Zeitschriftenartikel: „Pulsing light“

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Hashmi, Javad T., Ying-Ying Huang, Sulbha K. Sharma, Divya Balachandran Kurup, Luis De Taboada, James D. Carroll und Michael R. Hamblin. „Effect of pulsing in low-level light therapy“. Lasers in Surgery and Medicine 42, Nr. 6 (20.07.2010): 450–66. http://dx.doi.org/10.1002/lsm.20950.

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Chuntul, A. V., und A. P. Kozlovsky. „PULSING LIGHT STIMULATION IN STATE CORRECTION OF AVIATION PERSONNEL“. Aerospace and Environmental Medicine 52, Nr. 5 (2018): 47–52. http://dx.doi.org/10.21687/0233-528x-2018-52-5-47-52.

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Forestini, M., und C. Charbonnel. „Nucleosynthesis of light elements inside thermally pulsing AGB stars“. Astronomy and Astrophysics Supplement Series 123, Nr. 2 (Juni 1997): 241–72. http://dx.doi.org/10.1051/aas:1997348.

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Kamuri, Mohd, Zurina Zainal Abidin, Mohd Yaacob, Mohd Hamidon, Nurul Md Yunus und Suryani Kamarudin. „Separation and Detection of Escherichia coli and Saccharomyces cerevisiae Using a Microfluidic Device Integrated with an Optical Fibre“. Biosensors 9, Nr. 1 (14.03.2019): 40. http://dx.doi.org/10.3390/bios9010040.

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This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μ L min − 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min − 1 at a constant frequency, voltage, and a low conductivity.

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Barolet, Daniel, Pascale Duplay, Hélène Jacomy und Mathieu Auclair. „Importance of pulsing illumination parameters in low-level-light therapy“. Journal of Biomedical Optics 15, Nr. 4 (2010): 048005. http://dx.doi.org/10.1117/1.3477186.

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Begin, I., B. Bhatia, K. Rao, R. Keyston, J. T. Pierson, N. Neveu, F. Cote et al. „28PREGNANCIES RESULTED FROM GOAT NT EMBRYOS PRODUCED BY FUSING COUPLETS IN THE PRESENCE OF LECTIN“. Reproduction, Fertility and Development 16, Nr. 2 (2004): 136. http://dx.doi.org/10.1071/rdv16n1ab28.

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The procedure of nuclear transfer (NT) using somatic cells remains inefficient partly due to low fusion rates between donor cells and recipient ooplasm. Lectin is a glycoprotein which specifically binds to carbohydrates to induce a tight contact of membrane to membrane (Booth et al., 2001 Cloning and Stem Cells, 3, 139–159). The purpose of this study was to examine the fusion rates and developmental competence of NT embryos following pre-incubation of couplets in medium containing lectin prior to electrical pulsing. Oocytes were collected by laparoscopic ovum pick-up from hormonally primed goats or by aspiration from culled goat ovaries, and cultured for maturation at 38.5°C, 5% CO2. At approximately 24h after the onset of IVM, the cumulus cells were stripped off by brief vortexing in medium containing 0.2% hyaluronidase. Oocytes with first polar bodies were selected for NT. Successful enucleation was confirmed by the absence of MII chromosomes in ooplasm by means of brief exposure of the Hoechst 33342-stained oocytes to UV light. Three cumulus-granulosa cell lines from transgenic goats were used as donor cells. They were cultured to confluency in DMEM+20% FCS for 6 days prior to NT. Individual donor cells were transferred into the perivitelline space of the enucleated oocytes. Couplets were incubated for 15 minutes in TCM199+10% FCS containing 75 or 150μgmL−1 lectin (L-9132 Sigma, St.Louis, MO, USA) prior to being subjected to electrical pulsing (lectin treatment) with one DC pulse at 2.4kV/cm (1st pulsing). The fusion rate was determined 40–60 minutes after the 1st electric pulsing. Non-fused couplets were exposed to a 2nd pulsing. Approximately 30 minutes later, non-fused couplets were exposed to a 3rd pulsing. Couplets without the lectin treatment served as controls. Reconstructed embryos were activated with 5μM ionomycin followed by 5h of incubation in 10μgmL−1 cycloheximide with 7.5μgmL−1 cytochalasin B. A group of 10 to 13 embryos was transferred into a recipient after 12 to 14h of culture in G1.3. Statistical analysis was performed using the χ2 analysis. Results are shown in the following table. This study demonstrated that fusion rate could be improved by pre-incubating couplets in the medium containing 150μgmL−1 lectin prior to electrical pulsing and the embryos derived from the lectin treatment could establish the early pregnancies.

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Lee, Jong-Sung, Dae-Hee Lee, Sung-Jin Kim und Chang-Heon Oh. „An LED-based visible light communication system for multicast“. Indonesian Journal of Electrical Engineering and Computer Science 13, Nr. 1 (01.01.2019): 265. http://dx.doi.org/10.11591/ijeecs.v13.i1.pp265-271.

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<p>Visible Light Communication is a communication method that transmits data through light by pulsing an LED at high speed, performing broadcast communication for all devices existing in its coverage. Broadcast-based Visible Light Communication is limited to application to Internet of Things services, where various applications exist, although all receivers can communicate within the range of light sources. Therefore, this paper proposes an LED based Visible Light Communication system for multicast. The proposed system performs individual multicast by participating in communication only with receivers configured to use a specified ID value input at the transmitting side during data transmission. Experimental results show that the receiver can receive files individually according to a specified ID value.</p>

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Mous, D. J. W., J. Visser und R. G. Haitsma. „A nanosecond pulsing system for MeV light ions using a 2 MV TandetronTM“. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 219-220 (Juni 2004): 490–93. http://dx.doi.org/10.1016/j.nimb.2004.01.108.

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Corbet, R. H. D., M. J. Coe, K. E. McGowan, M. P. E. Schurch, L. J. Townsend, J. L. Galache und F. E. Marshall. „Properties of X-ray binaries in the Magellanic Clouds from RXTE and Chandra observations“. Proceedings of the International Astronomical Union 4, S256 (Juli 2008): 361–66. http://dx.doi.org/10.1017/s1743921308028718.

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AbstractThe X-ray binary population of the SMC is very different from that of the Milky Way consisting, with one exception, entirely of transient pulsating Be/neutron star binaries. We have now been monitoring these SMC X-ray pulsars for over 10 years using the Rossi X-ray Timing Explorer with observations typically every week. The RXTE observations have been complemented with surveys made using the Chandra observatory. The RXTE observations are non-imaging but enable detailed studies of pulsing sources. In contrast, Chandra observations can provide precise source locations and detections of sources at lower flux levels, but do not provide the same timing information or the extended duration light curves that RXTE observations do. We summarize the results of these monitoring programs which provide insights into both the differences between the SMC and the Milky Way, and the details of the accretion processes in X-ray pulsars.

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Bird, Jonathan C., und Marc H. Pinsonneault. „A BOUND ON THE LIGHT EMITTED DURING THE THERMALLY PULSING ASYMPTOTIC GIANT BRANCH PHASE“. Astrophysical Journal 733, Nr. 2 (09.05.2011): 81. http://dx.doi.org/10.1088/0004-637x/733/2/81.

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Starovoytov, Artem, Jung Choi und H. Sebastian Seung. „Light-Directed Electrical Stimulation of Neurons Cultured on Silicon Wafers“. Journal of Neurophysiology 93, Nr. 2 (Februar 2005): 1090–98. http://dx.doi.org/10.1152/jn.00836.2004.

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Dissociated neurons cultured in vitro can serve as a model system for studying the dynamics of neural networks. Such studies depend on techniques for stimulating patterns of neural activity. We show a technique for extracellular stimulation of dissociated neurons cultured on silicon wafers. When the silicon surface is reverse biased, electrical current can be generated near any neuron by pulsing a laser. Complex spatiotemporal stimulation patterns can be produced by directing a single beam with an acousto-optic deflector. The technique can generate a stimulating current at any location in the culture. This contrasts with multielectrode arrays (MEAs), which can stimulate only at fixed electrode locations. To characterize reliability and spatial selectivity of stimulation, we used intracellular (patch-clamp) recordings to monitor the effect of targeted laser pulses on cultured hippocampal neurons. Action potentials could be stimulated with submillisecond precision and 100-micron spatial resolution at rates exceeding 100 Hz. Optimal control parameters for stimulation are discussed.

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Martínez-García, Eric E., Gustavo Bruzual, Rosa A. González-Lópezlira und Lino H. Rodríguez-Merino. „On the Thermally Pulsing Asymptotic Giant Branch Contribution to the Light of Nearby Disk Galaxies“. Astrophysical Journal 908, Nr. 1 (01.02.2021): 110. http://dx.doi.org/10.3847/1538-4357/abce68.

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Sajadian, Sedighe, und Richard Ignace. „Microlensing of radially pulsating stars“. Monthly Notices of the Royal Astronomical Society 494, Nr. 2 (03.04.2020): 1735–43. http://dx.doi.org/10.1093/mnras/staa837.

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ABSTRACT In this paper, we study the microlensing of radially pulsating stars. It is possible to discern and characterize the properties of distant, faint pulsating stars using high-cadence microlensing observations. By combining the stellar variability period with microlensing, we can obtain the source distance, type and radius, and we can better determine the lens parameters. Considering the variations in the radius and surface temperature of radially pulsating stars periodically, their microlensing light curves can be obtained by multiplying the magnification factor with a variable finite size effect by the intrinsic brightness curves of the pulsing source. The variable finite size of the source due to pulsation can be significant for transit and single microlensing with caustic-crossing features. This type of deviation in the magnification factor is considerable when the ratio of the source radius to the projected lens–source distance is in the range of ρ⋆/u ∈ [0.4, 10] and when its duration is short and of the same order as the time of crossing the source radius. Other deviations due to variable source intensity and its area make coloured and periodic deviations, which are asymmetric with respect to the signs of the pulsation phase. The positive phase makes deviations with larger amplitude than the negative phase. These deviations dominate in filters with short wavelengths (e.g. the B band). The position of the magnification peaks in the microlensing of variable stars varies and this displacement differs in different filters.

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Kaladchibachi, Sevag, David C. Negelspach, Jamie M. Zeitzer und Fabian Fernandez. „Optimization of circadian responses with shorter and shorter millisecond flashes“. Biology Letters 15, Nr. 8 (August 2019): 20190371. http://dx.doi.org/10.1098/rsbl.2019.0371.

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Recent work suggests that the circadian pacemaker responds optimally to millisecond flashes of light, not continuous light exposure as has been historically believed. It is unclear whether these responses are influenced by the physical characteristics of the pulsing. In the present study, Drosophila ( n = 2199) were stimulated with 8, 16 or 120 ms flashes. For each duration, the energy content of the exposure was systematically varied by changing the pulse irradiance and the number of stimuli delivered over a fixed 15 min administration window (64 protocols surveyed in all). Results showed that per microjoule invested, 8 ms flashes were more effective at resetting the circadian activity rhythm than 16- and 120 ms flashes (i.e. left shift of the dose–response curve, as well as a higher estimated maximal response). These data suggest that the circadian pacemaker's photosensitivity declines within milliseconds of light contact. Further introduction of light beyond a floor of (at least) 8 ms leads to diminishing returns on phase-shifting.

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Rahvalov, V., D. Spoiala und V. Prilepov. „The Effect of the Impulse IR Laser Radiation Upon the Mechanical Properties of Thick Films of C60“. Modern Physics Letters B 17, Nr. 10n12 (20.05.2003): 697–700. http://dx.doi.org/10.1142/s021798490300572x.

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The study of mechanical properties of crystals under exterior factors gives important information on the structure in the body of a crystal. So, for example, exterior magnetic field ~ 1–10 T brings about change in the plastic properties in dielectric crystals and polymers. The influence of pulsing magnetic field more than 10 ΔH on the change of a microhardness monocrystal C60 is also revealed. In the present work the influence of another type of exterior effect in the form of pulsing laser irradiation upon mechanical parameters is studied. The mechanical parameters, the microhardness and acoustic emission, are studied under microindentation. The study is done on thick films C60 on a quartz substrate; the thickness of the film C60 ~ 3 μm. In order to prevent photoboosted oxidizing, the measuring of a microhardness was performed in darkness with a red light filter on the PMT-3 device. The experiments for the study of the acoustic emission (Å) were also carried out with microindentation C60 and the dependences Å from the energy of laser bundle are received. An explanation is offered of a similar dependence of microhardness bound with the dislocation mechanism of plastic deformation.

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Li, Jianlang, Ken-ichi Ueda, Mitsuru Musha und Akira Shirakawa. „Residual pump light as a probe of self-pulsing instability in an ytterbium-doped fiber laser“. Optics Letters 31, Nr. 10 (15.05.2006): 1450. http://dx.doi.org/10.1364/ol.31.001450.

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Meziane, Belkacem. „Non-linear structure of the light-intensity-output versus pump-input characteristics in self-pulsing lasers“. Optical and Quantum Electronics 46, Nr. 2 (04.09.2013): 305–17. http://dx.doi.org/10.1007/s11082-013-9761-6.

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Platonova, Ganna, Dalibor Štys, Pavel Souček, Kirill Lonhus, Jan Valenta und Renata Rychtáriková. „Spectroscopic Approach to Correction and Visualisation of Bright-Field Light Transmission Microscopy Biological Data“. Photonics 8, Nr. 8 (13.08.2021): 333. http://dx.doi.org/10.3390/photonics8080333.

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The most realistic information about a transparent sample such as a live cell can be obtained using bright-field light microscopy. Under high-intensity pulsing LED illumination, we captured a primary 12-bit-per-channel (bpc) response from an observed sample using a bright-field microscope equipped with a high-resolution (4872 × 3248) image sensor. In order to suppress data distortions originating from the light interactions with elements in the optical path, poor sensor reproduction (geometrical defects of the camera sensor and some peculiarities of sensor sensitivity), we propose a spectroscopic approach for the correction of these uncompressed 12 bpc data by simultaneous calibration of all parts of the experimental arrangement. Moreover, the final intensities of the corrected images are proportional to the photon fluxes detected by a camera sensor. It can be visualized in 8 bpc intensity depth after the Least Information Loss compression.

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Simoni, F., G. Cipparrone, I. C. Khoo und C. Umeton. „Self-pulsing of the laser light transmitted by a nonlinear liquid-crystal interface near the phase transition“. Optics Letters 13, Nr. 10 (01.10.1988): 886. http://dx.doi.org/10.1364/ol.13.000886.

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Curtis, Angharad, Kang Li, Mohammed Ali und Nigel Copner. „The Optical Properties of Indocyanine Green suspended in Solution as Observed under Near Infrared LED and LASER Light Conditions“. International journal of Science and Engineering Applications 10, Nr. 5 (28.04.2021): 080–89. http://dx.doi.org/10.7753/ijsea1005.1005.

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The use of Indocyanine Green (ICG) as a fluorescent marker at Near Infrared (NIR) excitation wavelengths is well established in clinical imaging. Typical systems comprise multiple LED sources for optimal imaging which can result in unnecessary energy transfer to patients and contribute to tissue damage. An experimental setup comprising a 780 nm excitation channel generating up to 10 mW of optical power is used in order to determine if there is potential to exploit the optical properties of ICG, in order to reduce the total excitation power through pulsing. We demonstrate in this work that a single 1.6 Megapixel CMOS camera with quantum efficiency of less than 30% is appropriate to capture both fluorescent and non-fluorescent landmarks at NIR wavelengths. Experimental results verify that all ICG solutions tested yielded detectable fluorescence and that degradation of fluorescence intensity over time is multifaceted.

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Fotaki, Marianna, Kate Kenny und Sheena J. Vachhani. „Thinking critically about affect in organization studies: Why it matters“. Organization 24, Nr. 1 (Januar 2017): 3–17. http://dx.doi.org/10.1177/1350508416668192.

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Affect holds the promise of destabilizing and unsettling us, as organizational subjects, into new states of being. It can shed light on many aspects of work and organization, with implications both within and beyond organization studies. Affect theory holds the potential to generate exciting new insights for the study of organizations, theoretically, methodologically and politically. This Special Issue seeks to explore these potential trajectories. We are pleased to present five contributions that develop such ideas, drawing on a wide variety of approaches, and invoking new perspectives on the organizations we study and inhabit. As this Special Issue demonstrates, the world of work offers an exciting landscape for studying the ‘pulsing refrains of affect’ that accompany our lived experiences.

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Parameswaran, Ramya, Kelliann Koehler, Menahem Y. Rotenberg, Michael J. Burke, Jungkil Kim, Kwang-Yong Jeong, Barbara Hissa et al. „Optical stimulation of cardiac cells with a polymer-supported silicon nanowire matrix“. Proceedings of the National Academy of Sciences 116, Nr. 2 (11.12.2018): 413–21. http://dx.doi.org/10.1073/pnas.1816428115.

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Electronic pacemakers can treat electrical conduction disorders in hearts; however, they are invasive, bulky, and linked to increased incidence of infection at the tissue–device interface. Thus, researchers have looked to other more biocompatible methods for cardiac pacing or resynchronization, such as femtosecond infrared light pulsing, optogenetics, and polymer-based cardiac patches integrated with metal electrodes. Here we develop a biocompatible nongenetic approach for the optical modulation of cardiac cells and tissues. We demonstrate that a polymer–silicon nanowire composite mesh can be used to convert fast moving, low-radiance optical inputs into stimulatory signals in target cardiac cells. Our method allows for the stimulation of the cultured cardiomyocytes or ex vivo heart to beat at a higher target frequency.

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Gao, Jun, Jinsong Zhang, Chunxia He und Qirui Wang. „Effects of light spectra and 15N pulses on growth, leaf morphology, physiology, and internal nitrogen cycling in Quercus variabilis Blume seedlings“. PLOS ONE 16, Nr. 7 (15.07.2021): e0243954. http://dx.doi.org/10.1371/journal.pone.0243954.

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Light spectra of sunlight transmittance can generate an interactive effect with deposited nitrogen (N) on regenerated plants across varied shading conditions. Total N content in understory plants can be accounted for by both exogeneous and endogenous sources of derived N, but knowledge about the response of inner N cycling to interactive light and N input effects is unclear. We conducted a bioassay on Chinese cork oak (Quercus variabilis Blume) seedlings subjected to five-month N pulsing with 15NH4Cl (10.39 atom %) at 120 mg 15N plant-1 under the blue (48.5% blue, 33.7% green, and 17.8% red), red (14.6% blue, 71.7% red, 13.7% green), and green (17.4% blue, 26.2% red, 56.4% green) lighting-spectra. Half of the seedlings were fed twice a week using a 250 ppm N solution with micro-nutrients, while the other half just received distilled water. Two factors showed no interaction and neither affected growth and morphology. Compared to the red-light spectrum, that in blue light increased chlorophyll and soluble protein contents and glutamine synthetase (GS) activity, root N concentration, and N derived from the pulses. The green-light spectrum induced more biomass allocation to roots and a higher percentage of N derived from internal reserves compared to the red-light spectrum. The 15N pulses reduced the reliance on N remobilization from acorns but strengthened shoot biomass, chlorophyll content, GS activity, and N concentration. In conclusion, light spectrum imposed an independent force from external N pulse to modify the proportion of N derived from internal sources in total N content in juvenile Q. variabilis.

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Ardito Marretta, Rosario. „Digital control circuitry for the p53 dynamics in cancer cell and apoptosis“. Open Life Sciences 5, Nr. 2 (01.04.2010): 197–213. http://dx.doi.org/10.2478/s11535-009-0068-3.

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AbstractExperimental work and theoretical models deduce a “digital” response of the p53 transcription factor when genomic integrity is damaged. The mutual influence of p53 and its antagonist, the Mdm2 oncogene, is closed in a feedback. This paper proposes an aerospace-based architecture for translating the p53/Mdm2/DNA damage network into a digital circuitry in which the optimal control theory is applied for obtaining the requested dynamic evolutions of some considered cell species for repairing a DNA damage. The purpose of this paper is to demonstrate the usefulness of such digital circuitry design to detect and predict the cell species dynamics for shedding light on their inner and mutual mechanisms of interaction. Moreover, the cell fate is newly conceived by the modified pulsing mechanism of p53 and other apoptotic species when the digital optimal control is applied to an apoptosis wiring diagram.

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Lee, J. M., Nark-Eon Sung, Jeong-Kweon Park, Jah-Geol Yoon, Jin-Hong Kim, Man-Ho Choi und Ki-Bong Lee. „Design and feasibility of quick EXAFS scans for a `broomstick' double-crystal monochromator at PLS beamline“. Journal of Synchrotron Radiation 5, Nr. 3 (01.05.1998): 524–26. http://dx.doi.org/10.1107/s0909049598000831.

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A data-collection technique for quick extended X-ray absorption fine-structure spectroscopy (QEXAFS) was developed with a new `broomstick' double-crystal monochromator, which has been installed for X-ray absorption fine-structure (XAFS) applications at the Pohang Light Source. The monochromator operates in a fixed-exit scan mode as the Bragg angle is varied from 8 to 80°, corresponding to 2–14 keV, using an Si(111) crystal. The monochromator scan capability was investigated by analysing EXAFS data quality from step-scan and from continuous rotation of the Bragg crystal reflection angle. In our fast continuous-scan design, the electronic pulsing speed of the step motor is adjustable to avoid the monochromatic beam instability caused by serious mechanical resonance. The feasibility of QEXAFS scanning is demonstrated by a typical EXAFS scan (e.g. 1 keV range) being taken within 1 min.

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Chambers, Paul, Ed A. D. Austin, Mark J. Gunning und John P. Dakin. „Investigation of the peak power enhancement available from a surface emitting GaAlAs near-infrared light emitting diode by cooling and pulsing“. Measurement Science and Technology 14, Nr. 11 (26.09.2003): 2006–14. http://dx.doi.org/10.1088/0957-0233/14/11/020.

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Pietsch, W., W. Voges, E. Kendziorra und M. Pakull. „Exosat Observations of H2252−035: Pulse Phase and Orbital Phase Dependent Low Energy Absorption and Iron Line Emission“. International Astronomical Union Colloquium 93 (1987): 281–92. http://dx.doi.org/10.1017/s0252921100104993.

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AbstractThe 805 sec pulsing X-ray source H2252−035 has been observed for 7 h on September 14/15 and on September 17, 1983 in X-rays with the low energy telescope and the medium energy detectors of EXOSAT. While below 2 keV the semiamplitude of the 805 s pulses is ~ 100% in the 2.3–7.9 keV band it is only ~ 40%. X-ray dips that are more pronounced in low energies occur simultaneously with the orbital minimum of the optical light curve. The medium energy spectra during dips with respect to the non dip spectrum can be explained by just enhanced cold gas absorption of an additional absorbing column of 2 1022 cm−2. Model spectra for the 805 s minimum have to include a strong iron emission line at 6.55 keV with an equivalent width of 3 keV in addition to a reduced continuum intensity (radiating area) and enhanced low energy absorption.

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Marigo, Paola, Léo Girardi, Alessandro Bressan, Bernhard Aringer, Marco Gullieuszik, Enrico V. Held, Martin A. T. Groenewegen, Laura Silva und Gian Luigi Granato. „TP-AGB stars in population synthesis models“. Proceedings of the International Astronomical Union 5, S262 (August 2009): 36–43. http://dx.doi.org/10.1017/s1743921310002498.

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AbstractIn spite of its relevance, the Thermally Pulsing Asymptotic Giant Branch (TP-AGB) phase is one of the most uncertain phases of stellar evolution, and a major source of disagreement between the results of different population synthesis models of galaxies. I will briefly review the existing literature on the subject, and recall the basic prescriptions that have been used to fix the contribution of TP-AGB stars to the integrated light of stellar populations. The simplicity of these prescriptions greatly contrasts with the richness of details provided by present-day databases of AGB stars in the Magellanic Clouds, which are now being extended to other nearby galaxies. I will present the first results of an ongoing study aimed at simulating photometry, chemistry, pulsation, mass loss, dust properties of AGB star populations in resolved and un-resolved galaxies. We test our predictions against observations from various surveys of the Magellanic Clouds (DENIS, 2MASS, OGLE, MACHO, Spitzer, and AKARI). I will discuss the implications and outline the plan of future developments.

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Chilicka, Karolina. „Estimation of selected skin parameters during a series of beauty treatments in women with acne: a pilot study“. Medical Science Pulse 15, Nr. 1 (12.05.2021): 1–10. http://dx.doi.org/10.5604/01.3001.0014.8697.

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Background: Acne vulgaris occurs most often in young people and can significantly decrease the quality of life. Properly selected dermatological therapy and cosmetic procedures can effectively improve the skin condition of acne patients. Aim of the study: The aim of this study was to examine how various cosmetics treatments affect facial sebum levels, skin hydration, and desquamation in young women with acne vulgaris. Material and Methods: 101 women with acne aged 19–29 (M = 22.5 years, SD = 2.3 years) were included in the study. The following cosmetic treatments were used over a 12-week period: intensive pulsing light, alpha-hydroxy acids, cavitation peeling, non-needle mesotherapy, diamond microdermabrasion, and sonophoresis. Skin parameters, including oily skin level, desquamation level, and moisture level were analyzed twice (at baseline and after 12 weeks) using a Nati skin analyzer. Results: The series of cosmetic procedures significantly improved skin lubrication (p<0.0001), hydration in the T zone (p<0.0001), and desquamation (p< 0.0001). Conclusions: The use of modern cosmetic devices in the beauty studio can be very effective for the treatment of acne lesions.

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Shortall, Adrian C., Mohammed A. Hadis und William M. Palin. „On the inaccuracies of dental radiometers“. PLOS ONE 16, Nr. 1 (29.01.2021): e0245830. http://dx.doi.org/10.1371/journal.pone.0245830.

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This study investigated the accuracy of sixteen models of commercial dental radiometers (DR) in measuring the output of thirty-eight LED light curing units (LCUs) compared with a 'gold standard' laboratory-grade spectrometer integrating-sphere (IS) assembly. Nineteen Type I (fiber-bundle light guide) and nineteen Type II (light source in head) LED LCUs were tested, some using different output modes and light guides, resulting in 61 test subsets per radiometer. Gold standard (GS) output measurements (n = 3) were taken using the IS and confirmed with two types of laboratory-grade power meter (PowerMax-Pro 150 HD and PM10-19C; Coherent). One DR (Bluephase Meter II, Ivoclar; BM II) allowed power (mW) as well as irradiance (mW/cm2) recordings. Irradiance readings (n = 3) for each DR/LCU were compared with the IS derived irradiance. Individual LCU irradiance values were normalized against IS data. The GS method yielded reproducible data with a 0.4% pooled coefficient of variation for the LCUs. Mean power values ranged from 0.19 W to 2.40 W. Overall power values for the laboratory-grade power meters were within 5% of GS values. Individual LCU/DR normalized irradiance values ranged from 7% to 535% of the GS; an order of magnitude greater than previous reports. BM II was the only radiometer to average within 20% of normalized pooled GS irradiance values, whereas other radiometers differed by up to 85%. Ten radiometers failed to provide any reading for 1 LCU. When tested with the PowerMax-Pro in high speed (20 kHz) mode, eight LCUs demonstrated pulsing outputs undetectable at the standard (10 Hz) data acquisition rate. Sufficient light exposure is critical for the successful curing of dental resin-based materials. Substantial discrepancies may occur between actual and estimated radiometric data using current DRs. More accurate DRs need to be developed. Manufacturers' accuracy claims for DRs should specify compatible LCUs and testing parameters.

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Xie, Sheng, Junting Liu und Fan Zhang. „An Accurate Circuit Model for the Statistical Behavior of InP/InGaAs SPAD“. Electronics 9, Nr. 12 (03.12.2020): 2059. http://dx.doi.org/10.3390/electronics9122059.

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In the field of near-infrared weak light detection, an InP/InGaAs single-photon avalanche diode (SPAD) is preferred due to the advantages of high sensitivity, low cost and room-temperature operation. To properly simulate and optimize the SPAD’s front-end circuit, a comprehensive and compact behavior model of the InP/InGaAs SPAD is normally required to accurately describe the statistical behavior of the detectors. In this paper, an InP/InGaAs SPAD analytical model is constructed, which not only includes the direct current (DC) and alternating current (AC) behavior simulating the avalanche and quenching processes, but also describes the dark count, after-pulsing and photon detection efficiency. For dark count noise, three important generation mechanisms are considered, including thermal generation, trap-assisted tunneling and band-to-band tunneling. The model described by the Verilog-A hardware description language (HDL) can be directly implemented in the commercial circuit simulator. A gated mode, passive quenching and recharging circuit is used to simulate and verify the developed model. The simulation results are in good agreement with the reported test data, demonstrating the accuracy of the developed InP/InGaAs SPAD model.

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Uetrecht, Charlotte, Kristina Lorenzen, Matthäus Kitel, Johannes Heidemann, Jesse Huron Robinson Spencer, Hartmut Schlüter und Joachim Schulz. „Native mass spectrometry provides sufficient ion flux for XFEL single-particle imaging“. Journal of Synchrotron Radiation 26, Nr. 3 (11.04.2019): 653–59. http://dx.doi.org/10.1107/s1600577519002686.

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The SPB/SFX instrument at the European XFEL provides unique conditions for single-particle imaging (SPI) experiments due to its high brilliance, nano-focus and unique pulse structure. Promising initial results provided by the international LCLS (Linac Coherent Light Source) SPI initiative highlight the potential of SPI. Current available injection methods generally have high sample consumption and do not provide any options for pulsing, selection or orientation of particles, which poses a problem for data evaluation. Aerosol-injector-based sample delivery is the current method of choice for SPI experiments, although, to a lesser extent, electrospray and electrospinning are used. Single particles scatter only a limited number of photons providing a single orientation for data evaluation, hence large datasets are required from particles in multiple orientations in order to reconstruct a structure. Here, a feasibility study demonstrates that nano-electrospray ionization, usually employed in biomolecular mass spectrometry, provides enough ion flux for SPI experiments. A novel instrument setup at the SPB/SFX instrument is proposed, which has the benefit of extremely low background while delivering mass over charge and conformation-selected ions for SPI.

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Khalimova, L. I. „Evaluating the Effectiveness of Accelerated and Accelerated Cornea Pulsing Crosslinking Based on the Presence of a Demarcation Line“. Ophthalmology in Russia 16, Nr. 1S (22.04.2019): 127–31. http://dx.doi.org/10.18008/1816-5095-2019-1s-127-131.

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Purpose of the study is to assess the state of the demarcation line of the stroma after accelerated and pulsed accelerated ultraviolet cornea crosslinking. Patients and methods. Clinical observations included 24 patients (31 eyes) with keratoconus (KC), aged 18–46 years, men — 11 (45.9 %), women — 13 (54.1 %). Accelerated (a-CXL) crosslinking was carried out in continuous mode with a power of 18 mW/cm2 for 5 minutes (13 eyes), pulsed accelerated (i-ACXL) with a power of 18 mW/cm2 for 10 minutes, in mode 1 sec light / 1 sec pause (18 eyes). Conducted generally accepted and additional methods of ophthalmic research. The follow-up periods were 1, 3, and 6 months after surgery. Results. According to optical coherent tomography, the demarcation line was detected in all cases after a-CXL and i-ACXL. At 1 month after the crosslinking, there were no significant differences between the a-CXL and i-ACXL groups in terms of uncorrected visual acuity, corrected visual acuity, maximal correction. The average depth with demarcation at 1 month after the procedure in the central zone of the cornea was 216.41 ± 36.67 μm in the a-CXL group and 236.41 ± 37.08 μm in the i-ACXL group. Using confocal microscopy in vivo in both groups 1 month after surgery apoptosis of keratocytes and stromal edema were detected. A gradual restoration of the cornea to its original state was observed after 6 months. Conclusion. Research results have shown that accelerated and pulsed accelerated cross-linking are safe and effective technologies to stabilize the progression of keratoconus. Both crosslinking protocols provide a significant reduction in the duration of the procedure compared to the traditional one. Revealed deeper arrangement of the demarcation line when performing pulsed accelerated crosslinking compared to the accelerated. Further long-term and more extensive studies of accelerated and pulsed accelerated cornea ultraviolet crosslinking will provide improved information on their effectiveness in the long-term.

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Hayes, J. C., M. Garvey, A. M. Fogarty, E. Clifford und N. J. Rowan. „Inactivation of recalcitrant protozoan oocysts and bacterial endospores in drinking water using high-intensity pulsed UV light irradiation“. Water Supply 12, Nr. 4 (01.07.2012): 513–22. http://dx.doi.org/10.2166/ws.2012.017.

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This constitutes the first study to compare the use of high-intensity pulsed UV light (PUV) irradiation for the novel destruction of harmful protozoan (Cryptosporidium parvum Iowa isolate) oocysts and bacterial (Clostridium perfringens ATCC 13124 and Bacillus cereus ATCC 11178) endospores in artificially-spiked water where these organisms are resistant to conventional chlorination. Experimental results revealed that all three test organisms in their dormant recalcitrant state required extended levels of pulsing to achieve significant reductions in numbers compared to other similarly PUV-treated Escherichia coli ATCC 25922 that is a non-spore forming indicator of faecal pollution in water. 120 pulses at 900 V or 16.2 J per pulse (equivalent to a UV dose of 8.39 μJ cm−2) were required to achieve ca. 2 log C. perfringens spore numbers, whereas a similar level of PUV irradiation reduced both C. parvum oocysts and B. cereus endospores by ca. 5 log orders. A comparative ca. 5 log reduction of E. coli cell numbers was achieved after only 25 pulses at 900 V (equivalent to a UV dose of 1.74 μJ cm−2). A clear trend emerged where the order of resistance to PUV-irradiation observed was C. perfringens endospores > C. parvum oocysts, B. cereus endospores > E. coli cells. This study suggests disinfection kinetic data for the more resistant C. perfringens endospores can be used as a measure of estimating disinfection efficacy of PUV treatments for C. parvum oocysts in water, avoiding the need to use complex animal or cell culture infectivity models that are only available in specialised laboratories with highly trained technicians. This study will inform future studies exploring scale-up of PUV at waste-water treatment plants.

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Journal, Baghdad Science. „Laser Effect on Fatique Resistance of Carbon Steel“. Baghdad Science Journal 8, Nr. 1 (06.03.2011): 44–47. http://dx.doi.org/10.21123/bsj.8.1.44-47.

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Laser beam has been widely used to improve the mechanical properties of the metals. It used for cutting, drilling, hardening, welding……etc. The use of Laser beam has many features in accuracy and speeding in work, also in the treatment of metals locally, and in the places that is hard to reach by traditional ways. In this research a surface treatment was done to medium carbon steel (0.4%C) which is common kind of steel that is used in industry. Pulsing Neodymium -YAG Laser has been used and 1.06 micrometer wave length and 5 msec and the distance is about 30 centimeter between the exit area of the Laser beam from the system and the piece that treated . We are going to check the fatigue resistance for samples that is treated by Laser beam and Scanning Electron Microscope (SEM) and also we made check for the microstructure by using the light microscope and the SEM for the breaking samples. The results of checking showed that there is an improvement in the fatigue resistance after the treatment by the Laser beam. The results of microscope checking showed that the beginning of the failure is from the surface area and there is more than one level of the break.

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Heil, M., A. Juseviciute, F. Käppeler, R. Gallino, M. Pignatari und E. Uberseder. „Neutron Capture Cross Sections for the Weak s Process“. Publications of the Astronomical Society of Australia 26, Nr. 3 (2009): 243–49. http://dx.doi.org/10.1071/as08064.

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AbstractIn past decades a lot of progress has been made towards understanding the main s-process component that takes place in thermally pulsing Asymptotic Giant Branch (AGB) stars. During this process about half of the heavy elements, mainly between 90 ≤ A ≤ 209 are synthesized. Improvements were made in stellar modeling as well as in measuring relevant nuclear data for a better description of the main s process. The weak s process, which contributes to the production of lighter nuclei in the mass range 56 ≤ A ≤ 90 operates in massive stars (M ≥ 8 M⊙) and is much less understood. A better characterization of the weak s component would help disentangle the various contributions to element production in this region. For this purpose, a series of measurements of neutron-capture cross sections have been performed on medium-mass nuclei at the 3.7-MV Van de Graaff accelerator at FZK using the activation method. Also, neutron captures on abundant light elements with A < 56 play an important role for s-process nucleosynthesis, since they act as neutron poisons and affect the stellar neutron balance. New results are presented for the (n, γ) cross sections of 41K and 45Sc, and revisions are reported for a number of cross sections based on improved spectroscopic information.

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Mickaliger, Mitchell B., Ben W. Stappers, Cees G. Bassa und Aldus G. Fletcher. „1,000,000 Giant Pulses from the Crab Pulsar“. Proceedings of the International Astronomical Union 13, S337 (September 2017): 380–81. http://dx.doi.org/10.1017/s174392131700922x.

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AbstractThe Crab pulsar was first detected soon after the discovery of pulsars, and has long been studied for its unique traits. One of these traits, giant pulses that can be upwards of 1000 times brighter than the average pulse, was key to the Crab’s initial detection. Giant pulses are only seen in a few pulsars, and their energy distributions distinguish them from normal pulsed emission. There have been many studies over a period of decades to measure the power-law slope of these energy distributions, which provide insight into the possible emission mechanism of these giant pulses.The 42-foot telescope at Jodrell Bank Observatory monitors the Crab pulsar on a daily basis. We have single-pulse data dating back to 2012, containing roughly 1,000,000 giant pulses, the largest sample of Crab giant pulses to date. This large set of giant pulses allows us to do a range of science, including pulse-width studies and in-depth studies of giant-pulse energy distributions. The latter are particularly interesting, as close inspection of the high-energy tail of the energy distribution allows us to investigate the detectability of extragalactic giant-pulsing pulsars. Also, by calculating rates from these energy distributions, we may be able to shed light on a possible link between Fast Radio Bursts and giant pulses.

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Böttrich, Marcel, Daniel Laqua und Peter Husar. „Principle study on the signal connection at transabdominal fetal pulse oximetry“. Current Directions in Biomedical Engineering 2, Nr. 1 (01.09.2016): 659–63. http://dx.doi.org/10.1515/cdbme-2016-0144.

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AbstractTransabdominal fetal pulse oximetry is an approach to measure oxygen saturation of the unborn child non-invasively. The principle of pulse oximetry is applied to the abdomen of a pregnant woman, such that the measured signal includes both, the maternal and the fetal pulse curve. One of the major challenges is to extract the shape of the fetal pulse curve from the mixed signal for computation of the oxygen saturation. In this paper we analyze the principle kind of connection of the fetal and maternal pulse curves in the measured signal. A time varying finite element model is used to rebuild the basic measurement environment, including a bulk tissue and two independently pulsing arteries to model the fetal and maternal blood circuit. The distribution of the light fluence rate in the model is computed by applying diffusion equation. From the detectors we extracted the time dependent fluence rate and analyzed the signal regarding its components. The frequency spectra of the signals show peaks at the fetal and maternal basic frequencies. Additional signal components are visible in the spectra, indicating multiplicative coupling of the fetal and maternal pulse curves. We conclude that the underlying signal model of algorithms for robust extraction of the shape of the fetal pulse curve, have to consider additive and multiplicative signal coupling.

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Challinger, Susanna E., Iain D. Baikie, Jonathon R. Harwell, Graham A. Turnbull und Ifor D. W. Samuel. „An Investigation of the Energy Levels within a Common Perovskite Solar Cell Device and a Comparison of DC/AC Surface Photovoltage Spectroscopy Kelvin Probe Measurements of Different MAPBI3 Perovskite Solar Cell Device Structures“. MRS Advances 2, Nr. 21-22 (2017): 1195–201. http://dx.doi.org/10.1557/adv.2017.72.

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ABSTRACTWe present a study of the energy levels in a FTO/TiO2/CH3NH3PbI3/Spiro solar cell device. The measurements are performed using a novel ambient pressure photoemission (APS) technique alongside Contact Potential Difference data from a Kelvin Probe. The Perovskite Solar Cell energy band diagram is demonstrated for the device in dark conditions and under illumination from a 150W Quartz Tungsten Halogen lamp. This approach provides useful information on the interaction between the different materials in this solar cell device. Additionally, non-destructive macroscopic DC and AC Surface Photovoltage Spectroscopy (SPS) studies are demonstrated of different MAPBI3 device structures to give an indication of overall device performance. AC-SPS measurements, previously used on traditional semiconductors to study the mobility, are used in this case to characterise the ability of a perovskite solar cell device to respond rapidly to chopped light. Two different device structures studied showed very different characteristics: Sample A (without TiO2): (ITO/PEDOT:PSS/polyTPD/CH3NH3PbI3/PCBM) had ∼4 times the magnitude of AC-SPS response compared to Sample B (including TiO2): (ITO/TiO2/ CH3NH3PbI3/Spiro). This demonstrates that the carrier speed characteristics of device architecture A is superior to device architecture B. The TiO2 layer has been associated with carrier trapping which is illustrated in this example. However, the DC-SPV performance of sample B is ∼5 times greater than that of sample A. The band gap of the MAPBI3 layer was determined through DC-SPS (1.57 ± 0.07 eV), Voc of the devices measured and qualitative observations made of interface trapping by DC light pulsing. The combination of these (APS, KP, AC/DC-SPV/SPS) techniques offers a more general method for measuring the energy level alignments and performance of Organic and Hybrid Solar Cell Devices.

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Iwamoto, Nobuyuki. „Evolution and Nucleosynthesis in Extremely Metal-Poor, Asymptotic Giant Branch Stars“. Publications of the Astronomical Society of Australia 26, Nr. 3 (2009): 145–52. http://dx.doi.org/10.1071/as08036.

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AbstractWe evolve extremely metal-poor ([Fe/H]≃–3), thermally pulsing Asymptotic Giant Branch (AGB) models with the mass range of 1–8 M⊙. The chemical yields ejected from the models are obtained by considering mass loss. We find that the 1- and 2-M⊙ AGB models are not affected by hot bottom burning (HBB). Nevertheless, they produce large amount of 7Li in an H-flash event. The occurrence of this event is associated with the ingestion of protons from the overlying H-rich envelope into the He convective shell driven by thermal pulse. The resulting 7Li abundances in the ejecta are higher than the primordial one predicted in Big-Bang nucleosynthesis. The efficient production of 7Li by the operation of HBB is also confirmed in the models of 4–8 M⊙. If these AGB stars have a low-mass companion, it is probable that mass loss from the primary AGB star brings the materials enriched in 7Li into the secondary star. This makes the surface composition of the secondary Li-rich. The formation of Li-rich stars, however, is strongly dependent on the mass loss history and binary separation. The nucleosynthesis for the other light nuclei is also calculated up to the end of the AGB phase. We find that the abundance patterns of the metal-poor stars CS 29528–041 and CS 29497–030 are well reproduced by yields from our AGB models.

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Kolodii, A. A., E. A. Shatokhina und R. I. Khalilullin. „Review of modern physiotherapeutic methods in treatment of acne“. Medical alphabet 1, Nr. 7 (05.03.2019): 15–18. http://dx.doi.org/10.33667/2078-5631-2019-1-7(382)-15-18.

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The article presents modern views on the pathogenesis of acne, as well as the analysis of the literature data on physiotherapy methods of treatment. Acne is the most common inflammatory chronic recurrent skin disease caused by changes in pilosebatsionnyh structures. Acne of varying severity affects 80-85 % of people in the age of 12-25 years and 11 % over the age of 25 years. This pathology has a wide range of clinical manifestations: patients have open and closed comedones, as well as inflammatory skin lesions, including papules, pustules and nodes. in modern literature, it is common to distinguish 4 main factors of acne development: pathological vulgar hyperkeratosis, increased secretion of the sebaceous glands, Propionibacterium acne activity, local inflammation. Correction of these four pathogenic factors is the aim of physiotherapeutic methods of acne treatment. Currently, the most popular are the following methods: Photodynamic therapy: this method is aimed to destruct P. Acne and sebaceous glands. The mechanism of action is based on the selective destruction of cells as a result of light - activated chemical reaction in the presence of a substance - photosensitizer. IPL (Intense Pulsed Light) therapy is a technique based on the use of a special intense pulsing light. The skin surface is exposed to incoherent pulses of visible light with a wavelength of 500-1 200 nm. it is believed that these impulses penetrate deeply into the follicle and photoactivating the porflrins of the microorganism and causing its death. Microcurrent therapy is a method of impact on the human body with the help of modulated pulse currents of low power (up to 1 mA) with minimum voltage and different frequency used for therapeutic or cosmetic effect. it is believed that the impact of low voltage currents has a positive effect on cell metabolism, increases the synthesis of adenosine triphosphate. The procedure, activates fibroblasts, improves microcirculation, normalizes the sebaceous glands and pore reduction. Also in the treatment of acne and post-acne are widely used two types of lasers: ablative type - provides a directed damage to the affected skin, including the epidermis, while laser radiation is approximately equally absorbed by all layers of the skin; non-ablative type - as a result of the radiation by this type of laser, there is a selective removal of pathological structures without damage of the epidermis. Radiation is selectively absorbed by these structures, but not by the epidermis. Reasonable combined administration of systemic and topical drugs in the combination with physiotherapeutic methods, allows to achieve a good clinical effect and improve the quality of life of patients with various forms of acne.

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Garugubilli, Ramu, M. L. Sramika und V. Pradeep Kumar. „An Experimental Study on Mechanical Behaviour of Pulsed Current Welding on Aluminum Alloy Joints“. Advanced Materials Research 1148 (Juni 2018): 193–203. http://dx.doi.org/10.4028/www.scientific.net/amr.1148.193.

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Aluminum alloys (Al–Si–Mg alloys) have gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders. An improvised method is Pulsed current tungsten inert gas (PCTIG) welding (Developed in 1950s). The pulse current is more frequently used in manual welding because it has a lot of advantages in comparison to direct current. The main advantages are improved bead contour, greater tolerance to heat sink variations, lower heat input requirements, reduced residual stresses and distortion. In the present work to study the effect of PCTIG welding over continuous current TIG welding, work plates of 6 mm thickness have been used as the base material for preparing single pass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al–5Mg (wt%)) grade aluminum alloy The preferred welding processes of moderately high strength aluminum alloy are frequently tungsten inert gas welding (TIGW) process. Two different welding techniques are used to fabricate the joints and they are: (i) continuous current TIG welding (CCGTAW) (ii) pulse current TIG welding (PCGTAW) processes. Argon (99.99% pure) has to use as the shielding gas. This report presents the effect of pulsed current TIG welding on mechanical behavior of high strength aluminum alloy joints, and studying about the grain refinement of weld bead, conducting the mechanical tests such as tensile test, impact test, and hardness test. Pulsed current welded joints have given superior mechanical properties comparative to continue current welded joints. PCTIG welded joints given high tensile strength, hardness and impact strength values. Current pulsing leads to relatively finer structure.

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HOLDER, D. A., A. V. SMITH, C. J. BARTON und D. L. YOUNGS. „Shock-tube experiments on Richtmyer–Meshkov instability growth using an enlarged double-bump perturbation“. Laser and Particle Beams 21, Nr. 3 (Juli 2003): 411–18. http://dx.doi.org/10.1017/s0263034603213197.

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This article reports on the latest experiments in the series of Richtmyer–Meshkov instability (RMI) shock-tube experiments. Previous work described a double-bump experiment that evidenced some degree of unrepeatability. The present work features an enlarged perturbation introduced to improve repeatability. In common with the previous work, the experiments were conducted at shock Mach number 1.26 (70 kPa overpressure), using the Atomic Weapons Establishment 200 × 100 mm shock tube with a three-zone test cell arrangement of air/sulphur hexafluoride/air. The sulphur hexafluoride gas (SF6) was chosen for its high density (5.1 relative to air) providing an Atwood number of 0.67. Gas separation was by means of microfilm membranes, supported by fine wire meshes. A double-bump perturbation of two-dimensional geometry was superimposed on the downstream membrane representing a 0.6% addition to the dense gas volume. Visualization of the turbulent gas mixing was by laser sheet illumination of the seeded SF6gas using a copper vapor laser pulsing at 12.5 kHz. Mie scattered light was recorded using a 35-mm rotating drum camera to capture a sequence of 50 images per experiment. Sample experimental results shown alongside corresponding three-dimensional hydrocode calculations highlight the problems in both analysis and comparison caused by multiple scattering arising from the necessary use of a high seeding concentration. Included is a demonstration of the effectiveness of introducing into the hydrocode a Monte Carlo-based simulation of the multiple scattering process. The results so derived yield greatly improved qualitative agreement with the experimental images. Quantitative analysis took the form of deriving relative intensity data from line-outs through experimental images and their code equivalents. A comparison revealed substantial agreement on major features.

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Williams, Michael D., Ron Van Houten, John Ferraro und Bruce B. Blasch. „Field Comparison of Two Types of Accessible Pedestrian Signals“. Transportation Research Record: Journal of the Transportation Research Board 1939, Nr. 1 (Januar 2005): 91–98. http://dx.doi.org/10.1177/0361198105193900111.

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The effects of two types of accessible pedestrian signals on the street-crossing behaviors of 24 totally blind participants were directly compared in this research. One accessible pedestrian signal (APS) used a sound generator and vibrating hardware, which were integrated into the pedestrian push button (the Polara device). These sounds were heard from the near vicinity of the push button, and a different message or repetition rate was used to indicate the “Walk” interval. The second APS used pulsing light-emitting diodes to illuminate the message in the pedestrian signal head to transmit a message to a handheld receiver carried by the blind traveler (the Relume device). The handheld receiver provided a “Walk” or “Wait” message, designated by variable tones, which was audible only to the user. A control condition consisted of crossing without any APS device. Data were collected on crossing speed, the latency from the start of the walk and entering the crosswalk, the number of cycles missed, and the accuracy of the crossing. The results indicated that the time to cross the street was significantly shorter when participants used the handheld device than when they used the audible push-button device or crossed without any APS. There was no significant difference in crossing times between participants who used the audible push-button device and those who crossed without an APS under the control condition. The latency to start crossing was significantly faster when the participants used the handheld device than when they used the audible push button or crossed without an APS under the control condition. The number of missed cycles was significantly lower when the participant used either APS device than when the participant crossed without an APS device, and there was no difference in the number of missed cycles between the two APS devices.

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Hollowell, David, und Icko Iben. „Nucleosynthesis and Mixing in Low- and Intermediate-Mass AGB Stars“. International Astronomical Union Colloquium 108 (1988): 38–43. http://dx.doi.org/10.1017/s0252921100093374.

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AbstractThe existence of carbon stars brighter than Mbol=-4 can be understood in terms of dredge up in thermally pulsing asymptotic giant branch (AGB) stars. As a low- or intermediate-mass star evolves on the AGB, the large fluxes engendered in a helium shell flash cause the base of the convective envelope to extend into the radiative, carbon-rich region, and transport nucleosynthesis products to the stellar surface. Numerical models indicate that AGB stars with sufficiently massive stellar envelopes can become carbon stars via this standard dredge-up mechanism. AGB stars with less massive stellar envelopes can become carbon stars when carbon recombines in the cool, carbon-rich region below the convective envelope.Neutron capture occurs on iron-seed nuclei during a shell flash, and the products of this nucleosynthesis are also carried to the stellar surface. The conversion of 22Ne into 25Mg can initiate neutron capture nucleosynthesis in largecore mass AGB stars, but only if these stars can survive their large mass loss rates. The current estimates of nuclear reaction rates do not allow for appreciable neutron capture nucleosynthesis via the 22Ne source in lower mass AGB stars. The carbon recombination that induces dredge up in AGB stars of small envelope mass, however, also induces mixing of 1H and 12C in such a way that ultimately a 13C neutron source is activated in these stars. The 13C source can provide an abundant supply of neutrons for the nucleosynthesis of both light and heavy elements. While the existence of neutron-nucleosynthesis products in AGB stellar atmospheres can be understood qualitatively in terms of an active neutron source, the combination of nuclear reaction theory and evolutionary models has yet to provide quantitative agreement with stellar observations.

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Du, Xin-Ru, und Ling-Xiu Zhao. „ANATOMIC AND CLINICAL STUDY OF A NEUROVASCULAR CAUSE OF LATERAL EPICONDYLITIS“. Journal of Musculoskeletal Research 12, Nr. 01 (März 2009): 11–19. http://dx.doi.org/10.1142/s0218957709002171.

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Because of few anatomic reports investigating the mechanism of lateral epicondylitis (tennis elbow), we performed cadaveric and clinical studies to investigate the involvement of neurovascular bundles passing through the common extensor origin. We dissected and observed under a light microscope tissue samples of neurovascular bundles passing through the common extensor tendon from 40 upper left and right limbs from cadavers. Tissue samples were prepared by hematoxylin & eosin and Weil's myelin staining. We also investigated the records of 20 patients who had been treated for lateral epicondylitis between 1991 and 2004. From cadavers, we found 60 bundles in the common extensor tendon, each 0.5 to 1.0 mm in diameter, with more bundles in the right than left limbs. Twenty-four of these bundles passed over the vertex of the lateral epicondyle of the humerus, and most of the bundles contained only one artery each. The bundles mostly originated from the radial recurrent artery, passing through the aponeurosis of the extensor corpi radialis brevis, but in some cases originated from the radial collateral artery, passing through the aponeurosis of the triceps brachii muscle. The bundles had a membranous covering when passing through the aponeurosis and produced a hiatus. Histological analysis of resected common extensor tendon tissue, 1 cm in diameter, of patients showed hyaline degeneration and fibrosis formation infiltration. Neurovascular bundles passed through the common extensor tendon in nine cases; six cases showed pulsing bleeding. After a mean follow-up of two years (6–48 months), 16 cases showed excellent results, two showed good results and two showed reliefs. Lateral epicondylitis could be caused by damage to neurovascular bundles when they pass through the common extensor origin; one cause of pain is the neurovascular bundle being compressed when passing through the common extensor tendon, secondary to the pathologic degeneration of the origin of the common extensor tendon.

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Novikova, M. F., und Yu A. Fadeyev. „Statistics of Pulsating Variables“. International Astronomical Union Colloquium 111 (1989): 280. http://dx.doi.org/10.1017/s025292110001188x.

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AbstractClassification of pulsating variables is based on a number of properties but the most important of them are the period and amplitude of the light variation. These quantities also play an important role in understanding the evolutionary status of the pulsating stars since the pulsation period is related to the mass and radius through the period--mean density relation while the amplitude of the light curve characterizes the efficiency of the mechanism responsible for the pulsational instability. In the present study we considered the period--frequency and light amplitude--frequency distributions for ten types of the most numerous pulsating variables from the fourth edition of the General Catalogue of Variable Stars. The following types of pulsating variables were considered: DSCT, DSCTC, DCEP, RR, RRAB, RRC, CWA, CWB, RV and M. Using these distributions we estimated the upper and lower limits of the period and light amplitude within which 95% and 99% of the pulsating stars of a given type are contained.

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CASTANHEIRA, BÁRBARA GARCIA, und S. O. KEPLER. „THE PULSATING WHITE DWARF G 185-32“. International Journal of Modern Physics D 13, Nr. 07 (August 2004): 1213–16. http://dx.doi.org/10.1142/s021827180400533x.

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We study the structure of pulsating white dwarf stars, which present multi-periodic light variations with periods around minutes, defining instability strips along their cooling sequence. We analyze the ultraviolet (HST) and optical (WET) light curves of the pulsating white dwarf G185-32. Among all pulsating white dwarfs, this star has the shortest periodicity so far observed. We detected 18 periodicities, including non-linear effects, which can be used to study the stellar structure, constraining the physics of the degenerate matter.

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Feuchtinger, Michael U., und Ernst A. Dorfi. „Theoretical UBVI Light Curves of Pulsating Stars“. International Astronomical Union Colloquium 176 (2000): 334–37. http://dx.doi.org/10.1017/s0252921100058012.

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AbstractBy performing detailed frequency-dependent radiative transfer computations we are able to calculate light curves in particular bandpasses from stellar pulsation models calculated by the Vienna nonlinear convective pulsation code. As a sample application we discuss UBVI light curves of RR Lyrae stars. The properties of these light curves are analyzed by means of standard Fourier decomposition, and a comparison to recent observations is performed. As main results we find a good agreement with important observed RR Lyrae properties like pulsation amplitudes and Fourier parameters in B, V, and I bands. Additionally, from the synthetic color curves we derive linear transformation laws between amplitudes as well as Fourier parameters in the different bandpasses.

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50

Serre, T. „Predicting Variable Star Light Curves“. International Astronomical Union Colloquium 134 (1993): 145–47. http://dx.doi.org/10.1017/s0252921100014056.

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AbstractI present a new method to test determinism, in particular the nonlinear behavior, in observed time series of pulsating stars, based on a recent prediction method which exploits the dynamical system theory. A method for filling gaps in data has thereby been constructed. Estimated bounds to the necessary embedding dimension can be obtained and chaotic divergences can be estimated.

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