Biomonitoring Research Articles

Water Quality Assessment using Selected Macroinvertebrate Based Indices and Water Quality Index of Sungai Air Hitam Selangor

A study was conducted from July to December 2022 at Sungai Air Hitam, a small tributary of the Selangor River located within the Tanjung Karang Sub-basin in Malaysia (coordinates: 3° 24' 27" N, 101° 25' 54" E to 3° 28' 14" N, 101° 26' 59" E). This confluence is situated near three major downstream water treatment plants. The study assessed six water quality parameters—pH, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia (NH3), and suspended solids (SS)—to calculate the Water Quality Index (WQI). Macroinvertebrates were sampled simultaneously using the dipping net method to obtain biotic indices for further evaluation of water quality. The results indicated that the WQI classified Sungai Air Hitam as Class III, with scores ranging from 56.9 to 64.6, suggesting the river is suitable for water supply and fisheries. However, the Biological Monitoring Working Party (BMWP) index categorized the water quality as poor, with scores between 30 and 42. Similarly, the Average Score Per Taxon (ASPT) ranged from 3.25 to 5.25, indicating pollution or environmental impact, while the Family Biotic Index (FBI) further classified the river as having poor to very poor water quality, with scores between 6.57 and 8.11. Overall, the study suggests that Sungai Air Hitam has experienced some degree of ecological degradation. These findings emphasize the need for continuous monitoring and remediation efforts to preserve and restore water quality.

Optimizing aquatic weed management in Lake Ossa, Cameroon: Harnessing the power of biological control and real-time satellite monitoring

Salvinia, Salvinia molesta Mitchell (Salviniaceae) is a free-floating aquatic fern native to Brazil and considered one of the worst weeds in the world. When left unchecked, salvinia forms dense mats on the water surface, limiting sunlight penetration and altering water quality that disrupt ecosystem processes. In 2016, salvinia was first reported in Lake Ossa, Cameroon, and by summer 2021, had expanded to cover almost 49 % of the lake’s 4,000-hectare surface. A multinational team initiated a biological control and monitoring program, importing the salvinia weevil, Cyrtobagous salviniae Calder & Sands (Coleoptera: Curculionidae) from Louisiana, USA, in summer 2021. The objectives of this study were to: quantify the changes in salvinia cover and other floating vegetation, document the establishment and impact of the biological control program, and deliver a tool for near-real time monitoring of floating vegetation. We developed a satellite-based remote sensing application to document in near real-time the changes in coverage of floating vegetation. Using this tool, we quantified the reduction in the salvinia coverage by 80 % within three years of the release of the weevil. Field surveys in 2022 and 2023, demonstrated weevil establishment in the lake and widespread salvinia browning that was associated with weevil damage. Linear regressions of the percent cover of floating vegetation over time, demonstrated that after the weevil release, the rate of change decreased to −1.7 % per 60 days. Field monitoring and satellite imagery showed the establishment of a sedge (Oxycaryum sp., Cyperaceae) within the salvinia mat in late 2021. This secondary invasion slowed the reduction in coverage of floating vegetation from −1.7 % to −0.6 % per 60 days, and warrants further research. By late 2023, the revitalization of Lake Ossa restored fishing and transportation opportunities for the community, and also the comeback the emblematic African manatee. The success of the biological control of salvinia in Lake Ossa is not surprising due to its tropical conditions. However, it highlights the importance of early intervention and continuous monitoring. We propose that the integration of biological control and remote sensing technology is becoming more accessible and can be automated; therefore, a replicable model for future invasive weed programs around the world.

Modelling and spatial prediction of earthworms ecological-categories distribution reveal their habitat and environmental preferences

Earthworms are one of the important soil animals and have been generally described as soil engineers. Knowledge on environmental conditions driving the distribution and population of this soil animal and the habitat which support these conditions especially at the ecological level is required to understand their responses to these environmental conditions at different habitats so as to guide its usage as bio indicator of soil quality and health. In this study we use RandomForest (RF), a machine learning algorithm to model species distribution, density/abundance based (SDM/SAM) and predict the biodiversity distribution (richness and density, ind.m−2) of three basic earthworms ecological categories: epigeic, endogeic and anecic (including the epi-anecic subcategory) across soil and climate variables at multiple habitat type/land uses in Germany. Our study shows there are spatial/ geographic variation in the distribution of the species richness and density among the three earthworms’ ecological categories. Also their environmental and habitat preferences are equally different, while epigeic species are predicted to be climate driven mostly in forests, endogeics are predicted to be the most diverse (in richness and density), but are mostly driven by soil textural contents (clay and silt) and found primarily in arable and grassland. Vineyard and crop flood plain are predicted to be suitable and the preferred habitat for anecics/epi-anecics. This study also identify optimum environmental gradient at which the species density is at the peak in each of the earthworm’s ecological category which would not only provide guide on soil biodiversity monitoring but also the soil health status.

Evaluation of various mass spectrometry mode based on gas chromatography for quantifying the polycyclic aromatic hydrocarbon metabolites in human urine

Hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) are frequently used as biomarkers to assess human exposure to polycyclic aromatic hydrocarbons (PAHs), which are typically present in minute concentrations in the human body. Although several studies have outlined methods for measuring OH-PAHs in human urine, these approaches may have limitations concerning the range of compounds detected, the sample volume required for pre-treatment, accuracy, and instrument maintenance costs. Advances in mass spectrometry technology have facilitated the use of various mass spectrometry modes based on gas chromatography. It is essential to evaluate different mass spectrometry modes to identify a more reliable and practical method for quantifying OH-PAHs in urine. Our comparative analysis of three gas chromatography-mass spectrometry modes revealed that advanced electron ionization (AEI) mode exhibited greater sensitivity for determination compared to electron ionization (EI) mode in tandem mass spectrometry. The method validation criteria were satisfied by GC-AEI-MS/MS, which demonstrated acceptable measurement errors (MEs) ranging from -23.0 % to 19.5 %, recoveries between 81.6 % and 112.1 %, and precision levels below 10.1 %. Furthermore, the reliability and accuracy of the GC-AEI-MS/MS method were corroborated through Intraclass Correlation Coefficient (ICC) evaluation (values > 0.75), participation in external proficiency testing programs (G-EQUAS), and analysis of certified reference materials, which exhibited a relative deviation of <6.1 %. In summary, GC-AEI-MS/MS is a robust and reliable method for analyzing urine samples and conducting large-scale human biological monitoring. It was employed to determine 16 OH-PAHs in human urine as part of the China National Human Biomonitoring Program (CNHBM).

Evaluation of the effect of disposal of landfill leachate in a sewage treatment plant composed of stabilization ponds

This study aimed to evaluate the combined treatment system of domestic sewage and leachate by serial stabilization ponds in a Wastewater Treatment Plant (WWTP). The WWTP had two parallel pond modules, one receiving (module II—pond M10) and the other not receiving leachate (module I—pond M5). Physical, chemical, and biological monitoring parameters collected from January 2017 to December 2021 were evaluated. High reducing efficiency for ammonium nitrogen was found, with an average of 95.7 ± 2.5%. BOD5 and COD can be considered statistically different for a 95% confidence level in the two pond modules. The phytoplankton community was composed of 46 taxa distributed in four taxonomic classes: 6 belonging to the Cyanobacteria group (13%), 22 to the Green Algae group (48%), 4 to the Diatoms group (9%), and 14 to the Phytoflagellate group (30%). No ecotoxicity was detected for the evaluated pond effluent samples. Thus, although the insertion of leachate impacted the quality of the final effluent of the ponds and the organic matter, it may not have affected the effluents’ ecotoxicity. This research helps to understand the impacts of long-term leachate insertion in a real treatment system using stabilization ponds for combined treatment. In addition to the usual efficiency evaluation parameters, ecotoxicological tests and phytoplankton are also evaluated.

Post-Functionalization of Fluorinated Dibenzosulfone-Based Conjugated Polymer for Smart 'Turn-off' Sensing of Cu2+ Ions.

Post-functionalization of conjugated polymeric backbone with various N-containing heterocycles through nucleophilic aromatic substitution reaction (SNAr) demonstrates crucial tailoring of their photophysical properties. This study explores an approach of post-polymerization modification of a fluorinated dibenzosulfone-based conjugated polymer aiming to incorporate functional groups having coordinating sites to bind metal ions. The resulting polymers, namely BDT-DBTS-IM, BDT-DBTS-TR, and BDT-DBTS-PY revealed successful substitution reactions with imidazole, triazole, and pyridine respectively, and showed significant changes in their absorption and emission properties. Notably, BDT-DBTS-IM demonstrated exceptional performance as a chemosensor, exhibiting a dramatic fluorescence turn-off response specifically to copper ions (Cu2+) with the limit of detection of 26 nM and Stern-Volmer quenching constant (KSV) of 8.2×105 Lmol-1. This high selectivity and sensitivity are attributed to the ability of the imidazole group to form a stable complex with Cu2+, resulting in both static and dynamic quenching efficiently. Our findings underscore the potential of post-polymerization modifications to significantly enhance the functionality of conjugated polymers. The ability of BDT-DBTS-IM to detect trace levels of copper ions with high precision highlights its practical utility in environmental and biological monitoring. This research not only demonstrates an approach for post-polymeric modification through SNAr reaction but also opens new avenues for developing sensors.

Comprehensive Assessment of Carbon Disulfide Exposure in Laboratories—Air and Biological Monitoring Approaches

Carbon disulfide (CS2) is a highly toxic and flammable solvent extensively used in chemical processes and laboratory analyses. This review examines both air and biological monitoring methods for assessing the exposure of laboratory workers to CS2. Emphasis is placed on the measurement of airborne CS2 concentrations and the monitoring of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine, a key biomarker of exposure. By analysing case studies and practical applications, the paper outlines the effectiveness and limitations of current monitoring techniques. Additionally, the review addresses key challenges such as CS2 volatility, dietary influence on biomarker levels, and the sufficiency of protective measures, including nitrile gloves. It also proposes best practices to mitigate exposure, such as improved ventilation, the use of polyvinyl alcohol gloves, and the substitution of CS2 with less hazardous solvents. This comprehensive review underscores the need for continuous vigilance in managing chemical exposure and offers insights into how laboratories can better protect their workers by integrating air and biological monitoring strategies.

Correlation between serum and saliva sex hormones in young female athletes.

Saliva sampling provides a practical noninvasive way for biological monitoring of steroid hormones but few studies have focused on saliva sex hormones in female athletes, and it is still unknown whether salivary concentrations are an accurate reflection of blood concentrations in this population. The aim of this study was therefore to evaluate the correlation between serum and saliva estradiol (E2) and progesterone (PG) in 10 young female athletes with normal menstrual cycle. Thirty blood and saliva samples were taken at rest in a fasting state in order to analyze E2 and PG concentrations, during 3 different hormonal periods: Status 1: low E2 and low PG (end luteal/early follicular); Status 2: high E2 and low PG (end follicular/peri-ovulatory); Status 3: high PG (mid-luteal). A strong correlation was found between serum and saliva PG (r=0.914, P<0.01), whereas a weaker but still significant relationship was observed between serum and saliva E2 (r=0.755, P<0.01). The most significant correlations obtained for E2 were during Status 2 (r=0.941, P<0.01) and during Status 3 for PG (r=0.817, P<0.01). Although it remains challenging to produce precise identification with only saliva samples for each menstrual cycle phase, results seem to show that saliva can provide a convenient substitute to serum for sex hormones in female athletes during longitudinal monitoring. This is of particular interest in this population, with the number of female athletes suffering from an altered menstrual cycle, sometimes even during regular menstruation.

Unveiling mercury exposure sources in e-waste recycling with biomonitoring - A Portuguese case study

Abstract Background Mercury (Hg), a global pollutant, poses risks to both human and environmental health. The management and recycling of electrical and electronic waste (e-waste) is recognized as having the potential to promote workers’ exposure to this pollutant. Human biomonitoring (HBM) is a tool that can be used to evaluate exposure and monitor the health of workers. The objective of this study was to characterize exposure of workers from an e-waste recycling company and to analyze the relevance that HBM holds in the detailed characterization of exposure. Methods A cross-sectional observational study was conducted using data collected within the framework of the European Human Biomonitoring Initiative (HBM4EU). Data from environmental monitoring (settled dust) and biological monitoring (urine and hair) of 30 workers potentially exposed to Hg were analyzed in comparison with 12 unexposed workers from other occupational settings (controls). Results Exposed workers did not exhibit significantly higher concentrations of Hg in urine when compared to control workers. We found a significantly positive correlation between the concentration of Hg in urine (ρ = 0.688; p ≤ 0.001) and hair (ρ = 0.470; p ≤ 0.01) and the consumption of fish and shellfish. Conclusions Diet appears to be the most significant source of Hg in this context. These results suggest the importance of information and dietary habits to prevent mercury exposure. HBM stands out as an essential tool for identifying the most relevant exposure sources and risk management measures for workers and the general population. Key messages • Diet appears to be the most significant Hg source in workers from a Portuguese e-waste company. • HBM stands out as essential for identifying the most relevant exposure sources and risk management.

Utilizing Insects as Bioindicators: An Approximation for Conservation in Urban Lentic Ecosystems in Central Chile.

This study considered using insect families as bioindicators to establish the health status of an ecosystem of lentic bodies. The water quality in urban lentic bodies in the Metropolitan Region, Chile, was evaluated from aquatic insect family assemblages and physicochemical variables for conserving aquatic life. Evaluations were carried out in parallel at four sampling stations of three water bodies (Batuco Wetland, Carén Lagoon, and Chada Reservoir) in a 2-3-year series, spring (2015, 2017, and 2018) and fall (2016 and 2018), with three replicates. Families were randomly sampled and aquatic insects were identified; abundance and richness differences were compared with non-parametric tests. Physicochemical variables were measured using portable multiparametric and laboratory chemical analyses to determine the water quality. A Canonical Correspondence Analysis was applied for insect families and the physical-chemical variable. In order to categorize the health of these water bodies based on aquatic insect composition and abundance, the Family Biotic Index (FBI), British Biological Monitoring Work Party (BMWP), and Stream Invertebrate Grade Number-Average Level (SIGNAL), adapted for Chile by Figueroa et al. (2007), were calculated. The eudominant insect families were Corixidae and Chironomidae in Batuco, Chironomidae and Corixidae in Carén, and Corixidae in Chada. Baetidae was dominant in Carén and Chada. The water bodies were classified in descending order of water quality by Chilean physicochemical standards: Chada > Carén > Batuco. The TSS (total suspended solids), phosphorus, and electrical conductivity were strongly positively correlated and negatively associated with dissolved oxygen. The TSS level was the most significant influential factor. The BMWP value and the SIGNAL differed from the FBI, but the first was more restrictive, contributing to the conservation of these ecosystems. Based on the nitrogen and phosphorus levels in the water bodies, all of them were eutrophic. Given the ecosystem diversity and complexity, studies should delve deeper into wetlands to establish methods that contribute to determining water quality, using insect families as bioindicators and physicochemical variables.

Causal associations between the insulin-like growth factor family and sarcopenia: a bidirectional Mendelian randomization study.

Insulin-like growth factor (IGF) is closely associated with sarcopenia, yet the causal relationship of this association remains unclear. This study aims to explore the potential causal relationship between members of the IGF family and sarcopenia from a genetic perspective through bidirectional Mendelian randomization (MR) analysis using two-sample datasets. Five genetically predicted factors of the IGF family (IGF-1, IGF-1R, IGF-2R, IGFBP-3, IGFBP-7) as one sample, while four relevant features of sarcopenia (low hand grip strength, appendicular lean mass, whole body fat-free mass, and walking pace) as another sample, in conducting a two-sample MR analysis. The forward MR results of the relationship between IGF and sarcopenia showed that elevated levels of IGF-1 reduced the risk of low hand grip strength (OR = 0.936, 95% CI=0.892-0.983, P = 0.008) and increased appendicular lean mass of the extremities and whole body fat-free mass (OR = 1.125, 95% CI=1.070-1.182,P = 0.000; OR =1.076, 95% CI=1.047-1.106, P=0.000), reduced the risk of sarcopenia. Elevated IGF-1R also favored an increase in whole body fat-free mass (OR=1.023, 95% CI=1.008-1.038, P =0.002), and the appendicular lean mass trait was more pronounced with elevated IGFBP-3 and IGFBP-7 (OR=1.034, 95% CI=1.024-1.044, P =0.000; OR=1.020, 95% CI=1.010-1.030, P=0.000). Inverse MR results of the effect of sarcopenia on IGF showed that decreased hand grip strength may elevate IGF-1 levels (OR=1.243, 95% CI=1.026-1.505,P =0.027), whereas improvements in appendicular lean mass, whole body fat-free mass traits, and increased walking pace decreased IGF-1 levels (OR=0.902, 95% CI: 0.877-0.927, P = 0.000; OR=0.903, 95% CI=0.859-0.949,P = 0.000; OR=0.209, 95% CI=0.051-0.862,P = 0.045). Also decreased hand grip strength may elevate IGF-1R levels (OR=1.454, 95% CI=1.108-1.909, P =0.007), and appendicular lean mass stimulated high expression of IGFBP-1 (OR=1.314, 95% CI=1.003-1.722, P =0.047). Heterogeneity and pleiotropy were not detected in all results, and the results were stable and reliable. There is a bi-directional causal association between IGF family members and the risk of sarcopenia, which provides a more adequate basis for early biological monitoring of sarcopenia and may provide new targets for early intervention and treatment of sarcopenia.

Validation of physicochemical water quality results through cross-checking with biological indices

ABSTRACT Biological assessment of rivers is critical for evaluating ecosystem health, detecting ecological changes, validating physicochemical monitoring data, assessing the effectiveness of water treatment systems, conserving biodiversity, and guiding water resource management. In this study, the surface water quality of the Karkheh River basin was evaluated using the National Sanitation Foundation Water Quality Index (NSFWQI) and the Iranian Surface Water Quality Index (IRWQIsc) for qualitative analysis. For biological monitoring, the Biological Monitoring Working Party (BMWP) index, along with the Average Score per Taxon (ASPT) and the Hilsenhoff Biotic Index (HFBI), was employed to provide a comprehensive assessment. Water quality was analyzed across 18 sampling stations, revealing significant spatial variation. Upstream areas exhibited relatively good conditions, with NSFWQI and IRWQIsc values of 59 and 68, respectively. In contrast, downstream locations near urban and agricultural areas demonstrated poor water quality, with values of 27 and 33, respectively. Overall, approximately 70% of the river's length has been severely impacted, highlighting the need for targeted planning and management to mitigate pollution. The biological indices corroborated the physicochemical results, revealing severe ecological stress in polluted regions. The close alignment between the NSFWQI and biological indicators emphasizes the importance of a multifaceted approach in assessing aquatic health. Key factors contributing to the river's degradation include excessive water extraction, untreated wastewater discharge, and diminished self-purification capacity, particularly in downstream areas.

A smartphone-assisted chromogenic and fluorogenic dual-channel sensor for specific determination of toxic Pb2+ ions with multifaceted applications

Heavy metal pollutants, such as Pb2+ ions, pose a substantial hazard to human health and ecosystems, and it was of great significance to develop cost-effective and portable techniques for online and visual detection of Pb2+. Herein, we fabricated a novel chromogenic and fluorogenic dual-channel sensor NQA through a Schiff base reaction involving a dicyanoisophorone derivative and isoniazid, enabling effective detection of Pb2+ ions. Upon complexation with Pb2+ ions at a 1:1 M ratio, the fluorescence intensity of NQA exhibited a remarkable enhancement. The naked-eye colorimetric detection utilizing NQA demonstrated a distinct color change to specific Pb2+ ions concentration from yellow to light pink. Based on this principle, a smartphone-assisted sensing platform was developed for visual and high-quality identification of Pb2+ in real samples. The UV binding constant for Pb2+ ions was determined to be 1.84 × 105 M−1, with a detection limit of 0.38 μM. Furthermore, the versatility of NQA extended to applications in naked-eye test paper experiments, the detection of Pb2+ ions in real water samples and living cells, showcasing its potential for environmental and biological monitoring.

Gestational Trophoblastic Tumours: Experience of the Oncology Department of the Moulay Ismail Military Hospital in Meknes (10 Cases)

Gestational trophoblastic tumors (GTTs) are the malignant forms of gestational trophoblastic diseases. They always follow a pregnancy, most often molar. The diagnosis of GTT is based on an abnormal course of HCG (chorionic gonadotropin hormone) and/or signs of ultrasound invasion and/or histological confirmation. We report a retrospective series of 10 cases of GTT collected at the Medical Oncology Department of the Moulay Ismail Military Hospital in Meknes over an 8-year period from January 2012 to January 2020. The analysis of our series led to the conclusion that: The average age of onsetis 42 years. 90% of our patients were pauciparic. The causal pregnancy was in 90% of the cases a molar pregnancy. The extension assessment was mainly based on the TAP CT identifying the lung as the main metastatic site in 40% of cases. 5 patients (50% of cases) underwent hysterectomy with post operative chemotherapy. 60% of our patients were classified as low risk according to the FIGO score and received methotrexate mono-chemotherapy. 4 patients were classified as high-risk and were treated with poly chemotherapy, the main protocol of which was EMA-CO. All our patients benefited from clinical and biological monitoring, before each chemotherapy session; then weekly and monthly after negativation, up to 12 months in case of good prognosis GTT, and up to 18 months in case of bad prognosis GTT. One case of MTX relapse (the case of IPTT) was reported and for which a 2nd line CMT with a favourable evolution was indicated. This study allowed us to analyze the cure rate, which was 100% for patients who were treated and had completed their monitoring.

Genetic lineages of &lt;i&gt;Parisotoma notabilis&lt;/i&gt; sensu lato (Hexapoda, Collembola) and their use in biological monitoring

Widespread species of small soil arthropods are being traditionally used in the biological monitoring of the environment. A promising development in this direction could be the usage of genetic methods, namely the composition of genetic lineages in populations of polytypic species. These species include the widespread springtail, Parisotoma notabilis sensu lato, which is especially abundant in Europe. At present, six lineages of this complex are known, the genetic distances between which are sufficiently close to the species. Previously, we showed the differentiation of genetic lineages in an urbanization gradient (natural forest – forest park – urban lawn) using the Moscow region as an example. In this work, the divergence of genetic lineages in these habitats was confirmed for various natural zones. The least disturbed habitats are marked by lineages L2, L4-Hebert and L0, the most disturbed ones by L1. Monitoring changes in the soil layer of ecosystems is possible only in zones of sympatry of different P. notabilis genetic lineages, i.e. the areas where they co-occur. Such areas seem to include the entire European part of Russia.

Biofeedback-Based Closed-Loop Phytoactuation in Vertical Farming and Controlled-Environment Agriculture.

This work focuses on biohybrid systems-plants with biosensors and actuating mechanisms that enhance the ability of biological organisms to control environmental parameters, to optimize growth conditions or to cope with stress factors. Biofeedback-based phytoactuation represents the next step of development in hydroponics, vertical farming and controlled-environment agriculture. The sensing part of the discussed approach uses (electro)physiological sensors. The hydrodynamics of fluid transport systems, estimated electrochemically, is compared with sap flow data provided by heat-based methods. In vivo impedance spectroscopy enables the discrimination of water, nutrient and photosynthates in the plant stem. Additionally to plant physiology, the system measures several air/soil and environmental parameters. The actuating part includes a multi-channel power module to control phytolight, irrigation, fertilization and air/water preparation. We demonstrate several tested in situ applications of a closed-loop control based on real-time biofeedback. In vertical farming, this is used to optimize energy and water consumption, reduce growth time and detect stress. Biofeedback was able to reduce the microgreen production cycle from 7 days to 4-5 days and the production of wheatgrass from 10 days to 7-8 days, and, in combination with biofeedback-based irrigation, a 30% increase in pea biomass was achieved. Its energy optimization can reach 25-30%. In environmental monitoring, the system performs the biological monitoring of environmental pollution (a low concentration of O3) with tomato and tobacco plants. In AI research, a complex exploration of biological organisms, and in particular the adaptation mechanisms of circadian clocks to changing environments, has been shown. This paper introduces a phytosensor system, describes its electrochemical measurements and discusses its tested applications.

A broadband tunable THz sensor based on graphene metasurface

In this paper, we design a polarization-independent and angle-insensitive wideband THz graphene metamaterial sensor. The proposed metasurface sensor consists of six layers, which are silicon dioxide substrate, metal reflector, air layer, graphene metasurface with microstructure, ion-gel layer and silicon dioxide dielectric layer from bottom to top. The sensor was simulated by using CST Microwave Studio software, and the absorption and sensing performance were analyzed. The results show that the absorption rate is more than 95 % in the range of 1.05–4.07 THz. In addition, when the Fermi energy level of graphene is changed, the absorption rate can be adjusted from 20 % to more than 95 %. At the same time, the absorptivity of the device can be maintained above 80 % before 60° when the TE and TM waves are incident, and it is insensitive to the polarization angle due to the central symmetry of the graphene surface microstructure. By changing the thickness of the air layer, the device can achieve maximum absorption at h2=30μm, where the maximum frequency shift sensitivity is 2.179 THz/RIU. The influence of structure parameters and incident angle on the absorption spectrum shows that the proposed structure has good stability. The proposed metasurface sensor has potential application prospects in biological detection and medical monitoring, broadening the application range of THz functional devices.

Preparation and Application of Two-Dimensional Ta4C3 MXene/Gold Nanostar Composite SERS Substrates for Thiram Detection.

Surface-enhanced Raman scattering (SERS) is a novel spectroscopic technique that enables the identification of analytes through analysis of their unique chemical signatures. Its high sensitivity, specificity, and rapid response make it a valuable tool in a range of fields, including biological detection, food safety, and environmental monitoring. However, traditional SERS nanoparticle substrates are susceptible to instability and agglomeration. In this study, Ta4C3 MXene/gold nanostar (AuNSs) hybrids were prepared as SERS substrates. By optimizing the experimental conditions of AuNSs, the optimal preparation method for the Ta4C3 MXene/AuNSs composite structure was identified. The addition of MXene to the Ta4C3 MXene/AuNSs hybrid substrates was found to enhance the sensitivity of the composite for Raman detection, as evaluated using 4-aminothiophenol (PATP) as a Raman molecule. This improvement in sensitivity is attributed to the enhanced electromagnetic properties of the hybrid substrates, which facilitate more efficient charge transfer and enhance the Raman scattering process. The limit of detection (LOD) of Ta4C3 MXene/AuNSs is 10-9 M for PATP and 10-7 M for thiram solutions. In addition, good reproducibility and spatial uniformity were obtained for the Raman signals of Ta4C3 MXene/AuNSs. Furthermore, Ta4C3 MXene/AuNSs were combined with filter paper to create paper-based SERS substrates that could be used for detection. By directly wiping the apple peel and subsequently detecting the thiram residues using Ta4C3 MXene/AuNSs, the level of detection of thiram residues on the peel surface was down to 7.8 ng/cm2.

Dynamic Tracking of Biological Processes Using Near-Infrared Fluorescent Single-Walled Carbon Nanotubes.

Biological processes are characterized by dynamic and elaborate temporal patterns driven by the interplay of genes, proteins, and cellular components that are crucial for adaptation to changing environments. This complexity spans from molecular to organismal scales, necessitating their real-time monitoring and tracking to unravel the active processes that fuel living systems and enable early disease detection, personalized medicine, and drug development. Single-walled carbon nanotubes (SWCNTs), with their unique physicochemical and optical properties, have emerged as promising tools for real-time tracking of such processes. This perspective highlights the key properties of SWCNTs that make them ideal for such monitoring. Subsequently, it surveys studies utilizing SWCNTs to track dynamic biological phenomena across hierarchical levels─from molecules to cells, tissues, organs, and whole organisms─acknowledging their pivotal role in advancing this field. Finally, the review outlines challenges and future directions, aiming to expand the frontier of real-time biological monitoring using SWCNTs, contributing to deeper insights and novel applications in biomedicine.

Assessment of the Workers' Exposure to Styrene in a Polymer Manufacturing Industry: Correlation Between Air and Biological Monitoring Methods

Background and Objective: Styrene is widely used in the production of many products, such as paints, glues, and plastics. There is a high potential for exposure to this toxic solvent in workplaces. The present study aimed to assess the levels of exposure to styrene via air and biological monitoring methods and determine the correlation between them in styrene-exposed workers. Materials and Methods: A total of 44 workers from a polymer manufacturing industry were studied, and the workers’ inhalational exposure to styrene was measured. In addition, the levels of urinary mandelic acid were determined. Data was analyzed using the SPSS (version 22.0) software. Results: The time-weighted average (TWA) exposure to styrene was equal to 18.35±11.02 ppm. The mean urinary mandelic acid was 150 mg/g creatinine. Moreover, a significant correlation was observed between the styrene concentration and the urinary mandelic acid (r=0.841). The correlation was stronger in workers with no skin exposure than in those with this type of exposure. Furthermore, a significant correlation was observed based on working hours per day (less than or more than 8 hours per day) so that the correlation was better for workers with shorter exposures (r= 0.922 vs. 0.713). Conclusion: The findings of the present study indicated a relatively strong correlation between inhalational exposure to styrene and the levels of mandelic acid in urine. In addition, smoking and working conditions, such as skin exposure and working hours per day, can affect the levels of urinary mandelic acid. Therefore, these factors should be considered in the exposure assessment of workers exposed to styrene.