Global tropospheric and total ozone monitoring with a double-etalon fabry-perot interferometer. I. Instrument concept

The global distribution of tropospheric ozone (O(3)) can be observed from a satellite-based instrument by spectrally isolating the pressure-broadened wings of strong O(3) lines. The Fabry-Perot interferometer (FPI) provides high spectral resolution and high-throughput capabilities that are essential for performing such a measurement. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O(3) measurements can simultaneously observe a stratospheric component and thus the total O(3) column abundance. We present a conceptual instrument design that involves a double-etalon fixed-gap series configuration FPI along with an ultranarrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately 0.068 cm(-1), sampling the narrow 1054.2-1055.2 cm(-1) spectral region within the strong 9.6-mum ozone infrared band from a nadir-viewing satellite configuration.     

Comparison of two- and three-dimensional reconstruction methods in optical tomography

We present a three-dimensional (3D) image reconstruction scheme for optical near-infrared imaging of highly scattering material. The algorithm reconstructs the spatial distribution of the optical parameters of a volume Omega from transillumination measurements on the boundary of Omega. We test the performance of the method for a cylindrical object with embedded absorbing perturbation for a number of different source and detector arrangements. Furthermore, we investigate the effect of a mismatched reconstruction, using a two-dimensional (2D) reconstruction model to image a single plane of the object from 3D tomographic data obtained in a single plane. The motivation for the application of 2D models is their advantage in speed and memory requirements. We found that the difference in the measurement data between 2D and 3D models depends greatly on the measurement type used, giving a much better agreement for mean time-of-flight data than for dc intensity data. Image artifacts that are due to data model mismatches can therefore be significantly reduced by use of mean time data.     

Determination of time-of-flight surfaces using the method of moments [US imaging

To produce an image from backscattered signals requires a knowledge of the time of flight from each source to each sensor in a transducer array. The authors reduced the determination of the rectangular coordinates of a new point on any time-of-flight surface, which requires finding the square root of the sum of squares, to the time of a single addition. To do this, the time-of-flight surface was represented by a two-dimensional, positive-integer-degree polynomial and then that polynomial was implemented in its forward-difference form. Two solutions for such a polynomial were found using the method of moments. A minimum-mean-square-error constraint yields polynomial coefficients from a numeric evaluation of the moments of arbitrary surfaces over rectangular regions, and an analytical solution for moments of time-of-flight surfaces over sector-shaped regions. For a 7x6-cm region at a minimum range of 4 cm centered in a 74 degrees sector, the maximum error for a second-degree polynomial was 0.30% of the average time of flight over the region for the numeric solution and 0.32% for the analytic solution, assuming a 1500-m/s background velocity.     

Synthesis and characterization of FeNi/polymer nanocomposites

Alloyed spherical FeNi-polymer nanocomposites were prepared via wet chemical method using hydrazine as a reducing agent and polymers (PVP and PEG) as reducing and stabilizing agent. Structural studies performed using XRD and TEM shows uniform dispersion of fine FeNi nanocrystallites in nanocomposite particles. The size and thermal stability of FeNi-polymer nanocomposite particles prepared under same reaction condition was found to be dependent on the type and the molecular weight of the polymer used. However, the magnetic properties of nanocomposite particles were not influenced by the polymers. The study highlights subtle differences in using polymers during the synthesis of alloyed nanocomposite particles.     

Contribution of tomato phenolics to suppression of COX-2 expression in KB cells

Tomatoes, which are consumed worldwide, contain abundant phenolics. The objective of this study was to understand the suppression effect of phenolics in fresh and heated tomatoes on the expression of cyclooxygenase 2 (COX-2). Both small and big tomatoes of fresh or heated (in boiling water for 30 min) treatments were used. Sephadex LH-20 gel was used to separate the noncondensed tannin containing and the condensed tannin containing fractions from the crude phenolic extracts of tomatoes. The condensed tannin containing fraction was rich in condensed tannins and simple phenolics. The noncondensed tannin containing fraction contained abundant nontannin flavans. This study explored the effect of tomato phenolic extracts on the regulation of 12-o-teradecanoylphorbol-13-acetate (TPA)-induced inflammatory responses in KB cells. HPLC showed that tomato phenolic profiles were similar between small and big tomatoes either by fresh or heated treatment. Fresh tomato extracts had 70.8 +/- 4.8% (mean +/- SD) noncondensed tannin containing polyphenols (6.68 +/- 0.09 mg/g dry weight), 27.4 +/- 6.9% condensed tannin containing polyphenols (3.52 +/- 0.24 mg/g dry weight), and 1.7 +/- 0.6% other residues. Instead, heated tomato had 53.3 +/- 4.3% noncondensed tannin containing polyphenols (2.70 +/- 0.20 mg/g dry weight), 24.2 +/- 1.7% condensed tannin containing polyphenols (7.37 +/- 0.03 mg/g dry weight), and 22.5 +/- 4.8% other residues. Cell studies showed that phenolic extracts of heated tomatoes resulted in increased suppression of COX-2 expression compared with that of fresh tomato. Noncondensed tannin containing fraction of fresh tomato greatly suppressed COX-2 expression (P < 0.05) that compared to the negative control, but both noncondensed tannin containing and condensed tannin containing fractions of heated tomatoes showed suppression on COX-2 expression. These results suggest that tomato phenolics may play an important role in the chemoprevention of cancer.     

Relatedness of medically important strains of Saccharomyces cerevisiae as revealed by phylogenetics and metabolomics

Ten medically important Saccharomyces strains, comprising six clinical isolates of Saccharomyces cerevisiae and four probiotic strains of Saccharomyces boulardii, were characterized at the genetic and metabolic level and compared with non-medical, commercial yeast strains used in baking and wine-making. Strains were compared by genetic fingerprinting using amplified fragment length polymorphism (AFLP) analysis, by ribosomal DNA ITS1 sequencing and by metabolic footprinting using both direct injection mass spectrometry (DIMS) and gas chromatography-time of flight-mass spectrometry (GC-ToF-MS). Overall, the clinical isolates fell into different groupings when compared with the non-medical strains, with good but not perfect correlation amongst strains at both the genetic and metabolic levels. Probiotic strains of S. boulardii that are used therapeutically to treat human gastro-intestinal tract disorders showed tight clustering both genetically and metabolically. Metabolomics was found to be of value both as a taxonomic tool and as a means to investigate anomalous links between genotype and phenotype. Key discriminatory metabolites were identified when comparing the three main groups of clinical, probiotic and non-medical strains and included molecules such as trehalose, myo-inositol, lactic acid, fumaric acid and glycerol 3-phosphate. This study confirmed the link between a subset of clinical isolates and baking or probiotic strains but also highlighted that in general the clinical strains were more diverse at both the genomic and metabolic levels.     

Electrolytic methanogenic-methanotrophic coupling for tetrachloroethylene bioremediation: proof of concept

Coupling of methanogenic and methanotrophic catabolisms was performed in a single-stage technology equipped with a water electrolysis cell placed in the effluent recirculation loop. The electrolysis-generated hydrogen served as an electron donor for both bicarbonate reduction into CH4 and reductive dechlorination, while the O2 and CH4, supported the cometabolic oxidation of chlorinated intermediates left over by the tetrachloroethylene (PCE) transformation. The electrolytical methanogenic/methanotrophic coupled (eMaMoC) process was tested in a laboratory-scale setup at PCE loads ranging from 5 to 50 micromol/L(rx) x d (inlet concentrations from 4 to 11 mg/L), and at various hydraulic residence times (HRT). Degradation followed essentially a reductive dechlorination pathway from PCE to cis-1,2-dichloroethene (DCE), and an oxidative pathway from DCE to CO2. PCE reductive dechlorination to DCE was consistently over 98% while a maximum oxidative DCE mineralization of 89% was obtained at a load of 4.3 micromol PCE/ L(rx) x d and an HRT of 6 days. Controlling dissolved oxygen concentrations within a relatively low range (2-3 mg/L) seemed instrumental to sustain the overall degradation capacity. Degradation kinetics were further evaluated: the apparent half-saturation constant (K(s)) had to be set relatively high (29 microM) for the simulated data to best fit the experimental ones. In spite of such kinetic limitations, the eMaMoC system, while fueled by water electrolysis, was effective in building and sustaining a functional methanogenic/methanotrophic consortium capable of significant PCE mineralization in a single-stage process. Hence, degradation standards are within reach so long as the methanotrophic DCE-oxidizing potential, including substrate affinity, are optimized and HRT accordingly adjusted.     

Soil chamber method for determination of drip-applied fumigant behavior in bed-furrow agriculture: application to chloropicrin

To overcome the environmental impacts of soil fumigant use, emission reduction strategies such as tarping can be adopted. There is a need to experimentally quantify the effectiveness of such strategies, preferably in a low-cost manner. We report the design and initial testing of a laboratory soil chamber approach for quantifying the soil distribution and emissions of fumigants from bed-furrow agricultural systems. As far as possible, field conditions (e.g., soil type, bulk density, moisture content temperature) were maintained in the experiments. In studying the drip application of chloropicrin using this system, very good data reproducibility was observed between replicates, allowing confidence in the experimental design. For control chambers, high emissions, around 60% (of the total added), were observed due to the near-surface (5 cm depth) application. When the soil beds were tarped using high-density polyethylene (HDPE) or semi-impermeable film (SIF), emissions were reduced to around 40% due to an accumulation of chloropicrin below the tarp. The approach offers an inexpensive potential alternative to studying fumigant emissions from bed-furrow systems in the field and suggests that less permeable tarps would be required to drastically reduce chloropicrin emissions.     

The histamine H1 receptor is not involved in local control of mammary blood flow in dairy cows

Low concentrations of the essential amino acid histidine in circulation have been shown to increase mammary blood flow and it has been suggested that this effect is mediated by histamine. The hypotheses tested in this experiment were that interstitial histamine concentrations in the mammary gland are related to arterial His concentrations and that mammary blood flow is reduced by extracellular histamine via H₁ receptors. The hypotheses were tested by infusing saline or chlorpheniramine, a blocker of the H₁ histamine receptor, into the arterial supply of the mammary glands of lactating cows infused with 44 g h of amino acid mixtures with or without His for 10 h. Infusates were administered in a 2 × 2 factorial arrangement within a 4 × 4 Latin square to 4 multiparous Holstein cows in mid lactation. Exclusion of His from the infusate decreased protein content in milk from the infused udder half from 3.98 to 3.77%, and increased arterial α;-aminonitrogen concentration from 3.2 to 3.4 mM. Neither the decreased arterial His concentration nor the H₁ blocker affected plasma flow to the infused udder half. We conclude that histamine is not involved in the regulation of mammary blood flow. The H₁ blocker decreased milk production in the infused udder half from 4.6 to 3.5 kg without affecting protein, fat, and lactose percentages, suggesting an inhibition of milk ejection. Cows on chlorpheniramine ate less feed during the infusion than saline-infused cows, which resulted in lower arterial concentrations and mammary uptakes of acetate. The efficiency of plasma triacylglycerol uptake across the mammary glands was decreased by chlorpheniramine but net uptake of long-chain fatty acids was not affected. The mechanism by which an amino acid deficiency influences mammary blood flow does not involve histamine signaling through the H₁ receptor and remains unidentified.