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Tytuł:
The mechanical aspect of titanium ion release after posterior instrumentation for early onset scoliosis
Autorzy:
Danielewicz, Anna
Fatyga, Marek
Wójciak-Kosior, Magdalena
Sawicki, Jan
Różańska-Boczula, Monika
Sowa, Ireneusz
Latalski, Michał
Powiązania:
https://bibliotekanauki.pl/articles/109528.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
scoliosis
metal ions
implant
titanium
mineralization
Opis:
Surgical treatment of early onset scoliosis (EOS) is connected with the risk of early and late complications. The aim of the study is to assess influence of the rod fracture on the titanium ion release (TIR) in traditional growing rods instrumentation for EOS.56 patients treated surgically due to EOS were divided into three groups: 1) a control-patients newly operated due to scoliosis, patients treated with the traditional growing rod (TGR) and TGR who had rod fracture (FGR) and required a surgical revision. Titanium quantification in blood sample, skin fragment (CT –clean tissue) andmacrosco-pically contaminated tissue located near the implant (DT –dirty tissue) was performed using high-resolution emission spectrometry with excitation in inductively coupled plasma.The mean serum titanium level in control, TGR, and FGR groups were 1.93 ± 0.8, 5.61 ± 0.23, and 4.43 ± 0.1 μg/dm3, respectively. The mean CT titanium level in control, TGR, and FGR groups were 0.0045 ± 0.001, 0.0035 ± 0.001and 0.0065 ± 6.8 mg/g, respectively. The mean DT titanium level in TGR and FGR groups was 0.59 ± 0.02, and 1.022 ± 0.03 mg/g, respectively.Implant leadsto the TIR into tissues and blood. Increasing the number of anchors increases the titanium content inthe CT TGR group. Mechanical damage to the implant has no significant effect on the increase of TIR
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 6; 1442-1449
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence and mechanism of Zn2+ on fluorite/calcite in sodium hexametaphosphate flotation system
Autorzy:
Ruitao, Liu
Dan, Liu
Ruofan, Sun
Daqian, Wang
Wenkang, Zhang
Yuebing, Liu
Shuming, Wen
Powiązania:
https://bibliotekanauki.pl/articles/2175451.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fluorite
calcite
sodium hexametaphosphate
flotation
metal ions
Opis:
Fluorite and calcite have similar surface properties and natural floatability, so their flotation separation has always been a problem faced by the beneficiation industry. The key to flotation separation is the choice of depressants. Sodium hexametaphosphate (SHMP) has a good effect on fluorite calcite selective inhibition. In this paper, the effects of Zn2+ on the selective inhibition of SHMP in the flotation process of fluorite and calcite were studied through single mineral and artificial mixed mineral flotation experiments. Solution chemical calculation, X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared spectroscopy (FT-IR) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analyses investigated the mechanism of action of Zn2+, which had the most significant negative effect on the selective inhibition of SHMP. The results show that the main components of SHMP inhibiting minerals are HPO42- and H2PO4-, which can react with Ca active sites on the mineral surface to form hydrophilic Ca(H22PO4)2 and CaHPO4, while Zn2+ The presence of HPO42- in solution resulted in the formation of stable ZnHPO4 complexes, thereby weakening the inhibitory effect of SHMP on minerals.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 151676
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Signalling: basics and evolution.
Autorzy:
Williams, Robert
Powiązania:
https://bibliotekanauki.pl/articles/1043264.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
pumps
signalling
metal ions
receptors
donors
substrates
Opis:
Signalling concerns the transfer of information from one body, a source, to another, a receiver in order to stimulate activity. The problem arises with the word information. It is defined as what is transferred in a sequence of things, say between people, e.g. words or signs. The idea of signalling between people is then obvious but it is not clear in cell biology. Information transfer, signalling, is required for the organisation of all cellular activity but we must ask what is transferred and how is it transmitted and received? Sometimes it is assumed that all information, i.e. organisation in a cell, is represented in the DNA sequence. This is incorrect. We shall show that the environment is a second source of information concerning material and energy. The receiving party from both DNA and the environment is general metabolism. The metabolism then signals back and sends information to both DNA and uptake from the environment. Even then energy is needed with machinery to send out all signals. This paper examines the way signalling evolved from prokaryotes through to man. In this process the environmental information received increased to the extent that finally the brain is a phenotypic as much as a genotypic organ within a whole organism. By phenotypic we mean it is organised by and interactive with information from the environment.
Źródło:
Acta Biochimica Polonica; 2004, 51, 2; 281-298
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on the production of glucose isomerase by Bacillus licheniformis
Autorzy:
Nwokoro, O.
Powiązania:
https://bibliotekanauki.pl/articles/778827.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
glucose isomerase
carbon sources
nitrogen sources
metal ions
Opis:
This work reports the effects of some culture conditions on the production of glucose isomerase by Bacillus licheniformis. The bacterium was selected based on the release of 3.62 mg/mL fructose from the fermentation of glucose. Enzyme was produced using a variety of carbon substrates but the highest enzyme activity was detected in a medium containing 0.5% xylose and 1% glycerol (specific activity = 6.88 U/mg protein). Media containing only xylose or glucose gave lower enzyme productivies (specific activities= 4.60 and 2.35 U/mg protein respectively). The effects of nitrogen substrates on glucose isomerase production showed that yeast extract supported maximum enzyme activity (specific activity = 5.24 U/mg protein). Lowest enzyme activity was observed with sodium trioxonitrate (specific activity = 2.44 U/mg protein). In general, organic nitrogen substrates supported higher enzyme productivity than inorganic nitrogen substrates. Best enzyme activity was observed in the presence of Mg2+ (specific activity = 6.85 U/mg protein) while Hg2+ was inhibitory (specific activity = 1.02 U/mg protein). The optimum pH for best enzyme activity was 6.0 while optimum temperature for enzyme production was 50oC.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 3; 84-88
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of macrocycle compounds for metal ions separation and removal - a review
Autorzy:
Walkowiak, W.
Ulewicz, M.
Kozłowski, C. A.
Powiązania:
https://bibliotekanauki.pl/articles/346971.pdf
Data publikacji:
2002
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Tematy:
macrocycles
crown ethers
lariat ethers
metal ions
separation
Opis:
A review is presented on macrocyclic compounds novel reagents for metal ions separation and removal in solvent extraction, transport through liquid membranes, and flotation processes. As macrocyclic compounds were used such chemicals as non-ionizable crown ethers, ionizable crown ethers (lariat ethers), calixarenes, and acyclic polyethers. Many literature data as well our own recent research data will be reported on metal ions removal and separation.
Źródło:
Ars Separatoria Acta; 2002, 1; 87-98
1731-6340
Pojawia się w:
Ars Separatoria Acta
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surfactant-aided membrane process for copper ion removal from water solutions
Autorzy:
Klimonda, A.
Kowalska, I.
Powiązania:
https://bibliotekanauki.pl/articles/208193.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
copper
anionic surfactants
metal ions
miedź
surfaktant
roztwór wodny
Opis:
The usefulness of micellar-enhanced ultrafiltration (MEUF) for copper ion removal was evaluated. The experiments were performed in a semi-pilot installation in a cross-flow regime with the use of ultrafiltration modules (5 kDa and 10 kDa). The first stage of the tests included copper ion removal in the classic UF process. During the next step, anionic surfactant (sodium dodecylbenzenesulfonate, SDBS) was added to the feed solution in a wide range of concentrations. The effect of copper and surfactant concentrations on separation efficiency and permeate flux was evaluated. It was found that MEUF enables high copper ion removal. Depending on surfactant concentration in the feed solution, the average copper concentration in the permeate was in the range from 0.02 to 0.08 mM (feed solution 0.79 mM). Surfactant rejection was strongly dependent on its concentration in the feed; the highest retention was obtained when surfactant was in the form of micelles, i.e., for concentrations exceeding the CMC.
Źródło:
Environment Protection Engineering; 2018, 44, 1; 141-152
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanism of Ca2+/Fe3+-based synergistic activation of quartz
Autorzy:
Liu, Rongxiang
Yang, Zhanfeng
Li, Jie
Li, Qiang
Wang, Zhenjiang
Luo, Xiaofeng
Powiązania:
https://bibliotekanauki.pl/articles/2200345.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quartz
flotation
co-activation
metal ions
sodium dodecyl sulfonate
Opis:
Although the flotation behaviors of iron concentrate and quartz are significantly different, quartz is the primary factor that affects the quality of iron concentrate. The flotation mechanism of quartz in the presence of mixed cationic Ca2+/Fe3+-co-activated SDS catcher was studied by conducting flotation tests with pure quartz mineral. The solution chemical calculation method, zeta potential calculation method, Fourier transform infrared (FT-IR) spectroscopy technique, X-ray photoelectron spectroscopy (XPS) technique, and other techniques were used to conduct the studies. The results showed that the maximum Ca2+/Fe3+-based synergistic activation of the flotation recovery process could be achieved in a certain range of pH values when three different activators were added sequentially. Analysis of the zeta potential values revealed that the Ca2+/Fe3+-activated quartz surface improved the extent of positive electricity generated and enhanced the SDS adsorption ability of the quartz surface. Results obtained using the FT-IR technique revealed that Ca2+/Fe3+ exerted a synergistic effect, and the adsorption process exploited the single oxygen bond interactions in the monovalent hydroxyl complex Ca(OH)+ and the double oxygen bond interactions in the Fe(OH)3 precipitates. Results obtained using the XPS technique revealed that the synergistic effect exerted by Ca2+/Fe3+ was significantly stronger than that exerted by Ca2+ or Fe3+ alone. The stable Fe-based six-membered chelate ring was formed on the surface of quartz when Fe3+ was the activator, and the chain-like Ca-based complex was formed when Ca2+ was the activator. The adsorption process on the surface of quartz proceeded following chemical as well as physical adsorption pathways. The results revealed that Ca(OH)+ and Fe(OH)3 played prominent roles during the activation of quartz surfaces in the presence of Ca2+/Fe3+.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 1; art. no. 162262
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metalotioneiny i motywy policysteinylowe : oddziaływanie z jonami metali
Metallothioneins and polythiol motifs : interactions with metal ions
Autorzy:
Krzywoszyńska, K.
Kozłowski, H.
Powiązania:
https://bibliotekanauki.pl/articles/171939.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
metalotioneiny
motywy policysteinylowe
jony metali
metallothioneins
polythiol motifs
metal ions
Opis:
Many of biochemical paths and processes require some metal ions to occur. There are also known the negative effects of the presence of metal ions in the organism. The both sides of metal ions interactions on the living organism require specific regulations and cannot be left without supervision and control of the organism itself. One of the strategy to keep the control on metal ions are cystein-rich proteins that play crucial role in detoxication of metal ions that are dangerous for human organism as well as they help to maintain homeostasis of essential metal ions. Matallothioneins are one of the well known, but still not fully understood, cysteine- rich proteins. They are small proteins but may contain up to 30% of cysteine residues in the sequence, and what makes them very special from chemical point of view - all of the thiols present there are reduced [1]. This property makes these proteins very tempting for coordination of various metal ions. The most efficient binding to metallothionein is observed for the ions belonging to a Group 11 and 12. Cu+, Zn2+ and Cd2+ represent these metal ions [2]. Besides of the lack of disulfide bridges, metallothioneins show also the absence or low amount of aromatic amino acid residues in the sequence [1]. Studies of the metallothioneins and their isoforms among different organisms show that the position of cysteine residues is very conservative [3]. Considering this aspect of metallothionein structure, some specific motifs of cysteine residues arrangement can be found in the sequence of these proteins. Most of the common polythiol motifs are CXC, CXXC, CXXXC, CC – where C is a cysteine residue and X is random α-amino acid residue (other than cysteine) [3–5]. The influence of the cysteine residues organization on the specificity of metal ions binding was intensively studied. The differences observed for specificity of metal ions binding by metallothioneins and selected polythiol motifs are reviewed in this paper – with strong emphasis on the effect of the cysteine residues topography.
Źródło:
Wiadomości Chemiczne; 2018, 72, 7-8; 383-395
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Equilibrium and kinetic studies on the removal of heavy metal ions with natural low-cost adsorbents
Autorzy:
Varank, G.
Demir, A.
Bilgili, M. S.
Top, S.
Sekman, E.
Yazici, S.
Erkan, H. S.
Powiązania:
https://bibliotekanauki.pl/articles/207257.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorbents
adsorption
bentonite
dyes
heavy metals
kinetics
metal ions
water treatment
heavy metal removal
heavy metal ions
heavy metals ions removal
adsorbenty
adsorpcja
bentonit
barwniki
metale ciężkie
kinetyka
jony metali
usuwanie jonów metali ciężkich
uzdatnianie wody
Opis:
Adsorption isotherms and kinetics of the removal of heavy metal ions (Ni, Pb, Zn) from aqueous solutions by natural adsorbents (zeolite, bentonite, clay) were investigated in a lab-scale batch study. The effect of various parameters such as adsorbent dosage, initial concentration of heavy metal ions, temperature, and agitation time were studied to optimise the conditions. Under those optimized conditions (180 rpm agitation rate, 120 min agitation time, pH 4.0, 298 K, 100 mg/dm3 initial adsorbate concentration), the removal percentages of heavy metal ions for natural adsorbents have been determined. The adsorption mechanisms and characteristic parameters of the process were analyzed by two and three parameter isotherm models (Langmuir, Freundlich, Temkin, Redlich-Peterson, Toth and Sips), and kinetic models (Lagergren's pseudo-first order, Ho and McKay's pseudo-second order). Adsorption thermodynamics of heavy metal ions (changes of standard enthalpy, entropy and free energy) on zeolite, bentonite and clay were also studied at 298,318 and 338 K.
Źródło:
Environment Protection Engineering; 2014, 40, 3; 43-61
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Principles and applications of solvent sublation - a review
Autorzy:
Sobianowska, K.
Walkowiak, W.
Kozłowski, C.
Powiązania:
https://bibliotekanauki.pl/articles/346991.pdf
Data publikacji:
2010
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Tematy:
solvent sublation
ion flotation
adsorptive bubble separations
metal ions
organic compounds
Opis:
This article reviews more than 50 references covering the solvent sublation as one of the adsorptive bubble separation methods for organic and inorganic coumpounds removal from aqueous solutions, which were published last 50 years. The solvent sublation is very simple, effective and fast process for removal and separation of chemical compounds from dilute aqueous solutions and can be treated as preconcentration method in their analytical determination. This review concerns the fundamentals of solvent sublation process and desribes the factors determinating the process (temperature, composition of initial aqueous solution, pH, ionic strength, surfactants and ligands presence, organic solvent presence with additives and gas bubble generation). The examples of metal ions selective removal (Table 1) and organic coupounds removal (Table 2) are shown.
Źródło:
Ars Separatoria Acta; 2009-2010, 7; 23-38
1731-6340
Pojawia się w:
Ars Separatoria Acta
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cloning, purification and enzymatic characterization of recombinant human superoxide dismutase 1 (hSOD1) expressed in Escherichia coli
Autorzy:
Lin, Feng
Yan, Dandan
Chen, Yawen
E, Fletcher
Shi, Haifeng
Han, Bangxing
Zhou, Yang
Powiązania:
https://bibliotekanauki.pl/articles/1038395.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
superoxide dismutase 1
Escherichia coli
soluble expression
metal ions
catalytic activity
Opis:
Superoxide dismutase 1 (SOD1) is a metalloenzyme that catalyzes the disproportionation of superoxide into molecular oxygen and hydrogen peroxide. In this study, the human SOD1 (hSOD1) gene was cloned, expressed and purified. The hSOD1 gene was amplified from a pool of Bxpc3 cell cDNAs by PCR and cloned into expression vector pET-28a (+). The recombinant soluble hSOD1 was expressed in E. coli BL21 (DE3) at 37°C and purified using nickel column affinity chromatography. Soluble hSOD1 was produced with a yield of 5.9 μg/mL medium. As metal ions can have a certain influence on protein structure and activity, we researched the influences of different concentrations of Cu2+ and Zn2+ on hSOD1 activity at induction and the time of activity detection. The results implied that Cu2+ and Zn2+ do not enhance SOD1 expression and solubility; they can, however, improve the catalytic activity at induction. Meanwhile, Cu2+ and Zn2+ also enhanced the enzyme activity at the time of detection. Furthermore, most other bivalent cations had the potential to replace Zn2+ and Cu2+, and also improved enzyme activity at the time of detection.
Źródło:
Acta Biochimica Polonica; 2018, 65, 2; 235-240
0001-527X
Pojawia się w:
Acta Biochimica Polonica
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:
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:
Removal of zinc, cadmium and nickel from mining waste leachate using walnut shells
Autorzy:
Ayala, Julia
Fernandez, Begona
Powiązania:
https://bibliotekanauki.pl/articles/208277.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metal ions
adsorption
biosorption
adsorbent
kinetics
copper
jony metali
adsorpcja
biosorpcja
kinetyka
miedź
Opis:
The removal of heavy metals from aqueous solutions using walnut shells was investigated. The effects of pH, contact time, initial metal concentration, adsorbent concentration, and co-ions were studied in synthetic solutions. Metal uptake was found to be dependent on the initial pH of the solution; the removal rate increased upon increasing pH, showing the highest affinity at pH 5–7. The amount of metal removed improved with increasing initial concentration. Increasing adsorbent dosage enhanced removal efficiency, but reduced the amount absorbed per unit mass of walnut shells. The presence of co-ions suppressed the uptake of heavy metals, divalent ions having a more negative effect than monovalentions. The adsorption of Zn, Cd and Ni onto walnut shells was found to fit Langmuir and Freundlich isotherms. The results obtained in the tests with mining waste leachate showed the potential use of walnut shells for the removal of heavy metals.
Źródło:
Environment Protection Engineering; 2019, 45, 2; 141-158
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polihistydylowe sekwencje z motywem His-tag – ich rola i biologiczne znaczenie oddziaływania z jonami metali
Polyhistidine sequences with His-tag motif – their role and biological significance of interaction with metal ions
Autorzy:
Wątły, J.
Kozłowski, H.
Powiązania:
https://bibliotekanauki.pl/articles/172145.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
histydyna
His-tag
jony metali
białka
histidine
His-tag motif
metal ions
proteins
Opis:
His-tags are specific sequences containing six to nine subsequent histydyl residues and they are used commercially in immobilized metal affinity chromatography (IMAC) as molecular ‘anchors’ that bind to a metal ion (usually nickel), immobilized by chelation with nitrilotriacetic acid (NTA) bound to a solid support [37, 38]. Consecutive histidines are the common denominator for both His-tags used in molecular biology and for quite remote biological phenomena – more than 2000 histidine- rich proteins (HRPs) are found in microorganisms including 60% and 82% of archaeal and bacterial species, respectively and their roles are not well characterized [73]. The physicochemical properties of histidine make it a versatile amino acid that influences protein conformation and enzymatic activity [15]. Many natural proteins with a His-tag domain are assigned to different functions, for example: most bacterial proteins, containing this motif are probably involved in the homeostasis of nickel ions [68, 76], while others, e.g. newly isolated peptides from the venom of the snake genus Atheris contain poly-histidyl-poly-glycyl sequences (pHpG) can act on the cardiovascular system by inhibiting snake venom metalloproteinases and affect its function by acting on specific receptors [58, 62]. His-rich motifs have been found also e.g. in Zn2+ transporters, prion proteins, His-rich glycoproteins, transcription factors or numerous copper-binding proteins [56, 67, 84]. Binding mode and the thermodynamic properties of the system depends on the specific metal ion and the histidine sequence. Despite the wide application of the His-tag for purification of proteins, little is known about the properties of metalbinding to such tag domain. Recent experimental and theoretical studies have shown that metal ions, e.g. Cu2+ can bind to various sets of imidazoles depending on the number of histidine residues that are located in His-rich sequences. The occurrence of polymorphic binding states and the formation of an α-helical structure induced by metal ion coordination suggest that proteins with a His-tag domain may serve as the dynamic site able to ‘move’ metal ions along the tag sequence [99, 100]. This might explain the frequent occurrence of such sequences in bacterial Ni2+ chaperones, which transfer the metal ion between different proteins.
Źródło:
Wiadomości Chemiczne; 2016, 70, 11-12; 1-24
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 29

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