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1
Content available Dekontaminacja chemiczna systemów pierwotnego obiegu chłodzącego w elektrowniach jądrowych
Łyczko M., Filipowicz B., Bilewicz A., Łyczko K.
Postępy Techniki Jądrowej
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2014
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z. 2
10--15
2
Content available Nieorganiczne nanocząstki w medycynie nuklearnej
Kasperek A., Bilewicz A.
Wiadomości Chemiczne
|
2012
|
[Z] 66, 7-8
697-714
EN
Rapid and widespread growth in the use of nuclear medicine for both diagnosis and therapy of disease has been the driving force for a design of novel radiopharmaceuticals. Particularly, recent progress in nanotechnology gives the possibility of designing new carriers for delivering radionuclides in a manner to overcome some limitation such as nonspecific biodistribution and targeting, water insolubility, poor oral bioavailability and others. There are several perspective therapeutic and diagnostic radionuclides which cannot be bound to biomolecule via chemical bonds. Nanocarriers gives the opportunity for binding such radionuclides. Nanoparticles have to be designed with an optimal size (above 100 nm) and surface characteristic to easily penetrate the barriers in the body and prevent elimination by reticuloendothelial system. Among nanoparticles which are used for delivery and targeting are polymers, lipids, viruses, organometallic compounds, precious metals or metal oxides. This article presents a brief review of the applications, advantages, difficulties and future perspective of inorganic nanoparticles, which can be used as radionuclide delivery systems. The main direction of developing new nanostructures for nuclear medicine is to create multimodal agents which are suitable for such combined methods as PET /MRI or PET /NIRF. Also combination of diagnostic and therapeutic agents in one nanocontainer is possible.
3
Content available Badania chemiczne w Instytucie Chemii i Techniki Jądrowej nad projektowaniem i syntezą nowych radiofarmaceutyków
Bilewicz A., Fuks L., Gniazdowska E., Kasperek A., Koźmiński P., Krajewski S., Leszczuk E., Łyczko M.
Postępy Techniki Jądrowej
|
2012
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z. 2
2--13
4
Content available remote Makrocykliczne kompleksy radionuklidów w medycynie nuklearnej
Majkowska A., Bilewicz A.
Wiadomości Chemiczne
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2008
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[Z] 62, 7-8
609-633
EN
The use of radiometal-labeled small complexes and biomolecules as diagnostic and therapeutic agents is a relatively new area of medical research. Radiopharmaceuticals are radiolabeled molecules designed to deliver ionizing radiation doses to specific disease sites. Between the targeting biomolecule and a radionuclide a bifunctional ligand is inserted, one end of which is covalently attached to the targeting molecule either directly or through a linker whereas the other strongly coordinates a metallic radionuclide. Selection of a bifunctional ligand is largely determined by the nature and oxidation state of a metal ion. The metal chelate can significantly affect the tumor uptake and biodistribution of radiopharmaceuticals based on small biomolecules. This is because in many cases the metal chelate contributes greatly to the overall size and lipophilicity of the radiopharmaceutical. Therefore, the design and selection of the ligand is very important for the development of a clinically useful therapeutic agent. The requirement for high thermodynamic and kinetic stability of the metal complex is often achieved through the use of macrocyclic ligands with a functionalized arm for covalent bonding to the biomolecule. In this review synthesis of bifunctional macrocyclic ligands and properties of radionuclide macrocyclic complexes used in nuclear medicine are presented. We describe results in two areas: substituted macrocyclic aza ligands for chelation of hard metal cations, and macrocycles containing sulphur for complexation of soft metal cations. Special attention was paid to stability of the complexes as well as to their lipophilicity, which affect biological properties of the formed radiopharmaceuticals. We also include a forecast of the near-term opportunities that are likely to determine practice in the next few years.
5
Content available remote Astat w chemii i medycynie
Pruszyński M., Bilewicz A.
Wiadomości Chemiczne
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2004
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[Z] 58, 5-6
403--425
EN
Astatine, element 85, is the heaviest halogen. The first synthesis of' 211At was performed by Corson by irradiation of 209Bi target with a-particles. Most of the chemical studies have been done using this isotope. Astatine is one of the most difficult clements to study from a chemical point of view, and our knowledge of its compounds is rather incomplete compared to what we know about other elements. For this there are several reasons, especially that the astatine have very short-lived isotopes which make it impractical to obtain weighable amounts of the element. Therefore, chemical studies of astatine can be performed only with very low concentrations - concentrations much less than the impurity levels commonly present in an experimental system. Radionuclide 211At has been newly discovered within development of nuclear medicine, because it has a lot of diserable and advantageous properties, that are required in cancer therapy. It's potential application was recognized due to the radiotoxicity associated with emission of a particle and that of its daughter 211Po. This review presents current knowledge about chemistry of astatine, especially its inorganic chemistry (e.g. valence states, anionic complexes of astatine with halogenides and pseudohalogenides ions etc.). Moreover, information is given about synthesis of some organic compounds of astatine. Special attention was paid on labelling of biologically active molecules with 211At and their potential applications in nuclear medicine.
6
Content available Sorption properties of stainless steel membranes impregnated with titanium dioxide sorbent
Bilewicz A.
Nukleonika
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2004
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Vol. 49, nr 4
163-165
EN
High-temperature sorption of corrosion products from primary cooling circuit is an effective method for radiation reduction in pressurize and boiling reactor plants. We have developed a suitable high temperature resistant adsorbent by impregnating a porous stainless steel membrane with titanium oxide. The adsorption studies of corrosion products in soluble and insoluble forms indicate that the stainless steel membrane impregnated with TiO2 combines high affinity of TiO2 for transition metal cations with a high mechanical stability of the porous steel membrane under high-temperature and highpressure conditions.
7
Content available remote Simultaneous determination of 224Ra and 226Ra isotopes by measuring of emanated 220Rn and 222Rn using a 4-inch silicon epitaxial detector
Kordyasz A. J., Bartoś B., Bilewicz A.
Chemia Analityczna
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2004
|
Vol. 49, No. 1
29-39
EN
Fast method for simultaneous determination of 224,226Ra and estimation of 228Ra content in water samples by the measurement of emanated 220,222Rn a-activity has been elaborated. An increase of a-activity in time was measured using the emanation chamber equipped with a large area silicon epitaxial detector. The response functions for 224Ra and 226Ra sources were generated by Bateman's equations. Radium isotopes were preconcentrated from large volume of natural waters on cryptomelane MnO2, the inorganic ion exchanger selective for Ra2+. The elaborated method was applied to the fast determination of 224,226Ra in the oligocene, mineral and brine water samples.
PL
Opracowano szybką metodą jednoczesnego oznaczania izotopów radu (224-226) Ra oraz oszacowania zawartości (228) Ra przez pomiar emanowanych izotopów (220 i 222Ra. Narastanie aktywności promieniowania a w czasie mierzono w komorze emanacyjncj wyposażonej w detektor krzemowy o dużej powierzchni. Sporządzono krzywe narastania emisji promieniowania a dla wzorców 224Ra i 226Ra i aproksymowano je za pomocą równań Batemana. Izotopy radu były zatężane z dużych objątości wód naturalnych na złożu MnO, w formie kryptomelanu, który jest sorbentem selektywnym względem jonów Ra2+. Opracowana metoda została zastosowana do oznaczania izotopów (224,226) Ra w wodach oligoceńskich, mineralnych i solankach.
8
Content available remote Izotopy astatu w medycynie
Pruszyński M., Bilewicz A.
Postępy Techniki Jądrowej
|
2003
|
Vol. 46, z. 4
22--26
9
Content available Adsorption of 220Rn on dioxygenyl hexafluoroantimonate surface. A model experiment for studies of the chemistry of element 112
Bilewicz A., Łyczko K.
Nukleonika
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2003
|
Vol. 48, nr 3
137-139
EN
By comparison of the ionization potentials and ionic radius (estimated in this work) the chemical reactivity of element 112 is predicted. Due to the expected noble gas behaviour of element 112, we propose an investigation of adsorption of 220Rn on a dioxygenyl hexafluoroantimonate thin film surface as a model experiment for the chemistry of element 112.
10
Content available Preface
Bilewicz A.
Nukleonika
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2002
|
Vol. 47, nr 2
43-43
11
The Stereochemical Character of s2 Lone Pair in Bi3+ Aqua Cation
Włodzimirska B., Bilewicz A.
Polish Journal of Chemistry
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2001
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Vol. 75, nr 6
915-917
12
Content available remote Influence of relativistic effects on hydration and hydrolysis of rutherfordium, dubnium and some 6th row element cations
Bilewicz A., Siekierski S.
Nukleonika
|
1999
|
Vol. 44, nr 4
521-528
EN
New evidence for the influence of relativistic effects on coordination number, CN, and hydrolysis of Rf[indeks górny]4+ and Db[indeks górny]5+ aqua ions has been presented. It has been argued that very strong hydrolysis of the heaviest members of Groups 12, 13 is caused by the low CN of Hg2+ and Tl3+ in their aqua ions. Low CN is the result of relativistic effects which stabilize the 6s orbital, increasing thereby the respective promotion energy. That supports our previous view that strong hydrolysis of RF[indeks górny]4+[indeks dolny]aq much greater than that of HF[indeks górny]4+[indeks dolny]aq and Zr[indeks górny]4+[indeks dolny]aq, is also a result of lower CN. Since the promotion energy for sp3d4 hybridization (CN 8) seems to be close to that of sp3d2 hybridization (CN 6), and since hydration energies of Zr4+ Hf4+ and Rf4+ do not differ very much for hexa- and octahydrates the two aqua ions i.e., M(H2O)[indeks górny]4+[indeks dolny]6 and M(H2O)[indeks górny]4+[indeks dolny]8 may coexist in aqueous acid solutions. lHowever, due to relativistic stabization of 7s and destabilization of 6d orbitals, which increases promotion energy, the Rf[indeks górny]4+ aqua cation should show coordination number 6 rather than 8. A shift of equilibrium toward a lower hydrate increases the tendency to hydrolyse.
PL
Przedstawiono nowe dowody potwierdzające wpływ efektu relatywistycznego na liczbę koordynacyjną (LK) i hydrolizę akwojonów Rf[indeks górny]4+ i Db[indeks górny]5+. Dowiedziono, że bardzo silna hydroliza kationów najcięższych pierwiastków Grupy 12 i 13 jest związana z niską LK akwojonów Hg2+ i TI3+. Niska LK Hg[indeks górny]2+[indeks dolny]aq i TI[indeks górny]3+[indeks dolny]aq jest efektem relatywistycznej stabilizacji orbitalu 6s powodującej zwiększenie odpowiedniej energii promocji. Potwierdza to naszą wcześniejszą hipotezę, że silna hydroliza Rf[indeks górny]4+[indeks dolny]aq, dużo silniejsza niż Hf[indeks górny]4+[indeks dolny]aq i Zf[indeks górny]4+[indeks dolny]aq, jest także związana z jego niższą liczbą koordynacyjną. Ponieważ energia promocji dla hybrydyzacji sp3d4 (LK=8) wydaje się być bliska energii promocji dla hybrydyzacji sp3d2 (LK=6), nie powinny się też znacznie różnić energie hydratacji hexa- i oktahydratów Zr4+, Hf4+ i Rf4+. Dlatego w roztworach silnie kwaśnych mogą występować w równowadze kationy M(H20)[indeks górny]4+[indeks dolny]6 i M(H20)[indeks górny]4+[indeks dolny]8. Jednakże dla Rf[indeks górny]4+[indeks dolny]aq, w wyniku relatywistycznej stabilizacji orbitalu 7s oraz destabilizacji orbitali 6d powodującej zwiększenie energii promocji, następuje przesunięcie równowagi w stronę hydratów o niższej LK, co jest źródłem zwiększenia się jego tendencji do hydrolizy.
13
Content available remote Sorption of long-lived radionuclides from model liquid radioactive wastes on α-crystalline polyantimonic acid
Satyanarayana J., Bilewicz A., Narbutt J.
Nukleonika
|
1998
|
Vol. 43, nr 4
531-538
EN
A method was investigated for removal and immobilisation of hazardous long-lived radionuclides from liquid radioactive wastes containing macroamounts of other metal ions and complexing agents. Selective inorganic ion exchangers: α-crystalline polyantimonic acid (CAA) and metal antimonates were synthesized and studied as adsorbents for di- and trivalent ions: Sr(sup 2+) and Eu(sup 3+) (a model for actinides), and also monovalent Cs(sup +). High decontamination factors for the two former ions have been attained with CAA. The effect of the concentration of the waste components on the radionuclide sorption was studied. Calcium ions strongly reduce sorption of Sr(sup 2+), and EDTA in neutral solution - that of Eu(sup 3+), while sodium ions, citrates and oxalates have a little effect. Radiocaesium must be removed using another selective ion exchanger.
PL
Badano możliwości usuwania i związania w fazie stałej toksycznych radionuklidów długożyciowych z ciekłych odpadów promieniotwórczych zawierających makroilości jonów innych metali i związków chelatujących. Zsyntezowano selektywne nieorganiczne wymieniapze jonów: α-krystaliczny kwas poliantymonowy (CAA) i antymoniany metali wielowartościowych oraz zbadano ich własności sorpcyjne względem dwu- i trójwartościowych jonów strontu i europu (jako modelu aktynowców), a także jednowartościowego cezu. CAA okazał się bardzo efektywnym sorbentem dwóch pierwszych metali. Zbadano wpływ stężenia poszczególnych składników tych odpadów na sorpcję radionuklidów na CAA. Jony wapnia silnie zmniejszają sorpcję Sr(sup 2+), a EDTA w roztworach obojętnych sorpcję EU(sup 3+). Jony sodu, cytryniany i szczawiany mają niewielki wpływ na sorpcję Sr(sup 2)+ i EU(sup 3+). Radionuklidy Cs+ muszą być usuwane na innym sorbencie.
14
Content available remote A novel fast method for radium determination in low radioactive aqueous solutions by radon emanation from radium adsorbent
Kordyasz A. J., Bilewicz A.
Nukleonika
|
1998
|
Vol. 43, nr 4
489-498
EN
The method for fast measurement of (sup 226)Ra in low radioactive aqueous solutions by adsorption of radium on α-crystalline manganese dioxide and registration of α-particles from emanated (sup 222)Rn and its daughters has been elaborated. A large-area (64 cm2) silicon detector was used for a-particles registration. The method was tested using manganese dioxide samples with adsorbed (sup 226)Ra of radioactivity: 0.5 Bq, 1 Bq, 2 Bq, 10 Bq and 50 Bq, measured from 1 to 42 h. The time for chemical preparation of the sample and measurement was not greater than 6 h.
PL
Opracowano metodę szybkiego oznaczania (sup 226)Ra w niskoaktywnych roztworach wodnych poprzez sorpcję radu na α-krystalicznym dwutlenku manganu i rejestrację cząstek α z wyemanowanego radonu oraz produktów jego rozpadu. Metodę przetestowano stosując próbki dwutlenku manganu z zaadsorbowanym (sup 226)Ra o aktywnościach: 0.5 Bq, 1 Bq, 2 Bq, 10 Bq i 50 Bq, mierzone od 1 do 42 h. Czas potrzebny na przygotowanie próbki i pomiar nie przekracza 6 h.
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