Fluid Sediment Research Articles

Influence of inelastic collision on the dynamic behavior of particle sedimentation in high-viscosity fluids

To further understand the characteristics of particle–fluid flow, the particle sedimentation process in a high-viscosity fluid is conducted with both experimental and numerical methods. In this work, inelastic collisions between particles during the sedimentation process are observed. Different from the sedimentation in a low-viscosity fluid, the increase of particle sedimentation velocity can be found due to the inelastic collisions in a high-viscosity fluid. This phenomenon is more obvious with the increase of the particle volume fractions and the viscosity of the fluid. The necessary conditions for the inelastic collision phenomenon are determined based on the viscous dissipative dynamics of particle collisions. According to the experimental and numerical results, the interactions between particles in high-viscosity liquids are mainly the inelastic collisions which caused the particle aggregation. The correction coefficient of particle sedimentation velocity equation is obtained, and the applicability of the equation for the sedimentation in a high-viscosity fluid is improved.

Formation of the Figge Maar Seafloor Crater During the 1964 B1 Blowout in the German North Sea

In 1964, exploration drilling in the German Sector of the North Sea hit a gas pocket at ∼2900 m depth below the seafloor and triggered a blowout, which formed a 550 m-wide and up to 38 m deep seafloor crater now known as Figge Maar. Although seafloor craters formed by fluid flow are very common structures, little is known about their formation dynamics. Here, we present 2D reflection seismic, sediment echosounder, and multibeam echosounder data from three geoscientific surveys of the Figge Maar blowout crater, which are used to reconstruct its formation. Reflection seismic data support a scenario in which overpressured gas ascended first through the lower part of the borehole and then migrated along steeply inclined strata and faults towards the seafloor. The focused discharge of gas at the seafloor removed up to 4.8 Mt of sediments in the following weeks of vigorous venting. Eyewitness accounts document that the initial phase of crater formation was characterized by the eruptive expulsion of fluids and sediments cutting deep into the substrate. This was followed by a prolonged phase of sediment fluidization and redistribution widening the crater. After fluid discharge ceased, the Figge Maar acted as a sediment trap reducing the crater depth to ∼12 m relative to the surrounding seafloor in 2018, which corresponds to an average sedimentation rate of ∼22,000 m3/yr between 1995 and 2018. Hydroacoustic and geochemical data indicate that the Figge Maar nowadays emits primarily biogenic methane, predominantly during low tide. The formation of Figge Maar illustrates hazards related to the formation of secondary fluid pathways, which can bypass safety measures at the wellhead and are thus difficult to control.

A Combined O/U-Tube Oscillatory Water Tunnel for Fluid Flow and Sediment Transport Studies: The Hydrodynamics and Genetic Algorithm

This study proposes an oscillatory water tunnel (O/U-tube) equipped with two impellers to drive flows. The O/U-tube consists of two modes: U-tube mode and O-tube mode. The former can generate oscillatory flow, while the latter can produce both oscillatory and unidirectional flows with velocities up to 1.6 m/s. The hydrodynamics of the U-tube and O-tube modes were examined analytically. For the U-tube mode, a sine-varying rotational speed for the impeller caused higher harmonic components for the velocity, owing to the local inertia and gravity forces. In the steady state of the O-tube mode, owing to the resistance force, the flow velocity was proportional to the rotational speed. To generate the target flow conditions, two open-loop control schemes were proposed according to the analytic approach for the U-tube mode and a genetic algorithm for the O-tube mode. The analytic approach was based on a hydrodynamic model with a given flow condition. In the genetic algorithm, the rotational speed was represented by a square root of the Fourier series. The optimal coefficients of the Fourier series to generate the target flow were determined by using the genetic algorithm and the hydrodynamic model. Both approaches were experimentally validated. Consequently, the O/U-tube with the open-loop schemes can be used to generate the desired oscillatory and unidirectional flows.

Abomasal impaction in buffaloes: Risk factors, clinical indicators, necropsy findings, and histology studies.

The present study aims to identify potential risk factors and most possible clinical indicators of abomasal impaction in buffaloes. Among the screened buffaloes (n = 636), the logistic model was fitted for 491 buffaloes because of the non-availability of parity-related data for 145 buffaloes. Third-trimester pregnancy, feeding paddy straw alone, and concurrent disorders were identified as the potential risk factors using multivariate regression analysis. The buffaloes reared by farmers devoid of land tended to have a higher incidence of abomasal impaction. Depressed demeanour, absence of rumination, abdominal guarding, scleral congestion, sunken eyeballs, anorexia, reduced dung output, abacus beads-like faeces, colic signs (straining to defecate, frequent lying down, and kicking at abdomen), tachypnea, and tachycardia were the most repeatedly noticed clinical signs in buffaloes diagnosed with abomasal impaction. Further, the principal component analysis revealed increased rumen fluid sedimentation time and chloride content, serum creatine phosphokinase, and blood neutrophil and eosinophil content along with decreased blood lymphocytes proportion, potassium, and chloride as the greatest indicators for abomasal impaction. Next to them, a higher rumen fluid methylene blue reduction time, serum urea nitrogen, and blood total leucocyte count, along with a lower serum albumin and blood haemoglobin were the best possible indicators for diagnosis. The necropsy findings of the buffaloes that died with abomasal disorders revealed an abomasum with increased dimensions and constant pitting on pressure. Furthermore, the histopathological studies showed degeneration and necrosis of the abomasal wall with infiltrated mononuclear cells. The results of the study help in designing a comprehensive evaluation mechanism for diagnosing abomasal impaction in buffaloes.

Barium stable isotopic composition of chondrites and its implication for the Earth

Barium is a refractory and fluid mobile element that is highly incompatible in basaltic systems. The elemental and isotopic compositions of Ba are used to trace fluid processes or sediment recycling during subduction. However, the Ba isotopic composition of primitive meteorites (chondrites), which represents the possible building blocks of terrestrial planets, is presently poorly known. Here, we report high precision Ba isotopic compositions of major types of chondrites using a double-spike method. Chondritic meteorites without clear terrestrial weathering show relatively homogeneous Ba isotopic distributions and have an average δ137/134Ba (the permil deviation of the 137Ba/134Ba ratio from the SRM3104a standard) value of 0.09 ± 0.09‰ (2SD, N = 14). Given the refractory and lithophile behavior of Ba and the limited variations of Ba isotope composition between various chondrite groups, this value can represent the Ba isotopic composition of the bulk Earth and the Bulk Silicate Earth (BSE). It is actually consistent with the present estimate of BSE (0.05 ± 0.06‰, Li et al., 2020; Nan et al., 2022) based on the measurements of mid-ocean ridge basalts and carbonatites. Small Ba isotope variations are observed between carbonaceous chondrite groups where CO and CV show slightly heavier (by 0.09‰) Ba isotopic compositions than CI and CM. Significant light stable Ba isotopes enrichment has previously been documented in calcium, aluminum-rich inclusions (CAIs) in the Allende CV chondrite, and the Ba isotopic differences between CO and CV might result from the various proportions of CAIs based on a mass balance calculation. However, the parent body of CI and CM might have experienced aqueous alteration and secondary carbonates are most likely responsible for their light Ba isotopic signatures.

3D Lattice Boltzmann Method-Discrete-Element Method with Immersed Moving Boundary Scheme Numerical Modeling of Microparticles Migration Carried by a Fluid in Fracture

SummaryBased on the LBM-IMB-DEM (coupled lattice Boltzmann method-discrete-element method with immersed moving boundary scheme) model, the 3D microparticles’ migration carried by a fluid in fracture is numerically investigated both considering and not considering the van der Waals adhesive force. A boundary cells’ tracing method called the layer-by-layer tracing method both applicable to 2D and 3D situations for IMB with high efficiency and accuracy is proposed, and based on its searching results, the contacts in DEM could be detected straightforwardly with a finite amount of computation. In the layer-by-layer tracing method, a limited number of points, including some cell centers and nodes, near the particle boundary are determined whether they are covered by the particle, and then the other cells in one layer could be precisely classified. In the contact detecting process for DEM, based on the boundary cells tracing results in IMB, the cells that are covered by no less than two particles are the potential cells where there may be contacts. For wall boundaries with irregular shapes, the wall solid boundary (WSB) cells are converted to circumcircle (or circumscribed sphere in 3D situation), and then the solid particle-wall interactions could be replaced by the interactions between the solid particles and those circumcircles or circumscribed spheres. Two cases, including single-particle sedimentation in a viscous fluid, two-particle Drafting-Kissing-Tumbling (DKT) simulation for both nonadhesive and adhesive particles, are used to validate the LBM-IMB-DEM method. Besides, multiparticle sedimentation tests for different particle radiuses are conducted to present the advantages of the layer-by-layer tracing method. At last, nonadhesive and adhesive microparticles’ liberation, transport, and retention carried by a fluid in fracture with irregular shapes are simulated. The numerical results show that the adhesive force that plays a dominated role for microparticles has significant effects on the mechanics of solid particles migration. Under the influence of adhesive forces, the microparticles tend to form a stable agglomerate and migrate as a whole, which is different from the situation for nonadhesive particles where they are relatively independent and basically migrate by layer. Besides, even if the fluid velocity is much lower than the critical velocity evaluated through force or torque analysis on a single particle, when the total hydrodynamic forces exerted on the agglomerate overcome the total adhesive force between the wall and the lower layer of particles, the agglomerate can start to move and liberate from the wall.

Efficient back analysis of multiphysics processes of gas hydrate production through artificial intelligence

Natural gas hydrate, a crystalline solid existing under high-pressure and low-temperature conditions, has been regarded as a potential alternative energy resource. It is globally widespread and occurs mainly inside the pores of deepwater sediments and sediments under permafrost area. Hydrate production via well depressurization is deemed well-suited to existing technology, in which the pore pressure is lowered, the natural gas hydrate is dissociated into water and gas, and the water and gas are produced from well. This method triggers multiphysics processes such as fluid flow, heat transfer, energy adsorption, chemical reaction and sediment deformation, all of which are dependent on the amount of gas hydrates remaining in the pores. Therefore, modeling of hydrate production is computationally intensive and expensive. While back-analysis through observed production history is essential for better understanding of the reservoir characteristics and reliable prediction for future gas hydrate production, a large number of required simulations makes it impractical. This study employs Artificial Intelligence (AI) to achieve an efficient back-analysis of the gas hydrate production conducted at the offshore Nankai site, Japan, in 2013. The results show that the AI-based metamodel is capable of reproducing outputs of heavy computation of the multiphysics processes and thus performs back-analysis greatly efficiently. The efficient AI-based metamodel also makes it possible to carry out sensitivity analysis and it is found that the permeability and the preyield plasticity parameter are most influential to reservoir responses. The approach of this study can be applicable to other reservoirs and will reveal the ground truth in-situ properties and the most influential properties, contributing to better understanding of reservoir behavior for future gas hydrate production.

Characterizing ancient and modern hydrothermal venting systems

Ancient hydrothermal vent complexes have released large volumes of greenhouse gases in the past causing global warming, and similar modern vent structures are potential geohazards. In the NE Atlantic, thousands of hydrothermal vent complexes were formed during the Paleocene-Eocene Thermal Maximum. In Java, Indonesia, the erupting Lusi sediment-hosted geothermal system caused the displacement of 40,000 people. In order to determine how ancient and modern hydrothermal venting systems are related, we map a well-defined buried hydrothermal vent complex offshore mid-Norway using 3D seismic reflection data and then compare it to the active Lusi eruption (since 2006) and the neighboring inactive Porong Structure. These are characterized using 2D seismic reflection data, borehole data and field observations. The venting structures are subcircular in plan-view and a few kilometers in diameter. They are funnel-shaped in profiles, with inward-dipping beds surrounding the conduits. The hydrothermal vent complex offshore mid-Norway reveals five seismically-distinct vent fill facies units. Importantly, two of the facies units are separated by an angular unconformity, clearly indicating that the depositional events within the vent fill were distinct. Hydrothermal fluids are interpreted to have led to the fluidization of mud-rich sediments which were erupted and deposited in and around the vent complex. Interpretation of a seismically transparent body along the conduit of the Norwegian venting structure, and the abrupt widening of the conduit at the Porong Structure, are interpreted to be caused by changes in fluid-flow dynamics as the fluids rise and get released from the host-rock. The hydrothermal venting systems in Java and offshore mid-Norway are found to be morphologically similar and are interpreted to form as the result of the transport and eruption of fluidized sediments.

Two-way coupling model for wave-induced oscillatory soil response around marine structures

Considerable efforts have been devoted to the topic of wave–seabed interactions in the last two decades because of growing offshore activities. The existing studies have based on one-way coupling approach. In this study, a new two-way coupling algorithm is proposed to overcome the contradiction at the fluid–sediment interface between physical process and the existing theoretical models. The numerical results indicates that the seabed responses obtained by the two-way coupling model are slightly lower than that of the one-way coupling model. However, the two-way coupling model significantly affects the Shields number that would further affect the scour process. Parametric analysis indicates that larger wave height, current velocity and soil permeability and smaller water depth, shear modulus and saturation degree would increase the difference of two coupling algorithms. Meanwhile, the difference between two coupling algorithms is significant around the mono-pile and dumbbell cofferdam, compared with the case without a structure.

Production of bio-stable fluid sediment from accumulation of cyanobacterial bloom biomass under various water depths

While fluid sediments normally formed through hydrodynamic erosion and transport was well known, the fluid sediments caused by organic matter accumulation and degradation in eutrophic lakes was rarely investigated. Here, the effects of cyanobacterial bloom biomass (CBB) accumulation and water depth on the occurrence of fluid sediments were studied. Within 30 days of experiments, the variation of sediment height firstly increased to the maximum with rising in water depth, then decreased due to the high hydraulic pressure. While the surface sediments density decreased slightly from 1.35 g cm−3 to around 1.32 g cm−3 without CBB accumulation, and CBB accumulation led to lower density (around 1.02 g cm−3) but higher shear stress of sediments. Through analyzing the extracellular polymeric substances (EPS), it was found that CBB accumulation improved the polysaccharide/protein ratios of sediment. The infrared analysis further indicated that the bound-EPS could protect fluid sediments bio-stabilization. Meanwhile, the enriched Acinetobacter, Pseudomonas in sediments with CBB accumulation might play roles in EPS production, which benefited the bio-stabilization of fluid sediments. Furthermore, the stability of fluid sediments increased with increase in water depth, and the resuspension of biological fluid sediments would occur more likely in the low water depth area. Altogether, this study reported the formation and stability of the biological fluid sediments in eutrophic shallow lakes, and could help provide clues against sediment resuspension in lake ecosystems.

Effects of accumulated cyanobacterial bloom biomass contents on the characteristics of surface fluid sediments in a eutrophic shallow lake

In eutrophic shallow lakes, cyanobacterial blooms will occur frequently and then accumulate on sediments, leading to the variation in the surface sediment properties. In this study, the influence of accumulated cyanobacterial blooms biomass (CBB) content on surface sediment properties was determined in microcosm experiments through monitoring surface sediment physicochemical and rheological properties. During one-month incubation, it was found that surface sediment volume increased, and the density decreased from 1.36 g cm−3 to 1.13 g cm−3 with increase in accumulated CBB contents. The results of particle size distribution indicated that CBB accumulation in sediments led to sediment flocculation and agglomeration. In the meantime, there were high ratios polysaccharide/protein in extracellular polymeric substances (EPS) with a decrease in bound EPS/colloid EPS under high CBB contents, which enhanced the sediment particle agglomeration and reduced fluid sediment stability. Further, the critical shear stress in rheological test for sediments on day 30 presented an exponential decay (R2 = 0.97) with increase in accumulated CBB contents. And a threshold value at 0.15% accumulated CBB content indicated sediments could be resuspended easier when accumulated CBB content was higher than 0.15%. Altogether, this study showed that the accumulated CBB content had a strong influence on surface fluid sediment properties. The results were important in sediment management since CBB affects sediment suspension for eutrophication shallow lakes.

Boron and Lithium Isotopic Signatures of Nanometer-Sized Smectite-Rich Mixed-Layers of Bentonite Beds From Campos Basin (Brazil)

AbstractBoron and lithium were analyzed in three nanometer-sized (<20, 20-50 and 50-100 nm) separates of two Santonian (85.8-83.5 Ma) bentonite samples collected closely in the Campos Basin along the southeastern Atlantic coast (Brazil). The B and Li data give various trends that suggest varied crystallization conditions for separates that consist of overwhelming smectite with less than 9% illitic layers. The δ11B of the few illitic tetrahedral sites from one of the samples remains quite constant, while its contents are strictly correlated with those of K, which suggests that illitization proceeded by interaction with pore fluids of the host sediments that supplied the K. In the second sample, the δ11B of the illite layers from the two coarser fractions is indicative of an early volcanic origin, while the smaller size fraction also interacted with sedimentary fluids. Favored by octahedral substitutions of the smectite layers, the δ7Li is more strictly regulated by a volcanic link. In turn, the information of the B and Li isotopic compositions and contents from studied mixed-layers suggests a various origin for the few illite layers of the smectite-rich I-S that contain more B than the smectite layers that host more Li. The difference appears to be sample-site and crystal-size dependent, fueled by pore fluids of the hosting turbidites.

Microbial Survival in an Extreme Martian Analog Ecosystem: Poás Volcano, Costa Rica

Past acid-sulfate hydrothermal systems on Mars have promise in their ability to have hosted life for billions of years. One method for analyzing these systems is to study analog environments on Earth. To assess the astrobiological potential of Martian acid-sulfate hydrothermal systems, the crater lake of the active Poás Volcano, Laguna Caliente, was sampled in 2013 and 2017. Laguna Caliente presents an extremely dynamic terrestrial environment with near-ambient to boiling temperatures, pH fluctuations from −0.87 to 1.5, a wide range of chemistries and redox potential, and frequent phreatic-to-phreatomagmatic eruptions. Samples of lake fluid, sulfur clumps, and lake bottom sediment underwent 16S rRNA gene sequencing and metagenomic “shotgun” sequencing, which revealed this lake hosts an extremely low biodiversity of microorganisms dominated by Acidiphilium spp. Shotgun metagenomics of the samples suggests this community has numerous genetic adaptations that confer survival, including functional pathways to reduce the effects of toxic metals and numerous metabolic pathways utilizing a variety of simple and complex sugar molecules. The identification of these various metabolic pathways suggests adaptations related to carbon limited environments, fulfillment of high energy requirements, and survival in a hostile volcanic setting. The perseverance of life in Laguna Caliente indicates life on Mars could have thrived in analogous environments, stressing the need for the search for life in relict Martian acid-sulfate hydrothermal systems.

Response of Temperature to Biological Fluid Sediment Properties with Cyanobacterial Bloom Biomass Degradation

Response of Temperature to Biological Fluid Sediment Properties with Cyanobacterial Bloom Biomass Degradation

Chloride salt sorption flux of cohesive sediment beds with different degrees of fluidization in quiescent water

Cohesive sediments with different degrees of fluidization exhibit different rheological properties that affect chloride salt sorption in sediment and water columns. Recent studies have revealed that yield stress may be a more relevant parameter to describe the chloride salt sorption capacity of cohesive sediments at various degrees of sediment fluidization or consolidation. In this study, 365 experiments were performed to investigate the effects of sediment concentration and yield stress on chloride salt sorption flux in cohesive sediments. The results showed a negative power relationship between chloride salt sorption flux and yield stress. The chloride salt sorption flux increases with temperature, surface coefficient of fine particles, and the salinity difference between the sediment and water column. This study found that the sediment yield stress significantly affected the chloride salt sorption flux of the fluidized sediments. An empirical formula for the chloride salt sorption flux of cohesive sediment at various degrees of fluidization in quiescent water was proposed.

Mechanistic Models for USP2 Dissolution Apparatus, Including Fluid Hydrodynamics and Sedimentation

Drug product dissolution is a key input to Physiologically Based Biopharmaceutics Models (PBBM) to be able to predict in vivo dissolution. The integration of product dissolution in PBBMs for immediate release drug products should be mechanistic, i.e. allow to capture the main determinants of the in vitro dissolution experiment, and extract product batch specific parameter(s). This work focussed on the Product Particle Size Distribution (P-PSD), which was previously shown to integrate the effect of dose, volume, solubility (pH), size and concentration of micelles in the calculation of a batch specific input to PBBMs, and proposed new hydrodynamic (HD) models, which integrate the effect of USP2 apparatus paddle rotation speed and medium viscosity on dissolution. In addition, new models are also proposed to estimate the quantitative impact of formulation and drug sedimentation or “coning” on dissolution. Model “HDC-1” predicts coning in the presence of formulation insoluble excipients and “HDC-2” predicts the sedimentation of the drug substance only. These models were parameterized and validated on 166 dissolution experiments and 18 different drugs. The validation showed that the HD model average fold errors (AFE) for dissolution rate prediction of immediate release formulations, is comprised between 0.85 and 1.15, and the absolute average fold errors (AAFE) are comprised between 1.08 and 1.28, which shows satisfactory predictive power. For experiments where coning was suspected, the HDC-1 model improved the precision of the prediction (defined as ratio of “AAFE-1”values) by 2.46 fold compared to HD model. The calculation of a P-PSD integrating the impact of USP2 paddle rotation, medium viscosity and coning, will improve the PBBM predictions, since these parameters could have an influence on in vitro dissolution, and could open the way to better prediction of the effect of prandial state on human exposure, by developing new in silico tools which could integrate variation of velocity profiles due to the chyme viscosity.

An Eddy‐Resolving Numerical Model to Study Turbulent Flow, Sediment, and Bed Evolution Using Detached Eddy Simulation in a Lateral Separation Zone at the Field‐Scale

AbstractTurbulence‐resolving simulations elucidate key elements of fluid dynamics and sediment transport in fluvial environments. This research presents a feasible strategy for applying state‐of‐the‐art computational fluid mechanics to the study of sediment transport and morphodynamic processes in lateral separation zones, which are common features in canyon rivers where massive lateral flow separation causes large‐scale turbulence that controls sediment erosion and deposition. An eddy‐resolving model was developed and tested at the field‐scale, coupling a viscous flow and sediment transport solver using Detached Eddy Simulation techniques. A morphodynamic model was applied to the viscous flow/sediment solver to calculate erosion and deposition. A simulation of turbulence was performed at the grid resolution for a straight channel to determine the relative contributions of modeled and resolved diffusivity. The time‐dependent, energetically important, correlative, non‐stationary signals of the simulated quantities were captured at the lateral separation zone. Strong periodic signals featured by high amplitude were found at the separation zone, while low frequency pulsations were observed at the reattachment zone of the lateral separation zone. Interactions between the eddies and the loose bed boundaries resulted in erosion of sediment at the main channel followed by deposition at the primary eddy and eddy bars.

A self-penetration torpedo anchor with vibrational shearing

As the depths at which marine facilities are constructed increase, mooring systems have become more complex, expensive, and difficult to install, making it necessary to develop new types of anchors to replace conventional drag-type anchors. In this paper, a new anchor concept based on the application of sediment fluidization technology is proposed. The proposed self-penetration torpedo anchor has a design similar to that of a torpedo anchor but is equipped with a specially designed mechanical vibrational unit. Laboratory tests were carried out to assess the penetration behavior, holding performance, and pullout behavior of the proposed torpedo under self-induced vibration. To evaluate the effect of installation on the anchorage force, the anchoring forces were measured over different rest times following vertical arrival at designated penetration depths. It was demonstrated that the anchor is able to automatically enter deep beds at moderate penetration speeds and that it has a high holding index, with an anchoring force that can recover more than 83.2% of its holding capacity following 7 d of rest in a silty bed with median particle diameters d50 of 31 μm. Furthermore, unlike conventional torpedo anchors the anchoring force and penetration depth of the self-penetration torpedo anchor are not limited by water depth or drop height. Because the proposed torpedo can be more easily extracted through the application of vibration, problems arising from an inability to pull the anchor out can be more readily avoided.

The profile of Hip and Knee Periprosthetic Joint Infection cases at Dr. Cipto Mangunkusumo Central National Referral Hospital

Background: The most troubling complication of joint replacement procedures is periprosthetic joint infection (PJI). Pathogen identification increases the likelihood of successful treatment. The data of PJI are mostly unpublished in Indonesia. In this study we aimed to investigate the characteristics of PJI of a national hospital in Indonesia. Material and methods: This research was a cross-sectional study. The inclusion criteria were patients diagnosed with PJI confirmed by examination of fluid exudate culture, sedimentation rate and C-Reactive Protein, which was accompanied by dislocation, fracture and/or loosening of the prosthetic joint and diagnosed between January 2019 to July 2020. Result: The mean age of patients who underwent revision surgery for PJI was 50.0 ± 14.69 years-old with a slightly higher proportion of men (63.6%). Of the 21 patients, some patients had a history of surgery more than once. The clinical outcome was assessed with the Harris Hip Score (HHS) and the Visual Analog Scale (VAS). The mean HHS of all hip replacement surgeries increased from 61.4 (48.15 to 68) before surgery to 82.5 (75.7 to 84) at the 12-month follow-up post last surgery (p=0.03). Likewise, the VAS value decreased from 3 (2 to 4) before surgery to 2 (1 to 2). Conclusion: Gram positive bacteria were more prevalent compared to gram negative bacteria. The difference in the microorganism spectrum could be one of several factors. This pattern should be explored in the future by adding more samples to the study. Overall, the clinical outcome was better in both total hip and knee arthroplasty patients, measured by the Harris hip score, visual analog scale, and the knee society score

Peritoneal lavage cytology in the diagnosis of pelvic endometriosis.

We aimed to assess the sensibility, specificity, and predictive values of cytology of the fluid sediment in patients with pelvic endometriosis diagnosed based on laparoscopic-guided biopsy. Between January 2017 and September 2018, 71 specimens of peritoneal fluid collected by laparoscopy were evaluated. Fifty-three patients were diagnosed laparoscopically and histologically with endometriosis, and 18 were considered controls (without suspicious endometriosis lesions). We calculated the sensitivity, specificity, the positive and negative predictive value, and the accuracy of endometrial-like cells (ELC) and hemosiderin-laden macrophages (HLM) in the fluid sediment. Of the 50 patients with endometriosis, 32 (64%) had HLM, 9 (18%) had ELC, and 7 (14%) had both elements. Of the 18 patients without endometriosis, 3 (16%) had HLM, 2 (11%) had ELC, and 1 (5%) had both ELC and HLM. The sensitivity of the cytology of peritoneal fluid sediment for the diagnosis of endometriosis, based on the presence of ELC, was 18%, the specificity was 83%, the positive predictive value was 82%, the negative predictive value was 28.7%, and the accuracy was 36.8%. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy based on the presence of HLM were 64%, 83%, 91%, 45.5%, and 69.1%, respectively. The study of peritoneal fluids obtained laparoscopically from women undergoing evaluation for endometriosis may identify patients with the disease.