1,649 research outputs found

    Projective Bundle Adjustment from Arbitrary Initialization Using the Variable Projection Method

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    Bundle adjustment is used in structure-from-motion pipelines as final refinement stage requiring a sufficiently good initialization to reach a useful local mininum. Starting from an arbitrary initialization almost always gets trapped in a poor minimum. In this work we aim to obtain an initialization-free approach which returns global minima from a large proportion of purely random starting points. Our key inspiration lies in the success of the Variable Projection (VarPro) method for affine factorization problems, which have close to 100% chance of reaching a global minimum from random initialization. We find empirically that this desirable behaviour does not directly carry over to the projective case, and we consequently design and evaluate strategies to overcome this limitation. Also, by unifying the affine and the projective camera settings, we obtain numerically better conditioned reformulations of original bundle adjustment algorithms

    Metastatic seeding of colon adenocarcinoma manifesting as synchronous breast and chest wall localization: report of a case.

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    Colon carcinoma rarely metastasizes to the breast and it is usually associated with a poor prognosis. Even rarer is metastatic seeding of colon cancer cells in an intramammary location after surgery. Including a primary breast malignancy in the differential diagnosis of such cases is mandatory. We report a rare case of double seeding implantation of colon adenocarcinoma inside the breast parenchyma and intercostal muscles 6 years after resection of a pulmonary metastasis from colon adenocarcinoma. The metastasis was revealed by the presence of bone metaplasia in the intercostal muscles. We discuss how negative immunostaining for estrogen receptors, progesterone receptors, and HER-2, along with the immunohistochemical pattern of cytokeratin (CK) 20+/7-/5- and CDX2-positive immunostaining, excludes a primary breast malignancy, namely, a "matrix-producing" carcinoma, from the differential diagnosis. We also present the hypothesis of a paracrine pathogenetic mechanism to explain the bone metaplasia

    Hashimoto ThYroiditis Coexistent with Papillary Thyroid Carcinoma

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    Several studies report a higher rate of papillary thyroid carcinomas (PTC) in patients with Hashimoto thyroiditis (HT), indicating a possible correlation between the two diseases. We studied a group of 89 subjects undergoing surgery for thyroid carcinomas compared with a control group of 89 subjects operated on for normofunctioning goiter, and a second group of 47 patients undergoing total thyroidectomy for HT. Association with HT was found in 19 of the 71 PTC subjects (26.7%) and in 8 goiter patients (8.9%), which was a significant difference (P < 0.02). Thirteen of the HT patients, mostly with the nodular form, showed coexistent PTC (27.6%). HT and PTC coexisted in several morphological, immunohistochemical, and biomolecular aspects; increased incidence of PTC in HT patients might therefore indicate that HT is a precursor of thyroid cancer. Further studies are required, however, in order to confirm this hypothesis; until then, HT patients should undergo careful clinical and technical follow-up

    Adaptive matrix algebras in unconstrained minimization

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    In this paper we study adaptive L(k)QNmethods, involving special matrix algebras of low complexity, to solve general (non-structured) unconstrained minimization problems. These methods, which generalize the classical BFGS method, are based on an iterative formula which exploits, at each step, an ad hocchosen matrix algebra L(k). A global convergence result is obtained under suitable assumptions on f

    TTF-1/p63-positive poorly differentiated NSCLC: A histogenetic hypothesis from the basal reserve cell of the terminal respiratory unit

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    TTF-1 is expressed in the alveolar epithelium and in the basal cells of distal terminal bronchioles. It is considered the most sensitive and specific marker to define the adenocarcinoma arising from the terminal respiratory unit (TRU). TTF-1, CK7, CK5/6, p63 and p40 are useful for typifying the majority of non-small-cell lung cancers, with TTF and CK7 being typically expressed in adenocarcinomas and the latter three being expressed in squamous cell carcinoma. As tumors with coexpression of both TTF-1 and p63 in the same cells are rare, we describe different cases that coexpress them, suggesting a histogenetic hypothesis of their origin. We report 10 cases of poorly differentiated non-small-cell lung carcinoma (PD-NSCLC). Immunohistochemistry was performed by using TTF-1, p63, p40 (∆Np63), CK5/6 and CK7. EGFR and BRAF gene mutational analysis was performed by using real-time PCR. All the cases showed coexpression of p63 and TTF-1. Six of them showing CK7+ and CK5/6− immunostaining were diagnosed as “TTF-1+ p63+ adenocarcinoma”. The other cases of PD-NSCLC, despite the positivity for CK5/6, were diagnosed as “adenocarcinoma, solid variant”, in keeping with the presence of TTF-1 expression and p40 negativity. A “wild type” genotype of EGFR was evidenced in all cases. TTF1 stained positively the alveolar epithelium and the basal reserve cells of TRU, with the latter also being positive for p63. The coexpression of p63 and TTF-1 could suggest the origin from the basal reserve cells of TRU and represent the capability to differentiate towards different histogenetic lines. More aggressive clinical and morphological features could characterize these “basal-type tumors” like those in the better known “basal-like” cancer of the breast

    Validity of needle core biopsy in the histological characterisation of mammary lesions

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    Over the last few years, there has been an enormous increase in the use of needle core biopsy (CB) for the histopathological characterisation of suspect lesions of the breast. The aim of this study was to verify the diagnostic reliability of CB by comparing the histological results obtained with the use of this technique with those obtained from the whole of the surgically resected specimen. We studied 198 out of 426 patients with clinically and/or radiologically suspect breast lesions. We found correspondence between the histological examination of the whole of the excised specimen and that of the CB in 94.9% of the cases of infiltrating carcinoma and in 71.4% of those involving ductal carcinomas in situ. The predictive value of CB was 98.9%, sensitivity was 96.1% and specificity 93.3%. These results confirmed that CB is an extremely reliable diagnostic tool in the definition of breast lesions

    Incarcerated hernia in a trocar site following laparoscopic gastric bypass

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    This paper reports a case of small bowel occlusion due to the herniation of an ileal ansa at the site of the insertion of a 12-mm trocar. A 28-year-old obese female patient underwent laparoscopic surgery for gastric bypass, the skin incisions of the trocar insertion sites were closed with absorbable sutures. Small bowel occlusion occurred on post-operative day 6 and the patient again underwent laparoscopic surgery. Laparoscopic exploration confirmed the suspected presence of the incarcerated hernia of an ileal ansa at the site of the trocar insertion which was freed without any need for bowel resection. The fascial defect was successfully closed under direct vision with the use of a special system of fascial sutures

    Primary extranodal non-Hodgkin lymphomas of the uterus and the breast: report of three cases

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    The authors describe one case of a rare primitive non-Hodgkin lymphoma of the uterus, and two cases of primary non-Hodgkin lymphoma of the breast. Histologically, the uterine lymphoma, although clinically confined to the uterus, was a diffuse large cell lymphoma, group G according to the Working formulation for Clinical Usage. The two cases of breast lymphoma were a centrocytic-centroblastic and a lymphoplasmocytoid non-Hodgkin lymphoma, respectively. All cases were initally treated with radical surgery plus radiotherapy, but the first patient showed an early recurrence at distant sites, which required systemic cytotoxic chemotherapy. The patient with uterine non-Hodgkin lymphoma received a very intense regimen-i.e. the ProMACE-Cytabom-because of the unfavourable histology, while the two patients with primary breast non-Hodgkin lymphoma received less aggressive CHOP and CVP chemotherapy. All patients are still alive and free of disease 3 to 6 years after initial diagnosis. These cases stress the systemic nature of non-Hodgkin lymphomas even if apparently localized to a single extranodal organ. Thus, although a definitive therapeutic strategy cannot be drawn from the rare and occasional reports in the medical literature, primary extranodal lymphomas require integrated multimodality therapy with radiotherapy and/or chemotherapy. © 1995 W.B. Saunders Company Limited
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