Full-scale anaerobic bioremediation of trinitrotoluene (TNT) contaminated soil

Applied Biochemistry and Biotechnology - An anaerobic bioremediation process for the degradation of nitroaromatic compounds in soil was demonstrated. Thisex situ process was demonstrated full-scale...     

Separation of herbicides by high-performance liquid chromatography. Influence of water (author's transl)]

The influence of the amount of water dissolved in dichloromethane on the chromatographic separation of herbicides was studied. The selectivity of the mobile phase was demonstrated and compared to another system, dichloromethane modified with 2-propanol. The high efficiency of microporous packing was also demonstrated.     

Efficient synthesis of 19-31 membered macrocyclic tetralactones via ring closing metathesis in ionic liquids

The ring closing metathesis reaction in the presence of Grubbs catalyst was demonstrated using several ionic liquids to synthesize a range of macrocyclic tetralactones having ring size of 19 to 31 membered with different spacers. The ionic liquid [mmim][PF₆] was found to be an excellent solvent and the recovery of the catalyst was demonstrated. X-ray analysis of a representative macrocyclic tetralactone was also reported.     

MgBr2·OEt2 mediated protection of alcohols with hexamethyldisilazane: An efficient catalytic route for the preparation of silyl ethers under solvent-free conditions

Various types of alcohols and phenols were rapidly protected by hexamethyldisilazane in good to excellent yields at room temperature in the presence of catalytic amount of magnesium bromide ethyl etherate under solvent-free conditions. Good to excellent chemoselectivity was demonstrated for competitive protection of primary hydroxyls in the presence of secondary and tertiary alcohols. Highly selective protection of phenols in the presence of aromatic amines was also demonstrated successfully.     

Three-dimensional chiral imaging by sum-frequency generation

A sum-frequency generation (SFG) microscope that is sensitive toward molecular chirality was demonstrated for the first time. Optically active images of chiral 1,1'-bi-2-naphthol solutions were obtained with submicron spatial resolution. Three-dimensional sectioning capability of our microscope was also demonstrated. This optically active SFG microscopy can potentially become a powerful imaging technique for biological samples.     

The [1,5]-Brook rearrangement: an initial application in anion relay chemistry

The [1,5]-Brook rearrangement proceeds efficiently in a series of hydroxyl dithiane substrates with sodium and potassium bases; less effective are lithium bases. That the mode of silyl migration is intramolecular was demonstrated by a crossover experiment. Finally, the tricomponent anion relay chemistry (ARC) coupling tactic was demonstrated employing the [1,5]-Brook rearrangement.     

Water vapor as a carrier gas in capillary gas chromatography

The use of water vapor as carrier gas in capillary chromatography is analyzed. Under equivalent conditions, a comparison of water vapor and helium as a mobile phase was performed during the separation of diesel fuel components. The advantage of water vapor was demonstrated. The resolutions of peaks were calculated for a pair of substances, C₁₈-iso and C₂₀ (4.4 for water vapor and 3.9 for helium). The Van Deemter dependences were measured, and it was demonstrated that the substantially lower viscosity of the water vapor compared to helium makes it possible to perform the separation of substances in a broader range of linear velocities, comparable to hydrogen used as mobile phase. The prospects for using water vapor was demonstrated in chromatographic analysis of hydrocarbons.     

Attempts to assemble a universal NMR database without synthesis of NMR database compounds

[structure: see text] The feasibility of assembling 3JH,H profiles from NMR data collected on relevant, but not necessarily specific, NMR database compounds representing a given stereocluster was demonstrated. By this approach, the 3JH,H profile was created for the contiguous tetraol peracetate stereocluster. The reliability and applicability of the database thus assembled were demonstrated for known peracetates derived from two heptoses.     

The microrheology of polystyrene sulfonate combs in aqueous solution

Video particle tracking (VPT) and diffusing wave spectroscopy were used to characterize the microrheology of polystyrene sulfonate combs in aqueous solutions. At low frequencies VPT demonstrated predominantly viscous behavior. The manner in which the viscosity scaled as a function of monomer concentration was a sensitive function of the comb architecture. Densely branched combs or combs with long side chains demonstrated entangled polyelectrolyte scaling above the overlap concentration, whereas sparsely branched combs had unentangled polyelectrolyte scaling. A dynamic scaling model was developed for the viscosity of unentangled semidilute solutions of comb polyelectrolytes. Diffusing wave spectroscopy demonstrated Rouse modes (G' approximately G" approximately omega12) for the high-frequency dynamics of the semidilute comb solutions. The form of the high-frequency viscoelasticity was independent of the chain architecture and the modulus scaled as expected for linear flexible polyelectrolytes.     

A new trick (hydroxyl radical generation) for an old vitamin (B12)

Photolysis of hydroxocobalamin in the presence of plasmid DNA (pBR322) results in DNA cleavage. Temporal control of hydroxyl radical production and DNA strand scission by hydroxocobalamin was demonstrated using a 2-deoxyribose assay and a plasmid relaxation assay, respectively. The light-driven hydroxocobalamin-mediated catalytic formation of hydroxyl radicals was demonstrated using radical scavenging studies of DNA cleavage and via recycling of a hydroxocobalamin-resin conjugate several times without loss of efficacy.     

Preliminary assessment of the modification of polystyrene‐divinylbenzene resin with lipid‐tethered ligands for selective separations

Functionalized lipid tethered ligands use physical adsorption to anchor reactive head groups to hydrophobic supports. We previously demonstrated the use of these species adsorbed onto polypropylene capillary‐channeled polymer fibers. The general use of lipid tethered ligands on other hydrophobic chromatographic supports is demonstrated here for polystyrene‐divinylbenzene. Evaluation of ligand adsorption conditions was performed using a fluorescein isocyanate head group to quantify the extent of loading by UV‐Vis absorbance and by fluorescence microscopy. Selective protein capture was demonstrated by the detection of Texas Red labeled streptavidin (using fluorescence microscopy imaging, with quantification assessed through the depletion of solution‐phase protein using UV‐Vis absorbance. A second demonstration of the coupling involved an iminodiacetic acid head group lipid tethered ligand to capture the cationic dye, methylene blue. Two common means of alleviating nonspecific binding, adsorption in detergent media and use of a bovine serum albumin block, were evaluated. The first was found to cause release of the ligands, while the second was nominally effective. Indeed, the lipid tethered ligands itself may be most effective at impeding nonspecific binding. While further optimization and chromatographic evaluation is required, the general viability of this ligand immobilization method onto this common polymer support is demonstrated.     

High-performance liquid chromatographic determination of Tornalate in solution dosage forms; a specificity study

A reversed-phase high-performance liquid chromatographic method has been applied utilizing ion-pairing to measure Tornalate in solution dosage forms. Specificity of the method was demonstrated by selectivity for Tornalate analysis, analysis of stressed samples and by peak homogeneity tests. These included the diode-array derived spectral overlay test and fraction collection with rechromatography in an alternate normal phase system. Linearity was also demonstrated in terms of recovery from synthetic samples and detector response.     

Self-aspirating atmospheric pressure chemical ionization source for direct sampling of analytes on surfaces and in liquid solutions

A self-aspirating heated nebulizer probe is described and demonstrated for use in the direct analysis of analytes on surfaces and in liquid samples by atmospheric pressure chemical ionization (APCI) mass spectrometry. Functionality and performance of the probe as a self-aspirating APCI source is demonstrated using reserpine and progesterone as test compounds. The utility of the probe to sample analytes directly from surfaces was demonstrated first by scanning development lanes of a reversed-phase thin-layer chromatography plate in which a three-component dye mixture, viz., Fat Red 7B, Solvent Green 3, and Solvent Blue 35, was spotted and the components were separated. Development lanes were scanned by the sampling probe operated under computer control (x, y plane) while full-scan mass spectra were recorded using a quadrupole ion trap mass spectrometer. In addition, the ability to sample the surface of pharmaceutical tablets (viz., Extra Strength Tylenol and Evista tablets) and to detect the active ingredients (acetaminophen and raloxifene, respectively) selectively was demonstrated using tandem mass spectrometry (MS/MS). Finally, the capability to sample analyte solutions from the wells of a 384-well microtiter plate and to perform quantitative analyses using MS/MS detection was illustrated with cotinine standards spiked with cotinine-d3 as an internal standard.     

Determination of mercury in natural samples at the sub-nanogram level using inductively coupled plasma/mass spectrometry after reduction to elemental mercury

Inductively coupled plasma/mass spectrometry was used to determine mercury. Sodium borohydride was used to reduce the mercury to its elemental form, which was purged directly to the plasma using the nebulizer gas. Applications to natural waters and reference sediment are demonstrated. The detection limit, defined as three times the standard deviation of the blank, is 8 pg. The precision at the 100-pg level is 3%. The ability to make isotope dilution measurements is demonstrated.     

Chemoenzymatic synthesis of glutamic acid analogues: substrate specificity and synthetic applications of branched chain aminotransferase from Escherichia coli

A new route to alpha-keto acids is described, based on the ozonolysis of enol acetates obtained from alpha-substituted beta-keto esters. Escherichia coli branched chain aminotransferase (BCAT) activity toward a variety of substituted 2-oxoglutaric acids was demonstrated analytically. BCAT was shown to have a broad substrate spectrum, complementary to that of aspartate aminotransferase, and to offer access to a variety of glutamic acid analogues. The usefulness of BCAT was demonstrated through the synthesis of several 3- and 4-substituted derivatives.     

ULTRAMINE: a high-capacity polyethylene-imine-based polymer and its application as a scavenger resin

The synthesis of a novel high-loading polyethylene-imine resin (ULTRAMINE) is described, and its application as a scavenger resin in various acylation reactions is demonstrated. The inverse suspension polymerization technique was used for the synthesis of well-defined spherical polymer beads. Polymer beads with different cross-linking densities were synthesized according to the degree of acryloylation of the polyethylene-imine polymer. The resin was characterized by various spectroscopic techniques. The size, shape, and morphological features of the resin were demonstrated by microscopy. The resin showed excellent swelling properties in both polar and nonpolar solvents. The chemical stability of the resin in various reagents and solvents was investigated and monitored by IR spectroscopy. The mechanical stability of the beads was determined by a single-bead compressive experiment. The ULTRAMINE beads can be used as an excellent scavenger for excess acylating reagent, as demonstrated for a variety of reactions. ULTRAMINE-red resin was derived from ULTRAMINE through exhaustive reduction of the amide carbonyl groups to yield an all-amine resin.     

Lectin fromDatura innoxia seeds: Isolation and activity in tissue culture

Lectin was isolated from seeds of IndianDatura innoxia. Certain of its physicochemical properties were determined. Its hemaglutinizing activity was demonstrated. The effect of the obtained protein on proliferation of the hybrid KML cell line from murine B-16 melanoma was studied. Its mitogenic properties were demonstrated.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 257–258, May–June, 2000.     

Electrospray Post-Ionization Mass Spectrometry of Electrosurgical Aerosols

The feasibility of electrospray (ES) ionization of aerosols generated by electrosurgical disintegration methods was investigated. Although electrosurgery itself was demonstrated to produce gaseous ions, post-ionization methods were implemented to enhance the ion yield, especially in those cases when the ion current produced by the applied electrosurgical method is not sufficient for MS analysis. Post-ionization was implemented by mounting an ES emitter onto a Venturi pump, which is used for ion transfer. The effect of various parameters including geometry, high voltage setting, flow parameters, and solvent composition was investigated in detail. Experimental setups were optimized accordingly. ES post-ionization was found to yield spectra similar to those obtained by the REIMS technique, featuring predominantly lipid-type species. Signal enhancement was 20- to 50-fold compared with electrosurgical disintegration in positive mode, while no improvement was observed in negative mode. ES post-ionization was also demonstrated to allow the detection of non-lipid type species in the electrosurgical aerosol, including drug molecules. Since the tissue specificity of the MS data was preserved in the ES post-ionization setup, feasibility of tissue identification was demonstrated using different electrosurgical methods.     

Towards Platinum(II) Complexes for in cellulo Applications: Synthesis,Characterization, Biological and Catalytic Evaluation

With the aim of achieving bioorthogonal intracellular catalysis, a library of platinum(II) complexes was synthesized. Their non-toxicity to living cells was demonstrated and their catalytic activity was evaluated on a cyclization reaction leading to a highly fluorescent coumarin. None of the platinum complexes showed any catalytic activity for coumarin synthesis. Still, we demonstrated that the silver salt AgSbF₆ commonly used to ‘activate’ metal catalysts by removing a chloride is a very efficient catalyst for the studied intramolecular cyclization reaction.