Intensity Ratio Values Research Articles

Study of the relationship of hydrogen bonding and hydrophobic interactions in W/O organogel emulsions by Raman microspectroscopy

The Raman technique can be used in the monitoring of molecular changes in organogel emulsions by intensity changes and band shifts. Raman spectra were obtained from individual components, then from an organogel and then from organogel emulsions. Raman bands corresponding to chemical bonds involved in intermolecular interactions were followed up. Changes Raman in mixture of lipophilic components were observed with respect to individual components and subsequently upon inclusion of an aqueous phase in emulsified systems. The organogel emulsions showed variations in Raman bands of hydrogen bonding and hydrophobic interactions. Variations in intensity ratio values of some bonds indicate modifications in the packing of the continuous phase that is affected by slight changes in surfactant concentration in time.

Atrial tissue characterization by cardiac magnetic resonance and high-density mapping in patients with atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Left atrial fibrosis is a marker of atrial disease and it has an important role in the pathophysiology of atrial fibrillation (AF). Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is an emerging tool to detect left atrial fibrosis. However, data on the correlation between LGE-CMR detected fibrosis and low voltage areas to define fibrotic tissue is scarce. PURPOSE To assess the correlation and degree of concordance between LGE-CMR and high-density bipolar voltage mapping for the identification of left atrial abnormal tissue. METHODS Seven patients scheduled for AF ablation (including first and redo procedures) underwent a preprocedural 1.5 Tesla LGE-CMR including left atrial 3D inversion-recovery steady-state free precession sequence (ECG and respiratory triggering) 20 minutes after the injection of 0.2 mmol/kg of gadobutrol. A high-density electroanatomical voltage mapping was acquired with a 16-electrode grid configuration mapping catheter during sinus rhythm. LGE-CMR studies were analyzed off-line with an advanced image post-processing tool (ADAS 3D). Atrial wall intensity was normalized to blood pool, obtaining an image intensity ratio (IIR) value for each CMR point of the 3D model. High-density bipolar voltage maps and LGE-CMR 3D left atrial reconstruction were merged (figure, panel A). Voltage points were projected to the LGE-CMR left atrial 3D model, allowing point-by-point correlation analysis between voltage (log transformed due to non-normal distribution) with IIR. Left atrial fibrosis area and percentage were quantified using the standard cut-off values (bipolar voltage <0.5mV and IIR >1.2). We assessed the degree of concordance for normal and abnormal (fibrosis) tissue classification between the two techniques using different cut-off values (< 0.5mV and <1mV for bipolar voltage and >0.9, >1, >1.1 and >1.2 for IIR). RESULTS The average fibrosis area detected with LGE-CMR was lower than that detected with high-density bipolar voltage, using standard cut-off values (18.6 ± 5.7 cm2 vs. 40.6 ± 12.5 cm2, p = 0.13 respectively). There was a poor global point-by-point correlation between log-transformed voltage and IIR was r=-0.093, p < 0.001 (figure, panel B). The best concordance was obtained when using bipolar voltage and IIR of 0.5mV and 1.2, respectively (64.7 %; Kappa 0.101). However, the highest kappa index (0.142) for concordance was achieved with cutoff values of bipolar voltage <1mV and IIR >1, with an agreement percentage of 54.6%. CONCLUSIONS Left atrial tissue characterization between LGE-CMR and high-density bipolar voltage mapping showed significant but poor point-by-point correlation. Although the highest concordance was obtained using standard cutoff values, the Kappa index was best when applying non-standard cutoffs (1mV for bipolar voltage and >1 for IIR). Abstract Figure.

Exploration of photophysical behavior of lanthanide complex and its hybrids

The present work envisioned to synthesize europium complexes [Eu-(L)3-phen] (where, L is 4,4,4-Trifluoro-1-(2-furyl)-1,3-butanedione (TFB), phen-1,10 -phenanthroline) and its hybrids via embedding pure complex into silica and PMMA. The sol–gel method was adopted for incorporating europium complex into silica matrix as [Eu-(L)3-phen]-silica and this method was proved to be highly effective and excellent approach for obtaining such lanthanide hybrid material. Another hybrid was prepared by incorporating complex into PMMA (polymethyl methyl acrylate), an organic polymer, transformed into flexible thin film. The structure of the [Eu-(L)3-phen] was elucidated using various spectroscopic techniques, moreover Sparkle model calculation were utilized for prediction of ground state geometry. The photophysical properties of pure complex [Eu-(L)3-phen] and its hybrids were studied in detail and compared. The incorporation of pure complex into PMMA is highly supportive to enhance the stability of complex as evident from enhanced luminescent intensity, intensity ratio value 6.52, longer lifetime value 842μs and higher quantum efficiency 77% over pure complex. The organic polymer PMMA is expected to interact well with europium complex via antenna effect. The use of such inorganic and organic entities for hybrid preparation purposefully overcomes the flaws of lanthanide complexes in terms of thermal stability and mechanical strength. The promising and fascinating properties of synthesized lanthanide hybrids are fruitful in material research.

Magnetic resonance imaging parameters in predicting the ablative efficiency of high-intensity focused ultrasound for uterine fibroids

Objective To evaluate the role of quantitative MRI parameters in predicting HIFU ablation results for uterine fibroids. Material and methods A total of 245 patients with uterine fibroids who underwent HIFU treatment in Chongqing Haifu Hospital were reviewed retrospectively. The patients were divided into two groups according to the non-perfused volume (NPV) ratio which was either higher or lower than 80%. The MRI parameters were measured, and a logistical regression analysis was performed to investigate the potential predictors associated with the NPV ratio. Receiver operating characteristics (ROC) analysis was used to determine the cut off value for MRI parameters in predicting a high NPV ratio. Results The subcutaneous fat thickness in the group of patients with an NPV ratio over 80% was significantly thinner than that in the group of patients with an NPV ratio less than 80% (15 mm versus 21 mm). The signal intensity ratio of fibroids to skeletal muscle on T2WI was significantly lower in the group of patients with an NPV ratio over 80% compared with the group with an NPV ratio lower than 80% (2.46 versus 3.23). The signal intensity ratio of fibroid to skeletal muscle correlated negatively with the NPV ratio and positively with the energy efficiency factor (EEF). The cut off value of signal intensity ratio of fibroid to muscle for predicting the NPV ratio over 80% is 3.045. Conclusion The signal intensity ratio of fibroid to skeletal muscle on T2WI can be used as a factor for predicting the effectiveness of HIFU ablation of uterine fibroids.

In-vivo Evaluation of Bleomycin-induced Lung Fibrosis Model Mouse Using Ultra High-field 7 T-MRI and Micro-CT

This study aimed to perform longitudinal observation using 4D-computed tomography (CT) and compare images acquired by 3D-CT and 3D-ultrashort echo time (UTE) for evaluation of bleomycin-induced lung fibrosis model. The pulmonary fibrosis model was induced by instilling intratracheally with 50 μl of bleomycin. 4D-CT images were classified into four phases after acquisition and analyzed. To study the effects of respiratory gating, we aquired 3D-CT and 3D-UTE images with and without respiratory gating. For comparison between CT and UTE images, we performed no-triggerd 3D-CT and 3D-UTE under free-breathing. MR signal intensity ratio and CT values were measured in three regions of the upper, middle, and lower lung. At 4DCT, total lung volume at maximum inspiration (4th phase) decreased significantly compared with control mouse and the ratio of lung volume at inspiration to expiration also showed a significant decrease. In comparison of the images between with and without respiratory gating, clearer images were obtained by respiratory gating. However, there was no significant difference between both. In comparison between CT and UTE images, magnetic resonance (MR) signal intensity ratio and CT value were significantly correlated, but 3D-UTE images showed poor delineation of the lower lung and that near the diaphragm compared with 3D-CT images. 4D micro-CT and nontriggered 3D UTE-magnetic resonance imaging (MRI) under free breathing can be useful to evaluate bleomycininduced lung fibrosis model mouse.

Relationship between epicardial fat and left atrium fibrosis in patients with atrial fibrillation

Abstract Background Epicardial adipose tissue (EAT) has recently been shown to be associated with the presence, severity, and recurrence of atrial fibrillation (AF). Although the pathophysiological mechanisms underlying this association remain to be established, several hypotheses have been put forward, including direct adipocyte infiltration, oxidative stress, and the secretion of adipokines causing inflammation and fibrosis of atrial tissue. We hypothesized that the volume of EAT and the amount of left atrium (LA) fibrosis assessed by non-invasive imaging would be significantly correlated in patients with AF, and that both would predict time to relapse after pulmonary vein isolation (PVI). Methods Sixty-eight patients with AF being studied for a first PVI procedure underwent both cardiac computerized tomography (CT) and cardiac magnetic resonance (CMR) within less than 48h. EAT was quantified on contrast-enhanced CT images. LA fibrosis was quantified on isotropic 1.5mm 3D delayed enhancement CMR for image intensity ratio values >1.20. Radiofrequency PVI was performed using an irrigated contact force-sensing ablation catheter, guided by electroanatomical mapping. After PVI, patients were followed for AF recurrence, defined as symptomatic or documented AF after a 3-month blanking period. Pearson's correlation coefficient was used for gauging the correlation between EATLM volume and LA fibrosis. The relationship between these two variables and time to AF recurrence was assessed by Cox regression. Results Most of the 68 patients (46 men, mean age 61±12 years) had paroxysmal AF (71%, n=48). The mean body mass index (BMI) was 28.0±4.0 kg/m2. Patients had a median EATLM volume of 2.4 cm3/m2 [interquartile range (IQR) 1.6–3.2 cm3/m2], and a median estimated amount of LA fibrosis of 8.9 g (IQR 5–15 g), corresponding to 8% (IQR 5–11%) of the total LA wall mass. The correlation between EATLM and LA fibrosis was statistically significant but weak (Pearson's R = 0.38, P=0.001) – Figure 1. During a median follow-up of 22 months (IQR 12–31), 31 patients (46%) suffered AF recurrence. Four predictors of relapse were identified in univariate Cox regression: EATLM (HR 2.19, 95% CI 1.65–2.91, P<0.001), LA fibrosis (HR 1.05, 95% CI 1.01–1.09, P=0.033), non-paroxysmal AF (HR 3.36, 95% CI 1.64–6.87, P=0.001), and LA volume (HR 1.03, 95% CI 1.01–1.06, P=0.006). Multivariate analysis yielded two independent predictors of time to AF relapse: EATLM (HR 2.05, 95% CI 1.51–2.79, P<0.001), and non-paroxysmal AF (HR 2.36, 95% CI 1.08–5.16, P=0.031). Conclusion The weak correlation between EAT and LA suggests that LA fibrosis is not the main mechanism by which EAT and AF are linked. EAT was more strongly associated with AF recurrence than LA fibrosis, which supports the existence of other, more important mediators between EAT and this arrhythmia. Correlation between EAT and LA Funding Acknowledgement Type of funding source: None

Influence of Oxide Glass Modifiers on the Structural and Spectroscopic Properties of Phosphate Glasses for Visible and Near-Infrared Photonic Applications.

The effect of oxide modifiers on multiple properties (structural and spectroscopic) of phosphate glasses with molar composition 60P2O5-(10−x)Ga2O3-30MO-xEu2O3 and 60P2O5-(10−y)Ga2O3-30MO-yEr2O3 (where M = Ca, Sr, Ba; x = 0, 0.5; y = 0, 1) were systematically examined and discussed. The local structure of systems was evidenced by the infrared (IR-ATR) and Raman spectroscopic techniques. The spectroscopic behaviors of the studied glass systems were determined based on analysis of recorded spectra (excitation and emission) as well as luminescence decay curves. Intense red and near-infrared emissions (1.5 μm) were observed for samples doped with Eu3+ and Er3+ ions, respectively. It was found that the value of fluorescence intensity ratio R/O related to 5D0→7F2 (red) and 5D0→7F1 (orange) transition of Eu3+ ions depends on the oxide modifiers MO in the glass host. However, no clear influence of glass modifiers on the luminescence linewidth (FWHM) was observed for phosphate systems doped with Er3+ ions. Moreover, the 5D0 and 4I13/2 luminescence lifetimes of Eu3+ and Er3+ ions increase with the increasing ionic radius of M2+ (M = Ca, Sr, Ba) in the host matrix. The obtained results suggest the applicability of the phosphate glasses with oxide modifiers as potential red and near-infrared photoluminescent materials in photonic devices.

A Numerical Investigation of the Minimum Ignition Energy Requirement for Forced Ignition of Turbulent Droplet-laden Mixtures

ABSTRACT The effects of droplet diameter, overall (i.e. liquid and gaseous phases) equivalence ratio, and turbulence intensity on the variation of the Minimum Ignition Energy (MIE) for localized forced ignition of uniformly dispersed mono-sized n-heptane droplet-laden mixtures under homogeneous isotropic decaying turbulence have been analyzed based on Direct Numerical Simulation (DNS) data. The MIE was evaluated just for (i) obtaining thermal runway irrespective of the fate of the resulting flame kernel, and (ii) also for a successful self-sustained flame propagation without the assistance of an external energy source following the energy deposition by the ignitor. It has been found that the MIE requirement increases with increasing turbulence intensity and this trend for the MIE increase is especially significant for large values of turbulence intensity. The MIE requirement increases with increasing initial droplet diameter and with decreasing overall equivalence ratio. The MIE requirements for droplet-laden mixtures have been found to be greater than the corresponding value for homogeneous mixture with the same nominal values of initial turbulence intensity and equivalence ratio for the parameter range considered here. This behavior arises due to the deposited energy being partially utilized to supply the latent heat of evaporation and also due to the predominantly fuel-lean composition of the gaseous flammable mixture. This tendency of obtaining fuel-lean mixture strengthens with increasing (decreasing) initial droplet diameter (overall equivalence ratio). It has also been demonstrated that combustion takes place predominantly in the fuel-lean premixed mode although there is a finite probability of having non-premixed combustion in all cases. Moreover, there is a small probability of fuel-rich combustion occurring for small droplets, especially under fuel-rich overall equivalence ratios. The stochastic nature of the ignition event has been demonstrated by considering different realizations of statistically similar turbulent flow fields. The conditions giving rise to a successful thermal runaway/self-sustained flame propagation have been identified by a detailed analysis of the energy budget.

Wind characteristics in the high-altitude difference at bridge site by wind tunnel tests

With the development of economy and construction technology, more and more bridges are built in complex mountainous areas. Accurate assessment of wind parameters is important in bridge construction at complex terrain. In order to investigate the wind characteristics in the high-altitude difference area, a complex mountain terrain model with the scale of 1:2000 was built. By using the method of wind tunnel tests, the study of wind characteristics including mean wind characteristics and turbulence characteristics was carried out. The results show: The wind direction is affected significant by the topography, the dominant wind direction is usually parallel to the river. Due to the sheltering effect of the mountain near the bridge, the wind speed and wind attack angle along the bridge are both uneven which is different from that at flat terrain. In addition, different from flat terrain, the wind attack angle is mostly negative. The wind profiles obey exponential law and logarithmic law. And the fitting coefficient is consistent with the code which means that it is feasible to use the method of wind tunnel test to simulate complex terrain. As for turbulence characteristics, the turbulence intensity is also related to the topography. Increases sheltering effect of mountain increases the degree of breaking up the large-scale vortices, thereby increasing the turbulence intensity. Also, the value of turbulence intensity ratio is different from the recommended values in the code. The conclusions of this study can provide basis for further wind resistance design of the bridge.

Effect of Uncarbonized and Carbonized Eggshell Powder on Mechanical and Thermal Properties of Recycled High Density Polyethylene/Ethylene Vinyl Acetate Blend Composites

The blend composites of recycled high density polyethylene (rHDPE)/ethylene vinyl acetate (EVA) were prepared by melt blending technique at 160 °C with rotor speed of 50 rpm within 10 minutes. Based on Fatimah et al. study[1], the optimum ratio rHDPE/EVA at 70/30 were studied and prepared for different loading of uncarbonized (fresh) and carbonized eggshell powder (5 to 25 wt%). The ESP was collected, washed, crushed, and sieved to obtained size 63 µm by method Farahana et al,.[2]. But she founded that, the mechanical properties reduced with incorporation of ESP filler. Nowadays, carbonized natural filler are the focus of some researchers and the CESP was undergoing a combustion process for 3 hours at 700 °C with air combustion via muffle furnace. The result showed tensile properties decreased with increasing filler loading for both fillers. Then, the mass swell percentage after 46 hours soaked in dichloromethane, the results showed an increment of both fillers were increased the mass swell caused by the hydrophilic nature of fillers. The intensity ratio, interlayer spacing, and crystallinity percentage value decrease with increasing filler loading for both filler give better interaction between matrix and filler. The thermal stability increase for both filler with increasing filler loading. Overall, rHDPE/EVA/CESP blend composites had excellent properties with the addition of carbonized filler.

Samarium complexes with fluorinated β-diketone and heterocyclic Lewis bases as UV light converters

Four new heteroleptic asymmetric fluorinated β-diketone based [Sm(fod)3] adducts with organic ligands of different denticities (monodentate indazole and triphenylphosphine oxide (tppo), bidentate imidazolyl pyridine (impy) and tridentate 2,4,6-tris(2-pyridyl)-s-triazine (tptz)) have been synthesized and characterized in order to examine the suitability of organic co-ligands as a sensitizer for Sm(III) luminescence. The photoluminescence of the complexes is studied in chloroform and solid state. The dominance of the hypersensitive transition 4G5/2 → 6H9/2 reflects the asymmetry around the Sm (III) ion in the present complexes which is supported by the large values of intensity ratio (RSm). The stark splitting in magnetic dipole 4G5/2 → 6H7/2 transition in the cases of eight coordinate [Sm(fod)3(impy)] (3) and [Sm(fod)3(tppo)2] (4) complexes is similar. However, the splitting pattern of 3 and 4 is distinctively different from the nine- [Sm(fod)3(tptz)] (1) and seven-coordinate [Sm(fod)3(indazole)] (2) complexes. The intensity of the hypersensitive transition and stark splitting of magnetic dipole transition changes significantly upon change in the ligand environment around the Sm (III). The bright luminescence from these complexes reflects efficient energy transfer from the selected sensitizers to Sm (III) ion. It is worth mentioning that the lifetime for 4G5/2 → 6H9/2 transition of complex 3 in solid state is 269 μs which is higher than the lifetime of this transition noted for most of the tris(β-diketonate)Sm(III) reported so for. The emission colour from chloroform solution of [Sm(fod)3(tppo)2] (4) changes from parrot green to orange red upon change in excitation wavelengths. Of the selected sensitizers, the impy is most efficient since the emission from its complex is most intense.

Er3+/Yb3+ co-doped TeO2–ZnO–ZnF2–La2O3 glass with a high fluorescence intensity ratio for an all-fiber temperature sensor

Er3+/Yb3+ co-doped TeO2–ZnO–ZnF2–La2O3 (TZZL) glasses with different concentrations of Er3+ ions were fabricated. Strong green upconversion emission bands centered at 523 and 545 nm induced by 980 nm excitation were observed. The maximum emission intensity of the TZZL glasses was obtained at the Er3+ ion concentration of 0.2 mol%. High-temperature difference (ΔT = 131.8 °C) between the transition and onset crystallization temperatures was confirmed by differential thermal analysis curve. The relationship between fluorescence intensity ratio value and temperature was examined within 303–560 K. The maximum absolute sensitivity (Sa) and the maximum relative sensitivity (Sr) was 0.006 K−1 at 560 K and 0.012 K−1 at 303 K, respectively. A prototype of an all-fiber temperature sensor was designed, and its temperature-sensing performance within 293–383 K was evaluated. Results showed that the absolute errors were within ±1 K, and the largest value of relative standard deviation was approximately 0.2%, suggesting that Er3+/Yb3+ co-doped TZZL glasses have potential applications in optical-fiber temperature sensors.

Prenatal assessment of fetal lung to liver signal intensity ratio using magnetic resonance imaging to predict neonatal respiratory outcome

Introduction: Fetal and maternal health problems lead to increase in incidence of preterm birth that has become a major concern in obstetric practice. Perinatal survival depends crucially on a sufficiently sized and a functionally developed cardiopulmonary system. So it is extremely important to diagnose lung maturity before birth because of the increase in the indications for early induction of labour. In these conditions, assessing the lung maturity will decide timing for inducing labour. Fetal MRI is a recently developing field that provides adequate information regarding the size, structure and biochemical maturity of developing Fetal lung that overcomes the adverse effects of amniocentesis. Therefore a ratio is considered for comparing the signal intensity of the Fetal lungs with that of another structure at a comparable depth. The ideal criteria for the reference structures are sufficient size, close proximity to the lung, homogeneity and stability through the pregnancy.Aim: Our aim was to establish a linear relationship between the estimated gestational age and the Lung- Liver Signal Intensity Ratio (LLSIR) values and to ultimately predict the lung maturity from this relationship.Materials and Methods: The patients for this study were selected from the antenatal outpatient department of a large medical college hospital in Chennai, India. The study population consisted of a total of 50 patients who were referred from the antenatal OPD for MRI for various other indications. The liver and lung images were taken in the same imaging plane for the analysis either in the coronal or sagittal view.Results: Magnetic resonance imaging of 50 cases were carried out during 19th and 40th week of gestationin antenatal women with age group from 23 to 31 years. LLSIR was calculated by taking the ratio of lung and liver signal intensity. The range of LLSIR is 1.54 to 4.03(2.808+0.739, mean+SD). There was no significant correlation between the liver intensity and EGA. The range of liver intensity was from 175 to 707 (425.08+115.22, mean+SD). The Pearson correlation coefficient between liver intensity and EGA was 0.232(p

Luminescence and self-referenced optical temperature sensing performance in Ca2YZr2Al3O12:Bi3+,Eu3+ phosphors

Ca2YZr2Al3O12:Bi3+,Eu3+ phosphors were elaborated by a traditional solid-state reaction method. The luminescence of Ca2YZr2Al3O12:Bi3+ samples, energy transfer from Bi3+ to Eu3+, and the temperature sensing properties of Ca2YZr2Al3O12:Bi3+,Eu3+ samples have been systematically researched. Under the excitation of ultraviolet light, Bi3+ single doped phosphors give 313 and 392 nm emission bands, which origin from the substitutions of Bi3+ instead of Ca2+ and Y3+ sites, respectively. And the color-adjustable emission from blue to red were observed by increasing Eu3+ content in Ca2YZr2Al3O12:Bi3+,Eu3+ samples. Relying on different temperature dependent variation tendency, the fluorescence intensity ratio (FIR) values present outstanding temperature sensing properties. The absolute and relative sensitivity can be up to 0.826 %K-1 and 0.664 %K-1, respectively. All above results suggest that Ca2YZr2Al3O12:Bi3+,Eu3+ phosphor is a potential alternative for optical thermometer.

Diffusion-weighted magnetic resonance imaging in bladder cancer: comparison of readout-segmented and single-shot EPI techniques

BackgroundTo evaluate whether readout-segment echo-planar imaging (RS-EPI) can provide better image quality in assessing bladder cancer than single-shot echo-planar imaging (SS-EPI) and to compare quantitative imaging parameters derived from both techniques.MethodsSeventy patients with bladder lesions were enrolled and underwent diffusion-weighted imaging on a 3 Tesla magnetic resonance scanner using axial RS-EPI and SS-EPI techniques. Two observers independently assessed the susceptibility, detectability, motion artefacts and blurring of the images using qualitative scores. The signal-to-noise ratio (SNR), signal intensity ratio (SIR), contrast-to-noise ratio (CNR) and ADC values of the bladder lesions were measured and compared between the two techniques and between two observers. Qualitative and quantitative comparisons of image quality were performed using the Wilcoxon signed-rank test and paired t-test. In addition, the agreement of the ADC measurements was evaluated using ICC values and Bland-Altman plots.ResultsSixty-eight patients were included in the final analysis. The scores of image susceptibility, detectability and blurring for RS-EPI were significantly higher than those for SS-EPI (all p < 0.05), while the motion artefact was not. There were significant differences between RS-EPI and SS-EPI in the CNR and SIR values (all p < 0.05) but not in the SNR or ADC values (all p > 0.05). The ICC values and Bland-Altman plots also showed excellent agreement between the measured ADC values of the bladder lesions.ConclusionsThe RS-EPI technique provides significantly better image quality in patients with bladder cancer than the SS-EPI technique, without a significant difference in the ADC value.

Temporal behaviour of bright solitons in photorefractive crystals having both the linear and quadratic electro-optic effect

Abstract We investigate the characteristics of formation or time evolution of optical spatial solitons in novel photorefractive media having both the linear and quadratic electro-optic effect. We have derived a one dimensional time dependant wave propagation equation in biased photorefractive media having both the linear and quadratic electro-optic effect. The variation of soliton width with time is investigated for different values of peak intensity ratio and it is shown that these bright solitons can exist both in the quasi steady state and steady state regimes for high saturation values. Two distinct regimes of intensity ratio are identified where the soliton formation characteristics are different. Only steady state solitons are formed if the intensity ratio is small. Soliton characteristics like the initial soliton width, steady state soliton width, and quasi steady state soliton width are investigated for both regimes and found to depend on as varying functions of the intensity ratio. We also find that the individual magnitudes of the linear and quadratic electro-optic coefficients affect the temporal characteristics of formation of the solitons. Appropriate example has been taken for an illustration of our results.

Red-emitting phosphor series: Ca9Y(PO4)7(1-x)(VO4)7x:Eu3+ (x = 0 − 1) with improved luminescence thermal stability by anionic polyhedron substitution

Superior thermal stability of the phosphors is crucial to retain the light balance of phosphor-converted WLEDs. At present, the fundamental research on the development of the phosphors with high thermal stability remains a challenging task. In this work, a series of red-emitting phosphors Ca9Y(PO4)7(1−x)(VO4)7x:Eu3+ (x = 0 − 1), in which phosphate groups were gradually replaced by vanadate groups, were synthesized via a high temperature solid-state reaction method. Their XRD patterns, Raman spectra, photoluminescent excitation and emission spectra, as well as temperature dependent emission properties and decay curves were investigated. The results of XRD pattern and Raman spectra indicated that a solid solution formed in Ca9Y(PO4)7(1−x)(VO4)7x:Eu3+ from x = 0 to x = 1. The photoluminescent properties study revealed that emission intensity upon the excitation 393 nm decreased while that under the irradiation of 464 nm increased with the improvement of vanadate groups. Moreover, the substitution of vanadium ions can increase the red to orange intensity ratio values of Eu3+. Especially, a limited amount of vanadium in Ca9Y(PO4)7:Eu3+ will improve the luminescence thermal stability. This was confirmed by temperature dependent lifetime values for the phosphors with and without vanadium. The possible reason affecting the above properties have been considered in details.

Dy3+ doped tellurite glasses for solid-state lighting: An investigation through physical, thermal, structural and optical spectroscopy studies

In the present work, a series of Dy3+ ion doped tellurite glasses in the (50-x)TeO2-25WO3-25Li2O-xDy2O3 system were synthesized using conventional melt quenching technique to investigate colorimetric and radiative properties of Dy3+ ions in a new and stable host for their evaluation as solid-state lighting materials. Physical and structural properties were studied through density calculations, refractive index measurements, and Fourier-transform IR spectroscopy analysis. Thermal properties of glasses – glass transition (Tg) and crystallization (Tc/Tp) temperatures and temperature difference (ΔT) – were determined using differential scanning calorimetry. Optical absorption spectra of glasses were recorded with Vis-NIR spectrophotometer. CIE color coordinates, correlated color temperature, color rendering index and yellow to blue emission intensity ratio values were obtained through photoluminescence analysis. Radiative properties such as, radiative transition probability, stimulated emission cross-section, branching ratio and optical bandwidth gain were calculated according to Judd-Ofelt theory. The obtained optical spectroscopy results were found to be comparable or better than other reported glass systems. From the derived results, glasses with Dy3+ ion concentration lower than 0.5 mol% were found to show the closest CIE color coordinate values to pure white light and highest CCT and CRI values revealing good potentiality to be used for applications in white LEDs and solid-state lasers.

Improvement of the O2 detection: Substituent’s effect on Pd(II) meso-tetraphenylporphyrin probes

Luminescence-based sensors are among the most promising tools for detection of oxygen gas.Improving the performance of such sensors is still an issue that requires an optimization of its composition which includes an oxygen sensitive probe embedded in a polymeric matrix with or without additives. Our approach is based on design of oxygen sensitive probes and aims at understanding the relationship between the structural variation of the probe and its oxygen sensing ability. In this context, our choice focuses on a non-symmetric palladium meso-tetraphenylporphyrin bearing three electron donor hexyloxy (-OC6H13) and one electron withdrawing phenylacetylide substituents (3-Pd). Poly (trimethylsilyl propyne) [poly(TMSP)] was privileged as polymeric matrix material due to is high oxygen permeability, also silver nanoparticles (AgNPs) were added to magnify the sensor sensitivity. The AgNP supported 3-Pd-doped poly(TMSP) microfiber [AgNP-(3-Pd)MF] in its optimal composition shows an exceptional intensity ratio value I0/I100 = 335, a high Stern-Volmer constant (KSV = 6.4274%−1), a short response time (2 s), and quite low limit of detection (4.66 × 10-4 %−1).

Discovery of lipid biomarkers correlated with disease progression in clear cell renal cell carcinoma using desorption electrospray ionization imaging mass spectrometry.

Clear cell renal cell carcinoma (ccRCC) often results in recurrence or metastasis, and there are only a few clinically effective biomarkers for early diagnosis and personalized therapy. Metabolic changes have been widely studied using mass spectrometry (MS) of tissue lysates to identify novel biomarkers. Our objective was to identify lipid biomarkers that can predict disease progression in ccRCC by a tissue-based approach. We retrospectively investigated lipid molecules in cancerous tissues and normal renal cortex tissues obtained from patients with ccRCC (n = 47) using desorption electrospray ionization imaging mass spectrometry (DESI-IMS). We selected eight candidate lipid biomarkers showing higher signal intensity in cancerous than in normal tissues, with a clear distinction of the tissue type based on the images. Of these candidates, low maximum intensity ratio (cancerous/normal) values of ions of oleic acid, m/z 389.2, and 391.3 significantly correlated with shorter progression-free survival compared with high maximum intensity ratio values (P = 0.011, P = 0.022, and P < 0.001, respectively). This study identified novel lipid molecules contributing to the prediction of disease progression in ccRCC using DESI-IMS. Our findings on lipid storage may provide a new diagnostic or therapeutic strategy for targeting cancer cell metabolism.