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91.
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93.
The physicochemical and catalytic properties of phosphorus-promoted H-ultrasils were examined in the disproportionation of ethylbenzene. It was shown that the chemical modification of H-ultrasil with ammonium hydrogen phosphate leads to the redistribution of acid sites and a decrease in the sorption capacity of the zeolite. As a result, the ratio between Lewis and Brönsted acid sites in the zeolite increases in a more pronounced manner and zeolite channels narrow, thereby enhancing the paraselectivity for isomers. 相似文献
94.
Alan A. Akhmedov Dmitriy N. Shurpik Pavel L. Padnya Alena I. Khadieva Rustem R. Gamirov Yulia V. Panina Asiya F. Gazizova Denis Yu. Grishaev Vitaliy V. Plemenkov Ivan I. Stoikov 《International journal of molecular sciences》2021,22(15)
In recent years, meroterpenoids have found wide biomedical application due to their synthetic availability, low toxicity, and biocompatibility. However, these compounds are not used in targeted drug delivery systems due to their high affinity for cell membranes, both healthy and in cancer cells. Using the approach of creating supramolecular amphiphiles, we have developed self-assembling systems based on water-soluble pillar[5]arene and synthetic meroterpenoids containing geraniol, myrtenol, farnesol, and phytol fragments. The resulting systems can be used as universal drug delivery systems. It was shown by turbidimetry that the obtained pillar[5]arene/synthetic meroterpenoid systems do not interact with the model cell membrane at pH = 7.4, but the associates are destroyed at pH = 4.1. In this case, the synthetic meroterpenoid is incorporated into the lipid bilayer of the model membrane. The characteristics of supramolecular self-assembly, association constants and stoichiometry of the most stable pillar[5]arene/synthetic meroterpenoid complexes were established by UV-vis spectroscopy and dynamic light scattering (DLS). It was shown that supramolecular amphiphiles based on pillar[5]arene/synthetic meroterpenoid systems form monodisperse associates in a wide range of concentrations. The inclusion of the antitumor drug 5-fluoro-2′-deoxyuridine (floxuridine) into the structure of the supramolecular associate was demonstrated by DLS, 19F, 2D DOSY NMR spectroscopy. 相似文献
95.
AB Jamjoom NF Khalaf AA Mohammed ZA Jamjoom TY Kashoggi OB Abdelbasit NU Rahman 《Canadian Metallurgical Quarterly》1998,140(11):1121-1125
In this study, the authors attempt to provide an account of the factors that affect the outcome of hydrocephaly in 26 foetuses. The hydrocephalus was related to a myelomeningocele in 35% of patients. Sixty-two percent of foetuses showed intra-uterine progression of their hydrocephalus and 50% were shunted postnatally. At a mean follow up of 2 years, the outcome was considered "fair" in 54% of patients. Our findings demonstrate that in foetal hydrocephaly a more favourable outcome is expected in patients with hydrocephalus which does not progress in utero, in whom the labour is not induced before 36 weeks of gestation, who are delivered vaginally weighing more than 2.5 kg and have a head circumference below the 95th centile and a CT cortical mantle thickness of 2 cm and more and who are treated by CSF shunting. The diagnosis of the foetal hydrocephaly at or before 28 weeks of gestation and the presence of a myelomeningocele did not affect the outcome significantly. Neurosurgeons are reminded to keep an open mind for infants with foetal hydrocephaly and to offer active treatment to patients with a potentially favourable outcome. 相似文献
96.
97.
S. E. Mamedov E. I. Akhmedov S. S. Dadasheva N. F. Akhmedova 《Petroleum Chemistry》2016,56(7):587-590
The catalytic properties of zinc-modified, Ultrasil type high-silica zeolite in thermal catalytic conversion of gas condensate to produce olefins and aromatic hydrocarbons have been studied. Methods for controlling the product composition by varying zinc concentration and by steaming the modified zeolite have been proposed. It has been shown that the treatment of Zn–H-Ultrasil leads to the formation of Brønsted type weakly acidic OH group having an absorption band at 3670 cm–1, which reduces the contribution of hydrogen redistribution reactions and enhances selectivity for lower C2–C4 olefins. 相似文献
98.
V. I. Vasil’ev D. Akhmedov A. G. Geryagin V. I. Kuchinskii I. P. Nikitina V. M. Smirnov D. N. Tret’yakov 《Semiconductors》1999,33(9):1034-1036
Nearly isoperiodic solitary Ga1−x
InxAsySb1−y
/GaSb heterostructures, in which the composition of the solid solution should be found inside the region of spinodal decay
(x⩽0.4), were grown by liquid-phase epitaxy from solution-melts enriched with antimony. On the basis of the results of a study
of structural and luminescence properties of Ga1−x
InxAsySb1−y
/GaSb heterostructures we have determined the main conditions ensuring reproducible growth of epitaxial layers, homogeneous
in the composition of their solid solutions in the region where the existence of processes of spinodal and binodal decay have
been theoretically predicted. It is shown that the magnitude and sign of the deformation which the layer undergoes during
growth and also the thickness of the layer are the main factors influencing the properties of the growing GaInAsSb solid solutions
in the spinodal-decay zone.
Fiz. Tekh. Poluprovodn. 33, 1134–1136 (September 1999) 相似文献
99.
JK Barnett D Barnett CA Bolin TA Summers EA Wagar NF Cheville RA Hartskeerl DA Haake 《Canadian Metallurgical Quarterly》1999,67(2):853-861
The outer membrane of pathogenic Leptospira species grown in culture media contains lipopolysaccharide (LPS), a porin (OmpL1), and several lipoproteins, including LipL36 and LipL41. The purpose of this study was to characterize the expression and distribution of these outer membrane antigens during renal infection. Hamsters were challenged with host-derived Leptospira kirschneri to generate sera which contained antibodies to antigens expressed in vivo. Immunoblotting performed with sera from animals challenged with these host-derived organisms demonstrated reactivity with OmpL1, LipL41, and several other proteins but not with LipL36. Although LipL36 is a prominent outer membrane antigen of cultivated L. kirschneri, its expression also could not be detected in infected hamster kidney tissue by immunohistochemistry, indicating that expression of this protein is down-regulated in vivo. In contrast, LPS, OmpL1, and LipL41 were demonstrated on organisms colonizing the lumen of proximal convoluted renal tubules at both 10 and 28 days postinfection. Tubular epithelial cells around the luminal colonies had fine granular cytoplasmic LPS. When the cellular inflammatory response was present in the renal interstitium at 28 days postinfection, LPS and OmpL1 were also detectable within interstitial phagocytes. These data establish that outer membrane components expressed during infection have roles in the induction and persistence of leptospiral interstitial nephritis. 相似文献
100.