Effect of Density on Critical Depth of Liquefaction in a Soil Deposit Containing Double Loose Sand Lenses

Large surface deformations due to liquefaction have been observed in many soil deposits which seem to feature good geotechnical characteristics. These deformations are often caused by the liquefaction of sand layers surrounded by clayey or silty soils called “sand lenses”. Liquefaction potential often decreases with increasing of depth. Hence, a specific depth of embedment of the lenses can be defined below which liquefaction would unlikely happen or the consequential surface deformation would be negligible. This depth is called critical depth. This research aims at studying the effects of the relative density of the sand within the lenses on the critical depth of liquefaction in a soil deposit containing double sand lenses. The soil deposit is simulated in plane strain condition using the computer code, FLAC (Version 4), which is based on finite difference method. Soil deformation, hysteresis loops, shear strain, shear stress, pore water pressure and effective stress in the sand lenses have been plotted during seismic loading. Results indicate that critical depth is strongly dependent on the relative density of the sand. The rate of change of the critical depth versus the standard penetration test number decreases with increasing relative density

Evaluation of suspicious appearing microcalcification groups on mammogram: Comparing BI-RADS 5th edition descriptors with the BI-RADS 4th edition and pathologic association

Background: Groups of microcalcifications are the most frequent recognized features of ductal carcinoma on mammograms. However, heterogeneity (in size, morphology and density) and number of microcalcification groups as well as presence of accompanied soft-tissue density are not included in breast imaging reporting and data system (BI-RADS) descriptors. Objectives: The study purposes to determine the malignancy risk of microcalcification groups regarding these characteristics and also compare the 4th and 5th versions of BI-RADS. Patients and Methods: In a cross sectional study, 88 patients with microcalcification groups (age range, 26-80 years; mean, 53.4 years) who had undergone mammographically guided biopsy between March 2013 and March 2015 were evaluated. The overall number of microcalcification groups in each patient, number of deposits within each group, group location and heterogeneity in size, density and morphology were assessed and subsequently BI-RADS descriptors for 4th and 5th editions were recorded separately. Finally, correlation with histopathology was performed. Results: Overall, positive predictive value (PPV) of suspicious microcalcifications was 22.4. PPVs of morphology descriptors were as follows: amorphous, 7.9; coarse heterogeneous, 17.8; fine pleomorphic, 63.2; fine linear/fine linear branching, 100; (P < 0.001). Heterogenicity in size existed in 81 cases (92), in density in 69 cases (86.4) and in morphology in 86 cases (97.7). Additionally, microcalcification groups that were accompanied with soft-tissue density had a higher percentage of malignancy (67.5 vs. 54.5) but with no significant difference (P = 0.2). According to BI-RADS 4th edition, the risk of malignancy was 49.1, 66.7 and 88.1 in 4b, 4c and 5, respectively. These figures were 30, 82.9, and 100 for BI-RADS 5th version, respectively. The area under the receiver (AUC) of 4th and 5th versions of BI-RADS was 0.76 and 0.74 (both P values < 0.001, 95 confidence intervals = 0.66-0.87 and 0.63-0.85 respectively). P value for comparison was insignificant. Conclusion: The risk of malignancy increased with the heterogeneity of microcalcifications, especially in the groups with heterogeneity in density, however with no statistically significant difference. BI-RADS 5th edition could predict the likelihood of malignancy as well as 4th version. © 2018, Iranian Journal of Radiology

Evaluation of suspicious appearing microcalcification groups on mammogram: Comparing BI-RADS 5th edition descriptors with the BI-RADS 4th edition and pathologic association

Background: Groups of microcalcifications are the most frequent recognized features of ductal carcinoma on mammograms. However, heterogeneity (in size, morphology and density) and number of microcalcification groups as well as presence of accompanied soft-tissue density are not included in breast imaging reporting and data system (BI-RADS) descriptors. Objectives: The study purposes to determine the malignancy risk of microcalcification groups regarding these characteristics and also compare the 4th and 5th versions of BI-RADS. Patients and Methods: In a cross sectional study, 88 patients with microcalcification groups (age range, 26-80 years; mean, 53.4 years) who had undergone mammographically guided biopsy between March 2013 and March 2015 were evaluated. The overall number of microcalcification groups in each patient, number of deposits within each group, group location and heterogeneity in size, density and morphology were assessed and subsequently BI-RADS descriptors for 4th and 5th editions were recorded separately. Finally, correlation with histopathology was performed. Results: Overall, positive predictive value (PPV) of suspicious microcalcifications was 22.4. PPVs of morphology descriptors were as follows: amorphous, 7.9; coarse heterogeneous, 17.8; fine pleomorphic, 63.2; fine linear/fine linear branching, 100; (P < 0.001). Heterogenicity in size existed in 81 cases (92), in density in 69 cases (86.4) and in morphology in 86 cases (97.7). Additionally, microcalcification groups that were accompanied with soft-tissue density had a higher percentage of malignancy (67.5 vs. 54.5) but with no significant difference (P = 0.2). According to BI-RADS 4th edition, the risk of malignancy was 49.1, 66.7 and 88.1 in 4b, 4c and 5, respectively. These figures were 30, 82.9, and 100 for BI-RADS 5th version, respectively. The area under the receiver (AUC) of 4th and 5th versions of BI-RADS was 0.76 and 0.74 (both P values < 0.001, 95 confidence intervals = 0.66-0.87 and 0.63-0.85 respectively). P value for comparison was insignificant. Conclusion: The risk of malignancy increased with the heterogeneity of microcalcifications, especially in the groups with heterogeneity in density, however with no statistically significant difference. BI-RADS 5th edition could predict the likelihood of malignancy as well as 4th version. © 2018, Iranian Journal of Radiology

Effects of variations of flow and heart rate on intra-aneurysmal hemodynamics in a ruptured internal carotid artery aneurysm during exercise

Background: Hemodynamics is thought to play an important role in the mechanisms responsible for initiation, growth, and rupture of intracranial aneurysms. Computational fluid dynamic (CFD) analysis is used to assess intra-aneurysmal hemodynamics. Objectives: This study aimed to investigate the effects of variations in heart rate and internal carotid artery (ICA) flow rate on intra-aneurysmal hemodynamics, in an ICA aneurysm, by using computational fluid dynamics. Patients and Methods: Computed tomography angiography (CTA) was performed in a 55 years old female case, with a saccular ICA aneurysm, to create a patient-specific geometrical anatomic model of the aneurysm. The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling. Results: Results showed significant changes for the three simulated states. For a proportion of the states examined, results were counterintuitive. Systolic and time-averaged wall shear stress and pressure on the aneurysm wall showed a proportional evolution with the mainstream flow rate. Conclusion: Results reinforced the pivotal role of vascular geometry, with respect to hemodynamics, together with the importance of performing patient-specific CFD analyses, through which the effect of different blood flow conditions on the aneurysm hemodynamics could be evaluated

Comparing ovarian radiation doses in flat-panel and conventional angiography during uterine artery embolization: A randomized clinical trial

Background: Uterine artery embolization (UAE) is a minimally invasive procedure performed under fluoroscopy for the treatment of uterine fibroids and accompanied by radiation exposure. Objectives: To compare ovarian radiation doses during uterine artery embolization (UAE) in patients using conventional digital subtraction angiography (DSA) with those using digital flat-panel technology. Patients and Methods: Thirty women who were candidates for UAE were randomly enrolled for one of the two angiographic systems. Ovarian doses were calculated according to in-vitro phantom study results using entrance and exit doses and were compared between the two groups. Results: The mean right entrance dose was 1586±1221 mGy in the conventional and 522.3±400.1 mGy in the flat panel group (P=0.005). These figures were 1470±1170 mGy and 456±396 mGy, respectively for the left side (P=0.006). The mean right exit dose was 18.8±12.3 for the conventional and 9.4±6.4 mGy for the flat panel group (P=0.013). These figures were 16.7±11.3 and 10.2±7.2 mGy, respectively for the left side (P=0.06). The mean right ovarian dose was 139.9±92 in the conventional and 23.6±16.2 mGy in the flat panel group (P<0.0001). These figures were 101.7±77.6 and 24.6±16.9 mGy, respectively for the left side (P=0.002). Conclusion: Flat panel system can significantly reduce the ovarian radiation dose during UAE compared with conventional DSA. © 2013, Tehran University of Medical Sciences and Iranian Society of Radiology; Licensee KowsarKowsar Ltd

Country development and manuscript selection bias: a review of published studies

BACKGROUND: Manuscript selection bias is the selective publication of manuscripts based on study characteristics other than quality indicators. One reason may be a perceived editorial bias against the researches from less-developed world. We aimed to compare the methodological quality and statistical appeal of trials from countries with different development status and to determine their association with the journal impact factors and language of publication. METHODS: Selection criteria: Based on the World Bank income criteria countries were divided into four groups. All records of clinical trials conducted in each income group during 1993 and 2003 were included if they contained abstract and study sample size. Data sources: Cochrane Controlled Trials Register was searched and 50 articles selected from each income group using a systematic random sampling method in years 1993 and 2003 separately. Data extraction: Data were extracted by two reviewers on the language of publication, use of randomization, blinding, intention to treat analysis, study sample size and statistical significance. Disagreement was dealt with by consensus. Journal impact factors were obtained from the institute for scientific information. RESULTS: Four hundred records were explored. Country income had an inverse linear association with the presence of randomization (chi2 for trend = 5.6, p = 0.02) and a direct association with the use of blinding (chi2 for trend = 6.9, p = 0.008); although in low income countries the probability of blinding was increased from 36% in 1993 to 46% in 2003. In 1993 the results of 68% of high income trials and 64.7% of other groups were statistically significant; but in 2003 they were 66% and 82% respectively. Study sample size and income were the only significant predictors of journal impact factor. CONCLUSION: The impact of country development on manuscript selection bias is considerable and may be increasing over time. It seems that one reason may be more stringent implementation of the guidelines for improving the reporting quality of trials on developing world researchers. Another reason may be the presumptions of the researchers from developing world about the editorial bias against their nationality

Velocity measurement in carotid artery: Quantitative comparison of time-resolved 3D phase-contrast MRI and image-based computational fluid dynamics

Background: Understanding hemodynamic environment in vessels is important for realizing the mechanisms leading to vascular pathologies. Objectives: Three-dimensional velocity vector field in carotid bifurcation is visualized using TR 3D phase-contrast magnetic resonance imaging (TR 3D PC MRI) and computational fluid dynamics (CFD). This study aimed to present a qualitative and quantitative comparison of the velocity vector field obtained by each technique. Subjects and Methods: MR imaging was performed on a 30-year old male normal subject. TR 3D PC MRI was performed on a 3 T scanner to measure velocity in carotid bifurcation. 3D anatomical model for CFD was created using images obtained from time-of-flight MR angiography. Velocity vector field in carotid bifurcation was predicted using CFD and PC MRI techniques. A statistical analysis was performed to assess the agreement between the two methods. Results: Although the main flow patterns were the same for the both techniques, CFD showed a greater resolution in mapping the secondary and circulating flows. Overall root mean square (RMS) errors for all the corresponding data points in PC MRI and CFD were 14.27% in peak systole and 12.91% in end diastole relative to maximum velocity measured at each cardiac phase. Bland-Altman plots showed a very good agreement between the two techniques. However, this study was not aimed to validate any of methods, instead, the consistency was assessed to accentuate the similarities and differences between Time-resolved PC MRI and CFD. Conclusion: Both techniques provided quantitatively consistent results of in vivo velocity vector fields in right internal carotid artery (RCA). PC MRI represented a good estimation of main flow patterns inside the vasculature, which seems to be acceptable for clinical use. However, limitations of each technique should be considered while interpreting results

Efficacy of transarterial chemoembolization on lesion reduction in colorectal liver metastases

Following failure of systemic chemotherapy, transarterial chemoembolization (TACE) is an available method to control unresectable liver metastases from colorectal carcinoma (CRC). The aim of present study was to evaluate the efficacy of chemoembolization for inoperable metastatic liver lesions from CRC. Forty-five CRC patients with liver metastases resistant to systemic chemotherapy were enrolled in our study. For each patient, three session of TACE were conducted with 45 days interval. A combination of mitomycin, doxorubicin, and lipiodol were used for TACE. A tri-phasic computed tomography scan and biochemical laboratory tests were performed for all patients at baseline and 30 days after each TACE. Image analysis included measurement of lesion diameters as well as contrast enhancement. Eleven patients deceased before completing three session and the final analyses were performed on the remaining 34 patients. Evaluation of a total 93 lesions in all patients after chemoembolization sessions revealed a 25.88 reduction in anteroposterior (AP) diameter, 33.92 transverse (T) diameter, and 42.22 in product of APxT diameter of lesions (P<0.001 for all instances). CT scan showed a total disappearance of 33 of lesions and evident reduction in contrast enhancement in 16 of them. There were no changes in contrast enhancement in 51 of lesions. Evaluation of single largest lesion in each patient revealed 57.32 reduction in AP diameter, 59.66 in T diameter, and 62.17 in product of APxT diameters (P<0.001 for all diameters). TACE offers a viable option for CRC patients with unresectable liver metastases by significantly reducing lesion size and contrast enhancement. © 2012 Tehran University of Medical Sciences. All rights reserved

Synthetic genetic circuits to uncover the OCT4 trajectories of successful reprogramming of human fibroblasts

Reprogramming human fibroblasts to induced pluripotent stem cells (iPSCs) is inefficient, with heterogeneity among transcription factor (TF) trajectories driving divergent cell states. Nevertheless, the impact of TF dynamics on reprogramming efficiency remains uncharted. We develop a system that accurately reports OCT4 protein levels in live cells and use it to reveal the trajectories of OCT4 in successful reprogramming. Our system comprises a synthetic genetic circuit that leverages noise to generate a wide range of OCT4 trajectories and a microRNA targeting endogenous OCT4 to set total cellular OCT4 protein levels. By fusing OCT4 to a fluorescent protein, we are able to track OCT4 trajectories with clonal resolution via live-cell imaging. We discover that a supraphysiological, stable OCT4 level is required, but not sufficient, for efficient iPSC colony formation. Our synthetic genetic circuit design and high-throughput live-imaging pipeline are generalizable for investigating TF dynamics for other cell fate programming applications

Global, regional, and national mortality among young people aged 10–24 years, 1950–2019: a systematic analysis for the Global Burden of Disease Study 2019

Summary: Background Documentation of patterns and long-term trends in mortality in young people, which reflect huge changes in demographic and social determinants of adolescent health, enables identification of global investment priorities for this age group. We aimed to analyse data on the number of deaths, years of life lost, and mortality rates by sex and age group in people aged 10–24 years in 204 countries and territories from 1950 to 2019 by use of estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. Methods We report trends in estimated total numbers of deaths and mortality rate per 100 000 population in young people aged 10–24 years by age group (10–14 years, 15–19 years, and 20–24 years) and sex in 204 countries and territories between 1950 and 2019 for all causes, and between 1980 and 2019 by cause of death. We analyse variation in outcomes by region, age group, and sex, and compare annual rate of change in mortality in young people aged 10–24 years with that in children aged 0–9 years from 1990 to 2019. We then analyse the association between mortality in people aged 10–24 years and socioeconomic development using the GBD Socio-demographic Index (SDI), a composite measure based on average national educational attainment in people older than 15 years, total fertility rate in people younger than 25 years, and income per capita. We assess the association between SDI and all-cause mortality in 2019, and analyse the ratio of observed to expected mortality by SDI using the most recent available data release (2017). Findings In 2019 there were 1·49 million deaths (95% uncertainty interval 1·39–1·59) worldwide in people aged 10–24 years, of which 61% occurred in males. 32·7% of all adolescent deaths were due to transport injuries, unintentional injuries, or interpersonal violence and conflict; 32·1% were due to communicable, nutritional, or maternal causes; 27·0% were due to non-communicable diseases; and 8·2% were due to self-harm. Since 1950, deaths in this age group decreased by 30·0% in females and 15·3% in males, and sex-based differences in mortality rate have widened in most regions of the world. Geographical variation has also increased, particularly in people aged 10–14 years. Since 1980, communicable and maternal causes of death have decreased sharply as a proportion of total deaths in most GBD super-regions, but remain some of the most common causes in sub-Saharan Africa and south Asia, where more than half of all adolescent deaths occur. Annual percentage decrease in all-cause mortality rate since 1990 in adolescents aged 15–19 years was 1·3% in males and 1·6% in females, almost half that of males aged 1–4 years (2·4%), and around a third less than in females aged 1–4 years (2·5%). The proportion of global deaths in people aged 0–24 years that occurred in people aged 10–24 years more than doubled between 1950 and 2019, from 9·5% to 21·6%. Interpretation Variation in adolescent mortality between countries and by sex is widening, driven by poor progress in reducing deaths in males and older adolescents. Improving global adolescent mortality will require action to address the specific vulnerabilities of this age group, which are being overlooked. Furthermore, indirect effects of the COVID-19 pandemic are likely to jeopardise efforts to improve health outcomes including mortality in young people aged 10–24 years. There is an urgent need to respond to the changing global burden of adolescent mortality, address inequities where they occur, and improve the availability and quality of primary mortality data in this age group