194 research outputs found

    PRAĆENJE KRETANJA GRANICE DVAJU FLUIDA U ZONI RASJEDA I DISKONTINUITETA S HETEROGENOM PROPUSNOŠĆU

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    Fluid front tracking is important in two-phase/component fluid flow in porous media with different heterogeneities, especially in the improved recovery of oil. Three different flow patterns of stable, viscous fingering, and capillary fingering exist based on the fluids’ viscosity and capillary number (CA). In addition, fluid front and sweep efficiency are affected by the heterogeneity of the porous medium. In the current study, the heterogeneous porous media are: (1) normal fault zone or cross-bedding with heterogeneity in permeability, and (2) a fracture or discontinuity between two porous media consisting of two homogeneous layers with very low and high permeabilities, in which immiscible water flooding is performed for sweep efficiency and streamlines tracking purposes. By considering the experimental glass micromodel and the simulation results of discontinuity, a crack is the main fluid flow path. After the breakthrough, fluid inclines to penetrate the fine and coarse grains around the crack. Moreover, an increase in flow rate from 1 and 200 (ml/h) in both the experimental and simulation models causes a reduction in the sweep efficiency from 14% to 7.3% and 15.6% to 10% by the moment of breakthrough, respectively. In the fault zone, the sweep efficiency and the streamline of the injected fluid showed a dependency on the interface incident angle, and the layers’ permeability. The presented glass micromodel and Lattice Boltzmann Method were consistent with fluid dynamics, and both of them were suitable for a precise evaluation of sweep efficiency and visualization of preferential pathway of fluid flow through cross-bedding and discontinuity for enhanced oil recovery purposes.Praćenje kretanja granice dvaju fluida vrlo je važno kod protjecanja dviju faza u poroznoj heterogenoj sredini, osobito kod primjene metoda povećanja iscrpka nafte. S obzirom na viskoznost fluida i kapilarni broj moguća su tri različita oblika toka: stabilni te viskozno i kapilarno probijanje. Dodatno, granica fluida i koeficijent obuhvata ležišta istiskivanjem ovise i o heterogenosti porozne sredine. U ovome istraživanju heterogena porozna sredina predstavljena je (1) zonom normalnoga rasjeda ili unakrsne slojevitosti s heterogenom propusnošću i (2) frakturom ili diskontinuitetom između dviju poroznih sredina koja se sastoji od dvaju homogenih slojeva s vrlo niskom i vrlo visokom propusnošću, u kojoj je izvedeno nemješljivo zavodnjavanje kako bi se promatrao koeficijent obuhvata ležišta istiskivanjem i pratilo strujnice toka fluida. Razmatranjem eksperimentalnoga staklenog mikromodela i rezultata simulacije diskontinuiteta utvrđeno je da glavni tok fluida prati pukotinu. Nakon proboja fluid nastoji prodrijeti i kroz međuprostor sačinjen od finih i grubih čestica uokolo pukotine. Štoviše, povećanjem protoka s 1 na 200 ml/h, i kod eksperimentalnoga i kod simulacijskoga modela, došlo je do smanjenja koeficijenta obuhvata ležišta istiskivanjem do trenutka proboja s 14% na 7,3% odnosno s 15,6% na 10%. U zoni rasjeda uočena je ovisnost koeficijenta obuhvata ležišta istiskivanjem i strujnica utisnutoga fluida o upadnome kutu na površinu rasjeda i propusnosti slojeva. Prezentirani stakleni mikromodel i rešetkasti Boltzmannov model bili su u skladu s dinamikom fluida i oba se mogu koristiti za preciznu ocjenu koeficijenta obuhvata ležišta istiskivanjem i vizualizaciju preferiranoga puta kretanja fluida kroz područja unakrsne slojevitosti ili diskontinuiteta kod metoda povećanja iscrpka nafte

    Whole-body voxel-based internal dosimetry using deep learning

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    In the era of precision medicine, patient-specific dose calculation using Monte Carlo (MC) simulations is deemed the gold standard technique for risk-benefit analysis of radiation hazards and correlation with patient outcome. Hence, we propose a novel method to perform whole-body personalized organ-level dosimetry taking into account the heterogeneity of activity distribution, non-uniformity of surrounding medium, and patient-specific anatomy using deep learning algorithms

    DeepTOFSino:A deep learning model for synthesizing full-dose time-of-flight bin sinograms from their corresponding low-dose sinograms

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    Purpose: Reducing the injected activity and/or the scanning time is a desirable goal to minimize radiation exposure and maximize patients’ comfort. To achieve this goal, we developed a deep neural network (DNN) model for synthesizing full-dose (FD) time-of-flight (TOF) bin sinograms from their corresponding fast/low-dose (LD) TOF bin sinograms.Methods: Clinical brain PET/CT raw data of 140 normal and abnormal patients were employed to create LD and FD TOF bin sinograms. The LD TOF sinograms were created through 5% undersampling of FD list-mode PET data. The TOF sinograms were split into seven time bins (0, ±1, ±2, ±3). Residual network (ResNet) algorithms were trained separately to generate FD bins from LD bins. An extra ResNet model was trained to synthesize FD images from LD images to compare the performance of DNN in sinogram space (SS) vs implementation in image space (IS). Comprehensive quantitative and statistical analysis was performed to assess the performance of the proposed model using established quantitative metrics, including the peak signal-to-noise ratio (PSNR), structural similarity index metric (SSIM) region-wise standardized uptake value (SUV) bias and statistical analysis for 83 brain regions.Results: SSIM and PSNR values of 0.97 ± 0.01, 0.98 ± 0.01 and 33.70 ± 0.32, 39.36 ± 0.21 were obtained for IS and SS, respectively, compared to 0.86 ± 0.02and 31.12 ± 0.22 for reference LD images. The absolute average SUV bias was 0.96 ± 0.95% and 1.40 ± 0.72% for SS and IS implementations, respectively. The joint histogram analysis revealed the lowest mean square error (MSE) and highest correlation (R2 = 0.99, MSE = 0.019) was achieved by SS compared to IS (R2 = 0.97, MSE= 0.028). The Bland &amp; Altman analysis showed that the lowest SUV bias (-0.4%) and minimum variance (95% CI: -2.6%, +1.9%) were achieved by SS images. The voxel-wise t-test analysis revealed the presence of voxels with statistically significantly lower values in LD, IS, and SS images compared to FD images respectively.Conclusion: The results demonstrated that images reconstructed from the predicted TOF FD sinograms using the SS approach led to higher image quality and lower bias compared to images predicted from LD images.</p

    Evaluation of the expression of Hottip long noncoding RNA in the B16F10 murine melanoma cell line

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    زمینه و هدف: ملانوما یکی از انواع سرطان پوست است که نسبت به سایر سرطان های پوست خطرناک تر می باشد. یکی از عوامل موثر در ایجاد سرطان ها، گروهی از RNA های غیر کد کننده اند که به نام lncRNA (long noncoding RNA) شناخته می شوند. این مولکول های غیر کد کننده بیش از 200 باز طول دارند و به عنوان یک تنظیم کننده در پیشرفت سرطان عمل می کنند Hottip (HOXA transcript at the distal tip) یک lncRNA ی بین ژنی است که از انتهای '5 لوکوس Hoxa رونویسی می شود و ژن های انتهای '5 این لوکوس را فعال می کند. هدف از این مطالعه، بررسی میزان بیان این مولکول RNA در رده ی سلولی B16F10 ملانومای موشی بود. روش بررسی: در این مطالعه بیان ژن Hottip با انجام تکنیک RT-PCR به صورت کیفی روی رده ی سلولی B16F10 ملانومای موشی بررسی شد. بدین منظور، از رده ی سلولی، RNA کل استخراج و سنتز cDNA انجام گرفت. با استفاده از پرایمرهای اختصاصی طراحی شده، ژن های Hottip و &beta;2m تکثیر گردیدند. یافته ها: نتیجه مطالعه حاضر نشان دهنده ی عدم بیان ژن Hottip موشی در رده ی سلولی B16F10 ملانومای موشی است. نتیجه گیری: در حالی که بر اساس مطالعات صورت گرفته در سرطان های انسانی انتظار می رفت Hottip افزایش بیان داشته باشد، Hottip موشی در رده ی سلولی B16F10 ملانومای موشی بیانی نشان نداد

    The effects of low intensity aerobic exercise on blood pressur

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    چکیده: زمینه و هدف: کاهش فعالیتهای جسمی (کم تحرکی) و پرفشاری خون هر دو از عوامل خطر در ایجاد بیماریهای قلبی و عروقی و سکته های مغزی می باشند. کنترل فشارخون در محدوده طبیعی می تواند از ایجاد این عوارض پیشگیری کند یا آنها را به تعویق اندازد. استفاده از روشهای غیر دارویی یکی از اقدامات مهم در کنترل فشارخون می باشد. این مطالعه با هدف بررسی تأثیر ورزش پیاده روی با شدت پایین بر فشارخون کارمندان مبتلا به پرفشاری خون اولیه، انجام شد. روش بررسی: پژوهش حاضر یک مطالعه نیمه تجربی است که در آن 36 کارمند مبتلا به پرفشاری خون اولیه مراجعه کننده به مراکز بهداشتی درمانی شهر بروجن در یک برنامه ورزشی پیاده روی با شدت پایین به مدت 4 هفته، هر هفته 3 بار و هر بار به مدت 30-20 دقیقه شرکت کردند. سرعت پیاده روی در حدی تعیین شد که ضربان قلب در محدوده 60-50 درصد حداکثر ضربان قلب باشد. قبل از ورود به برنامه ورزشی، بلافاصله بعد از آن و یک هفته بعد متغیرهای پژوهش (فشارخون، نبض، وزن و شاخص توده بدنی) مورد اندازه گیری قرار گرفتند. داده ها با استفاده از آزمونهای آماری t زوجی و آنالیز واریانس با اندازه گیری‌های مکرر تجزیه و تحلیل شدند. یافته ها: میانگین سنی واحدهای مورد پژوهش 5±13/46 سال بود. قبل و پس از مداخله به ترتیب میانگین فشارخون سیستولیک 12±04/150 و 11±5/149 (05/0p>)، فشارخون دیاستولیک 6±6/88 و 5±6/84 (001/0

    Obstacles of Women Presence in Iranian Rural Management: A Case from Osku County

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    The presence of women in social and managerial fields is one the indicator of social justice and development that leads to optimum use of capabilities and potentials of half of the country’s rural population. In the recent years, establishing public institution of Dehyary by the Ministry of Interior have provided new opportunity for women presence in rural management. This study aimed to identify women’s participation obstacles in rural management in Iran, specifically in Dehyary. The statistical population of this study was 15-64 year – old females which were resident in rural areas of Oskou County. Applying a proportional random sampling and Cochran formula, 347 women were chosen to be surveyed as sample. A questionnaire was used for data collection, which its face validity was approved by a panel of experts and its reliability was calculated by Cronbach’s alpha coefficient (α=0.84). The results revealed that, negative attitudes and believes in rural community is the most important obstacle for women to participate in rural management. Furthermore, factor analysis categorized obstacles for women participation in six factors including cultural, personal, supportive, job-related, religious and Economic constrains

    Exploitation of resources and cardiovascular outcomes in low-risk patients with chest pain hospitalized in coronary care units

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    Habibollah Saadat&amp;sup1;, Hossein Shiri&amp;sup2;, Zahra Salarpour&amp;sup2;, Tahereh Ashktorab&amp;sup2; , Hamid Alavi Majd&amp;sup2;, Zahra Saadat&amp;sup1;, Hosein Vakili&amp;sup1; 1Cardiovascular Research Center, Modarres Hospital, Shaheed Beheshti University of Medical Sciences, Tehran; 2Nursing School, Shaheed Beheshti University of Medical Sciences, Tehran, Iran Background: Most patients who present to medical centers due to chest pain do not suffer from acute coronary syndromes and do not need to be hospitalized in coronary care units (CCUs). This study was done to determine exploitation of resources and cardiovascular outcomes in low-risk patients with chest pain hospitalized in CCUs of educational hospitals affiliated with a major medical university. Methods: Over a 4-month period, 550 patients with chest pain who were hospitalized in the CCUs belonging to six hospitals affiliated to the authors&amp;#39; medical university were recruited by census method. Using Thrombolysis in Myocardial Infarction risk score, 95 patients (17.27%) were categorized as low-risk patients. This group was evaluated with respect to demographics, bed occupancy rate, mean hospitalization period, expenses during admission, and cardiovascular outcomes in the 30-day period postdischarge. Results: Mean (&amp;plusmn; standard deviation) hospitalization duration was 3.04 (&amp;plusmn;0.71) days. No significant difference was seen between the six surveyed hospitals regarding hospitalization duration (P = 0.602). The highest bed occupancy rate was seen in Taleghani and Shohada Tajrish hospitals and the lowest was in Modarres Hospital. The mean paid treatment expenses by low-risk patients was IRR 2,050,000 (US205).MeantotalhospitalizationexpenseswasUS205). Mean total hospitalization expenses was US205. No significant difference was seen between the six surveyed hospitals (P = 0.699). Of the patients studied, 89.5% did not show any cardiovascular complications in 1 month and no deaths occurred. Conclusion: Given the high bed-occupancy rate by low-risk patients, associated high hospitalization costs, and the lack of cardiovascular complications in patients observed at 1-month follow-up after discharge, it is recommended that appropriate evaluations be performed in emergency units to prevent unnecessary admissions. Keywords: bed occupancy, hospitalization expenses, low-risk patients, chest pain, exploitation of resource

    High Seroprevalence of Anti-H. pylori Antibodies in Patients with Ventilator Associated Pneumonia

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    Background: Despite major advances in the management of ventilator-associated pneumonia, its pathogenesis is not clearly known. Recently, the role of gastric colonization has been proposed. We compared the prevalence of H. pylori by serology in patients with VAP and in control subjects to determine the role of H. pylori and gastric colonization in the pathogenesis of VAP. Methods:118 intubated and mechanically ventilated patients were included and divided into two groups; 59 subjects with VAP and 59 control patients. Results of the serologic tests, demographic characteristics and time of blood sampling were registered. Results: Mean age in seropositive patients was significantly higher. 71.2% in the VAP group and 61.01% in controls were IgG seropositive (P=0.24). IgM seropositivity was 23.73% versus 8.47% in VAPs and controls, respectively (P=0.024). By increasing the time of intubation, more patients became seropositive for IgM (Pearson’s correlation coefficient=0.4, P=0.002). Conclusion:  IgM seropositivity and serum level were significantly higher in VAP patients. Also by increasing the duration of intubation and time of sampling, serum levels and seropositivity for IgM increased significantly

    The Relationship between Sleep Quality and Happiness in Men with Coronary Artery Disease

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    Background and Aim: Good sleep quality has beneficial effects on happiness and being unhappy is significantly associated with negative cardiac outcomes. The present research aimed at studying the relationships between sleep quality and happiness in male coronary patients. Methods: One hundred male coronary patients that having been referred to Madani Heart Hospital, Tabriz, Iran, completed the Pittsburgh Sleep Quality Index (PSQI) and Oxford Happiness Questionnaire (OHQ). All participants were selected by purposive sampling (aged 37 to 67 years). Data were analyzed by multiple regression (simultaneous method) through the SPSS 18 software.Results: There was a significant negative difference between happiness with sleep disturbances and use of sleeping medication in coronary patients. Conclusion: This study showed that poor sleep quality in coronary patients has negative effects on their happiness. Therefore, the quality of sleep in these patients should be given more consideration by community health care providers.Keywords: Sleep Quality, Happiness, Coronary Artery Disease

    Impact of feature harmonization on radiogenomics analysis:Prediction of EGFR and KRAS mutations from non-small cell lung cancer PET/CT images

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    Objective: To investigate the impact of harmonization on the performance of CT, PET, and fused PET/CT radiomic features toward the prediction of mutations status, for epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene (KRAS) genes in non-small cell lung cancer (NSCLC) patients. Methods: Radiomic features were extracted from tumors delineated on CT, PET, and wavelet fused PET/CT images obtained from 136 histologically proven NSCLC patients. Univariate and multivariate predictive models were developed using radiomic features before and after ComBat harmonization to predict EGFR and KRAS mutation statuses. Multivariate models were built using minimum redundancy maximum relevance feature selection and random forest classifier. We utilized 70/30% splitting patient datasets for training/testing, respectively, and repeated the procedure 10 times. The area under the receiver operator characteristic curve (AUC), accuracy, sensitivity, and specificity were used to assess model performance. The performance of the models (univariate and multivariate), before and after ComBat harmonization was compared using statistical analyses. Results: While the performance of most features in univariate modeling was significantly improved for EGFR prediction, most features did not show any significant difference in performance after harmonization in KRAS prediction. Average AUCs of all multivariate predictive models for both EGFR and KRAS were significantly improved (q-value &lt; 0.05) following ComBat harmonization. The mean ranges of AUCs increased following harmonization from 0.87-0.90 to 0.92-0.94 for EGFR, and from 0.85-0.90 to 0.91-0.94 for KRAS. The highest performance was achieved by harmonized F_R0.66_W0.75 model with AUC of 0.94, and 0.93 for EGFR and KRAS, respectively. Conclusion: Our results demonstrated that regarding univariate modelling, while ComBat harmonization had generally a better impact on features for EGFR compared to KRAS status prediction, its effect is feature-dependent. Hence, no systematic effect was observed. Regarding the multivariate models, ComBat harmonization significantly improved the performance of all radiomics models toward more successful prediction of EGFR and KRAS mutation statuses in lung cancer patients. Thus, by eliminating the batch effect in multi-centric radiomic feature sets, harmonization is a promising tool for developing robust and reproducible radiomics using vast and variant datasets.</p
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