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Intentional nuclear forensics is a concept wherein the deliberate addition of benign and persistent material signatures to nuclear material can be used to reduce the time between the discovery of material outside of regulatory control and determination of its original provenance. One concept within intentional nuclear forensics involves the use of perturbed stable isotopes to generate unique isotope ratio "barcodes" to encode information (e.g., production batch, location, etc.) and track material throughout the nuclear fuel cycle. Synthesis of taggant species of nickel (Ni), molybdenum (Mo), and tungsten (W) was undertaken via a double-spike mechanism, wherein two highly enriched isotopes of interest per elemental taggant were mixed to form an enriched "double-spike" which was subsequently isotopically diluted with bulk material having a natural isotopic composition. Two taggant species perturbing isotopic ratios, alpha (α) and beta (β), for each of Ni, Mo, and W were synthesized. Independent measurements of double spikes and alpha and beta taggant species agreed within uncertainty and are clearly resolvable from natural compositions. High-precision analyses were independently performed by MC-ICP-MS at two U.S. National Laboratories, with consensus values and uncertainties calculated for all samples. Observed isotopic perturbations in the final taggant species measured on the order of hundreds to thousands of permille (‰) with respect to natural for isotope ratios of interest (e.g., ⁶⁰Ni/⁵⁸Ni, ¹⁰⁰Mo/⁹⁸Mo, ¹⁸⁶ W/¹⁸³W). Discrepancies between modeled and measured isotopic compositions were observed and are largely attributed to imprecise vendor assay values for starting materials. Using measured starting material compositions as inputs for the mixing model improved the level of agreement between predicted and measured α and β taggant isotope ratios. Overall, characterization of all taggant species demonstrates that this "barcode" concept could have viability for use in nuclear forensics. It is expected that for any two-isotope mixing array dozens of isotopic barcodes could be encoded into a material system and subsequently resolved utilizing modern mass spectrometric methods.

A new and high performance polytetrafluoroethylene (PTFE) digestor was designed and fabricated in-house for the total dissolution of granite samples for the determination of technology-critical elements (TCEs) by inductively coupled plasma optical emission spectrometry (ICP-OES). Initially, the granite sample (∼0.25 g) was placed in the PTFE digestor and added 8 mL(v/v) of 20%HF+40%HCl+10%HNO₃ acid mixture. After closing, the digestor was directly heated on a hotplate at ∼250 °C for about 2 h (hotplate digestion step (HDS)). Subsequently, the sample mixture was transferred to a graphite-bottom Teflon beaker for evaporation step (ES) at ∼180 °C to remove silica matrix followed by aqua regia treatment step (ATS) to the sample residue for the transformation of highly insoluble metal-fluoro complexes in to soluble chloro-complexes. After ATS, the sample residue was reconstituted in 3 mL of 60 % (v/v) aqua regia. The final sample digests were very clear and stable with no apparently visible fluoride precipitates indicating complete decomposition of different phases present in the granite matrix. The clear sample digests were analysed for REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Sc and Y), high field strength elements HFSEs (Ta, Ti, Zr, Nb, Hf and Th) by ICP-OES. The key parameters of the proposed digestion protocol were optimized for achieving quantitative recovery (>95 %). The proposed procedure was validated using granite based reference materials viz., NCSDC-73376, SARM-1 and JG-2. Various novelty aspects are involved in the present work which include (a) utilization of in-house PTFE digestor (b) hotplate heating with dilute acid mixtures (c) complete elimination of metal-fluoride precipitates (d) no need of expensive commercial bomb digestion systems and (e) total dissolution of granite sample for the determination of elements of highly technological relevance in ∼3 h which is much faster than what is achievable using prevailing conventional methods.

Esophageal cancer (EC), the fifth most common cause of cancer-related mortality in China, poses a significant threat to public health. Among the pathological types, esophageal squamous cell carcinoma (ESCC) is predominant, comprising approximately 90 % of cases. Screening is crucial for early detection, diagnosis and treatment, thereby reducing ESCC mortality. This study aimed to develop a rapid, accurate, and cost-effective method based on near-infrared (NIR) spectroscopy combined with aquaphotomics for ESCC screening. NIR spectra were obtained from plasma samples of both healthy controls and ESCC patients. Subsequently, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were utilized to identify the water matrix coordinates (WAMACS), thereby delineating the water absorption spectrum pattern (WASP) and constructing an aquagram. The results showed that the PLS-DA screening test model demonstrated high accuracy and precision rates of 95.12 % and 97.10 %, respectively, along with sensitivity and specificity rates of 97.10 % and 84.62 %. The area under the curve (AUC) achieved 0.9064. Aquaphotomic analysis revealed that the WASP of the healthy group predominantly exhibited strong absorption in regions indicative of strong hydrogen bonds (1460 nm, 1480 nm, 1494 nm), while the WASP of the ESCC group showed strong absorption in regions associated with strong hydrogen bonds, weak hydrogen bonds and free water, especially the regions of weak hydrogen bonds (1434 nm) and free water (1390 nm) were significantly different from those of the healthy group. The findings indicated that the rapid screening model for ESCC, integrating NIR spectroscopy with aquaphotomics, is both effective and feasible, with the WASP presenting as a potentially valuable biomarker for ESCC screening.

Diazepam (DZP) is a muscle-relaxing, anxiety-relieving sedative drug; nonetheless, it is also an addictive drug that may be abused. This work reports on the development of a novel electrochemical nanosensor for diazepam using SiO₂-encapsulated-3-mercaptopropionic acid-capped AuZnCeSeS quantum dots (QDs) overcoated with a molecularly imprinted polymer (MIP) on screen-printed carbon electrodes (SPCEs). Electrochemical, spectroscopic and electron microscopic characterization of the nanomaterial and modified electrode surface was carried out and is reported herein. Specifically, electrochemical characterization of the QDs/SPCE using cyclic voltammetry (CV) revealed that the QDs exhibit a higher electrode surface area whilst electrochemical impedance spectroscopy (EIS) characterization demonstrated a lower charge transfer resistance (R_ct). To fabricate the electrochemical nanosensor, firstly, alloyed AuZnCeSeS QDs were synthesized in the organic phase and thereafter capped with 3-mercaptopropionic acid (MPA) via a ligand exchange reaction. The MPA-AuZnCeSeS QDs were encapsulated in a SiO₂ layer to form a SiO₂-MPA AuZnCeSeS QDs system. The QDs were drop-casted onto SPCEs to form a SiO₂-MPA AuZnCeSeS QDs/SPCE transducer interface. Organic based acrylamide, used as a functional monomer, was electropolymerized via CV on the QDs/SPCE in the presence of the diazepam template with ethylene glycol dimethacrylate as a crosslinker and 2,2'-azobis(2-methylpropionitrile) as an initiator. Under optimum experimental conditions, DZP was detected using EIS and square wave voltammetry (SWV). Using a portable potentiostat and a hand-held smartphone-based potentiostat, DZP was quantitatively detected in saliva using the MIP@QDs/SPCE with a limit of detection (LOD) of 2.3 μM and 2.7 μM, respectively. The LOD for DZP from SWV analysis was 1.0 μM.

A multifunctional microfluidic chip integrated with perfusion cell culture and in situ SERS detection of cell secretion was designed and developed for the detection of IL-6 secretion from LPS-stimulation of A549 cells in this paper. Researching works were focused on A549 cell activity and secretion in the constructed LPS-stimulated A549 cells model. On the designed microchip, a bubble trap chamber was designed to remove the bubbles in the culture medium which could also be simultaneously preheated by a split hot plate. Then, a long-time perfusion culture process of 549 cells could be realized. Under the optimized conditions the A549 cells could be cultured and kept in good activity for more than 36 h. Subsequently, the model of interaction between LPS and A549 cells was established on the designed microchip. When LPS-stimulated A549 cells, the IL-6 which was one of the secretions formed in this process was detected quantitatively by SERS spectral technique. The silver-coated gold nano-stars were prepared and taken as a sensitive enhancing probe for the SERS detection of IL-6 secreted from LPS-stimulated A549 cells. The immunomagnetic beads, IL-6 antigen, and SERS probes were mixed and incubated in the microchip and form a sandwich structure which was captured by the permanent magnet in the detection zone for SERS detection. The reference material of IL-6 was used to establish the calibration curve, and the linear range and detection limit were 1-10000 pg/mL and 0.75 pg/mL, respectively. Then, the IL-6 secretion from LPS-stimulated A549 cells was detected hourly for 7 h by this established method. The process of LPS stimulation of A594 cells did not lead to a sustained increase in the SERS spectral signature of IL-6. Instead, IL6 secretion initially increased sharply, then decreased and eventually stabilized. It could be due to a potential mechanism that the cells self-regulated to mitigate the inflammatory effects in response to sustained stimulation. The proposed multifunctional microfluidic chip, characterized by high sensitivity and the ability to perform continuous hourly detection, exhibited significant application prospects in the study of external stimulation on cells.

Glutathione (GSH) is a bioactive tripeptide with important physiological functions in animals, plants, and microorganisms. GSH participates in various biochemical reactions in vivo and is known for its antioxidant, anti-allergy, and detoxification properties. This study introduces an innovative photoelectrochemical (PEC) method for GSH detection, leveraging a fluorine-doped tin oxide (FTO) electrode enhanced by TiO₂ nanoflowers and graphitic carbon nitride quantum dots (g-CNQDs). This design formed a type-II heterojunction, which facilitated efficient charge separation and transport. Furthermore, incorporating TiO₂ nanoflowers increases the surface area, while adding g-CNQDs led to a narrowing of the semiconductor bandgap. The fabricated electrode exhibits highly attractive photo-electrocatalytic activity towards GSH detection in neutral media at a low potential bias. The developed PEC sensor demonstrates a wide linear range of 1.0 × 10^-13 to 5 × 10^-5 mol L^-1, a low detection limit of 5.0 fmol L^-1, and high sensitivity. These remarkable analytical characteristics highlight the potential of this PEC platform for sensitive and selective GSH detection in various biomedical and environmental applications.

This study explores a quick, low-cost method to detect Alzheimer's disease (AD) by evaluating the accomplishment of a Gate-Stack (GS) Field Effect Transistor (FET). We investigate Single-Metal (SM), Dual-Metal (DM), and Tri-Metal Double Gate (DG) configurations, where cavities have been created by etching the oxide layer underneath the gate to immobilize grey matter samples collected through Solid-phase microextraction (SPME). Healthy and AD-affected grey matter have different dielectric characteristics at high frequencies. The dielectric constant of the etched nanocavities changes when the sample, which was formerly filled with air, is immobilized in the nanocavities. The alteration in the device drain current as well as performance at 2.4 GHz has been connected to the specimen's modified dielectric constant. To distinguish between the grey matter samples from AD patients and healthy individuals, the I_ON/I_OFF of the suggested device along with the variation in device drain current, has been utilized as the foundation for the identification. The SM configuration has been examined by varying the cavity orientation and gate oxide stacking. To monitor the functioning of the suggested devices, the gate metal of the DM and TM devices has been altered, and a comparison has been made between SM, DM, and TM structures. The other recorded work from literature has been compared with the suggested detection technique. To ascertain whether the sample is impacted by AD, the proposed method can be used as a point of care (POC) diagnosis.

Exosomes, extracellular vesicles crucial for intercellular communication, are emerging as significant biomarkers for disease diagnosis, especially in cancer. This study presented a dual-mode exosome detection platform using polydopamine microspheres doped with iron and zinc ions (PDA@Fe@Zn). These materials served as both artificial receptors for nucleic acid aptamers and nanozymes with peroxidase-like activity. By integrating colorimetric and fluorescence detection, the platform enables cross-validation of results. PDA@Fe@Zn nanozymes catalyzed the TMB-H₂O₂ reaction under acidic conditions, producing a colorimetric signal proportional to exosome concentration. Concurrently, the fluorescence of FAM-labeled aptamers was dynamically quenched by PDA@Fe@Zn and the presence of exosomes restores the fluorescence signal for a "turn-on" detection mode. DNase I amplified detection signals by cleaving bound exosomes for multiple cycles, achieving a limit of detection (LOD) of 4.7 × 10⁴ particles/mL for colorimetric detection and 2.2 × 10⁴ particles/mL for fluorescence detection. Notably, the colorimetric platform revealed that the relative expression of the CD63 protein on exosomes from breast cancer cells MCF-7 and MDA-MB-231 was approximately 2.7 and 2.4 times higher, respectively, than in normal breast cells MCF-10A; similar fold changes of 2.9 and 2.4 were observed with fluorescence detection, underscoring the robustness of the dual-mode system. The platform demonstrated rapid detection (within 30 min), high sensitivity, strong anti-interference capability, and the ability to distinguish exosomes from cancerous and normal cells effectively.

Porcine epidemic diarrhea virus (PEDV) and porcine rotavirus (PoRV) are the two main pathogens causing porcine diarrhea, which are characterized by high morbidity and mortality. Most of the diagnostic methods available are limited to the laboratory or fail to highlight their advantages in terms of target species, detection time, sensitivity, and stability. To meet the demand for rapid on-site diagnosis of PEDV and PoRV co-infection, a surface-enhanced Raman scattering (SERS) immunochromatographic sensor based on gold magnetic nanoparticles (MNPs) was developed. The sensor is dual-mode, detecting on the basis of color signals by the naked eye and Raman signals. After a series of optimizations, the constructed sensor could perform simultaneous qualitative and quantitative detection of PEDV and PoRV in just 18 min, with visualized (color signals observed by the naked eye) limits of detection (LOD) of 3.13 × 10² TCID₅₀/mL and 4.69 × 10² copies/μL, respectively. The LOD based on Raman signal analysis was as low as 4.63 × 10¹ TCID₅₀/mL and 3.30 × 10² copies/μL for PEDV and PoRV, respectively. In addition, the sensor exhibited excellent specificity without cross-reactivity with common pathogens. The overall compliance rate with RT-PCR was 92.1 % (35/38) for 38 clinical samples. Therefore, the sensor is characterized by high sensitivity, specificity, reproducibility, and accuracy, making it suitable for the simultaneous rapid on-site detection of PEDV and PoRV.