Phosphorescent Ruthenium Complexes with a Nitroimidazole Unit that Image Oxygen Fluctuation in Tumor Tissue

Understanding oxygen fluctuation in a cancerous tumor is important for effective treatment, especially during radiotherapy. In this paper, ruthenium complexes bearing a nitroimidazole group are shown to report the oxygen status in tumor tissue directly. The nitroimidazole group was known to be accumulated in hypoxic tumor tissues. On the other hand, the ruthenium complex showed strong phosphorescence around 600 nm. The emission of ruthenium is quenched instantaneously by molecular oxygen due to energy transfer between triplet states of oxygen and ruthenium complex, but the emission is then recovered by the removal of oxygen. Thus, we could observe oxygen fluctuation in tumor tissue in a real‐time manner by monitoring the phosphorescence of the ruthenium complex. The versatility of the probe is demonstrated by monitoring oxygen fluctuation in living cells and tumor tissue planted in mice. The ruthenium complex promptly penetrated plasma membrane and accumulated in cells to emit its oxygen‐dependent phosphorescence. In vivo experiments revealed that the oxygen level in tumor tissue seems to fluctuate at the sub‐minute timescale.     

Residual stresses and warp generated by one-sided quench of an epoxy-resin beam

This paper discusses the warp and accompanying residual stress in a rectangular epoxy beam produced by water cooling its lower surface. First, the theoretical values of this warp and residual stress are obtained by the linear-viscoelastic theory. The specimen is then subjected to quenching. The variations in the warp are observed. After quenching, the residual stress is measured by a layer-removal method. The experimental and theoretical results are then compared and discussed.     

Validated method using liquid chromatography-electrospray ionization tandem mass spectrometry for the determination of contamination of the exterior surface of vials containing platinum anticancer drugs

Contamination of the exterior surface of vials of cytostatic drugs by the drugs themselves is a potential hazard to human health. This study developed a validated method using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the determination of contamination of the exteriors of vials of cisplatin and carboplatin. Large Alpha^® sampling swabs were employed to wipe the vial exterior. Cisplatin or carboplatin and gold(III) as an internal standard were derivatized by N,N-diethyldithiocarbamate (DDTC). Pt(DDTC)₃⁺ and Au(DDTC)₂⁺ were monitored by the respective transitions of m/z 639.3-490.9 and 493.0-345.0, respectively. Each separation was completed within 9 min using a 3 μm particle ODS-column. Calibration curves for cisplatin and carboplatin were linear over concentration ranges of 30-10,000 and 30-30,000 pg vial⁻¹, respectively. The accuracies and precisions were 96.1-102.5% and within 8.2% for intra-assay and 99.6-103.3% and within 7.6% for inter-assay, respectively. Their lower limit of quantification was 30 pg vial⁻¹. Amounts of 0.17-17.0 ng vial⁻¹ as cisplatin and 0.48-794 ng vial⁻¹ as carboplatin were detected from the exterior surface of the vials. This validated method using LC-ESI-MS/MS for the determination of platinum anticancer drugs is helpful for monitoring contamination of the exterior surface of drug vials.     

A-type cranberry proanthocyanidins inhibit the RANKL-dependent differentiation and function of human osteoclasts

This study investigated the effect of A-type cranberry proanthocyanidins (AC-PACs) on osteoclast formation and bone resorption activity. The differentiation of human pre-osteoclastic cells was assessed by tartrate-resistant acid phosphatase (TRAP) staining, while the secretion of interleukin-8 (IL-8) and matrix metalloproteinases (MMPs) was measured by ELISA. Bone resorption activity was investigated by using a human bone plate coupled with an immunoassay that detected the release of collagen helical peptides. AC-PACs up to 100 μg/mL were atoxic for osteoclastic cells. TRAP staining evidenced a dose-dependent inhibition of osteoclastogenesis. More specifically, AC-PACs at 50 μg/mL caused a 95% inhibition of RANKL-dependent osteoclast differentiation. This concentration of AC-PACs also significantly increased the secretion of IL-8 (6-fold) and inhibited the secretion of both MMP-2 and MMP-9. Lastly, AC-PACs (10, 25, 50 and 100 μg/ml) affected bone degradation mediated by mature osteoclasts by significantly decreasing the release of collagen helical peptides. This study suggests that AC-PACs can interfere with osteoclastic cell maturation and physiology as well as prevent bone resorption. These compounds may be considered as therapeutic agents for the prevention and treatment of periodontitis.     

Determination of cyanide in blood by electrospray ionization tandem mass spectrometry after direct injection of dicyanogold

An electrospray ionization tandem mass spectrometric (ESI-MS-MS) method has been developed for the determination of cyanide (CN^–) in blood. Five microliters of blood was hemolyzed with 50 μL of water, then 5 μL of 1 M tetramethylammonium hydroxide solution was added to raise the pH of the hemolysate and to liberate CN^– from methemoglobin. CN^– was then reacted with NaAuCl₄ to produce dicyanogold, Au(CN)₂^–, that was extracted with 75 μL of methyl isobutyl ketone. Ten microliters of the extract was injected directly into an ESI-MS-MS instrument and quantification of CN^– was performed by selected reaction monitoring of the product ion CN^– at m/z 26, derived from the precursor ion Au(CN)₂^– at m/z 249. CN^– could be measured in the quantification range of 2.60 to 260 μg/L with the limit of detection at 0.56 μg/L in blood. This method was applied to the analysis of clinical samples and the concentrations of CN^– in the blood were as follows: 7.13 ± 2.41 μg/L for six healthy non-smokers, 3.08 ± 1.12 μg/L for six CO gas victims, 730 ± 867 μg for 21 house fire victims, and 3,030 ± 97 μg/L for a victim who ingested NaCN. The increase of CN^– in the blood of a victim who ingested NaN₃ was confirmed using MS-MS for the first time, and the concentrations of CN^– in the blood, gastric content and urine were 78.5 ± 5.5, 11.8 ± 0.5, and 11.4 ± 0.8 μg/L, respectively.     

Exchange interactions in a trigonal chromium (III) pair

The theory of exchange interactions in the excited state of a trigonal chromium(III) pair which occurs in Cs₃Cr₂Cl₉, and first nearest neighbours in ruby, is extended to the singly excited ² T ₁, ² T ₂ and ² E(t ₂ ³) pair states. The multiplet splitting is described by an effective hamiltonian which includes trigonal field, spin-orbit coupling, first-order Zeeman effect and bilinear and biquadratic exchange. Previous calculations on the important single-ion intensity mechanism for ² E pair states are incorrect. The corrected electric dipoles for ² E and also for ² T ₁ and ² T ₂ pair states are presented.     

Laser-induced periodic surface structures formed on the sidewalls of microholes trepanned by a femtosecond laser

Laser-induced periodic surface structures (LIPSSs) were observed on the sidewalls of 300-μm-diameter holes trepanned on cemented tungsten carbide using femtosecond laser pulses at a wavelength of 800 nm. For a circularly polarized beam, LIPSSs were formed at a period of 300 nm and oriented perpendicularly to the plane of incidence on the sidewalls. For a linearly polarized beam, LIPSS formation was dependent on the relative angle α between the polarization direction and the plane of incidence. For relative angles α from 0° to 70° and from 110° to 180°, LIPSS spacing was 300 nm. However, there were two types of LIPSSs coexisting from 70° to 110°. One had a spacing of 120 nm and the other had a spacing that varied from 500 to 760 nm. It was found that the orientation angle of LIPSSs measured between the LIPSS orientation and the plane of incidence had a nonlinear dependence on α. To understand this dependence, a model was proposed in which LIPSSs are assumed to align perpendicularly to the direction of the absorbed electric field lying in the tangent plane of the sidewall of a drilled hole. The calculated results from this model showed good agreement with the experimental results.     

Palladium-catalyzed stereospecific 1,4-hydrogen migration of cis-cyclohex-2-en-1,4-diol systems

It has been revealed that the generation of 2-cyclohexenones from cis-1,4-dihydroxycyclohexene derivatives under PdCl₂(PPh₃)₂-HCO₂NH₄ system takes place in an intramolecular pathway involving unprecedented mode of suprafacial 1,4-hydrogen migration across the 1,4-allylic centers.     

Utilization of gamma-ray irradiation for hydrogen production from water

A technique has been proposed to promote hydrogen production from water by increasing the energy deposition in water through the conversion of γ-ray to low-energy electrons, which is achieved by putting solid materials into water. Simulation studies by the MCNP code indicate that the average deposited energy in water can be increased by optimizing geometry of the materials. In the present experiments using Al₂O₃ particles of various average diameters, the maximum amount of hydrogen produced is 3.48 μmol/cm³ for the water containing Al₂O₃ particles of 3 μm diameter, which is more than two order of magnitude larger of the H₂ produced in water-only configuration.     

Determination of tin by resin-suspension electrothermal atomic absorption spectrometry after enrichment as the complex with ammonium pyrrolidinedithiocarbamate.

A resin-phase extraction method has been optimized for the trace determination of tin(II) by ETAAS. Tin(II) was extracted on a finely divided anion exchange resin as the complex with ammonium pyrrolidinedithiocarbamate (APDC). The resin was collected on a membrane filter and then dispersed in 1.00 ml of 1 mol l(-1) nitric acid containing 100 microg of Pd(II) and 60 microg of Ni(II). The resulting resin suspension was subjected to GFAAS. The proposed method was applied to the determination of tin(II) in hydrochloric acid.