674 research outputs found
Quantitative Studies of the Lung of the Domestic Fowl (Gallus gallus var. domesticus)
Comprehensive quantitiative studies on the lung of the domestic fow, (Gallus galluf var. domesticus).
have been made. The data obtained were VL/W 14.65 ± 3.17 cm3/kg; Sa/W 18.08 ±2.51 cm2 /g; rht
0.322 ± 0.01 um; Dto/W 12. 79 ± 2.20 mlo/minlmmHglkg; dan DLo/W 1.39 ± 0.36 mlo/minlmmHglkg.
These values are compared with those reported by other authors, and possible reasons for the differences
are discussed. The mean values for many of the parameters have been calculated so that the values so
obtained may form a basis for further investigations
The Oxidation State of Iron in Silicate Minerals from the Matrices of CO Carbonaceous Chondrites
No abstract available
Reconstruction of the trachea with a tubed radial forearm free flap
AbstractBackgroundWe present the case of a patient with adenoid cystic carcinoma of the trachea who had 60 mm of the trachea excised and reconstructed with a stented radial forearm free flap. The patient was well in the immediate postoperative period with good function of the neotrachea. Problems developing after the reconstruction included proximal stricture, sputum retention, and recurrent pneumonia.ResultThe patient died of malignant hypercalcemia 16 months after the reconstruction. To our knowledge this is the first reported case of a total tracheal resection and reconstruction with a combination of free tissue transfer and internal stenting.ConclusionWe conclude that tracheal reconstruction has the potential to provide a reliable airway in patients not able to be reconstructed with a primary anastomosis
Some recent developments in quantization of fractal measures
We give an overview on the quantization problem for fractal measures,
including some related results and methods which have been developed in the
last decades. Based on the work of Graf and Luschgy, we propose a three-step
procedure to estimate the quantization errors. We survey some recent progress,
which makes use of this procedure, including the quantization for self-affine
measures, Markov-type measures on graph-directed fractals, and product measures
on multiscale Moran sets. Several open problems are mentioned.Comment: 13 page
The Oxidation State of Iron in Silicate Minerals from the Matrices of CO Carbonaceous Chondrites
No abstract available
The Elamite Cylinder Seal Corpus, c.3500 - 1000 BC
The ancient region of Elam (southwestern Iran) has produced a significant assemblage of cylinder seals across a considerable chronological span. Unlike the glyptic material from the related and neighbouring region Mesopotamia, the Elamite cylinder seals have not previously been studied in detailed reference to one another, nor has there been an established paradigm of stylistic development articulated. This study addresses this lacuna by compiling all the published cylinder seals from Elam (as defined here, thus incorporating the historical provinces of Khuzistan, Luristan and Fars), from their earliest appearance (c.3500 BC), throughout the era of their typological dominance (over stamp seals, thus this study departs c.1000 BC). This compilation is presented in the Elamite Cylinder Seal Catalogue (Volume II), and is annotated and described through the annunciation of eighteen chronologically defined developmental styles (with another two non-chronological type classifications and four miscellaneous groups). Through the further analysis of this data, including the newly formulated and articulated styles, several facets and problems of Elamite glyptic material have been addressed (and thus the reliance upon assumed similarity in type and function with the Mesopotamian glyptic material is abandoned). These problems particularly pertain to the function of cylinder seals in Elam and the type and form of the Elamite-Mesopotamian glyptic interaction. In regards to function, a standard administrative function can be discerned, though of varying types and forms across the region and the period of study. Other, non-standard, symbolic glyptic functions can also be demonstrated in the Corpus, including the apparent proliferation of a form known as the ‘votive’ seal, perhaps a specifically Elamite form. The analysis of the style type (whether ‘Elamite’, ‘Mesopotamian Related’ or ‘Shared Elamite-Mesopotamian’), in association with their relative geographical and chronological distribution, has also enabled the discussion of the nature of Elamite-Mesopotamian glyptic interaction, and thereby the constitution of Elamite civilisation (especially in regards to Mesopotamian cultural impact and influence, and thus the testing of several previously presented paradigms [Amiet 1979a; 1979b; Miroschedji 2003])
Optimal topological simplification of discrete functions on surfaces
We solve the problem of minimizing the number of critical points among all
functions on a surface within a prescribed distance {\delta} from a given input
function. The result is achieved by establishing a connection between discrete
Morse theory and persistent homology. Our method completely removes homological
noise with persistence less than 2{\delta}, constructively proving the
tightness of a lower bound on the number of critical points given by the
stability theorem of persistent homology in dimension two for any input
function. We also show that an optimal solution can be computed in linear time
after persistence pairs have been computed.Comment: 27 pages, 8 figure
Non-linear regression models for Approximate Bayesian Computation
Approximate Bayesian inference on the basis of summary statistics is
well-suited to complex problems for which the likelihood is either
mathematically or computationally intractable. However the methods that use
rejection suffer from the curse of dimensionality when the number of summary
statistics is increased. Here we propose a machine-learning approach to the
estimation of the posterior density by introducing two innovations. The new
method fits a nonlinear conditional heteroscedastic regression of the parameter
on the summary statistics, and then adaptively improves estimation using
importance sampling. The new algorithm is compared to the state-of-the-art
approximate Bayesian methods, and achieves considerable reduction of the
computational burden in two examples of inference in statistical genetics and
in a queueing model.Comment: 4 figures; version 3 minor changes; to appear in Statistics and
Computin
Paraneoplastic thrombocytosis in ovarian cancer
<p>Background: The mechanisms of paraneoplastic thrombocytosis in ovarian cancer and the role that
platelets play in abetting cancer growth are unclear.</p>
<p>Methods: We analyzed clinical data on 619 patients with epithelial ovarian cancer to test associations between platelet counts and disease outcome. Human samples and mouse
models of epithelial ovarian cancer were used to explore the underlying mechanisms
of paraneoplastic thrombocytosis. The effects of platelets on tumor growth and angiogenesis were ascertained.</p>
<p>Results: Thrombocytosis was significantly associated with advanced disease and shortened
survival. Plasma levels of thrombopoietin and interleukin-6 were significantly elevated
in patients who had thrombocytosis as compared with those who did not. In mouse
models, increased hepatic thrombopoietin synthesis in response to tumor-derived
interleukin-6 was an underlying mechanism of paraneoplastic thrombocytosis. Tumorderived interleukin-6 and hepatic thrombopoietin were also linked to thrombocytosis
in patients. Silencing thrombopoietin and interleukin-6 abrogated thrombocytosis in
tumor-bearing mice. Anti–interleukin-6 antibody treatment significantly reduced platelet counts in tumor-bearing mice and in patients with epithelial ovarian cancer. In
addition, neutralizing interleukin-6 significantly enhanced the therapeutic efficacy of
paclitaxel in mouse models of epithelial ovarian cancer. The use of an antiplatelet
antibody to halve platelet counts in tumor-bearing mice significantly reduced tumor
growth and angiogenesis.</p>
<p>Conclusions: These findings support the existence of a paracrine circuit wherein increased production of thrombopoietic cytokines in tumor and host tissue leads to paraneoplastic
thrombocytosis, which fuels tumor growth. We speculate that countering paraneoplastic thrombocytosis either directly or indirectly by targeting these cytokines may have
therapeutic potential. </p>
Inherited predisposition to breast cancer in the Carolina Breast Cancer Study
The Carolina Breast Cancer Study (CBCS) phases I–II was a case-control study of biological and social risk factors for invasive breast cancer that enrolled cases and controls between 1993 and 1999. Case selection was population-based and stratified by ancestry and age at diagnosis. Controls were matched to cases by age, self-identified race, and neighborhood of residence. Sequencing genomic DNA from 1370 cases and 1635 controls yielded odds ratios (with 95% confidence limits) for breast cancer of all subtypes of 26.7 (3.59, 189.1) for BRCA1, 8.8 (3.44, 22.48) for BRCA2, and 9.0 (2.06, 39.60) for PALB2; and for triple-negative breast cancer (TNBC) of 55.0 (7.01, 431.4) for BRCA1, 12.1 (4.18, 35.12) for BRCA2, and 10.8 (1.97, 59.11) for PALB2. Overall, 5.6% of patients carried a pathogenic variant in BRCA1, BRCA2, PALB2, or TP53, the four most highly penetrant breast cancer genes. Analysis of cases by tumor subtype revealed the expected association of TNBC versus other tumor subtypes with BRCA1, and suggested a significant association between TNBC versus other tumor subtypes with BRCA2 or PALB2 among African-American (AA) patients [2.95 (1.18, 7.37)], but not among European-American (EA) patients [0.62 (0.18, 2.09)]. AA patients with pathogenic variants in BRCA2 or PALB2 were 11 times more likely to be diagnosed with TNBC versus another tumor subtype than were EA patients with pathogenic variants in either of these genes (P = 0.001). If this pattern is confirmed in other comparisons of similarly ascertained AA and EA breast cancer patients, it could in part explain the higher prevalence of TNBC among AA breast cancer patients
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