Time Stability Research Articles

The effect of juggling on the proprioceptive and attentional abilities among older women.

Age-related changes in attentional abilities can lead to a decline in body segment awareness in space. However, studies have reported that physical activity can improve proprioception among older adults, although proven activities with this potential are limited. Juggling is a promising activity for enhancing proprioception, as it requires high levels of attention and sensory precision. The first hypothesis posited that a juggling intervention would positively impact ipsilateral and contralateral elbow joint position matching without visual input. The second hypothesis suggested a correlation between cognitive abilities and joint position sense efficiency. A total of 20 older women (mean age: 69.95 ± 4.58) participated in a repeated-measures study using a Latin square design. Measurements were taken at three time points (baseline, post-juggling, and control). Ipsilateral and contralateral elbow joint position matchings without visual or verbal feedback of accuracy were used to assess proprioception. Attention and reaction time variables were measured using the Vienna Test System protocols. Although significant changes were observed between baseline and subsequent time points in joint position sense accuracy, no specific effect of juggling was detected. Low and medium correlations were found between decision time and the variability of choice reaction time with contralateral accuracy. For ipsilateral accuracy, a relationship was observed only with handedness. No correlations were found between attention test scores and joint position sense accuracy. The study did not demonstrate a significant effect of juggling on position-matching ability. However, cognitive abilities such as decision speed and the stability of choice reaction time may play a role in enhancing position-matching in older women. ClinicalTrials.gov, identifier NCT06108713.

Efficient Formaldehyde Gas Sensing Performance via Promotion of Oxygen Vacancy on In-Doped LaFeO3 Nanofibers.

Perovskite oxide LaFeO3(LFO) emerges as a potential candidate for formaldehyde (HCHO) detection due to its exceptional electrical conductivity and abundant active metal sites. However, the sensitivity of the LFO sensor needs to be further enhanced. Herein, a series of LaxIn1-xFeO3 (x = 1.0, 0.9, 0.8, and 0.7) nanofibers (LxIn1-xFO NFs) with different ratios of La/In were obtained via the electrospinning method followed by a calcination process. Among all these LxIn1-xFO NFs sensors, the sensor based on the L0.8In0.2FO NFs possessed the maximum response value of 18.8 to 100 ppm HCHO at the operating temperature of 180 °C, which was 4.47 times higher than that based on pristine LFO NFs (4.2). Furthermore, the L0.8In0.2FO NFs sensor also exhibited a rapid response/recovery time (2 s/22 s), exceptional repeatability, and long-term stability. This excellent gas sensing performance of the L0.8In0.2FO NFs can be attributed to the large number of oxygen vacancies induced by the replacement of the A-site La3+ by In3+, the large specific surface area, and the porous structure. This research presents an approach to enhance the HCHO gas sensing capabilities by adjusting the introduced oxygen vacancies through the doping of A-sites in perovskite oxides.

A-150 Extended Pre-Analytical Stability Validation for Coagulation Tests in Brazilian Clinical Laboratory

Abstract Background The transport of samples for coagulation tests is a challenge for clinical laboratories, due to their limited stability and short time for processing according to the manufacturer's recommendations. The objective of this study was to evaluate the possibility of extending the stability of samples collected for Prothrombin Time and Activity (PTA), activated Partial Thromboplastin Time (aPTT) and Fibrinogen tests for up to 10 hours at room temperature, in comparison with the stability described in the literature and by the manufacturer of the reagents (4 hours for aPTT, 8 hours for PTA and Fibrinogen). We verified the acceptability of the samples with a longer period between collection and analysis, including its impact on the clinical management Methods Four tubes of 3.2% sodium citrate from 40 volunteers were analyzed at times of up to 4 h, 6 h, 8 h and 10 h. The results obtained were compared with the dosage performed within 4 hours (recommended by manufacturer) and the Total Error obtained in the analysis of the samples was evaluated. The tubes remained at controlled room temperature of 15 to 25°C and were centrifuged at 1500 g for 15 minutes. Then, the analyses were performed by coagulometric method. Results The results showed safety in the analysis of samples for coagulation tests even within 10 hours after collection at ambient temperature and were within the Maximum Allowable Total Error (Carmen Ricós): 95% of the PTA results (TE 5,3%); 92.2% of aPTT results (TE 4,5%) and 98% of Fibrinogen analyses (TE 13,6%) (Figures 1, 2 and 3). In addition, even the results that exceeded the specified Total Error showed no impact on the clinical decision. Conclusions The study demonstrated that there was no significant loss of stability for the analyses of PTA, aPTT and Fibrinogen performed on samples kept at room temperature within 10 hours after collection. Most of the results showed variation within the specified Total Error and all results showed acceptability from a medical point of view

B-018 Design and Development of MASTM Diabetes Max Controls, Ready-to-Use Plastic Tube Format

Abstract Background The Thermo Scientific™ MAS™ Controls are assayed controls to monitor assay performance within clinical laboratory settings. The user can compare observed results of controls with their expected ranges as a means of assuring consistent performance of both reagent and instrument. The objective of developing MAS™ Ready-to-Use Tube Controls is to provide MAS™ controls in a new automation-friendly plastic tube format, as an alternative to the current glass vials. Diabetes Max Control is the first MAS™ product designed and developed in this ready-to-use format to be placed directly on the analyzer. The new format will increase efficiency and allow for on-board refrigerated storage, and it is expected to reduce material loss and contamination. It contains Hemoglobin A1c formulated in whole blood matrix to mimic patient specimens. In this presentation we summarize the Feasibility, Development, Verification, and Validation results of MAS™ Diabetes Max Controls. Methods The performance was assessed by conducting the following studies for MAS™ Diabetes Max Tube Controls. The analyte Hemoglobin A1c was measured in functional studies to evaluate and verify the product performance. Other studies were also designed and performed to assess the product usability. Results MAS™ Diabetes Max Control results demonstrated comparable performance and Fit/Form/Function criterion on specified platforms, particularly the TOSOH™ platform. All feasibility studies provided very promising results passing per protocol criterion. Design Verification and Validation studies ensured product integrity and passed specifications for proposed claims. Process Validation is in progress with data being collected for both Value Assignments and Real Time Stability. Conclusions MAS™ Diabetes Max Controls provided in ready-to-use tubes met the design specification criteria. We believe that MAS™ Diabetes Max Controls will contribute to the increased efficiency of core lab workflow by allowing the analyzer(s) to aspirate controls directly from the tube and allow for control storage in an on-board refrigeration unit.

A-127 Stability of Ionized Calcium in Blood Gas Specimens

Abstract Background Ionized calcium monitoring is crucial for monitoring critically ill patients as well as patients undergoing apheresis. According to CLSI C31-A2:2001, the acceptable stability time for all tests to be run on blood gas analyzers in heparinized syringes is thirty minutes from collection. We sought to determine whether the stability of ionized calcium in blood gas samples can be extended to accommodate prolonged transport times. Methods Sixty whole blood samples were collected into 1CC syringes containing 23 IU of heparin (Vital Signs, Inc.) and sent to the laboratory for ionized calcium and pH analysis on the Siemens RAPIDLab 1265. If the remaining sample was sufficient, it was set aside for additional testing 40, 60 and 90 minutes after receipt in the laboratory. All samples were kept at room temperature during all timepoints. The three timepoints were compared to the initial reported baseline result and the average percent bias and standard deviation was determined. Results When compared to the baseline result, samples analyzed at the 40-, 60-, and 90-minute timepoints showed negligible bias for both pH and ionized calcium. The absolute bias was within +/- 0.6 and +/-0.4 for ionized calcium and pH, respectively. Conclusions This study showed that accurate measurements of both ionized calcium and pH can be obtained from blood gas samples collected in heparinized syringes at least till 90 minutes after collection.

Using higher rates of stabilization of a wet-spun pan fibre to understand the effect of microstructure on the tensile and compressive properties of carbon fibre

The transformation of a polyacrylonitrile (PAN) precursor fibre into carbon fibre using varying stabilization times during carbon fibre manufacture is presented in this work. The wet-spun precursor fibre is a specifically designed PAN co-polymer made up of acrylonitrile, methyl acrylate and 3 wt% itaconic acid. The residence or stabilization times in the oxidation ovens are varied from 32, 64 and 96 min, enabling investigation of the impact upon microstructure upon tensile and compressive properties. Using a continuous pilot scale carbonization line for faster cyclization and dehydrogenation, the precursor fibres exhibited lower oxygen uptake contributing to the formation of a less dense and more amorphous carbon fibre. Synchrotron based SAXS-WAXS characterisation and Raman spectroscopy of the carbon fibre microstructure displays lower orientation and crystallinity, with higher void concentration. This led to lower electrical conductivity, lower tensile strength (19 %) but higher compressive strength (27 %) when reducing stabilisation times from 96 to 32 min.

Ultrathin natural biotite crystals as a dielectric layer for van der Waals heterostructure applications

Biotite, an iron-rich mineral belonging to the trioctahedral mica group, is a naturally abundant layered material (LM) exhibiting attractive electronic properties for application in nanodevices. Biotite stands out as a non-degradable LM under ambient conditions, featuring high-quality basal cleavage-a significant advantage for van der Waals heterostructure (vdWH) applications. In this work, we present the micro-mechanical exfoliation of biotite down to monolayers (1Ls), yielding ultrathin flakes with large areas and atomically flat surfaces. To identify and characterize the mineral, we conducted a multi-elemental analysis of biotite using energy-dispersive spectroscopy mapping. Additionally, synchrotron x-ray fluorescence and infrared nano-spectroscopy were employed to probe its iron content and vibrational signature in few-layer form, respectively, with sensitivity to the layer number. We have also observed good morphological and structural stability in time (up to 12 months) and no important changes in their physical properties after thermal annealing processes in ultrathin biotite flakes. Conductive atomic force microscopy evaluated its electrical capacity, revealing an electrical breakdown strength of approximately 1 V nm-1. Finally, we explore the use of biotite as a substrate and encapsulating LM in vdWH applications. We have performed optical and magneto-optical measurements at low temperatures. We find that ultrathin biotite flakes work as a good substrate for 1L-MoSe2, comparable to hexagonal boron nitride flakes, but it induces a small change of the 1L-MoSe2g-factor values, most likely due to natural impurities on its crystal structure. Furthermore, our results show that biotite flakes are useful systems to protect sensitive LMs such as black phosphorus from degradation for up to 60 days in ambient air. Our study introduces biotite as a promising, cost-effective LM for the advancement of future ultrathin nanotechnologies.

Exploring the impact of selenium-enriched peptides from yeast autolysate on dough properties: Insights into mechanisms from gluten perspectives

This study investigated the impact of Selenium (Se)-enriched yeast autolytic peptides (SeYAP) with different Se levels on dough properties as well as the related mechanism by focusing on gluten. SeYAP prolonged the dough's development time by up to 131 % and stability time by up to 28 %. It also decreased dough's viscoelasticity and rendered dough softer. Additionally, SeYAP diminished the binding capacity of dough to water and augmented the fluidity of water. Protein composition, disulfide bonds and fluorescence spectroscopy revealed that SeYAP could induce depolymerization of glutenin aggregate through sulfhydryl/disulfide bond exchange and hydrophobic interactions. Seven Se-enriched peptides were identified from the fraction with strong ability to depolymerize gluten. Specifically, six peptides contained selenocysteine, while another peptide contained selenomethionine. Molecular docking indicated that Se-enriched peptides could interact with amino acids (such as glutamine, tyrosine and proline) in gluten via hydrophobic interactions and/or hydrogen bonds.

Ammonia Gas Sensing Using Porous silicon

Abstract Psi prepared by Electrochemical etching technique at invariable etching current density of 10 mA/cm2 and at different times (7 and 17) min. The porous Si structure was studied using XRD, (FE-SEM) and EDS. The process of sensing NH3 gas is carried out at different operating temperatures (R.t,80,130 and 200)°C and the gas concentration is constant. It is measured by changing the resistance of the sensor as a function of exposure time to the gas. The result showed the XRD patterns of the PS at (7 and 17) min etching time. the peak samples at (111) around 2θ = 28.5°. It is observed that the peak intensity declines with rising the etching time, and some structural parameters for porous silicon are calculated. From FE-SEM, the images show the sample prepared in (7 and 17) min with the depth of (6.18 12.82) μm, with a size of about 50 nm. Porous silicon that was produced in a time of 17 min has a higher sensitivity to NH3 gas than that of the sample that was produced in a time of 7 min. It was found that when the operating temperature changes from (R.T -200C°), the sensitivity of the samples changes with the stability of the etching time. The PSi sample (17 min) has a high sensitivity for NH3 gas at room temp.

LEO satellite clock modeling and its benefits for real-time LEO PPP timing

In the kinematic Precise Orbit Determination (POD) process for low earth orbit (LEO) satellites, a significant correlation exists between the orbital and clock parameters. Here, a LEO satellite clock model is proposed to enhance the Precise Point positioning (PPP) timing and time synchronization during the LEO orbit/clock determination. The GRACE-FO satellite was utilized to achieve PPP timing and time transfer for LEO satellites with the real-time (RT) products provided by three analysis centers, namely Centre National d’Etudes Spatiales (CNES), GMV Aerospace and Defense (GMV), and Wuhan Technical University (WHU). For the frequency stability of the PPP timing for LEO satellites, the short-term stability (1280 s) is about 10−13 level, and the long-term stability (10,240 s) is about 10−14 level. Compared with the traditional PPP method (Scheme1), the LEO satellite clock model (Scheme2) is capable of significantly reducing the noise, regardless of whether it is PPP timing or PPP time synchronization. The frequency stability of Scheme 1 shows an improvement in short-term stability (1280 s) by about 8 %-72 % and the max improvement of the long-term stability (10240 s) by approximately 39 %, the result also shows a better improvement in LEO time synchronization.

Soil urease functional stability to Hg pollution: An ecotoxicological perspective.

Mercury (Hg) is a persistent soil pollutant, and its toxicity can be evaluated using soil enzyme indicators. However, a thorough understanding of how the enzyme resists and remains resilient to Hg stress is essential, as it significantly impacts the accuracy of toxicity assessments. Therefore, it is worthwhile to understand the functional stability of urease in soil under Hg pollution. This study compares the effects of Hg at different concentrations and exposure times on soil urease. Results indicate that soil urease activity was enhanced in the first two hours under low levels of Hg pollution, decreased after six hours of acute Hg pollution, and reached its maximum reduction in 24 hours. The urease in fluvo-aquic soil, with higher soil organic matter showed higher resistance to Hg acute pollution than that in red soil. Over a longer aging process, soil urease activity gradually recovered with time. Hormesis effects were observed in red soil under high Hg stress after 30 days, showing the strong resilience of urease enzyme function to Hg pollution. The ecological dose, ED10, (the Hg concentration causing a 10% reduction in soil urease activity) ranged from 0.09 to 0.59 mg kg-1 under short-term exposure, and was lower than that under a longer aging process (0.28 to 2.71 mg kg-1). Further, aging reduced the Hg ecotoxicity due to decreased Hg availability and the resilience of soil urease activity. This indicates that the risk of Hg pollution estimated by soil urease as an indicator depends on exposure time and enzyme stability. These factors need consideration in heavy metal pollution assessments using soil enzymes.

Real-time adaptive model of mainstream parameters for aircraft engines based on OSELM-EKF

Gas path parameters play a crucial role in the health management of aeroengines, which are usually generated from the nonlinear component-level model. However, risks of stability and substantial time consumption confine online applications of conventional models. This paper proposes a mainstream parameter model that exclusively involves rotating components using fewer gas path parameters, including an adaptive strategy based on an online sequential extreme learning machine and an extended Kalman filter. The mainstream parameter model is designed in a linear parameter-varying form with a non-iterative smooth state-switching mechanism and enables real-time operation by simplifying the component complexity. Besides, some sensor measurements are employed to update rotor speeds, thus eliminating the need for derivative computations. Neural networks are introduced in compressor component calculations. Additionally, the extended Kalman filter is developed to estimate health parameters to tune the system equation residuals, and the learning machine is applied to compensate for rotating components’ pressure ratios under different degradation magnitudes. Finally, systematic tests are carried out to evaluate the computation accuracy and fast capabilities of the mainstream parameter adaptive model in various scenarios. Simulations demonstrate the proposed methodology's superiority over traditional adaptive correction schemes.

Post-Concussion Sleep Quality Association With Dual-Task Postural Stability, Cognition, And Reaction Time Among Adolescents

Post-Concussion Sleep Quality Association With Dual-Task Postural Stability, Cognition, And Reaction Time Among Adolescents

Influence of residual stress on the high-temperature tribological performance of nickel-based superalloy

This study introduces a method for generating residual compressive stress by utilizing differences in thermal expansion coefficients of materials. A corresponding experimental device has been developed. Using this method, experiments were conducted to investigate the effects of residual compressive stress on the tribological properties of the nickel-based superalloy Ni16Cr13Co4Mo. The results indicate that residual stress significantly affects the friction behavior and wear resistance of the superalloy. The stabilization time of the friction coefficient as well as the wear rate reaches a minimum under moderate residual compressive stresses. Moderate residual compressive stress can facilitate the formation of a tribo-oxide layer and enhance its bonding strength with the substrate, thereby shortening the time for stabilization of the friction coefficient and reducing the wear rate. Finite element simulation of static ball-on-disc contact model also shows that residual stress alters the internal stress distribution inside the alloy, and changes its yield and plastic behavior. Under moderate residual compressive stress, a reduction in maximum von Mises stress can be achieved, which is consistent with the variation rule of friction coefficient and wear rate in the tests.

Implementing a two-stage, shim field-calibrated superconducting shimming method on a 7 T cryogen-free small animal MRI magnet

Ultrahigh field systems (≥ 7 T) can increase the signal-to-noise ratio of magnetic resonance imaging (MRI), improving imaging performance compared to systems with lower fields. However, these enhancements heavily rely on a high B0 magnetic field homogeneity level, which can be achieved through superconducting shimming. This paper presents a novel two-stage superconducting shimming method designed to achieve precise shimming for a 7 T MRI superconducting magnet. In the initial stage, detailed measurements and fittings were conducted to determine the current polarity and the axial or circumferential positions of the shim fields. Subsequently, an optimization strategy was implemented to determine the optimal shim currents with a flexible target field. The second stage involves an iterative process to fine-tune the current of a specific shim coil, identified as having the most significant impact on field homogeneity. The overall fitness of 99.5% underscores the precision in determining the current polarity and position of the shim fields. Significantly, the calibrated shim system substantially improves the peak-to-peak and Root Mean Square Error (RMSE) field homogeneities from 107.42 ppm and 37.00 ppm to 11.12 ppm and 3.26 ppm, respectively, representing improvements of 89.65% and 91.19%. Furthermore, the simulation results of the fine-tuning stage demonstrate additional enhancements in peak-to-peak field homogeneity, to 9.9 ppm by reducing the current of the Z2 shim coil by 51.3 mA. Additionally, the shimmed magnetic field exhibited high time stability, with a maximum variation of only 27 µT observed within 48 h. Thus, the proposed two-stage superconducting shimming framework effectively addresses the challenge of imperfect B0 magnetic fields, enhancing peak-to-peak and RMSE field homogeneity. The stepwise optimized approach also mitigates deviations caused by shim-to-shim coupling, demonstrating its efficacy in achieving precise shimming in ultrahigh-field MRI systems.

Adaptive Fuzzy Predefined-Time Synchronization of Different Dimensional Delayed Chaotic Systems: A Scheme for Realizing Predefined Time Stability of Nonlinear Systems

Adaptive Fuzzy Predefined-Time Synchronization of Different Dimensional Delayed Chaotic Systems: A Scheme for Realizing Predefined Time Stability of Nonlinear Systems

Atmospheric Pressure Portable Catalytic Thermal Plasma System for Fast Synthesis of Aqueous NO3 and NO2 Fertilizer from Air and Water

AbstractMeaningful deployment of plasma water-based nitrogen fixation in agricultural application is hindered primarily due to its poor synthesis rate in compact systems. The study reports a directly deployable thermal plasma based portable catalytic compact system, offering typical synthesis rate as high as 1035 mg/min for nitrate and 635 mg/min for nitrite directly from naturally abundant atmospheric air and water. Developed technology is clean, sustainable, easily decentralizable, and completely free from fossil fuels and harmful intermediates like ammonia. The system avoids safety hazards and costs related to the requirements of continuous energy resources, pressurized environment for synthesis, regulated storage, refrigeration need, transportation of raw materials and distribution of fertilizer, as may be required by other competing technologies. Described system, consisting of air plasma torch, reaction chamber, water injection manifold and catalytic bed creates a unique nascent reactive plasma environment at ambient pressure that auto activates the catalyst in the field of thermal plasma for highly efficient fixation of nitrogen. Presented results indicate that use of combination catalysts with mechanically enhanced surface area allows drastic enhancement in the nitrogen fixation. Possible reaction chemistries, results of trials with different catalysts, time evolution of concentration, auto-conversion from nitrite to nitrate in aqueous media, time stability of concentration of the synthesized nitrate and observed remarkable effectiveness in the actual field trials are presented. Achieved synthesis rates are compared with those reported in literature in the area of thermal and non-thermal plasma.

Experiment and dynamic simulation of micro gas turbine combined with concentrated solar power system

The solar micro gas turbine (SMGT) system is a promising solution to address the instability and intermittency of renewable energy sources. Its dynamic characteristics under unstable input conditions and uncertain output load demands are crucial for peak shaving. This paper constructs an SMGT system based on experiments with micro gas turbine (MGT) and concentrated solar power (CSP), analyzing the impact of integrating CSP system on the MGT. Then the performance of the SMGT under varying ambient conditions and load demands is studied. Results show that in grid-connected mode, the turbine speed of MGT and SMGT is determined by ambient temperature and set power, with electrical efficiency decreasing as temperature and DNI increase. The solar receiver in the SMGT should maximize temperature increase while maintaining pressure loss below 55 kPa. Additionally, a higher heat capacity can reduce sensitivity to ambient changes but also extends stabilization time. Under real solar radiation, the SMGT system can keep constant power within 0.6% fluctuation, with a solar share of 36.5%. When combined with photovoltaic, the hybrid system’s maximum power fluctuation does not exceed 2.6%, with a solar share of 48.8%. This study provides guidance for optimizing SMGT systems and their application in peak shaving scenarios.

Influence of collapsible shape of Loess Foundation on high-speed railway subgrade under train vibration loading

Collapsible loess has special sensitivity to water, and its engineering mechanical properties deteriorate significantly after immersion in water, causing the foundation to sink, which seriously threatens the safety and stability of the high-speed railway subgrade under train vibration loading. Studying this effect is essential to prevent and control the disasters of high-speed railway subgrades. In this study, a model with the function of simulating foundation settlement is established to conduct disaster testing of high railway subgrade under train vibration loading. The results indicate that when different foundation shapes are settled, the surface of the subgrade under static load is gradually settled in a short time, and the settlement value of the track surface is lower than that of the corresponding subgrade surface. Under train vibration load, the maximum dynamic settlement occurs at the middle of the subgrade slope, which is smaller than the corresponding settlement under static load. The number of stabilization times required from different monitoring positions on the subgrade surface is different under different excitation forces, and the number of stabilization times required is more in the middle of the subgrade slope and the slope shoulder. The influence of train speed on subgrade has a critical respond speed that increases with increasing vibration times. There are horizontal, vertical and 45° angle cracks in the middle of subgrade slope. It is qualitatively assessed that the slope of the high-speed railway subgrade in the collapsible loess area is unstable under the effect of train load. The data and rules provided in this document provide some reference values for the construction of a high-speed railway in the collapsible loess area.

Volatility Index, Exchange Rate, Economic Growth On Stock Indexes

This study aims to analyse the effect of economic growth on the stock price index in Indonesia and Malaysia during the COVID-19 pandemic. Using regression analysis, this study measures the relationship between economic growth and the stock price index, focusing on both countries' fiscal and monetary policies. The results show that economic growth has a positive and significant effect on the stock price index in Indonesia and Malaysia, reflecting investors' optimism towards the economic outlook. Economic stimulus policies and monetary measures the government and central bank take are essential in supporting economic recovery and stock market stability. This research provides important insights for investors in making more informed investment decisions based on economic growth indicators. This study also emphasises the importance of responsive and coordinated economic policies to support economic growth and stock market stability in times of crisis.