Theoretical Design of a New Allosteric Switch and Fluorescence Chemosensor Double Functional Devices of Aza-Crown Ether

A novel molecular device (<i>trans</i>-azobenzene embedded <i>N</i>-(11-pyrenyl methyl)­aza-21-<i>crown</i>-7) with double functional devices was designed on the basis of theoretical calculations. Pyrenyl methyl covalently bonded to aza-21-<i>crown</i>-7 at the nitrogen position interacting with a series of alkaline-earth metal cations (Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺) was investigated. The fully optimized geometries and real frequency calculations were investigated using a computational strategy based on density functional theory at B3LYP/6-31G­(d) level. Free ligand (<b>L</b>) and their metal cation complexes (<b>L</b>/M²⁺) were studied using mixed basis set (6-31G­(d) for the atoms C, H, O, and N and LANL2DZ for alkaline-earth metal cations Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺. The natural bond orbital analysis that is based on optimized geometric structures was used to explore the interaction of <b>L</b>/M²⁺ molecules. The absorption spectra of <b>L</b> and <b>L</b>/M²⁺, excitation energies, and absorption wavelength for their excited states were studied by time-dependent density functional theory with 6-31G­(d) and LANL2DZ. A new type of molecular device is found, which has the selectivity to Ca²⁺ and the emission fluorescence of <b>L</b>/Ca²⁺ under the condition of illumination. This molecular device would serve as an allosteric switch and a fluorescence chemosensor

Uptake and Accumulation of Nephrotoxic and Carcinogenic Aristolochic Acids in Food Crops Grown in Aristolochia clematitis-Contaminated Soil and Water

Emerging evidence has suggested aristolochic acids (AAs) are linked to the development of Balkan endemic nephropathy (BEN), a chronic renal disease affecting numerous farmers living in the Balkan peninsula. However, the pathway by which AAs enter the human food chain and cause kidney disease remains poorly understood. Using our previously developed analytical method with high sensitivity and selectivity (Chan, W.; Lee, K. C.; Liu, N.; Cai, Z. <i>J. Chromatogr. A</i> <b>2007</b>, <i>1164</i>, 113–119), we quantified AAs in lettuce, tomato, and spring onion grown in AA-contaminated soil and culture medium. Our study revealed that AAs were being taken up from the soil and bioaccumulated in food crops in a time- and dose-dependent manner. To the best of our knowledge, this study is the first to identify one of the possible pathways by which AAs enter our food chain to cause chronic food poisoning. Results also demonstrated that AAs were resistant to the microbial activity of the soil/water

Rate-Limiting Nutrient Delivery System for Microbial Enhanced Oil Recovery

A limitation of biostimulation for microbial enhanced oil recovery and in situ bioremediation is loss of injectivity that can be encountered when microorganisms grow in the high nutrient concentrations found near the injection well. By encapsulating rate-limiting nutrients, it is hoped that they can be delivered to the target zone without causing near-wellbore biofouling.<br><br>Poster presented at  6^th Annual Graduate Research Poster Competition, University of Kansas School of Engineering, Lawrence, KS. 11 April 2013.<b><br><br></b><br><br><br><br

Quantification of DNA and Protein Adducts of 1‑Nitropyrene: Significantly Higher Levels of Protein than DNA Adducts in the Internal Organs of 1‑Nitropyrene Exposed Rats

1-Nitropyrene (1NP) level is closely associated with the mutagenicity of diesel exhaust and is being used as the marker molecule for diesel exhaust. Thus, quantitation of the exposure to 1NP may provide an efficient method for biomonitoring human exposure to diesel exhaust and risk assessment. Using ultra-performance liquid chromatography coupled with fluorescence or tandem mass spectrometric detection methods, we quantitated and compared in this study the DNA and protein adducts of 1NP in internal organs of 1NP-exposed rats. While previous studies using radioactivity-based detection methods were descriptive in nature and focused on the mutation-associated genetic materials, the results of our quantitative analysis showed, for the first time, a significantly higher concentration of the protein adduct than the DNA adduct in the tissue samples. The data also revealed higher in vivo stability of the protein adduct than that of the DNA adduct. Our results provide solid evidence that demonstrates that the protein adduct might be a more-sensitive dosimeter for 1-NP and, thus, diesel-exhaust exposure

The Epidemiology of Critique

<p>Measurement results of the straight-line distance at the X-axis (unit: mm).</p

Determination of fitting method center points.

<p>Determination of fitting method center points.</p

Measurement results of the straight-line distance at the Z-axis (unit: mm).

<p>Measurement results of the straight-line distance at the Z-axis (unit: mm).</p

Determination of contact method center points.

<p>Determination of contact method center points.</p

Registration of mark points for upper and lower edentulous jaw models and dentures using the RPS registration command.

<p>Registration of mark points for upper and lower edentulous jaw models and dentures using the RPS registration command.</p

Lysine Adduction by Reactive Metabolite(s) of Monocrotaline

Pyrrolizidine alkaloids (PAs) are known hepatotoxins. The execution of the toxicities of the alkaloids requires metabolic activation. Protein modification by reactive metabolites of PAs has been suggested to be an important mechanism of the toxic actions of PAs. The objectives of the present study were to define the interactions of dehydromonocrotaline (DHM) with lysine, lysine derivatives, a model peptide, and bovine serum albumin and to explore the lysine modification of hepatic proteins of animals given monocrotaline. DHM was found to react with the ε-amino group of all model compounds tested after incubation with DHM, and the modification reaction preferentially occurred at C₇ of the necine base. The lysine residue modification with the same regioselectivity was also observed in hepatic proteins of mice treated with monocrotaline. The observed modification increased with the increase in doses administered to the animals. This work allowed us to better understand the mechanisms of the hepatotoxicity of monocrotaline