Influence of the concentrations of xanthan gum, hydroxypropyl starch and potassium chloride on the flow properties of drilling fluid formulations

Drilling operation of oil wells involves high costs and risks. With recent discoveries of deeper reservoirs and difficult to access, there was an increase in the number of horizontal wells drilled and far-reaching, and, thereat, new challenges with operational problems. Fluids, or muds, drilling are essential to the well drilling process, confirming the need to study and find physical, rheological, and filtration properties, appropriate to the complexities in each section and the drilling stage. Optimized formulation is the one that comprises a safe operation, mitigation of operational problems, environmental protection, low cost, and high productivity. Thus, this paper offers the study of the rheological properties, and determination of filtrate volume, of the aqueous base fluid formulations, developed with polymeric additives. A high performance formulation, presenting technical-economical feasibility for drilling operations, was achieved using 0.43% m/v of viscosifier (xanthan gun), 0.57% m/v of filtrate controller (hydroxypropyl starch) and 4.57% m/v of clay swelling inhibitor (KCl).La operación de perforación de pozos de petróleo implica altos costos y riesgos. Con los recientes descubrimientos de depósitos más profundos y de difícil acceso, hubo un aumento en el número de pozos horizontales perforados y de largo alcance y, por lo tanto, nuevos desafíos con problemas operacionales. Los fluidos o los lodos de perforación son esenciales para el proceso de perforación del pozo, confirmando la necesidad de estudiar y encontrar propiedades físicas, reológicas y de filtración, adecuadas a las complejidades de cada sección ya la fase de perforación. La formulación optimizada es aquella que comprende una operación segura, mitigación de problemas operacionales, protección ambiental, bajo costo y alta productividad. Así, este trabajo ofrece el estudio de las propiedades reológicas y de volumen de filtrado de las formulaciones de fluidos de base acuosa, desarrolladas con aditivos poliméricos. Una formulación de alto rendimiento, presentando viabilidad técnico-económica para operaciones de perforación, fue alcanzada utilizando 0,43% mv de viscosificante (goma xantana), 0,57% m / v de controlador de filtrado (hidroxipropilamido) y 4,57% m / v de inhibidor de la hinchazón de arcilla (KCl)

Recent Applications of the Theory of Lie Systems in Ermakov Systems

We review some recent results of the theory of Lie systems in order to apply such results to study Ermakov systems. The fundamental properties of Ermakov systems, i.e. their superposition rules, the Lewis-Ermakov invariants, etc., are found from this new perspective. We also obtain new results, such as a new superposition rule for the Pinney equation in terms of three solutions of a related Riccati equation

Bio-based synthesis of oxidation resistant copper nanowires using an aqueous plant extract

Copper nanowires have recently emerged as promising nanomaterials for transparent conducting electrodes applications, however, their production commonly involves the use of harmful reagents. In this study, we describe for the first time a simple and cost-effective bio-based synthesis of copper nanowires using an aqueous plant extract (Eucalyptus globulus) as the reducing/stabilizing agent and oleic acid and oleylamine as surfactants. Well-dispersed crystalline copper nanowires (λmáx = 584–613 nm) were obtained with average diameters in the nanometric range (44 and 145 nm) and lengths in the micrometric range (from 5 to dozens of micrometres) using extract concentrations between 10 and 50 mg mL−1. Moreover, the aspect ratio of these nanowires can be adjusted (from around 14–20 to 160–400) by changing the experimental conditions, namely the use of oleic acid. Phenolic compounds were found to have a key role in this bioreduction process allowing to obtain practically only nanowires (without other morphologies). Nevertheless, the use of oleic acid/oleylamine is essential to manipulate their size and aspect ratio. Most importantly, these bio-based copper nanowires were found to be resistant under storage in ethanol and when submitted to air exposure, both for 2 weeks, certainly due to the adsorption of antioxidant biomolecules (phenolic) at their surface, thus avoiding the use of other polymeric protective layers. The conductivity of the CuNWs was found to be 0.009 S cm−1. As a result, this study opens a new standpoint in this field, “closing the door” to the use of hazardous reagents and synthetic polymeric protective layers, on the production of stable copper nanowires with potential application as conductive materials.publishe

741phealth related quality of life hrqol in patients with early stage pancreatic cancer espc receiving adjuvant or neoadjuvant chemotherapy a nac a systematic literature review slr

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Dioctophyme renale in a domestic cat (Felis catus): Renal location and nephrectomy

Dioctophymosis is caused by Dioctophyme renale, nematode with indirect life cycle. Its intermediate host is a freshwater oligochaete and its definitive host is a wild or household carnivore. The adult nematode develops in the definite host, generally locating itself in the kidney. This article was meant to describe the first nephrectomy performed in a domestic cat due to renal dioctophymosis in Argentina. The subject showed a non-specific appearance of generally feeling ill, hematuria and mild diarrhea. It was diagnosed through abdominal ultrasound, followed by exploratory celiotomy and nephrectomy. After verifying absence of free specimens, the right kidney was removed. This organ was found to be enlarged in a spheroidal manner in contrast to the left kidney, with significant thickening of the renal capsule, excessive congestion of vessels and adhesions involving the caudal vena cava. An adult nematode was removed from the right kidney and identified as Dioctophyme renale. Reports of feline dioctophymosis are scarce being most of them necropsy findings. In this we are presenting a confirmed case of D. renale removed by surgery from a live cat. The results presented here reinforces the fact that cats are also appropriate definitive hosts for this parasite.Fil: Butti, M.J.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Microbiología. Laboratorio de Parasitosis Humanas y Zoonosis Parasitarias; ArgentinaFil: Gamboa, María Inés. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Microbiología. Laboratorio de Parasitosis Humanas y Zoonosis Parasitarias; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Terminiello, J.D.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Franchini, Gisela Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Giorello, Alejandra Nahili. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Maldonado, Lucas Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Kamenetzky, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Luna, M.F.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: López Merlo, Mariana Lucía. Universidad Nacional de la Plata. Facultad de Cs.veterinarias. Centro de Fisiologia Reproductiva y Metodos Complementarios de Diagnostico.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Radman, Nilda Ester. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Microbiología. Laboratorio de Parasitosis Humanas y Zoonosis Parasitarias; Argentin

Patrones de tomate resistentes a Meloidogyne: variabilidad de la respuesta de resistencia en función de la población del nematodo

Postprint (published version

Summarizing Patient Preferences for the Competitive Landscape of Multiple Sclerosis Treatment Options

Objective. Quantitatively summarize patient preferences for European licensed relapsing-remitting multiple scle

The Fold-in, Fold-out Design for DCE Choice Tasks: Application to Burden of Disease

Background. In discrete-choice experiments (DCEs), choice alternatives are described by attributes. The importance of each attribute can be quantified by analyzing respondents’ choices. Estimates are valid only if alternatives are defined comprehensively, but choice tasks can become too difficult for respondents if too many attributes are included. Several solutions for this dilemma have been proposed, but these have practical or theoretical drawbacks and cannot be applied in all settings. The objective of the current article is to demonstrate an alternative solution, the fold-in, fold-out approach (FiFo). We use a motivating example, the ABC Index for burden of disease in chronic obstructive pulmonary disease (COPD). Methods. Under FiFo, all attributes are part of all choice sets, but they are grouped into domains. These are either folded in (all attributes have the same level) or folded out (levels may differ). FiFo was applied to the valuation of the ABC Index, which included 15 attributes. The data were analyzed in Bayesian mixed logit regression, with additional parameters to account for increased complexity in folded-out questionnaires and potential differences in weight due to the folding status of dom

COVID-19 contact Tracing Apps: Predicted Uptake in the Netherlands Based on a Discrete Choice Experiment.

Background: Smartphone-based contact tracing apps can contribute to reducing COVID-19 transmission rates and thereby support countries emerging from lockdowns as restrictions are gradually eased. Objective: The primary objective of our study is to determine the potential uptake of a contact tracing app in the Dutch population, depending on the characteristics of the app. Methods: A discrete choice experiment was conducted in a nationally representative sample of 900 Dutch respondents. Simulated maximum likelihood methods were used to estimate population average and individual-level preferences using a mixed logit model specification. Individual-level uptake probabilities were calculated based on the individual-level preference estimates and subsequently aggregated into the sample as well as subgroup-specific contact tracing app adoption rates. Results: The predicted app adoption rates ranged from 59.3% to 65.7% for the worst and best possible contact tracing app, respectively. The most realistic contact tracing app had a predicted adoption of 64.1%. The predicted adoption rates strongly varied by age group. For example, the adoption rates of the most realistic app ranged from 45.6% to 79.4% for people in the oldest and youngest age groups (ie, ≥75 years vs 15-34 years), respectively. Educational attainment, the presence of serious underlying health conditions, and the respondents’ stance on COVID-19 infection risks were also correlated with the predicted adoption rates but to a lesser extent. Conclusions: A secure and privacy-respecting contact tracing app with the most realistic characteristics can obtain an adoption rate as high as 64% in the Netherlands. This exceeds the target uptake of 60% that has been formulated by the Dutch government. The main challenge will be to increase the uptake among older adults, who are least

The learning curve associated with the introduction of the subcutaneous implantable defibrillator

Aims: The subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced to overcome complications related to transvenous leads. Adoption of the S-ICD requires implanters to learn a new implantation technique. The aim of this study was to assess the learning curve for S-ICD implanters with respect to implant-related complications, procedure time, and inappropriate shocks (IASs). Methods and results: In a pooled cohort from two clinical S-ICD databases, the IDE Trial and the EFFORTLESS Registry, complications, IASs at 180 days follow-up and implant procedure duration were assessed. Patients were grouped in quartiles based on experience of the implanter and Kaplan-Meier estimates of complication and IAS rates were calculated. A total of 882 patients implanted in 61 centres by 107 implanters with a median of 4 implants (IQR 1,8) were analysed. There were a total of 59 patients with complications and 48 patients with IAS. The complication rate decreased significantly from 9.8% in Quartile 1 (least experience) to 5.4% in Quartile 4 (most experience) (P = 0.02) and non-significantly for IAS from 7.9 to 4.8% (P = 0.10). Multivariable analysis demonstrated a hazard ratio of 0.78 (P = 0.045) for complications and 1.01 (P = 0.958) for IAS. Dual-zone programming increased with experience of the individual implanter (P 13 implants). Conclusion: There is a short and significant learning curve associated with physicians adopting the S-ICD. Performance stab