Changes In Cross-sectional Area Research Articles

Comparison of femoral neck geometric parameters between Chinese and Japanese females.

Femoral neck fracture is the most serious osteoporotic fractures that is responsible for high medical costs and high mortality. Femoral neck geometric parameters (FNGPs) are important parameters that reflect the geometrical characteristics of femoral neck, and are closely related to the strength of femoral neck and the risk of fragility fracture.There are differences in the incidence of femoral neck fractures among races. However, whether there is difference in FNGPs among races is unknown.Therefore, this study aims to compare the differences in FNGPs between Chinese and Japanese females. This study was a cross-sectional study, in which 3 859 healthy females aged 10-86 (45.7±17.1) years old were recruited from Changsha City of Hunan Province and surrounding areas. The weight and height were measured and recorded, and the body mass index (BMI) was calculated. A dual energy X-ray absorptiometry (DXA) bone densitometer was used to measure femoral neck projective bone area (BA) and bone mineral density (BMD). FNGPs were calculated using the BMD and BA, which included the outer diameter (OD), cross-sectional area (CSA), cortical thickness (CT), endocortical diameter (ED), buckling ratio (BR), section modulus (SM), cross-sectional moment of inertia (CSMI), and compression strength index (CSI). The data of FNGPs in Japanese females was collected from literature. These subjects were grouped by 10-year age. The mean and standard deviation of height, weight, BMI, femoral neck BMD, and FNGPs of each group were calculated. The model with the best goodness-of-fit was selected from various mathematical regression models to analyze the distribution trend and the best fitting curve of FNGPs with age. The differences in FNGPs between Chinese and Japanese females were analyzed by using age-corresponding mean fitting curve for paired t-test, and the relative change rates of FNGPs were compared. The mean values of FNGPs were significantly different among different years old healthy females (all P<0.01). The mean values of OD, CSA, CT, SM, and CSMI in femoral neck were high at 30 to 39 years old, and then they were gradually decreased with age. The CSI reached its peak at 20-29 years old, and it was decreased gradually after 30 years old. ED and BR were at a low level before 40 years old, they were gradually increased after 40 years old, and reached the maximum average value at 80-86 years old. The variations in FNGPs with age were fitted with the best goodness-of-fit by applying the cubic regression model and the determination coefficients of regression equations (R2: 0.062-0.404) were significant (all P<0.01). The distribution trend of FNGPs with age varied with the indices, among which CSA, CT, SM, CSMI and CSI were increased with age before 35 years old, and then they were decreased with age; BR was at a low level in the early stage, and then it was increased with age after about 40 years. There were significant differences in the fitting curves of FNGPs related to age between Chinese and Japanese females (all P<0.01). The fitting curves of OD, ED, BR and SM in Chinese females were significantly higher than those in Japanese females (all P<0.01), while those of CSA and CT in Chinese females were significantly lower than those in Japanese females (all P<0.01). Before the age of 50, the curves of CSMI and CSI of Chinese females were significantly higher than those of Japanese females (all P<0.01), while after the age of 60 the situation was reversed (all P<0.01). Except for SM and CSI, there were significant differences in the rate of OD, CSA, CT, ED, BR and CSMI with age (all P<0.01). By the age of 80 years old, the rates of change in OD, ED, and BR with the age in Chinese females were increased by 0.91%,3.94%, and 47.5%, respectively, while those in Japanese females were increased by 8.57%, 15.8% and 85.3%, respectively；the rates of change of CSA, CT, and CSMI with the age in Chinese females were declined 28.0%, 29.6%, and 25.2%, respectively, while those in Japanese females were declined 29.9%, 36.2%, and 10.9%, respectively. There were significant difference in the rates of change in FNGPs with the age between Chinese and Japanese females (all P<0.01). The study reveals the variation of FNGPs with age in Chinese, and confirms that there are racial differences in FNGPs between Chinese and Japanese females, which may be one of the important reasons for the difference in the incidence of femoral neck fracture between Chinese and Japanese females.

Early Changes of Hamstrings Morphology and Contractile Properties during 10 d of Complete Inactivity.

The hamstrings (HS) muscle group plays a fundamental role in maintaining knee stability, thus contributing to the prevention and rehabilitation of lower limb musculoskeletal injuries. However, little is known about HS structural and functional adaptations after periods of prolonged inactivity. Our purpose was to investigate the HS morphological and contractile properties changes during 10 d of bed rest (BR). Ten young healthy males underwent a 10-d BR. HS cross-sectional area (CSA) (at 30%, 50%, and 70% of femur length) and biceps femoris long head (BFlh) architecture were assessed by ultrasound imaging after 0 d (BR0), 2 d (BR2), 4 d (BR4), 6 d (BR6), and 10 d (BR10) of BR, whereas BFlh contractile properties (radial twitch displacement [Dm] and contraction time [Tc]) were evaluated at the same time points by tensiomyography. HS muscle volume was assessed by magnetic resonance imaging at BR0 and BR10. A reduction in muscle volume was observed in BFlh ( P = 0.002; Δ = -3.53%), biceps femoris short head ( P = 0.002; Δ = -3.54%), semitendinosus ( P = 0.002; Δ = -2.63%), semimembranosus ( P = 0.002; Δ = -2.01%), and HS pooled together ( P < 0.001; Δ = -2.78%). Early changes in CSA were detected at 30% femur length already at BR6 for BFlh ( P = 0.009; Δ = -2.66%) and biceps femoris short head ( P = 0.049; Δ = -1.96%). We also found a reduction in fascicle length at BR6 ( P = 0.035; Δ = -2.44%) and BR10 ( P < 0.001; Δ = -2.84%). Dm and Tc increased at BR2 ( P = 0.010; Δ = 30.0%) and B10 ( P = 0.019; Δ = 19.7%), respectively. Despite being a nonpostural muscle group, HS exhibited a moderate reduction in muscle dimensions in response to a short unloading period. Small changes in BFlh fascicle length were also observed, accompanied by alterations in BFLh contractile properties. These HS modifications should not be ignored from a clinical perspective.

Effects of Blood Flow Restriction Combined With Resistance Training or Neuromuscular Electrostimulation on Muscle Cross-Sectional Area.

Low-load resistance training (LL) and neuromuscular electrostimulation (NES), both combined with blood flow restriction (BFR), emerge as effective strategies to maintain or increase muscle mass. It is well established that LL-BFR promotes similar increases in muscle cross-sectional area (CSA) and lower rating of perceived exertion (RPE) and pain compared with traditional resistance training protocols. On the other hand, only 2 studies with conflicting results have investigated the effects of NES-BFR on CSA, RPE, and pain. In addition, no study directly compared LL-BFR and NES-BFR. The aim of the study was to compare the effects of LL-BFR and NES-BFR on vastus lateralis CSA, RPE, and pain. Individual response for muscle hypertrophy was also compared between protocols. Intrasubject longitudinal study. University research laboratory. Fifteen healthy young males (age = 23 [5]y; weight = 77.6 [11.3]kg; height = 1.76 [0.08]m). Vastus lateralis CSA was measured through ultrasound at baseline (pre) and after 20 training sessions (post). The RPE and pain responses were obtained through modified 10-point scales, handled during all training sessions. Both protocols demonstrated significant increases in muscle CSA (P < .0001). However, the LL-BFR demonstrated significantly greater CSA changes compared with NES-BFR (LL-BFR = 11.2%, NES-BFR = 4.6%; P < .0001). Comparing individual increases in CSA, 12 subjects (85.7% of the sample) presented greater muscle hypertrophy for LL-BFR than for the NES-BFR protocol. In addition, LL-BFR produced significantly lower RPE and pain responses (P < .0001). The LL-BFR produced significantly greater increases in CSA with significant less RPE and pain than NES-BFR. In addition, LL-BFR resulted in greater individual muscle hypertrophy responses for most subjects compared with NES-BFR.

Optimization of Heat Transfer Rate in Fins by CAE

Abstract: Overheating and excessive increase in the temperature of the compressors body causes thermal loading on the compressors surfaces. The life of the compressor mainly depends upon the abrupt change in the thermal stresses and the pressure stress induced in the body. The life of the compressor can be successfully improved and optimized by working on the compressor body. Specifically speaking the compressors fin areas is the heat affected area. Change in small cross section area can significantly change the convective heat transfer. This project report focuses on providing economical methods which are optimized and also easily implementable solutions in the existing manufacturing setup. The above techniques are implemented on compressor head body. All possible attempts are made to change the cross section and the shape of the heat transfer areas so that maximized heat transfer reached in the operating process. The implementation of the optimize techniques is carried out by analyzing different cross sections such as straight, trapezoidal and parabolic. The scope of revising the strategies ultimately helps to increase productivity, efficiency, pointing to increase the profit. The only aim to propose the solution is to optimize the heat transfer rate by the change in the design.

Review: Enhancement of Heat Transfer through Modification in Fins

Abstract: Overheating and excessive increase in the temperature of the compressors body causes thermal loading on the compressors surfaces. The life of the compressor mainly depends upon the abrupt change in the thermal stresses and the pressure stress induced in the body. The life of the compressor can be successfully improved and optimized by working on the compressor body. Specifically speaking the compressors fin areas is the heat affected area. Change in small cross section area can significantly change the convective heat transfer. This paper focuses on providing economical methods which are optimized and easily implementable solutions in the existing manufacturing setup. The above techniques are implemented on compressor head body. All possible attempts are made to change the cross section and the shape of the heat transfer areas so that maximized heat transfer reached in the operating process. The implementation of the optimize techniques is carried out by analyzing different cross sections such as straight, trapezoidal and parabolic. The scope of revising the strategies ultimately helps to increase productivity, efficiency, pointing to increase the profit. The only aim to propose the solution is to optimize the heat transfer rate by the change in the design Keywords: Heat Transfer, Fins, Compressor, Cross section, efficiency

Optimization of Heat Transfer Rate in Fins by CAE

Abstract: Overheating and excessive increase in the temperature of the compressors body causes thermal loading on the compressors surfaces. The life of the compressor mainly depends upon the abrupt change in the thermal stresses and the pressure stress induced in the body. The life of the compressor can be successfully improved and optimized by working on the compressor body. Specifically speaking the compressors fin areas is the heat affected area. Change in small cross section area can significantly change the convective heat transfer. This paper focuses on providing economical methods which are optimized and easily implementable solutions in the existing manufacturing setup. The above techniques are implemented on compressor head body. All possible attempts are made to change the cross section and the shape of the heat transfer areas so that maximized heat transfer reached in the operating process. The implementation of the optimize techniques is carried out by analysing different cross sections such as straight, trapezoidal and parabolic. The scope of revising the strategies ultimately helps to increase productivity, efficiency, pointing to increase the profit. The only aim to propose the solution is to optimize the heat transfer rate by the change in the design Keywords: Heat Transfer, Fins, Compressor, Cross section, efficiency

Simultaneous monitoring of vocal doses and breathing patterns in professional singers

BackgroundWhen learning and improving singing, the quantitative characterization of artists’ performances based only on vocal parameters does not provide enough information to identify strategies for improvement. Simultaneous monitoring of sound production and breathing patterns in professional singers can allow the exploration of the mechanisms that promote effective singing modalities through association with respiratory efforts. MethodsWe developed and tested a novel portable device that simultaneously monitors vocal activity and breathing patterns without interfering with natural singing. The device utilizes a combination of a miniature accelerometer to measure vocal doses from skin vibrations on the neck and two respiratory inductive plethysmography (RIP) bands to estimate the breathing pattern by measuring changes in the thoracoabdominal cross-sectional area. ResultsThe device was tested on 13 professional baroque-style singers and 14 untrained individuals during the execution of singing tasks. It was accurate compared with reference systems (R2 = 0.99 and R2 = 0.91 for the accelerometer and RIP, respectively) and showed differences between the two groups (p ≤ 0.001). Conclusions: By allowing a quantitative characterization of the effectiveness of singing technique, this novel device can help provide a better understanding of the physiology of singing and may be a tool for support learning and training optimization for professional singers.

Effects of resistance training intensity on muscle quantity/quality in middle-aged and older people: a randomized controlled trial.

BackgroundA sarcopenia diagnosis is confirmed by the presence of low muscle quantity or quality under the 2018 revised definition by the European Working Group on Sarcopenia in Older People 2. Imaging methods [i.e. magnetic resonance imaging (MRI)], dual‐energy X‐ray absorptiometry (DXA), and bioelectrical impedance analysis are tools to evaluate muscle quantity or quality. The present study aimed to investigate whether and how low‐intensity and moderate‐intensity resistance training improved both muscle quantity and quality measured by MRI, DXA, and segmental bioelectrical impedance spectroscopy (S‐BIS) in middle‐aged and older people.MethodsA single‐blind, randomized, controlled trial was conducted. Community‐dwelling people aged 50–79 years were randomly allocated to no exercise (no‐Ex), low‐intensity exercise (low‐Ex), and moderate‐intensity exercise (moderate‐Ex) groups. Participants in the exercise groups performed resistance training for 24 weeks, with loads of 40% and 60% of one repetition maximum in the low‐Ex and moderate‐Ex groups, respectively. Cross‐sectional area (CSA), lean mass, and muscle electrical properties on S‐BIS were used to determine the effects of training interventions on muscle quantity and quality of the lower limbs.ResultsFifty participants (no‐Ex 17, age 63.5 ± 8.5 years, women 47.1%; low‐Ex 16, age 63.6 ± 8.1 years, women 50.0%; moderate‐Ex 17, age 63.5 ± 8.3 years, women 52.9%) completed the 24 week exercise intervention. For the primary outcome, significant intervention effects were found in thigh muscle CSA on MRI between the moderate‐Ex and no‐Ex groups (+6.8 cm2, P < 0.01). Low‐Ex for 24 weeks only increased quadriceps CSA (+2.3 cm2, P < 0.05). The per cent change of thigh muscle CSA (+7.0%, P < 0.01) after 24 week moderate‐Ex was higher than that of leg lean mass on DXA (+2.3%, P = 0.088). Moderate‐Ex for 24 weeks also improved S‐BIS electrical properties related to muscle quantity and quality, including the intracellular resistance index (+0.1 cm2/Ω, P < 0.05), membrane capacitance (+0.7 nF, P < 0.05), and phase angle (+0.3 deg, P < 0.05); their changes were positively correlated with that of thigh muscle CSA (P < 0.01).ConclusionsResistance exercise with moderate intensity improved muscle quantity and quality measured by MRI and S‐BIS, whereas that with low intensity only increased muscle quantity in middle‐aged and older people. The comparisons among the responses to exercise between the assessment methods indicate the greater value of MRI and S‐BIS to measure changes of muscle quantity and quality than of lean mass measured by DXA for assessing the local effects of resistance training.

Sex-dependent jugular vein optical attenuation and distension during head-down tilt and lower body negative pressure.

Non‐contact coded hemodynamic imaging (CHI) is a novel wide‐field near‐infrared spectroscopy system which monitors blood volume by quantifying attenuation of light passing through the underlying vessels. This study tested the hypothesis that CHI‐based jugular venous attenuation (JVA) would be larger in men, and change in JVA would be greater in men compared to women during two fluid shift challenges. The association of JVA with ultrasound‐based cross‐sectional area (CSA) was also tested. Ten men and 10 women completed three levels of head‐down tilt (HDT) and four levels of lower body negative pressure (LBNP). Both JVA and CSA were increased by HDT and reduced by LBNP (all p < 0.001). Main effects of sex indicated that JVA was higher in men than women during both HDT (p = 0.003) and LBNP (p = 0.011). Interaction effects of sex and condition were observed for JVA during HDT (p = 0.005) and LBNP (p < 0.001). We observed moderate repeated‐measures correlations (r rm) between JVA and CSA in women during HDT (r rm = 0.57, p = 0.011) and in both men (rr m = 0.74, p < 0.001) and women (r rm = 0.66, p < 0.001) during LBNP. While median within‐person correlation coefficients indicated an even stronger association between JVA and CSA, this association became unreliable for small changes in CSA. As hypothesized, JVA was greater and changed more in men compared to women during both HDT and LBNP. CHI provides a non‐contact method of tracking large changes in internal jugular vein blood volume that occur with acute fluid shifts, but data should be interpreted in a sex‐dependent manner.

Long-Lasting Impairments in Quadriceps Mitochondrial Health, Muscle Size, and Phenotypic Composition Are Present After Non-invasive Anterior Cruciate Ligament Injury.

IntroductionDespite rigorous rehabilitation aimed at restoring muscle health, anterior cruciate ligament (ACL) injury is often hallmarked by significant long-term quadriceps muscle weakness. Derangements in mitochondrial function are a common feature of various atrophying conditions, yet it is unclear to what extent mitochondria are involved in the detrimental sequela of quadriceps dysfunction after ACL injury. Using a preclinical, non-invasive ACL injury rodent model, our objective was to explore the direct effect of an isolated ACL injury on mitochondrial function, muscle atrophy, and muscle phenotypic transitions.MethodsA total of 40 male and female, Long Evans rats (16-week-old) were exposed to non-invasive ACL injury, while 8 additional rats served as controls. Rats were euthanized at 3, 7, 14, 28, and 56 days after ACL injury, and vastus lateralis muscles were extracted to measure the mitochondrial respiratory control ratio (RCR; state 3 respiration/state 4 respiration), mitochondrial reactive oxygen species (ROS) production, fiber cross sectional area (CSA), and fiber phenotyping. Alterations in mitochondrial function and ROS production were detected using two-way (sex:group) analyses of variance. To determine if mitochondrial characteristics were related to fiber atrophy, individual linear mixed effect models were run by sex.ResultsMitochondria-derived ROS increased from days 7 to 56 after ACL injury (30–100%, P < 0.05), concomitant with a twofold reduction in RCR (P < 0.05). Post-injury, male rats displayed decreases in fiber CSA (days 7, 14, 56; P < 0.05), loss of IIa fibers (day 7; P < 0.05), and an increase in IIb fibers (day 7; P < 0.05), while females displayed no changes in CSA or phenotyping (P > 0.05). Males displayed a positive relationship between state 3 respiration and CSA at days 14 and 56 (P < 0.05), while females only displayed a similar trend at day 14 (P = 0.05).ConclusionLong-lasting impairments in quadriceps mitochondrial health are present after ACL injury and play a key role in the dysregulation of quadriceps muscle size and composition. Our preclinical data indicate that using mitoprotective therapies may be a potential therapeutic strategy to mitigate alterations in muscle size and characteristic after ACL injury.

Muscle Hypertrophy Is Affected by Volume Load Progression Models.

Nóbrega, SR, Scarpelli, MC, Barcelos, C, Chaves, TS, and Libardi, CA. Muscle hypertrophy is affected by volume load progression models. J Strength Cond Res 37(1): 62-67, 2023-This exploratory secondary data analysis compared the effects of a percentage of 1 repetition maximum (%1RM) and a repetition zone (RM Zone) progression model carried out to muscle failure on volume load progression (VLPro), muscle strength, and cross-sectional area (CSA). The sample comprised 24 untrained men separated in 2 groups: %1RM (n = 14) and RM Zone (n = 10). Muscle CSA and muscle strength (1RM) were assessed before and after 24 training sessions, and an analysis of covariance was used. Volume load progression and accumulated VL (VLAccu) were compared between groups. The relationships between VLProg, VLAccu, 1RM, and CSA increases were also investigated. A significance level of p ≤ 0.05 was adopted for all statistical procedures. Volume load progression was greater for RM Zone compared with %1RM (2.30 ± 0.58% per session vs. 1.01 ± 0.55% per session; p < 0.05). Significant relationships were found between 1RM and VLProg (p < 0.05) and CSA and VLProg (p < 0.05). No between-group differences were found for VLAccu (p > 0.05). Analysis of covariance revealed no between-group differences for 1RM absolute (p < 0.05) or relative changes (p < 0.05). However, post hoc testing revealed greater absolute and relative changes in CSA for the RM Zone group compared with the %1RM group (p < 0.001). In conclusion, RM Zone resulted in a greater VLPro rate and muscle CSA gains compared with %1RM, with no differences in VLAccu and muscle strength gains between progression models.

Pattern of changes in cross sectional area of arterial branches after jailing with pipeline embolization device: beyond parent neck artery patency

ObjectiveThe Pipeline-Embolization-Device (PED) has been used increasingly for intracranial-aneurysms. Despite the high-patency-rate of jailed branches following PED deployment, little is known about changes in these vessels size. This study measured change in size after PED. MethodsThis retrospective-study screened a database of 183-consecutive-patients treated with PED (07/2011-07/2017) across inclusion criteria. We included patients in whom the ophthalmic artery (OA) and/or the posterior communicating artery (PComA) were jailed by the PED. MRA was used to calculate change in cross-sectional-area (CSA) of these vessels. 29 patients who had MRA before and after treatment were included in the study. The CSA was measured automatically using Syngo®.via-software at fixed points along the analyzed vessels. After exclusion of low-quality and software non-capturable MRA-images, 16 OA and 23 PComA were included in the final analysis. Statistical Package for Social Sciences was used for analysis. ResultsThe mean CSA of PComA, P1-segement of posteriror-cerebral-artery (P1-PCA), and OA was 3.3 ± 1.3, 4.1 ± 1.2, and 3.2 ± 0.9 mm2 at baseline and 1.9 ± 1.4, 4.3 ± 1.2, and 3.1 ± 0.7 mm2 at follow-up, respectively. The average follow-up was approximately 26 months. While the decrease in CSA of PComA was statistically significant, the increase in P1-PCA CSA was not. The change in OA CSA was not statistically significant. ConclusionJailing PComA with a PED resulted in a statistically significant decrease in PComA CSA and a statistically non-significant increase in ipsilateral P1 CSA. No statistically significant change in the CSA of OA was noted. Changes might be due to a balance between flow demand through the jailed ostium and presence of collateral flow.

The detection of keratoconus using novel metrics derived by anterior segment optical coherence tomography.

To determine through a feasibility study whether anterior and posterior corneal arc length and cross-sectional area measured using anterior segment ocular coherence tomography (AS-OCT) can distinguish between healthy and keratoconic corneas. Patients diagnosed with keratoconus along with healthy controls underwent AS-OCT. ImageJ was used to determine the central 6mm anterior and posterior corneal arc lengths and cross-sectional areas. Each length and area was then divided into 1-mm segment and relative differences compared. Twenty-five eyes from 15 patients with keratoconus, along with 25 eyes from 14 healthy controls were enrolled. There was a statistically significant difference in anterior and posterior corneal arc lengths as well as corneal cross-sectional area (p = 0.006, p = 0.005, p = 0.01, respectively). When selecting for the less advanced keratoconus eye, it was noted that posterior corneal arc length was longer in the paracentral temporal segment (1003 vs. 1010µm, p = 0.04) and that greater change in corneal cross-sectional areas occurred between adjacent segments in less advanced keratoconus eyes. AS-OCT is capable of reliably measuring corneal arc lengths in patients with keratoconus and healthy patients. Both anterior and posterior corneal arc lengths along with central cross-sectional areas are statistically different between healthy and keratoconus eyes.

Functional improvements to 6months of physical activity are not related to changes in size or density of multiple lower-extremity muscles in mobility-limited older individuals.

Older adults are encouraged to engage in multicomponent physical activity, which includes aerobic and muscle-strengthening activities. The current work is an extension of the Vitality, Independence, and Vigor in the Elderly 2 (VIVE2) study - a 6-month multicenter, randomized, placebo-controlled trial of physical activity and nutritional supplementation in community dwelling 70-year-old seniors. Here, we examined whether the magnitude of changes in muscle size and quality differed between major lower-extremity muscle groups and related these changes to functional outcomes. We also examined whether daily vitamin-D-enriched protein supplementation could augment the response to structured physical activity. Forty-nine men and women (77±5yrs) performed brisk walking, muscle-strengthening exercises for the lower limbs, and balance training 3 times weekly for 6months. Participants were randomized to daily intake of a nutritional supplement (20g whey protein+800IU vitamin D), or a placebo. Muscle cross-sectional area (CSA) and radiological attenuation (RA) were assessed in 8 different muscle groups using single-slice CT scans of the hip, thigh, and calf at baseline and after the intervention. Walking speed and performance in the Short Physical Performance Battery (SPPB) were also measured. For both CSA and RA, there were muscle group × time interactions (P<0.01). Significant increases in CSA were observed in 2 of the 8 muscles studied, namely the knee extensors (1.9%) and the hip adductors (2.8%). For RA, increases were observed in 4 of 8 muscle groups, namely the hip flexors (1.1HU), hip adductors (0.9HU), knee extensors (1.2HU), and ankle dorsiflexors (0.8HU). No additive effect of nutritional supplementation was observed. While walking speed (13%) and SPPB performance (38%) improved markedly, multivariate analysis showed that these changes were not associated with the changes in muscle CSA and RA after the intervention. We conclude that this type of multicomponent physical activity program results in significant improvements in physical function despite relatively small changes in muscle size and quality of some, but not all, of the measured lower extremity muscles involved in locomotion.

THIGH MUSCLE CHANGES CAN WORSEN SUBSEQUENT KNEE OA CLINICAL OUTCOMES: USE OF DEEP LEARNING AND PROPENSITY-SCORE MATCHING ON OAI DATA

Thigh muscles play an important role in knee joint biomechanical stability, and changes in their size and quality are associated with knee OA incidence. There are currently no known disease-modifying medications for mitigating knee OA-related symptom worsening and delaying TKA. Therefore, non-surgical, non-pharmacological approaches targeting thigh muscle strengthening and composition have important clinical implications. The structural therapeutic effects of such interventions can be quantified using muscle MRI. However, no conclusive longitudinal data is available on the association of quantitative thigh muscle MRI markers with knee OA-related clinical outcomes. We aimed to investigate the longitudinal changes in quantitative muscle cross-sectional area (CSA) and adipose tissue in knee OA and their association with downstream symptom worsening and TKA. We trained, tested, and implemented a fully automated supervised deep learning model to segment longitudinal thigh MRIs of a large sample of the OAI participants. In an analysis of OAI data, knees of participants with available quality thigh MRIs at baseline and at least one follow-up visit were included and classified as with and without knee OA according to baseline radiographic KLG ≥2 and matched for confounders using propensity score matching. An automated deep learning model for thigh MRI 2D-segmentation was developed and tested. Markers of muscle CSA and intramuscular adipose tissue (intra-MAT) were measured at baseline, 2nd and 4th-years follow-up (period-1) and compared between knees with and without knee OA using linear mixed-effect regression models. Furthermore, in knees with knee OA, the association of period-1 changes in muscle markers with risk of TKA (Cox proportional-hazards) and symptom worsening (mixed-effect models) during the 4th- to 9th-year (period-2) was evaluated. This study included 4,634 matched-thighs (2,317:2,317 with:without knee OA) of 2,344 participants (mean age±SD:62±9, 1,292 females). Compared with those without, knees with knee OA had a decrease in quadriceps CSA (mean difference: -8.21mm2/year, p:.004) and an increase in quadriceps intra-MAT (1.98mm2/year, p:.007). Decreased CSA and increased intra-MAT of quadriceps during period-1 predicted downstream (period-2) knee OA symptom worsening (WOMAC total score, odds ratios:0.24 (negative association), p<.001, and 1.38, p:.019, respectively). Quadriceps CSA changes, negatively associated with higher future TKA risk (hazard ratio:0.70, p<.001). Knee osteoarthritis was associated with longitudinal MRI-derived decreased quadriceps cross-sectional area and increased intramuscular adipose tissue. These potentially modifiable risk factors predicted downstream symptom worsening and knee replacement. NIH NIA, Award Number P01AG066603 NIH NIAMS, Award Number R01AR079620-01 AG reported receiving funding from Merck Serono, AstraZeneca, Galapagos, Pfizer, Roche, TissueGene (for consultation), and Boston Imaging Core Lab (as the president and stockholder). SD reported that he received funding from Toshiba Medical Systems (for consultation) and grants from GERRAF and Carestream Health (for a clinical trial study). Authors acknowledge OAI staff and team. CORRESPONDENCE ADDRESS: Mohajer.bahram@gmail.com .

Failure analysis of PTO shaft of an agricultural tractor

The Power Take-Off (PTO) shaft is an efficient means of transferring mechanical power between farm tractors and attached implements. The PTO shaft of any agricultural tractor is basically a drive shaft engraving with number of splines that converts the primary energy of the tractor to a rotating motion of a nicely connected power shaft. The shaft is usually having external splines and its rotational movement is actually valuable for the operation of various farm implements like pumps, thresher, rotary tiller etc. to do numerous farming operations because it could be coupled at its external end. Because of the movement of the PTO shaft, the attached implements perform the final agricultural operations. During the operations, number of failures usually occurred to the PTO the shaft and the attached implements. They could become very unsafe to the users as it may stopped working of the attached implement/equipment suddenly. In this research, a metallurgical investigation has been carried out to study the root cause of failure in a PTO shaft. It was found out that the failure happened where there is sudden change in the shaft cross sectional area which leads its failure due to torsion and bending effects. The analysis results may be helpful to the end users as far as the cost during various farming operations is concerned.

Damage and Fracture Analysis under Multi-axial Stress State Based on Damage Mechanics

In various press forming and deep drawing processes, it is important to anticipate the forming limit in multi-axial stress state. In the uniaxial tension test, it is necessary to take stress triaxiality into account for accurate prediction of failure strain, because after the onset of the necking, the constricted portion, which is actually subjected to loading, is in the multiaxial stress state due to the change in local cross-sectional area. Recently, several damage and fracture models have been proposed that focus on the effect of stress triaxiality on the forming limit, while most of them are phenomenological models. In this study, the constitutive equation and damage evolution equation, which are based on a second-order symmetric damage tensor within the framework of the continuum damage mechanics, are constructed as a function of the stress triaxiality to analyze damage and fracture of materials in multiaxial stress state. Then, FEM analysis of an example problem was carried out to validate this material model.

Association between age and muscle function, architecture, and composition in long-distance master runners: a cross-sectional study.

The aim of this study was to describe the muscle function, architecture, and composition of long-distance master runners, and verify the association between age and these variables. Additionally, different clusters of runners were compared based on age and training variables. Forty male runners (≥50 years) reported their training routine and had their muscle function evaluated through maximum knee extensor isometric peak torque (PT) assessed with an isokinetic dynamometer. The cross-sectional area (CSA), pennation angle (PA), fascicle length (FL), muscle thickness (MT), and echo intensity (EI) were evaluated through ultrasound (muscle architecture and composition). The participants were 58.7±6.2 years old and had been training for 18.4±10.3 years, 4 sessions/week with 298.8±164.7 min/week of training. The absolute torque was 226.92±63.44 N·m, and the specific torque (PT/CSA) was 7.29±3.78 N·m/cm2. Regarding muscle architecture, the phase angle was 17.34±4°, the fascicle angle 6.78±1.04 cm, muscle thickness 2.93±0.56 cm, and the cross-sectional area 21.24±5.88 cm2. Concerning muscle composition, the master runners showed echo intensity values of 62.05±11.68 AU. The analysis demonstrated a weak and negative association between age and some muscle architecture variables (CSA and MT) and muscle function (PT). No association was verified between age and muscle composition (EI). Age partially explained CSA, MT, and muscle function changes (13, 11, and 14%, respectively). Participants' high level of physical training might have contributed to the low association between these variables and the lack of association with muscle composition.

Histomorphological and inflammatory changes of white adipose tissue in gastrointestinal cancer patients with and without cachexia.

BackgroundDuring cancer cachexia, several alterations occur in peripheral tissues, and the adipose tissue may be involved during the catabolic state. We aimed at investigating histological rearrangement and infiltration of inflammatory cells in subcutaneous adipose tissue (SAT) of patients with cancer undergoing surgery, according to the presence/absence of cachexia.MethodsWe considered gastrointestinal cancer patients and controls with non‐malignant diseases undergoing surgery. We collected SAT samples and performed histomorphological analyses [cross‐sectional area (CSA) and per cent of fibrosis] and immunohistochemistry to characterize the inflammatory cells. By computed tomography (CT) scan, we calculated SAT and visceral adipose tissue (VAT).ResultsWe enrolled 51 participants (31 gastrointestinal cancer patients and 20 controls). In cancer patients, cachexia was present in 13/31 (42%). The CSA (μm2) of the adipocytes from SAT was reduced in cancer patients vs. controls (3148, inter‐quartile range 2574–3755 vs. 4474, inter‐quartile range 3654–5183) (P < 0.001), in particular in cachectic patients vs. non‐cachectic (median 2518 vs. median 3470) (P = 0.03) and in cachectic vs. controls (P < 0.001), as well as in non‐cachectic vs. controls (P = 0.04). The median per cent of fibrosis was higher in cancer patients vs. controls (9 vs. 3) (P = 0.0001), in particular in cachectic vs. non‐cachectic (13.35 vs. 7.13) (P = 0.03). We observed a higher number of macrophages (CD68) (P = 0.0001) and T lymphocytes (CD3) (P = 0.002) in SAT of cancer patients vs. controls, and the number of T lymphocytes was higher in cachectic vs. non‐cachectic patients (P = 0.025). Anorexic cancer patients showed in SAT a higher number of macrophages and T lymphocytes with respect to controls (P < 0.0001), whereas no difference was present between anorexic and non‐anorexic patients. At CT scan, cachectic patients showed lower VAT and SAT vs. non‐cachectic (VAT: 97.64 ± 40.79 vs. 212.53 ± 79.24, P = 0.0002; SAT: 126.27 ± 87.92 vs. 206.27 ± 61.93, P = 0.01, respectively). Cancer patients with low CSA, high degree of fibrosis, and high number of T lymphocytes presented with lower body mass index and lower SAT and VAT at CT scan (P ≤ 0.01).ConclusionsWe found histological alterations of SAT among gastrointestinal cancer patients and in particular significant changes in CSA, fibrosis, and inflammation when cachexia was present; the changes in histomorphological parameters of the adipocytes reflected alterations in adiposity at body composition analysis.

The Study of Cerebral Blood Flow Variations during Brain Metastases Radiotherapy

Purpose: The aim of this study was to investigate the cerebral blood flow (CBF) variations during brain metastases (BMs) radiotherapy (RT) applying with magnetic resonance (MR) 3D-arterial spin labeling (ASL). Materials and Methods: A total of 26 BM patients with 54 tumors were retrospectively enrolled. MR examinations were performed before and during RT (30–50 Gy) with a total dose of 36–60 Gy (12–30 fractions) including contrast-enhanced T1-weighted, T2 Flair, and 3D-ASL images. The relationship between CBF changes and the largest cross-sectional area changes in BMs was investigated. And CBF changes in BMs, normal brain tissue, and peritumoral edema areas were analyzed under different dose gradients that were divided into 10 Gy intervals. Results: The largest cross-sectional areas and CBF of 54 BMs decreased by 26.46% and 29.64%, respectively, during RT (p < 0.05), but there was no correlation between the 2 changes (p > 0.05). The rates of CBF decrease in BMs were 33.75%, 24.61%, and 27.55% at 30–40, 40–50, and >50 Gy, respectively (p < 0.05). In normal brain tissue with dose gradients of 0–10, 10–20, 20–30, 30–40, 40–50, and >50 Gy, the CBF decreased by 7.65%, 11.12%, 18.42%, 20.23%, 19.79%, and 17.89%, respectively (p < 0.05). The CBF decreases reached a maximum at 30–40 Gy in normal brain tissue as well as BMs. In contrast, the CBF decreases of peritumoral edema areas increased as the dose gradients increased. Moreover, the CBF changes of BMs were more notable than those in normal brain tissue and peritumoral edema areas. Conclusion: CBF changes can be feasibly assessed in different brain regions during RT based on 3D-ASL. The changes should be considered as a critical factor to determine the personal radiation dose for BMs, normal brain tissue, and peritumoral edema areas.