Similar Substances Research Articles

Development of the headspace gas chromatography-tandem mass spectrometry method for ethylene oxide and ethylene chlorohydrin residue in medical devices.

Ethylene oxide (EO) sterilization is commonly employed for the sterilization of medical devices and has a very high market share. However, EO and its metabolite ethylene chlorohydrin (ECH) are toxic to humans. In compliance with the classification and residue limits of medical devices defined by ISO 10993-7, our study established two extraction methods for the testing of EO and ECH. The first method involves simulated-use extraction using water as the extraction solvent. While the second, exhaustive extraction, directly extracts sample through headspace sampling analysis. Gas chromatography-tandem mass spectrometry in multiple reaction monitoring mode was utilized, requiring only 16 min. Then, the developed method was applied to assess 10 commercially available medical devices sterilized by EO. In simulated-use extraction, calibration curves were evaluated in the range of 1-100 and 5-500 μg for EO and ECH, respectively (r > 0.999). Inter-day recoveries ranged from 85.0% to 95.2% and from 94.8% to 102.4%. In exhaustive extraction, calibration curves spanned 0.5-50 and 2-200 μg for EO and ECH, respectively (r > 0.999). Inter-day recoveries ranged from 101.6% to 102.1% for EO and from 98.1% to 102.2% for ECH. After analysis of the 10 commercially available medical devices, two cotton swabs were found to have ECH of 35.1 and 28.4μg per device, and four medical devices were found to have EO with concentration below the limit of quantification. Meanwhile, we found that the EO internal standard (propylene oxide) recommended by ISO 10993-7 had interference problems with other similar substances and was not suitable as an internal standard for EO. This study offers a sensitive and straightforward analytical approach to EO and ECH residues in a variety of medical devices. In addition, the results show that the EO or ECH content of these types of medical devices in our study falls below the regulatory limits, therefore instilling confidence among consumers regarding their safe use.

High-Resolution Terahertz Spectroscopy for MedicalDiagnostics.

The metabolomics-based approach to diagnostics and therapy monitoring is a fast-emerging trend in modern medicine. Terahertz nonstationary spectroscopy based on the induction and disintegration of freely decaying polarization in the gas mixture during the interaction of radiation with molecules at resonance frequencies is a high-sensitivity method for studying multicomponent gas mixtures, which is promising for identifying metabolites in the thermal decomposition products of biological samples. The paper presents the results of the application of high-resolution terahertz spectroscopy to the study of biological samples taken from patients with certain diseases (pathologically changed tissues of ear-nose-throat organs and similar pathologic tissues formed in other life support systems) to search for characteristic sets of metabolites characterizing the pathology. The world's first measurements of the spectra of pathologic samples of cysts, formed in different life support systems, were carried out, which made it possible to identify similar substances in tissues having the same pathology.

Determination of terpene-based VOCs emitted from pine wood using NIR spectroscopy

ABSTRACT In the search for a quick and less labor-intensive method for determining terpene emissions of high emitting wood like Pinus sylvestris, this study utilized near-infrared spectroscopy (NIR) combined with multivariate analysis methods and compared it to the standard measurement method according to the EN 16516 standard. The spectra were measured on the surface of solid-wood samples and correlated with the simultaneously determined air concentrations of terpenes. For α-pinene and 3-carene, prediction models were created using partial least squares regression (PLSR). Both work with determination coefficients of 0.77 and a Root Mean Square Error of Prediction (RMSEP) of 12% of the maximum emissions achievable in this study. A model based on the sum of the two terpenes was built and tested to determine the predictive capability of multiple similar substances simultaneously from the NIR recording. The model performs slightly worse, with a determination coefficient of 0.71 and RMSEP of 13%. Despite continuous expansion of the datasets for multiple models, no better metrics were achieved, likely because of the heterogeneous structure of wood when scanning a solid-wood surface. Systematic deviations were observed in particularly low reference ranges, which may indicate non-linearity in the relationship between terpenes and the NIR signal.

Cryptic species complex shows population-dependent, rather than lineage-dependent tolerance to a neonicotinoid

Cryptic species are rarely considered in ecotoxicology, resulting in misleading outcomes when using a single morphospecies that encompasses multiple cryptic species. This oversight contributes to the lack of reproducibility in ecotoxicological experiments and promotes unreliable extrapolations. The important question of ecological differentiation and the sensitivity of cryptic species is rarely tackled, leaving a substantial knowledge gap regarding the vulnerability of individual cryptic species within species complexes. In times of agricultural intensification and the frequent use of pesticides, there is an urgent need for a better understanding of the vulnerability of species complexes and possible differences in adaptive processes. We used the cryptic species complex of the aquatic amphipod Gammarus roeselii, which comprises at least 13 genetic mtDNA lineages and spans from small-scale endemic lineages in Greece to a large-scale widely distributed lineage in central Europe. We exposed eleven populations belonging to four lineages to the neonicotinoid thiacloprid in an acute toxicity assay. We recorded various environmental variables in each habitat to assess the potential pre-exposure of the populations to contaminants. Our results showed that the populations differed up to 4-fold in their tolerances. The lineage identity had a rather minor influence, suggesting that the cryptic species complex G. roeselii does not differ significantly in tolerance to the neonicotinoid thiacloprid. However, the observed population differentiation implies that recent pre-exposure to thiacloprid (or similar substances) or general habitat contamination has triggered adaptive processes. Though, the extent to which these mechanisms are equally triggered in all lineages needs to be addressed in the future. Our study provides two key findings: Firstly, it shows that observed phylogenetic differences within the G. roeselii species complex did not reveal differences in thiacloprid tolerance. Second, it confirms that differentiation occurs at the population level, highlighting that susceptibility to toxicants is population-dependent. The population-specific differences were within the range of accepted intraspecific variability from a regulatory standpoint. From an evolutionary-ecological perspective, it remains intriguing to observe how persistent stresses will continue to influence tolerance and whether different populations are on distinct pathways of adaptation. Given that the potential selection process has only lasted a relatively short number of generations, it is crucial to monitor these populations in the future, as even brief exposure periods significantly impact evolutionary responses.

Systematic Characterization of Sesquiterpenes from Dendrobium nobile through Offline Two-Dimensional Chromatography Tandem Mass Spectrometry and Target Isolation.

Dendrobium nobile is a species of the genus Dendrobium that can be used as both a medicinal herb and healthy food. The sesquiterpenes in D. nobile have attracted extensive attention in recent years. In this study, Amide × RP offline two-dimensional chromatography separation tandem high-resolution mass spectrometry combined with GNPS (Global Natural Product Social Molecular Networking) was developed for the characterization of sesquiterpenes in D. nobile. After first-dimensional amide separation, the 70% ethanol extract of D. nobile was divided into 40 fractions, which were analyzed by second-dimensional reverse-phase system separation and LTQ-Orbitrap detection. The raw data was imported into the GNPS, resulting in the efficient clustering of similar substances. Finally, 594 sesquiterpene compounds were characterized, and 25 compounds were isolated based on molecular network analysis, including six new compounds. In vitro bioassays, the isolated compounds decreased NO production in the LPS-induced microglial BV-2 cell model and the content of MDA in PC12 cells, demonstrating neuroprotective activity. These findings unraveled the underlying material and provided valuable insights into the quality control of D. nobile.

Effect of Oscillating Magnetic Fields (OMFs) and Pulsed Electric Fields (PEFs) on Supercooling Preservation of Atlantic Salmon (Salmo salar L.) Fillets.

Salmon, rich in protein and omega-3 fatty acids, has a short shelf life of 1 to 3 days when stored at 2 to 8 °C. Freezing, used for long-term preservation, often results in ice crystal formation. Ice crystals can cause structural damage, leading to cell wall rupture, which can affect the texture and cause nutrient loss. Ultimately, this process reduces the overall quality of the salmon. Supercooling, which cools food below its freezing temperature without forming ice crystals, offers an alternative. This study investigated the effects of oscillating magnetic fields (OMFs) and pulsed electric fields (PEFs) on ice crystal formation during salmon supercooling. The results showed that using OMFs and PEFs in supercooling reduced the storage temperature of salmon, maintaining a similar thiobarbituric acid reactive substances (TBARS) value to that of frozen and refrigerated samples. There was no significant difference in meat color between the fresh and frozen samples, and drip loss weight was comparable between the fresh and supercooled samples. The microbiological counts were the lowest in the supercooled samples compared to the frozen and refrigerated ones. These findings suggest that supercooling storage with OMFs and PEFs can mitigate quality degradation in salmon typically associated with freezing.

Innovative Wearable Sweat Sensor Array for Real-Time Volatile Organic Compound Detection in Noninvasive Diabetes Monitoring.

Wearable sweat sensors are reshaping healthcare monitoring, providing real-time data on hydration and electrolyte levels with user-friendly, noninvasive devices. This paper introduces a highly portable two-channel microfluidic device for simultaneous sweat sampling and the real-time detection of volatile organic compound (VOC) biomarkers. This innovative wearable microfluidic system is tailored for monitoring diabetes through the continuous and noninvasive tracking of acetone and ammonia VOCs, and it seamlessly integrates with smartphones for easy data management. The core of this system lies in the utilization of carbon polymer dots (CPDs) and carbon dots (CDs) derived from monomers such as catechol, resorcinol, o-phenylenediamine, urea, and citric acid. These dots are seamlessly integrated into hydrogels made from gelatin and poly(vinyl alcohol), resulting in an advanced solid-state fluorometric sensor coating on a cellulose paper substrate. These sensors exhibit exceptional performance, offering linear detection ranges of 0.05-0.15 ppm for acetone and 0.25-0.37 ppm for ammonia, with notably low detection limits of 0.01 and 0.08 ppm, respectively. Rigorous optimization of operational parameters, encompassing the temperature, sample volume, and assay time, has been undertaken to maximize device performance. Furthermore, these sensors demonstrate impressive selectivity, effectively discerning between biologically similar substances and other potential compounds commonly present in sweat. As this field matures, the prospect of cost-effective, continuous, personalized health monitoring through wearable VOC sensors holds significant potential for overcoming barriers to comprehensive medical care in underserved regions. This highlights the transformative capacity of wearable VOC sweat sensing in ensuring equitable access to advanced healthcare diagnostics, particularly in remote or geographically isolated areas.

Effects of Gamma-Synthesized Chitosan on Morphological, Thermal, Mechanical, and Heavy-Metal Removal Properties in Natural Rubber Foam as Sustainable and Eco-Friendly Heavy Metal Sorbents

The properties of natural rubber foam (NRF) containing gamma-synthesized chitosan (CS) powder were investigated to address the growing demand for efficient methods to treat industrial wastewater contaminated with heavy metals. The CS powder was prepared by irradiating chitin (CT) powder with varying doses of gamma rays (0–100 kGy), followed by deacetylation using 40% sodium hydroxide (NaOH) at 100 °C for 1 h. The resulting CS powders were then mixed with natural rubber latex (NRL) at different contents (0, 3, 6, and 9 parts per hundred parts of rubber by weight; phr) and processed using Dunlop techniques to prepare the foam samples. The experimental findings indicated that the degree of deacetylation (%DD) of the CS powder increased initially with gamma doses up to 60 kGy but then decreased at 80 and 100 kGy. In addition, when the CS powder was incorporated into the NRF samples, there were increases in total surface area, density, compression set, and hardness (shore OO), with increasing gamma doses and CS contents. Furthermore, the determination of heavy metal adsorption properties for Cu, Pb, Zn, and Cd showed that the developed NRF sample exhibited high adsorption capacities. For instance, their removal efficiencies reached 94.9%, 82.5%, 91.4%, and 97.0%, respectively, in NRF containing 9 phr of 60 kGy CS. Notably, all adsorption measurements were determined using 3 cm × 3 cm × 2.5 cm specimens submerged in respective metal solutions, with an initial concentration of 25 mg/L. However, the removal capacity per unit mass of the sample (mg/g) showed less dependencies on CS contents, probably due to the higher density of CS/NRF composites in comparison to pristine NRF, resulting in a smaller volume of the former being submerged in the solution, subsequently suppressing the effects from CS in the adsorption. Lastly, tests on the reusability of the developed NRF indicated that the samples could be reused for up to three cycles, with the Cu removal capacity remaining relatively high (83%) in the sample containing 9 phr of 60 kGy CS. The overall outcomes implied that the developed NRF with the addition of gamma-synthesized CS not only offered effective and eco-friendly heavy metal adsorption capacity to improve public health safety and the environment from industrial wastewater but also promoted greener and safer procedures for the synthesis/modification of similar substances through radiation technologies.

Recent Advances in Astaxanthin as an Antioxidant in Food Applications.

In recent years, astaxanthin as a natural substance has received widespread attention for its potential to replace traditional synthetic antioxidants and because its antioxidant activity exceeds that of similar substances. Based on this, this review introduces the specific forms of astaxanthin currently used as an antioxidant in foods, both in its naturally occurring forms and in artificially added forms involving technologies such as emulsion, microcapsule, film, nano liposome and nano particle, aiming to improve its stability, dispersion and bioavailability in complex food systems. In addition, research progress on the application of astaxanthin in various food products, such as whole grains, seafood and poultry products, is summarized. In view of the characteristics of astaxanthin, such as insolubility in water and sensitivity to light, heat, oxygen and humidity, the main research trends of astaxanthin-loaded systems with high encapsulation efficiency, good stability, good taste masking effect and cost-effectiveness are also pointed out. Finally, the possible sensory effects of adding astaxanthin to food aresummarized, providing theoretical support for the development of astaxanthin-related food.

Novel aminoquinazolinone-based colorimetric chemosensor for highly selective recognition of gamma-hydroxybutyric acid (GHB) in spiked beverages

Gamma-hydroxybutyric acid (GHB) is one of the substances frequently used in sexual assault that has raised significant concerns in society. Its unique biological properties and the difficulty in detecting it when added to beverages are the main reasons for its misuse. In this work, we designed aminoquinazolinone derivatives with a nitro group as the key structural component, providing exceptional specificity for GHB. These compounds successfully overcome challenges related to interference from structurally similar substances and from compounds commonly found in beverages, with a specific detection mechanism for both the hydroxyl and carboxylate groups present in the GHB structure. The compounds enable facile and rapid measurement without the need for pretreatment steps prior to the GHB measurement, with the result observed by naked eye. The chemosensor probe for GHB detection developed demonstrates the potential of a solution and paper-based analysis formats.

Biodegradation of bisphenol-A in water using a novel strain of Xenophilus sp. embedded onto biochar: Elucidating the influencing factors and degradation pathway

Bisphenol-A (BPA) is an emerging hazardous contaminant, which is ubiquitous in the environment and can cause endocrine disruptor and cancer risks. Therefore, biodegradation of BPA is an essential issue to mitigate the associated human health. In this work, a bacterial strain enables of degrading BPA, named BPA-LRH8 (identified as Xenophilus sp.), was newly isolated from activated sludge and embedded onto walnut shell biochar (WSBC) to form a bio-composite (BCM) for biodegradation of BPA in water. The Langmuir maximum adsorption capacity of BPA by WSBC was 21.7 mg g−1. The free bacteria of BPA-LRH8 showed high BPA degradation rate (∼100 %) at pH 5–11, while it was lower (＜20 %) at pH 3. The BCM eliminated all BPA (∼100 %) at pH 3–11 and 25–45 °C when the BPA level was ≤ 25 mg L−1. The spectrometry investigations suggested two possible degradation routes of BPA by Xenophilus sp. In one route, BPA (C15H16O3) was oxidized to C15H16O3, and then broken into C9H12O3 through chain scission. In another route, BPA was likely hydroxylated, oxidized, and cleaved into C9H10O4P4, which was further metabolized into CO2 and H2O in the TCA cycle. This study concluded that the novel isolated bacteria (BPA-LRH8) embedded onto WSBC is a promising and new method for the effective removal of BPA and similar hazardous substances from contaminated water under high concentrations and wide range of pH and temperature.

Development of cross-linked glucose oxidase integrated Cu-nanoflower electrode for reusable and stable glucose sensing

The demand for glucose-sensing devices has increased along with the increasing diabetic population. Here, we aimed to construct a system with a glucose oxidase (GOx)-integrated Cu-nanoflower (Cu-NF) as the underlying electrode. This novel system was successfully developed by creating a cross-linked GOx within a Cu-NF matrix, forming a c-GOx@Cu-NF-coated film on a carbon screen-printed electrode (CSPE). A comparison of the stabilities of the cross-linking methods demonstrated enhanced durability, with an activity level of >88 % maintained after approximately 35 days of storage in room temperature buffer. Regarding the ability of the c-GOx@Cu-NF modified CSPE to detect glucose via electrochemical methods, the redox potential gap (ΔE) and peak current increased in the presence of GOx. In comparison to that of glucose, the sensitivity of c-GOx@Cu-NF was approximately 8 times greater than that of GOx@Cu-NF, with a detection limit of 0.649 μM and a linear range of 5–500 μM. It sustained an average relative activity of 80 % over 20 days. After 10 cycles of repeated use, the activity remained above 75 %. In terms of evaluating the electrode's specificity for glucose, the detection rate for individual similar substances was approximately 1 %. The introduction of a crosslinking strategy to Cu-NF, leading to enhanced mechanical stability and conductivity, improved the detection capability. Furthermore, this approach led to increased long-term storage stability and reusability, allowing for specific glucose detection. To our knowledge, this report represents the first demonstration of a c-GOx@Cu-NF system for integrating electrochemical biosensing devices into digital healthcare pathways, offering enhanced sensing accuracy and mechanical stability.

Isolation and characterization of synthesis intermediates and side products in hexahydrocannabiphorol

AbstractAfter the Swiss ban of hexahydrocannabinol (HHC) in March 2023, other semisynthetic dibenzopyran cannabinoids emerged on the Swiss gray market. Hexahydrocannabiphorol (HHCP) was the most prominent of them due to its potent cannabimimetic effects, as anecdotal reports from recreational users suggest. In October 2023, a class wide ban of dibenzopyran cannabinoids was introduced in Switzerland to prevent new similar substances from entering the drug market. Various vendors in online shops claim that HHCP is made from CBD, even though they possess different alkyl chain lengths. An HHCP sample was analyzed by gas chromatography coupled to mass spectrometry (GC‐MS), showing that a mixture of molecules with the same or a similar molecular mass as HHCP was present. Six different substances could be isolated from this sample using column chromatography. Four phenols ((9R)‐HHCP, iso‐HHCP, cis‐HHCP, and abn‐HHCP) and two ketones (possible intermediates to (9R)‐HHCP and abn‐HHCP) were identified by various nuclear magnetic resonance spectroscopy (NMR) techniques. (9S)‐HHCP was obtained in an impure fraction. In addition, a fraction was obtained that showed characteristic molecular and fragment ions consistent with bisalkylated products from the synthesis of similar compounds. The presence of abnormal cannabinoids (abn‐HHCP) and bisalkylated cannabinoids is a confirmation that this sample was produced purely synthetically as initially suspected, as these compounds have not been reported in Cannabis. Chiral derivatization of the phenols with Mosher acid chlorides showed that only iso‐HHCP was present as a scalemic mixture, indicating a good stereocontrol of this synthetic procedure.

Tailoring surface terminals on MXene enables high-efficiency electromagnetic absorption

MXene (Ti3C2Tx) is an important category of two-dimensional (2D) materials due to its distinctive metallic conductivity and adjustable surface chemistry. The exceptional benefits of heterointerface and defects or viods, combined with the distinct electromagnetic (EM) properties, inject boundless potential into the advancement of MXene-based absorbers for EM absorbing materials. However, conventional synthetic methods depend on chemical etching of MAX powders (Ti3AlC2) using hazardous HF or similar substances, resulting in MXene sheets with fluorine termination and limited stability in colloidal dispersions under ambient conditions. Herein, varied synthetic routes were proposed to prepare MXenes with different terminal groups by the fluoride-based salts, fluoride-free molten salts, and alkali etching. 2D MXene nanosheets with abundant surface groups are excellent EM absorbing materials, and the MXene etched by the Lewis acid CuCl2 delivered remarkable reflection loss (RL) value of −47.56 dB at 2.5 mm and broad bandwidth of 4.8 GHz due to promoted interfacial polarization. By conducting a thorough examination of the structural changes in MXenes, this study aims to propose a viable method for delaminating single-layer MXene and elucidate the EM absorption mechanisms.

Solubility of 5-chloro-2-nitroaniline in twelve mono-solvents: Characterization, determination, analysis, and model correlation

The solubility of 5-chloro-2-nitroaniline in twelve mono-solvents (water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, acetone, 2-butanone, acetonitrile, methyl acetate, ethyl acetate) at 101.2 kPa (T = 283.15 ∼ 323.15 K) was investigated by experimental determination and molecular simulation. The static gravimetric tests showed that the solubility of 5-chloro-2-nitroaniline increased with the increase of absolute temperature, in the following order: 2-butanone > acetone > methyl acetate > ethyl acetate > acetonitrile > n-butanol > n-propanol > ethanol > isopropanol > isobutanol > methanol > water. The modified Apelblat, Wilson, NRTL, UNIQUAC and Margules models were used to correlate the experimental data, and the fitting results of the five models were satisfactory. By comparing the average ARD and RMSD values of the five models, the correlation results of the modified Apelblat model were the best. Hirshfrld surface analysis (HS) and molecular electrostatic potential surface (MEPS) were used to determine the internal interaction of 5-chloro-2-nitroaniline solution. The Hansen solubility parameters (HSPs) was utilized to assess the solvents’ capability and to elucidate its ability to dissolve 5-chloro-2-nitroaniline. Furthermore, mixing thermodynamic characteristics of 5-chloro-2-nitroaniline in selected solvents were calculated by the NRTL model, which revealed that the mixing process was spontaneous and entropy-driven. These experimental results could be utilized for the purification, crystallization, and industrial applications of 5-chloro-2-nitroaniline as well as similar substances.

Solubility of N-Acetyl-L-glutamine in twelve Mono-solvents: Characterization, Determination, Analysis, and model correlation

In this work, the solid–liquid equilibrium solubility and solvent effects of N-acetyl-L-glutamine in twelve mono-solvent systems (water, methanol, ethanol, n-propanol, n-butanol, isobutanol, sec-butanol, acetonitrile, acetone, ethyl acetate, 2-butanone, methyl acetate) were reported at the pressure of 101.2 kPa (at T = 283.15–––323.15 K). Among the twelve mono-solvents, the solubility increased with the increase of absolute temperature, the order is: water > methanol > ethanol > sec-butanol > n-propanol > 2-butanone > isobutanol > acetone > methyl acetate > ethyl acetate > n-butanol > acetonitrile. The modified Apelblat model, Wilson model, NRTL model and UNIQUAC model were employed to correlate the experimental solubility, and the fitting results of the four models were all satisfactory. In addition, through comparison of the average ARD and RMSD values of the four models, the modified Apelblat model achieved the best correlation result. Hirshfeld surface analysis (HS) and molecular electrostatic potential surface (MEPS) were used to determine the internal interactions within N-acetyl-L-glutamine solutions. The Hansen solubility parameters (HSPs) and the coverage Pearson correlation coefficients (PCC) heatmap were utilized to assess the solvents’ capability and to elucidate its ability to dissolve N-acetyl-L-glutamine. Furthermore, mixing thermodynamic characteristics of N-acetyl-L-glutamine in selected solvents were calculated by the NRTL model, which revealed that the mixing process was spontaneous and entropy-driven. These experimental results could be utilized for the purification, crystallization, and industrial applications of N-acetyl-L-glutamine as well as similar substances.

Rhinitis medicomentosa and substance addiction

BackgroundRhinitis medicomentosa (RM) is a form of non-allergic rhinitis caused by the use of nasal decongestants for longer than the recommended duration. Because of this problem of use, addiction to the drug occurs in individuals. In our study, we aimed to evaluate the susceptibility of RM patients to substance addiction.MethodsThe study was planned as a prospective, multicentric study between September 2022 and September 2023. Patients diagnosed with RM were included in the study. Beck depression scale, Drug use disorders identification test, Substance Abuse Proclivity Scale were applied to the patients participating in the study. The research data were analyzed electronically with SPSS program version 25.ResultsThe study included 86 patients with an average age of 31 years. The average duration of medication use was 22 months. Age, gender, duration of nasal congestion, duration of drug use and smoking were not independent predictors for depression and substance use tendency.ConclusionThe relationship between RM and addictive substances is not clear. The tendency to use drugs did not increase in RM patients. In the light of these data, we think that there is no need for a practice other than routine functioning in the use of drugs and similar substances that are likely to cause addiction in RM patients.

Trenched microwave resonator integrated with porous PDMS for detection and classification of VOCs with enhanced performance

Microwave resonators combined with polymer absorption layers are widely used in volatile organic compound (VOC) detection based on their variable resonant frequencies. However, the response time is limited due to the polymer’s slow volumetric absorption of VOC molecules. By constructing a porous structure in Polydimethylsiloxane (PDMS), resulting in reduced the response time to as short as 71.1%. To mitigate the sensitivity decline caused by the porous PDMS, a trenched-substrate complementary split-ring resonator (CSRR) is proposed for enhancing the interaction between the electromagnetic fields (EMFs) and the porous PDMS with VOCs. The removal of the substrate beneath CSRR’s sensing region enhances the effective EMF, increasing frequency and amplitude sensitivities up to 175.5% and 137.8%, respectively. Responses to four common VOCs by the sensor show a maximum sensitivity of 217 Hz/ppm and a minimum limit of detection of 295 ppm. Additionally, resonant parameters and extracted lumped parameters are utilized to establish two decision-tree-based VOC classification models, achieving high accuracies of 98.71% and 99.59%, respectively. And the latter one fully utilizing responses throughout the swept band, proves superior in identifying similar substances. This sensor technology helps promote the sensitive detection and accurate classification of diverse VOCs.

The VERA software: Implementation of the acute fish toxicity endpoint and its application to pharmaceutical compounds

The Virtual Extensive Read-Across software (VERA) is a new tool for read-across using a global similarity score, molecular groups, and structural alerts to find clusters of similar substances; these clusters are then used to identify suitable similar substances and make an assessment for the target substance. A beta version of VERA GUI is free and available at vegahub.eu; the source code of the VERA algorithm is available on GitHub. In the past we described its use to assess carcinogenicity, a classification endpoint. The aim here is to extend the automated read-across approach to assess continuous endpoints as well. We addressed acute fish toxicity. VERA evaluation on the acute fish toxicity endpoint was done on a dataset containing general substances (pesticides, industrial products, biocides, etc.), obtaining an overall R2 of 0.68. We employed the VERA algorithm also on active pharmaceutical ingredients (APIs). We included a portion of the APIs in the training dataset to predict APIs, successfully achieving an overall R2 of 0.63. VERA evaluates the assessment's reliability, and we reached an R2 of 0.78 and Root Mean Square Error (RMSE) of 0.44 for predictions with high reliability.

Effect of the combination of fluoxymesterone and a commercial blend of additives on the sex proportion, growth, and survival of Nile tilapia (Oreochromis niloticus) fry

In the commercial culture of Nile tilapia (Oreochromis niloticus), monosex, all-male populations obtained through steroid sex reversal is the most commercially used method to eliminate unwanted reproduction and increase final productive and economic yield. However, the rapid growth of Nile tilapia culture has led, in some regions, to an increase in infectious diseases and mortality in all stages of commercial culture. To reduce this, without the abuse of antibiotics or similar substances, feed additives are currently used in all stages, including the fry period, during the sex reversal process. The objective of this work was to evaluate the effect of synthetic steroid Fluoxymesterone (FM) at various concentrations in combination with a commercial Blend of additives (BA) on the percentage of males, growth, and survival of Nile tilapia fry. Five treatments (FM20, FM5+BA, FM10+BA, FM20+BA, and BA+FM20) and a control group were evaluated. Treatments differ in the order in which the commercial blend (2 g) was added and the FM concentration (5, 10, and 20 mg). The feeding trial lasted for 30 days using a sexually undifferentiated population of Nile tilapia. The results showed a decrease in the percentage of males in all treatments supplemented with the BA, compared to the FM20 treatment (containing 20 mg without BA). Growth and survival were positively affected by the inclusion of the BA in all treatments, showing higher values than those observed in the control group. Further studies are necessary to determine the FM-BA interaction.