FT-FIR-spectrum and the ground state constants of D2CO

The ground state spectrum of the formaldehyde D₂¹³CO molecule in the range from 25 to 360 cm⁻¹ has been recorded by a Fourier transform infrared spectrometer. The quantum number limits of the assigned transitions are J = 6-54 and K_a = 0-16. The data was fitted into Watson’s A- and S-reduced Hamiltonians in I^r-representation up to eighth order. The determinable constants calculated from both reductions are compared. The standard deviation of the far infrared data is 3.0 MHz. The spectroscopic constants are also calculated to high accuracy at the CCSD(T)/cc-pVQZ level of ab initio theory and agree well with the experimental ones.     

Photon collider beam simulation with CAIN

The CAIN simulation program was used to study the outgoing beam profile for the photon collider at ILC. The main aim of the analysis was to verify the feasibility of the photon linear collider running with 20 mrad electron beam crossing angle. The main problem is the distorted electron beam, which has to be removed from the interaction region. It is shown that with a new design of the final dipole, it should be possible to avoid large energy losses at the face of the magnet.      

Phenylalanine‐Derived Imidazolines Bearing Heteroaromatic Pendants: Synthesis,Characterization, and Application in the Asymmetric Henry Reaction

Starting from L ‐phenylalanine, (2S)‐3‐phenylpropane‐1,2‐diamine has been prepared and used as building block for the construction of the imidazoline ring. Four new optically pure NH‐imidazolines bearing different six‐membered heteroaromatic substituents on the C(2) position have been prepared and subsequently N‐modified. N‐Substitution afforded two regioisomers that were separated. Some of them proved to be instable and hydrolyzed to diamides. The molecular structures of NH‐imidazolines, both N‐substituted regioisomers, as well as diamides, were unambiguously confirmed by X‐ray‐analysis and NMR spectra. The successfully prepared imidazolines, as well as diamides, were applied as catalysts in a Cu(II)‐catalyzed Henry reaction achieving 26–98% chemical yields and enantiomeric excesses of 3–42%.     

Interfacing of microbial cells with nanoparticles: Simple and cost-effective preparation of a highly sensitive microbial ethanol biosensor

Various types of carbon nanoparticles were directly mixed with microbial cells of Gluconobacter oxydans within a 3-D bionanocomposite in order to prepare a highly sensitive ethanol biosensor with a short response time. From all carbonaceous nanomaterials tested, single- or multi-walled carbon nanotubes provided the highest sensitivity of detection (117–121 µA cm^?2 mM^?1), but from a practical point of view, Ketjen black 300 and 600 provide very low detection limit (2–6 µM) and high sensitivity for the ethanol analysis (84–88 µA cm^?2 mM^?1)with a shortresponse time (14–33 s). Moreover, the price of Ketjen black is a few orders of magnitude lower compared to that of carbon nanotubes. Finally, the study showed that the morphology of nanoparticles rather than their surface modification is the key element in achieving high sensitivity of ethanol detection.     

<Emphasis Type="Italic">Gluconobacter</Emphasis> sp. cells for manufacturing of effective electrochemical biosensors and biofuel cells

Gluconobacter oxydans bacteria exhibit a unique metabolism for quick and incomplete oxidation of a wide range of different compounds (aldoses, ketoses, mono- and poly-alcohols, etc.). Such biotransformation efficiency with simple biomass production led to the industrial applications of these bacteria in the production of several important commodities. Their respiratory activity can also be successfully studied and used in the field of bioelectrochemistry. The main aim of this review is to present various strategies to improve selectivity of assays using intact/treated cells of G. oxydans, to introduce the application of G. oxydans-based biosensors in selective monitoring of analytes during biotransformation processes and to provide information about utilizable sugars in fermentation media or in biological oxygen demand value determination. The final part of the review describes potential application of G. oxydans cells in the generation of electricity from complex fuels within microbial fuel cells by advanced direct electron transfer route between bacterial cells and electrodes.     

Single‐Crystal‐to‐Single‐Crystal Transition in an Enantiopure [7]Helquat Salt: The First Observation of a Reversible Phase Transition in a Helicene‐Like Compound

Here it is reported that crystals of an enantiopure [7]helquat salt undergo reversible thermal solid–solid phase transition at 404 K. Differential scanning calorimetry (DSC), capillary electrophoresis (CE), and X‐ray diffraction analysis were used to unravel the mechanistic details of this process. The single‐crystal‐to‐single‐crystal course enabled direct monitoring of the structural changes by in situ variable‐temperature X‐ray diffraction, thus providing the first direct evidence of a solid phase transition in a helicene‐like compound.     

Development and validation of high-performance thin-layer chromatographic method for determination of amygdalin

ABSTRACT

A new method for the extraction and quantitative determination of amygdalin has been proposed. Accelerated solvent extraction was applied for the extraction, and reversed-phase high-performance thin-layer chromatography method was developed, validated, and applied for the determination of amygdalin in the extracts of apricot, plum, almond, and peach kernels. The chromatographic system used was RP-18 silica, as stationary phase and acetonitrile/water (50:50, v/v), as mobile phase. Densitometric scanning was performed at 210 nm. The method was validated with respect to specificity, linearity, precision, and accuracy. The results showed that the peak area responses were linear within the concentration range of 2.5–50.0 µg/spot (R² = 0.9984). The limit of quantification was 4.28 µg/spot, and the detection limit 1.28 µg/spot. The intra-day and inter-day reproducibility, in terms of %RSD, were in the range of 0.81–1.15 and 1.32–1.89, respectively. The accuracy data were in the range from 99.98 to 100.56%. The method is linear, quantitative and reproducible, and could be used as an efficient and economical green chromatographic procedure for the determination of amygdalin in the fruit kernel.     

Minimal Projections onto Subspaces with Codimension 2

In this article, the relationship between absolute projection constants with dimension n and with codimension n is given. In particular, bounds from below are found for absolute projection constants with codimension 2. Also, exact formulas for minimal projections in this case are given. It is shown that these minimal projections are not unique.     

Cycloaddition Reactions of Deoxyribosylpropynoates

Pure anomers of either α or β 3-(2-deoxyribofuranosyl)propynoates reacted with the tetramethylcyclobutadiene–aluminum trichloride complex to yield the corresponding diastereoisomeric Dewar benzenes. Thermal- or ultraviolet light–initiated rearrangement gave rise to highly substituted C-aryldeoxyribosides as single anomers. The same compounds as well as other substituted deoxyribosides were obtained also by transition metal–mediated cycloaddition reactions.