How to Make Drugs Orally Active: A Substrate Template for Peptide Transporter PepT1

By building key structural features into hydrophilic drugs, they can be recognized by the PepT1 transporter system of the small intestine and rendered orally active. The model shown provides, for the first time, a 3D template for all known substrates of PepT1.     

ArtTAX - a new mobile spectrometer for energy-dispersive micro X-ray fluorescence spectrometry on art and archaeological objects

A newly developed spectrometer for energy-dispersive micro X-ray fluorescence spectrometry has been designed for the demands of archaeometry. ArtTAX combines the advantages of non-destructive and sensitive multi-elemental analysis at sub-mm resolution with the possibility of working outside the laboratory. The spectrometer consists of an air-cooled, low-power molybdenum tube, new generation polycapillary X-ray optics, a silicon drift detector without the need for liquid-nitrogen cooling, a CCD camera, and three light diodes for sample positioning. The motor-driven measurement head is fixed on a x,y,z-flexible tripod support which can be assembled and dismantled within minutes. The spot size of the primary X-ray beam was determined to be 94 microm for the Cu(Kalpha) energy, the detection limits are in a range of a few tens of microg g(-1) for the medium energy-range in glass. Additional open helium purging in the excitation and detection paths enables the determination of elements down to sodium, thus avoiding vacuum conditions or a size-limiting sample chamber. A selection of qualitative and quantitative results on pigment, metal, glass, and enamel analyses are presented to show the potential of ArtTAX in the field of art and archaeology.     

Simultaneous monitoring of pH, CO2 and O2 using an optical imaging fiber

The interdependence of pH, CO₂ and O₂ during chemical and biochemical processes has driven the need to monitor them simultaneously, continuously and in situ, in order to exert better control over such reactions. We present the fabrication and performance of a multi-analyte imaging fiber sensor that allows pH, CO₂ and O₂ to be monitored simultaneously with rapid response. Sensing elements are fabricated by covalently immobilizing fluorescent indicators within polymer matrices via photopolymerization, resulting in the formation of distinct regions of analyte-sensitive polymer at the fiber's distal end. The multianalyte sensor's working range is 0%–100% for O₂ and 0%–10% for CO₂ in the pH range 5.5–7.5. The sensor was used to monitor the pH, CO₂ and O₂ changes during a beer fermentation.     

Fluorescent optical sensors

Optical sensors are prepared by immobilizing an indicating layer on the distal end of a fiber optic cable. Dyes, enzymes, and antibodies can all be incorporated into the layer using a variety of immobilization techniques. Much of the present work is devoted to developing novel indicating schemes by combining appropriate recognition schemes into polymeric matrices.     

Two-dimensional angular optical scattering patterns of microdroplets in the mid infrared with strong and weak absorption

Two-dimensional angular optical scattering (TAOS) patterns of droplets composed of a mixture of H2O and D2O are detected in the mid infrared. First, a lens is used in the Abbé sine condition to collect a small solid angle of light, where the scattering pattern matches well numerical simulations based on Mie theory. Next, TAOS patterns from droplets spanning a large (approximately 27pi sr) solid angle are captured simultaneously at two wavelengths. The effects of absorption are evident in the patterns and are discernible without the need for curve matching by Mie theory.     

A new concept for the quasi non-destructive microsampling of historical glasses

A mobile and easily practicable microsampling technique for historical glasses and its application is presented. About 100 μg of material is scraped off the object with a fine grinding file. The analysis of main, minor and trace elements in the digested sample is performed by IC, GFAAS and FIA with photometric detection. The procedure has been verified by measurements of standard glasses. Investigations of baroque ruby glasses showed the suitability of the microsampling technique for archaeometrical application. Received: 6 January 1997 / Revised: 17 March 1997 / Accepted: 25 March 1997     

A new concept for the quasi non-destructive microsampling of historical glasses

A mobile and easily practicable microsampling technique for historical glasses and its application is presented. About 100 μg of material is scraped off the object with a fine grinding file. The analysis of main, minor and trace elements in the digested sample is performed by IC, GFAAS and FIA with photometric detection. The procedure has been verified by measurements of standard glasses. Investigations of baroque ruby glasses showed the suitability of the microsampling technique for archaeometrical application. Received: 6 January 1997 / Revised: 17 March 1997 / Accepted: 25 March 1997     

Synthesis of nonconjugated dendrons with a redox gradient

Macromolecules with built-in redox gradients are of much interest due to their potential in a variety of optoelectronic and energy-harvesting applications. In this paper, the design and synthesis of nonconjugated dendrons with redox gradients to guide the charge flow from the core to the periphery is described. The dendrons reported here are based on benzyl ether connectivities. The repeat units of the dendrons are based on triarylamines, and the periphery units of the dendrons are based on N,N,N',N'-tetraarylbenzidine units. The presence of a redox gradient after incorporation of these charge-transporting units into the dendrons is supported by cyclic voltammetric studies.