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    Wyświetlanie 1-10 z 10
    Tytuł:
    Demonstration of Wet Chemical Synthesis of Nanomaterials for High School Students
    Autorzy:
    Acharyya, Swarnali
    Acharyya, Sarani
    Samanta, Pijus Kanti
    Powiązania:
    https://bibliotekanauki.pl/articles/1031206.pdf
    Data publikacji:
    2020
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Chemical Synthesis
    Electronics
    Nanomaterials
    Nanotechnology
    School-education
    Opis:
    Nanotechnology is the most emerging branch of science and technology leading to the development of devices starting from electronics to biomedical devices. It is thus desired that the students should have basic idea of this new emerging technology during their school education. Experimental demonstration of simple experiments of synthesizing nanomaterials and demonstration of its properties are very much important in motivating the students to learn this new technology. Wet chemical synthesis method is a simple and cost-effective method that can be adopted in the chemistry laboratory of higher secondary level school education in India. This hands-on experience will encourage the students to enter more into this nanotechnology.
    Źródło:
    World Scientific News; 2020, 148; 15-26
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    THE INFLUENCE OF POLYETHER SUBSTITUENTS ON BIOLOGICAL ACTIVITY OF CURCUMIN DERIVATIVES
    Autorzy:
    Gruber, Beata M.
    Tomasz, Deptuła
    Adam, Krówczyński
    Irena, Bubko
    Powiązania:
    https://bibliotekanauki.pl/articles/895397.pdf
    Data publikacji:
    2020-02-29
    Wydawca:
    Polskie Towarzystwo Farmaceutyczne
    Tematy:
    Chemical synthesis
    cytotoxic activity
    curcumin derivatives
    antitumor drugs
    Opis:
    Curcumin is reported as an anti proliferative and chemopreventive compound. However, it shows poor water solubility, low bioavailability, and rapid metabolism.. To address these problems, curcumin derivatives substituted with polyether chain were synthesised to improve the hydrophilicity of curcumin and thus its bioavailability. The biological activity of modified curcumin molecules were studied with human normal B-lymphocytes GM 14667 and human leukemia cells HL60 and covered: the denotation of IC50 values for each new compound with use of MTT test and the studies on apoptosis induction observed as morphological changes and the expression of apoptotic proteins, BAX, BCL-2 and survivin with use of Western Blot analysis. All effects were referenced to native curcumin. The derivatives with modified polyether chains number and the position of methoxy- groups were selected for further studies. As was shown, the solubility of the compound does not directly correlate with its cytotoxicity. The maintenance of the methoxy group in the meta position as well as the introduction of hydrophilic polyether chains but not the number of polyether chains may affect the cytotoxic activity of curcumin derivatives against cancer cells. Modifications of the curcumin molecule structure can determine its impact on the profile of pro or anti apoptotic proteins.
    Źródło:
    Acta Poloniae Pharmaceutica - Drug Research; 2020, 77, 1; 99-111
    0001-6837
    2353-5288
    Pojawia się w:
    Acta Poloniae Pharmaceutica - Drug Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and structural characterization of niobium-doped hydroxyapatite ceramics
    Autorzy:
    Korzeniewski, Wojciech
    Witkowska, Agnieszka
    Powiązania:
    https://bibliotekanauki.pl/articles/284989.pdf
    Data publikacji:
    2019
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
    Tematy:
    structure
    nanoceramics
    sol-gel method
    hydroxyapatite
    niobium
    mechano-chemical synthesis
    Opis:
    Hydroxyapatite (HAp) ceramic materials are consi-dered as one of the most promising implant materials in bone surgery and in dentistry. They exhibit unique biocompatibility, bioactivity, and osteoconductivity, which are the most desirable biomaterial features. However, HAp itself is brittle, has low strength, high degree of crystallinity and low solubility at physiological pH. Doping synthetic HAp with metal ions plays an important role in improving its structural and physico--chemical properties. HAp doped with niobium ions has not been widely investigated so far. However, the results of studies available in the literature show that the synthesized CaO-P2O5-Nb2O5 compounds still show good biocompatibility, very low cytotoxicity and, additionally, they stimulate osteoblast proliferation. Therefore, this study is dedicated to the niobium--doped HAp ceramics obtained by two methods: mechano-chemical synthesis and sol-gel method. Bioceramics chemical composition, morphology, and structure were characterized by means of scanning electron microscopy imaging, BET method, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results indicate that nanoceramics of non-stoichiometric HAp with a clear Ca deficiency on the nanograin surface were obtained. Moreover, it has been observed that the presence of Nb dopants and the synthesis method directly affect unit cell parameters, crystallinity degree, crystallites size, porosity and distribution of niobium in the grain structure. Mechano-chemical synthesis has allowed effective niobium incorporation into the HAp structure, leading to the quite homogeneous Nb distribution in the grain volume. Whereas, Nb-doping by sol-gel method has led to dopants location mainly on the grain surface.
    Źródło:
    Engineering of Biomaterials; 2019, 22, 150; 10-15
    1429-7248
    Pojawia się w:
    Engineering of Biomaterials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Immunosuppressory activity of the cyclodimeric peptide with RGD-sequences.
    Autorzy:
    Szewczuk, Zbigniew
    Buczek, Paweł
    Stefanowicz, Piotr
    Krajewski, Krzysztof
    Wieczorek, Zbigniew
    Siemion, Ignacy
    Powiązania:
    https://bibliotekanauki.pl/articles/1044172.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    dimeric analog
    chemical synthesis
    homodetic cyclization
    histocompatibility antigen
    HLA-DQ
    RGD-sequence
    MHC class-II
    Opis:
    Our previous studies showed that the nonapeptide fragment of HLA-DQ of the sequence H-Thr-Pro-Gln-Arg-Gly-Asp-Val-Tyr-Thr-OH, located in the β164-172 loop, strongly suppresses the humoral and cellular immune responses, while its shorter analogs, H-Arg-Gly-Asp-Val-OH, H-Arg-Gly-Asp-Val-Tyr-OH and H-Gln-Arg-Gly-Asp-Val-Tyr-OH show only a weak stimulatory activity in respect to the humoral immunological response. These fragments contain the Arg-Gly-Asp (RGD) sequence, known for its importance for cellular association phenomena. Based on the crystal structure of HLA-DR1, we also designed and synthesized a cyclic analog H-Cys-Arg-Gly-Asp-Val-Tyr-Cys-OH with restricted conformation, which strongly suppresses the immune response and selectively inhibits the αvβ3 integrin, suggesting that the mechanism of the immunosuppressory action of the peptide is associated with inhibition of the integrin. In this paper we present the design and synthesis of the cyclodimeric peptide, Arg-Gly-Asp-Arg-Gly-Asp, which is also known as a selective αvβ3 inhibitor. The synthesized peptide strongly suppresses both the humoral and cellular immune response. The results support our hypothesis that the immunomodulatory activity of HLA-DQ fragments may be connected with their interactions with some particular integrins on the cell surface.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 1; 121-130
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design, synthesis and biological evaluation of a new bridged immunosuppressor.
    Autorzy:
    Szewczuk, Zbigniew
    Wilczyński, Andrzej
    Petry, Inga
    Siemion, Ignacy
    Wieczorek, Zbigniew
    Powiązania:
    https://bibliotekanauki.pl/articles/1044065.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    chemical synthesis
    MS-MS sequencing
    histocompatibility antigen
    bridged analog
    HLA-DQ
    RGD-sequence
    MHC class-II
    Opis:
    A bridged peptide with the sequence: H-Thr-Pro-Gln-Arg-Gly-Asp-Val-γ-Abu-Asn-Asp-Gln-Glu-Glu-Thr-Thr-Gly-Val-Val-Ser-Thr-Pro-Leu-Ile-Arg-Asn-Gly-OH was designed to mimic the discontinuous epitope of the HLA-DQ molecule that might interact with CD4. The bridged peptide revealed distinct suppressory effect in the humoral immune response. This result supports our suggestion that the 164-172 region of the HLA-DQ molecule may enhance its interactions with coreceptors, possibly with CD4.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 4; 1147-1150
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kinetics of nanocrystalline iron nitriding
    Autorzy:
    Arabczyk, W.
    Zamłynny, J.
    Moszyński, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/778372.pdf
    Data publikacji:
    2010
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    azotki żelaza
    materiały mikroporowate
    synteza chemiczna
    analiza termograwimetryczna
    dyfrakcja promieniowania rentgenowskiego
    iron nitrides
    microporous materials
    chemical synthesis
    thermogravimetric analysis
    X-ray diffraction
    Opis:
    Nitriding of nanocrystalline iron was studied under the atmosphere of pure ammonia and in the mixtures of ammonia - hydrogen - nitrogen at temperatures between 350°C and 500°C using thermogravimetry and x-ray diffraction. Three stages of nitriding were observed and have been ascribed to the following schematic reactions: (1) α-Fe → γ-Fe4N, (2) γ- Fe4N → ε - Fe3N and (3) ε - Fe3N → ε - Fe2N. The products of these reactions appeared in the nitrided nanocrystalline iron not sequentially but co-existed at certain reaction ranges. The dependence of a reaction rate for each nitriding stage on partial pressure of ammonia is linear. Moreover, a minimal ammonia partial pressure is required to initiate the nitriding at each stage.
    Źródło:
    Polish Journal of Chemical Technology; 2010, 12, 1; 38-43
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Justification of the most rational method for the nanostructures synthesis on the semiconductors surface
    Autorzy:
    Suchikova, Y.
    Vambol, S.
    Vambol, V.
    Mozaffari, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/368501.pdf
    Data publikacji:
    2019
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    hierarchies’ analysis method
    chemical etching
    electrochemical etching
    lithographic etching
    nanostructures synthesis
    metoda hierarchii analitycznej
    trawienie chemiczne
    wytrawianie elektrochemiczne
    litografia
    synteza nanostruktur
    Opis:
    Purpose: of this paper is to justification the most rational method for the nanostructures synthesis on the semiconductors surface, which is capable of providing high quality synthesized nanostructures at low cost and ease of the process. Design/methodology/approach: The choice of the optimal method of synthesis was carried out using the hierarchy analysis method, which is implemented by decomposing the problem into more simple parts and further processing judgments at each hierarchical level using pair comparisons. Findings: The article describes the main methods of synthesis of nanostructures, presents their advantages and disadvantages. The methods were evaluated by such criteria as: environmental friendliness, efficiency, stages number of the technological process, complexity, resources expenditure and time and effectiveness. Using the hierarchy analysis method, has been established that electrochemical etching is the most important alternative, and when choosing a nanostructures synthesis method on the semiconductors surface, this method should be preferred. Such studies are necessary for industrial serial production of nanostructures and allow reducing expenses at the realization of the problem of synthesis of qualitative samples. Research limitations/implications: In this research, the hierarchy analysis method was used only to select a rational method for synthesizing nanostructures on the semiconductors surface. However, this research needs to be developed with respect to establishing a correlation between the synthesis conditions and the nanostructures acquired properties. Practical implications: First, was been established that the optimal method for the nanostructures synthesis on the semiconductors surface is electrochemical etching, and not lithographic or chemical method. This allowed the theoretical and empirical point of view to justify the choice of the nanostructures synthesis method in the industrial production conditions. Secondly, the presented method can be applied to the synthesis method choice of other nanostructures types, which is necessary in conditions of resources exhaustion and high raw materials cost. Originality/value: In the article, for the first time, the choice of the nanostructures synthesis method on the semiconductors surface is presented using of paired comparisons of criteria and available alternatives. The article will be useful to engineers involved in the nanostructures synthesis, researchers and scientists, as well as students studying in the field of "nanotechnology".
    Źródło:
    Journal of Achievements in Materials and Manufacturing Engineering; 2019, 92, 1-2; 19-28
    1734-8412
    Pojawia się w:
    Journal of Achievements in Materials and Manufacturing Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Batch control of microwave hydrothermal synthesis of nanopowders process
    Wsadowa realizacja procesów hydrotermalnej syntezy nanoproszków
    Autorzy:
    Majcher, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/257610.pdf
    Data publikacji:
    2015
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Technologii Eksploatacji - Państwowy Instytut Badawczy
    Tematy:
    batch control of chemical processes
    microwave-hydrothermal synthesis
    stop-flow mode
    nanopowders
    sterowanie wsadowe
    mikrofalowa synteza hydrotermalna
    tryb pracy stop-flow
    nanoproszki
    Opis:
    Microwave hydrothermal synthesis processes allow to obtain the nanopowders of extremely high quality. However, their disadvantage in terms of industrial applications is low productivity. The article presents a technological system that breaks this barrier. A novel chemical reactor is described. The reactor has a unique design of process chamber, which used in conjunction with a batch control system allows highly efficient production of nanopowders to be obtained. The design of the reactor together with new principles of operation, structural materials, and distribution of electromagnetic field are described. The paper also presents a control system for the reactor, which allows for automatic operation in the stop-flow mode, control of process pressure, continuous monitoring of process parameters and safe operation of the device.
    Mikrofalowe hydrotermalne procesy syntezy pozwalają na uzyskiwanie nanoproszków o wyjątkowo wysokiej jakości. Natomiast ich wadą w aspekcie zastosowań przemysłowych jest niska wydajność. W artykule przedstawiono system technologiczny, który przełamuje tę barierę. Opracowano nowy typ reaktora, posiadającego unikatową konstrukcję komory procesowej, co w połączeniu z zastosowanym systemem sterowania wsadowego pozwala na uzyskiwanie dużej wydajności produkcji nanoproszków. Opisano konstrukcję reaktora z uwzględnieniem nowej zasady działania, materiałów konstrukcyjnych, rozkładu pola elektromagnetycznego. Przedstawiono system sterowania urządzeniem, który zapewnia automatyczną realizację procesów, regulację ciśnienia procesu, ciągłe monitorowanie parametrów procesów oraz zachowanie bezpieczeństwa obsługi urządzenia.
    Źródło:
    Problemy Eksploatacji; 2015, 3; 5-16
    1232-9312
    Pojawia się w:
    Problemy Eksploatacji
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Automation of the process of microwave hydrothermal synthesis of nanopowders
    Automatyzacja procesu mikrofalowej hydrotermalnej syntezy nanoproszków
    Autorzy:
    Majcher, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/276565.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
    Tematy:
    automatyzacja procesów chemicznych
    mikrofalowa synteza hydrotermalna
    stop-flow
    sterowanie wsadowe
    nanoproszki
    automation of chemical processes
    microwave-hydrothermal synthesis
    stop-flow mode
    batch control
    nanopowders
    Opis:
    The article presents the process of microwave hydrothermal synthesis of nanopowders automation. The essential elements of automation are: a novel reactor and its control system. The reactor has a unique design of process chamber, which used in conjunction with a batch control system allows highly efficient production of nanopowders to be obtained. The design of the reactor together with new principles of operation, structural materials, and distribution of electromagnetic field are described. The paper also presents a control system for the reactor, which allows for automatic operation in the stop-flow mode, control of process pressure, continuous monitoring of process parameters and safe operation of the device.
    W artykule przedstawiono automatyzację procesu mikrofalowej hydrotermalnej syntezy nanoproszków. Jej zasadniczymi elementami są: nowy typ reaktora oraz jego system sterowania. Reaktor posiada unikatową konstrukcję komory procesowej, co w połączeniu z zastosowanym systemem sterowania wsadowego pozwala na uzyskiwanie dużej wydajności produkcji nanoproszków. Opisano konstrukcję reaktora z uwzględnieniem nowej zasady działania, materiałów konstrukcyjnych, rozkładu pola elektromagnetycznego. Przedstawiono system sterowania urządzeniem, który zapewnia automatyczną realizacje procesów w trybie stop-flow, regulacje ciśnienia procesu, ciągłe monitorowanie parametrów procesów oraz zachowanie bezpieczeństwa obsługi urządzenia.
    Źródło:
    Pomiary Automatyka Robotyka; 2013, 17, 2; 208-212
    1427-9126
    Pojawia się w:
    Pomiary Automatyka Robotyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects Of Process Parameters On Cu Powder Synthesis Yield And Particle Size In A Wet-Chemical Process
    Wpływ parametrów procesu na wydajność syntezy proszku Cu i wielkości cząstek w procesie mokrym chemicznym
    Autorzy:
    Shin, Y. M.
    Lee, J. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/354168.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    wet-chemical process
    micron-size Cu powder
    Synthesis yield
    particle size
    gibbs free energy difference
    proszek Cu
    proces chemiczny mokry
    wydajność syntezy
    rozmiar cząsteczki
    różnica energii swobodnej Gibbsa
    Opis:
    This study presents a simple wet-chemical process to prepare several micron-size Cu powders. Moreover, changes in powder synthesis yield and particle size are examined with different solvents, synthesis temperatures, and amounts of reducing agent during the synthesis. As a reducing agent and capping agent, L-ascorbic acid and polyvinyl pyrrolidone were used, respectively. The yields in distilled water or an ethylene glycol (EG)/distilled water mixture were higher than that in EG alone, and the yield increased with increasing temperature owing to a lower Δ Gred value. Increasing the L-ascorbic acid concentration also increased the yield. The Cu powder synthesized in 3 h at 90°C in distilled water with 272.8 mM of L-ascorbic acid showed the lowest average particle size of 2.52 μm, indicating mechanisms of short burst nucleation and reduced growth via the increased reduction rate of Cu ions. It is estimated that the nucleation step was nearly completed within 10 min in this system. The Cu powders synthesized in an ethylene glycol/distilled water mixture presented an average particle size of 3.76 μm and the highest yield of 87.9%.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1247-1250
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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