388 research outputs found
Depression in Alzheimer's disease : biomarkers and treatment
No full textDepression and Alzheimer’s disease (AD) are among the most common clinical diagnosis in older people. The relation between depression and AD is complex: depression has been shown to be a risk factor, prodromal symptom and a consequence of AD. Increased understanding of the underlying mechanisms of depression in AD may lead to early detection and differential diagnosis, and is crucial for development of novel and mechanism-based treatments.The first two studies of this doctoral thesis are exploring the associations between depressive symptoms and biomarkers of amyloid deposition and neuronal injury in patients with subjective cognitive impairment (SCI), mild cognitive impairment (MCI) and AD. The aims of the third study were to describe the use of antidepressants in patients with dementia and to explore the association between mortality risk and the use of antidepressants 3 years before the dementia diagnosis.CAIDE Dementia Risk Score is taking into account midlife risk and protective factors; age, educational level, gender, systolic blood pressure, body mass index, cholesterol level and physical activity and APOE genotyping, and can predict dementia over 20 years. The last study was focused on exploring the associations between CAIDE Dementia Risk Score and biomarkers of amyloid deposition, neuronal injury and small vessel pathology in SCI and MCI patients. Additionally we explored the capacity of CAIDE Dementia Risk Score to predict dementia in a memory clinic population.Data were obtained from Memory Clinic Karolinska University Hospital Huddinge Sweden (Study I, II and IV). In study III, two large national registries were merged: the Swedish Dementia Registry (SveDem) and the Swedish Prescribed Drug Register.In study I, analysis of the three different cerebrospinal fluid biomarkers; amyloid beta (CSF Aβ), total-tau (CSF t-tau), and phosphorylated-tau did not support the hypothesis that more severe amyloid or tau pathologies are associated with more severe depressive symptoms. In contrast, SCI and AD patients with depressive symptoms tended to have lower CSF p-tau levels and, in particular, lower CSF t-tau levels than those without depression, indicating less severe neuronal injury. In study II, we used two different analysis methods of MRI to measure medial temporal lobe atrophy and hippocampus volume. Using manual tracing of the hippocampi we found smaller left hippocampus volume in SCI patients with depressive symptoms compared to those without depressive symptoms. In contrast, AD patients with depressive symptoms had less medial temporal lobe atrophy compared with those without depressive symptoms.In study III, 20,050 patients with incident dementia diagnosed in memory clinics and registered in SveDem were included. Information on the total number of medication and all antidepressants dispensed at the time of dementia diagnosis and at the first, the second and the third year prior to dementia diagnosis was obtained from the Swedish Prescribed Drug Register. During a median follow up of 2 years, 5168 (25.8%) dementia patients died. At the time of dementia diagnosis, 5,004 (25.0%) patients were on antidepressant treatment. Use of antidepressant treatment for 3 consecutive years prior to a dementia diagnosis was associated with a lower mortality risk for all dementia disorders in general and particularly in AD.In study IV, a higher CAIDE Dementia Risk Score was associated with higher CSF t-tau levels, more severe medial temporal lobe atrophy and more severe white matter changes. For the CAIDE score including APOE, a score above 9 points was associated with lower CSF Aβ, more severe medial temporal lobe atrophy and more severe white matter changes. CAIDE Dementia Risk Score (version with APOE) performed better at predicting AD compared with CAIDE Dementia Risk Score without APOE.Conclusion: We found that depressive symptoms in patients with AD and SCI are not associated with more amyloid deposition nor more neuronal injury compared with AD and SCI patients without depressive symptoms. Thus our results are consistent with the hypothesis that the mechanisms underlying depression differ between older people with and without AD. Our results have shown that use of antidepressants in prodromal AD stages is associated with a lower mortality risk. Further longitudinal studies are needed to better understand the associations between the use of antidepressants and mortality risk in dementia.List of scientific papersI. Kramberger MG, Jelic V, Kareholt I, Enache D, Eriksdotter Jönhagen M, Winblad B, Aarsland D. Cerebrospinal Fluid Alzheimer Markers in Depressed Elderly Subjects with and without Alzheimer's Disease. Dement Geriatr Cogn Dis Extra. 2012, 2:48-56. https://doi.org/10.1159/000334644 II. Enache D, Cavallin L, Lindberg O, Farahmand B, Kramberger MG, Westman E, Jelic V, Eriksdotter M, Ballard C, Winblad B, Wahlund L-O, Aarsland D. Medial Temporal Lobe Atrophy and Depressive Symptoms in Elderly Patients With and Without Alzheimer Disease. Journal of Geriatric Psychiatry and Neurology 2015, 28:40-8. https://doi.org/10.1177/0891988714541873 III. Enache D, Fereshtehnejad SM, Cermakova P, Garcia-Ptacek S, Kåreholt I, Johnell K, Religa D, Jelic V, Winblad B, Ballard C, Aarsland D, Fastbom J, Eriksdotter M. Antidepressants and mortality risk in a dementia cohort- data from SveDem, the Swedish Dementia Registry. [Submitted]IV. Enache D, Solomon A, Cavallin L, Kåreholt I, Kramberger MG, Aarslad D, Kivipelto M, Eriksdotter M, Winblad B, Jelic V. CAIDE Dementia Risk Score and biomarkers of neurodegeneration in memory clinic patients without dementia. [Submitted]</p
Characterization of Thin Film Photoanodes for Solar Water Splitting
No full textFor centuries, mankind has mostly used fossil fuels, i.e., natural gas, coal, and oil for its energy needs. With the fast rise of the world population and the rising standards of living in the developing countries, the amount of energy the world is going to need in the coming decades will grow enormously. Due to environmental concerns and the need to secure the energy supply, more actions have to be taken in the development and implementation of cleaner technologies, based on solar, wind, geothermal power, and biomass, combined with storage technologies such as batteries and hydrogen. Moreover, to fulfill the future global energy demand, all of the available energy sources will be needed. Despite the fact that solar energy is abundant, clean, and widely available, only a small percentage of this energy is utilized through conversion to electricity by photovoltaic systems. This is partly due to the need for smart technological inventions to make the alternative energy cost-effective and competitive with the conventional energy production. The Netherlands intends to increase the percentage of energy produced by sustainable sources from 4% nowadays to 20% in 2020. When considering sustainable energy production, also energy storage has to be investigated, since especially solar and wind energy are not continuous. In the chain of solar energy production and the need for energy storage, hydrogen is a promising storage candidate due to its high gravimetric energy density and its nonpollutive combustion product, water. Nowadays, hydrogen can be produced by a number of processes, such as electrolysis of water, steam reforming of natural gas, and biomass conversion, which directly or indirectly release large amounts of carbon dioxide into the atmosphere. An elegant alternative will be the use of solar energy for the electrolysis of water in a photoelectrochemical cell. Direct photoelectrolysis has the potential to be economically more attractive than coupled systems of photovoltaic cells and electrolysers. Additional information regarding this subject can be found in Chapter 1, as well as the necessary requirements for the photoelectrodes. In this thesis three different metal oxides, TiO2, InVO4, and Fe2O3 are investigated as photoanodes for water splitting applications. The aim of the research presented in this thesis is two-fold. First, the use of low-cost deposition techniques for the preparation of efficient thin-film photoanodes is explored. Special attention is given to the possibility to introduce dopants in a controlled manner. Second, the influence of the presence of ionic point defects on the photoelectrochemical performance of the materials is investigated. Titanium dioxide has long been considered as one of the most promising semiconductors for photoelectrolysis applications due to its low cost, non-toxicity, and excellent stability against corrosion. However, because of its wide bandgap (3.2 eV for anatase) the utilization of TiO2 typically remains confined to the UV light region, which constitutes only a small fraction (2-3%) of the solar radiation reaching the earth surface. Therefore, shifting its photoresponse into the visible range of the solar spectrum would enhance its potential for chemical solar energy conversion. Attempts to achieve this performance are typically focused on adding dopants. In Chapter 2 Fe- and C-doped TiO2 thin films have been investigated. Pulsed spray pyrolysis is employed to deposit high quality dense films. The prepared films are crystalline with an anatase structure and a post-deposition anneal does not change the morphology. For the Fe-doped TiO2 a small sub-bandgap photoresponse is observed, which is attributed to the presence of additional states located just above the valence band. Little or no visible-light photoresponse is observed for the C-doped anatase TiO2, which is attributed to a (too) low carbon content. However, the photocurrent at h?>Eg is significantly larger for C-doped TiO2 than for undoped TiO2. The strong enhancement of UV photoresponse is most likely caused by a change in the electronic structure of the material due to the presence of carbon and/or related defects. Photoluminescence measurements suggest that the defects present in oxidized carbon-doped anatase resemble those present in undoped, partially reduced TiO2. Although the exact nature of these defects is unknown, impedance measurements reveal a donor density of 1019-1020 cm-3 in C-doped TiO2. The high UV photoresponse is rather surprising for such a high donor density, and illustrates the intriguing, but still poorly understood properties of anion dopants. From the synthesis point of view, the preparation of carbon-doped TiO2 photoanodes was found to be challenging. A more simple approach is to prepare C-doped powders by solid-state reactions at high temperatures. Such a system can serve as a convenient screening method for selecting suitable anion dopants by analyzing the evolved gases, even if the efficiencies are very low. In Chapter 3 the focus is on the addition of carbon as dopant to anatase TiO2 by a post-deposition thermal treatment in a hexane-rich environment. Both thin films prepared by spray pyrolysis and mesoporous TiO2 photoelectrodes prepared by doctor-blading a paste of TiO2 nanoparticles are investigated. It is found that the carbon is mainly located at the surface of the TiO2. While it causes a black coloring of the mesoporous TiO2 film, it does not enhance the photocatalytic activity in the visible part of the spectrum. Only a small amount of carbon (3 and it has a near-optimal bandgap of 2.1 eV that enables up to 32% sunlight absorption. It is also an abundant and inexpensive semiconductor. However, certain intrinsic properties of Fe2O3 limit its performance as a photoelectrode. It shows a poor conductivity, which often leads to a high recombination rate, the energy level of the conduction band is too low for hydrogen evolution, it has slow kinetics for water oxidation, and a modest optical absorption coefficient. The main goal of the research in this chapter is on the preparation of Fe2O3 nanorods perpendicular to the substrate. Such a morphology could improve the efficiency of Fe2O3 photoanodes by decreasing the diffusion path length of the photo-generated holes. To achieve this, electrodeposition of Fe followed by thermal oxidation (EDOX) is explored as a new method to obtain these photoelectrodes efficiently in a short time and with the possibility to control the morphology. It is observed that after reaching a certain thickness or at a sufficiently high deposition current (2 mA/cm2) nano-sized needle- like features start to form. A further increase of the deposition current to 3 mA/cm2 results in a columnar growth consisting of small irregular crystallites stacked on top of each other. In contrast, it has been observed that when a Si precursor is present in the electrolyte solution during the electrodeposition, compact dense Fe2O3 films consisting of spherical particles are formed after the post-deposition oxidation. XRD analysis and Raman spectroscopy show that the Fe2O3 films mainly consist of the ?- Fe2O3 hematite phase. An important advantage of the EDOX method is that low-cost equipment can be used. Moreover, the direct thermal oxidation of electrodeposited Fe avoids the formation of undesired intermediate phases, such as FeOOH. Finally, the electrodeposition process takes place in a non-aqueous solvent, which allows the use of certain dopant precursors (e.g. TiCl4) that cannot be used in aqueous systems. This is an important advantage of this approach compared to other efforts in the literature. Although the EDOX method has been successfully demonstrated, an important remaining challenge is to improve control over the morphology and the doping density. Further improvements of the morphology may be possible by adding additives to the electrolyte solution, or by controlling the process parameters during oxidation of the electrodeposited iron. In conclusion, it has been demonstrated in this thesis that high-quality metal oxides can be prepared by low-cost techniques. Concomitantly, the impact of the ionic point defects on the performance of those photoanode materials is addressed and important material properties are determined. The attempts to enhance the visible-light response does not always result in higher efficiencies, due to low dopant concentrations in TiO2 films, poor electronic properties of InVO4 thin films, and morphology challenges for Fe2O3 to overcome its limitation as photoanode material. Nevertheless, important properties of the thin film photoanodes have been investigated and determined. No binary oxide solely can split water with a reasonable efficiency unless a tandem cell approach with suitable oxides is used. In principle, a lot can be gained by directing future research efforts towards ternary and even more complex metal oxides. In this case, however, the control over the stoichiometry of the metal ions remains challenging compared to simple binary oxides as has been demonstrated by the results on InVO4. While for some of the alternative energy sources technological breakthroughs have been achieved and new technologies are developed, for the hydrogen economy and in particular for the photoelectrochemical water splitting with metal oxides, more research is needed in developing low-cost techniques to make highly structured electrodes with large aspect ratios, to develop synthesis and/or doping strategies to suppress undesired defects present in the ternary oxides with non-stoichiometric metal:metal ratios, and not the least, in finding new and improving existing materials. When these challenges are met, photoelectrochemical water splitting may emerge as an economically viable and truly renewable pathway towards clean hydrogen.Materials for Energy Conversion and StorageApplied Science
Impact of physical exercise on parameters of arterial stiffness and wave intensity measured at carotid artery level
No full textCorrection to: Gastrointestinal ultrasonographic findings in cats with Feline panleukopenia: a case series (BMC Veterinary Research, (2021), 17, 1, (20), 10.1186/s12917-020-02720-w)
No full textAn amendment to this paper has been published and can be accessed via the original article
Final Report - Nutrient and ecological histories in Barnegat Bay, New Jersey
No full textThe report described a project to collect sediment cores from the tidal region of Barnegat Bay to determine the chronology of nutrient changes and associated ecosystem level responses
Gastrointestinal ultrasonographic findings in cats with Feline panleukopenia: a case series
No full textBackground: Feline panleukopenia virus (FPV) is very resistant and highly contagious and infects domestic cats and other felids. FPV is particularly widespread among sheltered cats, and is associated with high morbidity and mortality, causing severe gastroenteritis characterized by anorexia, lethargy, fever, dehydration, hemorrhagic diarrhea, and vomiting. There is currently no data on the ultrasonographic features of cats affected with FPV. This case series describes abdominal ultrasonographic findings in shelter cats with naturally-occurring FPV, and assesses whether are associated with clinical and laboratory findings. Cats affected by FPV were enrolled in the study if an abdominal ultrasound was performed within 12 hours of diagnosis. Clinical, laboratory and survival data were collected from medical records. Ultrasonographic examinations were reviewed for gastrointestinal abnormalities and their associations with the above data were explored. Results: Twenty-one cats were included. Nine cats (42.9%) died and 12 (57.1%) recovered. Based on ultrasonography, the duodenum and jejunum showed thinning of the mucosal layer in 70.6% and 66.6% of cats, thickening of the muscular layer in 52.9% and 57.1% of cats, and hyperechogenicity of the mucosa in 41.2% and 33.3%. Jejunal hyperechoic mucosal band paralleling the submucosa and irregular luminal surface were both observed in 33.3% of the cats. Survival was positively associated with increased jejunal mucosal echogenicity (P = 0.003) and hyperechoic mucosal band (P = 0.003). Peritoneal free fluid was positively associated with vomiting (P = 0.002). Conclusions: This study provides ultrasonographic features of naturally-occurring FPV in cats, which, as expected, are compatible with gastroenteropathy. The most frequent findings were diffuse small intestine mucosal layer thinning, muscular layer thickening and mucosal hyperechogenicity, jejunal hyperechoic mucosal band and irregular luminal surface. Ultrasonographic features may be useful to complete the clinical picture and assess the severity of the gastroenteropathy in FPV cats. Prospective studies are needed to confirm ultrasonographic prognostic factors
Slow Conduction Corridors and Pivot Sites Characterize the Electrical Remodeling in Atrial Fibrillation
No full textObjectives: This study aimed to evaluate the progression of electrophysiological phenomena in a cohort of patients with paroxysmal atrial fibrillation (PAF) and persistent atrial fibrillation (PsAF). Background: Electrical remodeling has been conjectured to determine atrial fibrillation (AF) progression. Methods: High-density electroanatomic maps during sinus rhythm of 20 patients with AF (10 PAF, 10 PsAF) were compared with 5 healthy control subjects (subjects undergoing ablation of a left-sided accessory pathway). A computational postprocessing of electroanatomic maps was performed to identify specific electrophysiological phenomena: slow conductions corridors, defined as discrete areas of conduction velocity <50 cm/s, and pivot points, defined as sites showing high wave-front curvature documented by a curl module >2.5 1/s. Results: A progressive decrease of mean conduction velocity was recorded across the groups (111.6 ± 55.5 cm/s control subjects, 97.1 ± 56.3 cm/s PAF, and 84.7 ± 55.7 cm/s PsAF). The number and density of slow conduction corridors increase in parallel with the progression of AF (8.6 ± 2.2 control subjects, 13.3 ± 3.2 PAF, and 20.5 ± 4.5 PsAF). In PsAF the atrial substrate is characterized by a higher curvature of wave-front propagation (0.86 ± 0.71 1/s PsAF vs 0.74 ± 0.63 1/s PAF; P = 0.003) and higher number of pivot points (25.1 ± 13.8 PsAF vs 9.5 ± 6.7 PAF; P < 0.0001). Slow conductions: corridors were mostly associated with pivot sites tending to cluster around pulmonary veins antra. Conclusions: The electrical remodeling hinges mainly on corridors of slow conduction and higher curvature of wave-front propagation. Pivot points associated to SC corridors may be the major determinants for functional localized re-entrant circuits creating the substrate for maintenance of AF
The typology of human constitutions in Hippocrates’ De victu 1, 32. Wiener Studien|Wiener Studien 124 124|
No full textThe paper offers an interpretation of a rather intriguing chapter of the Hippocratic treatise De victu. The author argues that the human constitutions described in De victu 1, 32 are to be regarded in the metaphysical and anthropological context of Book I of the treatise, according to which everything can be reduced to two elements (fire and water) and four properties (warm, dry, cold, wet)
Part II. Drama / Choreography5. Theater Dance Atelier
No full textThe substance of the spiritual and cultural life is the syncretism of the arts from the performer-spectator division, that was made concurrently with the “dance” segmentation into work and pleasure. Words were held in formulas, gestures and dance in rhythm. Today, dance is mostly seen as the art of gesture. However, it is remarkable to reflect at to what extent the dance, as an organic necessity, it could further develop into hermetic structures that would still require analyses and studies from researchers in the field. In today‟s theatrical landscape, this formula of artistic expression which was called theatre dance evolved so much so that gesticulations and body exploration became its core components
Character, voice and the limits of dietetics in Hippocrates’ De victu I 36. Wiener Studien|Wiener Studien 129 129|
No full textIn this paper I mainly deal with two questions. Firstly, I examine the human characteristics that cannot be influenced by regimen as presented in ch. I 36 of De victu and especially the reasons why the Hippocratic author placed them outside the reach of dietetics; within this inquiry I will make an excursus on the theory of perception in ch. I 35. Secondly, I analyse the text of the voice analogy and offer an interpretation that suits the author’s intention
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