Changes In Flow Research Articles

Cerebral Endoscopy in Hydrocephalus Secondary to Neurocysticercosis

Neurocysticercosis (NCC) is a common parasite affecting the central nervous system, causing over 50,000 fatalities annually in Latin America. Treatment varies depending on the location and prognosis is not good. Treatment often involves anti-parasitic medications and shunt implantation. Meningitis, stroke, and hydrocephalus are common complications. Endoscopy is the primary treatment for ventricular forms, but alternative methods like shunt implantation and microsurgery are considered. Anti-cysticercus medications and shunt implantation are recommended for patients with subarachnoid forms and hydrocephalus. Endoscopy is a potential treatment for extra-parenchymal NCC due to its potential to reduce inflammation and improve cerebrospinal fluid (CSF) circulation. However, early extraction may reduce the risk of chronic inflammation. Patients without extracorporeal membranes (ETV) have a higher shunt failure rate, potentially due to tolerance to changes in CSF flow. The Karnofsky index, an estimate used to evaluate functional status, suggests that endoscopy as an initial therapy is a viable option. Patients with a history of shunting or chronic illness may benefit from a comprehensive examination of the ventricular system and basal subarachnoid space. Steroid administration is recommended after treatment to prevent parasitic antigen release and immune response.

Changes in cerebral hemodynamics after week 32 of gestation in fetuses with late-onset fetal growth restriction

BACKGROUND: Late-onset fetal growth restriction is characterized by changes in fetal cerebral hemodynamic patterns. Blood flow parameters in the anterior, middle, and posterior cerebral arteries have been studied previously, and there was shown a relationship between changes in certain cerebral artery vascular resistance parameters and increased risk of adverse perinatal outcomes such as fetal hypoxia in labor, cesarean section, and stillbirth. AIM: The aim of this study was to search for cerebral hemodynamic patterns in fetuses with late-onset fetal growth restriction after week 32 of gestation. MATERIALS AND METHODS: This prospective study included 110 pregnant women at week 32 or more of gestation who underwent fetal ultrasound (fetometry and Doppler with additional measurement of vascular resistance parameters in the anterior and posterior cerebral arteries). Ultrasound findings were assessed for the presence of late-onset fetal growth restriction. The systole-diastolic ratio, resistance index, and pulsatility index were evaluated in appropriate-for-gestational-age fetuses and in fetuses with late-onset fetal growth restriction. RESULTS: A total of 128 middle, 86 anterior, and 87 posterior cerebral arteries measurements were included in the calculations. From weeks 32–33 to preterm gestation in appropriate-for-gestational-age fetuses, a decrease in the middle cerebral artery parameters was observed, while in the anterior and posterior cerebral arteries, the vascular resistance parameters remained at the same level or slightly increased. A nonlinear trend of blood flow changes in the anterior and posterior cerebral arteries was observed in fetuses with fetal growth restriction — the values increased by weeks 34–36 of gestation and decreased in preterm gestation. At the same time, differences (р 0.05) were found between the median values of the systolic-diastolic ratio, resistance index and pulsatility index in the anterior and posterior cerebral arteries at weeks 34–36 and those at preterm gestation. CONCLUSIONS: Changes in fetal cerebral hemodynamics in fetal growth restriction, in particular, a shift in the peak values of vascular resistance parameters to later gestational periods may be associated with changes in the development of integrative functions of the central nervous system and neurovascular development of the fetal brain (cortex), which occurs predominantly in the third trimester of pregnancy.

Structural, blood flow and functional changes in the macular area and the expression of aqueous humor factors in myopia

ObjectiveTo compare the macular area parameters and aqueous humor factors between myopia and emmetropia.MethodsConvenience sampling was used to select patients who visited the Changzhi Aier Eye Hospital’s department of ophthalmology from December 2018 to December 2022 as the study participants. They were divided into three groups according to whether they were diagnosed as mild myopia myopic, highly myopic or not as follows: the mild myopia group (60 cases, 108 eyes), the high myopia group (46 cases, 78 eyes) and the healthy emmetropia group (40 cases, 65 eyes). The differences in the macular integrity (MI) assessment, optical coherence tomography and optical coherence tomography angiography parameters and aqueous humor factors were compared between the three groups.ResultsAL in high myopia group was the highest, and that in emmetropia group was the lowest. The BCVA of mild myopia group was the highest. The RS in the high myopia group were significantly lowest in the three groups (26.42 ± 1.04 vs. 28.34 ± 0.76 vs. 31.92 ± 0.77) (F = 5.374, p = 0.013). The 63% BCEA, 95% BCEA and MI in the high myopia group were significantly highest (p < 0.05). The mean RPE thickness, mean CT and mean RT in the high myopia group were lowest (p < 0.05). The blood flow density were lowest in the superficial fovea, paracentral fovea and different subdivisions of the paracentral fovea in the high myopia group (p < 0.05). The VEGF concentration in the aqueous humor of the high myopia group was lowest (25.62 ± 17.43 vs. 32.45 ± 24.67 vs. 64.37 ± 21.14) (F = 9.237, p < 0.001). The MMP-2 concentration was highest (483 ± 201.48 vs. 410 ± 142.37 vs. 386 ± 154.34) (F = 5.542, p = 0.018). The VEGF concentration in the aqueous humor factor was negatively correlated with the AL in the myopia group (r = −0.438, p = 0.002), the MMP-2 concentration was positively correlated with the AL (r = 0.484, p = 0.010).ConclusionPatients with high myopia showed decreased retinal light sensitivity, fixation stability, superficial blood flow density and retinal thickness compared with people with emmetropia. A decreased VEGF concentration and increased MMP-2 concentration in the aqueous humor factor have potential associations with the development of high myopia.

Black swans swimming in product streams: method for including unplanned events in life cycle assessment

Abstract Introduction Unplanned events such as accidents and more massive black-swan events are contingent to modern technology. However, varying approaches and inconsistent guidelines make the inclusion of unplanned events in life cycle assessment (LCA) uncommon and challenging. This paper discusses the relevance of considering unplanned events in LCA and shows how they can be included in LCA practice. Method A theoretical background to the concepts of black swans, accidents, and unplanned events is first provided. We then propose a method for how unplanned events can be included in LCA practice, illustrated through three cases: (i) a sabotage in the energy system, (ii) an accident in the use phase, and (iii) a sudden policy change. Results The results show that unplanned events can be included and may significantly affect LCA results, sometimes even fulfilling criteria for black-swan events. Conclusions We suggest that unplanned events should be included in LCA when relevant, e.g. as one scenario in LCAs of product systems sensitive to accidents. We also suggest that changes in flows due to unplanned events should be considered in unit processes, so that their impacts become distributed across downstream product systems depending on demand for the unit-process output.

Investigation of [11C]carfentanil for mu opioid receptor quantification in the rat brain

[11C]Carfentanil ([11C]CFN) is the only selective carbon-11 labeled radiotracer currently available for positron emission tomography (PET) imaging of mu opioid receptors (MORs). Though used extensively in clinical research, [11C]CFN has not been thoroughly characterized as a tool for preclinical PET imaging. As we were occasionally observing severe vital sign instability in rat [11C]CFN studies, we set out to investigate physiological effects of CFN mass and to explore its influence on MOR quantification. In anesthetized rats (n = 15), significant dose-dependent PCO2 increases and heart rate decreases were observed at a conventional tracer dose range (IV, > 100 ng/kg). Next, we conducted baseline and retest [11C]CFN PET scans over a wide range of molar activities. Baseline [11C]CFN PET studies (n = 27) found that nondisplaceable binding potential (BPND) in the thalamus was positively correlated to CFN injected mass, demonstrating increase of MOR availability at higher injected CFN mass. Consistently, when CFN injected mass was constrained < 40 ng/kg (~ 10% MOR occupancy in rats), baseline MOR availability was significantly decreased. For test–retest variability (TRTV), better reproducibility was achieved by controlling CFN injected mass to limit the difference between scans. Taken together, we report significant cardiorespiratory depression and a paradoxical influence on baseline MOR availability at conventional tracer doses in rats. Our findings might reflect changes in cerebral blood flow, changes in receptor affinity, or receptor internalization, and merits further mechanistic investigation. In conclusion, rat [11C]CFN PET requires stringent quality assurance of radiotracer synthesis and mass injected to avoid pharmacological effects and limit potential influences on MOR quantification and reproducibility.

Neuromuscular electrical stimulation for facial wrinkles and sagging: The 8-week prospective, split-face, controlled trial in Asians.

This study aims to fill the knowledge gap regarding the effects of high frequency facial neuromuscular electrical stimulation (fNMES) on facial aging, using a device equipped with CERTEC (Cell Energy Regeneration Technology) operating between 40 and 190 kHz. This prospective split-face study was conducted at Tokyo University Hospital between March and May 2023 with 24 healthy adult women aged 30-59. The intervention group used the fNMES device along with basic skin care on one side of the face, and basic skin care alone on the other side for 8 weeks. Evaluations included changes in skin wrinkles, sagging, and blood flow. This study found significant improvements in skin elasticity and degree of wrinkles in the areas intervened with fNMES (p < 0.05, respectively). In addition, the intervention resulted in significant improvements in jawline angle (p < 0.01), submental volume (p < 0.05), cheek volume (p < 0.05), maximum nasolabial fold depth (p = 0.03), and total volume of the nasolabial folds (p = 0.03). The fNMES intervention also showed improvement in blood flow (p < 0.05). These improvements were also subjectively assessed by the participants in subject questionnaires at 8 weeks after the intervention (p < 0.05). This study suggests that high frequency fNMES effectively improves facial skin elasticity, reduces wrinkles and sagging, promotes blood flow, and contributes to overall facial appearance rejuvenation. Although further studies are needed, high frequency fNMES appeared promising as a noninvasive anti-aging therapy.

Constructing a Transient Ischemia Attack Model Utilizing Flexible Spatial Targeting Photothrombosis with Real-Time Blood Flow Imaging Feedback

Transient ischemic attack (TIA) is an early warning sign of stroke and death, necessitating suitable animal models due to the associated clinical diagnostic challenges. In this study, we developed a TIA model using flexible spatially targeted photothrombosis combined with real-time blood flow imaging feedback. By modulating the excitation light using wavefront technology, we precisely created a square light spot (50 × 250 µm), targeted at the distal middle cerebral artery (dMCA). The use of laser speckle contrast imaging (LSCI) provided real-time feedback on the ischemia, while the excitation light was ceased upon reaching complete occlusion. Our results demonstrated that the photothrombus formed in the dMCA and spontaneously recanalized within 10 min (416.8 ± 96.4 s), with no sensorimotor deficits or infarction 24 h post-TIA. During the acute phase, ischemic spreading depression occurred in the ipsilateral dorsal cortex, leading to more severe ischemia and collateral circulation establishment synchronized with the onset of dMCA narrowing. Post-reperfusion, the thrombi were primarily in the sensorimotor and visual cortex, disappearing within 24 h. The blood flow changes in the dMCA were more indicative of cortical ischemic conditions than diameter changes. Our method successfully establishes a photochemical TIA model based on the dMCA, allowing for the dynamic observation and control of thrombus formation and recanalization and enabling real-time monitoring of the impacts on cerebral blood flow during the acute phase of TIA.

Urban exodus or suburbanisation? Medium-term COVID-19 pandemic impacts on internal migration in Japan

The COVID-19 pandemic has profoundly affected internal migration patterns worldwide. Most previous studies have reported on pandemic-induced changes in internal migration using data from 2020 and 2021. Therefore, little is known about the pandemic’s medium-term impact. To address this gap, this study investigated an annual series of migration patterns from 2019 to 2023 in Japan. At the municipal level, relationships between net migration rates and population density indicated that the urbanisation trend became weak in 2020, compared to that in 2019, and it was the weakest in 2021. The urbanisation degree became stronger in 2023, increasing to the level in 2020. Using annual inter-municipal migration flows, this study then investigated changes in migration flows to/from and within three major metropolitan areas (Tokyo, Nagoya, and Osaka). The changes in sizes of these flows and migration effectiveness index suggested that the pandemic had the largest impact in the Tokyo metropolitan area, among the three areas, and it stimulated intra-metropolitan migration as suburbanisation, rather than net out-migration as ‘urban exodus’, in Japan. The overall results indicated that the pandemic had the largest impact in 2021, which got smaller as the migration patterns recovered to the pre-pandemic ones in 2023.

Urban exodus or suburbanisation? Medium-term COVID-19 pandemic impacts on internal migration in Japan

The COVID-19 pandemic has profoundly affected internal migration patterns worldwide. Most previous studies have reported on pandemic-induced changes in internal migration using data from 2020 and 2021. Therefore, little is known about the pandemic’s medium-term impact. To address this gap, this study investigated an annual series of migration patterns from 2019 to 2023 in Japan. At the municipal level, relationships between net migration rates and population density indicated that the urbanisation trend became weak in 2020, compared to that in 2019, and it was the weakest in 2021. The urbanisation degree became stronger in 2023, increasing to the level in 2020. Using annual inter-municipal migration flows, this study then investigated changes in migration flows to/from and within three major metropolitan areas (Tokyo, Nagoya, and Osaka). The changes in sizes of these flows and migration effectiveness index suggested that the pandemic had the largest impact in the Tokyo metropolitan area, among the three areas, and it stimulated intra-metropolitan migration as suburbanisation, rather than net out-migration as ‘urban exodus’, in Japan. The overall results indicated that the pandemic had the largest impact in 2021, which got smaller as the migration patterns recovered to the pre-pandemic ones in 2023.

Numerical investigation of slip effects on heat and mass transfer in a vertical channel with immiscible micropolar and viscous fluids of variable viscosity

AbstractThis study investigates the fluid flow, heat, and mass transfer phenomena within a vertical channel containing two immiscible fluids, with a particular focus on slip effects. These effects include no slip, velocity slip, thermal slip, and multiple slips, each analyzed with appropriate boundary conditions. The study thoroughly examines key characteristics, such as variations in thermal conductivity and viscosity. Using a sixth‐order Runge–Kutta numerical method implemented using Mathematica, the study achieves precise solutions for complex scenarios. The detailed results show how the various slip mechanisms and relevant parameters interact with each other in complex ways. These findings are useful for both theoretical understanding and application in real‐life engineering situations. This study also gives important information about how fluid flow, heat transfer, and mass transfer change under different slip effects. It looks at these effects and shows how they change visually. It also carefully calculates and analyzes engineering parameters like the Nusselt number, shear stress, and Sherwood number using bar charts, showing how they affect and behave. The study resulted in velocity slip having a minimal impact on temperature, whereas thermal slip resulted in higher temperatures. Both velocity and thermal slip conditions simultaneously result in the lowest temperatures.

Numerical investigation of slip effects on heat and mass transfer in a vertical channel with immiscible micropolar and viscous fluids of variable viscosity

AbstractThis study investigates the fluid flow, heat, and mass transfer phenomena within a vertical channel containing two immiscible fluids, with a particular focus on slip effects. These effects include no slip, velocity slip, thermal slip, and multiple slips, each analyzed with appropriate boundary conditions. The study thoroughly examines key characteristics, such as variations in thermal conductivity and viscosity. Using a sixth‐order Runge–Kutta numerical method implemented using Mathematica, the study achieves precise solutions for complex scenarios. The detailed results show how the various slip mechanisms and relevant parameters interact with each other in complex ways. These findings are useful for both theoretical understanding and application in real‐life engineering situations. This study also gives important information about how fluid flow, heat transfer, and mass transfer change under different slip effects. It looks at these effects and shows how they change visually. It also carefully calculates and analyzes engineering parameters like the Nusselt number, shear stress, and Sherwood number using bar charts, showing how they affect and behave. The study resulted in velocity slip having a minimal impact on temperature, whereas thermal slip resulted in higher temperatures. Both velocity and thermal slip conditions simultaneously result in the lowest temperatures.

Dynamic Interferometry With Retrace Error Correction Using Fringe Projection For High-Gradient Fields

This paper introduces an innovative approach aimed at advancing the characterization of high-gradient flow fields through the integration of dynamic interferometry and fringe projection techniques. Traditional interferometry offers a precise tool sensitive to optical path changes, typically used to measure refractive index variations induced by factors such as density changes in fluid flow. Rays are usually considered as straight lines, and refraction can be neglected. However, in scenarios involving high-gradient fields, such as supersonic flow with shock waves, optical path changes due to ray bending become significant. In these high-gradient fields, the trajectory of the ray is altered, leading to longer optical paths (resulting in incorrect values) and geometric distortions of the image (resulting in inaccuracies in position). Although retrace error corrections using numerical models of refractive index distribution can mitigate some effects, complete compensation is often challenging. To address this, our proposed technique integrates fringe projection, which is highly sensitive to ray deflections caused by variations in the index of refraction within a transparent medium. The method involves projecting a precisely defined multiplexed cosine fringe pattern across the measured area. Modifications in the pattern indicate ray bending, providing data for interferometric corrections. Real-time interferometry is seamlessly combined with the fringe projection technique to compensate for optical path length changes and mitigate mapping errors induced by ray deflections. The dynamic nature of this combined approach enables the instantaneous capture of both interferometric and fringe-projection data, making it a suitable tool for real-time measurements. Experimental verification of the technique demonstrates its efficacy, with a comparative study against traditional interferometry showcasing a significant reduction in mapping errors.

A 2D numerical model for simulating landslide dam failure and induced morphological changes considering multi-layer and non-uniform sediments

ABSTRACT Landslide dams are formed by the blockage of rivers with landslides, or any debris flows. Such dams are prone to failure and therefore, simulation of their failure and induced morphological changes is of great importance for hazard mitigation. Multi-layer and non-uniform sediments are usually observed in landslide dam materials, but these are rarely considered in simulations. In this paper, a two-dimensional numerical model considering multi-layered and non-uniform sediments is proposed. The model solves the shallow water equations, the Exner equation considering the different size fractions and Hirano's active layer equation based on a finite volume scheme in a weakly coupled approach. Two experimental tests are used to assess the applicability and accuracy of the model. The results show that it can well simulate the flow and morphological changes, as well as the surface coarsening and fining phenomena related to multi-layer and non-uniform sediments. The numerical results of dam failure process and morphological changes are in overall good agreement with the experiments, but the peak discharge and bed elevation tend to be underestimated when finer material is considered. Finally, the influence of sediments fractions and active layer depth on numerical results, as well as the limitations of the model are discussed.

Effects of sodium-glucose transporter-2 inhibition on systemic hemodynamics, renal function, and intra-renal oxygenation in sepsis-associated acute kidney injury.

People with type 2 diabetes mellitus treated with sodium-glucose transporter-2 inhibitors (SGLT2i) have lower rates of acute kidney injury (AKI). Sepsis is responsible for the majority of AKI in critically ill patients. This study investigated whether SGLT2i is renoprotective in an ovine model of Gram-negative septic AKI. Sixteen healthy merino ewes were surgically instrumented to enable measurement of mean arterial pressure, cardiac output, renal blood flow, renal cortical and medullary perfusion, and oxygenation. After a 5-day recovery period, sepsis was induced via slow and continuous intravenous infusion of live Escherichia coli. Twenty-three hours later, sheep were randomized to receive an intravenous bolus of 0.2 mg/kg empagliflozin (n = 8) or a fluid-matched vehicle (n = 8). Empagliflozin treatment did not significantly reduce renal medullary hypoperfusion or hypoxia, improve kidney function, or induce histological changes. Renal cortical oxygenation during the intervention period was 47.6 ± 5.9mmHg in the empagliflozin group compared with 40.6 ± 8.2mmHg in the placebo group (P = 0.16). Renal medullary oxygenation was 28.0 ± 18.5mmHg in the empagliflozin compared with 25.7 ± 16.3mmHg (P = 0.82). Empagliflozin treatment did not result in significant between-group differences in renal blood flow, kidney function, or renal histopathological changes. In a large mammalian model of septic AKI, a single dose of empagliflozin did not improve renal microcirculatory perfusion, oxygenation, kidney function, or histopathology.

Network power and exclusion of informal waste pickers when plastic flows change: A case study of community waste banks in Klaten Municipality in Indonesia

Countries, like Indonesia, without advanced waste management systems and with higher levels of population and consumption growth, face particular challenges in addressing plastic waste and marine pollution. To address and prevent plastic marine pollution, Indonesia introduced mitigation initiatives, such as Extended Producer Responsibility, waste banks, and take back schemes. While recent research shows such approaches are able to prevent marine litter, research into their social and equity effects is scarce. This is problematic, because mitigation initiatives can have in- and exclusion effects in terms of access to valuable waste for vulnerable, informal waste actors. This article combines the sociology of network and flows with a network power typology to study how the implementation of waste banks in Klaten Municipality, Indonesia not only led to reduction in plastic pollution, but also the exclusion of cartmen, waste pickers and mobile intermediates from waste networks and thus from accessing these valuable waste flows. A waste bank is a community based business that provides households with additional income and turns household waste into economically valuable materials by trading them with recyclers. In doing so they outcompete a vulnerable group like waste pickers. Instead of waste pickers, households become part of the plastic waste networks. In addition to assessing environmental effects of (marine) plastic pollution mitigation initiatives, more scholarly attention should go towards assessing the in- and exclusion dynamics around different plastic mitigation initiatives. The sociology of network and flows is a useful lens through which to examine these in- an exclusion effects.

Southwest Pacific Ocean Warming Driven by Circulation Changes

AbstractAn area of ocean centered on 179°E, 46°S has warmed to full depth since 2006, with surface warming around 5 times the global rate. This Subtropical Front area is associated with a confluence of warm, salty, subtropical water from the north carried in a western boundary current and cold, fresh, subantarctic water from the south carried in the northernmost branch of the Antarctic Circumpolar Current. Temperature and salinity changes observed from Argo floats indicate that the Subtropical Frontal Zone has moved west ∼120 km, creating this area of strong warming analogous to changes in extension regions of other western boundary currents. The warming is a result of changes in the local flows of subantarctic water, evident in satellite altimeter data and 1,000 m Argo trajectories, which in turn likely result from changes in meridional ocean heat content and winds. The warming has placed this biologically‐significant region in almost perpetual marine heatwave conditions.

Engaging Mood Brain Circuits with Psilocybin (EMBRACE): a study protocol for a randomized, placebo-controlled and delayed-start, neuroimaging trial in depression

BackgroundMajor depressive disorder (MDD) is a leading cause of disability worldwide across domains of health and cognition, affecting overall quality of life. Approximately one third of individuals with depression do not fully respond to treatments (e.g., conventional antidepressants, psychotherapy) and alternative strategies are needed. Recent early phase trials suggest psilocybin may be a safe and efficacious intervention with rapid-acting antidepressant properties. Psilocybin is thought to exert therapeutic benefits by altering brain network connectivity and inducing neuroplastic changes that endure for weeks post-treatment. Although early clinical results are encouraging, psilocybin’s acute neurobiological effects on neuroplasticity have not been fully investigated. We aim to examine for the first time how psilocybin acutely (intraday) and subacutely (weeks) alters functional brain networks implicated in depression.MethodsFifty participants diagnosed with MDD or persistent depressive disorder (PDD) will be recruited from a tertiary mood disorders clinic and undergo 1:1 randomization into either an experimental or control arm. Participants will be given either 25 mg psilocybin or 25 mg microcrystalline cellulose (MCC) placebo for the first treatment. Three weeks later, those in the control arm will transition to receiving 25 mg psilocybin. We will investigate whether treatments are associated with changes in arterial spin labelling and blood oxygenation level-dependent contrast neuroimaging assessments at acute and subacute timepoints. Primary outcomes include testing whether psilocybin demonstrates acute changes in (1) cerebral blood flow and (2) functional brain activity in networks associated with mood regulation and depression when compared to placebo, along with changes in MADRS score over time compared to placebo. Secondary outcomes include changes across complementary clinical psychiatric, cognitive, and functional scales from baseline to final follow-up. Serum peripheral neurotrophic and inflammatory biomarkers will be collected at baseline and follow-up to examine relationships with clinical response, and neuroimaging measures.DiscussionThis study will investigate the acute and additive subacute neuroplastic effects of psilocybin on brain networks affected by depression using advanced serial neuroimaging methods. Results will improve our understanding of psilocybin’s antidepressant mechanisms versus placebo response and whether biological measures of brain function can provide early predictors of treatment response.Trial registrationClinicalTrials.gov Identifier: NCT06072898. Registered on 6 October 2023.

Predicting and Measuring Fluid Responsiveness by Hemodynamic Indices versus Transthoracic Echocardiography in Clinically Shocked Patients

Abstract Background In the last decades dynamic measures had evolved as a better solution to predict fluid responsiveness in clinically shocked patients, out of multiple dynamic parameters we chose transthoracic echocardiographic based measurements of variations of aortic blood flow and inferior vena caval diameter. Aim of the Work to assess accuracy of transthoracic echo measured variation in aortic blood flow and inferior vena caval diameter with limited bolus crystalloid infusion in predicting fluid responsiveness in patients with clinical shock. Patients and Methods This study included 51 selected Patients with acute circulatory failure secondary to clinical shock admitted to ICU. All patients had undergone basic transthoracic echocardiographic (TTE) assessment of aortic blood flow (using left ventricular outflow tract velocity time integral as a surrogate) and inferior vena caval diameter changes with respiratory cycle, these measures were obtained at time of diagnosis of shock and repeated after infusion of 300 ml crystalloid fluid bolus (over fifteen minutes). Results Our results had revealed significant difference between responders and non-responders regarding aortic flow variation after fifteen minutes. Conclusion Based on the results obtained in this study, it was proved that transthoracic echocardiography can be used as an accurate method to predict fluid responsiveness in shocked patient with fluid challenge.

Study on dynamic mechanism of granular flow erosion and entrainment based on DEM theory

BackgroundGranular flows are common on the Qinghai–Tibet Plateau and the Hengduan Mountains in China, and their dynamic process processes have obvious erosional and entrainment effects. On the one hand, the volume of the granular flow increases by a factor of several or ten, which significantly increases its ability to cause a catastrophe; on the other hand, the eroded loose material affects the granular flow dynamics process and changes its state of motion.MethodsIn this paper, the dynamic mechanism of granular flow erosion and entrainment is investigated by DEM simulation.Purpose The effects of different substrate materials and substrate boundary conditions on granular flow erosion and entrainment are analyzed, and the effects of material mixing caused by erosion and entrainment on the state of motion of granular flow are discussed. It was verified that the kinetic mechanisms of granular flow erosion and entrainment includes impact erosion, ploughing, and shear abrasion.ResultsAnd discovered that small matrix particle size, small matrix boundary friction, and small matrix thickness lead to stronger ploughing and shear abrasion; Large matrix fractal dimensions result in stronger ploughing and weaker shear abrasion, and the granular flow does not entrain large amounts of material to the accumulation zone. Meanwhile, the dynamics of erosion and entrainment of granular flow were investigated, and the results showed that: 1. The greater the erosion rate, the greater the velocity and kinetic energy of the granular flow, the greater the distance traveled, and the smaller the apparent friction angle (i.e., the greater the mobility). 2. The amount of small granules in a granular flow changes its fluidity, the more small granules there are, the more fluid it is. 3. The fit reveals that the substrate fractal dimension has the strongest effect on the velocity and kinetic energy of granular flow, followed by substrate thickness and substrate boundary friction.

Short-term effects of antenatal betamethasone on fetal cardiovascular and circulation status: A quasi-experimental observational (before-after) study

Background: The administration of antenatal corticosteroid is a standard treatment to reduce the rate of perinatal mortality and morbidity; however, there is limited evidence regarding the potential effects of betamethasone on the constriction of the ductus arteriosus (DA). Objective: This study aimed to investigate the short-term effects of antenatal betamethasone on fetal cardiovascular and circulation status. Materials and Methods: This quasi-experimental observational (before-after) study was conducted on 32 singleton fetuses. The participants were healthy pregnant women with a diagnosis of placenta accreta spectrum who were eligible for 2 doses of betamethasone and referred to prenatal care clinic, Vali-E-Asr hospital; Tehran, Iran from January 2021-May 2022. The results of fetal echocardiography and Doppler sonography were compared before and after the administration of antenatal corticosteroid therapy. Results: Following betamethasone injection, significant increases were observed in peak systolic and diastolic velocity of the DA without constriction of the DA (p &lt; 0.001, p = 0.002 respectively). However, no significant changes were observed in right ventricular function, tricuspid valve function, Doppler of ductus venous, and peak systolic velocity of the aortic isthmus (p &gt; 0.05). Doppler examination of the uterine, umbilical, and middle cerebral arteries also showed no significant changes (p &gt; 0.05). Conclusion: Considering the benefits of antenatal corticosteroid therapy, its administration seems reasonable in preterm births. The transient changes in ductal blood flow are not prohibitive. Key words: Betamethasone, Premature birth, Ultrasonography, Doppler, Echocardiography, Fetus.