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1

Bioimaging with 4th Generation X-Ray Sources

100%

Pełka J.

Acta Physica Polonica A

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2009

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vol. 115

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issue 2

572-575

EN

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.

2

Synchrotron Radiation in Biology and Medicine

100%

Pełka J.

Acta Physica Polonica A

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2008

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vol. 114

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issue 2

309-329

EN

This work is focused on a present status of synchrotron radiation X-ray applications in medicine and biology to imaging, diagnostics, and radiotherapy. Properties of X-ray beams generated by synchrotron sources are compared with radiation produced by classical laboratory X-ray tubes. A list of operating and planned synchrotron facilities applicable to biomedical purposes is given, together with their basic characteristics. A concise overview of typical X-ray synchrotron techniques in biology and medicine is carried out with discussion of their specific properties and examples of typical results.

3

X-Ray Standing Wave Technique as a Tool in the Study of the Imperfect Crystals

64%

Pełka J., Auleytner J.

Acta Physica Polonica A

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1992

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vol. 82

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issue 1

163-171

EN

The application of the X-ray standing wave (XSW) technique in the case of imperfect crystals meets serious theoretical and interpretational problems. However, well-known advantages of the XSW technique make it especially interesting to the study of the ordering of impurities and of various processes leading to changes in this ordering in various likes of imperfect crystals. In this work we try to answer the question how imperfection of a crystal may influence the changes in fluorescence yield during the XSW measurement. Two likes of imperfect crystals are studied: Si(111) implanted with high energetic Bi^{+} ions, and Zn_{1-x}Co_{x}Se single crystal with natural (111) face. The discussion of obtained results shows that general features of the X-ray standing wave field are conserved despite the considerable imperfections of the crystals. The results seem to support the applicability of the XSW technique to the study of imperfect materials, although some further theoretical effort would be required.

4

Metrological Applications of X-ray Waveguide Thin Film Structures in X-ray Reflectometry and Diffraction

64%

Pełka J., Lagomarsino S.

Acta Physica Polonica A

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2002

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vol. 102

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issue 2

233-238

EN

The effect of resonance, observed in X-ray waveguide layered structures in a characteristic way influences the scattering properties of the films. It is well known that in the resonant region the reflectivity shows a series of minima, usually very deep and extremely narrow. The positions and depths of the minima depend only on X-ray waveguide structural properties, on the X-ray wavelength and on the incident beam divergence. In the present work we propose and discuss the application of the X-ray waveguide and quasi X-ray waveguide film structures as tools to experimental evaluation of some quantities related to X-ray reflectometric or diffractometric measurements, like the beam divergence, wavelength, or angular distance. Examples of application of the X-ray waveguide as an excellent tool to estimate the effective beam divergence are shown. Properties of the X-ray waveguide elements as a handy wavelength or angular calibration standard are also mentioned.

5

Effective Velocity of Soliton in the Presence of a Periodic Background

64%

Pełka J., Zagrodziński J.

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EN

The effective soliton velocity in the presence of a periodic background differs from that when a soliton propagates alone. Using approximate relations for the Riemann-theta functions, the effective soliton velocity is derived and discussed. General relations are illustrated by examples of Korteweg de Vries and sine-Gordon equations because of the application in the Josephson junction theory.

6

Applications of Free Electron Lasers in Biology and Medicine

51%

Pełka J., Tybor K., Nietubyć R., Wrochna G.

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issue 2

427-432

EN

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.

7

Old Studies with New Authors: A Discovery Ending with Retraction

51%

Paszkowicz W., Pełka J., Krupka J., Abramowicz A.

Acta Physica Polonica A

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2011

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vol. 119

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issue 6

901-903

8

Lattice Parameters of Aluminium Nitride in the Range 10-291 K

45%

Paszkowicz W., Knapp M., Podsiadło S., Kamler G., Pełka J.

Acta Physica Polonica A

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2002

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vol. 101

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issue 5

781-785

EN

Lattice parameters for aluminium nitride were determined using X-ray powder diffraction at a synchrotron radiation source (beamline B2, Hasylab/DESY, Hamburg) in the temperature range from 10 K to 291 K. The measurements were carried out using the Debye-Scherrer geometry. The relative change of both, a and c, on rising the temperature in the studied range (10-291 K) is about 0.03%. The results are compared with earlier laboratory data and theoretical predictions.

9

Oscillations in Reflectivity of Samples with X-ray Waveguide Layers

45%

Pełka J., Lagomarsino S., Di Fonzo S., Jark W., Domagała J.

Acta Physica Polonica A

|

1996

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vol. 89

|

issue 3

323-328

EN

The glancing-angle reflectivity profiles in samples containing an X-ray waveguide layer are studied. Oscillations observed at angles within the region of resonance and above, are interpreted by angle dependent interference of the monochromatic X-ray beam in thin layer. The discussion is extended to the structures composed of more than one layer. Experimental reflectivity spectra recorded with Cu K_{α} radiation are compared with the theoretical calculations. It leads to the model of oscillations in reflectivity consistent both for the resonant and non-resonant regions, and clarifies interpretation of oscillations in the region above the resonances. A brief discussion of potential applications of the reflectivity spectra to the studies of structure of thin layers is done.

10

X-Ray and Electron-Optical Characterization of ZnTe/CdTe and ZnTe/GaAs Epitaxial Layers Obtained by the MBE Method

45%

Auleytner J., Dziuba Z., Górecka J., Pełka J., Regiński K.

Acta Physica Polonica A

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1994

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vol. 86

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issue 4

567-574

EN

X-ray diffraction topography (Bragg diffraction) and X-ray rocking curve measurements were used to study the perfection and structural properties of ZnTe epitaxial layers on the CdTe and GaAs substrates. ZnTe epitaxial layers on CdTe were grown by MBE method by using a machine made in the Institute of Physics of the Polish Academy of Sciences. The ZnTe layers on GaAs were produced on the other, factory-made MBE system. The comparison between the X-ray topographical images of the substrate and epitaxial layer shows that imperfections on the substrate surface cause imperfections in the epitaxial layer. The results of double-crystal diffractometry measurements show that the perfection of the layer on the GaAs substrate is higher than that on the CdTe. The presence of microtwining in the ZnTe layer on the CdTe substrate was confirmed by RHEED measurements. The X-ray standing wave fluorescent spectra were also measured for the samples.

11

Study of Si-Implanted and Thermally Annealed Layers of Silicon by Using X-ray Grazing Incidence Methods

39%

Klinger D., Lefeld-Sosnowska M., Pełka J., Paszkowicz W., Gierłowski P., Pankowski P.

Acta Physica Polonica A

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2002

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vol. 101

|

issue 5

795-801

EN

This paper reports on the study of structural modifications induced by the implantation process and by the subsequent thermal annealing in near-surface layers of Si single crystals implanted with Si^{2+} ions of energy 140 keV and doses from 1×10^{15} to 1× 10^{16} ions/cm^2. The grazing incidence X-ray diffraction and X-ray reflectivity measurements were applied to determine the thickness and structural composition of the damaged layers. The fitted electron density profiles indicated an existence of an interfacial layer with density higher than the density of Si matrix or near-surface oxide layer. Formation of polycrystalline phases of silicon and silicon oxides is discussed in dependence on the conditions of annealing treatment and implantation dose.

12

X-ray Characterization of Films Formed by Pulsed Laser Deposition on Cold Substrates from YBaCuO Targets

39%

Pełka J., Paszkowicz W., Gierłowski P., Lewandowski S., Zieliński M., Barbanera S., Knapp M.

Acta Physica Polonica A

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2002

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vol. 101

|

issue 5

787-794

EN

Grazing-incidence X-ray diffraction supplemented with atomic force microscopy and secondary ion mass spectroscopy were applied to the characterization of films deposited by laser ablation on cold substrates from YBaCuO targets and subsequently irradiated with additional laser pulses of lower energy density. Evolution of X-ray diffraction pattern was observed as a function of irradiation dose. For the as-deposited films the pattern was typical of the amorphized solids. For the films irradiated with doses higher than the threshold, the pattern was enriched with the diffraction peaks, whose general features, like peak positions, widths and relative intensities were almost independent of the dose. The size of the crystallites was deduced from the peak widths to be not smaller than 12-16 nm. Comparison of the pattern with patterns of known phases indicates that, apart of the amorphous component, a structure with an admixture of some new metastable or high temperature phase(s) is formed during the process of pulsed laser annealing. The atomic force microscopy observations revealed that the surface roughness shows a pronounced minimum at low irradiation doses. The secondary ion mass spectroscopy investigation confirms that the strongest chemical changes (increase in concentration of yttrium and copper) due to irradiation with higher doses are observed in the near-surface film material.

13

X-Ray and Electron-Optical Characterization of ZnSe(Co) Crystal with Natural Face

39%

Auleytner J., Domagała J., Gołacki Z., Pawłowska M., Pełka J., Regiński K.

Acta Physica Polonica A

|

1993

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vol. 83

|

issue 6

759-768

EN

Using complementary X-ray and electron-optical methods, a ZnSe(Co) crystal with natural face was investigated. X-ray diffraction methods such as double-crystal X-ray reflection topography, double-crystal diffractometry for rocking curve measurements, precise lattice constant measurements by the Bond technique were used for crystal structure characterization and X-ray fluorescence method for studies of chemical composition along the crystal. The scanning electron microscopic image of the crystal surface and reflection diffraction of the high-energy electrons enriched the crystal structure characterization. It was shown that X-ray characterization and reflection high-energy electron diffraction can be regarded as very important complementary tools for non-destructive investigation of the ZnSe(Co) crystal surface layers.

14

Structure and Magnetism of MBE-Grown Co/Cu Multilayers

39%

Baczewski L. T., Wawro A., Domagała J., Pełka J., Szewczyk A., Nabiałek A.

Acta Physica Polonica A

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1997

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vol. 91

|

issue 2

315-319

EN

Structural and magnetic properties of Co/Cu multilayers deposited in the ultra-high vacuum molecular beam epitaxy system on glass substrates with different modulations periods were investigated. A structural characterization was performed by means of RHEED and Auger spectroscopy (in situ), small angle X-ray reflectivity and scanning tunneling microscopy. The samples obtained have a textured, polycrystalline layered structure for deposition at room temperature. Magnetization and in-plane magnetoresistance measurements were performed as a function of Cu and Co layer thicknesses. An influence of different buffers and of interface quality on magnetic properties was investigated.

Refine search results

Bioimaging with 4th Generation X-Ray Sources

Synchrotron Radiation in Biology and Medicine

X-Ray Standing Wave Technique as a Tool in the Study of the Imperfect Crystals

Metrological Applications of X-ray Waveguide Thin Film Structures in X-ray Reflectometry and Diffraction

Effective Velocity of Soliton in the Presence of a Periodic Background

Applications of Free Electron Lasers in Biology and Medicine

Old Studies with New Authors: A Discovery Ending with Retraction

Lattice Parameters of Aluminium Nitride in the Range 10-291 K

Oscillations in Reflectivity of Samples with X-ray Waveguide Layers

X-Ray and Electron-Optical Characterization of ZnTe/CdTe and ZnTe/GaAs Epitaxial Layers Obtained by the MBE Method

Study of Si-Implanted and Thermally Annealed Layers of Silicon by Using X-ray Grazing Incidence Methods

X-ray Characterization of Films Formed by Pulsed Laser Deposition on Cold Substrates from YBaCuO Targets

X-Ray and Electron-Optical Characterization of ZnSe(Co) Crystal with Natural Face

Structure and Magnetism of MBE-Grown Co/Cu Multilayers