired reactions. A recent advance in this regard is to synthesize nanoparticles decorated electrodes in a process termed “exsolution”. Exsolution generates stable and catalytically active metal nanoparticles via phase precipitation out of a host oxide. Unlike traditional nanoparticle infiltration techniques, the nanoparticle catalysts from exsolution are anchored in the parent oxide. This strong metal-oxide interaction makes the exsolved nanoparticles more resistant against particle agglomeration as compared to the infiltrated ones. In addition, the exsolved particles also open up the possibility of regeneration of catalysts. To date, the concept of exsolution has been successfully applied to a number of applications including SOFC/SOEC, ceramic membrane reactors, chemical looping combustion, and (electro)catalysis. As the exsolution process starts with a solid-solution that contains the to-be-exsolved transition metal ions, this method is often limited by the intrinsic solubility limit of the host oxide. Here, we propose that ion beam irradiation to be a unique tool to promote exsolution as it can introduce defects and dopants into the host oxides and at concentrations higher than thermodynamic limits. Moreover, due to the surface sputtering effect, ion beam irradiation can modulate the surface morphology, creating novel nanostructures. To demonstrate this approach, we chose thin-film perovskite SrTi0.65Fe0.35O3 (STF) and fluorite Ce0.5Zr0.5O2 (CZO) as model systems, both of which are promising materials in SOFC and SOEC. We modulated metal exsolution in both materials with in-situ 10-150 keV Ni irradiation at 800 °C in vacuum. Ni irradiation on STF controllably changed the exsolved particle composition from unitary Fe to bimetallic Fe-Ni. Moreover, it also reduced the particle size down to sub-2 nm, which outperforms other tuning methods thus far in the literature. As a result, the irradiation-modified STF demonstrated superior catalytic activity toward room-temperature oxygen evolution reactions (OER) than the conventional thermally exsolved STF. Regarding CZO, Ni irradiation also decorated the surface with well-dispersed nanoparticles, leading to enhanced high-temperature H2O splitting kinetics. The effective size and composition control over exsolution highlights the utility of metal ion beams in promoting and tailoring exsolved nanocatalysts for a broad range of applications in clean energy and fuel conversion. Figure 1

33

Liu, Yue, Li Chen, Chengxin Zhou, Kuangling Guo, Xiaoyi Wang, Yuhan Hong, Xiangbo Yang, Zhongchao Wei, and Hongzhan Liu. "Theoretical Study on Generation of Multidimensional Focused and Vector Vortex Beams via All-Dielectric Spin-Multiplexed Metasurface." Nanomaterials 12, no. 4 (February 9, 2022): 580. http://dx.doi.org/10.3390/nano12040580.

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The optical vortex (OV) beams characterized by orbital angular momentum (OAM) possess ubiquitous applications in optical communication and nanoparticle manipulation. Particularly, the vortex vector beams are important in classical physics and quantum sciences. Here, based on an all-dielectric transmission metasurface platform, we demonstrate a spin-multiplexed metadevice combining propagation phase and Pancharatnam–Berry (PB) phase. By utilizing a phase-only modulation method, the metadevice can generate spin-dependent and multidimensional focused optical vortex (FOV) under the orthogonally circularly polarized incident light, and it can successfully realize the multiplexed of the above-mentioned FOVs for linearly polarized light. Meanwhile, the superposition of multiple OAM states can also produce vector vortex beams with different modes. Additionally, the evolution process of the electric field intensity profile is presented after the resultant vector vortex beams through a horizontal linear polarization. This work paves an innovative way for generating structured beams, and it provides promising opportunities for advanced applications in optical data storage, optical micromanipulation, and data communication.

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Brivio, D., E. Sajo, and P. Zygmanski. "Gold nanoparticle detection and quantification in therapeutic MV beams via pair production." Physics in Medicine & Biology 66, no. 6 (March 8, 2021): 064004. http://dx.doi.org/10.1088/1361-6560/abd954.

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35

Gao, Wenpei, Peter Tieu, Christopher Addiego, Yanling Ma, Jianbo Wu, and Xiaoqing Pan. "Probing the dynamics of nanoparticle formation from a precursor at atomic resolution." Science Advances 5, no. 1 (January 2019): eaau9590. http://dx.doi.org/10.1126/sciadv.aau9590.

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Control of reduction kinetics and nucleation processes is key in materials synthesis. However, understanding of the reduction dynamics in the initial stages is limited by the difficulty of imaging chemical reactions at the atomic scale; the chemical precursors are prone to reduction by the electron beams needed to achieve atomic resolution. Here, we study the reduction of a solid-state Pt precursor compound in an aberration-corrected transmission electron microscope by combining low-dose and in situ imaging. The beam-sensitive Pt precursor, K2PtCl4, is imaged at atomic resolution, enabling determination of individual (K, Pt, Cl) atoms. The transformation to Pt nanoclusters is captured in real time, showing a three-stage reaction including the breaking of the ionic bond, formation of PtCl2, and the reduction of the dual-valent Pt to Pt metal. Deciphering the atomic-scale transformation of chemicals in real time using combined low-dose and in situ imaging brings new possibility to study reaction kinetics in general.

36

Fuentealba, Melani, Alejandro Ferreira, Apolo Salgado, Christopher Vergara, Sergio Díez, and Mauricio Santibáñez. "An Optimized Method for Evaluating the Potential Gd-Nanoparticle Dose Enhancement Produced by Electronic Brachytherapy." Nanomaterials 14, no. 5 (February 27, 2024): 430. http://dx.doi.org/10.3390/nano14050430.

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This work reports an optimized method to experimentally quantify the Gd-nanoparticle dose enhancement generated by electronic brachytherapy. The dose enhancement was evaluated considering energy beams of 50 kVp and 70 kVp, determining the Gd-nanoparticle concentration ranges that would optimize the process for each energy. The evaluation was performed using delaminated radiochromic films and a Poly(methyl methacrylate) (PMMA) phantom covered on one side by a thin 2.5 μm Mylar filter acting as an interface between the region with Gd suspension and the radiosensitive film substrate. The results for the 70 kVp beam quality showed dose increments of 6±6%, 22±7%, and 9±7% at different concentrations of 10, 20, and 30 mg/mL, respectively, verifying the competitive mechanisms of enhancement and attenuation. For the 50 kVp beam quality, no increase in dose was recorded for the concentrations studied, indicating that the major contribution to enhancement is from the K-edge interaction. In order to separate the contributions of attenuation and enhancement to the total dose, measurements were replicated with a 12 μm Mylar filter, obtaining a dose enhancement attributable to the K-edge of 29±7% and 34±7% at 20 and 30 mg/mL, respectively, evidencing a significant additional dose proportional to the Gd concentration.

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Serikbay, Arailym Talgatkyzy, Dmitry Vladimirovich Ageev, and Aidar Muratovich Aitkulov. "Anatomical parameters of Pisum sativum seedlings under the influence of macro- and nanoparticles of zinc." Bulletin of the Karaganda University. “Biology, medicine, geography Series” 110, no. 2 (June 30, 2023): 124–29. http://dx.doi.org/10.31489/2023bmg2/124-129.

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In Kazakhstan, the physicochemical properties of the nanoparticle were studied, but the physiological properties and toxicity to living organisms were not studied earlier. These studies have not been conducted in Kazakhstan, which presents broad prospects for scientific research. This paper presents the results of a comparative study of the anatomy of Pisum sativum seedlings exposed to macro- and nanoparticles of zinc of various concentrations (5, 10, 20 and 200 mg/100 ml). The anatomy of cross sections of vegetative organs of pea seedlings was studied. It has been established that zinc macro- and nanoparticles cause changes in the diameter of conductive beams, the thickness of internal and external tissues of the stem and root of seedlings. Differences in the influence of zinc nanoparticles on plant life processes depending on their concentration and the manifestation of their toxicity have been established. Thus, the determination of ways and means of the impact of metal nanoparticles on a living organism is an extremely important and relevant work necessary to establish scientifically-based concentrations and sizes of nanoparticles in water, air or in the composition of various materials with which a person comes into contact.

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Lazzarini, C. M., L. V. Goncalves, G. M. Grittani, S. Lorenz, M. Nevrkla, P. Valenta, T. Levato, S. V. Bulanov, and G. Korn. "Electron acceleration at ELI-Beamlines: Towards high-energy and high-repetition rate accelerators." International Journal of Modern Physics A 34, no. 34 (December 10, 2019): 1943010. http://dx.doi.org/10.1142/s0217751x19430103.

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The high energy electron experimental platform * at ELI-Beamlines will give to the users high energy tunable electron beams with low energy spread and divergence, by employing laser-wakefield-acceleration scheme (LWFA) driven by PW-class laser system working at 10 Hz. The platform will offer great flexibility over electron beam parameter space and is foreseen to exploit different targets, acceleration and laser-guiding advanced schemes. In this paper we summarize about more compact accelerators that can be envisioned by the use of really short (near single-cycle) fem-mJ-level laser pulses interacting with nanoparticle and solid targets, as well as with specific near-critical density targets. * Originally developed as H.E.L.L., within the Particle acceleration by Laser program (RP3).

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von Issendorff, B., and R. E. Palmer. "A new high transmission infinite range mass selector for cluster and nanoparticle beams." Review of Scientific Instruments 70, no. 12 (December 1999): 4497–501. http://dx.doi.org/10.1063/1.1150102.

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40

Rogers, D. W. O. "Comment on ‘Monte Carlo simulation on a gold nanoparticle irradiated by electron beams’." Physics in Medicine and Biology 58, no. 6 (March 4, 2013): 1999–2001. http://dx.doi.org/10.1088/0031-9155/58/6/1999.

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41

KITYK, I. V., N. ALZAYED, A. H. RESHAK, K. J. PLUCINSKI, J. BERDOWSKI, I. FUKS-JANCZAREK, R. MIEDZINSKI, and Z. TYLCZYNSKI. "OPTICALLY-OPERATED ELASTOOPTICAL EFFECTS IN POLYMER MATRICES WITH NANOCRYSTALLITES." Functional Materials Letters 04, no. 04 (December 2011): 357–59. http://dx.doi.org/10.1142/s179360471100224x.

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We have found that the optical treatment by bicolor two laser beams at 1064 and 532 nm, at energy densities 80–120 mJ/cm2 originating from the same 10 ns Nd3+ garnett lasers causes the occurrence of the piezooptical effect in 50–80 nm γ-glicyne polymer nanocomposites at nanoparticle content about 6.5% in weighting unit. We propose to use this effect for optical triggers.

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Etheridge, Joanne. "Local atomic structure determination using focused electron beams." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C26. http://dx.doi.org/10.1107/s2053273314099732.

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This talk will give an overview of methods for solving the atomic structure of nanostructured materials using focused electron beams. It will illustrate these methods with a range of applications, such as the determination of the atomic structure and stability of nanoparticle facets [1]; the local atomic structure of "chessboard' nanostructures in lithium-based titanate perovskites; and the measurement of local polarity, dopant concentration and atomic-scale morphology in semiconducting nanowire quantum wells. These methods take advantage of the fact that electron wavefields can be brought to a focal point smaller than an Ångström in diameter, enabling small volumes of matter to be probed and characterized. The wealth of information contained in the resulting diffraction patterns can be interrogated selectively to isolate and `image' specific structural information. Several methods using small focused electron beams will be described in this talk, including; (i) An approach for the determination of centrosymmetric structures from the direct observation of structure factor phases by inspection of features in convergent beam electron diffraction patterns [2]. The method can achieve high resolution from just a few phase observations and no intensity measurements or iterative refinements are required; (ii) Methods for the quantitative interpretation of the intensity in atomic resolution imaging and diffraction data for the measurement of local atomic and electronic structure; (iii) Pseudo-confocal scanning transmission electron microscopy methods for obtaining depth and chemical information which record the scattered intensity in a plane conjugate to the specimen (as opposed to the diffraction plane) [3].

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Vlastou, Elena, Evaggelos Pantelis, Efstathios P. Efstathopoulos, Pantelis Karaiskos, Vasileios Kouloulias, and Kalliopi Platoni. "Quantification of Nanoscale Dose Enhancement in Gold Nanoparticle-Aided External Photon Beam Radiotherapy." Cancers 14, no. 9 (April 26, 2022): 2167. http://dx.doi.org/10.3390/cancers14092167.

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The recent progress in Nanotechnology has introduced Gold Nanoparticles (AuNPs) as promising radiosensitizing agents in radiation oncology. This work aims to estimate dose enhancement due to the presence of AuNPs inside an irradiated water region through Monte Carlo calculations. The GATE platform was used to simulate 6 MV photon histories generated from a TrueBeam® linear accelerator with and without a Flattening Filter (FF) and model AuNPs clusters. The AuNPs size, concentration and distribution pattern were examined. To investigate different clinical irradiation conditions, the effect of field size, presence of FF and placement of AuNPs in water were evaluated. The range of Dose Enhancement Factors (DEF = DoseAu/DoseWater) calculated in this study is 0.99 ± 0.01–1.26 ± 0.02 depending on photon beam quality, distance from AuNPs surface, AuNPs size and concentration and pattern of distribution. The highest DEF is reported for irradiation using un-flattened photon beams and at close distances from AuNPs. The obtained findings suggest that dose deposition could be increased in regions that represent whole cells or subcellular targets (mitochondria, cell nucleus, etc.). Nevertheless, further and consistent research is needed in order to make a step toward AuNP-aided radiotherapy in clinical practice.

44

Vlastou, Elena, Evaggelos Pantelis, Efstathios P. Efstathopoulos, Pantelis Karaiskos, Vasileios Kouloulias, and Kalliopi Platoni. "Quantification of Nanoscale Dose Enhancement in Gold Nanoparticle-Aided External Photon Beam Radiotherapy." Cancers 14, no. 9 (April 26, 2022): 2167. http://dx.doi.org/10.3390/cancers14092167.

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The recent progress in Nanotechnology has introduced Gold Nanoparticles (AuNPs) as promising radiosensitizing agents in radiation oncology. This work aims to estimate dose enhancement due to the presence of AuNPs inside an irradiated water region through Monte Carlo calculations. The GATE platform was used to simulate 6 MV photon histories generated from a TrueBeam® linear accelerator with and without a Flattening Filter (FF) and model AuNPs clusters. The AuNPs size, concentration and distribution pattern were examined. To investigate different clinical irradiation conditions, the effect of field size, presence of FF and placement of AuNPs in water were evaluated. The range of Dose Enhancement Factors (DEF = DoseAu/DoseWater) calculated in this study is 0.99 ± 0.01–1.26 ± 0.02 depending on photon beam quality, distance from AuNPs surface, AuNPs size and concentration and pattern of distribution. The highest DEF is reported for irradiation using un-flattened photon beams and at close distances from AuNPs. The obtained findings suggest that dose deposition could be increased in regions that represent whole cells or subcellular targets (mitochondria, cell nucleus, etc.). Nevertheless, further and consistent research is needed in order to make a step toward AuNP-aided radiotherapy in clinical practice.

45

Deng, Tian-Song, John Parker, Yuval Yifat, Nolan Shepherd, and Norbert F. Scherer. "Dark Plasmon Modes in Symmetric Gold Nanoparticle Dimers Illuminated by Focused Cylindrical Vector Beams." Journal of Physical Chemistry C 122, no. 48 (November 26, 2018): 27662–72. http://dx.doi.org/10.1021/acs.jpcc.8b10415.

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46

Birman, V., K. Chandrashekhara, M. S. Hopkins, and J. S. Volz. "Effects of nanoparticle impregnation of polyurethane foam core on the performance of sandwich beams." Composites Part B: Engineering 46 (March 2013): 234–46. http://dx.doi.org/10.1016/j.compositesb.2012.09.026.

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47

Kasakewitsch, Alla, Uwe Arlic, and Werner Riehemann. "Mechanical Properties of Aluminum-Matrix-Nanoparticle-Composites." Key Engineering Materials 742 (July 2017): 145–50. http://dx.doi.org/10.4028/www.scientific.net/kem.742.145.

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Aluminium-Matrix-Nanoparticle-Composites were produced by ball milling of micro scale Aluminium powder with various nanoscales ceramic powders like Silicon Carbide, Alumina and Boron Nitride with subsequent consolidation by hot extruding. The composites were investigated by amplitude dependent damping tests, tensile tests at elevated temperatures, hardness measurements, imaging methods and electric conductivity tests. All tested samples were machined out of hot extruded rods. The Amplitude dependent damping of bending samples was determined by measuring the strain dependent logarithmic decrement of free decaying vibrations of bending beams at room temperature. These tests were done after successive step by step isochronal heat treatments. Some samples show substantial improvement of the mechanical properties due to dispersion hardening or grain refinement. It can be concluded that the results are mainly influenced by dislocation effects like Orowan-effect, work-hardening, grain-size-hardening, recrystallization, and creation of dislocations at ceramic particles due to thermal mismatch. Moreover some results can be attributed to fatigue during mechanical cycling namely crack nucleation, crack growth and fraction. The electric conductivity was measured indirectly by permeability tests with a digital hysteresis recording devise. The results show the low influence of nano-particle dispersion hardening to conductivity in comparison of work-hardening.

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Borodaenko, Yulia, Evgeniia Khairullina, Aleksandra Levshakova, Alexander Shmalko, Ilya Tumkin, Stanislav Gurbatov, Aleksandr Mironenko, et al. "Noble-Metal Nanoparticle-Embedded Silicon Nanogratings via Single-Step Laser-Induced Periodic Surface Structuring." Nanomaterials 13, no. 8 (April 7, 2023): 1300. http://dx.doi.org/10.3390/nano13081300.

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Here, we show that direct femtosecond laser nanostructuring of monocrystalline Si wafers in aqueous solutions containing noble-metal precursors (such as palladium dichloride, potassium hexachloroplatinate, and silver nitrate) allows for the creation of nanogratings decorated with mono- (Pd, Pt, and Ag) and bimetallic (Pd-Pt) nanoparticles (NPs). Multi-pulse femtosecond-laser exposure was found to drive periodically modulated ablation of the Si surface, while simultaneous thermal-induced reduction of the metal-containing acids and salts causes local surface morphology decoration with functional noble metal NPs. The orientation of the formed Si nanogratings with their nano-trenches decorated with noble-metal NPs can be controlled by the polarization direction of the incident laser beam, which was justified, for both linearly polarized Gaussian and radially (azimuthally) polarized vector beams. The produced hybrid NP-decorated Si nanogratings with a radially varying nano-trench orientation demonstrated anisotropic antireflection performance, as well as photocatalytic activity, probed by SERS tracing of the paraaminothiophenol-to-dimercaptoazobenzene transformation. The developed single-step maskless procedure of liquid-phase Si surface nanostructuring that proceeds simultaneously with the localized reduction of noble-metal precursors allows for the formation of hybrid Si nanogratings with controllable amounts of mono- and bimetallic NPs, paving the way toward applications in heterogeneous catalysis, optical detection, light harvesting, and sensing.

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Liu, Di, Le Yu, Xiao Xiong, Lei Yang, Yan Li, Ming Li, Hai-Ou Li, et al. "Improving the luminescence enhancement of hybrid Au nanoparticle-monolayer MoS_2 by focusing radially-polarized beams." Optics Express 24, no. 24 (November 17, 2016): 27554. http://dx.doi.org/10.1364/oe.24.027554.

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Yang, Y., I. Gadjev, J. Rosenzweig, and K. Sheng. "Gold Nanoparticle Dose Enhancement of Inverse-Compton Based Monoenergetic Photon Beams: A Monte Carlo Evaluation." International Journal of Radiation Oncology*Biology*Physics 99, no. 2 (October 2017): E744. http://dx.doi.org/10.1016/j.ijrobp.2017.06.2390.

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