Isobaric vapor–liquid equilibria for binary systems α-phenylethylamine + toluene and α-phenylethylamine + cyclohexane at 100 kPa

In this paper the results of the vapor–liquid equilibria study at 100 kPa are presented for two binary systems: α-phenylethylamine(1) + toluene (2) and (α-phenylethylamine(1) + cyclohexane(2)). The binary VLE data of the two systems were correlated by the Wilson, NRTL, and UNIQUAC models. For each binary system the deviations between the results of the correlations and the experimental data have been calculated. For the both binary systems the average relative deviations in temperature for the three models were lower than 0.99%. The average absolute deviations in vapour phase composition (mole fractions) and in temperature T were lower than 0.0271 and 1.93 K, respectively. Thermodynamic consistency has been tested for all vapor-liquid equilibrium data by the Herrington method. The values calculated by Wilson and NRTL equations satisfied the thermodynamics consistency test for the both two systems, while the values calculated by UNIQUAC equation didn’t.     

Kinetics of the Antibody Recognition Site in the Third IgG‐Binding Domain of Protein G

Protein dynamics occurring on a wide range of timescales play a crucial role in governing protein function. Particularly, motions between the globular rotational correlation time ( ) and 40 μs (supra‐ window), strongly influence molecular recognition. This supra‐ window was previously hidden, owing to a lack of experimental methods. Recently, we have developed a high‐power relaxation dispersion (RD) experiment for measuring kinetics as fast as 4 μs. For the first time, this method, performed under super‐cooled conditions, enabled us to detect a global motion in the first β‐turn of the third IgG‐binding domain of protein G (GB3), which was extrapolated to 371±115 ns at 310 K. Furthermore, the same residues show the plasticity in the model‐free residual dipolar coupling (RDC) order parameters and in an ensemble encoding the supra‐ dynamics. This β‐turn is involved in antibody binding, exhibiting the potential link of the observed supra‐ motion with molecular recognition.     

Stabilization of a nonlinear flow-plate interaction via component-wise decomposition

Asymptotic-in-time interior feedback control of a panel interacting with an inviscid, subsonic flow is considered. The classical model [8] is given by a clamped nonlinear plate strongly coupled to a convected wave equation on the half space. In the absence of energy dissipation the plate dynamics converge to a compact and finite dimensional set [6, 7]. With a sufficiently large velocity feedback control on the structure we show that the full flow-plate system exhibits strong convergence to the set of stationary states in the natural energy topology. We show a decomposition of the dynamics into “smooth” component and global-in-timeHadamard continuous component, thus permitting approximation by smooth data. That the flows are subsonic is critical for our approach. Our result implies that flutter (a periodic or chaotic end behavior) is not present in subsonic flows with sufficient viscous damping in the structure.     

Nonpeptidic Selective Inhibitors of the Chymotrypsin‐Like (β5 i) Subunit of the Immunoproteasome

Elevated expression of the immunoproteasome has been associated with autoimmune diseases, inflammatory diseases, and various types of cancer. Selective inhibitors of the immunoproteasome are not only scarce, but also almost entirely restricted to peptide‐based compounds. Herein, we describe nonpeptidic reversible inhibitors that selectively block the chymotrypsin‐like (β5i) subunit of the human immunoproteasome in the low micromolar range. The most potent of the reversibly acting compounds were then converted into covalent, irreversible, nonpeptidic inhibitors that retained selectivity for the β5i subunit. In addition, these inhibitors discriminate between the immunoproteasome and the constitutive proteasome in cell‐based assays. Along with their lack of cytotoxicity, these data point to these nonpeptidic compounds being suitable for further investigation as β5i‐selective probes for possible application in noncancer diseases related to the immunoproteasome.     

Palladium complexes: new candidates for anti-cancer drugs

Platinum complexes which are most studied metal complexes due to their importance as adjuvant therapy of cancers aiming to induce tumor-cell-death. Some of the platinum-based antitumor drugs like cisplatin, carboplatin and oxaliplatin, have several disadvantages including side effects, cisplatin-resistant tumors, limited solubility in aqueous media, and so on. Thus, to achieve lower undesirable toxicity, enhanced solubility, and tumor selectivity, significant amount of work have been devoted to the preparation of modified platinum complexes. One of the ways to design the new anti-tumor agents related to cisplatin is to change the nature of central metal ion. Among the non-platinum metal complexes studied for cancer treatment, palladium(II) derivatives were readily chosen due to their structural analogy with those containing Pt(II) complexes. This review focuses on anti-tumor property of Pd(II) complexes and makes comparisons with similar property of cisplatin. Then, in the review, palladium(II) complexes have been classified according to their leaving ligands into palladium(II) complexes. In the last part, the most important factors affecting on the anti-tumor activity of the Pd(II) complexes were discussed. These factors are encouraging more researches in this field, for future applications.     

Catalytic Conversion of Macroalgae-derived Alginate to Useful Chemicals

Alginate, a main carbohydrate compound of macroalgae, can be hydrothermally converted to valuable organic products, such as furfural and organic acids, over various types of catalysts. In this review, alginate is evaluated as a renewable biomass feedstock for the production of the useful chemicals, based on the structural differences between alginate and conventional lignocellulosic biomass feedstocks. The influence of different catalysts and reaction conditions on the alginate depolymerization and the product distribution is discussed. Finally, future research direction for the catalytic conversion of alginate is suggested.     

15N-NMR Spectra of Azoles with Two Heteroatoms

The ¹⁵N-NMR spectra of azoles, with natural isotope abundance, have been measured under different experimental conditions, and chemical shifts are reported for imidazoles, pyrazoles, oxazoles, isoxazoles, thiazoles, and isothiazoles. General trends of substituent effects in this heterocyclic series are discussed based on the data of 67 substituted azoles, dihydro- and tetrahydroazoles. ¹⁵N, ¹H spin-coupling constants have been determined from spectra obtained by [¹H] → ¹⁵N polarizationtransfer experiments, i.e. an application of INEPT and DEPT pulse sequences. Two-bond and three-bond coupling constants are fully assigned and are discussed in terms of the specific pathways in azoles. The potential of structural applications of the new data is illustrated for isomeric nitro-imidazoles and highly-substituted pyrazoles, and in the case of ring-chain tautomerism of 2-substituted tetrahydrooxazoles.     

Absolute stereochemistry of yohimbine and reserpine

The absolute configurations of yohimbine and reserpine based upon the optical rotation studies, but no chemical proof, have been indicated by formulae I and II respectively. In this paper, the Prelog's asymmetric synthesis is applied with success to yohimbine(I) and methyl reserpate(IV), thereby providing evidence for the correctness of the formulae. Furthermore, yohimbine is directly correlated with dihydrocorynantheane(XVII) of known absolute stereochemistry, conclusively establishing the absolute stereochemistry of a number of yohimbine alkaloids.     

Breakthrough in the direct conversion of methane into c1-oxygenates

The partial oxidation of methane to CH3OH and HCHO (C1-oxygenates) was evaluated over a low surface area V2O5/SiO2 catalyst. The introduction of low amounts of NO (0-2.92% vol) to the reaction feed strongly enhanced both the conversion of methane and selectivity to C1-oxygenates. In the presence of NO, both the reaction temperature and the CH4/O2 ratio affected selectivity to CH3OH and HCHO. Selectivity values of C1-oxygenates as high as 40% at a methane conversion close to 40% were obtained.     

On the Allotropy of Arsenic

The system As? Hg was investigated using low temperature X-ray diffraction (200 and 120 K). The samples ranging in composition from 1 to 60 at.-% Hg were alternatively slowly cooled and /or quenched from 700°C. The first series crystallizes as a solid solution of Hg in rhombohedral α-As. Quenched samples possess orthorhombic structure, identical with the mineral “arsenolamprit” (?-As) and are isomorphous with Bridgmans high pressure or mercury doped black phosphorus. The same form is obtained in the course of the disproportionation reaction 5 As₂O₃ ? As₄ + 3 As₂O₅. The orthorhombic modification absorbs an appreciable amount of helium, but it decreases as the mercury content becomes bigger. It is concluded that besides the formation of the solid solution As? Hg some foreign atoms may fill the voids which are present in ?-As.