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We report on a flat and broadband thulium-doped amplified spontaneous emission (ASE) fiber source working around 1.85 µm in the eye-safe spectral region. Core-pumped thulium fibers were prepared in-house using the modified chemical vapor deposition method. The amplified spontaneous emission source in a backward direction with respect to the pump and in a single-ended configuration produces stable, non-polarized radiation with an output power of up to 280 mW, corresponding to a slope efficiency of about 36% with respect to the pump power. To the best of our knowledge, the device reported herein is the broadest ASE source based on Tm-doped fiber without internal spectral filtering with an output power exceeding 90 mW and full width at half-maximum of the spectrum greater than 155 nm.

Self-swept erbium fiber laser emitting around 1.56 μm is reported in detail. Both sweep directions were registered: pointing toward longer and shorter wavelengths, redshift and blueshift sweeping, respectively. We describe method of determining the direction of the wavelength drift using the monochromator based optical spectrum analyzer. Possible root for this sweeping regime, i.e., the gain modulation along active fiber, is discussed with the help of a simple model calculating the overall cavity gain that can predict the direction of the laser wavelength sweeping.

We demonstrated two methods of increasing the bandwidth of a broadband light source based on amplified spontaneous emission in thulium-doped fibres. Firstly, we have shown by means of a comprehensive numerical model that the full-width at half maximum of the thulium-doped fibre based broadband source can be more than doubled by using specially tailored spectral filter placed in front of the mirror in a double-pass configuration of the amplified spontaneous emission source. The broadening can be achieved with only a small expense of the output power. Secondly, we report results of the experimental thulium-doped fibre broadband source, including fibre characteristics and performance of the thulium-doped fibre in a ring laser setup. The spectrum broadening was achieved by balancing the backward amplified spontaneous emission with back-reflected forward emission.

Lung transplant recipients are encouraged to perform self‐management behaviors, including (i) monitoring health indicators, (ii) adhering to their regimen, and (iii) reporting abnormal health indicators to the transplant coordinator, yet performance is suboptimal. When hospital discharge was imminent, this two‐group trial randomized 201 recipients to use either the mobile health (mHealth) intervention (n = 99) or usual care (n = 102), to compare efficacy for promoting self‐management behaviors (primary outcomes) and self‐care agency, rehospitalization, and mortality (secondary outcomes) at home during the first year after transplantation. The mHealth intervention group performed self‐monitoring (odds ratio [OR] 5.11, 95% confidence interval [CI] 2.95–8.87, p < 0.001), adhered to medical regimen (OR1.64, 95% CI1.01–2.66, p = 0.046), and reported abnormal health indicators (OR8.9, 95% CI3.60–21.99, p < 0.001) more frequently than the usual care group. However, the two groups did not differ in rehospitalization (OR0.78, 95% CI0.36–1.66, p = 0.51) or mortality (hazard ratio 1.71, 0.68–4.28, p = 0.25). The positive impact of the mHealth intervention on self‐management behaviors suggests that the intervention holds promise and warrants further testing. This randomized controlled trial of lung recipients followed for one year after transplant demonstrates that a mobile health intervention is superior to usual care in promoting self‐management behaviors, though the two groups did not differ in health outcomes, suggesting that mHealth interventions hold promise but warrant further testing.

Lung transplant recipients are encouraged to perform self‐management behaviors, including (i) monitoring health indicators, (ii) adhering to their regimen, and (iii) reporting abnormal health indicators to the transplant coordinator, yet performance is suboptimal. When hospital discharge was imminent, this two‐group trial randomized 201 recipients to use either the mobile health (mHealth) intervention (n = 99) or usual care (n = 102), to compare efficacy for promoting self‐management behaviors (primary outcomes) and self‐care agency, rehospitalization, and mortality (secondary outcomes) at home during the first year after transplantation. The mHealth intervention group performed self‐monitoring (odds ratio [OR] 5.11, 95% confidence interval [CI] 2.95–8.87, p < 0.001), adhered to medical regimen (OR 1.64, 95% CI 1.01–2.66, p = 0.046), and reported abnormal health indicators (OR 8.9, 95% CI 3.60–21.99, p < 0.001) more frequently than the usual care group. However, the two groups did not differ in rehospitalization (OR 0.78, 95% CI 0.36–1.66, p = 0.51) or mortality (hazard ratio 1.71, 0.68–4.28, p = 0.25). The positive impact of the mHealth intervention on self‐management behaviors suggests that the intervention holds promise and warrants further testing.

The measurement of pH in small objects (cells, drops of liquid etc.) using optical fluorescence-based sensors on optical fiber tapers is one of the most widely used optical techniques. In these sensors the diameter of the taper can play important role for collecting fluorescence from tested samples. This paper presents results of experimental measurements of fluorescence intensity of dye sensitive to pH in a solution that is excited by a blue laser. The fluorescence of the dye is collected by a taper tip. The fiber tips were prepared from a graded-index fiber with a core diameter of 50 m. Measurements with taper tips of different diameters have allowed us to estimated a limited tip diameter necessary for collecting any fluorescence form the dye solution on a level of about 5m.

This paper deals with a steering-wheel microstructure optical fibre designed prepared and tested for detection of gaseous analytes. The inner structure of the steering-wheel microstructure fibre consists of a thin silica core that is surrounded by three cladding holes. Numerical simulations showed that the evanescent wave of the guided fundamental mode at a wavelength of 1550 nm penetrates into the cladding holes. The calculated overlap of the evanescent wave of guided mode with the cladding holes of 0.78% can suitably be employed for gaseous analytes detection. The prepared steeringwheel microstructure fibre was experimentally tested for detection of toluene vapors flowing in the cladding holes of the fibre. It has been proved that this type of microstructure fibre can be used for detection of gaseous analytes such as toluene in nitrogen or in air in concentrations of about 0.1 mol.%.

The tumor suppressor gene Trp53 (also known as p53) is the most frequently mutated gene in human cancers. p53 is induced in response to DNA damage and effects a G₁ cell cycle arrest. It is believed that p53 plays a key role in maintaining genomic integrity following exposure to DNA-damaging agents. We determined the frequency of spontaneous and DNA damage-induced homologous intrachromosomal recombination in p53-deficient mouse embryos. Homologous intrachromosomal recombination events resulting in deletions at the pink eyed unstable (p^un) locus result in reversion to the p gene. Reversions occurring in embryonic premelanocytes give rise to black spots on the gray fur of the offspring. Pregnant C57BL/6J p^un/p^un p53^+/- mice were exposed to X-rays (1 Gy) or administered benzo[a]pyrene (B[a]P; 30 or 150 mg/kg i.p.) 10 days after conception. Frequencies of spontaneous p^un reversions in p53^-/- and p53^+/- animals were not significantly different compared with their wild-type littermates. X-ray treatment increased the recombination frequency in wild-type and p53^+/-, but surprisingly not in p53^-/- offspring. In contrast, B[a]P treatment caused a dose-dependent increase in p^un reversion frequencies in all three genotypes. Western blot analysis of embryos indicated that p53 protein levels increased ~3-fold following X-ray treatment, while B[a]P had no effect on p53 expression. These results are in agreement with the proposal that p53 is involved in the DNA damage response following X-ray exposure and suggest that X-ray-induced double-strand breaks are processed differently in p53^-/- animals.

The tumor suppressor gene Trp53 (also known as p53) is the most frequently mutated gene in human cancers. p53 is induced in response to DNA damage and effects a G(1) cell cycle arrest. It is believed that p53 plays a key role in maintaining genomic integrity following exposure to DNA-damaging agents. We determined the frequency of spontaneous and DNA damage-induced homologous intrachromosomal recombination in p53-deficient mouse embryos. Homologous intrachromosomal recombination events resulting in deletions at the pink eyed unstable (p(un)) locus result in reversion to the p gene. Reversions occurring in embryonic premelanocytes give rise to black spots on the gray fur of the offspring. Pregnant C57BL/6J p(un)/p(un) p53(+/-) mice were exposed to X-rays (1 Gy) or administered benzo¿apyrene (B¿aP; 30 or 150 mg/kg i.p.) 10 days after conception. Frequencies of spontaneous p(un) reversions in p53(-/-) and p53(+/-) animals were not significantly different compared with their wild-type littermates. X-ray treatment increased the recombination frequency in wild-type and p53(+/-), but surprisingly not in p53(-/-) offspring. In contrast, B¿aP treatment caused a dose-dependent increase in p(un) reversion frequencies in all three genotypes. Western blot analysis of embryos indicated that p53 protein levels increased approximately 3-fold following X-ray treatment, while B¿aP had no effect on p53 expression. These results are in agreement with the proposal that p53 is involved in the DNA damage response following X-ray exposure and suggest that X-ray-induced double-strand breaks are processed differently in p53(-/-) animals.

An experimental study of non-linear confinement of transient motions in a flexible structure consisting of two weakly coupled cantilever beams with active grounding non-linearities has been carried out. The experimental fixture and the control methodology used for implementing the active non-linearities are discussed in detail. It has been found that the system with active non-linearities possesses motion confinement properties, that is, transient motions originating at one of the beams become spatially confined mainly to the directly excited beam, with small amounts of vibrational energy “leaking” to the unexcited one. As the damped motion decays the non-linear effects diminish and the motion confinement phenomenon becomes less evident. The experimental results are in agreement with analytical predictions. The implementation of non-linear motion confinement in vibration and shock isolation designs of repetitive systems is discussed.

Adult rat hepatocytes were cultured in serum free chemically defined MX-83 medium. Fibronectin mRNA expression accumulated to high levels in primary cultures of hepatocytes and transcripts were detectable even after 2 hrs. However, the presence of phenobarbital (PB) in the culture medium led to a dose-dependent decrease in fibronectin mRNA levels concomitant to an increase of cytochrome P450-2B1 (CYP2B1) mRNA, whereas the coaddition of EGF reversed the suppressive effect of PB in a similar dose-dependent manner. Culturing hepatocytes on a fibronectin matrix partially inhibited the accumulation of cytochrome CYP2B-dependent pentoxyresorufin-O-depentylase (PROD) activities in the presence of the inductor PB.Copyright 1993, 1999 Academic Press

The metabolic fate of cotinine, the major metabolite of nicotine, was studied in phenobarbital-induced and non-induced isolated perfused rat lung and liver and in isolated hepatocytes of rats and mice. The non-induced lung tissue showed low cotinine metabolizing capacity while the perfused liver was approximately four times more active. After phenobarbital pretreatment the metabolism of cotinine was increased eight-fold in the intact liver. A substantial increase in cotinine metabolism was also found in isolated hepatocytes from PB-induced rats and in cultured mouse hepatocytes grown in a medium supplemented with PB. This was paralleled by an increased formation of cotinine-N-oxide which could be inhibited by 100 µM metyrapone. In contrast, the pulmonary elimination of cotinine was not affected by PB. A dominant role of primary N-oxidation of nicotine compared to C-oxidation was apparent in non-induced rat liver. After PB treatment the rate of nicotine-N'-oxide formation dropped markedly while the cotinine related pathways were increased causing an inversion of the N- to C-oxidation ratio. In the lung, cotinine formation was the preferred metabolic pathway of nicotine already in non-induced organs. The pattern of nicotine metabolites was not altered by PB induction. In conscious PB-induced rats receiving nicotine orally or intravenously, 3'-hydroxycotinine was found as the main urinary metabolite of nicotine while only a small fraction was excreted as cotinine-N-oxide. This discrepancy between the profile of nicotine metabolites in perfused liver and lung and in the urine in vivo indicates that extrahepatic organs other than the lung may be important sites of cotinine metabolism.

Summary Steady-state nonlinear motion confinement is experimentally studied in a system of weakly coupled cantilever beams with active stiffness nonlinearities. Quasistatic swept-sine tests are performed by periodically forcing one of the beams at frequencies close to the first two closely spaced modes of the system, and experimental nonlinear frequency response curves for certain nonlinearity levels are generated. Of particular interest is the detection of strongly localized steady-state motions, wherein vibrational energy becomes spatially confined mainly to the directly excited beam. Such motions exist in neighborhoods of strongly localized antiphase nonlinear normal modes (NNMs) which bifurcate from a spatially extended NNM of the system. Steady-state nonlinear motion confinement is an essentially nonlinear phenomenon with no counterpart in linear theory, and can be implemented in vibration and shock isolation designs of mechanical systems.