Search Results (38)

Background/Objectives: High-precision measurement tools are needed to measure relevant changes in strength and power in children with neuromuscular diseases. The aim of this study was to determine the feasibility (i), reproducibility (ii), and validity (iii) of isokinetic dynamometry in this population. Methods: Isometric and isokinetic knee and elbow flexion and extension were measured twice on the same day. Feasibility was based on completion rate and acceptability. Acceptability was measured with a 100 mm visual analog scale. We measured reproducibility as the intraclass correlation coefficient (ICC-agreement), standard error of measurement (SEM), and smallest detectable change (SDC). We investigated relationships between isometric strength and isokinetic power with Pearson’s correlation coefficient. ROC curves were used to determine the cutoff of isometric strength to conduct isokinetic measurements. Results: Fifty children with NMDs participated with completion rates of 78–90% for isometric and 39–75% for isokinetic measurements. Acceptability was high (mean (SD) = 73 (19) mm). The ICCs for all measurements were over 0.9 (95% confidence interval (CI) = 0.932–0.998). The SEM% ranged from 5 to 14% and the SDC% from 14 to 28%. The correlations of strength and power were high (Pearson’s correlation coefficient >0.9 (95% CI: 0.89–0.98)). The isometric strength needed to conduct isokinetic measurements ranged from 11.1 N in elbow flexors to 24.9 N in knee extensors. Conclusions: Isokinetic dynamometry is a feasible and reproducible method for measuring isometric strength in children with neuromuscular diseases with moderate weakness to normal strength, and isokinetic measurements are only feasible in knee extension for children with moderate weakness to normal strength. The convergent validity between isometric strength and power at low velocities is high. Full article

Blind tees, as important junctions, are widely used in offshore oil and gas transportation systems to improve mixing flow conditions and measurement accuracies in curved pipes. Despite the significance of blind tees, their unsteady flow characteristics and mixing mechanisms in turbulent flow regimes are not clearly established. Therefore, in this study, Unsteady Reynolds-Averaged Navier–Stokes (URANS) simulations, coupled with Explicit Algebraic Reynolds Stress Model (EARSM), are employed to explore the complex turbulent flow characteristics within blind-tee pipes. Firstly, the statistical flow features are investigated based on the time-averaged results, and the swirl dissipation analysis reveals an intense dissipative process occurring within blind tees, surpassing conventional elbows in swirling intensity. Then, the instantaneous flow characteristics are investigated through time and frequency domain analysis, uncovering the oscillatory patterns and elucidating the mechanisms behind unsteady secondary flow motions. In a 2D-length blind tee, a nondimensional dominant frequency of oscillation (St_bt = 0.0361) is identified, highlighting the significant correlation between dominant frequencies inside and downstream of the plugged section, which emphasizes the critical role of the plugged structure in these unsteady motions. Finally, a power spectra analysis is conducted to explore the influence of blind-tee structures, indicating that the blind-tee length of l_bt = 2D enhances the flow-mixing conditions by amplifying the oscillation intensities of secondary flow motions. Full article

The present study aimed to explore the clinical applicability of ultrasound super-resolution imaging (US SRI) for assessing renal microcirculation in patients with acute kidney injury (AKI). A total of 62 patients with sepsis were enrolled in the present study—38 with AKI and 24 control patients—from whom renal ultrasounds and clinical data were obtained. SonoVue contrast (1.5 mL) was administered through the elbow vein and contrast-enhanced ultrasound (CEUS) images were obtained on a Mindray Resona A20 ultrasound unit for 2 min. The renal perfusion time-intensity curve (TIC) was analyzed and, after 15 min, additional images were obtained to create a microscopic blood flow map. Microvascular density (MVD) was calculated and its correlation with serum creatinine (Scr) levels was analyzed. There were significant differences in heart rate, Scr, blood urea nitrogen, urine volume at 24 h, and glomerular filtration rate between the two groups (p < 0.01), whereas other characteristics, such as renal morphology, did not differ significantly between the AKI group and control group (p > 0.05). The time to peak and mean transit times of the renal cortex in the AKI group were prolonged compared to those in the control group (p < 0.01), while the peak intensity and area under the TIC were lower than those in the control group (p < 0.05). The MVD of the renal cortex in the AKI group was lower than that in the control group (18.46 ± 5.90% vs. 44.93 ± 11.65%; p < 0.01) and the MVD in the AKI group showed a negative correlation with Scr (R = −0.84; p < 0.01). Based on the aforementioned results, US SRI can effectively assess renal microcirculation in patients with AKI and is a noninvasive technique for the diagnosis of AKI and quantitative evaluation of renal microcirculation. Full article

Background and Objectives: Long-term outcomes of immediately postoperative rotational malreduction in the axial plane after operative treatment of supracondylar humeral fractures (SCHF) are unknown. This study aimed to investigate the long-term clinical outcomes and associated factors for immediately postoperative rotational malreduction of SCHF. Materials and methods: In this retrospective case–control study, 88 patients who underwent surgery for Gratland type III SCHF were enrolled between January 2012 and January 2020. Among them, 49 patients had immediately postoperative malrotational reduction (rotational malreduction group) and 39 patients had no rotational deformity (control group). To evaluate the associated factors for immediately postoperative rotational malreduction, demographic data, fracture patterns, physical examination signs, and preoperative radiological parameters were analyzed. To compare the clinical outcomes, operation time, range of motion of the elbow, time from operation to full range of motion, and Flynn criteria were evaluated. The Oxford elbow score was used to investigate long-term clinical outcomes for patients five years after operation. Results: The mean age was 5.7 ± 2.3 years and mean follow-up period was 15.7 ± 4.0 months. The rotational malreduction group had significantly more patients with oblique fracture pattern (p = 0.031) and Pucker sign (p = 0.016) and showed a significantly longer operative time (p = 0.029) than the control group. Although there was no significant difference in the range of elbow motion and the Flynn criteria, the Kaplan–Meier survival curve showed a longer time to recover the full range of elbow motion in the rotational malreduction group (p = 0.040). There were no significant differences in the long-term clinical outcomes assessed using the Oxford elbow score (p = 0.684). Conclusions: Oblique fracture pattern and Pucker sign may be associated with immediately postoperative rotational malreduction in the axial plane. Although patients with immediately postoperative rotational malreduction showed favorable results of long-term clinical outcomes, they required more weeks to recover the full range of elbow motion. Full article

Background and Objectives: Considering the fact that prematurity echoes in terms of motor development even up to the age of adolescence, through the presence of deficiencies, the importance of starting kinetotherapeutic treatment as soon as possible is highlighted, even in the absence of brain damage or obvious motor delays. Therefore, the objectives of this study are to analyze the factors that influence the level of motor development of premature babies up to 9 months and identify the motor development curve of premature babies according to the three stages of motor development: the position of symmetrical support on the elbows at 3 months, sitting with support at 6 months, and verticalization at 9 months. Materials and Methods: This prospective pilot study was conducted within a rehabilitation facility located in Targu Mureș, Romania, spanning a duration of 2 years from June 2021 to 2023. Results: The study involved a population of 78 children, all premature infants, selected from the patient pool of the rehabilitation facility, specifically chosen based on adherence to the predetermined inclusion and exclusion criteria outlined in the study protocol. Two physiotherapists specialized in child recovery were involved in the study, and one performed the assessments and the other applied the Bobath therapy. Conclusions: Early physiotherapy interventions can have a positive influence in terms of reducing differences in motor development between preterm and full-term infants. This study identified several factors that influence the motor development of premature infants. Among these, the most prominent biological factors were gestational age and birth weight. Full article

To assess changes in treatment modalities for supracondylar humerus fractures (SCHFs) at a large pediatric university hospital, we analyzed patient data from 2014 to 2022. A total of 233 SCHFs treated surgically at our hospital were included. To evaluate postoperative outcome and quality of life, DASH and EuroQol-5D-Y questionnaires were sent to patients. In addition to a significant fluctuation in fracture severity, we found an increase in training interventions (more surgeries were performed by trainees) and a significant decrease in surgery times after 2016. From 2020, there was a significant shift in the type of surgical method away from closed reduction with elastic stable intramedullary nailing (ESIN) and towards closed reduction and crossed K-wire osteosynthesis (CRK). Surgeries performed in the morning and evening hours increased, while those performed in the afternoon and after midnight decreased. After a mean follow-up of 4 years, there was no difference in elbow function between ESIN and open reduction and K-wires (ORK). Treatment with ESIN was equivalent to ORK in terms of function, at least in the medium-term follow-up. In summary, the combination of shifting treatment from SCHF to daytime hours, increasing trainee participation and using cross K-wire fixation instead of ESIN had no negative impact on surgery times. In our setting, these measures have reduced resource utilization and increased efficiency without compromising patient care. Full article

A vertical pipeline pump is a type of single-stage, single-suction centrifugal pump with a curved elbow input. The inhomogeneous flow of the impeller inlet coexists with the unique elbow inlet channel, making it simple to generate the inlet vortical secondary flow. This paper aimed to optimize elbow inlet channel performance using a backpropagation (BP) neural network enhanced by the Sand Cat Swarm algorithm. The elbow flow channel’s midline and cross section shapes were fitted with a spline curve, and the parametric model of the curve was then constructed. Nine initial variables were filtered down to four optimization variables using the partial factor two-level (P2) and Plackett-Burman (P-B) experimental designs and multivariate analysis of variance. The sample space was generated by 50 groups of experiment samples, and the Sand Cat Swarm algorithm to optimize the BP (SCSO-BP) neural network and the approximation model of four variables were built. A genetic algorithm (GA) was applied to determine the optimal parameters among the approximate models in the sample space, and the ideal parameter combination of the elbow inlet channel was achieved. The findings demonstrated a strong agreement between the experimental and numerical simulation results. With reduced error fluctuation in inaccuracy and a more consistent fluctuation range, the approximate prediction model based on the optimized Sand Cat Swarm algorithm performed better. The optimized inlet model minimized the impact loss on the inlet wall, improved the velocity distribution uniformity of the inlet impeller, increased the pump efficiency by about 5% and the head by about 7.48% near the design flow, and broadened the efficient region of the pump. Full article

Utilizing “You only look once” (YOLO) v4 AI offers valuable support in fracture detection and diagnostic decision-making. The purpose of this study was to help doctors to detect and diagnose fractures more accurately and intuitively, with fewer errors. The data accepted into the backbone are diversified through CSPDarkNet-53. Feature maps are extracted using Spatial Pyramid Pooling and a Path Aggregation Network in the neck part. The head part aggregates and generates the final output. All bounding boxes by the YOLO v4 are mapped onto the 3D reconstructed bone images after being resized to match the same region as shown in the 2D CT images. The YOLO v4-based AI model was evaluated through precision–recall (PR) curves and the intersection over union (IoU). Our proposed system facilitated an intuitive display of the fractured area through a distinctive red mask overlaid on the 3D reconstructed bone images. The high average precision values (>0.60) were reported as 0.71 and 0.81 from the PR curves of the tibia and elbow, respectively. The IoU values were calculated as 0.6327 (tibia) and 0.6638 (elbow). When utilized by orthopedic surgeons in real clinical scenarios, this AI-powered 3D diagnosis support system could enable a quick and accurate trauma diagnosis. Full article

With the rapid increase in new energy penetration, the uncertainty of the power system increases sharply. We can smooth out fluctuations and promote the more grid-friendly integration of new energy by combining it with energy storage. This paper proposes an evaluation method for assessing the value of a combined power plant system of new energy and energy storage using robust scheduling rules. Firstly, the k-means clustering algorithm is improved by using the elbow method in order to generate typical scenarios that can be used for the operation optimization of the combined power plant system of new energy and energy storage. Then, a two-stage robust optimization model of the combined power plant system of new energy and energy storage with a min–max–min structure is constructed according to the uncertainty of new energy. In this model, the operation constraints and coordinated control of wind–solar–thermal–storage units are considered. By constructing the uncertainty set of the new energy output, the overall operating cost of the system is minimized and uncertainty adjustment parameters are introduced to flexibly adjust the conservatism of the scheduling rules. Furthermore, based on the column and constraint generation algorithm and strong duality theory, the original problem can be decomposed into a master problem and subproblems with mixed integer linear characteristics for an alternating solution, so as to obtain the optimal solution of the original problem, and finally obtain the robust scheduling rule with the lowest operating cost under the worst scenario. Finally, based on the wind and solar power output curves and the output of each unit under the robust scheduling rules, combined with the value estimation method of the combined power plant system of new energy and energy storage, the value of the combined power plant system of new energy and energy storage is evaluated. Through the establishment of models and example analysis, it is proven that raising the quantity of the grid-connected power generated with new energy will cause an increase in the volatility of the power system; it will also bring considerable benefits to new energy plants, and the energy storage can improve the stability of the system. The above can provide references for the subsequent energy storage configuration in the planning of a combined power plant system of new energy and energy storage. Full article

This paper presents the mechanical design and test of a portable hand-elbow combination linkage upper limb rehabilitation robot, which can realize the joint movement of the hand joint and elbow joint and reproduce the complete grasping action. The joints that need bionic support are determined according to the characteristics of human upper limbs and hands, and the overall bionic mechanism is designed. The Motion module in SolidWorks is used to simulate and analyze the rehabilitation robot. The measurement experiment and grasping experiment of joint mobility are carried out on the experimental prototype. As a result, the angular displacement and linear displacement curves obtained via the simulation results are smooth. The measurement experiment of the joint range of motion confirms that the joint range of motion is also within the range of the normal joint angle of the human body, and the grasping experiment shows that the exoskeleton can grasp and lift a 1.801-kg cylindrical object and other daily necessities of different shapes. This result shows that the design of the portable hand-elbow combination linkage upper limb rehabilitation robot is reasonable, can satisfy the rehabilitation training requirements of the hand and upper limb, and has some ability to assist users in daily life. Full article

Photovoltaics have uncertain characteristics. If a high proportion of photovoltaics are connected to the distribution network, the voltage will exceed the limit. In order to solve this problem, a voltage regulation method of a distribution network considering energy storage partition configuration is proposed. Taking the minimum total voltage deviation, the minimum total cost, the minimum total power loss, and the minimum energy storage device installation ratio as the objective function, and considering various conditions, such as voltage deviation constraint and energy storage constraint, a mathematical model of voltage regulation is established. Firstly, a high proportion of photovoltaics are connected to the distribution network, and the voltage deviation curve is obtained. The optimal k value is determined by the elbow rule. The voltage deviation curve of each node is clustered by the k-means algorithm so as to determine the energy storage device partition. The energy storage device is connected to various clustering centers, and then the weighting factor of each objective function is determined by the fuzzy comprehensive evaluation method. For comparison and analysis, (k + 1) schemes are determined through the partition configuration of (k + 1) energy storage devices. Then, the model is solved by particle swarm optimization, and the unit output result and the minimum objective function value are obtained. Finally, an example of IEEE33 is used to verify the effectiveness of the proposed model. Full article

Rock particles in excavated materials can damage and wear down slurry discharge pipelines when slurry shield tunneling occurs in a pebble layer and rock ground. This pipeline damage and wear, if not properly dealt with, can lead to a broken-down tunneling machine. Based on a slurry shield tunneling project in China, damage and wear were thoroughly examined. The observed pipeline wear and leaks, transported rock particles, mechanical properties, and flow rate of the carrier slurry were presented. The measured results showed that the wear rates of a straight pipe, a pipe along a curved tunnel, a 60° inclined pipe, and a 90° elbow pipe in pebble ground were approximately 0.71 mm/100 rings, 1 mm/100 rings, 2.14 mm/100 rings, and 4 mm/100 rings, respectively. When the machine drove into rock ground, the wear rates increased by one to two times, which could be attributed to the sharper particle shapes. Countermeasures to address these issues, such as adjusting the pipeline layout, welding reinforcement plates in advance, and preparing additional pipes, were highlighted. The wear rates of different types of pipes, the effectiveness of new pipeline fixing methods, and the probability of pipeline leaks in different strata were discussed in detail. Full article

Background and Objectives: Studies have suggested that, by applying certain nerve ultrasound scores, demyelinating and axonal polyneuropathies can be differentiated. In the current study, we investigated the utility of ultrasound pattern sub-score A (UPSA) and intra- and internerve cross-sectional area (CSA) variability in the diagnostic evaluation of demyelinating neuropathies. Materials and Methods: Nerve ultrasound was performed in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and acute inflammatory demyelinating polyneuropathy (AIDP) and compared to patients with axonal neuropathies. The UPSA, i.e., the sum of ultrasound scores at eight predefined measurement points in the median (forearm, elbow and mid-arm), ulnar (forearm and mid-arm), tibial (popliteal fossa and ankle) and fibular (lateral popliteal fossa) nerves, was applied. Intra- and internerve CSA variability were defined as maximal CSA/minimal CSA for each nerve and each subject, respectively. Results: A total of 34 CIDP, 15 AIDP and 16 axonal neuropathies (including eight axonal Guillain-Barré syndrome (GBS), four hereditary transthyretin amyloidosis, three diabetic polyneuropathy and one vasculitic neuropathy) were included. A total of 30 age- and sex-matched healthy controls were recruited for comparison. Significantly enlarged nerve CSA was observed in CIDP and AIDP with significantly higher UPSA in CIDP compared to the other groups (9.9 ± 2.9 vs. 5.9 ± 2.0 vs. 4.6 ± 1.9 in AIDP vs. axonal neuropathies, p < 0.001). A total of 89.3% of the patients with CIDP had an UPSA score ≥7 compared to the patients with AIDP (33.3%) and axonal neuropathies (25.0%) (p < 0.001). Using this cut-off, the performance of UPSA in differentiating CIDP from other neuropathies including AIDP was excellent (area under the curve of 0.943) with high sensitivity (89.3%), specificity (85.2%) and positive predictive value (73.5%). There were no significant differences in intra- and internerve CSA variability between the three groups. Conclusion: The UPSA ultrasound score was useful in distinguishing CIDP from other neuropathies compared to nerve CSA alone. Full article

The large-scale grid connection of new energy will affect the optimization of power flow. In order to solve this problem, this paper proposes a power flow optimization strategy model of a distribution network with non-fixed weighting factors of source, load and storage. The objective function is the lowest cost, the smallest voltage deviation and the smallest power loss, and many constraints, such as power flow constraint, climbing constraint and energy storage operation constraint, are also considered. Firstly, the equivalent load curve is obtained by superimposing the output of wind and solar turbines with the initial load, and the best k value is obtained by the elbow rule. The k-means algorithm is used to cluster the equivalent load curve in different periods, and then the fuzzy comprehensive evaluation method is used to determine the weighting factor of the optimization model in each period. Then, the particle swarm optimization algorithm is used to solve the multi-objective power flow optimization model, and the optimal strategy and objective function values of each unit output in the operation period are obtained. Finally, IEEE33 is used as an example to verify the effectiveness of the proposed model through two cases: a fixed proportion method to determine the weighting factor, and this method to determine the weighting factor. The proposed method can improve the economy and reliability of distribution networks. Full article

The problem of distribution network operation optimization is diversified and uncertain. In order to solve this problem, this paper proposes a method of distribution network operation optimization considering wind-solar clustering, which includes source load and storage. Taking the total operating cost as the objective function, it includes network loss cost, unit operating cost, and considers a variety of constraints such as energy storage device constraints and demand response constraints. This paper aims to optimize the operation according to different wind-solar clustering scenes to improve the economy of distribution network. Taking the 365-day wind-solar output curves as the research object, K-means clustering is carried out, and the best k value is obtained by elbow rule. The second-order cone programming method and solver are used to solve the optimization model of each typical scenario, and the operation optimization analysis of each typical scenario obtained by clustering is carried out. Taking IEEE33 system and local 365-day wind-solar units output scenes as examples, the period is 24 h, which verifies the effectiveness of the proposed method. The proposed method has guiding significance for the operation optimization of distribution network. Full article