Search results for "design."
showing 10 items of 5715 documents
Justification of Construction Parameters of the Screen in the Small-Sized Household Biomass Chopper
2019
The mechanism of influence of screen design parameters on the technological process and the particle size distribution of the chopped biomass were determined in this research. The presented engineering solutions make it possible to design the screen for chopping the given biomass material. The modernized construction expands the scope of application of small-sized chopper, especially when used in private farm households. Size control of the chopped material allows to use material as fuel, material for mulching of berry plantations and gardens, material for production of constructional and insulating wood concrete.
Processing of Generator-Produced 68Ga for Medical Application
2007
The (68)Ge/(68)Ga generator provides an excellent source of positron-emitting (68)Ga. However, newly available "ionic" (68)Ge/(68)Ga radionuclide generators are not necessarily optimized for the synthesis of (68)Ga-labeled radiopharmaceuticals. The eluates have rather large volumes, a high concentration of H(+) (pH of 1), a breakthrough of (68)Ge, increasing with time or frequency of use, and impurities such as stable Zn(II) generated by the decay of (68)Ga, Ti(IV) as a constituent of the column material, and Fe(III) as a general impurity.We have developed an efficient route for the processing of generator-derived (68)Ga eluates, including the labeling and purification of biomolecules. Prec…
Negative pressure cavitation accelerated processing for extraction of main bioactive flavonoids from Radix Scutellariae
2011
Abstract To enhance the extraction efficiency and reduce the energy consumption, an emerging technology named negative pressure cavitation extraction (NPCE) has been shown to be a feasible option for the extraction of bioactive compounds in agricultural crops and medicinal plants. Meanwhile, it can be applied at the pilot scale as a manufacturing process for edible and medicinal plants. Currently, NPCE was proposed for extraction of baicalin, wogonoside, baicalein and wogonin from Radix Scutellariae on the basis of a central composite design (CCD) and response surface methodology (RSM). With proper optimization (80 mesh of particle size, 40 mL/g of liquid/solid ratio, 75% aqueous ethanol as…
Enhanced extraction of isoflavonoids from Radix Astragali by incubation pretreatment combined with negative pressure cavitation and its antioxidant a…
2011
Abstract Incubation pretreatment with the function of endogenous enzyme combined with negative-pressure cavitation extraction (IP-NPCE) was established to extract calycosin and formononetin from Radix Astragali. Significant factors involved in the process were selected using Plackett–Burman factorial design (PBD) and then were optimized by central composite design (CCD). The optimum experimental conditions were incubation at 35 °C, 60 min, pH 4.0 and extraction at negative pressure − 0.080 MPa, ethanol concentration 60%, 60 mesh, 30 min, solid-to-liquid ratio 1:25 and two cycles. Under the optimal conditions, the extraction yields of calycosin and formononetin were 0.650 ± 0.015 and 0.307 ±…
Dynamic reaction cell inductively couple plasma-mass spectrometry optimization for seawater analysis
2018
Abstract A direct method for dynamic reaction cell inductively coupled plasma- mass spectrometry (DRC-ICP-MS) trace mineral elements determination in seawater was optimized by Experimental Statistical Design. Five instrumental parameters, such as radiofrequency, sample, nebulizer and reaction gas flows, rejection parameter q and axial field voltage were studied. A Plackett-Burman design was used for screening the most important parameters and the most significant ones were optimized with a Central composite design. Fifteen elements and different isotopes for some of these were considered through the study. The optimization was achieved by using three different reaction gases (NH3, CH4 and O…
Negative pressure cavitation extraction and antioxidant activity of genistein and genistin from the roots of pigeon pea [Cajanus cajan (L.) Millsp.]
2010
Abstract A new method—negative pressure cavitation extraction (NPCE) was proposed and investigated for the extraction of the main isoflavonoids, namely genistein and genistin from pigeon pea roots. The effects of extraction time and particle size on the extraction yields were firstly optimized, then a central composite design (CCD) combined with response surface methodology (RSM) was used to study the effects of negative pressure, ethanol concentration and liquid/solid ratio on the extraction yields. The maximum extraction yields of genistein and genistin reached 0.418 and 0.398 mg/g, respectively, under the optimal conditions: extraction time 45 min, particle size 50 mesh, negative pressur…
Enzymatic water extraction of taxifolin from wood sawdust of Larix gmelini (Rupr.) Rupr. and evaluation of its antioxidant activity
2011
Abstract An enzyme incubation–water extraction (EI–WE) method was developed and optimised for the extraction of the natural antioxidant taxifolin and of the total flavonoids from wood sawdust of Larix gmelini ( Rupr. ) Rupr. A factorial design and a central composite design approach were used for method optimisation. Optimal conditions were 0.5 mg/ml cellulase and 0.5 mg/ml pectinase, a pH of 5.0, a temperature of 32 °C and 18 h incubation time. The flavonoids and taxifolin were extracted in hot water at 50 °C for 30 min, with a solid to liquid ratio of 1:20. Under optimised conditions, the yields of taxifolin and total flavonoids increased from 1.06 ± 0.08 to 1.35 ± 0.04 mg/g and 4.13 ± 0.…
Determination of major human cytochrome P450s activities in 96-well plates using liquid chromatography tandem mass spectrometry.
2007
At the early stage of drug discovery, thousands of new chemical entities (NCEs) may be screened before a single candidate can be identified for development. Evaluation of the effect of NCEs on human CYP450 enzyme activities is a key issue in pharmaceutical development as it may explain inter-subject variability, drug-drug interactions, non-linear pharmacokinetics and toxic effects. A liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method has been developed for the fast and routine analysis of major human CYP450s enzyme activities (CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4) in primary hepatocyte cell cultures. The high sensitivity and selectivity of mass …
Novel insights into excipient effects on the biopharmaceutics of APIs from different BCS classes: Lactose in solid oral dosage forms
2014
Excipients encompass a wide range of properties that are of importance for the resulting drug product. Regulatory guidelines on biowaivers for immediate release formulations require an in depth understanding of the biopharmaceutic effects of excipients in order to establish bioequivalence between two different products carrying the same API based on dissolution tests alone. This paper describes a new approach in evaluating biopharmaceutic excipient effects. Actually used quantities of a model excipient, lactose, formulated in combination with APIs from different BCS classes were evaluated. The results suggest that companies use different (relative) amounts depending on the characteristics o…
Separation of the enantiomers of primary and secondary amphetamines by liquid chromatography after derivatization with (−)-1-(9-fluorenyl)ethyl chlor…
2003
The chiral reagent (−)-1-(9-fluorenyl)ethyl chloroformate (FLEC) has been evaluated for the enantioselective analysis of amphetamines by liquid chromatography. For separation of the FLEC diastereomers conventional reversed-phase conditions were used. The conditions affording the best enantiomeric resolution and sensitivity were determined for amphetamine, methamphetamine, ephedrine, pseudoephedrine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDE). All the amphetamines assayed could be separated with resolution factors ranging from 0.91 to 1.92. Although FLEC is typically used as a fluorogenic reagent, it was shown t…