Lower Diameter Research Articles

Eversa transform 2.0 immobilized on a hydrophobic support enables the solvent-free almost quantitative esterification of the free fatty acids from soybean oil with neopentylglycol

The performance of Eversa Transform 2.0 (ETL) and lipase from Thermomyces lanuginosus (TLL) was compared in the solvent-free esterification of the free fatty acids (FFAs) from soybean oil with neopentylglycol (NPG) to produce NPG-diesters, which may be used as biolubricants. Enzymes were immobilized by interfacial activation on an octadecyl-coated methacrylate macroporous resin (C18) and compared to commercially immobilized TLL (Lipozyme® TL IM), free ETL and TLL. ETL@C18 surpassed the performance of all tested biocatalysts, reaching up to 98 % of FFAs conversion after 6 h of reaction at 50 °C and using a biocatalyst content of 9 wt% (related to the mass of FFAs). After optimization, the reactor temperature had a higher influence on the production of the NPG-diesters than the biocatalyst content, so that 45 °C and 3 wt% were determined to be the optimal values. Under such conditions, ETL@C18 retained approximately 88 % of its initial conversion into the NPG-diesters even after 10 consecutive reaction cycles. The biolubricant is composed mainly of NPG-diesters (∼91 %) and unreacted NPG (∼9 %), as confirmed by NMR analysis. The NPG-diesters exhibited a higher viscosity index (from 190.84 to 215.86) and oxidative stability (from 0.10 h to 1.34 h) than the starting material. The NPG-diesters biolubricant also exhibited a lower friction coefficient (0.049 against 0.064) and wear scar diameter (139.03 μm against 151.43 μm) than the 20W-50 mineral lubricant.

Towards a better understanding of xylem: Helical thickenings in vessels of woody angiosperms are associated with thinner cell walls and lower vessel diameter

Towards a better understanding of xylem: Helical thickenings in vessels of woody angiosperms are associated with thinner cell walls and lower vessel diameter

Microphysical characteristics of torrential predecessor rain events over the Yangtze River Delta Area and the related tropical cyclones

The precipitation structures and microphysical characteristics of predecessor rain events (PREs) over the Yangtze River Delta area and related tropical cyclones (TCs) from 2014 to 2019 were investigated using Dual-frequency Precipitation radar data from Global Precipitation Measurement (GPM) for drop size distributions (DSDs). Results showed that the total mean rain rate of PREs was larger than that of TCs, primarily due to higher convective and stratiform rain rates, with enhanced fractional coverage of convective rain in PREs. Examination of microphysical characteristics revealed that a greater quantity of small-sized droplets and a smaller quantity of medium- as well as large-sized droplets contributed towards PREs in comparison with TCs. The conclusion still holds when partitioning DSDs based on different precipitation rate categories. Further investigation of DSDs using gamma functions illustrated that precipitation in PREs had lower average mass-weighted diameters (Dm) and enhanced normalized number concentration (Nw) compared with TCs; partitioning precipitation into convective and stratiform components illustrated a larger Dm and lower Nw in TCs than PREs. The analysis of microphysical and thermodynamical processes using the reanalysis data indicates that relatively intense convective activity with drier conditions may be favorable to enhancing raindrop growth through collision-coalescence processes, as a result of larger Dm in TCs than PREs. The empirical relations (Z–R algorithms) applied in different rain regimes (stratiform, convective, and total PREs) revealed significant diversities, relying on weather conditions and geographical locations. Plain language summaryThe Yangtze River Delta area is an important economic belt in China. Under climate change, observed frequent occurrences of weather extremes of heavy rainfall and tropical cyclones (TCs) exert adverse effects on economic development in this region. Thus, a deep understanding of the mechanism of TCs torrential rainfall in the Yangtze River Delta area is urgently necessary. In this study, we investigated the precipitation patterns and microphysical characteristics of predecessor rain events (PREs) in the Yangtze River Delta region, and their association with TCs in the South China Sea-Western North Pacific Ocean (SCS-WNPO) area from 2014 to 2019. We found that PREs had a higher total mean precipitation rate than TCs. Further examination using gamma functions demonstrated that PREs exhibited lower average mass-weighted diameters (Dm) and higher normalized intercept parameters (Nw) than TCs. This pattern persisted when distinguishing between convective and stratiform precipitation components. We believe that our study makes a significant contribution to the literature because these results provide valuable insights into the distinct precipitation characteristics of PREs and TCs in the study region and contribute to a better understanding of tropical cyclone-related rainfall patterns, and act as a scientific basis for disaster mitigation.

Rate and risk factors of tip displacement of umbilical venous catheterization at different indwelling time points in preterm infants

Objectives: To investigate the rate and risk factors of tip displacement of umbilical venous catheterization (UVC) in preterm infants. Methods: This was a multicenter cohort study. Study population were preterm infants admitted to 44 tertiary hospitals in China between October 2019 and August 2021. Demographic information, general clinical data, UVC indwelling conditions and related complications were collected. The primary outcome was the rate of UVC tip displacement. The observation time points were 2 d and 7 d after UVC. They were grouped according to UVC displacement, gestational age, and birth weight. Binary Logistic regression was used to analyze the risk factors of UVC tip displacement. Results: The 2 086 preterm infants had a gestational age of (29.9±2.3) weeks and a birth weight of (1 248±298) g. There were 1 106 male preterm infants (53.0%). The rate of UVC displacement at 2 d and 7 d were 34.6% (721/2 086) and 33.6% (494/1 470), respectively, with no statistically significant difference (χ2=0.35, P=0.533). Univariate analysis indicated that male infants, small gestational age, low birth weight and small catheter diameter were all risk factors for UVC tip displacement at the 2 d time point (all P<0.05). Multivariate analysis showed that small catheter diameter was an independent risk factor for tip displacement at both 2 d (OR=0.47, 95%CI 0.34-0.66) and 7 d (OR=0.39, 95%CI 0.25-0.59) time points (both P<0.001). Conclusions: The rate of UVC tip displacement is high in preterm infants. It should be avoided to deliberately select a small diameter catheter for UVC, and pay attention to the imaging monitoring of the tip position after UVC.

Antifungal activity of 2-chloro-5-trifluoromethoxybenzeneboronic acid and inhibitory mechanisms on Geotrichum candidum from sour rot Xiaozhou mustard root tuber

Xiaozhou mustard (Brassica napiformis) root tuber, a traditional fermented vegetable, has a long history in Rongan County, Guangxi Province. However, the frequent occurrence of root tuber sour rot by Geotrichum candidum (G. candidum) has seriously reduced Xiaozhou mustard production and quality in recent years. The objective of the present study is to investigate the antifungal efficacy of 2-chloro-5-trifluoromethoxybenzeneboronic acid (Cl-F-BBA) against G. candidum and its possible mechanisms. The results revealed that a concentration of 0.25 mg/mL Cl-F-BBA completely halted mycelial growth and spore germination. Furthermore, a slightly lower concentration of 0.20 mg/mL was sufficient to compromise the integrity of the plasma membrane in mycelia and mitochondria, leading to a reduction in respiratory rate, activities of malate dehydrogenase (MDH), and succinate dehydrogenase (SDH), ATP content, and energy charge. This concentration also significantly disordered antioxidant metabolism, resulting in the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), and caused intracellular leakage in mycelia. In vivo experiments further demonstrated that Xiaozhou mustard root tubers treated with Cl-F-BBA exhibited markedly lower decay rates and lesion diameters compared to the control group. In summary, Cl-F-BBA presents a promising solution for controlling root tuber sour rot in Xiaozhou mustard caused by G. candidum.

Early Detection of Arteriovenous Fistula Problems among Pediatric Hemodialysis Patients

Abstract Background End stage Kidney disease (ESKD) is a major problem that is related to development of inflammation. Establishment of vascular access (VA) in the form of arteriovenous fistula (AVF) is mandatory to conduct efficient hemodialysis (HD). VA complications are one of the main causes of increase in morbidity and mortality in ESKD patients, which needs to be monitored regularly. Objective to evaluate the value of duplex ultrasound (DUS) and inflammatory markers (high sensitivity (hs) CRP, IL10, TNF) in early detection of vascular access complications in pediatric ESKD patients on regular HD. Methods This observational and interventional study was carried on 59 pediatric patients on regular HD at the PediatricDialysis Unit, Children’s Hospital, Ain Shams University, where DUS and serum level of inflammatory markers (hs-CRP, IL10, and TNF) were assessed once at time of enrollment (1) and the second at the time of early clinical suspicion of VA complication (2) which was detected by any abnormalities in physical examination. Results The study comprised 59 pediatric patients on regular HD, their mean (± SD) age was 13.97 (±2.65) years, 39 (56.5%) of them were males. The most common etiology of CKD was congenital anomalies of kidney and urinary track (CAKUT). Complications of the VA were reported in 55.9% of our studied patients, which include thrombosis, aneurysm, stenosis, early VA failure, pseudoaneurysm and perivascular hematoma, where thrombosis was the most frequent (28.8%), and was confirmed by DUS. AVF diameter (2), and flow volume (2) were significantly lower among patients with AVF thrombosis. The mean serum level of hs CRP was significantly elevated at the time of early clinical suspicion of AVF stenosis, and was confirmed by DUS, in comparison to its baseline level at time of enrollment of the study (0.08±0.08, 0.16±0.28 ng/mL, respectively, p = 0.04), serum IL10(1&amp;2) and TNF (2) were higher in this group. Early VA failure were reported in patients who had lower AVF diameter (1), PSV (1), EDV(1&amp;2),flow volume (1&amp;2), and higher AVF diameter (2), PSV (2). Conclusion DUS and hs-CRP are useful tools for early detection and, hence the management of AVF complications.

Enhancing mechanical properties of cellulose acetate/carbon black nanofibers for oil spill cleanup

Oil contamination caused by various oil-related industries and domestic usage is one of the major global challenges that threaten the environment. Therefore, employing efficient and environmentally friendly methods for oil removal from oily water is crucial. Nanofibers offer suitable mediums for such applications due to their low fiber diameter and high surface area. Herein, mechanically enhanced carbon black (CB) loaded-cellulose acetate (CA) nanofiber mats were developed for oil removal applications. Initially, CA/CB nanofibers were fabricated from 15% wt. CA solutions containing 2% wt. CB. To improve the mechanical properties, the samples were treated in an ethanol:acetone bath for 2 and 4h. Increasing post-treatment duration increased the nanofiber diameters from 438 nm to 601 nm and decreased porosities from 75% to 66%. The post-treatments improved the mechanical properties of the samples and the highest modulus was achieved as 20.85 MPa. The water and oil contact angles increased from 86° to 102° and 61° to 80°, respectively. The liquid absorption and retention capacities of the samples were evaluated by immersing them in water, seawater, waste oil, and their emulsions. Despite their lower initial oil absorption compared to the non-treated one, post-treated samples still retained large amounts of oil at the end of 24 h.

Routing and assignment of wavelengths for bicube in linear array WDM optical networks

Optical networks leverage the principles of optical communication to transmit data over long distances with high bandwidth and low signal loss. They have lots of applications supporting the backbone of modern communication systems. Wavelength division multiplexing (WDM) enables the simultaneous transmission of many signals with distinct wavelengths via one optical fiber, thereby increasing the overall capacity of the network. One of the significant aspects of designing and managing WDM optical networks involves routing and wavelength assignment (RWA), especially as the demand for high-capacity, low-latency communication continues to grow in recent times. Bicube networks possess many attractive properties, one of the salient features being low diameter as compared to a hypercube. Hence, research using bicube topology is very much prevalent in the last few years. In this paper, we use the technique of congestion to study the RWA problem for bicube in a linear array optical network that uses WDM technology. We also propose algorithms to efficiently compute the minimum number of wavelengths.

Ratio of pulmonary artery diameter to ascending aortic diameter and its association with right ventricular failure after left ventricular assist device implantation

BackgroundSeveral invasive hemodynamic parameters help predict right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation. However, prediction using non-invasive parameters alone has not been established. The ratio of the diameters of the pulmonary artery (PAD) to those of the ascending aorta (AoD) may indicate past hemodynamic load and cardiac dysfunction. We aimed to investigate a predictive model for RVF after LVAD implantation using non-invasive parameters including PAD/AoD ratio. MethodsWe studied 141 patients who underwent primary LVAD implantation and 117 healthy individuals with computed tomography (CT) data. RVF was defined as the need for a subsequent right ventricular assist device or intravenous inotrope administration for more than 30 days after LVAD implantation. The PAD/AoD ratio was measured at the level of the pulmonary artery bifurcation on the CT transaxial slices. ResultsRVF was observed in 29 patients. The correlation between PAD and AoD differed among healthy individuals, patients with and without RVF. Patients with RVF had higher total bilirubin and log brain natriuretic peptide (BNP) levels, a lower left ventricular end-diastolic diameter (LVDd) index, and a higher PAD/AoD ratio than those without RVF. Decision tree analysis indicated that the subgroup with a high PAD/AoD ratio (≥1.09) and a small LVDd index (<35.4 mm/m2) showed the highest probability of RVF (100 %), while the subgroup with a low PAD/AoD ratio (<1.09) and low log BNP (<2.79) showed the lowest probability of RVF (1 %). ConclusionCombining non-invasive parameters with the PAD/AoD ratio can predict RVF with high accuracy.

High birefringent slotted core slotted cladding porous core PCF for THz waveguide

A novel design featuring a porous core photonic crystal fiber (PC-PCF) is proposed in this paper for terahertz (THz) waveguide application. This work uses finite element method (FEM) and a boundary condition related to perfectly matched layer (PML) for analyzing the guiding properties. This methodology is supported by a fiber type featuring a slotted core and slotted cladding, utilizing Zeonex as the material. It offers high birefringence valued at 0.0978, small confinement loss of 10−14 dB/cm, a meager amount of effective material loss (EML) valued at 0.011697 dB/cm and a very high core power fraction (CPF) of 67.156%. Additionally, it shows a flattened pattern of dispersion measuring 0.4 ± 0.2 ps/THz/cm at an extensive frequency range of 0.5 THz to 2 THz. Other significant waveguide properties: effective refractive index, numerical aperture (NA), V-parameter, effective area, spot size, and beam divergence of the suggested fiber are numerically analyzed and conferred thoroughly. Regarding its mode of operation, the proposed fiber primarily functions in multimode, but it can also operate in single mode for higher porosity levels and lower core diameters. This unique characteristic renders the proposed PC-PCF structure well-suited for a broad range of applications, offering versatility as to its mode of operation.

Influencing Factors of Oil Droplets Accumulation on the Lower Surface of Corrugated Plate

ABSTRACTThe corrugated plate is the core component of a corrugated plate oil–water separator, which significantly influences oil–water separation efficiency. To study the influencing factors of oil droplets floating and coalescing on the lower surface of the corrugated plate, numerical simulation and experiments were used to analyze the effects of wave ratio, lower plate surface contact angle, oil viscosity, and oil droplet diameter on the floating of oil droplets on the coalescence of oil droplets. The results show that a moderate wave height ratio, lower contact angle, lower oil phase viscosity, and larger oil droplet diameter have better oil droplet agglomeration and floating effect. In the set parameter range, when the wave height ratio of the plate is 0.5, the contact angle of the lower surface of the plate is 30°, the oil phase viscosity is 0.0048 Pa s, and the oil droplet diameter is 8 mm, the oil droplet coalesces and floating effect are the best.

Quantitative eco-anatomical analysis reveals distinctive stem traits of six Cannabis sativa cultivars in Rif Mountains (Northern Morocco)

Cannabis sativa stands out as an important crop with significant socioeconomic importance in the Rif Mountains of North Morocco. Recently the number of new cultivars developed in this region has gradually increased for different purposes. In this current study, we delve into the eco-anatomical characteristics of stems across six of the most prevalent Cannabis sativa cultivars in Morocco: ‘Avocat’, ‘Beldiya’, ‘Critical Plus’, ‘Industriel’, ‘Khardala’, and ‘Mexicana’. The investigation encompasses the measurement and analysis of six key eco-anatomical traits: plant height, stem diameter, vessel size, vessel density, number of vessels joined in radial files, and coefficient of hydraulic conductivity. Our aim is to elucidate the variations among these cultivars and underscore their agricultural and ecological relevance. Through anatomical examinations of stem cross-sections, our findings reveal notable disparities and distinctive features among the cultivars. The ‘Khardala’ cultivar exhibits the highest values across most measured eco-anatomical traits, while ‘Beldiya’ and ‘Mexicana’ show similar trait values, particularly with low stem diameter and vessel density. In contrast, ‘Industriel’ stands out with the lowest vessel size and highest vessel density. ‘Critical Plus’ and ‘Avocat’ closely resemble ‘Khardala’ in vessel size and stem diameter. Regarding hydraulic conductivity, ‘Khardala’ ranks highest, followed by ‘Avocat’ and ‘Critical Plus’, while ‘Industriel’ registers the lowest. Our findings underscore increased water demand and uptake potential in ‘Khardala’, ‘Critical Plus’, and ‘Avocat’, contrasting with ‘Industriel’, ‘Beldiya’, and ‘Mexicana’. Anatomical diversity among Cannabis cultivars in our study likely stems from genetic lineage and ecological adaptation.

Upcycling Post-Consumer Paint Pail Plastic Waste.

The need for ending plastic waste and creating a circular economy has prompted significant interest in developing a new family of composite materials through recycling and recovery of waste resources (including bio-sourced materials). In this work, a family of natural fiber-reinforced plastic composites has been developed from paint pail waste recycled polypropylene (rPP) and waste wool fibers of different diameter and aspect ratio. Composites were fabricated by melt processing using polypropylene-graft-maleic anhydride as a compatibilizer. The internal morphology, interfacial and thermal characteristics, viscoelastic behavior, water sorption/wettability, and mechanical properties of composites were studied using electron microscopy, high-resolution synchrotron Fourier transform infrared microspectroscopy, thermal analysis, rheology, immersion test, contact angle measurement, tensile test and flexural test. The composite matrix exhibited an internal morphology of coalescent micro-droplets due to the presence of polyethylene and dry paint in the rPP phase. In general, the rheological and mechanical properties of the composites comprising higher-aspect-ratio (lower diameter) fibers exhibited relatively superior performance. About an 18% increase in tensile strength and a 39% increase in flexural strength were measured for composites with an optimal fiber loading of 10 wt.%. Interfacial debonding and fiber pull-out were observed as the main failure mechanism of the composites. The developed composites have potential for applications in automotive, decking, and building industries.

Biological tissue for transcatheter aortic valve: The effect of crimping on fatigue strength

Transcatheter aortic valve replacement (TAVR) has become today the most attractive procedure to relieve patients from aortic valve disease. However, the procedure requires crimping biological tissue within a metallic stent for low diameter catheter insertion purpose. This step induces specific stress in the leaflets especially when the crimping diameter is small. One concern about crimping is the potential degradations undergone by the biological tissue, which may limit the durability of the valve once implanted. The purpose of the present work is to investigate the mechanical damage undergone by bovine pericardium tissue during compression and analyze how this degradation evolves with time under fatigue testing conditions. Pericardium 500 μm thick pericardium ribbons (5 mm large, 70 mm long) were crimped down to 12 Fr for 30 and 50 min within a metallic stent to replicate the heart valve crimping configuration. After crimping, samples underwent cyclic fatigue flexure and pressure loading over 0.5 Mio cycles. Samples were characterized for mechanical performances before crimping, after crimping and after fatigue testing in order to assess potential changes in the mechanical properties of the tissue after each step. Results bring out that the ultimate tensile strength is not modified through the process. However an increase in the modulus shows that the crimping step tends to stiffen the pericardium. This may have an influence on the lifetime of the implant.

The effect of the liposomal form of alteplase on the effectiveness of thrombolysis in coronary arteries in acute myocardial infarction

A liposomal (Lip) formulation of tissue plasminogen activator, alteplase (AlT), has been developed. The quantitative and qualitative composition of the liposomes, as well as their physicochemical properties and proteolytic activity, have been studied in relation to the thrombolytic liposomal form. It was determined that a formulation consisting of liposomes with a phosphatidylcholine/cholesterol ratio of 1.5 : 1, and lipids/alteplase ratio of 1 : 1, is optimal for treating acute myocardial infarction (AMI) in experimental models. At different component ratios, liposomes had a negative zeta potential value greater than 30 mV, indicating their aggregative stability, even after storage for two days at 20 degrees Celsius. Liposomes derived from soy phosphatidylcholine showed greater colloidal stability with a zeta potential of approximately –57 mV and a lower hydrodynamic diameter of approximately 140 nanometers, compared to liposomes derived from egg phosphatidylcholine, which had a zeta potential around –35.4 mV and a hydrodynamic diameter around 220 nanometers. The initial content of free AlT in the liposome supernatant from egg phosphatidylcholine (Lipeg) was 15.0 ± 4.0 %. During the incubation period of 4 days, the concentration of free AlT decreased to 9.0 ± 4.5 %. In contrast, in liposomes derived from soy phosphatidylcholine (LipS), the content of free AlT increased from 11.0 ± 4.5 % to 32.5 ± 6.0 % over the same incubation period. The value of the proteolytic activity of tissue plasminogen activator (tPA) in the compositions of Lipeg(AlT) and Lips (AlT) depends on the type of phosphatidylcholine. The initial tPA activity in Lipeg (AlT) was 36.0 %, and after 1 day, it increased to 45 %. In Lips (AlT), the initial activity was 61.0 % and increased to 66 % after 1 day. When using the liposomal form of alteplase for delivery into the coronary arteries of rats with acute myocardial infarction (AMI), a more complete fibrin lysis is noted compared to animals receiving the native form of the drug. The developed system of targeted delivery of alteplase using soy liposomes has been shown to significantly improve the degree of coronary artery lumen restoration by more than 15 %, compared to the use of a conventional drug (p &lt; 0.05).

Abstract 65: Postpartum Alterations of Middle Cerebral Artery Reactivity and Hemodynamics in a Transgenic Rat Model of Preeclampsia

Evidence suggests that cerebrovascular disease is a leading cause of morbidity and mortality in women with preeclampsia (PE), however the mechanisms are unknown. In a transgenic rat displaying PE-like syndrome (TGA-PE: female transgenic for angiotensinogen mated to male transgenic for renin), we have shown postpartum alterations in cerebrovascular hemodynamics suggesting dysfunctional autoregulation. We hypothesize that impaired middle cerebral artery (MCA) reactivity contributes to the cerebrovascular dysfunction in this model. High frequency ultrasound was used to determine the pulsatility index (PI) of left MCA (LMCA). Vascular responses were studied in isolated segments of LMCA from SD (n= 12) and TGA-PE (n=8) two months post-delivery. Arteries were mounted on a Multi-Wire Myograph for determination of isometric force (USA-DMT). The contractile responses to K + 75 mM and endothelin-1 (ET-1, 10 -11 -10 -7 M) were measured in basal tone. Vasodilatory responses to acetylcholine (ACh, 10 -11 -10 -4 M) were determined in arteries pre-constricted with the thromboxane agonist U46619 (10 -7 M); the maximal response ( R MAX ) and sensitivity (pD 2 =-Log[EC 50 ]) were analyzed. Our data show that systolic blood pressures were elevated in TGA-PE versus SD at 2 months post-delivery (144.9±2.7 vs. 118.4±2.5, p&lt;0.05; n=10-19). However, the PI was lower in TGA-PE vs. SD (0.96±0.05 vs. 1.31±0.06; p&lt;0.05, n=8-13). No differences in basal tone of MCA segments were observed, whereas TGA-PE arteries displayed a lower optimal diameter (175±4 μm vs. 217±4 μm; p&lt;0.05) and a lower response to K + (0.85±0.11 vs. 1.29±0.1 mN/mm; p&lt;0.05) compared to SD. Vasodilatation to acetylcholine was similar (ACh MAX : 79±8 vs. 70±9%) with a lower sensitivity (pD 2 : 5.2±0.1 vs. 6.7±0.4; p&lt;0.05) in TGA-PE. The contractile response to ET-1 was increased in TGA-PE arteries (ET-1 MAX : 159±7 vs. 129±6 % K MAX ; p&lt;0.05) with no differences in sensitivity (pD 2 : 8.8±0.1 vs. 8.9±0.1). Our data demonstrate structural and functional differences in MCA from TGA-PE vs. SD at 2 months postpartum. In addition to a smaller functional diameter, a lower non-receptor dependent contraction may explain the lower resistance of MCA observed in the preeclamptic model. We conclude that attenuated vasodilatory and increased contractile responses of MCA could promote cerebrovascular dysfunction in this model, and that these adaptations may contribute to cerebrovascular pathology in postpartum preeclamptic state. Supported by NIH 1R01HL155420

O59 INFLUENCE OF CIRCADIAN BLOOD PRESSURE PATTERN ON RIGHT VENTRICULAR STRUCTURE AND FUNCTION IN PATIENTS WITH ARTERIAL HYPERTENSIION

Background and Objective: It is well proven, that arterial hypertension affects left side of the heart and causes its remodeling and functional changes. Since heart works as a unit and has ventricular interdependence, aim of the study was to assess influence of hypertension and circadian blood pressure (BP) profile on a right ventricular structure and function. Methods: 75 hypertensive patients (57.13±7.27 y/o) and 25 normotensive control subjects (57.56±7.55 y/o) were involved in a study. All of them were males without history of coronary artery disease, cerebrovascular or peripheral artery disease, obstructive lung disease, significant valvular heart disease or heart failure. All of them were either lifetime nonsmokers, or stopped smoking more than 5 years. All the patients underwent to 24-hour ambulatory BP monitoring and heart ultrasound with tissue doppler imaging. Results: Hypertensive patients with dipper circadian BP profile had higher TAPSE (19±1.586 vs 17.708±2.857; P&lt;0.05), higher right ventricular ejection fraction (55.103±4.597 vs 47.829±14.605; P&lt;0,005) and lower right ventricular outflow tract diameter (29.985±3.932 vs 32.639±3.510; P&lt;0/05). None of the echo parameters were different between normotensive subjects with different circadian BP pattern. Trans tricuspid valve early diastolic (E) and late diastolic (A) peak velocities were significantly lower in hypertensive patients (1.416±0.130 vs 0.897±1.49; P&lt;0.005). Hence, non-dipper hypertensives had significantly lower tricuspid E/A ratio in comparison with dippers (0.812±0.094 vs 1.048±0.101; P&lt;0.00001). Interventricular septum and posterior wall diameters were higher in non-dipper hypertensives (1.134±0.131 vs. 1.322±0.138; P&lt;0.00001 and 1.072±0.175 vs. 1.254±0.135; P&lt;0.001; respectively). Conclusion: Study data show increased interdependence between two ventricles. Patients with arterial hypertension have systole-diastolic dysfunction, which especially well is present in patients with non-dipper circadian BP profile.

Investigation on aeration efficiency and energy efficiency optimization in recirculating aquaculture coupling CFD with Euler-Euler and species transport model

Aeration plays a crucial role in maintaining the overall health and sustainability of the recirculating aquaculture system. Conventional aeration operates continuous and consumes 35.06 % of equipment energy consumption. How to optimize aeration while ensuring normal fish growth remains a great challenge. To address these challenges, this research paper established a coupled model of computational fluid dynamics and species transport model (CFD-STM). Aeration tests were carried out in a 33.3 m3 culture tank using a 0.31 m diameter aerator to find out the impacts of operating variables (aeration flow rate, bubble diameter, inlet velocity, and aerator position) on oxygen transfer using a microporous aeration system. A CFD-STM model was coupled to obtain the optimum values of aeration parameters. Results revealed that the Standard Aeration Efficiency (SAE) reductions by 32.1 % for 50 % larger aeration flow rate and 86.4 % for 50 % larger bubble diameter, as well as SAE achieved 5.67 kg/kWh with an aerator position scale factor equal to 0.48. In addition, the energy consumption of the Roots blower was compared for a single aeration and dissolved oxygen saturation. Results indicated that smaller bubbles microbubbles can effectively improve oxygen transfer coefficient. The energy consumption was reduced by 15.7 % for 50 % larger aeration flow rate and 38.6 % for 50 % lower bubble diameter. Based on the results, this study demonstrated that CFD is a useful tool to optimize the aeration system design and operation in order to enhance aeration efficiency. It provides a theoretical foundation the future optimization of energy conservation through intermittent aeration practices.

Influence of strut angle and radius on the energy absorption and failure mechanisms in 3-strut, 4-strut and 6-strut lattice structures

Abstract 3D-printed truss structures have remarkable potential in the aerospace and weight-critical technologies fields. However, design parameters need to be carefully considered. A low overhang angle or diameter can result in discrepancies. This research presents an approach by examining the effect of strut overhang angle and radius on the mechanical properties of 3-, 4- and 6-strut lattice structures under compressive loading. 1.6- and 2.4-mm diameter struts were designed with 45°, 50°, 55° and 60° overhang angle strut lattices. Experiments were simulated and compared with test results for each parameter. Even if joint regions have little effect on specimens’ density, it has a remarkable effect on mechanical properties of the specimen. To simulate this, many studies were investigated to simulate joint regions. The study’s goal is to deepen the understanding of how design variations in strut lattice structures influence their energy-absorbing characteristic and mechanical behavior, using a combination of static tests and finite element analysis for validation. This insight is crucial for optimizing lattice design to balance weight, strength, and energy-absorbing capacity effectively. The experimental test result and numerical result showed rather good agreement. It is observed that joint regions, overhang angle, and diameters were the main parameters affecting specimens’ mechanical behavior.

Predictive value of NCCT quantitative analysis for proximal and middle impacted ureteral stones.

The purpose of the study was to explore the predictive value of preoperative quantitative NCCT analysis for proximal and middle ureteral stone impaction. Data of 128 patients who diagnosed with proximal and middle ureteral stones were analyzed. Stone size, upper diameter of the ureter(D1), lower diameter of the ureter (D2), CT attenuation of the ureter above the stone (HA, 'HU above'), CT attenuation of the ureter below the stone (HB, 'HU below'), CT attenuation values of the stone's proximal segments (C1), CT attenuation values of the stone's distal segments (C2), and ureteral wall thickness(UWT)were recorded. Logistic regression was used to perform univariate and multivariate analyses of the data to determine the independent predictors of proximal and middle ureteral stone impaction. The receiver operating characteristic (ROC) curve was plotted to evaluate the predictive performance. Among the 128 patients, 52 (40.6%) had impacted stones, while 76 (59.4%) did not. Multivariate logistic regression analysis showed that stone size > 9.45mm (OR = 1.372, 95% CI = 1.071-1.756, P = 0.012), UWT > 3.22mm (OR = 4.217, 95% CI = 2.165 ~ 8.213, P < 0.001)、DDR > 2.10 (OR = 4.901, 95% CI = 1.797 ~ 13.365, P = 0.002)and HBA > 1.58 (OR = 5.237,95% CI = 1.502 ~ 18.259, P = 0.009)were independent risk factors for predicting ureteral stone impaction. In conclusion, stone size, UWT, DDR, and HBA show crucial predictive value for impaction of stones.