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61.
62.
Dr. Sebastian Meier Dr. Natalia Solodovnikova Dr. Pernille R. Jensen Prof. Jürgen Wendland 《Chembiochem : a European journal of chemical biology》2012,13(15):2265-2269
Detecting the molecular targets of xenobiotic substances in vivo poses a considerable analytical challenge. Here, we describe the use of an NMR‐based tracer methodology for the instantaneous in vivo observation of sulfur(IV) action on cellular metabolism. Specifically, we find that glycolytic flux is directed towards sulfite adducts of dihydroxyacetone phosphate and pyruvate as off‐pathway intermediates that obstruct glycolytic flux. In particular, the pyruvate–sulfite association hinders the formation of downstream metabolites. The apparent in vivo association constant of pyruvate and sulfite agrees with the apparent inhibition constant of CO2 formation, thus supporting the importance of pyruvate interception in disturbing central metabolism and inhibiting NAD regeneration. 相似文献
63.
The present paper describes the synthesis of silica nanoparticles via the sol–gel method assisted by reverse micelle microemulsion, using reagents as Triton x-100/Cyclohexane/Methanol/H2O, and also the effect on particle size of some synthesis parameters such as the water-surfactant molar ratio (R), Co-surfactant-surfactant (ρ), and synthesis time (t). The structure, morphology, and size of the silica nanoparticles were characterized with transmission electron microscopy and scanning electron microscopy. A variation of ρ = [Methanol]/[Triton X-100] affects the size, morphology, and dispersion of the particles. An increase in the concentration of methanol produces a decrease in particle size. The condition that resulted in smaller particle size, better spherical morphology, and monodispersity was when ρ = 7.6, which generated an approximate size of 83 ± 7 nm. The parameter R = [H2O]/[Triton X-100] affects not only the size of the particles, but also their morphology. Higher values of R result in a decrease in the amount of catalyst present in the interior of the micelle, but in turn generate a greater amount of water, which results in a decrease in particle size and polydispersity. Time is a parameter that directly affects the size of the silica particles. The optimal time for the synthesis of nanoparticles was 2 h, resulting in silica nanoparticles of 25 ± 3 nm, monodisperse, with spherical morphology and without the presence of agglomerations. 相似文献
64.
Korzeniewski Dariusz Znojkiewicz Natalia 《Journal of Mechanical Science and Technology》2021,35(7):2879-2884
Journal of Mechanical Science and Technology - The work concerns the assessment of the parameters of the geometric structure of the surface of an aluminum-ceramic composite after milling in various... 相似文献
65.
Natalia Vassileva Yevgeni Koucheryavy 《Wireless Communications and Mobile Computing》2015,15(4):666-684
The adaptive modulation and coding (AMC) technique, which has been adopted by advanced mobile telecommunication systems, supports a flexible response to the random radio behaviour. As a result, the attained transmission rate over a wireless link is time varying. Hence, resource demands are not deterministic but fluctuating even for calls with constant bit rate service requirements. Consequently, constant bit rate calls are susceptible to a forced call termination because of insufficient resources not only in a target cell during inter‐cell handoffs but also in a serving cell during radio link deterioration. Furthermore, call blocking and dropping probabilities depend on radio propagation conditions among other factors and therefore they are dissimilar throughout a service area. The latter leads to unfairness problems. We analytically measure the impact of AMC on fixed‐rate service with hard delay constraints such as voice for different signal, mobility and traffic conditions. We consider a reference case (call requests are admitted into the system provided there are enough free resources) and two classes of admission control approaches: traditional (only inter‐cell handoffs are prioritised) and modified (all ongoing calls are prioritised). The reported results reveal conditions for which AMC affects voice call performance and can serve as guidelines on admission control design. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
66.
Natalia Remirez de Esparza Nerea Cocera Lexuri Vazquez Jon Alkorta Ibon Ocaña Jose M. Sanchez 《Journal of the American Ceramic Society》2014,97(12):3958-3966
The oxidation of highly porous ceramic matrix composites (PCMCs) based on different Tyranno® fibers has been analyzed by means of thermogravimetry and electron microscopy. Both uncoated fibers and PCMC materials exhibit parabolic kinetics between 900°C and 1250°C, these being faster for Ti‐doped than for Zr‐doped Tyranno fibers. Oxide layers in Ti‐doped fibers are porous and partially crystalline, whereas in Zr‐doped materials a significant fraction of relatively coarse β‐SiC grains is still found embedded in the amorphous silica matrix. On the other hand, the CVD‐SiC coatings exhibit higher oxidation rates from the outer surface than from the inner one, a phenomenon that has been associated not only with the more difficult access of oxygen to the inner face but also with the highly <111> textured structure of these coatings, for which very different oxidation rates have been published for the inward and outward directions. Cracking phenomena observed above 1100°C for long dwelling times do not lead to an acceleration of the oxidation process, which could be due to the simultaneous crystallization of the amorphous silica layers. 相似文献
67.
The aim of the present work was to develop two products from blackberry juice by freeze and spray drying with potential use as food colorants or healthy ingredients. A characterization of the physical and functional properties of the powdered juices was done. Maltodextrin or a mixture of trehalose and maltodextrin were assessed as carrier matrices. Freeze-dried, maltodextrin-containing powders presented the best retention of bioactive compounds and antiradical activity; however, they showed a narrow relative humidity range for storage in the glassy state. Spray-dried powders showed better physical properties, bearing higher glass transition temperature and lower molecular mobility than freeze-dried formulations. 相似文献
68.
Alena Sergeeva Natalia Feoktistova Vladimir Prokopovic Dmitry Gorin Dmitry Volodkin 《Advanced Materials Interfaces》2015,2(18)
Fabrication of porous alginate hydrogels with a well‐controlled architecture useful for tissue engineering is still a challenge. Here, CaCO3‐based templating is utilized to design stable alginate gels with controlled pore dimensions in the range of 5–50 μm. The mechanism of pore formation is studied considering two factors affecting the pore size: i) osmotic pressure generated during the dissolution of sacrificial CaCO3 templates and ii) alginate gel network density. Osmotic pressure can achieve an upper limit of 100 MPa but does not affect the gel porosity. Additional osmotic pressure (range of kPa) induced by dextrans pre‐encapsulated into CaCO3 vaterite is also insufficient for pore enlargement. Pore stability depends merely on the gel network density and on the number of crosslinking calcium ions provided locally per unit time; pores are collapsed when template dissolution is too slow or if there is insufficient alginate concentration (below 2%). Young's modulus indicates the soft nature of the prepared hydrogels (tens of kPa) applicable as soft porous scaffolds with a tuned internal structure. 相似文献
69.
Pablo J. Giraudi Noel Salvoza Deborah Bonazza Carlo Saitta Daniele Lombardo Biagio Casagranda Nicol de Manzini Teresa Pollicino Giovanni Raimondo Claudio Tiribelli Silvia Palmisano Natalia Rosso 《International journal of molecular sciences》2022,23(5)
Fibrosis is the strongest predictor for disease-specific mortality in non-alcoholic fatty liver diseases (NAFLD), but the need for liver biopsy limits its diagnosis. We assessed the performance of plasma ficolin-2 (FCN-2) as a biomarker of fibrosis identified by an in silico discovery strategy. Two hundred and thirty-five morbidly obese (MO) subjects with biopsy-proven NAFLD stratified by fibrosis stage (F0, n = 44; F1, n = 134; F2, n = 46; F3/F4, n = 11) and 40 cirrhotic patients were enrolled. The cohort was subdivided into discovery (n = 76) and validation groups (n = 159). The plasma level of FCN-2 and other candidate markers was determined. FCN-2 was inversely correlated with the stage of liver fibrosis (ρ = −0.49, p < 0.001) independently of steatosis (p = 0.90), inflammation (p = 0.57), and ballooning (p = 0.59). In the global cohort, FCN-2 level decreased significantly in a stepwise fashion from F0/F1 (median 4753 ng/mL) to F2–F3–F4 (2760 ng/mL) and in cirrhotic subjects (1418 ng/mL). The diagnostic performance of FCN-2 in detecting F ≥ 2 was higher than other indexes (APRI, FIB-4) (AUROC 0.82, 0.68, and 0.6, respectively). The accuracy improved when combined with APRI score and HDL values (FCNscore, AUROC 0.85). Overall, the FCN-2 plasma level can accurately discriminate liver fibrosis status (minimal vs. moderate/advanced) significantly improving the fibrosis diagnostic algorithms. 相似文献
70.
Natalia V. Pozdniakova Oxana V. Ryabaya Alevtina S. Semkina Vsevolod A. Skribitsky Alexei B. Shevelev 《International journal of molecular sciences》2022,23(6)
Three artificial proteins that bind the gadolinium ion (Gd3+) with tumour-specific ligands were de novo engineered and tested as candidate drugs for binary radiotherapy (BRT) and contrast agents for magnetic resonance imaging (MRI). Gd3+-binding modules were derived from calmodulin. They were joined with elastin-like polypeptide (ELP) repeats from human elastin to form the four-centre Gd3+-binding domain (4MBS-domain) that further was combined with F3 peptide (a ligand of nucleolin, a tumour marker) to form the F3-W4 block. The F3-W4 block was taken alone (E2-13W4 protein), as two repeats (E1-W8) and as three repeats (E1-W12). Each protein was supplemented with three copies of the RGD motif (a ligand of integrin αvβ3) and green fluorescent protein (GFP). In contrast to Magnevist (a Gd-containing contrast agent), the proteins exhibited three to four times higher accumulation in U87MG glioma and A375 melanoma cell lines than in normal fibroblasts. The proteins remained for >24 h in tumours induced by Ca755 adenocarcinoma in C57BL/6 mice. They exhibited stability towards blood proteases and only accumulated in the liver and kidney. The technological advantages of using the engineered proteins as a basis for developing efficient and non-toxic agents for early diagnosis of tumours by MRI as well as part of BRT were demonstrated. 相似文献