Search results for "Bt"
showing 10 items of 1498 documents
Hyperbolic subtraction method: Determination of the concentration of an analyte in the presence of an unknown interferent via spectral data.
2018
A theoretical model to determine the concentration of an analyte in the presence of unknown interferents using spectral-type data is described. The method involves absorbance measurements at three wavelengths and the calculation of specific absorbances yielding a hyperbolic relationship between absorbance ratios and analyte concentrations. The concentration of the analyte of known spectrum can be determined in the presence of an interferent or mixture of interferents of unknown concentration(s) and spectra can be determined combining data for different sets of wavelengths. Application to indigo and isatin solutions in DMSO related to the so-called Maya blue problem is reported as an illustr…
Headspace–mass spectrometry determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers in soil samples using chemometrics
2007
A simple and fast method has been developed for the determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers (BTEX) in soils. Samples were introduced in 10 mL standard glass vials of a headspace (HS) autosampler together with 150 microL of 2,6,10,14-tetramethylpentadecane, heated at 90 degrees C for 10 min and introduced in the mass spectrometer by using a transfer line heated at 250 degrees C as interface. The volatile fraction of samples was directly introduced into the source of the mass spectrometer which was scanned from m/z 75 to 110. A partial least squares (PLS) multivariate calibration approach based on a classical 3(3) calibration model was build with m…
An improved numerical solver of the 2D diffusive shallow waters equations over unstructured triangular meshes
2009
Personīgo zināšanu pārvaldības iespējas ar mobilā telefona lietotnes palīdzību
2018
Pasaule ir ļoti sarežģīti aptverama un izzināma vieta. Ikdienā cilvēki uztver ļoti daudz informācijas, kas netiek organizēta. Personīgo zināšānu pārvaldība palīdz saprast, kas ir svarīgs, pārvietot informāciju un organizēt to, lai tiktu galā ar problēmām, kas izveidojas, prasot risinājumu. Darbā tiek apskatītas esošās pieejas – modeļi, sistēmas. Lai risinātu šo problēmu, tiek apskatīts veids, kā izstrādāt Android telefonu lietotni, kas izmantojot personības testu, nosaka ar personību saistītos atslēgvārdus, lai iegūt datus no kāda avota un izmanto NLP metodes, lai pakārtotu informāciju, kas palīdzētu iegūt konkrētam indivīdam būtisku informāciju.
Use of electron spectroscopic imaging to determine element composition of the melanin granules in the stria vascularis of the guinea pig.
1998
Electron spectroscopic imaging (ESI) was used to analyze the element content of melanin granules in the stria vascularis seen in ultrathin sections of Spurr-embedded cochleae of the guinea pig. To determine element composition, ESI images were taken at different ionization edges, and non-specific background signals were subtracted digitally by an image processing system. The presence of calcium and nitrogen in the melanin granules could be demonstrated clearly. The calcium identified in the melanin granules was then compared with the spatial distributions of calcium binding sites after the application of an antimonate precipitation method, which was used to localize loosely bound calcium. D…
Evaluation of the antioxidant capacity, furan compounds and cytoprotective/cytotoxic effects upon Caco-2 cells of commercial Colombian coffee.
2017
Abstract Antioxidant capacity (AC), total phenolics (TPs), furan compounds (HMF and furfural F) and cytoprotective/cytotoxic effects upon Caco-2 cells (MTT, cell cycle and reactive oxygen species (ROS)) were evaluated in Colombian coffee (2 ground and 4 soluble samples). The AC (ABTS and FRAP), TPs and HMF ranged between 124–722, 95–802 μmoles Trolox/g, 21–100 mg gallic acid/g and 69–2900 mg/kg, respectively. Pretreatment of cells for 24 h with lyophilized coffee infusions at the highest dose without cytotoxic effects (500 μg/mL) significantly prevented the decrease in cell viability compared to control stress with H2O2 (5 mM/2 h), recovering viability to values between 34% and 45% and rest…
Negative-pressure cavitation extraction of cajaninstilbene acid and pinostrobin from pigeon pea [Cajanus cajan (L.) Millsp.] leaves and evaluation of…
2011
Abstract In this study, an efficient negative-pressure cavitation extraction (NPCE) technique was developed to extract cajaninstilbene acid (CSA) and pinostrobin (PI) from pigeon pea [Cajanus cajan (L.) Millsp.] leaves. The operating parameters were optimised using single-factor experiment and central composite design combined with response surface methodology. Well-fitting models for the extraction of CSA and PI were successfully established. From the economic perspective, the selected operating parameters were: extraction pressure −0.075 MPa, extraction temperature 45 °C, material size 40 mesh, ethanol concentration 80%, extraction time 30 min, liquid/solid ratio 30:1 and 4 extraction cyc…
Potential in vitro antioxidant, anti-inflammatory, antidiabetic, and anticancer effect of arachidonic acid-elicited basil leaves
2017
Abstract The study presents the impact of elicitation of basil with 0.01 µM (AA1), 1 µM (AA2) and 100 µM (AA3) arachidonic acid on the content and bioactivity of potentially bioavailable polyphenols. Elevated levels of phenolic compounds correlated with increased biological activity were observed in the extracts from basil (control and elicited) subjected to simulated gastrointestinal digestion in comparison to chemical and standard buffer extracts. Elicitation with AA1 and AA2 resulted in an 3-fold and more than 4-fold increase in the content of potentially bioavailable rosmarinic acid, respectively. In some cases, elicitation with arachidonic acid improved the pro-health properties of the…
Phytochemical profile and antioxidative properties of Plinia trunciflora fruits: A new source of nutraceuticals.
2020
Abstract This study evaluated the polyphenol profile and the antioxidative properties of Plinia trunciflora (O. Berg) Kausel fruits. Folin-Ciocalteau and pH-jumping methods indicated that these berries are a major source of antioxidant polyphenols (1201.05 mg GAE/100 g FW), particularly anthocyanins. HPLC-DAD-ESI-MS/MS analysis identified cyanidine glycosides as the main components. Flavon-3-ols and hydrolysable-tannins were also found. CAA assay showed that extracts of P. trunciflora fruits prevent lipid peroxidation in HepG2 cells with higher efficacy than other colourful fruits (CAA50 935.25 mg FW/mL cell medium). Moreover, our results suggested that the observed antioxidant protection i…
Bioactive components of caper (Capperis spinosa L.) from Sicily and antioxidant effects in a red meat simulated gastric digestion
2007
An increasing body of evidence on the association between adherence to the Mediterranean diet and healthy status is being accumulated. Floral buds of Capparis spinosa L. are commonly used in the Mediterranean cuisine as flavoring for meat and other foods. The present study evaluated bioactive components and antioxidant activity of Sicilian capers stabilized in salt. Whereas alpha-tocopherol was absent, low levels of gamma-tocopherol and vitamin C were measured. With reference to one serving size (8.6 g of capers), rutin was 13.76 mg, isothiocyanates, recently acknowledged as anticarcinogen phytochemicals, were 42.14 micromol, total phenols were 4.19 mg of gallic acid equivalents (GAE), and …