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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:
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:
Metody syntezy i właściwości fizykochemiczne 2,4,6,8,10,12-heksanitro-2,4,6,8,10,12-heksaazaizowurcytanu (HNIW)
The methods of synthesis and physicochemical properties of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW)
Autorzy:
Borkowski, J.
Czerwińska, M.
Powiązania:
https://bibliotekanauki.pl/articles/171958.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
Cl-20
HNIW
synteza
właściwości chemiczne
właściwości wybuchowe
CL-20
synthesis
chemical properties
explosive properties
Opis:
Explosives have a very rich history of its creation. This history dates back to the ninth century, when the Chinese invented a black powder. In the end of the twentieth century, the first nitroamine polycyclic cage structure was obtained. The representative of this group is 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaizowurtzitane (HNIW, Cl-20). HNIW has recently been the subject of an interest as one of the strongest explosive material. As nitroamine, HNIW is compared to the other energetic materials: RDX i HMX [1, 2]. Researchers [5, 6] showed, that it is possible to replace a variety of typical explosives by HNIW and thanks to that obtain compositions with higher densities, heat of explosion and higher velocity of detonation. In the published papers [7-13, 16] there were presented six polymorphs of HNIW: αβγδε with specific stabilities and structural characteristics. Unfortunately, there is no a direct method of obtaining HNIW. There are at least four steps needed to obtain HNIW. The first step is the synthesis of HBIW [20-22]. The next one is debenzylation reaction of HBIW [20-29] in order to remove the benzyl groups. The third step is removal of the two other benzyl groups and replace them by nitroso, formyl or acetyl groups [20, 24, 30, 32]. In the final step there is a nitration of HNIW precursors [31-37]. The HNIW seems to be a promising explosive and it can replace other currently used energetic materials. However, using HNIW is limited due to the complicated and expensive technology of its production. Therefore, research groups carried out new syntheses of HNIW to eliminated these problem. In this article, review of the literature on the physicochemical properties and synthetic methods for HNIW were presented. The basic physical and explosive parameters of HNIW were summarized. The spatial structure was presented and polymorphs of HNIW were characterized. The methods for obtaining HNIW and intermediate products needed for its preparation were described. The methods of preparation of different HNIW polymorphs were also given.
Źródło:
Wiadomości Chemiczne; 2013, 67, 1-2; 93-109
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
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:
Metody chemicznej ligacji w syntezie peptydów i białek. Część 2
Chemical ligation methods in the synthesis of peptides and proteins. Part 2
Autorzy:
Jędrzejewska, K.
Kropidłowska, M.
Wieczerzak, E.
Powiązania:
https://bibliotekanauki.pl/articles/172242.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
natywna chemiczna ligacja
synteza peptydów
tioester
native chemical ligation
peptide synthesis
thioester
Opis:
Proteins are synthesized only by living organisms. Today, we are able to receive them by recombinant protein expression in bacterial cells. This technique is very useful and gives satisfactory amount of desirable material but it precludes the possibility of introduction of some chemical modifications that are often obligatory. For this reason, chemical synthesis of longer peptide chains is still important and is the object of scientists attention. Over the last century, notion of peptide synthesis took a new meaning. Nowadays, we know a number of innovative methods and also automated devices which help us to make progress in this area. Nevertheless, the synthesis of longer, more complicated peptide chains and proteins still constitutes a problem. Native chemical ligation (NCL) has facilitated the synthesis of numerous complex peptide and protein targets. Expansion of ligation techniques has allowed the entry of peptides into the world of therapeutic drugs [1]. NCL reactions are carried out in aqueous solution and give good yields. Due to mild conditions, NCL overcomes racemic and solubility problems encountered in classical peptide synthesis using protected fragments. The challenge is to synthesize the C-terminal thioester-containing peptide necessary for the transesterification reaction, which is the first step of linking the peptide fragments [2]. In this review we discuss the evolution, advantages and potential applications of chemical ligation reactions. In the first part of this article we described the utility of native chemical ligation approach to non-cysteine containing peptides. This part details a number of important approaches to the synthesis of peptides bearing a C-terminal thioester. Contemporary applications of these techniques to the total chemical synthesis of proteins are also presented.
Źródło:
Wiadomości Chemiczne; 2017, 71, 9-10; 747-761
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
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:
Metody chemicznej ligacji w syntezie peptydów i białek. Część 1
Chemical ligation methods in the synthesis of peptides and proteins. Part 1
Autorzy:
Kropidłowska, M.
Jędrzejewska, K.
Wieczerzak, E.
Powiązania:
https://bibliotekanauki.pl/articles/171570.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
natywna chemiczna ligacja
NCL
kinetycznie kontrolowana ligacja
KCL
synteza peptydów
native chemical ligation
kinetically controlled ligation
peptide synthesis
Opis:
Proteins are biological macromolecules affecting very important functions in the body. They are involved in many biochemical processes. They can perform catalytic functions acting as enzymes. They also participate in the transport of many small molecules and ions – for example one molecule of hemoglobin carries four molecules of oxygen. In addition, proteins serve as antibodies and are involved in transmission of nerve impulses as receptor proteins. Because peptides and proteins perform so important functions, to study them it is essential to obtain these compounds in the greatest possible amounts. The compounds can be obtained generally by three main methods: • by isolation of the native peptides and proteins • by expression in microorganisms • by chemical synthesis. Each of the above methods has its advantages and disadvantages, but only the chemical synthesis gives the possibility to introduce modifications to the structure of the resulting protein, such as the insertion of new functional groups, to give the product in the final form and with satisfactory yield. In this review we present the application of chemical ligation methods in the synthesis of peptides and proteins. We describe in details mechanism of native chemical ligation method and the conditions necessary to carry the reaction [1]. The synthesis of long polypeptide chains by kinetically controlled ligation (KCL) is also depicted [2]. This part of the paper also details a number of approaches to noncysteine containing peptides by chemical ligation methods.
Źródło:
Wiadomości Chemiczne; 2017, 71, 9-10; 727-746
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
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:
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:
Peptydoglikan : budowa, rola biologiczna oraz synteza
Peptidoglycan : structure, biological activity and chemical synthesis
Autorzy:
Samaszko-Fiertek, J.
Dmochowska, B.
Madaj, J.
Powiązania:
https://bibliotekanauki.pl/articles/171802.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
peptydoglikan
synteza chemiczna
biosynteza
aktywność biologiczna
peptidoglycan
chemical synthesis
biosynthesis
biological activity
Opis:
The most important component of bacterial cell walls especially Gram-positive bacteria is peptidoglycan, called also murein, PGN. The first time this synonym was used in 1964 by Weidel and Pelzer [1]. Peptidoglycan is present in the outer layer of the cytoplasmic membrane and its structure. The structure of peptidoglycan depends on the bacteria strain. It is estimated that in Gram-negative bacteria, it occupies only about 10–20% of the total area of the cell wall, when in Gram-positive bacteria it is 50 and up to 90% of all space. Problems with isolation with high purity of biological material shows the need for developing techniques for chemical synthesis of peptidoglycan fragments and their analogs. In past few years there has been a growing interest within the synthesis of compounds glycoprotein (glycopeptides, peptidoglycan, etc.). As a basis for the construction of cell walls of many bacteria. Despite intensive research and gain significant knowledge of the physical and biological, chemical synthesis or biosynthesis (Fig. 5 and 6) of peptidoglycan, not so far failed to unambiguously determine its three-dimensional structure. The works of Kelman and Rogers [15] and Dimitriev [20] nearer picture of its structure. However, the time to develop in vivo visualization of cell structure it will be difficult to identify correctly peptidoglycan three-dimensional structure. Due to the important biological roles of murein, many research centers have taken to attempt their chemical synthesis. For biological research began to use chemically synthesized peptidoglycan fragments which guaranteed both uniform and a certain structure. An important roles in the development of methods of chemical synthesis of peptidoglycan had H. Chowdhury work, Fig. 8 [35], Hesek, Fig. 9 and 10 [36, 37], Dziarskiego [38] and Boneca [39] and Inamury [34, 40].
Źródło:
Wiadomości Chemiczne; 2015, 69, 7-8; 513-540
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
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
Tytuł:
Niekonwencjonalne metody zagospodarowania dwutlenku węgla
Unconventional methods of carbon dioxide management
Autorzy:
Smoliński, A
Świądrowski, J.
Howaniec, N.
Powiązania:
https://bibliotekanauki.pl/articles/340573.pdf
Data publikacji:
2009
Wydawca:
Główny Instytut Górnictwa
Tematy:
dwutlenek węgla
zagospodarowanie
synteza chemiczna
hydraty
synergia elektrowni i rafinerii
carbon dioxide
chemical synthesis
management
hydrates
synergy of coals and refineries
Opis:
Wzrost zapotrzebowania na energię oraz brak alternatywy dla paliw kopalnych, jako głównego surowca do jej produkcji, wymusza działania zmierzające do ograniczania emisji dwutlenku węgla oraz poszukiwanie metod jego zagospodarowania. W artykule przedstawiono uzupełniające dla metod składowania w formacjach geologicznych sposoby zagospodarowania dwutlenku węgla, bazujące na koncepcjach synergii elektrowni węglowych, elektrowni jądrowej/wiatrowej/słonecznej i rafinerii wytwarzającej paliwa syntetyczne, metodach wykorzystywania dwutlenku węgla w syntezie chemicznej oraz składowania w postaci hydratów.
An inereasing cnergy demand and the unauestionable leading role of fossil fuels in the energy mix enforce activities aiming at carbon dioxidc emission reduction and new methods of its disposal. In the paper methods complementary to the seauestration of carbon dioxide in geological formations based on the concepts of synergy between coal power plants, nu clear/wind/solar power plants and refineries producing synthetic fuels as well as methods of carbon dioxide utilization in chemical synthesis and storage in the form of hydrates are presented.
Źródło:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa; 2009, 4; 85-99
1643-7608
Pojawia się w:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa
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:
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:
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
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