Changes In Relative Intensities Research Articles

Electrical and optical characteristics of the radio frequency surface dielectric barrier discharge plasma actuation**Project supported by the National Natural Science Foundation of China (Grant Nos. 11472306, 51276197, and 51336011).

Electrical characteristics and optical emission spectrum of the radio frequency (RF) surface dielectric barrier discharge (SDBD) plasma actuation are investigated experimentally in this paper. Influences of operating pressure, duty cycle and load power on the discharge are analyzed. When the operating pressure reaches 30 kPa, the discharge energy calculated from the Charge–Voltage (Q–V) Lissajous figure increases significantly, while the effective capacitance decreases remarkably. As the duty cycle of the applied voltage increases, the voltage–current waveforms, the area of Q–V loop and the capacity show no distinct changes. Below 40 W, effective capacitance increases with the increase of load power, but it almost remains unchanged when load power is between 40 W and 95 W. The relative intensity changes little as the operating pressure varies from 4 kPa to 100 kPa, while it rises evidently with the pressure below 4 kPa, which indicates that the RF discharge mode shifts from filamentary discharge to glow discharge at around 4 kPa. With the increase of load power, the relative intensity rises evidently. Additionally, the relative intensity is insensitive to the pressure, the duty cycle, and the load power.

The crystallographic template effect assisting the formation of stable α-Al2O3 during low temperature oxidation of Fe–Al alloys

The role of thermally grown α-Fe2O3 on the nucleation of α-Al2O3 during oxidation of binary Fe–Al alloys with 15 and 26 at.%Al at 700°C was investigated. Surface morphology of the oxide scales indicated direct nucleation of α-Al2O3 preferentially instead of conversion from metastable Al2O3 polymorphs. Oxide scale development over time was also monitored by use of synchrotron X-ray diffraction and Raman spectroscopy. The results showed that the α-Fe2O3 crystal lattice decreases in volume as oxidation progresses, which was found to be consistent with an Al3+ enrichment of α-Fe2O3 as confirmed by the change in relative intensity of α-Fe2O3 Raman peaks.

Investigation of the Structural, Optical and Electrical Properties of Gadolinium-Doped Zinc Oxide Films Prepared by Sol-Gel Method

Thin films of undoped and gadolinium-doped zinc oxide (Gd-doped ZnO) with different Gd concentration (1-8 at. %) were deposited onto a glass substrate by sol–gel spin-coating technique. X-ray diffraction (XRD, Bruker D8 Advance) studies confirmed the nature of the films as polycrystalline, with typical hexagonal wurtzite structure. The film also showed variation in crystallite size and change in relative intensities, upon different Gd concentrations. Besides, the influence of Gd concentration on the optical transmittance of ZnO films was studied using ultraviolet-visible spectrophotometer (UV-Vis, Shimadzu UV 1800) in the wavelength range 300-800 nm. The optical transmittance of all films is higher than ~95% in the visible region, and doped films become more transparent. The electrical resistance was measured by two point probe (Keithley-2400). The resistance decrease with increasing Gd concentration up to 2 at.% and it increased for further increase Gd concentrations.

Corporate Financing Decisions and Investment Inefficiency

Ponte Academic JournalApr 2016, Volume 72, Issue 4 Corporate Financing Decisions and Investment InefficiencyAuthor(s): Hsiao-Fen HsiaoJ. Ponte - Apr 2016 - Volume 72 - Issue 4 doi: 10.21506/j.ponte.2016.4.31 Abstract:We set out in this study to examine the relationship between the financing decisions of firms and level of inefficient investment. We demonstrate that firms with (non-)valuable investment opportunities, the actual level of investment invariably tends to less (more) than the optimal level which problem of under-investment (over-investment). We carry out two types of empirical tests, analyzing the level of investment for maximum firm value (dependent upon the quality of the investment opportunities) so as to gauge the relative magnitude of the investment inefficiencies effects. Firstly, from an examination of the relative changes in the investment intensity of firms following financing decisions, we find that those firms issuing equity or dual tend to under-investment, and that this is largely dependent upon the valuable investment opportunities available to them. Secondly, we examine different financing decisions in an attempt to determine whether such decisions represent the underlying cause of such inefficient investment. Download full text:Check if you have access through your login credentials or your institution Username Password

High pressure Raman investigations on crystalline crotonic acid

Abstract In-situ high pressure Raman spectra of crotonic acid have been measured up to 14 GPa, a possible solid–solid phase transition was detected at about 6 GPa from the frequency–pressure relationship. According to the relative intensity changes of typical Raman peaks, the inter-molecular hydrogen bond interactions, as well as molecular structural transformation are concluded. Compared to the linear frequency–pressure relationships, an exponential intensity–pressure relationship was concluded, which was sensitive to inter-molecular interactions under external compression.

Fluorescence Lifetime Imaging of Apoptosis.

Genetically encoded fluorescence resonance energy transfer (FRET) reporters are powerful tools for analyzing cell signaling and function at single-cell resolution in standard 2D cell cultures, but these reporters rarely have been applied to 3D environments. FRET interactions between donor and acceptor molecules typically are determined by changes in relative fluorescence intensities, but wavelength-dependent differences in light absorption complicate this analysis method in 3D settings. Herein we report fluorescence lifetime imaging microscopy (FLIM) with phasor analysis, a method that displays fluorescence lifetimes on a pixel-wise basis in real time to quantify apoptosis in breast cancer cells stably expressing a genetically encoded FRET reporter. This microscopic imaging technology allowed us to identify treatment-induced apoptosis in single breast cancer cells in environments ranging from 2D cell culture, spheroids with cancer and bone marrow stromal cells, and living mice with orthotopic human breast cancer xenografts. Using this imaging strategy, we showed that combined metabolic therapy targeting glycolysis and glutamine pathways significantly reduced overall breast cancer metabolism and induced apoptosis. We also determined that distinct subpopulations of bone marrow stromal cells control the resistance of breast cancer cells to chemotherapy, suggesting heterogeneity of treatment responses of malignant cells in different bone marrow niches. Overall, this study establishes FLIM with phasor analysis as an imaging tool for apoptosis in cell-based assays and living mice, enabling real-time, cellular-level assessment of treatment efficacy and heterogeneity.

Baseline Correction of Diffuse Reflection Near-Infrared Spectra Using Searching Region Standard Normal Variate (SRSNV).

An alternative baseline correction method for diffuse reflection near-infrared (NIR) spectra, searching region standard normal variate (SRSNV), was proposed. Standard normal variate (SNV) is an effective pretreatment method for baseline correction of diffuse reflection NIR spectra of powder and granular samples; however, its baseline correction performance depends on the NIR region used for SNV calculation. To search for an optimal NIR region for baseline correction using SNV, SRSNV employs moving window partial least squares regression (MWPLSR), and an optimal NIR region is identified based on the root mean square error (RMSE) of cross-validation of the partial least squares regression (PLSR) models with the first latent variable (LV). The performance of SRSNV was evaluated using diffuse reflection NIR spectra of mixture samples consisting of wheat flour and granular glucose (0-100% glucose at 5% intervals). From the obtained NIR spectra of the mixture in the 10 000-4000 cm(-1) region at 4 cm intervals (1501 spectral channels), a series of spectral windows consisting of 80 spectral channels was constructed, and then SNV spectra were calculated for each spectral window. Using these SNV spectra, a series of PLSR models with the first LV for glucose concentration was built. A plot of RMSE versus the spectral window position obtained using the PLSR models revealed that the 8680–8364 cm(-1) region was optimal for baseline correction using SNV. In the SNV spectra calculated using the 8680–8364 cm(-1) region (SRSNV spectra), a remarkable relative intensity change between a band due to wheat flour at 8500 cm(-1) and that due to glucose at 8364 cm(-1) was observed owing to successful baseline correction using SNV. A PLSR model with the first LV based on the SRSNV spectra yielded a determination coefficient (R2) of 0.999 and an RMSE of 0.70%, while a PLSR model with three LVs based on SNV spectra calculated in the full spectral region gave an R2 of 0.995 and an RMSE of 2.29%. Additional evaluation of SRSNV was carried out using diffuse reflection NIR spectra of marzipan and corn samples, and PLSR models based on SRSNV spectra showed good prediction results. These evaluation results indicate that SRSNV is effective in baseline correction of diffuse reflection NIR spectra and provides regression models with good prediction accuracy.

Miniature Flow-Through Low-Temperature Plasma Ionization Source for Ambient Ionization of Gases and Aerosols.

The design and operation of an inexpensive, miniature low-temperature plasma ion source is detailed. The miniature low-temperature plasma ion source is operated in a "flow-through" configuration, wherein the gaseous or aerosolized analyte, caffeine or pyrolyzed ethyl cellulose, in a carrier gas is used as the plasma gas. In this flow-through configuration, the sensitivity for the caffeine standard and the pyrolysis products of ethyl cellulose is maintained or increased and the reproducibility of the ion source is increased. Changes in the relative intensity of ions from the aerosol produced by pyrolysis of ethyl cellulose are observed in the mass spectrum when the low-temperature plasma ion source is used in the flow-through configuration. Experiments suggest this change in relative intensity is likely due to differences in ionization efficiency rather than increased fragmentation of ethyl cellulose pyrolysis products during ionization. Flow-through low-temperature plasma ionization with the miniature ion source is shown to be a promising technique for the ionization of compounds in gases or aerosol particles.

Study Behavior of XPS Spectra of Ni, Mn, Y and O in Y2NiMnO6 Ceramics

Bulk Y2NiMnO6 samples were prepared by thermal decomposition technique at 800 °C for 6 hours. The effects of temperature on the structure of ceramics were investigated for different sintering temperatures in the range of 1000-1300 °C, while kept constant the sintering time of 12 hours. Structural characterization had been investigated via X-ray diffraction (XRD) on samples of different sintering temperatures. Results from the experiment had revealed that high temperature affected oxide in ceramic materials. Further analysis with X-ray photoelectron spectroscopy (XPS) technique had revealed an outstanding point of ceramics by investigating the Ni 2p, 2p3/2, Mn 2p1/2, 2p3/2, and Y 3d3/2, 3d5/2 at the surface of Y2NiMnO6 ceramics. The changes in relative intensity of XPS peaks and the shifts in their binding energy (eV) were observed in the results, while the effect of temperature on oxide in ceramics may be investigated with dielectric property in the future.

Conformational analysis of morpholine studied using Raman spectroscopy and density functional theoretical calculations

Morpholine is a very interesting cyclic compound which is an ether as well as a secondary amine. The relative distribution of different conformations of morpholine depends on the medium. Using Raman spectroscopy and theoretical calculations, we found that, equatorial chair conformer is predominant in the pure liquid, but in aqueous solution, contribution from the axial conformer increases. The surface-enhanced Raman scattering (SERS) studies in presence of silver nanoparticles showed change in relative intensities of different vibrational modes of morpholine. It was found that the axial chair conformer is preferentially adsorbed vertically through the NAg bond on the nanoparticle surface.

Monitoring As and Hg variation in An-Gong-Niu-Huang Wan (AGNH) intermediates in a pilot scale blending process using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was used to assess the cinnabar and realgar blending of An-Gong-Niu-Huang Wan (AGNH) in a pilot-scale experiment, including the blending end-point. The blending variability of two mineral medicines, cinnabar and realgar, were measured by signal relative intensity changing rate (RICR) and moving window standard deviation (MWSD) based on LIBS. Meanwhile, relative concentration changing rate (RCCR) was obtained based on the reference method involving inductively coupled plasma optical emission spectrometry (ICP-OES). The LIBS result was consistent with ICP-OES at blending end-point determinations of both mineral medicines. Unlike the ICP-OES method, LIBS does not have an elaborate digestion procedure. LIBS is a promising and rapid technique to understand the blending process of Chinese Materia Medica (CMM) containing cinnabar and realgar. These results demonstrate the potential of LIBS in monitoring CMM pharmaceutical production.

Automated Quantification of Tumor Viability in a Rabbit Liver Tumor Model after Chemoembolization Using Infrared Imaging

The rabbit VX2 tumor is a fast-growing carcinoma model commonly used to study new therapeutic devices, such as catheter-based therapies for patients with inoperable hepatocellular carcinoma. The evaluation of tumor viability after such locoregional therapies is essential to directing hepatocellular carcinoma management. We used infrared microspectroscopy for the automatic characterization and quantification of the VX2 liver tumor viability after drug-eluting beads transarterial chemoembolization (DEB-TACE). The protocol consisted of K-means clustering followed by principal component analysis (PCA) and linear discriminant analysis (LDA). The K-means clustering was used to classify the spectra from the infrared images of control or treated tumors and to build a database of many tissue spectra. On the basis of this reference library, the PCA-LDA analysis was used to build a predictive model to identify and quantify automatically tumor viability on unknown tissue sections. For the DEB group, the LDA model determined that the surface of tumor necrosis represented 91.6% ± 8.9% (control group: 33.1% ± 19.6%; Mann-Whitney P = 0.0004) and the viable tumor 2.6% ± 4% (control group: 62.2% ± 15.2%; Mann-Whitney P = 0.0004). Tissue quantification measurements correlated well with tumor necrosis (r = 0.827, P < 0.0001) and viable tumor (r = 0.840, P < 0.0001). Infrared imaging and PCA-LDA analysis could be helpful for easily assessing tumor viability.

A highly tunable and fully biocompatible silk nanoplasmonic optical sensor.

Novel concepts for manipulating plasmonic resonances and the biocompatibility of plasmonic devices offer great potential in versatile applications involving real-time and in vivo monitoring of analytes with high sensitivity in biomedical and biological research. Here we report a biocompatible and highly tunable plasmonic bio/chemical sensor consisting of a natural silk protein and a gold nanostructure. Our silk plasmonic absorber sensor (SPAS) takes advantage of the strong local field enhancement in the metal-insulator-metal resonator in which silk protein is used as an insulating spacer and substrate. The silk insulating spacer has hydrogel properties and therefore exhibits a controllable swelling when exposed to water-alcohol mixtures. We experimentally and numerically show that drastic spectral shifts in reflectance minima arise from the changing physical volume and refractive index of the silk spacer during swelling. Furthermore, we apply this SPAS device as a glucose sensor with a very high sensitivity of 1200 nm/RIU (refractive index units) and high relative intensity change.

Do Train‐or‐Pay Schemes Really Increase Training Levels?

Reacting to perceived market failures leading to under‐optimal levels of firm‐sponsored training, governments all over the world have stepped in with various policy instruments to alleviate this problem, using incentives such as regulation or co‐financed schemes directed at firms or at individuals. Despite the widespread use of these schemes, rigorous empirical evaluation of such policies is uncommon. In this paper, we provide a careful evaluation of a reform in a train‐or‐pay scheme used in Canada that exempted medium‐sized workplace from the training requirement. Our identification strategy involves comparing changes in training levels in medium‐sized workplaces, before and after the reform, to changes for both smaller and larger workplaces. We also compare relative changes in training intensities to those observed in a neighboring province in which no such changes took place. We find the policy had no impact on training levels but caused firms to change their human capital investments portfolio, substituting informal and formal training.

Crystal structure and photoluminescence of (Gd,Ce)4(SiS4)3 and (Y,Ce)4(SiS4)3

Structural and photoluminescence (PL) properties of undoped and Ce3+-doped rare-earth thiosilicate (Gd1-xCex)4(SiS4)3 () and (Y1-xCex)4(SiS4)3 () are reported. They maintain a monoclinic structure (P21/n) for the whole range of x. Increases in lattice constants appear with the increase in x because of the replacement of Gd3+ and Y3+ by larger Ce3+. Yellow-orange PL originating from the 5d1-4f1 (2FJ, ) transition of Ce3+ is obtained. From the measurement of PL spectra at 20 K, red shifts of the peak wavelength with the increase in x would be understood by the change of relative intensity for two luminescent centers of Ce3+ in PL bands. The maximum internal quantum efficiency is 62% for (YCe)4(SiS4)3. These phosphors have higher water-resistance than alkaline-earth metal thiosilicate phosphors such as Ba2SiS4.

On the spatial distribution of the reflection sources of different latency components of otoacoustic emissions.

The experimental observation of long- and short-latency components in both stimulus-frequency and transient-evoked otoacoustic emissions admits a comprehensive explanation within the coherent reflection mechanism, in a linear active transmission-line cochlear model. A local complex reflectivity function associated with roughness was defined and analyzed by varying the tuning factor of the model, systematically showing, for each frequency, a multiple-peak spatial structure, compatible with the observed multiple-latency structure of otoacoustic emissions. Although this spatial pattern and the peak relative intensity changes with the chosen random roughness function, the multiple-peak structure is a reproducible feature of different "digital ears," in good agreement with experimental data. If one computes the predicted transmission delays as a function of frequency and position for each source, one gets a good match to the latency-frequency patterns that are directly computed from synthesized otoacoustic spectra using time-frequency analysis. This result clarifies the role of the spatial distribution of the otoacoustic emission sources, further supporting the interpretation of different-latency otoacoustic components as due to reflection sources localized at different places along the basilar membrane.

Selective fluorescence sensing of salicylic acids using a simple pyrenesulfonamide receptor

The highest change in relative intensity of probe 3 among the probes 2–5 with 3,5-DNSA demonstrated the significance of sulfonamide N–H and imidazole C2–H with the highest association constant and complete quenching.

Spectroscopic Investigations of &amp;lt;i&amp;gt;β&amp;lt;/i&amp;gt;-Amyloid Interactions with Propofol and L-Arginine

Beta amyloid (Aβ) aggregation has been characterized to be responsible for several amyloid diseases. Fourier transform infrared (FTIR) spectroscopy, fluorescence, and atomic force microscopy (AFM) are used to investigate induced changes in the secondary structure of Aβ upon thermal denaturation and interaction with propofol and L-arginine. Spectral analysis has revealed an effective static quenching for the intrinsic fluorescence of Aβ by propofol and l-arginine with binding constants of 2.81 × 102 M-1 for Aβ-propofol and 0.37 × 102 M-1 for Aβ-L-arginine. Fourier self-deconvolution (FSD) technique has been used to evaluate the relative intensity changes in the spectra of the component bands in the amide I and amide II regions at different ligand’s concentration in the protein complex. The analysis showed a decrease in the intensities of the parallel beta bands of propofol and L-arginine interactions with Aβ, accompanied with an increase in the antiparallel bands for the Aβ-propofol interaction and a decrease for the Aβ-l-arginine interaction. The relative increase in peaks’ intensities at 1694 cm-1 and 1531 cm-1 for the propofol interaction is linked to the formation of oligomers in the protein.

Decadal‐scale variations in geomagnetic field intensity from ancient Cypriot slag mounds

AbstractGeomagnetic models based on direct observations since the 1830s show that the averaged relative change in field intensity on Earth's surface over the past 170 years is less than 4.8% per decade. It is unknown if these rates represent the typical behavior of secular variations due to insufficient temporal resolution of archaeomagnetic records from earlier periods. To address this question, we investigate two ancient slag mounds in Cyprus—Skouriotissa Vouppes (SU1, fourth to fifth centuries CE, 21 m in height), and Mitsero Kokkinoyia (MK1, seventh to fifth centuries BCE, 8 m in height). The mounds are multilayered sequences of slag and charcoals that accumulated near ancient copper production sites. We modeled the age‐height relation of the mounds using radiocarbon dates, and estimated paleointensities using Thellier‐type IZZI experiments with additional anisotropy, cooling rate, and nonlinear TRM assessments. To screen out ambiguous paleointensity interpretations, we applied strict selection criteria at the specimen/sample levels. To ensure objectivity, consistency, and robust error estimation, we employed an automatic interpretation technique and put the data available in the MagIC database. The analyses yielded two independent subcentury‐scale paleointensity time series. The MK1 data indicate relatively stable field at the time the mound accumulated. In contrast, the SU1 data demonstrate changes that are comparable in magnitude to the fastest changes inferred from geomagnetic models. We suggest that fast changes observed in the published archaeomagnetic data from the Levant are driven by two longitudinally paired regions, the Middle East and South Africa, that show unusual activity in geomagnetic models.

SERS Characterization of the Indocyanine-Type Dye IR-820 on Gold and Silver Nanoparticles in the Near Infrared

The Raman spectrum of the indocyanine-type dye IR-820 has been assigned for both solid and solution. SERS spectra of IR-820 on both silver and gold nanoparticles suspensions excited at 1064 nm were obtained. AgNPs allowed the detection of the dye through SERS down to 0.1 micromoles per liter; for the AuNPs the lowest concentration of the dye detectable was 10 micromoles per liter. Changes in the SERS relative intensities compared to the Raman spectrum in solution are subtle, mostly due to the preresonance effect of the dye. However, a perpendicular orientation relative to the metallic surface was inferred for the dye on both AgNPs and AuNPs. The easily distinguishable SERS spectra of the dye excited at 1064 nm, together with the high biological compatibility of cyanine dyes, are both indicative that IR-820 could be used as a high-performance probe molecule for SERS.