153 research outputs found
Assessment amount of the horizontal and vertical displacements of sea wall using FLAC3D software
Sea Walls are constructed to protect coastal against of waves and prevent water to coastal. In order to properly understand the behavior of these structures must have proper information of loads to the structure. One of the main significance loads over the sea wall is wave’s loads. Weight forces the walls, Weight backfill, Seawater weight on the heel wall and Forces exerted on the beach other forces that enters the coastal wall. Considering the importance of seawalls study on the stability of these structures has been the subject of study. In order to achieve the objectives of the study, three scenarios include changes in the geometry of the wall and Soil properties. In present study four geometry vertical, inclined, convex, concave, are considered and modeling with Flac 3D software. The results of this study showed that the minimum of horizontal and vertical displacement are about convex seawalls and the maximum of them is about vertical concave seawalls. Also the results showed that in the higher shear strength of soils the minimum of horizontal and vertical displacements occurred
Memristive behavior in a junctionless flash memory cell
We report charge storage based memristive operation of a junctionless thin film flash memory cell when it is operated as a two terminal device by grounding the gate. Unlike memristors based on nanoionics, the presented device mode, which we refer to as the flashristor mode, potentially allows greater control over the memristive properties, allowing rational design. The mode is demonstrated using a depletion type n-channel ZnO transistor grown by atomic layer deposition (ALD), with HfO2 as the tunnel dielectric, Al2O3 as the control dielectric, and non-stoichiometric silicon nitride as the charge storage layer. The device exhibits the pinched hysteresis of a memristor and in the unoptimized device, Roff/Ron ratios of about 3 are presented with low operating voltages below 5 V. A simplified model predicts Roff/Ron ratios can be improved significantly by adjusting the native threshold voltage of the devices. The repeatability of the resistive switching is excellent and devices exhibit 106s retention time, which can, in principle, be improved by engineering the gate stack and storage layer properties. The flashristor mode can find use in analog information processing applications, such as neuromorphic computing, where well-behaving and highly repeatable memristive properties are desirable. © 2015 AIP Publishing LLC
Effect of indium doping on the electrical and structural properties of TiO2 thin films used in MOS devices
We investigated the effect of Indium (In) doping on the structural and electrical properties of Ti/Au/ TiO2:In/n-Si metal-oxide-semiconductor (MOS) devices. Sputtering grown TiO2 thin films on Si substrate were doped using two In-films with 15 nm and 50 nm thicknesses leading to two structures named Low Indium Doped (LID) sample and High Indium Doped (HID) sample, respectively. XRD analysis shows no diffraction pattern related to Indium indicating that In has been incorporated into the TiO2 lattice. Current-Voltage (I-V) characteristics show that rectification ratio at 2V is higher for HID sample than for LID sample. Evaluated barrier height, ϕB0 , decreased while the ideality factor, n, increased with decreasing temperature. Such behavior is ascribed to barrier inhomogeneity that was assumed to have a Gaussian Distribution (GD) of barrier heights at interface. Evidence of such GD was confirmed by plotting ϕB0versus n. High value of mean barrier ϕ̅B0 and lower value of standard deviation (σ) of HID structure are due to indium doping which increases the barrier homogeneities. Finally, estimated Richardson constants A* are in good agreement with theoretic values (112 A/cm2K2), particularly, for the HID structure
Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies
Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p<0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p<0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding
EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial
More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369
An inter-laboratory effort to harmonize the cell-delivered in vitro dose of aerosolized materials
Air-liquid interface (ALI) lung cell models cultured on permeable transwell inserts are increasingly used for respiratory hazard assessment requiring controlled aerosolization and deposition of any material on ALI cells. The approach presented herein aimed to assess the transwell insert-delivered dose of aerosolized materials using the VITROCELL® Cloud12 system, a commercially available aerosol-cell exposure system. An inter-laboratory comparison study was conducted with seven European partners having different levels of experience with the VITROCELL® Cloud12. A standard operating procedure (SOP) was developed and applied by all partners for aerosolized delivery of materials, i.e., a water-soluble molecular substance (fluorescence-spiked salt) and two poorly soluble particles, crystalline silica quartz (DQ 12) and titanium dioxide nanoparticles (TiO 2 NM-105). The material dose delivered to transwell inserts was quantified with spectrofluorometry (fluorescein) and with the quartz crystal microbalance (QCM) integrated in the VITROCELL® Cloud12 system. The shape and agglomeration state of the deposited particles were confirmed with transmission electron microscopy (TEM). Inter-laboratory comparison of the device-specific performance was conducted in two steps, first for molecular substances (fluorescein-spiked salt), and then for particles. Device- and/or handling-specific differences in aerosol deposition of VITROCELL® Cloud12 systems were characterized in terms of the so-called deposition factor (DF), which allows for prediction of the transwell insert-deposited particle dose from the particle concentration in the aerosolized suspension. Albeit DF varied between the different labs from 0.39 to 0.87 (mean (coefficient of variation (CV)): 0.64 (28%)), the QCM of each VITROCELL® Cloud 12 system accurately measured the respective transwell insert-deposited dose. Aerosolized delivery of DQ 12 and TiO 2 NM-105 particles showed good linearity (R 2 > 0.95) between particle concentration of the aerosolized suspension and QCM-determined insert-delivered particle dose. The VITROCELL® Cloud 12 performance for DQ 12 particles was identical to that for fluorescein-spiked salt, i.e., the ratio of measured and salt-predicted dose was 1.0 (29%). On the other hand, a ca. 2-fold reduced dose was observed for TiO 2 NM-105 (0.54 (41%)), which was likely due to partial retention of TiO 2 NM-105 agglomerates in the vibrating mesh nebulizer of the VITROCELL® Cloud12. This inter-laboratory comparison demonstrates that the QCM integrated in the VITROCELL® Cloud 12 is a reliable tool for dosimetry, which accounts for potential variations of the transwell insert-delivered dose due to device-, handling- and/or material-specific effects. With the detailed protocol presented herein, all seven partner laboratories were able to demonstrate dose-controlled aerosolization of material suspensions using the VITROCELL® Cloud12 exposure system at dose levels relevant for observing in vitro hazard responses. This is an important step towards regulatory approved implementation of ALI lung cell cultures for in vitro hazard assessment of aerosolized materials
Epidemiology of surgery associated acute kidney injury (EPIS-AKI): a prospective international observational multi-center clinical study
Purpose: The incidence, patient features, risk factors and outcomes of surgery-associated postoperative acute kidney injury (PO-AKI) across different countries and health care systems is unclear. Methods: We conducted an international prospective, observational, multi-center study in 30 countries in patients undergoing major surgery (> 2-h duration and postoperative intensive care unit (ICU) or high dependency unit admission). The primary endpoint was the occurrence of PO-AKI within 72 h of surgery defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints included PO-AKI severity and duration, use of renal replacement therapy (RRT), mortality, and ICU and hospital length of stay. Results: We studied 10,568 patients and 1945 (18.4%) developed PO-AKI (1236 (63.5%) KDIGO stage 1500 (25.7%) KDIGO stage 2209 (10.7%) KDIGO stage 3). In 33.8% PO-AKI was persistent, and 170/1945 (8.7%) of patients with PO-AKI received RRT in the ICU. Patients with PO-AKI had greater ICU (6.3% vs. 0.7%) and hospital (8.6% vs. 1.4%) mortality, and longer ICU (median 2 (Q1-Q3, 1-3) days vs. 3 (Q1-Q3, 1-6) days) and hospital length of stay (median 14 (Q1-Q3, 9-24) days vs. 10 (Q1-Q3, 7-17) days). Risk factors for PO-AKI included older age, comorbidities (hypertension, diabetes, chronic kidney disease), type, duration and urgency of surgery as well as intraoperative vasopressors, and aminoglycosides administration. Conclusion: In a comprehensive multinational study, approximately one in five patients develop PO-AKI after major surgery. Increasing severity of PO-AKI is associated with a progressive increase in adverse outcomes. Our findings indicate that PO-AKI represents a significant burden for health care worldwide
Qualitative Evaluation of Central Library's Web Sites of Medical Universities in Iran with WEBQEM
Introduction: The homepage is the initial place at which the users are directed towards having access to the available resources. This makes web designing of high importance to university administrators and authorities. The purpose of this study was to conduct a qualitative evaluation of websites with WEBQEM in libraries of Medical Universities in the Islamic Republic of Iran. Methods: This study was a descriptive survey which was conducted on 24 websites. Data were gathered on the basis of WEBQEM checklists. Data analysis was performed by using SPSS software version 13. The evaluation was carried out by applying four criteria of WEBQEM. Results: The websites' reliability was evaluated as "Very Good", with the average score of 0.82, and its efficiency as "Good" with the average score of 0.64. Usability and functionality scored an average of 0.5 and 0.52, respectively. Finally, half of the websites, on which this study was conducted, were evaluated as "Good "while the other half were as "Average". Discussion: Considering the average scores obtained by using the four main criteria of the study, it was conceived that the in terms of functionality and usability of these web sites had some shortcomings. Although reliability and efficiency scored average, some of the websites were not of the expected quality by the main criteria. Keyword
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