SPMT-tekniikka sillan siirrossa

Tämä insinöörityö tehtiin Savon Kuljetus Oy:lle helpottamaan sivusiirrettävien rautatiesiltojen tarjouslaskentaa. Työn tavoitteena oli tutkia uutta SPMT-tekniikkaa ja saada selkeä kuva SPMT-tekniikan suunnittelusta ja käytöstä rautatiesiltojen siirtämisessä. SPMT-tekniikalla tarkoitetaan valmiiksi rakennetun sillan siirtoa pyörillä kulkevilla laveteilla oikealle paikalleen. Nämä lavetit nostavat sillan ilmaan ja hiljaa kuljettavat sen oikealle kohdalle ja laskevat paikoilleen. Työssä pyrittiin kehittämään SPMT-siirtomenetelmän käyttö- ja toteutusmahdollisuuksia ja sillan siirrosta syntyvien kustannusten teoreettista vähentämistä. Opinnäytetyön teko alkoi sivussa rakennettavan sillan suunnittelusta sekä sillan siirtoon vaadittavien suunnittelutietojen tutkimisesta. Sillan siirron suunnittelussa tärkeintä oli selvittää sillan rakenteisiin sekä perustamisolosuhteisiin vaikuttavat tekijät. Työssä tehtiin katsaus Suonenjoen Casetapaukseen, jossa silta siirrettiin paikoilleen uudella SPMT-tekniikalla. Tapauksessa huomioidaan maaolosuhteet sekä annetaan yleiskuvaus tapahtuneesta. Työssä otetaan myös kantaa SPMT-tekniikan toteutettavuuteen sekä turvallisuuteen. Kustannusten ja tuotannon tehokkuuden vertailu SPMT:n ja tunkkaamisen välillä on hankalaa. Tämä johtuu siitä, että jokainen työkohde on erilainen. Suurimmat erot syntyvät juuri maatöiden osalta sekä kaluston rajoittuneesta saannista Suomessa. Kaikista ongelmista huolimatta urakoitsijalla ja tilaajalla on molemmilla sama tavoite, pyrkiä saamaan silta siirrettyä mahdollisimman nopeasti, edullisesti ja turvallisesti paikoilleen.This project was made for Savon Kuljetus Oy (construction company) to ease their offer calculation in sideways movable railroad bridges. The aim of this study was to examine the new the SPMT-technique and have a clear picture of designing and usage of the SPMT-technique in moving railroad bridges. The SPMT-technique means moving a finished bridge to the right spot with cradles on wheels. These cradles lift up a bridge and slowly move it to the right spot and put it down. The aim in this project was to develop usage and implementation possibilities in the SPMT-technique and to lower the theoretical costs for moving bridge. The project was started by designing the bridge to be built on the side of the track and then the needed design information for moving the bridge was studied. In designing the movable bridge the most important thing was to figure out the factors affecting the bridge structures and foundation conditions. A case study in Suonenjoki where a bridge was moved in to the place with the new SPMT-technique was introduced in the project. In the case attention was paid to the ground conditions and it also gave a general description of procedures. The reliability and the security of the SPMT-technique was evaluated. Comparing costs and the effectivity of production for the SPMT-technique and normal bridge moving techniques is difficult. This occurs because every project is different. It was stated in this project that the biggest differences come from ground work and the limited amount of usable equipment in Finland. As a result of this project it was confirmed, despite of occurring problems, that the contractor and the client both have the same goal, an intention to move the bridge as quickly, cost efficiently and safely as possible to the right spot

Desmosomes in Developing Human Epidermis

Desmosomes play important roles in the cell differentiation and morphogenesis of tissues. Studies on animal models have greatly increased our knowledge on epidermal development while reports on human developing skin are rare due to the difficult accessibility to the samples. Although the morphology of periderm cells and the process how the epidermis develops very much resemble each other, the timetable and the final outcome of a mature human epidermis markedly differ from those of murine skin. Even the genetic basis of the junctional components may have profound differences between the species, which might affect the implementation of the data from animal models in human studies. The aim of this review is to focus on the development of human skin with special emphasis on desmosomes. Desmosomal development is mirrored in perspective with other simultaneous events, such as maturation of adherens, tight and gap junctions, and the basement membrane zone

Sydämen magneettikuvaus: Virhelähteet virtausten vaihekontrastimittauksissa

Phase contrast velocity encoded flow measurement was first introduced 30 years ago and have been subject to constant evolution since. The method has been validated repeatedly to be suitable for numerous clinical applications. It is capable to visualize and quantify dynamic phenomena such as blood flow in any part of the human body without being invasive or using ionizing radiation. Recent publications even suggest that velocity encoded imaging should be used as a gold standard in the flow measurements of great arteries. Despite of numerous possibilities, the method remains underused. However, phase contrast flow imaging carries some challenges that are limiting clinical applicability. First of all, magnetic resonance imaging is expensive and time consuming imaging modality. Currently velocity encoded flow imaging can be seen as a secondary modality which is used if necessary after alternative methods such as ultrasound. Also, phase contrast flow imaging includes numerous physical and physiological error sources affecting the accuracy of flow measurements. The understanding of these error sources is important to be able to estimate the accuracy of obtained results. An overview on these error sources is presented in this work. Essential theoretical basis to understand the physics underlying the error mechanisms are presented and means to minimize the error are addressed. The dimensions of human arteries are varying considerably along the flow track beyond the ventricles. Changing geometrical dimension and individual characteristics of cardiac valves are giving a raise to several spatially alternating flow phenomena such as acceleration artefact and voxel dephasing. In this work a research is presented where optimal measurement plane to quantify stroke volume is studied. The importance of optimal measurement plane is studied in both healthy controls and patients with accelerated flow velocities. In the work it was found that optimal location to measure arterial flow is approximately 2 cm distal from the aortic or pulmonal valve in case of accelerated flow. In controls no such relation was found between the measurement plane and the stroke volume. We are also considering the amount of hardware velocity offset in our measurement system and discussing how it affects to the results.Nopeusherkkään vaihekontrastiin perustuva magneettikuvausmenetelmä on tehokas tapa suurten valtimoiden virtausten tutkimiseen. Menetelmällä on mahdollista määrittää virtauksen nopeus missä tahansa paikassa ja suunnassa ihmiskehossa ilman ionisoivaa säteilyä tai kajoamista kehon sisälle. Nykytutkimuksen valossa nopeusherkkiä vaihekontrastimittauksia pidetään erilaisten sydänsairauksien arviointiperusteena. Menetelmän kiistattomista eduista huolimatta sitä käytetään tällä hetkellä huomattavan vähän. Nopeusherkän vaihekontrastikuvantamisen kliinistä käyttöä rajoittavat haasteet sovellettavuudessa jokapäiväiseen sairaalatyöhön. Magneettikuvaus itsessään on tällä hetkellä suhteellisen kallis tutkimusmodaliteetti ja sitä on pidettävä sydänsairauksien osalta toisen linjan kuvantamisemenetelmänä ultraäänitutkimuksen jälkeen. Itse nopeusherkkään vaihekontrastiin perustuva kuvantaminen on altis useille fysikaaliseen perustaan ja ihmisen fysiologiaan liittyville virhelähteille. Esimerkiksi kiihtyneessä valtimoverenkierrossa syntyvät turbulenssit ja sydämen rytmihäiriöt saattavat aiheuttaa merkittävää virhettä mitattuihin tuloksiin. Tässä työssä on tehty kirjallisuustutkimus, jossa eritellään nopeusherkällä vaihekontrastikuvantamisella saatuihin tuloksiin vaikuttavat virhemekanismit. Lisäksi käydään läpi mekanismien taustojen ymmärtämiseen vaadittava teoria ja esitellään keinoja syntyvän virheen minimoimiseksi. Suurissa valtimoissa kulkevan veren virtauksen luonne on vahvasti paikkariippuvaista. Näin ollen mitattaessa sydämen tunnuslukuja nopeusherkkään vaihekontrastiin perustuvalla menetelmällä on mittaukseen käytettävän kuvatason paikalla merkittävä vaikutus tuloksiin. Kuvatason paikan vaikutusta mitattuun sydämen vasemman ja oikean kammion iskutilavuuteen on selvitetty kokeellisessa tutkimuksessa. Saatujen tulosten mukaan optimaalinen kuvatason paikka sijaitsee noin 2 cm etäisyydellä valtimoläpästä distaalisesti potilailla joilla on kiihtynyt valtimoveren virtaus. Terveillä koehenkilöillä ei kuvatason paikalla havaittu olevan merkittävää vaikutusta mitattuun kammion iskutilavuuteen. Tutkimuksessa käsitellään lisäksi kokeellisessa osassa käytetyn laitteiston aiheuttamaa virhettä tuloksiin

Characterizing geometric distortions of 3D sequences in clinical head MRI

Objective Phantoms are often used to estimate the geometric accuracy in magnetic resonance imaging (MRI). However, the distortions may differ between anatomical and phantom images. This study aimed to investigate the applicability of a phantom-based and a test-subject-based method in evaluating geometric distortion present in clinical head-imaging sequences. Materials and methods We imaged a 3D-printed phantom and test subjects with two MRI scanners using two clinical head-imaging 3D sequences with varying patient-table positions and receiver bandwidths. The geometric distortions were evaluated through nonrigid registrations: the displaced acquisitions were compared against the ideal isocenter positioning, and the varied bandwidth volumes against the volume with the highest bandwidth. The phantom acquisitions were also registered to a computed tomography scan. Results Geometric distortion magnitudes increased with larger table displacements and were in good agreement between the phantom and test-subject acquisitions. The effect of increased distortions with decreasing receiver bandwidth was more prominent for test-subject acquisitions. Conclusion Presented results emphasize the sensitivity of the geometric accuracy to positioning and imaging parameters. Phantom limitations may become an issue with some sequence types, encouraging the use of anatomical images for evaluating the geometric accuracy.Peer reviewe

The effect of estradiol, testosterone, and human chorionic gonadotropin on the proliferation of Schwann cells with NF1 +/− or NF1 −/− genotype derived from human cutaneous neurofibromas

Dermal neurofibromas are the hallmarks of neurofibromatosis type 1 (NF1). Neurofibromas harbor Schwann cells with two different genotypes: Schwann cells which carry the germline mutation and a healthy NF1 allele (NF1 +/−), and a subpopulation of Schwann cells which harbor the so-called second hit leading to inactivation of both NF1 alleles (NF1 −/−). The second hit in the NF1 gene of Schwann cells is considered to be the initial step in the development of neurofibromas. Dermal neurofibromas typically start to grow in puberty, and their number and size increase during pregnancy, indicating hormone responsiveness. This is the first study to address the effect of human chorionic gonadotropin (hCG) on the proliferation of human NF1 +/− and NF1 −/− Schwann cells in vitro. In addition, the effects of estradiol and testosterone were also investigated. The results showed that NF1 −/− Schwann cells were more sensitive to estradiol, testosterone, and human chorionic gonadotropin than NF1 +/− cells. Specifically, the proliferation of NF1 −/− Schwann cells was increased by up to 99, 110, and 170% compared to vehicle control when treated with estradiol, testosterone, and hCG, respectively. Interestingly, no effect of estradiol, testosterone, or hCG on the proliferation of the cells with NF1 +/− genotype was observed. To conclude, the somatic second hit in the NF1 gene sensitizes Schwann cells to sex hormones resulting in a highly increased proliferation. Our results highlight the significance of sex hormones in the regulation of neurofibroma growth.</p

Inter- and intra-scanner variations in four magnetic resonance imaging image quality parameters

Peer reviewe

Pediatric malignancies in neurofibromatosis type 1 : A population-based cohort study

Neurofibromatosis type 1 (NF1) is a cancer predisposition syndrome with an incidence of 1:2,000. Patients with NF1 have an increased cancer risk and mortality, but there are no population-based cohort studies specifically investigating the risk of childhood malignancies. We used the Finnish NF1 cohort to analyze the incidence, risk and prognosis of malignancies in NF1 patientsPeer reviewe

Hierarchical framework to improve individualised exercise prescription in adults : a critical review

Physical activity (PA) guidelines for the general population are designed to mitigate the rise of chronic and debilitating diseases brought by inactivity and sedentariness. Although essential, they are insufficient as rates of cardiovascular, pulmonary, renal, metabolic and other devastating and life-long diseases remain on the rise. This systemic failure supports the need for an improved exercise prescription approach that targets the individual. Significant interindividual variability of cardiorespiratory fitness (CRF) responses to exercise are partly explained by biological and methodological factors, and the modulation of exercise volume and intensity seem to be key in improving prescription guidelines. The use of physiological thresholds, such as lactate, ventilation, as well as critical power, have demonstrated excellent results to improve CRF in those struggling to respond to the current homogenous prescription of exercise. However, assessing physiological thresholds requires laboratory resources and expertise and is incompatible for a general population approach. A case must be made that balances the effectiveness of an exercise programme to improve CRF and accessibility of resources. A population-wide approach of exercise prescription guidelines should include free and accessible self-assessed threshold tools, such as rate of perceived exertion, where the homeostatic perturbation induced by exercise reflects physiological thresholds. The present critical review outlines factors for individuals exercise prescription and proposes a new theoretical hierarchal framework to help shape PA guidelines based on accessibility and effectiveness as part of a personalised exercise prescription that targets the individual.Peer reviewe