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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

The synthesis of well-defined functional homo- and block copolymers in aqueous media via Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization

Mertoglu, Murat January 2004 (has links)
New chain transfer agents based on dithiobenzoate and trithiocarbonate for free radical polymerization via Reversible Addition-Fragmentation chain Transfer (RAFT) were synthesized. The new compounds bear permanently hydrophilic sulfonate moieties which provide solubility in water independent of the pH. One of them bears a fluorophore, enabling unsymmetrical double end group labelling as well as the preparation of fluorescent labeled polymers. Their stability against hydrolysis in water was studied, and compared with the most frequently employed water-soluble RAFT agent 4-cyano-4-thiobenzoylsulfanylpentanoic acid dithiobenzoate, using UV-Vis and 1H-NMR spectroscopy. An improved resistance to hydrolysis was found for the new RAFT agents, providing good stabilities in the pH range between 1 and 8, and up to temperatures of 70°C. Subsequently, a series of non-ionic, anionic and cationic water-soluble monomers were polymerized via RAFT in water. In these experiments, polymerizations were conducted either at 48°C or 55°C, that are lower than the conventionally employed temperatures (>60°C) for RAFT in organic solvents, in order to minimize hydrolysis of the active chain ends (e.g. dithioester and trithiocarbonate), and thus to obtain good control over the polymerization. Under these conditions, controlled polymerization in aqueous solution was possible with styrenic, acrylic and methacrylic monomers: molar masses increase with conversion, polydispersities are low, and the degree of end group functionalization is high. But polymerizations of methacrylamides were slow at temperatures below 60°C, and showed only moderate control. The RAFT process in water was also proved to be a powerful method to synthesize di- and triblock copolymers including the preparation of functional polymers with complex structure, such as amphiphilic and stimuli-sensitive block copolymers. These include polymers containing one or even two stimuli-sensitive hydrophilic blocks. The hydrophilic character of a single or of several blocks was switched by changing the pH, the temperature or the salt content, to demonstrate the variability of the molecular designs suited for stimuli-sensitive polymeric amphiphiles, and to exemplify the concept of multiple-sensitive systems. Furthermore, stable colloidal block ionomer complexes were prepared by mixing anionic surfactants in aqueous media with a double hydrophilic block copolymer synthesized via RAFT in water. The block copolymer is composed of a noncharged hydrophilic block based on polyethyleneglycol and a cationic block. The complexes prepared with perfluoro decanoate were found so stable that they even withstand dialysis; notably they do not denaturate proteins. So, they are potentially useful for biomedical applications in vivo. / Ziel der vorliegenden Arbeit war es, neue Kettenübertragungs Agenzien, basierend auf Dithiobenzoat- und Trithiocarbonatderivaten zu synthetisieren, welche in der "Reversiblen Additions-Fragmentierungs Kettenübertragungs-Polymerisation" (RAFT) eingesetzt werden können. Die neu synthetisierten Verbindungen zeichnen sich durch permanent hydrophile Sulfonatgruppen aus, welche eine pH-unabhängige Löslichkeit in Wasser ermöglichen. Eine dieser Verbindungen trägt ein Fluorophore, wodurch eine asymmetrische doppelte Endgruppenmarkierung sowie die Herstellung von Fluoreszenzmarkierten Polymeren möglich ist. Die Hydrolysestabilität dieser Verbindungen in wässriger Lösung im Vergleich mit dem z. Zeit bekanntesten wasserlöslichen RAFT Agenz (4-Cyano-4-thiobenzoylsulfanylpentansäuredithiobenzoate) wurde unter Anwendung spektroskopischer Methoden (UV-Vis, 1H-NMR) untersucht. Dabei wurde festgestellt, dass diese neue Verbindungen deutlich bessere Hydrolysestabiltäten im pH-Bereich von 1-8 und bis zu einer Temperatur von 70°C besitzen. Die neuen RAFT-Verbindungen wurden ebenfalls bezgl. Ihrer Eignung in der Polymerisation von wasserlöslichen nichtionischen, anionischen und kationischen Monomeren in wässrigem Medium bei 48°C und 55°C getestet. Unter diesen Bedingungen konnten Vinylverbindungen wie z. B. Styrenderivate. Acrylate und Methacrylate kontrolliert polymerisiert werden: Die Molmasse stieg mit dem Umsatz, die Polydispersitäten waren niedrig und die isolierten Polymere zeigten Grad an Endgruppenfunktionalität. Bei der Polymerisation von Methacrylamiden wurde bei Polymerisationstemperaturen unter 60°C nur eine mäßige Kontrolle gefunden. <br><br> Es konnte weiterhin die RAFT Polymerisation in Wasser als leistungsstarke Methode zur Herstellung definierter Di- und Triblockcopolymere, einschließlich der Synthese von funktionalen Polymeren mit komplexer Struktur – beispielsweise amphiphiler- und schaltbare (stimuli responsive) Blockcopolymere entwickelt werden. Dies beinhaltet auch Polymere, die einen oder zwei schaltbare hydrophile Polymerblöcke enthalten. Der hydrophile Eigenschaft eines oder mehrer Blöcke kann durch äußere Reize wie pH-Änderung, Temperatur oder Salzgehalt geändert werden. Diese Beispiele demonstrierten die Variabilität des für schaltbare Polyamphiphile notwendigen Designs und zeigten exemplarisch das Konzept für multi-sensitive Systeme.
82

Arga röster ökar muskelanspänningen / Angry voices increase muscle tension

Gustafsson, Karin January 2012 (has links)
Syftet var att undersöka om exponering inför emotionella röster påverkar muskelanspänning och hjärtats slagfrekvens samt om det finns en samvariation mellan storlek eller längd på muskelanspänning vid aversiv emotionell input och grad av alexitymi. 24 studenter lyssnade på arga, glada och neutrala röster samtidigt som muskelanspänning mättes med EMG och hjärtats slagfrekvens med EKG. Grad av alexitymi mättes med Toronto Alexithymia Scale 20. Resultaten visade att arg eller glad röststimuli gav större muskelanspänningen än neutralröststimuli. Ingen skillnad i muskelanspänning fanns mellan arg eller glad röst. Det fanns inget samband mellan storlek eller längd på muskelanspänning och grad av alexitymi. / The object was to investigate whether exposure to emotionally valid voices, affect muscle tension and heart rate, and if there is a correlation between size or length of muscle tension during aversive emotional input and degree of Alexithymia. 24 students listened to angry, happy and neutral voices while muscle tension was measured by EMG and heart rate by EKG. Degree of Alexithymia was measured by Toronto Alexithymia Scale 20. The results showed that angry or happy voice stimuli caused higher muscle tension than neutral voice stimuli. No difference in muscle tension was shown between angry and happy voice. There was no correlation between size or length of muscle tension and degree of Alexithymia.
83

Tissue Engineering des Humanen Cornealen Endothels

Teichmann, Juliane 17 January 2014 (has links) (PDF)
Das corneale Endothel bildet die innere, einschichtige Zelllage der Cornea und ist für die Aufrechterhaltung der cornealen Transparenz zuständig. Krankheiten oder Verletzungen des cornealen Endothels können zu schweren Beeinträchtigungen des Sehvermögens führen und eine corneale Transplantation erforderlich machen. Der während und nach der Operation auftretende endotheliale Zellverlust erschwert das Überleben des Transplantates. Darum besteht ein Hauptziel des cornealen Tissue Engineerings in der Bereitstellung von transplantierbaren humanen cornealen Endothelzellsheets (HCEC-Sheets) mit einer adäquaten Zelldichte. Thermo-responsive Zellkulturträger fanden für die schonende, enzymfreie Gewinnung von Zellsheets für verschiedene Gewebetypen bereits Verwendung. HCEC stellen in diesem Kontext einen besonderen Fall dar, da sie eine starke Adhäsion zu ihrem Kultursubstrat ausbilden, was deren schonende, thermisch induzierte Ablösung als funktionelles Zellsheet erschwert. Im Rahmen dieser Arbeit wurde ein neuartiger thermo-responsiver Zellkulturträger entwickelt. Dieser basiert auf dem durch Elektronenbestrahlung immobilisierten und vernetzten thermo-responsiven Polymer Poly(vinylmethylether) (PVME) sowie dem alternierenden Co-Polymer Poly(vinylmethylehter-alt-maleinsäureanhydrid) (PVMEMA) als biofunktionalisierbare Komponente. Die Kombination dieser Polymere führte zur Etablierung eines thermo-responsiven Zellkulturträgers, dessen physikochemische und biomolekulare Eigenschaften in weiten Grenzen einstellbar und dadurch an die spezifischen Anforderungen von HCEC anpassbar waren. Das PVME-PVMEMA-Blend ermöglichte die Bildung konfluenter HCEC-Monolayer mit den morphologischen Grundlagen für ein funktionelles corneales Endothelgewebe. Durch Inkorporation von Poly(N-isopropylacrylamid) (PNiPAAm) als weitere thermo-responsive Polymerkomponente konnte das Ablösungsverhalten funktioneller HCEC-Sheets weiter verbessert werden. In einem weiteren Schritt erfolgte der Transfer abgelöster HCEC-Sheets auf ein planares, biofunktionalisiertes Kultursubstrat sowie auf endothelfreie porcine Corneae. Die HCEC-Sheets wurden auch nach dem Transfer umfassend biologisch analysiert. Diese Arbeit legt einen Grundstein für die Bereitstellung klinisch anwendbarer Alternativen für das Tissue Engineering von cornealem Gewebe.
84

Examining convergence of emotional abilities using objective measures / Undersöka konvergens av emotionella förmågor med objektiva mått

Paulsson, Niklas January 2018 (has links)
Recent developments in emotion and EI research have introduced new ways of measuring emotional abilities, including performance based tests. The current study aimed to examine the associations of three emotional abilities, using three objective measures. The study consisted of a survey and an experiment, where 89 participants completed performance based multimodal emotion recognition and emotion understanding tests, and a conditioning task using social aversive and appetitive stimuli. The results showed that individuals who are more proficient in emotion understanding were more accurate in emotion recognition and more effective in extinguishing fear-evoking responses. In addition, individuals proficient in emotion recognition were shown to have stronger general responding during fear acquisition. Furthermore, various findings related to emotion understanding and emotion recognition modalities, including item difficulty and specific emotions. Implications of current findings support the notion of separate but related emotional abilities while also highlighting a potentially underlying mechanism or core emotional competence.
85

Nudging för att främja beteenden : En undersökning av Högskolerestauranger ABs klimatmärkning

Sjöberg, Malin, Silawiang, Saranya January 2018 (has links)
Studien avser undersöka Högskolerestauranger AB:s projekt angående klimatmärkningen som infördes på deras menyer i Uppsala under hösten 2017. Den första delen av studien undersöker hur projektet startade, vad projektet innefattar samt Högskolerestauranger AB:s samarbete med Uppsala Kommun och CarbonCloud. Den andra delen omfattar en enkätundersökning med Högskolerestauranger AB:s lunchrestaurang Bikupans gäster där avsikten är att undersöka effekten av klimatmärkningen på kunderna. Restauranggästernas beslutsfattande gällande matval jämfördes utifrån huruvida klimatmärkning förekom på menyn eller ej. Enkätundersökningen fann att respondenter påverkades av klimatmärkningen till en viss del. Störst utfall observerades vid nötkött då denna köttyp ger mest markant markering på menyn. Om kunden anser att klimatmärkningen är relevant nog att tas i beaktning kommer denne påverkas av nudging annars kommer dess interna stimuli att vägra tyngre, vilket innebär att det beslut som tas beror till största delen av den egna känslan. Resultatet visar även att en större andel respondenter valde en maträtt med lägre klimatavtryck när klimatmärkning var närvarande på lunchmenyn.
86

Les corrélats cérébraux de la pédophilie : étude en imagerie par résonance magnétique fonctionnelle / Brain correlates of pedophilia : a functional magnetic resonance imaging study

Cazala, Fadwa 19 November 2014 (has links)
En dépit d’une littérature abondante étudiant les bases cérébrales de l’excitation sexuelle chez l’homme sans trouble, celle-ci reste plus restreinte dans l’étude de la pédophilie dont les corrélats cérébraux sont encore peu connus. La présente thèse se propose d’étudier, en IRMf, les activations cérébrales de 13 pédophiles hétérosexuels et 12 pédophiles homosexuels, appariés à 24 témoins sans trouble, en réponse à des photographies d’enfants en maillot de bain (fillettes/garçons) et d’adultes (femmes/hommes) dévêtus, les stimuli contrôlent représentant des adultes et enfants habillés normalement. Les résultats montrent que les activations cérébrales des pédophiles et témoins hétérosexuels et homosexuels, en réponse à leurs stimuli préférés ne diffèrent pas. Ces activations impliquent des régions occipitales, temporales et pariétales mises en évidence dans les corrélats cérébraux de l’excitation sexuelle chez les sujets sans trouble. En accord avec les résultats de la pléthysmographie pénienne, les analyses révèlent que les pédophiles homosexuels et hétérosexuels pourraient traiter les stimuli d’enfants du genre non préféré comme sexuellement pertinents. Ces résultats s’expliqueraient par le modèle bipolaire selon lequel l’excitation sexuelle pourrait varier selon une dimension bipolaire définie par la similitude physique, où femmes et hommes adultes se situent aux extrêmes et fillettes et garçons se situent au milieu. / In contrast to the numerous studies about the neural underpinnings of normal sexual motivation, brain correlates of pedophilia are still largely unknown. The present thesis aimed to identify functional networks involved in pedophile sexual arousal. Therefore, we investigated with fMRI the activation profile of 13 heterosexual and 12 homosexual pedophiles, compared to each other and to 24 matched healthy subjects, in response to visual sexual stimuli depicted adult (women/men) and child (girls/boy) wearing swimsuits, while neutral ones depicted ordinarily dressed adult and dressed children. Results showed that brain responses of heterosexual and homosexual pedophiles were not statistically different from those of matched healthy subjects, in response to their respective preferred stimuli. They were located in occipital, temporal and parietal brain areas known to be involved in sexual arousal in healthy subjects. In the line of penile plethysmographic studies, analysis also showed that homosexual and heterosexual pedophiles may process non preferred child stimuli as relevant sexual stimuli. This could be explained by a bipolar dimension of morphological similarity, on which children are located near the middle, and adult men and women are located at opposite ends.
87

Vocal Pitch-Matching: The Effect of Singing into the Right Ears of Fifth-Grade Students

Watkins, Sharon C. (Sharon Carp) 08 1900 (has links)
This study investigated whether fifth-grade students would sing more accurately when responding to pitch stimuli presented to the right ear as compared to left and both ears. Students were also classified as either strongly right-handed or other (left-handed or mixed) to see if ear treatment responses would differ with handedness. Sixty-six students were tested on their attempts to match 12 model pitches. Identical tests were given to each subject on 3 different days, with a different ear treatment each day. Vocal response scores were significantly better for both-ear presentation than for left-ear. No significant difference was found between right and both ears, right and left ears, or between handedness groups.
88

Patientvila på intensivvårdsavdelning under dagtid : Utopi eller verklighet? / Daytime resting in intensive care unit : Utopia or reality?

Bayat, Donia, Lindborg, Ewa January 2011 (has links)
Bakgrund: Patienter i behov av intensivvård är även i behov av en plats av lugn och ro för läkning. Intensivvården är en miljö som utsätter patienter för frekventa stimuli dygnet runt. För att få möjlighet till både fysisk och psykisk läkning krävs fullständig sömn. Intensivvårdspatienter har mer ytlig sömn på grund av att sömnrytmen ofta är störd. Genom att vila mitt på dagen i sammanhängande 90 minuter kan individen kompensera för en otillräcklig nattsömn. Bristen på vila och sömn är en komplikation som bidrar till sämre hälsa och kan leda till akut förvirringstillstånd, förlängd vårdtid och högre vårdkostnader. Syfte: Syftet var att kartlägga intensivvårdspatienters perioder med och utan fysiska stimuli under dag- och kvällstid (07.00-21.30). Metod: Författarna samlade in data som icke deltagande observatörer. Sövda och intuberade patienter placerad på flerbäddssal valdes. Alla närvarande på sal som kom i kontakt med patient observerades, alla fysiska stimuli registrerades på ett observationsschema. Resultat: Under dag- och kvällstid var det ingen av patienterna som fick en period på lika med eller mer än 90 minuter av vila. Slutsats: Patienterna på intensivvårdsavdelningen hade dålig möjlighet att under dagtid kompensera för en störd nattsömn. / Background: Patients in need of intensive care also require a calm surrounding for healing. Intensive care units have an environment which exposes the patients to frequent stimuli at all hours of the day. In order to be able to heal both physically and mentally a sufficient sleep quality is needed. Intensive care patient have a more superficial sleep as their sleep cycle is often disturbed. By being able to rest for 90 minutes consecutively during daytime the patient is given the opportunity compensate for an inadequate night sleep. The lack of rest and sleep is an issue that can contribute to a worsening of the health and can lead to delirium, prolonged hospital stay and health costs. Aim: The aim of this study was to chart the intensive care patients periods with and without physical stimuli during day- and evening time (07.00-21.30). Method: The authors collected data as non-participant observers. Sedated and intubated patients placed in multi-bed rooms were selected. All staff and family in direct contact with the patients were observed. All physical stimuli were registered on a observation-schedule. Result: None of the observed patients had a period of 90 minutes or longer of rest during day- or evening time. Conclusion: Patients at the intensive care unit had poor opportunity to compensate for a disturbed night sleep during the day.
89

Breakable silica nanoparticles for the in vitro and in vivo delivery of biomolecules / Nanoparticules de silice cassables pour le relargage in vitro et in vivo de biomolécules

Dentinger, Mike 12 December 2018 (has links)
Le travail de recherche de cette thèse se concentre sur le développement de nanoparticules de silice organo-hybrides pour des applications en nanomédecine et agroalimentaire. Ces nanoconteneurs de silice, comportant des liens disulfures, sont capables de se briser en petits fragments en présence du milieu réductif intracellulaire. Des nanoparticules présentant de larges pores ont été synthétisées pour la livraison d’un siRNA PLK1 pour le traitement du carcinome hépatocellulaire et ont démontré des résultats prometteurs in vitro et in vivo. Ces particules ont été également utilisées pour charger un peptide cytotoxique, souvent utilisé comme pesticide dans l’industrie agroalimentaire. Les nanoparticules cassables ont ensuite été miniaturisées pour le relargage d’agents thérapeutiques dans des glioblastomes humains. Le système présentait un relargage plus rapide comparé à la forme liposomale actuellement sur le marché. Enfin, des nanoparticules contenant des liens répondant aux réactifs dérivés de l’oxygène ont été développées et ont démontré une fragmentation importante en présence d’oxygène singulet. / The research work presented throughout this thesis focuses on the development of organo-hybrid mesoporous silica nanoparticles for their applications in nanomedicine and crop industry. Disulfide doped silica nanocarriers, able to break down in small pieces in presence of the intracellular reductive environment have been tailored. A large pore stimuli-responsive system was developed to deliver a PLK1 siRNA within hepatocellular carcinoma cells demonstrating promising results both in vitro and in vivo. The particles were further used to deliver a venom peptide, often utilized as esticide in the crop industry. The breakable nanocarriers were further miniaturized for the delivery of chemotherapeutic agents within human glioblastoma cells. The system presented a faster delivery compared to the commercially available liposomal form. Finally, Reactive-Oxygen-Species-responsive mesoporous silica nanoparticles were developed and demonstrated fast breakability upon incubation with singlet oxygen.
90

Beteenderespons hos rådjur (Capreolus capreolus) på akustiska stimuli / Behavioural response of roe deer (Capreolus capreolus) to acoustic stimuli

Ljungberg, Felicia January 2023 (has links)
Humans can influence the habitats that animals use by, for example, building railways that form barriers in the landscape, which disturb the animals and reduce their habitats. During the last ten years, wildlife accidents on railways have increased dramatically, and the measures to reduce accidents, such as building fences and wildlife passages, are very expensive. Acoustic stimuli can be used to scare roe deer away from different locations. Both experience and natural selection have affected animals and their behavior when they are exposed to threats from predators. The magnitude of the perceived threat and the degree of fear motivates which behavioral response is used. Some responses to threatening situations are flight, increased vigilance, and reduced foraging behavior. The purpose of this report is to investigate which acoustic stimuli cause the roe deer to leave the location and how much time they spend eating and being vigilant. By filming the roe deer when they were exposed to six different acoustic stimuli, human voice, dog barking, warning call from roe deer, pink noise, bird sounds and silent control, at feeding stations at Grimsö Research Station, I tested the influence of different stimuli on the behavior of roe deer. The results showed the roe deer spent the most time eating during a silent control period, when undisturbed. The pink noise and the human voice can possibly be used to ward off roe deer from the railroad tracks before the train arrives. The sound of dog barking and warning calls from another roe deer make the roe deer alert but the deer most often remain on the spot. Further investigations of acoustic stimuli are required to know the effectiveness of different stimuli to best avoid wildlife accidents in train traffic. / Människan kan förändra djurens habitat genom att bygga järnvägar som utgör barriärer i landskapet vilket stör djuren och minskar deras livsmiljöer. Under de senaste tio åren har viltolyckor på järnvägen ökat markant. Genom att bygga viltstängsel samt faunapassager kan man minska viltolyckorna och djuren kan röra sig naturligt i landskapen, ett problem är dock att djur kan bli påkörda vid farliga passager och att dessa åtgärder är väldigt dyra. Olika typer av akustiska signaler kan användas för att skrämma bort rådjur från olika platser. Både erfarenheter och naturligt urval har gjort att bytesdjur anpassat sitt beteende när de blir utsatta för hot av predatorer. Hur stort hotet upplevs och graden av rädsla motiverar vilken beteenderespons som används. Några responser på hotfulla situationer är flykt, ökad vaksamhet och minskat födosöksbeteende.  Syftet med denna rapport är att undersöka vilka akustiska stimuli som får rådjuren att lämna platsen samt hur mycket tid de spenderar med att äta och vara vaksamma. Rådjuren filmades när de utsattes för sex olika akustiska stimuli, människoröst, hundskall, brusljud, varningsrop från rådjur, fågelljud och tyst kontroll, vid foderstationer vid Grimsö Forskningsstation. Resultatet visade att olika akustiska stimuli inducerar olika beteenderesponser hos rådjur. De spenderade mest tid med att äta under tyst kontroll när de var ostörda. Brusljudet och människorösten kan eventuellt används för att få rådjuren att lämna tågspåret innan tåget kommer. Hundskall och varningsrop från rådjur gör att rådjuren blir vaksamma men stannar kvar på platsen. Vidare undersökningar av akustiska stimuli krävs för att veta hur man på bästa sätt kan undvika viltolyckor i tågtrafiken.

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