Winnicott (1945a) suggested that some types of aggressive behaviour of the child returning from sustained separation from their parents may be regarded as an expression of hope, one in which they can yield their forms of defensive self-sufficiency to trust a parent again. The author parses Winnicott's later various approaches to understanding both instinctual and reactive aggression and how applying his later views can obfuscate the meaning of aggression in nuisance-making behaviour. The author offers a specific definition of nuisance in the analysis of adults and how it manifests itself in the analytic context. In the adult patients he describes, anger and hostility have become featured as expressions of grievance or greed regarding earlier ruptures in an experience of the parent's or analyst's registration of the patient's needs for attention. He considers two clinical contexts involving the conscious reluctance to agree with the analyst's interpretations as well as making demands on the analyst outside the setting as forms of nuisance. He explores how the analyst needs to hold two psychic realities - the patient's hope that is expressed in their nuisance-making as well as the analyst's limits in absorbing the patient's own self-destructive hatred of dependency. Holding these two realities helps to transform these self-destructive bids for attention into an opportunity for mourning. The analyst is required to work with his or her own subtle experiences of disturbance including hostility, helplessness and the pull to act out roles in the patient's earlier life.
This study presents a robust, green, sustainable and time-efficient approach for the simultaneous determination of Bupropion HCl (BUP) and Dextromethorphan HBr (DEX) along with their related impurities 3-Chlorobenzoic acid and N, N-Dimethylaniline. Principal component regression (PCR) and partial least-squares (PLS), in addition to advanced chemometric models, namely multivariate curve resolution-alternating least squares (MCR-ALS), and artificial neural networks (ANN), are the four green smart multivariate spectrophotometric models that were proposed and validated. The suggested models were successful in examining the mixture of BUP and DEX in the presence of their impurities. Therefore, the suggested analytical methods can be applied to pharmaceutical formulation analysis without the need for a separation step. The proposed strategy offers a novel analytical platform for quality control laboratories to manage complex formulations involving interfering substances. To further ensure greenness and sustainability of the proposed approach, several assessment tools were applied, including the Modified National Environmental Methods Index (NEMI), Eco-Scale, the Analytical GREEnness (AGREE) metric, the Hexagon algorithm, the Green Analytical Procedure Index (GAPI), the Modified GAPI (MoGAPI), the Blue Applicability Grade Index (BAGI), White Analytical Chemistry (WAC), and the Click Analytical Chemistry Index (CACI). Many traditional analytical techniques pose undesirable dangers to the environment and the analyst, such as using hazardous solvents. This gave analysts the incentive to use green methodologies that take into account the use of safe chemicals, the production of the least amount of trash, substantial time savings, and enhanced analyst safety.
Sophocles' Oedipus Rex and Oedipus at Colonus explore opposing conceptions of free will and moral responsibility. The first posits that individuals sometimes possess the freedom to act otherwise, making them backward-looking morally responsible for their actions. The second argues that humans lack such freedom; thus, their behavior is theoretically predictable, rendering them only forward-looking morally responsible. This paper suggests that these two views create an interpsychic conflict between the drive to control-satisfied by the first view, which implies we control our actions to act otherwise-and the epistemophilic drive-satisfied by the second view, which offers determinants of our behavior that can be known. By examining clinical situations, two responses to this conflict are presented: Some subjects pursue knowledge of their inner necessities, thereby weakening persecutory guilt tied to backward-looking responsibility; others resist such knowledge to preserve their sense of control. This dynamic unfolds in the transference-countertransference relationship when the analyst's position shifts from one of the triangular Oedipal roles to a fourth position-the oracle, who intimately knows one's internal necessities.
Herein, we present a sensitive and straightforward photothermal-based paper analytical device (PT-PAD) for quantifying mercury ions (Hg2+) in drinking water and Wolffia samples, facilitating rapid screening of the quality of aquatic plants in association with environmental water. The technique involves the etching reaction of silver nanoparticles (AgNPs) with Hg2+ on the paper substrate, which leads to a change in their photothermal conversion. The Hg2+ levels can be detected by monitoring the temperature change under irradiation with a 405 nm laser pointer. The sensor established a working linear range between 3.0 and 11.0 ppb with a detection limit (LOD) of 0.06 ppb. Furthermore, it offers remarkable precision with a maximum relative standard deviation (RSD) of 7.3%. Likewise, there were no significant interference effects from both anions and cations, indicating high selectivity for Hg2+ monitoring. The proposed method exhibits excellent accuracy and precision for detecting Hg2+ levels in drinking water and Wolffia samples, with a recovery range of 96.0-104.0% and the highest RSD of 4.4%. These results are compatible with those obtained by the inductively coupled plasma mass spectrometry (ICP-MS) method. Despite not using complex instruments, the assay shows a greater detection performance compared to most of the previous microfluidic paper-based analytical devices (µPADs). Overall, our developed PT-PAD sensor provides a promising approach for the sensitive detection of Hg2+ levels in both drinking water and Wolffia samples and could be extended to monitor other samples with outstanding detection capability. Moreover, the concept of etching-induced photothermal analysis can be applied to other analytes, making this highly sensitive method suitable for future sensing development.
In vitro cell models of the gut epithelium, particularly those based on the Caco-2 and HT29-MTX cell lines, play an important role in studying the uptake and metabolism of nutrients and pharmaceuticals. Previous studies using mass spectrometry imaging have shown a distinctive lipidome signature for these cells, alone and in coculture, although only limited information on lipid identities was obtained. A novel method employing limited proteolysis for sampling live, adherent cells using an automated capillary extraction workflow was developed which achieved single-cell sampling of Caco-2 cells although only clusters of HT29-MTX cells could be sampled due to mucus secreted by these cells. The lipidomes of the cell samples were mapped using LC-MS/MS and approximately 150 lipids were putatively identified. Further analysis of these data confirmed the distinctiveness of the Caco-2 and HT29-MTX cell lipidomes. Cell-to-cell heterogeneity was observed, especially in the Caco-2 cells, which may be indicative of variation in their differentiation state. Metabolic pathway analysis showed the distinctive lipidome of Caco-2 cells related to increased glycerol-3-phosphate pathway activity involved in di- and tri- glyceride synthesis. In contrast, HT29-MTX cells exhibited a more active phosphatidylcholine metabolism, related to their mucus-secreting capability. Future studies will explore wider application of the sampling procedure outlined here for single cell lipidomics of other adherent cell lines.
Bloodstain pattern analysis (BPA) is performed as part of forensic crime scene investigations to classify and interpret bloodstains in the context of the crime scene. HemoVision is a BPA computer software package that automates the documentation, analysis, and visualization of bloodstain patterns. This study aimed to assess the accuracy of HemoVision's beta cast-off bloodstain pattern analysis feature. A wooden rig with a circular swing path was used to create 36 controlled cast-off bloodstain patterns with downward vertical, upward vertical, and downward diagonal swings. Of these tests, six were conducted as blind trials where the analyst was absent for the bloodstain pattern creation. HemoVision estimated the x, y, and z axis positions of the center of swing and the radius of swing, which were compared to the known values. The average absolute errors of the estimated three-dimensional center of swing were determined to be 16.2 ± 6 cm, 27.3 ± 9 cm, 16.6 ± 8 cm, and 12.2 ± 5 cm for the downward, upward, diagonal, and blind swing trials, respectively. It was determined that the x position (horizontal) was the most accurate and the y position (vertical) the least accurate. Furthermore, the cast-off swing path was estimated in HemoVision as a curved tubular shape with a diameter of 3σ, referred to as the tubular swing path envelope (TSPE). In all cases, the known swing path was partially or fully contained within the TSPE. Thus, HemoVision BPA can accurately estimate an area in which the bloody weapon was swung through.
The pulmonary toxicant, ketene, has been observed from electronic (e-) cigarette vaping and dabbing (flash vaporisation) of acetylated compounds such as Vitamin E Acetate (VEA) and the O-acetates of select few cannabinoids. Yet for the majority of commercially-available cannabinoids with structural similarities to VEA, toxicant yields from vaping have not been quantified. Methodology optimisation for ketene trapping and quantification or characterisation of the co-production of other potentially harmful products have not been reported. In this work, an optimised impinger collection method was used to quantify the yield of ketene and carbonyl products from several conventional and emerging cannabinoid distillates using a commercially available cannabis e-cigarette. Ketene and carbonyls were analysed after chemical derivitisation by high performance liquid chromatography high-resolution mass spectrometry (HPLC-HRMS) and cannabinoids were analysed using gas chromatography mass spectrometry (GC-MS). The cannabinoids under study are: delta-8 tetrahydrocannbinol O-acetate (Δ8-THCO), delta-9 tetrahydrocannbinol O-acetate (Δ9-THCO), cannabidiol di-O-acetate (CBD-di-O), cannabigerol di-O-acetate (CBG-di-O), 9(R)-hexahydrocannabinol O-acetate (HHCO) and their paired non-acetylated analogues (Δ8-THC, Δ9-THC, CBD, CBG, and HHC). The acetyl group decomposed into ketene during vaping with nearly quantitative efficiency (>99%). No ketene was observed in the unvaped distillates or during vaping of the the non-acetylated cannabinoids. The highest summed production of ketene and carbonyl was observed from CBD-di-O which was attributed to the presence of two O-acetate groups on the phenyl moeity and the reactive exo-cyclic double bond of the terpene side chain. Higher airflow through the device due to opening the vent reduced ketene yields but increased carbonyl yields, showcasing that temperature and oxygen influence the distribution of these toxicants. Cannabis vape users can oscillate between open and closed air vents, which modify their toxicant exposure. Overall, ketene and carbonyl production yields from O-acetylated cannabinoids ranged between 1-4% and 0.1-1.5%, respectively, by cannabinoid mass. The carbonyl production yields for non-acetylated cannabinoids ranged between 0.1-7% by cannabinoid mass. These optimised measurements show that vape users can be exposed to yields of toxicants that far exceed safety limits for pulmonary effects, and therefore, further stringent product regulation is required to avoid health implications from vaping.
The coastal zone is a critical interface between terrestrial and marine systems, providing ecosystem services and economic value while serving as a major sink for land-derived contaminants. The identification and quantification of new pollutants (NPs), particularly antibiotics, even as trace residues, in coastal environments are necessary owing to their potential ecological and human-health risks. Given the complex, high-salinity matrices of samples from coastal zones and their low analyte concentrations, efficient sample pretreatments for cleanup and enrichment are required. Metal-organic framework-based molecularly imprinted polymers (MOF-MIPs), integrating the high porosity and surface area of MOFs with the molecular recognition ability of MIPs, have become promising sorbents for solid-phase extraction (SPE). Herein, a core-shell ZIF-8@MIP composite was facilely synthesized via surface imprinting and one-pot precipitation polymerization using ciprofloxacin (CIP) as the template and the ZIF-8 MOF as the core. The morphology, structure and composition of the composite were well characterized, and the adsorption equilibrium could be reached within 30 min, with a high maximum adsorption capacity of 151.96 mg g-1. Then, the ZIF-8@MIPs-based dispersive SPE (DSPE) coupled with HPLC-UV was developed for the simultaneous enrichment and determination of six fluoroquinolone antibiotics (FQs) in coastal zone water and biological samples. Under optimized conditions, low limits of detection of 0.060-1.440 μg L-1 and limits of quantification of 0.201-4.799 μg L-1 were achieved. Spiked recoveries in beach seawater, aquaculture wastewater, river water, and biological samples (pomfret and prawn) ranged from 92.6% to 118.9%, with relative standard deviations (RSDs) within 0.2%-6.1%. The present DSPE-HPLC study offers a simple and alternative method for NP analysis in coastal samples and could enrich the research scope of MOF-MIP-based sample pretreatment.
This work introduces an environmentally benign route for producing strongly blue-emissive graphene quantum dots (GQDs) from graphene oxide synthesized via a modified Tour method. GQDs are nanoscale (<10 nm) fragments of graphene known for their excellent biocompatibility, photostability, and tunable fluorescence properties. The resulting graphene oxide and GQDs were meticulously examined using UV-vis spectroscopy, FTIR, PXRD, FESEM and TEM. Leveraging their exceptional optical properties, the GQDs were employed to construct a highly sensitive and selective fluorometric platform for the detection of two eco-hazardous nitroaromatic pollutants, para-nitroaniline (PNA) and 2,4,6-trinitrophenol (TNP). The sensing system exhibited impressive analytical performance, achieving low optical detection limits of 0.217 µM for PNA and 0.108 µM for TNP. The fluorescence quenching of GQDs by TNP and PNA is governed by the inner filter effect, accompanied by a static quenching component arising from ground-state complex formation. Beyond their sensing capability, the GQDs were evaluated for ecological safety through a nanophytotoxicity assay using mung bean (Vigna radiata L.) seeds. Although quantum dots are generally considered non-toxic within the research community, no comprehensive studies have examined their effects on seed germination. Addressing this major research gap, our investigation reveals that at sufficiently high concentrations, quantum dots can in fact inhibit seed germination. In contrast, the GQDs used in this study exhibited negligible nanophytotoxicity across a broad concentration range, confirming their strong environmental compatibility. Moreover, when applied as nanoprobes, the working concentrations required are extremely low, rendering them effectively non-toxic. Overall, this work not only introduces GQDs as green, efficient nanosensors but also establishes their value as a platform for assessing the broader environmental implications of quantum-dot-based technologies.
Photoactive molecules are of central interest due to their roles in light-matter interaction and in biological systems, and their applications in technology and medicine. Many important photoactive molecules undergo photodegradation, which is a complex, multi-path process involving many molecular species. One compelling case of photodecomposition involves retinyl acetate, which is necessary for vision processes. Here, we demonstrate a comprehensive approach in which the informativity of NMR can be harnessed for the in-depth investigation of the way in which photodegradation proceeds via a combination of two approaches: the interleaved time-resolved non-uniform sampling and time-resolved diffusion NMR. Specifically, the mass evolution, which was estimated from the first approach, was compared with the mass calculated from the diffusion coefficient estimated from the second approach, and the correlation between them was identified, enabling NMR signal assignment. This comparison is used for the Monte Carlo-like assignment, in which a vast library of potential reactants is scanned to determine the proper assignment. The presented approach is general-purpose and can be easily implemented for the investigation of many important photodegradation processes.
Lateral flow immunoassays (LFIAs) coupled to surface enhanced Raman scattering (SERS) measurements can produce quantitative outputs with excellent sensitivity. Despite this, they have not been adopted into point-of-care (POC) scenarios, due to the perceived lack of reproducibility and stability in SERS measurements over time. To address this, the performance, stability and reproducibility of a newly developed SERS-LFIA designed for the detection of liver injury has been assessed to investigate if the tests could yield the same results six-months after preparation. The SERS-LFIA incorporated silica coated Raman active gold nanoparticles to increase the stability when used with human serum samples and the SERS signals of the test and control lines were analysed using a handheld Raman reader to mimic its use at the POC. The relative standard deviations of key metrics, including reproducibility and variation in signal were assessed over the course of a 6 month stability study using a range of methods that aimed to standardise the output. Test line intensity, test/control ratio and slope linear regression outputs were all used to assess the SERS-LFIA results with the best reproducibility being achieved when normalising the test via the slope linear regression method. After 5 months the output only decreased by 11% for a sample spiked with a clinically relevant concentration of liver injury biomarker, demonstrating the test was still performing as intended. Overall, we have shown that SERS-LFIA can produce similar outputs after 5 months of storage at room temperature demonstrating their stability and robustness.
Gas chromatography (GC) using porous layer open tubular (PLOT) columns provides an accessible approach for the analysis of permanent gases in environmental samples and gaseous processes. However, unlike that in GC of volatile liquids, solvent effects cannot be readily exploited for permanent gas samples. This limitation arises from the low boiling points of permanent gases and the incompatibility of PLOT columns with conventional high-boiling-point solvents. Here, we report an unexpected solvent-like effect of a non-reactive permanent gas (as "solvent") on the separation of permanent gas analytes. When argon-typically inferior to costly helium or less-safe hydrogen in separation efficiency-is used as the carrier gas, the co-injection of "solvent" permanent gases enhances the chromatographic resolution of analytes. Specifically, the addition of helium, hydrogen, carbon dioxide, carbon monoxide, or methane to oxygen-nitrogen mixtures significantly improves the resolution of oxygen and nitrogen in ambient air samples. Column modification experiments with carbon dioxide, together with in-column "band-passing" of helium over oxygen and nitrogen, indicate that the enhanced separation efficiency arises from the co-injection of the analyte and "solvent" gases. This behavior is attributed to two possible contributing mechanisms: (i) a transient pressure drop associated with strongly adsorbing solvent gases (carbon dioxide, methane, and carbon monoxide) and (ii) the temporary role of helium and hydrogen as auxiliary carrier gases, which increase column efficiency while consuming minimal quantities of these gases.
Generally, unstable metal-organic frameworks (MOFs) have been less commonly employed in many applications compared to stable MOFs. However, given the vast number of such unstable MOFs and the diversity of their instability behaviors, exploring their effective utilization is both necessary and significant. Unlike previous reports, this work mainly focused on the specific instability of Cu-BTC towards thiocholine, which was generated through the enzymatic hydrolysis of acetylthiocholine chloride (ATCl) by acetylcholinesterase (AChE). In detail, Cu-BTC exhibited outstanding peroxidase-like activity, efficiently catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) into its oxidized form, generating a strong UV-vis absorption peak at 655 nm. Upon the addition of AChE and its substrate ATCl, the substrate was hydrolyzed by AChE to yield thiocholine (TCl), which triggered the disintegration of Cu-BTC, thereby inhibiting TMB oxidation. As expected, based on the thiocholine-induced disintegration of Cu-BTC, the sensor enabled the selective and sensitive visual detection of the AChE inhibitor chlorpyrifos with a low detection limit of 8.95 pM. This method was successfully applied to pesticide analysis in spiked vegetable samples, achieving recoveries ranging from 98.83% to 109.81% with relative standard deviations below 2.57%. The proposed strategy not only provides a simple and visual approach for food safety monitoring but also opens new possibilities for exploiting unstable MOFs as smart sensing platforms.
Adenosine triphosphate (ATP) is an important extracellular signaling molecule in the human body. Its abnormal expression is closely related to the occurrence and development of various diseases, and accurate detection is of great significance for early disease diagnosis. However, conventional photoelectrochemical (PEC) sensors still suffer from low visible-light utilization, serious recombination of photogenerated carriers and limited detection sensitivity, making it difficult to achieve accurate detection of low-abundance ATP. In this work, an enzyme-catalyzed PEC aptasensor based on a CdIn2S4/ZnSnO3 (CIS/ZSO) heterojunction was constructed. The heterojunction significantly enhances visible-light absorption and promotes the separation and transport of photogenerated carriers, with a photocurrent response approximately 10 times higher than that of pure CdIn2S4. In the presence of 3,3'-diaminobenzidine (DAB) and hydrogen peroxide (H2O2), the amino-functionalized MnFe2O4 (MnFe2O4-NH2) nanozyme with outstanding peroxidase-like activity catalyzes the production of insoluble ox-DAB precipitates. The precipitates hinder interfacial electron transfer via steric hindrance and decrease the photocurrent. With specific recognition of ATP, the amount of MnFe2O4-NH2 on the electrode surface was reduced, the photocurrent was recovered and a signal-on detection mode was achieved. The aptasensor exhibits a linear range from 10-12 to 10-7 g mL-1 with a detection limit of 0.33 pg mL-1, together with satisfactory reproducibility, stability and practical applicability. This work provides a new strategy for the efficient detection of low-abundance biological small molecules and a new approach for early clinical monitoring and diagnosis of diseases.
MicroRNAs (miRNAs) regulate post-transcriptional gene expression by specifically recognizing mRNAs and have emerged as potential biomarkers for many diseases. To improve the sensitivity of disease diagnosis, simultaneous detection of multiple miRNAs is highly required. However, the conventional stem-loop reverse transcription qPCR (RT-qPCR) method cannot achieve multiplexed miRNA detection in a single run. To address these limitations, we developed a multiplexed miRNA detection method based on duplex-specific nuclease (DSN)-assisted isothermal signal amplification with HPLC coupled with UV. In this strategy, target miRNAs trigger DSN enzyme activity and hydrolysis of polyadenine (poly A) and polyguanine (poly G) sequences for the release of A and G, and this is followed by chromatographic separation and quantitative detection. The proposed method enabled the detection of target miRNAs ranging from 500 fM to 500 nM and could discriminate homologous family members and sequences with 2- or 4-base mismatches. Finally, the method was successfully applied to detect miRNAs in total RNA from MCF-7 cells, and the results were consistent with those obtained by conventional stem-loop RT-qPCR, demonstrating the favorable accuracy of the newly developed method. Based on this method, the introduction of additional DNA probes containing polydeoxythymidine (poly T) and polydeoxycytidine (poly C) sequences enables the simultaneous analysis of 4 miRNAs, thereby demonstrating considerable application potential.
Field-based environmental metabolomics offers a powerful tool for examining how organisms respond to complex mixtures of chemical and environmental stressors. When coupled with traditional ecotoxicology, metabolomics can help reveal mechanistic pathways; however, laboratory-based tests cannot fully replicate the dynamic, multifactorial conditions of natural ecosystems. This review synthesises current advances, challenges, and opportunities in applying metabolomics to ecotoxicology under real-world field conditions. We highlight the growing use of wild-caught organisms, caged exposures, mesocosms, and laboratory studies using field-collected samples to detect sub-lethal metabolic disruptions associated with contaminants such as PFAS, metals, organic pollutants, and wastewater-derived mixtures of compounds. Key themes include the sensitivity of metabolomics to early physiological changes, integration with complementary chemical and ecological data, the challenges in distinguishing natural variability from contaminant effects, the importance of establishing baselines and dose-response relationships, and the need for improved QA/QC and metadata reporting. As the methodological and logistical challenges are overcome, metabolomic profiles from field-exposed organisms are increasingly demonstrating value for environmental risk monitoring and forecasting. Environmental metabolomics has been successfully used for environmental monitoring, supporting regulatory frameworks, and identifying mechanistically grounded biomarkers of exposure and effects. However, to realise its full potential, coordinated efforts among current and future metabolomics practitioners are still needed to advance the current Metabolomics Standards Initiative (MSI) guidance. The MSI should, ideally, be expanded to include common standardised workflows, strengthen bioinformatics infrastructure, expand case studies, and fully embed and integrate metabolomics within routine environmental assessment and decision-making processes, thereby transitioning these 'academic' approaches into practical regulatory tools.
Rapid and accurate identification of pathogenic bacteria is essential for safeguarding public health. However, existing approaches, including conventional culture methods, microscopic examination, modern molecular biology techniques, and sophisticated instrumental analyses, still suffer from lengthy processing times, operational complexity, high costs, and susceptibility to interference. Such limitations impede meeting the increasing demand for rapid, sensitive, cost-effective, and user-friendly pathogenic bacterial identification across diverse application scenarios. Consequently, the development of more advanced identification methodologies remains a critical research objective. Surface-enhanced Raman spectroscopy (SERS), owing to its high sensitivity, rapid measurement capability, optical probing characteristics, and molecular fingerprint information, has become a focal point in pathogenic bacterial identification research and has been applied in clinical diagnostics, food safety, environmental monitoring, and agriculture. This review systematically highlights the latest advances in the field of SERS-based pathogenic bacterial identification, drawing on 126 articles published by the American Chemical Society, Elsevier, Wiley, and other leading publishers. It details key breakthroughs in substrate fabrication, sample enrichment strategies, and precise strain discrimination. It further highlights the development and application of artificial intelligence and machine learning in SERS over the past two years, emphasizing their potentially transformative impacts on the field. In addition, recent studies on SERS-based detection of pathogenic bacteria in complex clinical specimens, including blood, urine, and sputum, are examined, with particular attention to improvements in diagnostic sensitivity, specificity, and the feasibility of standardization. Overall, the unique advantages of SERS as a next-generation rapid and portable diagnostic platform are discussed.
Plant diseases pose a growing threat to global food security, with invasive bacterial pathogens presenting particular challenges for early detection and containment. Xylella fastidiosa is among the most destructive of these pathogens, infecting hundreds of plant species and posing a severe biosecurity risk to agricultural systems, including those in Australia. Despite its significance, routine detection still relies on laboratory-based molecular amplification methods that are slow, costly, and poorly suited to field deployment. Here, we present an amplification-free, proof-of-concept electrochemical method for detecting X. fastidiosa DNA based on potential-induced DNA adsorption onto a screen-printed gold electrode (Au-SPE). Target DNA is first isolated using magnetic beads and then rapidly adsorbed onto an Au-SPE through a 30 s cathodic potential step, enabling direct differential pulse voltammetric (DPV) readout without enzymatic amplification. The method clearly discriminates the X. fastidiosa 9a5c isolate from non-specific bacterial DNA (Xanthomonas albilineans), delivering a sensitive and selective signal within 2 minutes (30 s for adsorption plus 75 s for DPV measurement). The entire assay is completed in under 30 minutes, offering approximately fourfold faster analysis than conventional molecular amplification. When applied to spiked buffer and xylem sap (i.e., a complex biological matrix) samples, the assay maintains high analytical performance, achieving a detection limit of 100 aM without compromising specificity or sensitivity. To support on-site testing, we also introduce a low-cost, 3D-printed device for rapid xylem sap extraction, allowing direct analysis with minimal handling and seamless integration into the detection workflow. Overall, the method provides a simple, rapid, and portable diagnostic strategy that advances plant pathogen detection beyond the laboratory. With further field validation, it could support earlier intervention and strengthen biosecurity surveillance for X. fastidiosa and other high-priority pathogens.
Gangliosides are a class of glycosphingolipids highly enriched in the central nervous system and play key roles in neurological functions and pathologies. Deep profiling of gangliosides remains challenging due to their low abundance, high structural complexity, and the matrix effect. Recently, we have developed a method for cellular ganglioside enrichment using TiO2 magnetic nanoparticles; however, the large difference within the brain lipidome demands significant modification of the method. Herein, we introduce a tailored enrichment procedure which selectively depletes major brain-specific interfering lipids, thereby allowing the enrichment of gangliosides with up to four sialic acid residues. Furthermore, the integration of amide-hydrophilic interaction liquid chromatography with trapped ion mobility spectrometry and tandem mass spectrometry greatly facilitates the discovery of new ganglioside structures. When applied to porcine brain total lipid extract, we achieved the identification of 239 species across 40 subclasses, including newly discovered GD1c and O-Ac-GD1c, with 184 of them being characterized at the chain composition level. Compared to the fewer than 15 subclasses identified in brain gangliosides using non-enriched approaches, our data present the most extensive structural atlas of brain gangliosides reported to date. This approach holds promise for investigating the brain ganglioside metabolism involved in neurodevelopment, neurodegeneration, and other neurological contexts.
Micro-Raman spectroscopy (μRS) is an established analytical tool enabling facile determination of the structural ordering within carbonaceous materials, including the particulate-matter found in vehicle deposits and environmental matrices. However, if fluorescent species are present within the material under examination, μRS analysis can be at best complicated and at worst impossible. Common methods to circumvent this issue, such as changing the excitation laser wavelength and/or photobleaching, are not always possible. In this study, we demonstrate pyrolysis under high hydrogen pressures (hydropyrolysis, HyPy) as an effective thermal treatment for the removal of fluorescent species at relatively low temperatures (350 °C), without significantly altering the structure of the parent carbonaceous material. This was illustrated through μRS investigation of a series of six carbon reference samples, whereby, after HyPy, the interference from fluorescence was significantly reduced, whilst the positions, widths and intensity ratios of the diagnostic D and G bands remained largely unchanged. Application of hydropyrolysis to a series of five internal diesel injector deposits (IDIDs) enabled a μRS investigation of the physicochemical structure of the deposited carbons for the first time. Moreover, mass spectrometry analysis of the volatile species removed during HyPy of IDIDs where engine failures had occurred suggested that linear polyunsaturated n-C16 and n-C18 alkenes were likely responsible for the fluorescence. As HyPy can be readily applied to a variety of carbonaceous materials, for example, petroleum source rocks contaminated with drilling muds, the approach we describe here represents a general strategy for fluorescence suppression enabling structural investigation of carbons by μRS.