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Institut für Physiologie und Pathophysiologie

Nonlinear Microscopy

Figure 1: SHG signals from myofibrils change under rotation of the excitation laser polarization

Second Harmonic Generation

Second harmonic generation (or frequency doubling) is an effect that can be observed in certain nonlinear optical media, which emit radiation at a doubled frequency 2w when excited by an external electric field of the frequency w. The effect is well known for a number of crystals like quartz, but was also discovered for some biological structures like collagen or skeletal muscle myosin-II.

 

We are interested in the physical properties of second harmonic generation in these biological structures and applications for tissue imaging. The SHG signal intensity, for example, depends on the fiber orientation and the polarization of the incident light. Theoretical predictions for this dependency can be derived from standard equations considering crystal symmetries and then be tested with our experimental setup.

Figure 2: Two-photon excited fluorescence of Bodipy-Fl labeled actin in skeletal muscle

Multiphoton Fluorescence

Two or more photons of an infrared laser can be absorbed simultaneously by a fluorescent molecule to promote it to an excited state. The emission wavelength is the same as for standard single photon excitation.

 

As the effect of multi-photon excitation needs high energy densities, it occures mainly in the small center of the laser focus. Fluorescence is limited to this spot, which provides multi-photon microscopes with inherent high resolution. The main advantage over confocal microscopes is the higher resolution in deep tissue layers.

 


24.10.2017       13:30   /   INF 327, Seminar Room 1

 

Hypoxia and uterine contractions: Something old and something new

Prof. Dr. Susan Wray

Dept. of Cellular and Molecular Physiology, University of Liverpool, United Kingdom

  

24.10.2017       18:00   /   INF 410 (Med. Clinic), Auditorium

 

Calcium in the heart: in and out of control

Prof. Dr. David Eisner

Manchester Institute for Collaborative Research on Ageing, University of Manchester, United Kingdom


(seminar of Heidelberg University Hospital and German Center for Cardiovascular Disease (DZHK); host: Prof. Dr. M. Hecker, Inst. of Physiology and Pathophysiology, Heidelberg University)

  

Neue Publikationen

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Allosteric inhibition of carnosinase (CN1) by inducing a conformational shift. J Enzyme Inhib Med Chem. 2017 Dec;32(1):1102-1110. doi: 10.1080/14756366.2017.1355793.

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Transcription factor decoy technology: a therapeutic update. Biochem Pharmacol. 2017 Nov 15;144:29-34. doi: 10.1016/j.bcp.2017.06.122. Epub 2017 Jun 19. Review.

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Heteromeric channels formed by TRPC1, TRPC4 and TRPC5 define hippocampal synaptic transmission and working memory. EMBO J. 2017 Sep 15;36(18):2770-2789. doi: 10.15252/embj.201696369. Epub 2017 Aug 8

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NO-sGC Pathway Modulates Ca2+ Release and Muscle Contraction in Zebrafish Skeletal Muscle. Front Physiol. 2017 Aug 23;8:607. doi: 10.3389/fphys.2017.00607. eCollection 2017.


Institut für
Physiologie und Pathophysiologie

Universität Heidelberg

Im Neuenheimer Feld 326

69120 Heidelberg

Telefon:+49 6221 54-4056
Telefax:+49 6221 54-6364
E-Mail:susanne.bechtel@
physiologie.uni-heidelberg.de