Concentration Of Small Particles Research Articles

Associations Between High-Density Lipoprotein Cholesterol Efflux and Brain Grey Matter Volume.

Objective: High-density lipoprotein cholesterol efflux function may prevent brain amyloid beta deposition and neurodegeneration. However, the relevance of this finding has not been established in the diverse middle-aged population. Methods: We examined 1826 adults (47% Black adults) who participated in the Dallas Heart Study to determine associations between high-density lipoprotein (HDL) measures and brain structure and function. White matter hyperintensities (WMH) and whole-brain grey matter volume (GMV) were measured using brain MRI, and the Montreal Cognitive Assessment (MoCA) was used to measure neurocognitive function. HDL cholesterol efflux capacity (HDL-CEC) was assessed using fluorescence-labeled cholesterol efflux from J774 macrophages, and HDL particle size measures were assessed using nuclear magnetic resonance (NMR) spectroscopy (LipoScience). Multivariable linear regressions were performed to elucidate associations between HDL-CEC and brain and cognitive phenotypes after adjustment for traditional risk factors such as age, smoking status, time spent in daily physical activity, and education level. Results: Higher HDL-CEC and small HDL particle (HDL-P) concentration were positively associated with higher GMV normalized to total cranial volume (TCV) (GMV/TCV) after adjustment for relevant risk factors (β = 0.078 [95% CI: 0.029, 0.126], p = 0.002, and β = 0.063 [95% CI: 0.014, 0.111], p = 0.012, respectively). Conversely, there were no associations between HDL measures and WMH or MoCA (all p > 0.05). Associations of HDL-CEC and small HDL-P with GMV/TCV were not modified by ApoE-ε4 status or race/ethnicity. Interpretation: Higher HDL cholesterol efflux and higher plasma concentration of small HDL-P were associated with higher GMV/TCV. Additional studies are needed to explore the potential neuroprotective functions of HDL.

5123 Remission of Antibodies Blocking the Insulin Receptor Reduces Atherogenicity of LDL Particles but Increases HDL Particle Atherogenicity

Abstract Disclosure: M. Hwang: None. R. Shamburek: None. M. Lightbourne: None. M. Sampson: None. A. Remaley: None. B. Abel: None. R.J. Brown: None. Background: Type B insulin resistance syndrome (TBIR) is a rare autoimmune disorder defined by the presence of autoantibodies against the insulin receptor, usually in the context of systemic autoimmune diseases such as lupus. In TBIR, insulin signaling is disrupted at the receptor-level, resulting in failure of insulin to both suppress hepatic glucose production and to stimulate de novo lipogenesis. This leads to a phenotype of extreme insulin resistance (IR) and hyperglycemia without dyslipidemia. IR and hyperglycemia resolve when remission of the autoantibody is induced by immunosuppression. Given the known association between IR and cardiovascular disease (CVD), we sought to compare biomarkers of CVD risk using lipoprotein particles measured by Nuclear Magnetic Resonance (NMR) in patients with TBIR during their active disease state vs remission. Methods: Patients with TBIR (N=14) had fasting labs including NMR lipoprotein profiles (analyzed using LP4 deconvolution algorithm) during active disease (positive antibodies to the insulin receptor and severe IR) and remission (defined by discontinuation of insulin or amelioration of hyperglycemia). Particle size (nm) and concentration of subclasses by size were measured for low-density lipoprotein (LDL) particles (nmol/L) and high-density lipoprotein (HDL) particles (umol/L). Results: Upon remission from TBIR, there were large decreases in hemoglobin A1c (from 10.9±3.0% to 6.1±1.1%, p<0.001) and insulin (from 1000.0 (715.9, 1000.0) mcU/mL to 16.8 (8.1, 39.2) mcU/mL, normal 2.6-24.9 mcU/mL, p<0.001), and increases in BMI (from 21.8±3.5 to 28.6±7.4 kg/m2, p<0.01), C3 (from 76±27 to 114±20 mg/dL, normal 82-185 mg/dL, p<0.01), and C4 (from 16±8 to 25±9 mg/dL, normal 15-53 mg/dL, p<0.01). After remission of TBIR, LDL profiles became less atherogenic: small LDL particle concentration decreased (from 523.4±170.2 to 362.8±119.7, normal 63.8-1719.6, p<0.01) and LDL particle size increased (from 20.6±0.5 to 21.2±0.3, normal 19.9 -21.6, p<0.01). By contrast, HDL profiles became more atherogenic after remission of TBIR: small HDL particle concentration increased (from 4.6±2.6 to 8.2±4.3, normal 6.6-19.3, p<0.01); the largest HDL particle concentration decreased (from 1.5±0.8 to 0.7±0.7, normal 0-1.2, p<0.01), and HDL particle size decreased (from 10.3±0.4 to 9.6±0.5, normal 8.4-9.9, p<0.001). Conclusions: Active TBIR is a pro-inflammatory state characterized by excess consumption of C3 and C4. Inflammation may contribute to an unfavorable LDL particle profile that improves after remission. However, lack of insulin signaling through the insulin receptor during active TBIR likely leads to an anti-atherogenic HDL profile that returns to normal levels when insulin signaling is restored after remission. Future studies will further investigate the role of insulin resistance and inflammation in CVD risk. Presentation: 6/3/2024

Third harmonic of the dynamic magnetic susceptibility of a concentrated ferrofluid: Numerical calculation and simple approximation formula.

Information about the nonlinear magnetic response of dispersions of magnetic particles is the basis for biomedical applications. In this paper, using analytical and numerical methods, the third harmonic of the dynamic susceptibility of an ensemble of moving magnetic particles in an ac magnetic field with an arbitrary amplitude is studied, taking into account interparticle interactions. A simple approximation formula is proposed to predict the third harmonic as a function of two parameters: the Langevin susceptibility χ_{L}, which is used to estimate the particle dipole-dipole interactions, and the Langevin parameter ξ, which represents the ratio of the energy of the magnetic moment interacting with the magnetic field to the thermal energy. The derived approximation formula corresponds with the known single-particle theories in the limit case of a small particle's concentration and is valid for concentrated dispersions of magnetic particles (with the Langevin susceptibility up to χ_{L}≤3) in high-amplitude ac fields (with the Langevin parameter up to ξ≤10).

Anaerobic dynamic membrane bioreactor treating sulfamethoxazole wastewater: advantages of dynamic membrane and its fouling mechanism

Discharge of improperly treated sulfamethoxazole (SMX) wastewater seriously threats environmental security and public health. Anaerobic dynamic membrane bioreactors (AnDMBRs) technology would be cost-effective for SMX wastewater treatment, considering its low cost and satisfactory treatment efficiency. The performance of AnDMBR, though demonstrated to be excellent in treating many types of wastewaters, was for the first time investigated for treating SMX wastewater. Particular efforts were devoted to elucidating the advantages of dynamic membrane (DM) and the governing mechanism responsible for DM fouling with the presence of SMX. The threshold SMX concentration for AnDMBR was found to be 90 mg/L and the AnDMBR exhibited excellent removal efficiency of COD (90.91 %) and SMX (88.95 %) as well as satisfactory acute toxicity reduction rate (88.84 %). It was noteworthy that the DM made indispensable contributions to the removal of COD (14.26 %) and SMX (22.20 %) as well as the acute reduction of toxicity (25.81 %). The presence of SMX significantly accelerated DM fouling mainly by increasing its specific resistance, which was attributed to the increased content of small particles, high-valence metal ions and EPS content (mainly hydrophobic proteins), resulting in a denser DM structure with lower porosity. Besides, the biofouling-related bacteria (Firmicutes) was found to be enriched in the DM with the presence of SMX.

Performances of two-stage electrostatic precipitator with different types of discharge electrodes of unipolar electrostatic agglomerator

Current-voltage characteristics of electrostatic agglomerator with three types of discharge electrodes, operating as the first stage of a two-stage electrostatic precipitator, and the effects of its operating parameter on the removal efficiency of this system for PM10 particles have been investigated. The results shown that the removal efficiency of the system of this specific design only weakly depends on the supply voltage of the AC kinematic electrostatic agglomerator in the supply voltage range of 18–26 kV. A synergistic effect between the operation of electrostatic agglomerator and electrostatic precipitator was obtained. By this effect, the removal efficiency of the whole system, i.e., the electrostatic agglomerator and electrostatic precipitator operating simultaneously, is higher than that determined as the combination of the removal efficiencies obtained for both of these stages operating alone. The effect of synergy results from the agglomeration of fly ash particles in the electrostatic agglomerator stage that decreases the concentration of small particles and increases their removal efficiency by electrostatic precipitator.

Dyslipidemias in multiple sclerosis

PurposeTo investigate the frequency of dyslipidemia phenotypes in multiple sclerosis and to assess the associations with lipoprotein particle size distributions. MethodsThis cross-sectional study included 203 healthy controls (HC), 221 relapsing-remitting MS (RRMS), and 126 progressive MS (PMS). A lipid profile with total cholesterol, high-density lipoprotein cholesterol (HDL-C), triglycerides, and apolipoprotein B levels were measured. Low density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol, large buoyant LDL-C and small dense LDL-C were calculated using the Sampson-NIH equations method. Dyslipidemia phenotypes were categorized by their nonHDL-C and triglyceride values. The diameters and concentrations of triglyceride-rich lipoprotein particles (TRLP), LDL particles (LDLP), and HDL particles (HDLP) were measured with proton NMR lipoprotein profiling. Serum proprotein convertase subtilisin/kexin type 9 (PCSK9) levels were obtained using immunoassay. ResultsThe frequencies of normolipidemia, and various dyslipidemia phenotypes were similar in HC, RRMS, and PMS. The size of the TRLP, very large TRLP, large TRLP, and small LDLP concentrations had a decreasing pattern of HC>RR>PMS. The lowest tertile of EDSS was associated with higher concentrations of HDLP and small HDLP in PMS. PCSK9 was associated with concentration of HDL particles, primarily via its effects on the concentration of small HDL particles. ConclusionsThere were no differences in the frequency of dyslipidemias in MS compared to healthy controls. Higher HDLP concentrations are associated with lower disability in PMS.

Pathways of ice multiplication in nimbostratus clouds during the Indian summer monsoon

The present study illustrates the microphysical parameters of nimbostratus clouds during the Indian summer monsoon using airborne and radar observations conducted as part of the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX), and simulations with the Weather Research and Forecasting (WRF) model. The study also analyzes the impact of secondary ice production (emphasizing the microphysical pathways of Hallett-Mossop (HM) as represented in the models) on cloud processes using model sensitivity simulations. The effect of possible pathways of riming during the HM process is the focus of the sensitivity simulations. Aircraft observations showed higher ice particle concentrations in the Hallett–Mossop zone (−3 °C to - 8 °C) along with the existence of smaller and larger cloud droplets, rimed needles, columns, and snow particles. Observations strongly suggested the active presence of the HM process in this cloud. The observed mean values of microphysical parameters including liquid water content, ice number concentrations, and maximum vertical velocity, agreed well with model simulations. The number concentration and water content of ice crystals and snow decreased in the HM zone during the HM inactive case. A reduction in rainfall is also observed in the absence of HM. HM increases convection as it causes a sudden increase in the number concentration of small ice particles, which causes rainwater to freeze quickly and water vapour to be consumed by diffusional growth. Latent heating is produced by both effects, which energizes the convection.

Social inequalities in pregnancy metabolic profile: findings from the multi-ethnic Born in Bradford cohort study.

Lower socioeconomic position (SEP) associates with adverse pregnancy and perinatal outcomes and with less favourable metabolic profile in nonpregnant adults. Socioeconomic differences in pregnancy metabolic profile are unknown. We investigated association between a composite measure of SEP and pregnancy metabolic profile in White European (WE) and South Asian (SA) women. We included 3,905 WE and 4,404 SA pregnant women from a population-based UK cohort. Latent class analysis was applied to nineteen individual, household, and area-based SEP indicators (collected by questionnaires or linkage to residential address) to derive a composite SEP latent variable. Targeted nuclear magnetic resonance spectroscopy was used to determine 148 metabolic traits from mid-pregnancy serum samples. Associations between SEP and metabolic traits were examined using linear regressions adjusted for gestational age and weighted by latent class probabilities. Five SEP sub-groups were identified and labelled 'Highest SEP' (48% WE and 52% SA), 'High-Medium SEP' (77% and 23%), 'Medium SEP' (56% and 44%) 'Low-Medium SEP' (21% and 79%), and 'Lowest SEP' (52% and 48%). Lower SEP was associated with more adverse levels of 113 metabolic traits, including lower high-density lipoprotein (HDL) and higher triglycerides and very low-density lipoprotein (VLDL) traits. For example, mean standardized difference (95%CI) in concentration of small VLDL particles (vs. Highest SEP) was 0.12 standard deviation (SD) units (0.05 to 0.20) for 'Medium SEP' and 0.25SD (0.18 to 0.32) for 'Lowest SEP'. There was statistical evidence of ethnic differences in associations of SEP with 31 traits, primarily characterised by stronger associations in WE women e.g., mean difference in HDL cholesterol in WE and SA women respectively (vs. Highest-SEP) was -0.30SD (-0.41 to -0.20) and -0.16SD (-0.27 to -0.05) for 'Medium SEP', and -0.62SD (-0.72 to -0.52) and -0.29SD (-0.40 to -0.20) for 'Lowest SEP'. We found widespread socioeconomic differences in metabolic traits in pregnant WE and SA women residing in the UK. Further research is needed to understand whether the socioeconomic differences we observe here reflect pre-conception differences or differences in the metabolic pregnancy response. If replicated, it would be important to explore if these differences contribute to socioeconomic differences in pregnancy outcomes.

Effect of different buried depth on the disintegration characteristic of red-bed soft rock and the evolution model of disintegration breakage under cyclic drying-wetting

The disintegration of red-bed soft rock exhibits a strong correlation with various geological disasters. However, the investigation into the evolutionary mechanisms underlying disintegration breakage has not yet received extensive exploration. In order to comprehensively examine the disintegration characteristics of red-bed soft rock, the slake durability tests were conducted to red-bed soft rocks of varying burial depths. Subsequently, an investigation was carried out to examine the disintegration characteristics and the evolution of disintegration parameters, including the coefficient of uniformity (Cu), coefficient of curvature (Cc), disintegration rate (DRE), disintegration ratio (Dr), and fractal dimension (D), throughout the disintegration process. Finally, employing the energy dissipation theory, an energy dissipation model was developed to predicate the disintegration process of samples at various burial depths. The findings demonstrate a decrease in the abundance of large particles and a concurrent increase in the abundance of small particles as the number of drying-wetting cycles increases. Furthermore, as the number of drying-wetting cycles increases, a significant alteration is observed in the content of particles larger than 10 mm, whereas the content of particles smaller than 10 mm undergoes only minor changes. The disintegration parameters, including the curvature coefficient, non-uniformity coefficient, disintegration rate, and fractal dimension, exhibit a positive correlation with the number of drying-wetting cycles. Conversely, the disintegration index demonstrates a decreasing trend with the increasing number of cycles. Nevertheless, as the burial depth increases, a notable trend emerges in the disintegration process, characterized by a gradual increase in the content of large particles alongside a progressive decrease in the content of small particles. Concurrently, the curvature coefficient, non-uniformity coefficient, disintegration rate, and fractal dimension exhibit a gradual decline, while the durability index experiences a gradual increase. In addition, based on the principle of energy dissipation, it is revealed that the surface energy increment of red-bed soft rock increases with the increase of the number of drying-wetting cycles, but decreases with the increase of burial depth. Ultimately, by leveraging the outcomes of energy dissipation analyses, a theoretical model is constructed to elucidate the correlation between surface energy and both the number of drying-wetting cycles and burial depth. This model serves as a theoretical reference for predicting the disintegration behavior of samples, offering valuable insights for future research endeavors.

Discrete element simulation of vibration compaction of slag subgrade

In this study, to improve the compaction quality and parameters of slag, discrete element models of irregular rock particles (10–60 mm) and circular soil particles (5 mm) were established based on on-site slag screening results. The motion of the vibratory roller was captured by coupling the roadbed model with the roller model in a simulation in which the roller vibrated and compacted the slag subgrade. The results indicated that (1) the best compaction was achieved when the small particle content was 40%, the medium particle content was 20%, and the large particle content was 40%. (2) When the slag was dominated by small rock particles, the optimum compaction frequency was 28 Hz, and when large rock particles dominated, the optimum compaction frequency was 33 Hz. (3) Rock particles were the primary particles that experienced stress in the vibration compaction, and the compressive force and displacement depended on the particle size. (4) The longitudinal and vertical displacements and rotation angles of the soil and rock particles were examined. The results of this study are conducive for advancing the understanding of slag compaction and improving the working efficiency and compaction quality of rollers.

Electrostatic particle ionization for suppressing air pollutants in cage-free layer facilities

The increasing demand for cage-free (CF) poultry farming raises concern regarding air pollutant emissions in these housing systems. Previous studies have indicated that air pollutants such as particulate matter (PM) and ammonia (NH3) pose substantial risks to the health of birds and workers. This study aimed to evaluate the efficacy of electrostatic particle ionization (EPI) technology with different lengths of ion precipitators in reducing air pollutants and investigate the relationship between PM reduction and electricity consumption. Four identical CF rooms were utilized, each accommodating 175 hens of 77 wk of age (WOA). A Latin Square Design method was employed, with 4 treatment lengths: T1 = control (0 m), T2 = 12 ft (3.7 m), T3 = 24 ft (7.3 m), and T4 = 36 ft (11.0 m), where room and WOA are considered as blocking factors. Daily PM concentrations, temperature, and humidity measurements were conducted over 24 h, while NH3 levels, litter moisture content (LMC), and ventilation were measured twice a week in each treatment room. Statistical analysis involved ANOVA, and mean comparisons were performed using the Tukey HSD method with a significance level of P ≤ 0.05. This study found that the EPI system with longer wires reduced PM2.5 concentrations (P ≤ 0.01). Treatment T2, T3, and T4 led to reductions in PM2.5 by 12.1%, 19.3%, and 31.7%, respectively, and in small particle concentrations (particle size >0.5 μm) by 18.0%, 21.1%, and 32.4%, respectively. However, no significant differences were observed for PM10 and large particles (particle size >2.5 μm) (P < 0.10), though the data suggests potential reductions in PM10 (32.7%) and large particles (33.3%) by the T4 treatment. Similarly, there was no significant impact of treatment on NH3 reduction (P = 0.712), possibly due to low NH3 concentration (<2 ppm) and low LMC (<13%) among treatment rooms. Electricity consumption was significantly related to the length of the EPI system (P ≤ 0.01), with longer lengths leading to higher consumption rates. Overall, a longer-length EPI corona pipe is recommended for better air pollutant reduction in CF housing. Further research should focus on enhancing EPI technology, assessing cost-effectiveness, and exploring combinations with other PM reduction strategies.

High-Density Lipoprotein Particles and Torque Teno Virus in Stable Outpatient Kidney Transplant Recipients.

Torque teno virus (TTV) is emerging as a potential marker for monitoring immune status. In transplant recipients who are immunosuppressed, higher TTV DNA loads are observed than in healthy individuals. TTV load measurement may aid in optimizing immunosuppressive medication dosing in solid organ transplant recipients. Additionally, there is a growing interest in the role of HDL particles in immune function; therefore, assessment of both HDL concentrations and TTV load may be of interest in transplant recipients. The objective of this study was to analyze TTV loads and HDL parameters in serum samples collected at least one year post-transplantation from 656 stable outpatient kidney transplant recipients (KTRs), enrolled in the TransplantLines Food and Nutrition Cohort (Groningen, the Netherlands). Plasma HDL particles and subfractions were measured using nuclear magnetic resonance spectroscopy. Serum TTV load was measured using a quantitative real-time polymerase chain reaction. Associations between HDL parameters and TTV load were examined using univariable and multivariable linear regression. The median age was 54.6 [IQR: 44.6 to 63.1] years, 43.3% were female, the mean eGFR was 52.5 (±20.6) mL/min/1.73 m2 and the median allograft vintage was 5.4 [IQR: 2.0 to 12.0] years. A total of 539 participants (82.2%) had a detectable TTV load with a mean TTV load of 3.04 (±1.53) log10 copies/mL, the mean total HDL particle concentration was 19.7 (±3.4) μmol/L, and the mean HDL size was 9.1 (±0.5) nm. The univariable linear regression revealed a negative association between total HDL particle concentration and TTV load (st.β = -0.17, 95% CI st.β: -0.26 to -0.09, p < 0.001). An effect modification of smoking behavior influencing the association between HDL particle concentration and TTV load was observed (Pinteraction = 0.024). After adjustment for age, sex, alcohol intake, hemoglobin, eGFR, donor age, allograft vintage and the use of calcineurin inhibitors, the negative association between HDL particle concentration and TTV load remained statistically significant in the non-smoking population (st.β = -0.14, 95% CI st.β: -0.23 to -0.04, p = 0.006). Furthermore, an association between small HDL particle concentration and TTV load was found (st.β = -0.12, 95% CI st.β: -0.22 to -0.02, p = 0.017). Higher HDL particle concentrations were associated with a lower TTV load in kidney transplant recipients, potentially indicative of a higher immune function. Interventional studies are needed to provide causal evidence on the effects of HDL on the immune system.

In situ measurements of perturbations to stratospheric aerosol and modeled ozone and radiative impacts following the 2021 La Soufrière eruption

Abstract. Stratospheric aerosols play important roles in Earth's radiative budget and in heterogeneous chemistry. Volcanic eruptions modulate the stratospheric aerosol layer by injecting particles and particle precursors like sulfur dioxide (SO2) into the stratosphere. Beginning on 9 April 2021, La Soufrière erupted, injecting SO2 into the tropical upper troposphere and lower stratosphere, yielding a peak SO2 loading of 0.3–0.4 Tg. The resulting volcanic aerosol plumes dispersed predominately over the Northern Hemisphere (NH), as indicated by the CALIOP/CALIPSO satellite observations and model simulations. From June to August 2021 and May to July 2022, the NASA ER-2 high-altitude aircraft extensively sampled the stratospheric aerosol layer over the continental United States during the Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) mission. These in situ aerosol measurements provide detailed insights into the number concentration, size distribution, and spatiotemporal variations of particles within volcanic plumes. Notably, aerosol surface area density and number density in 2021 were enhanced by a factor of 2–4 between 380–500 K potential temperature compared to the 2022 DCOTSS observations, which were minimally influenced by volcanic activity. Within the volcanic plume, the observed aerosol number density exhibited significant meridional and zonal variations, while the mode and shape of aerosol size distributions did not vary. The La Soufrière eruption led to an increase in the number concentration of small particles (&lt;400 nm), resulting in a smaller aerosol effective diameter during the summer of 2021 compared to the baseline conditions in the summer of 2022, as observed in regular ER-2 profiles over Salina, Kansas. A similar reduction in aerosol effective diameter was not observed in ER-2 profiles over Palmdale, California, possibly due to the values that were already smaller in that region during the limited sampling period in 2022. Additionally, we modeled the eruption with the SOCOL-AERv2 aerosol–chemistry–climate model. The modeled aerosol enhancement aligned well with DCOTSS observations, although the direct comparison was complicated by issues related to the model's background aerosol burden. This study indicates that the La Soufrière eruption contributed approximately 0.6 % to Arctic and Antarctic ozone column depletion in both 2021 and 2022, which is well within the range of natural variability. The modeled top-of-atmosphere 1-year global average radiative forcing was −0.08 W m−2 clear-sky and −0.04 W m−2 all-sky. The radiative effects were concentrated in the tropics and NH midlatitudes and diminished to near-baseline levels after 1 year.

Microphysical Characteristics of Snowfall on the Southeastern Tibetan Plateau

AbstractSnowfall on the Tibetan Plateau (TP) is crucially important to the hydrological cycle and glacier acceleration over the TP and surroundings. Climate and weather models are challenged by biases and uncertainties in representing microphysical characteristics of snowfall over TP. In order to bridge the gaps in our understanding of microphysical characteristics of snowfall on the southeastern TP (SETP), an integrated and systematic measurement is conducted at the South‐East Tibetan Plateau Station during the two winters of 2022–2023. It is the first time to conduct a long‐term measurement of microphysical characteristics of snowfall on the SETP. The major objective of this campaign was to collect cloud microphysical properties including, fall velocity, aspect ratio, and particle size distribution (PSD). The results show that the particle number concentration is less than 103 mm−1·m−3, which is one to two orders of magnitude smaller than that reported in low‐altitudes in eastern China. The shape parameter μ is mainly in the range 0–4, and the slope parameter λ is mainly in the range 3–7 mm−1, exceeding the values for eastern China. In heavy snowfall processes (snowfall rate (SR) exceeding 2 mm/hr), the collision‐coalescence process between snowfall particles is enhanced, and the number concentration of small particles decreases with SR, whereas that of large particles increases. A negative correlation was observed between the aspect ratio and the diameter of snowfall particles. The microphysical characteristics of snowfall will be used to improve the microphysical scheme and evaluate the representation of precipitation in the climate model.

Effect of intercalated and exfoliated graphite particles on the mechanical properties of polymer composite: A micromechanics-computational approach

This study investigated the effects of intercalation and exfoliation of the graphite flake particles on the mechanical properties of elastomeric composites using analytical, computational, and experimental techniques. Relying on the modified Eshelby and incremental Mori–Tanaka approach, a new micromechanics model was proposed to estimate Young’s modulus and develop a constitutive model for expanded graphite (EG)-filled elastomer in finite strain deformation. It was found that when the initial graphite flakes expanded, the actual volume fraction and ultimate aspect ratio of the dispersed particles significantly affected the mechanical properties of the EG-reinforced composites. The present model and subsequent predictions reflect the initial flake diameter, actual volume fraction, ultimate aspect ratio of the particles, and other convenient physical properties of the composite constituents. In addition, molecular dynamics simulations were performed to evaluate the elastic properties of the EG-Matrix interphase region using the COMPASS force field function. The MD results showed that Young’s modulus of the interphase region increased significantly as the quantity of the graphene layer increased. The micromechanics-constitutive model results were validated using the experimentally determined stress–strain relation of the composites. EG- and CB-elastomer nanocomposite specimens were fabricated and tested in the experimental program. Field emission scanning electron microscopy (FESEM) analysis of the cryo-fractured surfaces of the elastomer compounds showed good interactions between the constituents. Numerical computations indicated that the proposed model incorporating the new parameters could accurately predict the experiment at a small particle concentration.

A further study of history force effect on particle clustering in turbulence

We examine the effects of the history force on the preferential concentration of small particles in homogeneous isotropic turbulence under a wide range of the particle-to-fluid mass density ratio γ (from 0 to 10000) by direct simulations of the Navier–Stokes equations. As to the history integral kernel, we introduce two expressions: i.e., the classical Basset kernel valid only in the limit of creeping flow conditions and for short times, and the Mei–Adrian kernel (Mei and Adrian, 1992) applicable for finite Reynolds numbers and large times. It is revealed that the presence of the history force weakens the level of preferential concentration to some extent, specifically under the conditions of the mass density ratio of around 1.5–10 for heavy particles (e.g., solid particles in liquid) and smaller than 0.7 for light particles (e.g., bubbles in liquid) and that the overprediction of particle accumulation by neglecting the history force is much more remarkable for light particles. A comparison between the Basset kernel and the Mei–Adrian kernel has shown that the Basset kernel overestimates the history effect but only slightly.

The Effect of Carbohydrate Restriction on Lipids, Lipoproteins, and Nuclear Magnetic Resonance-Based Metabolites: CALIBER, a Randomised Parallel Trial.

Low-carbohydrate high-fat (LCHF) diets can be just as effective as high-carbohydrate, lower-fat (HCLF) diets for improving cardiovascular disease risk markers. Few studies have compared the effects of the UK HCLF dietary guidelines with an LCHF diet on lipids and lipoprotein metabolism using high-throughput NMR spectroscopy. This study aimed to explore the effect of an ad libitum 8-week LCHF diet compared to an HCLF diet on lipids and lipoprotein metabolism and CVD risk factors. For 8 weeks, n = 16 adults were randomly assigned to follow either an LCHF (n = 8, <50 g CHO p/day) or an HCLF diet (n = 8). Fasted blood samples at weeks 0, 4, and 8 were collected and analysed for lipids, lipoprotein subclasses, and energy-related metabolism markers via NMR spectroscopy. The LCHF diet increased (p < 0.05) very small VLDL, IDL, and large HDL cholesterol levels, whereas the HCLF diet increased (p < 0.05) IDL and large LDL cholesterol levels. Following the LCHF diet alone, triglycerides in VLDL and HDL lipoproteins significantly (p < 0.05) decreased, and HDL phospholipids significantly (p < 0.05) increased. Furthermore, the LCHF diet significantly (p < 0.05) increased the large and small HDL particle concentrations compared to the HCLF diet. In conclusion, the LCHF diet may reduce CVD risk factors by reducing triglyceride-rich lipoproteins and improving HDL functionality.

Applicability of deep learning optical flow estimation for PIV methods

Recently, there have been some attempts to introduce the method of deep learning-based optical flow(DL-based OF) into PIV measurements. These attempts have made it possible to estimate the flow field with higher accuracy and higher spatial resolution. The current mainstream deep-learning optical flow estimation method often requires a training set whose data distribution is closer to the real sample when completing the target task. However, there is a certain difference between the rigid body motion dataset commonly used in the field of computer vision and the fluid motion dataset in PIV measurements. Whether networks trained with rigid-body data can be directly applied to fluids has not been fully discussed. However, in existing attempts to introduce the DL-based OF method into the field of PIV measurement, the influence of the characteristics of the PIV particle image on the calculation results of the deep learning optical flow estimation (DL-based OF) has not been fully discussed. Therefore, the boundary conditions of the learning method for PIV calculation cannot be fully demonstrated. In this study, we selected the Flownet2 network, which is a classical baseline model on rigid body datasets, as a representative deep learning optical flow estimation method for experiments. Based on the characteristics of various particle images, this study generates a dataset with a wide range of parameters, such as particle density, particle diameter, sheet thickness, and maximum displacement, which are key to the generation of PIV simulation images and discusses the sensitivity of DL-based OF methods under extreme parameter conditions. This study compares (1) the model parameters trained using rigid body datasets such as Sintel, (2) the model parameters trained using synthetic PIV images, (3) the PIV-WIDIM method, and (4) the Optical Flow-Farneback method. The results reveal that the DL-based OF methods in (1) and (2) have a higher spatial resolution and estimation accuracy than the traditional methods in (3)] and (4). Training with the synthetic fluid dataset results in a smoother flow field in method (2)] compared with training with the rigid body dataset in method (1). In the case of limited training set parameters, Flownet2 can still be suitable for extreme conditions, such as small particle concentration, small particle diameter, insufficient particle brightness, or small particle displacement.

An association of CSF apolipoprotein E glycosylation and amyloid-beta 42 in individuals who carry the APOE4 allele

Carrying the apolipoprotein E (ApoE) Ɛ4 allele is associated with an increased risk of cerebral amyloidosis and late-onset Alzheimer’s disease, but the degree to which apoE glycosylation affects its development is not clear. In a previous pilot study, we identified distinct total and secondary isoform-specific cerebral spinal fluid (CSF) apoE glycosylation profiles, with the E4 isoform having the lowest glycosylation percentage (E2 > E3 > E4). In this work, we extend the analysis to a larger cohort of individuals (n = 106), utilizing matched plasma and CSF samples with clinical measures of AD biomarkers. The results confirm the isoform-specific glycosylation of apoE in CSF, resulting from secondary CSF apoE glycosylation patterns. CSF apoE glycosylation percentages positively correlated with CSF Aβ42 levels (r = 0.53, p < 0.0001). These correlations were not observed for plasma apoE glycosylation. CSF total and secondary apoE glycosylation percentages also correlated with the concentration of CSF small high-density lipoprotein particles (s-HDL-P), which we have previously shown to be correlated with CSF Aβ42 levels and measures of cognitive function. Desialylation of apoE purified from CSF showed reduced Aβ42 degradation in microglia with E4 > E3 and increased binding affinity to heparin. These results indicate that apoE glycosylation has a new and important role in influencing brain Aβ metabolism and can be a potential target of treatment.

Structural transitions in jammed asymmetric bidisperse granular packings

We study the local structural changes along the jamming transitions in asymmetric bidisperse granular packings. The local structure of the packing is assessed by the contact orientational order, tilde{Q}_{ell }, that quantifies the contribution of each contact configuration (Large–Large, Small–Small, Large–Small, Small–Large) in the jammed structure. The partial values of tilde{Q}_{ell } are calculated with respect to known ordered lattices that are fixed by the size ratio, delta , of the particles. We find that the packing undergoes a structural transition at phi _J, manifested by a sudden jump in the partial tilde{Q}_{ell }. Each contact configuration contributes to the jammed structure in a different way, changing with delta and concentration of small particles, X_{textrm{S}}. The results show not only that the packing undergoes a structural change upon jamming, but also that bidisperse packings exhibit local HCP and FCC structures also found in monodisperse packings. This suggests that the jammed structure of bidisperse systems is inherently endowed with local structural order. These results are relevant in understanding how the arrangement of particles determines the strength of bidisperse granular packings.Graphic abstract