239 research outputs found
Vorticella bosminae Sramek-Husek 1948
No full textVorticella bosminae Sramek-Husek, 1948 Known Distribution. Czech Republic, and The Netherlands. Hosts. Bosmina (Bosmina) longirostris cited as Bosmina longirostris; Mesocyclops leuckarti; Thermocyclops hyalinus (cited as Thermocyclopsis hyalinus); cyclopoid copepods. References. Green 1974; Warren 1986; Morado & Small 1995; Fernandez-Leborans & Tato-Porto 2000; Chatterjee et al. 2013.Published as part of Mayén-Estrada, Rosaura & Pinto Utz, Laura R., 2018, A checklist of species of Vorticellidae (Ciliophora: Peritrichia) epibionts of crustaceans, pp. 301-328 in Zootaxa 4500 (3) on page 311, DOI: 10.11646/zootaxa.4500.3.1, http://zenodo.org/record/529765
The influence of extravascular lung water on cardiac output measurements using thoracic impedance cardiography
No full textThe purpose of this study was to investigate the influence of pulmonary oedema as measured with the double indicator dilution technique on the accuracy of cardiac output (CO) measurement using thoracic impedance cardiography (TIC) compared with thermodilution in thirteen sepsis patients. Differences in the Kubicek and Sramek-Bernstein equation with respect to pulmonary oedema were explored theoretically and experimentally. From a parallel two cylinder model a hypothesis can be derived that CO determined with the Kubicek equation is oedema independent, whereas CO determined using the Sramek-Bernstein equation is oedema dependent. Experimentally, CO determined using Kubicek's equation correlated better with thermodilution CO (r = 0.75) than CO determined with the Sramek-Bernstein equation (r = 0.25). The effect of oedema on the accuracy of TIC was investigated by comparing the differences in the CO of impedance and thermodilution to the extravascular lung water index. For the Kubicek equation the difference was not influenced by oedema (r = 0.04, p = 0.84), whereas for the Sramek-Bernstein equation the difference was affected by oedema (r = 0.39, p = 0.05). Thus, the effects of pulmonary oedema on the accuracy of TIC measurements can better be understood with the parallel cylinder model. Moreover, the Kubicek equation still holds when pulmonary oedema is present, in contrast to the Sramek-Bernstein equatio
The influence of weight on stroke volume determination by means of impedance cardiography in cardiac surgery patients
No full textOBJECTIVES: Obesity is thought to be one of the conditions in which the impedance cardiographic method is less reliable for estimating stroke volume (SV). This led to the introduction of a weight correction factor, sigma, into the equation according to Sramek and Bernstein. However, no scientific evidence has been published to support the use of this factor. The objectives of the present study are to evaluate the influence of body weight on the accuracy of impedance cardiography and to validate Bernstein's weight correction factor by comparison with thermodilution in patients after coronary bypass surgery. DESIGN: Prospective clinical study. SETTING: A surgical intensive care unit in a university hospital. PATIENTS: 37 consecutive patients 24-36 h after coronary bypass surgery, sub-divided into a normal-weight group (n = 24), patients whose weight deviated less than 15% from their ideal weight, and an obese group (n = 13), patients whose weight deviated more than 15% from their ideal weight. MEASUREMENTS: Kubicek's impedance cardiographic method and Sramek and Bernstein's method to assess SV are applied and compared to thermodilution. In order to study the validity of sigma, the results are compared between 24 patients with normal weight and 13 obese patients. RESULTS: A significant correlation between miscalculation of SV by impedance cardiography and the degree of obesity for Sramek and Bernstein's method is found when sigma is not included in the equation (r = -0.55, p < 0.05). This relation, however, remained significant when sigma was included in the equation (r = -0.40, p < 0.05). Kubicek's method shows no significant correlation for this relation (r = -0.30). Besides this, Sramek and Bernstein's method underestimates SV significantly in the obese group, independent of the use of sigma in the equation. These results are explained as being intrinsic to the equation, according to Sramek and Bernstein. In the whole group the impedance-derived SV did not significantly differ from SV as measured by means of thermodilution, independent of the method used to calculate SV. However, a considerably better correlation and agreement (mean difference +/- 2 standard deviations is found when Kubicek's method is applied (r = 0.90, 0.5 +/- 17.1 ml vs 0.64, -4.9 +/- 31.8 ml for Sramek and Bernstein's method). CONCLUSIONS: Weight significantly influences Sramek and Bernstein's method of impedance cardiography, whereas Kubicek's method is not biased by this factor
Crack Drill Squad
No full textCrack Drill Squad: Lawrence Carlsen, Manny Goldberg, R. Solt, Jude Weith, William Foral, Keith Hey, Hector Vesty, Donald Rynes. Richard Vincent, Peter Lootens, Thomas Higgins, Paul Lamb, Gordon Rips, Paul Blatz, Edward O'Grady, Dennis Gainey, Thomas Hazzard, Eugene Sramek
Standardization of non-invasive impedance cardiography for assessment of stroke volume: comparison with thermodilution
No full textSince its introduction by Kubicek and colleagues, impedance cardiography has been suggested as a non-invasive, simple, safe and cost-effective method of measuring stroke volume. Several controversial reports on its validity have been published. Pitfalls of this method included the nature of the electrode system and the validity of the equations. Therefore, the purpose of this study was to compare two different spot electrode arrays and the two most frequently used stroke volume equations with each other and with thermodilution. In 37 patients, 24-36 h after cardiac surgery, we performed simultaneous measurements of stroke volume with impedance cardiography (SVIC) and with thermodilution (SVTD). SVIC was obtained using the lateral spot (LS) electrode array, according to Bernstein, and a newly proposed modified semi-circular (MSC) spot electrode array. The equations of Kubicek and Sramek-Bernstein were used to calculate SVIC. The Sramek-Bernstein equation was valid only when the LS array was used; the Kubicek equation determined SVTD correctly only when the MSC array was used. However, a considerably better correlation and agreement (mean difference (2 SD)) was found between SVIC and SVTD for the latter (r = 0.90, 0.5 (17.1) ml vs r = 0.64, -4.9 (31.8) ml for the Sramek-Bernstein equation). We conclude that the most valid measurement of stroke volume using impedance cardiography was obtained when the MSC array was used together with Kubicek's equation
CaM kinase II regulates cardiac hemoglobin expression through histone phosphorylation upon sympathetic activation
No full textSignificance Posttranslational modifications of the histone 3 (H3) tail in response to stress represent highly conserved epigenetic processes. However, the regulatory function of histone phosphorylation has hardly been studied in postmitotic cardiomyocytes. Here, we identified CaMKII as a catecholamine-sensitive kinase phosphorylating H3S28. We identified CaMKII-dependent H3S28p-regulated genes including hemoglobin, pointing to a previously unrecognized role of CaMKII for cardiac hemoglobin homeostasis. This study raises fundamental questions about the role of hemoglobin in nonhematopoietic cells such as cardiomyocytes and about the role of CaMKII for hematopoesis.Sympathetic activation of β-adrenoreceptors (β-AR) represents a hallmark in the development of heart failure (HF). However, little is known about the underlying mechanisms of gene regulation. In human ventricular myocardium from patients with end-stage HF, we found high levels of phosphorylated histone 3 at serine-28 (H3S28p). H3S28p was increased by inhibition of the catecholamine-sensitive protein phosphatase 1 and decreased by β-blocker pretreatment. By a series of in vitro and in vivo experiments, we show that the β-AR downstream protein kinase CaM kinase II (CaMKII) directly binds and phosphorylates H3S28. Whereas, in CaMKII-deficient myocytes, acute catecholaminergic stimulation resulted in some degree of H3S28p, sustained catecholaminergic stimulation almost entirely failed to induce H3S28p. Genome-wide analysis of CaMKII-mediated H3S28p in response to chronic β-AR stress by chromatin immunoprecipitation followed by massive genomic sequencing led to the identification of CaMKII-dependent H3S28p target genes. Forty percent of differentially H3S28p-enriched genomic regions were associated with differential, mostly increased expression of the nearest genes, pointing to CaMKII-dependent H3S28p as an activating histone mark. Remarkably, the adult hemoglobin genes showed an H3S28p enrichment close to their transcriptional start or end sites, which was associated with increased messenger RNA and protein expression. In summary, we demonstrate that chronic β-AR activation leads to CaMKII-mediated H3S28p in cardiomyocytes. Thus, H3S28p-dependent changes may play an unexpected role for cardiac hemoglobin regulation in the context of sympathetic activation. These data also imply that CaMKII may be a yet unrecognized stress-responsive regulator of hematopoesis
The Brightness Distribution of Core-Halo Radio Sources
No full textNOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.
The east-west visibility of 28 extragalactic radio sources with both large and very small components was obtained at 605 MHz using the radio interferometer at the Owens Valley Radio Observatory. A 2' HPBW fan beam was synthesized from observations made at twelve spacings between 62 and 977 wavelengths. The availability of such low spatial frequencies permitted the calculation of the brightness distribution of components as large as 56'. The brightness distributions of the following galaxies are plotted: (spiral galaxies) P0045-25, P1302-49 P1334-29, (elliptical galaxies) 3C40, 3C105, P0843-33, 3C236, 3C247, 3C264, P1216-10, 3C274, 3C287.1, 3C293, and P2247+11.
Fourteen of the observed sources had a core-halo or asymmetric double structure and had their large components well resolved at the 977[...] spacing. The spectral indices of the large and small components of these sources were obtained by comparing the flux densities given here with those at other frequencies. The spectra of the large components are generally steeper than those of the small components with an average difference of spectral indices of [...] = +0.3.
Assuming equipartition of magnetic and particle energies the total energies of the large halos are ~ [...] ergs. This is sufficient energy to maintain the current radio luminosities for ~ [...] years.
Three of these fourteen sources have a core-halo structure and are associated with spiral galaxies; the remaining eleven are associated with elliptical galaxies. Two of the remaining sources are asymmetric doubles, and nine have a core-halo structure. Four of the core-halo sources have simple halos, two have double halos, and three have an undetermined halo structure. The ratio of observed double to simple halos can be explained by the projection of double halos randomly oriented in three dimensions provided the ratio of component separation to diameter, R, is less than two. Since doubles without a core have R between two and four, the mechanism of radio galaxy formation is likely to produce a core for low values of R. From the present investigation it is impossible to conclude whether there exists a class of core-halo radio galaxies with simple halos (R [...] 1) or whether the observed core-halo objects represent the low-R end of the ensemble of double radio sources
SU‐GG‐J‐35: Application of a Direct Scatter Correction Algorithm to EPID‐Based Megavoltage Cone‐Beam CT
No full text
(No) More Marching Cubes
No full textIsosurfaces, one of the most fundamental volumetric visualization tools, are commonly rendered using the wellknown Marching Cubes cases that approximate contours of trilinearly-interpolated scalar fields. While a complete set of cases has recently been published by Nielson, the formal proof that these cases are the only ones possible and that they are topologically correct is difficult to follow. We present a more straightforward proof of the correctness and completeness of these cases based on a variation of the Dividing Cubes algorithm. Since this proof is based on topological arguments and a divide-and-conquer approach, this also sets the stage for developing tessellation cases for higher-order interpolants and for the quadrilinear interpolant in four dimensions. We also demonstrate that, apart from degenerate cases, Nielson's cases are in fact subsets of two basic configurations of the trilinear interpolant.Eurographics/IEEE VGTC Symposium on Volume Graphic
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