Cross-sectional Area Research Articles

Different outcomes of endurance and resistance exercise in skeletal muscles of Oculopharyngeal muscular dystrophy.

Exercise is widely considered to have beneficial impact on skeletal muscle aging. In addition, there are also several studies demonstrating a positive effect of exercise on muscular dystrophies. Oculopharyngeal muscular dystrophy (OPMD) is a late-onset autosomal dominant inherited neuromuscular disorder caused by mutations in the PAPBN1 gene. These mutations consist in short (1-8) and meiotically stable GCN trinucleotide repeat expansions in its coding region responsible for the formation of PAPBN1 intranuclear aggregates. This study aims to characterize the effects of two types of chronic exercise, resistance and endurance, on the OPMD skeletal muscle phenotype using a relevant murine model of OPMD. In this study, we tested two protocols of exercise. In the first, based on endurance exercise, FvB (wild-type) and A17 (OPMD) mice underwent a 6-week-long motorized treadmill protocol consisting in three sessions per week of running 20cm/s for 20min. In the second protocol, based on resistance exercise generated by chronic mechanical overload (OVL), surgical removal of gastrocnemius and soleus muscles was performed, inducing hypertrophy of the plantaris muscle. In both types of exercise, muscles of A17 and FvB mice were compared with those of respective sedentary mice. For all the groups, force measurement, muscle histology, and molecular analyses were conducted. Following the endurance exercise protocol, we did not observe any major changes in the muscle physiological parameters, but an increase in the number of PABPN1 intranuclear aggregates in both tibialis anterior (+24%, **P=0.0026) and gastrocnemius (+18%, ****P<0.0001) as well as enhanced collagen deposition (+20%, **P=0.0064 in the tibialis anterior; +35%, **P=0.0042 in the gastrocnemius) in the exercised A17 OPMD mice. In the supraphysiological resistance overload protocol, we also observed an increased collagen deposition (×2, ****P<0.0001) in the plantaris muscle of A17 OPMD mice which was associated with larger muscle mass (×2, ****P<0.0001) and fibre cross sectional area (×2, ***P=0.0007) and increased absolute maximal force (×2, ****P<0.0001) as well as a reduction in PABPN1 aggregate number (-16%, ****P<0.0001). Running exercise and mechanical overload led to very different outcome in skeletal muscles of A17 mice. Both types of exercise enhanced collagen deposition but while the running protocol increased aggregates, the OVL reduced them. More importantly OVL reversed muscle atrophy and maximal force in the A17 mice. Our study performed in a relevant model gives an indication of the effect of different types of exercise on OPMD muscle which should be further evaluated in humans for future recommendations as a part of the lifestyle of individuals with OPMD.

Increased Homer Activity and NMJ Localization in the Vestibular Lesion het−/− Mouse soleus Muscle

We investigated the shuttling of Homer protein isoforms identified in soluble (cytosolic) vs. insoluble (membrane–cytoskeletal) fraction and Homer protein–protein interaction/activation in the deep postural calf soleus (SOL) and non-postural gastrocnemius (GAS) muscles of het−/− mice, i.e., mice with an autosomal recessive variant responsible for a vestibular disorder, in order to further elucidate a) the underlying mechanisms of disrupted vestibular system-derived modulation on skeletal muscle, and b) molecular signaling at respective neuromuscular synapses. Heterozygote mice muscles served as the control (CTR). An increase in Homer cross-linking capacity was present in the SOL muscle of het−/− mice as a compensatory mechanism for the altered vestibule system function. Indeed, in both fractions, different Homer immunoreactive bands were detectable, as were Homer monomers (~43–48 kDa), Homer dimers (~100 kDa), and several other Homer multimer bands (&gt;150 kDA). The het−/− GAS particulate fraction showed no Homer dimers vs. SOL. The het−/− SOL soluble fraction showed a twofold increase (+117%, p ≤ 0.0004) in Homer dimers and multimers. Homer monomers were completely absent from the SOL independent of the animals studied, suggesting muscle-specific changes in Homer monomer vs. dimer expression in the postural SOL vs. the non-postural GAS muscles. A morphological assessment showed an increase (+14%, p ≤ 0.0001) in slow/type-I myofiber cross-sectional area in the SOL of het−/− vs. CTR mice. Homer subcellular immuno-localization at the neuromuscular junction (NMJ) showed an altered expression in the SOL of het−/−mice, whereas only not-significant changes were found for all Homer isoforms, as judged by RT-qPCR analysis. Thus, muscle-specific changes, myofiber properties, and neuromuscular signaling mechanisms share causal relationships, as highlighted by the variable subcellular Homer isoform expression at the instable NMJs of vestibular lesioned het−/− mice.

Performance Evaluation of Different Rotating Detonation Combustor Designs Using Simulations and Experiments

Abstract Rotating Detonation Engines (RDEs) present a potential avenue for enhancing the efficiency of gas turbine combustors through the utilization of a detonation-driven process. However, integrating an RDE with a downstream turbine poses a significant challenge due to the shock-laden and highly unsteady nature of the RDE exit flow, coupled with a high degree of flow periodicity. In contrast, gas turbines are designed to operate with relatively small velocity and temperature fluctuations at the turbine inlet. The objective of the present study is to develop an understanding of how geometric profiling can improve RDE performance and mitigate exhaust flow field unsteadiness. Three RDE designs are analyzed: an annular combustor with a constant cross-sectional area, an annular combustor with a converging nozzle near the exit, and an annular combustor with a rapid to gradual (RTG) area convergence. Three-dimensional unsteady reacting simulations are conducted for each configuration using the same fuel-oxidizer composition and mass flow rate condition. All simulations are validated against experimental measurements, and RDE performance is assessed based on total pressure gain/loss, unsteadiness at the exit of the RDE, and detonation effectiveness. Results show significant performance improvement for both the convergent nozzle and the RTG profile compared to the constant cross-sectional area configuration, and the RTG design performed better than the convergent nozzle design. Therefore, strategically constricting the flow in an RDE can be used to optimize the performance of an RDE and should be considered in future designs.

23 Pre-surgical visceral adipose tissue may be a novel pre-surgical risk factor for acute kidney injury among clear cell renal cell cancer patients undergoing radical nephrectomy

Abstract Background Patients with renal cancer undergoing partial (PN) or radical nephrectomy (RN) are at risk for acute kidney injury (AKI). Established risk factor for AKI include baseline comorbidities (e.g., obesity, hypertension), normal renal parenchymal loss, and ischemia-reperfusion injury. Pre-surgical body composition may be an overlooked modifiable patient characteristic that influences risk of AKI. We hypothesized that patients with higher visceral adipose tissue quantity or lower skeletal muscle quantity would have a higher risk of AKI. Methods The RESOLVE study at Memorial Sloan Kettering Cancer Center is a retrospective study of 1239 patients with stage I-III clear cell renal cell carcinoma (ccRCC) undergoing PN or RN from 2000 to 2020. We excluded from analysis patients with solitary kidney, those without preoperative serum creatinine (sCr) measurements, and those without a sCr measurement within seven days following nephrectomy, yielding a study population of 1,200 ccRCC patients with longitudinal sCr assessment (n=754 PN; n=446 PN). AKI was defined as a binary variable using the Kidney Disease – Improving Global Outcomes (KDIGO) criteria, based on a threshold of either a 1.5x relative or 0.3 mg/dl absolute increase in sCr within seven days. The cross-sectional areas and radiodensities of visceral adipose and skeletal muscle tissues were determined from pre-surgical computed tomography (CT) scans at the third lumbar vertebrae using Automatica software. We used generalized linear models with a binomial family and identity link to estimate seven-day risk differences (RD) and 95% confidence intervals in subgroups defined by surgery type. Results AKI was more frequent among patients undergoing RN (66% vs 26% among PN). Male patients, those with higher eGFR prior to surgery, those with lower stage/smaller tumors, and those with a history of hyperlipidemia more frequently experienced AKI in the post-operative period. No associations were observed with other reported comorbidities (diabetes, hypertension). While no association was observed between BMI and risk of AKI, visceral adipose and skeletal muscle variables were significantly associated with risk of AKI in univariate models. After adjustment for age, sex, comorbidities, and other body composition variables, only higher visceral adipose tissue quantity remained significantly associated with increased risk of AKI [RD per 40 unit increase (95% CI): 5.2 (1.3, 9.2)]. Muscle characteristics were not associated with AKI in multivariable models. Among patients undergoing PN, we observed a higher frequency of AKI among male patients, those with higher stage/larger tumors, and those with longer ischemia times. No significant associations were observed with comorbidity histories. In univariate models, visceral adipose tissue quantity and quality as well as skeletal muscle quantity were associated with AKI risk; however, after adjustment for age, sex, comorbidities, and other body composition variables, we observed no significant associations between any body composition feature and AKI in patients undergoing PN. Conclusions Associations between pre-surgical body composition and risk of AKI vary by surgery type. Visceral adipose tissue quantity was associated with risk of AKI among patients undergoing RN, but not PN. This finding may be relevant for patient counseling, consideration for nephron-sparing surgery, and development of interventions to lower visceral adipose tissue quantity. Future studies should evaluate the impact of both pre-surgical and post-surgical change in body composition in relation on chronic kidney disease after nephrectomy.

Determination of causes of post-operative dysphagia after anti-reflux surgery based on intra-operative planimetry.

Dysphagia after anti-reflux surgery (ARS) is one of the most common indications for re-operative anti-reflux surgery and a leading cause of patient dissatisfaction. Unfortunately, the factors affecting its development are poorly understood. We investigated the correlation between pre-operative manometric and the intra-operative impedance planimetry (EndoFLIP™) measurements and development of post-operative dysphagia. A review of patients who underwent index robotic ARS in our institution. Patients who underwent pre-operative manometry and intra-operative EndoFLIP™ were included in our study. Dysphagia was assessed pre-operatively and at 3-month after surgery. Fifty-five patients (26.9%) reported post-operative dysphagia, and 34 (16.6%) reported new or worsening dysphagia. On pre-operative manometry, patients with post-operative dysphagia had a lower distal contractile integral [868.7 (IQR 402.2-1447) mmHg s cm vs 1207 (IQR 612.1-2111) mmHg s cm, p = 0.006) and lower esophageal sphincter (LES) pressure [14.7 IQR (8.9-23.6) mmHg vs 20.7 IQR (10.2-32.6) mmHg, p = 0.01] compared to those without post-operative dysphagia. They were also found to have higher pre-operative cross-sectional surface area (CSA) [83 IQR (44.5-112) mm2 vs 66 IQR (42-93) mm2, p = 0.02], and distensibility index (DI) [4.2 IQR (2.2-5.5) mm2/mmHg vs 2.9 IQR (1.6-4.6) mm2/mmHg, p = 0.003] compared to patients without post-operative dysphagia. Additionally, the decrease in CSA [-34 (-18.5, -74.5) mm2 vs -26.5 (-10.5, -53.7) mm2, p = 0.03] and DI [-2.3 (-1.2, -3.7) mm2/mmHg vs -1.6 (-0.7, -3.3) mm2/mmHg, p = 0.03] measurements were greater in patients with post-operative dysphagia. Patients who developed dysphagia post-operatively had poorer pre-operative motility and a greater change in LES characteristics intra-operatively. This finding suggests the utility of pre-operative manometry and intra-operative EndoFLIP in identifying patients at risk of developing dysphagia post-operatively.

53 Associations between body composition, ClearCode34, and clinical outcomes in localized clear cell renal cell carcinoma

Abstract Background Emerging evidence suggests that pre-surgical body composition is a prognostic factor for cancer outcomes. Lower skeletal muscle quantity and radiodensity have been associated with renal cell carcinoma (RCC) outcomes in other studies, while reports of the relationship between visceral adipose tissue and RCC outcomes have been inconsistent. Mechanisms underlying these associations are unclear but may relate to tumor biology. We leveraged a large molecular epidemiology study of localized clear cell renal cell carcinoma (ccRCC) patients to examine how pre-surgical body composition features were associated with survival post-nephrectomy as well as ClearCode34 status, a previously validated prognostic gene expression signature. Methods The RESOLVE study at Memorial Sloan Kettering Cancer Center is a retrospective study of 1,239 patients with stage I-III ccRCC undergoing nephrectomy without systemic therapy. Pre-surgical CT scans at the third lumbar vertebrae were segmented for the cross-sectional areas and radiodensities of skeletal muscle, subcutaneous adipose and visceral adipose tissues using Automatica software. Formalin-fixed, paraffin-embedded tumor tissue samples were available for 929 patients, which were sent to the University of North Carolina at Chapel Hill and assayed for gene expression. RNA was extracted from these samples and analyzed using the Nanostring nCounter system on a custom panel of 356 genes, including the 34 genes used in the ClearCode34 assay. Of the 929 patients with tumor tissue available, gene expression data from 837 patients (90.1%) passed RNA extraction and data QC. Samples were classified into either ccA or ccB ClearCode34 classes using a reference data set and PAM (prediction analysis of microarrays) centroid-based classification. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for disease-free survival (DFS) within five years of diagnosis using Cox proportional hazards models for both body composition variables and ClearCode34 subtype. We also estimated odds ratios (ORs) and 95% CIs for associations between ClearCode34 subtype and body composition with logistic regression. All multivariable models were adjusted for age, sex, and all body composition variables. Results Of the 837 patients in our analytic sample, 219 (26%) had ccB tumors. Men, patients with high stage or grade tumors, and patients with chronic kidney disease prior to nephrectomy were more likely to present with ccB tumors. Lower skeletal muscle density (SMD) was significantly associated with lower five-year DFS [HR (95% CI) per 10 HU decrease in SMD: 1.7 (1.2, 2.3)]. While no other body composition features were significantly associated, we also observed non-significantly increased HRs for VATI and VATD [HR (95% CIs): 1.3 (0.8, 2.0) and 1.5 (0.9, 2.7), respectively]. ClearCode34 subtype was significantly associated with five-year DFS, where patients with ccB tumors had poorer DFS [HR (95% CI): 1.7 (1.1, 2.5)] compared to patients with ccA tumors. Notably, we observed no significant associations between any body composition feature and ClearCode34 in univariable analyses. However, in multivariable models that accounted for all body composition variables simultaneously as well as age and sex, lower SMD emerged as significantly associated with ccB subtype [OR (95% CI) per 10 HU decrease in SMD: 1.3 (1.0, 1.7)]. Conclusions Our findings suggest that the associations observed between body composition features and clinical outcomes in ccRCC may be related to tumor biology. Lower pre-surgical SMD, which may represent myosteatosis and metabolic dysregulation in ccRCC patients, was associated with both decreased five-year DFS and an increased likelihood of presenting with a more aggressive ccB tumor. Future studies should investigate body composition features related to ccRCC prognosis and additional markers of tumor biology, such as immune-related gene expression patterns, to extend these findings.

Performance of structural insulation panels under eccentric axial and racking loads with varying opening ratios

Structural insulation panels, which are actively applied in the housing market in North America and Europe by utilizing wood, an eco-friendly material, as the main material, are composed of OSB (Oriented Strand Board), EPS (Expanded Polystyrene), and SPF (Spruce-Pine-Fir), which is used as a connection between the panels. Structural insulated panels are used as a load-bearing wall to resist external forces without installing separate columns. The production of structural insulation panels consists of applying adhesive to both sides of EPS, which acts as an insulation material, and pressing wood boards (OSB), which exert strength as a structural material. The OSB on the outside resists compressive and tensile forces, while the EPS on the inside resists shear forces. The joints and openings of the structural insulation panels are reinforced with SPF (Spruce-Pine-Fir) structural wood. When structural insulated panels are used as an exterior wall structure, the installation of openings is essential. Based on the opening size that is popularly used in wooden structures, the performance evaluation of structural insulation panels under eccentric axial load and repeated lateral load due to the reduction of the cross-sectional area by installing the opening was carried out, and the behavior analysis through variable analysis and comparison analysis with the design equation was carried out.

Sarcopenia shortens overall survival of patients with platinum-resistant recurrent ovarian cancer: inverse probability of treatment-weighting analysis

ObjectiveThe association between sarcopenia and prognosis in patients with platinum-resistant recurrent ovarian cancer remains unclear. This study investigated whether sarcopenia is a prognostic factor in patients with platinum-resistant recurrent ovarian...

Minimalist school shoes improve intrinsic foot muscle size, strength, and arch integrity among primary school students

ABSTRACT Minimalist walking shoes have been shown to improve foot muscle size and strength in active adults, but not in our previous study involving children, which could relate to the more structured footwear used in our study. Hence, this study examined the effects of true minimalists on intrinsic foot muscle size and strength, foot arch integrity, and physical function among primary school children. After a baseline assessment, 30 primary school students aged between 9 and 12 were given a pair of minimalist shoes (minimalist index = 92%) as their regular school shoes for two school terms, followed by a re-assessment. Seventeen of the 30 participants in the minimalist group completed the study. Compared to the control group, the minimalist group showed significantly increased cross-sectional area of abductor hallucis (p = 0.047, Cohen’s d = 0.57) and flexor digitorum brevis (p = 0.037, Cohen’s d = 0.80), increased strength of the hallux (p = 0.015, Cohen’s d = 0.76) and lesser toes (p = 0.014, Cohen’s d = 0.66), greater arch height (p = 0.020, Cohen’s d = 0.52) and standing long jump distance (p = 0.001, Cohen’s d = 9.79). The control group exhibited improved standing long jump performance only (p = 0.020, Cohen’s d = 10.70). Minimalist shoes worn daily to school promote intrinsic foot muscle size and strength, and improve foot arch integrity among primary school students.

Open-jet facility for bio-inspired micro-air-vehicle flight experiment at low speed and high turbulence intensity

Bio-inspired micro-air-vehicles (MAVs) usually operate in the atmospheric boundary layer at a low Reynolds number and complex wind conditions including large-scale turbulence, strong shear, and gusts. We develop an open jet facility (OJF) to meet the requirements of MAV flight experiments at very low speed and high turbulence intensity. Powered by a stage-driven fan, the OJF is capable of generating wind speeds covering 0.1 – 16.8 m/s, with a velocity ratio of 100:1. The contraction section of the OJF is designed using an adjoint-driven optimization method, resulting in a contraction ratio of 3:1 and a length-to-diameter ratio of 0.75. A modularized design of the jet nozzle can produce laminar or high-turbulence wind conditions. Flow field calibration results demonstrate that the OJF is capable of producing a high-quality baseline flow with steady airspeed as low as 0.1 m/s, uniform region around 80% of the cross-sectional test area, and turbulence intensity around 0.5%. Equipped with an optimized active grid (AG), the OJF can reproduce controllable, fully-developed turbulent wind conditions with the turbulence intensity up to 24%, energy spectrum satisfying the five-thirds power law, and the uniform region close to 70% of the cross-sectional area of the test section. The turbulence intensity, integral length scale, Kolmogorov length scale, and mean energy dissipation rate of the generated flow can be adjusted by varying the area of the triangular through-hole in the wings of the AG.

Age-related differences in the loss and recovery of serial sarcomere number following disuse atrophy in rats

BackgroundOlder adults exhibit a slower recovery of muscle mass following disuse atrophy than young adults. At a smaller scale, muscle fibre cross-sectional area (i.e., sarcomeres in parallel) exhibits this same pattern. Less is known, however, about age-related differences in the recovery of muscle fibre length, driven by increases in serial sarcomere number (SSN), following disuse. The purpose of this study was to investigate age-related differences in SSN adaptations and muscle mechanical function during and following muscle immobilization. We hypothesized that older adult rats would experience a similar magnitude of SSN loss during immobilization, however, take longer to recover SSN than young following cast removal, which would limit the recovery of muscle mechanical function.MethodsWe casted the plantar flexors of young (8 months) and old (32 months) male rats in a shortened position for 2 weeks, and assessed recovery during 4 weeks of voluntary ambulation. Following sacrifice, legs were fixed in formalin for measurement of soleus SSN and physiological cross-sectional area (PCSA) with the un-casted soleus acting as a control. Ultrasonographic measurements of pennation angle (PA) and muscle thickness (MT) were conducted weekly. In-vivo active and passive torque-angle relationships were constructed pre-cast, post-cast, and following 4 weeks of recovery.ResultsFrom pre- to post-cast, young and older adult rats experienced similar decreases in SSN (–20%, P < 0.001), muscle wet weight (–25%, P < 0.001), MT (–30%), PA (–15%, P < 0.001), and maximum isometric torque (–40%, P < 0.001), but there was a greater increase in passive torque in older (+ 180%, P < 0.001) compared to young adult rats (+ 68%, P = 0.006). Following cast removal, young exhibited quicker recovery of SSN and MT than old, but SSN recovered sooner than PA and MT in both young and old. PCSA nearly recovered and active torque fully recovered in young adult rats, whereas in older adult rats these remained unrecovered at ∼ 75%.ConclusionsThis study showed that older adult rats retain a better ability to recover longitudinal compared to parallel muscle morphology following cast removal, making SSN a highly adaptable target for improving muscle function in elderly populations early on during rehabilitation.

Validation of an automated segmentation method for body composition analysis in colorectal cancer patients using diagnostic abdominal computed tomography images.

Background & AimsSeveral automated programs have been developed to facilitate body composition analysis of images from abdominal computed tomography (CT) scans. External validation in patients with colorectal cancer is necessary for use in research and clinical practice. Our aim was to validate an automatic method (AutoMATiCA) of segmenting CT images at the third lumbar level (L3) from patients with colorectal cancer, by comparing with manual segmentation. MethodsDiagnostic abdominal CT scans of consecutive patients with stage I-III colorectal cancer were analysed to measure cross-sectional areas and tissue densities of skeletal muscle and intra-muscular, visceral, and subcutaneous adipose tissue. Trained analysts performed manual segmentation of L3 CT images using SliceOmatic. Automatic segmentation was performed using AutoMATiCA, an open-source software. The Dice similarity coefficient (DSC) was calculated to assess segmentation accuracy. Agreement of automatic with manual segmentation was evaluated using intra-class correlation coefficients (ICCs) and Bland-Altman plots with limits of agreement. ResultsA total of 292 scans were included, of which 62% were from male patients. The agreement of AutoMATiCA with the manual segmentation was excellent, with median DSC values ranging from 0.900-0.991 and ICCs above 0.95 for all segmented areas. No systematic deviations were observed in Bland-Altman plots for all segmented areas, with overall narrow limits of agreement. ConclusionsAutoMATiCA provides an accurate segmentation of abdominal CT images from patients with colorectal cancer. Our findings support its use as a highly efficient automated tool for body composition analysis in research and potentially also in clinical practice.

Reliability of Ultrasound Assessment of Hamstring Morphology, Quality, and Stiffness Among Healthy Adults and Athletes: A Systematic Review.

The incidence and recurrence rate of hamstring strain injuries remain persistently high, with recurrent injuries leading to increased time lost during play and extended recovery periods compared with initial injury. Ultrasound imaging assesses important factors such as hamstring fascicle length (FL), pennation angle (PA), cross-sectional area (CSA), muscle thickness (MT), echo intensity (EI), and shear wave elastography (SWE), all impacting athletic performance. However, its reliability must be established before employing any measurement tool in research or clinical settings. To determine the reliability and measurement error of ultrasound for assessing hamstring FL, PA, CSA, MT, EI, and SWE among healthy adults and athletes; to synthesize the information regarding the operationalization of ultrasound. A systematic literature search was done from January 1990 to February 5, 2023, to identify reliability and validity studies of hamstring ultrasound assessment published in peer-reviewed journals with identifiable methodology of outcome measures. Intraclass correlation coefficient measurement of 14 included studies reported moderate to excellent intrarater, interrater, and test-retest reliabilities of FL, PA, and MT regardless of the site of muscle testing, probe size, and setting, state of muscle, and use of different techniques in the extrapolation of FL. Good to excellent test-retest reliability rates for all hamstring anatomic CSA along midmuscle and different percentages of thigh length using panoramic imaging. Good intrarater reliability of EI regardless of gender and orientation of the probe but with excellent intrarater reliability in transverse scan using maximum region of interest. Good intrarater, interrater, and interday repeatability on SWE with the muscle in a stretched position. Evidence from studies with a predominantly low risk of bias shows that ultrasound is a reliable tool to measure hamstring FL, PA, CSA, MT, EI, and SWE in healthy adults and athletes under various experimental conditions.

Atlantoaxial intra-articular cage fusion by posterior intermuscular approach for treating reducible atlantoaxial dislocation: a technique note with case series.

To evaluate the clinical feasibility of atlantoaxial intra-articular cage (AIC) fusion via intermuscular approach for treating reducible atlantoaxial dislocation (AAD). An analysis was conducted on the data of 10 patients who underwent C1-C2 segmental fixation and AIC fusion for AAD by unilateral intermuscular approach and contralateral open approach. Outcome assessments included Japanese Orthopaedic Association score (JOA) and Visual Analog Scale Score for Neck Pain (VASSNP). The duration of surgical exposure, screw insertion and cage insertion, and postoperative drainage volume were also compared between two approaches. Bone fusion was evaluated through computed tomography (CT) reconstruction. Postoperative paravertebral tissue edema was evaluated by paravertebral tissue cross-sectional area (CSA) and signal intensity on T2 weighted sequence of magnetic resonance imaging (MRI) at 3 days postoperatively. The intermuscular approach exhibited a longer exposure time but lower drainage postoperatively compared to the open approach (P < 0.05). After operation, JOA scores significant improved (P < 0.05), while VASSNP scores significantly decreased (P < 0.05). There was no significant difference in preoperative CSA between two approaches (P > 0.05). However, compared to the open approach, the intermuscular approach exhibited less CSA (P < 0.05) and lower T2 signal intensity on MRI postoperatively, indicating less invasive to the paravertebral tissues. AIC fusion by intermuscular approach is an effective and safe technique in the treatment of reducible AAD. Intermuscular approach could reduce the postoperative drainage volume and the extent of paravertebral tissue edema compared to open approach.

Photodiode-Based Porosity Prediction in Laser Powder Bed Fusion Considering Inter-Hatch and Inter-Layer Effects

Laser powder bed fusion, while promising, faces hurdles in certifying fabricated parts due to cost and complexity, with in-process monitoring emerging as a potential solution. Existing models focus on predicting defects at a given location using the monitoring signals from solely that same location. Hence, these models treat each track or layer independently of the previous and subsequent ones, neglecting potential interdependencies. This study proposed an in-situ, photodiode-based monitoring approach considering inter-hatch and inter-layer effects on porosity formation - factors often overlooked in existing research. Two Ti-6Al-4V cuboids (10×10×5 mm3) were built with optimized process parameters, with the melt pool continuously monitored at 20kHz via a co-axially mounted photodiode. The monitoring system captured the integral radiation in the near-infrared spectrum within a field of view centered on the melt pool. The porosity is assessed by X-ray computed tomography (X-CT), serving as ground truth to build supervised machine learning (ML) models. This study considered physical phenomena occurring during the printing process, including remelting of lack of fusion pores by the subsequent layer, keyholes penetrating the current layer hence introducing pores in the layer below, and overlap between adjacent scan tracks. These considerations are critical for a holistic understanding of pore formation mechanisms. Photodiode signals and computed tomography volumes were cropped using windows of four sizes to test the model's pore localization capability. A machine learning model, specifically a Convolutional Neural Network (CNN) - Long Short-Term Memory (LSTM) network, was trained to predict porosities using these window sequences. The CNN extracted spatial features from photodiode signals, addressing inter-hatch effects, while the LSTM captured temporal dependencies across layers, addressing inter-layer effects. The results, with the Area Under the Receiver Operating Characteristic curve (AUC) of 0.91 for pores exceeding 8000 μm3 in volume and 100 μm2 in cross-sectional area, demonstrate the feasibility of the proposed model in detecting pores-level defects. This high defect prediction and positioning accuracy are essential for process control, providing real-time status of the region of interest and informing the controller of pore positions, thus facilitating intra-layer or inter-layer correction.

Characterizing white matter connectome abnormalities in patients with temporal lobe epilepsy using threshold-free network-based statistics.

Emerging evidence illustrates that temporal lobe epilepsy (TLE) involves network disruptions represented by hyperexcitability and other seizure-related neural plasticity. However, these associations are not well-characterized. Our study characterizes the whole brain white matter connectome abnormalities in TLE patients compared to healthy controls (HCs) from the prospective Epilepsy Connectome Project study. Furthermore, we assessed whether aberrant white matter connections are differentially related to cognitive impairment and a history of focal-to-bilateral tonic-clonic (FBTC) seizures. Multi-shell connectome MRI data were preprocessed using the DESIGNER guidelines. The IIT Destrieux gray matter atlas was used to derive the 162×162 structural connectivity matrices (SCMs) using MRTrix3. ComBat data harmonization was applied to harmonize the SCMs from pre- and post-scanner upgrade acquisitions. Threshold-free network-based statistics were used for statistical analysis of the harmonized SCMs. Cognitive impairment status and FBTC seizure status were then correlated with these findings. We employed connectome measurements from 142 subjects, including 92 patients with TLE (36 males, mean age=40.1±11.7 years) and 50 HCs (25 males, mean age=32.6±10.2 years). Our analysis revealed overall significant decreases in cross-sectional area (CSA) of the white matter tract in TLE group compared to controls, indicating decreased white matter tract integrity and connectivity abnormalities in addition to apparent differences in graph theoretic measures of connectivity and network-based statistics. Focal and generalized cognitive impaired TLE patients showcased higher trend-level abnormalities in the white matter connectome via decreased CSA than those with no cognitive impairment. Patients with a positive FBTC seizure history also showed trend-level findings of association via decreased CSA. Widespread global aberrant white matter connectome changes were observed in TLE patients and characterized by seizure history and cognitive impairment, laying a foundation for future studies to expand on and validate the novel biomarkers and further elucidate TLE's impact on brain plasticity.

Is the disappearance of the cervical flexion-relaxation phenomenon associated with cervical degeneration in healthy people?

This study aims to explore the differences in cervical degeneration between healthy people with and without cervical flexion-relaxation phenomenon (FRP) and to identify whether the disappearance of cervical FRP is related to cervical degeneration. According to the flexion relaxation ratio (FRR), healthy subjects were divided into the normal FRP group and the abnormal FRP group. Besides, MRI was used to evaluate the degeneration of the passive subsystem (vertebral body, intervertebral disc, cervical sagittal balance, etc.) and the active subsystem (deep flexors [DEs], deep extensors [DFs], and superficial extensors [SEs]). In addition, the correlation of the FRR with the cervical degeneration score, C2-7Cobb, Borden method, relative total cross-sectional area (rTCSA), relative functional cross-sectional area (rFCSA), and fatty infiltration ratio (FIR) was analyzed. A total of 128 healthy subjects were divided into the normal FRP group (n=52, 40.63%) and the abnormal FRP group (n=76, 59.38%). There were significant differences between the normal FRP group and the abnormal FRP group in the cervical degeneration score (z=-6.819, P<0.001), C2-7Cobb (t=2.994, P=0.004), Borden method (t=2.811, P=0.006), and FIR of DEs (t=-4.322, P<0.001). The FRR was significantly correlated with the cervical degeneration score (r=-0.457, P<0.001), C2-7Cobb (r=0.228, P=0.010), Borden method (r=0.197, P=0.026), and FIR of DEs (r=-0.253, P=0.004). The disappearance of cervical FRP is related to cervical degeneration. A new hypothesis mechanism for FRP is proposed. The cervical FRP test is an effective and noninvasive examination for the differential diagnosis of healthy people, people with potential NSNP, and patients with NSNP.

Ascending geometry after thoracic endovascular aortic repair for descending aortic dissection

ObjectivesThis study aimed to assess geometry changes of the ascending aorta after thoracic endovascular aortic repair (TEVAR) for descending aortic dissection and identify potential risk factors for diameter and length change. MethodsBetween 04/2009 and 07/2021, 102 patients were treated for acute descending aortic dissections (Type B and non-A non-B) with TEVAR and were included in this analysis. Computed tomography angiographic scans were transferred to a dedicated imaging software and detailed aortic measurements (including length, diameter and area) were taken in multiplanar reconstruction postoperatively, after six months and annually thereafter. ResultsSixty-five (58%) patients were male, with a mean age of 66 (±11). Four (4%) patients were diagnosed with a connective tissue disease. Before TEVAR, 79% of our patients were treated with a mean of 1.5 (±1.2) different classes of antihypertensive medications. This number rose to 98% after TEVAR and 2.7 (±1.0) different antihypertensive drugs. There was no significant change in length, diameter, cross-sectional area, or volume of the ascending aorta during the follow-up of 3 years after TEVAR. Body height was a negative predictor for mean ascending aortic diameter (p-value = -0.013; B = -8.890) and mean aortic diameter at the level of the brachiocephalic trunk (p-value = 0.039; B = -14.763). ConclusionsOur data suggests no significant changes in the ascending aorta following TEVAR of the descending thoracic aorta during mid-term follow-up when under stringent blood pressure medication. Additionally, we did not find any modifiable risk factors for geometry parameter increase.

Numerical studies on the performance of Savonius turbines for hydropower application by varying the frontal cross-sectional area

The Savonius turbine is a drag-based device that utilizes hydrokinetic energy in irrigation channels for small-scale hydropower generation. Since it is a drag-type device, the turbine blade frontal cross-sectional area influences the performance of the turbine blade. In this paper, the influence of taper on the turbine blade bottom, top, and middle sides on the Savonius turbine performance was computed numerically using the sliding mesh technique with a 0.5 m/s water inlet velocity. In this study, the effect of various blades with varying cross-sectional areas has been analyzed numerically using the sliding mesh technique, and the results were compared with the semicircular blade profile. The variation of torque coefficient with respect to rotor blade rotation was plotted, and pressure and velocity variation were analyzed to investigate the performance parameters. The results showed that the top small, middle high, and bottom small blade profiles performed better than the semicircular, inverted taper and top high, middle small, and bottom high blade profiles. It is observed that the maximum torque coefficient at a TSR of 0.7 is 0.35, and the maximum power coefficient at a TSR of 0.9 is 0.253.

Evaluation of cervical spinal cord atrophy using a modified SIENA approach

Spinal cord (SC) atrophy obtained from structural magnetic resonance imaging has gained relevance as an indicator of neurodegeneration in various neurological disorders. The common method to assess SC atrophy is by comparing numerical differences of the cross-sectional spinal cord area (CSA) between time points. However, this indirect approach leads to considerable variability in the obtained results. Studies showed that this limitation can be overcome by using a registration-based technique.The present study introduces the Structural Image Evaluation using Normalization of Atrophy on the Spinal Cord (SIENA-SC), which is an adapted version of the original SIENA method, designed to directly calculate the percentage of SC volume change over time from clinical brain MRI acquired with an extended field of view to cover the superior part of the cervical SC.In this work, we compared SIENA-SC with the Generalized Boundary Shift Integral (GBSI) and the CSA change. On a scan-rescan dataset, SIENA-SC was shown to have the lowest measurement error than the other two methods. When comparing a group of 190 Healthy Controls with a group of 65 Multiple Sclerosis patients, SIENA-SC provided significantly higher yearly rates of atrophy in patients than in controls and a lower sample size when measured for treatment effect sizes of 50%, 30% and 10%.Our findings indicate that SIENA-SC is a robust, reproducible, and sensitive approach for assessing longitudinal changes in spinal cord volume, providing neuroscientists with an accessible and automated tool able to reduce the need for manual intervention and minimize variability in measurements.