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371.
The nonionogenic pyrene-based tenside, poly(ethylene glycol) pyrenebutanoate, was prepared and applied in capillary isoelectric focusing with fluorometric detection. This dye was used here as a buffer additive in capillary isoelectric focusing for a dynamic modification of the sample of proteins and microorganisms. The values of the isoelectric points of the labeled bioanalytes were calculated with use of the fluorescent pI markers and were found comparable with pI of the native compounds. The mixed cultures of proteins and microorganisms, Escherichia coli CCM 3954, Staphylococcus epidermidis CCM 4418, Proteus vulgaris, Enterococcus faecalis CCM 4224, and Stenotrophomonas maltophilia, the strains of the yeast cells, Candida albicans CCM 8180, Candida krusei, Candida parapsilosis, Candida glabrata, Candida tropicalis, and Saccharomyces cerevisiae were reproducibly focused and separated by the suggested technique. Using UV excitation for the on-column fluorometric detection, the minimum detectable amount was down to 10 cells injected on the separation capillary. 相似文献
372.
Nanoparticles (NPs) have an outstanding position in pharmaceutical, biological, and medical disciplines. Polymeric NPs based on chitosan (CS) can act as excellent drug carriers because of some intrinsic beneficial properties including biocompatibility, biodegradability, non-toxicity, bioactivity, easy preparation, and targeting specificity. Drug transport and release from CS-based particulate systems depend on the extent of cross-linking, morphology, size, and density of the particulate system, as well as physicochemical properties of the drug. All these aspects have to be considered when developing new CS-based NPs as potential drug delivery systems. This comprehensive review is summarizing and discussing recent advances in CS-based NPs being developed and examined for drug delivery. From this point of view, an enhancement of CS properties by its modification is presented. An enhancement in drug delivery by CS NPs is discussed in detail focusing on (i) a brief summarization of basic characteristics of CS NPs, (ii) a categorization of preparation procedures used for CS NPs involving also recent improvements in production schemes of conventional as well as novel CS NPs, (iii) a categorization and evaluation of CS-based-nanocomposites involving their production schemes with organic polymers and inorganic material, and (iv) very recent implementations of CS NPs and nanocomposites in drug delivery. 相似文献
373.
Veronika Veits und Harald Rohm 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,189(6):544-549
Zusammenfassung Die Suche nach Referenzbeispielen für geometrische und sonstige Textureigenschaften sowie die Erstellung von Definitionen deskriptiver Texturbegriffe erfordert eine terminologische Anpassung aufgrund semantischer Inkongruenzen und die Berücksichtigung regionaler Konsumgewohnheiten. Ein geschultes Prüferpanel erarbeitete durch diskussionsunterstützte Prüfung von Produktbeispielen eine repräsentative Auswahl an texturellen Termini und entsprechenden Definitionen. Zwei Basistexturprofile illustrieren die erfolgreiche Umsetzung der Texturprofilanalyse.
Adaption of texture profile analysis 2. Geometrical and other properties —basic texture profiles
Summary To describe geometrical and other texture properties, an adequate selection of reference materials, accompanied by a definition of textural terms, is necessary. Adaptation of terminology for semantic reasons is required, as well as consideration of regional habits of consumption. The work of a trained panel in testing some food materials, supported by discussion, resulted in a representative creation of texture terms and definitions. Basic texture profiles illustrate the successful transformation of texture profile analysis.相似文献
374.
Monika Hud
ov Slvka Hamuakov Eva Konkoov Rastislav Jendelovský Jana Vargov Juraj evc Peter Fedoro
ko Ondrej Soukup Jana Jano
kov Veronika Ihnatova Tom Ku
era Petr Bzonek Nikola Novakova Daniel Jun Lucie Junova Jan Korbe
ný Kamil Ku
a Mria Kourkov 《International journal of molecular sciences》2021,22(8)
A series of novel C4-C7-tethered biscoumarin derivatives (12a–e) linked through piperazine moiety was designed, synthesized, and evaluated biological/therapeutic potential. Biscoumarin 12d was found to be the most effective inhibitor of both acetylcholinesterase (AChE, IC50 = 6.30 µM) and butyrylcholinesterase (BChE, IC50 = 49 µM). Detailed molecular modelling studies compared the accommodation of ensaculin (well-established coumarin derivative tested in phase I of clinical trials) and 12d in the human recombinant AChE (hAChE) active site. The ability of novel compounds to cross the blood–brain barrier (BBB) was predicted with a positive outcome for compound 12e. The antiproliferative effects of newly synthesized biscoumarin derivatives were tested in vitro on human lung carcinoma cell line (A549) and normal colon fibroblast cell line (CCD-18Co). The effect of derivatives on cell proliferation was evaluated by MTT assay, quantification of cell numbers and viability, colony-forming assay, analysis of cell cycle distribution and mitotic activity. Intracellular localization of used derivatives in A549 cells was confirmed by confocal microscopy. Derivatives 12d and 12e showed significant antiproliferative activity in A549 cancer cells without a significant effect on normal CCD-18Co cells. The inhibition of hAChE/human recombinant BChE (hBChE), the antiproliferative activity on cancer cells, and the ability to cross the BBB suggest the high potential of biscoumarin derivatives. Beside the treatment of cancer, 12e might be applicable against disorders such as schizophrenia, and 12d could serve future development as therapeutic agents in the prevention and/or treatment of Alzheimer’s disease. 相似文献
375.
Vera Sovkova Karolina Vocetkova Vra Hedvi
kov Veronika Hefka Blahnov Matj Buzgo Evzen Amler Eva Filov 《International journal of molecular sciences》2021,22(9)
Platelet concentrates and especially their further product platelet lysate, are widely used as a replacement for cell culturing. Platelets contain a broad spectrum of growth factors and bioactive molecules that affect cellular fate. However, the cellular response to individual components of the human platelet concentrate is still unclear. The aim of this study was to observe cellular behavior according to the individual components of platelet concentrates. The bioactive molecule content was determined. The cells were supplemented with a medium containing 8% (v/v) of platelet proteins in plasma, pure platelet proteins in deionized water, and pure plasma. The results showed a higher concentration of fibrinogen, albumin, insulin growth factor I (IGF-1), keratinocyte growth factor (KGF), and hepatocyte growth factor (HGF), in the groups containing plasma. On the other hand, chemokine RANTES and platelet-derived growth factor bb (PDGF-bb), were higher in the groups containing platelet proteins. The groups containing both plasma and plasma proteins showed the most pronounced proliferation and viability of mesenchymal stem cells and fibroblasts. The platelet proteins alone were not sufficient to provide optimal cell growth and viability. A synergic effect of platelet proteins and plasma was observed. The data indicated the importance of plasma in platelet lysate for cell growth. 相似文献
376.
Leonard Jacques Veronika Kovacova Jung In Yang Susan Trolier-McKinstry 《Journal of the American Ceramic Society》2021,104(10):4968-4976
Potassium sodium niobate (KNN) thin films are potentially useful for energy harvesting devices and for lead-free piezoelectric microelectromechanical systems. This work reports the activation energies for nucleation, growth and perovskite phase transformation from a 0.5% manganese-doped KNN 2-methoxyethanol-based solution modified with acetylacetone and excess alkali precursors. The films were annealed in a rapid thermal processor (RTP) with a hold step at temperatures from 500 to 550°C. The activation energies for perovskite transformation and growth, determined by electron micrograph observation, were 687 ± 13 and 194 ± 10 kJ/mol. The activation energy for nucleation was 341 ± 20 kJ/mol. Based on these data, crystallization in KNN is found to be nucleation-limited; thus, it should be possible to reduce the crystallization temperature by utilizing a seed layer which provides nucleation sites, provided the organics are removed from the film. 相似文献
377.
Veronika Lang und Gerhard Wildbrett 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,188(3):243-247
Zusammenfassung Die quantitative Bestimmung von Stärke mit Anthron eignet sich dazu, geringe Stärkereste auf maschinell gespültem Geschirr zu erfassen. Die Methode ist gleichermaßen anwendbar auf native Kartoffelstärke als auch auf deren Derivate in Form von kaltlöslicher Stärke, Distärkephosphat, kaltquellendem Stärkeacetat und oxidativ modifizierter Stärke. Die ermittelten Eichkurven sind bis 300 g/ml linear. Die untere Bestimmungsgrenze liegt bei 2,6 g/ml Stärke. Sowohl die alkalische Stärke- als auch die Anthronlösung bleibt bei Raumtemperatur bis zu 5 Tagen stabil.
A method for the determination of native and modified starches on dishes cleaned by dish-washers
Summary The quantitative determination of starch with anthrone has been used to determine minimal residues of starch on dishes cleaned by dishwashers. The method can also be applied to the determination of native starch in potatoes as well as in derivatives such as cold water soluble starch, with ionic phosphate groups cross-linked starch, starch acetates swelling in cold water and of oxidative modified starch. The standard curves are linear, up to 300 g/ml dissolved starch. The lowest concentration of starch that can be determined by the method is 2.6 g/ml. Both the alkaline starch solution and the anthrone reagent remain stable up to 5 days at ambient temperature.相似文献
378.
Boettler U Volz N Pahlke G Teller N Kotyczka C Somoza V Stiebitz H Bytof G Lantz I Lang R Hofmann T Marko D 《Molecular nutrition & food research》2011,55(5):798-802
Recently, the coffee constituents 5-O-caffeoylquinic acid (CGA) and N-methylpyridinium (NMP) were identified as inducers of the Nrf2/antioxidant-response element (ARE) detoxifying pathway under cell-culture condition. To study the impact of CGA and NMP on the Nrf2-activating properties of a complex coffee beverage, two different model coffees were generated by variation of the roasting conditions: a low-roast coffee rich in CGA and a heavy-roast low in CGA but containing high levels of NMP. Activation of the Nrf2/antioxidant-response element pathway was monitored in vitro and in vivo. 相似文献
379.
Kotyczka C Boettler U Lang R Stiebitz H Bytof G Lantz I Hofmann T Marko D Somoza V 《Molecular nutrition & food research》2011,55(10):1582-1586
Recent results from prospective cohort studies have shown that moderate coffee consumption is associated with a reduced risk for diabetes mellitus type II or Alzheimer's disease. Since reactive oxygen species (ROS) are believed to be involved in the pathogenesis of these diseases, antioxidants in coffee might contribute to this risk reduction. We aimed at elucidating whether a dark roast coffee beverage (CB) rich in N‐methylpyridinium ions (NMP: 785 μmol/L) and low in chlorogenic acids (CGA: 523 μmol/L) has stronger antioxidant effects on human erythrocytes than a CB prepared from a light roast with opposite proportions (CGA: 4538 μmol/L; NMP: 56 μmol/L). Following a 2‐wk wash out period, 500 mL of the respective CB was administered to 30 subjects daily for 4‐wk. Blood and spot urine samples were collected at the beginning and at the end of each intervention. Intake of the dark roast CB most effectively improved the antioxidant status of erythrocytes: superoxide dismutase and glutathione peroxidase activity decreased by 5.8 and 15%, respectively, whereas tocopherol and total glutathione concentrations increased by 41 and 14%, respectively. Furthermore, administration of the NMP‐rich CB led to a significant body weight reduction in pre‐obese subjects, whereas the CGA‐rich CB did not. 相似文献
380.
The electrical conductance G of mechanical break-junctions fabricated from the rare-earth metal dysprosium has been investigated at 4.2 K where Dy is in the ferromagnetic state. In addition to the usual variation of the conductance while breaking the wire mechanically, the conductance can be changed reproducibly by variation of the magnetic field H, due to the large magnetostriction of Dy. For a number of contacts, we observe discrete changes in G(H) in the range of several G(0) = 2e(2)/h. The behavior of G(H) and its angular dependence can be quantitatively understood by taking into account the magnetostrictive properties of Dy. This realization of a magnetostrictive few-atom switch demonstrates the possibility of reproducibly tuning the conductance of magnetic nanocontacts by a magnetic field. 相似文献