Human Embryonic Stem Cells - Constitutive Gene Expression and Differentiation Towards Definitive Endoderm and Posterior Foregut Endoderm

Abstract More than 300 million people are suffering from diabetes worldwide and the numbers of diabetic patients are increasing. Today´s treatments mainly rely on daily insulin injections. This help people to control blood glucose levels but still many patients suffer from the many complications associated with diabetes. Transplantations of islet cells are an alternative treatment that could help patients to become insulin independent and presumably also delay the development of complications. However, the increasing number of diabetic patients would require large amounts of transplantable insulin producing cells. Due to the fact that islet donor material is a limiting factor for transplantations, human embryonic stem cells (hESCs) could be an alternative source of transplantable insulin producing cells. hESCs have the unique potential to self-renew and to differentiate to many cell types, presumably also beta cells. In order to generate therapeutically relevant beta cells, the scientific community focuses on recapitulating the embryonic processes behind beta cell development. In order to develop protocols that direct differentiation of hESCs along the developmental program of pancreas development, cellular markers and methods that allow the identification and isolation of cells that displays a correct phenotype of each developmental stage are fundamental research tools. Identification of definitive endoderm (DE) - from where pancreas originates, requires analysis methods that can detect multiple markers within individual cells, since many markers expressed in DE are also detected in extraembryonic endoderm. In this thesis, we approached single cell gene expression analysis of hESCs differentiated towards DE to provide insight about expression of a panel of DE markers at the cellular level. Some of these markers have conventionally been measured by gene expression analysis at the population level and little information is available about expression at the cellular level in differentiating hESCs. To differentiate hESCs towards DE three different methods of activin A treatment were used. Single-cell gene expression analysis identified distinct gene expression signatures both between the activinA treated populations and within each population. Within the SOX17+ population, the DE markers CER1 and FOXA2 were co-expressed in the majority cells independent of activin A treatment. By contrast, HHEX, CXCR4, FOXA2, MIXL1 and LIM1/LHX1 were expressed to various extents within the SOX17+ populations of each activin A treatment. These data provides novel insight in DE gene expression at the cellular level of vitro differentiated hESCs and illustrates the usefulness of single-cell gene expression analysis in to identify the molecular signature of in vitro differentiated hESCs. Thus, this technique could be of great help to develop protocols that mimics pancreas development in vivo. Furthermore, this thesis includes work that test the ability of RA and FGF4 alone or in combination to direct differentiation of hESCs towards PDX1+ foregut endoderm. The rationale for this was that both RA and FGF signaling exhibit a patterning effect during endoderm patterning and also supports pancreas specification. By optimizing the timing and concentration of RA and FGF4, it was shown that RA is required to convert activin A-induced hESCs into PDX1+ cells and that part of the underlying mechanism involves FGF signaling. Characterization of the PDX1+ cells suggests that they represent posterior foregut endoderm not yet commited to pancreatic, posterior stomach or duodenal endoderm. Directed differentiation of hESCs would greatly benefit from a deeper understanding of the molecular mechanism that regulate growth and differentiation. To approach these questions, efficient genetic engineering techniques are advantageous tools for controlled expression of genes or to introduce fluorescent reporter genes. Constitutive promoters are useful tools due to their high level of expression in most cell types. Different eukaryotic/mammalian and viral constitutive promoters have been reported to ensure high level and sustained activity in hESCs but a comprehensive study was lacking. In this thesis, we performed a comparative study the activity and stability of five commonly used promoters in undifferentiated hESCs and during differentiation. These data suggested ACTB, EF1α and PGK promoters as the most stable promoters during long term culture of undifferentiated hESCs. During EB differentiation, activities of all five promoters were downregulated and EF1α was the most stable promoter although it was downregulated in 50% of the cells. Gene expression analysis of differentiated cells indicated that promoter activities might be restricted to specific cell lineages, indicating the need to carefully select optimal promoters for constitutive gene expression in differentiated hESCs

The potential of starch

This is a study written as a part of the Agtech 2030-project, “Increased value at the starch-and cereal protein market”, which is a collaboration between Lantmännen and the University of Linköping within the framework of the innovation platform Agtech 2030, hosted by Linköping university. This conceptual and literary based study concerns modification of wheat starch, one of many parts of the project from Agtech 2030. There are different methods of how to modify wheat starch with the emphasis in this paper on physical and chemical modifications. The study also gives examples of food applications of modified wheat starch. The result shows that the main difference between the two mentioned types of modifications are: (1) physical modifications change the starch on a granular level and does not require chemical agents. (2) Chemical modifications can change the molecular structure of the starch e.g. by substitution of hydroxyl groups on the glucose units of the starch molecules (amylose and amylopectin). (3) There are chemically modified starches that need to be classified as food agents, whereas physically modified starch in comparison can be labelled as an ingredient in food products.Den här studien är en del av projektet, ”Ökat förädlingsvärde på stärkelse- och spannmålsproteinmarknaden” tillhörande Agtech 2030, ett samarbete med Lantmännen och Linköpings Universitet. Detta arbete är en litteraturstudie om modifierad vetestärkelse, som är en del av många delar av projektet ur Agtech 2030. Det finns olika metoder för att modifiera vetestärkelse och i den här studien läggs det fokus på fysisk och kemisk modifiering. Studien belyser även exempel av hur modifierad vetestärkelse kan användas i olika livsmedel. Resultatet visar på att den huvudsakliga skillnaden på fysisk och kemisk modifiering är följande: (1) fysisk modifiering påverkar stärkelsegranulernas struktur och kräver inga kemiska tillsatser. (2) Kemisk modifiering kan ändra den molekylära strukturen av stärkelse t.ex. genom subsitution av hydroxylgrupper på glukosenheterna som bygger upp stärkelsemolekylerna (amylos och amylopektin). (3) Det finns kemiskt modifierade stärkelser som måste klassificeras som tillsatser, jämfört med fysiskt modifierad stärkelse som i livsmedel direkt kan betecknas som ingredienser

On the semiotic function of cucurbits

Every user of the sign can get at its meaning not only through his knowledge of the code (which could have been arbitrary) but also by deducing on his own the meaning of the sign through observations of that part of nature from which it is taken. In their symbolic use in literature the various plants and animals are thus often given their semiotic role because of intrinsic suitability for it. By looking at some aspects of the semiotic role of the plant family Cucurbitaceae (melons, water-melons, cucumbers, pumpkins, gourds, calabashes, squashes, gherkins, marrows etc.), the author exemplifiesfour of the ways in which such textual elements "write themselves". One cluster of cucurbitic connotations is strongly positive. Cucurbitstropical plants, requiring warmth and moisture—are associated with summer, luxury and abundance. Being fertile plants which grow quickly (and die easily) they are a symbol of life and vitality, usually of cyclical life or the life cycle (in contrast to e.g. evergreens which tend to symbolize eternal or enduring life). Closely connected with their role in symbolizing life and fertility are their sexual connotations which are widespread, numerous and far-branching. In particular the sexual connotations abound in associations with femininity. 

Kan tillsats av ett kommersiellt inokulum öka koloniseringen av mykorrhiza och förbättra växters vigör?

Vi lever i en evigt föränderlig värld där dagens miljöförändringar i samband med en ökad population ställer höga krav på våra bönder att producera starka och motståndskraftiga grödor. Ett sätt att bemöta dessa problem kan vara att använda sig av naturliga biostimulanter i sin odling som förbättrar växternas allmänna tillstånd. En naturlig biostimulant som finns på marknaden idag är jordtillsattser som innehåller sporer från arbuskulära mykorrhizasvampar, kallade inokulum. Arbuskulär mykorrhiza är en symbios mellan växters rötter och jordlevande svampar som anses ha en positiv påverkan på plantans tillväxt och stresstålighet. I denna rapport beprövades ett kommersiellt inokulum som finns på marknaden. Inokulering gjordes på en vild art inom potatissläktet som heter besksöta (Solanum dulcamara). Besksöta är en art som kan växa i många olika habitat och får då varierande utseende beroende på miljö. För att ta reda på ifall det går att öka kolonisation av arbuskulär mykorrhiza i besksöta utformades ett försök som delades upp i diverse moment där frön tagna från vilda populationer som kommer från olika habitat först planterades och drevs upp i en odlingskammare. Det fanns även ett intresse att ta reda på ifall det fenotypiska uttrycket hos besksötan varierar beroende på vilket habitat moderplantan till fröna kommer ifrån om plantor drivs upp under samma förutsättningar. Ett inokulum applicerades till hälften av plantorna i odlingskammaren för att jämföra om denna behandling ledde till ökad kolonisation och vigör i växterna. Samma inokulum applicerades även till besksötaplantor på friland för att ta reda på ifall det är lättare eller svårare att lyckas med applikationen i odlingskammare eller på friland. Resultat från inokuleringen visar att det kommersiella inokulumet som valts inte är dugligt nog för att lyckas öka kolonisation av svampar i rötterna hos besksöta varken i odlingskammare eller på friland. Vid mätningar av plantor visade det sig dock att längdtillväxt hos plantor på friland är större hos plantor som blivit behandlade med inokulum, detta skulle kunna vara en effekt av näringen som finns i inokulumet snarare än svamparna, eller de andra svampendofyter som påträffades i inokulerade växter. Det framkom även att det fanns en viss fenotypisk skillnad mellan besksötaplantor som drivits upp från frön baserat på vilket habitat moderplantan kommer ifrån.We live in a world that is forever changing where today's environmental changes in connection with an increased population place high demands on our farmers to produce strong and resilient crops. One way to address these problems could be to use natural biostimulants to improve the general condition of our plants. A natural biostimulant available on the market today is soil additives that contain spores from arbuscular mycorrhizal fungi, called inoculum. Arbuscular mycorrhiza is a symbiosis between plant roots and soil living fungi that has a positive effect on plant growth and resistance against stress. In this report, we examined the effects of a commercial inoculum of arbuscular mycorrhizal fungi that exists on the market, on a wild species in the potato genus called bittersweet nightshade (Solanum dulcamara). Bittersweet nightshade is a species that can be found in many different habitats, their appearance varies depending on the environment they grow in. An experiment was designed to find out if it is possible to increase the colonization of arbuscular mycorrhiza equally in plants originating from different types of habitats by adding a commercial inoculum. The experiment was divided into various steps where seeds taken from wild populations in different habitats were first planted and raised in a cultivation chamber. There was also an interest in finding out if the phenotypic expression of bittersweet nightshade varies depending on which habitat the mother plant of the seeds comes from, even if the plants were raised under the same conditions. An inoculum was then applied to half of the plants in the cultivation chamber. The same inoculum is also applied to bittersweet nightshade plants in a trial field to find out if the application was more successful in the cultivation chamber or under field conditions. Results from the inoculation show that the commercial inoculum failed to increase the colonization rates of arbuscular mycorrhizal fungi in the roots, both in the cultivation chambers and in the field. When plants were measured, it turned out that the overall growth of plants from the field was greater in plants that had been treated with the inoculum, this may be an effect of the nutrients present in the inoculum rather than the fungi or the dark septate endophytes found in inoculated plants. Results also indicate that there is a phenotypic difference between plants of bittersweet nightshade grown from seeds based on which habitat the mother plant comes from

Model development and transient analysis of the wcll bb bop demo configuration using the apros system code

Extensive modelling and analytical work has been carried out considering the water-cooled lithium–lead breeding blanket (WCLL BB) balance of plant (BOP) configuration of the demonstration power plant (DEMO) using the Apros system code, developed by VTT Technical Research Centre of Finland Ltd. and Fortum. Contributing to the BOP work package of the EUROfusion Consortium, the integral plant model for dynamic analyses of the WCLL BB configuration has been updated with special attention to primary system components. Following trends of relevant neutronics modelling, a new BB model has been implemented in 2020 with the aim to obtain higher resolution output data and a more realistic thermalhydraulic feedback from the primary system. Once-through steam generator user components have been built based on CAD models conceived by BOP partners. Transient analyses have been performed providing a better picture regarding the behaviour of main components, e.g., the BB and the OTSGs, whilst highlighting possible ways to optimise the control scheme of the plant

Evaluating contamination exposure rates in different Urban Agriculture (UA) practices

Introduction: Urban Agriculture (UA) is instrumental in instilling a degree of self-sufficiency in food production inevitable for a resilient and sustainable city. Nevertheless, urban soil can be a substantial source of contamination due to previous, ongoing or even adjacent land-use like heavy traffic, and consumption of fresh produce grown on such could be an added exposure pathway for the urban population. These concerns lead many countries to follow strict regulation for gardening in urban areas bracketing it with residential use accentuating the exposure risks. But there are many UA practices with varying degree of user involvement and management; the prevalent ones taking place well-out of the residential periphery. However, there exist neither a definitive soil screening guideline that refers to such variations of UA practices nor studies on UA scenarios to modify the existing risk models.Methods: This study identifies different UA scenario and compares the contamination exposure to highlight the difference of risk in them. An exposure risk model is created combining with UA scenario sensitive parameters to test on five different practices; house garden, allotment garden, neighbourhood greenspace, meadow orchard and arable land. The scenario exposure data is to be collected from surveying different UA practice group in Gothenburg, Sweden. \ua0Results: The preliminary result with elicited data shows that practices with residential or extensive use such as house garden, neighbourhood greenspace and arable land predictably have high risk.\ua0 More common UA uses such as allotment gardens are much less risky when exposed to the same concentration of contamination while dropping to almost none for meadow orchards.Conclusion: Retrofitting abandoned, and derelict lands allow UA to find a place in the competitive urban land market. More knowledge on the exposure from soil contamination from different UA practices would provide more options to bring back obsolete land in use

Podcasts As A Learning Method In Engineering Education

Multimedia has been integrated in education the last 40 years but podcasts have more recently become popular. Since 2006 podcasts have become increasingly popular in Sweden and nowadays podcasts are used in all types of contexts but are yet to find a place in engineering education. Students do not acquire knowledge or solve problems in the same way. Using a mix of methods in teaching is therefore important if one has the ambition to democratize the learning processes and give students the same opportunity to learn. Traditionally, much of the university education has been based on lectures in classrooms and reading literature. During the pandemic, teachers switched to video lectures and online lectures. Even though all types of multimedia are involved in teaching today, podcasts have not become established as a learning method. This paper explores in what ways podcasts can be beneficial in engineering education. Specifically, the paper investigates what preferences students have on how podcasts for engineering education and how teachers effectively can design and develop podcasts in courses as a learning method. By addressing the gap of evidence on podcasts in engineering education, the findings contribute with effective solutions on how podcasts can be developed and implemented that will help students in their learning processes. © 2023 SEFI 2023 - 51st Annual Conference of the European Society for Engineering Education: Engineering Education for Sustainability, Proceedings. All Rights Reserved