Istodobno spektrofotometrijsko određivanje losartan kalija, amlodipin besilata i hidroklorotiazida u farmaceutskim pripravcima kemometrijskom metodom

In the present work, four different spectrophotometric methods for simultaneous estimation of losartan potassium, amlodipine besilate and hydrochlorothiazide in raw materials and in formulations are described. Overlapped data was quantitatively resolved by using chemometric methods, classical least squares (CLS), multiple linear regression (MLR), principal component regression (PCR) and partial least squares (PLS). Calibrations were constructed using the absorption data matrix corresponding to the concentration data matrix, with measurements in the range of 230.5350.4 nm (∆λ = 0.1 nm) in their zero order spectra. The linearity range was found to be 840, 15 and 315 μg ml1 for losartan potassium, amlodipine besilate and hydrochlorothiazide, respectively. The validity of the proposed methods was successfully assessed for analyses of drugs in the various prepared physical mixtures and in tablet formulations.U radu su opisane četiri spektrofotometrijske metode za istodobno određivanje losartan kalija, amlodipin besilata i hidroklorotiazida u sirovinama i farmaceutskim pripravcima. Podaci koji su se preklapali kvantitativno su razlučeni kemometrijskim metodama, klasičnom metodom najmanjih kvadrata (CLS), multiplom linearnom regresijom (MLR), regresijom glavnih komponenata (PCR) te metodom parcijalnih najmanjih kvadrata (PLS). Kalibracije su provedene koristeći podatke o ovisnosti apsorpcije o koncentracijama, mjereći spektre nultog reda u rasponu 230,5350,4 nm (∆λ = 0,1 nm). Linearnost za losartan kalij bila je 840, za amlodipin besilat 15, a za hidroklorotiazid 315 μg ml1. Valjanost predloženih metoda uspješno je potvrđena analizom navedenih lijekova u različitim pripremljenim smjesama i tabletama

Aptamer-based field-effect biosensor for tenofovir detection

During medical treatment it is critical to maintain the circulatory concentration of drugs within their therapeutic range. A novel biosensor is presented in this work to address the lack of a reliable point-of-care drug monitoring system in the market. The biosensor incorporates high selectivity and sensitivity by integrating aptamers as the recognition element and field-effect transistors as the signal transducer. The drug tenofovir was used as a model small molecule. The biointerface of the sensor is a binary self-assembled monolayer of specific thiolated aptamer and 6-mercapto-1-hexanol (MCH), whose ratio was optimized by electrochemical impedance spectroscopy measurements to enhance the sensitivity towards the specific target. Surface plasmon resonance, performed under different buffer conditions, shows optimum specific and little non-specific binding in phosphate buffered saline. The dose-response behavior of the field-effect biosensor presents a linear range between 1 nM and 100 nM of tenofovir and a limit of detection of 1.2 nM. Two non-specific drugs and one non-specific aptamer, tested as stringent control candidates, caused negligible responses. The applications were successfully extended to the detection of the drug in human serum. As demonstrated by impedance measurements, the aptamer-based sensors can be used for real-time drug monitoring

Dispersion stability and thermal conductivity of propylene glycol based nanofluids

The dispersion stability and thermal conductivity of propylene glycol-based nanofluids containing Al2O3 and TiO2 nanoparticles were studied in the temperature range of 20–80 °C. Nanofluids with different concentrations of nanoparticles were formulated by the two-step method and no dispersant was used. In contrast to the common belief, the average particle size of nanofluids was observed to decrease with increasing temperature, and nanofluids showed an excellent stability over the temperature range of interest. Thermal conductivity enhancement for both studied nanofluids was a nonlinear function of concentration and was temperature independent. Theoretical analyses were also performed using existing models compared with experimental results. The model based on the aggregation theory appears to be the best

Advanced materials for geothermal energy applications

Usage of advanced materials and tools in geothermal energy applications become a trendy topic that captures a glance in the industry day by day. New technology materials such as fiber coatings, dressing materials and composites as well as new technology tools such as Distributed Temperature Sensing Systems and Distributed Thermal Perturbation Sensor allows an improved reservoir monitoring in harsh environments that have HTHP or high CO2 conditions. Thermal Infrared Remote Sensing tools that could be attached to a carrier like an aircraft, drone or a satellite and enables to describe temperature anomalies in forests, seabed, and land also pave the way of a robust identification of geothermal sources and hot spring waters. Tracers determine hydraulic connectivity between wells an gives an idea about the reservoir volume. Advanced drilling fluids are advantageous due to their light weight, tough structure which resists to corrosion compared with conventional ones and the developments promising to evolve these fluids with nanotechnology in close future. Advanced cements that developed by the aim of providing perfect zonal isolation opened the way of developing various cement types such as; foam cements, phosphate bonded, self-healing, and CO2 resistant cements. Apart from exploration phase, many inventions and developments that ensures lower health and safety risks, lower operating and maintenance costs and increases the energy efficiency in heat transfer and energy conversion sections of geothermal industry were gained a place in the market.In this chapter of the book, latest advances in geothermal industry materials and applications as well as latest technology tools which are more beneficial and efficient compared with the conventional methods are investigated in details. © 2021 Elsevier Inc. All rights reserved

Optimization of micellar-polymer drive in a stochastic reservoir [??????????? ???????????-??????????? ?????????? ??? ??????????????? ? ?????????????? ??????? ???????]

SPE Russian Petroleum Technology Conference 2019, RPTC 2019 -- 22 October 2019 through 24 October 2019 -- -- 1570612-s2.0-85084166560Micellar - Polymer drive process is one of the effective, proven and widely used non-thermal EOR methods which classified under chemical flooding. The process is preferable in reservoirs that don't have enough aquifer assistance and also in depleted reservoirs. A successful micellar-polymer flooding operation can be enabled by having correct data of parameters like reservoir pressure, mineral types in the reservoir, phase behavior of microemulsions, reservoir temperature, salinity data, buffer stability, micellar slug, and concentrations of the surfactants. In this study, A comprehensive literature review regarding on above parameters studied with field case studies worldwide. A Micellar- polymer drive process is applied on a stochastic reservoir and the optimization of the case performed by considering the mechanisms and limitations of micellar-polymer drive process, selection and design criteria, as well as the phase behavior changes during the process to have the most effective residual oil recovery. Parameters that enables an optimal recovery is described and used as optimization parameters in a full-physics commercial reservoir simulator. Typical Injection sequence that includes water flooding, polymer injection, polymer drive, polymer taper and chase water is applied for selected time periods. Changes of Oil saturation, water viscosity, adsorbed fluid, surfactant and polymer adsorption is simulated by using the optimal values of selected optimization parameters. General solution results are given with the optimal solution and all compared with the base case. It clarified that the Micellar-polymer drive optimization maximizes cumulative oil recovery in a reservoir that has a stochastically generated permeability distribution. © 2019, Society of Petroleum Engineer

Using spray-dried microalgae in ice cream formulation as a natural colorant: Effect on physicochemical and functional properties

2-s2.0-85078801331Microalgae can potentially be used as a food ingredient due to its biochemical composition that can enrich the bioactive compound content of the food products. In the present study, spray-dried Nannochloropsis oculata, Porphyridium cruentum and Diacronema vlkianum microalgae species were added to ice cream formulation at different concentrations (0.10, 0.20 and 0.30 g 100 g? 1). The effect of microalgae usage on the color, melting, sensory, flow behaviour and functional properties of ice creams was investigated. Ostwal de Waele model described the flow behaviour of the ice cream mixes well and the consistency index increased with P. cruentum biomass concentration, whereas this value decreased by using N. oculata and D. vlkianum biomasses. Generally, the color of ice creams was remarkably affected by both microalgae type and concentration, and N. oculata and D. vlkianum species had a more pronounced effect. Regarding sensory characteristics, ice cream samples produced with P. cruentum were preferred more than the other samples. The phenolic contents of the ice cream samples increased with microalgae usage. It can be concluded that microalgae can be used in ice cream to improve color and functional properties; however, usage level should be optimized carefully to overcome disadvantages of the microalgae in terms of sensory characteristics. © 2020 Elsevier B.V.Ege ÜniversitesiThe authors thank Ege University; Fisheries Faculty, where culture of algae have been carried out. The authors would like to thank the technical staff at the Yildiz Technical University; Food Engineering Department Laboratory for some analyses of ice-cream

Does Sugammadex Administration Affect Postoperative Nausea and Vomiting After Laparoscopic Cholecystectomy: A Prospective, Double-Blind, Randomized Study

PMID = 2873195

Using encapsulated Nannochloropsis oculata in white chocolate as coloring agent

2-s2.0-85088562883Colored chocolate products have gained importance in recent years. This increases the importance of identifying potential natural colorants for chocolate technology. In this study, Nannochloropsis oculata microalgae which were grown by using tubular photobioreactor in two different forms (spray-dried and encapsulated by using a spray dryer and maltodextrin (50%)), were used in white chocolate composition (0.00–0.75 g) as a coloring agent. The color stability (?E) values for all sample groups were determined below the visibility level of 3.0 under accelerated shelf life conditions (25 °C/70% RH) for 28 days. The water activity, moisture and ash content, hardness, yield stress, plastic viscosity, and melting properties of white chocolate samples showed no significant differences (P > 0.05) and the other quality characteristics were found to be acceptable. The chlorophyll-a content of white chocolate samples was between 9.60–22.9 ?g g?1. It was found that the sensory properties of the samples as appearance, texture, melting in the mouth, and odor were not affected by level of microalgae use (P > 0.05). However, it was noteworthy that there was a decrease in taste and overall acceptability according to usage level of dried and encapsulated microalgae (P < 0.05). As a result, it was determined that spray-drying technique is preferred for use of microalgae in chocolate composition. © 2020, Springer Nature B.V.Ege ÜniversitesiThe authors thank Ege University, Fisheries Faculty, where culture of algae has been carried out. The authors would like to thank the technical staff at the Yildiz Technical University and Tayas Food, R&D Department, for some analyses of white chocolate