Reduction In Flow Research Articles

Surgical reduction of a high-flow dialysis fistula has long-term positive effects of the heart

Abstract Introduction Part of chronic haemodialysis patients develop a high-flow arteriovenous fistula (AVF). The volume overload caused by the presence of a high-flow AVF leads to increased cardiac output, dilation of cardiac chambers, increased pulmonary artery pressure or even to the development of high-output heart failure. Our previous data showed a positive effect of AVF flow-reducing surgery in 6 weeks follow-up. Purpose The purpose of this study was to analyse the long-term effect of AVF blood flow (Qa) reduction on cardiac structure and function. Methods We included patients with high-flow AVFs (defined as Qa over 1500 mL/min) indicated for blood flow reduction surgery for heart failure symptoms or pre-defined echocardiographic changes (left ventricular hypertrophy, severe secondary valvular regurgitations, or pulmonary hypertension). Echocardiography was performed one day before the surgery, the 6 weeks, 6 months, and 12 months thereafter. Qa was measured by ultrasound during the same visits. Results 27 patients were included, 20 men and 7 women, aged 57 ± 13 years. The procedure led to an immediate decrease in Qa. However, we observed failure of the procedure within 1 year in 8 (= 30%) patients defined by increased Qa back to pre-surgery values. Detailed results are displayed in Table 1. Estimated pulmonary arterial systolic pressure and left atrial volume remained significantly lower after 1 year despite the Qa rise. Effective cardiac output (= difference of cardiac output and Qa) rose immediately and remained increased during the follow-up period despite the increase in AVF blood flow. Conclusions We observed a long-time positive effect of AVF blood flow reduction surgery on the heart despite a significant Qa rise. The effective cardiac output remained increased despite the gradual increase of Qa, probably due to the adaptation of systemic arterioles.

Apolipoprotein C3-rich low-density lipoprotein (AC3RL) exacerbates cerebral ischaemic stroke injury by increasing BBB leakage via LOX-1

Abstract Background Ischaemic stroke causes the abrupt reduction or cessation of blood flow to the brain results in a cascade of events that can compromise blood-brain barrier (BBB) integrity. We revealed that an increase in apolipoprotein C3 (ApoC3)-rich low-density lipoprotein (AC3RL) is associated with endothelial cell apoptosis and inflammatory responses, indicating that AC3RL is one of the risk factors for cardiovascular events. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) triggers a cascade of events within endothelial cells that leads to endothelial dysfunction. Purpose We aimed to investigate whether AC3RL affects BBB permeability via the LOX-1, and thus increases brain damage. Methods We collected the whole blood from normal and patients with ischaemic events and separated them by centrifugation. AC3RL were collected using FPLC. We performed middle cerebral artery occlusion (MCAO) surgery to induce ischaemic stroke using B6 (C57BL/6) and LOX-1-/- mice injected with AC3RL. Triphenyl tetrazolium chloride (TTC) and Evans blue stains were accessed to confirm brain injury and BBB permeability. Results FPLC results showed that patients with ischaemic events presented higher levels of AC3RL compared to normal people. TTC stain showed the increased area of ischaemic penumbra damage in B6 mice with AC3RL injection, and LOX-1-/- mice with AC3RL injection were significantly protected. Evans blue dye leakage was observed in the brain tissues of B6 mice with AC3RL injection. LOX-1-/- mice with AC3RL injection revealed a decrease in BBB permeability. The modified neurological severity score (mNSS) method revealed a significant rise in B6 mice with AC3RL injection, which suggested a decline in motor and nervous function. LOX-1-/- mice with AC3RL injection significantly improved in motor and neurological functioning. Conclusions We demonstrate that AC3RL, through its effects on LOX-1, is associated with an increased risk of BBB damage after stroke. Therefore, pharmacological inhibition of AC3RL-LOX-1 interaction will be the main strategy to reduce severe brain damage. Figure 1: (A) AC3RL percentage (%) in individuals. Normal: healthy people, Ischemic event: patients who have experienced an ischemic event. **p < 0.001 vs. Normal group. (B, C) TTC stain of brain tissue after euthanasia to pinpoint the site of brain damage. The white portion of the mice brains indicated the site of the injury. (D, E) Evans blue dye leakage study in mice brains exhibited BBB permeability changes. (F) Assessment of mice's motor and neurological performance using the mNSS. Data are expressed as the mean ± SEM. **p < 0.001, ****p < 0.0001 vs. sham group, ##p < 0.001 vs. B6 I.V. AC3RL group.Graphical abstractFigure 1.

Gender differences in coronary artery disease patterns

Abstract Background Gender differences in clinical presentation, natural history, and prognosis of coronary artery disease (CAD) have been reported. Fractional flow reserve (FFR) has also been shown to yield higher values in women than men. However, the gender differences in CAD patterns (focal vs diffuse) defined by coronary physiology remain to be studied. Methods This prospective study was performed at 23 sites and enrolled patients with at least one epicardial lesion with an FFR ≤ 0.80 intended to be treated by PCI. All patients underwent a standardized physiological protocol that mandated FFR pullbacks with pullback pressure gradient (PPG) calculation. The aim was to compare CAD patterns, defined by PPG, between genders. Results Overall, 1004 patients were included in the analysis, 236 females (250 vessels) and 768 males (794 vessels). Women were older (69.8 ± 10.3 vs. 67.0 ± 10.1, p <0.001), less frequently smokers (9.7% vs. 18.6%, p = 0.002), had less prior PCI in a non-target vessel (19.1% vs. 30.6%, p = 0.001) and had less prior MIs (14.4% vs. 21.5%, p = 0.021). On the baseline seven-item Seattle Angina Questionnaire (SAQ-7), females reported more physical limitation (70.9 ± 29.5 vs. 80.9 ± 25.1, p < 0.001), more frequent angina (76.7 ± 22.9 vs. 81.5 ± 20.3, p = 0.002) and a lower quality of life (51.8 ± 29.4 vs. 57.8 ± 29.1, p = 0.006) than men for the same degree of flow reduction (FFR 0.69 ± 0.12 vs. 0.67 ± 0.11, p=0.098). In women, the pattern of CAD demonstrated a more focal nature compared to men (PPG 0.65 ± 0.16 vs. 0.61 ± 0.16, p = 0.001). Also, women achieved higher post-PCI FFR (0.88 ± 0.07 vs. 0.87 ± 0.07, p = 0.02). The rate of periprocedural MI was not statistically different between genders (5.1% vs. 5.8%, p = 0.79) Conclusion Among patients with hemodynamically significant CAD, women report more symptoms and lower quality of life. Despite sharing a similar degree of flow impairment, women exhibited a more focal CAD phenotype than men, leading to superior physiological outcomes after PCI.Study flowchartPRO and Phisiology by gender

Research on the distribution of debris flow impact on the upstream surface of the check dam

The impact force of debris flow is not only an important indicator of the risk assessment of debris flow and the strength impact resistance of buildings against debris flow, but also an important parameter in the design of various debris flow prevention projects (such as the check dam and the drainage channel, etc.). The pressure sensors are arranged at different positions (monitoring points) on the upstream face of the check dam. By changing the slope of the drainage channel, the bulk density of debris flow and the slope gradient of the upstream face of the check dam, the time history curves of the impact force at the monitoring points under different experiment conditions are obtained. The characteristic value of the impact force of debris flow acting on the surface of the sand retaining dam is analyzed, and the evolution law of mean value and maximum value of impact force of debris flow at the same detection location with the above conditions is obtained. The mean value and maximum value of debris flow impact force at different detection locations under the same working condition are analyzed to obtain the evolution law of debris flow impact force at different locations, and then the distribution trend of debris flow impact force on the upstream face of the check dam is obtained. The research results provide scientific and reasonable theoretical basis and technical support for the stability analysis of the check dam, so as to better serve the disaster prevention and reduction of debris flow, which will improve the technical level of the debris flow prevention project to a certain extent.

Development and testing of a measuring chamber for a device for express analysis of milk quality in a flow

Mechanization and robotization of dairy farms require the development of technologies for assessing the quality of manufactured products. Monitoring milk composition and milking duration in real time is especially important for prompt response to deviations in animal physiological state parameters and timely adjustment of rations when milk yields decrease. The first version of the scatterometric device for express analysis of milk quality used a glass measuring chamber with a simple round cross-section, but it did not ensure the reduction of the turbulent flow of the milk-air mixture to laminar. This study presents the development and testing of a prototype of a measuring chamber that provides deceleration and laminarization of the milk-air mixture flow. The device operates at a milking capacity of 1 to 6 l/min, flow speed from 0.2 to 1.8 m/s. In the developed measuring chamber, a special bypass is created at an angle of 45° so that it has a common slot with the main tube. In this bypass, the flow of the milk-air mixture is slowed down to reduce turbulence and the number of air bubbles that interfere with the operation of scatterometric devices. The measurement area of the device is located in the upper part of the bypass. As a result, the developed measuring chamber has an internal diameter of the main part of 15 mm, the bypass of 11 mm, and provides close to 100% filling of the branch with liquid at the moment of the milk plug passage. The developed measuring chamber allowed the new version of the express milk quality analysis device to achieve increased accuracy and stability of measurements.

The management of high flow arteriovenous fistula and possible solutions.

The development of a high flow rate arteriovenous fistula (AVF) can expose the patient to development of heart failure due to increased cardiac preload and pulmonary hypertension. AVF flow measurement (Qa) is considered a screening tool for AVF surveillance, aiming to evaluate the access dysfunction and prevent complications, like a non-maturation, suspected stenosis, high-flow AVF, and distal ischemia. In the upper arm AVF, a high Qa may develops, which can expose the patient to the risk of high-output heart failure and ischemia. Although, the exact threshold to define high-flow access is not universally accepted, AVF with a Qa of 1-1.5 L/min or cardio-pulmonary recirculation (Qa/CO) >20% are considered at risk. In our work we describe the treatment performed in three patients with high flow AVF treated with DRIL technique with interposition of a Prosthetic Patch, revascularization procedures such as distal inflow revision or RUDI and with innovative technique a "tench snout," removal the previous anastomosis and reconstruction of the integrity of the radial artery at the terminal in pre and post anastomosis. A PTFE prosthetic segment measuring 5 cm in length and 5 mm in diameter was interposed, terminally anastomosed with the efferent cephalic vein and terminally lateral with the radial artery, reducing the anastomosis to approximately 4 mm. All treated patients showed a clear improvement in the clinical picture in particularly heart failure. The calculation of the post-intervention flow rate approximately 1500 mL/min. The patient on hemodialysis with arteriovenous fistula must be constantly monitored with clinical examination, monitoring during the hemodialysis session and color Doppler ultrasound of the AVF with calculation of the flow rate. The surgical technique used for flow reduction is chosen on the surgical experience of each operator with the main objective of preserving the autologous AVF.

Sustainable drag reduction in Taylor-Couette flow using riblet superhydrophobic surfaces

Superhydrophobic surfaces (SHSs) have been proven effective in reducing frictional drag force in various flow conditions. However, at high flow speeds, the air plastron on these surfaces collapses, leading to a decline in their effectiveness. In this study, we investigated the frictional drag forces of various SHSs and their combination with surface patterns across a wide range of flow conditions (5.00×102 < Re < 1.12×105) by using an facile coating method. Our experiments involved incorporating a superhydrophobic coating on the inner cylinder of a custom-made Taylor-Couette apparatus, integrated with a rheometer to measure torque applied on the inner rotor as a function of rotational speed. As part of our research, we calculate the effective slip length to assess the drag reduction performance of coatings, revealing an effective slip length of around 63 µm on a flat SHS. Furthermore, we explore the combined effect of superhydrophobic coatings and triangular-shaped riblets on drag reduction in Taylor-Couette flow, comparing the performance of these surfaces based on the riblet’s sharpness and the Reynolds number. Our experimental results show a reduction in measured torque of up to 24 % and 48 % on a V-grooved SHS in laminar and turbulent flow, respectively. Longevity tests confirm that the designed surfaces maintain their superhydrophobicity and drag reduction performance under turbulent flow conditions. Overall, this work introduces a passive drag reduction strategy through surface design, which substantially mitigates the frictional drag force and demonstrating considerable potential for enhanced performance and increased efficiency of Taylor-Couette systems.

Modeling the effect of land-use change on runoff water quality in the urban watershed: a case study of Settat city, Morocco

ABSTRACT The purpose of this study is to create a model of the quantity and quality of runoff from the urban watershed. The modeling was performed using a personal computer stormwater management model (PCSWMM) tool and was based on washoff and buildup for total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP) measured in the field. In addition, low impact development (LID) was used under four different scenarios to improve runoff control of the urban hydrologic cycle and reduce pollutant concentrations. Model performance was analyzed using the R2 and NSE goodness-of-fit indices. Thus, three typical rainfall events, as well as field measurement parameters (TSS, TN, and TP), were used for the model's calibration and validation. The base scenario quantified the runoff volume and pollutant load without any intervention in the runoff process control. Scenarios S2 (BR: bioretention) and S3 (PP: permeable pavement) contributed, separately, in reducing runoff and pollutant load but with relatively small percentages. In addition, the results show that scenario S4 (BR and PP) has the most significant impact on flow reduction, by about 10% compared with the base scenario, as well as on the pollutant load reduction, by about 31, 29, and 40% for the parameters TSS, TN, and TP, respectively.

Exploring the effects of moxibustion on cognitive function in rats with multiple cerebral infarctions from the perspective of glial vascular unit repairing

ObjectiveThis study aimed to explore the effect of moxibustion at Governor Vessel (GV) acupoints, including Baihui (GV 20), Shenting (GV 24) and Dazhui (GV 14) for 14 days on glial vascular unit (GVU) in rats with multiple microinfarctions (MMI), and to explore its action mechanism.MethodsThe effect and mechanism of moxibustion on vascular dementia (VD) were studied in MMI rats by means of behavioral and molecular biology experiments.ResultsRats receiving MMI showed impairment of memory function, reduction of cerebral blood flow, damage of blood-brain barrier (BBB) integrity and increased brain mass. MMI also increased neuronal degeneration in the hippocampus. Notably, levels of glial fibrillary acidic protein (GFAP) and complement component 3 significantly increased, but those of Connexin43 (CX43) and platelet derived growth factor receptor β (PDGFRβ) significantly decreased in the hippocampus of the rats receiving MMI. Moxibustion, as well as oxiracetam (ORC) treatment improved memory function and neuronal degeneration, ameliorated BBB integrity, increased cerebral blood flow and decreased brain mass. In addition, moxibustion as well as oxiracetam (ORC) treatment reduced the decrease of CX43 protein and increased PDGFRβ protein level in the hippocampus of MMI rats. Moreover, moxibustion treatment reversed MMI-induced increase of the GFAP/CX43 ratio in vascular structural units. Importantly, after PDGFRβ inhibition, VD rats treated with moxibustion had impaired learning and memory, decreased cerebral blood flow, and BBB disruption.ConclusionMoxibustion treatment at various GV acupoints improved cerebral blood flow and repaired BBB function in rats with MMI, likely through protecting GVU.

Russian-Croatian trade relations in current environment of sanctions

Aim. To assess the impact of Western European sanctions on Russian-Croatian trade relations in 2020-2023 and Croatian tourism sector.Objectives. To analyze the dynamics of key indicators of trade between the Russian Federation (RF) and Croatia under sanctions; to identify the main commodity groups in the structure of their trade; to determine the importance of Russia for the tourism sector of the Republic of Croatia.Methods. The author used such research methods as statistical analysis, generalization, description and graphical modeling.Results. The results obtained in the process of the analysis indicate a sharp decline in the volume of mutual trade of the Russian Federation with Croatia in the conditions of numerous trade restrictions from the European Union. In 2023, the commodity structure of Russian exports to the Republic of Croatia has changed significantly, the basis of Russian exports is now made up of finished goods and goods of the chemical industry. The flow of tourists from Russia occupies an insignificant share in the total tourist flow of Croatia and has little impact on the tourism sector of the Republic. Under the conditions of the sanctions regime, Croatian companies have begun to cease economic activities in the territory of the Russian Federation.Conclusions. The current situation on the world stage has determined the dynamism of mutual trade interaction between Russia and Croatia. Thus, the sanctions imposed by the countries of the collective West have a negative impact on Russian-Croatian relations both in trade and tourism. The tendencies of reduction of mutual trade and tourist flows have a long-term character and negative dynamics of interaction between the two countries. Normalization of trade relations between Russia and Croatia in the geopolitical situation today seems unlikely.

Assessing the influences of future water development projects in Tekeze-Atbara-Setit basin on the Nile River inflow at Aswan, Egypt

Study regionThe Tekeze-Atbara-Setit (TAS) basin as a portion of the Eastern Nile Basin (ENB) in Africa. Study focusENB consists of four sub-basins; one of them is the Tekeze-Atbara-Setit basin. TAS basin is subject to future water development projects, including irrigation projects and hydropower dams. Potential impacts of these projects need to be assessed regarding the inflow and hydroelectric generation at Egypt's High Aswan Dam (HAD). New hydrological insights for the regionTwo models are coupled offline; The Soil Water Assessment Tool (SWAT) model and HEC-Reservoir Simulation Model (HEC-ResSim). Base-case scenario is created without the expected future projects, in addition to five additional scenarios representing hydropower and irrigation projects. The maximum annual inflow at HAD declines by 1.6 km3 in the hydropower scenarios, while the produced power at HAD descends by 9.5 %. The maximum reduction in the annual inflow for hydropower and irrigation projects scenario at HAD is 4.63 km3 and 35.2 % for power reduction. Finally, the proposed future development project in TAS basin will have negative impacts on the flow, and generated hydropower at HAD in Egypt.

Performance analysis of ER fluid-lubricated two-lobe hole-entry hybrid journal bearings with bionic and spherical texture surfaces optimized by genetic algorithm

This study is done into the multifaceted world of ER (Electro-rheological) fluid-lubricated optimized textured hybrid hole-entry journal bearings to improve dynamic performance of the bearing and stability. These innovative techniques harness the dynamic properties of ER fluids in conjunction with optimized textured spherical and bionic textured surfaces to achieve enhanced performance and reliability. This study aims to explore the influence of ER fluid on the tribological behaviour and controllability of hybrid hole-entry journal bearings. Further it proposes the optimized design of bionic and spherical textured surfaces, capitalizing on their ability to influence fluid flow, load-carrying capacity, and friction reduction. The results demonstrate promising improvements in bearing performance metrics, including dynamic stability and fluid film damping, load-carrying capacity, friction reduction, and controllability, facilitated by the integration of ER fluid and the optimization of textured spherical and bionic textured surfaces. This study offers valuable insights into the potential applications of ER fluids and biomimicry-inspired textured surfaces in bearing system engineering. The inclusion of bionic textured hole-entry hybrid bearing lubricated with ER fluid improves the stability by up to 112.57 % and decrease the friction coefficient up to 23.37 %. The findings are expected to inform the design and development of high-performance hole-entry hybrid journal bearings with diverse industrial applications.

Acceleration is the key to drag reduction in turbulent flow

A turbulent pipe flow experiment was conducted where the surface of the pipe was oscillated azimuthally over a wide range of frequencies, amplitudes, and Reynolds numbers. The drag was reduced by as much as 35%. Past work has suggested that the drag reduction scales with the velocity amplitude of the motion, its period, and/or the Reynolds number. Here, we find that the key parameter is the acceleration, which greatly simplifies the complexity of the phenomenon. This result is shown to apply to channel flows with spanwise surface oscillation as well. This insight opens potential avenues for reducing fuel consumption by large vehicles and for reducing energy costs in large piping systems.

A lumped parameter modelling study of cerebral autoregulation in normal pressure hydrocephalus suggests the brain chooses to be ischemic

Normal pressure hydrocephalus (NPH) is associated with a reduction in cerebral blood flow and an ischemic metabolic state. Ischemia should exhaust the available autoregulation in an attempt to correct the metabolic imbalance. There is evidence of some retained autoregulation reserve in NPH. The aim of this study is to model the cerebral autoregulation in NPH to discover a solution to this apparent paradox. A lumped parameter model was developed utilizing the known limits of autoregulation in man. The model was tested by predicting the cerebral blood volume changes which would be brought about by changes in resistance. NPH and the post shunt state were then modeled using the known constraints provided from the literature. The model successfully predicted the cerebral blood volume changes brought about by altering the cerebral perfusion pressure to the limit of autoregulation. The model suggests that NPH is associated with a balanced increase in resistance within the arterial and venous outflow segments. The arterial resistance decreased after modelling shunt insertion. The model suggests that the cerebral blood flow is actively limited in NPH by arteriolar constriction. This may occur to minimize the rise in ICP by reducing the apparent CSF formation rate.

A self-regulated expiratory flow device for mechanical ventilation: a bench study

IntroductionUnregulated expiratory flow may contribute to ventilator-induced lung injury. The amount of energy dissipated into the lungs with tidal mechanical ventilation may be used to quantify potentially injurious ventilation. Previously reported devices for variable expiratory flow regulation (FLEX) require, either computer-controlled feedback, or an initial expiratory flow trigger. In this bench study we present a novel passive expiratory flow regulation device.MethodsThe device was tested using a commercially available mechanical ventilator with a range of settings (tidal volume 420 ml and 630 ml, max. inspiratory flow rate 30 L/min and 50 L/min, respiratory rate 10 min−1, positive end-expiratory pressure 5 cmH2O), and a test lung with six different combinations of compliance and resistance settings. The effectiveness of the device was evaluated for reduction in peak expiratory flow, expiratory time, mean airway pressure, and the reduction of tidal dissipated energy (measured as the area within the airway pressure–volume loop).ResultsMaximal and minimal reduction in peak expiratory flow was from 97.18 ± 0.41 L/min to 25.82 ± 0.07 L/min (p < 0.001), and from 44.11 ± 0.42 L/min to 26.30 ± 0.06 L/min, respectively. Maximal prolongation in expiratory time was recorded from 1.53 ± 0.06 s to 3.64 ± 0.21 s (p < 0.001). As a result of the extended expiration, the maximal decrease in I:E ratio was from 1:1.15 ± 0.03 to 1:2.45 ± 0.01 (p < 0.001). The greatest increase in mean airway pressure was from 10.04 ± 0.03 cmH2O to 17.33 ± 0.03 cmH2O. Dissipated energy was significantly reduced with the device under all test conditions (p < 0.001). The greatest reduction in dissipated energy was from 1.74 ± 0.00 J to 0.84 ± 0.00 J per breath. The least reduction in dissipated energy was from 0.30 ± 0.00 J to 0.16 ± 0.00 J per breath. The greatest and least percentage reduction in dissipated energy was 68% and 33%, respectively.ConclusionsThe device bench tested in this study demonstrated a significant reduction in peak expiratory flow rate and dissipated energy, compared to ventilation with unregulated expiratory flow. Application of the device warrants further experimental and clinical evaluation.

Assessment of the long-term hydrological performance of a green roof system in stormwater control

Green roof systems (GRs) are effective tools for urban stormwater management. However, there is limited documentation of the long-term hydrological performance of GRs to support decision-making. This study evaluated long-term field monitoring records (7 years) from a 12-year-old GR, situated in a Moist Subtropical Mid-Latitude Climate, to analyze seasonality in and evolution of hydrological performance. The monitoring system was built within a pan lysimeter buried under substrate layers matching the surrounding GR. The monitoring results highlight the efficacy of this GR in long-term stormwater runoff control. The GR can retain 87% of the annual precipitation and return 54% of the precipitation to the atmosphere through evapotranspiration (ET) and sustain long-term event-based mean runoff volume reductions, peak flow reductions, and flow delays of 82%, 93%, and 4.3 h, respectively. The initial moisture content prior to events was highly correlated with hydrological performance, with a seasonal mean Spearman correlation coefficient of 0.47, suggesting the potential of enhancing ET from the GR to improve performance. Substrate water holding capacity increased over time, but no obvious changes in water retention performance were observed. These monitoring results from the aging GR demonstrate the effectiveness of GR systems for long-term stormwater management.

The Coupled Application of the DB-IWHR Model and the MIKE 21 Model for the Assessment of Dam Failure Risk

The phenomenon of global climate change has led to an increase in the frequency of extreme precipitation events, an acceleration in the melting of glaciers and snow cover, and an elevation of the risk of flooding. In this study, the DB-IWHR model was employed in conjunction with the MIKE 21 hydrodynamic model to develop a simulation system for the dam failure flow process of an earth and rock dam. The study concentrated on the KET reservoir, and 12 dam failure scenarios were devised based on varying design flood criteria. The impact of reservoir failures on flood-risk areas was subjected to detailed analysis, with consideration given to a range of potential failure scenarios and flood sizes. It was determined that under identical inflow frequency conditions, the higher the water level, the more rapid the breakout process and the corresponding increase in flood peak discharge. Conversely, for a given frequency of incoming water, an elevated water level results in a transient breach process, accompanied by a reduction in flood peak flow. Moreover, for a given water level, an increase in water frequency results in a reduction in breaching time, an extension of flood duration, and an increase in flood peak flow. The observed trend of flood spreading is generally north-south, and this process is highly compatible with the topographic and geomorphological features, demonstrating good adaptability.

Physically-based modelling of UK river flows under climate change

This study presents the model setup and results from the first calibrated, physically-based, spatially-distributed hydrological modelling of combined land cover and climate change impacts on a large sample of UK river catchments. The SHETRAN hydrological model was automatically calibrated for 698 UK catchments then driven by the 12 regional climate model projections from UKCP18, combined with urban development and natural flood management scenarios. The automatic calibration of SHETRAN produces a median Nash-Sutcliffe efficiency value of 0.82 with 581 catchments having a value greater than 0.7. 24 summary metrics were calculated to capture changes to important aspects of the flow regime. The UKCP18 realisations in SHETRAN indicate that a warming climate will cause river flows, on average, to decrease. These decreases are simulated to be greatest in the south and east of the UK, with droughts becoming longer and more severe. While high flows also decrease on average, an increased number of extremes are exhibited, implying a greater number of extreme flood events in the future, particularly in the north and west of the UK. In the urban development scenarios, for flood events there is an increase in flow with the increased urbanization, with the 1 in 3-year peak flow event showing the greatest increase. The natural flood management scenarios consider the effect of increasing woodland and adding surface water storage ponds. The inclusion of these features produces a complex response but overall, the modelling shows a reduction in low, median, and high flows, although the more extreme the flow event the smaller the percentage change in flow. Simulated timeseries and summary metric datasets are freely available on the CEDA archive.

Stormwater runoff volume reduction and pollutant removal efficiency via bioretention cell using rock wool as the media

ABSTRACT Bioretention cells have been widely used in stormwater management. Media plays an important role in stormwater runoff reduction and pollutant removal. A novel bioretention media of rock wool has been proposed, and its effect on stormwater runoff reduction was investigated via a laboratory-scale experiment. The results showed that compared with the conventional bioretention (CB) using medium sand as media, the volume capture ratio of annual rainfall (VCRAR) of the rock wool bioretention (RWB) was 2.66–5.5% higher, and the peak flow reduction rate was 2.97–11.32% higher. The removal efficiency rates of the RWB on COD, NH4+ -N, TN, and TP were 25–30%, 10–31%, 20–40%, and 5–14% higher than the CB, respectively. The removal efficiency of the RWB on botht Pb and Zn was &amp;gt;99%. The microbial high-throughput sequencing results showed that the RWB can provide a better breeding environment for Bacteroides and Actinobacteria, which is conducive for the removal of pollutants. The RWB had a better stormwater runoff volume reduction rate and pollutant removal efficiency than the CB, therefore, it could be used as a better media for bioretention cells to improve stormwater management efficiency by using rock wool, obtained from construction waste, as the media.

Fournier’s gangrene in voluminous inguinoscrotal herniation: Case report and review of literature

Introduction: Fournier’s gangrene (FG) is a polymicrobial life-threatening infection that affects perineal region and may extend to genitalia and abdominal wall. Necrotizing fasciitis is a rare condition and its association with large inguinoscrotal hernia even rarer. With high mortality rate, some predisposing factors are diabetes and immunodeficiency. Case presentation: We report a case of a 48-year-old man with Fournier’s gangrene associated with voluminous inguinoscrotal herniation which evolved to hernia sac exposure after debridement. Discussion: FG pathophysiology initiates with a localized infection by a combination of gram positive, gram negative and anaerobic bacteria, and its advancing leads to local inflammatory response, thrombosis, blood flow reduction and ischemia. Diagnosis depends on clinical presentation and image evaluation. Conclusion: FG management has been standard in the literature, however its association with inguinoscrotal hernias have not been considered in guidelines. Early diagnosis and proper clinical and surgical treatment are fundamental to avoid life-threatening complications and morbidities.