Phage display antibody-based proteomic device using resonance-enhanced detection

The combination of phage display antibody arrays with a novel nanotransducer technique based on resonant nanoparticles in a nanosandwiched film enables the sensitive parallel screening of proteins. Using the resonance of nanoparticles with their induced mirror dipoles in a thin-film structure, limitations of fluorophores, such as unspecific background and nonvisibility to the eye, can be overcome, thereby leading to an optical signal significantly more sensitive than that of standard colloid techniques. The signal can be both directly observed as a color change of a microdot at the sensor surface and tuned throughout the visible range of the spectrum. Here we report the application of an optical chip using scFv-antibody-antigen interactions. Artificial scFv-antibodies against a variety of proteins, including yeast enzymes and bovine serum albumin (as a standard), were constructed via Phage Display. These scFv-antibodies were then coated onto metal nanoclusters and bound to their antigens that were arrayed as nanodroplets at the resonance layer of the chip. ScFv-Antibody-antigen interaction resulted in a visible array of microdots. Using resonance-enhanced absorption, the absorption signal of the spots was amplified by one to two orders of magnitude (compared to colloid-based techniques). For quantitative analysis, either an 8-micron scanner or a CCD camera (resolution 4 microns) was employed to gain direct-reflection spectra rather than unspecific scatter data (prone to dust and unspecific interaction). Our results demonstrate that this device enables high-throughput proteomics to overcome some limitations of fluorescence, enzyme labels, and colloid techniques.     

System for personal dosimetry in interventional radiology

The progress made in radiological image processing and transmission is being widely applied in new branches of medicine. The increasing use of interventional radiology in research and clinical practice means that new groups of workers are being exposed to radiation and need to be covered by a system of radiation protection. Interventional radiology requires the operator and assisting personnel to remain close to the patient; typically these procedures require placement of the hands within the radiation field. A system of hand dose monitoring was introduced in Poland in 2000. This system uses ring badges with TL dosemeters. The measurements conducted so far characteristically show an asymmetric right-sided distribution of monthly doses. As expected, operators and their assistants are the most exposed groups of medical personnel. Average hand doses may be very dependent on the type of procedure, personal skills and quality of equipment. The hand doses of these personnel are significant from a radiological protection point of view.     

Form assessment of hollow cylindrical specimens

Grazing-incidence interferometry that makes use of diffractive axicons for the measurement of cylindrical mantle surfaces has already been reported. However, measurement of concave rod structures poses a severe problem because these structures are subject to spurious fringes caused by parasitic diffraction orders of the diffractive axicons. By breaking the symmetry of the interferometric setup it is possible to obtain unique interferograms of the inner mantle surfaces of hollow cylinders as cages for roller bearings or other workpieces produced on lathe machines that have a suitable surface finish. Special design issues for the computer-generated holograms and the interferometric setup are discussed, and test examples are given.     

Chromium-scandium multilayer mirrors for the nitrogen K(alpha) line in the water window region

Chromium-scandium (Cr-Sc) is a promising material combination for multilayer mirrors in the water window region. A possible x-ray source for laboratory use in this wavelength range is the nitrogen K(alpha) line at 3.16 nm. High reflectivities at this wavelength can be achieved with Cr-Sc multilayer mirrors if the interfaces between adjacent layers are smooth. The growth parameters of the magnetron sputtering process for these materials have been optimized. It is shown that the reflectivity of such mirrors can be considerably improved by the application of a proper bias voltage during film growth. The high quality of the multilayer films is demonstrated with copper K(alpha) x-ray reflection and transmission electron microscopy. The reflective properties of the multilayers close to the nitrogen K(alpha) line were measured with synchrotron radiation for different angles of incidence. Reflectivities between R = 5.9% for near-normal incidence (theta = 1.5 degrees) and R = 29.6% for theta = 59.9 degrees were measured.     

Validating visual clusters in large datasets: fixed point clusters of spectral features

Finding clusters in large datasets is a difficult task. Almost all computationally feasible methods are related to k-means and need a clear partition structure of the data, while most such datasets contain masking outliers and other deviations from the usual models of partitioning cluster analysis. It is possible to look for clusters informally using graphic tools like the grand tour, but the meaning and the validity of such patterns is unclear. In this paper, a three-step-approach is suggested: In the first step, data visualization methods like the grand tour are used to find cluster candidate subsets of the data. In the second step, reproducible clusters are generated from them by means of fixed point clustering, a method to find a single cluster at a time based on the Mahalanobis distance. In the third step, the validity of the clusters is assessed by the use of classification plots. The approach is applied to an astronomical dataset of spectra from the Hamburg/ESO survey.     

Gemeinsamer Einfluß yon Mangan- und Magnesiumoxid auf die Schlackengleichgewichte im System Fe–CaO–FeOn–SiO2 bei 1600 °C

Ebene Darstellung eines Vielstoffsystems durch mehrfache Parallelprojektion. Schlackengleichgewichte im System Fe–CaO–FeO_n–SiO₂–MnO_n–MgO bei 1600 °C. Mikroskopische Untersuchung der Schlackenphase. Theoretische Entwicklung von Sättigungslinien für ausgewählte konstante Gehalte von Einzelstoffen. Erörterung der Ergebnisse im Hinblick auf ?LD?- und Siemens-Martin-Schlacken.     

Optical forces for noninvasive cellular analysis

A novel, noninvasive measurement technique for quantitative cellular analysis is presented that utilizes the forces generated by an optical beam to evaluate the physical properties of live cells in suspension. In this analysis, a focused, near-infrared laser line with a high cross-sectional intensity gradient is rapidly scanned across a field of cells, and the interaction of those cells with the beam is monitored. The response of each cell to the laser depends on its size, structure, morphology, composition, and surface membrane properties; therefore, with this technique, cell populations of different type, treatment, or biological state can be compared. To demonstrate the utility of this cell analysis platform, we evaluated the early stages of apoptosis induced in the U937 cancer cell line by the drug camptothecin and compared the results with established reference assays. Measurements on our platform show detection of cellular changes earlier than either of the fluorescence-based Annexin V or caspase assays. Because no labeling or additional cell processing is required and because accurate assays can be performed with a small number of cells, this measurement technique may find suitable applications in cell research, medical diagnostics, and drug discovery.     

Ronan Point Apartment Tower Collapse and its Effect on Building Codes

In the early morning hours of May 16, 1968, the occupant of apartment 90 on the 18th floor of the 22-story Ronan Point apartment tower, in London, lit a match to brew her morning cup of tea. The resulting gas explosion initiated a partial collapse of the structure that killed four people and injured 17 (one of whom subsequently died). On investigation, the apartment tower was found to be deeply flawed in both design and construction. The existing building codes were found to be inadequate for ensuring the safety and integrity of high-rise precast concrete apartment buildings. The Larsen–Nielson building system, intended for buildings with only six stories, had been extended past the point of safety. The tower consisted of precast panels joined together without a structural frame. The connections relied, in large part, on friction. The apartment tower lacked alternate load paths to redistribute forces in the event of a partial collapse. When the structure was dismantled, investigators found appallingly poor workmanship at the critical connections between the panels. Subsequently, building codes in many countries have adopted structural integrity or “robustness” provisions that may be directly traced to the Ronan Point collapse.     

Ideal Is Typical.

A well-established finding in research on concepts and categories is that some members are rated as better or more typical examples than others. It is generally thought that typicality reflects centrality, that is, that typical examples are those that are similar to many other members of the category. This interpretation of typicality is based on studies in which participants had little knowledge about the relevant categories. In the present study, experienced fishermen were asked to give goodness-of-example ratings to familiar freshwater fish. These fishermen were of two cultural groups with somewhat different goals and ideals. Typicality was well predicted by fishes' desirability and poorly predicted by their centrality. Further, the two cultural groups differed in their typicality ratings in ways that corresponded to their different goals and ideals. For knowledgeable reasoners typicality in natural taxonomic categories appears based on ideals rather than on centrality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)