Electrospun poly(d/l-lactide-co-l-lactide) hybrid matrix: a novel scaffold material for soft tissue engineering

Electrospinning is a long-known polymer processing technique that has received more interest and attention in recent years due to its versatility and potential use in the field of biomedical research. The fabrication of three-dimensional (3D) electrospun matrices for drug delivery and tissue engineering is of particular interest. In the present study, we identified optimal conditions to generate novel electrospun polymeric scaffolds composed of poly-d/l-lactide and poly-l-lactide in the ratio 50:50. Scanning electron microscopic analyses revealed that the generated poly(d/l-lactide-co-l-lactide) electrospun hybrid microfibers possessed a unique porous high surface area mimicking native extracellular matrix (ECM). To assess cytocompatibility, we isolated dermal fibroblasts from human skin biopsies. After 5 days of in vitro culture, the fibroblasts adhered, migrated and proliferated on the newly created 3D scaffolds. Our data demonstrate the applicability of electrospun poly(d/l-lactide-co-l-lactide) scaffolds to serve as substrates for regenerative medicine applications with special focus on skin tissue engineering

Hissin tasonovien palotestauksen simulointi elementtimenetelmän avulla

Elevator landing doors have to be able to stop fire from spreading from the floors to the elevator shaft during a building fire. To ensure this, the doors are fire tested according to national and international standards to measure their fire resistance. During fire testing, the structural integrity of the door structure is monitored and evaluated. If a fire test is failed, the landing door design has to be modified and the fire test has to be done again, increasing the total cost of the design process. Considerable savings can thus be reached if the testing process is partially simulated. This thesis presents a finite element model for evaluating the structural response of a landing door during fire test using Ansys and LS-Dyna. The door structure is modelled with shell and solid elements. The materials are defined to account for temperature-dependent changes in their properties. Time-dependent thermal boundary conditions are defined and applied on one side of the door panels to simulate the furnace in a fire test. The resulting temperature field is then applied as a load in an explicit structural analysis to determine the door integrity. These results are compared to existing fire test data to verify the FE-model. Additional reinforcement components are then added and the simulation is run again to compare the results between the configurations. The results of the simulations were found to be in qualitative agreement with real life experiences, although replicating the results of the reference test accurately proved challenging. It was found that extra reinforcement components can provide up to 45 % improvement in fire durability. Based on the results, this study concludes that simulation is a promising way to estimate the fire performance of new door designs during the design process. More work is needed in terms of obtaining more accurate experimental data to help develop a more accurate and effective simulation model.Hissin tasonovien on kyettävä estämään tulipalon leviäminen kerroksesta hissikuiluun. Tasonovien suorituskyky varmistetaan testaamalla niiden palonkestävyyttä kansainvälisten standardien mukaisesti palokokeessa. Mikäli ovi ei läpäise palokoetta, ovi on suunniteltava uudelleen ja palokoe on toistettava, mikä kasvattaa tuotekehitysprosessin kustannuksia. Palokokeen osittainen simulointi voi täten johtaa huomattaviin kustannussäästöihin. Tässä työssä esitellään elementtimenetelmään perustuva malli, jolla arvioidaan tasonoven rakenteellista kestävyyttä palokokeen aikana. Malli koostuu kuori- ja 3D-elementeistä ja se ratkaistaan käyttäen Ansys- ja LS-Dyna-ohjelmistoja. Oven materiaaleille määritetään lämpötilariippuvaiset ominaisuudet, ja paloa simuloidaan asettamalla ovipaneeleille ajasta riippuvaiset säteily- ja konvektioreunaehdot, minkä jälkeen syntynyt lämpötilakenttä siirretään eksplisiittisen rakenneanalyysin kuormaksi. Saatuja tuloksia verrataan palokokeesta saatuihin tuloksiin mallin tulosten varmistamiseksi, minkä jälkeen oveen lisätään erilaisia vahvikekomponentteja ja vertaillaan niiden vaikutusta tuloksiin. Simulaation tulokset olivat laadullisesti yhteneväisiä palokokeista saa-tuihin yleisiin kokemuksiin nähden, mutta referenssipalokokeen tulosten tarkka toistaminen osoittautui haastavaksi. Lisävahvikkeet pienensivät oven siirtymiä jopa 45 prosenttia. Tulosten perusteella voidaan sanoa, että simulointi on lupaava metodi ovien palonkestävyyden arviointiin tuotekehitysprosessin aikana. Jatkokehitys on kuitenkin tarpeen tarkemman kokeellisen datan saamiseksi, jotta mallia voitaisiin kehittää tarkemmaksi ja tehokkaammaksi

Neurosensory disturbance after bilateral sagittal split osteotomy

Abstract Neurosensory disturbance is a common complication of bilateral sagittal split osteotomy (BSSO). This study focuses on the evaluation of factors affecting neurosensory disturbance after BSSO. Furthermore, the study focuses on the measurement of neurosensory disturbance with easily available bedside tests, not only on evaluating the state of sensory disturbance at each follow-up, but also on predicting the potential for recovery. Moreover, panoramic radiography, computerized tomography (CT) and conventional spiral tomography are assessed on locating the mandibular canal. The study was carried out involving a total of 50 patients undergoing BSSO for the correction of mandibular deficiency. In addition, 20 voluntary healthy students participated in this study. Questionnaires, a battery of neurosensory tests and preoperative imaging of the mandibular canal were used. A high incidence of neurosensory disturbance of the lower lip and chin was found after BSSO. However, recovery of sensation occurred with increasing frequency during the follow-up, and after one year sensation of the lower lip and chin returned to the presurgical situation in most patients. A prolonged neurosensory disturbance was more frequent in older patients, in large surgical movements of the mandible and in cases where the inferior alveolar nerve was manipulated during surgery. The bedside tests used in this study correlated well with the patients' subjective evaluation of neurosensory disturbance, and the repeatability of these tests was good. Furthermore, the sensibility testing of the mandibular teeth correlated well with the other tests and patient's subjective evaluation. Four days after surgery, sensibility testing of the mandibular teeth was an efficient test alone to predict the recovery from neurosensory disturbance. On radiographic imaging, the risk for neurosensory disturbance after BSSO could not be predicted from the panoramic radiograph. Before BSSO, CT was the best method to visualize the buccolingual location of the mandibular canal. After BSSO, a clinical follow-up using a battery of mechano- and nociceptive tests in the examination of sensation of the lower lip and chin, sensibility testing of the teeth, and subjective evaluation is needed. CT should be a part of treatment planning of the patients with thin rami or severe asymmetries of the mandible

Autotransplantation donor tooth site harvesting using piezosurgery

Abstract Background: The harvesting of a tooth as a candidate for tooth autotransplantation requires that the delicate dental tissues around the tooth be minimally traumatized. This is especially so for the periradicular tissues of the tooth root and the follicular tissues surrounding the crown. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction in the harvesting of teeth for autotransplantation. Methods: A piezosurgical handpiece and its selection of tips were easily adapted to allow the harvesting and delivery of teeth for autotransplantation purposes. Results: Twenty premolar teeth were harvested using a piezosurgical device. The harvested teeth were subsequently successfully autotransplanted. All twenty teeth healed in a satisfactory manner without excessive mobility or ankyloses. Conclusions: Piezosurgery avoids some of the traumatic aspects of harvesting teeth and removing bone which are associated with thermal damage from the use of conventional rotary instruments or saws. Piezosurgery can be adapted to facilitate the predictable harvesting of teeth for autotransplantation purposes