Stonekristiansen6051

Several direct algorithms have been proposed to take into account the non-linear path of protons in the reconstruction of a proton CT (pCT) image. ND630 This paper presents a comparison between five of them, in terms of spatial resolution and relative stopping power (RSP) accuracy. Our comparison includes (1) a distance-driven algorithm extending the filtered backprojection to non-linear trajectories (DD), (2) an algorithm reconstructing a pCT image from optimized projections (ML), (3) a backproject-then-filter approach using a 2D cone filter (BTF), (4) a differentiated backprojection algorithm based on the inversion of the Hilbert transform (DBP), and (5) an algorithm using a 2D directional ramp filter (DR). We have simulated a single tracking pCT set-up using Geant4 through GATE, with a proton source and two position, direction and energy detectors upstream and downstream from the object. Tracker uncertainties were added on the position and direction measurements. A Catphan 528 phantom and a spiral phantom were sn from truncated data - can be used for a reduced reconstruction time. © 2020 Institute of Physics and Engineering in Medicine.We prepared the ZnO nanocomposites with WO3or CuO nanostructures to improve the photocatalytic performance of ZnO nanostructures. The characterizations of the nanocomposites by using SEM, X-ray diffractor, UV-vis spectrometer, and photoluminescence reveal the morphologies and wide light absorption range of materials. The highest current densities of WO3/ZnO and CuO/ZnO nanocomposites were up to 1.28 mA/cm2and 2.49 mA/cm2at 1.23V (vs RHE) under AM 1.5 100 mW/cm2, which are ~ 1.2 and 3.5-fold greater than that of the ZnO nanostructures, respectively. The facile fabrication process suggests that nanocomposite with narrow bandgap materials, such as WO3and CuO, would improve the performance of electrochemical and optoelectrical devices, such as dye-sensitized solar cells and biosensor. © 2020 IOP Publishing Ltd.Previous work has shown that PRESAGE® can be used successfully to perform 3D dosimetric measurements of complex radiotherapy treatments. However, measurements near the sample edges are known to be difficult to achieve. This is an issue when the doses at air-material interfaces are of interest, for example when investigating the electron return effect (ERE) present in treatments delivered by magnetic resonance (MR)-linac systems. To study this effect, a set of 3.5 cm-diameter cylindrical PRESAGE® samples was uniformly irradiated with multiple dose fractions, using either a conventional linac or an MR-linac. The samples were imaged between fractions using an optical-CT, to read out the corresponding accumulated doses. A calibration between TPS-predicted dose and optical-CT pixel value was determined for individual dosimeters as a function of radial distance from the axis of rotation. This data was used to develop a correction that was applied to four additional samples of PRESAGE® of the same formulation, irradiated with 3D-CRT and IMRT treatment plans, to recover significantly improved 3-D measurements of dose. An alternative strategy was also tested, in which the outer surface of the sample was physically removed prior to irradiation. Results show that for the formulation studied here, PRESAGE® samples have a central region that responds uniformly and an edge region of 6-7 mm where there is a gradual increase in dosimeter response, rising to an over-response of 24-36% at the outer boundary. This non-uniform dose-response increases in both extent and magnitude over time. Both mitigation strategies investigated were successful. In our four exemplar studies, we show how discrepancies at edges are reduced from 13-37% of the maximum dose to between 2 and 8%. Quantitative analysis shows that the 3-D gamma passing rates rise from 90.4, 69.3, 63.7 and 43.6% to 97.3, 99.9, 96.7 and 98.9% respectively. Creative Commons Attribution license.OBJECTIVE Nowadays, photoplethysmogram (PPG) signals have been widely used to estimate blood pressure (BP) cufflessly and continuously, in which a number of different PPG features have been proposed and extracted from PPG signals for an objective of accurate BP estimation. However, the underlying physiological mechanism for PPG-based BP estimation still remains unclear, particularly those corresponding various PPG features. In this study, the physiological mechanism of existing PPG features for BP estimation was investigated, which may provide an insight into the physiological mechanism. APPROACH Experiments with cold stimuli and exercise trial were designed to change the total peripheral vascular resistance (TPR) and cardiac output (CO), respectively. Instantaneous BP and continuous PPG signal from 12 healthy subjects were recorded throughout the experiments. link2 A total of 65 PPG features were extracted from the original, the first derivative, and the second derivative waves of PPG. The significance of the change of PPG features in the cold stimuli phase and in the early exercise recovery period was compared with that in the baseline phase. RESULTS Intensity-specific PPG features changed significantly (p less then 0.05) in the cold stimuli phase than in the baseline phase, demonstrating they were TPR-correlated. Time-specific PPG features changed significantly (p less then 0.05) in the early exercise recovery period than in the baseline phase, suggesting they were CO-correlated. And most of the PPG features associated with slope and area changed obviously both in the cold stimuli phase and in the early exercise recovery period, indicating that they should be TPR-correlated and CO-correlated. SIGNIFICANCE The findings of this study explained the intrinsic physiological mechanism why the proposed PPG features could be applied to BP estimation, and provided insights for exploring more diagnostic applications of the PPG features. © 2020 Institute of Physics and Engineering in Medicine.Drug delivery carriers hold tremendous promise for improving cancer treatment. The polyrotaxane has shown excellent value as a drug carrier. However, few references reported that water solution polyrotaxane with fluorescence as drug carrier is free of labeling with organic fluorescence dyes. Herein, we synthesized a drug-loaded fluorescent polyrotaxane with porphyrin terminating, which can be used as a tracer material in drug and gene delivery. The structure, morphology and zeta potential of the porphyrin-terminated polyrotaxane (PR-COOH) were characterized by nuclear magnetic resonance (NMR), high resolution transmission electron microscope (HR-TEM) and zeta potentiometer. In this research, the cisplatin (CDDP) is used as a model drug. The zeta potential, drug encapsulation efficiency and drug release of CDDP-loaded polyrotaxane (PR-COOH-Pt) were studied. Confocal laser scanning microscopy (CLSM) showed that PR-COOH could be internalized by HeLa cells and CT26 cells. The antitumor efficacy of PR-COOH-Pt was investigated in vitro by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and in vivo by a xenograft tumor model. The results showed that the PR-COOH-Pt could significantly inhibit tumor growth, thus the PR-COOH-Pt hold a promising role in cancer therapy. © 2020 IOP Publishing Ltd.We investigate the optical properties of strain-free mesoscopic GaAs/Al(x)Ga(1-x)As structures (MGS) coupled to thin GaAs/A(x)Ga(1-x)As quantum wells (QWs) with varying Al content (x). We demonstrate that quenching the QW emission by controlling the band crossover between AlGaAs X-point and GaAs Gamma-point gives rise to long carrier lifetimes and enhanced optical emission from the MGS. For x = 0.33, QW and MGS show typical type-I band alignment with strong QW photoluminescence emission and much weaker sharp recombination lines from the MGS localized exciton states. link3 For x >= 0.50, the QW emission is considerably quenched due to the change from type-I to type-II structure while the MGS emission is enhanced due to carrier injection from the QW. For x >= 0.70, we observe PL quenching from the MGS higher energy states also due to the crossover of X and Gamma bands, demonstrating spectral filtering of the MGS emission. Time-resolved measurements reveal two recombination processes in the MGS emission dynamics. The fast component depends mainly on the X-Gamma mixing of the MGS states and can be increased from 0.3 to 2.5~ns by changing the Al content. The slower component, however, depends on the X-Gamma mixing of the QW states and is associated to the carrier injection rate from the QW reservoir into the MGS structure. In this way, the independent tuning of X-Gamma mixing in QW and MGS states allows us to manipulate recombination rates in the MGS as well as to make carrier injection and light extraction more efficient. © 2020 IOP Publishing Ltd.Clean and eco-friendly synthesis of silver nanoparticles (AgNPs) proved to have promising characteristics with impressive biomedical related potentials. Here, we have employed the green process for the synthesis of AgNPs using kenaf seed (KS) extract as a bilateral mediator of reducing and capping of Ag+ ions under hydrothermal condition. The synthesis pathways, such as varying amounts of KS, silver ions concentration, and autoclaving time were optimized. A manifestation of a strong absorption peak from 420 to 430 nm in UV-Vis spectroscopy indicated fruitful synthesis of KS@AgNPs. Fourier transform infrared spectroscopy confirmed the presence of hydroxyl and carbonyl functionalities to be involved in the reduction and stabilization of Ag+ ions. Besides, Transmission electron microscopy revealed that the KS@AgNPs possess spherical in shape having a size around 7-11 nm, whereas high-quality crystals were evidenced by X-ray diffraction analysis. Moreover, inductively coupled plasma-optical emission spectrometry revealed that 19.6 μg/L of Ag+ ions was released from KS@AgNPs. In cell line studies, KS@AgNPs at a higher dose was unveiled as non-toxic to the healthy (NIH3T3) cells, while strong anti-proliferative response was found in the case of lung cancer (A549) cells. Furthermore, a significant zone of inhibition was observed for both Gram-positive and Gram-negative microorganisms, and a combination of KS@AgNPs with ampicillin exposed notable synergistic anti-pathogenic effect. Overall, our study proved the potentiality of KS as an efficient bio-resource for the synthesis of AgNPs and also their original feature as an anti-cancer and antimicrobial agent. © 2020 IOP Publishing Ltd.A system containing polyoxometalate ([Co-POM]2-) and [Ru(bpy)3]2+ were constructed for visible-light-induced CO2 conversion to syngas. In diluted CO2, high efficiency of 56.8 mmol g-1 h-1 in syngas production was gained, exceeding that of reported systems with [Ru(bpy)3]2+ participation in similar condition. Mechanism studies revealed efficient photo-induced charge separation is achieved in the system and CO2 reduction tends to occur on [Ru(bpy)3]2+. © 2020 IOP Publishing Ltd.This study examined the identity profiles that upper secondary school Finnish student-athletes show and the extent to which these profiles were associated with their athletic and academic achievements and withdrawal from sports and school. A total of 391 adolescent athletes (51% female) completed assessments of student and athletic identity four times during their time in upper secondary school. Using growth mixture modeling, three groups were identified dual identity (77%), changing identity (5%), and athletic identity (18%). The higher the academic achievement was at Time 1, the more likely the athletes were to show a dual identity than an athletic identity profile. Similarly, athletes with dual identity showed higher subsequent academic achievement at Time 4 than those with an athletic identity profile. Finally, athletes with dual identity were more likely and athletes with athletic identity less likely to withdraw from sport activities during upper secondary school than would be expected by chance.