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Wyświetlanie 1-12 z 12
Tytuł:
The sonoanatomy of lumbar erector spinae and its iliac attachment – the potential substrate of the iliac crest pain syndrome, an ultrasound study in healthy subjects
Anatomia ultrasonograficzna lędźwiowej części mięśnia prostownika grzbietu oraz jego przyczepu biodrowego. Możliwe podłoże zespołu bólowego grzebienia biodrowego – badanie ultrasonograficzne u zdrowych osób
Autorzy:
Todorov, Plamen
Nestorova, Rodina
Batalov, Anastas
Powiązania:
https://bibliotekanauki.pl/articles/1033249.pdf
Data publikacji:
2018
Wydawca:
Medical Communications
Tematy:
iliac crest pain syndrome
Opis:
Background: Iliac crest pain syndrome is a regional pain syndrome that has been identified in many patients with low back pain. Based on anatomical studies, it was suggested that the potential substrate of this syndrome might be the enthesis of the erector spinae muscle at the posterior medial iliac crest. As there have been no imaging studies of this important enthesis, our aim was to assess its characteristics by ultrasound. Methods: Erector spinae enthesis was first studied in a cadaver. Then its characteristics were recorded in 25 healthy volunteers (median age: 28.92, SD: 5.31, mean Body Mass Index 22.61, SD: 3.38), with Esaote My Lab 7 machine using linear transducer (4–13 MHz). Results: The cadaver study confirmed the attachment of a substantial part of erector spinae to a well-defined region on the medial posterior iliac crest. The US study in the volunteers consistently showed the entheses as typical hyperechoic fibrillar structures, slightly oblique to the skin in the longitudinal plane and attaching to the iliac crest. In the transverse plane, the entheses were seen as oval, densely dotted structures in contact with the superior edge of posterior superior iliac spine. Their mean thickness (4.9 ± 0.6 and 5.2 ± 0.7 mm longitudinally; 4.3 ± 0.6 and 4.4 ± 0.7 mm transversely), maximum width (16.3 ± 2.8 and 15.7 ± 2.3 mm) and depth (10.8 ± 7.3 and 10.6 ± 6.2 mm) on the left and right side, respectively, as well as their echostructure were recorded and described. Conclusions: The erector spinae entheses could be assessed in detail by ultrasound, thus their pathological transformation associated with iliac crest pain syndrome could be identified.
Wprowadzenie: Zespół bólowy grzebienia biodrowego jest często rozpoznawany u pacjentów z bólem okolicy lędźwiowo-krzyżowej. Na podstawie badań anatomicznych wysunięto hipotezę, że podłożem tego zespołu może być przyczep mięśnia prostownika grzbietu do tylno-środkowej części grzebienia biodrowego. Ponieważ dotychczas nie przeprowadzono badań obrazowych tej ważnej entezy, naszym celem była ocena jej charakterystycznych cech w badaniu ultrasonograficznym. Metoda: Przyczep mięśnia prostownika grzbietu zbadano najpierw na zwłokach. Następnie uzyskano jego obrazy ultrasonograficzne u 25 zdrowych ochotników (mediana wieku: 28,92, OS: 5,31; średnie BMI: 22,61, OS: 3,38) za pomocą aparatu Esaote MyLab 7, przy użyciu głowicy liniowej (4–13 MHz). Wyniki: Badanie na zwłokach potwierdziło lokalizację przyczepu istotnej części mięśnia prostownika grzbietu do wyraźnie określonego obszaru znajdującego się na tylno-środkowej części grzebienia kości biodrowej. Badania ultrasonograficzne wykonane u zdrowych osób każdorazowo uwidoczniały przyczepy jako typowe hiperechogeniczne włókniste struktury, położone nieco skośnie w stosunku do skóry w przekroju podłużnym, łączące się z grzebieniem kości biodrowej. W przekroju poprzecznym przyczepy były widoczne jako owalne, drobnopunktowe struktury stykające się z górną krawędzią kolca biodrowego tylnego górnego. Odnotowywano, odpowiednio po stronie lewej i prawej, ich średnią grubość (4,9 ± 0,6 oraz 5,2 ± 0,7 mm w przekroju podłużnym; 4,3 ± 0,6 oraz 4,4 ± 0,7 mm w przekroju poprzecznym), maksymalną szerokość (16,3 ± 2,8 oraz 15,7 ± 2,3 mm) oraz głębokość (10,8 ± 7,3 oraz 10,6 ± 6,2 mm), jak również opisywano ich echostrukturę. Wnioski: Szczegółowa ocena ultrasonograficzna przyczepów mięśnia prostownika grzbietu może pozwolić na rozpoznawanie patologii tej struktury będących przyczyną zespołu bólowego grzebienia biodrowego. Artykuł w wersji polskojęzycznej jest dostępny na stronie http://jultrason.pl/index.php/wydawnictwa/volume-18-no-72
Źródło:
Journal of Ultrasonography; 2018, 18, 72; 16-21
2451-070X
Pojawia się w:
Journal of Ultrasonography
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardware Accelerated Simulation of Crest Factor Reduction Block for Mobile Telecommunications
Autorzy:
Nikodem, M.
Kępa, K.
Powiązania:
https://bibliotekanauki.pl/articles/226366.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
crest factor reduction
configurable hardware
hardware acceleration
FPGA
telecommunications
Opis:
This paper reports results of the hardware accelerated simulations of the crest factor reduction (CFR) block which is a common element of the radio signal processing path in base stations for mobile telecommunications. Presented approach increases productivity of radio system architects by shortening the time of model architecture evaluation. This enables unprecedented scale of CFR parameter optimization which requires thousands of simulation runs. We use FPGA device and Xilinx System Generator for DSP technology in order to model CFR block in MATLAB/Simulink environment, implement the accelerator and use it for mixed hardware-software simulation. Reported approach reduces simulation time by 70%, provides straight forward use of fixed-point arithmetic and lowers power consumption by 73% at the cost of constant and relatively low overhead on model development.
Źródło:
International Journal of Electronics and Telecommunications; 2012, 58, 4; 363-368
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expression of cellular retinoic acid-binding protein I and II (CRABP I and II) in embryonic mouse hearts treated with retinoic acid
Autorzy:
Stachurska, Emilia
Loboda, Agnieszka
Niderla-Bielińska, Justyna
Szperl, Małgorzata
Juszyński, Michał
Jozkowicz, Alicja
Dulak, Jozef
Ratajska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/1039942.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
CRABP I
embryonic mouse heart
CRABP II
retinoic acid
neural crest
Opis:
Cellular retinoic acid binding proteins are considered to be involved in retinoic acid (RA) signaling pathways. Our aim was to compare the expression and localization of cellular retinoic acid binding proteins I and II (CRABP I and II) in embryonic mouse hearts during normal development and after a single teratogenic dose of RA. Techniques such as real-time PCR, RT-PCR, Western blots and immunostaining were employed to examine hearts from embryos at 9-17 dpc. RA treatment at 8.5dpc affects production of CRABP I and II in the heart in the 48-h period. Changes in expression of mRNA for retinaldehyde dehydrogenase II (Raldh2), Crabp1 and Crabp2 genes also occur within the same time window (i.e. 10-11dpc) after RA treatment. In the embryonic control heart these proteins are localized in groups of cells within the outflow tract (OT), and the atrioventricular endocardial cushions. A gradient of labeling is observed with CRABP II but not for CRABP I along the myocardium of the looped heart at 11 dpc; this gradient is abolished in hearts treated with RA, whereas an increase of RALDH2 staining has been observed at 10 dpc in RA-treated hearts. Some populations of endocardial endothelial cells were intensively stained with anti-CRABP II whereas CRABP I was negative in these structures. These results suggest that CRABP I and II are independently regulated during heart development, playing different roles in RA signaling, essential for early remodeling of the heart tube and alignment of the great arteries to their respective ventricles.
Źródło:
Acta Biochimica Polonica; 2011, 58, 1; 19-29
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Calculations with a Multi-layer Model of Mixed Sand Transport Against Measurements in Wave Motion and Steady Flow
Autorzy:
Kaczmarek, Leszek M.
Radosz, Iwona
Zawisza, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/2069944.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
wave motion
steady flow
sediment transport
transport
wave trough
wave crest
Opis:
A multi-layer model is used to calculate time-dependent sediment velocity and concentration vertical profiles. This model, in which the differences in sediment transport at different distances from the bed are considered is intended both for the wave motion and steady flow. Numerical calculations were carried out for sediment transport during the wave crest and trough and total sediment transport as a sum of their absolute values. The model concept of variation in shear stress from the skin stress value above the bed to the stress value at the bed previously proposed for steady flow is extended here for the wave motion and verified by direct stress measurements. The calculations were carried out for mixed sand sediments with different grain size distributions including semi-uniform and poorly sorted grains. Comparison with the available small- and large -scale data from flumes and oscillating tunnels yields agreement typically within plus/minus a factor two of measurements.
Źródło:
Rocznik Ochrona Środowiska; 2021, 23; 629--641
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pollution load assessment in the form of TSS and COD emitted from an urbanized catchment in the aspect of administrative pollutant discharge fees on the example of the activity of the J1 CSO in Lodz (Poland)
Autorzy:
Brzezińska, Agnieszka
Wiankowski, Lukasz
Powiązania:
https://bibliotekanauki.pl/articles/27310135.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
environmental engineering
CSO management
sewer system
weir crest level
environmental pollutant discharge fees
Opis:
The article presents the possibility of reducing fees for wastewater discharge from combined sewer overflows (CSOs) into the aquatic environment by minimizing the load emission of total suspended solids (TSS) and chemical oxygen demand (COD). The analysis was conducted based on limiting the wastewater volume discharged to the receiving water by one of the viable options, i.e., raising the overflow crest. The assessment was made on the example of the functioning J1 CSO in Lodz (in Polish: Łódź) in the years 2013–2015. An analysis of rainfall recorded in the J1 catchment area was also performed for this period. For the determination of the TSS and COD load emitted to the receiver, a predictive model based on rainfall parameters and the volume of discharged wastewater was used. To determine the wastewater volume emitted during individual activations of the J1 overflow, the model of the sewer network serving this catchment was calibrated in the EPA SWMM software. Simulations were conducted, considering different heights of the weir crest (static change). The results of the analyzes showed that raising the crest by 5 cm reduced the total fee for the J1 activity by 35% compared to its existing height in 2013 and about 40% for 2015. Raising the crest by 10 cm in 2015 enabled, for example, the J1 overflow activity to be in accordance with the applicable law. Reducing the amount of wastewater discharged to the receiver by using the overflow crest height adjustment method presented in the article may bring measurable financial and ecological benefits.
Źródło:
Geology, Geophysics and Environment; 2023, 49, 4; 375--387
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental Flood Protection Dikes
Autorzy:
Ganiron Jr., Tomas U.
Powiązania:
https://bibliotekanauki.pl/articles/1113827.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Backwater
dike
dike crest
expressway dike
flood
flood level
freeboard
lakeshore
landslide
seepage
Opis:
Flooding is a natural event that replenishes the groundwater and revitalizes the soil through the deposit of sediments. However, when communities settle within floodplains, flooding can cause adverse social, economic and environmental impacts. Flood protection works, such as dikes, can further reduce flood risk. These structures particularly relevant in protecting historic communities that were settled before floodplain management policies were implemented. However, it is technically and economically impossible to completely eliminate flood risk with dikes. During severe floods, dike failures may occur due to erosion, overtopping or seepage. This study predicts that dike construction may lead to water level lowering for in-bank flows and to water level increases for out-of-bank (flood) flows. This confirms that, in principle, the existing Pampanga dike and specifically on the construction of Taguig City dike along the Laguna Lake may have contributed to the observed flood water level trends in the Metro Manila.
Źródło:
World News of Natural Sciences; 2017, 13; 82-100
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Cretaceous crest-bearing shrimps from the Sahel Alma Lagerstatte of Lebanon
Autorzy:
Audo, D.
Charbonnier, S.
Powiązania:
https://bibliotekanauki.pl/articles/20885.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Late Cretaceous
crest-bearing shrimp
Arthropoda
Crustacea
Decapoda
Lagerstatte
Cretaceous
Santonian
Sahel Alma
Lebanon
Opis:
Decapod crustaceans are the most diverse group of fossil invertebrates from the Upper Cretaceous Sahel Alma Lagerstätte (Lebanon, Middle East). They are mainly represented by abundant crest−bearing shrimps which were first described as Penaeus libanensis. We review this species applying the new systematic nomenclature and we propose a more complete description based on 54 unpublished specimens. This review leads to the erection of Palaeobenthesicymus gen. nov. and to the new combination Palaeobenthesicymus libanensis that is the oldest record of the family Benthesicymidae. A neotype is herein designated. Detailed comparisons with extant analogues suggest that the crest bearing shrimps inhabited relatively deep water settings most probably exceeding 150 m, at the transition between the lower circalittoral and the upper bathyal zones, under dysphotic or aphotic conditions.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DAC testing using impulse signals
Autorzy:
Vedral, J.
Fexa, P.
Powiązania:
https://bibliotekanauki.pl/articles/221597.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DAC
ENOB
SINAD
FFT test
Crest Factor
Damped Sine Wave
SINC signal
Multi-Tone signal
Opis:
The Multi-Tone (MT) signal with uniform amplitudes can be used for DAC testing. This paper shows an easier way to generate a MT signal using several impulse signals. The article also analyzes qualities of methods for testing the dynamic parameters of Digital to Analog Converters using an impulse signal. The MT, Damped Sine Wave (DSW) and Sinx/x (SINC) signals will be used as the source for these tests. The Effective Number of Bits (ENOB) and Signal to noise and distortion (SINAD) are evaluated in the frequency domain and they are modified using the Crest Factor (CF) correction and compared with the standard results of the Sine Wave FFT test. The first advantage of the test using an impulse signal is that you need fewer input parameters to create the band signal for testing the DAC. The second one is to reduce the testing time using a band signal in comparison with multiple tests using a single sine wave.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 105-114
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Suitable Spreading Sequences for Asynchronous MC-CDMA Systems
Autorzy:
Addad, M.
Djebbari, A.
Powiązania:
https://bibliotekanauki.pl/articles/307793.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
BER
crest factor
multiple access interference
MC-CDMA
peak-to-average power ratio
zero correlation zone
Opis:
In order to meet the demand of high data rate transmission with good quality maintained, the multi-carrier code division multiple access (MC-CDMA) technology is considered for the next generation wireless communication systems. However, their high crest factor (CF) is one of the major drawbacks of multi-carrier transmission systems. Thus, CF reduction is one of the most important research areas in MC-CDMA systems. In addition, asynchronous MC-CDMA suffers from the effect of multiple access interference (MAI), caused by all users active in the system. Degradation of the system’s bit error rate (BER) caused by MAI must be taken into consideration as well. The aim of this paper is to provide a comparative study on the enhancement of performance of an MC-CDMA system. The spreading sequences used in CDMA play an important role in CF and interference reduction. Hence, spreading sequences should be selected to simultaneously ensure low CF and low BER values. Therefore, the effect that correlation properties of sequences exert on CF values is investigated in this study. Furthermore, a numerical BER evaluation, as a function of the signal-to-noise ratio (SNR) and the number of users, is provided. The results obtained indicate that a trade-off between the two criteria is necessary to ensure good performance. It was concluded that zero correlation zone (ZCZ) sequences are the most suitable spreading sequences as far as the satisfaction of the above criteria is concerned.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 3; 9-13
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DAC testing using modulated signals
Autorzy:
Fexa, P.
Verdal, J.
Svatoš, J.
Powiązania:
https://bibliotekanauki.pl/articles/220431.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
digital-to-analog converter
ENOB
Signal-to-noise and distortion - SINAD
FFT analysis
Crest Factor (CF)
Opis:
This document analyses qualities of methods used for testing dynamical parameters of Digital-to-Analog Converters (DAC) using a multi-frequency signal. As the source for these signals, Amplitude Modulated (AM) and Frequency Modulated (FM) signals are used. These signals are often used in radio engineering. Results of the tests, like Effective Number of Bits (ENOB), Signal-to-Noise and Distortion (SINAD), are evaluated in the frequency domain and they are compared with standard results of Sine Wave FFT test methods. The aim of this research is firstly to test whether it is possible to test a DAC using modulated signals, secondly to reduce testing time, while estimating band performance of DAC.
Źródło:
Metrology and Measurement Systems; 2011, 18, 2; 283-293
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the biotope quality unfavourable to ichthyofauna of the Szczecin Lagoon during the flood crest outflow in summer 1997
Niekorzystne dla ichtiofauny zmiany jakości biotopu toni wodnej Zalewu Szczecińskiego podczas spływu wód powodziowych latem 1997 roku
Autorzy:
Poleszczuk, G.
Powiązania:
https://bibliotekanauki.pl/articles/85133.pdf
Data publikacji:
2003
Wydawca:
Akademia Pomorska w Słupsku
Tematy:
biotope change
biotope quality
water quality
Odra estuary
fish
ichthyofauna
Szczecin Lagoon
flood crest outflow
summer
fish habitat
Źródło:
Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline; 2003, 06
1643-0115
Pojawia się w:
Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bearing estimation using double frequency reassignment for a linear passive array
Autorzy:
Czarnecki, K.
Leśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/260131.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
direction of arrival
DOA
instantaneous frequency
short-time Fourier transform
STFT
time-frequency reassignment
intercept and surveillance sonar
crest factor
Opis:
The paper demonstrates the use of frequency reassignment for bearing estimation. For this task, signals derived from a linear equispaced passive array are used. The presented method makes use of Fourier transformation based spatial spectrum estimation. It is further developed through the application of two-dimensional reassignment, which leads to obtaining highly concentrated energy distributions in the joint frequency-angle domain and sharp graphical imaging. The introduced method can be used for analysing, a priori, unknown signals of broadband, nonstationary, and/or multicomponent type. For such signals, the direction of arrival is obtained based upon the marginal energy distribution in the angle domain, through searching for arguments of its maxima. In the paper, bearing estimation of three popular types of sonar pulses, including linear and hyperbolic frequency modulated pulses, as well as no frequency modulation at all, is considered. The results of numerical experiments performed in the presence of additive white Gaussian noise are presented and compared to conventional digital sum-delay beamforming performed in the time domain. The root-mean-square error and the peak-to-average power ratio, also known as the crest factor, are introduced in order to estimate, respectively, the accuracy of the methods and the sharpness of the obtained energy distributions in the angle domain.
Źródło:
Polish Maritime Research; 2017, 3; 26-35
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
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