Search results

1

Statistical Physics of Bose-Einstein Condensation

100%

Gajda M., Rzążewski K.

Acta Physica Polonica A

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2001

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vol. 100

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issue Supplement

7-28

EN

We review a progress in understanding of statistical properties of a quantum degenerate Bose gas. We show how the Maxwell demon ensemble helps to compute fluctuations of the Bose-Einstein condensate of an ideal Bose gas according to the microcanonical ensemble. Then, we review a method of measuring these fluctuations. Using a soluble model of interacting Bose gas we also stress the importance of higher-order correlation functions. Finally, we review our novel computational method of studying an interacting Bose gas near its critical temperature.

2

Soluble Model of Interacting Bosons Trapped in Harmonic Potential: Quality of Bogoliubov Approximation

81%

Załuska-Kotur M., Gajda M., Mostowski J.

Acta Physica Polonica A

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2001

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vol. 100

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issue 4

485-504

EN

We study a system of trapped bosonic particles interacting by model harmonic forces. Our model allows for a detailed examination of the notion of an order parameter (a condensate wave function). By decomposing a single particle density matrix into coherent eigenmodes we study an effect of interaction on the condensate. We show that sufficiently strong interactions cause that the condensate disappears even if the whole system is in its lowest energy state. In the second part of our paper we discuss the validity of the Bogoliubov approximation by comparing its predictions with results inferred from the exactly soluble model. In particular we examine an energy spectrum, occupation, and fluctuations of the condensate. We conclude that Bogoliubov approach gives a quite accurate description of the system in the limit of weak interactions.

3

The effect of TCDD dioxin on the rat liver in biochemical and histological assessment

61%

Czepiel J., Biesiada G., Gajda M., Szczepanski W., Szypula K., Dabrowski Z., Mach T.

Folia Biologica

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2010

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vol. 58

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issue 1-2

85-90

EN

Eighteen maleWistar rats were divided into 3 groups of 6 animals each. Two groups received different intraperitoneal doses of TCDD (0.75 and 8Fg) in DMSO solution and the third group (control) received only DMSO on days 0, 7 and 14. On day 21 the animals were sacrificed, and then blood tests, pathological examination and CYP1A1 activity measurement were performed. In rats that received a high dose of dioxin (8 Fg) hepatic lobules revealed parenchymal degeneration and vacuolization of hepatocytes was observed, and also an increased CYP reaction was found in central parts of lobules, around the central vein. The reaction in control and low dose groups was weak. The resorufin level was significantly (P<0.05) higher in the group receiving a low dose of dioxin as compared to the control group. The study confirmed that TCDD damages the rat liver in a dose-dependent manner. Administration of high TCDD doses causing major liver damage also damaged CYP1A1 (based on higher resorufin levels in epiluminescence). TCDD activates CYP1A1, which was confirmed by increased immunohistochemical reactivity of central areas of hepatic lobules.

4

Harmonically Trapped Classical Gas under Critical Rotation

61%

Chwedeńczuk J., Ziń P., Trippenbach M., Dąbrowska B., Gajda M., Rzążewski K.

Acta Physica Polonica A

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2003

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vol. 104

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issue 5

399-407

EN

We study one- and two-dimensional systems of two interacting particles in a time dependent harmonic potential. In a case of one-dimensional geometry a frequency of the potential varies periodically, while in the two-dimen- sional~case the harmonic potential rotates with a constant angular velocity. We show that depending on the driving frequency the distance between the particles can either explode or stay bound. Repulsive interaction can prevent the explosion, which seems quite counter-intuitive. Our work is related to Ecole Normale Supérieure experiment and shows that the effect found there is purely classical.

5

Chemical Composition of Atherosclerotic Plaques οf apoE/LDLR-Double Knockout Mice by Synchrotron Radiation FTIR Microspectroscopy

52%

Kowalska J., Gajda M., Kwiatek W., Franczyk-Żarów M., Kostogrys R., Chłopicki S., Sandt C., Dumas P.

Acta Physica Polonica A

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2012

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vol. 121

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issue 2

555-560

EN

Atherosclerosis is a multietiological inflammatory disease of large and medium-sized arteries of increasing incidence in westernized countries. The aim of this study was to identify the biochemical changes during the progression of atherosclerosis by synchrotron radiation Fourier transform infrared microspectroscopy in atheromas of apoE/LDLR^{-/-} mice fed egg-rich diet supplemented or not with angiotensin converting enzyme inhibitor perindopril. Synchrotron radiation Fourier transform infrared microspectroscopy technique was used to obtain information at high spatial resolution about the distribution of proteins (C-N, N-H, CO for amide I and amide II bands), lipids (CH_2, CH_3 bands) as well as mineral deposits (calcium carbonates and phosphates). Total contents of lipids and proteins were found to be significantly lower in animals treated with the diet and perindopril. An increase in saturation level of lipids was observed in animals fed with egg-rich diet when compared to the normal diet and perindopril treatment, which did not inhibit this effect. Moreover, a significant change in the secondary structure of proteins (ratio between absorption bands 1634 cm^{-1}/1656 cm^{-1} attributed to β-type and α-type, respectively) was observed in both experimental groups in comparison with the control. Principal component analysis was used to analyse the recorded spectra. It has revealed that higher content of phosphates (wavenumber range 950-1020 cm^{-1}) was observed between egg-rich diet fed animals and the control group.

6

Distinguishing Prostate Cancer from Hyperplasia

52%

Kwiatek W., Banaś A., Banaś K., Podgórczyk M., Dyduch G., Falkenberg G., Gajda M., Cichocki T.

Acta Physica Polonica A

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2006

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vol. 109

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issue 3

377-381

EN

The prostate gland is the most common site of neoplastic disorders in men. The knowledge of the pathogenesis of benign prostate hyperplasia and prostate cancer is still under investigation. X-ray fluorescence analysis using synchrotron radiation seems to be an appropriate technique to study the elemental composition of biological tissues. The measurements presented in this paper were carried out on the L-beam line at the HASYLAB, DESY (Germany). The observed concentrations of Fe, Cu, Mn, and Zn are significantly higher in cancerous tissues, as compared to normal and hyperplastic ones. Our results reveal also the existence of the two types of hyperplasia.

Refine search results

Statistical Physics of Bose-Einstein Condensation

Soluble Model of Interacting Bosons Trapped in Harmonic Potential: Quality of Bogoliubov Approximation

The effect of TCDD dioxin on the rat liver in biochemical and histological assessment

Harmonically Trapped Classical Gas under Critical Rotation

Chemical Composition of Atherosclerotic Plaques οf apoE/LDLR-Double Knockout Mice by Synchrotron Radiation FTIR Microspectroscopy

Distinguishing Prostate Cancer from Hyperplasia