Test Device Research Articles

Optimisation of artefact detection in photoplethysmography heart rate data: influence of different classifiers in machine learning models

Abstract Background Heart rate (HR) tracking by wrist-worn devices using photoplethysmography (PPG) could assist in continuously following up physical activity. However, the accuracy can be impacted by (motion) artefacts. Machine learning models could help to recognise artefacts in PPG-based HR data. The choice of classifier in these machine learning models is a determing factor for task performance of the model. Purpose This study evaluates and determines the optimal classifier for a new machine learning-based approach to enhance the reliability of artefact detection in PPG-based HR data. Methods A total of 62 participants (27 cardiac rehabilitation patients, 35 healthy athletes) wore both a test device and a reference device measuring HR continuously for 24 hours. A training dataset was prepared, assigning two independent labels (i.e. anomaly and activity) to each HR episode based on the reference device data. Fitbit data were processed using our in-house designed artefact removal procedure, which involves the application of two classification models: one for anomaly detection and another for activity detection. Four distinct classifiers were employed for both models: Balanced Bagging, Balanced Bagging with Random Forest, Balanced Random Forest, and Logistic Regression. Each classifier was evaluated using area under the receiver operating characteristic curve (ROC-AUC), accuracy, sensitivity and specificity. Results Of the 1,647,328 HR data points collected, 103,095 (6.26%) were identified as artefacts. Figure 1 and Figure 2 summarise the performance of the distinct classifiers for the anomaly model and the activity model, respectively. Balanced Bagging and Balanced Bagging with Random Forest consistently demonstrate the highest AUC values and accuracies across both anomaly and activity detection models (anomaly detection: AUC = 0.95, accuracy = 89-85%; activity detection: AUC = 0.98, accuracy = 95%). Comparing these two, Balanced Bagging with Random Forest emerges as the preferred option, given the highest sensitivity in both anomaly detection (93%>86%) and activity detection models (99%>96%). In contrast, Balanced Random Forest and Logistic Regression exhibit inferior performance. In the anomaly detection model, Balanced Random Forest exhibits a lower sensitivity of 75%, while Logistic Regression performs even worse with a sensitivity of 25%. Similarly, in the activity detection model, both Balanced Random Forest and Logistic Regression demonstrate diminished performance. Conclusions Balanced Bagging with Random Forest emerges as the optimal classifier to detect anomalies and activities in continuous PPG-based HR data, thus contributing to the optimisation of our in-house designed procedure for removing artefacts. This processing aims to provide a reliable and automatic way for continuous HR monitoring, which can help monitor and guide physical activities.

Potassium Fertilizer Application Rates for Fertigated Edamame Grown on Low-K Soils

Edamame, a legume consumed fresh as a vegetable, is highly nutritious, particularly protein-rich, and holds significant economic value. However, its cultivation faces challenges, especially on dry land, due to water scarcity and limited nutrient availability, particularly potassium (K). This study, which investigated the impact of potassium fertilization rate on edamame cultivation, underscores the need for further research. The study utilized a single factor, potassium fertilization rate, arranged in a completely randomized block design. Potassium rates consist of 0% X, 50% X, 100% X, 150% X, and 200% X, where X represents the recommended potassium fertilization rate according to the dry soil test device (DSTD) guidelines. Each treatment was replicated five times. Data were analyzed using ANOVA at a 5% significance level, and any significant effects were further examined using orthogonal polynomial and regression analysis. The results indicated that potassium fertilizer rates did not significantly affect edamame height, pod weight per plot, and marketable yield. However, the study identified the optimal potassium fertilizer rate, which was between 83%X and 119%X, equivalent to 83–119 kg.ha⁻¹ of KCl (50–72 kg.ha⁻¹ of K₂O). This range positively increased total branch yield, productive branches, number of flowers, pod weight per plant, number of pods per plant, and plant dry weight, producing a quadratic response pattern. The study recommends further research to optimize potassium fertilizer doses based on DSTD recommendations, particularly at a low K nutrient status, to maximize marketable yields through fertigation.

Study on the strength influence mechanism and cracking mechanism of stone powder-cement floor grouting materials

Underground grouting is a concealed project, and it is difficult to test the strength of grouting stones in engineering practice. Aiming at the problems of high confined water pressure and strong water-richness of the roadway floor, a pressure filtration test device was developed, and a PFC2D uniaxial compression model was established to study the variation law of stone strength and crack evolution mechanism of grouting materials under different grouting pressures. The results show that with the increase of pressure filtration value, the amount of slurry dehydration increases, the pore water pressure dissipates, the pores between particles are tightly compressed, the contact force between particle skeletons increases, and the strength of stone body increases. Under the condition of the same cement powder ratio (mass ratio of cement to stone powder) or stone powder particle size, the strength of stone body of stone powder-cement grouting material increases with the increase of pressure filtration value. The stress-strain curves of the stone body with different pressure filtration values all experienced three stages: continuous elasticity, fracture expansion and strength failure. Before the peak, the number of cracks increases slowly; after reaching the peak, the micro-cracks extend rapidly and the number increases rapidly, resulting in the final tensile failure of the specimen. This study can provide a basis for the selection of grouting engineering material ratio and grouting pressure parameters.

A novel model for low-permeability reservoir numerical simulation considering dynamic capillary force

ABSTRACT Capillary force is not only affected by water saturation but also affected by fluid flow velocity, which is necessary to modify the prior numerical simulation methods. First, a dynamic capillary force testing device was developed, then, an experimental procedure was adopted to measure the dynamic capillary force curve. Three dynamic capillary force curves were obtained under different displacement velocity conditions. Finally, the dynamic capillary force was introduced into the flow equation of low-permeability reservoir numerical simulation. The oil-phase equation and water-phase equation were discretized in three-dimensional space, and the IMPES method was used to solve the water saturation and pressure difference. The calculation results between the traditional numerical simulation method and the novel method under heterogeneous and inhomogeneous conditions were analyzed. The results reveal that the difference in water cut is mainly reflected in the rapid rise of water cut. In the early stage of rapid increase, the water cut calculated by the new method is slightly higher than traditional method. When the water cut is more than 65%, the water cut calculated by the new method is slightly lower than the traditional method.

The effect of different treatment protocols on shear bond strength in resin composite restoration repair

BackgroundIt was aimed to investigate the effect of sandblasting and laser surface treatment on shear bond strength in composite restoration repair in vitro.MethodsA micro-hybrid composite (Filtek Z250, 3 M-ESPE, USA) was used to prepare 120 samples. The samples were subjected to a thermal cycle test 5,000 times between 5 and 55 0C, and they were randomly divided into 12 groups (n = 10). No surface treatment was performed in Groups 1 to 4, which were designed as control groups. The surfaces of the samples in Groups 5 to 8 were sandblasted with a Cojet device, and the surfaces of the samples in Groups 9 to 12 were applied Er, Cr: YSGG laser. After the sample surfaces were divided into groups with and without acid etching, universal adhesive was applied, and the repair process was performed using Filtek Z250 or nano-filled resin composite (Filtek Ultimate, 3 M-ESPE, USA). The thermal cycle test was repeated 5,000 times between 5 and 55 0C on all repaired samples. The repair shear bond strength of the samples was measured using a universal testing device (Shimadzu IG-IS, Kyoto, Japan). The fracture types were evaluated by optical microscopy and scanning electron microscopy (SEM). Statistical analyses of the findings were evaluated by the Kruskal Wallis test and Mann Whitney U test at 0.05 significance degree.ResultsThe highest mean shear bond strength values were obtained from the samples sandblasted with CoJet, followed by Er, Cr: YSGG laser, and the control group. It was determined that there was a significant difference between the mean shear bond strength values obtained from the control group and the other surface treatment groups (p < 0.05). In general, significantly higher mean shear bond strength values were obtained when the universal adhesive was applied in total-etch mode compared to the application in self-etch mode (p < 0.05). Additionally, it was determined that higher shear bond strength values were obtained with Filtek Ultimate compared to Filtek Z250 (p < 0.05).ConclusionWithin the limitations of this study, it can be concluded that the use of universal adhesive in total-etch mode, in addition to surface treatments on the resin composite surface in the repair protocol and the use of nano-filled resin composite as repair material can increase the mean shear bond values in repair.

The evaluation of a novel single-lead biopotential device for home sleep testing.

This paper reports on the clinical evaluation of the sleep staging performance of a novel single-lead biopotential device. 133 patients suspected of obstructive sleep apnea were included in a multi-site cohort. All patients underwent polysomnography and received the study device, a single-lead biopotential measurement device attached to the forehead. Clinical endpoint parameters were selected to evaluate the device's ability to determine sleep stages. Finally, the device's performance was compared to the clinical study results of comparable devices. Concurrent PSG and study device data were successfully acquired for 106 of the 133 included patients. The results of this study demonstrated significant similarity in overall sleep staging performance (5-stage Cohen's Kappa of 0.70) to the best-performing reduced-lead biopotential device to which it was compared (5-stage Cohen's Kappa of 0.73). Contrary to the comparator devices, the study device reported a higher Cohen's Kappa for REM (0.78) compared to N3 (0.61), which can be explained by its particular measuring electrode placement (diagonally across the lateral cross-section of the eye). This placement was optimized to ensure the polarity of rapid eye movements could be adequately captured, enhancing the capacity to discriminate between N3 and REM sleep when using only a single-lead setup. The results of this study demonstrate the feasibility of incorporating a single-lead biopotential extension in a reduced-channel home sleep apnea testing setup. Such incorporation could narrow the gap in the functionality of reduced-channel home sleep testing and in-lab polysomnography without compromising the patient's ease of use and comfort.

Assessment of diagnostic accuracy of Gazelle: A point-of-care testing device for screening β-thalassemia trait

Background &amp; objectives Timely detection of population with β-thalassemia trait (BTT) followed by genetic counselling is an advocated method of preventing the birth of a child with β-thalassemia major. In this study we aim to assess the diagnostic accuracy of Gazelle, a point-of-care (POC) testing device, in screening for BTT in hospital laboratory setting. Methods Standards for Reporting Diagnostic Accuracy (STARD) guidelines were followed in developing study design, recruiting study participants and sample size calculation for the current research. A consecutive sample of 446 participants was recruited for this study and was tested for the reference test Gazelle as well as the gold standard cation exchange high performance liquid chromatography (CE-HPLC). Low serum ferritin levels are known to interfere with the production of HbA2 and in turn lead to false negative results. Hence, the study population was divided into two categories with respect to a cut off value of 15ng/dl of serum ferritin and the results were analyzed. Results Overall diagnostic accuracy of Gazelle for detecting BTT was found to be 95.3 per cent with a confidence interval (CI) of (92.9 - 97.1) and the sensitivity was 94.5 per cent with a 95% CI of (84.8 - 98.8). When analyzed by the serum ferritin level the diagnostic accuracy was found to be 94.7 per cent (91.1% - 97.1%) and 95.7 per cent (91.8% - 98.1%) for participants with serum ferritin level as &gt; 15 ng/ml and &lt; 15 ng/ml, respectively. Interpretation &amp; conclusions This study found Gazelle to be a good screening tool for β-thalassemia trait with high sensitivity, specificity and accuracy. However, it is recommended that the final confirmation of the diagnosis done by a diagnostic test like HPLC or Capillary Zone Electrophoresis (CZE).

Model test study on the dynamic failure process of tunnel surrounding rocks in jointed rock mass under explosive load

The presence of joints can significantly reduce the integrity and stability of an engineering rock mass. Under dynamic loads, such as from blasting excavation, the key blocks divided by joints may be destabilized and prone to sliding, potentially leading to engineering geological disasters like rockbursts. To study the dynamic instability process, similar materials for the rock mass and joints were developed based on the similarity theory, and a tunnel model in the jointed rock mass was constructed. Subsequently, a detonating fuse was used to generate a dynamic load, and the dynamic instability process of the tunnel surrounding rock in the jointed rock mass under explosive load was studied using the geotechnical multifunctional testing device. The deformation characteristics and dynamic instability process of the tunnel surrounding rock were analyzed using acceleration sensors, resistance strain gages, linear variable displacement transducers and motion camera. The study shows that the acceleration at the tunnel vault is significantly greater than at the straight wall and floor under blast loads, with differences reaching an order of magnitude. Acceleration waveforms were classified into three categories based on peak characteristics, explained through the propagation of explosive stress waves. Additionally, strain and displacement at the tunnel arch were also significantly greater than in other areas, indicating more severe stress concentration and dynamic damage at the arch, necessitating reinforced support in tunnel excavation. The entire dynamic instability process of the tunnel surrounding rock was successfully recorded using a motion camera. The dynamic failure process was divided into several phases, the appearance of cracks on the joint surface, particle ejection accompanied by the dropping of jointed blocks, a significant drop of the jointed blocks, and return to calm. The dynamic failure modes include the dropping and rotation of jointed blocks, local particle ejection, and shear cracks on jointed block.

Effects of radiotherapy dose and application time on the load-to-failure values of teeth filled with different sealers

BackgroundThe materials used in root canal filling and radiotherapy (RT) application can affect the load-to-failure of the teeth. This study aimed to compare the load-to-failure of the teeth filled with AH Plus (AHP) or AH Plus bioceramic (AHPB) before or after 60 Gy- and 70 Gy-dose radiotherapy.Materials and methodsOne hundred and ten maxillary incisors were endodontically prepared up to ProTaper Next X4 instruments. The teeth were randomly divided into 5 main groups as: non-irradiated, root canal treatment (RCT) before 60 Gy radiotherapy, RCT before 70 Gy radiotherapy, RCT after 60 Gy radiotherapy, RCT after 70 Gy radiotherapy. These groups were divided into 2 subgroups for filling material: AHP ve AHPB. After filling and radiotherapy procedures, the teeth were fixed on the thermoplastic mask plane. The plane were placed in the middle of a rectangular prism shaped glass phantom, and irradiated via a linear accelerator device. The teeth were then embedded in cylindrical acrylic blocks and the force (N) that caused the fracture was recorded under the Universal testing device. Student t-test was used for statistical comparisons. Statistical significance level was determined as p < 0.05.ResultsAfter 70 Gy dose radiotherapy, the group filled with AHPB showed statistically significantly lower fracture strength than the group filled with AHP (p < 0.05). In the control group, before 60 Gy RT group, after 60 Gy RT group, and before 70 Gy RT group, the sealers had statistically significantly similar load-to-failure. (p > 0.05).ConclusionThe group filled with AHPB caused a lower fracture strength than the group filled with AHP following a 70 Gy dose of RT. The sealers in the control group, before 60 Gy RT group, after 60 Gy RT group, and before 70 Gy RT group exhibited comparable load-to-failure values.

OUT–OF–STEP protection in rotating generation networks for hydrogen fuel production. Modeling conditions to test its algorithms

The testing of relay protection devices is an extremely important task on which the stable and safe operation of the power systems depends. One of the most complex and responsible kinds of protection in networks with rotating generation, which includes hydrogen fuel generation, is protection against loss-of-synchronism. Integration of heterogeneous generating electrical devices based on renewable energy sources and based on a hydrogen fuel cell is associated with the need for reliable relay protection. It disconnects tie-lines between the systems in out-of-step conditions. And it is a challenging task to simulate input signals corresponding to the exact settings of the out-of-step protection to make sure it operates correctly. This is because one has to simulate exact parameters of impedance locus (its radius, coordinates of the center in the impedance plane, spin direction, speed, etc.) while available tools embedded in testing devices often don’t support such parameters directly. To deal with the problem, the authors present the approach to simulate instantaneous values of line currents and phase-to-ground voltages during the out-of-step operation. These electrical signals form the locus of the impedance vector with the desired parameters to test the operation of the out-of-step protection devices. The software based on the proposed algorithm also provides a graphical representation of the simulation results. All the proposed solutions proved to reduce the time required for commissioning of out-of-step protection and thereby increase tests quality and speed.

Comparison of low-density lipoprotein cholesterol (LDL-c) estimates by in-lab and point-of-care devices in the context of emerging LDL-c equations

Abstract Low-density lipoprotein cholesterol (LDL-c) and lipid measurements are used for hyperlipidemia diagnosis, cardiovascular disease risk classification, and medication management. Millions of lipid panels are performed annually. Given the widespread need for lipid testing, there are two CLIA-waived point-of-care (POC) lipid testing devices. These devices were FDA-approved using the Friedewald equation to estimate LDL-c based on measurements of (triglycerides (TG), high-density lipoprotein cholesterol (HDL-c), and total cholesterol (TC). By contrast, for laboratory-based LDL-c estimation, the Friedewald equation is being replaced by newer, more accurate equations such as the NIH-Sampson equation. These equations use the same lipid panel results to estimate LDL-c and only differ in the arithmetic of the estimation. This study evaluates how differences between the in-clinic POC machines and in-laboratory lipid measurements affect the estimated LDL-c results and are compounded by differences in the equations used for LDL-c estimation. This retrospective observational study collected deidentified lipid results (TG, HDL-c, TC, LDL-c) and demographic data (age, gender) for all samples that had lipid panel results from in-lab and POC within twenty-four hours of each other in a single hospital system between 2014 and 2023. Three hundred twenty samples were identified; samples with non-numerical values or results outside of the reportable range for TG, HDL-c, or TC were not included in subsequent LDL-c calculations using the Friedewald and NIH-Sampson equations (69 results). Patients under the age of 18 were excluded (2 results). Two hundred and forty-nine samples met inclusion criteria; this cohort showed non-significant differences in lipid, age, and gender distributions relative to all POC results tested in the same time frame. Consistent with prior reports, we observed discordance between POC and the in-lab lipid measurements, particularly for TG (Bland-Altman: bias:-23.04 mg/dL, standard deviation:61.3 mg/dL). These analytical differences may not change clinical management if the cardiovascular risk classification using estimated LDL-c is unchanged. However, the risk classification based on the in-lab versus in-clinic testing differed for 20% of patients. The most pronounced difference in LDL-c estimation occurred when the POC machine used Friedewald and in-lab testing used NIH-Sampson, and resulted in 5% more patients differentially classified. Regardless of testing platform, more patients are categorized as higher risk on an individual and population-based level with the NIH-Sampson equation. This study highlights the need for transparency in lipid panel reports regarding which LDL-c equation is used in both POC and in-lab testing formats, and the need for readily available tools for conversion between different LDL-c estimation equations.

Progress Analysis of Bonding Performance of GFRP Reinforcement to Concrete

The article briefly summarizes the latest progress of research on the bonding properties of GFRP bars to concrete at home and abroad. It analyzes three test methods for studying the bond properties of GFRP bars, namely: losberg test, standard specimen test, and beam test, and briefly introduces the pullout test device for the pullout test. The bonding mechanism and the influence of the surface form of GFRP bars, concrete strength, diameter size, anchorage length, protective layer thickness and other influencing factors on the bond strength are analyzed and summarized, among which the diameter size and anchorage length have a greater influence on the bond strength. Suggestions are also made to address the shortcomings of the existing research, which provide a basis for a more in-depth study of the bond strength of GFRP bars in the future.

Exploring the impact of sepak takraw ball heading on brain injury risk: An analytical and experimental investigation

Sepak takraw, a unique sport resembling volleyball but played with the legs, is popular in Asia. Players often use their foreheads to receive the ball, exposing them to potential brain injuries. This research evaluates the potential for brain injuries from heading in sepak takraw. Using both analytical and experimental approaches, we developed a mathematical model adapted from soccer-related studies to predict peak linear acceleration (PLA). We also conducted laboratory experiments to measure PLA and peak rotational acceleration (PRA) using a ball launcher and an Anthropomorphic Test Device (ATD). The mathematical model demonstrated a high level of accuracy in PLA prediction, confirming its reliability. Comparative analysis with soccer and water polo studies revealed that the measured PLA, PRA, and Head Injury Criteria (HIC) values for sepak takraw are below suggested concussion thresholds, indicating a lower risk of brain injury. However, this assessment does not account for the cumulative effects of repetitive head impacts, which increase the risk of brain injury over time. Despite sepak takraw’s distinct play style, the findings indicate that while the inherent risk of head injury from single impacts may be low, the potential long-term effects of repetitive impacts warrant further investigation. This study enhances the understanding of sports-related brain injuries and highlights the need for further research into subconcussive impacts and the development of protective measures. Our research paves the way for more comprehensive investigations, including field experiments, which are crucial for a nuanced understanding of sepak takraw’s impact dynamics.

Multi-channel portable odor delivery device for self-administered and rapid smell testing

To improve our understanding of the perception of odors, researchers are often required to undertake experimental procedures with users exposed to multiple odors in a variety of settings, including to diagnose smell loss in clinics and care homes. Existing smell tests are typically administered using multiple sniffing pens, manually presented to patients by a highly specialized nurse using a time-consuming and complex testing paradigm. Automated odor delivery devices, such as olfactometer systems, exist but are expensive, bulky and typically lab based, making them difficult to use for on the ground odor delivery. Here we have developed a portable, affordable, odor delivery device that can deliver 24 odors through individual channels with high temporal precision and without cross-contamination. The device allows for the rapid, flexible sequencing of odors via digital control using a mobile application and has been experimentally validated in the lab, as well as tested on patients. The design provides several advantages for investigating olfactory perception and offers the possibility that users can one day self-administer smell tests in a range of settings, including at home, allowing smell healthcare services to evolve and become part of a routine practice and self-care culture.

Nondestructively Determining Soluble Solids Content of Blueberries Using Reflection Hyperspectral Imaging Technique

Effectively detecting the quality of blueberries is crucial for ensuring that high-quality products are supplied to the fresh market. This study developed a nondestructive method for determining the soluble solids content (SSC) of blueberry fruit by using a near-infrared hyperspectral imaging technique. The reflection hyperspectral images in the 900–1700 nm waveband range were collected from 480 fresh blueberry samples. An image analysis pipeline was developed to extract the spectrums of blueberries from the hyperspectral images. A regression model for quantifying SSC values was successfully established based on the full range of wavebands, achieving the highest RP2 of 0.8655 and the lowest RMSEP value of 0.4431 °Brix. Furthermore, three variable selection methods, namely the Successive Projections Algorithm (SPA), interval PLS (iPLS), and Genetic Algorithm (GA), were utilized to identify the feature wavebands for modeling. The models calibrated from feature wavebands generated an RMSEP of 0.4643 °Brix, 0.4791 °Brix, and 0.4764 °Brix, as well as the RP2 of 0.8507, 0.8397, and 0.8420 for SPA, iPLS, and GA, respectively. Furthermore, a pseudo-color distribution diagram of the SSC values within blueberries was successfully generated based on established models. This study demonstrated a novel approach for blueberry quality detection and inspection by jointly using hyperspectral imaging and machine learning methodologies. It can serve as a valuable reference for the development of grading equipment systems and portable testing devices for fruit quality assurance.

7089 The Effects of Asprosin on Reproductive Parameters in the Rats

Abstract Disclosure: H. Kelestimur: None. Z. Oz: None. M. Ozdede: None. &amp;. Serhatlioglu: None. E. Kacar: None. B. Yilmaz: None. Purpose: Asprosin, a novel glucogenic adipokine produced by the fibrillin 1 (FBN1) gene, is integral to the body's energy regulation processes. Generated and released by white adipose tissue during fasting, asprosin affects the hypothalamic-pituitary-gonadal (HPG) axis, impacting reproduction. While its effects on metabolic parameters are well established, the understanding of its impact on reproductive health and functionality is still emerging. This study investigates the effects of exogenous asprosin administration on the reproductive capabilities of male and female rats. Materials and Methods: Forty-eight Sprague-Dawley rats, 21 days old and weighing 35±2 grams, were divided into control and asprosin-treated groups (n = 12 per group, for both genders). This approach allowed direct comparison between treated and untreated groups. From postnatal day 21, treatment groups received daily intraperitoneal injections of asprosin (500 ng/kg) for ten weeks (male) and eight weeks (female), while control groups received only saline (1 ml/kg). The study examined various reproductive parameters, including those related to pubertal maturation and sexual behavior, and conducted hormonal analyses on blood samples collected at the experiment's conclusion. Results: Asprosin administration did not alter puberty onset or weight in either gender. However, asprosin-treated rats showed significantly earlier sperm formation in males and earlier estrus in females compared to controls. In male sexual behavior, asprosin reduced intromission latency and increased ejaculation frequency. While interaction with females remained unchanged, asprosin notably increased time near males and male preference ratio. The rate of male investigation preference and the activity index (frequency of passing through the test device's center) also significantly increased in the asprosin-treated group. Conclusion: These findings suggest that asprosin may stimulate the reproductive system in both male and female rats. They highlight the potential role of asprosin in reproductive biology and underscore the need for further research to fully understand the mechanisms by which asprosin influences reproduction. Such studies could significantly advance our knowledge in endocrine regulation. Acknowledgement: This study was supported by TUBITAK (Project No: 220S744). Presentation: 6/1/2024

Understanding the interaction forces between shield-triggered autoinjectors and skin: an in-depth noninvasive study

ABSTRACT Objective This noninvasive study aimed to understand the interaction between shield-triggered autoinjectors (AI) and skin at the point of activation, hypothesizing that the AI’s housing absorbs a significant amount of the user-applied force depending on shield design and skin characteristics. Methods Twenty-seven volunteers used a test device measuring applied force versus shield force and indentation depth relative to shield length (2,4,6,8 mm) in standing and sitting positions. Results Significant differences were found between applied and shield force for the different shield lengths. Shorter shields resulted in significantly lower force transfer coefficients, with means ranging from 0.72 for the 2 mm shield to 0.94 for the 8 mm shield. ANOVA revealed statistically significant factors (p < .05), including position and gender, with females generally having lower coefficient values. Indentation depth increased with higher forces and varied significantly between positions without significant shield length impact. Conclusion The findings confirm that an increase in shield length at the point of activation reduces skin friction with the housing, resulting in less force loss and a lower device activation force perceived by the user. Force loss can be further reduced by standing up. Understanding device-tissue interactions will support development of better AIs with fewer user failures.

Validation of the TMB-2296-BT blood pressure monitor in adults according to the ISO 81060-2:2018 + Amd.1:2020.

This study aimed to validate the accuracy of the test device (TMB-2296-BT) blood pressure (BP) monitor in adults according to International Standard Organization (ISO) 81060-2:2018 + Amd.1:2020 universal standard protocol, which is a digital monitor. Three trained observers used the same arm sequential method to compare the SBPs and DBPs measured by the test device with those measured by the reference device (mercury sphygmomanometer). For the test device with cuff ranging from 22 to 32 cm, there are 88 adults, with a male-to-female ratio of 35 : 53. The mean difference and SD between reference BPs and test device BPs readings were (0.21 ± 2.59)/(0.66 ± 2.12) mmHg for SBP/DBP for criterion 1, and (0.21 ± 2.07)/(0.66 ± 1.76) mmHg for SBP/DBP for criterion 2. For the test device with cuffs ranging from 22 to 42 cm, there are 87 adults, with a male-to-female ratio of 49 : 38. The mean difference and SD between reference BPs and test device BPs readings were (-1.62 ± 2.80)/(0.12 ± 3.01) mmHg for SBP/DBP for criterion 1, and (-1.62 ± 2.35)/(0.12 ± 2.60) mmHg for SBP/ DBP for criterion 2. And for the test device with cuff arm circumference sizes of 22-32 cm and 22-42 cm fulfilled both validation criterion 1 and 2 of the ISO 81060-2:2018 + Amd.1:2020 standard and can be recommended for both clinical and self/home BP measurement in adults.

Development of textile switch using conductive embroidery on pre-stretched fabric

In this study, a novel production method for textile switches has been developed using conductive embroidery on pre-stretched fabric. A specially designed fixtures that can stretch and fix the fabric were prepared using 3D printing. Embroidery technique was used for selective stiffening to form three-dimensional shape. The relationship between embroidery design parameters and the physical properties of resulting textile switch has been investigated. An automated testing device has been developed to assess the reliability of textile switches. Test results showed that the textile switches developed in this study maintained their functionalities even after 30,000 clicks, providing perceptible haptic feedback to users.

The grouting plugging mechanism of layered jointed rock mass considering the time-varying yield stress of grout

Slurry retention in fractures decreases after grouting is completed and the pressure supply is stopped, which affects the grouting sealing effect and prevents or restrains the occurrence of such adverse conditions. Based on the time-varying yield stress of grout, a theoretical analysis model of grouting diffusion decay is established, the decay height variation function and the minimum pressure stabilisation time calculation formula are derived, and the sealing mechanism of a jointed rock mass with multiple joints is studied. Moreover, a 3D visualisation laboratory test device for grouting diffusion decay of a jointed rock mass with layers was developed to analyse the diffusion and decay process of grout with different water-cement (W/C) ratios visually, and the correctness of the theoretical model was verified. The results show that: (1) the W/C ratio of grout should not be greater than 2, otherwise it is difficult for grout to remain in the cracks; (2) a large fissure opening easily spreads grout but is not conducive to the retention of grout; and (3) the time of stable pressure determines the retention rate of the slurry in the crack. When the horizontal crack opening width is 3 mm and the W/C ratio of the slurry is 1, the minimum stable pressure time to achieve a better sealing effect is 810 s. The research results can be used to reasonably plan the grouting time and improve the grouting efficiency to ensure the grouting effect, which is crucial for improving the theoretical system of grouting technology.