50 research outputs found
Sensor and Actuator Fault-Hiding Reconfigurable Control Design for a Four-Tank System Benchmark
Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey
Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
Metal pollution assessment in the surface sediment of Lake Nasser, Egypt
Eight heavy metals were measured seasonally in the sediment of Lake Nasser during 2013. 27 sites were chosen through 9 sectors across the main channel of the lake from Abu-Simbel to Aswan High Dam to assess the levels of the selected metals. The abundance of these metals was in the order of Fe > Mn > Zn > Cr > Ni > Cu > Pb > Cd, with mean concentrations of 12.41 mg/g, 279.56, 35.38, 30.79, 27.56, 21.78, 11.21 and 0.183 μg/g, respectively. Heavy metals are positively correlated with fine particles (mud fractions) and organic matter accumulation. The results showed perspicuous spatial high significant differences (P < 0.01) for all the measured metals. Fe, Cr, Ni, Pb and Cd exhibited temporally high significant differences (P < 0.01) before and after the flood period. Four Pollution Indices were used for the environmental assessment of Lake Nasser sediment. The indices included three single indices, Enrichment Factor (EF), Index of Geo-accumulation (Igeo) and Contamination Factor (CF). While the fourth, Pollution Load Index (PLI) was an integrated index. The pollution indexes confirmed that the Lake Nasser sediment was not contaminated with these elements. Sediments of Lake Nasser may be represented as a reference for the pre-industrial background of River Nile Sediments downstream Aswan High Dam
Electrochemical Behavior of Inductively Sintered Al/TiO2 Nanocomposites Reinforced by Electrospun Ceramic Nanofibers
This study is focuses on the investigation of the effect of using TiO2 short nanofibers as a reinforcement of an Al matrix on the corrosion characteristics of the produced nanocomposites. The TiO2 ceramic nanofibers used were synthesized via electrospinning by sol-gel process, then calcinated at a high temperature to evaporate the residual polymers. The fabricated nanocomposites contain 0, 1, 3 and 5 wt.% of synthesized ceramic nanofibers (TiO2). Powder mixtures were mixed for 1 h via high-energy ball milling in a vacuum atmosphere before being inductively sintered through a high-frequency induction furnace at 560 °C for 6 min. The microstructure of the fabricated samples was studied by optical microscope and field emission scanning electron microscope (FESEM) before and after corrosion studies. Corrosion behavior of the sintered samples was evaluated by both electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques (PPT) in 3.5% NaCl solution for one hour and 24-h immersion times. The results show that even though the percentage of ceramic nanofibers added negatively control corrosion resistance, it is still possible to increase resistance against corrosion for the fabricated nanocomposite by more than 75% in the longer exposure time periods
The Potential Protective Effect and Underlying Mechanisms of Physiological Unconjugated Hyperbilirubinemia Mediated by UGT1A1 Antisense Oligonucleotide Therapy in a Mouse Model of Cyclosporine A-Induced Chronic Kidney Disease
Cyclosporine A (CSA) is an immunosuppressive drug that has improved transplant survival rates. However, its use is often limited because it is thought to be linked to the development of chronic kidney disease after kidney transplants. This study aimed to investigate the protective effects and underlying mechanisms of physiological unconjugated (UC) hyperbilirubinemia mediated by UGT1A1 antisense oligonucleotide in a mouse model of CsA-induced chronic kidney disease, and match these with that of chitosan (CH) as a natural chelator against kidney injury. In the current study, CsA-treated mice were given an intravenous injection of UGT1A1 antisense morpholino oligonucleotide (16 µg/kg) every third day for 14 days. In serum samples, bilirubin, creatinine, and urea were determined. Markers of oxidative stress, antioxidant activities, and mRNA expression of target genes PPAR-α, cFn, eNOS, NF-B, AT1-R, ETA-R, Kim-1, and NGAL were measured in the kidney tissues. Moreover, histopathological examinations were carried out on the kidney tissue. Physiological UC hyperbilirubinemia could be a promising protective strategy against CsA-induced kidney disease in transplant recipients. UGT1A1 antisense oligonucleotide-induced physiological UC hyperbilirubinemia serum significantly protected against CsA-induced kidney dysfunction. UCB acts as a signaling molecule that protects against kidney disease through different mechanisms, including antioxidant, anti-inflammatory, and hormonal action, by activating nuclear hormone receptors (PPAR-α). Moreover, it significantly downregulated mRNA expression of NF-kB, ETA-R, iNOS, AT1-R, cFn, Kim-1, and NGAL in the kidney tissue and alleviated CsA-induced kidney histological changes in CsA-treated mice
The potential therapeutic effect for melatonin and mesenchymal stem cells on hepatocellular carcinoma
Background/aim: Herein, we investigated the potential therapeutic effect of Melatonin (Mel) and/or mesenchymal stem cells (MSCs) on rat model of HCC.
Materials and Methods: Female mature rats were divided into 5 groups (n = 10/group): normal (Nor), HCC group intraperitoneally injected with 200 mg/kg DEN, and 3 treated groups; HCC + Mel (Mel) group given Mel intraperitoneally 20 mg/kg, twice a week, HCC + MSCs (MSCs) group intravenously injected by 1 × 106 cells, and HCC + MSCs (Mel +MSCs) group.
Results: Rats in HCC group showed most deteriorated effect in form of increased mortality and relative liver weight, elevated serum levels of ALT, AST, ALP, AFP and GGT in addition to increased pre-neoplastic nodules in liver tissues. Liver tissues of HCC group also exhibited lower level of apoptosis as indicated by decreased DNA fragmentation and expression of p53 caspase 9 and caspase 3 genes and increased PCNA immunoreactivity. Moreover, in this group the expression of IL6 and TGFβ1 genes was significantly upregulated. All these deleterious effects induced by DEN were reversed after administration of Mel and/ or MSCs with best improvement for the combined group (MSCs + Mel).
Conclusions: These findings reveal a better therapeutic effect for MSCs when given with Mel and we attribute this beneficial effect, at least in part, to triggering apoptosis and targeting inflammation in HCC. Therefore, combined treatment with Mel and MSCs is recommended to enhance the therapeutic potential against HCC
Evaluation of Mechanical and Tribological Properties of Corn Cob-Reinforced Epoxy-Based Composites—Theoretical and Experimental Study
Epoxy is considered to be the most popular polymer and is widely used in various engineering applications. However, environmental considerations require natural materials-based epoxy. This necessity results in further utilization of natural materials as a natural reinforcement for different types of composites. Corn cob is an example of a natural material that can be considered as an agricultural waste. The objective of the present work is to improve the economic feasibility of corn cob by converting the original corn cob material into powder to be utilized in reinforcing epoxy-based composites. In the experiment, the corn cob was crushed and ground using a grain miller before it was characterized by scanning electron microscopy (SEM). The corn cob powder was added to the epoxy with different weight fractions (2, 4, 6, 8, 10 wt%). In order to prevent corn cob powder agglomeration and ensure homogeneous distribution of the reinforcement inside the epoxy, the ultrasonic technique and a mechanical stirrer were used. Then, the composite’s chemical compositions were evaluated using X-ray diffraction (XRD). The mechanical experiments showed an improvement in the Young’s modulus and compressive yield strength of the epoxy composites, increasing corn cob up to 8 wt% by 21.26% and 22.22%, respectively. Furthermore, tribological tests revealed that reinforcing epoxy with 8 wt% corn cob can decrease the coefficient of friction by 35% and increase wear resistance by 4.8%. A finite element model for the frictional process was constructed to identify different contact stresses and evaluate the load-carrying capacity of the epoxy composites. The finite element model showed agreement with the experimental results. An epoxy containing 8 wt% corn cob demonstrated the optimal mechanical and tribological properties. The rubbed surfaces were investigated by SEM to identify the wear mechanism of different composites
Magnetized Saline Water Irrigation Enhances Soil Chemical and Physical Properties
Due to rapid population growth and pressure on water resources, it is necessary to use economic and non-traditional techniques for irrigation. One of these techniques is the use of salt water after treatment with a magnetic force. A simulation experiment was conducted with soil columns using three quantities of saline water: 0, 3, and 6 g L−1 (S0, S3, and S6). Magnetic forces of 0, 1000, 2000, 3000, 4000, 5000, 6000, and 7000 gauss were used to study the effects of magnetic forces on leachate and soil physicochemical properties at different depths. The results at all soil depths showed that the pH decreased with increasing salinity from S0 to S3 and S6 by an average of 8.44, 8.28, and 8.27%, respectively. Soil EC decreased significantly with depth by 10–35%. The maximum SAR, SSP, and CROSS values (16.3, 51.1, and 17.6, respectively) were reported when no magnetic force was used, while the lowest values (13.9, 49.9, and 15.3) were recorded when using 3000 gauss under S6 within the soil profile. Magnetizing the water halved the EC of the leachate under S0, while it decreased the EC by 12.4% under S3. Increasing the magnetic force enhanced the leachate SAR, SSP, and CROSS values by 4.9–20.4% on average under S3 and S6. Magnetic forces augmented the hydraulic conductivity at the same salinity level and with increasing salinity, resulting in an increment of 50% at S3 and S6 compared with S0. After nine hours, the maximum cumulative infiltration rate was under 1000 and 4000 gauss. Our results demonstrated the important effects of magnetically treated irrigation water and could therefore support its application in agriculture under conditions of low water resources and quality