Exploitation of a pH-sensitive hydrogel for CO2 detection

In this paper is described how hydrogel is exploited as sensor material for the \ud detection of carbon dioxide (CO2). A pH-sensitive hydrogel disc, which swells and deswells in response to pH changes, was clamped between a pressure sensor membrane and a porous metal screen together with a bicarbonate solution. Bicarbonate reacts with CO2 resulting in a pH change. The enclosed hydrogel will generate pressure as a response to the pH change. This pressure is a measure for the partial pressure of CO2. The main advantage of this sensor principle is the lack of a reference electrode as required for potentiometric sensors

A micro CO2 gas sensor based on sensing of pH-sensitive hydrogel swelling by means of a pressure sensor

In this paper a sensor is presented for the detection of carbon dioxide gas inside the stomach in order to diagnose gastrointestinal ischemia. The operational principle of the sensor is measuring the CO/sub 2/ induced pressure generation of a confined pH-sensitive hydrogel by means of a micro pressure sensor. The sensor is capable of measuring CO/sub 2/ with a response time between 2 and 4 minutes and a maximum pressure of 0.29/spl times/10/sup 5/ Pa at 20 kPa CO/sub 2/. The sensor is able to resist up to 1 M HCl acid as can be present inside the stomach. The results are very promising for real application and clinical trials are planned

A preliminary phylogeographic study of Flavopunctelia and Punctelia inferred from rDNA ITS-sequences

A preliminary phylogeny of the genera Flavopunctelia and Punctelia is presented. Genus and species delimitations have been investigated using ITS rDNA-sequencing of populations from different continents. Current genus delimitations of Flavopunctelia, Punctelia and Parmelia are confirmed and the species status of recently resurrected Punctelia ulophylla is confirmed. The status of three cryptic species, Flavopunctelia soredica, Punctelia perreticulata and P. stictica is discussed. Flavopunctelia borrerioides and Punctelia perreticulata are reported from China for the first time.Esitatakse perekondade Flavopunctelia ja Punctelia esialgne fülogeneesi rekonstruktsioon. Perekondade ja liikide eraldamist on uuritud erinevatelt kontinentidelt pärinevate populatsioonide ITS rDNA sekventside alusel. Senine perekondade Flavopunctelia, Punctelia ja Parmelia piiritlemine on leidnud kinnitust, samuti liigi Punctelia ulophylla staatus. Arutletakse kolme krüptilise liigi, Flavopunctelia soredica, Punctelia perreticulata ja P. stictica staatuse üle. Teatatakse liikide Flavopunctelia borrerioides ja Punctelia perreticulata esmasleidudest HiinasFil: Thell, Arne. Lund University; SueciaFil: Herber, B.. Universitat Hamburg; AlemaniaFil: Aptroot, A.. Centraalbureau voor Schimmelcultures; Países BajosFil: Adler, Monica Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Feuerer, T.. Universitat Hamburg; AlemaniaFil: Kärnefelt, Ingvar. Lund University; Sueci

What the guide does not tell you: reflections on and lessons learned from applying the COM-B behavior model for designing real life interventions

Substantial inconsistency exists in the effectiveness of existing interventions to improve heart failure (HF) self-care, which can be partially explained by the fact that self-management interventions often lack theoretical models that underpin intervention development. The COM-B behavior model is a comprehensive theoretical framework that can be used to develop effective, theory-based interventions. The aim of this article is to highlight the challenges and practical solutions when applying the COM-B model to HF self-care, in order to provide useful support for researchers intending to use the model for designing behavior change interventions. “The Behaviour Change Wheel” handbook provides a step-by-step guide to understand and change behavior. When following the guide, some practical and methodological challenges were encountered. Lessons learnt to overcome these challenges are reported. Although the handbook is a comprehensive guide for designing behavior change interventions, a number of challenges arose. For example, the descriptions provided in the guide were not always sufficient to make solid judgments on how to categorize determinants; narrowing down intervention possibilities to a manageable number and prioritizing potential behavior change techniques over others involved a certain amount of subjectivity in an otherwise highly systematic and structured approach. For the encountered challenges, solutions are provided to illustrate how the model was applied practically to design theory-based behavior change interventions. This article provides a useful reference for researchers’ use of the COM-B behavior model, as it outlines challenges that may occur and potential solutions to overcome them

Dysregulation of Na+/K+ ATPase by amyloid in APP+PS1 transgenic mice

BACKGROUND: The pathology of Alzheimer's disease (AD) is comprised of extracellular amyloid plaques, intracellular tau tangles, dystrophic neurites and neurodegeneration. The mechanisms by which these various pathological features arise are under intense investigation. Here, expanding upon pilot gene expression studies, we have further analyzed the relationship between Na+/K+ ATPase and amyloid using APP+PS1 transgenic mice, a model that develops amyloid plaques and memory deficits in the absence of tangle formation and neuronal or synaptic loss. RESULTS: We report that in addition to decreased mRNA expression, there was decreased overall Na+/K+ ATPase enzyme activity in the amyloid-containing hippocampi of the APP+PS1 mice (although not in the amyloid-free cerebellum). In addition, dual immunolabeling revealed an absence of Na+/K+ ATPase staining in a zone surrounding congophilic plaques that was occupied by dystrophic neurites. We also demonstrate that cerebral Na+/K+ ATPase activity can be directly inhibited by high concentrations of soluble Aβ. CONCLUSIONS: The data suggest that the reductions in Na+/K+ ATPase activity in Alzheimer tissue may not be purely secondary to neuronal loss, but may results from direct effects of amyloid on this enzyme. This disruption of ion homeostasis and osmotic balance may interfere with normal electrotonic properties of dendrites, blocking intraneuronal signal processing, and contribute to neuritic dystrophia. These results suggest that therapies aimed at enhancing Na+/K+ ATPase activity in AD may improve symptoms and/or delay disease progression

SFTA2 - a novel secretory peptide highly expressed in the lung - is modulated by lipopolysaccharide but not hyperoxia

Tissue-specific transcripts are likely to be of importance for the corresponding organ. While attempting to define the specific transcriptome of the human lung, we identified the transcript of a yet uncharacterized protein, SFTA2. In silico analyses, biochemical methods, fluorescence imaging and animal challenge experiments were employed to characterize SFTA2. Human SFTA2 is located on Chr. 6p21.33, a disease-susceptibility locus for diffuse panbronchiolitis. RT-PCR verified the abundance of SFTA2-specific transcripts in human and mouse lung. SFTA2 is synthesized as a hydrophilic precursor releasing a 59 amino acid mature peptide after cleavage of an N-terminal secretory signal. SFTA2 has no recognizable homology to other proteins while orthologues are present in all mammals. SFTA2 is a glycosylated protein and specifically expressed in nonciliated bronchiolar epithelium and type II pneumocytes. In accordance with other hydrophilic surfactant proteins, SFTA2 did not colocalize with lamellar bodies but colocalized with golgin97 and clathrin-labelled vesicles, suggesting a classical secretory pathway for its expression and secretion. In the mouse lung, Sfta2 was significantly downregulated after induction of an inflammatory reaction by intratracheal lipopolysaccharides paralleling surfactant proteins B and C but not D. Hyperoxia, however, did not alter SFTA2 mRNA levels. We have characterized SFTA2 and present it as a novel unique secretory peptide highly expressed in the lung

Imaging an Adapted Dentoalveolar Complex

Adaptation of a rat dentoalveolar complex was illustrated using various imaging modalities. Micro-X-ray computed tomography for 3D modeling, combined with complementary techniques, including image processing, scanning electron microscopy, fluorochrome labeling, conventional histology (H&E, TRAP), and immunohistochemistry (RANKL, OPN) elucidated the dynamic nature of bone, the periodontal ligament-space, and cementum in the rat periodontium. Tomography and electron microscopy illustrated structural adaptation of calcified tissues at a higher resolution. Ongoing biomineralization was analyzed using fluorochrome labeling, and by evaluating attenuation profiles using virtual sections from 3D tomographies. Osteoclastic distribution as a function of anatomical location was illustrated by combining histology, immunohistochemistry, and tomography. While tomography and SEM provided past resorption-related events, future adaptive changes were deduced by identifying matrix biomolecules using immunohistochemistry. Thus, a dynamic picture of the dentoalveolar complex in rats was illustrated

Ground-based lidar measurements from Ny-Ålesund during ASTAR 2007

During the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) in March and April 2007, measurements obtained at the AWIPEV Arctic Research Base in Ny-Ålesund, Spitsbergen at 78.9° N, 11.9° E (operated by the Alfred Wegener Institute for Polar and Marine Research – AWI and the Institut polaire français Paul-Emile Victor – IPEV), supported the airborne campaign. This included lidar data from the Koldewey Aerosol Raman Lidar (KARL) and the Micro Pulse Lidar (MPL), located in the atmospheric observatory as well as photometer data and the daily launched radiosonde. The MPL features nearly continuous measurements; the KARL was switched on whenever weather conditions allowed observations (145 h in 61 days). From 1 March to 30 April, 71 meteorological balloon soundings were performed and compared with the concurrent MPL measurements; photometer measurements are available from 18 March. For the KARL data, a statistical overview of particle detection based on their optical properties backscatter ratio and volume depolarization can be given. The altitudes of the occurrence of the named features (subvisible and visible ice and water as well as mixed-phase clouds, aerosol layers) as well as their dependence on different air mass origins are analyzed. Although the spring 2007 was characterized by rather clean conditions, diverse case studies of cloud and aerosol occurrence during March and April 2007 are presented in more detail, including temporal development and main optical properties as depolarization, backscatter and extinction coefficients. Links between air mass origins and optical properties can be presumed but need further evidence

Optical thickness and effective radius of Arctic boundary-layer clouds retrieved from airborne nadir and imaging spectrometry

Arctic boundary-layer clouds in the vicinity of Svalbard (78° N, 15° E) were observed with airborne remote sensing and in situ methods. The cloud optical thickness and the droplet effective radius are retrieved from spectral radiance data from the nadir spot (1.5°, 350–2100 nm) and from a nadir-centred image (40°, 400–1000 nm). Two approaches are used for the nadir retrieval, combining the signal from either two or five wavelengths. Two wavelengths are found to be sufficient for an accurate retrieval of the cloud optical thickness, while the retrieval of droplet effective radius is more sensitive to the number of wavelengths. Even with the comparison to in-situ data, it is not possible to definitely answer the question which method is better. This is due to unavoidable time delays between the in-situ measurements and the remote-sensing observations, and to the scarcity of vertical in-situ profiles within the cloud