Impact of dietary n−3 FA deficiency on rat bone tissue FA composition

The effect of dietary n−3 FA deficiency on bone tissue FA composition was evaluated in growing rats. Two mixtures combining hydrogenated coconut oil with safflower oil served as the n−3-deficient dietary treatments and provided two levels of linoleic acid (LA). The n−3 treatments were formulated with added α-linolenic acid (LNA) from flaxseed oil (diet LNA) or LNA plus DHA, and both were balanced for LA. This study showed that bone is sensitive to changes in dietary n−3 FA and that DHA is more effective than LNA in maintaining DHA levels in these tissues.     

Are chemical alarm cues conserved within salmonid fishes?

A wide diversity of fishes possess chemical alarm signalling systems. However, it is not known whether the specific chemicals that act as alarm signals are conserved within most taxonomic groups. In this study we tested whether cross-species responses to chemical alarm signals occurred within salmonid fishes. In separate laboratory experiments, we exposed brook charr (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Oncorhynchus mykiss) to chemical alarm signals from each of the three salmonid species and from swordtails (Xiphophorus helleri). In each case, the test species responded with appropriate antipredator behavior to all three salmonids alarm cues, but did not react to swordtail cues. These data suggest that chemical alarm cues are partially conserved within the Family Salmonidae. For each species tested, the intensity of the response was stronger to conspecific alarm cues, than to heterospecific alarm cues, indicating that salmonids could distinguish between chemical cues of conspecifics versus heterospecifics. These results suggest that the chemical(s) that act as the alarm cues may be: 1) identical and that there may be other chemical(s) that allow the test fish to distinguish between conspecifics and heterospecifics, or 2) that the cues that act as signals are not identical, but are similar enough to be recognized.     

Functional properties and protein concentrate of Pigeon pea (Cajanus cajan (I.) Millsp) flour

The objective of this investigation was to study the functional properties of Pigeon pea (Cajanus cajan (L.) Millsp) flour and protein concentrate. The solubility of both samples were superior than 70% at pH above 6.7 and below 3.5. The water and oil absorption were 1.2 and 1.07 ml/g of sample and 0.87 and 1.73 ml/g of flour and protein concentrate samples, respectively. The minimum concentration of flour and protein concentrate needed for gelation was 20% and 12%, respectively. The emulsifying capacity of flour and concentrate was 129.35 g and 191.66 g oil/g of protein and the emulsion stability 87.50 and 97.97%, respectively, after 780 minutes. The foam capacity and stability of flour foam were 36.0% and 18.61, while of the concentrate were 44.70% and 78.97% after 90 minutes. These properties indicate that the flour as well as the concentrate could have application in various food systems.     

Women and Smokers Have Elevated Urinary F2-Isoprostane Metabolites: A Novel Extraction and LC–MS Methodology

F(2)-Isoprostanes (F(2)-IsoPs), regio- and stereoisomers of prostaglandin F(2alpha) (PGF(2alpha)), and urinary F(2)-IsoP metabolites including 2,3-dinor-5,6-dihydro-8-iso-PGF(2alpha) [2,3-dinor-8-iso-PGF(1alpha) (2,3-dinor-F1)] and 2,3 dinor-8-iso-PGF(2alpha) (2,3-dinor-F2), have all been used as biomarkers of oxidative stress. A novel method was developed to measure these biomarkers using a single solid phase extraction (SPE) cartridge, separation by HPLC, and detection by negative mode selected reaction monitoring (SRM) mass spectrometry (MS), using authentic standards of PGF(2alpha); 8-iso-PGF(2alpha); 2,3-dinor-F1 and 2,3-dinor-F2 to identify specific chromatographic peaks. The method was validated in a population of healthy, college-aged nonsmokers (n = 6 M/8F) and smokers (n = 6 M/5F). Urinary F(2)-IsoP concentrations were approximately 0.2-1.5 microg/g creatinine, 2,3-dinor-F1 was approximately1-3 microg/g and 2,3-dinor-F2 was approximately 3-5 microg/g. Additional F(2)-IsoPs metabolites were identified using SRM. The sum of all urinary F(2)-IsoP metabolites was 50-100 microg/g creatinine indicating their greater abundance than F(2)-IsoPs. Women had higher F(2)-IsoP metabolite concentrations than did men (MANOVA, main effect P = 0.003); cigarette smokers had higher concentrations than did nonsmokers (main effect P = 0.036). For men or women, respectively, smokers had higher metabolite concentrations than did nonsmokers (P < 0.05). Thus, our method simultaneously allows measurement of urinary F(2)-IsoPs and their metabolites for the determination of oxidative stress.     

Treatment of parking lot stormwater using a StormTreat system

The effectiveness of a StormTreat system in treating stormwater from a commercial parking lot in Connecticut was evaluated. Flow-weighted composite samples were collected from StormTreat inflow and outflow during a 2-yr study. Bypass flow was not monitored. The StormTreat significantly (P < 0.05) reduced total suspended solids, total phosphorus, total Kjeldahl-N, total zinc, total copper, and fecal coliform bacteria on a concentration basis. The StormTreat system retained 49% total suspended solids, 74% total phosphorus, 44% total Kjeldahl-N, 45% total zinc, 29% total copper, 2% total lead on a mass basis, and 99% fecal coliform on a concentration basis. Treatment efficiency was not associated with storm size, chamber stage, discharge rate, or hydraulic retention time (r < 0.355). The system retained ammonia-N more efficiently during the summer than during the winter (P < 0.01) and retained total zinc less efficiently during the summer than during the winter (P < 0.05). Season did not significantly (P > 0.05) affect the treatment of other monitored water quality variables. The StormTreat system reduced the concentrations of stormwater pollutants commonly found in parking lot runoff.     

Optimization of a mist chamber (Cofer scrubber) for sampling water-soluble organics in air

While the atmospheric fate and transport of biogenic and anthropogenic hydrocarbons has been extensively studied, little is known about the behavior of first-, second-, and third generation photo-oxidation products that arise from OH radical oxidation of the parent species. The results of chamber experiments establish that *OH oxidation of biogenic and anthropogenic hydrocarbons yields carbonyls, dicarbonyls, hydroxycarbonyls, and keto-acids. However, little is known about the generation and fate of these products in the ambient atmospheric environment. This is changing because of the advent of methods that rely on 0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) derivatization of carbonyls in concert with gas chromatography/ion trap mass spectrometry. Such methods provide the means to identify and quantify water-soluble organics, which historically have been difficult to measure. A limitation of existing sampling methods, however, is the use of devices that require low flow rates (0.5-1 L min(-1)). Accordingly, long sampling times (3-4 h) are needed to obtain pptv-ppbv detection limits. The mist chamber is an attractive device because of the high flow rates (25-70 L min(-1)) compatible with its use. Herein, we evaluate a mist chamber using a flow rate of 25-30 L min(-1) to provide short (10 min) sampling times and pptv limits of detection. The results establish a relationship between the Henry's law constant (KH) and the collection efficiency and demonstrate the suitability of the method to measure analytes with KH > or = 10(3) M atm(-1). Adjusting the pH, adding quaternary ammonium salts, or decreasing the temperature of the collecting solution in the mist chamber did not significantly affect the collection efficiency. We tested the method by sampling photooxidation products of isoprene (glyoxal, methylglyoxal, hydroxyacetone, and glycolaldehyde) in the Blodgett Forest, CA. This is the first report of a study the employs the mist chamberto sample hydroxycarbonyls. The accuracy and the reproducibility of the method were evaluated by the analysis of duplicate samples and field spikes. The mean recovery of field spikes was > or =80%, and the relative standard deviation was < or =22% between duplicate measurements. The detection limits were 48, 15, 7.7, and 2.7 pptv for glycolaldehyde, hydroxyacetone, methylglyoxal, and glyoxal, respectively. This work demonstrates the power of the mist chamber in concert with PFBHA derivatization and mass spectrometry to measure pptv concentrations of water-soluble organics with a sampling time of 10 min.     

Inhibition of bacterial foodborne pathogens by the lactoperoxidase system in combination with monolaurin

The lactoperoxidase system (LPS) and monolaurin (ML) are potential natural antimicrobial agents for use in foods. The LPS is considered to have greatest activity against Gram-negative bacteria while ML is usually considered to have greatest activity against Gram-positive bacteria. An LPS-ML combination system (utilizing lactoperoxidase (LPX) in the range 5-200 mg kg(-1) and ML in the range 50-1,000 ppm) inhibited growth of Escherichia coli O157:H7 and Staphylococcus aureus. Growth of S. aureus was inhibited more strongly in broth than in milk, in milk than in ground beef A similar pattern was observed for E. coli O157:H7, though enhanced inhibition by LPS-ML systems over that obtained in comparable LPS only systems was not observed in ground beef The inhibitory action of the LPS in combination with other lipids was also examined, with progressively weaker inhibition observed in combinations including palmitoleic acid, monopalmitolein, lauric acid, caprylic acid, and sodium lauryl sulphate.     

Simulation of packed-bed chromatography utilizing high-resolution flow fields: comparison with models

A computer simulation of a section of the interior region of a liquid chromatographic column is performed. The detailed fluid flow profile is provided from a microscopic calculation of low Reynolds number flow through a random packed bed of nonporous spherical particles. The fluid mechanical calculations are performed on a parallel processor computer utilizing the lattice Boltzmann technique. Convection, diffusion, and retention in this flow field are calculated using a stochastic-based algorithm. This computational scheme provides for the ability to reproduce the essential dynamics of the chromatographic process from the fundamental considerations of particle geometry, particle size, flow velocity, solute diffusion coefficient, and solute retention parameters when retention is utilized. The simulation data are fit to semiempirical models. The best agreement is found for the "coupling" model of Giddings and the four-parameter Knox model. These models are verified over a wide range of particle sizes and flow velocities at both low and high velocity. The simulations appear to capture the essential dynamics of the chromatographic flow process for non-dimensional flow velocities (Péclet number) less than 500. Since the same packing geometry is utilized for different particle size studies, the interpretation of the parameter estimates from these models can be extended to the physical column model. The simulations reported here agree very well with a number of experiments reported previously.     

Analysis of Seidel aberration by use of the discrete wavelet transform

Seidel aberration coefficients can be expressed by Zernike coefficients. The least-squares matrix-inversion method of determining Zernike coefficients from a sampled wave front with measurement noise has been found to be numerically unstable. We present a method of estimating the Seidel aberration coefficients by using a two-dimensional discrete wavelet transform. This method is applied to analyze the wave front of an optical system, and we obtain not only more-accurate Seidel aberration coefficients, but we also speed the computation. Three simulated wave fronts are fitted, and simulation results are shown for spherical aberration, coma, astigmatism, and defocus.