567 research outputs found

    Multifractal characteristics of external anal sphincter based on sEMG signals

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    This work presents the application of Multifractal Detrended Fluctuation Analysis for the surface electromyography signals obtained from the patients suffering from rectal cancer. The electrical activity of an external anal sphincter at different levels of medical treatment is considered. The results from standard MFDFA and the EMD--based MFDFA method are compared. Two distinct scaling regions were identified. Within the region of short time scales the calculated spectra exhibit the shift towards higher values of the singularity exponent for both methods. In addition obtained spectra are shifted towards the lower values of singularity exponent for the EMD--based MFDFA.Comment: 10 pages, 6 figures, 2 table

    The distribution of information for sEMG signals in the rectal cancer treatment process

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    The electrical activity of external anal sphincter can be registered with surface electromyography. This signals are known to be highly complex and nonlinear. This work aims in characterisation of the information carried in the signals by harvesting the concept of information entropy. We will focus of two classical measures of the complexity. Firstly the Shannon entropy is addressed. It is related to the probability spectrum of the possible states. Secondly the Spectral entropy is described, as a simple frequency-domain analog of the time-domain Shannon characteristics. We discuss the power spectra for separate time scales and present the characteristics which can represent the dynamics of electrical activity of this specific muscle group. We find that the rest and maximum contraction states represent rather different spectral characteristic of entropy, with close-to-normal contraction and negatively skewed rest state.Comment: 6 pages, 5 figures, 1 tabl

    The impact of splenectomy and diaphragmatic surgeryon perioperative morbidity and overall survival of ovarian cancer patients

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    Objectives: The prognosis of ovarian cancer (OC), among other factors, depends on residual disease after primary debulking surgery (PDS) and initial disease advancement. The main aim of our study was to evaluate the survival benefits of splenectomy and diaphragmatic surgery in OC patients, when the procedures result in resection to no macroscopic residual disease or minimal residual disease [tumor nodules below 2.5 mm according to Sugarbaker’s completeness of cytoreduction score (CC) = 1]. Material and methods: The study included 25 OC patients after splenectomy procedures, 28 patients after diaphragmatic surgery and 17 patients who had undergone both splenectomy and diaphragmatic surgery. Patients’ overall survival (OS) was compared with residual disease-matched controls (47 patients) who had upper abdomen involvement but no requirement for splenectomy and/or diaphragmatic surgery. Results: Overall survival of patients after splenectomy was not significantly different from OS of patients who did not required splenectomy (36.1 vs 31.6 months; p = 0.85). No differences in OS were observed between patients who did and did not require diaphragmatic surgery (31.3 vs 41.8; p = 0.33). Similarly, we found no differences in OS between patients who underwent both splenectomy and diaphragmatic surgery and those patients who did not require either procedure (20.1 vs 31.6 months; p = 0.45). Splenectomies and diaphragmatic surgeries were associated with prolonged hospitalization and length of surgery, however, no specific morbidity related to the procedures was observed. Conclusions: In the cases of advanced OC, diaphragm and spleen involvement do not hamper patient prognosis when adequately resected

    Model tests of wind turbine with a vertical axis of rotation type Lenz 2

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    A building design of vertical axis wind turbines (VAWT) was presented in the article. The construction and operating principle of a wind turbine were described therein. Two VAWT turbine models were compared, i.a. Darrieus and Lenz2, taking their strengths and weaknesses into consideration. 3D solid models of turbine components were presented with the use of SolidWorks software. Using CFD methods, the air flow on two aerodynamic fins, symmetrical and asymmetrical, at different angles of attack were tested. On the basis of flow simulation conducted in FlowSimulation, an asymmetrical fin was chosen as the one showing greater load bearing capacities. Due to the uncertainty of trouble-free operation of Darrieus turbine on construction elements creating the basis thereof, a 3D model of Lenz2 turbine was constructed, which is more reliable and makes turbine self-start possible. On the basis of the research, components were designed and technical docu mentation was compiled

    Astrocytic β-catenin signaling via TCF7L2 regulates synapse development and social behavior

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    The Wnt/β-catenin pathway contains multiple high-confidence risk genes that are linked to neurodevelopmental disorders, including autism spectrum disorder. However, its ubiquitous roles across brain cell types and developmental stages have made it challenging to define its impact on neural circuit development and behavior. Here, we show that TCF7L2, which is a key transcriptional effector of the Wnt/β-catenin pathway, plays a cell-autonomous role in postnatal astrocyte maturation and impacts adult social behavior. TCF7L2 was the dominant Wnt effector that was expressed in both mouse and human astrocytes, with a peak during astrocyte maturation. The conditional knockout of Tcf7l2 in postnatal astrocytes led to an enlargement of astrocytes with defective tiling and gap junction coupling. These mice also exhibited an increase in the number of cortical excitatory and inhibitory synapses and a marked increase in social interaction by adulthood. These data reveal an astrocytic role for developmental Wnt/β-catenin signaling in restricting excitatory synapse numbers and regulating adult social behavior

    Influence of the Milling Conditions of Aluminium Alloy 2017A on the Surface Roughness

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    The article presents the results and process analysis of the face milling of aluminium alloy 2017A with the CoroMill 490 tool on an AVIA VMC 800 vertical milling centre. The study analysed the effects of the cutting speed, the feed rate, the actual number of teeth involved in the process, the minimum thickness of the cut layer (hmin), and the relative displacement in the tool-workpiece system D(ξ) on the surface roughness parameter Ra. To measure relative displacement, an original bench was used with an XL-80 laser interferometer. The analysis of relative displacement and surface roughness allowed these factors to be correlated with each other. The purpose of this article is to determine the stable operating ranges of the CoroMill 490-050Q22-08M milling head with respect to the value of the generated relative displacement w during the face-milling process and to determine its influence on surface roughness. The research methodology presented in this paper and the cutting tests carried out allowed the determination of the optimum operating parameters of the CoroMill 490-050Q22-08M tool during the face milling of aluminium alloy 2017A, which are vc 300 m/m and fz—0.14 mm/tooth. Working with the defined cutting parameters allows all the cutting inserts in the tool body to be involved in shaping the geometrical structure of the surface, while maintaining a low vibration level D(ξ) > 1 µm, a low value of the parameter hmin > 1.5 µm, and the desired value of the parameter Ra > 0.2 µ
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