Test Device Research Articles

Real-world smartphone-based point-of-care diagnostics in primary health care to monitor HbA1c levels in people with diabetes

Abstract Background The lack of accurate and affordable monitoring of glycated hemoglobin (HbA1c) is a common issue among patients with diabetes in low- and middle-income countries. We aimed to test a tablet- and smartphone-based point-of-care (TSB POC) device against a local laboratory-based measure of HbA1c for monitoring diabetes under real-world conditions. Methods For this cross-sectional clinical method applicability study, capillary and venous blood was collected in duplicate and analyzed at local primary health care centers. For a heterogeneity test, the tests were performed by an expert, and by a team of local nurses. The study was conducted in a multicenter design in rural and urban Aceh, Indonesia in 2019, and included a total of 533 adults. We mainly used Bland-Altman plots to assess the number of readings within the 95%-limits of agreement (LoA) and Deming regressions. Results The results show a mean difference between capillary HbA1c on the test device and the reference method of −0.54 [CI0.95 = −1.6933; 0.6048] with 5.21% of measurements outside the LoA and a Pearson’s r = 0.91 in the Deming Regression. There is no significant difference in test concordance between local nurses and the expert (4.23% versus 5.13% results outside the LoA [CI0.95 = −0.0331; 0.0511]). Conclusions TSB POC for analysis of HbA1c is an acceptable alternative for accessible monitoring of diabetes patients under these conditions. This method could provide access to high-quality diagnostic decisions through regular and cost-effective HbA1c monitoring directly in healthcare facilities, thus providing better access to essential health services.

A Novel Model for Noninvasive Haemoglobin Detection Based on Visibility Network and Clustering Network for Multi-Wavelength PPG Signals

Non-invasive haemoglobin (Hb) testing devices enable large-scale haemoglobin screening, but their accuracy is not comparable to traditional blood tests. To this end, this paper aims to design a non-invasive haemoglobin testing device and propose a classification-regression prediction framework for non-invasive testing of haemoglobin using visibility graphs (VG) with network clustering of multi-sample pulse-wave-weighted undirected graphs as the features to optimize the detection accuracy of non-invasive haemoglobin measurements. Different prediction methods were compared by analyzing 608 segments of multiwavelength fingertip PPG signal data from 152 volunteers and analyzing and comparing the data and methods. The results showed that the classification using NVG with complex network clustering as features in the interval classification model was the best, with its classification accuracy (acc) of 93.35% and model accuracy of 88.28%. Among the regression models, the classification regression stack: SVM-Light Gradient Boosting Machine (LGBM) was the most effective, with a Mean Absolute Error (MAE) of 6.67 g/L, a Root Mean Square Error (RMSE) of 8.21 g/L, and an R-Square (R2) of 0.64. The results of this study indicate that the use of complex network technology in non-invasive haemoglobin detection can effectively improve its accuracy, and the detector designed in this study is promising to carry out a more accurate large-scale haemoglobin screening.

Influence of Water Content on Shear Strength and Tangential Adhesion Strength of Sand by a Modified Vane Shear Test Device

Influence of Water Content on Shear Strength and Tangential Adhesion Strength of Sand by a Modified Vane Shear Test Device

Numerical study on inverse grading segregation mechanism of single coarse particles with different particle sizes under two-dimensional cyclic shear

Granular mixtures with size differences can segregate when subjected to shaking or shear. This study investigates the mechanism underlying the inverse grading segregation of single coarse particles with varying sizes under cyclic shear. A self-developed two-dimensional testing device combined with three-dimensional printing technology and the image identification capabilities of the segment anything model enabled the construction of a cyclic shear numerical model based on rigid blocks. The analysis concentrated on the movement of coarse particles and the evolution of the macroscopic structure of the particle system, and the local topological structures surrounding single coarse particles. The findings reveal the following: (1) Larger coarse particle sizes and lower shape factors under cyclic shear result in shorter times to free surface and higher vertical velocities. (2) Throughout the cycles, the vertical net force acting on each coarse particle fluctuates around zero, while its vertical position displays a zigzag upward trend. (3) Within a single typical cycle, larger coarse particles increase the local void ratio, aiding their lift. Vertical displacement and net force exhibit a double peak pattern inversely related to coordination number, while horizontal displacement fluctuates periodically around zero. (4) Weighted local degree centrality negatively correlates with vertical displacement of single coarse particles, reflecting the dual influence of particle size and importance on segregation velocity. Fine particles occupying the two lower corners of single coarse particles create the lifting effect, driving their zigzag upward motion. Additionally, larger coarse particles enhance their importance, accelerating the segregation process.

Physical and mechanical aging of wood-plastic composites. Non-destructive methods for quality control

This study investigates the relationship between laboratory aging, physical and mechanical changes, and the outcomes of non-destructive testing. A total of 45 composite specimens containing 60 % wood fiber, 35 % low-density polyethylene, and 5 % additives were tested. A laboratory aging process, consisting of water immersion at 20 ºC and 50 ºC for a total of 56 days, was applied to the specimens. During the aging process, several batches of specimens were extracted and tested to measure their physical (density) and mechanical properties (bending strength and modulus of elasticity). Non-destructive testing, including ultrasound and stress wave devices, a screw withdrawal resistance meter, and a penetration tester, were employed. Results indicated that temperature had a greater influence on the WPC deterioration than humidity. A decrease in density (2 % - 4 %) and a significant reduction in mechanical properties (20 % - 60 %) were observed. The non-destructive methods used proved to be reliable estimators of composite properties, especially ultrasound wave propagation, confirming previous findings on other materials.

P-2179. Nirsevimab in Patient Samples Does Not Interfere with Respiratory Syncytial Virus (RSV) Detection by Commercially Available Rapid Antigen Tests

Abstract Background Nirsevimab is an extended half-life monoclonal antibody (mAb) that binds to the prefusion conformation of the respiratory syncytial virus (RSV) fusion (F) protein, and is approved for the prevention of RSV-associated lower respiratory tract infection in neonates and infants. Rapid antigen testing is routinely used for the clinical diagnosis of RSV, and primarily relies on direct interaction with the RSV F protein in patient nasal samples. While expected mAb levels in nasal samples are low (< 1 μg/mL), some mAbs targeting the RSV F protein, such as palivizumab, have been shown to interfere with RSV rapid antigen test results. We assessed whether the presence of nirsevimab in samples may interfere with RSV detection by rapid antigen tests, leading to false-negative or equivocal results.Figure 1.Evaluation of nirsevimab- and palivizumab-associated interference with RSV detection by rapid antigen tests Methods We evaluated six waived RSV rapid antigen tests (simple tests with a low risk of erroneous results), representative of those in the US Food and Drug Administration Clinical Laboratory Improvement Amendments database. To assess mAb interference with RSV detection, each test kit was performed according to the manufacture’s procedures (Figure 1). Test samples contained phosphate-buffered saline spiked with RSV subtype A or B at 5 × 105 plaque forming units/mL, and nirsevimab or palivizumab at two concentrations (1 or 10 µg/mL). For RSV-positive results, the intensity of the line on the test device was graded by observers as a ‘weak’ or ‘strong’ RSV detection signal.Table 1.Effects of nirsevimab and palivizumab on RSV detection by a panel of rapid antigen test kits Results RSV was detected by all rapid antigen tests in the presence of nirsevimab at both concentrations, with only a slight decrease in the RSV A detection signal observed for the Remel X/pect RSV kit at concentrations of 10 µg/mL (Table 1). RSV was not detected by the Remel X/pect RSV and Binax NOW RSV kits in samples with 10 µg/mL of palivizumab, and decreases in RSV detection signals were observed for the Quidel QuickVue RSV, Meridian TRU RSV, and BD Directigen EZ RSV kits (Table 1). Funding statement Conclusion Nirsevimab did not interfere with RSV detection for the six RSV rapid antigen tests assessed, even at a high concentration of 10 µg/mL. In contrast, 10 µg/mL of palivizumab did interfere with RSV detection for two test kits. Our findings suggest that patients who have received nirsevimab are unlikely to require alternative assays for clinical RSV diagnosis. Disclosures Sarah R. Sincero, BSc, AstraZeneca: Employee of AstraZeneca and may own AstraZeneca stock or stock options. Katie Streicher, PhD, AstraZeneca: Employee of AstraZeneca and may own AstraZeneca stock or stock options. Elizabeth J Kelly, PhD, AstraZeneca: Former employee of AstraZeneca.|AstraZeneca: Stocks/Bonds (Public Company)|PLP: Stocks/Bonds (Public Company)|Sanofi: Current employee of Sanofi.|Sanofi: Stocks/Bonds (Public Company) Kevin M. Tuffy, MS, AstraZeneca: Employee of AstraZeneca and may own AstraZeneca stock or stock options. Deidre Wilkins, BSC, AstraZeneca: Employee of AstraZeneca and may own AstraZeneca stock or stock options.

Validation of the Pangao PG-800B18 upper-arm blood pressure monitor according to the ISO 81060-2:2018+Amd 1:2020 protocol in the general population.

The study aimed to validate the Pangao PG-800B18 oscillometric upper-arm blood pressure monitor in the general population in accordance with the International Organization for Standardization (ISO) 81060-2:2018 and amendment (Amd) 1:2020 protocol. Participants were recruited, and the same left-arm sequential method was used for blood pressure measurement in accordance with the protocol. Data validation and analysis were performed according to the protocol, and the Bland-Altman scatter plot was used to show the difference between the test device and reference results. A total of 86 participants were included in the validation analysis. For the validation criterion 1 of the protocol, the mean ± SD of the differences between the test device and reference readings was -1.21 ± 6.71 mmHg and -0.73 ± 5.83 mmHg for systolic (SBP) and diastolic blood pressure (DBP), respectively. Furthermore, the SD of the differences between the test device and reference readings per participant was 5.81 and 5.02 mmHg for SBP and DBP, fulfilling the criterion 2 with SD values of ≤6.95 for SBP and ≤5.89 for DBP. The Pangao PG-800B18 upper-arm blood pressure monitor fulfilled the requirements of the ISO validation standard and can be recommended for clinical use and self-measurement in the general population.

The Evolution of Uroflowmetry and Bladder Diary and the Emerging Trend of Using Home Devices From Hospital to Home.

Although uroflowmetry and bladder diaries are widely used for noninvasive evaluation of lower urinary tract symptoms, they still have limitations in diagnostic capability and users' convenience. The aim of this paper is to discuss potential solutions by reviewing (1) the evolution and current clinical use of uroflowmetry and bladder diary, including clinical guidelines, daily practice applications, and their historical development; (2) a growing trend toward using home devices with various technologies; and (3) a comprehensive comparison of the strengths and weaknesses of these home devices. In our opinion, the following points can be highlighted: (1) the emerging trend of using home devices can enhance diagnostic capabilities through repeated measurements and the convenience of at-home testing and (2) home devices, which provide both frequency-volume and uroflowmetry information, have the potential to transform the management of lower urinary tract symptoms.

Experimental Study on the Anti-Scouring Characteristics of Bedrock in Engineering Reservoir Areas That Are Conducive to Sustainable Development

High-speed water flow conditions can cause erosion of the bedrock in engineering areas. Due to the lack of accurate evaluation of bedrock scour and erosion rates, there has been a consumption of manpower and resources without achieving satisfactory engineering outcomes. Therefore, studying the scouring and erosion effects of water flow on bedrock is of significant importance for maintaining the sustainable development and safety of engineering projects. Using the bedrock prototype from the Xiaonanhai site in the upper reaches of the Yangtze River, a model test device was developed to conduct anti-scour tests on the bedrock. The study quantitatively examined the basic physical properties, incipient erosion velocity, and erosion rates of different types of bedrock. The study found that the prototype bedrock under natural exposure, submerged immersion, and alternating wet and dry conditions showed a trend of decreased tensile strength, with the alternating wet and dry conditions being the most detrimental to maintaining the physical properties of the rock mass. The anti-scour velocity of silty claystone and clayey siltstone samples increased with the increase in tensile strength, and the erosion rate increased with the increase in shear stress. If the shear stress is kept constant, the erosion rate decreases with the increase in tensile strength. The erosion rate is inversely proportional to the ratio of the bedrock’s tensile strength to the riverbed shear stress, with the fitting relationship showing a piecewise linear distribution. The research results can provide guidance for the safe production of engineering involving bedrock erosion in engineering reservoir areas that are conducive to sustainable development.

A method of coating life prediction based on high temperature thermal shock life test and three-dimensional heat transfer analysis

In this study, a method for predicting the thermal shock life of coatings is proposed, and a model for predicting the thermal shock life of coatings based on high temperature thermal shock life test and three-dimensional heat transfer analysis is established. Firstly, the thermal shock life of coatings at different cooling and heating cycle temperatures is obtained through a designed thermal shock life testing device for silicide coatings at a wide-temperature range from 500℃ to 3000℃. Secondly, the actual thickness of the coating and the continuous oxidation in the thermal shock life test are taken into consideration. Based on the finite element analysis method, the three-dimensional heat transfer analysis for coatings with different oxidation thickness is carried out to obtain the average value of the maximum thermal stress range on the surface of the coating. Last, the least square method is used to process the data of the life prediction model. Then the parameters of the life prediction model are obtained based on the thermal shock life test of the coating and the average value of the maximum thermal stress range on the coating surface. It turns out that the predicted results of the thermal shock life prediction model established in this study are in good agreement with the tested results. Besides, the relative error is less than 6%. Therefore, the life prediction method proposed in this study can be used to predict the thermal shock life of silicide coatings. What’s more, the research work in this study can also provide a theoretical basis for the life prediction of coating materials.

Field-Programmable Gate Array (FPGA)-Based Lock-In Amplifier System with Signal Enhancement: A Comprehensive Review on the Design for Advanced Measurement Applications.

Lock-in amplifiers (LIAs) are critical tools in precision measurement, particularly for applications involving weak signals obscured by noise. Advances in signal processing algorithms and hardware synthesis have enabled accurate signal extraction, even in extremely noisy environments, making LIAs indispensable in sensor applications for healthcare, industry, and other services. For instance, the electrical impedance measurement of the human body, organs, tissues, and cells, known as bioelectrical impedance, is commonly used in biomedical and healthcare applications because it is non-invasive and relatively inexpensive. Also, due to its portability and miniaturization capabilities, it has great potential for the development of new point-of-care and portable testing devices. In this document, we highlight existing techniques for high-frequency resolution and precise phase detection in LIA reference signals from field-programmable gate array (FPGA) designs. A comprehensive review is presented under the key requirements and techniques for single- and dual-phase digital LIA architectures, where relevant insights are provided to address the LIAs' digital precision in measurement system configurations. Furthermore, the document highlights a novel method to enhance the spurious-free dynamic range (SFDR), thereby advancing the precision and effectiveness of LIAs in complex measurement environments. Finally, we summarize the diverse applications of impedance measurement, highlighting the wide range of fields that can benefit from the design of high performance in modern measurement technologies.

Preparation of CuO–CeO2/CaO Composite Oxides and its Ablation Performances of CO/CO2

ABSTRACT CuO – CeO2/CaO composite oxide was prepared for mine special environment in this study through the solid-phase impregnation method using the traditional CuO – CeO2 and CaO as the CO catalyst and the modified additive, respectively, to address the CO poisoning in underground coal mines effectively. Influences of CaO mass on the ablation performances of CuO – CeO2/CaO were investigated under dynamic and static CO/CO2 heat capture experiments using the self-made activity testing device. Results demonstrated that adding CaO can realize in-situ adsorption of CO2, thus increasing utilization of oxygen and promoting CO catalysis of the prepared composite oxide. The performances of CuO – CeO2/0.15CaO was the best when the dosage of CaO was 15 wt%. The CO reaction capacity and CO2 adsorption capacity reached 1.17 and 0.56 mg·g−1, respectively. The thermodynamic properties and microstructural characteristics of the synthesized composite oxide were systematically investigated utilizing a simultaneous thermal analyzer, Fourier infrared spectrometer, XRD diffractometer, and scanning electron microscope. Adding CaO can also improve the thermostability of the composite oxide and increase active sites on the sample surface. The emergence of adsorption products Ca(OH)2 and CaCO3 proves that CuO – CeO2/CaO has relatively good moisture and CO2 adsorption. Analysis of the ablation performances of CO/CO2 after coal combustion with CuO – CeO2/CaO revealed that the prepared composite oxide not only effectively lowers CO concentration after coal combustion but also adsorbs CO2 during catalysis and decreases smoke risks. The released CO concentration from coal combustion after 240 s can be decreased to less than 0.0024% when the mass ratio of CuO – CeO2/0.15CaO and coal is 1:3. The ablation results confirm that, as a new type of composite material, the CuO – CeO2/0.15CaO composite oxide can provide a new technical means for CO control in coal mines.

Monitoring of Strength Development in Portland Cement Concrete With High Fly-Ash Content at the FAA’s National Airport Pavement Test Facility

Construction Cycle 2 (CC2) at the FAA’s National Airport Pavement Test Facility (NAPTF) included construction of three concrete test items MRC, MRG, and MRS on three different support conditions (crushed-stone subbase, slab on grade, and econocrete stabilized subbase). All three test items were constructed on a CBR 7-8 subgrade. The existing econocrete subbase (P-306) from CC1 test item MRS was used for CC2 MRS. Concrete was placed in the test items using a concrete pump into fully formed 15 ft. (4.57 m) by 15 ft. (4.57 m) slabs. Test results are presented and discussed in this paper. Test results include concrete placement details (slump, air content, concrete temperature), compressive strengths, flexural strengths, elastic modulus from free-free resonance tests on concrete beams and cylinders, portable seismic pavement analyzer (PSPA) tests, and strength results from sawed beams and cored cylinders taken from untrafficked test slabs. Concrete specimens included both laboratory cured and field cured specimens. PSPA tests were performed on the test item slabs at the age of one day and on regular intervals after that, coinciding with the laboratory testing of beams and cylinders. The test results showed good correlation between elastic modulus (from free-free resonance and PSPA tests) and strength values (compressive and flexural strengths) and demonstrated the application potential of a testing device such as PSPA for assessing the early-age strength of concrete.

Study on the Electromigration Organization and Mechanical Properties of Sn2.5Ag0.7Cu0.1RE/Cu Solder Joints

In this study, we designed and manufactured an ideal electromigration testing device for soldering joints to solve the reliability problems caused by temperature and current density changes in the electromigration processes of micro solder joints. We analyzed the effects of temperature and current density on the electromigration β-Sn (single-crystal β-Sn grain) of Sn2.5Ag0.7Cu0.1RE/Cu solder joints, the relationship between the grain orientation and interfacial IMC (intermetallic compound) growth of Sn2.5Ag0.7Cu0.1RE/Cu solder joints, and the mechanical properties of solder joints. The results showed that the angle θ between the c-axis of the β-Sn grain and the current direction for the Sn2.5Ag0.7Cu0.1RE/Cu solder joint gradually decreased to 8.2° when the temperature increased to 150 °C, which accelerated the diffusion of Cu atoms and Cu substrate dissolution. The recrystallization and grain growth of Cu6Sn5 (An intermetallic compound formed by the fusion of copper and tin in a ratio of six to five) grains in the anode region promoted electromigration polarity. Compared with the initial state, the shear strength decreased to 11 MPa, a decrease of 61.3%, the fracture position shifted from the top of the IMC at the cathode interface to the root of the IMC at the cathode interface, and the fracture mode changed from ductile fracture to brittle fracture. With an increase in the current density to 1.1 × 104 A/cm2, θ decreased to 3.2°. In addition, we observed the recrystallization of Cu6Sn5 grains in the anode region and an increase in the grain length and diameter to 6.8–31.9 μm, which further promoted electromigration polarity. Compared with the initial state, the shear strength decreased by 72.5% to 7.8 MPa, and the fracture position shifted from the top of the IMC at the cathode interface to the root of the IMC at the cathode interface. Additionally, the fracture mode changed from ductile to brittle fracture.

Design and Validation of a Testing Device for Sediment-Induced Erosion Based on Similarity Theory

Sediment-induced erosion is a primary cause of failure in the flow-passage components of Francis turbine units. This study adopted the Realizable k–ε turbulence model to numerically simulate the effects of sediment-induced erosion on the guide components of Francis turbines. Specifically, using flow similarity theory, a testing device suitable for studying the sediment-induced erosion behavior of turbine vanes was designed, and the similarity between the flow fields of actual vanes and testing device vanes was validated. The results revealed a high degree of consistency between the near-wall flow velocities and sediment volume fractions experienced by both vanes at 0.5 vane height. For instance, the midsection of the suction side of the stay and guide vanes exhibited relatively stable velocities of 12.5 m/s and 42 m/s, respectively. Further, sediment volume fractions at the leading edge of the stay and guide vanes reached 0.015, respectively, owing to the impact of sediment-laden flow. Overall, the proposed testing device design methodology can predict the operational lifespan of actual vanes and assess the wear resistance of various coating materials. These findings provide valuable scientific guidance for optimizing the design and operation of hydropower plants.

Multiplanar Semicircular New-Generation Implant System Developed for Proximal Femur Periprosthetic Fractures: A Biomechanical Study.

Background and Objectives: The study aimed to evaluate a newly designed semicircular implant for the fixation of Vancouver Type B1 periprosthetic femoral fractures (PFFs) in total hip arthroplasty (THA) patients. To determine its strength and clinical applicability, the new implant was compared biomechanically with conventional fixation methods, such as lateral locking plate fixation and a plate combined with cerclage wires. Materials and Methods: Fifteen synthetic femur models were used in this biomechanical study. A Vancouver Type B1 periprosthetic fracture was simulated by osteotomy 5 mm distal to the femoral stem. The models were divided into three groups: Group I (lateral locking plate fixation), Group II (lateral locking plate with cerclage wires), and Group III (new semicircular implant system). All fixation methods were subjected to axial loading, lateral bending, and torsional force testing using an MTS biomechanical testing device. Failure load and displacement were measured to assess stability. Results: The semicircular implant (Group III) demonstrated a significantly higher failure load (778.8 ± 74.089 N) compared to the lateral plate (Group I: 467 ± 68.165 N) and plate with cerclage wires (Group II: 652.4 ± 65.474 N; p < 0.001). The new implant also exhibited superior stability under axial, lateral bending, and torsional forces. The failure load for Group III was more robust, with fractures occurring at the screw level rather than plate or screw detachment. Conclusions: Compared to traditional fixation methods, the newly designed semicircular implant demonstrated superior biomechanical performance in stabilizing Vancouver Type B1 periprosthetic femoral fractures. It withstood higher physiological loads, offered better structural stability, and could be an alternative to existing fixation systems in clinical practice. Further studies, including cadaveric and in vivo trials, are recommended to confirm these results and assess the long-term clinical outcomes.

Validation of Point-of-Care Testing Device for Serum Ferritin Estimation in an Outpatient Facility in India

Validation of Point-of-Care Testing Device for Serum Ferritin Estimation in an Outpatient Facility in India

Dynamics simulation analysis of the melting process of ice on the surface of aramid IIIA fabrics

In many industries, workers are facing the inconvenience caused by icing on fabrics. Fabric is a porous material, and researchers generally hold that porous material is not suitable for being used as an anti-icing material. Therefore, research on the anti-icing properties of fabrics have not attracted researchers' attention, thus relevant research results are few. The influence of sample surface wettability on snow melting has been rarely studied in depth. In this paper, a test device for testing the melting rate of ice on the surface of a sample was developed. Based on this experiment, a simulation model for simulating the melting process of the ice on the aramid IIIA fabric samples was established based on the melting promoting anti-icing theory. This work also indicates that the use of computational models in the study of ice melting processes is successful. Results show that the relative error between the simulated value and the experimental value was 1.63%. These computational models provide details on the phase transition and temperature changes of ice during the melting process, which are difficult to observe in experiments. Meanwhile, the simulated phase transition of ice is consistent with actual observations. The results indicate that the simulation model established in this article can be extended to study the melting process of ice on aramid IIIA fabric samples, and can be used to guide the study of the anti-icing performance of aramid IIIA fabrics.

Validation of a Portable Ionized Calcium Detection Device and Changes in the Ionized-to-Total-Calcium Ratio in the Blood of Postpartum Holstein Cows.

The calcium requirements of dairy cows increase dramatically soon after calving, and many cows have subclinical hypocalcemia, adversely affecting health and performance. Traditional laboratory tests for calcium are complex and not easily adapted to rapid point-of-care applications. The objectives were to evaluate a portable iCa testing device, Horiba LAQUAtwin Ca-11C, for measuring ionized calcium (iCa) in the whole blood of dairy cows and to investigate the iCa-to-total-calcium (tCa) ratio in blood collected from dairy cows within 9 days after calving. This study was conducted on two large dairies in northern China. First, blood samples were collected from 246 cows within 3 days after calving, and whole-blood iCa concentrations were measured with a Horiba LAQUAtwin Ca-11C and Abbott i-STAT 1. In addition, 885 blood samples were collected from 102 dairy cows between calving and 9 days postpartum, with iCa concentrations measured using a Horiba LAQUAtwin Ca-11C and tCa concentrations determined by a fully automated biochemical analyzer. The Horiba LAQUAtwin Ca-11C and Abbott i-STAT 1 had significant consistency in the measurement of ionized calcium concentration in whole blood (the frequency of differences between the measured values was within ±20% of the average, reaching 95.53%), and the measurement results of the two instruments were correlated (Deming regression analysis R2 = 0.87). This implied the potential application of the Horiba LAQUAtwin Ca-11C as a simplified device for measuring iCa in dairy farms for on-site testing. Within the first 9 days after calving, the ratio of ionized calcium to total calcium fluctuated but overall remained within the range of 44.2 to 47.22%. Furthermore, significant variations in the ratio among individual cows indicated that individual differences and physiological states of cows affected calcium metabolism. This study identified the potential to use the Horiba LAQUAtwin Ca-11C for point-of-care testing on dairy farms. Nevertheless, the impacts of factors such as health status and individual cow differences on the ratio of ionized calcium to total calcium still require further investigation.

Plantar cutaneous sensation is independently associated with postural balance and lower limb motor function in older adults: the Shizuoka study.

A relationship between decreased plantar cutaneous sensation and impaired balance function has been reported in patients with peripheral neuropathy and diabetes. This cross-sectional study aimed to investigate the relationship between plantar sensation and postural balance, as well as the association between plantar sensation and sarcopenia-related motor function in community-dwelling older adults. The participants included 1659 community-dwelling older adults with a mean age of 74 ± 5years, of which 43% were male patients. Plantar cutaneous sensation thresholds were assessed using an automatic plantar sensation testing device. Postural balance was measured using one-leg standing (OLS) time. Grip strength, five-time sit-to-stand (STS) time, and normal gait speed were measured as components of muscle strength and physical function related to sarcopenia. The skeletal muscle mass index (SMI) and leg phase angle were obtained using bioelectrical impedance analysis. Age, sex, body mass index, and leg phase angle, but not SMI and grip strength, were independently associated with the plantar sensation threshold. Plantar sensation threshold was independently associated with the OLS time (P = 0.001) and STS time (P = 0.001) after adjusting for potential confounders. No significant association was found between plantar sensation threshold and normal gait speed (P = 0.741). Plantar sensation was independently associated with postural balance and lower limb function in community-dwelling older adults. The assessment of plantar sensation could be useful for identifying factors contributing to poor postural balance and lower limb motor function.