In order to exploit the peculiar characteristics of synchrotron radiation for X-ray mammography purposes, monochromatic X-ray beams of selected energies from 16 keV to 22 keV have been used for the first time ever to obtain mammograms of surgically removed breast specimens containing cancer nodules. The apparatus devised particularly in view of a possible clinical applications, allowed large breast specimens fixed in space to be exposed to a vertical scanning X-ray beam. The mammograms obtained with synchrotron radiation, compared with those made using a traditional mammographic unit had higher contrast and better resolution demonstrating, in all the cases studied, a high capability to display a large number of structures inside the neoplastic lesions. Thermoluminescent dosimeters were used to determine the doses. The average mean glandular doses, at 17 keV and 18 keV, were 1.56 mGy and 0.84 mGy, respectively, comparable with the value of 1.41 mGy delivered with the conventional grid apparatus.
Besides the crystal preparation, the first and crucial step in the process of protein structure determination is proper processing of the collected diffraction images, as they provide the experimental observations used throughout the entire process of structure solution and refinement. In the last two decades several computer programs have been developed. Among the most used and popular are: HKL2000, MOSFLM, d*TREK and XDS package. To find out the advantages and disadvantages of the data processing programs, several very different data sets, including diffraction data from DNA/RNA and protein crystals were tested. It has been found that all the major programs for processing and analysis of diffraction data give excellent and comparable results with good quality, medium resolution data sets, but their treatment of very high resolution or imperfect data differs in terms of indexing, spot integration, scaling and the treatment of errors. If the diffraction data are of good quality and the problem is relatively straightforward, the automated approach to data processing may be most appropriate. On the other hand, if one is trying to squeeze out as much information from the experimental data as possible, then only expert manual processing can be successful, regardless of the data quality.
X-ray crystallography is the natural choice for macromolecular structure determination by virtue of its accuracy, speed, and potential for further speed gains, while synchrotron radiation is indispensable because of its intensity and tuneability. Good X-ray crystallographic diffraction patterns are essential and frequently this is achievable through using the few large synchrotrons located worldwide. Beamline time on these facilities have long queues, and increasing the efficiency of utilization of these facilities will help in expediting the structure determination process. Automation and remote data collection are therefore essential steps in ensuring that macromolecular structure determination becomes a very high throughput process.
The installation of the wavelength shifter at the BESSY I storage ring in Berlin makes it possible to apply the synchrotron radiation for white beam investigations of organic multilayers. Considering the energy characteristic of the synchroton radiation source and the absorbance of the beryllium window the synchrotron radiation can be used outside the UHV system for X-ray reflectometry and X-ray diffuse scattering between about 3 keV and 25 keV. Between 3 and 10 keV the synchrotron radiation intensity is high enough to realize the grazing incidence diffraction mode in order to get in-plane information. The capability of the methods is demonstrated at the example of a Pb-stearate multilayer covered by a thin polyelectrolytic polymer layer.
The described synchrotron radiation beam line, based on a double mono-chromator with different incidence angles, has been devised to ally in a short length the working possibilities of both vacuum ultraviolet and soft X-ray monochromators as well as to preserve the degree of circular polarization of the radiation emitted by the source. The design philosophy and the predicted performances of the diffraction and the focusing systems are described and the heat load on the beam line optical elements is discussed. Some practical details concerning the beam line, now under construction, are presented.
New powerful sources and advanced analytical techniques have been considered in the last decade to face up the continuously increasing scientific demands, in particular, in materials science. As an example, nano- science and nanotechnology researches are characterized by ultimate spatial resolution, fast and ultrafast time-resolved analysis, but the complexity of the investigated phenomena requires new analytical capabilities and new experimental techniques were introduced in the research arena. The availability all over the world of brilliant synchrotron radiation sources offers incredible opportunities. Many challenging experiments were made possible by these sources and understanding of many complex dynamical problems was obtained. Nevertheless, a strong demand of new analytical approaches, mainly based on concurrent and possibly simultaneous time-resolved experimental techniques, is emerging. Pioneering time resolved experiments combining X-ray and infrared radiation with a conventional source were performed more than a decade ago. Nowadays, many beamlines at third generation synchrotron radiation facilities are equipped with conventional sources to allow complementary techniques and the strategy of a concurrent analysis is mandatory in the investigation of many phenomena in frontier multidisciplinary researches. Moreover, new opportunities will be available by means of concurrent spectroscopic experiments investigating complex phenomena on a short timescale, from the sub-second to the microsecond time domain. We will present and discuss researches where the combination of IR and X-ray simultaneous experiments may return unique information on complex dynamical processes and phase transitions occurring in materials science. Finally, we will briefly describe the conceptual layout of a synchrotron radiation beamline to perform concurrent IR and X-ray experiments.
Bivalves, oysters, mussels, and clams are important constituents of riverine and estuarine ecosystems. Their shells and soft tissues provide information on the environments in which they live. Since they are filter feeders, they also are factors in improving water quality through removal of particulate matter from the water column. Finally, they are a valuable food source that has substantial economic value. Hence, characterization of shells and soft tissues is useful for improved understanding of these factors. Here, we used X-ray microprobes and computed microtomography facilities at the Brookhaven National Synchrotron Light Source to investigate elemental distributions in bivalves taken from locations around New York, Washington, DC, and New Orleans, LA. The results form the initial basis for compilation of a database of relevant parameters that can serve for tracking environmental changes and for assessing toxicity of particular metals. The work was enabled by active collaboration with students from the several regions, community groups, and research scientists. The collaboration was facilitated through use of web conferencing between Brookhaven National Laboratory and the varied locations.
A beamline for macromolecular crystallography is under construction at the Swedish synchrotron light source MAX-lab at Lund University in a collaborative effort between Denmark and Sweden. Of the 7 mrad horizontal wiggler fan emitted from the new superconducting multipole wiggler, the central 2 mrad will be used and split in three parts. The central 1 mrad will be used for a tunable station optimised for multi-wavelength anomalous diffraction experiments and on each side of the central fan there will be two fixed wavelength stations using different energies of the same part of the beam. These in total five stations can be used simultaneously and independently for collecting diffraction data.
Newly constructed 4th generation sources of intense synchrotron radiation in ultrafast pulses of only 10-50 fs and wavelengths up to X-rays, the free electron lasers, are expected to revolutionize development of biological science. To take full advantage of unique properties of the sources, new imaging techniques of molecular and microscopic biological objects are developed. Present article provides a short review of a stormy development of bioimaging with incoming soon 4th generation synchrotron radiation X-ray sources. Some implications for the future of new sources and techniques are discussed as well.
The advent of free electron lasers opens up new opportunities to probe the dynamics of ultrafast processes and the structure of matter with unprecedented spatial and temporal resolution. New methods inaccessible with other known types of radiation sources can be developed, resulting in a breakthrough in deep understanding the fundamentals of life as well as in numerous medical and biological applications. In the present work the properties of free electron laser radiation that make the sources excellent for probing biological matter at an arbitrary wavelength, in a wide range of intensities and pulse durations are briefly discussed. A number of biophysical and biomedical applications of the new sources, currently considered among the most promising in the field, are presented.
Fourier Transform Infrared (FTIR) spectroscopy is a fundamental technique capable to characterize proteins and to investigate their conformation and dynamics in real physiological environments. Actually, a FTIR spectrum is characterized by many features, which may be correlated to the different components of the protein structure. In the last decade many relevant results have been achieved with this technique in terms of chemical imaging of proteins at subcellular level and in the investigation of cooperative phenomena. This contribution presents a few examples that illustrate the capability of the FTIR spectroscopy to investigate both protein structure and function and the opportunities offered by IR synchrotron radiation sources. Indeed the high source brilliance of these sources enables FTIR micro-spectroscopy to be performed with spatial and time resolution not available with standard sources. Moreover, the combination of synchrotron radiation and new two-dimensional detectors open new opportunities to investigate in the IR energy domain different protein processes in real time and with proteins in their native environments.
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