Beer-Lambert Equation Research Articles

Experimental Study on Enhanced Methane Detection Using an MEMS-Pyroelectric Sensor Integrated with a Wavelet Algorithm.

An optical sensing approach that balances portability with cost efficiency has been designed for the reliable monitoring of fugitive methane (CH4) emissions. Employing a LiTaO3-based pyroelectric detector integrated with micro-electro-mechanical systems and a broad infrared source, the developed gas sensor adeptly measured CH4 concentrations with a low limit of detection of about 5.6 ppmv and showed rapid response times with t90 consistently under 3 s. Notably, the novelty of our method lies in its precise control and reduction of CH4 levels, enhanced by wavelet denoising. This technique, optimized through meticulous grid search, effectively mitigated noise interference noticeable at CH4 levels below 10 ppmv. Postdenoising, nonlinear regression analyses based on the modified Beer-Lambert equation returned R2 values of 0.985 and 0.982 for the training and validation sets, respectively. In conclusion, this gas sensor has been shown to be able to meet the requirements for early warning of CH4 leakage on the surface in various carbon capture, utilization, and storage projects such as enhanced oil or gas recovery projects using CO2 injection.

Study of the photocatalytic activity of clay supported TiO2 nanoparticles for methylene blue degradation.

The photocatalytic degradation of a methylene blue (MB) solution was studied using a formulation of TiO2 nanoparticles (NPs) suspended in a commercial antibacterial paint, and supported on clay strips. All experiments were carried out in a batch reactor containing a UV-C light source and the MB solution under stirring. Parameters such as catalyst mass loading, MB concentration, as well as catalyst properties were considered for the experimental procedure. The effect of the mass loading on the photocatalytic activity of the TiO2 formulations immobilized on the clay supports was evaluated using 100, 200, and 500 mg of TiO2 on 40 mL of paint, sampling the MB solution under degradation at 0, 2, 5, 10, 20, 50, 100 and 200 min. The aliquots were analyzed by optical spectroscopy in the 400-1000 range to determine the absorbance, calculate the concentration with the Beer-Lambert equation, and obtain the amount of MB degradation. The maximum photocatalytic degradation of MB for the supported photocatalyst was 52%, 55%, and 60%, respectively. For comparison, suspended TiO2 nanoparticles lead to ca. 95% of MB photodegradation in ca. 60 min. The supported photocatalysts were tested in three consecutive cycles of 200 min to study the mechanical and photocatalytic stability. The activity of the photocatalysts with mass loading of 100 and 200 mg TiO2 decreased to ca. 35% after the three cycles, while the formulation with 500 mg TiO2 remained stable for three cycles. The final samples of each cycle were characterized by XRF, discarding erosion of the material from the support.

Studying water infiltration on bentonite/sand blocks with MRI and X-Ray μCT techniques

Radioactive waste management agencies all around the world are focusing their efforts to provide a reliable technical solution to the Deep Geological Disposal (DGD) concept, in order to store high level (HLW) and intermediate level long lived (IL-LLW) radioactive waste. The protection and isolation of radionucleides is guaranteed by a set of barriers. Bentonite/sand blocks -in proportion of 40/60 on dry mass of the mixture- constitute the main core of the sealing barrier in the French concept run by the French National Radioactive Waste Management Agency (Andra). Its high swelling potential (>2MPa) during hydration, its low hydraulic permeability (<10-11 m/s) and its gas entry pressure (<2MPa) make it ideal to seal the DGD galleries excavated inside the host rock used as geological barrier. Bentonite/sand blocks are placed at unsaturated state during construction. Afterwards, water migration –in both liquid and vapour states- from the saturated host rock to the blocks will induce the humidification of the blocks until hydraulic equilibrium is reached, hypothetically reaching the saturation state. As this natural process will take hundreds of years, a multitude of experimental devices have been reported at laboratory [3, 5] and real scale [4] to understand the evolution of water transfer in bentonite mixtures and support the predictions of numerical models [1]. In laboratory experiments, samples made of a compacted bentonite mixture are usually placed inside a rigid cell connected to a water source. The infiltration of water is not measured directly but deduced by relative humidity gradients measured along the specimen height.
 Numerical models and experimental results have not yet reached accurate predictions of how long it takes for bentonite mixtures to hydrate until complete saturation or how the unsaturated hydraulic permeability evolves. In this context, there is a motivation to study this phenomena by advanced techniques able to capture, image and quantify water transfer through porous media. Thus, an experimental campaign based on Magnetic Resonance Imaging (MRI) and 3D X-Ray micro computed tomography (µCT) is proposed to analyze water infiltration in bentonite/sand blocks. MRI is extensively used in health sciences to create images where the contrast is given by the water’s hydrogen proton content in the different tissues of the body. For geological media, where water content is much smaller than in biological tissues and relaxation times of the porewater are shorter -from 0.1 to 2 ms for compacted bentonite/sand [2]- the experimental requirements are different and less documented. On the other hand, µCT scanning provides high spatial resolution images based on the contrast between the X-Ray absorption properties of the constitutive phases observed. Its temporal variations, in a bentonite/sand mixture, might be the result of concurrent phenomena, namely, porosity and saturation changes together with heterogenous motions induced by hydromechanical couplings -the swelling of bentonite solids when they absorb water-.
 On going MRI and µCT experimental campaigns on a PEEK cell aim at proving the suitability of these techniques to track the evolution of water infiltration in compacted bentonite/sand mixtures, characterizing the water front and the water content along the specimen in function of time. At this stage, preliminary MRI tests have shown the potential of Single Point Imaging (SPI) sequence to quantify, with one-dimensional images, the water content along the bentonite/sand specimen based on a linear correlation with its signal intensity. Preliminary X-Ray radiography tests (Figure 1) run on a cylindric cell of PMMA filled with small blocks of 12 mm in diameter and 10 mm high, prove that X-Ray radiography image analysis gives access to observable and quantifiable increase of absorption associated to the measured decrease in grey level at different transversal sections of the sample. This evolution is linked to the increase of apparent density of the solids -that indeed are absorbing the water-, as described by the Beer-Lambert equation. Even though apparent density increase is goverened by the augmentation of water content, changes in porosity due to the hydromechanical coupling along the sample cannot be neglected. Thus, observing the liquid phase evolution (hydraulics) by MRI, as well as the evolution of the solid/liquid phase (hydromechanics) by 3D-µCT imaging, will potentially provide complementary insight into the mechanisms governing water infiltration in bentonite/sand mixtures.

A fast magnetic vector characterization method for quasi two-dimensional systems and heterostructures

The use of magnetic vector tomography/laminography has opened a 3D experimental window to access the magnetization at the nanoscale. These methods exploit the dependence of the magnetic contrast in transmission to recover its 3D configuration. However, hundreds of different angular projections are required leading to large measurement times. Here we present a fast method to dramatically reduce the experiment time specific for quasi two-dimensional magnetic systems. The algorithm uses the Beer-Lambert equation in the framework of X-ray transmission microscopy to obtain the 3D magnetic configuration of the sample. It has been demonstrated in permalloy microstructures, reconstructing the magnetization vector field with a reduced number of angular projections obtaining quantitative results. The throughput of the methodology is × 10–× 100 times faster than conventional magnetic vector tomography, making this characterization method of general interest for the community.

Application of UV-Visible Spectroscopy in Kinetic Study of Molybdate Complexation Reactions and Phosphate Content Quantitation

UV-visible spectroscopic measurements were used to characterize the formation of two ammonium-molybdate complexes, to elucidate its kinetics, and to carry out spectrophotometric quantitation of percent phosphate content in selected commercially available fertilizers. The kinetic study of ammonium-molybdate [(NH3)6Mo7O24] reaction with hydrazine (N2H2) yielding ammonium-hydrazine-molybdate complex (AHM) and that of reaction of AHM with phosphate [PO4]3- to give phospho-ammonium-hydrazine-molybdate (AHPM) complex revealed that both proceed via zero-order kinetics (R2= 0.99) with rate constants in the order of 10-5 and 10-4 M/s respectively. The kinetic experiments revealed that the rate of formation of the AHM complex is sensitive to an increase in N2H2 ligand concentration. For both reactions, the highest complexation rates were observed within the first 1000 s. Complex dissociation and association equilibria events were observed at extended reaction periods in the kinetic experiments. The AHPM system (containing complexed phosphates) used in spectrophotometric quantitation of phosphate levels in fertilizer samples was found to obey the Beer-Lambert equation in the visible region at λ max. = 820 nm within the concentration range of 5 – 90% phosphate content (R2 = 0.99). Of the fertilizer randomized sampled from Nakuru Municipality in Kenya, and analyzed the percent phosphate content among the inorganic fertilizers was found to range between 61.7% - 82% with a mean of 72.86% +/- 6.98 SD. Whereas in the organic fertilizer samples investigated, it was found to range between 43.8% - 58.2% with means of 52.55% +/- 6.77 SD. The organic fertilizers were found to have significantly lower phosphate levels based on an unpaired t-test revealing that the mean percent concentrations between the two groups of fertilizer samples tested are significantly different at 95% CI (P value < 0.05).

Evaluation of a helicoidal flux photoreactor applied in the dicloxacillin degradation by UV-C/H2O2 and UV-A/photo-Fenton including the effect of photon absorption

The efficiency of a helical flow photoreactor in the oxidation of the antibiotic Dicloxacillin as a function of the recirculation flow, the local volumetric rate of photon absorption (LVRPA) and photonic efficiency using oxidation processes based on UV-C/H2O2 and UV-A/photo-Fenton were evaluated in this work. Mathematical modeling of the degradation process and experiments in lab-scale helicoidal reactor were done. Mathematical evaluation was supported in function of photon flux, mass balance and reaction rate law. The LVRPA was calculated by modified Beer-Lambert Equation. The effect of the concentration of hydrogen peroxide and iron (II) on the efficiency of the oxidation of the antibiotic Dicloxacillin was evaluated by means of the photo-Fenton. In 45 min, 100% degradation of dicloxacillin was achieved using 1.5 mM H2O2 and 7.32 μM ferrous ion in the photo-Fenton experiments with the helical flow photoreactor. The optical thickness of the reaction and distribution of energy absorption confirmed the kinetic and photonic efficiency performance. The prediction of the model presented a global error less to 2.4% between experimental and simulated data.

Remote Sensing of the Water Quality Parameters for a Shallow Dam Reservoir

This study examines the chlorophyll a content and turbidity in the shallow dam reservoir of Lake Dobczyce. The analysis of satellite images for thirteen wavelength ranges enabled the selection of wavelengths applicable for a remote determination of chlorophyll a and turbidity. The selection was completed as the test of the significance of the coefficients in the equation, which calculates the values of the parameters on the basis of reflectance. The reflectance of the reservoir surface differs from the reflectance of individual water components, and the overlapping of spectral curves makes it difficult to isolate the significant reflectance. In the case of Lake Dobczyce, the significant reflectance was for wavelengths 665, 705, 740, and 842 nm (chlorophyll a) and for wavelengths 705, 740, and 783 nm (turbidity). In the model, the natural logarithm of chlorophyll a or turbidity was a linear combination of the natural log reflectance and the squares of those logarithms. A lake surface reflectance also includes the bottom reflectance. The reflectance obtained from the Sentinel-2 satellite was corrected with a bottom reflectance determined using the Lambert–Beer equation. The reflectance of a given surface may vary with the position of both the satellite and the sun, atmospheric pollution, and other factors. Correction of reflectance from satellite measurements was performed, as reflectance changes for the reference surface; the reference reflectance was assumed as the first reflectance of the reference surface observed during the study. The models helped to develop the maps of turbidity and chlorophyll a content in the lake.

High transparent wood composite for effective X-ray shielding applications

The flexible and transparent film for X-ray radiation shielding have been fabricated successfully in the form of composites PVA/Gelatin/BaCO3/transparent wood. The wood samples were delignified for 3, 6, and 9 h to remove the lignin content. Beer-Lambert equation was used to calculate the shielding parameter based on the thickness of the sample and the intensity before and after applied all energy irradiation considered. FTIR and X-ray shielding test confirmed that the shielding able to absorb most of photon energy and well-interacting with atoms in samples. Low HVL shows the material was effectively block the radiation. The samples with 0.5 g BaCO3 showed the lowest HVL (0.72747 cm) compared to others composition. The linear attenuation coefficient was 1.37463 cm−1 at 55 keV with of 0.5 g of BaCO3. The mass attenuation coefficient also confirmed that the attenuation of composites increases (ex. 55 keV irradiation energy for 0.1 g BaCO3 is 0.793, 0.941 cm−1 for 0.3 g BaCO3, and 1.115 cm−1 for 0.5 g BaCO3) linearly along with increasing of BaCO3 concentration and shows good agreement with theoretical calculation from XCOM database. It is indicated that the PVA/Gelatin/BaCO3/transparent wood composites show high potentials as a new transparent and flexible shielding material for X-ray radiation application in medical sector.

TNFα Reduces the Maximum Respiratory Capacity of Mitochondria in Human Airway Smooth Muscle Cells

Previously, we reported that airway inflammation mediated by pro‐inflammatory cytokines such as TNFα induces hypercontractility and increased ATP consumption in human airway smooth muscle (hASM). We also found that TNFα induces an increase in maximum O2 consumption rate as well as mitochondrial biogenesis and an increase in mitochondrial volume density. However, when normalized to mitochondrial volume, maximum O2 consumption rate per mitochondrion is reduced in hASM after TNFα exposure. Unfortunately, standard respirometry (e.g., Seahorse) measures only the averaged maximum O2 consumption rate of a large number of cells. In the present study, we used a quantitative histochemical technique to determine the maximum velocity of the succinate dehydrogenase reaction (SDHmax) together with mitochondrial volume density in individual hASM cells. SDH is a key enzyme in the tricarboxylic acid (TCA) cycle as well as complex II in the electron transport chain (ETC), and SDHmax reflects the maximum respiratory capacity of individual mitochondrion. We hypothesized that TNFα decreases SDHmax per mitochondrion in hASM cells. hASM cells were dissociated from bronchial biopsies obtained during thoracic surgeries in patients with no history of asthma or chronic obstructive pulmonary disease. The hASM cells were treated with TNFα (20 ng/ml) or vehicle (DMSO) for 24 h, and SDHmax was measured using a solution containing 80 mM succinate (maximum substrate concentration) and 1.5 mM nitro blue tetrazolium (NBT) as the reaction indicator. As the SDH reaction proceeded, the hASM cells were imaged in 3D (Z optical slice of 0.5 μm) using an oil‐immersion ×60/1.4 NA objective on a Nikon Eclipse A1 laser scanning confocal system. The change in optical density (OD), reflecting the accumulation of NBT diformazan reaction product in the hASM cell, was measured every 15 s over a 10 min period. Based on the Beer‐Lambert equation, the slope of the change in OD was used to determine SDHmax expressed as mM fumarate/L tissue/min. To determine mitochondrial volume density, the same hASM cells were also loaded with MitoTracker Green (500 nM) and imaged in 3D. We found that mitochondria were more fragmented after TNFα exposure although mitochondrial volume density increased. When SDHmax was normalized to mitochondrial volume, we found that SDHmax per mitochondrion decreased in hASM cells, consistent with the reduction in maximum O2 consumption per mitochondrion that we previously observed. Thus, the increased energetic demand induced by inflammation (TNFα) are met by mitochondrial fragmentation leading to biogenesis and an increase in mitochondrial volume density rather than an increase in mitochondrial respiratory capacity.

How does structure matter? Comparison of canopy photosynthesis using one- and three-dimensional light models: a case study using greenhouse cucumber canopies

Abstract One-dimensional light models using the Beer–Lambert equation (BL) with the light extinction coefficient k are simple and robust tools for estimating light interception of homogeneous canopies. Functional–structural plant models (FSPMs) are powerful to capture light–plant interactions in heterogeneous canopies, but they are also more complex due to explicit descriptions of three-dimensional plant architecture and light models. For choosing an appropriate modelling approach, the trade-offs between simplicity and accuracy need to be considered when canopies with spatial heterogeneity are concerned. We compared two light modelling approaches, one following BL and another using ray tracing (RT), based on a framework of a dynamic FSPM of greenhouse cucumber. Resolutions of hourly step (HS) and daily step (DS) were applied to simulate light interception, leaf-level photosynthetic acclimation and plant-level dry matter production over growth periods of 2–5 weeks. Results showed that BL-HS was comparable to RT-HS in predicting shoot dry matter and photosynthetic parameters. The k used in the BL approach was simulated using an empirical relationship between k and leaf area index established with the assistance of RT, which showed variation up to 0.2 in k depending on canopy geometry under the same plant density. When a constant k value was used instead, a difference of 0.2 in k resulted in up to 27 % loss in accuracy for shoot dry matter. These results suggested that, with the assistance of RT in k estimation, the simple approach BL-HS provided efficient estimation for long-term processes.

Comparison of Gamma Sources (Cobalt and Cesium) for Density Measurement of Metals and Alloys via Using Transmission Technique

One of the solutions for density measurement is to make use of gamma-ray transmission technique. We studied by this technique, using by Co-60 and Cs-137. Each source, without materials in geometry, was counted and noted intensities as (I0). All materials were counted and noted intensities as (I). [I/I0] rates were calculated. Now, density of materials could be determined via using Beer-Lambert Equation. Experimental application was performed on industrial metals or metal alloys like lead&copper and steel&brass. Given densities and obtained densities were compared. Differences or deviations for lead, stell copper and brass are -5.07; 0.26; 1.11; -5.73 (Co-60) and 1.07; 3.08; -0.22; 2.34 (Cs-137) consequently. It could be said that, these differences are still in acceptable limits.

The modelling of Surface-Water photoreactions made easier: introducing the concept of ‘equivalent monochromatic wavelengths’

The recent development of successful model approaches that predict the photochemical behaviour of surface waters has greatly aided in the understanding of how water environments work and will likely work in the future, from a photochemical point of view. However, the inherent multi-wavelength (polychromatic) nature of environmental photochemistry causes the relevant mathematics to be quite complex, which discourages many scientists to carry out photochemical calculations. To greatly simplify model mathematics, this paper proposes a new approach that is based on a monochromatic approximation to the polychromatic problem, introducing the concept of what is here defined as equivalent monochromatic wavelengths (EMWs). The EMW is the single wavelength that reproduces the behaviour of the polychromatic system, using a monochromatic (Lambert-Beer based) equation. The EMW approach largely simplifies calculations, getting rid of integrals and allowing for much more straightforward and manageable equations to be obtained. In particular, this work shows that: (i) the EMW approach, although approximated, entails a negligible loss in accuracy compared to the exact polychromatic treatment of photochemical reactions; (ii) in the case of direct photolysis, the quantum yield is to be replaced by an apparent photon efficiency that is not bound to be < 1 (quantum yields can actually be > 1 for chain reactions and few other cases, but this is not the point here); (iii) the monochromatic Lambert-Beer equations work in most cases once the EMW is identified, with the present exception of sunlight absorption by chromophoric dissolved organic matter (CDOM). The latter spans a very wide wavelength range (from 300 to at least 600 nm), which makes a single-wavelength treatment more difficult. However, a relatively small modification to the monochromatic Lambert-Beer equation allows for successfully using the EMW approach, in the case of CDOM as well. The near-perfect coincidence between polychromatic and EMW-based predictions of photodegradation kinetics is here shown for the pollutants atrazine, bentazone, carbamazepine, diclofenac, diuron and ibuprofen. Extension to additional compounds requires translation of the traditional, polychromatic language into the EMW one. Hopefully, this contribution will introduce a new paradigm in the mathematical description of photochemical reactions in environmental waters. It could also become a new and simple way to treat multi-wavelength systems in general photochemistry studies, thereby completely changing the way multi-wavelength problems are dealt with.

A Monochromophoric Approach to Succinct Ratiometric Fluorescent Probes without Probe-Product Crosstalk

Ratiometric probes facilitate quantitative studies via self-calibration and are cherished for bioimaging. Often, a small probe-product spectral separation leads to crosstalk, but the rational devel...

Influence of Different Satellite Imagery on the Analysis of Riparian Leaf Density in a Mountain Stream

In recent decades, technological advancements in sensors have generated increasing interest in remote sensing data for the study of vegetation features. Image pixel resolution can affect data analysis and results. This study evaluated the potential of three satellite images of differing resolution (Landsat 8, 30 m; Sentinel-2, 10 m; and Pleiades 1A, 2 m) in assessing the Leaf Area Index (LAI) of riparian vegetation in two Mediterranean streams, and in both a winter wheat field and a deciduous forest used to compare the accuracy of the results. In this study, three different retrieval methods—the Caraux-Garson, the Lambert-Beer, and the Campbell and Norman equations—are used to estimate LAI from the Normalized Difference Vegetation Index (NDVI). To validate sensor data, LAI values were measured in the field using the LAI 2200 Plant Canopy Analyzer. The statistical indices showed a better performance for Pleiades 1A and Landsat 8 images, the former particularly in sites characterized by high canopy closure, such as deciduous forests, or in areas with stable riparian vegetation, the latter where stable reaches of riparian vegetation cover are almost absent or very homogenous, as in winter wheat fields. Sentinel-2 images provided more accurate results in terms of the range of LAI values. Considering the different types of satellite imagery, the Lambert-Beer equation generally performed best in estimating LAI from the NDVI, especially in areas that are geomorphologically stable or have a denser vegetation cover, such as deciduous forests.

Detection of an emerging contaminant in water by dielectric properties in microwave range

The complex relative permittivity study of samples of liberdux® syrup dissolved in distilled–deionized water is presented. It should be mentioned that excess of this syrup as pharmaceutical residual in water is considered an emerging contaminant. The study covers liberdux® concentrations from 0% v/v to 100% v/v, which were measured from 500 MHz to 20 GHz. For each sample, the parameters of the Havriliak–Negami model are presented in the range of measurement. Also, the uncertainty study was carried out to determine the sensitivity of the open coaxial probe and it was established that, for concentrations between 8% v/v and 100% v/v, it is possible to determine the concentration of liberdux® in water by the dielectric constant and the loss factor. In addition, a linear relationship was found between the concentration of liberdux® and the α parameter of the Havriliak–Negami model. The study of liberdux® concentrations was also performed with a spectrophotometer and the Beer–Lambert equation. It was established that the spectrophotometer and the open coaxial probe can be used as complements to measure concentrations, the spectrophotometer being the instrument for measuring low concentrations by absorbance, and the open coaxial probe for high concentrations by microwave permittivity.

Canopy cover evolution, diurnal patterns and leaf area index relationships in a Mchare and Cavendish banana cultivar under different soil moisture regimes

The biggest abiotic threat to banana (Musa spp.) production is water deficit, but physiological indicators in plantations are lacking. Canopy Cover (CC) seems to be a relevant parameter, but so far not used in banana fields. Field experiments were conducted to determine the effect of optimal irrigation (FI) versus rainfed (RF) on CC and Leaf Area Indices (LAI) in two experiments with different cultivars (Mchare ‘Huti Green’ [HG, AA] and Cavendish ‘Grand Naine’[GN, AAA]) (n = 3 for HG, n = 4 for GN) until harvest of cycle 1 (C1), studying C1 and C2 plants. Soil moisture was followed using Time Domain reflectometry. CC and LAI were reduced 8–9 weeks after the start of soil moisture divergence between RF and FI treatments in both experiments (p < 0.05), leading to a reduction in CC growth rate (r) and maximum CC (CCmax) in RF plots (p < 0.05). On a daily timescale, CC varied diurnally (i.e. was reduced) under high evaporative demands, whereby soil moisture depletion increased the CC reduction. Cultivar specific CC-LAI curves were created following the Lambert-Beer equation, whereby HG had a lower extinction coefficient than GN (0.52 vs. 0.67). CC growth over time seems a promising indicator for water deficit in the field. Diurnally, CC is more affected by evaporative demand than soil moisture depletion, although soil moisture depletion increases CC diurnal drops under high ET0.

Fluorescence properties of Phycocyanin and Phycocyanin-human serum albumin complex

In this work, the fluorescence properties of Phycocyanin (PC) and the corresponding quenching effects are investigated in attendance of human serum albumin (HSA). At first, PC is excited at 532nm using CW SHG Nd:YAG laser, then the emission wavelength, Stokes shift, quantum yield, extinction constant and self-quenching coefficient are obtained based on the modified Beer-Lambert equation. It is shown that a notable red shift appears in terms of PC concentration. According to the fluorescence spectra, the addition of HSA in PC solution leads to a significant reduction in the fluorescence signal via quenching events, however a lucid blue shift takes place in the same time. Stern-Volmer formalism is used to determine the quenching constant (KS), the number of binding sites (n) between PC and HSA as well as the association constant Ka for the purpose of facile transportation to the target in the context of drug delivery. Eventually, temperature dependent coefficients and corresponding spectral shifts are investigated over a wide range of temperatures at a couple of distinct PC concentrations to attest the dominant static quenching takes place. The rate of conjugate formations elevates at low temperatures leading to a certain blue shift. Furthermore, large KS is measured in the course of signal reduction, particularly at low PC populations. In fact, PC conjugation to HSA is essential interaction to enhance chemo drug transportation. Here, at the body temperature, the quenching coefficient decreases to facilitate the drug release. Moreover, the spectral shift of fluorescence emission can be useful for simultaneous monitoring and drug delivery treatment.

Corrigendum for âInvestigation on âspontaneous fermentationâ and the productivity of microbial exopolysaccharides by Lactobacillus plantarum and Pediococcus pentosaceus isolated from wheat bran sourdoughâ LWT â Food Science and Technology 96 (2018) 686â693 (LWT (2018) 96 (686â693), (S0023643818304997), (10.1016/j.lwt.2018.05.071))

A reader reported complained about errors in the original paper, which was sent to the authors. The authors responded to the complaint but did not submit a corrigendum. To provide a balanced view, the written documents of both, the reader (reporter) and the author, are presented here; Reporterâ�� comments. In this study, the differences between the features of exopolysaccharides produced by two different bacteria L. Plantarum and P. Pentosaceus were investigated. According to the results in Table 2, these polysaccharides have different molecular weights, and percentages of protein and polysaccharides. However, it is not clear why FTIR spectra of these two polysaccharides have only slight differences in the identified peak wave numbers (indicated in the image per case). In other words, the â��peak sizeâ��, â��the ratio of peak sizeâ�� and â��peaksâ�� locationsâ��, in both of the exopolysaccharide produced by L. Plantarum and P. Pentosaceus are quite similar. While, according to Table 2, it is expected that the transmittance of the samples be quite different in the specific range of proteins and polysaccharides. Hence, it seems that one of the spectrums was prepared by editing the other spectrum using a graphical software. Author's response: For FT-IR characterization of EPS, both samples were sent to a specified laboratory in Ferdowsi University of Mashhad where the analysis was performed using FT-IR spectrophotometer (Thermo Scientific Nicolet 6700, Avatar 370 FT-IR, USA). The data, Exel files and the spectrums generated by that laboratory are attached as a supplement to this report to show the invalidity of the claim against us regarding the edition of spectrums by a graphical software! By observing the data (which are inserted to the following table for review) and the overlay graph on the attached Excel file (Supplement 1), slight differences can be observed. However, the functional groups present in isolated EPS including hydroxyl, carboxylic acid and ester groups with DPPH radical scavenging activity are found similar in both EPS samples. None of the referees from LWT put any comment against these results and trends. Table presented Reporter's analysis of author's response: It is very unlikely that wavelengths and peak intensities in FTIR transient diagrams of two EPSs with different concentrations of protein and polysaccharide, which were obtained from two different bacterial genera, to be exactly the same. In the following, we will elaborate to support our claims with scientific references. A) Transmittance has an exponential relation with the concentration. According to Beer-Lambert Law, the relation between transmittance and the sample concentration is obtained from this equation: Table presented T = transmittance (relative amount of light passing through a sample) I, I0 = intensity (Wm-2) of transmitted and incident radiation, respectively Iµ = molar absorptivity (m2molâ��1 or Mâ��1cmâ��1) or how strongly a chemical species absorbs light at a given wavelength b = path length (distance light travels through the chemical species) c = molar concentration of chemical species A = absorbance (relative amount of light absorbed by sample)Each change in the concentration of materials and consequently the concentration of functional groups and bonds will lead to an exponential change in the FTIR spectrum. Therefore, considering the concentration of compounds mentioned in the paper and the Beer-Lambert equation, the ratio of the transmittance difference shown in the FTIR diagram for protein and polysaccharide-related functional groups between EPS obtained from Lactobacillus and Pediococcus should be exponentially higher than the ratio of the differences between their concentrations. Considering these issues, the difference between the transmittance of the samples, according to the table presented in the authors' responses, is negligible compared to the differences between the protein and polysaccharide concentrations as presented in Table 2. Figure presented B) According to Shang, Xu, and Li and Smith, the range of EPS fingerprint is between 900 and 1200 cmâ��1. However, the authors introduced this range between 500 and 1300 cmâ��1 without citing any references. Also, none of the peaks in the table provided by the authors in their answers are in this range.C) According to Sigma-Aldrich IR spectrum database, Smith, Helm and Shao, the characteristic peak of the proteins in EPS is observed at 1580â��1650 cmâ��1. In the table provided by the authors in their answers, the difference between the transmittance of EPSs obtained from Lactobacillus and Pediococcus is negligible, in contrast to their protein concentration that is significantly different.D) The difference in material composition leads to shifting the peaks of functional groups to higher or lower wavelength and shifting a peak of less than 10 cmâ��1 is usually meaningless. Therefore, according to the FTIR diagram, peaks were not shifted that does not make sense. © 2020 Elsevier Ltd

Mathematical particle model for microwave drying of leaves

In this work, the model of particles for microwave drying by means of assisted force convection for blueberry leaves is described. A one-dimensional particle model is made in the direction of the thickness of the leaf. Only the phases of water during drying are considered. The mass and energy equation in the particle model develops. The effective diffusivity and the Arrhenius equation for the water phase (liquid and vapor) are considered in the mass equation. The energy equation considers the Lambert-Beer equation. The simulation is performed for different cases of microwave powers (100, 300, 400 W) and temperatures (50, 60 and 70 °C) The activation energy and the pre-exponential factor in the Arrhenius equation are taken from the kinetic analysis prior to this Work The temperature and mass profiles for some experimental and theoretical cases are compared, and it is observed that the model considered gives good results of adjustment between the experimental and the theoretical.

Estimating leaf area index and light extinction coefficient using Random Forest regression algorithm in a tropical moist deciduous forest, India

Leaf area index (LAI) and light extinction coefficient (k) are the key structural parameters controlling many canopy functions like radiation and water interception, radiation extinction, water and gas exchange. The present study aims at developing predictive models for generating spatial distribution of LAI and k by integrating remote sensing imagery and field data. The study was carried out in a tropical moist deciduous forest of Uttarakhand, India. Various spectral variables were derived from Landsat 8 Operational Land Imager (OLI) data of 8 May 2017 to predict LAI and k. In-situ measurements of LAI, incident Photosynthetically Active Radiation (PAR) above canopy (Io) and below canopy (I) were taken using CI-110 Plant Canopy Imager. Canopy gap fraction and k (using Beer-Lambert's equation) were calculated. Random Forest (RF) algorithm was used to predict the spatial distribution of LAI and k using the best predictor variables. The best predictor variables for LAI included band 6 (Short wave infra-red (SWIR) -1) and band 7 (SWIR-2), tasseled cap wetness, Moisture Stress Index (MSI), and Normalized Difference Moisture Index (NDMI). For prediction of k, the best predictor variables were band 6 (SWIR-1) and band 7 (SWIR-2), NDMI, tasseled cap wetness, MSI and Normalized Difference Vegetation Index (NDVI). These variables were selected to generate RF-based models to predict LAI and k. On validation, the models were able to predict LAI with R2 = 0.79 and % RMSE = 14.25% and k with R2 = 0.77 and % RMSE = 11.98%. The predicted LAI and k followed an inverse relation in accordance with the Beer Lambert's Law. The results showed that RF can be effectively applied to predict the spatial distribution of LAI and k.