Irradiation of the rat portal vein's fragments with the He-Ne laser for 3, 5 and 10 minutes reduced the fragments tone by half. Frequency of phasic and tonic contractions did not change, their amplitude, however, increased by neatly 40% as compared with the initial level. The NO synthase blocker N-nitro-L-arginine administered prior to the irradiation had no effect on the above parameters. The data obtained suggest that the decrease of the vessel tone is due to production of the EDRF and cGMP. The increase in the amplitude of phasic and tonic contractions of the vein's smooth muscle cells is associated with an increased Ca++ entry in each contraction cycle.
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Photoacoustics
February 2025
Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Sapienza Università di Roma, Rome 00161, Italy.
A compact and robust optical excitation photoacoustic sensor with a self-integrated laser module excitation and an optimized differential resonator was developed to achieve high sensitivity and full linear range detection of carbon dioxide (CO) based on dual modes of wavelength modulated photoacoustic spectroscopy (WMPAS) and resonant frequency tracking (RFT). The integrated laser module equipped with three lasers (a quantum cascade laser (QCL), a distributed feedback laser (DFB) and a He-Ne laser) working in a time-division multiplexing mode was used as an integrated set of spectroscopic sources for detection of the designated concentration levels of CO. With the absorption photoacoustic mode, the WMPAS detection with the QCL and DFB sources was capable of CO detection at concentrations below 20 %, yielding a noise equivalent concentration (NEC) as low as 240 ppt and a normalized noise equivalent absorption coefficient (NNEA) of 4.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Agricultural, Forest and Transport Machinery, University of Life Sciences in Lublin, Głęboka 28, 20-612, Lublin, Poland.
In this paper, we propose a high-precision dual-comb ranging (DCR) method for short-distance measurement, avoiding carrier-envelope-offset locking. Cross-polarization detection is introduced, which makes better use of the intrinsic coherence of interferogram pairs over a short distance. We analyze the noise in the DCR system and propose a carrier-wave phase difference (CPD) calculation algorithm based on centroid extraction.
View Article and Find Full Text PDFPhotodiagnosis Photodyn Ther
November 2024
Department of Dermatology, Guangzhou Dermatology Hospital (Guangzhou Institute of Dermatology), Guangzhou, Guangdong 510095, China. Electronic address:
Sci Rep
November 2024
Department of Physics, Faculty of Education, Ain Shams University, Roxy, Cairo, 11757, Egypt.
The aqueous solution cast method was used to create the biodegradable polymer nanocomposite (PNC) films from a blend of poly (vinyl alcohol) PVA and poly (vinyl pyrrolidone) PVP (70/30 wt %) and FeO nanoparticles (NPs). These PNC films were characterized using X-ray diffraction, scanning electron microscopy SEM, Fourier transform infrared spectroscopy FTIR, and ultraviolet-visible spectroscopy. XRD and FTIR results indicate that Fe NPs interact with the host polymer.
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