Rovibrational spectroscopy and intramolecular dynamics of 1,2-trans-d(2)-ethene in the first C-H stretch overtone region

The first overtone region of the C-H stretching vibration of 1,2-trans-d(2)-ethene (HDC=CDH) was monitored via jet-cooled action spectroscopy and room temperature photoacoustic spectroscopy. The spectra include a strong band, which we assigned as the nu(1)+nu(9) C-H stretch vibration, and five additional bands related to transitions to coupled states. The spectral features were modeled in terms of a six-state deperturbation analysis, revealing the energies of the zero-order states and the relatively strong couplings between the initially excited nu(1)+nu(9) state and the doorway states. Considering these energies and the fundamental frequencies of 1,2-trans-d(2)-ethene and presuming that only low-order resonances are involved in the couplings enabled the assignment of the states. The analysis also allowed obtaining insight on energy flow and to find out that the energy oscillations between the C-H stretch state and the doorway states occur on a subpicosecond time scale.     

Therapeutic target metabolism observed using hyperpolarized 15N choline

Choline is a precursor of cellular phospholipid metabolism that provides Magnetic Resonance (MR) and Positron Emission Tomography (PET) biomarkers for cancer detection and response assessment. Employing Dynamic Nuclear Polarization we show that the MR signal of 15N in choline can be enhanced by at least 4 orders of magnitude with a relaxation time of ca. 4 min, providing a method to observe the action of choline kinase, an important target for novel cancer therapeutics.     

Disinfection and Mechanistic Insights of Escherichia coli in Water by Bismuth Oxyhalide Photocatalysis

This study demonstrates the potential of a new BiOCl_0.875Br_0.125 photocatalyst to disinfect Escherichia coli in water under simulated solar irradiation. Photocatalytic efficiency was examined for different photocatalyst loadings, solar wavelengths, exposure times, photocatalyst concentration × contact time (Ct) concept and with the use of scavengers. To elucidate the inactivation mechanism, we examined DNA damage, membrane damage, lipid peroxidation and protein release. Both photolysis and photocatalysis were negligible under visible irradiation, but enhanced photocatalytic activity was observed under solar UVA (λ > 320 nm) and UVB (λ > 280 nm), with 1.5 and 3.6 log inactivation, respectively, after 40 min of irradiation. The log inactivation vs Ct curve for E. coli by UVA/BiOCl_0.875Br_0.125 was fairly linear, with Ct = 10 g L^?1 × min, resulting in 2 log inactivation. Photocatalytic treatment led to membrane damage, but without lipid peroxidation. Accordingly, protein was released from the cells after UVA or UVA/BiOCl_0.875Br_0.125 treatment. Photocatalysis also increased endonuclease‐sensitive sites vs photolysis alone, by an unknown mechanism. Finally, E. coli inactivation was not influenced by the addition of tert‐butanol or l ‐histidine, implying that neither hydroxyl radicals nor singlet oxygen reactive species are involved in the inactivation process.     

Disruption of the hexagonal networks of trimesic acid (benzene-1,3,5-tricarboxylic acid, TMA) by acetic acid

The single crystal X-ray structure of the acetic acid solvate of trimesic acid shows the complete disruption of the hydrogen-bonded hexagonal networks of TMA by bonding to an acetic acid molecule.     

Cut-Free Ordinary Sequent Calculi for Logics Having Generalized Finite-Valued Semantics

The paper presents a method for transforming a given sound and complete n-sequent proof system into an equivalent sound and complete system of ordinary sequents. The method is applicable to a large, central class of (generalized) finite-valued logics with the language satisfying a certain minimal expressiveness condition. The expressiveness condition decrees that the truth-value of any formula φ must be identifiable by determining whether certain formulas uniformly constructed from φ have designated values or not. The transformation preserves the general structure of proofs in the original calculus in a way ensuring preservation of the weak cut elimination theorem under the transformation. The described transformation metod is illustrated on several concrete examples of many-valued logics, including a new application to information sources logics.     

Vibrationally mediated photodissociation of ethene isotopic variants preexcited to the fourth C-H stretch overtone

H and D photofragments produced via vibrationally mediated photodissociation of jet-cooled normal ethene (C2H4), 1,2-trans-d2-ethene (HDCCDH), and 1,1-d2-ethene (CH2CD2), initially excited to the fourth C-H stretch overtone region, were studied for the first time. H and D vibrational action spectra and Doppler profiles were measured. The action spectra include partially resolved features due to rotational cooling, while the monitored room temperature photoacoustic spectra exhibit only a very broad feature in each species. Simulation of the spectral contours allowed determination of the band types and origins, limited precision rotational constants, and linewidths, providing time scales for energy redistribution. The H and D Doppler profiles correspond to low average translational energies and show slight preferential C-H over C-D bond cleavage in the deuterated variants. The propensities toward H photofragments emerge even though the energy flow out of the initially prepared C-H stretch is on a picosecond time scale and the photodissociation occurs following internal conversion, indicating a more effective release of the light H atoms.     

Ladder oligo(m-aniline)s: derivatives of azaacenes with cross-conjugated π-systems

We describe the synthesis and electronic properties of ladder oligomers of poly(m-aniline) that may be considered as derivatives of azaacenes with cross-conjugated π-systems. Syntheses of ladder oligo(m-aniline)s with 9 and 13 collinearly fused six-membered rings employed Pd-catalyzed aminations and Friedel-Crafts-based ring closures. Structures were confirmed by either X-ray crystallography or correlations between DFT-computed and experimental spectroscopic data such as (1)H, (13)C, and (15)N NMR chemical shifts and electronic absorption spectra. All compounds have planar "azaacene" moieties. The experimental band gaps E(g) ≈ 3.5-3.65 eV, determined by the UV-vis absorption onsets, were in agreement with the TD-DFT-computed vertical excitation energies to the S(1) state. Fluorescence quantum yields of up to 20% were found. Electrochemically estimated HOMO energies of -4.8 eV suggested propensity for a facile one-electron oxidation and just sufficient environmental stability toward oxygen (O(2)). For two oligomers with "tetraazanonacene" moieties, potentials of E(4+/3+) ≈ 1.6-1.7 V vs SCE were determined for four-electron oxidation to the corresponding tetraradical tetracations.     

Thermogravimetry analysis,compressive strength and thermal conductivity tests of non-autoclaved aerated Portland cement–fly ash–silica fume concrete

Journal of Thermal Analysis and Calorimetry - This paper reports the investigated thermogravimetry analysis, compressive strength and thermal conductivity tests of non-autoclaved aerated Portland...