403 research outputs found
Effect of PCL end-groups on the self-assembly process of Pluronic in aqueous media
No full textUnderstanding self-assembly of amphiphilic copolymers in aqueous solution is an important issue in many areas, e.g., in order to tailor-make carriers for drugs and genes. We have synthesized modified versions of the copolymer of type PEO-PPO-PEO (Pluronic, F127), with short (PCL(5)) or long (PCL(11)) PCL blocks at both ends. Turbidity, dynamic light scattering (DLS), small angle neutron scattering (SANS), and rheology measurements were carried out on dilute aqueous solutions of these polymers to investigate their self-assembly behavior. The DLS results clearly show that both micellization and inter-micellization can be controlled by polymer concentration, temperature, and length of the PCL block. The interplay between unimers, micelles, and clusters of micelles could be monitored and the size and size distribution of the species were determined. The SANS data could be portrayed by a spherical core-shell model at all considered conditions of temperature and concentration for F127 and PCL(5) apart from F127 at the lowest temperature measured. The SANS data for PCL(11) were described by a spherical core-shell model at low temperatures, whereas at elevated temperatures asymmetric sub-structures appeared and a cylindrical core-shell model was employed in the analysis of the data. The appearance of pronounced correlation peaks at elevated temperatures signalizes marked intermicellar interactions. The shear viscosity data revealed a minor shear thinning effect, suggesting that the interchain structures are rather stable and not easily disrupted. The work shows that PCL-modification of Pluronic has a large influence on the self-assembly process and on the final structure of the assemblies
Detection of 4 benzodiazepines in oral fluid as biomarker for presence in blood.
No full textBackground: Analysis of samples of oral fluid (mixed saliva) is increasingly being used to detect recent drug use. The aim of this investigation was to assess the suitability of testing oral fluid as a biomarker for the presence of 4 benzodiazepines in blood and its possible application in clinical settings and in research on drug use.
Methods: Paired samples of oral fluid and blood from 4080 individuals in 4 European countries were collected and analyzed for benzodiazepines using gas or liquid chromatography with mass spectroscopic detection.
Results: Concentration data for the 4 most commonly detected benzodiazepines were studied: alprazolam, clonazepam, diazepam, and nordiazepam. Large variations in oral fluid to blood concentration ratios were observed for the studied benzodiazepines. The interquartile ranges for the oral fluid to blood concentrations ratios corresponded to 88%-197% of the median values. Selecting cutoff concentrations in oral fluid that gave the best accuracy in identifying individuals with benzodiazepine concentrations in blood above chosen thresholds produced accuracies of 74%-85% and the fraction of false negatives was 9%-23%.
Conclusions: The concentration of the 4 studied benzodiazepines in oral fluid can neither be used to accurately estimate the concentrations in blood nor to correctly identify patients with blood drug concentrations below or above recommended therapeutic levels. When using analytical methods with limits of quantitation corresponding to concentrations less than 0.5 ng/mL in undiluted oral fluid, it may be used to confirm a recent intake of benzodiazepines. However, it is likely that some false negatives may occur
Estimation of Equivalent Cutoff Thresholds in Blood and Oral Fluid for Drug Prevalence Studies
No full textOral fluid is an easily available specimen for studying drug use in a cohort or population. The prevalence of drugs in samples of oral fluid is the same as the prevalence in blood if using equivalent cutoff concentrations. The cutoffs in oral fluid may be higher or lower than that in blood in accordance with the median oral fluid-to-blood (OF/B) concentration ratio, but it is also influenced by the skewness of the distribution of OF/B ratios. The aim of this study was to determine formulae for the estimation of equivalent cutoff concentrations in oral fluid and blood for 12 commonly used illegal and medicinal psychoactive drugs when oral fluid was collected with Statsure SalivaSampler(TM). Paired samples from 4,080 persons were collected and analyzed with chromatographic methods and mass spectroscopic detection. Regression formulae for the concentrations corresponding to selected percentiles in oral fluid versus the same concentration percentiles in blood were determined. The accuracy when multiplying the cutoff thresholds in blood with the average and median OF/B ratios to estimate equivalent cutoffs in oral fluid was also investigated. Prevalence regression gave the most accurate results. The regression formulae can be used to estimate equivalent cutoff concentrations in oral fluid and blood
The Household Prayers of Doctor Martin Luther and Daily Devotion at Zion Lutheran Church in Wausau, Wisconsin
No full textGjerde, Steven, K. “The Household Prayers of Doctor Martin Luther and Daily Devotion at Zion Lutheran Church in Wausau, Wisconsin.” Doctor of Ministry, Major Applied Project, Concordia Seminary, 2016. 145 pp.
This major applied project explores the use of Martin Luther’s household prayers in Christian devotional practice. Published in the Small Catechism of 1529, the household prayers (morning, evening, and table prayers) have enjoyed varying usage since that time. This study researches whether or not they may serve as a devotional resource for contemporary believers. After addressing the Biblical and theological foundations of home devotion, the literary background of the prayers, and historical studies in religious practice, the paper presents field research conducted through surveys and a journaling experiment. It concludes with recommendations for using and teaching the prayers today
On adaptation, life-extension possibilities and the demand for health
No full textA good health is important for having a good life. This is supported by surveys on happiness. However, at least after a certain age, the health state deteriorates naturally over time due to ageing. Nevertheless, research reports show that old people in average are satisfied with their health conditions. This and other empirical evidence indicate that individuals adapt to poorer health conditions. But how will this adaptation influence the demand for health services? Gjerde, Grepperud and Kverndokk will in this paper analyse the impacts of adaptation to a falling health state on the demand for health and medical care. This is done by integrating adaptation processes in the pure consumption model of Grossman. The authors will modify the consumption-model in another direction by introducing an uncertain lifetime. Model simulations show that adaptation affects the health variables by lowering the incentives to invest in health, as well as smoothening the optimal health stock path over the life cycle. Whether or not the risk of mortality is an object of choice has important effects on the joint development of the health variables.Grossman; Demand for health; Adaptation; Life extension; Ageing.
Rights of Nature: Perspectives for Global Ocean Stewardship
No full textThe development of a new international legally binding instrument for the conservation and sustainable use of marine biodiversity beyond national jurisdiction (BBNJ agreement) is in the final negotiation phase. Legal recognition of rights of nature is emerging worldwide as a fresh imperative to preserve ecological integrity, safeguard human wellbeing, broaden participation in decision-making, and give a voice to nature – but so far exclusively within national jurisdiction. In this paper, we consider how a Rights of Nature perspective might inform the BBNJ agreement. We examine Rights of Nature laws and identify four characteristics relating to: i) rights; ii) connectivity; iii) reciprocity; and iv) representation and implementation. We argue that a Rights of Nature perspective can reinforce existing ocean governance norms, inspire new measures to enhance the effectiveness and equitability of the BBNJ agreement and enable global ocean stewardship in ABNJ.Full Tex
Holocene variations in atmospheric circulation in the North Atlantic region reconstructed from lake sediments
No full textHolocene variations in atmospheric circulation in the North Atlantic region have been reconstructed, based on three individual lake sediment studies from sites along the coast of Norway and Svalbard. This thesis contributes with new palaeoclimatic reconstructions revealing variability in wind and precipitation patterns in the northeastern North Atlantic. In Paper I, we present a new record of Holocene glacier variability of Ålfotbreen ice cap in western Norway. By applying a novel approach of calibrating lake sediments with instrumental glacier mass-balance measurements we are able to extend glacier mass-balance variability as reflected in equilibrium-line altitude (ELA) changes for the last 1400 years. Our data suggest that deglaciation of Ålfotbreen occurred ~9700 cal yr BP, and the ice cap was subsequently absent or very small until a short-lived glacier event is seen in the lake sediments ~8200 cal yr BP. The ice cap was most likely completely melted until a new glacier event occurred around ~5300 cal yr BP. Ålfotbreen was thereafter absent (or very small) until the onset of the Neoglacial period ~1400 cal yr BP. The Little Ice Age (LIA) ~650-50 cal yr BP was the largest glacier advance of Ålfotbreen since deglaciation, with a maximum extent at ~400-200 cal yr BP, when the ELA was lowered approximately 200 m relative to today. The late onset of the Neoglacial at Ålfotbreen is suggested to be a result of its low altitude relative to the regional ELA. Further, we apply a known relationship between summer temperature and ELA variations at 10 glaciers in Norway (including Ålfotbreen) to reconstruct winter precipitation during the last 1400 years. In Paper II, we present a lake record from lake Hakluytvatnet at Amsterdamøya island, the northwesternmost island on Svalbard. The lake sediment archive reveals large environmental changes that have taken place at Hakluytvatnet since the Late Glacial, as detected by multi-proxy analyses including physical sediment properties and diatom analysis. A robust chronology has been established for the lake sediment core through 28 AMS radiocarbon (14C) ages, and this gives an exceptionally wellconstrained age control for a lake at this latitude (79.5°N) that is not varved. The sedimentary archive recorded the last ~13,000 years of climate change, and is the first lake record going back to the Late Glacial at this site. Our findings indicate that a local glacier was present during the Younger Dryas (YD), and we estimate YD equilibrium-line altitude (ELA) lowering. Further, we construct a new time-series reflecting precipitation-based detrital sediments entering Hakluytvatnet (i.e., runoff) covering the period from ~5000-1300 cal yr BP. We discuss our runoff record and the internal productivity of the lake towards a record of varying sea ice extent in the Fram Strait acting as a moisture source area for Hakluytvatnet. In Paper III, a late-Holocene record of storminess in Arctic Norway is reconstructed from aeolian sediment input into the coastal lake Måvatnet, Andøya island. The study site is situated at the extreme west coast of Arctic Norway; a sensitive location for changes in North Atlantic westerly winds. Through a novel approach, combining monitoring of wind-blown lake sedimentation in sediment traps with multi-proxy analyses of lake sediments we quantify the input of wind-blown sand from a westfacing beach acting as source area into lake Måvatnet during the late-Holocene. We further assess the validity of this record to represent variations in the strength of the westerlies (i.e., storminess). The high-resolution record reveals an abrupt increase in storminess synchronously with the onset of the Little Ice Age (LIA), ca. 600 cal yr BP, coeval with increased winter precipitation at Ålfotbreen (Paper I) and a strengthening of the persistent low-pressure west of Iceland (Icelandic Low) that exerts a strong effect on North Atlantic storm tracks. Further, the timing of the onset of the LIA along the coast of Norway appears to be linked to the dynamics of the large-scale atmospheric circulation systems in the North Atlantic
Definition and detection of vulnerable marine ecosystems on the high seas: problems with the “move-on” rule
No full textAbstract
Auster, P. J., Gjerde, K., Heupel, E., Watling, L., Grehan, A., and Rogers, A. D. 2011. Definition and detection of vulnerable marine ecosystems on the high seas: problems with the “move-on” rule. – ICES Journal of Marine Science, 68: 254–264. Fishing in the deep sea in areas beyond national jurisdiction has produced multiple problems related to management for conservation and sustainable use. Based on a growing concern, the United Nations has called on States to prevent significant adverse impacts to vulnerable marine ecosystems (VMEs) in the deep sea. Although Food and Agriculture Organization (FAO) guidelines for management were produced through an international consultative process, implementing criteria for designation of VMEs and recognition of such areas when encountered by fishing gear have been problematic. Here we discuss assumptions used to identify VMEs and current requirements related to unforeseen encounters with fishing gear that do not meet technological or ecological realities. A more precautionary approach is needed, given the uncertainties about the location of VMEs and their resilience, such as greatly reducing the threshold for an encounter, implementation of large-scale permanent closed areas, and prohibition of bottom-contact fishing.</jats:p
Patient specific factors predicting adherence and treatment effect of oral appliance therapy in obstructive sleep apnea
No full textThe overall objective of this thesis was to generate new knowledge about treatment with mandibular advancement devices (MAD). MAD. Adherence and MAD treatment effects were measured in patients suffering from obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) is the first-line treatment for OSA, and only patients who were non-adherent to CPAP were included in this project.
The first study assessed the effect of MAD on the apnea/hypopnea index (AHI) of an individually adjusted MAD in patients with moderate(n=82) and severe (n=34) OSA.. Nocturnal respiratory polygraphic recordings (PG) were performed at baseline and 12- month follow-up, and reduction in AHI was the primary outcome for success. The overall treatment success rate was 75%, and there was no significant difference in success rates between the moderate and severe categories. Low pre-treatment oxygen saturation (SpO2 nadir) predicted MAD failure in the multiple regression analysis.
The aim of the second study was to test whether a built-in MAD sensor was reliable compared to self-reported MAD use for one month. Patients (n=80) with all grades of OSA were included. The relative reliability was high with an intraclass coefficient (ICC) at r= 0.847.
The aim of the third study was to measure AHI change, MAD adherence in patients with all grades of OSA, and to identify partner-specific factors related to adherence. The mean AHI was reduced to half at 8 month follow-up, and sensor-measured adherence rate at follow-up was 60.1%. Mean reduction in AHI was significantly greater in the “good” than in the “poor” adherence group. From the partner perspective, good adherence to MAD was associated with signifigreater positive effects on their relationship and being able to share bedroom again.
We conclude that MAD seems to be an effective treatment alternative for all grades of OSA. Low SpO2nadir predicted a poor effect from MAD. Adherence to MAD could be reliably measured with a built-in sensor. MAD adherence is related both to the treatment effect and bedpartners’ motivational influence. Their attitude and support may be a hidden resource for improving adherence to MAD in the treatment of OSA
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