Adjustment For Height Research Articles

Analyze the physical interaction between the user and the furniture design to optimize comfort and functionality

The physical interaction between users and furniture is pivotal in determining comfort and functionality, particularly in environments where individuals spend extended periods, such as offices, homes, and public spaces. This study aims to analyze how different furniture designs impact user comfort, postural stability, and long-term usability. By employing a hybrid research framework combining observational studies, simulations, and advanced technological tools such as motion tracking, pressure mapping, and biomechanical sensors, the research provides a comprehensive evaluation of user-furniture interaction. The study involved 178 participants with diverse demographic backgrounds, allowing for a broad range of body types, ages, and activity levels to be examined. Key findings indicate that ergonomic features such as adjustable seat height, lumbar support, and reclining mechanisms significantly enhance comfort, particularly when customized to the user’s anthropometric profile. For example, adjustable seat height reduced pressure on the thighs, improving comfort by 8.5% over prolonged periods. Additionally, lumbar support was the most compelling feature in alleviating muscle strain, improving overall comfort by 9.0%. The analysis of long-term comfort revealed that postures supporting dynamic movements, such as using a standing desk, maintained higher comfort levels over time compared to static postures like leaning forward, which showed a marked increase in muscle fatigue. Postural stability analysis showed that sitting at a 90° angle provided the best balance of stability and long-term comfort, with a usability rating 8.4. In contrast, leaning forward exhibited the lowest postural stability and the highest discomfort, making it unsuitable for prolonged tasks.

Muscle Mass and Muscle Strength in Non-Dialysis-Dependent Chronic Kidney Disease Patients.

Background: Sarcopenia is a state with a progressive and generalized loss of skeletal muscle mass and strength. However, muscle strength and muscle mass are different features, which are usually not studied separately. The aim of the study was to investigate anthropometric and clinical correlates and sources of variation in both skeletal muscle mass and muscle strength in chronic kidney disease (CKD). Methods: The study sample consisted of 84 patients with an estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m2. Muscle strength was estimated by measuring hand grip strength (HGS). Muscle quantity was measured with bioimpedance spectroscopy (BIS). Serum creatinine, urea, uric acid (UA), and albumin were measured as well. Results: Appendicular skeletal muscle mass (ASM) significantly and positively correlated with body mass, NH weight (normally hydrated weight), height, body mass index (BMI), lean tissue mass (LTM), lean tissue index (LTI), fat mass (FM), and fat tissue index (FTI), and was negatively associated with hydration status. HGS significantly and positively correlated with body mass, NH weight, height, LTM, LTI, and ASM, and was negatively associated with UA and urea. After adjustment for age, sex, and height, HGS remained significantly and negatively related with UA and hydration status. Conclusions: In CKD patients, ASM is determined by anthropometric parameters, but HGS is determined by both anthropometric and clinical variables specific for CKD. In order to study the determinants of HGS in CKD, relationships with HGS should be adjusted for anthropometric variables.

Aortic dimensions in a large Australian adult cohort. New normal range?

Abstract Background There is little published data worldwide about the normal range of aortic dimensions in adults. Guidelines for dilated aortic dimensions and recommendations for surgery are based on small population cohorts and absolute values. Adjustment for BSA and height are becoming more accepted, however the normal range of aortic dimensions for a large population has not been previously published. We present the distribution of aortic dimensions in a large Australian population, with indexation for BSA and height as well as centiles of age. Methods All patients &amp;gt;18 years of age attending for routine echocardiography at our institution from 2007-2022 were included in the database. Measurements of aortic root, sinotubular junction and ascending aorta using ASE criteria were collated. Dimensions were adjusted for BSA and height. Data was analysed for centiles of weight and height and across decades of age. Results A total of 117,912 patients were included in the analysis, aged 62.8+17.6 years (range 18-107), 59% male, 83.7+21.1 kgs (range 32-337) and 169.8+10.3 cm (range 107-218). The aortic root and ascending aortic dimensions are presented in absolute values (average + SD), and height adjusted (cm/m) and BSA adjusted (cm/m2) values. Data was expressed per centile of height, age and weight. There was a progressive increase in aortic dimensions as expected for increasing height, however a robust relationship was identified when dimensions were indexed according to height at all centiles regardless of age and body weight. In contrast, when adjusted for BSA, the aortic dimensions were progressively and predictably under-reported in patients over 80kg for assessment for normal vs dilated. When analysed for centiles of age, there was a small progressive increase in dimensions observed with increasing age. The indexation for height was independently robust across patients of all centiles of height. Conclusion Aortic dimensions are consistently 2.0+0.5 cm/m when adjusted for patient height across all body weight and age centiles. Adjustment for BSA in patients over 80kg tends to under-represent aortic dimensions when assessing for dilatation. Dimensions tend to increase gently with increasing age. We propose a new nomogram for normal aortic dimensions in adults.

Vehicle height control of air suspension based on speed adaptive double-zone model prediction

The electronically controlled air suspension (ECAS) system improves the ride comfort and stability of the vehicle by adjusting the vehicle height. Due to the compressibility of air and the inertia of suspension, the ECAS system has the problem of excessive adjustment in the process of vehicle height adjustment, so that the solenoid valve is repeatedly opened and closed. Aiming at this problem, this paper proposes a new vehicle height control method based on speed adaptive double-zone model prediction control (AD-MPC), which realizes the adjustment of vehicle height with less operation of solenoid valve. Firstly, the single-wheeled air suspension is selected as the characteristic model and the spatial state equation is established. Then, the seeker optimization algorithm for the double-zone selection problem is designed to quickly find the best double-zone to obtain a double-zone function that can adapt to the speed. And then, the predictive control method based on AD-MPC is designed. Finally, the effectiveness and feasibility of the method are verified by simulation and experiment.

5120 Contribution Of Proximal Femur Geometry And Bone Density Distribution To Hip Fragility In Adults ≥ 50yrs With Longstanding Type 1 Diabetes

Abstract Disclosure: F. Johannesdottir: None. C. D’Mello: None. A.B. Murthy: None. B. Zahedi: None. K. Engelke: None. M.L. Bouxsein: None. E.W. Yu: Grant Recipient; Self; Amgen Inc. Introduction: Adults with type 1 diabetes (T1D) have a 6-fold increased risk of hip fracture, which is explained only in part by lower areal bone mineral density (aBMD) by DXA. We hypothesize that femoral geometry and regional bone deficits at the proximal femur contribute to higher hip fracture risk in older adults with T1D. Further, we determine the influence of age at T1D diagnosis on femoral bone density and structure. Methods: We enrolled 97 individuals with T1D and 53 non-diabetic controls (CON) as part of the T1D Bone Health Connection (BEACON) Study, an ongoing prospective study of adults aged ≥50 years. We obtained computed tomography (CT) scans of the proximal femur (in-plane pixel size 0.98x0.98 mm, 1.25 mm slice thickness) to measure total (Tt), trabecular (Tb) and cortical (Ct) volumetric BMD (vBMD); and volume (Vol) and Ct thickness (Th) in several regions, including total hip, femoral neck (FN), trochanter (TR) and intertrochanter (IT) (Medical Image Analysis Framework, University of Erlangen, Germany). We also assessed total hip and FN aBMD by DXA. We employed ANCOVA models to compare bone outcomes between T1D and controls with adjustment for age, height, and weight, stratified by sex. When comparing bone outcomes within T1D, we adjusted for age, height, weight, and sex. Differences are reported as % difference between the least-square means for the groups. Results: The average age of participants was 64±7 yrs, and similar between T1D and CON (p=0.21). Male T1D were shorter than male CON (173 cm vs 176 cm, p=0.05), but with similar weight (p=0.73). Female T1D were heavier than female CON (71 kg vs 64 kg, p=0.03). The T1D cohort included 50 men and 47 women with mean diabetes duration of 46±10 yrs, mean A1c 7.1±1.0%, and median age at onset 17 yrs (IQR:10-25). Among T1D, 31 (52% female) were diagnosed ≤ age 12. Among men, total hip and FN aBMD did not differ by group, but T1D had smaller FN Tt.Vol (9%) and FN width (8%) (p&amp;lt;0.05 for all). In contrast, there were no differences between T1D and CON in the female cohort, neither by DXA nor CT (p≥0.13). Of note, T1D men appeared to have more poorly controlled diabetes than women (29% of men vs 11% women had A1c ≥8%, p=0.03). Within T1D, those who were diagnosed ≤ age 12 had lower Tb.vBMD (16-18%) at the total hip, TR and IT regions (p&amp;lt;0.05) and tended to have lower Tb.vBMD (16%, p=0.06) at the neck compared to those diagnosed at a later age, but no differences in DXA aBMD (p&amp;gt;0.31). Conclusion: In sum, older men, but not women, with T1D showed some deficits in bone structure at the proximal femur. Adults with T1D who were diagnosed ≤ age 12 had trabecular bone deficits within the proximal femur. Additional studies are needed to identify mechanisms underlying the high hip fracture risk in T1D. Presentation: 6/1/2024

6825 α-Klotho Levels in Girls with Central Precocious Puberty

Abstract Disclosure: I. Hwang: None. E. Kim: None. Background: The exact mechanisms that trigger the onset of puberty are not fully understood. While it is known that elevated estradiol during puberty induces an increase in IGF-1, which subsequently promotes a rise in α-klotho levels, the relevance of these elevated α-klotho levels in children with Central Precocious Puberty (CPP) remains to be established. Given the potential significance of α-klotho in pubertal development, we initiated this study to determine whether increased α-klotho levels in CPP children are meaningfully pronounced and if these levels could serve as a reliable marker for CPP diagnosis and monitoring. Methods: A total of 139 girls were enrolled in the study, comprised of 82 diagnosed with CPP and 57 who were healthy prepubertal controls. From March 2020 to May 2023, we assessed both α-klotho levels and clinical parameters. α-klotho concentrations were measured using an α-klotho ELISA kit. For the girls with CPP, we additionally analyzed samples taken 6 months after GnRH agonist treatment. Result: α-Klotho levels were higher in the CPP group compared with the controls (CPP group: 2529 ± 999 ng/mL; control group: 1802 ± 675 pg/mL) (P &amp;lt; 0.001). α-Klotho significantly decreased after 6 months on GnRH agonist treatment.(2147± 789 pg/mL) (P &amp;lt; 0.001). α-Klotho levels were positively correlated with height-SDS, weight-SDS, bone age, ALP, IGF-1 SDS, baseline FSH and LH. α-Klotho relationship with IGF-1 SDS, baseline LH studied by partial correlation with adjustment for age, height and weight SDS (r= 0.275, p= 0.003; r= -0.229, p= 0.014). A ROC curve analysis identified an α-klotho cut-off differentiating CPP from controls, with a cut-off of 1914 pg/mL distinguishing CPP girls from controls with a sensitivity of 69.5% and specificity of 70.2%; the area under the curve was 0.723. Conclusion: Our study indicates a notable association between elevated α-klotho levels and CPP, especially as these levels adjust following GnRH agonist treatment. Based on our findings, considering α-klotho concentrations might offer a way to distinguish CPP from controls. Further studies could elucidate the potential of α-klotho as a biomarker for CPP diagnosis and monitoring. Presentation: 6/1/2024

Physical and numerical tests on adjustable–height structures of high–speed railway transition section

The disparity in stiffness and differential settlement between the subgrade and rigid structures can lead to track irregularities within transition sections, resulting in significant train vibrations and impacts. This study proposes an adjustable–height subgrade structure for transition sections by introducing a raft slab to divide the subgrade into upper and lower parts. When settlement occurs in the subgrade, the raft slab can be elevated using height–adjustment techniques to compensate for the settlement. To this end, large–scale physical model tests are conducted under train loading to verify the design's rationality and to elucidate the influence of settlement magnitude and train speed on the stress and deformation of the slab. The experimental results indicate that the maximum principal stress and maximum shear stress of the slab generally increase with settlement magnitude and train speed, and the area near the abutment end is the most unfavorable position for the deformation of the slab. However, it is still lower than the design compressive strength of the C40 concrete structure. Thus, the designed adjustable–height structure meets the load–bearing requirements under train loading. Additionally, a numerical simulation model of the adjustable–height structure is developed to investigate the recovery capabilities and stress distribution of the settled raft slab. The results indicated that whether the lifting operation employed linear load or equal load methods, the raft slab primarily endured compressive stress, and there is stress concentration at the lifting points. For the same lifting displacement, the linear load method proved to be more reasonable than the equal load method. These findings have significant practical and theoretical implications for ensuring the safe and smooth operation of high–speed railways, effectively addressing the post–construction settlement deformation control challenges in ballastless track transition sections.

Drop Test Simulation of Packaging for Dangerous Goods: An Investigation of Appropriate Drop Height Adjustment in Case of Deviating Packaging Gross Mass

ABSTRACTIn the approval process of dangerous goods packagings, drop tests onto a flat, essentially unyielding surface are used to assess resistance against mechanical damage. International adopted regulations like ADR and RID define filling good dependent drop heights and filling degrees whilst the user needs to define the maximum gross mass to be tested and approved. Maximum packaging gross mass is defined conservatively and not reached in practice. To meet the defined gross mass in testing, using additives is permitted. However, in some cases, additives are not desirable due to packaging design or filling substance properties. This leads to deviations from the initial gross mass definition. Hence, a certain drop height adjustment is necessary to achieve the required impact loading. Laboratories frequently adjust drop height assuming a perfectly elastic collision that is inaccurate. Appropriate adjustment is not trivial due to energy conversion processes, for example, plastic deformation. In this work, a test stand is developed for measuring the change in kinetic energy of different packaging designs and filling substances in regulative drop tests. The experimental results are used to validate finite‐element (FE) models so that packaging properties can be varied in simulated drop test scenarios. The findings intend to describe the appropriate drop height adjustment of the respective packaging with same design but deviating gross mass to produce comparable mechanical response. The results are highly beneficial for testing laboratories, approval issuing authorities and packaging institutes confronted with the problem of testing packages with gross masses other than those to be approved.

Investigation of Impact Contact Force Testing and Damage Analysis on Potatoes

To investigate the influencing factors and intrinsic relationships between potato impact force and impact damage during potato soil separation, a testing system for potato impact force was established. The impact force test system is composed of a base, a height adjustment device, a simple separation screen, a soil storage tank, an impact force sensor, and so on. By allowing potatoes to fall freely to simulate the collision process, impact force data are collected, and a high-speed camera is used to locate the impact position and analyze the degree of damage. Through the response surface analysis method, the influencing factors and laws of the impact force and impact damage during the collision process between potatoes and rods under soil and no-soil conditions were studied. The results of the response surface analysis indicate that when the screen inclination is within the range of 14.12° to 14.77°, falling height ranges from 453.83 mm to 500 mm, screen rod spacing falls within 36.50 mm to 40 mm, and the screen rod material is rubber. Potatoes can still be at a relatively low damage level when enduring a large impact force. This study has significant implications for reducing potato impact damage during harvesting, enhancing economic benefits in the potato industry, and advancing the technical level of potato harvesting equipment. In the future, based on the results of this study, further exploration can be made to optimize the design of potato harvesting equipment so as to better reduce the damage to potatoes during harvesting and subsequent processing processes and promote the sustainable development of the potato industry.

Heel Riser Height Influence on Kinematics and Muscle Activity of Ski Mountaineering: A FieldBased Study

Introduction: The ski binding plays an important role in ski mountaineering. When traveling uphill, the binding has an adjustable heel height known as the riser. Previous laboratory research reported joint kinematics and kinetics are influenced by riser height, however little is known about changes to muscle activity associated with differing joint motion. The purpose of this work was to assess riser height influence on kinematics and muscle activity at different slopes during on-snow skiing. Methods: Three female and nine male recreational ski mountaineers (19-26 y) were tested on 5o and 16o gradients using no riser (0 cm) and riser (5.3 cm) at a submaximal 80% HRmax. Each subject used Backland 85 UL skis and Backland Bindings (Atomic Skis, Altenmarkt, Austria). Subjects skied for 6 min at each binding setting with the last 10 gait-cycles evaluating lower limb joint motion gathered from 2D-sagittal plane motion capture. Electromyography (EMG) collected unilaterally on the rectus femoris, biceps femoris, medial gastrocnemius and triceps brachii also. Results: 5o slope: hip range of motion [ROM] decreased (p = .003), ankle ROM decreased (p =.005), stride length decreased (p = .004), RPE increased (p = .02) for riser compared to no riser. At 16o slope: hip ROM decreased (p = .001), and Rating of perceived exertion [RPE] decreased (p =.004) for riser compared to no riser. HR, glide distance, velocity, EMG, and net mechanical efficiency were not different between riser heights on either slope. Conclusion: Lower body joint kinematics, step length and RPE varied significantly with riser height. Kinematic differences did not impact velocity or muscle activity when controlling pace. These results agree with previous findings showing minimal differences in EMG and HR while lower body kinematics and RPE changed with riser height.

Bone Accrual Trajectories in Children and Adolescents with Perinatal HIV Infection.

Low bone mineral density (BMD) has been reported in children and adolescents living with perinatally-acquired HIV (PHIV). Little is known about their bone accrual through puberty compared to an uninfected healthy cohort. To compare bone accrual in PHIV and healthy children. PHIV children aged 7-16 years had dual energy X-ray absorptiometry (DXA) at entry, 2 years, and then at least 2 years later. Bone accrual was compared to healthy children from the Bone Mineral Density in Childhood Study (BMDCS). United States academic clinical research centers. 172 PHIV; 1321 BMDCS. We calculated height-adjusted whole-body and spine BMD and bone mineral content (BMC) Z-scores in PHIV using BMDCS reference curves. We fit piecewise weighted linear mixed effects models with change points at 11 and 15 years, adjusted for age, sex, race, height Z-score, and Tanner stage, to compare BMD and BMC Z-scores across actual age by cohort.Main Outcome Measure: BMD/BMC Z-scores. Height-adjusted whole-body BMD and BMC Z-scores in PHIV were lower across age compared to BMDCS children. Spine BMD Z-score across age was higher in PHIV after height adjustment. Whole-body and spine bone area tended to be lower in PHIV. PHIV had slower accrual in whole-body and spine bone area before 14 years. After 15 years, bone area accruals were similar, as were height-adjusted spine BMC Z-scores, across age. PHIV had persistent deficits in all measures except height-adjusted spine BMD and BMC Z-scores. Data are needed on PHIV followed to adulthood.

Relative muscle indices and healthy reference values for sarcopenia assessment using T10 through L5 computed tomography skeletal muscle area

Sarcopenia is the age-related loss of skeletal muscle mass and function. Computed tomography (CT) assessments of sarcopenia utilize measurements of skeletal muscle cross-sectional area (SMA), radiation attenuation (SMRA), and intramuscular adipose tissue (IMAT). Unadjusted SMA is strongly correlated with both height and body mass index (BMI); therefore, SMA must be adjusted for body size to assess sarcopenic low muscle mass fairly in individuals of different heights and BMI. SMA/height (rather than SMA/height2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMA/height^2$$\\end{document}) provides optimal height adjustment, and vertebra-specific relative muscle index (RMI) equations optimally adjust for both height and BMI. Since L3 measurement is not available in all CT scans, sarcopenic low muscle mass may be assessed using other levels. Both a mid-vertebral slice and an inferior slice have been used to define ‘L3 SMA’, but the effect of vertebral slice location on SMA measurements is unexplored. Healthy reference values for skeletal muscle measures at mid- and inferior vertebra slices between T10 and L5, have not yet been reported. We extracted T10 through L5 SMA, SMRA, and IMAT at a mid-vertebral and inferior slice using non-contrast-enhanced CT scans from healthy, adult kidney donor candidates between age 18 and 73. We compared paired differences in SMA between the mid-vertebral slice versus the inferior slice. We calculated the skeletal muscle gauge as SMGHT=SMRA∗SMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMG_{HT}=SMRA*SMI_{HT}$$\\end{document}. We used allometric analysis to find the optimal height scaling power for SMA. To enable comparisons with other published reference cohorts, we computed two height-adjusted measures; SMIHT=SMA/height\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT}=SMA/height$$\\end{document} (optimal) and SMIHT2=SMA/height2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT2}=SMA/height^2$$\\end{document} (traditional). Using the young, healthy reference cohort, we utilized multiple linear regression to calculate relative muscle index z-scores (RMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT}$$\\end{document}, RMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT2}$$\\end{document}), which adjust for both height and BMI, at each vertebra level. We assessed Pearson correlations of each muscle area measure versus age, height, weight, and BMI separately by sex and vertebra number. We assessed the differences in means between age 18–40 versus 20–40 as the healthy, young adult reference group. We reported means, standard deviations, and sarcopenia cutpoints (mean-2SD and 5th percentile) by sex and age group for all measures. Sex-specific allometric analysis showed that height to the power of one was the optimal adjustment for SMA in both men and women at all vertebra levels. Differences between mid-vertebra and inferior slice SMA were statistically significant at each vertebra level, except for T10 in men. SMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT}$$\\end{document} was uncorrelated with height, whereas SMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT2}$$\\end{document} was negatively correlated with height at all vertebra levels. Both SMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT}$$\\end{document} and SMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT2}$$\\end{document} were positively correlated with BMI at all vertebra levels. RMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT}$$\\end{document} was uncorrelated with BMI, weight, and height (minimal positive correlation in women at L3inf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L3}_{inf}$$\\end{document}, L4mid\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L4}_{mid}$$\\end{document}, and L5inf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L5}_{inf}$$\\end{document}) whereas RMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT2}$$\\end{document} was uncorrelated with BMI, but negatively correlated with height and weight at all levels. There were no significant differences in SMA between 18–40 versus 20–40 age groups. Healthy reference values and sarcopenic cutpoints are reported stratified by sex, vertebra level, and age group for each measure. Height to the power of one (SMA/height) is the optimal height adjustment factor for SMA at all levels between T10mid\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {T10}_{mid}$$\\end{document} through L5inf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L5}_{inf}$$\\end{document}. The use of SMA/height2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMA/height^2$$\\end{document} should be discontinued as it retains a significant negative correlation with height and is therefore biased towards identifying sarcopenia in taller individuals. Measurement of SMA at a mid-vertebral slice is significantly different from measurement of SMA at an inferior aspect slice. Reference values should be used for the appropriate slice. We report sarcopenic healthy reference values for skeletal muscle measures at the mid-vertebral and inferior aspect slice for T10 through L5 vertebra levels. Relative muscle index (RMI) equations developed here minimize correlation with both height and BMI, producing unbiased assessments of relative muscle mass across the full range of body sizes. We recommend the use of these RMI equations in other cohorts.

Association of nighttime sleep duration at 1.5 years with height at 3 years: The Japan Environment and Children's Study.

Adequate nighttime sleep duration has been considered beneficial for linear growth in children; however, there is limited and conflicting evidence regarding the association between sleep duration and subsequent linear growth. To investigate the association between sleep duration at 1.5 years and height at 3 years of age. The Japan Environment and Children's Study is a nationwide prospective birth cohort study. Data from 52,140 term singleton births born at an appropriate-for-gestational age without background disorders that could potentially affect linear growth in the analyses were included. Nighttime and total sleep durations were calculated based on a self-administered questionnaire completed by caregivers. Tall stature was defined as height at or above the 75th percentile among participants. After adjustment for height at 1.5 years, sex, monthly age, mother's height, presence of siblings at 1.5 years, environmental tobacco smoke at 1.5 years, daily TV/DVD screen time at 2 years, attendance at nursery at 2 years, household annual income at birth, and parents' educational status, multivariate odds ratio (95% confidence interval) for tall stature at 3 years were 1.09 (1.01-1.17), 1.09 (1.01-1.17), and 1.25 (1.14-1.37) for 9.5 or 10, 10.5 or 11, and ≥ 11.5 h of nighttime sleep duration at 1.5 years, respectively, compared with those with ≤ 9 h sleep (p for trend <0.0001). Total sleep duration was not associated with tall stature. This study underscores the importance of nighttime sleep duration, not total sleep duration, in the linear growth of very young children.

Research on identification method of coal-rock interface based on ground penetrating radar in the driving face of soft coal seam

Coal–rock interface recognition is one of the key challenges in advancing unmanned rapid tunneling systems. To address this, a method based on variations in ground-penetrating radar (GPR) reflection wave amplitude is proposed for identifying coal-rock interfaces in soft coal seams. A mathematical model derived from Maxwell's equations calculates the coal seam area based on the reflected wave amplitude. Experiments using a 400 MHz radar antenna show that the method achieves identification errors of 3.58 cm, 3.74 cm, and 4.23 cm for coal-to-rock ratios of 1:2, 1:1, and 2:1, respectively. In practical applications within a coal mine excavation face, the identification error is 6.64 cm. This method provides crucial data for drum height adjustment and cutting arm speed regulation in unmanned tunneling systems.

The Construction and Application of a Digital Coal Seam for Shearer Autonomous Navigation Cutting.

Accurately obtaining the geological characteristic digital model of a coal seam and surrounding rock in front of a fully mechanized mining face is one of the key technologies for automatic and continuous coal mining operation to realize an intelligent unmanned working face. The research on how to establish accurate and reliable coal seam digital models is a hot topic and technical bottleneck in the field of intelligent coal mining. This paper puts forward a construction method and dynamic update mechanism for a digital model of coal seam autonomous cutting by a coal mining machine, and verifies its effectiveness in experiments. Based on the interpolation model of drilling data, a fine coal seam digital model was established according to the results of geological statistical inversion, which overcomes the shortcomings of an insufficient lateral resolution of lithology and physical properties in a traditional geological model and can accurately depict the distribution trend of coal seams. By utilizing the numerical derivation of surrounding rock mining and geological SLAM advanced exploration, the coal seam digital model was modified to achieve a dynamic updating and optimization of the model, providing an accurate geological information guarantee for intelligent unmanned coal mining. Based on the model, it is possible to obtain the boundary and inclination information of the coal seam profile, and provide strategies for adjusting the height of the coal mining machine drum at the current position, achieving precise control of the automatic height adjustment of the coal mining machine.

Sex and Size Disparities in Access to Liver Transplant for Patients With Hepatocellular Carcinoma.

Women on the liver transplant waiting list are less likely to undergo a transplant than men. Recent approaches to resolving this disparity have involved adjustments to Model for End-Stage Liver Disease (MELD) scoring, but this will not affect candidates who rely on exception scores rather than calculated MELD score, the majority of whom have hepatocellular carcinoma (HCC). To evaluate the association between female sex, candidate size, and access to liver transplant among wait-listed patients with HCC. This retrospective cohort study used US transplant registry data of all adult (aged ≥18 years) wait-listed liver transplant candidates receiving an HCC exception score between January 1, 2010, and March 2, 2023. Wait-listed liver transplant candidate sex. The association of female sex with (1) deceased-donor liver transplant (DDLT) and (2) death or waiting list removal for health deterioration were estimated using multivariable competing-risks regression. Results with and without adjustment for candidate height and weight (mediators of the sex disparity) were compared. The cohort included 31 725 candidates with HCC (mean [SD] age at receipt of exception, 61.2 [7.1] years; 76.3% men). Compared with men, women had a lower 1-year cumulative incidence of DDLT (50.8% vs 54.0%; P < .001) and a higher 1-year cumulative incidence of death or delisting for health deterioration (16.2% vs 15.0%; P = .002). After adjustment, without accounting for size, women had a lower incidence of DDLT (subdistribution hazard ratio [SHR], 0.92; 95% CI, 0.89-0.95) and higher incidence of death or delisting (SHR, 1.06; 95% CI, 1.00-1.13) compared with men. When adjusting for candidate height and weight, there was no association of female sex with incidence of DDLT or death or delisting. However, at a height cutoff of 166 cm, short women compared with short men were still less likely to undergo a transplant (SHR, 0.93; 95% CI, 0.88-0.99). In this study, women with HCC were less likely to receive a DDLT and more likely to die while wait-listed than men with HCC; these differences were largely (but not entirely) explained by sex-based differences in candidate size. For candidates listed with exception scores, additional changes to allocation policy are needed to resolve the sex disparity, including solutions to improve access to size-matched donor livers for smaller candidates.

Design and Testing of a 2-DOF Adaptive Profiling Header for Forage Harvesters

The existing forage harvester header cannot automatically adjust the height and inclination during operation, resulting in uneven stubble height of forage, which, in turn, affects the efficiency of harvesting and the quality of forage regeneration. To address this issue, this study conducted the design and experimentation of a 2-degrees-of-freedom (DOF) profiling header. Firstly, this study designed an adaptive profiling header with 2-DOF adjustment, which was realized by the height adjustment mechanism and the tilt angle adjustment mechanism. The relationship model between the profiling device and the attitude of the header was established so that the header can acquire ground undulation in real time through the angle sensor of the profiling device. In order to verify the rationality of the header design, a co-simulation model of ADAMS and MATLAB/Simulink was built, and the header attitude control system was designed based on the fuzzy PID algorithm. The co-simulation results show that the header height (H) is always kept around 150 mm during the forwarding process of the harvester, with a maximum error of 5.8 mm, and the average relative error (REH) and root mean square error (RMSEH) were 1.4% and 2.6 mm, respectively, and the maximum error of the tilt angle (γ) of the header is 0.53° and the RMSEγ is 0.22°, which indicates that the header profiling mechanism can accurately reflect the undulation of the terrain and the header attitude control system has good robustness. Finally, the test platform was built and tested in a grassland. The test results show that the average height of the header is 149.8 mm, the maximum error is 7.5 mm, and the REH and RMSEH are 3.4% and 5.3 mm, respectively. The average error of the header inclination is 0.34°, and the maximum error is 0.57°. The test results indicate that the header can realize the adaptive adjustment of height and inclination, and the control system has high precision, stability and reliability, meeting the demand of automatic regulation of header attitude of a forage harvester.

Shaping the skeleton: impact of GnRH analogue and sex hormone therapy on skeletal dimensions in transgender individuals.

Skeletal dimensions vary between sexes. Men typically have broader shoulders and women a wider pelvis. If gender affirming hormone therapy (GAHT) with or without prior puberty suppression (PS) alters these dimensions in transgender individuals remains unclear. To investigate impact of PS and GAHT on skeletal dimensions. Retrospective cross-sectional study. Gender identity clinic. Transgender individuals assigned male at birth (AMAB) and assigned female at birth (AFAB) who underwent dual-energy X-ray absorptiometry (DXA) scanning between ages 18 and 28 years were divided into four groups: Early PS (Tanner G/B2-3)+GAHT, Late PS (Tanner G/B4-5)+GAHT, GAHT only, and Untreated. Shoulder and pelvis dimensions measured by DXA scan were compared between groups, with adjustment for height. A total of 121 individuals AMAB and 122 AFAB were included. Only in individuals AMAB who underwent early PS had smaller shoulders compared to untreated individuals AMAB (-1.3 cm; 95%CI -2.1; -0.5). In individuals AMAB from both the early and late PS group, pelvic inlet, pubic symphysis width and interischial distance were greater compared to untreated individuals AMAB resulting in dimensions comparable to untreated individuals AFAB. Only in early PS AFAB pelvic inlet width was smaller compared to untreated individuals AFAB (-1.0 cm; 95%CI -1.5; -0.6), and comparable to untreated individuals AMAB. The study results suggest that skeletal dimensions are only altered by GAHT if endogenous puberty has not yet been completed at start of PS. These findings enhance our understanding of hormonal effects on the skeleton and may hold clinical relevance for body image as well as for forensic anthropology. Future research should evaluate clinical implications for surgical or obstetrical outcomes in transgender individuals.

Large-scale analysis to identify risk factors for ovarian cancer

ObjectiveOvarian cancer is characterized by late-stage diagnoses and poor prognosis. We aimed to identify factors that can inform prevention and early detection of ovarian cancer.MethodsWe used a data-driven machine learning...

Contact-force-based closed-loop control of shell structure additive manufacturing with continuous-fiber-reinforced polymer composites

Additive manufacturing (AM) is an automated process for fabricating complex structures, especially for continuous fiber-reinforced polymer (CFRP) composites with exceptional mechanical performance and reduced weight. The extrusion-based CFRP-AM process has been widely adopted but faces challenges with insufficient impregnation/adhesion and lack of geometrical accuracy. Existing research efforts exploit various mechatronics approaches and printing parameter adjustment techniques to enhance CFRP quality. Nevertheless, most of them are static or slow-varying; thus, they cannot dynamically adjust to local geometrical features and faults, which are particularly representative of the CFRP-AM process in high-curvature regions. To enable dynamic and rapid adjustment, this study exploits contact forces as major real-time feedback signals to dynamically control the feed velocity, layer height, and fiber extrusion rate. To create a continuous feedback control environment for dynamic adjustment, the study also proposes a novel helical CFRP-AM printing trajectory generation method for closed shell structures, such that the helical angles indirectly adjust the layer height of the parts. A material extrusion CFRP-AM platform combining a co-extrusion nozzle, an industrial robot, a six-degree-of-freedom load cell, and a real-time closed-loop control system is built to verify the proposed control framework. Three representative case studies are introduced to show the enhancements of the closed-loop CFRP-AM process, particularly in layer height adjustment, high-speed printing, and large curvature regions.