Inverse Linear Relationship Research Articles

Factor XI activity in ST-segment elevation myocardial infarction

Abstract Background ST-segment elevation myocardial infarction (STEMI) is characterized by a significant thrombotic burden, where the coagulation cascade, including Factor XI (FXI) activity, plays a crucial role. In STEMI and other thrombotic conditions, FXI levels vary according to patient characteristics and timing from the event. Understanding the changes in FXI activity may offer valuable insights into the optimal patient selection and timing for use of investigational FXI inhibitors. Purpose Our aim was to characterize variations in FXI activity in STEMI patients. Methods In this prospective, observational study, patients admitted with STEMI underwent two measurements of plasma FXI activity, prior to coronary angiography and at discharge, using the HemosIL assay. The variation in FXI activity at these timepoints was compared between patients with and without coronary thrombus, as detected by an angiographic core-lab. Linear regression analyses were conducted to test the association of candidate predictors with FXI variation between admission and discharge (i.e., presence of coronary thrombus, PCI of the culprit artery, Thrombolysis in Myocardial Infarction flow post-PCI, bailout use of glycoprotein IIb/IIIa inhibitors, time to second measurement of FXI activity) and with FXI value at admission (i.e., age, sex, atrial fibrillation, late [>24 hours] STEMI presentation, presence of coronary thrombus). Results From November 2023 to February 2024, 49 STEMI patients were included. The median variation in FXI activity among admission and discharge was +24.8% (interquartile range [IQR] 11.8; 69.0; p<0.001). This variation was observed in both patients with (+41.6% [IQR 14.3; 74.6]; p<0.001) and without (+21.8% [IQR -2.3;40.7]; p=0.008) thrombus at coronary angiography, with significant interaction effects compared to the global STEMI population (p for interaction <0.001). An inverse linear regression relationship was observed between presence of coronary thrombus and changes in FXI activity (coefficient -33.0, 95% CI -59.5 to -7.2; p=0.012). Furthermore, in the model exploring predictors of FXI activity at admission, thrombus presence (coefficient -40.9, 95% CI -75.3 to -6.4; p=0.024) and subacute presentation (coefficient 90.8, 95% CI 21.9 to 159.8; p=0.015) emerged as significant predictors, albeit with contrasting effects on FXI activity. Figure 1 Conclusions Our findings reveal significant increases in FXI activity from admission to discharge in STEMI patients. The inverse relationship between the presence of coronary thrombus and FXI activity variations, along with the contrasting associations among initial FXI levels and subacute patients’ presentation or thrombus presence, support the importance of FXI in the coagulation process during STEMI. These findings suggest targeted FXI inhibition, especially early in STEMI management, could be beneficial, meriting detailed investigation in future studies.Multivariable linear regression analysis

The inverse relationship between Life’s Essential 8 and risk of metabolic syndrome: evidence from NHANES 2005-2018

BackgroundMetabolic syndrome (MetS) has a close association with cardiovascular diseases. Few studies have investigated the association of Life’s Essential 8 (LE8), the updated measurement of cardiovascular health (CVH), with MetS.MethodsThe National Health and Nutrition Examination Survey (2005–2018) data was extracted. The LE8 comprised 4 health behaviors (diet, physical activity, nicotine exposure, and sleep health) and 4 health factors [body mass index (BMI), blood lipids, blood glucose, and blood pressure (BP)]. The total LE8 score is the average of 8 metric scores (0-100), categorized into low (0–49), moderate (50–79), and high CVH (80–100) levels. Multivariable logistic regression models, restricted cubic spline models and stratified analyses were performed to examine the relationship between LE8 and MetS.ResultsIn this study, a total of 21,543 participants represented 146.6 million non-institutionalized U.S. adults. Following adjustment for various potential covariates, participants who attained a moderate [adjusted odds ratio (AOR) = 0.234, 95% CI: 0.209, 0.262] or a high CVH level (AOR = 0.026, 95% CI: 0.021, 0.032) exhibited an inverse correlation with MetS risks when comparing those with a low CVH level. An inverse linear dose-response relationship between LE8 scores and MetS risks was also identified (P for nonlinearity > 0.05).ConclusionsLE8 was inversely associated with the risk of MetS. Adhering to LE8 guidelines to sustain a higher CVH level may be beneficial for preventing MetS.

Composition and Injection Rate Co-Optimization Method of Supercritical Multicomponent Thermal Fluid Used for Offshore Heavy Oil Thermal Recovery

Supercritical multicomponent thermal fluid injection is a new technology with great potential for offshore heavy oil thermal recovery. In the process of thermal fluid generation, the reaction conditions including temperature, pressure, and the organic mass concentration in the reaction material will significantly affect its composition and injection rate and will further affect the thermal recovery and development quality of heavy oil. However, there is a lack of relevant research on the variation rules and control methods of the composition and injection rate of supercritical multicomponent thermal fluids, resulting in a lack of technical mechanisms for effective optimization. To fill this gap, a reaction molecular dynamics simulation method was used to simulate thermal fluid generation under different temperatures, pressures, and organic mass concentrations. The changes in thermal fluid composition and yield with reaction conditions were studied, and a control model of thermal fluid composition and yield was established. The proportional relationship between the thermal fluid generation scale of an offshore heavy oil platform and the simulated thermal fluid generation scale is analyzed, and a collaborative optimization method of thermal fluid composition and injection rate in field applications is proposed. The results show the following: (1) The higher the mass concentration of organic matter, the higher the content of supercritical carbon dioxide and supercritical nitrogen in thermal fluids, and the lower the content of supercritical water. (2) The higher the temperature and pressure, the higher the thermal fluid yield, and the higher the organic mass concentration, the lower the thermal fluid yield. (3) The component fitting model conforms to the power function relationship, and the coefficient of determination R2 is greater than 0.9; the yield fitting model conforms to the modified inverse linear logarithmic function relationship, the determination coefficient R2 is greater than 0.8, and the fitting degree is high. (4) The ratio between the actual injection rate of thermal fluids in the mine field and the molecular simulated thermal fluid yield is the ratio of organic matter mass in the platform thermal fluid generator and organic matter mass in the simulated box. (5) Based on the composition and yield control model, combined with the simulation of the ratio relationship between yield and injection rate in the field, a collaborative optimization method of thermal fluid composition and injection rate was established. The research results can provide an effective technical method for predicting, controlling, and optimizing the composition and injection rate of supercritical multicomponent thermal fluids.

Влияние малых доз ионизирующего излучения при облучении in vitro на показатели крови

Abstract. The purpose is the determination of the degree of influence of small absorbed doses of ionizing radiation on biochemical and hematological parameters during irradiation of peripheral blood samples of cattle in vitro. For the work, blood samples were taken from lactating cows kept under the influence of the background absorbed dose in the Krasnoyarsk Territory, followed by in vitro irradiation at doses of 5, 50, 500 mGy. Methods. Peripheral blood was taken from blood vessels from the tail vein into vacuum tubes with a coagulation activator, in vitro irradiation of samples was carried out on an installation equipped with a Cs-137 source, biochemical studies of blood serum were carried out using a PE-5400UF spectrophotometer. Hematological blood parameters were determined according to generally accepted methods. Results. Ionizing radiation in vitro in doses of 5 mGy, 50 mGy and 500 mGy of peripheral blood samples of cattle affects hematological parameters in different directions, which is characterized by wave-like fluctuations in hemoglobin values, a decrease in the content of erythrocytes and a decrease in the erythrocyte sedimentation rate. It was found that a single irradiation of peripheral blood samples of cows at a dose of 5 mGy reduced the concentration of beta-globulins and creatinine and did not affect the content of total protein and protein fractions. When exposed to ionizing radiation at a dose of 50 mGy, the content of total protein, the level of beta-globulins, creatinine decreased in blood samples, and the content of albumins and alpha-, gamma-globulins did not change. When irradiated at a dose of 500 mGy, the relative content of alpha-globulins, the concentration of ALT and AST decreased, the content of creatinine, total protein, albumins and beta-, gamma-globulins did not change. The stability of alkaline phosphatase, albumins and gamma globulins to ionizing effects at doses of 5 mGy, 50 mGy and 500 mGy has been established. Scientific novelty. The linear dependence of the concentration of alpha-globulins, AST and ALT on the absorbed dose was revealed, the numerical values of the approximation coefficients describing the decrease in concentration and biochemical parameters were determined. The inverse direct linear relationship between creatinine stability and absorbed dose has been established. Practical significance is the established digital values of the approximation coefficients of alpha globulins, AST and ALT can be used in the reconstruction of radiation dose values in the range of 5–50 mGy.

Transport of a comb-like polymer across a nanochannel subject to a pulling force.

We investigate the dynamics of comb-like polymer translocation through a nanochannel using three-dimensional Langevin dynamics simulations based on a coarse-grained chain model. A comprehensive set of simulations are performed to examine the effects of system parameters such as the grafting densityρof the side chains, the polymer chain length, the nanochannel dimensions, and the magnitude of the pulling force on the translocation dynamics. For a given polymer chain length, keeping the backbone length is constant while varyingρ, we have found that the dependence of the mean translocation time⟨τ⟩onρis non-monotonic, with a maximum translocation time for a specificρat which the translocation is the slowest. The simulation results also show that⟨τ⟩is not significantly affected by the channel width above a certain radius, while the comb-like polymer translocation is hindered by a narrower channel due to increased interactions between the chain monomers and the channel. In addition,⟨τ⟩increases linearly with the nanochannel length. A linear scaling relationship between the mean translocation time⟨τ⟩and the chain lengthNof polymer is obtained,⟨τ⟩∼N. Similarly, the dependence of⟨τ⟩on the backbone chain sizeNbbhas a quasi-linear dependence,⟨τ⟩∼Nbb. On the other hand, the translocation velocityvfollows a power-law relationship with the polymer chain lengthNasv∼N-1. The mean translocation time also shows an inverse linear relationship with the magnitude of the pulling forceF,⟨τ⟩∼F-1. The power-law relationships discovered in this study contribute to the fundamental understanding of the comb polymer translocation dynamics and to establishing a framework for further investigations in this field.

Experimental Study on Submerged Nozzle Damping Characteristics of Solid Rocket Motor

Acoustic instabilities in solid rocket motors (SRMs) can lead to severe performance deterioration and structural damage. Nozzle damping accounts for the main acoustic dissipation source, and it is highly dependent on geometric parameters and operating conditions. This study experimentally investigated the acoustic damping characteristics of submerged nozzles in SRMs, focusing on the effects of submerged cavity dimensions, nozzle convergent angle, throat-to-port area ratio, and mean pressure variations on the longitudinal instability. The steady-state wave decay method was used to quantify the acoustic damping, and a designed rotary valve system was employed to introduce periodic pressure oscillations in the high-pressure combustion chamber. The results revealed that a larger submerged cavity would reduce the nozzle damping efficiency, with the elimination of the submerged cavity enhancing the nozzle decay coefficient magnitude by 41.9%. Furthermore, increasing the nozzle convergent angle was found to amplify acoustic wave reflection, thereby diminishing damping performance. A linear inverse relationship was observed between the throat-to-port area ratio and the decay coefficient, with a 125% increase in the ratio resulting in a 24.3% reduction in the decay coefficient. Interestingly, despite the formation of complex vortices in the submerged cavity, the mean pressure variation presented negligible effects on acoustic damping characteristics, and its damping performance is similar to a simple nozzle without a cavity. These findings provide valuable experimental data for predicting the stability of a solid rocket motor with a submerged nozzle and offer insights into the optimization of submerged nozzle designs for higher acoustic damping in SRMs.

Association between dietary vitamin C intake and migraine in adults: A cross-sectional study of the National Health and Nutrition Examination Survey.

Previous studies indicate that vitamin C may decrease the occurrence and intensity of migraines, but the evidence is restricted due to small sample sizes. This study aimed to determine the magnitude of the association between dietary vitamin C intake and migraine in the general population. This cross-sectional study utilised data from the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2004. Participants who had severe headaches or migraines in the past 3 months were classified as experiencing migraines. Dietary vitamin C intake was evaluated using the 24-h dietary recall system. Logistic regression models, restricted cubic spline (RCS) regression and stratified analyses were employed to assess the association between dietary vitamin C intake and migraine. The study included 4101 participants, of whom 702 (17.12%) experienced migraine. The study revealed an inverse association between dietary vitamin C intake and migraine (odds ratio [OR] = 0.89, 95% confidence intervals [CI] = 0.83-0.96, p = 0.002) after adjusting for demographic covariates, lifestyle covariates, laboratory tests, physical examinations, physical activity, dietary covariates and comorbidities. When vitamin C intake was categorised, the adjusted OR (95% CI) for migraine in Q4 (highest vitamin C intake) was 0.64 (95% CI = 0.49-0.84, p = 0.001) compared to Q1 (lowest vitamin C intake). The RCS regression showed a linear inverse relationship between dietary vitamin C intake and migraine (pnon-linearity = 0.449). The findings remained consistent, and no significant interactions were found among different groups. Dietary vitamin C intake was inversely associated with migraine, and a linear negative relationship was found between vitamin C intake and migraine.

Fast determination of thermal conductivity of aluminum alloy by laser-induced breakdown spectroscopy

Abstract The matrix thermal properties are closely linked to laser-induced plasma, because it is the heat effect predominantly governs the process when the nanosecond-pulsed laser acting on the material, particularly in metallic materials. In the study using a series of pure metal samples, We detected a substantial inverse linear relationship linking the matrix’s thermal storage coefficient of the material to the temperature of the plasma. This discovery reveals that metals exhibiting reduced thermal conductivity or lower specific heat capacity necessitate a smaller amount of laser energy to achieve thermal spreading and to facilitate the transitions to the melted and vaporized states, which consequently results in a higher rate of material removal and higher plasma temperatures. Based on this correlation, a prediction model for the thermal conductivity of aluminum alloys has been developed, employing LIBS technique as analysis method, alongside PLS regression, with a relative error of below 1.5%. It presents a pioneering technique for the swift evaluation of thermal conductivity in aluminum alloys.

Associations between Life's Essential 8 and risks of all-cause and cardiovascular mortality in cancer survivors: A prospective cohort study from NHANES

BackgroundLife's Essential 8 (LE8), an indicator of cardiovascular health (CVH), can predict overall and cardiovascular mortality in the general population. Considering that cancer survivors have a higher risk of cardiovascular disease (CVD), our study aimed to investigate the association between LE8 and the prognosis of cancer survivors. MethodsA total of 2191 cancer survivors were included from the National Health and Nutrition Examination Survey (2005–2018). LE8 scores, derived from eight individual metrics, were categorized into three groups: low (0–49), moderate (50–79), and high (80–100). Cox regression analysis, nonlinear analysis, sensitivity analysis, and subgroup analysis were conducted to explore the association between LE8 scores and mortality risks, adjusting for potential confounders. ResultsDuring a median follow-up of six years, 479 deaths were recorded, including 118 CVD events and 156 cancer events. LE8 scores showed an inverse linear relationship with all-cause and cardiovascular mortality. A 10-point increase in LE8 scores was associated with a 25 % reduction in all-cause mortality (hazard ratio [HR], 0.75; 95 % CI, 0.66–0.85) and a 29 % reduction in cardiovascular mortality (HR, 0.71; 95 % CI, 0.57–0.89). Additionally, moderate CVH was linked to a lower risk of all-cause mortality (HR, 0.55; 95 % CI, 0.37–0.81), while high CVH was associated with an even lower risk (HR, 0.35; 95 % CI, 0.19–0.68). Similarly, moderate CVH demonstrated a decreased risk of cardiovascular mortality (HR, 0.31; 95 % CI, 0.15–0.63), with high CVH showing an even lower risk (HR, 0.23; 95 % CI, 0.09–0.58). However, LE8 scores was not associated with cancer-specific mortality. ConclusionsA higher LE8 score was independently associated with a decreased risk of both all-cause and cardiovascular mortality in cancer survivors, underscoring the significance of optimizing CVH during the survivorship phase of cancer care.

Corticosteroid therapy for nephrotic syndrome in children.

In nephrotic syndrome protein leaks from the blood to the urine through the glomeruli resulting in hypoproteinaemia and generalised oedema. Children with untreated nephrotic syndrome frequently die from infections. The majority of children with nephrotic syndrome respond to corticosteroids. However about 70% of children experience a relapsing course with recurrent episodes of oedema and proteinuria. Corticosteroid usage has reduced the mortality rate in childhood nephrotic syndrome to around 3%, with infection remaining the most important cause of death. However corticosteroids have known adverse effects such as obesity, poor growth, hypertension, diabetes mellitus, osteoporosis and adrenal suppression. The original treatment schedules for childhood nephrotic syndrome were developed in an ad hoc manner. The optimal doses and durations of corticosteroid therapy that are most beneficial and least harmful have not been clarified. The aim of this review was to determine the benefits and harms of different corticosteroid regimens in preventing relapse in children with steroid sensitive nephrotic syndrome (SSNS). We searched the Cochrane Controlled Trials Register (Cochrane Library, Issue 2, 2002), Cochrane Renal Group Specialised Register (July 2002), MEDLINE (1966 - July 2002) and EMBASE (1980 - July 2002) without language restriction, reference lists of articles, abstracts from conference proceedings and contact with known investigators in the area. Randomised controlled trials were included if they were carried out in children (aged three months to 18 years) in their initial or subsequent episode of SSNS, if they compared different durations, total doses or other dose strategies using prednisone or other corticosteroid agent and if they had outcome data at six months or more. Two reviewers independently reviewed all eligible studies for inclusion, assessed study quality and extracted data. The principle outcome measure was the number of children with and without relapse after six and 12-24 months. Secondary outcomes sought included the number of children who developed frequently relapsing nephrotic syndrome and adverse events. A random effects model was used to estimate summary effect measures (relative risk (RR), risk difference (RD)) after testing for heterogeneity. Meta-regression was used to explore potential between-study differences due to the baseline risk of relapse, study quality and types of interventions used. Nineteen trials have been included in this review. A meta-analysis of six trials, which compared two months of prednisone with three months or more in the first episode, showed that the longer duration significantly reduced the risk of relapse at 12 - 24 months (RR 0.70; 95% CI 0.58 to 0.84) without an increase in adverse events. There was an inverse linear relationship between the duration of treatment and risk of relapse (RR = 1.26 - 0.112 duration; r(2) = 0.56; p = 0.03). The number of children who became frequent relapsers and the mean relapse rate/patient/year were also significantly reduced without increase in serious adverse events. In children with frequently relapsing nephrotic syndrome, deflazacort was significantly more effective in maintaining remission than prednisone (RR 0.44; 95% CI 0.25 to 0.78). Children in their first episode of SSNS should be treated for at least three months with an increase in benefit being demonstrated for up to seven months of treatment. In a population with a baseline risk for relapse following the first episode of 60% with two months of prednisone, daily prednisone for four weeks followed by alternate day therapy for six months would be expected to reduce the number of children experiencing a relapse by about 33%. In children who relapse frequently, deflazacort deserves further study.

Synphytoindication models of the anthropogenic transformation of ecosystems

Human activity related to the exploitation or protection of environmental elements requires the creation of forecasts of the consequences involved. Such forecasts are not possible without the construction of models of ecosystems and the processes occurring in them. One of the critical elements in modern forecasting of the dynamics of ecosystems is the modelling of their anthropogenic block. Our research aims to develop methods for assessing the anthropogenic transformation of ecosystems necessary for modelling their state and dynamics. In accordance with the goal, we set ourselves the following tasks: to determine the limits of anthropotolerance of plant species; to evaluate the hemeroby of plant groups by the methods of synphytoindication; to create models of mutual dependence between anthropogenic transformation and natural dynamics. To implement the tasks, we used standard geobotanical methods (creating a geobotanical description, classification of plant communities, and synphytoindication). Hemeroby of plant communities can be used as an indicator of the anthropogenic transformation of ecosystems. To do this, we measure the boundaries of anthropotolerance of the plant species that make up these groupings. The range of anthropotolerance of individual plant species can be determined by the 12 most common types of human activity. The strength of their impact on ecosystems was determined by the induced changes in above-ground phytomass. The transition from anthropotolerance of individual species to hemeroby of plant communities was carried out according to the classical synphytoindication technique. We created an 18-point scale by assigning three points to each classic type of hemoroby. The use of the synphytoindication scale allows modelling of the interdependence between anthropogenic transformation and the measurable characteristics of the ecosystem. An inverse linear relationship with a probability of approximation of 0.2 and a correlation coefficient of 0.45 is an indicator of natural dynamics and the level of anthropogenic transformation. The correlation coefficient is 0.29 for ecosystems that are not suitable for economic use, and 0.85 for the rest.

Study changes in insulin secretion depending on anthropometric, anamnestic and laboratory parameters using a univariate linear model

Insulin is a peptide hormone which is produced by β-cells of the pancreas. It is difficult to underestimate the effect of insulin, it has a significant impact on organs and systems. Insulin is a carbohydrate “conductor”, disorders of the regulation process of which lead to metabolic disorders and irreversible changes in the human body.Insulin resistance (IR) is a state of reduced response of tissues to the action of insulin, which leads to disorders, including the reproductive function of a woman. Long-term IR leads to the development of hyperandrogenism, as a result of which anovulatory cycles, hirsutism, skin problems, vaginal dysbiosis, and an increased rate of anxiety and depression.The objective: to determine the influence of anthropometric, anamnestic and laboratory indicators on insulin secretion before and after a load of 75 g of glucose.Materials and methods. The study included 82 women of early reproductive age. 52 women are involved in the main group, 30 women – in the control group. The patients signed an informed voluntary consent, and the main aspects of the study were explained to them. In the course of the research we developed a questionnaire and conducted a survey.Anthropometric parameters (height, body weight, waist circumference) were measured, and BMI was calculated. Laboratory indicators were studied: luteinizing hormone (LH), follicle-stimulating hormone (FSH), sex hormone binding globulin (SHBG), thyroid-stimulating hormone (TSH), prolactin, dehydroepiandrosterone-sulfate (DHEA-S), total testosterone, free testosterone index, HOMA-IR index, glucose tolerance test (GTT) + determination of insulin level, Matsuda index.Results. The conducted correlation analysis proved the relationship between the level of fasting insulin and the following indicators: WC – r = 0.321900051, BMI – r = 0.333470666, establishment of the menstrual cycle – r = -0.283517408, duration of bleeding during menstruation, TSH level – r = 0.249578215, DHEA-S – r = -0.209053013, total testosterone level – r = 0.278921593.A relationship was found between the level of insulin after a load of 75 g of glucose and the following indicators: body weight at the birth of female respondents – r = -0.238495649, gestational term of birth – r = -0.243025226, FSH level – r = 0.291379519.Conclusions. A small positive (direct) relationship was determined between the fasting insulin level and the following indicators: WC, BMI, TSH level, and total testosterone level. An increase of these indicators is associated with an increase in fasting insulin level. A slight inverse linear relationship was found between the level of fasting insulin and the duration of menstrual function, the duration of bleeding during menstruation and the DHEA-S level.A slight inverse relationship is observed between the level of insulin after load and body weight at birth, the term of birth. Lower birth weight and early gestational age are associated with increased insulin levels after load.There is a direct relationship between post-load insulin levels and FSH levels. An increased FSH concentration will lead to a rise of insulin level after load.

Meteorological factors and risk of ischemic stroke, intracranial hemorrhage, and subarachnoid hemorrhage: A time-stratified case-crossover study.

Stroke risks associated with rapid climate change remain controversial due to a paucity of evidence. To examine the risk of subarachnoid hemorrhage (SAH), intracranial hemorrhage (ICH), and ischemic stroke (IS) associated with meteorological parameters. In this time-stratified case-crossover study, adult patients hospitalized for their first stroke between 2011 and 2020 from the insurance claims data in Taiwan were identified. The hospitalization day was designated as the case period, and three or four control periods were matched by the same day of the week and month of each case period. Daily mean and 24-h variations in ambient temperature, relative humidity, air pressure, and apparent temperature were measured. Conditional logistic regression models were applied to assess the risk of stroke associated with exposure to weather variables, using the third quintile as a reference, controlling for air pollutant levels. There were 7161 patients with SAH, 40,426 patients with ICH, and 107,550 patients with IS. There was an inverse linear relationship between mean daily temperature and apparent temperature with ICH. Elevated mean daily atmospheric pressure was associated with an increased risk of ICH. A greater decrease in apparent temperature over a 24-h period was associated with increased risk of ICH but decreased risk of IS (odds ratio (95% confidence interval) for the first vs. third quintile of changes in apparent temperature, 1.141 (1.053-1.237) and 0.946 (0.899-0.996), respectively). There were considerable differences in short-term associations between meteorological parameters and three main pathological types of strokes. The authors have no permission to share the data.

A Comparative Study of Commercially Available Ultrasound Contrast Agents for Sub-harmonic-Aided Pressure Estimation (SHAPE) in a Bladder Phantom

ObjectiveThe goal of this study was to evaluate the performance of different commercial ultrasound contrast microbubbles (MBs) when measuring bladder phantom pressure with sub-harmonic-aided pressure estimation (SHAPE) methodology. We hypothesized that SHAPE performance is dependent on MB formulation. This study aimed to advance the SHAPE application for bladder pressure measurements in humans. MethodsUsing a previously designed and built bladder phantom, we tested four different commercial agents: Definity, Lumason, Sonazoid and Optison. A standard clinical cystometrogram (CMG) system was used to infuse a MB–saline mixture into the bladder phantom to measure pressure. Ultrasound imaging was performed using the GE Healthcare LOGIQ E10 scanner. ResultsAll agents showed a predicted inverse linear relationship between change in pressure and SHAPE signal. However, they differ from each other in terms of stability, linear correlation, sensitivity to pressure and error. Generally, Definity and Lumason showed the highest performance during the SHAPE-based bladder phantom pressure assessments. ConclusionOur results show that the SHAPE signal decreases as bladder phantom pressures increases, regardless of the agent or CMG phase, suggesting the possibility of using SHAPE for measuring bladder pressure without a catheter. However, the efficacy of SHAPE in measuring pressure varies by MB formulation. These observations support using Lumason and Definity in a human subject feasibility study as we advance toward a catheter-free solution for measuring voiding bladder pressure via SHAPE.

The Effects of Liquid Density and Impeller Size with Volute Clearance on the Performance of Radial Blade Centrifugal Pumps: An Experimental Approach

This study was carried out to experimentally investigate the effect of impeller size with volute clearance and liquid density on the performance of radial blade centrifugal pumps. Three impeller sizes of 121.54mm, 109.38mm and 97.23mm with respective volute clearance of 6mm, 12mm and 18mm were considered, and five different liquid blend which comprise of water, two liquids that are denser than water and two other liquids that are less-dense than water (with respective liquid densities of: 1197 kg/m3 , 1097 kg/m3 , 1000kg/m3 , 898.2 kg/m3 and 798.4 kg/m3 ). In the experimental set-up, the pump flow capacity were varied from 12m3 /hr to 62m3 /hr at interval of 5m3 /hr and the corresponding pump power consumption, attained pump head were recorded and pump efficiency were determined. Microsoft excel was used to evaluate the trend, performance trend was used to develop the pump performance model showing the relationship between the various parameters. The results from the investigation revealed that with the various impeller sizes of 121.54mm, 109.38mm and 97.23mm of respective volute clearance of 6mm, 12mm and 18mm, the attained optimum efficiency were 74.42%, 54.78 and 33.54% respectively at a correspondence optimum pump head of 23.66m, 20.60m and 18.87m. The results also showed that there is a direct relationship between pump power consumption and process liquid density, while showing an inverse linear relationship between the pump instantaneous start up power and impeller diameter. It was therefore concluded among others that liquid with higher density will usually require higher power to initiate and maintain flow at constant flow rate and impeller size. It is then recommended among others that pump designers, application engineers and users of centrifugal pumps should consider possible increase in pump power consumption when working with a process application that has higher tendency for dynamic increase on the process fluid density.

Research on the Influence of Core Sensing Components on the Performance of Galvanic Dissolved Oxygen Sensors.

The galvanic dissolved oxygen sensor finds widespread applications in multiple critical fields due to its high precision and excellent stability. As its core sensing components, the oxygen-permeable membrane, electrode, and electrolyte significantly impact the sensor's performance. To systematically investigate the comprehensive effects of these core sensing components on the performance of galvanic dissolved oxygen sensors, this study selected six types of oxygen-permeable membranes made from two materials (Perfluoroalkoxy Polymer (PFA) and Fluorinated Ethylene Propylene Copolymer (FEP)) with three thicknesses (0.015 mm, 0.03 mm, and 0.05 mm). Additionally, five concentrations of KCl electrolyte were configured, and four different proportions of lead-tin alloy electrodes were chosen. Single-factor and crossover experiments were conducted using the OxyGuard dissolved oxygen sensor as the experimental platform. The experimental results indicate that under the same membrane thickness conditions, PFA membranes provide a higher output voltage compared to FEP membranes. Moreover, the oxygen permeability of FEP membranes is more significantly affected by temperature. Furthermore, the oxygen permeability of the membrane is inversely proportional to its thickness; the thinner the membrane, the better the oxygen permeability, resulting in a corresponding increase in sensor output voltage. When the membrane thickness is reduced from 0.05 mm to 0.015 mm, the sensor output voltage for PFA and FEP membranes increases by 86% and 74.91%, respectively. However, this study also observed that excessively thin membranes might compromise measurement accuracy. In a saturated, dissolved oxygen environment, the sensor output voltage corresponding to the six oxygen-permeable membranes used in the experiment exhibits a highly linear inverse relationship with temperature (correlation coefficient ≥ 98%). Meanwhile, the lead-tin ratio of the electrode and electrolyte concentration have a relatively minor impact on the sensor output voltage, demonstrating good stability at different temperatures (coefficient of variation ≤ 0.78%). In terms of response time, it is directly proportional to the thickness of the oxygen-permeable membrane, especially for PFA membranes. When the thickness increases from 0.015 mm to 0.05 mm, the response time extends by up to 2033.33%. In contrast, the electrode material and electrolyte concentration have a less significant effect on response time. To further validate the practical value of the experimental results, the best-performing combination of core sensing components from the experiments was selected to construct a new dissolved oxygen sensor. A performance comparison test was conducted between this new sensor and the OxyGuard dissolved oxygen sensor. The results showed that both sensors had the same response time (49 s). However, in an anaerobic environment, the OxyGuard sensor demonstrated slightly higher accuracy by 2.44%. This study not only provides a deep analysis of the combined effects of oxygen-permeable membranes, electrodes, and electrolytes on the performance of galvanic dissolved oxygen sensors but also offers scientific evidence and practical guidance for optimizing sensor design.

In-situ pressure differential-accelerated mechanical fatigue testing and modeling of a reinforced fuel cell membrane

Modern polymer electrolyte fuel cells typically use reinforced membranes for improved mechanical durability. Due to costly experimentation, however, the fatigue properties of these membranes remain poorly understood. In this work, we employ the G'Sell-Jonas constitutive material model to investigate the mechanical fatigue response of a reinforced membrane under various environmental conditions in accelerated in-situ test settings. For fatigue evaluation, we utilize a novel pressure differential-accelerated mechanical stress test (ΔP-AMST) of shorter duration (<1 week) than previous AMSTs. The S–N curves constructed from experimental results at variable ΔP and temperature demonstrate inverse linear relationship between logarithmic fatigue lifetime and nominal stress, with greatly enhanced (∼10x) lifetime at reduced temperature. According to the results, a finite element-based fatigue model is developed and validated, which considers the impacts of hygrothermal fluctuations and strain rates. The model shows peak tensile stress during the dry phase at the center of the test section, which is consistent with the expected scenario for in-situ fuel cell membrane fatigue. Through this novel accelerated test and its modeling, it becomes possible to assess the fatigue lifetime of reinforced membranes under variable temperatures, humidity swings, pressure differentials, and swelling properties, in much shorter time than with standard protocols.

Effect of concrete preconditioning method on accelerated carbonation rate

Several methods have been proposed for the accelerated carbonation test of concrete, but there is no consensus on the best procedure for preconditioning the specimens. Thus, this study aims to assess the effects of four preconditioning methods - ISO 1920-12:2015, EN 13295:2004, XP P 18-458:2008 and RILEM TC 116-PDC:1999 - on the accelerated carbonation test. Four different concrete mixtures were used to ensure variations in mechanical strength and porosity. The specimens were subjected to accelerated carbonation in a chamber with 3% CO2, 65% RH and 23 °C for 14, 28 and 42 days, so that a database of 1536 carbonation measurements was produced. Internal and surface moisture of the concrete were measured at various stages throughout the experiment. Statistical analysis revealed that the preconditioning method significantly impacted the concrete’s carbonation rate - Fcalc (126.68) ≫ Ftab (2.61), with p-value ≅ 0. Preconditioning affected the concrete’s moisture content at the beginning of the process, and inverse linear relationships were found between concrete surface moisture and carbonation depth (0.85 ≤ R2 ≤ 0.99). The study points to the usefulness of the surface moisture technique to monitor specimens during carbonation tests, and it concluded that XP was the best among the four methods studied.

The quantification of southern corn leaf blight disease using deep UV fluorescence spectroscopy and autoencoder anomaly detection techniques.

Southern leaf blight (SLB) is a foliar disease caused by the fungus Cochliobolus heterostrophus infecting maize plants in humid, warm weather conditions. SLB causes production losses to corn producers in different regions of the world such as Latin America, Europe, India, and Africa. In this paper, we demonstrate a non-destructive method to quantify the signs of fungal infection in SLB-infected corn plants using a deep UV (DUV) fluorescence spectrometer, with a 248.6 nm excitation wavelength, to acquire the emission spectra of healthy and SLB-infected corn leaves. Fluorescence emission spectra of healthy and diseased leaves were used to train an Autoencoder (AE) anomaly detection algorithm-an unsupervised machine learning model-to quantify the phenotype associated with SLB-infected leaves. For all samples, the signature of corn leaves consisted of two prominent peaks around 450 nm and 325 nm. However, SLB-infected leaves showed a higher response at 325 nm compared to healthy leaves, which was correlated to the presence of C. heterostrophus based on disease severity ratings from Visual Scores (VS). Specifically, we observed a linear inverse relationship between the AE error and the VS (R2 = 0.94 and RMSE = 0.935). With improved hardware, this method may enable improved quantification of SLB infection versus visual scoring based on e.g., fungal spore concentration per unit area and spatial localization.

Heterogeneous body compositions and all-cause mortality in acute coronary syndrome patients: a ten-year retrospective cohort study.

The association of different body components, including lean mass and body fat, with the risk of death in acute coronary syndrome (ACS) patients are unclear. We enrolled adults diagnosed with ACS at our center between January 2011 and December 2012 and obtained follow-up outcomes via telephone questionnaires. We used restricted cubic splines (RCS) with the Cox proportional hazards model to analyze the associations between body mass index (BMI), predicted lean mass index (LMI), predicted body fat percentage (BF), and the value of LMI/BF with 10-year mortality. We also examined the secondary outcome of death during hospitalization. During the maximum 10-year follow-up of 1398 patients, 331 deaths (23.6%) occurred, and a U-shaped relationship was found between BMI and death risk (P nonlinearity = 0.03). After adjusting for age and history of diabetes, the overweight group (24 ≤ BMI < 28 kg/m2) had the lowest mortality (HR = 0.53, 95% CI: 0.29-0.99). Predicted LMI and LMI/BF had an inverse linear relationship with a 10-year death risk (P nonlinearity = 0.24 and P nonlinearity = 0.38, respectively), while an increase in BF was associated with increased mortality (P nonlinearity = 0.64). During hospitalization, 31 deaths (2.2%) were recorded, and the associations of the indicators with in-hospital mortality were consistent with the long-term outcome analyses. Our study provides new insight into the "obesity paradox" in ACS patients, highlighting the importance of considering body composition heterogeneity. Predicted LMI and BF may serve as useful tools for assessing nutritional status and predicting the prognosis of ACS, based on their linear associations with all-cause mortality.