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Computational fluid dynamics (CFD) simulations are widely used to develop and analyze blood-contacting medical devices such as left ventricular assist devices (LVADs). This work presents an analysis of the transient behavior of two centrifugal LVADs with different designs: HeartWare VAD and HeartMate3. A scale-resolving methodology is followed through Large Eddy Simulations, which allows for the visualization of turbulent structures. The three-dimensional (3D) LVAD models are coupled to a zero-dimensional (0D) 2-element Windkessel model, which accounts for the vascular resistance and compliance of the arterial system downstream of the device. Furthermore, both continuous- and pulsatile-flow operation modes are analyzed. For the pulsatile conditions, the artificial pulse of HeartMate3 is imposed, leading to a larger variation of performance variables in HeartWare VAD than in HeartMate3. Moreover, CFD results of pulsatile-flow simulations are compared to those obtained by accessing the quasi-steady maps of the pumps. The quasi-steady approach is a predictive tool used to provide a preliminary approximation of the pulsatile evolution of flow rate, pressure head, and power, by only imposing a speed pulse and vascular parameters. This preliminary quasi-steady solution can be useful for deciding the characteristics of the pulsatile speed law before running a transient CFD simulation, as the former entails a significant reduction in computational cost in comparison to the latter.
Subject(s)
Heart-Assist Devices , Hydrodynamics , Pulsatile Flow , Models, Cardiovascular , Computer Simulation , Centrifugation , HumansABSTRACT
The northwest-southeast convergence of the Eurasian and Nubian (African) plates in the western Mediterranean region propagates inside the Nubian plate and affects the Moroccan Meseta and the neighboring Atlasic belt. Five continuous Global Positioning System (cGPS) stations were installed in this area in 2009 and provide significant new data, despite a certain degree of errors (between 0.5 and 1.2 mm year-1, 95% confidence) due to slow rates. The cGPS network reveals 1 mm year-1 North/South shortening accommodated within the High Atlas Mountains, and unexpected 2 mm year-1 north-northwest/south-southeast extensional-to-transtensional tectonics within the Meseta and the Middle Atlas, which have been quantified for the first time. Moreover, the Alpine Rif Cordillera drifts towards the south-southeast against its Prerifian foreland basins and the Meseta. In this context, the geological extension foreseen in the Moroccan Meseta and Middle Atlas agrees with a crustal thinning due to the combined effect of the anomalous mantle beneath both the Meseta and Middle-High Atlasic system, from which Quaternary basalts were sourced, and the roll-back tectonics in the Rif Cordillera. Overall, the new cGPS data provide reliable support for understanding the geodynamic mechanism that built the prominent Atlasic Cordillera, and reveal the heterogeneous present-day behavior of the Eurasia-Nubia collisional boundary.
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Cancer is first a localized tissue disorder, whose soluble and exosomal molecules and invasive cells induce a host response providing the stromal components of the primary tumor microenvironment (TME). Once the TME is developed, cancer-derived molecules and cells can more efficiently spread out and a whole-body response takes place, whose pathophysiological changes may result in a paraneoplastic syndrome. Remote organ-specific prometastatic reactions may also occur at this time, facilitating metastatic activities of circulating tumor cells (CTCs) through premetastatic niche development at targeted organs. However, additional signaling factors from the inter-organ communication network involved in the pathophysiology and comorbidities of cancer patients may also regulate prometastatic reaction-stimulating effects of cancer and non-cancer tissue factors. This article provides a conceptual overview of our ongoing clinical research on the liver prometastatic reaction (LPR) of patients with colorectal cancer (CRC), their portal vein- and hepatic artery-driven LPR-Stimulating Factors (LPR-SF), and their resulting LPR-derived Metastasis-Stimulating Factors (LPR-MSF) acting on liver-invading CRC cells. In addition, we also provide new insights on the molecular subtyping of LPR-responsive cancer phenotypes in patients with CRC and melanoma; and on how to investigate and interpret the prometastatic infrastructure in the real pathophysiological context of patients with cancer undergoing surgical procedures and receiving pharmacological treatments with multiple side effects, including those affecting the LPR, its stimulating factors and responsive cancer phenotypes.
Subject(s)
Liver Neoplasms/secondary , Neoplasm Recurrence, Local/pathology , Neoplastic Cells, Circulating/pathology , Phenotype , Tumor Microenvironment , Animals , HumansABSTRACT
The Gibraltar Arc includes the Betic and Rif Cordilleras surrounding the Alboran Sea; it is formed at the northwest-southeast Eurasia-Nubia convergent plate boundary in the westernmost Mediterranean. Since 2006, the Campo de Dalias GNSS network has monitored active tectonic deformation of the most seismically active area on the north coast of the Alboran Sea. Our results show that the residual deformation rates with respect to Eurasia range from 1.7 to 3.0 mm/year; roughly homogenous west-southwestward displacements of the northern sites occur, while the southern sites evidence irregular displacements towards the west and northwest. This deformation pattern supports simultaneous east-northeast-west-southwest extension, accommodated by normal and oblique faults, and north-northwest-south-southeast shortening that develops east-northeast-west-southwest folds. Moreover, the GNSS results point to dextral creep of the main northwest-southeast Balanegra Fault. These GNNS results thus reveal, for the first time, present-day interaction of the roll-back tectonics of the Rif-Gibraltar-Betic slab in the western part of the Gibraltar Arc with the indentation tectonics affecting the eastern and southern areas, providing new insights for improving tectonic models of arcuate orogens.
Subject(s)
Moths , Animals , GibraltarABSTRACT
GNSS observations constitute the main tool to reveal Earth's crustal deformations in order to improve the identification of geological hazards. The Ecuadorian Andes were formed by Nazca Plate subduction below the Pacific margin of the South American Plate. Active tectonic-related deformation continues to present, and it is constrained by 135 GPS stations of the RENAGE and REGME deployed by the IGM in Ecuador (1995.4-2011.0). They show a regional ENE displacement, increasing towards the N, of the deformed North Andean Sliver in respect to the South American Plate and Inca Sliver relatively stable areas. The heterogeneous displacements towards the NNE of the North Andean Sliver are interpreted as consequences of the coupling of the Carnegie Ridge in the subduction zone. The Dolores-Guayaquil megashear constitutes its southeastern boundary and includes the dextral to normal transfer Pallatanga fault, that develops the Guayaquil Gulf. This fault extends northeastward along the central part of the Cordillera Real, in relay with the reverse dextral Cosanga-Chingual fault and finally followed by the reverse dextral Sub-Andean fault zone. While the Ecuadorian margin and Andes is affected by ENE-WSW shortening, the easternmost Manabí Basin located in between the Cordillera Costanera and the Cordillera Occidental of the Andes, underwent moderate ENE-WSW extension and constitutes an active fore-arc basin of the Nazca plate subduction. The integration of the GPS and seismic data evidences that highest rates of deformation and the highest tectonic hazards in Ecuador are linked: to the subduction zone located in the coastal area; to the Pallatanga transfer fault; and to the Eastern Andes Sub-Andean faults.
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OBJECTIVE: The aim of the study was to estimate human papillomavirus (HPV) vaccination efficacy in reducing recurrence risk within 4 years after conization for high-grade cervical neoplasia. MATERIALS AND METHODS: From January 2012 to June 2015, we performed a longitudinal, observational study (case-series study) on patients diagnosed with cervical intraepithelial neoplasia 2-3 neoplasia. Efficacy was estimated by a 95% CI of the relative risk, relative risk reduction, attributable risk, and number needed to treat. Parametric and nonparametric tests were used as appropriate to compare 160 vaccinated with 171 nonvaccinated patients. To estimate the hazard ratio of the vaccinated status, patients were subjected to multivariable analyses based on the Cox proportional hazard model. To compare recurrence-free survival, a Kaplan-Meier model and a log-rank test were applied. RESULTS: The overall recurrence was 9.4% in the nonvaccinated and 2.5% in the vaccinated group (p = .009). Vaccination was associated with a significant decrease in the relative risk (73.5%, 95% CI = 21.8%-90.9%) with a mean number needed to treat of 14 patients per relapse prevented. Although positive conization margins were related to the highest recurrence risk, not being vaccinated independently increased this risk 3.5-fold in a 4-year follow-up (p = .025). Cumulative recurrence-free rates differed significantly between both groups (log-rank test: p = .009). CONCLUSIONS: Our study corroborates the benefits of HPV vaccination, recommends a closer and longer follow-up in nonvaccinated women, and offers a 4-year prognosis for patients undergoing conization for high-grade cervical lesions.
Subject(s)
Alphapapillomavirus , Papillomavirus Infections , Papillomavirus Vaccines , Uterine Cervical Neoplasms , Conization , Female , Gammapapillomavirus , Humans , Neoplasm Recurrence, Local , Papillomavirus Infections/complications , Papillomavirus Infections/prevention & control , Uterine Cervical Neoplasms/prevention & control , Uterine Cervical Neoplasms/surgery , VaccinationABSTRACT
BACKGROUND: The current therapies for hepatic encephalopathy (HE) are not completely effective in all patients, probably due to the physiopathological heterogeneity and the different conditions underlying the bout of HE. We hypothesized that oral glutamine challenge (OGC) is able to predict the risk of HE through the identification of various features and types of HE. METHODS: We included 238 cirrhotic patients (198 without and 40 with a previous HE episode) that underwent OGC, obtaining baseline and 60 minutes post-load ammonia levels. Combined evaluation of baseline hyperammonemia (>78 mcg/dL) and impaired OGC (Δ >32 mcg/dL) defined low-, intermediate- and high-risk groups. Patients were censored at HE, liver transplantation and death or 6 years of follow-up. RESULTS: The 28.3% (56/198) of the main cohort suffered from HE during the follow-up. In the competing risk analysis, both intermediate- (subhazard ratio (sHR) 2.01 (95% CI 1.00-4.14); P = .048) and high-risk groups (sHR 4.67 (95% CI 2.19-9.98); P = .0001) were associated with the first HE episode, together with age and albumin. Similar results were found for repeated HE events. The cumulative incidence for HE of the high-risk group was two and four times greater than the intermediate- and low-risk groups, respectively. The HE grade was also higher in individuals with the greatest risk (P = .035). The most common precipitant factor was diuretics in the high-risk group, while infections and electrolyte imbalance predominated in the rest of patients. CONCLUSION: Oral glutamine challenge identified patients at risk of HE and defined specific features of the episodes. This tool could be useful in the decision-making process for the adequate management of HE.
Subject(s)
Ammonia , Hepatic Encephalopathy , Administration, Oral , Glutamine/therapeutic use , Hepatic Encephalopathy/drug therapy , Humans , Liver Cirrhosis/complications , Liver Cirrhosis/drug therapyABSTRACT
INTRODUCTION AND OBJECTIVE: This study aims to evaluate safety and efficacy of different endoscopic enucleation of the prostate (EEP) techniques, by comparing laser (L-EEP) and non-laser (NL-EEP) procedures; and EEP versus other endoscopic non-enucleation (ENE) surgeries for benign prostatic enlargement (BPE). METHODS: A systematic literature review was performed for randomized clinical trials (RCT) that compared different endoscopic treatments for BPE, between 1982 and 2018. Two analyses were performed: (1) EEP versus ENE; and (2) L-EEP versus NL-EEP. Efficacy was assessed using perioperative data (removed tissue volume, operation time (OT), catheterization time, length of hospital stay); and functional outcomes [IPSS, IIEF-5, maximum flow rate (Qmax), postvoid residual volume (PVR), quality of life (QoL)]. Safety was assessed through complications (Hb and sodium decrease, transfusion rate). Meta-analyses were performed using RevMan® 5.3. RESULTS: Out of 35 RCTs (4066 patients), 31 (3909 patients) evaluated EEP versus ENE, and 4 (327 patients) evaluated L-EEP versus NL-EEP. EEP presented greater Qmax. Also, EEP presented less catheterization time, length of hospital stay, Hb decrease, transfusion rate. OT and bladder injury were greater with EEP. There were no significant differences between other items. L-EEP removed more tissue volume, with a smaller drop in serum Hb. There were no significant differences in other perioperative data, functional outcomes, complications. CONCLUSIONS: EEP and ENE are effective and safe for treating BPE. Perioperative data favors EEP. Statistical differences, with questionable clinical significance in functional outcomes and complication rates were encountered. L-EEP provides greater tissue removal and smaller Hb decrease then NL-EEP, with similar functional profiles.
Subject(s)
Endoscopy , Prostatectomy/methods , Prostatic Hyperplasia/surgery , Endoscopy/adverse effects , Humans , Male , Prostatectomy/adverse effects , Randomized Controlled Trials as Topic , Treatment OutcomeABSTRACT
The Thomas equation is a popular model that has been widely used to predict breakthrough curves (BTCs) when describing the dynamic adsorption of different pollutants in a fixed-bed column system. However, BTCs commonly exhibit unsymmetrical patterns that cannot be predicted using empirical equations such as the Thomas model. Fortunately, adaptive neural-based fuzzy inference systems (ANFISs) can be used to model complex patterns found in adsorption processes in a fixed-bed column system. Consequently, a new hybrid model merging Thomas and an ANFIS was introduced to estimate the performance of BTCs, which were obtained for Cd(II) ion adsorption on ostrich bone ash-supported nanoscale zero-valent iron (nZVI). The results obtained showed that the fair performance of the Thomas model (NRMSE = 27.6% and Ef = 64.6%) improved to excellent (NRMSE = 3.8% and Ef = 93.8%) due to the unique strength of ANFISs in nonlinear modeling. The sensitivity analysis indicated that the initial solution pH was a more significant input variable influencing the hybrid model than the other operational factors. This approach proves the potential of this hybrid method to predict BTCs for the dynamic adsorption of Cd(II) ions by ostrich bone ash-supported nZVI particles.
Subject(s)
Models, Chemical , Water Pollutants, Chemical/analysis , Adsorption , Fuzzy Logic , Ions , IronABSTRACT
The aim of this paper is to study the behavior of an earth fill dam, analyzing the deformations determined by high precision geodetic techniques and those obtained by the Finite Element Method (FEM). A large number of control points were established around the area of the dam, and the measurements of their displacements took place during several periods. In this study, high-precision leveling and GNSS (Global Navigation Satellite System) techniques were used to monitor vertical and horizontal displacements respectively. Seven surveys were carried out: February and July 2008, March and July 2013, August 2014, September 2015 and September 2016. Deformations were predicted, taking into account the general characteristics of an earth fill dam. A comparative evaluation of the results derived from predicted (FEM) and observed deformations shows the differences on average being 20 cm for vertical displacements, and 6 cm for horizontal displacements at the crest. These differences are probably due to the simplifications assumed during the FEM modeling process: critical sections are considered homogeneous along their longitude, and the properties of the materials were established according to the general characteristics of an earth fill dam. These characteristics were taken from the normative and similar studies in the country. This could also be due to the geodetic control points being anchored in the superficial layer of the slope when the construction of the dam was finished.
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OBJECTIVES: The objectives of this study are to examine the efficacy and safety of low-dose aspirin (LDA) vs LDA plus low-intensity warfarin (LDA + W) in the primary thrombosis prevention of aPL-positive patients with SLE and/or obstetric morbidity and the role of clinical and serological markers in the development of thrombosis. METHODS: In this 5-year prospective, randomized, open, controlled trial, 166 patients with aPL were randomly assigned using a minimization protocol to receive treatment with LDA (n = 82) or LDA + W [international normalized ratio (INR) = 1.5] (n = 84). Sixty-six patients who declined randomization were followed up in an observational arm. Clinical and laboratory characteristics and medication side effects were recorded. RESULTS: There were no differences in the number of thromboses between patients treated with LDA (4/82) or LDA + W (4/84) [hazard ratio (HR) 1.07, 95% CI 0.27, 4.3]. The incidence of thrombosis in the randomized patients was 8/166 (1.8 events/100 person-years) (HR 1.07, 95% CI 0.27, 4.3) and in the observational arm was 7/66 (4.9 events/100 person-years) (HR 2.43, 95% CI 0.87, 6.79). Sixty-five of 66 patients included in the observational arm received LDA. None of the examined clinical or serological factors appeared to predict thrombosis. Medication side effects included mild gastrointestinal symptoms in the LDA group (n = 2) and bleeding in the LDA + W group (n = 11; 1 nasal and 10 menorrhagia). The risk difference for bleeding was 13% (CI 6, 20). CONCLUSION: No differences in the number of thromboses were observed between patients treated with LDA vs those treated with LDA + W. More episodes of bleeding were detected in the LDA + W group. The LDA + W regime was significantly less safe and not as acceptable as LDA alone. TRIAL REGISTRATION: ISRCTN81818945; http://isrctn.org/.
Subject(s)
Antibodies, Antiphospholipid/blood , Anticoagulants/therapeutic use , Aspirin/therapeutic use , Autoimmune Diseases/immunology , Pregnancy Complications/immunology , Thrombosis/prevention & control , Warfarin/therapeutic use , Adult , Antibodies, Antiphospholipid/immunology , Anticoagulants/administration & dosage , Antiphospholipid Syndrome/blood , Antiphospholipid Syndrome/complications , Antiphospholipid Syndrome/immunology , Aspirin/administration & dosage , Autoimmune Diseases/blood , Autoimmune Diseases/complications , Dose-Response Relationship, Drug , Drug Therapy, Combination , Female , Follow-Up Studies , Humans , Kaplan-Meier Estimate , Longitudinal Studies , Lupus Erythematosus, Systemic/blood , Lupus Erythematosus, Systemic/complications , Lupus Erythematosus, Systemic/immunology , Male , Middle Aged , Outcome Assessment, Health Care , Pregnancy , Pregnancy Complications/blood , Prospective Studies , Thrombosis/immunology , Treatment Outcome , Warfarin/administration & dosageABSTRACT
The diffusion-driven Turing instability is a potential mechanism for spatial pattern formation in numerous biological and chemical systems. However, engineering these patterns and demonstrating that they are produced by this mechanism is challenging. To address this, we aim to solve the inverse problem in artificial and experimental Turing patterns. This task is challenging since patterns are often corrupted by noise and slight changes in initial conditions can lead to different patterns. We used both least squares to explore the problem and physics-informed neural networks to build a noise-robust method. We elucidate the functionality of our network in scenarios mimicking biological noise levels and showcase its application using an experimentally obtained chemical pattern. The findings reveal the significant promise of machine learning in steering the creation of synthetic patterns in bioengineering, thereby advancing our grasp of morphological intricacies within biological systems while acknowledging existing limitations.
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BACKGROUND: Iatrogenic bile duct injury (BDI) during cholecystectomy is associated with a complex and heterogeneous management owing to the burden of morbidity until their definitive treatment. This study aimed to define the textbook outcomes (TOs) after BDI with the purpose to indicate the ideal treatment and to improve it management. METHODS: We collected data from patients with an BDI between 1990 and 2022 from 27 hospitals. TO was defined as a successful conservative treatment of the iatrogenic BDI or only minor complications after BDI or patients in whom the first repair resolves the iatrogenic BDI without complications or with minor complications. RESULTS: We included 808 patients and a total of 394 patients (46.9%) achieved TO. Overall complications in TO and non-TO groups were 11.9% and 86%, respectively (P < .001). Major complications and mortality in the non-TO group were 57.4% and 9.2%, respectively. The use of end-to-end bile duct anastomosis repair was higher in the non-TO group (23.1 vs 7.8, P < .001). Factors associated with achieving a TO were injury in a specialized center (adjusted odds ratio [aOR], 4.01; 95% CI, 2.68-5.99; P < .001), transfer for a first repair (aOR, 5.72; 95% CI, 3.51-9.34; P < .001), conservative management (aOR, 5.00; 95% CI, 1.63-15.36; P = .005), or surgical management (aOR, 2.45; 95% CI, 1.50-4.00; P < .001). CONCLUSION: TO largely depends on where the BDI is managed and the type of injury. It allows hepatobiliary centers to identify domains of improvement of perioperative management of patients with BDI.
Subject(s)
Bile Ducts , Iatrogenic Disease , Intraoperative Complications , Humans , Male , Female , Bile Ducts/injuries , Bile Ducts/surgery , Middle Aged , Intraoperative Complications/etiology , Aged , Retrospective Studies , Cholecystectomy/adverse effects , Adult , Anastomosis, Surgical , Cholecystectomy, Laparoscopic/adverse effects , Treatment Outcome , Postoperative Complications/etiology , Postoperative Complications/epidemiology , Conservative TreatmentABSTRACT
Mechanical circulatory support using ventricular assist devices is a common technique for treating patients suffering from advanced heart failure. The latest generation of devices is characterized by centrifugal turbopumps which employ magnetic levitation bearings to ensure a gap clearance between moving and static parts. Despite the increasing use of these devices as a destination therapy, several long-term complications still exist regarding their hemocompatibility. The blood damage associated with different pump designs has been investigated profoundly in the literature, while the hemodynamic performance has been hardly considered. This work presents a novel comparison between the two main devices of the latest generation-HVAD and HM3-from both perspectives, hemodynamic performance and blood damage. Computational fluid dynamics simulations are performed to model the considered LVADs, and computational results are compared to experimental measurements of pressure head to validate the model. Enhanced performance and hemocompatibility are detected for HM3 owing to its design incorporating more conventional blades and larger gap clearances.
Subject(s)
Heart Failure , Heart-Assist Devices , Humans , Hemodynamics , Magnetics , HemolysisABSTRACT
OBJECTIVE: Our objective is the description of the technique of vagus nerve stimulation in carotid triangle in order to monitor the recurrent laryngeal nerve (RLN) during thyroid and parathyroid surgery. METHODS: We stimulated the vagus nerve in the carotid triangle during 150 thyroid or parathyroid surgeries using a monopolar electromyography electrode inserted under the mastoid process towards the jugular foramen as a cathode, and using another subdermal electrode in the mastoid as an anode. Another complementary method of vagus stimulation was achieved with a pair of subdermal electrodes, placing the cathode at the mandibular angle and the anode at the mastoid. RESULTS: In all patients, compound muscle action potential (CMAP) was recorded in the vocal cords with both stimulation techniques, allowing semi-continuous monitoring to be carried out. Intraoperative lesions were detected in 16 of the cases; 9 of them were transient with CMAP recovery achieved when modifying surgical maneuvers. CONCLUSIONS: Vagus nerve stimulation in the carotid triangle is a reliable technique for monitoring the RLN in thyroid surgery. Vagus nerve stimulation in the carotid triangle is effective and safe for RLN monitoring, and it is a clear alternative to direct continuous stimulation of the nerve that by contrast requires its dissection in the carotid sheath.
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BACKGROUND AND OBJECTIVE: Frank's sign is the diagonal ear fold which has been associated with ischemic heart disease. The objective of this work was to evaluate the relationship of Frank's sign with severity of ischemic heart disease in adults ≤ 65 years old in the northeast of Mexico. PATIENTS AND METHODS: A cross-sectional study was conducted in patients ≤ 65 years old who underwent coronary angiography consecutively over a period of 5 months in 2022. Severe coronary artery disease (CAD) was associated with Frank's sign and other common cardiovascular risks. To determine the association, bivariate and multivariate analysis was performed using logistic regression that included variables with a value of p<0.05. Statistical analysis was performed with SPSS version 22. RESULTS: We included 311 patients ≤ 65 years, of whom 80% were men. The median age was 57 years (range 28-65). Frank's sign was positive in 62% of the population. The main clinical characteristics in patients with Frank's sign were type 2 diabetes mellitus (55%), p=0.003, dyslipidemia (53%), p=0.026 and smoking (68%), p=0.002. In the multivariate analysis, the independent variables associated with severe CAD were Frank's Sign OR 3.26; 95% CI (1.98-5.38), p≤0.001, male gender OR 2.28; 95% CI (1.20-4.35), p=0.012, and dyslipidemia OR 1.81; 95% CI (1.11-2.97), p=0.017. CONCLUSIONS: There is an independent association between Frank's sign with the presence of severe CAD in patients ≤ 65 years old, which may be useful for screening and prevention.
Subject(s)
Coronary Artery Disease , Diabetes Mellitus, Type 2 , Dyslipidemias , Adult , Humans , Male , Middle Aged , Aged , Female , Ear, External , Diabetes Mellitus, Type 2/complications , Cross-Sectional Studies , Coronary Artery Disease/diagnosis , Coronary Artery Disease/diagnostic imaging , Dyslipidemias/complicationsABSTRACT
Lanthanum aluminate-based perovskite (LaAlO3) has excellent stability at high temperatures, low toxicity, and high chemical resistance and also offers wide versatility to the substitution of La3+ and Al3+, thus, allowing it to be applied as a catalyst, nano-adsorbent, sensor, and microwave dielectric resonator, amongst other equally important uses. As such, LaAlO3 perovskites have gained importance in recent years. This review considers the extensive literature of the past 10 years on the synthesis and catalytic applications of perovskites based on lanthanum and aluminum (LaAlO3). The aim is, first, to provide an overview of the structure, properties, and classification of perovskites. Secondly, the most recent advances in synthetic methods, such as solid-state methods, solution-mediated methods (co-precipitation, sol-gel, and Pechini synthesis), thermal treatments (combustion, microwave, and freeze drying), and hydrothermal and solvothermal methods, are also discussed. The most recent energetic catalytic applications (the dry and steam reforming of methane; steam reforming of toluene, glycerol, and ethanol; and oxidative coupling of methane, amongst others) using these functional materials are also addressed. Finally, the synthetic challenges, advantages, and limitations associated with the preparation methods and catalytic applications are discussed.
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The aim of this study is to optimize the adsorption of pentachlorophenol (PCP) using an organo-clay under the response surface methodology. The adsorbent was selected from a montmorillonite exchanged by various cations, such as Fe3+, Al3+, Zn2+, Mg2+, Na+, and modified by bromide cetyltrimethylammonium (CTAB) as surfactant. The obtained organo-montmorillonite was characterized using several techniques, such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and nitrogen adsorption, performed at -196 °C. The results showed an increase in basal space from 1.65 to 1.88 nm and a decrease in the specific surface and pore volume, with an increase in pore diameter, including the presence of characteristic bands of -CH2- and -CH3- groups at 2926 and 2854 cm-1 in the FTIR spectrum after the modification. The optimization of PCP removal by clay adsorbents is achieved using the response surface methodology (RSM) with a four-factor central composite model, including pH of solution, mass of adsorbent, contact time, and initial concentration. The results proved the validity of the regression model, wherein the adsorption capacity reaches its maximum value of 38 mg/g at a lower adsorbent mass of 20 mg, pH of 6, contact time (tc) of 5 h, and initial concentration of 8 mg/L.
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Mechanical circulatory support using ventricular assist devices has become commonplace in the treatment of patients suffering from advanced stages of heart failure. While blood damage generated by these devices has been evaluated in depth, their hemodynamic performance has been investigated much less. This work presents the analysis of the complete operating map of a left ventricular assist device, in terms of pressure head, power and efficiency. Further investigation into its hemocompatibility is included as well. To achieve these objectives, computational fluid dynamics simulations of a centrifugal blood pump with a wide-blade impeller were performed. Several conditions were considered by varying the rotational speed and volumetric flow rate. Regarding the device's hemocompatibility, blood damage was evaluated by means of the hemolysis index. By relating the hemocompatibility of the device to its hemodynamic performance, the results have demonstrated that the highest hemolysis occurs at low flow rates, corresponding to operating conditions of low efficiency. Both performance and hemocompatibility are affected by the gap clearance. An innovative investigation into the influence of this design parameter has yielded decreased efficiencies and increased hemolysis as the gap clearance is reduced. As a further novelty, pump operating maps were non-dimensionalized to highlight the influence of Reynolds number, which allows their application to any working condition. The pump's operating range places it in the transitional regime between laminar and turbulent, leading to enhanced efficiency for the highest Reynolds number.
Subject(s)
Heart Failure , Heart-Assist Devices , Equipment Design , Hemodynamics , Hemolysis , HumansABSTRACT
BACKGROUND: NAFLD clinical trials have shown suboptimal results, particularly for liver fibrosis, despite the robust preclinical drug development. We aimed to assess the histological response after the experimental treatment versus placebo by carrying out a meta-analysis of NAFLD clinical trials. METHODS: After a systematic review of NAFLD clinical trials to May 2021, applying strict selection criteria, the following primary outcomes were observed: (a) NASH resolution, with no worsening of fibrosis when available; (b) fibrosis improvement ≥ 1 stage, with no worsening of NAS when available; (c) worsening of NAS; (d) worsening of liver fibrosis ≥ 1 stage, including the progression to cirrhosis on histopathology. Other histological, clinical, and biochemical outcomes were considered secondary endpoints. Heterogeneity was explored by subgroup and sensitivity analyses, and univariable meta-regression. RESULTS: Twenty-seven randomized clinical trials were included. The pooled efficacy for NASH resolution receiving experimental therapy was 19% (95%CI 15-23; I2 96.2%) compared with placebo 10% (95%CI 7-12; I2 85.8%) (OR 1.66 (95%CI 1.24-2.21); I2 57.8%), while it was 26% (95%CI 22-29); I2 90%)) versus 18% (95%CI 15-21; I2 59%)) for fibrosis improvement (OR 1.34 (95%CI 1.13-1.58); I2 25.4%). For these outcomes, the therapy showed higher efficacy in trials longer than 48 weeks, with < 60% of diabetic population, and when it targeted FXR, PPAR, and antidiabetic mechanisms, and with a NAS < 5 for NASH resolution. Also, NASH (OR 0.57 (95%CI 0.39-0.84); I2 67%) and fibrosis worsening (OR 0.65 (95%CI 0.46-0.92); I2 61.9%) were prevented with the therapy. CONCLUSION: This meta-analysis provides information about the efficacy of the therapy versus placebo by comparing different and combined trial outcomes such as NASH resolution, fibrosis improvement, and NAS and fibrosis worsening. Changes in the experimental design and selection criteria of the clinical trials might be suitable to increase the efficacy.