On the use of thermal forces to probe kinesin's response to force.

The stepping dynamics of cytoskeletal motor proteins determines the dynamics of cargo transport. In its native cellular environment, a molecular motor is subject to forces from several sources including thermal forces and forces ensuing from the interaction with other motors bound to the same cargo. Understanding how the individual motors respond to these forces can allow us to predict how they move their cargo when part of a team. Here, using simulation, we show that details of how the kinesin motor responds to small assisting forces-which, at the moment, are not experimentally constrained-can lead to significant changes in cargo dynamics. Using different models of the force-dependent detachment probability of the kinesin motor leads to different predictions on the run-length of the cargo they carry. These differences emerge from the thermal forces acting on the cargo and transmitted to the motor through the motor tail that tethers the motor head to the microtubule. We show that these differences appear for cargo carried by individual motors or motor teams, and use our findings to propose the use of thermal forces as a probe of kinesin's response to force in this otherwise inaccessible force regime.

Deep learning-based diagnosis of stifle joint diseases in dogs.

In this retrospective, analytical study, we developed a deep learning-based diagnostic model that can be applied to canine stifle joint diseases and compared its accuracy with that achieved by veterinarians to verify its potential as a reliable diagnostic method. A total of 2382 radiographs of the canine stifle joint from cooperative animal hospitals were included in a dataset. Stifle joint regions were extracted from the original images using the faster region-based convolutional neural network (R-CNN) model, and the object detection accuracy was evaluated. Four radiographic findings: patellar deviation, drawer sign, osteophyte formation, and joint effusion, were observed in the stifle joint and used to train a residual network (ResNet) classification model. Implant and growth plate groups were analyzed to compare the classification accuracy against the total dataset. All deep learning-based classification models achieved target accuracies exceeding 80%, which is comparable to or slightly less than those achieved by veterinarians. However, in the case of drawer signs, further research is necessary to improve the low sensitivity of the model. When the implant group was excluded, the classification accuracy significantly improved, indicating that the implant acted as a distraction. These results indicate that deep learning-based diagnoses can be expected to become useful diagnostic models in veterinary medicine.

On Weather Data-Based Prediction of Gamma Exposure Rates Using Gradient Boosting Learning for Environmental Radiation Monitoring.

Gamma radiation has been classified by the International Agency for Research on Cancer (IARC) as a carcinogenic agent with sufficient evidence in humans. Previous studies show that some weather data are cross-correlated with gamma exposure rates; hence, we hypothesize that the gamma exposure rate could be predicted with certain weather data. In this study, we collected various weather and radiation data from an automatic weather system (AWS) and environmental radiation monitoring system (ERMS) during a specific period and trained and tested two time-series learning algorithms-namely, long short-term memory (LSTM) and light gradient boosting machine (LightGBM)-with two preprocessing methods, namely, standardization and normalization. The experimental results illustrate that standardization is superior to normalization for data preprocessing with smaller deviations, and LightGBM outperforms LSTM in terms of prediction accuracy and running time. The prediction capability of LightGBM makes it possible to determine whether the increase in the gamma exposure rate is caused by a change in the weather or an actual gamma ray for environmental radiation monitoring.

Characteristics of Plasma Flow for Microwave Plasma Assisted Aerosol Deposition.

To validate the possibility of the developed microwave plasma source with a novel structure for plasma aerosol deposition, the characteristics of the plasma flow velocity generated from the microwave plasma source were investigated by a Mach probe with pressure variation. Simulation with the turbulent model was introduced to deduce calibration factor of the Mach probe and to compare experimental measurements for analyses of collisional plasma conditions. The results show calibration factor does not seem to be a constant parameter and highly dependent on the collision parameter. The measured plasma flow velocity, which witnessed fluctuations produced by a shock flow, was between 400 and 700 m/s. The optimized conditions for microwave plasma assisted aerosol deposition were derived by the results obtained from analyses of the parameters of microwave plasma jet. Under the optimized conditions, Y2O3 coatings deposited on an aluminum substrate were investigated using scanning electron microscope. The results presented in this study show the microwave plasma assisted aerosol deposition with the developed microwave plasma source is highly feasible for thick films with >50 µm.

Associations between matrilin-1 gene polymorphisms and adolescent idiopathic scoliosis curve patterns in a Korean population.

Adolescent idiopathic scoliosis (AIS) is a complex disorder with an unclear etiology and pathogenesis. In previous studies, genome-wide linkage and genetic association analyses have been carried out to find genetic factors linked with AIS. In this study, we examined whether the susceptibility to AIS is associated with MATN1 gene polymorphisms in a Korean population, which included 166 individuals with AIS and 126 controls. We found that there were no statistically significant associations between any of the MATN1-linked allele or genotype frequencies between AIS and controls. However, statistically significant associations were found at single nucleotide polymorphism (SNP) rs1065755 when comparing the curve patterns of AIS with the controls. The A allele of SNP rs1065755 was associated with a higher risk of AIS than the allele G in the genotype-phenotype (curve pattern) analysis (P = 0.029). In addition, the frequency of the A allele of SNP rs1065755 in AIS with double major curves was higher than in controls (P = 0.021, ORs = 2.56 within 95% CI = 1.12-5.83). Additionally, among the predicted common haplotypes, the frequency of the haplotype GATT (31.3%) in AIS with double major curves was higher than in controls (15.2%) (P = 0.024, ORs = 2.54 within 95% CI = 1.11-5.84). We conclude that the A allele of SNP rs1065755 in the MATN1 gene is associated with AIS.

Activity of all JNK isoforms contributes to neurite growth in spiral ganglion neurons.

Jun N-terminal kinase (JNK) is a multifunctional protein kinase crucial for neuronal apoptosis as well as neurite growth. We have previously shown that JNK activity is correlated with spiral ganglion neuron (SGN) apoptosis following hair cell loss in rats (Alam et al., 2007) implying that JNK inhibition may have therapeutic potential to protect SGNs in deaf individuals. Here we investigated the role of JNK in neurite outgrowth from cultured neonatal rat and mouse SGNs. We show that JNK is required for initial growth of neurites and for continued extension of already established neurites. The effect of JNK inhibition on neurite growth is rapid and is also rapidly reversible after washout of the inhibitor. Using phosphoJNK immunoreactivity as an indicator, we show that JNK is activated in growth cones within 30 min after transfer to medium lacking neurotrophic stimuli (5 K medium) but activation in the nucleus and soma requires hours. By transfecting epitope-tagged JNK1, JNK2, or JNK3 isoforms into SGNs, we found that all are present in the nucleus and cytoplasm and that there is no preferential redistribution to the nucleus after transfer to 5 K medium. Cotransfection of dominant-negative (dn) JNK1 and JNK2 into SGNs reduced neurite growth, although transfection of dnJNK1 or dnJNK2 alone had no significant effect. SGNs cultured from JNK3(-/-) mice showed reduced neurite growth that was further reduced by transfection of dnJNK1 and dnJNK2. This indicates that all three JNK isoforms promote SGN neurite growth although there may be functional redundancy between JNK1 and JNK2.

Reliability of Triggered EMG for Prediction of Safety during Pedicle Screw Placement in Adolescent Idiopathic Scoliosis Surgery.

STUDY DESIGN: We performed a prospective study to evaluate the reliability of using triggered electromyography (EMG) for predicting pedicle wall breakthrough during the placement of pedicle screw in adolescent idiopathic scoliosis surgery. PURPOSE: We wanted to correlate pedicle wall breakthrough with the triggered EMG threshold of stimulation and the postoperative computed tomography (CT) findings. OVERVIEW OF LITERATURE: Pedicle wall breakthrough has been reported to be difficult to evaluate by radiographs. Triggered EMG had been found to be a more sensitive test to detect this breakthrough. METHODS: Seven patients who underwent the insertion of 103 pedicle screws were evaluated. The triggered EMG activity was recorded from several muscles depending on the level of screw placement. The postoperative CT scans were read by a spine surgeon who was a senior fellow in orthopedics, and a musculoskeletal radiologist. RESULTS: The mean age at surgery was 12.6 years (range, 11 to 17 years). The preoperative mean Cobb angle was 54.7° (range, 45 to 65°). There were 80 thoracic screws and 23 lumbar screws. All the screws had stimulation thresholds of ≥ 6 mA, except 3 screws with the stimulation threshold of < 6 mA. Ten screws (9.7%) showed violation of the pedicle wall on the postoperative CT scans. Five screws penetrated medially and another five penetrated laterally. No postoperative neurologic complications were noted in any of the seven patients. CONCLUSIONS: Measuring the stimulation threshold of triggered EMG helps to assess the pedicle screw placement. Pedicle screws that had stimulation threshold of ≥ 6 mA were safe, with 90.3% reliability, as was assessed on the postoperative CT scans.

Better functional outcome of salvage THA than bipolar hemiarthroplasty for failed intertrochanteric femur fracture fixation.

Failure of intertrochanteric fracture fixation often occurs in patients who have poor bone quality, severe osteoporosis, or unstable fracture patterns. The purpose of this study is to compare the results of total hip arthroplasty (THA) with bipolar hemiarthroplasty as the salvage procedures for failed fixation of intertrochanteric fractures of the femur. Eighteen consecutive patients who were treated for failed intertrochanteric fracture fixation were reviewed retrospectively. The patients were divided into 2 groups of salvage procedures: THA (9 patients) and bipolar hemiarthroplasty (9 patients). In the THA group, mean Harris Hip Score (HHS), visual analog scale (VAS) score, and Salvati and Wilson score were 82.1, 0.9, and 31.3, retrospectively. In the bipolar hemiarthroplasty group, mean HHS, VAS score, and Salvati and Wilson score were 68.6, 3.1 and 25.1, retrospectively. Total hip arthroplasty was better than bipolar hemiarthroplasty treatment in HHS (P=.040), VAS score (P=.001), and Salvati and Wilson score (P=.033). There were no significant differences in hospital stay, operating time, and transfusion volume between the 2 groups. Total hip arthroplasty seems to be more reliable salvage procedure for failed intertrochanteric fracture fixation in functional outcome and pain relief.

Energy-based control of a haptic device using brakes.

This paper proposes an energy-based control method of a haptic device with electric brakes. Unsmooth motion is frequently observed in a haptic system using brakes during a wall-following task. Since it is generally known that a haptic system using brakes is passive due to brake's characteristics, its energy behavior has seldom been investigated. However, force distribution at the end effector reveals that the unsmooth motion of a haptic system using brakes represents active behavior of the system in the specific direction. A force control scheme is proposed that computes the gain for smooth motion by considering the energy behavior of a system. Experiments show that smooth wall following is possible with a proposed force control scheme.