Chemical modification of Topaz surfaces

In chemisorption, one is typically faced with the problem that the two-dimensional structure of the organic layer does not match the structure of the inorganic substrate. This work describes the first steps toward an induced epitaxial correlation of organic compounds on an inorganic surface. The idea of this work was to use a single crystal with a two-dimensional surface structure, Topaz (001), that matches an alkyl chain lattice better than existing substrates. X-ray reflectivity and FTIR experiments prove the surface modification of the Topaz, which is probably an etherification of the reactive OH-groups on the Topaz (001) surface.     

Ultrasonic cavitation at solid surfaces

In spite of the great potential of applying high-intensity ultrasound, which enables high-temperature and high-pressure chemistry with a reactor near room temperature and ambient pressure, sonochemistry at solid surfaces is at a weak stage of understanding with regards to the development of new materials and composite nanostructures. The science towards a quantitative understanding is only now emerging. On the other hand, in many applications an ultrasonic bath is used without thinking of the mechanism. Often surfaces are exposed to ultrasound for cleaning. Since ultrasonic treatment is not an exotic process and applicable even on large scale in industrial manufacturing, controlling the process may lead to new applications making use of the specially designed surface. This review is intended to summarize recent progress in this field and to point out most promising directions of ultrasound application for the development of new materials with functional surfaces.     

Controlled effect of ultrasonic cavitation on hydrophobic/hydrophilic surfaces

Controlling cavitation at the solid surface is of increasing interest, as it plays a major role in many physical and chemical processes related to the modification of solid surfaces and formation of multicomponent nanoparticles. Here, we show a selective control of ultrasonic cavitation on metal surfaces with different hydrophobicity. By applying a microcontact printing technique we successfully formed hydrophobic/hydrophilic alternating well-defined microstructures on aluminium surfaces. Fabrication of patterned surfaces provides the unique opportunity to verify a model of heterogeneous nucleation of cavitation bubbles near the solid/water interface by varying the wettability of the surface, temperature and ultrasonic power. At the initial stage of sonication (up to 30 min), microjets and shock waves resulting from the collapsing bubbles preferably impact the hydrophobic surface, whereas the hydrophilic areas of the patterned Al remain unchanged. Longer sonication periods affect both surfaces. These findings confirm the expectation that higher contact angle causes a lower energy barrier, thus cavitation dominates at the hydrophobic surfaces. Experimental results are in good agreement with expectations from nucleation theory. This paper illustrates a new approach to ultrasound induced modification of solid surfaces resulting in the formation of foam-structured metal surfaces.     

Polymer Brush Gradients by Adjusting the Functional Density Through Temperature Gradient

The group of silanes is one of the most abundant classes of molecules used for surface modification. In most studies, silanization is made from the vapor phase or solution. Here, an easy, robust, and fast way not only to modify, but also to map, control, and predict the wetting profiles on silicon surfaces after silanization and the final characteristics of a brush layer polymerized from this silane template profile are presented. The initiator molecule, 2‐bromo‐2‐methyl‐N‐3‐(triethoxysilyl) propyl propanamide (BTPAm), is spin‐casted on a silicon substrate and a thermal gradient is applied using a combinatorial approach for studying the influence of temperature on the spin‐casted silanes. Subsequently, polyacrylamide (PAAm) brushes are grown from the initiating end group of the BTPAm molecules through atom transfer radical polymerization (ATRP). Simulations of the heat distribution inside the silicon wafer allow both confirming the mapping of surface properties and designing desired profiles by predicting thermal distributions. An analytical expression for quantification is also provided. Thus, the wetting properties, surface roughness, and morphology of the brush layer after polymerization are mapped and correlated with the initial BTPAm gradient profile. The studies presented are envisioned to be of interest for designing surface profiles with different wetting properties, facilitating polymer brush growth, and to be used as predictive tools.     

Interlaboratory diagnostic accuracy of a Salmonella specific PCR-based method

A collaborative study involving four European laboratories was conducted to investigate the diagnostic accuracy of a Salmonella specific PCR-based method, which was evaluated within the European FOOD-PCR project (http://www.pcr.dk). Each laboratory analysed by the PCR a set of independent obtained presumably naturally contaminated samples and compared the results with the microbiological culture method. The PCR-based method comprised a preenrichment step in buffered peptone water followed by a thermal cell lysis using a closed tube resin-based method. Artificially contaminated minced beef and whole broiler carcass-rinse resulted in a detection limit of less than 5 cells per 25 g meat or 100 ml broiler rinse. A total of 435 samples from four countries, including pig carcass swabs (n = 285), whole broiler carcass-rinse (n = 25), various raw meat (n = 33), and environmental samples (n = 92) were investigated. The interlaboratory diagnostic accuracy, i.e. diagnostic specificity and sensitivity, was shown to be 97.5%. The co-amplification of an internal amplification control indicated possible inhibitory substances derived from the sample. This work can contribute to the quality assurance of PCR-based diagnostic methods and is currently proposed as international standard document.     

Neuroticism and extraversion in Turner's Syndrome.

Administered the Maudsley Personality Inventory to 5 groups of female Ss: (a) 13 Turner Syndrome Ss (mean age 19 yrs 2 mo) with karyotype 45X, (b) 18 Turner Syndrome (TS) Ss (mean age 26 yrs 11 mo) with other types of sex chromosomal abnormalities, (c) 16 sisters of Ss (mean age 24 yrs 2 mo), (d) 9 Ss with growth retardation and primary amenorrhea (mean age 22 yrs 4 mo), and (e) 19 nurses (mean age 22 yrs 8 mo). The results are compared to English and American normative values. The total group of TS Ss obtained a low Neuroticism (N) score compared to the control groups. When the total group was divided on the basis of their karyotypes, the low N score could be referred solely to Ss with karyotype 45X, who scored significantly lower than any other group tested so far with the MPI. TS Ss with chromosomal abnormalities other than 45X scored within normal limits. No variables other than karyotype 45X were related to an extremely low N score. It is concluded that exceptional emotional stability, as reflected in a very low N score on the MPI, is concomitant with the total absence of one sex chromosome, which is probably due to a developmental abnormality of the CNS. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)