Search
Filters
total: 1553
filtered: 1385
displaying 1000 best results Help
Search results for: reversed phase high-pressure liquid chromatography (rphplc)
-
A novel methodology for the enantiomeric resolution of methamphetamine, its precursors and intermediates by GC-MS
PublicationImpurity profiling and classification of abused drugs using chiral analytical techniques is of particular interest and importance because of the additional information obtained from this approach. When these methods are applied to the synthesis of illicitly used substances, they can supply valuable information about the conditions/chemicals used in the synthesis. In this study, simultaneous chiral separation of methylamphetamine,...
-
Evaluation of the photoprotective effect of β-cyclodextrin on the emission of volatile degradation products of ranitidine
PublicationThe process of the photo-excitation of ranitidine hydrochloride (RAN) in a solid state makes visible changes to its colour and generates an unpleasant odour. The purpose of the present study was to observe the protective effects of ˇ-cyclodextrin (CD) complexation as well as the effect of the mixture of two stoichiometries 1:1 and 1:2 (RAN:CD, IC) on the photostability of samples in a solid state. Samples of inclusion complexes...
-
Evaluation of the photoprotective effect of ˇ-cyclodextrin on the emission of volatile degradation products of ranitidine
PublicationThe process of the photo-excitation of ranitidine hydrochloride (RAN) in a solid state makes visible changes to its colour and generates an unpleasant odour. The purpose of the present study was to observe the protective effects of ˇ-cyclodextrin (CD) complexation as well as the effect of the mixture of two stoichiometries 1:1 and 1:2 (RAN:CD, IC) on the photostability of samples in a solid state. Sam- ples of inclusion complexes...
-
Decentralized control of a different rated parallel UPS systems
PublicationThe paper presents the single phase uninterruptible power supply (UPS) system with galvanic separated DC-AC-DC-AC converters operating in parallel. The CAN physical layer based system of communication between converters has been developed and applied, which allow to utilize a decentralized master-slave control providing high availability factor of the whole UPS system. The control system of particular converters has been developed...
-
Revalorisation of the Szewalski’s concept of the law of varying the last-stage blade retraction in a gas-steam turbine
PublicationThe article presents the implementations of the free vortex law to the blade of the last stage of a gas-steam turbine. First, a thermodynamic analysis was carried out, determining the parameters at the inlet, then the number of stages of the high and low-pressure part of the turbine was constructed, together with the kinematics and velocity vectors for subsequent stages of the axial turbine. The last step of article was to take...
-
Elucidation of transformation pathway of ketoprofen, ibuprofen, and furosemide in surface water and their occurrence in the aqueous environment using UHPLC-QTOF-MS
PublicationThe identification and determination of transformation products (TPs) of pharmaceuticals is essential nowadays, in order to track their fate in the aqueous environment and, thus, to estimate the actual pollution. However, this is a challenging task due to the necessity to apply high-resolution instruments enable to detect known and unknown compounds. This work presents the use of liquid chromatography quadrupole time-of-flight...
-
Modulation of CYP3A4 activity and induction of apoptosis, necrosis and senescence by the antitumor imidazoacridinone C-1311 in human hepatoma cells
PublicationThere is increasing evidence that the expression level of drug metabolic enzymes affects the final cellular response following drug treatment. Moreover, anti-tumour agents may modulate enzymatic activity and/or cellular expression of metabolic enzymes in tumour cells. We investigated the influence of CYP3A4 overexpression on the cellular response induced by the anti-tumour agent C-1311 in hepatoma cells. C-1311-mediated CYP3A4...
-
Development and evaluation of RADA-PDGF2 self-assembling peptide hydrogel for enhanced skin wound healing
PublicationBackground: Wound healing complications affect numerous patients each year, creating significant economic and medical challenges. Currently, available methods are not fully effective in the treatment of chronic or complicated wounds; thus, new methods are constantly sought. Our previous studies showed that a peptide designated as PDGF2 derived from PDGF-BB could be a promising drug candidate for wound treatment and that RADA16-I...
-
Anti-cancer effect of Rumex obtusifolius in combination with arginase/nitric oxide synthase inhibitors via downregulation of oxidative stress, inflammation, and polyamine synthesis
PublicationCancer continues to be a leading cause of death worldwide, making the development of new treatment methods crucial in the fight against it. With cancer incidence rates increasing worldwide, ongoing research must focus on identifying new and effective ways to prevent and treat the disease. The combination of herbal extracts with chemotherapeutic agents has gained much interest as a novel strategy to combat cancer. Rumex obtusifolius...
-
Identification of novel halogenated naturally occurring compounds in marine biota by high-resolution mass spectrometry and combined screening approaches
PublicationMarine animals, plants or bacteria are a source of bioactive naturally-occurring halogenated compounds (NHCs) such as bromophenols (BPs), bromoanisoles (BAs) and hydroxylated or methoxylated analogues of polybrominated diphenyl ethers (HO-PBDEs, MeO-PBDEs) and bromobiphenyls (HO-BBs, MeO-BBs). This study applied a comprehensive screening approach using liquid chromatography high-resolution mass spectrometry and combining target,...
-
Drug-Eluting Biopsy Needle as a Novel Strategy for Antimicrobial Prophylaxis in Transrectal Prostate Biopsy
PublicationOBJECTIVES: To preclinically evaluate drug-eluting biopsy needles (patent pending WO2016118026) as a new potential way of antimicrobial prophylaxis for transrectal prostate biopsy. METHODS: Twenty steel biopsy needles have been coated with polyvinyl alcohol, ciprofloxacin, and amikacin. Modified biopsy needles have been randomly divided into 3 groups (1:2:1 ratio). Needles from group I were immersed for 30 minutes in dedicated...
-
Exploration of optical fibres as a carrier for new benzene and toluene matrix-free reference materials
PublicationTo meet high expectations concerning precision and accuracy of reference materials, preparation of matrixfree reference materials using thermal decomposition-gas chromatography-mass spectrometry (TD-GC-MS) was proposed in this study. In the paper, the results obtained in preparation of the new reference materials for benzene and toluene are presented, based on the thermal decomposition technique of compounds chemically bound to...
-
Fatigue Bending of V-Notched Cold-Sprayed FeCoCrNiMn Coatings
PublicationCold-spray coatings were produced by FeCoCrNiMn high-entropy alloy powders deposited on carbon steel substrate. The coatings were realized at intermediate temperature and high pressure (at 1100 °C and 7 MPa). The coating microstructure was characterized by scanning electron microscopy and X-ray diffraction, revealing a very dense deposition and high flattening ratio of the splatted particles. This had a large influence on the...
-
An asymmetrical λ-foot of condensing steam flow in the IMP PAN nozzle
PublicationIn the present paper we have focused on the precise prediction of the spontaneous condensation phenomena in wet steam flow. Novelty of our approach lies on modelling both the moment of initiation of a phase transition, as well as the moment of its reverse progress - called here re-vaporization of the condensate phase. The practical issue is to elaborate of a model of spontaneous condensation/vaporization of water steam flow...
-
The effect of reduced pressure on carbon dioxide flow boiling heat transfer in minichannels
Publication. In the paper presented are the results of the study on the effect of reduced pressure on flow boiling heat transfer data in minichannels as well as conventional ones. That effect renders that most of heat transfer correlations fail to return appropriate results of predictions. Mostly they have been developed for the reduced pressures from the range 0.1-0.3. The special correction has been postulated to the in-house model of flow...
-
Impact of digital signal processing on FOC current feedback in high-speed PMSM drive
PublicationIn applications where size and weight of the electric motor are among major design concerns, Permanent Magnet Synchronous Motors (PMSMs) with wide operational speed-range are commonly preferred. Due to limited inverter switching frequency, high-speed operation of a drive results in a low ratio between the switching frequency and the fundamental frequency of motor voltage. Such operating conditions have been recently identified...
-
Zagadnienia tribologiczne w hamulcu silnika hydraulicznego
PublicationPrzedmiotem badań był prototypowy hamulec cierny wielopłytkowy do silnika satelitowego SM-0,6 o teoretycznej objętości roboczej 16,7 cm3/obr. Hamulec ten zbudowany był z 27 tarcz ciernych wykonanych z materiału TOLOX oraz z pakietu sprężyn talerzowych zamontowanych w układzie X. Zablokowanie hamulca następuje w skutek siły docisku pakietu sprężyn talerzowych płytek ciernych co następuje w chwili spadku ciśnienia w komorze tłoka...
-
Ionic liquids-based microextraction techniques
PublicationIn recent years, the development of highly efficient analytical techniques is of great importance, however, the direct analysis of complex sample matrix is still impossible in many cases. Therefore, the step of sample preparation is commonly involved in an analytical procedure. Over the years, it has been realized that the major source of inaccuracy and imprecision on general analysis results from the operations associated to sample...
-
Modelling of saturated, subcooled and post-dryout flow boiling with the energy dissipation based semi-empirical model
PublicationA comprehensive semi-empirical model for saturated, subcooled and post dryout heat transfer is presented based on considerations of energy dissipation in the flow. The fundamental hypothesis in the model is the fact that heat transfer during flow boiling can be treated as a sum of two contributions constituting the total energy dissipation in the flow, namely the energy dissipation due to the shearing flow without the bubbles and...
-
EVALUATION OF LIQUID-GAS FLOW IN PIPELINE USING GAMMA-RAY ABSORPTION TECHNIQUE AND ADVANCED SIGNAL PROCESSING
PublicationLiquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of thegamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble,...
-
Novel fast analytical method for indirect determination of MCPD fatty acid esters in edible oils and fats based on simultaneous extraction and derivatization
PublicationA novel method for indirect determination of MCPD esters levels in lipid samples has been developed. The method is based on combination of extraction and derivatisation in the same sample preparation step. It is achieved by the application of diethyl ether as extraction solvent for isolation of released from esterified forms analytes from water phase and dilution solvent for solid PBA – derivatisation agent. It is a noteworthy...
-
Synthesis and properties of porous Sr 0.96 Y 0.04 Ti 1−x Nb x O 3
PublicationA series of porous, single phase Sr0.96Y0.04Ti1-xNbxO3 samples was obtained using a wet synthesis method (modified citrate sol-gel) method. Temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPO) measurements have shown high stability of the obtained material in variable (oxidizing/reducing) atmospheres. All samples exhibit high conductivity in hydrogen atmosphere with the highest value (around 1S/cm)...
-
Insight into Potassium Vanadates as Visible-Light-Driven Photocatalysts: Synthesis of V(IV)-Rich Nano/Microstructures for the Photodegradation of Methylene Blue
PublicationPhotocatalysis is regarded as a promising tool for wastewater remediation. In recent years, many studies have focused on investigating novel photocatalysts driven by visible light. In this study, K2V6O16·nH2O nanobelts and KV3O8 microplatelets were synthesized and investigated as photocatalysts. Samples were obtained via the facile method based on liquid-phase exfoliation with ion exchange. By changing the synthesis temperature...
-
New Procedures for Control of Industrial Effluents Treatment Processes
PublicationThis work presents the procedures for monitoring volatile organic compounds during treatment of industrial effluents. The investigation was carried out for a specific effluent—caustic effluent from bitumen production. The developed procedures enable more detailed control of the effectiveness of wastewater treatment than standard procedures. Caustic effluents from bitumen production have a complex physicochemical form and consist...
-
Mechanism-based inactivation of human cytochrome P450 1A2 and 3A4 isoenzymes by antitumor triazoloacridinone C-1305.
Publication5-Dimethylaminopropylamino-8-hydroxytriazoloacridinone, C-1305, is a promising antitumor therapeutic agent with high activity against several experimental tumors. It was determined to be a potent and selective inhibitor of liver microsomal and human recombinant cytochrome P450 (CYP) 1A2 and 3A4 isoenzymes. Therefore, C-1305 might modulate the effectiveness of other drugs used in multidrug therapy. The objective of this study was...
-
Numerical study of turbulent flow and heat transfer of nanofluids in pipes
PublicationIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (6 000 < Re < 12 000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data of Vajjha et al. [1]. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
-
The effect of polyamide PA12 and polyester PBT blocks' lengths on the structure and propertries of multiblock terpoly(amide-block-ester-block-amide) (TPAEA)
PublicationThe ternary multiblock system terpoly(amide-b-ester-b-amide) (TPAEA) of the chemical structure: poly[(oligoamide-6.36)-block-(tetramethylene terephthalate)-block-laurolactam)] -(PA6.36-b-PBT-b-PA12)n- has been obtained (Table 1). In this system the third component (PBT block here), characterized with the proper molecular weight, is dissolved in hard phase of PA12 blocks and partially dissolved in soft phase of PA6.36. The effects...
-
Exploring hydrogen energy systems: A comprehensive review of technologies, applications, prevailing trends, and associated challenges
PublicationExploring hydrogen energy and its associated technologies is a pivotal pathway towards achieving carbon neutrality. This article comprehensively reviews hydrogen production technologies, storage technologies, and end-use applications of hydrogen, based on the input energy source, operating conditions, conversion efficiency, energy density, and unit investment cost. The review also highlights the advantages, disadvantages, and technological readiness...
-
Copper(I) iodide ribbons coordinated with thiourea derivatives
PublicationTwo products of the reactions of CuI with 1-benzoyl-3-(4-bromophenyl)thiourea and with 1-benzoyl-3-(2-iodophenyl)thiourea have been obtained and characterized, namely poly[[[1-benzoyl-3-(4-bromophenyl)thiourea-κS]-µ3-iodidocopper(I)] acetone hemisolvate], {[CuI(C₁₄H₁₁BrN₂OS)]‧0.5C₃H₆O}ₙ, and poly-[µ₄-iodido-µ₃-iodido-[N-(benzo[d]thiazol-2-yl)benzamide-κN]dicopper(I)], [Cu₂I₂(C₁₄H₁₀N₂OS)]ₙ. Their structures, determined by single-crystal...
-
Identification and characterization of single-stranded DNA-binding protein from the facultative psychrophilic bacteria Pseudoalteromonas haloplanktis
PublicationSingle-stranded DNA-binding protein (SSB) plays an important role in DNA metabolism such as DNAreplication, repair, and recombination, and is essential for cell survival. This study reports on the ssb-likegene cloning, gene expression and characterization of a single-stranded DNA-binding protein of Pseudoal-teromonas haloplanktis (PhaSSB) and is the first report of such a protein from psychrophilic microorganism.PhaSSB possesses...
-
A novel analytical approach in the assessment of unprocessed Kaffir lime peel and pulp as potential raw materials for cosmetic applications
PublicationVolatile fraction of fruits is a rich source of bioactive and aroma compounds, which can be used in the cosmetics industry after meeting relevant criteria. This is particularly evident in citrus fruits, especially in Citrus hystrix, in which the headspace consists mainly of terpenes. Due to the insufficient sensitivity of analytical methods, essential oils are used in investigations in contrast to fresh fruits. Therefore, a novel...
-
Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach
PublicationThis work presents an approach that integrates the results of measuring, analyzing, and modeling air flow phenomena driven by pressurized air in a flue organ pipe. The investigation concerns a Bourdon organ pipe. Measurements are performed in an anechoic chamber using the Cartesian robot equipped with a 3D acoustic vector sensor (AVS) that acquires both acoustic pressure and air particle velocity. Also, a high-speed camera is employed...
-
Pressure-induced flow processing behind the superior mechanical properties and heat-resistance performance of poly(butylene succinate)
PublicationWe propose a pressure-induced flow (PIF) processing method for the simultaneous enhancement of strength, toughness, and heat resistance of biodegradable poly(butylene succinate) (PBS). The pressure and temperature were systematically adjusted to optimize the tensile strength of PBS. Under the optimized processing conditions, the structured PBS was characterized by relatively high strength of 89.5 MPa, toughness of 21.4 kJ·m−2 ,...
-
Role of the Solvation Water in Remote Interactions of Hyperactive Antifreeze Proteins with the Surface of Ice
PublicationMost protein molecules do not adsorb onto ice, one of the exceptions being so-called antifreeze proteins. In this paper, we describe that there is a force pushing an antifreeze protein molecule away from the ice surface when it is not oriented with its ice-binding plane toward the ice and that this pushing force may be also present even when the protein is oriented with its ice-binding plane toward the ice. This force is absent...
-
How thermal stability of ionic liquids leads to more efficient TiO2-based nanophotocatalysts: Theoretical and experimental studies
PublicationIonic liquids (ILs) containing distinct nitrogen-bearing organic cations (pyridinium, pyrrolidinium, imidazolium, ammonium, morpholinium) were first used for the preparation of 23 IL-TiO2 types of composites by ionic liquid assisted solvothermal synthesis. These 23 optimal ILs structures (i.e. compounds exhibiting an optimal combination of specific properties, functionality, and safety) for synthesis and experimental validation...
-
Superconductivity in the niobium-rich compound Nb5Se4
PublicationThe niobium rich selenide compound Nb5Se4 was synthesized at ambient pressure by high-temperature solid–state reaction in a sealed Ta tube. Resistivity and heat capacity measurements reveal that this compound is superconducting, with a Tc = 1.85K. The electronic contribution to the specific heat γ and the Debye temperature are found to be 18.1 mJmol−1K−2 and 298 K respectively. The calculated electron-phonon coupling constant λep...
-
The impact of addition of olive oil on thermal degradation of refined rapeseed oil
PublicationFats are an important component of the everyday diet and have a significant impact on the proper functioning of human organism. However, during the process of frying chemical transformations take place in the oil; hence fats characterised by high oxidative stability should be given preference. The aim of this work was to determine the quality of rapeseed oil, blended oil, and refined olive oil, all sourced from the domestic market....
-
Application of analytical procedure based on accelerated solvent extraction and ion chromatography technique for determination of thiocyanate and other inorganic ions in human placenta samples
PublicationExposure of a pregnant woman during pregnancy is a special case of exposure to toxic substances. Samples of placenta collected for the studies had been prepared with the technique of accelerated solvent extraction and later analyzed for the presence of thiocyanate ion and other inorganic ions, with the use of the technique of ion chromatography. The concentration of thiocyanate ion in placenta samples collected from active smokers...
-
Pyrolysis and Torrefaction—Thermal Treatment of Creosote-Impregnated Railroad Ties as a Method of Utilization
PublicationA fundamental issue of waste management and the rail transport industry is the problem of utilizing used railroad ties. Wooden railroad ties are treated with a preservative, usually creosote. Due to their high toxicity, railroad ties are considered hazardous waste and must be utilized under various directives. It is proposed to utilize the troublesome waste by using the pyrolysis and torrefaction process. The research proves that...
-
Zastosowanie addytywów w separacji pianowej białek serwatkowych i białek mlecznych
PublicationZaproponowano proces separacji pianowej do wydzielania białek ze strumieni poprodukcyjnych przemysłu mleczarskiego Ponadto zaproponowano zastosowanie w separacji pianowej białek serwatkowych i mlecznych addytywów dopuszczonych ustawą do stosowania w żywności. Jako cel pracy przyjęto uzyskanie wyników uzasadniających wybór takich addytywów, które intensyfikują przebieg i polepszają wynik procesu separacji pianowej białek. W części...
-
Comprehensive two-dimensional gas chromatography for determination of the terpenes profile of blue honeysuckle berries
PublicationTerpenes are the main group of secondary metabolites, which play essential role in human. The establishment of the terpenes profile of berries of different blue honeysuckle cultivars was achieved by headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (HS-SPME/GCGC-TOFMS). The berries were found to contain 44 terpenes identified by GCGC-TOFMS....
-
Temperature Measurements at Tyre Tread Rubber on Sandpaper Oscillatory Sliding Contacts Using Acicular Grindable Thermocouples
PublicationThe tribological performance of tyre–road contacts depends crucially on the contact temperature. This study investigates the reliability and accuracy of acicular grindable thermocouples possessing an original needle-shaped wearable part as applied to measuring temperature at the oscillatory sliding contact between a rubber tyre tread sample and a sandpaper. A linear oscillatory tribometer is used to imitate the sliding phase of...
-
A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
PublicationMulti-phase motors have recently replaced three-phase induction motors in a variety of applications due to the numerous benefits they provide, and the absence of speed sensors promotes induction motors with variable speed drives. Sensorless speed control minimizes unnecessary speed encoder cost, reduces maintenance, and improves the motor drive’s reliability. The performance comparison of the fuzzy sliding mode controller (FSMC)...
-
A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
PublicationMulti-phase motors have recently replaced three-phase induction motors in a variety of applications due to the numerous benefits they provide, and the absence of speed sensors promotes induction motors with variable speed drives. Sensorless speed control minimizes unnecessary speed encoder cost, reduces maintenance, and improves the motor drive’s reliability. The performance comparison of the fuzzy sliding mode controller (FSMC)...
-
Biomechanical causes for failure of the Physiomesh/Securestrap system
PublicationThis study investigates the mechanical behavior of the Physiomesh/Securestrap system, a hernia repair system used for IPOM procedures associated with high failure rates. The study involved conducting mechanical experiments and numerical simulations to investigate the mechanical behavior of the Physiomesh/Securestrap system under pressure load. Uniaxial tension tests were conducted to determine the elasticity modulus of the Physiomesh...
-
The importance of individual spray properties in performance improvement of a urea-SCR system employing flash-boiling injection
PublicationThe appropriate mixing of a urea–water solution (UWS) with exhaust gases in a selective catalytic reduction system is crucial to efficiently reduce nitrogen oxides and diminish the deposition of liquid wall film. One of the methods to enhance the mixing of the UWS with the exhaust gases is a flash-boiling injection. Its positive effect has been linked with a reduced Sauter mean diameter (SMD) and improved evaporation, but the...
-
The domination of ionic conductivity in tetragonal phase of the organometal halide perovskite CH3NH3PbI3-xClx
PublicationOrganometal trihalide perovskites have recently gained extreme attention due to their high solar energy conversion in photovoltaic cells. Here, we investigate the contribution of iodide ions to a total conductivity of the mixed lead halide perovskite CH3NH3PbI3−xClx with a use of the modified DC Hebb–Wagner polarization method. It has been identified that an ionic conductivity dominates in tetragonal phase which is associated with room...
-
Modelling and analysis of medium frequency transformers for power converters
PublicationThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
-
A new construction of shell-and-tube heat exchanger with impinging jets and minichannels technologies for heat recovery from gases – experimental analysis
PublicationA dynamic development of technologies allowing waste heat utilization is observed in a correspondence with a pro-ecological approach of the zero waste idea. Such approach becomes the most demanding in the area of low-temperature was heat sources, especially gaseous media. Till now, they were usually not utilized due to unfavorable thermal conditions and high costs. Therefore, the zero waste approach directs research on techniques...
-
Influence of Antimony Substitution on Spontaneous Strain and Thermodynamic Stability of Lanthanum Orthoniobate
PublicationThe analysis of the antimony substitution influence on temperature dependence of unit cell distortion has been done. The values of spontaneous strain and Landau order parameter for three different antimony contents varied had been calculated. The phase transition occurring for antimony substituted lanthanum orthoniobate was found to be second order. The high temperature solution calorimetry method has been used to investigate...