Optimal Wavelength Research Articles

Identifying Optimal Wavelengths from Visible–Near-Infrared Spectroscopy Using Metaheuristic Algorithms to Assess Peanut Seed Viability

Peanuts, owing to their composition of complex carbohydrates, plant protein, unsaturated fatty acids, and essential minerals (magnesium, iron, zinc, and potassium), hold significant potential as a vital component of the human diet. Additionally, their low water requirements and nitrogen fixation capacity make them an appropriate choice for cultivation in adverse environmental conditions. The germination ability of seeds profoundly impacts the final yield of the crop; assessing seed viability is of extreme importance. Conventional methods for assessing seed viability and germination are both time-consuming and costly. To address these challenges, this study investigated Visible–Near-Infrared Spectroscopy (Vis/NIR) in the wavelength range of 500–1030 nm as a nondestructive and rapid method to determine the viability of two varieties of peanut seeds: North Carolina-2 (NC-2) and Spanish flower (Florispan). The study subjected the seeds to three levels of artificial aging through heat treatment, involving incubation in a controlled environment at a relative humidity of 85% and a temperature of 50 °C over 24 h intervals. The absorbance spectra noise was significantly mitigated and corrected to a large extent by combining the Savitzky–Golay (SG) and multiplicative scatter correction (MSC) methods. To identify the optimal wavelengths for seed viability assessment, a range of metaheuristic algorithms were employed, including world competitive contest (WCC), league championship algorithm (LCA), genetics (GA), particle swarm optimization (PSO), ant colony optimization (ACO), imperialist competitive algorithm (ICA), learning automata (LA), heat transfer optimization (HTS), forest optimization (FOA), discrete symbiotic organisms search (DSOS), and cuckoo optimization (CUK). These algorithms offer powerful optimization capabilities for effectively extracting relevant wavelength information from spectral data. Results revealed that all the algorithms demonstrated remarkable accuracy in predicting the allometric coefficient of seeds, achieving correlation coefficients exceeding 0.985 and errors below 0.0036, respectively. In terms of execution time, the ICA (2.3635 s) and LCA (44.9389 s) algorithms exhibited the most and least efficient performance, respectively. Conversely, the FOA and the LCA algorithms excelled in identifying the least number of optimal wavelengths (10 wavelengths). Subsequently, the seeds were classified based on the wavelengths selected via the FOA (10 wavelengths) and (DSOS (16 wavelengths) methods, in conjunction with logistic regression (LR), decision tree (DT), multilayer perceptron (MP), support vector machine (SVM), k-nearest neighbor (K-NN), and naive Bayes (NB) classifiers. The DSOS–DT and FOA–MP methods demonstrated the highest accuracy, yielding values of 0.993 and 0.983, respectively. Conversely, the DSOS–LR and DSOS–KNN methods obtained the lowest accuracy, with values of 0.958 and 0.961, respectively. Overall, our findings demonstrated that Vis/NIR spectroscopy, coupled with variable selection algorithms and learning methods, presents a suitable and nondestructive approach for detecting seed viability.

A selective dispersive liquid-liquid micro-extraction technique for trace level pollutants enrichment of pharmaceutical residues from hospital wastewaters followed by liquid chromatographic analysis

In this study a dispersive liquid-liquid micro-extraction (DLLME) method was utilized for extraction of trace pharmaceuticals in wastewater samples. Factors influencing the extraction performances were tested and accordingly 900 µL dichloroethane as the extraction solvent, 1400 µL acetonitirle as dispersive solvent, 10 min extraction time at 4000 rpm centrifugation, and pH 5 were found optimum. Acetonitrile and 0.2% formic acid in water were used as eluent. The column temperature was maintained at 25 °C and the optimum detection wavelengths of 273 nm for sulfamethoxazole and 280 nm for ciprofloxacin were used. For both the analytes, the coefficients of determinations (r2) were found to vary from 0.9989 to 0.9997, confirming good linearity in the concentration range of 0.005-100 µg mL-1 for sulfamethoxazole and 0.01-100 µg mL-1 for ciprofloxacin. The LOD and LOQ were in the range of 0.78-1.58 ng mL-1 and 2.24-5.28 ng mL-1, respectively; the RSDs were 0.41-3.21% for intra-day precision and 0.37-6.44% for inter-day precision. The concentrations of the three pharmaceuticals determined ranged from 0.76-1.53 μg mL-1 in the wastewater samples collected from Black Lion Hospital. However, ciprofloxacin and doxycycline were not detected and only low concentration of sulfamethoxazole was detected in the wastewater samples collected from Menelik II Hospital.
 KEY WORDS: Antibiotics, DLLME, Dispersive solvent, Hospital wastewater
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 27-42. DOI: https://dx.doi.org/10.4314/bcse.v38i1.3

A fluorescent probe based on carbon quantum dots with spectral selectivity for sensitive detection of Cr(VI) and Hg(II) in environmental waters

In this paper, fluorescent carbon dots were prepared by hydrothermal method using 3,5-dihydroxybenzoic acid and l-Arginine as precursors. The synthesized CDs have excitation-dependent emission with emission peaks at 354 nm and 460 nm, corresponding to the optimal excitation wavelengths of 295 nm and 330 nm, respectively. CDs have good dispersion and resistance to photobleaching in aqueous solution, and can maintain stable fluorescence in highly concentrated salt environment. Based on the inner filter effect, Cr(VI) with strong absorption can shield the excitation light of CDs at 295 nm and absorb the emission fluorescence at 354 nm simultaneously. Due to the intermolecular electrostatic interaction, Hg(II) can coordinate with CDs surface groups and cause static quenching, which significantly reduces the fluorescence intensity of CDs emitted at 460 nm. The linear ranges were 0.1–2 μM and 0.4–5 μM for Cr(VI) and Hg(II) detection, respectively, and limits of detection were 0.024 μM and 0.084 μM. Additionally, the probe was successfully applied to tap water and lake water samples. With high sensitivity and spectral selectivity, this sensing strategy realized the detection of two heavy metal ions by a single fluorescent probe, demonstrating its great potential in the field of environmental metal analysis.

Elemental analysis and quantification method development & validation of stigmasterol in Malaxis acuminata-A vanishing orchid

Orchids are highly valued for their therapeutic properties. Malaxis acuminata (vernacular name: Jeevak), is a vanishing orchid that has mystical healing potential. Wavelength dispersive X-ray fluorescence (WD-XRF) spectroscopy was employed to conduct elemental analysis of this orchid plant. Elements Potassium (K), Calcium (Ca), Phosphorus (P), Magnesium (Mg), Silicon (Si), Sulphur (S), Chlorine (Cl), Aluminium (Al), Iron (Fe), Ruthenium (Ru), Manganese (Mn), Zinc (Zn), Rubidium (Rb), Titanium (Ti), Copper (Cu), Strontium (Sr), and Nickel (Ni) are documented quantitatively and qualitatively. These elements are pivotal in shaping the plant's medicinal potential. Likewise, a multitude of organic molecules within the plant exhibit therapeutic potential. Stigmasterol is one such molecule, esteemed for its remarkable properties and a spectrum of health benefits. The present investigation additionally encompassed the establishment and validation of a methodology for the precise quantification of stigmasterol within the petroleum ether extract, utilizing high-performance thin-layer chromatography (HPTLC). The bioactive compound was isolated through the utilization of a specific mobile phase of toluene: ethyl acetate: methanol (8:1.5:0.5, v/v/v), and an optimal wavelength of 580 nanometers was ascertained. Validation of this method was conducted by the guidelines established by the International Council for Harmonisation (ICH). The calibration range for the stigmasterol was established to span from 400 to 3600 micrograms per spot (μg/spot). The Rf (retention factor) value for the separation of stigmasterol was determined to be 0.56 ± 0.04. The limit of detection (LOD) and limit of quantification (LOQ) were established at 15.954 nanograms per spot (ng/spot) and 48.344 ng/spot, respectively. Linearity (r2 0.999), accuracy (98.14– 99.21 %), and RSD of precision (1.953–2.984). specificity and robustness were evaluated by ICH guidelines. The stigmasterol content was 634.6 ± 3.28 μg/ml, which demonstrates promising results. This method exhibits substantial applicability in pharmaceuticals, nutraceuticals, food, and health-related sectors.

Humidity sensor using numerical simulation and electrospun Pd/TEA/PVA on a U-shaped fiber sensor

In this study, we proposed a novel humidity sensor for environmental monitoring and biomedicine applications. The sensing layer of the U-shaped fiber sensor was fabricated by electrospinning. Used COMSOL Multiphysics software simulation to determine the optimal wavelength and transmission loss by finding the best U-shaped fiber radius between 1 and 2 mm. Results showed at 1550 nm, a 1.5 mm radius had better transmission loss. In the humidity experiment, the U-shaped fiber transmission loss significantly increased from 20% to 70% RH. The average change was 0.222 dB/%RH with a sensitivity of 0.004 dB/%RH and linearity of 0.940, indicating good linearity and reproducibility. Furthermore, the electrospun Pd/Triethanolamine (TEA) wire material improved the sensor layer's sensitivity and stability to humidity, enhancing the humidity measurement response.

H2/CO production via high temperature electrolysis of H2O/CO2 coupling with solar spectral splitting at a tunable cut-off wavelength

Solar driven CO2/H2O splitting is a promising path for large-scale and long-term solar energy conversion and storage. In this work, a thermodynamic model of solar driven high-temperature CO2/H2O electrolysis was established, with the full solar spectrum split at a tunable cut-off wavelength for meeting the electrical and thermal energy demands of the process at a high efficiency. Compared with the system without spectral splitting, the solar-to-H2 efficiency can be significantly improved from 36.0 % to 45.5 % by introducing spectral splitting. Besides, the optimal electrolysis temperature can be largely lowered, from 1623 K to 1323 K due to the significant reduction of the solar radiation input for electricity generation. The exergy efficiency of CO2 electrolysis was shown to be higher than that of H2O electrolysis due to the higher molar exergy of CO compared to H2, although the first-law efficiency of H2O electrolysis is higher at Tele < ∼1200 K. A high concentration ratio of the solar-thermal process can lead to both high solar-to-fuel efficiency and high optimal electrolysis temperature because of the reduction of reradiation loss. The electrolysis temperature and the use of excessive CO2/H2O were shown to have an important effect on both the efficiency and the optimal cut-off wavelength because they are closely related with the thermal and electrical energy demands of the whole process. The optimal cut-off wavelength can be as low as 540 nm at electrolysis temperature of 1873 K (Tele = 1873 K) and excessive H2O coefficient of 6 (r = 6), and increases to the working limit of the photovoltaic material (900 nm in this work) as the electrolysis temperature and excessive coefficient decrease to Tele < 1023 K and r < 2.

Fast Calculation on Atmospheric Rayleigh Scattering Extinction Optical Depth for Day/Night Band Radiative Transfer Model With Periodic Lunar Illumination

AbstractRayleigh scattering effect inspired by tiny atmospheric molecules generates significant extinction at relatively short wavelength, such as Day/Night Band (DNB) covering visible (VIS, 0.4–0.76 μm) and near‐infrared (NIR, 0.76–1.0 μm) wavelengths. This salient extinction effect coupled with periodic changes in lunar illumination and wide DNB will further lead to increased complexity in nocturnal fast radiative transfer model (RTM) calculation of DNB. For these reasons, this study is aimed at developing a precise and robust fast calculation method on Rayleigh scattering extinction optical depth (RayOD) for pertinent fast RTM calculation of DNB. Firstly, we coupled the lunar spectral irradiance model and the parameterized Rayleigh scattering extinction calculation module into a RTM for forward simulations. Moreover, we find that the errors in DNB‐averaged RayOD calculated from the classical fast algorithm from RTTOV (Radiative Transfer for TOVS) of training the DNB instrument coefficients (about 20% of relative error in reflectance) and the parameterization method using the central wavelength of DNB (about 5%) are too large to be tolerable in fast RTM. Finally, to address this issue, we skillfully conceptualize a new equivalent optimal central wavelength algorithm to retrieve a dynamically wavelength in DNB using observation scattering and lunar phase angles for rapidly calculating DNB‐averaged RayOD. The relative errors in simulated reflectance from coupled RTM aforementioned are subtle nuances, which are about 10−5∼10−6 order of magnitude. Besides, this robust algorithm can also correct the relative error of about 1% at dark surface caused by periodic changes in lunar illumination.

Rapid assessment of residual solvent content in the TEGDN dual-base propellants by near-infrared reflectance spectroscopy

Excessive residual solvent (RS) levels in triethyleneglycol dinitrate (TEGDN) dual-base propellants can significantly impair combustion performance. This work aimed to develop a rapid and accurate model for detecting the RS content in the TEGDN dual-base propellants using near-infrared (NIR) spectroscopy in the reflectance mode. The optimal wavelength range for modelling, spanning from 1124.9−1230.2 nm and 1335.5–1527.5 nm, was identified based on absorption peaks characteristic of TEGDN dual-base propellant samples and RS. To enhance the quality of the data, we determined optimal window sizes for pre-processing methods: derivative pre-processing and Savitzky-Golay (S-G) smoothing pre-processing. After evaluating the performance of different pre-treatment methods, we found that the model employing multiple scattering corrections (MSC) in conjunction with first-order derivative (FD) pre-processing demonstrated superior results. The partial least squares (PLS) method was used to build the RS model with an optimal number of factors of 6. For the developed RS model, the root mean square error of calibration (RMSEC) and the root mean square error of cross-validation (RMSECV) were 0.019 and 0.024, respectively. The determination coefficient of calibration (Rc2) and the determination coefficient of cross-validation (Rcv2) were 0.968 and 0.952, respectively. In assessing the validation set using the developed model, we observed a root mean square error of prediction (RMSEP) of 0.025 and a determination coefficient of prediction (Rp2) of 0.958. Importantly, the relative error between the predicted values obtained through the NIR method and the measured values from the reference method consistently remained below 2 % under all circumstances. Consequently, the NIR-based RS model developed in this study offers a rapid and efficient means of detecting RS content in TEGDN dual-base propellants, facilitating judgment regarding the qualification of RS content.

Investigation of the optimal wavelength for hybrid LD/LED-UWOC links with MIMO techniques

Investigation of the optimal wavelength for hybrid LD/LED-UWOC links with MIMO techniques

Fluorescent carbon dots synthesized by waste wind turbine blade for photocatalytic degradation.

Developing novel waste recycling strategies has become a feasible solution to overcome environmental pollution. In this work, a method of using waste wind turbine blade (WTB) as a carbon source to synthesize blue fluorescent carbon dots (B-CDs) by hydrothermal treatment is proposed. B-CDs are spherical and have an average particle size of 5.2nm. The surface is rich in C-O, C=O, -CH3 , and N-H bond functional groups, containing five elements: C, O, N, Si, and Ca. The optimal emission wavelength of B-CDs is 463 nm, corresponding to an excitation wavelength of 380 nm. Notably, a relatively high quantum yield of 29.9% and a utilization rate of 40% were obtained. In addition, B-CDs can serve as a photocatalyst to degrade methylene blue dye, with a degradation efficiency of 64% under 40-min irradiation conditions. The presence of holes has a significant influence on the degradation process.

Multivariate optimization of hyperspectral imaging for adulteration detection of ground beef: Towards the development of generic algorithms to predict adulterated ground beef and for digital sorting

Due to its nutritional value, and taste, minced beef meat (MBM) is highly valuable therefore is susceptible to economically motivated adulteration. High-throughput adulteration detection methods are required to guarantee the authenticity and safety of the MBM. Hyperspectral imaging (HSI) in the 400–1000 nm spectral range, in tandem with multivariate analysis, was evaluated to demonstrate the feasibility of developing generic models to detect minced beef meat adulterated with other types of meats. Partial least squares regression (PLSR) method, the ensemble Monte Carlo variable selection method (EMCVS), a range of spectral pre-treatments, and combinations of any two of them were evaluated to predict the amount of MBM in each prepared sample scanned. The beef prediction model was developed using data from MBM adulterated with minced chicken and turkey meats and validated with data from MBM adulterated with pork meat at adulteration levels ranging from 0 to 51% at approximately 3% increments. Good prediction results were obtained using the EMCVS, on the asymmetric least squares (AsLs) + Standard Normal variate (SNV) pre-treated reflectance spectra (Rp2 0.96, RMSEP 2.9% and RPD 5.4) with 23 selected wavelengths. An independent set of MBM samples adulterated with lamb and duck meat were then prepared similarly at concentrations ranging from 3 to 21% to test the developed method. Good results were obtained in the full range (R2p 0.94, RMSEp 3.92%, RPDp 3.83) and excellent prediction results (R2p 0.95, RMSEp 2.78%, RPDp 5.29) were obtained with 9 optimum wavelengths (484, 508, 593, 596, 602, 736, 739, 924 and 960 nm). PLS discriminant analysis (PLS-DA), the EMCVS and spectral pre-treatments were used to discriminate MBM from other adulterants and achieved almost perfect classification for calibration, cross-validation, and prediction using 12 selected spectral bands. This study developed a high-throughput generic minced meat adulteration prediction and discrimination method based on selected spectral bands that can be used to further develop low-cost portable sensors for the digital sorting of adulterated MBM, and demonstrates the feasibility to develop generic models to detect minced beef meat adulterated with other types of meat.

The completely renewed and upgraded neutron reflectometer at the TU Delft Reactor Institute

The horizontal time-of-flight neutron reflectometer at the reactor of the Delft University of Technology, The Netherlands, has been completely renewed, relocated, and upgraded and allows for the study of air/liquid, solid/liquid, and solid/air interfaces. Innovations in the redesign include (i) a completely flexible double disk chopper system allowing to choose the optimal wavelength resolution with exchangeable neutron guide sections between the chopper disks to increase intensity, (ii) a movable second diaphragm just before the sample position to better control the beam footprint on the sample and effectively decrease counting times, and (iii) guides along the entire flight path of the neutron reflectometer. The performance of the renewed reflectometer is illustrated with measurements of hydrogen sensing materials.

Comparison of UV-LED treatments at 255 and 281 nm in continuous-flow on bacterial inactivation, quality, nutrients and electrical efficiency in beverages

Ultraviolet light emitting diodes (UV-LEDs) have emerged as an alternative UV source. We compared the treatment of coconut water (CW), blue lemonade (BL) and ascorbic acid (AA) solution at 255 and 281 nm UV-LEDs in continuous-flow in terms of bacterial inactivation and effects on physical, quality and nutritional parameters and electrical efficiency. A 5-log10 reduction of Escherichia coli was achieved in CW and BL at both wavelengths. At similar fluence levels, a decrease in absorption coefficient (CW and BL), ascorbic acid and antioxidants (CW) was observed at both wavelengths. An increase in colour lightness of BL was observed at 281 nm. Treatment with 281 nm was more electrically efficient at achieving a 5-log10 reduction in beverages compared to 255 nm. This was confirmed in AA solution where 281 nm showed less photo-oxidation compared to 255 nm. Use of UV-LEDs allows for selection of optimal wavelengths to achieve higher microbial and electrical efficiency while maintaining product quality.

Construction and experimental verification of optimal expansion wavelength (OEW) inertia criterion based on three-channel wide-spectrum temperature measurement technology

The optimal expansion wavelength (OEW) is a specific parameter that achieves the best approximation effect of the Taylor series on the temperature measurement integral equation. In the approximation of temperature measurement equations with different spectral emissivity, the OEW exhibits a high degree of stability, which is called the inertia of OEW to spectral emissivity. With the existence of this property, the approximation equation and temperature solution can be obtained by blackbody OEW in the case of unknown spectral emissivity. This serves as a fundamental basis for temperature measurement of targets with unknown spectral emissivity. To address the ambiguity in defining the inertia of OEW in this technique, a criterion for determining OEW inertia is proposed and verified by experiments. In this study, a parameter that quantitatively describes the approximation effects of the OEW is defined. By combining the discussion on the intersection of the approximation data and the reduced-channel signal under different approximation effects, an evaluation criterion for the OEW inertia is established through the definition of the confidence interval of the approximation effect. To macroscopically validate the correctness of the OEW inertia criterion, a simulation study is conducted to investigate the impact of the amplitude and FWHM of the spectral response function (SRF) on OEW inertia, based on this criterion. The correctness of the simulation results is confirmed through comparative experiments of temperature measurements on different SRF detectors, further demonstrating the correctness of the OEW inertia criterion.

Discriminating Stellera chamaejasme in alpine grasslands using UAV hyperspectral imagery and multivariate analysis

Stellera chamaejasme is highly invasive and causes a significant threat to alpine grassland on the Qinghai-Tibet Plateau. It is important to determine its distribution pattern in order to stem the rapid invasion of this toxic weed. In the present study, strategies for mapping S. chamaejasme based on UAV Resonon hyperspectral imaging were assessed in combination with dimension reduction, clustering and ordination analysis, and spectral separability measurement. Field spectrometry analysis showed that the hierarchical procedure of Kruskal-Wallis test and Dunn’s post hoc test, CART and JM distance can efficiently select the minimum optimal wavelengths for S. chamaejasme discrimination and considerably reduce the dimensions of hyperspectral imagery. DCA and RDA ordination revealed that S. chamaejasme identification at the species level is difficult even using hyperspectral feature bands. The reaggregating of TWINSPAN ecological communities based on the criterion of JM distance &amp;gt; 1.9 can result in spectrally delineated S. chamaejasme communities and the co-existing species community. Applying three algorithms of MLC, RF, and SVM, the performance of S. chamaejasme classification based on JM-TWINSPAN schemes was significantly improved compared to that based on TWINSPAN schemes. Of these, RF and JM-TWINSPAN achieved the best classification result (OA = 91.00%, Kappa = 0.83, AD = 14.0%, and QD = 1.2%). The result indicates that the promising accuracy can be achieved in accurate mapping of S. chamaejasme by a multivariate approach, which combines ecological analysis and separability measurement with image classification.

Analytical solution to incident angle quasi-phase-matching engineering for second harmonic generation in a periodic-poled lithium niobate crystal

Phase matching or quasi-phase matching (QPM) is of significant importance to the conversion efficiency of second harmonic generation (SHG) in artificial nonlinear crystals like lithium niobate (LN) crystal or microstructured nonlinear crystals like periodic-poled lithium niobate (PPLN) crystals. In this paper, we propose and show that the incident angle of pump laser light can be harnessed as an alternative versatile tool to engineer QPM for high-efficiency SHG in a PPLN crystal, in addition to conventional means of period adjusting or temperature tuning. A rigorous model is established and analytical solution of the nonlinear conversion efficiency under the small and large signal approximation theory is obtained at different incident angles. The variation of phase mismatching and walk-off length with incident angle or incident wavelength are also explored. Numerical simulations for a PPLN crystal with first order QPM structure are used to confirm our theoretical predictions based on the exact analytical solution of the general large-signal theory. The results show that the narrow-band tunable SHG output covers a range of 532 nm–552.8 nm at the ideal incident angle from 0° to 90°. This theoretical scheme, fully considering the reflection and transmission at the air-crystal interface, would offer an efficient theoretical system to evaluate the nonlinear frequency conversion and help to obtain the maximum SHG conversion efficiency by selecting an optimum incident wavelength and incident angle in a specially designed PPLN crystal, which would be very helpful for the design of tunable narrow-band pulse nanosecond, picosecond, and femtosecond laser devices via PPLN and other microstructured LN crystals.

Hyperbranched Polyborosiloxanes: Non-traditional Luminescent Polymers with Red Delayed Fluorescence.

Non-traditional fluorescent polymers have attracted significant attention for their excellent biocompatibility and diverse applications. However, designing and preparing non-traditional fluorescent polymers that simultaneously possess long emission wavelengths and long fluorescence lifetime remains challenging. In this study, a series of novel hyperbranched polyborosiloxanes (P1-P4) were synthesized. As the electron density increases on the monomer diol, the optimal emission wavelengths of the P1-P4 polymers gradually red-shift to 510, 570, 575, and 640 nm, respectively. In particular, P4 not only exhibits red emission but also demonstrates delayed fluorescence with a lifetime of 9.73 μs and the lowest critical cluster concentration (1.76 mg/mL). The experimental results and theoretical calculations revealed that the synergistic effect of dual heteroatom-induced electron delocalization and through-space O⋅⋅⋅O and O⋅⋅⋅N interaction was the key factor contributing to the red-light emission with delayed fluorescence. Additionally, these polymers showed excellent potential in dual-information encryption. This study provides a universal design strategy for the development of unconventional fluorescent polymers with both delayed fluorescence and long-wavelength emission.

Hyperbranched Polyborosiloxanes: Non‐traditional Luminescent Polymers with Red Delayed Fluorescence

AbstractNon‐traditional fluorescent polymers have attracted significant attention for their excellent biocompatibility and diverse applications. However, designing and preparing non‐traditional fluorescent polymers that simultaneously possess long emission wavelengths and long fluorescence lifetime remains challenging. In this study, a series of novel hyperbranched polyborosiloxanes (P1–P4) were synthesized. As the electron density increases on the monomer diol, the optimal emission wavelengths of the P1–P4 polymers gradually red‐shift to 510, 570, 575, and 640 nm, respectively. In particular, P4 not only exhibits red emission but also demonstrates delayed fluorescence with a lifetime of 9.73 μs and the lowest critical cluster concentration (1.76 mg/mL). The experimental results and theoretical calculations revealed that the synergistic effect of dual heteroatom‐induced electron delocalization and through‐space O⋅⋅⋅O and O⋅⋅⋅N interaction was the key factor contributing to the red‐light emission with delayed fluorescence. Additionally, these polymers showed excellent potential in dual‐information encryption. This study provides a universal design strategy for the development of unconventional fluorescent polymers with both delayed fluorescence and long‐wavelength emission.

The quality monitoring of paracetamol medicament using a noninvasive microwave sensor

Environmental conditions, including temperature, humidity, and light, can impact the quality of drugs. Microwave-based approaches offer a fast and cost-effective way to detect quality variations, providing an alternative to traditional techniques in the pharmaceutical and cosmetic industries. This article proposes the use of a microwave sensor for monitoring the quality of pharmaceutical drugs at distinct temperature levels. A small planar sensor based on three hexagonal split ring resonators (TH-SRR) is fabricated. The design is manufactured on an FR-4 dielectric substrate. The sensor is tested on a 1000 mg paracetamol tablet, at temperatures ranging from 40 to 80 ^circC. The Variation in the permittivity that characterizes product degradation is translated into a shift in the frequency of the scattering matrix elements. To validate the microwave approach, drug quality is examined with the laser-induced breakdown spectroscopy (LIBS) technique, an optical emission laser used for both qualitative and quantitative investigations of elements contained in a sample. The existing elements are classified using the National Institute of Standards and Technology (NIST) database and categorized according to their spectral line wavelengths. The experiments show the presence of optimal wavelength values for carbon (C), hydrogen (H), nitrogen (N), and oxygen (O) at 247.92 nm, 656.49 nm, 244.23 nm, and 777.48 nm, respectively. The microwave experimental results show a shift frequency of approximately 1 MHz on average when the tablet is heated at 80 ^circC for 15 min. Meanwhile, the LIBS measurement shows a remarkable shift in terms of intensity of approximately 8884 and 812 for carbon and hydrogen, respectively. Understanding how paracetamol dries under high temperatures and improving the process settings of the microwave sensor are investigated and assessed in this work.

Performance evaluation of photonic crystal fibre sensor for controlled drugs detection: a simulation approach

This study proposes a simple and efficient Photonic Crystal Fibre sensor design for the detection of controlled drugs such as cocaine, amphetamine, and ketamine. The design uses a pentagonal core hole and circular cladding air holes in 2 layers, made of fused silica substrate. The sensing performance of the proposed PCF design is evaluated using COMSOL Multiphysics and Finite Element Method, operating in the visible and infrared range from 0.4 to 3.2 μm. Results show that the proposed PCF design achieves high relative sensitivities of 99.55%, 99.75%, and 99.99% for cocaine, amphetamine, and ketamine, respectively, at the optimum wavelength of 0.4 μm. Additionally, the design is robust, showcasing minimal variations in relative sensitivities with changes in pitch distance, air hole diameter, and core hole length. These findings make the proposed PCF design a promising candidate for practical controlled drug sensing.