Aberrant proteins in the saliva of patients with oral squamous cell carcinoma

Confirmation of oral squamous cell cancer (OSCC) currently relies on histological analysis, which does not provide clear indication of cancer development from precancerous lesions. In the present study, whole saliva proteins of patients with OSCC (n = 12) and healthy subjects (n = 12) were separated by 2DE to identify potential candidate biomarkers that are much needed to improve detection of the cancer. The OSCC patients’ 2DE saliva protein profiles appeared unique and different from those obtained from the healthy subjects. The patients’ saliva α1‐antitrypsin (AAT) and haptoglobin (HAP) β chains were resolved into polypeptide spots with increased microheterogeneity, although these were not apparent in their sera. Their 2DE protein profiles also showed presence of hemopexin and α‐1B glycoprotein, which were not detected in the profiles of the control saliva. When subjected to densitometry analysis, significant altered levels of AAT, complement C3, transferrin, transthyretin, and β chains of fibrinogen and HAP were detected. The increased levels of saliva AAT, HAP, complement C3, hemopexin, and transthyretin in the OSCC patients were validated by ELISA. The strong association of AAT and HAP with OSCC was further supported by immunohistochemical staining of cancer tissues. The differently expressed saliva proteins may be useful complementary biomarkers for the early detection and/or monitoring of OSCC, although this requires validation in clinically representative populations.     

Synthesis of Benzoxazoles Catalyzed by MCM-41, a Green and Reusable Catalyst

Benzoxazoles can be rapidly and efficiently synthesized from acyl chloride with 2-aminophenols in one simple step, which provided a practical and efficient method for high-throughput synthesis of this important class of heterocyclic compounds.     

Solid State Deoximation with Clay SupportedAmmonium Chlorochromate: Regenerationof Carbonyl Compounds Using Microwavesin a Solventless System

Summary.  Ammonium chlorochromate adsorbed on montmorillonite K-10 rapidly regenerates carbonyl compounds from their corresponding oximes under microwave irradiation and solvent-free conditions. Received October 11, 1999. Accepted (revised) November 15, 1999     

Carboxylations of alkali metal phenoxides with carbon dioxide

The reaction mechanism of the Kolbe-Schmitt reaction of phenol and 2-naphthol has been investigated. An alkali metal phenoxide-CO2 complex is not an intermediate that can be easily transformed into a carboxylic acid, such as salicylic acid (SA) and p-hydroxybenzoic acid (pHBA). A direct carboxylation of phenoxide with CO2 takes place even at room temperature, and is competitive with the formation of the CO2 complex. The resulting complex decomposes thermally (above ca. 100 degrees C) to phenoxide, which then undergoes further competitive reactions. Experiments using a carbon-13 labeled complex support a mechanism of direct carboxylation, and not the mechanism via a CO2 complex. The reactivity, C-13 NMR and MOPAC/PM3 calculations suggest a new carbonate-like structure for the CO2 complex.     

Titrimetric determination of microgram amounts of thallium(I) by thiocyanate amplification after precipitation as thallium hexathiocyanatochromate(III)

Summary Thallium (5–200g) is precipitated as Tl₃Cr(SCN)₆. The precipitate is collected, then treated with 10% sodium carbonate solution, and the thiocyanate dissolved is oxidized to sulphate by iodine at pH 8.2. After acidification, the excess of iodine is extracted into chloroform, and the iodide in the aqueous solution is determined by the Leipert amplification procedure. The method provides 76 iodine atoms for each original thallium(I) ion. Copper(II), mercury(II), bismuth, lead and silver interfere seriously, the first three causing negative errors and the other two positive errors.

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Maanalytische Bestimmung von Mikrogrammengen Thallium(I) durch Vervielfachung mit Thiocyanat nach Fällung als Thalliumhexathiocyanatochromat(III)

Zusammenfassung Thallium (5–200g) wird als Tl₃Cr(SCN)₆ gefällt. Der gesammelte Niederschlag wird mit 10% iger Sodalösung behandelt und das gelöste Thiocyanat mit Jod bei pH 8,2 zu Sulfat oxydiert. Nach Ansäuern wird der Jodüberschuß mit Chloroform extrahiert und das Jodid in der wäßrigen Lösung nach Leipert titriert. Dabei entsprechen 76 Jodatome einem ursprünglichen Thallium(I)ion. Cu(II), Hg(II), Bi, Pb und Ag stören stark und verursachen negative bzw. im Falle Pb und Ag positive Fehler.

     

Polymorph exploration of bismuth stannate using first-principles phonon mode mapping

Accurately modelling polymorphism in crystalline solids remains a key challenge in computational chemistry. In this work, we apply a theoretically-rigorous phonon mode-mapping approach to understand the polymorphism in the ternary metal oxide Bi₂Sn₂O₇. Starting from the high-temperature cubic pyrochlore aristotype, we systematically explore the structural potential-energy surface and recover the two known low-temperature phases alongside three new metastable phases, together with the transition pathways connecting them. This first-principles lattice-dynamics method is completely general and provides a practical means to identify and characterise the stable polymorphs and phase transitions in materials with complex crystal structures.

Using a phonon mode-mapping approach, we recover the known experimental phases of the ternary oxide Bi₂Sn₂O₇ and identify three new metastable phases, highlighting the utility of the method for polymorph prediction on many other complex materials.     

Experimental Investigation on Thermophysical Properties of Ammonium-Based Protic Ionic Liquids and Their Potential Ability towards CO2 Capture

Ionic liquids, which are extensively known as low-melting-point salts, have received significant attention as the promising solvent for CO₂ capture. This work presents the synthesis, thermophysical properties and the CO₂ absorption of a series of ammonium cations coupled with carboxylate anions producing ammonium-based protic ionic liquids (PILs), namely 2-ethylhexylammonium pentanoate ([EHA][C5]), 2-ethylhexylammonium hexanoate ([EHA][C6]), 2-ethylhexylammonium heptanoate ([EHA][C7]), bis-(2-ethylhexyl)ammonium pentanoate ([BEHA][C5]), bis-(2-ethylhexyl)ammonium hexanoate ([BEHA][C6]) and bis-(2-ethylhexyl)ammonium heptanoate ([BEHA][C7]). The chemical structures of the PILs were confirmed by using Nuclear Magnetic Resonance (NMR) spectroscopy while the density (ρ) and the dynamic viscosity (η) of the PILs were determined and analyzed in a range from 293.15K up to 363.15K. The refractive index (n_D) was also measured at T = (293.15 to 333.15) K. Thermal analyses conducted via a thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC) indicated that all PILs have the thermal decomposition temperature, T_d of greater than 416K and the presence of glass transition, T_g was detected in each PIL. The CO₂ absorption of the PILs was studied up to 29 bar at 298.15 K and the experimental results showed that [BEHA][C7] had the highest CO₂ absorption with 0.78 mol at 29 bar. The CO₂ absorption values increase in the order of [C5] < [C6] < [C7] anion regardless of the nature of the cation.     

Coupled pore network model for the cathode gas diffusion layer in PEM fuel cells

Acta Mechanica Sinica - A pore network model (PNM) is developed for gas diffusion layer (GDL) in the cathode side of polymer electrolyte membrane fuel cells (PEMFCs). The model is coupled to...     

A symmetry based investigation of the band gap of SWCNTs

In this paper we use symmetry of Single Walled Carbon Nanotubes (SWCNTs) to generate some types of virtual sub-bands that are lower in number than the real sub-bands obtained through conventional-TB. It is shown that the virtual sub-bands maintain the value of band gap. In obtaining the sub bands, the interactions of the nearest and the second and third-nearest neighbors are taken into account. As the consequence of lower number of sub-bands, a significant reduction in computational effort has occurred and made the approach useful.