Pressure Test Research Articles

Long-Term Blood Pressure Variability and Visual Field Progression in Glaucoma

ImportanceLong-term variability of blood pressure may be associated with visual field (VF) progression in patients with glaucoma.ObjectivesTo investigate the association between blood pressure parameters and VF progression over time in patients with glaucoma.Design, Setting, and ParticipantsThis retrospective cohort study of longitudinal data included patients with suspected or confirmed glaucoma who were selected from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Patients underwent blood pressure and VF testing from November 2000 to December 2022, and data were analyzed in October 2023.ExposureSuspected or confirmed glaucoma.Main Outcomes and MeasuresMean and SD values of blood pressure variables were calculated for systolic and diastolic arterial pressures. These parameters were incorporated into multivariable mixed-effect models to investigate the association between blood pressure parameters and mean intraocular pressure with rates of VF mean deviation loss. Interaction terms between blood pressure parameters and mean intraocular pressure were also included in the models.ResultsA total of 1674 eyes from 985 patients were assessed (mean [SD] age, 61.2 [0.4] years; 563 female [57.2%]). The mean rate of VF mean deviation change was −0.13 (95% CI, −0.16 to −0.10) dB/y over a mean follow-up of 8.0 (95% CI, 7.7-8.2) years. The interaction terms of higher mean blood pressure and higher SD of blood pressure were associated with faster annual mean deviation changes for both mean arterial pressure (0.02 [95% CI, 0.01-0.04] dB/y per 1-mm Hg higher; P = .001) and diastolic arterial pressure (0.02 [95% CI, 0.01-0.03] dB/y per 1-mm Hg higher; P < .001). The interaction term of higher SD of blood pressure and higher mean intraocular pressure was associated with faster annual mean deviation changes for both mean arterial pressure (0.01 [95% CI, 0.00-0.02] μm per 1-mm Hg higher; P = .003) and diastolic arterial pressure (0.01 [95% CI, 0.00-0.01] μm per 1-mm Hg higher; P = .001).Conclusions and RelevanceIn this cohort study, higher mean blood pressure and higher SD of blood pressure were associated with faster VF progression. These findings suggest that long-term variability of blood pressure may be a modifier of the association between intraocular pressure and VF progression in glaucoma.

Analytical study on deposits of the aircraft engine piston

Purpose This study aims to provide data references for deposit cleaning, fuel formulation and lubricant formulation. Design/methodology/approach The engine disassembly procedure was carried out based on the IO540 operation manual part number 60297-10-1-7 document. Except for the normal disassembly and assembly of the engine and the measurement of parts, the main test contents included break-in run operation, cylinder pressure test, oil consumption run, pretest calibration run, post-test calibration test and the most critical endurance test. The Lycoming IO-540-V4V5 engine and the customized Hartzell CK319 propeller were selected for the test run. Findings The deposits were mainly composed of C, O, B, Al, Br and Pb, which were mainly sourced from fuel, lubricating oil and body materials. XPS analysis showed that the presence of O determined the richness of the deposit components, giving the deposit structure with organic and inorganic components. Originality/value This work provides certain data support and reference for subsequent aircraft maintenance, fuel formula and lubricating oil formula. The long-term stability and safety of the aircraft run can be ensured through continuous research, improvement and optimizing the operating of the engine. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0300/

Application of thermodynamic equilibrium modelling to predict slagging and fouling tendencies of bituminous coal and wheat straw blends

The combustion or co-combustion of biomass or alternative fuels is important in the energy sector because of the need to reduce the share of fossil fuels. This article is a continuation of previous studies on the behaviour of the mineral matter of selected fuels during the sintering processes. The blends of wheat straw biomass from Polish crops (WS) with bituminous coal from the Makoszowa mine (BC) were studied. The study included proximate and ultimate analysis and oxide analysis of ash blends with the following composition: 10wt% WS/90wt%BC, 25wt% WS/75wt%BC and 50wt% WS/50wt%BC. Based on the oxide content, a prediction (using FactSage 8.0 software) of the sintering process of the mixtures tested. The following parameters were determined: slag phase content, specific heat at constant pressure, and ash density. The fracture stresses tests were carried out using the mechanical test. Pressure tests were also performed using the pressure drop test method. The test results of all test methods used were compared with each other. On the basis of this comparison, a clear correlation was found between the sintering temperatures determined by the mechanical method and the pressure drop method and the physical properties of the ashes, such as density and heat capacity, as well as the chemical properties, i.e. the content of the slag phase. The results of the presented research are a valuable addition to the previous work of the authors. The goal of this work is to develop a precise and measurably simple method to determine the sintering temperature of ashes. This is an extremely important issue, especially in the case of the need to use a wide range of fuels in the energy industry.

Proprioceptive Training Improves Postural Stability and Reduces Pain in Cervicogenic Headache Patients: A Randomized Clinical Trial

Background: Headache is one of the leading causes of disability in the world. Neck proprioception, pain, and postural control are interconnected in both healthy individuals and those with chronic neck pain. This study examines the effects of proprioceptive training using a gaze direction recognition task on postural stability and pain in cervicogenic headache patients. Methods: Patients with cervicogenic headache (n = 34, age: 35–49 y) were randomized into a control group (CON), receiving only selected physical therapy rehabilitation or to an experimental group (EXP), performing proprioceptive training using a gaze direction recognition task plus selected physical therapy rehabilitation. Both programs consisted of 24, 60 min long sessions over 8 weeks. Postural stability was assessed by the modified clinical test of sensory integration of balance (mCTSIB) and a center of pressure test (COP) using the HUMAC balance system. Neck pain was assessed by a visual analog scale. Results: In all six tests, there was a time main effect (p < 0.001). In three of the six tests, there were group by time interactions so that EXP vs. CON improved more in postural stability measured while standing on foam with eyes closed normalized to population norms, COP velocity, and headache (all p ≤ 0.006). There was an association between the percent changes in standing on foam with eyes closed normalized to population norms and percent changes in COP velocity (r = 0.48, p = 0.004, n = 34) and between percent changes in COP velocity and percent changes in headache (r = 0.44, p = 0.008, n = 34). Conclusions: While we did not examine the underlying mechanisms, proprioceptive training in the form of a gaze direction recognition task can improve selected measures of postural stability, standing balance, and pain in cervicogenic headache patients.

Real-Time Accuracy Evaluation of Arterial Catheter Transducer Systems

IntroductionArterial pressure is currently monitored in ICU with a catheter–transducer fluid line. This fluid filled tubing line distorts the original waveform due to its dynamic characteristics (natural frequency, Fn, and damping coefficient, z), introducing potentially significant errors when calculating the cardiac output from pulse contour signal analysis. MethodsIn our study, we cross-compared Fn and z obtained with our new Fast External Pressure Test (FEPT) and with the Fast Flush Test (FFLT), to the reference technique (Sine wave variable Frequency Analysis Test - SFAT). It was carried on a testbench for 48 hours. Fn and z were measured using the three techniques with two fluid-filled tubing lines (standard, STD, and blood conserving device, BCD). ResultsFn measurements with FEPT and FFLT present similar biases (0.79 vs 0.83 Hz), but lower variability for FEPT, with limits of agreement (LOA) ranging from −3.35 to +4.99 Hz for FFLT vs −2.29 to +3.86 Hz (p<0.0001) for FEPT. For the measurement of z, FEPT has a bias of 0.047 and LOA of −0.063 to +0.157, much lower (p<0.0001) than those measured with the FFLT (bias 0.139 and LOA −0.028 to +0.306). ConclusionWhen automated, the FEPT method will detect potential situations of over/under estimations occurrences. This will prevent false alarms, alarm fatigue and therefore consequences on patient care. Eventually, FEPT turns to be more accurate than FFLT, less scattered, less time-consuming, less invasive and so well suited for use in clinical settings.

Validation of digital cardiovascular risk score (DiCAVA) in the United States All of Us dataset

Abstract Introduction The cardiovascular disease (CVD) risk score DiCAVA was developed in 2021 using UK Biobank data with the aim to be used for population health screening by deriving its predictions only from variables readily available to every individual, omitting difficult-to-obtain measurements such as blood pressure and invasive blood tests for metrics like cholesterol or HbA1c, which are commonly used in clinical CVD risk assessment tools. The original set of variables was reduced to 30 in the DiCAVA Lite score to further improve usability in a digital solution accessible to the general population, while maintaining its discrimination ability. Purpose Like many countries, the US has a large burden of CVD and would benefit from easily accessible screening tools. However, to ensure generalisability of the UK-developed score, it is necessary to evaluate its performance in a population where the score is intended to be used. Methods Data from a large real-world modern observational study in the US, All of Us, was used to evaluate discrimination and calibration metrics of the risk score. Participants with pre-existing CVD and without available electronic health records were excluded from the study. Variables from the All of Us dataset were matched to the original variables and any missing values were imputed using multiple imputation. Results 216,985 participants with a median follow-up time of 3.44 years were included in the study. The median age was 51 years and 63% of the population were female. Discrimination ability in the All of Us dataset (C-index 0.76) slightly surpassed the discrimination achieved at training with UK Biobank (C-index 0.73), and that of Framingham risk score calculated for the All of Us population (C-index 0.72), demonstrating the score’s usability in the US. The score showed very good discrimination in both males (C-index 0.74) and females (C-index 0.77), all ethnic groups and age groups, with the exception of the population over 65 years of age, where the C-index dropped to 0.65 as expected (similar to that observed in the UK Biobank). Calibration of the original model was assessed at 3 years and showed under-estimation of the predicted risk (calibration-in-the-large of 2.37%). Following re-calibration, the algorithm demonstrated excellent results with the average predicted 3-year risk showing 0.59% difference from the observed CVD rate (calibration plot in Figure). Conclusions Overall, the DiCAVA Lite score has shown very good discrimination in the US, showing its generalisability in different demographic populations. Its re-calibrated form is now validated for use in the US population and because of its ability to be utilised outside clinical settings, it can be deployed widely in the general population as an initial screening tool and potentially boost awareness of cardiovascular health in an effort to drive preventative care of CVD.Re-calibration of the DiCAVA Lite score

Arterial-myocardial coupling in primary AL amyloidosis. A validation study of vascular involvement

Abstract Background Primary AL amyloidosis is a rare yet lethal systemic disorder. Previously published own and others’ work indicated that vascular involvement in AL cardiac amyloidosis defined as low blood pressure or paradoxical vasodilation may independently affect survival. Mechanistic data will pave the way to validate the clinical role of vascular involvement in these patients. Purpose We sought to explore the presence of arterial-myocardial coupling in AL amyloidosis by investigating associations between markers of vascular and cardiac involvement. Methods We consecutively recruited n=152 newly diagnosed patients with AL amyloidosis that underwent thorough vascular examination including reactive vasodilation (flow mediated vasodilation, FMD and vasodilation in response to cold-pressor test) using high resolution ultrasonography. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (PWV) and aortic pressures and markers of arterial wave reflections were estimated using radial artery tonometry. In a subgroup of patients, transthoracic echocardiography (n=152) and cardiac magnetic resonance (CMR) (n=59) were performed. Results Vascular reactivity correlated with global longitudinal strain (GLS), left ventricle ejection fraction (LVEF)/GLS ratio and worse LV volumes. Vasodilation post-cold pressure test was correlated with LV mass. cSBP exhibited a negative correlation with markers of heart involvement, wall thickness markers, GLS, and CMR tissue characterization markers. A positive correlation between cSBP and LVEF, rotation and twist strain, myocardial work and contractility markers and late gadolinium enhancement (LGE). cDBP was associated with systolic function and contractility markers, with myocardial work indices and LGE. A negative relationship with GLS, LA strain, RV GLS and LA diameter and E/e’ was noted. In addition, T2 was negatively correlated with cDBP. SBP was correlated positively with LVEF, contractility markers, and LGE myocardium and negatively correlated with biomarkers of heart involvement, GLS, CMR structure and tissue characterization. DBP was positively correlated with LGE and myocardial work. A negative relation with NTproBNP, E/e’, RVSP, LA diameter and T2 mapping was noted. Time of wave reflections (Tr) was negatively correlated with rotation strain and positively correlated with circumferential strain, LA strain and LV structure. Ai@75 was positively correlated with myocardial work and contractility markers, and LGE. Ai@75 was negatively correlated with markers of heart involvement, LV structure, E/e’, worse GLS and adverse CMR tissue characterization. Conclusion Markers of peripheral vascular dysfunction were associated with cardiac structure and function acquired both with echocardiography and CMR in AL amyloidosis. This arterial-myocardial coupling supports the clinical role of peripheral vascular involvement in this disease and warrants further investigation.

Pemeriksaan Golongan Darah pada Anak dan Pemeriksaan Gula Darah pada Kelompok Usia Lanjut di Gereja Katolik Santu Petrus Pariti Kabupaten Kupang Tahun 2024

This community service activity was conducted at the Catholic Church of Santu Petrus Pariti, Kupang Regency, involving 124 participants for blood type examinations and 69 participants for blood pressure and glucose level tests. The event began with a retreat by the Medical Laboratory Technology students aimed at raising community awareness about health. A positive response was observed through the enthusiasm of the community, who actively asked questions, indicating that they gained new knowledge related to health examinations. In blood type examinations conducted at TK Santa Maria Pariti and SEKAMI, it was found that among 18 female and 22 male children, 5 participants had blood type A, 15 had blood type B, 17 had blood type O, and 1 had blood type AB. Additionally, glucose level tests revealed that 4 participants had normal glucose levels, while 65 had abnormal levels. Blood pressure tests among the elderly showed 16 with abnormal readings and 53 with normal readings. The examination results provided an initial overview of the health status of the local community, highlighting variations in blood types, glucose levels, and blood pressure conditions. This activity is expected to enhance awareness of the importance of regular health check-ups among the community.

Research on orthotropic anisotropy characteristics of thick bedded limestone based on in situ deformation tests

The orthotropic anisotropy of sedimentary rocks has a significant impact on the force and deformation behavior of the project. In this paper, radial pressurization tests were carried out in the borehole in a typical northern karst area to obtain the deformation properties and orthotropic anisotropy of the rock masses. The test results showed that the deformation modulus and elastic modulus of the limestone rocks in the dam site area obeyed normal distribution. The deformation modulus was basically larger than the proposed deformation modulus of Class II rocks (10 GPa). The deformation behavior and anisotropy degree of the limestone showed a weak correlation with the elevation, but a strong correlation with the development density of the rock joints. The larger development density of the rock in the right bank test section leads to a larger degree of orthotropic anisotropy and frequency of occurrence.

Crack evolution and fractal characteristics of fractured red sandstone based on acoustic emission parameters

Rock is a widely used engineering material, and accurate understanding of its internal microcrack evolution process during loading can provide a theoretical basis for preventing instability and failure in rock engineering. The rock pressure test system and acoustic emission equipment were used to carry out uniaxial loading and acoustic emission monitoring tests on fractured red sandstone. Based on the RA and AF values of acoustic emission and the fractal theory, the internal crack patterns and evolution rules of red sandstone with different crack angles were explored. The results show that the compressive strength of red sandstone varies with the crack Angle in the shape of “U”, and there is an obvious stress drop after the elastic stage of 30° and 45° crack red sandstone, which has a good correspondence with the acoustic emission ringing count rate. During the loading process, the damage mainly caused by tension cracks first appears inside the rock, and then the tension cracks increase steadily and the shear cracks gradually increase, indicating that the rock enters the stage of fracture instability development. With the development of shear cracks, the peak strength is finally reached and the instability failure occurs. During the loading process of 30° fracture red sandstone, the corresponding stress drop phenomenon of “shear crack group” appears. According to the D/S statistical analysis of different crack samples based on acoustic emission ringing count, the fractal dimension presents a decreasing-rising-decreasing trend with the increase of crack inclination, which corresponds to the change of the complexity of crack development in rock.

Factors affecting the syncopal episodes in pediatric vasovagal syncope.

To investigate factors that influence the syncopal episodes in pediatric vasovagal syncope (VVS). A retrospective analysis was performed on the clinical data of 2908 children who were diagnosed with VVS for the first time between January 2001 and February 2023. The study examined the linear relationships among age, sex, height, weight, heart rate (HR), blood pressure, hemodynamic type, and head-up tilt test (HUTT) mode in relation to the onset of syncope. (1) Comparative analysis of intergroup differences revealed statistically significant variations in sex, age, height, weight, HR, systolic blood pressure, hemodynamic classification, and HUTT mode among syncopal episodes groups (P < 0.05); (2) Univariate analysis identified age, female, height, weight, VVS-cardioinhibited type (VVS-CI), VVS-mixed type (VVS-M) as potential risk factors for syncope episodes. Conversely, HR and sublingual nitroglycerin HUTT (SNHUT) emerged as potential protective factors against syncope episodes. (3) Multivariate analysis indicated that the frequency of syncope episodes increased by 0.27/0.02 for each unit increase in age/weight. When females compared to males and VVS-CI and VVS-M compared to VVS-vasoinhibited type (VVS-VI), the frequency of syncope episodes increased by 1.36, 0.53, and 0.66 respectively. Furthermore, SNHUT was associated with a reduction in the number of syncope episodes by 0.34 relative to basic HUTT. Female, age, weight, VVS-CI, and VVS-M were identified as independent risk factors for syncopal episodes, while SNHUT was recognized as an independent protective factor against syncopal episodes.

Research on Optimal Control of Treadmill Shock Absorption Based on Ground Reaction Force Constraint

Research shows that treadmill shock-absorbing devices can reduce the impact of ground reaction forces on the knee and ankle joints during running. Most existing treadmills use fixed or passive shock absorption, meaning their shock-absorbing systems do not actively adjust to changes in ground reaction forces (GRFs). Methods: This study establishes a mathematical model integrating human motion biomechanics and treadmill running surfaces, analyzing the relationships between various parameters affecting the system. Ultimately, an optimal shock-absorbing treadmill control system is designed, utilizing a microcontroller as the main control unit, airbags for shock absorption, and a widely used foot pressure testing system. Objective: The goal is to more effectively prevent running injuries caused by excessive foot pressure. Compared to conventional shock absorption systems, this design features an active multilevel adjustment function with higher precision in regulation. Results: The experimental results demonstrate that the ground reaction force (GRF) generated by the optimal shock-absorbing treadmill control system is reduced by up to 10% compared to that of a conventional shock-absorbing treadmill. Conclusions: This leads to a smaller impact force on the knees due to foot pressure, resulting in better injury prevention outcomes.

Strengthening Transformer Tank Structural Integrity through Economic Stiffener Design Configurations Using Computational Analysis

Power transformers play a vital role in adjusting voltage levels during transmission. This study focuses on optimizing the structural design of power transformer tanks, particularly high-voltage (HV) tank walls, to enhance their mechanical robustness, performance, and operational reliability. This research investigates various stiffener designs and their impact on stress distribution and deformation through finite element analysis (FEA). Ten different configurations of stiffeners, including thickness, width, type, and position variations, were evaluated to identify the optimal design that minimizes stress and deflection while considering weight constraints. The results indicate that specific configurations, particularly those incorporating 16 mm thick H beams, significantly enhance structural integrity. Experimental validation through pressure testing corroborated the simulation findings, ensuring the practical applicability of the optimized designs. This study’s findings have implications for enhancing the longevity and reliability of power transformers, ultimately contributing to more efficient and resilient power transmission systems.

Respiratory failure and rhabdomyolysis caused by severe hypokalemia in a young female with hypertension: a rare critical condition in primary aldosteronism

BackgroundThe two classic manifestations of primary aldosteronism are hypertension and hypokalemia. However, acute respiratory failure due to hypokalemia in primary hyperaldosteronism is rare.Case presentationThe patient was a 27-year-old female who presented with drowsiness and weakness in all extremities. She had been diagnosed with hypertension three years prior, with irregular follow-up, and had a history of preeclampsia one year later. She exhibited high blood pressure and severe hypokalemia (2 mEq/L), leading to respiratory depression and impending respiratory arrest. Consequently, the patient was intubated and transferred to the intensive care unit (ICU). She also developed rhabdomyolysis. Blood pressure tests, including hormonal tests (aldosterone: 13.2 ng/dL, plasma renin activity: 0.32 ng/mL/h), were conducted. Due to the high aldosterone-renin ratio, an abdominopelvic computed tomography (CT) scan was performed. The CT scan revealed a 14 × 12 mm round mass with a washout value above 60%, consistent with an adrenal adenoma, leading to a diagnosis of primary aldosteronism. The patient was discharged after stabilization, and one and a half months after ICU admission, a laparoscopic left adrenalectomy was successfully performed without post-operative complications. Histopathology showed encapsulated hypertrophy of the adrenal cortex with a predominance of large clear cells, confirming the diagnosis of adrenal adenoma. At the most recent follow-up, the patient had normal potassium levels, was normotensive without any medications, and exhibited no alarming signs or symptoms.ConclusionRespiratory depression to the extent of impending respiratory failure and rhabdomyolysis as a result of hypokalemia in primary aldosteronism are extremely rare. In this patient, who developed respiratory depression due to resistant hypokalemia, timely investigation of secondary causes and diagnosis of adrenal adenoma were crucial. The surgery provided definitive treatment for the patient’s blood pressure and prevented the recurrence of life-threatening complications.

Mechanical properties of lander bionic buffer structure based on additive manufacturing

In order to meet the energy absorption requirements of the landing buffer, this paper starts with the buffer filling material of the buffer, draws on the Kelvin structure and spiral structure, and applies the engineering bionics principle to design and establish two structural models: a soccerball-like bionic structure and a multi-spiral bionic structure. Considering the energy absorption and reusability requirements of the lander buffer structure, the bionic structure sample is prepared by additive manufacturing technology and NiTi alloy with shape memory effect. The mechanical properties, energy absorption and recoverability of the sample are analyzed and verified by simulation and experiment. The results show that the accuracy of the numerical simulation is verified by comparing the force-displacement curves of the simulation test and the isometric static pressure test; the multi-spiral bionic structure has better mechanical properties, and its maximum energy absorption is 3096.23 J; the recovery rates of the two structures are as high as 98.02%and respectively 97.12%, and the recovery rate of the soccerball-like bionic structure is slightly higher. This study uses additive manufacturing to prepare the leg-type lander buffer bionic structure, which provides a reference for the bionic design of the lander buffer structure.

Function-based risk reduction intervention for lifestyle-related disorders among inactive 40-year-old people: a pilot randomised controlled trial

Background Interventions for preventing or reducing the development of lifestyle-related disorders should be investigated as these conditions are becoming increasingly prevalent and having large effects on quality of life and life expectancy globally. The aim of this pilot study was to prepare for a full-scale randomised controlled trial by evaluating the short-term changes resulting from a function-based preventive intervention aimed at lifestyle-related disorders on a small group of physically inactive 40-year-old people. Change in objectively measured physical activity, functional capacity according to a risk profile, and goal attainment were main outcomes.MethodsParticipants (n = 27) underwent functional examinations including tests of fitness, strength, mobility, balance, and posture as well as standard medical examinations including weight measures, blood pressure and blood tests and were randomised to two groups. The intervention group (n = 15) received feedback from all the examinations and lifestyle counselling based on a functional profile. The control group (n = 12) received feedback only from the standard medical examination. Follow-up was at 3–4 months. Changes in physical activity measured with accelerometers, functional levels on the functional profile, goal attainment and subjective assessments of health-related quality of life, motivation, function, and physical activity were examined, as were standard medical parameters.ResultsChange in mean time in moderate or more intense physical activity was 9 min higher in the intervention group (95% confidence interval -6.35, 24.51) and change in sedentary time was 42 min lower (-95.24, 11.32). The intervention group showed a higher increase in motivation for change 1.58 on 10-point scale (0.20, 2.97) and indicated more improvement on the functional risk levels concerning fitness (-0.06, 0.90). Correlation between objectively measured and self-assessed physical activity and function increased after the intervention. Most participants in the intervention group achieved some or all of their goals.ConclusionsThis small-scale pilot intervention with functional examinations and lifestyle counselling showed positive tendencies for change in short-term physical activity level. It seemed to lead to better understanding of personal functional capacity and increased motivation for lifestyle changes. Setting and fulfilling meaningful goals for lifestyle-related changes seemed to influence levels on the functional profile in positive directions. Research on larger and more diverse populations will be necessary to better understand the implications of the intervention.Trial registrationClinicalTrials.gov: NCT05535296 first posted on 10/09/2022.

Highly robust electronic skin for object recognition of robot hand based on carbon nanomaterials and SEBS

When robot hands work in a complex environment, they not only need to sense the objects in contact but also need to respond to remote events before physical contact. In this way, robot hands can make predictions, to better adapt to the complex environment. In this paper, we have designed a flexible sensor array, which integrates a piezoresistive sensor and a capacitive sensor for detecting pressure and proximity direction and distance signals simultaneously. Piezoresistive sensors can detect pressure signals in real-time, and capacitive sensors detect pressure and proximity signals. The sensors are arranged in a patterned array and installed on the robot hand to help the robot hand detect the distance and direction of approaching objects, as well as the shape and size of the grasped objects. To avoid mechanical mismatch, piezoresistive sensors and capacitive sensors are fabricated with the same flexible materials. In addition, after extreme pressure tests, the sensors can still work normally, to ensure that the robot hands can work normally after collision. We also combined the detected signal with machine learning, so that the robot can accurately identify objects of different shapes. In the fruit recognition test, the recognition accuracy reached 90 %.

Finite Element Analysis and Computational Fluid Dynamics for the Flow Control of a Non-Return Multi-Door Reflux Valve

This paper presents a comprehensive analysis of a multi-door check valve using computational fluid dynamics (CFD) and finite element analysis (FEA) to evaluate flow performance under pressure test conditions, with an emphasis on its ability to prevent backflow. Check valves are essential components in various industries, ensuring fluid flow in one direction only while preventing reverse flow. The non-return multi-door reflux valve is increasingly preferred due to its superior backflow prevention, fluid control, and effective flow regulation. Rigorous testing under varying pressure conditions is essential to ensure that these valves perform optimally. This study uses CFD and FEA simulations to evaluate the structural integrity and flow characteristics of the valve, including pressure drop, flow velocity, backflow prevention effectiveness, and flow coefficient. A high-fidelity 3D model was created to simulate the valve’s behavior under various conditions, analyzing the effects of parameters such as the number of doors, their orientation, geometry, and operating conditions. The CFD results demonstrated a significant reduction in backflow and pressure drop across the valve. However, localized turbulence and flow separation near the valve doors, particularly under partially open conditions, have raised concerns about potential wear. The velocity profiles indicated a uniform distribution at full opening with laminar velocity profiles and minimal resistance to flow. The results of the FEA showed that the stresses induced by the fluid forces were below critical levels, with the highest stress concentrations observed around the hinge points of the valve doors. Although the valve structure remained intact under normal operating conditions, some areas may have required reinforcement to ensure long-term durability. Combined CFD and FEA analyses demonstrated that the valve effectively preserves system integrity, prevents backflow, and maintains consistent performance under various pressure and flow conditions. These findings provide valuable insights into design improvements, performance optimization, and enhancing the efficiency and reliability of reflux valve systems in industrial applications.

Evaluation of the Dislodgement Resistance of Traditional Adhesive Posterior Bridges Compared With Adhesive Posterior Bridges Prepared With Standard and Modified Slot-Back Dummies: An In Vitro Study.

Background Bridges with minimal preparation have received great acceptance in recent years. Since their first appearance, they have undergone many types of modifications and improvements. Aim This study aimed to compare three types of minimal preparation bridgesin terms of force required for dislodgement and the type of deformation incurred for each of the abutments and prostheses. Materials and methods The research sample consisted of 36 adhesive bridges divided into three equal groups. The first group contained traditional adhesive bridges prepared from the proximal and lingual surfaces with a thickness of 1 mm, the second group contained adhesive bridges with standard slot-back dummies, and the third group contained adhesive bridges with modified slot-back dummies. Each bridge underwent a pressure test, which was directed from the buccal toward the lingual sideand was inclined to the horizontal plane at an angle of 45°. A one-way analysis of variance (ANOVA) test was conducted with a significance level of 0.05. Results The average dislodgement resistance value in the traditional adhesive bridges group was 480,858 N, with no statistically significant difference from the standard slot-back dummy group (p = 1), for which the average dislodgement resistance value was 486,050 N. The average dislodgement resistance valuein the modified slot-back dummy group was 746,733 N, with a statistically significant difference compared with other study groups (p < 0.05). Conclusion The adhesive bridge with the modified slot-back dummy showed higher dislodgement resistance compared to the traditional adhesive bridge and the adhesive bridge with the slot-back dummy.

Dynamic monitoring of the endothelium function in pregnant women at high risk of preeclampsia during pathogenetic prevention of its development

BACKGROUND: Today, preclinical diagnosis of preeclampsia presents significant difficulties. In widespread practice, it is diagnosed based on existing clinical signs and laboratory and functional research methods. Most of them are invasive and expensive, which makes it difficult to use them in widespread clinical practice for diagnosis and, especially, for monitoring the effectiveness of therapy over the dynamics of the disease. It is known that the pathogenesis of preeclampsia can have two independent development paths, converging in a common resulting link — the formation of endothelial dysfunction. Methods for studying endothelial function include determining markers of its imbalance in blood samples and non-invasive functional tests. Non-invasive diagnosis of endothelial dysfunction using the EndoPAT test allows us to quantify endothelium-mediated changes in vascular tone during 5-minute occlusion of the brachial artery. AIM: The aim of this study was to evaluate the method for determining the endothelium function in the first, second and third trimesters of pregnancy during ongoing pathogenetic prevention of preeclampsia. MATERIALS AND METHODS: This interventional uncontrolled study of the effectiveness of preventing preeclampsia using non-invasive assessment of vascular endothelial dysfunction during pregnancy was conducted at the Research Institute of Obstetrics, Gynecology and Reproductology named after D.O. Ott, St. Petersburg, Russia. The study involved 108 pregnant women at high risk of developing preeclampsia. All pregnant women underwent a cuff test to determine endothelial dysfunction using the peripheral arterial tonometry technique on the Endo-PAT 2000 device. The dynamic study was carried out in the first, second and third trimesters of pregnancy. As a result of the study, when endothelial dysfunction was detected [logarithmic transformation of reactive hyperemia peripheral arterial tonometry index (LnRHI) less 0.51], a complex glycosaminoglycan was additionally added to the basic prophylaxis with acetylsalicylic acid at a dosage of 250 MU (one capsule three times a day for eight weeks), then a cuff test was monitored after 6–12 weeks. Statistical analysis was performed using the IBM SPSS Statistics 20 software. All tests for significance were two-tailed, and differences were considered significant at p 0.05. RESULTS: Endothelial dysfunction was detected in the first trimester in 59 (55%) patients, then during ongoing complex therapy in the second trimester (n = 72) in 46 (64%) patients and in the third trimester (n = 46) in 4 (1%) patients. Moderate preeclampsia in the third trimester (35–39 weeks of gestation) developed in 28 (25.9%) patients out of 108. At the same time, at the start of the study, 15 patients with endothelial dysfunction received complex therapy, and 13 individuals only took acetylsalicylic acid. Among 46 patients who observed the dynamics of the entire pregnancy, only 4 (8.7%) women developed preeclampsia. After complex treatment prescribed based on the first trimester parameters, out of 36 patients who discontinued complex therapy and did not undergo a functional test subsequently, preeclampsia developed in 16 (44.4%) women. In the second trimester, out of 26 patients who stopped complex therapy, preeclampsia developed in 8 (30.8%) people. Thus, constant monitoring and complex therapy reduced the frequency of preeclampsia. In the group with a history of preeclampsia, the disease developed in 13 (39.4%) women. In the group with a high risk of preeclampsia according to the results of combined prenatal screening in the first trimester, with the exception of a history of preeclampsia (blood pressure test, placental growth factor level in the blood serum, lowest uterine artery pulsatility index value calculated to assess the individual risk of preeclampsia with a titer less than 1 : 100), preeclampsia occurred in 4 (13.3%) women. In the group with extragenital pathology associated with the risk of preeclampsia, including obesity, pregestational diabetes mellitus, chronic arterial hypertension, and chronic kidney disease, with the exception of a history of preeclampsia and a high risk of preeclampsia according to the results of perinatal screening, preeclampsia occurred in 11 (24.4%) women. In the high–risk groups for preeclampsia, we identified the highest-risk group, namely, one with the presence of preeclampsia in the anamnesis. CONCLUSIONS: The effectiveness of the functional method for determining endothelial dysfunction in the first, second and third trimesters of pregnancy during pathogenetic prevention of preeclampsia has been proven.