Micro–Raman Spectroscopy of Diamonds from JaH 054 and Sahara 98505 Ureilites, Statistic Research

In this paper Raman spectra of diamonds from two different ureilites, JaH 054 and Sahara 98505, were measured. Obtained results for both ureilites showed the Raman shift ranged between 1321 cm -1 and 1336 cm -1 for JaH 054 and between 1329 cm -1 and 1336 cm -1 for Sahara 98505. FWHM parameter (full width at half maximum) varied also in wide range especially for Sahara 98505. Raman imaging was done for JaH 054 sample and diamonds of different Raman shifts (1321 cm-1, 1328 cm-1, 1330 cm-1) were found in few tens (im sized area of carbon vein. Raman peaks of ureilitic diamonds were compared with literature data of laboratory diamonds produced under high pressure, under low pressure with MW PACVD method and with other ureilites. Presented research showed that even in highly shocked ureilites Raman shift versus FWHM parameter plots are similar with CVD diamonds for ureilites. However, the origin of diamonds in ureilites is not explained based on the obtained results, close coexistence of different diamonds in investigated ureilites suggests that the mechanism of diamond creation in meteorites was very complex and could be multi-step process

The zoogeomorphology of case‐building caddisfly: Quantifying sediment use

Caddisfly (Trichoptera) larvae are an abundant and widespread aquatic insect group characterised by the construction of silk structures, including nets and cases. Case‐building caddisfly have the potential to modify the sorting and mobility of sand and fine gravel via; 1) case construction, resulting in altered sediment properties; 2) transporting sediment incorporated into cases over the river bed and; 3) changing the structure of river‐beds via burrowing. To investigate these mechanisms, it is necessary to understand the mass, size distribution and spatial variability of sediment use by case‐building caddisfly larvae.We quantified the mineral sediment used by individuals and communities of case‐building caddisfly in 27 samples, from three sites on a gravel‐bed stream. The mass and size distribution of sediment in individual cases varied between taxa (mass = 0.001 – 0.83 g, D50 = 0.17 – 4 mm). The mean mass of sediment used by the caddisfly community was 38 g m‐2 and varied locally. Sediment use was predominantly coarse sand (D50 = 1 mm). 64% of sediment use was attributable to Agapetus fuscipes (Glossosomatidae).Due to within‐species variability in case mass, the abundance of most taxa, including A. fuscipes, was only weakly associated with the mass of sediment used at the river scale. Whilst the caddisfly community used a small percentage of the total sediment available (average 2.99% of the 1‐1.4 mm size fraction), A. fuscipes used more fine sediment in their cases at sites where it was more available. Despite variability in local habitat, all sites supported diverse case‐building caddisfly communities utilising mineral sediment. Consequently, geomorphological effects of case‐building caddisfly are potentially widespread. The results provide novel insights into the specific grain sizes and quantities of fine sediment particles (g m‐2) used by caddisfly larvae, which represents an important step towards understanding their zoogeomorphic activities

SEM-EDX analysis of heavy metals in anal papillae of Hydropsyche angustipennis larvae (Trichoptera, Insecta) as a support for water quality assessment

Anal papillae of caddisflies are peripheral organs responsible for osmoregulation and detoxification. Investigation of morphological abnormalities in the anal papillae of Hydropsyche angustipennis enriched with using SEM-EDX analysis (scanning electron microscopy-energy dispersive X-ray analysis), was used to assess heavy metal pollution levels in urban streams receiving surface runoff. Heavy metal ions not previously detected in water and tissue samples by commonly used methods (e.g., AAS) were detected using SEM-EDX method. Analysis of heavy metal in the anal papillae revealed the presence of 11 elements (Fe>Mo>Mn≥Al>Cu>Pb≥Ni>Co≥As≥Ti≥V). Morphological irregularities were most frequently observed in larvae from the most contaminated streams. Most of the individuals collected from streams flowing through the city center and included in the sewage system had morphological abnormalities (~70%), contrary to the reference site (~10%). In pale, normal-shaped papillae the quantity of heavy metals was almost 10 times lower compared to darkened papillae. The present study confirms that SEM-EDX microscopy is an effective method as a support of standard heavy metal bioassays, especially if there is a necessity to detect trace elements in very small amounts of the tested material

AFM Investigation of Biological Nanostructures

Nanostructures created by living organisms, optimized through millions of years of evolution, can be a valuable inspiration for nanotechnology. We employ atomic force microscopy to examine such structures in materials created by common organisms - caddisfly and diatoms. Caddisfly larvae are well known for their ability to spin silk, which serves as an "adhesive tape" to glue various materials and collect food in aqueous environment. Atomic force microscopy imaging of caddisfly silk, performed for the first time by our team, has shown that its surface is patterned with 150 nm extensions - a feature related to its exceptional underwater sticking abilities. Results of force spectroscopy of protein structures found on the surface are also shown. A characteristic feature of diatoms is that they are encased within a unique silica cell wall called frustules, patterned with 200 nm pores, which allow cellular interaction with the environment. We perform atomic force microscopy imaging of frustules in living diatoms as well as adhesion measurements inside pores

AFM Investigation of Biological Nanostructures

Nanostructures created by living organisms, optimized through millions of years of evolution, can be a valuable inspiration for nanotechnology. We employ atomic force microscopy to examine such structures in materials created by common organisms - caddisfly and diatoms. Caddisfly larvae are well known for their ability to spin silk, which serves as an "adhesive tape" to glue various materials and collect food in aqueous environment. Atomic force microscopy imaging of caddisfly silk, performed for the first time by our team, has shown that its surface is patterned with 150 nm extensions - a feature related to its exceptional underwater sticking abilities. Results of force spectroscopy of protein structures found on the surface are also shown. A characteristic feature of diatoms is that they are encased within a unique silica cell wall called frustules, patterned with 200 nm pores, which allow cellular interaction with the environment. We perform atomic force microscopy imaging of frustules in living diatoms as well as adhesion measurements inside pores

Transparent and air stable organic field effect transistors with ordered layers of dibenzo[d,d]thieno[3,2-b;4,5-b′]dithiophene obtained from solution

International audienceIn a search for solution processable and stable p-type semiconductors an analogue of pentacene namely dibenzo[d,d]thieno[3,2-b;4,5-b′]dithiophene (DBTDT) - was tested as an active layer in organic field effect transistors (OFETs). It was found that thin, continuous and transparent films of DBTDT can be obtained with the help of solution based zone-casting technique. This deposition technique allows one to produce highly oriented crystalline layers of DBTDT showing similar molecular arrangement as that of a single crystal. The zone-cast layers of DBTDT were successfully applied in a fabrication process of OFETs with Parylene C® used as the gate dielectric. The best parameters are exhibited by the devices with the bottom-gate, top contact configuration: charge carrier mobility of ca 0.02 cm2/Vs and threshold voltage of ca −50 V and performance of these OFETs remains unchanged after 1 months storage in air