Beer's Law Research Articles

Application of 2-chlorobenzaldehyde thiocarbohydrazone as a chromogenic ligand for cadmium(II) detection and removal from water and food

BackgroundCadmium, a hazardous element, is indeed naturally present in the environment and can pose serious health risks to people exposed to it through air, food, or water. Exposure to cadmium has been linked to a range of health issues, including kidney, liver, and lung failure. MethodsVarious samples from different sources are analyzed for their cobalt(II) content by extraction followed by UV–visible spectrophotometry and compared with atomic absorption spectrophotometry. ResultsThe reagent 2-chlorobenzaldehyde thiocarbohydrazone forms yellow 1:2 [Cd(II)-2CBTCH] complex in ethylene chloridewhich was extracted from an acetate buffer (pH 5.8) and observed maximum absorbance at 420 nm. The molar absorptivity and Sandell's sensitivity of the complex was reported to be 0.7868 × 104 L mol−1 cm−1 and 0.01428 µg cm−2. The method obeys Beer's law in the range of 3.5–9.5 µg mL−1 of [Cd(II)-2CBTCH] complex, which indicates linearity between two variables. For five replicate determinations (n = 5), the standard deviation was 0.84 with the regression equations as y = 0.0661 x + 0.01 with R2 = 0.999 as the correlation coefficient. The relative standard deviation (% R.S.D.) was found to be 0.84. ConclusionThe method was effectively used in variety of foods and water samples and was evaluated its performance in terms of Student ‘t’ test and Variance ‘f’ test, which indicates the significance of the present method as an inter comparison of the experimental values using atomic absorption spectrophotometer.

Flotation kinetic tracking of sand contaminated with hydrocarbons: image analysis of pulp color changes in time

Hydrocarbon contamination in the environment represents a significant challenge. Soil remediation by flotation has been proposed as an effective approach to address this issue. This method entails the separation of hydrophobic compounds, such as soil hydrocarbons, by introducing air into a stirred reactor containing the soil pulp designated for remediation. Experiments were conducted using a 5 L Batch flotation cell to evaluate operating conditions. These experiments focused on obtaining flotation kinetics with different organic mixtures, including fine sands measuring under 150 µm. The experimental design encompassed airflow, hydrocarbon concentration, and surfactant dosage. The research utilized a diluted pulp (3% solids) with a high organic concentration (8 and 17 g/L). Flotation kinetics were measured by developing an innovative technique based on pulp colour and image processing software. This technique facilitated the tracking of concentration changes over time under Beer-Lambert's Law. Subsequently, the results were adjusted using kinetic models commonly employed in mineral flotation, including the First Order, Kelsall, and Klimpel models. This comprehensive analysis sought to elucidate the underlying phenomenology and assess the potential for industrial-scale implementation. The laboratory findings indicate the possibility of achieving recoveries of up to 86.9%, with a first-order kinetic constant of 0.73 (1/min). It is noteworthy that both the gas flow rate and the addition of surfactant exert substantial influence on this constant, consistent with the observed phenomenology of this study. Additionally, the research unveiled the impact of hydrocarbon concentration on kinetics, suggesting an additional mechanism governing hydrocarbon transport.

Spectrophotometric Determination of Amoxicillin Using New Organic Reagent <i>via</i> Different Analytical Methods

New and simple spectrophotometric method was applied for amoxicillin determination by oxidative coupling with an organic reagent 1-(4-aminophenyl)-3-(5-(4-nitrophenyl)-furan-2-yl)-yl)-prop-2-en-1-one (H) to form an orange colored dye with λmax of 490 nm. The molecular structure of the new compound H was characterized using spectral analysis including 1H-NMR, FTIR, Mass spectroscopy, and UV-visible. The concentration range of oxidative coupling obeyed Beer's law was 2–50 μg/mL, the correlation coefficient was 0.9995, molar absorptivity was 0.63 × 104 L/mol cm, and the detection limit was 0.189 μg/mL. The concentration range of flow injection obeyed Beer's law was 1–150 μg/mL, the correlation coefficient was 0.9994, molar absorptivity was 0.295 × 104 L/mol cm, and the detection limit was 0.407 μg/mL. The proposed method was successfully applied in pharmaceutical formulation for amoxicillin determination. The results showed that amoxicillin could be reacted with a new compound H in the alkaline medium in the presence of oxidative agent NaIO4 and automated by flow injection analysis. The proposed methods have the advantage of simple, fast, very sensitive, good precision and accuracy. The suggested technique was effectively used to estimate amoxicillin in both its pure form and pharmaceutical formulations.

Predicting monthly near-surface soil temperature from air temperature and the leaf area index

Soil temperature at the land surface (Tsoil) is a key variable for modeling processes that occur belowground. Although Tsoil is correlated to the near-surface air temperature (Tair), these values are often not equal. Evidence confirms that Tsoil – Tair (ΔT) varies by ecosystem in both positive and negative directions. The goal of this study was to calibrate a semi-empirical model to predict Tsoil from Tair and its interaction with the leaf area index (LAI) at a monthly timescale. The latter variable is introduced to quantify the reduction in solar radiation reaching the land surface using Beer-Lambert's Law with an extinction coefficient k = 0.55. Bootstrap distributions for the three unknown parameters in the model were optimized using monthly Tair and Tsoil measurements from 169 eddy covariance towers in the FLUXNET2015 dataset accompanied by LAI observations at 0.5-km2 resolution from the MODIS satellite. The optimized model had a mean bias error (MBE) of -0.08 °C and a root mean square error (RMSE) of 2.26 °C. When Tsoil was assumed equal to Tair (ΔT = 0), these metrics worsened to -1.51 °C and 4.09 °C, respectively. Data from the US National Ecological Network (MBE/RMSE = -0.51°/2.81 °C) and published global predictions of ΔT obtained with a machine learning algorithm (MBE/RMSE = 0.73°/1.76 °C) validated the optimized model at the global scale. The data confirmed that ΔT tends to be positive when Tair 〈 0 °C, and transitions to negative values when Tair 〉 0 °C and LAI is greater than 1.89. In the proposed model, LAI values close to 1.89 indicate a 37 % reduction in solar radiation (e − 1 in Beer-Lambert's Law). Overall, this work confirms that Tsoil ≠ Tair in most ecosystems and that ΔT is predominantly explained by LAI in non-freezing conditions. Re-calibration is recommended before applying the model in barren ecosystems, or at spatiotemporal scales different from those in this research.

Trace mercury in wate were measured by dispersion-liquid microextraction combined with spectrophotometry

An experimental method was developed for the determination of trace amounts of mercury by dispersion-liquid microextraction combined with spectrophotometry. Undea buffer medium of hydrochloric acid and sodium acetate at pH=4, mrcury ions in the water were extracted by dispersion-liquid microextraction at the wavelength of 410nm, carbon tetrachloride was used as an extractant, methanol was used as a dispersant, dithizone-methanol solution was used as a chelating agent, the optimum conditions for extraction were obtained, Carbon tetrachloride 70uL, methanol 0.75mL, dithizone methanol solution 200uL. Under the optimal conditions, Lambert-Beer's law was satisfied at concentrations of 0.1-20μg/L,the detection limit is 64.2ng /L, The correlation coefficient of the standard curve was R2 =0.9983, the relative deviation was about 4.64%. Three water samples were measured, the recoveries were 96.8%-109.2%.

A high-precision and wide-range pH monitoring system based on broadband cavity-enhanced absorption spectrum

A high-precision pH monitoring system over a wide pH range is introduced. The system comprises a cavity-enhancement module constructed by two high-reflectivity mirrors, a microfluidic pH sensing chip based on a binary-indicator membrane of Congo red and m-cresol purple, and a hyperspectral transmission module. This structure extends the effective absorption optical path of the sensing chip, significantly amplifying the spectral differences at various pH values. The spectrum of the transmitted light is recorded by a self-developed hyperspectral module and then converted to broadband cavity-enhanced absorption spectrum (BBCEAS) via the Beer-Lambert law. An artificial neural network (ANN) is employed to predict pH values of the solution. With such a design, this system exhibits a wide detecting range of 2 M [H+] − 2 M [OH–] (corresponding to pH −0.3–14.3) with a response time of about 120 s. The system can achieve a higher detection accuracy with root mean square error (RMSE) of 0.073, as compared to 0.137 without the cavity enhancement. The system also possesses good properties of repeatability, long-term stability, ion resistance, and organic corrosion resistance. These excellent properties make the proposed system a promising candidate technology for harsh environments, such as seawater acidification warning, chemical plant sewage monitoring, and biological sample detection.

Utility of N-Bromosuccinimide-Water Combination as a Green Reagents for a Validated Indirect Spectrophotometric Determination of Some Antihypertensive Drugs: An Application to Their Monitoring in Marketed Tablets and Capsules.

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. 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. 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. 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. 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. 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.

Leaf area index (LAI) and gap fraction. A discussion

Methodological aspects of estimating leaf area from gap fraction measurements are discussed. Instead of the common practice of linking in the Beer-Lambert law leaf area index and clumping factor together, the clumping factor and Ross-Nilson geometry function as two structure parameters should be combined into the effective geometry function, which considers both the leaf angle distribution and clumping/regularity of foliage in the expression of the gap fraction of a vegetation layer. Key words: leaf area index; foliage clumping; gap fraction; LAI-2000; G-function

Micro FT-IR spectroscopic measurements of CH4: Experimental calibration with high-pressure and high temperature optical cell (HPOC)

Fourier transform infrared spectroscopy (FTIR) is a prevalent nondestructive in situ analytical technique widely employed for the qualitative characterization of natural fluid inclusions. Presently, the quantitative determination of the temperature, pressure, and composition of natural inclusions stands as a pivotal challenge in the geological application of laser spectroscopy. Through the integration of the capillary high-pressure optical cell (HPOC) technique and Fourier transform infrared spectroscopy, infrared quantitative models for the C–H symmetric stretching band (v3) in the vapor phase of CH4 under varying temperature (40–200 °C) and pressure (20–500 bar) conditions are established for the first time. This accomplishment is achieved through fitting and calculation of infrared spectra. A linear quantitative relationship and the dynamic evolution of infrared spectral parameters (peak area, full width at half maximum, peak height ratio, and peak shifts) concerning temperature, pressure, and density are meticulously investigated. The findings reveal that the peak area and full width at half maximum exhibit an upward trend with increasing pressure and density, and are inversely proportional to temperature. The height ratio (P band/Q band, R band/Q band) experiences an increase as density escalates. Moreover, the CH4v3 band position shows a higher wavenumber shift with increasing temperature, while its position correlates negatively with pressure and density. Thus, this method demonstrates its applicability in deducing the PVT-x properties of CH4-bearing systems, including CH4-rich fluid inclusions, CH4 content within hydrocarbon inclusions, and experimental fluid investigations. In contrast to the Raman quantitative approach, the infrared quantitative formula can be universally adopted in any infrared laboratory owing to the quantitative theory (Beer–Lambert law) governing infrared absorption spectra. By collecting Raman spectra and infrared spectra of pure methane fluid inclusions from the central region of the Alps and subsequently calculating the results using two distinct quantitative methods for fluid inclusions, we have demonstrated the feasibility of applying infrared spectroscopy in natural fluid inclusion studies.

Improving Determination of Pigment Contents in Microalgae Suspension with Absorption Spectroscopy: Light Scattering Effect and Bouguer-Lambert-Beer Law.

The Bouguer-Lambert-Beer (BLB) law serves as the fundamental basis for the spectrophotometric determination of pigment content in microalgae. Although it has been observed that the applicability of the BLB law is compromised by the light scattering effect in microalgae suspensions, in-depth research concerning the relationship between the light scattering effect and the accuracy of spectrophotometric pigment determination remains scarce. We hypothesized that (1) the precision of spectrophotometric pigment content determination using the BLB law would diminish with increasing nonlinearity of absorbance, and (2) employing the modified version of the BLB (mBLB) law would yield superior performance. To assess our hypotheses, we cultivated Phaeodactylum tricornutum under varying illumination conditions and nitrogen supplies in controlled indoor experiments, resulting in suspensions with diverse pigment contents. Subsequently, P. tricornutum samples were diluted into subsamples, and spectral measurements were conducted using different combinations of biomass concentrations and path lengths. This was carried out to assess the applicability of the BLB law and the nonlinearity of absorbance. The chlorophyll a and fucoxanthin contents in the samples were analyzed via high-performance liquid chromatography (HPLC) and subsequently used in our modeling. Our findings confirm our hypotheses, showing that the modified BLB law outperforms the original BLB law in terms of the normalized root mean square error (NRMSE): 6.3% for chlorophyll a and 5.8% for fucoxanthin, compared to 8.5% and 7.9%, respectively.

Radiative transfer model and validation for infrared management optical properties of porous polymer materials incorporating impacts of micro-voids

In order to characterize the infrared (IR) radiation absorption and/or emission performances of functional porous polymers which claim to have healthcare functions due to IR excitation and emission by processing technologies, a radiative transfer model was constructed based on the principle of IR radiation, the Beer–Lambert law, the Fresnel’s formula and Planck’s law. The theoretical analysis was conducted for the IR management optical properties of the porous sheet polymer materials, including IR reflection, transmission, absorption and emission behaviours during the dynamic process of IR radiation. A modeling method for characterization and revealing of IR management optical properties and optical and thermal transfer behaviours of the reflection and transmission was then investigated from the structural parameters and the temperature rise characteristics of the porous sheet polymer materials during the dynamic IR radiation process. The model was validated by comparing the predicted values from the radiative transfer model with the measured values from the test results of the validation experiments of eight typical porous sheet polymers in an experimental setup. The model was modified by consideration of the influences of two types of micro-voids defects represented by the porosity of micro structure and the thickness compression ratio. The micro-voids defects factors were added to the structural parameters, and therefore the model was improved and the maximum prediction errors of the transmission and reflection surfaces were mostly less than 10%. The radiative transfer model provides the theoretical fundamentals for the evaluation and guidance of IR management optical performances for new products design, development, fabrication and processing in industrial application of functional porous polymers.

A NOVEL STABILITY INDICATING UV SPECTROSCOPIC METHOD FOR SIMULTANEOUS ESTIMATION OF AZELNIDIPINE AND CHLORTHALIDONE IN ITS PURE AND PHARMACEUTICAL DOSAGE FORM

An accurate, precise and simple stability indicating ultraviolet spectroscopic technique was developed to quantify azelnidipine and chlorthalidone, simultaneously was bulk and in combination by absorbance correction method. Ethanol (99.9 %) is used as the solvent in the method. The detection wavelength was found to be 275 nm for chlorthalidone, and 345 nm for azelnidipine. The methodology was validated concerning sensitivity, linearity, reproducibility, accuracy, ruggedness and robustness. Beer-Lamberts law was obeyed in the concentration from 3.2–80 µg mL-1 in case of azelnidipine and 5-125 µg mL-1 in case of chlorthalidone. Detection limits were obtained as 1.74 µg mL-1 for azelnidipine and 2.376 µg mL-1 for chlorthalidone. For azelnidipine, quantification limit was 5.272 µg mL-1, while for chlorthalidone it was 7.2 µg mL-1. Accelerated stability studies were carried out. Azelnidipine and chlorthalidone showed different degradation characteristics under acid, alkali, humidity, heats, and oxidized environment.

Segmentation of nucleus based on dynamic convolution and deep features of stain distribution

AbstractAnalysis 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.

Development of Visible Spectrophotometric Method and its Validation for Dolutegravir in Tablet Dosage Form

Objective: There are several methods for analyzing the same, however, they are time-consuming and costly. We created a new spectrophotometric method for determining Dolutegravir (DLT) in tablet dosage forms that is simple, accurate, and precise. We developed and validated a simple, accurate, and precise colorimetric method for the quantitative analysis of Dolutegravir in bulk and dosage form by ICH recommendations in this study. Methodology: There are several methods for analyzing the same, however, they are time-consuming and costly. We created a new spectrophotometric method for determining Dolutegravir (DLT) in tablet dosage forms that is simple, accurate, and precise. In methanol, the initial stock solution of Dolutegravir was prepared. The method is based on the formation of a blue color chromogen complex from Dolutegravir oxidation-reduction with Ferric chloride in the presence of potassium ferricyanide. Result: The color complex was measured at 710nm. Beers law was observedin the concentration range of 3.5-6.5μg/ml witha coefficient of correlation (R2) was 0.998. The system suitability criteria were found to be within the limits. The LOD and LOQ were found to be 0.91 and 2.47, indicating that the method is sensitive. Conclusion: The relative standard deviation (RSD) and percent recovery values were found to be satisfactory, indicating that the proposed method is suitable, accurate, and precise and that it can be used in routine analysis of Dolutegravir in tablet dosage forms, with relatively low-cost solvents.

Self-calibrated pulse oximetry algorithm based on photon pathlength change and the application in human freedivers.

Pulse oximetry estimates the arterial oxygen saturation of hemoglobin () based on relative changes in light intensity at the cardiac frequency. Commercial pulse oximeters require empirical calibration on healthy volunteers, resulting in limited accuracy at low oxygen levels. An accurate, self-calibrated method for estimating is needed to improve patient monitoring and diagnosis. Given the challenges of calibration at low levels, we pursued the creation of a self-calibrated algorithm that can effectively estimate across its full range. Our primary objective was to design and validate our calibration-free method using data collected from human subjects. We developed an algorithm based on diffuse optical spectroscopy measurements of cardiac pulses and the modified Beer-Lambert law (mBLL). Recognizing that the photon mean pathlength () varies with related absorption changes, our algorithm aligns/fits the normalized (across wavelengths) obtained from optical measurements with its analytical representation. We tested the algorithm with human freedivers performing breath-hold dives. A continuous-wave near-infrared spectroscopy probe was attached to their foreheads, and an arterial cannula was inserted in the radial artery to collect arterial blood samples at different stages of the dive. These samples provided ground-truth via a blood gas analyzer, enabling us to evaluate the accuracy of estimation derived from the NIRS measurement using our self-calibrated algorithm. The self-calibrated algorithm significantly outperformed the conventional method (mBLL with a constant ratio) for estimation through the diving period. Analyzing 23 ground-truth data points ranging from 41% to 100%, the average absolute difference between the estimated and the ground truth is for our algorithm, significantly lower than the observed with the conventional approach. By factoring in the variations in the spectral shape of relative to , our self-calibrated algorithm enables accurate estimation, even in subjects with low levels.

Evaluation of atomic oxygen fluences by analyzing transmitted light images of polyimide obtained at SLATS/MDM

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.

Effect of Light Intensity on Photosynthesis in Aquatic Plants in Australia

Purpose: The aim of the study was to investigate the Effect of Light Intensity on Photosynthesis in Aquatic Plants in Australia.
 Methodology: The study adopted a desktop methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library
 Findings: In the study examining the impact of light intensity on photosynthesis in Australian aquatic plants, key findings emerged. It was evident that light intensity played a crucial role, with higher light levels in shallower waters leading to increased photosynthesis rates. This underscored the significance of light as a primary determinant of photosynthesis in these ecosystems. Additionally, the study highlighted the impressive adaptability of Australian aquatic plants, some of which employed unique photo protective mechanisms to prevent photo inhibition under varying light conditions.
 Unique Contribution to Theory, Practice and Policy: Theory of Liebig's Law of the Minimum, Theory of The Beer-Lambert Law and Optimal Foraging Theory may be used to anchor future studies on the Effect of Light Intensity on Photosynthesis in Aquatic Plants in Australia. Develop practical guidelines for growers to optimize light conditions for maximum photosynthetic efficiency. Advocate for policies that recognize the significance of aquatic plants in maintaining healthy aquatic ecosystems. Promote the conservation and restoration of natural habitats for aquatic plants, especially in areas threatened by pollution or habitat destruction.

Methods Development and Validation for the Estimation of Pioglitazone HCl in Bulk and Formulations by UV Spectroscopy and FTIR

The use of spectroscopic analysis, particularly UV spectrophotometer, is a simple and essential technique for bulk drug estimation, formulation studies, and compatibility assessments of drugs with various excipients. In the pharmaceutical industry, various analytical instruments, including Fourier transform infrared spectroscopy (FTIR), are employed for investigating drug-excipient interactions that can impact the stability of active pharmaceutical ingredients. This study aimed to develop a UV spectrophotometric method for the analysis of Pioglitazone hydrochloride in phosphate buffer (pH 7.4) and methanolic solution, assessing its linearity and compliance with Beer's Law. Furthermore, we aimed to use FTIR to characterize potential interactions between Pioglitazone and common pharmaceutical excipients, such as Guar Gum, Chitosan, and Sodium Alginate. Standard solutions of Pioglitazone were prepared in phosphate buffer (pH 7.4) and methanol. UV spectrophotometer was conducted to determine the maximum absorption wavelength. Calibration curves were constructed to evaluate linearity and adherence to Beer's Law. FTIR analyses were performed to investigate drug-excipient interactions by examining the functional groups. In phosphate buffer (pH 7.4), the maximum absorption wavelength for Pioglitazone hydrochloride was 268 nm. The calibration curve for Pioglitazone in phosphate buffer (pH 7.4) demonstrated linearity in the concentration range of 1–20 µg/ml, with a correlation coefficient of 0.998. In methanol, the maximum absorption wavelength for Pioglitazone hydrochloride was found to be 272 nm. The calibration curve in methanol exhibited linearity in the range of 1–20 µg/ml, with a correlation coefficient of 0.999. FTIR analysis revealed potential drug-excipient interactions, particularly in the case of Guar Gum, Chitosan, and Sodium Alginate, suggesting the formation of stable hydrogen bonds. The developed UV spectrophotometric method for Pioglitazone analysis is a reliable, cost-effective, and reproducible approach, making it a valuable tool for drug development and quality control. Additionally, the FTIR characterization confirmed interactions between Pioglitazone and common pharmaceutical excipients, enhancing our understanding of formulation compatibility.

A Modified Beer–Lambert–Bouguer Law for Nonrandom Distributions and Its Application in Gap Probability Calculations for Heterogeneous Canopies

AbstractThe three‐dimensional (3D) structure of vegetation canopy strongly influence the absorption and reflection of radiation at the land surface. The gap probability is one primary indicator of the canopy structure. For homogeneous canopies, where the plant elements are distributed completely randomly and statistically independent, the gap probability can be modeled with the Beer–Lambert–Bouguer law. However, this method is not suitable for nonrandom distributions. A physically based and computationally efficient algorithm is developed to address this limitation, by introducing the pair correlation function to describe the nonrandom distribution pattern. Pair correlation function is based on the distribution of distances of pairs of points, and can therefore describe random, clumped, or regular distribution patterns, and detect mixed patterns at different scales. In this paper, we take tree crown as the basic structure element, and apply the new method to calculate the gap probability. The simulations agree well with results obtained by the ray casting method for various distribution patterns. The results show that horizontal distribution of trees is one of the key factors impacts the gap probability. For the case when different patterns coexist on various scales, we can ignore the distribution pattern at larger scale, and focus on the pattern at smaller scale. When zenith angel is large, the azimuthal dependency of the gap probability should be noted.

Spectroscopic study of aqueous solutions of fullerene C60 mono-derivatives

Current spectral study of aqueous solutions of N-substituted fullerene C60 mono-derivatives of amino acid potassium salts showed that their solutions obey the Bouguer–Lambert–Beer law. On the basis of circular dichroism data, the optical activity was discovered not only for adducts with chiral amino acids but also for those with achiral molecules.