As an extension to a recently proposed local linear approximation method we present an algorithm that generates more compact solutions for supervised-learning problems. Given a network of linear ...models each trained to approximate the target function in a local region of the input space, the algorithm reduces the number of the models significantly without diminishing the accuracy of the approximation. It fuses linear models by combining their local regions of validity to more complex, non-symmetrically shaped ones. A neighborhood graph introducing edges in a purely data-driven manner between adjacent linear models is used to determine which models should be fused. The also extended model for a region of validity allows to detect automatically data which is novel to a trained network and should be regarded as an outlier. The effectiveness of the proposed methods is shown with a benchmark test achieving a five times smaller RMSE than the best competitors
The histological detection of a peritumoral lymphocytic infiltration (PLI) and a sharp tumor border in patients with squamous cell carcinoma (SCC) of the larynx, pharynx or oral cavity is inversely ...correlated with the development of cervical lymph node metastases and is therefore a favorable prognostic factor. However, preoperative biopsies are often too small for an evaluation of these tumor features. Here, we examined retrospectively whether elevation of peritumoral density values as determined by contrast-enhanced computed tomography (CT) correlates with PLI and the presence of cervical lymph node metastases. A total of 40 patients with primarily resected SCC were studied (pT1=8, pT2=13, pT3=9, pT4=10); 25 patients were pN-positive. All tumors were histologically analyzed regarding PLI (present or not) and the tumor border (sharp or infiltrating). Based on standardized CT examinations (90 ml contrast agent at 1.5 ml/s), repeated region-of-interest (ROI)-based peritumoral density measurements were obtained. Correlations between CT density, PLI, tumor border and metastatic involvement of regional lymph nodes were statistically evaluated. CT densities were significantly higher (P<0.001) in patients with PLI and sharp tumor borders than in patients without PLI and patients with infiltrating tumor borders. Moreover, the presence of PLI, sharp tumor borders and elevated peritumoral CT densities were each correlated with the absence of lymph node metastases (P<0.001). An elevation of peritumoral CT densities is linked to PLI and sharp tumor borders on histology and a lower risk to develop lymph node metastases. For a patient-adapted therapy, these relations have to be prospectively evaluated regarding their prognostic relevance.
Although it is generally accepted that destruction and remodeling of temporal bone associated with middle ear cholesteatoma is mainly caused by the action of osteoclasts, it has been shown that ...neutral collagenases also play a role in predigesting the osteoid layer and exposing the mineralized bone to osteoclastic activity. Here we show that gelatinase B (matrix metalloproteinase-9) is over-expressed in cholesteatoma compared to external ear canal skin (EACS). Expression of MMP-9 in cholesteatoma mainly occurs in suprabasal layers, and more rarely in basal layers of cholesteatoma epithelium, as well as in inflammatory cells of the perimatrix. We further analyzed the influence of cholesteatoma debris, cholesteatoma granulation tissue, and cholesteatoma components such as keratin, cholesterol and bacterial endotoxin on the expression of MMPs in EACS keratinocytes. We show that cholesteatoma debris and granulation tissue extract both induced the secretion of MMP-9 by EACS keratinocytes, while keratin. bacterial lipopolysaccharide (LPS) or cholesterol did not show any effect. We further performed co-incubation and immunoprecipitation experiments using neutralizing interleukin-1alpha, EGF, TGF-beta, TGF-alpha, interleukin-6 and TNF-alpha antibodies. Inhibition of MMP-9 up-regulation by debris or granulation tissue extract could be revealed with diverse cytokine antibodies. The results are discussed with regard to previously published studies.
We sought to assess the value of aqueous and barium-containing contrast agents in the detection of pharyngeal perforation.
Visual and objective in vitro comparisons of an iodinated aqueous contrast ...agent, a 50% weight/volume barium suspension, and a 100% weight/volume barium suspension were performed. Moreover, to exclude pharyngeal perforation after surgery, we prospectively examined 109 patients by pharyngography, using the aqueous contrast agent and the 100% weight/volume barium suspension. All patients with a pharyngeal perforation were followed up clinically to exclude complications due to barium application.
As opposed to the 100% weight/volume barium suspension, in vitro comparison between the aqueous contrast agent and the 50% weight/volume barium suspension yielded no substantial differences. Seventeen perforations could be detected with the aqueous contrast agent. Although 10 of 17 perforations could be slightly better visualized with the 100% weight/volume barium suspension, two perforations were missed with this agent. Five perforations were equally well detected with both.
Because of a higher radiopacity, 100% weight/volume barium suspensions may more sharply delineate perforations. However, in contrast to aqueous contrast media, narrow pharyngeal perforations can be missed. Thus, the use of a 100% weight/volume barium suspension does not improve the detection of pharyngeal perforation.
Aflatoxin B1 is a human hepatocarcinogen. It is also a known point mutagen in bacteria and mammalian cells. This mutagenic activity may be at least partly responsible for its carcinogenic activity. ...However, recent studies show that aflatoxin B1 induces mitotic recombination in the yeast Saccharomyces cerevisiae. Because numerous reports have implicated mitotic recombination in mechanisms leading to carcinogenesis and because no one has shown that aflatoxin B1 induces recombination in mammalian cells, we decided to examine the ability of aflatoxin B1 to induce recombination in a mammalian cell line. We used a combination of methods, analysis for loss of heterozygosity and whole chromosome in situ hybridization, to identify mechanisms of chromosome mutation, including mitotic recombination in the mammalian L5178Y mouse lymphoma cell system. Our experiments revealed that mitotic recombination caused ~60% or more of the aflatoxin B1-induced mutagenic lesions in this cell system. Thus, mitotic recombination plays an important role in aflatoxin B1-induced mutagenesis in mammalian cells and possibly in chemically induced mutagenesis and carcinogenesis. This work suggests that multiple genetic lesions may be involved in aflatoxin B1-induced pathology.
Neural networks trained on datasets such as ImageNet have led to major advances in visual object classification. One obstacle that prevents networks from reasoning more deeply about complex scenes ...and situations, and from integrating visual knowledge with natural language, like humans do, is their lack of common sense knowledge about the physical world. Videos, unlike still images, contain a wealth of detailed information about the physical world. However, most labelled video datasets represent high-level concepts rather than detailed physical aspects about actions and scenes. In this work, we describe our ongoing collection of the "something-something" database of video prediction tasks whose solutions require a common sense understanding of the depicted situation. The database currently contains more than 100,000 videos across 174 classes, which are defined as caption-templates. We also describe the challenges in crowd-sourcing this data at scale.
PDF