Comparative Studies on the Development of a 188W-188Re Generator

A comparative study on the sorption behaviour of tungsten and rhenium between anion exchange resin, charcoal and alumina and aqueous media of HNO₃, HCl and NaCl were carried out. The equilibrium distribution coefficient obtained for the different systems were evaluated and discussed in terms of the separation factor between W and Re. It is found that the systems based on alumina and HCl or NaCl are the most promising systems to be used for development of ¹⁸⁸W-¹⁸⁸Re generator. The capacity of a chromatographic column loaded with alumina for ¹⁸⁸W from 0.01 M HCl, 0.7% NaCl and 1.2% NaCl was found to equals 75.3, 91.0 and 126.0 mg/cm, respectively. A recommended procedure was adopted for ¹⁸⁸W-¹⁸⁸Re generator.

Es wurde eine Vergleichsuntersuchung zum Sorptionsverhalten von W und Re zwischen einem Anionenaustauscherharz einer Aktivkohle und einer Tonerde und den wüβirigen Lösungen von HN0₃, HCl and NaCl ausgeführt. Die Gleichgeiwichlsverteilungskoeffizienten der unterschiedlichen Systeme wurden bestimmt und als Trennfaktoren zwischen W und Re diskutiert. Es wurde gefunden, daβ sich das System Tonerde/HCl oder NaCl sehr als Trennsystem für die Entuwicklung eines ¹⁸⁸W¹⁸⁸Re-Generators eignet. Die Kapazitäten einer mit Tonerde gefüllten Säule für ¹⁸⁸W mit 0.01 M HCl, 0.7% NaCl und 1.2% NaCl betrugen entsprechend 75.3, 90.0 und 126.0 mg/cm. Es wird eine geeignete Trennmethode für einen ¹⁸⁸.¹⁸⁸ Re-Generator empfohlen.     

Influence of the rhenium carrier in eluate of Re-188 on its binding with potassium-sodium salt of hydroxyethylidene biphosphonic acid

The results of investigation of the regularity of ¹⁸⁸Re binding with KNaHEDP and hydrolysis of the complex compound (¹⁸⁸Re-KNaHEDP) have shown that its quality depends to a considerable extent on the reaction conditions. Concentrations of a reducing agent (Sn²⁺) and stable rhenium in the ¹⁸⁸Re eluate, as the carrier, influence essentially the rate of formation and stability of ¹⁸⁸Re complex with KNaHEDP. The results of the kinetic investigations of the ¹⁸⁸Re-KNaHEDP complex formation prove that the reaction character bears a direct relationship to the concentrations of the complexing agent (Re) and the reducer (Sn²⁺). The higher ratio of Re⁷⁺: Sn²⁺ concentrations, the more effectively ¹⁸⁸Re binds with KNaHEDP. The obtained results prove that for ¹⁸⁸Re binding with KNaHEDP with the efficiency not less than 95% the optimum concentration of stable rhenium in the reaction mixture is 0.54×10⁻⁶ mol·ml⁻¹ (0.1 mgMml⁻¹) and the ratio of Re⁷⁺: Sn²⁺ concentrations should not be lower than 10: 1.     

Specific energy from Auger and conversion electrons of 131I, 188Re-anti-CD20 to a lymphocyte's nucleus

The typical radionuclides used to label anti-CD20 in the treatment of non-Hodgkin's lymphoma are ⁹⁰Y, ¹³¹I, and ¹⁸⁸Re, with the emission of beta particles, Auger electrons, and conversion electrons for the latter two. The aim of the present work was to calculate the contribution of high linear energy transfer radiation as Auger electrons (AE) and conversion electrons (CE) of ¹³¹I and ¹⁸⁸Re-anti-CD20 to mean specific energy into the cell nucleus by Monte Carlo simulation (MCS), so as to infer therapeutic effectiveness on a dosimetric basis. MCS was used to quantify the frequency–mean specific energy into the cell nucleus, where the cell was modeled by two concentric spheres, considering two cell models. The results showed that 10% and 33% of the mean-specific energies (z¯) per disintegration imparted to the cell nucleus for both geometries are due to AE and CE; on the other hand, if the hit of AE and CE occurs, the contribution to (z¯) is about 64% and 86% for ¹³¹I and ¹⁸⁸Re, respectively. According to the amount of specific energy from AE and CE into the cell nucleus by positive event, they can cause catastrophic effects in the nuclear DNA in the treatment of non-Hodgkin's lymphoma with ¹³¹I, ¹⁸⁸Re-anti-CD20.     

Radionuclide 188Re-Loaded Photothermal Hydrogel for Cancer Theranostics

Herein, an injectable photothermal hydrogel system containing a therapeutic radionuclide ¹⁸⁸Re is studied for combined radioisotope therapy and photothermal therapy (PTT) of cancer. A dopamine-conjugated poly(α,β-aspartic acid) copolymer (PDAEA) is used to trigger a sol–gel phase transition in mixture with Fe³⁺ ions, rapidly forming a gel by simply mixing PDAEA and FeCl₃ phosphate buffer saline solutions. The injectable hydrogel exhibits strong near-infrared light absorbance and can efficiently convert light into a heating effect for local PTT treatment. The obtained hydrogel possesses a porous 3D microstructure, and can be utilized for radionuclide loading. After the Na¹⁸⁸ReO₄ loading, the hydrogel is intratumorally injected into the tumor of mice bearing 4T1 murine breast cancer cells for studying the tumor retention and therapeutic efficiency. In vivo results show that Na¹⁸⁸ReO₄-loaded hydrogel exhibits significantly longer time in the tumor sites than that of free Na¹⁸⁸ReO₄. The tumor growth of mice treated with Na¹⁸⁸ReO₄-loaded hydrogel under near-infrared radiation is significantly inhibited compared with control groups. Therefore, the results show that the developed strategy using an injectable and biocompatible hydrogel may promote the applications of radioisotope therapy and photothermal therapy for cancer.     

Electric quadrupole and magnetic dipole moments of the first excited 2+ states of186Os and188Os

The spectroscopic quadrupole moments and the magnetic dipole moments of the lowest 2⁺ states in¹⁸⁶Os (137 keV) and¹⁸⁸Os (155 keV) have been determined by Mößbauer transmission experiments. The electric quadrupole momentsQ ₂₊(Os 186)=? (1.80±0.22) b andQ ₂₊(Os 188)=?(1.81±0.24) b as well as their ratioQ ₂₊(Os 188)/Q ₂₊(Os 186)=1.00±0.07 within the limits of error agree withB(E2) data, if a comparison on the basis of the rotational model is made. For the g-factors and their ratio g₂₊(Os 186)=0.281±0.008, g₂₊(Os 188)=0.305±0.015 andg ₂₊(Os 188)/g ₂₊(Os 186)=1.08±0.05 was obtained. All results are compared with recent model calculations.     

Levels of 188os populated in the 189Os(d,t)188Os reaction and in the decay of 41h 188Ir

The 0 level structure of ¹⁸⁸Os has been investigated by the ¹⁸⁹Os(d, t)¹⁸⁸Os reaction using a broad range magnetic spectrograph, and the properties of the ¹⁸⁸Os levels populated in the decay of ¹⁸⁸Ir have been re-examined. The (d, t) results yield new information about the location of two-neutron excitations in ¹⁸⁸Os involving the $\text{3}\text{2}$[512] orbital. Since the ¹⁸⁸Os ground state contains admixtures of both $\text{K =}\text{3}\text{2}\text{and}\text{K =}\text{1}\text{2}$ character, cross-section formulae for single-neutron transfer from a target state which is not pure in K are considered, and it is found that rather small $\text{K =}\text{1}\text{2}$ admixtures in the ¹⁸⁹Os ground state give rise to striking interference effects, which are manifested in the experimental (d, t) cross sections into the members of the ¹⁸⁸Os ground state band. The consequences of the mixed character of the target state on the (d, t) population of members of the K^π = 2⁺ γ-vibration and of higher-lying two-quasiparticle bands are also discussed.     

Absolute frequency measurement of a CO2/OsO4 stabilized laser at 28.8 THz

A cw carbon dioxide laser operating on the 10 μm R(0)_I transition (28.832 THz) was frequency stabilized by a servo lock to the saturated absorption dip of the Q(15) transition of ¹⁸⁸OsO₄. The laser frequency was measured with a cesium-clock-based frequency chain. In addition, the absorption line frequencies Q(14) of ¹⁸⁸OsO₄ and sQ(4,3) of ¹⁵NH₃, were measured relative to the frequency of Q(15). Received: 21 August 2000 / Revised version: 15 January 2001 / Published online: 30 March 2001     

Excited states of 188Ir populated by the (α, 3n) reaction

The deexcitation of states in ¹⁸⁸Ir, formed through the ¹⁸⁷Re(α, 3n)¹⁸⁸Ir reaction, was studied using in-beam and off-beam gamma and electron spectroscopy techniques. A new level scheme, exhibiting a rather high level density, is presented. An interpretation of the structure of these states is attempted using information on one-quasiparticle intrinsic states from neighboring oddproton and odd-neutron nuclei.     

Superparamagnetic silica nanoparticles with immobilized metal affinity ligands for protein adsorption

Superparamagnetic silica-coated magnetite (Fe₃O₄) nanoparticles with immobilized metal affinity ligands were prepared for protein adsorption. First, magnetite nanoparticles were synthesized by co-precipitating Fe²⁺ and Fe³⁺ in an ammonia solution. Then silica was coated on the Fe₃O₄ nanoparticles using a sol–gel method to obtain magnetic silica nanoparticles. The condensation product of 3-Glycidoxypropyltrimethoxysilane (GLYMO) and iminodiacetic acid (IDA) was immobilized on them and after charged with Cu²⁺, the magnetic silica nanoparticles with immobilized Cu²⁺ were applied for the adsorption of bovine serum albumin (BSA). Scanning electron micrograph showed that the magnetic silica nanoparticles with an average size of 190 nm were well dispersed without aggregation. X-ray diffraction showed the spinel structure for the magnetite particles coated with silica. Magnetic measurement revealed the magnetic silica nanoparticles were superparamagnetic and the saturation magnetization was about 15.0 emu/g. Protein adsorption results showed that the nanoparticles had high adsorption capacity for BSA (73 mg/g) and low nonspecific adsorption. The regeneration of these nanoparticles was also studied.     

New levels observed in188Os from the decay of188Re

The level structure of¹⁸⁸Os has been investigated following the decay of 17h¹⁸⁸Re. The energies and relative intensities of 41 gamma rays were determined using large volume high resolution Ge(Li) detectors. The decay was observed to populate the 0⁺ states at 1478 and 1704 keV which were recently observed in (p, t) reaction studies. Additional states at 1414 and 1843 keV were also observed in the decay.     

Study of the side band in 188Pt

Low-lying levels in ¹⁸⁸pt were studied using the ¹⁹¹Ir(p, 4nγ)¹⁸⁸Pt reaction and higher spin members of the quasi-γ band were proposed. The results resemble a slightly perturbed phonon scheme, from comparisons with macroscopic calculations which would remove the degeneracy of the phonon multiplets. The importance of mass parameter renormalization is pointed out.     

Evaluation of the impact of chitosan/DNA nanoparticles on the differentiation of human naive CD4+ T cells

Chitosan (CS) is one of the most widely studied polymers in non-viral gene delivery since it is a cationic polysaccharide that forms nanoparticles with DNA and hence protects the DNA against digestion by DNase. However, the impact of CS/DNA nanoparticle on the immune system still remains poorly understood. Previous investigations did not found CS/DNA nanoparticles had any significant impact on the function of human and murine macrophages. To date, little is known about the interaction between CS/DNA nanoparticles and naive CD4⁺ T cells. This study was designed to investigate whether CS/DNA nanoparticles affect the initial differentiation direction of human naive CD4⁺ T cells. The indirect impact of CS/DNA nanoparticles on naive CD4⁺ T cell differentiation was investigated by incubating the nanoparticles with human macrophage THP-1 cells in one chamber of a transwell co-incubation system, with the enriched human naive CD4⁺ T cells being placed in the other chamber of the transwell. The nanoparticles were also co-incubated with the naive CD4⁺ T cells to explore their direct impact on naive CD4⁺ T cell differentiation by measuring the release of IL-4 and IFN-?? from the cells. It was demonstrated that CS/DNA nanoparticles induced slightly elevated production of IL-12 by THP-1 cells, possibly owing to the presence of CpG motifs in the plasmid. However, this macrophage stimulating activity was much less significant as compared with lipopolysaccharide and did not impact on the differentiation of the naive CD4⁺ T cells. It was also demonstrated that, when directly exposed to the naive CD4⁺ T cells, the nanoparticles induced neither the activation of the naive CD4⁺ T cells in the absence of recombinant cytokines (recombinant human IL-4 or IFN-??) that induce naive CD4⁺ T cell polarization, nor any changes in the differentiation direction of naive CD4⁺ T cells in the presence of the corresponding cytokines.     

Observation of a πh9/2 ⊗ νi13/2 oblate band in 188Tl

Excited states in ¹⁸⁸Tl have been studied experimentally using the ¹⁵⁷Gd (³⁵Cl, 4n) reaction at a beam energy of 170MeV. A rotational band built on the πh _9/2 ⊗ νi _13/2 configuration with oblate deformation has been established for ¹⁸⁸Tl. Based on the structure systematics of the oblate πh _9/2 ⊗ νi _13/2 bands in the heavier odd-odd Tl nuclei, we have tentatively proposed spin values for the new band in ¹⁸⁸Tl. The πh _9/2 ⊗ νi _13/2 oblate band in ¹⁸⁸Tl shows low-spin signature inversion, and it can be interpreted qualitatively by the two-quasiparticle plus rotor model including a J-dependent p-n residual interaction.     

The α-decay rate of 188Pb

As part of our investigation of the reported anomalous α-decay rates of even-even lead nuclei with A ≦ 192 we have measured the α-decay branching ratio of ¹⁸⁸Pb. The isotope was produced in the ¹⁸⁰W(¹⁶O, 8n) reactions, and its decay properties were investigated with the use of the Oak Ridge on-line isotope separator facility. Gamma-ray and α-particle spectra were measured with the detectors placed in calibrated geometries. From these measurements the ¹⁸⁸Pb α-decay branching ratio was determined to be (22 ± 7)%, a value about seven times greater than that available in the literature. This result, together with our recent data for ¹⁹⁰Pb and ¹⁹²Pb, is discussed within the context of α-decay-rate systematics in the lead region.     

On the Eisenbud-Wigner formula for time-delay

It is shown that the Eisenbud-Wigner relation for time-delay holds for potentials V(r) that are O(r ^-5/2-) at . This improves previous results in which V was required to be O(r ^-4-) and O(r ^-3-), respectively.     

Electric quadrupole orientation of iridium isotopes in rhenium

The quadrupole frequenciese ² qQ/h, for^{186, 188–190}Ir in a Re single crystal have been determined by nuclear orientation at temperatures down to 2 mK. Using a modeldependent value of +1.0 b for the quadrupole moment of the ground state of¹⁸⁹Ir, the electric field gradient of IrRe at 0 K is found to be–3.6×10¹⁷ V·cm^–2. The value is consistent with systematics proposed by Raghavan et al. Using this EFG, quadrupole moments are deduced for^{186, 188, 190}Ir.     

Double resonance NMR-on study on oriented188Ir in iron

The quadrupole splitting of oriented¹⁸⁸Ir in iron was studied at 8.6 mK using a double resonance NMR-ON method. With r.f. power applied at the strongest resonance frequency, a second frequency was used to simultaneously investigate the second resonance component, where the splitting is caused by an electric quadrupole interaction. The electric hyperfine splitting frequency ν_Q=e ² qQ/h was measured to be 3.37(11) MHz. With the known electric field gradient of −0.283(6)×10¹⁷ V/cm² at Ir in iron, the spectroscopic quadrupole moment of¹⁸⁸Ir was deduced to be 0.492(26)b. The present results show that the double resonance method is a powerful tool in establishing the quadrupole splitting, if it leads to well-resolved NMR-ON resonance components.     

Enzymes immobilization on Fe3O4-gold nanoparticles

In the present study Fe₃O₄ magnetic nanoparticles were synthesized by coprecipitation of Fe²⁺ and Fe³⁺ from chlorides. In the next step magnetite-gold core-shell nanoparticles were synthesized from HAuCl₄ using an ethanol as a reducing agent. Finally, magnetic nanoparticles were functionalized by hexadecanethiol. The immobilization of biological molecules (trypsin and glucose oxidase) to the thiol-modified and unmodified magnetite-gold nanoparticles surface was tested. The resulting nanoparticles were characterized by infrared spectroscopy, differential scanning calorimetry, Mössbauer spectroscopy and transmission electron microscopy.     

The Spin Density Distribution in the Hydrocarbon Radical Anions

In this note we wish to report our calculations of the spin density distribution in the several hydrocarbon radical anions using the “half-electron” SCF MO [variable beta] method of Dewar^1,2. This method calculates the energy of a system in which the unpaired electron is replaced by two “half-electrons” of the opposite spin. In this way one has the pseudo closed-shell system at equilibrium geometry and the resulting energy [E] differs from that [E_o] given by Roothaan's³ procedure only for ¼ J_mm

E_o=E - ¼ J_mm

Term ¼ J_mm represents the correction due to the spurious repulsion of the two “half-electrons”.     

Silver nanoparticles produced by PLD in vacuum: role of the laser wavelength used

In this work we report the results of investigation of silver (Ag) nanoparticles prepared on a silica substrate by laser ablation. Our attention was focused on the mean diameter, size distribution and optical absorption properties of nanoparticles prepared in vacuum by using different laser wavelengths. The fundamental wavelength and the second, third, and fourth harmonics of a nanosecond Nd:YAG laser were used for nanoparticles fabrication. The corresponding values of the laser fluence for each wavelength were: 0.6 J/cm² at 266 nm, 0.8 J/cm² at 355 nm, 2.8 J/cm² at 532 nm, and 2 J/cm² at 1064 nm. The Ag nanoparticles produced have mean diameters in the range from 2 nm to 12 nm as the nanoparticles’ size decreases with the decrease of the wavelength used. The presence of the Ag nanoparticles was also evidenced by the appearance of a strong optical absorption band in the measured UV-VIS spectra associated with surface plasmon resonance (SPR). A redshift and widening of the absorption peak were observed as the laser wavelength was increased. Some additional investigations were performed in order to clarify the structure of the Ag nanoparticles.