The leaves of Agave tequilana Weber variety Blue represent a viable, inexpensive, and renewable source of lignocellulosic biomass and fructans for the production of second generation biofuels. The objective was to study the effect of drying temperature on the release of reducing sugars for the agave leaves. It was found that with pretreatment‐drying at 100°C for 30.5 ± 1.0 min had a maximum of the release of reducing sugars with a 66% increment compared to 60°C. An aqueous extract obtained from the powder of the leaves after drying did not show the presence of furfural and hydroxymethylfurfural compounds. Phenolic compounds were detected in order of 120.8 ± 1.0 mg L−1 below 1 g L−1 reported to cause inhibition of the alcoholic fermentation. In addition the drying of the leaves also can be used as preservation of agave leaf for biomass storing. The results show that pretreatment‐drying allow increase the release of reducing sugars, avoids thermal degradation and does not produce significant concentrations of fermentation inhibitors. Practical Applications The research in industrial waste materials has received special attention worldwide because it is potential for production of biofuels. This study propose a simple method of drying that acts as a thermal pretreatment of Agave tequilana Weber variety Blue leaves that increases the release of reducing sugars, avoids thermal degradation, not produce significant concentrations of fermentation inhibitors for ethanol production and can be used as a preservation method for storing biomass of the agave leaves. The results would be useful not only in the energy field but also in the alimentary and pharmaceutical industry. Fructans and phenolic compounds found in the agave are used as functional ingredients in the food industry and also bioactive compounds that by themselves promotes future research for the Agave tequilana.

SIGNIFICANCE Electronic display devices used before bed may negatively affect sleep quality through the effects of short-wavelength (blue) light on melatonin production and the circadian cycle. We quantified the efficacy of night-mode functions and blue-light–reducing lenses in ameliorating this problem. PURPOSE The purpose of this study was to compare the radiation produced by smartphones that reaches the eye when using night-mode functions or blue-light–reducing spectacle lenses. METHODS Radiant flux of 64 smartphones was measured with an integrating sphere. The retinal illuminance was calculated from the radiant flux of the smartphones. For the night-mode functions, the spectra produced by the smartphones were measured. The transmittance of four blue-light–reducing spectacle lenses, which filter light with either antireflective coatings or tints, was measured using a spectrometer. To determine the impact of blue-light–reducing spectacles, the radiant flux of the smartphone was weighted by the transmission spectrum of these glasses. Visual and nonvisual (circadian) parameters were calculated to compute the melatonin suppression values (MSVs) through a logistic fitting of previously published data. The MSV was used as the figure of merit to evaluate the performance of blue-light spectacles and smartphone night-mode functions. RESULTS Night-mode functions in smartphones reduced MSVs by up to 93%. The warmest mode produced the least suppression. Blue-light–reducing spectacles reduced melatonin suppression by 33%, the coated lenses being more efficient than tinted lenses. CONCLUSIONS All smartphones in this study emit radiant power in the short-wavelength region of the visible spectrum. Such smartphones may impair the regulation of circadian cycles at nighttime. The activation of night-mode functions was more efficient than the commercially available blue-light–reducing spectacle lenses in reducing the amount of short-wavelength light (up to 2.25 times). These results can be extrapolated to most electronic devices because they share the same type of white radiant sources with smartphones.

Pseudomorphic In0.2Ga0.8As∕GaAs quantum wells (QWs) were grown by molecular beam epitaxy on GaAs substrates oriented along (11n) directions, with n=1,2,3,4. The optical and structural properties of the heterostructures were studied by photoluminescence (PL), photoreflectance (PR) spectroscopy, and atomic force microscopy measurements. The energy transitions in the QWs have two contributions, a blueshift due to the compressive strain, and a redshift due to the quantum confined Stark effect produced by the piezoelectric field present in the QWs. A variational approach was employed to calculate the QWs ground energy transitions employing an ideal potential well with sharp interfaces. The theoretical energy transitions were fitted to the PL peaks energy to obtain the electric fields in the InGaAs QWs. The obtained electric fields show discrepancies with theoretical piezoelectric fields calculated from the strain present in the QWs. In order to overcome these discrepancies, we propose to include interdiffusion effects of In at the well interfaces. The matrix transfer method was implemented to numerically solve the Schrödinger equation taking into account In interdiffusion effects by including an asymmetric potential well with a profile depending on the details of the In incorporation. With interdiffusion effects included in the energy level calculations, and assuming the expected piezoelectric fields, the theoretical results reproduce very well the experimental values of PL and PR.

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In this work, the influence of the surface depletion layer on the formation of a two-dimensional electron gas in AlGaAs/GaAs modulated doped heterostructures is studied. The authors explore a method for estimating the depletion region inside of the GaAs-based heterostructures by using the longitudinal optical and L- amplitude modes observed in Raman spectra, which are supported by the modeling results. The authors found that the position of the topmost doping layer changes the electron distribution in the heterostructure and decreases the influence of the depletion layer. Similar effects are perceived when an optimized solution of (NH4)2SX and isopropanol is employed. The authors present a method to evaluate the formation of a double two-dimensional electron gas in a heterostructure by the adequate use of modulation line in the photoreflectance spectroscopy.