An effective and rapidly degradable disinfectant from disinfection byproducts.

Chloroxylenol is a worldwide commonly used disinfectant. The massive consumption and relatively high chemical stability of chloroxylenol have caused eco-toxicological threats in receiving waters. We noticed that chloroxylenol has a chemical structure similar to numerous halo-phenolic disinfection byproducts. Solar detoxification of some halo-phenolic disinfection byproducts intrigued us to select a rapidly degradable chloroxylenol alternative from them. In investigating antimicrobial activities of disinfection byproducts, we found that 2,6-dichlorobenzoquinone was 9.0-22 times more efficient than chloroxylenol in inactivating the tested bacteria, fungi and viruses. Also, the developmental toxicity of 2,6-dichlorobenzoquinone to marine polychaete embryos decreased rapidly due to its rapid degradation via hydrolysis in receiving seawater, even without sunlight. Our work shows that 2,6-dichlorobenzoquinone is a promising disinfectant that well addresses human biosecurity and environmental sustainability. More importantly, our work may enlighten scientists to exploit the slightly alkaline nature of seawater and develop other industrial products that can degrade rapidly via hydrolysis in seawater.

A comparison of the performance of bacterial biofilters and fungal-bacterial coupled biofilters in BTEp-X removal.

Background: Conventional biofilters, which rely on bacterial activity, face challenges in eliminating hydrophobic compounds, such as aromatic compounds. This is due to the low solubility of these compounds in water, which makes them difficult to absorb by bacterial biofilms. Furthermore, biofilter operational stability is often hampered by acidification and drying out of the filter bed. Methods: Two bioreactors, a bacterial biofilter (B-BF) and a fungal-bacterial coupled biofilter (F&B-BF) were inoculated with activated sludge from the secondary sedimentation tank of the Sinopec Yangzi Petrochemical Company wastewater treatment plant located in Nanjing, China. For approximately 6 months of operation, a F&B-BF was more effective than a B-BF in eliminating a gas-phase mixture containing benzene, toluene, ethylbenzene, and para-xylene (BTEp-X). Results: After operating for four months, the F&B-BF showed higher removal efficiencies for toluene (T), ethylbenzene (E), benzene (B), and para-X (p-Xylene), at 96.9%, 92.6%, 83.9%, and 83.8%, respectively, compared to those of the B-BF (90.1%, 78.7%, 64.8%, and 59.3%). The degradation activity order for B-BF and F&B-BF was T > E > B > p-X. Similarly, the rates of mineralization for BTEp-X in the F&B-BF were 74.9%, 66.5%, 55.3%, and 45.1%, respectively, which were higher than those in the B-BF (56.5%, 50.8%, 43.8%, and 30.5%). Additionally, the F&B-BF (2 days) exhibited faster recovery rates than the B-BF (5 days). Conclusions: It was found that a starvation protocol was beneficial for the stable operation of both the B-BF and F&B-BF. Community structure analysis showed that the bacterial genus Pseudomonas and the fungal genus Phialophora were both important in the degradation of BTEp-X. The fungal-bacterial consortia can enhance the biofiltration removal of BTEp-X vapors.

High-performance activation of ozone by sonocavitation for BTEX degradation in water.

This work presents a novel advanced oxidation process (AOP) for degradation of emerging organic pollutants - benzene, toluene, ethylbenzene and xylenes (BTEXs) in water. A comparative study was performed for sonocavitation assisted ozonation under 40-120 kHz and 80-200 kHz dual frequency ultrasounds (DFUS). Based on the obtained results, the combination of 40-120 kHz i.e., low-frequency US (LFDUS) with O3 exhibited excellent oxidation capacity degrading 99.37-99.69% of BTEXs in 40 min, while 86.09-91.76% of BTEX degradation was achieved after 60 min in 80-200 kHz i.e., high-frequency US (HFDUS) combined with O3. The synergistic indexes determined using degradation rate constants were found as 7.86 and 2.9 for LFDUS/O3 and HFDUS/O3 processes, respectively. The higher extend of BTEX degradation in both processes was observed at pH 6.5 and 10. Among the reactive oxygen species (ROSs), hydroxyl radicals (HO•) were found predominant according to scavenging tests, singlet oxygen also importantly contributed in degradation, while O2•- radicals had a minor contribution. Sulfate (SO42-) ions demonstrated higher inhibitory effect compared to chloride (Cl-) and carbonate (CO32-) ions in both processes. Degradation pathways of BTEX was proposed based on the intermediates identified using GC-MS technique.

New perspectives on the anaerobic degradation of BTEX: Mechanisms, pathways, and intermediates.

Aromatic hydrocarbons like benzene, toluene, xylene, and ethylbenzene (BTEX) can escape into the environment from oil and gas operations and manufacturing industries posing significant health risks to humans and wildlife. Unlike conventional clean-up methods used, biological approaches such as bioremediation can provide a more energy and labour-efficient and environmentally friendly option for sensitive areas such as nature reserves and cities, protecting biodiversity and public health. BTEX contamination is often concentrated in the subsurface of these locations where oxygen is rapidly depleted, and biodegradation relies on anaerobic processes. Thus, it is critical to understand the anaerobic biodegradation characteristics as it has not been explored to a major extent. This review presents novel insights into the degradation mechanisms under anaerobic conditions and presents a detailed description and interconnection between them. BTEX degradation can follow four activation mechanisms: hydroxylation, carboxylation, methylation, and fumarate addition. Hydroxylation is one of the mechanisms that explains the transformation of benzene into phenol, toluene into benzyl alcohol or p-cresol, and ethylbenzene into 1-phenylethanol. Carboxylation to benzoate is thought to be the primary mechanism of degradation for benzene. Despite being poorly understood, benzene methylation has been also reported. Moreover, fumarate addition is the most widely reported mechanism, present in toluene, ethylbenzene, and xylene degradation. Further research efforts are required to better elucidate new and current alternative catabolic pathways. Likewise, a comprehensive analysis of the enzymes involved as well as the development of advance tools such as omic tools can reveal bottlenecks degradation steps and create more effective on-site strategies to address BTEX pollution.

The impact of ozone treatment on the removal effectiveness of various refractory compounds in wastewater from petroleum refineries.

Large volumes of wastewater are generated during petroleum refining processes. Petroleum refinery wastewater (PRW) can contain highly toxic compounds that can harm the environment. These toxic compounds can be a challenge in biological treatment technologies due to the effects of these compounds on microorganisms. These challenges can be overcome by using ozone (O3) as a standalone or as a pretreatment to the biological treatment. Ozone was used in this study to degrade the organic pollutants in the heavily contaminated PRW from a refinery in Mpumalanga province of South Africa. The objective was achieved by treating the raw PRW using ozone at different ozone treatment times (15, 30, 45, and 60 min) at a fixed ozone concentration of 3.53 mg/dm3. The ozone treatment was carried out in a 2-liter custom-designed plexiglass cylindrical reactor. Ozone was generated from an Eco-Lab-24 corona discharge ozone generator using clean, dry air from the Afrox air cylinder as feed. The chemical oxygen demand, gas chromatograph characterization, and pH analysis were performed on the pretreated and post-treated PRW samples to ascertain the impact of the ozone treatment. The ozone treatment was effective in reducing the benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds in the PRW. The 60-min ozone treatment of different BTEX pollutants in the PRW resulted in the following percentage reduction: benzene 95%, toluene 77%, m + p-xylene 70%, ethylbenzene 69%, and o-xylene 65%. This study has shown the success of using ozone in reducing the toxic BTEX compounds in a heavily contaminated PRW.

Evaluation of hemostatic, anti-inflammatory, wound healing, skin irritation and allergy, and antimicrobial properties of active fraction from the ethanol extract of Chromolaena odorata (L.) R.M. King & H. Rob.

ETHNOPHARMACOLOGICAL RELEVANCE: Chromolaenaodorata (L.) R.M. King & H. Rob, a perennial herb, has been traditionally utilized as a herbal remedy for treating leech bites, soft tissue wounds, burn wounds, skin infections, and dento-alveolitis in tropical and subtropical regions. AIM OF THE STUDY: The present study was to analyze the active fraction of C. odorata ethanol extract and investigate its hemostatic, anti-inflammatory, wound healing, and antimicrobial properties. Additionally, the safety of the active fraction as an external preparation was assessed through skin irritation and allergy tests. MATERIALS AND METHODS: The leaves and stems of C. odorata were initially extracted with ethanol, followed by purification through AB-8 macroporous adsorption resin column chromatography to yield different fractions. These fractions were then screened for hemostatic activity in mice and rabbits to identify the active fraction. Subsequently, the hemostatic effect of the active fraction was assessed through the bleeding time of the rabbit ear artery in vivo and the coagulant time of rabbit blood in vitro. The anti-inflammatory activity of the active fraction was tested on mice ear edema induced by xylene and rat paw edema induced by carrageenin. Furthermore, the active fraction's promotion effect on wound healing was evaluated using a rat skin injury model, and skin safety tests were conducted on rabbits and guinea pigs. Lastly, antimicrobial activities against two Gram-positive bacteria (G+, Staphylococcus aureus and S. epidermidis) and three Gram-negative bacteria (G-, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) were determined using the plate dilution method. RESULTS: The ethanol extract of C. odorata leaves and stems was fractionated into 30%, 60%, and 90% ethanol eluate fractions. These fractions demonstrated hemostatic activity, with the 30% ethanol eluate fraction (30% EEF) showing the strongest effect, significantly reducing bleeding time (P < 0.05). A concentration of 1.0 g/mL of the 30% EEF accelerated cutaneous wound healing in rats on the 3rd, 6th, and 9th day post-operation, with the healing effect increasing over time. No irritation or allergy reactions were observed in rabbits and guinea pigs exposed to the 30% EEF. Additionally, the 30% EEF exhibited mild inhibitory effect on mice ear and rat paw edema, as well as antimicrobial activity against tested bacteria, with varying minimal inhibitory concentration (MIC) values. CONCLUSIONS: The 30% EEF demonstrated a clear hemostatic effect on rabbit bleeding time, a slight inhibitory effect on mice ear edema and rat paw edema, significant wound healing activity in rats, and no observed irritation or allergic reactions. Antibacterial activity was observed against certain clinically isolated bacteria, particularly the G- bacteria. This study lays the groundwork for the potential development and application of C. odorata in wound treatment.

Risk assessment of Benzene, Toluene, Ethyl benzene, and Xylene (BTEX) in the atmospheric air around the world: A review.

Volatile organic compounds, such as BTEX, have been the subject of numerous debates due to their detrimental effects on the environment and human health. Human beings have had a significant role in the emergence of this situation. Even though US EPA, WHO, and other health-related organizations have set standard limits as unhazardous levels, it has been observed that within or even below these limits, constant exposure to these toxic chemicals results in negative consequences as well. According to these facts, various studies have been carried out all over the world - 160 of which are collected within this review article, so that experts and governors may come up with effective solutions to manage and control these toxic chemicals. The outcome of this study will serve the society to evaluate and handle the risks of being exposed to BTEX. In this review article, the attempt was to collect the most accessible studies relevant to risk assessment of BTEX in the atmosphere, and for the article to contain least bias, it was reviewed and re-evaluated by all authors, who are from different institutions and backgrounds, so that the insights of the article remain unbiased. There may be some limitations to consistency or precision in some points due to the original sources, however the attempt was to minimize them as much as possible.

Association between urinary BTEX metabolites and dyslexic odds among school-aged children.

Benzene, toluene, ethylbenzene, and xylene (BTEX) are ubiquitous in the environment, and all of them can cause neurotoxicity. However, the association between BTEX exposure and dyslexia, a disorder with language network-related regions in left hemisphere affected, remains unclear. We aimed to assess the relationship between BTEX exposure and dyslexic odds among school-aged children. A case-control study, including 355 dyslexics and 390 controls from three cities in China, was conducted. Six BTEX metabolites were measured in their urine samples. Logistic regression model was used to explore the association between the BTEX metabolites and the dyslexic odds. Urinary trans,trans-muconic acid (MU: a metabolite of benzene) was significantly associated with an increased dyslexic odds [odds ratio (OR) = 1.23, 95% confidence interval (CI): 1.01, 1.50], and the adjusted OR of the dyslexic odds in the third tertile was 1.72 (95% CI: 1.06, 2.77) compared to that in the lowest tertile regarding urinary MU concentration. Furthermore, the association between urinary MU level and the dyslexic odds was more pronounced among children from low-income families based on stratified analyses. Urinary metabolite levels of toluene, ethylbenzene, and xylene were not found to be associated with the dyslexic odds. In summary, elevated MU concentrations may be associated with an increased dyslexic odds. We should take measures to reduce MU related exposure among children, particularly those with low family income.

Effect of Dehulling Pretreatment on the Flavor of Sesame Paste.

Gas chromatography-olfactory-mass spectrometry (GC-O-MS) combined with Aroma Extract Dilution Analysis (AEDA) were employed to characterize the key odor-active compounds in sesame paste (SP) and dehulled sesame paste (DSP). The AEDA results revealed the presence of 32 and 22 odor-active compounds in SP and DSP, respectively. Furthermore, 13 aroma compounds with FD ≥ 2, OAV ≥ 1, and VIP ≥ 1 were identified as key differential aroma compounds between SP and DSP. Specifically, compounds such as 3-methylbutyraldehyde (OAV = 100.70-442.57; fruity), 2-methylbutyraldehyde (OAV = 106.89-170.31; almond), m-xylene (FD = 16; salty pastry), and 2,5-dimethylpyrazine (FD = 8-16; roasted, salty pastry) played an important role in this differentiation. Additionally, the dehulling process led to increased fermented, sweet, green, and nutty aroma notes in DSP compared to the more pronounced burnt and roasted sesame aroma notes in SP. Our findings offer a theoretical foundation for the regulation of sesame paste aroma profiles.

Exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) at Nigeria's petrol stations: a review of current status, challenges and future directions.

Introduction: In Nigeria, because of increasing population, urbanization, industrialization, and auto-mobilization, petrol is the most everyday non-edible commodity, and it is the leading petroleum product traded at the proliferating Nigeria's petrol stations (NPSs). However, because of inadequate occupational health and safety (OHS) regulatory measures, working at NPSs exposes petrol station workers (PSWs) to a large amount of hazardous benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. Methods: Studies on BTEX exposures among Nigerian PSWs are scarce. Thus, constraints in quantifying the health risks of BTEX limit stakeholders' ability to design practical risk assessment and risk control strategies. This paper reviews studies on the OHS of Nigerian PSWs at the NPSs. Results: Although knowledge, attitude, and practices on OHS in NPSs vary from one Nigeria's study setting to another, generally, safety practices, awareness about hazards and personal protective equipment (PPE), and the use of PPE among PSWs fell below expectations. Additionally, air quality at NPSs was poor, with a high content of BTEX and levels of carbon monoxide, hydrogen sulfide, particulate matter, and formaldehyde higher than the World Health Organization guideline limits. Discussion: Currently, regulatory bodies' effectiveness and accountability in safeguarding OHS at NPSs leave much to be desired. Understanding the OHS of NPSs would inform future initiatives, policies, and regulations that would promote the health and safety of workers at NPSs. However, further studies need to be conducted to describe the vulnerability of PSWs and other Nigerians who are occupationally exposed to BTEX pollution. More importantly, controlling air pollution from hazardous air pollutants like BTEX is an essential component of OHS and integral to attaining the Sustainable Development Goals (SDG) 3, 7, and 11.

Clearing Properties Between Coconut Oil and Xylene in Histological Tissue Processing.

Xylene is the commonest clearing agent even though it is hazardous and costly. This study evaluated the clearing properties of coconut oil as an alternative cost-effective clearing agent for histological processes. Ten (10) prostate samples fixed in formalin were taken and each one was cut into 4 before randomly separating them into four groups (A, B, C and D). Tissues were subjected to ascending grades of alcohol for dehydration. Group A was cleared in xylene and Groups B, C, and D were cleared at varying times of 1hr 30mins, 3hrs, and 4hrs in coconut oil respectively before embedding, sectioning, and staining were carried out. Gross and histological features were compared. Results indicated a significant shrinkage in coconut oil-treated specimen compared with the xylene-treated specimen and only the tissues cleared in coconut oil for 4hrs were as rigid as the tissues cleared in xylene (p > 0.05). No significant difference was found in either of the sections when checked for cellular details and staining quality (p > 0.999). Coconut oil is an efficient substitute for xylene in prostate tissues with a minimum clearing time of 4hrs, as it is environmentally friendly and less expensive, but causes significant shrinkage to prostate tissue.

Visualization of bone formation in sheep's middle ear by using fluorochrome sequential labelling (FSL).

One factor for the lacking integration of the middle ear stapes footplate prosthesis or the missing healing of stapes footplate fractures could be the known osteogenic inactivity. In contrast, it was recently demonstrated that titanium prostheses with an applied collagen matrix and immobilised growth factors stimulate osteoblastic activation and differentiation on the stapes footplate. Regarding those findings, the aim of this study was to evaluate the potential of bone regeneration including bone remodeling in the middle ear. Ten one-year-old female merino sheep underwent a middle ear surgery without implantation of middle ear prostheses or any other component for activating bone formation. Post-operatively, four fluorochromes (tetracycline, alizarin complexion, calcein green and xylenol orange) were administered by subcutaneous injection at different time points after surgery (1 day: tetracycline, 7 days: alizarin, 14 days: calcein, 28 days: xylenol). After 12 weeks, the temporal bones including the lateral skull base were extracted and histologically analyzed. Fluorescence microscopy analysis of the entire stapes with the oval niche, but in particular stapes footplate and the Crura stapedis revealed evidence of new bone formation. Calcein was detected in all and xylenol in 60% of the animals. In contrast, tetracycline and alizarin could only be verified in two animals. The authors were able to demonstrate the osseoregenerative potential of the middle ear, in particular of the stapes footplate, using fluorescence sequence labelling.

Association between volatile organic compounds and serum neurofilament light chain in US adults.

OBJECTIVE: This study aimed to investigate the associations between exposure to blood volatile organic compounds (VOCs) and the level of serum neurofilament light chain (NfL) in adults. METHODS: We analyzed data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES), including 2008 participants aged 20 to 75 years old. Multiple linear regression models were used to examine the associations between 28 VOCs and NfL after adjusting for multiple potential confounders. Restricted cubic spline (RCS) was used to examine the potential non-linear associations. RESULTS: The linear regression models showed that higher levels of 2,5-dimethylfuran (ß = 0.042, 95 % confidence interval [CI]: 0.001, 0.096), ethyl acetate (ß = 0.118, 95 % CI = 0.008, 0.304), and m-/p-xylene (ß = 0.043, 95%CI = 0.012, 0.074) were associated with higher NfL levels. These estimates were largely consistent after adjusting for multiple confounders. CONCLUSION: The findings of our study suggest a potential association between certain volatile organic compounds (2,5-dimethylfuran, ethyl acetate, and m-/p-xylene) and blood NfL levels, implying that they may have a role in revealing neurodegeneration and influencing neurological health.

Climatic conditions and concentrations of BTEX compounds in atmospheric media.

Climatic and meteorological conditions are among the factors affecting the ambient concentrations of BTEX compounds. This systematic review and meta-analysis aimed to interrogate the seasonal effect of climatic conditions on the concentrations of BTEX compounds. Three electronic bibliographic databases including Scopus, PubMed, and Web of Science were systematically searched up to November 14, 2023. The search algorithm followed PRISMA guidance and consisted of three groupings of keywords and their possible combinations. For various climatic conditions, the overall mean and 95% confidence interval (CI) of effect size related to BTEX concentrations were calculated using a random-effect model. In total, 104 articles were included for evaluation in this review. BTEX ambient concentration was higher in winter (ranging from 36 out of 79 relevant studies for xylene to 52 out of 97 relevant studies for benzene) followed by summer and autumn. For humidity conditions, the highest exposure values for BTEX were detected for rainy weather (ranging from 3 out of 5 relevant studies for toluene and xylene to 4 out of 5 relevant studies for benzene and ethyl benzene) compared to dry conditions. The pooled concentration (µg/m3) of benzene, toluene, ethyl benzene, and xylene were computed as 2.61, 7.12, 2.21, and 3.61 in spring, 2.13, 7.53, 1.61, and 2.75 in summer, 3.04, 9.59, 3.14, and 5.50 in autumn, and 3.56, 8.71, 2.35, and 3.91 in winter, respectively. Moreover, the pooled concentrations (µg/m3) of BTEX were measured as 2.98, 7.22, 1.90, and 3.03 in dry weather and 3.15, 6.30, 2.14, and 3.86 in rainy or wet weather, respectively. In most seasons, the ambient concentrations of BTEX were higher in countries with low and middle incomes and in Middle Eastern countries and East/Southeast Asia compared to those in other regions (P < 0.001). The increasing concentrations of BTEX in winter and autumn followed by the summer season and during rainy/wet weather appear to be reasonably consistent despite variations in study methods, quality, or geography. Therefore, it is recommended that more serious control measures are considered for decreasing exposure to BTEX in these climatic conditions.

The Impact of Environmental Benzene, Toluene, Ethylbenzene, and Xylene Exposure on Blood-Based DNA Methylation Profiles in Pregnant African American Women from Detroit.

African American women in the United States have a high risk of adverse pregnancy outcomes. DNA methylation is a potential mechanism by which exposure to BTEX (benzene, toluene, ethylbenzene, and xylenes) may cause adverse pregnancy outcomes. Data are from the Maternal Stress Study, which recruited African American women in the second trimester of pregnancy from February 2009 to June 2010. DNA methylation was measured in archived DNA from venous blood collected in the second trimester. Trimester-specific exposure to airshed BTEX was estimated using maternal self-reported addresses and geospatial models of ambient air pollution developed as part of the Geospatial Determinants of Health Outcomes Consortium. Among the 64 women with exposure and outcome data available, 46 differentially methylated regions (DMRs) were associated with BTEX exposure (FDR adjusted p-value < 0.05) using a DMR-based epigenome-wide association study approach. Overall, 89% of DMRs consistently exhibited hypomethylation with increasing BTEX exposure. Biological pathway analysis identified 11 enriched pathways, with the top 3 involving gamma-aminobutyric acid receptor signaling, oxytocin in brain signaling, and the gustation pathway. These findings highlight the potential impact of BTEX on DNA methylation in pregnant women.

Anti-inflammatory effects and related mechanisms in vitro and in vivo of Hedychium coccineum rhizome essential oil.

ETHNOPHARMACOLOGICAL RELEVANCE: Hedychium coccineum rhizome is an anti-inflammatory ethnomedicine used to remedy inflammation-related swelling and bronchial asthma. AIM OF THE STUDY: The study aimed to analyze the phytochemical constituents of H. coccineum rhizome essential oil (EO) and evaluate its in vitro and in vivo anti-inflammatory effects and underlying mechanisms. MATERIALS AND METHODS: Phytochemical constituents of H. coccineum rhizome EO were analyzed using GC-FID/MS. In RAW264.7 macrophages induced by LPS, blockade of PGE2, NO, IL-1ß, IL-6, and TNF-α secretion by H. coccineum rhizome EO was measured, and then Western blot, qRT-PCR, and immunofluorescent staining were used to evaluate its underlying mechanisms. Moreover, we used the xylene-induced ear edema model for testing anti-inflammatory potential in vivo and examined auricular swelling as well as tissue and serum contents of IL-1ß, IL-6, and TNF-α. RESULTS: EO's main components were E-nerolidol (40.5%), borneol acetate (24.8%), spathulenol (4.5%), linalool (3.8%), elemol (3.5%), and borneol (3.4%). In RAW264.7 cells stimulated by LPS, EO downregulated the expression of pro-inflammatory enzyme (iNOS and COX-2) genes and proteins, thereby suppressing pro-inflammatory mediators (NO and PGE2) secretion. Simultaneously, it reduced TNF-α, IL-1ß, and IL-6 release by downregulating their mRNA expression. Besides, H. coccineum EO attenuated LPS-stimulated activation of NF-κB (by reducing IκBα phosphorylation and degradation to inhibit NF-κB nuclear translocation) and MAPK (by downregulating JNK, p38, and ERK phosphorylation). In xylene-induced mouse ear edema, EO relieved auricular swelling and lowered serum and tissue levels of TNF-α, IL-1ß, and IL-6. CONCLUSIONS: H. coccineum EO had powerful in vivo and in vitro anti-inflammatory effects by inhibiting MAPK and NF-κB activation. Hence, H. coccineum EO should have great potential for application in the pharmaceutical field as a novel anti-inflammatory agent.

Synthesis and characterization of fluorescent poly(α-cyclodextrin)/carbon quantum dots composite for efficient removal and detection of toluene and xylene from aqueous media.

This study reports the synthesis and characterization of a supramolecular composite comprised of carbon dots (CDots) embedded within net-poly[(α-cyclodextrin)-ν-(citric acid)] (α-CD/CA/CDots) for the removal and detection of toluene and xylene from aqueous media. The remarkable stability of CDots within the composite enables the preservation of photoluminescence properties for prolonged storage and extended UV-light irradiation. As demonstrated, following the adsorption of both organic compounds, the composite detected them in the aqueous medium due to a fluorescence quenching mechanism. Spectroscopic analyses reveal that the accessible Stern-Volmer quenching constants for toluene and xylene are KSVa = 15.4 M-1 and KSVa = 10.3 M-1, respectively. As a result, the α-CD/CA/CDots composite were sensitive to the tested volatile organic compounds (LODtoluene = 3.7 mg/L and LODxylene = 4.9 mg/L). Optimal conditions for toluene and xylene adsorption were found, allowing to achieve noticeable adsorption capabilities (qe(toluene) = 68.9 and qe(xylene) = 48.2 mg/g) and removal efficiencies exceeding 70%. Different characterization techniques confirmed the successful synthesis of the composite and elucidated the interaction mechanisms between the adsorbent and the tested compounds. In summary, the multifunctionality demonstrated by the α-CD/CA/CDots composite ranks it as an efficient and promising adsorbent and detection probe for this class of water contaminants.

Ultrathin Parylene C-based sensitivity-gain nanoplasmonic sensor integrated on VCSEL for Aß42 detection.

As Alzheimer's disease prevalence continues to rise, there is an increasing demand for efficient on-chip biosensors capable of early biomarker detection. This study presents a novel biosensor chip leveraging vertical cavity surface emitting laser (VCSEL) technology, with Parylene C serving as the antibody coupling layer and utilizing a streamlined one-step antibody modification method. Integration of Parylene C enhances chip sensitivity from 34.28 µW/RIU to 40.32 µW/RIU. Moreover, post-testing removal of Parylene C enables chip reusability without significant alteration of results. The sensor demonstrates effective detection of Aß42, an Alzheimer's biomarker, exhibiting a linear range of 1-200 ng/mL and a detection limit of 0.26 ng/mL. These findings underscore the reusability and reliability of the ultrathin Parylene C-based VCSEL biosensor chip, highlighting its potential for point-of-care Alzheimer's disease diagnosis.

Versatile ferrous oxidation-xylenol orange assay for high-throughput screening of lipoxygenase activity.

Lipoxygenases (LOXs) catalyze dioxygenation of polyunsaturated fatty acids (PUFAs) into fatty acid hydroperoxides (FAHPs), which can be further transformed into a number of value-added compounds. LOXs have garnered interest as biocatalysts for various industrial applications. Therefore, a high-throughput LOX activity assay is essential to evaluate their performance under different conditions. This study aimed to enhance the suitability of the ferrous-oxidized xylenol orange (FOX) assay for screening LOX activity across a wide pH range with different PUFAs. The narrow linear detection range of the standard FOX assay restricts its utility in screening LOX activity. To address this, the concentration of perchloric acid in the xylenol orange reagent was adjusted. The modified assay exhibited a fivefold expansion in the linear detection range for hydroperoxides and accommodated samples with pH values ranging from 3 to 10. The assay could quantify various hydroperoxide species, indicating its applicability in assessing LOX substrate preferences. Due to sensitivity to pH, buffer types, and hydroperoxide species, the assay required calibration using the respective standard compound diluted in the same buffer as the measured sample. The use of correction factors is suggested when financial constraints limit the use of FAHP standard compounds in routine LOX substrate preference analysis. FAHP quantification by the modified FOX assay aligned well with results obtained using the commonly used conjugated diene method, while offering a quicker and broader sample pH range assessment. Thus, the modified FOX assay can be used as a reliable high-throughput screening method for determining LOX activity. KEY POINTS: • Modifying perchloric acid level in FOX reagent expands its linear detection range • The modified FOX assay is applicable for screening LOX activity in a wide pH range • The modified FOX assay effectively assesses substrate specificity of LOX.

Co-exposure of petrochemical workers to noise and mixture of benzene, toluene, ethylbenzene, xylene, and styrene: Impact on mild renal impairment and interaction.

Epidemiological evidence concerning effects of simultaneous exposure to noise and benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) on renal function remains uncertain. In 2020, a cross-sectional study was conducted among 1160 petrochemical workers in southern China to investigate effects of their co-exposure on estimated glomerular filtration rate (eGFR) and mild renal impairment (MRI). Noise levels were assessed using cumulative noise exposure (CNE). Urinary biomarkers for BTEXS were quantified. We found the majority of workers had exposure levels to noise and BTEXS below China's occupational exposure limits. CNE, trans, trans-muconic acid (tt-MA), and the sum of mandelic acid and phenylglyoxylic acid (PGMA) were linearly associated with decreased eGFR and increased MRI risk. We observed U-shaped associations for both N-acetyl-S-phenyl-L-cysteine (SPMA) and o-methylhippuric acid (2-MHA) with MRI. In further assessing the joint effect of BTEXS (ß, -0.164 [95% CI, -0.296 to -0.033]) per quartile increase in all BTEXS metabolites on eGFR using quantile g-computation models, we found SPMA, tt-MA, 2-MHA, and PGMA played pivotal roles. Additionally, the risk of MRI associated with tt-MA was more pronounced in workers with lower CNE levels (P = 0.004). Multiplicative interaction analysis revealed antagonisms of CNE and PGMA on MRI risk (P = 0.034). Thus, our findings reveal negative dose-effect associations between noise and BTEXS mixture exposure and renal function in petrochemical workers. With the exception of toluene, benzene, xylene, ethylbenzene, and styrene are all concerning pollutants for renal dysfunction. Effects of benzene, ethylbenzene, and styrene exposure on renal dysfunction were more pronounced in workers with lower CNE.