Activation Volume Research Articles

Analysis of Water Adsorption Capacity, Thermal Behavior, Antioxidant Activity, and Smoke Volume by Polyol Ester in Reconstituted Tobacco.

A series of ester derivatives with hydroxyl groups were created by esterification of 1,2-propanediol and glycerol with o-toluoyl chloride via the catalyst 4-dimethylaminopyridine (DMAP). All the compounds were verified using nuclear magnetic resonance (1H NMR, 13C NMR), infrared spectroscopy, and high resolution mass spectrometry. Moisture absorption and desorption experiments were carried out on the compounds' pure systems and their systems in reconstituted tobacco, while their hygroscopicity and moisturizing properties were evaluated using low-field nuclear magnetic resonance imaging. Two compounds with better absorption and moisture retention were selected: 4 (1-hydroxypropan-2-yl 2-methylbenzoate) and 6 (2,3-dihydroxypropyl 2-methylbenzoate), respectively. Moreover, the thermal stability of compounds 4 and 6 were investigated using thermogravimetric (TG) analysis. The results of TG-DTG showed that the maximum mass loss rate of compound 4 appeared at 251.67 °C, with a mass loss rate of 87.61%. At the peak temperature of 291.83 °C, 6 showed the highest decomposition rate with 49.23% mass loss rate. To explore the antioxidant properties, we constructed three different antioxidant systems. Furthermore, compound 6 showed excellent effects, with scavenging rates reaching 69.28%, 71.92%, and 75.93%, respectively. Smoke volume results indicated that the compounds optimally replaced propanediol and glycerol at a rate of 40%. The results provide a theoretical reference for the development of new moisturizing agents based on polyol esters in the tobacco industry.

Diurnal patterns of accelerometer-measured physical activity and sleep and risk of all-cause mortality: a follow-up of the National Health and Nutrition Examination Surveys (NHANES)

BackgroundPhysical activity and sleep are established modifiable lifestyle factors, but the optimal time of the day of these behaviours for health is unknown. This study examined the independent and joint associations of diurnal patterns of physical activity and sleep with all-cause mortality.MethodsThis prospective cohort study included 6,673 participants who have attended the accelerometer assessment in the 2011–2014 National Health and Nutrition Examination Surveys (NHANES). Diurnal patterns of accelerometer-measured physical activity and sleep were identified using K-means clustering analysis. All-cause mortality was ascertained from the accelerometer measurement to December 31, 2019 (median follow-up 6.8 years). Survey-weighted Cox proportional hazard models were performed to estimate the independent and joint associations of diurnal patterns of physical activity and sleep with all-cause mortality.ResultsDiurnal patterns identified were: early-morning (32.4%), midday (42.5%), and late-afternoon (25.1%) for physical activity; and irregular sleep (37.4%), morning lark (33.6%), and night owl (29.0%) for sleep. After adjusting for volume of physical activity, sleep duration and other potential covariates, the early-morning physical activity pattern (hazard ratio 1.36, 95% confidence interval 1.13–1.64) and irregular sleep pattern (1.42, 1.01–1.99) were independently associated with higher risk of all-cause mortality, compared with midday physical activity and morning lark sleep patterns, respectively. In addition, participants with the combined pattern of early-morning physical activity and irregular sleep had higher risk of all-cause mortality compared to those with midday physical activity combined with a morning lark sleep pattern (1.92, 1.33–2.78). Several sociodemographic differences were observed in the strength of these associations.ConclusionsWearable activity-rest monitoring data showed that peak physical activity in the early morning and irregular sleep diurnal patterns are associated with increased mortality risk, and the combination of these patterns further exaggerated the risk. Public health program should acknowledge that the diurnal patterns of physical activity and sleep, in addition to their duration and frequency, may play a crucial role in lifestyle-based health promotion and management strategies.

Physical fitness of students of different physical health

The main didactic principle of physical education of students is the principle of accessibility (differentiation). Differentiation is based on individual capabilities of groups homogeneous in terms of physical health. Objective: to substantiate the physical prerequisites for differentiated physical education of students, taking into account their level of physical health. Material and methods. The study involved 102 first-year and second-year higher education students. The choice of these students was due to low physical fitness and deteriorating health. The study used analysis and synthesis of scientific and methodological sources, pedagogical testing of physical qualities, express assessment of physical health, and sample statistical method. Conclusions: the content of physical activity (volume and intensity, duration of recovery between bouts and series of exercises) is primarily determined by the level of health of participants. Among female students, this is an average level of physical health, and among male students is an above average level. The worst physical abilities are associated with a below average level of physical health. This may be the basis for a differentiated assessment of physical fitness.

Microfluidic-Integrated Chip Resonators for Electron Spin Sensing in Submicromolar, Submicroliter Solutions.

Planar or chip microresonators decrease the sample volume required for magnetic resonance spectroscopies to the nanoliter scale. However, the interrogation of nanoliter-scale solution samples on planar sensors is hindered by the lack of microfluidic devices that can simultaneously provide a small total volume and long-term sample stability. Here, we report microfluidic devices that decrease the total required sample volume to the submicroliter scale and also provide long-term physical stability and storability. We also report a 3D-printed microfluidic with a self-contained actuation mechanism, which allows the sample to be retracted from the microresonator surface for storage. The microfluidic devices are fabricated easily by laser cutting or 3D printing and are integrable with a broad range of planar sensors. We use planar inverse anapole (PIA) microresonators to obtain continuous wave (CW) electron paramagnetic resonance (EPR) spectra of natural-isotopic-abundance nitroxide radicals, which are ubiquitously used as reporters of biomolecular dynamics. We provide experimental evidence for a concentration sensitivity of 330 ± 40 nmol L-1, a concentration sensitivity limit of 800 ± 100 nmol L-1/mT√Hz, and an active volume no greater than 30 nL. Together, these developments represent an advance not only in the sensitivity of EPR spectroscopy but also in the design of microfluidics for stable, dead-volume-free placement of nanoliter-scale volumes of solutions on planar sensors.

Association between physical activity and mortality in patients with osteoporosis: a cohort study of NHANES.

To determine the impact of physical activity on mortality in osteoporotic patients. A total of 5606 participants were included in this study, including 716 osteoporosis patients. Physical activity was assessed using standardized questionnaire. Participants were categorized into four groups: inactive (no physical activity), low active (physical activity volumes < 150min/week), moderate active (≥ 150min/week but < 300min/week), and high active (≥ 300min/week). Multivariable Cox regression models, using the inactive group as the reference and adjusted for potential confounders, were performed to estimate the hazard ratio (HR) and 95% confidence interval (CI). Osteoporotic patients demonstrated higher mortality rates attributed to various causes compared to non-osteoporosis participants. Physical activity was associated with lower mortality regardless of osteoporosis status. However, Multivariable Cox regression analysis indicated that among osteoporosis patients, only those engaging in ≥ 300min/week physical activity experienced a significant decrease in mortality (all-cause mortality, HR (95% CI) 0.453 (0.268, 0.767) and cardiovascular mortality, HR (95% CI) 0.521 (0.259, 1.049)), surpassing the threshold of 150min observed in non-osteoporosis patients. In sensitivity analysis, or when the proportion of vigorous physical activity was included as a confounder in the multivariate Cox regression analysis, only the high active group still showed a significant reduction in mortality. No significant interactions were observed when the analysis was stratified according to age, sex, and body mass index (P for interaction > 0.05). Restricted cubic spline analysis revealed a linear relationship between physical activity volume and all-cause mortality (P < 0.01 [overall] and P = 0.470 [non-linearity]) and cardiovascular-specific mortality (P = 0.003 [overall] and P = 0.610 [non-linearity]) in patients with osteoporosis. In contrast, these relationships were non-linear in participants without osteoporosis. Patients with osteoporosis need to engage in ≥ 300min/week physical activity to significantly reduce their mortality risk. And the higher the volume of physical activity, the lower the risk of death.

Slowly expanding lesions are associated with disease activity and gray matter loss in relapse-onset multiple sclerosis.

Slowly expanding lesions (SELs) have been proposed as novel MRI markers of chronic active lesions in multiple sclerosis (MS). However, the mechanism through which SELs affect brain volume loss in patients with MS remains unknown. Additionally, the prevalence and significance of SELs in Asian patients with MS remain unclear. This study aimed to investigate the association between SELs and no evidence of disease activity (NEDA)-3 status as well as brain volume loss in Japanese patients. A total of 99 patients with relapse-onset MS were retrospectively evaluated. SELs were identified on brain MRI based on local deformation when consecutive scans were registered longitudinally. We developed a logistic regression model and generalized linear mixed models (GLMMs) to evaluate the association between the number of SELs and disease activity and changes in brain volume. During the observation period (2.0±0.22years), 35 patients developed at least one SEL. Multivariable logistic regression analysis showed that ≥2 SELs were associated with 0.2 times the risk of achieving a NEDA-3 status. GLMMs revealed that the number of SELs was negatively associated with volume changes in the cortex (p=.00169) and subcortical gray matter (p=.00964) after correction for multiple comparisons. SELs were identified in Japanese patients with MS during the 2-year observation period. The number of SELs is associated with disease activity and brain volume loss, suggesting that the number of SELs could be a biomarker of disease activity in MS.

The impact of physical activity on the prevalence of edentulism: an analysis of the relationships between active lifestyle and dental health.

Edentulism is considered the ultimate sign of oral health disease burden. It is a common and frequent clinical disease, mostly seen in the elderly, which has been reported to be closely associated with many diseases. While physical activity is known to benefit many chronic diseases, the relationship between the volume of physical activity and edentulism remains unclear. The CHARLS provided the data for this study. A total of 6,480 participants were enrolled in this study, of whom 46.02% were male and 53.98% were female. The edentulism was defined according to self-report and physical activity volume can be represented by metabolic equivalents. Multiple logistic regression, smooth curve fitting, threshold effects analysis, and Cox regression models were used to explore the relationship between physical activity volume and edentulism. In the fully adjusted model, physically active participants had a 24% lower risk of edentulism compared to those who were physically inactive. Then, we subdivided participants with adequate physical activity into four levels: 600 ≤ PAV < 1200; 1200 ≤ PAV < 1800; 1800 ≤ PAV < 3000; and PAV ≥ 3000. We found that the risk of developing edentulism was lowest and statistically significant at the level of 1,800-3,000 MET-minutes/week physical activity volume (OR = 0.41; 95% CI, 0.24-0.69, p < 0.001). A U-shaped relationship between physical activity volume and edentulism with an inflection point of 2514 (MET-minutes/week) was observed. The results of the longitudinal study also confirm the benefits of physical activity volume with edentulism, participants with adequate physical activity volume had a 21% lower risk of developing edentulism than participants with inadequate physical activity volume (HR = 0.79; 95% CI, 0.67-0.94, p = 0.008). This study reveals a U-shaped relationship between physical activity volume and edentulism. Physical activity reduces the risk of developing edentulism in middle-aged and older populations, but it is important to control the appropriate volume of physical activity.

An exploratory study of functional brain activity associated with gross motor function improvement in children with unilateral cerebral palsy

ABSTRACT Purpose Identify relations of gross motor function and primary motor cortex (M1) functional activity pre and post gross motor interventions for children with unilateral cerebral palsy (UCP). Methods Thirteen children with UCP completed a gross motor intervention. Pre/post-intervention functional MRI outcomes included the laterality index (LI), activation volume, and spatial overlap of M1 activation during active ankle dorsiflexion. Advanced gross motor function (Challenge) was assessed pre/post-intervention, and 2–6 months later. Bivariate correlations and linear regression assessed relations between neuroimaging and motor function. Results Mean pre-intervention M1 activity was contralateral during dominant (LI = +0.85, SD 0.21) but variable during the affected (LI = +0.43, SD 0.57) ankle dorsiflexion. Changes in motor function and neuroimaging outcomes were not significantly associated. However, smaller affected ankle activation and less spatial overlap between ankle activations pre-intervention predicted Challenge improvements post-intervention (adjusted R2 = 0.74, p = .001.) Conclusions This exploratory study identified pre-intervention neuroimaging predictors of post-intervention improvements in advanced gross motor function.

Empatica E4 Assessment of Child Physiological Measures of Listening Effort During Remote and In-Person Communication.

Telepractice is a growing service model that delivers aural rehabilitation to deaf and hard-of hearing children via telecommunications technology. Despite known benefits of telepractice, this delivery approach may increase patients' listening effort (LE) characterized as an allocation of cognitive resources toward an auditory task. The study tested techniques for collecting physiological measures of LE in normal-hearing (NH) children during remote (referred to as tele-) and in-person communication using the wearable Empatica E4 wristband. Participants were 10 children (age range: 9-12 years old) who came to two tele- and two in-person weekly sessions, order counterbalanced. During each session, the children heard a short passage read by the clinical provider, completed an auditory passage comprehension task, and self-rated their effort as a part of the larger study. Measures of electrodermal activity and blood volume pulse amplitude were collected from the child E4 wristband. No differences in child subjective, physiological measures of LE or passage comprehension scores were found between in-person sessions and telesessions. However, an effect of treatment duration on subjective and physiological measures of LE was identified. Children self-reported a significant increase in LE over time. However, their physiological measures demonstrated a trend indicating a decrease in LE. A significant association between subjective measures and the passage comprehension task was found suggesting that those children who reported more effort demonstrated a higher proportion of correct responses. The study demonstrated the feasibility of collection of physiological measures of LE in NH children during remote and in-person communication using the E4 wristband. The results suggest that measures of LE are multidimensional and may reflect different sources of, or cognitive responses to, increased listening demand. https://doi.org/10.23641/asha.27122064.

Effects of epileptic seizures on the quality of biosignals recorded from wearables.

Wearable nonelectroencephalographic biosignal recordings captured from the wrist offer enormous potential for seizure monitoring. However, signal quality remains a challenging factor affecting data reliability. Models trained for seizure detection depend on the quality of recordings in peri-ictal periods in performing a feature-based separation of ictal periods from interictal periods. Thus, this study aims to investigate the effect of epileptic seizures on signal quality, ensuring accurate and reliable monitoring. This study assesses the signal quality of wearable data during peri-ictal phases of generalized tonic-clonic and focal to bilateral tonic-clonic seizures (TCS), focal motor seizures (FMS), and focal nonmotor seizures (FNMS). We evaluated accelerometer (ACC) activity and the signal quality of electrodermal activity (EDA) and blood volume pulse (BVP) data. Additionally, we analyzed the influence of peri-ictal movements as assessed by ACC (ACC activity) on signal quality and examined intraictal subphases of focal to bilateral TCS. We analyzed 386 seizures from 111 individuals in three international epilepsy monitoring units. BVP signal quality and ACC activity levels differed between all seizure types. We found the largest decrease in BVP signal quality and increase in ACC activity when comparing the ictal phase to the pre- and postictal phases for TCS. Additionally, ACC activity was strongly negatively correlated with BVP signal quality for TCS and FMS, and weakly for FNMS. Intraictal analysis revealed that tonic and clonic subphases have the lowest BVP signal quality and the highest ACC activity. Motor elements of seizures significantly impair BVP signal quality, but do not have significant effect on EDA signal quality, as assessed by wrist-worn wearables. The results underscore the importance of signal quality assessment methods and careful selection of robust modalities to ensure reliable seizure detection. Future research is needed to explain whether seizure detection models' decisions are based on signal responses induced by physiological processes as opposed to artifacts.

Estimation of transpulmonary driving pressure using a lower assist maneuver (LAM) during synchronized ventilation in patients with acute respiratory failure: a physiological study

BackgroundWe previously showed in animals that transpulmonary driving pressure (PL) can be estimated during Neurally Adjusted Ventilatory Assist (NAVA) and Neural Pressure Support (NPS) using a single lower assist maneuver (LAM). The aim of this study was to test the LAM-based estimate of PL (PL_LAM) in patients with acute respiratory failure.MethodsThis was a prospective, physiological, and interventional study in intubated patients with acute respiratory failure. During both NAVA and simulated NPS (high and low levels of assist), a LAM was performed every 3 min by manually reducing the assist to zero for one single breath (by default, ventilator still provides 2 cmH2O). Following NAVA and NPSSIM periods, patients were sedated and passively ventilated in volume control and pressure control ventilation, to obtain PL during controlled mechanical ventilation (PL_CMV). PL using an esophageal balloon (PL_Pes) was also compared to PL_LAM and PL_CMV. We measured diaphragm electrical activity (Edi), ventilator pressure (PVent), esophageal pressure (Pes) and tidal volume. PL_LAM and PL_Pes were compared to themselves, and to PL_CMV for matching flows and volumes.ResultsTen patients were included in the study. For the group, PL_LAM was closely similar to PL_CMV, with a high correlation (R2 = 0.88). Bland–Altman analysis revealed a low Bias of 0.28 cmH2O, and 1.96SD of 5.26 cmH2O. PL_LAM vs PL_Pes were also tightly related (R2 = 0.77).ConclusionThis physiological study in patients confirms our previous pre-clinical data that PL_LAM is as good an estimate as PL_Pes to determine PL, in spontaneously breathing patients on assisted mechanical ventilation.Trial registration The study was registered at clinicaltrials.gov (ID NCT05378802) on November 6, 2021

Enzymatic Activity of Lactoperoxidase in the Colostrum of Cows in different lactations

In order to evaluate the activity of the lactoperoxidase enzyme (LPO), in colostrum and milk at the first month of lactation, the characterization of colostrum in cows was carried out from the first day postpartum and during the first month of lactation, in first, second, third and more lactations for six (06) months, the parameters were analyzed: acidity, pH, temperature, qualitative detection of the lactoperoxidase enzyme, quantifying the volume of the LPO activity. Descriptive statistics were applied using the STATISTIX 4.0 package (1985-1992) and one-way nonparametric statistics Kruskal – Wallis test for the levels First, second, third and more lactations and for the characterized parameters, using the SAS-STAT statistical system, to know the independence of the variables under study. It was found that the acidity is high and varies in a decreasing manner as follows: 37.68; 27.13 and 26.13 ml of NaOH O.1N/100ml. respectively, the pH was observed below that of milk, ranging between 5.0 and 6.2 (equiv/L). The enzymatic activity registered values of up to 182.89 U/lt., considered low compared to milk in the first month of lactation; from one to more than three lactations, according to the values found: 383.9, 394.39 and 753.54 U/ml respectively. It is concluded that the enzymatic activity is low in colostrum and then increases, until reaching the values of normal milk in the first month of lactation. The independence of each parameter (variable) in colostrum was also verified.

Tactile stimulation designs adapted to clinical settings result in reliable fMRI-based somatosensory digit maps

Movement constraints in stroke survivors are often accompanied by additional impairments in related somatosensory perception. A complex interplay between the primary somatosensory and motor cortices is essential for adequate and precise movements. This necessitates investigating the role of the primary somatosensory cortex in movement deficits of stroke survivors. The first step towards this goal could be a fast and reliable functional Magnetic Resonance Imaging (fMRI)-based mapping of the somatosensory cortex applicable for clinical settings. Here, we compare two 3 T fMRI-based somatosensory digit mapping techniques adapted for clinical usage in seven neurotypical volunteers and two sessions, to assess their validity and retest-reliability. Both, the traveling wave and the blocked design approach resulted in complete digit maps in both sessions of all participants, showing the expected layout. Similarly, no evidence for differences in the volume of activation, nor the activation overlap between neighboring activations could be detected, indicating the general feasibility of the clinical adaptation and their validity. Retest-reliability, indicated by the Dice coefficient, exhibited reasonable values for the spatial correspondence of single digit activations across sessions, but low values for the spatial correspondence of the area of overlap between neighboring digits across sessions. Parameters describing the location of the single digit activations exhibited very high correlations across sessions, while activation volume and overlap only exhibited medium to low correlations. The feasibility and high retest-reliabilities for the parameters describing the location of the single digit activations are promising concerning the implementation into a clinical context to supplement diagnosis and treatment stratification in upper limb stroke patients.

Predictive modeling of sensory responses in deep brain stimulation.

Although stimulation-induced sensations are typically considered undesirable side effects in clinical DBS therapy, there are emerging scenarios, such as computer-brain interface applications, where these sensations may be intentionally created. The selection of stimulation parameters, whether to avoid or induce sensations, is a challenging task due to the vast parameter space involved. This study aims to streamline DBS parameter selection by employing a machine learning model to predict the occurrence and somatic location of paresthesias in response to thalamic DBS. We used a dataset comprising 3,359 paresthetic sensations collected from 18 thalamic DBS leads from 10 individuals in two clinical centers. For each stimulation, we modeled the Volume of Tissue Activation (VTA). We then used the stimulation parameters and the VTA information to train a machine learning model to predict the occurrence of sensations and their corresponding somatic areas. Our results show fair to substantial agreement with ground truth in predicting the presence and somatic location of DBS-evoked paresthesias, with Kappa values ranging from 0.31 to 0.72. We observed comparable performance in predicting the presence of paresthesias for both seen and unseen cases (Kappa 0.72 vs. 0.60). However, Kappa agreement for predicting specific somatic locations was significantly lower for unseen cases (0.53 vs. 0.31). The results suggest that machine learning can potentially be used to optimize DBS parameter selection, leading to faster and more efficient postoperative management. Outcome predictions may be used to guide clinical DBS programming or tuning of DBS based computer-brain interfaces.

Modeling Reversible Volume Change in Automotive Battery Cells with Porous Silicon Oxide-Graphite Composite Anodes

Automotive battery manufacturers are working to improve the individual cell and overall pack design by increasing durability, performance, and range, while reducing cost, and active material volume change is a key aspect that needs to be considered during this design process. Recently, silicon oxide-graphite composite anodes are being explored to increase total anode capacity while maintaining a tolerable amount of cell level reversible volume expansion due to the relatively lower reversible volume change of the silicon oxide compared to pure battery grade or metallurgical grade silicon. To predict the blended anode response and contribution to the overall cell volume change, we integrated the mechanical behavior of the individual active materials with the multi-species, multi-reaction model to predict the state-of-lithiation of the active materials in the cell at a given potential. The resulting simulations illustrate the tradeoff in volume change between the silicon oxide and the graphite during cell operation. This type of modeling approach will allow designers to virtually consider the impact of cell level and pack level design changes on overall system mechanical performance for automotive and grid storage applications, namely that relatively small addition of silicon containing materials can drive a significant increase in the volume change at the cell level, as demonstrated by the 5 wt% addition of silicon oxide accounting for half of the overall volume change in the cell.

Next-generation monitoring in obstetrics: Assessing the accuracy of non-piezo portable ultrasound technology.

The emergence of handheld ultrasound devices capable of connecting to cell phones or tablets heralds a significant advancement in medical technology, particularly within the field of obstetrics. These devices offer the promise of immediate bedside ultrasound examinations, potentially revolutionizing patient care by enabling fetal assessments in diverse settings. This prospective study aimed to validate the reliability of non-piezo, chip-based handheld ultrasound devices in clinical obstetric practice. Conducted in a university hospital obstetric ward, the study included 100 pregnant women between 17 and 41 weeks of gestation. Participants underwent ultrasound examinations using both conventional and portable point-of-care ultrasound (POCUS) devices to compare the accuracy in estimating fetal weight and other parameters, such as cardiac activity, fetal presentation, placental location, and amniotic fluid volume. The reliability and agreement between the devices were assessed using intraclass correlation coefficients, Bland-Altman plots, and Pearson correlation coefficients. The results show a near-perfect agreement (0.98) and correlation (r = 0.98, p < 0.001) for estimated fetal weight and most biometry measurements between the two types of ultrasound devices, with slight deviations in head circumference and amniotic fluid index measurements. Subgroup analysis revealed variations in agreement and correlation rates with higher BMI and advanced gestational age, indicating areas for further refinement. These findings affirm the high reliability of handheld ultrasound devices for basic obstetric ultrasound evaluations, supporting their integration into daily clinical practice. This technology improves the flexibility and immediacy of prenatal care, although further research is needed to optimize its application across patient populations and treatment settings.

Microstructure evolution by thermomechanical processing and high-temperature mechanical properties of HCP-high entropy alloys (HEAs)

The solid solution strengthening and deformation mechanisms of the hcp-high entropy alloys (HEAs) have not been elucidated yet because of the complexity introduced by the martensite structure, particularly in alloys undergoing phase transformation from bcc to hcp structures. This study attempted to fabricate an equiaxed hcp microstructure for TiZrHf, TiZrHfAl, and TiZrHfAlSc using the hot rolling process and subsequent heat treatment. The equiaxed hcp phase was successfully formed in TiZrHfAl, but the martensite structure remained in TiZrHf and TiZrHfAlSc. The 0.2 % proof stress at 400 and 600°C increased with the increase of the average atomic size misfit δ and the mixing entropy . The low activation volume and high-stress exponent of TiZrHfAl with equiaxed hcp phase at room temperature suggest minor obstacles such as cluster or short-range order inhibit the movement of dislocation and leading to the significant solid-solution strengthening. However, the effect diminished at 600 °C.

Comment on “physical activity volume, intensity and life expectancy”

Comment on “physical activity volume, intensity and life expectancy”

How do urban block built environments affect older adults' walking activities and health effects: a case study in Nanjing, China.

Research on the relationship between microscale built environments and physical activity among older adults in densely populated old urban areas with high aging rates is scarce. Particularly, the relationship between urban block land-use pattern and older adults' walking activities have not yet been completely understood. This study examined the daily walking habits and socioeconomic attributes of older adults in 17 blocks with different built environment characteristics in Nanjing City, China. A multi-layer linear model was used to quantitatively analyse the mechanism underlying the effects of various factors on the health of older adults. The result shows significant positive correlation between neighborhood walkability and the enhancement of walking frequency and activity. For every 10% increase in pedestrian road connectivity and land use, the walking activity volume increased by 22.4 and 12%, and the BMI increased by 9.1 and 7.3% toward the standard range, respectively. For every 10% increase in distance between residence and plaza and park, the walking activity volume decreased by 5.4 and 3.2%, and BMI decreased by 9.9 and 6.3%, respectively. For every 10.4% increase in land mixed-use rate and per capita green area, BMI increased by 19.4%. Furthermore, higher household income and number of family members have significant correlation with walking activities and health effects. Moreover, the block-scale built environment and walking activities jointly affected health, with a cross-functional relationship between multiple factors.

Effect of Er on the Hot Deformation Behavior of the Crossover Al3Zn3Mg3Cu0.2Zr Alloy

The effect of an erbium alloying on the hot deformation behavior of the crossover Al3Zn3Mg3Cu0.2Zr alloy was investigated in detail. First of all, Er increases the solidus temperature of the alloy. This allows hot deformation at a higher temperature. The precipitates resulting from the Er alloying of the Al3Zn3Mg3Cu0.2Zr alloy were analyzed using transmission electron microscopy. Erbium addition to the alloy produces the formation of more stable and fine L12-(Al3(Zr, Er)) precipitates with a size of 20–60 nm. True stress tends to increase with a decline in the temperature and an increase in the deformation rate. The addition of Er leads to decreases in true stress at the strain rates of 0.01–1 s−1 due to particle-stimulated nucleation softening mechanisms. The effective activation energy of the alloy with the Er addition has a lower value, enabling an easier hot deformation process in the alloy with an elevated volume fraction of the intermetallic particles. The addition of Er increases the strain rate sensitivity, which makes the failure during deformation less probable. The investigated alloys have a significant difference in the dependence of the activation volume on the temperature. The flow instability criterion allows better deformability of Er-doped alloys and enables the alloys to be formed more easily. The evenly distributed particles prevent the formation of shear bands with elevated storage energy and decrease the probability of crack initiation during the initial stages of hot deformation when only one softening mechanism (dynamic recovery) is working. The microstructure analysis proves that dynamic recovery is the main softening mechanism.