Using the POD sampler for quantitative diffusive (passive) monitoring of volatile and very volatile organics in ambient air: Sampling rates and analytical performance.

POD diffusive samplers loaded with Carbopack X and Carbograph 5TD were exposed to certified calibration mixtures containing a total of 110 different ozone precursor and air toxic compounds. Constant sampling rates were identified for 39 ozone precursors and 33 air toxics. As 9 of these compounds were included in both mixtures, this meant a total of 63 different volatile and very volatile compounds were sampled using the POD with overall expanded uncertainties below 30 % for the sampling rate associated with the whole range of sampling times from 2 to 24 h. Carbograph 5TD exhibited superior performance for diffusive sampling of oxygenated and halogenated compounds in the air toxics mixture, while Carbopack X showed higher sampling efficiencies for aliphatic and aromatic hydrocarbons, as well as halogenated compounds derived from benzene and C2 carbon number hydrocarbons. A model has been developed and applied to estimate sampling rates, primarily for the more volatile and weakly adsorbed compounds, as a function of the collected amount of analyte and the exposure time. For an additional 9 ozone precursors on Carbopack X, and 11 air toxics on Carbograph 5TD, the expanded uncertainties of modelled sampling rates were reduced to below 30 % and have a significantly reduced uncertainty compared to those associated with an averaged sampling rate. The paper provides Freundlich's isotherm parameters for the estimated (modelled) sampling rates and defines a pragmatic approach to their application. It does so by identifying the best sampling time to use for the expected exposure concentrations and associated analyte masses. This allows for expansion of the sampling concentration range from hundreds ng m-3 to mg m-3, while avoiding saturation of the adsorbent. Finally, field measurement comparisons of POD samplers, pumped tube samplers and online gas chromatography (GC), for sampling periods of 3 and 7 days in a semi-rural background area, showed no significant differences between reported concentrations.

Modelling and optimization of factors influencing adsorptive performance of agrowaste-derived Nanocellulose Iron Oxide Nanobiocomposites during remediation of Arsenic contaminated groundwater.

Nanocellulose Iron Oxide Nanobiocomposites (NIONs) were synthesized from rice husk and sugarcane bagasse derived nanocelluloses for adsorptive removal of arsenic and associated contaminants present in groundwater samples. These NIONSs were superparamagnetic, hence magnetically recoverable and demonstrated promising recyclability. Synthesis of NIONs was confirmed by Transmission electron microscopy (TEM), X-Ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopic (XPS). FTIR and XPS data together with adsorption kinetics provide insights into probable adsorption mechanism of Arsenic by NIONs. The experimental conditions for 10 different variants were modelled using response surface methodology (RSM) based on central composite design (CCD), considering the parameters; adsorbate dosage, adsorbent dosage, pH and contact time. The results identified the best performing variants and the optimal conditions for maximal absorption (~99%). These results were validated using a three-layer feed-forward Multilayer Perceptron (MLP) based Artificial Neural Network (ANN) model. Both RSM and ANN chemometric models were in close conformity for optimized conditions of highest adsorption by specific variants. The standardized conditions were used to expand the study to field-based arsenic contaminated groundwater samples and their performance to commercial adsorbents. NIONs show promising commercial potential for water remediation applications due to their high adsorptive performance, magnetic recoverability and recyclability.

Sorbitol pathway: presence in nerve and cord with substrate accumulation in diabetes.

Glucose, sorbitol, fructose, and inositol are present in peripheral nerve and spinal cord. Marked elevation of these substances occurs in these tissues in mildly diabetic animals. These alterations provide biochemical mechanisms which could be significant in the etiology of diabetic neuropathy.

[A simple method of synthesis of triterpene glycosides similar to glycyrrhizic acid and their hepatoprotective activity in vitro].

A simplified method of synthesis of triterpene l,2-trans-glycosides was developed using the glycosylation of glycyrrhetic acid (GLA) and 18,19-dehydro-GLA by beta-pyranose peracetates in the presence of SnCl(4) and molecular sieves 4 A. The synthesized glycosides exhibited hepatoprotective activity toward the human hepatoma HepG2 cell line on the model of alcohol hepatitis and decreased the level of TNF-alpha protein.

Gene Discovery for Synthetic Biology: Exploring the Novel Natural Product Biosynthetic Capacity of Eukaryotic Microalgae.

Eukaryotic microalgae are an incredibly diverse group of organisms whose sole unifying feature is their ability to photosynthesize. They are known for producing a range of potent toxins, which can build up during harmful algal blooms causing damage to ecosystems and fisheries. Genome sequencing is lagging behind in these organisms because of their genetic complexity, but transcriptome sequencing is beginning to make up for this deficit. As more sequence data becomes available, it is apparent that eukaryotic microalgae possess a range of complex natural product biosynthesis capabilities. Some of the genes concerned are responsible for the biosynthesis of known toxins, but there are many more for which we do not know the products. Bioinformatic and analytical techniques have been developed for natural product discovery in bacteria and these approaches can be used to extract information about the products synthesized by algae. Recent analyses suggest that eukaryotic microalgae produce many complex natural products that remain to be discovered.

The GPI biosynthetic pathway as a therapeutic target for African sleeping sickness.

African sleeping sickness is a debilitating and often fatal disease caused by tsetse fly transmitted African trypanosomes. These extracellular protozoan parasites survive in the human bloodstream by virtue of a dense cell surface coat made of variant surface glycoprotein. The parasites have a repertoire of several hundred immunologically distinct variant surface glycoproteins and they evade the host immune response by antigenic variation. All variant surface glycoproteins are anchored to the plasma membrane via glycosylphosphatidylinositol membrane anchors and compounds that inhibit the assembly or transfer of these anchors could have trypanocidal potential. This article compares glycosylphosphatidylinositol biosynthesis in African trypanosomes and mammalian cells and identifies several steps that could be targets for the development of parasite-specific therapeutic agents.

A comparison by magnetic circular dichroism of compound X and compound II of horseradish peroxidase.

The chlorite product of horseradish peroxidase, compound X, is shown by magnetic circular dichroism (MCD) spectroscopy in the temperature range 1.6-50 K to have a very similar haem structure to compound II under the same conditions (pH 10.7). Both are concluded to contain the Fe(IV) = 0 group. The MCD spectrum also detects an unusual species, absorbing at wavelengths between 600 and 750 nm, that has magnetic properties different from those of the ferryl haem group. It is suggested that this is a species at the same oxidation level as ferryl haem but with the porphyrin ring having suffered a one-electron oxidation, i.e. [Fe(III) P.+].

N-Substituted analogues of S-nitroso-N-acetyl-D,L-penicillamine: chemical stability and prolonged nitric oxide mediated vasodilatation in isolated rat femoral arteries.

Previous studies show that linking acetylated glucosamine to S-nitroso-N-acetyl-D,L-penicillamine (SNAP) stabilizes the molecule and causes it to elicit unusually prolonged vasodilator effects in endothelium-denuded, isolated rat femoral arteries. Here we studied the propanoyl (SNPP; 3 carbon side-chain), valeryl (SNVP; 5C) and heptanoyl (SNHP; 7C) N-substituted analogues of SNAP (2C), to further investigate other molecular characteristics that might influence chemical stability and duration of vascular action of S-nitrosothiols. Spectrophotometric analysis revealed that SNVP was the most stable analogue in solution. Decomposition of all four compounds was accelerated by Cu(II) and cysteine, and neocuproine, a specific Cu(I) chelator, slowed decomposition of SNHP. Generation of NO from the compounds was confirmed by electrochemical detection at 37 degrees C. Bolus injections of SNAP (10 microl; 10(-8)-10(-3) M) into the perfusate of precontracted, isolated rat femoral arteries taken from adult male Wistar rats (400-500 g), caused concentration-dependent, transient vasodilatations irrespective of endothelial integrity. Equivalent vasodilatations induced by SNVP and SNHP were transient in endothelium-intact vessels but failed to recover to pre-injection pressures at moderate and high concentrations (10(-6)-10(-3) M) in those denuded of endothelium. This sustained effect (> 1 h) was most prevalent with SNHP and was largely reversed by the NO scavenger, haemoglobin. We suggest that increased lipophilicity of SNAP analogues with longer sidechains facilitates their retention by endothelium-denuded vessels; subsequent slow decomposition within the tissue generates sufficient NO to cause prolonged vasodilatation. This is a potentially useful characteristic for targeting NO delivery to areas of endothelial damage.

Conjunctival capillary fragility: a preliminary study.

Conjunctival capillary fragility (CCF) and skin capillary fragility (SCF) were studied by a negative-pressure suction cup method in 25 normal subjects and 38 diabetic patients with diabetic retinopathy. The CCF was significantly higher (P less than .001) in patients with diabetic retinopathy than in normal subjects; there was no significant difference in the SCF.

Synthesis and 1H NMR characterization of the six isomeric mono-O-sulfates of 8-methoxycarbonyloct-1-yl O-beta-D-galactopyranosyl-(1-->4)-2-acetamido-2-deoxy-beta-D-glucopyran oside.

All six isomeric mono-O-sulfates of beta-D-Galp-(1-->4)-beta-D-GlcpNAc-O-(CH2)8COOMe (LacNAc-MC) have been chemically synthesized and characterized by high resolution 1H NMR spectroscopy. Sulfation causes characteristic substitution-site-specific downfield shifts of 1H NMR signals. The 4C1 chair conformation of both pyranose residues of LacNAc are unaffected by mono-O-sulfation, and, with the exception of the 3-O-sulfate derivative, glycosidic torsion angles are also unaffected.

Isolation and partial characterisation of ACV synthetase from Cephalosporium acremonium and Streptomyces clavuligerus. Evidence for the presence of phosphopantothenate in ACV synthetase.

delta-(L-alpha-Aminoadipoyl)-L-cysteinyl-D-valine (ACV) synthetase was isolated and partially characterised from Cephalosporium acremonium CO728 and Streptomyces clavuligerus. The purification procedure resulted in a 745- and 277-fold increase in specific enzyme activity, respectively. Both enzymes had similar apparent molecular masses of ca. 300 kdaltons by SDS-polyacrylamide electrophoresis, under reducing and denaturing conditions, and in excess of 600 kdaltons in the native state by gel filtration. Attempts to obtain an N-terminal amino acid sequence of ACV synthetase from C. acremonium were unsuccessful, hence internal amino acid sequence data were obtained after tryptic digestion of the protein. Phosphopantothenic acid was shown to be associated with the enzyme from both sources, which suggests the possible involvement of pantothenate as a 'swinging arm' in the formation of the tripeptide ACV.

Polycyclic aromatic hydrocarbons in central London air during 1991 and 1992.

The results of monitoring for 18 polycyclic aromatic hydrocarbons (PAH) at Exhibition Road, London, UK during the period from January 1991 to September 1992 are presented. Although both particulate and gaseous PAH were analysed, the results are expressed as total PAH. The PAH measurements are complemented by the simultaneous monitoring of a range of air quality variables. These parameters have been subjected to correlation analysis and the dependence on motor vehicle emissions for many of the PAH species is inferred. The majority of the PAH displayed higher annual mean concentrations during 1991 than previous measurements taken at the same site in 1987. The impact of motor vehicle emission legislation, the increased use of unleaded petrol and the rise in the use of diesel powered motor vehicles are all discussed in the context of the presented results. A pollution event during December 1991 caused significantly increased PAH concentrations. A comparison with PAH data from another site in London indicates good agreement between the two sets of data.

Carcass characteristics and optimal slaughter weights in four breeds of sheep.

Wether lambs from four breeds, Rambouillet (n = 38), Targhee (46), Columbia (38), and Polypay (38), were used to estimate an optimal slaughter weight for lean lamb production. Wethers, weaned at an average of 105 d of age and 38.5 kg, had ad libitum access to a finishing diet of 85% barley grain and 15% pelleted alfalfa and were slaughtered at weights ranging from 39 to 70 kg. Fat, protein, moisture, and ash percentages were determined on fat and lean from 7-rib racks. Optimal slaughter weight was estimated by using carcass backfat depth or extracted fat in the rack as dependent variables in linear equations. An acceptable lean lamb carcass was defined to have 2.5 to 6.5 mm of backfat depth and 26 to 40% rack chemical fat. On a weight-constant basis Columbia lambs were less physiologically mature than the other breeds, having less (P < .05) kidney and pelvic fat and a lower rack fat percentage. Targhee, Rambouillet, and Polypay wethers were similar in carcass fat and protein composition at a constant slaughter weight. Optimal slaughter weights for certified lean lamb carcasses of Targhee, Rambouillet, and Polypay wethers were 45 to 47 kg, resulting in a Choice quality grade and a 2.7 yield grade. The optimal weight for Columbia was heavier, between 45 and 55 kg, producing a Choice quality grade and a 2.4 yield grade. The derived optimal slaughter weights are limited to the populations sampled and may not be specific to other populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of spray-chilling on quality of beef from lean and fatter carcasses.

Carcasses from five trim cows and five choice steers were used to study the effects of spray-chilling on cooler shrink, chill rate, purge loss from vacuum-packaged cuts, cook loss, shear values and bacterial growth. Spray-chilling reduced cooler shrink but had no effect on chill rate, purge loss from vacuum-packaged cuts, cook loss or shear values. Aerobes, facultative anaerobes, aerobic psychrotrophs, facultative anaerobic psychrotrophs and lactic acid bacteria all tended to be higher on rounds from spray-chilled sides. Leaner (and lighter) cow carcasses chilled faster and had lost a higher percentage of their weight at 24 h than fatter and heavier steer carcasses. The leaner carcasses had higher bacterial counts initially and throughout storage. This difference may have been due to differences in the level of initial contamination during dressing and not due to the carcasses' leanness. Purge-weight loss for each carcass increased and cooking weight loss decreased with increased storage times, making the total weight loss from meat aged 5 vs 10 wk similar.

Intramuscular collagen characteristics of ram, wether, and zeranol-implanted ram lambs.

Eighteen spring-born Columbia ram, wether, and zeranol-implanted ram lambs were studied to determine the influence of castration or zeranol implants on intramuscular collagen (IMC) properties and muscle shear force values. Warner-Bratzler shear force values for longissimus muscle were greatest for ram lambs, intermediate for implanted rams, and least for wethers (P < .05). Nonreducible collagen crosslink concentration was greater in IMC of rams and implanted rams (P < .05). The IMC from rams compared with that from wethers contained proportionately more Type III than Type I collagen (P < .05); values for implanted rams were intermediate. Heat-soluble muscle collagen concentration was greater for rams and implanted rams than for wethers (P < .05); however, insoluble collagen concentration did not differ by treatment. Muscle collagen concentrations were not different for rams, wethers, or implanted rams. Increased shear force values in rams were associated with elevated collagen crosslink concentration and increased proportion of Type III collagen. Greater concentration of soluble collagen in ram IMC neither diminished nor diluted IMC crosslinking. The proportion of heat-labile collagen in the fractions did not reflect the IMC crosslinking profile for ram and wether lambs. Zeranol implantation modified IMC characteristics of rams such that shear force values and some collagen properties were similar to those of wethers.

Collagen characteristics of skin, fell, and epimysium from rams, wethers, and zeranol-implanted ram lambs.

Eighteen spring-born Columbia ram, wether, and zeranol-implanted ram lambs were examined to determine the influence of castration or zeranol implantation on collagen characteristics of skin, fell, and epimysium and possible relationships between collagen properties of each tissue and difficulty of pelt removal. Pelt removal force was lower in wethers than in rams (P < .05) and intermediate for zeranol-implanted rams. Collagen concentration in skin of rams was greater (P < .05) than that in wethers or implanted rams, but percentage of heat-soluble collagen in skin was higher in implanted rams. Percentage of type III collagen in skin was highest in rams and lowest in wethers (P < .05); that in the skin of implanted rams was intermediate. The fell of wethers contained a higher (P < .05) collagen concentration, higher insoluble collagen amount, and lower percentage of soluble collagen than that of rams or implanted rams. The fell had a lower percentage of type III collagen than that of rams (P < .05). Epimysium collagen concentration of rams and wethers was higher (P < .05) than that of implanted rams; however, percentage of soluble collagen was higher for the implanted rams than for the other classes. Type III collagen percentage in the epimysium did not differ by animal class (P < .05). Zeranol-implanted ram lambs had a higher percentage of soluble collagen in all tissues examined than did non-implanted rams and force required for pelt removal was reduced in implanted rams.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of breed and intake level on growth and feed efficiency in ram lambs.

Effects of breed and intake level on growth and feed efficiency in ram lambs were tested with 52 Rambouillet, 46 Dorset and 53 Finnish Landrace (Finn) rams. Rams were individually fed at 100, 85 or 70% of ad libitum or at maintenance. The experimental diet contained 79% digestible dry matter (DM), 3.28% N and 2.95 Mcal metabolizable energy/kg DM. Rams were serially slaughtered every 35 d for 175 d. The efficiency of deposition of body weight, protein, energy and trimmed cuts was determined by breed and intake level over constant time, weight, fat and maturity intervals. Ranking of the breeds for feed efficiency depended upon both the interval and the criterion of evaluation. Efficiency of protein and trimmed cut gain was positively related to mature size in the time and weight intervals, but all differences in efficiency were small in the fat or maturity intervals. Gross energetic efficiency did not differ greatly among breeds in any interval. Dorsets appeared to have a somewhat greater propensity to fatten than the other breeds and to be less able to retain N at a fixed N intake. In the constant time interval, maintenance requirements were estimated to be 115 kcal/kg.75, and the estimated partial efficiencies of energy deposition in fat and protein were .49 and .26, respectively.

Palatability of wethers fed an 80% barley diet processed at different ages and of yearling wethers grazed on native range.

Seasonal availability of lamb in the Western United States contributes to a large fluctuation in lamb supply and value. However, alternatives to fall marketing may not be practical unless palatability traits are acceptable. A 3-yr study was conducted to investigate 1) the effects of slaughter age (7 to 8; 10 to 11; or 14 to 15 mo) on carcass and palatability characteristics of wethers fed an 80% barley diet (Exp. 1); and 2) the effects of finishing on range or on an 80% barley diet on carcass and palatability traits of 14- to 15-mo-old wethers (Exp. 2). In Exp. 1, no differences (P = .27) were detected in flavor intensity or longissimus muscle area among slaughter age groups, but fat depth was greater (P < .05) for 7- to 8-mo-old wethers than for 10- to 11- or 14- to 15-mo-old wethers. Year x slaughter age interactions were detected (P < .10) for hot carcass weight, Warner-Bratzler shear value, body wall thickness, and percentage kidney fat. Hot carcass weight was greater (P < .05) for 14- to 15-mo-old wethers than for both groups of younger wethers in yr 1, did not differ (P = .53) among slaughter ages in yr 2, and was greater (P < .05) for 10- to 11- than for 14- to 15-mo-old wethers in yr 3. Warner-Bratzler shear values did not differ (P > .10) among slaughter ages in yr 1 and 3, but shear values for 14- to 15-mo-old wethers were greater (P < .05) than for both younger slaughter age groups in yr 2. Percentage kidney fat was lower (P < .05) for 14- to 15- than for 7- to 8-mo-old wethers in all years. In Exp. 2, flavor intensity of the meat did not differ (P = .35) between finishing systems, but longissimus muscle area was greater (P = .02) for range-finished wethers than for wethers fed an 80% barley diet. Year x finishing treatment interactions were detected (P < .10) for shear values, body wall thickness, percentage kidney fat, and fat depth. Shear values were greater (P = .10) for range-finished wethers than for wethers fed an 80% barley diet in yr 1, but did not differ (P > .55) in yr 2 and 3. Body wall and fat measurements were greater (P < .10) for wethers fed an 80% barley diet than for range-finished wethers in all years except yr 3, when fat depth did not differ (P = .47). Overall, slaughtering wethers fed an 80% barley diet or range-finished wethers at older ages produced acceptable carcasses with desirable meat palatability traits.

Growth and slaughter characteristics of ram and wether lambs implanted with zeranol.

Forty-nine Columbia ram and wether lambs born in April 1990 and 46 born in April 1991 were studied to determine the effects of zeranol implants on growth, difficulty of pelt removal, and carcass characteristics. Implanting ram and wether lambs once (1990) or twice (1991) with 12 mg of zeranol did not change live weight or ADG but gain/feed decreased (P < .05) in ram lambs slaughtered at approximately 50 kg. Testes weight was reduced approximately 50% by implanting. Two implants reduced (P < .05) the force needed to pull the pelt from the hind legs of ram lambs, but implanting tended to increase the force required to pull the pelt from wether lambs. Data for pelt weight, force required to pull the pelt, percentage of the carcass in the shoulder or splenius muscle, and Warner-Bratzler shear values showed that zeranol implants resulted in ram lambs becoming more like wethers and wether lambs becoming more like rams. Implanting with zeranol did not affect closure of the metacarpal growth plate in ram or in wether lambs. Difficulty of pelt removal can be reduced by implanting ram lambs with 12 mg of zeranol at approximately 114 d of age and reimplanting zeranol 28 d later.

Effects of maternal undernutrition during early pregnancy on growth, muscle cellularity, fiber type and carcass composition in lambs.

Seventy-two Rambouillet ewes were fed one of two different levels of energy and protein during gestation to determine the effects of maternal undernutrition on growth and development in their offspring. Levels of energy and protein for the two groups of ewes were: 70% of National Research Council (NRC) requirements 30 d prior to breeding and the first 100 d of gestation and then alfalfa hay fed at 70% of the average consumed by group 2, and 100% of NRC requirements 30 d prior to breeding and throughout gestation. Dissection data from the leg and muscle characteristics were recorded for each lamb. Neither dissected muscle and fat percentages nor proximate analyses of dissected muscles was influenced by ewe undernutrition during early pregnancy. However, the reduced conception rate, increased embryonic/fetal mortality, decreased birth weights and increased lamb mortality resulted in a severe reduction in kilograms of lamb per ewe bred. Feeding ewes 70% of NRC requirements during gestation resulted in lambs with heavier semitendinosus muscle weights, larger muscle fiber diameters and shorter sarcomere lengths than in lambs from adequately fed ewes. No influence of ewe diet, birth type or sex was observed for proportions of muscle fiber type (beta R, alpha R or alpha W). Therefore, low level feeding of ewes during early gestation had no detrimental effects on the carcass or muscle fiber characteristics of their lambs at slaughter.