Determinants of vascular cognitive impairment : White matter lesions, brain atrophy and their neuropsychological correlates

The concept of vascular cognitive impairment (VCI) covers a wide spectrum of cognitive dysfunctions related to cerebrovascular disease. Among the pathophysiological determinants of VCI are cerebral stroke, white matter lesions and brain atrophy, which are known to be important risk factors for dementia. However, the specific mechanisms behind the brain abnormalities and cognitive decline are still poorly understood. The present study investigated the neuropsychological correlates of particular magnetic resonance imaging (MRI) findings, namely, medial temporal lobe atrophy (MTA), white matter hyperintensities (WMH), general cortical atrophy and corpus callosum (CC) atrophy in subjects with cerebrovascular disease. Furthermore, the cognitive profile of subcortical ischaemic vascular disease (SIVD) was examined. This study was conducted as part of two large multidisciplinary study projects, the Helsinki Stroke Aging Memory (SAM) Study and the multinational Leukoaraiosis and Disability (LADIS) Study. The SAM cohort consisted of 486 patients, between 55 and 85 years old, with ischaemic stroke from the Helsinki University Hospital, Helsinki, Finland. The LADIS Study included a mixed sample of subjects (n=639) with age-related WMH, between 65 and 84 years old, gathered from 11 centres around Europe. Both studies included comprehensive clinical and neuropsychological assessments and detailed brain MRI. The relationships between the MRI findings and the neuropsychological test performance were analysed by controlling for relevant confounding factors such as age, education and other coexisting brain lesions. The results revealed that in elderly patients with ischaemic stroke, moderate to severe MTA was specifically related to impairment of memory and visuospatial functions, but mild MTA had no clinical relevance. Instead, WMH were primarily associated with executive deficits and mental slowing. These deficits mediated the relationship between WMH and other, secondary cognitive deficits. Cognitive decline was best predicted by the overall degree of WMH, whereas the independent contribution of regional WMH measures was low. Executive deficits were the most prominent cognitive characteristic in SIVD. Compared to other stroke patients, the patients with SIVD also presented more severe memory deficits, which were related to MTA. The cognitive decline in SIVD occurred independently of depressive symptoms and, relative to healthy control subjects, it was substantial in severity. In stroke patients, general cortical atrophy also turned out to be a strong predictor of cognitive decline in a wide range of cognitive domains. Moreover, in elderly subjects with WMH, overall CC atrophy was related to reduction in mental speed, while anterior CC atrophy was independently associated with frontal lobe-mediated executive functions and attention. The present study provides cross-sectional evidence for the involvement of WMH, MTA, general cortical atrophy and CC atrophy in VCI. The results suggest that there are multifaceted pathophysiological mechanisms behind VCI in the elderly, including both vascular ischaemic lesions and neurodegenerative changes. The different pathological changes are highly interrelated processes and together they may produce cumulative effects on cognitive decline.

Käsityksistä ajatuksen poluille : Ammattikorkeakoulun tutkimus- ja kehitystoiminnan kehittäminen

This study deals with the formation of the idea of research and development (r&d) activity at one particular university of applied sciences in Finland. In this study I proceed from examining the conceptions of management regarding r&d-activities to exploring the development of the complex concept that guides these r&d-activities. The aim of this study is, first, to describe conceptions of r&d-activities, and then, second, to describe the formation of a new concept for r&d-activities in one field of study at the university of applied sciences. I used phenomenographic analysis to elucidate the conceptions and collected the data in interviews of personnel (22) who belong to the management of the university of applied sciences. The data for analysing the obstacles faced and the ways of overcoming them during the formation process of the new concept consist of the video-recorded material from ten change laboratory sessions held for the specific field of study at the university of applied sciences. In researching the formation of the concept of the activity, such research and analysis methods are used in which the concept is understood as a material construction, and with the help of which one can work out the formation of the concept during the development process. When the systematic development of the r&d-work was underway, the management of the university of applied sciences held differing views regarding the content, target, factors and organisation of the r&d-activities, as well as regarding the position of dissertations as a part of r&d-activity. Obstacles for developing rd concerned the unclear object and outcomes of the new activity, not having the tools (such as adequate know-how) for the new activity and not having found the necessary solutions for the distribution of work. In addition the rules that quide the activities of the university of applied sciences did not support working according to the new way. To improve r&d-activity, the school’s management defined three development strategies to encourage adequate rd-activity to support working life, regional development and learning. The strategies were based on the expansion of existing methods, such as service activities, dissertation work and the research activities of the teachers. Of the three possible routes, the concept of dissertation in this study was expanded to integrate the services of organisation development and the occupational growth of the students. A group of teachers in the field of social and health studies participated in the development work. The change laboratory method was used as a tool for this work. Analysis of the cognitive trails indicated that, in addition to the cycle of expansive learning activities, microcycles with different purposes can exist. According to Cussins (1992), something already in existence in each microcycle is destabilised, and something else is stabilised to replace it. In this study three microcycles were identified, during which the teachers first destabilised the existing concepts of dissertation work that guided their thinking, and then began to use new concepts to structure their thinking. Secondly, they undermined the existing concepts with material structure that defined their practical work, and developed new practical models to replace them. Thirdly, the problems accumulating in researching and testing the new activities caused the developers to destabilise the r&d-strategies of the university of applied sciences and to define a new conceptual model for r&d-work in the field. During this third cycle, the teachers developed a research arena model, which was a significant expansive innovation. In the cognitive trails developing the new concept for the r&d-activity, the teachers indeed faced the obstacles the management had described as their conceptions. These obstacles manifested themselves as contradictions. During the development process, the nature of the obstacles (i.e. contradictions) changed as the development proceeded. Solving the first and second degree contradictions highlighted the third and fourth degree contradictions. To overcome the obstacles, the teachers had to to articulate the value and motive of the development work throughout the development process. Developing the new concept for r&d-activity required many reconfigurations of practical solutions to overcome the obstacles. Developing the new concept for r&d-activity, both at the level of representations and of new practices, requires universities of applied sciences to adopt new methods in which the actors are partake in construction of new concepts of activity through adequate discussion, analysis and debate. R&d -activity can progress, if instead of implementing partial solutions, the totality of the activities (i.e. the group of partial solutions acting together) will be constructed. The development of the activity system requires many simultaneous changes as well as wide-ranging know-how and discussion related to these changes. What is perhaps most important, however, is that the group of developers mature into a determined collective actor which can engage in many agentive actions. The development of the agency is fundamental to progress.

Sensory auditory processing and intuitive sound detection : an investigation of musical experts and nonexperts

The auditory system can detect occasional changes (deviants) in acoustic regularities without the need for subjects to focus their attention on the sound material. Deviant detection is reflected in the elicitation of the mismatch negativity component (MMN) of the event-related potentials. In the studies presented in this thesis, the MMN is used to investigate the auditory abilities for detecting similarities and regularities in sound streams. To investigate the limits of these processes, professional musicians have been tested in some of the studies. The results show that auditory grouping is already more advanced in musicians than in nonmusicians and that the auditory system of musicians can, unlike that of nonmusicians, detect a numerical regularity of always four tones in a series. These results suggest that sensory auditory processing in musicians is not only a fine tuning of universal abilities, but is also qualitatively more advanced than in nonmusicians. In addition, the relationship between the auditory change-detection function and perception is examined. It is shown that, contrary to the generally accepted view, MMN elicitation does not necessarily correlate with perception. The outcome of the auditory change-detection function can be implicit and the implicit knowledge of the sound structure can, after training, be utilized for behaviorally correct intuitive sound detection. These results illustrate the automatic character of the sensory change detection function.

Cognitive Functioning in Young Adults with Depression, Anxiety Disorders, or Burnout Symptoms : Findings from a Population-based Sample

Background. Evidence of cognitive dysfunction in depressive and anxiety disorders is growing. However, the neuropsychological profile of young adults has received only little systematic investigation, although depressive and anxiety disorders are major public health problems for this age group. Available studies have typically failed to account for psychiatric comorbidity, and samples derived from population-based settings have also seldom been investigated. Burnout-related cognitive functioning has previously been investigated in only few studies, again all using clinical samples and wide age groups. Aims. Based on the information gained by conducting a comprehensive review, studies on cognitive impairment in depressive and anxiety disorders among young adults are rare. The present study examined cognitive functioning in young adults with a history of unipolar depressive or anxiety disorders in comparison to healthy peers, and associations of current burnout symptoms with cognitive functioning, in a population-based setting. The aim was also to determine whether cognitive deficits vary as a function of different disorder characteristics, such as severity, psychiatric comorbidity, age at onset, or the treatments received. Methods. Verbal and visual short-term memory, verbal long-term memory and learning, attention, psychomotor processing speed, verbal intelligence, and executive functioning were measured in a population-based sample of 21-35 year olds. Performance was compared firstly between participants with pure non-psychotic depression (n=68) and healthy peers (n=70), secondly between pure (n=69) and comorbid depression (n=57), and thirdly between participants with anxiety disorders (n=76) and healthy peers (n=71). The diagnostic procedure was based on the SCID interview. Fourthly, the associations of current burnout symptoms, measured with the Maslach Burnout Inventory General Survey, and neuropsychological test performance were investigated among working young adults (n=225). Results. Young adults with depressive or anxiety disorders, with or without psychiatric comorbidity, were not found to have major cognitive impairments when compared to healthy peers. Only mildly compromised verbal learning was found among depressed participants. Pure and comorbid depression groups did not differ in cognitive functioning, either. Among depressed participants, those who had received treatment showed more impaired verbal memory and executive functioning, and earlier onset corresponded with more impaired executive functioning. In anxiety disorders, psychotropic medication and low psychosocial functioning were associated with deficits in executive functioning, psychomotor processing speed, and visual short-term memory. Current burnout symptoms were associated with better performance in verbal working memory and verbal intelligence. However, lower examiner-rated social and occupational functioning was associated with problems in verbal attention, memory, and learning. Conclusions. Depression, anxiety disorders, or burnout symptoms may not be associated with major cognitive deficits among young adults derived from the general population. Even psychiatric comorbidity may not aggravate cognitive functioning in depressive or anxiety disorders among these young adults. However, treatment-seeking in depression was found to be associated with cognitive deficits, suggesting that these deficits relate to increased distress. Additionally, early-onset depression, found to be associated with executive dysfunction, may represent a more severe form of the disorder. In anxiety disorders, those with low symptom-related psychosocial functioning may have cognitive impairment. An association with self-reported burnout symptoms and cognitive deficits was not detected, but individuals with low social and occupational functioning may have impaired cognition.

The Freudian unconscious in the context of the cognitive orientation

For decades psychoanalysis was the discipline studying the unconscious, and other branches of study lacked competence to take a stand on the issues concerning the unconscious. From 1980s onwards intense study of the unconscious has been taken place in the scope of cognitive orientation. Thus, nowadays it is talked about both pyschoanalytic and cognitive unconscious. The aim of this thesis is to integrate psychoanalytic and cognitive views. When the "Freudian" conception of the unconscious is considered, there are four entangled issues: 1) what is the unconscious like, 2) how does the unconsciuos give rise to psychic disorders 3) why and how certain contents are missing from consciousness (repression of contents), 4) the emergence of those contents (becoming conscious of the repressed). The conventional psychoanalytic answer to the first question - and "the cornerstone of psychoanalysis" - is "the unconscious is mental". The issues 2)-4) depend radically on the answer given to the 1): "psychoanalytic" conceptualizations on them rest on the "cornerstone". That ground was challended in study I: it was argued that it has never been clear what does it mean that the unconscious is mental. Thus, it was stated that in the current state of art psychoanalysis should drop out the ephitet "mental" before the term unconscious. That claim creates a pressure to reappraise the convential "psychoanalytic" answers to the other questions, and that reappraisal was the aim of studies II and III. In study II the question 2) is approached in terms of implicit knowledge. Study III focuses on mechanisms, which determine which contents appear in the scope of consciousness, and also cause missing of contents from there (the questions 3) and 4)). In the core of study III there are distinctions concerning the processess occuring in the levels of the brain, consciousness, self-consciousness, and narrative self-consciousness. Studies I-III set "psychoanalytic" topics in the frames of cognitive view. The picture emerging from those studies is not especially useful for a clinican (psychotherapist). Studies IV and V focused that issue. Study IV is a rather serious critique toward neuropsychoanalysis. In it it was claimed that repressive functions of conscious states are in the core of clinical psychoanalysis, and functions in general cannot be reduced to neurophysiological terminology. Thus, the limits of neuropsychoanalysis are more strict than it has been realized: crucial clinical issues remain outside its scope. In study V it was focused on the confusing state of things that although unconscious fantasies do not exist, the idea on them has been an important conceptual tool for clinicans. When put in a larger context, the aim of study V is similar to that of study IV: to determine the relation between psychotherapists' and neuroscientists' terminologies. Studies III, IV and V apply the philosopher Daniel Dennett's model on different levels of explanation.

Cognitive deficits and the Paced Auditory Serial Addition Test performance among patients with multiple sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory disease of the central nervous system, characterized especially by myelin and axon damage. Cognitive impairment in MS is common but difficult to detect without a neuropsychological examination. Valid and reliable methods are needed in clinical practice and research to detect deficits, follow their natural evolution, and verify treatment effects. The Paced Auditory Serial Addition Test (PASAT) is a measure of sustained and divided attention, working memory, and information processing speed, and it is widely used in MS patients neuropsychological evaluation. Additionally, the PASAT is the sole cognitive measure in an assessment tool primarly designed for MS clinical trials, the Multiple Sclerosis Functional Composite (MSFC). The aims of the present study were to determine a) the frequency, characteristics, and evolution of cognitive impairment among relapsing-remitting MS patients, and b) the validity and reliability of the PASAT in measuring cognitive performance in MS patients. The subjects were 45 relapsing-remitting MS patients from Seinäjoki Central Hospital, Department of Neurology and 48 healthy controls. Both groups underwent comprehensive neuropsychological assessments, including the PASAT, twice in a one-year follow-up, and additionally a sample of 10 patients and controls were evaluated with the PASAT in serial assessments five times in one month. The frequency of cognitive dysfunction among relapsing-remitting MS patients in the present study was 42%. Impairments were characterized especially by slowed information processing speed and memory deficits. During the one-year follow-up, the cognitive performance was relatively stable among MS patients on a group level. However, the practice effects in cognitive tests were less pronounced among MS patients than healthy controls. At an individual level the spectrum of MS patients cognitive deficits was wide in regards to their characteristics, severity, and evolution. The PASAT was moderately accurate in detecting MS-associated cognitive impairment, and 69% of patients were correctly classified as cognitively impaired or unimpaired when comprehensive neuropsychological assessment was used as a "gold standard". Self-reported nervousness and poor arithmetical skills seemed to explain misclassifications. MS-related fatigue was objectively demonstrated as fading performance towards the end of the test. Despite the observed practice effect, the reliability of the PASAT was excellent, and it was sensitive to the cognitive decline taking place during the follow-up in a subgroup of patients. The PASAT can be recommended for use in the neuropsychological assessment of MS patients. The test is fairly sensitive, but less specific; consequently, the reasons for low scores have to be carefully identified before interpreting them as clinically significant.

Minimalistinen yhdyssanateoria ja käsitteiden yhdistely

The thesis aims to link the biolinguistic research program and the results of studies in comceptual combination from cognitive psychology. The thesis derives a theory of syntactic structure of noun and adjectival compounds from the Empty Lexicon Hypothesis. Two compound-forming operations are described: root-compounding and word-compounding. The aptness of theory is tested with finnish and greek compounds. From the syntactic theory semantic requirements for conceptual system are derived, especially requirements for handling morphosyntactic features. These requirements are compared to three formidable theories of conceptual combination: relation theory CARIN, Dual-Process theory and C3-theory. The claims of explanatory power of relational distributions of modifier in CARIN-theory ared discarded, as the method for sampling and building relational distributions is not reliable and the algorithmic instantiation of theory does not compute what it claims to compute. From relational theory there still remains results supporting existence of 'easy' relations for certain concepts. Dual-Process theory is found to provide results that cannot in theory be affected by linguistic system, but the basic idea of property compounds is kept. C3-theory is found to be not computationally realistic, but the basic results of diagnosticity and local properties (domains) of conceptual system are solid. The three conceptual combination models are rethought as a problem of finding the shortest route between the two concepts. The new basis for modeling is suggested to be bare conceptual landscape with morphosyntactiic or semantic features working as guidance and structural features of landscape basically unknown, but such as they react to features from linguistic system. Minimalistic principles to conceptual modeling are suggested.

Verkko-oppimateriaalin multimodaalisuus : kohteena YLEn Kansalaisen ABC -verkko-oppimateriaalit

Today information and communication technology allows us to use multimedia more than ever before in e-learning materials. Multimedia though can increase cognitive load in learning process. Because of that it cannot be taken granted what kind of learning materials should be produced. This paper intended to study the diversity of e-learning materials and the factors related cognitive load. The main purpose was to study the multimodality of the multimedia learning materials. The subject of this study is the learning materials on the web site Kansalaisen ABC published by YLE. Learning materials in the web site were approached from three different perspectives. The specific questions were: (1) What kind of form features are used in the representations of the learning material? Are certain form features preferred over others? (2) How do the cognitive load factors take shape in learning materials and between the forms? (3) How does the multimodality phenomenon appear in the learning materials and in what ways are form features and cognitive load factors related to multimodality? In this case study a qualitative approach was used. Analysis of the form features and the cognitive load factors in learning materials were based on content analysis. Form features included the specification of a format, the structure, the interactivity type and the type of learning material. The results showed that the web sites include various representations of both verbal and visual forms. Cognitive load factors were related mostly to visual than verbal material. Material presented according to the principles of cognitive multimedia theory multimedia representations did not cause cognitive overload in the informants. Cognitive load was increased in the case of students needing to split their attention between the multimedia forms in time and place. The results indicated how different individual characteristics are reflected by the cognitive load factors.

Onnistuneen ikääntymisen ymmärrystä rakentamassa : Fysioterapeuttiopiskelijoiden oppiminen kestävää kehitystä edistävän kasvatuksen kehyksessä

The purpose of the present study was to investigate the possibilities and interconnec-tions that exist concerning the relationship between the University of Applied Sci-ences and the Learning by Developing action model (LbD), on the one hand, and education for sustainable development and high-quality learning as a part of profes-sional competence development on the other. The research and learning environment was the Coping at Home research project and its Caring TV project, which provided the context of the Physiotherapy for Elderly People professional study unit. The re-searcher was a teacher and an evaluator of her own students learning. The aims of the study were to monitor and evaluate learning at the individual and group level using tools of high-quality learning − improved concept maps − related to understanding the projects core concept of successful ageing. Conceptions were evaluated through aspects of sustainable development and a conceptual basis of physiotherapy. As edu-cational research this was a multi-method case study design experiment. The three research questions were as follows. 1. What kind of individual conceptions and conceptual structures do students build concerning the concept of successful ageing? How many and what kind of concepts and propositions do they have a) before the study unit, b) after the study unit, c) after the social-knowledge building? 2. What kind of social-knowledge building exists? a) What kind of social learn-ing process exists? b) What kind of socially created concepts, propositions and conceptual structures do the students possess after the project? c) What kind of meaning does the social-knowledge building have at an individual level? 3. How do physiotherapy competences develop according to the results of the first and second research questions? The subjects were 22 female, third-year Bachelor of Physiotherapy students in Laurea University of Applied Sciences in Finland. Individual learning was evaluated in 12 of the 22 students. The data was collected as a part of the learning exercises of the Physiotherapy for Elderly People study unit, with improved concept maps both at individual and group levels. The students were divided into two social-knowledge building groups: the first group had 15 members and second 7 members. Each group created a group-level concept map on the theme of successful ageing. These face-to-face interactions were recorded with CMapTools and videotaped. The data consists of both individually produced concept maps and group-produced concept maps of the two groups and the videotaped material of these processes. The data analysis was carried out at the intersection of various research traditions. Individually produced data was analysed based on content analysis. Group-produced data was analysed based on content analysis and dialogue analysis. The data was also analysed by simple statistical analysis. In the individually produced improved concept maps the students conceptions were comprehensive, and the first concept maps were found to have many concepts unrelated to each other. The conceptual structures were between spoke structures and chain structures. Only a few professional concepts were evident. In the second indi-vidual improved concept maps the conception was more professional than earlier, particulary from the functional point of view. The conceptual structures mostly re-sembled spoke structures. After the second individual concept mapping social map-ping interventions were made in the two groups. After this, multidisciplinary concrete links were established between all concepts in almost all individual concept maps, and the interconnectedness of the concepts in different subject areas was thus understood. The conceptual structures were mainly net structures. The concepts in these individual concept maps were also found to be more professional and concrete than in the previ-ous concept maps of these subjects. In addition, the wider context dependency of the concepts was recognized in many individual concept maps. This implies a conceptual framework for specialists. The social-knowledge building was similar to a social learning process. Both socio-cultural processes and cognitive processes were found to develop students conceptual awareness and the ability to engage in intentional learning. In the knowl-edge-building process two aspects were found: knowledge creation and pedagogical action. The discussion during the concept-mapping process was similar to a shared thinking process. In visualising the process with CMapTools, students easily comple-mented each others thoughts and words, as if mutually telepathic . Synthesizing, supporting, asking and answering, peer teaching and counselling, tutoring, evaluating and arguing took place, and students were very active, self-directed and creative. It took hundreds of conversations before a common understanding could be found. The use of concept mapping in particular was very effective. The concepts in these group-produced concept maps were found to be professional, and values of sustainable development were observed. The results show the importance of developing the contents and objectives of the European Qualification Framework as well as education for sustainable development, especially in terms of the need for knowledge creation, global responsibility and systemic, holistic and critical thinking in order to develop clinical practice. Keywords: education for sustainable development, learning, knowledge building, improved concept map, conceptual structure, competence, successful ageing

Viisi vuotta tiedonrakentamista yhteisö- ja teknologiaelementtien muovautumisen näkökulmasta

The object of this study was to examine the phenomena of a long-term Knowledge Building process. The subject was OECD/ENSI/FI-project's Knowledge Building in Knowledge Forum®3.4 environment from 8.9.2000 to 8.9.2005. Research was based on socio-cognitive and socio-cultural learning approaches and the theoretical background consisted of models of collaborative learning and knowledge processing. These theoretical applications were first structured using metaphors of language and then assembled into five main theoretical motifs. The main motifs were 1) context, 2) inter-subjective, shared area, 3) community's practices and participation, 4) developing expertise and 5) the sequential construction of processes. These themes were assembled in interpreting the results using the Mutual Shaping of Technological and Social Elements by Boczkowski (1999) as a conceptual tool. The social elements of the mutual shaping process were defined as 1) community structure, 2) discourse and 3) the meanings of activity. The technological elements were defined as 1) shared artefacts, 2) features of technology-use and 3) other technological conventions perceived in activity. The five main theoretical motifs were used as the basis for creating the research problems, which were divided into three themes: 1) shared artefacts, themes of Knowledge Building and participant formation, 2) patterns of participation and interaction and 3) the meanings of activity. As methods I used content analysis of the messages, the quantitative profiling of changes in the database, social network analysis, discourse analysis of selected message threads and theme interviews of eleven participants. Based on my study it's possible to say, that a long-term setting of this kind provides a different perspective on Knowledge Building from most of the previous research. The most valuable conclusions from the data are: 1) The centralisation of interaction in this type of setting is a feature that supports the improvement in the quality of action. 2) The participation in a long-term Knowledge Building process seems to support the concious effort on professional development and the expert-identity. 3) The quality of plasticity of the technology-in-use has implication for how the communal features of activity will develop. The agency is seen to initiate processes that in turn open up new possibilities for the quality of action on both the communal and individual levels.

Biophysical Characterization of Oxidized Phospholipids : Implications for Altered Membrane Structure and Function

The present study aims to elucidate the modifications in the structure and functionality of the phospholipid matrix of biological membranes brought about by free radical-mediated oxidative damage of its molecular constituents. To this end, the surface properties of two oxidatively modified phospholipids bearing an aldehyde or carboxyl function at the end of truncated sn-2 acyl chain were studied using a Langmuir balance. The results obtained reveal both oxidized species to have a significant impact on the structural dynamics of phospholipid monolayers, as illustrated by the progressive changes in force-area isotherms with increasing mole fraction of the oxidized lipid component. Moreover, surface potential measurements revealed considerable modifications in the electric properties of oxidized phospholipid containing monolayers during film compression, suggesting a packing state-controlled reorientation of the intramolecular electric dipoles of the lipid headgroups and acyl chains. Based on the above findings, a model describing the conformational state of oxidized phospholipid molecules in biological membranes is proposed, involving the protrusion of the acyl chains bearing the polar functional groups out from the hydrocarbon phase to the surrounding aqueous medium. Oxidative modifications alter profoundly the physicochemical properties of unsaturated phospholipids and are therefore readily anticipated to have important implications for their interactions with membrane-associating molecules. Along these lines, the carboxyl group bearing lipid was observed to bind avidly the peripheral membrane protein cytochrome c. The binding was reversed following increase in ionic strength or addition of polyanionic ATP, thus suggesting it to be driven by electrostatic interactions between cationic residues of the protein and the deprotonated lipid carboxyl exposed to the aqueous phase. The presence of aldehyde function bearing oxidized phospholipid was observed to enhance the intercalation of four antimicrobial peptides into phospholipid monolayers and liposomal bilayers. Partitioning of the peptides to monolayers was markedly attenuated by the aldehyde scavenger methoxyamine, revealing it to be mediated by the carbonyl moiety possibly through efficient hydrogen bonding or, alternatively, formation of covalent adduct in form of a Schiff base between the lipid aldehydes and primary amine groups of the peptide molecules. Lastly, both oxidized phospholipid species were observed to bind with high affinity three small membrane-partitioning therapeutic agents, viz. chlorpromazine, haloperidol, and doxorubicin. In conclusion, the results of studies conducted using biomimetic model systems support the notion that oxidative damage influences the molecular architecture as well as the bulk physicochemical properties of phospholipid membranes. Further, common polar functional groups carried by phospholipids subjected to oxidation were observed to act as molecular binding sites at the lipid-water interface. It is thus plausible that oxidized phospholipid species may elicit cellular level effects by modulating integration of various membrane-embedded and surface-associated proteins and peptides, whose conformational state, oligomerization, and functionality is known to be controlled by highly specific lipid-protein interactions and proper physical state of the membrane environment.

The structure of Norway spruce (Picea abies [L.] Karst.) stems in relation to wood properties of sawn timber

An important challenge in forest industry is to get the appropriate raw material out from the forests to the wood processing industry. Growth and stem reconstruction simulators are therefore increasingly integrated in industrial conversion simulators, for linking the properties of wooden products to the three-dimensional structure of stems and their growing conditions. Static simulators predict the wood properties from stem dimensions at the end of a growth simulation period, whereas in dynamic approaches, the structural components, e.g. branches, are incremented along with the growth processes. The dynamic approach can be applied to stem reconstruction by predicting the three-dimensional stem structure from external tree variables (i.e. age, height) as a result of growth to the current state. In this study, a dynamic growth simulator, PipeQual, and a stem reconstruction simulator, RetroSTEM, are adapted to Norway spruce (Picea abies [L.] Karst.) to predict the three-dimensional structure of stems (tapers, branchiness, wood basic density) over time such that both simulators can be integrated in a sawing simulator. The parameterisation of the PipeQual and RetroSTEM simulators for Norway spruce relied on the theoretically based description of tree structure developing in the growth process and following certain conservative structural regularities while allowing for plasticity in the crown development. The crown expressed both regularity and plasticity in its development, as the vertical foliage density peaked regularly at about 5 m from the stem apex, varying below that with tree age and dominance position (Study I). Conservative stem structure was characterized in terms of (1) the pipe ratios between foliage mass and branch and stem cross-sectional areas at crown base, (2) the allometric relationship between foliage mass and crown length, (3) mean branch length relative to crown length and (4) form coefficients in branches and stem (Study II). The pipe ratio between branch and stem cross-sectional area at crown base, and mean branch length relative to the crown length may differ in trees before and after canopy closure, but the variation should be further analysed in stands of different ages and densities with varying site fertilities and climates. The predictions of the PipeQual and RetroSTEM simulators were evaluated by comparing the simulated values to measured ones (Study III, IV). Both simulators predicted stem taper and branch diameter at the individual tree level with a small bias. RetroSTEM predictions of wood density were accurate. For focusing on even more accurate predictions of stem diameters and branchiness along the stem, both simulators should be further improved by revising the following aspects in the simulators: the relationship between foliage and stem sapwood area in the upper stem, the error source in branch sizes, the crown base development and the height growth models in RetroSTEM. In Study V, the RetroSTEM simulator was integrated in the InnoSIM sawing simulator, and according to the pilot simulations, this turned out to be an efficient tool for readily producing stand scale information about stem sizes and structure when approximating the available assortments of wood products.