Wyniki wyszukiwania - Biblioteka Nauki

1

The effect of lizardite on talc flotation using carboxymethyl cellulose as a depressant

100%

Deng J. , Yang S. , Zhang W. , Liu C. , Li H.

Physicochemical Problems of Mineral Processing

|

2020

|

tom Vol. 56, iss. 4

702--709

EN

The effect of lizardite on talc flotation when using carboxymethyl cellulose (CMC) as a depressant was studied by micro-flotation experiments and adsorption measurements, zeta-potential measurements, magnesium ion dissolution analysis, and solution chemistry calculation. The results for the micro-flotation experiments showed that the addition of lizardite further decreased the floatability of talc at pH 8.5 when using CMC as the depressant. The mechanism was that magnesium ions dissolved from lizardite lattice, then formed hydrolyzed species of magnesium cations and interacted with talc surfaces, which promoted CMC adsorption, and thus decreasing talc floatability.

2

Dependence of thiamine pyrophosphokinase kinetics on the equilibrium concentration of magnesium complexes

100%

Kuczek M. , Strumilo S.

Cellular and Molecular Biology Letters

|

2002

|

tom 07

|

nr Suppl.

3

Effect of magnesium ions on the properties of channels formed by subunit c of F0F1-ATPase

86%

Saris N.-E. L. , Azarashvili T. S. , Odinokova I. V.

Journal of Elementology

|

2005

|

tom 10

|

nr 4 Suppl.1

92-93

4

Influences of magnesium ions in water on gelatinization characteristics of starch and its flocculation behaviors on particles

86%

Tang M. , Niu X. , Wen S.

Physicochemical Problems of Mineral Processing

|

2024

|

tom Vol. 60, iss. 1

art. no. 178149

EN

It is inevitable for the occurrence or built-ups of disturbing cations, especially Ca2+ or Mg2+ ions, in process water during the flotation of iron oxides by using starch as flocculants. In addition to alkali concentrations and temperature, water quality could have an essential role in changing the physicochemical properties of the starch solution and consequently disturbing its flocculation performance on particles. This study aims to identify the effects of magnesium ions on the gelatinization characteristics of starch and its flocculation properties on particles through a series of tests, such as flotation tests, settling tests, size analyses, zeta potentials, powder contact angle, Fourier Transform Infra-Red (FTIR) and X-ray Photoelectron Spectroscopy (XPS) measurement. All results show that magnesium ions at ≤ 4 mmol/L have a positive role due to enlarging the sizes of the particle flocs and accelerating their settling rates. The occurrence of Mg2+ ions at higher concentrations during starch gelatinization only obtains a starch sol-gel with entangled configurations and preoccupied active sites, resulting in the slower settling rate of the particle flocs and less hydrophilicity on mineral surfaces. It could be attributed to the cross-link interactions of magnesium-based precipitates with the acidic groups, especially carboxyl groups on the starch remnants. The suitable acid/base interactions between Mg(OH)2/MgCO3 compounds with these groups in the starch suspension could be beneficial for enhancing the flocculation of hematite as they could build bridges among the pieces and enlarge their sizes as a “load carrier” for aggregation with minerals. However, too much cross-linking could reentangle the remnants, block their adsorption sites on mineral surfaces, and eventually, weaken the flocculation capacity of starch.

5

Specificity and mechanism of the cleavages induced in yeast tRNAPhe by magnesium ions

86%

Marciniec T. , Ciesiolka J. , Wrzesinski J. , Wiewiorowski M. , Krzyzosiak W. J.

Acta Biochimica Polonica

|

1989

|

tom 36

|

nr 3-4

6

Selective precipitation of calcium ions by N,N-naphthaloylhydroxylamine - a cytochemical approach

86%

Sobota A. , Fabczak S. , Skoczylas B.

Acta Protozoologica

|

1988

|

tom 27

|

nr 2

7

Mg2plus ions do not induce expansion of the melted DNA region in the open complex formed by Escherichia coli RNA polymerase at a cognate synthetic Pa promoter. A quantitative KMnO4 footprinting study

86%

Lozinski T. , Wierzchowski K. L.

Acta Biochimica Polonica

|

2001

|

tom 48

|

nr 2

EN

Footprinting studies of prokaryotic open transcription complexes (RP O), based on oxidation of pyrimidine residues by KMnO4 and/or OsO4 at a single oxidant dose, have suggested that the extent of DNA melt ing in the tran scrip tion bub ble re gion increases in the presence of Mg2+. In this work, quantitative KMnO4 footprinting in func tion of the ox i dant dose of RPo, us ing EscherichiacoliRNA poly mer ase (Es7 ) at a fully func tional syn thetic pro moter Pa hav ing -35 and -10 con sen sus hexamers, has been used to de ter mine in di vid ual rate con stants of ox i da tion of T res i dues in this region at 37° C in the ab sence of Mg2+ and in the pres ence of 10 mM MgCl2, and to eval u- ate there from the ef fect of Mg on the ex tent of DNA melt ing. Pop u la tion dis tri butions of end-labeled DNA frag ments cor re spond ing to ox i dized Ts were quan ti fied and an a lyzed ac cord ing to the sin gle-hit ki netic model. Pseudo-first or der re ac tiv ity rate con stants, kx, thus ob tained dem on strated that Mg2+ ions bound to RPo merely enhanced the re ac tiv ity of all 11ox i diz able thymines be tween the +3 and -11 pro moter sites by a po si tion-dependent fac tor: 3-4 for those lo cated close to the tran scrip tion start point +1 in ei ther DNA strand, and about 1.6 for those lo cated more dis tantly there from. On the ba sis of these ob ser va tions, we con clude that Mg2+ ions bound to RPo at Pa do not in flu ence the length of the melted DNA re gion and pro pose that the higher re ac tiv ity of thymines re sults mainly from lower lo cal re pul sive elec tro static bar ri ers to MnO4- dif fu sion around carboxylate bind ing sites in the cat a lytic cen ter of RPo and pro moter DNA phos phates.

8

Mitochondrial adenosine triphosphatase from human placenta - inhibition by free magnesium ions of ITP hydrolysis

86%

Aleksandrowicz Z.

Acta Biochimica Polonica

|

1994

|

tom 41

|

nr 1

EN

The effects of Mg2+ and bicarbonate on the kinetics of ITP hydrolysis by soluble ATPase (Fi) from human placental mitochondria were studied. Increasing amounts of Mg2+ at fixed ITP concentration, caused a marked activation of Fi followed by inhibition at higher Mg2+ concentration. The appropriate substrate for the mitochondrial Fi seems to be the MglTP complex as almost no ITP was hydrolysed in the absence of magnesium. Mg2+ behaved as a competitive inhibitor towards the MglTP complex. In this respect the human placental enzyme differ from that from other sources such as yeast, beef liver or rat liver. The linearity of the plot presenting competitive inhibition by free Mg2+ of MglTP hydrolysis (in the presence of activating bicarbonate anion) suggests that both Mg2+ and MglTP bind to the same catalytic site (Km(MgITP) = 0.46 mM, Ki(Mg) = 4 mM). When bicarbonate was absent in the ITPase assay, placental Fi exhibited apparent negative cooperativity in the presence of 5 mM Mg2+, just as it did with MgATP as a substrate under similar conditions. Bicarbonate ions eliminated the negative cooperativity with respect to ITP (as the Hill coefficient of 0.46 was brought to approx. 1), and thus limited inhibition by free Mg2+. The results presented suggest that the concentration of free magnesium ions may be an important regulatory factor of the human placental Fi activity.

9

Molecular modelling of selected magnesium organic salts. Structure - activity relationship

72%

Marcoin W.

Journal of Elementology

|

2006

|

tom 11

|

nr 1

EN

Contemporary medical and biochemical research shows that Mg complex with organic ligands seem to be of great interest to researches. The study was undertaken in order to look for new drugs, which could meet the needs and expectations of clinical doctors. The selected QSAR parameters describing the geometrical structure of magnesium salts were compared with the log P values in order to estimate bioavailability of magnesium from these compounds. Intramolecular reactions e.g. donor-acceptor and occurence of hydrogen bonding influencing values of the calculated surface area of molecules to their volume and changes of log P value and polarity were confirmed.

PL

Współczesne badania medyczne i biochemiczne wykazały, że kompleksy Mg2+ z ligandami organicznymi wydają się interesujące. Poszukiwania coraz to nowych leków, które spełniłyby oczekiwania klinicystów, były inspiracją podjętych badań. Obliczono wybrane parametry QSAR opisujące geometryczną strukturę soli magnezowych i porównano je z wartością log P, aby móc ocenić biodostępność jonów magnezowych z tych związków. Potwierdzono oddziaływania wewnątrzcząsteczkowe typu donor-akceptor i wiązania wodorowe, mające wpływ na obliczone wartości powierzchni cząsteczek, ich objętości oraz zmiany wartości log P i polaryzowalności.

10

Effect of Mg2plus on kinetics of oxidation of pyrimidines in duplex DNA by potassium permanganate

72%

Lozinski T. , Wierzchowski K. L.

Acta Biochimica Polonica

|

2001

|

tom 48

|

nr 2

EN

Po tas sium per manga nate ox i da tion of py rim i dine bases is of ten used to probe single-stranded re gions in func tional DNA-pro tein com plexes. How ever, so far re ac tiv- ity of these bases in double-stranded DNA has not been studied quantitatively. We have investigated the kinetics of oxidation of pyrimidines in supercoiled pDS3 plasmid dsDNA by quan ti ta tive KMnO4 footprinting, in con nec tion with par al lel stud ies on the ef fect of Mg2+ on ki net ics of ox i da tion of in di vid ual thymines in the single-stranded re gion of the open tran scrip tion com plex of Escherichiacoli RNA polymer ase at a cog nate Pa pro moter con tained in this plasmid. Rate con stants of ox i dation for pyrimidines, kj, in selected regions of pDS3 DNA, including Pa promoter, were de ter mined un der sin gle-hit re ac tion con di tions in the ab sence and pres ence of 10 mM MgCl2. Their val ues ap peared to be se quence-dependent and were: (i) the largest for Ts in 5 TA3' and 5 TC3' steps, while 2-4 times smaller for 5'-adja cent ones in TT(A,G,C) and TTT(A) runs, (ii) for Cs in 5'TC3' steps 2-4 fold smaller than for ad ja- cent Ts, and (iii) in the pres ence of Mg2+ gen er ally larger by a se quence-dependent factor: in 5' TC3' steps of about 2 and 4 for Ts and Cs, re spec tively, in 5 TA3' steps of TTA and TTTA se quences for 3 -ter mi nal Ts of about 3, while for their 5 -neigh bors of a distinctly smaller value of about 2. Com par i son of kj data for cor re spond ing Ts lo cated be tween +1 and -10 re gions of Pa pro moter in dsDNA and in ssDNA form in the open transcription complex, reported elsewhere, demonstrates that reactivity of pyrimidines in dsDNA is by 2-3 or ders of mag ni tude smaller. The ef fect of Mg 2+ in dsDNA is in ter preted in terms of elec tro static bar rier to dif fu sion of MnO4- on DNA surface, which is low ered by dif fu sive bind ing of these ions to back bone phos phates, in volv ing also se quence-specific con tacts with bases in the mi nor and major grooves of B-DNA.

11

Proteoliposomes vs. thylakoids

58%

Gieczewska K. , Mazur R. , Grzyb J. , Mostowska A.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

|

2013

|

tom 94

|

nr 3

12

Effect of magnesium on beneficial organisms

58%

Jaworska M. , Gospodarek J.

Journal of Elementology

|

2009

|

tom 14

|

nr 2

257-263

EN

The paper presents the results of research on magnesium effect on beneficial enthomopathogenic fungi and nematodes as well as some predatory arthropods. Magnesium fertilization of soil contaminated with heavy metals does not significantly affect numbers of the majority of epigeal invertebrates, but it may influence numbers of single species, favouring the occurrence of some (Bembidion sp.) while restricting the presence of others (Harpalus rufipes De Geer). Magnesium synergism with heavy metal ions has been found to increase infectiveness and pathogenicity of enthomopathogenic fungi. Magnesium, in a dose of 160 mg⋅dm-3 present in the medium, significantly enhances pathogenicity of fungi, such as Beauveria bassiana, Paecilomyces farinosus, Paecilomyces fumoso-roseus or Metarhizium ansopliae. Increased pathogenicity of Steinernema carpocapsae and Heterorhabditis bacteriophora towards test insects has also been observed when magnesium ions were added to a solution in which these nematodes were kept. An effective magnesium dose differed depending whether the nematodes were used separately for test insects (450 mg⋅dm-3) or jointly with enthomopathogenic fungi (320 mg⋅dm-3). This protective effect of magnesium ions on beneficial microorganisms has also been observed in soil contaminated with heavy metals. An addition of magnesium to a solution in which enthomopathogenic nematodes were kept (160 mg⋅dm-3) and to a medium on which fungi were cultured (320 mg⋅dm-3) increased pathogenic abilities of these organisms in contaminated soil to a very high degree (10- to 300- fold higher than the natural heavy metal content in soil).

PL

W pracy zestawiono wyniki badań nad wpływem magnezu na pożyteczne grzyby i nicienie owadobójcze oraz wybrane stawonogi drapieżne. Nawożenie magnezowe gleby skażonej metalami ciężkimi nie wpływa istotnie na liczebność większości grup bezkręgowców naziemnych, może jednak wpływać na liczebność pojedynczych gatunków, sprzyjając występowaniu jednych (Bembidion sp.), a ograniczając występowanie innych (Harpalus rufipes De Geer). Stwierdzono synergizm magnezu z jonami metali ciężkich w podnoszeniu infekcyjności i patogenicznści grzybów owadobójczych. Magnez obecny w pożywce, w dawce 160 g.dm-3, istotnie podwyższał patogeniczność takich grzybów, jak: Beauveria bassiana, Paecilomyces farinosus, Paecilomyces fumoso-roseus, Metarhizium ansopliae. Zaobserwowano również zwiększenie patogeniczności nicieni owadobójczych Steinernema carpocapsae i Heterorhabditis bacteriophora wobec owadów testowych po dodaniu jonów magnezu do roztworu, w którym przechowywano te nicienie. Efektywna dawka magnezu była zróżnicowana, zależnie od tego, czy nicienie stosowano samodzielnie wobec owadów testowych (450 mg.dm-3), czy te¿ wraz z grzybami owadobójczymi (320 mg.dm-3). Obserwowano także protekcyjny wpływ jonów magnezu na pożyteczne mikroorganizmy w warunkach gleby zanieczyszczonej metalami ciężkimi. Dodanie magnezu do roztworu, w którym przechowywano nicienie owadobójcze (160 mg-.dm-3), i do pożywki, na której hodowano grzyby (320 mg.dm-3), zwiększało zdolności patogeniczne tych organizmów w warunkach gleby skażonej metalami ciężkimi nawet w bardzo wysokim stopniu (10-300-krotnie wyższa zawartość metali ciężkich w glebie ponad zwartość naturalną).

13

An elastase-like endopeptidase in the penetration glands of the cercariae of Neoglyphe sobolevi [Digenea, Plagiorchiidae]

58%

Moczon T.

Acta Parasitologica

|

1997

|

tom 42

|

nr 2

EN

An elastase-like proteinase was localized histochemically in the penetration glands of the cercariae of Neoglyphe sobolevi. The enzyme extracted from the larvae hydrolyzed azocoll, gelatin, azoalbumin, azocasein, and elastin-orcein at optimal pH of 8.4, 8.4, 8.0, 7.6, and 8.4, respectively. The nonionic detergent Triton X-100 slightly enhanced its activity toward azocoll, whereas the anionic detergent SDS, and the cationic detergent cetyltrimethylammonium bromide acted as strong inhibitors. Magnesium ions stabilized the proteinase activity. Strong calcium and magnesium chelators (EGTA, EDTA) and the serine proteinase inhibitor DFP (0.1 mM) inhibited it. 2 mM 1,10-phenanthroline, a relatively specific chelator of zinc, produced a weak inhibition. The results indicate, therefore, that the active proteinase represents a metal-enzyme complex rather than a metalloenzyme. Being capable of hydrolyzing N-blocked L-alanine-1-naphthylester, N-blocked L-methionine-1-naphthylester, and naphthyl AS-D chloroacetate at pH 6.8, the proteinase activity was insensitive to 1 mM p-nitrophenyl phosphate, an inhibitor of some mammalian esterproteinases. The enzyme did not split N-blocked-DL-phenylalanine-2-naphthylester and also N-blocked L-aminoacyl- and N-blocked L-peptidyl-naphthylamides bearing L-arginine, L-alanine, L-phenylalanine, L-leucine, or L-proline at the P₁ subsite. At operative pH values of 4.8 and 3.5 generated during electrophoresis in a stacking and a resolving gel, respectively, the cercarial proteinase migrated toward the cathode. The separated enzyme produced four bands of proteolysis in a gelatin-containing polyacrylamide gel, at the optimal pH of 8.4.

14

Acidification and chemistry of stream water on the example of the Waksmundzki and Mietusi Streams in the Tatra Mountains, [Southern Poland]

58%

Grodzinska-Jurczak M.

Acta Hydrobiologica

|

1996

|

tom 38

|

nr 1-2

EN

A three-year study (1991-1993) on the chemistry of streams was carried out in two valleys of different bedrock in the Polish Tatra Mountains. Significant seasonal fluctuations in the concentration of most of the studied elements of the granitic Waksmundzki and carbonate Miętusi Streams were observed. The chemistry of the Miętusi Stream was dominated by calcium and magnesium ions and the Waksmundzki Stream by sulphate ions. The drawing of general conclusions on changes in the stream chemistry over the last 30 years is impossible because of the different analytical methods used and only a single samplings of the stream water taken by the investigation carried out in the 60’s.

PL

Przeprowadzono 3-letnie (1991-1993) badania hydrochemiczne w dwóch dolinach różniących się typem podłoża geologicznego. W granitowym Potoku Waksmundzkim i wapiennym Potoku Miętusim stwierdzono istotne zmiany sezonowe w stężeniu większości badanych pierwiastków. Chemizm wody Potoku Miętusiego był zdominowany przez jony wapniowe i magnezowe, a Potoku Waksmundzkiego przez jony siarczanowe. Wyciągnięcie ogólnych wniosków na temat zmian hydrochemicznych w ciągu ostatnich 30 lat nie jest możliwe, ponieważ badania przeprowadzone w latach 60-tych były wykonane innymi metodami i zostały oparte na pojedynczych próbach.

15

Wplyw blanszowania na jakosc frytek ziemniaczanych

51%

Tajner-Czopek A. , Lisinska G.

Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin

|

2004

|

nr 232

285-294

16

Wplyw skladnikow suplementow diety - wapnia i magnezu na lepkosc fibryny nieusieciowanej

44%

Michalska M. , Kolodziejska J.

Bromatologia i Chemia Toksykologiczna

|

2006

|

tom 39

|

nr 2

173-178

17

Ciężkie zaczyny cementowo- lateksowe odporne na działanie solanek magnezowych o różnej mineralizacji

44%

Kątna Z.

Cement Wapno Beton

|

2008

|

tom R. 13/75, nr 4

196-204

PL

Przedstawiono wyniki badań stwardniałych zaczynów cementowych sporządzonych z ciężkich zawiesin cementowo-lateksowych, w których jako materiał wiążący zastosowano cement hutniczy CEM III/A 32,5 oraz mieszaniny cementów hutniczego i wiertniczego typu WG i G. Próbki stwardniałych zaczynów cementowych przez okres 28 dni poddawano działaniu wód złożowych z dużą zawartością jonów magnezu. Opracowano składy zawiesin cementowych dających stwardniałe zaczyny o znikomej przepuszczalności dla gazów oraz o dużej wytrzymałości na ściskanie, odporne na działanie solanek o dużej zawartości związków magnezowych.

EN

Hardened heavy-weight cement grouts with latex addition, based on the metallurgical cement CEM Ill/A 32,5 and oil well cement type WG and G were examined. The samples were stored at temperature 95°C in the magnesium-rich deposit waters and laboratory made brine. Cement grouts produced from 50% metallurgical cement CEM Ill/A and 50% oil well cement, cured in magnesium brines of lower concentration <20 Mg2+ ions/I at temperature 95°C, reveal high compressive strength. These grouts can be applied as resistant, low-permeable pipe sealing agent in oil wells cementing.

18

Calcium effect on mitotic activity and frequency of mitotic disturbances in the cortex cells of Pisum sativum L. roots treated with heavy metals

44%

Gabara B. , Golaszewska E.

Bulletin of the Polish Academy of Sciences. Biological Sciences

|

1992

|

tom 40

|

nr 2

19

Wplyw weglanu wapnia, gipsu i fosfogipsu na plony oraz sklad chemiczny roslin i roztworu glebowego

36%

Sosulski T. , Szara E. , Labetowicz J.

Zeszyty Problemowe Postępów Nauk Rolniczych

|

2008

|

tom 533

345-355

PL

W doświadczeniu wazonowym przebadano wpływ węglanu wapnia, gipsu i fosfogipsu na plon i skład chemiczny roślin oraz pH i zawartość Ca²⁺, Mg²⁺, K⁺ w roztworze glebowym. Do badań została użyta gleba lekka, pochodząca z warstwy ornej niewapnowanego obiektu NPK, trwałego doświadczenia nawozowego prowadzonego w Wydziałowej Stacji Doświadczalnej SGGW w Skierniewicach. Roślinami testowymi były: gorczyca biała (Sinapis alba L.) oraz koniczyna czerwona (Trifolium pratense L.). Dawki wapnia w użytych substancjach wyliczono na podstawie 1,2 i 4 Hh. Największy przyrost plonów uzyskano stosując CaCO₃, natomiast użyte do nawożenia odpady na ogół zmniejszały plony uprawianych roślin. Węglan wapnia powodował wzrost zawartości Ca i Mg i spadek zawartości K w roślinach. Pobranie Ca, Mg i K przez rośliny było największe na obiektach z węglanem wapnia, mniejsze na obiektach z gipsem i najmniejsze na obiektach z fosfogipsem. Zastosowanie największych dawek odpadów było przyczyną zaburzenia gospodarki jonowej roślin w wyniku, którego dochodziło do rozszerzenia stosunku K : (Ca + Mg). Dominującym jonem roztworu glebowego gleby silnie kwaśnej był potas, deficytowym zaś magnez. Wapnowanie zwiększyło zawartość wapnia, a zmniejszyło zawartość magnezu w roztworze glebowym po zbiorze roślin. Na obiektach z gipsem i fosfogipsem zawartość wszystkich badanych jonów była wielokrotnie większa niż na obiektach wapnowanych (CaCO₃), a dominującym jonem był kation wapnia.

EN

The influence of calcium carbonate and waste material: gypsum and phos- phogypsum on yields and chemical composition of plants, pH and the content of Ca²⁺, Mg²⁺, K⁺ in the soil solution in a pot experiment was investigated. The soil was taken from the plough layer of non limed NPK object of long-term experiment carried out at the Experimental Station in Skierniewice belonging to Warsaw University of Life Science. Calcium rates in different on the basis of substances were calculated 1, 2 and 4 soil hydrolytic acidity. White mustard (Sinapis alba L.) and red clover (Trifolium pratense L.) were the test plants. Higher crops were obtained using CaCO₃ . The wastes mostly caused the crop decrease. Calcium carbonate caused the increase of Ca and Mg content and decrease of K content in the plants. Ca, Mg and K uptake by plants was the highest on the object with CaCO₃, lower on gypsum and the lowest on the phosphogypsum object. The use of the highest rates of waste material disturbed the plant ion managment and widened the ratio K : (Ca + Mg). Potassium was a dominating ion in the soil solution of the strongly acid soil which was least in magnesium. Liming increased the content of calcium and made the content of magnesium and potassium in soil solution lower after the harvest of plants. On the objects with gypsum and phosphogypsum the content of all the examined ions was higher than on objects repeatedly limed, and calcium was a dominatingion.

20

Jakosc wod powierzchniowych w gorskich mikrozlewniach rolniczo-lesnych

29%

Kanownik W. , Pijanowski Z.

Acta Scientiarum Polonorum. Formatio Circumiectus

|

2002

|

tom 01

|

nr 1-2

61-70