Minimum Change Research Articles

Evaluating the Reliability and Consistency of Treadmill Gait Analysis Using an RGB-D Camera: Effects of Assistance and No Assistance

This study aimed to assess the intraday reliability of markerless gait analysis using an RGB-D camera versus a traditional three-dimensional motion analysis (3DMA) system with and without a simulated walking assistant. Gait assessments were conducted on 20 healthy adults walking on a treadmill with a focus on spatiotemporal parameters gathered using the RGB-D camera and 3DMA system. The intraday reliability of the RGB-D camera was evaluated using intraclass correlation coefficients (ICC 1, 1), while its consistency with the 3DMA system was determined using ICC (2, 1). The results demonstrated that the RGB-D camera provided high intraday reliability and showed strong consistency with 3DMA measurements regardless of the presence of an assistant. The Bland–Atman analysis indicated no significant systematic bias, with the minimum detectable change remaining within acceptable clinical ranges. These findings highlight the potential of the RGB-D camera for reliable markerless gait analysis in clinical environments in which walking assistance may be needed, thereby expanding its applicability in patients with various impairment degrees. Future research should validate these results in patient populations and explore their utility for measuring kinematic parameters.

Reliability of running gait variability measures calculated from inertial measurement units.

Changes to the variability within biomechanical signals may reflect a change in the health of the human system. However, for running gait variability measures calculated from wearable device data, it is unknown whether a between-day difference reflects a shift in system dynamics reflective of a change in human health or is a result of poor between-day reliability of the measurement device or the biomechanical signal. This study investigated the reliability of stride time and sacral acceleration variability measures calculated from inertial measurement units (IMUs). Nineteen runners completed six treadmill running trials on two occasions seven days apart. Stride time and sacral acceleration signals were obtained using IMUs. Stride time variability and complexity were calculated using the coefficient of variation (CV) and detrended fluctuation analysis (DFA), respectively. Sacral acceleration regularity was quantified using sample entropy with a range of input parameters m (vector length) and r (similarity threshold). Between-day reliability was assessed using the intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimum detectable change. Stride time CV displayed moderate relative reliability (ICC = 0.672), but with a large absolute minimum detectable change=0.525%, whilst stride time DFA-α displayed poor relative reliability (ICC = 0.457) and yielded large minimum detectable changes (≥ 0.208). Sample entropy displayed good relative reliability in mediolateral and resultant sacral acceleration signals for certain combinations of the parameters m and r, although again with large minimum detectable changes. Researchers should be cognisant of these reliability metrics when interpreting changes in running gait variability measures in clinical contexts.

The intermetacarpal distance method for assessment of active thumb radial abduction has excellent test-retest agreement, reliability, and precision in persons with non-operative thumb carpometacarpal osteoarthritis.

Limitations in thumb radial abduction (i.e., carpometacarpal extension) are commonly experienced by persons with thumb carpometacarpal osteoarthritis. Restoring this deficit is often a focus of surgical and rehabilitative interventions. Because of this, clinical measures of radial abduction are needed. The ''gold-standard'' assessment of thumb radial abduction is goniometry however it has modest reliability in persons with thumb carpometacarpal osteoarthritis. Conversely, the intermetacarpal distance (IMD) method of assessing radial abduction has promising reliability in healthy persons and excellent inter-rater reliability in those with thumb carpometacarpal osteoarthritis. However, to date, there has been no exploration of its test-retest reliability and precision in persons with thumb carpometacarpal osteoarthritis. Further, while multiple trials are often performed in various hand therapy assessments, it is common practice to take a single measurement of hand joint range of motion. Yet, we do not know if multiple trials might enhance the reliability of these range of motion measurements. The current study aimed to (1) assess the test-retest agreement, reliability, and precision of the IMD method when measuring thumb radial abduction and (2) compare these psychometric properties when reporting one trial, the mean of two trials, and the mean of three trials of the IMD method in people with thumb carpometacarpal (CMC1) osteoarthritis (OA). Prospective Cohort study of test-retest reliability. Purposive sampling was used to recruit adults with radiographically confirmed CMC1 OA. Participants' radial abduction was assessed using the IMD method to measure radial abduction of the affected hand on two separate occasions approximately two weeks apart. Three trials of the assessment were administered at each visit. The Bland Altman method was uses to assess agreement, the intraclass correlation coefficient (ICC2,3) was calculated to examine the reliability, and the standard error of the measurement (SEM), minimum detectable change (MDC) and MDC percentage were calculated to determine the precision of the IMD method for one trial, the mean of two trials, and the mean of three. Descriptive data on demographics and IMD values of the sample were presented. Forty persons with CMC1 OA participated. The mean difference between trials ranged from 0.21 to 0.30 mm, no significant fixed biases (p≥0.48) or proportional biases (p≥0.41) existed between mean test and retest scores, and 38/40 (95%) of test-retest differences fell within the 95% limits of agreement. The Intraclass Correlation Coefficient (ICC2,3) values were 0.942 (0.893-0.968), 0.970 (0.943-0.984), and 0.970 (0.942-0.984) for 1 trial, the mean of two trials, and then mean of three trials respectively. The ICC value of the mean of two trials was significantly higher than that of 1 trial indicating superior reliability however reliability for each approach fell into the excellent range (i.e., >0.90). The precision of one trial (MDC%=13.0) fell into the acceptable range while the precision of the mean of two (MDC%=9.1) and three trials (MDC%=9.1) fell into the excellent range. The IMD method for assessing CMC1 radial abduction has acceptable agreement, excellent test-retest reliability, and acceptable-to-excellent precision when performing one trial, the mean of two or the mean of three trials in persons with CMC1 osteoarthritis. The precision and reliability of the mean of two or three trials were non-superior however the mean of two trials yielded superior reliability and precision to that of a single trial. Changes in IMD measurements of 1.9mm and 1.4mm are needed to exceed measurement error when administering one or two trials respectively and change must surpass 5.3mm and 3.8mm to exceed clinically meaningful thresholds for one or two trials respectively. We recommend taking the mean of two trials over a single trial when using the IMD method for assessing CMC1 radial abduction in persons with CMC1 OA.

Understanding the roles of climate change, land use and land cover change and water diversion project in modulating water- and carbon-use efficiency in Han River Basin.

Water-use efficiency (WUE) and carbon-use efficiency (CUE) are critical indicators of ecosystem function and hydrologic processes, reflecting the water-carbon flux exchange rate. Climatic variables, land use and land cover change (LUCC) and water diversion project (WDP) have altered water-carbon cycle; however, their roles in modulating WUE and CUE remain uncertain. To explore these effects, a framework is proposed and Han River basin (HRB) in China is selected as a case study including the data sets from both remote sensing and in situ observations during 2000-2020. The process-based Regional Hydro-Ecological Simulation System model and a supervised machine learning model are applied to simulate the impacts of climatic variables, LUCC and WDP on WUE and CUE, which are conducted by designing four experiments. We find that no significant WUE and CUE trends attributed to contrasting trends in the dry (October to March) and wet (April to September) seasons. Temperature variations greatly affect WUE and CUE, with WUE decreasing in the wet season and increasing in the dry season due to minimum temperature changes. LUCC has litter impacts on WUE and CUE changes. From 2014 to 2020, the middle route of the South-to-North WDP decreased WUE by 0.22 gCkg-1H2O in the middle-low HRB's wet season, slightly affecting CUE. Seasonal CUE was stable, with the largest decrease of 0.04 in the upper HRB during the wet season. The WDP also increased WUE sensitivities to minimum and maximum temperatures, while CUE sensitivities remained constant. Our case study has proven that the proposed framework is an effective way to understand the roles of climate change and WDP in modulating WUE and CUE.

Intra- and inter-session reliability and repeatability of 1H magnetic resonance spectroscopy for determining total creatine concentrations in multiple brain regions.

Using proton magnetic resonance spectroscopy (1H MRS) to determine total creatine (tCr) concentrations will become increasingly prevalent, as the role of creatine (Cr) in supporting brain health gains interest. Methodological limitations and margins of error in repeated 1H MRS, which often surpass reported effects of supplementation, permeate existing literature. We examined the intra- and inter-session reliability and repeatability of 1H MRS for determining tCr concentrations across multiple brain regions (midbrain, visual cortex and frontal cortex). Eighteen healthy adults aged 20-32 years were recruited (50% female; n=14 intra-session; n=15 inter-session). 1H Magnetic resonance imaging and spectroscopy were completed at 3T. Intra-session analyses involved repeated 1H MRS of the midbrain, visual cortex and frontal cortex without participant or voxel repositioning, whereas inter-session analyses involved measurements of the same regions, but with participant and voxel repositioning between repeated measurements. The 1H MRS data (174 spectra) were analysed using TARQUIN and OSPREY, and voxel fractions (grey/white matter and CSF) were determined using segmentation. Our findings show that tCr concentrations can be determined reliably and repeatably using 1H MRS, within an error of <2%, and that large inter-regional differences in tCr concentration are present in the human brain. We provide new minimum detectable change data for tCr concentrations, a detailed discussion of the inherent error sources in repeated 1H MRS, including the substantial effect of the analysis package on tCr quantification, and suggestions for how these should be managed to improve the interpretability and clinical value of future research. More studies are needed to determine whether our findings can be replicated in other centres and different populations.

The effect of denosumab on minimum 3-years BMD changes in patients with osteoporotic hip fractures: a propensity score matching analysis.

Denosumab, a potent antiresorptive agent, has been recognised to increase bone mineral density (BMD) and reduce fracture risk in vertebrae and hips. Despite its widespread use, no sequential follow-up studies have investigated its effects on BMD in patients with hip fractures. This study aimed to analyse the effect of denosumab on BMD gain in patients with hip fractures and investigate the incidence of subsequent hip fractures. This retrospective study analysed 371 patients treated with denosumab for at least 3years, including 122 patients with hip fractures. 1:1 propensity score matching was used to compare BMD changes in the lumbar spine, total hip, and femoral neck, as well as additional hip fracture incidence between the hip fracture and the other than hip fracture group. Ultimately, 122 patients in each group were compared. Subgroup analysis compared osteoporosis medication-naïve patients with those with prior medication use. The hip fracture and other than hip fracture group exhibited significant annual increases in lumbar spine and total hip BMD, with no significant differences between them after matching. The femoral neck BMD increased significantly only in the first year. The incidence of additional hip fractures did not differ significantly between the groups. Moreover, the effect of denosumab on BMD increase was more pronounced in patients without a previous medication history for anti-osteoporosis treatment than in those with such a history. Denosumab significantly increased lumbar spine and total hip BMD in patients with hip fractures, with comparable efficacy to that in other than hip fracture patients. Its effect was more pronounced in medication-naïve patients, suggesting its efficacy regardless of hip fracture status.

Test Weight Validation in Preterm Infants.

Objective: Accuracy in the assessment of feed intake is important for preterm infants at risk of growth failure. Clinical observation tools are unvalidated in this population, and test weight measurement may be inaccurate in preterm infants taking small feed volumes. Methods: Test weights were performed to assess agreement between weights using a standardized protocol and a feed of known weight in preterm infants (born at <35 weeks gestational age [GA]) during their transition to oral feeding. Reproducibility was assessed using two repeated measurements in each participant. Agreement between test weights and known feed weights was assessed, and minimal detectable change was calculated. Results: Thirty-eight preterm infants (GA 30 + 5 (28-33 + 1), birth weight 1574 g (+/- 671 g)) were recruited and had test weights performed at CGA 35 + 3 (± 10 days). Each infant was weighed twice before and twice after each measured feed, and a high degree of reproducibility was found for both the paired pre-feed weights, ICC = 0.99 [0.99-0.99] and the paired post-feed weights, ICC = 0.99 [0.99-0.99]. The mean absolute difference between test weight and feed weight was 1.7 g (±2.2). We calculated the minimum detectable change as 0.96 g, representing the magnitude of change below which there is more than 95% chance that no real change occurred. Conclusions: During the establishment of oral feeds, a standardized protocol at the bedside for repeated pre- and post-feed weights demonstrated a high degree of reproducibility. Based on our data, test weight measurements are appropriate for use in this preterm population during the establishment of oral feeds.

The Reliability and Validity of a Novel Clinical Test for Assessing Shoulder Rotation ROM in Collegiate Baseball Players: Functional Assessment of System Tension of the Shoulder (FAST-SHDR).

Traditional methods to measure rotational passive range of motion (PROM) in the throwing shoulder do not reflect the complexity of the throwing motion. Therefore, a sport specific shoulder rotation PROM test (FAST-SHDR) was developed and compared to traditional standard methods to measure shoulder internal and external rotational PROM in the throwing shoulder. The aim of this study was to determine the intra-rater reliability of the FAST-SHDR test in young, healthy, male Division 1 baseball players. Reliability and validity analysis. A study with 49 healthy participants (31 collegiate baseball players, 18 controls) examined a sport specific shoulder rotation PROM test (FAST-SHDR) and compared this to the standard supine 90/90 shoulder in a single session assessment. Intra-class correlation coefficient (ICC), standard error of measurement (SEM) and minimum detectable change (MDC) were calculated. Within and between group differences were based on t-tests (p<0.001), absolute differences and effect sizes (95% CIs). The novel test (FAST-SHDR) had good to excellent reliability with ICCs ranging from 0.95 (0.89 to 0.98) to 0.96 (0.92-0.98). MDC ranged from 7°-11° which is equivalent to 11-14% of mean PROM scores. In the dominant shoulder of baseballers, when FAST-SHDR IR/ER was compared to standard IR/ER testing the FAST-SHDR scores were lower for both IR (MD 23.3°; 95% CI 19.7-26.8) and ER (MD 50.7°; 95% 44.7 to 56.7). Comparing the shoulder rotation PROM in baseballers, the FAST-SHDR ER and IR measurements were significantly lower (p<0.0001) when compared to traditional standard PROM testing for shoulder IR and ER rotation. FAST-SHDR testing shows good to excellent intra-rater reliability for measuring shoulder rotational PROM and demonstrates both face and discriminant validity. 3.

Development, Validity, and Reliability of Adolescent Motivation Inventory-Cerebral Palsy

Objectives: Motivation is the most influential factor in the drive and performance of adolescents with cerebral palsy (CP). As identification and analysis of volition in Iranian adolescents with CP seem to be essential, designing appropriate tools for assessing their motivation is crucial. To achieve this goal, we developed an adolescent motivation inventory-CP (AMI-CP) and evaluated its psychometric properties. Methods: In the first phase, item generation was conducted. Next, in the second phase, face and content validities of the items were assessed. Moreover, construct validity was assessed by exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). A total of 304 adolescents with CP participated in the EFA, while 210 adolescents with CP participated in the CFA. Afterward, convergent and discriminant validities of the inventory were measured. Moreover, reliability was evaluated by calculating Cronbach α, McDonald’s omega, average inter-item correlation, composite, and test re-test reliability. Lastly, the standard error of measurement (SEM) and the minimum detectable change (MDC) were applied. Results: Five factors with 22 items were extracted by EFA, accounting for 50.42% of the variance. The results of model fit indexes confirmed the goodness-of-fit of the final model with 20 items. In addition, the AMI-CP had a Cronbach α value of 0.75 and an intra-class correlation coefficient of 0.94. Moreover, the SEM and MDC of the inventory were 2.63 and 7.31, respectively. Discussion: The AMI-CP is a helpful measure of motivation in adolescents with CP. This inventory can enhance the assessment of the CP adolescents’ motivation by evaluating values, interests, personal causation, and physical and social environments.

Neat ammonia use in a heavy-duty diesel engine converted to spark ignition focused on lean operation

Ammonia is a prime fuel alternative in the global effort of decarbonizing the transportation and power generation sectors. However, ammonia suffers from poor combustion characteristics including a lower burning velocity, a higher ignition energy, a lower calorific value, and narrower flammability limits when compared to conventional hydrocarbons. This study investigated the potential for fueling neat ammonia to a single-cylinder heavy-duty four-stroke research diesel engine converted to natural gas spark ignition operation. Stable neat ammonia combustion, for the first time focused on lean operation, was performed without any hardware modifications or engine control strategies other than the adjustment of the spark timing. Experiments were performed at various low to medium engine loads when compared to the maximum load of the non-converted original diesel engine, for engine speeds ranging from 800 rpm to 1400 rpm and equivalence ratios from 0.8 to 1.05. Results indicated that pure ammonia operation did not produce any penalty on engine performance or combustion stability when compared to methane operation at similar conditions and same fuel energy per cycle. Moreover, neat ammonia engine performance was better at the lean equivalence ratio, mostly driven by the associated increase in intake pressure when fuel energy per cycle was kept constant. In addition, as the data showed the capability of stable ammonia combustion for a wide range of speeds and loads (at least for the engine platform used in these experiments), this study confirmed the potential of converting current heavy-duty diesel engines to neat ammonia spark operation with minimum changes in hardware and/or control.

Reliability and Validity of the KFORCE Sens® Inertial Sensor for Measuring Cervical Spine Proprioception in Patients with Non-Specific Chronic Neck Pain.

Patients with non-specific chronic neck pain (NSCNP) exhibit sensorimotor disturbances, with proprioception impairment considered an important aspect. The aim of this study was to assess the reliability and validity of a novel inertial sensor-based electrogoniometer (KFORCE Sens®) for cervical spine (CS) proprioception measurement in patients with NSCNP. The within-day intra-rater reliability of CS proprioception and its association with patient demographics and clinical status were examined in fifty-nine patients with NSCNP, aged between 25-65 years, recruited from primary care. CS proprioception was examined via angle reproduction, in angles set mid-range in the available CS range of motion (ROM) in each motion direction. The clinical status evaluation comprised the maximum and average pain intensity in the last week, disability, fear of movement/re-injury, catastrophizing, neck awareness, and CS-ROM. Reliability was assessed using the intraclass correlation coefficient (ICC2,1), standard error of the measurement (SEM), and minimum detectable change (MDC95%). Pearson's R assessed between-measures associations. CS proprioception reliability was good (ICC2,1 = 0.75-0.89), with low measurement error (SEM = 1.38-3.02° and MDC95% = 3.83-8.38°). Correlations between participants' CS proprioception and their clinical status or demographics were not significant. The reliability of CS proprioception assessment with the KFORCE Sens® was good in a sample of mildly to moderately disabled patients with CNP and thus deemed suitable for further research in this field.

BBCEAS-HLPC measurements for synthetic antioxidants (TBHQ, BHA, and BHT) in deep-UV region below 300 nm

This study investigates the integration of Broadband Cavity Enhanced Absorption Spectroscopy (BBCEAS) with High-Performance Liquid Chromatography (HPLC) to detect synthetic antioxidants; BHA, BHT, and TBHQ in the deep-UV region below 300 nm. The research addresses the need for more sensitive and cost-effective detection methods in HPLC systems, particularly for low analyte concentrations, by exploring BBCEAS as a superior alternative to conventional detectors that often fall short in sensitivity. The sensitivity of the HPLC-BBCEAS system is assessed by calculating the minimum detectable change in the absorption coefficient (αmin) and comparing with those obtained using conventional HPLC and single-wavelength HPLC-CRDS methods. The findings demonstrate that the HPLC-BBCEAS system achieves αmin values of 1.8 × 10−5 cm−1 for BHA, 2.8 × 10−5 cm−1 for BHT, and 1.9 × 10−5 cm−1 for TBHQ at 280 nm, with Limits of Detection (LOD) and Quantification (LOQ) up to 30 times lower than conventional HPLC systems.

Construct validity and reliability of the 2-minute step test in patients with lumbar spinal stenosis

Aim This study aimed to investigate the validity and reliability of the 2-Minute Step Test (2MST) in patients with lumbar spinal stenosis (LSS). Method This cross-sectional study involved 55 volunteers, aged 18–80, diagnosed with lumbar spinal stenosis. The participants were assessed using the 2MST, the 2-Minute Walk Test (2MWT), the 6-Minute Walk Test (6MWT), the Visual Analogue Scale (VAS), and the Oswestry Disability Index (ODI). To evaluate the reliability of the 2MST, test-retest reliability was determined by administering the 2MST again after a 7-day interval. The reliability analysis included the intraclass correlation coefficient (ICC) with a 95% confidence interval (CI), standard error of measurement (SEM), and minimum detectable change at the 95% confidence level (MDC95). For concurrent validity, the correlations of the 2MST with the 2MWT, 6MWT, and ODI were assessed. Results The 2MST exhibited excellent test-retest reliability (ICC = 0.94, SEM = 5.56, MDC95=15.41) in LSS patients. Additionally, the 2MST showed significant correlations with the 2MWT (r = 0.842, p < 0.001), 6MWT (r = 0.819, p < 0.001), and ODI score (r = −0.722, p < 0.001). Conclusion This study demonstrated that the 2MST is a valid and reliable tool for assessing exercise capacity in individuals with LSS. ClinicalTrials.gov ID NCT06060821

Intra-rater and inter-rater reliability of a handheld myotonometer measuring myofascial stiffness of lower lumbar myofascial tissue in healthy adults.

Biomechanical muscle properties, such as stiffness, can be valuable indicators of tissue health and show promise as a diagnostic and treatment measure for chronic low back pain (CLBP). The development of accessible assessment technologies, such as the MyotonPRO portable device, allows for the convenient quantification of muscle tone and stiffness changes. The aim of this study is to assess the reliability of lumbar erector spinae muscle stiffness with the MyotonPRO in healthy adults and to compare stiffness changes between prone and sitting position. Thirty asymptomatic participants (N = 15 women and N = 15 men) aged between 18 and 65 years were recruited to participate in this study. Two examiners tested muscle stiffness at the palpable muscle belly, one finger away from the spinous process at the level of the L4 vertebra, first from the left and then from the right side, both in prone position and after in sitting position. For inter-rater reliability, all participants were tested by two examiners on the same day, and intra-rater reliability was calculated using the same examiner's assessment results with an exact 24-h interval. Intraclass correlation coefficients (ICC), standard error measures (SEM) and minimum detectable change (MDC) with a 95% confidence interval were calculated to assess intra-rater and inter-rater reliability. Statistical analysis revealed good intra-rater reliability with an ICC of 0.88 (95% CI [0.76-0.94]) for the stiffness of the left erector spinae and excellent intra-rater reliability with an ICC of 0.91 (95% CI [0.82-0.95]) for the right erector spinae, both in the prone position. Intra-rater reliability in the sitting position was excellent to very good with an ICC of 0.91 (95% CI [0.82-0.96]) for the left side and an ICC of 0.89 (95% CI [0.78-0.95]) for the right side. The results for the left-sided prone position showed good inter-rater reliability with an ICC of 0.87 (95% CI [0.73-0.94]). The prone position on the right side also showed good inter-rater reliability with an ICC of 0.84 (95% CI [0.68-0.92]). The inter-rater reliability for the left and right side in the sitting position was excellent with an ICC of 0.96 (95% CI [0.92-0.98]) for the left side and an ICC of 0.95 (95% CI [0.90-0.97]) for the right side. This study demonstrated high reliability in measuring lumbar erector spinae muscle stiffness with the MyotonPRO in healthy adults and the ability of the device to detect even small changes in erector spinae muscle stiffness, testing both the right and left sides and measuring in both prone and sitting positions. The use of the sitting position to assess lumbar tissue tension in individuals may serve as a valuable substitute for the prone position, particularly for patients who experience discomfort in the prone position, and could have additional practical significance in clinical settings.

Intra-rater and inter-rater reliability of the fixed plumb line for postural and scoliosis assessment in the sagittal plane: a pilot study.

The plumb line (PL) is a common tool for assessing the sagittal curvatures of the spine, but its accuracy depends on the ability of the physician to use it correctly. This study aimed to present a fixed plumb line (FPL) no longer held by a physician but fixed to a support, evaluating the reliability in posture assessment, comparing it with PL in both adolescent with and without scoliosis. The study evaluated the sagittal distances of the spine using a PL and a FPL in 80 young adults aged between 28.7±7.2 and 55 adolescents aged between 12.4±2.3, with and without scoliosis. Two expert and two novice clinicians tested the patients to evaluate the intra-rater and inter-rater reliability of FPL. Each clinician assessed participants twice on the same day, with a predetermined time interval (>1 h) to reduce recall bias. Multi-factor multivariate analysis of variance and two-way analysis of variance assessed the statistical significance, while intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimum detectable change (MDC) validated FPL consistency. FPL provided an ICC coefficient >0.90 for all the measures, while PL an average of 0.70. On AIS patients, PL and FPL showed a significant difference for C7 p<0.001 and T12 p<0.001. The measured parameters were sensitive to gender and age for the FPL, furthermore, the C7 and L3 measurements were statistically different between PL and FPL (p<0.001). Intra-rater reliability results for FPL ranged from 0.94 to 0.98 across various parameters, while the SEM and MDC values underscore the valuable precision of the FPL with changes exceeding 1 cm being meaningful. These findings suggest that FPL could be a reliable and accurate tool for measuring sagittal distances of the spine in both scoliotic and non-scoliotic patients.

Study on Spatial Scale Selection Problem: Taking Port Spatial Expression as Example

Spatial scale is a key factor, which affects the accuracy of spatial expression and further influences the spatial planning of a research area. In order to help improve the efficiency and accuracy of optimal scale selection for all sizes of research areas, a universal two-layer theoretical framework for optimal scale selection was proposed in this paper. Port area was taken as an example to systematically clarify the application of the proposed framework, and the scale selection model for port spatial expression was established. Least-squares-based mean change point analysis was introduced into the model, and the concept of a comprehensive change point was proposed to form the criterion for optimal port scale selection. First, an appropriate scale domain was preliminarily determined by the upper scale selection model. Then, the lower scale selection model determined the final appropriate scale domain and took the corresponding scale of a minimum comprehensive change point as the final optimal scale for port spatial expression. Finally, a port area in Qingdao in eastern China was taken to verify the feasibility of the proposed model, and the optimal scale was suggested to be 14 m. The proposed framework in this paper helps ensure the accuracy of spatial expression and reduce spatial data redundancy, and it can provide the methodological references for planners to better spatialize a research area, which will guarantee the subsequent spatial planning work.

Age-Related Differences and Reliability of a Field-Based Fitness Test Battery in Young Trained Footballers: The Role of Biological Age.

the purpose of this study was to analyze the reliability of a field-based fitness test battery in young trained football players, according to biological age. 197 young trained football players (12-19 years old) participated in the study. We measured anthropometric measurements (i.e., height, sitting height, length leg, and body mass), a bilateral vertical jumping test (CMJ), a progressive loading test of squats and hip thrust, acceleration and speed tests (10 m and 30 m sprint tests), a change-of-direction ability test (V-cut test), and a cardiorespiratory fitness test (30-15 intermittent fitness test). Statistical data are shown as the mean ± standard deviation by PHV group in tests and retests. Test reliability was assessed through the intraclass correlation coefficient (ICC), with an ICC above 0.9 being considered high. To evaluate accuracy and repeatability, standard error of measurement, coefficient of variation, and minimum detectable change at 90% were determined and Bland-Altman diagrams were used, establishing a statistical significance of p < 0.05. All of the tests showed non-significant differences between the test and retest in the pooled sample (p > 0.05). Furthermore, all of them presented a trivial effect size (<0.2) and high intraclass correlation coefficients (>0.9), which indicates the high reproducibility of the tests, despite some of them presenting a significant difference between trials (i.e., the CMJ, 10 m sprint, V-cut, and squat tests). Low measurement errors were found for all tests (coefficient of variation [CV] = 4.39-9.39), except for the CMJ and the progressive loading test for squat and hip thrust exercises (CV = 12.2-21.11). Similar results were found irrespective of biological age group. All tests were reliable for the pooled sample as well as for the biological age groups.

Features of the change in the thermal coefficient of electrical resistance upon heating electrically conductive composites of crystallizable polyolefins with carbon black

Objectives. To investigate electrically conductive polymer composite materials (EPCMs) based on crystallizable polyolefins and electrically conductive carbon black for the production of self-regulating heaters; to study the mechanism of the occurrence of positive and negative temperature coefficients (PTC and NTC) upon heating such composites.Methods. A comprehensive study of the structure and properties of crystallizable EPCMs with electrically conductive technical carbon was carried out. In order to measure the electrical characteristics of the composites, they were compacted into plates to model polymer heaters. Contact electrodes made of an ungreased brass mesh were embedded in their ends. The temperature dependencies of the electrical characteristics of the samples were investigated in a modified thermal chamber of an FWV 633.10 Vicat softening temperature meter. The change in the degree of crystallinity was analyzed by means of differential scanning calorimetry with a NETZSCH DSC 204 F1 Phoenix calorimeter. The dilatometric and rheological characteristics of the samples were studied using an IIRT-AM melt flow index tester.Results. It was determined that the self-regulation ability (an abnormally high positive thermal coefficient of electrical resistance) of selfregulating heaters made of composites of crystallizable polyolefins with electrically conductive technical carbon cannot be explained by the thermal expansion of EPCMs alone. It was shown that in crystallizable polyolefin-based EPCMs, the inversion of the thermal coefficients of electrical resistance (transition from PTC to NTC) is associated with a change in the aggregate state of EPCMs and the beginning of its transition to a viscous-flow state. A mechanism involving a sharp increase in the electrical resistance of self-regulating crystallizable polyolefin-based composite with electrically conductive technical carbon was proposed and substantiated. This mechanism takes into account the additional shear deformation effect produced on the crystalline phase of the EPCM by numerous expanding melt microvolumes formed at the early stages of the melting process with a minimum change in the degree of crystallinity.

Inter- and intra-examiner reliability of short-term measurement of heart rate variability on rest in patients hospitalized with COVID-19

Measures reflecting cardiac sympathovagal activity, particularly those associated with heart rate variability (HRV), are widely recognized and utilized in both scientific and clinical contexts. This study aimed to assess the inter- and intra-examiner reliability of short-term HRV parameters in patients hospitalized with coronavirus disease 2019 (COVID-19). A total of 103 patients (both sexes) diagnosed with COVID-19 were included in the study. HRV was analyzed using both linear and nonlinear methods. Reliability was evaluated through intraclass correlation coefficient (ICC2.1), minimum detectable change (MDC), standard error of measurement (SEM), and coefficient of variation (CV). According to Fleiss’ criteria, excellent reliability was demonstrated, with ICC values ranging from 0.970 to 0.999 for Examiner 1, and from 0.956 to 0.999, for Examiner 2. In the inter-examiner analysis, the ICCs of HRV parameters ranged from 0.972 to 0.999. SEM values for intra-examiner reliability for Examiner 1 ranged from 0.02 to 5.64, with MDC values from 0.05 to 15.64, and CV (%) from 0.28 to 8.04. For Examiner 2, SEM values ranged from 0.02 to 8.18, MDC values from 0.05 to 22.68, and CV (%) from 0.24 to 8.14. For inter-examiner reliability, SEM values ranged from 0.02 to 6.17, MDC from 0.06 to 17.11, and CV (%) from 0.34 to 9.81. Across all analyses, CVs for HRV parameters remained below 10%. Considering different time points and different examiners, short-term resting HRV measurements in patients hospitalized with COVID-19, as evaluated using a portable heart rate device, exhibit high reliability.

Psychometric property of the Japanese version of self-efficacy for managing chronic disease scale in individuals with chronic diseases

BackgroundAlthough accurately assessing self-efficacy for self-management is crucial in chronic illness care, important, there is a scarcity of validated psychometric properties in Japan. This study aimed to validate a Japanese version of the Self-Efficacy for Managing Chronic Disease (SEMCD-J) scale. MethodsIndividuals with self-reported chronic diseases, symptoms, or conditions for over one year were recruited online. The SEMCD-J was translated through translation, back translation, and cognitive interviews with 15 participants. Patient Health Questionnaire-9 (PHQ-9) and Center for Disease Control and Prevention Healthy Days Core Module-4 (CDC-HRQOL-4) were used to evaluate the scale's validity. Test-retest reliability was assessed two weeks after the initial measurement. ResultsOf 500 participants, 494 were analyzed and 149 were analyzed for test-retest reliability. The mean item score was 5.54 ± 2.12. Confirmatory factor analysis (CFA) with a 1-factor model showed good fit (CFI = 0.94, TLI = 0.90, RMSEA = 0.23, SRMR = 0.04). CFA with a 2-factor model showed better fit (CFI = 0.99, TLI = 0.98, RMSEA = 0.11, SRMR = 0.01). Cronbach's α of the total, Factor 1, and Factor 2 were 0.97, 0.97, and 0.92. Their item-total correlations ranged from 0.88 to 0.95, 0.93 to 0.97, and 0.92 to 0.93, respectively. Their interclass correlation coefficients were 0.63, 0.58, and 0.66, respectively. The minimum detectable change was 3.56. Pearson's correlation analyses indicated that SEMCD-J was significantly associated with PHQ-9 (r = −0.57, p < 0.001) and the dimensions of CDC-HRQOL-4, namely, the degree of general health (r = −0.55, p < 0.001), physically unhealthy days (r = −0.46, p < 0.001), mentally unhealthy days (r = −0.48, p < 0.001), and functionally unhealthy days (r = −0.50, p = < 0.001). ConclusionThe validity and reliability of the SEMCD-J were indicated to be acceptable.