Anatomically-based skeleton kinetics and pose estimation in freely-moving rodents

Forming a complete picture of the relationship between neural activity and body kinetics requires quantification of skeletal joint biomechanics during behavior. However, without detailed knowledge of the underlying skeletal motion, inferring joint kinetics from surface tracking approaches is difficult, especially for animals where the relationship between surface anatomy and skeleton changes during motion. Here we developed a videography-based method enabling detailed three-dimensional kinetic quantification of an anatomically defined skeleton in untethered freely-behaving animals. This skeleton-based model has been constrained by anatomical principles and joint motion limits and provided skeletal pose estimates for a range of rodent sizes, even when limbs were occluded. Model-inferred joint kinetics for both gait and gap-crossing behaviors were verified by direct measurement of limb placement, showing that complex decision-making behaviors can be accurately reconstructed at the level of skeletal kinetics using our anatomically constrained model

Estimation of skeletal kinematics in freely moving rodents

Forming a complete picture of the relationship between neural activity and skeletal kinematics requires quantification of skeletal joint biomechanics during free behavior; however, without detailed knowledge of the underlying skeletal motion, inferring limb kinematics using surface-tracking approaches is difficult, especially for animals where the relationship between the surface and underlying skeleton changes during motion. Here we developed a videography-based method enabling detailed three-dimensional kinematic quantification of an anatomically defined skeleton in untethered freely behaving rats and mice. This skeleton-based model was constrained using anatomical principles and joint motion limits and provided skeletal pose estimates for a range of body sizes, even when limbs were occluded. Model-inferred limb positions and joint kinematics during gait and gap-crossing behaviors were verified by direct measurement of either limb placement or limb kinematics using inertial measurement units. Together we show that complex decision-making behaviors can be accurately reconstructed at the level of skeletal kinematics using our anatomically constrained model

Experimental Stand for Investigations of Insulator Degradation and Electrode Erosion in High-current Breaker

An experimental stand for studies of electric arc, electrode erosion and insulator degradation processes in high-current circuit breakers and some preliminary experimental data is described. The setup includes a discharge chamber, a capacitive energy storage with capacitance of 0.11 F, voltage up to 10 kV, and all necessary diagnostic techniques. The stand is designed for modeling current pulse with amplitude of 3–150 kA and duration of the first half period of 1.0–3.0  ms during the process of disconnecting the ring and the pin contacts. The arc is cooled by transverse gas blowing at pressure in the chamber of 0.5–3 MPa. Acquired experimental data can be used for verification of the modelling results of the heat transfer processes in the discharge chamber. At the stand, advanced composite materials based on carbon and iron-copper pseudoalloy are studied

Diversity management in organization

Zarządzanie różnorodnością jest strategią zarządzania stosunkowo nową. Mimo licznych rozważań nadal w większym stopniu pozostaje koncepcją teoretyczną niż programem działań praktycznych. Jak każda koncepcja ma zarówno swoich zwolenników, jak i krytyków. Nawet jeżeli przyjmiemy, że krytyka ta jest w pewnym stopniu zasadna, warto zwrócić uwagę, że wymienionych wcześniej zalet i korzyści wynikających z zarządzania różnorodnością jest zdecydowanie więcej niż ewentualnych wad. Obecnie podkreśla się, że zarządzanie różnorodnością może przynieść organizacji wiele korzyści nie tylko w wymiarach instytucjonalnym i ekonomicznym, lecz także społecznym.Diversity management is a relatively new management strategy. Despite numerous considerations of this subject it still remains rather a theoretical conception than a practical actions programme. As every conception it has its supporters and critics. Even if we assume that the critic is to a certain degree justified, it is worth noting that there are definitely more above mentioned advantages and benefits resulting from the diversity management than the possible disadvantages. Nowadays it is emphasized that the diversity management may bring a lot of benefits to the organization, not only in institutional and economic dimensions but also social one

The Human Relation to Animals and the Idea of the Sustainable Development

Stosunek do zwierząt nie jest jedynym, ani najważniejszym czynnikiem charakteryzującym współczesnego człowieka. Jest jednak na tyle istotny, że od kilkudziesięciu lat przykuwa uwagę rosnącego grona naukowcow, specjalistów różnych dziedzin, działaczy społecznych i zwykłych ludzi. Powinien zatem być w większym stopniu wyartykułowany w koncepcji zrównoważonego rozwoju. Celem artykułu jest przedstawienie najbardziej charakterystycznych relacji zachodzących między człowiekiem i zwierzęciem dawniej i obecnie oraz zastanowienie się, w jakim kierunku relacje te mogą zmieniać się w przyszłości dalekiej i bliskiej.The connection between the human and animals is neither the only nor the most important factor typical for the contemporary people. However, it is essential that for some decades it has been focusing attention of growing group of scientists and specialists of different fields, social workers and common people. Therefore, it should be stronger articulated in the conception of sustainable development. The aim of this article is to show the most characteristic relations between people and animals

Motor and language deficits correlate with resting state functional magnetic resonance imaging networks in patients with brain tumors

Background and purpose Evidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor. Materials and methods Sixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n = 49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n = 29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA). Results Motor group: paretic patients showed significantly (P = 0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P < 0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r = 0.68, P < 0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P = 0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r = 0.72, P < 0.01) between BA 44 BOLD signal and phonological fluency performance was observed. Conclusions Our results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients

Motor and language deficits correlate with resting state functional magnetic resonance imaging networks in patients with brain tumors

Background and purpose: Evidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor. Materials and methods: Sixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n = 49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n = 29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA). Results: Motor group: paretic patients showed significantly (P = 0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P &lt; 0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r = 0.68, P &lt; 0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P = 0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r = 0.72, P &lt; 0.01) between BA 44 BOLD signal and phonological fluency performance was observed. Conclusions: Our results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients. © 2018 Elsevier Masson SA

Axial Blast Type Discharge Chamber with Moving Electrode

The paper presents some results concerning electrophysical and gas-dynamics parameters of high-curent arc in axial blast discharge chamber. The experimental stand and numerical model were modified for axial gas flow type. Some design changes are described in the paper. The experiments were carried out for gas pressures of 1.0-6.0 MPa with current amplitude of 25-150 kA. The current half-period was of 1.0-10.0 ms. The contacts moved apart to the distance of 3-4 cm due to gas pressure boost in the chamber. OpenFOAM package with the library swak4foam was used for numerical simulation

Calibration kernels with Alternative Sampling Scheme (CASS) for Parallel Imaging: SENSE meets CASS

We developed new calibration kernels with an alternative undersampling scheme (CASS) for parallel imaging to reduce coherent aliasing artifacts and noises. By sampling k-space lines with irregular and blockwise patterns, incoherent aliasing patterns and noise signals were spread in reconstructed CASS images. Noteworthily, the CASS method outperformed the conventional GRAPPA method at higher acceleration factors

Influence of GRAPPA pre-scan methods on temporal SNR of rapid GE-EPI measurements at 9.4 Tesla

Introduction: In functional MRI (fMRI) echo planar imaging (EPI) is often combined with parallel imaging, e.g. GRAPPA (1), to increase temporal resolution. The auto-calibration scans (ACS) required for the calculation of the coil sensitivities in the parallel imaging reconstruction are conventionally acquired in a segmented fashion (number of segments = parallel imaging factor), with the individual segments of each slice separated by the repetition time (TR). However, in case of TRs in the range of several seconds, ACS segments may be acquired at different B0-field offsets e.g. due to respiration or motion. These fluctuations can result in variations in temporal SNR (tSNR) across different slices particularly at high-field (3). The sensitivity of tSNR on physiological effects can be reduced by acquiring all segments of a slice successively with minimum delay in the so called FLEET technique (3). Alternatively, a FLASH readout, which is more robust against B0-field changes, can be used to obtain the ACS data (2). Although physiological influences are usually considered to be the main cause of tSNR variations at long TRs, as far as we know, the performance of various GRAPPA pre-scan methods (conventional, FLEET and FLASH) has not previously been investigated for a TR in the sub-second range. Methods: Four healthy subjects were measured at 9.4 Tesla (Siemens Healthineers, Germany) using an in-house-built 16Tx-31Rx head-coil (4). Gradient-echo EPIs were acquired for two regions covering a major part of the thalamus (ROI 1) and the motor cortex (ROI 2). Imaging parameters: TE/TR = 23/600ms, FA = 40°, 12 slices, 150 volumes. Two different spatial resolutions were used: • 1 x 1 x 2 mm³: mtx = 192x192, 6/8 partial Fourier, GRAPPA = 4 (60 ACS lines), echo spacing = 1.01 ms. • 2 x 2 x 2 mm³: mtx = 96x96, GRAPPA = 3 (45 ACS lines), echo spacing = 0.8 ms. The two protocols were repeated for both ROIs for all three ACS sampling methods: conventional, FLEET, and FLASH. The excitation flip angle for the FLEET and FLASH ACS scans was 10° and 15°, respectively. Temporal SNR maps were calculated as the mean signal value across time divided by its temporal standard deviation. To quantify the tSNR for the different GRAPPA pre-scan methods, mean tSNR values were assessed for each ROI after performing manual brain masking. Results: Figure 1 shows the calculated tSNR for the different GRAPPA pre-scan methods and brain regions in an example volunteer. The lowest tSNR is visible for the data measured with conventional ACS and low spatial resolution in particular. This observation is consistent for both ROIs. Averaged over all slices, the tSNR values in images acquired with FLEET or FLASH ACS sampling are higher than with conventional ordering, too (Figure 2). This is especially the case at low image resolution. At high spatial resolution, the tSNR of data reconstructed using FLEET and FLASH sampled data is almost identical and the improvement compared to the conventional method is rather small (∼12% in ROI 1 and ∼25% in ROI 2). Conclusions: Although physiological influences and respiration effects in particular are expected to be reduced for sub-second TR, the FLEET and FLASH pre-scan methods yielded clearly higher tSNR compared to the conventional approach. One explanation is, that despite the short TR, the acquisition of all ACS lines still took about 1.8 s (2x2x2 mm³) and 2.4 s (1x1x2 mm³), respectively, due to the slice-segment acquisition scheme, whereas the FLEET method only required about 200 ms (1x1x2 mm³). This study also confirmed that the impact of physiological fluctuations on tSNR heavily scales with the spatial resolution, as it is the case for un-accelerated imaging (5). Thus, even though less tSNR improvement can be expected for alternative ACS acquisition techniques at high spatial resolutions, it still has to be considered as a potential source for effect size differences even in sub-second TR fMRI studies