Kinetics of the gas‐phase reaction of n‐C6–C10 aldehydes with the nitrate radical

Rate coefficients for gas‐phase reaction between nitrate radicals and the n‐C₆–C₁₀ aldehydes have been determined by a relative rate technique. All experiments were carried out at 297 ± 2 K, 1020 ± 10 mbar and using synthetic air or nitrogen as the bath gas. The experiments were made with a collapsible sampling bag as reaction chamber, employing solid‐phase micro extraction for sampling and gas chromatography/flame ionization detection for analysis of the reaction mixtures. One limited set of experiments was carried out using a glass reactor and long‐path FTIR spectroscopy. The results show good agreement between the different techniques and conditions employed as well as with previous studies (where available). With butanal as reference compound, the determined values (in units of 10^?14 cm³ molecule^?1 s^?1) for each of the aldehydes were as follows: hexanal, 1.7 ± 0.1; heptanal, 2.1 ± 0.3; octanal, 1.5 ± 0.2; nonanal, 1.8 ± 0.2; and decanal, 2.2 ± 0.4. With propene as reference compound, the determined rate coefficients were as follows: heptanal, 1.9 ± 0.2; octanal, 2.0 ± 0.3; and nonanal, 2.2 ± 0.3. With 1‐butene as reference compound, the rate coefficients for hexanal and heptanal were 1.6 ± 0.2 and 1.8 ± 0.1, respectively. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 120–129, 2003     

Determination of A0 for the symmetric top molecules

A new method for the determination of the constant A₀ in symmetric top molecules is proposed. This method utilizes the data for the overtone bands of a doubly degenerate vibration of symmetry species E_1u. Transitions necessary for the determination of A₀ have been indicated for all symmetric top symmetry groups. The precision of A₀ values determined according to the method suggested is also discussed.     

On the Power Function of the Likelihood Ratio Test for MANOVA

We prove that the power function of the likelihood ratio test for MANOVA attains its minimum when the rank of the location parameter matrix Θ decreases from s to 1. This provides a theoretical justification of a result that is known in the literature based only on numerical studies.     

Toward a global characterization of the phosphoproteome in prostate cancer cells: identification of phosphoproteins in the LNCaP cell line

Protein phosphorylation plays a major role in most cell-signaling pathways in all eukaryotic cells. Disruptions in phosphorylation-mediated cell-signaling events are associated with various diseases, including cancer. Here, we applied a fully non-gel-based methodology to obtain an initial panel of phosphoproteins from the LNCaP human prostate cancer cell line. The analytical strategy involved enrichment of phosphopeptides by immobilized metal ion affinity chromatography, the use of POROS Oligo R3 to capture phosphopeptides that were not retained with a C18 packing, and gas-phase fractionation in the m/z dimension to extend the dynamic range of the LC-MS/MS analysis. In this pilot investigation, 137 phosphorylation sites in 81 phosphoproteins were identified. The characterized phosphoproteins include kinases, co-regulators of steroid receptors, and a number of cancer-related proteins.     

Ion association and hydration in aqueous solutions of LiCl and Li2SO4 by dielectric spectroscopy

A systematic study of the dielectric relaxation spectra of aqueous solutions of LiCl and Li2SO4 has been made at solute concentrations of 0.05 < or = c/M < or = 1.0 and 2.0, respectively, and over a wide range of frequencies (0.2 < or = nu/GHz < or = 89) at 25 degrees C. The spectra were best described by a superposition of four Debye processes, consisting of the two well-known water relaxations at ca. 8 and 0.5 ps and two ion-pair contributions at ca. 200 and 20 ps, corresponding to the presence of double-solvent-separated (2SIP) and solvent-shared (SIP) ion pairs, respectively. Consistent with spectroscopic studies, no contact ion pairs were detected over the studied concentration range. The overall ion association constants K(o)(A) obtained were in good agreement with literature data for both salts. Detailed analysis of the solvent relaxations indicated that Li+ has a significant second solvation sheath although there were differences between the effective hydration numbers obtained from LiCl and Li2SO4, which might arise from competition for the solvent from the anions.     

Investigation of phosphoprotein signatures of archived prostate cancer tissue specimens via proteomic analysis

Early detection of prostate cancer and determination of its aggressiveness are critical factors that influence treatment outcomes. To aid in the clinical decision making, novel biomarkers are being sought. Direct, global-scale examination of primary human specimens provides the most relevant picture of the tumor machinery and its perturbations, and this information is highly significant in the context of biomarker discovery. In the pilot study reported here, we focused on mapping of the phosphoproteome in human prostate cancer specimens obtained from a tissue repository. A gel-free proteomic strategy included whole proteome digestion, phosphopeptide enrichment with immobilized metal ion affinity chromatography (IMAC), and phosphoprotein identification via LC-MS/MS and database searches. We applied this strategy to obtain phosphoprotein signatures from a set of five specimens. Phosphoproteins were characterized from each specimen. The phosphoprotein panels included 16-23 phosphoproteins that encompassed 18-30 phosphorylation sites. Some of proteins/sites were characterized in multiple specimens, whereas the majority of sites were found in single specimens. The characterized panels include caldesmone, desmin, HSP β-1, synaptopodin-2, filamin-C, tensin-1, and others. In summary, the study showed that cancer-relevant phosphoproteins can be characterized directly from archived prostate tumor specimens, establishing the groundwork for further biomarker discovery.     

Effective correlation-free reduced Hamiltonian for the νt(E), νn(A1) Coriolis-interacting states of C3v symmetric-top molecules

The effective correlation-free vibrational-rotational Hamiltonian for the Coriolis-interacting ν_t(E) and ν_n(A₁) states in C_3v molecules has been derived. The Hamiltonian includes the terms describing the x-y Coriolis interaction up to the fourth-order, and several useful reduction schemes for the Hamiltonian are suggested.     

Epitope mapping of allergen ovalbumin using biofunctionalized magnetic beads packed in microfluidic channels The first step towards epitope-based vaccines

Specific allergen immunotherapy is frequently associated with adverse reactions. Several strategies are being developed to reduce the allergenicity while maintaining the therapeutic benefits. Peptide immunotherapy is one such approach. Methods for the simple and rapid identification of immunogenic epitopes of allergens (i.e. allergenic epitopes) are ongoing and could potentially lead to peptide-based vaccines. An epitope extraction technique, based on biofunctionalized magnetic microspheres self-organized under a magnetic field in a channel of a simple microfluidic device fabricated from polydimethylsiloxane, was applied in the isolation and identification of prospective allergenic epitopes. Similarly to chromatographic column separations, the easily replaceable plug of self-organized beads in the channel benefits especially from an even larger surface-to-volume ratio and an enhanced interaction of the surfaces with passing samples. Ovalbumin, the major protein of egg white and a typical representative of food allergens, was selected as the model molecule. Highly resistant ovalbumin was at first efficiently digested by a magnetic proteolytic reactor with trypsin treated with l-1-tosylamido-2-phenylethyl chloromethyl ketone and the second step, i.e. capture of allergenic epitopes from the mixture of peptides, was performed by a magnetic immunoaffinity carrier with orientedly immobilized rabbit anti-ovalbumin IgG molecules. Captured peptides were released with 0.05% trifluoroacetic acid. The elution fractions were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The peptide fragment of ovalbumin HIATNAVLFFGR (m/z: 1345.75, position: 371-382) was identified as a relevant allergenic epitope in this way. Such a microfluidic magnetic force-based epitope extraction technique applied in the epitope mapping of ovalbumin has the potential to be a significant step towards developing safe and cost-effective epitope-based vaccines.     

Analysis of Coriolis perturbations in the high-resolution infrared spectra of arsine (AsH3)

Numerical methods for the analysis of high-resolution infrared spectra of symmetric top molecules perturbed by Coriolis interactions between degenerate and nondegenerate vibrational levels are discussed in the second order of approximation. Application to the high-resolution infrared spectra of the AsH₃ molecule in the region of the fundamentals ν₁, ν₃ and ν₂, ν₄ yields considerably improved values of the molecular constants of AsH₃, including the band origins rotational constants, Coriolis coupling constants, centrifugal distortion constants, and the parameter of the K-type doubling effect.     

Acetylcholinesterase-Inhibiting Activity of Salicylanilide <em>N</em>-Alkylcarbamates and Their Molecular Docking

A series of twenty-five novel salicylanilide N-alkylcarbamates were investigated as potential acetylcholinesterase inhibitors. The compounds were tested for their ability to inhibit acetylcholinesterase (AChE) from electric eel (Electrophorus electricus L.). Experimental lipophilicity was determined, and the structure-activity relationships are discussed. The mode of binding in the active site of AChE was investigated by molecular docking. All the discussed compounds expressed significantly higher AChE inhibitory activity than rivastigmine and slightly lower than galanthamine. Disubstitution by chlorine in C'_(3,4) of the aniline ring and the optimal length of hexyl-undecyl alkyl chains in the carbamate moiety provided the most active AChE inhibitors. Monochlorination in C'₍₄₎ exhibited slightly more effective AChE inhibitors than in C'₍₃₎. Generally it can be stated that compounds with higher lipophilicity showed higher inhibition, and the activity of the compounds is strongly dependent on the length of the N-alkyl chain.