199 research outputs found
Ascites due to right atrial myxoma in a haemodialysis patient
BACKGROUND: Persistent fluid overload in patients on renal replacement therapy despite good dialysis adequacy or obvious cardiac dysfunction should prompt a search for rarer causes. CASE PRESENTATION: We report here a rare cause of persistent peripheral oedema and ascites in a well-dialysed patient. CT scanning revealed a right atrial myxoma that was later confirmed on an echocardiogram. CONCLUSION: Fluid overload states are common in patients on dialysis. Common causes are inadequacy of dialysis and non-compliance. Where aetiology is not easily apparent further investigations into rarer causes should be sought
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Development of ambient-cured geopolymer mortars with construction and demolition waste-based materials
YesDegrading infrastructure and applications of structural demolition create
tremendous amounts of construction and demolition waste (CDW) all around
the world. To address this issue in an effective way, recycling CDW in a most appropriate
way has become a global concern in recent years. To this end, this study
focused on the valorization of CDW-based materials such as tile, bricks, glass,
and concrete in the development of geopolymer mortars. CDWs were first collected
from demolition zone and then subjected to crushing-milling operations. To
investigate the influence of slag (S) addition to the mixtures, 20% S substituted
mixture designs were also made. Fine recycled concrete aggregates (FRCA) obtained
from crushing and sieving of the waste concrete were used as the aggregate.
A series of mixtures were designed using different proportions of three distinct
alkali activators such as sodium hydroxide (NaOH), sodium silicate (Na2SiO3),
and calcium hydroxide (CH; Ca(OH)2). To improve their applicability, the mixtures
were left to cure at room temperature rather than the heat curing which
is frequently applied in the literature. After 28 days ambient curing, the 100%
CDW-based geopolymer mortar activated with three different activators reached
a compressive strength of 31.6 MPa, whereas the 20% S substituted geopolymer
mortar showed a 51.9 MPa compressive strength. While the geopolymer mortars
activated with only NaOH exhibited poor performance, it was found that the
use of Na2SiO3 and CH improved the mechanical performance. Main geopolymerization
products were related to NASH (Sodium alumino-silicate hydrate),
CASH (Calcium alumino-silicate hydrate), and C(N)ASH gel formations. Results
demonstrated that mixed CDWs can be employed in the manufacturing
geopolymers, making them potential alternatives to Portland cement (PC)-based
systems by being eco-friendly, energy-efficient, and comparable in compressive
strength.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100
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Development of ambient-cured geopolymer mortars with construction and demolition waste-based materials
YesDegrading infrastructure and applications of structural demolition create tremendous amounts of construction and demolition waste (CDW) all around the world. To address this issue in an effective way, recycling CDW in a most appropriate way has become a global concern in recent years. To this end, this study focused on the utilization of CDW-based materials such as hollow brick (HB), red clay brick (RCB), roof tile (RT), glass (G) and concrete (C) in the production of geopolymer mortars. These materials were first collected from an urban transformation area and then subjected to an identical two-step crushing-milling procedure to provide sufficient fineness for geopolymerization. To investigate the influence of blast furnace slag (S) addition to the CDW-based mixtures, 20% S substituted mixture designs were also made. Fine recycled concrete aggregates (FRCA) obtained from crushing and sieving of the waste concrete were used as the aggregate. A series of mixtures were designed using different proportions of three distinct alkali activators such as sodium hydroxide (NaOH), sodium silicate (Na2SiO3) and calcium hydroxide (Ca[OH]2). To improve their applicability, the mixtures were left to cure at room temperature rather than the heat curing which is frequently applied in the literature. After 28 days of ambient curing, the 100% CDW-based geopolymer mortar activated with three different activators reached a compressive strength of 31.6 MPa, whereas the 20% S substituted geopolymer mortar achieved a compressive strength of 51.9 MPa. While the geopolymer mortars activated with only NaOH exhibited poor performance, it was found that the use of Na2SiO3 and Ca(OH)2 improved the compressive strength. Main geopolymerization products were related to NASH, CASH, and C(N)ASH gel formations. Our results demonstrated that mixed CDW-based materials can be employed in the manufacturing geopolymers, making them potential alternatives to Portland cement-based systems by being eco-friendly, energy-efficient, and comparable in compressive strength.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100
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Characterization and life cycle assessment of geopolymer mortars with masonry units and recycled concrete aggregates assorted from construction and demolition waste
YesDeveloping a fast, cost-effective, eco-friendly solution to recycle large amounts of construction and demolition waste (CDW) generated from construction industry-related activities and natural disasters is crucial. The present investigation aims to offer a solution for repurposing CDW into building materials suitable for accelerated construction and housing in developing countries and disaster-prone areas. Feasibility of recycled concrete aggregate (RCA) inclusion in geopolymer mortars constituted entirely from CDW (masonry elements) was investigated via an environmental impact-oriented approach by addressing the composition related key parameters. Mechanical performance was evaluated through compressive strength tests, and scanning electron microscope (SEM) imaging with line mapping analyses were carried out to monitor the interfacial transition zone (ITZ) properties. To investigate the environmental impacts of the geopolymer mortars and highlight the advantages over Portland cement-based mortars, a cradle-to-gate life cycle assessment (LCA) was performed. Findings revealed that roof tile (RT)-based geopolymer mortars mainly exhibited better strength performance due to their finer particle size. Mixtures activated with 15 M NaOH solution and cured at 105 °C achieved an average compressive strength above 55 MPa. RCA size was the most influential parameter on compressive strength, and a smaller maximum RCA size significantly increased the compressive strength. Microstructural analyses showed that the ITZ around smaller RCAs was relatively thinner, resulting in better compressive strength results. LCA proved that CDW-based geopolymer mortars provide the same compressive strength with around 60% less CO2 emissions and similar energy consumption compared to Portland cement-based mortars.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100. The authors also wish to acknowledge the support of the Scientific and Technical Research Council of Turkey (TUBITAK) provided under project: 117M44
Integrating Lean Six Sigma and discrete-event simulation for shortening the appointment lead-time in gynecobstetrics departments: a case study
Long waiting time to appointment may be a worry for pregnant women, particularly those who need perinatology consultation since it could increase anxiety and, in a worst case scenario, lead to an increase in fetal, infant, and maternal mortality. Treatment costs may also increase since pregnant women with diverse pathologies can develop more severe complications. As a step towards improving this process, we propose a methodological approach to reduce the appointment lead-time in outpatient gynecobstetrics departments. This framework involves combining the Six Sigma method to identify defects in the appointment scheduling process with a discrete-event simulation (DES) to evaluate the potential success of removing such defects in simulation before we resort to changing the real-world healthcare system. To do these, we initially characterize the gynecobstetrics department using a SIPOC diagram. Then, six sigma performance metrics are calculated to evaluate how well the department meets the government target in relation to the appointment lead-time. Afterwards, a cause-and-effect analysis is undertaken to identify potential causes of appointment lead-time variation. These causes are later validated through ANOVA, regression analysis, and DES. Improvement scenarios are next designed and pretested through computer simulation models. Finally, control plans are deployed to maintain the results achieved through the implementation of the DES-Six sigma approach. The aforementioned framework was validated in a public gynecobstetrics outpatient department. The results revealed that mean waiting time decreased from 6.9 days to 4.1 days while variance passed from 2.46 days2 to 1.53 days2
Protective efficiacy of taurine against pulmonary edema progression: experimental study
Re-expansion pulmonary edema (RPE) is an acute, rare and potentially lethal complication [1,2]. Its beginning is sudden and dramatic. The mechanism is not yet fully understood [1]. Some authors suggest that it may occur after rapid re-inflation of a collapsed lung [1]. It was reported by other authors that it may relate to surfactant depletion or may result from hypoxic capillary damage, leading to increased capillary permeability [1,3]. In RPE, unilateral lung injury is initiated by cytotoxic oxygen metabolites and temporally associated with an influx of polymorphonuclear neutrophils [1]. These toxic oxygen products are the results of re-oxygenation of a collapsed lung. Treatment of re-expansion pulmonary edema is basically preventive [4]
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