Particle and NOx emissions from a HVO-fueled diesel engine

Concerns about oil price, the strengthening climate change and traffic related health effects are all reasons which have promoted the research of renewable fuels. One renewable fuel candidate is diesel consisting of hydrotreated vegetable oils (HVO). The fuel is essentially paraffinic, has high cetane number (>80) and contains practically no oxygen, aromatics or sulphur. Furthermore, HVO fuel can be produced from various feedstocks including palm, soybean and rapeseed oils as well as animal fats. HVO has also been observed to reduce all regulated engine exhaust emissions compared to conventional diesel fuel. In this thesis, the effect of HVO fuel on engine exhaust emissions has been studied further. The thesis is roughly divided into two parts. The first part explores the emission reductions associated with the fuel and studies techniques which could be applied to achieve further emission reductions. One of the studied techniques was adjusting engine settings to better suit HVO fuel. The settings chosen for adjustments were injection pressure, injection timing, the amount of EGR and the timing of inlet valve closing (with constant inlet air mass flow, i.e. Miller timing). The engine adjustments were also successfully targeted to reduce either NOx or particulate emissions or both. The other applied emission reduction technique was the addition of oxygenate to HVO fuel. The chosen oxygenate was di-n-pentyl ether (DNPE), and tested fuel blend included 20 wt-% DNPE and 80 wt-% HVO. Thus, the oxygen content of the resulting blend was 2 wt-%. Reductions of over 25 % were observed in particulate emissions with the blend compared to pure HVO while NOx emissions altered under 5 %. On the second part of this thesis, the effect of the studied fuels on chosen surface properties of exhaust particles were studied using tandem differential mobility analyzer (TDMA) techniques and transmission electron microscopy (TEM). The studied surface properties were oxidizability and hygroscopicity. The oxidation properties were compared between soot particles emitted with HVO and with conventional diesel. The effects of fuel on hygroscopicity, on the other hand, were compared between HVO and oxygenated HVO fuel. In general, no considerable differences were observed in the exhaust particle surface properties due to the change of fuel

Experimental Investigation of Angular Stackgram Filtering for Noise Reduction of SPECT Projection Data: Study with Linear and Nonlinear Filters

We discuss data filtering prior to image reconstruction. For this kind of filtering, the radial direction of the sinogram is routinely employed. Recently, we have introduced an alternative approach to sinogram data processing, exploiting the angular information in a novel way. This new stackgram representation can be regarded as an intermediate form of the sinogram and image domains. In this experimental study, we compare the radial sinogram and angular stackgram filtering methods using physical SPECT phantoms. Our study is carried out by employing simple linear and nonlinear filters with ten different Gaussian kernels, in order to provide a comparable investigation. According to our results, angular stackgram filtering with the nonlinear filters provides the best resolution-noise tradeoff of the compared methods. Besides, stackgram filtering with these filters seems to preserve the resolution in an exceptional way. Visually, noise in the reconstructed images after stackgram filtering appears more “powdery” in comparison with radial sinogram filtering

Lapselle tai nuorelle psyykenlääkitys - milloin tutkitaan EKG?

Vertaisarvioitu. English summary.• EKG:n tutkiminen ei ole tarpeen aloitettaessa psyykenlääkitystä lapselle tai nuorelle, jos sairaushistoria, statuslöydökset ja sukuanamneesi ovat normaalit. • Tarpeettomista EKG-tutkimuksista voi aiheutua potilaille ja perheille turhaa huolta, ja tarpeellisen hoidon aloitus saattaa viivästyä. • Jos käytetään samanaikaisesti useita psyykenlääkkeitä tai muita QT-aikaa pidentäviä lääkkeitä, EKG on hyvä tarkistaa. • Leikattu sydänvika tai perinnöllinen sydänlihas- tai rytmihäiriösairaus ei välttämättä ole esteenä ¬lääkityksille, mutta hoitavan kardiologin konsultaatio on aiheellinen

Elektrofysiologian uutuudet nopeiden rytmihäiriöiden diagnosoinnissa ja hoidossa

Vertaisarvioitu. Teema : lastenkardiologia. English summaryPeer reviewe

Automatic Atrial Threshold Measurement and Adjustment in Pediatric Patients

Background: Automatic threshold measurement and output adjustment are used as default settings in modern pacemakers. The purpose of the study was to assess Atrial Capture Management (ACM) of Medtronic pacemakers in pediatric patients. Methods: Forty children were enrolled in two centers. Median age was 9.8 years (range 0.8–17.5 years). Half had undergone surgery for congenital heart defects; 45% of patients had an epicardial atrial lead. The pacing indication was atrioventricular block in 82% of patients and sinus node disease in 18%. Manually determined atrial thresholds and ACM measurements were compared. Results: ACM measurements were within the expected variation in 37/40 (93%) of the patients. In one patient the threshold was 0.625-V lower manually than with ACM. One patient had too high an intrinsic atrial rate for ACM to be able to measure threshold. The mean threshold at 0.4 ms was 0.69 ± 0.32 V manually and 0.68 ± 0.35 V with ACM (two-tailed paired t- test, P = 0.52) in all patients. The mean difference was 0.012 V (95% confidence interval: −0.027, 0.053). The mean endocardial threshold was 0.70 ± 0.36 V manually and 0.69 ± 0.38 V with ACM; epicardial threshold was 0.67 ± 0.27 V manually and 0.68 ± 0.32 V with ACM. The difference between the measurements was 0.012 V for endocardial and 0.014 V for epicardial leads. No atrial arrhythmias due to ACM measurements were observed. Conclusions: ACM measures atrial thresholds reliably in pediatric patients with both endocardial and epicardial leads, allowing its use in both. Constant high intrinsic atrial rate may prevent automatic threshold measurement in young children. (PACE 2010; 33:309–313)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79326/1/j.1540-8159.2009.02619.x.pd

Multicenter cohort study on duration of antiarrhythmic medication for supraventricular tachycardia in infants

Antiarrhythmic medication (AM) is commonly used to prevent supraventricular tachycardia (SVT) recurrence in infants. Our aim was to determine whether a shorter duration of AM is sufficient to prevent atrioventricular reentrant tachycardia (AVRT) recurrence and evaluate risk factors for recurrence of SVT after discontinued AM.This multicenter cohort study included all infants diagnosed with SVT in the five university hospitals in Finland between 2005 and 2017. Those diagnosed between 2005 and 2012 received AM for 12 months (group 1), and those diagnosed between 2013 and 2017 received AM for 6 months (group 2). A total of 278 infants presented with AVRT (group 1, n = 181; group 2, n = 97), and the median AM duration was 12.0 months (interquartile range [IQR] 11.4-13.4) and 7.0 months (IQR 6.0-10.2), respectively. Propranolol was the most frequently used first-line AM (92% and 95%). Recurrence-free survival rates were over 88% until 12 months after AM prophylaxis in both groups, without any statistically significant difference between them. Independent risk factors for recurrence of SVT after discontinuation of AM were need of combination AM (HR 2.2, 95% CI 1.14-4.20), Wolff-Parkinson White (WPW) syndrome (HR 2.4, 95% CI 1.25-4.59), and age over 1 month at admission (HR 2.2, 95% CI 1.12-4.48). Conclusion: Shortening AM duration in infants from 12 to 6 months does not seem to lead to more frequent SVT recurrence. The risk factors for recurrence of SVT were WPW syndrome, need of combination AM, and age over 1 month.Peer reviewe

Long-term outcome after treatment of pulmonary atresia with ventricular septal defect : nationwide study of 109 patients born in 1970-2007

OBJECTIVES: Treatment of pulmonary atresia with ventricular septal defect (PA + VSD) has evolved during recent decades, but it still remains challenging. This study evaluated 41-year experience of outcome, survival and treatment of PA + VSD patients. METHODS: Patient records and angiograms of 109 patients with PA + VSD born in Finland between 1970 and 2007, and treated at the Children's Hospital, Helsinki University Central Hospital, were retrospectively analysed in this nationwide study. RESULTS: Of the 109 patients, 66 (61%) had simple PA + VSD without major aortopulmonary collateral arteries (MAPCAs). Although we observed no difference in overall survival between those with or without MAPCAs, the patients without MAPCAs had better probability to achieve repair (64 vs 28%, P <0.0003). Only 3 patients were treated by compassionate care. Overall survival was affected by the size of true central pulmonary arteries on the first angiogram (P = 0.001) and whether repair was achieved (P <0.0001). After successful repair, the survival rate was 93% at 1 year, 91% from the second year, and functional capacity as assessed by New York Heart Association (NYHA) I-II remained in 85% of patients alive at the end of follow-up. Palliated patients at 1, 5, 10 and 20 years of age had Kaplan-Meier estimated survival rates of 55, 42, 34 and 20%, respectively. Patients who underwent repair attempts but were left palliated with right ventricle (RV)-pulmonary artery connection and septal fenestration had better survival than the rest of the palliated patients (P = 0.001). Further, the McGoon index improved after implementation of a systemic-pulmonary artery shunt in the overall PA + VSD population (P <0.0001). CONCLUSIONS: These findings show that achievement of repair and initial size of true central pulmonary arteries affect survival of patients with PA + VSD. Although the overall survival of patients with MAPCAs showed no difference compared with simple PA + VSD patients, they had a higher risk of remaining palliated. However, palliative surgery may have a role in treatment of PA + VSD because the size of pulmonary arteries increased after placement of systemic-pulmonary artery shunt. In addition, subtotal repair by a RV-pulmonary artery connection and septal fenestration improved survival over extracardiac palliation.Peer reviewe

Indications and management of implantable cardioverter-defibrillator therapy in childhood hypertrophic cardiomyopathy

Sudden cardiac death is the most common mode of death during childhood and adolescence in hypertrophic cardiomyopathy, and identifying those individuals at highest risk is a major aspect of clinical care. The mainstay of preventative therapy is the implantable cardioverter-defibrillator, which has been shown to be effective at terminating malignant ventricular arrhythmias in children with hypertrophic cardiomyopathy but can be associated with substantial morbidity. Accurate identification of those children at highest risk who would benefit most from implantable cardioverter-defibrillator implantation while minimising the risk of complications is, therefore, essential. This position statement, on behalf of the Association for European Paediatric and Congenital Cardiology (AEPC), reviews the currently available data on established and proposed risk factors for sudden cardiac death in childhood-onset hypertrophic cardiomyopathy and current approaches for risk stratification in this population. It also provides guidance on identification of individuals at risk of sudden cardiac death and optimal management of implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy

Future Combustion Technology for Synthetic and Renewable Fuels in Compression Ignition Engines (REFUEL) - Final report

This domestic project, Future Combustion Technology for Synthetic and Renewable Fuels in Compression Ignition Engines (ReFuel), was part of a Collaborative Task "Future Combustion Technology for Synthetic and Renewable Fuels in Transport" of International Energy Agency (IEA) Combustion Agreement. This international Collaborative Task is coordinated by Finland. The three-year (2009-2011) project was a joint research project with Aalto University (Aalto), Tampere University of Technology (TUT), Technical Research Centre of Finland (VTT) and Åbo Akademi University (ÅAU). The project was funded by TEKES, Wärtsilä Oyj, Neste Oil Oyj, Agco Sisu Power, Aker Arctic Technology Oy and the research partners listed above. Modern renewable diesel fuels have excellent physical and chemical properties, in comparison to traditional crude oil based fuels. Purely paraffinic fuels do not contain aromatic compounds and they are totally sulphur free. Hydrotreated Vegetable Oil (HVO) was studied as an example of paraffinic high cetane number (CN) diesel fuels. HVO has no storage and low temperature problems like the fatty acid methyl esters (FAMEs) have. The combustion properties are better than those of crude oil based fuels and FAME, because they have very high cetane numbers and contain no polyaromatic hydrocarbons (PAH). With low HVO density, viscosity and distillation temperatures, these advantageous properties allow far more advanced combustion strategies, such as very high exhaust gas recirculation (EGR) rates or extreme Miller timings, than has been possible with current fossil fuels. The implementation of these advanced combustion technologies, together with the novel renewable diesel fuel, brought significant nitrogen oxides (NOx), particulate matter (PM) emission reductions with no efficiency losses. The objective of ReFuel project was to develop new extremely low emission combustion technologies for new renewable fuels in compression ignition engines. The target was to decrease emissions at least by 70%. The scope was to utilize the physical and chemical properties of the renewable fuels that differ from properties of the traditional crude oil based fuels and to develop optimum combustion technologies for them. The project focused firstly, on paraffinic high cetane number fuels i.e. hydrotreated vegetable oil fuel as a typical representative of this kind of fuel and secondly, on fuels with high content of oxygenates. This was implemented by blending oxygenate to HVO fuel.