2,153 research outputs found

    Synthesis of heterocyclic annulated quinones and quinoid compounds

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    Sound attenuation in the ear of domestic chickens (Gallus gallus domesticus) as a result of beak opening

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    Because the quadrate and the eardrum are connected, the hypothesis was tested that birds attenuate the transmission of sound through their ears by opening the bill, which potentially serves as an additional protective mechanism for self-generated vocalizations. In domestic chickens, it was examined if a difference exists between hens and roosters, given the difference in vocalization capacity between the sexes. To test the hypothesis, vibrations of the columellar footplate were measured ex vivo with laser Doppler vibrometry (LDV) for closed and maximally opened beak conditions, with sounds introduced at the ear canal. The average attenuation was 3.5 dB in roosters and only 0.5 dB in hens. To demonstrate the importance of a putative protective mechanism, audio recordings were performed of a crowing rooster. Sound pressures levels of 133.5 dB were recorded near the ears. The frequency content of the vocalizations was in accordance with the range of highest hearing sensitivity in chickens. The results indicate a small but significant difference in sound attenuation between hens and roosters. However, the amount of attenuation as measured in the experiments on both hens and roosters is small and will provide little effective protection in addition to other mechanisms such as stapedius muscle activity

    Deformation of avian middle ear structures under static pressure loads, and potential regulation mechanisms

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    Static pressure changes can alter the configuration and mechanical behavior of the chain of ossicles, which may affect the acoustic transfer function. In mammals, the Eustachian tube plays an important role in restoring ambient middle ear pressure, hence restoring the acoustic transfer function and excluding barotrauma of the middle and inner ear. Ambient pressure fluctuations can be potentially extreme in birds and due to the simple structure of the avian middle ear (one ossicle, one muscle), regulation of the middle ear pressure via reflexive opening of the pharyngotympanic tube appears all the more important. In this study the deformations of the chicken (Gallus gallus domesticus) middle ear structures, as a result of middle ear pressure alterations, are quantified, using micro-CT scanning. It was experimentally tested whether reflexive opening of the pharyngotympanic tube to restore ambient middle ear pressure is present in chicken and mallard (Anas platyrhynchos) and whether this mechanism depends on sensing middle ear pressure indirectly via deformations of the middle ear components or sensing the middle ear pressure directly. A translation of the columella footplate was observed when middle ear pressure was kept at 1 kPa and -1 kPa relative to ambient pressure. Deformation of the tympanic membrane was larger than the columella footplate translation. Bending and deformation of the extracolumella was observed. Opening of the pharyngotympanic tube occurred at random pressure for both chicken and mallard when middle ear pressure was raised and lowered by 1.5 kPa relative to ambient pressure. We also did not find a difference in middle ear venting rate when middle ear pressure was held constant at 0.5, 1, 1.5, -0.5, -1 and -1.5 kPa for chickens and at 1, 2, 4, -1, -2 and -4 kPa for mallards. As a result, no statement can be made about pressure within the avian middle ear being measured directly or indirectly. Our experiments do not support the presence of a short-loop reflexive control of pressure equilibration via the pharyngotympanic tube. However, it is still possible that triggering this loop requires additional sensorial input (e.g. visual, vestibular) or that it occurs voluntarily (being controlled at a higher brain level)

    Town of Lisbon, Maine Annual Financial Report For The Fiscal Year Ended June 30, 2012

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    Serum p-cresyl sulfate (PCS) associates with cardiovascular disease in patients with chronic kidney disease. PCS concentrations are determined by intestinal uptake of p-cresol, human metabolism to PCS and renal clearance. Whether intestinal uptake of p-cresol itself is directly associated with cardiovascular disease in patients with renal dysfunction has not been studied to date.status: publishe

    Mycophenolate mofetil in IgA nephropathy: Results of a 3-year prospective placebo-controlled randomized study

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    Mycophenolate mofetil in IgA nephropathy: Results of a 3-year prospective placebo-controlled randomized study.BackgroundBecause humoral immunity is believed to play a pivotal role in the pathogenesis of IgA nephropathy (IgAN), a prospective placebo-controlled randomized study was started in patients with IgAN using mycophenolate mofetil (MMF).MethodsA total of 34 patients with IgAN were treated with salt intake restriction, angiotensin-converting enzyme (ACE) inhibition and MMF 2g per day (N = 21) or placebo (N = 13). After 36months of follow-up clinical, biochemical, and radiologic data were analyzed using linear mixed models for longitudinal data and Kaplan-Meier survival analysis.ResultsTherapy had to be stopped prematurely in five patients. Two patients (MMF group) evolved to end-stage renal disease (ESRD). There was no difference between groups in the percentage of patients with a decrease of 25% or more in the inulin clearance or with a serum creatinine increase of 50% or more over 3years. There was also no significant difference between groups in annualized rate of change of serum creatinine, computed by linear regression analysis. No significant difference was noted between groups for inulin clearance, serum creatinine, proteinuria, blood pressure, or other parameters of renal function. Hemoglobin and C-reactive protein were significantly lower in the MMF group compared with the placebo group. As a function of time, a significant decline in both groups was noted of proteinuria, parenchymal thickness of the kidneys and C3d.ConclusionIn patients with IgAN at risk for progressive disease, no beneficial effect of 3-year treatment with MMF 2g per day could be demonstrated on renal function/outcome or proteinuria. However, larger randomized studies are needed to confirm or reject these results

    Effects of Dual Targeting of Tumor Cells and Stroma in Human Glioblastoma Xenografts with a Tyrosine Kinase Inhibitor against c-MET and VEGFR2

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    Contains fulltext : 118357.pdf (publisher's version ) (Open Access)Anti-angiogenic treatment of glioblastoma with Vascular Endothelial Growth Factor (VEGF)- or VEGF Receptor 2 (VEGFR2) inhibitors normalizes tumor vessels, resulting in a profound radiologic response and improved quality of life. This approach however does not halt tumor progression by diffuse infiltration, as this phenotype is less angiogenesis dependent. Combined inhibition of angiogenesis and diffuse infiltrative growth would therefore be a more effective treatment approach in these tumors. The HGF/c-MET axis is important in both angiogenesis and cell migration in several tumor types including glioma. We therefore analyzed the effects of the c-MET- and VEGFR2 tyrosine kinase inhibitor cabozantinib (XL184, Exelixis) on c-MET positive orthotopic E98 glioblastoma xenografts, which routinely present with angiogenesis-dependent areas of tumor growth, as well as diffuse infiltrative growth. In cultures of E98 cells, cabozantinib effectively inhibited c-MET phosphorylation, concomitant with inhibitory effects on AKT and ERK1/2 phosphorylation, and cell proliferation and migration. VEGFR2 activation in endothelial cells was also effectively inhibited . Treatment of BALB/c nu/nu mice carrying orthotopic E98 xenografts resulted in a significant increase in overall survival. Cabozantinib effectively inhibited angiogenesis, resulting in increased hypoxia in angiogenesis-dependent tumor areas, and induced vessel normalization. Yet, tumors ultimately escaped cabozantinib therapy by diffuse infiltrative outgrowth via vessel co-option. Of importance, in contrast to the results from experiments, blockade of c-MET activation was incomplete, possibly due to multiple factors including restoration of the blood-brain barrier resulting from cabozantinib-induced VEGFR2 inhibition. In conclusion, cabozantinib is a promising therapy for c-MET positive glioma, but improving delivery of the drug to the tumor and/or the surrounding tissue may be needed for full activity

    Multiscale approach to (micro)porosity quantification in continental spring carbonate facies: Case study from the Cakmak quarry (Denizli, Turkey)

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    Carbonate spring deposits gained renewed interest as potential contributors to subsurface reservoirs and as continental archives of environmental changes. In contrast to their fabrics, petrophysical characteristics – and especially the importance of microporosity (< 1µm) – are less understood. This study presents the combination of advanced petrophysical and imaging techniques to investigate the pore network characteristics of three, common and widespread spring carbonate facies, as exposed in the Pleistocene Cakmak quarry (Denizli, Turkey): the extended Pond, the dipping crystalline Proximal Slope Facies and the draping Apron and Channel Facies deposits formed by encrustation of biological substrate. Integrating mercury injection capillary pressure, bulk and diffusion Nuclear Magnetic Resonance (NMR), NMR profiling and Brunauer–Emmett–Teller (BET) measurements with microscopy and micro-computer tomography (µ-CT), shows that NMR T2 distributions systematically display a single group of micro-sized pore bodies, making up between 6 and 33% of the pore space (average NMR T2 cut-off value: 62 ms). Micropore bodies are systematically located within cloudy crystal cores of granular and dendritic crystal textures in all facies. The investigated properties therefore do not reveal differences in micropore size or shape with respect to more or less biology-associated facies. The pore network of the travertine facies is distinctive in terms of (i) the percentage of microporosity, (ii) the connectivity of micropores with meso- to macropores, and (ii) the degree of heterogeneity at micro- and macroscale. Results show that an approach involving different NMR experiments provided the most complete view on the 3-D pore network especially when microporosity and connectivity are of interest

    Multiscale approach to (micro)porosity quantification in continental spring carbonate facies: Case study from the Cakmak quarry (Denizli, Turkey)

    Get PDF
    Carbonate spring deposits gained renewed interest as potential contributors to subsurface reservoirs and as continental archives of environmental changes. In contrast to their fabrics, petrophysical characteristics – and especially the importance of microporosity (< 1µm) – are less understood. This study presents the combination of advanced petrophysical and imaging techniques to investigate the pore network characteristics of three, common and widespread spring carbonate facies, as exposed in the Pleistocene Cakmak quarry (Denizli, Turkey): the extended Pond, the dipping crystalline Proximal Slope Facies and the draping Apron and Channel Facies deposits formed by encrustation of biological substrate. Integrating mercury injection capillary pressure, bulk and diffusion Nuclear Magnetic Resonance (NMR), NMR profiling and Brunauer–Emmett–Teller (BET) measurements with microscopy and micro-computer tomography (µ-CT), shows that NMR T2 distributions systematically display a single group of micro-sized pore bodies, making up between 6 and 33% of the pore space (average NMR T2 cut-off value: 62 ms). Micropore bodies are systematically located within cloudy crystal cores of granular and dendritic crystal textures in all facies. The investigated properties therefore do not reveal differences in micropore size or shape with respect to more or less biology-associated facies. The pore network of the travertine facies is distinctive in terms of (i) the percentage of microporosity, (ii) the connectivity of micropores with meso- to macropores, and (ii) the degree of heterogeneity at micro- and macroscale. Results show that an approach involving different NMR experiments provided the most complete view on the 3-D pore network especially when microporosity and connectivity are of interest

    A mutation update for the FLNC gene in myopathies and cardiomyopathies

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    Filamin C (FLNC) variants are associated with cardiac and muscular phenotypes. Originally, FLNC variants were described in myofibrillar myopathy (MFM) patients. Later, high-throughput screening in cardiomyopathy cohorts determined a prominent role for FLNC in isolated hypertrophic and dilated cardiomyopathies (HCM and DCM). FLNC variants are now among the more prevalent causes of genetic DCM. FLNC-associated DCM is associated with a malignant clinical course and a high risk of sudden cardiac death. The clinical spectrum of FLNC suggests different pathomechanisms related to variant types and their location in the gene. The appropriate functioning of FLNC is crucial for structural integrity and cell signaling of the sarcomere. The secondary protein structure of FLNC is critical to ensure this function. Truncating variants with subsequent haploinsufficiency are associated with DCM and cardiac arrhythmias. Interference with the dimerization and folding of the protein leads to aggregate formation detrimental for muscle function, as found in HCM and MFM. Variants associated with HCM are predominantly missense variants, which cluster in the ROD2 domain. This domain is important for binding to the sarcomere and to ensure appropriate cell signaling. We here review FLNC genotype–phenotype correlations based on available evidence
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