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To examine detail depth dose characteristics of ideal proton beams using the GATE Monte Carlo technique.
In this study, in order to improve simulation efficiency, we used pencil beam geometry instead of parallel broad-field geometry. Depth dose distributions for beam energies from 5 to 250 MeV in a water phantom were obtained. This study used parameters named Rpeak, R90, R80, R73, R50, full width at half maximum (FWHM), width of 80–20% distal fall-off (W(80–20)) and peak-to-entrance ratio to represent Bragg peak characteristics. The obtained energy–range relationships were fitted into third-order polynomial formulae. The present study also used the GATE Monte Carlo code to calculate the stopping power of proton pencil beams in a water cubic phantom and compared results with the National Institute of Standards and Technology (NIST) standard reference database.
The study results revealed deeper penetration, broader FWHM and distal fall-off and decreased peak-to-entrance dose ratio with increasing beam energy. Study results for monoenergetic proton beams showed that R73 can be a good indicator to characterise a range of incident beams. These also suggest FWHM is more sensitive than W(80–20) distal fall-off in finding initial energy spread. Furthermore, the difference between the obtained stopping power from simulation and NIST data almost in all energies was lower than 1%.
Detail depth dose characteristics for monoenergetic proton beams within therapeutic energy ranges were reported. These results can serve as a good reference for clinical practitioners in their daily practice.
Efficient electron acceleration by a linearly chirped ultrashort laser pulse in vacuum is investigated using the particle swarm optimization method. By applying this method for optimizing the initial parameters of the laser pulse, a pronounced increase in final energy gain of the electron is obtained compared to that expected from the successive optimization method. Our results also suggest that the value of the optimal chirp parameter is independent of laser polarization and the energy gain could be insensitive to the sign of this parameter when the initial phase is optimally adjusted. In addition, utilizing the chirped laser pulse with optimized conditions for acceleration of an electron bunch reveals that the energy spectrum is shifted to considerably higher energies and the spatial distribution is significantly improved in a polarization-dependent manner.
Mass gatherings (MGs) are held throughout the world. The aim of this review was to assess and identify the health threats based on the type of the MG, type of diseases, and injuries. Research platforms such as Web of Science, Medline, and Scopus were searched through June 2017. All epidemiologic studies that investigated the health threats during the MGs, such as communicable diseases, injuries, high-risk behaviors, and environmental health problems, were included in this review. Out of 1264 references, 45 articles were included in the review.
Three main types of MGs include religious, festival, and sporting event; and fairs such as trade, book, and agricultural types were also reported in the selected studies. In the religious MGs, infectious diseases were the most common health threat. Road traffic accidents and environmental health problems were additional health threats. At MG sporting events, injuries were the most common health problems. Infectious diseases and alcohol and drug-related disorders were other reported public health concerns. In the festival MGs, alcohol and drug-related problems were commonly reported. This review showed that health threats vary, based on the type of mass gathering. The health organizers of MGs should consider the type of the MG and the health needs and safety of the participants to help them plan their action and provide the needed health care services.
We study linear mappings which preserve vectors at a specific angle. We introduce the concept of
-angle preserving mappings and define
as the ‘smallest’ number
-angle preserving mapping. We derive an exact formula for
in terms of the norm
and the minimum modulus
. Finally, we characterise approximately angle preserving mappings.
This study evaluated the effects of Mg administration on carotid intima–media thickness (CIMT), glycaemic control and markers of cardio-metabolic risk in diabetic haemodialysis (HD) patients. This randomised, double-blind, placebo-controlled clinical trial was conducted in fifty-four diabetic HD patients. Participants were randomly divided into two groups to take either 250 mg/d Mg as magnesium oxide (n 27) or placebo (n 27) for 24 weeks. Mg supplementation resulted in a significant reduction in mean (P<0·001) and maximum levels of left CIMT (P=0·02) and mean levels of right CIMT (P=0·004) compared with the placebo. In addition, taking Mg supplements significantly reduced serum insulin levels (β=–9·42 pmol/l; 95% CI –14·94, –3·90; P=0·001), homoeostasis model of assessment-insulin resistance (β=–0·56; 95 % CI –0·89, –0·24; P=0·001) and HbA1c (β=–0·74 %; 95 % CI –1·10, –0·39; P<0·001) and significantly increased the quantitative insulin sensitivity check index (β=0·008; 95 % CI 0·002, 0·01; P=0·002) compared with the placebo. In addition, Mg administration led to a significant reduction in serum total cholesterol (β=–0·30 mmol/l; 95% CI –0·56, –0·04; P=0·02), LDL-cholesterol (β=–0·29 mmol/l; 95% CI –0·52, –0·05; P=0·01), high-sensitivity C-reactive protein (hs-CRP) (P<0·001) and plasma malondialdehyde (MDA) (P=0·04) and a significant rise in plasma total antioxidant capacity (TAC) levels (P<0·001) compared with the placebo. Overall, we found that taking Mg for 24 weeks by diabetic HD patients significantly improved mean and maximum levels of left and mean levels of right CIMT, insulin metabolism, HbA1c, total cholesterol and LDL-cholesterol, hs-CRP, TAC and MDA levels.
The present review aimed to quantify the association of dietary intake and circulating concentration of major dietary antioxidants with risk of total CVD mortality.
Systematic review and meta-analysis.
Systematic search in PubMed and Scopus, up to October 2017.
Prospective observational studies reporting risk estimates of CVD mortality across three or more categories of dietary intakes and/or circulating concentrations of vitamin C, vitamin E and β-carotene were included. A random-effects meta-analysis was conducted.
A total of fifteen prospective cohort studies and three prospective evaluations within interventional studies (320 548 participants and 16 974 cases) were analysed. The relative risks of CVD mortality for the highest v. the lowest category of antioxidant intakes were as follows: vitamin C, 0·79 (95 % CI 0·68, 0·89; I2=46 %, n 10); vitamin E, 0·91 (95 % CI 0·79, 1·03; I2=51 %, n 8); β-carotene, 0·89 (95 % CI 0·73, 1·05; I2=34 %, n 4). The relative risks for circulating concentrations were: vitamin C, 0·60 (95 % CI 0·42, 0·78; I2=65 %, n 6); α-tocopherol, 0·82 (95 % CI 0·76, 0·88; I2=0 %, n 5); β-carotene, 0·68 (95 % CI 0·52, 0·83; I2=50 %, n 6). Dose–response meta-analyses demonstrated that the circulating biomarkers of antioxidants were more strongly associated with risk of CVD mortality than dietary intakes.
The present meta-analysis demonstrates that higher vitamin C intake and higher circulating concentrations of vitamin C, vitamin E and β-carotene are associated with a lower risk of CVD mortality.
We seek a sufficient condition which preserves almost-invariant subspaces under the weak limit of bounded operators. We study the bounded linear operators which have a collection of almost-invariant subspaces and prove that a bounded linear operator on a Banach space, admitting each closed subspace as an almost-invariant subspace, can be decomposed into the sum of a multiple of the identity and a finite-rank operator.
This study aimed to assess the cost-effectiveness of ivabradine plus standard of care (SoC) in comparison with current SoC alone from the Iranian payer perspective.
A cohort-based Markov model was developed to assess the incremental cost-effectiveness ratio (ICER) over a 10-year time horizon in a cohort of 1,000 patients. The baseline transition probabilities between New York Heart Association (NYHA), mortality rate, and hospitalization rate were extracted from the literature. The effect of ivabradine on mortality, hospitalization, and NYHA improvement or worsening were retrieved from the SHIFT study. The effectiveness was measured as quality-adjusted life-years (QALYs) using the utility values derived from Iranian Heart Failure Quality of Life study. Direct medical costs were obtained from hospital records and national tariffs. Deterministic and probabilistic sensitivity analyses were conducted to show the robustness of the model.
Ivabradine therapy was associated with an incremental cost per QALY of USD $5,437 (incremental cost of USD $2,207 and QALYs gained 0.41) versus SoC. The probabilistic sensitivity analysis showed that ivabradine is expected to have a 60 percent chance of being cost-effective accepting a threshold of USD $6,550 per QALY. Furthermore, deterministic sensitivity analysis indicated that the model is sensitive to the ivabradine drug acquisition cost.
The cost-effectiveness model suggested that the addition of ivabradine to SoC therapy was associated with improved clinical outcomes along with increased costs. The analysis indicates that the clinical benefit of ivabradine can be achieved at a reasonable cost in eligible heart failure patients with sinus rhythm and a baseline heart rate ≥ 75 beats per minute (bpm).
To validate the Geant4 Application for Tomographic Emission (GATE) Monte Carlo simulation code by calculating the proton beam range in the therapeutic energy range.
Materials and methods
In this study, the GATE code which is based on Geant4 was used for simulation. The proton beams in the therapeutic energy range (5–250 MeV) were simulated in a water medium, and then compared with the data from National Institute of Standards and Technology (NIST) in order to investigate the accuracy of different physics list available in the GATE code. In addition, the optimal value of SetCut was assessed.
In all energy ranges, the QBBC physics had a greater deviation in the ranges relative to the NIST data. With respect to the range calculation accuracy, the QGSP_BIC_EMY and QGSP_BERT_HP_EMY physics were in the range of statistical uncertainty; however, QGSP_BIC_EMY produced better results using the least squares. Based on an investigation into the range calculation precision and simulation efficiency, the optimal SetCut was set at 0·1 mm.
Based on an investigation into the range calculation precision and simulation yield, the QGSP_BIC_EMY physics and the optimal SetCut was recommended to be 0·1 mm.
Currently, rescue in vitro maturation (IVM) is not a routine method in assisted reproductive treatment (ART) programmes but is a promising procedure for ART to improve IVM. The aim of this study was to compare embryo morphokinetics of germinal vesicles (GV) with metaphase II (MII) oocytes from controlled ovarian hyperstimulation (COH) cycles by time-lapse photography monitoring (TLM). Morphokinetics of the same number of embryos derived from the in vivo (group I) and rescue of in vitro matured oocytes (group II) from 310 patients were analyzed and compared retrospectively. The time to form second PB extrusion (tPB2), time of pronuclei appearance (tPNa), time of pronuclei fading (tPNf) and time of two to eight discrete cells (t2–t8) were assessed. Abnormal cleavage patterns such as uneven blastomeres at the two-cell stage, cell fusion (Fu), trichotomous mitoses (TM), and the rates of embryo arrest were assessed. These data showed that tPB2, tPNa, tPNf, t2, t3 and t4 stages took place later in group II compared with group I (P<0.001, P=0.017, P<0.001, P<0.001, P<0.001, P<0.001, respectively). The rates of uneven blastomeres, Fu, TM, and embryo arrest were increased significantly in group II compared with group I (P=0.001, P<0.001, P=0.003, P<0.001, respectively). Based on the exact annotation of timing parameters and cleavage patterns, the present data agreed with the concept that rescue IVM of oocytes negatively influences embryo morphokinetics. Therefore, cautious use of embryos derived from rescue IVM of GV oocytes should be made.
This study deals with the problem of trajectory tracking of wheeled mobile robots (WMR's) under non-holonomic constraints and in the presence of model uncertainties. To solve this problem, the kinematic and dynamic models of a WMR are first derived by applying the recursive Gibbs–Appell method. Then, new kinematics- and dynamics-based multivariable controllers are analytically developed by using the predictive control approach. The control laws are optimally derived by minimizing a pointwise quadratic cost function for the predicted tracking errors of the WMR. The main feature of the obtained closed-form control laws is that online optimization is not needed for their implementation. The prediction time, as a free parameter in the control laws, makes it possible to achieve a compromise between tracking accuracy and implementable control inputs. Finally, the performance of the proposed controller is compared with that of a sliding mode controller, reported in the literature, through simulations of some trajectory tracking maneuvers.
A comprehensive meta-analysis study was performed to estimate the reliable national prevalence and molecular epidemiology of amoebiasis in Iran. Nine English and Persian databases were searched to achieve the relevant studies. Pooled estimates were generated and meta-regression was performed. We identified 71 eligible articles involving 330 930 subjects from 25 provinces to be included in the final analysis. Moreover, 17 studies compromising 462 polymerase chain reaction (PCR)-positive isolates performed molecular analysis to inter-species differentiation. The pooled prevalence of Entamoeba infection among Iranian population was about 1% (95% CI 0.8–2.0%). Moreover, regarding Human Development Index (HDI), a higher prevalence was observed in undeveloped provinces. Out of 462 PCR-positive isolates, 83% (95% CI 69–94%) and 12% (95% CI 3–24%) were Entamoeba dispar, Entamoeba histolytica, respectively. In subgroup analysis based on molecular results, in general, population prevalence of Entamoeba dispar and E. histolytica were 91% (95% CI 80–99%) and 7%, (95% CI 0–19%), respectively, while prevalence of these species in patients with gastrointestinal disorders were 75% (95% CI 45–96%) and 18% (95% CI 1–43%), respectively. Our findings indicate the low burden of amoebiasis in Iran. E. dispar, that is mostly non-pathogenic, was identified as most prevalent species. Nevertheless, we suggest more public health interventions in areas with lower HDI.
Cumulus cells (CCs) play an important role in the regulation of female gamete development, meiotic maturation, oocyte–sperm interaction, capacitation and acrosome reaction. However, their role in maintaining oocyte competence after vitrification is unclear as controversial data on their protecting action against oocyte cryoinjuries are available. Here we described the effects of vitrification on the ultrastructure of human CCs collected from women undergoing assisted reproductive technologies (ARTs). In total, 50 patches of CCs, sampled from high-quality human cumulus–oocyte complexes, were randomly allocated into two groups after patient informed consent: 1, fresh CCs (controls, n = 25); 2, vitrified CCs (n = 25). Samples were then prepared and observed by transmission electron microscopy. In fresh CCs, in which small cell clusters were visible, cell membranes were joined by focal gap junctions. Microvilli were rare and short. Nuclei, mitochondria, smooth endoplasmic reticulum (SER), Golgi apparatus and lipid droplets appeared well preserved; vacuoles were scarce. After vitrification, we observed two populations of CCs: light CCs, with a smooth appearance and few short microvilli; and dark CCs, with numerous and long microvilli. In both, most of the organelles appeared similar to those of fresh CCs. Lipid droplets were denser and more numerous, with respect to fresh CCs. They were mainly located in the peri-nuclear and sub-plasmalemmal regions. Numerous packed electron-negative vacuoles were visible. The vitrification procedure did not cause alterations in the fine structure of major organelles, except for an increased amount of lipid droplets and vacuoles. This specific sensitivity of human CCs to vitrification should be considered during ARTs.
The present work demonstrates controllable directive radiation of a dipolar emitter coupled to a substrate-supported dielectric nanowire antenna. Nanoactuators, transparent-conducting oxides, and graphene are integrated into the substrate, respectively, to establish tunable antenna platforms in visible, near-infrared (IR), and far-IR frequency regimes. We exploit the substrate-induced interference effects and tunability mechanisms in each antenna system to achieve directive radiation with real-time steering capability. The design and modeling are rigorously carried out using an efficient and accurate semi-analytical framework based on transition matrix formulation. Each configuration is optimized to achieve maximal steering range while attaining a proper gain. Owing to subwavelength footprint, enhanced directionality, real-time tunability, and fairly simple geometry, the proposed platforms are ideal candidates for nanoantenna synthesis.
One of the most important measures following disasters is setting up a communicable disease surveillance system (CDSS). This study aimed to develop indicators to assess the performance of CDSSs in disasters.
In this 3-phase study, firstly a qualitative study was conducted through in-depth, semistructured interviews with experts on health in disasters and emergencies, health services managers, and communicable diseases center specialists. The interviews were analyzed, and CDSS performance assessment (PA) indicators were extracted. The appropriateness of these indicators was examined through a questionnaire administered to experts and heads of communicable diseases departments of medical sciences universities. Finally, the designed indicators were weighted using the analytic hierarchy process approach and Expert Choice software.
In this study, 51 indicators were designed, of which 10 were related to the input (19.61%), 17 to the process (33.33%), 13 to the product (25.49%), and 11 to the outcome (21.57%). In weighting, the maximum score was that of input (49.1), and the scores of the process, product, and outcome were 31.4, 12.7, and 6.8, respectively.
Through 3 different phases, PA indicators for 4 phases of a chain of results were developed. The authors believe that these PA indicators can assess the system’s performance and its achievements in response to disasters. (Disaster Med Public Health Preparedness. 2019;13:158–164)
Millimeter-wave (mm-wave) beam-steering antennas are preferred for reducing the disruptive effects, such as those caused by high atmospheric debilitation in wireless communications systems. In this work, a compact broadband antenna array with a low loss feed network design is introduced. To overcome the short-range effects on mm-wave frequencies, a feed network – with a modified Butler matrix and a compact zeroth-order resonance antenna element – has been designed. Furthermore, the aperture feed technique has been utilized to provide a broadside stable pattern and improve the delivered gain. A Fabry-Perot layer without the height of the air layer is used. Taking advantage of this novel design, a broadband and compact beam-steering array antenna – capable of covering impedance bandwidths (from 33.84 to 36.59 GHz) and scanning a solid angle of about ~94°, with a peak gain of 17.6 dBi – is attained.
A novel concept of using fractal antenna with metamaterial and slot to achieve multiband operation is investigated. The antenna consists of an L-shaped slot, Sierpinski triangle (used as fractal) as the radiating part and metamaterial circular split ring resonator (SRR) as the ground plane. The introduction of metamaterial in the ground plane makes the antenna operate at 3.3 GHz (middle WiMAX). The etching of Sierpinski triangle and L-shaped slot in the radiating monopole perturbs the surface current distribution; thereby increasing the total current path length which tends the antenna to further operate at 5.5 (upper WiMAX), 7.3 (satellite TV) and 9.9 GHz (X-band), respectively. The extraction of medium parameter of a circular SRR through waveguide medium is discussed in detail. The antenna has a compact dimension of 0.33λ0 × 0.27λ0 × 0.01λ0 = 30 mm × 24.8 mm × 1.6 mm, at a lower frequency of 3.3 GHz. Under simulation, antenna operates at 3.3, 5.5, 7.3 and 9.9 GHz with S11 < −10 dB bandwidth of about 5.9% (3.24–3.44 GHz), 5.6% (5.31–5.62 GHz), 7.3% (6.99–7.52 GHz) and 3.02% (9.78–10.08 GHz), respectively. In measurement, antenna exhibit resonances at 3.1, 5.52, 7.31, 9.72 GHz with S11 < −10 dB bandwidth of about 3.5% (3.04–3.15 GHz), 5.01% (5.44–5.72 GHz), 13.2% (6.76–7.72 GHz) and 5.77% (9.42–9.98 GHz), respectively. Good impedance matching and stable radiation characteristics are observed across the operational bandwidth of the proposed configuration.