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Titanium dioxide (Titania) nanoparticle-coated biochar derived through co-pyrolysis of COVID-19 waste face mask (WFM) and Moringa oleifera seed cake (MO) provides an effective way to alleviate toxic metal in wastewater. This study investigates the effects of Biochar/titania photocatalyst preparation, characterization, and its photoreduction of Cr(VI). The morphological and functional modifications in the catalyst were identified using X-Ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet spectrophotometer, surface area analysis, and Raman spectrophotometer, respectively. The influencing parameters, namely, pH, photocatalyst dosage, initial pollutant concentration, and visible light irradiation time, have been investigated. The findings reveal that the Cr(VI) reduction by the photocatalyst was highly facilitated by photocatalytic process. The prepared photocatalyst shows higher and faster reduction rate of Cr(VI) and also improves the catalyst stability. The photoreduction of Cr(VI) ensembles well with pseudo-first order kinetics. At 180 min of reaction time, maximum Cr(VI) reduction of 98.65% was achieved at pH 2, 0.3 g/L catalyst dosage, and 10 ppm initial concentration, respectively. The synthesized photocatalyst shows excellent recycling performance up to 7 times, and these studies proved that the prepared catalyst is cost-effective and efficiently employed for removing pollutants.

Long-term, 21st century ground-based ozone measurements are crucial to study the recovery of stratospheric ozone as well as the trends of tropospheric ozone. This study is performed in the context of the LOTUS (Long-term Ozone Trends and Uncertainties in the Stratosphere) and TOAR-II (Tropospheric Ozone Assessment Report, phase II) initiatives. Within LOTUS, we want to know why different trends have been observed by different ground-based measurements at Lauder. In TOAR-II, intercomparison studies among the different ground-based datasets are needed to evaluate their quality and relevance for trend studies. To achieve these goals, we perform an intercomparison study of total column ozone and its vertical distribution among the ground-based measurement instruments available at the Lauder station from 2000 to 2022, which are a Fourier transform infrared (FTIR) spectrometer, a Dobson spectrophotometer, a UV2 (ultraviolet double monochromator), a microwave radiometer (MWR), ozonesondes, and a stratospheric lidar. Because only the latter two provide high-vertical-resolution profiles, the vertical ozone distribution is validated using partial columns, defined to provide independent information: one tropospheric column and three stratospheric columns. Because FTIR provides total columns and vertical information covering all partial columns as well as high temporal sampling, the intercomparisons (bias, scatter, and drift) are analyzed using FTIR as the reference. Very good agreement between the FTIR and Dobson (FTIR and UV2) total column ozone records is apparent in the high Pearson correlation of 0.97 (0.93), low biases of −3 % (−2 %), and 2 % (3 %) dispersions, which are within the respective systematic and random uncertainties. The small observed drifts 0.4 % (0.3 %) per decade are “non-significant” (or rather a low certainty in a 95 % confidence interval) and show good stability of the three ozone total column series at Lauder. In the troposphere we find a small bias of −1.9 % with the ozonesondes but a larger one (+10.7 %) with Umkehr, which can be explained by the low degrees of freedom for signal (0.5) of Umkehr in the troposphere. However, no significant drift is found among the three instruments in the troposphere, which proves their relevance for trend studies within TOAR-II. The negative bias observed in total columns is confirmed by negative biases in all stratospheric columns for all instruments with respect to FTIR (between −1.2 % and −6.8 %). This, confirmed by the total column biases, points to a 2 %–3 % underestimation of the infrared spectroscopic line intensities. Nevertheless, the dispersion between FTIR and all techniques is typically within 5 % for the stratospheric partial columns, in close agreement with the given random uncertainty budgets. We observe no significant drift in the stratosphere between ozonesondes and FTIR for all partial columns, with ozonesonde trends being less negative than in LOTUS (Godin-Beekmann et al., 2022, further referred to as the LOTUS22). The only significant drift in the lower-stratospheric columns is obtained between FTIR and Umkehr, as was already found in LOTUS22. Two significant positive drifts are observed in the middle stratosphere (2 % and 3 % per decade) with lidar and MWR, respectively, while two significant negative drifts are observed in the upper stratosphere (−3 % and −4 % per decade) with Umkehr and lidar, respectively. While remaining drifts are still present, our study explains roughly half of the differences in observed trends in LOTUS22 by the different sampling, vertical sensitivity, or time periods and gaps. In addition, the FTIR data in the present work have been improved since LOTUS22, reducing the differences in the upper-stratospheric and tropospheric trends. This shows the necessity for continuous review and improvement of the measurement and retrieval processes. This study also reflects the importance of super sites such as Lauder for cross-validating the long-term ozone measurements. Our study demonstrated that well-harmonized, optimized, well-characterized instruments that show very good agreement in terms of bias, dispersion, and correlation are capable of detecting trends that agree within their respective measurement uncertainties.

The spectrophotometer has been used for decades to measure the density of bacterial populations as the turbidity expressed as optical density–OD. However, the OD alone is an unreliable metric and is only proportionately accurate to cell titers to about an OD of 0.1. The relationship between OD and cell titer depends on the configuration of the spectrophotometer, the length of the light path through the culture, the size of the bacterial cells, and the cell culture density. We demonstrate the importance of plate reader calibration to identify the exact relationship between OD and cells/mL. We use four bacterial genera and two sizes of micro-titer plates (96-well and 384-well) to show that the cell/ml per unit OD depends heavily on the bacterial cell size and plate size. We applied our calibration curve to real growth curve data and conclude the cells/mL–rather than OD–is a metric that can be used to directly compare results across experiments, labs, instruments, and species.

The characterization of aqueous sugar solutions using optical techniques offers a non-invasive, rapid, and reagent-free approach for concentration monitoring in both analytical and environmental contexts. In this study, aqueous D-glucose solutions at concentrations of 0.1, 0.2, 10, 20, and 40 g/mL were analyzed using an ultraviolet–visible–near-infrared spectrophotometer across the 200–1020 nm wavelength range. Although glucose exhibits inherently low absorbance in this spectral domain due to the absence of strong chromophoric groups, measurable trends were observed—particularly in the ultraviolet region below 400 nm—consistent with theoretical expectations based on the Beer–Lambert law. Absorbance intensity increased consistently with glucose concentration, and while no sharp absorbance peaks were detected, subtle spectral variations encoded sufficient information to enable computational modeling. A feed forward artificial neural network was trained on the full spectral dataset and demonstrated high predictive accuracy, achieving a correlation coefficient exceeding 0.98. These findings underscore the potential of integrating ultraviolet–visible spectroscopy with machine learning techniques for real-time, label-free detection of glucose and similar analytes. The approach not only supports the development of fast and accurate monitoring systems in clinical and industrial settings but also lays the groundwork for future research involving more complex sugar matrices and environmentally relevant applications.

Nanotechnology is an emerging field of science. The base of nanotechnology is nanoparticles. The size of nanoparticles ranges from 1 to 100 nm. The nanoparticles are classified into different classes such as inorganic nanoparticles, organic nanoparticles, ceramic nanoparticles and carbon base nanoparticles. The inorganic nanoparticles are further classified into metal nanoparticles and metal oxide nanoparticles.similarly carbon base nanoparticles classified into Fullerene, Carbon nanotubes, Graphene, Carbon nanofiber and carbon black Nanoparticles are also classified on the basis of dimension such as one dimension nanoparticles, two-dimension nanoparticles and three-dimension nanoparticles. The nanoparticles are synthesized by using two approaches like top-down approach and bottom-up approach. In this review chemical, physical and green synthesis of nanoparticles is reported. The synthesized nanoparticles are synthesized using different qualitative and quantitative techniques. The Qualitative techniques include Fourier Transform Infrared Spectroscopy (FT-IR), UV-Vis spectrophotometry, Scanning electron microscope (SEM), X.ray diffraction (XRD) and Atomic Force Microscopy (AFM). The Quantitative techniques include Transmission Electron Microscopy (TEM), Annular Dark-Field Imaging (HAADF) and Intracranial pressure (ICP). The nanoparticles have different application which is reported in this review.

Water quality monitoring is an essential component of water quality management for water utilities for managing the drinking water supply. Online UV-Vis spectrophotometers are becoming popular choices for online water quality monitoring and process control, as they are reagent free, do not require sample pre-treatments and can provide continuous measurements. The advantages of the online UV-Vis sensors are that they can capture events and allow quicker responses to water quality changes compared to conventional water quality monitoring. This review summarizes the applications of online UV-Vis spectrophotometers for drinking water quality management in the last two decades. Water quality measurements can be performed directly using the built-in generic algorithms of the online UV-Vis instruments, including absorbance at 254 nm (UV254), colour, dissolved organic carbon (DOC), total organic carbon (TOC), turbidity and nitrate. To enhance the usability of this technique by providing a higher level of operations intelligence, the UV-Vis spectra combined with chemometrics approach offers simplicity, flexibility and applicability. The use of anomaly detection and an early warning was also discussed for drinking water quality monitoring at the source or in the distribution system. As most of the online UV-Vis instruments studies in the drinking water field were conducted at the laboratory- and pilot-scale, future work is needed for industrial-scale evaluation with ab appropriate validation methodology. Issues and potential solutions associated with online instruments for water quality monitoring have been provided. Current technique development outcomes indicate that future research and development work is needed for the integration of early warnings and real-time water treatment process control systems using the online UV-Vis spectrophotometers as part of the water quality management system.

The negative consequences of Substandard and falsified (SF) medicines are widely documented nowadays and there is still an urgent need to find them in more efficient ways. Several screening tools have been developed for this purpose recently. In this study, three screening tools were used on 292 samples of ciprofloxacin and metronidazole collected in Cameroon. Each sample was then analyzed by HPLC and disintegration tests. Seven additional samples from the nitro-imidazole (secnidazole, ornidazole, tinidazole) and the fluoroquinolone (levofloxacin, ofloxacin, norfloxacin, moxifloxacin) families were analyzed to mimic falsified medicines. Placebo samples that contained only inert excipients were also tested to mimic falsified samples without active pharmaceutical ingredient (API). The three screening tools implemented were: a simplified visual inspection checklist, a low-cost handheld near infrared (NIR) spectrophotometer and paper analytical devices (PADs). Overall, 61.1% of the samples that failed disintegration and assay tests also failed the visual inspection checklist test. For the handheld NIR, one-class classifier models were built to detect the presence of ciprofloxacin and metronidazole, respectively. The APIs were correctly identified in all the samples with sensitivities and specificities of 100%. However, the importance of a representative and up-to-date spectral database was underlined by comparing models built with different calibration set spanning different variability spaces. The PADs were used only on ciprofloxacin samples and detected the API in all samples in which the presence of ciprofloxacin was confirmed by HPLC. However, these PADs were not specific to ciprofloxacin since they reacted like ciprofloxacin to other fluoroquinolone compounds. The advantages and drawbacks of each screening tool were highlighted. They are promising means in the frame of early detection of SF medicines and they can increase the speed of decision about SF medicines in the context of pharmaceutical post-marketing surveillance.

Until recently, the classic approach to mineral exploration studies was to bring the field samples/drill cores collected during field studies to the laboratory, followed by laborious analysis procedures to generate the analytical data. This is very expensive, time-consuming, and difficult for exploring vast areas. However, rapid technological advances in field-portable analytical instruments, such as portable visible and near-infrared spectrophotometers, gamma-ray spectrometer, pXRF, pXRD, pLIBS, and µRaman spectrometer, have changed this scenario completely and increased their on-site applications in mineral exploration studies. LED fluorimeter is a potential portable tool in the hydrogeochemical prospecting studies of uranium. These instruments are currently providing direct, rapid, on-site, real-time, non-destructive, cost-effective identification, and determination of target elements, indicator minerals and pathfinder elements in rock, ore, soil, sediment, and water samples. These portable analytical instruments are currently helping to obtain accurate chemical and mineralogical information directly in the field with minimal or no sample preparation and providing decision-making support during fieldwork, as well as during drilling operations in several successful mineral exploration programs. In this article, the developments in these portable devices, and their contributions in the platinum group elements (PGE), rare earth elements (REE), gold, base metals, and lithium exploration studies both on land and on the ocean bed, have been summarized with examples.

The solid-state electrolytes have attractive properties for electrochromic (EC) devices and battery industries. Li + ion is the most applied and investigated carrier ion in this field together with less commonly ions Mg 2+ , Na + H + and Al 3+ . In this study, we have investigated Al 3+ solid electrolytes for WO 3 based EC devices as alternative to Li + ions. We have fabricated a series of AlSiO x thin films by applying different target powers of 0–15 W by magnetron sputtering method. The resulting films were characterized by Grazing incidence X-ray diffraction, atomic force microscopy, scanning electron microscopy, energy disperse spectroscopy, ultraviolet–visible-infrared spectrophotometer, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy (EIS). All samples showed high transparency in the visible range (~ 90%) while the transparency decreased about 10% in the near infrared region. Analysis of EIS data by Kramers–Kronig and Voigt models showed that some of the films have good ionic conductivity. The ionic conductivities of films grown with 10 W, 13 W and 15 W Al target powers were 1.54 × 10 –6 , 5.68 × 10 –7 and 2.72 × 10 –8 S/cm, respectively. The results indicate that AlSiO x solid electrolytes are promising for EC applications.

Background. The present in vitro study evaluated the camouflage effect of two treatments for white spot lesions (WSLs): remineralization with Mi Paste Plus© (GC Europe N.V.) and remineralization combined with a Scotchbond Multi-Purpose© (3M ESPE 2015) adhesive layer. Additionally, the study assessed the color stability of the treatments when exposed to a staining agent, such as coffee. Methods. Sixty extracted anterior and posterior teeth were preserved in saline solution and divided into two groups. Artificial WSLs were created using 37% orthophosphoric acid for 1 minute. Both groups underwent daily 6-hour remineralization treatments with Mi Paste Plus© for 14 days. In the second group, a thin adhesive layer was applied after remineralization. Color analysis was performed using an MHT SpectroShade Micro spectrophotometer at baseline (T1 ), after remineralization (T2 ), after adhesive application for group 2 (TR), and after immersion in coffee for 24 hours (T3 ). Color differences (ΔE) between healthy tissue and WSLs were assessed, with ΔE≤3.3 considered clinically acceptable. Data were analyzed using STATA 17 (P≤0.05). Results. ΔE analysis showed a statistically significant improvement in the camouflage effect in the adhesive-treated group (TR) compared to remineralization alone (T2 ). After coffee exposure (T3 ), ΔE values increased significantly in both groups, with higher values observed in the adhesive-treated group. Intragroup analyses indicated significant differences between T2 and T3 , as well as TR and T3 . Conclusion. The application of an adhesive system can be considered a valid option to improve the aesthetic outcome of a remineralization treatment; however, this approach carries the risk of resin staining over time.