Type Of Drainage Research Articles

Features of the numerical modeling of the hydrogeological conditions of the soil massive during the excavation of the pit in the Plaxis software complex

The construction of multi-storey civilian buildings, especially in the central districts of cities, is often accompanied by a developed underground part, which requires deep pits. The construction of such pits often leads to a change in the hydrogeological condition at and near the construction site.
 This paper presents a comparison of the stress-strain state of the " base - pit enclosure" system, depending on the method of modeling hydrogeological conditions.
 The study is divided into two stages: determination of the main features of the Plaxis software complex toolkit for modeling and determining pore water pressures; creating of numerical models and performing calculations. . The first part of the study describes the basic principle of determining stresses in saturated soils, pore pressure calculation types, hydraulic boundary conditions, and types of soil drainage.
 In the second part of the study, the numerical models were developed in Plaxis 2D, based on the real object and hydrogeological conditions at the construction site. The two most popular methods for modeling hydrogeological conditions during dry excavation in the pit are described. A step-by-step calculation is performed taking into account the stages of excavation in the pit and dewatering and the construction of retaining structures according to the scheme provided by the design solutions.
 The results of the calculations demonstrate the difference in the obtained values of forces and horizontal displacements of the retaining wall for models created using different methods of setting the hydrogeological conditions of the base.
 In order to improve the accuracy of calculations and determine the impact of soil permeability, the impact of the stratigraphy of the base was excluded by solving theoretical problems with a homogeneous soil massif composed of clay or sandy soil with groundwater filtration rates in a wide range (kx=ky=0.001...6m/day). Based on the results obtained, it was found that both methods correlate with each other in the case of the presence of poorly filtering soils with a filtration coefficient of k=0.001...0.05 m/day, the calculations demonstrated similarity in the displacements and forces of the retaining wall in such schemes up to 97.9-99.9%. Instead, in the case of soils with high water permeability (k=0.4...6 m/day), the difference in results is up to 56.5%.

Internal versus external biliary drainage in malignant biliary obstructions: is there a difference in the rate of infection?

Percutaneous biliary drainage is a frequently used method to provide biliary decompression in patients with biliary obstruction. To investigate the between drainage type and infection risk in patients treated with internal-external and external biliary drainage catheterization for malignant biliary obstruction. A total of 410 patients with malignant biliary obstruction who underwent internal-external or external biliary drainage catheterization between January 2012 and October 2016 were retrospectively evaluated. We investigated the correlation between percutaneous biliary drainage technique and infection frequency by evaluating patients with clinical findings, bile and blood cultures, complete blood counts, and blood biochemistry. There was no statistically significant difference between the selected patient groups (internal-external or external biliary drainage catheter placed) in terms of age, sex, primary diagnosis, receiving chemotherapy, catheter sizes, and outpatient-patient status. After catheterization, catheter-related infection was observed in 49 of 216 (22.7%) patients with internal-external and 18 of 127 (14.2%) patients with external biliary drainage catheters, according to the defined criteria. There was no difference in infection rate after the biliary drainage in the two groups (P > 0.05). There was also no difference concerning frequently proliferating microorganisms in bile cultures. Internal-external biliary drainage catheter placement does not bring an additional infection risk for uninfected cholestatic patients whose obstruction could be passed easily in the initial drainage.

Risk of repeated drainage in pediatric septic arthritis: patient or method?

How drainage of septic arthritis should be performed remains controversial. The aim of the present study was to compare arthrocentesis (Ac) using double intra-articular needle lavage to arthrotomy (At) as first-line drainage treatment for pediatric hip and knee septic arthritis. The secondary objective was to identify risk factors of second articular drainage. A retrospective review of medical records of children with knee and hip septic arthritis was conducted. Inclusion criteria were: children treated for septic arthritis between 2014 and 2020 with a positive culture of joint fluid. Clinical, biological, radiographical and ultrasound data were recorded at presentation and during follow-up. Patients were divided into 2 groups according to the type of drainage performed: Ac or At. 25 hips and 44 knees were included, 42 treated by Ac (15 hips, 27 knees) and 27 by At (10 hips, 17 knees). There is no significant difference between Ac and At regarding the need for repeated drainage and Ac nor At was reported as risk factor for repeated drainage. The presence of associated musculoskeletal infection (MSI) was a significant risk factor of repeated drainage [odds ratio = 11.8; 95% confidence interval = 1.2-114.2; P < 0.001]. Significantly more associated MSI ( P < 0.001), level I virulence germs ( P < 0.001) and positive blood culture (<0.001) were found in patients who underwent repeated drainage. There was no significant difference between Ac and At regarding rate of repeated drainage. The risk factors for repeated drainage were: associated with MSI, virulent germs and positive blood culture.

Lake-TopoCat: a global lake drainage topology and catchment database

Abstract. Lakes and reservoirs are ubiquitous across global landscapes, functioning as the largest repository of liquid surface freshwater, hotspots of carbon cycling, and sentinels of climate change. Although typically considered lentic (hydrologically stationary) environments, lakes are an integral part of global drainage networks. Through perennial and intermittent hydrological connections, lakes often interact with each other, and these connections actively affect water mass, quality, and energy balances in both lacustrine and fluvial systems. Deciphering how global lakes are hydrologically interconnected (or the so-called “lake drainage topology”) is not only important for lake change attribution but also increasingly critical for discharge, sediment, and carbon modeling. Despite the proliferation of river hydrography data, lakes remain poorly represented in routing models, partially because there has been no global-scale hydrography dataset tailored to lake drainage basins and networks. Here, we introduce the global Lake drainage Topology and Catchment database (Lake-TopoCat), which reveals detailed lake hydrography information with careful consideration of possible multifurcation. Lake-TopoCat contains the outlet(s) and catchment(s) of each lake; the interconnecting reaches among lakes; and a wide suite of attributes depicting lake drainage topology such as upstream and downstream relationship, drainage distance between lakes, and a priori drainage type and connectivity with river networks. Using the HydroLAKES v1.0 (Messager et al., 2016) global lake mask, Lake-TopoCat identifies ∼ 1.46 million outlets for ∼ 1.43 million lakes larger than 10 ha and delineates 77.5×106 km2 of lake catchments covering 57 % of the Earth's landmass except Antarctica. The global lakes are interconnected by ∼ 3 million reaches, derived from MERIT Hydro v1.0.1 (Yamazaki et al., 2019), stretching a total distance of ∼10×106 km, of which ∼ 80 % are shorter than 10 km. With such unprecedented lake hydrography details, Lake-TopoCat contributes towards a globally coupled lake–river routing model. It may also facilitate a variety of limnological applications such as attributing water quality from lake scale to basin scale, tracing inter-lake fish migration due to changing climate, monitoring fluvial–lacustrine connectivity, and improving estimates of terrestrial carbon fluxes. Lake-TopoCat is freely accessible at https://doi.org/10.5281/zenodo.7916729 (Sikder et al., 2023).

Pigtail Catheter versus Large Bore Chest Tube for the Management of Spontaneous Pneumothorax in Children: A Retrospective Study.

Pigtail catheter (PGC) insertion due to spontaneous pneumothorax (SPT) in the pediatric population has increased markedly in the last years. However, only few studies examined its efficacy in terms of length of hospitalization, rate of complications, and especially pain management comparing to large bore catheter (LBC) insertion. We sought to compare analgetic drug consumption, efficacy, and complication rate between PGC and LBC in children with SPT. This is a single-center retrospective study of pediatric patients that were admitted to the Schneider Children's Medical Center between 2013 and 2021 with a diagnosis of SPT. The following data were collected: type of drainage (PGC or LBC), duration of drainage, length of hospitalization, number of X-rays, complication rate, surgery during hospitalization, readmission due to SPT, and pain management. Seventeen PGC and 23 LBC were inserted in our study. No differences were noted in terms of hospitalization length, tube reposition or replacement, and recurrence of SPT between the groups. Patients with PGC underwent less X-rays comparing to the LBC group (3 X-rays vs. 5, median, p < 0.005). Oral analgesic use in terms of length of therapy was significantly lower in the PGC group than in the LBC group (1 vs. 3+ days, median, p < 0.05). There was no major complication in this cohort. PGC is an effective, safe, and less painful alternative compared with a LBC for the drainage of SPT in children.

Understanding the exchange process between ground and surface water using mini drive point piezometer and mathematical models to identify suitable managed aquifer recharge sites.

In the current study, subsurface characteristics within the complex formation of the Shilabati basin system of West Bengal, India, extending over an area of 3888 km2, have been estimated using a cost-effective piezometer and MIKE FEFLOW package based on a steady-state numerical model. Pore size and fine particle content of streambeds are affected by two opposing flow contraptions. Such opposite flow conditions are likely to affect the hydraulic conductivity of the streambed. However, analogies of the hydraulic conductivity (Kh) of streambeds for losing and gaining streams have not been well documented in the recent past. The Kh value from the piezometer has been highest at the Dakshin Pairachali site (6.765 m/day), with the stream gaining water from the discharge of the local aquifer. Analysis of the stream-aquifer interaction using the FEFLOW model has allowed us to understand the groundwater water head of the basin ranging from 160.33 to 0.32 m.a.s.l (meters above sea level). The present study also constitutes the first attempt for the identification of suitable sites for the implementation of managed aquifer recharge (MAR) technology in West Bengal, India, to manage extreme drought events. The suitable sites have been identified by means of three fuzzy multi-criteria decision analysis based on nine criteria: river discharge, moisture content, porosity, drainage type, rainfall, land use type, geology, aquifer material, and hydraulic conductivity. To design a radial collector well and infiltration gallery for the selected site in an anisotropic, homogeneous, unconfined, and semi-infinite aquifer near a fully penetrating stream, a pumping test has been conducted to optimize a safe yield of 12.096 MLD (megaliters per day).

Long-term observation of global nuclear power plants thermal plumes using Landsat images and deep learning

Thermal discharge from nuclear power plants poses a threat to the received natural water bodies, but the long-term extent and intensity of their surface thermal plumes remain unclear. In this study, we proposed a method to determine the background area for each drainage outlet and delineate the mixed surface thermal plumes based on 7,172 Landsat thermal infrared images. We further used a deep convolutional neural network integrated with prior location knowledge to extract core surface thermal plumes for 74 drainage outlets of 66 nuclear power plants worldwide. Our final model achieved a mean Intersection over Union (mIoU) of 0.8998 and an F1 score of 0.8886. We found that the mean maximal water surface temperature (WST) increment of the studied plants globally was 4.80 K. The Tianwan plant in China experienced the highest WST increase (8.51 K), followed by the Gravelines plant in France and the Ohi plant in Japan (7.91 K and 7.71 K, respectively). The Bruce plant in Canada had the largest thermal-polluted surface area (7.22 km2). We also provided the dataset, Global Coastal Nuclear power plant Thermal Plume (GCNT-Plume), to describe the long-term occurrence of water surface thermal plumes. Three influencing factors of the water surface thermal plume were further analyzed in this study, including total capacity, drainage type, and location type, which were associated with operating power, drainage method, and geographical features, respectively. Total capacity was more statistically related to the maximum of WST increment under shallow drainage condition. The mean WST increment of shallow drainage was 1.22 K higher than that of deep drainage. Surface plumes larger than 4 km2 frequently occurred in the Great Lakes, while small surface thermal plumes (< 1 km2) were primarily found in estuaries. The proposed method provides an important framework for future operational water surface thermal plume detection using remotely sensed observations and deep learning.

Incidence and Surgical Outcomes of Intracranial Arachnoid Cysts: A Systematic Review Comparing Endoscopic Fenestration, Open Craniotomy and Cystoperitoneal Shunt Approaches

ABSTRACT Background: Arachnoid cysts (ACs) are non-neoplastic collections of cerebrospinal fluid, often posing challenges in diagnosis and management due to their rarity and varied clinical presentations. This systematic review aims to investigate the frequency of ACs, analyse optimal intervention approaches and evaluate neurological complications postoperatively. Materials and Methods: A systematic search of Science Direct, PubMed and Cochrane databases was conducted using controlled vocabulary terms and keywords. Inclusion criteria encompassed studies focusing on adults with symptomatic ACs requiring surgical intervention. Data extraction involved factors influencing subdural haemorrhage, surgical techniques, drainage types and imaging approaches. Adherence to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines ensured methodological rigor and transparency. Results: The review identified multiple surgical approaches, including microsurgical fenestration, endoscopic fenestration and cystoperitoneal shunt, tailored to different cyst locations. Studies showed cystoperitoneal bypass as effective for supratentorial cysts, endoscopic fenestration for midline cysts and cystoperitoneal shunt for infratentorial cysts. Notably, endoscopic fenestration exhibited a 90% success rate, while cystoventricular drainage emerged as an alternative option. However, limitations in comparative studies and variations in follow-up durations hindered comprehensive analyses. Conclusion: Cystocysternostomy, preferably minimally invasive, showed promising outcomes in managing ACs. Wide endoscopic fenestration was recommended without causing damage to adjacent structures. Surgical adaptation for uncontrolled bleeding during procedures was suggested. Intracranial shunts were preferred due to lower infection risks. Postoperative care involving anticonvulsants and conservative antibiotic therapy exhibited low complication rates. Despite limitations in available evidence, this review highlights potential effective interventions for managing ACs, emphasising the need for further comprehensive studies.

Analysis of seasonal variation in the hydrological behaviour of a field combining surface and tile drainage

Agricultural drainage increases hydrological connectivity between fields and receiving environments. Tile drains and drainage ditches are the main drainage types studied at the field scale. They can be associated with temporary surface drains to improve the removal of surface water. Combining surface drains with tile drains is likely to modify surface runoff and soil water dynamics. The behaviour of tile-drained fields has been studied at the event scale, but few studies have been conducted over a full hydrological year, and no studies have quantified water volumes in a field combining surface and tile drainage. So quantifications of water partition between surface drainage, tile drainage and soil water are needed to understand the hydrological behaviour of a field combining surface and tile drains. Moreover, at the event scale, few studies showed macropores can contribute to tile drain runoff but the partition between preferential flow and matrix flow is still unclear. It needs to be study depending on several parameters as soil type, soil water content or agricultural practice for a better understanding. In this study, high temporal resolution quantification of surface runoff and tile drainage was conducted for two full hydrological years to study hydrological functioning of the field using the water balance for a drained field. Soil water pathways were studied under dry and saturated soil conditions, tracing water by measuring stable isotope (18O and 2H) concentrations in rainwater, soil water, and surface and tile runoff. Runoff quantification showed that surface drainage and tile drainage respectively transferred 44% and 20% of annual effective rainfall. However, water balance showed that, at the annual scale, 65% of infiltrating water was not captured by tile drains. At the event scale, water tracing showed a season variation in macropores contribution depending on soil hydric state. Under dry conditions, rainwater was directly transferred to tile drains, likely through macropores. On saturated soil, pre-event soil water content provided most of the water flowing out from the tile drain, but rainfall can contribute up to 25% of the water flowing out from the tile drains. Combining water balance and water trancing allowed to propose a conceptual model for surface and tile drainage hydrological functioning at the event scale.

Evaluation of the K-wire technique for external urinary drainage in pediatric laparoscopic pyeloplasty

Urinary drainage is usually left in place after laparoscopic pyeloplasty to limit the risk of complications, such as urinary leakage. The procedure is sometimes laborious and complications may occur. Prospective evaluation of the Kirschner technique for urinary drainage during pediatric laparoscopic pyeloplasty. This technique (Upasani etal., J Pediatr Urol 2018) involves introducing a nephrostomy tube (Blue Stent) with a Kirschner wire during laparoscopic transperitoneal pyeloplasty. We evaluated this technique by analyzing 14 consecutive pyeloplasties (53% on female patients, median age 10 years (6-16 years), on the right side in 40%) performed by a single operator between 2018 and 2021. The drain and urinary catheter were clamped and the perirenal drain removed on day 2. The stent was removed during consultation between days 7 and 15. The median duration of surgery was 155±7min. Urinary drainage was installed within 5min, without the need for radiological control and with no complications. All drains were correctly placed, with no drain migration or urinoma. Median hospital stay was 2±1 days. One patient developed pyelonephritis (D8). The stent was removed without difficulty or complications. One patient presented an 8-mm lower calyx urinary stone at two months, revealed by macroscopic hematuria, necessitating extracorporeal shock wave lithotripsy. The study design was based on a homogeneous series of patients, without comparison with another drainage technique or procedures performed by another operator. A comparison with other techniques might have been informative. Before this study, we tested various types of urinary drainage, to optimize performance. This technique was considered the simplest and least invasive. External drain placement with this technique was rapid, safe, and reproducible in children. It also made it possible to test the tightness of the anastomosis and to avoid the need for anesthesia for drain removal.

Types of Drains in Surgery

Surgery is a medical discipline that has advanced significantly in recent decades thanks to advances in technology and medical research. Surgical drains are devices used to evacuate excess fluids that accumulate in the surgical wound. There are different types of drains that can be used depending on the area intervened and the type of fluid to be evacuated. Each type of drainage has specific advantages and disadvantages, and their choice will depend on the characteristics of the patient and the procedure.

A multi-spatial analysis and the balanced requirements of freshwater mussels (Bivalvia: Unionidae) and urban inhabitants in the Cuyahoga River watershed

Water quality in the Cuyahoga River, a national heritage river of the United States, has improved greatly since the infamous river fire of 1969, but much of the watershed faces combined demands of a state scenic river valued for nature and the primary water source for surrounding cities. A comparative analysis of mussel abundance was applied to test success between water improvements and mussel assemblages in two similarly sized sub-watersheds, the upper reaches of the Cuyahoga River and an isolated tributary stream, Tinkers Creek. Multivariate GIS/remote sensing tools and government data resources were applied to contrast variation in lands use, soil types, and potential impacts from impoundments. Mussel populations declined in much of the Upper Cuyahoga River from 1990 to present, while in Tinkers Creek and the West Branch Cuyahoga River, both areas surrounded by residential lands, mussel species changed from a slow water species to species associated with flowing streams. Major structural differences among these stream reaches included regulated flow from reservoirs and consequentially poor soil drainage type in much of the Upper Cuyahoga River, while extensive improvements in Tinkers Creek enhanced flow dynamics and produced well-draining soils. Thus, the mussel assemblages appeared sustained despite a trend towards more human use where water flowed free.

A brief overview to give a new perspective on mole drainage

Draining excess water from the soil is the general purpose of drainage. Thus, soil protection is provided and product losses are prevented. Mole drainage consists of underground galleries that act as piped drainage. This type of drainage is mostly used successfully in clay, organic, and highly cohesive soils. It is used successfully in areas with high groundwater, during the improvement of salty and sodium soils. The biggest benefit of mole drainage is cheap and economical. In the mole drainage method, tunnels are opened under the tillage depth with a torpedo-shaped piece at the end of a foot extending under the soil. These tunnels are called mole drains. In the mole drainage method, the channels are built with mole drain plows and subsoilers. In order to benefit more effectively from mole drainages, parameters such as suitable working width, working depth and slope must be finely adjusted. For this, modern alternatives such as GPS and laser positioning systems can be used.

Compressibility characteristics of clays in the Red River Delta

The Red River Delta (RRD) is the second largest delta in Vietnam and is a significant economic zone in the country, encompassing important cities and economic zones. Geologically, the delta consists of clay layers distributed all over its area, which strongly impact the foundation designs of the infrastructure system (e.g., highways, industrial parks, harbors). However, up to date, there were no comprehensive studies on the compressibility characteristics of the clays in the delta. This study presents a primary study on some compressibility characteristics of clays in the whole delta with an emphasis on the use of CPTu data in the interpretation. For this, high-quality field and laboratory test results obtained from four research test sites and eight project sites were analyzed to depict the characteristics. The results indicate that the clays in the delta are typically soft to medium stiff and normally consolidated to slightly overconsolidated, which represent typical characteristics of young Holocene deposits. The compression index (Cc) of the clays was found to have good correlations with natural water content (Wn) or in-situ void ratio (e0). The ratio of radial coefficient of consolidation from a consolidation test with a central drain (CD) to the vertical coefficient of consolidation from the standard consolidation test (i.e., cr,CD/cv) from the 4 research test sites is on average 2.76 (log t method) and 2.32 (root t method) and these average ratios are found typical for deltaic soil deposits. The correlations for the remolded samples indicate that the drainage type has a strong influence to the induced coefficients of homogeneously remolded soils. Results from this study help geotechnical engineers have a general view on the compressibility characteristics of the clays in the delta, which in turn helps secure optimal foundation design solutions.

A health risk model for rural households based on the distribution of multi pollutants.

Rapid consumerism and improper waste disposal create widespread environmental degradation through the air, water sources and landfills in India's rural areas. This work develops a health risk prediction model to score villages based on quantitative and qualitative factors. Quantitative observations regarding pollutant levels and qualitative responses are collected from various households. that are risk labelled against WHO standards. The health risk model is designed to correlate the qualitative factors. A total of 2,370 rural households spread across three districts of Karnataka were selected. The study found that the health risk score predicted by the model has a higher significant correlation (0.8) to various existing pollutant factors. The study found that source of drinking water (0.87), quality of drinking water (0.81), drainage canal availability (0.72), type of drainage (0.73), stagnant water (0.71), toilet availability (0.83), maintenance frequency (0.83), cooking fuel type (0.77), cigarette use (0.71), garbage piles up (0.73) and the percentage composition of wastes (0.74) was found to have a higher positive correlation to the health of rural households. The villages with higher health risks can be identified, and suitable mitigation plans can be designed to mitigate the health risk by state authorities.

Patients’ Perceptions of Experiences of Postoperative Chest Drain Tube Insertion: A Pilot Survey

Pleural drainage is a routine procedure conducted after thoracotomy and thoracoscopy. It is used to remove air or excess fluid from a pleural cavity and enables proper lung expansion. Essential elements of care provided during hospitalization and treatment include meeting patients' growing expectations and continually improving quality while optimizing safety. This study aimed to explore patients' experiences with pleural drainage after thoracic surgery and their correlation with socio-demographic data. A pilot survey with an exploratory design was conducted at a large teaching hospital in Poland, in the Department of Thoracic Surgery at the University Clinical Centre in Gdansk. The study involved the analysis of 100 randomly selected subjects with a chest tube drain. A self-designed questionnaire was used to collect social, demographic, and clinical data. Twenty-three questions related to experiences with pleural drainage, ailments, limitations in daily functioning, and security with a chest tube were evaluated using a 5-point Likert scale. Patients completed the questionnaire on the third postoperative day. Individuals fitted with a traditional water-seal drainage system felt safer than those from the digital drainage group (p = 0.017). Statistically significant differences were found in the assessment of nursing assistance (p = 0.025); the number of satisfied patients was greater in a group of unemployed people. No correlation was found between demographic and social factors and the patients' sense of security (gender: p = 0.348, age: p = 0.172, education level: p = 0.154, professional activity: p = 0.665). Demographic and social characteristics did not significantly affect patients' sense of safety with chest drainage types. Patients with traditional drainage felt significantly safer than patients with digital drainage. Patient knowledge of pleural drainage management was not satisfactory, with a number of patients indicating a lack of knowledge in this area. This is important information that should be considered when planning measures to improve the quality of care.

Quantification of outflow resistance for ureteral drainage devices used during ureteroscopy.

Since renal pelvis pressure is directly related to irrigation flowrate and outflow resistance, knowledge of outflow resistance associated with commonly used drainage devices could help guide the selection of the type and size of ureteral access sheath or catheter for individual ureteroscopic cases. This study aims to quantitatively measure outflow resistance for different drainage devices utilized during ureteroscopy. With measured irrigation flowrate and renal pelvis pressure, outflow resistance was calculated using a hydrodynamic formula. After placement of a drainage device into a silicone kidney-ureter model, a disposable ureteroscope with a 9.5-Fr outer diameter was inserted with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope from varying heights above the renal pelvis. Renal pelvis pressure was measured directly from the port of the kidney model using a pressure sensor (Opsens, Canada). Outflow resistance was determined by plotting flowrate versus renal pelvis pressure. All trials were performed in triplicate for each drainage device inserted. Flowrate was linearly dependent on renal pelvis pressure for all drainage devices tested. Outflow resistance values were 0.2, 1.1, 1.4, 3.9, and 6.5 cmH2O/[ml/min] for UAS 13/15 Fr, UAS 11/13 Fr, UAC 6 Fr, UAC 4.8 Fr, and UAC 4.0 Fr, respectively, across the range of commonly used irrigation flowrates. In this study, outflow resistance of different ureteral drainage devices was quantitatively measured. This knowledge can be useful when selecting which type and size of drainage device to insert to maintain safe renal pelvis pressure during ureteroscopy.

Features of the urban environment associated with Aedes aegypti abundance in high-rise public apartments in Singapore: An environmental case-control study.

Aedes aegypti abundance in residential estates is hypothesized to contribute to localised outbreaks of dengue in Singapore. Knowing the factors in the urban environment underlying high Ae. aegypti abundance could guide intervention efforts to reduce Ae. aegypti breeding and the incidence of dengue. In this study, objective data on Ae. aegypti abundance in public apartment blocks estimated by Singapore's nationally representative Gravitrap surveillance system was obtained from the National Environmental Agency. Low and high abundance status public apartment blocks were classified based on the Gravitrap Aegypti Index, corresponding to the lowest and highest quartiles respectively. An environmental case-control study was conducted, wherein a blinded assessment of urban features hypothesised to form breeding habitats was conducted in 50 randomly sampled public apartment blocks with low and high abundance statuses each. Logistic regression was performed to identify features that correlated with abundance status. A multivariable logistic model was created to determine key urban features found in corridors and void decks which were predictive of the Ae. aegypti abundance status of the public apartment block. At a statistical level of significance of 0.20, the presence of gully traps [Odds Ratio (OR): 1.34, 95% Confidence Interval (CI): 1.10, 1.66], age of the public apartment block [OR: 2.23, 95% CI: 1.48, 3.60], housing price [OR: 0.33, 95% CI: 0.16, 0.61] and corridor cleanliness [OR: 0.67, 95% CI: 0.40, 1.07] were identified as important predictors of abundance status. To reduce Ae. aegypti abundance around public apartment blocks and potential onward dengue transmission, gully traps could be remodelled or replaced by other drainage types. Routine inspections of Ae. aegypti breeding should be targeted at older and low-income neighbourhoods. Campaigns for cleaner corridors should be promoted.

Arteriovenous fistulas in the craniocervical junction region: With vs. without spinal arterial feeders.

Arteriovenous fistulas (AVFs) in the craniocervical junction (CCJ) region are a rare occurrence with special clinical manifestations. This study retrospectively reviewed patients with CCJ AVFs treated at our neurosurgical center, aiming to enhance the understanding of CCJ AVFs. A total of 113 patients with CCJ AVFs treated at our neurosurgical center between January 2013 and December 2020 were enrolled. They were grouped as patients with CCJ AVFs with spinal arterial feeders (n = 20) and patients with CCJ AVF without spinal arterial feeders (n = 93). Clinical presentation, angiographic characteristics, intraoperative findings, and treatment outcomes were analyzed. The patients' median age was 55 years (IQR 47.5-62 years). The proportion of males in the group without spinal arterial feeders was significantly higher (p = 0.001). Subarachnoid hemorrhage (SAH) was the most common clinical presentation, especially in the group with spinal arterial feeders (p < 0.001). There were significant differences in AVF type, fistula location, and direction of the venous drainage between the two groups (p < 0.001). Intervention embolization combined with microsurgery was more common in treating AVFs with spinal arterial feeders (p = 0.006). Spinal arterial feeders did not affect the outcome (p = 0.275). SAH was the most common presentation of CCJ AVFs in this study. Microsurgery and interventional embolization were optional treatment strategies. The angioarchitecture of CCJ AVFs was essential for selecting treatment strategies.

Revealing the sources of arsenic in private well water using Random Forest Classification and Regression.

Exposure to arsenic through private drinking water wells causes serious human health risks throughout the globe. Water testing data indicates there is arsenic contamination in private drinking water wells across New Jersey. To reduce the adverse health risk due to exposure to arsenic in drinking water, it is necessary to identify arsenic sources affecting private wells. Private wells are not regulated by any federal or state agencies through the Safe Drinking Water Act and therefore information is often lacking. To this end, we have developed machine learning algorithms including Random Forest Classification and Regression to decipher the factors contributing to higher arsenic concentration in private drinking water wells in west-central New Jersey. Arsenic concentration in private drinking water wells served as a response variable while explanatory variables were geological bedrock type, soil type, drainage class, land use/cover, and presence of orchards, contaminated sites, and abandoned mines within the 152.4-meter (500 ft) radius of each well. Random Forest Classification and Regression achieved 66 % and 55 % prediction accuracies for arsenic concentration in private drinking water wells, respectively. Overall, both models identify that bedrock, soil, land use/cover, and drainage type (in descending order) are the most important variables contributing to higher arsenic concentration in well water. These models further identify bedrock subgroups at a finer scale including Passaic Formation, Lockatong Formation, Stockton Formation contributing significantly to arsenic concentration in well water. Identification of sources of arsenic contamination in private drinking water wells at such a fine scale facilitates development of more targeted outreach as well as mitigation strategies to improve water quality and safeguard human health.