The mechanism by which ionic lanthanum (La3+) increases and subsequently decreases spontaneous transmitter release was investigated by recording miniature endplate potentials (MEPPs) at frog neuromuscular junctions. Addition of tetrodotoxin and Co2+ delayed the onset of MEPP frequency increase but did not otherwise prevent the response. Dinitrophenol substantially reduced but did not eliminate the increase, whereas 3,4,5-trimethoxybenzoic acid8-(diethylamino) octyl ester (TMB-8) completely abolished it. Thus, La3+ does not act by depolarizing the terminal or by substituting for Ca2+ at transmitter release sites. Instead, it appears to enter the terminal through Na+ channels and promote Ca2+ release from intracellular organelles. The profound depletion of transmitter with time may be due to the high turnover of transmitter coupled with the inhibition of metabolic processes by La3+.

One of the consequences of G-protein-coupled receptor activation is stimulation of phosphoinositol metabolism, leading to the generation of IP 3 and its metabolites 1,3,4,5-tetrakisphosphate (IP4) and inositol 1,2,3,4,5,6-hexakisphosphate (IP6). Previous reports indicate that high inositol polyphosphates (IP4 and IP6) are involved in clathrin-coated vesicular recycling. In this study, we examined the effects of IP4 and IP6 on spontaneous transmitter release in the form of miniature endplate potentials (MEPP) and on enhanced vesicular recycling by high K+ at frog motor nerve endings. In resting conditions, IP4 and IP6 delivered intracellularly via liposomes, caused concentration-dependent increases in MEPP frequency and amplitude. Pretreatment with the protein kinase A (PKA) inhibitor H-89 or KT 5720 reduced the IP4-mediated MEPP frequency increase by 60% and abolished the IP6-mediated MEPP frequency increases as well as the enhancement in MEPP amplitude. Pretreatment with antibodies against phosphatidylinositol 3-kinase (PI 3-K), enzyme also associated with clathrin-coated vesicular recycling, did not alter the IP4 and IP6-mediated MEPP frequency increases, but reduced the MEPP amplitude increase by 50%. In our previous reports, IP3, but not other second messengers releasing Ca2+ from internal Ca2+ stores, is able to enhance the MEPP amplitude. In order to dissociate the effect of Ca2+ release vs. metabolism to IP4 and IP 6, we evaluated the effects of 3-deoxy-3-fluoro-inositol 1,4,5-trisphosphate (3F-IP3), which is not converted to IP 4 or IP6. 3F-IP3 produced an increase then decrease in MEPP frequency and a decrease in MEPP amplitude. In elevated vesicle recycling induced by high K+-Ringer solution, IP4 and IP6 have similar effects, except decreasing MEPP frequency at a higher concentration (10-4 M). We conclude that (1) high inositol polyphosphates may represent a link between IP3 and cAMP pathways; (2) the IP3-induced increase of MEPP amplitude is likely to be due to its high inositol metabolites; (3) PI 3-K is not involved in the IP 4 and IP6-mediated MEPP frequency increases, but may be involved in MEPP size.

1. The role of calmodulin (CaM) in transmitter release was investigated using liposomes to deliver CaM and monoclonal antibodies against CaM (antiCaM) directly into the frog motor nerve terminal. 2. Miniature endplate potentials (MEPPs) were recorded in a high K+ solution, and effects on transmitter release were monitored using estimates of the quantal release parameters m (number of quanta released), n (number of functional transmitter release sites), p (mean probability of release), and vars p (spatial variance in p). 3. Administration of CaM, but not heat-inactivated CaM, encapsulated in liposomes (1000 units ml-1) produced an increase in m (25%) that was due to an increase in n. MEPP amplitude was not altered by CaM. 4. Administration of antiCaM, but not heat-inactivated antiCaM, in liposomes (50 μl ml-1) produced a progressive decrease in m (40%) that was associated with decreases in n and p. MEPP amplitude was decreased (15%) after a 25 min lag time, suggesting a separation in time between the decreases in quantal release and quantal size. 5. Bath application of the membrane-permeable CaM antagonist W7 (28 μM) produced a gradual decrease in m (25%) that was associated with a decrease in n. W7 also produced a decrease in MEPP amplitude that paralleled the decrease in m. The decreases in MEPP size and m produced by W7 were both reversed by addition of CaM. 6. Our results suggest that CaM increases transmitter release by mobilizing synaptic vesicles at the frog motor nerve terminal.

Recent studies show that angiotensin II (AngII) can act from within the cell, possibly via intracellular receptors pharmacologically different from typical plasma membrane AngII receptors. The role of this intracellular AngII (AngIIi) is unclear. Besides direct effects of AngIIi on cellular processes one could hypothesise a possible role of AngIIi in modulation of cellular responses induced after heterologous receptor stimulation. We therefore examined if AngIIi influences [Ca2+]i in A7r5 smooth muscle cells after serotonin (5HT) or UTP receptor stimulation. Application of AngIIi using liposomes, markedly inhibited 45Ca2+ influx after receptor stimulation with 5HT or UTP. This inhibition was reversible by intracellular administration of the AT1-antagonist losartan and not influenced by the AT2-antagonist PD123319. Similar results were obtained in single cell [Ca2+]i measurements, showing that AngIIi predominantly influences Ca2+ influx and not Ca2+ release via AT1-like receptors. It is concluded that AngIIi modulates signal transduction activated by heterologous receptor stimulation.

The ongoing Covid- 19 pandemic has globally affected aspects such as health, economy and welfare all around the world. The demand for effective communication is to a very high degree a priority from the leading actors in society, such as the media, government and authorities, in order to respond to the spread of infection. The purpose of this bachelor’s essay is therefore, to study how countries like Sweden and Denmark communicate the crisis of Covid- 19, based on Arjen Boins theoretical framework of meaning-making. The frame functions consist of the following: explaining what happened, offering guidance, instilling hope, showing empathy and state responsibility. Meaning making is an important function in crisis communication to reduce political and public uncertainty through crisis communication by the political leaders in crisis management. The political leaders seeks to convince the general public by formulating a convincing message.  The design of this essay is comparative, where the methods consist of a qualitative approach through the use of text analysis. Prime ministers and state epidemiologists will be analyzed on the basis of their participation in press releases. The time period was selected between march-may 2020. The reason for the selected time period is based on the first wave of the virus.  The conclusion of this essay was that there were many similarities and differences in the countries application of meaning making. The noticeable similarities was that both countries have similar characteristics in their communication by helping the nations make sense of the crisis situation. Both countries provide the nation with guidelines which includes, social distancing, good hand hygiene and participation restrictions. However, it differs in how they communicate it. Sweden communicates the providing of guidelines through the assessment of the public health authority, which relies on the responsibility of the individual. Denmark, on the other hand, communicates the guidelines by the Prime Minister deciding on mandatory restrictions, through a total shutdown on society. Furthermore, communication differs on state responsibility, where Sweden used a different strategy which was intended to slow down the spread of infection by not shutting down society. Denmark communicated state responsibility by saying that strict measures are necessary in such types of situations, which allowed for the restriction of civil liberties and rights. The use of empathy and instilling hope were less salient, but both countries did use the strategy by informing that they will beat the spread of the virus together.

Bakgrund: Förkortad hamstringmuskulatur är vanligt bland fysiskt aktiva. Inadekvat hamstringmuskellängd och ökad styvhet i hamstringsmuskulatur är möjliga orsaker till skador i hamstring. Den senaste tiden har det blivit allt vanligare med användning av foamroller till syfte att behandla dessa förkortningar och styvhet.  Syfte: Syftet med denna studie är undersöka om användning av foamroller har någon direkt påverkan på töjbarheten och smärttolerans i hamstringsmuskulatur efter ett behandlingstillfälle. Metod: En experimentell studie utfördes där tio friska fysiskt aktiva män (ålder 25,4 ± 3 år, längd 183 ± 9,5 cm, vikt 78,5 ± 7,2 kg) med självrapporterad nedsatt rörlighet baksida lår rekryterades och genomgick två kortare behandlingar (3 x 30 sekunder), med foamroller och statisk stretch på deras dominanta ben (det ben dom sparkar boll med), vid två separata tillfällen. Mätningar av passiv rörlighet i knäled, styvhet i hamstringmuskulatur och smärttolerans på biceps femoris mest ömmande punkt utfördes före och direkt efter varje testtillfälle. Data sammanställdes och analyserades i IBM SPSS för skillnader före och efter gällande förändringar på rörlighet, styvhet och smärttolerans. Resultat: Små skillnader kunde observeras mellan behandlingarna.  Vid statisk stretch noterades en viss skillnad i styvhet på -0,76 Nm. I båda behandlingarna noterades en ytterst liten ökning i rörlighet på hamstringsmuskulaturen med större förändring i statisk stretch, +0,1 grader.  Smärttröskeln var lägre efter båda behandlingar, -125,5 kPa efter foamroller respektive -99,3 kPa efter statisk stretch. Dock visade inte resultatet på någon statistiskt signifikant skillnad i påverkan av passiv ledrörlighet, uppmät styvhet i hamstring eller smärttröskel.   Konklussion: Studien var liten och undersökte endast korttidseffekter, men resultatet talar för att det inte finns någon reell påverkan på biceps femoris styvhet eller smärttolerans med användning av foamroller. / Nej

Les travaux menés au cours de cette thèse s’inscrivent dans le cadre général de l’évaluation du terme source (relâchement de gaz de fission) en situation incidentelle de type APRP (Accident de Perte de Réfrigérant Primaire). Lors de tels transitoires thermiques, le relâchement de gaz de fission se fait par bouffées successives : une première entre 600°C et 800°C et la seconde à environ 1100°C. Ces travaux de thèse s’intéressent à cette première. Il semblerait que la bouffée à 600-800°C proviendrait du centre de la pastille combustible. L’objectif de cette thèse est d’étudier les mécanismes à l’origine de cette bouffée.Afin de mieux comprendre ces mécanismes, une étude a été menée sur l’ensemble des traitements thermiques réalisés dans la plateforme expérimentale MERARG. L’analyse de cette base de données a révélé 2 points importants : 1) Dans les conditions expérimentales de MERARG, aucune fagmentation significative du combustible n’est observée à des températures inférieures à 1000°C. 2) Le niveau de relâchement de gaz de fission entre 600°C et 800°C semble augmenter avec le temps d’entreposage du combustible.Le premier point indique que la fragmentation du combustible n’est pas une condition nécessaire au relâchement de gaz de fission dans cette gamme de température : d’autres mécanismes peuvent être à l’origine de ce relâchement. Durant l’entreposage, le combustible est soumis principalement à l’auto-irradiation α. Celle-ci a pour effet de créer des défauts dans une zone qui n’en contenait initialement pas. Nous avons démontré que la cinétique du relâchement de gaz de fission entre 600°C et 800°C est concomitante avec la cinétique de recuit de défauts d’autoirradiation α. De plus, une cinétique auto-catalytique de germination-croissance de nano-clusters de gaz a été développée et confrontée aux résultats expérimentaux. En outre, une étude sur matériaux simulants démontre que, sur des pastilles d’UO2 frittées et implantées en xénon, une irradiation en régime électronique a pour effet d’accroitre le relâchement entre 600°C et 800°C. La littérature décrit la remise en solution des bulles de gaz de fission sous l’effet d’une irradiation de ce type. De plus, lors de leur remise en solution, les gaz de fission s’insèrent dans les défauts de la structure cristalline. Lors d’un traitement thermique, le recuit des défauts entraine la mobilité des atomes de gaz de fission insérés de ces mêmes défauts. Par germination-croissance, les paires gaz/défauts rejoignent un chemin de sortie, les gaz de fission sont donc relâchés.Ce travail a donc permis de retenir l’hypothèse d’un mécanisme de relâchement de gaz de fission entre 600°C et 800°C par recuit de défauts sans fragmentation significative du combustible. / The subject of this thesis concerns the evaluation of the source term (fission gas release) in incidental situations of type LOCA (Loss of Coolant Accident) of nuclear fuels. During such thermal transients, the fission gas release is characterized by successive bursts : the first one occurring between 600 and 800°C, and a second one at about 1100°C. This work is about the first burst release. It appear that this one come from the centre of the fuel pellet. The aim of this thesis is to study the mechanisms responsible for the fission gas release between 600°C and 800°C.To this purpose, we collected more than 200 results of thermal treatments carried out using the experimental platform MERARG. The analysis of this database reveals two important results : under the experimental conditions of MERARG, no significant fragmentation of the fuel was observed at temperatures below 1000°C ; the amount of fission gas release between 600°C and 800°C appears to increase with fuel storage time.The first result suggests the fragmentation of the fuel is not a necessary condition for the release of fission gas in this temperature range. Other mechanisms may then be responsible for this gas release. During its storage, the fuel undergoes α particle self-irradiation. We demonstrate that the kinetics of fission gas release between 600°C and 800°C is simultaneous with the kinetics of the annealing of self-irradiation defects at this same temperature. The mechanism involves an autocatalytic process leading to a kinetic of fast germination-growth of gas nano-clusters. This model perfectly explains the experimental results in the database. To confirm this mechanism, a study on surrogate materials demonstrates that, in UO2 pellets sintered and implanted by Xe, irradiations in the electronic regime actually promote the release of implanted Xe at those temperatures. The re-dissolution of the fission gas bubbles by this kind of irradiation is consistent with observations in other contexts. Those conclusions allow to extend the mechanism for release to irradiated fuel.During the storage of the fuel, α self-irradiation promotes the re-dissolution of the trapped gas. The consequences of this effect are particularly important in the region close to the grain boundaries, where the concentration of defects is also larger. The irradiation mechanism increases the fraction of fission gas available for release, depleting the amount of gas initially trapped in bubbles. The gas in solution can effectively be carried by crystal defects, largely available in the irradiated fuel and whose migration at 600-800°C induces the mobility of the fission gas. When they reach an outlet path, the gas can be released from the pellet in a way consistent with the model of autocatalytic germination-growth we developed to explain the macroscopic results of the database.In conclusion, this work supports the hypothesis of a mechanism of fission gas release in the range 600-800°C via a mechanism involving the migration and annealing of defects without significant fragmentation of the fuel.

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Objectives: To determine the amount of initial fluoride release from four orthodontic bonding systems over a period of four weeks, and then to subject these materials to an external source of fluoride for recharge in order to measure the amount of fluoride re-release over another four-week interval. Additionally the surface morphology of these materials was analyzed under the scanning electron microscope in order to identify microscopic changes in the materials that may have occurred during the experiment. Methods: Four orthodontic adhesives: Fuji Ortho LC (GC America, Alsip, IL), Transbond XT (3M Unitek, Monrovia, CA), Illuminate Light Cure (Ortho Organizers, Carlsbad, CA), and Opal Seal with Opal Bond MV (Ultradent, South Jordan, UT), n=120 (30/material) were tested for fluoride release at 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. Samples (10/subgroup/material) were then recharged with an external source of fluoride (toothpaste, foam, or varnish), and retested for fluoride re-release at 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. The scanning electron microscope was utilized in order to assess each material's surface morphology before testing and after completion of the experiment (n=16). Descriptive statistics, means and standard deviations were calculated for all four materials and their subgroups at each time interval. A mixed model two-way ANOVA was run, using a level of significance of 0.05. Bonferroni multiple comparison tests were conducted using if groups were found to be statistically significantly different. To determine significant differences between fluoride release and re-release for each recharge subgroup within each material group, paired t-tests were performed for the time intervals of 24 hours, 2 weeks, and 4 weeks. For the paired t-tests, the level of significance used was 0.02 to allow for Bonferroni correction. Results: During the initial 24 hours the fluoride measurements (in mg/L or ppm) were as follows: Fuji 9.78±0.65, Illuminate 7.83±1.49, Opal 0.05±0.02, and Transbond 0.01±0.0. At the initial four weeks time point, the readings were as follows: Fuji 6.68±0.79, Illuminate 3.82±1.84, Opal 0.06±0.01, and Transbond 0.01±0.01. The greatest fluoride release came from the varnish subgroups from each of the materials at 2 weeks post re-charge: Fuji 9.16±1.53, Illuminate 7.5±3.1 (tied with foam subgroup 7.5±4.4), Opal 5.3±2.45, and Transbond 3.75±1.67. The greatest fluoride measurement for each material at the final week post-recharge was: Fuji varnish subgroup 8.3±3.58, Illuminate foam subgroup 6.5±3.5, Opal varnish subgroup 2.50±1.1, and Transbond varnish subgroup 1.72±1.82. SEM results showed an observable difference between the materials pre-experiment and post-experiment at a magnification of 50X and 500X. The Fuji foam and paste subgroups displayed surface crackling patterns at both magnifications when compared to the control and varnish samples. The Illuminate control, foam, and paste specimens all had a roughened grainy appearance, while the varnish specimen seemed to be smoothed over by the varnish material. The Transbond samples appeared to have observable differences in surface morphology at 50X, but not at 500X. The Opal paste and foam specimens appeared to have a smoother surface than both the control and the varnish samples. Conclusions: There were significant differences in release and re-release of fluoride among all four adhesives at different time intervals over a period of eight weeks. Significant increase in fluoride re-release was seen for all three of the recharge subgroups for both Opal and Transbond at each time interval. A significant increase in fluoride re-release for the Illuminate group was mainly observed at the end of second and fourth week. Though no significant increase in fluoride re-release was observed, Fuji released highest amount of fluoride during release and re-release, at all different time intervals. Fluoride varnish was the superior recharge material, as it provided the greatest fluoride measurements, followed by foam and toothpaste. There were observable changes in the surface morphology of the materials pre-experiment and post-experiment at a magnification of 50X and 500X, which may have an affect on the fluoride releasing capabilities of the materials.

The sarcoplasmic reticulum is an internal membrane system that controls the Ca²⁺ concentration inside muscle cells, and hence the contractile state of both skeletal and cardiac muscle. A key protein that that regulates the Ca²⁺ concentration in this membrane is known as the calcium release channel (CRC). The effects on Ca²⁺ dependent activation is of major importance in the study of CRC since other channel modifiers cannot effect the channel in the absence of Ca²⁺, or they require Ca²⁺ for maximum results. In this study of the high-affinity Ca²⁺ binding site, expected increases in total binding and shifts in the sensitivity of the channel to Ca²⁺ were observed when the pH increased or the solution redox status became more oxidative. Ranolazine, a drug used for treating Angina Pectoris (chest pain), desensitized the cardiac CRC activation but had no effect on the skeletal CRC. This selective desensitization may be the cause of Ranolazine's beneficial therapeutic effects. Both Ranolazine, and homocystein thiolactone (HCTL), a naturally occurring derivative of homocysteine, alters Ca²⁺ dependent activation by calcium without changing the number of channels found in the open state. Surprisingly the effect of HCTL was observed only in a reduced redox potential which leads to speculation that the formation of an alpha-carbon radical by HCTL on the cardiac CRC only occurs if select thiols are in a reduced state.

The laboratory-scale University of Cape Town (UCT) process was designed to investigate the effects of changing COD/TP ratios on the performance of biological nutrient removal (BNR) processes. Specific objectives of the research were to investigate the effects of COD/TP ratio on the rates of phosphorus removal, COD removal, nitrogen removal, PHB utilization and oxygen uptake. The system was fed with municipal wastewater and operated at 20° C. The influent COD concentration was held approximately constant while the phosphorus concentration was varied to obtained the desired COD/TP ratio. Once robust enhanced biological phosphorus removal (EBPR) has been established, the COD/TP ratios of 20, 30, 40 and 60 were investigated. The COD/TP ratio of the influent wastewater was observed to have a substantial effect upon the performance of the UCT BNR system. The amount of phosphorus removed by the system and the percent phosphorus in the aerobic zone MLVSS decreased as the COD/TP ratio increased. In addition, the amount of phosphorus released in the anaerobic zone per unit of COD removed in the anaerobic zone increased as the COD/TP ratio decreased. From this research, the amount of anaerobic COD removal required to remove 1 mg/L of phosphorus in the aerobic zone approached a minimum value as the COD/TP ratio decreased. It was also shown that PHB production increased as the COD/TP ratio increased. The highest specific oxygen uptake rate was always observed in the second aerobic reactor and tended to increase as the COD/TP ratio increased. However, the changes in the COD/TP ratio did not significant affect COD removal, nitrogen removal and the observed yield coefficient, but did strongly affect the MLSS concentration. The MLSS concentration at the COD/TP ratio of 60 was only 55% of that at the COD/TP ratio of 20. A high level of anaerobic COD removal, an elevated percent phosphorus in the waste activated sludge (WAS) and a high soluble effluent phosphorus concentration can be used as indicators that the system is operating under COD limiting conditions. Several phenomena were also observed during this research. Firstly, the performance of the UCT BNR system for EBPR was greatly enhanced by reducing the aerobic volume. Secondly, the correlation between non-oxic phosphorus release and the aerobic phosphorus uptake improved when anoxic phosphorus release was taking into consideration. This indicated that the anoxic phosphorus release was not secondary release once the aerobic zone volume was reduced. Finally, no denitrification was observed in the aerobic zone from this study, based on the assumption that 12% of nitrogen was required for bacterial growth. / Master of Science