Vertex-transitive triangulations of compact orientable 2-manifolds

AbstractIn this note we construct two infinite families of vertex-transitive triangulations of compact orientable 2-manifolds. Included in these families are two of the best known “classical” examples, viz., the triangulation of the genus 3 surface admitting the group PSL(2, 7) and the triangulation of the genus 7 surface admitting SL(2, 8)

Cohomological Constructions of Regular Cyclic Coverings of the Platonic Maps

AbstractIn we described the regular maps and hypermaps which are cyclic coverings of the Platonic maps, branched over the face centers, vertices or midpoints of edges. Here we determine cochains by which these coverings can be explicitly constructed

Diagnostics and treatment of small intestine tumors in our own experience

Introduction. Small intestine cancers are a difficult oncological problem. Lack of specific symptoms and difficulties with accessing the location even for advanced diagnostic techniques delay the diagnosis and implementation of appropriate treatment. Aim. Analysis of incidence, clinical symptoms, diagnostic methods and results of treatment of small intestine tumors in the material of the Maria Skłodowska-Curie Institute — Oncology Center (MSCI) in Warsaw. Material and method. A retrospective analysis of 54 patients undergoing surgery for small intestine tumor in the years 2006–2015. The evaluated group consisted of 26 (48%) males, 28 (52%) females, median age was 63.5 ± 13.5 years (23–86). Results. In the study group 18 (33%) cases of sarcomas were found, including 16 (30%) cases of GIST. The remaining cases were diagnosed as: adenocarcinoma — 13 patients (24%), neuroendocrine tumor (NET) — 8 (15%), malignant melanoma — 6 (11%), lymphoma — 3 (6%) and benign tumors — 6 (11%). Symptoms included gastrointestinal bleeding (55.5%), abdominal pain (48%), weight loss (31.5%), nausea (30%), vomiting (24%), flatulence (24%), inte­stinal passage disturbances (15%). In 70% of patients anemia was diagnosed, which in 33% required an average of 4.5 packed red blood cells (PRBC) units (range 1–100) to be transfused before treatment. The test that led to diagnosis was in 26 (48%) cases computed tomography, in 8 (15%) cases capsule endoscopy and in 5 (9%) cases double-balloon enteroscopy. Partial resection of the small intestine with regional lymph nodes was performed in 38 patients (70%), local excision in 5 (9%) patients and anastomosis gastric pass in 4 (7%) patients. So far, 17 (31%) deaths have been reported in this group of patients. 5-year survival was 93.8% for sarcomas, 53.9% for SIC, 66.7% for GEP-NET. Conclusions. Partial resection of the small intestine remains the basic method of radical surgical treatment. Both diagnostics and treatment should be carried out in reference centers

Prospective monitoring of the early treatment results of the GI tract tumours at the Oncology Centre in Warsaw

The current treatment of GI tract tumours is based to a large degree on the combined use of varied types of therapy: surgery, chemotherapy, irradiation. Severe post-operative complications may significantly affect the possibilities of application of non-surgical methods of treatment. Therefore, monitoring the early results of surgical treatment is extremely crucial to ensuring the appropriate necessary follow up and keep the risk of post-operative complications to a minimum. This paper describes the methodology of prospective collection of clinical data, which allows monitoring the quality of the surgical treatment of GI tumours on a current basis. On the basis of the data collected in the period from 2010 to 2015, the results of the analysis of three types of surgeries were presented (anterior resection of the anus, right hemicolectomy and a total gastric resection) and the actions taken on the basis of the annual report concerning the post-operative complication risks were described. Moreover, the examples of the application of prospectively collected clinical information for academic purposes were presented

Ocena efektywności kompresji mammogramów

Background: Lossy image coding significantly improves performance over lossless methods, but a reliable control of diagnostic accuracy regarding compressed images is necessary. The acceptable range of compression ratios must be safe with respect to as many objective criteria as possible. This study evaluates the compression efficiency of digital mammograms in both numerically lossless (reversible) and lossy (irreversible) manner. Effective compression methods and concepts were examined to increase archiving and telediagnosis performance. Materials/Methods Lossless compression as a primary applicable tool for medical applications was verified on a set 131 mammograms. Moreover, nine radiologists participated in the evaluation of lossy compression of mammograms. Subjective rating of diagnostically important features brought a set of mean rates given for each test image. The lesion detection test resulted in binary decision data analyzed statistically. The radiologists rated and interpreted malignant and benign lesions, representative pathology symptoms, and other structures susceptible to compression distortions contained in 22 original and 62 reconstructed mammograms. Test mammograms were collected in two radiology centers for three years and then selected according to diagnostic content suitable for an evaluation of compression effects. Results: Lossless compression efficiency of the tested coders varied, but CALIC, JPEG-LS, and SPIHT performed the best. The evaluation of lossy compression effects affecting detection ability was based on ROC-like analysis. Assuming a two-sided significance level of p=0.05, the null hypothesis that lower bit rate reconstructions are as useful for diagnosis as the originals was false in sensitivity tests with 0.04 bpp mammograms. However, verification of the same hypothesis with 0.1 bpp reconstructions suggested their acceptance. Moreover, the 1 bpp reconstructions were rated very similarly to the original mammograms in the diagnostic quality evaluation test, but the quality of 0.6 bpp and 0.1 bpp reconstructions was decreased. Conclusions: The compression performance of the most effective reversible coders is rather unsatisfactory. The subjective rating with the diagnostic criteria of image quality was more sensitive to distortions caused by lossy compression compared with the pathology detection test. The observers constituted 14:1 as the accepted ratio of lossy wavelet compression for test mammograms. This is significantly higher than the mean ratio of 2:1 achieved with lossless methods

Prospektywne monitorowanie wczesnych wyników leczenia chirurgicznego nowotworów układu pokarmowego w Centrum Onkologii w Warszawie

Współczesne leczenie nowotworów układu pokarmowego opiera się w dużej mierze na skojarzonym wykorzystaniu różnych sposobów terapii: chirurgii, chemioterapii, radioterapii. Ciężkie powikłania pooperacyjne mogą w znaczący sposób wpływać na możliwości zastosowania pozachirurgicznych metod leczenia. Tym bardziej istotne jest monitorowanie wczesnych wyników leczenia chirurgicznego, aby w razie konieczności odpowiednio reagować i zmniejszać do minimum ryzyko powikłań pooperacyjnych. W prezentowanej pracy opisano metodologię prospektywnego gromadzenia danych klinicznych, pozwalającą na bieżące monitorowanie jakości leczenia chirurgicznego nowotworów układu pokarmowego. Na podstawie danych zgromadzonych w okresie od 2010 do 2015 roku przedstawiono wyniki analizy dla wybranych trzech typów operacji (przednia resekcja odbytnicy, hemikolektomia prawostronna oraz całkowita resekcja żołądka) i opisano działania, jakie podejmowano na podstawie corocznych raportów dotyczących ryzyka powikłań pooperacyjnych. Ponadto przedstawiono przykłady zastosowania dla celów naukowych, prospektywnie zgromadzonych informacji klinicznych

Maximal integral point sets in affine planes over finite fields

Motivated by integral point sets in the Euclidean plane, we consider integral point sets in affine planes over finite fields. An integral point set is a set of points in the affine plane $\mathbb{F}_q^2$ over a finite field $\mathbb{F}_q$, where the formally defined squared Euclidean distance of every pair of points is a square in $\mathbb{F}_q$. It turns out that integral point sets over $\mathbb{F}_q$ can also be characterized as affine point sets determining certain prescribed directions, which gives a relation to the work of Blokhuis. Furthermore, in one important sub-case integral point sets can be restated as cliques in Paley graphs of square order. In this article we give new results on the automorphisms of integral point sets and classify maximal integral point sets over $\mathbb{F}_q$ for $q\le 47$. Furthermore, we give two series of maximal integral point sets and prove their maximality.Comment: 18 pages, 3 figures, 2 table

Metastatic tumors of pancreas — whether and when surgical intervention is gainful for diseased people. Retrospective analysis of data from three surgery centers

Introduction. Metastatic tumors in the pancreas constitute a small (2–5%), but steadily growing percentage of all neoplasms of this organ. The aim of the study was to analyze the surgical treatment of metastases in the pancreas, in particular its effectiveness and the risk of surgical complications. Material and methods. The retrospective analysis was performed on 21 patients treated surgically in three surgical centers. This group included 16 women (76%) and 5 men (24%). The median age at the time of diagnosis of the underlying disease was 55.5 years (41–71). We analyzed the location of secondary lesions, their size, number, type and radicality of surgical intervention, histopathological diagnosis of the disease, as well as the occurrence of postoperative complications. Results. The starting point for metastatic lesions in 16 patients (76%) was renal cell carcinoma (RCC), in other cases — skin melanoma, eyeball melanoma, adenocarcinoma of the rectum, non-small-cell bronchi carcinoma. R0 radical surgery was performed in 15 patients (74%) and perioperative mortality was 5% (1 patient died). The median total survival time was 151 months (10–342), with 168 months for RCC (25–344) and 62 months for the remaining cancers (10–241). Conclusions. The main factor that determines the patient’s future fate is the type of primary neoplasm and surgical treatment of metastatic tumors in the pancreas is the best solution for selected RCC cases