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1.
Sensors (Basel) ; 22(24)2022 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-36560188

RESUMEN

In modern systems with induction motors (IM), in addition to precision, it is also very important to ensure the highest possible reliability and safety. To ensure the above, information about the stator current value is required. If the current sensor (CS) fails, a redundant sensor or an algorithmic solution can be used. The Luenberger observer (LO) can be used to estimate the lost stator current without increasing the cost of the drive system. However, this solution is based on the mathematical model of IM, which is sensitive to its parameters. Therefore, this paper presents a modified LO (MLO) and investigates the effect of a coefficient in the error gain matrix on improving robustness to changes in the IM parameters. As shown by extensive studies, the proposed solution has significantly reduced the influence of the IM parameters on the accuracy of the stator current estimation, which has not been previously reported in the known literature.


Asunto(s)
Escarabajos , Animales , Reproducibilidad de los Resultados , Incertidumbre
2.
Molecules ; 27(19)2022 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-36235143

RESUMEN

The aim of this paper is to present a comprehensive overview of the main aims and scopes in screening of botanicals, a task of which thin-layer chromatography (TLC) is, on an everyday basis, confronted with and engaged in. Stunning omnipresence of this modest analytical technique (both in its standard format (TLC) and the high-performance one (HPTLC), either hyphenated or not) for many analysts might at a first glance appear chaotic and random, with an auxiliary rather than leading role in research, and not capable of issuing meaningful final statements. Based on these reflections, our purpose is not to present a general review paper on TLC in screening of botanicals, but a blueprint rather (illustrated with a selection of practical examples), which highlights a sovereign and important role of TLC in accomplishing the following analytical tasks: (i) solving puzzles related to chemotaxonomy of plants, (ii) screening a wide spectrum of biological properties of plants, (iii) providing quality control of herbal medicines and alimentary and cosmetic products of biological origin, and (iv) tracing psychoactive plants under forensic surveillance.


Asunto(s)
Plantas Medicinales , Cromatografía en Capa Delgada/métodos , Plantas Medicinales/química , Control de Calidad
3.
Pathogens ; 11(8)2022 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-36014965

RESUMEN

Native communities of arbuscular mycorrhizal fungi (AMF) constitute a natural biofertilization, biocontrol, and bioprotection factor for most agricultural crops, including cereals. The present study investigated the native AMF population in cultivated spelt, i.e., a cereal that has not been analyzed in this respect to date. In particular, the aim of the study was to determine the number of spores and the degree of AMF root colonization in two spelt cultivars (Franckenkorn and Badengold) from a 3-year monoculture grown in two different cultivation systems: conventional tillage and no-tillage systems. The study showed considerable accumulation of AMF spores in the soil (on average 1325 in 100 g of air-dry soil), with a wide range of their numbers, and not a very high degree of endomycorrhizal colonization (on average from 3.0% to 31%). The intensity of AMF growth in the subsequent cultivation years gradually increased and depended on the cultivation system as well as the growth stage and cultivar of the spelt. It was found that both analyzed AMF growth indices in the no-tillage system were positively correlated with each other. Moreover, their values were higher in the no-tillage system than in the conventional system, with statistical significance only for the number of spores. This was mainly observed in the variant with the Franckenkorn cultivar. The effect of the growing season was evident in both cultivation systems and spelt cultivars. It was reflected by intensification of sporulation and mycorrhization of spelt roots by AMF in summer (maturation stage) compared with the spring period (flowering stage).

4.
Pathogens ; 11(3)2022 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-35335665

RESUMEN

The present study is the first report of a detailed analysis of the frequency of Fusarium and genera related to Fusarium colonizing the root zone of clovers and grasses growing in a permanent meadow established on peat-muck soil in a post-bog habitat. The isolation of fungi was carried out on the Nash and Snyder medium with the plate dilution method. The taxonomic identification of the collection of pure fungal cultures was based on morphological features revealed by macroscopic and microscopic observations. The species dominance coefficients, Marczewski-Steinhaus and Simpson species diversity index were calculated. Eight Fusarium complexes were distinguished. The distribution of the Fusarium population was uneven, which was generally reflected in a higher frequency of the F. oxysporum species complex in the clover root zone and M. nivale, F. avenaceum from the Fusarium tricinctum species complex, and F. culmorum from the F. sambucinum species complex in the grass root zone. The highest similarity of fungi was determined in the rhizoplane and the endorhizosphere. The highest species diversity and the highest population size were determined in the rhizosphere soil. The fertilization treatment reduced the growth rates in the Fusarium sensu lato and in genera related to Fusarium, as evidenced by the decrease in the total abundance and species richness. The root colonization by the Fusarium, especially the F. oxysporum species complex, was not accompanied by plant pathologies, which suggests a saprotrophic and endophytic rather than parasitic character of the relationships with the plant host.

5.
Sci Rep ; 12(1): 2142, 2022 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-35136194

RESUMEN

The process of dispersal of the potentially disease-causing, geophilic and keratinolytic fungal strain Aphanoascus keratinophilus (the perfect, sexual stage of Chrysosporium keratinophilum) by the rook Corvus frugilegus was studied. The source of A. keratinophilus strains was pellets of the rook, thus far not considered a carrier of this particular opportunistic pathogen. Pellets collected from breeding colonies of rooks were analysed in terms of the occurrence of keratinolytic fungi with the application of the native keratin bait method. Among the 83 rook pellets analysed, 24 (29%) were infected by keratinophilic fungi. Pure cultures of the fungi were identified to species based on traditional morphological features. Traditional mycological identification was verified by the PCR-RFLP molecular identification method as well as DNA sequencing. The obtained results showed the presence of 90 Aphanoascus keratinophilus strains, 6 Chrysosporium tropicum strains, and 3 Chrysosporium pannicola strains. The PCR melting profile (PCR-MP) method was used to identify intraspecies variations of the 90 analysed A. keratinophilus strains. The dispersal of genotypes and possible pathways of A. keratinophilus dispersal and infection via rook pellets were analysed.


Asunto(s)
Cuervos/microbiología , Micosis/transmisión , Onygenales/genética , Animales , Polonia
6.
J Chromatogr Sci ; 60(4): 372-386, 2022 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-34089050

RESUMEN

We investigated the dual retention mechanism in thin-layer chromatography taking place on three stationary phases of different polarity (C-18, plain silica gel and DIOL) and using binary mobile phases composed of acetonitrile as the main component and water, or methanol as a modifier. As the test analytes, we selected a set of 12 compounds of pharmaceutical importance and considerably different chemical structure, i.e. the imidazoline and serotonin receptor ligands, and their related compounds. Retention of each analyte in each investigated chromatographic system was determined in a wide enough range of the mobile phase composition, with volume fraction of the mobile phase modifier ranging from 0.10 to 0.90. Calculation of the exact turning point values as a proof of occurrence of the reversed-phase hydrophilic interaction chromatography (HILIC/RP) retention mechanism was based on the multimodal retention model. The dual retention mode was described with the use of the volume fraction of the mobile phase modifier, the total polarity and the total solubility models. For the DIOL, C-18 and silica gel stationary phase, the dual (HILIC/RP) retention mechanism was confirmed. In the case of the DIOL stationary phase and acetonitrile/methanol mobile phase, the observed retention mechanism was more complicated than the dual HILIC/RP one.


Asunto(s)
Cromatografía de Fase Inversa , Metanol , Acetonitrilos , Cromatografía de Fase Inversa/métodos , Cromatografía en Capa Delgada , Interacciones Hidrofóbicas e Hidrofílicas , Gel de Sílice
7.
Molecules ; 26(2)2021 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-33477273

RESUMEN

The aim of this study was to evaluate the bioremoval mechanism of anthracycline antibiotics by the white-rot fungus B. adusta CCBAS 930. The activity of oxidoreductases and levels of phenolic compounds and free radicals were determined during the biotransformation of anthraquinone antibiotics: daunomycin (DNR) and doxorubicin (DOX) by B. adusta strain CCBAS 930. Moreover, phytotoxicity (Lepidium sativum L.), ecotoxicity (Vibrio fischeri), genotoxicity and cytotoxicity of anthraquinone dyes were evaluated before and after biological treatment. More than 80% and 90% of DNR and DOX were removed by biodegradation (decolorization). Initial solutions of DNR and DOX were characterized by eco-, phyto-, geno- and cytotoxicity. Despite efficient decolorization, secondary metabolites, toxic to bacteria, formed during biotransformation of anthracycline antibiotics in B. adusta CCBAS 930 cultures. DNR and DOX metabolites did not increase reactive oxygen species (ROS) production in human fibroblasts and resazurin reduction. DNR metabolites did not change caspase-3 activity.


Asunto(s)
Antraciclinas , Coriolaceae/enzimología , Citotoxinas , Daño del ADN/efectos de los fármacos , Fibroblastos/metabolismo , Proteínas Fúngicas/química , Estrés Oxidativo/efectos de los fármacos , Peroxidasas/química , Antraciclinas/química , Antraciclinas/farmacología , Línea Celular , Citotoxinas/química , Citotoxinas/farmacología , Humanos
8.
World J Microbiol Biotechnol ; 37(1): 1, 2020 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-33349893

RESUMEN

We used a ligninolytic strain of the white-rot fungus B. adusta CCBAS 930 and its mutants with modified ligninolytic activity to assess their potential to remove of molasses. The analyzed strains have been shown to be able to decolorize 1% or 2% molasses solutions containing brown-colored toxic melanoidins. It was found that the decolorization process was determined by the transition to the stage of production of sporulating aerial mycelium (liquid and agar cultures) coupled with an increase in peroxidase activity, which was accompanied by a decrease in the level of melanoidin, free radicals, and phenolic compounds. Four different peroxidase activities were detected in post-culture liquids, i.e. horseradish-like (HRP-like), manganese-dependent (MnP), lignin (LiP), and versatile (VP) peroxidase activities. The HRP-like peroxidase was characterized by the highest activity. The efficiency of removal of melanoidins from a 1% molasses solution by the parental strain and the mutants was dependent on the culture method. The highest efficiency was noted in immobilized cultures (threefold higher than in the mycelium-free cultures), which was accompanied by stimulation of HRP-like peroxidase activity. Mutant 930-5 was found to be the most effective in the decolorization and decomposition of melanoidin. The HRP-like activity in the immobilized cultures of B. adusta 930-5 was 640-fold higher than in the mycelium-free cultures of the fungus. Moreover, decolorization and biodegradation of melanoidin by B. adusta CCBAS 930 and 930-5 was coupled with detoxification.


Asunto(s)
Beta vulgaris/química , Coriolaceae/crecimiento & desarrollo , Peroxidasa/metabolismo , Polímeros/química , Biodegradación Ambiental , Coriolaceae/genética , Coriolaceae/aislamiento & purificación , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Técnicas Microbiológicas , Melaza , Mutación , Peroxidasa/genética , Microbiología del Suelo
9.
J Appl Clin Med Phys ; 21(11): 237-246, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33111500

RESUMEN

INTRODUCTION: The purpose of this study was to present the optimization process of CT parameters to reduce patient exposure during bone SPECT/CT without affecting the quality of SPECT images with attenuation correction (AC). MATERIAL AND METHODS: A fillable phantom reflecting realistic bone scintigraphy conditions was developed and acquired on an AnyScan SC. SPECT/CT scans were carried out with different x-ray tube current values (10, 20, 30, 40, 50, 60, 70, 90, 110, 130, 150, and 200 mA) at three different high-voltage values (80, 100, and 120 kV). The contrast (C) and coefficients of variation (CV) in the SPECT images as well as the signal-to-noise ratio (SNR) and noise (SDCT ) in the CT images with CTDIvol were measured. An optimal acquisition protocol that obtained SPECT/CT images with no artifacts on both CT and SPECT images, acceptable C, SNR, CV, and SDCT values, and the largest reduction in patient exposure compared to the reference acquisition procedure was sought. RESULTS: The optimal set of parameters for bone SPECT/CT was determined based on a phantom study. It has been implemented in clinical practice. Two groups of patients were examined according to the baseline and optimized protocols, respectively. The new SPECT/CT protocol substantially reduced patients' radiation exposure compared to the old protocol while maintaining the required diagnostic quality of SPECT and CT images. CONCLUSIONS: In the study, we present a methodology that finds a compromise between diagnostic information and patient exposure during bone SPECT/CT procedures.


Asunto(s)
Tomografía Computarizada de Emisión de Fotón Único , Tomografía Computarizada por Rayos X , Humanos , Fantasmas de Imagen , Dosis de Radiación , Relación Señal-Ruido
10.
Front Chem ; 8: 541, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32695746

RESUMEN

We present an overview of our studies on the hampering effect of heavy water (D2O) on spontaneous oscillatory peptidization of selected proteinogenic α-amino acids. The investigated set of compounds included three endogenous and two exogenous species. The experiments were carried out with use of high-performance liquid chromatography (HPLC), mass spectrometry (MS) and scanning electron microscopy (SEM). These techniques were chosen to demonstrate spontaneous oscillatory peptidization of α-amino acids in an absence of D2O (HPLC) and the hampering effect of D2O on peptidization (HPLC, MS and SEM). The HPLC analyses were carried out at 21 ± 0.5°C with each α-amino acid freshly dissolved in the binary liquid mixture of organic solvent + H2O, 70:30 (v/v) or in pure D2O for several dozen hours or several hours, respectively. The analyses with use of MS and SEM were carried out, respectively, after 7 days and 1 month of sample storage period in the darkness at 21 ± 0.5°C and for these experiments, each α-amino acid was dissolved in the liquid mixture of organic solvent + X, 70:30 (v/v), where X: H2O + D2O in volume proportions from 30:0 to 0:30. The results obtained with use of HPLC, MS and SEM point out to the strong hampering effect of D2O on the oscillations and peptidization yields, yet the dynamics of these processes significantly depends on chemical structure of a given α-amino acid.

11.
J Chromatogr A ; 1625: 461230, 2020 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-32709311

RESUMEN

Two isomeric biphenyl neolignans, magnolol and honokiol, are considered as constituents responsible for the healing effect of magnolia bark, a traditional Oriental medicine. To survey the increasing number of dietary supplements that contain magnolia bark or its extract, an affordable quantitative thin-layer chromatography (TLC) - densitometry method was developed. The methanol extracts were analyzed on the silica gel plates after manual sample application using n-hexane - ethyl acetate - ethanol (16:3:1, v/v/v) as a mobile phase. For quantitation, the chromatograms were scanned in the absorbance mode at the wavelength λ = 290 nm. The limits of detection and quantitation were 90 and 280 ng/zone for magnolol and 70 and 200 ng/zone for honokiol, respectively. None of the two targeted neolignans were detected in two of the six analyzed supplements. In the other four samples, the measured amounts were between 0.95-114.69 mg g-1 for magnolol and 4.88-84.86 mg g-1 for honokiol. Moreover, separations of these two neolignans on the TLC and high-performance TLC (HPTLC) layers were compared and HPTLC was combined with antioxidant (DPPH) and antibacterial (Bacillus subtilis and Aliivibrio fischeri) assays and mass spectrometry (MS), using the elution-based interface. Both magnolol and honokiol exhibited effects in all bioactivity assays. The HPTLC-MS tests confirmed purity of neolignan zones in the extracts of dietary supplements and supported tentative identification of the alkaloid piperine and the isoflavone daidzein as additional bioactive components of the investigated dietary supplements. Using the same mobile phase in the orthogonal directions 2D-HPTLC-MS experiments proved degradation, i.e., instability of magnolol and honokiol on the silica gel adsorbent.


Asunto(s)
Compuestos de Bifenilo/análisis , Cromatografía en Capa Delgada/métodos , Suplementos Dietéticos/análisis , Lignanos/análisis , Densitometría , Límite de Detección , Magnolia/química , Magnolia/metabolismo , Medicina Tradicional de Asia Oriental , Corteza de la Planta/química , Corteza de la Planta/metabolismo
12.
J Environ Manage ; 266: 110573, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32314744

RESUMEN

One of the links in the environmental management chain is the environmentally friendly utilization of the emerging post-industrial waste and improvement of the methods of processing thereof. The aim and novelty of this research was to evaluate the potential of fungi to purify wastewater containing post-industrial lignin, i.e. waste originating from the pulp and paper industry. Trichoderma were dominant in the composts with different qualities and quantities of lignocellulosic compounds. The Trichoderma strains used in the research were isolated from two lignocellulosic composts at three different time points (from 10-, 20- and 30-week-old composting mass). Eighteen strains of the genus Trichoderma were tested for their ability to biodegrade 0.2% post-industrial lignin. It was evaluated by determination of decolorization, activities of ligninolytic enzymes, and concentration of phenolic compounds in the post-culture liquid. The Trichoderma strains isolated from 10-week-old compost I and 30-week-old compost II showed the highest decolorization activity and biotransformation of dark post-industrial lignin. All strains secreted horseradish-like peroxidase (HRP-like), superoxide dismutase-like (SOD-like), xylanase, and phenolic compounds. Strains isolated from 30-week-old compost I and from 10-week-old compost II released the greatest amounts of phenolic compounds into the culture liquid containing post-industrial lignin. The strains isolated from 10- and 20-week-old compost were characterized by high SOD-like and HRP-like activity, respectively. The concentration of phenolic compounds measured with HPLC in Trichoderma fungus culture VII from compost I corresponded with the decolorization degree and high HRP-like activity. The study results indicate that the genus Trichoderma with decolorization activity isolated from the first composting stages can be used in the biotransformation of post-industrial lignin waste.


Asunto(s)
Compostaje , Trichoderma , Residuos Industriales , Lignina
13.
Int Microbiol ; 23(2): 287-301, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31720871

RESUMEN

The study characterizes the anamorphic Bjerkandera adusta strain CCBAS 930, including growth conditions, physiological properties, and enzymatic activities related to basic metabolism and specific properties coupled with the fungal secondary metabolism. It was established that the fungus grows in a wide pH range (3.5-7.5), up to 3% of salt concentration and a temperature of 5-30 °C. Media rich in natural organic components (potato, maize extracts, whey) are optimal for biomass propagation. Minimal media, containing mineral salts and glucose as well as static growth conditions, are required to obtain idiophasic mycelium, equivalent to the secondary metabolism of the fungus. Of the 7 complex C, N, and energy sources tested, the strain did not utilize only fibrous cellulose. Lipolytic activity reached the highest values of the enzymatic activities corresponding to those capabilities. The specific properties of strain B. adusta CCBAS 930 determined by the production of HRP-like peroxidase were related to the decolorization and biodegradation of anthraquinone derivative daunomycin. The decolorization of 30% of daunomycin effluents occurred most rapidly in iso-osmotic medium and non-enriched with nitrogen, containing 0.25% glucose, pH = 5.0-6.0, and 25-30 °C. In agitated cultures, the strain decolorized solutions of daunomycin by biosorption, which coincided with the inhibition of aerial mycelium production and HRP-like biosynthesis. Based on knowledge, potential and real possibilities of using the strain in bioremediation of colored industrial sewage were discussed.


Asunto(s)
Biodegradación Ambiental , Coriolaceae , Daunorrubicina/metabolismo , Antineoplásicos/metabolismo , Coriolaceae/crecimiento & desarrollo , Coriolaceae/metabolismo , Residuos Industriales
14.
J Chromatogr Sci ; 2019 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-31800019

RESUMEN

The aim of this study was to develop a thin-layer chromatographic method of qualitative analysis, aiming to confirm the presence of the red beetroot pigments in a given sample. The TLC system developed for this purpose consists of the precoated RP-18 F254s TLC plates and the acetonitrile + methanol + water + glacial acetic acid, 2:7:1:0.1 (v/v/v/v) mobile phase. With the use of this system, a striking horizontal separation of betacyanin pigments is obtained for both the red beetroot juice and the commercial betanin sample (with the left-to-right resolution distance of the two bands equal to ca. 6 mm), and a unique pattern of the two skewed chromatographic bands is observed. This striking phenomenon has been given a thorough consideration, and its tentative physicochemical justification was provided, based on analogical cases reported and extensively discussed in our earlier studies. Characteristic fingerprint obtained both for the beetroot juice and the commercial sample of betanin (resembling two slant butterfly wings) can prove very helpful for qualitative confirmation of the presence (or otherwise) of the betanin pigment in the red color juices and beverages, as it was demonstrated upon an example of elderberry juice with a confirmed fortification with the betanin pigment.

15.
Sensors (Basel) ; 19(22)2019 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-31731676

RESUMEN

Designing electrical drives resistant to the failures of chosen sensors has recently become increasingly popular due to the possibility of their use in fault-tolerant control (FTC) systems including drives for electric vehicles. In this article, a virtual current sensor (VCS) based on an algorithmic method for the reconstruction of the induction motor (IM) phase currents after current sensor faults was proposed. This stator current estimator is based only on the measurements of the DC-bus voltage in the intermediate circuit of the voltage-source inverter (VSI) and a rotor speed. This proposal is dedicated to fault-tolerant vector controlled IM drives, where it is necessary to switch to scalar control as a result of damage to the current sensors. The proposed VCS allows further uninterrupted operation of the direct rotor-field oriented control (DRFOC) of the induction motor drive. The stator current estimator has been presented in the form of equations, enabling its practical implementation in a microprocessor system. Simulation studies of the proposed algorithm in an open and closed-loop DRFOC structure are presented under different operation conditions of the drive system. The experimental verification of the proposed method is also presented and the accuracy of the stator current estimation algorithm is analyzed under various operating conditions of the drive system.

16.
Artículo en Inglés | MEDLINE | ID: mdl-31276814

RESUMEN

The aim of the study was to compare cellular effects of xenobiotic cadmium and biogenic copper in ampullate silk glands of false black widow Steatoda grossa spider after long-term exposure via ingestion under laboratory conditions. Both the level of selected detoxification parameters (glutathione S-transferase, catalase, and the level of total antioxidant capacity) and degree of genotoxic changes (comet assay) were determined in the silk glands. Additionally the contents of selected amino acids (L-Ala, L-Pro, L-His, L-Phe, DL-Ile, and DL-Asn) in the hunting webs produced by spiders of this species were assessed. The ability of S. grossa females to accumulate cadmium was higher than that for copper. Long-term exposure of spiders to copper did not change the level of detoxification parameters, and the level of DNA damage in the cells of ampullate silk glands was also low. Cadmium had a stronger prooxidative and genotoxic effect than copper in the cells of the analyzed silk glands. However, regardless of the type of metal used, no significant changes in the level of amino acids in silk were found. The obtained results confirmed the effectiveness of metal neutralization mechanisms in the body of the studied spider species, which results in the protection of the function of ampullate silk glands.


Asunto(s)
Cadmio/toxicidad , Cobre/toxicidad , Glándulas Exocrinas/efectos de los fármacos , Arañas/efectos de los fármacos , Animales , Cadmio/metabolismo , Cobre/metabolismo , Daño del ADN , Glándulas Exocrinas/metabolismo , Femenino , Inactivación Metabólica , Arañas/genética , Arañas/metabolismo
17.
ISA Trans ; 93: 1-13, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30987804

RESUMEN

Induction machines have recently been very popular in variable-speed drives, because of their robust construction and relatively low manufacturing costs (brushless), maintenance-free and well-matured control methods. However, for high-precision control and efficiency optimization one needs the information on the rotor speed which can be measured using different speed sensors. All sensors require a mounting space and cabling, they also generate extra costs and reduce system reliability. Therefore, many of the recent research efforts have been dedicated to sensorless or encoderless electrical drives offering such considerable advantages as: lower cost, reduced size and hardware complexity of the drive system, elimination of sensor cables, lower maintenance requirements, possible operation in aggressive environment, higher noise immunity, reliable and user friendly operation. In this article all well-known sensorless techniques are shortly addressed, but the main focus is on the solutions based on the Model Reference Adaptive System (MRAS) concept. The mathematical models and schemes of all types of MRAS-type speed estimators known from the literature are gathered in this article. The comparative analysis of these speed estimators is done from the following points of view: the speed adaptation mechanism derivation based on the Lyapunov theory, stability problems near zero speed and in the regenerating operation mode, and the sensitivity of MRAS estimators to induction machine parameter changes.

19.
Int J Mol Sci ; 19(10)2018 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-30340353

RESUMEN

The endogenous pool of phytoregulators in plant tissues supplied with microbial secondary metabolites may be crucial for the development of winter wheat seedlings during cool springs. The phytohormones may be synthesized by psychrotrophic microorganisms in lower temperatures occurring in a temperate climate. Two fungal isolates from the Spitzbergen soils after the microscopic observations and "the internal transcribed spacer" (ITS) region molecular characterization were identified as Mortierella antarctica (MA DEM7) and Mortierella verticillata (MV DEM32). In order to study the synthesis of indoleacetic acid (IAA) and gibberellic acid (GA), Mortierella strains were grown on media supplemented with precursor of phytohormones tryptophan at 9, 15 °C, and 20 °C for nine days. The highest amount of IAA synthesis was identified in MV DEM32 nine-day-culture at 15 °C with 1.5 mM of tryptophan. At the same temperature (15 °C), the significant promoting effect (about 40% root and shoot fresh weight) of this strain on seedlings was observed. However, only MA DEM-7 had the ACC (1-aminocyclopropane-1-carboxylate) deaminase activity with the highest efficiency at 9 °C and synthesized IAA without tryptophan. Moreover, at the same conditions, the strain was confirmed to possess the strong promoting effect (about 40% root and 24% shoot fresh weight) on seedlings. Both strains synthesized GA in all tested terms and temperatures. The studied Mortierella strains had some important traits that led them to be considered as microbial biofertilizers components, improving plant growth in difficult temperate climates.


Asunto(s)
Liasas de Carbono-Carbono/biosíntesis , Giberelinas/biosíntesis , Ácidos Indolacéticos/metabolismo , Mortierella/fisiología , Plantones/crecimiento & desarrollo , Plantones/microbiología , Triticum/crecimiento & desarrollo , Triticum/microbiología , Ambiente , Reguladores del Crecimiento de las Plantas/metabolismo , Estaciones del Año , Microbiología del Suelo , Temperatura
20.
J Chromatogr A ; 1572: 137-144, 2018 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-30150119

RESUMEN

The aim of this study was to revisit the TLC authentication of alimentary products concept based on analysis of anthocyanes with the foodstuffs of plant origin. To this effect, we used two anthocyanins (cyanin and keracyanin) and two anthocyanidins (pelargonidin and delphinidin) as phytochemical standards. The first step was to develop a novel method making use of the RP-18 F254s stationary phase (which ensures mixed-mode retention mechanism with the localized adsorption on the non-bonded silanols) and acetic acid as the mobile phase component. Importantly, similar TLC systems are currently used for the analysis of anthocyanes. Individual steps of our method development enabled a deeper insight in vulnerability of anthocyanins to external conditions resulting in hydrolysis thereof. In this study, it was impossible to fully separate the products of hydrolytic degradation of the test anthocyanins in a single development run and it was only triple development which ensured distinct and symmetrically shaped chromatographic spots, further scrutinized with use of mass spectrometry. The identity of the hydrolytically split fractions was additionally studied with use of the p-aminobenzoic acid (PABA) test. To obtain calibration curves, triple development was employed for cyanin, keracyanin, and pelargonidin, while delphinidin was developed in one development run. The respective LOD and LOQ values were: for spot (i) derived from the cyanin standard, 0.005 and 0.016 µg spot-1; for spot (ii) derived from the cyanin standard, 0.006 and 0.017 µg spot-1; for spot (i) derived from the keracyanin standard, 0.092 and 0.274 µg spot-1; for spot (ii) derived from the keracyanin standard, 0.035 and 0.104 µg spot-1; for the pelargonidin standard, 0.013 and 0.040 µg spot-1; and for the delphinidin standard, 0.036 and 0.108 µg spot-1. The developed method was used to identify and quantify cyanin, keracyanin, pelargonidin and delphinidin in selected alimentary products (syrups, juices and herbal infusions), keeping in mind that the obtained numerical results were of semi-quantitative nature only.


Asunto(s)
Antocianinas/análisis , Cromatografía en Capa Delgada/métodos , Ácido 4-Aminobenzoico/química , Antocianinas/aislamiento & purificación , Densitometría , Jugos de Frutas y Vegetales/análisis , Límite de Detección , Espectrometría de Masas
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