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•InP-In2O3 QDs are synthesized by a single-step chemical method without injection of hot precursors.•HR-TEM images show the synthesis of InP and In2O3 QDs.•The InP and In2O3 QDs size ...increases with the P(TMS)3 concentration.•PL spectra reveal emission bands attributed to InP and In2O3 QDs.•XPS confirms the formation of InP, In2O3 and amorphous InPOx.
InP-In2O3 colloidal quantum dots (QDs) synthesized by a single-step chemical method without injection of hot precursors (one-pot) were investigated. Specifically, the effect of the tris(trimethylsilyl)phosphine, P(TMS)3, precursor concentration on the QDs properties was studied to effectively control the size and shape of the samples with a minimum size dispersion. The effect of the P(TMS)3 precursor concentration on the optical, structural, chemical surface, and electronic properties of InP-In2O3 QDs is discussed. The absorption spectra of InP-In2O3 colloids, obtained by both UV–Vis spectrophotometry and photoacoustic spectroscopy, showed a red-shift in the high-energy regime as the concentration of the P(TMS)3 increased. In addition, these results were used to determine the band-gap energy of the InP-In2O3 nanoparticles, which changed between 2.0 and 2.9 eV. This was confirmed by Photoluminescence spectroscopy, where a broad-band emission displayed from 2.0 to 2.9 eV is associated with the excitonic transition of the InP and In2O3 QDs. In2O3 and InP QDs with diameters ranging approximately from 8 to 10 nm and 6 to 9 nm were respectively found by HR-TEM. The formation of the InP and In2O3 phases was confirmed by X-ray Photoelectron Spectroscopy.
In0.145Ga0.855AsySb1−y semiconductor alloys were grown on GaSb(100) substrates by varying the As content by liquid phase epitaxy (LPE). We demonstrated that the growth mechanism of these quaternary ...alloys is mainly constituted by two stable bonding configurations, Ga−Sb and In−As. These quaternary alloys showed a high crystalline quality due to the nearly lattice-matched epitaxial growth to the GaSb substrate. We identified a tensile strain of the In0.145Ga0.855AsySb1−y alloys on the GaSb substrate, strain that increases with the As content. In the bulk region of these crystalline alloys it was noticed a greater fonon-plasmon coupling than in the surface space-charge region. In addition, we found that the band gap energy of the In0.145Ga0.855AsySb1−y alloys can be easily engineered in the near infrared by varying the As content. Excitonic transitions were observed in these quaternary alloys, whose energy decreases with the As content. We employed a theoretical method that considers spin-orbit coupling for the determination of the band gap energy, which is in agreement with experimental results. These findings provide an important understanding of the growth dynamics, and of the optical and structural properties of the In0.145Ga0.855AsySb1−y crystalline alloys by varying the As content for near infrared applications using the band gap engineering.
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•In0.145Ga0.855AsySb1−y alloys were grown on GaSb substrate by varying the As content.•The quaternary alloys were grown by Liquid Phase Epitaxy (LPE).•The growth mechanism of these alloys is mainly constituted by Ga−Sb and In−As.•The excitonic transition energies of the alloys decrease with the As content.
Our purpose is to adapt a statistical method for the analysis of discrete numerical series to the keywords appearing in scientific articles of a given area. As an example, we apply our methodological ...approach to the study of the keywords in the Library and Information Sciences (LIS) area. Our objective is to detect the new author keywords that appear in a fixed knowledge area in the period of 1 year in order to quantify the probabilities of survival for 10 years as a function of the impact of the journals where they appeared. Many of the new keywords appearing in the LIS field are ephemeral. Actually, more than half are never used again. In general, the terms most commonly used in the LIS area come from other areas. The average survival time of these keywords is approximately 3 years, being slightly higher in the case of words that were published in journals classified in the second quartile of the area. We believe that measuring the appearance and disappearance of terms will allow understanding some relevant aspects of the evolution of a discipline, providing in this way a new bibliometric approach.
In
x
Ga
1
-
x
As
y
Sb
1
-
y
epilayers with a fixed In content of
x
= 0.145 were grown on GaSb(100) substrates using liquid-phase epitaxy (LPE). The lattice mismatch between the quaternary epilayers ...and substrates was analyzed for different As contents (
y
) by X-ray
ω
-2
θ
. Epilayers with As content between
y
= 0.120 and
y
= 0.124 exhibited a positive lattice mismatch, leading to compressive strain. These samples showed a high crystalline quality and flat surfaces, as confirmed by high-resolution X-ray diffraction (HR-XRD) and atomic force microscopy (AFM). Quaternary alloys with As content between
y
= 0.133 and
y
= 0.141 displayed a negative lattice mismatch, resulting in tensile strain. Structural defects in these samples were evidenced by HR-XRD and on AFM micrographs. Raman measurements also revealed that lateral strain has a direct impact on the intensities of the LO-like, phonon–plasmon and disorder-activated longitudinal acoustic modes. For all In
x
Ga
1
-
x
As
y
Sb
1
-
y
films, photoluminescence (PL) spectra showed a bound exciton (BE) transition, with additional features observed in samples under tensile strain, indicating the involvement of native defect centers and donor–acceptor pairs. This study provides new insights into the effect of lateral strain on the crystalline and surface quality, and optical properties of quaternary alloys, relevant for novel optoelectronic applications.
Antimonide-based family holds the potential for developing a new generation of mid-infrared applications. Here, we report on the growth of InSbxAs1-x alloys on n− and p−type GaSb(100) substrates ...varying the Sb mole fraction (x), using the liquid phase epitaxy (LPE) technique. We show that the ternary alloy grown on the n−type GaSb substrate presents higher crystalline quality, thermal diffusivity and interfacial thermal conductivity, as compared to the one grown on pin equation type GaSb substrates which decrease as the Sb mole fraction (x) in the layer increases. Our results demonstrate that the InSbxAs1-x/n−GaSb heterostructure reaches the thermal equilibrium faster than the InSbxAs1-x/p−GaSb structure, with lower roughness, strain, as well as a better chemical abruptness at substrate-layer interface. We also find that the growth mechanism of the InSbxAs1-x alloy is constituted by In−As and In−Sb bonds. Furthermore, the Raman scattering spectra measured at different layer depths evidence that the crystalline quality improves with depth and allow the identification of an intrinsic depletion region. Since the InSbxAs1-x alloy presents a long-range atomic order grown on both n− and p−type GaSb substrates, the phonon-plasmon coupled L− and L+ modes are observed, and from the L+ coupled mode, we obtain the intrinsic carrier concentration and its variation with the Sb mole fraction. Therefore, this work provides important guidance on the structural, thermal, and chemical properties of the surface, bulk and interface of InSbxAs1-x alloys, that should be considered to improve the performance of future devices, such as better heat dissipation.$
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•InSbxAs1−x alloys on n− and p−GaSb substrates were grown by LPE.•Effect of the Sb content on InSbxAs1−x properties was found.•Analysis of surface, bulk and interface of InSbxAs1−x alloys.•Study of thermal diffusivity, interfacial conductivity and growth mechanism.•Study of crystalline quality and intrinsic carrier concentration.
Background
Few reported studies compare drug survival in moderate‐to‐severe psoriasis vulgaris.
Objectives
To describe and compare drug survival of systemic drugs, including biologic agents ...(infliximab, etanercept, adalimumab and ustekinumab) and classical drugs (acitretin, ciclosporin and methotrexate) in moderate‐to‐severe psoriasis.
Methods
This was a multicenter, prospective, cohort study of patients receiving systemic therapies between 2008 and 2013 in 12 hospitals in Spain. Baseline data and drug discontinuation were collected. Drug survival is presented using Kaplan–Meier survival curves. We compared adjusted risk ratios of serious adverse events (AEs) with results of survival analysis for AEs.
Results
A total of 1956 patients were included for analysis (1240 exposed to biologics during follow‐up and 1076 to classic therapies). Median follow‐up time was 3.3 years (0.0–5.1 years). There were 2209 discontinuations out of 3640 therapy cycles started. The main reason for discontinuation was lack of efficacy (36.4%) and remission (27.2%). Biologics showed a higher drug survival than classics and the pattern of survival results for all outcomes (positive or negative) were very similar. Adjusted risk ratios of serious AEs did not agree with results of survival analysis.
Limitations
A limitation is that this is an observational study with potential selection bias.
Conclusion
Survival as a proxy measure of drug safety in psoriasis is inadequate.
The aim of this study was to assess the accuracy of a Principal Components Analysis (PCA)-based method for reflectance reconstruction and color estimation of layered dental resin-based composites ...with different thicknesses.
Bi-layered samples of different clinically relevant thicknesses were created using shades of VITAPAN Excell (VE), VITAPAN Dentine (VD) and VITA Physiodens (VP), combined with their corresponding enamel shades. Spectral reflectance of all samples was measured over a black background using a non-contact spectroradiometer with CIE 45∘∕0∘ geometry. Two different PCA-based models, built from two different configurations of known samples, were proposed to reconstruct the spectral data and color of unknown layered samples. Root Mean Square Error (RMSE), Goodness of Fit (GFC), as well as ΔE00 with corresponding 50:50% acceptability and perceptibly thresholds (AT and PT) were used as performance assessment.
The 5-samples training set approach provided an average RMSE < 0.015 and GFC > 0.999 when measured and predicted spectral reflectances were compared, while for the 9-samples training set, RMSE < 0.0098 and GFC > 0.9999 were obtained. The overall mean color differences obtained with the 5-samples training set approach were ΔE00 = 0.99 (AT% = 96.25% and PT% = 32.50%), while using the 9-samples training set resulted in lower overall mean color differences: ΔE00 = 0.50 (AT% = 99.22% and PT% = 83.87%).
Within the framework of this study, the two proposed PCA-based configurations allow the prediction of the spectral reflectance of layered dental resin-based composites of different shades and thicknesses, with a high degree of accuracy.
•Reflectance data of layered dental materials can be estimated by PCA-based algorithms.•Training set size affects the accuracy of reflectance and color estimations.•Shade variations do not affect the accuracy of the estimation.•The accuracy of the estimation depends on type of dental resin composite.•Predicted vs. measured color differences are generally within acceptable limits.
Most of the athalassic saline and hypersaline lakes are located in arid and semiarid regions where water availability drives the hydrological dynamics of the lake itself and the associated ...ecosystems. This is the case of the Salada de Chiprana Lake, in the Ebro River basin (Spain). It is the only athalassic permanent hypersaline lake in Western Europe, and where rare and endangered bacterial mats exist. This work presents a robust hydrogeological conceptual model for the lake system. The model evaluates the contribution of groundwater discharge to the whole water budget and explains the hydrological behaviour of the lake system. The lake behaves as a flow-through system rather than a closed basin. About 40% of total water outflow from the lake occurs as groundwater, whereas evaporation accounts for the remaining 60%. The surface water inflows are variable, but the groundwater contribution seems almost constant, amounting to 13% of the average total water inflow and contributing 1.9% of salt income. The high water salinity of the lake is controlled by evaporation, by saline water inflows from irrigation return flows, and the by groundwater outflows. The role of groundwater should be taken into account when drafting the water and land planning, once the conditions for the conservation of the algal mats are defined. A major contribution of this study is the water balance in the Salada de Chiprana Lake, which is consistent with a robust hydrogeological conceptual model defined upon scarce hydrogeological, hydrochemical and isotopic data in the local context as conditioned by the regional behaviour. The water balance is a key tool to help to correctly manage this unique athalassic saline lake, and the approach used here can be extrapolated to other similar ecosystems around the world.
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•Regional groundwater flow lines discharge into the Salada de Chiprana Lake.•Groundwater discharging into the lake is recharged at the Iberian Range slopes.•Groundwater represents 13% of the total inflows into the Salada de Chiprana Lake.•The lake behaves as a flow-through system rather than a closed endorheic basin.•Lake water salinity controlled by evaporation, return flows and groundwater discharge.
Graphene oxide quantum dots were synthesized from carbonization, ultrasonic peeling, and oxidation of electrospun polyacrylonitrile (PAN) nanofibers. By energy scattering X-ray spectroscopy, a strong ...increase/decrease in the carbon/oxygen concentration was found during the stabilization stage and during carbonization, which resulted in the formation of carbon-enrich nanofibers. FTIR spectroscopy and Raman scattering results of electrospun PAN nanofibers demonstrated changes in structural and optical properties during the carbonization process. By X-ray diffraction was found that after the carbonization and oxidation processes of the PAN nanofibers, they showed a hexagonal graphene structure with two main crystallographic directions (002) and (101). The formation of graphene oxide quantum dots resulting from the ultrasonic exfoliation process was demonstrated by TEM with nanocrystal sizes of 10.98 nm, which were obtained after the ultrasonic exfoliation of carbonized/graphitized PAN nanofibers in highly oxidizing solvents. The absorbance in the UV spectral region showed a band at approximately 265 nm, which was assigned to the π→π* excitation of the π bonds of aromatic CC, and another band at 325 nm that was assigned to the n→π* transition of CO bonds, showing the presence of graphene oxide quantum dots (GOQDs). By Raman scattering is found that the synthesized GOQDs have a density of 22.6 ppm of crystalline defects, which indicates a higher order in their crystal lattices. The fluorescence and photoluminescence of the graphene oxide quantum dots showed radiative bands associated with possible crystalline defects in the graphene oxide quantum dot network, the radiative emissions of which correspond to the blue spectral region. The preparation protocol is simple and the yield of graphene oxide quantum dots is high.
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