Radiosynthesis and biological evolution of <Superscript>99m</Superscript>Tc(CO)<Subscript>3</Subscript>–sitafloxacin dithiocarbamate complex: a promising <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> infection radiotracer

Garenoxacin (GXN) was modified to its dithiocarbamate followed by radiolabeling with technetium-99m (^99mTc) through [^99mTc-N]²⁺ core. The suitability of the ^99mTcN–Garenoxacin dithiocarbamate (GXND) complex as a potential multiresistant Staphylococcus aureus (MDRSA) and penicillin-resistant Streptococci (PRSC) infection radiotracer was assessed in artificially infected rats (AFRT). The radiolabeled complex was investigated for its radiochemical purity (RCP), permanence in serum using HPLC and TLC methods. In vitro binding with MDRSA and PRSC was performed at 37 °C. The ^99mTcN–GXND showed maximum RCP of 98.00 ± 0.22% and remained more than 90% stable up to 4 h. The ^99mTcN–GXND showed saturated in vitro binding with living MDRSA and PRSC, respectively. The complex showed normal biodistribution in healthy rats (HRT), however in AFRT, seven fold uptakes was observed in infected muscle as compared to inflamed and normal muscles. Based on the high RCP, stability in serum, better in vitro binding with bacteria, biodistribution behavior and the target to non-target (infected to inflamed muscle) ratio, we recommend the ^99mTcN–GXND complex for in vivo investigation of MDRSA and PRSC infection in human.     

Synthesis,biological evaluation and biodistribution of the <Superscript>99m</Superscript>Tc–Garenoxacin complex in artificially infected rats

The labeling of garenoxacin (GXN) with technetium-99m (^99mTc) using different concentrations of GXN, sodium pertechnetate (Na^99mTcO₄), stannous chloride dihydrate (SnCl₂·2H₂O) at different pH was investigated and evaluated in terms of in-vitro stability in saline, serum, binding with multi-resistant Staphylococcus aureus (MDRSA) and penicillin-resistant Streptococci (PRSC) and its biodistribution in artificially MDRSA and PRSC infected rats. ^99mTc–GXN complex with 97.45 ± 0.18% radiochemical stability was prepared by mixing 3 mg of GXN with 3 mCi of Na^99mTcO₄ in the presence of 150 μL of SnCl₂·2H₂O (1 μg/μL in 0.01 N HCl) at a pH 5.6. The radiochemical stability of the complex was evaluated in normal saline up to 240 min of reconstitution. It was observed that the complex showed maximum RCP values after 30 min of the reconstitution and remained more than 90% up to 240 min. The complex showed radiochemical stability in normal saline at 37 °C up to 16 h with a 17.80% de-tagging. The complex showed saturated in-vitro binding with living MDRSA and PRSC as compared to the insignificant binding with heat killed MDRSA and PRSC. Biodistribution behavior of the complex was assessed in artificially infected with living and heat killed MDRSA and PRSC rats. It was observed that the accumulation of the complex in the infected (live MDRSA and PRSC) tissue of the rats was almost five fold than in the inflamed and normal tissue. The high radiochemical stability in normal saline at room temperature, promising in-vitro stability in serum at 37 °C, saturated in-vitro binding with living MDRSA and PRSC, specific biodistribution behavior and high infected (target) to normal (non-target) tissue and low inflamed (non-target) to normal (non-target) tissue ratios we recommend ^99mTc–GXN complex for in-vivo localization of infection caused by MDRSA and PRSC effective stains.     

<Superscript>99m</Superscript>TcN–gatifloxacin dithiocarbamate complex: a novel multi-drug-resistance <Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis> (MRSP) infection radiotracer

Gatifloxacin (GTN) was derivatized to its dithiocarbamate derivative and its radiolabeling with technetium-99m (^99mTc) using the [^99mTc≡N]²⁺ core was investigated. The appropriateness of the ^99mTcN–gatifloxacin dithiocarbamate (^99mTcN–GTND) complex as a potential multi-drug-resistance Streptococcus pneumoniae (MRSP) infection radiotracer was evaluated in terms of stability in saline, serum, in vitro binding with MRSP and biodistribution in artificially MRSP infected Male Wistar Rats (MWR). In saline the ^99mTcN–GTND complex showed more than 90% labeling yield up to 4 h with a maximum yield of 98.25 ± 0.20%, after reconstitution. In serum the ^99mTcN–GTND complex showed stability up to 16 h of incubation with the appearance of insignificant 15.95% undesirable side products. The ^99mTcN–GTND complex demonstrated saturated in vitro binding with MRSP with a maximum value of 75.50 ± 1.00% (at 90 min). In MWR model of group A, almost six times higher uptake of the labeled GTND was monitored in the muscle of MWR infected with live MRSP as compared to the inflamed and normal muscles. Based on the higher labeling yield in saline, in vitro stability in serum, saturated in vitro binding with live MRSP and promising biodistribution in MWR model we recommend ^99mTcN–gatifloxacin dithiocarbamate complex as a potential MRSP infection radiotracer.     

<Superscript>99m</Superscript>Tc production via the (<Emphasis Type="Italic">γ, n</Emphasis>) reaction on natural Mo

In this paper, cheap liquorice residue was used to prepare activated carbon (AC), thioacetamide (TAA) was used to modify the AC, and the adsorption experiments were conducted in the simulated acid radioactive wastewater with low uranium concentration to study the adsorption behavior and mechanism for uranium by TAA modified AC (TAA–AC). The removal efficiency by TAA–AC was 92.1–98.2% from the 1 mg L^?1 uranium solution at pH 2–6. The adsorption equilibrium data were well fitted by Dubinin–Radushkevich model, and the maximum adsorption capacity was estimated to be 340 mg g^?1. TAA–AC showed an enhanced selectivity for uranium in the presence of competitive ions. Furthermore, the adsorption experiments were conducted in the actual acid radioactive wastewater with low uranium concentration from an in situ leach uranium mine. The high adsorption rate (98.3%) and selectivity (K_d?=?3.78×10⁴ mL g^?1) for uranium were observed in the actual acid radioactive wastewater, and the adsorption rate was found to maintain 96.2% over six cycles of adsorption–desorption.     

Sol-Gel Synthesis and Properties of Y<Subscript>1–<Emphasis Type="Italic">x</Emphasis></Subscript>Ba<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>FeO<Subscript>3</Subscript> Nanocrystals

The sol-gel method was used to prepare Y_1–xBa_xFeO₃ (x = 0, 0.05, 0.1, 0.15, 0.2) nanocrystals. The influence of the dopant content on the particle size and magnetic properties of yttrium ferrite was examined.     

Fast evaluation of molecular auxiliary functions <Emphasis Type="Italic">A</Emphasis><Subscript>α</Subscript> and <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> by analytical relations

Analytical relations through the initial values are derived for the molecular auxiliary functions A _α (x) and B _n (x), where α =n+ɛ, 0⩽ ɛ < 1 and n=0,1,2,.... These relations are useful in the fast calculation of multicenter molecular integrals over integer and noninteger n Slater type orbitals. It is shown that the formulas obtained are numerically stable for all values of n,ɛ and x.PACS No: 31.15.+q, 31.20.EjAMS subject classification: 81-V55, 81-V45     

Study on the preparation and biological evaluation of <Superscript>99m</Superscript>Tc–gatifloxacin and <Superscript>99m</Superscript>Tc–cefepime complexes

The aim of this work is the development of new radiopharmaceuticals for imaging infection and inflammation in human. Gatifloxacin (fluoroquinolone derivative) and cefepime (cephalosporine derivative) are antibiotics used to treat bacterial infections were investigated to label with one of the most important radioactive isotopes (technetium-99m). The reaction parameters that affect the labeling yield such as substrate concentration, stannous chloride dihydrate concentration, pH of the reaction mixture, and reaction time were studied to optimize the labeling conditions. Maximum radiochemical yield of ^99mTc–gatifloxacin (90  ± 1.8%) complex was obtained by using 50 μg SnCl₂·2H₂O and 2.5 mg gatifloxacin at pH 10 while ^99mTc–cefepime was prepared at pH 8 with a maximum radiochemical yield of 98  ± 1.4% by adding ^99mTc to 5 mg cefepime in the presence of 50 μg SnCl₂·2H₂O. Biological distribution of ^99mTc–gatifloxacin and ^99mTc–cefepime was carried out in experimentally induced infection rats, in the left thigh, using Escherichia coli. Both thighs of the rats were dissected and counted and the ratio of bacterial infected thigh/contralateral thigh was then evaluated. T/NT for both ^99mTc–gatifloxacin and ^99mTc–cefepime was found to be 4.5  ± 0.3 and 8.4  ± 0.1, respectively, which was higher than that of the commercially available ^99mTc–ciprofloxacin. The abscess to normal muscle ratio indicated that ^99mTc–cefepime could be used for infection imaging. Besides, in vitro studies showed that ^99mTc–cefepime can differentiate between bacterial infection and sterile inflammation.     

Structure of (DMF)<Subscript>m</Subscript>(HCl)<Subscript>n</Subscript> complexes (<Emphasis Type="Italic">m</Emphasis>= 2, <Emphasis Type="Italic">n</Emphasis> = 3–4)

(DMF)₂(HCl)₃ and (DMF)₂(HCl)₄ heterocomplexes were studied for the first time in terms of the B3LYP/6-31++G(d, p) density functional calculation. The resulting data about their structure, stability, strength of intermolecular bonds, and degree of proton transfer in O...H...Cl bridges are compared with the results of a similar calculation fulfilled for (DMF)_m(HCl)_n clusters (m, n = 1–2) and with the experimental data on the structure and properties of acid-base complexes in DMF solutions of HCl. An extremely stable symmetrical cycle of four molecules — (DMF)₂(HCl)₂ — is assumed to be a structure-forming element of solution in the DMF-HCl system in the range of concentrations achievable under normal conditions. When [HCl]₀ > [DMF]₀, the “excess” hydrogen chloride molecules add to the chlorine atoms of this cycle, forming heterocomplexes with a branched structure. Addition of more HCl molecules to the (DMF)₂(HCl)₂ cycle appreciably increases the degree of proton transfer from acid to base molecule.     

Kinetics of thermal reaction HOCl ⇄ H(<Superscript>2</Superscript><Emphasis Type="Italic">S</Emphasis>) + OCl(<Emphasis Type="Italic">X</Emphasis><Superscript>2</Superscript>Π<Subscript><Emphasis Type="Italic">i</Emphasis></Subscript>) in gas phase

The kinetics of gas reaction \(HOCl\underset{{k_r }}{\overset{{k_f }}{\longleftrightarrow}}H(^2 S) + OCl(X^2 \Pi _i )\) was analyzed by the MP4 method. In the temperature range of 100–373 K the rate constants k _f and k _r and equilibrium constant K were changed from 1.10 × 10^?220 to 1.17 × 10^?52 s^?1, from 2.89 × 10^?16 to 1.68 × 10^?5s^?1 and from 3.80 × 10^?205 to 6.96 × 10^?48 respectively. In the above temperature range, the activation energy of the forward reaction (E _f) is 105.05 kcal/mol. In the same temperature interval there are two kinetic domains for the reverse reaction with activation energies (E _r1 = 5.53 kcal/mol when T is 100–273 K and E _r2 = 14.50 kcal/mol when T is 273–373 K, respectively.     

New “s<Emphasis Type="Italic">p</Emphasis><Superscript><Emphasis Type="Italic">2</Emphasis></Superscript>-bonded” carbanucleosides

By reaction of 2,3-dichloro-, 2,3,5-trichloro-, 2,5-dichloro-3-phenylsulfonyl-, 2-chloro-3-phenylsulfonyl-4,4-ethylenedioxycyclopent-2-en-1-ones with uracyl 3- and 2-uracyl derivatives were obtained of the corresponding chlorocyclopentenone.     

Derivatives of <Emphasis Type="Italic">closo</Emphasis>-decaborate anion [B<Subscript>10</Subscript>H<Subscript>10</Subscript>]<Superscript>2−</Superscript> with <Emphasis Type="Italic">exo</Emphasis>-polyhedral substituents

Methods of introducing functional groups into the [B₁₀H₁₀]²⁻ anion based on electrophilic, radical, or nucleophilic substitution for exo-polyhedral hydrogen atoms have been surveyed. Special attention has been focused on nucleophilic substitution reactions promoted by acids, including protonic acids, anhydrous hydrogen halides, metal halides, and carbocations. In addition, methods of tailored functionalization of the substituents in the cluster have been described.     

DFT study on oxidation of HS(CH<Subscript>2</Subscript>)<Subscript> <Emphasis Type="Italic">m</Emphasis> </Subscript>SH (<Emphasis Type="Italic">m</Emphasis> = 1–8) in oxidative desulfurization

Density functional theory was employed for calculation of HS(CH₂)_mSH (m = 1–8) and its derivatives at B3LYP method at 6-31++g (d,p) level. Using eigenvalues of LUMO and HOMO for HS(CH₂)_mSH, the standard electrode potentials were estimated by a stepwise multiple regression techniques (MLR), and obtained as E° = 1.500 + 7.167 × 10^–3 HOMO–0.229 LUMO with high correlation coefficients of 0.973 and F values of 43.973.     

Planar Four-Coordinate Carbon in Star-Like Perlithioannulenes C<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>Li<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> (<Emphasis Type="Italic">n</Emphasis> = 3–6)

The structure and stability of perlithioannulenes C _n Li _n (n = 3–6) were examined ab initio [MP2(full)/6-311+G**] and in terms of the density functional theory (B3LYP/6-311+G**). The systems with n = 3, 5, and 6 may be stabilized as planar star-like structures with bridging lithium atoms and hypercoordinate carbon atoms. Star-like structures are the most stable isomers of odd-numbered annulenes (n = 3, 5), while the most stable isomers of even-numbered annulenes (n = 4, 6) have less symmetric nonplanar structures.     

TiO<Subscript>2</Subscript>/TiO<Subscript>2−<Emphasis Type="Italic">x</Emphasis></Subscript>N<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript> nanocomposite and its acetaldehyde photodecomposition ability

Nitrogen-doped titania was coupled with the commercial titania nanoparticles by mechanical milling in liquid medium. The as-prepared nanocomposites (TiO₂/TiO_2−x N _y ) were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area, UV–Vis spectroscopy, chemiluminescence, and acetaldehyde decomposition activity techniques. When a small amount of nitrogen-doped titania was added into the commercial titania, higher intensity and longer lifetime of ¹O₂ was observed, and the photocatalytic activity was efficiently improved. The TiO_2−x N _y acts as the acceptor of photoinduced holes. The recombination of the electron-hole was effectively depressed by the heterogeneous electron transfer. This could be an effective way to obtain highly active photocatalysts.     

Synthesis and characterization of LiCo<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Fe<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>VO<Subscript>4</Subscript> prepared by a citric acid complex method

For the first time, a method involving a citric acid complex has been used to prepare Fe-doped LiCoVO₄. LiCoVO₄ has the inverse spinel structure and posses a high voltage of 4.3 V vs. metallic Li. A disadvantage of LiCoVO₄ is its poor electronic conductivity, which is enhanced by using an Fe dopant. The doping levels were between 2 and 10 mol% to increase the electrical conductivity of the material. The citric acid complex method enabled us to make small particles in the range 0.3–0.6 m. The structure and the electrochemical properties of these materials were studied using X-ray diffraction, thermal gravimetric analysis, scanning electron microscopy, cyclic voltammetry, and cycle tests.Presented at the 3rd International Meeting on Advanced Batteries and Accumulators, 16–20 June 2002, Brno, Czech Republic     

<Superscript>51</Superscript>V NMR in Mn<Subscript>2−2<Emphasis Type="Italic">x</Emphasis></Subscript>Ni<Subscript>2<Emphasis Type="Italic">x</Emphasis></Subscript>V<Subscript>2</Subscript>O<Subscript>7</Subscript> solid solutions

⁵¹V NMR, DTA, and thermogravimetric analysis are used to study the thermal behavior of a manganesenickel pyrovanadate complex Mn_2?2x Ni_2x V₂O₇. It is shown that the nature of ⁵¹V hyperfine interactions in manganese pyrovanadate and solid solutions based on its polymorphic modifications is specified by the structurally activated oxygen exchange with the gaseous phase.     

Synthesis of 20<Emphasis Type="Italic">S</Emphasis>-protopanaxadiol <Emphasis Type="Italic">β</Emphasis>-D-galactopyranosides

20S-Protopanaxadiol (3β,12β,20S-trihydroxydammar-24-ene) 3-, 12-, and 20-O-β-D-galactopyranosides were synthesized for the first time. Condensation of 12β-acetoxy-3β,20S-dihydroxydammar-24-ene (1) and 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosylbromide (α-acetobromogalactose) (2) under Koenigs–Knorr conditions with subsequent removal of the protecting groups resulted in regio- and stereoselective formation of 20S-protopanaxadiol 3-O-β-D-galactopyranoside, an analog of the natural ginsenoside Rh₂. Glycosylation of 12β,20S-dihydroxydammar-24-en-3-one (5) by 2 with subsequent treatment of the reaction products with NaBH₄ in isopropanol and deacetylation with NaOMe gave 20S-protopanaxadiol 12- and 20-O-β-Dgalactopyranosides.     

Magnetic properties of CuCr<Subscript>2–<Emphasis Type="Italic">х</Emphasis></Subscript>Sb<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Se<Subscript>4</Subscript> (<Emphasis Type="Italic">х</Emphasis> = 0–0.5) solid solutions

Magnetic properties of spinel solid solutions CuCr_2–х Sb _x Se₄ (х = 0–0.5) were measured in the temperature range 5–300 K in a constant (50 Oe and 10 kOe) magnetic field. The results are interpreted in terms of the ionic model suggested earlier for CuCr₂Х₄ compounds.