Negative Linear Correlation Research Articles

Myocardial determinants of Functional limitation in advanced Fabry cardiomyopathy

Abstract Background Cardiac involvement in Fabry Disease (FD) manifests as left ventricular hypertrophy (LVH) often complicated by myocardial fibrosis and/or inflammation. Both LVH and advanced tissue alterations can be non-invasively detected and quantified by cardiac magnetic resonance (CMR) with Late Gadolinium Enhancement (LGE). Impairment in functional capacity has been previously reported in FD patients. However, there is limited data regarding the determinants of myocardial alterations in exercise intolerance in FD. Methods Among 190 consecutive FD patients referred for CMR, 41 simultaneously performed a cardiopulmonary exercise test (CPET) to evaluate functional capacity. All patients underwent an extensive CMR protocol to provide a detailed evaluation of cardiac morphology and function, including multiparametric tissue characterization. CPET parameters were compared between patients with advanced Fabry cardiomyopathy (Group B), characterized by hypertrophy, inflammation, and fibrosis, and FD patients without irreversible cardiac damage (Group A). Results Group B patients were older compared to Group A (57.0 years vs 33.5 years, p<0.001), had a greater LVH (LVMI: 117 g/sqm vs 76.5 g/sqm, p<0.001; LVMWT 17 vs 10 mm, p<0.001). LV ejection fraction was preserved in both groups but Group B patients had a lower peak VO2 value compared to group A (17.8 ml/kg/min vs 21.9 ml/kg/min, p=0.025), a lower (but not significant) percent-predicted peak VO2. A negative linear correlation was identified between the LGE extension (expressed as % of LV mass) and peak VO2 (r=-0.553, p=0.014). This correlation remained consistent even after excluding patients under chronic beta-blocker therapy (r=-0.678, p=0.045). No significant correlation between LV mass and peak VO2 was found. Conclusions in patients with FD, the presence of advanced tissue alterations detected by LGE is associated with reduced functional capacity (low peak VO2) despite preserved LV ejection fraction, with a significant negative correlation.

Lowering the risk of hyperuricemia and gout is associated with ideal cardiovascular health

BackgroundHyperuricemia (HUA) and gout have been demonstrated as independent risk factors for cardiovascular disease. The relationship between the recently updated Life’s Essentials 8 (LE8), which measures ideal cardiovascular health (CVH), and HUA and gout remains unclear. The aim of this study was to explore the relationship between CVH and the prevalence of HUA and gout among a nationally representative sample of US adults.MethodsThis study utilized cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) for the years 2007 to 2018. The CVH scores and their corresponding components were defined according to the guidelines established by the American Heart Association. The association between the LE8 score and both HUA and gout was assessed using weighted multivariable logistic and restricted cubic spline (RCS) models.ResultsAmong the 21,155 participants aged 20 years and older, the prevalence of HUA was 17.20% (95% CI, 16.05–18.36%), and the prevalence of gout was 3.58% (95% CI, 3.13–4.02%). After adjusting for potential confounders, compared to participants exhibiting low CVH, the multivariable adjusted odds ratio (OR) for HUA was 0.65 (95% CI, 0.56–0.75) in those with moderate CVH, and 0.25 (95% CI, 0.20–0.31) in those with high CVH. Additionally, compared to participants with low CVH, the multivariable adjusted OR for gout was 0.66 (95% CI, 0.53–0.81) in those with moderate CVH and 0.32 (95% CI, 0.20–0.50) in those with high CVH. The LE8 score exhibited a significant nonlinear negative association with HUA and linear negative correlation with gout. In subgroup analyses focusing on HUA, significant interactions were observed between LE8 score and age, sex, and CKD (P for interaction < 0.05). For gout, only a significant interaction between LE8 score and sex was observed (P for interaction < 0.05).ConclusionsAmong adults, there was a significant negative correlation between LE8 score and the prevalence of HUA and gout. Maintaining an ideal CVH may be beneficial in reducing the burden of HUA and gout.

Determining the Climate Type and Calculating the Drought Index during the Rainy Months for the Stations of Diwaniya, Samawa and Nasiriya in Southern Iraq

In this research, the climate type for the rainy months (January, February, March, April, May, October, November, December) was determined for three selected stations in southern Iraq (Diwaniyah, Samawah, Nasiriyah). By calculating the drought index for each of the rainy months mentioned above using Demarton's equation described in (Mohammed, 2020) Based on climate data including temperatures in Celsius and rainfall amounts for the above-mentioned stations for the period (2000-2021) which were obtained from the Iraqi General Commission for Meteorology and Seismic Monitoring. The results showed the mastery of arid and semi-arid climate in all study stations during most of the rainy months. Except for the months of December and January, where the climate is semi-humid in the stations of Nasiriyah and Diwaniyah, respectively. As for Samawah station, the climate is arid and semi-arid during all rainy months. The results of the statistical analysis using Excel program (2010) also showed a strong positive linear correlation between the values of the drought index and the amounts of rainfall during the rainy months at the stations (Diwaniya, Samawa, Nasiriya), where the values of the correlation coefficient reached (0.961, 0.953, 0.954) respectively. As for the linear correlation between the values of the drought index and the temperatures during the rainy months, the results showed a strong negative linear correlation between them, as the values of the correlation coefficient reached (-0.821, -0.836, -0.822) at the stations (Diwaniya, Samawa, Nasiriya) respectively.

Associations between nine dietary minerals intake and all-cause mortality in individuals with atherosclerotic cardiovascular disease.

Varied intake of dietary minerals critically affects cardiovascular health. This study examines the associations of nine dietary minerals intake with all-cause mortality in atherosclerotic cardiovascular diseases (ASCVDs). This study analyzed 4,125 individuals with ASCVD from the National Health and Nutrition Examination Survey, employing Kaplan-Meier survival analyses, weighted Cox models, and restricted cubic splines to assess linear and nonlinear relationships between dietary minerals intake and all-cause mortality. Associations across different body mass index (BMI) categories were also evaluated separately. Over 6.25 years of median follow-up, 1,582 deaths were documented. Adjusted for potential covariates, results show a negative linear correlation between dietary magnesium intake and all-cause mortality (p for trend <0.001). Compared to the lowest quartile, all-cause mortality risk in the highest quartile was found to be 0.63 (95% CI 0.49-0.81). The associations between intake of the other eight dietary minerals and all-cause mortality were not robust. BMI significantly influenced the links between dietary minerals intake and all-cause mortality (p for interaction <0.05). Across BMI categories, significant negative associations were found between intake of magnesium, phosphorus, potassium, sodium, and copper and all-cause mortality in underweight or normal weight groups. In overweight individuals, intake of calcium, iron, magnesium, and potassium was negatively linked to all-cause mortality. For obese groups, sodium intake negatively affected all-cause mortality (p for trend <0.001). Unlike other dietary minerals, increased magnesium intake significantly reduced all-cause mortality risk in ASCVD. BMI influenced the associations between dietary minerals intake and all-cause mortality.

Electrical monitoring of single-event protonation dynamics at the solid-liquid interface and its regulation by external mechanical forces

Detecting chemical reaction dynamics at solid-liquid interfaces is important for understanding heterogeneous reactions. However, there is a lack of exploration of interface reaction dynamics from the single-molecule perspective, which can reveal the intrinsic reaction mechanism underlying ensemble experiments. Here, single-event protonation reaction dynamics at a solid-liquid interface are studied in-situ using single-molecule junctions. Molecules with amino terminal groups are used to construct single-molecule junctions. An interfacial cationic state present after protonation is discovered. Real-time electrical measurements are used to monitor the reversible reaction between protonated and deprotonated states, thereby revealing the interfacial reaction mechanism through dynamic analysis. The protonation reaction rate constant has a linear positive correlation with proton concentration, whereas the deprotonation reaction rate constant has a linear negative correlation. In addition, external mechanical forces can effectively regulate the protonation reaction process. This work provides a single-molecule perspective for exploring interface science, which will contribute to the development of heterogeneous catalysis and electrochemistry.

Superhydrophobic foamed concrete based on response surface method: Mix design and its potential application in roofing systems

This study employs the response surface method to optimize the mixture design of superhydrophobic foamed concrete. The study investigates the influence of calcium stearate (CS, dosage 1 %∼5 %), polydimethylsiloxane (PDMS, dosage 2 %∼8 %), and hydroxypropyl methylcellulose (HPMC, dosage 0.05 %∼0.2 %) on various properties of foamed concrete, including density, compressive strength, contact angle, and water absorption. Additionally, the research explores the application of superhydrophobic foamed concrete in integrated roofing systems and assesses its thermal and structural performance through finite element analysis. Results reveal that foamed concrete achieves a contact angle greater than 150° when formulated with a mix ratio of CS (3 %), PDMS (8 %), and HPMC (0.05 %), or CS (3 %), PDMS (5 %), and HPMC (0.125 %). A negative linear correlation between the heat transfer coefficient and the thickness of foamed concrete is found. Furthermore, the heat transfer coefficient is inversely related to the spacing between the concave and convex drainage boards. Specifically, for a toe spacing of 50 mm and foamed concrete thickness exceeding 70 mm, the heat transfer coefficient of the roof measures 0.788 W/(m²·K). When the roof thickness increases from 70 mm to 100 mm, the roof heat transfer coefficient drops to 0.69 W/(m2∙K). When the toe spacing is increased from 50 mm to 60 mm, the heat transfer coefficient of the roof drops sharply to about 0.66 W/(m2∙K) at the thickness of 50 mm. The insulation requirements for the roof are satisfactorily met to 0.8 W/(m²·K). Under applied roof loads, the maximum von Mises stress experienced by the integrated roof is 0.6 MPa at a toe spacing of 50 mm. With the increase of the roof thickness, the maximum value of the DAMAGEC damage coefficient gradually decreases from 0.3 to 0.17. The maximum damage position has always been at the weak position of the four corners, which is consistent with the actual use status. The research findings on superhydrophobic foamed concrete have significant theoretical and engineering application value. Moreover, the construction of an "insulation/hydrophobic integrated" roof system demonstrates the feasibility of an integrated roof system and the potential for insulation/hydrophobic integration in roof system construction.

The possible connection between neutrophil-to-high-density lipoprotein ratio and cerebral perfusion in clinically established corticobasal syndrome: a pilot study.

Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) are tauopathic atypical parkinsonisms. Given their overlap in terms of clinical manifestation, there is growing interest in the mechanisms leading to these entities. In total, 71 patients were included in the study, 19 of whom were clinically diagnosed with CBS, 37 with PSP, and 15 with Parkinson's disease (PD). The mean ages of the participants were 72.8, 72.9, and 64.0 years, respectively, and the disease duration varied from 3 to 6 years. Each individual underwent blood collection. Morphological and biochemical evaluation of blood samples was performed to analyze the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-high-density lipoprotein ratio (NHR). A single-photon emission computed tomography (SPECT) with technetium-99m hexamethylpropyleneamine oxime (99Tc-HMPAO) tracer was used to assess perfusion in two regions of interest (ROI): the thalamus and insula. Using Pearson correlation to assess the linear relationship between NHR and perfusion in the insula and thalamus for CBS, PSP, and PD patients, the authors intended to verify possible correlations between NLR, PLR, and NHR and perfusion in the indicated ROIs. The study revealed a negative linear correlation between NHR and perfusion of both the left (Insula L; R = -0.59) and right (Insula R; R = -0.58) insula regions. Similar to the insula, a linear correlation between NHR and activity in both the left (Thalamus L) and right (Thalamus R) thalamus regions in CBS subjects with a relatively stronger correlation in the right thalamus (R = -0.64 vs. R = -0.58) was found. These observations were not confirmed in PSP and PD patients. Simultaneously using non-specific parameters for peripheral inflammation (NLR, PLR, and NHR) and perfusion, SPECT may be an interesting beginning point for further analysis of inflammatory disease mechanisms. To the best of our knowledge, this is the first study to address the potential correlation between the peripheral neuroinflammatory markers NLR, PLR, and NHR and perfusion disturbances in particular ROIs.

Role of dislocation behavior during aging in high-temperature microstructural evolution and creep property of single crystal superalloys

Single-crystal superalloys of turbine blades suffer unexpected performance deterioration, even when manufactured with optimal γ/γ′ phase morphology. This study successfully reproduced this abnormal decrease in high-temperature creep properties by applying optimal aging treatments to a skillfully designed model single-crystal superalloy. Microstructural evidence indicates that interfacial dislocations deposited during aging processes weaken dislocation distribution anisotropy (DDA) in the steady creep stage and place γ′-topological inversion ahead of the competition between γ′-rafting and it, leading to an increase in the minimum creep rate. Through constitutive equations and inductive research, a linear negative correlation between the minimum creep rate and DDA was established. A new concept of “phase-interface freshness” is proposed as a quantitative characterization of interfacial dislocation deposition after preparation to reflect the ability to stimulate the beneficial DDA. These results help us further understand thermal processes such as aging, coating, and welding, providing theoretical support for the design and optimization of thermal processes.

Synergic effects of physio‐mechanical performances on sliding‐rolling tribological and abrasion behaviors of polyisoprene based aviation tire treads

AbstractAbrasion and tribological properties of tread rubber play a crucial role in governing the service life of aviation tires and the safety of aircrafts. Polyisoprene (IR) with the same chemical structure as natural rubber shows great potential for application in aviation tires. Herein, the abrasion and tribological behaviors of IR based composites under sliding‐rolling conditions were investigated in relation to the carbon black (CB N234) content, sliding‐rolling ratio, ambient temperature, and counterparts in order to provide guidance for the development of high‐performance aviation tire treads. Moreover, the relationship between wear performances and physical–mechanical properties was discussed to establish a prediction model. The results revealed that physical and mechanical properties affected wear performances in a synergetic manner, which could be described as a negative linear correlation of the folding wear with the product of hardness and rebound resilience (H4R) and the ratio between rebound resilience and tensile strength ((1‐R)/σ) even at elevated temperature and sliding‐rolling ratio regardless of the counterpart. The increase in CB N234 content and sliding‐rolling (s‐r) ratio resulted in a transition of the wear mechanism from folding to abrasion due to the formation of soft rubber particles with a certain fluidity and a lubricating transfer film that was located at the friction interface and was generated by the thermal‐mechanical degradation of the IR matrix when it was rubbed against steel counterparts, which marred the aforementioned negative linear relationship.Highlights The increase in temperature improved the abrasion resistance of tire treads. The folding wear was negatively and linearly related to H4R and (1‐R)/σ. Increasing CB N234 content and s‐r ratio made a transition of wear mechanism.

Association between systemic inflammatory markers and all-cause mortality in patients with stroke: A prospective study using data from the UK Biobank

Background and aimsThe systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) are novel inflammatory biomarkers used to determine various disease prognoses. However, the effects of these systemic inflammatory markers on all-cause mortality in patients with stroke remain unclear. MethodsWe used data from the UK Biobank for this prospective analysis. Overall, 6,020 eligible individuals were included. Over a median follow-up of 13.4 years, 1,233 participants died. We examined the effects of systemic inflammatory markers on all-cause mortality using random survival forest (RSF) and Cox proportional hazards models. Covariate adjustments in the Cox model, selected by RSF, included age, sex, body mass index (BMI), Townsend deprivation index, smoking status, alcohol intake frequency, sleep duration, diabetes, and malignant neoplasms. ResultsIn the marginal effect plots and restricted cubic spline analysis for systemic inflammatory markers, LMR exhibited a linear negative correlation, NLR showed a linear positive correlation, and SII and PLR demonstrated a U-shaped association. After covariates were adjusted, the all-cause mortality risk increased by 14 % for LMR <4 (hazards ratio [HR]: 1.14, 95 % confidence interval [CI]: 1.01–1.29; p= 0.03), by 26 % for NLR ≥2 (HR: 1.26; 95 % CI: 1.11–1.43; p < 0.001),by 26 % for PLR ≥175 (HR: 1.26; 95 % CI: 1.07–1.47; p < 0.001), and by 31 % for SII ≥526 (HR: 1.31; 95 % CI, 1.16–1.47; p= 0.014). In addition, sensitivity analyses, excluding participants who had been followed-up for <2 years and those with malignant neoplasms, yielded results consistent with those of previous research. ConclusionSII, NLR, PLR, and LMR significantly correlate with all-cause mortality in stroke patients. Thresholds established by the RSF model could potentially refine prognostic decision-making in stroke care.

Association between dietary β-carotene intake with Parkinson's disease and all-cause mortality among American adults aged 40 and older (NHANES 2001-2018).

The existing evidence concerning the correlation between dietary β-carotene intake and Parkinson's disease (PD) is currently deemed insufficient. Thus, this research aims to investigate the relationship between dietary β-carotene intake and both the prevalence of PD and all-cause mortality within the US (United States) population. The research employed cross-sectional analysis and cohort studies utilizing data from 16,852 participants in the National Health and Nutrition Examination Survey (NHANES) spanning from 2001 to 2018. Weighted logistic regression, weighted cox regression, restricted cubic splines (RCS), subgroup analysis, and sensitivity analyses were employed to validate the research objectives. Among all eligible subjects, the mean age was 59.62 ± 11.77 years, with a prevalence of PD at 1.82% overall, with 43.88% in males. In the fully adjusted model, dietary β-carotene intake exhibited a negative association with PD prevalence [odds ratio (OR) = 0.95; 95% confidence interval (CI): 0.90 ~ 0.997; p = 0.040]. Utilizing RCS analysis, a negative linear correlation between dietary β-carotene intake and PD prevalence was observed (non-linear p = 0.857). Furthermore, after controlling for multiple variables, dietary β-carotene intake was inversely associated with all-cause mortality [Hazard ratios (HR) = 0.98; 95% CI: 0.97 ~ 0.99; p = 0.002], with RCS curves indicating a negative linear relationship (nonlinear: p = 0.082). Comparable patterns of association were noted in subgroup analyses, and consistent findings were derived from additional sensitivity analyses. The cross-sectional and cohort study reveals a significant negative correlation between dietary β-carotene intake and both the prevalence of PD and all-cause mortality in the general population. This suggested that supplementing with dietary β-carotene might have certain benefits for reducing the prevalence of PD and all-cause mortality. However, further rigorously designed expected studies are needed to establish the causal relationship between them.

Exposure of cumulative atherogenic index of plasma and the development of prediabetes in middle-aged and elderly individuals: evidence from the CHARLS cohort study

BackgroundThe impact of dynamic changes in the degree of atherosclerosis on the development of prediabetes remains unclear. This study aims to investigate the association between cumulative atherogenic index of plasma (CumAIP) exposure during follow-up and the development of prediabetes in middle-aged and elderly individuals.MethodsA total of 2,939 prediabetic participants from the first wave of the China Health and Retirement Longitudinal Study (CHARLS) were included. The outcomes for these patients, including progression to diabetes and regression to normal fasting glucose (NFG), were determined using data from the third wave. CumAIP was calculated as the ratio of the average AIP values measured during the first and third waves to the total exposure duration. The association between CumAIP and the development of prediabetes was analyzed using multivariable Cox regression and restricted cubic spline (RCS) regression.ResultsDuring a median follow-up period of 3 years, 15.21% of prediabetic patients progressed to diabetes, and 22.12% regressed to NFG. Among the groups categorized by CumAIP quartiles, the proportion of prediabetes progressing to diabetes gradually increased (Q1: 10.61%, Q2: 13.62%, Q3: 15.65%, Q4: 20.95%), while the proportion regressing to NFG gradually decreased (Q1: 23.54%, Q2: 23.71%, Q3: 22.18%, Q4: 19.05%). Multivariable-adjusted Cox regression showed a significant positive linear correlation between high CumAIP exposure and prediabetes progression, and a significant negative linear correlation with prediabetes regression. Furthermore, in a stratified analysis, it was found that compared to married individuals, those who were unmarried (including separated, divorced, widowed, or never married) had a relatively higher risk of CumAIP-related diabetes.ConclusionCumAIP is closely associated with the development of prediabetes. High CumAIP exposure not only increases the risk of prediabetes progression but also hinders its regression within a certain range. These findings suggest that monitoring and maintaining appropriate AIP levels may help prevent the deterioration of blood glucose levels.

The correlation of the modulation complexity score (MCS) with the number of segments and local gamma passing rate for the Intensity Modulated Radiation Therapy (IMRT) treatment planning delivery.

To compare the modulation complexity scores across treatment sites, and to examine their connection with monitor unit, segment number and global and local gamma passing percentage. The cross-sectional study was conducted at the Baghdad Centre for Radiation Therapy and Nuclear Medicine, Baghdad Medical City, Baghdad, Iraq, from May 2021 to February 2022. Included were 34 patients, with the age range between 20 - 50 years, subjected to intensity-modulated radiation therapy for head and neck tumours in group A or pelvic tumours in group B. Treatment planning was done using Monaco 5.1, and radiotherapy was done using Synergy linear accelerator. Modulation complexity scores were calculated using MATLAB 2019a. Data was analysed using SPSS 24. Of the 34 patients, 22(64.7%) were in group A; 12(54.5%) males and 10(45.5%) females. There were 12(35.3%) patients in group B; 8(66.7%) females and 4(33.3%) males. The number of segments was greater in group B than group A. A modest positive linear association was seen in group A, demonstrating that an increase in segment numbers resulted in a rise in modulation complexity score (R2=0.0244). Group B tumours had inverse negative linear correlation (R2=0.0189). As the complexity of plans increased in group A, local gamma passing percentage decreased (R2=0.0452). Group B showed a slight negative connection with modulation complexity score (R2=0.0622). The modulation complexity score may be used to provide a simple prediction for pre-treatment verification, and it may also serve as a simple quality assurance tool for intensity-modulated radiation therapy plans.

Association between baseline serum bicarbonate and the risk of postoperative delirium in patients undergoing cardiac surgery in the ICU: a retrospective study from the MIMIC-IV database

BackgroundAlthough serum bicarbonate is a reliable predictor of various disease complications, its relationship with postoperative delirium (POD) remains unclear. Our research aimed to assess the effect of baseline serum bicarbonate levels on the incidence of POD in cardiac surgery patients.MethodsA retrospective analysis was conducted on cardiac surgery patients who met specific inclusion and exclusion criteria, using data from the Marketplace for Information in Critical Care Medicine (MIMIC-IV) database. Univariate and multivariate logistic regression models are employed to explore the correlation between serum bicarbonate levels and the risk of POD, and their predictive efficacy is assessed by means of restricted cubic spline regression models (RCS) and receiver operating characteristic curves (ROC). In addition, subgroup and sensitivity analyses are conducted to test the robustness of the results.ResultsIn this study, 5,422 patients were included, where the incidence of POD was 13.0%. For each 1 mmol/L increase in bicarbonate, a 13% reduction in the risk of POD was observed in the fully adjusted model (OR = 0.87, 95% CI: 0.83–0.91, P < 0.001). The RCS model demonstrated a linear negative correlation between the level of bicarbonate and the risk of POD (P for nonlinearity = 0.987). The ROC curve analysis demonstrated that the bicarbonate level had moderate predictive efficacy (AUC = 0.629). Both subgroup and sensitivity analyses reaffirmed the robustness of these results.ConclusionsLower baseline serum bicarbonate levels in cardiac surgery patients are linked to a higher risk of POD. Monitoring and adjusting serum bicarbonate levels may help identify high-risk patients and potentially improve outcomes.

Particle Dynamics Study on Influencing Factors of Ice Slurry Flow Characteristics in District Cooling Systems

In district cooling systems, substituting the conventional cooling medium with ice slurry represents an ideal approach to achieve economical operation. During pipeline transportation, ice slurry exhibits heterogeneous flow characteristics distinct from those of pure fluids. Consequently, investigating the flow field characteristics of non-homogeneous ice slurry, quantitatively analyzing the rheological variations and flow resistance laws due to the uneven distribution of ice particles, and standardizing the comprehension and depiction of flow patterns within ice slurry pipes hold significant theoretical importance and practical value. This study analyzes the heterogeneous isothermal flow characteristics of ice slurry in a straight pipe by employing particle dynamics and the Euler–Euler dual-fluid model. Taking into account the impact of ice particles’ non-uniform distribution on the rheological properties of ice slurry, a particle concentration diffusion equation is incorporated to develop an isothermal flow resistance model for ice slurry. The flow behavior of ice slurry with initial average ice particle fractions (IPFs) ranging from 0% to 20% in DN20 horizontal straight and elbow pipes is examined. The findings reveal that the degree of heterogeneous flow in ice slurry is inversely proportional to the initial velocity and directly proportional to the initial concentration of ice particles. When the flow velocity is close to 0.5 m/s, the flow resistance of ice particles exhibits a linear positive correlation with changes in flow velocity, whereas the flow resistance of the fluid-carrying phase displays a linear negative correlation. As the flow rate increases to 1 m/s, the contribution of each phase to the total flow resistance becomes independent of the initial velocity parameter. Additionally, the drag fraction of the ice particle phase is positively associated with the initial concentration of ice particles. Furthermore, the phenomenon of “secondary flow” arises when ice slurry flows through an elbow, enhancing the mixing of ice particles with the carrier fluid. The extent of this mixing intensifies with a decrease in the turning radius and an increase in the initial velocity.

Relationship between surfactant content and the properties of microfibrillated cellulose/high density polyethylene composites

AbstractMicrofibrillated cellulose (MFC) was uniformly dispersed in high‐density polyethylene (HDPE) using a large amount of surfactant, and composites were prepared after removing the surfactant at different contents. The structural, morphological, thermal, and tensile properties of these composites were systematically investigated. The results demonstrated an asymptotic relationship between the amount of surfactant removed and the number of removal cycles. A negative linear correlation was observed between the surfactant content and the tensile strength, tensile modulus, and storage modulus at −20 °C of the composites, while a positive linear correlation was found with the loss modulus at −20 °C. Excessive surfactant adversely affected the dispersion of MFC, as well as the mechanical properties and thermal stability of the composites. However, when the surfactant content was below 2.8%, its impact on the composite properties was minimal, and the tensile strength, modulus, and thermal stability of the composites were significantly improved compared to neat HDPE. These findings indicate that surfactant pretreatment is an effective strategy for dispersing MFC in non‐polar polymers, and controlling the surfactant content in the final product can effectively tailor the properties of the resulting composites.Highlights Confirms the relationship between surfactant content and MFC/HDPE composite properties. Surfactant content showed an asymptotic relationship with removal cycles. Surfactant content and mechanical properties exhibited a negative linear correlation. Surfactant content and thermal stability exhibited a negative relationship. Surfactant content had minor impact when below 2.8%.

Associations between hypertensive snowbirds' length of migratory stay and blood pressure control

Objective: To explore the relationship between the hypertensive snowbirds' length of migratory stay and their blood pressure control and blood pressure levels. Methods: This study was a cross-sectional study. A population of snowbirds with hypertension was recruited between October and November 2022, and a structured questionnaire was used to collect their self-measured blood pressure and length of stay in Hainan Province. The blood pressure control status is determined based on self-measured blood pressure. According to the self-measured blood pressure to determine whether the blood pressure was well controlled. The associations between snowbirds' length of stay and their blood pressure control as well as their self-measured blood pressure were analyzed using restricted cubic splines. Results: A total of 362 research subjects were included, 169(46.7%) of whom were male, and their age was (69.7±7.0) years old. The participants' self-measured systolic blood pressure and diastolic blood pressure were (129.1±16.2) mmHg (1 mmHg=0.133 kPa) and (78.9±10.1) mmHg, respectively. Overall, 174 (48.1%) participants attained adequate blood pressure control. The median length of stay in Wuzhishan City was 7(6, 7) months. There was an inverted U-shaped association between snowbirds' length of stay and blood pressure control (overall: P=0.023; nonlinearity: P=0.014), where participants with a length of stay of 7 months had the highest rate of blood pressure control. There is a U-shaped curve relationship between length of stay and systolic blood pressure (overall: P=0.001; nonlinearity: P=0.033), and a linear negative correlation with diastolic blood pressure (β=-1.19, P=0.003). Conclusions: Compared with hypertensive snowbirds with too long or too short lengths of stay, snowbirds who stayed in Wuzhishan City for seven months have better blood pressure control, and systolic blood pressure is also lower.

Comprehensive analysis of the relationship between yield stress and dewatering performance in sludge conditioning: Insights from various treatment methods

Understanding the relationship between sludge yield stress (σy) and dewatering performance is essential for optimizing sludge conditioning processes. This study systematically investigates the effects of various conditioning methods—including thermal hydrolysis (TH), freezing/thawing (FT), anaerobic digestion (AD), polyaluminum chloride (PAC), polyacrylamide (PAM), and Fenton treatment (Fenton)—on sludge yield stress and its correlation with dewatering efficiency. Using linear regression, partial least squares regression (PLSR), and correlation heatmap analyses, we reveal significant variations in the correlation between σy and dewatering indexes, including moisture content (Mc), capillary suction time (CST), and bound water proportion (Wb/Wt), depending on the conditioning method and intensity. Under FT and PAM conditioning, σy shows a strong negative linear correlation with dewatering performance, with Pearson's r values exceeding −0.880, indicating that a decrease in σy corresponds to improved dewatering efficiency. Conversely, AD conditioning exhibits a positive linear correlation, with r values up to 0.993, suggesting that an increase in σy correlates with reduced dewatering efficiency. For TH, PAC, and Fenton treatments, the correlation between σy and dewatering metrics is highly sensitive to changes in treatment intensity. In the PLSR analysis, the VIP values, which quantify the importance of each predictor variable, indicate that Wb/Wt in TH conditioning (VIP = 1.649) and CST in PAC (VIP = 1.309) and Fenton (VIP = 1.299) conditioning strongly influence σy. This study highlights the significant impact of conditioning methods and intensities on the correlation between σy and dewatering performance. While σy provides valuable insights as a predictive indicator, its predictive power is limited in more complex conditioning scenarios. Therefore, optimizing conditioning intensity and incorporating multiple rheological parameters are essential for achieving superior sludge dewatering outcomes.

Investigation of airflow thermal ice melting process under various flight conditions

The challenge of preventing and removing ice from exposed regions of aircraft is a significant engineering concern. Understanding the melting process of ice due to aerodynamic heating during flight is essential for developing UAV flight strategies in icy conditions. This paper analyzes the heat transfer mechanisms involved in airflow over ice and introduces a theoretical model to estimate the ice melting rate, using principles of turbulent heat transfer at the stagnation point. The study also discusses the impact of environmental conditions on ice melting rates. Findings indicate that the melting speed of the ice surface exhibits a negative linear correlation with the initial temperature of the ice, whereas it shows a nonlinear correlation with airflow velocity and total temperature of the incoming flow. Lower airflow velocity or total temperature of the incoming flow enhances the sensitivity of ice melting speed to changes. Additionally, lower ice density results in a higher melting speed, showing an exponential relationship with factors like average droplet diameter, airflow velocity, and airfoil leading edge diameter in the cloud field during icing. Experiments conducted using a small jet test bench and an icing wind tunnel confirmed the impact of varying conditions on ice melting rates. The deviation between experimental results and theoretical predictions was under 5 %. These conclusions offer valuable insights for flight safety planning of unprotected iced aircraft in challenging environments.

Seasonal variation in vegetation cooling effect and its driving factors in a subtropical megacity

The urban heat island (UHI) effect has become a global issue, attracting widespread attention in recent years. Urban vegetation is an effective way to mitigate UHI through evapotranspiration (ET). However, the seasonal variation in vegetation cooling effect and its driving factors have not been well investigated. Therefore, the seasonal UHI intensity (UHII) on typical clear days in 2021 was calculated for Shenzhen based on the land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS). The slope between UHII and vegetation coverage was then used to characterize the vegetation cooling effect. Results showed that: (1) there is a significant negative linear correlation between UHII and vegetation coverage, with slopes mostly less than −1 and coefficients of determination (R2) larger than 0.4. (2) The slopes varied seasonally, indicating a larger vegetation cooling effect during summer daytime. A 10 % increase in vegetation coverage can reduce the daytime UHII by 0.16 °C in January and 0.59 °C in June, while at nighttime, the cooling effect varied between 0.12 °C in January and 0.27 °C in June. The daytime and nighttime UHII for the whole year can be reduced by 0.43 °C and 0.24 °C, respectively. (3) The seasonal variation in vegetation cooling effects during the daytime can be largely explained by that of ET, which is mainly driven by leaf area index (LAI).