Capillary Size Research Articles

An integrated simulation approach for demulsification of water-in-oil emulsions by medium coalescence

Medium coalescence, as a low energy consumption demulsification method, has been widely applied in many industries. During the water-in- oil emulsions flowing through medium bed, the dispersed water droplets not only collide and aggregate with each other, but also deposit and wet on the hydrophilic medium surface. Moreover, the formed large droplets may also breakup into small ones by the turbulent flow or the tiny fibers. Thus, an integrated approach is needed to predict the demulsification performance of water-in-oil (W/O) emulsion by medium coalescence. In this work, the population balance model (PBM) with considering Boltzmann motion and differential settlement was used to predict suspension droplets aggregation. The interaction between dispersed droplets and medium bed was calculated by a modified deposition model. Moreover, a published breakage model was selected to simulate the complex droplet breakage process. Then, the demulsification performance of W/O emulsion can be obtained by the variation of droplet size profile. To verify the integrated simulation approach, the existing experimental datasets were compared with the simulation results. After that, a sensitivity analysis was carried out to study parameters that affect the demulsification performance, such as flow velocity, capillary size, and continuous viscosity. The integrated approach proposed in this paper fills in the blank of the demulsification simulation of W/O emulsion by medium coalescence. It provides an in-depth understanding of the relationship between droplets behaviors and medium coalescence performance.

Evolution of the pore structure of pumice aggregate concrete and the effect on compressive strength

Abstract China possesses abundant pumice resources and thereby makes the utilization of pumice in the preparation of pumice aggregate concrete (PAC) a significant strategy for environmental protection and resource conservation. To obtain the effect of pumice pore structure variation on the compressive strength of PAC, PACs with strength classes LC20, LC30, and LC40 were prepared. Moreover, the pore structure of PAC was characterized using nuclear magnetic resonance to investigate the effect of pore structure variation on the compressive strength of PAC. Results showed that the higher the coarse aggregate content of PAC, the higher the percentage of large capillary and non-capillary pore sizes of PAC, corresponding to higher porosity and lower compressive strength. The hydration products in PAC continuously fill in the pore structure, the proportion of large capillary pores and non-capillary pore size gradually decreases, the proportion of small capillary pores and medium capillary pore size gradually increases, the pumice concrete matrix gradually becomes dense, and the compressive strength increases. The prediction model of the pore structure and compressive strength is established based on gray theory, and the relative error between predicted and tested values is not significant, which can effectively predict its compressive strength. It provides effective guidance for the engineering practical application of PAC.

State and role of water confined in cement and composites modified with metakaolin and additives

Cement as a porous material contains pores and cracks on the whole nanoscale forming an interconnected pore structure. Its interaction with water during the rehydration of cement plays a key role in every application, such as in nuclear waste treatment, where cement binders are commonly used for conditioning liquid radioactive waste. In the prediction of the long-term disposal the knowledge of water mobility and distribution in the formed porous cement matrix is essential.In this study we systematically investigate the effects of metakaolin and several components of the liquid phase (complexing agents, model ions, boric acid, etc.) on the hydrated solid structure by various nuclear magnetic resonance (NMR) methods. The novelty lies in the complex use of such non-conventional techniques that separately provide only partial information of the cement structure; however, the gained results complete each other to offer a new approach in the structural study under several conditions. Water mobility is deduced from NMR T2 relaxation distributions and D2O-H2O exchange diffusion measurements, and the conclusion on structural properties is supported by the macropore structure revealed from NMR cryoporometry and SEM (scanning electron microscopy) images, as well as by following the formation of pores and water domains in the curing process with NMR relaxometry. The results confirm that metakaolin was built into the CSH (calcium silicate hydrate) gel region without altering its mesoporous structure, however, it significantly decreased the capillary pore size and the diffusion coefficient of water. Complexing agent concentration between 2 and 20 g/l and the presence of model ions did not cause significant structural changes, while the rehydration decreased the size of capillary pores due to swelling.

Transport phenomena in microchannels in liquid–liquid extraction (LLE) systems operating in a slug flow regime—A review

AbstractIn the present work, the effects of various parameters (capillary size, shape, flow ratio, presence of additives, and presence of wall film) on both reactive and non‐reactive LLE systems are presented and analyzed. The literature data for a constant liquid flow ratio of 1 (Qc/QD = 1) has been correlated to give rise to two empirical correlations relating the Sherwood number (Sh), Reynolds number (Re), capillary number (Ca), and Schmidt number (Sc) have been developed for 0.1 < Re < 10 and 10 < Re < 200. The concept of j‐factor for micro‐channels has been introduced and named as Pandit–Kunzru–Ganguli analogy. Three new dimensionless numbers have been introduced, namely Pandit number (), Ganguli number , and Kunzru number (). The j‐factor is found to be a strong function of Capillary number for 10 < Re < 200 while it is a strong function of surface renewal for 0.1 < Re < 10. Empirical correlations to calculate j‐factor as a function of Re or Weber number (We) are also presented. Recommendations for future work have been presented based on the review in the present work.

Acceleration of the Development of Microcirculation Embolism in the Brain due to Capillary Narrowing.

Cerebral microvascular obstruction is critically involved in recurrent stroke and decreased cerebral blood flow with age. The obstruction must occur in the capillary with a greater resistance to perfusion pressure through the microvascular networks. However, little is known about the relationship between capillary size and embolism formation. This study aimed to determine whether the capillary lumen space contributes to the development of microcirculation embolism. To spatiotemporally manipulate capillary diameters in vivo, transgenic mice expressing the light-gated cation channel protein ChR2 (channelrhodopsin-2) in mural cells were used. The spatiotemporal changes in the regional cerebral blood flow in response to the photoactivation of ChR2 mural cells were first characterized using laser speckle flowgraphy. Capillary responses to optimized photostimulation were then examined in vivo using 2-photon microscopy. Finally, microcirculation embolism due to intravenously injected fluorescent microbeads was compared under conditions with or without photoactivation of ChR2 mural cells. Following transcranial photostimulation, the stimulation intensity-dependent decrease in cerebral blood flow centered at the irradiation was observed (14%-49% decreases relative to the baseline). The cerebrovascular response to photostimulation showed significant constriction of the cerebral arteries and capillaries but not of the veins. As a result of vasoconstriction, a temporal stall of red blood cell flow occurred in the capillaries of the venous sides. The 2-photon excitation of a single ChR2 pericyte demonstrated the partial shrinkage of capillaries (7% relative to the baseline) around the stimulated cell. With the intravenous injection of microbeads, the occurrence of microcirculation embolism was significantly enhanced (11% increases compared to the control) with photostimulation. Capillary narrowing increases the risk of developing microcirculation embolism in the venous sides of the cerebral capillaries.

Heart failure, female sex and atrial fibrillation are the main drivers of atrial cardiomyopathy in cardiac surgery patients: results from the CATCH ME consortium

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): CATCH ME: Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly Background Atrial cardiomyopathy is emerging as independent prognostic factor in cardiovascular disease. Fibrotic remodeling, cardiomyocyte hypertrophy and a reduction in capillary density are histological hallmarks of atrial cardiomyopathy. The contribution of etiological factors to atrial cardiomyopathy has not been robustly quantified. Purpose To quantify the relation between histological features of atrial cardiomyopathy and the clinical profile of patients. Methods We examined left (LA, n=91) and right (RA, n=75) atrial appendages sampled from a European cohort of patients undergoing cardiac surgery. Quantification of histological cardiomyopathy features was performed a recently developed and validated imaging analysis algorithm following myocardial triple staining with wheat germ agglutinin (WGA), CD31 and vimentin. The contributions of AF, heart failure (HF), sex, age, and 4 principal components accounting for confounding clinical characteristics to over-all and endomysial fibrosis were determined in a multivariate model. K-means clustering of 6 atrial histological features was performed to identify different types of remodeling. Results LA samples showed less fibrosis (p<0.001), a higher capillary density (p<0.05), a smaller capillary size (p<0.05), and larger cardiomyocytes (p<0.01) than RA samples. In both LA and RA, persistent AF was associated with endomysial fibrosis, while over-all fibrosis was not. Men had larger cardiomyocytes (LAA), while women had a higher degree of endomysial fibrosis (LA). Heart failure patients had more endomysial and over-all fibrosis (LA), a higher capillary density (LA) and capillary size (LA/RA). Samples clustered into 2 distinct clusters. One cluster showed fibrotic cardiomyopathy, with more endomysial (p<0.001) and overall fibrosis (p<0.001), more fibroblasts (p<0,001) and a higher capillary density (p<0.001). The other cluster showed hypertrophic cardiomyopathy, with hypertrophic cardiomyocytes (p<0.001). Patients with fibrotic cardiomyopathy were more often female (LA and RA, p<0.003) and had more often persistent AF (LA, p=0.031) or heart failure (LA, p<0.001). Patients with hypertrophic cardiomyopathy were more often male (LA and RA, p<0.003). Conclusions Fibrotic cardiomyopathy is associated with female sex, persistent AF and heart failure while hypertrophic cardiomyopathy more often occurs in men. More research is needed to establish whether treatment of AF and heart failure prevents the development of atrial cardiomyopathy.

MP-453085-5 ATRIAL FIBRILLATION, FEMALE SEX AND HEART HAILURE ARE THE MAIN DRIVERS OF ATRIAL CARDIOMYOPATHY IN CARDIAC SURGERY PATIENTS: RESULTS FROM THE CATCH ME CONSORTIUM

Atrial cardiomyopathy is emerging as independent prognostic factor in cardiovascular disease. Fibrotic remodeling, cardiomyocyte hypertrophy and a reduction in capillary density are histological hallmarks of atrial cardiomyopathy. The contribution of etiological factors to atrial cardiomyopathy has not been robustly quantified. To quantify the relation between histological features of atrial cardiomyopathy and the clinical profile of patients. We examined left (LAA, n=91) and right (RAA, n=75) atrial appendages sampled from a European cohort of patients undergoing cardiac surgery. Quantification of histological cardiomyopathy features was performed using a recently developed and validated imaging analysis algorithm following myocardial triple staining with wheat germ agglutinin (WGA), CD31 and vimentin. The contributions of AF, heart failure (HF), sex, age, and 4 principal components accounting for confounding clinical characteristics to over-all and endomysial fibrosis were determined in a multivariate model. K-means clustering of 6 atrial histological features was performed to identify different types of remodeling. LAA samples showed less fibrosis (p<0.001), a higher capillary density (p<0.05), a smaller capillary size (p<0.05), and larger cardiomyocytes (p<0.01) than RAA samples. In both LAA and RAA, persistent AF was associated with endomysial fibrosis, while over-all fibrosis was not. Men had larger cardiomyocytes (LAA), while women had a higher degree of endomysial fibrosis (LAA). Heart failure patients had more endomysial and over-all fibrosis (LAA), a higher capillary density (LAA) and capillary size (LAA/RAA). Samples clustered into 2 distinct clusters. One cluster showed fibrotic cardiomyopathy, with more endomysial (p<0.001) and overall fibrosis (p<0.001), more fibroblasts (p<0,001) and a higher capillary density (p<0.001). The other cluster showed hypertrophic cardiomyopathy, with hypertrophic cardiomyocytes (p<0.001). Patients with fibrotic cardiomyopathy were more often female (LAA and RA, p<0.003) and had more often persistent AF (LAA, p=0.031) or heart failure (LAA, p<0.001). Patients with hypertrophic cardiomyopathy were more often male (LAA and RAA, p<0.003). Fibrotic cardiomyopathy is associated with female sex, persistent AF and heart failure while hypertrophic cardiomyopathy more often occurs in men. More research is needed to establish whether treatment of AF and heart failure prevents the development of atrial cardiomyopathy.

A Model for Oxygen Transport from Blood in Microvessels to Tissue

Oxygen is vital for cellular energetics and metabolism in the human body. Blood transports oxygen to the tissues with hemoglobin in red blood cells playing a key role in the transportation of oxygen. To account for the Fåhraeus and Fåhraeus–Lindqvist effects, we use Haynes marginal zone concept, which subdivides each microvessel into a cell free layer surrounding a core region of uniform red blood cells concentration. The marginal zone concept is used to develop a steady state model for the transport of oxygen from blood to tissue where chemical reaction of oxygen occurs to produce energy. The approach is based on fundamentals of fluid flow and mass transfer in the two zones while accounting for the role of hemoglobin in the transport process and including mass transfer and chemical reaction in the tissue to produce energy using the Krogh cylinder concept. In contrast to transport modeling of solutes such as glucose, the present model includes the key role of hemoglobin in the transport of oxygen from blood to tissue. The model is analytical and provides analytical expressions for the oxygen level profiles in the blood cell free layer, the core zone, and the Krogh cylinder. The results are found to agree with published results in the literature for oxygen transport from blood in capillary size microvessel to its Krogh tissue cylinder. The model is not restricted to transport from capillaries and includes transport of oxygen from microvessels to tissue in general. Extensions of the model include further investigations in the case where changes in the blood microvessel or red blood cells occur due to pathological conditions.

Effectiveness of cleaning of sunflower oil with filter material made from composition of organic and inorganic fibers

In this study, the process of purification of sunflower oil per day using a filter material based on cellulose and inorganic fiber basalt fiber obtained from annual plants was studied. Studies have shown that sunflower oil obtained has improved a number of quality indicators. It was observed that the indicators such as transparency, color, acid number of the refined oil improved. Filtration is the process of separating solid particles from a liquid by passing a sufficiently thin and porous (fine-grained) barrier. The liquid passes through the pores, i.e. the capillaries of the filter material, and as the size of the suspended particles is larger than the capillary size, a precipitate forms on the surface of the fabric. Typically, this sediment itself has a major impact on the entire filtration process, as the material accumulates on the surface and serves as a self-filtering material.

Assessment of peritubular capillary rarefaction in kidneys of cats with chronic kidney disease.

Hypoxia is a key driver of fibrosis and is associated with capillary rarefaction in humans. Characterize capillary rarefaction in cats with chronic kidney disease (CKD). Archival kidney tissue from 58 cats with CKD, 20 unaffected cats. Cross-sectional study of paraffin-embedded kidney tissue utilizing CD31 immunohistochemistry to highlight vascular structures. Consecutive high-power fields from the cortex (10) and corticomedullary junction (5) were digitally photographed. An observer counted and colored the capillary area. Image analysis was used to determine the capillary number, average capillary size, and average percent capillary area in the cortex and corticomedullary junction. Histologic scoring was performed by a pathologist masked to clinical data. Percent capillary area (cortex) was significantly lower in CKD (median 3.2, range, 0.8-5.6) compared to unaffected cats (4.4, 1.8-7.0; P= <.001) and was negatively correlated with serum creatinine concentrations (r= -.36, P= .0013), glomerulosclerosis (r= -0.39, P= <.001), inflammation (r= -.30, P= .009), and fibrosis (r= -.30, P= .007). Capillary size (cortex) was significantly lower in CKD cats (2591 pixels, 1184-7289) compared to unaffected cats (4523 pixels, 1801-7618; P= <.001) and was negatively correlated with serum creatinine concentrations (r= -.40, P= <.001), glomerulosclerosis (r= -.44, P< .001), inflammation (r= -.42, P= <.001), and fibrosis (r= -.38, P= <.001). Capillary rarefaction (decrease in capillary size and percent capillary area) is present in kidneys of cats with CKD and is positively correlated with renal dysfunction and histopathologic lesions.

Synthesis of RGO/γ-Fe2O3 nanocomposite for the removal of heavy metals from aqueous solutions

Abstract Reduced graphene oxide/maghemite (RGO/γ-Fe2O3) material was successfully synthesized by combining the modified Hummers method with co-precipitation (RGO 10 wt.%). γ-Fe2O3 nanoparticles with a particle size of ∼14.8 nm were distributed on the surface of RGO sheets. Results of Brunauer–Emmett–Teller analysis showed that RGO/γ-Fe2O3 had a mesoporous structure and a narrow capillary size distribution curve at about 13 nm. The specific surface area of the RGO/γ-Fe2O3 was 168 m2·g−1. The RGO/γ-Fe2O3 nanocomposite was used to adsorb arsenic As(V) and a mixture of heavy metals (As(V), Cr(VI), Pb(II), and Fe(III)) in water. The maximum adsorption efficiency of As(V) reached 98.9% after 45 min with an adsorption capacity of 5.93 mg·g−1, higher than the simultaneous adsorption of the four metal ions. Competitive adsorption decreased in the order As(V), Cr(VI), Pb(II), and Fe(III). Therefore, RGO/γ-Fe2O3 could be used as an effective adsorbent to remove heavy metals from aqueous solutions.

Video-capillaroscopy, a promising tool for the clinical evaluation of patients with chronic venous insufficiency.

The cutaneous microangiopathy plays a key role in the development of the skin clinical lesions of venous insufficiency. Capillaroscopy allows a non-invasive observation of the superficial skin capillaries of the lower leg, which have previously been shown to be altered in patients with advanced venous disease. As it is now available in a friendly, easy to handle way through modern video devices, we report our findings in a short series of patients with C3-C5 chronic venous disorders using this technique. A total of 21 patients with venous insufficiency (C3-C5 on at least one leg) underwent a capillaroscopic examination of both legs and pictures recorded from the sites of the most severe venous skin lesions. This was performed with a CapXview handheld video-capillaroscope (×100 magnification), allowing easy manual measurement of maximum capillary bulk diameter and capillary density. Dramatic changes in capillary density, size, and shape were easily observed at the site of the venous skin lesions. A significant negative linear relationship was found between capillary density and the "C" classes (r = -0.45; P < 0.001). A significant negative correlation was also found between capillary density and bulk diameter (r = -0.52; P < 0.001). The area under the ROC curve for the mathematical prediction of venous skin changes by capillary density was 0.842, which shows the strength of the link between the microvascular and the clinical status. Video-capillaroscopy allows a direct observation of the cutaneous venous microangiopathy and provides the possibility to measure capillary density which allows its quantification. This simple to use technique shows the potential for a more precise follow-up and treatment evaluation of the cutaneous consequences of venous disease, which remains to be further investigated.

A fractal analytical model for Kozeny-Carman constant and permeability of roughened porous media composed of particles and converging-diverging capillaries

Seepage of particles in porous media has attracted considerable attention due to its extensive existence in nature. In this work, we have derived a novel fractal model for Kozeny-Carman (KC) constant and dimensionless permeability of roughened porous media composed of particles and converging-diverging capillaries. The model for KC constant and dimensionless permeability involves structural parameters of the media, such as porosity (Φ), fractal dimensions (dT and df), relative roughness (ξ), and the fluctuation amplitude (k) of capillary cross-section size. We systematically investigated the influence of the parameters above on the KC constant and the dimensionless permeability. An increase in fluctuation amplitude leads to an increase in the KC and a decrease in dimensionless permeability. In addition, the influence of the fluctuation amplitude on the KC constant and the dimensionless permeability will be more obvious with an increase in porosity. Furthermore, the effect of the fluctuation amplitude of capillary bundles on permeability satisfies the physical law. Comparisons with the experimental data in literature verifies the accuracy of the proposed fractal model. Thus, the proposed model may further reveal the physical mechanism of the fluid flow in roughened porous media, providing a better theoretical basis for various practical applications, such as petroleum engineering and fuel-cell industry.

Rate-Controlled Mercury Injection Experiments to Characterize Pore Space Geometry of Berea Sandstone

Interpretation of the relationship between heterogeneity and the flow in porous media is very important in increasing the recovery factor for an oil or gas reservoir. Capillarity for instance, controls fluids static distribution in a reservoir prior to production and remaining hydrocarbons after production commences. Therefore, capillary pressure data are used by petroleum engineers, geologists, and petrophysicists to evaluate production characteristics of petroleum accumulations. Conventional pressure-controlled mercury porosimetry produces an overall capillary pressure curve and pore throat size distribution data that provide little information about the porous medium structure and pore geometry. The present study provides information on three capillary pressure curves obtained from rate-controlled mercury injection porosimetry; one describes the larger pore spaces or pore bodies of a rock, another describes the smaller pores or pore throats that connect the larger pores, and a final curve which corresponds to the overall capillary pressure curve obtained from the conventional pressure-controlled mercury injection. An experimental constant-rate mercury injection apparatus was constructed that consists of a piston displacement pump, a computer controlled stepper motor drive and a core sample cell designed to minimize dead volume. The apparatus was placed in a glass chamber and subjected to an air bath to maintain a constant temperature of 27o C throughout the experiments. Then constant rate mercury injection experiments were performed on three Berea Sandstone core plugs. Results show that volume-controlled or rate-controlled porosimetry provides considerably more detailed data and information on heterogeneity and the statistical nature of pore space structure than the conventional pressure-controlled porosimetry as pressure fluctuations with time reveal menisci locations in pore bodies and pore throats. Moreover, pore size distributions based on volume-accessed pores and pore radii were obtained from the pressure versus saturation relationship.

Swept source optical coherence tomography and optical coherence tomography angiography for diagnosis and follow‐up of type 2 macular telangiectasia

AbstractPurpose: To report the contribution of swept source optical coherence tomography (SS‐OCT) and OCT‐angiography (OCTA) imaging findings in the diagnosis and the follow‐up of type 2 macular telangiectasia (MacTel 2).Methods: A retrospective study of eight eyes (five patients) with various stages of MacTel2. Clinical staging of MacTel 2 was performed based on SS‐OCT and OCTA.Results: The average age was 63 years old. The mean follow up was 33.6 months. A very early non‐proliferative stage was found in three eyes, an early non‐proliferative stage in three eyes and a late proliferative stage in two eyes. The most common findings on SS‐OCT were disruption of the inner segment‐outer segment (IS/OS) layer in all eyes, parafoveal hyporeflective retinal cavities in four eyes and superficial retinal crystals in three eyes. Two eyes showed irregularity of foveal contour and internal limiting membrane draping associated with retinal vascular channels connecting the superficial and deep retinal layers and forming retinal‐choroidal anastomosis. OCTA findings included capillary telangiectatic changes and enlargement of intercapillary spaces predominantly in deep capillary plexus (DCP) in comparison with superficial capillary plexus (SCP) in all eyes. Irregularity of capillary size in the perifoveal region of the DCP and SCP, predominantly temporal to the fovea, was found in five eyes. Circumferential capillary distortions and subretinal neovascularization at the level of the outer retina and choriocapillaris were detectable in two eyes. At the mean period of follow‐up, lesions were stable in two eyes, an extension of IS/OS disruption was noted in four eyes, parafoveal cavities' appearance and/or extension was found in two eyes and neovascular proliferation appeared in one eye.Conclusions: SS‐OCT and OCTA imaging features facilitate the diagnosis, staging and long‐term follow‐ up of MacTel 2. Further prospective studies are need to characterize the progressive and sequential nature of structural changes in this disease.

Seasonal and temporal variation in the placenta during melatonin supplementation in a bovine compromised pregnancy model.

Compromised pregnancies result in a poorly functioning placenta restricting the amount of oxygen and nutrient supply to the fetus resulting in intrauterine growth restriction (IUGR). Supplementing dietary melatonin during a compromised pregnancy increased uteroplacental blood flow and prevented IUGR in a seasonal-dependent manner. The objectives were to evaluate seasonal melatonin-mediated changes in temporal alterations of the bovine placental vascularity and transcript abundance of clock genes, angiogenic factors, and nutrient sensing genes in 54 underfed pregnant Brangus heifers (Fall, n = 29; Summer, n = 25). At day 160 of gestation, heifers were assigned to treatments consisting of adequately fed (ADQ-CON; 100% NRC; n = 13), nutrient restricted (RES-CON; 60% NRC; n = 13), and ADQ or RES supplemented with 20 mg/d of melatonin (ADQ-MEL, n = 13; RES-MEL, n = 15). The animals were fed daily at 0900 hours until day 240 where Cesarean sections were performed in the morning (0500 hours) or afternoon (1300 hours) for placentome collections. In both seasons, we observed a temporal alteration of the core clock genes in the cotyledonary tissue in a season-dependent manner. In the fall, ARNTL, CLOCK, NR1D1, and RORA transcript abundance were decreased (P ≤ 0.05) in the afternoon compared to the morning; whereas in the summer, ARNTL, PER2, and RORA expression were increased (P ≤ 0.05) in the afternoon. Interestingly, in both seasons, there was a concomitant temporal increase (P ≤ 0.05) of cotyledonary blood vessel perfusion and caruncular melatonin receptor 1A transcript abundance. Melatonin supplementation did not alter the melatonin receptor 1A transcript abundance (P > 0.05), however, in the summer, melatonin supplementation increased cotyledonary VEGFA, CRY1, and RORA (P ≤ 0.05) transcript abundance. In addition, during the summer the placentomes from underfed dams had increased average capillary size and HIF1α transcript abundance compared to those adequately fed (P ≤ 0.05). In conclusion, these data indicate increased cotyledonary blood vessel size and blood distribution after feeding to better facilitate nutrient transport. Interestingly, the maternal nutritional plane appears to play a crucial role in regulating the bovine placental circadian clock. Based on these findings, the regulation of angiogenic factors and clock genes in the bovine placenta appears to be an underlying mechanism of the therapeutic effect of dietary melatonin supplementation in the summer.

395 Young Scholar Award Talk: Melatonin: A Promising Therapeutic for Compromised Pregnancies

Abstract Poorly functioning placenta restricts oxygen and nutrient supply to the fetus resulting in fetal nutrient deficiency and intrauterine growth restriction. Intrauterine growth restriction dramatically increases neonatal mortality and those who survive are more prone to experience metabolic diseases such as cardiovascular diseases, hypertension, and type 2 diabetes in later life. Therefore, the placenta plays a critical role in the developmental origins of health and diseases. Currently, there is a vast effort evaluating the effects of compromised pregnancies such as maternal undernutrition, overnutrition, and heat stress on fetal development; however fewer studies have evaluated potential therapeutics to enhance placental efficiency and offspring performance. Melatonin, a hormone that modulates circadian rhythms, has shown to increase umbilical and uterine blood flow in pregnant dams. Moreover, a recent study observed that melatonin therapeutic effects during compromised pregnancies are seasonally dependent. Dietary melatonin supplementation to pregnant beef cattle increased uterine blood flow, rescued fetal weights, increased angiogenic factors in the placenta, and reduced vaginal temperatures in the summer, but not in the fall. The same study found that maternal nutrient restriction was more detrimental during the fall reducing uterine blood flow. Additionally, it was observed that dams that are nutrient restricted during the summer exerted a compensatory mechanism at the placentome level where they exhibited greater placentome vascularity and increased placental capillary size and angiogenic factors. Lastly, bovine placental circadian rhythms have been identified and interestingly, temporal increases in placental vascularity occur concomitantly with greater melatonin receptor 1A transcript abundance. In conclusion, these findings provide a better understanding of placental insufficiency and impaired fetal growth during maternal nutrient restriction, while temporal alterations in the placenta could lead to the development of proper guidelines for administration of placental blood flow therapeutics such as melatonin. Future studies should evaluate melatonin impacts on offspring organ development and potential for mitigating heat stress in livestock.

Improving the effectiveness of internal curing through engineering the pore structure of lightweight aggregates

A low absorption rate and a small thermal conductivity coefficient are the main targets in the preparation of traditional coarse lightweight aggregate (LWA). Fine LWA is generally used as internal curing materials and crushed from coarse LWA. Large pores or low water absorption will reduce the effectiveness of internal curing. In this study, a waste-based fine LWA with high water absorption (≥20%) has been made of bauxite tailings, silica fume, and paper sludge. The pore structure formation of fine LWA was analyzed. Time-dependent water absorption, water desorption, and pore structure of fine LWA were tested. Their effects on the early-aged hydration, autogenous shrinkage, pore structure, and compressive strength of high-strength mortars were studied. The results showed that different from the isolated and large pore structure of the expanded shale, fine LWA had a connected and fine pore structure of 200–2000 nm. It could absorb about 30.6% water by mass and quickly reaches saturation, and more than 95% of water absorbed was released at 97% relative humidity (RH). Fine LWA had a good water retention capacity and did not result in the delay of the main hydration. The capillary pore size of 20–50 nm increased and the total porosity reduced due to the increased degree of hydration. Compared to the high-strength mortars with the same mixing water content, fine LWA reduced the autogenous shrinkage of mortars by up to 88% and increased the strength of mortars by up to 2.5%.

A Novel Model of Counter-Current Imbibition in Interacting Capillaries with Different Size Distribution

The imbibition phenomenon widely exists in nature and industrial applications. It is of great significance to study the mechanism of imbibition and the influence laws of related factors. In this paper, based on the assumption of interacting capillaries, a capillary bundle model of counter-current imbibition is established. In addition, the characteristics of imbibition and the influences of capillary size and fluid viscosity are analyzed. The results show that water is imbibed into the smaller capillaries and expelled from the larger capillaries. The rate of the meniscus in water-imbibition capillaries is proportional to the square root of time. In the interacting capillaries, oil production by counter-current imbibition decreases and then increases gradually with the increase of the capillary diameter difference. When the total cross-sectional area of the capillary remains unchanged, the cross-sectional area of the total water-imbibition capillaries is affected by the size distribution of the capillaries. The larger the viscosity of the non-wetting phase, the more uneven the imbibition front, the lower the imbibition efficiency. The higher the viscosity of the wetting phase, the more uniform the imbibition front, and the higher the imbibition efficiency.

Simulation of a micron resolution capillary liquid scintillation detector for 14 MeV fusion neutrons

Aiming to improve the spatial resolution of a neutron imaging system (NIS) for 14 MeV fusion neutrons, an ideal micron resolution capillary detector filled with a high optical index liquid scintillator was simulated. A threshold for each capillary pixel and a threshold for each cluster were applied to suppress the gamma-induced background. In addition, by using a pattern recognition algorithm and an optimized Hough transform, the accuracy of determining the neutron impinging positions and the dynamic range of this detector were enhanced. For an ideal capillary array detector, the spatial resolution is expected as one capillary size of 20μm. The dynamic range of ∼1000 is reachable while the accuracy of neutron impinging position determination keeps better than 85%. The ionization quenching, light sharing and energy resolution of the detector were applied to the simulated data to understand the capillary array detector.