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We characterize an efficient and nearly-noiseless parametric frequency upconverter. The ultra-low noise regime is reached by the wide spectral separation between the input and pump frequencies and the low pump frequency relative to the input photons. The background of only ≈100 photons per hour is demonstrated. We demonstrate phase preservation in a frequency upconversion process at the single-photon level. We summarize our efforts to measure this ultra-low noise level, and discuss both single-photon avalanche photodiode measurements and a photon-counting transition edge sensor (TES) measurements. To reach the required accuracy, we supplemented our TES with a dark count reduction algorithm. The preservation of the coherence was demonstrated by simultaneously upconverting the input of each arm of a Mach-Zehnder interferometer through high interference fringe contrast. We observe fringe visibilities of ≥0.97 with faint coherent input.

This paper reports on the performance of the Kimoto 180 sampler and the Wedding ambient PM10 beta gauge sampler. Monodisperse ammonium fluorescein test particles were generated in the laboratory and used to determine the penetration curve of the Kimoto 180 cyclonic inlet. It was found that the actual DpaSOof the Kimoto 180 inlet, 3.5 (xm, is much lower than the designated standard value, 10 um. In the field test, the two beta gauge samplers were collocated with an Andersen SA1200 high-volume sampler to compare their measured daily average PM10 concentrations. The low Dpa50 of the Kimoto 180 inlet serves to explain why its daily average PM10 concentrations were much lower than the actual PM10 concentrations found in the field study. In addition, the PM10 concentrations of the Kimoto 180 beta gauge sampler were found to be seriously affected by the water vapor content of the ambient air. In contrast, the daily average PM10 concentrations of the Wedding beta gauge sampler were found to be more accurate, and influences by ambient conditions were insignificant.

Using single-shot pump-probe spectroscopy, the carrier relaxation and phonon oscillation in highly photo-excited bismuth are coherently controlled with double-pulse excitation. Beside phonon amplitude and phase, the magnitudes of monotonic decays also oscillate with interpump delay.

Understanding the characteristics of the size distribution of ambient black carbon (BC) in distinct environments is critical because the influence of BC aerosols on climate, visibility, and human health depends strongly on the distribution of BC aerosols over the particle size spectrum. In this study, a novel method for determining the mass size distribution of BC in atmospheric aerosols was developed. This size-segregation method relies on measuring BC in parallel using two aethalometers, one of which is used to measure the total BC (BCT) mass concentration as a reference level and the other is used to measure the BC (BCi) mass concentration for BC sizes below specific particle sizes that are selected using a size cut-off inlet. In this study, this method was applied to measure BC in atmospheric samples at an urban traffic site. The aethalometers were operated continually from December 15, 2012 to January 31, 2013, and from February 15, 2013 to March 31, 2013. The measurement results presented in this paper are for the diurnal variation patterns, average concentrations, mass fractions, and size distributions of BC aerosols. The results indicate that BCT mass concentration is approximately 2.8 m gm � 3 in the Taipei urban area. The levels of BC at this sampling site were affected markedly by traffic emission levels and local wind speed. At the sampling site, the average BC2.5/BCT ,B C1.0/BCT ,B C0.5/BCT ,B C0.25/BCT, and BC0.1/BCT were 0.96 � 0.04, 0.92 � 0.07, 0.89 � 0.04, 0.73 � 0.10, and 0.18 � 0.08, respectively. The results indicate that approximately 90% of the BC aerosols were smaller than 0.5 mm, that most of the BC aerosols (55%) were in the size range of 0.1e0.25 mm, and that approximately 18% of the BC aerosols were ultrafine. Moreover, the daily average mass size distribution of BC exhibited a single accumulation mode at 0.16 mm at this sampling site. The mode of the BC mass size distribution at rush hour (9 AM) was only 0.14 mm, which is smaller than the daily average. Moreover, the mode of the BC mass size distribution at an early morning hour (3 AM) was 0.18 mm, and a minor coarse mode was also observed during this period. The results further revealed that the geometric diameter (Dpg) of the BC aerosols varied between 0.14 and 0.22 mm and the geometric standard deviation (sg) of these BC aerosols ranged between 1.4 and 2.3 during the sampling period. Because BC exhibits extremely low chemical reactivity; the size distribution of BC in the atmosphere does not change substantially except through coagulation.

This study investigates the correlation between Black Carbon (BC) mass and particle number concentrations in various particle size ranges in Taipei urban area. The concentrations of BC mass and particle numbers (ranging from 10–560 nm, N10–560) were measured continuously from 2006 to 2010. Long–term measurement results of this study demonstrated that BC mass concentrations in the spring, summer, autumn, and winter were 3.3 μg m−3, 3.2 μg m−3, 2.4 μg m−3, and 3.1 μg m−3, respectively. Additionally, the N10–560 concentrations in the spring, summer, autumn, and winter were 1.5 × 104 particles cm−3, 1.7 × 104 particles cm−3, 1.1 × 104 particles cm−3, and 1.4 × 104 particles cm−3, respectively. In the autumn, the lowest BC mass and particle number concentrations were mostly likely owing to the high wind speed condition that favored dispersion of particulate matter. Additionally, the highest particle number concentrations observed in the summer can be due to that the activities of the chemical nucleation reactions in the summer are more intense than those in other seasons. In this sampling site, the number fractions for N10–18, N18–32, N32–56, N56–100, N100–180, N180–320 and N320–560 were 4.39%, 15.38%, 26.31%, 27.35%, 16.89%, 7.17% and 2.51%, respectively. Hourly BC mass concentrations are significantly positively correlated with hourly N100–180 concentrations at the sampling site. In the summer, a clear increase in N10–560/BC is observed during the noontime period, coincident with maximum ambient temperature. Secondary particles through the photochemical nucleation heavily impact the size range of 56–100 nm, following by 100–180 nm and 32–56 nm in this study.

Crystalline tellurium undergoes amorphization after irradiation with strong femtosecond pulses. Steady-state reflectivity and single-shot transient reflectivity studies suggest the amorphization is due to thermal melting rather than non-thermal switching.

This study investigates the temporal characteristics of black carbon and its potential emission sources, as well as the fractions of BC in PM2.5 levels in Kaohsiung urban area, which is an industrial city in southern Taiwan. Concentrations of BC and PM2.5 are monitored continuously from March 2006 to February 2010, using an aethalometer and a tapered element oscillating microbalance monitor. Additionally, the presence of organic compounds (or UV enhanced species) in particles at the sampling site is determined using the Delta-C (UVBC-BC) value. According to long-term measurement results, BC and PM2.5 concentrations are 3.33 and 34.0 μg m(-3), respectively, in the Kaohsiung urban area. The ratio of BC/PM2.5 is approximately 11 %. Low concentration of BC and PM2.5 in the summer of this study period is mostly likely owing to meteorological conditions that favored dispersion of local air pollutants. Nevertheless, BC concentrations peaked markedly during morning hours (7:00-11:00), likely owing to local traffic congestion. Measurement results suggest that BC is released from local traffic activities and emitted from industrial activities at this sampling site. Additionally, Delta-C values are significantly higher than zero during January-March and November-December periods in this industrial urban area, implying that UV enhanced species can be observed. At this sampling site, these UV enhanced species do not only originate from household activity and solid waste burning but also release from industrial activities. The elevated Delta-C values during nighttime (18:00-6:00) in the autumn and winter seasons are likely related to those UV enhanced species in the atmosphere, which can be condensed on particle surface under low temperature conditions. According to long-term measurement results, significantly positive Delta-C values can be observed under temperatures20 °C and relative humidity of 60-75 % in this study. Despite the household activity and solid waste burning, the major sources of particles that are bound with UV enhanced species in this sampling site are industrial parks and a coal-fired power plant.

The new portable microAeth® AE51 (AE51) is very useful for assessing occupational and environmental exposure to black carbon (BC) aerosols in epidemiological research. However, information about the performance of AE51 is limited. This study compares AE51 with the widely used, rack-mounted Aethalometer® AE31 (AE31) by evaluating the real-time performance of these two instruments, as carried out at a traffic site. Additionally, an optimized noise-reduction averaging (ONA) algorithm is adopted to eliminate the negative values in the BC data sets. Negative BC levels may be present using AE51 at low actual BC levels or at a high time-resolution. The negative values can be eliminated very effectively by the ONA method. The time-variation of the 5 min BC levels measured using AE51 is highly consistent with that measured using AE31. Loading effects on the measured BC levels are observed during the sampling period. Additionally, the correcting factor, k, is evaluated, in which the correcting factors are 0.0033 and 0.0039 for AE31 and AE51, respectively, when used to monitor the BC levels at this traffic site. The analytical results indicate that the BC levels are underestimated by up to 15% when the ATN-ATN0 increases to ~40. The measurement results also reveal that the BC levels measured by AE51 are approximately 14% higher than those measured using AE31. These results may be due to the different aerosol deposition velocities and mass attenuation cross-section parameters (σATN) of the two instruments.

Zinc 5-(4-carboxy-phenylethynyl)-10,20-biphenylporphines bearing various substituents on the 10,20-phenyl rings are studied for their electrochemical and spectroelectrochemical properties. Cyclic voltammetry and optically transparent thin-layer electrochemical measurements suggest that the first reductions of these porphyrins should be the reduction reaction of the carboxylic protons. For the porphyrin ring reactions, our study shows that the redox properties can be significantly affected by the alkoxyl chains on the 10,20-phenyl rings.

Information on the effect of open-field burning of agricultural residues on ambient black carbon (BC) mass and size-resolved particle number concentrations is scarce. In this study, to understand the effect of such open-field burning on short-term air quality, real-time variations of the BC mass and size-resolved particle number concentrations were monitored before and during a corn straw open-field burning episode at a rural site. Correlations between the BC mass and size-resolved particle number concentrations during the episode were investigated. Moreover, the particle number size distribution and absorption Ångström exponent were determined for obtaining the characteristics of aerosol emissions from the corn straw open-field burning. The results can be used to address public health concerns and as a reference for managing similar episodes of open-field burning of agricultural residues.

In its early stages, cancer does not appear very different from the surrounding areas. Inexperienced physicians do not always accurately locate all cancer areas suitable since there are similarly colored and outlined organ surfaces. However, potential early-stage cancer has certain surface symptoms in terms of the color and the distribution of blood tubes. The main purpose of this work is to provide information concerning the identification of early-stage cancer during endoscopic examination. The proposed algorithm has been developed thorough image processing techniques, thereby incorporating and adjusting the statistical value to determine correct lesion recognition. There is 80% in accuracy to allocate the suspect lesion location from the three video experiments.

Absolute, ultrafast measurements of the optical nonlinearity in gases are performed using spectral interferometry in thin targets. Notably, we are able to isolate the rovibrational component of the nonlinearity using resonant two-beam coupling.

Many of the factors influencing the adsorption of volatile organic compounds by activated carbon fibers (ACFs) have been widely studied. However, most of them were investigated at low concentrations (500 ppm or less) and at low adsorption temperatures (lower than 100 °C). This study was to determine simultaneously the oxidation and adsorption of toluene onto activated carbon fibers (ACFs) at high concentration and high adsorption temperatures. We tested three ACFs, four inlet concentrations of toluene (700, 1,200, 1,600, and 2,000 ppm), and four adsorption temperatures (25, 50, 75, and 200 °C). The composition and morphology of the ACFs were also analyzed using BET, FTIR, EA, and FESEM. The results indicated that the best toluene adsorption capacity was for 569 mg/g ACFs at a toluene concentration of 1,200 ppm and at 25 °C. A combination of low O content and high mesopore volume was desirable for ACFs with a high toluene adsorption capacity at high toluene concentrations. Moreover, the breakthrough time decreased with increasing toluene concentration, and the adsorption capacity of toluene increased significantly when the inlet concentration of toluene increased to 1,200 ppm. The data also indicated that the breakthrough time and the adsorption capacity of toluene decreased with increasing adsorption temperature. The outlet concentration of toluene did not reach 1,200 ppm when adsorption was saturated at 200 °C, as the oxygen functional groups on the ACF surface had reacted with toluene to form other compounds.

Oxidative stress can result in insulin resistance, a primary cause of type-2 diabetes. Methylglyoxal (MG), a highly reactive dicarbonyl metabolite generated during glucose metabolism, has also been confirmed to cause pancreatic injury and induce inflammation, thereby resulting in insulin resistance. Recently, resveratrol has been reported to exert antioxidant properties, protecting cells from the generation of reactive oxygen species (ROS). The aim of this study was to evaluate resveratrol activation of nuclear factor erythroid 2-related factor 2 (Nrf2) to attenuate MG-induced insulin resistance in Hep G2 cells. Therefore, the molecular signaling events affecting resveratrol-mediated heme oxygenase-1 (HO-1) and glyoxalase expression levels were further investigated in this study. Our findings indicated that resveratrol activated the extracellular signal-regulated kinase (ERK) pathway but not the p38 or c-Jun N-terminal kinase (JNK) pathways, subsequently leading to Nrf2 nuclear translocation and elevation of HO-1 and glyoxalase expression levels. Moreover, resveratrol significantly elevated glucose uptake and protected against MG-induced insulin resistance in Hep G2 cells. In contrast, depletion of Nrf2 by small interfering RNA (si-RNA) resulted in the abrogation of HO-1 and glyoxalase expression in the MG-treated resveratrol group in Hep G2 cells. Administration of an appropriate chemopreventive agent, such as resveratrol, may be an alternative strategy for protecting against MG-induced diabetes.

Biodiesel is a prospective and promising fuel for diesel engines. However, some aspects need improvement, to develop into an ideal fuel, such as flow properties at low temperatures and storage stability at high temperatures with exposure to the air. Thermal analysis is an efficient tool for measuring properties, such as crystallization temperature, and thermal and oxidative stabilities. In this study, the thermal behaviors of biodiesel at low and high temperatures were investigated by using thermogravimetric analyzer, differential scanning calorimetry, pressurized differential scanning calorimetry (PDSC), and sorption analyzer (SA). The soy biodiesel was obtained through a transesterification reaction with a homogeneous catalyst. The constituents of the soy biodiesel as determined by gas chromatography show that methyl esters content was 99 % and of these 84 % were unsaturated fatty acids. TG results illustrate that the total weight loss of the biodiesel was 99 % below 300 °C under nitrogen flow, indicating a high purity biodiesel. The onset decomposition temperature and the peak temperatrue of the soy biodiesel were 193 and 225 °C, respectively, implying the biodiesel has good thermal stability. PDSC results show that the oxidation onset temperature of the soy biodiesel was 152 °C, and the oxidative induction time was 24 min. DSC results demonstrate that the onset crystallization temperature of the soy biodiesel was 1.0 °C. The SA results point out that with increasing temperature and humidity, the soy biodiesel absorbed more water, and in which humidity was the dominant factor. The water absorption and desorption of the soy biodiesel is a non-reversible process. The preferable storage conditions for soy biodiesel occur when humidity is less than 30 % and the temperature is less than 30 °C. In summary, thermal analysis is a faster alternative for thermal behavior studies as compared with conventional standard methods.

We discuss recent experiments and calculations of the high-intensity optical nonlinearity in gases. Spectral interferometry measurements of the nonlinear optical response of air constituents to laser intensities near the ionization threshold are performed. A calculation of the phase shift caused by a plasma grating created by interference between the pump and probe beams in a transient birefringence measurement suggests that experimental techniques measuring cross phase modulation of a probe pulse by a strong pump pulse are unreliable for studying the optical nonlinearity when the pump and probe pulses are of the same wavelength. An interferometric measurement of the electron density in a filament is also performed. The peak elec-tron density measured is consistent with a model that includes plasma defocusing, but not higher-order Kerr terms. These tech-niques promise to improve the quantitative understanding of nonlinear optics near the ionization threshold and filamentation.

This study investigates temporal variations in PM levels in Taipei bus terminal and assesses exposure levels for bus terminal workers. Measurement results show that temporal variations in PM levels in the waiting room and on the platform of this indoor bus terminal were strongly associated with bus traffic volume. The PM10, PM2.5, and ultrafine particle (UFP) levels on the bus platform were 1.9, 2.0, and 1.2 times higher than those inside the waiting room, respectively. Additionally, PM10 and PM2.5 levels on the platform were approximately 2.3 and 2.8 times higher than those at an ambient monitoring station, respectively. Measurement results indicate that the major PM source inside this bus terminal is diesel buses and that PM can be trapped in this semi-confined bus terminal to a far greater extent than in typical open-air bus stations. Daily PM exposure levels for station ticket inspectors who check passenger tickets in the waiting room and manage arriving and departing buses on the bus platform are assessed. Daily PM exposure levels for station ticket inspectors during different shifts are calculated based on average PM levels and working time spent in the waiting room and on the platform. Based on observational results, station ticket inspectors spend approximately 80–85% and 15–20% of their working time in the waiting room and on the platform, respectively. Daily PM10 and PM2.5 exposure levels for station ticket inspectors were approximately 1.3–1.5 and 1.6–1.8 times higher than those in the outdoor atmosphere, respectively. Additionally, daily UFP exposure levels for station ticket inspectors were approximately 5.6–7.2 times higher than those in the urban background. Measurement results demonstrate that potential health risk induced by PM is high for station ticket inspectors who work for long periods at this indoor bus terminal.

Commuters spend considerable time, in some cases up to 1-2 h a day, traveling in metro trains. However, few studies have compared air quality between trains traveling above-ground and underground. This study measures the PM(subscript 10), PM(subscript 2.5), particle number (PN) and CO2 levels inside metro trains traveling in underground tunnels and on elevated tracks on a metro line in the Taipei metro system. The results demonstrated that PM(subscript 10), PM(subscript 2.5 ) and CO2 levels inside metro trains traveling in underground environments are approximately 20-50% higher than those in above-ground environments. However, PN levels inside metro trains traveling in underground environments are approximately 20% lower than those in above-ground ones. These measurement results reveal that levels of pollutant species inside the metro trains are significantly affected by traveling environmental conditions - in underground tunnels or on elevated tracks. Moreover, the levels of pollutant species inside the metro trains traveling on the same route are also different in different traveling directions. Fine PM inside the metro trains is transferred from the outside and significantly influenced by the surrounding conditions of the trains. Additionally, a high fraction of large coarse PM (＞ 10 μm) is observed inside the metro trains, possibly due to re-suspension by the movement of commuters. The measurement results show that, unlike PM, which is transferred from outside environments, CO2 inside metro trains is elevated internally by exhalation from commuters. Clearly, CO2 exhaled by commuters could accumulate inside metro trains and, compared to PM, is not as easily removed by the ventilation system when air circulation does not provide enough fresh air in the metro trains, particularly in trains traveling in underground environments.

The aim of this research was to use metal catalysts supported on activated carbon fibers (ACFs) to remove 16 species of polycyclic aromatic hydrocarbons (PAHs) from incineration flue gas. We tested three different metal loadings (0.11 wt%, 0.29 wt%, and 0.34 wt%) and metals (Pt, Pd, and Cu), and two different pretreatment solutions (HNO3 and NaOH). The results demonstrated that the ACF-supported metal catalysts removed the PAHs through adsorption and catalysis. Among the three metals, Pt was most easily adsorbed on the ACFs and was the most active in oxidation of PAHs. The mesopore volumes and density of new functional groups increased significantly after the ACFs were pretreated with either solutions, and this increased the measured metal loading in HNO3–0.48% Pd/ACFs and NaOH–0.52% Pd/ACFs. These data confirm that improved PAH removal can be achieved with HNO3–0.48% Pd/ACFs and NaOH–0.52% Pd/ACFs.

As of 2010, the Taipei mass rapid transit (MRT) comprised 8 rapid transit lines stretching 90.5 km and linking 82 stations. Currently, over 1.4 million commuters a day travel on the Taipei MRT system. However, information related to the characteristics of indoor air quality at ground-level and in underground stations in the Taipei MRT system is limited. This study used portable monitors to measure the PM10, PM2.5, particle number (PN), CO, and CO2 levels at an underground (UG) and two ground-level (AG1 and AG2) MRT stations on the same rapid transit line. All measurements were taken between August 20 and November 12, 2010. The mean PM10 and PM2.5 levels in underground environments (underground ticket hall and platform of the UG and underground platform of the AG1) are approximately 51–65 μg m−3 and 25–40 μg m−3, respectively. Additionally, the mean PM10 and PM2.5 levels in ground-level indoor environments (ground-level ticket halls of the AG1 and AG2) are approximately 44–48 μg m−3 and 26–29 μg m−3, respectively. Measurement results reveal that PM levels in underground environments are greater than those in ground-level indoor environments. PM levels in ground-level indoor environments are strongly associated with outdoor ambient PM levels, while PM levels in underground environments are less influenced by outdoor ambient conditions. The presence of coarse PM in the underground environments may have been generated internally through the mechanical friction processes or re-suspended by the movement of commuters, and fine PM is likely transferred from its source outside the station. The mean PM2.5-to-PM10 ratios in underground environments are 0.45–0.79, and at ground-level indoor environments are approximately 0.58. Based on differences in the environment conditions among these selected locations, it is reasonable to assume that PM2.5-to-PM10 ratios in underground and ground-level MRT stations will not be consistent, even those on the same metro line. Furthermore, low PN and CO levels are observed in underground environments. Mean PN and CO levels in underground environments are 9.5 × 103–1.7 × 104 particles cm−3 and 0.30–0.48 ppm, respectively, and significantly lower than those in outdoor environments by approximately 0.3–0.6 times. However, the CO2 levels in underground environments are 574–1051 ppm and significantly higher than those in outdoor environments, by approximately 1.3–2.4 times. The CO2 in underground environments is likely elevated by the exhalation of commuters.

The Taipei Bus Station is the main transportation hub for over 50 bus routes to eastern, central, and southern Taiwan. Daily traffic volume at this station is about 2500 vehicles, serving over 45,000 passengers daily. The station is a massive 24-story building housing a bus terminal, a business hotel, a shopping mall, several cinemas, offices, private residential suites, and over 900 parking spaces. However, air quality inside this bus terminal is a concern as over 2500 buses are scheduled to run daily. This study investigates the PM10, PM2.5, UFP and CO2 levels inside and outside the bus terminal. All measurements were taken between February and April 2010. Measurement results show that coarse PM inside the bus terminal was resuspended by the movement of large numbers of passengers. The fine and ultrafine PM in the station concourse were from outside vehicles. Moreover, fine and ultrafine PM at waiting areas were exhausted directly from buses in the building. The CO2 levels at waiting areas were likely elevated by bus exhaust and passengers exhaling. The PM10, PM2.5 and CO2 levels at the bus terminal were lower than Taiwan’s EPA suggested standards for indoor air quality. However, UFP levels at the bus terminal were significantly higher than those in the urban background by about 10 times. Therefore, the effects of UFPs on the health of passengers and workers must be addressed at this bus terminal since the levels of UFPs are higher than >1.0 × 105 particles cm−3.

The levels of ultrafine particles (UFPs) and their size distributions on a highway electronic toll collection (ETC) lane were measured from October 30 to November 1 and November 5 to November 6, 2008. The hourly UFP levels measured at the highway ETC lane were 1.3 × 104–1.9 × 105 particles cm−3 (mean = 9.4 × 104 particles cm−3). Compared with urban UFP levels, average UFP levels at the highway ETC lane were about 5–10 times higher than those previously measured in urban areas, indicating that a considerable amount of UFPs were exhausted from vehicles. At the highway ETC lane, the average UFP number size distribution had a dominant mode at about 10 nm and a minor mode at about 33 nm. Measurement results indicate that nucleation mode particles remained at relatively high levels compared to Aitken mode and accumulation mode particles at the highway ETC lane. This study identifies the impacts of traffic volumes and wind speeds on ambient UFP levels. Measurement results show that the elevated UFP levels resulting from traffic volume decreased exponentially as wind speed increased on the highway when wind speed was 2.0 m s−1 due to local turbulent mixing causes UFPs at high wind speeds. According to measurement results, high levels of UFP were observed at low wind speeds and under high traffic volumes.

This study measured ultrafine particle (UFP) levels and their size distributions in the Hsuehshan tunnel from August 12 to 19, 2009, using a Fast Mobility Particle Sizer. Measurement results demonstrate that traffic volume, the slope of the tunnel (downhill or uphill) and the ventilation system affected UFP levels inside the tunnel. Average UFP levels were about 1.0 × 10 5 –3.0 × 10 5 particles cm −3 at normal traffic volume. A traffic jam in the tunnel could raise UFP levels to over 1.0 × 10 6 particles cm −3 . UFP levels at the uphill bore were significantly higher than those at the downhill bore due to high UFP levels exhausted from vehicles going uphill at high engine load conditions. UFP levels eventually diluted 10–50% with fresh air from tunnel air shafts. Gas-to-particle condensation conversion markedly produced nucleation mode particles at the tunnel entrance section. Observations also showed Aitken mode particles markedly formed by coagulation growth of nucleation mode particles in the tunnel middle section and exit section. That is, the particle size distributions changed significantly inside the tunnel. Measurement results suggest that particles in the Aitken mode in the long tunnel governed UFP levels.

Objective The aim of the present study is to compare the accuracy in using laboratory data or clinical factors, or both, in predicting probability of dying within 7 days of hospice admission in terminal cancer patients. Methods We conducted a prospective cohort study of 727 patients with terminal cancer. Three models for predicting the probability of dying within 7 days of hospice admission were developed: (i) demographic data and laboratory data (Model 1); (ii) demographic data and clinical symptoms (Model 2); and (iii) combination of demographic data, laboratory data and clinical symptoms (Model 3). We compared the models by using the area under the receiver operator curve using stepwise multiple logistic regression. Results We estimated the probability dying within 7 days of hospice admission using the logistic function, P = Exp(βx)/[1 + Exp(βx)]. The highest prediction accuracy was observed in Model 3 (82.3%), followed by Model 2 (77.8%) and Model 1 (75.5%). The log[probability of dying within 7 days/(1 − probability of dying within 7 days)] = −6.52 + 0.77 × (male = 1, female = 0) + 0.59 × (cancer, liver = 1, others = 0) + 0.82 × (ECOG score) + 0.59 × (jaundice, yes = 1, no = 0) + 0.54 × (Grade 3 edema = 1, others = 0) + 0.95 × (fever, yes = 1, no = 0) + 0.07 × (respiratory rate, as per minute) + 0.01 × (heart rate, as per minute) − 0.92 × (intervention tube = 1, no = 0) − 0.37 × (mean muscle power). Conclusions We proposed a computer-assisted estimated probability formula for predicting dying within 7 days of hospice admission in terminal cancer patients.

The PM10 and PM2.5 levels at a highway toll station were monitored from October to December 2008. Experimental results show that hourly average PM10 and PM2.5 levels at the highway toll station were 10.6–208.4 μg/m 3 and 6.6–187.9μg/m 3 , respectively. Additionally, the PM2.5-to-PM10 ratio at the highway toll station was 0.73, indicating that emissions from traffic sources are dominant in PM2.5 fraction. At the highway toll station, the time variations of the PM10 and PM2.5 levels were not strongly correlated with traffic volumes; however, traffic on the highway markedly elevated ambient PM10 and PM2.5 levels. The PM10 and PM2.5 levels at the highway toll station are higher than those at monitoring stations in the vicinity to the toll station by factors of 1.3–1.4 and 1.4–1.8 times, respectively. The low wind speeds and low mixing-layer heights lead to relatively high PM10 and PM2.5 levels. Moreover, high wind speed also could have resulted in high PM10 and PM2.5 levels due to the re-suspension of particulate matter under well dispersed conditions. Measurements indicate that both traffic emissions and meteorological conditions drive PM10 and PM2.5 levels at the highway toll station.

The Taipei main station is a major transfer station in the Taipei Rapid Transit System and is located at the center of Taipei metropolitan areas. This study investigates particle mass concentrations and size distributions at the concourse in this underground station using an optical particle counter. On-site measurements were taken during January-February 2008. Experimental results show that PM10 and PM2.5 levels in the Taipei main station were 9.83-104.26 μg/m3 and 3.84- 59.74 μg/m^3, respectively. The lognormal mass size distribution in the Taipei main station had two modes; one near 0.27 μm and the other at about 12.5 μm. Additionally, the mean mass concentrations were governed by particles with coarse PM. Measurement results also suggest that average PM10 and PM2.5 levels in the indoor station were about 0.70 and 0.53 times those outdoors, respectively. The PM levels in the indoor station and outdoors were positively correlated, indicating that PM levels at the concourse in the Taipei main station are significantly influenced by outdoor ambient PM levels. Moreover, the low PM2.5-to-PM10 ratio at the concourse in the Taipei main station was likely the result of coarse PM being re-suspended in the station concourse due to passenger movement.

The number and surface area concentration of ultrafine particles in an iron foundry is of interest as freshly generated ultrafine particles are produced by metal melting, pouring and molding processes. This study measured the number and surface area concentrations of ultrafine particles and their size distributions in an iron foundry using a scanning mobility particle sizer (SMPS). The 10-100 nm ultrafine particle number concentrations (NC(0.01-0.1)) and surface area concentrations (SC(0.01-0.1)) measured at the iron foundry were 2.07 x 10(4) to 2.82 x 10(5)particles cm(-3) and 67.56 to 2.13 x 10(3)microm(2)cm(-3), respectively. The concentrations changed dramatically depending on on-site manufacturing conditions. The NC(0.01-0.1) levels in the iron foundry were approximately 4.5 times higher on average compared with those in the outdoor ambient environment. These measurement results indicate that the presence of extra particles in the workplace air is within the ultrafine range. Additionally, the analytical results suggest that the number mode diameter can be used to estimate the SC(0.01-0.1) levels using the NC(0.01-0.1) levels. Moreover, the ultrafine particle number mode diameter was found to be about 46.1 nm in the iron foundry.

The electronic, rotational, and vibrational components of the ultrafast optical nonlinearity in ${\mathrm{H}}_{2}$ and ${\mathrm{D}}_{2}$ are measured directly and absolutely at intensities up to the ionization threshold of $\ensuremath{\sim}{10}^{14}\phantom{\rule{0.16em}{0ex}}{\mathrm{W}/\mathrm{cm}}^{2}$. As the most basic nonlinear interactions of the simplest molecules exposed to high fields, these results constitute a benchmark for high-field laser-matter theory and simulation.

Microscopy based on non-fluorescent absorption dye staining is widely used in various fields of biomedicine for 400 years. Unlike its fluorescent counterpart, non-fluorescent absorption microscopy lacks proper methodologies to realize its in vivo applications with a sub-femtoliter 3D resolution. Regardless of the most advanced high-resolution photoacoustic microscopy, sub-femtoliter spatial resolution is still unattainable and the imaging speed is relatively slow. In this paper, based on the two-photon photoacoustic mechanism, we demonstrated a in vivo label free laser-scanning photoacoustic imaging modality featuring high frame rates and sub-femtoliter 3D resolution simultaneously, which stands as a perfect solution to 3D high resolution non-fluorescent absorption microscopy. Furthermore, we first demonstrated in vivo label-free two-photon acoustic microscopy on the observation of non-fluorescent melanin distribution within mouse skin.

The primary aim of this work is to explore the effect of resin content and the effect of substrate on the emission of benzene, toluene, ethylbenzene, and xylene (BTEX) and carbonyls from low-VOC water-based wall paint. Four low-volatile organic compound (VOC) paints include paints A (20% acrylic), B (30% acrylic), C (20% polyvinyl acetate), and D (30% polyvinyl acetate) were painted on stainless steel specimen for the study of resin effect. Green calcium silicate, green cement, and stainless steel were painted with paints A and C for the study of substrate effect. Concentrations of the VOCs in the chamber decreased with the elapsed time. Both resin type and resin quantity in paint had effects on VOC emissions. Paints with acrylic resin emitted less BTEX and carbonyls than paints with polyvinyl acetate resin. However, the effects of resin quantity varied with VOCs. Porous substrates were observed to interact more strongly with paints than inert substrates. Both green calcium silicate and green cement substrates have strong power of adsorption of VOCs from wall paints, namely toluene, formaldehyde, acetaldehyde, 2-butanone, methacrolein, butyraldehyde, and benzaldehyde. Some compounds like toluene, formaldehyde, and butyaldehyde were desorbed very slowly from green calcium silicate and green cement substrates.

We demonstrate up-conversion with no statistically significant background photons and a dynamic range of 15 decades. Near-infrared 920 nm photons were converted into the visible at 577 nm using periodically poled lithium niobate waveguides pumped by a 1550 nm laser. In addition to achieving statistically noiseless frequency up-conversion, we report a high degree of phase preservation (with fringe visibilities ≥ 0.97) at the single-photon level using an up-converting Mach-Zehnder interferometer. This background-free process opens a path to single-photon detection with no intrinsic dark count. Combined with a demonstrated photon-number preserving property of an up-converter, this work demonstrates the feasibility of noiseless frequency up-conversion of entangled photon pairs.

We demonstrate a background-free (to within experimental uncertainty) frequency up-converter. In addition, high fringe contrast at a single-photon-level in an up-converting interferometer is demonstrated, an enabling step towards faithful up-conversion of entangled photon pairs.

We demonstrate single-photon-level phase preservation in an up-converting interferometer. The up-conversion process is background-free to within experimental uncertainty, allowing high fringe contrast even at low photon levels. This enables faithful up-conversion of entangled photon pairs.

In order to assess the influence of dissolved hydrogen on the intergranular stress corrosion cracking (IGSCC) characteristics of Type 304 stainless steels treated with inhibitive chemicals, electrochemical corrosion potential (ECP) measurements and slow strain rate tensile (SSRT) tests were conducted in high temperature pure water. A number of thermally sensitized specimens were prepared and then pre-oxidized in a 288°C pure water environment with the presence of 300ppb dissolved oxygen for 360h. Most of the specimens were then separately treated with various inhibitive chemicals including powdered zirconium oxide (ZrO2), powdered titanium oxide (TiO2), and zirconyl nitrate [ZrO(NO3)2] via hydrothermal deposition at 150°C. Test environments with a dissolved oxygen concentration of 300ppb and various dissolved hydrogen concentrations at 288°C were created. Test results showed that the ECPs of the treated specimens were lower than that of the untreated one no matter what the dissolved hydrogen concentration...

High spatial and temporal resolutions are important advantages of optical imaging over other modalities. The recently developed spatial overlap modulation (SPOM) microscopy enables high resolution imaging by spatial modulation of double-beam overlap. However, SPOM suffers from bad temporal resolution and high system complexity. In this paper, we re-formulate the SPOM resolution theory and develop Virtual SPOM (vSPOM) microscopy. By one-way oversampling and convolution with differential filters, vSPOM not only realizes the same factor of spatial resolution improvement as SPOM, but overcome SPOM's major drawbacks. We demonstrated vSPOM on in vivo clinical images and find that the Gabor filter, which represents two-beam vSPOM, is the most effective among all vSPOM filters. The development of vSPOM enables easy incorporation of SPOM into any imaging system, and extends the use of SPOM to real-time in vivo applications.

In order to achieve high-resolution deep-tissue imaging, multi-photon fluorescence microscopy and photoacoustic tomography had been proposed in the past two decades. However, combining the advantages of these two imaging systems to achieve optical-spatial resolution with an ultrasonic-penetration depth is still a field with challenges. In this paper, we investigate the detection of the two-photon photoacoustic ultrasound, and first demonstrate background-free two-photon photoacoustic imaging in a phantom sample. To generate the background-free two-photon photoacoustic signals, we used a high-repetition rate femtosecond laser to induce narrowband excitation. Combining a loss modulation technique, we successfully created a beating on the light intensity, which not only provides pure sinusoidal modulation, but also ensures the spectrum sensitivity and frequency selectivity. By using the lock-in detection, the power dependency experiment validates our methodology to frequency-select the source of the nonlinearity. This ensures our capability of measuring the background-free two-photon photoacoustic waves by detecting the 2nd order beating signal directly. Furthermore, by mixing the nanoparticles and fluorescence dyes as contrast agents, the two-photon photoacoustic signal was found to be enhanced and detected. In the end, we demonstrate subsurface two-photon photoacoustic bio-imaging based on the optical scanning mechanism inside phantom samples.

Filter efficiency determination by means of the optical particle counting technique can yield information about the filter performance from a single set of upstream and downstream measurements. In principle, optical particle counters provide the possibility of a real time determination of particle size distribution and concentration. However, substantial errors in determination of the filtration efficiency may result from the performance characteristics of optical particle counters. This article presents results of a theoretical and experimental study analyzing the effects of variation of particle refractive index and coincidence on the sizing accuracy and counting ability of optical particle counters and the impact on the efficiency determination. Since both parameters, size and count, are critical for the determination of fractional collection efficiency and the most penetrating particle size, exemplary filter efficiency measurements with optical particle counters under various conditions are p...

Three kinds of dust materials, fly ash (MMAD : 6.28 μm), limestone (MMAD : 2.53 μm) and SAE fine dust (MMAD : 3.88 μm), have been used to test the dust cake compaction and its influence on the specific dust cake resistance coefficient at filtration velocity ranging from 1 to 9 cm/sec. An accurate laser dispacement system was used to determine dust cake thickness and the amount of dust cake compaction during filtration. In the range of filtration velocity tested, dust cake compaction has been found to occur. Higher filtration velocity results in larger amount of irreversible dust cake compaction and lesser amount of elastic dust cake compaction. The experimental specific dust cake resistance coefficient, K2, has also been found to increase with an increasing filtration velocity. For the three dusts tested, K2 relates to filtration velocity Vf as K2 ∞ Vn f, where n is 0.52, 0.38 and 0.43, for fly ash, limestone and SAE fine dust respectively. The theoretical K2 values predicted by the Rudnick-Happe...

In vivo harmonic generation microscopy (HGM) has been applied successfully in healthy human skin and can achieve a submicron resolution, similar to histopathologic examination, even at a penetration depth up to 270 μm. This study aims to investigate the clinical applicability of HGM imaging for differential diagnosis of nonmelanoma pigmented skin lesions. A total of 42 pigmented skin tumors, including pigmented basal cell carcinoma, melanocytic nevus, and seborrheic keratosis were evaluated by HGM ex vivo or in vivo. Based on the standard histopathologic characteristics, we established the corresponding HGM imaging criteria for each pigmented tumor. Diagnostic performance of HGM for differentiating nonmelanoma pigmented skin tumors was evaluated through the observers’ direct general assessment (overall evaluation) or the presence of two imaging criteria with the highest sensitivity and specificity (major criteria evaluation). Our results show that, based on the direct general assessment, the sensitivity is 92% [95% confidence interval (CI): 67 to 97%] and the specificity is 96% (95% CI: 83 to 99%); by major criteria evaluation, 94% sensitivity (95% CI: 70 to 99%) and 100% specificity (95% CI: 87 to 100%) are achieved. Our study indicates that HGM serves as a promising histopathological examination tool for noninvasive differential diagnostics of nonmelanoma pigmented skin tumors.

Role of inflammation-induced oxidative stress in the pathogenesis and progression of chronic inflammatory airways diseases has received increasing attention in recent years. Nuclear factor erythroid 2-related factor 2 is the primary transcription factor that regulates the expression of antioxidant and detoxifying enzymes.Graptopetalum paraguayenseE. Walther, a vegetable consumed in Taiwan, has been used in folk medicine for protection against liver injury through elevating antioxidation. Recently, we found that gallic acid is an active compound ofGraptopetalum paraguayenseE. Walther, which has been reported to inhibit T-helper 2 cytokines. Currently, we assumed thatGraptopetalum paraguayenseE. Walther may potentially protect against ovalbumin-induced allergy and airway inflammation. Results demonstrated thatGraptopetalum paraguayenseE. Walther ethanolic extracts (GPE) clearly inhibited airway inflammation, mucus cell hyperplasia, and eosinophilia in OVA-challenged mice. Additionally, GPE also prevented T-cell infiltration and Th2 cytokines, including interleukin- (IL-)4, IL-5, and IL-13 generations in bronchial alveolar lavage fluid. The adhesion molecules ICAM-1 and VCAM-1 were substantially reduced by GPE treatment mediated by Nrf2 activation. Moreover, GPE attenuated GATA3 expression and inhibited Th2 signals of the T cells. These findings suggested that GPE ameliorated the development of airway inflammation through immune regulation.

Nonlinear optics experiments measuring phase shifts induced in a weak probe pulse by a strong pump pulse must account for coherent effects that only occur when the pump and probe pulses are temporally overlapped. It is well known that a weak probe beam experiences a greater phase shift from a strong pump beam than the pump beam induces on itself. The physical mechanism behind the enhanced phase shift is diffraction of pump light into the probe direction by a nonlinear refractive index grating produced by interference between the two beams. For an instantaneous third-order response, the effect of the grating is to simply double the probe phase shift, but when delayed nonlinearities are considered, the effect is more complex. A comprehensive treatment is given for both degenerate and nondegenerate pump-probe experiments in noble and diatomic gases. Results of numerical calculations are compared to a recent transient birefringence measurement [Loriot et al., Opt. Express 17, 13429 (2009)] and a recent spectral interferometry experiment [Wahlstrand et al., Phys. Rev. A 85, 043820 (2012)]. We also present results from two new experiments using spectrally-resolved transient birefringence with 800 nm pulses in Ar and air and degenerate chirped pulse spectral interferometry in Ar. Both experiments support the interpretation of the negative birefringence at high intensity as arising from a plasma grating., Comment: 15 pages, 6 figures

Oral cancer is one of the most frequently diagnosed human cancers and leading causes of cancer death all over the world, but the prognosis and overall survival rate are still poor because of delay in diagnosis and lack of early intervention. The failure of early diagnosis is due to insufficiency of proper diagnostic and screening tools and most patients are reluctant to undergo biopsy. Optical virtual biopsy techniques, for imaging cells and tissues at microscopic details capable of differentiating benign from malignant lesions non-invasively, are thus highly desirable. A novel multi-harmonic generation microscope, excited by a 1260 nm Cr:forsterite laser, with second and third harmonic signals demonstrating collagen fiber distribution and cell morphology in a sub-micron resolution, was developed for clinical use. To achieve invivo observation inside the human oral cavity, a small objective probe with a suction capability was carefully designed for patients’ comfort and stability. By remotely changing its focus point, the same objective can image the mucosa surface with a low magnification, illuminated by side light-emitting diodes, with a charge-coupled device (CCD) for site location selection before the harmonic generation biopsy was applied. Furthermore, the slow galvanometer mirror and the fast resonant mirror provide a 30 fps frame rate for high-speed real-time observation and the z-motor of this system is triggered at the same rate to provide fast 3D scanning, again ensuring patients’ comfort. Focusing on the special cytological and morphological changes of the oral epithelial cells, our preliminary result disclosed excellent consistency with traditional histopathology studies.

Hyperglycemia is associated with advanced glycation end products (AGEs). Recently, AGEs were found to cause pancreatic damage, oxidative stress, and hyperglycemia through the AGE receptor. Carboxymethyllysine (CML) is an AGE but whether it induces pancreatic dysfunction remains unclear. Graptopetalum paraguayense, a vegetable consumed in Taiwan, has been used in folk medicine and is an antioxidant that protects against liver damage. We investigated the protective properties of G. paraguayense 95% ethanol extracts (GPEs) against CML-induced pancreatic damage. The results indicated that resveratrol, GPE, and gallic acid (the active compound of GPE) increased insulin synthesis via upregulation of pancreatic peroxisome proliferator activated-receptor-γ (PPARγ) and pancreatic-duodenal homeobox-1 (PDX-1) but inhibited the expression of CML-mediated CCAAT/enhancer binding protein-β (C/EBPβ), a negative regulator of insulin production. Moreover, resveratrol and GPE also strongly activated nuclear factor-erythroid 2-related factor 2 (Nrf2) to attenuate oxidative stress and improve insulin sensitivity in the liver and muscle of CML-injected C57BL/6 mice and resulted in reduced blood glucose levels. Taken together, these findings suggested that GPE and gallic acid could potentially be used as a food supplement to protect against pancreatic damage and the development of diabetes.

Femtosecond laser pulses filamenting in various gases are shown to generate long- lived quasi-stationary cylindrical depressions or ‘holes’ in the gas density. For our experimental conditions, these holes range up to several hundred microns in diameter with gas density depressions up to ~20%. The holes decay by thermal diffusion on millisecond timescales. We show that high repetition rate filamentation and supercontinuum generation can be strongly affected by these holes, which should also affect all other experiments employing intense high repetition rate laser pulses interacting with gases.

In this work, we investigated the principle of the two-photon absorption (TPA) detection with a loss modulation technique, and first demonstrated the existence of two-photon photoacoustics ultrasound excited by a femtosecond high repetition rate laser. By using the AO modulation with different modulation frequencies, we successfully create the beating of the light signal when the two arms of the beams are both spatial and temporal overlapping. The pulse train of the femtosecond laser causes the narrow band excitation, providing the frequency selectivity and sensitivity. Moreover, the pulse energy is no more than 15nJ/pulse, which is at least 3 orders of magnitude smaller than that of the nanosecond laser, and therefore prevents the thermal damage of the sample. With the help of lock-in detection and a low noise amplifier, we can separate the signal of two-photon absorption from one-photon absorption. We used an ultrasonic transducer to detect the response of the sample, and verified the existence of the two-photon photoacoustics ultrasound generating by the femtosecond laser. Several contrast agents, such as the black carbon solution, the fluorescence dye and the nano-particles, were used in the experiment. In the end, we demonstrated the application, two photo-acoustic imaging, which provides the high spatial resolution (

The nonlinear refractive index in air components and noble gases is measured absolutely using spectral interferometry in a thin gas target. Contributions from bound electronic states, molecular alignment, and free electrons from ionization are observed.

We show that femtosecond filaments produce mass density holes that decay over milliseconds in gases. Propagation of high repetition rate lasers is strongly affected, influencing the filament collapse point, supercontinuum generation, and pointing dynamics.

We investigate beam pointing dynamics in filamentation in gases driven by high repetition rate femtosecond laser pulses. Upon suddenly exposing a gas to a kilohertz train of filamenting pulses, the filament is steered from its original direction to a new stable direction whose equilibrium is determined by a balance among buoyant, viscous, and diffusive processes in the gas. Results are shown for Xe and air, but are broadly applicable to all configurations employing high repetition rate femtosecond laser propagation in gases., Comment: 6 pages, 4 figures

The nonlinear optical response to high fields is absolutely measured for the noble gas atoms He, Ne, Ar, Kr, and Xe. We find that the response is quadratic in the laser field magnitude up to the ionization threshold of each gas. Its size and quadratic dependence are well predicted by a Kramers-Kronig analysis employing known ionization probabilities, and the results are consistent with calculations using the time-dependent Schr\"odinger equation.