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1

Novel organic material with potential NLO application - electronic and spectroscopic properties

100%

Koleva B. B., Kolev T., Nikolova R., Zagraniarsky Y., Spiteller M.

Open Chemistry

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2008

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vol. 6

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issue 4

592-599

EN

Novel dicyanoisophorone derivative, (E)-2-(3-(4-aminostyryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile, is synthesized and its structure elucidated by means of conventional and linear polarized IR-spectroscopy of oriented colloids in nematic host, 1H, 13C, 1H, 1H-COSY NMR, HPLC tandem ESI MS-MS spectrometry, UV-VIS and thermal methods. Ab initio and DFT level of theory are used to theoretically obtain the electronic structure and optical properties, both in ground and exited state, of the compound. [...]

2

A review on the synthesis of TiO2 nanoparticles by solution route

100%

Gupta S., Tripathi M.

Open Chemistry

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2012

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vol. 10

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issue 2

279-294

EN

TiO2 can be prepared in the form of powder, crystals, or thin films. Liquid-phase processing is one of the most convenient and utilized methods of synthesis. It has the advantage of allowing control over the stoichiometry, production of homogeneous materials, formation of complex shapes, and preparation of composite materials. However, there may be some disadvantages such as expensive precursors, long processing times, and the presence of carbon as an impurity. In comparison, the physical production techniques, although environment friendly, are limited by the size of the produced samples which is not sufficient for a large-scale production. The most commonly used solution routes in the synthesis of TiO2 are reviewed.

3

Synthesis of hydroxyapatite by using calcium carbonate and phosphoric acid in various water-ethanol solvent systems

100%

Engin A., Girgin İ.

Open Chemistry

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2009

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vol. 7

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issue 4

745-751

EN

The purpose of the present study is to synthesize hydroxyapatite by using CaCO3 and H3PO4 in various water-ethanol solvent systems. It was observed from experiments that formation of ammonium phosphate compounds hindered the formation of calcium phosphates in ethanol medium. Although the reactivity was better in aqueous medium, the carbonate contents of the products obtained were above 8.5%. Best results with a carbonate content as low as 3.82% was obtained in 50% ethanol containing mixed-aqueous medium at 80°C and the FTIR analysis showed that the product was a carbonated apatite with a calculated composition of 14CaO·4.2P2O5·CO3·7.2H2O. The amorphous and porous phosphate compound obtained with a BET surface area of 106.6 m2 g−1 seems to be useful as adsorbent in wastewater treatment. Upon sintering of the amorphous product at 750°C, crystalline hydroxyapatite with a BET surface area of 25.9 m2 g−1 is obtained that may be used in biomedical applications. [...]

4

Synthesis and characterization of thermoresponsive hydrogels cross-linked with chitosan

100%

Yu Y., Chang X., Ning H., Zhang S.

Open Chemistry

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2008

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vol. 6

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issue 1

107-113

EN

Hydrogels composed of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) were prepared by redox polymerization with degradable chitosan cross-linkers. Chitosan degradable cross-linkers were synthesized by the acrylation of the amine groups of glucosamine units within chitosan and characterized with 1H NMR. With the chitosan cross-linkers, loosely cross-linked poly(N-isopropylacryamideco-acrylic acid) [P(NIPAAm-co-AAc)] hydrogels were prepared, and their phase transition behavior, lower critical solution temperature (LCST), water content and degradation properties were investigated. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels were pliable and transparent at room temperature. The LCST could be adjusted at 32∼39°C by alternating the feed ratio. Swelling was influenced by NIPAAm/AAc monomer ratio, cross-linking density, swelling media, and temperature. All hydrogels with different feeding ratios contained more than 95% water at 25°C in the ultra pure water and phosphate-buffered saline (PBS, pH = 7.4 ± 0.1), and had a prospective swelling in the simulated gastric fluids (SGF, pH = 1.2) > 72.54%. In degradation studies, breakdown of the chitosan cross-linked P(NIPAAm-co-AAc) hydrogels was dependent on the cross-linking density. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels which can be tailored to create environmentally-responsive artificial extracellular materials have great potential for future use. [...]

5

Paclitaxel as an anticancer agent: isolation, activity, synthesis and stability

88%

Nikolic V., Savic I., Savic I., Nikolic L., Stankovic M., Marinkovic V.

Open Medicine

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2011

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vol. 6

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issue 5

527-536

EN

Paclitaxel is isolated from the Pacific yew. It can be obtained from the European yew, but only after chemical modification of the isolated compound by a semi-synthesis procedure. The procedure for total synthesis of paclitaxel is very complicated, involving multiple steps, and the yields of paclitaxel are meagre. This substance is also a metabolite of certain kinds of fungus. The microbiological pathway for producing paclitaxel compared with isolation from plant material involves shorter procuction times but a small yield. Cyclodextrins are usually used for improving the solubility of paclitaxel in aqueous media, with polymeric and other substances added. Paclitaxel has anticancer activity and use for preparing the formulations intravenously administrated to patients with tumors. The paclitaxel concentration in these formulations is determined using validated HPLC methods.

6

Synthesis and structural characterization of amino-functionalized polysaccharides

88%

Sisu I., Udrescu V., Flangea C., Tudor S., Dinca N., Rusnac L., Zamfir A., Sisu E.

Open Chemistry

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2009

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vol. 7

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issue 1

66-73

EN

A variety of carbohydrates, in particular polysaccharides can be subjected to chemical modification to obtain derivatives with amphiphilic properties, which enable biochemical or biological reactions at the polymer surface. In the present work, a polydisperse maltodextrin mixture of average molecular weight 3000 was coupled with 1,6-hexamethylenediamine (HMD) via reductive amination reaction. Resulting products were characterized by thermal analysis and positive nanoelectrospray quadrupole time-of-flight (Q-TOF) mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Both thermal analysis and MS screening confirmed the formation of the HMD-polysaccharide coupling products. Moreover, HMD-linked polysaccharide chains containing 2 to 26 glucose building blocks were identified by nanoESI Q-TOF MS. MS/MS fragmentation using collision-induced dissociation (CID) at low ion acceleration energies provided strong evidence for HMD-maltodextrin linkage formation and the set of sequence ions diagnostic for the composition and structure of a HMD-linked chain containing 18 glucose residues. [...]

7

In silico screening, synthesis, in vitro evaluations antibacterial and DPPH scavenging activity of some 1,3,5-trisubstituted 2-pyrazoline derivatives as dihydrofolate reductase inhibitors

88%

Suriya S., Mala V.

World News of Natural Sciences

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2018

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vol. 18

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issue 2

180-186

EN

In this work, synthesis of three pyrazoline derivatives (6-8) is described. (E)-1,3-(phenylsubstituted)-prop-2-en-1-one (3-5) is prepared by the reaction of substituted benzaldehyde with 4-methylacetophenone, whereas condensation cyclization of the same chalcones (3-5) with phenylhydrazine hydrate in ethanol yielded 6-8. The structures of the title compounds (6-8) were characterized by chemical reactions, elemental analysis, and spectral methods such as IR spectra. The synthesized chalcone and pyrazolines were evaluated for in-vitro antibacterial and antioxidant activities against standard. The zone of inhibition for some of the newly synthesized compounds showed notable antibacterial activity against selected bacterial strains when compared with ampicillin. Significant antioxidant activities were also shown by chalcone and pyrazolines.

8

Synthesis and monolayer film of a series of new twin-tailed gemini cationic surfactants at the air/water interface

88%

Chen Z., Feng Y., Zhou D., Zhu P., Wu D.

Open Chemistry

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2008

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vol. 6

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issue 3

477-481

EN

A series of new dimeric surfactants, twin-tailed gemini surfactants, 2(12)-s-2(12), were successfully prepared and characterized, and their monolayer films investigated by the measurement of surface pressure-area (π-A) and surface pressure-time (π-t) isotherms at the air/water interface by a Langmuir film balance. Compared to their monomeric counterparts, their collapse pressure (γcollapse) is smaller, whilst all the molecular area parameters are larger. The limited area (Alimited) and the initial area (Ainitial) of these twin-tailed gemini surfactants change with increasing spacer length s, and the surface pressure decreases with increasing time. It was also found that the higher the initial surface pressure, the larger the attenuation. [...]

9

The Poincaré theorem in linear circuit synthesis

88%

Siwczyński M., Jaraczewski M.

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2007

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vol. 55

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issue 1

10

Development of FeOOH nanoarrays using magnetic cations

88%

Garcia-Casillas P., Martinez-Pérez C., González C., Camacho-Montes H., Martel Estrada S., Armendáriz I.

Open Chemistry

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2013

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vol. 11

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issue 3

358-363

EN

Abstract In this work, FeOOH arrays were obtained using two different magnetic cations. The nanoparticles were grouped into a package having different orientations through the van der Waals interaction with the magnetic cations. With Fe2+, the FeOOH nanoparticles have a rod shape with a 30-nm diameter and approximately 1-micron length, and are aligned in a star structure. With Co2+, a somatoidal shape was observed, with 20-nm diameter and 150-nm length and a pathway structure to the array. The chemical synthesis method was used to obtain the nanoarrays. The morphology and the average size of the nanorods and nanowires were determined using Field Emission Scanning Electron Microscopy (FESEM). Fourier Transform Infrared Spectroscopy (FTIR) was used to study the interaction between the nanorods and the cobalt ions. The phases of the material were identified using X-ray Diffraction. Graphical abstract [...]

11

Effects of PVA Polymer Type and Calcination Temperature on Synthesis of Nanocrystalline Yttria Powder by Polymer Solution Route

75%

Yang Y.-K., Lee S.-J.

Archives of Metallurgy and Materials

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2018

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vol. 63

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issue 3

12

Electric circuit analysis by means of optimization criteria Part II – complex circuits

75%

Siwczyński M., Jaraczewski M.

|

2006

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vol. 54

|

issue 1

Refine search results

Novel organic material with potential NLO application - electronic and spectroscopic properties

A review on the synthesis of TiO2 nanoparticles by solution route

Synthesis of hydroxyapatite by using calcium carbonate and phosphoric acid in various water-ethanol solvent systems

Synthesis and characterization of thermoresponsive hydrogels cross-linked with chitosan

Paclitaxel as an anticancer agent: isolation, activity, synthesis and stability

Synthesis and structural characterization of amino-functionalized polysaccharides

In silico screening, synthesis, in vitro evaluations antibacterial and DPPH scavenging activity of some 1,3,5-trisubstituted 2-pyrazoline derivatives as dihydrofolate reductase inhibitors

Synthesis and monolayer film of a series of new twin-tailed gemini cationic surfactants at the air/water interface

The Poincaré theorem in linear circuit synthesis

Development of FeOOH nanoarrays using magnetic cations

Effects of PVA Polymer Type and Calcination Temperature on Synthesis of Nanocrystalline Yttria Powder by Polymer Solution Route

Electric circuit analysis by means of optimization criteria Part II – complex circuits