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A selective, facile, and highly efficient spectrophotometric approach was established for the determination of 1,4-dioxane in drinking water quantitatively. This approach depends on the reaction selectively of 1,4-dioxane with 1-Amino-2-naphthol-4-sulphonic acid (AHSA) to give an instantly complex measured at 340 nm. The maximum spectra development with high intensity of dioxane-AHSA complex was obtained at 15 min. Variable parameters that affecting the dioxane-AHSA efficacy were estimated and optimised. Under optimal conditions, the dioxane-AHSA complex obeyed Beer's law within the range of 0.5–15 mg/L of 1,4-dioxane with a regression factor of 0.996 (n = 5) and a detection limit of 16 µg/L. The results of precision and accuracy within-day were ≤2.0% in terms of relative standard deviation (RSD%), which confirmed the reproducibility of the analytical performance. The proposed method was applied successfully in the simultaneous assessment of 1,4-dioxane in an aqueous solution. The accuracy and reliability of the developed approach recommended being applied in all quality control of water companies without the use of sophisticated instrumentation and procedure. [ABSTRACT FROM AUTHOR]

This study explores the dynamics of liquid holdup in a lab-scale co-current two-phase upflow moving packed bed reactor, specifically examining how superficial gas velocity influences the line average external liquid holdup at a fixed superficial liquid velocity. Utilizing gamma-ray densitometry (GRD) for precise measurements, this research extends to determining line average internal porosity within catalyst particles. Conducted with an air–water system within a bed packed with 3 mm porous particles, the study presents a novel methodology using Beer–Lambert's law to calculate liquid, gas, and solid holdups and catalyst porosity that is equivalent to the internal liquid holdup that fills the catalyst pores. Findings reveal a decrease in liquid holdup corresponding with increased superficial gas velocity across axial and radial locations, with a notable transition from bubbly to pulse flow regime at a critical velocity of 3.8 cm/sec. Additionally, the lower sections of the packed bed exhibited higher external liquid holdup compared to the middle sections at varied gas velocities. The liquid holdup distribution appeared uniform at lower flow rates, whereas higher flow rates favored the middle sections. [ABSTRACT FROM AUTHOR]

This study unveils an advanced methodology for characterizing various types of cow's milk based on their optical properties, aiming to establish a straightforward yet comprehensive method. This study uses fundamental principles such as Snell's Law and Fresnel coefficients to determine and demonstrate critical angles for total internal reflection and reflectance at p polarization. Notably, milk composition, particularly fat content, significantly and remarkably influences its refractive index, with higher fat content leading to elevated values. Additionally, the extinction coefficient, derived through the Beer–Lambert law, provides valuable and essential information regarding light absorption and scattering within the milk samples. The significance of this research relies upon its ability to comprehensively analyze various optical properties of milk, including critical angles, reflectance, and extinction coefficients. By doing so, it offers an exhaustive and detailed understanding of how milk responds to light across different wavelengths and angles of incidence. Moreover, the technique effectively distinguishes milk types based on their fat content and particle characteristics. This novel characterization technique holds promise for various applications within the dairy industry, such as milk quality control, classification, and adulteration detection, which is crucial for maintaining consumer trust and safety. [ABSTRACT FROM AUTHOR]

Pulse oximetry uses noninvasive optical measurements of light transmission from each of two sources through vascularised living tissue over the cardiac cycle (SpO 2). From those measurements, the relative amount of oxygenated haemoglobin (SaO 2) in circulating blood can be deduced. Recent reports have shown that, compared with SaO 2 measurements from blood samples, SpO 2 measurements are biased erroneously high for patients with dark skin. We developed a new method, spectrally resolved photoplethysmography (srPPG), to examine how spectral bandwidth affects the transmission of polychromatic light through the fingertip across the cardiac cycle. We measured and recorded the spectral transmission through the fingertip as the O 2 concentration in inspired air was reduced. We applied digital spectral filters of two different bandwidths, narrow or broad, to the same srPPG recordings to determine whether SpO 2 readings systematically varied for the two bandwidths. The srPPG method also allowed us to measure the fractional amount of melanin in the optical path. The effect of melanin content on the ratio of SpO 2 readings for narrow and broad spectral bandwidths was analysed. We hypothesised, based upon the Beer–Lambert law, and then showed experimentally, that the light emission spectra of light-emitting diode light sources, as used in commercial pulse oximeters, result in erroneously high SpO 2 measurements for patients having greater melanin concentrations in their skin than those of the subject pool used for instrument calibration. To eliminate melanin bias, pulse oximeters should use much narrower spectral bandwidths than those used in current models. [ABSTRACT FROM AUTHOR]

Herein, an accurate and simple spectrophotometric method for investigating cefixime in different formulations is reported. The proposed method elaborates on the complexation of cefixime with vanadyl sulfate in acidic media. The yellow color complexation product manifested its maximum absorbance peak at around 321 nm, and obeyed Beer's law in 2 × 10−6–1 × 10−4 M cefixime concentration. Obtained spectroscopic data were used to calculate standard deviation (S), limit of detection (LOD), limit of quantification (LOQ), and relative standard deviation (RSD) as 6.5 × 10−5, 1.96 × 10−4, 6.5 × 10−4 M, and 0.057%, respectively. In addition, the formation constant associated with the complex obtained, calculated as 5.7 × 1016, indicates that the final complex was remarkably stable. [ABSTRACT FROM AUTHOR]

When the monochromatic light passes through a random attenuating medium, the radiant intensity drops exponentially with the length of the path and attenuation coefficient. The law of exponential decay was called the law of Bouguer, Lambert, Beer or some combination of these three. Here we refer to it as the modified Beer–Lambert law due to the arrangement proposed in the current work. This work aims to use UV–Vis spectroscopy and apply Beer–Lambert law; the feasibility of the work is assessed and shows the possibility of validating a beam intensity measurement experiment in two experimental situations with a known constant. The empirical part of the work consists of changes in chemical or physical properties. The first experimental situation consists of the variation of the concentration of the medium and evaluates the absorption of the laser beam. In this situation is used industrial synthetic dye. The second experiment also assessed the absorption of laser intensity, using variations of the number of films poly (ethylene terephthalate) polymeric sums found in the PET bottle. The values found for constant were ≈ 2.697 in the variation of concentration of synthetic dye in blue color, and for the condition of PET, films were found and ≈ 2.699. The value of the constant experimentally found approaches the Euler number. And they are so, proving that the Euler number can be determined experimentally in a system of Markovian non-interagent particles and how to experimentally validate a result by the association of a constant known in the literature. [ABSTRACT FROM AUTHOR]

Unclear light propagation in mixed fibers has resulted in unachievable masses of primary fibers, in particular thin two-mixed fiber assemblies for decades. Hereby, a modified mixed medium addition theorem of the Kubelka-Munk transmission model is proposed to address this issue. This theorem was constructed by introducing a transfer function in the common ones on scattering coefficients, and such a transfer function takes both the mass proportion of each component and the reflectivity of mixed material into consideration. This opens up a new avenue for understanding the possible light mechanism of color mixed fiber assemblies. The proposed method demonstrated excellent accuracy in determining the primary masses of 48 specimens, with an average mean absolute error of only 2.23 mg. In comparison, the Lambert-Beer law yielded a much higher average mean absolute error of 8.66 for all types of blended samples. Such superiority was particularly obvious in white-black mixed samples, probably due to its comprised reflectance. In brief, this proposed theorem shows a high-quality prediction accuracy level in fiber mass and can be expanded to detect and control mixed fibers, as well as fiber length and uniformity detection through further study. [ABSTRACT FROM AUTHOR]

A simple, economical and sensitive indirect spectrophotometric method for the determination of furosemide in its pure form and in pharmaceutical preparations is described. The method is based on the oxidation of furosemide by permanganate in acidic medium, then the reaction of the remaining potassium permanganate to oxidize the dye Eriochrome Black-T at a wavelength of 535 nm. The method follows Beer's law within the range (0.25-10) μg mL-1 and the molar absorbance is 1.5×104 L mol-1 cm-1. The value of the determination coefficient was 0.9984, the recovery rate was 100.53 % and the relative error value was 1.12 %, while the value of the limit of detection (LOD) and limit of quantification was (LOQ) 0.118 and 0.395 μg mL-1 respectively. It was found that the method does not suffer from interactions, and the method can be applied to pharmaceutical preparations (ampoules and tablets). [ABSTRACT FROM AUTHOR]

Based on oxidative coupling reactions utilizing the synthesized organic reagent 2-amino-5-(paraaminophenyl)-1,3,4-thiadiazole in acidic media, and with potassium dichromate as an oxidizing agent, a spectrophotometric method has been established for determining methyldopa and levodopa. For these drugs, the resultant complex exhibits peak absorption at 401.5 nm and 415 nm, respectively. The method adheres to Beer's law in the ranges of 1-55 µg ml-1 and 2.5-170 µg ml-1, with molar absorption coefficients of 0.24 x 104 and 0.116 x 104 L mol-1 cm-1, respectively. The quantification limit (LOQ) is set at 1.5769 µg ml-1 for methyldopa and 3.0616 µg ml-1 for levodopa, yielding recovery rates of 100.14% and 100.34%, and relative standard deviation rates of 2.748% and 0.779%. The nature of the resulting complex was examined using the continuous variation method (Job's method) and molar ratios, revealing a 1:2 ratio (reagent to drug compound) for both drugs. This method has been successfully applied to pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Simple, accurate and sensitive spectrophotometric, chemometric and chromatographic methods were used for the simultaneous determination of emtricitabine (ETC) and tenofovir disoproxil fumarate (TDF) in tablets. In 1st derivative spectrophotometry, the first derivative spectra of the solution of ETC and TDF in water were recorded as Δλ = 4 nm and the first derivative absorbances were measured at the zero-crossing points at 297.3 and 281.2 nm for ETC and TDF, respectively. In ratio of the 1st derivative spectrophotometry measurements were recorded at 239.0 and 270.2 nm for ETC and TDF, respectively. Then analytical signals were measured at the wavelengths corresponding to either maximum or minimum for both drugs. For these spectrophotometric methods Beer's law is obeyed in the concentration range of 2-15 μg mL-1 for both drugs. As chemometric method, the PLS technique was used. In chromatographic method, the separation was achieved on a C18 column with DAD (262 nm) and isocratic elution of methanol, acetonitrile and 0.1 % orthophosphoric acid in the volume ratio of 40:40:20, respectively, containing the mobile phase. The mean recovery and the relative standard deviation of the methods were found as 97.51-100.17 % and 0.55-1.26 % respectively. All these methods were statistically compared, and they were successfully applied to a pharmaceutical preparation. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel approach to estimate the sub-surface temperature (and thermal gradient) distribution during melting/solidification and its time evolution using in situ dynamic synchrotron X-ray radiography data is proposed in this work. The proposed approach uses the Beer–Lambert's law as a physical basis and is demonstrated using an in situ laser spot-melting experiment on Ti–6Al–4V alloy. This methodology also incorporates the recipe described previously by Gilbert and Deinert allowing for the extraction of a "radially-resolved" temperature distribution. [ABSTRACT FROM AUTHOR]

The highly reactive 5-Chlorosalicylaldehyde thiosemicarbazone (CSTSC) has been employed as an extractive reagent to create a simple and precise spectrophotometric technique for detecting Cu(II) spontaneously. The complex of 5-Chlorosalicylaldehyde thiosemicarbazone and Cu(II) has been quantitatively extracted in butyl acetate in the pH range of 5.4-6.4 after equilibrating for 60 second. Up to 5.0 µg mL-1 concentration of Cu(II), the complex of 5-Chlorosalicylaldehyde thiosemicarbazone with Cu(II) in butyl acetate follows Beer's law, with its maximum absorbance occurring at 380 nm. By employing the Jobs continuous variation method, the composition 1:1 has been determined for the Cu(II)-CSTSC complex, and this finding is further supported by the mole ratio method. The extracted complex remained stable for 72 hours. 5.47 x 10-3 µg cm-2 was determined to be Sandell's sensitivity, whereas 1.16 x 104 L mol-1 cm-1 was the molar absorptivity. Commercial and synthetic samples have been effectively analysed using this method. [ABSTRACT FROM AUTHOR]

The present study aims to characterize the direct UV-Vis spectrophotometric analysis of hexavalent chromium (CrVI) in aqueous solution. The effects of pH and the presence of different ions are evaluated. The results obtained show that at pH ≤ 6, Cr(VI) analysis must be carried out at 350 nm. The Beer-Lambert law is respected for a concentration lower than 100mg Cr(VI) L-1. At pH ≥ 8, the analysis must be performed at 372 nm. In this case, the linearity range of the standard curve does not exceed the concentration of 25 mg Cr(VI) L-1. In the pH range 6

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Analysis of the pathology image is important to diagnose cancer of lung, breast and stomach. Segmenting the nucleus is a key step for quantitative analysis, and has significance to the pathology researches and computer aided diagnosis systems. The inconsistency of colour, fuzzy boundary of nucleus and overlapping of cells are the universally acknowledged challenges. To solve these problems, the difference between the inside and outside of nucleus is enhanced by obtaining the distribution of the haematoxylin based on Lambert–Beer's law and the optical characteristics of stains. An inferior encoder, which is supervised by the inferior decoder, is proposed to extract the deep features of the distribution of stains. And these features are fed into the primary encoder to improve the accuracy of segmentation. To relieve the problem that some nuclei are segmented as background because the deep feature is inapparent, dynamic convolution is introduced into the encoders. The experiments show that the proposed model can segment the nucleus in the pathological images more precisely than the compared models. The Dice similarity coefficient (DSC) and panoptic quality (PQ) are 0.810 and 0.512, respectively. [ABSTRACT FROM AUTHOR]

Non-invasive detection of hemoglobin (Hb) concentration is of great clinical value for health screening and intraoperative blood transfusion. However, the accuracy and stability of non-invasive detection still need to be improved to meet clinical requirement. This paper proposes a non-invasive Hb detection method using ensemble extreme learning machine (EELM) regression based on eight-wavelength PhotoPlethysmoGraphic (PPG) signals. Firstly, a mathematical model for non-invasive Hb detection based on the Beer-Lambert law is established. Secondly, the captured eight-channel PPG signals are denoised and fifty-six feature values are extracted according to the derived mathematical model. Thirdly, a recursive feature elimination (RFE) algorithm is used to select the features that contribute most to the Hb prediction. Finally, a regression model is built by integrating several independent ELM models to improve prediction stability and accuracy. Experiments conducted on 249 clinical data points (199 cases as the training dataset and 50 cases as the test dataset) evaluate the proposed method, achieving a root mean square error (RMSE) of 1.72 g/dL and a Pearson correlation coefficient (PCC) of 0.76 (p < 0.01) between predicted and reference values. The results demonstrate that the proposed non-invasive Hb detection method exhibits a strong correlation with traditional invasive methods, suggesting its potential for non-invasive detection of Hb concentration. [ABSTRACT FROM AUTHOR]

Underwater wireless optical communication (UWOC) in harbor waters can facilitate real-time monitoring underwater instruments for environmental monitoring, underwater inspection, and maintenance tasks. This study delves into the complex dynamics of UWOC in four distinct harbor waters. The research employs Monte Carlo method incorporated with Fournier–Forand scattering phase function for simulating photon transmission. Key parameters such as the Transmitted full divergence angle, received aperture, and Field of View (FOV) are meticulously evaluated for their impact on power loss and time delay spread. Notably, the normalized power loss and time delay spread are found to be more significantly affected by communication distance than water quality, and the traditional Beer–Lambert law is ineffective in harbor water. The power loss of Harbor II, III, and IV are found to be 14.00 dB, 31.59 dB, and 41.59 dB lower than that of Harbor I, and the time delay spread of Harbor II, III, and IV is 30.56%, 9.67%, and 0.49% times that of the Harbor I under certain conditions. In addition, increasing the received aperture and FOV, particularly over longer distance, make little contribution to reduce the power loss and mitigate the time delay spread. Based on the fixed transmitted full divergence angle, the most applicable received FOV range is 1–3.2 rad, and the most ideal received aperture is 0.15–0.4 m. Under these conditions, the variation in normalized power loss is less than 2 dB. Additionally, the time delay spread remains within the same order of magnitude with the attenuation length (AL) held constant. These conclusions hold substantial technical relevance for the engineering design of UWOC systems in harbor waters. [ABSTRACT FROM AUTHOR]

A new set of standalone parameterizations is presented for simulating the injection, evolution, and radiative forcing by stratospheric volcanic aerosols against an idealized Held-Suarez-Williamson atmospheric background in the Energy Exascale Earth System Model version 2. Sulfur dioxide (SO2) and ash are injected into the atmosphere with a specified profile in the vertical, and proceed to follow a simple exponential decay. The SO2 decay is modeled as a perfect conversion to a long-living sulfate aerosol which persists in the stratosphere. All three species are implemented as tracers in the model framework, and transported by the dynamical core's advection algorithm. The aerosols contribute simultaneously to a local heating of the stratosphere and cooling of the surface by a simple plane-parallel Beer-Lambert law applied on two zonally-symmetric radiation broadbands in the longwave and shortwave range. It is shown that the implementation parameters can be tuned to produce realistic temperature anomaly signatures of large volcanic events. In particular, results are shown for an ensemble of runs that mimic the volcanic eruption of Mt. Pinatubo in 1991. The design requires no coupling to microphysical subgrid-scale parameterizations, and thus approaches the computational affordability of prescribed-aerosol forcing strategies. The idealized simulations contain a single isolated volcanic event against a statistically uniform climate, where no background aerosols or other sources of externally-forced variability are present. This model configuration represents a simpler-to-understand tool for the development of climate source-to-impact attribution methods. [ABSTRACT FROM AUTHOR]

BACKGROUND: A large number of previous studies have confirmed that a high concentration of metabolites is significantly correlated with embryo quality and clinical outcome, and the theory of silencing embryo development indicates that normally developed embryos maintain a low level of material exchange with the outside world during in vitro culture, while embryos often show abnormal metabolic activity due to stress repair mechanism when DNA damage occurs. OBJECTIVE: To establish and verify an embryo quality prediction model based on the third-day 340 nm absorbance embryo cultures to provide the basis for a more objective and accurate embryo quality assessment. METHODS: 269 patients at the Nanxishan Hospital of Guangxi Zhuang Autonomous Region for in vitro fertilization and embryo transplantation from November 2019 to December 2021 were retrospectively analyzed. Among them, on day 3, 162 cases who had 873 optimal embryos and 214 high-quality blastocysts were included in the high-quality embryo group. On day 3, 107 cases who had 859 non-optimal embryos and 214 non-high-quality blastocysts were included in the non-high-quality embryo group. Lambert-beer law was used to screen out the characteristic wavelength with distinguishing degree between superior and non-superior embryos, analyze its correlation and influence trend with high-quality embryos, and establish the clinical prediction model and validation of absorbance for high-quality and non-high-quality embryos at this wavelength. RESULTS AND CONCLUSION: (1) There was a significant difference in absorbance between high-quality and non-high-quality embryos at 340 nm on day 3 (P < 0.001), and a negative correlation was found with the formation of high-quality embryos on day 3 (r=-0.486, P < 0.001). The absorbance of high-quality and non-high-quality blastocyst at 340 nm was significantly different (P < 0.05), and was negatively correlated with the formation of high-quality blastocyst (r=-0.642, P < 0.001). (2) The optimal cut-off value of absorbance at 340 nm between high-quality and non-high-quality embryos on day 3 was 0.235. The area under the curve was 0.799. Sensitivity was 62.9%. Specificity was 78.0%. Accuracy was 70.5%. The optimum cutoff value of high-quality and non-high-quality blastocysts of absorbance at 340 nm was 0.175. The area under the curve was 0.871. Sensitivity was 74.3%. Specificity was 89.1%. Accuracy was 82.2%. (3) Restricted cubic spline curve analysis showed that when the absorbance of the culture medium at 340 nm was greater than 0.221, there was a significant positive trend on the formation of non-high-quality embryos at day 3, and when the absorbance of the culture medium at 340 nm was greater than 0.160, there was a significant positive trend on the formation of non-high-quality blastocysts. (4) The clinical decision curve and clinical influence curve showed that the absorbance of the culture medium at 340 nm had the maximum clinical net benefit for the prediction models of high-quality embryos and high-quality blastocysts on the third day when the valve probability was 0.18-0.95 and 0.16-1.00, respectively, and the ratio of loss to gain within the valve probability range was always less than 1. It is proven that the prediction model has good efficacy in clinical applications. The results of embryo transfer showed that the absorbance of embryo culture medium at 340 nm in non-pregnant patients was significantly higher than that in clinical pregnancy, biochemical pregnancy and early abortion patients (P < 0.05). (5) The high-quality and non-high-quality embryo culture in 340 nm absorbance has a significant difference with correlation. The embryo quality prediction model has a certain clinical value and application effectiveness. The joint embryo morphology evaluation to a certain extent improves the objectivity and accuracy of embryo quality evaluation. [ABSTRACT FROM AUTHOR]

Background Analytical tests were conducted to investigate the use of N-bromosuccinimide (NBS) as an important, safe analytical reagent for the spectrophotometric detection of therapeutically significant dihydropyridine-based calcium antagonists (DHP), namely nifedipine (NIF) and amlodipine (AML), which have been demonstrated to possess antioxidant activity in vivo and to reduce the intracellular production of reactive oxygen species (ROS). Following the reaction of DHP and NBS in acidic media, the excess NBS was evaluated for the first time by its interaction with P-aminophenol (PAP), which produced a violet-colored product that was detected at 556 nm. Objective The analytical method was performed and validated since different variables disturbing the reaction (concentration of reagent, type and concentration of the selected acid, reaction time and the diluting solvents) were carefully studied and optimized. Methods The stoichiometry of the applied reaction was determined by Job's method of continuous variation. Monitoring of these drug dosage forms' content uniformity is a first tool or evidence for their efficacy and safety after their administration. Results Beer's law was obeyed in the concentration range 1.25–11.0 µg/mL for NIF and 1.25–10.0 µg/mL for AML. The calculated limit of detection (LODs) and limit of quantification (LOQs) for NIF and AML were 0.220, 0.155 µg/mL and 0.519, 0.735 µg/mL, respectively. The precision of the applied method was satisfactory; the RSDs did not exceed 2%. Two greenness assessment tools, the Green Analytical Procedure Index (GAPI) and Analytical Greenness Metric for Sample Preparation (AGREEprep) were used for measuring the environmental friendliness of the recommended method. Conclusion The micro-determinations of content uniformity for NIF and AML in their pharmaceutical dosage forms were extremely comparable with those from official and validated procedures. Highlights A validated indirect spectrophotometric method for accurate quantification of some 1,4-dihydropyridine drugs using NBS with the aid of PAP. Monitoring of NIF and AML dosage forms' content uniformity as a first tool or evidence for their efficacy and safety after their administration. Greenness evaluation tools, GAPI and AGREEprep, for measuring the environmental friendliness of the recommended method. [ABSTRACT FROM AUTHOR]

Background: Simulated computed tomography (CT) images allow for knowledge of the underlying ground truth and for easy variation of imaging conditions, making them ideal for testing and optimization of new applications or algorithms. However, simulating all processes that affect CT images can result in simulations that are demanding in terms of processing time and computer memory. Therefore, it is of interest to determine how much the simulation can be simplified while still achieving realistic results. Purpose: To develop a scanner‐specific CT simulation using physics‐based simulations for the position‐dependent effects and shift‐invariant image corruption methods for the detector effects. And to investigate the impact on image realism of introducing simplifications in the simulation process that lead to faster and less memory‐demanding simulations. Methods: To make the simulator realistic and scanner‐specific, the spatial resolution and noise characteristics, and the exposure‐to‐detector output relationship of a clinical CT system were determined. The simulator includes a finite focal spot size, raytracing of the digital phantom, gantry rotation during projection acquisition, and finite detector element size. Previously published spectral models were used to model the spectrum for the given tube voltage. The integrated energy at each element of the detector was calculated using the Beer–Lambert law. The resulting angular projections were subsequently corrupted by the detector modulation transfer function (MTF), and by addition of noise according to the noise power spectrum (NPS) and signal mean‐variance relationship, which were measured for different scanner settings. The simulated sinograms were reconstructed on the clinical CT system and compared to real CT images in terms of CT numbers, noise magnitude using the standard deviation, noise frequency content using the NPS, and spatial resolution using the MTF throughout the field of view (FOV). The CT numbers were validated using a multi‐energy CT phantom, the noise magnitude and frequency were validated with a water phantom, and the spatial resolution was validated with a tungsten wire. These metrics were compared at multiple scanner settings, and locations in the FOV. Once validated, the simulation was simplified by reducing the level of subsampling of the focal spot area, rotation and of detector pixel size, and the changes in MTFs were analyzed. Results: The average relative errors for spatial resolution within and across image slices, noise magnitude, and noise frequency content within and across slices were 3.4%, 3.3%, 4.9%, 3.9%, and 6.2%, respectively. The average absolute difference in CT numbers was 10.2 HU and the maximum was 22.5 HU. The simulation simplification showed that all subsampling can be avoided, except for angular, while the error in frequency at 10% MTF would be maximum 16.3%. Conclusion: The simulation of a scanner‐specific CT allows for the generation of realistic CT images by combining physics‐based simulations for the position‐dependent effects and image‐corruption methods for the shift‐invariant ones. Together with the available ground truth of the digital phantom, it results in a useful tool to perform quantitative analysis of reconstruction or post‐processing algorithms. Some simulation simplifications allow for reduced time and computer power requirements with minimal loss of realism. [ABSTRACT FROM AUTHOR]

This article discusses a home experiment kit designed for physics students to perform experiments at home during the COVID-19 pandemic. The focus of the experiment is to explain the phenomenon of a glue stick appearing white near a light source and turning orange towards the opposite side. The experiment involves constructing a homemade spectroscope, measuring the transmittance of different colored filters, and measuring the mean free paths for the glue at each filter wavelength. The results show that the transmittance of the glue stick strongly depends on the wavelength of the incident light, demonstrating selective transmission. The activity can be used to reinforce concepts related to the physical basis of the greenhouse effect and can be a substitute for campus lab activities in distance learning. [Extracted from the article]

The study was performed with a dual approach to develop and validate analytical method for poorly water soluble candesartan cilexetil by enhancing its solubility employing cosolvency technique. In order to enhance drug's solubility based on its solubility characteristics, phosphate buffer (pH 6.8):ethanol (95 % v/v) mixture at 90:10 proportion was used along with Tween 80 (1 % v/v). Solubility of candesartan cilexetil in phosphate buffer (pH 6.8) enhanced due to the addition of cosolvent ethanol and Tween 80. Developed method obeyed Beer-Lambert's law in the concentration range between 3-21 µg/ml. The regression coefficient at the wavelength 232 nm was 0.999. The analysis of tablets by the proposed method indicated a good correlation between estimated and labelled claims. Recovery studies showed that any small difference in drug concentration could be accurately determined. Low values of limit of detection and limit of quantitation indicated that the proposed method is sensitive, economic, accurate, precise, and robust for routine analysis of candesartan cilexetil in bulk and dosage forms. [ABSTRACT FROM AUTHOR]

One of the remarkable choices for active smart window technology is adopting a metal active layer via reversible metal electrodeposition (RME). As the metal layer efficiently blocks the solar energy gain, even a hundred-nanometer-thick scale, RME-based smart window has great attention. Recent developments are mainly focused on the various cases of electrolyte components and composition meeting technological standards. As metal nanostructures formed through the RME process involve plasmonic phenomena, advanced analysis, including plasmonic optics, which is beyond Beer–Lambert's law, should be considered. However, as there is a lack of debates on the plasmonic optics applied to RME smart window technology, as research is mainly conducted through an exhaustive process. In this paper, in order to provide insight into the RME-based smart window development and alleviate the unclear part of plasmonic optics applied to the field, finite-difference time-domain electromagnetic simulations are conducted. In total, two extremely low-quality (Cr) and high-quality (Mg) plasmonic materials based on a nanoparticle array are considered as a metal medium. In addition, optical effects caused by the metal active layer, electrolyte, and nanoparticle embedment are investigated in detail. Overall simulations suggest that the effective refractive index is a decisive factor in the performance of RME-based smart windows. [ABSTRACT FROM AUTHOR]

In photoelectron spectroscopy in a gas atmosphere, the charging of an insulator sample is relaxed (environmental charge compensation). Here, we show that the environmental charge compensation effect becomes more remarkable when the distance (d) between the sample and the aperture cone increases. The large d dependence can be attributed to that electron scattering is largely suppressed by the aperture cone with vacuum inside at small d values. Moreover, photoelectron intensities obtained at various d values were found to be reproduced by replacing d with d+do (do is a constant) in the Beer-Lambert law. The residual gas in the pre-lens is considered to be the cause of do. [ABSTRACT FROM AUTHOR]

Polymer‐based materials are of high potential for application as active materials in contemporary electronic gadgets. The functionality of such materials is highly dependent on their oxidation state and requires fine control during their synthesis. Owing to that, we have designed a cost‐effective, simple, portable, system for calibration and the detection of the optical and electrical properties of polyaniline loaded on a paper substrate using a smartphone‐based colorimetric sensor. The vapor phase polymerization technique was adopted for preparing polyaniline. Colorimetric measurements of polyaniline‐loaded papers were achieved by estimating the hue, saturation and value (HSV) color parameter values using an open‐source smartphone application called "Color Grab (Color Detection)" during synthesis at different time intervals. The proposed sensor relies on the principle of Beer–Lambert law. The rear camera of the smartphone acts as a sensor and captures the light signal from the samples and provides information to the colorimetric app. The colorimetric results showed a promising correlation between the color parameter values with their electrical properties. The optical absorbance results of all polyaniline‐loaded papers are also in accordance with the H parameter values. The proposed sensor can be used as a portable smartphone‐based point‐of‐care testing kit to bring in‐situ control during synthesis. Highlights: Conducting polymer on flexible cellulose substrate.Smartphone‐based visual colorimetric sensor.Biodegradable and environment‐friendly electronic material.Variation of electrical properties in terms of hue values.Cheap, portable sensor for point‐of‐care testing. [ABSTRACT FROM AUTHOR]

Plant sterols are used as a supplement or an additive to reduce LDL cholesterol. The poor dispersibility and instability of phytosterols are the main limitations of their application. So, we tried to overcome these problems through nanoencapsulation of them with colloidal natural RSs (SLNs) using an effective approach to achieve higher efficiency and less intrinsic coagulation. Phytosterols extracted from flax seeds oil with caffeine by a new method were encapsulated with a stable colloid of sheep fat and ostrich oil (1:2), soy lecithin, and glucose through co-sonicated coacervation. Characterization of the obtained SLNs was conducted using FTIR, UV–Vis, SEM, DLS, and GC analysis. The three–factor three–level Behnken design (BBD) was used to prioritize the factors affecting the coacervation process to optimize particle size and loading capacity of SLNs. Operational conditions were examined, revealing that the size of SLNs was below 100 nm, with a phytosterols content (EE %) of 85.46% with high positive zeta potential. The nanocapsules' anti-microbial activity and drug-release behavior were then evaluated using the CFU count method and Beer-Lambert's law, respectively. The controlled release of nanocapsules (below 20%) at ambient temperature has been tested. The stability of nano-encapsulated phytosterols was investigated for six months. All results show that this green optimal coacervation is a better way than conventional methods to produce stable SLNs for the nanoencapsulation of phytosterols. [ABSTRACT FROM AUTHOR]

Neutron radiation exposure is one of the main challenges faced during space missions. There is a critical need for advanced lightweight radiation shielding materials. Two-dimensional (2D) boron nitride nanoplatelets (BNNP) are excellent candidates for polymer matrix nanofillers due to their superior neutron shielding and thermal and mechanical properties. Furthermore, the 2D material anisotropic behavior unlocks the potential for composite property tailoring. This study fabricated ultra-lightweight lamellar BNNP foams (density 0.05 g cm–3 and 97.5% porous) via freeze-drying processing. The neutron shielding effectiveness or mass absorption coefficient of the BNNP foams with walls perpendicular to the direction of the radiation source was 14.47 cm2 g–1, while that of the foam with parallel configuration was only 8.51 cm2 g–1. The orientation-dependent neutron radiation shielding properties were modeled using the Beer-Lambert law for porous composite materials. The BNNP foam in this study has the potential to benefit advanced tailorable radiation shielding technologies for future aerospace missions. [ABSTRACT FROM AUTHOR]

Four sensitive and fast analytical approaches relied on ion pairing with eosin Y were built up and evaluated using spectroscopy for determination of Alcaftadine and Olopatadine hydrochloride with high sensitivity and selectivity. Two spectrofluorimetric techniques were employed to observe the quenching effect of Alcaftadine or Olopatadine hydrochloride on the intrinsic fluorescence of eosin Y in a 0.1 M acetate buffer solution at pH 3.8 and 3.3 for Alcaftadine and Olopatadine hydrochloride, respectively. Those methods are considered the first spectrofluorimetric methods for Alcaftadine and Olopatadine hydrochloride assay. The fluorescence quenching effect was linear with concentration ranging from 150 to 2000 and 200 to 2000 ng mL−1 for Alcaftadine and Olopatadine hydrochloride, respectively. In the two spectrophotometric techniques, the absorbance of the produced ion-pair was monitored at 548 and 547 nm in aqueous buffered solution at pH 3.8 and 3.3 for Alcaftadine and Olopatadine hydrochloride, respectively. Beer's law was obeyed in the concentrations range of 0.8–8.0 and 1.0–10.0 µg mL−1. The four techniques were evaluated in accordance with ICH requirements and were effectively used to analyze dosage forms with a high percent recovery. [ABSTRACT FROM AUTHOR]

This work showcases a novel optical setup for water sensing based on transmission (Tx) (%) and absorbance (Ab) (AU). Four different water samples examine the sensing ability of the proposed device. These samples consist of RO water, tap water, groundwater, and pond water. The setup details the Tx (%) and Ab (AU) from different water samples. The Tx (%) obtained from the RO water (RW), tap water (TW), groundwater (GW), and pond water (PW) are 51.71%, 49.63%, 47.24%, and 45.92%, respectively. Similarly, the water sample's Ab (AU) is 0.288 AU, 0.297 AU, 0.320 AU, and 0.336 AU, corresponding to RW, TW, GW, and PW respectively. A linear relationship between Tx (%) and wavelength reaching the degree (2) provides maximum R2 = 0.9313. Similarly, a linear relationship between Ab (AU) and wavelength corresponding to a degree (2) provides maximum R2 = 0.9999. Thus, the developed setup successfully provides information about the sensing features from different water samples. [ABSTRACT FROM AUTHOR]

Oximetry, capnography and pH measurement are a fundamental facet of safe and modern anaesthetic and intensive care practice. A good anaesthetist will not only use these techniques routinely but will also understand how they work and how this can affect clinical management of their patients. This educational article aims to demonstrate the principles underlying these techniques, their limitations and recent developments. [ABSTRACT FROM AUTHOR]

The parameters governing a water temperature model play a pivotal role in determining the uncertainties associated with the model's outcome. In this study, a two-dimensional (2D) hydrodynamic and water temperature coupling model is constructed, focusing on the Nuozhadu Reservoir situated along the Lancang River. Employing a single-factor analysis approach, the sensitivity of the thermal balance parameters and hydrodynamic parameters in the model is assessed. This study overcomes the shortcomings of previous sensitivity analyses of hydrodynamic parameters in reservoir water temperature models. The findings reveal that the attenuation parameters of light and Beer's law parameter exhibit minimal sensitivity to the vertical temperature structure. Conversely, radiation parameter A and radiation parameter B exert tenfold disparate influences on the surface and bottom temperatures of the reservoir. Among the hydrodynamic parameters considered, the horizontal viscosity factor shows no sensitivity to the vertical temperature structure, whereas the vertical viscosity factor serves as a crucial determinant, directly influencing the intensity of vertical temperature stratification. An increased vertical viscosity factor promotes heat exchange between the upper and lower water layers, thereby reducing the vertical temperature gradient and weakening stratification. Conversely, diminishing this factor intensifies stratification. Thus, when conducting water temperature simulations in high dams and large reservoirs, careful attention should be given to calibrating vertical viscosity factor. [ABSTRACT FROM AUTHOR]

A simple spectrophotometric method for the determination of folic acid in pharmaceutical dosage samples was developed. The method is based on the diazotization reaction of thiourea with sodium nitrite in acidic medium yielding diazonium compounds, which is then coupled with folic acid in basic medium and resulting in yellow coloured azo dyes. The Beer's Lamberts law is observed in the range 0.5-16.2 µg ml-1 at a maximum wavelength of 416 nm. Molar absorbtivity, Sandell's sensitivity, regression equation, detection limit and quantitation limit were found. This method successfully determined folate in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Objectives: The objective of present work was to develop and standardize UV-spectrophotometric method for estimation of Phenytoin in marketed formulation. Materials and method: UV-Spectrophotometric method was developed using 1 N NaOH as solvent. The developed method was standardized in terms of validation parameters such as simple, sensitive, precise, linear, accurate, robust, reproducible as per ICH Q2(R1) guidelines. For estimation of phenytoin in marketed formulation this newly developed method was successfully applied. Results: Phenytoin exhibits max at 218 nm and in the Beer's range 2 to 10 µg/ml Beer's law was obeyed. The limit of detection was found to be 1.71µg/ml and limit of quantification was found to be 5.20 µg/ml. Recovery of Phenytoin in marketed formulation was obtained in range of 100-106%. All the precision and repeatability results were observed within the accurate range less than 2%. Conclusion: The method was found to be simple, accurate, environment friendly, reproducible and marketed formulation of Phenytoin can be estimated. [ABSTRACT FROM AUTHOR]

Precision farming, a labor-saving and highly productive form of management, is gaining popularity as the number of farmers declines in comparison to the increasing global food demand. However, it requires more efficient crop phenology observation and growth monitoring. One measure is the leaf area index (LAI), which is essential for estimating biomass and yield, but its validation requires destructive field measurements. Thus, using ground and UAV observation data, this study developed a method for indirect LAI estimation based on relative light intensity under a rice canopy. Daily relative light intensity was observed under the canopy at several points in paddy fields, and a weekly plant survey was conducted to measure the plant length, above-ground biomass, and LAI. Furthermore, images from ground-based and UAV-based cameras were acquired to generate NDVI and the canopy height (CH), respectively. Using the canopy photosynthetic model derived from the Beer–Lambert law, the daily biomass was estimated by applying the weekly estimated LAI using CH and the observed light intensity data as input. The results demonstrate the possibility of quantitatively estimating the daily growth biomass of rice plants, including spatial variation. The near-real-time estimation method for rice biomass by integrating observation data at fields with numerical models can be applied to the management of major crops. [ABSTRACT FROM AUTHOR]

Conventional scintillator‐based X‐ray imaging typically captures the full spectral of X‐ray photons without distinguishing their energy. However, the absence of X‐ray spectral information often results in insufficient image contrast, particularly for substances possessing similar atomic numbers and densities. In this study, an innovative multi‐energy X‐ray linear‐array detector is presented that leverages side‐illuminated X‐ray scintillation using the emerging metal halide Cs3Cu2I5. The negligible self‐absorption characteristic not only improves the scintillation output but is also beneficial for improving the energy resolution for the side‐illuminated scintillation scenarios. By exploiting Beer's law, which governs the absorption of X‐ray photons with different energies, the incident X‐ray spectral can be reconstructed by analyzing the distribution of scintillation intensity when the scintillator is illuminated from the side. The relative error between the reconstructed and measured X‐ray spectral is < 5.63%. This method offers an additional energy‐resolving capability for X‐ray linear‐array detectors commonly used in computed tomography (CT) imaging setups, surpassing the capabilities of conventional energy‐integration approaches, all without requiring extra hardware components. A proof‐of‐concept multi‐energy CT imaging system featuring eight energy channels is successfully implemented. This study presents a simple and efficient strategy for achieving multi‐energy X‐ray detection and CT imaging based on emerging metal halides. [ABSTRACT FROM AUTHOR]

Expectations for high-resolution observations by very low Earth orbit (VLEO, below 300 km) satellites are growing. However, the density of atomic oxygen (AO) is much higher in VLEO than in LEO (300 km or higher), so severe degradation of materials is a concern due to high-flux AO collisions. To clarify the degradation, we developed and deployed the material degradation monitor (MDM) mission onboard the super-low altitude test satellite (SLATS). In the MDM, several materials were exposed to the environment at 160–560 km from 23 December 2017 to 1 October 2019 and observed optically by a CCD camera. In general, AO fluence is evaluated by measuring the volume or mass loss of a polyimide, but this was difficult to do because the samples could not be returned to the ground in this mission. This study evaluated AO fluences using the CCD images of a polyimide, Vespel. The sample had nine non-penetrating holes with different bottom-plate thicknesses and was monitored by the CCD while being illuminated by LED light from the back. The CCD images reveal the intensity of the light transmitted through the holes in the bottom plate. The erosion depths of the polyimide, corresponding to the AO fluences, can be evaluated from the pixel values at the hole positions on the images. Here, the correlation between the pixel values and thickness was investigated for pristine and AO-exposed Vespel samples using the MDM engineering models. The total green pixel values followed the Beer-Lambert law for the bottom-plate thicknesses, regardless of AO exposure. Applying the correlation to the MDM flight images, we found that the AO fluence increased significantly after the end of March 2019, finally reaching (6.5–9.8) × 1021 atoms/cm2. This optical imaging method would be useful for evaluating the AO effects on the other MDM samples and high AO fluences in future VLEO missions. • In MDM, 13 materials were exposed to LEO and VLEO and observed by a CCD camera. • A polyimide resin, Vespel, was included in the samples to evaluate AO fluences. • This study analyzed optical images of Vespel exposed to AO in ground and MDM. • AO fluences could be estimated using the images based on the Beer-Lambert law. • The final AO fluence was estimated to be (6.5–9.8) × 1021 atoms/cm2 at the MDM. [ABSTRACT FROM AUTHOR]