Development of 99mTc-labelled complexes for imaging dopamine transporters in the brain

Technetium-99m (T_1/2=6h, 140keV) is the most commonly used short-lived radionuclide for diagnostic nuclear medicine imaging. It is important from an inorganic chemistry point of view to develop novel ligands and chelation chemistry associated with this radionuclide, because many patients could potentially benefit from advances in technetium chemistry. Recent studies showed that formation of tropane derivatives containing a neutral [Tc^VO]³⁺N₂S₂ complex are useful as dopamine transporter imaging agents. These agents may be important for the imaging of patients with Parkinson's and other neurodegenerative diseases.     

A novel method for the cyclotron production no-carrier-added <Superscript>93m</Superscript>Mo for nuclear medicine

Amongst the various radioisotopes of molybdenum, ^93mMo in its no-carrier added form might be a potential candidate radionuclide in the field of nuclear medicine due to its suitable half-life (T _1/2 = 6.85 h) and for its intense gamma line at 263.14 keV. Aim of the presented study is to compare the calculated cross sections for the production of ^93mMo incident proton energy up to 30 MeV, theoretical calculation of production yield and calculation of target thickness requirement. Also, deposition of ⁹³NbO₂ on Cu substrate was carried out via two special sedimentation methods for the production of ^93mMo and a simple and selective extraction of molybdenum was described.     

A study of samarium ions electroreduction at various electrodes in KCl-NaCl-CsCl melt at <Emphasis Type="Italic">T</Emphasis> = 823 K

Samarium ions electroreduction mechanism was studied on the supporting of KCl-NaCl-CsCl eutectic melt at 823 K on various electrodes (W, Mo, Al, Ni, Pt, and Ag). The diffusion coefficients of SmCl₆³⁻ chloride complexes and Sm³⁺ → Sm²⁺ heterogeneous recharge stage rate constant K _fh⁰ were calculated in KCl-NaCl-CsCl melt at T = 823 K.     

Surface characterization and thermodynamics of adsorption of Sr2+, Ce3+, Sm3+, Gd3+, Th4+, UO 2 2+ on activated charcoal from aqueous solution

Surface parameters of the activated charcoal were measured using precise instrumental techniques for dehydration, carbon content, trace metals impurities, anions, bulk, tap and true densities, surface area, pore volume, porosity and average particle diameter. The adsorption of Sr²⁺, Ce³⁺, Sm³⁺, Gd³⁺, Th⁴⁺ and UO ₂ ²⁺ ions on activated charcoal from aqueous solution was studied as a function of temperature. Thermodynamic parameters such as HH ⁰ and S ⁰ were calculated from the slopes and intercepts of the linear variation of lnK ₁ vs. 1/T, whereK ₃ is obtained from Langmuir equation. The results show endothermic heats of adsorption, but negative free energy values indicate that the adsorption process of metal ions on activated charcoal is favored at high temperature. The value of isosteric heat of adsorption, calculated from the Clausius-Clapeyron equation, shows that the surface of the activated charcoal is heterogeneous with respect to activity. A wavelength dispersive x-ray fluorescence spectrometer was used for measuring the concentration of metal ions.     

Radiolabeled phosphonates for bone metastases therapy

This study is focused on the chelating process of two phosphonates with biological activity and therapeutic potential, HEDP (1-hydroxy-ethylidene-diphosphonic acid) and TTHMP (triethylene-tetramine-hexamethylene-phosphonic acid) with therapeutic radiometals ¹⁸⁸Re (T _1/2 = 17 hrs, E _βmax = 2.12 MeV, E _γ= 155 keV) and ¹⁷⁷Lu (T _1/2 = 6.7 days, E _βmax = 490 keV, E _γ = 208 keV). The ligand structure effect on the in vitro stability and on the biological affinity of the therapeutic agents was investigated. The radiochemical purity of the labeled compounds was higher than 95%, showing a good in vitro stability, up to 48 hours. The in vivo biodistribution studies, performed in rats, show a rapid and quantitative accumulation of both labeled compounds in bones and rapid elimination via the urinary tract. The maximum values of the bone uptake were ranged from 75.14% (injected dose/g organ) for ¹⁸⁸Re-TTHMP to 94.10% for ¹⁷⁷Lu-TTHMP. The structure of the chelates determines the kinetic of bone accumulation processes of labeled phosphonates. Its influence on the biodistribution of the radiolabeled phosphonates reveals that luthetium forms more stable chelate with polyphosphonate in respect to diphosphonate. On the other hand, the less reactive rhenium coupled with HEDP shows a better in vivo behavior than Re-TTHMP.     

Potential use of tungstocerate matrices on the separation of <Superscript>113m</Superscript>In from <Superscript>110m</Superscript>Ag relevant to the separation of the cyclotron-produced <Superscript>111</Superscript>In from its silver target

A procedure for separation of no-carrier-added ^113mIn(III) radioisotope from a bulk of ^110mAg has been developed. The sorption behavior of ^113mIn(III) and ^110mAg(I) ions in HNO₃ acid solutions on different tungstocerate matrices showed high affinity of ^110mAg(I) ions towards tungstocerate(IV) gel matrices compared with ^113mIn(III) ions. No-carrier-added ^113mIn radionuclide was separated from ^110mAg on 12-tungstocerate(IV) column matrix. 11 mL 0.3M HNO₃ acid solution was enough for eluting the ^113mIn from the column bed. ^110mAg was recovered from the column by eluting the column bed with 12 mL 2M HNO₃ acid solution.     

A new alpha-emitter for nuclear medicine: 230U

Summary The limited number of radionuclides emitting alpha-particles and their limited availability is discussed. A new alpha-emitter ²³⁰U (T_1/2 = 20.8 d, 100% a) is suggested and its preparation from thorium target bombarded by accelerated protons (via initial formation of ²³⁰Pa (T_1/2 = 17.4 d, 8.4% decay to ²³⁰U)), or ⁴He is discussed. The Empire II model was used to calculate the excitation functions for the different products from bombardment of Th by protons. The calculated thick target yield for ²³⁰Pa is 0.6 mCi/mA ^. h, leading to about 24 mCi/mA ^. h of ²³⁰U or about 150 mCi/mA ^. h in the case of alpha-bombardment.     

Medium energy,heavy and inert ion irradiation of metallic thin films: studies of surface nano‐structuring and metal burrowing

In context to the ion induced surface nanostructuring of metals and their burrowing in the substrates, we report the influence of Xe and Kr ion‐irradiation on Pt:Si and Ag:Si thin films of ~5‐nm thickness. For the irradiation of thin films, several ion energies (275 and 350 keV of Kr; 450 and 700 keV of Xe) were chosen to maintain a constant ratio of the nuclear energy loss to the electronic energy loss (S_n/S_e) in Pt and Ag films (five in present studies). The ion‐fluence was varied from 1.0 × 10¹⁵ to 1.0 × 10¹⁷ ions/cm². The irradiated films were characterized using Rutherford backscattering spectroscopy (RBS), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The AFM and SEM images show ion beam induced systematic surface nano‐structuring of thin films. The surface nano‐structures evolve with the ion fluence. The RBS spectra show fluence dependent burrowing of Pt and Ag in Si upon the irradiation of both ion beams. At highest fluence, the depth of metal burrowing in Si for all irradiation conditions remains almost constant confirming the synergistic effect of energy losses by the ion beams. The RBS analysis also shows quite large sputtering of thin films bombarded with ion beams. The sputtering yield varied from 54% to 62% by irradiating the thin films with Xe and Kr ions of chosen energies at highest ion fluence. In the paper, we present the experimental results and discuss the ion induced surface nano‐structuring of Pt and Ag and their burrowing in Si. Copyright © 2016 John Wiley & Sons, Ltd.     

Control of the Fluorescence of DNA‐templated Silver Nanoclusters by Adenosine Triphosphate and Mercury(II)

Several DNA templates with the sequence 5′‐T _n TAACCCCTAACCCCT ‐3′ (n = 0, 15, 30, and 45) were used to prepare DNA template–silver nanoclusters (DNA –Ag NCs ). The T _n sequence acts as a recognition element for Hg²⁺, while the rest of the sequence acts as a template for DNA –Ag NCs . At pH 3.0, the fluorescence intensity of DNA –Ag NCs is enhanced by ATP , and the enhanced fluorescence is quenched by Hg²⁺. The length of polyT shows a slight effect on the sensitivity for the detection of Hg²⁺ but almost no effect on the optical properties of DNA –Ag NCs . The fluorescence response of DNA –Ag NCs (T₁₅‐DNA –Ag NCs ) vs. Hg²⁺ concentration shows two linear ranges over 10–100 and 100–1000 nM , mainly because of the fluorescence quenching due to DNA conformational changes through T–Hg²⁺–T coordination and the formation of an amalgam with Ag NCs , respectively. The sensitivity of the T₁₅‐DNA –Ag NC probe was validated through the analysis of Hg²⁺ in spiked pond water. Based on the switch‐on and switch‐off fluorescence properties of T₁₅‐DNA –Ag NCs , an IMPLICATION logic gate was fabricated using the concentrations of ATP and Hg²⁺ as inputs and the fluorescence intensity at 585 nm as output.     

Scavenging of UO2 2+ using 4-sulfonic calix[6]arene in the presence of goethite

The scavenging of UO₂ ²⁺ using 4-sulfonic calix[6]arene in the presence of a strong adsorbent was studied as a function of pH. The adsorbent selected was goethite because of its strong affinity for UO₂ ²⁺ and its abundance in natural soils. In order to understand the underlying chemistry of the scavenging process, the adsorption of UO₂ ²⁺ and 4-sulfonic calix[6]arene onto goethite, respectively, and the extraction of adsorbed UO₂ ²⁺ from goethite surface were modeled using the triple-layer model. The model well explained the pH dependence of the adsorption and extraction processes. This work showed that maximum extraction was obtained around pH 10.5 in the presence of 12g/l goethite in the case of a 1:3T _U(VI):T _calixareneratio.     

A novel technique for simultaneous diagnosis and radioprotection by radioactive cerium oxide nanoparticles: study of cyclotron production of <Superscript>137m</Superscript>Ce

Application of nanoparticles in nuclear medicine has aimed to develop diagnosis and therapeutic techniques. Cerium oxide nanoparticles (CNPs) are expected to be useful for protection of healthy tissue from radiation-induced harm and could serve therapeutic function. Among a variety of cerium radioisotopes, ^137mCe (T _1/2 = 34.4 h, IT (99.22%), β⁺ (0.779%)) could be a novel candidate radionuclide in the field of diagnosis owing to its appropriate half-life, 99.91% natural abundance of target and its intense gamma line at 254.29 keV. In this study, ^137mCe excitation function via the ^natLa(p,3n) reaction was calculated by TALYS-1.2 and EMPIRE-3 codes. The excitation function calculations demonstrated that the ^natLa(p,3n)^137mCe reaction leads to the formation of the ^136/138Ce isotopic contamination in the 22–35 MeV energy range. Interestingly, the isotopic impurities of ^137mCe could serve radio protector function. Overall results indicate that the cyclotron produced ^137mCeO₂ nanoparticles by irradiation of a target encompassing lanthanum oxide nanoparticles could be a potent alternative for conventional diagnostic radionuclides with simultaneous radioprotection capacity.     

Temperature Influence on the Morphology and Roughness of Silver Deposit Formed by Cementation

The morphology and surface roughness of silver deposits formed by cementation in 0.5M H₂SO₄ solution containing 0.5M CuSO₄ was investigated at various temperatures. The influence of O₂ on the morphology of deposited Ag on the Cu surface was studied in solutions containing 20 or 100 mg/dm³ initial Ag⁺. Surface‐height‐distribution diagrams were calculated from scanning‐electron‐microscopic (SEM) images. For the lower Ag⁺ concentration, the formation of granular deposits occurred in the presence of O₂. In contrast, under anaerobic conditions, rather flat deposits with tiny Ag crystals were observed. For the higher Ag⁺ concentration, the presence of O₂ did not significantly affect the morphology of the Ag deposit, but increasing temperature resulted in more‐compact and denser dendrites. Differences in the Ag‐deposit morphology and surface roughness were attributed to a different mechanism in the absence of O₂. Under anaerobic conditions, a competitive reaction between Ag⁺ and Cu⁺ occurs in bulk solution, which consumes additional Ag⁺ ions. The SEM images and, especially, distribution diagrams of the surface height provided useful information on the formation and expansion of anodic sites on the Cu surface at various temperatures.     

Formation mechanism of nanostructured Ag films from Ag2O particles using a sonoprocess

Nanostructured Ag films composed of nanoparticles and nanorods can be formed by the ultrasonication of ethanol solutions containing Ag₂O particles. The present work examined the formation process of these films from ethanol solutions by two different agitation methods, including ultrasonication and mechanical stirring. The mass-transfer process from Ag₂O particles to ethanol solvent is accelerated by the mechanical effects of ultrasound. Ag⁺ ions and intermediately reduced Ag clusters were released into the ethanol. These Ag⁺ ions and Ag clusters provide absorption bands at 210, 275 and 300 nm in UV-vis spectra. These bands were assigned to the absorption of Ag⁺, Ag ₄ ²⁺ and Ag_n (n?≈?3). The Ag_n clusters that readily grow to become Ag nanoparticles were formed due to the surface reaction of Ag₂O particles with ethanol under ultrasonication. The reactions of Ag⁺ ions in ethanol to form Ag nanomaterials (through the formation of Ag ₄ ²⁺ clusters) were also accelerated by ultrasonication.     

A fast and simple method for the estimation of natural uranium in urine

Natural uranium (U) in urine was co-precipitated with Ca₃(PO₄)₂ and then with BiPO₄ after reducing uranyl ions from +6 to +4 state. U separated from BiPO₄ was then quantified by measuring its absorbance after complexing it with Arsenazo-III. The interference caused by ions such as Fe³⁺, Bi³⁺, Zn²⁺ and PO₄ ³⁻ was studied during the measurement of U absorbance. The percent recovery of U was 81.4±2.6 for 5 to 30 μg U present in 500 ml urine. The minimum detectable concentration of U was 2 μg/l and the time required to complete the analysis was 2 days.     

<Superscript>234</Superscript>U/<Superscript>235</Superscript>U activity ratios as a probe for the <Superscript>238</Superscript>U/<Superscript>235</Superscript>U half-life ratio

High-resolution alpha-particle spectrometry was performed on three uranium materials enriched in ²³⁵U. Besides the ²³⁵U peaks, separate peaks belonging to impurity traces of ²³⁴U could be quantified. Relying on the isotopic composition of the uranium, as determined by mass spectrometry, the ratio of the half-lives of ²³⁸U and ²³⁵U was determined via the activity ratio of ²³⁴U and ²³⁵U in the materials. As an intermediate link, the ²³⁴U/²³⁸U half-life ratio was taken from published mass spectrometric analyses of ‘secular equilibrium’ uranium material. The resulting half-life ratio T _1/2(²³⁸U)/T _1/2(²³⁵U) = 6.351±0.031 is in agreement with the commonly adopted half-life values determined by Jaffey et al.     

Thermodynamics of nucleic acid bases and nucleosides in water from 25 to 55°C

Specific heat capacities, apparent molar heat capacities, densities, and apparent molar volumes have been determined for cytosine, uracil, thymine, adenine, cytidine, 2-deoxycytidine, uridine, thymidine and adenosine at temperatures from 25°C to 55°C. The results of these measurements have been used to calculate for the first time, the thermodynamic quantities:C _p,2 ^o , (C _p,2 ^o /T)_p, (² C _p,2 ^o T ²)_p,V ₂ ^o , (V ₂ ^o /T)_p, and (² V ₂ ^o /T ²)_p. The-CH₂-group contribution has been calculated at different temperatures. It has also been observed from the data for the nucleic acid bases and nucleosides that the additivity ruleC _p,2 ^o (nucleoside)-C _p,2 ^o (base) +C _p,2 ^o (water)=C _p,2 ^o (ribose) does not hold in these cases.     

多级Ag/Bi/氮空位g-C3N4/Ti3C2Tx肖特基结的构筑及其全光谱催化性能

采用原位溶剂热反应制备多级 Ag/Bi/Nv-g-C₃N₄(氮空位-g-C₃N₄)/Ti₃C₂T_x肖特基结, 并对其物相组成和晶体结构、微观形貌和孔结构、表面元素组成和化学态、光学和光电化学性质进行了表征。由于 Ag、Bi和 Ti₃C₂T_x协同的表面等离激元共振效应,Ag/Bi/Nv-g-C₃N₄/Ti₃C₂T_x表现出全光谱吸收特性。由载流子浓度差驱动的界面极化电荷转移诱导形成的肖特基结, 显著提高了光生载流子(包括热电子和热空穴)的分离效率和利用率。因此, 与 Nv-g-C₃N₄、Ti₃C₂T_x、Ag/Nv-g-C₃N₄、Bi/Nv-g-C₃N₄和 Ag/Bi/Nv-g-C₃N₄相比, Ag/Bi/Nv-g-C₃N₄/Ti₃C₂T_x表现出显著增强的全光谱催化活性, 其在可见光和近红外光照射下光催化降解四环素的反应速率常数分别为 0.033和 0.008 6 min^-1, 为对比样品的 10~2.1倍和 8.6~1.8倍。     

多级Ag/Bi/氮空位g-C3N4/Ti3C2Tx肖特基结的构筑及其全光谱催化性能

采用原位溶剂热反应制备多级Ag/Bi/Nv-g-C₃N₄(氮空位-g-C₃N₄)/Ti₃C₂T_x肖特基结,并对其物相组成和晶体结构、微观形貌和孔结构、表面元素组成和化学态、光学和光电化学性质进行了表征。由于Ag、Bi和Ti₃C₂T_x协同的表面等离激元共振效应,Ag/Bi/Nv-g-C₃N₄/Ti₃C₂T_x表现出全光谱吸收特性。由载流子浓度差驱动的界面极化电荷转移诱导形成的肖特基结,显著提高了光生载流子(包括热电子和热空穴)的分离效率和利用率。因此,与Nv-g-C₃N₄、Ti₃C₂T_x、Ag/Nv-g-C₃N₄、Bi/Nv-g-C₃N₄和Ag/Bi/Nv-g-C₃N₄相比,Ag/Bi/Nv-g-C₃N₄/Ti₃C₂T_x表现出显著增强的全光谱催化活性,其在可见光和近红外光照射下光催化降解四环素的反应速率常数分别为0.033和0.008 6 min^-1,为对比样品的10~2.1倍和8.6~1.8倍。     

Polyatomic ions in inductively coupled plasma–mass spectrometry: Part II: Origins of N2H and HxCO ions using experimental measurements combined with calculated energies and structures

Several polyatomic ions in inductively coupled plasma–mass spectrometry are studied experimentally and by computational methods. Novel calculations based on spin-restricted open shell second order perturbation theory (ZAPT2) and coupled cluster (CCSD(T)) theory are performed to determine the energies, structures and partition functions of the ions. These values are combined with experimental data to evaluate a dissociation constant and gas kinetic temperature (T_gas) value. In our opinion, the resulting T_gas value can sometimes be interpreted to deduce the location where the polyatomic ion of interest is generated. The dissociation of N₂H⁺ to N₂⁺ leads to a calculated T_gas of 4550 to 4900 K, depending on the computational data used. The COH⁺ to CO⁺ system yields a similar temperature, which is not surprising considering the similar energies and structures of COH⁺ and N₂H⁺. The dissociation of H₂CO⁺ to HCO⁺ leads to a much lower T_gas (< 1000 to 2000 K). Finally, the dissociation of H₂COH⁺ to HCOH⁺ generates a T_gas value between those from the other H_xCO⁺ ions studied here. All of these measured T_gas values correspond to formation of extra polyatomic ion in the interface or extraction region. The computations reveal the existence of isomers such as HCO⁺ and COH⁺, and H₂CO⁺ and HCOH⁺, which have virtually the same m/z values and need to be considered in the interpretation of results.