68 research outputs found
Determination of Arsenic, Mercury and Barium in herbarium mount paper using dynamic ultrasound-assisted extraction prior to atomic fluorescence and absorption spectrometry
A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimised by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min-1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01ng g-1 and 1.25 ng g-1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g-1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 µg g-1 for Ba, 0.035–10.47 µg g-1 for As and 0.0046–2.37 µg g-1 for Hg
Outflow obstruction after living donor liver transplantation managed with a temporary vena cava filter:A case report
Introduction: Outflow obstruction is a rare but critical vascular complication in liver transplantation, which may lead to graft loss and mortality. We report a case of caval vein outflow obstruction due to retrohepatic compression after living donor liver transplantation (LDLT), which was managed by temporary implantation of a vena cava filter. Presentation of case: A 63-year-old male with end stage liver disease presented with caval vein outflow obstruction and massive ascites 12 days after right lobe LDLT. We opted for a minimally invasive approach and implanted a vena cava filter at the compressed site through transjugular route. The patient's ascites drainage significantly decreased and graft function maintained stable after the intervention. On day 50 posttransplant, the filter was successfully removed and the patient was discharged without complications. Discussion: Outflow obstruction after liver transplantation can result from anastomotic stenosis, graft size mismatch, thrombosis or compression of the outflow tract. Various management strategies have been employed both peri- and posttransplant, ranging from surgical interventions to minimally-invasive techniques. The treatment strategy should be tailored to the individual case, considering the timing of presentation and the specific cause for the obstruction. Conclusion: We successfully managed a case of compressive outflow obstruction by temporary implantation of a vena cava filter after LDLT. The vena cava filter was safely removed under angiography.</p
Successful adult domino living donor liver transplantation in methylmalonic acidemia:case report
Background: Liver transplantation (LT) is a therapeutic option in multiple inherited metabolic diseases (IMDs), including methylmalonic acidemia (MMA), as LT reduces the risk of acute metabolic decompensations and long-term complications associated with these diseases. In certain IMDs, such as maple syrup urine disease (MSUD), domino liver transplant (DLT) is an accepted and safe method which expands the donor pool. However, only one adult case of DLT using an MMA donor liver has been reported; outcome and safety are still unknown and questioned. Case Description: In this case report, we describe our experience with DLT using MMA livers. Two adult MMA patients underwent living donor liver transplant (LDLT); their MMA livers were consecutively transplanted into two patients on the liver transplant waiting list who had limited chance of receiving a liver transplant in the short term due to their low model for end-stage liver disease (MELD) scores. No severe peri- or postoperative complications occurred, however the recipients of the MMA livers biochemically now have mild MMA. Conclusions: DLT using MMA grafts is a feasible strategy to treat end-stage liver disease and expand the donor organ pool. However, the recipient of the MMA domino liver may develop mild MMA which could affect quality of life, and long-term safety remains unclear. Further long-term of outcomes for domino recipients of MMA livers, focusing on quality of life and any metabolic complications of transplantation are needed to better define the risks and benefits
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Temperature gradient-induced magnetization reversal of single ferromagnetic nanowires
In this study, we investigate the temperature- and temperature gradient-dependent magnetization reversal process of individual, single-domain Co39Ni61 and Fe15Ni85 ferromagnetic nanowires via the magneto-optical Kerr effect and magnetoresistance measurements. While the coercive fields (HC) and therefore the magnetic switching fields (HSW) generally decrease under isothermal conditions at elevated base temperatures (Tbase), temperature gradients (ΔT) along the nanowires lead to an increased switching field of up to 15% for ΔT  = 300 K in Co39Ni61 nanowires. This enhancement is attributed to a stress-induced, magneto-elastic anisotropy term due to an applied temperature gradient along the nanowire that counteracts the thermally assisted magnetization reversal process. Our results demonstrate that a careful distinction between locally elevated temperatures and temperature gradients has to be made in future heat-assisted magnetic recording devices
Successful adult domino living donor liver transplantation in methylmalonic acidemia:case report
Background: Liver transplantation (LT) is a therapeutic option in multiple inherited metabolic diseases (IMDs), including methylmalonic acidemia (MMA), as LT reduces the risk of acute metabolic decompensations and long-term complications associated with these diseases. In certain IMDs, such as maple syrup urine disease (MSUD), domino liver transplant (DLT) is an accepted and safe method which expands the donor pool. However, only one adult case of DLT using an MMA donor liver has been reported; outcome and safety are still unknown and questioned. Case Description: In this case report, we describe our experience with DLT using MMA livers. Two adult MMA patients underwent living donor liver transplant (LDLT); their MMA livers were consecutively transplanted into two patients on the liver transplant waiting list who had limited chance of receiving a liver transplant in the short term due to their low model for end-stage liver disease (MELD) scores. No severe peri- or postoperative complications occurred, however the recipients of the MMA livers biochemically now have mild MMA. Conclusions: DLT using MMA grafts is a feasible strategy to treat end-stage liver disease and expand the donor organ pool. However, the recipient of the MMA domino liver may develop mild MMA which could affect quality of life, and long-term safety remains unclear. Further long-term of outcomes for domino recipients of MMA livers, focusing on quality of life and any metabolic complications of transplantation are needed to better define the risks and benefits
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Monitoring the FLASH Cryomodule Transportation from DESY Hamburg to CEA Saclay: Coupler Contact, Vacuum, Acceleration and Vibration Analysis
With a view to the series production of one hundred, 12 m long XFEL 1.3 GHz cryomodules and their transportation from the assembly site at CEA Saclay (F) to the installation site at DESY Hamburg (D) a test transportation of a FLASH cryomodule has been performed, in the condition foreseen for the mass transportation. The present study examines the stresses induced on the module and verifies the damping capabilities of the transport frame in order to minimize risk of damage to the most critical components. During the transportation, acceleration and vibration have been monitored as well as coupler antenna contacts and vacuum performances. This paper describes the analysis performed and compares those results to the data of a similar transportation study at Fermilab for the CM1 cryomodule
Design ecologies exercise: the Innovation Landscape Matrix
This chapter on sustainable design pedagogy shares the Innovation Landscape Matrix (ILM) as a tool for understanding design ecologies and making visible the systemic interactions that connect across multiple scales. Students use contextualizing questions in their design process before engaging with the Innovation Landscape Matrix. The ILM maps product, service, and system against materials, people, and structures. Each box of the matrix poses different questions to consider, helping students to see current dominant areas of design focus – often in the area of products and materials. This work helps reveal gaps in the landscape when thinking about relationships between products, services, and systems and the contexts in which they operate. This exercise positions an ecosystem perspective as central to design learning
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