Average Root Mean Square Values Research Articles

Surface electromyography character of upper limb muscle after open reduction combine with ulnar osteotomy in children with neglected Monteggia fracture.

This study aims to investigate the surface electromyography (sEMG) characteristics of upper limb muscles in children with neglected Monteggia fracture after open reduction of radial head dislocation and ulna osteotomy and bone grafting internal fixation, and to understand the recovery of muscle activity in children after operation, provide reference for clinical rehabilitation. A retrospective analysis was conducted on sixteen children with neglected Monteggia fracture who underwent ulna osteotomy at our hospital from January 2021 to August 2022. The biceps brachii, triceps brachii, flexor carpi radialis, and extensor carpi ulnaris muscle activities were recorded during grip strength tests, flexion and extension of elbow joint while holding a 1 kg dumbbell, as well as gripping tasks. The root mean square (RMS) values of sEMG signals, co-contraction ratio, and elbow joint function scores were compared between pre- and post-operation periods as well as between the affected side and unaffected side. The preoperative maximum grip strength, as well as the average RMS values of flexor carpi radialis and average RMS value of extensor carpi ulnaris on the affected side were significantly lower. After surgery, both the maximum RMS value of biceps brachii and maximum and average RMS value of extensor carpi ulnaris on the affected side remained lower. Prior to surgery, when performing elbow flexion and extension tests while holding a 1 kg dumbbell, both mean RMS values of biceps brachii and flexor carpi radialis on the affected side were smaller. However, after surgery, there was an increase in mean RMS values of biceps brachii on the affected side. Furthermore, postoperative elbow function scores were significantly higher than preoperative scores. Open reduction of radial head dislocation combined with ulna osteotomy and bone grafting can achieve good functional activities in the treatment of neglected Monteggia fractures in children. The EMG activity of the extensor carnosus ulnalis muscle on the affected side related to grip strength was low, and the desired effect was not achieved within the expected time.

Evaluation of the effect of orthodontic treatment on the reliability of facial recognition by using three-dimensional model superimposition technique

3D-3D registration of facial models, has great advantages in personal individual identification in forensic medicine. However, orthodontic treatment has brought changes in facial soft and hard tissues, which has a potential effect in personal identification. The aim of the study was to explore whether orthodontic treatment affects 3D-3D facial recognition. A total of 68 patients aged between 18 and 38 were selected (30 subjects with tooth extraction, 38 subjects with non-tooth extraction) and a control group consisting of 30 volunteers without orthodontic treatment was selected from a database of 3dMD facial models. 3dMD facial model acquisition was performed twice for each subject. For both extraction and non-extraction groups, T0 was acquired before treatment, and T1 was acquired at the end of treatment. The time span of 2 times 3dMD facial model acquisition in the control group was about 2 years. 3dMD facial models were then registered onto other 3dMD models belonging to the same and different individuals according to the minimum point-to-point distance, getting a cohort of matches and mismatches. Root mean square (RMS) value of the minimum point-to-point distance between two models was then calculated. The intra- and inter-observer repeatability coefficients were 0.986 (P<0.001) and 0.982 (P<0.001). The absolute technical error of measurement (TEM) value was 0.05 mm and 0.04 mm, and relative technical error of measurement (rTEM) value was 4.91 % and 3.60 %, respectively. Possible significant differences between groups were assessed through independent samples t-test or Mann–Whitney U test (p<0.001). The average RMS value was 1.03±0.33 mm in matches of orthodontic group, 0.67±0.22 mm in matches of control group, and 2.66±0.51 mm in mismatches. An RMS value range of 1.70–1.77 mm could distinguish matches from mismatches in 100 % of cases in the present study. This study showed that orthodontic treatment would not affect 3D-3D facial recognition in adults for the purpose of individual identification in forensic medicine.

Contribution analysis of the addition of laser ranging interferometry on GRACE-FO gravity field estimation under different accelerometer calibration schemes

To investigate the influence of K-Band microwave ranging (KBR) and Laser Ranging Interferometer (LRI) inter-satellite range-rates from the GRACE-FO mission on the recovery of gravity fields, this paper explores two distinct methods for accelerometer scale estimation, namely diagonal matrix parameterization and full matrix parameterization. Integrating both KBR and LRI data from GRACE-FO into gravity field recovery, we have derived six new time series of monthly gravity field solutions based on two different accelerometer calibration approaches, entitled KBRLRI_Com (incorporating both KBR and LRI data), KBR_Only (using pure KBR data), LRI_Only (solely utilizing LRI data) truncate to degree and order 60 over the period from January 2019 to June 2022. Analyses of KBRLRI_Com, KBR_Only, and LRI_Only reveal the following findings: (1) LRI demonstrates significant advantages over KBR in both diagonal and full scale matrix scenarios, across the time and frequency domains, which shows lower root mean square (RMS) values of the post-fit residuals in the time domain and substantially lower noise at higher frequencies; (2) the comparison between KBRLRI_Com, KBR_Only, and LRI_Only in terms of geoid degree error suggests that KBRLRI_Com agrees well with KBR_Only and LRI_Only at the low degrees (below degree 30), while effectively reducing the high-frequency noise, especially when the diagonal scale matrices are employed; the benefit of KBRLRI_Com solution is mainly attributed to the enhanced quantity of ranging observations. (3) by analyzing the signal and noise over the globe, ocean, Australian continent, and Amazon and Ganges river basins, we find that KBRLRI_Com is highly consistent with KBR_Only and LRI_Only in terms of spatial signals, while KBRLRI_Com exhibits less spatial noise; when employing diagonal and full matrices, the noise of gravity field solutions derived by incorporating LRI data is mitigated by 8.8 % and 3.9 % over the global ocean compared to KBR_Only, as well as 7.6 % and 3.2 % in the Australian continent; especially in the diagonal matrix case, the incorporation of LRI measurements for calculating monthly gravity fields results in a more pronounced decrease of spatial noise. (4) in the oceanic region, KBR_Only and LRI_Only have average RMS values of 11.3 cm and 11.6 cm in diagonal matrices, respectively, and 10.2 cm and 11.6 cm in the full matrix, indicating a generally comparable level of accuracy between the two models.

Estimation and analysis of GNSS specific-observation biases using constrained rank-deficient virtual observation algorithm

ABSTRACT This paper initially introduces two algorithms for the constrained rank-deficient indirect adjustment model and validates their equivalence. Subsequently, using DCBs provided by the Chinese Academy of Sciences (CAS) and the German Aerospace Center (DLR) as observed values, and CAS-provided OSBs as reference values, the accuracy of the virtual observation algorithm is verified. The results indicate that the average Root Mean Square (RMS) values between the estimated OSB value obtained based on CAS’s DCB and the reference value is mostly below 0.1 ns. The average RMS values between the OSB estimates derived from DLR’s DCBs for GPS, GLONASS, BDS, and Galileo compared to the reference values are 0.31 ns, 0.37 ns, 0.55 ns, and 0.24 ns, respectively, demonstrating a good level of consistency. This further validates the accuracy of the algorithm.

A Refined Atmospheric Weighted Average Temperature Model Considering Multiple Factors in the Qinghai–Tibet Plateau Region

The Qinghai–Tibet Plateau region has significant altitude fluctuations and complex climate changes. However, the current global weighted average temperature (Tm) model does not fully consider the impact of meteorological and elevation factors on it, resulting in existing models being unable to accurately predict the Tm in the region. Therefore, this study constructed a weighted average temperature refinement model (XTm) related to surface temperature, water vapor pressure, geopotential height, annual variation, and semi-annual variation based on measured data from 13 radiosonde stations in the Qinghai–Tibet Plateau region from 2008 to 2017. Using the Tm calculated via the numerical integration method of radiosonde observations in the Qinghai–Tibet Plateau region from 2018 to 2019 as a reference value, the quality of the XTm model was tested and compared with the Bevis model and GPT2w (global pressure and temperature 2 wet) model. The results show that for 13 modeling stations, the bias and root-mean-square (RMS) values of the XTm model were −0.02 K and 2.83 K, respectively; compared with the Bevis, GPT2-1, and GPT2w-5 models, the quality of XTm was increased by 47%, 38%, and 47%, respectively. For the four non-modeling stations, the average bias and RMS values of the XTm model were 0.58 K and 2.78 K, respectively; compared with the other three Tm models, the RMS values and the mean bias were both minimal. In addition, the XTm model was also used to calculate the global navigation satellite system (GNSS) precipitable water vapor (PWV), and its average values for the theoretical RMSPWV and RMSPWV/PWV generated by water vapor calculation were 0.11 mm and 1.03%, respectively. Therefore, in the Qinghai–Tibet Plateau region, the XTm model could predict more accurate Tm values, which, in turn, is important for water vapor monitoring.

Investigating the Performance of IGS Real-Time Global Ionospheric Maps under Different Solar Conditions

In recent years, real-time global ionospheric map (RT-GIM) products have been actively developed by the international global navigation satellite system (GNSS) service (IGS) and its ionosphere associate analysis centers (IAACs) along with the increase of RT-GNSS multi-frequency and multi-constellation observations. In this study, the accuracy and consistency of three RT-GIM products from the Chinese Academy of Sciences (CAS), Wuhan University (WHU), and IGS are evaluated and analyzed utilizing three validation methods, namely, comparison with JASON-3 vertical total electron content (VTEC), the difference of slant total electron content (dSTEC), and IGS combined final GIM (IGSG) data. The test period was from 1 January 2019 to 31 December 2022, including the different solar activities. First, the comparison with JASON-3 data illustrates that the quality of the three RT-GIM products over oceans is in great consistency with that of the IGSG during different levels of solar activity and the daily mean bias (MEAN) values in low and high solar activities are approximately 5 and 10 TECU, respectively. The root mean square (RMS) values under low and high solar activities can be up to 7 and 12 TECU. Furthermore, the dSTEC validation results present that the MEAN values of RT-GIM products from different IAACs at high- and mid-latitude stations are about 0.5 TECU, which is smaller than those at low-latitude stations at about 1 TECU over continental regions. The standard deviation (STD) and RMS values for various RT-GIM products are within 3 and 4 TECU at low latitudes, respectively. In terms of the comparison with IGSG, the result shows that IGS combined RT-GIM (IRTG) presents better consistency than CAS RT-GIM (CRTG) and WHU RT-GIM (WRTG) in 2021 and 2022, with average annual STD and RMS values of 2.56 and 2.78 TECU, respectively. The daily biases of the RT-GIM products relative to IGSG can reach 4 TECU in high solar activities and the daily STD and RMS values are mainly within the 5 to 6 TECU range, respectively.

Validation and evaluation on B1IB3I-based and B1CB2a-based BDS-3 precise orbits from iGMAS

The quality analysis of precise orbit products are important for the BeiDou global navigation satellite system (BDS-3) to provide precise positioning, navigation and timing (PNT) services to users. The International GNSS Monitoring and Assessment System (iGMAS) is simultaneously been provided with B1IB3I-based and B1CB2a-based BDS-3 precise orbits since September 29, 2019. However, a comprehensive comparison and analysis of these two types of orbit products is still missing. In this contribution, we study the performance of these precise orbits by analyzing the day boundary discontinuity and Satellite Laser Ranging (SLR). Moreover, we compare these precise orbits with the BDS-3 orbit products from the multi-GNSS Experiment (MGEX) analysis center. The test period is more than two years from September 29, 2019 to October 21, 2021. We found that: First, compare them with the MGEX BDS-3 precise orbits provided by GFZ and WHU, the average root mean square (RMS) value of the position deviation in the 3D directions orbit component is 0.081 ∼ 0.154 m for MEO satellites and 0.202 ∼ 0.255 m for IGSO satellites. The ranks of different BDS-3 orbit consistency are MEO SECM > MEO CAST > IGSO and we observe that the orbit consistency in eclipse period is better than the ones in non-eclipse period expect for rare cases; Secondly, the RMS of SLR residuals is 5.0 ∼ 6.0 cm, and compared to the orbit in non-eclipse period, the decrease of orbit in eclipse period in percentage is 1.72%∼8.00%. In addition, the radial performance of B1IB3I-based precise orbits for MEO CAST satellites is better than that of B1CB2a-based precise orbits, but it is opposite for MEO SECM satellites; Thirdly, combine with the CODE’s new solar radiation pressure model, namely ECOM2, by using the day boundary discontinuity, the preliminary results illustrate that the average RMS value of the day boundary discontinuity for BDS-3 MEO satellites in the 3D directions orbit component is 0.546 ∼ 0.639 m, and it is 0.881 ∼ 0.897 m for BDS-3 IGSO satellites. The performance ranking of day boundary discontinuity of BDS-3 precise orbits in the 3D directions orbit component is B1IB3I-based MEO CAST > B1IB3I-based MEO SECM > B1CB2a-based MEO CAST > B1CB2a-based MEO SECM > B1CB2a-based IGSO > B1IB3I-based IGSO satellites.

Analysis of BDS-3 PPP-B2b Positioning and Time Transfer Service

With the completion of the BeiDou global navigation satellite system (BDS-3), the BeiDou Navigation Satellite System Signal In Space Interface Control Document Precise Point Positioning Service Signal PPP-B2b (Version 1.0) was officially announced, and BDS-3 officially broadcast PPP-B2b correction to broadcast ephemeris through geostationary earth orbit (GEO) satellites to provide precise point positioning services for users in the Asia–Pacific region. This study comprehensively analyzes the application of the PPP-B2b product to time transfer and positioning. On a daily basis, the PPP-B2b positioning accuracy after convergence is calculated using the four ionosphere-free (IF) combinations in static and simulated kinematic modes: BDS B1I/B3I, BDS B1C/B2a, BDS B1I/B3I + GPS, and BDS B1C/B2a + GPS. Observations of time laboratories including the National Time Service Center of the Chinese Academy of Sciences (NTSC) and the Telecommunication Laboratories (TL) are employed to conduct zero-baseline common clock difference (CCD) time comparison experiments and long-baseline time comparison experiments using the PPP-B2b product and the GBM product. The results indicate that the PPP-B2b position accuracy in static mode by only BDS is 1.5/2.7/3.9 cm, and by GPS + BDS is within 1.5/2.5/3.5 cm in North, East, and Up directions, respectively. Regarding simulated kinematic PPP-B2b, the average root mean square (RMS) values of the position errors in the North, East, and Up directions for the combination of BDS B1I/B3I + GPS and BDS B1I/B3I are 3.4/5.8/7.6 cm and 3.8/6.6/7.8 cm, respectively. Simultaneously, the average RMS values of position errors using BDS B1C/B2a + GPS and BDS B1C/B2a are 3.6/4.9/8.1 cm and 4/6.1/8.5 cm. In the time comparison study, the results of zero-baseline CCD using the PPP-B2b product and the GBM product are within the fluctuation range of 0.1 ns, respectively. Particularly, the long-baseline time comparison difference between results employing the PPP-B2b product and the GBM product is within the range of ±0.5 ns.

Accuracy evaluation of surface registration algorithm using normal distribution transform in stereotactic body radiotherapy/radiosurgery: A phantom study

PurposeTo evaluate a feasibility of normal distribution transform (NDT) algorithm compared with the iterative closest point (ICP) method as a useful surface registration in stereotactic body radiotherapy (SBRT)/stereotactic radiosurgery (SRS).MethodsPoint cloud images using the 3D triangulation technology were obtained from a depth camera‐based optical imaging (OSI) system equipped in a radiosurgery room. Two surface registration algorithms, NDT and ICP, were used to measure and compare the discrepancy values between the reference and the current surfaces during the positioning of the patient. The performance evaluation was investigated by calculating the registration error and root‐mean‐square (RMS) values for the surface model, reposition, and target accuracy, which were analyzed statistically using a paired t‐test.ResultsFor surface model accuracy, the average of the registration error and RMS values were measured as 3.56 ± 2.20 mm and 6.98 ± 1.89 mm for ICP method, and 1.76 ± 1.32 mm and 3.58 ± 1.30 mm for NDT method (p < 0.05). For reposition accuracy, the average registration error and RMS values were calculated as 1.41 ± 0.98 mm and 2.53 ± 1.64 mm using ICP method, and 0.92 ± 0.61 mm and 1.75 ± 0.80 mm using NDT method (p = 0.005). The overall target accuracy using the NDT method reduced the average of the reposition error and overall RMS value by 0.71 and 1.32 mm, respectively, compared to the ICP method (p = 0.03).ConclusionsWe found that the surface registration algorithm based on NDT method provides more reliable accuracy in the values of surface model, reposition, and target accuracies than the classic ICP method. The NDT method in OSI systems offers reasonable accuracy in SBRT/SRS.

3D Digital Evaluation for Direct Composite Restoration Using the Modified Stamp Technique.

To evaluate the clinical performance of direct composite restorations using the modified stamp technique (MST) in vivo. A total of 30 posterior teeth with undermining caries were randomly divided into two groups and then restored using the MST and conventional technique (CT), respectively. 3D images of the occlusal surface were obtained using an intraoral scanner (CEREC Omnicam, Dentsply Sirona, Charlotte, NC, USA) before and after treatment and the differences between these two 3D images were analysed with reverse engineering software. Statistical analysis was performed using a one-way analysis of variance (ANOVA) combined with a least significant difference (LSD) post hoc test using SPSS 20.0 software (IBM, Armonk, NY, USA). The statistical analysis revealed that the average root mean square (RMS) values of best fit alignment errors were significantly different between groups (P < 0.01). The average RMS values in the MST and CT groups were 0.0738 ± 0.0279 and 0.1638 ± 0.0682, respectively. The LSD post hoc test revealed that the value was significant smaller in the MST group than in the CT group. The MST was effective in direct composite restoration. The morphological consistency of the occlusal surface using the MST was better than with the CT.

Modeling and Performance Evaluation of Precise Positioning and Time-Frequency Transfer with Galileo Five-Frequency Observations

The present Global Navigation Satellite System (GNSS) can provide at least double-frequency observations, and especially the Galileo Navigation Satellite System (Galileo) can provide five-frequency observations for all constellation satellites. In this contribution, precision point positioning (PPP) models with Galileo E1, E5a, E5b, E5 and E6 frequency observations are established, including a dual-frequency (DF) ionospheric-free (IF) combination model, triple-frequency (TF) IF combination model, quad-frequency (QF) IF combination model, four five-frequency (FF) IF com-bination models and an FF uncombined (UC) model. The observation data of five stations for seven days are selected from the multi-GNSS experiment (MGEX) network, forming four time-frequency links ranging from 454.6 km to 5991.2 km. The positioning and time-frequency transfer performances of Galileo multi-frequency PPP are compared and evaluated using GBM (which denotes precise satellite orbit and clock bias products provided by Geo Forschung Zentrum (GFZ)), WUM (which denotes precise satellite orbit and clock bias products provided by Wuhan University (WHU)) and GRG (which denotes precise satellite orbit and clock bias products provided by the Centre National d’Etudes Spatiales (CNES)) precise products. The results show that the performances of the DF, TF, QF and FF PPP models are basically the same, the frequency stabilities of most links can reach sub10−16 level at 120,000 s, and the average three-dimensional (3D) root mean square (RMS) of position and average frequency stability (120,000 s) can reach 1.82 cm and 1.18 × 10−15, respectively. The differences of 3D RMS among all models are within 0.17 cm, and the differences in frequency stabilities (in 120,000 s) among all models are within 0.08 × 10−15. Using the GRG precise product, the solution performance is slightly better than that of the GBM or WUM precise product, the average 3D RMS values obtained using the WUM and GRG precise products are 1.85 cm and 1.77 cm, respectively, and the average frequency stabilities at 120,000 s can reach 1.13 × 10−15 and 1.06 × 10−15, respectively.

Effect of differentarterial occlusion pressure and intermittent mode on KAATSU-loaded deep-squat exercise on the characteristics of thigh muscle activation

Objective: To investigate the effect of different arterial occlusion pressure and intermittent time on KAATSU-loaded deep-squat exercise on the characteristics of thigh muscle activation, find out the suitable relative value of personal blood pressure limit causing the maximum activation, and to provide some theoretical basis and practical reference for athletes to carry on the KAATSU Training scientifically. Methods: Ten elite male players were recruited, four kinds of external pressure condition with 0% arterial occlusion pressure (AOP), 40%AOP, 50%AOP, 60%AOP, respectively, were performed with 30%1RM(One repetition maximum)intensity of intermittent and continuous KAASTU-loaded deep-squat exercise. Wave plus wireless surface electromyography instrument was used to collect the surface EMG signals of the lower thigh muscle group. Root mean square (RMS) calculation was used to estimate muscle activity level. The normalized RMS values of the anterior thigh group and posterior thigh group were calculated by RMS of MVC, two-factor ANOVA analysis of variance were used to explore the effect of the activation of various muscle on external express and intermittent mode, to analyze the discrepancy during different external pressure. Results: ①A two-factor analysis of variance showed that different %AOP had significant effect on the normalized values of RMS of muscle measured by KAATSU deep-squat exercise(P＜0.05), but intermittent mode had no significant effect on the standard value of RMS of muscle(P＞0.05). The interaction of external pressure and intermittent mode on muscle RMS was not significant(P＞0.05); ②The normalized RMS values of Rectus Femoris, Vastus Medialis, Vastus Lateralis, Biceps Femoris, Semitendinosus were significantly increased (P＜0.05)in 50% AOP pressure condition during intermittent and continuous exercise; ③ The normalized RMS values of RF and VL were significantly increased(P＜0.05)in 50% AOP pressure condition during intermittent and continuous exercise. The %MVC values of Vastus Medialis and Semitendinosus were significantly increased(P＜0.05)in 60% AOP pressure condition during intermittent exercise. Conclusion: This study further verified that 50% AOP pressure can significantly improve the optimal activation quadriceps and posterior thigh groups and produce the best training effect for the high level handball players. It can not only promote the coordinated development of the agonist and antagonist, but also avoid overloading and prevent hamstring injury. At the same time, the intermittent mode is recommended to adopt the decompression intermittent mode.

The Neuromuscular Characteristics of Gymnasts' Jumps and Landings at Particular Stages of Sports Training.

Safe and proper landings are crucial elements of gymnastics events. Long-term training leads to specific neuromuscular adaptations which are yet to be explored in terms of gymnastic landings. The aim of the study was to assess differences in landings’ neuromuscular characteristics between gymnasts at three subsequent gymnastic training stages and age-matched non-athletes. Forty-six gymnasts (G) and 58 controls (C) performed countermovement jumps on a force plate with simultaneous surface electromyography (SEMG) of lower body muscles, measured during the pre-(100 ms) and post-landing phase (0-100 and 0-200 ms). Three age groups participated in the study: 8–10 (G1, C1), 12–14 (G2, C2), 18–25 (G3, C3) years. Analysis included the normalized root mean square (NRMS) SEMG signal and ground reaction forces (GRFs). Gymnasts achieved 13% higher values (p = 0.04) of relative peak GRFs in comparison with controls. It was especially seen in 8–10-year-olds: G1 presented 33% higher (p = 0.03) results than C1 and G2. In SEMG analysis, gymnasts showed overall lower NRMS values in comparison with the controls. In the pre-landing phase, the NRMS in the rectus femoris was from 1.6 up to 3.4 times higher for C1 (p = 0.02) than for C2, G2, C3, and G3. Gymnasts across subsequent training stages exhibit different patterns of neuromuscular coordination during landings. The highest GRF observed in the youngest gymnasts may be a potential risk factor of injuries. Therefore, further injury-focused investigation is recommended to monitor landing strategies among gymnasts of different stages with particular emphasis on the beginners.

Increased Muscle Activity Accompanying With Decreased Complexity as Spasticity Appears: High-Density EMG-Based Case Studies on Stroke Patients.

Spasticity is a major contributor to pain, disabilities and many secondary complications after stroke. Investigating the effect of spasticity on neuromuscular function in stroke patients may facilitate the development of its clinical treatment, while the underlying mechanism of spasticity still remains unclear. The aim of this study is to explore the difference in the neuromuscular response to passive stretch between healthy subjects and stroke patients with spasticity. Five healthy subjects and three stroke patients with spastic elbow flexor were recruited to complete the passive stretch at four angular velocities (10°/s, 60°/s, 120°/s, and 180°/s) performed by an isokinetic dynamometer. Meanwhile, the 64-channel electromyography (EMG) signals from biceps brachii muscle were recorded. The root mean square (RMS) and fuzzy entropy (FuzzyEn) of EMG recordings of each channel were calculated, and the relationship between the average value of RMS and FuzzyEn over 64-channel was examined. The two groups showed similar performance from results that RMS increased and FuzzyEn decreased with the increment of stretch velocity, and the RMS was negatively correlated with FuzzyEn. The difference is that stroke patients showed higher RMS and lower FuzzyEn during quick stretch than the healthy group. Furthermore, compared with the healthy group, distinct variations of spatial distribution within the spastic muscle were found in the EMG activity of stroke patients. These results suggested that a large number of motor units were recruited synchronously in the presence of spasticity, and this recruitment pattern was non-uniform in the whole muscle. Using a combination of RMS and FuzzyEn calculated from high-density EMG (HD-EMG) recordings can provide an innovative insight into the physiological mechanism underlying spasticity, and FuzzyEn could potentially be used as a new indicator for spasticity, which would be beneficial to clinical intervention and further research on spasticity.

Application of a neural interface for restoration of leg movements: Intra-spinal stimulation using the brain electrical activity in spinally injured rabbits.

This study aimed to design a neural interface that extracts movement commands from the brain to generate appropriate intra-spinal stimulation to restore leg movement. This study comprised four steps: (1) Recording electrocorticographic (ECoG) signals and corresponding leg movements in different trials. (2) Partial laminectomy to induce spinal cord injury (SCI) and detect motor modules in the spinal cord. (3) Delivering appropriate intra-spinal stimulation to the motor modules for restoration of the movements to those documented before SCI. (4) Development of a neural interface created by sparse linear regression (SLiR) model to detect movement commands transmitted from the brain to the modules. Correlation coefficient (CC) and normalized root mean square (NRMS) error was calculated to evaluate the neural interface effectiveness. It was found that by stimulating detected spinal cord modules, joint angle evaluated before SCI was not significantly different from that of post-SCI (P > 0.05). Based on results of SLiR model, overall CC and NRMS values were 0.63 ± 0.14 and 0.34 ± 0.16 (mean ± SD), respectively. These results indicated that ECoG data contained information about intra-spinal stimulations and the developed neural interface could produce intra-spinal stimulation based on ECoG data, for restoration of leg movements after SCI.

Hourly PWV Dataset Derived from GNSS Observations in China.

The rapid variation of atmospheric water vapor is important for a regional hydrologic cycle and climate change. However, it is rarely investigated in China, due to the lack of a precipitable water vapor (PWV) dataset with high temporal resolution. Therefore, this study focuses on the generation of an hourly PWV dataset using Global Navigation Satellite System (GNSS) observations derived from the Crustal Movement Observation Network of China. The zenith total delay parameters estimated by GAMIT/GLOBK software are used and validated with an average root mean square (RMS) error of 4–5 mm. The pressure (P) and temperature (T) parameters used to calculate the zenith hydrostatic delay (ZHD) and weighted average temperature of atmospheric water vapor (Tm) are derived from the fifth-generation reanalysis dataset of the European Centre for Medium-Range Weather Forecasting (ECMWF ERA5) products. The values of P and T at the GNSS stations are obtained by interpolation in the horizontal and vertical directions using empirical formulas. Tm is calculated at the GNSS stations using the improved global pressure and temperature 2 wet (IGPT2w) model in China with an RMS of 3.32 K. The interpolated P and T are validated by interpolating the grid-based ERA5 data into radiosonde stations. The average RMS and bias of P and T in China are 2.71/−1.11 hPa and 1.88/−0.51 K, respectively. Therefore, the error in PWV with a theoretical RMS of 1.85 mm over the period of 2011–2017 in China can be obtained. Finally, the hourly PWV dataset in China is generated and the practical accuracy of the generated PWV dataset is validated using the corresponding AERONET and radiosonde data at specific stations. Numerical results reveal that the average RMS values of the PWV dataset in the four geographical regions of China are less than 3 mm. A case analysis of the PWV diurnal variations as a response to the EI Niño event of 2015–2016 is performed. Results indicate the capability of the hourly PWV dataset of monitoring the rapid water vapor changes in China.

GPS satellite inter-frequency clock bias estimation using triple-frequency raw observations

This study proposes a unified uncombined model to estimate GPS satellite inter-frequency clock bias (IFCB) in both triple-frequency code and carrier-phase observations. In the proposed model, the formulae of both phase-based and code-based IFCBs are rigorously derived. Specifically, satellite phase-based IFCB refers to its time-variant part and it is modeled as a periodic function related to the sun–spacecraft–earth angle. A zero-mean condition of all available GPS satellites that support triple-frequency data is introduced to render satellite code-based IFCB estimable. Three months of data from 40 globally distributed stations of the International GNSS Service Multi-GNSS Experiment are used to test our method. The results show that the four-order periodic function is suitable for eliminating the 12-h, 6-h, 4-h, and 3-h periods that exist in the a posteriori phase residuals when no periodic function is used. For comparison, the geometry-free and ionosphere-free (GFIF) phase combination and differential code bias (DCB) products released by DLR (German Aerospace Center) and IGG (Institute of Geodesy and Geophysics, China) are also used to calculate the satellite phase-based and code-based IFCBs, respectively. The results show that (1) the average root mean square (RMS) of the phase-based IFCB difference between the proposed method and the GFIF phase combination is 4.3 mm; (2) the average RMS in the eclipse period increased by 50% compared with the average RMS in the eclipse-free period; (3) the mean monthly STD for code-based IFCB from the proposed method is 0.09 ns; and (4) the average RMS values of code-based IFCB differences between the proposed method and the DCB products released by DLR and IGG are 0.32 and 0.38 ns. This proposed model also provides a general approach for multi-frequency GNSS applications such as precise orbit and clock determination.

Data-driven synthetic MRI FLAIR artifact correction via deep neural network.

FLAIR (fluid attenuated inversion recovery) imaging via synthetic MRI methods leads to artifacts in the brain, which can cause diagnostic limitations. The main sources of the artifacts are attributed to the partial volume effect and flow, which are difficult to correct by analytical modeling. In this study, a deep learning (DL)-based synthetic FLAIR method was developed, which does not require analytical modeling of the signal. To correct artifacts in synthetic FLAIR using a DL method. Retrospective. A total of 80 subjects with clinical indications (60.6 ± 16.7 years, 38 males, 42 females) were divided into three groups: a training set (56 subjects, 62.1 ± 14.8 years, 25 males, 31 females), a validation set (1 subject, 62 years, male), and the testing set (23 subjects, 57.3 ± 20.4 years, 13 males, 10 females). 3 T MRI using a multiple-dynamic multiple-echo acquisition (MDME) sequence for synthetic MRI and a conventional FLAIR sequence. Normalized root mean square (NRMSE) and structural similarity (SSIM) were computed for uncorrected synthetic FLAIR and DL-corrected FLAIR. In addition, three neuroradiologists scored the three FLAIR datasets blindly, evaluating image quality and artifacts for sulci/periventricular and intraventricular/cistern space regions. Pairwise Student's t-tests and a Wilcoxon test were performed. For quantitative assessment, NRMSE improved from 4.2% to 2.9% (P < 0.0001) and SSIM improved from 0.85 to 0.93 (P < 0.0001). Additionally, NRMSE values significantly improved from 1.58% to 1.26% (P < 0.001), 3.1% to 1.5% (P < 0.0001), and 2.7% to 1.4% (P < 0.0001) in white matter, gray matter, and cerebral spinal fluid (CSF) regions, respectively, when using DL-corrected FLAIR. For qualitative assessment, DL correction achieved improved overall quality, fewer artifacts in sulci and periventricular regions, and in intraventricular and cistern space regions. The DL approach provides a promising method to correct artifacts in synthetic FLAIR. 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1413-1423.

Are there sex differences in muscle coordination of the upper girdle during a sustained motor task?

PurposeThe higher prevalence of work-related musculoskeletal disorders among women compared with men could be explained by sex-gender differences related to biological and physiological processes. The aim of this study was to evaluate sex differences in motor coordination during a sustained and repetitive motor task. MethodsSeventeen healthy females and 21 healthy males participated. The surface electromyography (sEMG) of the trapezius portions and serratus anterior were recorded. Root mean square (RMS) values were computed to assess the level of muscle activity. The standard deviation (SD) and coefficient of variation (CV) were computed as metrics of size of variability. The normalized mutual information (NMI) values were calculated as index of functional connectivity between muscles pairs. ResultsFemales had higher normalized RMS values for the upper trapezius (acromial fibers) and serratus anterior muscles compared with males. RMS decreased, SD and CV increased while NMI decreased for almost all muscle pairs over time. ConclusionThe present work showed some signs of sex differences in muscle coordination of the shoulder girdle during a sustained motor task, performed with the upper limb positioned below of the shoulder level.

Mirror therapy can promote the activation and synchronization of lower-limb muscles after stroke

Objective To explore the effects of mirror therapy on the lower-limb muscles of hemiplegic stroke survivors. Methods Sixty-two hemiplegic stroke survivors were divided by stratified random grouping into a mirror group and a control group, each of 31. Both groups accepted routine rehabilitation training, while the mirror group was additionally provided with mirror therapy to train the non-paretic limb for 30 min per day, 5 days a week, lasting 4 weeks. Before and after the 4 weeks of training, integrated electromyography was performed and the maximum voluntary contraction force (MVC) of the tibialis anterior, rectus femoris and biceps femoris of the paretic limb were recorded and compared. Results Compared with before the training, the average root mean square values of the electromyographs and the average MVCs of all three muscles had improved significantly in both groups after training. Compared with the control group, the improvements were significantly greater in the mirror group. Conclusion Mirror therapy can promote the activation and synchronization of motor units, as well as increase the number discharging and the total discharge, promoting the recovery of muscle strength. Key words: Surface electromyography; Mirror therapy; Stroke; Hemiplegia; Lower limbs