Learning histology – dental and medical students' study strategies

PurposeHistology, the science of cells and tissues at the microscopic level, is an integral component of most dental and medical curricula and is often taught using both traditional and novel computer‐based didactic approaches. The purpose of this study was to analyse the strategies used by dental and medical students when studying this very visual and challenging subject.MethodsData were collected from 75 dental and 143 medical students, who had almost identical histology learning resources at their disposal.ResultsWhen compared with their medical counterparts, dental students view histology as a more difficult subject and as less relevant for their future career. Whereas dental students, who are required to attend class unlike medical students, made more use of in‐classroom learning opportunities, they did not take as much advantage of out‐of‐classroom resources. In addition, dental students reported a significantly higher tendency than medical students to work together, rather than to study alone.DiscussionSmall differences in the dental versus the medical learning environment associate with several observed differences in learning strategies that are adopted by dental and medical students.ConclusionsThese differences should be considered when teaching the subject of histology to dental or to medical students.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111121/1/eje12104.pd

Health-related quality of life across all stages of autosomal dominant polycystic kidney disease

Background. A limited number of studies have assessed health related quality of life (HRQoL) in autosomal dominant polycystic kidney disease (ADPKD). Results to date have been conflicting and studies have generally focused on patients with later stages of the disease. This study aimed to assess HRQoL in ADPKD across all stages of the disease, from patients with early chronic kidney disease (CKD) to patients with end-stage renal disease. Methods. A study involving cross-sectional patient-reported outcomes and retrospective clinical data was undertaken April December 2014 in Denmark, Finland, Norway and Sweden. Patients were enrolled into four mutually exclusive stages of the disease: CKD stages 1-3; CKD stages 4-5; transplant recipients; and dialysis patients. Results. Overall HRQoL was generally highest in patients with CKD stages 1-3, followed by transplant recipients, patients with CKD stages 4-5 and patients on dialysis. Progressive disease predominately had an impact on physical health, whereas mental health showed less variation between stages of the disease. A substantial loss in quality of life was observed as patients progressed to CKD stages 4-5. Conclusions. Later stages of ADPKD are associated with reduced physical health. The value of early treatment interventions that can delay progression of the disease should be considered.Peer reviewe

Comparative analysis of NMPC performance for a semi-batch reactor optimisation problem with uncertain variables using state estimators Extended Kalman Filter and Moving Horizon Estimator

Nonlinear model predictive control (NMPC) er en optimaliseringsteknikk hvor hovedmålet er å beregne kontrollhandlinger som forsikrer optimal drift av en pros- ess. Dette gjøres ved å beregne kontrollhandlingsekvenser som sørger for trygg og pålitelig drift av prosessen for fremtiden. Dersom NMPC-en skal beregne disse sekvensene trenger den informasjon om prosessen den skal kontrollere og dette oppgis som regel i form av ordinære differentialligninger og beskrankninger som er påført optimaliseringsproblemet. I praksis er det derimot ikke alltid mulig å tilføre NMPC-en informasjonen den kr- ever, enten fordi tilstandene er umålelige eller usikre. Usikkerhet i en prosess kan skyldes blant annet prosess- og målestøy og dersom NMPC-en ikke tar dette i be- trakning når den løser optimaliseringsproblemet kan dette føre til sub-optimal eller upresis kontroll av prosessen. Dersom informasjon om tilstandene som NMPC-en kontrollerer er utiljengelige benyttes estimerte tilstander istedenfor og disse bereg- nes med hjelp av tilstandmålinger som inkluderer støy. Et prosjektarbeid ble utført forrige semester og hadde som hovedmål å imple- mentere en NMPC på et allerede eksisterende optimaliseringsproblem av en semi- batch reaktor med mål om å maksimalisere produksjon av et stoff, C, ut ifra reak- tantene A og B. I praksis benytter modellen målinger som inkluderer målestøy og som dermed introduserer usikkerhet til NMPC-en, hvilket forble uadressert i prosjektarbeidet. I tillegg er to av tilstandene i reaktoren, konsentrasjonene av A og B, umålelige og av den grunn må tilstandestimatorer benyttes for å adresse nevnt usikkerhet. Hovedmålet for denne masteroppgaven er av den grunn å utføre et sammenligningsstudie mellom tilstandestimatorene, Extended Kalman Filter (EKF) og Moving Horizon Estimator (MHE) og undersøke hvilken av dem som er best egnet for modellen. Dette gjøres ved å undersøke hvilken av dem som resulterer i størst produksjon av C og som bidrar til forutsigbar og stabil drift av prosessen. Ut ifra resultatene fremstår EKF som det mest kosteffektive alternativet grunnet en høyere produksjon av C med kortere CPU tid sammenlignet med MHE. Hva underpresteringen til MHE skyldes er uklart, men hvordan terminalkostnaden, Γk, har blitt estimert kan være en mulig forklaring. Av den grunn oppfordres videre arbeid til forskning innen andre måter å estimere denne variablen på, noe som forhåpentligvis kan utgjøre en positiv forskjell for ytelsen til MHE sammenlignet med EKF.The nonlinear model predictive controll (NMPC) is an optimisation technique which aims to compute control actions that ensures optimal operation of a pro- cess. This is done by calculating a sequence of control actions which purpose is to control predicted behaviour of the system and thereby provide operational sta- bility. In order to perform this, the NMPC requires information of the process, often given in the form as ordinary differential equations (ODE), and the imposed constraints which limit the optimisation problem. However, obtaining information of the process may not be straightforward in prac- tice. For instance, uncertainty caused by external factors in the form of process and measurement noise could complicate this and result in operational instability if this type of random behaviour is not accounted in the NMPC. Another example are when states are simply immeasurable, either because they are economically expensive or physically impossible to measure, which for instance can be the case for a temperature sensor inside a rocket engine. If information about the opti- misation problem is unattainable, the NMPC has to be provided state estimates instead and there are several methodologies to achieve this. This thesis therefore aims to conduct a comparative study between two state esti- mators, Extended Kalman Filter (EKF) and Moving Horizon Estimator (MHE), which aims to provide filtered estimates to the NMPC based off noisy measure- ments of the states. This study is conducted on a semi-batch reactor, where the aim is to produce the product C from reactants A and B, where measurement data of the concentrations are unavailable. Finally, this thesis aims to include noise re- lated uncertainty that had previously not been adressed in the preparatory work. Based off the results, the EKF appeared to outperform the MHE as the most cost effective choice of state estimator for the NMPC as it was able to produce more C than the latter with less CPU time. However, the main cause for the lower performance of the MHE remains somewhat unclear, and further work towards improving the MHE, most notably regarding the choice of method for estimating the arrival cost, is encouraged

Mortgage Loans on Farm Real Estate in Sample Areas in South Dakota

This is a continuation of a study made by Gabriel Lundy, Department of Agricultural Economics, South Dakota State College, on Mortgage Loans on Farm Real Estate in areas consisting of three townships in each of Haakon, Hyde, Clark, Brookings, and Turner counties. The previous studies cover the period 1910-1930. The present study gives the main emphasis on the five year period, 1931 to 1935, pieturing the comparative information from the five sample areas studied. For the purpose of giving a historical sketch, a number of tables have been included which give the conditions in each of the sample areas for the periods of previously studied. The purpose of this study in the sample areas of Haakon, Hyde, Clark, Brookings, and Turner counties is to present a comparative picture of the mortgage situation based on information obtained from samples for 1931 to 1935

Simulation of Rotor-Stator Interactions (RSI's) in a High Head Francis Turbine

As energy demand is growing along with the quest for green energy the operating range for hydropower is being pushed into non-favourable conditions. The unsteady flow regimes at these conditions lead to transient phenomenons like pressure oscillations that can propagate through the whole turbine, threatening the reliability of the turbine. It is therefore important to identify these pressure pulsations to ensure safe operation. This master thesis presents transient simulations of the Francis model turbine at the Waterpower Laboratory at NTNU for eleven different guide vane openings ranging from a 4-degree opening to a 14-degree opening. The software used for the simulations is ANSYS CFX 18.1, applying the SST turbulence model. The primary focus is Rotor-Stator Interactions (RSI's), hence the model has been simplified accordingly, limiting the computational domain to guide vanes, runner and part of the draft tube. The frequency spectrum for pressure fluctuations have been obtained at several monitor points in the domain through Fast Fourier Transformations (FFT) using MATLAB, and then compared to experimental values for validation. The frequencies for RSI's are quite accurately predicted and it is possible to identify the trends for the amplitudes when considering the pressure pulsations in a single point at different guide vane openings. However, comparing different points in the domain at the same guide vane opening does not yield the same trend for the amplitudes for the simulations and the experiments. It is believed that this is due to differences in mesh resolution for the guide vane domain and the runner domain, but further studies need to be conducted to test this hypothesis

Revascularization of an Excisional Wound in Gingiva and Oral Mucosa. A Scanning Electron Microscopic Study Using Corrosion Casts in Rats

The purpose of this study was to examine microvascular regeneration associated with gingival wound healing. A full-thickness piece of gingiva and oral mucosa was excised along the palatal aspect of the right maxillary first and second molars in 20 young Wistar rats. The contralateral side served as unoperated control. After 2, 4, 7, 10 or 20 days of healing, microvascular corrosion casts were produced and examined by scanning electron microscopy. At 2 days, vessels surrounding the wound were dilated and impressions representing sites of leukocyte margination were prominent in the walls of venules. Capillary buds were emerging from venules and capillaries. At 4 days, the vessel buds had lengthened and connected in pairs to produce capillary loops. At 7 days, new vessels extended deeply into the wound space, mainly from the medial side, in a palisade-like pattern. At 10 days, the denuded bone surface was still not completely revascularized and Volkman\u27s canals opening to the wound area were empty. At 20 days, the bone surface was covered by large, irregular vessels which originated mainly from the palatal mucosa. The periodontal ligament was less important in the tissue re-pair process, while the bony vasculature contributed little or not at all to revascularization of the healing gingiva and palatal mucosa

Quantifying the efficiency of hydroxyapatite mineralising peptides

We present a non-destructive analytical calibration tool to allow quantitative assessment of individual calcium phosphates such as hydroxyapatite (HAP) from mixtures including brushite. Many experimental approaches are used to evaluate the mineralising capabilities of biomolecules including peptides. However, it is difficult to quantitatively compare the efficacy of peptides in the promotion of mineralisation when inseparable mixtures of different minerals are produced. To address this challenge, a series of hydroxyapatite and brushite mixtures were produced as a percent/weight (0–100%) from pure components and multiple (N=10) XRD patterns were collected for each mixture. A linear relationship between the ratio of selected peak heights and the molar ratio was found. Using this method, the mineralising capabilities of three known hydroxyapatite binding peptides, CaP(S) STLPIPHEFSRE, CaP(V) VTKHLNQISQSY and CaP(H) SVSVGMKPSPRP, was compared. All three directed mineralisation towards hydroxyapatite in a peptide concentration dependent manner. CaP(V) was most effective at inducing hydroxyapatite formation at higher reagent levels (Ca2+ = 200mM), as also seen with peptide-silk chimeric materials, whereas CaP(S) was most effective when lower concentrations of calcium (20mM) and phosphate were used. The approach can be extended to investigate HAP mineralisation in the presence of any number of mineralisation promoters or inhibitors