Human mesenchymal stem cells (hMSCs) with their vast differentiation potential are very useful for cell-based regenerative medicine. To achieve sufficient numbers of cells for tissue engineering, many different methods have been used to reach the effective increase of cell proliferation. Low-energy red light provided by light emitting diodes (LEDs) have been recently introduced as a method that promoted biomodulation and proliferation of hMSCs in vitro. The purpose of this study was to find the optimum stimulatory dosimetric parameters of LED (630 nm) irradiation on the hMSCs proliferation. The energy density was 2, 3, 4, 10, 20 J/cm2 and the power density used was 7, 17 or 30 mW/cm2. Human MSCs were irradiated with single or triple exposures daily at room temperature and the cell proliferation rate was evaluated during nine days after irradiation. The results showed that after irradiation 4 J/cm2 and 17 mW/cm2 at a single dose the proliferation rate of hMSCs increased on day 5 and 9 (13% and 7%, respectively) when compared to nonirradiated cells. However, triple LED irradiation under the same parameters resulted in the decline in the cell proliferation rate on day 5, but the proliferation rate was at the same level on day 9, when compared with the cell proliferation after irradiation with a single dose. The effect of a single dose irradiation with 4 J/cm2 and 17 mW/cm2 on the proliferation of cells was the highest when the cells were irradiated in phosphate-buffered saline (PBS) instead of MSCGM culture medium.
The availability of low-cost therapeutic illuminators was one of the key factors to limit clinical use of PDT. The paper presents modern light sources which have revolutionized PDT method, contributing to its more common use. The technical parameters of different illuminators are compared. Finally, own light sources were presented and developed in Polish clinics.
Autofluorescence (AF) is the natural emission of light by intrinsic fluorophores. Oxidized mitochondrial flavins, lipofuscin and reduced nicotinamideadenine dinucleotide phosphate (NAD(P)H) are the main sources of the autofluorescence in cells upon excitation with visible light. The aim of the study was to investigate changes in the metabolism of four cell lines by monitoring their autofluorescence with a microplate reader. Autofluorescence intensities of cells were collected at two wavelengths for the excitation and fluorescence emission: for endogenous NAD(P)H at 366/450 nm, for the oxidized flavoproteins and lipofuscin at 460/540 nm. Human mesenchymal stem cells (hMSC), epithelial cells from mammary gland (MCF 10A), breast ductal carcinoma (T-47D) prostate carcinoma (DU-145) were observed daily for 16 days. The level of NAD(P)H autofluorescence did not differ among the cell lines investigated. The significant increase in oxidized flavoproteins fluorescence intensity was recorded for hMSC and ranged from 140 to 175% of control. During 28 days differentiation process, the NAD(P)H, FAD and lipofuscin fluorescence intensities were recorded every day, and the redox ratio was then calculated. The redox ratio gradually decreased during the last eight days of osteogenesis and adipogenesis. Therefore, in our opinion the NAD(P)H, FAD, and lipofuscin fluorescence emission at the wavelengths selected are the optimal parameters to be collected during the differentiation process in order to monitor the metabolism of hMSC undergoing structural and morphological changes.
LIDAR system for real-time standoff detection of bio-agents is presented and preliminary experimental results are
discussed. The detection approach is based on two independent physical phenomena:
(1) laser induced fluorescence (LIF),
(2) depolarization resulting from elastic scattering on non-spherical particles.
The device includes three laser sources, two receiving telescopes, depolarization component and spectral signature
analyzing spectrograph. It was designed to provide the stand-off detection capability at ranges from 200 m up to several
kilometers. The system as a whole forms a mobile platform for vehicle or building installation. Additionally, it's
combined with a scanning mechanics and advanced software, which enable to conduct the semi-automatic monitoring of
a specified space sector.
For fluorescence excitation, 3-rd (355 nm) and 4-th (266 nm) harmonics of Nd:YAG pulsed lasers are used. They emit
short (~6 ns) pulses with the repetition rate of 20 Hz. Collecting optics for fluorescence echo detection and spectral
content analysis includes 25 mm diameter f/4 Newton telescope, Czerny Turner spectrograph and 32-channel PMT.
Depending on the grating applied, the spectral resolution from 20 nm up to 3 nm per channel can be achieved.
The system is also equipped with an eye-safe (1.5 μm) Nd:YAG OPO laser for elastic backscattering/depolarization
detection. The optical echo signal is collected by Cassegrain telescope with aperture diameter of 12.5 mm.
Depolarization detection component based on polarizing beam-splitter serves as the stand-off particle-shape analyzer,
which is very valuable in case of non-spherical bio-aerosols sensing.
Following article presents LIDAR for stand off detection of aerosols which was constructed in Institute of
Optoelectronics in Military University of Technology. LIDAR is a DISC type system (DIfferential SCattering) and is
based on analysis of backscattering signal for two wavelengths (λ1 = 1064 nm and λ2 = 532
nm) - the first and the
second harmonic of Nd:YAG laser. Optical receiving system is consisted of aspherical mirror lens, two additional
mirrors and a system of interference filters. In detection system of LIDAR a silicon avalanche photodiode and two
different amplifiers were used. Whole system is mounted on a specialized platform designed for possibility of LIDAR
scanning movements. LIDAR is computer controlled. The compiled software enables regulation of the scanning platform
work, gain control, and control of data processing and acquisition system. In the article main functional elements of
LIDAR are shown and typical parameters of system work and construction are presented. One presented also first results
of research with use of LIDAR. The aim of research was to detect and characterize scattering aerosol, both natural and
anthropogenic one. For analyses of natural aerosols, cumulus cloud was used. For analyses of anthropogenic aerosols one
used three various pyrotechnic mixtures (DM11, M2, M16) which generate smoke of different parameters. All scattering
centers were firstly well described and theoretical analyses were conducted. Results of LIDAR research were compared
with theoretical analyses and general conclusions concerning correctness of LIDAR work and its application were
drawn.
There is considerable interest in compact pulsed high peak power laser sources emitting at wavelengths near 1.55 micrometers . Rangefinders and other applications with free space propagation could be strongly benefit of such devices. The wavelength of around 1.55 micrometers is in the eyesafe regime where significantly higher pulse energies can be used without damaging human eyes. Erbium and ytterbium doped YAG single crystals were obtained by the Czochralski method. The basis conditions of growth and the results of optical homogeneity measurements of the obtained crystals are presented. Absorption spectra of these Er3+- and Yb3+-doped YAG crystals were measured in the spectral range 190 divided by 5000 nm at room temperature. Excitation and luminescence spectra were also recorded at room temperature with a JOBIN-YVON spectro fluorometer using a diode laser as an excitation source. The measurements of the lifetime of the Er3+ ions in the upper laser level of the samples were made by the direct method with pulse excitation.
The paper describes growth of neodymium doped borate and tungstate single crystals and their optical and spectroscopic properties. Czochralski and top seeded solution growth techniques were used to crystalize Kgc1-xNdx(WO4)2 tungstate, and self-frequency doubling YAl3(BO3)4:Nd and Ca4GdO(BO3)3:Nd borates. Single crystals having good optical quality, free from inclusions, bubbles, or cracks were obtained. Transmission and luminescence spectra of investigated crystals were measured. The measurements of Nd3+ ions lifetime at the upper laser level for the samples of KGW:Nd, YAB:Nd, and GdCOB:Nd crystals were made by means of direct method with pulse excitation. The obtained results confirm usability of as-grown single crystals for construction of diode-pumped lasers.
The results of examinations of accumulation of bis-1(I- alanylo-N)-ethylo-deuteroprotoporfiryne (Ala-PP) in healthy tissues and superficial tumors of 10 patients are presented. Fluorescence imaging was carried out by means of a CCD camera, coupled with an image amplifier. As an excitation source a titanium laser was used. Contrary to healthy tissues, the tumor ones are characterized by the slight decrease in Ala-PP concentration during several days after injection of preparation what enables initial determination of a tissue character and next application of a selective therapeutic irradiation.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.