Variations on the arbelos

We recall the ancient notion of arbelos and introduce a number of concepts generalizing it. We follow the ideas presented by J. Sondow in his article on parbelos, the parabolic analogue of the classic arbelos. Our concepts concern the curves constructed of arcs which resemble each other and surfaces obtained in a similar way. We pay special attention to ellarbelos, the curves built of semi-ellipses, because of their possible application in engineering, e.g. in determining the static moments of arc rod constructions or in problems of structural stability and durability of constructions

On some methods of calculating the integrals of trigonometric rational functions

The paper presents original methods of calculating integrals of selected trigonometric rational functions

Diagnostic accuracy of liquid biopsy in endometrial cancer

Background: Liquid biopsy is a minimally invasive collection of a patient body fluid sample. In oncology, they offer several advantages compared to traditional tissue biopsies. However, the potential of this method in endometrial cancer (EC) remains poorly explored. We studied the utility of tumor educated platelets (TEPs) and circulating tumor DNA (ctDNA) for preoperative EC diagnosis, including histology determination. Methods: TEPs from 295 subjects (53 EC patients, 38 patients with benign gynecologic conditions, and 204 healthy women) were RNA-sequenced. DNA sequencing data were obtained for 519 primary tumor tissues and 16 plasma samples. Artificial intelligence was applied to sample classification. Results: Platelet-dedicated classifier yielded AUC of 97.5% in the test set when discriminating between healthy subjects and cancer patients. However, the discrimination between endometrial cancer and benign gynecologic conditions was more challenging, with AUC of 84.1%. ctDNA-dedicated classifier discriminated primary tumor tissue samples with AUC of 96% and ctDNA blood samples with AUC of 69.8%. Conclusions: Liquid biopsies show potential in EC diagnosis. Both TEPs and ctDNA profiles coupled with artificial intelligence constitute a source of useful information. Further work involving more cases is warranted.publishedVersio

Heart failure in Poland: Left ventricular assist device destination therapy and other challenges of interventional cardiology and cardiac surgery

Patients with severe heart failure (HF), who are not eligible for cardiac transplantation and receive optimal medical management, based mainly on the use of pharmacological treatment and devices such as resynchronization therapy (implantable cardioverter-defibrillator), achieve poor clinical outcomes and constitute a group with extremely poor prognosis. Currently, the technology used in the latest generation left ventricular assist devices (LVADs), such as the HeartMate 3, makes it possible to achieve patient survival at the level obtained by patients after heart transplantation, and they can be used not only in patients eligible for heart transplantation as a bridge to transplant, but also in those with significantly worse prognosis, who are ineligible for heart transplantation as destination therapy. The objective of this publication is to present recommendations from experts in cardiology and cardiac surgery, supported by clinical trial results, on the use of LVADs as a destination therapy in HF patients who are not eligible for cardiac transplantation. The paper also presents the issue of cardiac transplantation and extracorporeal membrane oxygenation therapy in Poland, as well as current challenges faced by interventional cardiology and cardiac surgery in Poland

Mechanical thrombectomy in acute stroke – Five years of experience in Poland

Objectives Mechanical thrombectomy (MT) is not reimbursed by the Polish public health system. We present a description of 5 years of experience with MT in acute stroke in Comprehensive Stroke Centers (CSCs) in Poland. Methods and results We retrospectively analyzed the results of a structured questionnaire from 23 out of 25 identified CSCs and 22 data sets that include 61 clinical, radiological and outcome measures. Results Most of the CSCs (74%) were founded at University Hospitals and most (65.2%) work round the clock. In 78.3% of them, the working teams are composed of neurologists and neuro-radiologists. All CSCs perform CT and angio-CT before MT. In total 586 patients were subjected to MT and data from 531 of them were analyzed. Mean time laps from stroke onset to groin puncture was 250±99min. 90.3% of the studied patients had MT within 6h from stroke onset; 59.3% of them were treated with IV rt-PA prior to MT; 15.1% had IA rt-PA during MT and 4.7% – emergent stenting of a large vessel. M1 of MCA was occluded in 47.8% of cases. The Solitaire device was used in 53% of cases. Successful recanalization (TICI2b–TICI3) was achieved in 64.6% of cases and 53.4% of patients did not experience hemorrhagic transformation. Clinical improvement on discharge was noticed in 53.7% of cases, futile recanalization – in 30.7%, mRS of 0–2 – in 31.4% and mRS of 6 in 22% of cases. Conclusion Our results can help harmonize standards for MT in Poland according to international guidelines

Freedom to provide VoIP services based on domestic and UE legal regulations

The subject of this master thesis is the freedom to provide services in the context of Internet telephony (VoIP). Covers both the EU regulations as well as the domestic law, Moreover covers comparative approach of both these legal systems. In addition, describes the types of services, the division and characteristics, including technical terms. The subjected master thesis also pointed out some of the loopholes that still exist in the current regulations from the end users and the VoIP service providers perspective.Przedmiotem niniejszej pracy jest swoboda świadczenia usług w kontekście telefonii internetowej (VoIP). Obejmuje swoim zakresem zarówno regulacje prawne Unii Europejskiej jak również polskie orzecznictwo, a także komparatystyczne ujęcie obu systemów. Ponadto opisano rodzaje usług, ich podział oraz charakterystykę, również w technicznym ujęciu tegoż zagadnienia. Dodatkowo wskazano na niektóre luki prawne jakie nadal występują w obecnie obowiązujących regulacjach z perspektywy zarówno użytkownika usług VoIP jak i dostawcy tychże usług

Wpływ kierunku ułożenia ściegów na odporność na zużywanie ścierne szlifowanych płyt trudnościeralnych

The article presents the results of the study of the significance of influence of positioning deposited beads towards direction of abrasive movement, to resistance on grind wear plates HARDPLATE 100S’ abrasive wear. The study on relevance of influence was conducted by using completely randomized design. The range of study has covered testing the metal-material abrasive wear resistance, macroscopic and microscopic metallographic examination and hardness tests.W artykule przedstawiono wyniki badania istotności wpływu kierunku ułożenia ściegów względem kierunku ruchu ścierniwa na odporność na zużywanie ścierne szlifowanych płyt trudnościeralnych HARDPLATE 100S. Badanie istotności wpływu prowadzono stosując program statyczny randomizowany kompletny. Zakres badań obejmował badanie odporności na zużywanie ścierne typu metal-minerał, badania metalograficzne makro- i mikroskopowe oraz pomiar twardości warstwy napawanej

Multi-Scale Structural Assessment of Cellulose Fibres Cement Boards Subjected to High Temperature Treatment

The methodology of multi-scale structural assessment of the different cellulose fibre cement boards subjected to high temperature treatment was proposed. Two specimens were investigated: Board A (air-dry reference specimen) and Board B (exposed to a temperature of 230 °C for 3 h). At macroscale all considered samples were subjected to the three-point bending test. Next, two methodologically different microscopic techniques were used to identify evolution (caused by temperature treatment) of geometrical and mechanical morphology of boards. For that purpose, SEM imaging with EDS analysis and nanoindentation tests were utilized. High temperature was found to have a degrading effect on the fibres contained in the boards. Most of the fibres in the board were burnt-out, or melted into the matrix, leaving cavities and grooves which were visible in all of the tested boards. Nanoindentation tests revealed significant changes of mechanical properties caused by high temperature treatment: “global” decrease of the stiffness (characterized by nanoindentation modulus) and “local” decrease of hardness. The results observed at microscale are in a very good agreement with macroscale behaviour of considered composite. It was shown that it is not sufficient to determine the degree of degradation of fibre-cement boards solely on the basis of bending strength; advanced, microscale laboratory techniques can reveal intrinsic structural changes