Sensitivities of some imidazole-1-sulfonyl azide salts

Imidazole-1-sulfonyl azide hydrochloride, an inexpensive and effective diazotransfer reagent, was recently found to be impact sensitive. To identify safer-to-handle forms of this reagent, several different salts of imidazole-1-sulfonyl azide were prepared, and their sensitivity to heat, impact, friction, and electrostatic discharge was quantitatively determined. A number of these salts exhibited improved properties and can be considered safer than the aforementioned hydrochloride. The solid-state structures of the chloride and less sensitive hydrogen sulfate were determined by single-crystal X-ray diffraction in an effort to provide some insight into the different properties of the materials.     

Magnetic resonance study of carbon encapsulated Ni nanoparticles

Magnetic resonance study of six samples consisting of carbon encapsulated nickel nanoparticles or carbon nanotubes ended with such nickel nanoparticles was carried out at room temperature. Samples of Ni/C were prepared by carburization of nanocrystalline nickel by ethylene (C₂H₄) and methane (CH₄). Hydrocarbons decomposition on nickel nanoparticles was done at temperatures 500, 600 and 700°C. Magnetic resonance spectra of samples designated as CH₄/500, CH₄/600, CH₄/700, C₂H₄/500, C₂H₄/600 and C₂H₄/700 were obtained by Bruker E 500 spectrometer. The integrated intensities of the resonance spectra were correlated with the carburization conditions (temperature, type of hydrocarbon) during samples preparation. A core-shell model of the investigated samples allowed rough estimation of appropriate shell sizes.      

Could X-Ray Analysis Explain for the Differing Antimicrobial and Antioxidant Activity of Two 2-Arylamino-3-Nitro-Coumarins?

Abstract  

X-Ray analyses of 4-(naphthalen-1-ylamino)-3-nitro-chromen-2-one and 3-nitro-4-phenylamino-chromen-2-one showed that the mentioned compounds crystallize in the space groups P1- (triclinic crystal system; unit cell parameters: a = 8.087(2) ?, b = 9.241(3) ?, c = 10.911(3) ?, α = 93.77(3)°, β = 102.51(3)°, γ = 106.44(2)°, V = 756.4(4) ?³ and Z = 2) and P2₁2₁2₁ (orthorhombic crystal system; unit cell parameters: a = 4.9274(9) ?, b = 14.725(3) ?, c = 17.866(4) ?, α = β = γ = 90°, V = 1296.3(5) ?³ and Z = 4), respectively. The analyses of crystal structures and gas phase conformations, inferred from single X-ray crystallographic and molecular modeling experiments, respectively, showed that the changes in π delocalization of the farmacoactive formal 3-amino-2-nitro-acrylic acid derivatives might explain the observed significant difference of the antimicrobial and antioxidant activities and spectral properties of two 4-arylamino-3-nitro-coumarin derivatives.     

Numerical values of the electrokinetic potentials of anatase at high concentration of NaI

The electrokinetic potential of anatase (titanium dioxide) in 0.3, 0.5, and 1 mol dm(-3) NaI was studied by means of AcoustoSizer 1, AcoustoSizer 2 and DT-1200. Different stirring modes were studied for DT-1200. The increase in the electrolyte concentration produced a shift in the IEP of anatase to higher pH, and for 1 mol dm(-3) NaI there was no IEP at all, and the electrokinetic potential was positive over the entire pH range. The shifts in the IEP observed by means of different instruments were qualitatively consistent. On the other hand, the numerical values of the electrokinetic potentials of anatase at high concentration of NaI at low pH obtained by means of Acoustosizer 2 were substantially higher than those obtained by means of DT-1200. The discrepancies in the numerical values of the electrokinetic potentials obtained by means of different instruments increase as the ionic strength increases. The procedure of correction for the electroacoustic signal of the electrolyte is probably the main source of the discrepancies between DT-1200 and Acoustosizer at high ionic strengths. The difference in the efficiency of mixing in different stirring modes plays rather insignificant role in the observed discrepancies.     

Vocal Behavior and Vocal Loading Factors for Preschool Teachers at Work Studied with Binaural DAT Recordings

Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices.     

Optical absorption in discontinuous gold films

Discontinuous gold films with mass thicknesses 1.1–4.0nm were prepared by UHV-deposition onto glass substrates. The islands were accurately represented by randomly oriented prolate spheroids (symmetry axis parallel with substrate plane) with varying sizes and eccentricities. Optical transmittance was recorded for wavelengths 0.3–2.5μm. Extensive computations, based on the Maxwell-Garnett formalism, were carried out for islands surrounded by air. The calculated transmittances were much larger than the experimental ones. The most likely explanation is that local field effects are more prominent than estimated from recent theories.     

A Rapid,Amplification‐Free,and Sensitive Diagnostic Assay for Single‐Step Multiplexed Fluorescence Detection of MicroRNA

The importance of microRNA (miRNA) dysregulation for the development and progression of diseases and the discovery of stable miRNAs in peripheral blood have made these short‐sequence nucleic acids next‐generation biomarkers. Here we present a fully homogeneous multiplexed miRNA FRET assay that combines careful biophotonic design with various RNA hybridization and ligation steps. The single‐step, single‐temperature, and amplification‐free assay provides a unique combination of performance parameters compared to state‐of‐the‐art miRNA detection technologies. Precise multiplexed quantification of miRNA‐20a, ‐20b, and ‐21 at concentrations between 0.05 and 0.5 nM in a single 150 μL sample and detection limits between 0.2 and 0.9 nM in 7.5 μL serum samples demonstrate the feasibility of both high‐throughput and point‐of‐care clinical diagnostics.