Endocrine disruption in brook trout (Salvelinus fontinalis) exposed to leachate from a public refuse dump

Lake Molnbyggen was previously found to harbour a large number of sexually immature female perch (Perca fluviatilis) suffering from endocrine disruption. In an attempt to pin-point the source of the endocrine-disrupting substance(s) (EDSs), brook trout (Salvelinus fontinalis) from Vadb?cken, a stream contaminated by leachate from a public refuse dump and which empties into Lake Molnbyggen, were investigated. In addition, female perch from Lakes Yxen and Kvarntj?rn, located up-stream and down-stream of Lake Molnbyggen, were investigated. Only 16.7% of the adult female brook trout in Vadb?cken were sexually mature, associated with decreased gonadosomatic index, lower brain aromatase activity, and lower circulating levels of testosterone and 17beta-oestradiol, in comparison to female brook trout from the reference stream Bj?rntj?rnsb?cken. Male brook trout showed decreased gonadosomatic index, in addition to bile duct hyperplasia in the liver, which was also found in female brook trout livers from Vadb?cken. In Lake Molnbyggen, 57.6% of the female perch were found to be sexually immature with high frequencies of skin lesions, such as sores and fin erosion, significantly decreased gonadosomatic index, lower aromatase activity, and lower levels of testosterone and 17beta-oestradiol. No signs of reproductive disorders or endocrine disruption were seen in female perch from Lakes Yxen and Kvarntj?rn compared to female perch from the reference lake, Lake Djursj?n. Since brook trout of both sexes from Vadb?cken displayed the same kind of serious adverse impairment of gonad development and endocrine disruption as perch from Lake Molnbyggen, very strong evidence are provided that the refuse dump is the source for the responsible EDS(s), since both Vadb?cken and Lake Molnbyggen are known to be contaminated by leachate from that dump. The low levels of PAHs and PCBs in the surface sediments of Lake Molnbyggen suggest that these pollutants are not the responsible EDS(s).     

Morphology of sodium salt of calf thymus DNA on mica,alumina, and silica surfaces: Effect of solvent and drying method

ABSTRACT

Investigation of morphology of deoxyribonucleotide triphosphate (DNA) dried on different surfaces by atomic force microscopy (AFM) is important in DNA research that is focused on subjects of condensation for gene therapy, sizing, DNA mapping, and cancer examination. The solvent, the surface type, and the method of drying effect the morphology of DNA on solid surfaces. Ethanol and water were used as solvents, flat mica, silica, and alumina surfaces were used as the substrates in the present study. Different methods such as ambient air-drying, N₂-forced flow regime drying, and freeze-drying have been applied to droplets of DNA solutions in water or ethanol on the substrates. Forced flow drying regime causes nonlinear DNA attachment on the surface and self-assembly. DNA vertical distance on mica surface was found to be 6 and 1.4?nm for DNA dried in ambient air from ethanol and water solutions, respectively. It was 1.6?nm for N₂ flow drying of aqueous DNA solution on mica surface. It was 4.6, 4.6, and 1.99?nm for ambient, N₂ flow, and freeze-dried aqueous DNA on alumina surfaces, respectively. Aqueous solution of DNA dried under N₂ flow on silica surface had 0.8?nm vertical distance. The smallest standard deviation of 0.05?nm was observed for DNA dried under N₂ flow on alumina surface.     

DNA-Binding Study of Tetraaqua-bis(p-nitrobenzoato)cobalt(II) Dihydrate Complex: [Co(H2O)4(p-NO2C6H4COO)2]·2H2O

The interaction of [Co(H₂O)₄(p-NO₂C₆H₄COO)₂]^· 2H₂O with sheep genomic DNA has been investigated by spectroscopic studies and electrophoresis measurements. The interaction between cobalt(II) p-nitrobenzoate and DNA has been followed by gel electrophoresis while the concentration of the complex was increased from 0 to 14 mM. The spectroscopic study and electrophoretic experiments support the fact that the complex binds to DNA by intercalation via p-nitrobenzoate into the base pairs of DNA. The mobility of the bands decreased as the concentration of complex was increased, indicating that there was increase in interaction between the metal ion and DNA.     

Spectrally resolved cathodoluminescence analyses in the optical near-field

By implementing a scanning near-field optical microscope into the specimen chamber of a scanning electron microscope, cathodoluminescence can be locally detected in the optical near-field. The achievable spatial resolution in this set-up is only limited by the size of the aperture in a coated fibre probe and its separation from the sample, rather than by the energy dissipation volume of the primary electrons and diffusion processes of excess carriers inside the specimen. We demonstrate how electronically active defects in polycrystalline diamond can be distinguished and localized with sub-wavelength lateral resolution by spectral filtering of the cathodoluminescence signal.     

Silver and proton driven fluorescent multiple-mode molecular logic gates employing phthalocyanines

Spectral properties and switch behavior of two alkyl thia units bearing Zn (II) phthalocyanine derivatives (Pc-A and Pc-B) were investigated in solvents and in solid matrix of ethyl cellulose by means of absorption and emission spectroscopy. Fluorescence lifetime and fluorescence quantum yield values of the Zn (II) phthalocyanines were calculated. The employed phthalocyanines demonstrated multiple molecular logic gate functions operated by H⁺ and Ag⁺ ions as chemical inputs. The silver driven fluorescence modulation of the Pc-A arises from reversible variations in emission signal intensity at 717 nm. The Pc-B exhibited a similar decreasing emission response to proton and silver ions and an accompanying increasing peak yielding an isobestic point at 746 nm upon protonation. The phthalocyanine doped thin films selectively responded to silver ions in sub-nano and/or pico molar levels. Observed detection limits were 7.6 × 10⁻¹² and 2.3 × 10⁻¹¹ M for Pc-A and Pc-B, respectively. In immobilized phases the attained reversible relative signal changes of Pc-A and Pc-B were 82 and 90%, respectively.     

Morphology,order, light transmittance,and water vapor permeability of aluminum‐coated polypropylene zeolite composite films

In this study, the polypropylene–zeolite composite films having 2–6 wt % natural zeolite were coated with a thin film of aluminum (Al) by magnetron sputtering, and the contribution of the Al coating on film properties was investigated. The samples were characterized by EDX, X‐ray diffraction, SEM, AFM, UV–visible spectroscopy, and water vapor permeation analyses. The surface of the films coated with a smooth Al film having 98–131 nm thickness. EDX revealed that Al percentage on the surface appeared to be as 8–10 wt % indicating contribution of polymer surface under Al film to analysis. XRD analysis showed that the grain size of Al at the surface was 22–29 nm. The surface roughness increased after Al‐coating process. The transmission of coated films was very low for both UV and visible regions of the light spectrum. Permeation analysis indicated that water vapor permeation was lower for Al‐coated material. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

DRYING OF AIR IN SILICA GEL PACKED COLUMNS

Silica gels that were made humidity indicating by impregnation of CoCl₂ were used for air drying in isothermal packed column. The effects of type of silica gel, packing height, particle size and air flow rate on breakthrough curves were studied. The breakthrough curves predicted by Rasmuson and Neretniek's analytical solution were in good agreement with experimental data.     

The effect of asymmetry on micromixing in curvilinear microchannels

The necessity of microscale mixing processes has been tremendously increasing in most of the microsize chemical and biochemical devices during recent years, particularly in the design of lab-on-a-chip and micrototal analysis systems. Different approaches were implemented in the available micromixers in the literature for improving the mixing performance. Due to the absence of any external source, mixing by utilizing passive mixing techniques is more economical. In curvilinear microchannels, which offer effective passive mixing, chaotic advection results in continuous radial perforation of inter-diffusion layer between the fluid streams due to the transverse secondary flows. In this study, the effects of Dean vortices and secondary flows were investigated in asymmetrical polydimethylsiloxane curvilinear rectangular microchannels, which were fabricated by one-step lithography process and had repeated S-shape patterns with a curvature of 280° along the channel. Moreover, the effect of asymmetry was assessed by comparing the mixing results with symmetrical microchannels. Mixing performance was analyzed by using NaOH and phenolphthalein solutions as mixing fluids, which entered from the channel inlets. According to the results, the significant effects of stretching and contracting motion of Dean vortices revealed themselves above a certain Dean number value, thereby making the asymmetrical microchannel outperform the symmetrical channel in the mixing performance. Below this threshold, the symmetrical microchannel was observed to be superior to the asymmetrical microchannel.     

Reflection mode scanning near-field optical microscopy analyses of integrated devices

Ultra-large-scale integrated devices have been investigated by a reflection mode scanning near-field optical microscope designed for semiconductor analyses. Although it could be found that imaging the reflectivity of metal structures buried underneath thin, optically transparent passivation layers is practicable, shading of the reflected light by the SNOM probe complicated the interpretability of the achieved results. This issue has been overcome by using the SNOM probe as both illumination source and detector, simultaneously. The application of focused ion beam milling to the probes has allowed the increase of the transmittivity of the probes to such an extent that coated fibres could be utilized and the interpretability of the results could be enhanced. Furthermore, the investigated structures are of great interest for an investigation of z-motion artefacts, as the presence of the polished passivation layers allows topographical influences to be distinguished from pure optical contrast.     

Deep learning based automatic grading of bi-colored apples using multispectral images

Multimedia Tools and Applications - Grading of apple fruits involves their inspection, assessment and sorting by quality. Machine vision has been the industry’s choice as it is fast, reliable...