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Nerve agents represent a serious threat to security worldwide. Chemical terrorism has become an alarming danger since the technological progresses have simplified the production of nerve agents. Therefore, there is an immediate demand for a fast and precise detection of these compounds on-site and real-time. In this perspective, Surface-Enhanced Raman Scattering (SERS) has emerged as a well-suited alternative for on-field detection.SERS performances of unfunctionalized SERS substrates were evaluated in realistic samples. Two nerve agents, Tabun and VX, were diluted in two matrix models: a contact lens solution, and a caffeine-based eye serum. The performance two research-grade instruments and two portable devices were compared. Despite the use of a small sampling volume of complex matrices without any sample pre-treatment, we achieved Tabun detection in both media, with a practical limit of detection (LOD) in the range of 7–9 ppm in contact lens liquid, and of 10.2 ppm in eye serum. VX detection turned out to be more challenging and was achieved only in contact lens solution, with a practical LOD in the range of 0.6–5 ppm.These results demonstrate the feasibility of on-field detection of nerve agents with SERS, that could be implemented when there is suspicion of chemical threat.

Nerve agents represent a serious threat to security worldwide. Chemical terrorism has become an alarming danger since the technological progresses have simplified the production of nerve agents. Therefore, there is an immediate demand for a fast and precise detection of these compounds on-site and real-time. In this perspective, Surface-Enhanced Raman Scattering (SERS) has emerged as a well-suited alternative for on-field detection. SERS performances of unfunctionalized SERS substrates were evaluated in realistic samples. Two nerve agents, Tabun and VX, were diluted in two matrix models: a contact lens solution, and a caffeine-based eye serum. The performance two research-grade instruments and two portable devices were compared. Despite the use of a small sampling volume of complex matrices without any sample pre-treatment, we achieved Tabun detection in both media, with a practical limit of detection (LOD) in the range of 7-9 ppm in contact lens liquid, and of 10.2 ppm in eye serum. VX detection turned out to be more challenging and was achieved only in contact lens solution, with a practical LOD in the range of 0.6-5 ppm. These results demonstrate the feasibility of on-field detection of nerve agents with SERS, that could be implemented when there is suspicion of chemical threat., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Giulia Zappalà reports equipment, drugs, or supplies was provided by Swedish Defence Research Agency. Giulia Zappalà reports equipment, drugs, or supplies was provided by Silmeco ApS. Anja Boisen has patent Surface enhanced Raman scattering substrates consumables for Raman spectroscopy licensed to Technical University of Denmark. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Flavonoids are a kind of secondary metabolite which widely exist in plants. They contain a lot of active hydroxyls, which can react with toxic chemicals to produce potential exposure biomarkers. In this article, the model plant Arabidopsis thaliana (L.) was exposed to the nerve agent O-Ethyl N,N-dimethyl phosphoramidocyanidate (Tabun). By comparing with the plant not exposed to Tabun, some characteristic ions were identified by quadrupole–time of flight mass spectrometry in the acetonitrile extract of the exposed leaves. These characteristic ions were selected as parent ions to produce product ion mass spectra (PIMS). Some interesting fragmentation pathways were revealed, including neutral loss of glucoside, rhamnose and ethylene. O-Ethyl N,N-dimethyl phosphoryl modified flavonoids were deduced from assignment of the PIMS. The element components and the accurate mass of the product ions from each parent ion matched well with those of the proposed fragmentation pathways. Through comparison with the PIMS of structurally closely related chemical of Isobutyl methylphosphonyl modified flavonoids, the structures and the fragmentation pathways of the O-Ethyl N,N-dimethyl phosphoryl modified flavonoids were finally confirmed. Successfully finding and identifying these three specific exposure biomarkers in plants provided a new strategy for the retrospective analysis of organophosphorus exposure and forensic analysis.

In the presence of the tabun mimic diethylcyanophosphonate (DECP), a fluorescent bifunctional coumarin–enamine chemodosimeter is first phosphorylated and subsequently attacked by the released cyanide ions. The reaction is disclosed in both the UV-vis and fluorescence spectra and confirmed by NMR experiments. DFT calculations support that the bis-adduct as the most thermodynamically stable species. The X-ray structure of the chemodosimeter is also reported. [ABSTRACT FROM AUTHOR]

Summary: Nerve agents that irreversibly deactivate the enzyme acetylcholinesterase are extremely toxic weapons of mass destruction. Thus, developing methods to detect these lethal agents is important. To create an optical sensor for a surrogate of the nerve agent tabun, as well as a physical barrier that dissolves in response to this analyte, we devise a network hydrogel that decomposes via a self-propagating cascade. A Meldrums acid-derived linker is incorporated into a hydrogel that undergoes a declick reaction in response to thiols, thereby breaking network connections, which releases more thiols, propagating the response throughout the gel. A combination of chemical reactions triggered by the addition of the tabun mimic initiates the cascade. The dissolving barrier is used to release dyes, as well as nanocrystals that undergo a spontaneous aggregation. Thus, this sensing system for tabun generates a physical response and the delivery of chemical agents in response to an initial trigger.

Selective optical detection of highly toxic nerve agents and their mimics like diethyl cyanophosphate (DCNP) is of paramount importance for armed forces and first responders in order to decide the suitable medical countermeasures. The reported optical chemical sensors for DCNP suffered from poor selectivity due to their single point covalent interaction with analyte. To overcome this limitation, we herein, report a novel protocol utilizing a ditopic chemodosimeter which, in presence of tetrabutylammonium hydroxide (TBAOH), underwent dual interaction with reactive subunits of DCNP, viz., electrophilic phosphorus and cyanide, to induce unique changes in its fluorescence as well as colorimetric properties. Other interfering analytes could not trigger the similar optical response in the sensing probe due to the absence of electrophilic phosphorus and cyanide. A truth table was constructed to reveal that only DCNP but not other analytes could induce changes in both fluorescence as well as colorimetric properties of sensing probe. The linearity range of the proposed method was found to be 30–70 μM while chromogenic limit of detection (LOD) was calculated to be 99 nM which are comparable to the reported methods. Thus, use of indigenously available 2‐hydroxy‐1‐naphthaldehyde as sensing probe without requiring further chemical manipulation represented a significant improvement over the literature methods for DCNP sensing. [ABSTRACT FROM AUTHOR]

This study aims to determine "How is the development of teaching materials with the context of traditional Dayak tabun hunting tools in the flat-sided building material for class VIII students of SMP Negeri 01 Ketungau Tengah". With sub-problems or problems, especially in this study, how is the level of validity, practicality, and effectiveness of teaching materials in the context of traditional Dayak tabun hunting tools in the material for building flat-sided spaces in class? VIII students of SMP Negeri 01 Ketungau Tengah. The method used in this study is the Research & Development (R&D) research method concerning the 4-D model, namely Define, Design, Development, and Disseminate. The test subjects in this study were class VIII students of SMP Negeri 01 Ketungau Tengah, with 29 students. Based on the results of the limited trials conducted, it was found that 1) the results of the validation of teaching materials were 80.79% in the excellent category, 2) the results of practicality based on observations of the implementation of the teaching materials developed were 84.37% in the practical category, 3) the results of the effectiveness of the materials. Teaching is 68.96 % with effective category. So, it can be concluded that in the limited trial stage, mathematics teaching materials in the context of traditional Dayak tabun hunting tools have met the criteria of validity, practicality, and effectiveness

Aim: The comparison of neuroprotective and central reactivating effects of the oxime K870 in combination with atropine with the efficacy of standard antidotal treatment in tabun-poisoned rats. Methods: The neuroprotective effects of antidotal treatment were determined in rats poisoned with tabun at a sublethal dose using a functional observational battery 2 h and 24 h after tabun administration, the tabun-induced brain damage was investigated by the histopathological evaluation and central reactivating effects of oximes was evaluated by the determination of acetylcholinesterase activity in the brain using a standard spectrophotometric method. Results: The central reactivating efficacy of a newly developed oxime K870 roughly corresponds to the central reactivating efficacy of pralidoxime while the ability of the oxime HI-6 to reactivate tabun-inhibited acetylcholinesterase in the brain was negligible. The ability of the oxime K870 to decrease tabun-induced acute neurotoxicity was slightly higher than that of pralidoxime and similar to the oxime HI-6. These results roughly correspond to the histopathological evaluation of tabun-induced brain damage. Conclusion: The newly synthesized oxime K870 is not a suitable replacement for commonly used oximes in the antidotal treatment of acute tabun poisonings because its neuroprotective efficacy is only slightly higher or similar compared to studied currently used oximes.

The purpose of this study was to describe ethnomathematics on Dayak Tabun traditional tools in school mathematics learning. This study uses a qualitative approach, with descriptive research methods. Observation techniques are direct observation and communication techniques, namely interviews with Dayak Tabun community leaders, especially makers, users, and traditional stakeholders. the results of the research obtained are: 1) form, learning context in geometric concepts, namely flat and wake up space; 2) aspects of the motive, the learning context in the geometry concepts, like are two-dimensional, lines, and angles, besides that the algebraic concept is a number pattern in the form of a constant sequence; 3) the way of making, the learning context in the algebraic concept of numbers, namely fractions in dividing the material into two parts, calculating operations especially on natural numbers, sequential numbers through measurement of materials; 4) in terms of the use of tools, the context of calculating operating learning is the tool used in the dance, namely the tapping of movements and elevation angles in trigonometric material, namely the use of a Sangkuh Akai tool. Therefore, ethnomathematics on traditional Dayak Tabun ethnic instruments can be used as the context of school mathematics learning.

Flavonoids are a kind of secondary metabolite which widely exist in plants. They contain a lot of active hydroxyls, which can react with toxic chemicals to produce potential exposure biomarkers. In this article, the model plant Arabidopsis thaliana (L.) was exposed to the nerve agent O-Ethyl N , N -dimethyl phosphoramidocyanidate (Tabun). By comparing with the plant not exposed to Tabun, some characteristic ions were identified by quadrupole-time of flight mass spectrometry in the acetonitrile extract of the exposed leaves. These characteristic ions were selected as parent ions to produce product ion mass spectra (PIMS). Some interesting fragmentation pathways were revealed, including neutral loss of glucoside, rhamnose and ethylene. O-Ethyl N , N -dimethyl phosphoryl modified flavonoids were deduced from assignment of the PIMS. The element components and the accurate mass of the product ions from each parent ion matched well with those of the proposed fragmentation pathways. Through comparison with the PIMS of structurally closely related chemical of Isobutyl methylphosphonyl modified flavonoids, the structures and the fragmentation pathways of the O-Ethyl N,N -dimethyl phosphoryl modified flavonoids were finally confirmed. Successfully finding and identifying these three specific exposure biomarkers in plants provided a new strategy for the retrospective analysis of organophosphorus exposure and forensic analysis.