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Coming dissertations at Uppsala university

  • Late Miocene to Pliocene orbital and climatic forcing on marine productivity Author: Boris-Theofanis Karatsolis Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-482527 Publication date: 2022-09-30 13:52

    The late Miocene to Pliocene was a geological time interval of global cooling, albeit in a warmer-than-present world, which is commonly used as a past analogue for future anthropogenic climate change. The investigation of marine sediments recovered by the International Ocean Discovery Program (IODP) sheds light on different paleoclimatic, paleoceanographic and paleobiological characteristics of this period. The NW Australian shelf represents an interesting area for such investigation, because it is strategically positioned near the only remaining equatorial warm-water valve on Earth. In Chapter I and Chapter II, focus is given on calcareous nannofossil time-series data and records of the element potassium (K), which is mainly delivered by rivers to the shelf, at IODP Sites U1463 and U1464. Results demonstrate that humid conditions were probably prevailing earlier than previously thought (at least since ~6 Ma), but that regional tectonics (basin subsidence) has complicated the identification of the exact onset. In addition, nannofossil assemblages data and paleotemperature gradients between the shelfal area and the eastern Indian Ocean reveal a shift in oceanographic and climatic regime that occurred between 5.4-5.2 Ma, as a likely result of an overall long-term increase in seasonality. Finally, an interval of decreasing nannofossil accumulation rates (fluxes) and a distinct change in the dominant nannoplankton species occurred between 4.6-4.4 Ma and is hypothesized to be part of broader changes in ocean nutrient availability. 

    This hypothesis is further explored in Chapter III and Chapter IV through the investigation of a well-established period of globally elevated biogenic sedimentation (and related marine export productivity) known as the late Miocene to early Pliocene biogenic bloom. In Chapter III, age model accuracy and sample resolution of previously published biogenic sediment accumulation rate records are evaluated. The compilation of multiple records shows that an abrupt reduction in ocean paleoproductivity occurred between 4.6-4.4 Ma at (sub)tropical latitudes. This event coincided with a rather unique configuration of the Earth’s orbit, which could have led to a weakened Asian monsoon activity and therefore reduced river runoff and nutrient supply to the ocean. Chapter IV focuses on the comparison between the calcareous nannofossil assemblages at the NW Australian shelf sites and ODP Site 1264 in the South Atlantic Ocean, across the termination of the biogenic bloom. Although the overall decrease in paleoproductivity occurred around the same time, the shift in species dominance across the end of the biogenic bloom, as shown in the tropical Indian Ocean, is not observed at ODP Site 1264. 

  • Internet-based treatment for vulvodynia Author: Andrea Hess Engström Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-482806 Publication date: 2022-09-29 12:53

    Localized provoked vulvodynia is the most common cause of sexual pain and most often affects women between 20 and 30 years old. The etiology of provoked vulvodynia remains unclear, but an interplay of biomedical and psychosocial mechanisms is believed to contribute to the onset. The choice of treatment for provoked vulvodynia depends on locally available resources. Internet interventions can reach patients in distant geographical areas and may thus promote equal access to healthcare services. A few studies have investigated the effects of cognitive behavioral therapy on provoked vulvodynia. However, there appear to be no studies of the effects of an internet intervention using an acceptance and commitment therapy approach, also called third-wave cognitive behavioral therapy, for women with provoked vulvodynia.

    The aim of this thesis was to investigate the effects and patient experiences of a guided internet-based intervention for women with provoked vulvodynia during the waiting period for clinical treatment. All four studies included in this thesis were tied to a multicenter randomized controlled study: the EMBLA study. Participants were randomized to a six-week guided internet intervention or a waiting list before treatment as usual. Pain during intercourse, other pain-related variables, and pain acceptance were variables used to assess the effects of the intervention. Later, interviews were carried out with participants to ascertain their experiences of this internet-based treatment. Lastly, health-related quality of life and healthcare utilization were assessed to obtain a health economic evaluation of the intervention. 

    Internet-based treatment had a positive effect on pain during intercourse and pain acceptance, but the results should be interpreted with caution due to the small sample size. This form of treatment was perceived as credible and helpful for managing provoked vulvodynia, but some difficulties related to the internet-based treatment were also reported. The intervention contributed to meaningful clinical effects at low costs per patient, indicating that internet-based treatment is not inferior to the standard of care. Internet-based treatment may serve as a complement to regular care, especially for patients living in geographical locations with low access to specialized care or where there are long waiting lists to initiate treatment.

  • Understanding Adhesive Mixtures for Inhalation : Particle Dynamics Modelling and Segregation Experiments Author: Sohan Sarangi Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-483090 Publication date: 2022-09-29 09:46

    Pulmonary route has been used as a source of drug delivery to lungs for centuries. Drugformulation decides the type of inhaler devices such as pressurized metered-dose inhalers(pMDIs), nebulizers and dry powder inhalers (DPIs). The most commonly used formulationin DPI consists of an ordered unit consisting of smaller drug particles (3 to 5 μm) (activepharmaceutical ingredient, API) attached to larger inert particles (carrier particles, 100 μm)called adhesive mixtures. APIs are highly cohesive in nature due to high surface to volume ratio.The adhesive mixture prevents self-agglomeration of APIs and helps deliver it to the deep lungs.In the manufacturing of adhesive mixtures, the focus has been on mixing and release insideinhaler. The research work in this thesis focuses on unaddressed issues on mixture stability andsegregation using modeling and experimental techniques. The Discrete Element Method (DEM)was used to investigate the mechanics of adhesive units, formed by randomized distributionof APIs on the surface of carrier particle. Binary collisions (head on and oblique) betweenadhesive units were simulated for different number density of fines on the carrier (surfacecoverage ratio, SCR), surface energy (interfacial adhesion/cohesion energy), shape of APIs(spherical, triangular bipyramidal and tetrahedral), size of carrier particles (50, 100, 200 μm),type of carrier particle (lactose and mannitol) and the angle of impact. To account for variationthree different initial randomized distributions of API on the carrier were considered. The dataobtained was analysed in terms of effective mechanical properties (coefficient of restitution),effective friction, physical stability of adhesive unit and redistribution of fines on the carriersurface. The coefficient of restitution follows a Kawakita type equation for higher velocity andfor different surface energy. The effect of the fine particle shape was predominant for low SCRs,and adhesive units formed from tetrahedral fines exhibited the largest physical stability andlargest friction during oblique collisions. In terms of carrier size and properties it was observedthat mannitol particles are more stable than lactose with similar dispersion performance andthe200 μm carrier is the most stable among the sizes investigated. To complement the modeling,segregation of adhesive mixture (consisting of budesonide and salbutamol sulphate as APIand Inhalac 70 as carrier) was studied. Experiments showed significant loss of APIs and selfagglomeration at higher SCR. The micro mechanical models and experiments lay a foundationtowards a better understanding of the adhesive mixture dynamics.

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