Multiple sclerosis and pregnancy: clinical and immunological aspects

Background: Multiple Sclerosis (MS) is an autoimmune disease of the central nervous system that affects most commonly young women in their childbearing age. Previous studies have shown that MS relapse rate usually reduces during pregnancy and increases again after delivery. Patients with MS and their treating physicians are interested to know more about the risks the disease can cause to pregnancy and how pregnancy affects the disease. The reasons for increased relapse rate after delivery are not entirely clear, but loss of pregnancy related immune tolerance and changes in the hormonal status at the time of delivery seem to be of relevance. Aims and methods: The aims of this study were to follow the natural course of MS during and after pregnancy, evaluate pregnancy related risks among MS patients, follow the inflammatory response of MS patients during and after pregnancy and clarify the risk of relevant co-morbidities known to affect other autoimmune diseases after pregnancy and compare these results to healthy controls. This study was a part of a prospective nation-wide follow-up study of 60 Finnish MS patients. All eligible MS patients were enrolled in the study during the years 2003-2005. A prospective followup continued from early pregnancy until six months postpartum. MS relapses, EDSS scores and obstetric details were recorded. Blood samples were obtained from the patients at early, middle, and late pregnancy, after delivery and one month, three months and six months postpartum. Results: MS patients were no more likely to experience pregnancy or delivery complications than the Finnish mothers in general. The need of instrumental assistance, however, was higher among mothers with MS. Disease activity followed the course seen in previous studies. The majority of mothers (90.2%) breastfed their babies. Contrary to previous results, breastfeeding did not protect MS patients from disease worsening after delivery in present study. Mothers with active pre-pregnancy disease chose to breastfeed less frequently and started medication instead. MS patients presented with higher prevalence of elevated thyroid autoantibodies postpartum than healthy controls, but the rate of thyroid hormonal dysfunction was similar as that of healthy controls. The mode of delivery nor the higher rate of tissue damage assessed with C-reactive protein concentration were not predictive of postpartum relapses. The prevalence of gestational diabetes was slightly higher among mothers with MS compared to Finnish mothers in general, but postpartum depression was observed in similar rates. MS patients presented with significantly lower serum concentrations of vitamin D during pregnancy and postpartum than healthy controls. Conclusions: Childbearing can be regarded as safe for mothers with MS as it is for healthy mothers in general. Breastfeeding can be recommended, but it should be done only after careful evaluation of the individual risk for postpartum disease activation. Considering MS patients tend to develop thyroid antibody positivity after delivery more often than healthy controls and that certain treatments can predispose MS patients to thyroid hormonal dysfunction, we recommend MS mothers to be screened for thyroid abnormalities during pregnancy and after delivery. Increased risk for gestational diabetes should be kept in mind when following MS mothers and glucose tolerance test in early pregnancy should be considered. Adequate vitamin D supplementation is essential for MS mothers also during pregnancy and postpartum period.

Lipeäkierron kemiallisesti parhaat käytännöt

Diplomityön tavoitteena oli kartoittaa kemiallisesti parhaita käytäntöjä sellutehtaiden kemikaalien talteenottoprosessissa. Kirjallisuudesta ei löytynyt lipeäkiertoon liittyvää kemiallista tietoutta. Laiteteknisten ratkaisujen kautta yritettiin saada selville parhaat käytännöt. Teoriaosassa on myös käsitelty lipeäkierrossa esiintyvien vierasaineiden lähteitä, rikastumista ja poistumista prosessista. Työ tehtiin Stora Enson Suomessa sijaitseville tehtaille. Kokeellisessa osassa on suoritettu tehtailta saadun materiaalin perusteella tunnuslukujen laskentaa sekä PCA-analyysin teko. Työssä tarkastelualueena on lipeäkierto liuottajasta meesauuniin. Kaukopäässä on käytössä lipeäkierrossa kaksi lipeälinjaa ja muilla tehtailla vain yksi. Saatujen tunnuslukujen perusteella tehtaille on annettu pisteitä nollasta viiteen. Viisi pistettä on saanut parhaan arvon saanut tehdas ja nolla pistettä kaukana parhaasta arvosta olevat. Tunnuslukuja on valittu 14 ja edellä esitetyllä tavalla pisteytettynä on parhaaksi tehtaaksi saatu Kaukopään 1-lipeälinja ja huonoin on Kemijärvi. Huomioitavaa on Kaukopään 2-lipeälinjan sijoittuminen vasta neljänneksi, vaikka lipeälinjoilla on valkolipeän ja meesan käsittelyssä yhteiset syöttösäiliöt. PCA-analyysin perusteella havaittiin, että kuukausikeskiarvoja käytettäessä tulokset tasoittuvat verrattuna päiväarvoilla tehtyyn analyysiin. Analyysi osoittaa, että tehtailla lipeäkierto ei ole täysin hallinnassa. Tämä ilmenee suurina objektien liikkeinä kuvissa. Päiväarvoilla analyysi tehtiin vain Oulun tehtaalle. Tarkastelussa valittiin kuukauden mittainen ajanjakso niin hyvää kuin huonoakin jaksoa. Mallien selitysasteista voidaan nähdä eroja hyvän ja huonon jakson välillä. Tämä ilmenee niin, että hyvän jakson mallin selitysaste on korkeampi kuin huonon jakson. Objektien sijoittuminen kuvissa on myös erilainen. Hyvän jakson aikana objektit ovat pieninä ryhminä, kun huonon jakson objektit ovat hajonneet yksittäisiksi arvoiksi ja päivien väliset erot ovat suuret.

Hankintastrategian muutoksen vaikutus käyttöpääoman sitoutumiseen: case muodin vähittäiskauppa

Tutkimuksen päätavoitteena on selvittää hankintastrategian muutoksen vaikutusta käyttöpääoman sitoutumiseen. Tutkimus on kvalitatiivinen case-tutkimus. Siinä tutkitaan kohdeyrityksen nuorisomuotimyymälöiden käyttöpääoman kehitystä suhteessa liikevaihtoon viiden vuoden aikasarjalla. Tutkimuksen tiedot ovat kerätty POS-järjestelmästä kuukauden tarkkuudella. Tutkimuksessa seurataan käyttöpääoman trendin lisäksi sesonkivaihteluja. Tutkimusyrityksen uudessa hankintastrategiassa lisättiin sesongin aikaisia express- ja täydennysostojen osuutta. Toimintatavan muutos johti ennakko-ostojen vähenemiseen, mikä puolestaan lyhensi ostojen ja myyntisesongin välistä keskimääräistä aikaa. Lyhyemmät ennakkoajat vähentävät ennustusvirhettä, mikä parantaa varaston hallittavuutta. Parempi ennustettavuus vähentää varmuusvarastojen tarvetta ja joustavampi materiaalivirta tasaa varastonhuippuja. Molemmat tekijät vähentävät myymälöiden käyttöpääoman tarvetta. Tutkimuksen johtopäätöksenä todetaan, että nopeampi toimitusketju vähentää käyttöpääoman tarvetta kohdeyrityksessä. Johtopäätös on yhdenmukainen tutkimuksen teoreettisen viitekehyksen kanssa.

Toimintolaskentamallin luominen kiinteistönhuoltoon

Toimintolaskennasta on tehty runsaasti tutkimuksia suuriin teollisuusyrityksiin, mutta pienille palveluyrityksille tehtyjä toimintolaskennan julkaistuja tutkimuksia on vähän. Tämän tutkimuksen tavoitteena oli tutkia toimintolaskennan soveltuvuutta pienen kiinteistönhuoltoyrityksen kustannuslaskentaan sekä rakentaa alustava toimintolaskentaan pohjautuva asiakas-kustannusten laskentamalli ja testata luotua mallia työaikaseurannan avulla. Tutkimuksen teoriaosassa on perehdytty toimintolaskennan kehitysvaiheisiin ja nykytilaan sekä kuvattu toimintolaskentaprosessin eteneminen käyttöönoton valmistelusta aina laskentatietojen hyväksikäyttöön saakka. Tutkimuksen empiriaosuus etenee edellä mainittuun teoriaan pohjautuen. Teoria- ja empiriaosuuden perusteella voidaan todeta, että kuukausi ei ole riittävän pitkä aika kattavaan seurantaan kiinteistönhuollon toiminnoista, koska vuodenaikojen vaihtelu aiheuttaa suuria muutoksia tehtäviin toimintoihin. Rakennetun laskentamallin ja toteutetun seurannan tulosten perusteella voidaan siitä huolimatta todeta, että toimintolaskentaan pohjautuva kustannusten laskentamalli tuottaa lisäarvoa kiinteistönhuollon asiakaskustannusten määrittelyssä.

Survival and Quality of Life among Patients with Severe Lower Extremity Peripheral Arterial Disease

Lower extremity peripheral arterial disease (PAD) is associated with decreased functional status, diminished quality of life (QoL), amputation, myocardial infarction, stroke, and death. Nevertheless, public awareness of PAD as a morbid and mortal disease is low. The aim of this study was to assess the incidence of major lower extremity amputation due to PAD, the extent of reamputations, and survival after major lower extremity amputation (LEA) in a population based PAD patient cohort. Furthermore, the aim was to assess the functional capacity in patients with LEA, and the QoL after lower extremity revascularization and major amputation. All 210 amputees due to PAD in 1998–2002 and all 519 revascularized patients in 1998–2003 were explored. 59 amputees alive in 2004 were interviewed using a structured questionnaire of QoL. Two of each amputee age-, gender- and domicile-matched controls filled in and returned postal self-administered QoL questionnaire as well as 231 revascularized PAD patients (the amount of these patients who engaged themselves to the study), and one control person for each patient completed postal self-administered QoL questionnaire. The incidence rate of major LEA was 24.1/100 000 person-years and it was considerably high during the years studied. The one-month mortality rate was 21%, 52% at one-year, and the overall mortality rate was 80%. When comparing the one-year mortality risk of amputees, LEAs were associated with a 7.4-fold annual mortality risk compared with the reference population in Turku. Twenty-two patients (10%) had ipsilateral transversions from BK to AK amputation. Fifty patients (24%) ended up with a contralateral major LEA within two to four amputation operations. Three bilateral amputations were performed at the first major LEA operation. Of the 51 survivors returning home after their first major LEA, 36 (71%) received a prosthesis; (16/36, 44%) and were able to walk both in- and outdoors. Of the 68 patients who were discharged to institutional care, three (4%) had a prosthesis one year after LEA. Both amputees and revascularized patients had poor physical functioning and significantly more depressive symptoms than their controls. Depressive symptoms were more common in the institutionalized amputees than the home-dwelling amputees. The surviving amputees and their controls had similar life satisfaction. The amputees felt themselves satisfied and contented, whether or not they lived in long-term care or at home. PAD patients who had undergone revascularizations had poorer QoL than their controls. The revascularized patients’ responses on their perceived physical functioning gave an impression that these patients are in a declining life cycle and that revascularizations, even when successful, may not be sufficient to improve the overall function. It is possible that addressing rehabilitation issues earlier in the care may produce a more positive functional outcome. Depressive symptoms should be recognized and thoroughly considered at the same time the patients are recovering from their revascularization operation. Also primary care should develop proper follow-up, and community organizations should have exercise groups for those who are able to return home, since they very often live alone. In rehabilitation programs we should consider not only physical disability assessment but also QoL.

Identification and characterization of new genes and pathways regulating spermatogonial cell fate

Spermatogenesis, i.e sperm production in the seminiferous tubules of the testis, is a complex process that takes over one month to complete. Life-long ability of sperm production ultimately lies in a small population of undifferentiated cells, called spermatogonial stem cells (SSCs). These cells give rise to differentiating spermatogonia, which are committed to mature into spermatozoa. SSCs represent a heterogeneous population of cells and many aspects of their basic biology are still unknown. Understanding the mechanisms behind the cell fate decision of these cells is important to gain more insights into the causes of infertility and testis cancer. In addition, an interesting new aspect is the use of testis-derived stem cells in regenerative medicine. Our data demonstrated that adult mouse testis houses a population of Nanog-expressing spermatogonia. Based on mRNA and protein analysis these cells are enriched in stage XII of the mouse seminiferous epithelial cycle. The cells derived from this stage have the highest capacity to give rise to ES cell-like cells which express Oct4 and Nanog. These cells are under tight non- GDNF regulation but their fate can be dictated by activating p21 signalling. Comparative studies suggested that these cells are regulated like ES cells. Taken together these data imply that pluripotent cells are present in the adult mammalian testis. CIP2A (cancerous inhibitor of PP2A) has been associated with tumour aggressiveness and poor prognosis. In the testis it is expressed by the descendants of stem cells, i.e. the spermatogonial progenitor cells. Our data suggest that CIP2A acts upstream of PLZF and is needed for quantitatively normal spermatogenesis. Classification of CIP2A as a cancer/testis gene makes it an attractive target for cancer therapy. Study on the CIP2A deficient mouse model demonstrates that systemic inhibition of CIP2A does not severely interfere with growth and development or tissue or organ function, except for the spermatogenic output. These data demonstrate that CIP2A is required for quantitatively normal spermatogenesis. Hedgehog (Hh) signalling is involved in the development and maintenance of many different tissues and organs. According to our data, Hh signalling is active at many different levels during rat spermatogenesis: in spermatogonia, spermatocytes and late elongating spermatids. Localization of Suppressor of Fused (SuFu), the negative regulator of the pathway, specifically in early elongating spermatids suggests that Hh signalling needs to be shut down in these cells. Introduction of Hh signalling inhibitor resulted in an increase in germ cell apoptosis. Follicle-stimulating hormone (FSH) and inhibition of receptor tyrosine kinases resulted in down-regulation of Hh signalling. These data show that Hh signalling is under endocrine and paracrine control and it promotes germ cell survival.

Talviaikainen happitilanne eräissä Pohjois-Savon järvissä vuosina 1997-2008

Pohjois-Savossa seurattiin talviaikaista happitilannetta vuosina 1997-2008. Seurannan kohteena oli neljä pienehköä järveä (Iso-Valkeinen, Kevätön, Kolmisoppi ja Vehmasjärvi), jotka ovat erityyppisiä syvyydeltään, rehevyystasoltaan ja humuspitoisuudeltaan. Näiden esimerkkijärvien oli tarkoitus antaa yleisemminkin viitteitä happitilanteen kehityksestä talven aikana. Alkutalven tulosten perusteella annettiin vuosittain tiedote, jossa arvioitiin happikatojen mahdollisuutta kevättalven kuluessa. Yleisöllä oli myös mahdollisuus seurata happi- ja lämpötilatuloksia Pohjois-Savon ympäristökeskuksen verkkopalvelun kautta. Hapenkulutusnopeus oli rehevimmässä seurantajärvessä kaksinkertainen verrattuna karumpiin ja syvyyden myötä ero vain korostui. Pohjanläheisessä vesikerroksessa 1 mg/l:n happipitoisuus kului karuissa järvissä noin kahdessa viikossa ja rehevässä noin kolmessa päivässä. Vuosien välinen vaihtelu oli kuitenkin hyvin suurta. Vaihtelu oli suurta myös karuissa järvissä. Veden jäätymisajankohdalla ja veden lämpötilalla on merkittävä vaikutus siihen, millainen kevättalven happitilanteesta muodostui. Seurantajärvien aineiston perusteella voidaan karkeasti arvioida, että kuukauden viivästyminen jäätymisessä tai vesipatsaan viilentyminen ennen jäätymistä asteen verran kylmemmäksi merkitsevät noin kolmanneksen korkeampaa happipitoisuutta kevättalvella. Vesipatsaan happitilanteen heikentymisen sekä ravinne- ja rautapitoisuuksien välillä todettiin vahvat yhteydet. Kaikkien järvien aineistossa happitilanteen heikkeneminen johti voimakkaimmin alusveden ammoniumtyppi-, kokonaisfosfori- ja rautapitoisuuksien kasvuun. Pitoisuusmuutokset olivat talven aikana suurimmat rehevimmässä kohdejärvessä, Kevättömässä, jossa kokonaisfosforipitoisuudet keskimäärin kymmenkertaistuivat, fosfaattifosforipitoisuudet kasvoivat keskimäärin 20-kertaisiksi ja rautapitoisuudet yli seitsenkertaisiksi.

Determinants of credit risk in secured loans – Evidence from the auto loan industry

The purpose of this study is to examine attributes which have explanation power to the probability of default or serious overdue in secured auto loans. Another goal is to find out differences between defaulted loans and loans which have had payment difficulties but survived without defaulting. 19 independent variables used in this study reflect information available at the time of credit decision. These variables were tested with logistic regression and backward elimination procedure. The data includes 8931 auto loans from a Finnish finance company. 1118 of the contracts were taken by company customers and 7813 by private customers. 130 of the loans defaulted and 584 had serious payment problems but did not default. The maturities of those loans were from one month to 60 months and they have ended during year 2011. The LTV (loan-to-value) variable was ranked as the most significant explainer because of its strong positive relationship with probability of payment difficulties. Another important explainer in this study was the credit rating variable which got a negative relationship with payment problems. Also maturity and car age performed well having both a positive relationship with the probability of payment problems. When compared default and serious overdue situations, the most significant differences were found in the roles of LTV, Maturity and Gender variables.

Idiosyncratic volatility around information release date

Several papers document idiosyncratic volatility is time-varying and many attempts have been made to reveal whether idiosyncratic risk is priced. This research studies behavior of idiosyncratic volatility around information release dates and also its relation with return after public announcement. The results indicate that when a company discloses specific information to the market, firm’s specific volatility level shifts and short-horizon event-induced volatility vary significantly however, the category to which the announcement belongs is not important in magnitude of change. This event-induced volatility is not small in size and should not be downplayed in event studies. Moreover, this study shows stocks with higher contemporaneous realized idiosyncratic volatility earn lower return after public announcement consistent with “divergence of opinion hypothesis”. While no significant relation is found between EGARCH estimated idiosyncratic volatility and return and also between one-month lagged idiosyncratic volatility and return presumably due to significant jump around public announcement both may provide some signals regarding future idiosyncratic volatility through their correlations with contemporaneous realized idiosyncratic volatility. Finally, the study show that positive relation between return and idiosyncratic volatility based on under-diversification is inadequate to explain all different scenarios and this negative relation after public announcement may provide a useful trading rule.

Indoor air quality at a waste incineration plant in Finland

Waste has been incinerated for energy utilization for more than a hundred years, but the harmful emissions emitted from the incineration plants did not begin to cause concern until the 1980s. Many plants were shutdown and the waste incineration plant in Kyläsaari Helsinki was one of them. In later years, new landfill regulations have increased the interest in waste incineration. During the last year, four new plants were taken into operation in Finland, Westenergy in Vaasa among them. The presence of dust has been observed indoors at Westenergy waste incineration plant. Dust is defined as particles with a diameter above 10 μm, while fine particles have a diameter smaller than 2.5 μm, ultrafine under 0.1 μm and nanoparticles under 0.05 μm. In recent years, the focus of particle health research has been changed to investigate smaller particles. Ultrafine particles have been found to be more detrimental to health than larger particles. Limit values regulating the concentrations of ultrafine particles have not been determined yet. The objective of this thesis was to investigate dust and particles present inside the Westenergy waste incineration facility. The task was to investigate the potential pollutant sources and to give recommendations of how to minimize the presence of dust and particles in the power plant. The total particle number concentrations and size distributions where measured at 15 points inside the plant with an Engine Exhaust Particle Sizer (EEPS) Spectrometer. The measured particles were mainly in the ultrafine size range. Dust was only visually investigated, since the main purpose was to follow the dust accumulation. The measurement points inside the incineration plant were chosen according to investigate exposure to visitors and workers. At some points probable leakage of emissions were investigated. The measurements were carried out during approximately one month in March–April 2013. The results of the measurements showed that elevated levels of dust and particles are present in the indoor air at the waste incineration plant. The cleanest air was found in the control room, warehouse and office. The most polluted air was near the sources that were investigated due to possible leakage and in the bottom ash hall. However, the concentrations were near measured background concentrations in European cities and no leakage could be detected. The high concentrations were assumed to be a result of a lot of dust and particles present on surfaces that had not been cleaned in a while. The main source of the dust and particles present inside the waste incineration plant was thought to be particles and dust from the outside air. Other activities in the area around the waste incineration facility are ground work activities, stone crushing and traffic, which probably are sources of particle formation. Filtration of the outside air prior entering the facility would probably save personnel and visitors from nuisance and save in cleaning and maintenance costs.

The Use of Nervous System Drugs and the Risk of Fractures in Old Adults

Hermostoon vaikuttavien lääkkeiden käyttö on yleistä iäkkäässä väestössä. Erityisen yleistä käyttö on pitkäaikaisessa laitoshoidossa asuvilla iäkkäillä. Hermostoon vaikuttavien lääkkeiden haittavaikutuksia on tutkittu paljon, ja useat hermostoon vaikuttavat lääkeaineryhmät on tunnistettu murtumien riskitekijöiksi. Aikaisemmin ei ole kuitenkaan tutkittu usean hermostoon vaikuttavan lääkkeen yhteiskäytön yhteyksiä murtuman riskiin 65 vuotta täyttäneillä. Väitöskirjatutkimuksessa havaittiin, että usean hermostoon vaikuttavan lääkeaineen yhtäaikainen käyttö oli hyvin yleistä Porin kaupunginsairaalan viidellä pitkäaikaisen laitoshoidon osastolla (n = 154) vuosien 2004 ja 2005 vaihteessa. Kolmasosa tutkituista käytti säännöllisesti kolmea tai useampaa hermostoon vaikuttavaa lääkettä samanaikaisesti. Kun huomioitiin myös tarvittaessa otettavat lääkkeet, vastaava luku oli 53 %. Tutkimuksessa havaittiin myös viitteitä lääkkeiden epäasianmukaisesta käytöstä, kun potilaiden käyttämiä lääkkeitä verrattiin heidän kognitiiviseen ja fyysiseen suorituskyynsä sekä asetettuihin diagnooseihin. Liedon kunnassa 1990-luvulla toteutettuun väestöpohjaiseen Liedon Iäkkäät -seurantatutkimukseen osallistui 1177 lietolaista 65 vuotta täyttänyttä. Lääkitystietoja sekä seuranta-aikana tapahtuneita murtumia analysoimalla havaittiin, että kahden tai useamman bentsodiatsepiinin sekä kahden tai useamman psykoosilääkkeen käyttö oli yhteydessä murtuman riskiin 65 vuotta täyttäneillä miehillä. Opioidin ja psykoosilääkkeen yhteiskäyttö sekä opioidin ja bentsodiatsepiinin yhteiskäyttö oli yhteydessä iäkkäiden miesten murtuman riskiin. Naisilla vastaavia tilastollisesti merkitseviä yhteyksiä ei havaittu. Väitöskirjatutkimuksen uusin osa-aineisto perustui Porissa vuosina 2009–2010 toteutetun Satauni-tutkimuksen aineistoon. Tutkimuksessa osoitettiin 89 potilaan aineistossa, että hallittu, yhden kuukauden aikana lääkärin ja hoitajan tuella toteutettu bentsodiatsepiinivieroitus paransi merkitsevästi 55 vuotta täyttäneiden naisten käden puristusvoimaa kuuden kuukauden seuranta-aikana. Vastaavaa yhteyttä ei havaittu miehillä. Bentsodiatsepiinivieroituksella ei ollut yhteyttä osallistujien tasapainotestin tulosten paranemiseen kuuden kuukauden seurantaaikana. Murtumilla on vakavia seurauksia sekä yksilötasolla että yhteiskunnallisesti iäkkäässä väestössä. Murtumien ehkäisy on hyvin tärkeää. Siinä tulee kiinnittää huomiota potilaan käyttämään lääkitykseen ja arvioida erityisesti usean hermostoon vaikuttavan lääkkeen yhteiskäytön tarpeellisuutta.

Vascular Healing after Coronary Stenting Evaluated by Optical Coherence Tomography

Optical coherence tomography (OCT) is a novel intracoronary imaging application for the assessment of native lesions and coronary stents. The purpose of this thesis was to evaluate the safety and feasibility of frequency-domain OCT (FD-OCT) based on experiences of the Satakunta Central Hospital (I). Early vascular healing was evaluated after implantation of endothelial progenitor cell capturing (II) and bio-active titanium-nitride-oxide coated stents (III) in two studies, each with 20 patients. Vascular healing was also compared after implantation of bio-active and everolimus-eluting stents on 28 patients after 9-month follow-up (IV). Long-term vascular healing of bio-active and paclitaxel-eluting stents was assessed in the last study with 18 patients (V). The results indicate that FD-OCT is safe and feasible (I). Both bio-active and endothelial progenitor cell capturing stents showed near-complete endothelialisation after one-month follow-up, which is desirable when prolonged dual anti-platelet therapy needs to be avoided after stenting (II and III). Endothelialisation of bio-active stents showed a predictable pattern at mid-term and long-term follow up (IV and V). Endothelialisation of everolimus-eluting stents was not complete at 9 months follow-up, which may suggest that interruption of dual antiplatelet therapy at this time point may not be safe (IV). Finally, delayed vascular healing may be present in patients treated with paclitaxel-eluting stents as long as 4 years from implantation, which reinforces the previously raised concerns on the long-term safety of this device (V).

Nursing students and older people nursing. Towards a future career

The purpose of this two-phased study is to examine the interest of nursing students in choosing a career in older people nursing. First, the scoping phase explores the different premises for choosing older people nursing as a career. Second, the evaluation phase investigates the outcomes of the developed educational intervention involving older people as promoters of choosing a career in older people nursing, factors related to these outcomes, and experiences with educational intervention. The ultimate goal is to encourage more nursing students to choose older people nursing as their career. The scoping phase applies an exploratory design and centres around a descriptive, cross-sectional survey, documentary research and a scoping literature review. The information sources for this phase include 183 nursing students, 101 newspaper articles and 66 research articles. The evaluation phase applies a quasi-experimental design and a pre-post-test design with a non-equivalent comparison group and a post-intervention survey. The information sources for this phase include 87 nursing students and 43 older people. In both phases, statistical and narrative methods are applied in the data analysis. Nursing students neutrally regarded the idea of a career in older people nursing. The most consistent factors related to the nursing students’ career plans in older people nursing were found to be nursing work experience and various educational preparations in the field. Nursing students in the intervention group (n=40) were more interested in older people nursing and had more positive attitudes towards older people than did students in the comparison group (n=36). However, in both groups, the interest that students had at the baseline was associated with the interest at the one-month follow-up. There were no significant differences between the groups in terms of the students’ knowledge levels about ageing. The nursing students and older people alike highly appreciated participating in the educational intervention. It seems possible to positively impact nursing students and their choices to pursue careers in older people nursing, at least in the short-term. The involvement of older people as promoters of this career choice provides one encouraging alternative for impacting students’ career choices, but additional research is needed.

Performance Degradation Modelling and Techno-Economic Analysis of Lithium-Ion Battery Energy Storage Systems

Transmission system operators and distribution system operators are experiencing new challenges in terms of reliability, power quality, and cost efficiency. Although the potential of energy storages to face those challenges is recognized, the economic implications are still obscure, which introduce the risk into the business models. This thesis aims to investigate the technical and economic value indicators of lithium-ion battery energy storage systems (BESS) in grid-scale applications. In order to do that, a comprehensive performance lithium-ion BESS model with degradation effects estimation is developed. The model development process implies literature review on lifetime modelling, use, and modification of previous study progress, building the additional system parts and integrating it into a complete tool. The constructed model is capable of describing the dynamic behavior of the BESS voltage, state of charge, temperature and capacity loss. Five control strategies for BESS unit providing primary frequency regulation are implemented, in addition to the model. The questions related to BESS dimensioning and the end of life (EoL) criterion are addressed. Simulations are performed with one-month real frequency data acquired from Fingrid. The lifetime and cost-benefit analysis of the simulation results allow to compare and determine the preferable control strategy. Finally, the study performs the sensitivity analysis of economic profitability with variable size, EoL and system price. The research reports that BESS can be profitable in certain cases and presents the recommendations.