Lectin-binding pattern of the Senegalese sole Solea senegalensis oogenesis

The glycoconjugate pattern of developing ovarian follicles in wild and cultured Senegalese sole Solea senegalensis was investigated by means of lectin histochemistry. Ovaries from cultured fish contained oocytes up to the late vitellogenic stage, whereas they reached the hydration stage in wild specimens. The follicular cells bound MAL II, SBA, HPA, DBA, Con A, KOH-sialidase (K-s)-WGA, GSA I-B(4) in the late vitellogenic stage, and in wild fish also SNA and K-s-PNA, whereas in the hydration stage SBA, HPA, DBA, and GSA I-B(4) only. The zona radiata reacted with SBA, HPA, DBA, Con A, and GSA I B(4) in the late vitellogenic stage and in cultured fish also with UEA I, whereas in the hydration stage it stained with SBA only. The cortical alveoli bound SBA, HPA, RCA(120) during the late vitellogenic stage, also SNA, PNA, K-s-PNA, GSA I-B(4) in cultured fish, DBA, and K-s-WGA in wild ones which stained with SBA, HPA, and GSA I-B(4) in the hydrated stage. The yolk reacted with Con A in the late vitellogenic oocytes, and also with MAL II, SNA, K-s-PNA, SBA, HPA, K-s-WGA, GSA I-B(4), UEA I in the hydrated ones. From perinucleolus to late vitellogenic stages, the oocyte nucleoplasm bound Con A, GSA I-B(4), GSA II, UEA I, and in wild fish also MAL II, SNA, LTA but only GSA I-B(4) reactivity in the early maturation stage. These findings demonstrate that the glycan pattern of fish ovarian follicles changes during the maturative stages and that it is affected by culture-rearing conditions.     

Sample preparation method for visualization of nanoparticulate captured on mixed cellulose ester filter media by enhanced darkfield microscopy and hyperspectral imaging

A significant hurdle in conducting effective health and safety hazard analysis and risk assessment for the nanotechnology workforce is the lack of a rapid method for the direct visualization and analysis of filter media used to sample nanomaterials from work environments that represent potential worker exposure. Current best‐known methods include transmission electron microscopy (TEM) coupled with energy dispersive x‐ray spectroscopy (EDS) for elemental identification. TEM‐EDS is considerably time‐, cost‐, and resource‐intensive, which may prevent timely health and safety recommendations and corrective actions. A rapid screening method is currently being explored using enhanced darkfield microscopy with hyperspectral imaging (EDFM‐HSI). For this approach to be effective, rapid, and easy, sample preparation that is amenable to the analytical technique is needed. Here, we compare the sample preparation steps for mixed cellulose ester (MCE) filter media specified in NIOSH Method 7400—Asbestos and Other Fibers by Phase Contrast Microscopy (PCM)—against a new method, which involves saturation of the filter media with acetone. NIOSH Method 7400 was chosen as a starting point since it is an established technique for preparing transparent MCE filters for optical microscopy. Limitations in this method led to the development and comparison of a new method. The new method was faster, easier, and rendered filters more transparent, resulting in improved visualization and analysis of nanomaterials via EDFM‐HSI. This new method is suitable for a rapid screening protocol due to its speed, ease of use, and the improvement in image acquisition and analysis.     

Far-field plasmonic resonance enhanced nanoparticle image velocimetry within a microchannel

In this paper, a novel far-field plasmonic resonance enhanced nanoparticle-seeded particle image velocimetry has been demonstrated to measure the velocity profile in a microchannel. Chemically synthesized silver nanoparticles have been used to seed the flow in the microchannel. By using discrete dipole approximation, plasmonic resonance enhanced light scattering has been calculated for spherical silver nanoparticles with diameters ranging from 15 to 200 nm. Optimum scattering wavelength is specified for the nanoparticles in two media: water and air. The diffraction-limited plasmonic resonance enhanced images of silver nanoparticles at different diameters have been recorded and analyzed. By using standard particle image velocimetry techniques, the velocity profile within the microchannel has been determined from the images.     

Distribution of FMRFamide-like immunoreactivity in the alimentary tract and hindgut ganglia of the barnacle Balanus amphitrite (Cirripedia, Crustacea)

In this study, the presence and distribution of FMRFamide-like immunoreactivity in the alimentary tract of barnacle Balanus amphitrite were investigated. A net of nerve fibers strongly immunoreactive to FMRFamide-like molecules was localized in the posterior midgut and hindgut. Positive varicose nerve terminals were also localized close to the circular muscle cells and, in the hindgut, close to the radial muscular fibers. Besides this nerve fibers network, one pair of contralateral ganglia was localized in the hindgut, each of them constituted by two strongly FMRFamide-labeled neurons and one nonlabeled neuron. Their immunoreactive axons directed toward the hindgut and posterior midgut suggest an involvement of FMRFamide-like substances in adult B. amphitrite gut motility. The hindgut associated ganglia of barnacles seem to correspond to the terminal abdominal ganglia of the other crustaceans. Since they are the only residual gut ganglia in the barnacle's reduced nervous system, we can hypothesize that gut motility needs a nervous system regulation partially independent of the central nervous system.     

Graphene oxide nanosheets modified with trithiocyanuric acid for extraction and enrichment of Pb (II) and Cu (II) ions in seawater

Trithiocyanuric acid (TTC) is a robust chelating ligand for extracting divalent and univalent heavy metals from water samples. In this method, graphene oxide nanosheets (GO) was modified with TTC, to produce a new nano‐adsorbent (GO‐TTC), for extraction and preconcentration of Pb (II) and Cu (II) ions from seawater samples. The concentrated analytes were measured by a flame atomic absorption spectrometry. The detection limits of the method for Pb (II) and Cu (II) ions were 0.32 ng/mL and 0.13 ng/mL, respectively. The relative standard deviations of analytes for six successive extractions were below 1.64%. The maximum adsorption capacity of GO‐TTC for Pb (II) and Cu (II) ions was 750 µg/g and 460 µg/g, respectively. The recoveries of the spiked analytes in artificial and natural seawater samples were above 90%, pointing out that the method is not affected by the major coexisting ions in seawater matrices.     

GIS supported calculations of (137)Cs deposition in Sweden based on precipitation data

It is of interest to know the spatial variation and the amount of (137)Cs e.g. in case of an accident with a radioactive discharge. In this study, the spatial distribution of the quarterly (137)Cs deposition over Sweden due to nuclear weapons fallout (NWF) during the period 1962-1966 was determined by relating the measured deposition density at a reference site to the amount of precipitation. Measured quarterly values of (137)Cs deposition density per unit precipitation at three reference sites and quarterly precipitation at 62 weather stations distributed over Sweden were used in the calculations. The reference sites were assumed to represent areas with different quarterly mean precipitation. The extent of these areas was determined from the distribution of the mean measured precipitation between 1961 and 1990 and varied according to seasonal variations in the mean precipitation pattern. Deposition maps were created by interpolation within a geographical information system (GIS). Both integrated (total) and cumulative (decay corrected) deposition densities were calculated. The lowest levels of NWF (137)Cs deposition density were noted in north-eastern and eastern parts of Sweden and the highest levels in the western parts of Sweden. Furthermore the deposition density of (137)Cs, resulting from the Chernobyl accident was determined for an area in western Sweden based on precipitation data. The highest levels of Chernobyl (137)Cs in western Sweden were found in the western parts of the area along the coast and the lowest in the east. The sum of the deposition densities from NWF and Chernobyl in western Sweden was then compared to the total activity measured in soil samples at 27 locations. Comparisons between the predicted values of this study show a good agreement with measured values and other studies.     

Assessment of inorganic content of PM(2.5) particles sampled in a rural area north-east of Hanoi, Vietnam

Atmospheric aerosols from seven rural sites in northern Vietnam, east of Hanoi, were sampled and analyzed. The aim of the study was to evaluate trace elemental and black carbon (BC) concentrations in fine particles (PM(2.5)) and to investigate the influence of the Pha Lai power plant and other pollution sources on regional air quality. Seven measurement stations were set up at selected rural sites and a campaign consisting of 12 two-day measurement periods was conducted from the end of May until the end of October 2000. At each location a pair of samplers was installed consisting of a cyclone loaded with Teflon filters and a modified Millipore air monitoring cartridge loaded with glass fibre filters. The obtained samples were analyzed for trace elements by Energy Dispersive X-ray Fluorescence (EDXRF), while a black smoke detector was used for BC analysis. Seventeen trace elements were analyzed; Br, Ca, Cl, Cr, Cu, Fe, K, Mn, Ni, Pb, Rb, S, Se, Sr, Ti, V and Zn and their concentrations evaluated. The results showed that BC, Ca, Cl, Fe, K and S dominated in the sampled atmospheric aerosols. The measured concentrations of the potentially hazardous trace elements Cr, Mn, Ni and Pb were all below the limits defined by Vietnamese standards of ambient air quality. Statistical evaluations indicated that coal and heavy fuel oil combustion were major sources of atmospheric pollutants in the area and that biomass burning and road transport had a marked influence on regional air quality. It was concluded that the Pha Lai power plant was the major source of coal combustion emissions. Trace element emissions originating from river transportation were suggested as another major source of atmospheric pollutants. The results indicate that the elemental concentrations in PM(2.5) are strongly influenced by seasonal variations. Further measurements are required to identify the impact of long-range transported continental air masses on the air quality of the investigated rural area.     

Removal of anionic dye Congo red from aqueous solution by raw pine and acid-treated pine cone powder as adsorbent: equilibrium, thermodynamic, kinetics, mechanism and process design

Pine cone a natural, low-cost agricultural by-product in Australia has been studied for its potential application as an adsorbent in its raw and hydrochloric acid modified form. Surface study of pine cone and treated pine cone was investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The modification process leads to increases in the specific surface area and decreases mean particle sizes of acid-treated pine cone when compared to raw pine cone biomass. Batch adsorption experiments were performed to remove anionic dye Congo red from aqueous solution. It was found that the extent of Congo red adsorption by both raw pine cone biomass and acid-treated biomass increased with initial dye concentration, contact time, temperature but decreased with increasing solution pH and amount of adsorbent of the system. Overall, kinetic studies showed that the dye adsorption process followed pseudo-second-order kinetics based on pseudo-first-order and intra-particle diffusion models. The different kinetic parameters including rate constant, half-adsorption time, and diffusion coefficient were determined at different physico-chemical conditions. Equilibrium data were best represented by Freundlich isotherm model among Langmuir and Freundlich adsorption isotherm models. It was observed that the adsorption was pH dependent and the maximum adsorption of 32.65 mg/g occurred at pH of 3.55 for an initial dye concentration of 20 ppm by raw pine cone, whereas for acid-treated pine cone the maximum adsorption of 40.19 mg/g for the same experimental conditions. Freundlich constant 'n' also indicated favourable adsorption. Thermodynamic parameters such as ?G(0), ?H(0), and ?S(0) were calculated. A single-stage batch absorber design for the Congo red adsorption onto pine cone biomass also presented based on the Freundlich isotherm model equation.     

Complications with remediation strategies involving the biodegradation and detoxification of recalcitrant contaminant aromatic hydrocarbons

Environmentally persistent aromatic hydrocarbons known as unresolved complex mixtures (UCMs) derived from crude oil can be accumulated by, and elicit toxicological responses in, marine organisms (e.g. mussels, Mytilus edulis). Comprehensive two-dimensional gas chromatography time-of-flight mass-spectrometry (GC × GC-ToF-MS) previously revealed that these UCMs included highly branched alkylated aromatic hydrocarbons. Here, the effects of biodegradation on the toxicity and chemical composition of an aromatic UCM hydrocarbon fraction isolated from Tia Juana Pesado (TJP) crude oil were examined. 48 h exposure of mussels to the aromatic hydrocarbon fraction (F2) resulted in tissue concentrations of 900 µg g^− 1 (dry wt.) and ∼ 45% decrease in clearance rate. Over 90% of the hydrocarbon burden corresponded to an UCM. Following a 5 day recovery period, GC × GC-ToF-MS analysis of the tissues indicated depuration of most accumulated hydrocarbons and clearance rates returned to those observed in controls. To assess the potential of biodegradation to reduce UCM toxicity, TJP F2 was exposed to bacteria isolated from Whitley Bay, UK, for 46 days. Mussels exposed to the undegraded TJP F2 from the abiotic control exhibited a reduction in clearance rate comparable with values for the pure crude oil TJP F2. Clearance rates of mussels exposed to biodegraded TJP F2 were statistically similar to seawater controls, suggesting biodegradation had reduced the TJP F2 toxicity. GC × GC-ToF-MS analysis revealed the same compound groups in the tissue of mussels exposed to pure TJP F2, undegraded TJP F2 and biodegraded TJP F2 samples; however > 300 fewer compounds were observed in the biodegraded (954 compounds) compared to the undegraded TJP F2 (1261). The compound distributions were markedly different, possibly accounting for the decrease in toxicity. Extraction and analysis of pelleted bacterial cell material revealed that a significant proportion of the TJP F2 had adsorbed onto the cells. Thus extreme care must be taken in interpreting biodegradation data from recalcitrant UCM hydrocarbons.