The gamma-ray observation of dwarf spheroidal satellites (dSph's) is an ideal approach for probing the dark matter (DM) annihilation signature. The latest Fermi-LAT dSph searches have set stringent ...constraints on the velocity independent annihilation cross section in the small DM mass range, which gives very strong constraints on the scenario to explain the AMS-02 positron excess by DM annihilation. However, the dSph constraints would change in the velocity dependent annihilation scenarios, because the velocity dispersion in the dSph's varies from that in the Milky Way. In this work, we use a likelihood map method to set constraints on the velocity dependent annihilation cross section from the Fermi-LAT observation of six dSph's. We consider three typical forms of the annihilation cross section, i.e. p-wave annihilation, Sommerfeld enhancement, and Breit-Wigner resonance. For the p-wave annihilation and Sommerfeld enhancement, the dSph limits would become much weaker and stronger compared with those for the velocity independent annihilation, respectively. For the Breit-Wigner annihilation, the dSph limits would vary depending on the model parameters. We show that the scenario to explain the AMS-02 positron excess by DM annihilation is still viable in the velocity dependent cases.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Information on the ambient aerosol number size distribution is essential to address various scientific questions related to aerosol particles in the atmosphere. However, due to the wide size and ...concentrations ranges of ambient aerosol particles, no single instrument alone is capable of measuring them all. Instruments based on different measurement principles are engaged in the measurement of atmospheric aerosols. Intercomparison of such instruments is necessary to cross-validate the reliability of obtained data. In this study, a verification of a Novosibirsk Aerosol Diffusion Spectrometer (ADS) in the size classification of aerosol particles was carried out in laboratory and via a field intercomparison with a Differential Mobility Particle Sizer (DMPS) and a Neutral cluster and Air Ion Spectrometer (NAIS). The laboratory experiments affirmed the good accuracy of the ADS on sizing and concentration measurement. The ADS was satisfactorily comparable with the DMPS and the NAIS for the measurement of ambient aerosols within the size range 3–200nm. The differences between condensation sinks derived from the ADS and DMPS measurements were smaller on days with new particle formation (NPF) than on non-NPF days. Similar formation rates and growth rates were acquired based on the DMPS, NAIS and ADS measurements, proving a reasonable ability of the ADS in measuring the concentrations and size distribution of nucleation-mode particles.
•We performed laboratory verification and field study with Novosibirsk Aerosol Diffusion Spectrometer (ADS).•For the concentration range of 103–105cm−3, there was a ±15% uncertainty in the number concentration by the ADS.•The particle sizing of the ADS was 10% of the specifications of the polystyrene latex spheres.•The ADS performed well during the field campaign in the aerosol size range from 3 to 200nm.•The ADS derived parameters for new particle formation showed a good agreement with other instruments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
493.
Light-Curing Units Price, R B; Ferracane, J L; Shortall, A C
Journal of dental research,
09/2015, Volume:
94, Issue:
9
Journal Article
Peer reviewed
For improved interstudy reproducibility, reduced risk of premature failures, and ultimately better patient care, researchers and dentists need to know how to accurately characterize the ...electromagnetic radiation (light) they are delivering to the resins they are using. The output from a light-curing unit (LCU) is commonly characterized by its irradiance. If this value is measured at the light tip, it describes the radiant exitance from the surface of the light tip, and not the irradiance received by the specimen. The value quoted also reflects only an averaged value over the total measurement area and does not represent the irradiance that the resin specimen is receiving locally or at a different moment in time. Recent evidence has reported that the spectral emission and radiant exitance beam profiles from LCUs can be highly inhomogeneous. This can cause nonuniform temperature changes and uneven photopolymerization within the resin restoration. The spectral radiant power can be very different between different brands of LCUs, and the use of irradiance values derived from dental radiometers to describe the output from an LCU for research purposes is discouraged. Manufacturers should provide more information about the light output from the LCU and the absorption spectrum of their resin-based composite (RBC). Ideally, future assessments and research publications should include the following information about the curing light: 1) radiant power output throughout the exposure cycle and the spectral radiant power as a function of wavelength, 2) analysis of the light beam profile and spectral emission across the light beam, and 3) measurement and reporting of the light the RBC specimen received as well as the output measured at the light tip.
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CMK, NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Natural products has been used for the prevention and treatment of diseases for a long history. Research on the bioactive components from natural products and their interaction with target proteins ...are essential for drug discovery. However, studying the binding ability of natural products' active ingredients to target proteins is usually time-consuming and laborious due to their complex and diverse chemical structures. In this study, we have developed a high resolution micro-confocal Raman spectrometer-based photo-affinity microarray (HRMR-PM) technology for the investigation of active ingredients-target protein recognition strategy. The novel photo-affinity microarray was constructed by photo-cross-linking the small molecule with the photo-affinity group (4-3-(Trifluoromethyl)-3H-diazirin-3-ylbenzoic acid, TAD) on the photo-affinity linker coated (PALC) slides under 365 nm ultraviolet irradiation. The small molecules on the microarrays with specific binding ability might immobilize target protein, which were characterized by high resolution micro-confocal Raman spectrometer. Using this method, more than a dozen components of Shenqi Jiangtang granules (SJG) were made into small molecule probe (SMP) microarrays. As a result, 8 of them had been identified to have α-glucosidase binding ability according to characteristic Raman shift at about 3060 cm−1. These compounds were further verified by different small molecule-protein interaction analysis methods, including contact angle D-value, surface plasmon resonance (SPR) and molecular docking. The results showed that Ginsenosides Mb, Formononetin and Gomisin D exhibited the strongest binding ability. In conclusion, the HRMR-PM strategy for investigating the interaction between target proteins and small molecules has the advantages such as high throughput, low sample consumption and fast qualitative characterization. This strategy is universal which can be applied in the study of in vitro binding activity of various types of small molecules to target proteins.
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•Small molecule microarray was fabricated by photo-crosslinking.•This strategy has the advantage of high throughput and low consumption of small molecules and target protien.•The strategy is universally applicable to studying the binding activity of small molecules to target proteins in vitro.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Step‐scan Fourier‐transform infrared spectroscopy (ssFTIR) simultaneously provides the spectroscopic and kinetic information of a given reaction. ssFTIR has been extensively employed to acquire the ...transient absorption and emission spectra in gas phase for identifying unstable species, for example, various Criegee intermediates, and elucidating the dynamics and kinetics of the reaction, such as the molecular elimination dynamics of haloalkenes and the bimolecular reactions involving chlorine atoms and singlet oxygen atoms. In addition to gaseous studies, ssFTIR has been also utilized to record the time‐resolved difference spectra of the photochemical reactions in condensed phases, such as the photolysis of metal–ligand complexes, photocycles of the retinal proteins, coordination capability of solvents to unstable transient species, chemical reactions of atmosphere‐related molecules in aqua, and the exciplex dynamics of organic light emitting materials. Moreover, my group has pioneered the recording of the transient thermal infrared emission of gold nanostructures upon photoexcitation. The experimental setups and the working principles for probing the time‐resolved infrared absorption and emission in condensed phases will be revealed and a number of studies on chemical, biological, and materials systems will be described. These reported results demonstrate that ssFTIR is a versatile tool for exploring the properties of novel materials and photoreactions in condensed phases.
Step‐scan Fourier‐transform infrared spectroscopy (ssFTIR) operated in absorption and emission modes is a versatile tool to explore the properties of novel materials and photoreactions in condensed phases.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In recent years, photoacoustic spectroscopy has emerged as an invaluable tool for the accurate measurement of light absorption by atmospheric aerosol. Photoacoustic instruments require calibration, ...which can be achieved by measuring the photoacoustic signal generated by known quantities of gaseous ozone. Recent work has questioned the validity of this approach at short visible wavelengths (404 nm), indicating systematic calibration errors of the order of a factor of 2. We revisit this result and test the validity of the ozone calibration method using a suite of multipass photoacoustic cells operating at wavelengths 405, 514 and 658 nm. Using aerosolised nigrosin with mobility-selected diameters in the range 250–425 nm, we demonstrate excellent agreement between measured and modelled ensemble absorption cross sections at all wavelengths, thus demonstrating the validity of the ozone-based calibration method for aerosol photoacoustic spectroscopy at visible wavelengths.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
X-ray spectrometers based on superconducting transition edge sensors (TESs) are promising in the spectroscopy research. For several X-ray light source facilities in Shanghai, deployment of TES-based ...spectrometers is proposed. This paper introduces the work on data processing for a TES-based X-ray spectrometer prototype developed at ShanghaiTech University. A data acquisition software is designed and programmed for multi-pixel data recording. The signal analysis method is optimized to best realize the performance of the prototype. We have achieved 12-channel simultaneous data acquisition and better than 9 eV resolution in the range from 2 to 9 keV for 11 TES pixels.
General properties of a Johann-type spectrometer equipped with spherically bent crystals are described leading to simple rules of thumb for practical use. They are verified by comparing with results ...from Monte-Carlo studies and demonstrated by selected measurements in exotic-atom and X-ray fluorescence research.
•Ultimate-resolution highly stable Johann spectrometer with excellent peak/background ratio•Detailed Monte-Carlo studies and rules of thumb for quick assessment of experimental needs•Performance demonstrated with novel results in exotic-atom and fluorescence X-ray experiments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Monitoring systems for color and concentration of liquids have an important role in improving the fabrication process stably, not only in pipelines but also in microchannels. Our suggested in-line ...micro-spectrometer with an elastic structural color filter has detectability for color and concentration changes with a 40-mm size. The sequence of our device is the following: (1) the elastic structural color filter splits the white light from an LED, (2) the split light transmits the sample liquid, and (3) a photodiode receives the transmitted light. The structural color polymer is mechanically compressed inside the micro-spectrometer, leading to fixing the optical path even though the light wavelength is changed continuously. We fabricated the elastic structural color polymer with 200 nm silica nanoparticles and PEGPEA (poly- (ethylene glycol) phenyl ether acrylate). The prototype of the in-line micro-spectrometer with a red (λ = 596 nm) filter showed the detectability of the difference between yellow and green dyes. Moreover, the micro-spectrometer successfully distinguished the concentration of green-dyed water. This proposed in-line micro-spectrometer would contribute to developing in-line microfluidic color monitoring systems for biochemical analyses and material production.
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•An in-line micro-spectrometer is developed for microfluidic monitoring systems.•Compression of a structural color polymer brings continuous color scanning.•The resolution of our device was 40 – 80 nm in full width at half maximum.•The device distinguished yellow and green samples by slope of linear approximation.•The concentration change of the samples could be detected in a 1-mm2 capillary.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The emergence of silicon photonics over the past two decades has established silicon as a preferred substrate platform for photonic integration. While most silicon-based photonic components have so ...far been realized in the near-infrared (near-IR) telecommunication bands, the mid-infrared (mid-IR, 2–20-μm wavelength) band presents a significant growth opportunity for integrated photonics. In this review, we offer our perspective on the burgeoning field of mid-IR integrated photonics on silicon. A comprehensive survey on the state-of-the-art of key photonic devices such as waveguides, light sources, modulators, and detectors is presented. Furthermore, on-chip spectroscopic chemical sensing is quantitatively analyzed as an example of mid-IR photonic system integration based on these basic building blocks, and the constituent component choices are discussed and contrasted in the context of system performance and integration technologies.
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