Dw Values Research Articles

Relationship between Low-Contrast Detectability and Water-Equivalent Diameter on the Hitachi Water Phantom

This study aims to determine relationship between water-equivalent diameter (Dw) and low-contract detectability (LCD) for various reconstruction filters. The water phantoms were Hitachi phantoms with diameters of 16, 22.5, 30, and 38 cm. The phantoms were scanned with a 64-slice Hitachi CT Scanner and reconstructed with various reconstruction filters (i.e., bone, head and abdomen filters). The Dw values were automatically calculated using IndoseCT software. The noise and minimum detectable contrast (MDC) of LCD were automatically calculated using IndoQCT software. It is found that Dw corresponds to the phantom diameter and is not affected by any of the reconstruction filters. Noise is affected by phantom diameter and reconstruction filter. Minimum detectable contrast is strongly affected by the phantom diameter and reconstruction filter. The minimum detectable contrast increases with the increase of the phantom diameter. Therefore, optimization needs to be done for different patient sizes and different filter reconstruction for clinical applications.

Adsorption of terbium (III) on DGA and LN resins: Thermodynamics, isotherms, and kinetics

Two commercially available extraction chromatography (EXC) resins containing N,N,N’,N’-tetra-n-octyldiglycolamide (DGA Resin, Normal, 50 – 100 μm) and Bis(2-ethylhexyl) phosphate (LN Resin, 100 – 150 μm) were used as adsorbents to study fundamental adsorption properties such as thermodynamic values, equilibrium isotherms, and kinetic uptake models for terbium(III) adsorption. Weight distribution ratios (Dw) for terbium on DGA and LN resins were measured using a [160Tb]Tb3+radiometric tracer in nitric acid as a function of acidity, temperature, initial analyte concentration, and equilibrium time. The Dw values showed increasing binding affinity for DGA resin at high nitric acid concentrations and decreasing binding affinity for LN resins. Thermodynamic studies for DGA and LN resins revealed that the Gibbs free energy (ΔG) increased consistently with temperature. To model equilibrium data, increasingly higher parameter equilibrium isotherm models (Henry (1) < Langmuir, Freundlich (2) < Redlich-Peterson (3) < Fritz-Schluender (4)) were compared on their root mean squared errors (RMSE) and adjusted determination coefficients to determine the most applicable model. In all cases, the empirical four-parameter Fritz-Schluender isotherm demonstrated a superior fit. Similar comparisons for reaction-based kinetic models (Pseudo-first-order < Pseudo-second-order < Pseudo-n-order) revealed that the higher-order PNO model yielded a superior fit of kinetic data for both resins. However, in some cases, adsorption isotherms and kinetic models could also be modeled by a lower-order model with minimal change in error parameters. Weber-Morris plots revealed that two linear sections are observed for each resin, where the first linear segment is attributed to fast (film diffusion) adsorption of terbium, followed by slower intraparticle diffusion of terbium through the pores as the rate-limiting step. Based on the Weber-Morris plot, both film and intraparticle diffusion are involved in controlling the kinetic rate of adsorption for DGA and LN resins.

Characterizing pediatric head patient size in Moroccan population: Establishing age-dependent relationships for accurate CT dose estimation

Accurate dose estimation in computed tomography (CT) scans is crucial and relies on precise normalization of output dose, typically measured by the volume CT dose index (CTDIvol). Key metrics, including effective diameter (Deff) and water-equivalent diameter (Dw), play pivotal roles in characterizing patient size. However, a notable gap exists in delineating the specific relationships between age and head patient size (Deff and Dw) for pediatric patients in Morocco. The primary objective of this study was to establish these critical associations between patient age and head patient size (Deff and Dw), providing a foundation for calculating size-specific dose estimates (SSDE) in pediatric head CT examinations. A retrospective analysis of data from 134 pediatric patients, aged 0–13 yr, comprising 71 males and 63 females who underwent head CT scans, was conducted. Utilizing the Radiant DICOM Viewer, patient sizes were measured in terms of both lateral and anterior-posterior dimensions for Deff and Dw calculations based on CT images in DICOM format. Our analysis revealed robust correlations between patient size (Deff and Dw) and the patient’s age, with R2 values ranging from 0.65 to 0.86. Notably, larger Dw values were consistently observed compared to Deff. For male patients, Deff measurements ranged from 9.02 to 18.77 cm, with Dw values spanning 9.83 to 20.16 cm. Female patients exhibited Deff values ranging from 8.77 to 17.41 cm and Dw values ranging from 8.92 to 18.37 cm. These findings shed light on the crucial relationship between age and patient size, facilitating more precise dose calculations.

Pupils' inclusion as a process of narrative interactions: tackling ADHD typification through MADIT methodology

BackgroundADHD is the most common childhood neurodevelopmental disorder. The symptomatology makes the management of ADHD particularly demanding in school, so teachers’ training programs have been widely implemented. Nevertheless, these interventions could lead teachers to concentrate on the dysfunctional elements of these students, exposing them to the risk of stigmatisation. Conceptualising stigma and inclusion as narrative processes, the present study observed how teacher ADHD training texts, endorsed by the Italian government, impact on the inclusion process of students.MethodsThe research analysed a corpus of N = 31,261 text occurrences and focused on three areas: (1) ADHD as a clinical condition; (2) the impact of ADHD characteristics in the scholastic setting; (3) interventions to manage ADHD criticalities in school settings. To observe the interactive processes fostered by the narratives under scrutiny, we used Dialogic Science and MADIT methodology, since they allow us to measure the language use modalities through an index: the Dialogical Weight (dW). The value of dW ranges between 0.1 (min) and 0.9 (max) and is linked to the potential outcomes of inclusion for students with ADHD. A low dW accounts for narratives entrenched in personal beliefs presented as absolute truths, undermining inclusion of students with ADHD. In contrast, high dW signals language interaction relying on sharable elements, able to foster social unity and diminish stigma.ResultsThe results yielded a critical discursive configuration, both in general and for the three distinct areas. We measured an overall Dialogical Weight of 0.4dW and, for the three areas (1) = 0.3dW; (2) = 0.3dW; (3) = 0.4dW. The analysed text does not maximise the triggering of inclusive interactions, as they rely on individual references and present one’s narrative as the sole plausible perspective: reinforcing already existing positions and exposing to the risk of stereotyping of the pupils.ConclusionsThe study highlighted how the ADHD training materials analysed, focusing on a purely informational and clinical approach, lose in effectiveness with respect to generating inclusive school settings. Finally, to promote the inclusion of these pupils, elements are offered for outlining an approach based on fostering active participation by all roles involved.

Optimization of Pressurized Liquid Extraction (PLE) Parameters for Extraction of Bioactive Compounds from Moringa oleifera Leaves and Bioactivity Assessment.

Moringa oleifera leaves are rich sources of bioactive compounds with potential health benefits, including antioxidants and anti-inflammatory agents. Pressurized liquid extraction (PLE) stands out as a promising technique for effectively extracting valuable compounds from natural sources. In this study, we aimed to optimize PLE parameters, such as temperature, extraction duration, and pressure, to maximize bioactive compound (polyphenols, flavonoids, and ascorbic acid) yield from M. oleifera leaves and evaluate their antioxidant and anti-inflammatory activities. According to the outcomes of this research, the maximum achieved total polyphenol content was 24.10 mg gallic acid equivalents (GAE)/g of dry weight (dw), and the total flavonoid content was increased up to 19.89 mg rutin equivalents (RtE)/g dw. Moreover, after HPLC-DAD analysis, neochlorogenic and chlorogenic acids, catechin and epicatechin, rutin, and narirutin were identified and quantified. As far as the optimum ascorbic acid content is concerned, it was found to be 4.77 mg/g dw. The antioxidant activity was evaluated by three different methods: ferric reducing antioxidant power (FRAP), the DPPH method, and the anti-hydrogen peroxide activity (AHPA) method, resulting in 124.29 μmol ascorbic acid equivalent (AAE)/g dw, 131.28 μmol AAE/g dw, and 229.38 μmol AAE/g dw values, respectively. Lastly, the albumin denaturation inhibition was found to be 37.54%. These findings underscore the potential of PLE as an efficient extraction method for preparing extracts from M. oleifera leaves with the maximum content of bioactive compounds.

Institutional clinical indication-based typical dose values of multiphasic abdominopelvic computed tomography examinations.

Our study aimed to obtain clinical indication-based typical dose values and size-specific dose estimates (SSDEs) for multiphasic abdominopelvic computed tomography (CT) examinations and to review our data with published diagnostic reference levels (DRLs). In this retrospective study, multiphasic liver, kidney, pancreas, and mesenteric ischemia protocol CT scans performed at our center between January 2018 and December 2021 were analyzed. The clinical indications were hepatocellular carcinoma, renal cell carcinoma, pancreas adenocarcinoma, and mesenteric ischemia. The computed tomography dose index volume (CTDIvol) and dose-length product (DLP) values were recorded, and the SSDE and effective dose (ED) values were calculated. The water-equivalent diameter (Dw) value required for the SSDE calculation was measured using the automated calculation of the Dw program. The total number of patients was 514, with 86 patients excluded from this study. The dose values were calculated for 426 patients (183 female and 243 male; 111 liver, 120 kidney, 85 pancreas, and 110 mesenteric). The median values for the CTDIvol, DLP, SSDE, and ED were 6.86 mGy, 683.02 mGy. cm, 8.75 mGy, and 10.45 mSv for the liver CT; 8.37 mGy, 908.37 mGy.cm, 10.37 mGy, and 13.89 mSv for the kidney CT; 7.82 mGy, 517.98 mGy.cm, 10.01 mGy, and 7.92 mSv for the pancreas CT; and 9.48 mGy, 983.68 mGy.cm, 12.78 mGy, and 13.86 mSv for the mesenteric CT, respectively. All dose values were lower than the published DRLs. The literature reveals large differences in the multiphasic abdominopelvic CT protocols, especially in the number of phases and scan length. This situation makes comparing dose values difficult. Dose studies revealing the protocol parameters in detail are needed so that institutions can compare and optimize their own protocols. Additionally, users should periodically check the dose values in their own institutions.

Extraction of Bioactive Compounds from Cistus creticus Leaves and Their Use in the Preparation of Yogurt Desserts

The objective of this study was to determine the optimal conditions for the recovery of bioactive and antioxidant compounds in aqueous solutions of Cistus creticus leaves and then employ the optimal extract for the enrichment of yogurt samples. The optimal conditions were established by a response surface methodology and were determined to be a liquid-to-solid ratio of 48 mL/g at 76 °C for 41 min. The optimum extract yielded TPC 157.17 mg GAE/g dw and TFC 2.38 mg QE/g dw, while FRAP and DPPH values were 1258.52 and 933.67 μmol AAE/g dw, respectively. HPLC-DAD was utilized to identify and quantify specific polyphenols, like myricetin rhamnoside, in the extract. The optimal extract was then added to yogurt desserts during their preparation at three different concentrations to study how the physicochemical characteristics of the yogurt, as well as the antioxidant capacity added during enrichment, were affected. Statistical analysis of the results was carried out in order to obtain more valid data. It seems that the most suitable concentration for yogurt fortification was 0.1% w/v of the extract as, at this concentration, the yogurts exhibited higher antioxidant capacity, and their physicochemical characteristics were improved.

Estimation of size-specific dose estimate (SSDE) of CT scans using an effective diameter electron density

ObjectiveAn assessment of the effective diameter of a patient’s body using electron densities of tissues inside the scan area (Deffρe) was proposed to overcome challenges associated with the estimation of water-equivalent diameter (Dw), which is used for size-specific dose estimate (SSDE). The aims of this study were to (1) investigate the Deffρe method in two different forms using a wide range of patient sizes and scanning protocols, and (2) compare between four methods used to estimate the patient size for SSDE. Materials and methodsUnder IRB approval, a total of 350 patients of varying sizes have been collected retrospectively from the Hospital. The Dw values were assessed over six different CT body protocols: (1) chest with contrast media, (2) chest High-Resolution Computed Tomography (HRCT) without contrast media, (3) abdomen-pelvis with contrast media, (4) abdomen-pelvis without contrast media, (5) chest-abdomen-pelvis with contrast media, and (6) pelvis without contrast media. A MATLAB-based code was developed in-house to assess the size of each patient using the conventional effective diameter method (Deff), Deffρe by correcting either both the lateral (LAT) and anterior-posterior (AP) dimensions (Deff,LAT+APρe) or LAT only (Deff,LATρe), and Dw at the mid-CT slice of the patient images. ResultsThe results of Deff,LAT+APρe and Deff,LATρe provided a better estimation for the chest protocols with the averages of absolute percentage difference (PD) values in the range of 3 – 7 % for all patient sizes as compared to the Dw method, whereas the averages of PD values for the Deff method were 9 – 15 %. However, Deff gave a better estimation for Dw values for the other body protocols, with differences of 2 – 4 %, which were lower than those obtained with the Deff,LAT+APρe and Deff,LATρe methods. For the chest protocols, statistically significant differences were found between Deff and the other methods, but there were no significant differences between all the methods for the other scanning protocols. The results show that the correction of both dimensions, LAT and AP, did not improve the accuracy of the Deffρe method, and, for most protocols, Deff,LAT+APρe gave larger range differences compared to those based on correction of the LAT dimension only. ConclusionIf the Dw cannot be assessed, the Deff,LATρe method may only be considered for the chest protocols as an alternative approach. The Deff method may also be used for all regions taking into account the application of a correction factor for the chest protocols to avoid a significant under or overestimation of the patient dose.

Research on evaluation of fetal right ventricular function in normal and diabetic pregnant women during mid to late pregnancy using automated MPI ultrasound detection technology

Objective: fetal circulatory characteristics differ from those after birth; the right ventricle assumes more than 60% of the workload in the systemic circulation before birth. The right ventricle automated myocardial performance index (AM+MPI) is a simple, time-efficient, and stable assessment method used to evaluate overall cardiac function. This study aimed to apply the right ventricle AM+MPI technique to explore its role in normal mid-to-late pregnancy fetal cardiac function and compare the AM+MPI differences between diabetic and normal fetuses. Methods: A total of 150 pregnant women who visited the obstetric outpatient department at Daxing Hospital, Xi’an, from January 2022 to June 2022 were selected. We excluded 42 patients with comorbid conditions other than diabetes, fetal anomalies, and unclear last menstrual periods, resulting in 85 healthy pregnant patients and 17 diabetic pregnant patients. Using a Samsung WS80A color Doppler ultrasound diagnostic device, we measured the fetal right ventricle AM+MPI, isovolumic contraction time (ICT), isovolumic relaxation time (IRT), and ejection time (ET) in RMPI mode. We performed variability and correlation analyses within the normal group and compared these parameters with those of the diabetic group. Results: In the healthy pregnant group, there was no significant variability in the fetal MPI, ET, or ICT values among the groups (p > 0.05). However, the IRT was positively correlated with gestational age (p < 0.05), with a linear fit formula of IRT = 29.78 + 0.49 × gestational age (DW value 1.87; F = 32.25, p < 0.05), indicating that the IRT increases with gestational age. The right ventricle MPI in the diabetic group was significantly greater than that in the normal group (p < 0.05). Conclusion: The right ventricle AM+MPI technique is simple, time-efficient, and stable and can objectively assess fetal right ventricle function, providing a theoretical basis for the early diagnosis of intrauterine cardiac function abnormalities. Additionally, there are significant differences in the right ventricle MPI between diabetic and normal fetuses, providing evidence for predicting fetal developmental issues and postnatal complications. The right ventricle AM+MPI holds promise as a new method for prenatal evaluation of fetal right heart function.

Determination of water-equivalent diameter (Dw) and size-specific dose estimates (SSDE) for adult patients in abdominal CT examinations

This work aims to calculate size-specific dose estimates (SSDE) and establish the relationship between water equivalent diameter (Dw) values and SSDE in images of abdominal CT examinations undergone by 30 adult patients. These patients had a mean age of 51 years, a mean height of 164 cm, and a mean weight of 62.71 kg. The water equivalent diameters (Dw) measured 25.30 cm on average, with mean volumetric computed tomography dose index (CTDIvol) doses of 7.95 mGy and a mean SSDE of 11.31 mGy. Images were retrospectively collected using a Hitachi Supria 16-slice CT scanner, and Dw and SSDE values were calculated based on lateral and anteroposterior (LAT + AP) measurements of cross-sectional images from each CT examination. Dw was calculated from ED, and their close correspondence allowed for interchangeable use, following AAPM guidelines. The calculated doses (SSDE) were significantly higher than the doses displayed by the scanner (CTDI). Furthermore, a strong correlation (R2 = 0.63) was observed between SSDE and Dw. Consequently, assessing patient dose based on size becomes essential to optimize radiation exposure in CT imaging.

Modernization of Intellectual Property Discipline Governance Based on Multivariate Statistical Analysis Towards the Construction of a Powerful Intellectual Property Country

Abstract In this paper, after using the TF-IDF algorithm to calculate the weights of intellectual property keywords of digital content, the weights of fused word multi-features are improved to obtain the proportion of intellectual property keywords. Based on intellectual property keywords, combining adversarial fingerprint generation and intellectual property authentication, an intellectual property protection model based on RCNN is constructed. From the perspective of strong nation-building, the research on intellectual property affecting the artificial intelligence industry is designed, and multivariate statistical analysis of scientific governance of intellectual property in the context of strong nation-building is carried out. The results show that the SSIM values obtained by the method of this paper are much better than those obtained by the comparison method in terms of model analysis. Except for the anti-quantization attack, the rest of the indicators are all greater than 0.9. It confirms that the method presented in this paper has excellent robustness in protecting intellectual property. In the empirical analysis of the impact of intellectual property rights on the artificial intelligence industry, except for RDF, which is significant at the 5% level, the regression coefficients of the other explanatory variables are all significant at the 1% level, 2 R amounting to 0.860771 and with a DW value of 1.667387 in the range of 1.5-2.5, that is, it indicates that the level of China’s intellectual property rights protection and the competitiveness of the AI industry are positively correlated. It is positively correlated. This study promotes the improvement of China’s innovation ability and the formation of innovation mechanisms from the aspect of intellectual property protection so as to realize the comprehensive catching up of technology and economy of late-developed countries.

Laboratory Study of Fortin Pro25 WP Efficacy Against Seed Rot and Seedlings Death Causes Rhizoctonia solani and Pythium spp.

The objective of this study was to ascertain the fungal species responsible for inducing seed rot illnesses and seedling mortality in okra plants, a prevalent issue throughout many parts in Al-Muthanna governorate. The objective of this study was to assess the efficacy of the fungicide Fortin Pro25WP in inhibiting the growth and biomass of the pathogenic fungus R. solani and Pythium spp in vitro, using various mediums. The findings from the process of isolation, phenotypic characterization, and molecular identification indicate that the samples of deceased and diseased okra seedlings were linked to the presence of R. solani and Pythium spp. The results also showed the high pathogenic ability of the two fungi in reducing percentage of okra seeds germintion, especially R. solani, which did not allow any seed to germinate on the culture media, while Pythium spp. reduced germination rate from 100% in the control treatment to 68.33%. The study also showed that the fungicide showed high efficiency in inhibiting the growth of pathogenic fungi by 77.78% and 89.78% for R. solani and Pythium spp. respectively. The fungal biomass was reduced by estimating the fresh weight FW and dry weight DW, with percentages ranging from 75-92% of the FW and 74-86% of the DW value of both fungi, respectively, on the PDB liquid medium.

Time-Warping Analysis of the T-Wave Peak-to-End Interval to Quantify Ventricular Repolarization Dispersion During Ischemia.

The presence of myocardial ischemia can increase ventricular arrhythmic risk due to a raised dispersion of ventricular repolarization. This is reflected on the morphology of the T-wave on the electrocardiogram (ECG), and can be quantified by time-warping based indexes, like dw. However, T-wave morphology can also be affected by ischemia-induced ST segment changes, impacting the accuracy of dw. We hypothesize that ischemia-induced repolarization dispersion can be better quantified by restricting dw to the T-wave peak-to-end (T pe) interval. 101 ECG recordings from patients undergoing a percutaneous coronary intervention (PCI) were analyzed together with their control ECG recordings, acquired before the intervention. A series of dw values was calculated by quantifying the T pe morphological variations between the T-waves from the PCI and a reference derived from the control ECG recordings. We proposed a normalized version of dw, Rd, reflecting relative variations of dw during PCI to control recordings, and compare it with traditional indices behaviour. Values of dw followed a gradually increasing trend as PCI inflation time progressed, reaching a median[range] Rd value of 9.44 [1.01, 80.74] at the occlusion end. During control recordings, dw remained stable, with a low intra-patient standard deviation, range [0.02, 2.09] ms and a median[range] Rd of 1.00 [0.03, 2.93]. Rd at oclussion end was significantly higher than threshold values of 1, 2, 5, and 10 in 94.1%, 85.11%, 64.4% and 48.5% of patients, respectively. The spatial lead-wise analysis of dw showed distinct distributions depending on the occluded artery, suggesting a relation with the ischemia location. The relative variation R with ischemia of index dw (9.4) is greater than for traditional T wave amplitude (7.7), T peak-to-end interval (2.7) and T width (3.0). The index dw, quantifying T pe morphology variations, allows to follow the ischemia induced variations in repolarization in a more robust manner than classical indexes, avoiding ST segment and early T wave distortions not related to repolarization dispersion, and warranting further clinical studies to evaluate its ventricular arrhythmia risk predictive value during ischemia.

Изучение принципов построения широкополосной колебательной СВЧ системы на примере резонатора Фабри-Перо

In telecommunications and radar systems of the centimeter and millimeter wave ranges, span klystrons are widely used as medium and high power amplifiers. The use of high-quality resonators makes it possible to realize high efficiency and amplification factors. However, typical designs of 2 - 4 resonator klystrons have a bandwidth of 0.1 - 0.5 % due to the need to use resonators with a high Q – factor. The well-known method of expanding the amplified frequency band in the centimeter range up to 7 – 12 % and in the millimeter range up to 1 - 2 % consists in tuning the frequency of the intermediate klystron resonators by several percent of the central amplification frequency. But in this case, it is required to use 10 - 12 resonators. The authors of the work discovered that when a millimeter range electromagnetic wave is reflected from an electrodynamics system in the form of a metal film on the surface of a semiconductor layer, the input resistance phase-frequency characteristic of this system consists of a chain of frequency intervals with turnings from a positive phase-frequency characteristic to a negative one and vice versa. The possibility of constructing a phase shifter with a negative phase frequency response based on this phenomenon is demonstrated and its application for expanding the resonant frequency band is considered on the example of the Fabry - Perot interferometer model. This resonator contains a phase shifter in the form of a semiconductor layer F with a thickness DF, a conductivity σF, a relative dielectric eF and a magnetic mF permeability. The outer surface of the layer F contains a metal mirror, and the inner surface is adjacent to the layer W. The layer W which has the thickness of DW, eW, mW forms the internal space of the resonator. The external environment I with mI and eI. adjoins the layer W. A plane electromagnetic wave propagates in I media so that it excites the resonator at a wavelength of l0. The use of a phase shifter makes it possible to increase the resonant wavelength band Δl/l0 by 2 - 4 times and with an electromagnetic field amplification coefficient |G(l)| in the W layer by 10 - 20 times (the value of Dl/l0 corresponds to 0.707 max |G(l0)|). An increase of σF leads to an amplitude-frequency characteristic transforming of the field gain function G(l0) from two maxima to one maximum form with a transition through a flat top. In this case max |G(l0)| decreases and Dl/l0 increases. For the case, when the function |G(l)| has a flat top, an increase in the wave resistance ρW of the layer W with a corresponding decrease in sF and optimal values of DW leads to an increase in |G(l0)|. When this occurs, Dl/l0 becomes lower.

Organ dose in CT: Comparison between measurements and computational methods

PurposeThis study aims to compare two methods for the organ dose evaluation in computed tomography (CT) in the head- and thorax regions: an experimental method, using radiochromic films, and a computational one, using a commercial software. MethodsGafchromic® XR-QA2 and EBT-3 were characterized in terms of energetic, angular, and irradiation configurations dependence. Two free-in-air irradiation calibration configurations were employed using a CT scanner: with the sensitive surface of the film orthogonal (OC) and parallel (PC) to the beam axis. Different dose–response curves were obtained by varying the irradiation configurations and the beam quality (BQ). Subsequently, films were irradiated within an anthropomorphic phantom using CT-thorax and -head protocols, and the organ dose values obtained were compared with those provided by the commercial software. ResultsAt different configurations, an unchanged dose response was achieved with EBT-3, while a dose response of 15% was obtained with XR-QA2. By varying BQ, XR-QA2 showed a different response below 10%, while EBT-3 showed a variation below 5% for dose values >20 mGy. For films irradiation angle equal to 90°, the normalized to 0° relative response was 41% for the XR-QA2 model and 83% for the EBT-3 one. Organ dose values obtained with EBT-3 for both configurations and with XR-QA2 for OC were in agreement with the DW values, showing percentage discrepancies of less than 25%. ConclusionsThe obtained results showed the potential of EBT-3 in CT patient dosimetry since the lower angular dependence, compared to XR-QA2, compensates for low sensitivity in the diagnostic dose range.

Numerical study of the effect of axial cyclone inlet velocity and geometrical parameters on separation efficiency and pressure drop

The effects of cyclone separation length lm, outlet pipe inner diameter dw and swirl guide angle β were numerically studied for different inlet velocities: 2.5 m/s, 5 m/s, 7.5 m/s, 10 m/s in four cyclone models, using Ansys Fluent software. The fractional composition of the test dust was considered using the Rosin- Rammler model. Four cyclone models were tested for velocities in the range of 2.5–10 m/s and five particle size ranges. The mass proportion of particles in the cyclone and the filtration efficiency were determined, which is a novel method for evaluating cyclones. The lowest filtration efficiency, regardless of the cyclone model, was found, for particles in the 0–5 μm range, and the highest in the 20–40 μm range. Better results were obtained for higher values of lm smaller dw and β = 90o. Optimal performance and the highest value of the filtration quality factor is obtained by cyclone model B for υ0 = 5–10 m/s.

An in-house step-wedge phantom for the calibration of pixel values in CT localizer radiographs for water-equivalent diameter measurement

Abstract Introduction: To develop an in-house acrylic-based step-wedge phantom with several thickness configurations for calibrating computed tomography (CT) localizer radiographs in order to measure the water-equivalent diameter (Dw) and the size-specific dose estimate (SSDE). Method: We developed an in-house step-wedge phantom using 3 mm thick acrylic, filled with water. The phantom had five steps with thicknesses of 6, 12, 18, 24, and 30 cm. The phantom was scanned using a 64-slice Siemens Definition AS CT scanner with tube currents of 50, 100, 150, 200, and 250 mA. The relationship between pixel value (PV) and water-equivalent thickness (tw) was obtained for the different step thicknesses. This was used to calibrate the CT localizer radiographs in order to measure Dw and SSDE. The results of Dw and SSDE from the radiographs were compared with those calculated from axial CT images. Results: The relationship between PV and tw from CT localizer radiographs of the phantom step-wedge produced a linear relationship with R2 &gt; 0.990. The linear relationships of the Dw and SSDE values obtained from CT localizer radiographs and axial CT images had R2 values &gt; 0.94 with a statistical test of p-value &gt; 0.05. The Dw difference between those from CT localizer radiographs and axial CT images was 3.7% and the SSDE difference between both was 4.3%. Conclusion: We have successfully developed a step-wedge phantom to calibrate the relationship between PV and tw. Our phantom can be easily used to calibrate CT localizer radiographs in order to measure Dw and SSDE.

Comparison of Water-Equivalent Diameter Measured from CT Localizer Radiograph Based on Two phantoms of the Step-Wedge and Computed Tomography Dose Index

The purpose of this study is to compare the water-equivalent diameter (Dw) and size-specific dose estimate (SSDE) obtained from CT localizer radiograph based on the step-wedge and computed tomography dose index (CTDI) phantoms. The two phantoms were scanned using a 64-slice SIEMENS Somatom CT Scanner with tube currents of 100 mA and 120 kV. The CT localizer radiographs of two phantoms were obtained. Subsequently, relationships between pixel values (PV) and water-equivalent thickness (tw) were developed. Based on those relationships, the Dw and SSDE of twenty patients were calculated from the CT localizer radiographs. The results of the Dw and SSDE measured using CT localizer radiographs based on the two phantoms were compared. The relationships between PV and tw obtained from both CT localizer radiographs of the phantoms of step-wedge and CTDI are established. The Dw and SSDE values from the CT localizer radiograph calibrated with the CTDI phantom and step-wedge phantom also have linear relationship with R2 &gt; 0.99. The statistical test value with p-value &gt; 0.05 indicating that the two measurements of Dw and SSDE based on two phantoms are not statistically different. The results from the step-wedge phantom are comparable with those from the CTDI phantom. The relationship PV and tw with CT localizer radiograph from the step-wedge phantom can produce accurate calibration results. The results of the calibration of the step-wedge phantom can then determine the value of Dw and SSDE.

Mathematical model and reaction mechanism of molybdenum and tungsten extraction with TRPO from peroxide solution

To understand the behavior of molybdenum and tungsten extracted by tri-alkyl phosphine oxide (TRPO) from peroxide solution, the extraction mechanism was studied by slope method and Raman and FTIR spectroscopy. The empirical formulas of molybdenum and tungsten extraction distribution ratio (DMo and DW) as functions of equilibrium pH, TRPO concentration and temperature were obtained by establishing mathematical models. Furthermore, the reliability of the empirical formula was verified in the H+−W−Mo−H2O2 solution. The results indicate that the calculated values of DMo or DW were consistent with the experimental values. The apparent extraction equilibrium constants of molybdenum and tungsten were =8.51×103 (0.74≤pHe≤1.7), =99.89×103 (1.7<pHe≤4.62) and =2.65×103 (0.92<pHe<2.16) at 20 °C, respectively. The main extraction complex of molybdenum or tungsten was [H2(Mo or W)2O3(O2)4(H2O)2]·2TRPO. These empirical formulas can be used to analyze and estimate the extraction and separation of Mo and W from low molybdenum and tungsten concentration solutions.

Pengaruh Profitabilitas, Kepemilikan Publik, Opini Publik Dan Ukuran Perusahaan Terhadap Ketepatan Waktu Pelaporan Keuangan Perusahaan Di Bursa Effek Indonesia

The purpose of this study was to determine the effect of profitability, public ownership, public opinion and company size on the timeliness of company financial reporting on the Indonesian Stock Exchange. The objects taken in this study are ten sub-sectors of companies listed on the Indonesia Stock Exchange (IDX) which are grouped into two categories based on the timeliness of the company's financial reporting for the period 2016, 2017, and 2018, namely: Companies that are timely in their financial reporting to Bapepam -LK, and companies that are not timely in their financial reporting to Bapepam-LK. The variables used in this study can be classified into two, namely: Dependent Variables, In this study the dependent variable is timeliness (Y). Independent Variables (Independent Variables). In this study the independent variables are Profitability (X1), Public Ownership (X2), Audit Opinion (X3), and Company Size (X4). Based on the output results above, the DW value generated from the regression model is 1.936. The amount of data (n) = 30, seta k = (5) (k is the number of independent variables) obtained the value of du of 1.835 and dL of 1.071. Then the autocorrelation value is between 1.835 &lt; 1.936 &lt; 2.165 so there is no autocorrelation.