16 research outputs found
Nesfatin-1, a unique regulatory neuropeptide of the brain
Nesfatin-1, a newly discovered NUCB2-derived satiety neuropeptide is expressed in several neurons of forebrain, hindbrain, brainstem and spinal cord. This novel anorexigenic substance seems to play an important role in hypothalamic pathways regulating food intake and energy homeostasis. Nesfatin-1 immunoreactive cells are detectable in arcuate (ARC), paraventricular (PVN) and supraoptic nuclei (SON), where the peptide is colocalized with POMC/CART, NPY, oxytocin and vasopressin. The nesfatin-1 molecule interacts with a G-protein coupled receptor and its cytophysiological effect depends on inhibitory hyperpolarization of NPY/AgRP neurons in ARC and melanocortin signaling in PVN. Administration of nesfatin-1 significantly inhibits consumatory behavior and decreases weight gain in experimental animals. These recent findings suggest the evidence for nesfatin-1 involvement in other important brain functions such as reproduction, sleep, cognition and anxiety- or stress-related responses. The neuroprotective and antiapoptotic properties of nesfatin-1 were also reported. From the clinical viewpoint it should be noteworthy, that the serum concentration of nesfatin-1 may be a sensitive marker of epileptic seizures. However, the details of nesfatin-1 physiology ought to be clarified, and it may be considered suitable in the future, as a potential drug in the pharmacotherapy of obesity, especially in patients treated with antipsychotics and antidepressants. On the other hand, some putative nesfatin-1 antagonists may improve eating disorders. (C) 2011 Elsevier Ltd. All rights reserved
A new prototype of piezoelectric bending resonant transducer for analysis of soft tissues properties
This paper is devoted to a new piezoelectric bending resonant transducer prototype dedicated to the characterization of the mechanical properties of soft tissue. A general description of the actuator’s structure is presented including the basic principles of the measurement. The chosen geometry of the prototype is discussed and compared with the existing version. Constitutive equations are presented for the active and passive layer of the cantilever transducer. The prototype is verified by means of finite element method analysis. Results of the static and modal analysis are presented and discussed
Measurements of insulation resistance of electric motors
W artykule podano zasady wykonywania pomiarów rezystancji izolacji maszyn elektrycznych. Przedstawiono dostępne w literaturze temperaturowe współczynniki korekcyjne konieczne do przeliczania zmierzonych wartości rezystancji na wartość występującą w temperaturze odniesienia. Obserwowane różnice współczynników temperaturowych wynikają z rodzaju zastosowanego materiału izolacji, konstrukcji silnika oraz technologii impregnowania uzwojeń.The paper presents principles for insulation resistance measurements of electric motors. The temperature correction coefficients available in the literature to converting the measured resistance value into a value occurring at the reference temperature were analyzed. Occurred differences of temperature coefficients results from the insulation type, construction of the motor and winding impregnation technology
Maszyny elektryczne wokół nas. Zastosowanie, budowa, modelowanie, charakterystyki, projektowanie
Development and performance analysis of a novel multiphase doubly-fed induction generator
This paper presents the research into the design and performance analysis of a novel five-phase doubly-fed induction generator (DFIG). The designed DFIG is developed based on standard induction motor components and equipped with a five-phase rotor winding supplied from the five-phase inverter. This approach allows the machine to be both efficient and reliable due to the ability of the five-phase rotor winding to operate during single or dual-phase failure. The paper presents the newly designed DFIG validation and verification based on the finite element analysis (FEA) and laboratory tests
Remote monitoring system for the working parameters of a wind turbine with vertical axis
W artykule przedstawiono układ do zdalnego monitorowania parametrów pracy elektrowni wiatrowej o pionowej osi obrotu. Do budowy systemu wykorzystano mikrokomputer klasy Raspberry PI 3 z zainstalowanym systemem operacyjnym Raspbian oraz kartę pomiarową MicroDAQ E2000. Opracowany system umożliwia monitorowanie mocy na wyjściu generatora, momentu na wale turbiny, prędkości obrotowej turbiny oraz prędkości wiatru. Wartości monitorowanych parametrów zapisywane są w pamięci karty pomiarowej. Dzięki zastosowaniu mikrokomputera możliwe było podłączenie komputera zewnętrznego do systemu i przesyłanie zapisanych danych oraz monitorowanie ich wartości online.The article presents a system for remote monitoring of working parameters of a wind turbine with vertical axis. The system was built using a Raspberry PI 3 microcomputer with the Raspbian operating system and a MicroDAQ E2000 measuring card. The developed system enables monitoring the power output of the generator, torque on the turbine shaft, turbine speed and wind speed. The values of the monitored parameters are saved in the memory of the measuring card. Due to the use of a microcomputer, it is possible to connect an external computer to the system and send saved data and monitor their value online
Mechanical-Level Hardware-In-The-Loop and Simulation in Validation Testing of Prototype Tower Crane Drives
In this paper, the static and dynamic simulations, and mechanical-level Hardware-In-the-Loop (MHIL) laboratory testing methodology of prototype drive systems with energy-saving permanent-magnet electric motors, intended for use in modern construction cranes is proposed and described. This research was aimed at designing and constructing a new type of tower crane by Krupiński Cranes Company. The described research stage was necessary for validation of the selection of the drive system elements and confirmation of its compliance with applicable standards. The mechanical construction of the crane was not completed and unavailable at the time of testing. A verification of drive system parameters had to be performed in MHIL laboratory testing, in which it would be possible to simulate torque acting on the motor shaft. It was shown that the HIL simulation for a crane may be accurate and an effective approach in the development phase. The experimental tests of selected operating cycles of prototype crane drives were carried out. Experimental research was performed in the LINTE^2 laboratory of the Gdańsk University of Technology (Poland), where the MHIL simulator was developed. The most important component of the system was the dynamometer and its control system. Specialized software to control the dynamometer and to emulate the load subjected to the crane was developed. A series of tests related to electric motor environmental parameters was carried out
Type of residence (house) among donators (n = 244).
<p>Type of residence (house) among donators (n = 244).</p
“<i>Mortui Vivos Docent</i>” or Who Gives His Body to Science? The Analysis of the Personal Questionnaires of Polish Donors in the Conscious Body Donation Program
<div><p>The Conscious Body Donation Program conducted since 2003 by the Department of Human Anatomy, Medical University of Silesia in Katowice was the first innovative project aimed at obtaining informed donors' bodies for the purpose of teaching anatomy in Poland. The aim of this prospective study was to determine the declared donors' characteristics and to establish the possible motivation for body donation. A total of 244 application files were reviewed and the following information was analyzed: donor’s age, age at which the decision to donate the body was made, donor’s place of residence and declared nationality, family background, education and profession, family structure and religion. Our results showed that mainly elderly people decided to donate their bodies (68.5 ± 11.84 years), living mostly in large and medium-sized cities. Men - donors often lived in small towns. Most of the donors were of blue-collar parentage, completed secondary education and at the time of taking decision to donate where married and retired. Widows were more likely to make the decision to donate than widowers. Most of our donors were Catholic. Our analysis of the profile of Polish donors may be useful to understand better for which groups of people death is not to be perceived as the end, and may become a value, which can be beneficial to living people.</p></div