Search

The calcium phosphate tungsten bronze (Ca-PWB) has been synthesized and characterized (TGA, DSC, XRPD, FTIR, SEM). The influence of solid insoluble materials Ca-PWB, as well as lithium doped (Li-PWB) and cation free phosphate tungsten (PWB) bronzes on the oscillatory Briggs-Rauscher (BR) reaction dynamics, is compared. The results show that doping with Li and Ca reduces sensitivity of the BR reaction towards bronzes addition. These findings suggest the usage of the BR reaction as an innovative method for testing of different properties of bronze material. The behavior of PWB in the BR reaction is significantly changed with divalent cation (Ca2+) doping. The reasons for the different bronzes behavior were found in their calculated unit cell volumes. Namely, the compressed Ca-PWB unit cell volume indicates the difficult availability of the active site for heterogeneous catalysis. Hence, the linear correlation (slope) of the BR oscillogram’s length (τosc) vs. mass of bronze in BR reaction might be considered as a new parameter for the evaluation of the bronzes catalytic activity., У овом раду синтетисана је и окарактерисана (TGA, DSC, XRPD, FTIR, SEM) нова калцијумом допирана фосфат волфрамова бронза (Ca-PWB). Испитан је и упоређен утицај фосфат волфрамове бронзе (PWB), литијумом допиране фосфат волфрамове бронзе (Li-PWB) и калцијумом допиране фосфат волфрамове бронзе (Ca-PWB) на осцилаторну динамику Briggs-Rauscher (БР) реакције. Резултати показују да допирање катјонима Li+ и Ca2+ смањује осетљивост БР реакције на додатак нерастворних бронзи, што се огледа у смањивању нагиба праве осцилаторног времена (τosc) БР реакције у функцији масе додате допиране бронзе. Добијени резултати сугеришу употребу БР реакције као иновативне методе за испитивање различитих својстава допираних и недопиране фосфат волфрамове бронзе. Разлози за различито понашање бронзи у осцилаторној реакцији пронађени су у различитим величинама јединичних ћелија PWB, Li-PWB и Ca-PWB. Наиме, најмања вредност, тј. сабијање јединичне ћелије допирањем калицијумом указује на тежу доступност активних места за хетерогену катализу. Каталитичка активност бронзи усмерена је ка реакцијама оксидације које укључују водоник-пероксид (један од реактаната БР реакције). Стога би се линеарна корелација (нагиб) τosc у функцији масе бронзе у БР реакцији могла сматрати новим параметром за процену каталитичке активности бронзе, али и других материјала.

Chlorpyrifos (CPS) is a toxic pesticide present in several pesticide formulations, with low degradability by natural processes. The degradation leads to the toxic metabolite chlorpyrifos-oxon (CPO). The analytical techniques used for the CPS and CPO analysis, like UPLC-PDA and GC-MS, are accurate but also expensive and time consuming, and they need sample pretreatment. In the search of a more rapid and simple analytical procedure, atmospheric solids analysis probe with mass spectrometry (ASAP-MS) was optimized for the determination of CPS and CPO in apples (Malus domestica „Idared”). The identification of the analytes was based on protonated ion and isotopic pattern, while the quantification was based on peak intensities. The obtained results were confirmed by re-validated UPLC-PDA and GC-MS techniques. CPS and CPO concentrations determined by ASAP-MS and UPLC-PDA showed moderate discrepancies (on average by 10–20%), thus demonstrating that ASAP-MS can be a semiquantitative tool for the quantification of these compounds. As additional goal of this work, the efficiency of a gamma irradiation treatment to remove CPS and CPO from apples was tested by analyzing their content before and after the irradiation: 89–99% of CPS and CPO were degraded with doses of 3.5–3.8 kGy and 66–72 h of irradiation per sample. Identical degradation results were obtained by UPLC-PDA and ASAP-MS, indicating that the latter technique is well suitable to rapidly check pesticide degradation in apples. © 2019 Slovensko Kemijsko Drustvo. All Rights Reserved.

Hybrid compounds that combine the 1,3,4-thiadiazole-containing catechol moiety with a chalcone motif were synthesized and examined for their antioxidant activity, cytotoxicity, and DNA-binding activity. A series of thirteen compounds showed strong antioxidant and cytotoxic effects on human acute promyelocytic leukemia HL-60 cells. Several compounds exerted good cytotoxic activities on cervical adenocarcinoma HeLa cells. The treatment of HeLa cells with IC50 and double IC50 concentrations of the compounds 5a, 5c, 5f, and 5m induced a statistically significant increase in the percentage of cells within a subG1 cell cycle phase. The examined compounds caused G2/M cell cycle arrest in HeLa cells. Each of these compounds triggered apoptosis in HeLa cells through activation of caspase-3, the main effector caspase, caspase-8, which is involved in the extrinsic apoptotic pathway, and caspase-9, which is involved in the intrinsic apoptotic pathway. All of the examined compounds decreased the expression levels of MMP2 in HeLa cells and levels of protumorigenic miR-133b. Compounds 5a and 5m lowered the expression level of oncogenic miR-21 in HeLa cells. In addition, compounds 5a, 5f, and 5m decreased the expression levels of oncogenic miR-155 while the treatment of HeLa cells with compounds 5a, 5c, and 5f increased expression of tumor-suppressive miR-206. Observed effects of these compounds on expression levels of four examined miRNAs suggest their prominent cancer-suppressive activity. An investigation by absorption and fluorescence spectroscopy showed more efficient calf thymus DNA binding activity of the compound 5m in comparison to other tested compounds. Results of a pUC19 plasmid cleavage study and comet assay showed DNA damaging activities of compounds 5a and 5c.

Radiofarmaceutici bazirani na različitim molekulima obeleženimitrijumom-90, se koriste pri tretmanu neoperativnih vrsta tumora, kao i u radijacionoj sinovektomiji. Veliko interesovanje za korišćenje 90Y u terapeutske svrhe potiče zbog njegovih nuklearnih karakteristika (t1/2=64,1, Eβ,max= 2,3 MeV,bez emisije  zračenja). Dostupnost 90Y sa vrlo niskom radiohemijskom kontaminacijom je od suštinske važnosti u terapeutskoj primeni.Postojanje dugoživućeg pretka 90Sr sa vremenom poluživota od 28,9 godina i kratkoživućeg potomka 90Y nam omogućavaju formiranje generatorskog sistema. Iako postoje nekoliko vrsta generatora, prema literaturnim podacima, elektrohemijski generatori i generatori zasnovani na tečnim membranama imaju najveću perspektivu.Membranska ekstrakcija se takođe naziva i pertrakcija i bazirana je natrofaznom sistemu sa organskom fazom (tečna membrana) koja se nalazi između dve vodene faze i predstavlja alternativnu metodu klasičnoj tečno-tečnoj ekstrakciji. Prema literaturnim podacima, koristi se za razdvajanje širokog opsega rastvorenih supstanci uključujući biološke molekule, metalne jone, organske zagađivače i radionuklide.Elektrohemijska metoda je predložena kao rešenje pri separaciji 86Y od 86Sr i dobijanje 86Y koji služi pri pozitronsko emisionoj tomografiji (PET).Literaturni podaci pokazuju da elektrohemijska separacija predstavlja dobro rešenje jer omogućava veliku efikasnost uz minimalnu kontaminaciju okolnog prostora.Radiofarmaceutici koji se koriste u terapiji su u hemijskom smislukompleksna jedinjenja u kojima se kao centralni joni javljaju radioaktivni izotopi metala sa  ili  raspadom, dok su ligandi organski molekuli koji su sposobni da stvaraju helate. Ovi molekuli pored toga što su helatori za radiometal imaju i ulogu da se vežu za biomolekul. Zbog toga se i nazivaju bifunkcionalni helatori. Najpoznatiji i do sada najviše korišćeni bifunkcionalni helatori u radiohemiji itrijuma su: 1,4,7,10-tetraazociklododekan-1,4,7,10-tetraacetatna kiseli, The subject of this dissertation was biospeciation of Y(III) ion in human blood plasma. To this end characterization of complexation equilibria of Y3+ with DTPA, DOTA and ciprofloxacine and production of yttrium-90 from Sr/Y generator was made.Hydrolysis and complexation of yttrium were investigated using potentiometricmesurenment with glass electrode in 0.15 mol dm-3 NaCl ionic medium, at 310.0 ± 0.5 К. In addition, data of the hydrolysis of yttrium (III) ion and complexation of yttrium (III) ion with DTPA and DOTA were obtained by ESI MS technique. Morphologies of various kinds of yttrium-hydroxide precipitates were examined using a scanning electron microscopy. Precipitates were also analyzed by thermogravimetric analysis (TGA) and infrared spectroscopy using KBr pill technique. Computer modeling May model was used for the determination of yttrium species in human plasma and certain dominant yttrium complexes with small molecules. The second part of the Thesis relate to the separation of90Y from 90Sr with high radiochemical yield and purity, that can be used for labelling organic molecules (DTPA and DOTA) which are used in nuclear medicine.The obtained results can be sumarized as follows: The stability constants of hydrolitic complexes (log β,.q) were: Y(OH)2+ (log β1,-1 = -7.71 ± 0.05), Y(OH)2+ (log β1,-2 = -16.42 ± 0.03), Y(OH)3 (log β1,-3 = -26.01± 0.03),Y2(OH)2 4+(log β2,-2 = -14.23± 0.05), Y3(OH)54+ (log β3,-5 = -34.20 ± 0.07) иY4(OH)66+(log β4,-6 = -37.10 ± 0.08). Hydrolytic species determined by potentiometric method were confirmed by ESIMS method also. Hydrolytic species containing tetramer ions with high charges were: [Y4(OH)4(H2O)2]8+, [Y4(OH)2Cl2]8+ и [Y4(OH)3ClH2O]8+. The hydrolytic precipitation reactions with NaOH or urea as precipitating agents were studied. The obtained precipitates were characterized by the X-ray diffraction, the SEM technique, thermal analysis (TG-DSC) and infrared spectroscopy. Powder X-ray diffraction (XRD) characterization

Hydrolysis reactions of YCl3 aqueous solutions were studied by potentiometric titrations at 310 K in the pH range ca.3-9 and total Y3+ ion concentration range 0.5-10.0 mmol/dm(3). The experimental data were evaluated with the aid of the Hyperquad2006 suite of programs, which indicated the formation of the following hydrolytic complexes (log conc. overall stability constants beta(p,q) defined as beta(p,q) = M-p(OH)(q)[H](q)/[M](p)), Y(OH)(2+) (-7.71(2)); Y(OH)(2)(+) (-16.42(2)); Y(OH)(3) (-26.01(3)); Y-2(OH)(2)(4+) (-14.23(4)); Y-3(OH)(5)(2+) (-34.20 (4)); Y-4(OH)(6)(2+) (-37.10(5)). The hydrolysis of the Y3+ ion was also monitored by electrospray ionization ion-trap mass spectrometry (ESI-MS) in the pH range 2.63-7.10. The influence of the sample cone voltage on the product distribution was significant, indicating the contribution of ion source fragmentation reactions. The optimal cone voltage was set to 70 V for cationic and 100 V for anionic spectra. The cationic and anionic ESI mass spectra of the Y3+ solutions produced strong evidence for the presence of a variety of monomeric and polymeric hydrolytic complexes. The Cl- ion appeared to be a strong competitor to the OH- ion for the oxo-yttrium core. The hydrolytic precipitation reactions with NaOH or urea as precipitating agents were studied. The obtained precipitates were characterized by the potentiometric technique, elemental analysis, thermal analysis (TG-DSC), infrared spectroscopy, X-ray diffractions and the SEM technique. Hydrothermal synthesis of the precipitate in an autoclave at T= 420 K and P = 10 bar with NaOH as the precipitating agent produced a crystalline precipitate in the form of hexagonal needles (P6(3)/m space group). At atmospheric pressure only an amorphous precipitate was produced with both precipitating agents. The concentration solubility product K-so* of Y(OH)(3) was evaluated from the potentiometric titrations curves and logK(so)* = -22.85(4). The synthesized precipitate with NaOH as a

Complex formation equilibria of aluminum(III), gadolinium(III), and yttrium(III) ions with the fluoroquinolone antibacterials moxifloxacin, ofloxacin, fleroxacin, lomefloxacin, levofloxacin, and ciprofloxacin were studied in aqueous solution by potentiometric and spectroscopic methods. The identity and stability of metal-fluoroquinolone complexes were determined by analyzing potentiometric titration curves (310K, =0.15M NaCl, pH range=2-11, C-L/C-M=1:1 to 3:1, C-M=1.0mM) with the aid of Hyperquad2006 program. The main species formed in the system may be formulated as MpHqLr (p=1, q=-2 to 2, r=1-3, L=fluoroquinolone anion, logarithm of overall stability constant, log (p,q,r)=in the range ca. -10 to 45). The stability of complexes is mostly influenced by metal ion properties (ionization potential, ionic radius) indicating partial ionic character of the coordination bond. The complexes were also characterized by spectroscopic measurements: spectrofluorimetry, H-1-NMR, and ESI-MS. Fluorimetric data were evaluated with the aid of HypSpec2014 and indicated the formation of MLr (r=1-3) complexes with cumulative conditional stability constants significantly lower than the thermodynamic ones. NMR and MS data corroborate potentiometrically determined speciation. Calculated plasma mobilizing capacity of the ligands generally follows the order levofloxacin GT moxifloxacin GT ciprofloxacin at concentration levels of the ligands higher or equal to ca. 10(-4)M.

The speciation of Al3+, Gd3+ and Y3+ ions in human plasma has been studied by computer simulation using the program HySS2009. A literature computer model of blood plasma was updated and comprised 9 metals, 43 ligands and over 6100 complexes. To this model critically evaluated data of Al3+, Gd3+ and Y3+ constants with blood plasma ligands have been added. Low molecular mass (LMM) speciation of Al3+ ion strongly depends upon the chosen equilibrium model of the metal - phosphate and metal - citrate systems. The obtained computer simulation of LMM speciation data of Al3+ ion were: AlPO(4)Cit (40.7%), AlPO(4)CitOH (22.9%), AlCitOH (19.2%) and AlPO4(OH) (12.7%) (% of total LMM Al species pool); for Gd3+ ion: GdAspCit (30%) and GdCit(OH)(2) (20%) (% of total [Gd]) and for Y3+ ion: YCit (48%), Y(CO3)(2) (32%) and Y(CO3) (11%) (% of total [Y]). Citrate appears as the important binding and mobilizing ligand for all examined ions, while the dominating species are the ternary ones.

New polymeric copper(II) complexes with two tridentate ONS thiosemicarbazone ligands containing substituted pyrazolone moiety were synthesized and characterized by means of spectroscopic, electrochemical and crystallographic techniques. While both ligands exist as different tautomers in the solid state and DMSO-d(6) solution, Cu(II) ion coordinates the ligands from the same tautomeric form with square-pyramidal geometry around each Cu atom. In the crystal structures, the copper(II) complex cation forms polymeric chains {[Cu(L)Cl(+)]}(n) with a bridging chlorine atom. One of the complexes was found to have a significantly higher cytotoxic potential in comparison with cisplatin in inhibition of several cell lines (HL60, REH, C6, L929 and B16). The results obtained on the basis of flow cytometry indicated that apoptosis could be possible mechanism of cell death. (C) 2011 Elsevier Inc. All rights reserved.