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1.
Jovita Pudlauskaitė Virginija Jankauskaitė Algirdas Lazauskas Igoris Prosyčevas Pranas Narmontas 《Colloid and polymer science》2013,291(8):1787-1793
In this study, the detailed characterisation of silver (Ag) nanoparticles/polymer nanocomposite chemical structure and morphology of grating has been carried out. Scanning electron microscopy measurements show spherical shape of Ag nanoparticles (40–80 nm in diameter) prepared in chloroform by reduction of silver nitrate. In the positive photoresist based on 2-diazo-2H-naphthalen-1-one (DNQ)–novolac, Ag nanoparticles were deposited from organic colloidal solution. The content of nanoparticles in the polymer matrix was varied by increasing the concentration of Ag colloidal solution. Grating was formed by contact lithography. The quantification of Ag nanoparticles and chemical analysis of Ag/DNQ-novolac-based nanocomposite was performed by means of energy dispersive X-ray analyzer and SEM/EDS. In order to study the effect of Ag nanoparticles on the DNQ-novolac-based nanocomposite structure, investigations with Fourier transform infrared spectroscopy were conducted. Ag nanoparticles cause changes associated with substituent-sensitive out-of-plane C–H bending vibrations of aromatic ring. Ag/DNQ-novolac-based nanocomposite film surface morphology and grating topography imaging were performed using atomic force microscopy. Added Ag nanoparticles change the geometrical parameters of the gratings. The split of corrugations was achieved in Ag/DNQ-novolac-patterned films. Their morphology can be tailored by altering the content of Ag nanoparticles. 相似文献
2.
Romualdas Smicius Virginija Jakubkiene Milda M. Burbuliene Povilas Vainilavicius 《Monatshefte für Chemie / Chemical Monthly》2002,7(1):173-181
Treatment of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with haloalkanes yielded oxadiazole S-alkyl derivatives, whereas its reaction with formaldehyde and amines resulted in formation of oxadiazole N(3)-aminomethyl derivatives. The alkylation of 2-alkylsulfanyl-5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles with methyl bromoacetate proceeded at the N(1)-position of pyrimidine to give 2-alkylsulfanyl-5-(1-methoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles, whereas aminomethylation, bromination, or nitration took place at position 5 of pyrimidine ring and afforded the corresponding 5-pyrimidine substituted derivatives. 相似文献
3.
Films of a binary polymer blends comprising polychloroprene (PCP) and piperylene-styrene copolymer (PSC) have been prepared by solution casting. The dependence of the surface morphology of the free blend films on PSC content was studied with both roughness and correlation analysis of lateral force microscopy (LFM) images. Significant changes in roughness and lateral parameter values of different blend film sides have been observed depending on the blend composition. It was shown that up to 15 wt.% PSC is distributed continuously in PCP bulk. The increase of roughness and lateral parameter values at the air/film surface shows the enrichment of PCP in the blends containing 25 wt.% or more PSC. The enrichment of PCP on the air/film surface favours the increase of PSC concentration at the backing/film surface. The films underside morphology becomes similar to that of PSC, when its content reaches 40 wt.%. 相似文献
4.
Romualdas Smičius Milda Malvina Burbuliene Virginija Jakubkienė Emilija Udrwėnaitė Povilas Vainilavičius 《Journal of heterocyclic chemistry》2007,44(2):279-284
Various 4‐amino‐2,3‐dihydro‐4H‐triazoles with aromatic, aliphatic and heterocyclic substituents at the C(5) position were synthesized from corresponding esters and thiocarbohydrazide. This method allows the synthesis these heterocycles in a short time and at reduced expenses. 相似文献
5.
Povilas Vainilavicius Romualdas Smicius Virginija Jakubkiene Sigitas Tumkevicius 《Monatshefte für Chemie / Chemical Monthly》2001,132(7):825-831
Summary. In the reaction of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with hydrazine
hydrate, 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-amino-1,2,4-triazole-3-thione was formed. The reactions
of the latter with ethyl bromoacetate and chloroacetonitrile in the presence of triethylamine proceeded under formation of
the corresponding S-alkylated derivatives, whereas from its reaction with ω-bromoacetophenone and ethyl 4-chloroacetoacetate
triazolothiadiazines were obtained. Treatment of the title compound with ethyl 2-chloroacetoacetate led to the formation of
5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-N-acetylamino-(3-ethoxy-carbonylmethylthio)-1,2,4-triazole.
Performing of the latter reaction without basic catalyst gave a triazolothiadiazine. Treatment of the S-alkylated derivatives
with sodium methoxide resulted in triazolothiadiazines via a cyclocondensation reaction.
Received November 20, 2000. Accepted January 15, 2001 相似文献
6.
The report about a series of unexpected and obscure effects influencing the electrophilic nitrosation of activated pyrimidines (Tetrahedron 2007, 63, 5394) was shown to be erroneous. Instead of electrophilic substitution at position 5 of the pyrimidine ring, N-nitrosation of the secondary amino group in the 4-position of the pyrimidine ring took place. Moreover it was shown that the synthetic sequence for the preparation of purines is also incorrect. 相似文献
7.
Mangirdas Malinauskas Daiva Baltriukiene Antanas Kraniauskas Paulius Danilevicius Rasa Jarasiene Raimondas Sirmenis Albertas Zukauskas Evaldas Balciunas Vytautas Purlys Roaldas Gadonas Virginija Bukelskiene Vytautas Sirvydis Algis Piskarskas 《Applied Physics A: Materials Science & Processing》2012,108(3):751-759
Films and microstructured scaffolds have been fabricated using direct laser writing out of different polymers: hybrid organic-inorganic ORMOCORE b59, acrylate-based AKRE23, novel organic-inorganic Zr containing hybrid SZ2080, and biodegradable PEG-DA-258. Adult myogenic stem cells were grown on these surfaces in vitro. Their adhesion, growth, and viability test results suggest good potential applicability of the materials in biomedical practice. Pieces of these polymers were implanted in rat’s paravertebral back tissue. Histological examination of the implants and surrounding tissue ex vivo after 3 weeks of implantation was conducted and results show the materials to be at least as biocompatible as surgical clips or sutures. The applied direct laser writing technique seems to offer good future prospects in a polymeric 3D scaffold design for artificial tissue engineering with autologous stem cells. 相似文献
8.
Virginija Jakubkiene Zana Kacnova Milda M. Burbuliene Povilas Vainilavicius 《Journal of heterocyclic chemistry》2008,45(5):1391-1395
[2‐Alkylthio‐6‐methyl‐4‐oxopyrimidin‐3(4H)‐yl]acetonitriles ( 3‐5 ) treated with sodium methoxide in methanol followed by ammonium chloride were cyclized to 2‐imino‐7‐methyl‐2,3‐dihydroimidazo[1,2‐a]‐pyrimidin‐5(1H)‐ones ( 6‐8 ). Under acid or base‐catalyzed hydrolysis they were converted to 7‐methyl‐imidazo[1,2‐a]pyrimidine‐2,5‐[1H,3H]‐diones ( 9‐11 ), whereas in the reaction with butyl‐ or benzylamine the corresponding 7‐methyl‐2‐(substitutedamino)imidazo[1,2‐a]pyrimidin‐5(3H)‐ones ( 13‐18 ) were produced. The latter were found to exist in two tautomeric forms in CDCl3 solution. 相似文献
9.
Romualdas Smicius Virginija Jakubkiene Milda M. Burbuliene Povilas Vainilavicius 《Monatshefte für Chemie / Chemical Monthly》2002,133(2):173-181
Summary. Treatment of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with haloalkanes yielded
oxadiazole S-alkyl derivatives, whereas its reaction with formaldehyde and amines resulted in formation of oxadiazole N(3)-aminomethyl
derivatives. The alkylation of 2-alkylsulfanyl-5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles
with methyl bromoacetate proceeded at the N(1)-position of pyrimidine to give 2-alkylsulfanyl-5-(1-methoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles,
whereas aminomethylation, bromination, or nitration took place at position 5 of pyrimidine ring and afforded the corresponding
5-pyrimidine substituted derivatives.
Received May 9, 2001. Accepted (revised) August 17, 2001 相似文献
10.
Povilas?Mie?inskas Konstantinas?Leinartas Virginija?Uksien? Eimutis?JuzeliūnasEmail author 《Journal of Solid State Electrochemistry》2007,11(7):909-913
The study demonstrated a possibility to sense the activity of microorganisms on metals in situ under atmosphere conditions
using a quartz crystal microbalance (QCM) as a sensitive mass change detector. Other innovative aspects of the QCM application
include long-term monitoring (over month), taking count of the influence of atmospheric pressure and application of Al-glued
foil electrodes. The research subject was aluminium colonisation by Aspergillus niger Tiegh., a filamentous ascomycete fungus. The difference between the QCM data for abiotic and biotic samples reflected microbiological
activity, which resulted in exponential mass gain during exposure. The increase in mass was due to various phenomena, i.e.
development of biomass, secretion of metabolites, water uptake by the colony and microbially induced corrosion. The glued
foil method demonstrated a possibility to expand the scope of the QCM studies from evaporated, sputtered or electroplated
materials to those, from which thin foils may be produced.
Dedicated to Professor Dr. Algirdas Vaškelis on the occasion of his 70th birthday. 相似文献