Validation of the Metabolite Ergothioneine as a Forensic Marker in Bloodstains

Ergothioneine, which is a naturally occurring metabolite, generally accumulates in tissues and cells subjected to oxidative stress, owing to its structural stability at physiological pH; therefore, it has been attracting attention in various biomedical fields. Ergothioneine has also been suggested as a potential forensic marker, but its applicability has not yet been quantitatively validated. In this study, quantitative analysis of ergothioneine in bloodstains was conducted to estimate the age of bloodstains and that of bloodstain donors. Blood from youth and elderly participants was used to generate bloodstains. After extracting metabolites from the bloodstains under prevalent age conditions, ergothioneine levels were quantified by mass spectrometry via multiple reaction monitoring. The concentration of ergothioneine in day 0 bloodstains (fresh blood), was significantly higher in the elderly group than in the youth group, but it did not differ by sex. Statistically significant differences were observed between the samples from the two age groups on days 0, 5 and 7, and on days 2 and 3 compared with day 0. The findings suggest that ergothioneine can be used to estimate the age of bloodstains and of the donor; it could be useful as a potential marker in reconstructing crime scenes.     

Medicarpin and Homopterocarpin Isolated from Canavalia lineata as Potent and Competitive Reversible Inhibitors of Human Monoamine Oxidase-B

Thirteen compounds were isolated from the Canavalia lineata pods and their inhibitory activities against human monoamine oxidase-A (hMAO-A) and -B (hMAO-B) were evaluated. Among them, compounds 8 (medicarpin) and 13 (homopterocarpin) showed potent inhibitory activity against hMAO-B (IC₅₀ = 0.45 and 0.72 µM, respectively) with selectivity index (SI) values of 44.2 and 2.07, respectively. Most of the compounds weakly inhibited MAO-A, except 9 (prunetin) and 13. Compounds 8 and 13 were reversible competitive inhibitors against hMAO-B (K_i = 0.27 and 0.21 µM, respectively). Structurally, the 3-OH group at A-ring of 8 showed higher hMAO-B inhibitory activity than 3-OCH3 group at the A-ring of 13. However, the 9-OCH3 group at B-ring of 13 showed higher hMAO-B inhibitory activity than 8,9-methylenedioxygroup at the B-ring of 12 (pterocarpin). In cytotoxicity study, 8 and 13 showed non-toxicity to the normal (MDCK) and cancer (HL-60) cells and moderate toxicity to neuroblastoma (SH-SY5Y) cell. Molecular docking simulation revealed that the binding affinities of 8 and 13 for hMAO-B (−8.7 and −7.7 kcal/mol, respectively) were higher than those for hMAO-A (−3.4 and −7.1 kcal/mol, respectively). These findings suggest that compounds 8 and 13 be considered potent reversible hMAO-B inhibitors to be used for the treatment of neurological disorders.     

Analyse qualitative et détermination colorimétrique du cobalt au moyen de la carboxy-2-isonitrosoacétanilide

A new method for the identification and colorimetric estimation of Co(II) with 2-carboxy-isonitrosoacetanilide has been developed. This reagent is specific and its sensitiviness is D = 10^b-6(1:1,000,000). The best possible conditions are indicated for the colorimetric determination whereby Beer's law holds for dilutions to 1,2:1,000,000.     

Continuous and pulsed quantum zeno effect

Continuous and pulsed quantum Zeno effects were observed using a 87Rb Bose-Einstein condensate. Oscillations between two ground hyperfine states of a magnetically trapped condensate, externally driven at a transition rate omega(R), were suppressed by destructively measuring the population in one of the states with resonant light. The suppression of the transition rate in the two-level system was quantified for pulsed measurements with a time interval deltat between pulses and continuous measurements with a scattering rate gamma. We observe that the continuous measurements exhibit the same suppression in the transition rate as the pulsed measurements when gammadeltat=3.60(0.43), in agreement with the predicted value of 4. Increasing the measurement rate suppressed the transition rate down to 0.005 omega(R).     

Parametric amplification of scattered atom pairs

We have observed parametric generation and amplification of ultracold atom pairs. A 87Rb Bose-Einstein condensate was loaded into a one-dimensional optical lattice with quasimomentum k0 and spontaneously scattered into two final states with quasimomenta k1 and k2 . Furthermore, when a seed of atoms was first created with quasimomentum k1 we observed parametric amplification of scattered atoms pairs in states k1 and k2 when the phase-matching condition was fulfilled. This process is analogous to optical parametric generation and amplification of photons and could be used to efficiently create entangled pairs of atoms. Furthermore, these results explain the dynamic instability of condensates in moving lattices observed in recent experiments.     

Strong and stable red photoluminescence from porous silicon prepared by Fe-contaminated silicon

Strong red photoluminescence (PL) spectra appeared at porous silicon (PS) samples prepared by a chemical anodization of Fe-contaminated Si substrates. The Fe1000 sample with Fe contamination of 1000 ppb showed a ten times stronger red PL than that of the reference PS sample without any Fe contamination, and this sample also showed the higher thermal stability for PL spectra as compared with the reference PS sample. Furthermore, the PL intensity from the PS with Fe contamination is linearly proportional to the Fe-related trap concentrations of Si substrates obtained from DLTS. Especially, all the PS samples exhibit the same PL peak position regardless of Fe contamination concentrations, as compared with that of the reference PS. This means that there is no significant effect such as the variation of size distribution of nanocrystalline Si in PS layer formed on Fe-contaminated Si substrate. Based on the results of PL and DLTS, we found that the PL efficiency depends strongly on the Fe-related trap concentration in Si substrates.     

Detection of protein deposits using NIR spectroscopy

The aim of this study was to determine if it is possible to distinguish between the groups of spoiled and unspoiled soft contact lenses using near-infrared spectroscopy and new analytical approach – Aquaphotomics. Using the principal component analysis, it was established that the absorbance spectra of worn and new contact lenses are differed at water absorption band related to hydration of proteins. Detection of proteins thus was performed indirectly by using vibrations of water molecules. This exploratory study showed that near-infrared spectroscopy and Aquaphotomics have potential for non-invasive, chemical-free detection of protein deposits on hydrated soft contact lenses.     

Improving precursor adsorption characteristics in ATR-FTIR spectroscopy with a ZrO2 nanoparticle coating

Journal of Nanoparticle Research - Transparent superhydrophobic coatings, which are highly desired for the protection of material surfaces, have been limited to particular kinds of materials, e.g....     

Characterization of wafer-scale MoS2 and WSe2 2D films by spectroscopic ellipsometry

Here, we present the spectroscopic ellipsometry investigation of synthetically grown wafer-scale two-dimensional (2D) MoS₂ and WSe₂ films to access quality and thickness uniformity. MoS₂ and WSe₂ samples were grown by chemical vapor deposition and atomic layer deposition, respectively. Complex dielectric function ($\epsilon ={\epsilon }_1+i{\epsilon }_2$) and thickness information of these 2D films were extracted from the measured data using multilayer optical calculations. Broad spectral range (1.2–6 eV) and multiple angles of incidence were used to reduce correlations among fitting parameter. Lineshape of ε of MoS₂ and WSe₂ monolayer films are consistent with literature but shows higher values, suggests better quality of our samples. Eight-inch wafer size MoS₂ monolayer sample shows ～ 70% uniformity with an average thickness of 0.65 ± 0.2 nm, and three-layer WSe₂ sample of 8 × 1 cm² area shows ～ 80% uniformity with an average thickness of 2.5 ± 0.4 nm. Our results will be helpful to accelerate commercialization process of 2D devices.