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Tytuł:
Rola metali w rozwoju choroby Alzheimera i Parkinsona
The role of metals in development Alzheimer's and Parkinson's diseases
Autorzy:
Żygowska, Justyna
Szymańska, Aneta
Powiązania:
https://bibliotekanauki.pl/articles/2057913.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
choroba neurodegeneracyjna
jony metali
β-amyloid
białka amyloidogenne
choroba Alzheimera
choroba Parkinsona
neurodegenerative diseases
amyloidogenic proteins
amyloid β
metal ions
Alzheimer's disease
Parkinson disease
Opis:
Neurodegenerative diseases are the consequence of progressive brain degeneration caused by the death of nerve cells. Many factors that influence the neurodegeneration development are still not fully known. A lot of studies indicate the contribution of metal ions in this process. Copper, zinc, and iron are trace elements essential for proper functioning of the body. They are part of many enzymes participating in the transmission of the nerve signals, electrons transport, neurotransmitters and nucleic acids synthesis, and oxygen storage. Disorder of metals homeostasis leads to the development of severe diseases and nervous system degenerations. An excess of copper and iron ions causes a significant increase in cellular oxidative stress. Metals catalyze the reactions of free radicals formation that destroy proteins, lipids, and nucleic acids. High concentration of copper and iron ions were found in the deposits of amyloidogenic proteins. Amyloid β (Alzheimer disease) and α synuclein (Parkinson disease) have ions binding chain structures. The metal-protein interaction increases oligomerization speed in vitro. A lot of evidence suggests that the disorder of Cu, Zn and Fe homeostasis accelerates the progress of brain neurodegeneration. Human organism contains many metals, which are not needed for the proper functioning of the body, e.g. aluminum. Al binds to nucleic acids causing an increase in cellular oxidative stress and initiating proteins oligomerization. The presence of aluminum is also considered to be disadvantageous for the nervous system. The lack of medicines for neurodegenerative diseases forces us to search for new therapies. The development of degenerations could be slowed down by chelators of toxic metals, but first, these diseases must be better understood. Adverse effects of high concentration of metal ions on brain functioning are not fully known. This knowledge is necessary to find effective drugs.
Źródło:
Wiadomości Chemiczne; 2022, 76, 1-2; 1-25
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Opracowanie regresyjnych metod obliczania zasadniczych parametrów alternatywnych toksycznych efektów ksenobiotyków
Development of the regression methods for calculating the essential characteristics of alternative toxic effects of xenobiotics
Autorzy:
Zinkovskyy, Y. G.
Zhuk, O. V.
Oloś, G.
Zhuk, M.
Jabłecki, R.
Powiązania:
https://bibliotekanauki.pl/articles/951562.pdf
Data publikacji:
2011
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
efekt toksyczny
metody regresyjne
jony miedzi
jony niklu
jony amonu
efekt podostry
toxic effect
regression methods
copper
nickel
ammonium ions
subacute effect
Opis:
Na podstawie wykorzystania aparatu matematycznego modelu molekularnego dynamiki alternatywnych efektów ksenobiotyków zaproponowano szereg metod regresyjnych do analizy danych doświadczalnych. Dla grup zwierząt doświadczalnych Cypris pubem, Brachidanio rerio i Psevdorazbora parwa dla obecnych w wodzie różnych, stałych w czasie stężeń jonów miedzi, niklu i amonu określone zostały: graniczny (Tg) i charakterystyczny (τ) czas efektu, stężenia graniczne (minimalne toksyczne) toksykantów (Cg), wewnętrzne aktywności tworzących się kompleksów „ksenobiotyk - makromolekuły organizmu" (α) i pozorne stałe szybkości równowagi procesu ich rozpadu (Kapp). Zaproponowano szereg metod wykrywania wpływu efektów podostrych na całokształt dynamiki toksycznego działania ksenobiotyków przy ich małych stężeniach w środowisku wodnym.
On the basis of the use of mathematical model of the molecular dynamics of alternative effects ot xenobiotics, a number of regression methods to analyze experimental data has been proposed. Three groups of experimental animals were used: Cypris pubera, Brachidanio rerio and Pseudorazbora panva. Ali of them were examined for yarious, fixed in time concentrations of ions of copper, nickel and ammonium in aquatic environment. Yalues of: threshold (Tg) and characteristic (τ) times of the effect, the concentration limits (minimum toxic) of toxicants (Cg), internal activity of the "xenobiotic -macromolecule of organisms" formed complexes (α) and apparent constants rates of the balance of their decay (Kapp) were set out. Several methods of detecting the influence of subacute effects on the overall dynamics of toxic effect of xenobiotics at its Iow concentrations in the aquatic environment were proposed.
Źródło:
Chemistry-Didactics-Ecology-Metrology; 2011, 16, 1-2; 29-34
2084-4506
Pojawia się w:
Chemistry-Didactics-Ecology-Metrology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weryfikacja metodyki badawczej dotyczącej oznaczania sodu w wodach podziemnych z zastosowaniem techniki emisyjnej spektroskopii atomowej, w okresie wiosennym i zimowym
Verification of the research methodology for the determination of sodium in groundwater using the atomic emission spectroscopy technique, in spring and winter
Autorzy:
Zielińska, Amelia
Powiązania:
https://bibliotekanauki.pl/articles/2175620.pdf
Data publikacji:
2021
Wydawca:
Poltegor-Instytut Instytut Górnictwa Odkrywkowego
Tematy:
wody podziemne
jony sodu
emisyjna spektrometria atomowa
groundwater
sodium ions
atomic emission spectrometry
Opis:
W artykule przedstawiono wyniki monitorowania zawartości jonów sodu w wodach podziemnych w zależności od pory roku (wiosna, zima), z dwóch rodzajów studni: kopanej oraz głębinowej, Scharakteryzowano punkty poboru próbek. Opracowano metodykę badawczą na podstawie normy PN-ISO 9964-3:1994, którą stosowano do oznaczania zawartości jonów sodu.
The paper presents the results of monitoring sodium content in groundwater, depending on the season (spring, winter) from two types of wells: dug and deep well. Sampling points were characterized. The research methodology was developed on the basis of the PN-ISO 9964-3:1994 standard, which was used to determine the content of sodium ions.
Źródło:
Górnictwo Odkrywkowe; 2021, 62, 4; 28--36
0043-2075
Pojawia się w:
Górnictwo Odkrywkowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of monovalent and divalent ions in coal gasification brine on the froth entrainment and flotation kinetics of anthracite coal
Autorzy:
Zheng, Kaidi
Bu, Xiangning
Zhou, Shaoqi
Zhang, Jing
Shao, Huaizhi
Sha, Jie
Xie, Guangyuan
Powiązania:
https://bibliotekanauki.pl/articles/1845216.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal gasification brine
salts ions
coal flotation
entrainment
flotation kinetics
DLVO theory
Opis:
Water plays a critical role in various stages of flotation, which brings a lot of pressure to the flotation processing plants resided in dry areas. In this regard, it will be of significance to explore the feasibility of using wastewater resources in mineral flotation. Coal gasification brine (CGB) that contains a high concentration of salts becomes the subject of interest of this study. In this study, a synthetic CGB solution, which was prepared by adding NaCl, MgCl2, and CaCl2 to ultrapure water based on the composition of salts in a real CGB, was used in the flotation of anthracite coal. The comparison results based on the first-order model showed that flotation in the presence of the synthetic CGB solution gave a higher flotation selectivity (SI =7.086) than that of flotation in ultrapure water (SI=3.545). Water recoveries and average bubble sizes in the froth showed that the addition of the three salt ions (Na+, Mg2+, and Ca2+) was conducive to diminishing the entrainment of gangue materials as a result of the reduction of water reporting to the froth. Additionally, the zeta potentials and induction time measurements indicated that only divalent ions of Ca2+ and Mg2+ significantly compressed the double electrical layer and enhanced the attachment between bubbles and coal particles according to DLVO theory, which was further confirmed by the calculation of interaction energy between coal and bubbles. The findings of the present work may promote the use of CGB as a potential water resource in coal flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 960-974
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of lead ions from acid aqueous solutions and acid mine drainage using zeolite bearing tuff
Autorzy:
Zendelska, A.
Golomeova, M.
Golomeov, B.
Krstev, B.
Powiązania:
https://bibliotekanauki.pl/articles/204844.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
adsorption
acid mine drainage
zeolite bearing tuff
lead ions
equilibrium studies
Sasa mine
Opis:
The adsorption of lead ions onto a zeolite bearing tuff (stilbite) from synthetic acid aqueous solution and acid mine drainage taken from Sasa mine, Macedonia, is elaborated in this paper. The results present that adsorption occurs efficiently in both of cases. The physical and chemical properties of the used natural material, zeolite bearing tuff, are characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy. The concentration of metal ions in solution before and after treatment is obtained by AES-ICP. The effectivity of zeolite bearing tuff is determined through a series of experiments under batch conditions from single ion solutions, whereby the main parameters are the effects of initial pH of solution, mass of adsorbent, initial metal concentration in solution, contacting time and competing cations. The maximum capacity of zeolite bearing tuff for removal of lead ions from solution is determined by equilibrium studies. The experimental obtained data are fitted with Freundlich and Langmuir adsorption models. The experimental data are better fitted with Langmuir adsorption isotherm. Zeolite bearing tuff is effective adsorbent for treating acid mine drainage. The results showed that 99% of lead ions are removed from acid mine drainage, i.e. the concentration of lead ions from 0.329 mg/dm3 decrease to 0.002 mg/dm3. The pH value of acid mine drainage from 3.90 after treatment with zeolite bearing tuff increases to 5.36.
Źródło:
Archives of Environmental Protection; 2018, 44, 1; 87-96
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex Technology of Sewage Purification from Heavy-Metal Ions by Natural Adsorbents and Utilization of Sewage Sludge
Autorzy:
Zasidko, Iryna
Polutrenko, Myroslava
Mandryk, Oleg
Stakhmych, Yuliia
Petroshchuk, Nataliia
Powiązania:
https://bibliotekanauki.pl/articles/124975.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
heavy metal ions
adsorption
thermal pyrolysis
modifying additive
ceramic mixture
Opis:
The aspects of complex technology of sewage purification and utilization of purification sludge were investigated in the article. The authors substantiated the possibility of purifying sewage from heavy-metal ions by means of zeolite and utilizing sewage sludge in bricks production. The adsorption capacity of the zeolite from Sokyrnytsia deposit was studied for cupric and manganese ions in relation to its fractional composition. The comparative effectiveness studies of heavy metals adsorption by natural zeolite and anthracite were carried out. The optimal sorption parameters of these ions were selected based on the investigation results of their adsorption dynamics in the Cu2+ and Mn2+ solutions. The prospects of sewage sludge utilization by means of its thermal pyrolysis at the temperatures of 600-700°С were studied. The modifying additive was obtained, which can be added to the ceramic mixture and increase the porosity, reduce the density and decrease the thermal conductivity of course solid bricks.
Źródło:
Journal of Ecological Engineering; 2019, 20, 5; 209-216
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanizm sorpcji jonów metali w hydrożelu chitozanowym - badania kalorymetryczne
Mechanism of metal ion soprtion in chitosan hydrogel - calorimetric studies
Autorzy:
Zarzycki, R.
Modrzejewska, Z.
Kierzkowska-Pawlak, H.
Sujka, W.
Powiązania:
https://bibliotekanauki.pl/articles/127430.pdf
Data publikacji:
2009
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
chitozan
adsorpcja
jony metali
ciepło reakcji
chitosan
adsorption
metal ions
heat reaction
Opis:
Przedstawiono kalorymetryczne badania hydrożelu chitozanowego dotyczące mechanizmu sorpcji Cu(II), Ag(I) i Ca(II). Wyznaczono ciepła reakcji sorpcji tych jonów. Proces ten prowadzono dla maksymalnego stężenia danego jonu. Z pomiarów efektu cieplnego wynika, iż dla jonów Cu(II) i Ag(I) proces sorpcji ma charakter chemiczny (chemisorpcja). Efekt cieplny jest rzędu kilkudziesięciu kJ/mol. Natomiast jony Ca(II), które korzystnie wpływają na organizm ludzki, nie wykazują tego efektu.
In the present research, studies were performed to determine the character of adsorption of Ca(II), Cu(II), Ag(I) ions in chitosan. The studies were carried out for chitosan hydrogel. The character of sorption was determined on the basis of calorimetric studies. The heat of reaction was measured during the sorption of individual ions. The process of adsorption was carried out for a maximum ion concentration. It follows from the measurement of the heat of sorption for Cu(II) and Ag(I) ions that the sorption process has a chemical character, which is shown by a measurable thermal effect of the order of dozens kJ/mol. It is interesting that Ca(II) ions which have an advantageous influence on living organisms, do not reveal this effect.
Źródło:
Proceedings of ECOpole; 2009, 3, 1; 221-227
1898-617X
2084-4557
Pojawia się w:
Proceedings of ECOpole
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Regulatory Framework of the Soviet Diplomatic Protocol. History of Formation
Autorzy:
Zakharova, Oksana
Powiązania:
https://bibliotekanauki.pl/articles/1930492.pdf
Data publikacji:
2020-06-30
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
foreign policy
diplomacy
state image
ideology
diplomatic recept ions
foreign visits
Opis:
The concept of “diplomacy” combines the foreign policy activities of state leaders and supreme authorities. At various stages of the development of society the methods and means of diplomacy changed. In the Middle Ages the protocol is the rules of paperwork and archiving. Subsequently ceremonial issues began to be attributed to the diplomatic protocol. Currently the diplomatic protocol is a set of generally accepted norms, traditions and conventions that are observed in international communication. The purpose of the study is to analyze the evolution of the Soviet protocol as an instrument of the state’s foreign policy based on the analysis of regulatory documents. The novelty of the study lies in the fact that the author considers the diplomatic legal culture as a component of the image of the state, in which ideology influenced all aspects of society, including the rules of communication between a Soviet citizen and foreign partners. It was revealed that the employees of the Protocol Department of the People’s Commissariat for Foreign Affairs (PCFA), and primarily its head D.T. Florinsky (repressed in 1934) and V.N. Barkov (repressed in 1941, rehabilitated in 1958), were able to “reconcile”, as evidenced by regulatory documents, the European diplomatic protocol with the norms of Soviet ideology. Through its work the Protocol Department tried to destroy the idea of the USSR as an “empire of evil”; it was part of the positive image of the USSR, like the Bolshoi Theater, Soviet sports and Russian literature. As an actor in world politics the Soviet Union could not but accept the main provisions of the Vienna Convention on Diplomatic Relations. Ignoring the international norms of the protocol is a denial of equality, sovereignty, territorial integrity of the state, and as a result, loss of reputation in the eyes of the world community.
Źródło:
Krakowskie Studia Małopolskie; 2020, 2(26); 150-163
1643-6911
Pojawia się w:
Krakowskie Studia Małopolskie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biosorbenty stosowane w usuwaniu jonów metali ciężkich z zanieczyszczonego
Biosorbents for heavy metal-contaminated environment
Autorzy:
Zabochnicka-Świątek, M.
Powiązania:
https://bibliotekanauki.pl/articles/1208156.pdf
Data publikacji:
2013
Wydawca:
Stowarzyszenie Inżynierów i Techników Przemysłu Chemicznego. Zakład Wydawniczy CHEMPRESS-SITPChem
Tematy:
biosorbent
biosorpcja
bioakumulacja
jony metali ciężkich
biosorbents
biosorption
bioaccumulation
heavy metal ions
Opis:
Omówiono możliwości wykorzystania wybranych biosorbentów do usuwania jonów metali ciężkich z zanieczyszczonego środowiska. Zaprezentowano najważniejsze biologiczne materiały stosowane w procesach biosorpcji i bioakumulacji oraz sposoby ich modyfikacji. Dokonano przeglądu możliwości praktycznego zastosowania wybranych biosorbentów.
The application of selected biosorbents for heavy metal-contaminated environment was discussed. The most important biological materials for biosorption and bioaccumulation processes and modification methods of biomass were presented. Practical application of selected biosorbents was discussed.
Źródło:
Chemik; 2013, 67, 10; 971-978
0009-2886
Pojawia się w:
Chemik
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of biomass (Chlorella vulgaris, Scenedesmus armatus) concentrations on Zn2+, Pb2+ and Cd2+ biosorption from zinc smelting wastewater
Wpływ stężenia biomasy (Chlorella vulgaris, Scenedesmus armatus) na biosorpcję Zn2+, Pb2+ i Cd2+ ze ścieków z ocynkowni
Autorzy:
Zabochnicka-Świątek, M.
Rygała, A.
Powiązania:
https://bibliotekanauki.pl/articles/297720.pdf
Data publikacji:
2017
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
algae
Chlorella vulgaris
Scenedesmus armatus
heavy metal ions
sorption
modified microalgal biomass
jony metali ciężkich sorpcja
modyfikowana biomasa glonów
Opis:
Non-modified and chemically modified algal biomass of Chlorella vulgaris and Scenedesmus armatus were chosen to examine their Zn2+, Pb2+ and Cd2+ sorption activity. The dry biomass was chemically modified with 1M HNO3 in order to determine the influence of acid- -treatment on the heavy metal ions removal rate. The heavy metal uptake process was found to be rapid and very efficient. The sorption process of heavy metals is highly pH-dependent. It influences heavy metal forms in the solution, and functional groups located on the cell surface. The effectiveness of biosorption depends also on the biomass concentration and its modifications. The highest adsorption capacities of both, Chlorella vulgaris and Scenedesmus armatus towards zinc, lead and cadmium ions were found for the lowest sorbent concentrations. Batch experiments showed that the differences between uptake by non-modified and acid-modified biomass are relatively small. It can be due to the fact that non-modified algal biomass exhibits high sorption capacity.
Celem badań była ocena wydajności biosorpcji Zn2+, Pb2+ i Cd2+ pochodzących z ocynkowni przez modyfikowaną i niemodyfikowaną biomasę glonów z rodzaju Chlorella vulgaris i Scenedesmus armatus. Powietrznie suchą biomasę glonów poddano chemicznej modyfikacji przy użyciu 1M HNO3 w celu oceny wpływu kwaśnej modyfikacji na szybkość usuwania wybranych jonów metali ciężkich. Stwierdzono, że proces usuwania jonów metali ciężkich zachodził z dużą wydajnością w krótkim czasie. Wydajność sorpcji jonów metali ciężkich zależała od odczynu środowiska, który miał wpływ na dostępność grup funkcyjnych na powierzchni sorbentu. Efektywność procesu biosorpcji zależała również od stężenia biomasy i jej modyfikacji. Najwyższą pojemność sorpcyjną odnotowano po użyciu sorbentu w najniższym stężeniu. Na podstawie uzyskanych rezultatów badań stwierdzono, że zastosowanie biomasy modyfikowanej i niemodyfikowanej nie wpłynęło znacząco na różnice w wydajności sorpcji jonów metali ciężkich. Mogło to być spowodowane tym, że biomasa niemodyfikowana posiadała wyjściowo dużą pojemność sorpcyjną.
Źródło:
Inżynieria i Ochrona Środowiska; 2017, 20, 2; 211-220
1505-3695
2391-7253
Pojawia się w:
Inżynieria i Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on different behavior and mechanism of Ca(II) and Fe(III) adsorption on spodumene surface
Autorzy:
Yu, F.
Wang, Y.
Wang, J.
Xie, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110230.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
spodumene surface
calcium ions
iron ions
adsorption mechanism
DFT calculation
Opis:
Behavior and mechanism of Ca2+ and Fe3+ adsorption on spodumene surface were investigated by micro flotation tests, zeta potential measurements, and density functional theory (DFT) calculation methods. The micro flotation tests showed that Ca2+ and Fe3+ activated the flotation of spodumene remarkably. However, the effect of Fe3+ was more significant than that of Ca2+. Additionally, Fe3+ significantly changed the zeta potential of spodumene while Ca2+ showed a little change. Meanwhile, the calculated adsorption energy of Fe3+ on spodumene surface was much greater than that of Ca2+ indicating that Fe3+ is more apt to be adsorbed on spodumene surface than Ca2+. The value of bond population in Ca-O illustrated that the bond of Ca-O consists of partial covalent proportion and some ionic component. On the contrary, the bond of Fe-O showed a relatively strong covalent property. The partial density of states (PDOS) of free Ca/Fe and the reacted O atom on spodumene (110) surface before and after the adsorption showed that Fe 3d orbital and O 2p orbital formed hybridization. The density of states (DOS) near the Fermi level of spodumene surface after adsorption with Fe3+ was much stronger than that with Ca2+.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 535-550
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ag+/S2O8 2– system for the degradation of aqueous flutriafol
Autorzy:
Yang, H.
Zhou, W.
Yang, L.
Deng, J.
Hu, Q.
Wei, H.
Au, C.
Yi, B.
Powiązania:
https://bibliotekanauki.pl/articles/207760.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chemical analysis
degradation
free radicals
metal ions
molecular orbital
transition metals
analiza chemiczna
degradacja
wolne rodniki
jony metali
orbital molekularny
metale przejściowe
Opis:
The degradation of flutriafol in aqueous persulfate (S2O82–) system in the presence of selected transition metal ions was investigated. In the presence of Ag+ or Fe2+, flutriafol degradation occurs, whereas in the presence of Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Bi3+ ions, the degradation is less than 15%. The Ag+/ S2O82– aqueous system being the most effective was adopted for experimental and theoretical investigations. It was confirmed that pH of 3.0 is the most suitable, and that both · SO4–and ·OH– radicals are the main active species to afford flutriafol degradation, with the former contributes more than the latter. To elucidate degradation mechanism, molecular orbital calculations were performed and reaction intermediates identified by GC/MS and HPLC/MS/MS analyses. Three degradation pathways are proposed that involve the cleavage of C–N and C–C bonds as a result of ·SO4– attack, as well as the formation of hydroxylated products due to · OH radicals.
Źródło:
Environment Protection Engineering; 2018, 44, 2; 57-72
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of uranium(VI) from aqueous solution by rice husk
Autorzy:
Xia, L.
Li, R.
Xiao, Y.
Zheng, W.
Tan, K.
Powiązania:
https://bibliotekanauki.pl/articles/208201.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wheat straw
biosorption
uranium
ions
biosorpcja
słoma zbożowa
uran
jony
Opis:
Basic aspects of uranium adsorption by rice husk have been investigated. The influences of various experimental parameters such as pH, time, adsorbent dosage, rice husk size, temperature and various concentrations of uranium on uptake were evaluated. The thermodynamics and kinetics of adsorption were analyzed by FT-IR and SEM. The adsorption capacity for uranium on rice husk increased upon increasing initial concentration of uranium and temperature, while decreased with the increase of the amount of rice husk. Maximum uranium adsorption was observed at pH = 3 and particle size between 120 μm and 150 μm. Adsorption equilibrium was achieved within 60 min. At 25 °C, the saturated adsorption capacity qmax was up to 15.14 mg/g when the initial concentration of uranium ranged from 10 to 400 mg/dm3. The adsorption of uranium followed Langmuir adsorption isotherm and according to quasi-second order kinetic equation. The calculated values of ΔH°, ΔS°, and ΔG° indicated that the biosorption process was endothermic and spontaneous. Based on FT-IR spectra it may be concluded that hydroxyl, carbonyl, P–O and Si=O groups are the main active sites.
Źródło:
Environment Protection Engineering; 2017, 43, 4; 41-53
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Regulacja aktywności katalitycznej rybozymów HDV oraz deoksyrybozymów za pomocą antybiotyków i jonów metali
Regulation of the catalytic activity of HDV ribozymes and deoxyribozymes with antibiotics and metal ions
Autorzy:
Wrzesinski, J.
Ciesiołka, J.
Powiązania:
https://bibliotekanauki.pl/articles/171740.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
antybiotyki
rybozymy HDV
deoksyrybozymy
jony metali
antibiotics
HDV ribozymes
deoxyribozymes
metal ions
Opis:
This review article describes the results of a 15-year cooperation between the Department of RNA Biochemistry at the Institute of Bioorganic Chemistry, Polish Academy of Sciences in Poznań and the Medical Chemistry Team of the Faculty of Chemistry at the University of Wrocław, headed by Professor Małgorzata Jeżowska- -Bojczuk. A wide spectrum of antibiotics and other low molecular compounds and their complexes with Cu2+ ions have been tested as potential inhibitors of the HDV ribozyme catalytic reaction. Unexpectedly, it has been found that a number of compounds, depending on the conditions, exhibit inhibitory or stimulatory properties, i.e. they act as modulators of the RNA catalysis process. It was found that the effect of stimulation / inhibition of the catalytic activity of the HDV ribozyme is closely related to the degree of protonation of the antibiotics under study in given conditions. Their ability to inhibit catalysis also increases after binding the Cu2+ cation. In an environment with a higher pH, antibiotics usually stimulate the cleavage reaction, as at least some of their nitrogen centers are allowed to participate in the catalysis reaction, as proton acceptors / donors or a catalytic metal ion coordination site. During the study of one of the antibiotics, bacitracin, it was also observed that it exhibits nucleolytic properties with RNA and DNA molecules. The discovery of the hydrolytic properties of bacitracin extended the potential use of this antibiotic in antiviral therapy with the aim to destroy undesired nucleic acids in the cell. To search for DNAzymes catalyzing RNA hydrolysis, the in vitro selection method was used. In the selection experiment aimed at obtaining DNAzymes active in the presence of Cd2+ ions, variants belonging to the family of DNAzymes 8–17 previously described in the literature were obtained. Analysis of their properties showed that not only Cd2+ but also Zn2+ and Mn2+ ions support catalysis, therefore the site of catalytic metal ion coordination is not highly specific. The DNAzymes obtained in the second selection experiment showed an optimum of catalytic activity in the pH range of 4.0–4.5 and were inactive at a pH higher than 5.0. Interestingly, they do not require the presence of any divalent metal ions as cofactors in the catalysis reaction. The obtained results broaden the repertoire of DNAzymes which operate under non-physiological conditions and bring new information on the possible mechanisms of reactions catalyzed by nucleic acids.
Źródło:
Wiadomości Chemiczne; 2018, 72, 7-8; 397-415
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport cząstek koloidalnych z zaadsorbowanymi jonami arsenu przez mineralne złoże porowate
Transport of colloidal particles with arsenic ions adsorbed on the colloidal surfaces through mineral porous bed
Autorzy:
Wróbel, I.
Polowczyk, I.
Sadowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1819759.pdf
Data publikacji:
2009
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
jony arsenu
złoża mineralne
cząstki koloidalne
colloidal particles
arsenic ions
minerals
Opis:
Obecność odpadów przemysłowych w środowisku naturalnym staje się coraz bardziej zauważalnym problemem w ochronie środowiska. Za główne źródło ich powstawania, uważa się przemysł wydobywczy i przetwórstwa kopalin. W wyniku prowadzenia procesów wzbogacania, bądź procesów hutniczych, powstają odpady deponowane na hałdach, które w znaczący sposób przyczyniają się do zanieczyszczeń wód gruntowych. Dzieje się tak w wyniku transportu trudno rozpuszczalnych zanieczyszczeń przez naturalny polimineralny ośrodek porowaty. Zjawisko to zostało zaliczone do głównych procesów mających istotny wpływ na zanieczyszczanie wód gruntowych.
The storage of insecure industrial waste, descended from mining and metallurgical industry, has an influence on the pollution of a ground and groundwater. It is a result of migration of toxic substances into the bed of soli. The weathering processes and hydrodynamic changes in soil causes the colloidal particles formation, which are effective contaminations carriers through mineral porous media. In this paper transport of colloidal particles: synthetic hematite and natural kaolin has been investigated. The porous medias were waste from both Szklary and Złoty Stok heaps. The aim of this work is to inspect the influence of arsenate ions on the behaviour of colloidal particles in porous bed. The investigations were conducted in two ionic strengths: 5ź10-3 M KCl and 5ź10-4 M KCl, at pH 9.2-11.6. Results showed that transport of colloidal hematite was facilitated, when arsenic ions were adsorbed onto the colloid particles. Additionally, the increase of mobility of hematite was caused by a decrease of ionic strength. In the case of kaolin transport, the results showed an increase of kaolin particles migration without arsenic ions. These behaviour of colloidal kaolin particles into mineral bed isexplained by different surface property of kaolin particles. Results of examinations on colloidal particles of hematite and kaolin transport through column with mineral bed show, that examined mobility is conditioned with physico-chemical proprieties of colloidal particles and materials of porous bed. Studied colloids, can influence pollution of underground waters in the areas of storing of studied industrial wastes. Results of conducted measurements show, that the process of examined colloidal particles transport is influenced by presence of adsorbed arsenic ions. It is the most perceptible phenomenon in the case of the colloidal hematite, particularly for porous medium built from materials taken from the southern side of heap in Szklary and heap in Złot Stok. Additionally, influence of ion strength on quantity of transported colloidal particles through the layer of porous mineral medium was observed. When ion strength was decreasing, the thickness of the double electric layer increases on colloidal particles. It has impact on decrease of attracting interactions among particles of colloid, and also between colloidal particle and grain of mineral bed. The opposite case was noted during investigations on transportation of colloidal particles of kaolin. Adsorption of arsenic ions by particles of kaolin causes decrease of their mobility. This causes stopping of migration of arsenic ions to underground waters. The similar result is obtained when ion strength is enlarged.
Źródło:
Rocznik Ochrona Środowiska; 2009, Tom 11; 1119-1130
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 250

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