Development of a benzene vapour sensor utilizing chemiluminescence on Y2O3

Chemiluminescence (CL) was observed when benzene vapour passed through the surface of Y₂O₃, TiO₂, Y₂O₃–V₂O₅, TiO₂–Y₂O₃, Y₂O₃–Cr₂O₃, Y₂O₃–Al₂O₃ and TiO₂–Al₂O₃, with air as the carrier gas. The strongest CL intensity was found with Y₂O₃ as the catalyst. A novel benzene sensor based on this kind of CL was developed. Quantitative analysis was performed at the wavelength of 425 nm. Under optimal conditions, CL intensity was directly proportional to the concentration of benzene vapour. The linear range was 4–7018 mg/m³ (r = 0.9981, n = 11), with a detection limit of 1 mg/m³ (the signal:noise ratio was 3). This gas sensor can work continuously for >80 h and has been successfully applied to the real‐time determination of benzene vapour. Copyright © 2008 John Wiley & Sons, Ltd.     

Hair concentrations of calcium, iron, and zinc in pregnant women and effects of supplementation

In this investigation, the concentration levels of hair elements of calcium, iron, and zinc were measured in pregnant women from Tianjin metropolis, China. The subjects were 93 cases of pregnant women who had been suffering from calcium, iron, or zinc deficiency judged by blood tests at the mid-term of the second trimester or early in the third trimester. Of these 93 cases, 82 subjects had their hair element levels measured when the blood tests were conducted. Then, they were supplied with mineral element nutrients of gluconic acidic zinc (noted as Zn-nutrient), gluconic acidic calcium (Ca-nutrient), or/and ferrous sulfate (Fe-nutrient) which were correspondent to the deficient element(s) for more than 2 mo before 84 subjects returned to hospital for further diagnoses and had their hair element levels measured for the second time. Finally, in the third trimester or nearparturient phase, 13 subjects had their hair element levels measured again. Except for the deficiencies of calcium, iron, or/and zinc, these subjects were all healthy without symptoms of any diseases. The concentrations of hair Ca, Fe, and Zn were measured by X-ray fluorescence (XRF) spectrometry. These concentrations of the three hair elements measured at three different times were statistically analyzed. From the analyses, it was clear that hair concentrations of Ca, Fe, and Zn could reflect the effects of supplementation. Also, the mutual resistant effects among Ca-, Fe-, and Zn-nutrients were revealed. However, by appropriate combination, the mutual resistant effects could be depressed and mutual promotional effects might be enhanced. Finally, it could be concluded that mineral element deficiencies might be convalesced by adequate compensations of mineral element nutrients.     

The effect of excitation on the rate of respiration in the liverwort Conocephalum conicum

Simultaneous measurements were taken of the electrical activity and the rate of respiration of thalli of Conocephalum conicum L. stimulated electrically and mechanically (by cutting). The measurements of the rate of respiration employed a modified Warburg apparatus for O₂ consumption and an infra-red gas analyzer with computer recording and data processing for CO₂ evolution. The action potential, produced by either a cut (a damaging stimulus) or an electrical stimulus (a non-damaging stimulus), caused a transient rise in the rate of respiration. The course of changes in the rate of respiration depends on the character of the excitation and the area of the thallus covered by it. If stimulation does not produce excitation, the increase in the rate of respiration does not take place, regardless of the magnitude and type of the stimulus applied.     

Identification of air phase retronasal and orthonasal odorant pairs

Identifications (IDs) of paired retronasal and orthonasal odorants were studied, with stimuli limited to air phase. Odorants were liquid extracts of plant materials, sold as food flavorings, matched by each subject both for retronasal-only and orthonasal-only air phase intensities and then learned to 100% correct veridical name retronasal-only and orthonasal-only IDs. Subjects were tested for ID of (a) retronasal-only and orthonasal-only odorants, (b) homogeneously paired odorant (the same odorant in retronasal and orthonasal locations), and (c) heterogeneously paired odorants (different odorants in retronasal and orthonasal locations). Paired odorants were presented in two different sequences: retronasal location odorant smelled first or orthonasal location odorant smelled first. IDs were reported after odorants were removed. Results were as follows: (a) no significant differences between correct ID of odorants when in retronasal-only versus orthonasal-only locations, although percent correct IDs were lower for half the retronasal-only location odorants; (b) correct ID of a homogeneously paired odorant equaled or exceeded its unpaired ID, with two successive, identical IDs reported on the majority of its trials; (c) with heterogeneous pairs, for all odorants when in the orthonasal location of a pair, correct ID occurred less often than when these odorants were presented orthonasal-only, but for odorants in the retronasal location, correct ID equaled or exceeded retronasal-only correct ID; and (d) perceived order of presentation of heterogeneous pairs was the reverse of the physically presented sequence for both retronasal-first and orthonasal-first conditions. The heterogeneous odorant ID outcome supports the concept that processing of retronasal and orthonasal odorants differ, and the perceived reversal of the presented sequence is in agreement with the importance of recency in odorant memory.     

O-raffinose crosslinked hemoglobin lacks site-specific chemistry in the central cavity: structural and functional consequences of beta93Cys modification

Reacting human deoxyHbA0 with oxidized raffinose (O-raffinose), a trisaccharide, results in a low oxygen affinity "blood substitute," stabilized in a noncooperative T-conformation and possesses readily oxidizable rhombic heme. In this study, we fractionated the O-raffinose-modified HbA0 heterogeneous polymer (O-R-PolyHbA0) into six distinct fractions with a molecular weight distribution ranging from 64 to approximately 600 kDa using size-exclusion chromatography (SEC). Oxygen equilibrium and kinetics binding parameters of all fractions were nearly identical, reflecting a lack of heterogeneity in ligand binding properties among O-R-PolyHbA0 species (Hill coefficient n equal to 1.0). Several mass spectrometry techniques were used to evaluate undigested and digested HbA0, O-R-PolyHbA0, and O-R-PolyHbA0 fractions. Proposed sites of intramolecular crosslinking (i.e., beta1Lys82, beta2Lys82, and beta1Val1) were not found to be the predominant site of crosslinking within the central cavity. Intermolecular crosslinking with O-raffinose results in no discernible site of amino acids modifications with the exception of beta93Cys and alpha104Cys. Based on accessible surface area (ASA) calculations in intact deoxyHbA0, slight conformational changes are required to allow for the S on alpha104Cys to be modified during the reaction with O-raffinose or its partially oxidized product(s). The stabilization of HbA0 in the T-conformation may not be a direct correlate of O-raffinose induced changes, but an indirect consequence of changing hydration in the water-filled central cavity and/or the distal heme pocket leading in the latter case to accelerated iron oxidation. Structural data presented here when taken together with the oxidative instability of O-R-PolyHbA0 may provide some basis for the reported toxicity of this oxygen carrier.     

Using multiple satellite observations to quantitatively assess and model oil pollution and predict risks and consequences to shoreline from oil platforms in the Caspian Sea

This research focused on the following objectives: (1) using satellite data to characterize the spatiotemporal distribution of anthropogenic oil spills from Oil Rocks Settlement, Chilov and Pirallahi Islands (2) stochastic modeling of the oil spill risk pose to water quality and shoreline ecosystems, and (3) validating model predictions using satellite images. 165 satellite images acquired by SENTINEL-1A, LANDSAT-8, RADARSAT, ENVISAT and ERS sensors between 1996 and 2015 were used for the detection of oil spills using object-based classification and visual interpretation. Anthropogenic hotspots were observed at three oldest oil production sites with estimated oil spilling up to 1264 m³ per day and different degrees of temporal repetition of oil spills. The largest area (5639 km²) experienced 1–10 detected oil spills, while 993 km² experienced 11–20 oil spills, 775 km² experienced 21–50 oil spills, 208 km² experienced 51–100 oil spills, and 36 km² experienced 101–150 oil spills. The majority (83% or 6157 km²) of sea surface area within the combined boundary of detected oil spills (7422 km²) had a 50% or greater chance of oil spill contamination. Approximately, 6% (44 km of 751 km) of shoreline had a 50% or greater probability of contamination with land use classes sensitive to pollution.     

Ecological risk assessment of accidental release of flowback water: A conceptual framework

The aim of the study is to conduct an ecological risk assessment of accidental release of flowback water into freshwater body. Flowback water produced from the hydraulic fracturing process has a complex combination of high concentration of salts, organic compounds and metals. The toxicity of flowback water is assessed and an exposure assessment method for the inorganic constituents of the flowback water is developed. An equation for risk is derived to characterize the risk of the flowback water to the aquatic ecology. A case study is conducted for accidental release of hydraulic fracturing flowback water in Montney unconventional play trend in northern British Columbia. The flowback water quality data for 212 wells, including the concentrations of various salt ions, metal ions, and hydrogen sulfide, is collected for the assessment. The risk quotient is found to be 0.16 (<1), proving no significant risk to the aquatic ecosystem with 90% confidence. However, the overall results of the uncertainty and scenario analysis concludes that the risk to the ecology cannot be completely overlooked. Scenario analysis was done for monthly creek discharge and a relationship between risk quotient and the ratio of spill volume to the creek discharge was derived.     

Optimization of protocols for microinjection-based delivery of cryoprotective agents into Japanese whiting Sillago japonica embryos

Microinjection has proven useful for introduction of low-permeability cryoprotective agents (CPAs) into fish eggs or embryos for cryopreservation. In this work, we examined the suitable conditions for single or combined microinjection into the perivitelline space (PS) and the yolk mass (YM) of embryos of the Japanese whiting, an alternative marine fish model for embryo cryopreservation studies. The parameters examined were injection volume, CPA type and concentration, vehicle (diluent), and suitable developmental stage. Somites and tail elongation embryos tolerated single or combined injection with 2.1 and 15.6 nl in the PS and YM, respectively, whereas earlier embryonic stages tolerated only up to 8.2 nl in the YM. The injected solutions diffused rapidly throughout the PS and YM and remained contained within each compartment unless in the case of structural damage caused by injection of larger volumes. Yamamoto solution was marginally better as a vehicle for microinjection of CPAs than fish Ringer and phosphate buffer saline whereas ¼ artificial sea water was clearly unsuitable. Ethylene glycol was well tolerated by embryos in all developmental stages whereas 1, 2-propylene glycol was suitable only for early embryonic stages. Overall, microinjection was efficient in delivering high loads of CPAs inside whiting embryos more swiftly than previously obtained for this species by immersion-based impregnation protocols. Embryos microinjected with CPAs showed a decrease in embryo nucleation temperature and an increase in chilling tolerance. CPA-microinjected embryos will provide valuable materials to optimize the remaining parameters that are critical for successful cryopreservation such as cooling and warming strategies.