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Search Results: 1 - 10 of 739 matches for " Mikko Taina "
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Left Atrial Appendage Volume Increased in More Than Half of Patients with Cryptogenic Stroke
Mikko Taina, Ritva Vanninen, Marja Hedman, Pekka J?k?l?, Satu K?rkk?inen, Tero Tapiola, Petri Sipola
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079519
Abstract: Background Ischemic strokes without a well-defined etiology are labeled as cryptogenic, and account for 30–40% of strokes in stroke registries. The left atrial appendage (LAA) is the most typical origin for intracardiac thrombus formation when associated with atrial fibrillation. Here, we examined whether increased LAA volume detected with cardiac computed tomography (cCT) constitutes a risk factor in cryptogenic stroke patients. Methods This study included 82 stroke/TIA patients (57 males; mean age, 58 years) with a diagnosis of cryptogenic stroke after extensive radiological and cardiological investigations. Cases were classified using the TOAST criteria modified by European Association of Echocardiography recommendations for defining cardiac sources of embolism. Forty age- and gender-matched control subjects without cardiovascular diseases were selected for pair-wise comparisons (21 males; mean age, 54 years). LAA volume adjusted for body surface area was measured three dimensionally by tracing the LAA borders on electrocardiogram-gated CT slices. Results In control subjects, mean LAA volume was 3.4±1.1 mL/m2. Mean+2SD, which was considered the upper limit for normal LAA volume was 5.6 mL/m2. In paired Student t-test between the patient group and matched controls, LAA volume was 67% larger in cryptogenic stroke/TIA patients (5.7±2.0 mL/m2 vs. 3.4±1.1 mL/m2; P<0.001). Forty-five (55%) patients with cryptogenic stroke/TIA had enlarged LAA. Conclusion LAA is significantly enlarged in more than half of patients with cryptogenic stroke/TIA. LAA thrombosis may contribute to the pathogenesis of stroke in patients considered to have cryptogenic stroke after conventional evaluation.
Determinants of Left Atrial Appendage Volume in Stroke Patients without Chronic Atrial Fibrillation
Mikko Taina, Petri Sipola, Antti Muuronen, Marja Hedman, Pirjo Mustonen, Anne-Mari Kantanen, Pekka J?k?l?, Ritva Vanninen
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090903
Abstract: Background Left atrial appendage (LAA) volume has been shown to be increased in patients with acute cryptogenic stroke. Atrial fibrillation (AF) is a well-recognized risk factor but it is not the only one associated with LAA enlargement. The aim of the study was to clarify the multifactorial etiology of LAA enlargement in cardiogenic stroke/TIA patients without AF. Methods Altogether 149 patients with suspected cardioembolic stroke/TIA (47 females; mean age 61 years) underwent cardiac CT. Diagnosed AF on admittance was an exclusion criteria but 24-hour Holter ambulatory ECG revealed paroxysmal AF (PAF) in 20 patients. Body surface area adjusted LAA volume was evaluated. Eighteen different variables were registered including general characteristics, definite and potential causal risk factors for ischemic stroke/TIA, clinical echoparameters and CT based cardiac volumetric and adipose tissue measurements. A stepwise linear regression analysis was performed to achieve a model adjusted for the number of predictors of LAA volume increase. Results In linear regression analysis, the best model accounted for 30% of the variability in LAA volume, including PAF (19%) and enlarged left atrial volume (6%), enlarged left ventricle end-systolic diameter (3%) and decreased pericardial adipose tissue (2%). No multi-colinearity between variables was observed. In addition to PAF, no other definitive or potential causal risk factors could account for the LAA volume in these patients. Conclusions LAA volume increase seems to be poorly associated with currently known stroke/TIA risk factors, except for AF. Targeting more comprehensive ECG monitoring for stroke patients with increased LAA volume should be considered.
Morphological and Volumetric Analysis of Left Atrial Appendage and Left Atrium: Cardiac Computed Tomography-Based Reproducibility Assessment
Mikko Taina, Miika Korhonen, Mika Haataja, Antti Muuronen, Otso Arponen, Marja Hedman, Pekka J?k?l?, Petri Sipola, Pirjo Mustonen, Ritva Vanninen
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0101580
Abstract: Objectives Left atrial appendage (LAA) dilatation and morphology may influence an individual's risk for intracardiac thrombi and ischemic stroke. LAA size and morphology can be evaluated using cardiac computed tomography (cCT). The present study evaluated the reproducibility of LAA volume and morphology assessments. Methods A total of 149 patients (47 females; mean age 60.9±10.6 years) with suspected cardioembolic stroke/transient ischemic attack underwent cCT. Image quality was rated based on four categories. Ten patients were selected from each image quality category (N = 40) for volumetric reproducibility analysis by two individual readers. LAA and left atrium (LA) volume were measured in both two-chamber (2CV) and transversal view (TV) orientation. Intertechnique reproducibility was assessed between 2CV and TV (200 measurement pairs). LAA morphology (A = Cactus, B = ChickenWing, C = WindSock, D = CauliFlower), LAA opening height, number of LAA lobes, trabeculation, and orientation of the LAA tip was analysed in all study subjects by three individual readers (447 interobserver measurement pairs). The reproducibility of volume measurements was assessed by intra-class correlation (ICC) and the reproducibility of LAA morphology assessments by Cohen's kappa. Results The intra-observer and interobserver reproducibility of LAA and LA volume measurements was excellent (ICCs>0.9). The LAA (ICC = 0.954) and LA (ICC = 0.945) volume measurements were comparable between 2CV and TV. Morphological classification (? = 0.24) and assessments of LAA opening height (? = 0.1), number of LAA lobes (? = 0.16), trabeculation (? = 0.15), and orientation of the LAA tip (? = 0.37) was only slightly to fairly reproducible. Conclusions LA and LAA volume measurements on cCT provide excellent reproducibility, whereas visual assessment of LAA morphological features is challenging and results in unsatisfactory agreement between readers.
Reorganization of functionally connected brain subnetworks in high-functioning autism
Enrico Glerean,Raj Kumar Pan,Juha Salmi,Rainer Kujala,Juha Lahnakoski,Ulrika Roine,Lauri Nummenmaa,Sami Lepp?m?ki,Taina Nieminen-von Wendt,Pekka Tani,Jari Saram?ki,Mikko Sams,Iiro P. J??skel?inen
Quantitative Biology , 2015,
Abstract: Background: Previous functional connectivity studies have found both hypo- and hyper-connectivity in brains of individuals having autism spectrum disorder (ASD). Here we studied abnormalities in functional brain subnetworks in high-functioning individuals with ASD during free viewing of a movie containing social cues and interactions. Methods: Thirteen subjects with ASD and 13 matched-pair controls watched a 68 minutes movie during functional magnetic resonance imaging. For each subject, we computed Pearson`s correlation between haemodynamic time-courses of each pair of 6-mm isotropic voxels. From the whole-brain functional networks, we derived individual and group-level subnetworks using graph theory. Scaled inclusivity was then calculated between all subject pairs to estimate intersubject similarity of connectivity structure of each subnetwork. Additional 27 individuals with ASD from the ABIDE resting-state database were included to test the reproducibility of the results. Results: Between-group differences were observed in the composition of default-mode and a ventro-temporal-limbic (VTL) subnetwork. The VTL subnetwork included amygdala, striatum, thalamus, parahippocampal, fusiform, and inferior temporal gyri. Further, VTL subnetwork similarity between subject pairs correlated significantly with similarity of symptom gravity measured with autism quotient. This correlation was observed also within the controls, and in the reproducibility dataset with ADI-R and ADOS scores. Conclusions: Reorganization of functional subnetworks in individuals with ASD clarifies the mixture of hypo- and hyper-connectivity findings. Importantly, only the functional organization of the VTL subnetwork emerges as a marker of inter-individual similarities that co-vary with behavioral measures across all participants. These findings suggest a pivotal role of ventro-temporal and limbic systems in autism.
A New Fairness-Oriented Packet Scheduling Scheme with Reduced Channel Feedback for OFDMA Packet Radio Systems  [PDF]
Stanislav NONCHEV, Mikko VALKAMA
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.27068
Abstract: In this paper, we propose a flexible and fairness-oriented packet scheduling approach for 3GPP UTRAN long term evolution (LTE) type packet radio systems, building on the ordinary proportional fair (PF) scheduling principle and channel quality indicator (CQI) feedback. Special emphasis is also put on practical feedback reporting mechanisms, including the effects of mobile measurement and estimation errors, reporting delays, and CQI quantization and compression. The performance of the overall scheduling and feedback re-porting process is investigated in details, in terms of cell throughput, coverage and resource allocation fairness, by using extensive quasistatic cellular system simulations in practical OFDMA system environment with frequency reuse of 1. The performance simulations show that by using the proposed modified PF ap-proach, significant coverage improvements in the order of 50% can be obtained at the expense of only 10-15% throughput loss, for all reduced feedback reporting schemes. This reflects highly improved fairness in the radio resource management (RRM) compared to other existing schedulers, without essentially com-promising the cell capacity. Furthermore, we demonstrate the improved functionality increase in radio re-source management for UE’s utilizing multi-antenna diversity receivers.
Constant Power Model in Arm Rotation—A New Approach to Hill’s Equation  [PDF]
Ahti Rahikainen, Mikko Virmavirta
World Journal of Mechanics (WJM) , 2014, DOI: 10.4236/wjm.2014.46018
Abstract:

The purpose of this study was to further develop the constant power model of a previous study and to provide the final solution of Hill’s force-velocity equation. Forearm and whole arm rotations of three different subjects were performed downwards (elbow and shoulder extension) and upwards (elbow and shoulder flexion) with maximum velocity. These arm rotations were recorded with a special camera system and the theoretically derived model of constant maximum power was fitted to the experimentally measured data. The moment of inertia of the arm sectors was calculated using immersion technique for determining accurate values of friction coefficients of elbow and whole arm rotations. The experiments of the present study verified the conclusions of a previous study in which theoretically derived equation with constant maximum power was in agreement with experimentally measured results. The results of the present study were compared with the mechanics of Hill’s model and a further development of Hill’s force-velocity relationship was derived: Hill’s model was transformed into a constant maximum power model consisting of three different components of power. It was concluded that there are three different states of motion: 1) the state of low speed, maximal acceleration without external load which applies to the hypothesis of constant moment; 2) the state of high speed, maximal power without external load which applies to the hypothesis of constant power and 3) the state of maximal power with external load which applies to Hill’s equation. This is a new approach to Hill’s equation.

Music as a recorder of mentalities
Mikko Salasuo
Nordic Studies on Alcohol and Drugs , 2011, DOI: 10.2478/v10199-011-0032-1
Abstract:
Kalevalam du varasem ajalugu
Mikko Korhonen
M?etagused. Hüperajakiri , 1999,
Abstract: The main point of Mikko Korhonen's article The Early Historyà is that several questions of the origin of the Kalevala metre have not yet been thoroughly studied from the aspect of historical linguistics. According to the commonly accepted argument the metrical systems used in language and folklore in particular have formed in accordance with the prosodic features of the language. Therefore, the consideration of scientific research in linguistic history has a significant role in the formation as well as the development of Kalevala metre. From the grounds of the historical prosody of languages and the characteristic features of folklore Mikko Korhonen views the arguments of several earlier researchers in a new light and argues that the metre of ancient songs of the Finnnish people cannot have the same origin as the syllable metres of Mordvin, that it is not of Baltic origin or the result of Baltic influence, but that it emerged as a spontaneous reaction to the phonetic and prosodic development of Proto-Finnic.
Thomas Hobbes on Revolution
Mikko Jakonen
La Révolution Fran?aise : Cahiers de l’Institut d’Histoire de la Révolution Fran?aise , 2011,
Abstract: La dénomination des Guerres civiles anglaises est un objet de débat entre historiens depuis l’époque des faits eux-mêmes. Selon les inclinations politiques de chacun, elles ont tour à tour été appelées “la Révolution puritaine” (the Puritan Revolution), “la Grande Rebellion” (the Great Rebellion), ou tout simplement “les Guerres civiles anglaises” (the English Civil Wars). Cependant, une autre question, plus problématique, enrobe la terminologie de ces événements.Tandis que certains historiographes les envisagent comme une série de ruptures au sein de la société anglaise, d’autres qualifient la période toute entière de révolution. Toutefois, le concept de révolution n’existait pas au XVIIe siècle – du moins pas dans son sens contemporain. Le recours aux outils de l’histoire conceptuelle, appliqués au concept de révolution présent dans la théorie politique de Thomas Hobbes, permet de poser des questions fondamentales à l’historiographie des Guerres civiles anglaises. En particulier, il est possible de s’interroger sur les recherches consacrées à Hobbes qui envisagent les Guerres civiles anglaises comme une révolution et le voient comme un auteur révolutionnaire. Cet article entend adopter une approche plus sensible de l’histoire des idées politiques qui admette la fluctuation du sens des concepts historiques.
Spaces and Places of Cultural Studies
Mikko Lehtonen
Culture Unbound : Journal of Current Cultural Research , 2009,
Abstract: As cultural studies has sought for a foothold in universities, it has faced pressures of modern disciplinarity it aims at to challenge and alter. In the conjuncture of neo-liberal university policies new weight is given to multidisciplinarity as an instrument for reshaping universities in favour of cost-effectiveness and quick-fix applications. In this new situation cultural studies has to defend purposeful and enduring diversity in and of universities. In order to be able to do this it has to think of itself not only as a critical space but also as such place where universities could critically reflect themselves and their place in the world.
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