6 research outputs found
Type D Personality Associated With Increased Risk for Mortality in Adults With Congenital Heart Disease
Background Type D personality has been previously shown to increase the risk for mortality in patients with acquired heart disease.ObjectiveWe aimed to compare mortality in adult patients with congenital heart disease (CHD) with and without type D.Methods Survival was assessed using prospective data from the Dutch national Congenital Corvitia registry for adults with CHD. Patients were randomly selected from the registry and characterized at inclusion in 2009 for the presence of type D using the DS14 questionnaire.Results One thousand fifty-five patients, with 484 (46%) males, a mean (SD) age of 41 (14) years, 613 (58%) having mild CHD, 348 (33%) having moderate CHD, and 94 (9%) having severe CHD, were included. Type D personality was present in 225 patients (21%). Type D was associated with an increased risk for all-cause mortality independent of age, sex, New York Heart Association class, number of prescribed medications, depression, employment status, and marital status (hazard ratio, 1.94; 95% confidence interval, 1.05–3.57; P = .033).Conclusion Type D personality was associated with an increased risk for all-cause mortality in adult patients with CHD
Detection of Cardioembolic Sources With Nongated Cardiac Computed Tomography Angiography in Acute Stroke: Results From the ENCLOSE Study
BACKGROUND: Identifying cardioembolic sources in patients with acute ischemic stroke is important for the choice of secondary prevention strategies. We prospectively investigated the yield of admission (spectral) nongated cardiac computed tomography angiography (CTA) to detect cardioembolic sources in stroke. METHODS: Participants of the ENCLOSE study (Improved Prediction of Recurrent Stroke and Detection of Small Volume Stroke) with transient ischemic attack or acute ischemic stroke with assessable nongated head-to-heart CTA at the University Medical Center Utrecht were included between June 2017 and March 2022. The presence of cardiac thrombus on cardiac CTA was based on a Likert scale and dichotomized into certainly or probably absent versus possibly, probably, or certainly present. The diagnostic certainty of cardiac thrombus was evaluated again on spectral computed tomography reconstructions. The likelihood of a cardioembolic source was determined post hoc by an expert panel in patients with cardiac thrombus on CTA. Parametric and nonparametric tests were used to compare the outcome groups. RESULTS: Forty four (12%) of 370 included patients had a cardiac thrombus on admission CTA: 35 (9%) in the left atrial appendage and 14 (4%) in the left ventricle. Patients with cardiac thrombus had more severe strokes (median National Institutes of Health Stroke Scale score, 10 versus 4; P=0.006), had higher clot burden (median clot burden score, 9 versus 10; P=0.004), and underwent endovascular treatment more often (43% versus 20%; P<0.001) than patients without cardiac thrombus. Left atrial appendage thrombus was present in 28% and 6% of the patients with and without atrial fibrillation, respectively ( P<0.001). The diagnostic certainty for left atrial appendage thrombus was higher for spectral iodine maps compared with the conventional CTA ( P<0.001). The presence of cardiac thrombus on CTA increased the likelihood of a cardioembolic source according to the expert panel ( P<0.001). CONCLUSIONS: Extending the stroke CTA to cover the heart increases the chance of detecting cardiac thrombi and helps to identify cardioembolic sources in the acute stage of ischemic stroke with more certainty. Spectral iodine maps provide additional value for detecting left atrial appendage thrombus. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04019483
Recycling of CO2, the perfect biofuel?
SUMMARY
Most of the fossil fuels are currently used for transportation, to generate electricity or used for heating purposes. Mainly due to the increasing world population and the economic development of countries, the energy demand will increase rapidly. If society will still use fossil fuels in the future to supply this demand, we are going to be faced with major fossil fuel shortfalls and increasing CO2 emissions. The Icelandic company Carbon Recycling International (CRI) think they have the answer for both major global problems and developed a way to recycle CO2 into biofuel, which can act as a replacement for fossil fuels. CRI only uses geothermal power, water and CO2 to convert this in methanol. They claim that, on a short term, this technique can replace fossil fuels and they think it is possible to decrease CO2 emissions to pre-industrial levels. But is it technically possible to recycle CO2 and are the claims of CRI correct?
An important fact is that also hydrogen is required to convert CO2 to methanol. Converting CO2 into methanol is not a new technique and already developed by BASF in 1905 when CO2 and hydrogen were obtained from fermentation gases. What is new is the way of producing hydrogen with the electrolysis of water and capturing CO2 by only using geothermal power. Iceland has a large potential of geothermal and hydropower. Furthermore, CO2 can efficiently be captured from geothermal power plants. Both reasons, give CRI the opportunity to produce large amounts of renewable methanol.
Only electricity is required to convert CO2 to methanol. Unfortunately, the total energy efficiency from electricity to methanol is relatively low with 42 up to 55%. This depends on where the process is located, how CO2 is captured and how the electricity is generated (geothermal, solar, wind et cetera). In this process, CO2 is basically a temporary feedstock because, with the combustion of methanol itself, captured CO2 will be released again. Therefore, no CO2 will be recycled by CRI. The situation is even worse, it will cost CO2 when new geothermal power plants are used to produce renewable methanol.
The only realistic option to recycle CO2 is when it is captured from fossil fuel power plants or from industry. In this situation, captured CO2 is converted to methanol and with the use of this methanol, the same amount of CO2 will be released again. The best option that CRI can achieve is to create a closed-loop of CO2 when it is captured from atmospheric air. This means, when it is applied on a large scale, it can actually stabilize CO2 level. However, it is untrue that CO2 levels could decrease to pre-industrial levels. Also too few information is available about the actual energy consumption of a large scale implementation of this kind of methanol production.
The total potential of Iceland is not large. Using the maximum available geothermal power and CO2, the potential is limited up to about 350 million litres of methanol a year. This is large enough to supply the Icelandic demand of methanol when this is used as a replacement for conventional gasoline in passenger cars. Exporting this amount to the Netherlands would not even supply 3% of all gasoline cars in the Netherlands. The potential could be five times larger when also potential hydropower is used and extra CO2 is captured from the industry. In this case, CO2 will be recycled but the potential is still relatively small. Furthermore, the production costs will be even higher than the current estimated production price of 600-1200 euro/ton of methanol in combination with old geothermal power or hydropower plants. To compete with the current fossil fuel-based methanol market prices of 300 euro/ton, the production of renewable methanol has not to be taxed or the production has to be subsidised.
When this methanol process is applied on a global scale, the maximum potential of geothermal power could almost replace current demand of methanol. This would actually save about 30 Mton of CO2 a year, which is about 0.1% of all annual global CO2 emissions. Unfortunately, the second claim of CRI is also not true. The use of only the available geothermal power and CO2 cannot replace the global demand for fossil fuels.
A positive fact about this technique is that it can store electricity and can therefore function as a potential energy buffer. If a country tries to install unpredictable and variable renewable energy sources such as wind and solar, at some moments, more electricity can be generated than is actually needed. This oversupply can be used to produce methanol to buffer energy. The most ambitious plan of the Dutch government is to implement 6 GWe offshore wind, 4 GWe onshore wind and 4 GWe of solar PVs by the year 2030. When this scenario is simulated in PowerPlan (a medium term program that simulate the electricity supply and demand of a country), the result is that the oversupply of electricity in the Netherlands is too small. Besides renewables, the Netherlands also invests in more flexible fossil fuel power plants. These will be used to minimize the occurrence of a electricity oversupply. Therefore, methanol production in the Netherlands by the year 2030 cannot advantageously be used as a potential energy buffer. Perhaps it can be used in countries such as Germany that are trying to invest more in solar and wind power and are therefore faced with larger electricity oversupplies than the Netherlands.
Option for a sustainable passenger transport sector in 2050
SUMMARY
The current transport sector faces two global problems. The first is climate change, due to the combustion of fossil fuels, and the second is resource depletion. From the entire transport sector (road, air and water), private passenger vehicles account for more than 50% of the emitted greenhouse gasses. The main question is: will there be a sustainable solution for private passenger vehicles in 2050? The aim of this research is to find potential bottlenecks when the entire society switches to one singe alternative. For example when we will still be using the Internal Combustion Engine (ICE) in 2050 or when we all switch to Battery Electric Vehicles (BEV), Fuel Cell Electric Vehicles (FCEV), Biofuel vehicle or perhaps a combination in the form of a Hybrid vehicle.
The definition of a sustainable situation is not to rely on fossil fuels and the demand for resources (material, land, renewable energy) is not larger than the reserves or potential. Current CO2 emissions (3500 Mton/yr) from the private passenger vehicle sector are expected to increase by a factor 2 according to the business-as-usual (BAU) scenario. In this scenario, the total amount of vehicles will increase to about 2 billion and the global travelled distances will increase with a factor of 2.3 by the year 2050. A sustainable CO2 situation is a reduction of 50% compared to the 1990 levels, which means 1175 Mt/yr. With the use of fore- and backcasting scenarios, the most important bottlenecks of each alternative are examined.
Improving ICE vehicles, for example with direct injection, mass reduction, engine downsizing, variable gearboxes, decreases resource use and total CO2 emissions by more than 50%. Unfortunately, these measures can only stabilize current CO2 emissions in 2050, due to the increase in global travelled kilometers. Furthermore, these vehicles still use fossil fuels. Improved ICE vehicles cannot become a sustainable solution in 2050. When biofuels substitute fossil fuels, ICE vehicles are much cleaner. The potential of 1st generation biofuels is technically large enough to cover the demand, but emissions of producing it vary enormously and therefore these vehicles cannot become sustainable in 2050. The potential of 2nd generation biofuels is unfortunately smaller and is therefore not enough to cover the demand.
Electric vehicles store their energy in NGA-G lithium batteries (BE vehicles) or in hydrogen (FCE vehicles). The main bottlenecks of BE vehicles are the relatively low energy density of batteries, the accumulated lithium demand and the CO2 intensity of current electricity production. The lithium reserves are only large enough to produce BE vehicles with a battery that can cover a vehicle range of 400-500 km. Charging these batteries with the current electricity mix would only stabilize current CO2 emissions in 2050. These vehicles can only become sustainable when at least 80% of the electricity is generated by renewable electricity sources. FCE vehicles do not have a direct resource bottleneck but faces an overall low efficiency (hydrogen production, transport and fuel cell efficiency) of 30%. For these vehicles, at least 90% of the electricity has to be generated by renewable electricity sources. Both are within the potential of renewable electricity sources such as wind, water and solar power but large investments have to be made to supply this demand.
A Plug-in hybrid electric vehicle (PHEV) is a combination of a BE vehicle and a combustion engine to extent the range (<800 km). 82% of all the annually travelled distances can be covered by the electric powertrain with a relatively small battery (3.2 kWh = 48km vehicle range). Therefore the accumulated demand for lithium would be only 2.2 Mt and can easily be covered by the available reserves bases (32.5 Mt). However, the CO2 bottlenecks still remain. Emissions from the ICE powertrain are relatively high and the current electricity mix is not clean enough to charge these batteries in a sustainable way. A solution is that biofuels are used in the ICE powertrain and that the batteries are charged by renewable electricity sources. The advantage of PHE vehicles is the limited demand for lithium, biofuels and renewable electricity sources.
Current implementation of the researched alternatives will not give a sustainable situation right now. Therefore something structural has to be changed, for example the CO2 intensity of current electricity production. PHE vehicles are the best choice for a sustainable passenger transport sector by the year 2050 because of the limited demand of resources that can be covered by the potentials and reserves. A discussion point is that the estimation of lithium reserves has more than doubled in the last two years. Electric vehicles are more energy efficient than a PHE vehicle in combination with biofuels. The actual available lithium reserves are not well known and therefore maybe BE vehicles are the best choice for a sustainable passenger transport sector. Either way, renewable electricity sources are needed to achieve a sustainable private passenger vehicle sector in 2050.
Green methanol from hydrogen and carbon dioxide using geothermal energy and/or hydro power in Iceland or excess renewable electricity in Germany
The synthesis of green methanol from hydrogen and carbon dioxide can contribute to mitigation of greenhouse gasses. This methanol can be utilized as either a transport fuel or as an energy carrier for electricity storage. It is preferable to use inexpensive, reliable and renewable energy sources to provide the energy needed for the green methanol production. Iceland has a large potential for such renewable energy sources. If only geothermal CO2 may be utilized the green methanol potential in Iceland is 340 million L/y. When all the potentially available geothermal energy and hydro power is combined the potential becomes 2150 million L/y. Next the scope is broadened to the European mainland using Germany as a case since its government has set strict goals for renewable electricity production. For Germany the electricity oversupply in 2050 is predicted to be 24 TWhe/y, leading to a methanol potential of 2350 million L/y using CO2 from fossil fuel power plants. In Iceland the potential of 340 million L/y of methanol as a transport fuel would supply all of the M3 demand and 75% of the M85 demand. In Germany the electricity oversupply would provide all of the M3 demand but only 4% of the M85 demand